1
|
Marzec S, Siperstein A, Zhou A, Holzapfel CM, Bradshaw WE, Meuti ME, Armbruster PA. MicroRNA Expression Prior to Biting in a Vector Mosquito Anticipates Physiological Processes Related to Energy Utilization, Reproduction and Immunity. INSECTS 2023; 14:700. [PMID: 37623410 PMCID: PMC10455316 DOI: 10.3390/insects14080700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 07/30/2023] [Accepted: 08/08/2023] [Indexed: 08/26/2023]
Abstract
Understanding the molecular and physiological processes underlying biting behavior in vector mosquitoes has important implications for developing novel strategies to suppress disease transmission. Here, we conduct small-RNA sequencing and qRT-PCR to identify differentially expressed microRNAs (miRNAs) in the head tissues of two subspecies of Culex pipiens that differ in biting behavior and the ability to produce eggs without blood feeding. We identified eight differentially expressed miRNAs between biting C. pipiens pipiens (Pipiens) and non-biting C. pipiens molestus (Molestus); six of these miRNAs have validated functions or predicted targets related to energy utilization (miR8-5-p, miR-283, miR-2952-3p, miR-1891), reproduction (miR-1891), and immunity (miR-2934-3p, miR-92a, miR8-5-p). Although miRNAs regulating physiological processes associated with blood feeding have previously been shown to be differentially expressed in response to a blood meal, our results are the first to demonstrate differential miRNA expression in anticipation of a blood meal before blood is actually imbibed. We compare our current miRNA results to three previous studies of differential messenger RNA expression in the head tissues of mosquitoes. Taken together, the combined results consistently show that biting mosquitoes commit to specific physiological processes in anticipation of a blood meal, while non-biting mosquitoes mitigate these anticipatory costs.
Collapse
Affiliation(s)
- Sarah Marzec
- Department of Biology, Georgetown University, Washington, DC 20057, USA; (S.M.); (A.Z.)
| | - Alden Siperstein
- Department of Entomology, The Ohio State University, Columbus, OH 43210, USA; (A.S.); (M.E.M.)
| | - Angela Zhou
- Department of Biology, Georgetown University, Washington, DC 20057, USA; (S.M.); (A.Z.)
| | - Christina M. Holzapfel
- Laboratory of Evolutionary Genetics, Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA; (C.M.H.); (W.E.B.)
| | - William E. Bradshaw
- Laboratory of Evolutionary Genetics, Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA; (C.M.H.); (W.E.B.)
| | - Megan E. Meuti
- Department of Entomology, The Ohio State University, Columbus, OH 43210, USA; (A.S.); (M.E.M.)
| | - Peter A. Armbruster
- Department of Biology, Georgetown University, Washington, DC 20057, USA; (S.M.); (A.Z.)
| |
Collapse
|
2
|
Chotiwan N, Brito-Sierra CA, Ramirez G, Lian E, Grabowski JM, Graham B, Hill CA, Perera R. Expression of fatty acid synthase genes and their role in development and arboviral infection of Aedes aegypti. Parasit Vectors 2022; 15:233. [PMID: 35761349 PMCID: PMC9235097 DOI: 10.1186/s13071-022-05336-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 05/24/2022] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Fatty acids are the building blocks of complex lipids essential for living organisms. In mosquitoes, fatty acids are involved in cell membrane production, energy conservation and expenditure, innate immunity, development and reproduction. Fatty acids are synthesized by a multifunctional enzyme complex called fatty acid synthase (FAS). Several paralogues of FAS were found in the Aedes aegypti mosquito. However, the molecular characteristics and expression of some of these paralogues have not been investigated. METHODS Genome assemblies of Ae. aegypti were analyzed, and orthologues of human FAS was identified. Phylogenetic analysis and in silico molecular characterization were performed to identify the functional domains of the Ae. aegypti FAS (AaFAS). Quantitative analysis and loss-of-function experiments were performed to determine the significance of different AaFAS transcripts in various stages of development, expression following different diets and the impact of AaFAS on dengue virus, serotype 2 (DENV2) infection and transmission. RESULTS We identified seven putative FAS genes in the Ae. aegypti genome assembly, based on nucleotide similarity to the FAS proteins (tBLASTn) of humans, other mosquitoes and invertebrates. Bioinformatics and molecular analyses suggested that only five of the AaFAS genes produce mRNA and therefore represent complete gene models. Expression levels of AaFAS varied among developmental stages and between male and female Ae. aegypti. Quantitative analyses revealed that expression of AaFAS1, the putative orthologue of the human FAS, was highest in adult females. Transient knockdown (KD) of AaFAS1 did not induce a complete compensation by other AaFAS genes but limited DENV2 infection of Aag2 cells in culture and the midgut of the mosquito. CONCLUSION AaFAS1 is the predominant AaFAS in adult mosquitoes. It has the highest amino acid similarity to human FAS and contains all enzymatic domains typical of human FAS. AaFAS1 also facilitated DENV2 replication in both cell culture and in mosquito midguts. Our data suggest that AaFAS1 may play a role in transmission of dengue viruses and could represent a target for intervention strategies.
