BD Phoenix^TM酵母菌鉴定板对临床分离酵母菌鉴定能力的评估

目的 评估BD Phoenix^TM酵母菌鉴定板对酵母菌的鉴定能力.方法 选取白念珠菌18株,热带念珠菌22株,光滑念珠菌19株,克柔念珠菌8株,近平滑念珠菌20株,新生隐球菌14株,季也蒙念珠菌4株,平常念珠菌1株,葡萄牙念珠菌1株,头状地霉2株,挪威念珠菌1株,链状念珠菌1株,乳酒念珠菌1株,希木龙念珠菌1株,解脂念珠菌3株,皱褶念珠菌1株,菌膜念珠菌3株,共计120株.借助Phoenix^TM 100全自动微生物鉴定仪,使用BD Phoenix^TM酵母菌鉴定板鉴定上述菌株.用真菌通用引物ITS1与ITS4对所有受试菌株的rDNA进行PCR扩增,对PCR产物进行序列测定、分析并作为金标准与BD Phoenix^TM酵母菌鉴定板的结果比较,同时使用MALDI-TOF MS质谱分析对试验菌株进行菌种鉴定.结果 BDPhoenix^TM酵母菌鉴定板除了对1株挪威念珠菌、1株平常念珠菌、1株解脂念珠菌、1株皱褶念珠菌未能鉴定以及1株链状念珠菌、1株克柔念珠菌、2株菌膜念珠菌、1株解脂念珠菌鉴定错误外其余试验菌株鉴定均正确,鉴定准确率为92.5％.所有鉴定结果均在17 h内获得,而白念珠菌、热带念珠菌、近平滑念珠菌的鉴定时间均小于6h,并且不受推荐培养基的限制.所有菌株MALDI-TOF MS的鉴定结果与其rDNA ITS序列分析的结果完全一致.结论 BD Phoenix^TM酵母菌鉴定板对多数酵母菌能够快速准确地鉴定到种,但对某些少见酵母菌的鉴定能力有待进一步考证.     

西藏雪层中酵母菌的分离鉴定

西藏地区因受气候条件的影响,人烟稀疏。故对此地区的自然环境、牛态及资源的研究均少见报道。但此处地域辽阔,有着宽广无根的雪地。研究西藏雪层中生物及微生物生长方面的厂作,可加强人们认识、保护、利用远边地区的自然环境。我们在西藏希夏邦马峰的积雪中,对雪面不同地段的气样每隔5cm深度作一层编号取样,并取6层次雪样。将其进行分离培养,结果显示在2展市样中有较典型的酵母菌。l材料与方法回,。I豆．且培养基及样品无机盐培养基;酵母膏、蛋白陈琼脂培养基;马铃薯、葡萄糖琼脂培养基;糖发酵基础培养基及无维生素基础培养基。…     

苯甲醛高耐受性酵母菌的选育

介绍一种经过长期诱导、驯化作用来选育耐性菌株的方法。通过固定化细胞的间歇补料培养方式和长期诱导、驯化后,筛选出8株具有较高苯甲醛耐受性的酿酒酵母菌株,其中菌株Sbht-35-23对苯甲醛的耐受性达到0．9％,并保持较高的稳定活性。采用这些具有较高耐性的酿酒酵母菌株生物合成L-苯基乙酰基甲醇(L-PAC),将有利于提高转化率。     

水质净化酵母菌的分离筛选及鉴定

摘要:【目的】针对目前水产养殖专用优良菌种资源缺乏的现状,从养殖环境和养殖生物体中分离筛选具有水质净化功能的酵母菌,并对优良菌株进行鉴定。【方法】在低温和常温条件下从皮皮虾、南美白对虾肠道及养殖池底质活性污泥中分离具有水质净化功能的酵母菌,在模拟水体中对分离菌株的水质净化能力进行筛选,并对优良菌株采用形态、生理生化实验及5.8S rDNA ITS序列分析进行鉴定。【结果】从3种介质中共分离到酵母菌37株,其中常温分离16株,低温分离21株。水质净化实验结果表明,常温分离的16株酵母菌中有5株,低温分离的21株酵母菌中有6株对模拟水体中亚硝态氮和氨氮有显著的去除效果;其中低温分离的DN9和常温分离的CN6 48h能将10.64mg/L的亚硝态氮彻底转化,96h对630mg/L CODcr的去除率分别达52%和67%。DN9和CN6均产红色色素,经形态特征、生理生化特性及5.8S rDNA基因序列分析,鉴定菌株CN6为沼泽生红冬胞酵母(Rhodosporidium paludigenum),DN9为胶红酵母(Rhodotorula mucilaginosa)。【结论】红酵母DN9和CN6能有效去除养殖水体中的有机污染物和亚硝态氮,有望开发成 水产养殖水质净化高效微生态制剂。     

