| nmr studies of the dynamics of nitrophorin 2 bound to nitric oxide. | the rhodnius nitrophorins are β-barrel proteins of the lipocalin fold with a heme protruding from the open end of the barrel. they are found in the saliva of the blood-sucking insect rhodnius prolixus, which synthesizes and stores nitric oxide (no) in the salivary glands, where no is bound to iron. no is released by dilution and an increase in ph when the insect spits its saliva into the tissues of a victim, to aid in obtaining a blood meal. in the adult insect, there are four nitrophorins, np1- ... | 2013 | 24116947 |
| investigations of the signaling cascade involved in diuretic hormone stimulation of malpighian tubule fluid secretion in rhodnius prolixus. | in insects, the excretory system is comprised of the malpighian tubules (mts) and the hindgut, which collectively function to maintain ionic and osmotic balance of the haemolymph and rid the organism of toxic compounds or elements in excess. secretion by the malpighian tubules of insects is regulated by a variety of hormones including peptidergic factors as well as biogenic amines. in rhodnius prolixus, two endogenous diuretic hormones have been identified; the biogenic amine serotonin (5-hydrox ... | 2013 | 24080126 |
| expression, purification, and solid-state nmr characterization of the membrane binding heme protein nitrophorin 7 in two electronic spin states. | the nitrophorins (nps) comprise a group of no transporting ferriheme b proteins found in the saliva of the blood sucking insect rhodnius prolixus . in contrast to other nitrophorins (np1-4), the recently identified membrane binding isoform np7 tends to form oligomers and precipitates at higher concentrations in solution. hence, solid-state nmr (ssnmr) was employed as an alternative method to gain structural insights on the precipitated protein. we report the expression and purification of (13)c, ... | 2013 | 24033104 |
| long-term effects and parental rnai in the blood feeder rhodnius prolixus (hemiptera; reduviidae). | rna interference (rnai) has been widely employed as a useful alternative to study gene function in insects, including triatomine bugs. however, several aspects related to the rnai mechanism and functioning are still unclear. the aim of this study is to investigate the persistence and the occurrence of systemic and parental rnai in the triatomine bug rhodnius prolixus. for such, the nitrophorins 1 to 4 (np1-4), which are salivary hemeproteins, and the rhodniin, an intestinal protein, were used as ... | 2013 | 23999100 |
| silencing of maternal heme-binding protein causes embryonic mitochondrial dysfunction and impairs embryogenesis in the blood sucking insect rhodnius prolixus. | the heme molecule is the prosthetic group of many hemeproteins involved in essential physiological processes, such as electron transfer, transport of gases, signal transduction, and gene expression modulation. however, heme is a pro-oxidant molecule capable of propagating reactions leading to the generation of reactive oxygen species. the blood-feeding insect rhodnius prolixus releases enormous amounts of heme during host blood digestion in the midgut lumen when it is exposed to a physiological ... | 2013 | 23986441 |
| circadian regulation of hemolymph and ovarian ecdysteroids during egg development in the insect rhodnius prolixus (hemiptera). | ecdysteroids, classically studied as the molting hormones of insects, occur at lower levels in the adult stage, but their source and significance in adult physiology is debated. in rhodnius prolixus, a blood meal initiates a cycle of egg development and ecdysteroids appeared in the hemolymph within 1-2h of feeding. systematic changes in hemolymph ecdysteroid titer then occurred during egg development. there was a clear circadian rhythm in the hemolymph ecdysteroid titer throughout egg developmen ... | 2013 | 23954834 |
| rhodnius prolixus and rhodnius robustus-like (hemiptera, reduviidae) wing asymmetry under controlled conditions of population density and feeding frequency. | habitat change in rhodnius spp may represent an environmental challenge for the development of the species, particularly when feeding frequency and population density vary in nature. to estimate the effect of these variables in stability on development, the degree of directional asymmetry (da) and fluctuating asymmetry (fa) in the wing size and shape of r. prolixus and r. robustus-like were measured under laboratory controlled conditions. da and fa in wing size and shape were significant in both ... | 2013 | 23938387 |
| perimicrovillar membrane assembly: the fate of phospholipids synthesised by the midgut of rhodnius prolixus. | in this study, we describe the fate of fatty acids that are incorporated from the lumen by the posterior midgut epithelium of rhodnius prolixus and the biosynthesis of lipids. we also demonstrate that neutral lipids (nl) are transferred to the haemolymphatic lipophorin (lp) and that phospholipids remain in the tissue in which they are organised into perimicrovillar membranes (pmms). 3h-palmitic acid added at the luminal side of isolated midguts of r. prolixus females was readily absorbed and was ... | 2013 | 23827998 |
| kinetics and computational studies of ligand migration in nitrophorin 7 and its δ1-3 mutant. | nitrophorins (nps) are nitric oxide (no)-carrying heme proteins found in the saliva of the blood-sucking insect rhodnius prolixus. though np7 exhibits a large sequence resemblance with other nps, two major differential features are the ability to interact with negatively charged cell surfaces and the presence of a specific n-terminus composed of three extra residues (leu1-pro2-gly3). the aim of this study is to examine the influence of the n-terminus on the ligand binding, and the topological fe ... | 2013 | 23624263 |
| the female reproductive system of the kissing bug, rhodnius prolixus: arrangements of muscles, distribution and myoactivity of two endogenous fmrfamide-like peptides. | phalloidin staining f-actin was used to image muscle fiber arrangements present in the reproductive system of the adult female rhodnius prolixus. a mesh of muscle fibers encircles the ovaries whereas a criss-cross pattern of finer muscle fibers covers each ovariole. two layers of muscle fibers (arranged longitudinally and circularly) form the lateral oviducts. the circular layer of muscle fibers extends throughout the common oviduct and spermathecae. a chevron pattern of thicker muscle fibers ma ... | 2014 | 23598080 |
| complexes of ferriheme nitrophorin 4 with low-molecular weight thiol(ate)s occurring in blood plasma. | nitrophorins are proteins occurring in the saliva of the blood-sucking insect rhodnius prolixus to carry no as a vasodilator and blood-coagulation inhibitor into the victim's tissue. it was suggested that the rate of no release can be enhanced by the blood-plasma component l-cysteine [j.m.c.ribeiro, insect biochem. mol. biol. 26 (1996) 899-905]. however, the mechanism of the reaction is not clear. in the attempt to exploit the reaction in detail, complexes of nitrophorin 4 (np4) with the thiols ... | 2013 | 23474537 |
| learning and memory in rhodnius prolixus: habituation and aversive operant conditioning of the proboscis extension response. | it has been largely accepted that the cognitive abilities of disease vector insects may have drastic consequences on parasite transmission. however, despite the research effort that has been invested in the study of learning and memory in haematophagous insects, hitherto few conclusive results have been obtained. adapting procedures largely validated in drosophila, honeybees and butterflies, we demonstrate here that the proboscis extension response (per) of the haematophagous insect rhodnius pro ... | 2013 | 23408803 |
