Evaluation of the effects of colostrum replacer supplementation of the milk replacer ration on the occurrence of disease,antibiotic therapy,and performance of pre-weaned dairy calves

The objective of this study was to evaluate the effects of colostrum supplementation of the milk replacer ration on disease occurrence, antibiotic therapy, and performance of pre-weaned dairy calves with adequate transfer of passive immunity. Two hundred and two 1-d-old Holstein dairy calves were assigned to 1 of 2 groups after arrival to a dairy calf rearing facility. Calves assigned to the control group (n = 100) received milk replacer (28% crude protein and 20% crude fat) without colostrum inclusion twice daily. Calves assigned to the treatment group (n = 102) received 150 g of supplemental colostrum replacer powder added to their milk replacer twice daily for the first 14 d of life. Before group assignment, serum samples were collected from all calves to confirm transfer of passive immunity. Calves were evaluated daily until weaning (56 d of life) for signs of clinical disease as well as any treatment with antibiotics. Presentation of clinical disease and antibiotic treatment was recorded daily by personnel blinded to treatment allocation. Adequate transfer of passive immunity was confirmed in all calves at the start of the study and mean serum IgG values were similar among calves from treatment and control groups. The odds ratios of having abnormal feces and abnormal respiration during the pre-weaning period for calves from the treatment group were 0.15 and 0.46 the odds ratios of calves from the control group, respectively. The odds ratios of receiving antibiotic therapy during the pre-weaning period for calves from the treatment group were 0.09 the odds ratios of calves from the control group. Mean body weight and average daily gain at weaning were not significantly different among calves from the treatment and control groups. Colostrum replacer supplementation of the milk replacer ration was effective in reducing antibiotic therapy and occurrence of disease during the pre-weaning period.     

Transferable Antibiotic Resistances in Marketed Edible Grasshoppers (Locusta migratoria migratorioides)

Grasshoppers are the most commonly eaten insects by humans worldwide, as they are rich in proteins and micronutrients. This study aimed to assess the occurrence of transferable antibiotic resistance genes in commercialized edible grasshoppers. To this end, the prevalence of 12 selected genes [aac(6’)‐Ie aph(2″)‐Ia, blaZ, erm(A), erm(B), erm(C), mecA, tet(M), tet(O), tet(S), tet(K), vanA, vanB] coding for resistance to antibiotics conventionally used in clinical practice was determined. The majority of samples were positive for tet(M) (70.0%), tet(K) (83.3%) and blaZ (83.3%). A low percentage of samples were positive for erm(B) (16.7%), erm(C) (26.7%), and aac(6’)‐Ie aph(2″)‐Ia (13.3%), whereas no samples were positive for erm(A), vanA, vanB, tet(O), and mecA. Cluster analysis identified 4 main clusters, allowing a separation of samples on the basis of their country of origin.     

侧孢短芽孢杆菌S62-9的生物学特性研究

以实验室选育的一株侧孢短芽孢杆菌Brevibacillus laterosporus S62-9为对象,体外研究其耐热性、耐酸性、耐胆盐性、黏附性以及药敏性等生物学特性。结果表明,B.laterosporus S62-9耐热性较好,85℃水浴5 min,存活率达86.20%;人工胃液中作用4 h,p H 2.0下的存活率最低,为85.70%,p H 3.0和p H 4.0下的存活率均高于95.00%;人工肠液中作用4 h,胆盐浓度为0.1%、0.2%和0.3%时的存活率分别为93.30%,91.70%和88.30%;对模拟胃肠道消化过程的耐受性高,p H 2.0胃液处理2 h后又经0.3%胆盐处理3 h,存活率达96.00%;营养体状态的B.laterosporus S62-9对Caco-2细胞体外的粘附率为20.70 CFU/cells,黏附能力高于对照组枯草芽孢杆菌K1;对养殖中常用的10种抗生素均未产生耐药性,是安全菌株。B.laterosporus S62-9优良的体外益生菌特性符合微生态制剂菌株的选育标准和要求,为其微生态制剂的开发与应用奠定了理论基础。     

