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Storage Form (storage + form)
Selected AbstractsMaternal-effect gene Ces5/Ooep/Moep19/Floped is essential for oocyte cytoplasmic lattice formation and embryonic development at the maternal-zygotic stage transitionGENES TO CELLS, Issue 8 2010Fumi Tashiro In a search for genes specifically expressed in mouse embryonic stem cells, we identified one we called Ces5. We found that it corresponded to the Ooep gene, which was recently reported to be expressed specifically in oocytes. Mouse Ces5/Ooep, also called Moep19 or Floped, encoded a 164-amino acid protein, which was detected in the cytoplasm of developing and mature oocytes and in embryos throughout the preimplantation period. To examine its function, we carried out targeted disruption of this gene. The Ces5/Ooep -null mice were grossly normal, but the females were infertile. Although the ovaries and ovulation appeared normal, the embryos from Ces5/Ooep -null females mated with wild-type males showed developmental arrest at the two- or four-cell stage. In addition, their first cleavage was considerably delayed and often asymmetrical. Thus, Ces5/Ooep is a maternal-effect gene. By electron microscopy, we found that the eggs from Ces5/Ooep -null females lacked oocyte cytoplasmic lattices (CPLs), which have long been predicted to function as a storage form for components that are maternally contributed to the early embryo. Further analysis showed that CES5/OOEP was directly associated with the CPLs. These results indicate that CES5/OOEP is an essential component of the CPLs and is required for embryonic development at the maternal-zygotic stage transition. [source] NAALADase (GCP II) inhibitors protect in models of amyotrophic lateral sclerosis (ALS)JOURNAL OF NEUROCHEMISTRY, Issue 2002A. G. Thomas Chronic glutamate toxicity is implicated in the pathogenesis of ALS. The neuropeptide N-acetyl-aspartyl glutamate (NAAG) appears to function both as a storage form for glutamate and as a neuromodulator at glutamatergic synapses. Catabolism of NAAG by N-acetylated-,-linked acidic dipeptidase (NAALADase; also termed glutamate carboxypeptidase II), yields N-acetyl aspartate (NAA) and glutamate. Since prior studies demonstrate an up-regulation of NAALADase in motor cortex and increased levels of NAA and glutamate in the CSF of ALS patients, we hypothesized that inhibition of NAALADase could protect against neuronal degeneration in ALS. Neuroprotective effects of two NAALADase inhibitors were assessed. 2-(Phosphonomethyl)pentanedioic acid (2-PMPA) decreased motor neuron loss and prevented loss of choline acetyltransferase (ChAT) activity in an in vitro model of ALS wherein chronic glutamate toxicity was induced by blocking glutamate transport. Gross morphology was preserved in 2-PMPA-treated cultures. In a SOD-1 transgenic mouse model of ALS, oral administration of a structurally different NAALADase inhibitor (GPI 5693) increased survival by 29 days and delayed onset of clinical symptoms by 17 days. Preliminary analysis of spinal cord pathology revealed severe neuronal depletion and astrocytosis with white matter changes in control mice. In mice treated with GPI 5693, normal neuronal populations with modest vacuolar changes were observed. These data suggest that NAALADase inhibition may provide an exciting therapeutic approach to the devastating disease, ALS. [source] Retinoic Acid Homeostasis: Retinoic Acid Regulates Liver Retinol Esterification As Well As Its Own Catabolic Oxidation in LiverNUTRITION REVIEWS, Issue 12 2001George Wolf D.Phil Retinol is stored in liver in the form of its esters. The retinol-esterifying enzyme lecithimretinol acyltransferase (LRAT) catalyzes the conversion of retinol into its storage form. Expression of the LRAT mRNA is induced by retinoic acid (RA), or by dietary vitamin A, and is downregulated upon vitamin A depletion. RA also induces the expression in liver of the mRNA for CYP26, the enzyme that disposes of excess RA by oxidizing RA to 4-oxo-RA. CYP26 is downregulated upon vitamin A depletion. [source] The synergistic effects of sugar and abscisic acid on myo -inositol-1-phosphate synthase expressionPHYSIOLOGIA PLANTARUM, Issue 4 2002Kaoru T. Yoshida 1L- myo -inositol-1-phosphate [Ins(1)P1] synthase (EC 5.5.1.4) catalyses the formation of Ins(1)P1 from glucose-6-phosphate, the first step in the biosynthesis