Deltamethrin increased susceptibility to Aeromonas hydrophila in crucian carp through compromising gill barrier.

Pyrethroids serve as a significant method for managing and preventing parasitic diseases in fish. Among these, deltamethrin (DEL) is used extensively in aquatic environments. Our previous work has been confirmed that DEL exposure can induce oxidative stress and immunosuppression on the gill mucosal barrier of crucian carp (Carassius auratus). However, it is not clear whether DEL affects the susceptibility of farmed fish to bacterial infection. In this study, fish was pre-exposed to different DEL concentration (0, 0.3 and 0.6 µg L-1) and then challenged by immersion with Aeromonas hydrophila (1.0 × 10^8 CFU mL-1). After immersion challenge, fish pre-exposed to DEL developed prominent lipopolysaccharides level in gill and serum and had a significantly lower survival rate compared to the control group. In DEL pre-exposure fish after immersion, the gill apoptosis levels were significantly higher and disrupted the tight junction barrier by downregulating the zo1 and claudin12. Furthermore, fish pre-exposed to DEL exhibited increased activities of superoxide dismutase (SOD), total antioxidant capacity (T-AOC), and malonaldehyde (MDA) levels in the early stage after immersion but experiencing decreased activities of glutathione peroxidase (GPx) and lysozyme (LZM) in the later stage after immersion. And this process was regulated by the NRF2 pathway. Additionally, fish pre-exposed to DEL after immersion had significantly lower mRNA levels of immune-related genes tlr4, myd88, tnfα, and il-1ß. Overall, these findings indicate that DEL damaged the gill barrier, weakened the immune response, raised LPS levels, and heightened vulnerability to A. hydrophila infection in crucian carp, resulting in mortality. Thus, this work will help social groups and aquaculture workers to understand the potential risk of DEL exposure for bacterial secondary infection in cultured fish.

Plant-derived virulence arresting drugs as novel antimicrobial agents: Discovery, perspective, and challenges in clinical use.

Antimicrobial resistance (AMR) emerges as a severe crisis to public health and requires global action. The occurrence of bacterial pathogens with multi-drug resistance appeals to exploring alternative therapeutic strategies. Antivirulence treatment has been a positive substitute in seeking to circumvent AMR, which aims to target virulence factors directly to combat bacterial infections. Accumulated evidence suggests that plant-derived natural products, which have been utilized to treat infectious diseases for centuries, can be abundant sources for screening potential virulence-arresting drugs (VADs) to develop advanced therapeutics for infectious diseases. This review sums up some virulence factors and their actions in various species of bacteria, as well as recent advances pertaining to plant-derived natural products as VAD candidates. Furthermore, we also discuss natural VAD-related clinical trials and patents, the perspective of VAD-based advanced therapeutics for infectious diseases and critical challenges hampering clinical use of VADs, and genomics-guided identification for VAD therapeutic. These newly discovered natural VADs will be encouraging and optimistic candidates that may sustainably combat AMR.

Zeaxanthin prevents ferroptosis by promoting mitochondrial function and inhibiting the p53 pathway in free fatty acid-induced HepG2 cells.

Non-alcoholic fatty liver disease (NAFLD) is a common liver disorder worldwide and a risk factor for obesity and diabetes. Emerging evidence has shown that ferroptosis is involved in the progression of NAFLD. Zeaxanthin (ZEA) is a carotenoid found in human serum. It has been reported that ZEA can ameliorate obesity, prevent age-related macular degeneration, and protect against non-alcoholic steatohepatitis. However, no study has focused on the protective effects of ZEA against NAFLD. In this study, free fatty acid (FFA) induced HepG2 cells were used as a cell model for NAFLD. Our results suggest that ZEA exerts antioxidative and anti-inflammatory effects in FFA-induced HepG2 cells. Moreover, ZEA acted as a ferroptosis inhibitor, significantly reducing reactive oxygen species (ROS) generation and iron overload and improving mitochondrial dysfunction in FFA-induced HepG2 cells. In addition, ZEA downregulated the expression of p53 and modulated downstream targets, such as GPX4, SLC7A11, SAT1, and ALOX15, which contributed to the reduction in cellular lipid peroxidation. Our findings suggest that ZEA has the potential for NAFLD intervention.

Phylogeographic patterns and conservation implications of the endangered Chinese giant salamander.

