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Giraudo M, Hilliou F, Fricaux T, Audant P, Feyereisen R, Le Goff G. Cytochrome P450s from the fall armyworm (Spodoptera frugiperda): responses to plant allelochemicals and pesticides. Insect Mol Biol 2015; 24:115-28. [PMID: 25315858 DOI: 10.1111/imb.12140] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Spodoptera frugiperda is a polyphagous lepidopteran pest that encounters a wide range of toxic plant metabolites in its diet. The ability of this insect to adapt to its chemical environment might be explained by the action of major detoxification enzymes such as cytochrome P450s (or CYP). Forty-two sequences coding for P450s were identified and most of the transcripts were found to be expressed in the midgut, Malpighian tubules and fat body of S. frugiperda larvae. Relatively few P450s were expressed in the established cell line Sf9. In order to gain information on how these genes respond to different chemical compounds, larvae and Sf9 cells were exposed to plant secondary metabolites (indole, indole-3-carbinol, quercetin, 2-tridecanone and xanthotoxin), insecticides (deltamethrin, fipronil, methoprene, methoxyfenozide) or model inducers (clofibrate and phenobarbital). Several genes were induced by plant chemicals such as P450s from the 6B, 321A and 9A subfamilies. Only a few genes responded to insecticides, belonging principally to the CYP9A family. There was little overlap between the response in vivo measured in the midgut and the response in vitro in Sf9 cells. In addition, regulatory elements were detected in the promoter region of these genes. In conclusion, several P450s were identified that could potentially be involved in the adaptation of S. frugiperda to its chemical environment.
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Affiliation(s)
- M Giraudo
- INRA, UMR 1355, Institut Sophia Agrobiotech, Sophia-Antipolis, France; CNRS, UMR 7254, Sophia-Antipolis, France; Université de Nice Sophia Antipolis, Sophia-Antipolis, France; Environment Canada, Centre Saint-Laurent, Montreal, QC, Canada
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Isoe J, Scaraffia PY. Urea synthesis and excretion in Aedes aegypti mosquitoes are regulated by a unique cross-talk mechanism. PLoS One 2013; 8:e65393. [PMID: 23755226 PMCID: PMC3673916 DOI: 10.1371/journal.pone.0065393] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2013] [Accepted: 04/29/2013] [Indexed: 12/12/2022] Open
Abstract
Aedes aegypti mosquitoes do not have a typical functional urea cycle for ammonia disposal such as the one present in most terrestrial vertebrates. However, they can synthesize urea by two different pathways, argininolysis and uricolysis. We investigated how formation of urea by these two pathways is regulated in females of A. aegypti. The expression of arginase (AR) and urate oxidase (UO), either separately or simultaneously (ARUO) was silenced by RNAi. The amounts of several nitrogen compounds were quantified in excreta using mass spectrometry. Injection of mosquitoes with either dsRNA-AR or dsRNA-UO significantly decreased the expressions of AR or UO in the fat body (FB) and Malpighian tubules (MT). Surprisingly, the expression level of AR was increased when UO was silenced and vice versa, suggesting a cross-talk regulation between pathways. In agreement with these data, the amount of urea measured 48 h after blood feeding remained unchanged in those mosquitoes injected with dsRNA-AR or dsRNA-UO. However, allantoin significantly increased in the excreta of dsRNA-AR-injected females. The knockdown of ARUO mainly led to a decrease in urea and allantoin excretion, and an increase in arginine excretion. In addition, dsRNA-AR-injected mosquitoes treated with a specific nitric oxide synthase inhibitor showed an increase of UO expression in FB and MT and a significant increase in the excretion of nitrogen compounds. Interestingly, both a temporary delay in the digestion of a blood meal and a significant reduction in the expression of several genes involved in ammonia metabolism were observed in dsRNA-AR, UO or ARUO-injected females. These results reveal that urea synthesis and excretion in A. aegypti are tightly regulated by a unique cross-talk signaling mechanism. This process allows blood-fed mosquitoes to regulate the synthesis and/or excretion of nitrogen waste products, and avoid toxic effects that could result from a lethal concentration of ammonia in their tissues.
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Affiliation(s)
- Jun Isoe
- Department of Chemistry and Biochemistry, The Center for Insect Science, The University of Arizona, Tucson, Arizona, United States of America
| | - Patricia Y. Scaraffia
- Department of Chemistry and Biochemistry, The Center for Insect Science, The University of Arizona, Tucson, Arizona, United States of America
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de Azeredo-Oliveira MTV, da Silva TL, Mello MLS. Mg2+-dependent ATPase activity in Malpighian tubules of Triatoma infestans Klug. Micron 2011; 43:298-304. [PMID: 22024318 DOI: 10.1016/j.micron.2011.09.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 09/02/2011] [Accepted: 09/07/2011] [Indexed: 11/17/2022]
Abstract
Mg(2+)-dependent ATPases were investigated in Malpighian tubules of the blood-sucking insect, Triatoma infestans, with cytochemical procedures for light and electron microscopy. The aim was to establish patterns of enzyme occurrence in the blood-sucking insect under control rearing conditions for further comparisons with animals subjected to the action of stress factors. Enzyme activity was found in laminated "concretions" present in distal cells, in edges of urate crystals at the lumen of the proximal region of tubules, in the basement membrane of proximal cells, and variously distributed in plasmalemma invaginations of both distal and proximal cells. Presence of ATPases in the "concretions" and urate crystals is presumed to be due to engulfment of other ATPase-containing components during formation of these structures. Cytochemical reactivity in the basement membrane and plasmalemma invaginations is assumed to be involved with active transport of waste molecules from and to hemolymph and differs as a function of the Malpighian tubule region. This paper provides a basic understanding of the enzyme occurrence in the blood sucking insects, and can be used as a pattern for comparative means of the staining patterns among Triatominae species.
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Stevenson BJ, Bibby J, Pignatelli P, Muangnoicharoen S, O'Neill PM, Lian LY, Müller P, Nikou D, Steven A, Hemingway J, Sutcliffe MJ, Paine MJI. Cytochrome P450 6M2 from the malaria vector Anopheles gambiae metabolizes pyrethroids: Sequential metabolism of deltamethrin revealed. Insect Biochem Mol Biol 2011; 41:492-502. [PMID: 21324359 DOI: 10.1016/j.ibmb.2011.02.003] [Citation(s) in RCA: 178] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 02/03/2011] [Accepted: 02/07/2011] [Indexed: 05/30/2023]
Abstract
Resistance to pyrethroid insecticides in the malaria vector Anopheles gambiae is a major threat to malaria control programmes. Cytochome P450-mediated detoxification is an important resistance mechanism. CYP6M2 is over-expressed in wild populations of permethrin resistant A. gambiae but its role in detoxification is not clear. CYP6M2 was expressed in Escherichia coli and a structural model was produced to examine its role in pyrethroid metabolism. Both permethrin and deltamethrin were metabolized. Rates were enhanced by A. gambiae cytochrome b(5) with kinetic parameters of K(M)=11±1μM and k(cat)=6.1±0.4 per min for permethrin (1:1 cis-trans) and K(M)=2.0±0.3μM and k(cat)=1.2±0.1 per min for deltamethrin. Mass spectrometry and NMR analysis identified 4'-hydroxy deltamethrin and hydroxymethyl deltamethrin as major and minor deltamethrin metabolites respectively. Secondary breakdown products included cyano(3-hydroxyphenyl)methyl deltamethrate and deltamethric acid. CYP6M2 was most highly transcribed in the midgut and Malpighian tubules of adult A. gambiae, consistent with a role in detoxification. Our data indicates that CYP6M2 plays an important role in metabolic resistance to pyrethroids and thus an important target for the design of new tools to combat malaria.
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Secca T, Sciaccaluga M, Marra A, Barberini L, Bicchierai MC. Biochemical activity and multiple locations of particulate guanylate cyclase in Rhyacophila dorsalis acutidens (Insecta: Trichoptera) provide insights into the cGMP signalling pathway in Malpighian tubules. J Insect Physiol 2011; 57:521-528. [PMID: 21315075 DOI: 10.1016/j.jinsphys.2011.02.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Revised: 01/31/2011] [Accepted: 02/02/2011] [Indexed: 05/30/2023]
Abstract
In insect renal physiology, cGMP and cAMP have important regulatory roles. In Drosophila melanogaster, considered a good model for molecular physiology studies, and in other insects, cGMP and cAMP act as signalling molecules in the Malpighian tubules (MTs). However, many questions related to cyclic nucleotide functions are unsolved in principal cells (PC) and stellate cells (SC), the two cell types that compose the MT. In PC, despite the large body of information available on soluble guanylate cyclase (sGC) in the cGMP pathway, the functional circuit of particulate guanylate cyclase (pGC) remains obscure. In SC, on the other side, the synthesis and physiological role of the cGMP are still unknown. Our biochemical data regarding the presence of cyclic nucleotides in the MTs of Rhyacophila dorsalis acutidens revealed a cGMP level above the 50%, in comparison with the cAMP. The specific activity values for the membrane-bound guanylate cyclase were also recorded, implying that, besides the sGC, pGC is a physiologically relevant source of cGMP in MTs. Cytochemical studies showed ultrastructurally that there was a great deal of pGC on the basolateral membranes of both the principal and stellate cells. In addition, pGC was also detected in the contact zone between the two cell types and in the apical microvillar region of the stellate cells bordering the tubule lumen. The pGC signal is so well represented in PC and, unexpectedly in SC of MTs, that it is possible to hypothesize the existence of still uncharacterized physiological processes regulated by the pGC-cGMP system.
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Affiliation(s)
- T Secca
- Section of Cellular and Molecular Biology, Department of Cellular and Environmental Biology, University of Perugia, 06123 Perugia, Italy.
