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haemolymph and fat body metallo-protease associated with enterobacter cloacae infection in the bloodsucking insect, rhodnius prolixus.analysis of zymograms with sds-polyacrilamide gel electrophoresis containing gelatin as substrate, and performed on samples of haemolymph or fat body taken from rhodnius prolixus inoculated or not with enterobacter cloacae, demonstrated distinct patterns of protease activities: (i) in the haemolymph two proteases were induced in insects inoculated with bacteria; (ii) two proteases were detected in the fat bodies derived from non-inoculated controls or insect inoculated with sterile culture mediu ...19989921310
yeast culture volatiles as attractants for rhodnius prolixus: electroantennogram responses and captures in yeast-baited traps.responses to air currents carrying volatiles from yeast cultures were measured by means of electroantennograms (eags) in the haematophagous bug rhodnius prolixus and we tested yeast-baited traps in the laboratory. the volatiles liberated by yeast cultures generated a clear electrophysiological response, much higher than that obtained during stimulation with clean air. the addition of yeast cultures to the traps dramatically increased overnight capture. a modification performed on the traps was e ...19999924967
neolignans inhibit trypanosoma cruzi infection of its triatomine insect vector, rhodnius prolixus.two neolignans, burchellin and nordihydroguaiaretic acid (ndga), were toxic only to trypanosoma cruzi clone dm28c maintained in brain heart infusion (bhi) medium at a concentration of 100 microg/ml, not 10 microg/ml. when rhodnius prolixus was fed with epimastigotes of t. cruzi and treated simultaneously with a single dose of burchellin or ndga at 10 pg/ml of blood meal the number of parasites in the gut decreased. whereas burchellin was only partially active, ndga drastically reduced the number ...19999951960
studies on a haemolymph lectin isolated from rhodnius prolixus and its interaction with trypanosoma rangeli.we demonstrated that in rhodnius prolixus haemocyte monolayers, both trypanosoma cruzi and trypanosoma rangeli are capable of inducing haemocyte/parasite clump formation. we also purified, by one-step affinity chromatography, a haemolymph galactoside-binding lectin from r. prolixus which we believe could play an important role in the development of t. rangeli in the haemocoel of the insect vector. this lectin markedly enhanced the activation of clump formation by t. rangeli in r. prolixus haemoc ...199910092472
invertebrate compounds acting on the hemostatic mechanism.physiological secretions from some invertebrates have toxic effects on mammalian blood coagulation and fibrinolytic systems. some of these effects occur because the substances contained in the secretions resemble the components of the hemostatic system. some of the substances have been characterized, and have been found to have similar molecular weights or sequences, which may indicate a common ancestry. the components can be divided into five groups: antithrombic agents (group i); inhibitors an ...199910192653
species specific detection of trypanosoma cruzi and trypanosoma rangeli in vector and mammalian hosts by polymerase chain reaction amplification of kinetoplast minicircle dna.several groups have recently developed molecular tests for the detection of trypanosoma cruzi, the causative agent of chagas' disease. polymerase chain reaction (pcr) amplification of kinetoplast minicircle dna sequences appears to be the most sensitive method. however, the specificity of pcr-based diagnostic methods was challenged when the complete sequence of trypanosoma rangeli dna minicircles was discovered. in the present study, we conducted. pcr experiments using the s35/s36 primers in rho ...199910206119
rhodnius prolixus infected with trypanosoma rangeli: in vivo and in vitro experiments.studies were carried out on the activation of the prophenoloxidase (propo) in adults of rhodnius prolixus infected by short and long epimastigote forms of trypanosoma rangeli. the in vitro activation of the propo cascade using l-dopa as substrate was very low in the absence of fat body extract, hemolymph, and parasites. on the other hand, a higher po activity was observed when short, but not long, epimastigotes of t. rangeli were incubated with fresh hemolymph, fat body extract, and l-dopa. supe ...199910222183
bednet impregnation for chagas disease control: a new perspective.to determine the efficacy and acceptability of deltamethrin-impregnated bednets in controlling chagas disease in south america.199910223214
modulation of murine lymphocyte responsiveness by the saliva of rhodnius prolixus (hemiptera: reduviidae).incorporation of 3h-thymidine by splenic lymphocytes was studied in cba mice that were bitten by the triatomine bug rhodnius prolixus (stål) 14, 7, 4, and 2 d before lymphocyte isolation, respectively. in bitten mice, both spontaneous and mitogen-induced proliferative responses were reduced. the most pronounced effect was observed 4 d after exposure when lymphocytes were significantly suppressed in proliferative response to the mitogens concanavalin a, phytohemagglutinin, and bacterial lipopolys ...199910337105
utility of the polymerase chain reaction in detection of trypanosoma cruzi in guatemalan chagas' disease vectors.for effective control programs, accurate assessment of trypanosoma cruzi infection in vectors is essential and has traditionally been performed by microscopic examination. for particular vectors and not others, polymerase chain reaction (pcr) analysis of fecal samples recently has been shown to be an effective means of detection. the sensitivities of the pcr and microscopy for detection of t. cruzi in different anatomic sites were compared in the two major vectors of guatemala, triatoma dimidiat ...199910344645
development of rhodnius prolixus (hemiptera: reduviidae) under constant and cyclic conditions of temperature and humidity.development of rhodnius prolixus after eclosion until the adult stage was studied at constant temperatures (t), 15, 20, 25, 28, 35 c, and relative humidities (rh), 75, 86 and 97%, and fluctuating (16/8 hr) temperatures, t i/ii, 15/28 c, 20/25 c, 25/28 c and 25/35 c, and relative humidities, rh i/ii, 86/75% and 97/75%. eclosion or molting were not observed at 15 c and 86 or 97% rh, respectively. at 35 c and 75% rh only few insects molted. by alternating t i/ii, 15/28 c and 25/35 c, insects develo ...199910348991
influence of brain and azadirachtin on trypanosoma cruzi development in the vector, rhodnius prolixus.studies on the effects of decapitation, head transplantation, azadirachtin, and ecdysone therapy on the ultrastructural organization of the midgut of rhodnius prolixus, a vector of the protozoan trypanosoma cruzi, show a distinct effect on the organization of the epithelial cells. when insects are decapitated or treated with azadirachtin, the ultrastructural organiza tion of these compartments changed significantly and drastically blocked the development of t. cruzi infection. in converse experi ...199910366535
