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Andersen MK, Donini A, MacMillan HA. Measuring insect osmoregulation in vitro: A reference guide. Comp Biochem Physiol A Mol Integr Physiol 2024; 299:111751. [PMID: 39341353 DOI: 10.1016/j.cbpa.2024.111751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2024] [Revised: 09/24/2024] [Accepted: 09/25/2024] [Indexed: 10/01/2024]
Abstract
Osmoregulation is influenced by a wide variety of biotic and abiotic variables, and maintenance of systemic osmoregulatory homeostasis is critical to insect fitness. Because insects are so small, accurately quantifying renal organ function is technically challenging, and often requires specialized equipment. On top of this, nearly a century of toiling in the laboratory has led to a wide and still growing variety of methods that can be difficult for novice researchers to disentangle. Here, we provide a reference guide for the most used in vitro approaches in the study of insect osmoregulation, including the Ramsay assay, Ussing chamber, epithelial potential measurement, scanning ion-selective electrode technique, and hindgut assays. Along the way, we highlight the history of each methodological innovation.
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Affiliation(s)
| | - Andrew Donini
- Department of Biology, York University, Toronto M3J 1P3, Canada
| | - Heath A MacMillan
- Department of Biology and Institute of Biochemistry, Carleton University, Ottawa K1S 5B6, Canada.
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Durant AC, Donini A. Ammonia transport in the excretory system of mosquito larvae (Aedes aegypti): Rh protein expression and the transcriptome of the rectum. Comp Biochem Physiol A Mol Integr Physiol 2024; 294:111649. [PMID: 38670480 DOI: 10.1016/j.cbpa.2024.111649] [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: 12/23/2023] [Revised: 04/23/2024] [Accepted: 04/23/2024] [Indexed: 04/28/2024]
Abstract
The role of the mosquito excretory organs (Malpighian tubules, MT and hindgut, HG) in ammonia transport as well as expression and function of the Rhesus (Rh protein) ammonia transporters within these organs was examined in Aedes aegypti larvae and adult females. Immunohistological examination revealed that the Rh proteins are co-localized with V-type H+-ATPase (VA) to the apical membranes of MT and HG epithelia of both larvae and adult females. Of the two Rh transporter genes present in A. aegypti, AeRh50-1 and AeRh50-2, we show using quantitative real-time PCR (qPCR) and an RNA in-situ hybridization (ISH) assay that AeRh50-1 is the predominant Rh protein expressed in the excretory organs of larvae and adult females. Further assessment of AeRh50-1 function in larvae and adults using RNAi (i.e. dsRNA-mediated knockdown) revealed significantly decreased [NH4+] (mmol l-1) levels in the secreted fluid of larval MT which does not affect overall NH4+ transport rates, as well as significantly decreased NH4+ flux rates across the HG (haemolymph to lumen) of adult females. We also used RNA sequencing to identify the expression of ion transporters and enzymes within the rectum of larvae, of which limited information currently exists for this important osmoregulatory organ. Of the ammonia transporters in A. aegypti, AeRh50-1 transcript is most abundant in the rectum thus validating our immunohistochemical and RNA ISH findings. In addition to enriched VA transcript (subunits A and d1) in the rectum, we also identified high Na+-K+-ATPase transcript (α subunit) expression which becomes significantly elevated in response to HEA, and we also found enriched carbonic anhydrase 9, inwardly rectifying K+ channel Kir2a, and Na+-coupled cation-chloride (Cl-) co-transporter CCC2 transcripts. Finally, the modulation in excretory organ function and/or Rh protein expression was examined in relation to high ammonia challenge, specifically high environmental ammonia (HEA) rearing of larvae. NH4+ flux measurements using the scanning-ion selective electrode (SIET) technique revealed no significant differences in NH4+ transport across organs comprising the alimentary canal of larvae reared in HEA vs freshwater. Further, significantly increased VA activity, but not NKA, was observed in the MT of HEA-reared larvae. Relatively high Rh protein immunostaining persists within the hindgut epithelium, as well as the ovary, of females at 24-48 h post blood meal corresponding with previously demonstrated peak levels of ammonia formation. These data provide new insight into the role of the excretory organs in ammonia transport physiology and the contribution of Rh proteins in mediating ammonia movement across the epithelia of the MT and HG, and the first comprehensive examination of ion transporter and channel expression in the mosquito rectum.
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Affiliation(s)
- Andrea C Durant
- Department of Biology, University of Washington, Box 351800, Seattle, WA 98195-1800, USA
| | - Andrew Donini
- Department of Biology, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada.
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Dates J, Kolosov D. Voltage-gated ion channels as novel regulators of epithelial ion transport in the osmoregulatory organs of insects. FRONTIERS IN INSECT SCIENCE 2024; 4:1385895. [PMID: 38835480 PMCID: PMC11148248 DOI: 10.3389/finsc.2024.1385895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 05/01/2024] [Indexed: 06/06/2024]
Abstract
Voltage-gated ion channels (VGICs) respond to changes in membrane potential (Vm) and typically exhibit fast kinetic properties. They play an important role in signal detection and propagation in excitable tissues. In contrast, the role of VGICs in non-excitable tissues like epithelia is less studied and less clear. Studies in epithelia of vertebrates and invertebrates demonstrate wide expression of VGICs in epithelia of animals. Recently, VGICs have emerged as regulators of ion transport in the Malpighian tubules (MTs) and other osmoregulatory organs of insects. This mini-review aims to concisely summarize which VGICs have been implicated in the regulation of ion transport in the osmoregulatory epithelia of insects to date, and highlight select groups for further study. We have also speculated on the roles VGICs may potentially play in regulating processes connected directly to ion transport in insects (e.g., acid-base balance, desiccation, thermal tolerance). This review is not meant to be exhaustive but should rather serve as a thought-provoking collection of select existing highlights on VGICs, and to emphasize how understudied this mechanism of ion transport regulation is in insect epithelia.
