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effect of sublethal dosages of malathion on the oral susceptibility of aedes aegypti to dengue-2 virus infection. 19979561626
plasmodium gallinaceum: effect of insect cells on ookinete development in vitro.in vitro culture conditions affecting the transformation efficiency from zygote to ookinete for plasmodium gallinaceum were examined, as a step toward improving the overall efficiency of in vitro culture systems for sporogonic stages. gametocytes from infected chickens were allowed to fertilize in vitro and the resulting zygotes were purified and cultured. the time course for ookinete development in vitro was similar to that seen in aedes aegypti mosquitoes. supplementing a basal m-199 culture m ...19989562424
germination, growth, and sporulation of bacillus thuringiensis subsp. israelensis in excreted food vacuoles of the protozoan tetrahymena pyriformis.spores of bacillus thuringiensis subsp. israelensis and their toxic crystals are bioencapsulated in the protozoan tetrahymena pyriformis, in which the toxin remains stable. each t. pyriformis cell concentrates the spores and crystals in its food vacuoles, thus delivering them to mosquito larvae, which rapidly die. vacuoles containing undigested material are later excreted from the cells. the fate of spores and toxin inside the food vacuoles was determined at various times after excretion by phas ...19989572947
involvement of superoxide dismutase in spore coat assembly in bacillus subtilis.endospores of bacillus subtilis are enclosed in a proteinaceous coat which can be differentiated into a thick, striated outer layer and a thinner, lamellar inner layer. we found that the n-terminal sequence of a 25-kda protein present in a preparation of spore coat proteins matched that of the mn-dependent superoxide dismutase (sod) encoded by the sod4 locus. sod4 is transcribed throughout the growth and sporulation of a wild-type strain and is responsible for the sod activity detected in total ...19989573176
the ultraspiracle gene of the spruce budworm, choristoneura fumiferana: cloning of cdna and developmental expression of mrna.cloning and characterization of a choristoneura fumiferana ultraspiracle (cfusp) cdna are described. first, a pcr fragment and then a cdna clone (4.4 kb) were isolated from spruce budworm cdna libraries. comparison of the deduced amino acid sequence of this cdna with the sequences in genbank showed that this sequence had high homology with the ultraspiracle cdnas cloned from drosophila melanogaster (dmusp), bombyx mori (bmusp), manduca sexta (msusp), and aedes aegypti (aausp). the cfusp cdna con ...19989581288
adherence of erythrocytes during exflagellation of plasmodium falciparum microgametes is dependent on erythrocyte surface sialic acid and glycophorins.malaria male gametocytes within a newly ingested infected blood meal in the mosquito midgut emerge from erythrocytes and extrude approximately eight flagellar microgametes in a process termed exflagellation. in culture, and in blood removed from infected patients, emerging microgametes avidly adhere to neighboring uninfected and infected erythrocytes, as well as to emerged female macrogametes, creating "exflagellation centers". the mechanism of erythrocyte adherence is not known nor has it been ...19989584138
effects on larvicidal activity of single proline substitutions in alpha3 or alpha4 of the bacillus thuringiensis cry4b toxin.the possible role of alpha-helices 3 and 4 in toxicity of the dipteran-active bacillus thuringiensis cry4b delta-endotoxin was investigated by employing proline substitutions via site-directed mutagenesis. similar to the wild-type cry4b, the mutant toxins were over-expressed in escherichia coli as cytoplasmic inclusions and were structurally stable upon solubilization and trypsin activation. the substitution of glutamine 149 by proline in the center of helix 4 (q149p) resulted in a nearly comple ...19989584996
monitoring of dengue viruses in field-caught aedes aegypti and aedes albopictus mosquitoes by a type-specific polymerase chain reaction and cycle sequencing.virologic surveillance for dengue through the detection of the prevalent serotype(s) circulating in the human population during inter- and intra-epidemic periods constitutes a reliable sentinel system for dengue outbreaks. we have applied a rapid and sensitive, semi-nested, reverse transcription-polymerase chain reaction (rt-pcr) assay using nonstructural protein 3 gene primers for the type-specific-detection of dengue viruses in artificially infected and in field-caught adult aedes mosquitoes. ...19989598444
engineered resistance in aedes aegypti to a west african and a south american strain of yellow fever virus.double subgenomic sindbis (dssin) viruses were engineered to transduce mosquito cells with antisense rna derived either from the premembrane (prm) or polymerase (ns5) coding regions of the 17d vaccine strain of yellow fever virus (yfv). aedes albopictus c6/36 cells were infected at high multiplicities of infection (moi) with each dssin virus. forty-eight hours later, the transduced cells were challenged with an moi of 0.1 of the asibi strain of yfv. at 72-hr postchallenge, the cells were assayed ...19989598458
laboratory bioassay to compare susceptibilities of aedes aegypti and anopheles albimanus to bacillus thuringiensis var. israelensis as affected by their feeding rates.this study presents the effect of differences in the feeding rates of aedes aegypti and anopheles albimanus on their susceptibilities to bacillus thuringiensis israelensis. aedes aegypti was more susceptible than an. albimanus because of its faster rate of feeding. aedes aegypti ingested 11.5 times more spores than did an. albimanus, resulting in lower lt50 values. anopheles albimanus larvae fed at a slower rate and required fewer spores than ae. aegypti to induce 50% mortality. these findings s ...19989599326
plasmodium gallinaceum: differential killing of some mosquito stages of the parasite by insect defensin.we examined several insect antimicrobial peptides to study their effect on plasmodium gallinaceum zygotes, ookinetes, oocysts, and sporozoites. only two insect defensins-aeschna cyanea (dragon fly) and phormia terranovae (flesh fly)-had a profound toxic effect on the oocysts in aedes aegypti and on isolated sporozoites. the defensins affected the oocysts in a time-dependent manner. injecting the peptide into the hemolymph 1 or 2 days after an infectious blood meal had no significant effect on pr ...19989603495
clinical evaluation of a rapid immunochromatographic test for the diagnosis of dengue virus infection.a rapid immunochromatographic test was compared to the hemagglutination inhibition assay for separate determinations of dengue virus-specific immunoglobulin m (igm) and igg levels in paired serum specimens from 92 patients (34 with primary dengue virus infection, 35 with secondary dengue virus infection, and 23 without dengue virus infection). the rapid test showed 99% sensitivity in the diagnosis of dengue virus infection. the majority (30 of 34 [88%]) of patients with primary infection showed ...19989606000
carboxypeptidase b in anopheles gambiae (diptera: culicidae): effects of abdominal distention and blood ingestion.carboxypeptidase b (cpb) activity was detected in the guts of strain g-3 of anopheles gambiae (giles) and aedes aegypti (l.). mosquitoes were examined 3-5 d after emergence following exposure to 20% sucrose, from 0 to 4 h after feeding on a meal of latex beads in saline, and from 0 to 96 h after blood feeding. cpb activity was assayed in whole-gut homogenates, including lumenal contents and peritrophic matrix, by following the hydrolysis of a substrate specific for cpb-[3h]-benzoyl-l-phe-l-arg. ...19989615537
