ABSTRACT
Quorum sensing (QS) é um tipo de comunicação intercelular descrito em microorganismos. Ela é intermediada por moléculas sinalizadoras (QSMs) liberadas constitutivamente pelos espécimes e por meio delas os microorganismos percebem a densidade populacional. [...] Em fungos, trans,trans-farnesol (t,t-FOH) atua como QSM. Esse isoprenóide regula a virulência de Candida albicans modulando os processos de transição morfológica. O t, t- FOH é produzido por uma rota alternativa a partir do farnesilpirofosfato (FPP), um intermediário da via biossíntética de esteróis. Em protozoários, QS já foi descrita no tripanossomatídeo Trypanossoma brucei. Adicionalmente, o processo de metaciclogênese que ocorre em Leishmania possui características de regulação QS, devido sua relação com a densidade populacional. Interessantemente, fungos e tripanossomatídeos possuem maquinaria própria de síntese de esteróis. Essa similaridade e a descrição do t,t-FOH como QSM em fungos sugere que ele pode desempenhar atividade similar em tripanossomatídeos. Em nossa hipótese, t,t-FOH é uma QSM que causa uma redução da capacidade proliferativa de Leishmania amazonensis quando a cultura atinge um quorum. Porém, o parasito mantem-se viável, de modo que a cultura fica estacionária. Inicialmente constatamos que L. amazonensis libera t,t-FOH ou seus derivados no sobrenadante. [...] Essas observações estão de acordo com o perfil de uma possível QSM. Em seguida determinamos as condições de cultivo em que o t,t-FOH possivelmente atua como QSM nas culturas...
Quorum sensing (QS) is a type of intercellular communication described in microorganisms.It is mediated by signaling molecules (QSMs) constitutively released by specimens andthrough them, the microorganisms sense the population density. [...] Infungi, trans,trans-farnesol (t,t-FOH) acts as QSM. This isoprenoid regulates virulence ofCandida albicans interfering the morphological transitions. t,t-FOH is produced by analternative route from farnesylpyrophosphate (FPP), an intermediate of the sterolbiosynthetic pathway. In protozoa, QS has been described in the trypanosomatidTrypanosoma brucei. Additionally, the metacyclogenesis of Leishmania has caracteristics ofQS regulation, due to its relationship with population density. Interestingly, fungi andtrypanosomatids have their own machinery sterol synthesis. This similarity and thedescription of the t, t-FOH as QSM in fungi suggests that it may play similar activity intrypanosomatids. In our hypothesis, t,t-FOH is a QSM which causes a reduction in theproliferative capacity of Leishmania amazonensis when the culture reaches a quorum.However, the parasite keeps viable, so the culture enters in the stationary phase. Initially, wefound that L. amazonensis releases t,t-FOH or its derivatives in the supernatant. Theconcentration of these metabolites enhances with the increase in population density. Theseobservations are consistent with the profile of a possible QSM. Then, we determined thegrowing conditions in which t,t-FOH possibly acts as QSM. [...] We observed that the concentrations that inhibited the proliferation were also apparently toxic. Consideringthat the t,t-FOH is lipophilic, we decided to remove the lipophilic compounds of thesupernatant...
Subject(s)
Mice , Candida albicans , Leishmania , Quorum Sensing , Trypanosoma brucei bruceiABSTRACT
This study focuses on the geographic distribution of the snail of the genus Biomphalaria and evaluates its infectivity by Schistosoma mansoni in 5264 specimens collected in the municipality of Juiz de Fora, Minas Gerais, Brazil. Of the 31 locations studied, 6 were reservoirs, 11 rudimentary holding ponds, 7 irrigation ditches, 5 lakes, 1 ornamental pond, and 1 waterfall. Intermediate hosts were found only in the rudimentary ponds and ditches, which were 100 percent positive. Using morphological and molecular analysis techniques, B. tenagophila, B. peregrina, and B. straminea were identified. This is the first report of B. stramínea in the municipality, and evaluation of its infective potential revealed susceptibility of 25.4 percent. Although we did not find specimens of Biomphalaria infected by S. mansoni, the data obtained indicate the presence of intermediate hosts, especially in the irrigation ditches in Juiz de Fora, and their proximity to contaminated areas.