Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
|---|
| the crystal structure of nitrophorin 2. a trifunctional antihemostatic protein from the saliva of rhodnius prolixus. | nitrophorin 2 (np2) (also known as prolixin-s) is a salivary protein that transports nitric oxide, binds histamine, and acts as an anticoagulant during blood feeding by the insect rhodnius prolixus. the 2.0-a crystal structure of np2 reveals an eight-stranded antiparallel beta-barrel containing a ferric heme coordinated through his(57), similar to the structures of np1 and np4. all four rhodnius nitrophorins transport no and sequester histamine through heme binding, but only np2 acts as an antic ... | 2000 | 10884386 |
| synthesis of vitellogenin by the follicle cells of rhodnius prolixus. | the synthesis and secretion of vitellogenin by the ovary of rhodnius prolixus was investigated. using whole ovary or epithelial cells isolated from follicles of different sizes, it is shown that the follicle cells are a site of synthesis for this protein in the ovary. the ovaries or follicle cells were incubated in vitro with [(35)s]-methionine or (32)pi and the secretion of newly synthesized ovarian vitellogenin (o-vg) was estimated by the radioactivity associated with the immunoprecipitate or ... | 2000 | 10844247 |
| the insect salivary protein, prolixin-s, inhibits factor ixa generation and xase complex formation in the blood coagulation pathway. | prolixin-s is a salivary anticoagulant of the blood-sucking insect, rhodnius prolixus, and known as an inhibitor of the intrinsic xase. we report here its inhibitory mechanisms with additional important anticoagulation activities. we found prolixin-s specifically bound to factor ix/ixa in the presence of ca(2+) ions. light scattering and surface plasmon resonance studies showed that prolixin-s interfered with factor ix/ixa binding to the phospholipid membrane, indicating that prolixin-s inhibit ... | 2000 | 10692472 |
| fatty acid incorporation by rhodnius prolixus midgut. | [(14)c]oleic acid injected into the hemocoel of rhodnius prolixus females was shown to rapidly associate with lipophorin particles. half of the lipophorin-associated [(14)c]oleic acid was transferred in about 5 min to different organs, but the midgut was the main organ to take it up on day 10 after a blood meal. the rate of [(14)c]oleic acid incorporation by the midgut was high up to 15 min after injection and then declined. the [(14)c]oleic acid incorporated by the midgut was found in phospholi ... | 2000 | 10685097 |
| adenosine modulates the (na(+)+k(+))atpase activity in malpighian tubules isolated from rhodnius prolixus. | the role of adenosine on regulation of the (na(+)+k(+))atpase activity present in the malpighian tubules isolated from rhodnius prolixus was investigated. adenosine decreases the (na(+)+k(+)) atpase specific activity by 88%, in a dose-dependent manner, with maximal effect at a concentration of 10(-9) m. this effect was mimicked by n(6)-cyclohexyladenosine (cha) at 10(-8) m, an agonist for a(1) adenosine receptor, and was reversed by 10(-9) m 8-cyclopentyl-1,3-dipropylxanthine (dpcpx), an antagon ... | 2000 | 10644971 |
| [current situation with chagas disease vector control in the americas]. | this article identifies and describes various epidemiological aspects in the natural transmission of chagas disease in the americas. it also examines the relative importance of the principal vector species in the disease's transmission and the control levels that are feasible in each instance. estimations of the population at risk, number of infected cases, and number of chronic cases are presented. prospects for control are discussed on the basis of past results to predict the expected results ... | 2000 | 11119318 |
| differences of susceptibility of five triatomine species to pyrethroid insecticides - implications for chagas disease vector control. | as pyrethroids are presently the favored group of insecticides to control triatomines, we performed a series of bioassays to determine the intrinsic activity of some of the main compounds used in the control campaigns, against five of the main species of triatomines to be controlled. comparing the insecticides it can be seen that lambdacyhalothrin is more effective than the other three pyrethroids, both considering the ld50 and 99 for all the three species with comparable results. on triatoma in ... | 1999 | 10677770 |
| susceptibility and resistance to insecticides of chagas disease vectors. | chemical control of chagas disease vectors appears to be the best practical way to reduce the incidence of the disease. ddt was initially tested in the 1950s for the campaigns of control of chagas disease vectors. its low level of effectiveness against triatomine caused the failure of these control actions. hch was then introduced in the southern cone and dieldrin in the north of latinoamerica. starting in the late 1960s anticholinesterasic organophosphorus and carbamate compounds were introduce ... | 1999 | 10668241 |
| biochemical characterization of a thrombin inhibitor from the bloodsucking bug dipetalogaster maximus. | from the bloodsucking bug dipetalogaster maximus, a protein with anticoagulant activity was isolated and biochemically characterized. the isolated protein, named dipetalogastin, possesses an average molecular mass of 11.8 kd. its n-terminal sequence shows homology to rhodniin, a thrombin inhibitor isolated from the bug rhodnius prolixus. the in vitro anticoagulant activity of dipetalogastin occurs via the inhibition of thrombin. the anticoagulant and thrombin inhibitory potency of dipetalogastin ... | 1999 | 10702701 |
| the distribution and function of serotonin in the large milkweed bug, oncopeltus fasciatus. a comparative study with the blood-feeding bug, rhodnius prolixus. | the blood-feeding hemipteran, rhodnius prolixus, ingests a large blood meal at the end of each larval stage. to accommodate and process this meal, its cuticle undergoes plasticisation, and its gut and malpighian tubules respectively absorb and secrete a large volume of water and salts for rapid diuresis. serotonin has been found to be integral to the feeding process in this animal, along with a diuretic peptide(s). the large milkweed bug, oncopeltus fasciatus, tends to feed in a more continuous ... | 1999 | 12770278 |
