Identification of TonB-dependent siderophore receptor inhibitors against Flavobacterium columnare using a structure-based high-throughput virtual screening method.

TonB-dependent siderophore receptors play a critical transport role for Flavobacterium columnare virulence formation and growth, and have become valuable targets for the development of novel antimicrobial agents. Traditional Chinese medicine has demonstrated notable efficacy in the treatment of fish diseases and includes potential antibacterial agents. Herein, we performed molecular docking-based virtual screening to discover novel TonB-dependent siderophore receptor inhibitors from traditional Chinese medicine and provide information for developing novel antibacterial agents. Firstly, we efficiently obtained 11 potential inhibitors with desirable drug-like characteristics from thousands of compounds in the TCM library based on virtual screening and property prediction. The antibacterial activity of Enoxolone, along with its interaction characteristics, were determined via an MIC assay and molecular dynamic simulation. Transcriptional profiling, along with validation experiments, subsequently revealed that an insufficient uptake of iron ions by bacteria upon binding to the TonB-dependent siderophore receptors is the antibacterial mechanism of Enoxolone. Finally, Enoxolone's acceptable toxicity was illustrated through immersion experiments. In summary, we have used virtual screening techniques for the first time in the development of antimicrobial agents in aquaculture. Through this process, we have identified Enoxolone as a promising compound targeting the TonB-dependent siderophore receptor of F. columnare. In addition, our findings will provide new ideas for the advancement of innovative antimicrobial medications in aquaculture.

A novel ESIPT fluorescent probe for early detection and assessment of ferroptosis-mediated acute kidney injury via peroxynitrite fluctuation.

BACKGROUND: Acute kidney injury (AKI) poses a severe risk to public health, mostly manifested by damage and death of renal tubular epithelial cells. However, routine blood examination, a conventional approach for clinical detection of AKI, is not available for identifying early-stage AKI. Plenty of reported methods were lack of early biomarkers and real time evaluation tools, which resulted in a vital challenge for early diagnosis of AKI. Therefore, developing novel probes for early detection and assessment of AKI is exceedingly crucial. RESULTS: Based on ESIPT mechanism, a new fluorescent probe (MEO-NO) with 2-(2'-hydroxyphenyl) benzothiazole (HBT) derivatives as fluorophore has been synthesized for dynamic imaging peroxynitrite (ONOO-) levels in ferroptosis-mediated AKI. Upon the addition of ONOO-, MEO-NO exhibited obvious fluorescence changes, a significant Stokes shift (130 nm) and rapid response (approximately 45 s), and featured exceptional sensitivity (LOD = 7.28 nM) as well as high selectivity from the competitive species at physiological pH. In addition, MEO-NO was conducive to the biological depth imaging ONOO- in cells, zebrafish, and mice. Importantly, MEO-NO could monitor ONOO- levels during sorafenib-induced ferroptosis and CP-induced AKI. With the assistance of MEO-NO, we successfully visualized and tracked ONOO- variations for early detection and assessment of ferroptosis-mediated AKI in cells, zebrafish and mice models. SIGNIFICANCE AND NOVELTY: Benefiting from the superior performance of MEO-NO, experimental results further demonstrated that the levels of ONOO- was overexpressed during ferroptosis-mediated AKI in cells, zebrafish, and mice models. The developed novel probe MEO-NO provided a strong visualization tool for imagining ONOO-, which might be a potential method for the prevention, diagnosis, and treatment of ferroptosis-mediated AKI.

Identification of potential anti-tumor targets and mechanisms of HuaChanSu injection using network pharmacology and cytological experiments in Breast cancer.

