Salmonella typhimurium (S. typhimurium) is a major foodborne pathogen with a significant public health impact. Meanwhile, Probiotics have recently gained attention for their safe and effective role in managing gastrointestinal disorders. This study evaluated the effects of a probiotic mixture (Lactobacillus acidophilus and Lactobacillus plantarum) on gut immunity and dysbiosis in mice infected with S. typhimurium. Mice were randomly assigned to four groups (n = 3 per group): (1) Healthy control (CNG); (2) Infected control (CPG); (3) Probiotics only (LAPG); (4) Probiotics + infected (LAPST). Probiotics-treated mice showed improved clinical outcomes and reduced fecal Salmonella load (p < 0.0001). Alpha and beta diversity analyses showed significant microbial composition differences between groups. Firmicutes were the most affected phyla, followed by Proteobacteria and Bacteroidetes. Infected mice (CPG) showed decreased Patescibacteria and Actinobacteria, while probiotic treatment (LAPST) restored their levels. Linear Discriminant Analysis Effect Size showed LAPST enriched beneficial genera (e.g., Lactobacillus murinus, Streptococcus, Candidatus Arthromitus) associated with gut homeostasis, bacteriocin production, metabolism, immunity, and intestinal barrier integrity. Real-time quantitative PCR results showed that probiotic supplementation downregulated pro-inflammatory and upregulated the anti-inflammatory cytokines (p ≤ 0.05). Additionally, it modulated genes involved in apoptosis, tight junctions, and oxidative stress. These findings provide mechanistic insight and may have translational relevance for managing Salmonella-induced gut disorders in livestock.

Influenza virus infections remain a serious threat to global public health, causing considerable morbidity and mortality each year. The growing interest in probiotics as natural antiviral agents provides new opportunities for developing alternative or adjunctive strategies against influenza infection. In this study, we investigated the anti-influenza virus activity of Lactobacillus Johnsonii (L. johnsonii) isolated from the bamboo rat (Rhizomys sinensis). The isolate was identified by 16S rRNA gene sequencing and biochemically characterized using the API 50 CHL kit. Antiviral activity was evaluated through both pre- and post-treatment approaches using broth suspensions, cell-free supernatants (CFS), bacterial pellets, and heat-killed preparations. Cytopathic effect (CPE) inhibition and MTT assays were employed to assess cell viability and antiviral efficacy. The pre-treated broth suspension exhibited the highest inhibitory activity, achieving 68% inhibition, while the post-treated suspension showed 61.3%. Similarly, CFS displayed 62.6% and 52.2% inhibition, bacterial pellets 56% and 47.9%, and heat-killed bacteria 47% and 46.3% inhibition in pre- and post-treatment assays, respectively. Notably, the pre-treatment approach consistently demonstrated stronger antiviral effects than post-treatment, suggesting a preventive mechanism of action. These results indicate that L. johnsonii exerts significant inhibitory effects against the influenza virus, potentially through the secretion of antiviral metabolites or modulation of host cellular responses. These findings provide preliminary evidence that L. johnsonii isolated from the bamboo rat possesses notable anti-influenza virus activity and warrants further investigation to elucidate its underlying mechanisms and potential applications.

