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. C-reactive protein (CRP) isolated from a marine teleost (Cyclopterus lumpus L.) an structurally resembling mammalian CRP was added to cultures of leucocytes obtained from fish peripheral blood or mouse spleens.
  • 2.2. A statistically significant dose-dependent stimulation by the fish CRP, of [3H]thymidine incorporation into normal mouse spleen cells, was observed. The effect was substantially reduced in the presence of phosphorylcholine.
  • 3.3. Addition of fish CRP to fish leucocytes or to cultures of nu nu mouse spleen cells did not result in significant stimulation. This suggests that although the CRP is not mitogenic for fish leucocytes it exerts a selective stimulatory effect on mouse T cells.
  • 4.4. A synergistic stimulatory effect between fish CRP and PHA was abolished by phosphorylcholine and suggests that phosphorylcholine residues may contribute to the binding sites of mammalian lymphocytes.
  相似文献   

2.
  • 1.1. A choriolytic enzyme was isolated from the hatching medium of the pike, Esox lucius.
  • 2.2. The enzyme is defined as hatching enzyme.
  • 3.3. The molecular weight of the enzyme is 24,000.
  • 4.4. The enzyme is a glycoprotein containing 2% carbohydrate.
  • 5.5. Its isoelectric point is 6.5.
  • 6.6. The pH optimum is around pH 8.
  • 7.7. The enzyme molecule contains two disulfide bonds but no free cysteine.
  • 8.8. Inhibitor studies and metal analysis show that the enzyme is a zinc-metalloprotease.
  相似文献   

3.
  • 1.1. Serum from the Pacific hagfish,Eptatretus stouti,contains a complement-like protein (CLP).
  • 2.2. CLP from unfractionated hagfish serum and from affinity-purified preparations binds to yeast cell surfaces.
  • 3.3. Incubation with CLP enhances the phagocytosis of yeast by hagfish leukocytes.
  • 4.4. CLP-mediated opsonization can be inhibited by anti-CLP antibody, EDTA, d(+)mannose and l(+)rhamnose.
  • 5.5. Additional opsomic factors are also in hagfish serum.
  相似文献   

4.
  • 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   

5.
  • 1.1. Procarboxypeptidase (W-PCPA) was purified from the pancreas of the sei whale Balaenoptera bolealis.
  • 2.2. W-PCPA was obtained as a homogeneous protein in polyacylamide gel disc electrophoresis.
  • 3.3. W-PCPA has a molecular weight of 75,000.
  • 4.4. Amino acid composition of W-PCPA was compared with that of bovine procarboxypeptidase as A S5 (PCPA-S5).
  • 5.5. W-PCPA may be two subunits, and the aggregate form may resemble PCPA-S5.
  相似文献   

6.
This paper comments on: Low, B. S., Alexander, R. D., and Noonan, K.M. Human hips, breast, and buttocks: Is fat deceptive? Ethology and Sociobiology 8: 249-247, 1987. In it I argue that:
  • 1.1. Sexual selection has probably not been the most important selection pressure on
  • 2.female human body shape.
  • 3.2. Male humans in different cultures find different aspects of the female body attractive
  • 4.and therefore are unlikely to have exerted consistent directional sexual selection on
  • 5.the female body.
  • 6.3. Breast size is not correlated with lactation success.
  • 7.4. Visible hip width is not correlated with parturition success.
  • 8.5. Women would lower their fitness if they tried to deceive men about their internal
  • 9.pelvic dimensions.
  • 10.6. There are many alternative hypothesis to explain the existence of fat onwomen's
  • 11.breast, hips, and buttocks.
  相似文献   

7.
  • 1.1. The hydrolysis of glycol chitin preparations by several β-N-acetylglucosaminidases was monitored colorimetrically with the potassium ferriferrocyanide reagent.
  • 2.2. Glycol chitin samples from crab and insect sources varied considerably in chemical composition and susceptibility to enzymatic hydrolysis.
  • 3.3. Insect endochitinase preferred crab glycol chitin as substrate while hen's egg white lysozyme preferred commercial glycol chitin.
  • 4.4. Insect glycol chitin was well hydrolyzed by both enzymes.
  • 5.5. Insect exochitinase did not digest glycol chitin.
  相似文献   