HuaChanSu (HCS) or Cinobufacini injection is an aqueous extract of the dried skin of Bufo bufo gargarigans, and has anti-tumor effects. The aim of this study was to evaluate the possible therapeutic effect of HCS against breast cancer (BRCA) using cytology, network pharmacology, and molecular biology approaches. The half-inhibitory concentration (IC50) of HCS in the BRCA cells was determined by cytotoxicity assay, and were accordingly treated with high and low doses HCS in the TUNEL and scratch assays. The potential targets of HCS in the BRCA cells were identified through functional enrichment analysis and protein-protein interaction (PPI) networks, and verified by molecular docking. The expression levels of key signaling pathways-related proteins in HCS-treated BRCA cells by western blotting. HCS inhibited the proliferation and migration of MCF-7 and MDA-MB-231 cells, and induced apoptosis in a dose-dependent manner. Furthermore, we screened 289 core HCS targets against BRCA, which were primarily enriched in the PI3K-AKT, MAPK chemokines, and other. signaling pathways. In addition, PIK3CA, PIK3CD, and MTOR were confirmed as HCS targets by molecular docking. Consistent with this, we observed a reduction in the expression levels of phosphorylated PI3K, AKT, and MTOR in the HCS-treated BRCA cells. Taken together, our findings suggest that HCS inhibits the growth of BRCA cells by targeting the PI3K-AKT pathway, and warrants further investigation as a therapeutic agent for treating patients with BRCA.

circular RNA circ-231 promotes protein biogenesis of TPI1 and PRDX6 through mediating the interaction of eIF4A3 with STAU1 to facilitate unwinding of secondary structure in 5' UTR, enhancing progression of human esophageal squamous cell carcinoma (ESCC).

Background: The nuclear cap-binding complex (CBC)-dependent translation (CT) is an important initial translation pathway for 5'-cap-dependent translation in normal mammal cells. Eukaryotic translation initiation factor 4A-III (eIF4A3), as an RNA helicase, is recruited to CT complex and enhances CT efficiency through participating in unwinding of secondary structure in the 5' UTR. However, the detailed mechanism for eIF4A3 implicated in unwinding of secondary structure in the 5' UTR in normal mammal cells is still unclear. Specially, we need to investigate whether the kind of mechanism in normal mammal cells extrapolates to cancer cells, e.g. ESCC, and further interrogate whether and how the mechanism triggers malignant phenotype of ESCC, which are important for identifying a potential therapeutic target for patients with ESCC. Methods: Bioinformatics analysis, RNA immunoprecipitation and RNA pulldown assays were performed to detect the interaction of circular RNA circ-231 with eIF4A3. In vitro and in vivo assays were performed to detect biological roles of circ-231 in ESCC. RNA immunoprecipitation, RNA pulldown, mass spectrometry analysis and co-immunoprecipitation assays were used to measure the interaction of circ-231, eIF4A3 and STAU1 in HEK293T and ESCC. In vitro EGFP reporter and 5' UTR of mRNA pulldown assays were performed to probe for the binding of circ-231, eIF4A3 and STAU1 to secondary structure of 5' UTR. Results: RNA immunoprecipitation assays showed that circ-231 interacted with eIF4A3 in HEK293T and ESCC. Further study confirmed that circ-231 orchestrated with eIF4A3 to control protein expression of TPI1 and PRDX6, but not for mRNA transcripts. The in-depth mechanism study uncovered that both circ-231 and eIF4A3 were involved in unwinding of secondary structure in 5' UTR of TPI1 and PRDX6. More importantly, circ-231 promoted the interaction between eIF4A3 and STAU1. Intriguingly, both circ-231 and eIF4A3 were dependent on STAU1 binding to secondary structure in 5' UTR. Biological function assays revealed that circ-231 promoted the migration and proliferation of ESCC via TPI1 and PRDX6. In ESCC, the up-regulated expression of circ-231 was observed and patients with ESCC characterized by higher expression of circ-231 have concurrent lymph node metastasis, compared with control. Conclusions: Our data unravels the detailed mechanism by which STAU1 binds to secondary structure in 5' UTR of mRNAs and recruits eIF4A3 through interacting with circ-231 and thereby eIF4A3 is implicated in unwinding of secondary structure, which is common to HEK293T and ESCC. However, importantly, our data reveals that circ-231 promotes migration and proliferation of ESCC and the up-regulated circ-231 greatly correlates with tumor lymph node metastasis, insinuating that circ-231 could be a therapeutic target and an indicator of risk of lymph node metastasis for patients with ESCC.

