Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| use of total parasite dna probes for the direct detection of trypanosoma cruzi and trypanosoma rangeli in domicilliary rhodnius prolixus. | 1990 | 2189249 | |
| the biochemical basis of tolerance to malathion in rhodnius prolixus. | 1. lc50 of malathion, fenitrothion and lindane were determined in r. prolixus and t. infestans. r. prolixus was shown to be tolerant to malathion. 2. the penetration rate of (14c)-malathion into r. prolixus and t. infestans was similar. 3. acetylcholinesterase from r. prolixus heads was 3.3-fold less sensitive to inhibition by malaoxon than the similar enzyme of t. infestans. 4. r. prolixus showed more activity of gsh-s-transferases against dcnb than t. infestans. 5. the in vitro degradation of ... | 1990 | 1703470 |
| circadian regulation of synthesis of ecdysteroids by prothoracic glands of the insect rhodnius prolixus: evidence of a dual oscillator system. | rhythmic synthesis of moulting hormones (ecdysteroids) by prothoracic glands (pgs) of the insect rhodnius prolixus during the last larval instar was studied in vitro following explantations every 4-5 hr for up to 96 hr. ecdysteroid synthesis was measured by radioimmunoassay as the quantity of ecdysteroid produced during 4 hr in vitro. a massive daily rhythm is seen, with synthesis at night being three- to fivefold higher than during the day. this rhythm of ecdysteroid synthesis by pgs free-runs ... | 1991 | 1879670 |
| 5-hydroxytryptamine: a second diuretic hormone in rhodnius prolixus. | bioassays of 5-hydroxytryptamine (5-ht) in fifth-instar rhodnius prolixus haemolymph using calliphora salivary glands indicate that: (1) biologically active 5-ht is present, (2) in unfed animals there is not enough 5-ht to stimulate malpighian tubule fluid secretion, and (3) there is enough 5-ht soon after the initiation of feeding to stimulate rapid tubule secretion. the 5-ht receptor antagonists ketanserin and spiperone reversibly and selectively inhibit 5-ht-induced fluid secretion, indicatin ... | 1991 | 2051136 |
| effects of proallatotoxins (precocenes) on the development and reproduction of rhodnius prolixus: some data. | proallatotoxins, and particularly precocenes, are exceptionally promising models for studying rhodnius prolixus physiology and for comparison with other natural compounds with antihormonal activities. effects of precocenes on feeding, development and reproduction of r. prolixus are being detailed. the precocenes reveal significant effects on feeding, moulting cycle (inducing precocious metamorphosis and ecdysial stasis), and reproduction of these insects. the mechanism of action of proallatotoxi ... | 1991 | 1841983 |
| lethality of triatomines (hemiptera: reduviidae), vectors of chagas' disease, feeding on blood baits containing synthetic insecticides, under laboratory conditions. | a laboratory study was conducted to test the toxicity of synthetic insecticides added to defibrinated sheep blood kept at room temperature and offered as food to the following triatomine species: triatoma infestans, panstrongylus megistus, triatoma vitticeps, triatoma pseudomaculata, triatoma brasiliensis and rhodnius prolixus. the insecticides used, at a concentration of 1 g/l, were: hch, ddt, malathion and trichlorfon, and the lethalithy observed at the end of a 7-day period varied according t ... | 1991 | 1726952 |
| effects of azadirachtin in rhodnius prolixus: data and hypotheses. | the effects of azadirachtin a, a tetranortriterpenoid from the neem tree azadirachta indica j., on both development and interaction between trypanosoma cruzi, the causative agent of chagas' disease, and its vector rhodnius prolixus were studied. given through a blood meal, a dose-response relationship of azadirachtin was established using antifeedant effect and ecdysis inhibition as effective parameters. a single dose of azadirachtin a was able to block the onset of mitosis in the epidermis and ... | 1991 | 1841982 |
| the distribution of agglutinins and lytic activity against trypanosoma rangeli and erythrocytes in rhodnius prolixus and triatoma infestans tissue extracts and haemolymph. | haemolymph, heads, salivary glands, crops, midguts, hindguts, and malpighian tubules from rhodnius prolixus and triatoma infestans were extracted in phosphate or tris buffer saline with calcium, and tested for agglutination and lytic activities by microtitration against both vertebrate erythrocytes and cultured epimastigote forms of trypanosoma rangeli. haemagglutination activity against rabbit erythrocytes was found in the crop, midgut and hindgut extracts of t. infestans but only in the haemol ... | 1991 | 1842412 |