Ulcerative colitis (UC) has become a global health issue. This study evaluated whether administering Lactiplantibacillus plantarum CGMCC9513 to dextran sulfate sodium (DSS)-induced colitis mice could alleviate colitis by modulating gut microbiota imbalance and activating the aryl hydrocarbon receptor (AhR) to enhance intestinal barrier function. The anti-inflammatory effect and AhR activation ability of L. plantarum CGMCC9513 were evaluated with lipopolysaccharide (LPS)-induced cell inflammation model; 25 male BALB/c mice were divided into blank group (CNG), model group (DSS), L. plantarum CGMCC9513-treated group (LPDT), and L. plantarum CGMCC9513 control group (LP). The mice were pre-administered L. plantarum CGMCC9513 for 14 days and continued to receive it during DSS induction. Symptoms during induction, goblet cell count, expression of MUC2 and Occludin proteins, and changes in gut microbiota were observed. Subsequently, the expression of cytokines interleukin-10 (IL-10), tumor necrosis factor (TNF-α), interleukin-1β (IL-1β) and AhR activation status was determined. The study found that L. plantarum CGMCC9513 could alleviate cell inflammation induced by LPS and activate AhR in vitro. For colitis mice, it could reduce colonic mucosal damage and enhance intestinal barrier function. Regarding gut microbiota changes, L. plantarum CGMCC9513 mainly downregulated Bacteroides, Blautia, Escherichia-Shigella, and Lachnospiraceae_ NK4A136_group and upregulated Firmicutes, Lactobacillus. It reduces the risk of bacterial translocation and increases beneficial gut bacteria. L. plantarum CGMCC9513 reduced the expression of pro-inflammatory cytokines TNF-α and IL-1β while increasing the expression of anti-inflammatory cytokine IL-10. Meanwhile, increased expression of AhR and Cytochrome P450 1A1 (CYP1A1) proteins indicated AhR activation by L. plantarum CGMCC9513. In conclusion, L. plantarum CGMCC9513 can synergistically enhance intestinal barrier alleviation in colitis mice by modulating gut microbiota imbalance and activating AhR.

Salmonella enterica serovar Typhimurium (S. Typhimurium), a foodborne pathogen that poses significant public health risks to humans and animals, presents a formidable challenge due to its antibiotic resistance. This study explores the potential of Lactobacillus acidophilus (L. acidophilus 1.3251) probiotics as an alternative strategy to combat antibiotic resistance associated with S. Typhimurium infection. In this investigation, twenty-four BALB/c mice were assigned to four groups: a non-infected, non-treated group (CNG); an infected, non-treated group (CPG); a group fed with L. acidophilus but not infected (LAG); and a group fed with L. acidophilus and challenged with Salmonella (LAST). The results revealed a reduction in Salmonella levels in the feces of mice, along with restored weight and improved overall health in the LAST compared to the CPG. The feeding of L. acidophilus was found to downregulate pro-inflammatory cytokine mRNA induced by Salmonella while upregulating anti-inflammatory cytokines. Additionally, it influenced the expression of mRNA transcript, encoding tight junction protein, oxidative stress-induced enzymes, and apoptosis-related mRNA expression. Furthermore, the LEfSe analysis demonstrated a significant shift in the abundance of critical commensal genera in the LAST, essential for maintaining gut homeostasis, metabolic reactions, anti-inflammatory responses, and butyrate production. Transcriptomic analysis revealed 2173 upregulated and 506 downregulated differentially expressed genes (DEGs) in the LAST vs. the CPG. Functional analysis of these DEGs highlighted their involvement in immunity, metabolism, and cellular development. Kyoto Encyclopedia of Genes and Genome (KEGG) pathway analysis indicated their role in tumor necrosis factor (TNF), mitogen-activated protein kinase (MAPK), chemokine, Forkhead box O (FOXO), and transforming growth factor (TGF-β) signaling pathway. Moreover, the fecal metabolomic analysis identified 929 differential metabolites, with enrichment observed in valine, leucine, isoleucine, taurine, glycine, and other metabolites. These findings suggest that supplementation with L. acidophilus promotes the growth of beneficial commensal genera while mitigating Salmonella-induced intestinal disruption by modulating immunity, gut homeostasis, gut barrier integrity, and metabolism.