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Affiliation(s)
- Jocelyne Dates
- Department of Biological Sciences, California State University San Marcos, San Marcos, CA, United States
| | - Dennis Kolosov
- Department of Biological Sciences, California State University San Marcos, San Marcos, CA, United States
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Farrell S, Dates J, Ramirez N, Hausknecht-Buss H, Kolosov D. Voltage-gated ion channels are expressed in the Malpighian tubules and anal papillae of the yellow fever mosquito (Aedes aegypti), and may regulate ion transport during salt and water imbalance. J Exp Biol 2024; 227:jeb246486. [PMID: 38197515 PMCID: PMC10912814 DOI: 10.1242/jeb.246486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 12/22/2023] [Indexed: 01/11/2024]
Abstract
Vectors of infectious disease include several species of Aedes mosquitoes. The life cycle of Aedes aegypti, the yellow fever mosquito, consists of a terrestrial adult and an aquatic larval life stage. Developing in coastal waters can expose larvae to fluctuating salinity, causing salt and water imbalance, which is addressed by two prime osmoregulatory organs - the Malpighian tubules (MTs) and anal papillae (AP). Voltage-gated ion channels (VGICs) have recently been implicated in the regulation of ion transport in the osmoregulatory epithelia of insects. In the current study, we: (i) generated MT transcriptomes of freshwater-acclimated and brackish water-exposed larvae of Ae. aegypti, (ii) detected expression of several voltage-gated Ca2+, K+, Na+ and non-ion-selective ion channels in the MTs and AP using transcriptomics, PCR and gel electrophoresis, (iii) demonstrated that mRNA abundance of many altered significantly following brackish water exposure, and (iv) immunolocalized CaV1, NALCN, TRP/Painless and KCNH8 in the MTs and AP of larvae using custom-made antibodies. We found CaV1 to be expressed in the apical membrane of MTs of both larvae and adults, and its inhibition to alter membrane potentials of this osmoregulatory epithelium. Our data demonstrate that multiple VGICs are expressed in osmoregulatory epithelia of Ae. aegypti and may play an important role in the autonomous regulation of ion transport.
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Affiliation(s)
- Serena Farrell
- Department of Biological Sciences, California State University San Marcos, 333 S. Twin Oaks Valley Road, San Marcos, CA 92096, USA
| | - Jocelyne Dates
- Department of Biological Sciences, California State University San Marcos, 333 S. Twin Oaks Valley Road, San Marcos, CA 92096, USA
| | - Nancy Ramirez
- Department of Biological Sciences, California State University San Marcos, 333 S. Twin Oaks Valley Road, San Marcos, CA 92096, USA
| | - Hannah Hausknecht-Buss
- Department of Biological Sciences, California State University San Marcos, 333 S. Twin Oaks Valley Road, San Marcos, CA 92096, USA
| | - Dennis Kolosov
- Department of Biological Sciences, California State University San Marcos, 333 S. Twin Oaks Valley Road, San Marcos, CA 92096, USA
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Lee CE, Charmantier G, Lorin-Nebel C. Mechanisms of Na + uptake from freshwater habitats in animals. Front Physiol 2022; 13:1006113. [PMID: 36388090 PMCID: PMC9644288 DOI: 10.3389/fphys.2022.1006113] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 09/28/2022] [Indexed: 07/20/2023] Open
Abstract
Life in fresh water is osmotically and energetically challenging for living organisms, requiring increases in ion uptake from dilute environments. However, mechanisms of ion uptake from freshwater environments are still poorly understood and controversial, especially in arthropods, for which several hypothetical models have been proposed based on incomplete data. One compelling model involves the proton pump V-type H+ ATPase (VHA), which energizes the apical membrane, enabling the uptake of Na+ (and other cations) via an unknown Na+ transporter (referred to as the "Wieczorek Exchanger" in insects). What evidence exists for this model of ion uptake and what is this mystery exchanger or channel that cooperates with VHA? We present results from studies that explore this question in crustaceans, insects, and teleost fish. We argue that the Na+/H+ antiporter (NHA) is a likely candidate for the Wieczorek Exchanger in many crustaceans and insects; although, there is no evidence that this is the case for fish. NHA was discovered relatively recently in animals and its functions have not been well characterized. Teleost fish exhibit redundancy of Na+ uptake pathways at the gill level, performed by different ion transporter paralogs in diverse cell types, apparently enabling tolerance of low environmental salinity and various pH levels. We argue that much more research is needed on overall mechanisms of ion uptake from freshwater habitats, especially on NHA and other potential Wieczorek Exchangers. Such insights gained would contribute greatly to our general understanding of ionic regulation in diverse species across habitats.
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Affiliation(s)
- Carol Eunmi Lee
- Department of Integrative Biology, University of Wisconsin, Madison, WI, United States
- MARBEC, Univ Montpellier, CNRS, Ifremer, IRD, Montpellier, France
| | - Guy Charmantier
- MARBEC, Univ Montpellier, CNRS, Ifremer, IRD, Montpellier, France
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Silver S, Donini A. Physiological responses of freshwater insects to salinity: molecular-, cellular- and organ-level studies. J Exp Biol 2021; 224:272480. [PMID: 34652452 DOI: 10.1242/jeb.222190] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Salinization of freshwater is occurring throughout the world, affecting freshwater biota that inhabit rivers, streams, ponds, marshes and lakes. There are many freshwater insects, and these animals are important for ecosystem health. These insects have evolved physiological mechanisms to maintain their internal salt and water balance based on a freshwater environment that has comparatively little salt. In these habitats, insects must counter the loss of salts and dilution of their internal body fluids by sequestering salts and excreting water. Most of these insects can tolerate salinization of their habitats to a certain level; however, when exposed to salinization they often exhibit markers of stress and impaired development. An understanding of the physiological mechanisms for controlling salt and water balance in freshwater insects, and how these are affected by salinization, is needed to predict the consequences of salinization for freshwater ecosystems. Recent research in this area has addressed the whole-organism response, but the purpose of this Review is to summarize the effects of salinization on the osmoregulatory physiology of freshwater insects at the molecular to organ level. Research of this type is limited, and pursuing such lines of inquiry will improve our understanding of the effects of salinization on freshwater insects and the ecosystems they inhabit.
