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501.
The electron paramagnetic resonance(EPR) signals of Fusarium lipoxygenase were measured at liquid nitrogen temperature in the presence or absence of substrate, linoleic acid. The spin-state exchange of heme iron in Fusarium lipoxygenase from a low to high spin-state by the addition of linoleic acid was observed. The addition of linoleic acid to the enzyme at pH 9.0 gave rise to the appearance of EPR lines at g=5.92 and 3.58, while at pH 12.0, lines at g=6.12 and 3.41 were newly appeared. At the same time, the resonance at g=4.31 was increased both at pH 9.0 and 12.0 in the presence of linoleic acid. 相似文献
502.
Castasterone, [(22R,23R,24S)-2α,3α,22,23-tetrahydroxy-24-methyl-5α-cholestan-6-one] and typhasterol (2-deoxycastasterone) have been identified in purified extracts from the shoots of Sitka spruce (Picea sitchensis) by GC/MS. 相似文献
503.
In frog retina there are special rod photoreceptor cells ('green rods') with physiological properties similar to those of typical vertebrate rods ('red rods'). A cDNA fragment encoding the putative green rod visual pigment was isolated from a retinal cDNA library of the bullfrog, Rana catesbeiana. Its deduced amino acid sequence has more than 65% identity with those of blue-sensitive cone pigments such as chicken blue and goldfish blue. Antisera raised against its C-terminal amino acid sequence recognized green rods. It is concluded that bullfrog green rods contain a visual pigment which is closely related to the blue-sensitive cone pigments of other non-mammalian vertebrates. 相似文献
504.
Hisatomi O Honkawa H Imanishi Y Satoh T Tokunaga F 《Biochemical and biophysical research communications》1999,255(2):216-220
Three kinds of cDNAs encoding the putative photoreceptor-specific guanylate cyclases (GCs), OlGC-R1, OlGC-R2, and OlGC-C, were isolated from a retinal cDNA library of the medaka, Oryzias latipes. The deduced amino acid sequences of OlGC-R1 and -C are closely related but slightly different from those of OlGC4 and OlGC5, respectively. In situ hybridization locates the mRNA of both OlGC-R1 and -R2 in rods, and OlGC-C mRNA is found in all four types of cone cells. It is likely that medaka rods and cones produce distinct GC subtypes and that two kinds of photoreceptor-specific GCs are coexpressed in rods. Also, hybridization signals are detected in the pineal organ, suggesting that OlGC-R1 and -C contribute also to phototransduction in pinealocytes. 相似文献
505.
Makoto Ishikawa Hiroshi Watanabe Yoshio Koike Osamu Hisatomi Fumio Tokunaga Akira Tonosaki MD 《Cell and tissue research》1989,256(2):227-232
Summary Lectin cytochemical analysis was undertaken to examine the distribution of glycoconjugates associated with the short and long photoreceptor cells in the lamprey retina. Concanavalin A bound preferentially to the outer segment region of the short cells. Wheat germ agglutinin bound weakly to both long and short cells. The outer segment regions of the long cells were stained intensely with peanut agglutinin. Pretreatment with neuraminidase to remove sialic acid resulted in decreased binding of wheat germ agglutinin throughout the retina and increased binding of peanut agglutinin to the outer segment region of the short cells and the region of myoid process of the long cells. These results suggest that there is a difference in the distribution of glycoconjugate residues between the long and short cells. A rod-like character of the short cell and a cone-like character of the long are tentatively discussed. Lectin-binding patterns in other retinal regions is also examined. 相似文献
506.