| [behavior of trypanosoma cruzi strains after passage in different triatominae species]. | to study the influence of the intermediate host stage on the course of mouse infection, trypanosoma cruzi belonging to the peruvian (type i), 12 sf (type ii) and colombian (type iii) strains were passaged through either rhodnius prolixus, panstrongylus megistus or triatoma infestans. t. cruzi metacyclic forms (dose 10(4)) from the different strains were obtained from each bug and inoculated into 8-10 gm mice. comparison was made in mice inoculated with blood forms. parasitaemia curves were plott ... | 1991 | 1845005 |
| the prophenoloxidase system and in vitro interaction of trypanosoma rangeli with rhodnius prolixus and triatoma infestans haemolymph. | the presence of the prophenoloxidase (propo) system in the haemolymph of rhodnius prolixus and triatoma infestans and the role played by trypanosoma rangeli in the in vitro activation of propo were tested. both r. prolixus and t. infestans whole blood preparations showed a very active propo system. the propo cascade of the two insect species were differentially activated by microbial-derived extracts: laminarin was a better activator of t. infestans haemolymph than of r. prolixus blood, and lipo ... | 1991 | 1956701 |
| the fate of calcium in the diet of rhodnius prolixus: storage in concretion bodies in the malpighian tubules. | we have investigated the fate of the large amounts of calcium ingested by rhodnius prolixus in its meals of blood. 45ca2+ injected into the haemolymph or fed to fifth-stage rhodnius reared on rabbits is accumulated at high concentrations in the cells of the upper malpighian tubules; very little is excreted from the body this 45ca2+ accumulation goes on continuously for at least 12 days and the rate of uptake is increased several-fold within 3-4 days of a meal. the extent of calcium accumulation ... | 1991 | 2061707 |
| effects of azadirachtin on rhodnius prolixus: immunity and trypanosoma interaction. | the effects of azadirachtin, a tetranortriterpenoid from the neem tree azadirachta indica j., on both immunity and trypanosoma cruzi interaction within rhodnius prolixus and other triatomines, were presented. given through a blood meal, azadirachtin affected the immune reactivity as shown by a significant reduction in numbers of hemocytes and consequently nodule formation following challenge with enterobacter cloacae beta 12, reduction in ability to produce antibacterial activities in the hemoly ... | 1992 | 1342719 |
| [presence of neuraminidase in rhodnius prolixus infected with trypanosoma rangeli]. | using three different methods, the activity of neuraminidase was studied in the promesenteron, postmesenteron, rectal ampulla, haemolymph and salivary glands in 600 rhodnius prolixus experimentally infected with trypanosoma rangeli stock san agustín. the haemagglutination method with peanut lectin, and the fluorescence test with peanut lectin conjugated with fluorescein isothiocyanate, and the fluorescence emitted by 4-methylumbelliferone showed in all cases the presence of neuraminidase in the ... | 1992 | 1345317 |
| relative susceptibility of different stages of rhodnius prolixus to the entomopathogenic hyphomycete beauveria bassiana. | laboratory bioassays were conducted to determine the relative susceptibility of eggs, 1st-, 3rd-, 5th-instar nymphs and adults of rhodnius prolixus to one isolate of the entomopathogenic hyphomycete, beauveria bassiana. treatments consisted of directly spraying on insects of increasing doses of inoculum (3 x 10(2) to 3 x 10(5) conidia per cm2). mortality due to all doses of conidia was very high in the five tested stages of the target insect. experiments on eggs demonstrated that the fungal isol ... | 1992 | 1343645 |
| analytic morphometry of the trypanosoma cruzi (bolivia strain) forms found in the intestine of rhodnius prolixus. | 1992 | 1308547 | |
| [the epidemiology of chagas' disease in a rural area of the city of teresina, piauí, brazil]. | in the rural areas of teresina, 129 triatomines were captured distributed in (a) artificial ecotopes; a house with one triatoma brasiliensis, one panstrongylus geniculatus, rhodnius pictipes, and one rhodnius prolixus and in a uninhabited chicken house (7 rhodnius nasutus). (b) natural ecotopes; pahus orbignya martiana (41 rhodnius neglectus, 33 rhodnius prolixus and 41 rhodnius nasutus) and copernicia cerifera (3 rhodnius neglectus). the 22.6% of captured triatomines were infected by flagellate ... | 1992 | 1308066 |
