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Functional interactions of plastidial phosphorylase (Pho1) and starch branching enzymes (BEs) from the developing rice endosperm are the focus of this study. In the presence of both Pho1 and BE, the same branched primer molecule is elongated and further branched almost simultaneously even at very low glucan concentrations present in the purified enzyme preparations. By contrast, in the absence of any BE, glucans are not, to any significant extent, elongated by Pho1. Based on our in vitro data, in the developing rice endosperm, Pho1 appears to be weakly associated with any of the BE isozymes. By using fluorophore-labeled malto-oligosaccharides, we identified maltose as the smallest possible primer for elongation by Pho1. Linear dextrins act as carbohydrate substrates for BEs. By functionally interacting with a BE, Pho1 performs two essential functions during the initiation of starch biosynthesis in the rice endosperm: First, it elongates maltodextrins up to a degree of polymerization of at least 60. Second, by closely interacting with BEs, Pho1 is able to elongate branched glucans efficiently and thereby synthesizes branched carbohydrates essential for the initiation of amylopectin biosynthesis. [ABSTRACT FROM AUTHOR]

Starch accounts for the majority of edible carbohydrate resources generated through photosynthesis. Amylopectin is the major component of starch and is one of highest-molecular-weight biopolymers. Rapid and systematic synthesis of frequently branched hydro-insoluble amylopectin and efficient accumulation into amyloplasts of cereal endosperm is crucial. The functions of multiple starch biosynthetic enzymes, including elongation, branching, and debranching enzymes, must be temporally and spatially coordinated. Accordingly, direct evidence of protein–protein interactions of starch biosynthetic enzymes were first discovered in developing wheat endosperm in 2004, and they have since been shown in the developing seeds of other cereals. This review article describes structural characteristics of starches as well as similarities and differences in protein complex formation among different plant species and among mutant plants that are deficient in specific starch biosynthetic enzymes. In addition, evidence for protein complexes that are involved in the initiation stages of starch biosynthesis is summarized. Finally, we discuss the significance of protein complexes and describe new methods that may elucidate the mechanisms and roles of starch biosynthetic enzyme complexes. [ABSTRACT FROM AUTHOR]

Studies the absorption of inhibitory peptides to angiotensin 1-converting enzymes in hypertensive rats. Administration of Calpis sour milk containing antihypertensive peptides; Comparison of the effects of sour milk and saline on angiotensin 1-converting enzyme activity; Indication that peptides in sour milk has an antihypertensive effect.

The purpose of this study was to evaluate the shielding effectiveness of a non-toxic double layer of barium sulfate and tungsten with disclosed elemental compositions against diagnostic X-rays. Three variations of the radiation shielding material were created: one mainly composed of tungsten (mW), another mainly composed of barium sulfate (mBa), and a third composed of a blend of barium sulfate and tungsten (W/Ba). The following three types of 1.0 mm protective sheets were used to compare their shielding effectiveness: a double layer with mW upstream and mBa downstream (mW→mBa); a double layer with mBa upstream and mW downstream (mBa→mW); and W/Ba. Moreover, using experimental measurements and Monte Carlo calculations, the shielding effectiveness against 110 kVp X-rays of mBa→mW (0.495 g cm−2) was compared with the corresponding values for a commercially available lead-free protective apron (0.25 mmPb equivalent) and a 0.5 mm pure lead sheet (0.567 g cm−2). The measured and calculated shielding of a mBa→mW double layer was approximately 1% more effective than that of the reverse arrangement and of the mixture. The shielding effectiveness of mBa→mW was 93.66%, which compared with values of 87.22% for the commercially available lead-free apron and 93.86% for pure lead. In conclusion, the 1.0 mm non-toxic radiation shielding sheet having a double-layered structure with barium sulfate upstream and tungsten downstream was approximately 13% lighter than a 0.5 mm thick pure lead sheet but provided an equivalent shielding effectiveness against diagnostic X-rays. • Proof of benefits with double-layered structure (BaSO 4 upstream, W downstream). • BaSO 4 –W shield 1% better than reverse, 13% lighter than 0.5 mm lead, equal protection. • Non-toxic BaSO4–W shield combines high shielding effectiveness and safety. • Promising future for x-ray shielding techniques with optimized double-layered shield. [ABSTRACT FROM AUTHOR]