| rhodnius prolixus lipophorin: lipid composition and effect of high temperature on physiological role. | lipophorin is a major lipoprotein that transports lipids in insects. in rhodnius prolixus, it transports lipids from midgut and fat body to the oocytes. analysis by thin-layer chromatography and densitometry identified the major lipid classes present in the lipoprotein as diacylglycerol, hydrocarbons, cholesterol, and phospholipids (pls), mainly phosphatidylethanolamine and phosphatidylcholine. the effect of preincubation at elevated temperatures on lipophorin capacity to deliver or receive lipi ... | 2013 | 23361613 |
| elimination of rhodnius prolixus in el salvador, central america. | epidemiological studies performed in el salvador between 1955-1972 demonstrated a high frequency of two triatomine vectors (triatoma dimidiata and rhodnius prolixus). however, the frequency of r. prolixus decreased by 1976 and this species has not been found since 1995. the main factors influencing the elimination of r. prolixus in el salvador are discussed in this paper. | 2012 | 23295761 |
| insulin-like and testis ecdysiotropin neuropeptides are regulated by the circadian timing system in the brain during larval-adult development in the insect rhodnius prolixus (hemiptera). | insulin-like peptides (ilps) regulate numerous functions in insects including growth, development, carbohydrate metabolism and female reproduction. this paper reports the immunohistochemical localization of ilps in brain neurons of rhodnius prolixus and their intimate associations with the brain circadian clock system. in larvae, three groups of neurons in the protocerebrum are ilp-positive, and testis ecdysiotropin (te) is co-localized in two of them. during adult development, the number of ilp ... | 2012 | 22964530 |
| natural infection of triatomines (hemiptera: reduviidae) by trypanosomatids in two different environments in the municipality of ouro preto do oeste, state of rondônia, brazil. | this study analyzed the occurrence and the contamination of triatomines by trypanosomatids in orbignya speciosa (babassu) specimens in the state of rondônia, brazil, in two different environments (pasture and woods). | 2012 | 22760144 |
| assignment of the 1h nmr resonances of protein residues in close proximity to the heme of the nitrophorins: similarities and differences among the four proteins from the saliva of the adult blood-sucking insect rhodnius prolixus. | the nuclear overhauser effects (noes) observed between heme substituent protons and a small number of nearby protein side chain protons in the water-elimination fourier transform noe spectroscopy (weft-noesy) spectra of high- and low-spin wild-type nitrophorin (np) 2 and its ligand complexes have been analyzed and compared with those observed for the same complexes of wild-type np3. these assignments were made on naturally abundant isotope samples, with the most useful protein side chains being ... | 2012 | 22711329 |
| identification of (l)-3-hydroxykynurenine o-sulfate in the buccal gland secretion of the parasitic lamprey, lethenteron japonicum. | parasitic lampreys are known to secrete proteins having anticoagulant and vasodilator activities from the buccal glands during feeding on their host's blood. however, small molecules in the secretion have never been explored in detail. we examined the secretion of japanese liver lamprey (lethenteron japonicum) for small molecules and found an intensely fluorescent substance upon gel filtration. after purification by anion-exchange chromatography and reversed-phase hplc, structure of the compound ... | 2012 | 22648634 |
| an unusual myosuppressin from the blood-feeding bug rhodnius prolixus. | the myosuppressin (ms) gene was cloned from a central nervous system (cns) cdna library of the hematophagous insect rhodnius prolixus and is predicted to contain two introns and three exons. the mrna transcribed from the myosuppressin gene encodes an 88 amino acid prepropeptide, which results in a mature decapeptide after post-translational modification. when compared with the myosuppressins isolated from other insects, the r. prolixus myosuppressin has a unique amino acid sequence (pqdidhvfmrfa ... | 2012 | 22623197 |
| a caged cyanide. | a photoactivatable caged cyanide, 1-(2-nitrophenyl)ethyl (npe) cyanide, was synthesized, which upon irradiation in the near uv releases cyanide. it is demonstrated that the compound can be used to induce formation of the fe(iii)-cn(-) complex in the heme protein nitrophorin 4 from rhodnius prolixus. | 2012 | 22406687 |
| identification of the native n-terminus of the membrane attaching ferriheme protein nitrophorin 7 from rhodnius prolixus. | all species of the genus rhodnius have a characteristic red coloration in their salivary glands due to the presence of heme proteins. some of these secreted proteins, known as nitrophorins (nps), are responsible for many of the antihemostatic activities of rhodnius saliva such as anticoagulant and antihistamine. several nps have been described (np1-4 and np7), where np7 is the only one with affinity to phospholipid membranes. computational prediction suggested that np7 also has an extended n-ter ... | 2012 | 22349021 |
| nuclear inelastic scattering and mössbauer spectroscopy as local probes for ligand binding modes and electronic properties in proteins: vibrational behavior of a ferriheme center inside a β-barrel protein. | in this work, we present a study of the influence of the protein matrix on its ability to tune the binding of small ligands such as no, cyanide (cn(-)), and histamine to the ferric heme iron center in the no-storage and -transport protein nitrophorin 2 (np2) from the salivary glands of the blood-sucking insect rhodnius prolixus. conventional mössbauer spectroscopy shows a diamagnetic ground state of the np2-no complex and type i and ii electronic ground states of the np2-cn(-) and np2-histamine ... | 2012 | 22295945 |
| crystallization and preliminary x-ray crystallographic analysis of the membrane-binding haemprotein nitrophorin 7 from rhodnius prolixus. | nitrophorins (nitric oxide transport proteins) are haemproteins originating from the blood-feeding insect rhodnius prolixus. they consist of an eight-stranded β-barrel, which classifies them into the lipocalin family. nitrophorin 7 (np7) and the e27v mutant protein np7(e27v) were crystallized at 277 k using the vapour-diffusion method with peg as the precipitating agent. data sets for wild-type np7 and np7(e27v) were collected to 1.80 å resolution from single crystals at 100 k using synchrotron ... | 2012 | 22232167 |
| recent experiments towards a model for fluid secretion in rhodnius upper malpighian tubules (umt). | three different methods have been used to improve a model for fluid secretion in upper malpighian tubules (umt) of the blood sucking insect rhodnius prolixus. (i) in the first, umt double perfusions in 5th instar rhodnius were used to measure their fluid secretion rate. they were stimulated to secrete with 5-ht. double perfusions allowed access separately to the basolateral and the apical cell membranes with pharmacological agents known to block different ion transport functions, namely atpases, ... | 2012 | 22206885 |