| a new factor xa inhibitor (lefaxin) from the haementeria depressa leech. | the salivary complex of the leech haementeria depressa produces potent anticoagulant components. among them, a protein named lefaxin inhibits factor xa (fxa). lefaxin was purified to homogeneity from dissected salivary complexes by gel filtration in sephadex g-150 followed by two ion exchange chromatography steps in mono-q. inhibition of fxa by lefaxin was demonstrated by the inhibition of its amidolytic activity, measured with chromogenic substrate s-2765 (apparent k(i) of 4 nm), and of its abi ... | 1999 | 10595640 |
| functional binding of a vertebrate hormone, l-3,5,3'-triiodothyronine (t3), on insect follicle cell membranes. | a vertebrate hormone, l-3,5,3'-triiodothyronine (t3), induces volume reduction in the follicle cells of locusta migratoria and rhodnius prolixus. the effect of t3 on locust follicle cells is inhibited by ouabain and by antibodies raised against a membrane binding protein for juvenile hormone (jh). [125i]-t3 binds to membrane preparations of vitellogenic follicles in a specific and saturable fashion, with a kd in the low nanomolar range. t3 and jh iii exhibited equivalent abilities to compete for ... | 1999 | 10528413 |
| extracellular glutathione peroxidase from the blood-sucking bug, rhodnius prolixus | glutathione peroxidase (gpx) activity was measured in several tissues of the blood-sucking bug, rhodnius prolixus. in contrast to the pattern found in vertebrates, where gpx is predominantly intracellular, the highest levels of this enzyme in rhodnius were found in the hemolymph. the hemolymph glutathione-dependent peroxidase accepted both h(2)o(2) and t-butyl hydroperoxide as substrates. this fact, together with the absolute glutathione dependence, inhibition by mercaptosuccinate, insensitivity ... | 1999 | 10421891 |
| daily rhythm of responsiveness to prothoracicotropic hormone in prothoracic glands of rhodnius prolixus | the synthesis of ecdysteroids by the prothoracic glands (pgs) of rhodnius prolixus occurs with a circadian rhythm throughout most of larval-adult development. this rhythm is generated by a circadian oscillator within the pgs. the principle regulator of the pgs is the cerebral neuropeptide prothoracicotropic hormone (ptth), which is also known to be released with a circadian rhythm, but it has not been shown that these daily releases of ptth are detected by the pgs. the present report examines th ... | 1999 | 10398334 |
| the distribution of a crf-like diuretic peptide in the blood-feeding bug rhodnius prolixus. | the blood-feeding bug rhodnius prolixus ingests a large blood meal, and this is followed by a rapid diuresis to eliminate excess water and salt. previous studies have demonstrated that serotonin and an unidentified peptide act as diuretic factors. in other insects, members of the corticotropin-releasing factor (crf)-related peptide family have been shown to play a role in post-feeding diuresis. using fluorescence immunohistochemistry and immunogold labelling with antibodies to the locusta crf-li ... | 1999 | 10393817 |
| kinetic analysis on nitric oxide binding of recombinant prolixin-s, a nitric oxide transport protein from the bloodsucking bug, rhodnius prolixus. | kinetics of the no binding and removal reaction of recombinant prolixin-s (rprolixin-s) were analyzed using stopped-flow spectrophotometry. the reaction was observed as a biphasic process. the rate constant of the fast phase increased linearly as no concentration increased. the rate constant at the slow phase increased as no concentrations increased at low no concentration, then reached a plateau at high no concentration. these no dependencies of the reaction are characteristic of a bimolecular ... | 1999 | 10350624 |
| protein phosphorylation during rhodnius prolixus embryogenesis: protein kinase casein kinase ii activity. | protein kinase casein kinase ii (ck ii) activity was assayed during rhodnius prolixus embryogenesis. vitellin (vt) is the main endogenous substrate during the whole development. it is maximally phosphorylated at the third day of embryogenesis by ck ii and then its phosphorylation decreases to a basal level by the time of first instar eclosion. when dephosphorylated casein was used as an exogenous substrate a different profile of enzyme activity was obtained. ck ii activity increases on day 1 aft ... | 1999 | 10319435 |
| urate synthesis in the blood-sucking insect rhodnius prolixus. stimulation by hemin is mediated by protein kinase c. | hemin is a catalyst of the formation of reactive oxygen species. we proposed that hematophagous insects are exposed to intense oxidative stress because of hemoglobin hydrolysis in their midgut (petretsky, m. d., ribeiro, j. m. c., atella, g. c., masuda, h., and oliveira, p. l. (1995) j. biol. chem. 270, 10893-10896). we have shown that hemin stimulates urate synthesis in the blood-sucking insect rhodnius prolixus (graça-souza, a. v., petretsky, j. h., demasi, m., bechara, e. j. h., and oliveira, ... | 1999 | 10092654 |
| [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 ... | 1999 | 10668252 |
| biological factors involving trypanosoma cruzi life cycle in the invertebrate vector, rhodnius prolixus. | 1999 | 10677719 | |
| immunity in rhodnius prolixus: trypanosomatid-vector interactions. | 1999 | 10677721 | |
| 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 ... | 1999 | 10721518 |
| 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 ... | 1999 | 9924967 |
| 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 ... | 1999 | 9951960 |
| 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 ... | 1999 | 10092472 |
| 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 ... | 1999 | 10192653 |
