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Feng S, Xu X, Li X, Deng G, Xia C, Zhou L, Chen T, Gao T, Yuan M, Cao X, Ding C. Structure elucidation and antioxidant activity of a polysaccharide from Penthorum chinense Pursh. Int J Biol Macromol 2024; 264:130720. [PMID: 38460626 DOI: 10.1016/j.ijbiomac.2024.130720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 03/05/2024] [Accepted: 03/06/2024] [Indexed: 03/11/2024]
Abstract
Penthorum chinense Pursh is a traditional Miao medicine, mainly used in the treatment of liver diseases. In this study, an acidic heteropolysaccharide PCPP was isolated from P. chinense with an average molecular weight of 14.96 kDa. PCPP contained arabinogalactan and homogalacturonan segments, which is formed by 4-Galp-(1 → 5)-Araf-1 and 3,6-Galp-(1 → 6)-Galp-1,3 glycosidic linkage. A variety of side chains, including t-Glcp-(1 → 4)-Glcp-(1 → 4)-GlcpA-1, t-Xylp-(1→, and 2-Manp-(1 → 4)-GalpA-1,3 linked to the O-3 and O-6 of 3,6-Galp. The antioxidant activity measurement in three models demonstrated that PCPP exhibited ROS scavenging capacity, antioxidant ability in the cellular model, enhancement of oxidative stress resistance, and healthspan-promoting effect in the worm model. These results provided the theoretical fundament of PCPP as a potential natural antioxidant.
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Affiliation(s)
- Shiling Feng
- College of Life Science, Sichuan Agricultural University, Ya'an 625014, Sichuan Province, China
| | - Xiaoyan Xu
- College of Life Science, Sichuan Agricultural University, Ya'an 625014, Sichuan Province, China; State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, Jiangsu Province, China
| | - Xiao Li
- College of Life Science, Sichuan Agricultural University, Ya'an 625014, Sichuan Province, China
| | - Guanfeng Deng
- College of Life Science, Sichuan Agricultural University, Ya'an 625014, Sichuan Province, China
| | - Chen Xia
- Institute of Agro-Products Processing Science and Technology, Sichuan Academy of Agricultural Sciences, Chengdu 610066, Sichuan Province, China.
| | - Lijun Zhou
- College of Life Science, Sichuan Agricultural University, Ya'an 625014, Sichuan Province, China
| | - Tao Chen
- College of Life Science, Sichuan Agricultural University, Ya'an 625014, Sichuan Province, China
| | - Tao Gao
- College of Life Science, Sichuan Agricultural University, Ya'an 625014, Sichuan Province, China
| | - Ming Yuan
- College of Life Science, Sichuan Agricultural University, Ya'an 625014, Sichuan Province, China
| | - Xiaohan Cao
- College of Life Science, Sichuan Agricultural University, Ya'an 625014, Sichuan Province, China
| | - Chunbang Ding
- College of Life Science, Sichuan Agricultural University, Ya'an 625014, Sichuan Province, China.
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2
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Viragh E, Asztalos L, Fenckova M, Szlanka T, Gyorgypal Z, Kovacs K, IntHout J, Cizek P, Konda M, Szucs E, Zvara A, Biro J, Csapo E, Lukacsovich T, Hegedus Z, Puskas L, Schenck A, Asztalos Z. Pre-Pulse Inhibition of an escape response in adult fruit fly, Drosophila melanogaster. RESEARCH SQUARE 2024:rs.3.rs-3853873. [PMID: 38343805 PMCID: PMC10854311 DOI: 10.21203/rs.3.rs-3853873/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/19/2024]
Abstract
Pre-Pulse Inhibition (PPI) is a neural process where suppression of a startle response is elicited by preceding the startling stimulus (Pulse) with a weak, non-startling one (Pre-Pulse). Defective PPI is widely employed as a behavioural endophenotype in humans and mammalian disorder-relevant models for neuropsychiatric disorders. We have developed a user-friendly, semi-automated, high-throughput-compatible Drosophila light-off jump response PPI paradigm, with which we demonstrate that PPI, with similar parameters measured in mammals, exists in adults of this model organism. We report that Drosophila PPI is affected by reduced expression of Dysbindin and both reduced and increased expression of Nmdar1 (N-methyl-D-aspartate receptor 1), perturbations associated with schizophrenia. Studying the biology of PPI in an organism that offers a plethora of genetic tools and a complex and well characterized connectome will greatly facilitate our efforts to gain deeper insight into the aetiology of human mental disorders, while reducing the need for mammalian models.
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Affiliation(s)
- Erika Viragh
- Institute of Biochemistry, HUN-REN Biological Research Centre, Szeged, Hungary
- Aktogen Hungary Ltd., Szeged, Hungary
| | - Lenke Asztalos
- Aktogen Hungary Ltd., Szeged, Hungary
- Aktogen Ltd., Department of Genetics, University of Cambridge, Cambridge, United Kingdom; Current address: Aktogen Ltd. Ramsey, Huntingdon, United Kingdom
| | - Michaela Fenckova
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
- Department of Molecular Biology and Genetics, Faculty of Science, University of South Bohemia in Ceske Budejovice, Ceske Budejovice, Czechia
| | - Tamas Szlanka
- Institute of Biochemistry, HUN-REN Biological Research Centre, Szeged, Hungary
- Aktogen Hungary Ltd., Szeged, Hungary
| | - Zoltan Gyorgypal
- Institute of Biophysics & Core Facilities, HUN-REN Biological Research Centre, Szeged, Hungary
| | - Karoly Kovacs
- Institute of Biochemistry, HUN-REN Biological Research Centre, Szeged, Hungary
- HCEMM-BRC Metabolic Systems Biology Lab, Szeged, Hungary
| | - Joanna IntHout
- Department for Health Evidence (HEV), Radboud University Medical Center, Nijmegen, The Netherlands
| | - Pavel Cizek
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Mihaly Konda
- Aktogen Hungary Ltd., Szeged, Hungary
- Voalaz Ltd., Szeged, Hungary
| | | | - Agnes Zvara
- Laboratory of Functional Genomics, HUN-REN Biological Research Centre Szeged, Hungary
| | | | | | | | - Zoltan Hegedus
- Institute of Biophysics & Core Facilities, HUN-REN Biological Research Centre, Szeged, Hungary
| | - Laszlo Puskas
- Laboratory of Functional Genomics, HUN-REN Biological Research Centre Szeged, Hungary
| | - Annette Schenck
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Zoltan Asztalos
- Institute of Biochemistry, HUN-REN Biological Research Centre, Szeged, Hungary
- Aktogen Hungary Ltd., Szeged, Hungary
- Aktogen Ltd., Department of Genetics, University of Cambridge, Cambridge, United Kingdom; Current address: Aktogen Ltd. Ramsey, Huntingdon, United Kingdom
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3
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Bonnard E, Liu J, Zjacic N, Alvarez L, Scholz M. Automatically tracking feeding behavior in populations of foraging C. elegans. eLife 2022; 11:e77252. [PMID: 36083280 PMCID: PMC9462848 DOI: 10.7554/elife.77252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 08/15/2022] [Indexed: 11/13/2022] Open
Abstract
Caenorhabditis elegans feeds on bacteria and other small microorganisms which it ingests using its pharynx, a neuromuscular pump. Currently, measuring feeding behavior requires tracking a single animal, indirectly estimating food intake from population-level metrics, or using restrained animals. To enable large throughput feeding measurements of unrestrained, crawling worms on agarose plates at a single worm resolution, we developed an imaging protocol and a complementary image analysis tool called PharaGlow. We image up to 50 unrestrained crawling worms simultaneously and extract locomotion and feeding behaviors. We demonstrate the tool's robustness and high-throughput capabilities by measuring feeding in different use-case scenarios, such as through development, with genetic and chemical perturbations that result in faster and slower pumping, and in the presence or absence of food. Finally, we demonstrate that our tool is capable of long-term imaging by showing behavioral dynamics of mating animals and worms with different genetic backgrounds. The low-resolution fluorescence microscopes required are readily available in C. elegans laboratories, and in combination with our python-based analysis workflow makes this methodology easily accessible. PharaGlow therefore enables the observation and analysis of the temporal dynamics of feeding and locomotory behaviors with high-throughput and precision in a user-friendly system.
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Affiliation(s)
- Elsa Bonnard
- Max Planck Research Group Neural Information Flow, Max Planck Institute for Neurobiology of Behavior – caesarBonnGermany
| | - Jun Liu
- Max Planck Research Group Neural Information Flow, Max Planck Institute for Neurobiology of Behavior – caesarBonnGermany
| | - Nicolina Zjacic
- Max Planck Research Group Neural Information Flow, Max Planck Institute for Neurobiology of Behavior – caesarBonnGermany
- Institute of Medical Genetics, University of ZurichZurichSwitzerland
| | - Luis Alvarez
- Max Planck Research Group Neural Information Flow, Max Planck Institute for Neurobiology of Behavior – caesarBonnGermany
| | - Monika Scholz
- Max Planck Research Group Neural Information Flow, Max Planck Institute for Neurobiology of Behavior – caesarBonnGermany
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Zirintunda G, Biryomumaisho S, Kasozi KI, Batiha GES, Kateregga J, Vudriko P, Nalule S, Olila D, Kajoba M, Matama K, Kwizera MR, Ghoneim MM, Abdelhamid M, Zaghlool SS, Alshehri S, Abdelgawad MA, Acai-Okwee J. Emerging Anthelmintic Resistance in Poultry: Can Ethnopharmacological Approaches Offer a Solution? Front Pharmacol 2022; 12:774896. [PMID: 35237147 PMCID: PMC8883056 DOI: 10.3389/fphar.2021.774896] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 11/30/2021] [Indexed: 01/09/2023] Open
Abstract
Limited pharmacological studies have been conducted on plant species used against poultry helminths. The objective of this study was to provide a basis for plant based anthelmintics as possible alternatives against poultry anthelmintic resistance. The study justified the need for alternative anthelmintics. The study places emphasis on the increasing anthelmintic resistance, mechanism of resistance, and preparational protocols for plant anthelmintics and their associated mechanism of action. Pharmaceutical studies on plants as alternative therapies for the control of helminth parasites have not been fully explored especially in several developing countries. Plants from a broad range of species produce a wide variety of compounds that are potential anthelmintics candidates. Important phenolic acids have been found in Brassica rapa L. and Terminalia avicenniodes Guill. and Perri that affect the cell signaling pathways and gene expression. Benzo (c) phenanthridine and isoquinoline alkaloids are neurotoxic to helminths. Steroidal saponins (polyphyllin D and dioscin) interact with helminthic mitochondrial activity, alter cell membrane permeability, vacuolation and membrane damage. Benzyl isothiocyanate glucosinolates interfere with DNA replication and protein expression, while isoflavones from Acacia oxyphylla cause helminth flaccid paralysis, inhibit energy generation, and affect calcium utilization. Condensed tannins have been shown to cause the death of nematodes and paralysis leading to expulsion from the gastro-intestinal tract. Flavonoids from Chenopodium album L and Mangifera indica L act through the action of phosphodiesterase and Ca2+-ATPase, and flavonoids and tannins have been shown to act synergistically and are complementary to praziquantel. Artemisinins from Artemisia cina O. Berg are known to disrupt mitochondrial ATP production. Terpenoids from Cucurbita moschata L disrupt neurotransmission leading to paralysis as well as disruption of egg hatching. Yeast particle encapsulated terpenes are effective for the control of albendazole-resistant helminths.