a missing metabolic pathway in the cattle tick boophilus microplus.heme proteins are involved in a wide variety of biological reactions, including respiration, oxygen transport and oxygen metabolism [1]. the heme prosthetic group is synthesized in almost all living organisms except for a few pathogenic bacteria and trypanosomatids that use blood as food [2] [3]. there is a general belief that all nucleated animal cells synthesize heme [1] [4]. however, blood-feeding arthropods ingest enormous amounts of vertebrate blood in a single meal and the heme pathway has ...199910395540
mitochondrial dna sequence variation among triatomine vectors of chagas' disease.kissing bugs or triatomines (reduviidae: triatominae) are vectors of the chagas' disease agent trypanosoma cruzi. there is a current need for more sensitive tools for use in discrimination of different bug populations and species, thus allowing a better understanding of these insects as it relates to disease transmission and control. in a preliminary analysis of the mitochondrial large subunit ribosomal rna (mtlsurrna) and cytochrome b (mtcytb) genes, we used dna sequencing to study species iden ...199910466963
expression of a functional antibody fragment in the gut of rhodnius prolixus via transgenic bacterial symbiont rhodococcus rhodnii.expression within insects of foreign antiparasitic gene products via microbial symbionts could be used to prevent transmission of vector-borne pathogens to vertebrate hosts. genetically transformed symbiotic bacteria rhodococcus rhodnii expressed functional antibody fragments (rdb3 encoding murine v(h)/k which binds progesterone) that were exported into the gut lumen of the triatomine bug rhodnius prolixus (hemiptera: reduviidae), a vector of chagas disease. transgenic symbionts were maintained ...199910484156
effects of recombinant nitrophorin-2 nitric oxide complex on vascular smooth muscle.nitrophorin-2, isolated from the salivary gland of the blood-sucking insect rhodnius prolixus, is a nitric oxide (no) binding protein. we investigated the effects of recombinant nitrophorin-2 no complex on vascular smooth muscle. the course of relaxation was relative to released no from recombinant nitrophorin-2 no complex. our data suggested nitrophorin-2 was tightly adhesive to the membranes to transport no into the cell during the insect sting.199910501007
dipetalogastin, a potent thrombin inhibitor from the blood-sucking insect. dipetalogaster maximus cdna cloning, expression and characterization.a cdna coding for the thrombin inhibitor dipetalogastin has been isolated from a stomach library of dipetalogaster maximus, a blood-sucking insect. the open reading frame of the cloned inhibitor cdna codes for a protein of 344 amino-acid residues. sequence analysis reveals the existence of three repeated homologous main regions, indicating that the inhibitor consists of three domains. each domain shows a double-headed structure with an internal sequence homology like rhodniin, the thrombin inhib ...199910561601
metalloproteases in trypanosoma rangeli-infected rhodnius prolixus.protease activities in the haemolymph and fat body in a bloodsucking insect, rhodnius prolixus, infected with trypanosoma rangeli, were investigated. after sds-polyacrylamide gel electrophoresis containing gelatin as substrate, analysis of zymograms performed on samples of different tissues of controls and insects inoculated or orally infected with short or long epimastigotes of t. rangeli, demonstrated distinct patterns of protease activities: (i) proteases were detected in the haemolymph of in ...199910585653
inter-specific and developmental differences on the array of antennal chemoreceptors in four species of triatominae (hemiptera: reduviidae).the aim of the work was to investigate the pattern of chemoreceptor sensilla in adults and fifth stage nymphs of rhodnius prolixus, r. neglectus, triatoma infestans and t. sordida in order to study differences and similarities between genera and species. three types of sensilla were analyzed by light microscopy: thin-walled trichoidea, thick-walled trichoidea and basiconica. the number of sensilla of each three types were counted. the length of the antennal segments were also used as a variable ...200010656707
haematophagy and cleptohaematophagy of clerada apicicornis (hemiptera: lygaeidae), a potential biological control agent of rhodnius prolixus (hemiptera: reduviidae).because of its ability to prey on triatominae in rural houses, clerada apicicornis has been suggested as a potential biological control agent of rhodnius prolixus. it has also been suggested as a potential vector of mammalian trypanosomes such as trypanosoma cruzi, because of its ability to take blood directly from mammals. to help resolve these conflicting ideas, we assessed the haematophagic behaviour of c. apicicornis by carrying out feeding trials on laboratory animals. cleptohaematophagic b ...200010656719
[towards the elimination of the transmission of trypanosoma cruzi in honduras and central american countries].central america is composed of seven countries: belice, costa rica, el salvador, guatemala, honduras, nicaragua and panama. chagas disease exists in all seven countries, but with major prevalence in el salvador, guatemala, honduras and nicaragua. the main species of triatomine vectors are: rhodnius prolixus, triatoma dimidiata y rhodnius pallescens. in 1997 the central american countries launched an initiative for the vectorial and transfusion transmission control of chagas disease. the objectiv ...199910668252
biological factors involving trypanosoma cruzi life cycle in the invertebrate vector, rhodnius prolixus. 199910677719
immunity in rhodnius prolixus: trypanosomatid-vector interactions. 199910677721
dependence of the entomopathogenic fungus, beauveria bassiana, on high humidity for infection of rhodnius prolixus.the impact of relative humidity (rh) on the infective potential of the isolate bb inra 297 of beauveria bassiana (bals.) vuillemin (deuteromycotina: hyphomycetes) against first instar nymphs of rhodnius prolixus stål. (hemiptera: reduviidae) was determined. fungus-treated insects were exposed to rhs ranged from 75 to 100% at 25 degrees c. results clearly showed a threshold of humidity at ca. 96% for high and rapid mortality. after initial exposure to increasing periods of 97% (4, 8, 16, 24, 36 a ...199910721518
the ability of rhodnius prolixus (hemiptera; reduviidae) to approach a thermal source solely by its infrared radiation.the ability of the haematophagous bug rhodnius prolixus to approach a pure ir source only by its long-wave infrared radiation (ir) was investigated. to exclude any heated air from reaching the bug a cooled ir-transmitting window was placed between the ir-source (a peltierelement heated to 35 degrees c) and the bug. starved bugs were tested under invisible short-wave ir illumination (lambda<1 µm) in order to exclude also any visual cues. the number of bugs approaching the ir-source was significan ...200010742523