Effects of Meloxicam on the Welfare of Holstein Calves from 6 Weeks to 6 Months Old Undergoing Amputation Dehorning.

Amputation dehorning (AD) is a common practice performed on calves, causing harmful effects such as pain, distress, anxiety, and fear. These effects extend to behavioral, physiological, and hematological responses, prompting serious ethical concerns regarding animal welfare, even when performed with local anesthesia. Meloxicam, a non-steroidal anti-inflammatory drug, has been widely used to mitigate the side effects of dehorning and disbudding in calves. However, there is a notable gap in research regarding the effects of meloxicam on calves aged 6 weeks to 6 mo undergoing AD procedures. This study was designed to assess the effectiveness of co-administering meloxicam with lidocaine, a cornual nerve anesthetic, in alleviating the adverse effects caused by the AD procedure in calves within this age range, compared with the use of lidocaine alone. Thirty Holstein calves were enrolled and randomly divided into 2 groups. The first group (Placebo) received a subcutaneous injection of 5 mL of lidocaine in the horn area and a subcutaneous injection of 0.9% saline at a dose of 0.025 mL/kg in the neck, administered 10 min before the AD procedure. The second group (MX) received a combination of lidocaine and meloxicam: a subcutaneous injection of 5 mL of lidocaine in the horn area and a subcutaneous injection of 20 mg/mL meloxicam at a dose of 0.025 mL/kg in the neck, also administered 10 min before the AD procedure. To avoid subjective bias, the researchers were blinded to the treatment groups. Pain-related behaviors, including tail flicking, head shaking, ear flicking, head rubbing, head crossing bar, and kicking, were observed, and physiological parameters, including heart rate, rectal temperature, respiration rate, mechanical nociceptive threshold (MNT), daily active steps, and food intake were monitored. Hematological conditions were determined using enzyme-linked immunosorbent assays and routine blood tests. The data were processed using a generalized linear mixed model (GLMM). The outcomes demonstrated that the AD procedure increased the frequencies of ear flicking and resulted in rises in the respiration rate, heart rate, rectal temperature, and daily active steps. It also led to decreases in total food intake, forage intake, hay intake, MNT, and increased concentrations of prostaglandin E2 (PgE2), interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), nitric oxide (NO), and malondialdehyde, as well as glutathione peroxidase activity. However, calves that received meloxicam treatment showed significant improvements in response to the AD procedure, including lower respiration rates, heart rates, and rectal temperatures; higher MNTs; and lower intermediate cell ratio. They also had higher red blood counts, hemoglobin levels, hematocrit values; larger mean platelet volumes; and lower concentrations of PgE2, IL-1ß, TNF-α, and NO. These results suggest that co-administration of lidocaine and meloxicam may aid in mitigating the adverse impacts induced by the AD procedure on these calves, thereby supporting the use of meloxicam in conjunction with a local anesthetic in AD procedures for calves aged 6 weeks to 6 mo.

Corrigendum: Transcriptome reveals the role of the htpG gene in mediating antibiotic resistance through cell envelope modulation in Vibrio mimicus SCCF01.

[This corrects the article DOI: 10.3389/fmicb.2023.1295065.].

The cAMP Receptor Protein (CRP) of Vibrio mimicus Regulates Its Bacterial Growth, Type II Secretion System, Flagellum Formation, Adhesion Genes, and Virulence.

