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Storage Compounds (storage + compound)
Selected AbstractsThe Monoammoniate of Lithium Borohydride, Li(NH3)BH4: An Effective Ammonia Storage CompoundCHEMISTRY - AN ASIAN JOURNAL, Issue 6 2009Simon Abstract Store it up: The ammoniate, Li(NH3)BH4, has been prepared and fully characterized by Raman and NMR spectroscopy and X-ray powder diffraction. The potential for its use as an ammonia store and a comparison to other ammonia storage materials is discussed. Lithium borohydride absorbs anhydrous ammonia to form four stable ammoniates; Li(NH3)nBH4, mono-, di-, tri-, and tertraammoniate. This paper focuses on the monoammoniate, Li(NH3)BH4, which is readily formed on exposure of LiBH4 to ammonia at room temperature and pressure. Ammonia loss from Li(NH3)BH4 commences around 40,°C and the compound transforms directly to LiBH4. The crystal structure of Li(NH3)BH4 is reported here for the first time. Its close structural relationship with LiBH4 provides a clear insight into the facile nature and mechanism of ammonia uptake and loss. These materials not only represent an excellent high weight-percent ammonia system but are also potentially important hydrogen stores. [source] Changes in the levels of indoleamine phytochemicals during véraison and ripening of wine grapesJOURNAL OF PINEAL RESEARCH, Issue 1 2010Susan J. Murch Abstract:, Melatonin and serotonin have previously been described in mature wine grapes and finished wines, but the metabolism of these signalling molecules in the development of wine grapes has not previously been investigated. We harvested wine grapes at different stages of development from lag phase through véraison from eight different commercial vineyards representing a diversity of growing conditions, management practices, merlot varietals and localized ecosystems to determine whether different patterns in melatonin and serotonin can be found in wine grapes during seed development and berry maturation. Melatonin was detected in 45% of the fully developed purple, postvéraison grapes but only found in 23% of prelag phase samples. However, the actual concentration of melatonin was highest in wine grapes harvested at the early stage of véraison when the seed is developing. Serotonin was not detected in any of the prelag phase grapes but was consistently detected in 30,35% of grapes harvested during the véraison transition at consistent levels of about 8,10 ,g/g. Interestingly, the nitrogen storage compound ,-aminobutyric acid was also found at about 115 ,g/g in 77% of early stage green grapes and declined in both prevalence and concentration with ripening. Together, these data are indicative of a potential role for these molecules in the development and maturation of wine grapes. [source] Wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) multiple inositol polyphosphate phosphatases (MINPPs) are phytases expressed during grain filling and germination,PLANT BIOTECHNOLOGY JOURNAL, Issue 2 2007Giuseppe Dionisio Summary At present, little is known about the phytases of plant seeds in spite of the fact that this group of enzymes is the primary determinant for the utilization of the major phosphate storage compound in seeds, phytic acid. We report the cloning and characterization of complementary DNAs (cDNAs) encoding one of the groups of enzymes with phytase activity, the multiple inositol phosphate phosphatases (MINPPs). Four wheat cDNAs (TaPhyIIa1, TaPhyIIa2, TaPhyIIb and TaPhyIIc) and three barley cDNAs (HvPhyIIa1, HvPhyIIa2 and HvPhyIIb) were isolated. The open reading frames ranged from 1548 to 1554 bp and the level of homology between the barley and wheat proteins ranged from 90.5% to 91.9%. All cDNAs contained an N-terminal signal peptide encoding sequence, and a KDEL-like sequence, KTEL, was present at the C-terminal, indicating that the enzyme was targeted to and retained within the endoplasmic reticulum. Expression of TaPhyIIa2 and HvPhyIIb in Escherichia coli revealed that the MINPPs possessed a significant phytase activity with narrow substrate specificity for phytate. The pH and temperature optima for both enzymes were pH 4.5 and 65 °C, respectively, and the Km values for phytate were 246 and 334 µm for the wheat and barley recombinant enzymes, respectively. The enzymes were inhibited by several metal ions, in particular copper and zinc. The cDNAs showed significantly different temporal and tissue-specific expression patterns during seed development and germination. With the exception of TaPhyIIb, the cDNAs were present during late seed development and germination. We conclude that MINPPs constitute a significant part of the endogenous phytase potential of the developing and germinating barley and wheat seeds. [source] Quercitol and osmotic adaptation of field-grown Eucalyptus under seasonal drought stressPLANT CELL & ENVIRONMENT, Issue 7 2008STEFAN K. ARNDT ABSTRACT This study investigated the role of quercitol in osmotic adjustment in field-grown Eucalyptus astringens Maiden subject to seasonal drought stress over the course of 1 year. The trees grew in a native woodland and a farm plantation in the semi-arid wheatbelt region of south Western Australia. Plantation