微波强化Fenton氧化法深度处理抗生素废水研究

采用微波强化Fenton氧化法对抗生素废水二级处理出水进行深度处理,通过正交试验和单因素试验得出最佳反应条件为:初始pH为3.0～4.0、H2O2投加量为5 mL/L、n(Fe2+)∶n(H2O2)为1∶10、微波功率为625 W。当抗生素废水二级出水COD为502～516 mg/L时,反应时间6 min,处理出水COD<120 mg/L,COD去除率达到78.0%以上,处理后出水水质满足《发酵类制药工业水污染物排放标准》(GB 21903—2008)。     

纯壳聚糖纤维关键技术研究及其产业化

简介了纯海洋动物再生纤维—壳聚糖纤维的理化性质、生物学特性、抑菌机理以及调节人体皮肤微生态平衡的保健功能。重点阐述了由废弃虾、蟹壳为原料,生产纯壳聚糖纤维的关键技术和全程无毒化纺丝的工艺优点,纯壳聚糖纤维在医药、工业、纺织等领域的应用现状,以及实现原料国产化及纤维产业化发展。     

Biochemistry of bacterial multidrug efflux pumps

Bacterial pathogens that are multi-drug resistant compromise the effectiveness of treatment when they are the causative agents of infectious disease. These multi-drug resistance mechanisms allow bacteria to survive in the presence of clinically useful antimicrobial agents, thus reducing the efficacy of chemotherapy towards infectious disease. Importantly, active multi-drug efflux is a major mechanism for bacterial pathogen drug resistance. Therefore, because of their overwhelming presence in bacterial pathogens, these active multi-drug efflux mechanisms remain a major area of intense study, so that ultimately measures may be discovered to inhibit these active multi-drug efflux pumps.     

3-氟-5-硝基苯甲氰的合成

以4-氟苯胺为原料,经N-乙酰化、硝化合成2-硝基-4-氟乙酰苯胺,所得产物经酸性水解脱乙酰基得4-氟-2-硝基苯胺,然后经溴化、重氮化、脱重氮基得1-溴-3-氟-5-硝基苯,最后经氰化合成了目标产物3-氟-5-硝基苯甲氰.产物用1HNMR进行表征.     

传统发酵食品中乳酸菌的安全性评估

本文以传统发酵食品中分离的38株乳酸菌(lactic acid bacteria,LAB)为研究对象,利用溶血试验、明胶液化试验和吲哚试验测试受试菌株相关产毒代谢产物,采用K-B纸片法检测菌株对25种抗生素的耐药表型,运用聚合酶链式反应检测菌株携带的耐药基因。结果表明:38株乳酸菌的溶血试验、明胶液化试验和吲哚试验均为阴性,说明菌株在生长代谢过程中不产生相关毒力物质;38株菌对头孢曲松、头孢噻肟、四环素、多西环素、氯霉素、克林霉素和红霉素表现敏感;对其余18种抗生素呈不同程度耐受,其中对磺胺异噁唑耐药率最高(52.63%),其次是卡那霉素(34.21%)、万古霉素(31.58%)、阿米卡星(26.32%)、链霉素(15.79%)、利福平(2.63%);耐药谱分析受试大部分乳酸菌存在多重耐药现象;PCR共检测出3种耐药基因,分别是氯霉素耐药基因cat A(2.63%)、万古霉素耐药基因van A(5.26%)、利福平耐药基因rpo B(42.11%)。结果表明从传统发酵食品中分离的38株乳酸菌不存在相关产毒代谢产物安全隐患,但对部分抗生素呈现出不同程度耐受,并且利福平耐药基因rpo B的检出率较高。本研究为传统发酵食品中乳酸菌安全评价体系的完善提供理论参考。