生物安全三级实验室生物安全风险点的识别与控制?

BSL-3实验室须经国家生物安全认可和严格的实验活动审批才能开展相应活动,是国家(地区)开展高致病性病原微生物实验活动的重要技术支撑平台。实验室生物安全风险点易发生在样本及菌毒种的接收、传递和保存,动物实验,污水以及固体废弃物处理等环节,而实验室的意外事件(电力故障、火灾、积水等)与生物安保漏洞也会造成重大的生物安全事故。提示应准确地识别风险并通过人员日常监管、标准操作规程、两级屏障设施和个人防护装备等系列措施对生物安全风险点予以严格控制。     

基于近红外光谱的北京市全株玉米原料康奈尔净碳水化合物-蛋白质体系组分分析与预测

本试验旨在基于康奈尔净碳水化合物-蛋白质体系(CNCPS)建立北京市全株玉米原料营养成分数据库,并利用近红外光谱(NIRS)方法建立其营养价值预测模型。试验采集北京市18个牧场89份全株玉米原料样品,测定其营养成分,利用CNCPS 6.5计算各样品碳水化合物(CHO)和蛋白质组成。定标集和验证集根据4∶1的配比关系,分别选用71份和18份全株玉米原料样品作为定标集和验证集评价NIRS模型。结果显示:1) NIRS分析技术对全株玉米原料常规营养成分、CNCPS中蛋白质组成和CHO组成均具有较好的预测能力,且精确度较高。2)干物质(DM)、粗灰分(Ash)、粗蛋白质(CP)、粗脂肪(EE)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)、酸性洗涤木质素(ADL)、淀粉(Starch)、中性洗涤不溶蛋白质(NDIP)、酸性洗涤不溶蛋白质(ADIP)、可溶性蛋白质(SP)、CHO、非纤维性碳水化合物(NFC)、可溶性纤维(CB2)、可消化纤维(CB3)、不消化纤维(CC)、可溶性真蛋白质(PA2)、难溶性真蛋白质(PB1)、纤维结合蛋白质(PB2)和非降解蛋白质(PC)的定标决定系数(1-VR)均>0.80,验证决定系数(RSQv)均≥0.84,这些模型均可用于日常快速检测分析。DM、Ash、EE、NDF、ADF、ADL、Starch、NDIP、CHO、NFC、CB2、CB3、PC和PB1的NIRS模型参数均采用二阶导数处理,CP、SP、ADIP、CC、PA2和PB2的NIRS模型参数均采用标准正态变量+二阶导数处理。综上所述,本研究提供了全株玉米原料的基础化学分析数据,并通过NIRS分析技术建立了主要营养成分的快速预测模型,有利于养殖场青贮前对全株玉米原料质量的快速评估。     

Effects of Antidesma thwaitesianum Muell. Arg. pomace as a source of plant secondary compounds on digestibility,rumen environment,hematology, and milk production in dairy cows

Mao pomace meal (MPM) contains condensed tannins and saponins at 92 and 98 g/kg, respectively, and these substances can be used to manipulate ruminal fermentation in ruminant. Four multiparous lactating Holstein cows with 45 ± 5 days in milk were randomly assigned according to a 4 × 4 Latin square design to receive four different levels of MPM supplementation at 0, 100, 200, and 300 g/head/day, respectively. Cows were fed with concentrate diets at 1:1.5 of concentrate to milk yield ratio and urea‐treated (3%) rice straw was fed ad libitum. The results revealed that feed intake, nutrient digestibility, blood urea nitrogen, and hematological parameters were not affected by MPM supplementation (p > 0.05). However, ruminal pH and propionate were increased quadratically (p < 0.05) in cows receiving MPM whereas acetate, acetate to propionate ratio and estimate methane production were decreased (p < 0.05). Supplementation of MPM linearly decreased ruminal ammonia nitrogen and protozoal population at 4 hr postfeeding (p < 0.05). Milk production and milk composition were similar among treatments (p > 0.05). In conclusion, supplementation of MPM at 200 g/head/day could modify ruminal fermentation and reduce methane production without adverse effect on feed intake, digestibility, hematological parameters, and milk production in dairy cows.     