Vibrio mimicus is a serious pathogen in aquatic animals, resulting in significant economic losses. The cAMP receptor protein (CRP) often acts as a central regulator in highly pathogenic pathogens. V. mimicus SCCF01 is a highly pathogenic strain isolated from yellow catfish; the crp gene deletion strain (Δcrp) was constructed by natural transformation to determine whether this deletion affects the virulence phenotypes. Their potential molecular connections were revealed by qRT-PCR analysis. Our results showed that the absence of the crp gene resulted in bacterial and colony morphological changes alongside decreases in bacterial growth, hemolytic activity, biofilm formation, enzymatic activity, motility, and cell adhesion. A cell cytotoxicity assay and animal experiments confirmed that crp contributes to V. mimicus pathogenicity, as the LD50 of the Δcrp strain was 73.1-fold lower compared to the WT strain. Moreover, qRT-PCR analysis revealed the inhibition of type II secretion system genes, flagellum genes, adhesion genes, and metalloproteinase genes in the deletion strain. This resulted in the virulence phenotype differences described above. Together, these data demonstrate that the crp gene plays a core regulatory role in V. mimicus virulence and pathogenicity.

Injectable Self-Healing Oxidized Starch/Gelatin Hybrid Hydrogel for Preventing Aseptic Loosening of Bone Tissue Engineering.

Aseptic loosening presents a formidable challenge within the realm of bone tissue engineering, playing a pivotal role in the occurrence of joint replacement failures. The development of therapeutic materials characterized by an optimal combination of mechanical properties and biocompatibility is imperative to ensure the enduring functionality of bone implants over extended periods. In this context, this study introduced an injectable, temperature-sensitive irisin/oxidized starch/gelatin hybrid hydrogel (I-OG) system. The hierarchical cross-linked structure endows the I-OG hydrogel with controlled and adjustable physical and chemical properties, making it easy to adapt to different clinical environments. This hydrogel exhibits satisfactory injectable properties, excellent biocompatibility, and good temperature sensitivity. The sol-gel point of the I-OG hydrogel, close to the body temperature, allows it to cushion the shaking of the implant and maintain an intact state during compression of bone tissue. Significantly, the I-OG hydrogel effectively filled the gap between the implant and bone tissue, successfully inhibiting aseptic loosening induced by titanium particles, a result that confirmed the slow release of the irisin protein from the gel. Collectively, the findings from this study strongly support the proposition that functional hydrogels, typified by the I-OG system, hold substantial promise as an accessible and efficient treatment strategy for mitigating aseptic loosening.

Microbiome analysis reveals the intestinal microbiota characteristics and potential impact of Procambarus clarkii.

The intestinal microbiota interacts with the host and plays an important role in the immune response, digestive physiology, and regulation of body functions. In addition, it is also well documented that the intestinal microbiota of aquatic animals are closely related to their growth rate. However, whether it resulted in different sizes of crayfish in the rice-crayfish coculture model remained vague. Here, we analyzed the intestinal microbiota characteristics of crayfish of three sizes in the same typical rice-crayfish coculture field by high-throughput sequencing technology combined with quantitative real-time polymerase chain reaction (qRT-PCR) and enzyme activity, investigating the relationship between intestinal microbiota in crayfish and water and sediments. The results showed that the dominant intestinal microbiota of crayfish was significantly different between the large size group (BS), normal size group (NS), and small size group (SS), where Bacteroides and Candidatus_Bacilloplasma contributed to the growth of crayfish by facilitating food digestion through cellulolysis, which might be one of the potential factors affecting the difference in sizes. Follow-up experiments confirmed that the activity of lipase (LPS) and protease was higher in BS, and the relative expression of development-related genes, including alpha-amylase (α-AMY), myocyte-specific enhancer factor 2a (MEF2a), glutathione reductase (GR), chitinase (CHI), and ecdysone receptor (EcR), in BS was significantly higher than that in SS. These findings revealed the intestinal microbiota characteristics of crayfish of different sizes and their potential impact on growth, which is valuable for managing and manipulating the intestinal microbiota in crayfish to achieve high productivity in practice. KEY POINTS: • Significant differences in the dominant microflora of BS, NS, and SS in crayfish. • Cellulolysis might be a potential factor affecting different sizes in crayfish. • Adding Bacteroides and Candidatus_Bacilloplasma helped the growth of crayfish.