| natriuresis and diuretic hormone synergism in r. prolixus upper malpighian tubules is inhibited by the anti-diuretic hormone, rhoprcapa-α2. | insects contain an array of hormones that coordinate the actions of the excretory system to achieve osmotic and ionic balance. in the hematophagous insect, rhodnius prolixus, two diuretic hormones have been identified, serotonin (5ht) and a corticotropin releasing factor-related peptide (rhoprdh), and both lead to an increase in fluid secretion by malpighian tubules (mts). however, only 5ht activates reabsorption by the lower mts to recover k(+) and cl(-). an anti-diuretic hormone (rhoprcapa-α2) ... | 2012 | 22154955 |
| rhythmic release of prothoracicotropic hormone from the brain of an adult insect during egg development. | prothoracicotropic hormone (ptth) is a brain neurohormone that has been studied for over 80 years. the only known target of ptth is the prothoracic glands (pgs) of larvae, which synthesize the insect molting hormones (ecdysteroids) and a massive literature exists on this axis. the pgs degenerate around the time of adult emergence, yet presence of ptth has been reported in the brains of several adult insects. using an in vitro bioassay system, we confirm that ptth is present in the adult female b ... | 2012 | 22079105 |
| cloning of the cdna, localization, and physiological effects of fglamide-related allatostatins in the blood-gorging bug, rhodnius prolixus. | allatostatins (asts) are insect neuropeptides that were first identified as inhibitors of juvenile hormone biosynthesis by the corpora allata. there are three families of asts in insects, defined by their c-terminus conserved regions, one of which is fglamide. here we determine, for the first time in a hemipteran, the complete 1013 bp cdna sequence encoding the rhodnius prolixus fgla/asts (rhopr-fgla/asts), and confirm the transcript size using northern blot. phylogenetic analysis suggests that ... | 2012 | 22061445 |
| learning the way to blood: first evidence of dual olfactory conditioning in a blood-sucking insect, rhodnius prolixus. ii. aversive learning. | after having demonstrated that blood-sucking bugs are able to associate a behaviourally neutral odour (l-lactic acid) with positive reinforcement (i.e. appetitive conditioning) in the first part of this study, we tested whether these insects were also able to associate the same odour with a negative reinforcement (i.e. aversive conditioning). learned aversion to host odours has been repeatedly suggested as a determinant for the distribution of disease vectors among host populations. nevertheless ... | 2011 | 21865516 |
| metamorphosis of a clock: remodeling of the circadian timing system in the brain of rhodnius prolixus (hemiptera) during larval-adult development. | the rhythmic phenomena expressed by organisms change over their lifetimes, but little is known of accompanying reorganization of the central circadian timing system in the brain. especially dramatic changes in overt rhythms and morphology occur during transformation of larval insects into the adult form (metamorphosis). in rhodnius prolixus, both the physiology of metamorphosis and its hormonal control are known in detail. here we report changes in the brain timing system as revealed by pigment ... | 2012 | 21830222 |
| response to heat in rhodnius prolixus: the role of the thermal background. | heat is the principal host-associated cue for the blood-sucking bug rhodnius prolixus. it is both necessary and sufficient to trigger the "proboscis extension response" (per), an essential element of the feeding behaviour of this insect. the aim of this study was to determine whether the temperature of an object itself or the thermal contrast between the object and the environmental background is responsible for triggering the per. thermal stimuli at 25-50°c were presented in thermal environment ... | 2011 | 21806990 |
| adaptation of the repellency response to deet in rhodnius prolixus. | for many years it has been accepted that deet interferes with the detection of odours from the host instead of having a repellent effect. however, recent work showed that deet acts as an odorant molecule and elicits a behavioural response in the absence of other stimuli. therefore, deet must promote some phenomenon connected with the stimuli-sensory system interaction, such as a sensory adaptation, where the sensory system regulates its sensitivity to different stimuli intensities during continu ... | 2011 | 21801727 |
| the gap gene giant of rhodnius prolixus is maternally expressed and required for proper head and abdomen formation. | the segmentation process in insects depends on a hierarchical cascade of gene activity. the first effectors downstream of the maternal activation are the gap genes, which divide the embryo in broad fields. we discovered a sequence corresponding to the leucine-zipper domain of the orthologue of the gene giant (rp-gt) in traces from the genome of rhodnius prolixus, a hemipteran with intermediate germ-band development. we cloned the rp-gt gene from a normalized cdna library and characterized its ex ... | 2012 | 21763688 |
| substrate texture properties induce triatomine probing on bitten warm surfaces. | in this work we initially evaluated whether the biting process of rhodnius prolixus relies on the detection of mechanical properties of the substrate. a linear thermal source was used to simulate the presence of a blood vessel under the skin of a host. this apparatus consisted of an aluminium plate and a nickel-chrome wire, both thermostatized and presented at 33 and 36°c, respectively. to evaluate whether mechanical properties of the substrate affect the biting behaviour of bugs, this apparatus ... | 2011 | 21682881 |
| nitrophorins: nitrite disproportionation reaction and other novel functionalities of insect heme-based nitric oxide transport proteins. | nitrophorins (nps) comprise a unique class of heme proteins used by the blood-sucking insect rhodnius prolixus to deliver the signaling gas molecule no into the blood vessel of a host during feeding. upon no release, histamine can be scavenged by coordination to the heme iron. although the protein is of similar size as the mammalian globin monomers and shares the same cofactor and proximal histidine coordination, nitrophorin structure, in contrast, is almost entirely composed of a β-barrel. comp ... | 2011 | 21491557 |
| the activity of platelet activating factor-acetyl hydrolase (paf-ah) in the salivary glands of rhodnius prolixus. | in this work, we investigated the activity of the platelet activating factor acetyl hydrolase (paf-ah) in the salivary gland homogenates and saliva of rhodnius prolixus. paf-ah activity in the salivary gland homogenates was lower than in the saliva. preliminary characterization of the enzyme demonstrated that it hydrolyzed the substrate 2-thio-paf, was detectable just in 1 pair of salivary gland homogenates in 0.5 ml buffer, and was stable under different conditions. pmsf, tpck, tlck, pepstatin ... | 2011 | 21439293 |
| lipid accumulation and utilization by oocytes and eggs of rhodnius prolixus. | insect eggs must contain the necessary nutrients for embryonic growth. in this article, we investigated the accumulation of triacylglycerol (tag) in growing oocytes and its utilization during embryonic development. tag makes up about 60% of the neutral lipids in oocytes and accumulates as oocytes grow, from 2.2 ± 0.1 µg in follicles containing 1.0 mm length oocytes to 10.2 ± 0.8 µg in 2.0 mm length oocytes. lipophorin (lp), the hemolymphatic lipoprotein, radioactively labeled in free fatty acid ... | 2011 | 21308762 |
| 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. 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 ... | 2011 | 21228196 |
