Pulsatilla decoction alleviates DSS-induced UC by activating FXR-ASBT pathways to ameliorate disordered bile acids homeostasis.

Ethnopharmacological relevance: Pulsatilla decoction (PD) is a classical prescription for the treatment of ulcerative colitis. Previous studies have demonstrated that the therapeutic efficacy of PD is closely associated with the activation of Farnesoid X receptor (FXR). The activity of FXR is regulated by apical sodium-dependent bile acid transporter (ASBT), and the FXR-ASBT cascade reaction, centered around bile acid receptor FXR, plays a pivotal role in maintaining bile acid metabolic homeostasis to prevent the occurrence and progression of ulcerative colitis (UC). Aim of the study: To elucidate the underlying mechanism by which PD exerts its proteactive effects against Dextran Sulfate Sodium Salt (DSS)-induced ulcerative colitis, focusing on the modulation of FXR and ASBT. Materials and methods: To establish a model of acute ulcerative colitis, BALB/C mice were administered 3.5% DSS in their drinking water for consecutive 7 days. The disease activity index (DAI) was employed to evaluate the clinical symptoms exhibited by each group of mice. Goblet cell expression in colon tissue was assessed using glycogen schiff periodic acid-Schiff (PAS) and alcian blue staining techniques. Inflammatory cytokine expression in serum and colonic tissues was examined through enzyme-linked immunosorbent assay (ELISA). A PCR Array chip was utilized to screen 88 differential genes associated with the FXR-ASBT pathway in UC treatment with PD. Western blotting (WB) analysis was performed to detect protein expression levels of differentially expressed genes in mouse colon tissue. Results: The PD treatment effectively reduced the Disease Activity Index (DAI) score and mitigated colon histopathological damage, while also restoring weight and colon length. Furthermore, it significantly alleviated the severity of ulcerative colitis (UC), regulated inflammation, modulated goblet cell numbers, and restored bile acid balance. Additionally, a PCR Array analysis identified 21 differentially expressed genes involved in the FXR-ASBT pathway. Western blot results demonstrated significant restoration of FXR, GPBAR1, CYP7A1, and FGF15 protein expression levels following PD treatment; moreover, there was an observed tendency towards increased expression levels of ABCB11 and RXRα. Conclusion: The therapeutic efficacy of PD in UC mice is notable, potentially attributed to its modulation of bile acid homeostasis, enhancement of gut barrier function, and attenuation of intestinal inflammation.

Antibiotics in the rice-crayfish rotation pattern: Occurrence, prioritization, and resistance risk.

Antibiotics are extensively utilized in aquaculture to mitigate diseases and augment the productivity of aquatic commodities. However, to date, there have been no reports on the presence and associated risks of antibiotics in the emergent rice-crayfish rotation (RCR) system. This study investigated the occurrence, temporal dynamics, prioritization, sources, and potential for resistance development of 15 antibiotics within the RCR ecosystem. The findings revealed that during the crayfish breeding and rice planting periods, florfenicol (FFC) predominated in the RCR's surface water, with peak and average concentrations of 1219.70 ng/L and 57.43 ng/L, and 1280.70 ng/L and 52.60 ng/L, respectively. Meanwhile, enrofloxacin (ENX) was the primary antibiotic detected in RCR soil and its maximum and average concentrations were 624.73 ng/L and 69.02 ng/L in the crayfish breeding period, and 871.27 ng/L and 45.89 ng/L in the rice planting period. Throughout the adjustment period, antibiotic concentrations remained relatively stable in both phases. Notably, antibiotic levels in surface water and soil escalated during the crayfish breeding period and subsided during the rice planting period, with these fluctuations predominantly influenced by FFC and ENX. Source analysis indicated that the antibiotics in RCR predominantly originated from aquaculture activities, supplemented by water exchange processes. Utilizing the entropy utility function and a resistance development model, FFC, clarithromycin (CLR), and roxithromycin (ROX) in surface water, along with ENX, CLR, and ROX in soil, were identified as priority antibiotics. FFC, ENX, and ROX exhibited a medium risk for resistance development. Consequently, this study underscores the necessity to intensify antibiotic usage control during the crayfish breeding period in the RCR system to mitigate environmental risks.

Fate of high-risk antibiotic resistance genes in large-scale aquaculture sediments: Geographical differentiation and corresponding drivers.