Abstract: In order to determine the conditions for the maximum performance of a fed-batch composting (FBC) reactor, polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) was used to analyze the microbial communities established under the confined conditions of moisture content and environmental temperature. To evaluate the effects of microbial community structures on the performance of FBC reactors, degradation experiments using small-scale reactors and model waste were conducted under confined environmental conditions. A high degradation rate was observed under a wide range of MC conditions (30–60%) and at higher than usual temperatures (30–50°C). The microbial communities that formed in the experimental FBC reactors were analyzed by DGGE of PCR-amplified 16S rRNA genes. The DGGE banding patterns at the same level as the degradation rates were similar even if the environmental conditions were different. Sequence analysis of the DGGE bands revealed the primary microbes which act in the reactor. [Copyright &y& Elsevier]

The unicellular red alga Galdieria sulphuraria grows efficiently and produces a large amount of biomass in acidic conditions at high temperatures. It has great potential to produce biofuels and other beneficial compounds without becoming contaminated with other organisms. In G. sulphuraria , biomass measurements and glycogen and lipid analyses demonstrated that the amounts and compositions of glycogen and lipids differed when cells were grown under autotrophic, mixotrophic, and heterotrophic conditions. Maximum biomass production was obtained in the mixotrophic culture. High amounts of glycogen were obtained in the mixotrophic cultures, while the amounts of neutral lipids were similar between mixotrophic and heterotrophic cultures. The amounts of neutral lipids were highest in red algae, including thermophiles. Glycogen structure and fatty acids compositions largely depended on the growth conditions. [ABSTRACT FROM AUTHOR]

We report a sum frequency generation (SFG) spectroscopy study of d -glucose, d -fructose and sucrose in the C H stretching vibration regime. Wetting effect on the SFG spectra was investigated. The SFG spectrum of d -glucose changed from that of α- d -glucose into those of α- d -glucose monohydrate by wetting. The SFG spectra showed evidence of a small change of β- d -fructopyranose into other anomers by wetting. SFG spectra of sucrose did not change by wetting. Assignments of the vibrational peaks in the SFG spectra of the three sugars in the dry and wet states were performed in the C H stretching vibration region near 3000 cm −1 . [ABSTRACT FROM AUTHOR]

To understand high amount of production and detailed processing of antihypertensive peptides, Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP), in Lactobacillus helveticus CM4 fermented milk, whole genome sequence of the CM4 strain was completed and compared to previously reported whole genome sequence of L. helveticus DPC4571. It revealed 2,028,493 bp of DNA sequence and encoding of 2174 open reading frames in the whole genome sequence with the highest homology to the genome sequence of L. helveticus DPC 4571. Comparative analysis focused on proteolytic enzymes between CM4 and DPC4571 strains revealed existence of 23 kinds of identical intracellular peptidase genes in both strains but no prtY type proteinase gene in DPC4571. Immunoblotting analysis with an antibody raised against the PrtY proteinase showed existence of the 45 kDa PrtY protein in CM4 but not in DPC4571 in the cell extracts. The cell wall-associated proteinase activity was higher in the CM4 than that in the DPC4571 throughout all fermentation period, and the amounts of VPP and IPP in CM4 and DPC4571 fermented milk were correlated with the proteinase activity on the cell wall. Moreover, slight difference of the β-casein hydrolysates by cell wall-associated extracellular proteinases between CM4 and DPC4571 cells was detected by a MALDI-TOF/TOF analysis. These results suggest that the extracellular proteinase activity might affect on the productivity of VPP and IPP in L. helveticus fermented milk and some peptidases might play important role in following precise processing to release VPP and IPP. [Copyright &y& Elsevier]

