Responses of unsaturated Pseudomonas putida CZ1 biofilms to environmental stresses in relation to the EPS composition and surface morphology.

The extracellular polymeric substance (EPS) and surface properties of unsaturated biofilms of a heavy metal-resistant rhizobacterium Pseudomonas putida CZ1, in response to aging, pH, temperature and osmotic stress, were studied by quantitative analysis of EPS and atomic force microscope. It was found that EPS production increased approximately linearly with culture time, cells in the air-biofilm interface enhanced EPS production and decreased cell volume to cope with nutrient depletion during aging. Low pH, high temperature and certain osmotic stress (120 mM NaCl) distinctly stimulated EPS production, and the main component enhanced was extracellular protein. In addition to the enhancement of EPS production in response to high osmotic (328 mM NaCl) stress, cells in the biofilm adhere tightly together to maintain a particular microenvironment. These results indicated the variation of EPS composition and the cooperation of cells in the biofilms is important for the survival of Pseudomonas putida CZ1 from environmental stresses in the unsaturated environments such as rhizosphere.

Health-adjusted life expectancy (HALE) in Chongqing, China, 2017: An artificial intelligence and big data method estimating the burden of disease at city level.

BACKGROUND: A universally applicable approach that provides standard HALE measurements for different regions has yet to be developed because of the difficulties of health information collection. In this study, we developed a natural language processing (NLP) based HALE estimation approach by using individual-level electronic medical records (EMRs), which made it possible to calculate HALE timely in different temporal or spatial granularities. METHODS: We performed diagnostic concept extraction and normalisation on 13•99 million EMRs with NLP to estimate the prevalence of 254 diseases in WHO Global Burden of Disease Study (GBD). Then, we calculated HALE in Chongqing, 2017, by using the life table technique and Sullivan's method, and analysed the contribution of diseases to the expected years "lost" due to disability (DLE). FINDINGS: Our method identified a life expectancy at birth (LE0) of 77•9 years and health-adjusted life expectancy at birth (HALE0) of 71•7 years for the general Chongqing population of 2017. In particular, the male LE0 and HALE0 were 76•3 years and 68•9 years, respectively, while the female LE0 and HALE0 were 80•0 years and 74•4 years, respectively. Cerebrovascular diseases, cancers, and injuries were the top three deterioration factors, which reduced HALE by 2•67, 2•15, and 1•19 years, respectively. INTERPRETATION: The results demonstrated the feasibility and effectiveness of EMRs-based HALE estimation. Moreover, the method allowed for a potentially transferable framework that facilitated a more convenient comparison of cross-sectional and longitudinal studies on HALE between regions. In summary, this study provided insightful solutions to the global ageing and health problems that the world is facing. FUNDING: National Key R and D Program of China (2018YFC2000400).

Cr(VI) reduction by an extracellular polymeric substance (EPS) produced from a strain of Pseudochrobactrum saccharolyticum.

A better understanding of the Cr(VI) reduction position and mechanisms by a Cr(VI)-reducing strain is important for the bioremediation of Cr pollution in the environment. In the present study, we were interested in figuring out the role of extracellular polymeric substances (EPS) as the main area for Cr(VI) reduction in the newly reported strain of Pseudochrobactrum saccharolyticum LY10. We investigated the subcellular distribution and reduction capability of each cellular component as the main area of Cr(VI) reduction by scanning electron microscopy and soft X-ray spectromicroscopy. The results suggested that most of Cr was presented in the supernatants as Cr(III) after reduction. In the cells, Cr was mostly distributed in the EPS and cell wall, while the EPS had the maximum Cr(VI) reduction rate (81.5%) as compared with the cell wall (30.1%). Soft X-ray spectromicroscopy analysis indicated that Cr accumulated more in the EPS. Therefore, the results suggested that the EPS were the main area for Cr(VI) reduction in the bacteria of P. saccharolyticum LY10.

Forecasting influenza activity using self-adaptive AI model and multi-source data in Chongqing, China.

BACKGROUND: Early detection of influenza activity followed by timely response is a critical component of preparedness for seasonal influenza epidemic and influenza pandemic. However, most relevant studies were conducted at the regional or national level with regular seasonal influenza trends. There are few feasible strategies to forecast influenza activity at the local level with irregular trends. METHODS: Multi-source electronic data, including historical percentage of influenza-like illness (ILI%), weather data, Baidu search index and Sina Weibo data of Chongqing, China, were collected and integrated into an innovative Self-adaptive AI Model (SAAIM), which was constructed by integrating Seasonal Autoregressive Integrated Moving Average model and XGBoost model using a self-adaptive weight adjustment mechanism. SAAIM was applied to ILI% forecast in Chongqing from 2017 to 2018, of which the performance was compared with three previously available models on forecasting. FINDINGS: ILI% showed an irregular seasonal trend from 2012 to 2018 in Chongqing. Compared with three reference models, SAAIM achieved the best performance on forecasting ILI% of Chongqing with the mean absolute percentage error (MAPE) of 11·9%, 7·5%, and 11·9% during the periods of the year 2014-2016, 2017, and 2018 respectively. Among the three categories of source data, historical influenza activity contributed the most to the forecast accuracy by decreasing the MAPE by 19·6%, 43·1%, and 11·1%, followed by weather information (MAPE reduced by 3·3%, 17·1%, and 2·2%), and Internet-related public sentiment data (MAPE reduced by 1·1%, 0·9%, and 1·3%). INTERPRETATION: Accurate influenza forecast in areas with irregular seasonal influenza trends can be made by SAAIM with multi-source electronic data.

