RESUMO
INTRODUCTION: The Opp system is an ATP-binding cassette-type transporter formed by membrane-associated proteins required for the uptake of oligopeptides in bacteria. In gram-positive bacteria, the Opp system, and particularly the oligopeptide-binding protein (OppA), has been shown to be involved in different aspects of cell physiology, including intercellular communication and binding to host proteins. METHODS: In the present study we began to investigate the Opp system of Streptococcus mutans, the main etiological agent of dental caries. RESULTS: Five opp genes (oppABCDF) organized in a single operon were identified in the genome of the S. mutans UA159 strain. Amino acid sequence analyses showed that the S. mutans OppA is closely related to an ortholog found in Streptococcus agalactiae. Incubation of S. mutans UA159 cells with an anti-OppA-specific serum did not inhibit biofilm formation on polystyrene plates. Moreover, S. mutans UA159 derivatives carrying deletions on the oppA or oppB genes did not show significant growth impairment, increased sensitivity to aminopterin, or defective capacity to form biofilms on polystyrene wells in the presence or not of saliva. Remarkably, only two out of three laboratory strains and one out of seven clinical strains recovered from tooth decay processes harbored a copy of the oppA gene and expressed the OppA protein. CONCLUSION: Collectively, these results indicate that, in contrast to other Streptococcus species, the S. mutans Opp system, and particularly the OppA protein, does not represent an important trait required for growth and colonization.
Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Proteínas de Bactérias/genética , Genes Bacterianos , Oligopeptídeos/metabolismo , Streptococcus mutans/genética , Transportadores de Cassetes de Ligação de ATP/fisiologia , Sequência de Aminoácidos , Aderência Bacteriana/genética , Proteínas de Bactérias/fisiologia , Biofilmes , Proteínas de Transporte/genética , Proteínas de Transporte/fisiologia , Cárie Dentária/microbiologia , Humanos , Lipoproteínas/genética , Lipoproteínas/fisiologia , Família Multigênica , Óperon , Proteínas RecombinantesRESUMO
Here, we describe the situation of canine visceral leishmaniasis in two villages of São José de Ribamar in Maranhão State/Brazil, where human cases have been registered. Blood samples of 36 household crossbred dogs from Sergio Tamer village and 43 dogs from Quinta village were collected and the serum used for serological diagnosis. An Indirect Fluorescent Antibody Test (IFAT) and enzyme-linked immunosorbent assay (ELISA) were used to detect antibodies against Leishmania. The clinical examination showed that 25% of the canine population of Quinta presented a poor body condition and in 39%, ectoparasites (ticks and fleas) were detected. In both tests, serology revealed that 21% (9 out of 43) of the dogs presented antibodies against Leishmania (55% were asymptomatic and 45% were symptomatic). In the Vila Sérgio Tamer, 25% (9 out of 36) of the dogs were seropositive for Leishmania (66.67% were asymptomatic and 33.33% were symptomatic), 33% presented poor body condition, and 22% have ectoparasites. The clinical signs more frequent were skin lesions. The statistical analysis showed that there was no statistical difference (p>0.05) between the seropositivity of the dogs from the two villages. The same was observed when the clinical signs were compared (p>0.05). Both villages have favorable conditions to maintain the cycle of leishmaniasis.