Antibiotic resistance genes (ARGs), emerging environmental contaminants, have become challenges of public health security. However, the distribution and drivers of ARGs, especially high-risk ARGs, in large-scale aquaculture sediments remain unknown. Here, we collected sediment samples from 40 crayfish ponds in seven main crayfish culture provinces in China and then investigated the distribution and risk of ARGs based on high-throughput sequencing and quantitative PCR techniques. Our results suggested that aquaculture sediment was potential reservoir of ARGs and the abundance of aadA-02 was the highest. High-risk ARG (floR) was also prevalent in the sediment and was the most abundant in Jiangsu Province, where opportunistic pathogens were also enriched. The abundance of floR was positively correlated with different environmental factors, such as total phosphorus in water and total carbon in sediment. In addition, Mycobacterium sp., opportunistic pathogenic bacteria, might be potential host for floR. Furthermore, the potential propagation pathway of ARGs was from sediment to crayfish gut, and Bacteroidetes and Proteobacteria might be the main bacterial groups responsible for the proliferation of ARGs. Generally, our results illustrate that pond sediment may be an ARG reservoir of aquatic animals. Meanwhile, our study helps develop valuable strategies for accessing risks and managing ARGs.

Occurrence, distribution, and ecological risks of antibiotics in Honghu Lake and surrounding aquaculture ponds, China.

Antibiotics are largely applied in aquaculture to increase production and control diseases, while how the antibiotics used in pond farming influence the distribution of antibiotics in receiving water seasonally is still not well understood. In this study, the variations of 15 frequently used antibiotics in Honghu Lake and surrounding ponds were investigated seasonally to figure out the impact of pond farming on antibiotics distributions in Honghu Lake. Results showed that the antibiotic concentrations in fish ponds ranged from 11.76 to 389.8 ng/L, while in crab and crayfish ponds were lower than 30.49 ng/L. The predominant antibiotic in fish ponds was florfenicol, followed by sulfonamides and quinolones, with generally low concentrations. Sulfonamides and florfenicol were the main antibiotics in Honghu Lake, affected by the surrounding aquaculture water partially. The antibiotics residue in aquaculture ponds showed obvious seasonal characteristics, with the lowest in spring. From summer, the concentrations of antibiotics in aquaculture ponds gradually increased and reached a peak in autumn, and the seasonal variation of antibiotics in the receiving lake was also related to the antibiotics in the aquaculture ponds. Risk assessment analysis showed that antibiotics such as enrofloxacin and florfenicol in fish ponds posed a medium and low risk to algae, and Honghu Lake acted as a natural reservoir of antibiotics and poses increased risks to algae. In general, our study demonstrated that aquaculture represented by pond farming brought significant risks of antibiotic pollution to natural water bodies. Therefore, reasonable control of the fish antibiotics usage in autumn and winter, as well as the rational use of antibiotics in aquaculture and the use of antibiotics before pond cleaning, is required to reduce the migration of antibiotics from aquaculture surface water to the receiving lake.

Improved protein glycosylation enabled heterologous biosynthesis of monoterpenoid indole alkaloids and their unnatural derivatives in yeast.

With over 3000 reported structures, monoterpenoid indole alkaloids (MIAs) constitute one of the largest alkaloid groups in nature, including the clinically important anticancer drug vinblastine and its semi-synthetic derivatives from Catharanthus roseus (Madagascar's periwinkle). With the elucidation of the complete 28-step biosynthesis for anhydrovinblastine, it is possible to investigate the heterologous production of vinblastine and other medicinal MIAs. In this study, we successfully expressed the flavoenzyme O-acetylstemmadenine oxidase in Saccharomyces cerevisiae (baker's yeast) by signal peptide modification, which is a vinblastine biosynthetic gene that has not been functionally expressed in this system. We also reported the simultaneous integration of ∼18 kb MIA biosynthetic gene cassettes as single copies into four genomic loci of baker's yeast by CRISPR-Cas9, which enabled the biosynthesis of vinblastine precursors catharanthine and tabersonine from the feedstocks secologanin and tryptamine. We further demonstrated the biosynthesis of fluorinated and hydroxylated catharanthine and tabersonine derivatives using our yeasts, which showed that the MIA biosynthesis accommodates unnatural substrates, and the system can be further explored to produce other complex MIAs.

Characteristics of (micro)plastic transport in the upper reaches of the Yangtze River.

Many studies focus on the transport of plastic from rivers to oceans while little attention was paid to the plastic transport in the upper reaches of rivers. Transport process of plastic from upstream to downstream in the whole river basin scale is still poorly understood. In this work, five sections in the upper reaches of the Yangtze River were investigated to characterize the features of plastic transport. Plastic abundance and flux were 293 to 156,667 n/m3 and 1.2 to 34,711 g/s, respectively. Plastic flux peaked at or right after the first flood peak in most sections, but plastic abundance was the highest in the normal or low water period. The first flood peak caused a temporary rise of plastic flux that last a short duration. Transport of plastic was not limited to water surface, and the Three Gorges Dam showed a peak elimination effect on plastic transport. Annual discharge of plastic was 1392 to 9532 tons and 6.2 × 1014 to 175 × 1014 particles at different sections. An increasing trend was observed for both plastic mass and quantity going downstream. Results showed that river plastic flux is highly variable and influenced by the dam, which should be considered in future to develop better monitoring strategies and to further improve the model.

