Presence and activity of a Dippu-DH31-like peptide in the blood-feeding bug, Rhodnius prolixus

SUMMARYProbing of a host and ingestion of a blood-meal in a fifth instar Rhodnius prolixus results in a cascade of tightly integrated events. The huge blood-meal is pumped into the anterior midgut during feeding, then modified by diuresis and stored until it is digested. While serotonin is known to be a diuretic hormone in R. prolixus, a peptidergic factor(s) was also known to play a role in diuresis. In the present study we employed molecular techniques and mass spectrometry to determine the sequence of a native CRF-like peptide from R. prolixus (Rhopr DH). In addition, we confirmed the distribution and localization of Rhopr DH using in situ hybridization and immunohistochemistry, and demonstrated its potent biological activity on both the anterior midgut and Malpighian tubules.

Section: Distribution Of the Rhopr Dhmentioning

confidence: 86%

Identification of the elusive peptidergic diuretic hormone in the blood-feeding bugRhodnius prolixus: a CRF-related peptide

Brugge

Paluzzi

Schooley

et al. 2011

“…Previous reports showed a significant increase in the rate of fluid secretion when the peptide (referred to then as Dippu-DH 31 ) was applied alone; however, the maximal rates achieved were only ~1.5% of those obtained with a high concentration of 5HT, and the actions of the peptide were highly variable (Te Brugge et al, 2005). Given the small lumen-positive change in TEP in response to RhoprDH 31 , the peptide may stimulate the V-type H + -ATPase on the apical membrane (i.e.…”

Section: Discussionmentioning

confidence: 96%

“…The kinin-related DHs generally act through an increase in intracellular Ca 2+ levels to activate Cl -conductance pathways (O'Donnell et al, 1998;Beyenbach, 2003). The presence and release into the hemolymph of CRF-related, CT-related and kinin-related peptides in R. prolixus have been suggested on the basis of immunohistochemical, radioimmunological and high performance liquid chromatographic techniques (Te Brugge et al, 1999;Te Brugge et al, 2005). The exogenous CRF-related peptides ZooneDH and DippuDH 46 from Zootermopsis nevadensis and Diploptera punctata, respectively, stimulate fluid secretion and increase the cyclic AMP content of the upper tubules of R. prolixus .…”

Section: Introductionmentioning

confidence: 99%

“…The CRF-related peptides are potent stimulators of fluid secretion, capable of eliciting maximal rates of secretion comparable to those of 5HT-stimulated tubules . In contrast, the CT-related peptide DippuDH 31 produces only small increases in secretion rates of R. prolixus upper tubules, equivalent to ~1.5% of maximal rates achieved with 5HT (Te Brugge et al, 2005). Interestingly, the CT-related peptide of R. prolixus has an identical sequence to that of DippuDH 31 and is herein referred to as RhoprDH 31 (Te Brugge et al, in press).…”

Section: Introductionmentioning

confidence: 99%

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Differential actions of diuretic factors on the Malpighian tubules ofRhodnius prolixus

Donini

O’Donnell

Orchard

2008

+]. Upper tubules responded to ZooneDH with a characteristic triphasic change in the transepithelial potential (TEP), reminiscent of the response to 5-hydroxytryptamine (5HT). RhoprDH 31 produced a small (~9·mV) lumen-positive shift in TEP of the upper tubule but had no effect on the rate of fluid secretion or ion composition of the secreted fluid. In contrast to 5HT, both peptides failed to activate KCl reabsorption by the lower tubule. Leucokinin I had no effect on the ion composition of fluid secreted by whole or upper Malpighian tubules. We propose that: (1) 5HT and a native CRF-related peptide similar to ZooneDH activate the same second messenger systems and ion transporters in the upper tubule cells; (2) CRF-related peptide is utilized to maintain high rates of fluid secretion during the post-feeding diuresis and is additionally used at times when KCl reabsorption is unnecessary or detrimental. The differential actions of multiple diuretic factors allows for intricate control of ionic and osmotic balance in R. prolixus.

“…This process involves the coordinated activity of the crop, Malpighian tubules (MTs) and HG, regulated by neurosecretory mechanisms, including diuretic signals such as serotonin (Maddrell et al, 1991, Orchard, 2006. The presence of diuretic and anti-diuretic peptides acting together with serotonin has been also documented in the bug Rhodnius prolixus (Orchard, 2006;Paluzzi and Orchard, 2006;Quinlan et al, 1997;Te Brugge et al, 1999;Te Brugge et al, 2001;Te Brugge and Orchard, 2002;Te Brugge et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Allatotropin-like peptide released by Malpighian tubules induces hindgut activity associated with diuresis in the Chagas disease vector Triatoma infestans (Klug)

Santini

Ronderos

2007

SUMMARY Haematophagous insects incorporate a large amount of blood with each meal,producing a big quantity of urine in a few hours to eliminate the excess water and Na+. Malpighian tubules (MTs) have traditionally been seen as a system that responds to neuroendocrine stimulus. In a related paper, we demonstrated that MTs of Triatoma infestans produce an autonomous endocrine secretion of an allatotropin-like (AT-like) peptide. In the present study, we report a myostimulatory activity of AT at the level of the hindgut(HG), associated with endocrine mechanisms regulating post-prandial diuresis. Allatotropin induced an increase in frequency and intensity of peristaltic contractions at the level of the HG. The release of the HG content in MTs–HG in vitro preparations undergoing an osmotic shock occurred at different times, depending on the number of MTs present, and there was no release in treatments without MTs. The application of an AT-antiserum to MTs–HG preparations undergoing osmotic shock produced a delay or a long-term blockade of diuresis, depending on the antiserum dilution applied. Similar results were obtained when AT-antiserum was applied in vivoprior to blood intake, decreasing the volume of urine eliminated during the first 2 h. Our results allow us to assign a specific endocrine function to the AT-like peptide released by MTs that is linked to the elimination of urine after blood meals.