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Affiliation(s)
- Sydney Silver
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada
| | - Andrew Donini
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada
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Morris C, O'Donnell MJ. Vacuolar H+-ATPase and Na+/K+-ATPase energize Na+ uptake mechanisms in the nuchal organ of the hyperregulating freshwater crustacean Daphnia magna. J Exp Biol 2021; 224:269112. [PMID: 34115859 DOI: 10.1242/jeb.242205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 05/06/2021] [Indexed: 11/20/2022]
Abstract
The nuchal organ of the embryos and neonates of the cladoceran, Daphnia magna, has been shown to be a site of Na+ influx and H+, NH4+ and Cl- efflux. This study combines the scanning ion-selective electrode technique with application of inhibitors of specific transporters to assess the mechanisms of Na+ transport across the nuchal organ. Na+ influx across the nuchal organ was inhibited both by inhibitors of the Na+/K+-ATPase (ouabain, bufalin) and by inhibitors of the vacuolar H+-ATPase (bafilomycin, N-ethylmaleimde, 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole, KM91104, S-nitrosoglutathione). Na+ influx was unaffected by the epithelial Na+ channel blocker benzamil, but was sensitive to ethylisopropyl amiloride and elevated external ammonium concentrations, consistent with roles for Na+/H+ and Na+/NH4+ exchangers in the apical membrane but not Na+ channels. Transport across the basolateral membrane into the haemolymph is proposed to involve the Na+/K+-ATPase and a thiazide-sensitive Na+/Cl- cotransporter.
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Affiliation(s)
- Carolyn Morris
- Department of Biology, McMaster University, Hamilton, ON, Canada, L8S 4K1
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Nesbitt JE, Swei A, Hunt C, Dotson EM, Toner M, Sandlin RD. Cryoprotectant toxicity and hypothermic sensitivity among Anopheles larvae. Cryobiology 2020; 99:106-113. [PMID: 33382993 DOI: 10.1016/j.cryobiol.2020.12.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 11/30/2020] [Accepted: 12/23/2020] [Indexed: 01/06/2023]
Abstract
Laboratory rearing of mosquitoes is commonly practiced by researchers studying mosquito-borne infectious diseases and vector control methods. In the absence of cryopreservation methods to stabilize unique or genetically modified strains, mosquito lines must be continuously maintained, a laborious process that risks selection effects, contamination, and genetic drift. Towards the development of a cryopreservation protocol, several commonly used cryoprotectants were systematically characterized here both individually and as cocktails. Among first instar, feeding-stage An. gambiae and An. stephensi larvae, cryoprotectant toxicity followed the order of dimethyl sulfoxide > ethylene glycol > methanol. The resulting LD50 values were used as the basis for the development of cryoprotectant cocktail solutions, where formulation optimization was streamlined using Taguchi methods of experimental design. Sensitivity to hypothermia was further evaluated to determine the feasibility of cryoprotectant loading at reduced temperatures and slow cooling approaches to cryopreservation. The information described here contributes to the knowledge base necessary to inform the development of a cryopreservation protocol for Anopheles larvae.
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Affiliation(s)
- Jenny E Nesbitt
- BioMEMS Resource Center, Center for Engineering in Medicine, & Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
| | - Anisa Swei
- BioMEMS Resource Center, Center for Engineering in Medicine, & Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
| | - Catherine Hunt
- Centers for Disease Control and Prevention, Atlanta, GA, USA.
| | - Ellen M Dotson
- Centers for Disease Control and Prevention, Atlanta, GA, USA.
| | - Mehmet Toner
- BioMEMS Resource Center, Center for Engineering in Medicine, & Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
| | - Rebecca D Sandlin
- BioMEMS Resource Center, Center for Engineering in Medicine, & Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
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Misyura L, Grieco Guardian E, Durant AC, Donini A. A comparison of aquaporin expression in mosquito larvae (Aedes aegypti) that develop in hypo-osmotic freshwater and iso-osmotic brackish water. PLoS One 2020; 15:e0234892. [PMID: 32817668 PMCID: PMC7440623 DOI: 10.1371/journal.pone.0234892] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 06/30/2020] [Indexed: 12/23/2022] Open
Abstract
The mosquito Aedes aegypti vectors the arboviral diseases yellow fever, dengue, Zika and chikungunya. Larvae are usually found developing in freshwater; however, more recently they have been increasingly found in brackish water, potential habitats which are traditionally ignored by mosquito control programs. Aedes aegypti larvae are osmo-regulators maintaining their hemolymph osmolarity in a range of ~ 250 to 300 mOsmol l-1. In freshwater, the larvae must excrete excess water while conserving ions while in brackish water, they must alleviate an accumulation of salts. The compensatory physiological mechanisms must involve the transport of ions and water but little is known about the water transport mechanisms in the osmoregulatory organs of these larvae. Water traverses cellular membranes predominantly through transmembrane proteins named aquaporins (AQPs) and Aedes aegypti possesses 6 AQP homologues (AaAQP1 to 6). The objective of this study was to determine if larvae that develop in freshwater or brackish water have differential aquaporin expression in osmoregulatory organs, which could inform us about the relative importance and function of aquaporins to mosquito survival under these different osmotic conditions. We found that AaAQP transcript abundance was similar in organs of freshwater and brackish water mosquito larvae. Furthermore, in the Malpighian tubules and hindgut AaAQP protein abundance was unaffected by the rearing conditions, but in the gastric caeca the protein level of one aquaporin, AaAQP1 was elevated in brackish water. We found that AaAQP1 was expressed apically while AaAQP4 and AaAQP5 were found to be apical and/or basal in the epithelia of osmoregulatory organs. Overall, the results suggest that aquaporin expression in the osmoregulatory organs is mostly consistent between larvae that are developing in freshwater and brackish water. This suggests that aquaporins may not have major roles in adapting to longterm survival in brackish water or that aquaporin function may be regulated by other mechanisms like post-translational modifications.
