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Rowe TTC, Gutbrod MS, Matthews PGD. Discontinuous gas exchange in Madagascan hissing cockroaches is not a consequence of hysteresis around a fixed PCO2 threshold. J Exp Biol 2022; 225:273911. [PMID: 34989396 DOI: 10.1242/jeb.242860] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Accepted: 12/26/2021] [Indexed: 11/20/2022]
Abstract
It has been hypothesised that insects display discontinuous gas-exchange cycles (DGCs) due to hysteresis in their ventilatory control, where CO2-sensitive respiratory chemoreceptors respond to changes in hemolymph PCO2 only after some delay. If correct, DGCs would be a manifestation of an unstable feedback loop between chemoreceptors and ventilation causing PCO2 to oscillate around some fixed threshold value: PCO2 above this ventilatory threshold would stimulate excessive hyperventilation, driving PCO2 below the threshold and causing a subsequent apnoea. This hypothesis was tested by implanting micro-optodes into the hemocoel of Madagascar hissing cockroaches and measuring hemolymph PO2 and PCO2 simultaneously during continuous and discontinuous gas exchange. The mean hemolymph PCO2 of 1.9 kPa measured during continuous gas exchange was assumed to represent the threshold level stimulating ventilation, and this was compared with PCO2 levels recorded during DGCs elicited by decapitation. Cockroaches were also exposed to hypoxic (PO2 10 kPa) and hypercapnic (PCO2 2 kPa) gas mixtures to manipulate hemolymph PO2 and PCO2. Decapitated cockroaches maintained DGCs even when their hemolymph PCO2 was forced above or below the putative ∼2 kPa ventilation threshold, demonstrating that the characteristic oscillation between apnoea and gas exchange is not driven by a lag between changing hemolymph PCO2 and a PCO2 chemoreceptor with a fixed ventilatory threshold. However, it was observed that the gas exchange periods within the DGC were altered to enhance O2 uptake and CO2 release during hypoxia and hypercapnia exposure. This indicates that while respiratory chemoreceptors do modulate ventilatory activity in response to hemolymph gas levels, their role in initiating or terminating the gas exchange periods within the DGC remains unclear.
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Affiliation(s)
- Tormod T C Rowe
- Department of Zoology, University of British Columbia, Vancouver, B.C., V6T 1Z4, Canada
| | | | - Philip G D Matthews
- Department of Zoology, University of British Columbia, Vancouver, B.C., V6T 1Z4, Canada
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Lubawy J, Chowański S, Adamski Z, Słocińska M. Mitochondria as a target and central hub of energy division during cold stress in insects. Front Zool 2022; 19:1. [PMID: 34991650 PMCID: PMC8740437 DOI: 10.1186/s12983-021-00448-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 12/13/2021] [Indexed: 01/08/2023] Open
Abstract
Temperature stress is one of the crucial factors determining geographical distribution of insect species. Most of them are active in moderate temperatures, however some are capable of surviving in extremely high as well as low temperatures, including freezing. The tolerance of cold stress is a result of various adaptation strategies, among others the mitochondria are an important player. They supply cells with the most prominent energy carrier—ATP, needed for their life processes, but also take part in many other processes like growth, aging, protection against stress injuries or cell death. Under cold stress, the mitochondria activity changes in various manner, partially to minimize the damages caused by the cold stress, partially because of the decline in mitochondrial homeostasis by chill injuries. In the response to low temperature, modifications in mitochondrial gene expression, mtDNA amount or phosphorylation efficiency can be observed. So far study also showed an increase or decrease in mitochondria number, their shape and mitochondrial membrane permeability. Some of the changes are a trigger for apoptosis induced via mitochondrial pathway, that protects the whole organism against chill injuries occurring on the cellular level. In many cases, the observed modifications are not unequivocal and depend strongly on many factors including cold acclimation, duration and severity of cold stress or environmental conditions. In the presented article, we summarize the current knowledge about insect response to cold stress focusing on the role of mitochondria in that process considering differences in results obtained in different experimental conditions, as well as depending on insect species. These differentiated observations clearly indicate that it is still much to explore. ![]()
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Affiliation(s)
- Jan Lubawy
- Department of Animal Physiology and Developmental Biology, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland.