中、意蜂Atg12基因克隆表达及生物信息学分析

试验旨在探究自噬相关基因Atg12(autophagy-related 12 gene)在中华蜜蜂(中蜂)、意大利蜜蜂(意蜂)中的表达差异,为探讨中蜂抗螨分子机理提供参考。参照GenBank中东方蜜蜂Atg12基因序列(登录号:XM_017048509.1)设计引物,扩增中、意蜂头部组织Atg12基因,并对其进行克隆、测序、原核表达及其氨基酸序列和蛋白结构分析,同时采用实时荧光定量PCR技术分析该基因在中、意蜂头部组织中的表达差异。结果显示,本试验成功扩增出大小为450 bp的目的片段,并表达出大小约42 ku重组蛋白;遗传进化树分析表明,在Atg12基因进化过程中,中蜂(Apis cerana cerana)、意蜂(Apis mellifera)、大蜜蜂(Apis dorsata)和小蜜蜂(Apis florea)亲缘关系较近;重组蛋白生物信息学分析显示,该蛋白的二级结构中共含有6个多肽结合位点、6个β-折叠和4个α-螺旋,分子质量约为16.13 ku,等电点为6.73;实时荧光定量PCR结果显示,Atg12基因在中蜂头部组织中表达极显著高于意蜂(P<0.01)。本试验结果为后续深入研究Atg12基因在中蜂抗螨上的作用机制提供了参考。     

鄱阳湖黑鹳越冬种群数量与空间分布

本研究于2003—2016年采用样线法对鄱阳湖越冬黑鹳种群数量和空间分布进行了同步调查,调查范围包括鄱阳湖周边三市13县72个子湖泊及周边草洲。结果表明:鄱阳湖黑鹳越冬种群数量年平均值为(35. 5±38. 5)只,其中2005年数量最多,为145只。鄱阳湖黑鹳越冬种群数量年际波动较大。共在15个子湖泊记录到黑鹳,主要分布区域为鄱阳县和鄱阳湖国家级自然保护区,其中鄱阳县湖区黑鹳记录总数量为371只,占鄱阳湖区历年黑鹳分布数量总和的74. 6%。鄱阳湖黑鹳越冬种群呈聚集型分布,只有17. 3%的黑鹳分布在鄱阳湖区主要的候鸟保护区内。本研究表明鄱阳湖越冬黑鹳主要分布于鄱阳湖重要的候鸟保护区范围之外,为有效地保护鄱阳湖黑鹳越冬种群,建议加强黑鹳种群监测,建立健全黑鹳种群就地保护体系。     

Plasma haptoglobin and immunoglobulins as diagnostic indicators of deoxynivalenol intoxication

This study aimed to discover potential biomarkers for dioxynivalenol (DON) intoxication. B6C3F1 male mice were orally exposed to 0.83, 2.5 and 7.5 mg/kg body weight (bw) DON for 8 days and the differential protein expressions in their blood plasma were determined by SELDI - Time-of-Flight/Mass Spectrometry (TOF/MS) and the immunoglobulins (Igs) G, A, M and E in the serum were investigated. 11.7 kDa protein was significantly highly expressed according to DON administration and this protein was purified by employing a methyl ceramic HyperD F column with using optimization buffer for adsorption and desorption. The purified protein was identified as a haptoglobin precursor by peptide mapping with using LC/Q-TOF/MS and MALDI-TOF/MS and this was confirmed by western blotting and ELISA. IgG and IgM in serum were decreased in a dose-dependent manner and IgA was decreased at 7.5 mg/kg bw DON administration, but the IgE level was not changed. To compare the expressions of haptoglobin and the Igs patterns between aflatoxin B1 (AFB1), zearalenone (ZEA) and DON intoxications, rats were orally administered with AFB1 1.0, ZEA 240 and DON 7.5 mg/kg bw for 8 days. Haptoglobin was increased only at DON 7.5 mg/kg bw, while it was slightly decreased at ZEA 240 mg/kg bw and it was not detected at all at AFB1 1.0 mg/kg bw. IgG and IgA were decreased by DON, but IgG, IgA, IgM and IgE were all increased by AFB1. No changes were observed by ZEA administration. These results show that plasma haptoglobin could be a diagnostic biomarker for DON intoxication when this is combined with examining the serum Igs.     