Collapse
Affiliation(s)
- Nunya Chotiwan
- grid.47894.360000 0004 1936 8083Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO USA ,grid.10223.320000 0004 1937 0490Present Address: Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Samut Prakan, Thailand
| | - Carlos A. Brito-Sierra
- grid.169077.e0000 0004 1937 2197Department of Entomology, Purdue University, West Lafayette, IL USA ,grid.169077.e0000 0004 1937 2197Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN USA ,grid.417540.30000 0000 2220 2544Present Address: Lilly Research Laboratories, Eli Lilly and Company, IN Indianapolis, USA
| | - Gabriella Ramirez
- grid.47894.360000 0004 1936 8083Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO USA
| | - Elena Lian
- grid.47894.360000 0004 1936 8083Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO USA
| | - Jeffrey M. Grabowski
- grid.169077.e0000 0004 1937 2197Department of Entomology, Purdue University, West Lafayette, IL USA ,grid.417439.c0000 0004 4665 2602Present Address: Foundation for Advanced Education in the Sciences at the NIH, Bethesda, MD USA
| | - Babara Graham
- grid.47894.360000 0004 1936 8083Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO USA
| | - Catherine A. Hill
- grid.169077.e0000 0004 1937 2197Department of Entomology, Purdue University, West Lafayette, IL USA ,grid.169077.e0000 0004 1937 2197Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN USA
| | - Rushika Perera
- grid.47894.360000 0004 1936 8083Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO USA
| |
Collapse
|
3
|
Schneider CA, Calvo E, Peterson KE. Arboviruses: How Saliva Impacts the Journey from Vector to Host. Int J Mol Sci 2021; 22:ijms22179173. [PMID: 34502092 PMCID: PMC8431069 DOI: 10.3390/ijms22179173] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 08/19/2021] [Accepted: 08/22/2021] [Indexed: 12/21/2022] Open
Abstract
Arthropod-borne viruses, referred to collectively as arboviruses, infect millions of people worldwide each year and have the potential to cause severe disease. They are predominately transmitted to humans through blood-feeding behavior of three main groups of biting arthropods: ticks, mosquitoes, and sandflies. The pathogens harbored by these blood-feeding arthropods (BFA) are transferred to animal hosts through deposition of virus-rich saliva into the skin. Sometimes these infections become systemic and can lead to neuro-invasion and life-threatening viral encephalitis. Factors intrinsic to the arboviral vectors can greatly influence the pathogenicity and virulence of infections, with mounting evidence that BFA saliva and salivary proteins can shift the trajectory of viral infection in the host. This review provides an overview of arbovirus infection and ways in which vectors influence viral pathogenesis. In particular, we focus on how saliva and salivary gland extracts from the three dominant arbovirus vectors impact the trajectory of the cellular immune response to arbovirus infection in the skin.
