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81.
Ayaaki Ishizaki Tomoko Ueda Kenji Tanaka Peter F. Stanbury 《Biotechnology letters》1992,14(7):599-604
Summary The growth, substrate utilisation and L-lactate production ofLactococcus lactis IO-1 were examined on xylose, and glucose and xylose media. The yield of lactate on xylose was 0.47 g lactate/g xylose at an initial xylose concentration of 51.2 g/l and the max was 0.72 h–1. Xylose cultures were more susceptible to lactate inhibition than were glucose cultures but showed similar kinetic behaviour. The organism was capable of complete sugar utilisation when grown on a mixture of 20 g/l xylose and 20 g/l glucose and synthesised 0.66 g lactate/g sugar. 相似文献
82.
GM1-gangliosidosis (genetic beta-galactosidase deficiency): identification of four mutations in different clinical phenotypes among Japanese patients 总被引:4,自引:2,他引:2
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GM1-gangliosidosis is a genetic neurological disorder caused by mutations in the lysosomal acid beta-galactosidase gene. While its phenotypic expression is complex, it is usually classified as being of infantile, juvenile, or adult form, on the basis of age at onset, the rate of symptomatic progression, and severity of central nervous system involvement. We have analyzed the acid beta-galactosidase gene in 12 Japanese patients from nine families. The aim was to identify mutations in individual patients and then to examine possible correlation between the mutations and the clinical phenotypes. Northern blotting studies with a full-length human beta-galactosidase cDNA showed that the mRNA ranged from undetectable to substantially decreased in the infantile patients but was normal in quantity and size in all juvenile and adult patients. Four distinct missense mutations have been identified, each limited to the respective clinical forms within our small-size samples. In the infantile patient with decreased but detectable mRNA, a point mutation was found resulting in Arg49----Cys. In the infantile patient with nearly undetectable mRNA, mutation Arg457----Ter was identified. The mutation Arg201----Cys was found in all four of the juvenile patients, while all six adult patients were homozygous for the point mutation Ile51----Thr. The mutations found in the juvenile and adult patients alter restriction sites in the normal gene and thus are amendable to quick screening. The prediction that these mutations are responsible for the clinical disease was confirmed by no expression of the catalytic activity of the mutant proteins in the COS-I cell expression system.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
83.
The effect of ozone exposure on the activities of reactive oxygen scavenging enzymes (SOD†, catalase, GSH-Px) in RBC of Japanese charr (Salvelinus leucomaenis) was examined. Ozone (0, 0.4 and 0.7 ppm as initial concentrations) was exposed to Japanese charr for 30 min, which definitely caused serious membrane damage to RBC of fish. Ozone exposure at 0.4 and 0.7 ppm decreased activities of both catalase and GSH-Px by 80 to 57+ of the control. On the other hand, the activities of SOD remained unaffected even by 0.7 ppm ozone exposure. A hypothesis on the RBC membrane damage and participation of SOD and heme-iron was proposed. 相似文献
84.
85.
86.
The contents of S-(1,2-dicarboxyethyl)glutathione (DCE-GS) in several tissues of rat were determined by HPLC. The peptide was present at concentrations (nmol/g tissue) of 119 in lens, 71.6 in liver, and 27.4 in heart. It was, however, not detected in spleen, kidney, cerebrum, or cerebellum. In rat liver, DCE-GS was located primarily in the cytosolic fraction. The substrates for the enzymic synthesis of DCE-GS were GSH and L-malate. In rats, the DCE-GS-synthesizing activity was found to be highest in the liver and in the cytosol of rat liver subcellular fractions. The DCE-GS-synthesizing enzyme was partially purified from rat liver cytosolic fraction by ammonium sulfate fractionation, Phenyl Superose chromatography, hydroxyapatite chromatography, and gel filtration. The molecular mass of the enzyme was estimated to be 53 kDa by gel filtration and SDS-PAGE, showing it to be a monomeric protein. The Km values for GSH and L-malate were 2.3 and 4.0 mM at 37 degrees C, respectively. The enzyme did not utilize 1-chloro-2,4-dinitrobenzene, 1,2-dichloro-4-nitrobenzene, p-nitrophenyl bromide, trans-4-phenyl-3-buten-2-one, or p-nitrobenzyl chloride, which were substrates for previously characterized glutathione S-transferases. The isolated enzyme preparation showed no fumarase activity, which supported the conclusion that the formation of DCE-GS was not the result of a nonenzymic reaction following the synthesis of fumarate from L-malate by the isolated enzyme. The N-terminal amino acid of this polypeptide was presumably blocked since no sequence was obtained by automatic sequencing after electro-blotting onto a siliconized-glass fiber (SGF) sheet. 相似文献
87.
