Durable Antimicrobial Microstructure Surface (DAMS) Enabled by 3D-Printing and ZnO Nanoflowers.

A. Numerous studies have been trying to create nanomaterials based antimicrobial surfaces to combat the growing bacterial infection problems. Mechanical durability has become one of the major challenges to applying those surfaces in real life. In this study, we demonstrate the Durable Antimicrobial Microstructures Surface (DAMS) consisting of DLP 3D printed microstructures and zinc oxide (ZnO) nanoflowers. The microstructures serve as a protection armor for the nanoflowers during abrasion. The antimicrobial ability was tested by immersing in 2E8 CFU/mL Escherichia coli ( E. coli ) suspension and then evaluated using electron microscopy. Compared to the bare control, our results show that the DAMS reduces bacterial coverage by more than 90% after 12 hrs of incubation and approximately 50% after 48 hrs of incubation before abrasion. Importantly, bacterial coverage is reduced by approximately 50% after 2 min of abrasion with a tribometer, and DAMS remains effective even after 6 min of abrasion. These findings highlight the potential of DAMS as an affordable, scalable, and durable antimicrobial surface for various biomedical applications.

Highly Hydrophilic Zirconia Composite Anion Exchange Membrane for Water Electrolysis and Fuel Cells.

To prepare anion exchange membranes with high water electrolysis and single fuel cell performance, an inorganic-organic composite (IOC) strategy with click cross-linked membranes coated with different contents of hydrophilic polar nanozirconia is proposed to fabricate composite membranes (CM) PBP-SH-Zrx. The performance test results showed that the CM PBP-SH-Zr4 not only has good through-plane ionic conductivity (167.7 mS cm-1, 80 °C), but also exhibits satisfactory dimensional stability (SR 16.5%, WU 206.4%, 80 °C), especially demonstrating excellent alkaline stability with only 16% degradation (2 M NaOH for 2200 h). In water electrolysis, the "microgap" between the membrane and catalyst layer (solid-solid interface) is alleviated, and the membrane electrode assembly (MEA) interfacial compatibility (liquid-solid-solid interface) is enhanced. The CM PBP-SH-Zr4 showed the lowest charge transfer resistance (Rct, 0.037 Ω cm2) and a high current density of 2.5 A cm-2 at 2.2 V, while the voltage drop was 0.361 mV h-1 after 360 h of endurance (six start-stop cycles) at 60 °C and 500 mA cm-2, proving a good water electrolysis durability. Moreover, an acceptable peak power density of 0.464 W cm-2 at 80 °C is achieved in a H2/O2 fuel cell with a PBP-SH-Zr4-AEM. Therefore, the IOC strategy can enhance the membrane's comprehensive performance and interface compatibility of MEA and may promote the development of anion exchange membranes (AEMs) for water electrolysis and fuel cells.

Mechanism of Chinese sturgeon IFN-γ inhibition on Mycobacterium marinum (Acipenser sinensis).

IFN-γ plays a crucial role in both innate and adaptive immune responses and is a typical Th1 cytokine that promotes Th1 response and activates macrophages. When macrophages were incubated with IFN-γ, their phagocytosis ratio against Mycobacterium marinum increased significantly, as observed under fluorescence microscopy. The macrophages engulfed a large number of M. marinum. The proliferative ability of macrophages treated with IFN-γ was significantly weaker on the 4th and 7th day after phagocytosis and subsequent re-infection with marine chlamydia (P < 0.001). This suggests that IFN-γ enhances the phagocytosis and killing ability of macrophages against M. marinum. IFN-γ protein also significantly increased the production of reactive oxygen species (H2O2) and nitric oxide (NO) by macrophages. Additionally, the expression levels of toll-like receptor 2 (tlr2) and caspase 8 (casp8) were significantly higher in macrophages after IFN-γ incubation compared to direct infection after 12 h of M. marinum stimulation. Apoptosis was also observed to a higher degree in IFN-γ incubated macrophage. Moreover, mRNA expression of major histocompatibility complex (MHC) molecules produced by macrophages after IFN-γ incubation was significantly higher than direct infection. This indicates that IFN-γ enhances antigen presentation by upregulating MHC expression. It also upregulates tlr2 and casp8 expression through the TLR2 signaling pathway to induce apoptosis in macrophages. The pro-inflammatory cytokine showed an initial increase followed by a decline, suggesting that IFN-γ enhances the immune response of macrophages against M. marinum infection. On the other hand, the anti-inflammatory cytokine showed a delayed increase, significantly reducing the expression of pro-inflammatory cytokines. The expression of both cytokines balanced each other and together regulated the inflammatory reaction against M. marinum infection.