Salmonella typhimurium (S. typhimurium), a prevalent cause of foodborne infection, induces significant changes in the host transcriptome and metabolome. The lack of therapeutics with minimal or no side effects prompts the scientific community to explore alternative therapies. This study investigates the therapeutic potential of a probiotic mixture comprising Lactobacillus acidophilus (L. acidophilus 1.3251) and Lactobacillus plantarum (L. plantarum 9513) against S. typhimurium, utilizing transcriptome and metabolomic analyses, a novel approach that has not been previously documented. Twenty-four SPF-BALB/c mice were divided into four groups: control negative group (CNG); positive control group (CPG); probiotic-supplemented non-challenged group (LAPG); and probiotic-supplemented Salmonella-challenged group (LAPST). An RNA-sequencing analysis of small intestinal (ileum) tissue revealed 2907 upregulated and 394 downregulated DEGs in the LAPST vs. CPG group. A functional analysis of DEGs highlighted their significantly altered gene ontology (GO) terms related to metabolism, gut integrity, cellular development, and immunity (p ≤ 0.05). The KEGG analysis showed that differentially expressed genes (DEGs) in the LAPST group were primarily involved in pathways related to gut integrity, immunity, and metabolism, such as MAPK, PI3K-Akt, AMPK, the tryptophan metabolism, the glycine, serine, and threonine metabolism, ECM–receptor interaction, and others. Additionally, the fecal metabolic analysis identified 1215 upregulated and 305 downregulated metabolites in the LAPST vs. CPG group, implying their involvement in KEGG pathways including bile secretion, propanoate metabolism, arginine and proline metabolism, amino acid biosynthesis, and protein digestion and absorption, which are vital for maintaining barrier integrity, immunity, and metabolism. In conclusion, these findings suggest that the administration of a probiotic mixture improves immunity, maintains gut homeostasis and barrier integrity, and enhances metabolism in Salmonella infection.

A new naphtho-γ-pyrone dimer, asperosperma A, and a new methyl nicotinate derivative, asperosperma B, with 12 known compounds were isolated from the endophytic fungus Aspergillus niger from the stem of Camellia flavida. Their structure was elucidated by NMR, ECD spectrum, and HR-ESI-MS data. Asperosperma A exhibited a highly cytotoxicity against H460 and 4T1 cancer cells with the IC50 values were 0.37 ± 0.06 and 2.04 ± 0.79 μM, respectively. Moreover, it showed a highly sensitive against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and methicillin-resistant S. aureus.

This study introduces an advanced electrochemical biosensor that utilizes MoS 2 @CNT as an electrode material combined with a specific DNA probe to detect Salmonella Typhi rapidly and accurately. The sensor offers a broad detection range from 1.0 x 10- 6 to 1.0 x 10- 18 molL- 1 and boasts an exceptionally low limit of detection (LOD) of 1.0 x 10- 20 molL- 1 for the target bacterium. It demonstrates a detection range from 1.0 x 10 4 to 1.0 x 10 11 CFUml- 1 in real samples, with a corresponding LOD of 1.0 x 10 4 CFUml- 1 . Rigorous testing against base mismatches and various bacterial strains confirms its specificity, ensuring reliable performance. Validated in real samples, the biosensor can accurately identify Salmonella Typhi in water and milk, achieving recoveries ranging from 92.95 % to 99.58 %. The exceptional performance of the biosensor is attributed to the MoS 2 @CNT electrode material and the specific DNA recognition probe, which enhance electron transfer and reduce steric impedance. These improvements contribute to the sensor ' s enhanced sensitivity and specificity, making it a significant advancement in public health safety by providing a rapid and accurate tool for detecting Salmonella Typhi in food samples.

Context Piglets encounter numerous challenges post-birth, and positive maternal influences can significantly aid their survival. Aims This study aimed to investigate the potential impact of dietary fiber (DF) consumption during pregnancy on the establishment of colonic flora and immunity in offspring. Methods Sixty-eight multiparous sows were randomly assigned to either a control diet lacking fiber sources or a diet supplemented with a fiber mixture. The study evaluated the developmental status, intestinal microecology, and immune indices, including the expression of Toll-like receptors and nuclear factor kappa-B, tumor necrosis factor alpha, interleukins 6 and 10, and interferon gamma, as well as the concentrations of complement components 3 and 4, and immunoglobulins G and M in the offspring. Key results The findings revealed a significant reduction in Toll-like receptor 4 and nuclear factor kappa-B messenger RNA levels in the colon and tumor necrosis factor alpha levels in the serum of 21-day-weaned piglets from the fiber group, indicating a decrease in inflammation. Moreover, there was a notable increase in the abundance of Roseburia and Lactobacillus in the colons of weaned piglets from the fiber-supplemented group, whereas Odoribacter showed a substantial decrease. This indicates that sows transfer beneficial microorganisms to their piglets, and fiber supplementation further enhances these positive microbial changes. Conclusion This study highlights the positive impact on the microbiota profile and immunity of piglets of fiber supplementation in sow diets during pregnancy, using a 3% purified fiber mixture. These findings hold implications for the enhanced development of weaned piglets, providing valuable theoretical support.

