共查询到20条相似文献,搜索用时 15 毫秒
1.
Mg2+ at 3.5 mM increased the tolerance of a self-flocculating fusant of Schizosaccharomyces pombe and Saccharomyces cerevisiae to ethanol. After 9 h of exposure to 20% (v/v) ethanol at 30 °C, all cells died whereas over 50% remained viable for the cells grown with Mg2+. The effect of Mg2+ is closely related to its ability to decrease plasma membrane permeability of cells subjected to ethanol stress. 相似文献
2.
Ana?Lúcia?Kern Diego?Bonatto Johnny?Ferraz?Dias Maria-Lucia?Yoneama Martin?Brendel Jo?o?Antonio?Pêgas?Henriques
Two genes in Saccharomyces cerevisiae, ALR1 and ALR2, encode transmembrane proteins involved in Mg2+ uptake. The present study investigates the phylogenetic relationship of Alr1p/Alr2p with bacterial CorA proteins and some
proteins related to Mg2+influx/efflux transport in mitochondrial and bacterial zinc transporters; including hydrophobic cluster analysis (HCA). The
phylogenetic results indicate that the Alrp sequences of S. cerevisiae share a common carboxy-terminus with proteins related to zinc efflux transport. We also analyse the intracellular metal content
by particle-induced X-ray emission (PIXE) after cell exposure to cadmium. The PIXE analysis of cadmium-exposed ALR mutants and wild-type yeast cells suggests that Alrp has a central role in cell survival in a cadmium-rich environment.
Published online December 2004
Ana Lúcia Kern, Diego Bonatto: Both authors contributed equally to this work. 相似文献
3.
Concentrations of Mg2+, glycine, yeast extract, biotin, acetaldehyde and peptone were optimized by a uniform design process for ethanol production
by Saccharomyces cerevisiae. Using non-linear step-wise regression analysis, a predictive mathematical model was established. Concentrations of Mg2+ and peptone were identified as the critical factors: 50 mM Mg2+ and 1.5% (w/v) peptone in the medium increased the final ethanol titre from 14.2% (v/v) to 17% (v/v) in 48 h. 相似文献
4.
Ethanol-induced changes of CO2 production were compared in three strains ofSaccharomyces cerevisiœ. CaCl2 and MgCl2 exerted protective effects against the action of ethanol. Optimal concentrations ensuring maximum of CO2 production at 10% (V/V) of ethanol under non-growing conditions were 3 mmol/L Ca2+ and 2 mmol/L Mg2+. Yeast growth with and without ethanol addition was stimulated by Mg2+ more than by Ca2+ during fermentation, whereas ethanol production was more efificient when both Ca2+ and Mg2+ were added. 相似文献
5.
Brasser HJ Krijger GC van Meerten TG Wolterbeek HT 《Biological trace element research》2006,112(2):175-189
Silicon (Si, as silicate) is involved in numerous important structure and function roles in a wide range of organisms, including
man. Silicate availability influences metal concentrations within various cell and tissue types, but, as yet, clear mechanisms
for such an influence have been discovered only within the diatoms and sponges. In this study, the influence of silicate on
the intracellular accumulation of metals was investigated in baker's yeast (Saccharomyces cerevisiae). It was found that at concentrations up to 10 mM, silicate did not influence the growth rate of S. cerevisiae within a standard complete medium. However, an 11% growth inhibition was observed when silicate was present at 100 mM. Intracellular metal concentrations were investigated in yeast cultures grown without added silicate (−Si) or with the addition
of 10 mM silicate (+Si). Decreased amounts of Co (52%), Mn (35%), and Fe (20%) were found within +Si-grown yeast cultures as compared
to −Si-grown ones, whereas increased amounts of Mo (56%) and Mg (38%) were found. The amounts of Zn and K were apparently
unaffected by the presence of silicon. +Si enhanced the yeast growth rate for low-Zn2+ medium, but it decreased the growth rate under conditions of a low Mg2+ medium and did not alter the growth rates in high Zn2+ and Co2+ media. +Si doubled the uptake rate of Co2+ but did not influence that of Zn2+. We propose that a possible explanation for these results is that polysilicate formation at the cell wall changes the cell
wall binding capacity for metal ions. The toxicity of silicate was compared to germanium (Ge, as GeO2), a member of the same group of elements as Si (group 14). Hence, Si and Ge are chemically similar, but silicate starts to
polymerize to oligomers above 5 mM, whereas Ge salts remain as monomers at such concentrations. Ge proved to be far more toxic to yeast than Si and no influence
of Si on Ge toxicity was found. We propose that these results relate to differences in cellular uptake. 相似文献
6.
