Unveiling lignin structures and lignin-carbohydrate complex (LCC) linkages of bamboo (Phyllostachys pubescens) fibers and parenchyma cells.

Bamboo (Phyllostachys pubescens) is an attractive biomass block to develop biorefining industry, however, less emphasis has been placed on elucidating the chemical linkage variations of lignin and LCC between different bamboo cell walls. Here, purified milled wood lignin (MWLp) and lignin-carbohydrate complex (LCC) were isolated from bamboo (Phyllostachys pubescens) fibers (BF) and parenchyma cells (PC), respectively. The variations of structure features and chemical linkages of lignin and LCC were investigated via FT-IR, 2D HSQC NMR, and 31P NMR techniques. 2D HSQC NMR revealed that ß-O-4 alkyl-aryl ether linkages and resinol (ß-ß) substructure were the main substructures in BF-MWLp and PC-MWLp. ß-1 linkages existed in the PC-MWLp (3.18/100 Ar), but not in BF-MWLp. Moreover, tricin, as a flavonoid compound, was only detected in the BF-MWLp. The amount of the syringyl (S) units of PC-MWLp was higher than BF-MWLp. The results indicated that phenyl glycoside (PhGlc) bonds (mainly lignin and xylan) were the predominant chemical linkage type of LCC bonds in BF-LCC and PC-LCC, and the high contents of PhGlc bonds (45.53/100 Ar) were presented in PC. Our finding can provide a reference for the structural variations of lignin and LCC between the different bamboo cell walls.

Association between Norovirus epidemics and school toilets design and management in Chengdu City / 中国学校卫生

Objective@#To analyze the relationship between the toilet design and sanitary condition of primary and secondary schools in Chengdu and the epidemic situation of Norovirus infection, so as to provide scientific references for school toilet design and Norovirus prevention and control.@*Methods@#A total of 78 cases of norovirus epidemics from 2019 to 2020 were included in this study. These epidemics happened in 78 schools and the causes were indicated as human-to-human transmission. The Chi square and Mann-Whitney U test were used to compare categorical and continuous data respectively. Unconditional binary Logistic regression was used to examine the multivariate associations.@*Results@#Most epidemics happened from October in 2019 to March in 2020(79.49%, 62 cases), in primary schools (71.79%, 56 cases) and in the center area (52.56%, 41 cases). The median of the case number in each epidemic was 10. Overall, 56 schools (71.79%) were equipped with toilets which were flushed independently, and 22 schools (28.21%) were equipped with toilets which were flushed uniformly. There were 27 schools (34.62%) that did not have enough water taps. Logistic regression analysis found that those with toilets flushed uniformly had a stronger epidemic, compared to the schools with toilets flushed independently( OR=5.53, 95%CI=1.63-18.76, P <0.05).@*Conclusion@#In order to prevent intestinal infectious diseases , it is suggested that schools should design or reconstruct independent flushing toilets with adequate faucets.

Associations of Hand-Foot-Mouth disease incidence among children of different age groups in kindergartens / 中国学校卫生

Objective@#To explore the associations of Hand-Foot-Mouth disease (HFM) among children of different age groups in kindergartens, and to provide scientific evidence for HFM prevention and control.@*Methods@#Cluster sampling was used to select 9 912 children from 40 kindergartens. The major caregivers of children were invited to participate into the study and fulfill a self-administered questionnaire that consisted of general background, hand washing and the history of HFM among children in the recent 1 year. Chi-square and binary logistic regression were applied,to analyze the influencing factors of HFM among children of different age groups.@*Results@#In the 2 year-old-group, children who were male (OR=1.76, 95%CI=1.24-2.50), had the major caregiver with high school educational background or below (OR=1.54, 95%CI=1.06-2.24), had family income more than 100 000 yuan or more per year(OR=1.49, 95%CI=1.01-2.20), children whose major caregiver seldom wash hands immediately after coming home(OR=2.10, 95%CI=1.05-4.19)，and 3-5 times per week(OR=2.07, 95%CI=1.26-3.41) were more likely to have HFM. In the 3 year-old-group, the more time children spent in the outdoors, the less likely they got HFM(3-5 times per week: OR=0.58, 95%CI=0.43-0.81; ≥6 times per week: OR=0.45, 95%CI=0.29-0.70). Children whose major caregiver did not use soap were more likely to have HFM(OR=1.67, 95%CI=1.11-2.49). In the 4 year-old-group, children who occasionally took toys when going out were less likely to get HFM (vs always, OR=0.57, 95%CI=0.38-0.88). No significant factors were found in the 5 year-old-group.@*Conclusion@#The behaviors and activities of major caregivers and children could influence the HFM incidence.To prevent HFM, it was advised that the major caregivers should wash hands immediately after coming home, and develop the habit of using soap for handwashing together with children at the earlier age, and encourage children to take more outside-door activities according to the age characteristics. Attention should be paid to avoid contaminating takeout snacks, and to clean the takeout toys timely.

Fabrication of antimicrobial composite films based on xylan from pulping process for food packaging.