Twisted Poly(p-terphenyl-co-m-terphenyl)-Based Anion Exchange Membrane for Water Electrolysis.

In order to improve the mechanical and water electrolysis performance of anion exchange membranes (AEMs), we adjusted the ratio between p-terphenyl and m-terphenyl to balance the backbone conformation, which gives it a better suitability for a better combination with cations. The results showed that poly(m-terphenyl-co-p-terphenyl)-based AEMs have excellent mechanical properties. Among them, the m-p-TP-40-BOP-ASU membrane has the highest tensile strength and elongation at break (75.72 MPa and 16.07%). The ionic conductivity reaches 137.14 mS cm-1 at 80 °C owing to the fact that efficient ion-conducting channels are formed by well-balanced molecular structures. The current density of the m-p-TP-40-BOP-ASU membrane reached 1.96 A cm-2 (1 M KOH aq, 2.0 V and 60 °C). After testing for 112 h under a current density of 500 mA cm-2, the voltage increased by 102 mV compared to the initial electrolysis voltage. All results have shown that m-p-TP-x-BOP-ASU has excellent electrolysis performance and electrochemical durability and has a promising application prospect in AEM water electrolyzers.

Functional characterization of group â ¡ interferon, IFNf in the acipenseriform fish, Chinese sturgeon (Acipenser sinensis).

Teleost fish possess a diversity of type Ⅰ interferons (IFNs) repertoire, which play a crucial role in antiviral and antimicrobial immune responses. In our previous study, IFNe1-3 and IFNb were identified and cloned from Chinese sturgeon (Acipenser sinensis), an acipenseriform fish. However, the absence of Chinese sturgeon genome data has left the question of whether there are other type Ⅰ IFN members in this species unresolved. In this study, we have identified and characterized a novel IFN, IFNf in Chinese sturgeon (AsIFNf). Bioinformatics analysis revealed that the AsIFNf contains a unique disulfide bond (2 cysteines) located in the second exon and fifth exon region, distinguishing it from other reported teleost type I IFNs. Meanwhile, qPCR results showed that AsIFNf mRNA was detectable in all examined tissues and up-regulated in the spleen or kidney in response to poly I: C, Citrobacter freundii, and Spring Viremia of Carp Virus (SVCV), but not by LPS. Furthermore, compared to recombinant AsIFNe2 protein (rAsIFNe2), rAsIFNf exhibited a stronger protective effect on Chinese sturgeon fin cells against SVCV and also induced higher expression of antiviral genes Mx and viperin. Importantly, AsIFNf displayed characteristics similar to antimicrobial peptides (AMPs) with a positive charge and demonstrated a broad spectrum of antimicrobial activity in vitro. These findings provide a theoretical foundation for understanding the primitive structure and function of interferon, as well as deepening our comprehension of the innate immune system and disease defense in the endangered Chinese sturgeon.

Hydrophilic Chitosan-Doped Composite Diaphragm Reducing Gas Permeation for Alkaline Water Electrolysis Producing Hydrogen.

The present paper studied the chitosan-doped composite diaphragm by the phase exchange method with the objective of developing a composite diaphragm that complies with the alkaline water electrolysis requirements, as well as tested the electrolytic performance of the diaphragm in alkaline water electrolysis. The structure and morphology are characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The performance of chitosan-doped composite diaphragms was tested; CS3Z12 composite diaphragm with a low area resistance (0.20 Ω cm2), a high bubble point pressure (2.75 bar), and excellent electrochemical performance (current density of 650 mA cm-2 at 1.83 V) shows the best performance. Moreover, the performance of the synthesized composite diaphragm is significantly elevated compared to commercial diaphragms (Zirfon PERL), which is promising for practical application in alkaline electrolytic cells.

Jasmonate signaling drives defense responses against Alternaria alternata in chrysanthemum.

