共查询到20条相似文献,搜索用时 15 毫秒
1.
M. J. Beker J. E. Blumbergs E. J. Ventina A. I. Rapoport 《Applied microbiology and biotechnology》1984,19(5):347-352
Summary This paper describes the characteristics of the structural and functional organization of cellular membranes rehydrated after dehydration of the yeast Saccharomyces cerevisiae. It was noted that dehydration and subsequent rehydration of yeast cells causes a considerable increase of cytoplasmic membrane permeability. Addition of CaCl2, glucose and polyethyleneglycol to the rehydration medium caused a decrease in cell permeability, assessed as the losses of potassium ions, nucleotides, as well as the total losses of intracellular compounds. KCl had a positive effect only at concentrations above 10%. Yeast cells, dried to residual moisture lower than 20%, showed a decrease in membrane permeability as temperatures of the rehydration medium increased up to 38°–43°C. Upon reactivation of viable dehydrated cells in a nutrient medium, a reparation of the structural damages of various intracellular membranes takes place. It was established that at cell dehydration to residual moistures of 8%–12% all the free and a part of bound water is evaporated from cells. 相似文献
2.
We have found that incubation in lactose solutions (0.75 M) of yeast culture Saccharomyces cerevisiae sensitive to dehydration damage increased the stability of the cells during dehydration. Simultaneously with this increase
in viability, a decrease in plasma membrane permeability during rehydration was seen. Using Fourier transform infrared spectroscopy
to measure lipid phase transitions, we observed that the lactose treatment depressed the membrane phospholipid phase transition
temperature in a sensitive culture of dry yeast. As a result, it leads to the decrease in the damages of molecular organization
of membranes during rehydration of dry yeast cells, thus reducing leakage from the cells. 相似文献
3.
Rikhvanov EG Varakina NN Rusaleva TM Rachenko EI Voinikov VK 《Current microbiology》2002,45(6):0394-0399
The effect of sodium azide in heat shock-induced cell death was studied in Debaryomyces vanrijiae, Candida albicans, and Saccharomyces cerevisiae yeasts. The results presented demonstrate that the azide addition induced a drastic decrease in the thermotolerance of glucose-grown
D. vanrijiae. In contrast, glucose-grown S. cerevisiae and C. albicans cells treated with NaN3 became more resistant to heat shock than control cells. Nevertheless, in galactose medium the decrease of thermotolerance
of S. cerevisiae and C. albicans cells was observed in the presence of sodium azide. It was suggested that the decreasing effect of sodium azide on thermotolerance
takes place only when the yeast cell is incapable of using fermentation for ATP synthesis and obtains energy via oxidative
phosphorylation.
Received: 27 December 2001 / Accepted: 27 February 2002 相似文献
4.
Production of the Artemisinin Precursor Amorpha-4,11-diene by Engineered Saccharomyces cerevisiae 总被引:5,自引:0,他引:5
Lindahl AL Olsson ME Mercke P Tollbom O Schelin J Brodelius M Brodelius PE 《Biotechnology letters》2006,28(8):571-580
The gene encoding for amorpha-4,11-diene synthase from Artemisia annua was transformed into yeast Saccharomyces cerevisiae in two fundamentally different ways. First, the gene was subcloned into the galactose-inducible, high-copy number yeast expression
vector pYeDP60 and used to transform the Saccharomyces cerevisiae strain CEN·PK113-5D. Secondly, amorpha-4,11-diene synthase gene, regulated by the same promoter, was introduced into the
yeast genome by homologous recombination. In protein extracts from galactose-induced yeast cells, a higher activity was observed
for yeast expressing the enzyme from the plasmid. The genome-transformed yeast grows at the same rate as wild-type yeast while
plasmid-carrying yeast grows somewhat slower than the wild-type yeast. The plasmid and genome-transformed yeasts produced
600 and 100 μg/l of the artemisinin precursor amorpha-4,11-diene, respectively, during 16-days’ batch cultivation.
Revisions requested 14 November 2005; Revisions received 17 January 2006 相似文献
5.
I. L. Krallish B. E. Damberga M. J. Beker 《Applied microbiology and biotechnology》1986,23(6):482-486
Summary It has been shown that dehydration markedly affects the activity of a number of enzymes connected with energy metabolism in
the yeastSaccharomyces cerevisiae. Independently of the drying method used, there was found to be an inverse relationship between the activity of mitochondrial
enzymes — NADH-dehydrogenase (EC 1.6.2.1), succinate dehydrogenase (EC 1.3.99.1) and cytochrome C oxidase (EC 1.9.3.1) - and
the viability of yeast cells at the stationary growth phase. Dehydration led to an increase in activity only in exogenous
NADH-dehydrogenase compared with activity in the initial compressed yeast.
