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941.
942.
Makaoto Goto Osamu Imamura Junro Kuromitsu Takehisa Matsumoto Yukako Yamabe Yoshiki Tokutake Noriyuki Suzuki Brian Mason Dennis Drayna Minoru Sugawara Masanobu Sugimoto Y. Furuichi 《Human genetics》1997,99(2):191-193
The profile of helicase gene mutations was studied in 89 Japanese Werner’s syndrome (WRN) patients by examining the previously
described mutations 1– 4 as well as a new mutation found during this study, designated mutation 5. Of 178 chromosomes (89
patients), 89 chromosomes (50%) had mutation 4, 11 (6.2%) chromosomes had mutation 1, and two chromosomes (1.1%) contained
mutation 5. Mutations 2 and 3 were not observed in this patient population. The remaining 76 (42.7%) chromosomes had none
of these mutations. A significant fraction of all patients (22 total patients, 24.7%) appear to be compound heterozygotes,
including those carrying mutations of both types 1 and 4. The genotype analysis of the markers surrounding the WRN helicase gene strongly suggests that most of the chromosomes carrying either mutation 1 or 4 were derived from two single
founders.
Received: 25 July 1996 / Revised: 20 September 1996 相似文献
943.
Kazuo Fujita Kunio Watanabe Tri Heru Widarto Bambang Suryobroto 《Primates; journal of primatology》1997,38(3):233-245
A series of work by the first author have demonstrated that many macaque species show a visual preference for the pictures
of their own species when the monkeys actively press a lever to see the pictures. We expanded this study to Sulawesi macaques
kept as a pet by local people with slight modification. All seven species of Sulawesi macaques were passively exposed to a
variety of colored slides of Sulawesi macaques. The experimenter recorded the duration of visual fixation onto the pictures.
Male monkeys of all the seven species clearly watched the pictures of their own species for longer duration than those of
the other species. Such visual preference suggested that the seven Sulawesi macaques discriminate each other species and,
thus, they may not be integrated into fewer number of species. This visual preference may work to prevent overall intergradation
of the Sulawesi macaques who sometimes have hybrid zones only in limited areas. This preference was in general weaker in female
monkeys. In one species,Macaca ochreata, females actively avoided to see the pictures of conspecifics. These results may be related to how female monkeys interact
with other individuals. 相似文献
944.
Genetic variation in the synthesis of halogenated secondary metabolites in the Japanese marine red alga Laurencia nipponica Yamada (Rhodomelaceae, Ceramiales) has been investigated in laboratory crossing experiments and chemical analyses, F1 tetrasporophytes and F1 gametophytes resulting from crosses within chemical races produced major metabolites characteristic of these races. F1 tetrasporophytes derived from reciprocal interracial crosses produced: (i) both parental types of secondary metabolites; (ii) either of the parental types; or (iii) a further major compound in addition to both parental types or in addition to either of the parental types. The latter cases suggest that hybrid-specific products were formed by the combined enzymatic complements of the parents, as F1 gametophytes derived from these interracial F1 tetrasporophytes yielded one or other of their parental products in an approximate 1:1 ratio. The population structure was analyzed at localities in Hokkaido, where two of the chemical races occur sympatrically. At Usujiri (Minami-kayabe), where the prepacifenol race and the laureatin race were sym-patric, hybrid gametophytes (recombination type) were found in high frequency in addition to hybrid tetra sporophytes, which strongly suggests that a new, pre-pacifenol/laureatm race is beginning to be produced by natural hybridization and recombination. By contrast, at Oshoro Bay, where the laurencin race and the epi-lauraliene race grew together, the interracial hybrids were rare: only a few tetrasporophytes (probably F1 generation) were found, suggesting that racial integrity may be retained by habitat segregation and/or the absence of recombination-type gametophytes. 相似文献
945.
