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11.
12.
On the constancy of the evolutionary rate of cistrons 总被引:32,自引:0,他引:32
Summary The variations of evolutionary rates in hemoglobins and cytochrome c among various lines of vertebrates are analysed by estimating the variance. The observed variances appear to be larger than expected purely by chance.If the amino acid substitutions in evolution are the result of random fixation of selectively neutral or nearly neutral mutations, the evolutionary rate of cistrons can be represented by the integral of the product of mutation rate and fixation probability in terms of selective values around the neutral point. This integral is called the effective neutral mutation rate.The influence of effective population number and generation time on the effective neutral mutation rate is discussed. It is concluded that the uniformity of the rate of amino acid substitutions over diverse lines is compatible with random fixation of neutral or very slightly deleterious mutations which have some chance of being selected against during the course of substitution. On the other hand, definitely advantageous mutations will introduce significant variation in the substitution rate among lines. Approximately 10% of the amino acid substitutions of average cistrons might be adaptive and create slight but significant variations in evolutionary rate among vertebrate lines, although the uniformity of evolutionary rate is still valid as a first approximation.Contribution No. 813 from the National Institute of Genetics, Mishima, Shizuokaken 411 Japan. Aided in part by a grant-in-aid from the Ministry of Education, Japan. 相似文献
13.
Yoshio Honma Keizo Takenaga Takashi Kasukabe Motoo Hozumi 《Biochemical and biophysical research communications》1980,95(2):507-512
Human promyelocytic leukemia cells (HL-60) were induced to phagocytize, reduce NBT dye(nitroblue tetrazolium), and change into forms that were morphologically similar to mature granulocytes by retinoic acid and related retinoids, but not by the pyridyl analog of retinoic acid. Induction of differentiation could be detected after 4 days of treatment of the cells with retinoic acid at as low a dose as 4 × 10?8 M. Thus, retinoids may be used in studies on the control of cell differentiation and malignancy of human myeloid leukemia cells. 相似文献
14.
Thirteen novel deoxynivalenol-degrading bacteria are classified within two genera with distinct degradation mechanisms 总被引:3,自引:0,他引:3
Sato I Ito M Ishizaka M Ikunaga Y Sato Y Yoshida S Koitabashi M Tsushima S 《FEMS microbiology letters》2012,327(2):110-117
The mycotoxin deoxynivalenol (DON), a secondary metabolite produced by species of the plant pathogen Fusarium, causes serious problems in cereal crop production because of its toxicity towards humans and livestock. A biological approach for the degradation of DON using a DON-degrading bacterium (DDB) appears to be promising, although information about DDBs is limited. We isolated 13 aerobic DDBs from a variety of environmental samples, including field soils and wheat leaves. Of these 13 strains, nine belonged to the Gram-positive genus Nocardioides and other four to the Gram-negative genus Devosia. The degradation phenotypes of the two Gram types were clearly different; all washed cells of the 13 strains degraded 100 μg mL(-1) DON to below the detection limit (0.5 μg mL(-1)), but the conditions inducing the DON-degrading activities differed between the two Gram types. The HPLC profiles of the DON metabolites were also distinct between the two genera, although all strains produced 3-epi-deoxynivalenol. The Gram-positive strains showed DON assimilation in media containing DON as a carbon source, whereas the Gram-negatives did not. Our results suggest that aerobic DDBs are distributed within at least two phylogenetically restricted genera, suggesting independent evolution of the DON-degradation mechanisms. 相似文献
15.
FI-Carboxymethylcellulase (cmc1; family 12) is one of the endoglucanases of Aspergillus aculeatus and consists of single polypeptide chain of 221 amino acids. The cmc1 gene was expressed in Aspergillus oryzae niaD300 (niaD−) under promoter 8142. The plasmid pCMG14 carrying the cmc1 gene at PstI site was used as a source of the gene (920 bp) and Aspergillus oryzae was successfully transformed by the plasmid pNAN-cmc1 (harboring cmc1 gene). The plasmid was integrated in Aspergillus oryzae niaD300 genome at niaD locus and the transformed fungus constitutively produced very high amounts of endoglucanases when grown on glucose, maltose,
soluble starch and wheat bran. 相似文献
16.
John E. Moore Yasunori Maeda Jiru Xu B. Cherie Millar Peter H. Herold V. M. J. Browne-Lauwers Colin E. Goldsmith Anne Loughrey Paul J. Rooney J. Stuart Elborn Motoo Matsuda 《World journal of microbiology & biotechnology》2008,24(7):1227-1232
To employ 16S rDNA PCR and automated sequencing techniques to identify a collection of bacterial veterinary pathogens from
avian, equine, canine and ovine sources, that have proven difficult to identify, employing conventional cultural techniques.
Universal or “broad-range” eubacterial PCR was performed on a collection of 46 difficult-to-identify bacterial isolates originating
from clinical veterinary specimens. 16S rDNA PCR was performed using two sets of universal primers to successfully generate
a composite amplicon of 1,068 bp, which was sequenced to obtain each isolate’s identity. Sequence analysis was able to identify
all isolates examined with relative ease. Where the use of molecular identification methods is justified, such as in outbreak
control or bioterrorism in animal health, employment of partial 16S rDNA PCR and sequencing employing universal or “broad-range”
16S rDNA, provides a valuable and reliable method of identification of such pathogens. 相似文献
17.
18.
19.
Nitric Oxide Participates in the Stimulatory and Neurotoxic Action of Endothelin on Rat Striatal Dopaminergic Neurons 总被引:3,自引:0,他引:3
Hirotomo Shibaguchi Yasufumi Kataoka Shuichi Koizumi Masami Kohzuma Motoo Obana Akihiko Himeno Kimihiro Yamashita Kohtaro Taniyama 《Cellular and molecular neurobiology》1997,17(5):471-481
1. Our method of real-time monitoring of dopamine release from rat striatal slices revealed that endothelin (ET)-3-induced dopamine release was inhibited by N
G-methyl-L-arginine (L-NMMA; 1 mM), an inhibitor of nitric oxide (NO) synthase, while N
G-methyl-D-arginine (D-NMMA; 1 mM), an inactive isomer of L-NMMA, had no effect.2. The inhibition of L-NMMA (0.1 mM) became apparent when tissues were pretreated with tetrodotoxin (1 M) for 30 min and subsequently exposed to ET-3 (4 M).3. L-NMMA (0.1 and 1 mM) dose dependently protected against ET-3-triggered hypoxic/hypoglycemic impairment of striatal responses to high K+.4. Thus, NO may work as a promoter in mediation of the stimulatory and neurotoxic action of ET-3 on the striatal dopaminergic system, presumably by interacting with interneurons in the striatum. 相似文献
20.
Shibata Kenji Yano Keiichi Tanaka Takeo Matsuda Yuzuru Yamasaki Motoo 《International journal of peptide research and therapeutics》1997,4(3):167-170
Summary RES-701-1 is an endothelin B receptor (ETB) selective peptidic antagonist, which has a novel cyclic structure of microbial origin. Modification at the C-terminal free
carboxyl group of RES-701-1 by a methyl ester results in an ETA/ETB dual selective analog, which showed relatively high affinity for ETA receptor subtype, while retaining the affinity for ETB. The carboxyl-group-deleted analog with tryptamine as the C-terminal residue also showed relatively weak affinity for ETA; however, benzyl ester or amide analogs did not show remarkable affinity for ETA. It is suggested that the binding mode of RES-701-1 and its analogs is different from those of known ligands for ET receptors. 相似文献