Hirosi Anzai

Relationships between Colony Morphotypes and Oil Tolerance in Rhodococcus rhodochrous

ABSTRACT A mucoidal strain of Rhodococcus rhodochrous was resistant to 10% (vol/vol) n-hexadecane, while its rough derivatives were sensitive. When the extracellular polysaccharide (EPS) produced by the mucoidal strain was added to cultures of the rough strains, the rough strains gained resistance ton-hexadecane. Thus, EPS confer tolerance ton-hexadecane in members of the genusRhodococcus.

Antiviral protection mechanisms mediated by ginbuna crucian carp interferon gamma isoforms 1 and 2 through two distinct interferon gamma-receptors

Fish genomes possess three type II interferon (IFN) genes, ifnγ1, ifnγ2 and ifnγ-related (ifnγrel). The IFNγ-dependent STAT signalling pathway found in humans and mice had not been characterized in fish previously. To identify the antiviral functions and signalling pathways of the type II IFN system in fish, we purified the ifnγ1, ifnγ2 and ifnγrel proteins of ginbuna crucian carp expressed in bacteria and found them to elicit high antiviral activities against crucian carp hematopoietic necrosis virus. We also cloned two distinct ifnγ receptor alpha chain (ifngr1) isoforms, 1 and 2, and stably expressed them in HeLa cells by transfecting the cells with ifngr1-1 or ifngr1-2 cDNA. When receptor transfectants were treated with the ligands in a one-ligand-one-receptor manner (ifnγ1 and ifngr1-2 or ifnγ2 and ifngr1-1), the stat1 protein was phosphorylated at both serine-727 and tyrosine-701 residues. Gel shift mobility analysis and reporter assay clearly showed that the specific ligand-receptor interaction resulted in the binding of the stat1 protein to the GAS element and enhanced transcription. Therefore, the actions of ifnγ1 and ifnγ2 were found to be mediated by a specific receptor for each signalling pathway via a stat1-dependent mechanism.

Relationships among colony morphotypes, cell-surface properties and bacterial adhesion to substrata in Rhodococcus

To elucidate the function of extracellular polysaccharide (EPS) produced by bacteria with hydrophobic surfaces we investigated relationships among colony morphotypes, cell-surface properties and bacterial adhesion to substrata in Rhodococcus. Rough strains adhered well to various materials and formed cell aggregates, while their mucoidal derivatives did so poorly. Cell surfaces of the rough strains were more hydrophobic than those of the corresponding mucoidal strains. Production of the EPS by the rough strains was far less than that by the corresponding mucoidal strains. Adhesion of the rough strains to quartz, glass or hydrocarbon was inhibited by the addition of EPS. Thus, rhodococcal EPS plays an important role in determination of the cell-surface hydrophobicity by acting as a hydrophilin, and its addition to the rough strains resulted in inhibition of their adhesion to the substrata.

Effects of alginates on the ingestion and excretion of cholesterol in the rat

The effects of three forms of alginate (free acid, sodium and calcium salts) on ingestion and excretion of cholesterol in the rat were studied. For two weeks, Male Sprague-Dawley rats were fed a cholesterol-rich diet containing 3% alginate from the brown alga Ascophyllum nodosum. The food efficiency of the three types of alginate was: Na-alginate > Ca-alginate > alginic acid. A significant increase in the weight of cecum was also observed in alginate diets. Alginate was not effective in preventing the elevation of serum total cholesterol levels, although irregularly changing patterns were observed. The cholesterol level of liver showed a tendency to decrease with alginate feeding, while fecal excretion of cholesterol increased.

Extraction of alginic acid from a Brazilian brown alga, Laminaria brasiliensis

In 1967, Joly & Oliveira described for the first time the Laminaria spp. of Brazil. These Laminaria occur in a large bed extending from the Cabo Frio region (Rio de Janeiro state) to north Espirito Santo state in depths ranging from 40 to 100 m. Quege et al. (1984) determined the biomass of these Laminaria spp. by dragging for samples.

