共查询到20条相似文献,搜索用时 0 毫秒
1.
2.
In this study we proposed a method for isolation of Est3p modified with various affinity tags, which is applicable for structural and functional studies, and investigated homo- and heterodimer formation with various recombinant forms of Est3p. 相似文献
3.
Transglutaminase-like activity participates in cell wall biogenesis in <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> 总被引:1,自引:0,他引:1
Transglutaminases (TGases) catalyze the cross-linking between protein molecules by formation of an amide bond between γ-carboxyamide
group of glutamine and the ε-amine group of lysine under deamination of glutamine. We have demonstrated the participation
of transglutaminase-like activity in the isolated cell walls and in the process of cell wall regeneration in protoplasts of
the yeast Saccharomyces cerevisiae. A radioactive TGase substrate [3H]putrescine was incorporated into the isolated cell walls and into the TCA-insoluble fraction in regenerating protoplasts.
The incorporation was increased by adding exogenous artificial substrate of TGase N,N’-dimethylcasein and was inhibited by
TGase inhibitor cystamine and/or EDTA. These results suggest the existence of a TGase-type reaction involved in the formation
of covalent cross-links between glycoprotein molecules during cell wall construction in S. cerevisiae. 相似文献
4.
O. A. Esakova L. E. Meshalkina G. A. Kochetov R. Golbik 《Biochemistry. Biokhimii?a》2009,74(11):1234-1238
Pyruvate derivatives halogenated at C3 were shown to be donor substrates in the transketolase reaction. No drastic differences
between the derivatives were observed in the value of the catalytic constant, whereas the Michaelis constant increased in
the following order: Br-pyruvate < Cl-pyruvate < Cl2-pyruvate < F-pyruvate < Br2-pyruvate. The presence of the halogenated pyruvate derivatives increased the affinity of apotransketolase for the coenzyme;
of note, the extent of this effect was equal with both of the active centers of the enzyme. In contrast, the presence of any
other substrate known to date, including hydroxypyruvate (i.e. pyruvate hydroxylated at C3), induced nonequivalence of the
active centers in that they differed in the extent to which the affinity for the coenzyme increased. Consequently, the β-hydroxyl
of dihydroxyethylthiamine diphosphate (an intermediate of the transketolase reaction) played an important role in the phenomenon
of non-equivalence of the active centers associated with the coenzyme binding. The fundamental possibility was demonstrated
of using halogenated pyruvate derivatives as donors of the halogen-hydroxyethyl group in organic synthesis of halogenated
carbohydrates involving transketolase. 相似文献
5.
Tatina T. Todorova Ventsislava Y. Petrova Stéphane Vuilleumier Anna V. Kujumdzieva 《Archives of microbiology》2009,191(11):837-845
Growth of Saccharomyces cerevisiae
ure2Δ mutant strain was investigated in the presence of diverse oxidant compounds. The inability of the strain to grow on a medium
supplemented with H2O2 was confirmed and a relationship between diminishing levels of glutathione (GSH) and peroxide sensitivity was established.
Data for the lack of significant effect of URE2 disruption on the cellular growth in the presence of paraquat and menadione were obtained. The possible role of Ure2p in
acquiring sensitivity to oxidative stress by means of its regulatory role in the GATA signal transduction pathway was discussed.
It was suggested that the susceptibility of ure2Δ mutant to the exogenous hydrogen peroxide can result from increased GSH degradation due to the deregulated localization of
the γ-glutamyl transpeptidase activating factors Gln3/Gat1. The important role of Ure2p in in vivo glutathione-mediated reactive
oxygen species (ROS) scavenging was shown by measuring the activity of antioxidant enzymes glutathione peroxidase, superoxide
dismutase (SOD) and catalase in an URE2 disrupted strain. A time-dependent increase in SOD and catalase activity was observed. More importantly, it was shown that
the ure2 mutation could cause significant disturbance in cellular oxidant balance and increased ROS level. 相似文献
6.
7.
