首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
  • 1.1. Three monoclonal antibodies have been produced which neutralize in vitro the haemolytic activity present in tentacle extracts of the box jellyfish (Chironex fleckeri).
  • 2.2. Two of these monoclonal antibodies bound specifically to a component of relative molecular mass 50,000 in tentacle extract on Western blots.
  • 3.3. This binding only occurred when the extracts were electrophoresed under non-reducing conditions.
  • 4.4. The third monoclonal antibody did not display binding to Western blots of tentacle extract under any of our experimental conditions.
  相似文献   

2.
  • 1.1. Babesia hylomysci has an aminopeptidase and an acid endoprotease
  • 2.2. The amino-peptidase has properties very similar to the aminopeptidase in Plasmodium yoelii nigeriensis and P. chabaudi.
  • 3.3. The acid endoprotease is specific towards haemoglobin and practically has no action on bovine serum albumin.
  • 4.4. In mouse normal red blood cells we find an acid protease having physico-chemical properties similar to the enzyme present in B. hylomysci extracts.
  • 5.5. The similarity of electrophoretic velocity between acid protease in B. hylomysci and non-infected red blood cells leads us to think that the acid protease of parasitic extracts comes from the host-cell.
  • 6.6. The proteolytic system of Babesia and Plasmodium are similar.
  相似文献   

3.
  • 1.1. Seed extracts of 20 plants species belonging to the family Cucurbitaceae were examined for their ability to inhibit protein synthesis in rabbit reticulocyte lysate and induce mid-term abortion in mice.
  • 2.2. Eleven extracts were found to inhibit protein synthesis by about or over 90%, seven extracts produced about 80% inhibition, one caused about 70% inhibition and one brought about approx. 40% inhibition, when the extracts were tested at a final concentration of 10 μg per ml.
  • 3.3. All of the seed extracts possessed potent mid-term abortifacient activity.
  • 4.4. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the seed extracts disclosed the existence of a Coomassie Blue-stainable band with a mol. wt of ca 30,000 Da. This band probably accounts for the protein synthesis inhibiting and mid-term abortifacient activities.
  • 5.5. There was a similarity in the electrophoretograms of seed extracts of plants belonging to the same genus.
  相似文献   

4.
  • 1.1. Creatine kinase (CPK) isozymes of extracts from the electric organ, dorsal muscle and brain of Electrophorus electricus (L.) were analysed with Cellogel electrophoresis. A single component corresponding to the MB-form was obtained for both electric organ and the dorsal muscle. The BB-form was present in the brain extract.
  • 2.2. Upon acetone fractionation of the aqueous extract of electric organ, the final fraction was submitted to gel filtration and presented a single peak of CPK activity.
  • 3.3. Characterization of this fraction by thin-layer gel filtration indicated an apparent molecular weight of 80,000 which corresponds to the enzyme dimeric structure.
  • 4.4. The implications of this finding with the muscular origin of the electric organ are discussed.
  相似文献   

5.
  • 1.1. The digestion proteases in five marine species (Atlantic halibut, Hippoglossus hippoglossus (L); Dover sole, Solea solea (L); turbot, Scophthalmus maximus, (L); European lobster, Hommarus gammaarus (L); and the giant prawn, Penaeus monodon) have been compared by biochemical methods.
  • 2.2. The pH profiles for the hydrolysis of casein by extracts from the digestive systems of each species showed different characteristics; extracts from adult halibut, turbot and sole exhibited strong pepsin-like activity; whereas this enzyme was absent in P. monodon and in sole larvae.
  • 3.3. Although lobster extracts, from either the hepatopancreas or the stomach, showed peaks at pH values of 5.8 and 2.5, this latter activity did not hydrolyse a specific substrate for pepsin.
  • 4.4. Halibut and turbot digestive extracts contained an activity optimal at pH values in the region of 5.0 resembling a cathepsin-like enzyme; an activity which was not evident in the other species under similar experimental conditions.
  • 5.5. Although all species possessed trypsin-like activity, the pH profiles of activity in the neutral to alkaline region were unique to each species.
  • 6.6. The significance of these results is considered with respect to the anatomical differences in the alimentary systems of these species.
  相似文献   

6.
  • 1.1. An alkaline p-nitrophenylphosphate phosphatase has been purified 440-fold from extracts of Hatobacterium halobium.
  • 2.2. The enzyme has an apparent molecular weight of 24,000.
  • 3.3. A Km value for p-nitrophenylphosphate of 1.12mM has been found under optimal conditions.
  • 4.4. The enzyme is selectively activated and stabilized by Mn2+.
  • 5.5. It requires high salt concentrations for stability and maximum activity.
  • 6.6. It displays an unusual restricted substrate specificity of 25 phosphate esters tested, only phosphotyrosine and casein were hydrolysed besides p-nitrophenylphosphate.
  相似文献   

