Animal reproduction is closely linked to energy metabolism, and ovarian glycolipid metabolism disorders can lead to follicular abnormalities, reduced fertility, and infertility. Granulosa cells (GCs), as key energy suppliers in the ovary, directly influence oocyte development, hormone secretion, and reproductive function. However, the interaction between reproductive regulatory factors and ovarian energy metabolism is unclear. Our prior studies showed that gonadotropin-inhibitory hormone (GnIH) causes ovarian degeneration and glycolipid metabolism disorders in female piglets, but its ovarian-level mechanism remains unknown. We explored GnIH's effects on porcine ovarian and GC glycolipid metabolism via in vivo and in vitro experiments. In vivo, intraperitoneal GnIH (0.1, 1 mg/mL) administered for 14 days inhibited glucose transport and gluconeogenesis, but promoted glycolysis, fatty acid synthesis, and β-oxidation. It inhibited the AKT-GSK-3β pathway and activated AMPK, causing abnormal glucose to use and ATP deficiency. Metabolomics showed increased adenosine and D-glyceroldehyde 3-phosphate, and decreased citrate, glucuronic acid, and testosterone. In vitro, transcriptomics revealed 5253 differentially expressed genes (956 glycolipid-related) in GnIH-treated GCs, enriched in Wnt and AMPK pathways. GnIH promoted glucose transport, glycolysis, and glycogen synthesis while simultaneously inhibiting mitochondrial ATP synthesis - effects that were closely associated with the activation of the Wnt signaling pathway and the inhibition of the AMPK pathway. GnIH inhibited AMPK and activated Wnt, promoting glucose transport and glycolysis but suppressing mitochondrial ATP synthesis. Furthermore, functional intervention experiments demonstrated that GnIH effectively reversed the metabolic effects induced by either the AMPK activator AICAR or the Wnt inhibitor IWP2 in GCs, reinforcing that GnIH acts as a dominant regulator upstream of both pathways. In addition, GnIH exacerbated oxidative stress, induced insulin resistance, and disrupted mitochondrial dynamics. In conclusion, GnIH disrupts energy metabolism via Wnt and AMPK pathways, causing GC glycolipid disorders and dysfunction, offering new targets for reproductive disorder interventions.

Pasteurella multocida is the main pathogen causing fowl cholera and poses a serious threat to the poultry industry. Current clinical control relies on antibiotics, but the prevalence of drug-resistant strains makes it urgent to develop new antibacterial strategies. In this study, a P. multocida-specific bacteriophage vB_PmuS_ZP41 was isolated and identified as a member of the family Siphoviridae by transmission electron microscopy. This phage showed lytic activity against 13 out of 19 clinical isolates of P. multocida (68.4%) and remained stable at 4-50°C and pH 3-9. The optimal multiplicity of infection was 0.01, with a latent period of 10 min and a burst size of approximately 56 PFU/cell. Whole-genome sequencing revealed that the phage genome is a double-stranded DNA of 38,592 bp, containing no virulence genes or antibiotic resistance genes, indicating good safety. In a chick infection model, phage treatment significantly improved the survival rate of infected chicks from 40% to 80%, significantly reduced bacterial loads in blood, lung, liver, and spleen, and decreased serum levels of TNF-α and IL-1β while alleviating histopathological damage. This study systematically characterized the biological properties of phage vB_PmuS_ZP41 and its antibacterial efficacy both in vitro and in vivo, providing an experimental basis and a candidate strain for the future development of phage therapy against avian pasteurellosis.