effects of fluctuating moisture and temperature regimes on the infection potential of beauveria bassiana for rhodnius prolixus.the effect of both moisture and temperature on the infective potential of beauveria bassiana to the chagas' disease vector, rhodnius prolixus, was studied under fluctuating regimes. at constant 25 degrees c, contaminated first-instar nymphs exposed to increasing daily periods of initial exposure to 97% rh, followed by transfer to reduced humidity (43, 53, 75, and 86% rh), showed a significant reduction in mortality when the 97% rh exposure time declined from 12 to 8 h per day. the duration of di ...200010753596
distribution of domestic triatominae and stratification of chagas disease transmission in oaxaca, mexico.mexico has 18 species of triatomine bugs (hemiptera: reduviidae) reported to be vectors of trypanosoma cruzi. chagas disease is widespread in mexico, with up to 3.5% seropositivity of human transfusion blood. the state of oaxaca has the longest history of endemic chagas disease, based on acute and chronic case reports, and of entomological surveys in the country. however, the state health care services need more information on current risks of vector transmission. in order to identify and charac ...200010759308
insecticide resistance in brazilian triatoma infestans and venezuelan rhodnius prolixus.resistance levels to insecticides used in control of chagas disease vectors were assessed in two species of bugs (hemiptera: reduviidae): triatoma infestans (klug) from brazil and rhodnius prolixus stål from venezuela. the resistance ratios, compared to susceptible laboratory strains, were determined by topical application bioassays. the t. infestans pa strain exhibited resistance ratios of 7x to deltamethrin, 3.6x to beta-cyfluthrin and 3.3x to cypermethrin, but was susceptible to beta-cypermet ...200010759312
cleptohaematophagy of the triatomine bug belminus herreri.the triatomine bug belminus herreri, previously known only from panama, is reported for the first time from colombia. three adult b. herreri were collected from a chicken coop and a viable egg was found on a bactris palm at carmen municipality in humid forest zone at 680 m altitude. from 44 eggs produced, five progeny were reared to adulthood. during early instars they were unable to take bloodmeals directly from vertebrate hosts, but they fed successfully by cleptohaematophagy on blood from rep ...200010759319
purification, cloning, expression, and mechanism of action of a novel platelet aggregation inhibitor from the salivary gland of the blood-sucking bug, rhodnius prolixus.rhodnius prolixus aggregation inhibitor 1 (rpai-1), a 19-kda protein isolated from the salivary gland of r. prolixus, was purified by strong cation exchange and reverse-phase high performance liquid chromatographies. based on 49 amino-terminal amino acid sequences of rpai-1, primers were produced to generate probes to screen an r. prolixus salivary gland cdna library. a phage containing the full-length clone of rpai-1 codes for a mature protein of 155 amino acids. rpai-1 shows sequence homology ...200010777556
neural inhibition of the corpus allatum in the last larval instar differs from that in adults in the blood-feeding insect, rhodnius prolixus.an active corpus allatum (ca) in the blood feeding insect, rhodnius prolixus, releases a substance that inhibits metamorphosis in larvae, and activates egg production in adults. in adults, transecting the nervus corporis cardiacum ii's (nccii), which are attached posteriorly to each protocerebral lobe, greatly increases egg production indicating that the adult ca is activated and receives neural inhibition from cells associated with the nccii [chiang, arch. insect. biochem. physiol. 39:126-131 ( ...200010790180
haemozoin formation in the midgut of the blood-sucking insect rhodnius prolixus.malaria parasites digest haemoglobin and detoxify the free haem by its sequestration into an insoluble dark-brown pigment known as haemozoin (hz). until recently, this pigment could be found only in plasmodium parasites. however, we have shown that hz is also present in the midgut of the blood-sucking insect rhodnius prolixus [oliveira et al. (1999) nature 400, 517-518]. here we show that hz synthesis in the midgut of this insect is promoted by a particulate fraction from intestine lumen. haem a ...200010899317
nitrophorins and related antihemostatic lipocalins from rhodnius prolixus and other blood-sucking arthropods.recent gene sequence and crystal structure determinations of salivary proteins from several blood-sucking arthropods have revealed an unusual evolutionary relationship: many such proteins derive their functions from lipocalin protein folds. many blood-sucking arthropods have independently evolved the ability to overcome a host organism's means of preventing blood loss (called hemostasis). most blood feeders have proteins that induce vasodilation, inhibit blood coagulation, and reduce inflammatio ...200011058753
two different vibratory signals in rhodnius prolixus (hemiptera: reduviidae).in this study the substrate-borne stridulatory vibrations produced by rhodnius prolixus females were recorded and analysed in two different behavioural contexts. in the context of sexual communication females spontaneously stridulated to reject copulatory attempts performed by males. these male-deterring stridulations were fully effective: out of 61 attempts, no copulation occurred. these stridulations consisted of short series of repetitive syllables, each one composed by a single chirp. in the ...200011114389
high density of rhodnius prolixus in a rural house in colombia. 200011127235
an electron microscopic study of penetration by trypanosoma rangeli into midgut cells of rhodnius prolixus.the process of interaction of the choachi strain of trypanosoma rangeli with intestinal epithelial cells of rhodnius prolixus was analyzed in experiments carried out in vitro and in vivo. for the in vitro experiments small fragments of the anterior region of the posterior midgut were incubated in the presence of the parasites, fixed, and processed for observation with the scanning electron microscope. parasites attached to the surface of some epithelial cells, especially to the extracellular mem ...200111161989
amplification of a specific repetitive dna sequence for trypanosoma rangeli identification and its potential application in epidemiological investigations.trypanosoma rangeli can infect humans as well as the same domestic and wild animals and triatomine vectors infected by trypanosoma cruzi in central and south america. this overlapping distribution complicates the epidemiology of american trypanosomiasis due to the cross-reactivity between t. rangeli and t. cruzi antigens and the presence of conserved dna sequences in these parasites. we have isolated a t. rangeli-specific dna repetitive element which is represented in approximately 103 copies pe ...200011162365
