维生素E的生物学功能和安全性评价研究进展

维生素E是机体重要的脂溶性维生素,具有抗氧化、维持生育和调节免疫系统等诸多生物学功能.多数研究表明维生素E毒性较低,但高剂量的维生素E可引起机体内其他脂溶性维生素的缺乏,同时对免疫效果产生不利影响.本文对维生素E的生物学功能、吸收代谢特点和安全性评价进行了综述,旨在为在动物上制订维生素E的安全限量提供理论参考.     

鸡大肠杆菌iss基因的克隆测序及原核表达

本实验对鸡大肠杆菌O2血清型菌株进行iss基因克隆测序，并在此基础上设计出两对套式引物，分别对含信号肽Miss基因序列和不含信号肽Miss基因序列进行扩增，并与原核表达载体pGEX-6p-1连接进行原核表达。iss基因克隆测序的结果与两组国外发表Miss基因序列进行比对，其同源性达100％。SDS—PAGE鉴定显示融合蛋白获得了较理想的表达，融合蛋白分子量分别约为36kD和33kD。     

貉流产菌的分离鉴定

从流产貉的子宫内膜中分离到一种革兰氏阴性杆菌 ,经微生物学鉴定、证实 ,分离菌为有毒力的大肠杆菌 ,通过动物感染试验 ,确定该菌是导致貉流产死亡的病原菌     

Fecal carriage of multi-drug resistant and extended spectrum β-lactamases producing E. coli in household pigeons,Bangladesh

Antibiotic resistance and ESBL constitute a risk to human and animal health. Birds residing close to humans could mirror the spectrum of human associated antibiotic resistance. Household pigeons were screened in Bangladesh to shed light on human associated, as well as, environmental antibiotic resistance. Escherichia coli from pigeons (n = 150) were tested against 11 antibiotics. 89% E. coli isolates were resistant to one or more critically important human antibiotics like ampicillin, cefadroxil, mecillinam, ciprofloxacin, gentamicin and tigecycline. No carbapenamase-producers were detected and the lower ESBL prevalence (5%) in pigeons. ESBL-producing E. coli isolates had bla_CTX-M-15 genes. Pigeons shared some bacterial clones and had bird associated sequence types like E. coli ST1408. Fecal carriage of bacteria resistance of critically important human antibiotics, together with examples of shared genotypes among pigeons, indicate the human-birds and bird to bird transmissions are important in the epidemiology of antibiotic resistance.     

加减三黄汤对耐药大肠杆菌acrA mRNA表达水平的影响

为了解加减三黄汤对大肠杆菌耐药性的影响,采用实时荧光定量方法检测了外输泵acrA mRNA表达水平的变化。将100只昆明系小鼠分为阳性组(感染耐药性大肠杆菌2 751株和2 952株),阴性组,攻毒治疗组(2 751株+加减三黄汤,2 952株+加减三黄汤),8d后将鼠随机剖杀,取肝组织抹片培养大肠杆菌,做药敏试验,同时提取质粒,检测大肠杆菌外输泵基因acrA的mRNA表达量。结果显示,经加减三黄汤在体治疗后的大肠杆菌耐药性下降了,每μL中mRNA拷贝数为2 751株最高达1016,2 952株1015;用药后各菌株均有下降;相差极显著(P≤0.01),耐药性越大的拷贝数越多。表明加减三黄汤对耐药大肠杆菌外输泵基因acrA的mRNA表达水平影响与耐药性有一定的相关性。     

用丝素蛋白作壁材制备丝素蛋白-维生素E微胶囊的试验

以具有良好乳化性、稳定性及胶体特性的丝素蛋白溶液作为壁材,与维生素E共混后进行高温喷雾干燥,制备丝素蛋白-维生素E微胶囊。通过优化维生素E与丝素蛋白溶液的配比,提高微胶囊的成囊性能。当维生素E与1%丝素蛋白溶液的质量比为0.5∶1时,制备的微胶囊成囊性能较好,包埋率在90%以上,胶囊颗粒间大小相差不大,囊径在3～5μm之间,囊壁厚度在500 nm～1μm之间。推测丝素蛋白囊壁在高温喷雾干燥过程中其蛋白质结晶区结构发生变化,从而有利于提高对药物的缓释性能。     

Effect of eleutheroside B/E on proliferation and expression of PPARγ and TGF-β1 in HBZY-1 cells cultured with high glucose

