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In this study, a yeast strain with an outstanding NH3-N degradation ability was isolated from the sediment of a black-odor water channel in Guangdong Province, China. Based on phenotypic and phylogenetic analysis, this strain was identified as Pichia kudriavzevii GW1. The optimum conditions for NH3-N degradation by the GW1 strain were as follows: 0.3% inoculum concentration, 1.5 L/min aeration, pH 7, and a temperature of 35°C. Under optimized conditions, the GW1 strain degraded 95.5% of the NH3-N. The strain was then added to simulated black-odor water under optimal degradation conditions to investigate changes to the bacterial community over time. 16S rRNA sequencing of samples collected on days 0, 7, 14, and 21 showed that, in the presence of the GW1 strain, the relative abundances of the phyla Proteobacteria, Bacteroidetes, Chloroflexi, and Firmicutes increased in the black-odor water. In addition, the relative abundance of Propionivibrio, a known NH3-N degrading genus, increased. This study will facilitate the use of microbiological methods to repair black-odor water. [ABSTRACT FROM AUTHOR]

The Chinese giant salamander (Andrias davidianus) as food and medicinal product has been an important aquaculture object in China. Study of gene function in the Chinese giant salamander requires accurate normalization though the use of appropriate reference genes. In this study, the expression levels of three candidate reference genes including β‐actin, GAPDH and cytb of different tissues, different developmental stages and different challenges in Chinese giant salamander were evaluated by qPCR. The stabilities of these three reference genes were analysed by geNorm, NormFinder and BestKeeper software. The results showed that the expression of GAPDH was more stable than that of β‐actin and cytb in four tissues and at two developmental stages of Chinese giant salamander. Compared with GAPDH and cytb, β‐actin was the most stable in spleen of Chinese giant salamander treated with LPS or GSIV. Therefore, the result showed that GAPDH was the suitable reference gene in different tissues and at different developmental stages of Chinese giant salamander. The β‐actin could be used as a reference gene in spleen of Chinese giant salamander challenged with LPS and GSIV. This study provides convincing information for the GAPDH and β‐actin as suitable reference gene in Chinese giant salamander of different tissues, different developmental stages and different challenges respectively. [ABSTRACT FROM AUTHOR]

In this study, a yeast strain with an outstanding NH 3 -N degradation ability was isolated from the sediment of a black-odor water channel in Guangdong Province, China. Based on phenotypic and phylogenetic analysis, this strain was identified as Pichia kudriavzevii GW1. The optimum conditions for NH 3 -N degradation by the GW1 strain were as follows: 0.3% inoculum concentration, 1.5 L/min aeration, pH 7, and a temperature of 35°C. Under optimized conditions, the GW1 strain degraded 95.5% of the NH 3 -N. The strain was then added to simulated black-odor water under optimal degradation conditions to investigate changes to the bacterial community over time. 16S rRNA sequencing of samples collected on days 0, 7, 14, and 21 showed that, in the presence of the GW1 strain, the relative abundances of the phyla Proteobacteria, Bacteroidetes, Chloroflexi, and Firmicutes increased in the black-odor water. In addition, the relative abundance of Propionivibrio , a known NH 3 -N degrading genus, increased. This study will facilitate the use of microbiological methods to repair black-odor water., Competing Interests: The authors have no conflicts of interest to declare., (Copyright © 2020 Haiwei Xie et al.)