Collapse
Affiliation(s)
- Christine A. Schneider
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA;
| | - Eric Calvo
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA;
| | - Karin E. Peterson
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA;
- Correspondence:
| |
Collapse
|
4
|
Birungi K, Mabuka DP, Balyesima V, Namukwaya A, Chemoges EW, Kiwuwa-Muyingo S, Collins CM, Tripet F, Kayondo JK. Eave and swarm collections prove effective for biased captures of male Anopheles gambiae mosquitoes in Uganda. Parasit Vectors 2021; 14:281. [PMID: 34039430 PMCID: PMC8152359 DOI: 10.1186/s13071-021-04770-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 05/03/2021] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Traditional malaria vector sampling techniques bias collections towards female mosquitoes. Comprehensive understanding of vector dynamics requires balanced vector sampling of both males and females. Male mosquito sampling is also necessary for population size estimations by male-based mark-release-recapture (MRR) studies and for developing innovations in mosquito control, such as the male-targeted sterile insect technique and other genetic modification approaches. This study evaluated a range of collection methods which show promise in providing a more equal, or even male-biased, sex representation in the sample. RESULTS Swarms were found at all study sites and were more abundant and larger at the peak of the wet season. Swarm sampling caught the most males, but when man/hour effort was factored in, sampling of eaves by aspiration was the more efficient method and also provided a representative sample of females. Grass-roofed houses were the most productive for eave collections. Overall few mosquitoes were caught with artificial resting traps (clay pots and buckets), although these sampling methods performed better at the start of the wet season than at its peak, possibly because of changes in mosquito ecology and an increased availability of natural resting sites later in the season. Aspiration of bushes was more productive at the peak of the wet season than at the start. CONCLUSIONS The results of this study demonstrate that eave aspiration was an efficient and useful male mosquito collection method at the study sites and a potentially powerful aid for swarm location and MRR studies. The methods evaluated may together deliver more sex-balanced mosquito captures and can be used in various combinations depending on the aims and ecological parameters of a given study.
Collapse
Affiliation(s)
- Krystal Birungi
- Entomology Division, Uganda Virus Research Institute (UVRI), Plot 51-59, P.O. Box 49, Entebbe, Uganda
| | - Danspaid P. Mabuka
- Entomology Division, Uganda Virus Research Institute (UVRI), Plot 51-59, P.O. Box 49, Entebbe, Uganda
| | - Victor Balyesima
- Entomology Division, Uganda Virus Research Institute (UVRI), Plot 51-59, P.O. Box 49, Entebbe, Uganda
| | - Annet Namukwaya
- Entomology Division, Uganda Virus Research Institute (UVRI), Plot 51-59, P.O. Box 49, Entebbe, Uganda
| | - Elinor W. Chemoges
- Entomology Division, Uganda Virus Research Institute (UVRI), Plot 51-59, P.O. Box 49, Entebbe, Uganda
| | | | - C. Matilda Collins
- The Centre for Environmental Policy, Imperial College London, The Weeks Building, 16-18 Princes Gardens, London, SW7 1NE UK
| | - Frederic Tripet
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Staffordshire, ST5 5BG UK
| | - Jonathan K. Kayondo
- Entomology Division, Uganda Virus Research Institute (UVRI), Plot 51-59, P.O. Box 49, Entebbe, Uganda
| |
Collapse
|
5
|
Konopka JK, Task D, Afify A, Raji J, Deibel K, Maguire S, Lawrence R, Potter CJ. Olfaction in Anopheles mosquitoes. Chem Senses 2021; 46:6246230. [PMID: 33885760 DOI: 10.1093/chemse/bjab021] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
As vectors of disease, mosquitoes are a global threat to human health. The Anopheles mosquito is the deadliest mosquito species as the insect vector of the malaria-causing parasite, which kills hundreds of thousands every year. These mosquitoes are reliant on their sense of smell (olfaction) to guide most of their behaviors, and a better understanding of Anopheles olfaction identifies opportunities for reducing the spread of malaria. This review takes a detailed look at Anopheles olfaction. We explore a range of topics from chemosensory receptors, olfactory neurons, and sensory appendages to behaviors guided by olfaction (including host-seeking, foraging, oviposition, and mating), to vector management strategies that target mosquito olfaction. We identify many research areas that remain to be addressed.
