BackgroundThe kinetoplast DNA (kDNA) of trypanosomatids consists of an unusual arrangement of circular molecules catenated into a single network. The diameter of the isolated kDNA network is similar to that of the entire cell. However, within the kinetoplast matrix, the kDNA is highly condensed. Studies in Crithidia fasciculata showed that kinetoplast-associated proteins (KAPs) are capable of condensing the kDNA network. However, little is known about the KAPs of Trypanosoma cruzi, a parasitic protozoon that shows distinct patterns of kDNA condensation during their complex morphogenetic development. In epimastigotes and amastigotes (replicating forms) the kDNA fibers are tightly packed into a disk-shaped kinetoplast, whereas trypomastigotes (non-replicating) present a more relaxed kDNA organization contained within a rounded structure. It is still unclear how the compact kinetoplast disk of epimastigotes is converted into a globular structure in the infective trypomastigotes.ResultsIn this work, we have analyzed KAP coding genes in trypanosomatid genomes and cloned and expressed two kinetoplast-associated proteins in T. cruzi: TcKAP4 and TcKAP6. Such small basic proteins are expressed in all developmental stages of the parasite, although present a differential distribution within the kinetoplasts of epimastigote, amastigote and trypomastigote forms.ConclusionSeveral features of TcKAPs, such as their small size, basic nature and similarity with KAPs of C. fasciculata, are consistent with a role in DNA charge neutralization and condensation. Additionally, the differential distribution of KAPs in the kinetoplasts of distinct developmental stages of the parasite, indicate that the kDNA rearrangement that takes place during the T. cruzi differentiation process is accompanied by TcKAPs redistribution.
Boophilus microplus larvae from two different sources were used for the detection of Anaplasma marginale DNA: larvae A, which were collected from a pasture of an endemic farm, and larvae B, which originated from engorged female ticks fed on calves with no clinical signs of disease and with low rickettsemia (approximately 0.01 to 1.0%). Larvae A were collected monthly, from January to May in 2001. Two hundred engorged female ticks fed on calves that provided larvae B were divided into groups of 10 and kept in a controlled environment at either 18 degrees C or 28 degrees C. Fifty larvae were used from each sample for DNA extraction, and 5 muL of DNA were submitted to amplification of the sequence of msp5 gene of A. marginale by polymerase chain reaction (PCR). Seven out of 50 samples of larvae A (14%) were positive for the presence of DNA of A. marginale showing amplified product of 457 bp. Ten out of 91 samples of larvae B (11%) kept at 18 degrees C were positive, and all larvae B at 28 degrees C were negative. Thus, this study confirmed the presence of A. marginale DNA in B. microplus larvae by PCR. The EcoRI restriction enzyme analysis confirmed the specificity of the amplicon, which resulted in two fragments: 265 bp and 192 bp. The sequencing analysis of the amplicon from larvae demonstrated 98% homology with the msp5 sequence from Florida A. marginale strain.
Calodium hepaticum (syn. Capillaria hepatica) is a
nematode of the Capillariidae family that infects rodents and other mammals. In
Brazil, human spurious infections of C. hepaticum have been detected
in indigenous or rural communities from the Amazon Basin, but not in the southern
states of the country. Here, we report the highest occurrence (13.5% of 37 residents)
of C. hepaticum human spurious infection detected in Brazil and the
first record in a southern region, Guaraqueçaba. The finding is explained by the area
being located in the Atlantic Forest of the state of Paraná, surrounded by preserved
forests and because the inhabitants consume the meat of wild mammals.
The present study aims to analyze the prevalence and risk factors of active pediculosis and to compare the efficacy and sensitivity of the vacuum method with the comb method and the visual inspection with a magnifying glass in order to determine the best methodology to detect active pediculosis among schoolchildren from Paraná state. Each child was examined by the three methods in sequence and a playful activity was introduced to increase the children likelihood to participate in the study. Additionally, hair characteristics and other risk factors as sex, age, and area of living were take into consideration to measure epidemiological aspects. From a total of 358 schoolchildren from southern Brazil, overall pediculosis prevalence was 45.5%, while active pediculosis prevalence was 13.1%. Regarding active pediculosis, there was no statistical difference among sex. However, nine-year-old girls were most likely to have active pediculosis. The vacuum method was 5.96 and 11.29 times more efficacious than the magnifying glass method and the comb method, respectively, and also had higher sensitivity (74.5%) in detecting active pediculosis. When analyzing hair characteristics, children with long and wavy/curly hair were more often diagnosed by the vacuum method than children with short and wavy/curly hair. The vacuum method was the most effective method and proved to be an optimal option to detect active pediculosis among schoolchildren, mostly in children with wavy/curly hair.
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