Avian colibacillosis caused by avian pathogenic Escherichia coli (APEC) results in high mortality and substantial economic losses in poultry production. Phage therapy represents a promising alternative strategy for controlling bacterial infections. In this study, we isolated the high-titer lytic APEC phage YX22 from poultry farm sewage, and evaluated its therapeutic potential in an experimental APEC infection model. Phage YX22 showed a short latent period of 10 min, a burst size of 158 PFU/cell, and stability across pH 4-10 and 30-60°C for 1 h. Transmission electron microscopy and whole-genome analysis indicated that YX22 belonged to the family Ackermannviridae and the AG3-like virus group. An experimental infection model was established in chicks using APEC strain IMT5155 to compare the effects of nebulized and oral phage administration. YX22 treatment reduced clinical symptom scores, tissue bacterial loads, and lung lesions in infected chicks. The survival rate of chicks receiving nebulized YX22 was 80%, compared with 70% in the oral phage and gentamicin groups and 53.33% in the APEC-challenged control group. Phage recovery assays showed that nebulized YX22 was detected in the respiratory tract within 3 h and in all tested tissues within 10 h. At 10 h after administration, YX22 titers in the lungs and spleen were higher after nebulized administration than after oral administration. These findings suggest that nebulized YX22 has therapeutic potential against experimental avian colibacillosis caused by APEC strain IMT5155, but further studies under production conditions are required.

Bacteriophage endolysins can specifically bind to and efficiently lyse host bacteria, and therefore considered promising alternatives to antibiotics. Natural endolysins, however, often have limitations such as a narrow lytic spectrum or low lytic activity, which restrict their broader application in food antibacterial control. In this study, a recombinant endolysin JD007-LY01 with a stable protein structure was constructed by fusing the binding domain of the native endolysin LY01 with the lytic domain of the exogenous endolysin JD007. Experimental results showed that JD007-LY01 lysed all Staphylococcus aureus strains and exhibited a broader lytic spectrum than LY01. The recombinant enzyme displayed optimal activity at pH 6-8 and maintained high activity at temperatures between 4°C and 40°C. In artificially contaminated milk and pork models, JD007-LY01 produced moderate reductions in viable methicillin-resistant S. aureus (MRSA) counts. It also reduced biofilm-associated cell counts on polystyrene and stainless steel surfaces. Collectively, these results indicate that JD007-LY01 exhibits improved lytic activity and a broader spectrum compared with LY01, supporting the feasibility of domain recombination as a strategy to enhance certain antibacterial properties of endolysins.

Thyroid disorders profoundly disrupt metabolism, development, growth, pubertal timing, and fertility in domestic animals. Gonadotropin-inhibitory hormone (GnIH), a key inhibitory neuropeptide regulating reproductive function, has been implicated in metabolic dysfunction-associated infertility as well as thyroid dysfunction-related pubertal abnormalities. These observations suggest potential crosstalk between GnIH and thyroid hormones (THs), positioning GnIH as a possible integrative regulator linking the hypothalamic-pituitary-thyroid (HPT) and hypothalamic-pituitary-gonadal (HPG) axes. However, the role of GnIH in the modulation of thyroid function remains poorly defined. Using the pig as a translationally relevant model for neuroendocrine research, we investigated the peripheral effects of GnIH on TH synthesis and elucidated the underlying mechanisms in female piglets. Untargeted metabolomic analysis revealed a significant reduction in serum thyroxine levels following chronic intraperitoneal administration of GnIH compared with vehicle-treated controls. Furthermore, colocalization and pharmacological analyses demonstrated that peripheral GnIH directly suppresses TH synthesis in the thyroid gland, leading to decreased circulating TH levels and activation of the negative feedback regulation within the HPT axis. These results suggest that the thyroid gland is a primary peripheral target for GnIH-induced hypothyroidism. Subsequent in vivo and in vitro studies confirmed that peripheral GnIH disrupts mitochondrial function, inducing apoptosis and oxidative stress in thyroid follicular epithelial cells and ultimately causing hypothyroidism, while its effects on proliferation followed an opposite trend. These results establish that GnIH directly inhibits TH synthesis through mitochondrial dysfunction and follicular epithelial cell apoptosis, thereby contributing to hypothyroidism pathogenesis. Our study identifies GnIH as a novel neuroendocrine regulator of thyroid function and suggests that GnIH agonists or antagonists may offer therapeutic potential for thyroid disorders and related conditions.