| | - Szymon Chowański
- Department of Animal Physiology and Developmental Biology, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland
| | - Zbigniew Adamski
- Department of Animal Physiology and Developmental Biology, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland.,Laboratory of Electron and Confocal Microscopy, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland
| | - Małgorzata Słocińska
- Department of Animal Physiology and Developmental Biology, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland
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Kanabar M, Bauer S, Ezedum ZM, Dwyer IP, Moore WS, Rodriguez G, Mall A, Littleton AT, Yudell M, Kanabar J, Tucker WJ, Daniels ER, Iqbal M, Khan H, Mirza A, Yu JC, O'Neal M, Volkenborn N, Pochron ST. Roundup negatively impacts the behavior and nerve function of the Madagascar hissing cockroach (Gromphadorhina portentosa). ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:10.1007/s11356-021-13021-6. [PMID: 33635453 DOI: 10.1007/s11356-021-13021-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Accepted: 02/15/2021] [Indexed: 06/12/2023]
Abstract
Glyphosate is the active ingredient in Roundup formulations. Glyphosate-based herbicides are used globally in agriculture, forestry, horticulture, and in urban settings. Glyphosate can persist for years in our soil, potentially impacting the soil-dwelling arthropods that are primary drivers of a suite of ecosystem services. Furthermore, although glyphosate is not generally classified as neurotoxic to insects, evidence suggests that it may cause nerve damage in other organisms. In a series of experiments, we used food to deliver environmentally realistic amounts of Roundup ready-to-use III, a common 2% glyphosate-based herbicide formulation that lists isopropylamine salt as its active ingredient, to Madagascar hissing cockroaches. We then assessed the impact of contamination on body mass, nerve health, and behavior. Contaminated food contained both 30.6 mg glyphosate and so-called inert ingredients. Food was refreshed weekly for 26-60 days, depending on the experiment. We found that consumption of contaminated food did not impact adult and juvenile survivorship or body weight. However, consumption of contaminated food decreased ventral nerve cord action-potential velocity by 32%, caused a 29% increase in respiration rate, and caused a 74.4% decrease in time spent on a motorized exercise wheel. Such changes in behavior may make cockroaches less capable of fulfilling their ecological service, such as pollinating or decomposing litter. Furthermore, their lack of coordination may make them more susceptible to predation, putting their population at risk. Given the decline of terrestrial insect abundance, understanding common risks to terrestrial insect populations has never been more critical. Results from our experiments add to the growing body of literature suggesting that this popular herbicide can act as a neurotoxin.
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Affiliation(s)
- Megha Kanabar
- Sustainability Studies Program, School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, 11794-3435, USA
| | - Samuel Bauer
- Sustainability Studies Program, School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, 11794-3435, USA
| | - Zimuzo M Ezedum
- Sustainability Studies Program, School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, 11794-3435, USA
| | - Ian P Dwyer
- Sustainability Studies Program, School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, 11794-3435, USA
| | - William S Moore
- Sustainability Studies Program, School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, 11794-3435, USA
| | - Gabriella Rodriguez
- Sustainability Studies Program, School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, 11794-3435, USA
| | - Aditya Mall
- Sustainability Studies Program, School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, 11794-3435, USA
| | - Anne T Littleton
- Sustainability Studies Program, School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, 11794-3435, USA
| | - Michael Yudell
- Sustainability Studies Program, School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, 11794-3435, USA
| | | | - Wade J Tucker
- Miller Place High School, Miller Place, NY, 11764, USA
| | - Emily R Daniels
- Sustainability Studies Program, School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, 11794-3435, USA
| | - Mohima Iqbal
- Sustainability Studies Program, School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, 11794-3435, USA
| | - Hira Khan
- Sustainability Studies Program, School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, 11794-3435, USA
| | - Ashra Mirza
- Sustainability Studies Program, School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, 11794-3435, USA
| | - Joshua C Yu
- Sustainability Studies Program, School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, 11794-3435, USA
| | - Marvin O'Neal
- Department of Biology, Stony Brook University, Stony Brook, NY, 11794-3435, USA
| | - Nils Volkenborn
- Marine Sciences Program, School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, 11794-3435, USA
| | - Sharon T Pochron
- Sustainability Studies Program, School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, 11794-3435, USA.
