The suppressive effect of MiR-490 on coxsackievirus B3 replication / 病毒学报

To study the effect of miR-490 on Coxsackievirus B3 (CVB3) replication, HeLa cells were trans- fected with miR-490 in vitro, and infected with a Renilla luciferase (RLuc)-expressing CVB3 variant (RLuc-CVB3). The activities of RLuc in these cells were measured at 8h intervals from 0 to 40 h post-infection (p.i.), and the effects of miR-490 on RLuc-CVB3 replication were observed. In a further study, HeLa cells were transfected with either miR-490 or antisense miR-490 (AMO-miR-490), and were then infected with an enhanced green fluorescence protein (EGFP)-expressing CVB3 variant (EGFP-CVB3). The replication of EGFP-CVB3 was then determined by detecting the expression of EGFP. We observed that miR-490 could significantly inhibit the expression of RLuc in infected cells at 32 h p. i. Furthermore, in HeLa cells infected with EGFP-CVB3 at 32 h p.i., EGFP expression was also significantly inhibited by the presence of mniR-490. The inhibitory effect of miR-490 on EGFP expression in EGFP-CVB3-infected cells could be reversed by tranfection with AMQ-miR-490. These results indicated that miR-490 significantly inhibits the replication and expression of QVB3.

Effect of mutations in the 5'untranslated region pyrimidine-rich tract on the virulence variation of coxsackievirus B1 / 中国地方病学杂志

Objective To evaluate the infectivity and virulence variation caused by mutations in the 5' untranslated region(5'UTR)pyrimidine-rich tract of coxsackievirus B1(CVB1)genome.Methods Five pyrimidines in the 5'UTR pyrimidine-rich tract(nt563-nt573)of CVB1 genome were substituted with purines by site-directed mutagenesis.The mutant,CVB1/m563-573,was purified by plaque assay,and subjected to infectivity and virulence assessments by means of cytopathic effect(CPE),plaque forming,one-step growth curve,and 50% lethal dose(LD50)assays.Results Sequencing data revealed that the sequence of pyrimidine-rich tract in the 5'UTR of CVB1/m563-573 mutant was exactly identical to our design(C565A,U567C,U568A,U570A,and U572G).CPE assay showed that the infectivity of CVB1/m563-573 was weaker than that of its prototype CVB1/wt(A490=0.710±0.074,0.812±0.092)though no significant difference could be observed(t=-2.204,P>0.05).Plaque forming assay showed that the plaque quantities of CVB1/m563-573 were(6.40±1.52)×103,(11.60±2.19)×103 pfu/L and the plaque diameters of CVB1/m563-573 were(2.00±0.35),(2.47±0.41)mm at 46 and 58 hours pestinfection,respectively.The plaque quantities of CVB1/wt were(8.40±2.51)×103,(11.80±1.92)×103 pfu/L and the plaque diameters of CVB1/wt were(1.80±0.27),(2.85±0.44)mm,respectively.There was no significant difference between the plaque quantities and sizes of CVB1/m563-573 and CVB1/wt(t=8.000,0.985,10.000,9.000,all P>0.05).One-step growth curve demonstrated that the numbers(lg)of CVB1/m563-573 progenies at time-points of 3,5,7 h postinfection were 2.10±0.09,4.28±0.03,7.44±0 and that of CVB1/wt progenies were 2.80±0.02,4.77±0.02,8.55±0.01,respectively.The replication of CVB1/m563-573 was significantly slower than that of CVB1/wt at all three time-points(t=-13.151,-24.319,-47.714,all P<0.01).The LD50 of CVB1/m563-573(3.10×109 pfu/L)and CVB1/wt(1.26×107 pfu/L)indicated that the virulence of CVB1/m563-573 was significantly weakened compared to that of CVB1/wt.Conclusions The infectivity and virulence of CVB1 are weakened by substitution of pyrimidines with purines in the pyrimidine-rich tract of CVB1 5'UTR.Site-directed mutagenesis in the pyrimidine-rich tract may be a strategy for developing attenuated CVB vaccine.

Application of nano-sized TiO2 photocatalysis to air purification and sterilization / 中华预防医学杂志

<p><b>OBJECTIVE</b>To develop and evaluate the efficiency of air purification and sterilization instrument based on nano-sized TiO(2) photocatalytic technique.</p><p><b>METHODS</b>The nano-sized TiO(2) photocatalytic air purification and sterilization instrument was designed and a sample had been prepared. The sterilization efficiencies for E.coli and Klebsiella by the nano-sized TiO(2) photocatalytic instrument and ultraviolet (UV) were measured in closed labs. The on-site efficiency of the instrument was evaluated, too.</p><p><b>RESULTS</b>The nano-sized TiO(2) photocatalytic air purification and sterilization instrument was composed of five units: rough filter, nano-sized TiO(2) photocatalytic unit, activated carbon fiber filter, negative ion generator, and programmed control unit. The E.coli killing rates by the nano-sized TiO(2) photocatalytic instrument were 76.0%, 81.8%, 77.5%, and 80.7% at 30, 60, 90, and 120 minutes, respectively. There was no significant difference between the E.coli killing rates of the instrument and UV (P > 0.05), except the 120 minutes timepoint. The Klebsiella killing rates by the instrument were 78.4%, 79.5%, 67.3%, and 58.5% at 30, 60, 90, and 120 minutes, respectively. The Klebsiella killing efficiencies of the instrument at 30 and 60 minutes were better than that of UV (P < 0.01). There was no significant difference between the Klebsiella killing efficiencies of the instrument and UV (P > 0.05).</p><p><b>CONCLUSION</b>The air sterilization efficiency of the nano-sized TiO(2) photocatalytic instrument should be equivalent or better as compared with the UV. This instrument might be used for the air purification and sterilization of the public locations.</p>