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141.
Fluorescent microscopy was proved to be effective for structural identification of permineralized plant tissues in calcite
nodules from the Upper Cretaceous of Hokkaido, Japan. A minute, scale-like projection on the bract of a fossil Taxodiaceous
cone is identified as a true ovuliferous scale because it is bordered with a continuous epidermis that exhibits prominent
fluorescence. The presence of the ovuliferous scale suggests that the fossil is aTaiwania archetype. 相似文献
142.
143.
Takeshi Shimizu Hiroaki Kinoh Masaaki Yamaguchi Norio Suzuki 《Development, growth & differentiation》1990,32(5):473-487
A sialoglycoprotein and a fucose sulfate glycoconjugate (FSG) were purified from egg jelly of the sea urchin Hemicentrotus pulcherrimus . Sialoglycoprotein which consisted of sialic acid (90%, w/w) and protein (10%, w/w) did not cause induction of the acrosome reaction and sperm isoagglutination. FSG which contained one mol sulfate/mol fucose possessed 2.0 times protein to fucose by weight. The proteins in intact FSG were separated to two major (258 kDa and 237 kDa) and one minor (120 kDa) proteins by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) in the presence of 2-mercaptoethanol (2-ME) while the proteins could not be separated by HPLC in the presence of 0.1% SDS or SDS-PAGE without 2-ME. However, after carboxymethylation of FSG, two major (260 kDa and 240 kDa) proteins and two minor (140 kDa and 135 kDa) proteins were separated from the fucose sulfate moiety by HPLC in the presence of 0.1% SDS or SDS-PAGE without 2-ME. When FSG was first carboxymethylated with non-radioactive iodoacetic acid and then reduced with 2-ME and finally carboxymethylated with 14 C-iodoacetic acid, the most of radioactivity was detected in 140 kDa and 135 kDa proteins. Carboxymethylted-FSG was less potent than intact FSG in induction of the acrosome reaction. Fucoidan, a fucose sulfate polymer, did not induce the acrosome reaction. 相似文献
144.
Cytosolic and mitochondrial isoenzymes of branched-chain amino acid aminotransferase during development of the rat. 总被引:3,自引:3,他引:0 下载免费PDF全文
The isoenzymic forms of branched-chain amino acid aminotransferase in mitochondria of rat tissues were compared with the better-known cytosolic forms in order to find any regular pattern of expression of these isoenzymes during development. Mitochondria of all tissues examined except brain contained only a type-I isoenzyme differing from the cytosolic type-I isoenzyme in heat stability and activation by mercaptoethanol. Foetal and adult brain mitochondria contained isoenzymes type III as well as type I. The large excess of type-I isoenzyme in foetal liver was localized in mitochondria, apparently of haematopoietic cells. The activity of this isoenzyme declined precipitously (by 80%) from day 19 of gestation at the same period and rate as does the volume fraction of haematopoietic cells that are then leaving the liver. Cortisol treatment accelerated the loss of these cells, and proportionally accelerated loss of the mitochondrial isoenzyme I. A development succession of type-I isoenzyme by the unique type II of liver parenchymal cell cytosols could not be demonstrated, since small, about equal, amounts of types I and II were always present in cytosols of foetal and adult liver. Developmental succession of isoenzymes within tissues was limited to cytosols and was demonstrated by the presence of cytosolic isoenzyme III in foetal and newborn skeletal muscle and kidney, organs which contain only isoenzyme I in the adult. 相似文献
145.
Michiru Tanaka Jiro Hasegawa Junzo Tsutsumi Takeshi Fujita 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1982,231(2):301-310
A highly specific and sensitive method for the determination of the anti-ulcer drug geranylgeranylacetone (GGA) in human serum is described. The extract from serum with hexane was saponified with potassium hydroxide and subjected to silica gel column chromatography to remove interfering substances. GGA in the partially purified extract was then reacted with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine and measured by selected ion monitoring using gas chromatography—mass spectrometry. A low detection limit (1 ng/ml) and high precision were obtained. 相似文献
146.
Hiroaki Matsui Takeshi Kato† Chosabro Yamamoto Keisuke Fujita ‡ Toshiharu Nagatsu† 《Journal of neurochemistry》1981,37(2):289-296
Abstract: This paper describes a new, sensitive assay for dopamine-β-hydroxylase (DBH) activity in human cerebrospinal fluid (CSF), serum and brain tissues by high performance liquid chromatography (HPLC) with electrochemical detection (ED). Dopamine (DA) was used as a substrate and was incubated under optimal conditions. Norepinephrine (NE) formed enzymatically from DA was isolated by a double-column procedure, the first column of Dowex-50-H+ and the second column of aluminum oxide. NE was adsorbed on the second aluminum oxide column and then eluted with 0.5 M-hydrochloric acid and assayed by HPLC-ED. Epinephrine (EN) was added to each incubation mixture as an internal standard, and this assay was therefore highly reproducible. The peak height in HPLC was linear from 500 fmol to 100 pmol of NE and EN. The lower limit of detection for NE formed enzymatically was about 30 pmol, which indicated that the sensitivity of this procedure was comparable to that of radioassay procedures. We applied the method to measurement of the activity of and examination of some of the characteristics of DBH in human CSF. DBH activity in CSF of Parkinsonian patients was lower than that of control patients. The properties of DBH in human CSF were similar to those in serum and adrenal medulla. 相似文献
147.