8.
  • 1.1. A purification procedure for a thioredoxin from the extremophilic archaeon Sulfolobus solfataricus is described.
  • 2.2. The thioredoxin is active in the dithiothreitol-dependent reduction of insulin disulfide bonds.
  • 3.3. The thioredoxin is a monomer of 24,800 Da; it is an acidic protein with a pi of 4.5.
  • 4.4. The protein is stable to heating for 3 hr at 90°C.
  • 5.5. The amino acid composition of S. solfataricus thioredoxin is reported.
  相似文献   

9.
Company news     
Including information on:
  • ScanSoft
  • SpeechWorks International
  • Viisage Technology
  • Firstec
  • BIO-key International
  • HP
  • ZN Vision Technologies
  • Unisys
  • US Government’s
  • Communication Intelligence Corporation
  • Infinity Technologies
  相似文献   

10.
  • 1.1. To characterize an enzyme which metabolizes retinal in liver microsomes, several properties of the enzymatic reaction from retinal to retinoic acid were investigated using rabbit liver microsomes.
  • 2.2. The maximum pH of the reaction in the liver microsomes was 7.6.
  • 3.3. The Km and Vmax values for all-trans, 9-cis and 13-cis-retinals were determined.
  • 4.4. The reaction proceeded in the presence of NADPH and molecular oxygen.
  • 5.5. The incorporation of one atom of molecular oxygen into retinal was confirmed by using oxygen-18, showing that the reaction comprised monooxygenation, not dehydrogenation.
  • 6.6. The monooxygenase activity was inhibited by carbon monoxide, phenylisocyanide and antiNADPH-cytochrome P-450 reductase IgG, but not by anti-cytochrome b5 IgG.
  • 7.7. The enzymatic activity inhibited by carbon monoxide was photoreversibly restored by light of a wavelength of around 450 nm.
  • 8.8. The retinal-induced spectra of liver microsomes with three isomeric retinals were type I spectra.
  • 9.9. The microsomal monooxygenase activity induced by phenobarbital or ethanol were more effective than that by 3-methylcholanthrene, clotrimazole or β-naphthoflavone.
  • 10.10. These results showed that the monooxygenase reaction from retinal to retinoic acid in liver microsomes is catalyzed by a cytochrome P-450-linked monooxygenase system.
  相似文献   

11.
  • 1.1. The locust vitellogenin (VTG) receptor which is embedded in oocyte plasma membranes is a glycoprotein.
  • 2.2. With various lectins oligosaccharide units have been identified, among them neuraminic acid linked to Gal or GalNAc, mannose chains, Gal linked to GalNAc or GlcNAc and fucose linked to GlcNAc.
  • 3.3. With specific enzymes it could be shown that mannose and most other oligosaccharides are O-linked while others like fucose are N-linked.
  • 4.4. Enzymatic removal of all O-linked carbohydrates resulted in a drop of the molecular mass of the receptor protein from 200,000 to 110,000.
  • 5.5. A total of N- and O-linked oligosaccharides of 54% was calculated.
  • 6.6. The isoelectric point of the receptor was found to be at pH 3.4 increasing slightly after removal of neuraminic acid.
  • 7.7. Removal of neuraminic acids destroyed the binding ability for VTG.
  相似文献   

12.
  • 1.1. Adult Emerita talpoida were subjected to 25 temperature-salinity combinations within the range of 5–35°C and 15–65‰.
  • 2.2. E. talpoida tolerated 15–65‰ salinity at 20°C and below.
  • 3.3. Optimum salinity for survival at stressful temperatures was 40‰.
  • 4.4. Crabs transferred directly from one salinity to another experienced changes in osmoconcentration toward that of the new salinity.
  • 5.5. Temperature modified the rate of change toward the experimental salinity. Q values averaged 1.2.
  相似文献   

13.
  • 1.1. A new tetralysine endopeptidase from Escherichia coli AJ005 has been purified about 135-fold.
  • 2.2. The peptidase seems to be specific to tetralysine among lysine homopolymers.
  • 3.3. The optimal pH was about 7.5
  • 4.4. The activity was inhibited by KCN but not inhibited by soybean trypsin inhibitor.
  • 5.5. The apparent Km value was 2.5 × 1O−3 M for tetralysine.
  相似文献   

