The Experts below are selected from a list of 213 Experts worldwide ranked by ideXlab platform

Sisinthy Shivaji - One of the best experts on this subject based on the ideXlab platform.

  • Role of Glycerol-3-Phosphate Dehydrogenase 2 in mouse sperm capacitation.
    Molecular reproduction and development, 2010
    Co-Authors: Venkatesh Kota, Priyanka Rai, Joachim M. Weitzel, Ralf Middendorff, Satish S. Bhande, Sisinthy Shivaji
    Abstract:

    A tyrosine phosphoproteome study of hamster spermatozoa indicated that Glycerol-3-Phosphate Dehydrogenase 2 (GPD2), is one of the proteins that enables tyrosine phosphorylation during sperm capacitation. Further, enzymatic activity of GPD2 correlated positively with sperm capacitation [Kota et al., 2009; Proteomics 9:1809–1826]. Therefore, understanding the function of GPD2 would help to unravel the molecular mechanism of sperm capacitation. In this study, involving the use of spermatozoa from Gpd2+/+ and Gpd2−/− mice, it has been demonstrated that in the absence of Gpd2, hyperactivation and acrosome reaction were significantly altered, and a few changes in protein tyrosine phosphorylation were also observed during capacitation. Evidence is provided to demonstrate that GPD2 activity is required for ROS generation in mouse spermatozoa during capacitation, failing which, capacitation is impaired. These results imply that GPD2 is involved in sperm capacitation. Mol. Reprod. Dev. 77: 773–783, 2010. © 2010 Wiley-Liss, Inc.

  • Role of Glycerol-3-Phosphate Dehydrogenase 2 in mouse sperm capacitation.
    Molecular reproduction and development, 2010
    Co-Authors: Venkatesh Kota, Priyanka Rai, Joachim M. Weitzel, Ralf Middendorff, Satish S. Bhande, Sisinthy Shivaji
    Abstract:

    A tyrosine phosphoproteome study of hamster spermatozoa indicated that Glycerol-3-Phosphate Dehydrogenase 2 (GPD2), is one of the proteins that enables tyrosine phosphorylation during sperm capacitation. Further, enzymatic activity of GPD2 correlated positively with sperm capacitation [Kota et al., 2009; Proteomics 9:1809-1826]. Therefore, understanding the function of GPD2 would help to unravel the molecular mechanism of sperm capacitation. In this study, involving the use of spermatozoa from Gpd2(+/+) and Gpd2(-/-) mice, it has been demonstrated that in the absence of Gpd2, hyperactivation and acrosome reaction were significantly altered, and a few changes in protein tyrosine phosphorylation were also observed during capacitation. Evidence is provided to demonstrate that GPD2 activity is required for ROS generation in mouse spermatozoa during capacitation, failing which, capacitation is impaired. These results imply that GPD2 is involved in sperm capacitation.

Venkatesh Kota - One of the best experts on this subject based on the ideXlab platform.

  • Role of Glycerol-3-Phosphate Dehydrogenase 2 in mouse sperm capacitation.
    Molecular reproduction and development, 2010
    Co-Authors: Venkatesh Kota, Priyanka Rai, Joachim M. Weitzel, Ralf Middendorff, Satish S. Bhande, Sisinthy Shivaji
    Abstract:

    A tyrosine phosphoproteome study of hamster spermatozoa indicated that Glycerol-3-Phosphate Dehydrogenase 2 (GPD2), is one of the proteins that enables tyrosine phosphorylation during sperm capacitation. Further, enzymatic activity of GPD2 correlated positively with sperm capacitation [Kota et al., 2009; Proteomics 9:1809–1826]. Therefore, understanding the function of GPD2 would help to unravel the molecular mechanism of sperm capacitation. In this study, involving the use of spermatozoa from Gpd2+/+ and Gpd2−/− mice, it has been demonstrated that in the absence of Gpd2, hyperactivation and acrosome reaction were significantly altered, and a few changes in protein tyrosine phosphorylation were also observed during capacitation. Evidence is provided to demonstrate that GPD2 activity is required for ROS generation in mouse spermatozoa during capacitation, failing which, capacitation is impaired. These results imply that GPD2 is involved in sperm capacitation. Mol. Reprod. Dev. 77: 773–783, 2010. © 2010 Wiley-Liss, Inc.

  • Role of Glycerol-3-Phosphate Dehydrogenase 2 in mouse sperm capacitation.
    Molecular reproduction and development, 2010
    Co-Authors: Venkatesh Kota, Priyanka Rai, Joachim M. Weitzel, Ralf Middendorff, Satish S. Bhande, Sisinthy Shivaji
    Abstract:

    A tyrosine phosphoproteome study of hamster spermatozoa indicated that Glycerol-3-Phosphate Dehydrogenase 2 (GPD2), is one of the proteins that enables tyrosine phosphorylation during sperm capacitation. Further, enzymatic activity of GPD2 correlated positively with sperm capacitation [Kota et al., 2009; Proteomics 9:1809-1826]. Therefore, understanding the function of GPD2 would help to unravel the molecular mechanism of sperm capacitation. In this study, involving the use of spermatozoa from Gpd2(+/+) and Gpd2(-/-) mice, it has been demonstrated that in the absence of Gpd2, hyperactivation and acrosome reaction were significantly altered, and a few changes in protein tyrosine phosphorylation were also observed during capacitation. Evidence is provided to demonstrate that GPD2 activity is required for ROS generation in mouse spermatozoa during capacitation, failing which, capacitation is impaired. These results imply that GPD2 is involved in sperm capacitation.