H1N1 influenza is highly contagious and can cause zoonotic respiratory disease. Thus, early detection is essential to prevent and control its rapid spread in the population. Given the limitations of traditional detection methods in clinical laboratories, an electrochemical biosensor modified with TAPT-TP COFs/MWCNT nanomaterial (TAPT: 4,4 ',4 ''-(1,3,5-Triazine-2,4,6-trial) trianiline; TP: 1,3,5-Triformylphloroglucinol; MWCNTs: Multiwalled carbon nanotubes), dual-probe-specific recognizer and signal amplifier was reported, which was capable of quantifying H1N1 virus complementary DNA (cDNA) from 10 fM to 1 nM (limit of detection, LOD = 1.01 fM) with distinguished selectivity and reproducibility. Furthermore, the portable device achieved a detection range of 1 fM to 1 pM and LOD of 0.17 fM, and the accuracy was confirmed by spiked recovery experiments (recovery: 98.01-101.24%). The applicability of the portable biosensing device was verified by quantifying the concentration of H1N1 virus in the nasal turbinates and lung tissue of mice, the results of which were compared with droplet PCR (ddPCR) to validate its reliability (P > 0.05) and confirm its potential application in influenza surveillance. Thus, the above biosensor can help doctors or other professionals obtain rapid and accurate monitoring results and is expected to realize the on-site diagnosis of the H1N1 influenza virus for early intervention and epidemic management.

Influenza A virus (IAV) can cause influenza, a highly infectious zoonotic respiratory disease, and early detection is essential to prevent and control its rapid spread in the population. Given the limitations of traditional detection methods in clinical laboratories, we report a large surface TPB-DVA COFs (TPB: 1,3,5-Tris(4-aminophenyl) benzene, DVA: 1,4-Benzenedicarboxaldehyd, COFs: Covalent organic frameworks) nanomaterial modifled elec-trochemical DNA biosensor, which has dual-probe speciflc recognition and signal ampliflcation. The biosensor enables quantitative detection of influenza A viruses' complementary DNA (cDNA) from 10 fM to 1 x 103 nM (LOD = 5.42 fM) with good speciflcity and high selectivity. The reliability of the biosensor and portable device was verifled by comparing the virus concentrations in animal tissues with those measured by digital droplet PCR (ddPCR) (P > 0.05). Moreover, the potential for influenza surveillance in this work was demonstrated by detecting the tissue samples from mice at different stages of infection. In summary, the good performance of this electrochemical DNA biosensor we proposed suggested it has the potential to be a rapid detection device for the influenza A virus, which could assist doctors or other professionals in obtaining rapid and accurate results for outbreak investigation and disease diagnosis.

MiRNA-155 is a typical biomarker for breast cancer. Since its low concentration in the physiological environment and the limitations of conventional miRNA detection methods like Northern imprinting and RT-qPCR, conve-nient, real-time, and rapid detection methods are urgently needed. In this work, an electrochemical biosensor was constructed based on the flower-like MoSe2@1T-MoS2 heterojunction electrode material and specific RNA recognition probes, which can realize the rapid determination of miRNA-155 content with a wide detection range from 1 fM to 1 nM and a limit of detection (LOD) as low as 0.34 fM. Furthermore, the contents of miRNA-155 in blood samples of tumor-bearing mice and normal mice were measured as 724.93 pM and 21.42 pM, respectively by this biosensor, demonstrating its strong identification ability and miRNA-155 can be regarded as an ideal diagnostic marker. On this basis, a portable sensor platform was designed for on-site detection simulation and showed good recovery efficiency from 95.80% to 98.69%. Meanwhile, compared with the standard detection method RT-qPCR, the accuracy and reliability of the biosensor were verified, indicating that the biosensor has the potential to provide point-of-care testing (POCT) for the early diagnosis of breast cancer.

