预测微生物学发展与水产品的安全控制

预测微生物学将食品微生物学与统计学结合起来,通过建立数学模型快速预测微生物的生长趋势,是控制水产品中微生物的良好方法,对于水产品的加工、生产的安全控制起到指导作用,同时对于货架期有合理的预测。预测微生物学将成为水产品安全控制的有力工具。     

窖泥微生物、窖泥酶活性与窖泥养分相关性研究

对泸州老窖4种不同窖龄的窖泥进行研究,结果表明,窖泥中微生物数量规律、窖泥土壤水解N、速效K、有机质含量均为400余年窖龄>100余年窖龄>40余年窖龄>20余年窖龄。窖泥中土壤微生物与土壤酶活性间均呈正相关。通过各因子对窖泥中土壤微生物总数、土壤酶活性的通径分析发现:速效P、水解N、蔗糖酶和过氧化氢酶是影响微生物总数量的主要因子。     

不同菌种制备大豆多肽的抗氧化活性比较研究

分别采用枯草芽孢杆菌、啤酒酵母菌以及黑曲霉菌发酵豆粕制备多肽,利用SephadexG-15凝胶过滤层析、SDS—PAGE电泳等方法进一步纯化,并对各组分进行抗氧化能力的研究。结果表明：采用枯草芽孢杆菌、啤酒酵母菌以及黑曲霉菌发酵豆粕得到多肽分别为13．512、12．462、14．752mg／mL。通／LSephadexG-15凝胶过滤层析分别得到的组分1分子质量范围分布在1055．67、1374．16、675．58u,组分Ⅱ分子质量范围分布在2031．49、2283．46、1625．54u。黑曲霉菌制备多肽原液及各组分清除3种自由基的作用较强,且组分1的清除效果好于组分2,其中对脂质过氧化物清除能力大于TBHQ,并与Vc相当。     

储藏温度对稻谷微生物和脂肪酸值的影响研究

通过模拟储藏,研究了高湿(85%)条件下温度对稻谷微生物区系和脂肪酸值的影响。结果表明:在85%湿度条件下,随着储藏时间的延长,霉菌量和脂肪酸值呈增加的趋势,细菌量呈先增加后减少趋势。方差分析得出储藏温度、时间对稻谷微生物区系和脂肪酸值有显著影响,相关性分析表明霉菌量、脂肪酸值与储藏温度和时间呈显著二元线性关系,而细菌量与储藏温度和时间呈极显著的二元二次曲线关系。进一步的研究表明稻谷脂肪酸值与霉菌量、温度呈极显著的二元线性关系,脂肪酸值随着霉菌量的增加和储藏温度的升高而逐渐增高。     

对虾养殖水体氨氧化菌的多样性分析与硝化作用的特征

为了研究珠三角地区不同空间分布的对虾养殖水体中氨氧化菌多样性的异同与探究养殖水体中氨氧化菌的硝化作用特征,应用PCR-DGGE技术,结合非加权算术平均法(UPGMA)聚类分析和多维尺度分析(MDS)的方法,对珠三角地区7个对虾养殖场的水样中氨氧化菌的多样性进行对比分析,继而构建了模拟养殖生态系统,评估了系统中微生物的硝化能力和硝化作用特征。结果表明:在养殖水体中,氨氧化古菌的类别明显少于氨氧化细菌,各样品间相似性较低,为41%到80%,没有高相似性的聚类;模拟系统中存在连续完整的亚硝化与硝化作用。     

冷却猪肉分割过程中微生物污染状况的研究

对冷却猪肉在分割过程中的主要接触物、分割肉本身的微生物污染和增殖情况进行研究。结果表明:分割过程中分割线上主要接触物的微生物数量随生产时间的延长而增加,传送带的微生物数量1h内达到1.89～2.48 lg(CFU/cm2),4h达到2.63～3.18lg(CFU/cm2);工人手、刀具、电锯和案板0.5h内微生物数量达到1.42～2.36 lg(CFU/cm2),2h达到1.84～3.08lg(CFU/cm2);初始冷却猪肉的微生物主要集中在胴体表层,在分割和精修过程中,冷却猪肉与污染物的接触,造成二次污染,不同部位分割冷却猪肉的微生物数量也不同,表面微生物数量在2.56～3.68 lg(CFU/cm2)之间,肉中微生物数量在3.18～3.97 lg(CFU/g)之间。     