Construction of a physical map of a kanamycin (Km) transposon, Tn5, and a comparison to another km transposon, Tn903 总被引:6,自引:0,他引:6
Summary A cleavage map of Tn5, a kanamycin (Km) transposon from plasmid JR67, was constructed from pMKI, a composite plasmid of ColE1 and Tn5, and compared to that of Tn903, a Km transposon from plasmid R6-5. The two transposons showed marked heterogeneity in both the structural gene for Km resistance and the inverted repeat regions as evidenced by their distinctly different restriction maps. This result suggests separate paths of evolution for the two Km transposons. 相似文献
148.
Active oxygen participation in chlorophyll destruction and lipid peroxidation in SO2-fumigated leaves of spinach 总被引:22,自引:0,他引:22
Shimazaki Ken-ichiro; Sakaki Takeshi; Kondo Noriaki; Sugahara Kiyoshi 《Plant & cell physiology》1980,21(7):1193-1204
Chlorophyll a and carotenoids of spinach began to be destroyed2 to 3 hr after fumigation with 2 ppm SO2 under light, whereaschlorophyll b was undamaged during 8 hr of exposure to SO2.Pheophytin a was not affected by the fumigation. When disks excised from leaves fumigated with SO2 at 2 ppm for2 hr were illuminated, chlorophyll a and carotenoids were brokendown, while they were not destroyed in darkness. The destructionof these pigments was suppressed under nitrogen. Chlorophylla destruction was inhibited by l,2-dihydroxybenzene-3,5-disulfonate(tiron), hydro-quinone and ascorbate, but not by l,4-diazabicyclo-[2,2,2]-octane(DABCO), methio-nine, histidine, benzoate and formate. Chlorophylla destruction was inhibited by phenazine methosulfate but stimulatedby methyl viologen. Addition of superoxide dismutase (SOD) tothe homogenate of SO2-fumigated leaves inhibited the chlorophylla destruction. The activity of endogenous SOD was reduced to40% by 2-hr fumigation before the loss of chlorophyll was observed.These results suggest that chlorophyll a destruction by SO2was due to superoxide radicals (O2). Moreover, malondialdehyde (MDA), a product of lipid peroxidation,was formed in SO2-fumigated leaves. MDA formation was inhibitedby tiron, hydroquinone and DABCO but not by benzoate and formate.MDA formation was increased by D2O. These results suggest thatlipid peroxidation in SO2-fumigated leaves was due to singletoxygen 1O2 produced from O2. (Received May 15, 1980; ) 相似文献
149.
Active oxygen participation in chlorophyll destruction and lipid peroxidation in SO2-fumigated leaves of spinach 总被引:1,自引:0,他引:1
Shimazaki Ken-ichiro; Sakaki Takeshi; Kondo Noriaki; Sugahara Kiyoshi 《Plant & cell physiology》1980,21(8):1193-1204
Chlorophyll a and carotenoids of spinach began to be destroyed2 to 3 hr after fumigation with 2 ppm SO2 under light, whereaschlorophyll b was undamaged during 8 hr of exposure to SO2.Pheophytin a was not affected by the fumigation. When disks excised from leaves fumigated with SO2 at 2 ppm for2 hr were illuminated, chlorophyll a and carotenoids were brokendown, while they were not destroyed in darkness. The destructionof these pigments was suppressed under nitrogen. Chlorophylla destruction was inhibited by l,2-dihydroxybenzene-3,5-disulfonate(tiron), hydro-quinone and ascorbate, but not by l,4-diazabicyclo-[2,2,2]-octane(DABCO), methio-nine, histidine, benzoate and formate. Chlorophylla destruction was inhibited by phenazine methosulfate but stimulatedby methyl viologen. Addition of superoxide dismutase (SOD) tothe homogenate of SO2-fumigated leaves inhibited the chlorophylla destruction. The activity of endogenous SOD was reduced to40% by 2-hr fumigation before the loss of chlorophyll was observed.These results suggest that chlorophyll a destruction by SO2was due to superoxide radicals (O2). Moreover, malondialdehyde (MDA), a product of lipid peroxidation,was formed in SO2-fumigated leaves. MDA formation was inhibitedby tiron, hydroquinone and DABCO but not by benzoate and formate.MDA formation was increased by D2O. These results suggest thatlipid peroxidation in SO2-fumigated leaves was due to singletoxygen 1O2 produced from O2. (Received May 15, 1980; ) 相似文献
150.
Fusarium solani M-13-1 was shake-cultured in a medium containing guaiacylglycerol-β-coniferyl ether (I), a model compound representing the arylglycerol-β-aryl ether linkage in lignin, as sole carbon source. From the culture filtrate guaiacylglycerol-β-coniferyl aldehyde ether (II) and guaiacylglycerol-β-ferulic acid ether (III) were isolated as metabolic products. Incubation with (III) resulted in formation of guaiacylglycerol-β-vanillin ether (IV), which was further metabolized to guaiacyglycerol-β-vanillic acid ether (V). The results indicate that the cinnamyl alcohol group of (I) is initially oxidized to an aldehyde group, which is further oxidized to a carboxyl group, yielding (II) and (III). Compound (III) is converted to (IV) by the release of a C2 fragment, and the aldehyde group of (IV) is further oxidized to a carboxyl group, giving (V). In the pathway from (I) to (V), neither oxidation of the benzylic secondary alcohol to ketone nor cleavage of the arylglycerol-β-aryl ether linkage was observed. The fungus was found to attack both erythro and threo form without distinction. 相似文献