Heat stress (HS) impairs boar reproductive capacity via damaging Sertoli cells (SCs) and disrupting the integrity of the blood–testis barrier (BTB). This present study investigated the protective effects and underlying molecular mechanisms of PTD-FNK against HS-induced injury in porcine SCs. A HS model (43 °C, 1 h) was established, and 0.1 nM was determined as the optimal working concentration of PTD-FNK. Results showed that PTD-FNK effectively reversed HS-induced BTB disruption by restoring the expression levels of tight junction proteins (Claudin-1, Occludin, ZO-1, and Cx43) to baseline levels (p < 0.05). Concurrently, PTD-FNK alleviated HS-induced oxidative stress by enhancing total antioxidant capacity (T-AOC) and superoxide dismutase (SOD) activity, while reducing malondialdehyde (MDA) content (p < 0.05). It also suppressed HS-triggered apoptosis by downregulating the expression of pro-apoptotic proteins (Caspase-3/8/9 and Bax) and upregulating the anti-apoptotic protein Bcl-2 (p < 0.05). Furthermore, PTD-FNK maintained cellular homeostasis by regulating mitochondrial dynamics—restoring mitochondrial membrane potential (MMP) and balancing the expression of fusion-related protein Mfn1 and fission-related protein Drp1.Transcriptomic and LY294002 experiments confirmed PTD-FNK exerted effects via the PI3K/AKT pathway, modulating ID3, H2AX, DDIT3, CDKN1C, RAD51, and TP53. Thus, PTD-FNK protects SCs from HS through multi-target regulation dependent on PI3K/AKT, providing a novel strategy for boar reproductive health under HS.

Porcine dermatitis caused by Staphylococcus aureus (S. aureus) has garnered increasing attention due to the escalating antibiotic resistance, necessitating the development of alternative therapeutic strategies. In this study, a S. aureus-lytic jumbo phage, designated as LY01, was isolated from swine farm effluent and subsequently characterized. Key findings revealed that the bacteriophage exhibited lytic activity against S. aureus with broad host specificity. LY01 possesses a short latent period (30 min), thermal stability (30°C-50°C), and pH stability (pH 5-9). Phylogenetic analysis based on genomic sequencing, combined with electron microscopy for morphological observation, classified LY01 within the phylum Uroviricota and class Caudoviricetes. Furthermore, the therapeutic effect of phage LY01 on swine dermatitis was assessed by evaluating the severity of dermatitis lesions, histopathology, hematology, changes in inflammatory factors, and microbial diversity. The in vivo results showed that local LY01 therapy significantly decreased skin bacterial loads, cutaneous inflammatory responses, and blood leukocyte counts, while improving the skin tissue-associated bacteria composition and alleviating histopathological injury in dermal samples. These findings indicate that local application of LY01 on S. aureus-induced dermatitis lesions is associated with clinical improvement, which provides a promising approach to address antibiotic resistance in treating S. aureus-induced skin infections.

Energy metabolism is crucial for reproduction, and disturbances in glucose metabolism are closely associated with reproductive disorders. The gonadotropin inhibitory hormone (GnIH) plays a crucial role in reproduction and glucose homeostasis in both birds and mammals. However, its specific effects on glucose metabolism-associated ovarian dysfunction in hens remain uncharacterized. In this study, we investigated the effects of GnIH on ovarian function and glucose homeostasis in hens using combined in vivo and in vitro approaches. Our results showed that GnIH and its receptor, GPR147, are predominantly expressed in white follicles. Continuous GnIH injection significantly reduced the ovarian index and the number of prehierarchical follicles, concurrently suppressing Fshr and LHr expression in white follicles. Additionally, metabolomic analyses indicate changes in key glucose metabolism pathways, indicating a regulatory role of GnIH in glucose metabolism. To validate our metabolomics findings, the effects of GnIH on glucose homeostasis in ovarian white follicles and granulosa cells (GCs) were further investigated through in vivo and in vitro studies. The results demonstrated that GnIH enhanced glucose transport, glycolysis and glycogen synthesis, but concurrently induced insulin resistance, oxidative stress, and mitochondrial dysfunction, ultimately leading to reduced energy levels and apoptosis in ovarian tissues. In summary, our study reveals that GnIH contributes to ovarian dysfunction via glucose metabolism dysregulation in hens, suggesting its potential as a therapeutic target for metabolic disorder-associated ovarian impairment in chickens.