cytotoxic and insecticidal constituents of the unripe fruit of persea americana.unripe avocado fruit (persea americana) was subjected to a bioactivity-directed fractionation, as monitored via the brine shrimp lethality assay, to isolate three major bioactive constituents (1-3). compounds 1-3 all have a 1,2,4-triol moiety and a long aliphatic chain that terminates as either an alkane, alkene, or alkyne, respectively; 1 is new, while 2 and 3 have been described previously but not as cytotoxic or pesticidal agents. all have activity against six human tumor cell lines in cultur ...19989644064
detection of japanese encephalitis virus by reverse transcription/polymerase chain reaction.a simple and rapid reverse transcription/polymerase chain reaction (rt-pcr) assay for detection of japanese encephalitis virus (jev) envelope (e) gene sequences in various biological samples is described. the assay successfully amplified jev e gene sequences from infected cell cultures, aedes aegypti larvae, mosquitoes and mouse blood. the sensitivity of the assay was currently 1 ng of jev rna and could be increased up to 1 pg on the background of 1 microgram of cellular rna by biotinylation of ...19989645237
insecticidal activity of bacillus laterosporus.the bacillus laterosporus strains 921 and 615 were shown to have toxicity for larvae of the mosquitoes aedes aegypti, anopheles stephensi, and culex pipiens. the larvicidal activity of b. laterosporus was associated with spores and crystalline inclusions. purified b. laterosporus 615 crystals were highly toxic for aedes aegypti and anopheles stephensi.19989647857
breeding habitats of aedes aegypti (l) and aedes. albopictus (skuse) in villages of barru, south sulawesi, indonesia.the breeding habitats of the dengue vector, aedes aegypti and aedes albopictus, were studied using larval collection method inside and outside houses in 6 villages of barru, south sulawesi, indonesia from july 1994 to august 1995. aedes aegypti was the dominant species, being abundant indoors especially in the coastal areas. aedes albopictus was breeding primarily in outdoor containers in the hill and mountain areas. earthen jar was the most common breeding habitat of aedes aegypti in all villag ...19979656413
identification of immune-related protein kinases from mosquitoes (aedes aegypti).protein kinases are known to be involved in signal transduction for numerous physiological events. however, little is known about the roles of protein kinases in insect immunity. a fragment around 150 bp was amplified by polymerase chain reaction using cdna templates from bacterial inoculated mosquitoes and primers corresponding to the conserved domain of protein kinases. based on sequence analysis, 11 groups of protein kinases were characterized including 3 nonreceptor tyrosine kinases, 3 recep ...19989662071
chitinases are a multi-gene family in aedes, anopheles and drosophila.degenerate primers were used to amplify by the polymerase chain reaction (pcr) dna fragments from the chitinase genes of five insect species: aedes aegypti, anopheles freeborni, anopheles gambiae, anopheles stephensi and drosophila melanogaster. as many as four different products were found for each species; each deduced protein sequence having greatest homology to chitinase sequences from other species of insects and the crustacean, penaeus japonicus. the four pcr products of a. aegypti hybridi ...19989662472
dengue and dengue hemorrhagic fever.dengue fever, a very old disease, has reemerged in the past 20 years with an expanded geographic distribution of both the viruses and the mosquito vectors, increased epidemic activity, the development of hyperendemicity (the cocirculation of multiple serotypes), and the emergence of dengue hemorrhagic fever in new geographic regions. in 1998 this mosquito-borne disease is the most important tropical infectious disease after malaria, with an estimated 100 million cases of dengue fever, 500,000 ca ...19989665979
a comparison of surveillance systems for the dengue vector aedes aegypti in port of spain, trinidad.when the currently used larval surveillance system (visual inspection) for the dengue vector aedes aegypti was compared with the surveillance for the presence of eggs by ovitrapping in port of spain, trinidad, it was found that the latter (39.1%) was significantly more sensitive than the visual inspection system (10.1%). at the same time, the presence of the nuisance mosquito culex quinquefasciatus was detected in 38.4% of the households. both ae. aegypti and cx. quinquefasciatus showed preferen ...19989673912
effect of female size on fecundity and survivorship of aedes aegypti fed only human blood versus human blood plus sugar.we determined whether size, an indirect measure of teneral energy reserves, modifies the fitness advantage (sigma survival x egg production/female/day) conferred to female aedes aegypti (l.) maintained on human blood over cohorts fed human blood plus sugar. different sized females were obtained by rearing them at different larval densities and with different amounts of food per larva. each female in 4 treatment groups of 23 mosquitoes each was maintained in a separate cage. a 10% sucrose solutio ...19989673914
effect of skin abrasions on the efficacy of the repellent deet against aedes aegypti.abrasion of repellent-treated human skin affected the efficacy of a sustained-release insect repellent containing n,n-diethyl-3-methylbenzamide (deet) against bites of aedes aegypti. skin treated with repellent when abraded up to 30 times showed significantly lower protection than unabraded skin against mosquito bites for 10 h. the mean value of the kinetic coefficient of friction during skin abrasion by clothing (battle dress uniform fabric) for repellent-treated skin (0.159 +/- 0.003) was sign ...19989673919
field evaluation of cyfluthrin and malathion 96 tg ulv spraying at high-rise flats on dengue vectors in malaysia.cyfluthrin (solfac ulo15) and malathion 96 tg were evaluated against sentinel sugar-fed adults and 4th-instar larvae of aedes aegypti at high-rise flats in malaysia by ulv spraying. the impact of both insecticides on field populations of aedes spp. (ae. aegypti and ae. albopictus) larvae were monitored weekly using containers. both cyfluthrin and malathion 96 tg showed adulticidal effects but cyfluthrin showed more significant larvicidal effect than malathion 96 tg (p < 0.05).19989673932
re-emergence of yellow fever in senegal in 1995.an outbreak of yellow fever (yf) occurred in the central part of senegal during october 1995. thirty-one probable cases were detected and 79 cases were confirmed either by igm elisa or by virus isolation (30 strains isolated). the case fatality rate was 18.9%. incidence of the infection was evaluated by a serosurvey in the area. males 10-29 years old belonging to the peul ethnic group were more affected. moreover, 28 yf virus strains were isolated from mosquitoes and larvae pools and vertical tr ...19989684637
[dengue in panama, 1993].up to 1993, panama was the only country in central america where the autochthonous transmission of dengue virus had been detected without experimenting an explosive epidemic despite being reinfected with the aedes aegypti mosquito since 1985. the characteristics of this first outbreak reported on november 19, 1993, are described in this paper. it is shown that even when there is a program for the surveillance and control of dengue, which considers low levels of aedes aegypti infection and a syst ...19979685969