of myo -inositol. Ins(1)P1 is a precursor of phytin (inositol hexakisphosphate), a storage form of phosphate and cations in seeds. Since sucrose and abscisic acid (ABA) are known to affect synthesis of storage compounds in seeds, we investigated the effects of ABA and sucrose on Ins(1)P1 synthase gene (RINO1) expression in cultured cells derived from the scutellum of mature rice seeds. Higher levels of RINO1 transcript accumulation were evident after treatment with either sucrose (10,100 mM) or ABA (10,8M to 10,4M). Glucose was also effective in the upregulation, whereas mannitol was not, suggesting that sucrose and glucose acted as metabolizable sugars and not as osmotica. Treatment with ABA and sucrose together resulted in much higher levels of transcript accumulation, suggesting a synergistic induction of the Ins(1)P1 synthase gene. [source] Generation of stable ,low phytic acid' transgenic rice through antisense repression of the 1d - myo -inositol 3-phosphate synthase gene (RINO1) using the 18-kDa oleosin promoterPLANT BIOTECHNOLOGY JOURNAL, Issue 1 2009Mio Kuwano Summary Phytic acid acts as the major storage form of phosphorus in plant seeds and is poorly digested by monogastric animals. The degradation of phytic acid in animal diets is necessary to overcome both environmental and nutritional issues. The enzyme 1d - myo -inositol 3-phosphate [Ins(3)P1] synthase (EC 5.5.1.4) catalyses the first step of myo -inositol biosynthesis and directs phytic acid biosynthesis in seeds. The rice Ins(3)P1 synthase gene (RINO1) is highly expressed in developing seed embryos and in the aleurone layer, where phytic acid is synthesized and stored. In rice seeds, 18-kDa oleosin (Ole18) is expressed in a seed-specific manner, and its transcripts are restricted to the embryo and the aleurone layer. Therefore, to effectively suppress phytic acid biosynthesis, antisense RINO1 cDNA was expressed under the control of the Ole18 promoter, directing the same spatial pattern in seeds as RINO1 in transgenic rice plants. The generated transgenic rice plants showed strong ,low phytic acid' (lpa) phenotypes, in which seed phytic acid was reduced by 68% and free available phosphate was concomitantly increased. No negative effects on seed weight, germination or plant growth were observed. The available phosphate levels of the stable transgenic plants surpassed those of currently available rice lpa mutants. [source] Structure of Debaryomyces castellii CBS 2923 phytaseACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 4 2009M. Ragon Phytate (myo -inositol hexakisphosphate) is the primary storage form of phosphate in seeds and legumes (Reddy et al., 1982). Phytases are phosphatases that hydrolyze phytate to less phosphorylated myo -inositol derivatives and inorganic phosphate. The crystal structure of phytase from Debaryomyces castellii has been determined at 2.3,Å resolution. The crystals belonged to space group P6522, with unit-cell parameters a = 121.65, c = 332.24,Å. The structure was solved by molecular replacement and refined to a final R factor of 15.7% (Rfree = 20.9%). The final model consists of a dimer (with two monomers of 458 residues), five NAG molecules and 628 water molecules. [source] Empirical investigation of price setting and quantity surcharges in the German food sectorAGRIBUSINESS : AN INTERNATIONAL JOURNAL, Issue 3 2009Awudu Abdulai In this study, the authors examined the incidence and determinants of quantity price discounts and quantity price surcharges in the German food sector through a bivariate probit model, using recent consumer scanner survey data. Selectivity bias was corrected for in estimating the magnitude of quantity price surcharges and quantity price discounts, using Heckman's procedure. The findings reveal that almost 10% of the investigated products attract higher unit prices for larger package sizes, although the extent of price surcharges varied among product categories. Quantity price discounts were found to dominate in the firms' pricing strategies. The econometric results showed that the number of package sizes, the average package size, the packaging and storage forms, as well as the price image of a product are all significant determinants of the decision to impose both quantity price surcharges and quantity price discounts. [JEL classification: D40, L11] © 2009 Wiley Periodicals, Inc. [source] | ||||||||||