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11.
Enzyme-dead mutations in the herpes simplex virus 1 UL12 gene that abolished its endo- and exonuclease activities only slightly reduced viral replication in cell cultures. However, the UL12 null mutation significantly reduced viral replication, suggesting that a UL12 function(s) unrelated to its nuclease activities played a major role in viral replication. In contrast, the enzyme-dead mutations significantly reduced viral neurovirulence in mice, suggesting that UL12 nuclease activities were critical for viral pathogenesis in vivo.  相似文献   
12.
The number of spermatophores inseminated in the bursa copulatrix of females of 21 species of Theclini butterflies varied from 0 to 38, a maximum much larger than reported so far. The variation of spermatophore number observed was analyzed on a phylogenetic tree recently determined, together with variation of wing colors and male mating tactics. Monandrous species tended to be sexually dimorphic in wing color and associated with male territoriality.  相似文献   
13.
Two patterns were found in the shifts of absorption peaks inspectra of intact etiolated Pharbitis cotyledons illuminatedat room temperature. One was a well-known pattern, P649C678C683C672,called the "high-intensity illumination pattern" in this study.The other, called the "low-intensity illumination pattern,"was P649C672. (Received June 16, 1976; )  相似文献   
14.
The enantioselectivity of 4‐hydroxylation of bunitrolol (BTL), a β‐adrenoceptor blocking drug, was studied in microsomes from human liver, human hepatoma (Hep G2) cells expressing CYP2D6, and lymphoblastoid cells expressing CYP2D6. Kinetics in human liver microsomes showed that the Vmax value for (+)‐BTL was 2.1‐fold that of (−)‐BTL, and that the Km value for (+)‐BTL was lower than that for the (−)‐antipode, resulting in the intrinsic clearance (Vmax/Km) of (+)‐BTL being 2.1‐fold over its (−)‐antipode. CYP2D6 (CYP2D6‐met) expressed in Hep G2 cells had a methionine residue at position 373 of the amino acid sequence and a rat‐type N‐terminal peptide (MELLNGTGLWSM) instead of the human‐type (MGLEALVPLAVIV), and showed enantioselectivity of [(+)‐BTL < (−)‐BTL] for the rate of BTL 4‐hydroxylation. In contrast, enantioselectivity [(+)‐BTL > (−)‐BTL] for Hep G2‐CYP2D6 (CYP2D6‐val) with a human‐type N‐terminal peptide that had a valine residue at 374, which corresponds to the methionine of the CYP2D6‐met variant, was the same as that for human liver microsomes. We further confirmed that CYP2D6‐met and CYP2D6‐val expressed in human lymphoblastoid cells, both of which have methionine and valine, respectively, at position 374 and a human‐type N‐terminal peptide, exhibited the same enantioselectivities as those obtained from CYP2D6‐met and CYP2D6‐val expressed in the Hep G2 cell system. These results indicate that the amino acid at 374 of CYP2D6 is one of the key factors influencing the enantioselectivity of BTL 4‐hydroxylation. Chirality 11:1–9, 1999. © 1999 Wiley‐Liss, Inc.  相似文献   
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16.
PomA, a homolog of MotA in the H+-driven flagellar motor, is an essential component for torque generation in the Na+-driven flagellar motor. Previous studies suggested that two charged residues, R90 and E98, which are in the single cytoplasmic loop of MotA, are directly involved in this process. These residues are conserved in PomA of Vibrio alginolyticus as R88 and E96, respectively. To explore the role of these charged residues in the Na+-driven motor, we replaced them with other amino acids. However, unlike in the H+-driven motor, both of the single and the double PomA mutants were functional. Several other positively and negatively charged residues near R88 and E96, namely K89, E97 and E99, were neutralized. Motility was retained in a strain producing the R88A/K89A/E96Q/E97Q/E99Q (AAQQQ) PomA protein. The swimming speed of the AAQQQ strain was as fast as that of the wild-type PomA strain, but the direction of motor rotation was abnormally counterclockwise-biased. We could, however, isolate non-motile or poorly motile mutants when certain charged residues in PomA were reversed or neutralized. The charged residues at positions 88-99 of PomA may not be essential for torque generation in the Na+-driven motor and might play a role in motor function different from that of the equivalent residues of the H+-driven motor.  相似文献   
17.
Summary A much higher incidence of alcohol flushing among Orientals in comparison to Caucasians, i.e., >50% vs 5%–10%, has been attributed to racial differences in alcohol-metabolizing enzymes. A large majority of Orientals are atypical in alcohol dehydrogenase-2 locus (ADH 2 ), and their livers exhibit significantly higher ADH activity than the livers of most Caucasians. Approximately 50% of Orientals lack the mitochondrial aldehyde dehydrogenase (ALDH2) activity, and elimination of acetaldehyde might be disturbed. We determined by means of hybridization of genomic DNA samples with allele specific oligonucleotide probes, genotypes of the ADH 2 and ALDH 2 loci in Japanese alcohol flushers and nonflushers. We found that all individuals with homozygous atypical ALDH 2 2 /ALDH 2 2 and most of those with heterozygous atypical ALDH 1 2 /ALDH 2 2 were alcohol flushers, while all subjects with homozygous usual ALDH 1 2 /ALDH 1 2 were nonflushers. Frequency of the atypical ADH 2 2 was found to be higher in alcohol flushers than in nonflushers, but the statistical significance was not established in the sample size examined.  相似文献   
18.
A new type of dendritic molecules Gd-DTPA-XDA-D1-Glc(OH), which work as a functionalized ligand coordinating gadolinium(III) ion at the center of their frameworks with two glucose moieties on the molecular surfaces, were readily synthesized with high yield. The structures were established by IR, 1H, 13C NMR, and mass spectral studies. Its bio-distribution patterns were evaluated on rats.  相似文献   
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20.
Polyoxins D, E, and F which possess 5-carboxyuracil as the nucleobase were reacted selectively with sodium bisulfite at pH 4.0 resulting in facile decarboxylation to afford corresponding 5,6-dihydrouracil-6-sulfonates and uracil type polyoxins (polyoxins L, M, and K) in good yield. The former compounds were also converted to the latter almost quantitatively with mild alkali treatment. Biological activities of the transformed compounds were described.  相似文献   
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