Distribution and influencing factors of antibiotic resistance genes of crayfish (Procambarus clarkii) intestine in main crayfish breeding provinces in China.

The propagation of antibiotic resistance genes (ARGs) has become a global public health concern. However, the distribution and influencing factors of ARGs, especially high-risk ARGs, in the gut of aquaculture animals remain unclear. Here, we employed 16S rRNA gene sequencing and high-throughput quantitative PCR techniques to determine crayfish gut microbiota and ARGs collected from 40 culture ponds in major crayfish farming provinces of China. We detected 74 ARGs in crayfish gut. Among them, the beta-lactamase and tetracycline resistance genes were dominant. The total ARG abundance was the highest in Hubei Province. High-risk ARGs were also found in crayfish gut, and ermB had the highest abundance and distributed in Anhui, Hubei, Henan and Jiangxi Province. In addition, opportunistic pathogens (Streptococcus, Aeromonas and Acinetobacter) might be potential hosts for ARGs, including high-risk ARGs. Finally, habitat, environmental factors (NO3-N, pH and temperature), microbial alpha diversity and mobile genetic elements (MGEs) showed significant influence on ARGs profiles. Generally, our results illustrate that ARGs are prevalent in crayfish gut and may pose potential risk to human health, which will help develop targeted strategies for the risk management and assessment of ARGs in the aquaculture.

Microbial Diversity Analyses of Fertilized Thitarodes Eggs and Soil Provide New Clues About the Occurrence of Chinese Cordyceps.

Chinese cordyceps is a well-known fungus-larva complex with medicinal and economic importance. At present the occurrence of Chinese cordyceps has not been fully illuminated. In this study, the microbial diversities of fertilized Thitarodes eggs from sites A (high occurrence rates of Chinese cordyceps), B (low occurrence rates), and C (no Chinese cordyceps) were analyzed using 16S rRNA and ITS gene-sequencing technique. The previous sequencing data of soil from the same sites were conjointly analyzed. The results showed that bacterial communities among the eggs were significantly different. The bacterial diversity and evenness were much higher on site A. Wolbachia was overwhelmingly predominant in the eggs of sites B and C, while Spiroplasma showed preference on site A. The fungal between-group differences in the eggs were not as significant as that of bacteria. Purpureocillium in Cordyceps-related families showed preference on site A. Wolbachia, Spiroplasma, and Purpureocillium were inferred to be closely related to Chinese cordyceps occurrence. Intra-kingdom and inter-kingdom network analyses suggest that closer correlations of microbial communities (especially closer fungal positive correlations) in fertilized eggs might promote Chinese cordyceps occurrence. Besides, metabolic pathway analysis showed that in fertilized eggs or soil the number of bacterial metabolic pathways with significant differences in every comparison between two sites was greater than that of fungi. Collectively, this study provides novel information about the occurrence of Chinese cordyceps, contributing to the large-scale artificial cultivation of Chinese cordyceps.

Manipulation of fish community structure effectively restores submerged aquatic vegetation in a shallow subtropical lake.

Fish community manipulation and regulation has been largely overlooked as a mitigation strategy for restoring submerged aquatic vegetation (SAV) in shallow lakes of the middle and lower Yangtze River Basin (MLYRB). An in-situ fish exclusion experiment and a large-scale lake manipulation were conducted to test the hypothesis that the reasonable removal of benthivorous and herbivorous fish would facilitate the restoration and reconstruction of SAV in shallow lakes within the MLYRB. The in-situ exclusion experiment was conducted from April to October in 2017. Electrofishing was used to remove benthivorous and herbivorous fish from the exclosures. SAV were then artificially planted in the same pattern and density in both exclosures and adjacent open sites, and responses were measured for seven consecutive months. The mean percent coverage and biomass of SAV in the exclosures increased quickly and remained significantly higher than those in open sites over the duration of the experiment. Water quality also improved as turbidity, chlorophyll-a, total phosphorus and total nitrogen in the exclosures remained significantly lower than those in the open sites. After the in-situ experiment, a larger scale manipulation of fish in the entire submerged macrophyte zone (SMZ) was implemented from 2017 to 2020. After removing more than 2/3 of the benthivorous and herbivorous fish biomass by October 2020 in the SMZ, both the species richness and spatial coverage of SAV increased from 2 to 9 and from 1.7% to 32.2%, respectively. Our results provided clear evidence that fish are strong regulators of SAV productivity and that their reasonable removal facilitates ecological recovery. Therefore, we propose that fish community manipulation as implemented in this study be given more attention in addition to the reduction of external nutrient loading when designing projects to restore SAV in shallow lakes of the MLYRB.