ABSTRACT
To investigate whether the regulation of abscisic acid (ABA) content was related to germinability during grain development, two cDNAs for 9-cis-epoxycarotenoid dioxygenase (HvNCED1 and HvNCED2) and one cDNA for ABA 8'-hydroxylase (HvCYP707A1), which are enzymes thought to catalyse key regulatory steps in ABA biosynthesis and catabolism, respectively, were cloned from barley (Hordeum vulgare L.). Expression and ABA-quantification analysis in embryo revealed that HvNCED2 is responsible for a significant increase in ABA levels during the early to middle stages of grain development, and HvCYP707A1 is responsible for a rapid decrease in ABA level thereafter. The change in the embryonic ABA content of imbibing grains following dormancy release is likely to reflect changes in the expression patterns of HvNCEDs and HvCYP707A1. A major change between dormant and after-ripened grains occurred in HvCYP707A1; the increased expression of HvCYP707A1 in response to imbibition, followed by a rapid ABA decrease and a high germination percentage, was observed in the after-ripened grains, but not in the dormant grains. Under field conditions, HvNCED2 showed the same expression level and pattern during grain development in 2002, 2003, and 2004, indicating that HvNCED2 expression is regulated in a growth-dependent manner in the grains. By contrast, HvNCED1 and HvCYP707A1 showed a different expression pattern in each year, indicating that the expression of these genes is affected by environmental conditions during grain development. The varied expression levels of these genes during grain development and imbibition, which would have effects on the activity of ABA biosynthesis and catabolism, might be reflected, in part, in the germinability in field-grown barley.
Subject(s)
Abscisic Acid/metabolism , Germination/physiology , Hordeum/growth & development , Seeds/growth & development , Cytochrome P-450 Enzyme System/genetics , Cytochrome P-450 Enzyme System/physiology , Dioxygenases , Gene Expression Regulation, Developmental , Gene Expression Regulation, Plant , Genes, Plant , Hordeum/genetics , Hordeum/metabolism , Mixed Function Oxygenases/genetics , Mixed Function Oxygenases/physiology , Molecular Sequence Data , Oxygenases/genetics , Oxygenases/physiology , Plant Proteins/metabolism , Seeds/metabolism , Sequence Analysis, DNA , Temperature , Time FactorsABSTRACT
We examined binding of Bifidobacterium bifidum and Lactobacillus reuteri to the carbohydrate moieties of glycolipids extracted from human enterocyte-like Caco-2 cells in this study. In binding assays to reference glycolipids of different carbohydrate compositions, B. bifidum EB102 bound strongly to gangliotetraosylceramide (asialo-GM1) and less strongly to gangliotriaosylceramide (asialo-GM2), lactosylceramide and sulfatide. The binding profile of B. bifidum EB102 was almost identical to that of L. reuteri JCM1081 described previously [Lett. Appl. Microbiol. 27 (1998) 130]. When we examined binding to neutral glycolipids extracted from Caco-2 cells, the binding profiles of B. bifidum EB102 and L. reuteri JCM1081 were very similar to that shown by peanut agglutinin (PNA). Binding of both strains to periodate-treated intestinal glycolipids was completely abolished, suggesting that the bacterial cells bind to carbohydrate moieties of the glycolipids. Furthermore, B. bifidum EB102 was found to express multiple glycolipid-binding proteinaceaous components on the cell surface. These results strongly suggested involvement of cell-surface proteinaceous components of B. bifidum in binding to the carbohydrate moieties of intestinal glycolipids recognized by PNA. Binding ability of B. bifidum and L. reuteri to intestinal glycolipids may play a crucial role for colonization on the mucosal surface of the intestine.
Subject(s)
Bifidobacterium/metabolism , Caco-2 Cells/microbiology , Carbohydrate Metabolism , Glycolipids/metabolism , Lactobacillus/metabolism , Peanut Agglutinin , Bifidobacterium/physiology , G(M1) Ganglioside , Gangliosides , Glycosphingolipids , Humans , Lactobacillus/physiologyABSTRACT
To characterize the molecular weight diversity of seed dehydrin among soybean cultivars, 26/27-kDa soybean dehydrins were purified and compared in peptide mapping patterns, partial amino acid sequences, and cryoprotective activity on enzyme. In reverse phase chromatograms of their trypsin digests, we detected several distinctive peaks, one of which was attributed to a part of the internal glycine-rich region. Partial amino acid sequences of peptide fragments from trypsin and S. aureus V8 protease cleavage were found to be identical to the Mat9 translation. The CP50 of purified 26/27-kDa dehydrins were estimated to be 0.30 and 0.11 microM, respectively.
Subject(s)
Cryoprotective Agents/chemistry , Cryoprotective Agents/pharmacology , Glycine max/chemistry , Plant Proteins/chemistry , Plant Proteins/pharmacology , Amino Acid Sequence , Animals , Cryoprotective Agents/isolation & purification , Heat-Shock Proteins/chemistry , Heat-Shock Proteins/genetics , Heat-Shock Proteins/isolation & purification , Heat-Shock Proteins/pharmacology , L-Lactate Dehydrogenase/metabolism , Molecular Sequence Data , Molecular Weight , Peptide Fragments/chemistry , Peptide Fragments/genetics , Peptide Mapping , Plant Proteins/genetics , Plant Proteins/isolation & purification , Rabbits , Seeds/chemistryABSTRACT
A sensitive method to examine the brassinolide (BL) response of barley (Hordeum vulgare L.) using dark-grown leaf segments was established based on the known method for wheat. BL responses of 53 dwarf isogenic lines of barley were examined, and two lines were found having a uzu gene that doesn't respond significantly. These results indicate that uzu dwarfism may be caused by the non-responding character to BL.