Eclosion hormone is an insect neuropeptide that consists of 62 amino acid residues including three disulfide bonds. We have previously reported its hypothetical 3D structure consisting mainly of three alpha-helices. In this paper, we report the effects of chaperone proteins on the refolding of denatured eclosion hormone in a redox buffer containing reduced and oxidized glutathione. Urea-denatured eclosion hormone was spontaneously reactivated within 1 min with a yield of more than 90%, while beta-mercaptoethanol-denatured eclosion hormone was reactivated in a few minutes with a yield of 75%. Under the same experimental conditions, eclosion hormone treated with beta-mercaptoethanol and urea was reactivated slowly with a yield of 47% over a period of 2 h. Protein disulfide isomerase, a eucaryotic chaperone protein, markedly increased the reactivation yield and rate of the totally denatured hormone. GroE oligomers slightly improved the reactivation yield but peptidyl prolyl isomerase had no influence on yield or rate. We propose that the folding pathway of eclosion hormone involves at least two rate-limiting steps, and that protein disulfide isomerase is likely to be involved in the folding in insect neuronal cells. 相似文献
946.
M Doi S Fujita Y Katsuya M Sasaki T Taniguchi H Hasegawa 《Archives of biochemistry and biophysics》2001,395(1):85-93
Despite intensive efforts, the structures of gramicidin S (GS) [cyclo(-Val-Orn-Leu-d-Phe-Pro-)(2)] and its analogues have not been elucidated by the X-ray diffraction method, except for the GS-urea complex (Hull et al., Nature 275, 206-207, 1978; Tishchenko et al., Acta Cryst. D53, 151-159, 1997). We focused on the acetylation of GS to obtain suitable crystals for X-ray diffraction. The amino groups of Orn residues were capped with trichloroacetic and m-bromobenzoic acids. Both trichloroacetyl and m-bromobenzoyl GSs (TcGS and BzGS, respectively) are hydrophobic and their properties are similar to those of acetyl-GS (AcGS). Although it is well known that AcGS yields hexagonal crystals, TcGS and BzGS yield monoclinic and orthorhombic crystals in aqueous dimethylformamide solution, respectively. Their cell volumes were approximately one-fourth or one-eighth of the hexagonal cell volume. The crystal structures of TcGS and BzGS were determined as the first examples of acetylated GS analogues: TcGS, C(64)H(90)N(12)O(12)Cl(6). 3(C(3)H(7)NO), M(r) = 1651.47, monoclinic, P2(1), a = 15.4366(6) A, b = 18.5312(4) A, c = 16.4774(6) A, beta = 14.160(2) degrees, V = 4300.6(2) A(3), Z = 2; and BzGS, C(64)H(98)N(12)O(12)Br(2). 1.54(H(2)O), M(r) = 1535.21, orthorhombic, P2(1)2(1)2(1), a = 16.748(10) A, b = 18.834(5) A, c = 28.558(10) A, V = 9008(7) A(3), Z = 4. Both these peptide molecules formed an antiparallel pleated beta-sheet, and pseudo twofold symmetries existed in the repeated sequence. beta-Turns formed at the fragments of d-Phe-Pro were classified into type II' based on their characteristics. The peptide conformations of TcGS and BzGS were similar to each other, and these structural features agreed with those of structures proposed by the previous studies. 相似文献
947.
Teiji Takechi Katsuhisa Koizumi Atsushi Azuma Masakazu Fukushima Katsutoshi Kobayashi Shinya Oda Katsuhiko Yanaga Leon Mullenders Peter Karran Masatsugu Ueda Yoshito Terai Minoru Ueki Masaru Sakamoto Aako Kondo Kiyohiko Miyake Yauko Koyamatsu Tsukasa Akiya Makoto Nakano Hiroshi Iwabuchi Tetsuya Muroya Yoshio Tenjin Kazunori Ochiai Tadao Tanaka Kyosuke Ymada Kazu Ueda Akihiko Misawa Aikou Okamoto Eizo Kimura Makoto Yasuda 《Human cell》2004,17(2):16-21
948.