AIM: To explore the effects and mechanism of eleutheroside (ETS) B or E on the proliferation of HBZY-1 cells treated with high glucose. METHODS: The HBZY-1 cells were cultured under high glucose condition. The 4th generation of HBZY-1 cells was used for determining the optimal cell density, which was consistent with the growth regulation curve of the cells. The cells were divided into 6 groups: low glucose (LG) group, high glucose (HG) group, high glucose plus ETS-B/E (low dose, medium dose and high dose) groups, and high glucose plus losartan (LTG) group. After all cells were treated with the corresponding drugs at 24 h, 48 h and 72 h, the inhibitory rate of the proliferation was measured, and the expression of TGF-β1 and PPARγ was detected by immunocytochemistry and Western blotting. RESULTS: The best cell density was 2 000 cells/well, which was complied with the basic rules of the cell growth, and high glucose significantly promoted the HBZY-1 cell proliferation. At each time point, the inhibitory effects of ETS-B/E were significantly different between HG group and LTG group on the proliferation of the HBZY-1 cells (P<0.05). The expression of TGF-β1 was significantly inhibited, and the expression of PPARγ was significantly promoted by ETS-B/E (P<0.05). ETS-E showed stronger effect than ETS-B (P<0.05) in a concentration- and time-dependent manner. CONCLUSION: ETS-B/E significantly inhibits the proliferation of HBZY-1 cells under high glucose condition by decreasing TGF-β1 expression and promoting PPARγ expression.     

一株可裂解耐黏菌素大肠杆菌噬菌体的分离鉴定及全基因组分析

为研究耐黏菌素大肠杆菌的噬菌体治疗方法,本研究以耐黏菌素大肠杆菌为宿主菌,采用双层琼脂平板法从山东烟台某养鸡场污水样中分离纯化得到裂解性噬菌体SDYTW1-F1-2-2。通过透射电镜观察,最佳感染复数,一步生长曲线,温度稳定性,酸碱度稳定性等生物学特性测定,并对其进行全基因组测序分析。结果表明：1）噬菌体SDYTW1-F1-2-2噬菌斑呈现透亮,外周无晕圈,形态学观察显示其具有可伸缩性尾鞘。2）生物学特性分析表明,噬菌体最佳感染复数为0.1,潜伏期为50 min,爆发期为40 min,爆发量为（331±9）PFU/cell。在温度4～40℃,pH为4～12的环境下,噬菌体活性较为稳定。3）通过噬菌体全基因组测序及核酸类型鉴定显示,该噬菌体基因组全长为74 752 bp,双链DNA,GC含量42.1%。在噬菌体基因组中共鉴定出121个编码蛋白（CDS）,包括结构组成、DNA代谢与复制和包装以及细菌裂解相关的功能基因,发现一个tRNA基因,且未检测到如stx-1等致病性基因和mcr-1等耐药基因相关的基因。综上,噬菌体SDYTW1-F1-2-2裂解谱较宽,具有良好的酸碱性、热稳定性以及安全...     

桉树速丰林鸡粪施用效应分析

采用随机区组设计开展桉树施用鸡粪的试验研究,对不同施肥处理的林分生长量、林相特征以及经济效益进行分析,结果表明,穴施0.5kg以上近似绝干的鸡粪作基肥,其施用优势明显,能显著提高林分生产力,叶片浓绿、宽大、肥厚,叶绿素含量较高,树势强壮,而且经济效益较好,2年生林分平均树高、胸径、材积和蓄积分别达8.0～8.5m、7.0～7.4cm、0.015 6～0.018 6m3和21.5～26.3m3·hm-2,比穴施钙镁磷肥0.5kg为基肥的分别提高9.5% ～15.8%、9.6% ～15.7%、31.1% ～56.3%和32.8% ～62.7%,其中尤以穴施0.75kg鸡粪的经济效益最好,投入产出比高达14.91.     

Multiple rotation yields for intensively managed plantations in the Amazon basin

Jari Celulose S. A. is a Brazilian-owned industrial enterprise located along the Jari River (the first major south-flowing tributary of the Amazon). The company produces bleached kraft pulp for international and domestic sales. The raw material of this pulp production comes from the 75,000 ha of intensively managed plantations of Pinus caribaea (Morelet) and Eucalyptus spp. harvested on 10- and 6-year rotations, respectively. All currently active Jari plantations were converted from primary forest between 1968 and 1982. Silvicultural practices have been modified over successive rotations, including plantation species changes, increased intensity of site preparation, fertilization, and chemical weed control. A review of data from the early 1970s to present indicates an increase in productivity over successive rotations and several plantation locations and soil types. The reasons for this improvement are primarily related to the higher levels of silvicultural inputs and dramatic genetic gains. The long-term sustainability of this productivity is discussed in terms of current and future inputs. This revised version was published online in June 2006 with corrections to the Cover Date.