a mouse model of mosquito allergy for study of antigen-specific ige and igg subclass responses, lymphocyte proliferation, and il-4 and ifn-gamma production.to date, there are no ideal animal models for study of natural sensitization leading to ige- and lymphocyte-mediated hypersensitivities. we established such a model in which four balb/c mice were each sensitized by exposure to at least 16 mosquito aedes aegypti bites, twice a week for 4 weeks. four non-exposed control mice were also studied. mosquito a. aegypti head and thorax extract, saliva, and two recombinant salivary allergens (raed a 1 and raed a 2) were used in vitro as antigens. intrader ...19989693276
coevolutionary interactions between host life histories and parasite life cycles.several recent studies have discussed the interaction of host life-history traits and parasite life cycles. it has been observed that the life-history of a host often changes after infection by a parasite. in some cases, changes of host life-history traits reduce the costs of parasitism and can be interpreted as a form of resistance against the parasite. in other cases, changes of host life-history traits increase the parasite's transmission and can be interpreted as manipulation by the parasite ...19989695109
trial of a community-based intervention to decrease infestation of aedes aegypti mosquitoes in cement washbasins in el progreso, honduras.washbasins and metal drums are important sources of aedes aegypti mosquitoes in much of latin america. when manual cleaning was found to be ineffective in eliminating mosquito larvae in a community-based control programme in el progreso, honduras, it was decided to develop and evaluate an improved method of removing mosquito eggs based on commonly-available materials. the method, named la untadita ('the little dab', in english), consists of five steps: mixing chlorine bleach and detergent to mak ...19989698263
dengue control in ribeirão preto, são paulo, brazil.following an epidemic of type i dengue in late 1990, the municipality of ribeirão preto (state of são paulo, brazil) assumed direct responsibility for the control of aedes aegypti larvae. control activities are presented in this report and are based on popular participation in environmental management. massive use of the communications media, participation by schoolchildren, constant contact with the population, and integration of various public agencies are the program's priorities. although th ...19989700231
predation on aedes aegypti (diptera: culicidae) by theridion rufipes (araneae: theridiidae) in puerto rico.theridion rufipes lucas was found in rearing cages of aedes aegypti (l.) in the school of medicine, san juan, pr. from the 1970s to the 1990s, the spiders had a continuous existence in the cages and in the room outside the cages. a single spider eventually could eliminate all the mosquitoes in a cage. the behavior of the mosquitoes in the web was observed by isolating spiders individually in glass or plastic flasks. when a mosquito comes in contact with the beads of sticky silk on the web, it is ...19989701953
typing of dengue viruses in clinical specimens and mosquitoes by single-tube multiplex reverse transcriptase pcr.in recent years, dengue viruses (serotypes 1 to 4) have spread throughout tropical regions worldwide. in many places, multiple dengue virus serotypes are circulating concurrently, which may increase the risk for the more severe form of the disease, dengue hemorrhagic fever. for the control and prevention of dengue fever, it is important to rapidly detect and type the virus in clinical samples and mosquitoes. assays based on reverse transcriptase (rt) pcr (rt-pcr) amplification of dengue viral rn ...19989705406
multiple host-feeding and biting persistence of aedes aegypti.the effects of host activity, host defensive behaviour and biting persistence on multiple host-feeding by aedes aegypti (l.) were investigated, in laboratory conditions, on human volunteers. in four different settings, four or five volunteer hosts displayed inactive, mildly active, mildly defensive and highly defensive behaviour. into each of the four trials, each with 20 replicates, a single mosquito was released for a period of 10 min. in all settings, the median number of hosts sought per mos ...19989713547
development of an indicator to evaluate the impact, on a community-based aedes aegypti control intervention, of improved cleaning of water-storage containers by householders.householders in a community-based programme to control dengue in el progreso, honduras, are being encouraged to improve the cleaning of the water-storage containers in which many of the vectors thrive. the objective of the present study was to develop an indicator of the change occurring in human behaviour. traditional aedes aegypti larval indices do not differentiate between containers in which all the immature stages are present and those which hold only first- and second-instar larvae. howeve ...19989713548
antibody to a cdna-derived calreticulin protein from amblyomma americanum as a biomarker of tick exposure in humans.the antibody responses of human and animal hosts were studied to determine the utility of antibody against recombinant tick calreticulin (rtc), a cdna-derived protein isolated from salivary glands of amblyomma americanum l., as a biologic marker of tick exposure. rabbits fed upon by either a. americanum or dermacentor variabilis say developed significant anti-rtc antibody responses, as measured by both elisa and immunoblot assay. in contrast, gerbils exposed to aedes aegypti did not develop anti ...19989715947
bacillus thuringiensis and its pesticidal crystal proteins.during the past decade the pesticidal bacterium bacillus thuringiensis has been the subject of intensive research. these efforts have yielded considerable data about the complex relationships between the structure, mechanism of action, and genetics of the organism's pesticidal crystal proteins, and a coherent picture of these relationships is beginning to emerge. other studies have focused on the ecological role of the b. thuringiensis crystal proteins, their performance in agricultural and othe ...19989729609
determination of dengue virus serotypes in individual aedes aegypti mosquitoes in colombia.adult aedes aegypti mosquitoes were collected in puerto triunfo, central colombia, where dengue is endemic, during a six month period. viral infection within the head of each individual mosquito was identified by an immunofluorescent assay (ifa) using a flavivirus-specific monoclonal antibody. the dengue virus serotype, present in each flavivirus-positive specimen, was then determined in portions of the remaining thorax using ifas with serotype-specific monoclonal antibodies. among 2065 female a ...19989737600
comparative repellency of commercial formulations of deet, permethrin and citronellal against the mosquito aedes aegypti, using a collagen membrane technique compared with human arm tests.a collagen membrane technique, based on the membrane blood-feeding system of cosgrove et al. (1994), was used to compare repellents against aedes aegypti mosquitoes. repellency was defined in terms of inhibition of probing (ed50 and ed90) after 5 min exposure. a direct comparison was made with repellency from probing after 5 min on five male volunteers. four repellent products were compared with technical deet as the standard. the liquid formulations tested were: autan (20% deet; bayer); repel p ...19989737601