Collapse
Affiliation(s)
- Joanna K Konopka
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 855 North Wolfe Street, 434 Rangos Building, Baltimore, 21205 MD, USA
| | - Darya Task
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 855 North Wolfe Street, 434 Rangos Building, Baltimore, 21205 MD, USA
| | - Ali Afify
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 855 North Wolfe Street, 434 Rangos Building, Baltimore, 21205 MD, USA
| | - Joshua Raji
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 855 North Wolfe Street, 434 Rangos Building, Baltimore, 21205 MD, USA
| | - Katelynn Deibel
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 855 North Wolfe Street, 434 Rangos Building, Baltimore, 21205 MD, USA
| | - Sarah Maguire
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 855 North Wolfe Street, 434 Rangos Building, Baltimore, 21205 MD, USA
| | - Randy Lawrence
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 855 North Wolfe Street, 434 Rangos Building, Baltimore, 21205 MD, USA
| | - Christopher J Potter
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 855 North Wolfe Street, 434 Rangos Building, Baltimore, 21205 MD, USA
| |
Collapse
|
6
|
Wheelwright M, Whittle CR, Riabinina O. Olfactory systems across mosquito species. Cell Tissue Res 2021; 383:75-90. [PMID: 33475852 PMCID: PMC7873006 DOI: 10.1007/s00441-020-03407-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 12/15/2020] [Indexed: 01/06/2023]
Abstract
There are 3559 species of mosquitoes in the world (Harbach 2018) but, so far, only a handful of them have been a focus of olfactory neuroscience and neurobiology research. Here we discuss mosquito olfactory anatomy and function and connect these to mosquito ecology. We highlight the least well-known and thus most interesting aspects of mosquito olfactory systems and discuss promising future directions. We hope this review will encourage the insect neuroscience community to work more broadly across mosquito species instead of focusing narrowly on the main disease vectors.
Collapse
Affiliation(s)
- Matthew Wheelwright
- Department of Biosciences, Durham University, Stockton Road, Durham, DH1 3LE, UK
| | - Catherine R Whittle
- Department of Biosciences, Durham University, Stockton Road, Durham, DH1 3LE, UK
| | - Olena Riabinina
- Department of Biosciences, Durham University, Stockton Road, Durham, DH1 3LE, UK.
| |
Collapse
|
7
|
Cerkvenik U, Dodou D, van Leeuwen JL, Gussekloo SWS. Functional principles of steerable multi-element probes in insects. Biol Rev Camb Philos Soc 2018; 94:555-574. [PMID: 30259619 PMCID: PMC7379267 DOI: 10.1111/brv.12467] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Revised: 08/24/2018] [Accepted: 08/30/2018] [Indexed: 12/22/2022]
Abstract
Hemipterans, mosquitoes, and parasitic wasps probe in a variety of substrates to find hosts for their larvae or food sources. Probes capable of sensing and precise steering enable insects to navigate through solid substrates without visual information and to reach targets that are hidden deep inside the substrate. The probes belong to non‐related taxa and originate from abdominal structures (wasps) or mouthparts (hemipterans and mosquitoes), but nevertheless share several morphological characteristics. Although the transport function clearly differs (egg laying and acquisition of liquid food), the functional demands on the mechanical behaviour of the probe within the substrate tend to be similar. The probe needs to be thin to limit substrate deformation, and long, in order to attain substantial path lengths or depths. We linked the morphology across taxa to the different functional requirements, to provide insights into the biology of probing insects and the evolution of their probes. Current knowledge of insect probes is spread over many taxa, which offers the possibility to derive general characteristics of insect probing. Buckling during initial puncturing is limited by external support mechanisms. The probe itself consist of multiple (3–6) parts capable of sliding along one another. This multi‐part construction presumably enables advancement and precise three‐dimensional steering of the probe through the substrate with very low net external pushing forces, preventing buckling during substrate penetration. From a mechanical viewpoint, a minimum of three elements is required for 3D steering and volumetric exploration, as realised in the ovipositors of wasps. More elements, such as in six‐element probes of mosquitoes, may enhance friction in soft substrates. Alternatively, additional elements can have functions other than ‘drilling’, such as saliva injection in mosquitoes. Despite the gross similarities, probes show differences in their cross sections, tip morphologies, relative lengths of their elements, and the shape of their interconnections. The hypothesis is that the probe morphology is influenced by the substrate properties, which are mostly unknown. Correlating the observed diversity to substrate‐specific functional demands is therefore currently impossible. We conclude that a multipart probe with sliding elements is highly effective for volumetric substrate probing. Shared functional demands have led to an evolutionary convergence of slender multi‐element probes in disparate insect taxa. To fully understand 3D probing, it is necessary to study the sensory and material properties, as well as the detailed kinematics and dynamics of the various probes in relation to the nature of the selective pressure originating from the species‐specific substrates. Such knowledge will deepen our understanding of probing mechanisms and may support the development of slender, bio‐inspired probes.