958 lung tissue samples of swine influenza were collected in Guangxi from 2013 to 2014 to further study the pathogenic mechanism and prevention and control technology of influenza virus, and influenza virus isolation and biological characteristics analysis of Eurasian avian influenza (ER-H1N1) were performed. The positive rate of the 14 strains of ER-H1N1 swine influenza virus isolated was 1.46%, with 8 gene pieces all from avian sublineages, followed by recombinant Pdm/09 H1N1 fragments. Although their HA cleavage site is PSIQSR↓GLF or GIF, which has typical low-pathogenicity characteristics, the isolated virus strain grows well on the cell, and after the BALB/c mouse challenge experiment, the evidence of the isolated strain multiplying in the respiratory tract of mice is obvious, and the mice lose weight quickly, all die within a week and are accompanied by severe systemic infection. Based on changes in the amino acid residues of the A/swine/Guangxi/6/2013 (No.6) strain, it is thought that the NA protein E119G mutation is the main site where highly dangerous changes happen. D N mutations in the PB2 strains G2, g14, g21, g30, S2, 32, 7, and 8 show that these strains are gradually adapting to human sources. According to the traits of strains 30, G2, G14, and G21, NP develops 375 , which boosts pathogenicity. In summary, the ER-H1N1 subtype influenza virus is widespread in the Guangxi swine herd, and it is pathogenic to mice, with the trend of genomes derived from Pdm/09 H1N1 fragments increasing.

ABSTRACTDuring an investigation in October 2018, two people with diarrhoea, mild abdominal pain, and mild arthralgia symptoms in Guangxi, China, were identified as infected by H9N2 avian influenza virus (AIV). Four H9N2 AIVs were isolated from one of two patients, a pet cat, and a dead chicken (two respective isolates from its lung and kidney tissues) bred by the patients at a backyard farm. Epidemiological investigation indicated that the newly bought chicken died first, and clinical syndromes appeared subsequently in the two owners and one cat. Furthermore, the two individuals possessed high H9N2-specific hemagglutination inhibition and microneutralization antibodies. Shared nucleotide sequence identity (99.9% – 100%) for all genes was detected in the four H9N2 isolates, and hemagglutinin (HA) T138A located on the receptor binding domain (RBD), resulted from nucleotide polymorphisms that were exclusively found in the isolate from the female patient. Moreover, HA K137N on the RBD was found in isolates from these three host species. Importantly, these four H9N2 isolates presented an exclusive binding preference for the human-type receptor (α2-6-SA), and could replicate and cause pathological changes in mice. Phylogenetic analyses showed that these four isolates clustered together and belonged to clade C1.2, lineage Y280. In addition, H9N2 viruses of human origin are genetically divergent and interspersed with the widespread poultry-origin H9N2 AIVs. All these results indicate a high risk of H9N2 AIVs in public health, and effective prevention and control measures against H9N2 AIVs should be considered and performed for both animal and human health.

采集广西25个猪场的病料,对猪流行性腹泻病毒(PEDV)阳性组织样品进行全S基因扩增.将41株全S基因进行序列比对及遗传进化分析,41株PEDV的S基因之间核苷酸同源性为94.8％～100％,与参考毒株核苷酸同源性为89.3％～99.4％.S基因进化树图谱显示,广西当前流行的PEDV可分为2个谱系.Attenuated-DR13、CV777和该研究中的 CHGXLC055-92013、CHGXLC055-52013、CHGXGP035-72013和 CHGXGP035-82013为 Cluster1;Cluster3包括该研究另外37株毒株、韩国株 Spk1、HuN和日本株NK等参考毒株.表明广西大部分毒株S基因与欧洲株CV777、LZC等国内早期毒株存在较大的差异,进化树亲缘关系比较远;在抗原表位区域存在较大变异,当前的CV777疫苗株在防控PEDV入侵时可能不会产生良好的免疫保护效果.

