Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
|---|
| exploring the role of insect host factors in the dynamics of trypanosoma cruzi-rhodnius prolixus interactions. | members of the subfamily triatominae, family reduviidae, comprise a large number of insect species of which some are vectors of trypanosoma cruzi, the causative agent of chagas' disease. this article outlines research on the process of transformation and the dynamics of developmental stages of trypanosoma cruzi in the triatomine insect hosts. special attention is given to the interactions of parasites with gut molecules, and the gut environment, and with host developmental physiology and intesti ... | 2007 | 17141801 |
| trypanosoma cruzi: attachment to perimicrovillar membrane glycoproteins of rhodnius prolixus. | studies were carried out to identify proteins involved in the interface of trypanosoma cruzi with the perimicrovillar membranes (pmm) of rhodnius prolixus. video microscopy experiments demonstrated high level of adhesion of t. cruzi dm 28c epimastigotes to the surface of posterior midgut cells of non-treated r. prolixus. the parasites however were unable to attach to gut cells obtained from decapitated or azadirachtin-treated insects. the influence of carbohydrates on the adhesion to insect midg ... | 2007 | 17250827 |
| replication of flock house virus in three genera of medically important insects. | flock house virus (family nodaviridae, genus alphanodavirus, fhv) was originally isolated from grass grubs costelytra zealandica (white) (coleoptera: scarabaeidae) in new zealand and belongs to a family of divided genome, plus-sense rna insect viruses. fhv replicates in insects, a nematode, plants, and yeast. we previously reported replication of fhv in four genera of mosquitoes and expression of green fluorescent protein in aedes aegypti (l.) produced by an fhv-based vector. we report here that ... | 2007 | 17294927 |
| morphometric evidence for a possible role of rhodnius prolixus from palm trees in house re-infestation in the state of barinas (venezuela). | the main vector of chagas disease in venezuela is rhodnius prolixus. specimens of rhodnius sp., identified elsewhere as r. prolixus by molecular tools, were collected in barinas state (venezuela) before insecticide application, and compared by morphometric techniques with post-spraying, re-infesting insects after control. geometric morphometry was applied, allowing separate analyses of shape and size. the idea of a single species sharing silvatic and domestic/peri-domestic ecotopes was supported ... | 2007 | 17306204 |
| trypanosoma cruzi: involvement of glycoinositolphospholipids in the attachment to the luminal midgut surface of rhodnius prolixus. | trypanosoma cruzi epimastigotes adhere in vivo to the luminal surface of their triatomid vector digestive tract by molecular mechanisms, as yet, unknown. here, we show that the administration of 0.5 microm epimastigote major surface glycoinositolphospholipids (gipls) to the infected bloodmeal inhibits up to 90% parasite infection in rhodnius prolixus. the parasite behavior was investigated in vitro using fragments of the insect midgut. the addition of gipls in concentration as low as 50-100 nm i ... | 2007 | 17306256 |
| environmental determinants of the distribution of chagas disease vectors in south-eastern guatemala. | the associations between the presence of triatomines and environmental variables were studied using correlation analysis and logistic regression models for a sample of villages in the south-eastern provinces of guatemala. information on the presence of triatoma dimidiata, t. nitida and rhodnius prolixus came from entomological surveys carried out by the ministry of health of guatemala as part of its vector control programme. environmental information for each village was extracted from digital t ... | 2007 | 18686245 |
| [using elisa for identifying triatominae feeding behaviour in colombia]. | standardising the elisa technique for identifying triatomine insects' feeding behaviour. | 2007 | 18209827 |
| the biogeography and population genetics of neotropical vector species. | phylogenetic and population genetic data support the pliocene or pleistocene divergences of the co-distributed hematophagous insect vectors, the sand fly lutzomyia longipalpis s.l., the mosquitoes anopheles darlingi and a. albitarsis s.l., and the triatomines rhodnius prolixus and r. robustus. we examined patterns of divergence and distribution in relation to three hypotheses of neotropical diversification: miocene/pliocene marine incursion, pliocene/pleistocene riverine barriers and pleistocene ... | 2007 | 17534382 |
| transepithelial transport of salicylate by the malpighian tubules of insects from different orders. | the organic anion salicylate is a plant secondary metabolite that protects plants against phytophagous insects. in this study, a combination of salicylate-selective microelectrodes and a radioisotope tracer technique was used to study the transepithelial transport of salicylate by the malpighian tubules of 10 species of insects from five orders. our results show that salicylate is transported into the lumen of the malpighian tubules in all the species evaluated, except rhodnius prolixus. the tra ... | 2007 | 17640663 |
| biglutaminyl-biliverdin ix alpha as a heme degradation product in the dengue fever insect-vector aedes aegypti. | hemoglobin digestion in the midgut of hematophagous animals results in the release of its prosthetic group, heme, which is a pro-oxidant molecule. heme enzymatic degradation is a protective mechanism that has been described in several organisms, including plants, bacteria, and mammals. this reaction is catalyzed by heme oxygenase and results in formation of carbon monoxide, ferrous ion, and biliverdin ixalpha. during digestion, a large amount of a green pigment is produced and secreted into the ... | 2007 | 17508725 |
| effect of the n-terminus on heme cavity structure, ligand equilibrium, rate constants, and reduction potentials of nitrophorin 2 from rhodnius prolixus. | the d1a mutant of recombinant np2 has been prepared and shown to have the expression-initiation methionine-0 cleaved during expression in e. coli, as is the case for recombinant np4, where ala is the first amino acid for the recombinant protein as well as for the mature native protein. the heme substituent 1h nmr chemical shifts of np2-d1a and those of its imidazole, n-methylimidazole, and cyanide complexes are rather different from those of np2-m0d1. this difference is likely due to the much sm ... | 2007 | 17506528 |
