scholarly journals Cold tolerance ofDrosophilaspecies is tightly linked to the epithelial K+transport capacity of the Malpighian tubules and rectal pads

2017 ◽  
Vol 220 (22) ◽  
pp. 4261-4269 ◽  
Author(s):  
Mads Kuhlmann Andersen ◽  
Heath A. MacMillan ◽  
Andrew Donini ◽  
Johannes Overgaard
Keyword(s):  
Cold Tolerance ◽  
Malpighian Tubules ◽  
Transport Capacity ◽  
K Transport

Anti-diuretic activity of a CAPA neuropeptide can compromise Drosophila chill tolerance

2018 ◽  
Author(s):  
Heath A. MacMillan ◽  
Basma Nazal ◽  
Sahr Wali ◽  
Gil Y. Yerushalmi ◽  
Lidiya Misyura ◽  
...  
Keyword(s):  
Ion Transport ◽  
Cold Tolerance ◽  
Malpighian Tubule ◽  
Malpighian Tubules ◽  
Low Doses ◽  
Ion Balance ◽  
The Central Nervous System ◽  
Summary Statement ◽  
Cell Depolarization ◽  
High Doses

AbstractFor insects, chilling injuries that occur in the absence of freezing are often related to a systemic loss of ion and water balance that leads to extracellular hyperkalemia, cell depolarization, and the triggering of apoptotic signalling cascades. The ability of insect ionoregulatory organs (e.g. the Malpighian tubules) to maintain ion balance in the cold has been linked to improved chill tolerance, and many neuroendocrine factors are known to influence ion transport rates of these organs. Injection of micromolar doses of CAPA (an insect neuropeptide) have been previously demonstrated to improve Drosophila cold tolerance, but the mechanisms through which it impacts chill tolerance are unclear, and low doses of CAPA have been demonstrated to cause anti-diuresis in other insects, including dipterans. Here, we provide evidence that low (fM) and high (µM) doses of CAPA impair and improve chill tolerance, respectively, via two different effects on Malpighian tubule ion and water transport. While low doses of CAPA are anti-diuretic, reduce tubule K+ clearance rates and reduce chill tolerance, high doses facilitate K+ clearance from the haemolymph and increase chill tolerance. By quantifying CAPA peptide levels in the central nervous system, we estimated the maximum achievable hormonal titres of CAPA, and found evidence to suggest that CAPA may function as an anti-diuretic peptide in Drosophila. We provide the first evidence of a neuropeptide that can negatively affect cold tolerance in an insect, and the first evidence of CAPA as an anti-diuretic peptide in this ubiquitous insect model.Summary StatementMany insects ion balance in the cold. We show how one neuropeptide can slow ion transport and reduce the cold tolerance of a fly.

Intrinsic regulation of K+ transport in Malpighian tubules (Formica): Electrophysiological evidence

1992 ◽  
Vol 38 (6) ◽  
pp. 431-446 ◽  
Author(s):  
A. Leyssens ◽  
P. Steels ◽  
E. Lohrmann ◽  
R. Weltens ◽  
E. Van Kerkhove
Keyword(s):  
Malpighian Tubules ◽  
Electrophysiological Evidence ◽  
Intrinsic Regulation ◽  
K Transport

Analysis of epithelial K+ transport in Malpighian tubules ofDrosophila melanogaster: evidence for spatial and temporal heterogeneity

2001 ◽  
Vol 204 (13) ◽  
pp. 2289-2299 ◽  
Author(s):  
Mark R. Rheault ◽  
Michael J. O’Donnell
Keyword(s):  
Drosophila Melanogaster ◽  
Distal Segment ◽  
Malpighian Tubules ◽  
Unstirred Layer ◽  
Temporal Heterogeneity ◽  
Lower Segment ◽  
Spatial And Temporal Heterogeneity ◽  
Microelectrode Measurements ◽  
K Transport ◽  
Periodic Reduction

SUMMARYTransport of K+ by the lower, main and distal segments of the Malpighian tubules of Drosophila melanogaster was analyzed using self-referencing K+-selective microelectrodes. Transport properties of the Malpighian tubules of Drosophila melanogaster change along their length. Self-referencing ion-selective (SeRIS) microelectrode measurements (relative to the bath concentration of 20 mmoll−1) showed a 1% reduction (P<0.05) of [K+] in the unstirred layer adjacent to the main segment of the Malpighian tubules, confirming secretion of K+ from the bath to the tubule lumen. Conversely, SeRIS measurements showed a 0.7% increase (P<0.05) in [K+] in the unstirred layer adjacent to the lower segment of Malpighian tubules, confirming reabsorption of K+ from the luminal fluid to the bath. Measurements using SeRIS also showed that the distal segment neither secreted nor reabsorbed K+. There was pronounced spatial heterogeneity in K+ transport by the lower segment and the main segment; not all morphologically similar cells participated equally in K+ transport, nor did all main segment cells respond equally to stimulation of K+ transport by cyclic AMP. Pronounced temporal heterogeneity in K+ reabsorption by the lower Malpighian tubules was also observed. We suggest that this reflects periodic reduction in K+ reabsorption due to retention of fluid within the lower segment when the ureter contracts.