| didelphis marsupialis: a primary reservoir of trypanosoma cruzi in urban areas of caracas, venezuela. | direct blood examination and xenodiagnosis of 45 sylvatic, peridomestic or domestic mammals from the caracas valley, venezuela, revealed trypanosome infection in six of the 24 opossums, didelphis marsupialis, collected in urban areas. isolates were successfully made of trypanosomes from four of the opossums, using the parasites which developed in rhodnius prolixus fed on the infected opossums to infect nmri mice. the prepatent period, course of parasitaemia, morphology of bloodstream trypomastig ... | 1992 | 1304702 |
| lethal effect of a bait for rhodnius prolixus (hemiptera: reduviidae), the vector of chagas' disease, containing hexachlorocyclohexane (hch), under laboratory conditions. | the lethal effect of a bait containing an aqueous hexachlorocyclohexane (hch) suspension at the concentration of 1g/l and maintained at room temperature was studied in the laboratory over a period of 12 weeks. the suspension was placed in a latex bag hanging inside a 1000-ml beaker tightly covered with nylon netting, and left there with no changes for 85 days. sixteen groups of r. prolixus bugs, consisting on average of 30 specimens each, were successively exposed to the bait and observed at dif ... | 1992 | 1285256 |
| a fmrfamide-like peptide is associated with the myotropic ovulation hormone in rhodnius prolixus. | the protocerebral neurosecretory cells previously shown to be the source of the myotropin controlling ovulation in rhodnius prolixus react in an immunocytochemical assay using an antiserum against fmrfamide. when the same antiserum was injected into fed mated females at the appropriate time the timing of oviposition was delayed, but the total number of eggs developed was unaffected compared to controls injected with pre-immune rabbit serum. the titer of fmrfamide-like peptide (assayed by ria) in ... | 1992 | 1450451 |
| autogeny in three species of triatominae: rhodnius prolixus, triatoma rubrovaria, and triatoma infestans (hemiptera: reduviidae). | autogeny, the capacity of a female to lay eggs without having ingested any blood meal in the adult stage, was studied in three species of triatominae: triatoma infestans, triatoma rubrovaria, and rhodnius prolixus. when nymphs of t. rubrovaria and r. prolixus were fed chicken blood, autogeny occurred frequently, even with only one meal. in t. infestans autogeny was frequent as well, but demanded at least two nymphal blood meals. total number of autogenic eggs was positively correlated with the b ... | 1992 | 1495041 |
| transformation of an insect symbiont and expression of a foreign gene in the chagas' disease vector rhodnius prolixus. | a shuttle plasmid was developed that is capable of replicating both in escherichia coli and in rhodococcus rhodnii, a bacterial symbiont of the chagas' disease vector rhodnius prolixus. we have been able to transform r. rhodnii with this plasmid, infect aposymbiotic r. prolixus with the transformed symbionts, select with the antibiotic thiostrepton, and re-isolate genetically altered symbionts from the insects following successive molts. symbiotic bacteria are potentially valuable as vehicles fo ... | 1992 | 1539755 |
| isozyme variability and differentiation between rhodnius prolixus, r.robustus and r.pictipes, vectors of chagas disease in venezuela. | enzyme polymorphism in triatomine bugs of the genus rhodnius (hemiptera: reduviidae), vectors of chagas disease, is analysed using both starch and polyacrylamide gel electrophoresis. out of forty-five enzymes assayed, the electromorphs of seventeen of them: ao, ca, dia, es, es-a, fh, gpd, g6pd, gpi, mdh, me, 6pgd, pgm, acon, acph, lap and sod, involving twenty-two putative structural loci, were scorable. these gene-enzyme systems were therefore selected for routine characterization of r.prolixus ... | 1992 | 1600225 |
| 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 ... | 1992 | 11488301 |
| spatial and temporal transcellular current patterns during oogenesis. | we have used the two-dimensional vibrating probe to examine spatial and temporal patterns in the transcellular current flow around telotrophic ovarioles of the insect rhodnius prolixus. we demonstrate a dynamic pattern of currents which correlates with various stages of vitellogenesis. asymmetries exist in the radial current pattern around intact ovarioles, particularly around the terminal follicle, and may correlate with early developmental axes. the extra-cellular current pattern is largely re ... | 1992 | 1397687 |
| insulin-like immunoreactivity and molting in rhodnius prolixus. | two prominent cells were observed when fifth stage rhodnius female larval brains were stained with anti-insulin serum. the staining intensity of these cells varied during the instar, being lowest on day 1 and days 5 and 6 after feeding. injection of anti-insulin serum into 5th stage larvae immediately after feeding and on days 4 and 5 in females and on days 5 and 6 in males prevented molting. control antiserum had no effect on the molting process. injections at other times during the instar had ... | 1992 | 1601272 |
