Comparative analysis of the gut microbiota of wild adult rats from nine district areas in Hainan, China.

BACKGROUND: Wild rats have the potential to hold zoonotic infectious agents that can spread to humans and cause disease. AIM: To better understand the composition of gut bacterial communities in rats is essential for preventing and treating such diseases. As a tropical island located in the south of China, Hainan province has abundant rat species. Here, we examined the gut bacterial composition in wild adult rats from Hainan province. METHODS: Fresh fecal samples were collected from 162 wild adult rats, including three species (Rattus norvegicus, Leopoldamys edwardsi, and Rattus losea), from nine regions of Hainan province between 2017-2018. RESULTS: We analyzed the composition of gut microbiota using the 16S rRNA gene amplicon sequencing. We identified 4903 bacterial operational taxonomic units (30 phyla, 175 families, and 498 genera), which vary between samples of different rat species in various habitats at various times of the year. In general, Firmicutes were the most abundant phyla, followed by Bacteroidetes (15.55%), Proteobacteria (6.13%), and Actinobacteria (4.02%). The genus Lactobacillus (20.08%), unidentified_Clostridiales (5.16%), Romboutsia (4.33%), unidentified_Ruminococcaceae (3.83%), Bacteroides (3.66%), Helicobacter (2.40%) and Streptococcus (2.37%) were dominant. CONCLUSION: The composition and abundance of the gut microbial communities varied between rat species and locations. This work provides fundamental information to identify microbial communities useful for disease control in Hainan province.

Stopped-Flow Dynamics Study on the Escape Behavior of Polyelectrolyte Macromolecules from Microgels: The Influence of the Path Length and Size.

We reported the fabrication of several monodispersed poly(2-vinyl pyridine)-poly(N-isopropylacrylamide) (P2VP-PNIPAM) microgels including the P2VP core (non-cross-linked) and PNIPAM (cross-linked) shell by mature emulsion polymerization. The fast escape behavior (diffusion process) of linear P2VP chains through a porous PNIPAM layer was investigated by a pH jump stopped-flow apparatus. The time-dependent dynamic traces (corresponding to the scattered light intensity) decreased at the initial timescale of several seconds and then reached an apparent equilibrium, confirming the efficient escape of P2VP chains from microgels. Compared with the previously reported literature, such an accelerated escape process resulted from the sharply increased internal charge repulsive force caused by the protonation of P2VP moieties under acidic conditions. The obtained characteristic relaxation times by single exponential fitting of these kinetic traces were dependent on the final pH values, equilibrium temperatures, shell thickness (path length), and cross-linking density (mesh size). We believe that this work can provide an efficient way to investigate hindered diffusion, especially the initial rapid diffusion stage. Not only that, the proposed model can also provide theoretical guidance to some practical applications, such as membrane separation and the exocytosis phenomenon of intracellular proteins or macromolecular substances.

[Application of PulseNet China Database in tracking and warning 4 cholerae outbreaks in Anhui province, in 2012].

OBJECTIVE: To track the source of infection regarding 4 Cholerae outbreaks in Anhui province in 2012 through the application of PulseNet China Database (PNCD). METHODS: Cholerae virulence genes were amplified by PCR and typed by pulse field gel electrophoresis(PFGE). Results from electrophoresis were cluster-analyzed by BioNumericsV4.0 software and compared with PNCD. RESULTS: Virulence gene CT and TCP of the tested vibrio cholera showed both positive. Homology of the strains from four cholera outbreaks was more than 98%, based on the homologous and cluster analysis through enzyme digested PFGE electrophoresis. Those strains were highly homologous with the cholera epidemic strains identified in Hunan, Sichuan,Zhejiang, Shanghai and Hubei by PNCD, with the homology as 100% . CONCLUSION: Four cholera outbreaks in Anhui province, 2012 were highly correlated with the outbreaks occurring in Hunan and Sichuan during the same time period, indicating that PNCD could effectively and quickly tracking down the source of infection on the cholera outbreaks and providing early warning of the situation.

[The firstly confirmed pregnant woman case of avian influenza A (H5N1) by etiological research in China].

To investigate the cause of death of a pregnant woman with undefined pneumonia reported from the People's Hospital of Tongling City in Anhui Province on November 8, 2005, the patient's tracheal aspirates and serum samples were collected and tested by RT-PCR and Real-time PCR to detect viral nucleic acids of HA of A/H5N1, A/H7N7, A/H9N1 and A/M. Tracheal aspirates were inoculated into special pathogen free (SPF) embryonated eggs for cultivation and identification of virus. The HA gene of the virus was sequenced and analyzed. Serum samples were tested by HI assay to detect antibody of H5N1. The results showed that HA gene of A/H5N1 virus and A/M were positive in tracheal aspirates by both PCR tests. The serum sample collected on Nov. 9 was A/M gene positive by Real-time PCR. The analysis of HA gene of A/AnHui/1/2005 sequence showed that the receptor specificity and the connecting peptide between HA1 and HA2 were still avian influenza origin. The HI antibody of H5N1 was negative at 7th, 8th, 9th d of disease onset. This undefined pneumonia case was confirmed as the first pregnant woman case of avian influenza (H5N1) virus infection by etiology in the mainland of China.

[Study on a fatal pregnant woman died from by avian influenza (H5N1)].

OBJECTIVE: To ascertain the causation of a pregnant woman with undefined pneumonia reported from the People's Hospital of Tongling city in Anhui province on November 2005. METHODS: Epidemiological and clinical information of the case was collected from the keypersons close to the case and referring to the medical record. A medical observation was carried out on the close contacts of the case and sick or dead poultry. Tracheal aspirates being collected were tested by both RT-PCR and real-time PCR to detect viral nucleic acids of A/H5N1, and were inoculated into special pathogen free (SPF) embryonated hens' eggs. RESULTS: The pregnant woman was found to have been contacted with the sick/dead poultry directly on the 4th day before onset of illness. All the 122 close contacts were healthy after a 10-day medical observation. The major clinical features of the case were viral pneumonia with rapidly developed leukopenia and lymphopenia. The progress to acute respiratory distress syndrome and multiple organ dysfunction syndromes was found at clinical presentation. HA and NA gene of A/H5N1 virus were positive. The 8 gene fragments of A/Anhui/1/2005 (H5N1) isolated from the tracheal aspirates had not carried genes from a human virus through reassortment, and the receptor-binding site of the hemagglutinin was polybasic cleavage site. CONCLUSION: This was the first documented case of H5N1 infection in pregnant woman. The immunotolerant state of pregnancy might have predisposed to the fatal outcome of the patient.