ABSTRACT
In the current study, we evaluated the mechanism of action of miltefosine, which is the first effective and safe oral treatment for visceral leishmaniasis, in Leishmania amazonensis promastigotes. Miltefosine induced a process of programmed cell death, which was determined by the externalization of phosphatidylserine, the incorporation of propidium iodide, cell-cycle arrest at the sub-G0/G1 phase and DNA fragmentation into oligonucleosome-sized fragments. Despite the intrinsic variation that is detected in Leishmania spp, our results indicate that miltefosine causes apoptosis-like death in L. amazonensis promastigote cells using a similar process that is observed in Leishmania donovani.
Subject(s)
Antiprotozoal Agents , Apoptosis , DNA Fragmentation , DNA, Protozoan , Leishmania mexicana , Phosphorylcholine/analogs & derivatives , DNA, Protozoan , Flow Cytometry , PhosphorylcholineABSTRACT
This study analyzed the involvement of tetA and tetE genes in the tetracycline resistance of 16 strains of genus Aeromonas, isolated from clinical and food sources. Polymerase chain reactions revealed that 37.5 percent of the samples were positive for tetA, and also 37.5 percent were tetE positive. One isolate was positive for both genes. Only the isolate A. caviae 5.2 had its resistance associated to the presence of a plasmid, pSS2. The molecular characterization of pSS2 involved the construction of its restriction map and the determination of its size. The digestion of pSS2 with HindIII originated two fragments (A and B) that were cloned separately into the pUC18 vector. The tetA gene was shown to be located on the HindIII-A fragment by PCR. After transforming a tetracycline-sensitive strain with pSS2, the transformants expressed the resistance phenotype and harbored a plasmid whose size was identical to that of pSS2. The results confirmed the association between pSS2 and the tetracycline resistance phenotype, and suggest a feasible dissemination of tetA and tetE among strains of Aeromonas. This study suggests the spreading tetA and tetE genes in Aeromonas in Brazil and describes a resistance plasmid that probably contributes to the dissemination of the resistance.
Subject(s)
Aeromonas/drug effects , Anti-Bacterial Agents/pharmacology , Antiporters/genetics , Bacterial Proteins/genetics , Lactuca/microbiology , Tetracycline Resistance/genetics , Tetracycline/pharmacology , Aeromonas/genetics , Aeromonas/isolation & purification , Chromosomes, Bacterial/genetics , Microbial Sensitivity Tests , Phenotype , Polymerase Chain ReactionABSTRACT
A multiplex polymerase chain reaction (PCR) assay was performed on 167 thermophilic campylobacters isolated from non-human primates. Samples were first identified by phenotypic methods resulting in 64 Campylobacter jejuni and 103 C. coli strains. Four strains identified biochemically as C. coli, were then determined to be C. jejuni by PCR. Comparison of methodologies showed that the main discrepancies were attributed to the hippurate hydrolysis test and sensitivity to cephalothin and nalidixic acid. Analysis of data showed that the application of phenotypic methods should be supplemented by a molecular method to offer a more reliable Campylobacter identification.
Subject(s)
Animals , Bacterial Typing Techniques/methods , Campylobacter/classification , DNA, Bacterial/analysis , Polymerase Chain Reaction/methods , Campylobacter/genetics , Genotype , Macaca fascicularis , Macaca mulatta , Phenotype , SaimiriABSTRACT
Antissoros específicos, estáveis, com título de até 1/60, para diagnóstico das toxinfeçöes alimentares por Clostridium perfringens foram obtidos com emprego da enterotoxina parcialmente purificada