[Chemotactic response of ginseng endophyte to ginseng root exudates].

The ginseng endophytic bacteria F1 is a potential biocontrol agent for ginseng bacterial soft rot. In this paper,the chemotactic response of ginseng endophytic bacteria F1 on 8 kinds of sugar and amino acids was detected by capillary method to explore its biocontrol mechanism. The chemotactic response of F1 strain to 4 kinds of better chemotaxis substances such as glucose,glycine,L-rhamnoseand L-glutamic acid under parameters( concentration,time,temperature and pH) was studied. The results showed that under the same experimental conditions( incubation temperature 25 ℃,incubation time 60 min,chemotaxis concentration 1 mg·L~(-1)),ginseng endophytic bacteria F1 showed different degrees of response to the eight substances tested. The phenomenon of positive chemotaxis of the measured sugars and amino acids was obvious,and the chemotactic response to total ginsenosides was low. The degree of chemotaxis response is positively correlated with the chemotaxis index within a certain range of parameters,but as the temperature,p H,time,concentration and other factors continue to increase,the chemotaxis effect decreases,and F1 optimizes the chemotaxis of the four substances. The parameters are as follows: glucose: 25 ℃,10 mg·L~(-1),45 min,pH 7; glycine: 30 ℃,10 mg·L~(-1),75 min,pH7; L-rhamnose: 30 ℃,1 mg·L~(-1),30 min,pH 6; L-glutamic acid: 25 ℃,0. 1 mg·L~(-1),45 min,pH 8. The chemotactic response is more sensitive to low concentrations of chemotactic substances.

Prevalence of cervicovaginal human papillomavirus infection and genotypes in the pre-vaccine era in China: A nationwide population-based study.

OBJECTIVE: The HPV vaccine has been licensed in mainland China since 2017. This study aimed to assess the epidemiological characteristics of HPV genotypes in the pre-vaccine era in China. METHODS: We conducted a multicentric population-based study nested in the largest health clinic chain in China. Between January 1, 2017 and December 31, 2017, 427,401women aged 20 years or older with polymerase chain reaction-based HPV genotyping tests were included in the study. The cervicovaginal infection of 14 high-risk HPV genotypes and 9 low-risk genotypes was assessed using adjusted prevalence, multivariable logistic regression, cluster analysis, and heatmap. RESULTS: HPV prevalence was 15.0% (95% confidence interval [CI]: 14.1-15.9%) in China, with high- and low-risk genotypes being 12.1% (95%CI: 11.4-12.7%) and 5.2% (95%CI: 4.8-5.7%), respectively. The prevalence of HPV genotypes corresponding to bivalent, quadrivalent, and nonavalent vaccines were 2.1%, 2.4%, and 8.3%, respectively, whereas the prevalence of non-vaccine high-risk genotypes was 5.7%. The most common high-risk genotypes were HPV-52 (3.5%), HPV-58 (2.1%), and HPV-16 (1.6%), and the prevalence of HPV-18 (0.6%), HPV-6 (0.1%), and HPV-11 (0.2%) were relatively low. Infection with HPV genotypes differed significantly across age groups and geographic locations. CONCLUSION: HPV prevalence was high in the pre-vaccine era in China, and a population-based HPV vaccination strategy is needed in the future.