Assessment of efficiency of water supply system in Prince of Songkla University, Hat Yai Campus

Assessment of efficiency of water production system in Prince of Songkla University, Hat Yai Campus, was conducted in this study. Topics covered include 1) quality and quantity of raw water, 2) water productionprocess, 3) management and maintenance of water production system, and 4) quality of finished water. Totally, 494 water samples were collected during the study. All water samples were analyzed for turbidity,pH, temperature, conductivity, TDS, total coliforms, fecal coliforms and residual chlorine. In addition to the mentioned parameters, 30 of these water samples were also analyzed for hardness, chloride, nitratenitrogen,sulfate and heavy metals (manganese, copper, zinc, iron, chromium, cadmium, lead and mercury). All water samples were collected during November, 2004 (rainy season) and March, 2005 (summer season).It was found that the quality of the water in the Sritrang reservoir fell into Class 2 of Thailand Surface Water Quality Standard that requires ordinary water treatment processes prior to consumptions.Cadmium, lead and mercury were not detected by Inductively Coupled Plasma (ICP) method. There are 2 sets of water production system. The first set consists of 4 pressure filters which could reduce turbidity atvarying efficiencies: 33.83%, 18.26%, 42.76% and 65.67% depending mainly on the extent of chemical dosing control and the maintenance of the filter media. Another system employed sedimentation tank andrapid sand filter, which could remove turbidity at 89.28%. When combined finished water from both systems were analyzed, it was found that removals of manganese, copper, zinc, iron and chromium were 42.65%,30.02%, 19.54%, 56.82% and 15.12%, respectively. Residual chlorine concentration of the finished water was not more than 0.2 mg/L and no total coliforms or fecal coliforms were detected. The plant had sufficientand competent personnel to carry out their normal tasks but occasional negligence and lack of specific water testing or chemical dosing equipment were observed. The quality of tap water (in distribution system) isin compliance with the WHO drinking water quality standards, except occasionally turbidity and pH. Significant difference (p<0.05) in tap water quality was found between the samples collected in rainy and summer seasons

Multiplex Detection of Plant Pathogens Using a Microsphere Immunoassay Technology

Plant pathogens are a serious problem for seed export, plant disease control and plant quarantine. Rapid and accurate screening tests are urgently required to protect and prevent plant diseases spreading worldwide. A novel multiplex detection method was developed based on microsphere immunoassays to simultaneously detect four important plant pathogens: a fruit blotch bacterium Acidovorax avenae subsp. citrulli (Aac), chilli vein-banding mottle virus (CVbMV, potyvirus), watermelon silver mottle virus (WSMoV, tospovirus serogroup IV) and melon yellow spot virus (MYSV, tospovirus). An antibody for each plant pathogen was linked on a fluorescence-coded magnetic microsphere set which was used to capture corresponding pathogen. The presence of pathogens was detected by R-phycoerythrin (RPE)-labeled antibodies specific to the pathogens. The assay conditions were optimized by identifying appropriate antibody pairs, blocking buffer, concentration of RPE-labeled antibodies and assay time. Once conditions were optimized, the assay was able to detect all four plant pathogens precisely and accurately with substantially higher sensitivity than enzyme-linked immunosorbent assay (ELISA) when spiked in buffer and in healthy watermelon leaf extract. The assay time of the microsphere immunoassay (1 hour) was much shorter than that of ELISA (4 hours). This system was also shown to be capable of detecting the pathogens in naturally infected plant samples and is a major advancement in plant pathogen detection

Double mutations in eIF4E and eIFiso4E confer recessive resistance to Chilli veinal mottle virus in pepper

To evaluate the involvement of translation initiation factors eIF4E and eIFiso4E in Chilli veinai mottle virus (ChiVMV) infection in pepper, we conducted a genetic analysis using a segregating population derived from a cross between Capsicum annuum 'Dempsey' containing an eIF4E mutation (pvr1 2 ) and C. annuum 'Perennial' containing an eIFiso4E mutation (pvr6). C. annuum 'Dempsey' was susceptible and C. annuum 'Perennial' was resistant to ChiVMV. All F1 plants showed resistance, and F2 individuals segregated in a resistant-susceptible ratio of 166:21, indicating that many resistance loci were involved. Seventy-five F2 and 329 F3 plants of 17 families were genotyped with pvr1 2 and pvr6 allele-specific markers, and the genotype data were compared with observed resistance to viral infection. All plants containing homozygous genotypes of both pvr1 2 and pvr6 were resistant to ChiVMV, demonstrating that simultaneous mutations in eIF4E and eIFiso4E confer resistance to ChiVMV in pepper. Genotype analysis of F2 plants revealed that all plants containing homozygous genotypes of both pvr1 2 and pvr6 showed resistance to ChiVMV. In protein-protein interaction experiments, ChiVMV viral genome-linked protein (VPg) interacted with both eIF4E and eIFiso4E. Silencing of eIF4E and eIFiso4E in the VIGS experiment showed reduction in ChiVMV accumulation. These results demonstrated that ChiVMV can use both eIF4E and eIFiso4E for replication, making simultaneous mutations in eIF4E and eIFiso4E necessary to prevent ChiVMV infection in pepper. © 2009 The Korean Society for Molecular and Cellular Biology and Springer Netherlands

Conformationally Gated Charge Transfer in DNA Three-Way Junctions

Molecular structures that direct charge transport in two or three dimensions possess some of the essential functionality of electrical switches and gates. We use theory, modeling, and simulation to explore the conformational dynamics of DNA three-way junctions (TWJs) that may control the flow of charge through these structures. Molecular dynamics simulations and quantum calculations indicate that DNA TWJs undergo dynamic interconversion among “well stacked” conformations on the time scale of nanoseconds, a feature that makes the junctions very different from linear DNA duplexes. The studies further indicate that this conformational gating would control charge flow through these TWJs, distinguishing them from conventional (larger size scale) gated devices. Simulations also find that structures with polyethylene glycol linking groups (“extenders”) lock conformations that favor CT for 25 ns or more. The simulations explain the kinetics observed experimentally in TWJs and rationalize their transport properties compared with double-stranded DNA