| 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. multiple peptides predicted from the ki ... | 2011 | 20934474 |
| calreticulin expression levels and endoplasmic reticulum during late oogenesis and early embryogenesis of rhodnius prolixus stahl. | this study reports the cloning, expression analysis and localization of calreticulin (crt) in the endoplasmic reticulum (er) during late oogenesis and early embryogenesis of the insect rhodnius prolixus. crt was cloned and sequenced from cdna extracted from unfertilized eggs. real-time pcr showed that crt expression remains at lower levels during late oogenesis when compared to vitellogenic oocytes or day 0 laid fertilized eggs. immunofluorescence microscopy showed that this protein is located i ... | 2011 | 20857219 |
| isolation and characterization of the cdna encoding dh(31) in the kissing bug, rhodnius prolixus. | rhodnius prolixus undergoes a period of rapid diuresis after ingesting large blood meals. neurohormones with either diuretic or anti-diuretic activity control diuresis by acting on several tissues including the malpighian tubules. one of the neurohormones that potentially plays a role in diuresis is diuretic hormone 31 (dh(31)) which belongs to the insect calcitonin-like family of diuretic hormones. here we determine the complete cdna sequences of three rhopr-dh(31) splice variants (rhopr-dh(31) ... | 2011 | 20797422 |
| unprecedented peroxidase-like activity of rhodnius prolixus nitrophorin 2: identification of the [feiv=o por•]+ and [feiv=o por](tyr38•) intermediates and their role(s) in substrate oxidation. | we have identified a novel enzymatic reaction for nitrophorin 2 (np2), a heme protein previously characterized as a nitric oxide carrier in the saliva of the rhodnius prolixus insect. np2 exhibited levels of peroxidase activity comparable to those of the bifunctional peroxidases (katgs), despite their heme pocket structural differences (heme ruffling, tyr38 and tyr85 in hydrogen bonding interactions with the propionates in np2). the intermediates of the peroxidase-like reaction of np2 were ident ... | 2010 | 20726527 |
| formation of the complex of nitrite with the ferriheme b beta-barrel proteins nitrophorin 4 and nitrophorin 7. | the interaction of ferriheme proteins with nitrite has recently attracted interest as a source for no or other nitrogen oxides in mammalian physiology. however, met-hemoglobin (methb), which was suggested as a key player in this process, does not convert nitrite unless small amounts of no are added in parallel. we have recently reported that, in contrast, nitrophorins (nps) convert nitrite as the sole substrate to form no even at ph 7.5, which is an unprecedented case among ferrihemes [he, c., a ... | 2010 | 20524697 |
| phenol oxidases from rhodnius prolixus: temporal and tissue expression pattern and regulation by ecdysone. | rhodnius prolixus 5th instar nymphs have significant po enzymatic activity in the anterior midgut, fat body and hemolymph. the tissue with the major amount of po activity is the anterior midgut while those with higher specific activities are the fat body and hemolymph. in this work the temporal pattern of po enzymatic activity in different tissues was investigated. in fat body, po peaks occur at 7, 12 and 16 days after a blood meal. in hemolymph, po diminishes until day 7, and then recovers by d ... | 2010 | 20361973 |
| jack bean urease alters serotonin-induced effects on rhodnius prolixus anterior midgut. | urease isoforms from jack bean seeds are toxic to insects, and this entomotoxic effect is mostly due to the release of a peptide by insect digestive enzymes. we previously demonstrated that jack bean urease (jbu) has antidiuretic effects on rhodnius prolixus malpighian tubules, decreasing the serotonin-stimulated secretion of fluid. now, we evaluate the toxicity of the intact jbu and its effect on r. prolixus anterior midgut, to further elucidate the mechanism of action of jbu in insects. jbu de ... | 2010 | 20223243 |
| the circadian timing system in the brain of the fifth larval instar of rhodnius prolixus (hemiptera). | the brain of larval rhodnius prolixus releases neurohormones with a circadian rhythm, indicating that a clock system exists in the larval brain. larvae also possess a circadian locomotor rhythm. the present paper is a detailed analysis of the distribution and axonal projections of circadian clock cells in the brain of the fifth larval instar. clock cells are identified as neurons that exhibit circadian cycling of both per and tim proteins. a group of eight lateral clock neurons (lns) in the prox ... | 2010 | 20151359 |
| serotonin regulates an acyl-coa-binding protein (acbp) gene expression in the midgut of rhodnius prolixus. | acyl-coa esters have many intracellular functions, acting as energy source, substrate for metabolic processes and taking part in cell signaling. the acyl-coa-binding protein (acbp), a highly conserved 10 kda intracellular protein, binds long- and medium-chain acyl-coa esters with very high affinity, directing them to specific metabolic routes and protecting them from hydrolysis. an acbp gene sequence was identified in the genome of rhodnius prolixus. this acbp gene (rpacbp-1) was expressed in al ... | 2010 | 20079838 |
| effects of the cyclopeptide mycotoxin destruxin a on the malpighian tubules of rhodnius prolixus (stål). | the production of peptide toxins by entomopathogenic fungi during the infection process plays critical roles in pathogenesis. to gain insight into the mechanism of action of these mycotoxins on insect internal organs, we have evaluated the effects of destruxin a, a cyclic peptide produced by metarhizium anispliae, on rhodnius prolixus malpighian tubules measuring fluid secretion rate, transepithelial electrical potential (tep), ph and ion composition of secreted fluid, and atp content. destruxin ... | 2010 | 20060849 |
| on the physico-chemical and physiological requirements of hemozoin formation promoted by perimicrovillar membranes in rhodnius prolixus midgut. | triatomine insects are obligatory blood-feeders that detoxify most of the hemoglobin-derived heme through its crystallization into hemozoin (hz). previous evidence demonstrates the key role of midgut perimicrovillar membranes (pmvm) on heme crystallization in triatomines. here, we investigated some of the physico-chemical and physiological aspects of heme crystallization induced by rhodnius prolixus pmvm. hz formation in vitro proceeded optimally at ph 4.8 and 28 degrees c, apparently involving ... | 2010 | 20060043 |
| 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. two antidiuretic strategies have been described. the first antidiuretic mechanism involves the reabsorption of fluid from the primary urine in the hindgut. mo ... | 2010 | 20007522 |
| inorganic polyphosphate inhibits an aspartic protease-like activity in the eggs of rhodnius prolixus (stahl) and impairs yolk mobilization in vitro. | inorganic polyphosphate (poly p) is a polymer of phosphate residues that has been shown to act as modulator of some vertebrate cathepsins. in the egg yolk granules of rhodnius prolixus, a cathepsin d is the main protease involved in yolk mobilization and is dependent on an activation by acid phosphatases. in this study, we showed a possible role of poly p stored inside yolk granules on the inhibition of cathepsin d and arrest of yolk mobilization during early embryogenesis of these insects. enzy ... | 2010 | 19957302 |