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Terhzaz S, Finlayson AJ, Stirrat L, Yang J, Tricoire H, Woods DJ, Dow JAT, Davies SA. Cell-specific inositol 1,4,5 trisphosphate 3-kinase mediates epithelial cell apoptosis in response to oxidative stress in Drosophila. Cell Signal 2010; 22:737-48. [PMID: 20060894 DOI: 10.1016/j.cellsig.2009.12.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Accepted: 12/24/2009] [Indexed: 11/18/2022]
Abstract
Organismal stress responses to oxidative stress are relevant to ageing and disease and involve key cell-/tissue-specific signal transduction mechanisms. Using Drosophila, an established in vivo model for stress studies, we show that cell-specific inositol phosphate signalling specifically via inositol 1,4,5 trisphosphate 3-kinase (InsP(3) 3-K, IP(3)K), negatively regulates organismal responses to oxidative stress. We demonstrate that the Drosophila Malpighian tubule (equivalent to vertebrate kidney and liver) is a key epithelial sensor for organismal oxidative stress responses: precise targeting of either gain-of-function constructs of Drosophila IP(3)Ks (IP(3)K-1 and IP(3)K-2), or loss-of-function (RNAi) constructs to only one cell type in tubule reversibly modulates survival of stress-challenged adult flies. In vivo, targeted IP(3)K-1 directly increases H(2)O(2) production, pro-apoptotic caspase-9 activity and mitochondrial membrane potential. The mitochondrial calcium load in tubule principal cells-assessed by luminescent and fluorescent genetically-encoded mitochondrial calcium reporters-is significantly increased by IP(3)K-1 under oxidative stress conditions, leading to apoptosis. The Drosophila orthologues of human apoptotic bcl-2 genes include debcl and buffy. Oxidative stress challenge does not modulate gene expression of either debcl or buffy in tubules; and altered debcl expression does not influence survival rates under oxidative stress challenge. Finally, targeted over-expression of either debcl or buffy to tubule principal cells does not impact on tubule caspase-9 activity. Thus, IP(3)K-1 modulates epithelial cell apoptosis without involvement of bcl-2-type proteins.
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Patrick ML, Aimanova K, Sanders HR, Gill SS. P-type Na+/K+-ATPase and V-type H+-ATPase expression patterns in the osmoregulatory organs of larval and adult mosquitoAedes aegypti. J Exp Biol 2006; 209:4638-51. [PMID: 17114398 DOI: 10.1242/jeb.02551] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
SUMMARYThis study describes the expression patterns of P-type Na+/K+-ATPase and V-type H+-ATPase in the larval and adult forms of the mosquito Aedes aegypti and provides insight into their relative importance in ion transport function of key osmoregulatory organs. RT-PCR assays indicate that, at the level of the gene,both ATPases are expressed in all of the osmoregulatory tissues of larvae(midgut, Malpighian tubules, rectum and anal papillae) and adults (stomach,Malpighian tubules, anterior hindgut and rectum). Immunohistochemical studies determined that both ATPases are present in high levels in all the relevant organs, with the exception of the larval rectum (P-type Na+/K+-ATPase only). In larval gastric caeca, ATPase location corresponds to the secretory (basal P-type Na+/K+-ATPase, apical V-type H+-ATPase) and ion-transporting (V-type H+-ATPase on both membranes) regions as previously described. The two ATPases switch membrane location along the length of the larval midgut, indicating three possible regionalizations,whereas the adult stomach has uniform expression of basolateral P-type Na+/K+-ATPase and apical V-type H+-ATPase in each cell. In both larval and adult Malpighian tubules, the distal principal cells exhibit high expression levels of V-type H+-ATPase (apically and cytoplasmically) whereas P-type Na+/K+-ATPase is highly expressed in stellate cells found only in the distal two-thirds of each tubule. By contrast, the proximal principal cells express both P-type Na+/K+-ATPase (basal) and V-type H+-ATPase(apical). These results suggest a functional segregation along the length of the Malpighian tubules based on cell type and region. P-type Na+/K+-ATPase is the only pump apparent in the larval rectum whereas in the larval anal papillae and the adult hindgut (including the anterior hindgut and rectum with rectal pads), P-type Na+/K+-ATPase and V-type H+-ATPase localize to the basal and apical membranes, respectively. We discuss our findings in light of previous physiological and morphological studies and re-examine our current models of ion transport in these two developmental stages of mosquitoes that cope with disparate osmoregulatory challenges.
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Affiliation(s)
- Marjorie L Patrick
- Department of Cell Biology and Neuroscience, University of California, Riverside, CA 92521-0146, USA.
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Southall TD, Terhzaz S, Cabrero P, Chintapalli VR, Evans JM, Dow JAT, Davies SA. Novel subcellular locations and functions for secretory pathway Ca2+/Mn2+-ATPases. Physiol Genomics 2006; 26:35-45. [PMID: 16609144 DOI: 10.1152/physiolgenomics.00038.2006] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Secretory pathway Ca2+/Mn2+-ATPases (SPCAs) are important for maintenance of cellular Ca2+and Mn2+homeostasis, and, to date, all SPCAs have been found to localize to the Golgi apparatus. The single Drosophila SPCA gene ( SPoCk) was identified by an in silico screen for novel Ca2+-ATPases. It encoded three SPoCk isoforms with novel, distinct subcellular specificities in the endoplasmic reticulum (ER) and peroxisomes in addition to the Golgi. Furthermore, expression of the peroxisome-associated SPoCk isoform was sexually dimorphic. Overexpression of organelle-specific SPoCk isoforms impacted on cytosolic Ca2+handling in both cultured Drosophila cells and a transporting epithelium, the Drosophila Malpighian (renal) tubule. Specifically, the ER isoform impacted on inositol ( 1 , 4 , 5 )-trisphosphate-mediated Ca2+signaling and the Golgi isoform impacted on diuresis, whereas the peroxisome isoform colocalized with Ca2+“spherites” and impacted on calcium storage and transport. Interfering RNA directed against the common exons of the three SPoCk isoforms resulted in aberrant Ca2+signaling and abolished neuropeptide-stimulated diuresis by the tubule. SPoCk thus contributed to both of the contrasting requirements for Ca2+in transporting epithelia: to transport or store Ca2+in bulk without compromising its use as a signal.
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Affiliation(s)
- Tony D Southall
- Division of Molecular Genetics, Anderson College Complex, University of Glasgow, Glasgow, United Kingdom
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Abstract
cGMP was first discovered in urine, demonstrating that kidney cells extrude this cyclic nucleotide. Drosophila Malpighian tubules provide a model renal system in which a homologue of mammalian PDE (phosphodiesterase) 6 is expressed. In humans, this cG-PDE (cGMP-specific PDE) is specifically expressed in the retinal system, where it controls visual signal transduction. In order to gain insight into the functional role of DmPDE6 (Drosophila PDE6-like enzyme) in epithelial function, we generated transgenic animals with targeted expression of DmPDE6 to tubule Type I (principal) cells. This revealed localization of DmPDE6 primarily at the apical membranes. As expected, overexpression of DmPDE6 resulted in elevated cG-PDE activity and decreased tubule cGMP content. However, such targeted overexpression of DmPDE6 creates a novel phenotype that manifests itself in inhibition of the active transport and efflux of cGMP by tubules. This effect is specific to DmPDE6 action, as no effect on cGMP transport is observed in tubules from a bovine PDE5 transgenic line which display reduced rates of fluid secretion, an effect not seen in DmPDE6 transgenic animals. Specific ablation of DmPDE6 in tubule principal cells, via expression of a targeted DmPDE6 RNAi (RNA interference) transgene, conferred increased active transport of cGMP, confirming a direct role for DmPDE6 in regulating cGMP transport in tubule principal cells. Pharmacological inhibition of DmPDE6 in wild-type tubules using the cG-PDE inhibitor, zaprinast, similarly results in stimulated cGMP transport. We provide the first demonstration of a novel role for a cG-PDE in modulating cGMP transport and efflux.
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Affiliation(s)
- Jonathan P Day
- Institute of Biomedical and Life Sciences, Division of Molecular Genetics, University of Glasgow, Glasgow G11 6NU, UK.
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Thomas J, Rylett C, Carhan A, Bland N, Bingham R, Shirras A, Turner A, Isaac R. Drosophila melanogaster NEP2 is a new soluble member of the neprilysin family of endopeptidases with implications for reproduction and renal function. Biochem J 2005; 386:357-66. [PMID: 15554877 PMCID: PMC1134801 DOI: 10.1042/bj20041753] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The mammalian neprilysin (NEP) family members are typically type II membrane endopeptidases responsible for the activation/inactivation of neuropeptides and peptide hormones. Differences in substrate specificity and subcellular localization of the seven mammalian NEPs contribute to their functional diversity. The sequencing of the Drosophila melanogaster genome has revealed a large expansion of this gene family, resulting in over 20 fly NEP-like genes, suggesting even greater diversity in structure and function than seen in mammals. We now report that one of these genes (Nep2) codes for a secreted endopeptidase with a highly restricted pattern of expression. D. melanogaster NEP2 is expressed in the specialized stellate cells of the renal tubules and in the cyst cells that surround the elongating spermatid bundles in adult testis, suggesting roles for the peptidase in renal function and in spermatogenesis. D. melanogaster NEP2 was found in vesicle-like structures in the syncytial cytoplasm of the spermatid bundles, suggesting that the protein was acquired by endocytosis of protein secreted from the cyst cells. Expression of NEP2 cDNA in D. melanogaster S2 cells confirmed that the peptidase is secreted and is only weakly inhibited by thiorphan, a potent inhibitor of human NEP. D. melanogaster NEP2 also differs from human NEP in the manner in which the peptidase cleaves the tachykinin, GPSGFYGVR-amide. Molecular modelling suggests that there are important structural differences between D. melanogaster NEP2 and human NEP in the S1' and S2' ligand-binding subsites, which might explain the observed differences in inhibitor and substrate specificities. A soluble isoform of a mouse NEP-like peptidase is strongly expressed in spermatids, suggesting an evolutionarily conserved role for a soluble endopeptidase in spermatogenesis.
