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931.
Degenerative muscle fiber accelerates adipogenesis of intramuscular cells via RhoA signaling pathway
Tohru Hosoyama Naomi IshiguroKeitaro Yamanouchi Masugi Nishihara 《Differentiation; research in biological diversity》2009
In some pathological conditions such as Duchenne muscular dystrophy, it has been known that a fatty infiltration in skeletal muscle is often observed and that is also one of primary factors to induce marked decline of muscular strength. However, the mechanism of fatty infiltration, cellular origin of accumulated adipocytes and its significance are not fully understood. The fact that persistent degenerative muscle fibers are present on dystrophic muscle leads us to hypothesize that muscle fiber condition affects fatty infiltration in skeletal muscle. We employed a single fiber culture system to determine whether fiber condition affects an appearance of adipocytes on the fibers. Artificially hyper-contracted muscle fibers (HCF), generated from isolated intact fibers (IF) of rat extensor digitrum longus muscle, were maintained as non-adherent cultures for 5–7 days. Interestingly, there appeared to be considerable numbers of mature adipocytes on HCF, whereas no adipocytes were seen on IF, indicating that cells on HCF spontaneously differentiated into mature adipocytes. Activation of RhoA signaling by the addition of thrombin decreased the number of adipocytes on HCF in a dose-dependent manner, whereas the number of MyoD-positive myoblasts increased. In contrast, Y-27632, a specific inhibitor of Rho kinases (ROCK), induced adipogenic differentiation of cells derived from IF. In addition, administration of Y-27632 into mouse regenerating muscle resulted in fat accumulation in the muscle. Taken together, the present studies clearly demonstrated that muscle fiber condition affects fat accumulation in skeletal muscle and that is possibly mediated by the RhoA signaling pathway. 相似文献
932.
Kazumasa Yasui Yasunobu Kano Kaori Tanaka Kunitomo Watanabe Mariko Shimizu-Kadota Hirofumi Yoshikawa Tohru Suzuki 《Nucleic acids research》2009,37(1):e3
We have developed a method to improve the transformation efficiency in genome-sequenced bacteria, using ‘Plasmid Artificial Modification’ (PAM), using the host''s own restriction system. In this method, a shuttle vector was pre-methylated in Escherichia coli cells, which carry all the putative genes encoding the DNA modification enzymes of the target microorganism, before electroporation was performed. In the case of Bifidobacterium adolescentis ATCC15703 and pKKT427 (3.9 kb E. coli-Bifidobacterium shuttle vector), introducing two Type II DNA methyltransferase genes lead to an enhancement in the transformation efficiency by five orders of magnitude. This concept was also applicable to a Type I restriction system. In the case of Lactococcus lactis IO-1, by using PAM with a putative Type I methyltransferase system, hsdMS1, the transformation efficiency was improved by a factor of seven over that without PAM. 相似文献
933.
Takashi Hattori Takashi Mine Nobukazu Komatsu Akira Yamada Kyogo Itoh Hitoshi Shiozaki Kiyotaka Okuno 《Cancer immunology, immunotherapy : CII》2009,58(11):1843-1852
To investigate the safety and immunological responses of personalized peptide vaccination in combination with oral administration
of UFT and UZEL for metastatic colorectal carcinoma (mCRC), fourteen patients were enrolled in the present study. Peptides
were determined based on the presence of peptide-specific cytotoxic T lymphocyte precursors and IgG in each patient. A maximum
of four peptides were subcutaneously administered weekly with UFT (300 mg/m2 day−1) and UZEL (75 mg/day) for 4 weeks, followed by 1 week of rest. This therapy was well-tolerated although there was a grade-3
skin reaction at the vaccination site in one patient. An increase in peptide-specific interferon-γ production or peptide-specific
IgG after the tenth vaccination was observed in nine of ten or eight of ten patients tested, respectively. IgG responses were
well correlated with overall survival (P = 0.0215). The safety and immunological responsiveness of the present therapy suggest that this combination would be of clinical
benefit for mCRC patients, and further trials are merited.
T. Hattori and T. Mine equally contributed to this work. 相似文献
934.
Takeshi Shimomura Tetsuji Itoh Touru Sumiya Fujio Mizukami Masatoshi Ono 《Enzyme and microbial technology》2009,45(6-7):443-448
Acetylcholine sensor is successfully prepared by using immobilized enzymes, i.e., acetylcholinesterase and choline oxidase within separate hybrid mesoporous silica membranes with 12 nm pore diameter (F127M). The measurement was based on the detection of hydrogen peroxide produced by two sequential enzyme reactions. The determination range and the response time are 6.0–800 μM and within approximately 3 min, respectively. The sensor is very stable compared to free enzymes and 80% of the initial response was maintained even after storage for 80 days. These results show that two enzymes are successfully immobilized and well stabilized, and at the same time, two sequential enzyme reactions efficiently proceed within the separate hybrid mesoporous membranes. Further, we studied the possible detection of organophosphorus pesticides in terms of the inhibition of acetylcholinesterase activity, i.e., the decrease of current response, and demonstrated that the nanomolar concentrations of pesticide (DZN-oxon) can be detected with our sensor. 相似文献
935.