| 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 ... | 1999 | 10206119 |
| 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 ... | 1999 | 10222183 |
| 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. | 1999 | 10223214 |
| 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 ... | 1999 | 10337105 |
| 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 ... | 1999 | 10344645 |
| 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 ... | 1999 | 10348991 |
| 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 ... | 1999 | 10366535 |
| 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 ... | 1999 | 10395540 |
| 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 ... | 1999 | 10466963 |
| 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 ... | 1999 | 10484156 |
| 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. | 1999 | 10501007 |
| 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 ... | 1999 | 10561601 |
| 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 ... | 1999 | 10585653 |
| nitrophorin-2: a novel mixed-type reversible specific inhibitor of the intrinsic factor-x activating complex. | nitrophorin-2 (np-2), isolated from salivary glands of the blood-sucking insect rhodnius prolixus, has been shown to be a specific inhibitor of the intrinsic factor x-(fx)-activating complex. the inhibitory effect of np-2 is most potent in the presence of both fviiia and phospholipids (artificial phospholipid vesicles or activated human platelets). detailed kinetic analyses of the inhibitory mechanism of np-2 demonstrated a decrease in both vmax and k(m) of activated fix-(fixa)-catalyzed fx acti ... | 1998 | 9692958 |
| the occurrence of rhodnius prolixus stal, 1859, naturally infected by trypanosoma cruzi in the state of rio de janerio, brazil (hemiptera, reduviidae, triatominae). | 1998 | 9698882 | |
| factors affecting conidial production of beauveria bassiana from fungus-killed cadavers of rhodnius prolixus. | the epizootic potential of beauveria bassiana for control of the triatomine vectors of chagas' disease was investigated by studying the effects of both biotic and abiotic factors on the recycling of a highly virulent fungal isolate from fungus-killed cadavers of rhodnius prolixus. the conidial production of b. bassiana from mummified cadavers of r. prolixus required high rh levels of at least 96.5% rh. at 97% rh and 25 degrees c, the amount of conidia per insect ranged from 5.3 x 10(6) (on first ... | 1998 | 9709008 |
| purification and cloning of the salivary nitrophorin from the hemipteran cimex lectularius. | cimex lectularius and rhodnius prolixus contain salivary nitric oxide (no) that may help them to feed on their vertebrate hosts by promoting vasodilation and inhibiting platelet aggregation. salivary no is associated with heme proteins (nitrophorins) that store and transport no from the insect salivary glands to the skin of the host. in this study, the salivary nitrophorin of cimex lectularius was purified by deae chromatography and reverse-phase high-performance liquid chromatography. the purif ... | 1998 | 9716517 |
| the crystal structure of nitrophorin 4 at 1.5 a resolution: transport of nitric oxide by a lipocalin-based heme protein. | nitrophorins are nitric oxide (no) transport proteins from the saliva of blood-feeding insects, which act as vasodilators and anti-platelet agents. rhodnius prolixus, an insect that carries the trypanosome that causes chagas' disease, releases four no-loaded nitrophorins during blood feeding, whereupon the ligand is released into the bloodstream or surrounding tissue of the host. histamine, a signaling molecule released by the host upon tissue damage, is tightly bound by the nitrophorins; this m ... | 1998 | 9782054 |
| beauveria bassiana (hyphomycetes) as a possible agent for biological control of chagas disease vectors. | beauveria bassiana (balsamo) vuillemin (isolate cg306) was tested on 3rd instars of 9 triatoma spp., 4 rhodnius spp., 2 panstrongylus spp. and dipetalogaster maxima (uhler) at 25 degrees c and 50% rh. quantitative sporulation of the fungus on cadavers was studied at 25 degrees c and 97% rh. mortality, estimates of survival time, and conidial production on cadavers differed significantly among the genera and species tested. panstrongylus herreri wygodzinsky, dipetalogaster maxima, triatoma pictur ... | 1998 | 9835689 |
| salivary heme proteins distinguish rhodnius prolixus from rhodnius robustus (hemiptera: reduviidae: triatominae). | rhodnius prolixus interpopulation variability was studied based on a new approach using salivary heme proteins (nitrophorins) electrophoresis in starch gel. we compared salivary proteins profiles of r. prolixus from three different laboratory colonies from honduras, venezuela, brazil and rhodnius robustus from venezuela, constructing a upgma. the honduran and venezuelan populations could not be distinguished from each other, but the brazilian population was well separated from the others. the hi ... | 1998 | 9879737 |
| uptake of rhodnius heme-binding protein (rhbp) by the ovary of rhodnius prolixus. | the uptake of rhbp (rhodnius heme-binding protein) by the ovaries of rhodnius prolixus was characterized. rhbp purified from occyte was labeled with 125i and used to study the process of uptake by the ovary in vivo and in vitro. after injection, the [125i]rhbp was readily removed from the hemolymph and accumulated especially in the ovary. the capacity of the ovary to take up [125i]rhbp from the hemolymph varied during the days following blood meal. it increased up to day 2, remained stable until ... | 1998 | 9880903 |
| 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 ... | 1998 | 9921310 |
| [wild vectors of chagas' disease in an urban area of manaus (am): flying activity during dry and rainy seasons]. | adults of rhodnius prolixus, r. pictipes and panstrongylus geniculatus found in houses in manaus have high rates of trypanosoma cruzi infection. rhodnius spp. were found throughout the year, but males of p. geniculatus were significantly more frequent in the dry season. | 1998 | 9477705 |