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Affiliation(s)
- Josie E. Thomas
- *Molecular and Cellular Biology Research Group, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, U.K
| | - Caroline M. Rylett
- *Molecular and Cellular Biology Research Group, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, U.K
| | - Ahmet Carhan
- †Department of Biological Sciences, University of Lancaster, Lancaster LA1 4YQ, U.K
| | - Nicholas D. Bland
- *Molecular and Cellular Biology Research Group, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, U.K
| | - Richard J. Bingham
- *Molecular and Cellular Biology Research Group, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, U.K
| | - Alan D. Shirras
- †Department of Biological Sciences, University of Lancaster, Lancaster LA1 4YQ, U.K
| | - Anthony J. Turner
- *Molecular and Cellular Biology Research Group, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, U.K
| | - R. Elwyn Isaac
- *Molecular and Cellular Biology Research Group, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, U.K
- To whom correspondence should be addressed (email )
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MacPherson MR, Lohmann SM, Davies SA. Analysis of Drosophila cGMP-dependent Protein Kinases and Assessment of Their in Vivo Roles by Targeted Expression in a Renal Transporting Epithelium. J Biol Chem 2004; 279:40026-34. [PMID: 15218025 DOI: 10.1074/jbc.m405619200] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
cGMP-dependent protein kinase (cGK) forms encoded by the dg2 (for) gene are implicated in behavior and epithelial transport in Drosophila melanogaster. Here, we provide the first biochemical characterization and cellular localization of cGKs encoded by the major transcripts of dg2: dg2P1 and dg2P2. cGMP stimulates kinase activity of DG2P1 (EC(50): 0.13 +/- 0.039 microm) and DG2P2 (EC(50): 0.32 +/- 0.14 microm) in Malpighian tubule and S2 cell extracts. DG2P1 and DG2P2 are magnesium-requiring enzymes and were inhibited by 10 and 100 microm of a cGK inhibitor, 8-(4-chlorophenylthio)guanosine-3',5'-cyclic monophosphorothioate, Rp isomer; whereas DG1, the cGK encoded by the D. melanogaster dg1 gene, was unaffected. DG2P1 and DG2P2 were localized in the plasma membrane in S2 cells, whereas DG1 was localized in the cytosol. The D. melanogaster fluid-transporting Malpighian tubule was used as an organotypic model to analyze cGK localization and function in vivo. Targeted expression of DG2P2, DG2P1, and DG1 in tubule cells via the UAS/GAL4 system in transgenic flies revealed differential localization of all three cGKs in vivo: DG2P2 expression at the apical membrane; DG2P1 expression at both the apical and basolateral membranes; and DG1 expression at the basolateral membrane and in the cytosol. Transgenic tubules for all three cGKs displayed enhanced cGK activity compared with wild-type tubules. The physiological impact of targeted expression of individual cGKs in tubule principal cells was assessed by measuring basal and stimulated rates of fluid transport. DG1 expression greatly enhanced fluid transport by the tubule in response to exogenous cGMP, whereas DG2P2 expression significantly increased fluid transport in response to the nitridergic neuropeptide, capa-1. Thus, dg2-encoded proteins are bona fide cGKs, which have differential roles in epithelial fluid transport, as assessed by in vivo studies. Furthermore, a novel epithelial role is suggested for DG1, which is considerably more responsive to cGMP than to capa-1 stimulation.
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Affiliation(s)
- Matthew R MacPherson
- Institute of Biomedical and Life Sciences, Division of Molecular Genetics, University of Glasgow, Anderson College, Dumbarton Rd., Glasgow G11 6NU, United Kingdom
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Ferraro RB, Sousa JL, Cunha RDC, Meyer-Fernandes JR. Characterization of an ecto-phosphatase activity in malpighian tubules of hematophagous bug Rhodnius prolixus. Arch Insect Biochem Physiol 2004; 57:40-49. [PMID: 15352154 DOI: 10.1002/arch.20013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We have characterized a phosphatase activity present on the external surface of intact Malpighian tubules in Rhodnius prolixus. This phosphatase hydrolyses the substrate p-nitrophenyl phosphate at a rate of 3.38 +/- 0.07 nmol Pi x mg(-1) x min(-1). Phosphatase activity decreased with the increase of the pH from 6.4 to 7.6 pH, a range in which tubules cellular integrity was maintained for at least 1 h. Classical inhibitors of acid phosphatase, such as ammonium molybdate, fluoride, vanadate, mpV-PIC, and bpV-PHEN, caused different patters of inhibition. The ecto-phosphatase present an apparent Km of 1.67 +/- 0.34 mM and Vmax of 5.71 +/- 0.37 nmol Pi x mg(-1) x min(-1) for p-NPP. Zinc chloride inhibited 78.2% of ecto-phosphatase activity, with Ki of 0.35 mM. Such inhibition was reversed by incubation with cysteine and GSH, but not DTT, serine, and GSSG, showing that cysteine residues are important for enzymatic activity. Phosphatase activity increased 141% three days after blood meal, and returned to basal levels 2 days later. These results suggest that ecto-phosphatase activity could be involved in a diuretic mechanism, essential in the initial days after a blood meal for the control of Rhodnius homeostasis.
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Affiliation(s)
- Rodrigo B Ferraro
- Departamento de Bioquímica Médica, ICB, Universidade Federal do Rio de Janeiro, UFRJ, Cidade Universitária, Ilha do Fundão, 21941-590, Rio de Janeiro, RJ, Brazil
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Broderick KE, Kean L, Dow JAT, Pyne NJ, Davies SA. Ectopic expression of bovine type 5 phosphodiesterase confers a renal phenotype in Drosophila. J Biol Chem 2003; 279:8159-68. [PMID: 14662775 DOI: 10.1074/jbc.m304679200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
cGMP signaling regulates epithelial fluid transport by Drosophila Malpighian (renal) tubules. In order to directly evaluate the importance of cGMP-degrading phosphodiesterases (PDEs) in epithelial transport, bovine PDE5 (a bona fide cGMP-PDE), was ectopically expressed in vivo. Transgenic UAS-PDE5 Drosophila were generated, and PDE5 expression was driven in specified tubule cells in vivo by cell-specific GAL4 drivers. Targeted expression was verified by PCR and Western blotting. Immunolocalization of PDE5 in tubule confirmed specificity of expression and demonstrated localization to the apical plasma membrane. GAL4/UAS-PDE5 tubules exhibit increased cG-PDE activity and reduced basal cGMP levels compared with control lines. We show that wild-type and control tubules are sensitive to the PDE5-specific inhibitor sildenafil and that GAL4/UAS-PDE5 tubules display enhanced sensitivity to sildenafil, compared with controls. cGMP content in GAL4/UAS-PDE5 tubules is restored to control levels by treatment with sildenafil. Thus bovine PDE5 retains cGMP-degrading activity and inhibitor sensitivity when expressed in Drosophila. Expression of PDE5 in tubule principal cells results in an epithelial phenotype, reducing rates of basal and cGMP-/Cardioaccelatory peptide(2b)(CAP(2b))-stimulated fluid transport. Furthermore, inhibition of PDE5 activity by sildenafil restores basal and cGMP-stimulated fluid transport rates to control levels. However, corticotrophin releasing factor-like-stimulated transport, which is activated by cAMP signaling, was unaffected, confirming that only cGMP-stimulated signaling events in tubule are compromised by overexpression of PDE5. Successful ectopic expression of a vertebrate cG-PDE in Drosophila has shown that cG-PDE has a critical role in tubule function in vivo and that cG-PDE function is conserved across evolution. The transgene also provides a generic tool for the analysis of cGMP signaling in Drosophila.
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Affiliation(s)
- Kate E Broderick
- Institute of Biomedical and Life Sciences, Division of Molecular Genetics, University of Glasgow, Glasgow G11 6NU, USA
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14
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Broderick KE, MacPherson MR, Regulski M, Tully T, Dow JAT, Davies SA. Interactions between epithelial nitric oxide signaling and phosphodiesterase activity in Drosophila. Am J Physiol Cell Physiol 2003; 285:C1207-18. [PMID: 12853288 DOI: 10.1152/ajpcell.00123.2003] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Signaling by nitric oxide (NO) and guanosine 3',5'-cyclic monophosphate (cGMP) modulates fluid transport in Drosophila melanogaster. Expression of an inducible transgene encoding Drosophila NO synthase (dNOS) increases both NOS activity in Malpighian (renal) tubules and DNOS protein in both type I (principal) and type II (stellate) cells. However, cGMP content is increased only in principal cells. DNOS overexpression results in elevated basal rates of fluid transport in the presence of the phosphodiesterase (PDE) inhibitor, Zaprinast. Direct assay of tubule cGMP-hydrolyzing phosphodiesterase (cG-PDE) activity in wild-type and dNOS transgenic lines shows that cG-PDE activity is Zaprinast sensitive and is elevated upon dNOS induction. Zaprinast treatment increases cGMP content in tubules, particularly at the apical regions of principal cells, suggesting localization of Zaprinast-sensitive cG-PDE to these areas. Potential cross talk between activated NO/cGMP and calcium signaling was assessed in vivo with a targeted aequorin transgene. Activated DNOS signaling alone does not modify either neuropeptide (CAP2b)- or cGMP-induced increases in cytosolic calcium levels. However, in the presence of Zaprinast, both CAP2b-and cGMP-stimulated calcium levels are potentiated upon DNOS overexpression. Use of the calcium channel blocker, verapamil, abolishes the Zaprinast-induced transport phenotype in dNOS-overexpressing tubules. Molecular genetic intervention in the NO/cGMP signaling pathway has uncovered a pivotal role for cell-specific cG-PDE in regulating the poise of the fluid transporting Malpighian tubule via direct effects on intracellular cGMP concentration and localization and via interactions with calcium signaling mechanisms.
