Immunofluorescence detection of Bartonella bacilliformis flagella in vitro and in vivo in human red blood cells as viewed by laser confocal microscopy.
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Bartonella↗
Biomedical subjects
H Guerra
Publications and source records attributed to H Guerra.
The acrosomic reaction in stallion spermatozoa: inductive effect of the mare preovulatory follicular fluid.
In the female genital tract, spermatozoa must undergo capacitation and acrosome reaction prior to fertilization. A number of factors may induce physiological acrosome reaction assayed in vitro. The aims of this study are to determine the inductive effect of the preovulatory follicular fluid on the sperm acrosomal status in the equine, once some characteristics of the follicular fluid during folliculogenesis had been evaluated. The spermatozoa were obtained from cauda epididymes of adult stallion. Follicular fluid was taken from mare ovarian follicles classified according to their diameter. In these fluids, total protein, progesterone, estradiol and osmolarity were determined. Afterwards, the effect of preovulatory follicular fluid (50%) upon induction of the acrosomic reaction in stallion capacitated spermatozoa was assayed. Results show that during folliculogenesis the ratio progesterone/estrogen is below 1. In large preovulatory follicles, there is a sharp increase of progesterone, reaching a ratio progesterone/estrogen close to 4. Protein concentration and osmolarity increase together with follicular development, being osmolarity very high at the preovulatory stage. Follicular fluid--in vitro--increases the percentage of spermatozoa with acrosome reaction, maintaining high rates of vitality and motility. The characteristics of follicular fluid undergo dynamic changes during the folliculogenesis, such as steroid level, protein concentration and osmolarity. These events may play a role in the reproductive process in vivo, considering that in vitro the follicular fluid is a very effective inductor of the acrosome reaction, with optimum levels of vitality and motility.
Acrosome Reaction↗
Differences in the contents of total sugars, reducing sugars, starch and sucrose in embryogenic and non-embryogenic calli from Medicago arborea L.
The total sugars, reducing sugars, starch and sucrose in embryogenic and non-embryogenic calli from explants (cotyledons, petioles, hypocotyls and leaves) obtained from Medicago arborea L. seedlings were evaluated. Total sugars were the major components in the calli and no significant differences between embryogenic and non-embryogenic calli were observed. In contrast, important differences between the embryogenic and non-embryogenic calli were observed for reducing sugars, the highest levels being observed in embryogenic calli. The highest starch levels were found in non-embryogenic calli developed in MS medium. During the development of somatic embryogenesis very low starch levels in the callus were found. During the first months of culture, no significant differences in the sucrose content were found between calli that produced embryos and those that did not. The most important differences in sucrose were seen between calli transferred to medium F0, which had the greatest embryogenic capacity, and those transferred to medium F6, which inhibited embryogenesis. In the latter case, an increase in sucrose was observed.
Journal Article↗
Surveillance of bacterial pathogens associated with acute diarrhea in Lima, Peru.
OBJECTIVES: A study was conducted in Lima, Peru, from January to April 1995, to determine the bacterial pathogens associated with acute diarrhea in adults, their susceptibility to common antimicrobials, the risk factors involved in cholera transmission, and the best clinical predictors of cholera. METHODS: A random sample of adult patients with acute diarrhea was studied. Epidemiologic and clinical data and risk factors to acquire diarrheal diseases were evaluated. Identification of bacteria and susceptibility to antimicrobials were determined. RESULTS: The study included 336 patients. Vibrio cholerae O1 (52.7%), Shigella spp. (4. 8%), and Salmonella spp (2.7%) were the pathogens most commonly isolated. No resistance to antimicrobials was observed. Patients with cholera had less access to municipal water (P = 0.0018) and were less likely to have homes connected to a sewage system (P = 0. 0003) or to have indoor toilet facilities (P = 0.0001) than those without cholera. Liquid stools (odds ratio [OR] = 16.51; confidence interval [CI] = 13.71-19.02; P = 0.003), severe dehydration (OR = 2. 48; CI = 1.57-3.38; P = 0.0083), generalized cramps (OR = 4.63; CI = 3.10-6.17, P < 0.0001), and washerwoman's hands (OR = 2.45; CI = 1. 55-3.34; P = 0.017) were the best clinical predictors of cholera in this setting. CONCLUSIONS: Cholera is still prevalent in Lima, and people living in environments with low sanitary conditions are especially at risk. Clinical signs of severe dehydration and liquid stools were the best predictors of cholera.