Collapse
Affiliation(s)
- Uroš Cerkvenik
- Experimental Zoology Group, Department of Animal Sciences, Wageningen University, De Elst 1, 6708 WD, Wageningen, The Netherlands
| | - Dimitra Dodou
- Department of Biomechanical Engineering, Delft University of Technology, Mekelweg 2, 2628 CD, Delft, The Netherlands
| | - Johan L van Leeuwen
- Experimental Zoology Group, Department of Animal Sciences, Wageningen University, De Elst 1, 6708 WD, Wageningen, The Netherlands
| | - Sander W S Gussekloo
- Experimental Zoology Group, Department of Animal Sciences, Wageningen University, De Elst 1, 6708 WD, Wageningen, The Netherlands
| |
Collapse
|
8
|
Abstract
The insect repellent N,N-diethyl-3-methylbenzamide (DEET), is a multimodal compound that acts as a spatial repellent as well as an irritant (contact repellent), thus being perceived by the insect’s olfactory and gustatory systems as an odorant and a tastant, respectively. Soon after DEET was developed, almost 6 decades ago, it was reported that it reduced mosquito feeding on blood mixed with this repellent. It is now known that the mosquito proboscis senses contact repellents with the tips (labella) of the labium, which remain in direct contact with the outer layers of the skin, while the stylets, including the feeding deterrent sensor (labrum), penetrate the skin. We designed a behavioral assay that allowed us to measure feeding deterrence without complications from contact or spatial repellency. Using the southern house mosquito, Culex quinquefasciatus, we demonstrate here that when DEET was mixed with blood and covered by Parafilm® layers, the mean number of landings and duration of contacts with surfaces covering blood mixed with DEET or blood plus solvent (dimethyl sulfoxide) did not differ significantly thus implying that DEET did not leak to the outer surface. The feeding times, however, were significantly different. When blood was mixed either with 0.1 or 1% DEET, female southern house mosquitoes spent significantly (P<0.0001) less time feeding than the time spent feeding on blood mixed only with the solvent. By contrast, significant differences in the mean times of feeding on blood containing 1% picaridin and blood plus solvent were significant at 5%, but not at 1% level. Like DEET, the contact repellent and insecticide, permethrin, caused a significant (P<0.0001) reduction in feeding time. We, therefore, concluded, that in this context, DEET, permethrin, and, to a lesser extent, picaridin, act as feeding deterrents.
Collapse
|
9
|
Ma G, Wu C. Microneedle, bio-microneedle and bio-inspired microneedle: A review. J Control Release 2017; 251:11-23. [DOI: 10.1016/j.jconrel.2017.02.011] [Citation(s) in RCA: 168] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 02/11/2017] [Accepted: 02/13/2017] [Indexed: 12/29/2022]
|
10
|
Nikbakhtzadeh MR, Buss GK, Leal WS. Toxic Effect of Blood Feeding in Male Mosquitoes. Front Physiol 2016; 7:4. [PMID: 26858651 PMCID: PMC4726748 DOI: 10.3389/fphys.2016.00004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 01/08/2016] [Indexed: 12/05/2022] Open
Abstract
Blood- and sugar feeding of female mosquitoes has been frequently observed in the laboratory and in the field, but only sugar feeding of males has been reported. Here, we describe for the first time that Culex quinquefasciatus males feed on blood as well. Blood feeding easily happened on a blood-soaked cotton roll and, to a lesser extent, through a thin artificial layer. Mating history of a male specimen does not affect his blood feeding behavior. Male mosquitoes feed on blood even when they have a readily available sugar source. Nevertheless, feeding on blood reduces the survival rate of males to just a few days, as compared to more than a month for mosquitoes fed only on sugar. Comparing survival of male mosquitoes fed on blood only, sugar only, and a combination of both clearly demonstrated that mortality is not affected by malnutrition (reduced sugar levels), but rather due to ingested blood. On average male mosquitoes ingested ca. 0.5 μl of blood, i.e., about 10% of the amount of blood ingested by an engorged female. Although this unexpected observation of blood feeding in the laboratory by male mosquitoes is interesting, structural impairment prevents male feeding on vertebrate blood. In agreement with the literature, male and female proboscises and stylets were in general of similar size, but male mandibles were significantly shorter than female counterparts, thus explaining their inability to pierce through skin layers.