Influence of heavy metals and PCBs pollution on the enzyme activity and microbial community of paddy soils around an e-waste recycling workshop.

Due to the emerging environmental issues related to e-waste there is concern about the quality of paddy soils near e-waste workshops. The levels of heavy metals and PCBs and their influence on the enzyme activity and microbial community of paddy soils obtained from the immediate vicinity of an e-waste workshop were investigated in the present study. The results indicated that the heavy metal and PCB pollution did not differ significantly with an increase of the sampling point distances (5 to 30 m). The concentration of Cd (2.16 mg·kg-1) and Cu (69.2 mg·kg-1) were higher, and the PCB pollution was also serious, ranging from 4.9 to 21.6 µg·kg-1. The highest enzyme activity was found for urease compared to phosphatase and catalase, and a fluctuating trend in soil enzyme activity was observed in soils from different sampling sites. The microbial analysis revealed that there was no apparent correlation between the microbial community and the pollutants. However, a slight influence for soil microbial communities could be found based on DGGE, the Shannon index and PCA analysis. The present study suggests that the contamination stress of heavy metals and PCBs might have a slight influence on microbial activity in paddy soils. This study provides the baseline data for enzyme activities and microbial communities in paddy soil under the influence of mixed contamination.

Cr(VI) reduction by a potent novel alkaliphilic halotolerant strain Pseudochrobactrum saccharolyticum LY10.

A novel Cr(VI)-reducing strain, Pseudochrobactrum saccharolyticum LY10, was isolated and characterized for its high Cr(VI)-reducing ability. Strain LY10 had typical characteristics of alkali-tolerance and halotolerance. Kinetic analysis indicated that the maximum reduction rate was achieved under optimum conditions with initial pH 8.3, 20gL(-1) NaCl, 55mgL(-1) Cr(VI), and 1.47×10(9)cellsmL(-1) of cell concentration. Further mechanism studies verified that the removal of Cr(VI) was mainly achieved by a metabolism-dependent bioreduction process. Strain LY10 accumulated chromium both in and around the cells, with cell walls acting as the major binding sites for chromium. X-ray absorption near-edge structure (XANES) analysis further confirmed that the chromium immobilized by the cells was in the Cr(III) state. In the present study, Pseudochrobactrum saccharolyticum was, for the first time, reported to be a Cr(VI)-reducing bacteria. Results from this research would provide a potential candidate for bioremediation of Cr(VI)-contaminated environments, especially alkaline and saline milieus with Cr(VI) at low-to-mid concentrations.

Cr(VI) resistance and removal by indigenous bacteria isolated from chromium-contaminated soil.

The removal of toxic Cr(VI) by microorganisms is a promising approach for Cr(VI) pollution remediation. In the present study, four indigenous bacteria, named LY1, LY2, LY6, and LY7, were isolated from Cr(VI)-contaminated soil. Among the four Cr(VI)-resistant isolates, strain LY6 displayed the highest Cr(VI)-removing ability, with 100 mg/l Cr(VI) being completely removed within 144 h. It could effectively remove Cr(VI) over a wide pH range from 5.5 to 9.5, with the optimal pH of 8.5. The amount of Cr(VI) removed increased with initial Cr(VI) concentration. Data from the time-course analysis of Cr(VI) removal by strain LY6 followed first-order kinetics. Based on the 16S rRNA gene sequence, strain LY6 was identified as Pseudochrobactrum asaccharolyticum, a species that had never been reported for Cr(VI) removal before. Transmission electron microscopy and energy dispersive X-ray spectroscopy analysis further confirmed that strain LY6 could accumulate chromium within the cell while conducting Cr(VI) removal. The results suggested that the indigenous bacterial strain LY6 would be a new candidate for potential application in Cr(VI) pollution bioremediation.

[Persisters and their effects on microbial biofilm tolerance: a review].

Persisters are a group of special subpopulation of bacteria, only occupying < 0.1% of the whole population but having the characteristics different from the ordinary bacteria and resistant mutants. They have complex formation mechanism, and are difficult to isolate and culture. The persisters can adapt to the adverse environment via "dormancy-growth-proliferation" to maintain their survival and cell structure stability, and play a vital role in the multi-drug and multi-metal tolerance of microbial biofilm, being of great significance in maintaining the stability of microbial community structure. This paper reviewed the research progress on the characteristics of persisters, their gene regulation mechanisms, and their effects on the multi-drug and multi-metal tolerance of microbial biofilm. The related research directions in the future were also prospected.