血浆蛋白粉对早期断奶仔猪的作用与应用研究概述

本文对血浆蛋白粉的特点、血浆蛋白粉对早期断奶仔猪的影响和在饲料中如何合理利用作一综述，为血浆蛋白粉的合理应用提供一定的理论基础．     

Cell surface-expression of the phosphate-binding protein PstS: System development, characterization, and evaluation for phosphorus removal and recovery

Simultaneous overabundance and scarcity of inorganic phosphate(P_i) is a critical issue driving the development of innovative water/wastewater treatment technologies that not only facilitate Pi removal to prevent eutrophication,but also recover P_i for agricultural reuse.Here,a cell-surface expressed high-affinity phosphate binding protein(PstS) system was developed,and its P_i capture and release potential was evaluated.E.coli was genetically modified to express PstS on its outer membrane using the ice nucleation protein(INP)as an anchoring motif.Verification of protein expression and localization were performed utilizing SDS-polyacrylamide gel electrophoresis(SDS-PAGE),western blot,and outer membrane separation analyses.Cell surface characterization was investigated through acid-base titration,X-ray photoelectron spectroscopy(XPS),and Fourier transform infrared spectroscopy(FTIR).These tests provided information on the macromolecular structure and composition of the bacteria surface as well as the proton-exchange properties of the surface functional groups(i.e.,pKa values).Phosphate desorption and adsorption batch experiments were conducted to evaluate the effects of temperature,pH,and ionic strength on phosphate capture and release.The PstS surface-displayed cells demonstrated greater potential to release and capture phosphate compared to non-modified cells.Higher temperatures up to 40℃,basic pH conditions(pH=10.5),and higher ionic strength up to 1.0 mol/L KCl promoted 20%-50% higher phosphate release.     

食物贸易视角下的全球食物供需平衡及其演化分析

用食物供给量与生产量分别表示食物的可及性与自给率,其差值可表示食物贸易量,以人均每天卡路里为单位进行的折算可以更好地反映膳食营养的变化。从食物贸易视角分析了28年来食物供需平衡状况,结果表明:（1）1986—2013年,全球食物贸易量增加1.5倍;食物总产量增加0.75倍,贸易量在总产量中的比例增加约8个百分点,相当于7.9×10⁸ t食物进入国际市场,这成为改善膳食结构的重要因素。（2）28年来,食物可及性与自给率呈上升趋势,全球绝大部分人口已经达到最低2200 kal的营养标准。（3）食物可及性、自给率、贸易量均存在地域差异,非洲及南亚的部分国家是低值地区。（4）总体来看,全球人均每天热量与蛋白质供给量增加。低收入国家增速最快,中等收入国家增速次之,高收入国家增速最慢。但非洲、东南亚等地的一些欠发达国家仍未达到最低的营养标准,全球仍有一部分人处于营养不良状态。     

微囊藻毒素和温度对萼花臂尾轮虫热激蛋白Hsp70水平的影响

微囊藻毒素(MCs)是由有毒蓝藻(尤其是铜绿微囊藻)产生的一类藻毒素,可对水生生物和人类健康造成严重危害,然而目前有关浮游动物对MC-LR胁迫的应激响应研究较为少见.因此,本文探究了微囊藻毒素MC-LR和温度对采自青海西宁的萼花臂尾轮虫(Brachionus calyciflorus)热激蛋白Hsp70水平的影响.结果表明,温度、MC-LR及其交互作用对萼花臂尾轮虫Hsp70含量具有显著影响.在各温度条件下,MC-LR均诱导了轮虫Hsp70水平的上调;虽然Hsp70的表达水平在低剂量MC-LR处理下上调不显著,但在高剂量MC-LR(6 mg·L-1)处理下上调却极为显著;另外,以24℃处理为对照组,在20和28℃温度胁迫下各MC-LR处理组轮虫的Hsp70含量均显著增加,但16℃实验组与24℃对照组间未见显著差异,这可能与诱导轮虫Hsp70表达的环境温度阈值或机体对低温环境的长期适应性进化和调节机制有关.     

缓冲液盐度对热提取活性污泥胞外聚合物的影响

采用热提取法提取污泥中微生物细胞外的胞外聚合物(Extracellular Polymeric Substance,EPS),分析了不同提取时间、提取温度、缓冲液盐度对污泥中EPS提取效果的影响,并采用平行因子模型(PARAFAC模型)分析了不同缓冲液盐度下EPS的荧光组分及特性,探究了缓冲液盐度对热提取污泥EPS的影响.结果表明,缓冲液盐度对热提取EPS的组分和荧光物质的强度均产生影响,0.50%的氯化钠缓冲液盐度条件下松散型EPS(loosely bound EPS,LB-EPS)组分含量及荧光物质最佳,0.05%氯化钠缓冲液盐度条件下紧密型EPS(tightly bound EPS,TB-EPS)的提取效果最佳;当提取时间为40 min,提取温度为70℃时,总EPS含量达(93.26±2.07)mg·g~(-1)(以VSS计);三维荧光结果显示,不同缓冲液盐度条件下污泥中EPS均包含类蛋白质(C1:λ_(Ex)/λ_(Em)=290 nm,302/350 nm)、类色氨酸(C2:λ_(Ex)/λ_(Em)=278 nm,340 nm)、类胡敏酸(C3:λ_(Ex)/λ_(Em)=310 nm,410 nm)和类腐殖酸(C4:λ_(Ex)/λ_(Em)=380/420 nm,474/514 nm)4类荧光组分峰,在溶解性EPS(SMP)和LB-EPS中类色氨酸的荧光强度最高,TB-EPS中类蛋白质荧光强度最高.因此,合适的热提取缓冲液盐度,有利于污泥EPS中各组分的高效提取.     