Adolescent↗
Clinical application of a dot blot test for diagnosis of enteric fever due to Salmonella enterica serovar typhi in patients with typhoid fever from Colombia and Peru.
Clinical application of a dot blot test to detect immunoglobulin G (IgG) (88% sensitivity and specificity) and IgM (12.1% sensitivity and 97% specificity) against flagellar antigen from Salmonella enterica serovar Typhi was performed in Peruvian and Colombian patients with typhoid fever. This test can be used as a good predictor of serovar Typhi infection in regions lacking laboratory facilities and in field studies.
Adolescent↗
Development of the Instituto de Medicina Tropical Alexander von Humboldt of the Universidad Peruana Cayetano Heredia. Plus some reflections on tropical medicine research in developing countries in the 21st century....
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Academies and Institutes↗
Survey of three bacterial louse-associated diseases among rural Andean communities in Peru: prevalence of epidemic typhus, trench fever, and relapsing fever.
Typhus and other louse-transmitted bacterial infections in Peruvian sierra communities are known to occur but have not recently been assessed. In this study, 194 of 1,280 inhabitants of four villages in Calca Province in the Urubamba Valley were included. Thirty-nine (20%) of the 194 volunteers had antibodies to Rickettsia prowazekii, whereas 24 (12%) had antibodies to Bartonella quintana and 2 against Borrelia recurrentis. There was a significant correlation between the presence of infesting ectoparasites and antibodies to R. prowazekii, as well as between antibodies to R. prowazekii and ectoparasite infestation and fever in the previous 6 months. The proportion of inhabitants infested with ectoparasites was significantly higher in the highest-altitude village than in the other three villages. Two volunteers' antibody levels suggested a recent typhus infection, but only B. quintana DNA was amplified from lice. Epidemic typhus remains extant in the area, and B. quintana infections were encountered and documented for the first time in South America.
Adult↗
Survey of Bartonella species infecting intradomicillary animals in the Huayllacallán Valley, Ancash, Peru, a region endemic for human bartonellosis.
The natural cycle of Bartonella bacilliformis remains uncertain, and the suspected existence of animal reservoirs for the bacterium has never been convincingly demonstrated. We conducted a survey of Bartonella species infecting intradomicillary animals in a bartonellosis-endemic region of Peru, obtaining blood from 50 animals living in the homes of 11 families whose children had recently had bartonellosis. Bartonella-like bacteria were recovered from four of nine small rodents included in the study, but from none of the 41 domesticated animals. Identification and comparison of these isolates, and two Bartonella-like isolates obtained from Phyllotis mice in a different endemic region of Peru using serologic and genotypic methods indicated that although none were strains of B. bacilliformis, five were probably representatives of three previously unrecognized Bartonella species and one was a likely strain of the pathogenic species B. elizabethae.
Animals↗
Cholera in Lima, Peru, correlates with prior isolation of Vibrio cholerae from the environment.
The authors utilized a recently developed DNA probe technique to obtain quantitative data on occurrence of Vibrio cholerae in samples collected monthly from 12 environmental sites in Lima, Peru, from November 1993 through March 1995. Peak V. cholerae counts ranged from 10(2)/ml to 10(5)/ml, with the highest counts in sewage-contaminated areas and irrigation water. With our methodology, no V. cholerae cases were detected at any site during the winter months of July through October. Counts were detectable in the environment before onset of cholera in the community, with counts at "cleaner" sites upriver correlating significantly with occurrence of community disease 2 and 3 months later. In sites with heavy sewage contamination, V. cholerae could still be detected before the onset of cases in the community; however, in contrast to upriver sites, counts at these latter sites correlated most closely with the number of concurrently occurring cholera cases. These data support a model of cholera seasonality in which initial increases in number of V. cholerae in the environment (possibly triggered by temperature) are followed by onset of illness in the community, with these human cases further amplifying the organism as the epidemic cycle proceeds.
Cholera↗
Fasciola hepatica cysteine proteinases: immunodominant antigens in human fascioliasis.
