Maillard reaction rate in various glassy matrices

The Maillard Reaction (MR) rate below the glass transition temperature (T(g)) for various model glassy food systems was studied at temperatures between 40 degrees C and 70 degrees C. As a sample, freeze-dried glucose and lysine systems embedded in various glassy matrices (e.g., polyvinylpyrrolodone and trehalose) were used, and the MR rate below the T(g) was compared among the various glassy matrices. The extent of MR was estimated spectrophotometrically from the optical density at 280 nm (OD(280)), and the MR rate (k(280)) was determined as a pseudo zero order reaction rate from the time course of OD(280). Although k(280) was described by the Arrhenius plot, the temperature dependence of k(280) was almost the same and the intercept was different among the matrices. From the comparison of k(280), it was suggested that the MR rate in glassy matrix was affected not only by the T(g), but also by the hydrogen bonding between MR reactants and glassy matrix.     

Early development of the self-fertilizing mangrove killifish <Emphasis Type="Italic">Rivulus marmoratus</Emphasis> reared in the laboratory

The mangrove killifish Rivulus marmoratus was reared at 25°±1°C and 17ppt salinity from 0 to 100 days after hatching (DAH), and its early development was described by examining growth and morphometric parameters, meristic characters (vertebral and fin-ray counts), bone-cartilage development, and pigmentation. Growth was isometric for preanal length, head length, snout length, body depth, pectoral-fin length, dorsal-fin length, anal-fin length, and caudal-peduncle depth. Negative allometric growth was observed in eye diameter and gape size. Meristic counts (mean±SD) for vertebrae (34.2±0.4) and dorsal- (8.6±0.5), anal- (11.4±0.5), and caudal-fin rays (30.2±0.8) were complete at 0 DAH (n=5), whereas pectoral-fin rays and pelvic-fin rays were complete by 30 DAH (14.5±0.4, n=5) and 60 DAH (4.2±0.8, n=5). Full ossification of meristic elements proceeded in the following sequence: vertebrae (by 30 DAH), caudal-, dorsal-, and anal-fin rays (by 60 DAH), pectoral-fin rays (between 60 DAH and 100 DAH), and pelvic-fin rays (by 100 DAH). Both morphological characters and meristic counts indicate that this species can be considered to be a juvenile after 9.8mm in standard length (20 DAH).     

Isolation of New <Emphasis Type="Italic">Symbiodinium</Emphasis> Strains from Tridacnid Giant Clam (<Emphasis Type="Italic">Tridacna crocea</Emphasis>) and Sea Slug (<Emphasis Type="Italic">Pteraeolidia ianthina</Emphasis>) Using Culture Medium Containing Giant Clam Tissue Homogenate

Recent molecular biological studies have revealed that some photosymbiotic invertebrates dwelling in coral reefs host several genetically different dinoflagellates, Symbiodinium species, as symbionts. However, little is known about the difference in physiologic characteristics among these symbionts living in a single host, because some Symbiodinium strains are difficult to culture in vitro. To isolate some of these Symbiodinium strains, we have developed an agar culture medium plate containing antibiotics and a giant clam tissue homogenate. Using-this medium we isolated two new Symbiodinium strains from two molluscan hosts, Tridacna crocea and Pteraeolidia ianthina, each of which hosted two different Symbiodinium strains belonging to Symbiodinium C and D, respectively. The tissue homogenate was essential for the growth of Symbiodinium D. Although it was not essential for the growth of Symbiodinium C, it did stimulate the initial growth. For the isolation of some Symbiodinium strains, isolation medium containing host homogenate is effective.     

Immunolocalization of caveolin-1 and caveolin-3 in monkey skeletal,cardiac and uterine smooth muscles

Caveolin, a 20-24 kDa integral membrane protein, is a principal component of caveolar domains. Caveolin-1 is expressed predominantly in endothelial cells, fibroblasts, and adipocytes, while the expression of caveolin-3 is confined to muscle cells. However, their localization in various muscles has not been well documented. Using double-immunofluorescence labeling and confocal laser microscopy, we examined the localization of caveolins-1 and 3 in adult monkey skeletal, cardiac and uterine smooth muscles and the co-immunolocalization of these caveolins with dystrophin, which is a product of the Duchenne muscular dystrophy gene. In the skeletal muscle tissue, caveolin-3 was localized along the sarcolemma except for the transverse tubules, and co-immunolocalized with dystrophin, whereas caveolin-1 was absent except in the blood vessels of the muscle tissue. In cardiac muscle cells, caveolins-1 and -3 and dystrophin were co-immunolocalized on the sarcolemma and transverse tubules. In uterine smooth muscle cells, caveolin-1, but not caveolin-3, was co-immunolocalized with dystrophin on the sarcolemma.     