| tetraethylammonium and nicotine transport by the malpighian tubules of insects. | we examined transepithelial transport of the prototypical type i organic cation (oc) tetraethylammonium (tea) and the plant alkaloid nicotine by the isolated malpighian tubules (mts) of nine insect species from six orders. isolated tubules were exposed to radiolabelled forms of either tea or nicotine in the bathing (basal) fluid. luminal (apical) secreted fluid was collected and tea or nicotine concentration was determined. active net transport of nicotine from bath to lumen was observed by the ... | 2006 | 16527303 |
| trypanosoma cruzi: effects of infection on cathepsin d activity in the midgut of rhodnius prolixus. | cathepsin d activity was estimated in midgut homogenates from rhodnius prolixus, uninfected and experimentally infected with trypanosoma cruzi, at different times after blood ingestion. no enzyme activity was found in the anterior midgut and rectum. in the posterior midgut, enzyme activity was found both in lumen and wall. in starved uninfected insects, in lumen and wall, cathepsin d activity was high, decreasing to a constant rate at 1-15 days after feeding. in insects infected with t. cruzi ca ... | 2006 | 16288741 |
| trypanosoma rangeli: characterization of a mg-dependent ecto atp-diphosphohydrolase activity. | in this work we describe the ability of living trypanosoma rangeli to hydrolyze extracellular atp. in these intact parasites whose viability was assessed before and after the reactions by motility and by trypan blue dye exclusion, there was a low level of atp hydrolysis in the absence of any divalent metal (1.53+/-0.12 nmol p(i)/h x 10(7) cells). the atp hydrolysis was stimulated by mgcl(2) and the mg-dependent ecto-atpase activity was 5.24+/-0.64 nmol p(i)/h x 10(7) cells. the mg-dependent ecto ... | 2006 | 16289087 |
| a micro-spreading improvement for spermatogenic chromosomes from triatominae (hemiptera-reduviidae). | cytogenetics of triatomines have been a valuable biological tool for the study of evolution, taxonomy, and epidemiology of these vectors of trypanosoma cruzi. here we present a single microtube protocol that combines micro-centrifugation and micro-spreading, allowing high quality cytogenetic preparations from male gonadal material of rhodnius prolixus and triatoma lecticularia. the amount of cellular scattering can be modulated, which can be useful if small aggregates of synchronous cells are de ... | 2006 | 16862334 |
| rna interference of the salivary gland nitrophorin 2 in the triatomine bug rhodnius prolixus (hemiptera: reduviidae) by dsrna ingestion or injection. | mass sequencing of cdna libraries from salivary glands of triatomines has resulted in the identification of many novel genes of unknown function. the aim of the present work was to develop a functional rna interference (rnai) technique for rhodnius prolixus, which could be widely used for functional genomics studies in triatomine bugs. to this end, we investigated whether double-stranded rna (dsrna) can inhibit gene expression of r. prolixus salivary nitrophorin 2 (np2) and what impact this migh ... | 2006 | 16935217 |
| could the chagas disease elimination programme in venezuela be compromised by reinvasion of houses by sylvatic rhodnius prolixus bug populations? | the andean pact initiative (1997) committed andean countries to eliminate vectorial transmission of chagas disease by 2010 via widespread residual insecticide spraying. in venezuela, this aim could be compromised by reinvasion of houses by palm tree populations of the major vector rhodnius prolixus. to test this hypothesis, a multivariate logistic regression was undertaken of risk factors for triatomine infestation and colonization in 552 houses and 1068 peri-domestic outbuildings in barinas sta ... | 2006 | 17002733 |
| analysis of antenal sensilla patterns of rhodnius prolixus from colombia and venezuela. | antennal sensilla patterns were used to analyze population variation of domestic rhodnius prolixus from six departments and states representing three biogeographical regions of colombia and venezuela. discriminant analysis of the patterns of mechanoreceptors and of three types of chemoreceptors on the pedicel and flagellar segments showed clear differentiation between r. prolixus populations east and west of the andean cordillera. the distribution of thick and thin-walled trichoids on the second ... | 2006 | 16444424 |
| take-off activity and orientation of triatomines (heteroptera: reduviidae) in relation to the presence of artificial lights. | we analysed the flying activity of triatoma infestans and rhodnius prolixus when confronted to artificial lights of different spectral quality. we found that the presence of light sources (white or ultraviolet) did not affect their spontaneous take-off rate. the comparison between species showed that r. prolixus was more prone to fly than t. infestans. females of t. infestans initiated flight more frequently than males of the same species. although the same tendency was observed in r. prolixus, ... | 2006 | 16460653 |
| parasitogenic alterations of vector behaviour. | in many parasite-vector systems, alterations of the behaviour of the blood-sucking arthropods result in an increase of the transmission rate, but the underlying mechanisms are elucidated in only some systems. the more sluggish movements of the trypanosoma rangeli-infected triatomine rhodnius prolixus might increase the rate of predation by insectivorous mammals but also the transmission rate between the triatomines via cannibalism. alterations of the feeding behaviour by which the number of atta ... | 2006 | 16530007 |
| salivation pattern of rhodnius prolixus (reduviidae; triatominae) in mouse skin. | the objective of this work was to study the pattern of salivation of triatomines during feeding in mouse skin. rhodnius prolixus was fed with a solution of the dye acridine orange or fluorescein. the saliva was efficiently labelled with acridine orange, probably due to the difference in ph between the salivary gland (6.0) and the hemolymph (6.5-7.0). this procedure was not effective at labelling the saliva of triatoma infestans, however, fluorescent labelling of r. prolixus saliva allowed us to ... | 2006 | 16580013 |