| cell proliferation and rearrangement in the development of the malpighian tubules of the hemipteran, rhodnius prolixus. | the pattern of cell activities resulting in the generation of a simple tubular epithelium, the malpighian tubules of rhodnius prolixus, is examined during embryogenesis. the anlage of the tubules is shown to be of ectodermal origin. an evolving pattern of cycling cells in the primordia is revealed using the immunocytochemical localization of a substituted nucleotide, budr. a cell unique to each tubule is shown not to enter the cell cycle but to be required for the proliferation of the remaining ... | 1992 | 1551481 |
| in vitro photosensitivity of ecdysteroid synthesis by prothoracic glands of rhodnius prolixus (hemiptera). | the effects of light:dark transitions on in vitro ecdysteroid synthesis by prothoracic glands (pgs) of male fifth instar rhodnius have been studied. pgs were rendered arrhythmic by prolonged maintenance of the animals in continuous light (ll). pgs were then explanted and ecdysteroid synthesis was measured hourly by radioimmunoassay. pgs were transferred from ll to darkness at various times after explanation and hourly synthesis was measured for several more hours. transfer of pgs to darkness in ... | 1992 | 1505717 |
| role of phospholipids in the lipophorin particles of rhodnius prolixus. | the lipophorin of rhodnius prolixus metabolically labelled with 32p exclusively in the phospholipid moiety was purified on a potassium bromide gradient and treated with phospholipase a2 in the presence of an excess of fatty acid-free albumin. the treatment completely removed the phospholipids from the particles and generated [32p]-lysophosphatidylcholine, [32p]-lysophosphatidylethanolamine, and free fatty acids that remained bound to albumin. the phospholipid-depleted lipophorin particles remain ... | 1992 | 1504321 |
| identification of yolk platelet-associated hydrolases in the oocytes of rhodnius prolixus. | the yolk platelets from rhodnius prolixus, a blood-sucking bug, are composed mostly of vitellin and here are shown to contain at least two hydrolytic enzymes, a phosphatase and a cathepsin d-like proteinase. both the proteinase and the phosphatase have an acid ph optimum. no hydrolytic activity was observed under alkaline or neutral conditions. among several proteinase inhibitors tested, only pepstatin could abolish vitellin breakdown in vitro. the proteinase appears to be bound to the yolk plat ... | 1992 | 1286200 |
| feeding behavior of different species of chagas' disease vectors stimulated with blood sources at different temperatures. | 1. the feeding behavior of six triatomid species toward latex condoms filled with blood at 26 +/- 1 and 36 +/- 1 degrees c was observed for 4 h. 2. the species studied were triatoma infestans, triatoma brasiliensis, triatoma vitticeps, triatoma pseudomaculata, rhodnius prolixus and panstrongylus megistus, and 34 to 348 insects were studied in each group (average, 190). all the life stages of each species were used. 3. although most insects (80%, average for 6 species) preferred the warmer blood, ... | 1992 | 1304939 |
| dynamics of the oocyte cortical cytoskeleton during oogenesis in rhodnius prolixus. | the oocyte cortex undergoes dramatic changes during oogenesis in rhodnius prolixus. despite numerous studies examining oogenesis in the telotrophic ovariole, none has investigated the ultrastructural details of the oocyte cortex, in particular, the lateral cortical cytoskeleton. indirect immunofluorescent staining of sections, rhodamine phalloidin staining of whole mounts and scanning and transmission em of permeabilized and unpermeabilized preparations revealed the dynamic changes of the oocyte ... | 1993 | 18621240 |
| cdna cloning and expression of rhodnius prolixus vitellogenin. | it was shown that rhodnius prolixus vitellogenin (vg) is synthesized as precursors of 205 and 190 kda. each vg subunit is antigenically related to a domain in the precursor molecules. since vg has been previously detected in r. prolixus male adults, protein synthesis by fat bodies from 5th instar male nymphs was investigated and no vg synthesis could be detected. also, a 6.1 kb rna is present in female adults but not in 5th instar male nymphs. therefore, cdnas from female adult and 5th instar ma ... | 1993 | 8508188 |
