RESUMO
An important virulence factor for the fungal pathogen Candida glabrata is the ability to adhere to the host cells, which is mediated by the expression of adhesins. Epa1 is responsible for â¼95% of the in vitro adherence to epithelial cells and is the founding member of the Epa family of adhesins. The majority of EPA genes are localized close to different telomeres, which causes transcriptional repression due to subtelomeric silencing. In C. glabrata there are three Sir proteins (Sir2, Sir3 and Sir4) that are essential for subtelomeric silencing. Among a collection of 79 clinical isolates, some display a hyperadherent phenotype to epithelial cells compared to our standard laboratory strain, BG14. These isolates also express several subtelomeric EPA genes simultaneously. We cloned the SIR2, SIR3 and SIR4 genes from the hyperadherent isolates and from the BG14 and the sequenced strain CBS138 in a replicative vector to complement null mutants in each of these genes in the BG14 background. All the SIR2 and SIR4 alleles tested from selected hyper-adherent isolates were functional and efficient to silence a URA3 reporter gene inserted in a subtelomeric region. The SIR3 alleles from these isolates were also functional, except the allele from isolate MC2 (sir3-MC2), which was not functional to silence the reporter and did not complement the hyperadherent phenotype of the BG14 sir3Δ. Consistently, sir3-MC2 allele is recessive to the SIR3 allele from BG14. Sir3 and Sir4 alleles from the hyperadherent isolates contain several polymorphisms and two of them are present in all the hyperadherent isolates analyzed. Instead, the Sir3 and Sir4 alleles from the BG14 and another non-adherent isolate do not display these polymorphisms and are identical to each other. The particular combination of polymorphisms in sir3-MC2 and in SIR4-MC2 could explain in part the hyperadherent phenotype displayed by this isolate.
Assuntos
Candida glabrata/genética , Candidíase/genética , Proteínas Fúngicas/genética , Lectinas/genética , Candida glabrata/patogenicidade , Candidíase/microbiologia , Proteínas de Ligação a DNA/genética , Regulação Fúngica da Expressão Gênica , Inativação Gênica , Complexo de Inativação Induzido por RNA/genética , Saccharomyces cerevisiae/genética , Proteínas Reguladoras de Informação Silenciosa de Saccharomyces cerevisiae/classificação , Proteínas Reguladoras de Informação Silenciosa de Saccharomyces cerevisiae/genética , Telômero/genéticaRESUMO
OBJECTIVES: Gut microbiota provides beneficial effects under physiological conditions, but is able to contribute to inflammatory diseases in susceptible individuals. Thus, we designed this study to test whether additional intake of symbiotic gel affects specific modifications of gut microbiota in patients with end-stage renal disease (ESRD). METHODS: Eighteen patients with ESRD diagnosis with renal replacement therapy (hemodialysis) were included in this study. They were randomly assigned to 2 treatment groups: (1) test group (nutritional counseling + symbiotic) and (2) control group (nutritional counseling + placebo). Clinical history and the evaluation of Gastrointestinal Symptom Rating Scale were performed. Gut microbiota composition was analyzed by real-time polymerase chain reaction from fecal samples. All subjects were followed for 2 months. RESULTS: Bifidobacterial counts were higher in the second samples (mean: 5.5 ± 1.72 log10 cells/g) than in first samples (4.2 ± 0.88 log 10 cells/g) in the patients of the test group (P = .0344). Also, lactobacilli counts had a little decrease in the test group (2.3 ± 0.75 to 2.0 ± 0.88 log 10 cells/g) and the control group (2.2 ± 0.90 to 1.8 ± 1.33 log 10 cells/g), between the first and the second samples. Gastrointestinal symptoms scores (scale 8-40) were reduced in the test group (start 12 [10-14] and end 9 [8-10]) compared with control group (start 11 [8-21] and end 11 [9-15]). CONCLUSIONS: Short-term symbiotic treatment in patients with ESRD can lead to the increase of Bifidobacterium counts, maintaining the intestinal microbial balance.