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Objective To find out the hygienic status of rural drinking water in Jianhe County of Guizhou Province.Methods Forty-eight source water and tap water samples from small centralized water supply stations in 12 townships of Jianhe County in dry season and wet period were tested from 2009-2011.The water samples were examined in accordance with the relevant provision of Standard Examination Methods for Drinking Water (B/T5750-2006).The contents included:①sensory indicators:standard color,turbidity,smell and taste and visible objects; ②general chemical indicators:pH,iron,manganese,chloride,sulfate,total dissolved solids,total hardness,oxygen consumption and ammonia; ③toxicological indicators:fluoride,arsenic and nitrate; ④microbial indicators:total number of colonies,with a total population of Escherichia coli and heat-resistant Escherichia coli Outcome evaluation was carried out in accordance with the Drinking Water Health Standards (B/T 5.749-2006).Results A total of 192 rural water samples were collected in 2009-2011,and 18 samples were qualified,accounting for 9.38％.The differences of water passing rate between groups of years were statistically significant (x2 =14.74,P＜ 0.01).Rural drinking water quality in dry season (18.75％,18/96) was better than that in wet season (0.00％,0/96; x2 =19.76,P ＜ 0.01).Passing rate of source water quality (16.67％,16/96) was higher than that of tap water(2.08％,2/96; x2 =11.95,P ＜ 0.01).Sensory indicators and toxicological indicators of 192 water samples were qualified.General chemical indicators:in addition to four water samples with pH exceeded the standard(two copies in 2009 and two copies in 2010),other test indicators were qualified.Microbiological indicators:passing rates of the total number of colonies,Escherichia coli group and heat-resistant Escherichia coli group were 77.08％ (148/192),9.90％ (19/192) and 20.31％ (39/192),respectively.Passing rate of microbes was 18.75％ (18/96) in dry season and 0.00％ (0/96) in wet period,and microbes passing rate was significantly higher in dry season than that of the wet period(x2 =19.76,P ＜ 0.01).Passing rate of microbes was 16.67％(16/96) in source water and 2.08％(2/96) in tap water,and passing rate of the source water was significantly higher than that of the tap water(x2 =11.95,P ＜ 0.01).Conclusions The hygienic status of rural drinking water in rural areas of Jianhe County of Guizhou Province is poor.Microbial pollution is the main reason.
ABSTRACT
To confirm the inactivating effect of chito-oligosaccharides on Tobacco mosaic virus (TMV) par ticles in vitro, the difference of TMV pathogenicity was evaluated according to the decrease of local lesion numbers after inoculating with TMV mixed with chito-oligosaccharides (DP3-10) in Nicotiana glutinosa, and the virion structural change was studied by transmission electron microscopy after mixed with chito-oligosaccharides. In the range of tested concentrations of chito-oligosaccharides (100-1000 microg /mL), the numbers of local lesions were strongly reduced with over 30% decrement, and the 88.4% reduction gained at the concentration of 600g /mL. It revealed that treatment with chito-oligosaccharide solution of 300-500 microg /mL directly broke TMV particles into tiny pieces of 50-150nm long, and that treatment with solutions of 600-1000 microg/mL caused virus particle agglomerated. The data presented here suggested that chito-oligosaccharides exerted strong inactivating effect on plant virus in vitro.
Subject(s)
Microscopy, Electron, Scanning , Oligosaccharides , Pharmacology , Tobacco Mosaic Virus , VirionABSTRACT
HC-pro gene of Watermelon Mosaic virus was obtained by RT-PCR was 1371bp in length. It was cloned into pPI(9K, then the eucaryotic recombinant expression plasmid pPIC9K-WHC was constructed. After being linearized with restriction endonuclease Sal I , the recombinant plasmid was transformed into Pichia pastoris GS115 by electroporation. The high copy transformants with Mut+ /His+ phenotype were selected by RT-PCR and screening on G418, MD and MM medium. Induced by methanol for 5 days, the culture supernatant was analyzed by SDS-PAGE, the results showed that a specific protein with a molecular weight of about 66 kD was expressed. Western blot analysis proved that the expression protein could specifically bind to HC-Pro polyclonal antibody. Far western blot analysis proved that the expression protein could bind to coat protein, given support to "bridge" hypothesis that HC-Pro help aphid transmission of non-persistent viruses.