| reversible binding of nitric oxide by a salivary heme protein from a bloodsucking insect. | the bloodsucking bug rhodnius prolixus has a salivary vasodilator, previously characterized as a nitrovasodilator, with salivary smooth muscle-relaxing and antiplatelet activity. rhodnius salivary glands are bright red owing to the abundance of heme proteins. electron paramagnetic resonance and optical spectroscopic experiments indicated that the salivary vasodilator is a nitrosylheme protein with an fe(iii) heme that binds nitric oxide (no) reversibly. dilution of the protein in neutral ph prom ... | 1993 | 8386393 |
| the regulation of haemolymph potassium activity during initiation and maintenance of diuresis in fed rhodnius prolixus. | the blood-sucking insect rhodnius prolixus rapidly eliminates a na(+)-rich k(+)-poor urine after its large meals. k(+)-rich fluid is first secreted by the upper malpighian tubules and passes to the lower tubules where most of the potassium is reabsorbed. during the initial stimulation of the tubules, the lower tubules must be activated first to avoid loss of potassium. the major element in this is that they respond more rapidly than do the upper tubules to particular hormonal concentrations rath ... | 1993 | 8486999 |
| ionic basis of bioelectric currents during oogenesis in an insect. | transmembrane bioelectric currents around insect ovaries are well documented but as yet poorly understood. in the present study we describe the ionic basis of such currents around the telotrophic ovariole of rhodnius prolixus using a two-dimensional vibrating probe and ion-substituted media and inhibitors. current efflux from the base and apex of the terminal follicle is carried by electrogenic na+ transport, and the return circuit over the middle of the terminal follicle is the result of na+ in ... | 1993 | 7688328 |
| protein phosphorylation in rhodnius prolixus oocytes: identification of a type ii casein kinase. | a protein kinase activity in chorionated oocytes of rhodnius prolixus phosphorylates in vitro vitellin (vt), the major yolk protein. phosphatase inhibitors including naf, sodium vanadate, beta-glycerophosphate and okadaic acid did not alter the protein phosphorylation profile to a visible extent. among the exogenous protein substrates tested, casein was readily phosphorylated, but histones were not. several different protein kinase activators, including camp, ca2+ plus calmodulin, ca2+ plus diol ... | 1993 | 11446384 |
| nitric oxide synthase activity from a hematophagous insect salivary gland. | the salivary glands of the hematophagous insect, rhodnius prolixus, contain a nitrosylhemeprotein that dissociates its ligand, no, to the host tissues while the insect is searching for a blood meal. we now report a salivary nitric oxide synthase activity in this insect. the activity is dependent on nadph, fad, tetrahydrobiopterin, calmodulin, ca2+, and converts arginine to citrulline while producing vasorelaxing activity. molecular sieving indicates a molecular weight of 185 kda, coeluting with ... | 1993 | 7689981 |
| [comparative study of the susceptibility of 5 triatomine species (insecta: reduviidae) to trypanosoma cruzi infection]. | in order to determine the most suitable species of triatomine for xenodiagnosis of the chagas disease, five species triatomine (triatoma barberi, t. infestans, t. pallidipennis, t. phyllosoma, and rhodnius prolixus) in third and fourth instars were used to evaluate their susceptibility to one t. cruzi strain isolated in mexico. the susceptibility was determined by: a) percentage of infected triatomines, b) amount of flagellates in bug feces and c) amount of blood ingested. we found that in most ... | 1993 | 8209115 |
| use of the median process of the pygophore in the identification of rhodnius nasutus, r. neglectus, r. prolixus and r. robustus (hemiptera: reduviidae). | the morphometrics of the median process of the male pygophore of four species of blood-sucking bugs (rhodnius prolixus, r. robustus, r. nasutus and r. neglectus) were compared using one-way analysis of variance. although there were no significant differences in the pygophoral patterns within the r. nasutus-r. neglectus or r. prolixus-r. robustus species pairs, there were clear-cut differences between them; the median process of r. nasutus-r. neglectus is stout and subtriangular whereas that of r ... | 1993 | 8257239 |
| a kazal-type inhibitor with thrombin specificity from rhodnius prolixus. | a thrombin-specific inhibitor with an apparent molecular mass of 11 kda has been purified from the insect rhodnius prolixus. amino-terminal protein sequence analysis allowed the molecular cloning of the corresponding cdna. the open reading frame codes for a protein of about 103 amino acid residues and displays an internal sequence homology of residues 6-48 with residues 57-101 indicating a two-domain structure. based on the amino acid sequence the two domains exhibit high homology to protease in ... | 1993 | 8344906 |
