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

Probing 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.

Identification of kinin-related peptides in the disease vector, Rhodnius prolixus.

We have used an in silico approach to identify a gene from the blood-gorging vector, Rhodnius prolixus, that is predicted to produce an insect kinin prepropeptide. The prepropeptide is 398 amino acids in length and can potentially produce a large number of kinin-related peptides following post-translational processing. A comparison with other insect kinin precursor sequences demonstrates greatest conservation at the C-terminal region of the kinin peptides.

The antidiuretic neurohormone RhoprCAPA-2 downregulates fluid transport across the anterior midgut in the blood-feeding insect Rhodnius prolixus.

Osmotic balance in insects is regulated by the excretory system, consisting of Malpighian tubules and the gut under the control of diuretic and antidiuretic factors. Terrestrial insects must conserve water, and antidiuresis is the norm, only interrupted by brief diuretic periods. Surprisingly, little is known about antidiuresis in insects.

Neurohormones implicated in the control of Malpighian tubule secretion in plant sucking heteropterans: The stink bugs Acrosternum hilare and Nezara viridula.

Plant sucking heteropteran bugs feed regularly on small amounts of K(+)-rich plant material, in contrast to their hematophagous relatives which imbibe large volumes of Na(+)-rich blood. It was anticipated that this would be reflected in the endocrine control of Malpighian tubule (MT) secretion. To explore this, neuroendocrine factors known to influence MT secretion were tested on MT of the pentatomid plant sucking stink bugs, Acrosternum hilare and Nezara viridula, and the results compared with previously published data from Rhodnius prolixus.

Molecular characterization of neuropeptide F from the eastern subterranean termite Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae).

Neuropeptide F (NPF)-like immunoreactivity was previously found to be abundant in the eastern subterranean termite, Reticulitermes flavipes. Purification of the NPF from a whole body extract of worker termites was accomplished in the current study by HPLC and heterologous radioimmunoassay for an NPF-related peptide, Helicoverpa zea Midgut Peptide-I. A partial amino acid sequence allowed determination of the corresponding cDNA that encoded an open reading frame deduced for authentic R.

Biological activity of diuretic factors on the anterior midgut of the blood-feeding bug, Rhodnius prolixus.

Probing of a host and ingestion of a blood-meal in a fifth instar Rhodnius prolixus results in a cascade of tightly integrated events, including salivary gland secretion, plasticization of the abdominal cuticle, increased ion and water movement across the anterior midgut (crop) and Malpighian tubules (which rapidly produce urine) and the regular expulsion of urine from the hindgut. In this study we have focussed on the role of the anterior midgut during the rapid postprandial diuresis. The huge blood-meal is pumped into the anterior midgut, during feeding, then modified by diuresis and stored until it is digested.

Invitro effect of Canavalia ensiformis urease and the derived peptide Jaburetox-2Ec on Rhodnius prolixus Malpighian tubules.

Ureases are metalloenzymes that are widespread among plants, fungi and bacteria. Urease isoforms (jack bean urease-JBU and canatoxin) from Canavalia ensiformis seeds are toxic to insects and fungi, suggesting a role in plant defense. The entomotoxic effect is due to the release of a 10-kDa peptide by cathepsin-like enzymes in the insect's midgut.

Effects of selected neuropeptides, mating status and castration on male reproductive tract movements and immunolocalization of neuropeptides in earwigs.

In earwigs, the male reproductive system is complex, comprising accessory glands and long dual intromittent organs for transfer of materials to the female and for removal of rival sperm. We investigated potential factors altering contractions of the male reproductive tracts in vitro. Tracts from 0-day (newly emerged) males displayed relatively little motility in vitro; however, those from 5-day (intermediate stage of sexual maturity) and 8-day (fully mature) males pulsed vigorously.

The distribution and activity of tachykinin-related peptides in the blood-feeding bug, Rhodnius prolixus.

The invertebrate tachykinin-related peptides (TRPs) with the conserved C-terminal sequence FX1GX2Ramide shows sequence similarity to the vertebrate tachykinins after which they are named, and are hypothesized to be ancestrally related. In this study a polyclonal antiserum generated against a locust tachykinin (LomTK I), was used to demonstrate the presence and describe the distribution of LomTK-like immnoreactivity in the CNS and gut of Rhodnius prolixus. Reverse phase high performance liquid chromatography (RP-HPLC) was used in combination with a sensitive radioimmunoassay (RIA) to demonstrate picomolar amounts of immunoreactive material in the CNS, and femptomolar amounts associated with the hindgut.

Contractions associated with the salivary glands of the blood-feeding bug, Rhodnius prolixus: evidence for both a neural and neurohormonal coordination.

The salivary glands of the blood-feeding bug, Rhodnius prolixus, are composed of a single epithelial layer of binucleate cells and a double layer of visceral muscle cells surrounding a large secretory cavity. The saliva contains substances which counteract the hemostasis of the host, and injection of saliva into the host is an essential component of successful and efficient gorging. The muscles surrounding the salivary glands of Rhodnius are under polyneuronal control from the salivary nerve projecting out of the hypocerebral ganglion.