trees allocated relatively more biomass to leaves than woodland trees, but they suffered greater drought stress over summer, as indicated by lower water potentials, CO2 assimilation rates and stomatal conductances. In contrast, woodland trees had relatively fewer leaves and suffered less drought stress. Plantation trees under drought stress engaged in osmotic adjustment, but woodland trees did not. Quercitol made a significant contribution to osmotic adjustment in drought-stressed trees (25% of total solutes), and substantially more quercitol was measured in the leaves of plantation trees (5% dry matter) than in the leaves of woodland trees (2% dry matter). We found no evidence that quercitol was used as a carbon storage compound while starch reserves were depleted under drought stress. Differences in stomatal conductance, biomass allocation and quercitol production clearly indicate that E. astringens is both morphologically and physiologically ,plastic' in response to growth environment, and that osmotic adjustment is only one part of a complex strategy employed by this species to tolerate drought. [source] Reverse dissimilatory sulfite reductase as phylogenetic marker for a subgroup of sulfur-oxidizing prokaryotesENVIRONMENTAL MICROBIOLOGY, Issue 2 2009Alexander Loy Summary Sulfur-oxidizing prokaryotes (SOP) catalyse a central step in the global S-cycle and are of major functional importance for a variety of natural and engineered systems, but our knowledge on their actual diversity and environmental distribution patterns is still rather limited. In this study we developed a specific PCR assay for the detection of dsrAB that encode the reversely operating sirohaem dissimilatory sulfite reductase (rDSR) and are present in many but not all published genomes of SOP. The PCR assay was used to screen 42 strains of SOP (most without published genome sequence) representing the recognized diversity of this guild. For 13 of these strains dsrAB was detected and the respective PCR product was sequenced. Interestingly, most dsrAB -encoding SOP are capable of forming sulfur storage compounds. Phylogenetic analysis demonstrated largely congruent rDSR and 16S rRNA consensus tree topologies, indicating that lateral transfer events did not play an important role in the evolutionary history of known rDSR. Thus, this enzyme represents a suitable phylogenetic marker for diversity analyses of sulfur storage compound-exploiting SOP in the environment. The potential of this new functional gene approach was demonstrated by comparative sequence analyses of all dsrAB present in published metagenomes and by applying it for a SOP census in selected marine worms and an alkaline lake sediment. [source] Development and maturation of invariant NKT cells in the presence of lysosomal engulfmentEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 10 2009Tiziana Plati Abstract A defect in invariant NKT (iNKT) cell selection was hypothesized in lysosomal storage disorders (LSD). Accumulation of glycosphingolipids (GSL) in LSD could influence lipid loading and/or presentation causing entrapment of endogenous ligand(s) within storage bodies or competition of the selecting ligand(s) by stored lipids for CD1d binding. However, when we analyzed the iNKT cell compartment in newly tested LSD animal models that accumulate GSL, glycoaminoglycans or both, we observed a defective iNKT cell selection only in animals affected by multiple sulfatase deficiency, in which a generalized aberrant T-cell development, rather than a pure iNKT defect, was present. Mice with single lysosomal enzyme deficiencies had normal iNKT cell development. Thus, GSL/glycoaminoglycans storage and lysosomal engulfment are not sufficient for affecting iNKT cell development. Rather, lipid ligand(s) or storage compounds, which are affected in those LSD lacking mature iNKT cells, might indeed be relevant for iNKT cell selection. [source] Seasonal nitrogen storage and remobilization in the forb Rumex acetosaFUNCTIONAL ECOLOGY, Issue 3 2001U. Bausenwein Summary 1,The contribution of N storage and remobilization to the vegetative and reproductive growth of the forb Rumex acetosa was quantified using 15N labelling techniques with plants derived from semi-natural grasslands in Scotland. 2,The contribution of remobilized N to the total N in the new above-ground tissues was highest at the beginning of the growing season at 58%. New leaves and reproductive organs contained equal amounts of remobilized N. 3,During early vegetative growth, the taproot was the main source of remobilized N, whereas during reproductive growth, N was additionally remobilized from fine roots and leaves. 4,Free amino acids (mainly arginine and glutamine) and proteins were identified as the main storage compounds in the taproots. The protein pool did not show any seasonal variations that indicated the existence of a vegetative storage protein, indicating that such proteins are not a necessary component of N storage/remobilization in all species. 