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Affiliation(s)
- Lidiya Misyura
- Department of Biology, York University, Toronto, Ontario, Canada
| | | | | | - Andrew Donini
- Department of Biology, York University, Toronto, Ontario, Canada
- * E-mail:
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Morris C, O'Donnell M. Multiple functions of ion transport by the nuchal organ in embryos and neonates of the freshwater branchiopod crustacean Daphnia magna. ACTA ACUST UNITED AC 2019; 222:jeb.211128. [PMID: 31645374 DOI: 10.1242/jeb.211128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 10/18/2019] [Indexed: 01/07/2023]
Abstract
The nuchal organ, also referred to as the dorsal organ or neck organ, is a dorsal structure located posteriorly to the compound eye, between the bases of the second antennae of embryonic and neonate branchiopod crustaceans such as the water flea, Daphnia magna The ultrastructure of the nuchal organ is similar to ion-transporting tissues in other crustaceans, including abundant mitochondria and extensive amplification of apical and basal plasma membranes through microvilli and infoldings, but direct evidence for ion transport is lacking. We used the scanning ion-selective electrode technique to measure transport of Na+, K+, H+, Cl-, NH4 + and Ca2+ across the nuchal organ and body surface of embryos and neonates bathed in dechlorinated Hamilton tap water. Influx of Na+ and efflux of H+ and NH4 + was found to occur across the nuchal organ of both embryos and neonates. We propose that the efflux of K+ and Cl- across the nuchal organ in embryos is related to the expansion of the haemocoel and release of intracellular solutes into the extracellular space during development. K+ is taken up across the nuchal organ later during development, coincident with expansion of the intracellular compartment through the development of gills and other organs. Ca2+ influx across the nuchal organ and body surface of neonates but not embryos is presumably related to calcification of the exoskeleton. Increases in the levels of Na+ and Ca2+ in the water within the brood chamber suggest maternal provisioning of ions for uptake by the embryos. Our data thus support roles for the nuchal organ in ionoregulation, pH regulation and nitrogenous waste excretion.
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Affiliation(s)
- Carolyn Morris
- Department of Biology, McMaster University, Hamilton, ON, Canada L8S 4K1
| | - Michael O'Donnell
- Department of Biology, McMaster University, Hamilton, ON, Canada L8S 4K1
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Wang Z, Perumalsamy H, Wang X, Ahn YJ. Toxicity and possible mechanisms of action of honokiol from Magnolia denudata seeds against four mosquito species. Sci Rep 2019; 9:411. [PMID: 30674912 PMCID: PMC6344527 DOI: 10.1038/s41598-018-36558-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 11/22/2018] [Indexed: 12/18/2022] Open
Abstract
This study was performed to determine the toxicity and possible mechanism of the larvicidal action of honokiol, extracted from Magnolia denudata seeds, and its 10 related compounds against third-instar larvae of insecticide-susceptible Culex pipiens pallens, Aedes aegypti, and Aedes albopictus and Anopheles sinensis resistant to deltamethrin and temephos. Honokiol (LC50, 6.13–7.37 mg/L) was highly effective against larvae of all of the four mosquito species, although the toxicity of the compound was lower than that of the synthetic larvicide temephos. Structure–activity relationship analyses indicated that electron donor and/or bulky groups at the ortho or para positions of the phenol were required for toxicity. Honokiol moderately inhibited acetylcholinesterase and caused a considerable increase in cyclic AMP levels, indicating that it might act on both acetylcholinesterase and octopaminergic receptors. Microscopy analysis clearly indicated that honokiol was mainly targeted to the midgut epithelium and anal gills, resulting in variably dramatic degenerative responses of the midgut through sequential epithelial disorganization. Honokiol did not affect the AeCS1 mRNA expression level in Ae. aegypti larvae, but did enhance expression of the genes encoding vacuolar-type H+-ATPase and aquaporin 4, indicating that it may disturb the Na+, Cl− and K+ co-transport systems. These results demonstrate that honokiol merits further study as a potential larvicide, with a specific target site, and as a lead molecule for the control of mosquito populations.
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Affiliation(s)
- Zhangqian Wang
- Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, Republic of Korea.,Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University), Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, Hubei, China
| | - Haribalan Perumalsamy
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Xue Wang
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Young-Joon Ahn
- Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, Republic of Korea. .,Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea.
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12
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Quantification of Mg2+, Ca2+ and H+ transport by the gastrointestinal tract of the goldfish, Carassius auratus, using the Scanning Ion-selective Electrode Technique (SIET). PLoS One 2018; 13:e0207782. [PMID: 30513099 PMCID: PMC6279021 DOI: 10.1371/journal.pone.0207782] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 11/06/2018] [Indexed: 11/28/2022] Open
Abstract
An in vitro gut-sac technique and the scanning ion-selective electrode technique (SIET) were used to characterize Mg2+, Ca2+, and H+ transport at both the mucosal and serosal surfaces of non-everted and everted gastrointestinal tissues obtained from Carassius auratus. As part of the study, two magnesium ionophores were compared (II vs. VI). Unfed animals displayed uniform transport of all ions along the intestine. Feeding resulted in elevated Mg2+ and Ca2+ transport when the gut lumen contained chyme however, under symmetrical conditions this increased transport rate was absent. Furthermore, zonation of divalent cation transport was present for both Ca2+ and Mg2+ under non-symmetrical conditions while the zonation remained for Ca2+ alone under symmetrical conditions. High dietary Mg2+ decreased absorption and induced secretion of Mg2+ in the posterior intestine. Uptake kinetics in the esophagus suggest large diffusive and/or convective components based on a linear relationship between Mg2+ transport and concentration and lack of inhibition by ouabain, an inhibitor of Na+-K+-ATPase. In contrast, kinetics in the rectum were suggestive of a low affinity, saturable carrier-mediated pathway. A decrease in Mg2+ and Ca2+ transport was observed in the posterior intestine (both at the mucosal and serosal surfaces) in response to ouabain. This impact was greatest for Ca2+ transport and when applied to the mucosal fluid and measured in everted preparations. In contrast a putative Mg2+ transport inhibitor, cobalt(III)hexamine-chloride, did not affect Mg2+ transport. This is the first study to use SIET approaches to study ion transport in the gut of teleost fish. This is also the first study to provide characterization of Mg2+ transport in the gut of C. auratus. Due to the limited selectivity of Magnesium ionophore II, subsequent studies of tissues bathed in physiological saline should be made using Magnesium Ionophore VI.
