光合细菌与酵母跨界融合(杂合)子发酵味精废水研究

光合细菌球形红假单胞菌（Ｒｈｏｄｏｐｓｅｕｄｏｍｏｎａｓ ｓｐｈａｅｒｏｉｄｅｓ）酿酒酵母（Ｓａｃｃｈａｒｏｍｙｃｅｓ ｃｅｒｅｖｉｓｉａｅ）细胞分别经溶菌酶和蜗牛酶脱壁形成原生质体，在聚乙二醇（ＰＥＧ）和Ｃａ＾２＋诱导下实现了真核与原核细胞的超远缘杂交，经抗菌素培养基初步鉴定，融合产物能同时在含有链霉素和制霉菌素的培养基中生长，而双亲细胞只能在含有单一抗菌素的培养基中生长，经初筛与得获得高絮弟性     

酿酒酵母吸附Pb(Ⅱ)的表面特性研究

为深入探讨酿酒酵母吸附Pb（Ⅱ）的微观作用机制,本文利用表面显微分析技术（SEM-EDS、TEM-EDS、AFM）研究了酿酒酵母细胞吸附重金属离子Pb（Ⅱ）前后的细胞表面变化.研究结果表明,酿酒酵母细胞与Pb（Ⅱ）作用后,细胞表面除吸附Pb（Ⅱ）外,同时产生大量更高浓度的含Pb（Ⅱ）沉淀,导致Pb（Ⅱ）从溶液中被去除.酵母与Pb（Ⅱ）反应前,酵母细胞表面可检测到的主要元素包括C、O、N、P、S、K、Mg;酵母与Pb（Ⅱ）作用后,细胞表面始终保持C、O、P吸收峰,而N、K、Mg、S吸收峰随反应条件不同而减弱、消失或增强.P作为细胞表面组分可能与Pb（Ⅱ）结合.酵母与Pb（Ⅱ）作用过程中,重金属离子促进酵母细胞释放细胞内含物.原子力显微镜（AFM）证实,云母片表面对酵母吸附Pb（Ⅱ）后细胞的铺展变形作用明显增大.     

Enhanced resistance of yeast mutants deficient in low-affinity iron and zinc transporters to stannous-induced toxicity

Tin or stannous (Sn²⁺) compounds are used as catalysts, stabilizers in plastic industries, wood preservatives, agricultural biocides and nuclear medicine. In order to verify the Sn²⁺ up-take and toxicity in yeast cells we utilized a multi-elemental analysis known as particle-induced X-ray emission (PIXE) along with cell survival assays and quantitative real-time PCR. The detection of Sn²⁺ by PIXE was possible only in yeast cells in stationary phase of growth (STAT cells) that survive at 25 mM Sn²⁺ concentration. Yeast cells in exponential phase of growth (LOG cells) tolerate only micro-molar Sn²⁺ concentrations that result in intracellular concentration below of the method detection limit. Our PIXE analysis showed that STAT XV185-14c yeast cells demonstrate a significant loss of intracellular elements such as Mg, Zn, S, Fe and an increase in P levels after 1 h exposure to SnCl₂. The survival assay showed enhanced tolerance of LOG yeast cells lacking the low-affinity iron and zinc transporters to stannous treatment, suggesting the possible involvement in Sn²⁺ uptake. Moreover, our qRT-PCR data showed that Sn²⁺ treatment could generate reactive oxygen species as it induces activation of many stress-response genes, including SOD1, YAP1, and APN1.     

啤酒酵母吸附Cu^2＋的模拟实验

研究了啤酒酵母吸附重金属Ｃｕ２＋离子的可行性及反应条件对去除作用的影响．结果表明：用啤酒酵母处理Ｃｕ２＋,在起始浓度ρ０为２０～４００ｍｇ／Ｌ的范围内,吸附量ｗ为２．９８～１２．０３ｍｇ／ｇ,说明用啤酒酵母去除重金属Ｃｕ２＋是可行的．吸附反应在１０～２０ｍｉｎ基本达到吸附平衡．最适反应温度（θ）和ｐＨ分别为１５～２０℃和４．０～６．０,酵母细胞有一最适投加用量．Ｆｒｅｕｎｄｌｉｃｈ吸附等温方程的分析表明,η与重金属离子种类有关,与酵母细胞种类关系较小;ｋ值与酵母种类和重金属离子种类有关．     