Junmei Ding Xiaowei Huang Lemin Zhang Na Zhao Dongmei Yang Keqin Zhang 《Applied microbiology and biotechnology》2009,85(2):253-263
Eukaryotic cells have developed diverse strategies to combat the harmful effects of a variety of stress conditions. In the
model yeast Saccharomyces cerevisiae, the increased concentration of ethanol, as the primary fermentation product, will influence the membrane fluidity and be
toxic to membrane proteins, leading to cell growth inhibition and even death. Though little is known about the complex signal
network responsible for alcohol stress responses in yeast cells, several mechanisms have been reported to be associated with
this process, including changes in gene expression, in membrane composition, and increases in chaperone proteins that help
stabilize other denatured proteins. Here, we review the recent progresses in our understanding of ethanol resistance and stress
responses in yeast. 相似文献
8.
POL LHOAS 《Nature: New biology》1972,236(64):86-87
IN contrast to bacteriophages which are strictly host-specific, double stranded RNA fungal viruses are shown to be able to infect a different host genus and so bear some similarity to some viruses of higher plants. The technique of infecting yeasts with viruses from filamentous fungi and the morphological criterion by which infection is detected are described here. 相似文献
9.
I. A. Sevostyanova V. A. Selivanov V. A. Yurshev O. N. Solovjeva S. V. Zabrodskaya G. A. Kochetov 《Biochemistry. Biokhimii?a》2009,74(7):789-792
Catalytic activity of two active sites of transketolase and their affinity towards the substrates (xylulose-5-phosphate and ribose-5-phosphate) has been studied in the presence of Ca2+ and Mg2+. In the presence of Ca2+, the active sites exhibit negative cooperativity in binding both xylulose-5-phosphate (donor substrate) and ribose-5-phosphate (acceptor substrate) and positive cooperativity in the catalytic transformation of the substrates. In the presence of Mg2+, nonequivalence of the active sites is not observed. 相似文献
10.
11.
Kang Hee Nam Hwa Jee Chung Eo Jin Jeon Mi Kyung Park Yong Hyeon Yim Jang Ryol Liu Jeong Ho Park 《Journal of Plant Biology》2007,50(3):315-320
Strictosidine is a key intermediate in the biosynthesis of the terpenoid indole alkaloid (T1A) pathway. It results from a
condensation reaction, catalyzed by strictosidine synthase (STR), between tryptamine and secologanin. We have now developed
a useful method, based on enzyme-assisted synthesis, to produce strictosidine. Our procedure utilizes leaf extracts from Japanese
honeysuckleLonicera japonica Thunb. as a secologanin source. In these experiments, an enzyme extract was prepared from transgenic yeastSaccharomyces cerevisiae that expresses theCatharanthus roseus STR (CrSTR) coding region. Strictosidine was then isolated with a 38% yield based on the initial amount of tryptamine in the
enzymatic reaction. 相似文献
12.
Jihee Yoon Jae-Min Park Seung-Ki Jung Keun-Young Kim Yang-Hoon Kim Jiho Min 《Current microbiology》2009,59(1):48-52
The antimicrobial activity of lysosomes, a cell organelle, against a range of test microorganisms was examined in this study.
The lysosomes isolated from Saccharomyces cerevisiae showed antimicrobial activity to Escherichia coli that positively correlated with the pH of the phosphate buffer as a dissolving solvent. The lysosomes from S. cerevisiae exhibited optimal activity at a concentration of 40%, at pH 4.0 of phosphate buffer, and at broad range temperature, except
of over 50°C. It was also found that the lysosomes have antimicrobial activity against seven different microorganisms including
E. coli. In addition, S. cerevisiae were exposed by a treatment with H2O2 and lysosomes were isolated from H2O2 exposed S. cerevisiae. We found that fluorescent intensities of each isolated lysosomes were increased depending on the increment of treated H2O2 concentration, and the lysosomes from 20 mM H2O2 treated S. cerevisiae showed higher antimicrobial activity than those from normal S. cerevisiae. Therefore, it suggests that lysosomes isolated from S. cerevisiae can be used as an antimicrobial agent. In addition, lysosomes activated by H2O2 enhanced its antimicrobial activity. 相似文献
13.