14.
  • 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   

15.
  • 1.1. Fundamental chitin digestion characteristics of Crassostrea virginica crystalline style were investigated.
  • 2.2. Optimum temperature and pH were 34°C and 4.8. respectively.
  • 3.3. The colloidal regenerated chitin (0.56mol/0.5 ml: GlcNAc equivalents) was saturating under all enzyme levels encountered.
  • 4.4. There was no evidence of end product inhibition, even after 100 hr incubation.
  • 5.5. Calculated Km for the chitinase complex was 1.19mM when determined using a 30 min assay, but was only 0.70 mM when determined using a 4.6 hr assay.
  • 6.6. Both Km values are lower than reported for similar assays in other molluscs and for most bacteria.
  • 7.7. Effect of substrate preparation on the kinetics are discussed.
  • 8.8. Eight peaks of chitinase activity were resolved by DEAE-Fractogel ion exchange chromatography.
  相似文献   

16.
  • 1.1. Lipoamide dehydrogenase was purified 1500-fold from mackerel dark muscle.
  • 2.2. The enzyme was homogeneous as judged by acrylamide gel electrophoresis in the presence and absence of SDS.
  • 3.3. Molecular weights of 102,000 and 55,000 were estimated for the native and denatured enzyme, respectively.
  • 4.4. Optimal activity for the enzyme was obtained at around pH 5.7 and enhanced with citri acid.
  • 5.5. Loss of activity was less than 5% by incubating the enzyme at 70°C for 20 min.
  • 6.6. An apparent Km of 3.1 × 10−3 M was obtained for dl-lipoic acid and 1.5 × 10−5 M for NADH.
  • 7.7. The properties of lipoamide dehydrogenase from mackerel dark muscle observed in this investigation were very similar to those reported for the enzyme from other sources.
  相似文献   

17.
Company news     
  • Daon
  • Musicrypt
  • EMI Music Canada
  • Digital Broadband Networks
  • FaceKey Corporation
  • Eystar Media Inc (EMI)
  • Temasya Wira
  • Animated Electronic Industries
  • BIO-key International
  • Entryport Corporation
  相似文献   

18.
  • 1.1. The specific activity of GMP synthetase was measured in several human tissues and found to be highest in cultured skin fibroblasts, followed by bone marrow, leukocytes, erythrocytes. placenta, and liver.
  • 2.2. The enzyme from fibroblasts was purified approximately 50-fold by ammonium sulfate fractionation and gel filtration.
  • 3.3. The Km values were determined to be 4.9μM for XMP, 270μM for ATP. and 340 μM for glutamine.
  • 4.4. Ammonium sulfate could replace glutamine as the amino donor but was much less efficient.
  • 5.5. The enzyme was specific for ATP as the energy source.
  • 6.6. Unlike the calf thymus enzyme, the human enzyme has no requirement for a reduced sulfhydryl compound.
  • 7.7. Human GMP synthetase is inhibited by ATP, dATP, azaserine, and hydroxylamine.
  相似文献   

19.
  • 1.1. An elastase-like enzyme was purified from the pyloric caeca of rainbow trout by hydrophobic interaction, cation exchange and gel-filtration chromatography.
  • 2.2. The approximate molecular weight of the elastase was 27 kDa and the isoelectric point was remarkably basic.
  • 3.3. The pH optimum of this enzyme was 8.0, when assayed with Succinyl-Ala-Ala-Ala-p-Nitroanilide.
  • 4.4. When assayed with Succinyl-Ala-Ala-Ala-p-Nitroanilide, the enzyme activity had a temperature optimum of 45°C, and the enzyme was stable up to this temperature.
  • 5.5. The trout elastase exhibited a higher specific activity than porcine elastase against Succinyl-Ala-Ala-Ala-p-Nitroanilide and elastin-orcein.
  • 6.6. The trout elastase was inhibited by elastatinal, PMSF, TPCK, SBTI and Bowman-Birk inhibitor.
  相似文献   

20.
  • 1.1. The effect of myo-inositol on the ability of three species of nematodes to survive desiccation has been studied.
  • 2.2. Survival rates obtained from worms treated with an inositol bathing medium were compared with survival rates of worms treated with distilled or tapwater media.
  • 3.3. Highest survival rates were found in those nematodes that were placed in an inositol solution prior to desiccation.
  • 4.4. Tapwater facilitated higher revival rates than did distilled water in both D. dipsaci and D. myceliophagous.
  • 5.5. No such differences were found for A. tritici.
  • 6.6. The results are discussed in relation to the possible mechanisms of protection afforded by the different bathing media.
  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