Ein neuer Biotest mit der HefeSaccharomyces cerevisiae auf aquatische Toxizit?t

Zusammenfassung  Die G?rleistung der HefeSaccharomyces cerevisiae wird als Bioindikator zur Erfassung aquatoxischer Wirkungen genutzt. Dazu wird die CO₂-Produktion der Hefezellen nach einer Vermehrungsphase unter toxischen Einflüssen gemessen. Als Kennwert (EC₂₀) dient die Schadstoffkonzentration, die die G?rung um 20% mindert. Es werden organische Verbindungen (unpolare und polare Narkotika), anorganische Salze (insbesondere von Schwermetallen), Tenside und Pflanzenschutzmittel geprüft. Die Ergebnisse werden, soweit verfügbar, mit den Daten eines Ciliatentestes mitTetrahymena pyriformis verglichen. Es ergab sich eine übereinstimmung von 90% bei vergleichbarer Testempfindlichkeit. Ergebnisse des Hefetests sind damit ?kotoxikologisch aussagef?hig. Der Test ist reproduzierbar, methodisch einfach zu handhaben und bietet eine Alternative für die Abwasserprüfung, da steriles Arbeiten nicht erforderlich ist. Online-First: 15. Juni 2000     

Evaluation of Saccharomyces cerevisiae strains as probiotic agent with aflatoxin B1 adsorption ability for use in poultry feedstuffs

In this study the aflatoxin B₁ (AFB₁) removal capacity, the tolerance to salivary and gastrointestinal conditions, autoaggregation and coaggregation with pathogenic bacteria of Saccharomyces cerevisiae strains isolated from broiler feces, were evaluated. Only four of twelve isolated strains were identified as Saccharomyces cerevisiae using molecular techniques. The results obtained in AFB₁ binding studies indicated that the amount of AFB₁ removed was both strain and mycotoxin-concentration dependent. Therefore, a theoretical model was applied in order to select the most efficient strain to remove AFB₁ in a wide range of mycotoxin concentration. The results indicated that S. cerevisiae 08 and S. cerevisiae 01 strains were the most efficient microorganisms in the mycotoxin removal. Viability on simulated salivary and gastrointestinal conditions was investigated and S. cerevisiae 08 strain showed the best results, achieving 98% of total survival whereas S. cerevisiae 01 reached only 75%. Autoaggregation and coaggregation assays showed S. cerevisiae 08 as the most appropriate strain, mainly because it was the unique strain able to coaggregate with the four bacterial pathogens assayed. Consequently, S. cerevisiae 08 is the best candidate for future in vivo studies useful to prevent aflatoxicosis. Further quantitative in vitro and in vivo studies are required to evaluate the real impact of yeast-binding activity on the bioavailability of AFB₁ in poultry. However, this study could be useful in selecting efficient strains in terms of AFB₁ binding and provide an important contribution to research into microorganisms with potential probiotic effects on the host.     

酿酒酵母对Ag+的吸附特性研究

为了深入探讨酿酒酵母吸附贵金属离子Ag⁺的特性,研究了吸附时间、离子浓度、初始pH值、温度对废弃酿酒酵母吸附Ag⁺的影响,并分析了动力学、热力学以及等温吸附特性.结果表明,酵母吸附Ag⁺的过程进行得很快,当Ag⁺初始浓度为1 mmol·L^-1、细胞浓度2 g·L^-1条件下,反应10 min,Ag⁺可以达到平衡吸附量的86%以上.随后在24 h内吸附量缓慢增加,去除率基本维持在51%～55%左右.酵母吸附Ag⁺的过程可以用准一级和准二级动力学方程描述,后者模拟效果更好.酵母吸附Ag⁺的等温吸附过程可以用Langmuir方程描述,但Freundlich方程拟合效果较差.当Ag⁺初始浓度为0～8 mmol·L^-1、酵母浓度2 g·L^-1条件下,酵母吸附Ag⁺的Langmuir理论饱和生物吸附容量为0.385 mmol·g^-1.在pH 2.0～7.2范围内,吸附量随着溶液初始pH值升高而升高.10～40℃范围内,温度对酵母吸附Ag⁺的影响不如pH值的影响显著,特别是在低离子浓度下尤其如此.酵母吸附Ag⁺的较适宜温度为20～30℃.热力学分析表明,酵母吸附Ag⁺具有自发性、熵增特征.     