On the basis of alcohol dehydrogenase (EC 1.1.1.1) and catalase (EC 1.11.1.6) as examples, an ambivalent effect of the dehydration
process on the activity of cytoplasmic enzymes has been demonstrated.
The results obtained lead to the conclusion that the activity of individual electron-transport enzymes in yeastSaccharomyces cerevisiae is a sufficiently sensitive to be used as an indicator of the physiological state and to monitor a microbial biomass dehydration
procedure. 相似文献
6.
Rivera-Molina Félix E. González-Crespo Sahily Cruz Yasdet Maldonado-De la Ortiz-Betancourt José M. Rodríguez-Medina José R. 《World journal of microbiology & biotechnology》2006,22(3):255-260
Summary Nikkomycin Z (NZ) is a competitive inhibitor of chitin synthase III in the yeast Saccharomyces cerevisiae. Myosin type II-deficient yeast strains (myo1) display a dramatic reduction in growth when chitin synthase III activity is inhibited by NZ, supporting the contention that
actomyosin motility plays an important role in maintaining cell wall integrity. A proposed inhibitor of cortical actin polymerization
in vitro, 2,3-butanedione monoxime (BDM), also inhibits growth of wild-type yeast strains at a concentration of 20 mM. In this study,
we assayed for potential in vivo interplay between BDM-sensitive cell functions and cell wall chitin synthesis by testing for increased sensitivity to NZ
during co-treatment with BDM at sub-inhibitory concentrations. Our results show that BDM can increase the sensitivity of yeast
cells to Nikkomycin Z. 相似文献
7.
J. M. S. Cabral J. M. Novais J. F. Kennedy 《Applied microbiology and biotechnology》1986,23(3-4):157-162
Summary Whole cells of Saccharomyces bayanus, Saccharomyces cerevisiae and Zymomonas mobilis were immobilized by chelation/metal-link processes onto porous inorganic carriers. The immobilized yeast cells displayed much higher sucrose hydrolyzing activities (90–517 U/g) than the bacterial, Z. mobilis, cells (0.76–1.65 U/g). The yeast cells chelated on hydrous metal oxide derivative of pumice stone presented higher initial -d-fructofuranosidase (invertase, EC 3.2.1.26) activity (161–517 U/g) than on other derivatives (90–201 U/g). The introduction of an organic bridge between the cells and the metal activator led to a decrease of the initial activity of the immobilized cells, however S. cerevisiae cells immobilized on the carbonyl derivative of titanium (IV) activated pumice stone, by covalent linkage, displayed a very stable behaviour, which in continuous operation at 30° C show only a slightly decrease on invertase activity for a two month period (half-life=470 days). The continuous hydrolysis of a 2% w/v sucrose solution at 30° C in an immobilized S. cerevisiae packed bed reactor was described by a simple kinetic model developed by the authors (Cabral et al., 1984a), which can also be used to predict the enzyme activity of the immobilized cells from conversion degree data. 相似文献
8.
P. B. Zikmanis S. I. Auzane L. P. Auzina M. V. Margevicha M. J. Beker 《Applied microbiology and biotechnology》1985,22(4):265-267
Summary An investigation was made of changes in ergosterol content of the yeast Saccharomyces cerevisiae upon drying and subsequent rehydration. It was established that drying increases, but rehydration diminishes ergosterol content in yeasts. A statistically reliable multiple correlation was established between the resistance of population to drying, decrease of ergosterol content and a diminishing degree of fatty acid unsaturation during dehydration of dry yeasts. 相似文献
9.
《Electromagnetic biology and medicine》2013,32(3):363-369
Electroporative drug delivery (electroloading of cells) takes place effectively by inserting electrodes mediating strong electric pulses. Another possibility is the disturbance of lipid bilayer structures by weak pulsating electromagnetically induced currents (PEMIC) produced by Helmholtz coils. In yeast cells (Saccharomyces cerevisiae) the enhancement of drug (sensitizer) transport through cell membranes by PEMIC results in an increased photodynamic cell killing. Depending on the magnetic flux, a window of 25% killing rate, caused by the photodynamic effect, could be observed at approximately 8 mT with a frequency of 50 Hz. 相似文献
10.