serial heart rate changes in rats inoculated by conjunctival instillation of trypanosoma cruzi obtained from bug faeces.the cardiac effects of experimentally induced myocarditis, when the parasite is obtained from mouse blood, are well known. however, the consequences of the infection when the parasites are obtained from bug faeces are less well defined. in the present investigation, we have used the "y" strain of trypanosoma cruzi, which was maintained in rhodnius prolixus by repeated passages in mice. the faeces of 30 infected bugs were collected, the number of parasites counted and 4,000 parasites inoculated b ...200011175582
[natural trypanosoma cruzi infection of triatominae bugs associated with human habitations in mexico ].to estimate the prevalence of infection with trypanosoma cruzi in triatominae species frequently found in and around mexican dwellings, and to assess the frequency of triatominae in towns by state.200011201577
phylogeny and molecular taxonomy of the rhodniini derived from mitochondrial and nuclear dna sequences.eleven species of rhodnius and one of psammolestes were compared by dna sequence analysis of fragments of the mitochondrial large subunit ribosomal rna (mtlsurrna), the mitochondrial cytochrome b (mtcytb), and the d2 variable region of the 28s nuclear rna (d2), totaling 1,429 base pairs. the inferred phylogeny, using triatoma infestans as an outgroup, revealed two main clades within the rhodniini--one, including the prolixus group of species (rhodnius prolixus, rhodnius robustus, rhodnius neglec ...200011220761
heme biosynthesis and oogenesis in the blood-sucking bug, rhodnius prolixus.we have previously shown that the pathway of porphyrin synthesis operates in the blood feeding triatomine bug rhodnius prolixus but not in the cattle tick boophilus microplus. in the present paper we studied the correlation between heme synthesis and egg development in rhodnius. there is a sharp increase heme biosynthetic capability in the fat body (160%) and in the ovaries (360%) in response to a blood meal, as evaluated from the activity of the enzyme delta-aminolevulinate dehydratase (ec 4.2. ...200111222945
interrupting chagas disease transmission in venezuela.the interruption of vectorial transmission of chagas disease in venezuela is attributed to the combined effects of ongoing entomoepidemiological surveillance, ongoing house spraying with residual insecticides and the concurrent building and modification of rural houses in endemic areas during almost five decades. the original endemic areas which totaled 750,000 km(2), have been reduced to 365,000 km(2). during 1958-1968, initial entomological evaluations carried out showed that the house infesta ...200111246282
purification and characterization of a lipid transfer particle in rhodnius prolixus: phospholipid transfer.in this study we report the purification and characterization of a lipid transfer particle (ltp) from rhodnius prolixus hemolymph, and its participation in phospholipid and diacylglycerol transfer processes. (3)h-diacylglycerol labeled low density lipophorin from manduca sexta ((3)h-ldlp) was incubated with r. prolixus lipophorin (lp) in the presence of rhodnius hemolymph. following incubation and isolation, both lipoproteins showed equivalent amounts of (3)h-labeled lipids. hemolymph was subjec ...200111267895
bacterial symbiosis and paratransgenic control of vector-borne chagas disease.the triatomine vectors of chagas disease are obligate haematophagous insects, feeding on vertebrate blood throughout their entire developmental cycle. as a result of obtaining their nutrition from a single food source, their diet is devoid of certain vitamins and nutrients. consequently, these insects harbour populations of bacterial symbionts within their intestinal tract, which provide the required nutrients that are lacking from their diet. we have isolated and characterised symbiont cultures ...200111334952
differential susceptibility of triatomines of the genus rhodnius to trypanosoma rangeli strains from different geographical origins.the susceptibility of four rhodnius species to different trypanosoma rangeli strains was evaluated using both intracoelomic inoculation and oral infection. rhodnius prolixus, rhodnius domesticus, rhodnius neglectus and rhodnius nasutus were infected with trypanosoma rangeli macias (venezuela), choachi (colombia) and sc-58 (brazil) strains, revealing distinct haemolymph and salivary glands infection rates. the obtained infection rates were revealed to be dependent on the method of infection and t ...200111334954
identification of a new water channel (rp-mip) in the malpighian tubules of the insect rhodnius prolixus.malpighian tubules (mt) of rhodnius prolixus transport fluid at very high rates. to identify whether aquaporins (aqps) are present in the mt of r. prolixus, total ribonucleic acid (rna) was isolated from mt and used in a reverse transcription, polymerase chain reaction (rt-pcr), with two degenerate primers to highly conserved regions of the members of the aqps family. a deoxyribonucleic acid (dna) fragment of 370 bp was amplified; its sequence revealed a novel protein, representing a new member ...200111374065
comparison of polymerase chain reaction on fresh tissue samples and fecal drops on filter paper for detection of trypanosoma cruzi in rhodnius prolixus.pcr detection of trypanosoma cruzi in rhodnius prolixus using fresh tissue or fecal drops on filter paper showed comparable results: 38.7% infection rate using the fresh tissue sample and 37.9% by dried fecal drop.200111391422
role of superoxide and reactive nitrogen intermediates in rhodnius prolixus (reduviidae)/trypanosoma rangeli interactions.this study compares aspects of the superoxide, nitric oxide and prophenoloxidase pathways in rhodnius prolixus hemolymph, measured in parallel, in response to trypanosoma rangeli inoculation. responses to two strains of t. rangeli, and two developmental forms, were studied, and the results obtained were correlated with the ability of the parasites to survive, multiply, and complete their life cycles in the hemolymph of the host. t. rangeli h14 strain parasites, which fail to complete their life ...200111426951
testis ecdysiotropin, an insect gonadotropin that induces synthesis of ecdysteroid.testes of lepidoptera synthesized ecdysteroid in a somewhat different temporal pattern than the prothoracic glands that release ecdysteroid to the hemolymph. brain extracts from heliothis virescens and lymantria dispar induced testes to synthesize ecdysteroid, but did not affect prothoracic glands. the testis ecdysiotropin (lte) was isolated from l. dispar pupal brains by a series of high-pressure chromatography steps. its sequence was ile-ser-asp-phe-asp-glu-tyr-glu-pro-leu-asn-asp-ala-asp-asn- ...200111462222