BACKGROUND: Black spot disease caused by the necrotrophic fungus Alternaria spp. is one of the most devastating diseases affecting Chrysanthemum morifolium. There is currently no effective way to prevent chrysanthemum black spot. RESULTS: We revealed that pre-treatment of chrysanthemum leaves with the methy jasmonate (MeJA) significantly reduces their susceptibility to Alternaria alternata. To understand how MeJA treatment induces resistance, we monitored the dynamics of metabolites and the transcriptome in leaves after MeJA treatment following A. alternata infection. JA signaling affected the resistance of plants to pathogens through cell wall modification, Ca2+ regulation, reactive oxygen species (ROS) regulation, mitogen-activated protein kinase cascade and hormonal signaling processes, and the accumulation of anti-fungal and anti-oxidant metabolites. Furthermore, the expression of genes associated with these functions was verified by reverse transcription quantitative PCR and transgenic assays. CONCLUSION: Our findings indicate that MeJA pre-treatment could be a potential orchestrator of a broad-spectrum defense response that may help establish an ecologically friendly pest control strategy and offer a promising way of priming plants to induce defense responses against A. alternata.

Studies on the Platinum Thick Film Sensor Conformally Written by Laser Micro-Cladding: Formability, Microstructure, and Performance.

In this paper, laser micro-cladding technology (LMC) was conducted to prepare high-temperature Pt thick film sensors in situ. The formability, microstructure, sintering mechanism, and electrical properties of the LMCed Pt thick films were first studied systematically. Results indicated that with the increase of laser power density, the sintering degree of the Pt thick film increased obviously, improving its adhesion strength and reducing its resistivity. However, when the laser power density exceeded the threshold, holes or grooves were formed in the Pt film, leading to the degeneration of its properties. A Pt thick film with good adhesion strength, excellent conductive networks, and the minimum resistivity (46 ± 2 µΩ·cm) was obtained at a laser power density of 1.37 × 106 W·cm-2. Then, Pt thick film temperature sensors (including Pt thermal resistance temperature (RTD) and Pt-Pt10%Rh thermocouple sensors) were conformally prepared by LMC. Their temperature-sensing performance became stable after the initial high-temperature calibration, with a linearity of 0.9985 for the RTD with a TCR of 2.46 × 10-3/°C (at 920 °C) and a linearity of 0.9905 for the thermocouple with a Seebeck coefficient of 9.7 µV/°C, both of which are better than that made by direct DC magnetron sputtering deposition. Therefore, this work provides a novel feasible way to conformally integrate high-performance Pt film sensors in situ.

Pathogenicity of Plesiomonas shigelloides and Citrobacter freundii isolated from the endangered Chinese sturgeon (Acipenser sinensis).

Chinese sturgeon (Acipenser sinensis) is an indigenous species of China and is listed as a critically endangered species. Recently, second filial generations of Chinese sturgeon in the Yangtze River Fisheries Research Institute suffered from a severe disease. In this study, two kinds of pathogenic bacteria were isolated from diseased sturgeon and identified as Plesiomonas shigelloides and Citrobacter freundii, based on 16S rDNA gene sequence alignment analysis. Antimicrobial susceptibility testing showed that P. shigelloides was resistant to ampicillin, penicillin, midecamycin, oxacillin, and clindamycin; and sensitive to tocefatriaxone, piperacillin, cefoperazone, cefazolin, and ciprofloxacin. C. freundii was resistant to ampicillin, penicillin, midecamycin, oxacillin, and clindamycin; and sensitive to chloramphenicol, cefuroxime, norfloxacin, ciprofloxacin, and ceftazidime. The median lethal dose (LD50) values of P. shigelloides and C. freundii were 4.50 × 103 colony forming units (CFU)/g and 3.20 × 103 CFU/g, respectively. Clinical symptoms of challenged sturgeons were the same as those of naturally infected sturgeons. Histopathological examination disclosed severe damage in the viscera of P. shigelloides and C. freundii-infected sturgeons. This is the first report suggesting that P. shigelloides infection is associated with mortality of Chinese sturgeon. The results of this study revealed the pathogenesis and severe pathogenicity of P. shigelloides and C. freundii in cultured Chinese sturgeon, and offer insights into the prevention and treatment of bacterial infection caused by P. shigelloides and C. freundii in cultured sturgeons.

Computer vision enabled funnel adapted sensing tube (FAST) for power-free and pipette-free nucleic acid detection.