thanaka (limonia acidissima) and deet (di-methyl benzamide) mixture as a mosquito repellent for use by karen women.the prevention and treatment of drug-resistant malaria is becoming increasingly difficult. on the thai-myanmar border multi-drug resistant strains of falciparum malaria are increasing and, because the malaria vector anopheles bite outdoors during early evening, insecticide house-spraying or impregnated bednets provide only limited protection. therefore, the protective efficacy of repellent formulations containing di-methyl benzamide (deet) and permethrin against local vectors was estimated, when ...19989737602
biochemical monitoring of organophosphorus and carbamate insecticide resistance in aedes aegypti mosquitoes from trinidad. 19989737606
distribution of potential dengue vectors in major townships along the national highways and trunk roads of northeast india.surveys were conducted in some townships along the national highways and trunk roads of northeast india to detect breeding of aedes mosquitos in used/waste tire dumps piled outdoors by the tire repairing shops during summer season of 1996-1997. the breeding of both the potential vectors of dengue, viz. aedes aegypti and ae. albopictus were detected, prevalence rate being in the range of 30.0-88.0 (ci = container index value). the preponderance of ae. aegypti was considerably much higher than tha ...19989740295
similarities to a line element shared by anopheline and culicine mosquitos map to the distal end of dihydrofolate reductase amplicons in aedes albopictus mosquito cells.to extend our understanding of amplicon structure in methotrexate-resistant mtx-5011-256 aedes albopictus mosquito cells, we examined a series of cosmids containing genomic dna corresponding to the unique 3'-end of the type 1 dihydrofolate reductase amplicon. cosmid pwed118 contained five ecori fragments ranging from 2 to 5 kb (a, b, c, f, g) that hybridized to cdna from methotrexate-resistant cells. of these, fragments b and f hybridized weakly to first-strand cdna from sensitive cells and shar ...19989753771
the introduction into bacillus sphaericus of the bacillus thuringiensis subsp. medellin cyt1ab1 gene results in higher susceptibility of resistant mosquito larva populations to b. sphaericus.the fragment containing the gene encoding the cytolytic cyt1ab1 protein from bacillus thuringiensis subsp. medellin and its flanking sequences (i. thiery, a. delécluse, m. c. tamayo, and s. orduz, appl. environ. microbiol. 63:468-473, 1997) was introduced into bacillus sphaericus toxic strains 2362, 2297, and iab872 by electroporation with the shuttle vector pmk3. only small amounts of the protein were produced in recombinant strains 2362 and iab872. the protein was detected in these strains onl ...19989758818
sequence of the cry11bb11 gene from bacillus thuringiensis subsp. medellin and toxicity analysis of its encoded protein.the nucleotide sequence of the cry11bb1 gene from bacillus thuringiensis subsp. medellin was determined. the corresponding protein has a deduced molecular mass of 88.2 kda, and is 60.9% and 83% identical to the proteins cry11aa1 and cry11ba1, respectively. the cry11bb1 protein contains five repetitive blocks of 16 amino acids at the c terminal part. it is highly toxic to first instar laboratory reared aedes aegypti, anopheles albimanus and culex quinquefasciatus larvae.19989774743
field evaluation of mesocyclops longisetus (copepoda: cyclopoidea) for the control of larval aedes aegypti (diptera culicidae) in northeastern mexico.field trials of the predacious copepod mesocyclops longisetus thiubaud were conducted in northeastern mexico to determine the effectiveness of this species to control larval aedes aegypti (l.) populations and to survive and reproduce in nature. groups of 200, 50, and 50 ovigerous m. longisetus females were inoculated into 200-liter metal drums, discarded tires, and cemetery flower vases, respectively, which are 3 of the more important aedes breeding sites in this area. larvae were sampled at 15- ...19989775596
oviposition attraction and repellency of aedes aegypti (diptera: culicidae) to waters from conspecific larvae subjected to crowding, confinement, starvation, or infection.as the biomass of aedes aegypti (l.) larvae increased in relation to the volume of rearing waters, oviposition attraction of these waters to conspecific, gravid females first rose to a peak and then declined. further increases in biomass rendered waters strongly repellent. comparable responses were elicited by a decrease in the volume of rearing waters or an increase in the relative size or number of mosquito larvae. low volumes of water reduced oviposition attraction and increased repellency, w ...19989775609
life table study of aedes aegypti (diptera: culicidae) in puerto rico fed only human blood versus blood plus sugar.life table studies were performed in 1996 with aedes aegypti (l.) during the low (cool/dry) and high (hot/rainy) dengue virus transmission seasons in puerto rico. mated adult females from field-collected pupae were placed individually in cages and divided into 2 treatment groups: one was fed only human blood and the other human blood plus a 10% sucrose solution. survival and number of eggs laid were recorded daily for each female. during both seasons, age specific survivorship was higher for the ...19989775613
mono-tetrahydrofuran acetogenins from goniothalamus giganteus.goniotetracin and a mixture of (2,4-cis and trans)-gonioneninone, new, bioactive, mono-tetrahydrofuran (thf) gamma-lactone and ketolactone acetogenins, were isolated from the bark of goniothalamus giganteus (annonaceae) by activity-directed fractionation using the brine shrimp lethality test (bst). the structures were elucidated based on spectroscopic and chemical methods. their absolute stereochemistries were determined by the advanced mosher ester method. both showed selective and significant ...19989779595
adhesion of plasmodium gallinaceum ookinetes to the aedes aegypti midgut: sites of parasite attachment and morphological changes in the ookinete.plasmodium gallinaceum ookinetes adhered to aedes aegypti midgut epithelia when purified ookinetes and isolated midguts were combined in vitro. ookinetes preferentially bound to the microvillated luminal surface of the midgut, and they seemed to interact with three types of structures on the midgut surface. first, they adhered to and migrated through a network-like matrix, which we have termed microvilli-associated network, that covers the surface of the microvilli. this network forms on the lum ...19989783452
eradication of aedes aegypti from a village in vietnam, using copepods and community participation.in northern vietnam, copepods of the genus mesocyclops were used for biological control of aedes aegypti, the principal vector of dengue viruses, by inoculation into wells, large cement tanks, ceramic jars, and other domestic containers that served as ae. aegypti breeding sites. the use of mesocyclops was complemented by community participation with respect to recycling to eliminate unused and discarded containers that collected rainwater and provided ae. aegypti breeding sites that could not be ...19989790448