Pseudomonas aeruginosa is a major pathogen in canine pyoderma, with increasing antibiotic resistance necessitating the development of alternative therapies. This study aimed to isolate and characterize a lytic phage targeting multidrug-resistant P. aeruginosa and evaluate its therapeutic efficacy in a canine pyoderma model. The key methods include isolation of phage HJ01 from wastewater, identification of genomic and biological characteristics, and subcutaneous injection of HJ01 in a canine pyoderma model induced by P. aeruginosa. The host strain GDPA-01 exhibited multidrug resistance, with a 75

Clostridium perfringens (C. perfringens) type C exhibits strong pathogenicity, often leading to swine dysentery, severely affecting the economic efficiency of the pig farming industry. Bacteriophages as bacterial viruses have many natural advantages and are potent candidates for controlling bacterial infections. In this study, a lytic C. perfringens phage designed as vB_CpeP_15N3 was isolated with the host C. perfringens type C CVCC1155, and its potential for therapy was determined in vitro and in vivo. Despite the narrow host range, phage vB_CpeP_15N3 exhibited a large burst size of 102 PFU/cell following a short latent period of 10 min. In addition, phage vB_CpeP_15N3 remained stable at temperatures ranging from 4 to 50 degrees C and pH levels from 5 to 9 and had a strong antibacterial effect in vitro. Through whole-genome analysis, phage vB_CpeP_15N3 belongs to the family Guelinviridae, genus Brucesealvirus with no genes related to lysogeny and bacterial virulence or resistance. We further demonstrated that phage vB_CpeP_15N3 by oral administration for preventive purposes could significantly alleviate clinical symptoms and jejunal lesions of newborn piglets through the reduced colonization of C. perfringens type C in the jejunum and the level of CPB toxin in the content of jejunum in the newborn piglet model of CVCC1155 infection. In addition, phage vB_CpeP_15N3 by oral administration for preventive purposes could improve the diversity and abundance of the jejunum microbiota in newborn piglets. Moreover, the prevention by phage vB_CpeP_15N3 obtained more effective therapeutic results than phage and gentamicin treatments. Taken together, these findings suggested that phage vB_CpeP_15N3 is a promising alternative of antibiotics for preventing and controlling C. perfringens type C infection of newborn piglets.

Bacterial endometritis often causes significant economic losses in animal husbandry. Moreover, the problem of antibiotic resistance arising from traditional antibiotic treatments is becoming increasingly severe, making it urgent to develop new therapeutic agents that can reduce or replace antibiotics. In this study, Escherichia coli strain GXEC-K5 was isolated from sows with endometritis. The strain GXEC-K5 was identified using methods such as Gram staining, antimicrobial susceptibility testing, detection of virulence and drug resistance genes, and whole-genome sequencing. Additionally, an SD rat model of endometritis was successfully established. The experimental results showed that the use of the antibiotic enrofloxacin (ENR), phage (Phage EP01), and the combination of antibiotic and phage (ENR + EP01) all had certain therapeutic effects on metritis, among which the ENR + EP01 group showed the most significant therapeutic effect. This is specifically manifested by a decrease in the uterine index and bacterial load in uterine secretions, along with down-regulated mRNA levels of pro-inflammatory factors (IL-1β, IL-2, TNF-α and IFN-γ) and improvements in histopathological conditions. In addition, it alleviates endometritis by regulating the homeostasis of the flora, which is achieved by increasing the abundance of Delftia and Lactobacillus and decreasing the abundance of Faecalibaculum. In conclusion, this study provides a potential new strategy for the treatment of endometritis in the future and offers a new approach to addressing the issue of bacterial resistance encountered in the treatment of endometritis.