| rhodnius prolixus: salivary antihemostatic components decrease with trypanosoma rangeli infection. | feeding behavior and some antihemostatic properties of the saliva of rhodnius prolixus infected with trypanosoma rangeli were studied and compared with those of uninfected controls. insects with salivary gland infection pierced host skin more often and drew less blood and at a lower rate than controls when feeding on a rabbit. none of these differences was observed when feeding was performed through a membrane feeder. salivary gland homogenates from infected insects, at 30 days after feeding/inf ... | 1994 | 8162960 |
| structural specialization in the flagellum of the spermatozoon of the bloodsucking bug (rhodnius prolixus; hemiptera, reduviidae). | spermatozoa of the triatomideo rhodnius prolixus possess an axoneme with a 9 + 9 + 2 microtubule pattern and two mitochondrial derivatives. bridges occur between axoneme and mitochondrial derivatives. two paracrystalline structures embedded in amorphous regions were observed in the mitochondrial derivative. the use of the negative staining technique shows a zig-zag profile in the mitochondrial derivatives due to infolding to the cristae, regularly spaced with approximately 50 nm. this spacing is ... | 1994 | 8073413 |
| morphometric variability in the chagas' disease vector rhodnius prolixus. | morphometric variability was studied in six domestic venezuelan populations of the blood-sucking bug rhodnius prolixus stal 1897 (reduviidae, triatominae) and in a sylvatic population identified as r. robustus larrousse 1927. evidence is here provided by both uni- and multifactorial analyses of extensive variation of morphological traits between the r. prolixus populations studied. regardless the geographic or climatic environmental factor tested, none can be retained in a selective model accoun ... | 1994 | 8080655 |
| trypanosoma cruzi: metacyclogenesis in vitro--i. changes in the properties of metacyclic trypomastigotes maintained in the laboratory by different methods. | in this work we have studied the modifications in the biological properties of trypanosoma cruzi when the parasite is maintained for a long time in axenic culture. the studies were done with a clone from an avirulent strain (dm30l) and a non-cloned virulent strain (ep) of t. cruzi. both parasites were maintained, for at least three years, by successive triatomine/mouse alternate passage (control condition), or by serial passage in axenic medium (culture condition), or only in the mouse (mouse co ... | 1994 | 7885254 |
| a kazal-type inhibitor of human mast cell tryptase: isolation from the medical leech hirudo medicinalis, characterization, and sequence analysis. | human tryptase, a tetrameric proteinase expressed by mast cells, is virtually unique among the serine proteinases as it is not inhibited by any proteinaceous inhibitor tested so far. we have now isolated, sequenced, and characterized an inhibitor of human tryptase from the medical leech hirudo medicinalis. ldti (leech-derived tryptase inhibitor) was purified to apparent homogeneity by cation exchange and affinity chromatography. amino acid sequencing of the protein consisting of 46 residues (m(r ... | 1994 | 7888081 |
| high affinity histamine-binding and antihistaminic activity of the salivary nitric oxide-carrying heme protein (nitrophorin) of rhodnius prolixus. | the salivary glands of rhodnius prolixus contain a nitrosyl-heme protein, named nitrophorin, that releases the vasodilatory and antiplatelet compound nitric oxide (no). because imidazole compounds such as histamine can interact with fe(iii) heme proteins, we investigated whether such substances could interact with rhodnius nitrophorins. both imidazole and histamine, but not histidine can produce full of the difference spectra of the soret band in the 1-3 microm concentration range (at a heme pro ... | 1994 | 7964498 |
| randomly amplified polymorphic dna (rapd) and isoenzyme analysis of trypanosoma rangeli strains. | sixteen trypanosoma rangeli strains were compared by isoenzyme and randomly amplified polymorphic dna (rapd) analysis. eight strains were isolated from either rhodnius prolixus or homo sapiens from honduras, colombia and venezuela. another eight strains were isolated from either panstrongylus megistus or the rodent echimys dasythrix from the state of santa catarina, southern brazil. all six t. rangeli strains isolated from p. megistus were co-infections with trypanosoma cruzi, demonstrating an o ... | 1994 | 8049688 |
