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1.
Isolation and properties of extracellular proteinases from Sporothrix schenckii. 总被引:4,自引:0,他引:4 下载免费PDF全文
Sporothrix schenckii, mainly in the yeast form of the organism, produced extracellular proteinases when cultivated in liquid media containing albumin or collagen as a nitrogen source, but did not do so in brain heart infusion medium. Isolation of two extracellular proteinases from albumin-containing medium was performed by chromatography on DEAE-Sepharose CL-6B and Sephacryl S-200. Proteinase I had a molecular weight of 36,500, an optimal pH at 6.0, and a pI at 4.8. Despite its activities in weakly acidic conditions, proteinase I demonstrated chymotrypsinlike characteristics, these being indicated by strong inhibitory activity by phenylmethylsulfonyl fluoride and chymostatin and good kinetic constants for a synthetic chymotrypsin substrate, Suc-Ala-Ala-Pro-Phe-MCA. Proteinase II had a molecular weight of 39,000, an optimal pH at 3.5, and a pI at 3.8. Proteinase II showed cathepsin D-like characteristics, these being indicated by strong inhibitory activity by pepstatin, an acidic optimal pH, and good kinetic constants for hemoglobin. These two enzymes hydrolyzed natural substrates such as stratum corneum, type I collagen, and elastin although not type IV collagen. Proteinase production and cell growth in collagen-containing medium and the enzymatic digestion of skin constituents by isolated proteinases suggested that these two proteinases cooperatively enable the organism to invade skin and to obtain peptides from insoluble proteins. 相似文献
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An incomplete proviral genome of endogenous mammary tumour virus (MMTV) was found in DNA of several strains of mice. This MMTV-related sequence was assigned to the Y chromosome since it was clearly observed in male mice only. This MMTV provirus contained a sequence related to LTR (long terminal repeat), but not to gag-pol and env genes. NFS, NIH Swiss/S, STS/A, and DD/Tbr mice have this sequence but BALB/cHeA, SHN, SLN, C57BL/6NJcl, C3H/HeNJcl and CBA/JJcl mice are negative. In the strains containing this sequence, a DNA test for the sequence makes it possible to easily distinguish the DNAs of male or female mice. 相似文献
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Katayama Kazuhiro Hosui Atsushi Sakai Yoshiyuki Itou Minoru Matsuzaki Yasushi Takamori Yoriyuki Hosho Keiko Tsuru Tomomi Takikawa Yasuhiro Michitaka Kojiro Ogawa Eishin Miyoshi Yoko Ito Toshifumi Ida Shinobu Hamada Izumi Miyoshi Katsunori Kodama Hiroko Takehara Tetsuo 《Biological trace element research》2020,195(1):71-81
Biological Trace Element Research - The essential trace element zinc maintains liver functions. Liver diseases can alter overall zinc concentrations, and hypozincemia is associated with various... 相似文献
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Akiko Shibui Ayako Takamori Mohammed E.M. Tolba Aya Nambu Eri Shimura Sachiko Yamaguchi Chizu Sanjoba Hajime Suto Katsuko Sudo Ko Okumura Sumio Sugano Hideaki Morita Hirohisa Saito Kenji Matsumoto Susumu Nakae 《Biochemistry and Biophysics Reports》2016
IL-25, IL-33 and TSLP, which are produced predominantly by epithelial cells, can induce production of Th2-type cytokines such as IL-4, IL-5 and/or IL-13 by various types of cells, suggesting their involvement in induction of Th2-type cytokine-associated immune responses. It is known that Th2-type cytokines contribute to host defense against malaria parasite infection in mice. However, the roles of IL-25, IL-33 and TSLP in malaria parasite infection remain unclear. Thus, to elucidate this, we infected wild-type, IL-25?/?, IL-33?/? and TSLP receptor (TSLPR)?/? mice with Plasmodium berghei (P. berghei) ANKA, a murine malaria strain. The expression levels of IL-25, IL-33 and TSLP mRNA were changed in the brain, liver, lung and spleen of wild-type mice after infection, suggesting that these cytokines are involved in host defense against P. berghei ANKA. However, the incidence of parasitemia and survival in the mutant mice were comparable to in the wild-type mice. These findings indicate that IL-25, IL-33 and TSLP are not critical for host defense against P. berghei ANKA. 相似文献