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Affiliation(s)
- Gerald Zirintunda
- School of Veterinary Medicine and Animal Resources, Makerere University, Kampala, Uganda
| | - Savino Biryomumaisho
- School of Veterinary Medicine and Animal Resources, Makerere University, Kampala, Uganda
| | - Keneth Iceland Kasozi
- Infection Medicine, Deanery of Biomedical Sciences, College of Medicine and Veterinary Medicine, University of Edinburgh, Scotland, United Kingdom
- School of Medicine, Kabale University, Kabale, Uganda
| | - Gaber El-Saber Batiha
- Department of Pharmacology and Therapeutics, Faculty of Veterinary Medicine, Damanhour University, Albeheira, Egypt
| | - John Kateregga
- School of Veterinary Medicine and Animal Resources, Makerere University, Kampala, Uganda
| | - Patrick Vudriko
- School of Veterinary Medicine and Animal Resources, Makerere University, Kampala, Uganda
| | - Sarah Nalule
- School of Veterinary Medicine and Animal Resources, Makerere University, Kampala, Uganda
| | - Deogracious Olila
- Department of Animal Production and Management, Faculty of Agriculture and Animal Sciences, Busitema University, Soroti, Uganda
| | - Mariam Kajoba
- School of Pharmacy, Kampala International University Western Campus, Bushenyi, Uganda
| | - Kevin Matama
- School of Pharmacy, Kampala International University Western Campus, Bushenyi, Uganda
| | - Mercy Rukundo Kwizera
- School of Pharmacy, Kampala International University Western Campus, Bushenyi, Uganda
| | - Mohammed M. Ghoneim
- Biology Department, Faculty of Applied Sciences, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Mahmoud Abdelhamid
- Department of Parasitology, Faculty of Veterinary Medicine, Aswan University, Aswan, Egypt
| | - Sameh S. Zaghlool
- Pharmacology and Toxicology Department, Faculty of Pharmacy, Modern University for Technology and Information, Cairo, Egypt
| | - Sultan Alshehri
- Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Mohamed A. Abdelgawad
- Department of Pharmaceutical Chemistry, College of Pharmacy, Jouf University, Al Jouf, Saudi Arabia
| | - James Acai-Okwee
- School of Veterinary Medicine and Animal Resources, Makerere University, Kampala, Uganda
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5
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Millet JRM, Romero LO, Lee J, Bell B, Vásquez V. C. elegans PEZO-1 is a mechanosensitive ion channel involved in food sensation. J Gen Physiol 2022; 154:212890. [PMID: 34854875 PMCID: PMC8647359 DOI: 10.1085/jgp.202112960] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 10/28/2021] [Accepted: 11/12/2021] [Indexed: 01/02/2023] Open
Abstract
PIEZO channels are force sensors essential for physiological processes, including baroreception and proprioception. The Caenorhabditis elegans genome encodes an orthologue gene of the Piezo family, pezo-1, which is expressed in several tissues, including the pharynx. This myogenic pump is an essential component of the C. elegans alimentary canal, whose contraction and relaxation are modulated by mechanical stimulation elicited by food content. Whether pezo-1 encodes a mechanosensitive ion channel and contributes to pharyngeal function remains unknown. Here, we leverage genome editing, genetics, microfluidics, and electropharyngeogram recording to establish that pezo-1 is expressed in the pharynx, including in a proprioceptive-like neuron, and regulates pharyngeal function. Knockout (KO) and gain-of-function (GOF) mutants reveal that pezo-1 is involved in fine-tuning pharyngeal pumping frequency, as well as sensing osmolarity and food mechanical properties. Using pressure-clamp experiments in primary C. elegans embryo cultures, we determine that pezo-1 KO cells do not display mechanosensitive currents, whereas cells expressing wild-type or GOF PEZO-1 exhibit mechanosensitivity. Moreover, infecting the Spodoptera frugiperda cell line with a baculovirus containing the G-isoform of pezo-1 (among the longest isoforms) demonstrates that pezo-1 encodes a mechanosensitive channel. Our findings reveal that pezo-1 is a mechanosensitive ion channel that regulates food sensation in worms.
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Affiliation(s)
- Jonathan R M Millet
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN
| | - Luis O Romero
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN.,Integrated Biomedical Sciences Graduate Program, College of Graduate Health Sciences, University of Tennessee Health Science Center, Memphis, TN
| | - Jungsoo Lee
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN
| | - Briar Bell
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN.,Integrated Biomedical Sciences Graduate Program, College of Graduate Health Sciences, University of Tennessee Health Science Center, Memphis, TN
| | - Valeria Vásquez
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN
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6
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Izquierdo PG, Calahorro F, Thisainathan T, Atkins JH, Haszczyn J, Lewis CJ, Tattersall JEH, Green AC, Holden-Dye L, O'Connor V. Cholinergic signaling at the body wall neuromuscular junction distally inhibits feeding behavior in Caenorhabditis elegans. J Biol Chem 2021; 298:101466. [PMID: 34864060 PMCID: PMC8801469 DOI: 10.1016/j.jbc.2021.101466] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 11/13/2021] [Accepted: 11/30/2021] [Indexed: 12/27/2022] Open
Abstract
Complex biological functions within organisms are frequently orchestrated by systemic communication between tissues. In the model organism Caenorhabditis elegans, the pharyngeal and body wall neuromuscular junctions are two discrete structures that control feeding and locomotion, respectively. Separate, the well-defined neuromuscular circuits control these distinct tissues. Nonetheless, the emergent behaviors, feeding and locomotion, are coordinated to guarantee the efficiency of food intake. Here, we show that pharmacological hyperactivation of cholinergic transmission at the body wall muscle reduces the rate of pumping behavior. This was evidenced by a systematic screening of the effect of the cholinesterase inhibitor aldicarb on the rate of pharyngeal pumping on food in mutant worms. The screening revealed that the key determinants of the inhibitory effect of aldicarb on pharyngeal pumping are located at the body wall neuromuscular junction. In fact, the selective stimulation of the body wall muscle receptors with the agonist levamisole inhibited pumping in a lev-1-dependent fashion. Interestingly, this response was independent of unc-38, an alpha subunit of the nicotinic receptor classically expressed with lev-1 at the body wall muscle. This implies an uncharacterized lev-1-containing receptor underpins this effect. Overall, our results reveal that body wall cholinergic transmission not only controls locomotion but simultaneously inhibits feeding behavior.
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Affiliation(s)
- Patricia G Izquierdo
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom.
| | - Fernando Calahorro
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Thibana Thisainathan
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
| | - James H Atkins
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Johanna Haszczyn
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Christian J Lewis
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
| | - John E H Tattersall
- Dstl, Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire, United Kingdom
| | - A Christopher Green
- Dstl, Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire, United Kingdom
| | - Lindy Holden-Dye
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Vincent O'Connor
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
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7
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Fueser H, Rauchschwalbe MT, Höss S, Traunspurger W. Food bacteria and synthetic microparticles of similar size influence pharyngeal pumping of Caenorhabditis elegans. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2021; 235:105827. [PMID: 33882407 DOI: 10.1016/j.aquatox.2021.105827] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 03/30/2021] [Accepted: 04/01/2021] [Indexed: 06/12/2023]
Abstract
Toxicity tests using the model organism Caenorhabditis elegans have shown that exposure to small microplastics such as polystyrene (PS) beads lead to high body burdens and dietary restrictions that in turn inhibit reproduction. Pharyngeal pumping is the key mechanism of C. elegans for governing the uptake of food and other particles and can be easily monitored by determining the pumping rates. In this study, pharyngeal pumping of C. elegans was examined in response to increasing quantities of food bacteria (E. coli: 106-1010 cells ml-1) and synthetic particles (107-109 beads ml-1) of similar size (1 µm). While the average pumping rate of C. elegans exposed to E. coli depended on the density of the bacterial cells, this was not the case for the synthetic beads. At 107 items ml-1, bacterial cells and synthetic beads triggered a basic stimulation of the pumping rate, independent of the nutritional value of the particle. At quantities >107 items ml-1, however, the nutritional value was essential to maximize the pumping rate, as it was upregulated only by E. coli cells, which can be chemosensorially recognized by C. elegans. Given the unselective uptake of all particles in the size range of bacteria, restricting the pumping rates for particles with low nutritional value to a basic rate, prevents the nematodes from wasting energy by high-frequency pumping, but still allows a food-quality screening at low food levels.
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Affiliation(s)
- Hendrik Fueser
- Bielefeld University, Animal Ecology, Konsequenz 45, 33615 Bielefeld, Germany.
| | | | - Sebastian Höss
- Bielefeld University, Animal Ecology, Konsequenz 45, 33615 Bielefeld, Germany; Ecossa, Giselastr. 6, 82319 Starnberg, Germany
| | - Walter Traunspurger
- Bielefeld University, Animal Ecology, Konsequenz 45, 33615 Bielefeld, Germany
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8
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Hu D, Chao Y, Zhang B, Wang C, Qi Y, Ente M, Zhang D, Li K, Mok KM. Effects of Gasterophilus pecorum infestation on the intestinal microbiota of the rewilded Przewalski's horses in China. PLoS One 2021; 16:e0251512. [PMID: 33974667 PMCID: PMC8112688 DOI: 10.1371/journal.pone.0251512] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 04/27/2021] [Indexed: 12/11/2022] Open
Abstract
Horse botflies have been a threat to the Przewalski’s horses in the Kalamaili Nature Reserve in Xinjiang of China since their reintroduction to the original range. As larvae of these parasites could infest the intestine of a horse for months, they could interact with and alter the structure and composition of its intestinal microbiota, affecting adversely its health. Nonetheless, there are no such studies on the rewilded Przewalski’s horses yet. For the first time, this study characterizes the composition of the intestinal microbiota of 7 rewilded Przewalski’s horses infected severely by Gasterophilus pecorum following and prior to their anthelmintic treatment. Bioinformatics analyses of the sequence data obtained by amplicon high throughput sequencing of bacterial 16S rRNA genes showed that G. pecorum infestation significantly increased the richness of the intestinal microbial community but not its diversity. Firmicutes and Bacteroidetes were found the dominant phyla as in other animals, and the parasitic infestation decreased the F/B ratio largely by over 50%. Large reduction in relative abundances of the two genera Streptococcus and Lactobacillus observed with G. pecorum infestation suggested possible changes in colic and digestion related conditions of the infected horses. Variations on the relative abundance of the genus groups known to be pathogenic or symbiotic showed that adverse impact of the G. pecorum infestation could be associated with reduction of the symbiotic genera Lactobacillus and Bifidobacterium that are probiotics and able to promote immunity against parasitic infection.