Role of the vitamin E model compound Trolox in the prevention of Cr(VI)-induced cellular damage

Given the wide industrial use of chromium (Cr) and its environmental contamination, chromium represents a risk to humans exposed to the metal. Considering that Cr(VI) is a potent oxidizing agent that increases intracellular oxidation and DNA damage, it would be worth considering the pretreatment of cells with antioxidants as a means of preventing Cr(VI)-induced toxicity. The objective of this study was to pretreat yeast cells with the water-soluble vitamin E analogue Trolox in an effort to increase cell tolerance against reactive chromium and reactive oxygen species formed during Cr(VI) reduction. Results revealed a decrease in Cr(VI)-induced cytotoxicity and mitotic gene conversions in Trolox-pretreated cells. The protective effect of Trolox in Cr(VI) induced genotoxicity was confirmed also with the prokaryotic Salmonella typhimurium SOS/umu test. Pretreatment of cells with Trolox (1) increased total Cr bioaccumulation, (2) decreased Cr(VI)-induced intracellular oxidation, (3) decreased Cr(V) persistence and (4) increased OH^? formation in yeast extracts. These findings might be useful in directing future investigations concerning the use of Trolox as a human antioxidant supplement, and in clinical applications related to Cr-induced genotoxicity in occupational and environmental situations where chromium is a problem.     

离子液体氯化1-辛基-3-甲基咪唑对酵母细胞增殖生长和细胞膜通透性的影响

为探讨咪唑类离子液体氯化1-辛基-3-甲基咪唑([C₈mim][Cl])对酵母细胞的增殖生长和细胞膜通透性的影响,以不同浓度的[C₈mim][Cl]处理酵母细胞,研究离子液体对酵母细胞增殖和菌落形成的影响,通过测定酵母细胞外液蛋白质和核酸的含量,判断膜通透性的大小和[C₈mim][Cl]对细胞膜性结构的损伤。结果显示,0.1 mmol·L^-1的[C₈mim][Cl]延长了酵母细胞到达对数生长期的时间,在6～9 h之间对酵母细胞的增殖存在明显的抑制作用。1 mmol·L^-1的[C₈mim][Cl]使酵母细胞增殖不能到达对数生长期,对酵母细胞的增殖一直具有较强的抑制作用。随着离子液体浓度的增加,小菌落的数量增多。当平板内[C₈mim][Cl]浓度达到10 mmol·L^-1时,完全抑制了菌落的形成。[C₈mim][Cl]处理酵母细胞后,细胞外液中OD₂₈₀、OD₂₆₀的值显著升高。研究表明,细胞膜等膜性结构通透性的增加是离子液体[C₈mim][Cl]抑制酵母细胞增殖生长的原因之一。     

利用QSAR模型探讨分类条件下金属离子性质与酵母吸附容量之间的关系

在金属离子分类基础上(按金属离子的软硬性质),以啤酒工业废酵母对10种金属离子(Pb2 ,Ag ,Cr3 ,Cu2 ,Zn2 ,Cd2 ,Co2 ,Sr2 ,Ni2 、or Cs )的Langmuir理论饱和吸附容量qmax为QSAR(Quantitative Structure Activity Relationships)模型的活性参数,以金属离子的22种物理化学性质作为QSAR模型的结构参数,利用QSAR方法建立了分类条件下离子性质与酵母生物吸附容量之间的定量关系.金属的离子性质与吸附容量之间的线性回归分析结果表明,对金属离子进行适当分类可以改善拟合效果对于含有软离子的金属离子,共价指数X2mr是22种变量中预测效果最好的离子性质.离子的X2mr数值越大,离子与细胞的共价结合程度越高,吸附量越大.对于不含软离子的金属离子,极化力Z2/r、第一水解常数|log KOH|和电离势IP是qmax预测中最有价值的3个离子结构参数.(似)极化力的多种表征形式Z/r,Z/r2,Z/AR2,Z/AR也可以用于预测qmax.但考虑了金属离子的价层电子数、离子有效电荷和离子半径的极化力参数Z*2/r,却难以解释酵母吸附金属离子的亲和力顺序.该研究为预测金属离子的生物吸附容量、研究重金属离子-微生物的相互作用提供了新的思路和方法