废弃菌体水解液作氮源发酵产腈水合酶的研究

工业生产中微生物细胞在发酵结束后常被作为废弃物丢弃,容易造成环境污染和资源浪费.对废弃细胞进行破壁处理,废弃菌体水解液可替代酵母膏作有机氮源用于发酵产腈水合酶.通过采用超声波、冻融、热碱3种方法破碎细胞,测定水解液中氨基氮含量的高低,确定选择热碱法为最佳细胞破碎方法.通过正交实验选出最优破壁条件为:N aOH加入量5g.L-1,水解温度100℃,水解时间1.5h.在最佳破壁条件下,细胞破碎液中氨基氮含量为24.5 g· L-1.并考察了酵母膏与水解液的不同配比对腈水合酶发酵酶活的影响,确定了酵母膏与废弃菌体水解液的最佳配比为3:2.实验结果表明:利用热碱法处理废弃菌体的水解液作为氮源部分代替酵母膏,发酵酶活为1 063万U·mL-1,而完全利用酵母膏作为氮源的发酵酶活为1 055万U·mL-1.     

啤酒废酵母的综合利用研究进展

分析了啤酒废酵母中的有效成分及研究利用现状,同时对啤酒废酵母的破壁问题进行了讨论.     

含有嗜杀质粒的核融合缺陷突变株原生质体制备及再生条件的研究

利用由藤黄节杆菌(Arthrobacter latevs)分泌的,以β—1.3葡聚糖酶为主的酵母细胞壁溶解酶(Zymolyase),对含有嗜杀质粒的核融合缺陷突变株5045(α,his4,karl—1[KIL—K_1]rho~+)进行破壁,得到该菌株破壁,再生的最佳条件。为嗜杀酵母原生质体融合育种提供了依据。     

不同破壁方法对海洋毕赤酵母提取物的提取及应用

摘要:海洋酵母作为重要的微生物资源越来越受到重视. 本实验以从红树林沉积物中分离的海洋酵母?Pichia guilliermondii SY-19菌株作实验材料,制成质量浓度分别为5%、7.5%及10%的细胞悬液,用蜗牛酶法、双酶法（甘露聚糖酶和-葡聚糖酶）及热碱法等3种方法分组进行破壁处理12 h,每3 h检测1次酵母细胞数量及多糖、蛋白质、氨基氮和核酸等营养物质的含量,计算得率,确定合适的方法制备酵母提取物;对经有害无机氮胁迫处理2周的凡纳滨对虾,分别以配合饲料、菌液拌料和酵母提取物拌料投喂3周,比较对虾的存活率及生长状况. 结果表明,热碱法处理的破壁率和核酸提取量最高,但其他营养物含量稳定性差;而双酶法处理的蛋白质、氨基氮和多糖的得率最高且营养保留效果较好,以该法最佳条件即5% 酵母悬液处理12 h制备酵母提取物作为饲料添加剂。胁迫过的对虾经3周的饲养恢复,其增重和存活率表现为酵母提取物拌料饲喂的对虾最高（77.674.62%, 2.790.11g）,菌液拌料饲喂的次之（62.009.90%, 2.440.16 g）,未拌料的最低（53.6712.91%, 2.190.02 g）,对虾存活率上三组有显著差异（p0.05）,添加酵母提取物的与未拌料对照组的终体重存在显著差异（p0.05）。本文的研究结果表明该菌株在对虾健康养殖中具有较好的潜在价值.     

酿酒酵母钙调蛋白依赖性激酶-2的过量表达及其在氧化胁迫应答中的作用初探

利用PCR方法扩增钙调蛋白依赖性激酶（CaM-dependent kinase ,cmk）-2基因的蛋白质编码序列,经限制性内切酶Kpn I和BamH I酶切后连接入空载体pYES2/NTA构建真核表达载体,构建的pYES2/NTA-cmk2转化酿酒酵母菌株BY4741进行真核表达.经诱导和收集细胞后,对酵母细胞用玻璃珠震荡破壁,收集上清液进行镍离子亲和层析,并纯化Cmk2,纯化的蛋白通过Western blot检测.并且初步研究了Cmk2在酵母细胞氧化胁迫应答中的作用.     

