A comparison of molecular markers to detect Lutzomyia longipalpis naturally infected with Leishmania (Leishmania) infantum

The aim of the present study was to detect natural infection by Leishmania (Leishmania) infantum in Lutzomyia longipalpis captured in Barcarena, state of Pará, Brazil, through the use of three primer sets. With this approach, it is unnecessary to previously dissect the sandfly specimens. DNA of 280 Lu. longipalpis female specimens were extracted from the whole insects. PCR primers for kinetoplast minicircle DNA (kDNA), the mini-exon gene and the small subunit ribosomal RNA (SSU-rRNA) gene of Leishmania were used, generating fragments of 400 bp, 780 bp and 603 bp, respectively. Infection by the parasite was found with the kDNA primer in 8.6% of the cases, with the mini-exon gene primer in 7.1% of the cases and with the SSU-rRNA gene primer in 5.3% of the cases. These data show the importance of polymerase chain reaction as a tool for investigating the molecular epidemiology of visceral leishmaniasis by estimating the risk of disease transmission in endemic areas, with the kDNA primer representing the most reliable marker for the parasite.

Characterization of 23S rRNA domain V mutations in gastric biopsy patients from the eastern Amazon

Resistance of Helicobacter pylori to clarithromycin is characterised by simple point mutations in the 23S ribosomal RNA (rRNA) gene and is responsible for the majority of cases of failure to eradicate this bacterium. In this paper, we characterised the variability of the 23S rRNA gene in biopsies of patients with gastric pathologies in the eastern Amazon (Northern Region of Brazil) using PCR and sequencing. A total of 49 sequences of H. pylori strains were analysed and of those, 75.6% presented nucleotide substitutions: A2142G (3.3%), T2182C (12.9%), G2224A (6.45%), T2215C (61.3%), A2192G (3.3%), G2204C (6.4%) and T2221C (6.4%). Of the mutations identified, four are known mutations related to cases of resistance and 16.1% are not yet described, revealing a high prevalence of mutations in the H. pylori 23S rRNA gene among the strains circulating in the in the eastern Amazon. The high prevalence in individuals with gastric pathologies in the Northern Region of Brazil demonstrates the need for characterising the profile of these strains to provide correct therapy for patients, considering that mutations in this gene are normally associated with resistance to the primary medication used in controlling H. pylori infection.

Filogenia molecular dos xenarthra (Mammalia): análise do grupo cingulata a partir de sequências nucleotídicas do gene mitocondrial rRNA 16S

Os Xenarthra são o grupo de mamíferos que inclui os tatus, os tamanduás e as preguiças. A América do Sul serviu de cenário para a história natural do grupo que, somente no fim do Cenozóico, dispersou-se para a América Central e, com uma perda de variedade, chegou à América do Norte e à algu-mas ilhas do Caribe. Trinta e uma espécies estão descritas dentro da linha-gem dos Xenarthra. Elas estão classificadas em 13 gêneros, quatro famílias (Bradypodidae, Megalonychidae, Myrmecophagidae e Dasypodidae) e duas ordens (Cingulata e Pilosa). A filogenia deste grupo tem sido alvo de diver-sas pesquisas que analisaram tanto dados morfológicos, quanto moleculares. Delsuc et al. (2003) analisaram seqüências de genes mitocondriais e nucleares e confirmaram a monofilia das três subfamílias (Dasypodinae, Euphacti-nae e Tolypeutinae) inclusas na família Dasypodidae. Delsuc et al. (2003) geraram a seguinte árvore: (((Bradypus, Choloepus)100, ((Myrmecophaga, Tamandua)100, Cyclopes)100), ((D. kappleri, D. novemcinctus)100, (Toly-pentes, (Priodontes, Cabassous)54)100, (Zaedyus, (Euphractus, Chaetophrac-tus)60)100)). Gaudin (2005) apresentou um trabalho que reviu e ampliou as análises morfológicas apresentadas até então, concluindo que os tatus atu-ais estão divididos em dois grupos, um mais basal (Dasypodinae) e outro mais derivado (Euphractinae), de acordo com o seguinte arranjo: (Bradypus, Tamandua), (Dasypus, (Priodontes, (Cabassous, (Tolypeutes, (Euphractus, Chaetophractus, (Zaedyus, Chlamyphorus)42)36)72)72)40)85). Neste traba-lho utilizou-se parte do gene mitocondrial rRNA 16S de 12 táxons atu-ais de Xenarthra para analisar a filogenia do grupo através do critério de máxima verossimilhança. Nossos resultados são apresentados analisando-se o gene 16S e analisando o banco de dados do 16S mais o de Delsuc et al. (2003). Nas duas situações, as filogenias apresentadas apóiam os resulta-dos de Delsuc et al. (2003): (Bradypus, (Choloepus, ((Cyclopes, (Myrme-cophaga, Tamandua)100)100, (Dasypus, (((Cabassous, Priodontes)68, Toly-peutes)100,((Chaetophractus, Euphractus)65, Zaedyus)100)100)100)100)100). Uma melhora nos valores de bootstrap nos ramos dentro das sub-famílias da família Dasypodidae é percebida em relação ao trabalho de Delsuc et al. (2003). Acreditamos que Elementos de Transposição do tipo (LINES) são os marcadores moleculares mais adequados para confirmar o arranjo obtido com as seqüências de genes mitocondriais e nucleares.

Prevalence and genotyping of hepatitis C virus in blood donors in the state of Pará, Northern Brazil

Given the scarcity of epidemiological information on hepatitis C virus (HCV) infection in Northern Brazil, we determined the prevalence and genotypic frequency in blood donors in the state of Pará (PA). Blood samples from all of the blood donors at the Fundação HEMOPA (blood bank of PA) from 2004-2006 were screened for the presence of antibodies to anti-HCV and samples seroreactive to anti-HCV were further tested for HCV RNA using real-time PCR. In total, 116 HCV-RNA samples were genotyped, based on maximum likelihood phylogenetic analyses, using BioEdit, Modelgenerator, PHYML and FigTree software. The population consisted of 242,726 volunteers who donated blood from 2004-2006; the most common subgroup was males between the ages of 18-29 years old (37.30%). Within the whole group, 1,112 blood donors (0.46%) had indeterminate or positive serology; among these, 28.78% were males whose ages ranged from 18-29 years. A diagnosis of chronic HCV infection was confirmed for 304 donors (60.20% males; 66.45% were 30-49 years old), resulting in a prevalence of HCV RNA in 0.13% of the samples (304 of 242,726). HCV genotyping revealed a high frequency of genotype 1 (108/116) followed by genotype 3 (8/116). This study found HCV infection to be relatively infrequent in PA; genotype 1 was most commonly isolated. This information can help guide prevention and control policies aimed at efficient diagnosis and control measures.