M Izumikawa M Murata K Tachibana T Fujita H Naoki 《European journal of biochemistry》2000,267(16):5179-5183
Okadaic acid is a metabolite of the unicellular algae dinoflagellate. Its biosynthesis has attracted considerable attention since the skeletal structure was shown to be synthesized via an unprecedented route. However, its relevant intermediates or enzymes are unknown. In the course of our previous investigations on the oxygen source of okadaic acid by tandem mass spectrometry (CID MS/MS), we determined the level of 18O incorporation for each oxygen site from 18O2 and [18O2]acetate. In the present study, we examined H218O-labelling patterns of okadaic acid from dinoflagellates in comparison with salinomycin from actinomycetes and has provided intriguing information regarding biosynthesis. Unexpectedly, oxygen atoms originating from acetate were not labelled from H218O; this can not be accounted for by the usual metabolic route where acetyl-CoA is biosynthesized via pyruvate. Similar experiments for salinomycin revealed that all of its oxygen atoms derived from acetate or propionate were labelled by H218O. Another interesting feature is that two oxygen sites were derived from both O2 and H2O while the others were labelled only from O2. These results imply that an oxidation mechanism other than those in actinomycetes polyethers may be involved in the biosynthesis of okadaic acid. 相似文献
949.
S Rahman Y Nakamura Z Li B Clarke N Fujita Y Mukai M Yamamoto A Regina Z Tan S Kawasaki M Morell 《Génome》2003,46(3):496-506
Genes for an isoamylase-like debranching enzyme have been isolated from rice and Aegilops tauschii, the donor of the D genome to wheat. The structures of the genes are very similar to each other and to the maize SU1 isoamylase gene and consist of 18 exons spread over approximately 7.5 kb. Southern analysis and fluorescent in situ hybridization showed the Ae. tauschii gene to be located in the proximal region of the short arm of chromosome 7D, thus showing synteny with the localization of the rice isoamylase gene on rice chromosome 8. Analysis of the expression pattern of wheat sugary isoamylase genes indicates that they are strongly expressed in the developing endosperm 6 days after flowering. Three distinct Sugary-type cDNA sequences were isolated from the wheat endosperm that are likely to correspond to the products of the three genomes. The deduced amino acid sequence of rice and wheat Sugary-type isoamylase is compared with other sequences available in the database and the results demonstrate that there are three types of isoamylase sequences in plants: those containing 18 exons (the Sugary-type isoamylase gene), those containing 21 exons, and those containing only 1 exon. It is possible that different combinations of isoamylase genes are expressed in different tissues. 相似文献
950.
Engineering of Polyploid Saccharomyces cerevisiae for Secretion of Large Amounts of Fungal Glucoamylase
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Keisuke Ekino Hiroyuki Hayashi Masahiro Moriyama Minoru Matsuda Masatoshi Goto Sadazo Yoshino Kensuke Furukawa 《Applied microbiology》2002,68(11):5693-5697
We engineered Saccharomyces cerevisiae cells that produce large amounts of fungal glucoamylase (GAI) from Aspergillus awamori var. kawachi. To do this, we used the δ-sequence-mediated integration vector system and the heat-induced endomitotic diploidization method. δ-Sequence-mediated integration is known to occur mainly in a particular chromosome, and the copy number of the integration is variable. In order to construct transformants carrying the GAI gene on several chromosomes, haploid cells carrying the GAI gene on different chromosomes were crossed with each other. The cells were then allowed to form spores, which was followed by dissection. Haploid cells containing GAI genes on multiple chromosomes were obtained in this way. One such haploid cell contained the GAI gene on five chromosomes and exhibited the highest GAI activity (5.93 U/ml), which was about sixfold higher than the activity of a cell containing one gene on a single chromosome. Furthermore, we performed heat-induced endomitotic diploidization for haploid transformants to obtain polyploid mater cells carrying multiple GAI genes. The copy number of the GAI gene increased in proportion to the ploidy level, and larger amounts of GAI were secreted. 相似文献