Microbial contamination of water sources remains a serious problem in the Kathmandu Valley, Nepal. This study was conducted to comprehensively investigate the occurrence of pathogenic bacteria in water samples collected from the valley, most of which were used for drinking and other domestic purposes. The water samples consisted of 10 samples of commercial jar water, 10 of groundwater from shallow dug wells, 3 of groundwater from deep tube wells, 1 of stone spout water, 2 of spring water, and 2 of river water. DNA microarray analysis targeting 941 different pathogenic bacterial species/groups showed the prevalence of Acinetobacter, Arthrobacter, Brevibacterium, Pseudomonas, and Legionella and the presence of biosafety level 3 pathogens in some samples, which were partially confirmed by genus-specific PCR quantification for Legionella and Brucella. Additionally, the occurrence of most pathogens detected via DNA microarray analysis was not correlated with that of fecal indicator bacteria (total coliforms and Escherichia coli). These results will aid in understanding the overall picture of pathogenic bacterial contamination and in screening important pathogens that should be investigated in detail.
Retinoic acid RA receptors RARs are nuclear receptors whose specifi c natural ligands are all-trans RA atRA and 9-cis RA. RARs control aspects of vision, cell differentiation, immune response, and embryonic development in vertebrates. However excess RAR signaling can cause various teratogenic effects on developing vertebrates. In our previous studies, we have revealed that municipal wastewater generally contains RAR agonists, and identifi ed that the major causative compounds are RAs [atRA and 13-cis RA 13cRA ] and 4-oxo-RAs 4-oxo-atRA and 4-oxo13cRA , which are oxidative metabolites of RAs. In this study, to elucidate the fates of RAs and 4-oxo-RAs during wastewater treatment, we investigated the variations in their concentrations and the overall RAR agonistic activity in municipal wastewater treatment plants in Osaka, Japan. Results of this study suggested that RAs and 4-oxo-RAs in wastewater can be readily removed by activated sludge treatment, regardless of season and treatment type, and that unidentifi ed RAR agonists are produced during the treatment and persist in the fi nal effl uent under certain conditions. However, the current RAR agonist level in the fi nal effl uent is unlikely to cause deleterious biological effects.Retinoic acid RA receptor agonists; Activated sludge treatment; Municipal wastewater treatment plant; RAs; 4-Oxo-RAs
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