Fasciola hepatica adult worm cysteine proteinases were active-site, affinity radio-labeled with benzyloxicarbonyl-L-tyrosine-L-alanine diazomethylketone (Z-Tyr125I-Ala-CHN2). Sera from patients with fascioliasis and from rabbits experimentally infected with F. hepatica immunoprecipitated the radiolabeled parasite cysteine proteinases in immunoelectrophoresis assays. Two purified antigens were identified as part of the complex mosaic of antigens immunoprecipitated by the sera of infected patients. These antigens (Fas1 and Fas2) have been shown to be an important part of the Fharc2 precipitin band used for serologic diagnosis in humans and cattle. They showed cysteine proteinase activity with different proteolytic specificities and partial identity in double immunodiffusion assays. The results obtained in this work show that the Fas1 and Fas2 antigens are sensitive and specific antigens for diagnosis of this serious helminthic disease in humans and other susceptible hosts.
Animals↗
Cloning and characterization of dnaE, encoding the catalytic subunit of replicative DNA polymerase III, from Vibrio cholerae strain C6706.
We report that Vibrio cholerae (Vc) contains a gene homologous to Escherichia coli dnaE, the structural gene for the alpha (catalytic) subunit of replicative DNA polymerase III (PolIII). Despite 24% amino acid (aa) differences in the encoded proteins, the Vc gene strongly complements an E. coli dnaE temperature sensitive (ts) mutant, indicating that all functional features essential for replication are conserved.
Amino Acid Sequence↗
Karyotype plasticity in neotropical Leishmania: an index for measuring genomic distance among L. (V.) peruviana and L. (V.) braziliensis populations.
A method for phenetic analysis of karyotype data has been developed for Leishmania populations. Measurement of size difference between chromosomes recognized by a given DNA probe in different isolates led to the formulation of a Chromosome Size Difference Index (CSDI). The method was applied to phenetic analysis of 4 sets of chromosomes--each set being recognized by a different probe--in 37 L. (Viannia) peruviana isolates sampled along a North-South transect through the Peruvian Andes and, in 11 L. (V.) braziliensis isolates from the Amazonian forest (Peru, Bolivia and Brazil). Karyotype variability was better accounted for by CSDI than by a method based on disjunctive encoding of karyotype data. CSDI evidenced the nature of relationships between L. braziliensis and L. peruviana and it provided a coherent picture of geographical and genomic differentiation among parasite populations. The latter did cluster according to their geographical origin. L. braziliensis was found karyotypically more homogeneous than L. peruviana. Within L. peruviana, Northern populations were closer to L. braziliensis than to Southern L. peruviana populations. The validity of karyotypic populations, or karyodemes, was sustained.
Animals↗
Identification of bloodmeal sources of Lutzomyia spp. in Peru.
Bloodmeal sources of Lutzomyia spp. were determined, using the bloodmeal analysis precipitin test, in Chaute, Lima, Peru, an area endemic for cutaneous leishmaniasis (uta). From April 1990 to May 1991, sandflies were sampled in and around the village houses, with CDC light traps and a Shannon trap with protected human bait, respectively. Overall, 1424 sandflies were collected engorged. In indoor collections, human blood (N = 275) was the most frequent bloodmeal found, followed by cow (171) and cat (152). The most frequent bloodmeals of the flies caught in the Shannon trap collections were from cow (31), man (23) and cat (23). Of the two predominant sandfly species in the area, Lutzomyia peruensis was more anthropophilic than Lu. verrucarum (chi 2 = 14.13, P < 0.001). The sandflies from Chaute appear to be opportunistic feeders; 16 different hosts were identified. There was evidence of bloodmeals from more than one host in each of 151 sandflies, including bloodmeals containing blood from an animal only present within the houses mixed with blood from animals only present in the corrals near the house. Some sandflies must therefore have flown from the corrals to the houses (or vice versa) to take the last bloodmeals before their capture.
Animals↗
Karyotype polymorphism and conserved characters in the Leishmania (Viannia) braziliensis complex explored with chromosome-derived probes.