Identification, characterization and the inflammatory regulating effect of NOD1/2 in sturgeon.

As an ancient species with both conservation and commercial value, Sturgeon's inflammatory regulation mechanism is a research point. Nucleotide-binding and oligomerization domain-containing proteins 1 and 2 (NOD1/2) are classical intracellular pattern recognition receptors (PRRs) in immunity of anti-bacterial infection. However, the characterization and function of NOD1/2 in Sturgeon are still unclear. In this study, we analyzed the synteny relationship of NOD1/2 genes between Acipenser ruthenus and representative fishes at the genome-level. Results showed that the ArNOD2 collinear genes pair was present in all representative fishes. The duplicated ArNOD1/2 genes were under purifying selection during evolution as indicated by their Ka/Ks values. To explore the function of NOD1/2, we further investigated their expression patterns and the effects of pathogenic infection, PAMPs treatment, and siRNA interference in Acipenser baerii, the sibling species of A. ruthenus. Results showed that both AbNOD1/2 were expressed at early developmental stages and in different tissues. Pathogenic infection in vivo and PAMPs treatment in vitro demonstrated that AbNOD1/2 could respond to pathogen stimulation. siRNA interference with AbNOD1/2 inhibited expression levels of RIPK2 and inflammatory cytokines compared to the control group after iE-DAP or MDP treatment. This study hinted that the AbNOD1/2 could stimulate the inflammatory cytokines response during evolutionary processes.

A novel SPE-LC-MRM strategy for serum demethylzeylasteral quantitation developed with an 18O-labeled internal standard.

Natural bioactive compounds (NBCs) are widely used in clinical treatment. For example, Tripterygium wilfordii Hook f. is commonly known in China as Lei-Gong-Teng which means thunder god vine. This herb is widely distributed in Eastern and Southern China, Korea, and Japan. The natural bioactive compounds of this herb can be extracted and made into tripterygium glycoside tablets. It is one of the most commonly used and effective traditional Chinese herbal medicines against rheumatoid arthritis (RA), nephrotic syndrome (NS), autoimmune hepatis (AIH), and so on. However, many NBCs are difficult to reliably quantify in the serum due to the effects of matrix and RSD. In addition, the targeted compound's internal standard (IS) is rarely sold due to the complex isotope internal standard synthesis pathway. In this study, a new quantitation method for 18O labeling combined with off-line SPE was formulated. We contrasted the recoveries and matrix effects of various separation methods in order to choose the best method. Furthermore, we optimized the conditions for SPE loading and washing. An isotopic internal standard was prepared by the 16O/18O exchanging reaction in order to eliminate the matrix effects. The method's accuracy and precision met the requirements for method validation. The recovery of this method was close to 60%. The relative standard deviation (RSD) of the high-concentration sample was 2%, and the limit of detection (LOD) was 1 ng/mL. This method could be used to analyze the clinical serum concentration of demethylzeylasteral. Sixty samples were collected from 10 patients with diabetes nephropathy. The quantitation results of demethylzeylasteral in patients' serum obtained using this method exhibited a correlation between therapeutic drug monitoring (TDM) and decreased urinary protein. This work may have broad implications for the study of drug metabolism in vivo and the clinical application of low-abundance and difficult-to-quantify NBCs.

Resolvin and lipoxin metabolism network regulated by Hyssopus Cuspidatus Boriss extract in asthmatic mice.

