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101.
Miura K Kamimura M Aizawa T Kiuchi M Hayakawa Y Mizuguchi M Kawano K 《Peptides》2002,23(12):36933-2116
Paralytic peptide of Bombyx mori (BmPP) is one of the multifunctional ENF-peptides; the name of “ENF” is the consensus N-terminal amino acid sequence of the family peptides. We revealed that BmPP significantly possesses growth-blocking activity and plasmatocyte-spreading activity and that its activity profiles are different from those of another ENF-family peptide, namely, the growth-blocking peptide of Pseudaletia separata (PsGBP). We also determined the NMR structures of BmPP and PsGBP under the same conditions, which revealed the structural differences of the first and second β-turn regions between the two peptides. On the basis of our results, it can be considered that the tertiary structural difference in these peptides may cause their different profiles of growth-blocking activity. 相似文献
102.
Yanagita M Shimabukuro Y Nozaki T Yoshimura N Watanabe J Koide H Terakura M Saho T Takedachi M Jang MH Kiyono H Murakami S 《Biochemical and biophysical research communications》2002,297(2):329-334
To investigate the biological activity of epithelial cells in view of host defense, we analyzed the mRNA expression of inducible NOS (iNOS) as well as NO production by human gingival epithelial cells (HGEC) stimulated with IL-15. RT-PCR analysis revealed that HGEC expressed IL-15 receptor alpha-chain mRNA. In addition, stimulation with IL-15 enhanced iNOS expression by HGEC through an increase of both mRNA and protein levels. Moreover, IL-15 up-regulated the production of NO(2)(-)/NO(3)(-), a NO-derived stable end product, from HGEC. The enhanced NO production by IL-15 was inhibited by AMT, an iNOS-specific inhibitor. These results suggest that IL-15 is a potent regulator of iNOS expression by HGEC and involved in innate immunity in the mucosal epithelium. 相似文献
103.
Kawada M Usami I Ohba S Someno T Kim J Hayakawa Y Nose K Ishizuka M 《Biochemical and biophysical research communications》2002,298(1):178-183
Hygrolidin family antibiotics showed selective cytotoxicity against both cyclin E- and cyclin A-overexpressing cells. Among them, hygrolidin was the most potent and inhibited growth of solid tumor-derived cell lines such as DLD-1 human colon cancer cells efficiently more than that of hematopoietic tumor cells and normal fibroblasts. FACS analysis revealed that hygrolidin increased cells in G1 and S phases in DLD-1 cells. While hygrolidin decreased amounts of cyclin-dependent kinase (cdk) 4, cyclin D, and cyclin B, it increased cyclin E and p21 levels. Hygrolidin-induced p21 bound to and inhibit cyclin A-cdk2 complex more strongly than cyclin E-cdk2 complex. Furthermore, hygrolidin was found to increase p21 mRNA in DLD-1 cells, but not in normal fibroblasts. Thus, hygrolidin inhibited tumor cell growth through induction of p21. In respect to p21 induction, inhibition of vacuolar-type (H+)-ATPase by hygrolidin was suggested to be involved. 相似文献
104.
Cl(-) concentration dependence of photovoltage generation by halorhodopsin from Halobacterium salinarum 下载免费PDF全文
The photovoltage generation by halorhodopsin from Halobacterium salinarum (shR) was examined by adsorbing shR-containing membranes onto a thin polymer film. The photovoltage consisted of two major components: one with a sub-millisecond range time constant and the other with a millisecond range time constant with different amplitudes, as previously reported. These components exhibited different Cl(-) concentration dependencies (0.1-9 M). We found that the time constant for the fast component was relatively independent of the Cl(-) concentration, whereas the time constant for the slow component increased sigmoidally at higher Cl(-) concentrations. The fast and the slow processes were attributed to charge (Cl(-)) movements within the protein and related to Cl(-) ejection, respectively. The laser photolysis studies of shR-membrane suspensions revealed that they corresponded to the formation and the decay of the N intermediate. The photovoltage amplitude of the slow component exhibited a distorted bell-shaped Cl(-) concentration dependence, and the Cl(-) concentration dependence of its time constant suggested a weak and highly cooperative Cl(-)-binding site(s) on the cytoplasmic side (apparent K(D) of approximately 5 M and Hill coefficient > or =5). The Cl(-) concentration dependence of the photovoltage amplitude and the time constant for the slow process suggested a competition between spontaneous relaxation and ion translocation. The time constant for the relaxation was estimated to be >100 ms. 相似文献
105.