Edema disease (ED), a fatal disease in weaned piglets, is caused by Shiga toxin-producing Escherichia coli (STEC). The increasing emergence of antibiotic-resistant E. coli strains has necessitated the exploration of alternatives such as bacteriophage therapy. Using a porcine model, this study evaluated the prophylactic effect of bacteriophage P-GXEC-L2P5 administered by oral gavage against ED. The novel phage P-GXEC-L2P5 was isolated using a multidrug-resistant (MDR) STEC strain GXEC-STL2 as the host. P-GXEC-L2P5 was identified as a member of Caudoviricetes, Dhillonvirus, with an 88,607 base pair (bp) genome, and it possessed a short latent period (10 min), moderate pH stability (5–10), and appropriate thermal tolerance (4–60 ℃). Piglets pretreated with P-GXEC-L2P5 showed no apparent clinical signs (e.g., eyelid edema or neurological symptoms) after challenge with GXEC-STL2. B-scan ultrasound revealed no significant hydronephrosis. Necropsy showed only mild intestinal congestion, with no other gross pathological lesions noted. Histopathology demonstrated no significant differences in features compared with noninfected controls. Phage treatment significantly reduced fecal STEC shedding (P < 0.05) and significantly decreased Stx2e concentrations in serum, cerebral cortex, kidney, and small intestine (P < 0.01). The messenger RNA (mRNA) expression of Gb4 (Stx2e receptor) was significantly lower in these tissues (P < 0.05). Concurrently, vascular endothelial cells exhibited increased FITC-labeled wheat germ agglutinin (FITC-WGA) fluorescence intensity and increased mRNA expression of endothelial integrity factors (connexin43, vinculin, and zonula occludens-1; P < 0.05). In addition, phage treatment preserved jejunal microbiota diversity and abundance. In conclusion, P-GXEC-L2P5 effectively prevented STEC-induced ED by reducing STEC load and Stx2e levels, while mitigating increased vascular permeability.

INTRODUCTION:Since the discovery of gonadotropin-inhibitory hormone (GnIH), it has been found to play a critical role in reproduction in vertebrates. Recently, a regulatory role of GnIH in appetite and energy metabolism has emerged, although its precise physiological mechanisms remain unknown. METHODS:Thus, the present study evaluated the effects of a single or long-term intraperitoneal GnIH treatment on the food intake, weight, and glucolipid metabolism of chickens, as well as investigating the possible neuroendocrinology factors and mechanisms involved in GnIH-induced obesity and glucolipid metabolism disorder. RESULTS:Our results show that the intraperitoneal administration of GnIH to chickens resulted in a marked body mass increase, hyperlipidemia, hyperglycemia, and glucose intolerance. Subsequently, the results of metabolomics studies and the pharmacological inhibition of the 5-HT2C receptor revealed that blocking the 5-HT2C receptor reinforced the effects of GnIH on food intake, body weight, and blood glucose and lipid levels, resulting in even worse cases of GnIH-induced hyperglycemia, hyperlipidemia, and hepatic lipid deposition. This suggests that, via the 5-HT2C receptor, peripheral 5-HT may act as a negative feedback regulator to interplay with GnIH and jointly control energy balance homeostasis in chickens. DISCUSSION:Our present study provides evidence of cross-talk between GnIH and 5-HT in food intake and energy metabolism at the in vivo pharmacological level, and it proposes a molecular basis for these interactions, suggesting that functional interactions between GnIH and 5-HT may open new avenues for understanding the mechanism of the neuroendocrine network involved in appetite and energy metabolism, as well as providing a new therapeutic strategy to prevent obesity, diabetes, and metabolic disorders.

