Search results for "rypsi"
showing 10 items of 240 documents
A factor derived from chick embryo retina which inhibits DNA synthesis of retina itself.
1992
Chick embryo retinas contain a peptide factor that inhibits DNA synthesis in explants of chick embryo retina. The inhibitory factor, obtained by acid/ethanol extraction from 15-day-old chick embryo retinas, was partially purified by affinity chromatography on heparin-sepharose CL-6B and gel filtration on Sephadex G-100. The inhibitor reduced DNA synthesis with maximal effects observed in retinal explants from 7 to 8-day-old chick embryos. The inhibitory effect became apparent after 10 h of incubation and reached the maximum levels after 16 h. DNA-inhibiting activity was heat and acid-stable and was destroyed by trypsin and alkaline treatments. The inhibitory effect was observed in retinal e…
Shoaling behaviour of fish under parasitism and predation risk
2008
Shoaling is a common antipredatory adaptation in several fish species. However, parasite infections may alter shoaling behaviour of fish by impairing fish sensory/motor systems and by reducing the net benefit of shoaling. In an experimental study, we investigated whether Diplostomum spathaceum (Trematoda) eye flukes alter shoaling behaviour of rainbow trout, Oncorhynchus mykiss, and if this has an interaction with predation risk. The parasite reduces the vision of fish by inducing cataract formation, which in previous studies has been shown to alter fish escape responses and crypsis. We found that the shoals of infected fish contained fewer individuals and they divided into separate groups …
Selektivit�tsstudien: OH-, NH- und SH-gruppenspezifische Reagentien - ihre Anwendung in der organischen Analytik und als Schutzgruppen in der Synthese
1992
Selectivity: OH-, NH- and SH-Groupspecific Reagents. The Application in Organic Analysis and as Protective Groups Phosphylhalides and -pseudohalides R1R2P(O)X (X = Cl, F, CN, N3, OC6H4NO2(p)) reactdepending on X- with a different selectivity with OHNH- and SH-groups. Vinylsulfones ArSO2CH = CH2 are SH-selective. Silanes R3SiH are OH-selective. By exchange of one ligand bound on P, SO2 or Si by the 5-dimethylamino resp. the 5-methoxynaphthalinogroup reagents are formed, which combine group selectivity with fluorescence. The fluorescence is quenched if a ligand or the leaving group is substituted by a NO2-group. The fluorescence appears again if after the group selective fixation the ligand w…
Cryptosporidium parvum: Structural Components of the Oocyst Wall
1999
Cryptosporidium parvum, an enteropathogenic parasite, infects a wide range of mammals including man and constitutes a substantial veterinary and medical threat due to its ubiquitous distribution and the stability of the oocyst stage. The oocyst wall of C. parvum is known to be extremely resistant to chemical and mechanical disruption. Isolated oocyst walls are shown by both thin sectioning and negative staining transmission electron microscopy to possess a filamentous array on the inner surface. This filamentous array can be greatly depleted by digestion with proteinase K and trypsin, but pepsin has less effect. Ultrasonication of the untreated oocyst walls produced almost no fragmentation,…
Occurrence and Heterogeneity of Chymotrypsin Inhibitors in Vegetative Tissues of Barley
1977
Inhibitors of chymotrypsin and the alkaline proteinase of Aspergillus oryzae were present in the shoots of barley seedlings and weak activities were also detected in the shoot tops of 6-week-old plants. Treatments which induce inhibitor formation in tomato and potato leaves had no effect when tested on mature leaves, seedlings, or young tillers of barley. Fractionation experiments with isoelectric focusing showed that the barley leaves contained several proteinase inhibitors acting on both chymotrypsin and the Aspergillus proteinase, and one inhibitor which acted only on the Aspergillus enzyme. All of these inhibitors were different from the five Aspergillus proteinase inhibitors which are …
Proteolytic cleavage of soybean Bowman-Birk inhibitor monitored by means of high-performance capillary electrophoresis. Implications for the mechanis…
1996
The hydrolysis of the soybean Bowman-Birk inhibitor in the presence of catalytic amounts of bovine trypsin and the formation of the non-covalent enzyme-inhibitor complex with an equimolar amount of enzyme are monitored by means of high-performance capillary electrophoresis (HPCE). The inhibitor is cleaved in the trypsin-reactive and more slowly in the chymotrypsin-reactive subdomain. HPCE proves itself as the only reliable analytical tool to monitor these reactions in clear contrast to classical electrophoretic, chromatographic and enzymatic methods. The most efficient separation of the intact and the two active site cleaved forms of the inhibitor was achieved in borate buffer at pH 10.0. T…
Regulation of chitin synthase activity inSaccharomyces cerevisiae: Effect of the inhibition of cell division and of synthesis of RNA and protein
1980
The effect of pronase and trypsin on the activation or deactivation (degradation?) of chitin synthase ofSaccharomyces cerevisiae occurs faster in membranous preparations than in toluene-treated cells. When the temperature is raised, the former preparation is deactivated earlier than the latter one. The activity found in growing cells is not modified after inhibition of protein synthesis by cycloheximide or amino acid starvation or by the inhibition of RNA synthesis. It was possible to activate the chitin synthase ofS. cerevisiae cdc 25 grown at 23°C by means of pronase, whereas trypsin had no effect. After the cells were grown at 37°C, chitin synthase could not be activated either with tryp…
Preparative separation of proteins and enzymes in the mean molecular-weight range of 10,000–100,000 LiChrosorb diol® packing by high-performance size…
1979
Abstract LiChrossorb Diol® packing has been to be well-suited for the separation of proteins and enzymes according to a size-exclusion mechanism in a mean molecular-weight (MW) range between 10,000 and 100,000. Loadability of a small bore column of 6 mm I.D. (A) and a large-bore column of 23.5 mm I.D. (B), both of 250 mm in length, were examined. Defining a 20% decrease of the number of theoretical plates as loadability limit the volume load at constant mass of chymotrypsinogen as representative test solute was ≈ 100 μl for column (A) and 1500 μl for column B at 0.78 · 10-5 g/g of packing for column A and 0.78 · 10-6 g/g of packing for column B, respectively. Mass load to constant injection…
Inhibitors of endogenous proteinases in the seeds of Scots pine, Pinus sylvestris
1980
Extracts of resting pine seeds inhibited the proteinase activities present in extracts of endosperms of germinating seeds (hydrolysis of haemoglobin at pH 3.7 and hydrolysis of casein at pH 5.4 and 7.0). Heating the extracts of resting seeds at 60°C destroyed their own proteinase activity but their proteinase inhibitor activity decreased by only 25 to 30%. Some properties of the inhibitor(s) were studied using extracts treated at 60°C. The inhibitor activities were non-dialysable. the inhibition increased linearly with increasing inhibitor concentration up to 80% of total proteinase activity, and the maximal inhibition was 80% at pH 3.7. 90% at pH 5.4. and 97% at pH 7.0. The extracts of res…
Limited Proteolysis of Human α2-HS Glycoprotein/Fetuin
1996
alpha2-HS glycoprotein is a major protein of human plasma whose function is still obscure. A proteolytically processed form of alpha2-HS glycoprotein lacking a segment of 40 amino acid residues bridging its heavy and light chain portions ("connecting peptide") has been described suggesting that this peptide is released by post-translational processing to fulfill biological role(s) of alpha2-HS glycoprotein. To test this hypothesis we investigated how the connecting peptide is released from the parental molecule by limited proteolysis. We developed monoclonal antibodies to various portions of the connecting peptide and its NH2-terminal flanking region which cross-react with the native alpha2…