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Affiliation(s)
- Kate E Broderick
- Institute of Biomedical and Life Sciences, Division of Molecular Genetics, University of Glasgow, Glasgow G11 6NU, Scotland, UK
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15
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Abstract
The V-type H(+)-ATPase is thought to provide the driving force for transepithelial electrolyte and fluid secretion in Malpighian tubules. To confirm the presence of this proton pump in Malpighian tubules of the yellow fever mosquito Aedes aegypti, we used several antibodies raised against the V-type H(+)-ATPase of Manduca sexta. Western blot analysis confirmed the presence of the V-type H(+)-ATPase in Malpighian tubules of Aedes aegypti. In situ immunostaining identified the V-type H(+)-ATPase at the apical membrane of the mitochondrion-rich brush border of principal cells. The V-type H(+)-ATPase was not found in stellate cells. Measurements of ATPase activity revealed that bafilomycin-sensitive and NO(3)(-)-sensitive ATPase activity accounted for 50-60% of total ATPase activity in crude extracts of Malpighian tubules. No significant ouabain- or vanadate-sensitive Na(+)/K(+)-ATPase activity was detected. These results support the conclusion reached previously in electrophysiological studies that the mechanisms for transepithelial electrolyte secretion in the Aedes Malpighian tubules rely on the V-type H(+)-ATPase as the principal energizer of epithelial transport. Measures of transepithelial Na(+) and K(+) secretion and estimates of the H(+) flux mediated by the V-type H(+)-ATPase suggest a 1:1 stoichiometry for Na(+)/H(+) and K(+)/H(+) exchange transport across the apical membrane.
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Affiliation(s)
- Xing-He Weng
- Department of Biomedical Sciences, Cornell University, Ithaca, NY 14853, USA
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16
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Winter J, Eckerskorn C, Waditschatka R, Kayser H. A microsomal ecdysone-binding cytochrome P450 from the insect Locusta migratoria purified by sequential use of type-II and type-I ligands. Biol Chem 2001; 382:1541-9. [PMID: 11767943 DOI: 10.1515/bc.2001.188] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A dual-affinity method was established to purify, for the first time, a microsomal ecdysone-binding cytochrome P450 protein from locust Malpighian tubules. This method involved, after prepurification on omega-octylamino-agarose and hydroxylapatite, binding of cytochrome P450 to an immobilized triazole-based general P450 inhibitor (type-II ligand) followed by elution with the substrate ecdysone (type-I ligand) of the bound cytochrome. The isolated material showed a typical cytochrome P450 spectrum, a specific heme content of 13 nmol/mg protein, and a prominent protein of about 60 kDa on SDS-PAGE. Based on a tryptic undecapeptide sequence the isolated protein may be identical to CYP6H1, a putative ecdysone 20-monooxygenase recently cloned from the same tissue. Ecdysone 20-monooxygenase activity could be partially reconstituted from microsomal detergent extracts, when supplemented with purified bovine cytochrome P450 reductase and detergent-extracted microsomes; reconstitution was not successful with any chromatographic fraction, however. Therefore, purification of the locust cytochrome P450 was monitored by ecdysone-induced type-I difference spectra, whenever applicable, in addition to carbon monoxide spectra. Affinity columns with matrix-bound diethylstilbestrol and testosterone 3-thiosemicarbazone, but not with the 17beta-hemisuccinate, yielded elution profiles with ecdysone that were comparable to those of the triazole matrix. The concept of dual-affinity chromatography described here may be generally applicable to the isolation of cytochromes P450.
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Affiliation(s)
- J Winter
- Syngenta Crop Protection AG, Basel, Switzerland
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17
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Caruso-Neves C, Silva IV, Morales MM, Lopes AG. Cytoskeleton elements mediate the inhibition of the (Na++K+)atpase activity by PKC in Rhodnius prolixus malpighian tubules during hyperosmotic shock. Arch Insect Biochem Physiol 2001; 48:81-88. [PMID: 11568967 DOI: 10.1002/arch.1060] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In a previous paper, we observed that the specific activity of (Na++K+)ATPase of the isolated Malpighian tubules from Rhodnius prolixus is inhibited by protein kinase C (PKC) during hyperosmotic shock [Arenstein et al., J Membr Biol 146:47-57 [1995]; Caruso-Neves et al., Z Naturforsch 53c:911-917 [1998]). In the present paper, we study the involvement of the cytoskeleton in this process using isolated Malpighian tubules of Rhodnius prolixus. We observed that pre-incubation of the Malpighian tubule cells in hyperosmotic media decreases the specific activity of (Na++K+)ATPase by 90%. This effect was completely reversed when colchicine, which disrupts microtubules, or cytochalasin B, an inhibitor of actin microfilament polymerization, were added to the media in a dose-dependent manner. The maximal reversion was obtained with colchicine 7.0 microM or cytochalasin B 5.0 microM. The simultaneous addition of sphingosine 50 ng/mL, an inhibitor of PKC, to 10 microM colchicine or 5 microM cytochalasin B, in hyperosmotic media, did not change the stimulatory effect of these drugs on the specific activity of (Na++K+)ATPase. On the other hand, the co-incubation of TPA 20 ng/mL, an activator of PKC, to colchicine or cytochalasin B within hyperosmotic media, abolished the stimulatory effect of these drugs on the specific activity of (Na++K+)ATPase to a similar extent as hyperosmotic shock. These results suggest that inhibition of the (Na++K+)ATPase of the isolated Malpighian tubules from Rhodnius prolixus by PKC during hyperosmotic shock is mediated by cytoskeletal elements.
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Affiliation(s)
- C Caruso-Neves
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Brazil
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18
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Abstract
The Ussing model has long provided the conceptual foundation for understanding epithelial transport mechanisms energized by the Na(+)-K(+)-ATPase. Plasma membranes may also use the vacuolar (V-type) H(+)-ATPase as the primary energy source of membrane and epithelial transport. A pure electrogenic pump, the V-type H(+)-ATPase energizes not only membranes it inhabits but also other transport pathways via electrical coupling.
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Affiliation(s)
- K W Beyenbach
- Department of Biomedical Sciences, Cornell University, Ithaca, New York 14853, USA.
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Coast GM, Webster SG, Schegg KM, Tobe SS, Schooley DA. The Drosophila melanogaster homologue of an insect calcitonin-like diuretic peptide stimulates V-ATPase activity in fruit fly Malpighian tubules. J Exp Biol 2001; 204:1795-804. [PMID: 11316500 DOI: 10.1242/jeb.204.10.1795] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The Drosophila melanogaster homologue of an insect calcitonin-like diuretic hormone was identified in a BLAST search of the Drosophila genome database. The predicted 31-residue amidated peptide (D. melanogaster DH(31); Drome-DH(31)) was synthesised and tested for activity on fruit fly Malpighian tubules. It increases tubule secretion by approximately 35 % of the response obtained with a myokinin from the housefly Musca domestica (muscakinin; Musdo-K) and has an EC(50) of 4.3 nmol l(−)(1). The diuretic activities of Drome-DH(31) and Musdo-K were additive when tested at threshold and supra-maximal concentrations, which suggests that they target different transport processes. In support of this, Drome-DH(31) increased the rate of secretion by tubules held in bathing fluid with a reduced Cl(−) concentration, whereas Musdo-K did so only in the presence of Drome-DH(31). Stimulation with Drome-DH(31) increased the lumen-positive transepithelial potential in the main secretory segment of the tubule. This was attributed to activation of an apical electrogenic proton-translocating V-ATPase in principal cells, since it was associated with hyperpolarisation of the apical membrane potential and acidification of secreted urine by 0.25 pH units. Exogenous 8-bromo-cyclic AMP and cyclic GMP increased tubule secretion to the same extent as Drome-DH(31) and, when tested together with the diuretic peptide, their activities were not additive. Stimulation with Drome-DH(31) resulted in a dose-dependent increase in cyclic AMP production by tubules incubated in saline containing 0.5 mmol l(−)(1) 3-isobutyl-1-methylxanthine, whereas cyclic GMP production was unchanged. Taken together, the data are consistent with Drome-DH(31) activating an apical membrane V-ATPase via cyclic AMP. Since the K(+) concentration of the secreted urine was unchanged, it is likely that Drome-DH(31) has an equal effect on K(+) and Na(+) entry across the basolateral membrane.
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Affiliation(s)
- G M Coast
- Department of Biology, Birkbeck College, Malet Street, London WC1E 7HX, UK.
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20
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Yi SX, Adams TS. Age- and diapause-related acid and alkaline phosphatase activities in the intestine and malpighian tubules of the Colorado potato beetle, Leptinotarsa decemlineata (Say). Arch Insect Biochem Physiol 2001; 46:152-163. [PMID: 11276072 DOI: 10.1002/arch.1025] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Specific activities for soluble (s) and membrane (m)-bound acid (ACP) and alkaline phosphatases (ALP) were determined in the midgut, hindgut, and Malpighian tubules for developing, prediapausing, and diapausing adult Colorado potato beetles, Leptinotarsa decemlineata (Say). High ACP activities were found in the hindgut and Malpighian tubules while high ALP activities were found in the Malpighian tubules. Variation in both ACP and ALP activities in each tissue reflects fluctuation in protein synthesis and secretion involved with digestion, excretion, and other unknown functions. Phosphatase activities in the tissues examined show the dynamic nature of diapause in this insect. Diapausing beetles showed increases in phosphatase activity after hormone treatments. JHA treatments increased s-ACP and m-ACP activities in all tissues but 20-HE did not increase activity in any tissue. Allatotropin tended to mimic the effects of JHA treatment. The s-ALP activity was also increased in all tissues whereas m-ALP was increased in the midgut and hindgut by JHA treatment. Malpighian tubule m-ALP activity was only increased by 20-HE treatments. Allatotropin was not as effective in increasing ALP activities as it was with ACP activities.