| trypanosoma cruzi: experimental parasitism of bone and cartilage. | trypanosoma cruzi causes chagas' disease, a systemic infection that affects cells of meso-, endo-, and ectodermic origin. however, as far as we know, the presence of t. cruzi stages in bone has not been reported previously, and it has scarcely been investigated in cartilage. we inoculated 7- and 20-day-old (8 and 15 g) nmri albino mice i.p. with metacyclic trypomastigotes from rhodnius prolixus used for xenodiagnosis of mice previously infected with mammalian, human, and triatomines isolates, ch ... | 2006 | 16721600 |
| control of chagas disease. | the southern cone initiative (iniciativa de salud del cono sur, incosur) to control domestic transmission of trypanosoma cruzi is a substantial achievement based on the enthusiasm of the scientific community, effective strategies, leadership, and cost-effectiveness. incosur triggered the launch of other regional initiatives in central america and in the andean and amazon regions, which have all made progress. the central american initiative targeted the elimination of an imported triatomine bug ... | 2006 | 16735164 |
| antiserum against perimicrovillar membranes and midgut tissue reduces the development of trypanosoma cruzi in the insect vector, rhodnius prolixus. | antiserum raised against rhodnius prolixus perimicrovillar membranes (pmm) and midgut tissue interfered with the midgut structural organization and reduced the development of trypanosoma cruzi in the r. prolixus insect vector. sds-page and western blot analyses confirmed the specific recognition of midgut proteins by the antibody. feeding, mortality, molt, and oviposition of the insects were unaffected by feeding with the antiserum. however, the eclosion of the eggs were reduced from r. prolixus ... | 2006 | 16759654 |
| cellular immune response in rhodnius prolixus: role of ecdysone in hemocyte phagocytosis. | in this paper we investigate in vivo and in vitro effects of orally administered azadirachtin and ecdysone on the phagocytic responses of rhodnius prolixus 5th-instar larval hemocytes to the yeast saccharomyces cerevisiae. groups of insects fed non-treated blood (control) and insects that received azadirachtin plus ecdysone in the blood meal were inoculated with yeast cells in the hemocele. the injected yeast cells disappeared rapidly from the hemolymph, being removed completely by 90min after i ... | 2006 | 16759667 |
| web 2086, a platelet-activating factor antagonist, inhibits prophenoloxidase-activating system and hemocyte microaggregation reactions induced by trypanosoma rangeli infection in rhodnius prolixus hemolymph. | the effects of the triazolodiazepine web 2086, a platelet-activating factor (paf) antagonist, on hemocyte microaggregation and prophenoloxidase (propo)-activating system in the hemolymph, hemocoelic infection and mortality in fifth-instar larvae of rhodnius prolixus inoculated with trypanosoma rangeli were investigated. hemocoelic injection of short t. rangeli epimastigotes (1x10(4) parasites/insect) in r. prolixus that were previously fed with blood containing 1mum of web 2086 resulted in (i) r ... | 2006 | 16777137 |
| taxonomic study of the phyllosoma complex and other triatomine (insecta: hemiptera: reduviidae) species of epidemiological importance in the transmission of chagas disease: using its-2 and mtcytb sequences. | the purpose of this work was to clarify the taxonomy and phylogenetic relationship of the phyllosoma complex and other important vectors in mexico. the internal transcribed spacer 2 (its-2) of rdna and the cytochrome b gene of mtdna (mtcytb) were analyzed for the following species of triatomine: triatoma bassolsae, t. longipennis, t. mazzottii, t. mexicana, t. pallidipennis, t. picturata, and t. phyllosoma belonging to the phyllosoma complex, as well as t. dimidiata, t. rubida, t. infestans, and ... | 2006 | 16815044 |
| trypanosoma rangeli: effects of physalin b on the immune reactions of the infected larvae of rhodnius prolixus. | physalins are seco-steroids obtained from plants of the family solanaceae. herein, we tested physalis angulata l purified physalin b as an immunomodulatory compound in 5th-instar larvae of rhodnius prolixus, which were systemically infected with the h14 trypanosoma rangeli strain protozoan. in uninfected insects, the effective concentration of physalin b, which inhibited 50% of the blood ingested (ed(50)) volume, was 15.2+/-1.6 microg/ml of the meal. ecdysis processes and mortality in uninfected ... | 2006 | 16271717 |
| 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 |
| 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 |
| aspects of classification of hemiptera hemocytes from six triatomine species. | the objective of this work was to characterize, and compare different morphological types of hemocytes of rhodnius prolixus, rhodnius robustus, rhodnius neglectus, triatoma infestans, panstrongylus megistus, and dipetalogaster maximus. this information provides the basis for studying the cellular immune systems of these insects. seven morphological hemocyte types were identified by phase-contrast microscopy: prohemocytes, plasmatocytes, granular cells, cystocytes, oenocytoids, adipohemocytes and ... | 2006 | 1842390 |
| a heme-degradation pathway in a blood-sucking insect. | hematophagous insects are vectors of diseases that affect hundreds of millions of people worldwide. a common physiological event in the life of these insects is the hydrolysis of host hemoglobin in the digestive tract, leading to a massive release of heme, a known prooxidant molecule. diverse organisms, from bacteria to plants, express the enzyme heme oxygenase, which catalyzes the oxidative degradation of heme to biliverdin (bv) ix, co, and iron. here, we show that the kissing bug rhodnius prol ... | 2006 | 16698925 |
| binding sites for igg-fc in hemocyte adherent cells of hematophagous bugs (rhodnius prolixus). | 2006 | 2152199 | |
| short- and long-term effects of proallatotoxin (ethoxyprecocene ii) on rhodnius prolixus females. | oogenesis and oviposition can be inhibited in female of rhodnius prolixus by means of short-term experiment (first reproductive cycle) of a single dose of ethoxyprecocene ii given by ingestion. the inhibition is dose-dependent as measured by oocyte growth, egg maturation and egg deposition. in a long-term experiment (second and third reproductive cycles) egg production and oogenesis can be partially or totally re-established by subsequent blood meals without ethoxyprecocene ii. these findings su ... | 2006 | 3333534 |
