Metagenomic analysis reveals wide distribution of phototrophic bacteria in hydrothermal vents on the ultraslow-spreading Southwest Indian Ridge.

Deep-sea hydrothermal vents are known as chemosynthetic ecosystems. However, high temperature vents emit light that hypothetically can drive photosynthesis in this habitat. Metagenomic studies have sporadically reported the occurrence of phototrophic populations such as cyanobacteria in hydrothermal vents. To determine how geographically and taxonomically widespread phototrophs are in deep-sea hydrothermal vents, we collected samples from three niches in a hydrothermal vent on the Southwest Indian Ridge and carried out an integrated metagenomic analysis. We determined the typical community structures of microorganisms found in active venting fields and identified populations of known potential chlorophototrophs and retinalophototrophs. Complete chlorophyll biosynthetic pathways were identified in all samples. By contrast, proteorhodopsins were only found in active beehive smoker diffusers. Taxonomic groups possessing potential phototrophy dependent on semiconductors present in hydrothermal vents were also found in these samples. This systematic comparative metagenomic study reveals the widespread distribution of phototrophic bacteria in hydrothermal vent fields. Our results support the hypothesis that the ocean is a seed bank of diverse microorganisms. Geothermal vent light may provide energy and confer a competitive advantage on phototrophs to proliferate in hydrothermal vent ecosystems. Supplementary Information: The online version contains supplementary material available at 10.1007/s42995-021-00121-y.

A new flexible titanium foil cell for hydrothermal experiments and fluid sampling.

This paper describes the design of a flexible titanium foil cell, as well as its applications in hydrothermal experiments and in non-contaminating storage of seafloor hydrothermal fluids. A flexible cell constructed totally from pure titanium (Grade 1) can be used in corrosive environment because of the excellent chemical stability and temperature tolerance of the material. Theoretical calculation and finite element analysis of the titanium foil cell have been conducted to identify its flexibility and deformation mode. Two applications, i.e., hydrothermal reaction and non-contaminating fluid sampling, were introduced subsequently. The flexible titanium foil cell was successfully tested at elevated temperature and pressure of up to 400 °C and 40 MPa, respectively, demonstrating that it could be widely used under supercritical water conditions.

[Analysis on the risk factors of severe acute respiratory syndromes coronavirus infection in workers from animal markets].

OBJECTIVE: To investigate the possible risk factors of severe acute respiratory syndromes coronavirus (SARS-CoV) infection in workers from animal markets. METHODS: Self-designed questionnaires were used and serum samples were tested. Logistic regression analysis was used to analyze the data. RESULTS: Results from simple factor logistic regression analysis showed that jobs which dealing with domestic livestock, wild livestock, wild animals, aquatics were related to risk factors of SARS-CoV infection. Results from multifactor logistic regression analysis showed that jobs that dealing with wild livestock and poultry were important risk factors with OR 12.28 and 0.41. CONCLUSION: Job that dealing with palm civets was the main risk factor of SARS-CoV infection in animal market workers.

[An epidemiologic investigation on infection with severe acute respiratory syndrome coronavirus in wild animals traders in Guangzhou].

OBJECTIVE: To investigate status of infection with severe acute respiratory syndrome coronovirus (SARS-CoV) in traders of wild animals wholesale markets in Guangzhou. METHODS: Serum antibody against SARS-CoV IgG was determined cross-sectionally and symptoms of respiratory infection were investigated retrospectively for part of traders of three wholesale markets for wild animals in Guangzhou. RESULTS: Overall rate of infection with SARS-CoV in 635 traders was 16.69%, varying in three different markets. Infection rate in market A mainly engaging in wild animals ranked the highest of 25.61%, significantly higher than that in markets B and C engaging in domestic fowls and snakes. Infection rate in traders only engaging in civet cats was 58.54%, significantly higher than that in traders engaging in snakes only (9.46%). In market A, infection rate varied in different persons, 59.34%, 20.59%, 16.00%, 15.22%, 10.40% and 9.68% in traders engaging in wild animals, managers, children of the traders, traders engaging in domestic fowls, traders engaging in snakes, and traders engaging in frozen food, respectively, in a decreasing pattern as their contact opportunities. During the period of SARS epidemic, detection rate of SARS-CoV antibody in people with symptoms of acute respiratory infection was higher (30.70%) than that in those without such symptoms (20.08%). Prevalence of symptoms of acute upper respiratory infection in people with positive antibody against SARS-CoV was higher (49.28%) than that in those with negative antibody (30.35%). CONCLUSIONS: Infection with SARS-CoV in traders of animal markets possibly related to their direct exposure to wild animals, particularly to civet cats. During the period of SARS epidemic, some of the traders did infect with SARS-CoV, but they were neglected due to clinically inapparent manifestations.