assessment of hepatitis b virus dna and hepatitis c virus rna in the common bedbug (cimex lectularius l.) and kissing bug (rodnius prolixus).historical clinical studies suggest the potential for insect-borne transmission of human hepatitis viruses. studies of hepatitis b virus (hbv) persistence in insects were performed before the advent of molecular techniques, and studies to assess possible insect-borne transmission of hepatitis viruses have not yet been performed. the aim of this study was to determine, using molecular techniques, whether hbv and hepatitis c virus (hcv) persist in and are excreted in the feces of the bedbug cimex ...200111467652
transfer of phospholipids from fat body to lipophorin in rhodnius prolixus.32p-labeled fat bodies (32p-fat bodies) of rhodnius prolixus females were incubated in the presence of non radioactive purified lipophorin and the release of radioactivity to the medium was analysed to answer the question of whether lipophorin is a reusable shuttle for phospholipids. the radioactivity found in the medium was associated with lipophorin phospholipids. when the 32p-fat bodies were incubated in the absence of lipophorin, only a small amount of radioactivity was released and it was n ...199211488301
loading of lipophorin particles with phospholipids at the midgut of rhodnius prolixus.32p-labelled midguts (32p-midguts) of rhodnius prolixus females were incubated in the presence of nonradioactive purified lipophorin and the release of radioactivity to the medium was analysed. the radioactivity found in the medium was associated with lipophorin phospholipids. when the 32p-midguts were incubated in the absence of lipophorin, no 32p-phospholipids were found in the medium. comparative analysis by thin-layer chromatography of 32p-phospholipids derived from metabolically labelled 32 ...199511488302
characterization and immunocytochemical localization of lipophorin binding sites in the oocytes of rhodnius prolixus.purified lipophorin, metabolically labelled with 32p exclusively in the phospholipid moiety, was used to study the process of phospholipid delivery to the oocyte. the kinetics of phospholipid transfer "in vitro," from lipophorin to the oocytes, was linear at least up to 4 h and was impaired by low temperature. a net transfer of phospholipids from lipophorin particles to the oocytes was observed. the rate of phospholipid uptake was dependent on the concentration of lipophorin in the medium and wa ...199611488303
ligand-induced heme ruffling and bent no geometry in ultra-high-resolution structures of nitrophorin 4.the nitrophorins are a family of proteins that use ferric heme to transport nitric oxide (no) from the salivary glands of blood-sucking insects to their victims, resulting in vasodilation and reduced blood coagulation. we have refined atomic resolution structures of nitrophorin 4 (np4) from rhodnius prolixus complexed with no (1.08 a) and nh(3) (1.15 a), yielding a highly detailed picture of the iron coordination sphere. in np4-no, the no nitrogen is coordinated to iron (fe-n distance = 1.66 a) ...200111560480
hydrogen peroxide detoxification in the midgut of the blood-sucking insect, rhodnius prolixus.here we investigated h2o2 production and detoxification in the hematophagous hemiptera, rhodnius prolixus. superoxide dismutase (sod) catalyzes the dismutation of superoxide radical (o2-). this reaction produces hydrogen peroxide, which is scavenged by antioxidant enzymes such as catalase (cat). sod and cat activities were found in all tissues studied, being highest in the midgut. cat was dose-dependently inhibited in vivo by injections of 3-amino-1,2,4-triazole (at). insects treated with at sho ...200111568965
cytoskeleton elements mediate the inhibition of the (na++k+)atpase activity by pkc in rhodnius prolixus malpighian tubules during hyperosmotic shock.in a previous paper, we observed that the specific activity of (na++k+)atpase of the isolated malpighian tubules from rhodnius prolixus is inhibited by protein kinase c (pkc) during hyperosmotic shock [arenstein et al., j membr biol 146:47-57 [1995]; caruso-neves et al., z naturforsch 53c:911-917 [1998]). in the present paper, we study the involvement of the cytoskeleton in this process using isolated malpighian tubules of rhodnius prolixus. we observed that pre-incubation of the malpighian tubu ...200111568967
mitochondrial dna sequences of triatomines (hemiptera: reduviidae): phylogenetic relationships.the phylogenetic relationships among 18 species of triatominae were inferred based on mitochondrial dna (mtdna) sequences. the species of triatoma included 11 belonging to the infestans complex [t. infestans (klug), t. guasayana wygodzinsky & abalos, t. sordida (stål), t. platensis neiva, t. brasiliensis neiva, t. rubrovaria (blanchard), t. vitticeps (stål), t. delpontei romaña & abalos, t. maculata (erichson), t. patagonica del ponte, and t. matogrossensis leite & barbosa] and four others of th ...200111580040
seroprevalence of human trypanosoma cruzi infection in diferent geografic zones of chiapas, mexico.a serologic survey was carried out in four different geographic zones of chiapas, mexico. a total of 1,333 samples were collected from residents of thirteen communities located on the coast, central mountain, lacandon forest and a zone called mesochiapas. one hundred and fifty one seropositive individuals (11.3%) were identified. human trypanosoma cruzi infection was influenced by geography. in the lacandon forest and central mountains there was a higher seroprevalence 32.1 and 13.8% respectivel ...200111600911
kdna markers define two major trypanosoma rangeli lineages in latin-america.trypanosoma rangeli is a hemoflagellate parasite of man, domestic and wild animals in central and south america. the genus rhodnius is particularly susceptible to infection by t. rangeli and transmission by salivary inoculation has been demonstrated in 12 of 14 nominal species of naturally and experimentally infected insects. this report describes the molecular characterization of 37 strains of t. rangeli isolated from vertebrate and invertebrate hosts. strains were analyzed by hybridization wit ...200211755434
movement of rhodnius prolixus (hemiptera: reduviidae) within a simulated house environment.we observed the movement, attraction, and resting behavior of laboratory rhodnius prolixus stål within a house environment, simulated by a styrofoam box. movement of r. prolixus into various refuge types (fiberpots or white-, cream-, or black-colored modified gomez-nunez boxes) at different strata was assessed. greater numbers of fifth instars sought a refuge than third instars. fasted nymphs sought a refuge more than fed nymphs. our simulated house environment showed potential as a laboratory a ...200111761381