5,The ability to store and remobilize N provides a mechanism for growth in the spring when the availability of soil N is low, and means that growth depends upon environmental conditions during more than one year. [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] Differential proteomic analysis of the endoplasmic reticulum from developing and germinating seeds of castor (Ricinus communis) identifies seed protein precursors as significant components of the endoplasmic reticulumPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 9 2007Daniel J. Maltman Abstract The endoplasmic reticulum is a major compartment of storage protein and lipid biosynthesis. Maximal synthesis of these storage compounds occurs during seed development with breakdown occurring during germination. In this study, we have isolated four independent preparations of ER from both developing and germinating seeds of castor bean (Ricinus communis) and used 2-D DIGE, and a combination of PMF and MS/MS sequencing, to quantify and identify differences in protein complement at both stages. Ninety protein spots in the developing seeds are up-regulated and 19 individual proteins were identified, the majority of these are intermediates of seed storage synthesis and protein folding. The detection of these transitory storage proteins in the ER is discussed in terms of protein trafficking and processing. In germinating seed ER 15 spots are elevated, 5 of which were identified, amongst them was malate synthetase which is a component of the glyoxysome which is believed to originate from the ER. Notably no proteins involved in complex lipid biosynthesis were identified in the urea soluble ER fraction indicating that they are probably all integral membrane proteins. [source] FUSCA3 from barley unveils a common transcriptional regulation of seed-specific genes between cereals and ArabidopsisTHE PLANT JOURNAL, Issue 6 2008Miguel Ángel Moreno-Risueno Summary Accumulation of storage compounds in the embryo and endosperm of developing seeds is a highly regulated process that allows seedling growth upon germination until photosynthetic capacity is acquired. A critical regulatory element in the promoters of seed storage protein (SSP) genes from dicotyledonous species is the RY box, a target of B3-type transcription factors. However, the functionality of this motif in the transcriptional regulation of SSP genes from cereals has not been fully established. We report here the identification and molecular characterization of barley FUSCA3, a B3-type transcription factor as yet uncharacterized in monocotyledonous plants. Our results show that both the barley and Arabidopsis FUS3 genes maintain a conserved functionality for the regulation of SSP genes and anthocyanin biosynthesis in these two distantly related phylogenetic groups. Complementation of the loss-of-function mutant fus3 in Arabidopsis by the barley HvFus3 gene resulted in restored transcription from the At2S3 gene promoter and normal accumulation of anthocyanins in the seed. In barley, HvFUS3 participates in transcriptional activation of the endosperm-specific genes Hor2 and Itr1. HvFUS3, which specifically binds to RY boxes in EMSA experiments, trans -activates Hor2 and Itr1 promoters containing intact RY boxes in transient expression assays in developing endosperms. Mutations in the RY boxes abolished the HvFUS3-mediated trans -activation. HvFus3 transcripts accumulate in the endosperm and in the embryo of developing seeds, peaking at mid maturation phase. Remarkably, HvFUS3 interacts with the Opaque2-like bZIP factor BLZ2 in yeast, and this interaction is essential for full trans -activation of the seed-specific genes in planta. [source] Inhibition of starch synthesis results in overproduction of lipids in Chlamydomonas reinhardtiiBIOTECHNOLOGY & BIOENGINEERING, Issue 2 2010Yantao Li Abstract Starch and neutral lipids are two major carbon storage compounds in many microalgae and plants. Lipids are more energy rich and have often been used as food and fuel feedstocks. Genetic engineering of the lipid biosynthesis pathway to overproduce lipid has achieved only limited success. We hypothesize that through blocking the competing pathway to produce starch, overproduction of neutral lipid may be achieved. This hypothesis was tested using the green microalga Chlamydomonas reinhardtii and its low starch and starchless mutants. We discovered that a dramatic increase in neutral lipid content and the neutral lipid/total lipid ratio occurred among the mutants under high light and nitrogen starvation. BAFJ5, one of the mutants defective in the small subunit of ADP-glucose pyrophosphorylase, accumulated neutral and total lipid of up to 32.6% and 46.4% of dry weight (DW) or 8- and 3.5-fold higher, respectively, than the wild-type. These results confirmed the feasibility of increasing lipid production through redirecting photosynthetically assimilated carbon away from starch synthesis to neutral lipid synthesis. However, some growth impairment was observed in the low starch and starchless mutants, possibly due to altered energy partitioning in PSII, with more excitation energy dissipated as heat and less to photochemical conversion. This study demonstrated that biomass and lipid production by the selected mutants can be improved by physiological manipulation. Biotechnol. Bioeng. 2010;107: 258,268. © 2010 Wiley Periodicals, Inc. [source] | |||||||||||||