Understanding genetic diversity patterns of endangered species is an important premise for biodiversity conservation. The critically endangered salamander Andrias davidianus, endemic to central and southern mainland in China, has suffered from sharp range and population size declines over the past three decades. However, the levels and patterns of genetic diversity of A. davidianus populations in wild remain poorly understood. Herein, we explore the levels and phylogeographic patterns of genetic diversity of wild-caught A. davidianus using larvae and adult collection with the aid of sequence variation in (a) the mitochondrial DNA (mtDNA) fragments (n = 320 individuals; 33 localities), (b) 19 whole mtDNA genomes, and (c) nuclear recombinase activating gene 2 (RAG2; n = 88 individuals; 19 localities). Phylogenetic analyses based on mtDNA datasets uncovered seven divergent mitochondrial clades (A-G), which likely originated in association with the uplifting of mountains during the Late Miocene, specific habitat requirements, barriers including mountains and drainages and lower dispersal ability. The distributions of clades were geographic partitioned and confined in neighboring regions. Furthermore, we discovered some mountains, rivers, and provinces harbored more than one clades. RAG2 analyses revealed no obvious geographic patterns among the five alleles detected. Our study depicts a relatively intact distribution map of A. davidianus clades in natural species range and provides important knowledge that can be used to improve monitoring programs and develop a conservation strategy for this critically endangered organism.

A New Species of Sulcospira (Gastropoda: Pachychilidae) from Hunan, China.

A new species of pachychilid freshwater gastropod, Sulcospira hunanensis sp. nov., is described from Hunan Province, China, based on morphological and molecular evidence. The new species is distinguished from its congeners by a combination of characters, including elongated shell with eight to nine whorls, spiral whorls with ribs, and stomach with outer and inner crescentic pads not connected to each other. Sulcospira hunanensis sp. nov. is the first confirmed report of this genus from Hunan Province, China. It is anticipated that further species will be found in this region, which currently remain unknown. Furthermore, based on morphological and molecular evidence, this study is the first record of Sulcospira tonkiniana in Guangxi Zhuang Autonomous Region, China, with Sulcospira krempfi supported as a synonym of Sulcospira tonkiniana.

Complete mitochodrial genome of Bangana decora (Cypriniformes, Cyprinidae).

The complete mitochondrial genome of Bangana decora was determined in this study. The gene composition, arrangement and transcriptional orientation in B. decora mitogenome were identical to most vertebrates. The complete mitogenome of B. decora was 16,607 bp in size with 13 protein-coding genes, 22 tRNA genes and a control region. Two start codon patterns and three stop codon patterns were found in protein-coding genes. Only the tRNA-Ser2 could not fold into a typical clover-leaf secondary structure due to the absence of the dihydrouridine arm. Sequence alignment results suggest that the complete mitogenome of B. decora is an efficient tool to study molecular phylogenetics, biogeography and adaptive evolution of this lineage.

Complete mitochodrial genome of Vanmanenia pingchowensis (Cypriniformes, Cyprinidae).

The complete mitochondrial genome of Vanmanenia pingchowensis was determined in this study. The gene composition, arrangement and transcriptional orientation in V. pingchowensis mitogenome were identical to most vertebrates. The complete mitogenome of V. pingchowensis was 15,560 bp in size with 13 protein coding genes, 22 tRNA genes, and a control region. Two start codon patterns and three stop codon patterns were found in protein-coding genes. Only the tRNA-Ser2 could not fold into a typical clover-leaf secondary structure for lacking the dihydrouridine arm. Sequences alignment results suggest that the complete mitogenome of V. pingchowensis is an efficient tool to study molecular phylogenetics, biogeography and adaptive evolution of this lineage.

Complete mitochodrial genome of Elopichthys bambusa (Cypriniformes, Cyprinidae).

The complete mitochondrial genome of Elopichthys bambusa was determined in this study. The gene composition, arrangement and transcriptional orientation in E. bambusa mitogenome were identical to most vertebrates. Two start codon patterns (ATG and GTG) and three stop codon patterns (TAG, TAA and T) were found in protein-coding genes. Only the tRNA-Ser2 could not fold into a typical clover-leaf secondary structure for lacking the dihydrouridine arm. Sequences alignment results suggest that the complete mitogenome of E. bambusa is an efficient tool to check species identification by comparing different gene sequences.