Resolvin (Rv) and lipoxin (Lx) play important regulative roles in the development of several inflammation-related diseases. The dysregulation of their metabolic network is believed to be closely related to the occurrence and development of asthma. The Hyssopus Cuspidatus Boriss extract (SXCF) has long been used as a treatment for asthma, while the mechanism of anti-inflammatory and anti-asthma action targeting Rv and Lx has not been thoroughly investigated. In this study, we aimed to investigate the effects of SXCF on Rv, Lx in ovalbumin (OVA)-sensitized asthmatic mice. The changes of Rv, Lx before and after drug administration were analyzed based on high sensitivity chromatography-multiple response monitoring (UHPLC-MRM) analysis and multivariate statistics. The pathology exploration included behavioral changes of mice, IgE in serum, cytokines in BALF, and lung tissue sections stained with H&E. It was found that SXCF significantly modulated the metabolic disturbance of Rv, Lx due to asthma. Its modulation effect was significantly better than that of dexamethasone and rosmarinic acid which is the first-line clinical medicine and the main component of Hyssopus Cuspidatus Boriss, respectively. SXCF is demonstrated to be a potential anti-asthmatic drug with significant disease-modifying effects on OVA-induced asthma. The modulation of Rv and Lx is a possible underlying mechanism of the SXCF effects.

Genotype diversity and antibiotic resistance risk in Aeromonas hydrophila in Sichuan, China.

Sichuan is a significant aquaculture province in China, with a total aquaculture output of 1.72 × 106 tons in 2022. One of the most significant microorganisms hurting the Sichuan aquaculture is Aeromonas hydrophila, whose genotype and antibiotic resistance are yet unknown. This study isolated a total of 64 strains of A. hydrophila from various regions during September 2019 to June 2021 within Sichuan province, China. The technique of Multi-Locus Sequence Typing (MLST) was used for the purpose of molecular typing. Meanwhile, identification of antibiotic resistance phenotype and antibiotic resistance gene was performed. The findings of the study revealed that 64 isolates exhibited 29 sequence types (ST) throughout different regions in Sichuan, with 25 of these ST types being newly identified. Notably, the ST251 emerged as the predominant sequence type responsible for the pandemic. The resistance rate of isolated strains to roxithromycin was as high as 98.3%, followed by co-trimoxazole (87.5%), sulfafurazole (87.5%), imipenem (80%), amoxicillin (60%), and clindamycin (57.8%). Fifteen strains of A. hydrophila exhibited resistance to medicines across a minimum of three categories, suggesting the development of multidrug resistance in these isolates. A total of 63 ARGs were detected from the isolates, which mediated a range of antibiotic resistance mechanisms, with deactivation and efflux potentially serving as the primary mechanisms of antibiotic resistance. This study revealed the diversity of A. hydrophila genotypes and the risk of antibiotic resistance in Sichuan, providing reference for scientific and effective control of A. hydrophila infection.

Improved cardioprotective effect of 3-nitro-N-methyl salicylamide solution after a prolonged preservation time of rat heart.

Ischemic reperfusion injury, caused by oxidative stress during reperfusion, is an inevitable outcome of organ transplantation, especially when the organ preservation time is prolonged. Prolonged ischaemic preservation is a valuable technique for improving the success of organ transplantation, but numerous challenges remain. 3-nitro-N-methyl salicylamide (3-NNMS), an inhibitor of mitochondrial electron transport chain complex III, can be used to reduce reactive oxygen species production during blood reperfusion by slowing the electron flow rate of the respiratory chain. Based on this property, a novel preservation solution was developed for the preservation of isolated rat heart and its cardioprotective effect was investigated during an 8-h cold ischaemia preservation time for the first time. For comparison, 3-NNMS was also included in the histidine-tryptophan-ketoglutarate (HTK) solution. Compared to HTK, HTK supplemented with 3-NNMS significantly improved the heart rate of isolated rat hearts after 8 h of cold storage. Both 3-NNMS solution and HTK supplemented with 3-NNMS solution decreased cardiac troponin T and lactate dehydrogenase levels in perfusion fluid and reduced reactive oxygen species and malondialdehyde levels in the myocardium. The 3-NNMS also maintained the membrane potential of myocardial mitochondria and significantly increased superoxide dismutase levels. These results showed that the new 3-NNMS solution can protect mitochondrial and cardiomyocyte function by increasing antioxidant capacity and reducing oxidative stress in cryopreserved rat hearts during a prolonged preservation time, resulting in less myocardial injury and better heart rate.