| efficacy of ivermectin against the bloodsucking insect, rhodnius prolixus (hemiptera, triatominae). | ivermectin (0.2 mg/kg body weight) caused a high mortality in nymphs and adults of rhodnius prolixus following a single meal in mice sub-cutaneously injected with the drug. this effect was more evident in nymphs of 1st-and 2nd-instar than in older nymphs and adults. third-instar nymphs presented a high mortality when fed on mice treated with ivermectin 24 and 48 hours previously, while mortality was significantly reduced in nymphs fed on mice treated 72 hours before. surviving 3rd-instar nymphs ... | 2006 | 3915765 |
| [the teratogenic and toxic effect of unsaturated short-chain fatty acids in rhodnius prolixus]. | the teratogenic role of two short-chain unsaturated fatty acids, octinoic acid and undecylenic acid on the hemimetabolic metamorphosis of the insect rhodnius prolixus (hemipter) is studied. the acids penetrate through the cuticle of the abdomen and tarsi, independently of the amount of distention. the effects are registered equally in satiated or hungry insects, in those treated topically or in those where the treatment was applied to the support paper. the acids apparently do not affect the for ... | 2006 | 3915763 |
| [on the mode of oviposition of triatoma megista and rhodnius prolixus]. | 2006 | 13943306 | |
| psychology of learning: a new approach to study behavior of rhodnius prolixus stal under laboratory conditions. | conditioning methodologies associated with the psychology of learning are suggested as a new strategy to investigate behavior of the assassin bug rhodnius prolixus, which is the main vector of chagas disease in venezuela. chagas disease is the fourth leading cause of death in latin america, as it causes severe chronic illness and approximately 43,000 deaths per year. to illustrate this strategy, two preliminary experiments are reported. in the first, pavlovian conditioning was examined by pairin ... | 2005 | 16512287 |
| 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 |
| cathepsin d-mediated yolk protein degradation is blocked by acid phosphatase inhibitors. | vitellin (vt) is a lipoglycophosphoprotein stored inside the eggs of every oviparous organism during oogenesis. in the blood-sucking bug rhodnius prolixus, vt is deposited inside growing oocytes together with two acid hydrolases: acid phosphatase (ap) and cathepsin d (cd). egg fertilization triggers ap activity and vt proteolysis in vivo [insect biochem. mol. biol. 2002 (32) 847]. here, we show that cd is the main protease targeting vt proteolysis during egg development. cd activity in total egg ... | 2005 | 15797237 |
| edysteroid receptor (ecr) shows marked differences in temporal patterns between tissues during larval-adult development in rhodnius prolixus: correlations with haemolymph ecdysteroid titres. | the presence of ecdysteroid receptor (ecr) in various tissues was studied throughout larval-adult development of the blood-sucking bug, rhodnius prolixus, using an antibody to ecr that recognizes all isoforms. on western blots, the antibody recognizes three peptides of approximate molecular masses of 70, 68 and 64 kda, from epidermis and fat body of developing larvae, which contain high levels of haemolymph ecdysteroids. these peptides are absent from both unfed larvae and adults, which are devo ... | 2005 | 15686643 |
| the role of salivary lipocalins in blood feeding by rhodnius prolixus. | in order to overcome host mechanisms that prevent blood loss, the blood-sucking bug rhodnius prolixus has evolved a complex salivary secretion containing dozens of different proteins. a number of these have been characterized and found to have roles in inhibiting various hemostatic or inflammatory systems. interestingly, many of these biologically active salivary proteins belong to the lipocalin protein family. a proliferation of lipocalin genes has occurred via gene duplication and subsequent d ... | 2005 | 15660358 |
| 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 ch ... | 2005 | 15626503 |
| 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 |
| nitric oxide interaction with insect nitrophorins and thoughts on the electron configuration of the {feno}6 complex. | the nitrophorins are no-carrying heme proteins that are found in the saliva of two species of blood-sucking insects, the kissing bug (rhodnius prolixus) and the bedbug (cimex lectularius). in both insects the no is bound to the ferric form of the protein, which gives rise to kds in the micromolar to nanomolar range, and thus upon injection of the saliva into the tissues of the victim the no can dissociate to cause vasodilation and inhibition of platelet aggregation. the structures of the protein ... | 2005 | 15598503 |
| heme-assisted s-nitrosation of a proximal thiolate in a nitric oxide transport protein. | certain bloodsucking insects deliver nitric oxide (no) while feeding, to induce vasodilation and inhibit blood coagulation. we have expressed, characterized, and determined the crystal structure of the cimex lectularius (bedbug) nitrophorin, the protein responsible for no storage and delivery, to understand how the insect successfully handles this reactive molecule. surprisingly, no binds not only to the ferric nitrophorin heme, but it can also be stored as an s-nitroso (sno) conjugate of the pr ... | 2005 | 15637157 |
| molecular characterisation of trypanosoma rangeli strains isolated from rhodnius ecuadoriensis in peru, r. colombiensis in colombia and r. pallescens in panama, supports a co-evolutionary association between parasites and vectors. | we present data on the molecular characterisation of strains of trypanosoma rangeli isolated from naturally infected rhodnius ecuadoriensis in peru, from rhodnius colombiensis, rhodnius pallescens and rhodnius prolixus in colombia, and from rhodnius pallescens in panama. strain characterisation involved a duplex pcr with s35/s36/kp1l primers. mini-exon gene analysis was also carried out using trint-1/trint-2 oligonucleotides. kdna and mini-exon amplification indicated dimorphism within both dna ... | 2005 | 15639744 |
| expression of fluorescent genes in trypanosoma cruzi and trypanosoma rangeli (kinetoplastida: trypanosomatidae): its application to parasite-vector biology. | two trypanosoma cruzi-derived cloning vectors, ptrex-n and pbs:calb1/cub01, were used to drive the expression of green fluorescent protein (gfp) and dsred in trypanosoma rangeli tejera, 1920, and trypanosoma cruzi chagas, 1909, isolates, respectively. regardless of the species, group, or strain, parasites harboring the transfected constructs as either episomes or stable chromosomal integrations showed high-level expression of fluorescent proteins. tagged flagellates of both species were used to ... | 2005 | 15691008 |