We isolated and characterized a nickel (Ni2+)-resistant mutant (GA1) of Schizosaccharomyces pombe. This mutant strain displayed resistance to both Ni2+ and Zn2+, but not to Cd2+, Co2+, and Cu2+. The growth rate of GA1 increased proportionally with increasing Mg2+ concentrations until 50 mM Mg2+. The GA1 mutation phenotype suggests a defect in Mg2+ uptake. Sequence analysis of the GA1 open reading frame (ORF) O13779, which is homologous to the prokaryotic and eukaryotic CorA Mg2+ transport systems, revealed a point mutation at codon 153 (ccc to acc) resulting in a Pro 153Thr substitution in the N-terminus
of the CorA domain. Our results provide novel genetic information about Ni2+ resistance in fission yeast. Specifically, that reducing Mg2+ influx through the CorA Mg2+ transport membrane protein confers Ni2+ resistance in S. pombe. We also report that Ni2+ ion detoxification of the fission yeast is related to histidine metabolism and pH. 相似文献
7.
Ladislav Kov
Vlasta Poliachov Istvn Horvth 《Biochimica et Biophysica Acta (BBA)/Molecular Cell Research》1982,721(4):349-356
The non-macrolid polyene antibiotic oleficin, which has been shown to function as an ionophore of Mg2+ in isolated rat liver mitochondria, preferentially inhibited growth of the yeast Saccharomyces cerevisiae on non-fermentable substrates. It uncoupled and inhibited respiration of intact cells and converted both growing and resting cells into respiration-deficient mutants. The mutants arose as a result of fragmentation of the mitochondrial genome. Another antibiotic known to be an ionophore of divalent cations, A23187, also selectively inhibited growth of the yeast on non-fermentable substrates, but did not produce the respiration-deficient mutants, neither antibiotic inhibited the energy-dependent uptake of divalent cations by yeast cells nor opened the plasma membrane for these cations. The results indicate that in Saccharomyces cerevisiae both oleficin and A23187 preferentially affected the mitochondrial membrane without acting as ionophores in the plasma membrane. 相似文献
8.
High concentrations of both ethanol and sugar in the fermentation broth inhibit the growth of yeast cells and the rate of product formation. Inhibitory effects of ethanol on the yeast strain Saccharomyces cerevisiae NRRL-Y-132 were studied in batch and continuous chemostat cultures. Growth was limited by either glucose or ethanol. Feed medium was supplemented with different ethanol concentrations. Ethanol was found to inhibit growth and the activity of yeast to produce ethanol in a noncompetitive manner. A linear kinetic pattern for growth and product formation was observed according to μ = μm (1 – P/Pm) and v = vm (1 – P/Pm′), where μm is the maximum specific growth rate at P = 0 (hr?1); Pm is the maximum specific product formation rate at P = 0 (hr?1); Pm is the maximum ethanol concentration above which cells do not grow (g/liter); Pm′ is the maximum ethanol concentration above which cells do not produce ethanol (g/liter). Substrate inhibition studies were carried out using short-time experimental techniques under aerobic and anaerobic condition. The degree of substrate inhibition was found to be higher than that has been reported for ethanol fermentation of pure sugar. The kinetic relationships thus obtained were used to compute growth, substrate utilization, and alcohol production patterns and have been discussed with reference to batch and continuous fermentation of enzymatically produced bagasse hydrolysate. 相似文献
9.
Optimum conditions for action of the killer toxin K1 on sensitive strainS. cerevisiae S6 were established. Maximum killing was reached in a very narrow pH range of 4.5–4.6. Maximum susceptibility to toxin was
displayed by highly energized fresh cells from the early exponential phase in the presence of an external energy source (at
least 200 mmol/L glucose). Further, maintenance of maximum membrane potential was necessary for killer action, as documented
by decreasing toxin activity in the presence of increasing concentrations of KCl. The killing was strongly stimulated in the
presence of millimolar concentrations of Ca2+ and Mg2+. 相似文献
10.
The magnesium content of Saccharomyces cerevisiae was found to vary by up to fivefold at differing␣ stages of batch growth and during growth in the presence of differing magnesium
concentrations. Excess Mg was primarily sequestered in vacuoles. Mn2+-uptake experiments revealed that Mg-enriched cells had a markedly reduced capacity for Mn2+ accumulation. For example, after 6 h incubation in the presence of 50 μM Mn2+, Mn levels were approximately twofold higher in cells previously grown in unsupplemented medium than in those from Mg-supplemented
medium. These differences were further accentuated at higher Mn2+ concentrations and were not attributable to altered cell-surface charge or altered cell-surface Mn2+ binding. Cellular Mg status also influenced Mn toxicity towards S. cerevisiae. During exposure to 5 mM Mn2+, 50% reductions in the viability of cells with initial Mg contents of approximately 1400 and 2700 nmol (109 cells)−1 occurred after approximately 1.6 h and 3.6 h respectively. In cells containing 3300 nmol Mg (109 cells)−1, more than 75% viability was still maintained after 7 h incubation with 5 mM Mn2+. It is concluded that Mn2+ uptake and toxicity in S. cerevisiae are strongly influenced by intracellular Mg, possibly through Mg-dependent regulation of divalent-cation transport activity.