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Durant AC, Donini A. Evidence that Rh proteins in the anal papillae of the freshwater mosquito Aedes aegypti are involved in the regulation of acid-base balance in elevated salt and ammonia environments. ACTA ACUST UNITED AC 2018; 221:jeb.186866. [PMID: 30305376 DOI: 10.1242/jeb.186866] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 10/04/2018] [Indexed: 12/13/2022]
Abstract
Aedes aegypti commonly inhabit ammonia-rich sewage effluents in tropical regions of the world where the adults are responsible for the spread of disease. Studies have shown the importance of the anal papillae of A. aegypti in ion uptake and ammonia excretion. The anal papillae express ammonia transporters and Rhesus (Rh) proteins which are involved in ammonia excretion and studies have primarily focused on understanding these mechanisms in freshwater. In this study, effects of rearing larvae in salt (5 mmol l-1 NaCl) or ammonia (5 mmol l-1 NH4Cl) on physiological endpoints of ammonia and ion regulation were assessed. In anal papillae of NaCl-reared larvae, Rh protein expression increased, NHE3 transcript abundance decreased and NH4 + excretion increased, and this coincided with decreased hemolymph [NH4 +] and pH. We propose that under these conditions, larvae excrete more NH4 + through Rh proteins as a means of eliminating acid from the hemolymph. In anal papillae of NH4Cl-reared larvae, expression of an apical ammonia transporter and the Rh proteins decreased, the activities of NKA and VA decreased and increased, respectively, and this coincided with hemolymph acidification. The results present evidence for a role of Rh proteins in acid-base balance in response to elevated levels of salt, whereby ammonia is excreted as an acid equivalent.
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Affiliation(s)
- Andrea C Durant
- Department of Biology, York University, Toronto, ON, Canada M3J 1P3
| | - Andrew Donini
- Department of Biology, York University, Toronto, ON, Canada M3J 1P3
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Dow JA. The essential roles of metal ions in insect homeostasis and physiology. CURRENT OPINION IN INSECT SCIENCE 2017; 23:43-50. [PMID: 29129281 DOI: 10.1016/j.cois.2017.07.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 07/03/2017] [Accepted: 07/06/2017] [Indexed: 06/07/2023]
Abstract
Metal ions play distinct roles in living organisms, including insects. Some, like sodium and potassium, are central players in osmoregulation and 'blood and guts' transport physiology, and have been implicated in cold adaptation. Calcium is a key player as a second messenger, and as a structural element. Other metals, particularly those with multiple redox states, can be cofactors in many metalloenzymes, but can contribute to toxic oxidative stress on the organism in excess. This short review selects some examples where classical knowledge has been supplemented with recent advances, in order to emphasize the importance of metals as essential nutrients for insect survival.
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Affiliation(s)
- Julian At Dow
- Institute of Molecular, Cell & Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
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15
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Piermarini PM, Akuma DC, Crow JC, Jamil TL, Kerkhoff WG, Viel KCMF, Gillen CM. Differential expression of putative sodium-dependent cation-chloride cotransporters in Aedes aegypti. Comp Biochem Physiol A Mol Integr Physiol 2017; 214:40-49. [PMID: 28923771 DOI: 10.1016/j.cbpa.2017.09.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 09/08/2017] [Accepted: 09/08/2017] [Indexed: 11/18/2022]
Abstract
The yellow fever mosquito, Aedes aegypti, has three genes that code for proteins with sequence similarity to vertebrate Na+-K+-Cl- cotransporters (NKCCs) of the solute-linked carrier 12 superfamily of cation-chloride cotransporters (CCCs). We hypothesized that these mosquito NKCC orthologues have diverged to perform distinct roles in salt secretion and absorption. In phylogenetic analyses, one protein (aeNKCC1) groups with a Drosophila melanogaster NKCC that mediates salt secretion whereas two others (aeCCC2 and aeCCC3) group with a Drosophila transporter that is not functionally characterized. The aeCCC2 and aeCCC3 genes probably result from a tandem gene duplication in the mosquito lineage; they have similar exon structures and are consecutive in genomic DNA. Predicted aeCCC2 and aeCCC3 proteins differ from aeNKCC1 and vertebrate NKCCs in residues from the third transmembrane domain known to influence ion and inhibitor binding. Quantitative PCR revealed that aeNKCC1 and aeCCC2 were approximately equally expressed in larvae and adults, whereas aeCCC3 was approximately 100-fold more abundant in larvae than in adults. In larval tissues, aeCCC2 was approximately 2-fold more abundant in Malpighian tubules compared to anal papillae. In contrast, aeCCC3 was nearly 100-fold more abundant in larval anal papillae compared to Malpighian tubules, suggesting a role in absorption. Western blots with polyclonal antibodies against isoform-specific peptides revealed stronger aeCCC2 immunoreactivity in adults versus larvae, whereas aeCCC3 immunoreactivity was stronger in larvae versus adults. The differential expression pattern of aeCCC2 and aeCCC3, and their sequence divergence in transmembrane domains, suggests that they may have different roles in transepithelial salt transport.