The effect of galanin on pancreatic hormone release was studied using isolated perifused rat pancreatic islets. In the presence of 100 mg/dl glucose, 10(-8) mol/L galanin significantly inhibited the basal somatostatin release compared with the perifusion without galanin, whereas there was no significant change in the basal insulin and glucagon release. However, under stimulation of 20 mmol/L arginine, 10(-8) mol/L galanin significantly enhanced glucagon release and suppressed insulin and somatostatin release. These effects disappeared immediately after cessation of galanin infusion. Additionally, 10(-8) mol/L galanin significantly enhanced the first and second phase of glucagon release stimulated by arginine, whereas arginine-stimulated insulin and somatostatin releases were significantly inhibited in both phases. In the cysteamine-treated rat islets, neither enhancement of glucagon release nor suppression of insulin release by galanin was reproducible. These findings indicate two possible explanations. First, it is suggested that the effects of galanin on insulin and glucagon release may be direct and reversed by non-specific effect of cycteamine. Secondly, it seems likely that galanin-enhanced glucagon release may be indirect and in part due to the concomitant somatostatin suppression. Galanin may have an important regulatory function on endocrine pancreas. 相似文献
507.
A Murakami H Konomi N Itokazu M Arima N Sakuragawa A Nakajima M Tanaka S Tajima T Hayashi J Kino 《Journal of biochemistry》1989,106(3):490-494
Production of an unusual collagenous protein was observed in culture of dermal fibroblasts from four patients with Marfan syndrome. The apparent molecular weight of the protein was about 185 kDa after reduction with 2-mercaptoethanol and 175 kDa after limited pepsin treatment. The 185 kDa protein was susceptible to the bacterial collagenase but resistant to the animal collagenase. Immunoprecipitation revealed the specific interaction of the pepsin-treated 175 kDa collagenous protein with monoclonal and polyclonal antibodies to human type IV collagen. From the patterns of CNBr peptide mapping the 185 kDa band was identified as alpha 1 (IV) chain. Type IV collagen in the skin is generally considered to be of non-fibroblastic origin. However, in "diseased" condition, dermal fibroblasts might produce type IV collagen. The clinical manifestation in relation to production of type IV collagen by cultured skin fibroblasts from Marfan patients is discussed. 相似文献
508.
Prostaglandin D2 (PGD2) is a major prostanoid produced mainly by mast cells in allergic diseases, including bronchial asthma. However, its role in the pathogenesis of asthma remains unclear. PGD2-induced vasodilatation and increased permeability are well-known classical effects that may facilitate transendothelial migration of inflammatory cells, such as eosinophils, mast cells, lymphocytes, and monocytes in allergic inflammation. These effects are initiated via a PGD2 receptor, D prostanoid receptor (DP), and are referred to as DP-mediated vasodilation-extravasation. Recently, novel functions of DP have been identified. Furthermore, a novel and different receptor of PGD2, CRTH2, has been discovered. To date, DP and CRTH2 have been shown to be major PGD(2)-related receptors that have pivotal roles in mediating allergic diseases by effects such as directly regulating the migration of inflammatory cells and controlling the production of cytokines and lipid mediators. Available evidence suggests that CRTH2 and DP may collaborate in allergic inflammation. This review focuses on the novel roles of DP and CRTH2 in the initiation and maintenance of allergy. 相似文献
509.
510.
A. Hoque S. M. Rahman S. Arima Y. Takagi 《In vitro cellular & developmental biology. Plant》2001,37(3):369-374
Summary Embryonal explants from water chestnut (Trapa japonica Flerov) seeds germinated with high efficiency following a 40-d cold treatment at 5°C on half-strength MS (Murashige and Skoog)
medium supplemented with 2.7 μM N6-benzyladenine (BA), 0.5 μM 1-naphthaleneacetic acid (NAA) and 0.5 μM gibberellic acid (GA3). Control and chill-treated (different durations) embryonal explants were cultured onto media which contained half-strength
MS medium supplemented with different concentrations and combinations of cytokinins [BA, thidiazuron (TDZ), kinetin, zeatin],
auxin (NAA) and GA3. A liquid half-strength MS medium with 1.1 μM BA and 0.5 μM NAA resulted in the best shoot proliferation of control or chill-treated explants, and the addition of 0.5 μM GA3 stimulated axillary shoot elongation. Germination and shoot proliferation were always greater for chill-treated explants
compared with control explants under the same culture conditions. Shoots produced in vitro rooted 100% of the time in a liquid half-strength MS medium with 1.1 μM BA, 0.5 μM NAA and 1.1 μM indole-3-butyric acid, and the regenerated plantlets were established successfully in a water chestnut paddy field. 相似文献