The potential mechanism of concentrated mannan-oligosaccharide promoting goldfish's (Carassius auratus Linnaeus) resistance to Ichthyophthirius multifiliis invasion.

Because of the low host specificity, Ichthyophthirius multifiliis (Ich) can widely cause white spot disease in aquatic animals, which is extremely difficult to treat. Prior research has demonstrated a considerable impact of concentrated mannan-oligosaccharide (cMOS) on the prevention of white spot disease in goldfish, but the specific mechanism is still unknown. In this study, transcriptome sequencing, histological analysis, immunofluorescence analysis, phagocytosis activity assay and qRT-PCR assay were used to systematically reveal the potential mechanism of cMOS in supporting the resistance of goldfish (Carrasius auratus) to Ich invasion. According to the transcriptome analysis, the gill tissue of goldfish receiving the cMOS diet showed greater expression of mannose-receptor (MRC) related genes, higher phagocytosis activity, up-regulated expression of phagocytosis-related genes and inflammatory-related genes compared with the control, indicating that cMOS can have an effect on phagocytosis and non-specific immunity of goldfish. After the Ich challenge, transcriptome analysis revealed that cMOS fed goldfish displayed a higher level of phagocytic response, whereas non-cMOS fed goldfish displayed a greater inflammatory reaction. Besides, after Ich infection, cMOS-fed goldfish displayed greater phagocytosis activity, a stronger MRC positive signal, higher expression of genes associated with phagocytosis (ABCB2, C3, MRC), and lower expression of genes associated with inflammation (IL-1ß, IL-17, IL-8, TNF-α, NFKB). In conclusion, our experimental results suggest that cMOS may support phagocytosis by binding to MRC on the macrophage cell membrane and change the non-specific immunity of goldfish by stimulating cytokine expression. The results of this study provide new insights for the mechanism of cMOS on parasitic infection, and also suggest phagocytosis-related pathways may be potential targets for prevention of Ich infection.

Effects of leucism on organ development and molecular mechanisms in Northern snakehead (Channa argus) beyond pigmentation alterations.

Leucism, a widespread occurrence observed in Northern snakehead (Channa argus), bestows a striking white jade-like body coloration upon affected individuals and has gained substantial popularity in commercial breeding. While the visible manifestation of leucism in snakeheads is primarily limited to body coloration, it is crucial to explore the potential influence of leucism on organ development and elucidate the underlying molecular mechanisms. Through a comparative analysis of growth differences, our study revealed that at 150 days post-fertilization, the white variety exhibited an 8.5% higher liver index and intestinal index, but experienced a 20% and 38% decreased in spleen index and renal interstitial index, respectively, suggesting an enlarged digestive area but relatively smaller immune tissues. Nonetheless, no significant differences were observed in the intestinal flora between the two varieties, suggesting the exclusion of any exogenous impacts from symbiotic flora on the growth and development of the white variety. Importantly, transcriptome analysis demonstrated that the white variety exhibited higher expression levels of innate immune genes. Furthermore, annotation of the gene sets expressed in the liver and spleen revealed 76 and 35 genes respectively, with the white variety displaying lower expression in genes associated with "Viral protein interaction with cytokine and cytokine receptor", "Protein processing in endoplasmic reticulum", and "TNF signaling pathway", while exhibiting higher expression in "Estrogen signaling pathway". Notably, three genes, namely pcdhf 4, nlrc3 card 15-like, and a pol-like were identified in both the liver and spleen, indicating their potential involvement in altering the development and innate immunity of the white variety. This study reveals the systemic impact of leucism that extends beyond mere pigmentation alterations, highlighting the prominent characteristics of this phenotype and providing a foundation for future molecular breeding programs aimed at enhancing this variety.

