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141.
Sato S Kurihara T Kawamoto J Hosokawa M Sato SB Esaki N 《Extremophiles : life under extreme conditions》2008,12(6):753-761
An Antarctic psychrotrophic bacterium, Shewanella livingstonensis Ac10, produces cis-5,8,11,14,17-eicosapentaenoic acid (EPA), a long-chain polyunsaturated fatty acid (LPUFA), as a component of membrane phospholipids
at low temperatures. The EPA-less mutant generated by disruption of the EPA synthesis gene becomes cold-sensitive. We studied
whether the cold sensitivity could be suppressed by supplementation of various LPUFAs. The EPA-less mutant was cultured at
6°C in the presence of synthetic phosphatidylethanolamines (PEs) that contained oleic acid at the sn-1 position and various C20 fatty acids with different numbers of double bonds from zero to five or cis-4,7,10,13,16,19-docosahexaenoic acid (DHA) at the sn-2 position. Mass spectrometric analyses revealed that all these fatty acids became components of various PE and phosphatidylglycerol
species together with shorter partner fatty acids, indicating that large-scale remodeling followed the incorporation of synthetic
PEs. As the number of double bonds in the sn-2 acyl chain decreased, the growth rate decreased and the cells became filamentous. The growth was restored to the wild-type
level only when the medium was supplemented with phospholipids containing EPA or DHA. We found that about a half of DHA was
converted into EPA. The results suggest that intact EPA is best required for cold adaptation of this bacterium. 相似文献
142.
Hosokawa T Ono F Tsuchiya K Sato I Takeyama N Ueda S Zanusso G Takahashi H Sata T Sakudo A Suguira K Baj A Toniolo A Yoshikawa Y Onodera T 《Microbiology and immunology》2008,52(1):25-29
By immunizing Prnp-knockout mice with synthetic polypeptides, a panel of mAbs directed to bovine PrP(C) was obtained. The mAb panel was characterized by the ELISA method, where synthetic polypeptides were used for epitope mapping. Different reactivity patterns were identified. The ability of these mAbs to detect abnormal PrP(Sc) in CJD cases was studied by immunohistochemistry. All mAbs were tested for PrP(Sc) in murine, bovine, monkey and human brain tissues. Three mAbs recognized the fragmented PrP epitope in our ELISA. Antibody 1D12 was strongly reactive to ovine and squirrel monkey tissues infected with a scrapie agent, although non-reactive to scrapie-infected mouse tissues. Antibody 2D8 was clearly reactive to type-2 but not type-1 CJD human tissues. Of particular interest was the reactivity of mAb 6C4 with the inner structure of Kuru plaques (peripheral pattern) in a type-2 CJD case and mAb T2, 1D12, 2B11, 2D8, 4B5 and 6G3-2 with the central area (central pattern). The fact that different anti-PrP mAbs possess distinct staining properties suggests that the PrP(c) to PrP(Sc) conversion might involve a multiple-step process. 相似文献
143.
Analysis of isozymes was carried out against wild and cultivated commercial stocks of Flammulina velutipes to analyze their genetic differences. Esterase isozymes from F. velutipes showed many bands and variations among the different stocks on the gel. The stocks of F. velutipes in Japan were largely classified into three groups (tentatively named groups A, B, and C) according to the cluster analysis
of esterase isozymes. Some characteristics of the three groups were examined. Group C was characterized by a larger spore
size, slower spawn running, and a paler pileus color than groups A and B. Furthermore, group B showed a smaller spore size,
slower spawn running, and paler pileus color than group A.
Received: August 27, 2002 / Accepted: October 10, 2002
Correspondence to:K. Nishizawa 相似文献
144.
The Senescence-accelerated Mouse (SAM): A Higher Oxidative Stress and Age-dependent Degenerative Diseases Model 总被引:1,自引:0,他引:1
Chiba Y Shimada A Kumagai N Yoshikawa K Ishii S Furukawa A Takei S Sakura M Kawamura N Hosokawa M 《Neurochemical research》2009,34(4):679-687
The SAM strain of mice is actually a group of related inbred strains consisting of a series of SAMP (accelerated senescence-prone)
and SAMR (accelerated senescence-resistant) strains. Compared with the SAMR strains, the SAMP strains show a more accelerated
senescence process, a shorter lifespan, and an earlier onset and more rapid progress of age-associated pathological phenotypes
similar to human geriatric disorders. The higher oxidative stress status observed in SAMP mice is partly caused by mitochondrial
dysfunction, and may be a cause of this senescence acceleration and age-dependent alterations in cell structure and function.
Based on our recent observations, we discuss a possible mechanism for mitochondrial dysfunction resulting in the excessive
production of reactive oxygen species, and a role for the hyperoxidative stress status in neurodegeneration in SAMP mice.
These SAM strains can serve as a useful tool to understand the cellular mechanisms of age-dependent degeneration, and to develop
clinical interventions.
Special issue article in honor of Dr. Akitane Mori. 相似文献
145.
Reia Hosokawa Motonori Nagai Masaaki Morikawa Hidetoshi Okuyama 《World journal of microbiology & biotechnology》2009,25(9):1519-1528
Bioaugmentation for oil spills is a much more promising technique than is biostimulation. However, the effectiveness of bioaugmentation
is variable, because the survival and the xenobiotic-degrading ability of introduced microorganisms are highly dependent on
environmental conditions. As an alternative, autochthonous bioaugmentation (ABA) is proposed to overcome these difficulties.