雨生红球藻提取虾青素不同机械破壁方法的研究

对雨生红球藻厚壁孢子细胞的几种常用机械破壁方法的工艺条件分别进行研究,得到高压均质法,超声波法和冻融法的较优工艺条件.并分别在上述几种机械破壁方法的最佳工艺条件下比较了几种不同破壁方法对破壁率和虾青素提取率的影响.结果表明,高压均质法最适合于雨生红球藻厚壁孢子的破碎和虾青素的提取.高压均质的优化条件为:40MPa,循环3次,室温,破壁率达到91.4%,虾青素提取率为28.0μg mg(细胞干重),比未经破壁处理的提取率提高了10.1μg mg(细胞干重),提高了56.3%.     

甘草微粉细胞破壁率测定

建立了甘草微粉细胞破壁率检测的方法。采用细胞计数法,考察超细粉碎技术对甘草细胞破壁率的影响,测定甘草微粉的细胞破壁率。甘草细粉称样量与完整细胞计数的回归分析结果表明,两者显著相关(P<0.01),甘草经超细粉碎后细胞破壁率为91.14%。因此,以木栓细胞为计数指标的甘草粉末细胞破壁率测定方法简便、稳定、可靠。     

不同破壁方法获取海洋毕赤酵母提取物及其应用

以从红树林沉积物中分离的海洋毕赤酵母(Pichia guilliermondii) SY-19菌株为实验材料,制成质量分数分别为5.0%、7.5%及10.0%的细胞悬液,用蜗牛酶法、双酶法(甘露聚糖酶和β-葡聚糖酶)及热碱法分组进行破壁处理12 h,每3 h检测1次酵母细胞数量及多糖、蛋白质、氨基氮和核酸等营养物质的含量,计算破壁率和得率,确定制备酵母提取物的最佳方法,并利用最优方法制备酵母提取物拌料,对经有害无机氮胁迫处理2周的凡纳滨对虾(Litopenaeus vannamei)分别以配合饲料、菌液拌料和酵母提取物拌料投喂3周,比较对虾的存活率及生长状况.结果表明:用双酶法、以质量分数5.0%的酵母悬液处理12 h,蛋白质、氨基氮和多糖的得率最高,营养保留效果最好;所制备酵母提取物作为饲料添加剂,对胁迫过的对虾经3周的恢复饲养,酵母提取物拌料饲喂的对虾的存活率、体质量最高(77.67%±4.62%,2.79±0.11 g),菌液拌料饲喂的次之(62.00%±9.90%,2.44±0.16 g),未拌料的最低(53.67%±12.91%,2.19±0.02 g),差异有统计学意义(P0.05).     

牡丹花瓣冻干粉极细粉细胞破壁率的测定及营养成分分析

采用细胞计数法，以薄壁细胞为评价指标，测定牡丹花瓣冻干粉超细粉碎极细粉的细胞破壁率；营养成分按照食品安全国家标准相关实验方法和要求进行检测。建立牡丹花瓣冻干粉极细粉细胞破壁率的检测方法；测定牡丹花瓣冻干粉营养成分含量。结果表明，该方法可用于牡丹花瓣冻干粉极细粉细胞破壁率检测；牡丹花瓣冻干粉极细粉细胞破壁率为100%;牡丹花瓣冻干粉富含多种营养成分，具开发利用的价值。     

啤酒酵母泥中蛋白质的提取

从啤酒酵母泥中提取有益物质,不仅可以提高啤酒厂的经济效益,而且降低啤酒废酵母的污染负荷。研究了啤酒酵母蛋白的提取工艺,确定了主要工艺路线。实验中采用1 moL/L的Tween20作为表面活性剂和180分钟的超声破碎,啤酒酵母细胞的破壁率达到了68.67%,提取物酵母蛋白的产率为0.106 mg/mL。     