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Affiliation(s)
- S X Yi
- Biosciences Research Laboratory, USDA-ARS, State University Station, Fargo, North Dakota 58105-5674, USA
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21
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Abstract
Malpighian tubule of Rhodnius sp. express two sodium pumps: the classical ouabain-sensitive (Na+ + K+)ATPase and an ouabain-insensitive, furosemide-sensitive Na+-ATPase. In insects, 5-hydroxitryptamine is a diuretic hormone released during meals. It inhibits the (Na+ + K+)ATPase and Na+ -ATPase activities indicating that these enzymes are involved in fluid secretion. Furthermore, in Rhodnius neglectus, proximal cells of Malpighian tubule exposed to hyperosmotic medium, regulate their volume through a mechanism called regulatory volume increase. This regulatory response involves inhibition of the (Na+ + K+)ATPase activity that could lead to accumulation of active osmotic solute inside the cell, influx of water and return to the normal cell volume. Adenosine, a compound produced in stress conditions, also inhibits the (Na+ + K+)ATPase activity. Taken together these data indicate that (Na+ + K+)ATPase is a target of the regulatory mechanisms of water and ions transport responsible for homeostasis in Rhodnius sp.
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Affiliation(s)
- C Caruso-Neves
- Laboratório de Fisiologia Renal, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21949-900, Brasil
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22
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Beyenbach KW, Pannabecker TL, Nagel W. Central role of the apical membrane H+-ATPase in electrogenesis and epithelial transport in Malpighian tubules. J Exp Biol 2000; 203:1459-68. [PMID: 10751161 DOI: 10.1242/jeb.203.9.1459] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The effects of bafilomycin A(1), a blocker of V-type H(+)-ATPases, were investigated in Malpighian tubules of Aedes aegypti. Bafilomycin A(1) reduced rates of transepithelial fluid secretion and the virtual short-circuit current (vI(sc)) with an IC(50) of approximately 5 micromol l(−)(1). As vI(sc) decreased, the electrical resistance increased across the whole epithelium and across the apical membrane, indicating effects on electroconductive pathways. Bafilomycin A(1) had no effect when applied from the tubule lumen, pointing to the relative impermeability of the apical membrane to bafilomycin A(1). Thus, bafilomycin A(1) must take a cytoplasmic route to its blocking site in the proton channel of the H(+)-ATPase located in the apical membrane of principal cells. The inhibitory effects of bafilomycin A(1) were qualitatively similar to those of dinitrophenol in that voltages across the epithelium (V(t)), the basolateral membrane (V(bl)) and the apical membrane (V(a)) depolarized towards zero in parallel. Moreover, V(bl)always tracked V(a), indicating electrical coupling between the two membranes through the shunt. Electrical coupling allows the H(+)-ATPase to energize not only the apical membrane, but also the basolateral membrane. Furthermore, electrical coupling offers a balance between electroconductive entry of cations across the basolateral membrane and extrusion across the apical membrane to support steady-state conditions during transepithelial transport.
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Affiliation(s)
- K W Beyenbach
- Department of Biomedical Sciences, VRT 8014, Cornell University, Ithaca, NY 14853, USA.
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23
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Caruso-Neves C, Monteiro SO, de Oliveira CF, Filho CC, Lopes AG. Adenosine modulates the (Na(+)+K(+))ATPase activity in malpighian tubules isolated from Rhodnius prolixus. Arch Insect Biochem Physiol 2000; 43:72-77. [PMID: 10644971 DOI: 10.1002/(sici)1520-6327(200002)43:2<72::aid-arch3>3.0.co;2-e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The role of adenosine on regulation of the (Na(+)+K(+))ATPase activity present in the Malpighian tubules isolated from Rhodnius prolixus was investigated. Adenosine decreases the (Na(+)+K(+)) ATPase specific activity by 88%, in a dose-dependent manner, with maximal effect at a concentration of 10(-9) M. This effect was mimicked by N(6)-cyclohexyladenosine (CHA) at 10(-8) M, an agonist for A(1) adenosine receptor, and was reversed by 10(-9) M 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), an antagonist for A(1) adenosine receptor. On the other hand, 5'-N-ethyl-carboxamide adenosine (NECA), an agonist for A(2) adenosine receptor, used in the range of 10(-9)-10(-5) M, did not change the (Na(+)+K(+))ATPase specific activity. In the same way, 10(-8) M 3, 7-dimethyl-1-propargylxanthine (DMPX), an antagonist for A(2) adenosine receptor, did not modify the inhibitory effect of adenosine. These data suggest that the inhibitory effect of adenosine on the (Na(+)+K(+))ATPase specific activity present in Malpighian tubules from Rhodnius prolixus is mediated by A(1) adenosine receptor activation. Arch.
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Affiliation(s)
- C Caruso-Neves
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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24
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Abstract
Plasma membrane V-ATPase isolated from midgut and Malpighian tubules of the tobacco hornworm, Manduca sexta, contains a novel prominent 20-kDa polypeptide. Based on N-terminal protein sequencing, we cloned a corresponding cDNA. The deduced hydrophobic protein consisted of 88 amino acids with a molecular mass of only 9.7 kDa. Immunoblots of the recombinant 9.7-kDa polypeptide, using a monoclonal anti- body to the 20-kDa polypeptide, confirmed that the correct cDNA had been cloned. The 20-kDa polypeptide is glycosylated, as deduced from lectin staining. Treatment with N-glycosidase A resulted in the appearance of two additional protein bands of 16 and 10 kDa which both were immunoreactive to the 20-kDa polypeptide-specific monoclonal antibody. Thus, extensive N-glycosylation of the novel Vo subunit M9.7 accounts for half of its molecular mass observed in SDS-polyacrylamide gel electrophoresis. M9.7 exhibits some similarities to the yeast protein Vma21p which resides in the endoplasmic reticulum and is required for the assembly of the Vo complex. However, as deduced from immunoblots as well as from activities of the V-ATPase and endoplasmic reticulum marker enzymes in different membrane preparations, M9.7 is, in contrast to the yeast polypeptide, a constitutive subunit of the mature plasma membrane V-ATPase of M. sexta.
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Affiliation(s)
- H Merzendorfer
- Department of Biology, University of Osnabrück, D-49069 Osnabrück, Germany
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25
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Winter J, Bilbe G, Richener H, Sehringer B, Kayser H. Cloning of a cDNA encoding a novel cytochrome P450 from the insect Locusta migratoria: CYP6H1, a putative ecdysone 20-hydroxylase. Biochem Biophys Res Commun 1999; 259:305-10. [PMID: 10362503 DOI: 10.1006/bbrc.1999.0783] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The biosynthesis of the steroidal molting hormone, 20-hydroxyecdysone, of arthropods involves a series of cytochrome P450-catalyzed hydroxylations. None of the many sequences of insect cytochromes P450, known to date, is related to ecdysteroid pathways. Here, we report the cloning and sequencing of a full-length cDNA of a new cytochrome P450, classified as CYP6H1, from malpighian tubules of the locust, Locusta migratoria. The 1854 bp DNA contained an open reading frame coding for a protein of 542 amino acids, a 5'-leader sequence and a 3'-untranslated region containing a polyadenylation signal and a poly(A) tail. The encoded protein had been isolated as an ecdysone-binding cytochrome P450 from microsomes of the same tissue in previous work. The closest homolog of CYP6H1 was CYP6A2 from Drosophila with 42.1% identity. According to Northern analysis, CYP6H1 is predominantly expressed at larval instars and in malpighian tubules. Evidence is presented for a functional assignment of CYP6H1 to microsomal ecdysone 20-hydroxylase of the locust.
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Affiliation(s)
- J Winter
- Research Biochemistry, Novartis Crop Protection AG, Basel, CH-4002, Switzerland
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26
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de Azeredo-Oliveira MT, Mello ML. Peroxidase activity in Malpighian tubules of Triatoma infestans Klug. Cytobios 1998; 93:83-92. [PMID: 9734344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Benzidine and diamino benzidine (DAB) oxidation, typically performed by peroxidases, was demonstrated by light and electron microscopy in peroxisomes, mitochondria and membranous structures which occurred in close contact with urate crystals in Malpighian tubules of nymphs and adults of Triatoma infestans. Peroxisomes were predominantly identified in cells of the distal region of the tubules, which is engaged in excretory mechanisms. DAB oxidation in mitochondria, even in the absence of hydrogen peroxide, may indicate the existence of a mitochondrial peroxidase and possibly a cytochrome c peroxidase. The localization of the extracellular membranous structures appeared restricted to the lumen of the proximal region of the tubules and they were assumed to be remnants of endoplasmic reticulum containing peroxidases.
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de Azeredo-Oliveira MT, Mello ML. Acid phosphatase activity in Malpighian tubules of Triatoma infestans Klug. Cytobios 1998; 92:23-8. [PMID: 9682470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Acid phosphatase activity was detected in the Malpighian tubules of the blood-sucking hemipteran, Triatoma infestans. The enzyme activity was especially prominent in the cytoplasmic globules which were assumed to be laminated 'concretions', which occur in the distal cells of the organ. It was also verified in the nuclei and in some cytoplasmic granules (lysosomes) of the proximal cells. The data indicated that lysosomes were involved with the nature or origin of the laminated concretions, but it is still questionable whether acid phosphatase activity exists in the nuclei.
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28
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Logullo C, Vaz IDS, Sorgine MH, Paiva-Silva GO, Faria FS, Zingali RB, De Lima MF, Abreu L, Oliveira EF, Alves EW, Masuda H, Gonzales JC, Masuda A, Oliveira PL. Isolation of an aspartic proteinase precursor from the egg of a hard tick, Boophilus microplus. Parasitology 1998; 116 ( Pt 6):525-32. [PMID: 9651935 DOI: 10.1017/s0031182098002698] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
An aspartic proteinase precursor, herein named BYC (Boophilus Yolk pro-Cathepsin) was isolated from eggs of the hard tick, Boophilus microplus. As judged by electrophoresis on sodium dodecyl sulfate polyacrylamide slab gel (SDS-PAGE), purified BYC presented 2 bands of 54 and 49 kDa, bearing the same NH2-terminal amino acid sequence. By Western blot analysis, BYC was also found in the haemolymph, indicating an extraovarian site of synthesis. Several organs were incubated in culture medium with [35S]methionine, and only the gut and fat body showed synthesis of BYC polypeptides. Protein sequencing of both the NH2-terminal and an internal sequence obtained after cyanogen bromide (CNBr) cleavage of BYC revealed homology with several aspartic proteinase precursors. Incubation at pH 3.5 resulted in autoproteolysis of BYC, which produced the mature form of the enzyme, that displayed pepstatin-sensitive hydrolytic activity against haemoglobin. Western blot analysis using anti-BYC monoclonal antibodies showed proteolytic processing of BYC during embryogenesis and suggested activation of the enzyme during development. A role of BYC in degradation of vitellin, the major yolk protein of tick eggs, is discussed.
