Catalase formation in Rhodotorula mucilaginosa in relation to the effect of glucose and antibiotics

The developmental pattern of the catalase activity in Rhodotorulamucilaginosa, an obligate aerobe, was investigated in relationto its growth. The pattern of catalase activity does not runin a manner comparable with that of a respiratory capacity,because catalase activity takes a continual rise after the middleof the logarithmic growth, while a respiratory pattern runsa constant level during the corresponding growth phase. Additionof antimycin A to cells with a minimum catalase activity doesnot block the increase in the catalase activity. Chloramphenicoldoes not exert any recognizable effect on the catalase formationwhereas cycloheximide does create an intense inhibitory effect,regardless of addition times on the course of growth. Theseresults show that the synthesizing sites of yeast catalase aredifferent from mitochondria. ¹Present address: Department of Biology, Japan Women's University,Tokyo, Japan (Received February 18, 1970; )     

Some properties of NAD-independent {alpha}-glycerophosphate dehydrogenase of yeast

NAD-independent, mitochondrial -glycerophosphate dehydrogenaseof baker's yeast, Saccharomyces cerevisiae, was liberated fromcells and its nature was examined. Hydrogen acceptors, pH optimaand reaction rates with substrate and hydrogen acceptor of theenzyme were determined. A naturally occurring phenolic pigmentextracted from yeast cells was also found to function as aneffective hydrogen acceptor for the enzyme. Addition of FMNor FAD to the -glycerophosphate oxidation system largely acceleratedenzymatic activity, whereas the enzyme system was strongly blockedby SH-reagents. This suggests that the SH-group functions atan essential site. Clear-cut inhibition by antimycin A of electrontransfer to cytochrome c suggests the intermediation of cytochromeb. (Received December 13, 1968; )     

A PHENOLIC PIGMENT REACTIVE TO L-LACTATE CYTOCHROME C REDUCTASE OF YEAST

1. A phenolic pigment was extracted from baker's yeast. The pigmentis slowly autooxidizable, and rapidly oxidized with Rhus-laccaseor polyphenol oxidase and reduced by dithionite.
2. The pigmentdissolved in ethylether had an absorption peak at258 mµ,shoulders at 289 and 382 mµ and a plateauat 450–500mµ. The difference spectrum between oxidizedand reducedforms of the pigment showed a wide plateau around500 mµ.
3. The pigment supported the oxygen uptake by reconstructed enzymesystem: L-lactate, L-lactate cytochhrome c reductase and Rhuslaccaseor polyphenol oxidase. In its absence, no oxygen uptake tookplace. The pigment was replaced successfully with p-quinone,catechol and menadione, but not with ubiquinone. The sequenceof hydrogen transport can be represented: L-lactate L-lactatecytochrome c reductase "phenolic pigment" oxidase oxygen.

(Received August 11, 1967; )     

The influence of gene flow on latitudinal clines of photoperiodic adult diapause in the Drosophila auraria species-complex

Temperate species belonging to the Drosophila auraria species complex, D. auraria Peng, D. biauraria Bock & Wheeler, D. triauraria Bock & Wheeler and D. subauraria Kimura, enter reproductive diapause to pass the winter in response to short daylengths. These species from Japan showed latitudinal clines in critical daylength which is longer in populations from higher latitudes. The slopes of these clines coincided well with that of the cline which is approximately predicted from climatic data, suggesting that these clines result from adaptation of the species to the latitudinal gradient of climatic conditions. Between the mainlands and the surrounding islands of Japan, the slopes of clines did not differ significantly, but the deviation from the regression line was usually smaller in mainland populations. It is assumed that gene flow reduces the genetic variation among mainland populations and results in the development of smooth clines. In the plain of east China, D. triauraria did not show clinal variation in critical daylength, although the development of the cline is expected from climatic data. Extensive gene flow among Chinese populations is considered to prevent the development of a cline.     

Climatic adaptations in the Drosophila immigrans species group: seasonal migration and thermal tolerance

Abstract. 1. In central Japan, Drosophila curviceps Okada and Kurokawa was collected in spring and autumn but not in summer at lowlands (alt. 500–1200 m), while it was collected only in summer at highlands (1500–2000 m). Experiments on its thermal tolerance suggested that summer heat at the lowlands and winter low temperatures at the highlands were adverse to this species. It is considered that this species escapes from these extreme temperatures by undergoing seasonal migration between the lowlands and the highlands. This species had no photo-periodic diapause and bred at both lowlands and highlands.
2. D.immigrans Sturtevant was less cold-hardy but more heat-tolerant than D.curviceps. It is considered that this species is unable to overwinter outdoors at least in the study areas (i.e. alt. 500m or higher in central Japan) and its populations in these areas originate with migrants from warmer areas.
3. D.albomicans Duda, a subtropical species, was less cold-hardy but more heat-tolerant than the above two species.
4. Climatic adaptations and distributions of these species are discussed with reference to their thermal tolerance.     