| immunogold labelling of serotonin-like and fmrfamide-like immunoreactive material in neurohaemal areas on abdominal nerves of rhodnius prolixus. | the ultrastructure of neurohaemal areas on abdominal nerves of the blood-sucking bug rhodnius prolixus was investigated. four types of axon terminals were found, distinguished by the morphology of their neurosecretory granules. by use of post-embedding immunogold labelling, granules in type i axon terminals were shown to contain serotonin-like immunoreactive material, and granules in type ii axon terminals were shown to contain fmrfamide-like immunoreactive material. there was no colocalization ... | 1994 | 7954695 |
| 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 |
| 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 |
| a heme-binding protein from hemolymph and oocytes of the blood-sucking insect, rhodnius prolixus. isolation and characterization. | a heme-binding protein has been isolated and characterized from both the hemolymph and oocytes of the blood-sucking insect, rhodnius prolixus. the protein from both sources is identical in most aspects studied. the rhodnius heme-binding protein (rhbp) is composed of a single 15-kda polypeptide chain coiled in a highly alpha-helical structure which binds non-covalently one heme/polypeptide chain. this rhbp is not produced by limited degradation of hemoglobin from the vertebrate host, since specif ... | 1995 | 7738030 |
| trypanosoma cruzi and trypanosoma rangeli: interplay with hemolymph components of rhodnius prolixus. | studies were carried out on the course of infection of trypanosoma cruzi (clone dm28c) and trypanosoma rangeli (clone san agustin) and their interactions with hemolymph components of rhodnius prolixus. these parasites when inoculated into the hemocoel of adult r. prolixus (i) had different courses of infection (t. rangeli had high rates of both multiplication and infection and t. cruzi had no division and disappeared soon from the hemolymph); (ii) induced high but no differential increases in ly ... | 1995 | 7745280 |
| 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 |
| induction of trypanosoma cruzi metacyclogenesis in the gut of the hematophagous insect vector, rhodnius prolixus, by hemoglobin and peptides carrying alpha d-globin sequences. | trypanosoma cruzi, a protozoan responsible for the american trypanosomiasis (chagas disease), multiplies and differentiates in the gut of triatomine insect vectors. the effects of hemoglobin and synthetic peptides carrying alpha d-globin fragments on both the growth and the transformation of t. cruzi epimastigotes (noninfective) into metacyclic trypmastigotes (infective forms) were studied. this differentiation in the insect's gut is expressed when hemoglobin and synthetic peptides corresponding ... | 1995 | 7498422 |
| density estimates of the domestic vector of chagas disease, rhodnius prolixus stål (hemiptera: reduviidae), in rural houses in venezuela. | we reported the use of the timed manual method, routinely employed as an indicator to the relative abundance of domestic triatomine bugs, to estimate their absolute density in houses. a team of six people collected rhodnius prolixus stål bugs from the walls and roofs of 14 typical palm-leaf rural houses located in cojedes, venezuela, spending 40 minutes searching in each house. one day after these manual collections, all the houses were demolished and the number of triatomine bugs were identifie ... | 1995 | 7614667 |
| a salivary nitrophorin (nitric-oxide-carrying hemoprotein) in the bedbug cimex lectularius. | salivary gland homogenate of the bedbug cimex lectularius caused vasodilation of the preconstricted rabbit aortic ring in the absence of endothelium. vasodilation was augmented in the presence of superoxide dismutase and inhibited in the presence of methylene blue. utilization of the griess reaction indicated the presence of reactive nitrogen equivalents of the order of 337 +/- 57 pg equivalent no2- per pair of salivary glands (mean +/- s.e.m.; n = 3). salivary gland homogenates have a nitrosyl- ... | 1995 | 7658188 |
| 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 |
| genetic variability and differentiation between populations of rhodnius prolixus and r. pallescens, vectors of chagas' disease in colombia. | enzyme polymorphism in rhodnius prolixus and r. pallescens (hemiptera, reduviidae), principal vectors of chagas' disease in colombia, was analyzed using starch gel electrophoresis. three geographic locations were sampled in order to determine gene flow between populations and to characterize intra- and interspecific differences. of 25 enzymes assayed 10 were successfully resolved and then used to score the genetic variation. the enzymes pepd, gpi, pgm and icd were useful to differentiate these s ... | 1995 | 8544739 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 | |
| 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 |