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Affiliation(s)
- C Logullo
- Departamento de Bioquímica Médica, ICB-CCS-UFRJ, Cidade Universitária, Rio de Janeiro, RJ, Brazil.
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29
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al-Fifi ZI, Marshall SL, Hyde D, Anstee JH, Bowler K. Characterization of ATPases of apical membrane fractions from Locusta migratoria Malpighian tubules. Insect Biochem Mol Biol 1998; 28:201-211. [PMID: 9684329 DOI: 10.1016/s0965-1748(98)00025-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Apical and basal membrane fractions from Locusta Malpighian tubules were prepared and were characterized by marker enzyme analysis. The apical membranes contained an azide- and orthovanadate-insensitive ATPase activity that was inhibited by bafilomycin A1 (IC50 = 0.44 nM) and NEM (IC50 = 2.15 microM), and thus was characterized as putative V-type ATPase. The enzyme was stimulated by a variety of monovalent cations (Tris > K = Na > choline > Li = Rb) maximal stimulation occurring at 30-40 mM. It was also stimulated by a variety of monovalent anions (maximal activation 30-40 mM), but was strongly inhibited by nitrate and thiocyanate. SDS-PAGE separation of proteins present in the various membrane fractions was carried out. The apical membrane fraction alone contained a 28 kDa protein band that bound a monoclonal antibody specific for a 28 kDa peptide which was a component of the V-type ATPase from midgut of Manduca sexta and, in native gels, possessed ATPase activity which was also sensitive to both bafilomycin and NEM but not to azide or orthovanadate. Binding of the fluorescent monoclonal antibody was located at the apical boundary of the tubule cells. It was concluded that a V-type ATPase is present at the apical surface of Locusta Malpighian tubule cells and that it is involved in their secretory functioning.
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Affiliation(s)
- Z I al-Fifi
- Department of Biological Sciences, King Abdul Aziz University, Jeddah, Saudi Arabia
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Caruso-Neves C, Meyer-Fernandes JR, Saad-Nehme J, Proverbio F, Marín R, Lopes AG. Ouabain-insensitive Na(+)-ATPase activity of Malpighian tubules from Rhodnius prolixus. Comp Biochem Physiol B Biochem Mol Biol 1998; 119:807-11. [PMID: 9787771 DOI: 10.1016/s0305-0491(98)00057-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In the present paper, we show the existence of a furosemide-sensitive Na(+)-stimulated, Mg(2+)-dependent ATPase activity in cell lysates of Malpighian tubular cells from Rhodnius prolixus, which could be the biochemical expression of the Na(+)-pump. The main characteristics of this activity are: (1) K0.5 for Na+ = 1.49 +/- 0.18 mM, (2) Vmax = 2.8 +/- 0.1 nmol inorganic orthophosphate (Pi).mg prot-1.min-1, (3) it is fully abolished by 2 mM furosemide, (4)it is insensitive to ouabain concentrations up to 10(-2) M, (5) it is sensitive to the presence of vanadate in the incubation medium indicating it to be a P-type ATPase, and (6) it is stimulated by nanomolar concentrations of Ca2+ in the incubation medium.
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Affiliation(s)
- C Caruso-Neves
- Instituto de Biofísica Carlos Chagas Filho, UFRJ, Rio de Janeiro, Brazil
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31
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Abstract
Using conserved amino acid sequences for the design of oligonucleotide primers, we isolated cDNA clones for two subunits of the V-ATPase from the midgut and Malpighian tubules of Aedes aegypti larvae. The 3.1 kb cDNA of the A subunit of the peripheral catalytic V1 sector codes for a protein of 68.6 kDa. The protein contains conserved motifs, including an ATP/GTP binding site, found in all other A subunits. Southern analysis using the A subunit as a probe suggests the presence of only a single copy of gene in the Aedes aegypti. The 0.85 kb cDNA of the c subunit of the membrane H+ conducting V0 sector codes for a protein of kDa. This protein has four transmembrane domains and contains a conserved glutamic acid that serves as the binding site for dicyclohexylcarbodiimide. Southern analysis using the c subunit as a probe suggests the presence of more than one related gene in the genome of Aedes aegypti. Pileup analysis of various A and c subunits shows that these subunits fall into distinct clusters, including one in which all arthropod proteins are clustered.
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Affiliation(s)
- S S Gill
- Department of Entomology, University of California, Riverside 92521, USA.
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32
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Davies SA, Stewart EJ, Huesmann GR, Skaer NJ, Maddrell SH, Tublitz NJ, Dow JA. Neuropeptide stimulation of the nitric oxide signaling pathway in Drosophila melanogaster Malpighian tubules. Am J Physiol 1997; 273:R823-7. [PMID: 9277574 DOI: 10.1152/ajpregu.1997.273.2.r823] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Activation of the nitric oxide (NO) and guanosine 3', 5'-cyclic monophosphate (cGMP) signaling pathway stimulates fluid secretion by the Drosophila melanogaster Malpighian tubule. The neuropeptide cardioacceleratory peptide 2b (CAP2b) has been previously shown to stimulate fluid secretion in this epithelium by elevating intracellular cGMP levels. Therefore, it was of interest to investigate if CAP2b acts through NO in isolated tubules and thus presumably through stimulation of a tubule NO synthase (NOS). We show here by reverse-transcription polymerase chain reaction that Drosophila NOS (dNOS) is expressed in Malpighian tubules. Biochemical assays of NOS activity in whole tubules show that CAP2b significantly stimulates NOS activity. Additionally, fluid secretion and cyclic nucleotide assays show that CAP2b-induced elevation of intracellular cGMP levels and fluid secretion rates are dependent on the activation of a soluble guanylate cyclase. Treatment of tubules with a specific NOS inhibitor abolishes the CAP2b-induced rise in intracellular cGMP levels. These data indicate that CAP2b stimulates NOS and therefore, endogenous NO production, which, in turn, stimulates a soluble guanylate cyclase. This is the first demonstration of stimulation of an endogenous NOS by a defined peptide in Drosophila.
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Affiliation(s)
- S A Davies
- Division of Molecular Genetics, University of Glasgow, United Kingdom
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33
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Abstract
V-ATPases are phylogenetically widespread, highly conserved, multisubunit proton pumps. Originally characterised in endomembranes, they have been found to energise transport across plasma membranes in a range of animal cells and particularly in certain epithelia. While yeast is the model of choice for the rapid generation and identification of V-ATPase mutants, it does not allow their analysis in a plasma membrane context. For such purposes, Drosophila melanogaster is a uniquely suitable model. Accordingly, we have cloned and characterised genes encoding several V-ATPase subunits in D. melanogaster and, using P-element technology, we have succeeded in generating multiple new alleles. Reporter gene constructs reveal ubiquitous expression, but at particularly high levels in those epithelial thought to be energised by V-ATPases, and several of the alleles have lethal recessive phenotypes characterised by epithelial dysfunction. These results, while providing the first gene knockouts of V-ATPases in animals, also illustrate the general utility of D. melanogaster as a model for the genetic analysis of ion transport and its control in epithelia.
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Affiliation(s)
- J A Dow
- Division of Molecular Genetics, University of Glasgow, UK.
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Choi SK, Choi HK, Kadono-Okuda K, Taniai K, Kato Y, Yamamoto M, Chowdhury S, Xu J, Miyanoshita A, Debnath NC. Occurrence of novel types of nitric oxide synthase in the silkworm, Bombyx mori. Biochem Biophys Res Commun 1995; 207:452-9. [PMID: 7531973 DOI: 10.1006/bbrc.1995.1209] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Nitric oxide (NO) synthase activity was detected in fat body and the Malpighian tubles of the silkworm, Bombyx mori. Main NO synthase activity in the fat body was Ca(2+)/calmodulin-dependent, inducible by bacterial lipopolysaccharide (LPS) and required NADPH, FAD, FMN, dithiothreitol (DTT) and tetrahydrobiopterin (BH4) as cofactors for the full expression of the activity. The Malpighian tubles contained two types of NO synthase. One was Ca(2+)-independent, calmodulin-dependent and constitutive and the other was Ca(2+)-dependent and constitutive. The former NO synthase required the same cofactors as fat body NO synthase. The activity of Malpighian tuble NO synthases increased dramatically at the end of the last instar period, just prior to spinning. These results indicate that B. mori contains new types of NO synthase, suggesting the wide distribution and different characteristics of this enzyme among vertebrates and invertebrates.