酵母菌分类中泛醌类型的一种快速简便的鉴定方法

泛醌类化合物(简称UQ)是生物体内的一类非极性化合物,在电子传递及氧化磷酸化中起重要作用。近年来,已普遍将它作为酵母化学分类的一种指标。泛醌作为分类指征的基础在于其异戊烯基侧链单元的长度。存在于酵母细胞中的泛醌类型通常为UQ_6、UQ_7、UQ_8、UQ_9、UQ_(10)。目前,对酵母菌泛醌类型的确定     

醇化烟叶酵母菌分离鉴定及其生物学特性研究

采用涂布培养法和富集培养法对醇化烟叶样品中酵母菌进行了分离,富集培养法分离到23株,涂布培养法分离到6株。29株酵母菌的生物学特性研究表明,其中果胶酶、蛋白酶、淀粉酶、脂酶、纤维素酶、酚类利用、木质素利用、尼古丁降解、发酵产物气味等试验呈阳性的菌株数分别是1、10、0、3、10、22、1、21和29株。利用ATB系统,将ATY1、ATY8和ATY27等3株酵母菌分别鉴定为黏红酵母(Rhodotorula glutinis)、罗伦隐球酵母(Cryptococcus laurentii)和粗壮假丝酵母(Candida valida),各菌株鉴定结果的符合率分别为99.4%、98.2%和89.9%。研究结果表明,醇化烟叶中酵母菌种群数量较小,但酵母菌的生物学特性有利于烟叶醇化,值得进一步深入研究。     

临床常见酵母菌的特征和鉴定

自然界酵母有500多种,但能致病的只有20多种,主要见于念珠菌属、隐球菌属、球拟酵母、丝孢酵母属和地霉属。酵母的特性：以芽殖为主的单细胞真菌,菌落呈乳酪样,无毛样气生菌丝（见图1）。对人类有致病性的酵母可依菌落形态分为两类：一类是酵母菌：单细胞,呈圆形或卵圆形,以母细胞产生芽胞而繁殖,不形成有性孢子。当酵母菌生长于固体培养基时,其形成的菌落与细菌菌落较为类似,不同于霉菌的粉状菌落,如隐球菌即属于此类。另一类是类酵母样真菌：圆形或卵圆形细胞,以出芽生殖而繁殖,有芽生孢子、菌丝,无子囊。     

产棕榈油酸酵母菌的分离和鉴定

1992年分离到一株高产棕榈油酸的酵母菌。该菌株产油脂量为菌体干重的32.06％,棕榈油酸占油脂总量的52.14％,经初步鉴定认为是一株酿酒酵母Saccharomyces cerevisiae。     

内蒙古西部区酸粥中酵母菌的分离鉴定及优势菌分析

从内蒙古地区采集28份酸粥样品,从中分离出40株酵母菌,并对其进行了分子生物学鉴定和生物多样性分析。26S rDNA D1/D2区域 (600bp左右)碱基序列分析结果表明,酸粥中的酵母菌有Issatchenkia orientalis、Saccharomyces cerevisiae、Geotrichum sp.、Candida pararugosa、 Candida parapsilosis、Trichosporon asahii、Trichosporon coremiiforme、Clavispora lusitaniae和Candida tropicalis。经过分析,Issatchenkia orientalis(75%,Frequency percentage)为酸粥中的优势菌。     

论植物发酵和酵素

本文根据作者多年从事发酵工业科研与生产实践的经验,结合自身对酵素的认识和理解,就酵素的起源、机体抗衰老学说、植物原料的微生物发酵与几种药食两用植物和水果经微生物发酵而提高其生物活性的研究作了介绍,最后就酵素的发展提出了建议。     

三种观赏植物对重金属镉的耐性与积累特性

通过盆栽实验,对镉(Cd)胁迫下3种观赏植物含羞草、白雪姬和树马齿苋的生长、生理和重金属累积与分布情况进行了研究。结果表明:含羞草、白雪姬和树马齿苋的平均耐性指数分别为105.57、81.35和79.88;在100mg.kg-1Cd浓度下三者叶绿素a、b的含量分别为对照的83.74%、69.83%;60.64%、51.26%和60.64%、51.26%;类胡萝卜素的含量和叶绿素a/b值无明显变化;三者在Cd胁迫下均表现出O2.-离子生成速度上升,MDA含量增加,电导率升高的趋势,其中含羞草的变化幅度最低,白雪姬次之,树马齿苋最高。三者对Cd的耐性表现为含羞草白雪姬树马齿苋。3种观赏植物对Cd均具有较强累积能力,在土壤Cd含量为100mg.kg-1时,三者根和地上部分的Cd累积浓度均高于100mg.kg-1。且对Cd积累能力为树马齿苋含羞草白雪姬。含羞草、白雪姬和树马齿苋在土壤Cd污染的治理中有一定的应用价值。     