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Affiliation(s)
- Peter M Piermarini
- Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH, United States
| | - Daniel C Akuma
- Department of Biology, Kenyon College, Gambier, OH, United States
| | - John C Crow
- Department of Biology, Kenyon College, Gambier, OH, United States
| | - Taylor L Jamil
- Department of Biology, Kenyon College, Gambier, OH, United States
| | - Willa G Kerkhoff
- Department of Biology, Kenyon College, Gambier, OH, United States
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16
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Abstract
In chemistry, the ratio of all dissolved solutes to the solution's volume yields the osmotic concentration. The present Review uses this chemical perspective to examine how insects deal with challenges to extracellular fluid (ECF) volume, solute content and osmotic concentration (pressure). Solute/volume plots of the ECF (hemolymph) reveal that insects tolerate large changes in all three of these ECF variables. Challenges beyond those tolerances may be 'corrected' or 'compensated'. While a correction simply reverses the challenge, compensation accommodates the challenge with changes in the other two variables. Most insects osmoregulate by keeping ECF volume and osmotic concentration within a wide range of tolerance. Other insects osmoconform, allowing the ECF osmotic concentration to match the ambient osmotic concentration. Aphids are unique in handling solute and volume loads largely outside the ECF, in the lumen of the gut. This strategy may be related to the apparent absence of Malpighian tubules in aphids. Other insects can suspend ECF homeostasis altogether in order to survive extreme temperatures. Thus, ECF homeostasis in insects is highly dynamic and plastic, which may partly explain why insects remain the most successful class of animals in terms of both species number and biomass.
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Affiliation(s)
- Klaus W Beyenbach
- Department of Biomedical Sciences, Cornell University, Ithaca, NY 14853, USA
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17
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Jonusaite S, Kelly SP, Donini A. Identification of the septate junction protein gliotactin in the mosquito Aedes aegypti: evidence for a role in increased paracellular permeability in larvae. ACTA ACUST UNITED AC 2017; 220:2354-2363. [PMID: 28432154 DOI: 10.1242/jeb.156125] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 04/11/2017] [Indexed: 12/15/2022]
Abstract
Septate junctions (SJs) regulate paracellular permeability across invertebrate epithelia. However, little is known about the function of SJ proteins in aquatic invertebrates. In this study, a role for the transmembrane SJ protein gliotactin (Gli) in the osmoregulatory strategies of larval mosquito (Aedes aegypti) was examined. Differences in gli transcript abundance were observed between the midgut, Malpighian tubules, hindgut and anal papillae of A. aegypti, which are epithelia that participate in larval mosquito osmoregulation. Western blotting of Gli revealed its presence in monomer, putative dimer and alternatively processed protein forms in different larval mosquito organs. Gli localized to the entire SJ domain between midgut epithelial cells and showed a discontinuous localization along the plasma membranes of epithelial cells of the rectum as well as the syncytial anal papillae epithelium. In the Malpighian tubules, Gli immunolocalization was confined to SJs between the stellate and principal cells. Rearing larvae in 30% seawater caused an increase in Gli protein abundance in the anterior midgut, Malpighian tubules and hindgut. Transcriptional knockdown of gli using dsRNA reduced Gli protein abundance in the midgut and increased the flux rate of the paracellular permeability marker, polyethylene glycol (molecular weight 400 Da; PEG-400). Data suggest that in larval A. aegypti, Gli participates in the maintenance of salt and water balance and that one role for Gli is to participate in the regulation of paracellular permeability across the midgut of A. aegypti in response to changes in environmental salinity.
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Affiliation(s)
- Sima Jonusaite
- Department of Biology, York University, Toronto, Ontario, Canada M3J 1P3
| | - Scott P Kelly
- Department of Biology, York University, Toronto, Ontario, Canada M3J 1P3
| | - Andrew Donini
- Department of Biology, York University, Toronto, Ontario, Canada M3J 1P3
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18
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Griffith MB. Toxicological perspective on the osmoregulation and ionoregulation physiology of major ions by freshwater animals: Teleost fish, crustacea, aquatic insects, and Mollusca. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2017; 36:576-600. [PMID: 27808448 PMCID: PMC6114146 DOI: 10.1002/etc.3676] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 04/11/2016] [Accepted: 11/01/2016] [Indexed: 05/21/2023]
Abstract
Anthropogenic sources increase freshwater salinity and produce differences in constituent ions compared with natural waters. Moreover, ions differ in physiological roles and concentrations in intracellular and extracellular fluids. Four freshwater taxa groups are compared, to investigate similarities and differences in ion transport processes and what ion transport mechanisms suggest about the toxicity of these or other ions in freshwater. Although differences exist, many ion transporters are functionally similar and may belong to evolutionarily conserved protein families. For example, the Na+ /H+ -exchanger in teleost fish differs from the H+ /2Na+ (or Ca2+ )-exchanger in crustaceans. In osmoregulation, Na+ and Cl- predominate. Stenohaline freshwater animals hyperregulate until they are no longer able to maintain hypertonic extracellular Na+ and Cl- concentrations with increasing salinity and become isotonic. Toxic effects of K+ are related to ionoregulation and volume regulation. The ionic balance between intracellular and extracellular fluids is maintained by Na+ /K+ -adenosine triphosphatase (ATPase), but details are lacking on apical K+ transporters. Elevated H+ affects the maintenance of internal Na+ by Na+ /H+ exchange; elevated HCO3- inhibits Cl- uptake. The uptake of Mg2+ occurs by the gills or intestine, but details are lacking on Mg2+ transporters. In unionid gills, SO42- is actively transported, but most epithelia are generally impermeant to SO42- . Transporters of Ca2+ maintain homeostasis of dissolved Ca2+ . More integration of physiology with toxicology is needed to fully understand freshwater ion effects. Environ Toxicol Chem 2017;36:576-600. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.