| random amplification of polymorphic dna as a tool for taxonomic studies of triatomine bugs (hemiptera: reduviidae). | eleven of 27 decameric primers were found to be suitable for random amplification of polymorphic dna (rapd) from triatomine bugs on the basis that they produced discrete profiles and distinguished among panstrongylus megistus (burmeister), rhodnius prolixus stål, and triatoma infestans (klug). the legs, or single leg segments, of individual bugs were used as the source of dna so that the taxonomic value of the bug was conserved. within the scope of the specimens studied, rapd profiles allowed as ... | 1998 | 9542343 |
| the effects of aposymbiosis and of an infection with blastocrithidia triatomae (trypanosomatidae) on the tracheal system of the reduviid bugs rhodnius prolixus and triatoma infestans. | we have investigated the effects of the absence of symbionts and of infection with a trypanosome on the tracheal supply to different organs in larvae of the blood-sucking bugs, rhodnius prolixus and triatoma infestans. in bugs grown without symbionts there were extensive reductions in the tracheal supply to all the internal organs examined. these bugs also excreted less fluid after blood meals, perhaps because of a reduction in the oxygen supply to the malpighian tubules. inclusion of vitamin b ... | 1998 | 12769885 |
| ouabain-insensitive na(+)-atpase activity of malpighian tubules from rhodnius prolixus. | in the present paper, we show the existence of a furosemide-sensitive na(+)-stimulated, mg(2+)-dependent atpase activity in cell lysates of malpighian tubular cells from rhodnius prolixus, which could be the biochemical expression of the na(+)-pump. the main characteristics of this activity are: (1) k0.5 for na+ = 1.49 +/- 0.18 mm, (2) vmax = 2.8 +/- 0.1 nmol inorganic orthophosphate (pi).mg prot-1.min-1, (3) it is fully abolished by 2 mm furosemide, (4)it is insensitive to ouabain concentration ... | 1998 | 9787771 |
| characterization and cdna cloning of a hemoprotein in the salivary glands of the blood-sucking insect, rhodnius prolixus. | three major red hemoproteins, named rpsg i, ii (identical with prolixin-s) and iii, in the salivary glands of the blood-sucking insect, rhonius prolixus, show homology in n-terminal amino acid (aa) sequences, and are immunologically related. we focussed on one of these proteins, rpsg-i, in this paper. rpsg-i in fresh salivary gland extract was separated into two components (ia and ib) by isoelectric focussing gel electrophoresis. absorption spectra of rpsg-ia and ib showed soret peaks at 400 nm ... | 1998 | 9654741 |
| the origin of rhodnius prolixus in central america. | 1998 | 9580149 | |
| crystal structures of a nitric oxide transport protein from a blood-sucking insect. | the nitrophorins are heme-based proteins from the salivary glands of the blood-sucking insect rhodnius prolixus that deliver nitric oxide gas (no) to the victim while feeding, resulting in vasodilation and inhibition of platelet aggregation. the nitrophorins also bind tightly to histamine, which is released by the host to induce wound healing. here we present three crystal structures of nitrophorin 1 (np1): bound to cyanide, which binds in a manner similar to no (2.3 a resolution); bound to hist ... | 1998 | 9546222 |
| comparative kinetics of bloodmeal intake by triatoma infestans and rhodnius prolixus, the two principal vectors of chagas disease. | chagas disease vector insects triatoma infestans and rhodnius prolixus (fifteen stage iii nymphs per 4 litre cage) were allowed to feed on anaesthetized mice for 1 h (control group), or on active non-anaesthetized mice (nam) for 2, 4 or 8 h exposure. the bloodmeal size (weight increase) for both species was proportional to the duration of contact with nam, due to ingestion of multiple small bloodmeals, up to 142% of control weight for t. infestans with 8 h exposure to nam. the mean weight increa ... | 1998 | 9513943 |
| anti-diuresis in the blood-feeding insect rhodnius prolixus stål: antagonistic actions of camp and cgmp and the role of organic acid transport. | secretion of primary urine by upper malpighian tubules of the blood-sucking insect rhodnius prolixus has recently been shown to be inhibited by cyclic gmp (cgmp). in the present work, we have demonstrated that cgmp has effects antagonistic to those of camp in rhodnius tubules and have further characterized the effects of cgmp on tubular secretion. cyclic gmp inhibited secretion at all concentrations from 5x10(-6) to 10(-3)m, though this inhibition was partially or wholly reversed by large (2mm) ... | 1998 | 12769938 |
| role of the head in the ultrastructural midgut organization in rhodnius prolixus larvae: evidence from head transplantation experiments and ecdysone therapy. | studies on the effects of decapitation, head transplantation and ecdysone therapy on the ultrastructural organization of the midgut in 5th-instar larvae of rhodnius prolixus, were carried out. control insects had a typical and significant organization of the epithelial cells (mainly microvilli, extracellular membrane layers and basal portion of the epithelial cells) of the midgut (stomach and intestine) during the entire period of the experiment. however, the host larvae, when decapitated 1 day ... | 1998 | 12769937 |
| feeding is not necessary for triggering plasticization of the abdominal cuticle in haematophagous bugs. | a simple device was used to quantify changes in the mechanical properties of the cuticle of rhodnius prolixus and triatoma infestans that take place when these insects feed, i.e., plasticization. different stimuli were presented for 1min to test for their ability to trigger plasticization. these were: a blood meal, a ringer solution meal, contact with a warm surface and thermal stimulation without such contact. our results supplant any previous hypotheses that have supposed that the presence of ... | 1998 | 12770155 |