产朊假丝酵母细胞和细胞壁对铜离子吸附能力观察

通过比较产朊假丝酵母细胞与分离纯化的细胞壁对铜离子吸附能力差异,探讨了细胞壁在酵母吸附重金属离子过程中的作用。结果表明,细胞壁吸附的铜离子量通常是细胞吸附量的50% 以上。说明细胞壁是酵母吸附重金属离子的主要部位。     

Disruption of the actin cytoskeleton in yeast capping protein mutants

Capping protein controls the addition of actin subunits to the barbed end of actin filaments and nucleates actin polymerization in vitro. Capping protein has been identified in all eukaryotic cells examined so far; it is a heterodimer with subunits of relative molecular masses 32,000-36,000 (alpha-subunit) and 28,000-32,000 (beta-subunit). In skeletal muscle, capping protein (CapZ) probably binds the barbed ends of actin filaments at the Z line. The in vivo role of this protein in non-muscle cells is not known. We report here the characterization of CAP2, the single gene encoding the beta-subunit of capping protein in Saccharomyces cerevisiae. Yeast cells in which the CAP2 gene was disrupted by an insertion or a deletion had an abnormal actin distribution, including the loss of actin cables. The mutant cells were round and large, with a heterogeneous size distribution, and, although viable, grew more slowly than congenic wild-type cells. Chitin, a cell wall component restricted to the mother-bud junction in wild-type budding yeast, was found on the entire mother cell surface in the mutants. The phenotype of CAP2 disruption resembled that of temperature-sensitive mutations in the yeast actin gene ACT1, indicating that capping protein regulates actin-filament distribution in vivo.     

Plant degradation: a nematode expansin acting on plants

Expansin proteins, which have so far been identified only in plants, rapidly induce extension of plant cell walls by weakening the non-covalent interactions that help to maintain their integrity. Here we show that an animal, the plant-parasitic roundworm Globodera rostochiensis, can also produce a functional expansin, which it uses to loosen cell walls when invading its host plant. As this nematode is known to be able to disrupt covalent bonds in plant cell walls, its accompanying ability to loosen non-covalent bonds challenges the prevailing view that animals are genetically poorly equipped to degrade plant cell walls.     

Disruption of retinogeniculate afferent segregation by antagonists to NMDA receptors.

Afferent activity has an important role in the formation of connections in the developing mammalian visual system. But the extent to which the activity of target neurons shapes patterns of afferent termination and synaptic contact is not known. In the ferret's visual pathway, retinal ganglion cell axons from each eye segregate early in development into eye-specific laminae in the lateral geniculate nucleus (LGN). The dorsal laminae (termed laminae A and A1) then segregate further into inner and outer sublaminae that retain input from on-centre and off-centre retinal axons, respectively. Thus, individual retinogeniculate axons form terminal arbors within laminae A and A1 that are restricted to one inner or outer sublamina. We report here that blockade of N-methyl-D-aspartate (NMDA) receptors on LGN cells with specific antagonists during the period of sublamina formation prevents retinal afferents from segregating into 'On' and 'Off' sublaminae. Retinogeniculate axons have arbors that are not restricted appropriately, or are restricted in size but inappropriately positioned within the eye-specific laminae. NMDA receptor antagonists may specifically disrupt a mechanism by which LGN neurons detect correlated afferent and target activity, and have been shown to reduce retinogeniculate transmission more generally, causing LGN cells to have markedly reduced levels of activity. These results therefore indicate that the activity of postsynaptic cells can significantly influence the patterning of inputs and the structure of presynaptic afferents during development.     