differentiation and genetic analysis of rhodnius prolixus and rhodnius colombiensis by rdna and rapd amplification.domiciliated rhodnius prolixus and sylvatic r. colombiensis were analyzed in order to confirm their genetic divergence and verify the risk that the latter represents in the domiciliation process, and to provide tools for identifying the sources of possible reinfestation by triatomines in human dwellings allowing control programs to be undertaken. comparison of random amplified polymorphic dna amplification patterns and cluster analysis suggests reproductive discontinuity between the two species. ...200111784920
characterization of a cdna encoding a cathepsin l-like protein of rhodnius prolixus.the interaction of rhodnius prolixus digestive enzymes with trypanosoma cruzi could be important for parasite survival. we report herein the complete sequence of the messenger of a cathepsin l-like molecule (rpcat). the cdna has 5'- and 3'- end utrs and a methionine codon that corresponds likely to a translation initiation codon. in the deduced amino acid sequence, a region corresponding to an erfinin domain, diagnostic of l-cathepsins, and a possible pro-peptide cleavage site were observed. at ...200111881815
rhodnius heme-binding protein (rhbp) is a heme source for embryonic development in the blood-sucking bug rhodnius prolixus (hemiptera, reduviidae).we have previously shown that rhodnius prolixus' eggs and hemolymph are pink due to the presence of the hemeprotein rhodnius heme-binding protein (rhbp). in the hemolymph it functions as an antioxidant. nevertheless, its function in eggs has not been determined. here we present evidence that rhbp is a source of heme for embryonic development. rhbp content decreases during embryogenesis, but the total heme content of eggs remains unchanged. biliverdin, the product of heme degradation, is not dete ...200211886770
incidence of trypanosoma cruzi infection in two guatemalan communities.the prevalence of human infection by trypanosoma cruzi was assessed using an enzyme-linked immunosorbent assay (elisa) in a serological survey in 1998 of 2 rural communities (smh and ps) in guatemala. in smh (department of zacapa), where rhodnius prolixus was the principal vector, the seroprevalence amongst 373 people tested was 38.8%. in ps (department of santa rosa), where the main vector was triatoma dimidiata, 8.9% of the 428 people tested were seropositive. the overall prevalence of seropos ...200211925991
a reinvestigation of brindley's gland exocrine compounds of rhodnius prolixus (hemiptera: reduviidae).a chemical, electrophysiological and behavioral study was carried out to analyze the volatile compounds of the brindley's gland of rhodnius prolixus stål. six compounds were found in the brindley's gland of males and females: acetic, isobutyric, caproic acids and three compounds not identified. the mass spectra of the unidentified compounds have the appearance of a propionate ester, a butyrate ester and a valerate ester. there was no difference in the concentration of these compounds in the glan ...200211931024
lack of manipulation of rhodnius prolixus (hemiptera: reduviidae) vector competence by trypanosoma cruzi.behavioral implications of trypanosoma cruzi chagas infection in rhodnius prolixus stål were observed. feeding and defecation behaviors of infected versus uninfected insects were assessed on an artificial membrane-feeding system and on live guinea pigs. based on a defecation index, fifth instars were the most efficient vectors, followed by adult females, fourth instars, and adult males. bugs fasted for longer periods (5-6 mo) took smaller blood meals but defecated significantly earlier than bugs ...200211931271
[effect of human blood feeding on the fecundity, fertility and biological cycle of rhodnius prolixus (hemiptera: reduviidae)].the effect of several human blood fractions artificially fed to rhodnius prolixus stal 1859 on oviposture (fecundity), egg-hatching (fertility) and life cycle was observed. specimens fed on man's blood were more fecund than those fed with woman's blood. there were no significant differences in fertility related to host sex. the nymphal development time and number of feedings to molt to the following instar were estimated. animals fed only on blood plasm did not finish nymphal development, while ...200111935922
[feeding and defecation of rhodnius (hemiptera: reduviidae) fed human blood].feeding and defecation behavior of rhodnius prolixus stal, 1859, r. robustus larrousse, 1927, r. neivai lent, 1953 and r. pictipes stal, 1872, artificially fed on human blood, were studied under laboratory conditions. in all species, first instar nymphs did not defecate in the first 30 minutes after feeding. r. pictipes did not accept artificial feeding but fed directly on humans. nymph and adult r. prolixus had a higher defecation index (di) than other species; third instar nymphs had the highe ...200111935923
a multidisciplinary approach to the study of the fluminense vegetation.the fluminense vegetation, more specifically the flora from the jurubatiba restinga has been investigated by a multidisciplinary team of botanists, chemist, radiobiologist, insect physiologists and geneticist. vouchers of 564 specimens have been collected, identified, organized in an herbarium, and a database is being build up containing, in addition to classical botanical data, chemical data and information on the potential economic use either for landscape gardening, alternative foods or as me ...200211960185
allozyme relationships among ten species of rhodniini, showing paraphyly of rhodnius including psammolestes.genetic relationships among 10 species of bugs belonging to the tribe rhodniini (hemiptera: reduviidae), including some important vectors of chagas disease, were inferred from allozyme analysis of 12 enzyme loci (out of 21 enzyme systems examined), using agarose gel electrophoresis. these species formed two clusters: one comprising rhodnius brethesi, r. ecuadoriensis, r. pallescens and r. pictipes; the other with psammolestes tertius, rhodnius domesticus and the rhodnius prolixus group comprisin ...200211963985
development of symbionts in triatomine bugs and the effects of infections with trypanosomatids.in the intestinal tract of fifth instars of the hematophagous reduviid bugs rhodnius prolixus and triatoma infestans blood ingestion induced an initial decrease of the concentration of the respective symbiotic bacteria rhodococcus rhodnii and nocardia sp. and then within 10 days a 15- or 18-fold increase of the total population/bug to about 0.8 x 10(9) colony-forming units in r. prolixus and 1.8 x 10(9) colony-forming units in t. infestans. about 95-99% of the total populations of both symbionts ...200211971650