| a second gene encodes the anti-diuretic hormone in the insect, rhodnius prolixus. | in the haematophagous insect, rhodnius prolixus, a rapid diuresis following engorgement of vertebrate blood is under the control of two main diuretic hormones: a corticotropin-releasing factor (crf)-related peptide andserotonin (5ht). a cap2b (capa)-related peptide is involved in the termination of this diuresis, and we have recently identified a gene, now referred to as rhoprcapa-alpha, encoding capa peptides in r. prolixus. here we identify a second gene, rhoprcapa-beta, which also encodes cap ... | 2010 | 19931590 |
| ecdysteroid receptor (ecr) is associated with microtubules and with mitochondria in the cytoplasm of prothoracic gland cells of rhodnius prolixus (hemiptera). | we have shown previously that ecr in larval rhodnius is present in the cytoplasm of various cell types and undergoes daily cycling in abundance in the cytoplasm (vafopoulou and steel, 2006. cell tissue res 323:443-455). it is unknown which organelles are associated with ecr. here, we report that cytoplasmic ecr in prothoracic gland cells is associated with both microtubules and mitochondria, and discuss the implications for both nuclear and non-genomic actions of ecr. ecr was localized immunohis ... | 2009 | 19847923 |
| cloning and characterization of dorsal homologues in the hemipteran rhodnius prolixus. | rhodnius prolixus is an ancient haematophagous hemipteran insect capable of mounting a powerful immune response. this response is transcriptionally regulated in part by transcription factors of the rel/nuclear factor kappa b (rel/nf-kappab) family. we have cloned and characterized three members of this transcription factor family in this insect. dorsal 1a is primarily expressed in early developmental stages. in contrast, dorsal 1b and 1c, both differentially spliced products of dorsal 1a, are ex ... | 2009 | 19754745 |
| behavioural and physiological state dependency of host seeking in the blood-sucking insect rhodnius prolixus. | vertebrate blood is essential for the growth and the reproduction of haematophagous insects. provided that hosts play the double role of food sources and predators, feeding on their blood exposes these insects to a high predation risk. therefore, it is expected that host seeking occurs only when insects need to feed. in the present study, we analyse how the feeding status affects the response to host-associated cues in the blood-sucking insect rhodnius prolixus. we show that the responsiveness t ... | 2009 | 19617431 |
| functional anatomy of vagina muscles in the blood-feeding insect, rhodnius prolixus. | the physiology of the muscles associated with the vagina in the blood-feeding insect, rhodnius prolixus stal, was investigated with the use of methylene blue staining to visualize the anatomy, and a micro force transducer to record spontaneous and neurally-evoked contractions. the vagina is associated with a dorsal muscle and a set of paired lateral muscles. the dorsal muscle extends from the base of the common oviduct to apodemes located laterally on sternite viii, the first genital segment. th ... | 2009 | 19573623 |
| transitions in insect respiratory patterns are controlled by changes in metabolic rate. | we examined the respiratory patterns of rhodnius prolixus and gromphadorhina portentosa as metabolic rates varied with temperature to determine whether insects transition from discontinuous (dgc), cyclical and continuous respiration as a response to increasing aerobic demand. using flow through respirometry we: (1) determined the effects of temperature on metabolic rate; (2) objectively defined periods of spiracular closure; (3) observed whether there was a correlation between metabolic rate and ... | 2010 | 19523955 |
| peptides and serotonin control feeding-related events in rhodnius prolixus. | rhodnius prolixus periodically gorges on a blood meal that could compromise salt and water balance. this, however, is prevented by rapid production of urine within minutes of feeding. the malpighian tubules increase their rate of secretion 1,000 fold leading to the production of a hypo-osmotic urine that is high in nacl content. feeding and post-prandial diuresis in r. prolixus are tightly coordinated events, involving a variety of neurons within the central nervous system. the present review co ... | 2009 | 19482642 |
| 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 ... | 2009 | 19408362 |
| protein dynamics of a beta-sheet protein. | rhodnius prolixus nitrophorin 4 (abbreviated np4) is an almost pure beta-sheet heme protein. its dynamics is investigated by x-ray structure determination at eight different temperatures from 122 to 304 k and by means of mössbauer spectroscopy. a comparison of this beta-sheet protein with the pure alpha-helical protein myoglobin (abbreviated mbmet) is performed. the mean square displacement derived from the mössbauer spectra increases linearly with temperature below a characteristic temperature ... | 2009 | 19271215 |
| assignment of ferriheme resonances for high- and low-spin forms of nitrophorin 3 by h and c nmr spectroscopy and comparison to nitrophorin 2: heme pocket structural similarities and differences. | nitrophorin 3 (np3) is the only one of the four major no-binding heme proteins found in the saliva of the blood-sucking insect rhodnius prolixus (also called the kissing bug) for which it has not been possible to obtain crystals of diffraction quality for structure determination by x-ray crystallography. thus we have used nmr spectroscopy, mainly of the hyperfine-shifted ferriheme substituent resonances, to learn about the similarities and differences in the heme pocket and the iron active site ... | 2008 | 19262680 |
| effect of mutation of carboxyl side-chain amino acids near the heme on the midpoint potentials and ligand binding constants of nitrophorin 2 and its no, histamine, and imidazole complexes. | nitrophorins (nps) are a group of no-carrying heme proteins found in the saliva of a blood-sucking insect from tropical central and south america, rhodnius prolixus, the "kissing bug". no is kept stable for long periods of time by binding it as an axial ligand to a ferriheme center. the fact that the nitrophorins are stabilized as fe(iii)-no proteins is a unique property because most heme proteins are readily autoreduced by excess no and bind no to the fe(ii) heme irreversibly (k(d)s in the pico ... | 2009 | 19175316 |
| metabolic rate controls respiratory pattern in insects. | the majority of scientific papers on the subject of respiratory patterns in insects have dealt with the discontinuous gas-exchange cycle (dgc). the dgc is characterized by the release of bursts of co(2) from the insect, followed by extended periods of spiracular closure. several hypotheses have been put forward to explain the evolutionary origin and physiological function of this unusual respiratory pattern. we expand upon one of these (the oxidative damage hypothesis) to explain not only the oc ... | 2009 | 19151217 |
| neuroendocrine control of ionic homeostasis in blood-sucking insects. | the pioneering work of simon maddrell established that the rapid postprandial diuresis of the haematophagous insect rhodnius prolixus is controlled by a diuretic hormone and demonstrated the role of the malpighian tubules in meeting the volumic, osmotic and ionic challenges posed by an enormous blood meal. a number of diuretic and antidiuretic hormones that control secretion of primary urine by malpighian tubules have now been identified, but little is known of the interplay between these hormon ... | 2009 | 19151213 |