Distribution and associations for antimicrobial resistance and antibiotic resistance genes of Escherichia coli from musk deer (Moschus berezovskii) in Sichuan, China.

This study aimed to investigate the antimicrobial resistance (AMR), antibiotic resistance genes (ARGs) and integrons in 157 Escherichia coli (E. coli) strains isolated from feces of captive musk deer from 2 farms (Dujiang Yan and Barkam) in Sichuan province. Result showed that 91.72% (144/157) strains were resistant to at least one antimicrobial and 24.20% (38/157) strains were multi-drug resistant (MDR). The antibiotics that most E. coli strains were resistant to was sulfamethoxazole (85.99%), followed by ampicillin (26.11%) and tetracycline (24.84%). We further detected 13 ARGs in the 157 E. coli strains, of which blaTEM had the highest occurrence (91.72%), followed by aac(3')-Iid (60.51%) and blaCTX-M (16.56%). Doxycycline, chloramphenicol, and ceftriaxone resistance were strongly correlated with the presence of tetB, floR and blaCTX-M, respectively. The strongest positive association among AMR phenotypes was ampicillin/cefuroxime sodium (OR, 828.000). The strongest positive association among 16 pairs of ARGs was sul1/floR (OR, 21.667). Nine pairs positive associations were observed between AMR phenotypes and corresponding resistance genes and the strongest association was observed for CHL/floR (OR, 301.167). Investigation of integrons revealed intl1 and intl2 genes were detected in 10.19% (16/157) and 1.27% (2/157) E. coli strains, respectively. Only one type of gene cassettes (drA17-aadA5) was detected in class 1 integron positive strains. Our data implied musk deer is a reservoir of ARGs and positive associations were common observed among E. coli strains carrying AMRs and ARGs.

Spring Viremia of Carp Virus Infection Induces Carp IL-10 Expression, Both In Vitro and In Vivo.

Interleukin-10 (IL-10) is a pleiotropic cytokine with both immune enhancement and immunosuppression activities, but the main role is immunosuppression and anti-inflammatory ability. In order to use the immunosuppressive function of IL-10, many viruses, such as SARS-CoV-2, hepatitis B virus and EB virus, can evade the host's immune surveillance and clearance by increasing the expression of host IL-10. However, it has not been reported whether the aquatic animal infection virus can upregulate the expression of host IL-10 and the mechanisms are still unknown. Spring viremia of carp (SVC) is a fatal viral disease for many fish species and is caused by spring viremia of carp virus (SVCV). This disease has caused significant economic losses in the aquaculture industry worldwide. In this study, the expression of carp IL-10 with or without infection of SVCV in epithelioma papulosum cyprinid (EPC) cells, carp head kidney (cHK) primary cells and common carp tissues were analyzed using RT-PCR and ELISA. The results show that SVCV infection induced carp IL-10 mRNA and protein expression, both in vitro and in vivo. However, the upregulation of carp IL-10 by SVCV was hindered by specific inhibitors of the JAK inhibitor (CP-690550), STAT3 inhibitor (STA-21), NF-κB inhibitor (BAY11-7082) and p38 MAPK (mitogen-activated protein kinase) inhibitor (SB202190), but not JNK inhibitor (SP600125). Furthermore, the results demonstrated that JAK1, JAK2, JAK3, TYK2 and STAT5 played important roles in carp IL-10 production induced by SVCV infection. Taken together, SVCV infection significantly induced carp IL-10 expression and the upregulation trigged in JAK-STAT, NF-κB and p38MAPK pathways. To our knowledge, this is the first time that a fish infection virus upregulated the host IL-10 expression through the JAK-STAT, NF-κB and p38MAPK pathways. Altogether, fish viruses may have a similar mechanism as human or other mammalian viruses to escape host immune surveillance and clearance.