Sequences of cDNAs for human salivary and pancreatic α-amylases

The nucleotide sequences of the cloned human salivary and pancreatic α-amylase cDNAs correspond to the continuous mRNA sequences of 1768 and 1566 nucleotides, respectively. These include all of the amino acid coding regions. Salivary cDNA contains 200 bp in the 5′-noncoding region and 32 in the 3′-noncoding region. Pancreatic cDNA contains 3 and 27 bp of 5′- and 3′-noncoding regions, respectively. The nucleotide sequence humology of the two cDNAs is 96% in the coding region, and the predicted amino acid sequences are 94% homologous.Comparison of the sequences of human α-amylase cDNAs with those previously obtained for mouse α-amylase genes (Hagenbuchle et al., 1980; Schibler et al., 1982) showed the possibility of gene conversion between the two genes of human α-amylase.     

Some Common Themes for Enzymes and Verbs

Enzymes are remarkable molecules which make metabolism possible. Their processing powers are considerable for not only are they catalysts they also contribute to information processing, integration, coherence and memory in the cell. This complex of attributes suggests that a complementary perspective to enzyme nature and activity is needed related to what enzymes and verbs have in common. The value of this kind of thinking is that it shifts the focus from objects and mechanisms to processes and information. In order to support this idea a number of features which enzymes and verbs share are discussed including, context-dependence, occurrence, cases, voice, mood and glue/integrative capacities. The paper concludes with some reflections on the utility of a view of enzymes as verbs.     

The first isolation of enantiomeric and meso-zeaxanthin in nature

Racemic mixtures of (3RS, 3'RS)-zeaxanthin were separated into the three optical isomers, (3R, 3'R)-zeaxanthin (1), (3R,3'S;meso)-zeaxanthin (2) and (3S,3'S)-zeaxanthin (3), by converting to their corresponding dibenzoates and by using HPLC on an optical resolution column Sumipax OA-2000. According to this procedure, it has been shown that only (1) is isolated from higher plants, shellfish, starfish, sea squirt, sea cucumber and then examined; on the other hand (1), (2) and (3) are isolated from zeaxanthin fraction of shrimp, fish and turtle examined. This is the first isolation of enantiomeric and meso-zeaxanthin in nature.     

Candida albicans and Candida parapsilosis Rapidly Up-Regulate Galectin-3 Secretion by Human Gingival Epithelial Cells

Galectin-3 is a β-galactoside-binding C-type lectin that plays an important role in innate immunity. The purpose of this study was to determine whether Candida albicans and Candida parapsilosis up-regulate galectin-3 secretion by human gingival epithelial cells and gingival fibroblasts. Ca9-22, a human gingival epithelial cell line, and human gingival fibroblasts were incubated in the presence or absence of C. albicans or C. parapsilosis without serum. Levels of secreted human galectin-3 in culture supernatants were measured by enzyme-linked immunosorbent assay. We also pretreated Ca9-22 cells with cytochalasin D (an actin polymerization inhibitor), ALLN (a calpain inhibitor) and LY294002 [a phosphatidylinositol-3 kinase (PI3K) inhibitor] to determine whether the up-regulation of galectin-3 secretion was mediated by cytoskeletal changes, protease activity, or PI3K signaling. Galectin-3 secretion was significantly and rapidly up-regulated by live C. albicans and C. parapsilosis, as well as heat-killed C. albicans. In addition, cytochalasin D, LY294002 and ALLN did not inhibit the up-regulation in galectin-3 secretion. These results suggest that both live and heat-killed C. albicans and C. parapsilosis may increase the activity of the innate immune system and invasion by other microorganisms via up-regulation of galectin-3 secretion.     

Host discrimination modulates brood guarding behaviour and the adaptive superparasitism in the parasitoid wasp Trissolcus semistriatus (Hymenoptera: Scelionidae)

Because hosts utilized by parasitoids are vulnerable to further oviposition by conspecifics, host guarding benefits female wasps. The present study aims to test whether female adults regulate brood guarding behaviour by host discrimination in a solitary parasitoid Trissolcus semistriatus by presenting an intact or parasitized host egg mass to a female adult. Virgin females without oviposition experience have host discrimination ability, which enables them to adjust the number of eggs laid in the hosts. Mating experience increases superparasitism by female adults, whereas mated females achieve a higher discrimination ability as a result of oviposition experience and show a lower superparasitism rate. As expected, females exhibit brood guard after parasitizing an intact host egg mass, whereas those females visiting a previously parasitized host egg mass, do not. Because the survival of eggs in superparasitized hosts is relatively low, regulating brood guarding behaviour by host discrimination is adaptive for female wasps.     