scholarly journals Freeze tolerance of Cyphoderris monstrosa (Orthoptera: Prophalangopsidae)

2016 ◽  
Vol 148 (6) ◽  
pp. 668-672 ◽  
Author(s):  
Jantina Toxopeus ◽  
Jacqueline E. Lebenzon ◽  
Alexander H McKinnon ◽  
Brent J. Sinclair
Keyword(s):  
Cold Tolerance ◽  
Freeze Tolerance ◽  
Malpighian Tubules ◽  
Ice Formation ◽  
Freezing And Thawing ◽  
Tolerance Strategy ◽  
Late Instar ◽  
Freeze Tolerant ◽  
Overwintering Survival

AbstractThe great grig, Cyphoderris monstrosa Uhler (Orthoptera: Prophalangopsidae), is a large (20–30 mm, >1 g), nocturnal ensiferan that inhabits montane coniferous forests in northwestern North America. Cyphoderris monstrosa overwinters as a late instar nymphs, but its cold tolerance strategy has not previously been reported. We collected nymphs from near Kamloops, British Columbia, Canada in late spring to determine their cold tolerance strategy. Cyphoderris monstrosa nymphs were active at low temperatures until they froze at −4.6±0.3 °C. The nymphs survived internal ice formation (i.e., are freeze tolerant), had a lethal temperature between −9 °C and −12 °C, and could survive for between five and 10 days at −6 °C. Isolated C. monstrosa gut, Malpighian tubules, and metafemur muscle tissues froze at temperatures similar to whole nymphs, and likely inoculate freezing in vivo. Hemolymph osmolality was 358±51 mOsm, with trehalose and proline comprising ~10% of that total. Glycerol was not detectable in hemolymph from field-fresh nymphs, but accumulated after freezing and thawing. The control of ice formation and presence of hemolymph cryoprotectants may contribute to C. monstrosa freeze tolerance and overwintering survival.

scholarly journals THE INSECT V-ATPase, A PLASMA MEMBRANE PROTON PUMP ENERGIZING SECONDARY ACTIVE TRANSPORT: IMMUNOLOGICAL EVIDENCE FOR THE OCCURRENCE OF A V-ATPase IN INSECT ION-TRANSPORTING EPITHELIA.

1992 ◽  
Vol 172 (1) ◽  
pp. 345-354 ◽  
Author(s):  
U Klein
Keyword(s):  
Plasma Membrane ◽  
Active Transport ◽  
Proton Pump ◽  
Plasma Membranes ◽  
Polyclonal Antibodies ◽  
Immune Serum ◽  
Malpighian Tubules ◽  
Secondary Active Transport ◽  
Plasma Membrane Proton Pump ◽  
K Transport

Active electrogenic K+ transport in insects serves as the energy source for secretion or absorption in gastrointestinal epithelia or for the receptor current in sensory epithelia. In the larval midgut of the tobacco hornworm Manduca sexta, a vacuolar-type proton pump (V-ATPase) and a K+/nH+ antiport represent the functional elements of the potassium pump. Several immunological findings support the hypothesis that active K+ transport in other insect epithelia may also be energized by a V-ATPase. In immunoblots, crude homogenates of sensilla-rich antennae and Malpighian tubules of M. sexta cross reacted with an immune serum directed to the purified plasma membrane V-ATPase from the midgut; the M. sexta midgut V-ATPase cross reacted with polyclonal antibodies to endomembrane V-ATPases from xenic origin. In immunocytochemical investigations of larvae of M. sexta and adults of Antheraea pernyi, monoclonal antibodies to defined subunits of the purified midgut V-ATPase or polyclonal antibodies to xenic endomembrane V-ATPase labelled the sites of active K+ transport: the goblet cell apical membrane in the midgut, the brush border of Malpighian tubules and the apical projections of the auxiliary cells in antennal sensilla. The functional mechanism of a primary H+-pumping V-ATPase and a secondary H+-dependent K+ transport postulated for K+-transporting insect epithelia may be further applicable to active Na+ or Cl- transport and would provide a unifying concept for all ouabain-insensitive electrogenic ion transport in insects. The findings from the midgut investigations, however, are the first instance in which a V-ATPase provides an alternative to the Na+/K+-ATPase in energizing secondary active transport in animal plasma membranes.

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