| rhythmic steroidogenesis by the prothoracic glands of the insect rhodnius prolixus in the absence of rhythmic neuropeptide input: implications for the role of prothoracicotropic hormone. | circadian rhythms have been reported both in the synthesis of the insect steroid moulting hormones (ecdysteroids) by the prothoracic glands (pgs) and in the release of the cerebral neuropeptide, prothoracicotropic hormone (ptth). ptth is known to activate steroidogenesis early in development, but the function of continued rhythmic release is unknown. the functional relationship between these two hormonal rhythms was examined. we report the properties of the rhythm of steroidogenesis by pgs of an ... | 1997 | 9405112 |
| anti-diuresis in the blood-feeding insect rhodnius prolixus stål: the peptide cap2b and cyclic gmp inhibit malpighian tubule fluid secretion. | rhodnius prolixus eliminates nacl-rich urine at high rates following its infrequent but massive blood meals. this diuresis involves stimulation of malpighian tubule fluid secretion by diuretic hormones released in response to distention of the abdomen during feeding. the precipitous decline in urine flow that occurs several hours after feeding has been thought until now to result from a decline in diuretic hormone release. we suggest here that insect cardioacceleratory peptide 2b (cap2b) and cyc ... | 1997 | 9316268 |
| role of phospholipids in the protein stability of an insect lipoprotein, lipophorin from rhodnius prolixus. | lipophorin (lp) is the major lipoprotein in insect hemolymph. the structural organization proposed for lp is basically the same as that suggested for vertebrate lipoproteins, consisting of a hydrophobic core containing neutral lipids, stabilized in the aqueous environment by surrounding polar moieties of protein and phospholipids at the particle surface. after complete removal of phospholipids from lp by phospholipase a2, the particle remains soluble [gondim, k. c., atella, g. c., kawooya, j. k. ... | 1997 | 9287164 |
| kcl reabsorption by the lower malpighian tubule of rhodnius prolixus: inhibition by cl(-) channel blockers and acetazolamide. | iono- and osmoregulation by the blood-feeding hemipteran rhodnius prolixus involves co-ordinated actions of the upper and lower malpighian tubules. the upper tubule secretes ions (na(+), k(+), cl(-)) and water, whereas the lower tubule reabsorbs k(+) and cl(-) but not water. the extent of kcl reabsorption by the lower tubule in vitro was monitored by ion-selective microelectrode measurement of cl(-) and/or k(+) concentration in droplets of fluid secreted by malpighian tubules isolated under oil. ... | 1997 | 12769977 |
| analysis of epithelial transport by measurement of k+, cl- and ph gradients in extracellular unstirred layers: ion secretion and reabsorption by malpighian tubules of rhodnius prolixus | summary the ph and concentrations of k+ and cl- in the unstirred layer (usl) associated with the basolateral surfaces of the upper and lower malpighian tubules of rhodnius prolixus were measured using extracellular ion-selective microelectrodes. when stimulated with 5-hydroxytryptamine (5-ht) in vitro, the upper malpighian tubule secretes na+, k+, cl- and water at high rates; the lower malpighian tubule reabsorbs k+ and cl- but not water. concentrations of k+ and cl- in the unstirred layer of th ... | 1997 | 9319533 |
| k+ reabsorption by the lower malpighian tubule of rhodnius prolixus: inhibition by ba2+ and blockers of h+/k+-atpases | active k+ reabsorption by the lower malpighian tubule of the blood-feeding hemipteran rhodnius prolixus does not involve the amiloride-sensitive k+/h+ exchangers or v-type h+-atpases implicated in secretion of ions from haemolymph to lumen in the upper tubule. amiloride, n-ethylmaleimide, 4-chloro-7-nitrobenzo-2-oxa-1,3-diazol and bafilomycin a1 inhibit haemolymph-to-lumen secretion of na+ and k+ by the upper malpighian tubule, but have little or no effect on lumen-to-haemolymph reabsorption of ... | 1997 | 9317503 |
| unipolar microtubule array is directly involved in nurse cell-oocyte transport. | the telotrophic ovariole of rhodnius prolixus is richly endowed with microtubules (mts). an extensive, stable array of mts packs the trophic core and trophic cords which link the nurse cell compartments to the growing oocytes. this system is excellent to study mt-based transport as the mts are believed to play a role in transport of nurse cell-produced mitochondria, ribosomes, and mrnas to the oocytes. we investigated mt polarity and molecular mt motors in this unidirectional transport system. h ... | 1997 | 9096957 |
| urate protects a blood-sucking insect against hemin-induced oxidative stress. | urate at high concentrations (up to 5 mm) is found in the hemolymph of the blood-sucking bug, rhodnius prolixus. increased urate levels are observed in the days following a blood meal. injecting hemin into the hemocoel increases both urate titer and tbars formation in the hemolymph. the urate response to hemin injection seems to arise from increased synthesis by the fat body as urate secretion by this organ is stimulated in vitro by incubation with hemin, and markedly counteracted by allopurinol ... | 1997 | 8958146 |
| ecdysteroidogenic action of bombyx prothoracicotropic hormone and bombyxin on the prothoracic glands of rhodnius prolixus in vitro. | an in-vitro assay for ecdysteroid synthesis by the prothoracic glands (pgs) of fifth instar rhodnius prolixus has been employed to evaluate the actions of prothoracicotropic neuropeptides from the silkmoth, bombyx mori. crude prothoracicotropic hormone (ptth) extracts of recently emerged adult brain complexes of bombyx induced a dose-dependent stimulation of ecdysteroid synthesis by rhodnius pgs, which was similar to that obtained using crude rhodnius ptth. in both cases, maximum stimulation was ... | 1997 | 12769976 |
