Yeast cells

The effect of different nitrogen sources on cell growth and polyhydroxyalkanoate (PHA) accumulation by halophilic bacterium strain Yangia sp. ND199 was investigated. The combination of 0.5 g/L potassium nitrate (KNO3) and 0.5 g/L yeast extract was shown to be good nitrogen source for cell growth and PHBV production by Yangia sp. ND199.

6p tamynhan5 10-12-2020 10 3   Download

Fermentation is a complicated process which depends on a variety of conditions. In order to gain high fermentation efficiency with a low level of toxins and impurities to obtain good products, it is essential to determine suitable conditions for the process. Within the scope of this study, the effects of some key conditions was estimated (i.e. pH, temperature, SO2 level in fermentation broth, the inoculation rates of yeast cells, sugar level) for the fermentation of corn with Saccharomyces cerevisiae MS42.

8p tamynhan9 02-12-2020 43 3   Download

Deproteinated cheese whey was used for biomass production of probiotic strain Lactobacillus helveticus MTCC 5463 in a biofermenter. Optimization of growth parameters such as temperature, pH and time of incubation as well as nutrient supplementation of cheese whey was carried out using response surface methodology (RSM). Cheese whey supplemented with 0.95% yeast extract and 0.95% proteose peptone, inoculated with 6% (v/v) active culture of L. helveticus MTCC 5463 and fermented for 24 h at optimized temperature of 40ºC and pH 6.25 yielded 3.25 g/L dry cell biomass and 14.

14p chauchaungayxua6 26-06-2020 25 3   Download

Trehalose metabolism is an essential component of the stress response in yeast cells. In this work we show that the products of the principal genes involved in trehalose metabolism in Schizosaccharomyces pombe, tps1+ (coding for trehalose6-P synthase, Tps1p), ntp1+ (encoding neutral trehalase, Ntp1p) and tpp1+ (that codes for trehalose-6-P phosphatase, Tpp1p), interact in vitro with each other and with themselves to form protein complexes. Disruption of the gene tps1+ blocks the activation of the neutral trehalase induced by heat shock but not by osmotic stress.

9p system191 01-06-2013 28 4   Download

An oxidosqualene cyclase cDNA, LcIMS1, was isolated from cultured cells of Luffa cylindrica Roem. by heterologous hybridization with cDNA of Glycyrrhiza glabra b-amyrin synthase. Expression of LcIMS1 in yeast lacking endogenous oxidosqualene cyclase activity resulted in the accumulation of isomultiflorenol, a triterpene. This is consistent with LcIMS1 encoding isomultiflorenol synthase, an oxidosqualene cyclase involved in bryonolic acid biosynthesis in cultured Luffa cells.

7p system191 01-06-2013 50 5   Download

Tyrosyl-DNA phosphodiesterase (TDP) cleaves the phosphodiester bond linking the active site tyrosine residue of topoisomerase I with the 3¢ terminus of DNA in topoisomerase I–DNA complexes which accumulate during treatment of cancer with camptothecin. In yeast, TDP mutation confers a 1000-fold hypersensitivity to camptothecin in the presence of an additional mutation of RAD9 gene [Pouliot, J.J., Yao, K.C., Robertson, C.A. & Nash, H.A. (1999) Science 286, 552–555].

8p research12 01-06-2013 32 2   Download

We previously reported that GTS1 is involved in regulating ultradian oscillations of the glycolytic pathway induced by cyanide in cell suspensions as well as oscillations of energy metabolism in aerobic continuous cultures. Here, we screened a yeast cDNA library for proteins that bind to Gts1p using the yeast two-hybrid system and cloned multiple TDH cDNAs encoding the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH).

10p research12 01-06-2013 40 3   Download

The p25rum1 is an inhibitor of Cdc2 kinase expressed in fission yeast and plays an important role in cell-cycle control. As its amino-acid sequence suggests that p25rum1 has putative phosphorylation sites for mitogen-activated protein kinase (MAPK), we investigated the ability of MAPK to phosphorylate p25rum1. Direct in vitro kinase assay using GST-fusion proteins of wild-type as well as various mutants of p25rum1 demonstrated that MAPK phosphorylates the N-terminal portion of p25rum1 and residues Thr13 and Ser19 are major phosphorylation sites for MAPK....

11p research12 01-06-2013 46 4   Download

The centromere–kinetochore complex is a highly specialized chromatin domain that both mediates and monitors chromosome–spindle interactions responsible for accurate partitioning of sister chromatids to daughter cells. Centromeres are distinguished from adjacent chromatin by specific patterns of histone modification and the presence of a centromere-specific histone H3 variant (e.g. CENP-A). Centromere-proximal regions usually correspond to sites of avid and persistent sister chromatid cohesion mediated by the conserved cohesin complex.

15p research12 01-06-2013 49 4   Download

During the last decade several novel yeast genes encoding proteins related to the PPP family of Ser/Thr protein phosphatases have been discovered and their functional characterization initiated. Most of these novel phosphatases display intriguing structural features and/or are involved in a number of important functions, such as cell cycle regulation, protein synthesis and maintenance of cellular integrity. While in some cases these genes appear to be restricted to fungi, in others similar proteins can be found in higher eukaryotes. ...