Silver tolerance and accumulation in yeasts

Summary Debaryomyces hansenii (NCYC 459 and strain 75-21),Candida albicans (3153A),Saccharomyces cerevisiae (X2180-1B),Rhodotorula rubra (NCYC 797) andAureobasidium pullulans (IMI 45533 and ATCC 42371) were grown on solid medium supplemented with varying concentrations of AgNO₃. Although Ag⁺ is highly toxic towards yeasts, growth on solid media was still possible at Ag concentrations of 1–2 mM. Further subculture on higher Ag concentrations (up to 5 mM) resulted in elevated tolerance. The extent of Ag tolerance depended on whether Ag-containing plates were exposed to light prior to inoculation since light-mediated reduction of Ag⁺ to Ag⁰ resulted in the production of a less toxic silver species. Experimental organisms exhibited blackening of colonies and the surrounding agar during growth on AgNO₃-containing medium especially at the highest Ag concentrations tested. All organisms accumulated Ag from the medium; electron microscopy revealed that silver was deposited as electron-dense granules in and around cell walls and in the external medium. X-ray microprobe analysis indicated that these granules were metallic Ag⁰ although AgCl was also present in some organisms. Volatile and non-volatile reducing compounds were produced by several test organisms which presumably effected Ag⁺ reduction to Ag⁰.     

工业酵母抗逆机理研究进展

工业酵母利用木质纤维素等生物质资源发酵生产醇、酮、醛、酸等各种化合物,是解决人类面临的不可再生资源和能源危机的重要途径,这激发了人们对木质纤维素水解液为原料和环保节能型浓醪发酵技术的极度关注。然而高浓度底物、产物、渗透压、木质纤维素水解液中抑制性物质、发酵过程温度的提高均会抑制微生物生长代谢及发酵性能,这是发酵行业"瓶颈"问题。本文简述了渗透压、温度及抑制性物质对酵母细胞生长的危害,并从胞内稳态平衡、分子水平等方面着重叙述工业酵母对渗透压、温度及抑制性物质的抗逆机制研究进展。     

Increase in antioxidant enzyme activity,stress tolerance and biocontrol efficacy of Pichia kudriavzevii with the transition from a yeast-like to biofilm morphology

Morphological change, such as from yeast-like to biofilm, has been recently considered to be involved in the mode of action of some antagonistic yeasts used as postharvest biocontrol agents. In the present study, the biocontrol yeast, Pichia kudriavzevii, reversibly shifted from a yeast-like morphology on yeast peptone dextrose (YPD) medium with 2% agar to a biofilm morphology on YPD with 0.3% agar. The tolerance of P. kudriavzevii to heat and oxidative stresses, as well as the biocontrol efficacy against postharvest diseases on pear fruit, increased significantly from the yeast-like form to the biofilm form. The activity of antioxidant enzymes, including catalase and superoxidase dismutase, in the biofilm form was also significantly higher. The elevated activity of antioxidant enzymes was associated with less protein and lipid oxidation in the biofilm form, compared to the yeast-like form, under heat and oxidative stresses. These results suggest that activation of antioxidant system with the morphology shift contributes to the enhancement of abiotic stress tolerance and biocontrol performance of P. kudriavzevii. These findings provide new information on the biology of yeast antagonists that is essential for their potential application and development.     