three isoforms of a hepatocyte nuclear factor-4 transcription factor with tissue- and stage-specific expression in the adult mosquito.we cloned three isoforms of hepatocyte nuclear factor-4 (hnf-4) from the mosquito aedes aegypti, designated aahnf-4a, aahnf-4b, and aahnf-4c. aahnf-4a and aahnf-4b are typical members of the hnf-4 subfamily of nuclear receptors with high amino acid conservation. they differ in n-terminal regions and exhibit distinct developmental profiles in the female mosquito fat body, a metabolic tissue functionally analogous to the vertebrate liver. the aahnf-4b mrna is predominant during the previtellogenic ...19989792695
variable cross-resistance to cry11b from bacillus thuringiensis subsp. jegathesan in culex quinquefasciatus (diptera: culicidae) resistant to single or multiple toxins of bacillus thuringiensis subsp. israelensis.a novel mosquitocidal bacterium, bacillus thuringiensis subsp. jegathesan, and one of its toxins, cry11b, in a recombinant b. thuringiensis strain were evaluated for cross-resistance with strains of the mosquito culex quinquefasciatus that are resistant to single and multiple toxins of bacillus thuringiensis subsp. israelensis. the levels of cross-resistance (resistance ratios [rr]) at concentrations which caused 95% mortality (lc95) between b. thuringiensis subsp. jegathesan and the different b ...19989797262
human dirofilariasis caused by dirofilaria (nochtiella) repens in sri lanka.human dirofilariasis due to dirofilaria (nochtiella) repens is a common zoonotic infection in sri lanka. todate 70 cases are on record, and they include 3 expatriates from russia, england and korea, who were undoubtedly infected in sri lanka. around 30-60% of dogs are infected with d. repens in various parts of the country and the mosquito vectors are aedes aegypti, armigeres subalbatus, mansonia uniformis and m. annulifera. unlike in other countries of the old world infection is most common in ...19979802095
[the performance of the aedes aegypti eradication program in 2 towns of ciudad de la habana province, 1990-1992].it is made a comparative analysis of the behaviour of the aedes aegypti eradication program in two municipalities of havana city with different characteristics during 1990-1992. the results show that in both municipalities the recipients with the highest positivity to mosquitoes were the following categories: other deposits, artificial deposits, and low tanks, followed by a second group that included tubs, tires, and larva tramps. the positivity of the larva tramps was observed in both municipal ...19969805046
[the effect of abiotic factors on the incidence of aedes aegypti in the town of 10 de octobre, ciudad de la habana province, 1982-1992].an analysis of the relation among the quantity of focuses of aedes aegypti, the rains and the temperatures in rainy and dry periods from 1982 to 1992 in 10 de octubre municipe, at city of havana, was carried out. no correlation was found between the number of focuses and the rains occurred in both seasons, and it was just the same between the number of focuses and temperatures. thus, emphasis is made in the need for a strong surveillance along all year.19959805076
an experimental study on the detection of fructose in aedes aegypti.male and female aedes aegypti fed a 10% sucrose solution and/or blood were tested to determine the duration of fructose detection in their bodies and the volume of sugar solution they ingested. the limit of detection of fructose by the cold anthrone test was investigated in a series of experiments. results were applied to the interpretation of sugar feeding by ae. aegypti collected inside houses in puerto rico during times of low (cool season) and high (hot season) dengue transmission in 1996. w ...19989813818
potency of products based on bacillus thuringiensis var. israelensis: interlaboratory variations.six quality-control laboratories in 4 countries independently bioassayed aliquots of a flowable formulation of bacillus thuringiensis var. israelensis (b.t.i.) against the international standard powder ips-82. all laboratories substantially followed world health organization or u.s. department of agriculture standard protocols. significant differences were found in resulting potency values between laboratories. factors that may have influenced results, such as age, stage, and strain of larvae us ...19989813828
dengue: a literature review and case study of travelers from the united states, 1986-1994.dengue fever is an acute, mosquito-transmitted viral disease characterized by fever, headache, arthralgia, myalgia, rash, nausea, and vomiting. infections are caused by any of four virus serotypes (den-1, den-2, den-3, and den-4). the incidence of dengue is increasing in most tropical areas throughout the world (fig. 1). although dengue is not endemic in the continental united states, hawaii, or alaska, more than 500 laboratory-positive cases of introduced dengue were reported from 1977 through ...19979815484
dengue outbreak associated with multiple serotypes--puerto rico, 1998.dengue is an acute viral disease caused by any of the four dengue virus serotypes (den-1, den-2, den-3, and den-4). the principal mosquito vector is aedes aegypti, which has a worldwide distribution in tropical and many subtropical areas. all four virus serotypes produce a similar illness characterized by fever, headache, myalgias, arthralgias, rash, nausea and vomiting and induce life-long immunity that is specific to the infecting serotype. a small proportion of infected persons may develop th ...19989832472
putative dengue virus receptors from mosquito cells.dengue viruses are arthropod-borne, single-stranded rna viruses. aëdes aegypti and aëdes albopictus are the principal vectors. in order to understand the molecular basis of dengue virus infections we explored the biochemical identity of dengue-2 (den-2) virus receptors in the aëdes albopictus-derived cell line c6/36. we show here that den-2 interacts with two major polypeptides of 80 and 67 kda. polyclonal anti-c6/36 membrane antibodies block den-2 binding to intact c6/36 monolayers as well as t ...19989835036
the genome of melanoplus sanguinipes entomopoxvirus.the family poxviridae contains two subfamilies: the entomopoxvirinae (poxviruses of insects) and the chordopoxvirinae (poxviruses of vertebrates). here we present the first characterization of the genome of an entomopoxvirus (epv) which infects the north american migratory grasshopper melanoplus sanguinipes and other important orthopteran pests. the 236-kbp m. sanguinipes epv (msepv) genome consists of a central coding region bounded by 7-kbp inverted terminal repeats and contains 267 open readi ...19999847359
determinants of dengue 2 infection among residents of charters towers, queensland, australia.dengue fever is caused by one of the four serotypes of the dengue virus and is transmitted by the urban mosquito aedes aegypti. in 1993, the city of charters towers in the tropical north of australia experienced an epidemic caused by the dengue 2 virus. a cross-sectional sample of 1,000 people was assessed for determinants of recent symptomatic dengue infection. after exclusion of people with prior exposure to dengue 2, a study group of 797 persons, including 196 patients with recent infection, ...19989850134
yellow fever outbreak in kaffrine, senegal 1996: epidemiological and entomological findings.in november 1996 a yellow fever (yf) outbreak occurred near kaffrine in the central part of senegal. thirty-six deaths were notified, all children under 15 years of age. the yf diagnosis was confirmed by mac-elisa or by virus isolation. the immune status against yf virus of a sample population of 449 individuals was determined, and 31 confirmed cases and 69 asymptomatic cases were reported. distribution of yf cases and incidence rate decreased with age, while the attack rate was stable in all ag ...19989855398