Cloning of Arabidopsis thaliana phosphatidylinositol synthase and functional expression in the yeast pis mutant 总被引:1,自引:0,他引:1
It is believed that phosphatidylinositol (PI) metabolism plays a central role in signalling pathways in both animals and higher plants. PI is synthesized from CDP-diacylglycerol (CDP-DG) and myo-inositol by phosphatidylinositol synthase (PI synthase, EC 2.7.8.11). Here we report the identification of a plant cDNA (AtPIS1) encoding a 26 kDa PI synthase from Arabidopsis thaliana. The plant enzyme as deduced from its cDNA sequence shares 35–41% identical amino acids with PI synthases from Saccharomyces cerevisiae and mammals. AtPIS1 functionally complements a mutant of S. cerevisiae with a lesion in PI synthase, and recombinant AtPIS1 protein present in yeast membranes strongly depends on the two principal substrates, myo-inositol and CDP-DG, and requires Mg2+ ions for full activity. 相似文献
11.
Proteolytic stability of recombinant human serum albumin secreted in the yeast Saccharomyces cerevisiae 总被引:4,自引:0,他引:4
Kang HA Choi ES Hong WK Kim JY Ko SM Sohn JH Rhee SK 《Applied microbiology and biotechnology》2000,53(5):575-582
In order to direct the persistent expression of recombinant human serum albumin (HSA) from the GAL10 promoter in the yeast Saccharomyces cerevisiae, we carried out periodic feeding of galactose during shake-flask cultures. Unexpectedly, the recombinant protein secreted
was observed to undergo rapid degradation, which was apparently accelerated by carbon-source feeding. The extracellular degradation
of HSA occurred even in the strain deficient in the major vacuolar proteases PrA and PrB, and in the strain lacking the acidic
protease Yap3p (involved in the generation of HSA-truncated fragments). Interestingly, the degradation correlated closely
with the acidification of extracellular pH and thus was significantly overcome either by buffering the culture medium above
pH 5.0 or by adding amino acid-rich supplements to the culture medium, which could prevent the acidification of medium pH
during cultivation. Addition of arginine or ammonium salt also substantially minimized the degradation of HSA, even without
buffering. The extracellular degradation activity was not detected in the cell-free culture supernatant but was found to be
associated with intact cells. The results of the present study strongly suggest that the HSA secreted in S. cerevisiae is highly susceptible to the pH-dependent proteolysis mediated by cell-bound protease(s) whose activity and expression are
greatly affected by the composition of the medium.
Received: 23 August 1999 / Received revision: 8 November 1999 / Accepted: 12 December 1999 相似文献
12.
Hydrophilins are a group of proteins that are present in all organisms and that have been defined as being highly hydrophilic and rich in glycine. They are assumed to play important roles in cellular dehydration tolerance. There are 12 genes in the yeast Saccharomyces cerevisiae that encode hydrophilins and most of these genes are stress responsive. However, the functional role of yeast hydrophilins, especially in desiccation and freezing tolerance, is largely unknown. Here, we selected six candidate hydrophilins for further analysis. All six proteins were predicted to be intrinsically disordered, i.e. to have no stable structure in solution. The contribution of these proteins to the desiccation and freezing tolerance of yeast was investigated in the respective knock-out strains. Only the disruption of the genes YJL144W and YMR175W (SIP18) resulted in significantly reduced desiccation tolerance, while none of the strains was affected in its freezing tolerance under our experimental conditions. Complementation experiments showed that yeast cells overexpressing these two genes were both more desiccation and freezing tolerant, confirming the role of these two hydrophilins in yeast dehydration stress tolerance. 相似文献
13.
Expression and activation of the vacuolar processing enzyme in Saccharomyces cerevisiae 总被引:1,自引:0,他引:1
Nagako Hiraiwa Mikio Nishimura Ikuko Hara-Nishimura 《The Plant journal : for cell and molecular biology》1997,12(4):819-829
Vacuolar processing enzymes (VPEs) are cysteine proteinases responsible for maturation of various vacuolar proteins in plants. A larger precursor to VPE synthesized on rough endoplasmic reticulum is converted to an active enzyme in the vacuoles. In this study, a precursor to castor bean VPE was expressed in a pep4 strain of the yeast Saccharomyces cerevisiae to examine the mechanism of activation of VPE. Two VPE proteins of 59 and 46 kDa were detected in the vacuoles of the transformant. They were glycosylated in the yeast cells, although VPE is not glycosylated in plant cells in spite of the presence of two N-linked glycosylation sites. During the growth of the transformant, the level of the 59 kDa VPE increased slightly until a rapid decrease occurred after 9 h. By contrast, the 46 kDa VPE appeared simultaneously with the disappearance of the 59 kDa VPE. Vacuolar processing activity increased with the accumulation of the 46 kDa VPE, but not of the 59 kDa VPE. The specific activity of the 46 kDa VPE was at a similar level to that of VPE in plant cells. The 46 kDa VPE instead of proteinase A mediated the conversion of procarboxypeptidase Y to the mature form. This indicates that proteinase A responsible for maturation of yeast vacuolar proteins can be replaced functionally by plant VPE. These findings suggest that an inactive VPE precursor synthesized on the endoplasmic reticulum is transported to the vacuoles in the yeast cells and then processed to make an active VPE by self-catalytic proteolysis within the vacuoles. 相似文献
14.
