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PubMed1977

Altered humoral immune response to sheep red blood cells by sheep erythrocyte-soluble hemolysate.

Adult C3H/He mice were rendered unresponsive to a primary injection of sheep red blood cells (SRBC) by pretreatment with sheep hemolysate supernatant (SHS) or subfractions of SHS isolated by column chromatography. The following effects of SHS on the immune response were observed: SHS did not kill antigen-reactive cells, it did not prevent the release of antibody by cells actively synthesizing and secreting antibody, and SHS-induced tolerance was not inhibited or abrogated by methods which terminate or abolish tolerance. In addition, cell-mediated responses were not affected in animals whose humoral responses were suppressed; however, the secondary plaque-forming cell (PFC) response was enhanced by SHS treatment. SDS gel electrophoresis revealed SHS to contain several proteins ranging from 12,000 to approximately 500,000 daltons.

Animals↗
PubMed1976

Studies on the immune response to fixed antigens. Preferential induction of helper function with heavily trinitrophenylated sheep erythrocytes, and glutaraldehyde-treated sheep erythrocytes.

Mice primed with heavily trinitrophenylated sheep red cells (TNP128SRC) or glutaraldehyde-treated sheep red cells (G-SRC) developed an early helper function mediated by thymus-derived cells. Such mice were able to produce high secondary responses to both hapten and carrier after challenge 2 days after priming, with lightly trinitrophenylated SRC (TNP0.14SRC). However, the primary response of the TNP128SRC or G-SRC-primed mice were very low to undetectable, and their secondary responses were also low when the challenge antigen was administered 4 days after priming or later. Inhibitory humoral factor(s) which were induced in the primed animals appeared responsible for the decreased capacity of primed mice to mount a secondary response when challenged later than 2 days after priming. Transfer of spleen cells from TNP128SRC-primed mice to sublethally irradiated recipients circumvents their exposure to inhibitory humoral factor(s) present in intact animals allowing them to react with challenge antigen. Enriched populations of T cells, but not B cells, were able to transfer this early immunologic memory to irradiated recipients. The theoretical and practical implications of these results are discussed.

Aldehydes↗
PubMed1978

Methionyl-tRNA synthetase from sheep liver. Purification of a fully active monomer derived from high-molecular-weight complexes by trypsin treatment. Evidence for immunological cross-reaction with the corresponding enzyme from sheep mammary gland.

The size distribution of methionyl-tRNA synthetase in extracts from sheep liver is compared to that of lysyl-tRNA, isoleucyl-tRNA, leucyl-tRNA and seryl-tRNA synthetases by gel filtration on Biogel A-5m. Extraction conditions are described which lead to isolation of methionyl-tRNA synthetase exclusively in the form of complexes of molecular weight close to 10(6). Limited trypsin treatment of these aggregates releases a fully active low-molecular-weight form of methionyl-tRNA synthetase which was purified to a specific activity of 674 units/mg at 25 degrees C with a yield of 40%. The homogeneous enzyme appears to be undistinguishable from the corresponding enzyme derived from sheep lactating mammary gland, as judged by acrylamide gel electrophoresis in the presence of sodium dodecyl sulfate and by titration with antibodies raised against the enzyme purified from liver.

Amino Acyl-tRNA Synthetases↗
PubMed1979

The prevalence of Sarcocytis spp in dogs, foxes and sheep and Toxoplasma gondii in sheep and the use of the indirect haemagglutination reaction in serodiagnosis.

Sporocysts of Sarcocystis spp were found in the faeces of 39.3 per cent and 25 per cent of farm dogs and foxes respectively. The indirect haemagglutination serodiagnostic test suggested that nearly all sheep in the area sampled became infected early in life and diagnosis of infection by this means correlates well with trichinoscopy findings. The sarcocystis antigens used in serodiagnostic tests did not cross react with sera positive for Toxoplasma gondii. Sarcocystis antigens derived from cattle cross reacted with ovine sera but comparative tests showed the titres to be less than where the homologous antigen was used.