[indication and identification of california serogroup viruses in experimentally infected ae. aegypti mosquitos by a lanthanum immunofluorescent analysis method].the sensitivity and specificity of lanthanide fluoroimmunoassay (lfia) and enzyme immunoassay (eia) for indication and identification of california antigens in suspensions of infected aedes aegypti mosquitoes are compared. the sensitivity of lfia was 2.3 ig tcd50/ml, eia was less sensitive and detected virus antigens in mosquito suspensions at infective titer of 4.1 ig tcd50/ml. if a pool contained mosquitoes infected with different california viruses, they could be identified only at the level ...19989864828
molecular interactions between vestigial and scalloped promote wing formation in drosophila.scalloped (sd) and vestigial (vg) are each needed for drosophila wing development. we show that sd is required for vg function and that altering their relative cellular levels inhibits wing formation. in vitro, vg binds directly to both sd and its human homolog, transcription enhancer factor-1. the interaction domains map to a small region of vg that is essential for vg-mediated gene activation and to the carboxy-terminal half of sd. our observations indicate that vg and sd function coordinately ...19989869635
pathogenic action of penicillium species on mosquito vectors of human tropical diseases.in vitro bioassays were performed in order to assess the pathogenicity of 13 penicillium strains in 2nd stage larvae of aedes aegypti, aedes fluviatilis, anopheles aquasalis and culex quinquefasciatus. mortality rates began in the first 24 hours, ranging from 0 to 100%. p. corylophilum, p. fellutanum, p. implicatum, p. janthinellum, p. viridicatum and p. waksmanii species tested on aedes aegypti larvae and at different concentrations presented mortality rates from 0 to 6.6%. these species, when ...19989871331
isolation and characterization of brush border membrane vesicles from whole aedes aegypti larvae.studies of the binding interactions of dipteran-specific bacillus thuringiensis delta-endotoxins are hindered by the lengthy midgut dissection procedure needed for preparation of brush border membrane vesicles. in an attempt to resolve this problem, brush border membrane vesicles were isolated from homogenates of whole aedes aegypti larvae by a modification of the method of macintosh et al. (1994). these preparations were found to resolve well on sds-page and appeared as spherical vesicles of va ...19999878289
toxicity and receptor binding properties of a bacillus thuringiensis cryic toxin active against both lepidoptera and diptera.this study describes an investigation into the relationship among toxicity, specificity, and binding of cryic delta-endotoxin from bacillus thuringiensis subspecies aizawai hd-229. in vivo bioassays of larvae using inclusions (aedes aegypti) or solubilized toxin (spodoptera littoralis, spodoptera exigua, spodoptera frugiperda, and manduca sexta) revealed that cryic was toxic to both dipteran and lepidopteran larvae. in vitro saturation binding assays with cryic toxin labeled in vivo with [35s]me ...19999878290
[the aedes aegypti eradication program: useless, hazardous (and wasteful, in addition)]. 19989878922
olfactory responses and field attraction of mosquitoes to volatiles from limburger cheese and human foot odor.olfactory responses of female aedes aegypti (linnaeus) to various odor stimuli were studied in a dual-port olfactometer. responses (i.e., the percent of ca. 75 available female mosquitoes in flight chamber entering each olfactometer port) were studied toward clean conditioned air (control), human foot skin emanations (collected on socks by wearing them for three days), human hand, and limburger cheese. mean percent response was greatest to the human hand (80.1%), followed by the human worn sock ...19989879074
the effect of temperature and humidity on dengue virus propagation in aedes aegypti mosquitos.the effect of temperature and relative humidity on dengue virus propagation in the mosquito as one of the possible contributing factors to dengue hemorrhagic fever (dhf) outbreaks was studied. ae. aegypti mosquitos were reared under standard conditions and inoculated intrathoracically with dengue virus. virus propagation in the mosquitos was determined at the temperature and relative humidity of all 3 seasons of yangon and for the simulated temperature and relative humidity of singapore. the vir ...19989886113
quantitative genetics of vector competence for dengue-2 virus in aedes aegypti.a quantitative genetic study of the ability of aedes aegypti to propagate dengue-2 (den-2) virus in the midgut and in a disseminated infection in the head was conducted with a standard half-sib breeding design. aedes aegypti aegypti and a. aegypti formosus differ markedly in oral susceptibility to den-2 virus. mosquitoes were orally infected and, after an extrinsic incubation period of 14 days, virus titer (by tissue culture infectious dose, 50% endpoint) was determined in the midgut (mt) and he ...19989886207
pictorial key to the common indian species of aedes (stegomyia) mosquitoes.the paper provides a simple pictorial key to differentiate common stegomyia species found in urban areas. this key will help medical officers and paramedical staff in demarcating the areas of influence of aedes aegypti within a dengue surveillance area.19989914681
goniotriocin and (2,4-cis- and -trans)-xylomaticinones, bioactive annonaceous acetogenins from goniothalamus giganteus.goniotricin (1) and a mixture of (2,4-cis and -trans)-xylomaticinones (2), new bioactive annonaceous acetogenins, were isolated from the bark of goniothalamus giganteus (annonaceae) by activity-directed fractionation using the brine shrimp lethality test. compound 1 is the first nonadjacent ring-hydroxylated bis-tetrahydrofuran (thf) acetogenin to be reported. compound 2 is the cis- and trans-ketolactone mixture of xylomaticin, a known compound whose absolute stereochemistry has not been previou ...19999917277
mosquito-plasmodium interactions in response to immune activation of the vector.during the development of plasmodium sp. within the mosquito midgut, the parasite undergoes a series of developmental changes. the elongated ookinete migrates through the layers of the midgut where it forms the oocyst under the basal lamina. we demonstrate here that if aedes aegypti or anopheles gambiae, normally susceptible to plasmodium gallinaceum and p. berghei, respectively, are immune activated by the injection of bacteria into the hemocoel, and subsequently are fed on an infectious bloodm ...19999920043
analysis of human skin emanations by gas chromatography/mass spectrometry. 1. thermal desorption of attractants for the yellow fever mosquito (aedes aegypti) from handled glass beads.handled glass has the ability to collect and concentrate nonaqueous human skin emanations while minimizing the collection of aqueous perspiration. compounds originating from the skin and collected on glass have previously been found to attract the aedes aegypti species of mosquito. therefore, glass beads were used as the medium to collect skin emanations from humans for subsequent chemical analysis. this process consisted of a 5-15-min collection of sample on glass beads, followed by loading the ...19999921122
