Association of the M blood group system with bovine mastitis

Associations of the 11 bovine blood group systems with mastitis were examined in Red Danish dairy cattle. The mastitis status was followed during three lactational periods. A significant effect of the M blood group system on mastitis incidence was observed in the first and second lactation periods and a lower frequency of mastitis is found among animals lacking the M' factor as compared to those having the M' blood group factor. The significance of these results are discussed in view of the close relation between the M blood group system and the bovine lymphocyte antigens (BoLA), and the expected effect of eliminating the M' gene from the breed is estimated. Among the remaining 10 blood group systems, the T' system was the only system showing an overall effect on mastitis, and only in first and third lactation. However, the T' system was inconsistent with regard to the effect of the T' gene on the various mastitis diagnoses.     

Influence of pregnancy and sex steroids on concentration, motor effect and receptor binding of VIP in the rabbit female genital tract

The influence of sex steroid and pregnancy on the tissue concentration, uterine motor effect and receptor binding of VIP has been studied in the female genital tract of pregnant rabbits and oophorectomized rabbits during progesterone and/or oestrogen substitution. The concentration of immunoreactive VIP was high in the vagina and cervix, and lower in the uterine body of both pregnant and non-pregnant rabbits. A significant decrease in the VIP concentration (pmol/g wet weight) of the uterine body was observed toward term of pregnancy. The total uterine content of VIP, however, seems unchanged. Treatment of oophorectomized rabbits with ovarian steroids had no effect on the VIP concentration. The sensitivity for and potency of VIP on the relaxation of uterine muscle was significantly higher in oophorectomized rabbits treated with a combination of progesterone and oestrogen than in control rabbits. No difference was observed between non-pregnant and pregnant rabbits. The degradation and binding affinity for 125I-labelled VIP was highest in oophorectomized rabbits substituted with both oestrogen and progesterone. In the pregnant rabbits, the amount of receptors was decreased near term. In conclusion, sex steroids are able to influence the motor effect of VIP at the receptor level, but have no effect on the VIP concentration in the female genital tract.     

Differences in reactivity of confluent and nonconfluent cultures of human endothelial cells toward thrombin-stimulated platelets or heparinized salt solution

Summary This study examined whether nonconfluent endothelial cell cultures reacted differently than confluent ones toward thrombin-stimulated platelets or a heparinized salt solution. The adherence to the endothelial cell cultures of⁵¹Cr-labeled human platelets stimulated at different thrombin concentrations was studied. There was significantly higher adherence of stimulated platelets to nonconfluent cultures compared with confluent ones. This was confirmed by scanning electron microscopy, which also revealed a tendency for the platelets to adhere at the cell periphery. Electron microscopy also showed that thrombin-stimulated platelets induced endothelial cell contraction. Part of the peripheral endothelial cell surface toward the bottom of the culture dish was inverted, facing the lumen of the dish. This phenomenon was particularly seen in nonconfluent cultures. When⁵¹Cr-labeled endothelial cultures were incubated with a mildly injurious fluid as heparinized sodium acetate and 20% serum, at 20° C for 30 min, the nonconfluent cultures showed significantly more cell detachment and release of⁵¹Cr than the confluent ones. We conclude that under the conditions of the present experiments there are differences in the reactivity of confluent and nonconfluent endothelial cell cultures. These differences probably reflect biological dissimilarities. In experiments where properties of cultured endothelium are studied, care should be taken that the degree of confluency is standardized.     

Immunological comparison of glyoxalase I from yeast and mammals and quantitative determination of the enzyme in human tissues by radioimmunoassay

Antibodies to glyoxalase I from yeast, rat liver, porcine erythrocytes and human erythrocytes were raised in rabbits. Gel precipitation and immunotitration experiments demonstrated that the mammalian enzymes were immunologically related, but distinct from the yeast enzyme. Fab fragments of the antibodies to human glyoxalase I did not inhibit the catalytic activity, indicating that the antigen binding sites were not directed towards the active site of the enzyme. A radioimmunoassay for glyoxalase I was developed. Quantitative analysis of human adult as well as fetal organs demonstrated that glyoxalase I was present in a concentration of approximately 0.2 micrograms/mg protein in most human tissues.     

Analysis and detection of chlamydial DNA

Elementary bodies of lymphogranuloma venereum (LGV) strains of Chlamydia trachomatis contain, in addition to the genomic DNA, a 6.7 kb plasmid. The plasmid from serovar L2 (434-B) was cloned at the BamHI site of pBR327 into Escherichia coli and a restriction cleavage map of this pLGV125 recombinant plasmid determined. All 15 C. trachomatis serovars contained DNA sequences that hybridized with pLGV125. When total DNA from L2 elementary bodies was used as a probe in Southern blotting and spot hybridization, serovars L1, L2 and L3 exhibited significant homology. The detection level of homologous DNA was 100 pg and LGV DNA was detectable in infected cells when total L2 probe was used in the nucleic acid hybridization test. These DNA probes may be useful as investigative and diagnostic reagents for C. trachomatis.     

Expression of nodule-specific uricase in soybean callus tissue is regulated by oxygen

In soybean root nodules the enzyme uricase is expressed concomitantly with nodule development. The initial expression of this protein does not depend on active nitrogen fixation, as demonstrated by analysis of uricase activity in effective and ineffective root nodules. However, the maximal level of uricase activity is determined by the infecting Rhizobium japonicum strain. Sterile root cultures and callus tissue, devoid of the microsymbiont, were incubated at varying oxygen concentrations and analyzed for uricase activity. The specific activity of uricase was increased by lowering the oxygen concentration, with the highest activity obtained around 4−5% oxygen. The increase in uricase activity was due to increased uricase synthesis, as demonstrated by in vivo labelling of callus culture followed by immunoprecipitation with antibodies raised against highly purified nodule uricase.     

Nucleotide sequence of the CytR regulatory gene of E. coli K-12.

We have determined the nucleotide sequence of the cytR gene, which codes for the Cyt repressor (CytR). The coding region consists of 1023 or 1029 bp. The subunits of CytR are thus predicted to consist of 341 or 343 residues. It is shown that the N-terminal segment of the polypeptide is structurally similar to the DNA-binding region of known DNA-binding proteins. In addition, there exists an exceptionally high amino acid sequence homology between CytR and the Gal repressor, indicating a common origin of evolution.