14.
There are three most important bacterial causative agents of serious infections that could be misused for warfare purposes:
Bacillus anthracis (the causative agent of anthrax) is the most frequently mentioned one; however, Fracisella tularensis (causing tularemia) and Yersinia pestis (the causative agent of plague) are further bacterial agents enlisted by Centers for Disease Control and Prevention into the category A of potential biological weapons. This review intends to summarize basic information about these bacterial
agents. Military aspects of their pathogenesis and the detection techniques suitable for field use are discussed. 相似文献
15.
An in vitro method for propagation of Holarrhena antidysenterica Wall. has been developed using nodal explants from mature trees growing in the field. Irrespective of concentrations and
combinations of growth regulators used, the axillary and terminal buds sprouted and elongated when inoculated on Murashige
and Skoog (MS) medium. The highest numbers of shoots were formed when sprouted shoots were subcultured from MS basal medium
onto MS medium containing 2 mg dm−3 N6-benzyladenine (BA) and 0.5 mg dm−3 α-naphthalene acetic acid (NAA). The shoot number further increased upon subculture on MS medium containing 0.5 mg dm−3 BA. By repeated sub-culturing of shoots derived from nodal axillary buds, a high frequency multiplication rate was established.
The elongated shoots were excised and rooted in auxin free MS basal medium. Ex vitro rooting of in vitro formed shoots was achieved upon dipping the microshoots for 2 min in 2 mg dm−3 of indole-3-butyric acid solution. Successful field establishment and high (80–90 %) survival of plants was observed. 相似文献
16.
An experiment was taken up to find out possibilities of manipulating the in vitro flowering in moth bean. Abscisic acid (ABA) and proline both alone and in combination influenced days to flower induction,
number of flowers per plant, number of pods per plant and seeds per pod. Frequency of flowering plants approached 100 % at
1 and 3 μM ABA and 800 μM proline. The range of flowering period (3 to 23.6 d) has also been influenced by various treatments. 相似文献
17.
The influence of sugars and growth regulators on shoot and root growth of Dactylorhiza species was studied under in vitro conditions. The seedling development was stimulated with the application of glucose and sucrose at concentration of 10 g
dm−3 each. The improvement of shoot growth rate and shoot length was enhanced by cytokinins N
6-(2-isopentenyl)adenine or N
6-benzyladenine and their combination with auxin indolebutyric acid (IBA). The root growth rate and root length of seedlings
increased in the presence of IBA and α-naphthaleneacetic acid. Individual Dactylorhiza species showed statistically significant differences in shoot and root development depending on sugar and growth regulator
combinations. 相似文献
18.
19.
20.
Aneesh Kumar Nair Naik Dhiraj Dilip Pandit Sagar Subhash 《Journal of Plant Biology》2007,50(3):374-377
High-frequencyin vitro flowering is reported here fromin vitro regenerated shoots ofin vitro-raised seedlings of rare and endemicCeropegia lawii, Ceropegia maccannii, Ceropegia oculata, andCeropegia sahyadrica, as well as the widely distributedCeropegia bulbosa var.bulbosa andCeropegia hirsuta. In our first set of experiments, the MS medium contained 87 mM sucrose and was supplemented with varying concentrations of
BAP (4.4 to 26.6 μM). For the second set of trials, varying concentrations of sucrose (87 to 233 mM) were tested in MS media
containing a constant 4.4 p.M BAP. Sub-cultured apical as well as axillary buds flowered with similar frequencies after 30
d of incubation. For all six species, the highest percentage of flowering shoots was obtained with either 26.6 μM BAP or 175
mM sucrose. Although smaller in size, theirin vitro flowers were morphologically comparable within wVo-derived flowers. Variations among species were noted for the number of flower buds per shoot and the percentage of flower
formation. Because all six species showed similar responses in both experiments, we can suggest that this protocol is applicable
across the wide range ofCeropegia species. 相似文献