| synanthropic rodent reservoirs of trypanosoma (schizotrypanum) cruzi in the valley of caracas, venezuela. | direct blood examination and xenodiagnosis of 47 synanthropic rodents (rattus rattus, r. norvegicus, mus musculus) captured in the valley of caracas, venezuela, revealed trypanosomal infections in 12 r. rattus, 10 with t. lewisi and 2 with t. cruzi. of the latter the course of parasitemia, the pleomorphism of the bloodstream trypomastigotes, tissue in naturally and experimentally infected rats and mice, host mortality, morphology of fecal parasites in rhodnius prolixus used for xenodiagnosis, an ... | 1997 | 9661306 |
| 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 ... | 1997 | 12769895 |
| 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 ... | 1997 | 12770413 |
| temperature and moisture requirements for conidial germination of an isolate of beauveria bassiana, pathogenic to rhodnius prolixus. | the effects of temperature, relative humidity and water activity on germination of conidia of an isolate of beauveria bassiana (bals.) vuill. pathogenic to the triatomine vector of chagas' disease, rhodnius prolixus stål., were investigated in vitro. germination occurred at temperatures between 15 degrees c and 35 degrees c under saturated atmosphere and the optima ranged from 25 degrees c to 30 degrees c. at the extreme temperatures tested (15 degrees c and 35 degrees c) the germination process ... | 1997 | 16283112 |
| effect of azadirachtin a on the fine structure of the midgut of rhodnius prolixus. | rhodnius prolixus fed with azadirachtin a showed significant changes in the ultrastructural organization of the epithelial cells of the stomach and the intestine. changes included (a) clustering of the microvilli, (b) disorganization of the extracellular membrane layers, (c) modifications in the array of spherocytes, and (d) disorganization of the basal portion of the epithelial cells. we suggest that these changes interfere significantly with the intestinal environment, making it unsuitable for ... | 1997 | 9028929 |
| prevention of insect-borne disease: an approach using transgenic symbiotic bacteria. | expression of molecules with antiparasitic activity by genetically transformed symbiotic bacteria of disease-transmitting insects may serve as a powerful approach to control certain arthropod-borne diseases. the endosymbiont of the chagas disease vector, rhodnius prolixus, has been transformed to express cecropin a, a peptide lethal to the parasite, trypanosoma cruzi. in insects carrying the transformed bacteria, cecropin a expression results in elimination or reduction in number of t. cruzi. a ... | 1997 | 9096383 |
| nitric oxide binding and crystallization of recombinant nitrophorin i, a nitric oxide transport protein from the blood-sucking bug rhodnius prolixus. | a nitric oxide transport protein (nitrophorin i) from the salivary glands of the blood-sucking bug rhodnius prolixus has been expressed as an insoluble form in escherichia coli, reconstituted with heme, and characterized with respect to no binding kinetics and equilibria. no binding and absorption spectra for recombinant nitrophorin i were indistinguishable from those of the insect-derived protein. the degree of no binding, the rate of no release, and the soret absorption maxima for nitrophorin ... | 1997 | 9109649 |
| biological effects of canatoxin in different insect models: evidence for a proteolytic activation of the toxin by insect cathepsinlike enzymes. | canatoxin is a toxic protein isolated from the jackbean, canavalia ensiformis. the toxin injected intraperitoneally is lethal for mice and rats; however, it is inactive if given orally. in this study, manduca sexta (l.) (lepidoptera), schistocerca americana (drury) (orthoptera), drosophila melanogaster (l.) (diptera), aedes aegypti (l.) (diptera), rhodnius prolixus (stål) (hemiptera), and callosobruchus maculatus (f.) (coleoptera) were fed on canatoxin-containing diets. no effects were seen in m ... | 1997 | 9145031 |
| lipophorin density variation during oogenesis on rhodnius prolixus. | the density of lipophorin was determined in adult females of rhodnius prolixus on different days after a meal. several populations od lipoproteins, differing in density but always in the range of hdl, were found in the hemolymph. the density of the major population was analyzed and a complex profile of density variation was found associated with the principal metabolic events in these insects digestion and oogenesis. during the initial three days after the blood meal, with the onset of the diges ... | 1997 | 9177134 |
| biomorphological alterations induced by an anti-juvenile hormonal compound, 2-(2-ethoxyethoxy)ethyl furfuryl ether, on three species of triatominae larvae (hemiptera, reduviidae). | applied topically to larvae of rhodnius prolixus stal, triatoma infestans (klug) and panstrongylus herreri wygodzinsky, vectors of trypanosoma cruzi, the causative agent of chagas' disease, a synthetic, furan-containing anti-juvenile hormonal compound, 2-(2-ethoxyethoxy)ethyl furfuryl ether induced a variety of biomorphological alterations, including precocious metamorphosis into small adultoids with adult abdominal cuticle, ocelli, as well as rudimentary adultoid wings. some adultoids died duri ... | 1997 | 9332589 |
| expression, reconstitution and characterization of prolixin-s as a vasodilator--a salivary gland nitric-oxide-binding hemoprotein of rhodnius prolixus. | prolixin-s, an anticoagulant from the salivary gland of the blood-sucking insect rhodnius prolixus is also one of the members of salivary gland hemoproteins. we produced recombinant protein using a baculovirus-insect cell expression system, reconstituted the hemoprotein and made some characterization of it as a nitric oxide carrier. the reconstituted protein exhibited the absorption spectrum of a high-spin ferric hemoprotein with a soret absorption peak at 400 nm. by binding nitric oxide (no-pro ... | 1997 | 9363788 |