Noriyuki Hatae Kumiko Yamaoka Yukihiko Sugimoto Manabu Negishi Atsushi Ichikawa 《Biochemical and biophysical research communications》2002,290(1):162-168
We previously demonstrated that the mouse EP3beta receptor and its C-terminal tail-truncated receptor (abbreviated T-335) expressed in Chinese hamster ovary cells showed agonist-dependent and fully constitutive Gi activity in forskolin-stimulated cAMP accumulation, respectively. Here we examined the effect of the EP3beta receptor or T-335 receptor on adenylyl cyclase activity stimulated by the Gs-coupled EP2 subtype receptor in COS-7 cells. As a result, sulprostone, a selective EP3 agonist, dose dependently augmented butaprost-stimulated adenylyl cyclase activity in EP3beta receptor- or T-335 receptor-expressing COS-7 cells. However, such adenylyl cyclase augmentation was not attenuated by either pertussis toxin treatment or expression of the PH domain of rat betaARK1, which serves as a scavenger of Gbetagamma subunits, but was partially attenuated by treatment with either 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetra(acetoxymethyl)ester, an intracellular Ca(2+) chelator, or W-7, a calmodulin inhibitor. These findings suggest that the C-terminal tail of the EP3beta receptor is not essentially involved in activation of EP2 receptor-stimulated adenylyl cyclase in a Ca(2+)/calmodulin-dependent but Gbetagamma subunit-independent manner. 相似文献
106.
Ohyama K Yamano Y Sano T Nakagomi Y Wada M Inagami T 《Biochemical and biophysical research communications》2002,292(2):362-367
To delineate the functional importance of the highly conserved triplet amino acid sequence, Asp-Arg-Tyr (DRY) among G protein-coupled receptors in the second intracellular loop, these residues of rat angiotensin II (Ang II) receptor type 1A (AT(1A)) were changed by alanine or glycine by site-directed mutagenesis. These mutant receptors were stably expressed in CHO-K1 cells, and the binding of Ang II, GTP effect, InsP(3) production, and the acidification of the medium in response to Ang II were determined. The effects of GTPgammaS on Ang II binding in the mutant receptors D125A and D125G were markedly reduced. InsP(3) production of the mutant D125A, D125G, R126A, and R126G was markedly reduced. Extracellular acidification of D125A was not distinguishable from untransfected CHO-K1 cells. Mutant Y127A was able to produce InsP(3) and acidify medium comparable with wild type AT(1A). These results indicate as follows; Asp(125) is essential for intracellular signal transduction involving G protein coupling, Arg(126) is essential for coupling of G(q) protein but not other G proteins, and Tyr(127) is not important for G protein coupling. 相似文献
107.
Katakai T Hara T Sugai M Gonda H Nambu Y Matsuda E Agata Y Shimizu A 《The Journal of biological chemistry》2002,277(52):50948-50958
We analyzed differences in the transendothelial migration (TEM) ability of T-helper (Th)-1 and Th2 cells across a murine endothelial cell line (F-2) under static conditions. The TEM abilities of Th1 cells from mice bearing autoimmune diseases and antigen-specific Th1 cell lines were severalfold higher than those of Th2 cells and lines of the same origin. These preferences were observed without exogenous chemoattractant and were insensitive to pertussis toxin, which completely blocks TEM induced by exogenous chemoattractants. Antibodies against LFA-1 and ICAM-1 as well as CD44 markedly blocked the TEM of Th1 cells. TEM ability was also blocked by pharmacological inhibitors of Src family protein-tyrosine kinases (PP2 and herbimycin A), phosphatidylinositol 3-kinase (wortmannin), and phosphatidylinositol-specific phospholipase C (). Cross-linking of CD44 strongly induced highly elongated morphology in Th1 lines, but weakly in Th2 lines. The pharmacological inhibitors that blocked TEM also inhibited this morphological change, whereas pertussis toxin did not. These data indicate that there are signaling pathways for TEM independent of chemokine attraction, but through adhesion molecules including CD44, and that the preferential TEM ability of Th1 over Th2 cells is formed, at least in part, by intrinsic differences in these pathways. 相似文献
108.