Salmonella Typhimurium (S. Typhimurium) contamination poses a significant challenge to breeder egg hatchability and chick health, necessitating the exploration of alternative disinfection methods. This study investigates the potential of phage vB_SPuM_SP02 (SP02) as a novel disinfectant for breeder eggs contaminated with S. Typhimurium SM022. Phage SP02 was isolated from poultry farm effluent and characterized for morphology, biological properties, and genome properties. Experimental groups of specific pathogen-free (SPF) eggs were treated with Salmonella and phage SP02, and efficacy was assessed through hatching rates, chick survival, weight, Salmonella load, immune organ indices, and intestinal flora. Phage treatment effectively eradicated Salmonella contamination on eggshells within 12 h, resulting in increased hatching and survival rates compared to controls. Furthermore, phage treatment mitigated weight loss and tissue Salmonella load in chicks without causing immune organ damage while reducing Salmonella spp. abundance in the intestinal tract. This study demonstrates the potential of phage SP02 as an eco-friendly and efficient disinfectant for S. Typhimurium-contaminated breeder eggs, offering promising prospects for practical application in poultry production.

Stress is known to disrupt the intestinal barrier and induce intestinal dysfunction. A critical role for gonadotropin inhibitory hormone (GnIH) in stress has emerged. However, whether GnIH mediates stress-induced intestinal dysfunction remains unknown. The present study explored this question through in vivo and in vitro experiments in hens. Our in vivo experiments showed that continuous intraperitoneal injection of GnIH not only significantly increased the concentration of stress hormones in serum, but also significantly elevated the mRNA expression of glucocorticoid receptor (GR) in the duodenum and jejunum. Moreover, morphological and molecular analyses revealed that GnIH disrupted the physical and chemical barriers of the intestine and dramatically increased inflammatory factor levels in the intestine and serum of hens. Interestingly, the microbiomics results showed that GnIH altered the structure and composition of the gut flora in the cecum, revealing an increased abundance of harmful intestinal bacteria such as Desulfovibrionaceae. Similar results were found in in vitro studies in which the GnIH-induced intestinal mucosal barrier was disrupted, and inflammation increased in jejunal explants, although no significant difference was found in the expression of GR between the control and GnIH groups. Our results demonstrated that GnIH not only directly damaged intestinal barriers and elevated intestinal inflammation but also mediated stress and microflora imbalance-induced intestinal function disorder, suggesting that GnIH is a potential therapeutic target for gut dysfunction, stress-induced intestinal function disorder, and inflammatory bowel disease in animals and humans.

Escherichia coli and Salmonella Typhimurium are the main pathogens of diarrhea in weaned piglets. The pre-vention of bacterial diarrhea in weaned piglets by phage is rarely reported. We conducted this study to evaluate the preventive effect of phages on mixed Escherichia coli and Salmonella Typhimurium infections in weaned piglets. A novel phage named NJ12 was isolated by using Salmonella Typhimurium SM022 as host bacteria and characterized by electron microscopy, genomic analysis and in vitro bacteriostatic activity. Phage NJ12 and a previously reported phage EP01 were microencapsulated with sodium alginate to make phage cocktail. Micro-encapsulated phage cocktail and PBS (Phosphate buffer solution) were used to piglets the phage and phage-free group through oral administration before bacterial infection 2 h, respectively. Piglets of the phage and phage-free group were consumed with feed contaminated with 6 mL (108CFU/mL) Escherichia coli O157:H7 GN07 (GXEC-N07) and 6 mL (108CFU/mL) SM022 every day for seven consecutive days. The results showed that piglets in the phage-free group had more severe diarrhea, larger decreased average weight gain and higher levels of neutro-phils compared with piglets in phage group. Meanwhile, piglets in the phage-free group had higher load of SM022 and GN07 in jejunal tissue and more severe intestinal damage compared with piglets in group phage in vivo. In addition, oral administration phage can significant decreased the relative abundance of Enterobacteri-aceae but hardly repaired the changes of diversity and composition of gut microbiota caused by the mixed infection of SM022 and GN07. This implies that phage used as a feed additive have a marvelous preventive effect on bacterial diarrhea during weaning of piglets.