6p research12 01-06-2013 27 3   Download

The eukaryotic glyoxylate cycle has been previously hypothesized to occur in the peroxisomal compartment, which in the yeast Saccharomyces cerevisiae additionally represents the sole site for fatty acid b-oxidation. The subcellular location of the key glyoxylate-cycle enzyme malate synthase 1 (Mls1p), an SKL-terminated protein, was examined in yeast cells grown on di€erent carbon sources.

8p research12 01-06-2013 42 4   Download

Eukaryotic ribonuclease (RNase) H2 consists of one catalytic and two accessory subunits. Several single mutations in any one of these subunits of human RNase H2 cause Aicardi–Goutie`res syndrome. To examine whether these mutations affect the complex stability and activity of RNase H2, three mutant proteins of His-tagged Saccharomyces cerevisiaeRNase H2 (Sc-RNase H2*) were constructed. Sc-G42S*, Sc-L52R*, and Sc-K46W* contain single mutations in Sc-Rnh2Ap*, Sc-Rnh2Bp*, and Sc-Rnh2Cp*, respectively....

14p research12 29-04-2013 38 1   Download

The 26S proteasome, a protein complex consisting of a 20S proteasome and a pair of 19S regulatory particles (RP), is involved in ATP-dependent proteolysis in eukaryotes. In yeast, theRP contains six different ATPase subunits and, at least, 11 non-ATPase subunits. In this study, we identi®ed the rice homologs of yeast RP subunit genes from the rice expressed sequence tag (EST) library.

10p research12 29-04-2013 38 3   Download

We used parameter scanning to emulate changes to the limitingrate for steps inafittedmodel of glucose-derepressed yeast glycolysis. Three flux-control regimes were observed, two of which were under the dominant control of hexose transport, in accordance with various experimental studies andothermodel predictions.

11p research12 23-04-2013 41 2   Download

Hemolin, a plasma protein from lepidopteran insects, is composed of four immunoglobulin domains. Its synthesis is induced by microbial challenge. We investigated the biological functions of hemolin inManduca sexta.It was found to bind to the surface of bacteria and yeast, and caused these micro-organisms to aggregate. Hemolin was demonstrated to bind to lipopolysaccharide (LPS) from Gram-negativebacteriaand to lipoteichoic acid fromGram-positive bacteria.

8p research12 23-04-2013 36 2   Download

Important hydrogenbonding interactions between substrate OH-groups inyeasta-glucosidases andoligo-1,6-glucosidase from glycoside hydrolase family 13 have been identi®ed by measuring the rates of hydrolysis of methyla-isomaltoside and its seven monodeoxygenated analogs. The transition-state stabilization energy, DDGà, contributed by the indi-vidual OH-groups was calculated from the activities for the parent and the deoxy analogs, respectively, according toDDGà ˆ±RTln[(Vmax/Km)analog /(Vmax/Km) parent]....

7p research12 23-04-2013 29 2   Download

Genomicfattyacid elongation 1 (FAE1) clones from high erucic acid (HEA)Brassica napus, Brassica rapaandBras-sicaoleracea, and lowerucicacid (LEA)B. napuscv.Westar, were amplifiedbyPCRand expressed inyeast cells under the control of the strong galactose-inducible promoter. As expected, yeast cells expressing theFAE1genes from HEA Brassicaspp. synthesized very long chain monounsaturated fatty acids that are not normally found in yeast, while fatty acid profiles of yeast cells expressing theFAE1gene from LEA B. napuswere identical to control yeast samples....

7p tumor12 22-04-2013 41 2   Download

Human cytochrome P450 17a-hydroxylase (CYP17) cata-lyses not only the 17a-hydroxlation of pregnenolone and progesterone and the C17,20-side chain cleavage (lyase) of 17a-hydroxypregnenolone, necessary for the biosynthesis of C21-glucocorticoids and C19-androgens, but also catalyses the 16a-hydroxylation of progesterone. In efforts to under-stand the complex enzymology of CYP17, structure/func-tion relationships have been reported previously after expressingrecombinant DNAs, encodingCYP17 from various species, in nonsteroidogenic mammalian or yeast cells. ...

9p tumor12 22-04-2013 42 2   Download

Novel properties of the primer independent synthesis of poly(A), catalyzed by the yeast poly(A) polymerase are presented.The commercial enzyme fromyeast, incontrast to theenzymefromEscherichia coli, is unable to adenylate the 3¢-OH end of nucleosides, nucleotides or dinucleoside poly-phosphates (NpnN).

7p tumor12 22-04-2013 33 3   Download

The ability of aminoacyl-tRNA synthetases to distinguish betweensimilaraminoacidsiscrucial foraccuratetrans-lation of the genetic code. Saccharomyces cerevisiae seryl-tRNA synthetase (SerRS) employs tRNA-dependent recognition of its cognate amino acid serine [Lenhard, B., Filipic, S., Landeka, I., Skrtic, I., So¨ll, D. & Weygand-Durasevic, I. (1997)J. Biol. Chem.272, 1136–1141]. Herewe show that dimeric SerRS enzyme complexed with one molecule of tRNA Ser is more specific and more efficient in catalyzing seryl-adenylate formation than the apoenzyme alone. ...

9p tumor12 22-04-2013 37 1   Download