Studies on the Chemical Structure of Konjac Mannan

The electrophoretically homogeneous glucomannan isolated from konjac flour was composed of d-glucose and d-mannose residues in the approximate ratio of 1: 1.6. Controlled acid hydrolysis gave 4-O-β-d-mannopyranosyl-d-mannose, 4-O-β-d-mannopyranosyl-d-glucose_T 4-O-β-d-glucopyranosyl-d-glucose(cellobiose), 4-O-β-d-glucopyranosyl-d-mannose(epicellobiose), O-β-d-mannopyranosyl-(1→4)-O-β-d-mannopyranosyl-(1→4)-d-mannose, O-β-d-glucopyranosyl- (1→4)-O-β-d-mannopyranosyl-(1→4)-d-mannose, O-β-d-mannopyranosyl-(1→4)-O-β-d-glucopy- ranosyl-(1→4)-d-mannose and O-β-d-glucopyranosyl-(1→4)-O-β-d-glucopyranosyl-(1→4)-d-mannose.     

The Photochemical Reaction of Pentachlorophenol

The chemical structure of a yellow C₁₈-compound (IV), isolated from the decomposition products of sodium pentachlorophenoxide (Na-PCP) in an aqueous solution by sunlight, has been determined by chemical and spectroscopic evidences. Some of the chemistry and the absorption spectra of IV and its related compounds containing 3-cyclohexene-1,2-dione and spiroketal structures are also described.     

Studies on the Low Temperature Fermentation

An attempt has been made to isolate the bacteria capable of accumulating amino acids during the growth at low temperature from various natural sources. A psychrophilic strain P 145 forming glutamic acid at 5°C was obtained and identified as a Brevibacterium sp. The bacterium grew in the range of 0° to 37°C and exhibited the optimum growth at 15°C. The bacterium was defined as a facultative psychrophile.

The strain strictly required methionine only at above 28°C; below this temperature it grew normally without the amino acid. When methionine was added thiamine and biotin stimulated the growth of this strain at 28°C.

With the Brevibacterium sp. P 145 isolated from soil, the effect of incubation temperature on the extracellular amino acid accumulation has been examined from cultural and enzymological points of view. The strain was found to accumulate l-glutamic acid up to 5.88 mg/ml and l-alanine 0.38 mg/ml at 5°C, whereas it formed 0.21 mg/ml of l-glutamic acid and 2.54 mg/ml of l-alanine at 28°C.

The accumulation of l-alanine in the medium at 28°C seemed to be related to the thiamine requirement of the strain. In the case of thiamine deficiency, l-alanine was the main product in the culture at 28°C. When the incubation temperature was abruptly shifted from 28° to 5°C or from 5° to 28°C, the amino acid accumulation was also changed to that of the final temperature. l-Alanine dehydrogenase existed even in the cells grown at 5°C but was not active at this low temperature. These results were in accord with the informations obtained from cultural experiments.     

Studies on Menthol Derivatives

(–)-Menthyl carbinol (1-(R)-methyl-3-(R)-hydroxymethyl-4-(S)-isopropylcyclohexane) (4) was prepared stereospecifically in good yield by treatment of formaldehyde with the Grignard reagent from (–)-menthyl chloride (2), which was prepared from (–)-menthol-(1-(R)-methyl-3-(R)-hydroxy-4-(S)-isopropylcyclohexane) (1) by chlorination using the Lucas reagent (HCl+ZnCl₂). The configuration of 4 was assigned by the chemical method.     

Mechanisms of Browning Degradation of d-Fructose in Special Comparison with d-Glucose-Glycine Reaction

Degradation mechanisms of d-fructose by the interaction with amino acids or organic acids in aqueous solution at initial pH 5.5 heated at 100°C were investigated and a substantial difference in mechanisms between fructose degradation and glucose-glycine reaction was presented. d-Fructose browned more intensely than did d-glucose in lower concentration of glycine and/or in earier stage of reaction period. By catalytic action of carboxylate anions without any condensation with amino groups, d-fructose was decomposed to 3-deoxy-d-erythrohexosulose, 5-(hydroxymelhyl)-2-furaldehyde, and a less amount of pyruval-dehyde through caramelization. It was considered that the main path of fructose degradation was 1,2-enolization but 2,3-enolization would also occur to a little extent.     

Transmission ratio distortion of molecular markers in a doubled haploid population originated from a natural hybrid between Osmunda japonica and O. lancea

In ferns, intra-gametophytic selfing occurs as a mode of reproduction where two gametes from the same gametophyte form a completely homozygous sporophyte. Intra-gametophytic selfing is considered to be prevented by lethal or deleterious recessive genes in several diploid species. In order to investigate the modes and tempo of selection acting different developmental stages, doubled haploids obtained from intra-gametophytic selfing within isolated gametophytes of a putative F1 hybrid between Osmunda japonica and O. lancea were analyzed with EST_derived molecular markers, and the distribution pattern of transmission ratio distortion (TRD) along linkage map was clarified. As the results, the markers with skewness were clustered in two linkage groups. For the two highly distorted regions, gametophytes and F2 population were also examined. The markers skewed towards O. japonica on a linkage group (LG_2) showed skewness also in gametophytes, and the TRD was generated in the process of spore formation or growth of gametophytes. Also, selection appeared to be operating in the gametophytic stage. The markers on other linkage group (LG_11) showed highest skewness towards O. lancea in doubled haploids, and it was suggested that the segregation of LG_11 were influenced by zygotic lethality or genotypic evaluation and that some deleterious recessive genes exist in LG_11 and reduce the viability of homozygotes with O. japonica alleles. It is very likely that a region of LG_11were responsible for the low frequencies of intra-gametophytic selfing in O. japonica.     

An Atypical Tubulin Kinase Mediates Stress-Induced Microtubule Depolymerization in Arabidopsis

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