A simple, portable, and low-cost microfluidic system-funnel adapted sensing tube (FAST) is developed as an integrated, power-free, and pipette-free biosensor for viral nucleic acids. This FAST chip consists of four reaction chambers separated by carbon fiber rods, and the reagents in each chamber are transferred and mixed by manually removing the rods. Rather than using electrical heaters, only a hand warmer pouch is used for an isothermal recombinase polymerase amplification (RPA) and CRISPR-Cas12a reaction. The signal produced by the RPA-CRISPR reaction is observed by the naked eye using an inexpensive flashlight as a light source. The FAST chip is fabricated using water-soluble polyvinyl alcohol (PVA) as a sacrificial core, which is simple and environmentally friendly. Using a SARS-CoV-2 fragment as a target, a ∼10 fM (6 × 103 copies per µL) detection limit is achieved. To generalize standard optical readout for individuals without training, a linear kernel algorithm is created, showing an accuracy of ∼100% for identifying both positive and negative samples in FAST. This power-free, pipette-free, disposable, and simple device will be a promising tool for nucleic acid diagnostics in either clinics or low-resource settings.

The last giants of the Yangtze River: A multidisciplinary picture of what remains of the endemic Chinese sturgeon.

The Chinese sturgeon, an important endemism of the Yangtze River, belongs to 'the most critically endangered group of species' worldwide, with overfishing and habitat destruction being the main drivers towards extinction. Newly obtained microchemical comparisons between animals and water from different river locations revealed a probable shifting of the spawning ground few kilometers downstream compared to the only previously known site, located under the Gezhouba Dam. This offers a glimmer of hope for an adaptive response to habitat perturbation caused by the recently built Three Gorges dam on the Yangtze River. On the other hand, genetic data provide an estimate of about 20 breeders participating in the only significant breeding event of the past 10 years. This warns of a near species extinction forecast if no in situ and ex situ conservation efforts occur promptly. Given these results we propose a list of priority conservation actions that urgently need to be promoted, supported, and put into practice.

Impact of Different Diets on Adult Tri-Spine Horseshoe Crab, Tachypleus tridentatus.

Effective culture and management of adult tri-spine horseshoe crab, Tachypleus tridentatus can ensure that stock enhancement programs and aquaculture systems are maintained. To explore suitable feed for animals during the breeding season, Pacific oyster (Ostrea gigas) (oyster group; OG) and frozen sharpbelly fish (Hemiculter leucisculus) (frozen fish group; FG) were selected to feed 20 T. tridentatus male and female pairs, respectively. At the end of the experiment, intestinal samples were obtained to measure digestive enzymes activities. The intestinal flora were determined by 16S rDNA sequencing. No eggs were observed in the FG and one T. tridentatus adult died. No animals died in the OG, and 9.7 × 104 eggs were obtained. These results show that oysters are more suitable for the development and reproduction of adult T. tridentatus than frozen fish. Additionally, the digestive enzyme activity analysis revealed that animals in the OG exhibited higher protein digestibility than those in the FG, but no significant differences in lipid and carbohydrate uptake were observed between the groups. Furthermore, the intestinal flora analysis showed that operational taxonomic units (OTUs) and the Chao1 index were significantly higher in the OG than in the FG, but no significant difference was observed in the Shannon or Simpson indices between the groups. Our data indicate that the oyster diet improved the intestinal microbial diversity of T. tridentatus. We hypothesize that nutrients, such as oyster-based taurine, proteins, and highly unsaturated fatty acids, improve protease activity in the T. tridentatus digestive tract, alter the intestinal floral structure, and improve the reproductive performance of T. tridentatus.

Pro-angiognetic and pro-osteogenic effects of human umbilical cord mesenchymal stem cell-derived exosomal miR-21-5p in osteonecrosis of the femoral head.