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Affiliation(s)
- Michael B. Griffith
- Office of Research and Development, National Center for Environmental Assessment, US Environmental Protection Agency, Cincinnati, Ohio, USA
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19
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Salinity alters snakeskin and mesh transcript abundance and permeability in midgut and Malpighian tubules of larval mosquito, Aedes aegypti. Comp Biochem Physiol A Mol Integr Physiol 2016; 205:58-67. [PMID: 27988380 DOI: 10.1016/j.cbpa.2016.12.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 12/09/2016] [Accepted: 12/12/2016] [Indexed: 11/21/2022]
Abstract
This study examined the distribution and localization of the septate junction (SJ) proteins snakeskin (Ssk) and mesh in osmoregulatory organs of larval mosquito (Aedes aegypti), as well as their response to altered environmental salt levels. Ssk and mesh transcripts and immunoreactivity were detected in tissues of endodermal origin such as the midgut and Malpighian tubules of A. aegypti larvae, but not in ectodermally derived hindgut and anal papillae. Immunolocalization of Ssk and mesh in the midgut and Malpighian tubules indicated that both proteins are concentrated at regions of cell-cell contact between epithelial cells. Transcript abundance of ssk and mesh was higher in the midgut and Malpighian tubules of brackish water (BW, 30% SW) reared A. aegypti larvae when compared with freshwater (FW) reared animals. Therefore, [3H]polyethylene glycol (MW 400Da, PEG-400) flux was examined across isolated midgut and Malpighian tubule preparations as a measure of their paracellular permeability. It was found that PEG-400 flux was greater across the midgut of BW versus FW larvae while the Malpighian tubules of BW-reared larvae had reduced PEG-400 permeability in conjunction with increased Cl- secretion compared to FW animals. Taken together, data suggest that Ssk and mesh are found in smooth SJs (sSJs) of larval A. aegypti and that their abundance alters in association with changes in epithelial permeability when larvae reside in water of differing salt content. This latter observation suggests that Ssk and mesh play a role in the homeostatic control of salt and water balance in larval A. aegypti.
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20
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The response of claudin-like transmembrane septate junction proteins to altered environmental ion levels in the larval mosquito Aedes aegypti. J Comp Physiol B 2016; 186:589-602. [DOI: 10.1007/s00360-016-0979-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Revised: 03/06/2016] [Accepted: 03/12/2016] [Indexed: 11/26/2022]
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21
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Chasiotis H, Ionescu A, Misyura L, Bui P, Fazio K, Wang J, Patrick M, Weihrauch D, Donini A. An animal homolog of plant Mep/Amt transporters promotes ammonia excretion by the anal papillae of the disease vector mosquito Aedes aegypti. ACTA ACUST UNITED AC 2016; 219:1346-55. [PMID: 26944496 DOI: 10.1242/jeb.134494] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 02/22/2016] [Indexed: 12/16/2022]
Abstract
The transcripts of three putative ammonia (NH3/NH4 (+)) transporters, Rhesus-like glycoproteins AeRh50-1, AeRh50-2 and Amt/Mep-like AeAmt1 were detected in the anal papillae of larval Aedes aegypti Quantitative PCR studies revealed 12-fold higher transcript levels of AeAmt1 in anal papillae relative to AeRh50-1, and levels of AeRh50-2 were even lower. Immunoblotting revealed AeAmt1 in anal papillae as a pre-protein with putative monomeric and trimeric forms. AeAmt1 was immunolocalized to the basal side of the anal papillae epithelium where it co-localized with Na(+)/K(+)-ATPase. Ammonium concentration gradients were measured adjacent to anal papillae using the scanning ion-selective electrode technique (SIET) and used to calculate ammonia efflux by the anal papillae. dsRNA-mediated reductions in AeAmt1 decreased ammonia efflux at larval anal papillae and significantly increased ammonia levels in hemolymph, indicating a principal role for AeAmt1 in ammonia excretion. Pharmacological characterization of ammonia transport mechanisms in the anal papillae suggests that, in addition to AeAmt1, the ionomotive pumps V-type H(+)-ATPase and Na(+)/K(+)-ATPase as well as NHE3 are involved in ammonia excretion at the anal papillae.
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Affiliation(s)
- Helen Chasiotis
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3
| | - Adrian Ionescu
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3
| | - Lidiya Misyura
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3
| | - Phuong Bui
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3
| | - Kimberly Fazio
- Department of Biology, University of San Diego, 5998 Alcala Park, San Diego, CA 92110, USA
| | - Jason Wang
- Department of Biology, University of San Diego, 5998 Alcala Park, San Diego, CA 92110, USA
| | - Marjorie Patrick
- Department of Biology, University of San Diego, 5998 Alcala Park, San Diego, CA 92110, USA
| | - Dirk Weihrauch
- Department of Biological Sciences, University of Manitoba, 50 Sifton Road, Winnipeg, Manitoba, Canada R3T 2N2
| | - Andrew Donini
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3
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22
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Occluding junctions of invertebrate epithelia. J Comp Physiol B 2015; 186:17-43. [DOI: 10.1007/s00360-015-0937-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 09/12/2015] [Accepted: 09/22/2015] [Indexed: 01/30/2023]
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23
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Weihrauch D, O’Donnell MJ. Links between Osmoregulation and Nitrogen-Excretion in Insects and Crustaceans. Integr Comp Biol 2015; 55:816-29. [DOI: 10.1093/icb/icv013] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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24
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Larsen EH, Deaton LE, Onken H, O'Donnell M, Grosell M, Dantzler WH, Weihrauch D. Osmoregulation and Excretion. Compr Physiol 2014; 4:405-573. [DOI: 10.1002/cphy.c130004] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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25
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Robertson L, Donini A, Lange AB. K+ absorption by locust gut and inhibition of ileal K+ and water transport by FGLamide allatostatins. J Exp Biol 2014; 217:3377-85. [DOI: 10.1242/jeb.101774] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Abstract
The Scanning Ion-Selective Electrode Technique (SIET) was utilized for the first time in Locusta migratoria to characterize K+ transport along the digestive tract and to determine the effect of two locust FGLamide allatostatins (FGLa/ASTs) on K+ transport: a previously sequenced FGLa/AST from Schistocerca gregaria (Scg-AST-6; ARPYSFGL-NH2) and a newly sequenced FGLa/AST from L. migratoria (Locmi-FGLa/AST-2; LPVYNFGL-NH2). Regional differences in K+ fluxes along the gut were evident, where K+ efflux in vitro (or absorption into the hemolymph in vivo) was greatest at the anterior ileum, and lowest at the colon. Ileal K+ efflux was inhibited by both Scg-AST-6 and Locmi-FGLa/AST-2, with maximal inhibition at 10-10 and 10-11 M, respectively. Both FGLa/ASTs also inhibited cAMP-stimulated K+ efflux from the ileum. Locmi-FGLa/AST-2 also inhibited efflux of water across the ileum. Locusts are terrestrial insects living in dry climates, risking desiccation and making water conservation a necessity. The results suggest that FGLa/ASTs may be acting as diuretics by increasing K+ excretion and therefore increasing water excretion. Thus, it is likely that FGLa/ASTs are involved in the control of hemolymph water and ion levels during feeding and digestion, to help the locust deal with the excess K+ load (and subsequently fluid) when the meal is processed.
