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91.
Takayoshi Yamagishi Kayo Sugitani Kiyoo Tanishima Shinichi Nakamura 《Microbiology and immunology》1997,41(4):295-299
In order to avoid the use of experimental animals, the polymerase chain reaction (PCR) method was applied to differentiate Clostridium perfringens into five toxin types. Twenty-two out of 23 strains tested produced the toxin(s) corresponding to the toxin gene(s) identified by PCR, and vice versa. Consequently, the gene typing was consistent with conventional typing by animal tests. Twenty-five strains were identified as types different from original ones by the PCR method as well as a toxin neutralization test. These findings suggest that the PCR method, which is easy and timesaving, is applicable to identify the toxin types of C. perfringens as an alternative to animal tests, and that beta-, epsilon- and iota-toxin genes might be lost by long-term preservation. The reasons why the strains lost the genes are discussed. 相似文献
92.
Two new glycerol glucosides, liliosides D and E, have been isolated from the leaves and stems of Lilium japonicum. Their structures have been elucidated by chemical, spectroscopic and synthetic methods. 相似文献
93.
Kayo H Yamazaki H Nishida H Dang NH Morimoto C 《Biochemical and biophysical research communications》2007,364(4):808-814
The cancer stem cell theory suggests that chemoresistance and recurrence of tumors are often due to the similarity of stem cell properties between normal and cancer cells. Adult T-cell leukemia/lymphoma (ATLL) has poor prognosis, suggesting that ATLL cells possess common stem cell properties. We analyzed side population (SP), a characteristic stem cell phenotype, and CD markers in ATLL cell lines. We found that several lines contained SP with expressions of some hematopoietic stem cell markers. On the other hand, treatment with interferon (IFN)-α is sometimes effective in ATLL, particularly combined with other drugs. We examined its effect on ATLL cells and found that IFN-α significantly reduced the SP proportion. Moreover, CD25-positive cells and phosphorylation of STAT1/5 and ERK were upregulated during this process. These data suggest that their stem cell properties render ATLL cells therapy-resistant, and IFN-α exerts its clinical effect through a reduction of the SP cell population. 相似文献
94.
A gene, blmA, from bleomycin (Bm)-producing Streptomyces verticillus, encodes a Bm-binding protein, designated BLMA. The expression of BLMA conferred resistance to Bm in the Escherichia coli host, whereas a mutant protein, designated Pro-9/Leu, with the N-terminal proline 9 residue in BLMA replaced by leucine, did not. We created a fusion protein between the maltose-binding protein (MBP) and a mutant protein Pro-9/Leu/Leu with Met-94 in Pro-9/Leu replaced by leucine. Pro-9/Leu/Leu from the fusion protein, obtained by digestion with CNBr digestion, did not inhibit DNA-cleaving and antibacterial activities of Bm. Native-polyacrylamide gel electrophoresis (PAGE) and gel filtration column chromatographic analysis showed that the molecular size of Pro-9/Leu/Leu is roughly half of that of BLMA, suggesting that the mutant protein cannot form dimeric structure. Furthermore, Far-UV circular dichroism (CD) spectrum of Pro-9/Leu/Leu was quite different from that of BLMA and similar to the spectra obtained from unordered proteins [Venyaminov, S.Y. and Vassilenko, K.S. (1994) Anal. Biochem. 222, 176–184], suggesting that the secondary structure of Pro-9/Leu/Leu is disrupted. These results indicate that the mutation abolishes not only dimer formation but also the secondary structure of BLMA, which results in the loss of its function as a Bm-resistance determinant. 相似文献
95.
Kayo Ikeda Koji Suzuki Hideki Yoshioka Katsushiro Miyamoto Tsutomu Masujima Masanori Sugiyama 《FEMS microbiology letters》1998,168(2):195-199
Streptomyces castaneoglobisporus HUT6202 overproduces a diffusible melanin pigment and harbors a cryptic 7.4-kb plasmid, pHY6202. We constructed a Streptomyces cloning vector, pSY10CMM, consisting of the HUT6202 rep gene, the thiostrepton resistance gene and an operon encoding the synthesis of melanin pigment, abbreviated mel, from S. castaneoglobisporus. The vector, which has SphI and BamHI sites as cloning sites with insertional inactivation of the mel, is a more convenient cloning vector than commonly used pIJ702, because of its broad host range for antibiotic-producing Streptomyces strains and its much greater production of diffusible melanin pigment. 相似文献
96.