Mesenchymal stem cell (MSC)-derived exosomes (Exos) enhanced new bone formation, coupled with positive effects on osteogenesis and angiogenesis. This study aims to define the role of microRNA (miR)-21-5p delivered by human umbilical MSC-derived Exos (hucMSC-Exos) in the osteonecrosis of the femoral head (ONFH). We first validated that miR-21-5p expression was downregulated in the cartilage tissues of ONFH patients. Besides, hucMSCs delivered miR-21-5p to hFOB1.19 cells and human umbilical vein endothelial cells (HUVECs) through the secreted Exos. Loss- and gain-of-function approaches were performed to clarify the effects of Exo-miR-21-5p, SOX5, and EZH2 on HUVEC angiogenesis and hFOB1.19 cell osteogenesis. It was established that Exo-miR-21-5p augments HUVEC angiogenesis and hFOB1.19 cell osteogenesis in vitro, as reflected by elevated alkaline phosphatase (ALP) activity and calcium deposition, and increased the expression of osteogenesis-related markers OCN, Runx2 and Collagen I. Mechanistically, miR-21-5p targeted SOX5 and negatively regulated its expression, while SOX5 subsequently promoted the transcription of EZH2. Ectopically expressed SOX5 or EZH2 could counterweigh the effect of Exo-miR-21-5p. Further, hucMSC-Exos containing miR-21-5p repressed the expression of SOX5 and EZH2 and augmented angiogenesis and osteogenesis in vivo. Altogether, our study uncovered the role of miR-21-5p shuttled by hucMSC-Exos, in promoting angiogenesis and osteogenesis, which may be a potential therapeutic target for ONFH.

Transcriptome Sequencing Reveals the Antiviral Innate Immunity by IFN-γ in Chinese Sturgeon Macrophages.

To further study the biological function of interferon-gamma (IFN-γ) in the Chinese sturgeon (Acipenser sinensis), we conducted a transcriptome analysis of primary macrophages induced by IFN-γ using Illumina sequencing technology. We obtained 88,879 unigenes, with a total length of 93,919,393 bp, and an average length of 1,057bp. We identified 8,490 differentially expressed genes (DEGs) between the untreated and IFN-γ-treated macrophages, with 4,599 upregulated and 3,891 downregulated. Gene ontology (GO) analysis showed that 4,044 DEGs were enriched in the biological, cellular components, and molecular function categories. Kyoto Encyclopedia of Genes and Genomes (KEGG) identified 278 immunity-related pathways enriched for the DEGs. According to the GO enrichment results, eight key immunity-related genes were screened for verification using qPCR. Results indicate that IFN-γ can activate macrophage Interferon Regulatory Factors (IRFs) and type I interferon (IFN-I), activate RIG-I-like and Toll-like receptor-related pathways, and improve the antiviral ability of macrophages in Chinese sturgeon.

Understanding microbeads stacking in deformable Nano-Sieve for Efficient plasma separation and blood cell retrieval.

Efficient separation of blood cells and plasma is key for numerous molecular diagnosis and therapeutics applications. Despite various microfluidics-based separation strategies having been developed, there is still a need for a simple, reliable, and multiplexing separation device that can process a large volume of blood. Here we show a microbead-packed deformable microfluidic system that can efficiently separate highly purified plasma from whole blood, as well as retrieve blocked blood cells from the device. To support and rationalize the experimental validation of the proposed device, a highly accurate model is constructed to help understand the link between the mechanical properties of the microfluidics, flow rate, and microbeads packing/leaking based on the microscope imaging and the optical coherence tomography (OCT) scanning. This deformable nano-sieve device is expected to offer a new solution for centrifuge-free diagnosis and treatment of bloodborne diseases and contribute to the design of next-generation deformable microfluidics for separation applications.

Comprehensive comparison of thirteen kinds of cytokine receptors from the endangered fish Chinese sturgeon (Acipenser sinensis).

The interferon receptor system in teleost fish is more complex than that in mammals. In the present study, we identified 13 cytokine receptor genes (10 interferon receptor genes and 3 IL10R2-like genes) from Chinese sturgeon (Acipenser sinensis) using RNA-sequencing. Sequence analysis indicated that these receptors had conserved domains, including signal peptides, FNⅢ, and transmembrane domains. Phylogenetic analysis suggested that they belonged to the cytokine receptor family. In the present study, we named them IFNAR1-like (CRFB5a, CRFB5b), IFNAR2-like (CRFB3a, CRFB3b), IFNGR1-like (IFNGR1), IFNGR2-like (CRFB6a, CRFB6b/IFNGR2-1, CRFB6c/IFNGR2-2, CRFB6d/IFNGR2-3, CRFB6e/IFNGR2-4) and IL10R2-like (CRFB4a, CRFB4b, CRFB4c), respectively. Constitutive expression analysis revealed that these receptor genes had potential functions in immune and non-immune tissue compartments. After stimulating with Poly (I:C), the expression fold changes of CRFB3a, CRFB4a, CRFB4b, CRFB5b, and CRFB6e/IFNGR2-4 in Chinese sturgeon were higher than those of other receptor genes, which revealed that these five genes had important functions in the immune process to resist virus invasion in the host. After stimulating with IFN gamma, the expression fold changes of CRFB3a, CRFB4a, and CRFB6b/IFNGR2-1 were higher than those other receptor genes. Based on other teleost fish interferon receptor models, we speculated that IFNAR1-like (CRFB5a, CRFB5b) and IFNAR2-like (CRFB3a, CRFB3b), comprised Chinese sturgeon type Ⅰ IFN receptors; and IFNGR1-like (IFNGR1) and IFNGR2-like (CRFB6/IFNGR2) comprised Chinese sturgeon type Ⅱ IFN receptors.

