The claim of primacy of human gut Bacteroides ovatus in dietary cellobiose degradation.

A demonstration of cellulose degrading bacterium from human gut changed our view that human cannot degrade the cellulose. However, investigation of cellulose degradation by human gut microbiota on molecular level has not been completed so far. We showed here, using cellobiose as a model that promoted the growth of human gut key members, such as Bacteroides ovatus (BO), to clarify the molecular mechanism. Our results showed that a new polysaccharide utilization locus (PUL) from BO was involved in the cellobiose capturing and degradation. Further, two new cellulases BACOVA_02626GH5 and BACOVA_02630GH5 on the cell surface performed the degradation of cellobiose into glucose were determined. The predicted structures of BACOVA_02626GH5 and BACOVA_02630GH5 were highly homologous with the cellulase from soil bacteria, and the catalytic residues were highly conservative with two glutamate residues. In murine experiment, we observed cellobiose reshaped the composition of gut microbiota and probably modified the metabolic function of bacteria. Taken together, our findings further highlight the evidence of cellulose can be degraded by human gut microbes and provide new insight in the field of investigation on cellulose.

Influence of temperature and humidity on hand, foot, and mouth disease in Guangzhou, 2013-2017.

OBJECTIVE: To explore associations between temperature, humidity and hand, foot and mouth disease (HFMD) incidence in Guangzhou, China from 2013 to 2017. METHODS: A distributed lag non-linear model was applied to estimate the effects of daily temperature and humidity on HFMD incidence after adjusting for long-term trends, seasonal trends, and day of the week. RESULTS: In total, 353,431 confirmed HFMD cases were reported in Guangzhou over the study period. A bimodal seasonal pattern was observed. High temperatures had acute short-term effects on HFMD incidence that declined quickly over time. The effects of low humidity declined over lag periods, but increased when the humidity surpassed 60.5%. Temperature and humidity were both inversely associated with HFMD incidence during lag days 0 to 3 and with lag periods. CONCLUSIONS: Temperature and humidity play important roles in HFMD incidence. These data are important for developing public health strategies.

Loss-of-function mutations in Lysyl-tRNA synthetase cause various leukoencephalopathy phenotypes.

OBJECTIVE: To expand the clinical spectrum of lysyl-tRNA synthetase (KARS) gene-related diseases, which so far includes Charcot-Marie-Tooth disease, congenital visual impairment and microcephaly, and nonsyndromic hearing impairment. METHODS: Whole-exome sequencing was performed on index patients from 4 unrelated families with leukoencephalopathy. Candidate pathogenic variants and their cosegregation were confirmed by Sanger sequencing. Effects of mutations on KARS protein function were examined by aminoacylation assays and yeast complementation assays. RESULTS: Common clinical features of the patients in this study included impaired cognitive ability, seizure, hypotonia, ataxia, and abnormal brain imaging, suggesting that the CNS involvement is the main clinical presentation. Six previously unreported and 1 known KARS mutations were identified and cosegregated in these families. Two patients are compound heterozygous for missense mutations, 1 patient is homozygous for a missense mutation, and 1 patient harbored an insertion mutation and a missense mutation. Functional and structural analyses revealed that these mutations impair aminoacylation activity of lysyl-tRNA synthetase, indicating that defective KARS function is responsible for the phenotypes in these individuals. CONCLUSIONS: Our results demonstrate that patients with loss-of-function KARS mutations can manifest CNS disorders, thus broadening the phenotypic spectrum associated with KARS-related disease.

Willingness and influential factors of parents to vaccinate their children with novel inactivated enterovirus 71 vaccines in Guangzhou, China.

Hand, foot and mouth disease (HFMD) primarily affects children younger than 5 years of age. Recently, HFMD has ranked as the top notifiable infectious disease in China. In December 2015, China approved two novel inactivated enterovirus 71 vaccines (EV71 vaccines) for HFMD. Parents' acceptance is often essential for vaccination program success. The goal of this study was to identify willingness and influential factors to vaccinate among parents of kindergarteners in Guangzhou, China. A cross-sectional survey of face-to-face interviews was conducted from March to July 2016. Fifty-five kindergartens were randomly selected from 11 districts of Guangzhou. An anonymous self-designed questionnaire was used to investigate awareness, knowledge and attitude towards HFMD and EV71 vaccines. A total of 868 parents participated in the survey. Mean(±standard deviation) knowledge score of HFMD was 6.32(±1.70). Approximately 32.03% of parents had heard of the EV71 vaccines with 22.58% receiving information before this study. Nearly 44.24% of parents showed willingness to vaccinate their children. Previously receiving EV71 vaccine-related information [adjusted odds ratio (aOR) = 1.48, 95% confidence interval (CI): 1.04-2.11], no fear of adverse effects (aOR = 4.25, 95%CI: 2.77-6.53), perceived susceptibility of children to HFMD (aOR = 2.15, 95%CI: 1.42-3.25) and children not previously diagnosed with HFMD (aOR = 1.56, 95%CI: 1.07-2.27) were positively associated with EV71 vaccination acceptability. However, parental education background (aOR = 0.54, 95%CI: 0.37-0.80) was negatively correlated with vaccination acceptability. Our study provides baseline information for future vaccination campaigns to help improve the EV71 vaccine uptake rate. Special efforts are urgently needed to improve the awareness and knowledge of EV71 vaccines in China.