| insecticidal effects of canatoxin on the cotton stainer bug dysdercus peruvianus (hemiptera: pyrrhocoridae). | canatoxin (cntx) is a variant form of urease isolated from canavalia ensiformis (leguminosaea) seeds. a possible role in the plant defense was proposed for cntx, due to its toxicity upon feeding to the beetle callosobruchus maculatus, and the hematophagous bug, rhodnius prolixus. the toxic effect is caused by a canatoxin-derived peptide ( approximately 10kda) formed by insect cathepsin-like digestive enzymes. in order to evaluate their potential as bioinsecticides, the effects of cntx and its pe ... | 2005 | 15804524 |
| geographical characterization of the triatomine infestations in north-central guatemala. | in an entomological study in 2002, the degree of domestic and peridomestic infestation with triatomine bugs and the geographical distribution of such infestations were investigated in north-central guatemala. the survey team searched for triatomines in houses constructed with mud walls or thatched roofs, in villages suspected of being infested. the level of infestation observed was lower than that seen in the same area and in eastern guatemala, in a preliminary survey, 3 years earlier. most of t ... | 2005 | 15829138 |
| structural determinants of factor ix(a) binding in nitrophorin 2, a lipocalin inhibitor of the intrinsic coagulation pathway. | nitrophorin 2 (np2) is a salivary lipocalin from rhodnius prolixus that binds with coagulation factors ix (fix) and ixa (fixa). binding of np2 with fixa results in potent inhibition of the intrinsic factor xase complex. a panel of site-directed surface mutants of np2 was generated to locate determinants of high affinity fix(a) binding. the locations of the mutations were based on comparisons with the related, but less potent, inhibitor nitrophorin 3 (np3). three point mutants (k21a, k92a, and v9 ... | 2005 | 15866866 |
| biological effect of 1-dodecanol in teneral and post-teneral rhodnius prolixus and triatoma infestans (hemiptera: reduviidae). | topical application of 1-dodecanol was significantly more toxic against teneral first nymphs (1-3 h old) than post-teneral first nymphs (24 h old). the lethal dose ratios were 711,500 for rhodnius prolixus and 3613 for triatoma infestans. no significative difference between ld50 was found when 1-dodecanol was injected in recently hatched adult r. prolixus (1-4 h old) nor in older adults (24 h old). these values were similar to those calculated for deltamethrin (an effective triatomicide), showin ... | 2005 | 15867966 |
| identifying health centers in honduras infested with rhodnius prolixus using the seroprevalence of chagas disease in children younger than 13 years. | the objective of this study is to determine if a chagas disease protocol starting with a serological survey is as reliable at identifying insect-infested areas as one using the gold standard entomological survey. the study found that health center areas infested with rhodnius prolixus were identified using a threshold seroprevalence of 0.1%. the serological survey took half the time and was 30% less expensive than the entomological survey. developing countries with limited resources may find thi ... | 2005 | 16103595 |
| towards an understanding of the interactions of trypanosoma cruzi and trypanosoma rangeli within the reduviid insect host rhodnius prolixus. | this review outlines aspects on the developmental stages of trypanosoma cruzi and trypanosoma rangeli in the invertebrate host, rhodnius prolixus. special attention is given to the interactions of these parasites with gut and hemolymph molecules and the effects of the organization of midgut epithelial cells on the parasite development. the vector insect's permissiveness to t. cruzi, which develops in the vector gut, largely depends on the host nutritional state, the parasite strain and the molec ... | 2005 | 16127548 |
| trypanosoma rangeli interactions within the vector rhodnius prolixus: a mini review. | this article is an integrative mini review of the research on the interactions between trypanosoma rangeli and the insect vector, rhodnius prolixus. special attention is given to the interactions of these parasites with the gut environment, gut walls, with hemolymph invasion, hemocytes, hemocyte microaggregations, prophenoloxidase-activating system, superoxide, and nitric acid generation and eicosanoid pathways. we described factors affecting vectorial capacity and suggested that t. rangeli may ... | 2005 | 16184237 |
| structural and morphological characterization of hemozoin produced by schistosoma mansoni and rhodnius prolixus. | hemozoin (hz) is a heme crystal produced upon the digestion of hemoglobin (hb) by blood-feeding organisms as a main mechanism of heme disposal. the structure of hz consists of heme dimers bound by reciprocal iron-carboxylate interactions and stabilized by hydrogen bonds. we have recently described heme crystals in the blood fluke, schistosoma mansoni, and in the kissing bug, rhodnius prolixus. here, we characterized the structures and morphologies of the heme crystals from those two organisms an ... | 2005 | 16229843 |
| [triatomines (reduviidae: triatominae) in a chagas disease focus in talaigua nuevo (bolívar, colombia)]. | the epidemiological importance and ecological characteristics of triatomines were investigated in a chagas disease focus in talaigua nuevo, bolivar province. | 2005 | 16433183 |
| presence and activity of a dippu-dh31-like peptide in the blood-feeding bug, rhodnius prolixus. | the blood-feeding bug, rhodnius prolixus, ingests large blood meals, then undergoes a period of rapid diuresis which is under neurohormonal control. in both cockroach (diploptera punctata) and fruit fly (drosophila melanogaster) a calcitonin-like dh31 neuropeptide has been identified [coast gm, webster sg, schegg km, tobe ss, schooley da. the drosophila melanogaster homologue of an insect calcitonin-like diuretic peptide stimulates v-atpase activity in fruit fly malpighian tubules. j exp biol 20 ... | 2005 | 15626502 |
| a new model for proton pumping in animal cells: the role of pyrophosphate. | the h+-ppase activity was characterized in membrane fractions of ovary and eggs of rhodnius prolixus. this activity is totally dependent on mg2+, independent of k+ and strongly inhibited by naf, idp and ca2+. the membrane proteins of eggs were analyzed by western blot using antibodies to the h+-ppase from arabidopsis thaliana. the immunostain was associated with a single 65-kda polypeptide. this polypeptide was immunolocalized in yolk granule membranes by optical and transmission electron micros ... | 2004 | 14723894 |