目的 利用定点突变技术突变Pdm/09 H1N1流感病毒的NA基因119位点并拯救,研究其生物特性.方法 利用重叠PCR的方法进行定点突变,再应用反向遗传学体系中的pBD-NA质粒后在293T细胞中转染拯救流感病毒,通过血凝试验和RT-PCR方法鉴定病毒拯救结果,通过细胞学和攻毒试验研究该位点变异的生物学意义.结果 定点突变测序结果显示,突变的pBD-NA质粒核苷酸第336位由A突变为G,使氨基酸位点发生E(核苷酸:GAA)到G(核苷酸:GGA)的变化,而其他位置的氨基酸均未发生改变.拯救的病毒转染后的细胞悬液接种MDCK细胞连续传代3代后突变毒株(rMT)血凝效价为27,亲本毒株(rWT)为26.神经氨酸酶的二级结构预测结果显示,rMT与rWT相比,Alpha Helix分值明显下降,均值同比下降约为10.62％,经突变后的rMT Alpha Helix结构分值表现为下降趋势.用rWT和rMT病毒攻毒BABL/c小鼠后第3天的小鼠肺组织、鼻甲骨、脾和肾的病毒滴度,rMT攻毒组均比rWT攻毒组高,鼻甲组织与肺脏中的病毒滴度相比差异不显著,脾和肾的差异显著.结论 NA119位点的定点突变对病毒的复制能力没有明显影响,突变株对BABL/c小鼠的致病力有一定增强,临床症状明显,神经氨酸酶活性下降.

[目的]对黄皮与山黄皮共5个品种的不同部位进行黄酮、多酚含量及抗氧化活性比较,为黄皮属植物资源的开发利用提供理论依据.[方法]以香蜜黄皮、鸡心黄皮、龙州山黄皮1号、YYS-002和龙州单核山黄皮为试验材料,对其叶、茎、果核及果皮部位采用NaNO2-AlCl3-NaOH测定总黄酮含量、Folin-Ciocalteu法测定总多酚含量,再以1,1-二苯基-2-三硝基苯肼自由基(DPPH·)、羟自由基(·OH)和2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐自由基(ABTS+)清除率评价其抗氧化活性,并采用Pearson相关分析法分析其总黄酮、总多酚含量与各项抗氧化活性指标的相关性.[结果]5个品种中叶、茎、果核和果皮各部位的总黄酮含量介于0.34～86.23 mg/g,总多酚含量介于0.54～43.33 mg/g,其中黄皮品种的含量普遍低于山黄皮品种,不同部位的含量排序整体表现为果皮>叶>茎>果核.综合对比,龙州单核山黄皮的总黄酮、总多酚含量均高于其他品种,果皮和叶部位的总黄酮和总多酚含量显著高于其他部位(P<0.05).抗氧化活性结果表明,龙州单核山黄皮果皮的DPPH·、·OH和ABTS+清除率均最高,分别为96.01％、92.23％和76.96％,分别与0.03、0.03和0.01 mg/g抗坏血酸(Vc)清除率相当,对应半清除率浓度(IC50)分别为0.33、0.45和0.52 mg/mL;不同部位的各抗氧化活性强弱也整体表现为果皮>叶>茎>果核.相关分析结果表明,总黄酮、总多酚含量与各抗氧化活性指标均呈极显著正相关(P<0.01).[结论]龙州单核山黄皮果皮抗氧化能力最高,可作为天然抗氧化剂资源加以深入研究开发.黄酮和多酚类物质均为黄皮与山黄皮发挥抗氧化活性的相关物质基础,且多酚对抗氧化活性影响较大.

目的 对广西犬只尤其是宠物犬中携带H9N2亚型流感病毒进行全基因组序列特征分析以及小鼠的致病性研究,为流感病毒疫情的防控提供科学依据.方法 采用RT-PCR的方法扩增、测序全基因组,DNAStar和MEGA6.0软件分析氨基酸同源性和进化树,通过小鼠感染实验探究其致病性.结果 13株H9N2毒株8个基因节段来源于5个不同谱系的毒株,属于新基因型,氨基酸同源性与广西分离株A/equine/Guangxi/3/2011≥99.0％,6个内部基因与2013年自人流感病毒分离株H7N9亲缘关系密切.毒株HA的裂解位点均为RSSR↓ GLF,表明低致病力.氨基酸位点HA226、NA119、NP375和PB2的701位等有变化,其中HA226位为亮氨酸L,具有与人SAα2,6-Gal结合的特性.BALB/c小鼠感染健康犬只中分离的H9N2病毒未在体内复制,而源自感冒犬只的毒株Ca/GX/8和Ca/GX/10能够在体内复制,临床症状明显但不致死.病毒经小鼠体内传代后致病力增强,推测是PB2的611位和PA623位氨基酸改变导致.结论 从广西各地犬只中获得的13株H9N2亚型流感病毒株经分析发现虽源于禽源,但具备和人源受体特异性结合的能力,且内部基因遗传进化关系复杂,对哺乳动物及人类存在较大威胁,亟需加强防控.