丙酮酸钙对山羊瘤胃挥发性脂肪酸浓度动态变化的影响

以8只装有永久性瘤胃瘘管的成年徐淮山羊为试验动物,采用自身对照设计,研究丙酮酸钙对山羊瘤胃内挥发性脂肪酸浓度动态变化的影响.结果表明:与对照组相比,添喂丙酮酸钙后,在0～8h内,对pH值无显著影响.4h时,总挥发性脂肪酸(TVFA)浓度升高25%(P<0.01);丙酸浓度升高60%(P<0.01).0～8h内,丙酸比例均高于对照组(17%～30%);乙丙比均低于对照组(20%～29%).说明在山羊日粮中添加一定量丙酮酸钙,可在不影响pH值的情况下,提高丙酸比例,降低乙丙比,改变瘤胃发酵类型.     

沙冬青种子总黄酮活性成分分析及对小鼠免疫功能的影响

本研究旨在通过高效液相色谱-质谱联用（LC-MS）和高效液相色谱（HPLC）技术对沙冬青种子总黄酮主要活性成分进行分析及含量测定,并探索沙冬青种子总黄酮对小鼠免疫功能的影响。采用LC-MS分析沙冬青种子总黄酮主要活性成分,在HPLC优化条件下用标准品对主要活性成分的含量进行测定;采用MTT法和ELISA试剂盒检测沙冬青种子总黄酮对小鼠脾淋巴细胞增殖和IL-2、IL-4生成的影响,以及总黄酮对肝脏KCs细胞的增殖和NO、NOS含量的影响;运用定量溶血分光光度法和血清溶血素HC₅₀测定法检测不同浓度沙冬青种子总黄酮对小鼠抗体生成细胞和血清溶血素的影响。结果显示,沙冬青种子总黄酮中主要活性成分为芒柄花素、7,3'-二羟基-4'-甲氧基黄酮、黄豆黄素和穗花杉双黄酮,其中,芒柄花素含量高达52.48%,其次为7,3'-二羟基-4'-甲氧基黄酮,含量为11.20%。在2.5~100 μg/mL总黄酮作用下,沙冬青种子总黄酮对脾淋巴细胞的增殖和细胞因子的产生具有明显的促进作用,尤其在20 μg/mL时脾淋巴细胞增殖率和IL-2的分泌量分别高达217.62%和159.661 pg/mL,与空白对照组相比差异极显著（P<0.01）;在40 μg/mL时,脾淋巴细胞IL-4的分泌量高达149.274 pg/mL,极显著高于空白对照组（P<0.01）。沙冬青种子总黄酮对KCs细胞的增殖及NO和NOS分泌也具有明显促进作用,在60 μg/mL时,与空白对照组相比,KCs细胞增殖率达67.77%,NO和NOS的分泌量分别达180.106和29.942 μmol/L（P<0.01）。此外,沙冬青种子总黄酮能明显促进小鼠体内抗体生成细胞和血清溶血素含量的增加。综上表明,沙冬青种子总黄酮主要活性成分为芒柄花素和7,3'-二羟基-4'-甲氧基黄酮。沙冬青种子总黄酮对小鼠免疫活性细胞的增殖、相关免疫细胞因子和抗体的产生与释放等都具有显著的促进作用。     

Seroepidemiology and genotyping of hepatitis E virus in Singapore reveal rise in number of cases and similarity of human strains to those detected in pig livers

Hepatitis E virus (HEV) causes 20 million infections worldwide yearly, of which only about 3.3 million are symptomatic. In developed Asian countries, HEV strains detected in human sera and in food sources were genetically similar, suggesting that indigenous HEV infections may be largely food‐borne. To assess the burden of hepatitis E in Singapore, we performed a seroepidemiologic study of the infection. Additionally, we carried out HEV genotyping on archived, residual HEV IgM‐positive serum samples collected between 2014 and 2016 (n = 449), and on pig liver samples (n = 36) purchased from wet markets and supermarkets. Our study shows a rise in hepatitis E incidence (IgM) from 1.7 to 4.1 cases per 100,000 resident population from 2012 to 2016 and an increase in hepatitis E IgG positivity rate among residents from 14% in 2007 to 35% in 2016. Other findings also suggest the epidemiology of hepatitis E in Singapore has shifted, from it being mainly a disease imported from the Indian subcontinent, to one that is now increasingly prevalent in our resident population. Genotypes obtained from 143 human samples identified the majority to be genotype 3 (n = 121), 21 to be genotype 1 and one to be genotype 4. Further phylogenetic analyses suggest genotype 3a to be the cause of indigenous infections in residents, which showed genetic similarity to the genotype 3a strains detected in pig livers. This link between the strains in the majority of human samples and those in pig livers consumed by the public suggests a possible food‐borne route of HEV infection in Singapore.