Mechanisms of Acid-Base Transport and Control in Locust Excretory System

Phillips, J. E.; Thomson, Robert K.; Audsley, Neil; Peach, J. L.; Stagg, Andrew P.

doi:10.1086/physzool.67.1.30163837

Cited by 30 publications

(7 citation statements)

References 36 publications

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“…In the desert locust (Schistocerca gregaria), regulation of blood volume and its composition depend on selective reabsorption in the hindgut (ileal and rectal segments) from a primary urine secreted by the Malpighian tubules (reviewed by Phillips et al, 1986Phillips et al, , 1988Phillips et al, , 1994. Stimulation of ileal ion and water reabsorption by ion transport peptide (ScgITP*) has been reported by Audsley et al, (1992a,b).…”

Section: Introductionmentioning

confidence: 99%

Occurrence of ion transport peptide (ITP) and ion transport-like peptide (ITP-L) in orthopteroids

Macins

Meredith

Zhao

et al. 1999

Arch. Insect Biochem. Physiol.

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Comparison of the sequence and biological activity of ITP‐related proteins from other insects on Schistocerca hindgut will provide further understanding of ITP interaction with its receptor (ITPR) and may thus open new avenues of insect pest control if good ITPR antagonists can be developed. Using a specific bioassay (measurement of ileal Cl– transport) and Western blot analysis with antibodies raised to Schistocerca ion transport peptide (ScgITP) sequences, we demonstrate stimulatory ITP‐related peptides in the corpora cardiaca (CC) of several othopteran insects (Schistocerca gregaria, Locusta migratoria, Melanoplus sanguinipes, Xanthippus corallipes, Carausius morosus, Periplaneta americana and Acheta domesticus.). For the first time, we have immunologically detected ITP in Schistocerca brain, the tissue in which ITP transcripts are found and which has some activity in the bioassay. Neither reciprocal bioassays nor immunological results reveal any differences between two locust species, Locusta and Schistocerca, which is consistent with cDNA analysis. Using Schistocerca‐derived primers and the polymerase chain reaction (PCR), we show that Locusta brain contains RNA encoding for peptides with identical sequence to ScgITP and with only a single neutral amino acid change from Schistocerca ion transport‐like peptide (ScgITP‐L). We present evidence that ITP‐L transcripts are present in at least 3 locust/grasshopper genera but have been unable to detect ITP‐L peptide to date in any tissues assayed by Western blotting at a detection limit of 0.8 pmol/tissue. Results indicate high conservation of ITP structure and biological activity among these orthopteroids, in contrast to several other insect orders. Arch. Insect Biochem. Physiol. 40:107–118, 1999. © 1999 Wiley‐Liss, Inc.

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Section: Introductionmentioning

confidence: 99%

Occurrence of ion transport peptide (ITP) and ion transport-like peptide (ITP-L) in orthopteroids

Macins

Meredith

Zhao

et al. 1999

Arch. Insect Biochem. Physiol.

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“…In the locust, an acid load injected into the hemocoel was cleared primarily by the hindgut. The Malpighian tubules secreted acidic fluid, but their contributions to acid-base homeostasis were minor (Harrison et al, 1992;Stagg et al, 1991;Phillips et al, 1993;Harrison, 2001). Responses of locusts to alkaline challenges have not been described.…”

Section: Introductionmentioning

confidence: 99%

Strategies for regulation of hemolymph pH in acidic and alkaline water by the larval mosquitoAedes aegypti(L.) (Diptera; Culicidae)

Clark

Vieira

Huegel

et al. 2007

Journal of Experimental Biology

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SUMMARY The responses of larval Aedes aegypti to media of pH 4, 7 and 11 provide evidence for pH regulatory strategies. Drinking rates in pH 4 media were elevated 3- to 5-fold above those observed in pH 7 or 11. Total body water was elevated during acute exposure to acidic media. During chronic exposure, total body water was decreased and Malpighian tubule mitochondrial luminosity, quantified using Mitotracker Green FM, increased. Malpighian tubule secretion rates and energy demands thus appear to increase dramatically during acid exposure. In alkaline media, drinking rates were quite low. Larvae in pH 11 media excreted net acid (0.12 nequiv H+g–1 h–1) and the pH indicators azolitmin and bromothymol blue revealed that the rectal lumen is acidic in vivo at all ambient pH values. The anal papillae (AP) were found to be highly permeant to acid–base equivalents. Ambient pH influenced the length, and the mass-specific length, of the AP in the presence of NaCl (59.9 mmol l–1). In contrast, the length and mass-specific length of AP were not influenced by ambient pH in low NaCl conditions. Mitochondrial luminosity was reduced in AP of larvae reared in acidic media, and was not elevated in alkaline media, relative to that of larvae reared in neutral media. These data suggest that the AP may compromise acid–base balance in acidic media, and may also be an important site of trade-offs between H+ homeostasis and NaCl uptake in dilute, acidic media.

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“…In locust ileal bioassays, ITP stimulates the uptake of Cl -, K + , Na + , and fluid reabsorption and consequently is an antidiuretic factor. In addition, ITP inhibits active H + secretion (Audsley et al, 1992b;Liao et al, 1996;Phillips et al, 1994). Amino acid sequencing (Audsley et al, 1992a) and cDNA cloning suggest that ITP is derived from a 130 amino acid preproprotein by cleavage on the carboxy (C)-terminal side of amino acids 54 and 55, a putative dibasic cleavage site.…”

Section: Introductionmentioning

confidence: 99%

Analysis of an insect neuropeptide,Schistocerca gregaria ion transport peptide (ITP), expressed in insect cell systems

Pfeifer

Hegedus

Wang

et al. 1999

Arch. Insect Biochem.

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We have produced an active form of Schistocerca gregaria ion transport peptide (ITP) in an insect cell expression system. Transformed Drosophila Kc1 cells secreted a form of ITP into the cell culture medium that was proteolytically cleaved correctly at the amino (N)‐terminus. Concentrated culture supernatant from transformed Kc1 and Hi5 cells had high biological activity when tested on isolated locust ilea. Conversely, ITP expressed by baculovirus‐infected Sf9 cells was larger in size and had decreased specific activity compared to ITP produced by Kc1 cells due to incorrect cleavage of the peptide at the N‐terminus in the baculovirus system. This demonstrates how processing of the secreted foreign protein (ITP) expressed under the late polyhedrin promoter is compromised in a baculovirus‐infected cell. Transient transformation of Kc1 cells results in supernatants containing two forms of ITP; one form (A) co‐elutes with synthetic ITP and the other form (B) has reduced electrophoretic mobility. In contrast, in stably transformed Kc1 cell supernatant, ITP is expressed in a single form, which has the same electrophoretic mobility and specific biological activity as form A produced by transiently transformed Kc1 cells. Arch. Insect Biochem. Physiol. 42:245–252, 1999. © 1999 Wiley‐Liss, Inc.

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Mechanisms of Acid-Base Transport and Control in Locust Excretory System

Cited by 30 publications

References 36 publications

Occurrence of ion transport peptide (ITP) and ion transport-like peptide (ITP-L) in orthopteroids

Occurrence of ion transport peptide (ITP) and ion transport-like peptide (ITP-L) in orthopteroids

Strategies for regulation of hemolymph pH in acidic and alkaline water by the larval mosquitoAedes aegypti(L.) (Diptera; Culicidae)

Analysis of an insect neuropeptide,Schistocerca gregaria ion transport peptide (ITP), expressed in insect cell systems

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