Mapping Approaches to Gene Identification in Humans

Although a number of human genes that cause disease have been traced through the defective product, most genetic defects are recognized only by phenotype. When the biochemical defect is unknown, a gene can be located only through molecular approaches based on coinheritance (genetic linkage) of the disease phenotype with a particular allele of a polymorphic DNA marker that has already been mapped to a specific chromosomal region. Linkage studies in affected families have already localized genes for several important diseases, including cystic fibrosis. Finding a genetic linkage in families in which a disease segregates requires that the human genetic map have a large number of polymorphic markers; when the map is dense enough, any disease gene can be located by linkage to a known marker. Many DNA segments with a high degree of polymorphism are being found and mapped as markers in normal reference pedigrees. Genetic linkage mapping has implications even broader than its application to prenatal diagnosis or therapeutic strategy; analyzing mutations in important genes will illuminate basic mechanisms in molecular biology and the early events that lead to cancer and other disorders.     

Polymorphism of T-cell receptor genes among laboratory and wild mice: Diverse origins of laboratory mice

Southern blots of genomic DNA from 23 strains of laboratory mice and 19 individual wild mice were examined for restriction fragment length polymorphisms in their loci encoding the T-cell receptors (Tcr): the constant regions of the α, β, and γ chains (C _α,C _β, andC _γ) and a variable region family of the β chain (V _β8). Only a few polymorphisms were observed for each locus in the laboratory mice after using three restriction enzymes,Bam HI,Eco RI, andHind III. All the laboratory mice examined fall into one of two types for theC _α,C _β andV _β8 loci and one of three types for theC _γ. These types are found in some of the wild mice studied, indicating that they were already present in the founder mice of laboratory mouse strains. In contrast, theTcr genes are highly polymorphic among wild mice. Analysis of the polymorphisms in these loci suggests that laboratory mice have inherited their genes not only fromMus musculus domesticus, but also from other subspecies, and much more than previously believed from Asian subspecies.     

Glutamine synthetase and glutaminase activities in various hepatoma cells

Glutamine synthetase and glutaminase activities in a series of hepatoma cells of human and rat origins were determined for comparison with normal liver tissues. Marked decrease in glutamine synthetase activity was observed in the tumor cells. Phosphate-dependent and phosphate-independent glutaminase activities were increased compared with those from normal liver tissues. Well coupled mitochondria were isolated from HuH 13 line of human hepatoma cells and human liver. Oxypolarographic tests showed that glutamine oxidation was prominent in the tumor mitochondria, while mitochondria from the liver showed a feeble glutamine oxidation. Glutamine oxidation was inhibited by prior incubation of the mitochondria with DON (6-diazo-5-oxo-L-norleucine), which inhibited mitochondrial glutaminase. These results indicate that the product of glutamine hydrolysis, glutamate, is catabolized in the tumor mitochondria to supply ATP.     

Splenic outer periarterial lymphoid sheath (PALS): An immunoproliferative microenvironment constituted by antigen-laden marginal metallophils and ED2-positive macrophages in the rat

Summary In an attempt to reveal the role of antigen-laden marginal metallophil (MM) and other macrophages in the intrasplenic immune response of a specific B-cell lineage to a thymus-independent type-2 antigen (Ficoll conjugated with fluorescein isothiocyanate), simultaneous immuno-histological observations of the involved cells were performed in the rat. By newly established methods of double or triple immunostainings, time-kinetics of the following parameters were studied and compared: (1) the antigen, (2) the specific antibody-forming cells (AFC) directed to the fluorescein-isothiocyanate determinant, (3) proliferating cells labeled with 5-bromo-2-deoxyuridine (BrdU), and (4) macrophage subpopulations recognized by monoclonal antibodies (ED2 and ED3). The antigen localized stably not only in the marginal-zone macrophages but also in the MM except around the follicular area. The increase of BrdU-positive cells was observed from day 2 up to day 4 after antigen injection mostly in the periphery of the periarterial lymphoid sheath (outer PALS), which indicated antigen-induced proliferation. As a novel finding, the majority of AFC, both BrdU-positive and -negative, were either closely associated with the antigen-laden MM, or forming cell clusters with ED2-positive macrophages in the outer PALS. In contrast, there were very few AFC in juxtaposition to antigen-free MM in the follicular area or the antigen-laden marginal zone macrophages. The results led to the proposal of a hypothesis that the antigen-laden MM together with ED2-positive macrophages constitute an immunoproliferative microenvironment for the plasmacellular reaction by accumulating the antigen-specific B-cell lineage and promoting these cells to differentiate into the AFC and to proliferate in the outer PALS.Abbreviations AFC specific antibody-forming cells - BrdU 5-bromo-2-deoxyuridine - Fic-F FITC-conjugated Ficoll - FITC fluorescein isothiocyanate - HRP horseradish peroxidase - MM marginal metallophils - MZ marginal zone - PALS periarterial lymphoid sheath - PBS phosphate-buffered saline - TI2 thymus-independent type-2