A facile and green route is introduced to fabricate antimicrobial composite films in this article from xylan (XL) and hydroxyethyl cellulose (HEC) with citric acid (CA) and polyethylene glycol 400 (PEG-400) as crosslinker and plasticizer, respectively. XL was obtained by precipitating wood hydrolysate (WH) produced during pulping process with ethanol. Antimicrobial activity was constructed by incorporating ß-cyclodextrin/sodium benzoate (ß-CD/NaBz) complex into the composite matrix. The interactions, including hydrogen bonds and covalent bonds, between the polymers were confirmed by FT-IR spectroscopy. Morphology and crystallinity of composite films at different curing time were investigated by AFM and XRD, respectively. The composite film cured for 40 min exhibits tensile strength up to 62.3 MPa and oxygen permeability (OP) as low as 1.0 cm3·µm m-2·d-1·kPa-1. Finally, the antimicrobial test against Staphylococcus aureus reveals superior antimicrobial activity of composite films with complex. In conclusion, the XL/HEC antimicrobial film has great potential in the field of sustainable food packing materials.

Molecular characterization of enterovirus 71 sibling strains for thermal adaption in Vero cells with adaptive laboratory evolution.

Enterovirus 71 is the main pathogen that causes severe and fatal hand-foot-mouth-disease (HFMD) cases. As the enterovirus virus mutation has implications for pathogenesis, vaccine development, antiviral therapy, and epidemiological disease management of the virus. In this study, we investigated the variations of enterovirus 71 in thermal adaption, using the method of adaptive laboratory evolution. The sibling virus strains were isolated from a 2-year-old severe case of HFMD (#100) and her symptomless close contact (#101). Both strains were cultured in Vero cells by serial passage of 36 generations at the temperatures of 28.0 °C, 33.0 °C and 39.5 °C to construct adaptive lineages. According to the comparative analysis of phenotypes between adapted strains and parental strains, differences in growth rate were observed in the sibling lineages and a larger plaque was found mainly in the hot adapted strains for lineage #101. Two sets of adaptive strains from six time points (parental, 12th 17th, 31st, 35th passage and endpoint) were sequenced and analyzed by both Sanger sequencing and Next Generation Sequencing. Several variations in most coding genes and one reverse mutation in 5'UTR was observed, along with the identity of 99.8% for complete genome for both lineages. Notably, thermal specific non-synonymous mutations were found in the gene of VP1\VP3\3A\2C\3C. Moreover, the concurrent mutations A292G, A434G and A355C/T of sibling lineages in VP1 showed quantificational trace with distinguishing patterns for different temperatures, which were suspected to be the thermo-sensitive mutation hotspots. These results highlight the possible rules of thermal adaption in enterovirus 71, produce a novel picture of genome evolution of the virus, and shed light on viral variation and evolution.

Multiple transcriptional regulation of walnut JrGSTTau1 gene in response to osmotic stress.

Glutathione S-transferases (GSTs) are important plant proteins involved in biotic and abiotic stress responses. A gene from Juglans regia, JrGSTTau1 was previously cloned and functionally characterized as an enzyme involved in improving cold tolerance in plants. To clarify the functional mechanism of JrGSTTau1 and its role in stress response, here, the JrGSTTau1 promoter including the up-stream regulators was examined using yeast one-hybrid together with transient expression assays, and the osmotic stress response ability was confirmed by comparing with wild-type plants. The 1500 bp JrGSTTau1 promoter displayed high GUS expression activity and was enhanced by mannitol stress. The promoter is composed of abundant cis-elements, some of which were osmotic stress response-related motifs, such as ABRE, DRE and MYB, indicating that the expression of JrGSTTau1 is regulated by potential up-stream regulators under abiotic stress. The transcription factors (TFs) of JrDREB2A, JrMYC2, JrMYB44, JrDof1 and JrWRKY7 were identified, which shared a similar response with JrGSTTau1 when exposed to PEG6000 in walnut leaf and root. These results implied that JrDREB2A, JrMYC2, JrMYB44, JrDof1 and JrWRKY7 may act as up-stream regulators of JrGSTTau1 to regulate or combine functionality with JrGSTTau1 in osmotic stress response. Furthermore, compared with the WT plants, the transgenic tobacco plants that overexpress JrGSTTau1 showed improved tolerance to drought induced by osmotic stress, in which antioxidant enzymes, proline and reactive oxygen species (ROS) are involved. Our results demonstrated the positive role played by JrGSTTau1 in osmotic tolerance, which is regulated by multiple up-stream regulators.

Distribution of norovirus outbreaks and associated factors in Chengdu during 2017 / 中国学校卫生

Objective@#To analyze the features of Norovirus outbreaks in schools and kindergartens and the associated factors in Chengdu, 2017, and to provide the scientific basis for Norovious outbreaks prevention and control.@*Methods@#A total of 75 schools and kindergartens in Chengdu of 2017 participated in the study about Norovirus outbreaks. ANOVA and binary Logistic regression models were used to analyze the influencing factors and duration of Norovirus outbreaks.@*Results@#Overall 710 cases were included. There was an average of 9.47 cases and 27.52 hours for each outbreak,decreasing by 1.06 cases and 10.56 hours compared with those of 2016. Most outbreaks happened in kindergartens and in the firstlevel economy regions from January to March, with GII type as the main outbreak. Compared with the first case of vomiting at home, vomiting in public area (OR=11.76, 95%CI=1.63-84.69) was much more serious, and compared with the active report of school/ community, being informed of the outbreak passively (OR=4.09，95%CI=1.04-16.03) was positively associated with outbreak severity.@*Conclusion@#To prevent Norovirus infection, specific development and training of dealing with vomiting and feces should be introduced, and measures to increase the ability to surveil and report Norovirus outbreaks should be enhanced.