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26
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Perumalsamy H, Kim JR, Oh SM, Jung JW, Ahn YJ, Kwon HW. Novel histopathological and molecular effects of natural compound pellitorine on larval midgut epithelium and anal gills of Aedes aegypti. PLoS One 2013; 8:e80226. [PMID: 24260359 PMCID: PMC3832413 DOI: 10.1371/journal.pone.0080226] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 10/01/2013] [Indexed: 11/19/2022] Open
Abstract
The yellow fever mosquito, Aedes aegypti, is a vector for transmitting dengue fever and yellow fever. In this study, we assessed the histopathological and molecular effects of pellitorine, an isobutylamide alkaloid, on the third instar of Ae. aegypti larvae. At 5 mg/l concentration of pellitorine, the whole body of the treated larvae became dark in color, particularly damaged thorax and abdominal regions. Pellitorine was targeted mainly on midgut epithelium and anal gills, indicating variably dramatic degenerative responses of the midgut through a sequential epithelial disorganization. The anterior and posterior midgut was entirely necrosed, bearing only gut lumen residues inside the peritrophic membranes. Pellitorine caused comprehensive damage of anal gill cells and branches of tracheole and debris was found in hemolymph of the anal gills. RT-PCR analysis indicates that the compound inhibited gene expression encoding V-type H+-ATPase and aquaporine 4 after treatment with 2.21 mg/l pellitorine. These results verify that pellitorine merits further study as a potential larvicide with a specific target site and a lead molecule for the control of mosquito populations.
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Affiliation(s)
- Haribalan Perumalsamy
- Research Institute for Agriculture and Life Science, Seoul National University, Seoul, Republic of Korea
- WCU Biomodulation Major, Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
| | - Jun-Ran Kim
- Research Institute for Agriculture and Life Science, Seoul National University, Seoul, Republic of Korea
- WCU Biomodulation Major, Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
| | - Sang Mi Oh
- WCU Biomodulation Major, Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
| | - Je Won Jung
- WCU Biomodulation Major, Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
| | - Young-Joon Ahn
- WCU Biomodulation Major, Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
- * E-mail: (Y-JA); (HWK)
| | - Hyung Wook Kwon
- WCU Biomodulation Major, Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
- * E-mail: (Y-JA); (HWK)
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27
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Jonusaite S, Kelly SP, Donini A. Tissue-specific ionomotive enzyme activity and K+ reabsorption reveal the rectum as an important ionoregulatory organ in larval Chironomus riparius exposed to varying salinity. ACTA ACUST UNITED AC 2013; 216:3637-48. [PMID: 23788699 DOI: 10.1242/jeb.089219] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A role for the rectum in the ionoregulatory homeostasis of larval Chironomus riparius was revealed by rearing animals in different saline environments and examining: (1) the spatial distribution and activity of keystone ionomotive enzymes Na(+)-K(+)-ATPase (NKA) and V-type H(+)-ATPase (VA) in the alimentary canal, and (2) rectal K(+) transport with the scanning ion-selective electrode technique (SIET). NKA and VA activity were measured in four distinct regions of the alimentary canal as follows: the combined foregut and anterior midgut, the posterior midgut, the Malpighian tubules and the hindgut. Both enzymes exhibited 10-20 times greater activity in the hindgut relative to all other areas. When larvae were reared in either ion-poor water (IPW) or freshwater (FW), no significant difference in hindgut enzyme activity was observed. However, in larvae reared in brackish water (BW), NKA and VA activity in the hindgut significantly decreased. Immunolocalization of NKA and VA in the hindgut revealed that the bulk of protein was located in the rectum. Therefore, K(+) transport across the rectum was examined using SIET. Measurement of K(+) flux along the rectum revealed a net K(+) reabsorption that was reduced fourfold in BW-reared larvae versus larvae reared in FW or IPW. Inhibition of NKA with ouabain, VA with bafilomycin and K(+) channels with charybdotoxin diminished rectal K(+) reabsorption in FW- and IPW-reared larvae, but not BW-reared larvae. Data suggest that the rectum of C. riparius plays an important role in allowing these larvae to cope with dilute as well as salinated environmental conditions.
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Affiliation(s)
- Sima Jonusaite
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada
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28
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Weihrauch D, Donini A, O'Donnell MJ. Ammonia transport by terrestrial and aquatic insects. JOURNAL OF INSECT PHYSIOLOGY 2012; 58:473-87. [PMID: 22100291 DOI: 10.1016/j.jinsphys.2011.11.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 11/03/2011] [Accepted: 11/04/2011] [Indexed: 05/13/2023]
Abstract
Ammonia, an end product from amino acid and nucleic acid metabolism, is highly toxic for most animals. This review will provide an update on nitrogen metabolism in terrestrial and aquatic insects with emphasis on ammonia generation and transport. Aspects that will be discussed include metabolic pathways of nitrogenous compounds, the origin of ammonia and other nitrogenous waste products, ammonia toxicity, putative ammonia transporters as well as ammonia transport processes known in insects. Ammonia transport mechanisms in the mosquito Aedes aegypti, the tobacco hornworm Manduca sexta and the locust Schistocerca gregaria will be discussed in detail while providing additional, novel data.
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Affiliation(s)
- Dirk Weihrauch
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada R3T2N2.
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