activity and residual effect of two formulations of lambdacyhalothrin sprayed on palm leaves to rhodnius prolixus.the insecticidal activity and residual effect of two formulations of lambdacyhalothrin were evaluated with rhodnius prolixus; laboratory and field tests were conducted in the state of chiapas, mexico. the results indicate that the lethal concentrations of the active ingredient of sc (lc50 = 2.37 and lc90 = 8.5 mg, a.i./m2) were 4-8 times than those with the insecticide wp applied on r. prolixus bugs in palm leaves, a common building material for thatched roofs. other investigators in south ameri ...200212048565
nitric oxide limits parasite development in vectors and in invertebrate intermediate hosts.nitric oxide (no) possesses antiparasitic effects on both protozoa and metazoa in vertebrate definitive and intermediate hosts. inducible no limits parasite development also in rhodnius prolixus and anopheles stephensi, the natural vectors of human trypanosomiasis and malaria respectively, and in the snail biomphalaria glabrata, a natural invertebrate intermediate host of human schistosomiasis. therefore, no limits trypanosoma, plasmodium, and schistosoma development at all stages of the parasit ...200212049194
effects of gamma irradiation on the development of trypanosoma rangeli in the vector rhodnius prolixus.studies on the effects of gamma radiation on the infectivity of trypanosoma rangeli (strain h14) for the vector rhodnius prolixus revealed that (i) the ld(50) (lethal dose for 50% of bugs) for uninfected insects was 4147 rads; (ii) irradiated insects with a dose of 1200 rads subsequently infected with the flagellates exhibited a mortality of 45%, while uninfected irradiated insects showed a mortality of 5%, and infected nonirradiated insects exhibited 10% mortality; (iii) flagellates were presen ...200212095237
dynamic development of trypanosoma cruzi in rhodnius prolixus: role of decapitation and ecdysone therapy.decapitation and ecdysone therapy on the population dynamics of the trypanosoma cruzi dm28c clone in the stomach, small intestine and rectum of fifth-instar larvae of rhodnius prolixus were investigated. parasites were not found in the small intestine and rectum of decapitated insects after 10 days post-infection (p.i.). decapitated ecdysone-supplemented insects sustained the flagellate infection in both gut compartments. in the rectum, the population density of parasites increased 5-fold in ecd ...200212107464
identification and distribution of carbohydrate moieties on the salivary glands of rhodnius prolixus and their possible involvement in attachment/invasion by trypanosoma rangeli.in the present study, fitc-labelled lectins (wga, con a, pna, hpa, and tpa) were utilized to investigate carbohydrate residues on the surface of rhodnius prolixus salivary glands. the results revealed that the salivary glands are rich in carbohydrate moieties and the diversity in binding pattern of particular lectins showed the presence of specific carbohydrate residues in the basal lamina, muscle, and cell layers of the glands. subsequently, the sugars detected on the salivary gland surface wer ...200212128049
the impact of chagas disease control in latin america: a review.discovered in 1909, chagas disease was progressively shown to be widespread throughout latin america, affecting millions of rural people with a high impact on morbidity and mortality. with no vaccine or specific treatment available for large-scale public health interventions, the main control strategy relies on prevention of transmission, principally by eliminating the domestic insect vectors and control of transmission by blood transfusion. vector control activities began in the 1940s, initiall ...200212219120
inhibition of hemostasis by a high affinity biogenic amine-binding protein from the saliva of a blood-feeding insect.the saliva of the blood-feeding insect rhodnius prolixus contains numerous pharmacologically active substances. included among these are a number of lipocalin proteins that bind various ligands important in hemostasis and inflammation. one such protein is a biogenic amine-binding protein (abp) that binds serotonin, epinephrine, and norepinephrine. based on amino acid alignments, it is most similar to the nitrophorin group of lipocalins found in the same insect species. physiologically, this prot ...200312464610
characterization of lipophorin binding to the fat body of rhodnius prolixus.in insects, lipids are transported by a hemolymphatic lipoprotein, lipophorin. the binding of lipophorin to the fat body of the hematophagous insect rhodnius prolixus was characterized in a fat body membrane preparation, obtained from adult females. for the binding assay, purified lipophorin was radiolabelled in the protein moiety (125i-hdlp), and it was shown that iodination did not affect the affinity of the membrane preparation for lipophorin. under incubation conditions used, lipophorin bind ...200212530208
parasite polymorphism may serve to enhance fitness in different host environments.phenotypic expression of trans-sialidase (ts) by trypanosoma cruzi (silvio strain) is restricted to a subpopulation (20-30%) of broad trypomastigotes (ts+ parasites), while the larger subpopulation of slender trypomastigotes lacks ts expression (ts- parasites). rhodnius prolixus nymphs were infected with fractionated t. cruzi parasite populations (silvio strain). bugs ingesting ts- parasites produced significantly higher parasite loads than bugs ingesting either ts+ parasites or unfractionated p ...200212656128
prevention of the transmission of chagas' disease with pyrethroid-impregnated materials.interrupting the transmission of chagas' disease using insecticide-treated materials could be a cost-effective option, particularly for sylvatic vectors, which enter houses at night. a randomized trial was undertaken that included all houses in two communities in regions endemic for this disease, one in venezuela (50 houses) and one in colombia (47 houses). after a baseline study (including a short questionnaire survey, entomologic assessment, and chagas' disease serology), each household was ra ...200312685636
geographic distribution and morphometric differentiation of triatoma nitida usinger 1939 (hemiptera: reduviidae: triatominae) in guatemala.triatoma nitida was found in 14 (0.4%) out of 3,726 houses located in six departments across guatemala, which were surveyed from 1994 to 1998 by the man-hour collection method. compared to previous information, the distribution of t. nitida in guatemala has increased from five to nine departments; the species is present in mild climates at altitudes from 960 to 1,500 m. fourteen percent of the intradomestic t. nitida were infected with trypanosoma cruzi. the species was often found in conjunctio ...200312700860