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Affiliation(s)
- Dini Hu
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China
| | - Yuzhu Chao
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China
| | - Boru Zhang
- Qinhuangdao Forestry Bureau, Qinhuangdao, China
| | - Chen Wang
- Altay Management Station of Mt. Kalamaili Ungulate Nature Reserve, Altay, China
| | - Yingjie Qi
- Altay Management Station of Mt. Kalamaili Ungulate Nature Reserve, Altay, China
| | - Make Ente
- Xinjiang Research Centre for Breeding Przewalski’s Horse, Urumqi, China
| | - Dong Zhang
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China
| | - Kai Li
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China
- * E-mail: (KL); (KMM)
| | - Kai Meng Mok
- Department of Civil and Environmental Engineering, University of Macau, Macao, China
- * E-mail: (KL); (KMM)
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9
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Aghayeva U, Bhattacharya A, Sural S, Jaeger E, Churgin M, Fang-Yen C, Hobert O. DAF-16/FoxO and DAF-12/VDR control cellular plasticity both cell-autonomously and via interorgan signaling. PLoS Biol 2021; 19:e3001204. [PMID: 33891586 PMCID: PMC8099054 DOI: 10.1371/journal.pbio.3001204] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 05/05/2021] [Accepted: 03/23/2021] [Indexed: 01/08/2023] Open
Abstract
Many cell types display the remarkable ability to alter their cellular phenotype in response to specific external or internal signals. Such phenotypic plasticity is apparent in the nematode Caenorhabditis elegans when adverse environmental conditions trigger entry into the dauer diapause stage. This entry is accompanied by structural, molecular, and functional remodeling of a number of distinct tissue types of the animal, including its nervous system. The transcription factor (TF) effectors of 3 different hormonal signaling systems, the insulin-responsive DAF-16/FoxO TF, the TGFβ-responsive DAF-3/SMAD TF, and the steroid nuclear hormone receptor, DAF-12/VDR, a homolog of the vitamin D receptor (VDR), were previously shown to be required for entering the dauer arrest stage, but their cellular and temporal focus of action for the underlying cellular remodeling processes remained incompletely understood. Through the generation of conditional alleles that allowed us to spatially and temporally control gene activity, we show here that all 3 TFs are not only required to initiate tissue remodeling upon entry into the dauer stage, as shown before, but are also continuously required to maintain the remodeled state. We show that DAF-3/SMAD is required in sensory neurons to promote and then maintain animal-wide tissue remodeling events. In contrast, DAF-16/FoxO or DAF-12/VDR act cell-autonomously to control anatomical, molecular, and behavioral remodeling events in specific cell types. Intriguingly, we also uncover non-cell autonomous function of DAF-16/FoxO and DAF-12/VDR in nervous system remodeling, indicating the presence of several insulin-dependent interorgan signaling axes. Our findings provide novel perspectives into how hormonal systems control tissue remodeling.
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Affiliation(s)
- Ulkar Aghayeva
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, New York, United States of America
| | - Abhishek Bhattacharya
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, New York, United States of America
| | - Surojit Sural
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, New York, United States of America
| | - Eliza Jaeger
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, New York, United States of America
| | - Matthew Churgin
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Christopher Fang-Yen
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Oliver Hobert
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, New York, United States of America
- * E-mail:
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10
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Rauchschwalbe MT, Fueser H, Traunspurger W, Höss S. Bacterial consumption by nematodes is disturbed by the presence of polystyrene beads: The roles of food dilution and pharyngeal pumping. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 273:116471. [PMID: 33460876 DOI: 10.1016/j.envpol.2021.116471] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 01/04/2021] [Accepted: 01/06/2021] [Indexed: 06/12/2023]
Abstract
Microplastics (MPs; <5 mm) released into freshwaters from anthropogenic sources accumulate in sediments, where they may pose an environmental threat to benthic organisms, such as nematodes. Several studies have examined the effects of nano- and microplastics on the nematode Caenorhabditis elegans, whereas reduced food availability was suggested as a possible explanation for the observed inhibitory effects. Therefore, this study should clarify whether micro-beads of different sizes (1.0 and 6.0 μm in diameter) and materials (polystyrene PS, silica) are able to interfere with the feeding of C. elegans on its bacterial diet (Escherichia coli), and, by this, lowering its consumption rate within 7 h of exposure. Moreover, it was examined whether an inhibited bacterial consumption was caused by a reduction of the nematode's pumping rate, as a primary indicator of food ingestion. Bacterial consumption by C. elegans was significantly decreased in the presence of 1.0- and 6.0-μm PS beads (49-67% lower bacterial consumption compared to control), whereas in the presence of 1.0-μm silica beads feeding was not impeded. Interestingly, the pumping rate was significantly lower in the presence of non-ingestible 6.0-μm PS beads with 161 ± 16 pumps min-1, while it was largely unchanged for nematodes exposed to ingestible 1.0-μm PS beads with 205 ± 12 pumps min-1, compared to control conditions with 210 ± 18 pumps min-1, respectively. As reduced bacterial consumption leads to generally lower energy reserves in C. elegans, these results allow to link observed inhibitory effects of MPs on the nematodes to a lower food availability. Such indirect, food-web related, effects of MPs should raise concern of ecological consequences in natural habitats, where temporal food deficiencies can occur. Consequently, disturbances in food availability and feeding efficiency should be regarded as important parameters in environmental risk assessments focusing on MPs.
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Affiliation(s)
| | - Hendrik Fueser
- Bielefeld University, Animal Ecology, Konsequenz 45, 33615, Bielefeld, Germany
| | - Walter Traunspurger
- Bielefeld University, Animal Ecology, Konsequenz 45, 33615, Bielefeld, Germany
| | - Sebastian Höss
- Bielefeld University, Animal Ecology, Konsequenz 45, 33615, Bielefeld, Germany; Ecossa, Giselastr.6, 82319, Starnberg, Germany
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11
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McClanahan PD, Dubuque JM, Kontogiorgos-Heintz D, Habermeyer BF, Xu JH, Ma AM, Raizen DM, Fang-Yen C. A quiescent state following mild sensory arousal in Caenorhabditis elegans is potentiated by stress. Sci Rep 2020; 10:4140. [PMID: 32139752 PMCID: PMC7057961 DOI: 10.1038/s41598-020-60994-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Accepted: 02/14/2020] [Indexed: 11/16/2022] Open
Abstract
An animal's behavioral and physiological response to stressors includes changes to its responses to stimuli. How such changes occur is not well understood. Here we describe a Caenorhabditis elegans quiescent behavior, post-response quiescence (PRQ), which is modulated by the C. elegans response to cellular stressors. Following an aversive mechanical or blue light stimulus, worms respond first by briefly moving, and then become more quiescent for a period lasting tens of seconds. PRQ occurs at low frequency in unstressed animals, but is more frequent in animals that have experienced cellular stress due to ultraviolet light exposure as well as in animals following overexpression of epidermal growth factor (EGF). PRQ requires the function of the carboxypeptidase EGL-21 and the calcium-activated protein for secretion (CAPS) UNC-31, suggesting it has a neuropeptidergic mechanism. Although PRQ requires the sleep-promoting neurons RIS and ALA, it is not accompanied by decreased arousability, and does not appear to be homeostatically regulated, suggesting that it is not a sleep state. PRQ represents a simple, tractable model for studying how neuromodulatory states like stress alter behavioral responses to stimuli.
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Affiliation(s)
- Patrick D. McClanahan
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA USA
| | - Jessica M. Dubuque
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA USA
| | - Daphne Kontogiorgos-Heintz
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA USA
| | - Ben F. Habermeyer
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA USA
| | - Joyce H. Xu
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA USA
| | - Anthony M. Ma
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA USA
| | - David M. Raizen
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA USA
| | - Christopher Fang-Yen
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA USA
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA USA
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12
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Ishikawa I, Iwasa M. Toxicological effect of ivermectin on the survival, reproduction, and feeding activity of four species of dung beetles (Coleoptera: Scarabaeidae and Geotrupidae) in Japan. BULLETIN OF ENTOMOLOGICAL RESEARCH 2020; 110:106-114. [PMID: 31190655 DOI: 10.1017/s0007485319000385] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We investigated the effects of the antiparasitic drug ivermectin on the dung beetles Copris acutidens Motschulsky, Onthophagus bivertex Heyden, O. lenzii Harold and Phelotrupes auratus auratus Motschulsky in Japan. Ivermectin was detected in cattle dung from 1 to 3 or 7 days post-treatment, with a peak at 3 days post-treatment in two pour-on administrations (500 µg kg-1). In C. acutidens, adult survivals and numbers of brood balls were significantly reduced in dung collected at 3 and 7 days post-treatment, and adult emergence rates were significantly decreased in dung collected at 7 and 14 days post-treatment. Feeding activity of C. acutidens was inhibited in dung collected at 3 days post-treatment, but was not significantly different from that seen in control dung at 7 and 14 days post-treatment. In O. bivertex and O. lenzii, there were no effects of ivermectin on adult survival or feeding activities, but the numbers of brood balls of O. bivertex constructed in dung collected at 3 and 7 days post-treatment were significantly lower than observed with control dung. The adult emergence rates of O. bivertex and O. lenzii were significantly reduced in dung collected at 1 to 3 and 1 to 7 days post-treatment, respectively. In P. auratus, there were no effects of ivermectin on adult survival, oviposition, feeding activity, or larval survival (until the third instar) in dung at 3 days post-treatment. The environmental risks affecting the populations of dung beetles in Japan are discussed.
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Affiliation(s)
- I Ishikawa
- Laboratory of Entomology, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan
| | - M Iwasa
- Laboratory of Entomology, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan
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13
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Charmpilas N, Ruckenstuhl C, Sica V, Büttner S, Habernig L, Dichtinger S, Madeo F, Tavernarakis N, Bravo-San Pedro JM, Kroemer G. Acyl-CoA-binding protein (ACBP): a phylogenetically conserved appetite stimulator. Cell Death Dis 2020; 11:7. [PMID: 31907349 PMCID: PMC6944704 DOI: 10.1038/s41419-019-2205-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 12/12/2019] [Accepted: 12/12/2019] [Indexed: 12/31/2022]
Abstract
Recently, we reported that, in mice, hunger causes the autophagy-dependent release of a protein called "acyl-CoA-binding protein" or "diazepam binding inhibitor" (ACBP/DBI) from cells, resulting in an increase in plasma ACBP concentrations. Administration of extra ACBP is orexigenic and obesogenic, while its neutralization is anorexigenic in mice, suggesting that ACBP is a major stimulator of appetite and lipo-anabolism. Accordingly, obese persons have higher circulating ACBP levels than lean individuals, and anorexia nervosa is associated with subnormal ACBP plasma concentrations. Here, we investigated whether ACBP might play a phylogenetically conserved role in appetite stimulation. We found that extracellular ACBP favors sporulation in Saccharomyces cerevisiae, knowing that sporulation is a strategy for yeast to seek new food sources. Moreover, in the nematode Caenorhabditis elegans, ACBP increased the ingestion of bacteria as well as the frequency pharyngeal pumping. These observations indicate that ACBP has a phylogenetically ancient role as a 'hunger factor' that favors food intake.
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Affiliation(s)
- Nikolaos Charmpilas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, Nikolaou Plastira 100, 70013, Heraklion, Crete, Greece
- Department of Biology, University of Crete, 70013, Heraklion, Crete, Greece
| | - Christoph Ruckenstuhl
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Humboldtstrasse 50, 8010, Graz, Austria
| | - Valentina Sica
- Metabolomics and Cell Biology Platforms, Gustave Roussy Cancer Campus, Villejuif, France
- Inserm U1138, Centre de Recherche des Cordeliers, Sorbonne Universite, Universite de Paris, 15-rue de l'ecole de medecine, 75006, Paris, France
- Team "Metabolism, Cancer & Immunity", equipe 11 labellisee par la Ligue contre le Cancer, Paris, France
| | - Sabrina Büttner
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Humboldtstrasse 50, 8010, Graz, Austria
- Department of Molecular Biosciences, The Wenner Gren Institute, Stockholm University, Stockholm, Sweden
| | - Lukas Habernig
- Department of Molecular Biosciences, The Wenner Gren Institute, Stockholm University, Stockholm, Sweden
| | - Silvia Dichtinger
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Humboldtstrasse 50, 8010, Graz, Austria
| | - Frank Madeo
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Humboldtstrasse 50, 8010, Graz, Austria.