| thrombin inhibitors of bloodsucking animals. | hematophagous animals have the unique ability to inhibit blood coagulation when sucking blood from a wound. this article concerns thrombin inhibitors from these animals, specifically the one from the insect rhodnius prolixus. to date, the most-studied inhibitor from these animals is hirudin, which specifically neutralizes thrombin but no other clotting serine proteases. the biochemical properties of hirudin are described. hirudinlike thrombin inhibitors from the asian leech hirudo manillensis, h ... | 1996 | 8807718 |
| [use of new tools for controlling triatomines in different entomologic situations in the american continent]. | the field results of new tools for triatomine control developed under the sponsorship of who/tdr are reported: a) a slow-release "paint" containing malathion; b) fumigant cans containing cypermethrin and ddvp, and c) sensor boxes for the detection of triatomine infestations. field assays were performed in chile, honduras and paraguay against triatoma infestans, t. dimidiata and rhodnius prolixus, accordingly to a standard protocol designed by a who experts committee. preliminary 6 months post-tr ... | 1996 | 9026830 |
| differential in vitro and in vivo behavior of three strains of trypanosoma cruzi in the gut and hemolymph of rhodnius prolixus. | a comparison was made of the agglutination and lysis of three strains of trypanosoma cruzi in gut extracts and hemolymph of rhodnius prolixus and the results obtained were correlated with the success or failure of the parasite strain to infect the digestive tube or to survive in the hemocel after inoculation. both t. cruzi strains dm28c and cl urine 35 days after feeding with parasites. concomitantly, both of these strains were agglutinated but not lysed by the crop extracts. in contrast, t. cru ... | 1996 | 8617337 |
| crystallographic evidence that the f2 kringle catalytic domain linker of prothrombin does not cover the fibrinogen recognition exosite. | the 2.6-a x-ray crystal structure of bovine alpha-thrombin in complex with rhodniin, a protein inhibitor isolated from the bug rhodnius prolixus, has been solved and refined. the structure has enabled us to trace the n-terminal part of the 49-residue a-chain of bovine alpha-thrombin for the first time, which is fixed in a u-shaped loop on the molecular surface opposite the active site canyon. model building shows that the 25 amino acid residues that link the a-chain and f2 kringle cannot run thr ... | 1996 | 8631941 |
| trypanosoma cruzi and erythrocyte agglutinins: a comparative study of occurrence and properties in the gut and hemolymph of rhodnius prolixus. | the activity of agglutinins found in the gut tissues and hemolymph of rhodnius prolixus was tested using rabbit erythrocytes, trypanosoma cruzi, or trypanosoma rangeli as test particles. in addition, investigations were made of the influence of parasitic infection and insect diet on the agglutination titers. a range of physicochemical tests and carbohydrate-binding studies were performed and inhibitors were subsequently found for both the crop agglutinin (p-nitrophenol-derived sugars) and the he ... | 1996 | 8654555 |
| 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 ... | 1996 | 11488303 |
| cdna cloning, expression and characterization of nitric-oxide synthase from the salivary glands of the blood-sucking insect rhodnius prolixus. | rhodnius prolixus, a blood-sucking bug, is a unique insect that is known to produce nitric oxide (no) in the salivary glands to use as a vasodilator for blood sucking. we report here the cloning of the no synthase (nos) cdna from these salivary glands and its expression in a baculovirus system. this cdna encodes a protein of 1174 amino acids with a calculated molecular mass of 132,331 da. the primary structures of mammalian nos, including the putative cofactor-recognition sites for heme, tetrahy ... | 1996 | 9022713 |
| isolation of a calcium-binding phosphoprotein from the oocytes and hemolymph of the blood-sucking insect rhodnius prolixus. | a novel calcium-binding phosphoprotein was isolated from the oocytes of the blood-sucking bug rhodnius prolixus. this protein exhibits an apparent molecular mass of 18 kda on gel filtration, but migrates as an 8-kda band on n-[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]glycine/sds-polyacrylamide gels. it has a high content of serine (24% of the total number of residues), and phosphoserine is the sole amino acid phosphorylated in vivo. a similar protein was partially purified from the hemolymph. it re ... | 1996 | 8939975 |
| the insect neuropeptide prothoracicotropic hormone is released with a daily rhythm: re-evaluation of its role in development. | prothoracicotropic hormone (ptth) is the central cerebral neurohormone in insect development. its release has been believed for decades to be confined to one (or two) critical moments early in each developmental stage at which time it triggers prolonged activation of the prothoracic glands to synthesize and release the steroid molting hormones (ecdysteroids), which elicit developmental responses in target tissues. we used an in vitro assay for ptth released from excised brains of the bug rhodniu ... | 1996 | 11607650 |
| circadian regulation of a daily rhythm of release of prothoracicotropic hormone from the brain retrocerebral complex of rhodnius prolixus (hemiptera) during larval-adult development. | a daily rhythm of release of prothoracicotropic hormone (ptth) has been reported throughout most of larval-adult development in rhodnius prolixus. ptth released by explanted brain-retrocerebral complexes was quantified using an in vitro bioassay in which the ptth released into the incubation medium was assayed by its ability to stimulate ecdysteroid synthesis in arrhythmic prothoracic glands (pgs). the present article employs this assay to reveal that the daily rhythm of ptth release is under ci ... | 1996 | 8860316 |
| purification, characterization and cdna cloning of a novel anticoagulant of the intrinsic pathway, (prolixin-s) from salivary glands of the blood sucking bug, rhodnius prolixus. | the salivary glands of the blood sucking insect, rhodnius prolixus, have an anticoagulant, prolixin-s, which was reported as a specific inhibitor of intrinsic coagulant pathway. prolixin-s was purified from the salivary glands extract of rhodnius prolixus by gel filtration and anion exchange hplc by assaying prolongation of activated partial thromboplastin time (aptt). the isolated protein specifically inhibited factor ixa-catalyzed activation of factor x in the presence of ca2+ and phospholipid ... | 1996 | 8743181 |
