n-Octyl β-d-glucoside synthesis through β-glucosidase catalyzed condensation of glucose andn-octanol in a heterogeneous system with high glucose concentration

β-Glucosidase-catalyzed synthesis ofn-octyl β-d-glucoside through condensation was performed by mixing glucose and octanol saturated with acetate buffer at 50°C. The highest yield of synthesis, 28% based on glucose, was obtained at the total glucose concentration of 0.1 mol/1. At higher glucose concentrations, the product concentration increased but the yield decreased. The stability of the enzyme in the system was so high that, even in the free form, it could be used repeatedly for synthesis without a significant loss in its activity. The overall yield of the four consecutive batch syntheses was 58% when the initial glucose concentration was adjusted to 0.1 mol/1 for each batch.     

Identification of a Novel PNMA-MS1 Gene in Marsupials Suggests the LTR Retrotransposon-Derived PNMA Genes Evolved Differently in Marsupials and Eutherians

Two major gene families derived from Ty3/Gypsy long terminal repeat (LTR) retrotransposons were recently identified in mammals. The sushi-ichi retrotransposon homologue (SIRH) family comprises 12 genes: 11 in eutherians including Peg10 and Peg11/Rtl1 that have essential roles in the eutherian placenta and 1 that is marsupial specific. Fifteen and 12 genes were reported in the second gene family, para-neoplastic antigen MA (PNMA), in humans and mice, respectively, although their biological functions and evolutionary history remain largely unknown. Here, we identified two novel candidate PNMA genes, PNMA-MS1 and -MS2 in marsupials. Like all eutherian-specific PNMA genes, they exhibit the highest homology to a Gypsy12_DR (DR, Danio rerio) Gag protein. PNMA-MS1 is conserved in both Australian and South American marsupial species, the tammar wallaby and grey short-tailed opossum. However, no PNMA-MS1 orthologue was found in eutherians, monotremes or non-mammalian vertebrates. PNMA-MS1 was expressed in the ovary, mammary gland and brain during development and growth in the tammar, suggesting that PNMA-MS1 may have acquired a marsupial-specific function. However, PNMA-MS2 seems to be a pseudogene. The absence of marsupial orthologues of eutherian PNMA genes suggests that the retrotransposition events of the Gypsy12_DR-related retrotransposons that gave rise to the PNMA family occurred after the divergence of marsupials and eutherians.     

Consequences of Warburg Effect Conditions on Growth Parameters and CO2-Exchange Rates in Tobacco Mutants

If photorespiration is studied as increase in dry weight perplant under Warburg effect conditions, the following resultsare obtained with the tobacco mutant set derived from N. tabacumvar. Consolation: The green phenotype exhibits approximately30% more Warburg effect than the yellow-green phenotype. Treatmentwith 2% O₂ reduces the rate of the leaf area expansion in bothphenotypes. If the O₂-effect is referred to unit leaf area,the relative Warburg effects are practically the same in bothphenotypes. This phenomenon is due to the fact that under normalO₂-conditions the green phenotype exhibits a higher rate ofphotosynthesis than the yellow-green phenotype and the increasein leaf area under 2% O₂ is inhibited more strongly in the yellow-greenphenotype than in the green one. If, in the short experimentalperiod, the increase of dry weight or increase in leaf areaunder 2% O₂-partial pressure is taken as a criterion of photorespiration,the yellow phenotype shows practically no effect. However, theyellow phenotype reacts very unfavorably upon exposure to 2%O₂. This treatment inhibits its ability to perform photosynthesis,apparently irreversibly. A prolonged period of exposure to 2%O₂ also damages the photosynthetic apparatus in the green andyellow-green phenotypes. This damage, however, seems to be partlyreversible. Evidently the defective plants are characterizedby the genetic condition which belongs to the green and yellowphenotypes. (Received January 26, 1983; Accepted September 22, 1983)     

Isolation and Properties of Intact Chromoplasts from Tomato Fruits

Intact chromoplasts were isolated from tomato fruits at differentripening stages by Percoll density gradient centrifugation.The isolated chromoplast fractions were contaminated very littleby other organelles, although the fraction from fully ripenedfruits contained some mitochondria and microbodies. As the transformationof chloroplasts to chromoplasts proceeded, the density of theplastids decreased from 1.096 to 1.075 g-cm^-3 and the decreasewas related to a decrease in chlorophyll and an increase inlycopene in the plastids. (Received December 21, 1983; Accepted April 20, 1984)     

Mouse Mutant Deficient in d-Amino Acid Oxidase Activity

D-Amino acid oxidase activity in the kidney homogenates of mice of seven strains was measured to search for a mutant for this enzyme. There was a consistent sex difference in the enzyme activity in these strains: male mice showed higher levels of the enzyme activity than females. In contrast to other strains, some mice of the ddY strain did not possess enzyme activity. This trait was inheritable, and a mouse stock without enzyme activity (DAO-) was established. The allele (Dao-1c) carried by the DAO- mice was recessive and behaved as a single autosomal gene in inheritance. Heterozygous mice for this gene (Dao-1+/Dao-1c) showed nearly half the enzyme activity of the wild-type homozygotes (Dao-1+/Dao-1+), suggesting that Dao-1c is a null allele and that there is a gene dosage effect on the enzyme activity.     

Intramolecular electron-transfer reaction within a diprotein complex of cytochrome c with ferrylmyoglobin modified with diethylenetriaminepentaacetic acid

Horse heart metmyoglobins modified with diethylenetriaminepentaacetic acid, metMb(DTPA)n (n=1, 2, 4, and 5), were characterized by a MALDI-TOF mass spectrometry, amino-acid sequence analysis, and UV-Vis and CD spectroscopies. The DTPA-binding sites on metMb were Lys47, Lys50, Lys87, Lys145, and Lys147 for metMb(DTPA)5, Lys47, Lys87, Lys145, and Lys147 for metMb(DTPA)4, Lys87 and Lys145 for metMb(DTPA)2, and Lys87 for metMbDTPA, respectively. The modified metMb(DTPA)n showed cytochrome c peroxidase-like activity more efficiently than native metMb: metMb(DTPA)5>metMb(DTPA)4>metMb(DTPA)2> metMbDTPA approximately equals native metMb. The first-order rate constants for the reactions of ferrylMb(DTPA)n (n=2, 4, and 5) with reduced cytochrome c [cyt c(II)] were saturated with concentrations of cyt c(II), suggesting that the electron transfer (ET) occurs within a diprotein complex. The intramolecular ET rate constants in the diprotein complex increased with increasing the number of DTPA ions. The reactions of native ferrylMb and ferrylMbDTPA with cyt c(II) obeyed a second-order rate law. A possible ET mechanism is proposed; cyt c(II) binds the DTPA-linked anionic patch around Lys87, Lys145, and Lys147 region of ferrylMb(DTPA)n.     

Ventro-dorsal Hippocampal Pathway Gates Novelty-Induced Contextual Memory Formation

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Production of oligosaccharides by glutaraldehyde treated and immobilized beta-galactosidases fromBacillus circulans

Summary The oligosaccharide-producing activity of beta-galactosidase (beta-D-galactoside galactohydrolase, EC 3.2.1. 23) preparation ofBacillus circulans was increased from 21% to 40% after glutaraldehyde treatment or immobilization onto porous silicagel(Merckogel) by crosslinkage with glutaraldehyde.