Sugar constituents of fucose-containing polysaccharides from various Japanese brown algae

Sugar constituents of the fucose-containing polysaccharides (FCPs) from 21 species of brown algae were analyzed. FCPs were extracted with hot water (100 °C, 4 h), separated by precipitation with 20% (v:v) ethanol in the presence of 0.05 M MgCl2 to remove contaminating soluble alginate, and purified by DEAE-Sephadex column chromatography. The samples were hydrolyzed with HCI, and neutral sugar and uronic acid were separated by anion exchange chromatography. Their amounts were determined by gas-liquid chromatography. The neutral sugars in the FCPs from Ishige okamurae, Laminaria ochotensis, Myelophycus simplex, Padina arborescens and Sargassum thunbergii all contained arabinose, fucose, galactose, glucose, mannose, rhamnose and xylose residues. The FCPs from Ishige okamurae, Padina arborescens, Sargassum hemiphyllum, S. patents and S. sagamianum contained the four uronic acids, galacturonic acid, glucuronic acid, guluronic acid and mannuronic acid.

Super-Protective Child-Rearing by Japanese Bess Beetles, Cylindrocaulus patalis: Adults Provide Their Larvae with Chewed and Predigested Wood

Beetles of the family Passalidae (Coleoptera: Scarabaeoidea) are termed subsocial. The insects inhabit rotten wood as family groups consisting of the parents and their offspring. The Japanese species Cylindrocaulus patalis has the lowest fecundity among passalids because siblicide occurs among the first-instar larvae; accordingly, parental care toward the survived larva is the highest among Passalidae. To clarify the nutritional relationships between the parents and their offspring, we investigated their ability to digest three types of polysaccharides that are components of wood (cellulose and β-1,4-xylan) and fungal cell walls (β-1,3-glucan). Although carboxymethyl-cellulase activity was barely detectable, β-xylosidase, β-glucosidase, β-1,4-xylanase and β-1,3-glucanase activities were clearly detected in both adults and larvae. Because the activities of enzymes that digest β-1,3-glucan were much higher than those for degrading β-1,4-xylan, in both adults and larvae, it is concluded that they are mainly fungivorous. Furthermore, these digestive enzymatic activities in second- and third-instar larvae were much lower than they were in adults. Although all larval instars grew rapidly when fed chewed wood by their parents, larvae ceased growing and died when fed only artificially ground wood meals. We conclude that the larvae are assumed to be provided with chewed predigested wood in which β-1,3-glucan is degraded by parental enzymes.

Glycolytic Activities in the Larval Digestive Tract of Trypoxylus dichotomus (Coleoptera: Scarabaeidae)

The larvae of the Japanese horned beetle, Trypoxylus dichotomus (Coleoptera: Scarabaeidae: Dynastinae), are an example of a saprophage insect. Generally, Scarabaeid larvae, such as T. dichotomus, eat dead plant matter that has been broken down by fungi, such as Basidiomycota. It is thought that β-1,3-glucan, a constituent polysaccharide in microbes, is abundant in decayed plant matter. Studies of the degradation mechanism of β-1,3-glucan under these circumstances are lacking. In the current study, we sought to clarify the relationship between the capacity to degrade polysaccharides and the food habits of the larvae. The total activities and optimum pH levels of several polysaccharide-degrading enzymes from the larvae were investigated. The foregut, midgut and hindgut of final instar larvae were used. Enzymatic activities were detected against five polysaccharides (soluble starch, β-1,4-xylan, β-1,3-glucan, pectin and carboxymethyl cellulose) and four glycosides (p-nitrophenyl (PNP)-β-N-acetylglucosaminide, PNP-β-mannoside, PNP-β-glucoside and PNP-β-xyloside). Our results indicate that the digestive tract of the larvae is equipped with a full enzymatic system for degrading β-1,3-glucan and β-1,4-xylan to monomers. This finding elucidates the role of the polysaccharide-digesting enzymes in the larvae, and it is suggested that the larvae use these enzymes to enact their decomposition ability in the forest environment.

Changes in M:G ratios of extracted and residual alginate fractions on boiling with water the dried brown alga Kjellmaniella crassifolia (Laminariales, Phaeophyta)

Kjellmaniella crassifolia, the edible macro-brown alga in Japan contained nearly 27% of alginates of which nearly 7% was extractable from the fronds with boiling water for 6 h and the residual alginates in the frond were almost exhaustively extracted with a dilute alkali at 60 °C for 6 h. The alginates dissolved in all these extracts with both boiling water and dilute alkali were purified by fractionation with MgCl2 and alcohol.