lysophosphatidylcholine acts as an anti-hemostatic molecule in the saliva of the blood-sucking bug rhodnius prolixus.blood-sucking arthropods possess a variety of anti-hemostatic factors in their salivary glands to maintain blood fluidity during feeding. in this work we demonstrate the anti-hemostatic properties of lysophosphatidylcholine (lysopc) isolated from the salivary glands of rhodnius prolixus. first, we examined salivary glands of fourth and fifth instar nymphs for their phospholipid composition. the lumen displayed an accumulation of its phospholipid content, mainly phosphatidylcholine and lysopc, wi ...200312740385
molecular phylogeography of the amazonian chagas disease vectors rhodnius prolixus and r. robustus.the phylogeographical structure of the closely related species rhodnius prolixus and r. robustus is presented based on a 663-base pair (bp) fragment of the mitochondrial cytochrome b gene. twenty haplotypes were recovered from 84 samples examined, representing 26 populations from seven latin american countries. the resulting phylogenetic tree is composed of five major reciprocally monophyletic clades, one representing r. prolixus and four representing r. robustus. while r. prolixus is a very hom ...200312753218
impact of residual spraying on rhodnius prolixus and triatoma dimidiata in the department of zacapa in guatemala.as a vector control program to control chagas disease in guatemala, residual spraying of rhodnius prolixus and triatoma dimidiata was performed, and its impact was measured in the department of zacapa. in order to identify infested villages and determine the degree of infestation, a baseline entomological survey to identify municipalities infested with vectors followed by an additional vector survey in areas known to be infested was conducted. residual spraying using pyrethroid insecticides was ...200312764447
the interplay between patency, microsomal na(+)/k(+) atpase activity and juvenile hormone, in tenebrio molitor parasitized by hymenolepsis diminuta.beetles infected with metacestodes of the rat tapeworm, hymenolepis diminuta, exhibit reduced fecundity, due to alterations in vitellogenesis. follicle cell patency is retarded and inefficient vitellogenin uptake ensues. here, we have reassessed patency and its stimulation by jh iii at day 3 post-infection, when the most detrimental changes are observed in other ovarian processes. in rhodnius prolixus, patency is believed to be brought about by the action of a jh-dependent membrane-bound na(+)/k ...199712769895
immune responses in rhodnius prolixus: influence of nutrition and ecdysone.starved larvae of rhodnius prolixus, when challenged with enterobacter cloacae b12, had their mortality related to their period of starvation. r. prolixus larvae fed on plasma alone, compared with insects fed on whole blood, had their immune reactivity affected as shown by: (i) a significant reduction in the ability to produce cecropin-like and lysozyme activities in the haemolymph when inoculated with e. cloacae; (ii) a reduction in numbers of haemocytes and nodule formation following challenge ...199712770413
transformation of rhodococcus rhodnii, a symbiont of the chagas disease vector rhodnius prolixus, with integrative elements of the l1 mycobacteriophage.elimination of vector populations through the use of insecticides is the principal means of controlling chagas disease. because of the limitations of insecticide use, we have been developing a new potential method of control, to be used in conjunction with insecticide programs, a method which utilizes genetically modified symbiotic bacteria. these transformed bacteria can express anti-parasitic agents in the gut of the bug where the trypanosomes also are found. previous studies have shown that i ...200312809804
anti-complement activity in the saliva of phlebotomine sand flies and other haematophagous insects.the saliva of haematophagous insects has a series of pharmacological activities which may favour blood feeding. in the present study, an inhibitory effect on the complement system was observed in salivary extracts obtained from the phlebotomine sand flies lutzomyia longipalpis and lu. migonei. saliva from lu. longipalpis was capable of inhibiting both the classical and alternative pathways, while that from lu. migonei acted only on the former. other haematophagous insect species were screened fo ...200312885192
epidemiology of chagas disease in guatemala: infection rate of triatoma dimidiata, triatoma nitida and rhodnius prolixus (hemiptera, reduviidae) with trypanosoma cruzi and trypanosoma rangeli (kinetoplastida, trypanosomatidae).a five-year domiciliary collection in the 22 departments of guatemala showed that out of 4,128 triatomines collected, 1,675 were triatoma dimidiata (latreille, 1811), 2,344 were rhodnius prolixus stal 1859, and only 109 were t. nitida usinger 1939. the chagas disease parasite, trypanosoma cruzi, was found in all three species. their natural infection rates were similar in the first two species (20.6%; 19.1%) and slightly lower in t. nitida(13.8%). however there was no significant difference in t ...200312886407
pyrethroid-impregnated curtains for chagas' disease control in venezuela.the use of insecticide treated materials for the control of chagas' disease transmission is potentially a cost-effective and sustainable option where vectors are sylvatic. a study was undertaken in two rural chagas' disease endemic communities (96 households) of trujillo state, venezuela. after a baseline study (including a short questionnaire survey, assessment of housing conditions, vector behaviour and preferences in vector protection), 37 households were chosen at random for protection by im ...200312943974
arthropod transmission of rabbit papillomatosis.the virus of rabbit papillomatosis, a neoplastic disease studied intensively in relation to cancer because of its tendency toward malignant transformation, has been successfully transmitted by aedes aegypti, rhodnius prolixus, and triatoma infestans from papillomas induced in cottontail rabbits, and by the first species mentioned, from papillomas induced in domestic rabbits. this was accomplished by interrupted feeding, feeding after an interval of several days from the infective meal, or by app ...195813549638
[data on trypanosoma rangeli tejera, 1920, i. technic for obtaining it from the salivary gland of rhodnius prolixus]. 195813586728
synthesis of thiamine and folic acid by nocardia rhodnii, the micro-symbiont of rhodnius prolixus. 196013711570
[the influence of intestinal symbionts of rhodnius prolixus on trypanosoma cruzi]. 195913856183
[verification of extradomestic rhodnius prolixus in venezuela. preliminary report]. 196314112052
increased infectivity of a cyclically maintained strain of trypanosoma rangeli to rhodnius prolixus and mode of transmission by invertebrate host. 196414215475
mass rearing of rhodnius prolixus. 196414272468
[development of a new method for the evaluation of house infestation by rhodnius prolixus]. 196514334652
a simple apparatus for the artificial feeding of rhodnius prolixus (hemiptera, reduviidae). 196014399808
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