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Affiliation(s)
- S K Choi
- Laboratory of Biological Defense, National Institute of Sericultural and Entomological Science, Ibaraki, Japan
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35
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Zhang SL, Leyssens A, Van Kerkhove E, Weltens R, Van Driessche W, Steels P. Electrophysiological evidence for the presence of an apical H(+)-ATPase in Malpighian tubules of Formica polyctena: intracellular and luminal pH measurements. Pflugers Arch 1994; 426:288-95. [PMID: 8183639 DOI: 10.1007/bf00374784] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Cellular and luminal pH of isolated ant Malpighian tubules were measured in different bath K+ concentrations using double-barrelled pH microelectrodes. The electrochemical gradient for H+ across the basolateral and the apical cell membranes was estimated. In control Ringer (51 mmol/l K+) cell and luminal pH were alkaline with respect to the basolateral solution: 7.77 and 7.36, respectively, versus 7.25. On lowering basolateral K+ concentration to 5 mmol/l or increasing it to 113 mmol/l, luminal pH and to a lesser extent cell pH followed: luminal pH changed to 7.14 and 7.43 and cell pH to 7.69 and 7.82, respectively. In all conditions a cell inward electrochemical gradient for protons across both membranes was observed. Increasing basolateral K+ concentration, which was positively correlated with secretion rate, decreased the cell inwardly directed apical proton gradient; moreover, the apical membrane potential difference decreased as well, from -93 mV in 5 mmol/l K+ to -65 mV in 113 mmol/l K+. Therefore the turnover rate of the electrogenic active proton pump at the apical membrane is facilitated in a high basolateral K+ concentration. The calculated electromotive force of this pump is -159 mV. Comparing the proton with the K+ electrochemical gradient, taken from another study in the same experimental conditions, we find that the apical proton electrochemical gradient can drive K+ extrusion into the lumen for each value of secretion rate.
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Affiliation(s)
- S L Zhang
- Department Medische Basiswetenschappen, Limburgs Universitair Centrum, Diepenbeek, Belgium
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36
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al-Robai AA. Different ouabain sensitivities of Na+/K(+)-ATPase from Poekilocerus bufonius tissues and a possible physiological cost. Comp Biochem Physiol B 1993; 106:805-12. [PMID: 8299345 DOI: 10.1016/0305-0491(93)90034-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
1. The properties of Na+/K(+)-transporting ATPase in microsomal preparation from mid-gut of the grasshopper, Poekilocerus bufonius, were investigated and compared with the same enzyme from brain and excretory system. 2. Two components of ATPases activity are present in the three tissues studied. 3. The physiochemical properties of Na+/K(+)-transporting ATPase from mid-gut, brain and excretory system (hind-gut plus Malpighian tubules) are essentially the same. 4. The calculated values of PI50 were 2 (I50 = 1 x 10(-2) M), 3.7 (I50 = 2 x 10(-4) M) and 6.4 (I50 = 3.98 x 10(-7)) for Na+/K(+)-ATPase from mid-gut, excretory system and brain, respectively. The mid-gut contains the most ouabain-resistant Na+/K(+)-ATPase. 5. The results suggest that P. bufonius have developed some tolerance to toxic cardiac glycosides (CGS), but there is a possibility of autotoxicity as indicated by the presence of ouabain-sensitive ATPase from brain tissue. 6. It was concluded that the dissimilarities of Na+/K(+)-ATPases from different tissues of P. bufonius are probably due to tissue-dependent differences in ouabain sensitivity (or isoenzymes pattern) available in the same insect. 7. The atrophy of female flight muscle of P. bufonius suggests the possibility of physiological cost inflicted on insects consuming poisonous plants.
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Affiliation(s)
- A A al-Robai
- Department of Biology, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
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37
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Pietrantonio PV, Gill SS. Sequence of a 17 kDa vacuolar H(+)-ATPase proteolipid subunit from insect midgut and Malpighian tubules. Insect Biochem Mol Biol 1993; 23:675-680. [PMID: 8353524 DOI: 10.1016/0965-1748(93)90041-p] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A 0.4 kb polymerase chain reaction (PCR) product obtained from cDNA made from the midgut and Malpighian tubules of fifth instar larvae of Heliothis virescens was used to screen a larval midgut and Malpighian tubules cDNA library. Four clones were obtained, one of 1.9 kb and others of 1.4 kb. The 1.9 kb clone encodes a 17.2 kDa protein which is highly homologous to other vacuolar ATPases proteolipids. Putative N-glycosylation and DCCD binding sites were observed at amino acid residues 83 and 139, respectively.
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Affiliation(s)
- P V Pietrantonio
- Department of Entomology, University of California, Riverside 92521
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38
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Abstract
Vacuolar ATPases (V-ATPases), originally characterised as components of endomembranes, have also been implicated in epithelial ion transport, both in vertebrates and in insects. The ATPase is particularly noteworthy in lepidopteran larvae, where it generates large transepithelial potential differences and short-circuit currents across the midgut epithelium. A cDNA library from Manduca sexta larval midguts and Malpighian tubules was screened with a Drosophila melanogaster cDNA encoding the 16-kDa proteolipid subunit of the V-ATPase, and a 1.4-kb cDNA sequenced in its entirety. The sequence contains a long open reading frame, encoding a putative peptide of 156 amino acids (aa) and with an M(r) of 15,967, in close agreement with values previously suggested by sodium dodecyl sulfate-polyacrylamide gels of M. sexta midgut proteins. Correspondence of the deduced aa sequence with those of other species, particularly D. melanogaster, was extremely close. Northern blots of M. sexta midgut mRNA at high stringency revealed two transcripts of 1.4 and 1.9 kb, whereas genomic Southern blots suggest that there is only a single copy of the gene in M. sexta. The possibility that members of the 16-kDa gene family might serve multiple roles in transport and membrane communication is discussed.
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Affiliation(s)
- J A Dow
- Department of Cell Biology, University of Glasgow, UK
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39
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Abstract
Drosophila affinidisjuncta and Drosophila hawaiiensis are closely related species that display distinct tissue-specific expression patterns for their homologous alcohol dehydrogenase genes (Adh genes). In Drosophila melanogaster transformants, both genes are expressed at high levels in the larval and adult fat bodies, but the D. affinidisjuncta gene is expressed 10-50-fold more strongly in the larval and adult midguts and Malpighian tubules. The present study reports the mapping of cis-acting sequences contributing to the regulatory differences between these two genes in transformants. Chimeric genes were constructed and introduced into the germ line of D. melanogaster. Stage- and tissue-specific expression patterns were determined by measuring steady-state RNA levels in larvae and adults. Three portions of the promoter region make distinct contributions to the tissue-specific regulatory differences between the native genes. Sequences immediately upstream of the distal promoter have a strong effect in the adult Malpighian tubules, while sequences between the two promoters are relatively important in the larval Malpighian tubules. A third gene segment, immediately upstream of the proximal promoter, influences levels of the proximal Adh transcript in all tissues and developmental stages examined, and largely accounts for the regulatory difference in the larval and adult midguts. However, these as well as other sequences make smaller contributions to various aspects of the tissue-specific regulatory differences. In addition, some chimeric genes display aberrant RNA levels for the whole organism, suggesting close physical association between sequences involved in tissue-specific regulatory differences and those important for Adh expression in the larval and adult fat bodies.
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Affiliation(s)
- X M Fang
- Biochemistry Department, University of Louisville Medical School, Kentucky 40292
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40
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Russell VE, Klein U, Reuveni M, Spaeth DD, Wolfersberger MG, Harvey WR. Antibodies to mammalian and plant V-ATPases cross react with the V-ATPase of insect cation-transporting plasma membranes. J Exp Biol 1992; 166:131-43. [PMID: 1534830 DOI: 10.1242/jeb.166.1.131] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In immunobiochemical blots, polyclonal antibodies against subunits of plant and mammalian vacuolar-type ATPases (V-ATPases) cross-react strongly with corresponding subunits of larval Manduca sexta midgut plasma membrane V-ATPase. Thus, rabbit antiserum against Kalanchoe daigremontiana tonoplast V-ATPase holoenzyme cross-reacts with the 67, 56, 40, 28 and 20 kDa subunits of midgut V-ATPase separated by SDS-PAGE. Antisera against bovine chromaffin granule 72 and 39 kDa V-ATPase subunits cross-react with the corresponding 67 and 43 kDa subunits of midgut V-ATPase. Antisera against the 57 kDa subunit of both beet root and oat root V-ATPase cross-react strongly with the midgut 56 kDa V-ATPase subunit. In immunocytochemical light micrographs, antiserum against the beet root 57 kDa V-ATPase subunit labels the goblet cell apical membrane of both posterior and anterior midgut in freeze-substituted and fixed sections. The plant antiserum also labels the apical brush-border plasma membrane of Malpighian tubules. The ability of antibodies against plant V-ATPase to label these insect membranes suggests a high sequence homology between V-ATPases from plants and insects. Both of the antibody-labelled insect membranes transport K+ and both membranes possess F1-like particles, portasomes, on their cytoplasmic surfaces. This immunolabelling by xenic V-ATPase antisera of two insect cation-transporting membranes suggests that the portasomes on these membranes may be V-ATPase particles, similar to those reported on V-ATPase-containing vacuolar membranes from various sources.
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Affiliation(s)
- V E Russell
- Department of Entomology, Purdue University, West Lafayette, IN 47907
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41
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Abstract
The pattern of cell activities resulting in the generation of a simple tubular epithelium, the Malpighian tubules of Rhodnius prolixus, is examined during embryogenesis. The anlage of the tubules is shown to be of ectodermal origin. An evolving pattern of cycling cells in the primordia is revealed using the immunocytochemical localization of a substituted nucleotide, BUdR. A cell unique to each tubule is shown not to enter the cell cycle but to be required for the proliferation of the remaining cells in the tubules. Furthermore, the activity of this cell imposes on each tubule a clear proximo-distal axis.
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Affiliation(s)
- H Skaer
- Department of Zoology, University of Cambridge, United Kingdom
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42
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Gill SS, Ross LS. Molecular cloning and characterization of the B subunit of a vacuolar H(+)-ATPase from the midgut and Malpighian tubules of Helicoverpa virescens. Arch Biochem Biophys 1991; 291:92-9. [PMID: 1834020 DOI: 10.1016/0003-9861(91)90109-v] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Using the polymerase chain reaction (PCR) a 0.8-kb product was amplified from cDNA made from the midgut and Malpighian tubules of fifth instar larvae of Helicoverpa virescens. This 0.8-kb PCR product was then used to isolate a clone of the B subunit of the V-type ATPase from a cDNA library made from the same tissues. The cDNA clone encodes for a protein of 55 kDa which shows very high amino acid homology to other known B subunits of V-type ATPases. The transcript size of the B subunit in the midgut of H. virescens was 2.3 kb, and a transcript of identical size was also detected in the Malpighian tubules. Northern blot analysis revealed the presence of a homologous transcript of 2.6 kb in the midgut of Manduca sexta and PCR analysis also confirmed the presence of such a transcript in the Malpighian tubules and the nervous system of M. sexta, and in the midgut Malpighian tubules of Culex quinquefasciatus. The presence of the V-type ATPase in the Malpighian tubules of lepidopteran insects suggests that the transport of ions across the cell membrane in this tissue is also probably driven by a similar process as that observed in the midgut of these insects.
