ABSTRACT
BACKGROUND: The deletions of azoospermic factor regions (AZF) are considered risk factor of spermatogenic failure. AZF duplications or complex copy number variants (CNVs) were rarely studied because STS-PCR could not always detect these changes. The application of multiplex ligation-dependent probe amplification (MLPA) as a valuable test for detection of the deletion and or duplication was introduced to investigate the AZF sub-region CNVs. The MLPA technique is still not applied on a large scale, and the publications in this area of research are limited. The aim of this work was to evaluate the efficacy of MLPA assay to detect AZF-linked CNVs in idiopathic spermatogenic failure patients and to evaluate its importance as a prognostic marker in the reproduction outcome. RESULTS: Forty infertile men (37 with azoospermia and 3 with severe oligozoospermia) and 20 normal fertile men were subjected to thorough clinical, pathological, and laboratory assessment, chromosomal study, MLPA, STS-PCR assays, histopathology study, and testicular sperm retrieval (TESE). Out of the 40 patients, 7 patients have shown CNV in the AZFc region, 6 patients have partial deletion, and one patient has partial duplication. Only one of the normal control has AZFc duplication. STS-PCR was able to detect the deletion in only 4 out of the 7 positive patients and none of the control. CONCLUSION: We concluded that MLPA should be applied on a larger scale for the detection of Y chromosome microdeletion as a rapid, efficient, and cheap test.
ABSTRACT
Previous work has shown that microbial communities in As-mobilizing sediments from West Bengal were dominated by Geobacter species. Thus, the potential of Geobacter sulfurreducens to mobilize arsenic via direct enzymatic reduction and indirect mechanisms linked to Fe(III) reduction was analyzed. G. sulfurreducens was unable to conserve energy for growth via the dissimilatory reduction of As(V), although it was able to grow in medium containing fumarate as the terminal electron acceptor in the presence of 500 muM As(V). There was also no evidence of As(III) in culture supernatants, suggesting that resistance to 500 muM As(V) was not mediated by a classical arsenic resistance operon, which would rely on the intracellular reduction of As(V) and the efflux of As(III). When the cells were grown using soluble Fe(III) as an electron acceptor in the presence of As(V), the Fe(II)-bearing mineral vivianite was formed. This was accompanied by the removal of As, predominantly as As(V), from solution. Biogenic siderite (ferrous carbonate) was also able to remove As from solution. When the organism was grown using insoluble ferrihydrite as an electron acceptor, Fe(III) reduction resulted in the formation of magnetite, again accompanied by the nearly quantitative sorption of As(V). These results demonstrate that G. sulfurreducens, a model Fe(III)-reducing bacterium, did not reduce As(V) enzymatically, despite the apparent genetic potential to mediate this transformation. However, the reduction of Fe(III) led to the formation of Fe(II)-bearing phases that are able to capture arsenic species and could act as sinks for arsenic in sediments.