7.
  • 1.1.|Intraspecific variation in the thermal physiology of Rana sylvatica was examined.
  • 2.2.|Heat and cold tolerances of both adult and larval representatives were determined for animals representing populations from New York, Maryland, Kentucky, Ohio, Michigan and Canada.
  • 3.3.|In general, frogs from more northern localities exhibited lower heat tolerances.
  • 4.4.|There was no evidence of interpopulational differences in cold tolerance. Similar trends were revealed by larval testing.
  • 5.5.|Interpopulational differences among laboratory-reared tadpoles suggests a strong genetic component to Rana sylvatica thermal physiology.
  相似文献   

8.
  • 1.1. Twenty organohalogen compounds, primarily phenols, were detected in the volatile extracts of the acorn worm Ptychodera bahamensis.
  • 2.2. Five chlorinated compounds, previously undescribed from acorn worms, were identified.
  • 3.3. Enteropneusts can be significant contributors of halogenated organics to the marine environment.
  相似文献   

9.
  • 1.1. The presence of VIP was investigated in the dogfish, Scyliorhinus canicula, the ballanwrasse. Lubrus berggylta and the bib. Trisopterus luscus, using a specific radioreceptorassay.
  • 2.2. Pure porcine VIP and gut extracts of fishes yielded similar dilution curves.
  • 3.3. In the dogfish, the highest concentration of VIP was found in the hindgut. In contrast, in the two teleostei studied, the highest levels of VIP were in the first part of the gut.
  • 4.4. The biologically active VIP measured by radioreceptorassay correlated well with the molecule determined using a specific radioimmunoassay.
  • 5.5. Our results support the hypothesis of the appearance of VIP early in evolution.
  相似文献   

10.
  • 1.1. A variety of haematological parameters were determined in adult Dasyurus viverrinus.
  • 2.2. Haemoglobin and red cell counts were high with a very low mean cell volume.
  • 3.3. Basophils are absent but the eosinophils contain small numbers of basophilic granules which may indicate a dual role for this cell.
  • 4.4. “Ring Form” leucocytes are present.
  • 5.5. Three types of red cell picture could be identified, some animals showing large numbers of spherocytes, spicule cells, and inclusion bodies.
  • 6.6. These cells resemble those found in some inherited human haemolytic anaemias but there was no evidence of haemolysis in the animals.
  • 7.7. An alkali resistant haemoglobin component is present.
  相似文献   

11.
  • 1.1. Microtubule reassembly was studied in brain extracts from pigs and rats deficient in zinc and from zinc-supplemented controls. Tubulin in extracts from zinc-deficient animals showed an impaired ability to repolymerize compared with extracts from control animals.
  • 2.2. Crude microtubule protein isolated from zinc-deficient rat brain contained less free SH groups than that isolated from zinc-supplemented animals.
  • 3.3. It is concluded that variation in zinc concentration close to the physiological range can influence microtubule assembly, and that zinc may have some function in microtubule polymerization in vivo.
  相似文献   

12.
  • 1.1. Tubulin has been isolated from brain of carp (Cyprinus carpio), acclimated to summer temperatures (16–20°C), and its in vitro reassembly behavior has been characterized.
  • 2.2. Among the striking properties of this tubulin preparation is the temperature profile showing a high level of polymerization at the environmental temperature of carp.
  • 3.3. The critical tubulin concentration for assembly was 0.8 mg/ml, which was higher than mammalian tubulin purified by the cycle procedure.
  • 4.4. The microtubular protein showed three high mol.wt component and a minor component of about 43,000 daltons was also found to copurify with tubulin.
  相似文献   

13.
  • 1.1. Inorganic phosphate (Pi) was absorbed rapidly by suspension-cultured cells of Catharanthus roseus which had previously been cultured in Pi-free Murashige Skoog medium.
  • 2.2. The intracellular levels of ATP, ADP and 5-phosphoribosyl-l-pyrophosphate (PRPP) increased markedly during the 24 hr which followed the addition of Pi (1.25mM).
  • 3.3. Availability of PRPP in vivo, estimated by the measurement of nucleotide synthesis from [8-14C]adenine, was also increased by addition of Pi.
  • 4.4. Only a 20% increase in the maximum catalytic activity of PRPP synthetase was observed in extracts of cells, prepared 24 hr after addition of Pi.
  • 5.5. In contrast to results for mammalian PRPP synthetase, the activity of PRPP synthetase, partially purified from Catharanthus roseus, was inhibited by concentration of Pi greater than 5mM.
  • 6.6. The mechanisms involved in the increased availability of PRPP and the synthesis of adenine nucleotides in the plant cells cultured in Pi-containing medium are discussed.
  相似文献   

14.
  • 1.1. Fifteen populations of 10 horse breeds ranging from 110 to 2232 individuals yielded 61 phenotypes of electrophoretic variants at six blood loci.
  • 2.2. The numbers of different hemotypes varied from 79 to 239, and the ratios of number of individuals to number of hemotypes varied from 1.38 to 9.34.
  • 3.3. The genetic structure of the pooled mixed breed population comprising 11,393 individuals disclosed features similar to those of the least diversified component breeds.
  • 4.4. The mean ratio of n individuals to n hemotypes was 11.33.
  • 5.5. This figure represents a first direct attempt to estimate the individual genetic diversity in horses.
  相似文献   