Collapse
Affiliation(s)
| | - Garrison K Buss
- Department of Molecular and Cellular Biology, University of California-Davis Davis, CA, USA
| | - Walter S Leal
- Department of Molecular and Cellular Biology, University of California-Davis Davis, CA, USA
| |
Collapse
|
11
|
Choo YM, Buss GK, Tan K, Leal WS. Multitasking roles of mosquito labrum in oviposition and blood feeding. Front Physiol 2015; 6:306. [PMID: 26578978 PMCID: PMC4625056 DOI: 10.3389/fphys.2015.00306] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 10/12/2015] [Indexed: 12/23/2022] Open
Abstract
Reception of odorants by two main head appendages, antennae and maxillary palps, is essential for insects' survival and reproduction. There is growing evidence in the literature suggesting that the proboscis is also an olfactory appendage and its function as an additional "antenna" has been previously proposed. We surmised that movements of the labrum toward a blood vessel might be chemically oriented and, if so, there should be odorant receptors expressed in the labrum. To test this hypothesis, we first compared by quantitative PCR expression of odorant receptors (OR) from the Southern house mosquito, Culex quinquefasciatus in antennae and proboscis and, subsequently compared OR expression in various proboscis parts. Our data suggested that a receptor for the oviposition attractant, skatole, CquiOR21, was not expressed in proboscis, whereas a receptor for another oviposition attractant, 4EP (4-ethylphenol), CquiOR99, and a receptorf for the insect repellent DEET, CquiOR136, were expressed in the stylet of the proboscis, particularly in the tip of the labrum. In a dual-choice olfactometer, mosquitoes having the stylet coated with nail polish were attracted to 4EP in the same manner as the untreated mosquitoes. By contrast, in an oviposition assay, the stylet-treated mosquitoes did not discriminate 4EP from control oviposition cups, whereas the untreated mosquitoes (as well as mosquitoes having the labella coated) laid significantly more egg rafts in cups treated with 4EP. Ablation experiments confirmed that 4EP was sensed by the labrum where CquiOR99 is highly expressed. Stylet-coated, labella-coated, and untreated mosquitoes laid significantly more egg rafts in skatole-treated cups than in control cups. Likewise, coating of proboscis structures with nail polish had no effect on DEET-mediated oviposition deterrence. In a behavioral arena designed to mimic a human arm, mosquitoes showed significantly reduced probing time when blood was impregnated with 4EP, i.e., they engaged more rapidly in continuous blood feeding as compared to untreated blood. The time of engagement for feeding in skatole-containing blood vs. untreated blood did not differ significantly. Taken together, these data suggest that 4EP reception by the labrum is important not only for oviposition decisions, but also for reducing probing and initiation of blood feeding.
Collapse
Affiliation(s)
| | | | | | - Walter S. Leal
- Department of Molecular and Cellular Biology, University of California-DavisDavis, CA, USA
| |
Collapse
|
12
|
Ha YR, Oh SR, Seo ES, Kim BH, Lee DK, Lee SJ. Detection of heparin in the salivary gland and midgut of Aedes togoi. THE KOREAN JOURNAL OF PARASITOLOGY 2014; 52:183-8. [PMID: 24850962 PMCID: PMC4028456 DOI: 10.3347/kjp.2014.52.2.183] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 01/27/2014] [Accepted: 01/29/2014] [Indexed: 12/28/2022]
Abstract
Mosquitoes secrete saliva that contains biological substances, including anticoagulants that counteract a host's hemostatic response and prevent blood clotting during blood feeding. This study aimed to detect heparin, an anticoagulant in Aedes togoi using an immunohistochemical detection method, in the salivary canal, salivary gland, and midgut of male and female mosquitoes. Comparisons showed that female mosquitoes contained higher concentrations of heparin than male mosquitoes. On average, the level of heparin was higher in blood-fed female mosquitoes than in non-blood-fed female mosquitoes. Heparin concentrations were higher in the midgut than in the salivary gland. This indicates presence of heparin in tissues of A. togoi.
Collapse
Affiliation(s)
- Young-Ran Ha
- Division of Integrative Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - So-Ra Oh
- Center for Biofluid and Biomimic Research, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Eun-Seok Seo
- Division of Integrative Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Bo-Heum Kim
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Dong-Kyu Lee
- Department of Biology, Kosin University, Busan 606-701, Korea
| | - Sang-Joon Lee
- Division of Integrative Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang 790-784, Korea. ; Center for Biofluid and Biomimic Research, Pohang University of Science and Technology, Pohang 790-784, Korea. ; School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang 790-784, Korea
| |
Collapse
|