| the paracellular channel for water secretion in the upper segment of the malpighian tubule of rhodnius prolixus. | lumen to bath j12/c1 and bath to lumen j21/c2 fluxes per unit concentration of 19 probes with diameters (dm) ranging from 3.0-30.0 a (water, urea, erythritol, mannitol, sucrose, raffinose and 13 dextrans with dm 9.1-30.0 a) were measured during volume secretion (jv) in the upper segment of the malpighian tubule of rhodnius by perfusing lumen and bath with 14c or 3h-labeled probes. jnet = (j12/c1-j21/c2) was studied as a function of jv.jv was varied by using different concentrations of 5-hydroxy ... | 1995 | 8747555 |
| purification and characterization of prolixin s (nitrophorin 2), the salivary anticoagulant of the blood-sucking bug rhodnius prolixus. | the salivary anticoagulant of the blood-sucking bug rhodnius prolixus was purified to homogeneity using a protocol consisting of weak cation-exchange, deae, hydrophobic-interaction and octadecyl reverse-phase chromatography, yielding a protein with the same n-terminal sequence as nitrophorin 2, one of the four no haem protein carriers present in the salivary glands of rhodnius with a molecular mass of 19689 da [d. champagne, r.h. nussenzveig and j.m.c. ribeiro, (1995) j. biol. chem. 270, in the ... | 1995 | 7755571 |
| antioxidant role of rhodnius prolixus heme-binding protein. protection against heme-induced lipid peroxidation. | heme in aqueous solutions actively promotes free radical reactions leading to degradation of biological molecules. the blood-sucking insect rhodnius prolixus has a heme-binding protein (rhbp) in its hemolymph (oliveira, p.l., kawooya, j.k., ribeiro, j.m.c., meyer, t., poorman, r., alves, e.w., walker, f., padovan, g.j., and masuda, h. (1994) j. biol. chem. 270, 10897-10901. here we show that this protein inhibits heme-dependent peroxidation of both linolenic acid liposomes and lipophorin, the ma ... | 1995 | 7738029 |
| nitric oxide loading of the salivary nitric-oxide-carrying hemoproteins (nitrophorins) in the blood-sucking bug rhodnius prolixus. | the salivary glands of the blood-sucking bug rhodnius prolixus are formed by a single layer of binucleated epithelial cells surrounded by a double layer of transversely oriented smooth muscle cells. the epithelial cells are rich in rough endoplasmic reticulum and mitochondria and have abundant microvillar projections towards the gland lumen. this cell layer surrounds a relatively large cavity where abundant secretory material is stored. epithelial cells produce an intense and generalized nadph d ... | 1995 | 8627144 |
| purification, partial characterization, and cloning of nitric oxide-carrying heme proteins (nitrophorins) from salivary glands of the blood-sucking insect rhodnius prolixus. | four nitric oxide (no)-carrying proteins have been isolated from salivary glands of the blood-sucking insect rhodnius prolixus. these have been given the collective name "nitrophorins," and individual proteins are designated np1-np4 in order of their relative abundance in the glands. all four reversibly bind no; spectral shifts associated with no binding indicate the interaction of no with an fe(iii) heme. physical properties, amino acid composition, and amino-terminal sequences of the nitrophor ... | 1995 | 7721773 |
| the feeding stimulus in rhodnius prolixus is transmitted to the brain by a humoral factor | neurosecretory cells in the brain of rhodnius prolixus are known to be the source of an ovulation hormone released at feeding. they were selected to test the hypothesis that feeding brings about the release of another hormone in the abdomen which is transported forward to activate the neuroendocrine axis in the brain, and that severing the aorta interferes with this transport. these cells have previously been shown to exhibit an increase in action potential frequency at the time of release of th ... | 1995 | 9318904 |
| 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 ... | 1995 | 11488302 |
| lignanes from the brazilian melia azedarach, and their activity in rhodnius prolixus (hemiptera, reduviidae). | a study of the phagoinhibitor and anti-moulting activities of the brazilian melia azedarach, collected in the state of rio de janeiro, brazil, allowed the isolation of four lignanes identified as pinoresinol (1), bis-epi-pinoresinol (2), the hemicetal (3) and the diacid (4). these substances are devoid of anti-moulting activity. | 1995 | 8731373 |
| infectivity of trypanosoma rangeli in a promonocytic mammalian cell line. | the existence of an intracellular stage of trypanosoma rangeli in the vertebrate host was evaluated by experimental infection of the u937 histiocytic cell line with the san agustín strain and the ub66-5b clone. the identity of the parasites at the beginning and end of the experiments was confirmed through biological behavior in the vector and mammal hosts, isoenzymes, polymerase chain reaction (pcr), and monoclonal antibodies. infectivity to u937 cells of t. rangeli obtained from culture and sal ... | 1995 | 7472856 |
| two heads are better than one: crystal structure of the insect derived double domain kazal inhibitor rhodniin in complex with thrombin. | rhodniin is a highly specific inhibitor of thrombin isolated from the assassin bug rhodnius prolixus. the 2.6 angstrum crystal structure of the non-covalent complex between recombinant rhodniin and bovine alpha-thrombin reveals that the two kazal-type domains of rhodniin bind to different sites of thrombin. the amino-terminal domain binds in a substrate-like manner to the narrow active-site cleft of thrombin; the imidazole group of the p1 his residue extends into the s1 pocket to form favourable ... | 1995 | 7489704 |