墨汁鬼伞对重金属铅离子的耐受与富集作用及其在铅离子胁迫下的差异表达蛋白鉴定

铅是已知毒性最大的重金属污染物之一,具有极强的积累性和不可逆性.生物修复环境重金属污染以其成本低、能实现对重金属回收等特点被认为是最有前景的修复技术.墨汁鬼伞被认为具有富集重金属离子的能力,本文首先通过在含Pb~(2+)的固体培养基上培养墨汁鬼伞分析了墨汁鬼伞对不同浓度Pb~(2+)的耐受能力,结果表明当Pb~(2+)浓度低于50 mg·L~(-1)的情况下,墨汁鬼伞的生长不会受到影响;随着Pb~(2+)浓度提高,墨汁鬼伞生长缓慢,菌丝稀疏,菌落形状不规则;当浓度高于500 mg·L~(-1)时,墨汁鬼伞生长明显被影响,并产生色素.进一步分析墨汁鬼伞对不同浓度Pb~(2+)的富集能力表明即使在Pb~(2+)浓度高达800 mg·L~(-1)的情况下,墨汁鬼伞仍然可以富集培养基中的94.7%的Pb~(2+).此外通过分析墨汁鬼伞的差异蛋白,鉴定到一个受Pb~(2+)诱导的14-3-3类蛋白.以上研究表明墨汁鬼伞可以用于环境重金属污染的生物修复.     

Exploration of the key functional proteins from an efficient cellulolytic microbial consortium using dilution-to-extinction approach

In the present study, the cellulose binding proteins(CBPs) secreted by a putative cellulolytic microbial consortium were isolated and purified by affinity digestion. The purified CBPs were subsequently separated by sodium dodecyl sulfate–polyacrylamide gel electrophoresis(SDS-PAGE). Using mass spectrometric analyses, eight CBPs were identified and annotated to be similar to known proteins secreted by Clostridium clariflavum DSM 19732 and Paenibacillus sp. W-61. In addition, in combination with dilution-to-extinction approach and zymogram analysis technique, CBPs 6(97 k Da) and 12(52 k Da) were confirmed to be the key functional proteins that influence cellulolytic activities. Moreover, structural domain analyses and enzymatic activity detection indicated that CBPs 6 and 12 contained glycoside hydrolase families(GH) 9 and 48 catalytic modules, which both revealed endoglucandase and xylanase activities. It was suggested that the coexistence of GH9 and GH48 catalytic domains present in these two proteins could synergistically promote the efficient degradation of cellulose.     

缫丝废液的综合利用

缫丝废液中含有丰富的蛋白质，直接排入严重污染环境，废液中的蛋白质能用化学或生物化学方面水解成有用的氨基酸，后者是化学，医药，食品，饲料工业的重要原料，本文报道了缫丝废液中蛋白质酸水解和酶水解的研究结果以及部分酶水解的规律。     

双菌发酵水葫芦压滤液生产单细胞蛋白的研究

水葫芦在我国多个地区泛滥,含水率超过90%,需要就地压滤处理。而由此产生的大量水葫芦压滤液富含纤维素和各种有机物,属于高浓度有机废水,容易造成二次污染,且在目前污水处理技术条件下处理成本较高。通过微生物发酵处理水葫芦压滤液生产单细胞蛋白,可以减少环境污染的同时提高资源的利用率。该试验利用糖化霉菌与酵母混合发酵以提高粗蛋白产量。35℃恒温条件下,当原始COD值为15333.33mg/L时,添加(NH)42SO425.0g/L,先以黑曲霉(Aspergillusniger)发酵40h,然后接种产朊假丝酵母(Candidautilis)酵母发酵32h,菌体回收率可达19.8g/L,COD去除率达到43.65%;当原始COD值为7280mg/L时,添加(NH)42SO46.0g/L,先以黑曲霉(Aspergillusniger)发酵48h,然后接种产朊假丝酵母(Candidautilis)酵母发酵24h,COD的去除率可达81.24%,菌体回收率达1.97g/L,粗蛋白含量达39.76%。     

绿色荧光蛋白标记的大肠杆菌海水中稳定性研究

用绿色荧光蛋白基因( GFP) 标记大肠杆菌K12(K12GFP),检测其在海水中的存活及稳定性.研究结果表明,K12与K12GFP微生物学特性差异不显著,而且两者在高压灭菌海水中的存活曲线也基本一致,说明K12GFP可为进一步研究K12在自然海水中的生态变化提供可靠依据.在高压灭菌海水中,K12GFP存活28 d之久,该菌密度随时间缓慢下降;在过滤海水中,K12GFP存活7 ,该菌密度从107CFU/mL降到102CFU/mL.表明海水的营养成分会对其存活产生较大影响.