Animals↗
PubMed1979

Study of gastro-intestinal stronglyosis in a sheep flock on permanent pasture. 1. Sheep parasitism in 1977.

An epidemiological study aimed at defining gastro-intestinal parasitism in sheep qualitatively and quantitatively was carried out in the Limousin area in France. Five lambs were sacrificed regularly every 4 weeks from May till January of the following year. Complete parasite counts were performed on these animals as well as measurements of the plasma level of pepsinogen. In order to define the influence of parasitism on the growth of the animals, the weight gains of lambs treated regularly and untreated lambs were compared. The results of post-mortem examination show that parasitism is mainly linked to the incidence of strongyles. Other observations in the flock have shown that Moniezosis may also play a non-negligeable part. The parasitic level, already high after one month at pasture, reached its maximum in July-August 1977 and was marked by a very high level of parasitism. Among these species found, two played an essential part: Ostertagia circumcincta and Haemonchus contortus. A study of the growth of the lambs showed that within 6 months, the weight gain of the treated animals was twice that of the untreated animals. The effects of parasitism were worsened by the low fodder value of the pasture and the occurrence of overgrazing. The blood pepsinogen measurements confirmed the usefulness of this technique in establishing the mean level of infestation of a flock by parasites of the abomasum. It seems that in some cases it could help to define the succession of peaks of infestation by different species.

Animal Nutritional Physiological Phenomena↗
PubMed1977

Changes in ultrastructure and function of the sheep pigment epithelium and retina induced by sodium iodate. I. The ultrastructure of the normal pigment epithelium of the sheep.

The normal ultrastructure of the sheep pigment epithelial cells is described as a basis for the interpretation of toxic (sodium iodate) effects on these cells dealt with in two following papers. The morphological features of the different cell membranes and cell organelles, particularly the phagosomes and the lipid droplets, are discussed in relation to renewal of the photoreceptor outer segment, pigment epithelial and retinal metabolism, barrier mechanisms and electrical properties.

Animals↗
PubMed1978

[Residues of the antifluke preparations, dovenix and acredist, in sheep milk and their effect on the biochemical blood indices of sheep].

The excretion of residual amounts of acedist and dovenix with the milk of sheep that had been treated with these preparations was established on the 24th, resp., up to the 27th day following treatment, though their presence in the milk was found to drop sharply after the third day. The treatment with acedist led to a dependable decrease (P less than 0.05) in the hemoglobin amount, the total protein, and the erythrocyte count, and a dependable increase (P less than 0.05) in the leukocyte count. The intensity of these changes subsided parallel to the decrease in the residual amounts of the preparation in the milk excreted. The treatment with dovenix did not result in any deviations of the indices refered to.

Animals↗
PubMed1975

[Studies on the properties of acid erythrocyte phosphatase in sheep and the isoenzymes of sheep and goat acid erythrocyte phosphatase].

Ovine erythrocytic acid phosphatase showed two peaks of activity at pH 5.0 and 5.7 in acetate buffer with p-nitrophenylphosphate as substrate. The enzyme was only slightly inhibited by fluoride and L-phenylalanine, but high concentrations of urea strongly inhibited it. Activity of the enzyme was greater in goat erythrocytes than in sheep. By means of starch electrophoresis, three isoenzymes belonging to nine types were separated from the ovine enzymes, while three isoenzymes of five types were present in goats. Electrophoresis in polyacrylamide gel was suitable for detecting the rapidly migrating isoenzymes.

Acid Phosphatase↗
PubMed1977

Hemoglobin switching in sheep and goats. Preparation and characterization of complementary DNAs specific for the alpha-, beta-, and gamma-globin messenger RNAs of sheep.