Bernard A Prior - One of the best experts on this subject based on the ideXlab platform.

  • Characterization of the osmotic-stress response in Saccharomyces cerevisiae: osmotic stress and glucose repression regulate Glycerol-3-Phosphate Dehydrogenase independently.
    Current Genetics, 1994
    Co-Authors: Jacobus Albertyn, Stefan Hohmann, Bernard A Prior
    Abstract:

    Micro-organisms have developed systems to adapt to sudden changes in the environment. Here we describe the response of the yeast Saccharomyces cerevisiae to osmotic stress. A drop in the water activity (aw) of the medium following the addition of NaCl led to an immediate shrinkage of the cells. During the 2 h following the osmotic shock the cells partially restored their cell volume. This process depended on active protein synthesis. During the recovery period the cells accumulated glycerol intracellularly as a compatible solute and very little glycerol was leaking out of the cell. We have investigated in more detail the enzymes of glycerol metabolism and found that only the cytoplasmic Glycerol-3-Phosphate Dehydrogenase was strongly induced. The level of induction was dependent on the yeast strain used and the degree of osmotic stress. The synthesis of cytoplasmic Glycerol-3-Phosphate Dehydrogenase is also regulated by glucose repression. Using mutants defective in glucose repression (hxk2 delta), or derepression (snf1 delta), and with invertase as a marker enzyme, we show that glucose repression and the osmotic-stress response system regulate Glycerol-3-Phosphate Dehydrogenase synthesis independently. We infer that specific control mechanisms sense the osmotic situation of the cell and induce responses such as the production and retention of glycerol.

  • Purification and characterization of glycerol‐3‐phosphate Dehydrogenase of Saccharomyces cerevisiae
    FEBS letters, 1992
    Co-Authors: Jacobus Albertyn, André Van Tonder, Bernard A Prior
    Abstract:

    The NAD-dependent Glycerol-3-Phosphate Dehydrogenase (Glycerol-3-Phosphate:NAD+ oxidoreductase; EC 1.1.1.8; G3P DHG) was purified 178-fold to homogeneity from Saccharomyces cerevisiae strain H44-3D by affinity- and ion-exchange chromatography. SDS-PAGE indicated that the enzyme had a molecular mass of approximately 42,000 (+/- 1,000) whereas a molecular mass of 68,000 was observed using gel filtration, implying that the enzyme may exist as a dimer. The pH optimum for the reduction of dihydroxyacetone phosphate (DHAP) was 7.6 and the enzyme had a pI of 7.4. NADPH will not substitute for NADH as coenzyme in the reduction of DHAP. The oxidation of Glycerol-3-Phosphate (G3P) occurs at 3% of the rate of DHAP reduction at pH 7.0. Apparent Km values obtained were 0.023 and 0.54 mM for NADH and DHAP, respectively. NAD, fructose-1,6-bisphosphate (FBP), ATP and ADP inhibited G3P DHG activity. Ki values obtained for NAD with NADH as variable substrate and FBP with DHAP as variable substrate were 0.93 and 4.8 mM, respectively.

Francis Mcodimba - One of the best experts on this subject based on the ideXlab platform.

  • Purification of sn-Glycerol-3-Phosphate Dehydrogenase from Trypanosoma brucei brucei.
    Biochemistry and Cell Biology, 1992
    Co-Authors: Jack A. Kornblatt, Joseph Nthale, Francis Mcodimba
    Abstract:

    A protein has been purified from the membranes of bloodstream forms of Trypanosoma brucei brucei. The purified material contained a single polypeptide chain of molecular mass 67 kilodaltons as judged by sodium dodecyl sulfate –polyacrylamide gel electrophoresis; under "native" conditions it migrated through a Sephacryl S-300 column with a similar molecular mass. The purified protein catalysed electron transfer from sn-glycerol 3-phosphate to oxygen with the subsequent formation of water. Electron transfer by the purified enzyme to O2 was dependent on the presence of low concentrations of the mediator phenazine methosulfate. This protein is clearly the major membrane-bound sn-Glycerol-3-Phosphate Dehydrogenase, but it also has some characteristics suggestive of the trypanosome alternative oxidase activities.Key words: trypanosomes, glycerophosphate Dehydrogenase, trypanosome alternative oxidase.

Hans J. Seitz - One of the best experts on this subject based on the ideXlab platform.

  • Cloning of a cDNA for the FAD-linked Glycerol-3-Phosphate Dehydrogenase from rat liver and its regulation by thyroid hormones
    Proceedings of the National Academy of Sciences of the United States of America, 1994
    Co-Authors: Stefan Müller, Hans J. Seitz
    Abstract:

    A full-length 2.4-kb cDNA for the FAD-linked Glycerol-3-Phosphate Dehydrogenase (EC 1.1.99.5) was cloned from rat liver using PCR techniques. The cloned gene encodes a protein of 727 amino acids. The calculated molecular mass of 80,898 Da is higher than the apparent molecular mass observed by SDS/PAGE (74,000 Da) of the purified enzyme. This result indicates that the enzyme is synthesized as a precursor with a putative mitochondrial signal sequence. mRNA for this gene was detected in liver, heart, muscle, brain, testes, and pancreas. With the exception of testes, basal expression levels were very low in all tissues examined. However, application of thyroid hormones led to a 10- to 15-fold increase in liver Glycerol-3-Phosphate Dehydrogenase mRNA, whereas hypothyroidism further decreased the mRNA level.