- BioTechMed Graz, Graz, Austria.
| | - Nektarios Tavernarakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, Nikolaou Plastira 100, 70013, Heraklion, Crete, Greece.
- Department of Basic Sciences, Faculty of Medicine, University of Crete, 71110, Heraklion, Crete, Greece.
| | - José M Bravo-San Pedro
- Metabolomics and Cell Biology Platforms, Gustave Roussy Cancer Campus, Villejuif, France
- Inserm U1138, Centre de Recherche des Cordeliers, Sorbonne Universite, Universite de Paris, 15-rue de l'ecole de medecine, 75006, Paris, France
- Team "Metabolism, Cancer & Immunity", equipe 11 labellisee par la Ligue contre le Cancer, Paris, France
| | - Guido Kroemer
- Metabolomics and Cell Biology Platforms, Gustave Roussy Cancer Campus, Villejuif, France.
- Inserm U1138, Centre de Recherche des Cordeliers, Sorbonne Universite, Universite de Paris, 15-rue de l'ecole de medecine, 75006, Paris, France.
- Team "Metabolism, Cancer & Immunity", equipe 11 labellisee par la Ligue contre le Cancer, Paris, France.
- Pole de Biologie, Hopital Europeen Georges Pompidou, AP-HP, Paris, France.
- Suzhou Institute for Systems Medicine, Chinese Academy of Sciences, Suzhou, China.
- Karolinska Institute, Department of Women's and Children's Health, Karolinska University Hospital, Stockholm, Sweden.
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14
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Flatt KM, Beshers C, Unal C, Cohen JD, Sundaram MV, Schroeder NE. Epidermal Remodeling in Caenorhabditis elegans Dauers Requires the Nidogen Domain Protein DEX-1. Genetics 2019; 211:169-183. [PMID: 30409788 PMCID: PMC6325711 DOI: 10.1534/genetics.118.301557] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 10/29/2019] [Indexed: 01/23/2023] Open
Abstract
Phenotypic plasticity is a critical component of an organism's ability to thrive in a changing environment. The free-living nematode Caenorhabditis elegans adapts to unfavorable environmental conditions by pausing reproductive development and entering a stress-resistant larval stage known as dauer. The transition into dauer is marked by vast morphological changes, including remodeling of epidermis, neurons, and muscle. Although many of these dauer-specific traits have been described, the molecular basis of dauer-specific remodeling is still poorly understood. Here we show that the nidogen domain-containing protein DEX-1 facilitates stage-specific tissue remodeling during dauer morphogenesis. DEX-1 was previously shown to regulate sensory dendrite formation during embryogenesis. We find that DEX-1 is also required for proper remodeling of the stem cell-like epidermal seam cells. dex-1 mutant dauers lack distinct lateral cuticular alae during dauer and have increased sensitivity to sodium dodecyl sulfate. Furthermore, we find that DEX-1 is required for proper dauer mobility. We show that DEX-1 is secreted from the seam cells during dauer, but acts locally in a cell-autonomous manner. We find that dex-1 expression during dauer is regulated through DAF-16/FOXO-mediated transcriptional activation. Finally, we show that dex-1 acts with a family of zona pellucida domain-encoding genes to regulate dauer-specific epidermal remodeling. Taken together, our data indicate that DEX-1 is an extracellular matrix component that plays a central role in C. elegans epidermal remodeling during dauer.
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Affiliation(s)
- Kristen M Flatt
- Program in Neuroscience, University of Illinois at Urbana-Champaign, Illinois 61801-4730
| | - Caroline Beshers
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Illinois 61801-4730
| | - Cagla Unal
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Illinois 61801-4730
| | - Jennifer D Cohen
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104-6145
| | - Meera V Sundaram
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104-6145
| | - Nathan E Schroeder
- Program in Neuroscience, University of Illinois at Urbana-Champaign, Illinois 61801-4730
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Illinois 61801-4730
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15
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Webster AK, Jordan JM, Hibshman JD, Chitrakar R, Baugh LR. Transgenerational Effects of Extended Dauer Diapause on Starvation Survival and Gene Expression Plasticity in Caenorhabditis elegans. Genetics 2018; 210:263-274. [PMID: 30049782 PMCID: PMC6116965 DOI: 10.1534/genetics.118.301250] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 07/24/2018] [Indexed: 12/29/2022] Open
Abstract
Phenotypic plasticity is facilitated by epigenetic regulation, and remnants of such regulation may persist after plasticity-inducing cues are gone. However, the relationship between plasticity and transgenerational epigenetic memory is not understood. Dauer diapause in Caenorhabditis elegans provides an opportunity to determine how a plastic response to the early-life environment affects traits later in life and in subsequent generations. We report that, after extended diapause, postdauer worms initially exhibit reduced reproductive success and greater interindividual variation. In contrast, F3 progeny of postdauers display increased starvation resistance and lifespan, revealing potentially adaptive transgenerational effects. Transgenerational effects are dependent on the duration of diapause, indicating an effect of extended starvation. In agreement, RNA-seq demonstrates a transgenerational effect on nutrient-responsive genes. Further, postdauer F3 progeny exhibit reduced gene expression plasticity, suggesting a trade-off between plasticity and epigenetic memory. This work reveals complex effects of nutrient stress over different time scales in an animal that evolved to thrive in feast and famine.
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Affiliation(s)
- Amy K Webster
- Department of Biology, Duke University, Durham, North Carolina 27708
- University Program in Genetics and Genomics, Duke University, Durham, North Carolina 27708
| | - James M Jordan
- Department of Biology, Duke University, Durham, North Carolina 27708
| | - Jonathan D Hibshman
- Department of Biology, Duke University, Durham, North Carolina 27708
- University Program in Genetics and Genomics, Duke University, Durham, North Carolina 27708
| | - Rojin Chitrakar
- Department of Biology, Duke University, Durham, North Carolina 27708
| | - L Ryan Baugh
- Department of Biology, Duke University, Durham, North Carolina 27708
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16
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Fu J, Zhang H, Huang W, Zhu X, Sheng Y, Song E, Xu T. AIM interneurons mediate feeding suppression through the TYRA-2 receptor in C. elegans. BIOPHYSICS REPORTS 2018; 4:17-24. [PMID: 29577066 PMCID: PMC5860128 DOI: 10.1007/s41048-018-0046-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 05/23/2017] [Indexed: 12/02/2022] Open
Abstract
Feeding behavior is the most fundamental behavior in C. elegans. Our previous results have dissected the central integration circuit for the regulation of feeding, which integrates opposing sensory inputs and regulates feeding behavior in a nonlinear manner. However, the peripheral integration that acts downstream of the central integration circuit to modulate feeding remains largely unknown. Here, we find that a Gαi/o-coupled tyramine receptor, TYRA-2, is involved in peripheral feeding suppression. TYRA-2 suppresses feeding behavior via the AIM interneurons, which receive tyramine/octopamine signals from RIM/RIC neurons in the central integration circuit. Our results reveal previously unidentified roles for the receptor TYRA-2 and the AIM interneurons in feeding regulation, providing a further understanding of how biogenic amines tyramine and octopamine regulate feeding behavior.
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Affiliation(s)
- Jiajun Fu
- 1National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China.,2College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Haining Zhang
- 1National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China.,3Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074 China
| | - Wenming Huang
- 1National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China.,3Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074 China
| | - Xinyu Zhu
- 1National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China.,3Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074 China
| | - Yi Sheng
- 1National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China.,3Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074 China
| | - Eli Song
- 1National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China
| | - Tao Xu
- 1National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China.,2College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049 China.,3Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074 China
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17
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Optical silencing of body wall muscles induces pumping inhibition in Caenorhabditis elegans. PLoS Genet 2017; 13:e1007134. [PMID: 29281635 PMCID: PMC5760098 DOI: 10.1371/journal.pgen.1007134] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 01/09/2018] [Accepted: 11/28/2017] [Indexed: 01/08/2023] Open
Abstract
Feeding, a vital behavior in animals, is modulated depending on internal and external factors. In the nematode Caenorhabditis elegans, the feeding organ called the pharynx ingests food by pumping driven by the pharyngeal muscles. Here we report that optical silencing of the body wall muscles, which drive the locomotory movement of worms, affects pumping. In worms expressing the Arch proton pump or the ACR2 anion channel in the body wall muscle cells, the pumping rate decreases after activation of Arch or ACR2 with light illumination, and recovers gradually after terminating illumination. Pumping was similarly inhibited by illumination in locomotion-defective mutants carrying Arch, suggesting that perturbation of locomotory movement is not critical for pumping inhibition. Analysis of mutants and cell ablation experiments showed that the signals mediating the pumping inhibition response triggered by activation of Arch with weak light are transferred mainly through two pathways: one involving gap junction-dependent mechanisms through pharyngeal I1 neurons, which mediate fast signals, and the other involving dense-core vesicle-dependent mechanisms, which mediate slow signals. Activation of Arch with strong light inhibited pumping strongly in a manner that does not rely on either gap junction-dependent or dense-core vesicle-dependent mechanisms. Our study revealed a new aspect of the neural and neuroendocrine controls of pumping initiated from the body wall muscles. Since feeding is an essential behavior for the survival of animals, it is modulated by a variety of neural and neuroendocrine signals that are generated depending on internal and external conditions. To elucidate the cellular and molecular mechanisms underlying the regulation of feeding, the nematode Caenorhabditis elegans, which is composed of a small number of identifiable cells, provides a unique system. In C. elegans, the pumping movement of a feeding organ called the pharynx has been subjected to intensive genetic studies. Compared to the factors promoting pumping, however, the inhibitory mechanisms of pumping are less well understood. In this paper, we report that optogenetic silencing of the body wall muscles, which drive the locomotory movement of worms, inhibits pumping in the pharynx. Signals emanating from muscles are likely to trigger pumping inhibition, raising an interesting possibility that the proprioceptive sense detecting the relaxation of body wall muscles might be involved. When the Arch proton pump was activated with weak light, signals for pumping inhibition are transferred into the pharynx mainly through two pathways: one involving gap junction-dependent mechanisms through pharyngeal I1 neurons, which mediate fast signals, and the other involving dense-core vesicle-dependent mechanisms, which mediate slow signals. Strong activation of Arch inhibits pumping very strongly via other mechanisms. Thus, we have revealed a new link between pumping and the body wall muscles, and confirmed the important cooperation of neural and neuroendocrine circuits in the regulation of feeding behaviors.