Antioxidant defense parameters as predictive biomarkers for fermentative capacity of active dried wine yeast
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Esther Gamero‐Sandemetrio Rocío Gómez‐Pastor Emilia Matallana 《Biotechnology journal》2014,9(8):1055-1064
The production of active dried yeast (ADY) is a common practice in industry for the maintenance of yeast starters and as a means of long term storage. The process, however, causes multiple cell injuries, with oxidative damage being one of the most important stresses. Consequentially, dehydration tolerance is a highly appreciated property in yeast for ADY production. In this study we analyzed the cellular redox environment in three Saccharomyces cerevisiae wine strains, which show markedly different fermentative capacities after dehydration. To measure/quantify the effect of dehydration on the S. cerevisiae strains, we used: (i) fluorescent probes; (ii) antioxidant enzyme activities; (ii) intracellular damage; (iii) antioxidant metabolites; and (iv) gene expression, to select a minimal set of biochemical parameters capable of predicting desiccation tolerance in wine yeasts. Our results show that naturally enhanced antioxidant defenses prevent oxidative damage after wine yeast biomass dehydration and improve fermentative capacity. Based on these results we chose four easily assayable parameters/biomarkers for the selection of industrial yeast strains of interest for ADY production: trehalose and glutathione levels, and glutathione reductase and catalase enzymatic activities. Yeast strains selected in accordance with this process display high levels of trehalose, low levels of oxidized glutathione, a high induction of glutathione reductase activity, as well as a high basal level and sufficient induction of catalase activity, which are properties inherent in superior ADY strains. 相似文献
15.
D. M. Bui I. Kunze C. Horstmann T. Schmidt K. D. Breunig G. Kunze 《Applied microbiology and biotechnology》1996,45(1-2):102-106
The glucoamylase gene of the yeast Arxula adeninivorans was expressed in Kluyveromyces lactis by using the GAP promoter from Saccharomyces cerevisiae and a multicopy plasmid vector. The transformants secreted 90.1% of the synthesized glucoamylase into the culture medium.
The secreted glucoamylase activities are about 20 times higher in comparison to those of Saccharomyces cerevisiae transformants using the same promoter. Secreted glucoamylase possesses identical N-terminal amino acid sequences to those
secreted by A. adeninivorans showing that cleavage of the N-terminal signal peptide takes place at the same site. Biochemical characteristics of glucoamylase
expressed by K. lactis and A. adeninivorans are very similar.
Received: 12 June 1995/Received revision: 17 July 1995/Accepted: 26 July 1995 相似文献
16.
Aims: Dammarenediol production by an engineered yeast Saccharomyces cerevisiae was investigated. Methods and Results: A dammarenediol‐producing engineered yeast was constructed by heterologous expression of the dammarenediol synthase gene from Panax ginseng hairy roots through RT‐PCR. Fermentation was carried out in a 5‐L GRJY‐bioreactor with an inoculum size of 1% v/v at 30°C. Dammarenediol detection was performed with silica gel chromatography and HPLC. Determination of dammarenediol synthase activity subcellular distribution was carried out by surveying the enzyme activity in microsomes, lipid particles and total yeast homogenate. When cultured under aerobic conditions, the engineered yeast could produce dammarenediol up to 250 μg l?1. However, when an anaerobic shift strategy was employed, dammarenediol accumulated at a level as twice as that under aerobic condition. The dammarenediol synthase and dammarenediol were mainly localized in lipid particles. Conclusions: Dammarenediol could be heterologously produced in engineered yeast. The heterologously expressed dammarenediol synthase is mainly localized in lipid particles. Anaerobic shift strategy could enhance the dammarenediol level in the engineered yeast. Significance and Impact of the Study: This study showed that the high‐value plant product dammarenediol could be produced by heterologous expression of the according gene in yeast. Furthermore, the anaerobic shift strategy could be potentially applied in oxidosqualene‐derived compounds production in yeast. Here, the information about subcellular distribution of heterologously expressed dammarenediol synthase in the engineered yeast was also provided. 相似文献
17.
