Impact of environmental factors on diversity of fungi in sediments from the Shenzhen River Estuary.

In this study, to explore the relationship between environmental factors and fungal diversity in the Shenzhen River ecosystem, multiple methods including chemical analysis, culture isolation, qPCR analysis of fungal ITS region and ITS-based Illumina next-generation-sequencing were integrated. A total of 115 isolates were finally isolated and could be classified into 23 genera. Top three abundant genera isolated were Meyerozyma (18 strains), Aspergillus (17 strains) and Penicillium (14 strains). Based on the Illumina sequencing approach, 829 OTUs were affiliated to seven phyla, 17 known classes, and 162 genera, indicating the Shenzhen estuary sediments are rich in fungal diversity. The major fungal genera were Meyerozyma, Trichoderma and Talaromyces. Environmental factors showed a gradient change in Shenzhen estuary, and fungal abundance was only significantly correlated with NH4+. Shannon index was significantly correlated with pH and IC (P < 0.05). Principal coordinate analysis based on OTU level grouped into three clusters among sampling sites along with the IC and pH gradient. Functional guilds analysis suggests most of the fungi in this studying area were almost all saprotrophs, suggesting a large number of saprophytic fungi may play a significant role in the organic matter decomposition and nutrient cycling process. In summary, this study will deepen our understanding of fungi community in Shenzhen River ecosystem and their distribution and potential function shaped by environmental factors.

Halomonas dongshanensis sp. nov., isolated from the seawater of Dongshan Island.

A taxonomic study was carried out on strain yzlin-01T, isolated from Dongshan Island seawater. The bacterium was Gram-stain-negative, catalase-positive, oxidase-negative, rod-shaped, and motile by polar flagella. Growth was observed at temperatures of 10-40 °C, at salinities of 0.5-18 %, and at pH of 6-10. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain yzlin-01T belonged to the genus Halomonas, with the highest sequence similarity to Halomonas malpeensis YU-PRIM-29T (96.7 %), followed by Halomonas johnsoniae T68687T (96.4 %) and Halomonas gomseomensis M12T (96.4 %), and other species of the genus Halomonas (93.4-96.3 %). The ANI and digital DNA-DNA hybridization estimate values between strain yzlin-01T and the closest type strain Halomonas malpeensis YU-PRIM-29T were 77.44 and 21.6 %, respectively. The principal fatty acids were summed feature 8 (consisting of C18 : 1 ω7c and/or C18 : 1 ω6c; 55.7 %), C16 : 0 (20.6 %), C12 : 0 3-OH (6.8 %), summed feature 3 (consisting of C16 : 1 ω7c and/or C16 : 1 ω6c; 5.1 %). The G+C content of the chromosomal DNA was 60.0 mol %. The respiratory quinone was identified as Q-9 (100 %). Phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, aminophospholipid, and three unidentified phospholipids were present. Combined genotypic and phenotypic data suggest that strain yzlin-01T represents a novel species within the genus Halomonas, for which the name Halomonas dongshanensis sp. nov. is proposed, with the type strain yzlin-01T (=GDMCC 1.3202T=KCTC 92467T).

Structure Revisions of Phenolic Bisabolane Sesquiterpenes and a Ferroptosis Inhibitor from the Marine-Derived Fungus Aspergillus versicolor YPH93.

Seven new phenolic bisabolane sesquiterpenoids (1-7), along with 10 biogenetically related analogues (8-17), were obtained from the deep-sea-derived fungus Aspergillus versicolor YPH93. The structures were elucidated based on extensive analyses of the spectroscopic data. Compounds 1-3 are the first examples of phenolic bisabolanes that contain two hydroxy groups attached to the pyran ring. The structures of sydowic acid derivatives (1-6 and 8-10) were carefully studied, leading to the structure revisions of six known analogues, including a revision of the absolute configuration for sydowic acid (10). All metabolites were evaluated for their effects on ferroptosis. Compound 7 exerted inhibition on erastin/RSL3-induced ferroptosis with EC50 values ranging from 2 to 4 µM, while it exhibited no effects on TNFα-induced necroptosis or H2O2-induced cell necrosis.