15.
  • 1.1. Extracts of roots, seeds and fruits of seventeen plant species belonging to Family Cucurbitaceae were examined for the ability to inhibit protein synthesis in rabbit reticulocyte lysate and induce mid-term abortion in mice.
  • 2.2. Out of the 22 tissue extracts examined, 16 were found to inhibit protein synthesis by >90%, three caused 65–85% inhibition and 3 caused <25% inhibition.
  • 3.3. In general, there was a close correlation between protein synthesis inhibiting activity and mid-term abortifacient activity of the tissue extracts.
  • 4.4. SDS-PAGE of the tissue extracts revealed the presence of a Coomassie Blue-stainable band with a mol. wt of ca 30,000. The data suggest that this band is responsible for the protein synthesis inhibiting and mid-term abortifacient activities.
  相似文献   

16.
  • 1.1. Halobacterium halobium has two chromatographically distinct forms of glutamate dehydrogenase which differ in their thermolability and other properties. One glutamate dehydrogenase utilizes NAD, the other NADP as a coenzyme.
  • 2.2. The NADP-specific glutamate dehydrogenase (EC 1.4.1.4) was purified 65-fold from crude extracts of H. halobium.
  • 3.3. The Michaelis constants for 2-oxoglutarate (13.3 mM), ammonium (3.1 mM) and NADPH (0.077 mM) indicate that the enzyme catalyzes in vivo the formation of glutamate from ammonium and 2-oxoglutarate.
  • 4.4. The amination of 2-oxoglutarate by NADP-specific glutamate dehydrogenase is optimal at the pH value of 8.0–8.5. The optimal NaCl or KCl concentration for the reaction is 1.6 M.
  • 5.5. None of the several metabolites tested for a possible role in the regulation of glutamate dehydrogenase activity appeared to exert an appreciable influence on the enzyme.
  • 6.6. NAD- and NADP-dependent glutamate dehydrogenases from H. halobium showed apparent molecular weights of 148,000 and 215,000 respectively.
  相似文献   

17.
  • 1.1. An apparent effect of insulin administration on enlargement of interscapular brown adipose tissue (BAT) was found in heat-exposed rats, but not in warm-adapted or cold-acclimated rats.
  • 2.2. BAT extracts from the heat-acclimated/insulin-treated (HI) rats notably increased the capillary growth in an in vitro angiogenesis model in which microvascular fragments and myofibroblastic (Mf) cells isolated from lipid tissues were grown in co-culture, although a direct effect of insulin was not high.
  • 3.3. BAT extracts from the HI rats stimulated the production of endothelial cell growth factor and collagen by Mf cells.
  • 4.4. It is probable that an increased angiogenic activity contributes to the capillary growth and tissue growth in BAT of HI rats.
  相似文献   

18.
  • 1.1. Native oxyhemoglobin components were isolated chromatographically from Paramecium caudatum and Paramecium primaurelia, and some properties of the isolated components were investigated.
  • 2.2. P. caudatum was endowed with one homogeneous hemoglobin component, while the hemoglobin in P. primaurelia was resolved into three heterogeneous components being two main and one minor.
  • 3.3. Spectral properties of the isolated hemoglobin components were quite similar to each other. The isolated components, however, were distinctly different in electrophoretic mobilities.
  • 4.4. Molecular weight of the isolated hemoglobin components was estimated to be about 11,000.
  相似文献   

19.
  • 1.1. Changes in the hemoglobins present in many vertebrates have been observed during development and during anemic episodes.
  • 2.2. A change in the number of hemoglobins present and their relative amounts was observed when adult Triturus cristalus newts were made anemic by injection of acetylphenylhydrazine.
  • 3.3. Hemoglobin IV, which is a minor hemoglobin in healthy adults, was found to be a major component during the subsequent erythropoietic response to hemolytic anemia.
  • 4.4. No new hemoglobin not already present in the non-anemic state was detected during the response to induced anemia.
  相似文献   

20.
  • 1.1. Spore coat extracts from Bacillus thuringiensis subspecies kurstaki and israelensis and Bacillus cereus T and B. cereus NRRL 569 were characterized by polyacrylamide gel electrophoresis in sodium dodecyl sulfate and by amino acid analysis.
  • 2.2. Both B. cereus spore coats had similar electrophoretic profiles.
  • 3.3. The B. thuringiensis spore coats contained crystal proteins as major components as well as lower mol. wt proteins.
  • 4.4. B. thuringiensis subsp. israelensis had a unique coat protein profile which was different from B. cereus and B. thuringiensis subsp. kurstaki coats.
  • 5.5. Insecticidal activity of spores against the tobacco hornworm, Manduca sexta, and the mosquito, Aedes aegypti, also was determined.
  • 6.6. B. thuringiensis subsp. kurstaki spores were lethally toxic to the tobacco hornworm (Lepidoptera) larvae, whereas spores of the other subspecies were not.
  • 7.7. Except for subspecies israelensis, none of the spores was effective against the mosquito (Diptera) larvae.
  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号