| too much of a good thing: how insects cope with excess ions or toxins in the diet. | much of our understanding of the ionoregulatory and excretory physiology of blood-feeding insects can be traced to a series of papers by simon maddrell and colleagues in the 1970s and 1980s. these studies of the malpighian (renal) tubules of rhodnius prolixus revealed a number of physiological adaptations to the short-term and long-term stresses associated with blood feeding. more recent electrophysiological studies using voltage- and ion-selective microelectrodes have extended our understanding ... | 2009 | 19151211 |
| laboratory evaluation of the effects of triflumuron on the development of rhodnius prolixus nymph. | studies were carried out to evaluate the efficacy of the growth regulator, triflumuron (tfm) (starycide sc 480 bayer), for disrupting the development of rhodnius prolixus fifth-instar nymph by oral, topical or continuous treatment. all treatments were able to induce high levels of mortality, delay development and molt inhibition. oral treatment induced molt inhibition in all insects that survived at doses of 0.25, 0.50 and 5.0 mg/ml of a blood meal. the highest levels of both mortality in 24 h a ... | 2008 | 19148427 |
| a one-residue switch reverses the orientation of a heme b cofactor. investigations of the ferriheme no transporters nitrophorin 2 and 7 from the blood-feeding insect rhodnius prolixus. | this study represents the identification of a single amino acid residue that has the major responsibility for the isomeric orientation of a heme b cofactor in a ferriheme protein. the insertion of hemin b into the asymmetric environment of a protein pocket facilitates two cofactor orientations, a and b, which is often called "heme rotational disorder". the proteins studied herein are nitrophorins, a class of ferriheme proteins found in the saliva of the blood-sucking insect rhodnius prolixus, in ... | 2009 | 19140692 |
| ecology of north american triatominae. | in all, 40 native triatomine species and subspecies occur in na, belonging to six genera from the triatomini (triatoma, paratriatoma, panstrongylus, dipetalogaster, belminus, eratyrus), and one genus from the rhodniini (represented by one non-native species rhodnius prolixus, formerly occurring exclusively in domestic habitats); 28 species are found exclusively in mexico (and/or central america), eight are shared between the united states (us) and mexico, and four occur exclusively in the us. th ... | 2009 | 19084490 |
| antennal pathways in the central nervous system of a blood-sucking bug, rhodnius prolixus. | the haematophagous bug rhodnius prolixus has been a model system in insect physiology for a long time. recently, several studies have been devoted to its sensory systems, including olfaction. however, few data are available on the basic organisation of the nervous system in this species. by means of neuronal backfills, histology, confocal microscopy and three-dimensional reconstruction methods, we have characterized the projection patterns of antennal sensory neurons within the central nervous s ... | 2009 | 18809510 |
| temporal modulation and adaptive control of the behavioural response to odours in rhodnius prolixus. | it has been demonstrated in several insect species that a circadian clock makes the whole of antennal chemoreceptors more sensitive during a particular temporal window every day. this assessment raises the question about how insects exhibiting bimodal activity handle their sensitivity to odours which are relevant at different moments of the day. to shed some light on this problem, we studied in rhodnius prolixus the daily dynamics of their responsiveness to co(2) (host-associated cue) and aggreg ... | 2008 | 18692504 |
| cytochemical characterization of microvillar and perimicrovillar membranes in the posterior midgut epithelium of rhodnius prolixus. | perimicrovillar membranes (pmm) are structures present on the surface of midgut epithelial cells of the hematophagous insect, rhodnius prolixus. they cover the microvilli and are especially evident 10 days after blood meal, providing the compartmentalization of the enzymatic processes in the intestinal microenvironment. using an enzyme cytochemical approach, mg2+-atpase and ouabain-sensitive na+k+-atpase activities were observed in the plasma (or microvillar) membrane (mm) of midgut cells and in ... | 2009 | 18602023 |
| assignment of the ferriheme resonances of high- and low-spin forms of the symmetrical hemin-reconstituted nitrophorins 1-4 by 1h and 13c nmr spectroscopy: the dynamics of heme ruffling deformations. | the four major nitrophorins (nps) of the adult blood-sucking insect rhodnius prolixus have been reconstituted with the "symmetrical hemin" 2,4-dimethyldeuterohemin, and their nmr spectra have been investigated as the high-spin (s=5/2) aqua and low-spin (s=1/2) n-methylimidazole (nmeim) and cyanide complexes. the nmeim complexes allow assignment of the high-spin hemin resonances by saturation transfer difference spectroscopy. the cyanide complexes were investigated as paramagnetic analogues of th ... | 2008 | 18458965 |
| dynamics of lipid accumulation by the fat body of rhodnius prolixus: the involvement of lipophorin binding sites. | in insects, lipids are stored in the fat body, mainly as triacylglycerol (tag). in rhodnius prolixus, a hematophagous hemipteran, lipids are accumulated after blood meal to be used later on. in adult females, at the second day after feeding, the amount of tag was 57+/-17 microg/fat body, it increased almost five times and at fourth day it was 244+/-35 microg/fat body. tag content remained constant until day 13, but it then decreased and, at day 20th it was very low (31+/-4.9 microg/fat body). ra ... | 2008 | 18395740 |
| metasternal gland volatiles and sexual communication in the triatomine bug, rhodnius prolixus. | twelve compounds produced by the metasternal glands (mgs) of the triatomine bug rhodnius prolixus were identified by solid phase microextraction (spme) combined with coupled gas chromatography-mass spectrometry (gc-ms) using achiral and chiral columns. all substances were ketones or alcohols, and the same compound profile was found in the secretions produced by either sex. the most abundant compounds were 2-methyl-3-buten-2-ol, (2s)-pentanol, (3e)-2-methyl-3-penten-2-ol, and (2r/2s)-4-methyl-3-p ... | 2008 | 18317844 |
| amino acid sequence and biological activity of a calcitonin-like diuretic hormone (dh31) from rhodnius prolixus. | diuresis in the blood-gorging hemipteran rhodnius prolixus is under neurohormonal control and involves a variety of processes and tissues. these include ion and water movement across the epithelium of the crop and the malpighian tubules, and muscle contractions of the crop, hindgut and dorsal vessel, which facilitate mixing of the blood-meal, mixing of the haemolymph, as well as the expulsion of waste. one of the neurohormones that might play a role in this rapid diuresis belongs to the calciton ... | 2008 | 18203994 |
| characterization of neuropeptide f-like immunoreactivity in the blood-feeding hemipteran, rhodnius prolixus. | the invertebrate neuropeptide y (npy) homolog, neuropeptide f (npf), has been characterized for a wide range of invertebrate phyla, including platyhelminthes, molluscs, and arthropods. current hypotheses suggest that npf may be capable of regulating responses to diverse external cues related to nutritional status and feeding. the qualitative and quantitative distribution of an npf-like peptide in fifth instar rhodnius prolixus was undertaken using an antiserum raised against drosophila npf. immu ... | 2008 | 18201798 |