Abstract: Rice endosperm starch is composed of 0–30% linear amylose, which is entirely synthesized by granule-bound starch synthase I (GBSSI: encoded by Waxy, Wx). The remainder consists of branched amylopectin and is elongated by multiple starch synthases (SS) including SSI, IIa and IIIa. Typical japonica rice lacks active SSIIa and contains a low expressing Wx b causing a low amylose content (ca. 20%). WAB2-3 (SS3a/Wx a ) lines generated by the introduction of a dominant indica Wx a into a japonica waxy mutant (SS3a/wx) exhibit elevated GBSSI and amylose content (ca. 25%). The japonica ss3a mutant (ss3a/Wx b ) shows a high amylose content (ca. 30%), decreased long chains of amylopectin and increased GBSSI levels. To investigate the functional relationship between the ss3a and Wx a genes, the ss3a/Wx a line was generated by crossing ss3a/Wx b with SS3a/Wx a , and the starch properties of this line were examined. The results show that the apparent amylose content of the ss3a/Wx a line was increased (41.3%) compared to the parental lines. However, the GBSSI quantity did not increase compared to the SS3a/Wx a line. The amylopectin branch structures were similar to the ss3a/Wx b mutant. Therefore, Wx a and ss3a synergistically increase the apparent amylose content in rice endosperm, and the possible reasons for this increase are discussed. [Copyright &y& Elsevier]

Lactobacillus helveticus can release the antihypertensive peptides, Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP), from casein in fermented milk by a specific proteolytic system. To better understand the regulation of gene expression of the proteolytic enzymes thought to link to the processing of both antihypertensive peptides in L. helveticus, microarray analysis for whole gene expression in the presence and absence of added peptides in the fermented milk was studied. The productivity of both VPP and IPP in L. helveticus CM4 fermented milk was repressed by adding 2% quantity of Peptone as peptide mixture to the milk. Among the selected 13 amino acids, Gly, Ile, Leu, Phe, Met, Ser and Val were effective in the repression of the productivity of VPP and IPP in the fermented milk. The activity of the cell wall-associated proteinase, which may play a key role in the processing of the two antihypertensive peptides, was significantly repressed by the addition of the 2% quantity of Peptone into the fermented milk. By DNA microarray analysis it was found that prtH2 corresponding to the cell wall-associated proteinase gene, most of the endopeptidase genes such as pepE, pepO1, pepO2 and pepO3, most of the oligopeptide transporter genes, such as dppA2, dppB, dppC, dppD and dppF, most likely involved in the processing of VPP and IPP were down-regulated. These results suggest that amino acids released from milk peptides in the fermented milk might down-regulate the gene expressions of some of the proteolytic enzymes and may cause repression of the release of VPP and IPP in L. helveticus fermented milk. [ABSTRACT FROM AUTHOR]

Abstract: Lowering of the CO2 concentration in the environment induces development of a pyrenoidal starch sheath, as well as that of pyrenoid and CO2-concentrating mechanisms, in many microalgae. In the green algae Chlamydomonas and Chlorella, activity of granule-bound starch synthase (GBSS) concomitantly increases under these conditions. In this study, effects of the GBSS-defective mutation (sta2) on the development of pyrenoidal starch were investigated in Chlamydomonas. Stroma starch- and pyrenoid starch-enriched samples were obtained from log-phase cells grown with air containing 5% CO2 (high-CO2 conditions favouring stromal starch synthesis) and from those transferred to low-CO2 conditions (air level, 0.04% CO2, favouring pyrenoidal starch synthesis) for 6h, respectively. In the wild type, total starch content per culture volume did not increase during the low-CO2 conditions, in spite of the development of pyrenoidal starch, suggesting that degradation of some part of stroma starch and synthesis of pyrenoid starch simultaneously occur under these conditions. Even in the GBSS-deficient mutants, pyrenoid and pyrenoid starch enlarged after lowering of the CO2 concentration. However, the morphology of the pyrenoid starch was thinner and more fragile than the wild type, suggesting that GBSS does affect the morphology of pyrenoidal starch. Surprisingly normal GBSS activity is shown to be required to obtain the high A-type crystallinity levels that we now report for pyrenoidal starch. A model is presented explaining how GBSS-induced starch granule fusion may facilitate the formation of the pyrenoidal starch sheath. [Copyright &y& Elsevier]

