A novel biocatalytic reaction of transamidation of non-activated amides with amines is reported. Among 45 different lipolytic and proteolytic enzymes tested, only the lipase from Candida antarcticawas able to catalyze this reaction. The reaction proceeded with up to ca. 80% conversion in anhydrous methyl tert-butyl ether and worked with both N-substituted and unsubstituted amides. The biocatalytic transamidation is an equilibrium process and, therefore, higher conversions to the desired amide were achieved by using increased concentrations of the amine nucleophile. 相似文献
35S-lipoic acid (20 mumol/kg) with different doses of thiamine or 35S-thiamine (50 mumol/kg) with unlabelled lipoic acid where administrated to the white mice stomach. It was established that absorption and entrance of both lipoic acid and thiamine when they were in 1:5 quantities in organs and tissues were maximal. The activity of Na+, K-ATPase determined in stomach, duodenum and small intestine was the maximal too. 相似文献
Rabbits were immunized by homogenates of endometrium obtained from women during 10-12 weeks of gestation. A specific antiserum was obtained by absorption of the crude antiserum by blood cells and plasma proteins of men with different kinds of ABO and Rh antigens, till disappearance of positive reaction with men's serum protein in the Ouchterlony test. Such an adsorbed specific antiserum continued to react with the sera of pregnant women. Two antigens, numbers 1 and 2, respectively, were determined by the Ouchterlony test. Another group of rabbits was immunized by antigens detected in the precipitation test. A monospecific antidecidual antiserum (ADS 1092) was obtained against number 2 antigens. This antiserum revealed only one antigen in sera of women with gestation and did not react with sera of non-pregnant women. In the slides of endometrium of pregnant women of 10-12 weeks of gestation ADS 1092 had a strong positive reactive with the cytoplasm of one type of endometrium cells. The immunomorphological analysis by the non-direct Coons test and the PAP-test permits to identify cells with the positive reaction as granular cells. It is concluded that the granular cells may be a source of one of the serum antigens detected in women with gestation. 相似文献
The deterministic model of microevolutionary dynamics of “phagebacteria” ecosystem is analyzed. Primary (and after all decisive) events that determine the dynamics are direct interactions between bacterial reception and viral adsorption proteins. Structure of the model is that under real parameters of adsorption, lysis and reproduction each separate (ith) stage of microevolution comes to end with total lysis of ith population of bacteria by ith population of phage. It is shown however that in the course of joint microevolution both populations pass over some critical sizes when a new pair of antagonistic strains arises with certainty from mutations. As a result it is easy to visualize and simulate by computer the process of successive fixations of such pairs of mutants. This coevolution is the original example of a locally adaptive but globally undirected process which is characterized also by: (1) constant average rate, (2) neutrality of mutations at the moment of their emergence and during the period of “anticipation” of ecological changes, (3) pure adaptivity of the same mutations at the moment of proper fixation and (4) “intrinsic origin” (from the ecosystem dynamics itself) of selective constraints. 相似文献
DNA fingerprinting, followed by multivariate analysis of data, was used to characterize genetic heterogeneity in captive populations of the endangered Siberian and sandhill cranes. The genetic structure revealed reflected the natural population and species distributions. The relevant groups differed not only from each other, but also from interspecies and inter-population hybrids bred in captivity. In this study we have tested an approach to the analysis of population structure based on individual genotypes. Interpretation of fingerprinting data by means of the analytical system applied here is a useful and reliable procedure for the estimation of genetic relationships between individuals. 相似文献
Balloon pre-dilation is usually performed before implantation of a nitinol stent in a femoropopliteal artery in a case of severe blockage or calcified plaque. However, its effect on performance of the nitinol stent in a diseased femoropopliteal artery has not been studied yet. This study compares the outcomes of stenting with pre-dilation and without it by modelling the entire processes of stent deployment. Fatigue deformation of the implanted stent is also modelled under diastolic–systolic blood pressure, repetitive bending, torsion, axial compression and their combination. Reduced level of stress in the stent occurs after stenting with pre-dilation, but causing the increased damage in the media layer, i.e. the middle layer of the arterial wall. Generally, pre-dilation increases the risk of nitinol stent’s fatigue failure. Additionally, the development of in-stent restenosis is predicted based on the stenting-induced tissue damage in the media layer, and no severe mechanical irritation is induced to the media layer by pre-dilation, stent deployment or fatigue loading.