WATER PERMEABILITY OF THE CELL WALL IN NITELLA

1. A method has been developed to measure the hydraulic conductivityof the wall of the internodal cell of Nitella flexilis.
2. Therate of water penetration through the cell wall varies linearlywith the hydrostatic pressure difference between the two sidesof the wall, showing that water permeability of the cell wallremains independent of the pressure difference applied.
3. Waterpermeability of the cell wall is inversely proportionalto itsthickness It is 30µµmin^–3{dot}atm^–3when the thickness of the wall is 10 µ.
4. Water permeabilityof the cell wall is the same for inward andoutward water flow.The polar water permeability of the entiremembrane system (walland protoplasmic part) of the living celldemonstrated by KAMIYAand TAZAWA (1) is, therefore, due tothe living protoplasmicpart.
5. The ratio of the inward to outward permeability constantsofthe protoplasmic layer alone is higher than that of the entiremembrane system composed of protoplasmic layer and cell wall.

¹ Dedicated to Prof. H. TAMIYA on the occasion of his 60th birthday.The present work was supported in part by a Grant-in-Aid forFundamental Scientific Research from the Ministry of Education. ² Present address: Sh?in Women's College, Kobe. (Received July 21, 1962; )     

EFFECTS OF CALCIUM AND MAGNESIUM DEFICIENCY ON THIAMINE DISTRIBUTION IN RAT BRAIN AND LIVER

Wistar rats were divided into 4 groups and the following different synthetic diets were given for 1 month: group 1, calcium- and magnesium-deficient; group 2, calcium-deficient, magnesium-sufficient; group 3, calcium-sufficient, magnesium-deficient; group 4, calcium-sufficient, magnesium-sufficient (normal diet). After 1 month on these dietary regimens, the rats were killed. In calcium-deficiency (groups 1 and 2), thiamine concentration in synaptosomal and myelin-membrane fractions in the brain had decreased and the ratio of free thiamine to total thiamine and non-protein bound thiamine amount had increased in the brain. In magnesium-deficiency (groups 1 and 3), thiamine concentration in the liver and activities of thiamine-dependent enzymes in liver had decreased. These results indicate that calcium plays a role in binding thiamine in nerve membrane structures, which have a specific role in the conduction process of nervous tissues. In contrast, magnesium has little effect on thiamine in nervous tissues but may play an important role in thiamine-dependent enzyme systems in the liver.     

Geographic variation and genetic aspects of reproductive diapause in Drosophila triauraria and D. quadraria

ABSTRACT. Geographic variation and genetic aspect of reproductive diapause were studied in Drosophila triauraria Bock & Wheeler and D. quadraria Bock & Wheeler, in relation to their quantitative response to photoperiods. D. quadraria from the subtropical region had no photoperiodic diapause. In D. triauraria strains, diapause was induced under LD 10:14 or 12:12, but not under LD 14:10 or longer photoperiods. Their diapause was induced more effectively and maintained longer by LD 10:14 than by LD 12:12. The duration of diapause was longer in a northern strain, but the diapause inducing process varied little among different geographical strains. Diapause incidence was 50% or lower in F₁ hybrids between D. triauraria and D. quadraria and backcross progenies between F₁ and D. quadraria , and about 70% in backcross progenies between F₁ and D. triauraria under LD 10:14, but very low under LD 12:12. The lower incidence of diapause in these F; and backcross progenies is assumed to be due to the less efficient induction of diapause, since once diapause was induced in them, it was maintained for a long time, especially in the backcross progenies between F₁ and D. triauraria. These experiments suggest that diapause induction and maintenance are different physiological processes controlled by different genetic systems.     

Indispensability of Iron-bound Chick Transferrin for Chick Myogenesis in Vitro

Myotrophic activity of highly purified chick transferrins (Tfs) to chick primary myogenic cells has been studied in a culture medium containing horse serum. Iron-binding to Tfs is indispensable for the activity. The removal of iron from Tfs gives rise to a complete loss of the activity and it is restored by iron-rebinding depending on the amount of bound iron. This result, combined with other physicochemical and immunological data, strongly, confirms that the myotrophic activity is exerted by the Tfs themselves, not by a contaminating material(s). It has been found that culture medium containing horse Tf which seems inadequate for the study of the biological effects of Tfs is, however, suitable for studies on chick Tfs, since horse Tf is inactive in promoting chick myogenesis. Terminal sialic acid residues are unrelated to myotrophic activity since Tfs with different numbers of residues (0, 1, and 2 moles/Tf molecule) are comprable in their activities. The mechanism of Tf action on cells and contradictions among previous papers as to the requirement of Tf for cell growth have been discussed from the viewpoint of an iron-donor with class-specificity.