Kenzo Yokozeki Shigeru Yamanaka Koichi Takinami Yoshio Hirose Atsuo Tanaka Kenji Sonomoto Saburo Fukui 《Applied microbiology and biotechnology》1982,14(1):1-5
Summary Lipase from Rhizopus delemar was immobilized by entrapment with photo-crosslinkable resin prepolymers or urethane prepolymers or by binding to various types of porous silica beads. The immobilized lipase preparations thus obtained were examined for their activity in converting olive oil to an interesterified fat (cacao butter-like fat), whose oleic acid moieties at 1- and 3-positions were replaced with stearic acid moieties, in the reaction solvent n-hexane. Although all of the immobilized preparations exhibited some activity, lipase adsorbed on Celite and then entrapped with a hydrophobic photo-crosslinkable resin prepolymer showed the highest activity, about 75% of that of lipase simply adsorbed onto Celite. Entrapment markedly enhanced the operational stability of lipase.Dedicated to Professor H. Holzer, Freiburg University, on his 60th birthday (June 13, 1981) 相似文献
88.
Post-embryonic development of circadian rhythm in the cricket,Gryllus bimaculatus: A rhythm reversal
Kenji Tomioka Yoshihiko Chiba 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1982,147(3):299-304
Summary Locomotor activity of the male cricketGryllus bimaculatus DeGeer was recorded from the 7th or last (8th) instar nymph. The nymph showed a diurnal rhythm (nymphal rhythm = NR), while the adult, on the contrary, was nocturnal (adult rhythm = AR) (Fig. 1). This rhythm reversal occurred suddenly 3 to 5 days after the imaginal molt, almost simultaneously with the first spermatophore formation and the start of stridulation (calling song) (Fig. 2). In addition to the antiphase relationship, both rhythms also differed in the freerunning period (tau) and wave form. Tauscdd was significantly longer in NR (24.33 h) than in AR (23.91 h) (Fig. 3). AR was characterized by a sharp activity peak in each cycle, which NR, however, lacked (Fig. 1, 3, 6). On the basis of these differences, two possibilities are discussed; one is that NR and AR are separate oscillations and the other is that both are coupled to different phase points of one oscillation.Abbreviations
LD
light dark
-
DD
constant darkness
-
LL
constant light
-
NR
nymphal rhythm
-
AR
adult rhythm 相似文献
89.
Preparation of Uridine Diphosphate-N-Acetylgalactosamine from Uridine Diphosphate-N-Acetylglucosamine by Using Microbial Enzymes
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A method was developed for the large scale preparation of uridine diphosphate-N-acetylgalactosamine (UDP-GalNAc) from uridine diphosphate-N-acetylglucosamine (UDP-GlcNAc) by means of microbial enzymes. With Bacillus subtilis cell-free extract as a source of UDP-GlcNAc 4-epimerase, about 35% of the UDP-GlcNAc added was converted to UDP-GalNAc. After the residual UDP-GlcNAc was degraded to uridine triphosphate and N-acetylglucosamine-1-phosphate with a protamine-treated extract of bakers' yeast as a source of UDP-GlcNAc pyrophosphorylase, UDP-GalNAc was separated by anion-exchange column chromatography. The nucleotide was recovered by adsorption on charcoal and elution with ammoniacal ethanol. The final yield was about 100 μmol. 相似文献
90.
Kenji Fukuzawa Hisako Chida Akira Tokumura Hiroaki Tsukatani 《Archives of biochemistry and biophysics》1981,206(1):173-180
The antioxidative effect of α-tocopherol incorporated into lecithin liposomes was studied. Lipid peroxidation of liposome membranes, assayed as malondialdehyde production, was catalyzed by ascorbic acid and Fe2+. The peroxidation reaction, which did not involve the formation of singlet oxygen, superoxide, hydrogen peroxide, or a hydroxyl radical, was inhibited by α-tocopherol and a model compound of α-tocopherol, 2,2,5,7,8-pentamethyl-6-hydroxy-chroman (TMC), but not by phytol, α-tocopherylquinone, or α-tocopheryl acetate. One mole of α-tocopherol completely prevented peroxidation of about 100 moles of polyunsaturated fatty acid. Decrease in membrane fluidity by lipid peroxidation, estimated as increase of fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) embedded in the membrane, was also inhibited by α-tocopherol and TMC, reflecting their antioxidant functions. Cholesterol did not act as an antioxidant, even when incorporated in large amount into the liposome membranes, but it increased the antioxidative efficiency of α-tocopherol. When a mixture of liposomes with and without α-tocopherol was incubated with Fe2+ and ascorbic acid, α-tocopherol did not protect the liposomes not containing α-tocopherol from peroxidation. However, preincubation of the mixture, or addition of Triton X-100 allowed the α-tocopherol to prevent peroxidation of the liposomes not containing α-tocopherol. In contrast, in similar experiments, liposomes containing TMC prevented peroxidation of those without TMC without preincubation. Tocopherol in an amount so small as to exhibit only a slight antioxidative effect was oxidized when incorporated in egg lecithin liposomes, but it mostly remained unoxidized when incorporated in dipalmitoyllecithin liposomes, indicating that oxygen activated by ascorbic acid-Fe2+ does not oxidize α-tocopherol directly. Thus, decomposition of α-tocopherol may be caused by its interaction with peroxy and/or alkoxyl radicals generated in the process of lipid peroxidation catalyzed by Fe2+ and ascorbic acid. 相似文献