Similarity of tetracycline resistance genes isolated from fish farm bacteria to those from clinical isolates 总被引:2,自引:0,他引:2
Furushita M Shiba T Maeda T Yahata M Kaneoka A Takahashi Y Torii K Hasegawa T Ohta M 《Applied and environmental microbiology》2003,69(9):5336-5342
Tetracycline-resistant (Tet(r)) bacteria were isolated from fishes collected at three different fish farms in the southern part of Japan in August and September 2000. Of the 66 Tet(r) gram-negative strains, 29 were identified as carrying tetB only. Four carried tetY, and another four carried tetD. Three strains carried tetC, two strains carried tetB and tetY, and one strain carried tetC and tetG. Sequence analyses indicated the identity in Tet(r) genes between the fish farm bacteria and clinical bacteria: 99.3 to 99.9% for tetB, 98.2 to 100% for tetC, 99.7 to 100% for tetD, 92.0 to 96.2% for tetG, and 97.1 to 100% for tetY. Eleven of the Tet(r) strains transferred Tet(r) genes by conjugation to Escherichia coli HB-101. All transconjugants were resistant to tetracycline, oxycycline, doxycycline, and minocycline. The donors included strains of Photobacterium, Vibrio, Pseudomonas, Alteromonas, Citrobacter, and Salmonella spp., and they transferred tetB, tetY, or tetD to the recipients. Because NaCl enhanced their growth, these Tet(r) strains, except for the Pseudomonas, Citrobacter, and Salmonella strains, were recognized as marine bacteria. Our results suggest that tet genes from fish farm bacteria have the same origins as those from clinical strains. 相似文献
109.
Satani M Takahashi K Sakamoto H Harada S Kaida Y Noguchi M 《Protein expression and purification》2003,28(2):293-302
We report the purification and characterization of human bifunctional peptidylglycine alpha-amidating monooxygenase (the bifunctional PAM) expressed in Chinese hamster ovary cells. PAM is in charge of the formation of the C-terminal amides of biologically active peptides. The bifunctional PAM possesses two catalytic domains in a single polypeptide, peptidylglycine alpha-hydroxylating monooxygenase (PHM, EC 1.14.17.3) and peptidylamidoglycolate lyase (PAL, EC 4.3.2.5). By introducing a stop codon at 835 Glu, we were able to eliminate the membrane-spanning domain in the C-terminal region and succeeded in purifying a soluble form of bifunctional PAM that was secreted into the medium. Through a three-step purification procedure, we obtained 0.3mg of the purified PAM, which showed a single band at 91 kDa on SDS-PAGE, from 1L of monolayer culture medium. Metals contained in the purified PAM were analyzed and chemical modifications were performed to gain insight into the mechanism of the PAL reaction. Inductively coupled plasma detected 0.62 mol of Zn(2+) and 1.25 mol of Cu(2+) per mol of bifunctional PAM. Further, the addition of 1mM EDTA reduced the PAL activity by about 50%, but the decreased activity was recovered by the addition of an excess amount of Zn(2+). In a series of chemical modifications, phenylglyoxal almost completely eliminated the PAL activity and diethyl pyrocarbonate suppressed activity by more than 70%. These findings implied that Arg and His residues might play crucial roles during catalysis. 相似文献
110.
Yoshida M 《Zoological science》2003,20(12):1499-1500