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18
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Androwski RJ, Flatt KM, Schroeder NE. Phenotypic plasticity and remodeling in the stress-induced Caenorhabditis elegans dauer. WILEY INTERDISCIPLINARY REVIEWS. DEVELOPMENTAL BIOLOGY 2017; 6:10.1002/wdev.278. [PMID: 28544390 PMCID: PMC5626018 DOI: 10.1002/wdev.278] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Revised: 03/23/2017] [Accepted: 04/14/2017] [Indexed: 12/22/2022]
Abstract
Organisms are often capable of modifying their development to better suit their environment. Under adverse conditions, the nematode Caenorhabditis elegans develops into a stress-resistant alternative larval stage called dauer. The dauer stage is the primary survival stage for C. elegans in nature. Large-scale tissue remodeling during dauer conveys resistance to harsh environments. The environmental and genetic regulation of the decision to enter dauer has been extensively studied. However, less is known about the mechanisms regulating tissue remodeling. Changes to the cuticle and suppression of feeding in dauers lead to an increased resistance to external stressors. Meanwhile reproductive development arrests during dauer while preserving the ability to reproduce once favorable environmental conditions return. Dramatic remodeling of neurons, glia, and muscles during dauer likely facilitate dauer-specific behaviors. Dauer-specific pulsation of the excretory duct likely mediates a response to osmotic stress. The power of C. elegans genetics has uncovered some of the molecular pathways regulating dauer tissue remodeling. In addition to genes that regulate single remodeling events, several mutants result in pleiotropic defects in dauer remodeling. This review details the individual aspects of morphological changes that occur during dauer formation and discusses molecular mechanisms regulating these processes. The dauer stage provides us with an excellent model for understanding phenotypic plasticity and remodeling from the individual cell to an entire animal. WIREs Dev Biol 2017, 6:e278. doi: 10.1002/wdev.278 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Rebecca J Androwski
- Neuroscience Program, University of Illinois at Urbana-Champaign, Champaign, IL, USA
| | - Kristen M Flatt
- Neuroscience Program, University of Illinois at Urbana-Champaign, Champaign, IL, USA
| | - Nathan E Schroeder
- Neuroscience Program and Department of Crop Sciences, University of Illinois at Urbana-Champaign, Champaign, IL, USA
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19
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Ohno H, Yoshida M, Sato T, Kato J, Miyazato M, Kojima M, Ida T, Iino Y. Luqin-like RYamide peptides regulate food-evoked responses in C. elegans. eLife 2017; 6. [PMID: 28847365 PMCID: PMC5576490 DOI: 10.7554/elife.28877] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 08/08/2017] [Indexed: 12/25/2022] Open
Abstract
Peptide signaling controls many processes involving coordinated actions of multiple organs, such as hormone-mediated appetite regulation. However, the extent to which the mode of action of peptide signaling is conserved in different animals is largely unknown, because many peptides and receptors remain orphan and many undiscovered peptides still exist. Here, we identify two novel Caenorhabditis elegans neuropeptides, LURY-1-1 and LURY-1-2, as endogenous ligands for the neuropeptide receptor-22 (NPR-22). Both peptides derive from the same precursor that is orthologous to invertebrate luqin/arginine-tyrosine-NH2 (RYamide) proneuropeptides. LURY-1 peptides are secreted from two classes of pharyngeal neurons and control food-related processes: feeding, lifespan, egg-laying, and locomotory behavior. We propose that LURY-1 peptides transmit food signals to NPR-22 expressed in feeding pacemaker neurons and a serotonergic neuron. Our results identified a critical role for luqin-like RYamides in feeding-related processes and suggested that peptide-mediated negative feedback is important for satiety regulation in C. elegans.
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Affiliation(s)
- Hayao Ohno
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Morikatsu Yoshida
- Department of Biochemistry, National Cerebral and Cardiovascular Center Research Institute, Osaka, Japan
| | - Takahiro Sato
- Molecular Genetics, Institute of Life Sciences, Kurume University, Fukuoka, Japan
| | - Johji Kato
- Department of Bioactive Peptides, Frontier Science Research Center, University of Miyazaki, Miyazaki, Japan
| | - Mikiya Miyazato
- Department of Biochemistry, National Cerebral and Cardiovascular Center Research Institute, Osaka, Japan
| | - Masayasu Kojima
- Molecular Genetics, Institute of Life Sciences, Kurume University, Fukuoka, Japan
| | - Takanori Ida
- Department of Bioactive Peptides, Frontier Science Research Center, University of Miyazaki, Miyazaki, Japan.,Center for Animal Disease Control, University of Miyazaki, Miyazaki, Japan
| | - Yuichi Iino
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
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Zhuo W, Lu H, McGrath PT. Microfluidic platform with spatiotemporally controlled micro-environment for studying long-term C. elegans developmental arrests. LAB ON A CHIP 2017; 17:1826-1833. [PMID: 28466940 PMCID: PMC5521175 DOI: 10.1039/c6lc01573e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Animals' long-term survival is dependent on their ability to sense, filter and respond to their environment at multiple timescales. For example, during development, animals integrate environmental information, which can then modulate adult behavior and developmental trajectory. The neural and molecular mechanisms that underlie these changes are poorly understood. C. elegans is a powerful model organism to study such mechanisms; however, conventional plate-based culturing techniques are limited in their ability to consistently control and modulate an animal's environmental conditions. To address this need, we developed a microfluidics-based experimental platform capable of long-term culture of populations of developing C. elegans covering the L1 larval stage to adulthood, while achieving spatial consistency and temporal control of their environment. To prevent bacterial accumulation and maintain optimal flow characteristics and nutrient consistency over the operational period of over one hundred and fifty hours, several features of the microfluidic system and the peripheral equipment were optimized. By manipulating food and pheromone exposure over several days, we were able to demonstrate environmental-dependent changes to growth rate and entry to dauer, an alternative developmental state. We envision this system to be useful in studying the mechanisms underlying long timescale changes to behavior and development in response to environmental changes.
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Affiliation(s)
- Weipeng Zhuo
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332-0100
| | - Hang Lu
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332-0100
- The Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA
| | - Patrick T. McGrath
- The Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332
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Dallière N, Bhatla N, Luedtke Z, Ma DK, Woolman J, Walker RJ, Holden-Dye L, O'Connor V. Multiple excitatory and inhibitory neural signals converge to fine-tune Caenorhabditis elegans feeding to food availability. FASEB J 2015; 30:836-48. [PMID: 26514165 DOI: 10.1096/fj.15-279257] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 10/13/2015] [Indexed: 01/02/2023]
Abstract
How an animal matches feeding to food availability is a key question for energy homeostasis. We addressed this in the nematode Caenorhabditis elegans, which couples feeding to the presence of its food (bacteria) by regulating pharyngeal activity (pumping). We scored pumping in the presence of food and over an extended time course of food deprivation in wild-type and mutant worms to determine the neural substrates of adaptive behavior. Removal of food initially suppressed pumping but after 2 h this was accompanied by intermittent periods of high activity. We show pumping is fine-tuned by context-specific neural mechanisms and highlight a key role for inhibitory glutamatergic and excitatory cholinergic/peptidergic drives in the absence of food. Additionally, the synaptic protein UNC-31 [calcium-activated protein for secretion (CAPS)] acts through an inhibitory pathway not explained by previously identified contributions of UNC-31/CAPS to neuropeptide or glutamate transmission. Pumping was unaffected by laser ablation of connectivity between the pharyngeal and central nervous system indicating signals are either humoral or intrinsic to the enteric system. This framework in which control is mediated through finely tuned excitatory and inhibitory drives resonates with mammalian hypothalamic control of feeding and suggests that fundamental regulation of this basic animal behavior may be conserved through evolution from nematode to human.
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Affiliation(s)
- Nicolas Dallière
- *Centre for Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, Southampton, United Kingdom; and Howard Hughes Medical Institute and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Nikhil Bhatla
- *Centre for Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, Southampton, United Kingdom; and Howard Hughes Medical Institute and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Zara Luedtke
- *Centre for Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, Southampton, United Kingdom; and Howard Hughes Medical Institute and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Dengke K Ma
- *Centre for Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, Southampton, United Kingdom; and Howard Hughes Medical Institute and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Jonathan Woolman
- *Centre for Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, Southampton, United Kingdom; and Howard Hughes Medical Institute and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Robert J Walker
- *Centre for Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, Southampton, United Kingdom; and Howard Hughes Medical Institute and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Lindy Holden-Dye
- *Centre for Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, Southampton, United Kingdom; and Howard Hughes Medical Institute and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Vincent O'Connor
- *Centre for Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, Southampton, United Kingdom; and Howard Hughes Medical Institute and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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Abstract
The compact nervous system of Caenorhabditis elegans and its genetic tractability are features that make this organism highly suitable for investigating energy balance in an animal system. Here, we focus on molecular components and organizational principles emerging from the investigation of pathways that largely originate in the nervous system and regulate feeding behavior but also peripheral fat regulation through neuroendocrine signaling. We provide an overview of studies aimed at understanding how C. elegans integrate internal and external cues in feeding behavior. We highlight some of the similarities and differences in energy balance between C. elegans and mammals. We also provide our perspective on unresolved issues, both conceptual and technical, that we believe have hampered critical evaluation of findings relevant to fat regulation in C. elegans.
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Affiliation(s)
- George A Lemieux
- Department of Physiology, University of California, San Francisco, California 94158;
| | - Kaveh Ashrafi
- Department of Physiology, University of California, San Francisco, California 94158;
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Abstract
UNLABELLED Sensory inputs are integrated extensively before decision making, with altered multisensory integration being associated with disorders such as autism. We demonstrate that the two C. elegans AIB interneurons function as a biphasic switch, integrating antagonistic, tonic, and acute inputs from three distinct pairs of sensory neurons to modulate nociception. Off food, animals reverse away from a noxious stimulus. In contrast, on food or serotonin, AIB signaling is inhibited and, although animals initiate an aversive response more rapidly, they continue forward after the initial backward locomotion is complete. That is, animals continue to move forward and feed even when presented with a noxious repellant, with AIB inhibition decreasing the repellant concentration evoking a maximal response. These studies demonstrate that the AIBs serve as an integrating hub, receiving inputs from different sensory neurons to modulate locomotory decision making differentially, and highlight the utility of this model to analyze the complexities of multisensory integration. SIGNIFICANCE STATEMENT Dysfunctional sensory signaling and perception are associated with a number of disease states, including autism spectrum disorders, schizophrenia, and anxiety. We have used the C. elegans model to examine multisensory integration at the interneuron level to better understand the modulation of this complex, multicomponent process. C. elegans responds to a repulsive odorant by first backing up and then either continuing forward or turning and moving away from the odorant. This decision-making process is modulated extensively by the activity state of the two AIB interneurons, with the AIBs integrating an array of synergistic and antagonistic glutamatergic inputs, from sensory neurons responding directly to the odorant to others responding to a host of additional environmental variables to ultimately fine tune aversive behaviors.
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Wever CM, Farrington D, Dent JA. The Validation of Nematode-Specific Acetylcholine-Gated Chloride Channels as Potential Anthelmintic Drug Targets. PLoS One 2015; 10:e0138804. [PMID: 26393923 PMCID: PMC4578888 DOI: 10.1371/journal.pone.0138804] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 09/03/2015] [Indexed: 01/06/2023] Open
Abstract
New compounds are needed to treat parasitic nematode infections in humans, livestock and plants. Small molecule anthelmintics are the primary means of nematode parasite control in animals; however, widespread resistance to the currently available drug classes means control will be impossible without the introduction of new compounds. Adverse environmental effects associated with nematocides used to control plant parasitic species are also motivating the search for safer, more effective compounds. Discovery of new anthelmintic drugs in particular has been a serious challenge due to the difficulty of obtaining and culturing target parasites for high-throughput screens and the lack of functional genomic techniques to validate potential drug targets in these pathogens. We present here a novel strategy for target validation that employs the free-living nematode Caenorhabditis elegans to demonstrate the value of new ligand-gated ion channels as targets for anthelmintic discovery. Many successful anthelmintics, including ivermectin, levamisole and monepantel, are agonists of pentameric ligand-gated ion channels, suggesting that the unexploited pentameric ion channels encoded in parasite genomes may be suitable drug targets. We validated five members of the nematode-specific family of acetylcholine-gated chloride channels as targets of agonists with anthelmintic properties by ectopically expressing an ivermectin-gated chloride channel, AVR-15, in tissues that endogenously express the acetylcholine-gated chloride channels and using the effects of ivermectin to predict the effects of an acetylcholine-gated chloride channel agonist. In principle, our strategy can be applied to validate any ion channel as a putative anti-parasitic drug target.