Received: 15 May 1996 / Received revision: 13 September 1996 / Accepted: 22 September 1996 相似文献
11.
Shokrollahzadeh S Bonakdarpour B Vahabzadeh F Sanati M 《Journal of industrial microbiology & biotechnology》2007,34(1):17-25
The effect of phosphate (P
i
) concentration on the growth behavior of Saccharomyces cerevisiae strain CEN.PK113-5D in phosphate-limited batch and chemostat cultures was studied. The range of dilution rates used in the present study was 0.08–0.45 h−1. The batch growth of yeast cells followed Monod relationship, but growth of the cells in phosphate-limited chemostat showed change in growth kinetics with increasing dilution rates. The difference in growth kinetics of the yeast cells in phosphate-limited chemostat for dilution rates below and above approximately 0.2 h−1 has been discussed in terms of the batch growth kinetic data and the change in the metabolic activity of the yeast cells. Immunological detection of a C-terminally myc epitope-tagged Pho84 fusion protein indicated derepressive expression of the Pho84 high-affinity P
i
transporter in the entire range of dilution rates employed in this study. Phosphate transport activity mediated by Pho84 transporter was highest at very low dilution rates, i.e. 0.08–0.1 h−1, corresponding to conditions in which the amount of synthesized Pho84 was at its maximum. 相似文献
12.
Ladislav Kov
《Biochimica et Biophysica Acta (BBA)/General Subjects》1985,840(3):317-323
The claim that Ca may be a dispensable element for yeast Saccharomyces cerevisiae has been reexamined. The cells of S. cerevisiae could grow in media which contained no added Ca and were deprived of contaminating Ca2+ by filtration through a Chelex 100 column. Also, the cells were able to grow in the presence of fairly high concentrations of EGTA. The apparent intracellular concentrations of Ca, assessed from the content of radioactive 45Ca in cells preloaded with 45CaCl2, could vary within the range of approx. 2 nM to 2.8 mM, without adversively affecting growth or morphology of the cells. An extremely low affinity for Ca2+ of the system taking up Ca into the cells was corroborated. However, even the Chelex 100-treated media were found in contain 1–5 μM Ca when maintained in glass culture vessels. Also, the ability of the cells to take up Ca from a medium containing surplus of EGTA or EDTA was demonstrated. su14CEDTA, alone or in the presence of Ca, could also be transported into the cells. It has been inferred that Ca must be as essential for yeast as it is for other eucaryotic organisms. The omnipresence of contaminating Ca and peculiarities of the Ca transporting system, combined with an intricate intracellular compartmentation of Ca, would account for the impossibility to prove the importance of Ca for yeast by direct growth studies. 相似文献
13.
Tatyana V. Votyakova Elena N. Bazhenova Renata A. Zvjagilskaya 《Journal of bioenergetics and biomembranes》1993,25(5):569-574
Spermine, spermidine, and magnesium ions modulate the kinetic parameters of the Ca2+ transport system ofEndomyces magnusii mitochondria. Mg2+ at concentrations up to 5 mM partially inhibits Ca2+ transport with a half-maximal inhibiting concentration of 0.5 mM. In the presence of 2 mM MgCl2, theS
0.5 value of the Ca2+ transport system increases from 220 to 490 µM, which indicates decreased affinity for the system. Spermine and spermidine exert an activating effect, having half-maximal concentrations of 12 and 50 µM, respectively. In the case of spermine, theS
0.5 value falls to 50–65 µM, which implies an increase in the transport system affinity for Ca2+. Both Mg2+ and spermine cause a decrease of the Hill coefficient, giving evidence for a smaller degree of cooperativity. Spermine and spermidine enable yeast mitochondria to remove Ca2+ from the media completely. In contrast, Mg2+ lowers the mitochondrial buffer capacity. When both Mg2+ and spermine are present in the medium, their effects on theS
0.5 value and the free extramitochondrial Ca2+ concentration are additive. The ability of spermine and Mg2+ to regulate yeast mitochondrial Ca2+ transport is discussed. 相似文献
14.