Molecular karyotype of 45 reference populations of Neotropical leishmanias was analyzed with ethidium bromide staining and with 6 chromosome-derived probes selected from a genomic library of Leishmania (Viannia) braziliensis. Size-conserved patterns were identified and found to be specific to subgenus Viannia and to its constitutive species. An important issue for epidemiology and clinical investigations was the discrimination between L. (V.) peruviana and L. (V.) braziliensis, 2 species found very similar by other genetic techniques, but responsible for totally different clinical patterns. The suggested existence of genetically distinct demes, or karyodemes, within the group-species might also show to be of importance, as these populations might differ in virulence, host-specificity and clinical manifestations.
Animals↗
Genetic heterogeneity in Peruvian Leishmania isolates.
Leishmania were isolated from Peruvian patients with uta or espundia; genomic DNA was examined for restriction fragment length differences by Southern blot analysis using DNA probes for beta-tubulin and for the major surface antigen gp63. Using 5 different restriction endonucleases, Peruvian isolates show homogeneity when examined at the beta-tubulin locus. In contrast, the organisms demonstrated heterogeneity both within and between disease groups when examined for restriction site differences within the gp63 locus. The differences observed did not correlate with the 2 disease groups. Comparison of these Peruvian isolates to New World reference strains of the Leishmania braziliensis complex reveals no consistent pattern of identity with either L. b. guyanensis, L. b. panamensis, or L. b. braziliensis.
Animals↗
Diagnosis of typhoid fever using a string capsule device.
Cultures were made from blood, bone marrow, stool and duodenal contents (obtained with string capsules) from 36 patients with bacteriologically proven typhoid fever on admission to hospital. Duodenal content cultures proved to be as sensitive in diagnosis (86%) as bone marrow (75%) and more effective than blood (42%) and stool (26%) cultures in recovery of Salmonella typhi. The sensitivity of duodenal content cultures was not modified by the duration of illness at admission or by previous antibacterial therapy. Even on the seventh day of effective treatment with chloramphenicol, the culture of duodenal contents remained positive in 8 of 17 patients, whereas salmonellae were isolated from stool cultures in only 2 of the same patients. The results obtained with the string capsule, together with the simplicity, economy and acceptability of the procedure, the fact that it can be performed with minimal facilities and the advantages of bacteriological recovery for antibiotic sensitivity testing, suggest that its adoption would be very helpful in efforts to control this disease.
Bacteriological Techniques↗
Changes in nitrogen fractions and proteolytic activities in the cotyledons of germinating lentils.
Changes in ninhydrin positive material, free amino acids and protein content during germination of seeds of Lens culinaris Med. have been studied. Ninhydrin positive material and free amino acids reached their highest concentration at the fifth day of germination. Total protein which represents 21% of the total dry weight of the lentil cotyledons, suffers a degradation of only 24% in seven days of germination; in the same period of time, reserve proteins underwent a degradation of 69%, legumin being the more abundant at the start, and the more rapidly depleted. Five different classes of proteolytic activities have been reported in lentil cotyledons: caseinolytic, active against the reserve proteins of the lentil cotyledons themselves, aminopeptidase, peptidehydrolase, carboxypeptidase and dipeptidase. The removal of the axis did not seem to exert any significant influence on the enzymatic activity.
Amino Acids↗
Purification and characterization of two proteolytic enzymes in the cotyledons of germinating lentils.
Two proteases, one peptidehydrolase and one aminopeptidase, have been purified to homogeneity from cotyledons of germinating seeds of Lens culinaris Med. Peptidehydrolase has an apparent molecular weight of 89,000 and an isoelectric point of 4.7. Peptidehydrolase activity was not affected by metal chelators but it was affected by N-bromosuccinimide, phenylmethylsulfonyl fluoride and N-ethylmaleimide, suggesting the presence of tryptophan and serine residues together with free--SH groups in its active site. Peptidehydrolase activity was maximally active from pH 6.0 to 9.0 being practically zero below pH 5.0. It was stable at temperatures up to 40 degrees C, and complete inactivation was obtained at or over 70 degrees C. Aminopeptidase has an apparent molecular weight of 83,000 and an isoelectric point of 4.5. Its activity was affected by N-bromosuccinimide, suggesting the presence of tryptophan residues in its active site. The aminopeptidase presents its maximal activity at pH 5.5. It was stable at temperatures up to 40 degrees C, and complete inactivation was detected at over 70 degrees C.
Aminopeptidases↗