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Affiliation(s)
- Claudia M. Wever
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | | | - Joseph A. Dent
- Department of Biology, McGill University, Montreal, Quebec, Canada
- * E-mail:
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Low doses of ivermectin cause sensory and locomotor disorders in dung beetles. Sci Rep 2015; 5:13912. [PMID: 26350768 PMCID: PMC4563563 DOI: 10.1038/srep13912] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 08/07/2015] [Indexed: 01/19/2023] Open
Abstract
Ivermectin is a veterinary pharmaceutical generally used to control the ecto- and endoparasites of livestock, but its use has resulted in adverse effects on coprophilous insects, causing population decline and biodiversity loss. There is currently no information regarding the direct effects of ivermectin on dung beetle physiology and behaviour. Here, based on electroantennography and spontaneous muscle force tests, we show sub-lethal disorders caused by ivermectin in sensory and locomotor systems of Scarabaeus cicatricosus, a key dung beetle species in Mediterranean ecosystems. Our findings show that ivermectin decreases the olfactory and locomotor capacity of dung beetles, preventing them from performing basic biological activities. These effects are observed at concentrations lower than those usually measured in the dung of treated livestock. Taking into account that ivermectin acts on both glutamate-gated and GABA-gated chloride ion channels of nerve and muscle cells, we predict that ivermectin’s effects at the physiological level could influence many members of the dung pat community. The results indicate that the decline of dung beetle populations could be related to the harmful effects of chemical contamination in the dung.
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Neuronal serotonin release triggers the heat shock response in C. elegans in the absence of temperature increase. Curr Biol 2014; 25:163-174. [PMID: 25557666 DOI: 10.1016/j.cub.2014.11.040] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 10/13/2014] [Accepted: 11/17/2014] [Indexed: 01/07/2023]
Abstract
BACKGROUND Cellular mechanisms aimed at repairing protein damage and maintaining homeostasis, widely understood to be triggered by the damage itself, have recently been shown to be under cell nonautonomous control in the metazoan C. elegans. The heat shock response (HSR) is one such conserved mechanism, activated by cells upon exposure to proteotoxic conditions such as heat. Previously, we had shown that this conserved cytoprotective response is regulated by the thermosensory neuronal circuitry of C. elegans. Here, we investigate the mechanisms and physiological relevance of neuronal control. RESULTS By combining optogenetic methods with live visualization of the dynamics of the heat shock transcription factor (HSF1), we show that excitation of the AFD thermosensory neurons is sufficient to activate HSF1 in another cell, even in the absence of temperature increase. Excitation of the AFD thermosensory neurons enhances serotonin release. Serotonin release elicited by direct optogenetic stimulation of serotonergic neurons activates HSF1 and upregulates molecular chaperones through the metabotropic serotonin receptor SER-1. Consequently, excitation of serotonergic neurons alone can suppress protein misfolding in C. elegans peripheral tissue. CONCLUSIONS These studies imply that thermosensory activity coupled to serotonergic signaling is sufficient to activate the protective HSR prior to frank proteotoxic damage. The ability of neurosensory release of serotonin to control cellular stress responses and activate HSF1 has powerful implications for the treatment of protein conformation diseases.
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Kong C, Tan MW, Nathan S. Orthosiphon stamineus protects Caenorhabditis elegans against Staphylococcus aureus infection through immunomodulation. Biol Open 2014; 3:644-55. [PMID: 24972867 PMCID: PMC4154301 DOI: 10.1242/bio.20148334] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Amidst growing concerns over the spread of antibiotic-resistant Staphylococcus aureus strains, the identification of alternative therapeutic molecules has become paramount. Previously, we utilized a Caenorhabditis elegans–S. aureus screening platform to identify potential anti-infective agents from a collection of natural extracts and synthetic compounds. One of the hits obtained from the screen was the aqueous extract of Orthosiphon stamineus leaves (UE-12) that enhanced the survival of infected nematodes without interfering with bacterial growth. In this study, we used a fluorescent transgenic reporter strain and observed that the repressed expression of the lys-7 defense gene in infected nematodes was restored in the presence of UE-12. Analysis of a selected panel of PMK-1 and DAF-16-regulated transcripts and loss-of-function mutants in these pathways indicates that the protective role of UE-12 is mediated via the p38 MAP kinase and insulin-like signaling pathways. Further analysis of a panel of known bioactive compounds of UE-12 proposed eupatorin (C18H16O7) as the possible candidate active molecule contributing to the anti-infective property of UE-12. Taken together, these findings strongly suggest that the O. stamineus leaf extract is a promising anti-infective agent that confers an advantage in survival against S. aureus infection by modulating the immune response of the infected host.
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Affiliation(s)
- Cin Kong
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, 43600 UKM Bangi, Selangor, Malaysia
| | - Man-Wah Tan
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305-5120, USA Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305-5124, USA Present address: Department of Infectious Disease, Genentech, Inc., South San Francisco, CA 94080, USA
| | - Sheila Nathan
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, 43600 UKM Bangi, Selangor, Malaysia
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Bumbarger DJ, Riebesell M, Rödelsperger C, Sommer RJ. System-wide rewiring underlies behavioral differences in predatory and bacterial-feeding nematodes. Cell 2013; 152:109-19. [PMID: 23332749 DOI: 10.1016/j.cell.2012.12.013] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 10/26/2012] [Accepted: 12/07/2012] [Indexed: 10/27/2022]
Abstract
The relationship between neural circuit function and patterns of synaptic connectivity is poorly understood, in part due to a lack of comparative data for larger complete systems. We compare system-wide maps of synaptic connectivity generated from serial transmission electron microscopy for the pharyngeal nervous systems of two nematodes with divergent feeding behavior: the microbivore Caenorhabditis elegans and the predatory nematode Pristionchus pacificus. We uncover a massive rewiring in a complex system of identified neurons, all of which are homologous based on neurite anatomy and cell body position. Comparative graph theoretical analysis reveals a striking pattern of neuronal wiring with increased connectional complexity in the anterior pharynx correlating with tooth-like denticles, a morphological feature in the mouth of P. pacificus. We apply focused centrality methods to identify neurons I1 and I2 as candidates for regulating predatory feeding and predict substantial divergence in the function of pharyngeal glands.
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Affiliation(s)
- Daniel J Bumbarger
- Department for Evolutionary Biology, Max-Planck-Institute for Developmental Biology, Spemannstrasse 37, 72076 Tübingen, Germany
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Kim E, Sun L, Gabel CV, Fang-Yen C. Long-term imaging of Caenorhabditis elegans using nanoparticle-mediated immobilization. PLoS One 2013; 8:e53419. [PMID: 23301069 PMCID: PMC3536676 DOI: 10.1371/journal.pone.0053419] [Citation(s) in RCA: 160] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Accepted: 11/27/2012] [Indexed: 12/28/2022] Open
Abstract
One advantage of the nematode Caenorhabditis elegans as a model organism is its suitability for in vivo optical microscopy. Imaging C. elegans often requires animals to be immobilized to avoid movement-related artifacts. Immobilization has been performed by application of anesthetics or by introducing physical constraints using glue or specialized microfluidic devices. Here we present a method for immobilizing C. elegans using polystyrene nanoparticles and agarose pads. Our technique is technically simple, does not expose the worm to toxic substances, and allows recovery of animals. We evaluate the method and show that the polystyrene beads increase friction between the worm and agarose pad. We use our method to quantify calcium transients and long-term regrowth in single neurons following axotomy by a femtosecond laser.
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Affiliation(s)
- Eric Kim
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Lin Sun
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Christopher V. Gabel
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Christopher Fang-Yen
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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30
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Abstract
Glutamate-gated chloride channels (GluCls) are found only in protostome invertebrate phyla but are closely related to mammalian glycine receptors. They have a number of roles in these animals, controlling locomotion and feeding and mediating sensory inputs into behavior. In nematodes and arthropods, they are targeted by the macrocyclic lactone family of anthelmintics and pesticides, making the GluCls of considerable medical and economic importance. Recently, the three-dimensional structure of a GluCl was solved, the first for any eukaryotic ligand-gated anion channel, revealing a macrocyclic lactone-binding site between the channel domains of adjacent subunits. This minireview will highlight some unique features of the GluCls and illustrate their contribution to our knowledge of the entire Cys loop ligand-gated ion channel superfamily.
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Dharmalingam K, Tan BK, Mahmud MZ, Sedek SAM, Majid MIA, Kuah MK, Sulaiman SF, Ooi KL, Khan NAK, Muhammad TST, Tan MW, Shu-Chien AC. Swietenia macrophylla extract promotes the ability of Caenorhabditis elegans to survive Pseudomonas aeruginosa infection. JOURNAL OF ETHNOPHARMACOLOGY 2012; 139:657-663. [PMID: 22193176 DOI: 10.1016/j.jep.2011.12.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 11/01/2011] [Accepted: 12/05/2011] [Indexed: 05/31/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Swietenia macrophylla or commonly known as big leaf mahogany, has been traditionally used as an antibacterial and antifungal agent. AIM OF THE STUDY The unwanted problem of antibiotic resistance in many bacterial species advocates the need for the discovery of the new anti-infective drugs. Here, we investigated the anti-infective properties of Swietenia macrophylla with an assay involving lethal infection of Caenorhabditis elegans with the opportunistic human pathogen Pseudomonas aeruginosa. MATERIALS AND METHODS Using a slow killing assay, Caenorhabditis elegans was challenged with an infective strain of Pseudomonas aeruginosa (PA14). The ability of Swietenia macrophylla seed ethyl acetate extract to promote the survival of infected worms was assessed by comparing the percentage of survival between extract treated and non-treated worm populations. The effect of Swietenia macrophylla towards PA14 growth, Caenorhabditis elegans feeding rate and degree of PA14 colonization in the worm gut was also evaluated. Lastly, using a fluorescent transgenic Caenorhabditis elegans strain and real time PCR, the effect of Swietenia macrophylla on the expression of lys-7, an immune response gene was also investigated. RESULTS Our results demonstrate the ability of Swietenia macrophylla seed ethyl acetate extract in rescuing Caenorhabditis elegans from fatal PA14 infection. Consequently, we showed that the extract promotes the survival without exhibiting any bactericidal effect or perturbation of Caenorhabditis elegans feeding rate. We also showed that Swietenia macrophylla was able to restore the initially repressed lys-7 level in PA14 infected Caenorhabditis elegans. CONCLUSION Swietenia macrophylla extract is able to enhance the ability of Caenorhabditis elegans to survive PA14 infection without directly killing the pathogen. We further showed that the extract boosted the expression of a gene pivotal for innate immunity in Caenorhabditis elegans. Collectively, these findings strongly suggest the presence of compounds within Swietenia macrophylla seed that either reduces Pseudomonas aeruginosa virulence and/or enhance host resistance.
