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131.
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A late-stage phyllosoma larva of the genus Panulirus was caughtin the central Atlantic in October 2000. Nucleotide sequenceanalysis of mitochondrial 16S rDNA identified this larva asPanulirus echinatus, which has been undescribed to date. Morphologicalexamination indicated that this eighth stage larva belongedto phyllosoma species group 2, distinguishable from the otherAtlantic species of the genus but closely related to an Indo-Pacificspecies, P. penicillatus, which is in accordance with the resultsof a molecular phylogenetic analysis. 相似文献
133.
Evidence for an essential role of intradimer interaction in catalytic function of carnosine dipeptidase II using electrospray‐ionization mass spectrometry
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Nobuaki Okumura Jun Tamura Toshifumi Takao 《Protein science : a publication of the Protein Society》2016,25(2):511-522
Carnosine dipeptidase II (CN2/CNDP2) is an M20 family metallopeptidase that hydrolyses various dipeptides including β‐alanyl‐l ‐histidine (carnosine). Crystallographic analysis showed that CN2 monomer is composed of one catalytic and one dimerization domains, and likely to form homodimer. In this crystal, H228 residue of the dimerization domain interacts with the substrate analogue bestatin on the active site of the dimer counterpart, indicating that H228 is involved in enzymatic reaction. In the present study, the role of intradimer interaction of CN2 in its catalytic activity was investigated using electrospray‐ionization time‐of‐flight mass spectrometry (ESI‐TOF MS). First, a dimer interface mutant I319K was prepared and shown to be present as a folded monomer in solution as examined by using ESI‐TOF MS. Since the mutant was inactive, it was suggested that dimer formation is essential to its enzymatic activity. Next, we prepared H228A and D132A mutant proteins with different N‐terminal extended sequences, which enabled us to monitor dimer exchange reaction by ESI‐TOF MS. The D132A mutant is a metal ligand mutant and also inactive. But the activity was partially recovered time‐dependently when H228A and D132A mutant proteins were incubated together. In parallel, H228A/D132A heterodimer was formed as detected by ESI‐TOF MS, indicating that interaction of a catalytic center with H228 residue of the other subunit is essential to the enzymatic reaction. These results provide evidence showing that intradimer interaction of H228 with the reaction center of the dimer counterpart is essential to the enzymatic activity of CN2. 相似文献
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Akihiko Masui Nobuaki Fujiwara Masahiro Takagi Tadayuki Imanaka 《Biotechnology Techniques》1999,13(11):813-815
Enzymatic decomposition of gelatin layers on X-ray films and repeated utilization of enzyme for potential industrialization were investigated using thermostable alkaline protease from the alkaliphilic Bacillus sp. B21-2. The decomposition of gelatin layers at 50 °C with the mutant enzyme (Ala187 was replaced by Pro) was higher than those of the wild-type and other mutant enzymes. In the repeated experiment for every 60 min (20 U ml–1, 50 °C), the mutant enzyme could be satisfactorily used five times while three times for the wild-type enzyme. 相似文献
137.
Narumi Sugihara Takayuki Arakawa Mikae Ohnishi Koji Furuno 《Free radical biology & medicine》1999,27(11-12)
Lipid hydroperoxide (LOOH)–dependent lipid peroxidation was induced in α-linolenic acid (LNA)-loaded hepatocytes by adding Fe, Cu, V, or Cd ions at concentrations from 20 to 500 μM. The effects of structurally related flavonoids at concentrations from 10 to 500 μM on the lipid peroxidation were examined. The results with regard to each flavonoid subclass are as follows: (i) Flavonols such as myricetin, quercetin, fisetin, and kaempferol, but not morin, showed dose-dependent antioxidative activity against metal-induced lipid peroxidation at all metal concentrations. Myricetin, quercetin, and fisetin were the most effective antioxidants, although their efficacies depended on the metal ion. Kaempferol and morin had antioxidative activity equal to the other flavonols in the presence of Cu ions, but were much less effective for the other three metal ions. (ii) Flavones, luteolin, apigenin, and chrysin were antioxidative at low Fe concentrations, but were pro-oxidative at high Fe concentrations. Luteolin exhibited antioxidative activity similar to that of catechol-containing flavonols in the presence of the other three metal ions. Apigenin and chrysin also acted as pro-oxidants with V or with all metal ions, respectively. (iii) Taxifolin, a flavanone, also showed both anti- and prooxidative activity, depending on Fe concentrations, but with other metal showed only antioxidative activity ions. (iv) Epigallocatechin, a flavanol, was antioxidative with all metal ions, and its activity was similar to that of catechol-containing flavonols. The various effects of flavonoids on metal-induced lipid peroxidation in LNA-loaded hepatocytes is discussed with regard to the change in redox potential of flavonoid–metal complexes. 相似文献
138.
Nobuaki Suzuki Satoshi Okayama Hiroshi Nonaka Yota Tsuge Masayuki Inui Hideaki Yukawa 《Applied microbiology》2005,71(6):3369-3372
The engineering of Corynebacterium glutamicum is important for enhanced production of biochemicals. To construct an improved C. glutamicum genome, we developed a precise genome excision method based on the Cre/loxP recombination system and successfully deleted 11 distinct genomic regions identified by comparative analysis of C. glutamicum genomes. Despite the loss of several predicted open reading frames, the mutant cells exhibited normal growth under standard laboratory conditions. With a total of 250 kb (7.5% of the genome), the 11 genomic regions were loaded with cryptic prophages, transposons, and genes of unknown function which were dispensable for cell growth, indicating recent horizontal acquisitions to the genome. This provides an interesting background for functional genomic studies and can be used in the improvement of cell traits. 相似文献
139.
Yoshikawa M Nishiofuku M Moriya K Ouji Y Ishizaka S Kasahara K Mikasa K Hirai T Mizuno Y Ogawa S Nakamura T Maruyama H Akao N 《Parasitology international》2008,57(4):525-529
We present 3 adult cases of visceral toxocariasis from the same family, who each consumed thin slices of raw bovine liver weekly, and developed eosinophilia and multiple small lesions in their livers and lungs. Serological examinations using the larval excretory–secretory product of Toxocara canis strongly indicated infection with Toxocara species larvae. The patients responded well to treatment with albendazole. Ingestion of raw liver from paratenic animals is considered to be a common transmission route of human toxocariasis, especially in adults. 相似文献
140.
Hiroki Matsuyama Fumimasa Amaya Soshi Hashimoto Hiroshi Ueno Satoru Beppu Mitsuhiko Mizuta Nobuaki Shime Akitoshi Ishizaka Satoru Hashimoto 《Respiratory research》2008,9(1):1-13