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To investigate the genetic basis of cross-resistance to insecticides, natural populations of Drosophila melanogaster (Meigen) were first collected from four different locations in Japan. After 10-80 isofemale lines of each population had been established in a laboratory, the susceptibility of each line to each of the insecticides permethrin, malathion, fenitrothion, prothiophos, and DDT was examined. Broad ranges of continuous variation in susceptibility to all the chemicals were observed within each natural population as a whole. In addition, highly significant correlations among responses to organophosphates were observed. However, based on the coefficients of determination, about less than half of variation in responses to one insecticide could be explained by variation in responses to another insecticide, suggesting that not only a common resistance factor but also other factors could be involved in a natural population. Genetic analyses by using resistant and susceptible inbred lines from the same natural population demonstrated that resistance to organophosphates in some resistant lines could be due to a single or tightly linked factors, and that resistance in the other line may be due to more than one major factor. These observations could suggest that several resistance factors may be involved within each natural population, and that some of major factors could contribute to correlations among responses to organophosphates. These major factors could then contribute to the broad ranges of continuous variation observed at the level of the populations. 相似文献
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The present study was designed to investigate the antipsychotic-like effects of selective group II metabotropic glutamate receptor (mGluR) agonists, 5-[2-[4-(6-fluoro-1H-indole-3-yl) piperidin-1-yl]ethyl]-4-(4-fluorophenyl)thiazole-2-carboxylic acid amide (MGS0008) and (1R, 2S, 5S, 6S)-2-amino-6-fluoro-4-oxobicyclo[3.1.0]hexane-2,6-dicarboxylic acid monohydrate (MGS0028) on conditioned avoidance responses in rats. MGS0008 (1, 3 and 10 mg/kg, p.o.) and MGS0028 (0.3, 1 and 3 mg/kg, p.o.) significantly and reduced conditioned avoidance responses in a dose-dependent fashion. Similar effects were seen with LY418426 (0.3, 1 and 3 mg/kg, p.o.), but not with LY354740 (3, 10 and 30 mg/kg, p.o.), both of which are selective agonists for group II mGluR. Since this effect is seen with a wide range of antipsychotics, such as haloperidol and clozapine [Life Sciences 71 (2002) 947], group II mGluR agonists deserve further attention for possible antipsychotic activity. 相似文献
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Asaeda A Ide H Asagoshi K Matsuyama S Tano K Murakami A Takamori Y Kubo K 《Biochemistry》2000,39(8):1959-1965
The activity of human methylpurine DNA N-glycosylase (hMPG) for major substrates was directly compared using two types of substrates, i.e., natural DNA and synthetic oligonucleotides. By the use of ARP assay detecting abasic sites in DNA, we first investigated the activity on the natural DNA substrates containing methylpurines, ethenopurines, or hypoxanthine (Hx) prepared by the conventional methods. After the treatment with hMPG, the amount of AP sites in methylated DNA was much higher than that in DNA containing ethenopurines or Hx. The oligodeoxynucleotide having a single 7-methylguanine (7-mG) was newly synthesized in addition to 1, N(6)-ethenoadenine (epsilonA)-, Hx-, and 8-oxoguanine-containing oligonucleotides. 7-mG was effectively excised by hMPG, though it might be less toxic than the other methylated bases with respect to mutagenesis and cell killing. The kinetic study demonstrated that k(cat)/K(m) ratios of the enzyme for epsilonA, Hx, and 7-mG were 2.5 x 10(-3), 1.4 x 10(-3), and 4 x 10(-4) min(-1) nM(-1), respectively. The oligonucleotides containing epsilonA effectively competed against 7-mG, while Hx substrates showed unexpectedly low competition. Concerning the effect of the base opposite damage, hMPG much preferred Hx.T to other Hx pairs, and epsilonA.C and epsilonA.A pairs were better substrates than epsilonA.T. 相似文献