热带假丝酵母二型性菌体细胞的形态和结构差异

用光学显微镜和电子显微镜研究热带假丝酵母（Candida tropicalis)的二塑性，菌丝体（M）和单细胞酵母（Y）形态差异很大，M是长管状多,细胞 相连，Y则是球形的单个细胞，内部结构上也体现了与其形态的相适应性，M菌丝顶端大的液泡为菌丝的延伸提供压力，但当顶端生长芽管时，大液泡会分裂成小液泡，部分小液泡进入芽管；菌丝顶端和侧面的泡囊，与其顶端生长和侧枝发生有关，单细胞酵母中，靠近母细胞和子细胞相连的部位，有些囊泡和颗粒物质，可能与细胞的新壁形成和分开有关。     

利用酵母菌SC_(0414)快速测定工业废水毒性

本文提出一种简单而快速的水样毒性监测方法.实验的基本原理是利用酵母菌SC_(0414)呼吸链中脱氢酶的氧化还原作用,以INT作指示剂,使INT还原为红色的INT-甲臢,在细胞内出现红色颗粒.当受到毒物作用时,其氧化还原活性被抑制.根据有无红色颗粒出现可以判断呼吸细胞和非呼吸细胞,并分别记录各自的细胞数,通过直线回归分析,可以推算出EC_(50)(半数作用浓度).这种新方法与瓦勃氏呼吸仪相比较,其优点是更为简单、快速.     

基于电动现象的细胞光镊阱力测量

提出了一种新的细胞光阱力标定的实验方法，利用细胞电泳原理，设计并研制了一套符合用光镊测力的电动样品池系统，用它替代单光镊操作系统中的普通样品池和高精密压电位移驱动平台，可以用电压调控细胞运动速度，系统相对简单、经济．实验测量结果为：在2～18V／cm电压梯度范围内，酵母细胞的运动速度与电压梯度成正线性关系，即在皮牛量级以下，最大光阱力与光镊光源的功率成线性增加关系．测量结果表明，该方法可实现对细胞光阱力的测量，还可用来测量细胞表面电量．     

Arabidopsis boron transporter for xylem loading

Boron deficiency hampers the productivity of 132 crops in more than 80 countries. Boron is essential in higher plants primarily for maintaining the integrity of cell walls and is also beneficial and might be essential in animals and in yeast. Understanding the molecular mechanism(s) of boron transport is crucial for alleviating boron deficiency. Here we describe the molecular identification of boron transporters in biological systems. The Arabidopsis thaliana mutant bor1-1 is sensitive to boron deficiency. Uptake studies indicated that xylem loading is the key step for boron accumulation in shoots with a low external boron supply and that the bor1-1 mutant is defective in this process. Positional cloning identified BOR1 as a membrane protein with homology to bicarbonate transporters in animals. Moreover, a fusion protein of BOR1 and green fluorescent protein (GFP) localized to the plasma membrane in transformed cells. The promoter of BOR1 drove GFP expression in root pericycle cells. When expressed in yeast, BOR1 decreased boron concentrations in cells. We show here that BOR1 is an efflux-type boron transporter for xylem loading and is essential for protecting shoots from boron deficiency.     

羧基在酵母菌生物吸附铅时的作用

用不同方法研究了酵母菌吸附重金属的机理.电位滴定法的结果说明生物材料含有0.5 mmol/g的酸性基团;酯化后的酵母菌对重金属的吸附量显著下降.对酯化前后的生物材料的红外光谱进行了比较,1 744 cm-1的吸收峰强度的增加证明酵母菌发生了酯化过程.羧基在酵母菌结合铅时起重要作用.     

酵母对锗的富集作用

以ＧｅＯ２为锗源，用微生物学方法，对３属７株酵母富集锗的效应进行了研究。试验证明，酵母对锗有较强的耐受力，并能将锗吸收到细胞内部，而不是吸附与滞留于细胞壁表面，这种吸收是一种主动吸收作用，受诸因素的直接影响。含锗酵母营养丰富，有生物活性，比对照酵母有更广阔的应用前景。