Is repeated retreatment necessary for HIV-negative serofast early syphilis patients?

A persistent non-treponemal serological response can be observed in patients with syphilis after treatment and is referred to as serofast. This status makes it difficult for clinicians to judge the curative effect of treatment, particularly in patients with early syphilis. In the present study, a total of 114 eligible serofast patients treated between January 2009 and June 2016 were retrospectively analyzed. All patients were subjected to rapid plasma reagin (RPR) serological tests and followed up for 24 months. The patients who remained serofast after initial therapy were given the first retreatment, and at 12 months, those who were still serofast received a second retreatment. After the first retreatment (6 months), 33.3% of the subjects (38/114) were serologically cured (≥4-fold decline in RPR titer). At 24 months, the patients that had achieved serological cure accounted for 23.7% (18/76) of the patients that received the second retreatment. Furthermore, 26.3% of subjects that achieved serological cure (10/38) and had not been further treated after the first retreatment spontaneously presented with a ≥4-fold decline in RPR titer or negative status. In conclusion, the present study indicated that in patients with early syphilis and serofast status after initial treatment, retreatments may not provide any significant benefit. The second retreatment did not significantly improve the patient's serological cure rate. There is no evidence that patients with early syphilis and serofast should receive multiple retreatments, in spite of this being commonly performed in clinical practice.

Evaluation of the potential probiotic Bacillus subtilis isolated from two ancient sturgeons on growth performance, serum immunity and disease resistance of Acipenser dabryanus.

In the present study, we aimed to screen the potential probiotic Bacillus subtilis isolated from the gut of healthy fish using in vitro assays and to evaluate its effect on Dabry's sturgeon (Acipenser dabryanus) using in vivo feeding experiments. Among the isolates, B. subtilis BSth-5 and BSth-19 exhibited antimicrobial effect against four sturgeon-pathogenic bacteria, including Aeromonas hydrophila, A. veronii, A. media, and Streptococcus iniae. The cell number of B. subtilis BSth-5 and BSth-19 changed little after 2 h of exposure to pH 3.0 or fresh Dabry's sturgeon bile at 2.5% and 5.0%. Meanwhile, B. subtilis BSth-5 and BSth-19 produced extracellular protease, cellulose, and lipase. And it was proved that B. subtilis BSth-5 and BSth-19 were harmless after injection of Dabry's sturgeon. One group of Dabry's sturgeon was fed a control diet and two groups were fed experimental diets containing 2.0 × 108 CFU/g BSth-5 (T1 group) or BSth-19 (T2 group) for 8 weeks. No significant differences in final weight, weight gain rate, and special growth rate were observed in the T1 and T2 groups compared to the control group (P > 0.05), but a significant improvement in survival rate was detected after 4 and 8 weeks of feeding (P < 0.05). After 8 weeks, serum total antioxidant capacity, total superoxide dismutase activity, and IgM levels were significantly higher in the T1 and T2 groups compared to the control group (P < 0.05). Moreover, serum lysozyme activity was significantly higher in the T1 group relative to the control group during the whole experiment period (P < 0.05); however, the differences were not significant between the T2 and control groups (P > 0.05). Serum malondialdehyde levels in the T1 and T2 groups were significantly lower than those in the control group after 4 weeks (P < 0.05). Sturgeons in the T1 and T2 groups showed a higher survival rate after Aeromonas hydrophila infection. To summarize, dietary supplementation with BSth-5 and BSth-19 could enhance the survival rate, antioxidant activity, serum immunity, and disease resistance in A. dabryanus.

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.