Two Marine Desulfotomaculum spp. of Different Origin are Capable of Utilizing Acetone and Higher Ketones

Distribution of corrosive microbial communities in rust layers of steel immersed in seawater

In this paper, high-throughput sequencing technology was adopted to visualize the microbial communities on the surfaces of two types of carbon steel immersed in Sea Area Ⅰ. The results showed that different microbial communities were formed on different carbon steel surfaces, in which the genus with the highest abundance on the surface of Q235 was Escherichia-Shigella, while anaerobic Desulfovibrio on the surface of 921a was the most abundant, and the dominant genus varied with the depth of the rust layer. In addition, the distribution of sulfate-reducing bacteria (SRB) on the surface of Q235 submerged in Sea Area Ⅱ was compared with the sulfate-reducing bacteria's distribution in Sea Area Ⅰ, using the environmental factors correlation analysis. The results showed that the concentrations of Ca2+, Na+, K+, Mg2+, and Al3+ were positively correlated with the distribution of SRB, while the concentrations of Cu2+, Zn2+, SO4 2-, Cl-, NO3 -, and organic carbon were negatively correlated with it. Furthermore, there was a highly significant correlation between each geochemical factor and Desulfotomaculum (p < 0.01).

Sustainability of the rice-crayfish co-culture aquaculture model: microbiome profiles based on multi-kingdom analyses

While the rice-crayfish culture (RCFP) model, an important aquaculture model in Asia, is generally considered a sustainable model, its sustainability in terms of microbial community profiles has not been evaluated. In this study, multi-kingdom analyses of microbiome profiles (i.e., bacteria, archaea, viruses, and eukaryotes) were performed using environmental (i.e., water and sediment) and animal gut (i.e., crayfish and crab gut) microbial samples from the RCFP and other aquaculture models, including the crab-crayfish co-culture, crayfish culture, and crab culture models, to evaluate the sustainability of the RCFP systematically. Results showed that RCFP samples are enriched with a distinct set of microbes, including Shewanella, Ferroplasma, Leishmania, and Siphoviridae, when compared with other aquaculture models. Additionally, most microbes in the RCFP samples, especially microbes from different kingdoms, were densely and positively connected, which indicates their robustness against environmental stress. Whereas microbes in different aquaculture models demonstrated moderate levels of horizontal gene transfer (HGT) across kingdoms, the RCFP showed relatively lower frequencies of HGT events, especially those involving antibiotic resistance genes. Finally, environmental factors, including pH, oxidation-reduction potential, temperature, and total nitrogen, contributed profoundly to shaping the microbial communities in these aquaculture models. Interestingly, compared with other models, the microbial communities of the RCFP model were less influenced by these environmental factors, which suggests that microbes in the latter have stronger ability to resist environmental stress. The findings collectively reflect the unique multi-kingdom microbial patterns of the RCFP model and suggest that this model is a sustainable model from the perspective of microbiome profiles.