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131.
Molecular cloning, functional expression, and mutagenesis of cDNA encoding class I chitinase from rye (Secale cereale) seeds 总被引:2,自引:0,他引:2
Ohnuma T Taira T Yamagami T Aso Y Ishiguro M 《Bioscience, biotechnology, and biochemistry》2004,68(2):324-332
A cDNA encoding rye seed chitinase-a (RSC-a) was cloned by rapid amplification of cDNA ends and PCR procedures. It consists of 1,191 nucleotides and encodes an open reading frame of 321 amino acid residues. Recombinant RSC-a (rRSC-a) was produced in the oxidative cytoplasm of Escherichia coli Origami(DE3) in a soluble form by inducing bacteria at a low temperature (20 degrees C). Purified rRSC-a showed properties similar to the original enzyme from rye seeds in terms of chitinase activity toward a soluble substrate, glycolchitin, and an insoluble substrate, chitin beads, in chitin-binding ability to chitin, and in antifungal activity against Trichoderma sp. in vitro. rRSC-a mutants were subsequently produced and purified by the same procedures as those for rRSC-a. Mutation of Trp23 to Ala decreased the chitinase activity toward both substrates and impaired the chitin-binding ability. Furthermore, the antifungal activity of this mutant was weakened with increasing of the NaCl concentration in the culture medium. Complete abolishment of both activities was observed upon the mutation of Glu126 to Gln. The roles of these residues in both activities are discussed. 相似文献
132.
Expression profiles of fibrinolytic components in nasal mucosa 总被引:1,自引:1,他引:0
Sejima T Madoiwa S Mimuro J Sugo T Ishida T Ichimura K Sakata Y 《Histochemistry and cell biology》2004,122(1):61-73
133.
Kobayashi T Matsumoto T Ooishi K Kamata K 《American journal of physiology. Heart and circulatory physiology》2004,287(1):H135-H143
The aim of the present study was to compare vascular dysfunction between the early (12 wk old) and later (36 wk old) stages of spontaneous diabetes in Goto-Kakizaki (GK) rats. We also evaluated the aortic expression of the alpha(2D)-adrenoceptor and endothelial nitric oxide synthase (eNOS). Vascular reactivity was assessed in thoracic aortas from age-matched control rats and 12- and 36-wk GK rats. Using RT-PCR and immunoblots, we also examined the changes in expression of the alpha(2D-)adrenoceptor and eNOS. In aortas from GK rats (vs. those from age-matched control rats): 1) the relaxation response to ACh was enhanced at 12 wk but decreased at 36 wk; 2) the relaxation response to sodium nitroprusside was decreased at both 12 and 36 wk, 3) norepinephrine (NE)-induced contractility was decreased at 12 wk but not at 36 wk, 4) the expressions of alpha(1B)- and alpha(1D)-adrenoceptors were unaffected, whereas those of alpha(2D)-adrenoceptor and eNOS mRNAs were increased at both 12 and 36 wk; and 5) NE- and ACh-stimulated NO(x) (nitrite and nitrate) levels were increased at 12 wk, although at 36 wk ACh-stimulated NO(x) was lower, whereas NE-stimulated NO(x) showed no change. These results clearly demonstrate that enhanced ACh-induced relaxation and impaired NE-induced contraction, due to NO overproduction via eNOS and increased alpha(2D)-adrenoceptor expression, occur in early-stage GK rats and that the impaired ACh-induced relaxation in later-stage GK rats is due to reductions in both NO production and NO responsiveness (but not in eNOS expression). 相似文献
134.
In Japan Pseudopythina tsurumaru is an up to 10.8 mm-long commensal of the burrowing sea cucumber Protankyra bidentata, whereas in Hong Kong the same species is smaller and associated with the crab Hexapus anfractus, itself a commensal of P. bidentata. Japanese P. tsurumaru is a hermaphrodite tending towards protogyny maturing to a female when > or = 7 mm, and entering the hermaphroditic condition when > or = 9 mm long. In addition to normal euspermatozoa, the species produces 30-32 microm long and 7 x 8 microm broad spindle-shaped paraspermatozoa provided with a conical acrosome, a nucleus, and a bundle of approximately 15-16 flagella issuing from the head region. Paired pouch-formed seminal receptacles normally occur in bivalves > or = 6 mm. Bulk sperm transfer presumably takes place by way of spermatozeugmata formed by the two types of sperm cells. Exogenous euspermatozoa attach to particular nonepithelial cells that occupy the interior of the receptacles. These cells, together with their associated sperm, are probably released as syncytial sperm-carrying bodies into the suprabranchial chamber, where the ova are fertilized. 相似文献
135.