The ABA method is like a ready-made bioaugmentation technology. In ABA, microorganisms indigenous to the contaminated site
or predicted contamination site that are well-characterized and potentially capable of degrading oils are used, and these
microorganisms should be enriched under conditions where bioaugmentation will be conducted. It is possible to obtain information
in advance on the chemical and physical characteristics of potential oil spill sites and of oils that might be spilled. The
application of ABA in the coastal areas of Hokkaido Prefecture, Japan, is considered here, because Hokkaido is located south
of Sakhalin Island, Russia, where development of oil fields is in progress. If oil spills in this region were well characterized
in advance, ABA could be a feasible technology in the near future. 相似文献
146.
Motoyuki Shimizu Tatsuya Fujii Shunsuke Masuo Kensaku Fujita Naoki Takaya Dr. 《Proteomics》2009,9(1):7-19
The fungus Aspergillus nidulans reduces nitrate to ammonium and simultaneously oxidizes ethanol to acetate to generate ATP under hypoxic conditions in a mechanism called ammonia fermentation (Takasaki, K. et al.. J. Biol. Chem. 2004, 279, 12414–12420). To elucidate the mechanism, the fungus was cultured under normoxic and hypoxic (ammonia fermenting) conditions, intracellular proteins were resolved by 2‐DE, and 332 protein spots were identified using MALDI MS after tryptic digestion. Alcohol and aldehyde dehydrogenases that play key roles in oxidizing ethanol were produced at the basal level under hypoxic conditions but were obviously provoked by ethanol under normoxic conditions. Enzymes involved in gluconeogenesis, as well as the tricarboxylic and glyoxylate cycles, were downregulated. These results indicate that the mechanism of fungal energy conservation is altered under hypoxic conditions. The results also showed that proteins in the pentose phosphate pathway as well as the metabolism of both nucleotide and thiamine were upregulated under hypoxic conditions. Levels of xanthine and hypoxanthine, deamination products of guanine and adenine were increased in DNA from hypoxic cells, indicating an association between hypoxia and intracellular DNA base damage. This study is the first proteomic comparison of the hypoxic responses of A. nidulans. 相似文献
147.
148.
149.
Ogawa E Hosokawa M Harada N Yamane S Hamasaki A Toyoda K Fujimoto S Fujita Y Fukuda K Tsukiyama K Yamada Y Seino Y Inagaki N 《Biochemical and biophysical research communications》2011,(1):115-120
Holocarboxylase synthetase (HLCS) catalyzes the covalent binding of biotin to both carboxylases in extranuclear structures and histones in cell nuclei, thereby mediating important roles in intermediary metabolism, gene regulation, and genome stability. HLCS has three putative translational start sites (methionine-1, -7, and -58), but lacks a strong nuclear localization sequence that would explain its participation in epigenetic events in the cell nucleus. Recent evidence suggests that small quantities of HLCS with a start site in methionine-58 (HLCS58) might be able to enter the nuclear compartment. We generated the following novel insights into HLCS biology. First, we generated a novel HLCS fusion protein vector to demonstrate that methionine-58 is a functional translation start site in human cells. Second, we used confocal microscopy and western blots to demonstrate that HLCS58 enters the cell nucleus in meaningful quantities, and that full-length HLCS localizes predominantly in the cytoplasm but may also enter the nucleus. Third, we produced recombinant HLCS58 to demonstrate its biological activity toward catalyzing the biotinylation of both carboxylases and histones. Collectively, these observations are consistent with roles of HLCS58 and full-length HLCS in nuclear events. We conclude this report by proposing a novel role for HLCS in epigenetic events, mediated by physical interactions between HLCS and other chromatin proteins as part of a larger multiprotein complex that mediates gene repression. 相似文献
150.
Takahashi A Kondoh M Uchida H Kakamu Y Hamakubo T Yagi K 《Biochemical and biophysical research communications》2011,(3):317-470
Passage across epithelial cell sheets is the first step in drug absorption. Tight junctions (TJs) are located between adjacent epithelial cells and seal the intercellular space preventing leakage of solutes. Claudin, a tetra-transmembrane protein family, is a pivotal functional and structural component of the TJ barrier. Modulation of the claudin-based TJ seal is a strategy for mucosal drug absorption. We previously found that a claudin-4 binder, a C-terminal fragment of Clostridium perfringens enterotoxin (C-CPE194), was a modulator of the TJ seal and a potent mucosal absorption enhancer. In the present study, we attempted to improve claudin-4 binders by modification of C-CPE194. Substitution of Asn at position 309 and Ser at position 313 with Ala increased the affinity to claudin-4 by 9.9-fold as compared to C-CPE194. Deletion of 10 amino acids in the N-terminal domain of the double-alanine-substituted mutant increased affinity to claudin-4 by 23.9-fold as compared to C-CPE194. These C-CPE194 mutants reversibly modulated the TJ seal in human intestinal epithelial cell sheets. The N-terminal-truncated mutant was the most potent modulator of the TJ seal. These findings indicate that the C-CPE mutant may be a promising lead for the development of a clinical TJ modulator. 相似文献