PTD-FNK, a synthetic anti-apoptotic protein, has been shown to potently alleviate cellular injuries. However, the effects of PTD-FNK on oxidative defense in boar testicular Sertoli cells (SCs) against oxidative injury has not been explored. In this study, we show that exposure of SCs to 100 mg/L lipopolysaccharide (LPS) for 12 h leads to decreased survival rate, superoxide dismutase (SOD) activity, and increased malondialdehyde (MDA). Treatment with 0.01 nmol/L PTD-FNK for 4 h significantly enhanced the activity of SOD, catalase (CAT), glutathione peroxidase (GSH-Px), and total antioxidant capacity (T-AOC) in SCs. Concurrently, PTD-FNK treatment effectively reduced the production of reactive oxygen species (ROS) and the levels of 8-hydroxy-2′-deoxyguanosine (8-OHdG) in SCs. Moreover, using His pull-down and LC-MS techniques, we identified PTD-FNK-interacting proteins and confirmed that this protective effect may be mediated by the regulation of the Keap1-Nrf2 signaling pathway by PTD-FNK. Therefore, PTD-FNK alleviates LPS-induced oxidative stress via the Keap1/Nrf2 pathway, providing novel insights for the development of therapeutic agents targeting testicular oxidative damage.

[目的]分离有效裂解沙门氏菌的噬菌体,为探索新的沙门氏菌防控方法提供理论依据和参考.[方法]以鸡白痢沙门氏菌X-1014为宿主菌,通过双层琼脂平板法从污水中分离并纯化出噬菌体.采用噬菌斑与电子显微镜观察、宿主谱测定、生物学特性测试、体外抑菌试验及噬菌体的全基因组测序分析方法评估该噬菌体.[结果]分离纯化出1株能裂解沙门氏菌和大肠杆菌的裂解性噬菌体,命名为ZH5(GenBank登录号:OM864357.1).双层平板法结果显示,噬菌斑透亮且边缘清晰.电镜观察显示,噬菌体ZH5头部呈二十面体、头部直经约50 nm,尾部长度约20nm.宿主谱分析结果显示,噬菌体ZH5能裂解3株沙门氏菌和1株大肠杆菌.生物学特性结果显示,最佳感染复数为10,潜伏期和爆发期分别为20和60 min,裂解量约为139 PFU/cell;酸碱耐受范围为pH 4.0～10.0,且在温度为4～50 ℃的环境中能存活30 min.体外抑菌结果显示,当感染复数为10时,噬菌体ZH5对沙门氏菌X-1014和CVCC 1806抑制效果最佳.全基因组分析结果显示,该噬菌体全长为42 949 bp,GC含量为51.41％,其中已知功能编码序列(coding sequences,CDS)占比为52％.线性比对分析结果显示,噬菌体ZH5与大肠杆菌噬菌体Minorna相似性最高(相似性94.19％;覆盖率84％).系统发育进化树分析表明,噬菌体ZH5属于Drulisvirus属.[结论]本研究分离出1株能跨宿主裂解沙门氏菌和大肠杆菌的噬菌体,为进一步研究沙门氏菌抗菌剂提供了良好的材料.