| [defecation index and reproductive success of triatoma maculata (hemiptera: reduviidae) under laboratory conditions]. | the reproductive and defecating behavior of triatoma maculata (erichson 1848) was studied on animals from an university culture in venezuela. this species does not reach the importance of rhodnius prolixus stal 1859 as chagas disease vector in venezuela. this study addressed the role of defecating frequency, an index of how dangerous the animals are for the human population, and its relationship with why t. maculata is a less important vector than r. prolixus. human blood was fed to the insects ... | 2004 | 17354403 |
| changes in fine structure of the ventral intersegmental abdominal muscles in the adult of rhodnius prolixus. | in rhodnius prolixus, after the imaginal molt, the intersegmental muscles completely lose their contractile material, and are transformed into thin strands containing nuclei. it is possible that these muscular strands are finally pinched off as mononucleated myoblasts. these residual muscles apparently maintain a normal innervation--which persists to the end of the imago's life. moreover, they appear to show some aspects of synthetic activity after the adult has been fed: in this case, there is ... | 2004 | 524342 |
| effect of blood components, abdominal distension, and ecdysone therapy on the ultrastructural organization of posterior midgut epithelial cells and perimicrovillar membranes in rhodnius prolixus. | the effects of blood components, nerve-cord severance, and ecdysone therapy on the posterior midgut epithelial cells of 5th-instar rhodnius prolixus nymphs 10 days after feeding were analyzed by transmission electron microscopy. cutting the nerve-cord of the blood-fed insects partially reduced the development of microvilli and perimicrovillar membranes (pmm), and produced large vacuoles and small electrondense granules; insects fed on ringer's saline diet exhibited well developed microvilli and ... | 2004 | 15761596 |
| effects of eicosanoid biosynthesis inhibitors on the prophenoloxidase-activating system and microaggregation reactions in the hemolymph of rhodnius prolixus infected with trypanosoma rangeli. | investigations on the effects of eicosanoid biosynthesis inhibitors on the hemocyte microaggregation and prophenoloxidase (propo)-activating system in the hemolymph, parasitemia and mortality of rhodnius prolixus infected with trypanosoma rangeli were performed. hemocoelic injection of live t. rangeli epimastigotes into fifth-instar larvae of r. prolixus that previously fed on blood containing an inhibitor of phospholipase a(2) (dexamethasone), a specific inhibitor of the cyclooxygenase pathway ... | 2004 | 15019517 |
| changes associated with laboratory rearing in antennal sensilla patterns of triatoma infestans, rhodnius prolixus, and rhodnius pallescens (hemiptera, reduviidae, triatominae). | we examined changes in the array of antennal sensilla of three species of triatominae (triatoma infestans, rhodnius prolixus, and r. pallescens) following their establishment for different periods in laboratory culture. in each case, the laboratory colonies were compared with conspecific samples taken directly from the field, by quantitative analysis of the sensilla arrays on the three distal segments of the antenna in terms of the densities of three types of chemoreceptors (basiconics and thick ... | 2004 | 15057343 |
| inhibition of hemocyte microaggregation reactions in rhodnius prolixus larvae orally infected with trypanosoma rangeli. | hemocoelic inoculation of epimastigotes of trypanosoma rangeli strain h14 into 5th-instar larvae of rhodnius prolixus previously fed on blood containing the same parasites, showed reduced number of hemocyte microaggregates in the hemolymph, enhanced number of flagellates in the hemolymph as well as increased mortality of these insects. all these effects were counteracted by combined inoculation of r. prolixus with t. rangeli and arachidonic acid. in vitro assays using hemolymph taken from insect ... | 2004 | 15208035 |
| isolation of serratia marcescens in the midgut of rhodnius prolixus: impact on the establishment of the parasite trypanosoma cruzi in the vector. | the effects of resident bacteria in the stomach of 5th-instar larvae of rhodnius prolixus on the erythrocyte lysis and trypanosoma cruzi infection were studied. the bacteria population increased approximately 10,000-fold after feeding. hemolysis rose to approximately 28% within 24h postfeeding and then linearly grew until day 4 attaining almost 100%. the number of surviving y strain of t. cruzi in the stomach declined drastically, while the infection with dm28c clone was maintained stable. five ... | 2004 | 15208042 |
| lignoids in insects: chemical probes for the study of ecdysis, excretion and trypanosoma cruzi-triatomine interactions. | the effects of phytochemicals (lignans and neolignans) are reviewed in a variety of insect species with special focus on the recent advances on feeding, excretion and trypanosoma cruzi interactions with rhodnius prolixus. burchellin, podophyllotoxin, pinoresinol, sesamin, licarin a, and nordihydroguaiaretic acid (ndga) added to the diet of rhodnius prolixus larvae induce antifeedant effects only in doses up to 100 microg/ml of blood meal. additionally, pinoresinol and ndga significantly inhibit ... | 2004 | 15302525 |
| mortality profiles of rhodnius prolixus (heteroptera: reduviidae), vector of chagas disease. | life table data of rhodnius prolixus (heteroptera: reduviidae) kept at laboratory conditions were analysed in search for mortality patterns. gompertz and weibull mortality models seem adequate to explain the sigmoid shape of the survivorship curve. a significant fit was obtained with both models for females (r(2) = 0.70, p < 0.0005 for the gompertz model; r(2) = 0.78, p < 0.0005 for the weibull model) and for males (r(2) = 0.39, p < 0.0005 for the gompertz model; r(2) = 0.48, p < 0.0005 for the ... | 2004 | 15350863 |
| chlorinated tyrosine derivatives in insect cuticle. | a method for quantitative measurement of 3-monochlorotyrosine and 3,5-dichlorotyrosine in insect cuticles is described, and it is used for determination of their distribution in various cuticular regions in nymphs and adults of the desert locust, schistocerca gregaria. the two chlorinated tyrosine derivatives were present in all analyzed regions in mature adult locusts, the highest concentrations were found in the sclerotized cuticle of femur and tibia, but significant amounts were also present ... | 2004 | 15475302 |