Masaki Inoue Kazuhiro Ohtani Ryoji Kasai Mayu Okukubo Marta Andriantsiferana Kazuo Yamasaki Tohru Koike 《Phytochemistry》2009,70(9):1195-1202
Brine shrimp lethality assay-guided separation of the MeOH extract of leaves of Physena sessiliflora, which is endemic to Madagascar, afforded eight triterpene glycosides, Physenoside S1–4 and 16-β-[(d-xylopyranosyl)oxy]oxohexadecanyl homologues, Physenoside S5–8. Structural elucidation of these compounds was based on both spectroscopic analyses and chemical properties. Physenoside S7 and S8 have significant cytotoxic activities in the brine shrimp lethality assay. 相似文献
936.
Yuka Miyake Satoshi Tsuzuki Makoto Yasumoto Tohru Fushiki Kuniyo Inouye 《Cytotechnology》2009,60(1-3):95-103
Hepatocyte growth factor activator inhibitor type I (HAI-1) is a membrane-bound, serine protease inhibitor with two protease-inhibitory domains (Kunitz domain I and II). HAI-1 is known as a physiological inhibitor of a membrane-bound serine protease, matriptase. Paradoxically, however, HAI-1 has been found to be required for the extracellular appearance of the protease in an expression system using a monkey kidney COS-1 cell line. In the present study, we show using COS-1 cells that co-expression of recombinant variants of HAI-1 with the inhibition activity toward matriptase, including a variant consisting only of Kunitz domain I (the domain responsible for inhibition of matriptase), allowed for the appearance of this protease in the conditioned medium, whereas that of the variants without the activity did not. These findings suggest that the inhibition activity toward matriptase is critical for the extracellular appearance of protease in COS-1 cells. 相似文献
937.
Nobuhito Murai Yuka Miyake Satoshi Tsuzuki Kuniyo Inouye Tohru Fushiki 《Cytotechnology》2009,59(3):169-176
Matriptase is a type II transmembrane serine protease. This protease is strongly expressed in simple epithelial cells such
as enterocytes and kidney tubular cells in which the plasma membranes are separated into apical and basolateral domains. Although
matriptase was found previously to occur exclusively on the basolateral membrane of enterocytes, the underlying mechanism
of localization is unclear. In the present study, a full-length rat matriptase and a chimera consisting of the cytoplasmic
and transmembrane regions of the protease and green fluorescent protein (designated as 1–86GFP) were found to localize exclusively
to the basolateral membrane domain when expressed in Madin–Darby canine kidney epithelial cells. Mutagenesis analysis of 1–86GFP
revealed that the matriptase cytoplasmic juxtamembrane amino acid residues (Lys45, Val47, and Arg50) play a role in mediating
the localization in the cells. This study provides the first evidence that matriptase carries information for its localization
in simple epithelia. 相似文献
938.
The patch mosaic of an old-growth warm-temperate forest: patch-level descriptions of 40-year gap-forming processes and community structures 总被引:1,自引:0,他引:1
Tohru Manabe Kenichiro Shimatani Satoko Kawarasaki Shin-Ichi Aikawa Shin-Ichi Yamamoto 《Ecological Research》2009,24(3):575-586
Old-growth forests consist of various types of small patches that reflect their own gap-forming process, which includes changes
in environmental conditions occurring over several decades. We reconstructed the gap-forming processes that had occurred during
a 40-year period for eight representative patches of an old-growth evergreen broad-leaved forest in Japan, and examined the
current community structure. The selected patches were based on (1) changes in canopy heights estimated from aerial photographs
taken in four different years, (2) long-term ecological research (LTER) monitoring records, and (3) a recent field survey,
so that they sufficiently covered characteristic gap-forming processes such as a new gap, an old gap and consistently closed
canopy. Height and diameter at breast height (DBH) were measured on all living trees taller than 1.3 m. In their height distributions,
currently almost closed patches that were open in 1966 show a rotated sigmoid, whereas their DBH distributions are an inverse
J-shape. In contrast, patches that have been consistently under a closed canopy exhibit gentle inverse J-shapes for both distributions.
For species composition, there are no clear contrasts associated with the past gap-forming processes except for the existence
of fast-growing deciduous species in large currently open patches. Our results suggested that the variation in several decades
of gap-forming processes played a central role in the high patch diversity and the complex patch mosaic of the forest. Diverse
gap-forming processes created micro-environmental heterogeneity both vertically and horizontally, and contributed to the maintenance
of the species-rich, warm-temperate old-growth forest. 相似文献
939.
The spatial distribution of basidiocarps provides much information on the dispersal abilities, habitat preferences, and inter- and intraspecific interactions of aphyllophoraceous fungi. To reveal the spatial distribution and resource utilization patterns of aphyllophoraceous fungi in Malaysia, we conducted field observations in a primary forest in 2006 and analyzed the relationships between the abundance of eight dominant fungal species and various environmental factors. The topographical characteristics were significantly patchily distributed at the 100-m scale, whereas woody debris and most fungal species were distributed randomly. Although the dominant fungal species differed among the decay classes and diameters of the woody debris, the abundance of a few dominant species was significantly correlated with environmental factors. Although the latter factors might affect the spatial distribution of these fungi, the effects appear to be so small that they would not create an aggregated distribution at a few 100-m scales. 相似文献
940.