Invited review: Plant polyphenols and rumen microbiota responsible for fatty acid biohydrogenation,fiber digestion,and methane emission: Experimental evidence and methodological approaches

The interest of the scientific community in the effects of plant polyphenols on animal nutrition is increasing. These compounds, in fact, are ubiquitous in the plant kingdom, especially in some spontaneous plants exploited as feeding resources alternative to cultivated crops and in several agro-industry by-products. Polyphenols interact with rumen microbiota, affecting carbohydrate fermentation, protein degradation, and lipid metabolism. Some of these aspects have been largely reviewed, especially for tannins; however, less information is available about the direct effect of polyphenols on the composition of rumen microbiota. In the present paper, we review the most recent literature about the effect of plant polyphenols on rumen microbiota responsible for unsaturated fatty acid biohydrogenation, fiber digestion, and methane production, taking into consideration the advances in microbiota analysis achieved in the last 10 yr. Key aspects, such as sample collection, sample storage, DNA extraction, and the main phylogenetic markers used in the reconstruction of microbial community structure, are examined. Furthermore, a summary of the new high-throughput methods based on next generation sequencing is reviewed. Several effects can be associated with dietary polyphenols. Polyphenols are able to depress or modulate the biohydrogenation of unsaturated fatty acids by a perturbation of ruminal microbiota composition. In particular, condensed tannins have an inhibitory effect on biohydrogenation, whereas hydrolyzable tannins seem to have a modulatory effect on biohydrogenation. With regard to fiber digestion, data from literature are quite consistent about a general depressive effect of polyphenols on gram-positive fibrolytic bacteria and ciliate protozoa, resulting in a reduction of volatile fatty acid production (mostly acetate molar production). Methane production is also usually reduced when tannins are included in the diet of ruminants, probably as a consequence of the inhibition of fiber digestion. However, some evidence suggests that hydrolyzable tannins may reduce methane emission by directly interacting with rumen microbiota without affecting fiber digestion.     

固定化生物硅藻土强化CAST工艺处理含盐污水研究

采用9%聚乙烯醇+0.5%海藻酸钠包埋耐盐菌群的固定化生物硅藻土小球投加到循环式活性污泥(CAST)反应器中,对比传统CAST工艺和投加固定化小球的CAST工艺对含盐污水COD和氨氮的去除效果,考察固定化生物硅藻土小球强化CAST工艺处理含盐污水性能。试验结果表明:在相同运行条件下,投加固定化生物硅藻土小球的CAST工艺出水COD、氨氮去除率基本维持在88%和90%以上,与传统CAST工艺相比分别提高了15%和10%。同时,向CAST工艺添加固定化生物硅藻土有助于维持反应器中微生物浓度稳定,提高出水水质及其稳定性。     

Advances in Transgenic Mouse Models to Study Infections by Human Pathogenic Viruses

Medical research is changing into direction of precision therapy, thus, sophisticated preclinical models are urgently needed. In human pathogenic virus research, the major technical hurdle is not only to translate discoveries from animals to treatments of humans, but also to overcome the problem of interspecies differences with regard to productive infections and comparable disease development. Transgenic mice provide a basis for research of disease pathogenesis after infection with human-specific viruses. Today, humanized mice can be found at the very heart of this forefront of medical research allowing for recapitulation of disease pathogenesis and drug mechanisms in humans. This review discusses progress in the development and use of transgenic mice for the study of virus-induced human diseases towards identification of new drug innovations to treat and control human pathogenic infectious diseases.