experimental infection of culex (culex) quinquefasciatus and aedes (stegomyia) aegypti with wuchereria bancrofti.a study was conducted to determine the susceptibility of local strains of culex quinquefasciatus and aedes aegypti to infection with the strain of wuchereria bancrofti that occurs in maceió. state of alagoas, brazil. cx. quinquefasciatus blood fed simultaneously on the same microfilariae carrier ingested more blood and 2-3x more microfilariae than ae. aegypti. survival rates of both species of insects living for 21 days after blood feeding on microfilaraemic patients were not significantly diffe ...19989921316
lethal effect of rickettsia rickettsii on its tick vector (dermacentor andersoni).rickettsia rickettsii, the causative agent of rocky mountain spotted fever, was lethal for the majority of experimentally and transovarially infected rocky mountain wood ticks (dermacentor andersoni). overall, 94.1% of nymphs infected as larvae by feeding on rickettsemic guinea pigs died during the molt into adults and 88. 3% of adult female ticks infected as nymphs died prior to feeding. in contrast, only 2.8% of uninfected larvae failed to develop into adults over two generations. infected fem ...19999925615
plasmodium gallinaceum ookinetes adhere specifically to the midgut epithelium of aedes aegypti by interaction with a carbohydrate ligand.during the course of its development in the mosquito and transmission to a new vertebrate host, the malaria parasite must interact with the mosquito midgut and invade the gut epithelium. to investigate how the parasite recognizes the midgut before invasion, we have developed an in vitro adhesion assay based on combining fluorescently labelled ookinetes with isolated midgut epithelia from blood-fed mosquitoes. using this assay, we found that plasmodium gallinaceum ookinetes readily adhered to mid ...19999929452
comparative linkage maps for the mosquitoes (culex pipiens and aedes aegypti) based on common rflp loci.we report construction of a comparative linkage map for the mosquito (culex pipiens) based on restriction fragment length polymorphisms (rflps) using cdna clones from aedes aegypti as probes to southern blots of cx. pipiens genomic dna. seventy-one cdna clones were screened for hybridization and genetic diversity among three cx. pipiens strains. fifty-two of 71 cdna clones, isolated from and previously mapped in ae. aegypti (73.2%), were hybridized under high-stringency conditions with cx. pipie ...19999987925
the identification of markers segregating with resistance to schistosoma mansoni infection in the snail biomphalaria glabrata.both snail and parasite genes determine the susceptibility of the snail biomphalaria glabrata to infection with the trematode schistosoma mansoni. to identify molecular markers associated with resistance to the parasite in the snail host, we performed genetic crosses between parasite-resistant and -susceptible isogenic snails. because resistance to infection in adult snails is controlled by a single locus, dna samples from individual f2 and f1 backcross progeny, segregating for either the resist ...19999990054
trapping cdnas encoding secreted proteins from the salivary glands of the malaria vector anopheles gambiae.the signal sequence trap method was used to isolate cdnas corresponding to proteins containing secretory leader peptides and whose genes are expressed specifically in the salivary glands of the malaria vector anopheles gambiae. fifteen unique cdna fragments, ranging in size from 150 to 550 bp, were isolated and sequenced in a first round of immunoscreening in cos-7 cells. all but one of the cdnas contained putative signal sequences at their 5' ends, suggesting that they were likely to encode sec ...19999990055
utilization of human blood and sugar as nutrients by female aedes aegypti (diptera: culicidae).we examined the utilization of sugar and human blood as nutrient sources for small and large female aedes aegypti (l.) when they were fed blood 2 or 5 d after emergence. laboratory-reared mosquitoes were fed human blood alone or sugar plus human blood and assayed at 4, 12, 24, and 48 h after the blood meal. starved and well-fed mosquitoes were obtained by holding teneral females (< or = 1 d old) with 0, 5, 10, and 15% sucrose solutions ad libidum from emergence. both small and large mosquitoes i ...199910071487
partitioning of glycogen, lipid, and sugar in ovaries and body remnants of female aedes aegypti (diptera: culicidae) fed human blood.we examined the accumulation of glycogen, lipid, and sugar obtained from a human blood meal for egg development and body energy reserves by small and large female aedes aegypti (l.). small and large mosquitoes were fed a single meal of human blood on day 2 after emergence. mosquitoes were collected at 4, 12, 24, 48, and 72 h after blood feeding and ovaries and body remnants were separated by dissection and then assayed. large mosquitoes had greater reserves than small mosquitoes. mosquitoes depo ...199910071488
differences in energy metabolism and adult desiccation resistance among three aedes (stegomyia) species (diptera: culicidae) from south sulawesi, indonesia.to determine the mechanisms of adult desiccation resistance of aedes (stegomyia) species, we estimated the carbohydrate and lipid contents of newly emerged adult mosquitoes from south sulawesi, indonesia. inter- and intraspecific differences in glycogen and free fatty acid accumulation were found in aedes aegypti (l.), ae. albopictus (skuse), and ae. paullusi (stone & farmer). high glycogen content was determined for both sexes in all ae. aegypti strains and in the ujung pandang strain of ae. al ...199910071500
variation in oral susceptibility to dengue type 2 virus of populations of aedes aegypti from the islands of tahiti and moorea, french polynesia.twenty three samples of aedes aegypti populations from the islands of tahiti and moorea (french polynesia) were tested for their oral susceptibility to dengue type 2 virus. the high infection rates obtained suggest that the artificial feeding protocol used was more efficient than those previously described. statistical analysis of the results allowed us to define two distinct geographic areas on tahiti with respect to the susceptibility of ae. aegypti: the east coast, with homogeneous infection ...199910072154
replication of dengue type 2 virus in culex quinquefasciatus (diptera: culicidae).we were able to infect culex quinquefasciatus by the parenteral route with dengue virus type 2. the percentage of mosquitoes infected was dose dependent and we obtained a rate of 45.6% infected cx. quinquefasciatus when a 10(5.9) mid50 (mosquito infectious dose for 50% of the individuals as measured in aedes aegypti) of dengue virus type 2 per mosquito was used. infection was detected by an immunofluorescent assay performed on mosquito head squashes 14 days after infection. the replication of de ...199910072159
gene targeting in the silkworm by use of a baculovirus.the bombyx mori fibroin light (l)-chain gene was cloned and the green fluorescent protein (gfp) gene inserted into exon 7. the chimeric l-chain-gfp gene was used to replace the polyhedrin gene of autographa californica nucleopolyhedrovirus (acnpv). this recombinant virus was used to target the l-chain-gfp gene to the l-chain region of the silkworm genome. female moths were infected with the recombinant virus and then mated with normal male moths. genomic dna from their progenies was screened for ...199910072379