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Lubawy J, Słocińska M. Characterization of Gromphadorhina coquereliana hemolymph under cold stress. Sci Rep 2020; 10:12076. [PMID: 32694601 PMCID: PMC7374602 DOI: 10.1038/s41598-020-68941-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 06/25/2020] [Indexed: 02/06/2023] Open
Abstract
Low temperatures in nature occur together with desiccation conditions, causing changes in metabolic pathways and cellular dehydration, affecting hemolymph volume, water content and ion homeostasis. Although some research has been conducted on the effect of low temperature on Gromphadorhina coquereliana, showing that it can survive exposures to cold or even freezing, no one has studied the effect of cold on the hemolymph volume and the immune response of this cockroach. Here, we investigated the effect of low temperature (4 °C) on the abovementioned parameters, hemocyte morphology and total number. Cold stress affected hemocytes and the immune response, but not hemolymph volume. After stress, the number of circulating hemocytes decreased by 44.7%, but the ratio of apoptotic cells did not differ significantly between stressed and control individuals: 8.06% and 7.18%, respectively. The number of phagocyting hemocytes decreased by 16.66%, the hemocyte morphology drastically changed, and the F-actin cytoskeleton differed substantially in cold-stressed insects compared to control insects. Moreover, the surface area of the cells increased from 393.69 µm2 in the control to 458.38 µm2 in cold-treated animals. Together, our results show the links between cold stress and the cellular immune response, which probably results in the survival capability of this species.
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Affiliation(s)
- Jan Lubawy
- Department of Animal Physiology and Developmental Biology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland.
| | - Małgorzata Słocińska
- Department of Animal Physiology and Developmental Biology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
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Lubawy J, Daburon V, Chowański S, Słocińska M, Colinet H. Thermal stress causes DNA damage and mortality in a tropical insect. J Exp Biol 2019; 222:jeb.213744. [DOI: 10.1242/jeb.213744] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 10/28/2019] [Indexed: 01/12/2023]
Abstract
Cold tolerance is considered an important factor determining geographic distribution of insects. We've previously shown that despite tropical origin, cockroach Gromphadorinha coquereliana is capable of surviving exposures to cold. However, freezing tolerance of this species had not yet been examined. Low temperature is known to alter membranes integrity in insects but whether chilling or freezing compromises DNA integrity remains a matter of speculation. In the present study, we subjected the G. coquereliana adults to freezing to determine their supercooling point (SCP) and evaluated whether the cockroaches were capable of surviving partial and complete freezing. Next, we conducted single cell gel electrophoresis assay (SCGE) to determine whether heat, cold and freezing altered haemocytes DNA integrity. The SCP of this species was high and around -4.76°C, which is within typical range of freezing-tolerant species. Most cockroaches survived one day after partial ice formation (20% mortality), but died progressively in the next few days after cold stress (70% mortality after 4 days). One day after complete freezing, most insects died (70% mortality), and after 4 days, 90% of them had succumbed. The SCGE assays showed substantial level of DNA damage in haemocytes. When cockroaches were heat-stressed, the level of DNA damage was similar to that observed in the freezing treatment; though all heat-stressed insects survived. The study shows that G. coquereliana can surprisingly be considered as moderately freezing-tolerant species, and for first time that extreme low temperature stress can affect DNA integrity, suggesting that this cockroach may possess an efficient DNA repair system.
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Affiliation(s)
- Jan Lubawy
- Department of Animal Physiology and Development, Faculty of Biology, Adam Mickiewicz University in Poznań, Poland
| | | | - Szymon Chowański
- Department of Animal Physiology and Development, Faculty of Biology, Adam Mickiewicz University in Poznań, Poland
| | - Małgorzata Słocińska
- Department of Animal Physiology and Development, Faculty of Biology, Adam Mickiewicz University in Poznań, Poland
| | - Hervé Colinet
- ECOBIO – UMR 6553, Université de Rennes 1, CNRS, Rennes, France
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