| mixed domestic infestation by rhodnius prolixus stal, 1859 and panstrongylus geniculatus latreille, 1811, vector incrimination, and seroprevalence for trypanosoma cruzi among inhabitants in el guamito, lara state, venezuela. | mixed infestation of nymphs and adults of rhodnius prolixus stal, 1859 and panstrongylus geniculatus latreille, 1811 was detected in 3 (15%) of 20 dwellings in el guamito, an endemic focus of chagas disease in lara state, venezuela. in one of the houses, both species were positive for trypanosoma cruzi: 14.3% (r. prolixus) and 20% (p. geniculatus ). the overall infection rate in 143 of 352 r. prolixus was 16.1%. parasites isolated from r. prolixus were identified as t. cruzi i by random amplifie ... | 2004 | 15516649 |
| sulfated glycosaminoglycans in two hematophagous arthropod vectors of chagas disease, triatoma brasiliensis and rhodnius prolixus (hemiptera: reduviidae). | the characterization of sulfated glycosaminoglycans (gags) in hematophagous arthropod vectors in general has been limited, with the exception of the studies in the triatomine rhodnius prolixus. heparan sulfate (hs) and chondroitin sulfate (cs) were previously identified and structurally characterized in extracts of whole bodies of fourth instar larvae of r. prolixus. recently, we showed the expression of these two sulfated gags in specific body tissues of adult males and females and in embryos o ... | 2004 | 15581795 |
| antihemostatic strategies of blood-feeding arthropods. | arthropods in at least 23 different families or orders, distributed between two classes (insecta and arachnida), feed on vertebrate blood. they are able to do this despite constraints imposed by a sophisticated array of hemostatic defenses, due to the presence of a wide range of antihemostatic molecules in their saliva, including vasodilators, antiplatelet factors, and anticoagulants. vasodilators include amines, prostaglandins, peptides, proteins, and even a mechanism to store large amounts of ... | 2004 | 15578959 |
| protein functional cycle viewed at atomic resolution: conformational change and mobility in nitrophorin 4 as a function of ph and no binding. | the blood-sucking insect rhodnius prolixus uses nitrophorin 4, a heme protein, to deliver nitric oxide (no) to a victim, causing vasodilation and improved feeding. binding of no occurs at a ferric heme and is modulated by ph. no binding at lower ph induces a large conformational change involving loops a-b and g-h that leads to distal pocket desolvation and protection of the nitrosyl heme complex. we have determined the crystal structures of rhodnius nitrophorin 4 to ultrahigh resolution in four ... | 2004 | 15504026 |
| appetence behaviours of the triatomine bug rhodnius prolixus on a servosphere in response to the host metabolites carbon dioxide and ammonia. | a combination of 1,000 ppm co(2) plus 30-40 ppb nh(3) in an air stream induced rhodnius prolixus nymphs walking on a servosphere to perform a series of appetence behaviours. shortly after the onset of stimulation the nymphs turned sharply upwind towards the source of the chemostimuli (within 13 +/- 9 s) from mostly downwind and crosswind walks in the air stream alone. the mean vector angles of these upwind tracks were concentrated in a cone 60 degrees either side of due upwind. the upwind walkin ... | 2004 | 15503053 |
| rhodnius prolixus malpighian tubule's aquaporin expression is modulated by 5-hydroxytryptamine. | the purpose of the present study was to detect the presence of an aquaporin-like water channel, a member of the major intrinsic protein (mip) family, in the malpighian tubule (mt) of the hematophagous insect rhodnius prolixus, which excrete a large bulk of fluid after a massive blood meal, and its possible regulation by 5-hydroxytryptamine (5-ht). reverse transcription polymerase chain reaction (rt-pcr) and southern blots of cdna was obtained from adult r. prolixus mt poly (a)+ rna. employing de ... | 2004 | 15484262 |
| na+ competes with k+ in bumetanide-sensitive transport by malpighian tubules of rhodnius prolixus. | we examined the effects of bathing saline na+/k+ ratio, bumetanide and hydrochlorothiazide on fluid and ion transport by serotonin-stimulated malpighian tubules of rhodnius prolixus. previous pharmacological and electrophysiological studies indicate that a bumetanide-sensitive na+/k+/2cl- cotransporter is the primary route for basolateral ion entry into the cell during fluid secretion. the goal of this study was to resolve the apparent conflict between relatively high secretion rates by tubules ... | 2004 | 15371478 |
| characterization of an ecto-phosphatase activity in malpighian tubules of hematophagous bug rhodnius prolixus. | we have characterized a phosphatase activity present on the external surface of intact malpighian tubules in rhodnius prolixus. this phosphatase hydrolyses the substrate p-nitrophenyl phosphate at a rate of 3.38 +/- 0.07 nmol pi x mg(-1) x min(-1). phosphatase activity decreased with the increase of the ph from 6.4 to 7.6 ph, a range in which tubules cellular integrity was maintained for at least 1 h. classical inhibitors of acid phosphatase, such as ammonium molybdate, fluoride, vanadate, mpv-p ... | 2004 | 15352154 |
| structural dynamics controls nitric oxide affinity in nitrophorin 4. | nitrophorin 4 (np4) is one of seven nitric oxide (no) transporting proteins in the blood-sucking insect rhodnius prolixus. in its physiological function, no binds to a ferric iron centered in a highly ruffled heme plane. carbon monoxide (co) also binds after reduction of the heme iron. here we have used fourier transform infrared spectroscopy at cryogenic temperatures to study co and no binding and migration in np4, complemented by x-ray cryo-crystallography on xenon-containing np4 crystals to i ... | 2004 | 15258143 |
| extracellular h+ dynamics during oogenesis in rhodnius prolixus ovarioles. | the spatiotemporal dynamics of transmembrane hydrogen ion (h+) fluxes during oogenesis were investigated in the telotrophic ovarioles of the insect, rhodnius prolixus. although rhodnius ovarioles possess exaggerated morphological and electrical polarity between nurse cells and oocytes, little is known about h+ changes during oogenesis, despite the regulatory role played by h+ and ph in many relevant cellular processes. a number of dynamic extracellular h+ fluxes were measured along rhodnius ovar ... | 2004 | 15235012 |