| decrease in deet repellency caused by nitric oxide in rhodnius prolixus. | n,n-diethyl-3-methylbenzamide (deet) is widely used as an insect repellent; however, little is known about its mode of action. on the other hand, nitric oxide (no) participates in the olfaction transduction pathway of insects. in this work, nitroso-acetyl-cysteine (snac), a nitric oxide donor, or dibutyril-cyclic-gmp (db-cgmp), the cyclic nucleotide analog, were applied on fifth instar nymphs of rhodnius prolixus before exposing them to deet, to obtain information about the possible role of no/c ... | 2008 | 18088059 |
| carbohydrate accumulation and utilization by oocytes of rhodnius prolixus. | the processes of accumulation and mobilization of carbohydrate stores in eggs of rhodnius prolixus were analyzed. during oogenesis, the total amounts of glycogen, glucose, and trehalose increased with an accumulation of proteins, especially when oocytes grew from 1.0 to 1.5 mm in length. at 2.0 mm length, when oocytes were ready for oviposition, nutrient reserves did not increase appreciably and trehalose content decreased. mating did not affect the final content of carbohydrates or proteins in ... | 2008 | 18064701 |
| spectroscopic and functional characterization of nitrophorin 7 from the blood-feeding insect rhodnius prolixus reveals an important role of its isoform-specific n-terminus for proper protein function. | nitrophorins (nps) are a class of no-transporting and histamine-sequestering heme b proteins that occur in the saliva of the bloodsucking insect rhodnius prolixus. a detailed study of the newly described member, np7, is presented herein. no association constants for np7 [kiii(eq)(no)] reveal a drastic change when the ph is varied from 5.5 (reflecting the insect's saliva) to slightly above plasma ph (7.5) (>10(9) m-1 --> 4.0 x 10(6) m-1); thus, the protein promotes the storage of no in the insect ... | 2007 | 17958381 |
| effects of retinoids and juvenoids on moult and on phenoloxidase activity in the blood-sucking insect rhodnius prolixus. | retinoic acid and insect juvenile hormone (jh) are structurally related terpenoids which are widespread in nature and are involved in many biological events such as morphogenesis, embryogenesis and cellular differentiation. here, we investigated the effects of the retinoids 9-cis retinoic acid (9cisra), all trans retinol (atroh), all trans retinoic acid (atra) and the juvenoids methoprene (met) and jh injection on moult and on phenoloxidase activity in the blood-sucking insect rhodnius prolixus. ... | 2007 | 17686447 |
| neuroanatomical relations of prothoracicotropic hormone neurons with the circadian timekeeping system in the brain of larval and adult rhodnius prolixus (hemiptera). | this paper reports the localization in the rhodnius prolixus brain of neurons producing the key neuropeptide that regulates insect development, prothoracicotropic hormone (ptth) and describes intimate associations of the ptth neurons with the brain circadian timekeeping system. immunohistochemistry and confocal laser scanning microscopy revealed that the ptth-positive neurons in larvae are located in a single group in the lateral protocerebrum. their number increases from two in the last larval ... | 2007 | 17534946 |
| perimicrovillar membranes promote hemozoin formation into rhodnius prolixus midgut. | rhodnius prolixus is a hematophagous insect that ingests large quantities of blood in each blood-feeding session. this ingested blood provides important nutrients to sustain the insect's oogenesis and metabolic pathways. during the digestive process, however, huge amounts of heme are generated as a consequence of the hemoglobin breakdown. heme is an extremely dangerous molecule, since it can generate reactive oxygen species in the presence of oxygen that impair the normal metabolism of the insec ... | 2007 | 17517329 |
| rhodnius prolixus malpighian tubules and control of diuresis by neurohormones. | rhodnius prolixus malpighian tubules (mts) are a good model for fluid and ion secretion studies in view of the dramatic postprandial diuresis, which follows its massive blood meals. ingestion of a blood meal equals to 10-12 times their initial body mass, leads to rapid activation of high output by excretory system, which eliminates 40-50% of the fluid mass. secretion of ions and water is stimulated 1000-fold by serotonin and diuretic hormone. these hormones cooperate synergistically to activate ... | 2007 | 17401478 |
| allosteric regulation of 6-phosphofructo-1-kinase activity of fat body and flight muscle from the bloodsucking bug rhodnius prolixus. | 6-phosphofructo-1-kinase (phosphofructokinase; pfk) activity from rhodnius prolixus, a haematophagous insect which is usually a poor flyer, was measured and compared in two metabolically active tissues - flight muscle and fat body. the activity of this important regulatory glycolytic enzyme was much more pronounced in muscle (15.1 +/- 1.4 u/mg) than in fat body extracts (3.6+/-0.4 u/mg), although the latter presented higher levels of enzyme per protein content, as measured by western-blotting. m ... | 2007 | 17401475 |
| calcium-regulated fusion of yolk granules is important for yolk degradation during early embryogenesis of rhodnius prolixus stahl. | this study examined the process of membrane fusion of yolk granules (ygs) during early embryogenesis of rhodnius prolixus. we show that eggs collected at days 0 and 3 after oviposition contain different populations of ygs, for example day-3 eggs are enriched in large ygs (lygs). day-3 eggs also contain the highest free [ca(2+)] during early embryogenesis of this insect. in vitro incubations of day-0 ygs with [ca(2+)] similar to those found in day-3 eggs resulted in the formation of lygs, as obse ... | 2007 | 17170157 |
| the interaction of feeding and mating in the hormonal control of egg production in rhodnius prolixus. | the evidence relating feeding and mating to hormonal control of egg production in rhodnius prolixus is reviewed from two perspectives. it identifies crucial areas in which information is lacking, and it attempts to relate the findings, most of which have been obtained on laboratory colonies isolated for many years, to the sylvan life of the insect as an opportunistic micropredator. | 2007 | 17126364 |
| flight-oogenesis syndrome in a blood-sucking bug: biochemical aspects of lipid metabolism. | lipophorin (lp), either labeled in diacylglycerol moiety with [(3)h]-palmitic acid or in phospholipid moiety with (32)pi, was injected into rhodnius prolixus females. insects were induced to flight for different times. in just a few minutes of flight, the transfer of radioactivity to ovaries decreased, accompanied by its increase to flight muscles. after one hour of flight, lp density was higher (1.132 g/ml) than before flight (1.116 g/ml). lp purified from insects after flight was analyzed by g ... | 2006 | 16933278 |
| fifth instar experience reduces aversiveness of the plant extract ruda (ruta graveolens) in the adult triatomine rhodnius prolixus stal 1859. | | 2006 | 16859109 |
| the haemoxisome: a haem-iron containing structure in the rhodnius prolixus midgut cells. | rhodnius prolixus midgut was analysed using transmission electron microscopy and electron spectroscopic imaging in order to localize the cellular structures involved in haem metabolism. in the posterior midgut, special cellular electron-dense structures were observed. these structures are here designated haemoxisomes. haemoxisomes are present in the epithelial cells at various time points after a blood meal. several days after the blood meal, some of them become less electron-dense. by electron ... | 2006 | 16713601 |