Abstract: Stored starch generally consists of two d-glucose homopolymers, the linear polymer amylose and a highly branched glucan amylopectin that connects linear chains. Amylopectin structurally contributes to the crystalline organization of the starch granule in cereals. In the endosperm, amylopectin biosynthesis requires the proper execution of a coordinated series of enzymatic reactions involving ADP glucose pyrophosphorylase (AGPase), soluble starch synthase (SS), starch branching enzyme (BE), and starch debranching enzyme (DBE), whereas amylose is synthesized by AGPase and granule-bound starch synthase (GBSS). It is highly possible that plastidial starch phosphorylase (Pho1) plays an important role in the formation of primers for starch biosynthesis in the endosperm. Recent advances in our understanding of the functions of individual enzyme isoforms have provided new insights into how linear polymer chains and branch linkages are synthesized in cereals. In particular, genetic analyses of a suite of mutants have formed the basis of a new model outlining the role of various enzyme isoforms in cereal starch production. In our current review, we summarize the recent research findings related to starch biosynthesis in cereal endosperm, with a particular focus on rice. [Copyright &y& Elsevier]

Abstract: Structure and properties of pyrenoid and stroma starch were compared in Chlorella. To obtain pyrenoid starch- and stroma starch-enriched samples of high purity, we investigated the effects of the CO2 concentration and growth phase on the intracellular amount and localization of starch. In cells grown with air containing 3% CO2 (high-CO2 cells) at the log phase, starch was accumulated primarily as stroma starch. When these high-CO2 cells were transferred to low-CO2 conditions (air level, 0.04% CO2), pyrenoid and pyrenoid starch started to develop within several hours. After 12h, the amount of starch per cell had increased to about 2.5-fold of that in the high-CO2 cells, the size of starch granules drastically increased (about 2.5-fold in diameter), and the morphology changed from discoidal to cup-shaped, suggesting that the cells predominantly contained pyrenoid starch. The starch composition and chain-length distribution profile did not change so much within 12h. However, analysis of the starch with a differential scanning calorimeter demonstrated that the peak temperature of gelatinization was significantly decreased as compared with that in the high-CO2 cells. These findings suggest that pyrenoid and stroma starch have distinctive physicochemical properties that are caused by the difference in the water absorption and swelling ratio of starch granules mainly due to the difference in the morphology. [Copyright &y& Elsevier]

Abstract: The putative glgX gene encoding isoamylase-type debranching enzyme was isolated from the cyanobacterium, Synechococcus elongatus PCC 7942. The deduced amino acid sequence indicated that the residues essential to the catalytic activity and substrate binding in bacterial and plant isoamylases and GlgX proteins were all conserved in the GlgX protein of S. elongatus PCC 7942. The role of GlgX in the cyanobacterium was examined by insertional inactivation of the gene. Disruption of the glgX gene resulted in the enhanced fluctuation of glycogen content in the cells during light–dark cycles of the culture, although the effect was marginal. The glycogen of the glgX mutant was enriched with very short chains with degree of polymerization 2 to 4. When the mutant was transformed with putative glgX genes of Synechocystis sp. PCC 6803, the short chains were decreased as compared to the parental mutant strain. The result indicated that GlgX protein contributes to form the branching pattern of polysaccharide in S. elongatus PCC 7942. [Copyright &y& Elsevier]