Endothelial progenitor cells for postnatal vasculogenesis 总被引:26,自引:0,他引:26
In the past decade, researchers have defined committed stem or progenitor cells from various tissues, including bone marrow, peripheral blood, brain, liver, and reproductive organs, in both adult animals and humans. Whereas most cells in adult organs are composed of differentiated cells, which express a variety of specific phenotypic genes adapted to each organ's environment, quiescent stem or progenitor cells are maintained locally or in the systemic circulation and are activated by environmental stimuli for physiological and pathological tissue regeneration. Recently, endothelial progenitor cells (EPCs) were isolated from peripheral blood CD34, Flk-1, or AC133 antigen-positive cells, which are considered to include a hematopoietic stem cell population, and were shown to be incorporated into foci of neovascularization. This finding, that circulating EPCs may home to sites of neovascularization and differentiate into endothelial cells in situ, is consistent with "vasculogenesis," a critical paradigm for embryonic neovascularization, and suggests that vasculogenesis and angiogenesis may constitute complementary mechanisms for postnatal neovascularization. Previous reports demonstrating therapeutic potential of EPC transplantation in animal models of hindlimb and myocardial ischemia opened the way to the clinical application of cell therapy: the replacement of diseased or degenerating cell populations, tissues, and organs. In this review, we summarize biological features of EPCs and speculate on the utility of EPCs for vascular and general medicine. cell transplantation; ischemia; neovascularization; stem cell 相似文献
136.
137.
Hypergravity caused by centrifugation inhibits elongation growth of shoots by decreasing the cell wall extensibility via suppression of xyloglucan breakdown as well as by the thickening of cell walls. The mechanism of graviperception in hypergravity-induced growth inhibition was investigated in Arabidopsis [A. thaliana (L.) Heynh.] hypocotyls and azuki bean (Vigna angularis Ohwi et Ohashi) epicotyls. Hypergravity caused growth suppression in both sgr1-1 and pgm1, which are Arabidopsis mutants deprived of gravitropism, as in wild-type plants, suggesting that the graviperception in hypergravity-induced growth inhibition of shoots is independent of that in gravitropism. Hypergravity had no effects on growth of azuki bean epicotyls or Arabidopsis hypocotyls in the presence of lanthanum or gadolinium, which are blockers of mechanoreceptors. Moreover, lanthanum or gadolinium at the same concentration had no influence on gravitropism of azuki bean epicotyls and Arabidopsis hypocotyls. Hypergravity had no effects on cell wall extensibility and affected neither xyloglucan metabolism nor the thickness of cell walls in the lanthanum- or gadolinium-treated azuki bean epicotyls. Lanthanum or gadolinium inhibited the hypergravity-induced increase in the pH of the apoplastic fluid in the epicotyls, which is involved in the processes of the suppression of xyloglucan breakdown due to hypergravity. These findings suggest that plants perceive the hypergravity stimuli by mechanoreceptors in the plasma membrane, and utilize the perceived signal to regulate the growth rate of their shoots.Abbreviations
HC-I
Hemicellulose-I
-
HC-II
Hemicellulose-II 相似文献
138.
139.
140.
Watanabe T Higuchi K Hamaguchi M Shiba M Tominaga K Fujiwara Y Matsumoto T Arakawa T 《American journal of physiology. Gastrointestinal and liver physiology》2004,287(4):G919-G928
TNF-alpha has numerous biological activities, including the induction of chemokine expression, and is involved in many gastric injuries. C-C chemokines [monocyte chemotactic protein (MCP)-1 and macrophage inflammatory protein (MIP)-1alpha] and C-X-C chemokines [MIP-2 and cytokine-induced neutrophil chemoattractant (CINC)-2alpha] mediate chemotaxis of monocytes and neutrophils, respectively. We examined the roles of TNF-alpha and dynamics of chemokine expression in gastric ulceration including ulcer recurrence and indomethacin-induced injury. Rats with healed chronic gastric ulcers received intraperitoneal TNF-alpha to induce ulcer recurrence. Some rats were given neutralizing antibodies against neutrophils or MCP-1 together with TNF-alpha. In a separate experiment, rats were orally administered 20 mg/kg indomethacin with or without pretreatment with pentoxifylline (an inhibitor of TNF-alpha synthesis) or anti-MCP-1 antibody. TNF-alpha (1 microg/kg) induced gastric ulcer recurrence after 48 h, which was completely prevented by anti-neutrophil antibody. TNF-alpha increased the number of macrophages and MCP-1 mRNA expression in scarred mucosa from 4 h, whereas it increased MPO activities (marker of neutrophil infiltration) and mRNA expression of MIP-2 and CINC-2alpha from 24 h. Anti-MCP-1 antibody inhibited leukocyte infiltration with reduction of the levels of C-X-C chemokines and prevented ulcer recurrence. Indomethacin treatment increased TNF-alpha/chemokine mRNA expression from 30 min and induced macroscopic erosions after 4 h. Pentoxifylline inhibited the indomethacin-induced gastric injury with reduction of neutrophil infiltration and expression of chemokine (MCP-1, MIP-2, and CINC-2alpha). Anti-MCP-1 antibody also inhibited the injury and these inflammatory responses but did not affect TNF-alpha mRNA expression. In conclusion, increased MCP-1 triggered by TNF-alpha may play a key role in gastric ulceration by regulating leukocyte recruitment and chemokine expression. 相似文献