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Affiliation(s)
- Komalavali Dharmalingam
- Malaysian Institute of Pharmaceuticals and Nutraceuticals, Ministry of Science, Technology and Innovation, Penang, Malaysia
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Reimschuessel R, Gieseker C, Poynton S. In vitro effect of seven antiparasitics on Acolpenteron ureteroecetes (Dactylogyridae) from largemouth bass Micropterus salmoides (Centrarchidae). DISEASES OF AQUATIC ORGANISMS 2011; 94:59-72. [PMID: 21553568 DOI: 10.3354/dao02303] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Few drugs are approved by the United States Food and Drug Administration for treating parasite infections in minor species such as fish, due in part to the high cost of developing such drugs and to a relatively small market share for drug sponsors. Because in vivo effectiveness trials for antiparasitic drugs are costly, time consuming, and use many animals, a systematic in vitro screening approach to describe parasite motility could help find promising drug candidates. We evaluated the effects of 7 antiparasitics on the activity and survival of the endoparasitic monogenean Acolpenteron ureteroecetes (Dactylogyridae) collected from the posterior kidneys of juvenile largemouth bass Micropterus salmoides (Lacepede, 1802) (Centrarchidae) held in the laboratory. Tests were conducted in 12 well tissue culture plates; each well had 3 parasites, and we tested 3 concentrations and 1 control for each of the 7 antiparasitics. The parasites were observed immediately after adding the drug, at 1 to 3 h, and 17 to 26 h, and video recordings were made. Drug effects were recorded by documenting morbidity (reduced movement, tremors, contracted body, abnormal morphology) and mortality. A. ureteroecetes was strongly affected by the quinoline praziquantel, the imidazothiazide levamisole, and the organophosphates dichlorvos and trichlorfon. The parasites were moderately affected by the macrocyclic lactones ivermectin and emamectin, and generally unaffected by the benzimidazole mebendazole. Our study demonstrates the utility of characterizing in vitro responses with video microscopy to document responses of fish parasites for initial screens of drug effects on a fish monogenean.
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Affiliation(s)
- Renate Reimschuessel
- US Food and Drug Administration, Center for Veterinary Medicine, Office of Research, 8401 Muirkirk Road, Laurel, Maryland 20708, USA
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Pharmacogenetic analysis reveals a post-developmental role for Rac GTPases in Caenorhabditis elegans GABAergic neurotransmission. Genetics 2009; 183:1357-72. [PMID: 19797046 DOI: 10.1534/genetics.109.106880] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The nerve-cell cytoskeleton is essential for the regulation of intrinsic neuronal activity. For example, neuronal migration defects are associated with microtubule regulators, such as LIS1 and dynein, as well as with actin regulators, including Rac GTPases and integrins, and have been thought to underlie epileptic seizures in patients with cortical malformations. However, it is plausible that post-developmental functions of specific cytoskeletal regulators contribute to the more transient nature of aberrant neuronal activity and could be masked by developmental anomalies. Accordingly, our previous results have illuminated functional roles, distinct from developmental contributions, for Caenorhabditis elegans orthologs of LIS1 and dynein in GABAergic synaptic vesicle transport. Here, we report that C. elegans with function-altering mutations in canonical Rac GTPase-signaling-pathway members demonstrated a robust behavioral response to a GABA(A) receptor antagonist, pentylenetetrazole. Rac mutants also exhibited hypersensitivity to an acetylcholinesterase inhibitor, aldicarb, uncovering deficiencies in inhibitory neurotransmission. RNA interference targeting Rac hypomorphs revealed synergistic interactions between the dynein motor complex and some, but not all, members of Rac-signaling pathways. These genetic interactions are consistent with putative Rac-dependent regulation of actin and microtubule networks and suggest that some cytoskeletal regulators cooperate to uniquely govern neuronal synchrony through dynein-mediated GABAergic vesicle transport in C. elegans.
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Ardelli BF, Stitt LE, Tompkins JB, Prichard RK. A comparison of the effects of ivermectin and moxidectin on the nematode Caenorhabditis elegans. Vet Parasitol 2009; 165:96-108. [PMID: 19631471 DOI: 10.1016/j.vetpar.2009.06.043] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2008] [Revised: 04/28/2009] [Accepted: 06/22/2009] [Indexed: 11/25/2022]
Abstract
The avermectins and the milbemycins are structurally related classes of 16-membered macrocyclic lactones (ML) that have a broad spectrum of activity. Most studies on the mode of action of ML have used the avermectin, ivermectin (IVM). IVM activates glutamate-gated chloride channels that contain alpha-type subunits, resulting in a hyperpolarization of the neuronal membrane, leading to a flaccid paralysis. IVM kills Caenorhabditis elegans at therapeutic concentrations, making it a useful model to examine mechanisms of IVM toxicity and resistance. There have been suggestions that the milbemycins may exert effects that are different from the avermectins, however this hypothesis has been challenged. Using IVM and the milbemycin, moxidectin (MOX), we demonstrate that while the two drugs have some similar effects on C. elegans, there are also some differences in worm response. Following exogenous exposure to a gradient of IVM and MOX, ranging from 0 to 5000 nM, quantitative and qualitative differences in response to the two anthelmintic drugs were observed in the pharyngeal pump rate, larval development and motility of wild-type and glutamate-gated chloride channel (GluCl) subunit knockout strains of C. elegans. After exposure to equimolar drug concentrations, differences between the anthelmintic effects were observed in the motility phenotype in the wild-type, GluCl subunit knockout strains and multi-gene knockout strain of C. elegans that exhibits a marked reduction in IVM sensitivity; and transcription profiles of genes coding for GluCl subunits in both the wild-type and glc-2 knockout strain. The glc-2 deletion strain showed increased motility in response to 2.5nM MOX in the first 1.5h of exposure, compared with wild-type nematodes, whereas this strain showed little change in motility in response to IVM. The pharyngeal pump rate in the glc-2 deletion strain was sensitive to equimolar concentrations of IVM and MOX. The triple avr-14/avr-15/glc-1 knockout caused a loss of initial stimulation of motility seen in the wild-type, by 2.5 nM IVM, to a reduction in motility, whereas the response to MOX was little changed between this triple knockout strain and wild-type C. elegans. The results suggest that there are significant differences in the response of C. elegans to IVM and MOX. The product of the glc-2 gene may play a role in sensitivity to MOX, but not to IVM, while the products of avr-14, avr-15 and glc-1 may be important for the effects of IVM, but less so for MOX.
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Affiliation(s)
- Bernadette F Ardelli
- Department of Biology, Brandon University, 270-18th St., Brandon, Manitoba, Canada.
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35
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Janssen T, Husson SJ, Lindemans M, Mertens I, Rademakers S, Ver Donck K, Geysen J, Jansen G, Schoofs L. Functional characterization of three G protein-coupled receptors for pigment dispersing factors in Caenorhabditis elegans. J Biol Chem 2008; 283:15241-9. [PMID: 18390545 DOI: 10.1074/jbc.m709060200] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Here, we report the identification, cloning, and functional characterization of three Caenorhabditis elegans G protein-coupled pigment dispersing factor (PDF) receptors, which we designated as Ce_PDFR-1a, -b, and -c. They represent three splice isoforms of the same gene (C13B9.4), which share a high degree of similarity with the Drosophila PDF receptor and are distantly related to the mammalian vasoactive intestinal peptide receptors (VPAC2) and calcitonin receptors. In a reverse pharmacological screen, three bioactive C. elegans neuropeptides, which were recently identified as the Drosophila PDF orthologues, were able to activate these receptors in a dose-dependent manner with nanomolar potency (isoforms a and b). Integrated green fluorescent protein reporter constructs reveal the expression of these PDF receptors in all body wall muscle cells and many head and tail neurons involved in the integration of environmental stimuli and the control of locomotion. Using a custom data analysis system, we demonstrate the involvement of this newly discovered neuropeptide signaling system in the regulation of locomotor behavior. Overexpression of PDF-2 phenocopies the locomotor defects of a PDF-1 null mutant, suggesting that they elicit opposite effects on locomotion through the identified PDF receptors. Our findings strengthen the hypothesis that the PDF signaling system, which imposes the circadian clock rhythm on behavior in Drosophila, has been functionally conserved throughout the protostomian evolutionary lineage.
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Affiliation(s)
- Tom Janssen
- Functional Genomics and Proteomics Unit, Department of Biology, K.U. Leuven, Naamsestraat 59, Leuven, Belgium.
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36
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Van Buskirk C, Sternberg PW. Epidermal growth factor signaling induces behavioral quiescence in Caenorhabditis elegans. Nat Neurosci 2007; 10:1300-7. [PMID: 17891142 DOI: 10.1038/nn1981] [Citation(s) in RCA: 164] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2007] [Accepted: 08/17/2007] [Indexed: 01/12/2023]
Abstract
The epidermal growth factor receptor (EGFR)/ErbB receptor tyrosine kinases regulate several aspects of development, including the development of the mammalian nervous system. ErbB signaling also has physiological effects on neuronal function, with influences on synaptic plasticity and daily cycles of activity. However, little is known about the effectors of EGFR activation in neurons. Here we show that EGF signaling has a nondevelopmental effect on behavior in Caenorhabditis elegans. Ectopic expression of the EGF-like ligand LIN-3 at any stage induces a reversible cessation of feeding and locomotion. These effects are mediated by neuronal EGFR (also called LET-23) and phospholipase C-gamma (PLC-gamma), diacylglycerol-binding proteins, and regulators of synaptic vesicle release. Activation of EGFR within a single neuron, ALA, is sufficient to induce a quiescent state. This pathway modulates the cessation of pharyngeal pumping and locomotion that normally occurs during the lethargus period that precedes larval molting. Our results reveal an evolutionarily conserved role for EGF signaling in the regulation of behavioral quiescence.
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Affiliation(s)
- Cheryl Van Buskirk
- Howard Hughes Medical Institute, Division of Biology 156-29, California Institute of Technology, 1200 E. California Blvd. Pasadena, California 91125, USA
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Franks CJ, Holden-Dye L, Bull K, Luedtke S, Walker RJ. Anatomy, physiology and pharmacology of Caenorhabditis elegans pharynx: a model to define gene function in a simple neural system. INVERTEBRATE NEUROSCIENCE 2006; 6:105-22. [PMID: 16862440 DOI: 10.1007/s10158-006-0023-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Accepted: 06/26/2006] [Indexed: 12/31/2022]
Abstract
Invertebrate neuroscience has provided a number of very informative model systems that have been extensively utilized in order to define the neurobiological bases of animal behaviours (Sattelle and Buckingham in Invert Neurosci 6:1-3, 2006). Most eminent among these are a number of molluscs, including Aplysia californica, Lymnaea stagnalis and Helix aspersa, crustacean systems such as the crab stomatogastric ganglion and a wide-range of other arthropods. All of these have been elegantly exploited to shed light on the very important phenomenon of the molecular and cellular basis for synaptic regulation that underpins behavioural plasticity. Key to the successful use of these systems has been the ability to study well-defined, relatively simple neuronal circuits that direct and regulate a quantifiable animal behaviour. Here we describe the pharyngeal system of the nematode C. elegans and its utility as a model for defining the genetic basis of behaviour. The circuitry of the nervous system in this animal is uniquely well-defined. Furthermore, the feeding behaviour of the worm is controlled by the activity of the pharynx and this in turn is regulated in a context-dependent manner by a simple nervous system that integrates external signals, e.g. presence or absence of food, and internal signals, e.g. the nutritional status of the animal to direct an appropriate response. The genetics of C. elegans is being effectively exploited to provide novel insight into genes that function to regulate the neuronal network that controls the pharynx. Here we summarise the progress to date and highlight topics for future research. Two main themes emerge. First, although the anatomy of the pharyngeal system is very well-defined, there is a much poorer understanding of its neurochemistry. Second, it is evident that the neurochemistry is remarkably complex for such a simple circuit/behaviour. This suggests that the pharyngeal activity may be subject to exquisitely precise regulation depending on the animal's environment and status. This therefore provides a very tractable genetic model to investigate neural mechanisms for signal integration and synaptic plasticity in a well-defined neuronal network that directs a quantifiable behaviour, feeding.
