Jingjing Song

Elucidating microbial community shifts under polycyclic aromatic hydrocarbon (PAH) stress and screening indigenous PAH‐tolerant microbial resources are valuable for exploring potential bioremediation strategies for PAH‐contaminated mangrove ecosystems. In this study, surface sediments were collected from mangrove wetlands of the Maowei Sea, Guangxi, China. Three rounds of successive 7‐day enrichment cultures were performed with gradually elevated PAH concentrations using phenanthrene, anthracene, and pyrene as target carbon substrates, followed by isolation and taxonomic identification of PAH‐adapted bacteria. The results demonstrated that microbial community diversity decreased with increasing enrichment rounds and varied significantly among different PAH substrate treatments. ANOSIM confirmed significant differences in community structure across enrichment cycles and PAH treatments ( p < 0.01), consistent with the ordination patterns revealed by Non‐metric Multidimensional Scaling (NMDS). The PAH‐adapted microbial communities were predominantly dominated by Pseudomonadota (33.2%–99.9%), Bacillota (0%–48.3%), and Actinomycetota (0.1%–33.7%). In total, 17 indigenous PAH‐tolerant bacterial strains belonging to eight genera within the phylum Pseudomonadota were isolated, with representative strains affiliated with Labrys , Sphingomonas , and Acinetobacter . Within the tested physiological gradient ranges, Labrys sp. F3‐1 and Acinetobacter sp. B1‐5 exhibited optimal growth at pH 5.0, 40°C, and 15‰ salinity, while Sphingomonas sp. N2‐15 showed the best growth performance at pH 5.0, 25°C, and 4‰ salinity. Growth assays under PAH pressure further verified that these three isolates could survive and proliferate in PAH‐amended selective media under the tested laboratory conditions. This study provides indigenous PAH‐tolerant bacterial resources and fundamental community‐level insights for future investigations on microbial‐based remediation of PAH‐polluted mangrove sediments. Notably, the high PAH concentrations applied during laboratory enrichment (100–500 mg/L) were substantially higher than in situ environmental levels; the observed microbial responses and strain physiological traits reflect adaptive characteristics under extreme laboratory selective pressure and should be cautiously extrapolated to natural mangrove ecosystems.

This study analyzed flower bud differentiation and fruiting stages to investigate how the structure of the plant endophytic microbial community in the roots of tomatoes changes with plant senescence. Based on high-throughput sequencing technology, the diversity and relative abundance of endophytic microorganisms (bacteria and fungi) in tomato stems at different growth stages were analyzed. At the same time, based on LEfSe analysis, the differences in endophytic microorganisms in tomato stems at different growth stages were studied. Based on PICRUSt2 function prediction and FUNGuild, we predicted the functions of endophytic bacterial and fungal communities in tomato stems at different growth stages to explore potential microbial functional traits. The results demonstrated that not only different unique bacterial genera but also unique fungal genera could be found colonizing tomato roots at different growth stages. In tomato seedlings, flower bud differentiation, and fruiting stages, the functions of colonizing endophytes in tomato roots could primarily contribute to the promotion of plant growth, stress resistance, and improvement in nutrient cycling, respectively. These results also suggest that different functional endophytes colonize tomato roots at different growth stages.

Chlorella vulgaris is one of the most commonly used microalgae in aquaculture feeds. It contains high concentrations of various kinds of nutritional elements that are involved in the physiological regulation of aquaculture animals. However, few studies have been conducted to illustrate their influence on the gut microbiota in fish. In this work, the gut microbiota of Nile tilapia (Oreochromis niloticus) (average weight is 6.64 g) was analyzed by high-throughput sequencing of the 16S rRNA gene after feeding with 0.5% and 2% C. vulgaris additives in diets for 15 and 30 days (average water temperature was 26 °C). We found that the impact of C. vulgaris on the gut microbiota of Nile tilapia was feeding-time dependent. Only by feeding for 30 days (not 15 days) did the addition of 2% C. vulgaris to diets significantly elevate the alpha diversity (Chao1, Faith pd, Shannon, Simpson, and the number of observed species) of the gut microbiota. Similarly, C. vulgaris exerted a significant effect on the beta diversity (Bray–Curtis similarity) of the gut microbiota after feeding for 30 days (not 15 days). During the 15-day feeding trial, LEfSe analysis showed that Paracoccus, Thiobacillus, Dechloromonas, and Desulfococcus were enriched under 2% C. vulgaris treatment. During the 30-day feeding trial, Afipia, Ochrobactrum, Polymorphum, Albidovulum, Pseudacidovorax, and Thiolamprovum were more abundant in 2% C. vulgaris-treated fish. C. vulgaris promoted the interaction of gut microbiota in juvenile Nile tilapia by increasing the abundance of Reyranella. Moreover, during the feeding time of 15 days, the gut microbes interacted more closely than those during the feeding time of 30 days. This work will be valuable for understanding how C. vulgaris in diets impacts the gut microbiota in fish.

The aim of the study was to investigate the inhibitory effect of hydroxysaff yellow A (HSYA) on diabetic retinopathy (DR). For this, a total of 27 rats were randomly divided into normal control, model, and HSYA groups. The body weight, blood glucose, and blood–retinal barrier damage of the rats were observed and compared. The pathological change of retinal tissue were measured using H&E staining. The apoptosis of retinal tissue ganglion cells was detected by TUNEL. The interleukin (IL)-1β and tumor necrosis fator (TNF)-α levels were detected using enzyme-linked immunosorbent assay. The level of malondialdehyde (MDA) was detected using thiobarbituric acid method. Superoxide dismutase levels were detected using xanthine oxidase method; Nrf2 and total HO-1 protein expressions were detected using western blot assay; Bcl-2 and P53 protein expression was measured using immunohistochemical staining. The body weight and retinal damage of the HYSA group were significantly improved (p< 0.01, respectively). The apoptosis index of the HYSA group was lower than the model group (p< 0.001). The IL-1β, TNF-α, and MDA levels of the HYSA group were significantly improved in comparison with those of the model group (p< 0.01, respectively). The Nrf-2, HO-1, Bcl-2, and P53 protein expression of HYSA group was significantly improved (p< 0.001, respectively). In conclusion, HYSA can effectively alleviate the apoptosis of retinal ganglion cells in type 2 diabetic rats and improve the progression of DR.