【目的】利用酿酒酵母表达系统,通过乙醇脱氢酶启动子异源表达细菌源的铁载体合成蛋白PchE,并与来源于枯草芽孢杆菌的泛酰化酶Sfp同宿主共表达,探索真核表达体系表达具有生化活性的细菌源蛋白。【方法】从大肠杆菌BAP1染色体上扩增sfp基因,将pchE基因及串联的pchE与sfp基因分别构建到酵母-大肠杆菌穿梭质粒pXW55中,各自转化酿酒酵母BJ5464-npg A表达,经过亲和层析和离子交换层析纯化蛋白,利用HPLC检测细菌源与酵母源表达的PchE在体外重构生化反应中的催化活性。【结果】利用酿酒酵母表达系统可以获得高纯度的原核蛋白PchE。真菌源的泛酰化基因NpgA和细菌源的Sfp,均可泛酰化修饰PchE,合成中间产物HPT-Cys。【结论】在酿酒酵母Saccharomyces cerevisiae BJ5464-npgA表达系统中,首次证明真菌源的泛酰化基因NpgA和细菌源的Sfp,均可泛酰化修饰细菌源的非核糖体肽合酶。比较酵母和细菌宿主的目标蛋白表达,证明酵母表达的巨大蛋白PchE的纯度更高,非特异性条带减少,推测酵母宿主可能更适合表达纯化功能性的巨型蛋白质。 相似文献
18.
Muramatsu M Ohto C Obata S Sakuradani E Shimizu S 《Applied microbiology and biotechnology》2008,80(4):589-595
Squalene synthase inhibitors significantly accelerate the production of farnesol by various microorganisms. However, farnesol
production by Saccharomyces cerevisiae ATCC 64031, in which the squalene synthase gene is deleted, was not affected by the inhibitors, indicating that farnesol
accumulation is enhanced in the absence of squalene synthase activity. The combination of diphenylamine as an inhibitor of
carotenoid biosynthesis and a squalene synthase inhibitor increases geranylgeraniol production by a yeast, Rhodotorula rubra NBRC 0870. An ent-kauren synthase inhibitor also enhances the production of farnesol and geranylgeraniol by a filamentous
fungus, Gibberella fujikuroi NBRC 30336. These results indicate that the inhibition of downstream enzymes from prenyl diphosphate synthase leads to the
production of farnesol and geranylgeraniol. 相似文献
19.
Hélène Cordier Christian Lacombe Francis Karst Thierry Bergès 《Current microbiology》1999,38(5):290-294
The wild-type ERG19 gene of the yeast Saccharomyces cerevisiae encoding mevalonate diphosphate decarboxylase (MVD) and the mutated recessive erg19-34 allele leading to a decrease of sterol production and to a thermosensitive phenotype have been characterized [2]. The mutated
erg19-34 allele bears a single amino acid leucine79-to-proline (L79P) substitution. It was shown that this mutation does not affect
the level of production of the enzyme. We performed a two-hybrid assay to show that the yeast Saccharomyces cerevisiae MVD forms homodimers in vivo and that the single point mutation drastically impairs the oligomerization of the protein, thereby
explaining the deficiency of MVD activity observed in the temperature-sensitive strain.
Received: 2 January 1999 / Accepted: 4 January 1999 相似文献
20.
Mitsuyoshi Ueda Shin-ichi Sanuki Hiroyuki Kawachi Kaori Shimizu Haruyuki Atomi Atsuo Tanaka 《Archives of microbiology》1997,168(1):8-15
Citrate synthase, an essential enzyme of the tricarboxylic acid cycle in mitochondria, was purified from acetate-grown Candida tropicalis. Results from SDS-PAGE and gel filtration showed that this enzyme was a dimer composed of 45-kDa subunits. A citrate synthase
cDNA fragment was amplified by the 5′-RACE method. Nucleotide sequence analysis of this cDNA fragment revealed that the deduced
amino acid sequence contained an extended leader sequence which is suggested to be a mitochondrial targeting signal, as judged
from helical wheel analysis. Using this cDNA probe, one genomic citrate synthase clone was isolated from a yeast λEMBL3 library.
The nucleotide sequence of the gene encoding C. tropicalis citrate synthase, CtCIT, revealed the presence of a 79-bp intron in the N-terminal region. Sequences essential as yeast splicing motifs were present
in this intron. When the CtCIT gene including its intron was introduced into Saccharomyces cerevisiae using the promoter UPR-ICL, citrate synthase activity was highly induced, which strongly indicated that this intron was correctly spliced in S. cerevisiae.
Received: 20 November 1996 / Accepted: 25 February 1997 相似文献