| antihemostatic molecules from saliva of blood-feeding arthropods. | the ability to feed on vertebrate blood has evolved many times in various arthropod clades. each time this trait evolves, novel solutions to the problem posed by vertebrate hemostasis are generated. consequently, saliva of blood-feeding arthropods has proven to be a rich source of antihemostatic molecules. vasodilators include nitrophorins (nitric oxide storage and transport heme proteins), a variety of peptides that mimic endogenous vasodilatory neuropeptides, and proteins that catabolize or se ... | 2005 | 16707932 |
| circadian orchestration of developmental hormones in the insect, rhodnius prolixus. | this review presents a new perspective on the circadian regulation and functions of insect developmental hormones. in rhodnius prolixus (hemiptera), the brain neuropeptide prothoracicotropic hormone (ptth) is released with a circadian rhythm that is controlled by paired photosensitive clocks in the brain. these clocks comprise the dorsal and lateral per/tim clock neurons known to regulate behavioral rhythms in drosophila. axons of ptth and clock cells make close contact. photosensitive per/tim c ... | 2006 | 16702005 |
| electrochemical gradients for na+, k+, cl- and h+ across the apical membrane in malpighian (renal) tubule cells of rhodnius prolixus. | measurements of intracellular and luminal ion activities as well as membrane potential were used to calculate electrochemical gradients for cl-, na+, k+ and h+ across the apical membrane during fluid secretion by malpighian tubules of rhodnius prolixus. the results show that the contribution of na+/h+ and/or k+/h+ exchangers to fluid secretion is feasible both in unstimulated and serotonin-stimulated tubules. similarly, the electrochemical potential for cl- is consistent with the passive movemen ... | 2006 | 16651561 |
| a secreted salivary inositol polyphosphate 5-phosphatase from a blood-feeding insect: allosteric activation by soluble phosphoinositides and phosphatidylserine. | type ii inositol polyphosphate 5-phosphatases (ipps) act on both soluble inositol phosphate and phosphoinositide substrates. in many cases, these enzymes occur as multidomain proteins in which the ipp domain is linked to lipid-binding or additional catalytic domains. rhodnius prolixus ipprp exists as an isolated ipp domain which is secreted into the saliva of this blood-feeding insect. it shows selectivity for soluble and lipid substrates having a 1,4,5-trisphosphate substitution pattern while o ... | 2006 | 16634626 |
| oligomerization of nitrophorins. | rhodnius prolixus is a blood-sucking insect that uses a mixture of nitrophorin (np) proteins to deliver nitric oxide (no) from the insect saliva to the hosts via a ferric heme coordinated to the protein, causing vasodilatation and anticoagulation to support their feeding. r. prolixus nps 1-4 are very similar proteins ( approximately 20 kda) with different no affinities for stepwise no release triggered by ph increase and histamine binding in hosts. ultra-high-resolution x-ray structures of nativ ... | 2006 | 16574056 |
| distribution, activity and evidence for the release of an anti-diuretic peptide in the kissing bug rhodnius prolixus. | in the haematophagous insect rhodnius prolixus, diuresis is accomplished through the combined actions of peptidergic diuretic hormones and 5-ht released from neurohaemal sites on the abdominal nerves. preliminary work on anti-diuresis in this blood-feeder, previously believed to occur through a decrease in the levels of the diuretic factors, indicates that an anti-diuretic hormone, with properties similar to cap2b (pelyafprvamide; recently renamed mas-capa-1), might also be present in r. prolixu ... | 2006 | 16481579 |
| ecto-nucleotidase activities in the fat body of rhodnius prolixus. | in this study, we describe the ability of intact fat body of an insect, rhodnius prolixus, to hydrolyze extracellular atp. in these fat bodies, the atp hydrolysis was low in the absence of any divalent metal, and was stimulated by mgcl(2). both activities (in the absence or presence of mgcl(2)) were linear with time for at least 30 min. in order to confirm the observed nucleotidase activities as ecto-nucleotidases, we used an impermeant inhibitor, dids (4, 4'-diisothiocyanostylbene 2'-2'-disulfo ... | 2006 | 16380977 |
| serotonin: a coordinator of feeding-related physiological events in the blood-gorging bug, rhodnius prolixus. | rhodnius prolixus is an obligatory blood-feeder that can ingest blood meals of up to 10 times its mass. rapid production of urine commences within 2-3 min of the start of feeding in order to eliminate the load of water and salts, and so there is an increase of malpighian tubule secretion greater than 1,000 fold in response to feeding. feeding and post-prandial diuresis in rhodnius are highly coordinated events, including for example, host recognition, probing, injection of saliva, cuticle plasti ... | 2006 | 16377224 |
| ecdysteroid hormone nuclear receptor (ecr) exhibits circadian cycling in certain tissues, but not others, during development in rhodnius prolixus (hemiptera). | the insect moulting hormones, viz. the ecdysteroids, regulate gene expression during development by binding to an intracellular protein, the ecdysteroid receptor (ecr). in the insect rhodnius prolixus, circulating levels of ecdysteroids exhibit a robust circadian rhythm. this paper demonstrates associated circadian rhythms in the abundance and distribution of ecr in several major target tissues of ecdysteroids, but not in others. quantitative analysis of immunofluorescence images obtained by con ... | 2006 | 16323012 |
| ultrahigh resolution structures of nitrophorin 4: heme distortion in ferrous co and no complexes. | nitrophorin 4 (np4), a nitric oxide (no)-transport protein from the blood-sucking insect rhodnius prolixus, uses a ferric (fe3+) heme to deliver no to its victims. no binding to np4 induces a large conformational change and complete desolvation of the distal pocket. the heme is markedly nonplanar, displaying a ruffling distortion postulated to contribute to stabilization of the ferric iron. here, we report the ferrous (fe2+) complexes of np4 with no, co, and h2o formed after chemical reduction o ... | 2005 | 16171383 |
| testis ecdysiotropic peptides in rhodnius prolixus: biological activity and distribution in the nervous system and testis. | in rhodnius prolixus, testes from both pharate adult and adult males are shown to produce and release ecdysteroids in vitro. proteinaceous brain extracts from these stages caused stimulation of ecdysteroid production by testes of unfed adults. therefore, the brain of rhodnius contains peptides with testis ecdysiotropic activity. the lymantria testis ecdysiotropin (lte) also stimulated the in vitro production of ecdysteroids by unfed adult testis but had no stimulatory effect on prothoracic gland ... | 2005 | 16139295 |
| nitrophorin synthesis is modulated by protein kinase ck2. | rhodnius prolixus is a blood-sucking bug whose saliva contains a family of nitric oxide-carrying proteins named nitrophorins (nps). saliva is injected into the host bloodstream during insect feeding. nitric oxide is then released from nps and will act on vascular smooth muscle, promoting vasodilation. epithelial cells of salivary glands then undergo a massive synthesis of antihemostatics including nps which produces saliva for the next blood meal. here, we demonstrate the transient activation of ... | 2005 | 16099432 |