During cold storage, boar spermatozoa undergo oxidative stress, which can impair sperm function and fertilizing capacity. The objective of the present study was to assess the effects of Schisandrin B (Sch B) in semen extenders on the quality of boar semen stored at hypothermia. Semen was collected from twelve Duroc boars and diluted in extenders supplemented with different concentrations of Sch B (0 μmol/L, 2.5 μmol/L, 5 μmol/L, 10 μmol/L, 20 μmol/L, and 40 μmol/L). Here, we demonstrated that 10 μmol/L Sch B provided the best effects on motility, plasma membrane integrity, acrosome integrity, sperm normality rate, average movement velocity, wobbility, mitochondrial membrane potential (MMP), and DNA integrity of sperm. The results of Sch B effects on antioxidant factors in boar sperm showed that Sch B significantly elevated the total antioxidant capacity (T-AOC) and markedly decreased the reactive oxygen species (ROS) and malondialdehyde (MDA) content of sperm. The expression of catalase (CAT) and superoxide dismutase (SOD) mRNA was increased, while the expression of glutathione peroxidase (GPx) mRNA demonstrated no change compared to non-treated boar sperm. Compared to the non-treated group, Sch B triggered a decrease in Ca2+/protein kinase A (PKA) and lactic acid content in boar sperm. Similarly, Sch B led to a statistically higher quantitative expression of AWN mRNA and a lower quantitative expression of porcine seminal protein I (PSP-I) and porcine seminal protein II (PSP-II) mRNA. In a further reverse validation test, no significant difference was observed in any of the parameters, including adhesion protein mRNA, calcium content, lactic acid content, PKA, and protein kinase G (PKG) activity after sperm capacitation. In conclusion, the current study indicates the efficient use of Sch B with a 10 μmol/L concentration in the treatment of boar sperm through its anti-apoptosis, antioxidative, and decapacitative mechanisms, suggesting that Sch B is a novel candidate for improving antioxidation and decapacitation factors in sperm in liquid at 4 °C.

【Objective】 It was planned to isolate a strain of phages with good bacteriostatic effect and wide adaptability for Escherichia coli,which provided a basis for the development of new Escherichia coli control methods.【Method】 Taking Escherichia coli H11 as the host bacteria, a strain of Escherichia coli phage was isolated and purified from sewage samples by double-layer agar plate method.The morphology of the phage was observed under electron microscope, and the titer, host spectrum, optimal multiplicity of infection（MOI）,one-step growth curve, pH stability and temperature sensitivity of the phage were determined.The whole phage genome was analyzed and sequenced, and the inhibitory effect of the phage on H11 in liquid medium was explored.【Result】 A lytic Escherichia coli phage was successfully isolated and named EP＿H11（accession number: OP688485）.The results of double-layer agar culture method showed that the phage EP＿H11 could form plaques with uniform size, transparent bright spots in the middle and halo around, and the phage cleavage titer could reach 10~9-10 10 PFU/mL.Electron microscopy showed that the phage EP＿H11 had a regular polyhedral head with a diameter of about 85 nm, a tail with a diameter of about 23 nm and a length of about 109 nm.Using Escherichia coli H11 as host bacteria, the optimal MOI of phage EP＿H11 was 0.1.The one-step growth curve showed that the incubation period was 40 min and the outbreak period was 80 min.The amount of cleavage was about 200 PFU/cell.The phage could survive for at least 2 h in the environment of pH 4.0-10.0,and could remain stable for 90 min at 10-60 ℃.Combined with transmission electron microscopy and whole genome analysis, the phage EP＿H11 belonged to the Caudovirales,Siphoviridae family, Myoviridae genus.The total length of the phage genome was 111 373 bp and the GC content was 44.49%.According to the results of phage linear comparison, Escherichia coli phage EP＿H11 and phage Escherichia phage vB＿EcoM＿IME392 had the highest homology.Phylogenetic tree analysis showed that the phage EP＿H11 and Escherichia phage vB＿EcoM＿IME392（Myoviridae genus） were located in the same branch, belonging to the order of Caudovirales and the Siphoviridae family.BLAST sequence analysis showed that there were 153 CDSs in genome of EP＿H11,28 of which were predicted to encode functional proteins.In vitro bacteriostasis results showed that within 8 h, EP＿H11 showed good bacteriostatic effect when MOI was 10. 【Conclusion】 In this study, a bacteriophage with strong lytic ability, wide adaptability and good bacteriostatic effect in vitro was isolated.The bacteriophage had the potential to be further developed as an antimicrobial agent for Escherichia coli.