Specific complementary DNAs (cDNAs) for the messenger RNAs coding for sheep alpha-, betaA-, betaB-, betaC-, and gamma-globins were prepared by thermal denaturation of heterologous hybrids (e.g. alphabetaB-cDNA-alphagamma-mRNA) followed by hydroxylapatite chromatography. Each cDNA represented a nearly full-length copy of its globin mRNA complement as determined by electrophoretic analysis in polyacrylamide gels containing 98% formamide. The purity of each cDNA fraction was estimated by hybridization analysis and thermal denaturation. The beta- and gamma-cDNAs contained 5 to 20% contaminating alpha-cDNA while the alpha-cDNA was 25 to 30% contaminated with non-alpha-cDNA. The melting temperatures (Tm) of homologous duplexes between each non-alpha chain cDNA and its mRNA complement ranged from 69.5-71.5 degrees in 50% formamide while alpha-alpha duplexes melted with a Tm of 75-76 degrees. The Tm values of heterologous duplexes formed between each non-alpha-cDNA and the various globin mRNAs (e.g. betaB-cDNA-Hb C mRNA) ranged between 64.5 degrees and 68 degrees and thus were only 1.5-5.0degrees below that of homologous duplexes. These results suggest that the nucleotide sequence divergence among the various non-alpha-mRNAs (or cDNAs) is not greatly different from the minimum predicted from the amino acid sequence differences of the corresponding globins. When annealing reactions were performed above the Tm of the heterologous hybrids (68 degrees), each non-alpha-cDNA hybridized only to its own complementary mRNA. Thus the purified cDNAs provide molecular probes for the quantitation of alpha-, beta-, and gamma-globin-specific nucleotide sequences.

Animals↗
PubMed1977

Sulphur-selenium studies in sheep. I. The effects of varying dietary sulphate and selenomethionine on sulphur, nitrogen and selenium metabolism in sheep.

Sulphur, selenium and nitrogen metabolism were studied in Merino wethers fed for 35-day periods on semipurified diets in which the sulphur content was increased to either 0-07 or 0-20% by the addition of sodium sulphate. At both levels of sulphur, additions of selenium as DL-selenomethionine increased the basal level of selenium (0-02 microgram/g) to 0-06, 0-09 and 0-67 microgram/g. Both levels of dietary sulphur supported positive sulphur balances but a reduction in sulphur intake per se resulted in a significant depression in dry matter digestibility (P less than 0-05), apparent nitrogen digestibility (P less than 0-05), nitrogen balance (P less than 0-01), sulphur balance (P less than 0-05) and plasma sulphate-sulphur (P less than 0-05) and wool (P less than 0-01) selenium levels. Selenium balance was not affected by differences in sulphate-sulphur intake. Selenium balances (P less than 0-001), plus the selenium levels in plasma (P less than 0-001), and wool (P less than 0-001) were significantly different at the different levels of selenium supplementation. A positive selenium balance was achieved when the selenium intake was approximately 37 microgram/day, regardless of sulphur treatment. The validity of using plasma and/or wool selenium levels as indices of the selenium status of sheep is questioned.

Animals↗
PubMed1976

Inhibitory effect of sheep erythrocyte fragments on rosette formation of human T lymphocytes with sheep red blood cells.

The effect of sheep red blood cells (SRBC) fragments on rosette formation of human peripheral T lymphocytes with SRBC was evaluated on the active and total T-rosette tests. The rosetting capacity of active rosette-forming cells was selectively and nearly completely inhibited by the pretreatment of lymphocytes with SRBC fragments. The decrease in total rosettes by blocking with SRBC fragments was almost parallel to that of active rosettes. SRBC fragments had no inhibitory effect on the rosetting capacity of a lymphocyte population in which active rosette-forming cells were removed by gradient centrifugation. These results suggested that active rosette-forming cells in human T lymphocytes have the receptors of high affinity for SRBC and these receptors readily bind SRBC fragments, resulting in block of rosette formation.

Animals↗