Identification of heteromolecular binding sites in transcription factors Sp1 and TAF4 using high‐resolution nuclear magnetic resonance spectroscopy
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97.
98.
Goto M Ueda K Hashimoto T Fujiwara S Matsuyama K Kometani T Kanazawa K 《Free radical biology & medicine》2008,45(9):1318-1325
The oxidative formation of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in DNA is closely associated with the induction of degenerative diseases, including cancer. However, the oxidant species participating in the formation of 8-OHdG has yet to be fully clarified. On the basis that peroxyl radicals are a strong candidate for this species, we employed 2,2'-azobis(2-amidinopropane) (AAPH) as a peroxyl radical generator. Exposure of calf thymus DNA to AAPH formed 8-OHdG, but the exposure of 2'-deoxyguanosine (dG) alone did not. From the exposure of various combinations of nucleotides, 8-OHdG was formed only in the presence of dG and thymidine (dT). A mix of dG with an oxidation product of dT, 5-(hydroperoxymethyl)-2'-deoxyuridine, produced 8-OHdG, but the amount formed was small. In contrast, 8-OHdG was produced abundantly by the addition of dG to peroxidized dT with AAPH. Thus, the formation of 8-OHdG was mediated by the peroxidized dT. Instead of artificial AAPH, endogenous peroxyl radicals are known to be lipid peroxides, which are probably the oxidant species for 8-OHdG formation mediated by thymidine in vivo. 相似文献
99.
Modelling and predicting the potential habitat and future range expansion of invasive species can help managers to mitigate
the impact of such species. Because habitat suitability and the colonization process are key determinants of range expansion,
inferences drawn from invasion patterns should be based on both attributes. To predict the potential habitat and expansion
rate of the invasive tree Bischofia javanica on Hahajima Island, we used simultaneous models of habitat and dispersal to estimate the effect of environment and dispersal
from the source population on the current distribution. We compared the fit and the estimated magnitudes of the environment
and dispersal effects in the simultaneous models with those in habitat suitability and colonization kernel models. The values
of Akaike’s information criterion for the simultaneous models were better than those of the habitat suitability and colonization
kernel models, indicating that the current distribution of Bischofia was determined by both environment and dispersal. The simultaneous models predicted that the potential habitat of Bischofia would be larger than that predicted by the habitat suitability model. The potential habitat distribution and future invasion
predicted by the simultaneous models will contribute to the development of specific landscape-scale management plans to control
this invasive species. 相似文献
100.
Ken-ichi Morishita Nobumasa Yakushiji Fuminori Ohsawa Kayo Takamatsu Nobuyasu Matsuura Makoto Makishima Masatoshi Kawahata Kentaro Yamaguchi Akihiro Tai Kenji Sasaki Hiroki Kakuta 《Bioorganic & medicinal chemistry letters》2009,19(3):1001-1003
Retinoid X receptor (RXR) ligands are attractive candidates for clinical application because of their activity against tamoxifen-resistant breast cancer, taxol-resistant lung cancer, metabolic syndrome, and allergy. Though several RXR ligands, especially RXR antagonists, have been reported, the rational molecular design of such compounds is not well advanced. 4-[N-Methanesulfonyl-N-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-2-naphthyl)amino]nicotinic acid (5a) is a moderately RXRα-preferential agonist, and we examined the feasibility of replacing the methyl group on the sulfonamide with a longer alkyl chain or an aromatic ring as an approach to produce new RXR antagonists. Several of the resulting benzenesulfonanilide-type compounds showed RXR antagonist activity. This design strategy should be a useful approach for addressing the lack of structure diversity of RXR antagonists. 相似文献