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Affiliation(s)
- S S Gill
- Department of Entomology, University of California, Riverside 92521
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Reveillaud I, Niedzwiecki A, Bensch KG, Fleming JE. Expression of bovine superoxide dismutase in Drosophila melanogaster augments resistance of oxidative stress. Mol Cell Biol 1991; 11:632-40. [PMID: 1899285 PMCID: PMC359714 DOI: 10.1128/mcb.11.2.632-640.1991] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Superoxide dismutases (SOD) play a major role in the intracellular defense against oxygen radical damage to aerobic cells. In eucaryotes, the cytoplasmic form of the enzyme is a 32-kDa dimer containing two copper and two zinc atoms (CuZn SOD) that catalyzes the dismutation of the superoxide anion (O2-) to H2O2 and O2. Superoxide-mediated damage has been implicated in a number of biological processes, including aging and cancer; however, it is not certain whether endogenously elevated levels of SOD will reduce the pathological events resulting from such damage. To understand the in vivo relationship between an efficient dismutation of O2- and oxidative injury to biological structures, we generated transgenic strains of Drosophila melanogaster overproducing CuZn SOD. This was achieved by microinjecting Drosophila embryos with P-elements containing bovine CuZn SOD cDNA under the control of the Drosophila actin 5c gene promoter. Adult flies of the resulting transformed lines which expressed both mammalian and Drosophila CuZn SOD were then used as a novel model for evaluating the role of oxygen radicals in aging. Our data show that expression of enzymatically active bovine SOD in Drosophila flies confers resistance to paraquat, an O2(-)-generating compound. This is consistent with data on adult mortality, because there was a slight but significant increase in the mean lifespan of several of the transgenic lines. The highest level of expression of the active enzyme in adults was 1.60 times the normal value. Higher levels may have led to the formation of toxic levels of H2O2 during development, since flies that died during the process of eclosion showed an unusual accumulation of lipofuscin (age pigment) in some of their cells. In conclusion, our data show that free-radical detoxification has a minor by positive effect on mean longevity for several strains.
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Affiliation(s)
- I Reveillaud
- Sasakawa Center for Aging Research, Linus Pauling Institute of Science and Medicine, Palo Alto, California 94306
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44
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Abstract
(S)-9-(2,3-dihydroxypropyl) adenine (DHPA), D-eritadenine and some other open-chain nucleoside analogues, which exhibit adverse biological effects in microorganisms, plants and animals, cause pronounced inhibition of intestinal phosphatases in the hemipteran insect Pyrrhocoris apterus. The rate of p-nitrophenylphosphate hydrolysis by homogenates from intestinal epithelium and Malpighian tubules was inhibited up to 94% by 2-10 millimolar concentrations of these drugs. This effect is stronger than that of sodium fluoride, which is recognized as a common inhibitor of phosphatase. We conclude that inhibition of phosphatase activity in the digestive and excretory organs may be responsible for the previously reported massive excretion of phosphorylated derivatives of the nucleoside analogues after their oral administration to insects.
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Affiliation(s)
- V Nĕmec
- Institute of Entomology, Czechoslovak Academy of Sciences, Ceské, Budĕjovice
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45
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Brennan MD, Wu CY, Berry AJ. Tissue-specific regulatory differences for the alcohol dehydrogenase genes of Hawaiian Drosophila are conserved in Drosophila melanogaster transformants. Proc Natl Acad Sci U S A 1988; 85:6866-9. [PMID: 3137574 PMCID: PMC282079 DOI: 10.1073/pnas.85.18.6866] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Naturally occurring regulatory variation is a source of genetic variability that is well documented but poorly understood. Two members of the Hawaiian picture-winged Drosophila, D. affinidisjuncta and D. hawaiiensis, display markedly different levels of alcohol dehydrogenase (alcohol: NAD+ oxidoreductase, EC 1.1.1.1) in the larval midgut and Malpighian tubules. To analyze the regulation of the alcohol dehydrogenase genes from these two species, their homologous alcohol dehydrogenase genes were cloned and introduced, via P element-mediated transformation, into the germ line of Drosophila melanogaster. Histochemical and electrophoretic analyses of larval transformants demonstrate that major differences in the tissue-specific levels of alcohol dehydrogenase production are characteristic of the alcohol dehydrogenase genes themselves. While these results do not directly address possible species-specific differences in the tissue distribution of trans-acting regulatory components, they indicate that demonstrable differences in cis-dominant regulatory information are sufficient to account for the observed regulatory variation.
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Affiliation(s)
- M D Brennan
- Department of Biology, University of Alabama, Tuscaloos 35486
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46
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Abstract
Drosophila alcohol dehydrogenase (Adh) genes are expressed in the fat body and in species-specific sets of other tissues during larval and adult development. The Drosophila mulleri Adh-1 gene is expressed in the larval fat body and in three other larval tissues. In this paper, we show that Adh-1 expression in multiple cell types is the result of synergistic interactions between fat body-specific enhancers and a specific Adh-1 promoter element.
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Affiliation(s)
- J A Fischer
- Department of Biochemistry and Molecular Biology, Harvard University, Cambridge, Massachusetts 02138
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47
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Abstract
A cDNA library from third-instar larval Malpighian tubules of Drosophila melanogaster was constructed and screened for urate oxidase (UO) clones by hybridization selection. The coding sequence for UO was mapped by in situ hybridization to position 28C on the left arm of chromosome 2. The UO activity in Drosophila shows a complex developmental profile. A UO cDNA was used as a probe of Northern blots of poly(A) + RNA from various stages of development. The data show that there is a direct correlation between the transcriptional activity of the UO locus as evidenced by the quantitative changes of UO mRNA and the levels of UO activity and protein during development.
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48
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Clark SH, Daniels S, Rushlow CA, Hilliker AJ, Chovnick A. Tissue-specific and pretranslational character of variants of the rosy locus control element in Drosophila melanogaster. Genetics 1984; 108:953-68. [PMID: 6150879 PMCID: PMC1224276 DOI: 10.1093/genetics/108.4.953] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Prior reports from this laboratory have described the experimental basis for our understanding of the genetic organization of the rosy locus (ry:3-52.0) of Drosophila melanogaster, as a bipartite genetic entity consisting of a structural element that codes for the xanthine dehydrogenase (XDH) peptide and a contiguous, cis-acting control element. The present report describes our progress in the analysis of the control element and its variants. Characterization of the control element variants reveals that, with respect to late third instar larval tissue distribution of XDH activity and cross-reacting material, i409H is associated with a large, tissue-specific increase in fat body which is not observed in malpighian tubules. Further data are presented in support of the inference that this differential expression must reflect differential production of XDH-specific RNA transcripts.--Gel blot analyses are described which demonstrate that the phenotypic effects associated with variation in the rosy locus control element relate to differences in accumulation of XDH-specific poly-A+ RNA and do not relate to differences in rosy DNA template numbers.--Experiments are described that provide for unambiguous mapping of control element sites through the use of half-tetrad recombination experiments and the recovery and phenotypic characterization of the reciprocal products of exchange between control element site variants. Thus, we are able to order the sites as follows: kar-i1005 i409-ry.
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Abstract
The enzyme catalysing the hydroxylation of ecdysone to 20-hydroxyecdysone, ecdysone 20-mono-oxygenase (EC 1.14.99.22), was investigated in the Malpighian tubules of fifth-instar locusts, Schistocerca gregaria. Enzyme activity was optimal at 35 degrees C and pH 6.8-8.0. Under these conditions the mono-oxygenase exhibited an apparent Km for ecdysone of 7.1 X 10(-7) M, a maximal specific activity of 1.1 nmol/h per mg of protein and was competitively inhibited by 20-hydroxyecdysone with an apparent Ki of 6.3 X 10(-7) M. Enzyme activity was decreased in the presence of Ca2+, Mg2+, EDTA and non-ionic detergents. The Malpighian tubule ecdysone 20-mono-oxygenase was localized primarily in the subcellular fraction sedimenting at 7500 g and, on the basis of marker enzyme profiles, was assigned mainly to the mitochondria. NADPH was required for activity, although addition of NADH together with NADPH had a synergistic effect. NADP+-dependent isocitrate dehydrogenase (EC 1.1.1.42) and an energy-dependent NAD(P) transhydrogenase (EC 1.6.1.1.) appeared to be the major sources of reducing equivalents, with the contribution from the 'malic enzyme' (EC 1.1.1.40) being less important. The monooxygenase was characterized as a cytochrome P-450-containing mixed-function oxidase from the inhibition patterns with metyrapone, CO and cyanide; CO inhibition was reversible with monochromatic light at 450 nm. However, the ecdysone 20-mono-oxygenase shows much lower sensitivity to CO inhibition and to photodissociation of the CO-inhibited complex than do vertebrate cytochrome P-450-dependent hydroxylation systems. The concentration of cytochrome P-450 in the Malpighian tubule mitochondria was 30 pmol/mg of protein. The properties of the mono-oxygenase are discussed in relation to hydroxylation enzymes from other sources.
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Fathpour H, Anstee JH. Effects of various inhibitors and 2,4-dinitrophenol on adenosine triphosphatase from Malpighian tubules of Locusta migratoria L. Experientia 1981; 37:117-9. [PMID: 6453722 DOI: 10.1007/bf01963179] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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