| role of binding site loops in controlling nitric oxide release: structure and kinetics of mutant forms of nitrophorin 4. | nitrophorins are ferric heme proteins that transport nitric oxide (no) from blood-sucking insects to victims. no binding is tighter at lower ph values, as found in the insect salivary gland, and weaker at the ph of the victim's tissue, facilitating no release and subsequent vasodilation. previous structural analyses of nitrophorin 4 (np4) from rhodnius prolixus revealed a substantial no-induced conformational change involving the a-b and g-h loops, which rearrange to desolvate the distal pocket ... | 2004 | 15157102 |
| exploring the sialome of the blood-sucking bug rhodnius prolixus. | rhodnius prolixus is a hemiptera that feeds exclusively on vertebrate blood in all life stages. its salivary glands produce potent pharmacological substances that counteract host hemostasis, including anti-clotting, anti-platelet, and vasodilatory substances. to obtain a further insight into the salivary biochemical and pharmacological complexity of this insect, a cdna library was randomly sequenced, and salivary gland homogenates were fractionated by hplc to obtain aminoterminal sequences of ab ... | 2004 | 14976983 |
| identification and tissue-specific distribution of sulfated glycosaminoglycans in the blood-sucking bug rhodnius prolixus (linnaeus). | we have previously characterized heparan sulfate (hs) as the major ovarian sulfated glycosaminoglycan (gag) in females of rhodnius prolixus, while chondroitin sulfate (cs) was the minor component. using histochemical procedures we found that gags were concentrated in the ovarian tissue but not found inside the oocytes. here, we extend our initial observations of gag expression in r. prolixus by characterizing these molecules in other organs: the fat body, intestinal tract, and the reproductive t ... | 2004 | 14871621 |
| a model for fluid secretion in rhodnius upper malpighian tubules (umt). | we have measured fluid secretion rate in rhodnius prolixus upper malpighian tubules (umt) stimulated to secrete with 5-oh-tryptamine. we used double perfusions in order to have access separately to the basolateral and to the apical cell membranes. thirteen pharmacological agents were applied: ouabain, bafilomycin a(1), furosemide, bumetanide, dioa, probenecid, sits, acetazolamide, amiloride, dpc, bacl(2), pcmbs and dtt. these agents are known to block different ion transport functions, namely at ... | 2004 | 15702374 |
| axial ligand complexes of the rhodnius nitrophorins: reduction potentials, binding constants, epr spectra, and structures of the 4-iodopyrazole and imidazole complexes of np4. | previously, we utilized 4-iodopyrazole (4ipzh) as a heavy atom derivative for the initial solution of the crystal structure of the nitrophorin from rhodnius prolixus, np1, where it was found to bind to the heme with the iodo group disordered in two positions. we have now determined the structure of the 4ipzh complex of np4 at ph 7.5 and find that the geometry and bond lengths at the iron center are extremely similar to those of the imidazole (imh) complex of the same protein (structure determine ... | 2004 | 14673714 |
| temperature preference in rhodnius prolixus, effects and possible consequences. | the present work examines the thermal preference of adult rhodnius prolixus along a temperature gradient. the mean preferred temperature differed slightly between sexes: 25.0 degrees c for males versus 25.4 degrees c for females. this preference was not constant, but varied daily by about 0.2 degrees c for both sexes, and reached its highest value at the onset of the dark phase and was lowest during the light phase. a change in the preferred temperature with the level of starvation was also obse ... | 2004 | 14739030 |
| isolation and characterization of a novel insect defensin from rhodnius prolixus, a vector of chagas disease. | an antimicrobial peptide belonging to the defensin family of small cationic peptides associated with innate immunity in insects was isolated from the hemolymph of rhodnius prolixus, a vector of chagas disease. this peptide, designated r. prolixus defensin a, was purified and sequenced. the active peptide contains 43 residues and aligns well with other insect defensins. however the pre-pro region of the sequence has little shared identity with other insect defensins. we have identified 3 isoforms ... | 2003 | 12650692 |
| a miniature radioimmunoassay for melatonin for use with small samples from invertebrates. | melatonin has been identified in a number of invertebrates, but little is known of its functions or its circadian control. studies in this area are hindered by the lack of an assay for melatonin that is appropriate for use with the small sample volumes obtainable from most invertebrates and with the large numbers of sequential samples generated by circadian studies. we describe and validate a novel, miniature radioimmunoassay (ria) protocol for these purposes. sample volumes of c.50 microl were ... | 2003 | 14511991 |
| inhibition of the sapk/jnk pathway blocks the stimulatory effects of glutamine on fluid secretion by the malpighian tubules of rhodnius prolixus. | physiological levels of amino acids such as glutamine, glutamate, aspartate and proline increase the rates of fluid secretion and ion transport by serotonin-stimulated malpighian tubules (mts) of rhodnius prolixus. here, we examine the proposal that the effects of glutamine are mediated through activation of specific kinases to produce the observed increases in fluid secretion. the glutamine-dependent increase in mt fluid secretion rate was blocked by two chemically unrelated inhibitors of the s ... | 2003 | 14511822 |
| changes in salivary nitrophorin profile during the life cycle of the blood-sucking bug rhodnius prolixus. | the insect rhodnius prolixus is a hematophagous hemipteran that has five nymphal instars. fifth instar nymphs contain, in their salivary glands, four nitrophorins which have already been described in the literature (np1, np2, np3 and np4). two new hemeproteins were isolated and partially characterized from first instar nymphs. np2, that shows an anticoagulant activity, was also identified, but np1, np3 and np4 were not found. as these new hemeproteins have amino-terminal sequences clearly homolo ... | 2003 | 12459197 |