Nuclear localization of peptidylarginine deiminase V and histone deimination in granulocytes

Peptidylarginine deiminase (PAD) deiminates arginine residues in proteins to citrulline residues Ca(2+) dependently. There are four types of PADs, I, II, III, and V, in humans. We studied the subcellular distribution of PAD V in HL-60 granulocytes and peripheral blood granulocytes. Expression of green fluorescent protein-tagged PADs in HeLa cells revealed that PAD V is localized in the nucleus, whereas PAD I, II, and III are localized in the cytoplasm. PAD V deletion mutants indicated that the sequence residues 45-74 have a nuclear localization signal (NLS). A sequence feature of this NLS is a three-lysine residue cluster preceded by a proline residue and is not found in the three other PADs. Substitution of the lysine cluster by an alanine cluster abrogated the nuclear import activity. These results suggested that the NLS is a classical monopartite NLS. HL-60 granulocytes, neutrophils, and eosinophils stained with antibody specific for PAD V exhibited distinct positive signals in the nucleus. Subcellular fractionation of HL-60 granulocytes also showed the nuclear localization of the enzyme. When neutrophils were stimulated with calcium ionophore, protein deimination occurred in the nucleus. The major deiminated proteins were identified as histones H2A, H3, and H4. The implication of PAD V in histone modifications is discussed.     

Negative regulation of platelet clearance and of the macrophage phagocytic response by the transmembrane glycoprotein SHPS-1

SHPS-1 is a receptor-type glycoprotein that binds and activates the protein-tyrosine phosphatases SHP-1 and SHP-2, and thereby negatively modulates intracellular signaling initiated by various cell surface receptors coupled to tyrosine kinases. SHPS-1 also regulates intercellular communication in the neural and immune systems through its association with CD47 (integrin-associated protein) on adjacent cells. Furthermore, recent studies with fibroblasts derived from mice expressing an SHPS-1 mutant that lacks most of the cytoplasmic region suggested that the intact protein contributes to cytoskeletal function. Mice homozygous for this SHPS-1 mutation have now been shown to manifest thrombocytopenia. These animals did not exhibit a defect in megakaryocytopoiesis or in platelet production. However, platelets were cleared from the bloodstream more rapidly in the mutant mice than in wild-type animals. Furthermore, peritoneal macrophages from the mutant mice phagocytosed red blood cells more effectively than did those from wild-type mice; in addition, they exhibited an increase both in the rate of cell spreading and in the formation of filopodia-like structures at the cell periphery. These results indicate that SHPS-1 both contributes to the survival of circulating platelets and down-regulates the macrophage phagocytic response.     

Causal relationship between the loss of RUNX3 expression and gastric cancer

Runx3/Pebp2alphaC null mouse gastric mucosa exhibits hyperplasias due to stimulated proliferation and suppressed apoptosis in epithelial cells, and the cells are resistant to growth-inhibitory and apoptosis-inducing action of TGF-beta, indicating that Runx3 is a major growth regulator of gastric epithelial cells. Between 45% and 60% of human gastric cancer cells do not significantly express RUNX3 due to hemizygous deletion and hypermethylation of the RUNX3 promoter region. Tumorigenicity of human gastric cancer cell lines in nude mice was inversely related to their level of RUNX3 expression, and a mutation (R122C) occurring within the conserved Runt domain abolished the tumor-suppressive effect of RUNX3, suggesting that a lack of RUNX3 function is causally related to the genesis and progression of human gastric cancer.     

The chaperone activity of protein disulfide isomerase is affected by cyclophilin B and cyclosporin A in vitro

To elucidate the function of protein disulfide isomerase (PDI), we screened for PDI-binding proteins in a bovine liver extract using affinity column chromatography. One of the binding proteins was identified by SDS-PAGE and N-terminal amino acid sequence analysis to be cyclophilin B (Cyp B). Use of the BIACORE system revealed that purified bovine Cyp B bound specifically to bovine PDI with a K(D) value of 1.19 x 10(-5) M. Interestingly, the binding affinity between PDI and Cyp B was strengthened by preincubation of the Cyp B with cyclosporin A (CsA), yielding a K(D) value of 3.67 x 10(-6) M. Although the interaction between PDI and Cyp B affected neither the isomerase activity of PDI nor the peptidyl-prolyl cis-trans isomerase activity of Cyp B, Cyp B increased the chaperone activity of PDI. However, the complex of Cyp B and CsA completely inhibited the chaperone activity of PDI. Thus, PDI and Cyp B appear to cooperate with each other to regulate the functional expression of proteins in vivo.     

Affinity selection of DNA-binding proteins from yeast genomic DNA libraries by improved lambda phage display vector

Phage display is a useful means of identifying and selecting proteins of interest that bind specific targets. In order to examine the potential of phage display for the genome-wide screening of DNA-binding proteins, we constructed yeast genomic libraries using lambda foo-based vectors devised in this work. After affinity selection using GAL4 UAS(G) as a probe, phages expressing GAL4 were enriched approximately 5 x 10(5)-fold from the library. Approximately 90% of polypeptides encoded in correct translation reading frames by the selected phages were known or putative polynucleotide-binding proteins. This result clearly indicates that the modified lambda phage display vector in combination with our enrichment technique has great potential for the enrichment of DNA-binding proteins in a sequence-specific manner.