We are developing budding yeast, Saccharomyces cerevisiae, as a genetic system for the study of tolerance to the trivalent aluminum cation (Al3+). We have isolated eight mutants that are more sensitive to Al3+ than the wild type. Each mutant represented a different complementation group. A number of the mutants were pleiotropic,
and showed defects in other stress responses, changes in tolerance to other metal cations, or abnormal morphology. Two mutants
also showed increased dependence on supplemental Mg2+ and Ca2+. One mutant with a relatively specific sensitivity to Al3+ was chosen for molecular complementation. Normal Al3+ tolerance was restored by expression of the MAP kinase gene SLT2. Strains carrying deletions of the SLT2 gene, or of the gene for the corresponding MAP kinase–kinase SLK1, showed sensitivity to Al3+. These results indicate that the SLT2 MAP kinase signal transduction pathway is required for yeast to sense and respond to Al3+ stress.
Received: 17 April 1996 / Accepted: 21 October 1996 相似文献
15.
Masa-aki Okuyama Yoshihiro Kobayashi Masahiro Inouhe Hiroshi Tohoyama Masanori Joho 《Biometals》1999,12(4):307-314
Copper-induced metallothionein (MT) synthesis in Saccharomyces cerevisiae was investigated in order to associate this exclusively with Cu2+
in vivo, when cultured in nutrient medium containing other heavy metal ions. Expression of the CUP1 promoter/lacZ fusion gene was inhibited by all heavy metal ions tested, especially Cd2+ and Mn2+. By adding Cd2+ and Mn2+ at 10 M concentration, the -galactosidase activity decreased by about 80% and 50% of the maximum induction observed with 1 mM CuSO4, respectively. Furthermore, cell growth was markedly inhibited by combinations of 1 mM-Cu2+ and 1 M-Cd2+. Therefore, the yeast S. cerevisiae could not rely on MT synthesis as one of the copper-resistance mechanisms, when grown in a Cd2+ environment. In contrast, the presence of Mn2+ in the nutrient medium showed alleviation rather than growth inhibition by high concentrations of Cu2+. The recovery from growth inhibition by Mn2+ was due to decreased Cu2+ accumulation. Inhibitory concentrations of Co2+, Ni2+ and Zn2+ on expression of the CUP1p/lacZ fusion gene were at least one order of magnitude higher than that of Cd2+ and Mn2+. These results are discussed in relation to Cu2+ transport and Cu-induced MT synthesis in the copper-resistance mechanism of the yeast S. cerevisiae. 相似文献
16.
Yeast suffers from a variety of environmental stresses, such as osmotic pressure and ethanol produced during fermentation.
Since calcium ions are protective for high concentrations of ethanol, we investigated whether Ca2+ flux occurs in response to ethanol stress. We find that exposure of yeast to ethanol induces a rise in the cytoplasmic concentration
of Ca2+. The response is enhanced in cells shifted to high-osmotic media containing proline, galactose, sorbitol, or mannitol. Suspension
of cells in proline and galactose-containing media increases the Ca2+ levels in the cytoplasm independent of ethanol exposure. The enhanced ability for ethanol to induce Ca2+ flux after the hypertonic shift is transient, decreasing rapidly over a period of seconds to minutes. There is partial recovery
of the response after zymolyase treatment, suggesting that cell wall integrity affects the ethanol-induced Ca2+ flux. Acetate inhibits the Ca2+ accumulation elicited by the ethanol/osmotic stress. The Ca2+ flux is primarily via the Cch1 Ca2+ influx channel because strains carrying deletions of the cch1 and mid1 genes show greater than 90% reduction in Ca2+ flux. Furthermore, a functional Cch1 channel reduced growth inhibition by ethanol. 相似文献
17.
Intracellular distributions of K+, Mg2+ and orthophosphate under various conditions of cultivation or incubation of the yeast Saccharomyces carlsbergensis were studied by differential extraction of ion pools. The decisive role of vacuolar compartmentation of ions in regulation of K+, Mg2+ and orthophosphate levels in the yeast cytoplasm was shown. The content of intracellular K+ and Mg2+ in yeast increased or decreased primarily depending on the increase or decrease in the vacuolar ion pool. The levels of K+ and Mg2+ in the cytoplasm were practically unchanged. Vacuoles were involved in regulation of Mn2+ concentration in the cytoplasm of the yeast S. carlsbergensis accumulating this ion in the presence of glucose. Alongside the vacuolar compartmentation, the chemical compartmentation, i. e. formation of bound Mg2+, Mn2+ and K+ was, evidently, also involved in the control of ion levels in the cytoplasm. The orthophosphate level in the yeast cytoplasm was regulated by its accumulation in vacuoles and biosynthesis of inorganic polyphosphates in these organelles. The biosynthesis of low-molecular weight polyphosphates occurred parallel to the accumulation of Mg2+ or Mn2+ in vacuoles, thus confirming the availability of the other mechanism for the transport of these ions through the tonoplast differing from the transport mechanism through the plasmalemma. 相似文献
18.