目的 对一株分离自广西兴安的猪源A(2009/H1N1)流感病毒进行遗传演化分析及致病性研究,为流感疫情防控提供科学依据.方法 通过SPF鸡胚进行流感病毒分离,对8个基因进行RT-PCR扩增、测序及进化分析;以6周龄雌性BALB/c小鼠为感染模型进行病毒滴定,分析临床数据评估病毒致病性.结果 分离的甲型H1N1病毒株A/swine/Guangxi/18/2013(H1N1) HA、NS和NP基因属于古典型H1N1,NA和M基因源于类禽型H1N1,PA和PB2基因归属禽源,PB1基因来自人源H3N2.HA裂解位点序列为PSIQSR↓ GLF,具有低致病性特征.以50μl 106 TCID50感染小鼠后其体重发生明显变化,最高体重平均变化率为86.98％,死亡率为12.5％;感染第3d测定肺、鼻甲病毒滴度(Log10 TCID50/ml)分别为5.25±0.28和3.89±0.47.结论 A/swine/Guangxi/18/2013(H1N1)为2009/H1N1流感病毒,能感染小鼠而造成体重下降并产生明显的临床症状.该病毒能在小鼠肺与鼻甲中进行复制,具有低致病性特征.

[目的]明确广西猪源H9N2亚型流感病毒的遗传特征及分子生物学特性(抗原性、耐药性和致病性),为广西猪源H9N2亚型流感病毒的防控提供科学依据.[方法]以分离自广西百色地区的2株猪源H9N2亚型流感病毒(SW/GX/P2/2011株和SW/GX/P3/2011株)为研究对象,运用RT-PCR扩增其全基因组的8个基因片段(HA、NA、NP、M、NS、PB1、PB2和PA基因),经克隆测序后进行核苷酸序列及氨基酸位点分析.[结果]2株广西猪源H9N2亚型流感病毒的核苷酸序列开放阅读框(ORF)分别是PB2:2280 bp、PB1:2274 bp、PA:2151 bp、HA:1683 bp、NP:1497 bp、NA:1410 bp、M:982 bp和NS:838 bp.2株广西猪源H9N2亚型流感病毒全基因组仅M基因核苷酸序列与猪源H9N2亚型流感病毒的相似性较高,而HA、NA、NP、NS、PA、PB2和PB1基因核苷酸序列均与禽源H9N2亚型流感病毒的相似性较高,在基因型分类上属于G57基因型,为我国广泛流行的H9N2亚型基因型.2株广西猪源H9N2亚型流感病毒的HA蛋白发生R180Q、T213A、D216E、M224L、N285S和V287T突变,NA蛋白抗原决定簇S331V、W403S和Q431K也发生突变;NA蛋白在N2亚型的耐药性关键位点119E、151D、292R、276E和294N位点未发生突变,但在NA蛋白抗原区存在S331V、K367E和Q432K突变,且M2氨基酸位点发生S31N突变.2株广西猪源H9N2亚型流感病毒HA蛋白连接HA1和HA2的氨基酸均为RSSR↓GLF;HA蛋白存在1个因P315S突变而新增的潜在糖基化位点(NCS);NA蛋白未缺失NA潜在糖基化位点,也未出现NA蛋白颈部杆状结构63～65 aa缺失现象,在NA潜在糖基化位点中69、86、146、200和234 aa处非常保守,但发生W402S突变.[结论]从广西百色分离获得的2株猪源H9N2亚型流感病毒(SW/GX/P2/2011株和SW/GX/P3/2011株)虽为低致病力毒株,但在流感病毒基因重组过程中发挥重要作用,且其致病性有增强趋势,已对金刚烷胺类药物产生耐药性.因此,应加强广西地区哺乳动物H9N2亚型流感病毒的监控,并警惕其跨种间传播.