Rapid increases in the membrane expression of neutral endopeptidase (CD10), aminopeptidase N (CD13), tyrosine phosphatase (CD45), and Fc gamma-RIII (CD16) upon stimulation of human peripheral leukocytes with human C5a.

Rapid increases in the membrane expression of C3 receptors on granulocytes and monocytes in response to the anaphylatoxin C5a have previously been described. In this study we demonstrate increases in the membrane expression of neutral endopeptidase (NEP, CD10, CALLA), aminopeptidase N (APN, CD13), tyrosine phosphatase (CD45/CD45Ro) and the Fc R Fc gamma-RIII (CD16) on granulocytes within minutes of treatment with human C5a. Monocytes responded to C5a with increases in CD13 and CD45/CD45Ro. These membrane modulations could be prevented by preincubating the C5a preparations with anti-C5a mAb C17/5 but not by pretreating the cells with cycloheximide. Increases of CD10, CD13, and CD11b but not CD11a (LFA-1) were also observed in leukocytes from patients undergoing hemodialysis with cuprophan membranes. The increase of CD16 on granulocytes was dependent on the presence of plasma during in vitro activation with C5a indicating that plasma contains inhibitors which prevent the previously described loss of Fc gamma-RIII upon stimulation of the cells.     

Equilibrium and kinetic studies of the binding of tri- and tetra-anionic ligands to bovine serum albumin.

The binding of tri- and tetra-anionic azo dyes (Amaranth, Ponceau 4R, and Ponceau 6R) to bovine serum albumin (BSA) at pH = 7.0 and 25 degrees C has been studied by equilibrium dialysis, spectrophotometry, and by stopped-flow and temperature-jump methods. Equilibrium dialysis revealed that BSA has one primary binding site and about two secondary sites for each dye. The values of the binding constant for the primary site show that the stability of the complex at the primary site progressively increases with an increase in the number and the density of anionic charges on ligand. Kinetic data have been found to be consistent with a scheme in which a rapid bimolecular binding is followed by two isomerizations of the complex (in the case of Amaranth) or by one isomerization (in the cases of Ponceau 4R and Ponceau 6R). Equilibrium and rate constants for each step of the scheme were determined. From the results it was found that the increment of the number and the density of anionic charges on ligand accelerates the forward process of the final isomerization step but retards the backward one of it, resulting in the enhancement of the stability of the complex at the primary site. On the basis of these results and the structure of the ligands, the detailed binding mechanism has been discussed in the light of the electrostatic interaction between the ligands and the binding site on BSA.     

A SNP/microsatellite genetic linkage map of the Atlantic cod (Gadus morhua)

A first genetic linkage map of the Atlantic cod ( Gadus morhua ) was produced, based on segregation data from 12 full-sib families of Norwegian origin. The map contained 174 single nucleotide polymorphism markers and 33 microsatellites, distributed on 25 linkage groups and had a length of 1225 cM. A significant difference in recombination rates between sexes was found, the average ratio of female:male recombination rates being 1.78 ± 1.62 (SD).     

Effector mechanisms in allograft rejection. IV. In contrast to late cytotoxic cells, and early killer cells infiltrating mouse sponge matrix allografts are predominantly T lymphocytes.

We have earlier demonstrated that a mixed population of immunologically specific killer cells, including cytotoxic T lymphocytes, non-T (“B”) lymphocytes and monocytes, infiltrate “sponge matrix” allografts at the peak of rejection on Day 8 after transplantation. We have now performed a sequential study covering both early and late stages of the rejection response. We demonstrate that the early infiltrating killer cells are sensitive to anti-Ø and anti-T cell serum plus complement treatment but the late killer cells are not. This finding indicates that the first cytotoxic host cells infiltrating the allograft are predominantly T lymphocytes, whereas as the rejection process proceeds also cytotoxic non-T (“B”) lymphocytes and monocytes are recruited to the site of inflammation.     

Effects of adrenoceptor blockade on cardiac hypertrophy and myocardial phospholipids.

Catecholamines have been proposed as a stimulus for the hypertrophic response to pressure overload of the heart and could also mediate the membrane lipid changes associated with cardiac hypertrophy. To address both of these possibilities, cardiac hypertrophy was induced by aortic constriction in the presence or absence of chronic alpha- or beta-adrenoceptor blockade. Heart weights and heart weight to body weight ratios in aortic-constricted rats of the adrenoceptor-blocked and vehicle-treated groups were elevated to the same extent when compared with values in sham-operated rats of each group. Analysis of the fatty acyl composition of the major phospholipid classes revealed that similar changes occurred in vehicle-treated, alpha-blocked, and beta-blocked aortic-constricted rats when compared with respective groups of sham-operated rats. Specifically, linoleic acid was reduced in the phosphatidylcholine, phosphatidylethanolamine (PE), and cardiolipin (CL) fractions in all groups of aortic-constricted rats. This reduction was accompanied by increased docosahexaenoic acid, arachidonic acid, or palmitic acid in phosphatidylcholine; docosahexaenoic acid in phosphatidylethanolamine; and oleic acid in cardiolipin fractions. Adrenoceptor blockade did not prevent or attenuate the major changes in the fatty acyl composition of phospholipids or the increase in heart weight associated with aortic constriction. This suggests that a change in the level of adrenoceptor stimulation is not the stimulus for cardiac hypertrophy or the observed alterations in phospholipid composition in the pressure-overloaded rat heart.     

Characteristics of the range of mutations in nystatin resistance induced in yeasts by 6-N-hydroxylaminopurine

A simple procedure for induction of nistatin-resistant mutants in yeasts under the action of 6-N-hydroxylaminopurine (HAP) is proposed. Some differences between the spectra of mutations induced by HAP and UV-light are observed: HAP induces dominant and double recessive mutants more frequently.