Birgitte K. Ahring Felipe Alatriste-Mondragon Peter Westermann Robert A. Mah 《Applied microbiology and biotechnology》1991,35(5):686-689
Summary The effects of different concentrations of Mg2+, Ca2+, or Na+ on the morphology and growth of Methanosarcina thermophila TM-1 growing on acetate at concentrations comparable with those found in anaerobic digestors was studied. At 30 mm Mg2+ or less, M. thermophila grew as large aggregates that settled rapidly. At 100 mm Mg2+ or more, the bacteria grew as single cells or a mixture of single cells and small aggregates is suspended culture. Mg2+ was necessary for growth and could not be substituted by addition of either Ca2+ or Na+. The optimal Mg2+ concentration was 30 mm and no growth was observed at 400 mm Mg2+. Cultures could be adapted to 300 mm Mg2+ without a change in growth rate. Added Ca2+ was not required for growth and had no effect on cell morphology. Inhibition by Na+ was directly related to the Mg2+ concentration. When the Mg2+ was 0.05 mm or less, 0.35 m Na+ completely inhibited growth. However, more Na+ was required for inhibition at higher Mg2+ concentrations. The same inhibitory effect of Na+ was observed when the temperature was 52°C or 45°C. The potential for disaggregation of Methanosarcina aggregates in anaerobic digestor environments was discussed.
Offprint requests to: B. K. Ahring 相似文献
19.
V. M. Vagabov L. V. Trilisenko O. Yu. Kochetkova A. P. Ilchenko I. S. Kulaev 《Microbiology》2011,80(1):15-20
The effects of different concentrations of the protonophore uncoupler m-carbonyl cyanide 3-hchlorophenylhydrazone (CCCP) on the synthesis of inorganic polyphosphates (polyP) during the first 0.5
h of hypercompensation in the yeast Saccharomyces cerevisiae VKM Y-1173 growing on media with 2% glucose under low (hypoxia) or high aeration or with 1% (vol/vol) ethanol under high
aeration were studied. It was shown that the yeast growth on ethanol was completely inhibited by 5 μM CCCP, while growth on
glucose was inhibited by 25 μM CCCP, independently of aeration of the medium. The maximum rate of H2 absorption was shown
at 2, 5, and 25 μM CCCP for the cells grown on ethanol, on glucose under high aeration, and on glucose under hypoxia, respectively.
Against the decrease of total ATP level and total polyP, CCCP had a nonuniform effect on the synthesis of individual polyP
fractions. CCCP maximally inhibited synthesis of the most actively formed fractions: polyPI during growth on glucose under
hypoxia, polyPIII during growth on glucose under aeration, and polyPIII and polyPV during growth on ethanol. CCCP had no substantial
effect on the synthesis of polyPII and polyPIV fractions, the formation of which seems to be less related to the electrochemical
potential gradient of H+ ions. 相似文献
20.
Pszon-Bartosz K Hansen JS Stibius KB Groth JS Emnéus J Geschke O Hélix-Nielsen C 《Biochemical and biophysical research communications》2011,414(1):96-100
The gene for a putative cation calcium exchanger (CCX) from Arabidopsis thaliana, AtCCX5, was cloned and its function was analyzed in yeast. Green fluorescent protein-tagged AtCCX5 expressed in yeast was localized in the plasma membrane and nuclear periphery. The yeast transformants expressing AtCCX5 were created and their growth in the presence of various cations (K+, Na+, Ca2+, Mg2+, Fe2+, Cu2+, Co2+, Cd2+, Mn2+, Ba2+, Ni2+, Zn2+, and Li+) were analyzed. AtCCX5 expression was found to affect the response to K+ and Na+ in yeast. The AtCCX5 transformant also showed a little better growth to Zn2+. The yeast mutant 9.3 expressing AtCCX5 restored growth of the mutant on medium with low K+ (0.5 mM), and also suppressed its Na+ sensitivity. Ion uptake experiments showed that AtCCX5 mediated relatively high-affinity K+ uptake and was also involved in Na+ transport in yeast. Taken together, these findings suggest that the AtCCX5 is a novel transport protein involves in mediating high-affinity K+ uptake and Na+ transport in yeast. 相似文献