efficient expression of mosquito-larvicidal proteins in a gram-negative bacterium capable of recolonization in the guts of anopheles dirus larva.the gram-negative bacterium, an11/2 g1, isolated from the guts of anopheles dirus mosquito larvae, was identified as enterobacter amnigenus. the e. amnigenus was able to recolonize in the gut of an. dirus larva but not in those of aedes aegypti and culex quinquefasciatus larvae. it was able to float in water for a longer period than bacillus thuringiensis subsp. israelensis and bacillus sphaericus. these are desirable characteristics for a delivery vehicle of mosquito-larvicidal toxins for the c ...199910077823
mosquito feeding modulates th1 and th2 cytokines in flavivirus susceptible mice: an effect mimicked by injection of sialokinins, but not demonstrated in flavivirus resistant mice.culex pipiens and aedes aegypti mosquitoes were fed on c3h/hej mice and systemic cytokine production was quantified from stimulated lymphocytes harvested four to ten days after feeding. mosquito feeding on c3h/hej mice significantly down regulated ifn gamma production seven to ten days post feeding by cx. pipiens and seven days after ae aegypti feeding. th2 cytokines, il-4 and il-10, were significantly up regulated 4-7 days after cx. pipiens and ae. aegypti feeding. the immunosuppressive effect ...199910081770
bacterial control of mosquito larvae: investigation of stability of bacillus thuringiensis var. israelensis and bacillus sphaericus standard powders.bacillus thuringiensis var. israelensis and bacillus sphaericus products were assayed against their respective reference powders ips82 and sph88. since their production in 1982 and 1988, the potency and larvicidal activity of these standard powders have been regularly checked on their test insects aedes aegypti (for ips82) or culex pipiens (for sph88). over the 16-year evaluation period of ips82 and 10-year evaluation period of sph88, their potencies were considered stable. the global mean of ea ...199810084145
microbiology of the oil fly, helaeomyia petrolei.helaeomyia petrolei larvae isolated from the asphalt seeps of rancho la brea in los angeles, calif., were examined for microbial gut contents. standard counts on luria-bertani, macconkey, and blood agar plates indicated ca. 2 x 10(5) heterotrophic bacteria per larva. the culturable bacteria represented 15 to 20% of the total population as determined by acridine orange staining. the gut itself contained large amounts of the oil, had no observable ceca, and maintained a slightly acidic ph of 6.3 t ...199910103240
behavioural mode of action of deet: inhibition of lactic acid attraction.using the mosquito aedes aegypti in a novel olfactometer that measures movement towards and away from a stimulus, we could not confirm that 'deet' is a repellent of mosquitoes. in the absence of a host, deet was an attractant and in the presence of a host, it was an inhibitor of attraction. this inhibition occurred in the gaseous phase and was therefore not the result of the physical properties of deet. we determined that l-lactic acid, a component of human sweat that is an attractant to mosquit ...199910194755
packaging of aednv-gfp transducing virus by expression of densovirus structural proteins from a sindbis virus expression system.genetic recombination resulting in the production of wild-type infectious virus is an obstacle in the current system for producing densovirus transducing particles. in order to eliminate this problem, a double subgenomic sindbis virus (te/3'2j/vp) was engineered that expresses the structural proteins (vps) of aedes densonucleosis virus (aednv) from the second subgenomic promoter. expression of aednv vps from te/3'2j/vp was confirmed by northern analysis of rna from infected c6/36 (aedes albopict ...199910208920
transduction of aedes aegypti mosquitoes with vectors derived from aedes densovirus.aedes densovirus (aednv)-based constructs that express green fluorescent protein (gfp) from either the p7 or the p61 promoter were made. the construct in which gfp protein was expressed as a fusion protein to the c-terminus of ns1 (ns1-gfp) showed the highest level of gfp expression. this hybrid ns1-gfp protein preserved the biological functions of the parental proteins: it showed gfp fluorescence, it stimulated expression from the virus promoters, and it facilitated rescue and replication of th ...199910208921
vesicular atpase-overexpressing cells determine the distribution of malaria parasite oocysts on the midguts of mosquitoes.in plasmodium-infected mosquitoes, oocysts are preferentially located at the posterior half of the posterior midgut. because mosquitoes rest vertically after feeding, the effect of gravity on the ingested blood has been proposed as the cause of such a biased distribution. in this paper, we examined the oocyst distribution on the midguts of mosquitoes that were continuously rotated to nullify the effect of gravity and found that the typical pattern of oocyst distribution did not change. invasion ...199910212245
antagonism between cry1ac1 and cyt1a1 toxins of bacillus thuringiensismost strains of the insecticidal bacterium bacillus thuringiensis have a combination of different protoxins in their parasporal crystals. some of the combinations clearly interact synergistically, like the toxins present in b. thuringiensis subsp. israelensis. in this paper we describe a novel joint activity of toxins from different strains of b. thuringiensis. in vitro bioassays in which we used pure, trypsin-activated cry1ac1 proteins from b. thuringiensis subsp. kurstaki, cyt1a1 from b. thuri ...199910223999
dengue virus structural differences that correlate with pathogenesis.the understanding of dengue virus pathogenesis has been hampered by the lack of in vitro and in vivo models of disease. the study of viral factors involved in the production of severe dengue, dengue hemorrhagic fever (dhf), versus the more common dengue fever (df), have been limited to indirect clinical and epidemiologic associations. in an effort to identify viral determinants of dhf, we have developed a method for comparing dengue type 2 genomes (reverse transcriptase pcr in six fragments) dir ...199910233934
a cell surface mucin specifically expressed in the midgut of the malaria mosquito anopheles gambiae.an invertebrate intestinal mucin gene, agmuc1, was isolated from the malaria vector mosquito anopheles gambiae. the predicted 122-residue protein consists of a central core of seven repeating ttttvap motifs flanked by hydrophobic n- and c-terminal domains. this structure is similar to that of mucins that coat the protozoan parasite trypanosoma cruzi. northern blot analysis indicated that the gene is expressed exclusively in the midgut of adult mosquitoes. a length polymorphism and in situ hybrid ...199910318932
influence of odour plume structure on upwind flight of mosquitoes towards hostsboth the concentration and the fine-scale plume structure of host odours influence the upwind flight of female mosquitoes aedes aegypti (l.) (diptera: culicidae) in a wind tunnel. the attractive effects of carbon dioxide, human skin odour and l-(+)-lactic acid were tested in homogeneous, turbulent and filamentous odour plumes. with carbon dioxide, the percentage of upwind-flying mosquitoes increased with the increasing fluctuations in concentration that occur in turbulent and filamentous plumes. ...199910333509
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