Phytase-active yeasts from grain-based food and beer

Aims: To screen yeast strains isolated from grain‐based food and beer for phytase activity to identify high phytase‐active strains. Methods and Results: The screening of phytase‐positive strains was carried out at conditions optimal for leavening of bread dough (pH 5·5 and 30°C), in order to identify strains that could be used for the baking industry. Two growth‐based tests were used for the initial testing of phytase‐active strains. Tested strains belonged to six species: Saccharomyces cerevisiae, Saccharomyces pastorianus, Saccharomyces bayanus, Kazachstania exigua (former name Saccharomyces exiguus), Candida krusei (teleomorph Issachenkia orientalis) and Arxula adeninivorans. On the basis of initial testing results, 14 strains were selected for the further determination of extracellular and intracellular (cytoplasmic and/or cell‐wall bound) phytase activities. The most prominent strains for extracellular phytase production were found to be S. pastorianus KVL008 (a lager beer strain), followed by S. cerevisiae KVL015 (an ale beer strain) and C. krusei P2 (isolated from sorghum beer). Intracellular phytase activities were relatively low in all tested strains. Conclusions: Herein, for the first time, beer‐related strains of S. pastorianus and S. cerevisiae are reported as phytase‐positive strains. Significance and Impact of the Study: The high level of extracellular phytase activity by the strains mentioned previously suggests them to be strains for the production of wholemeal bread with high content of bioavailable minerals.     

酵母2-苯乙醇耐受性的研究进展

2-苯乙醇(2-phenylethanol, 2-PE)是一种可食用且有玫瑰香味的高级芳香醇,常用于食品、化妆品和药品行业。由于物理和化学法制备2-PE得率低,不适用于工业生产。而作为单细胞真核微生物的酵母具有高效合成“天然” 2-PE的潜力,因此酵母作为底盘微生物合成2-PE的策略深受研究者青睐。然而,在酵母进行2-PE发酵过程中不免会受到2-PE毒害作用影响。因此,亟须研究酵母耐受2-PE的机制为生产实际提供理论基础,这也有助于选育具有较高2-PE耐受性的酵母菌株。本文综述了酵母2-PE耐受性的研究进展,从酵母2-PE合成途径、2-PE耐受性机理等方面进行阐述,主要说明提升酵母2-PE耐受性的方法。掌握酵母2-PE耐受机制,最终提升酵母2-PE产量及转化效率是今后研究的重中之重。     

Stress tolerance of pressure-shocked Saccharomyces cerevisiae

Pressure shock treatment induced synthesis of heat shock protein (hsp104) and tolerance against various stresses such as high temperature, high pressure and high concentration of ethanol in Saccharomyces cerevisiae. The optimum pressures that induced maximal tolerance against these stresses were in the range of 50–75 MPa and depended on the type of stress. However, pressure shock did not stimulate trehalose production in the cells. © Rapid Science Ltd. 1998     

Inferring ethanol tolerance of Saccharomyces and non-Saccharomyces yeasts by progressive inactivation

The kinetics of cell inactivation in the presence of ethanol at 20, 22.5% and 25% (v/v), was measured by progressive sampling and viable counting, and used as an inference of the ethanol resistance status of five non-Saccharomyces strains and one strain of Saccharomyces cerevisiae. The capacity of standard inocula of the same strains to establish growth at increasing initial ethanol concentrations was employed as a comparison. The effect of various different pre-culture conditions on the ethanol resistance of the 6 strains was analysed by the cell inactivation method and by the cell growth method. Exposing cells to 25% (v/v) ethanol for 4 min enabled the differentiation of the yeasts in terms of their resistance to ethanol. The results suggest that the two methods are generally concordant and that the cell inactivation method can, thus, be used to infer ethanol resistance of yeast strains.     

A putative novel role for plant defensins: a defensin from the zinc hyper-accumulating plant, Arabidopsis halleri, confers zinc tolerance

The metal tolerance of metal hyper-accumulating plants is a poorly understood mechanism. In order to unravel the molecular basis of zinc (Zn) tolerance in the Zn hyper-accumulating plant Arabidopsis halleri ssp. halleri, we carried out a functional screening of an A. halleri cDNA library in the yeast Saccharomyces cerevisiae to search for genes conferring Zn tolerance to yeast cells. The screening revealed four A. halleri defensin genes (AhPDFs), which induced Zn but not cadmium (Cd) tolerance in yeast. The expression of AhPDF1.1 under the control of the 35S promoter in A. thaliana made the transgenic plants more tolerant to Zn than wild-type plants, but did not change the tolerance to Cd, copper (Cu), cobalt (Co), iron (Fe) or sodium (Na). Thus, AhPDF1.1 is able to confer Zn tolerance both to yeast and plants. In A. halleri, defensins are constitutively accumulated at a higher level in shoots than in A. thaliana. A. halleri defensin pools are Zn-responsive, both at the mRNA and protein levels. In A. thaliana, some but not all defensin genes are induced by ZnCl2 treatment, and these genes are not induced by NaCl treatment. Defensins, found in a very large number of organisms, are known to be involved in the innate immune system but have never been found to play any role in metal physiology. Our results support the proposition that defensins could be involved in Zn tolerance in A. halleri, and that a role for plant defensins in metal physiology should be considered.