The role of the mitochondrial NAD+: isocitrate dehydrogenase in lipid accumulation by the oleaginous yeast Rhodosporidium toruloides CBS 14

1985 ◽  
Vol 31 (9) ◽  
pp. 845-850 ◽  
Author(s):  
Christopher Thomas Evans ◽  
Colin Ratledge
Keyword(s):  
Isocitrate Dehydrogenase ◽  
Organic Nitrogen ◽  
Oleaginous Yeast ◽  
Potent Inhibitor ◽  
Rhodosporidium Toruloides ◽  
Strong Inhibition ◽  
Oleaginous Yeasts ◽  
Ph Optimum ◽  
Molecular Radius

The mitochondrial NAD+: isocitrate dehydrogenase from Rhodosporidium toruloides CBS 14 had a molecular radius of 191 800 daltons, a pH optimum of 7.8, and an apparent Kms for isocitrate and NAD+ of 109 and 365 μM, respectively. The enzyme was absolutely dependent on AMP for activity and showed sigmoidal activation curves with respect to isocitrate concentration. ATP was shown to be a potent inhibitor even in the presence of saturating AMP and isocitrate concentrations. NADH was the most potent inhibitor, followed by L-glutamate and α-ketoglutarate, and less strongly by citrate and oxaloacetate. The inhibition by L-glutamate and α-ketoglutarate was noncompetitive, with respect to isocitrate, and indicated that the enzyme could be very susceptible to regulation by the products of organic nitrogen metabolism in this yeast. Inhibition by citrate and more so the strong inhibition by NADH illustrated the interplay between the inactivation of NAD+: isocitrate dehydrogenase and the steps leading to the biosynthesis of acetyl-CoA. The key role of this enzyme in lipid biosynthesis in oleaginous yeasts is discussed.

Characterization of the mitochondrial NAD+-dependent isocitrate dehydrogenase of the oleaginous yeast Rhodosporidium toruloides

2012 ◽  
Vol 94 (4) ◽  
pp. 1095-1105 ◽  
Author(s):  
Fan Yang ◽  
Sufang Zhang ◽  
Yongjin J. Zhou ◽  
Zhiwei Zhu ◽  
Xinping Lin ◽  
...  
Keyword(s):  
Isocitrate Dehydrogenase ◽  
Oleaginous Yeast ◽  
Rhodosporidium Toruloides

Analysis of the light regulatory mechanism in carotenoid production in Rhodosporidium toruloides NBRC 10032

2021 ◽  
Author(s):  
Khanh Dung Pham ◽  
Yuuki Hakozaki ◽  
Takeru Takamizawa ◽  
Atsushi Yamazaki ◽  
Harutake Yamazaki ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Oleaginous Yeast ◽  
Gene Activation ◽  
Light Response ◽  
Carotenoid Biosynthesis ◽  
Rhodosporidium Toruloides ◽  
End Joining ◽  
Carotenoid Production ◽  
Non Homologous End Joining

Abstract Light stimulates carotenoid production in an oleaginous yeast Rhodosporidium toruloides NBRC 10032 by promoting carotenoid biosynthesis genes. These genes undergo two-step of transcriptional activation. The potential light regulator, Cryptochrome DASH (CRY1), has been suggested to contribute to this mechanism. In this study, based on KU70 (a component of non-homologous end joining (NHEJ)) disrupting background, CRY1 disruptant was constructed to clarify CRY1 function. From analysis of CRY1 disruptant, it was suggested that CRY1 has the activation role of the carotenogenic gene expression. To obtain further insights into the light response, mutants varying carotenoid production were generated. Through analysis of mutants, the existence of the control two-step gene activation was proposed. In addition, our data analysis showed the strong possibility that R. toruloides NBRC 10032 is a homo-diploid strain.

Tridegin, a Novel Peptidic Inhibitor of Factor XIIIa from the Leech, Haementeria ghilianii, Enhances Fibrinolysis In Vitro

1997 ◽  
Vol 77 (05) ◽  
pp. 0959-0963 ◽  
Author(s):  
Lisa Seale ◽  
Sarah Finney ◽  
Roy T Sawyer ◽  
Robert B Wallis
Keyword(s):  
Potent Inhibitor ◽  
Platelet Rich Plasma ◽  
Factor Xiiia ◽  
Cross Linking ◽  
Fibrinolytic Enzymes ◽  
Small Polypeptide ◽  
Tissue Plasminogen ◽  
Protein Cross Linking

SummaryTridegin is a potent inhibitor of factor Xllla from the leech, Haementeria ghilianii, which inhibits protein cross-linking. It modifies plasmin-mediated fibrin degradation as shown by the absence of D-dimer and approximately halves the time for fibrinolysis. Plasma clots formed in the presence of Tridegin lyse more rapidly when either streptokinase, tissue plasminogen activator or hementin is added 2 h after clot formation. The effect of Tridegin is markedly increased if clots are formed from platelet-rich plasma. Platelet-rich plasma clots are lysed much more slowly by the fibrinolytic enzymes used and if Tridegin is present, the rate of lysis returns almost to that of platelet- free clots. These studies indicate the important role of platelets in conferring resistance to commonly used fibrinolytic enzymes and suggest that protein cross-linking is an important step in this effect. Moreover they indicate that Tridegin, a small polypeptide, may have potential as an adjunct to thrombolytic therapy.

scholarly journals Role of SpoVA Proteins in Release of Dipicolinic Acid during Germination of Bacillus subtilis Spores Triggered by Dodecylamine or Lysozyme

2006 ◽  
Vol 189 (5) ◽  
pp. 1565-1572 ◽  
Author(s):  
Venkata Ramana Vepachedu ◽  
Peter Setlow
Keyword(s):  
Bacillus Subtilis ◽  
Small Molecules ◽  
Spore Germination ◽  
Dipicolinic Acid ◽  
Temperature Sensitive ◽  
Wild Type ◽  
Ph Optimum ◽  
Inner Membrane ◽  
Temperature Sensitive Mutants

ABSTRACT The release of dipicolinic acid (DPA) during the germination of Bacillus subtilis spores by the cationic surfactant dodecylamine exhibited a pH optimum of ∼9 and a temperature optimum of 60°C. DPA release during dodecylamine germination of B. subtilis spores with fourfold-elevated levels of the SpoVA proteins that have been suggested to be involved in the release of DPA during nutrient germination was about fourfold faster than DPA release during dodecylamine germination of wild-type spores and was inhibited by HgCl2. Spores carrying temperature-sensitive mutants in the spoVA operon were also temperature sensitive in DPA release during dodecylamine germination as well as in lysozyme germination of decoated spores. In addition to DPA, dodecylamine triggered the release of amounts of Ca2+ almost equivalent to those of DPA, and at least one other abundant spore small molecule, glutamic acid, was released in parallel with Ca2+ and DPA. These data indicate that (i) dodecylamine triggers spore germination by opening a channel in the inner membrane for Ca2+-DPA and other small molecules, (ii) this channel is composed at least in part of proteins, and (iii) SpoVA proteins are involved in the release of Ca2+-DPA and other small molecules during spore germination, perhaps by being a part of a channel in the spore's inner membrane.

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