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Affiliation(s)
- Christopher J Franks
- School of Biological Sciences, Bassett Crescent East, University of Southampton, Southampton, SO16 7PX, UK
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38
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Wolstenholme AJ, Rogers AT. Glutamate-gated chloride channels and the mode of action of the avermectin/milbemycin anthelmintics. Parasitology 2006; 131 Suppl:S85-95. [PMID: 16569295 DOI: 10.1017/s0031182005008218] [Citation(s) in RCA: 216] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The macrocyclic lactones are the biggest selling and arguably most effective anthelmintics currently available. They are good substrates for the P-glycoproteins, which might explain their selective toxicity for parasites over their vertebrate hosts. Changes in the expression of these pumps have been implicated in resistance to the macrocyclic lactones, but it is clear that they exert their anthelmintic effects by binding to glutamate-gated chloride channels expressed on nematode neurones and pharyngeal muscle cells. This effect is quite distinct from the channel opening induced by glutamate, the endogenous transmitter acting at these receptors, which produces rapidly opening and desensitising channels. Ivermectin-activated channels open very slowly but essentially irreversibly, leading to a very long-lasting hyperpolarisation or depolarisation of the neurone or muscle cell and therefore blocking further function. Molecular and genetic studies have shown that there are multiple GluCl isoforms in both free-living and parasitic nematodes: the exact genetic make-up and functions of the GluCl may vary between species. The known expression patterns of the GluCl explain most of the observed biological effects of treatment with the macrocyclic lactones, though the reason for the long-lasting inhibition of larval production in filarial species is still poorly understood.
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Affiliation(s)
- A J Wolstenholme
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK.
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Liu HP, Lin SC, Lin CY, Yeh SR, Chiang AS. Glutamate-gated chloride channels inhibit juvenile hormone biosynthesis in the cockroach, Diploptera punctata. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2005; 35:1260-8. [PMID: 16203207 DOI: 10.1016/j.ibmb.2005.06.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2005] [Revised: 06/27/2005] [Accepted: 06/30/2005] [Indexed: 05/04/2023]
Abstract
Juvenile hormone (JH) synthesized and released from endocrine gland corpus allatum (CA) plays an important role in insect metamorphosis, vitellogenesis and reproduction. Glutamate is a major neurotransmitter in the nervous system and its activated receptors possess excitatory and inhibitory forms in muscle fibers of invertebrates. Previously, we have shown that the rise of intracellular calcium through excitatory glutamate receptors, N-methyl-d-aspartate (NMDA) and non-NMDA-type channels stimulates JH synthesis in the cockroach, Diploptera punctata. Here, we demonstrate the occurrence of inhibitory chloride permeable glutamate (GluCl) receptors on CA cell membranes. Application of the GluCl channel activators, ibotenic acid (Ibo) and ivermectin, but not gamma-aminobutyric acid caused a decline in JH synthesis in glands of either high or low activity during the gonadotrophic cycle. Also, while recording the membrane potential of the isolated whole CA glands intracellularly, Ibo induced a hyperpolarizated response. Both changes in the membrane potential and inhibition of JH synthesis could be abolished by the application of the chloride channel blocker picrotoxin. Finally, we found both excitatory and inhibitory glutamate receptors cause antagonistic effects on rates of JH synthesis. These results indicate a novel function of GluCl channels in the inhibition of JH synthesis that could be a potential pathway for developing a new generation of insecticides.
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Affiliation(s)
- Hsin-Ping Liu
- Institute of Biotechnology, National Tsing-Hua University, Hsinchu 300, Taiwan, ROC
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Shtonda B, Avery L. CCA-1, EGL-19 and EXP-2 currents shape action potentials in the Caenorhabditis elegans pharynx. ACTA ACUST UNITED AC 2005; 208:2177-90. [PMID: 15914661 PMCID: PMC1351090 DOI: 10.1242/jeb.01615] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The pharynx of Caenorhabditis elegans is a tubular muscle controlled by its own set of neurons. We developed a technique to voltage clamp the pharyngeal muscle and demonstrate by analyzing mutants that the pharyngeal action potential is regulated by three major voltage-gated currents, conducted by a T-type calcium channel CCA-1, an L-type calcium channel EGL-19 and a potassium channel EXP-2. We show that CCA-1 exhibits T-type calcium channel properties: activation at -40 mV and rapid inactivation. Our results suggest that CCA-1's role is to accelerate the action potential upstroke in the pharyngeal muscle in response to excitatory inputs. Similarly to other L-type channels, EGL-19 activates at high voltages and inactivates slowly; thus it may maintain the plateau phase of the action potential. EXP-2 is a potassium channel of the kV family that shows inward rectifier properties when expressed in Xenopus laevis oocytes. We show that endogenous EXP-2 is not a true inward rectifier--it conducts large outward currents at potentials up to +20 mV and is therefore well suited to trigger rapid repolarization at the end of the action potential plateau phase. Our results suggest that EXP-2 is a potassium channel with unusual properties that uses a hyperpolarization threshold to activate a regenerative hyperpolarizing current.
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Affiliation(s)
- Boris Shtonda
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, TX 75390-9148, USA.
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Phelan P. Innexins: members of an evolutionarily conserved family of gap-junction proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2004; 1711:225-45. [PMID: 15921654 DOI: 10.1016/j.bbamem.2004.10.004] [Citation(s) in RCA: 175] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 06/22/2004] [Revised: 10/12/2004] [Accepted: 10/14/2004] [Indexed: 11/20/2022]
Abstract
Gap junctions are clusters of intercellular channels that provide cells, in all metazoan organisms, with a means of communicating directly with their neighbours. Surprisingly, two gene families have evolved to fulfil this fundamental, and highly conserved, function. In vertebrates, gap junctions are assembled from a large family of connexin proteins. Innexins were originally characterized as the structural components of gap junctions in Drosophila, an arthropod, and the nematode Caenorhabditis elegans. Since then, innexin homologues have been identified in representatives of the other major invertebrate phyla and in insect-associated viruses. Intriguingly, functional innexin homologues have also been found in vertebrate genomes. These studies have informed our understanding of the molecular evolution of gap junctions and have greatly expanded the numbers of model systems available for functional studies. Genetic manipulation of innexin function in relatively simple cellular systems should speed progress not only in defining the importance of gap junctions in a variety of biological processes but also in elucidating the mechanisms by which they act.
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Affiliation(s)
- Pauline Phelan
- Department of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, UK.
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42
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Matyash V, Entchev EV, Mende F, Wilsch-Bräuninger M, Thiele C, Schmidt AW, Knölker HJ, Ward S, Kurzchalia TV. Sterol-derived hormone(s) controls entry into diapause in Caenorhabditis elegans by consecutive activation of DAF-12 and DAF-16. PLoS Biol 2004; 2:e280. [PMID: 15383841 PMCID: PMC517820 DOI: 10.1371/journal.pbio.0020280] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2004] [Accepted: 06/24/2004] [Indexed: 11/19/2022] Open
Abstract
Upon starvation or overcrowding, Caenorhabditis elegans interrupts its reproductive cycle and forms a specialised larva called dauer (enduring). This process is regulated by TGF-β and insulin-signalling pathways and is connected with the control of life span through the insulin pathway components DAF-2 and DAF-16. We found that replacing cholesterol with its methylated metabolite lophenol induced worms to form dauer larvae in the presence of food and low population density. Our data indicate that methylated sterols do not actively induce the dauer formation but rather that the reproductive growth requires a cholesterol-derived hormone that cannot be produced from methylated sterols. Using the effect of lophenol on growth, we have partially purified activity, named gamravali, which promotes the reproduction. In addition, the effect of lophenol allowed us to determine the role of sterols during dauer larva formation and longevity. In the absence of gamravali, the nuclear hormone receptor DAF-12 is activated and thereby initiates the dauer formation program. Active DAF-12 triggers in neurons the nuclear import of DAF-16, a forkhead domain transcription factor that contributes to dauer differentiation. This hormonal control of DAF-16 activation is, however, independent of insulin signalling and has no influence on life span. A sterol-derived activity is partially purified and shown to support reproductive growth under sterol-free conditions that normally induce dauer larva formation in nematodes
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Affiliation(s)
- Vitali Matyash
- 1Max Planck Institute for Molecular Cell Biology and GeneticsDresdenGermany
| | - Eugeni V Entchev
- 1Max Planck Institute for Molecular Cell Biology and GeneticsDresdenGermany
| | - Fanny Mende
- 1Max Planck Institute for Molecular Cell Biology and GeneticsDresdenGermany
| | | | - Christoph Thiele
- 1Max Planck Institute for Molecular Cell Biology and GeneticsDresdenGermany
| | - Arndt W Schmidt
- 2Institute of Organic Chemistry, Technical University of DresdenDresdenGermany
| | | | - Samuel Ward
- 3University of Arizona, TucsonArizonaUnited States of America
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Gardner MP, Gems D, Viney ME. Aging in a very short-lived nematode. Exp Gerontol 2004; 39:1267-76. [PMID: 15489049 DOI: 10.1016/j.exger.2004.06.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2004] [Revised: 06/17/2004] [Accepted: 06/18/2004] [Indexed: 11/23/2022]
Abstract
Aging has been characterised in detail in relatively few animal species. Here we describe the aging process in free-living adults of the parasitic nematode Strongyloides ratti. We find that the phenomenology of aging in S. ratti free-living females, resembles that of the short-lived free-living nematode Caenorhabditis elegans, except that it unfolds far more rapidly. The mean (3.0 +/- 0.1 days) and maximum (4.5 +/- 0.8 days) lifespans of free-living S. ratti females are approximately one quarter of equivalent values for C. elegans. Demographic senescence (a hallmark of aging) was observed in free-living S. ratti, with a mortality rate doubling time of 0.8 +/- 0.1 days (females), compared with 2.0 +/- 0.3 in C. elegans. S. ratti lifetime fertility and lifespan were affected by temperature, and there is an age-related decline in feeding rate and movement, similar to C. elegans, but occurring more quickly. Gut autofluorescence (lipofuscin) also increased with age in S. ratti free-living females, as in aging C. elegans. These findings show that the extreme brevity of life in free-living S. ratti adults, the shortest-lived nematode described to date, is the consequence of rapid aging, rather than some other, more rapid and catastrophic life-shortening pathology.
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Affiliation(s)
- Michael P Gardner
- School of Biological Sciences, University of Bristol, Woodland Road, Bristol, BS8 1UG, UK.
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