Measurement of glycosaminoglycans and keratan sulphate in canine arthropathies

Glycosaminoglycans (gag) and keratan sulphate (ks) were measured in sera and synovial fluids from dogs with either osteoarthritis (oa) or rupture of the cranial cruciate ligament (ccl) and normal dogs. The dogs with oa had higher synovial fluid gag levels (P<0·002) and serum KS (P<0·03) compared to the normal dogs. No significant differences in serum gag were found in either group. In both oa and rupture of the ccl, gag levels were increased in the synovial fluid from the affected joint compared with the clinically normal (inactive) contralateral joint. Neither gag nor ks measurements correlated with serum and synovial fluid antibodies to collagen type II, synovial fluid white cell count or age of dog. It is unlikely that the measurement of these cartilage breakdown products is of value for diagnostic or prognostic use in canine arthropathies.     

Inheritance and reliability of random amplified polymorphic DNA-markers in two consecutive generations of common carp (Cyprinus carpio L.)

Random amplified polymorphic DNA (RAPD) markers have been used in a variety of genetic studies in fisheries and aquaculture. Most population studies are performed without preliminary data demonstrating the Mendelian inheritance and reproducibility of RAPD markers. In this study, the inheritance and reproducibility of RAPD markers was examined in two consecutive generations of common carp, Cyprinus carpio L. Variability and segregation of RAPD markers were investigated in one F₁ progeny and three F₂ progenies. Seventy-four RAPD markers were generated by five primers using DNA extracted from the initial ornamental (koi) common carp female and wild-type colour common carp male. Fifty-five of these RAPD markers were transmitted to the F₁ progeny and the inheritance patterns were analysed. Twenty RAPD markers were fully reproducible and demonstrated dominant simple Mendelian inheritance patterns in two consecutive generations. Twenty-four RAPD markers were not reproducible in all progenies. Thirteen markers displayed inheritance ratios in the progenies that did not fit simple Mendelian inheritance patterns. Non-reproducibility of RAPD markers and distorted ratios may be caused by the absence of amplification, poor amplification or by the appearance of artefact bands. Random amplified polymorphic DNA markers with poor reproducibility and non-Mendelian inheritance can lead to misinterpretations of data in population studies, resulting in errors in the estimation of genetic diversity within and between individual populations. Therefore, it is recommended to first identify the set of reproducible RAPD markers that demonstrate Mendelian inheritance before application of the RAPD technique in population studies.     

Regulation of urease production in soil by microbial assimilation of nitrogen

Summary Studies of the effects of different forms of N on urease production in soils amended with organic C showed that although microbial activity, as measured by CO₂ production, was stimulated by the addition of NH₄ ⁺ or NO₃ ^- to C-amended soils (200 mol glucose-C g^–1 soil), urease production was repressed by these forms of N. The addition of L-methionine sulfoximine, an inhibitor of inorganic N assimilation by microorganisms, relieved the NH₄ ⁺ and NO₃ ^- repression of urease production in C-amended soil. The addition of sodium chlorate, an inhibitor of NO₃ ^- reduction to NH₄ ⁺ by microorganisms, relieved the NO₃ ^- repression of urease production, but did not eliminate the repression associated with NH₄ ⁺. These observations indicate that microbial production of urease in C-amended soils is not directly repressed by NH₄ ⁺ or NO₃ ^-, but by products formed by microbial assimilation of these forms of N. This conclusion is supported by our finding that the biologically active L-isomers of alanine, arginine, asparagine, aspartate, and glutamine, repressed urease production in C-amended soil, whereas the D-isomers of these amino acids had little or no influence on urease production. This work suggests that urease synthesis by soil microorganisms is controlled by the global N regulon.     

Effects of pasteurization of colostrum on subsequent serum lactoferrin concentration and neutrophil superoxide production in calves

OBJECTIVE: To determine the effects of pasteurization of colostrum on serum lactoferrin concentration and neutrophil oxidative function by comparing values from calves given pasteurized (76 C, 15 minutes) colostrum versus calves given fresh frozen colostrum. ANIMALS: 8 Holstein bull calves were used to study the effects of pasteurization of colostrum on the absorption of lactoferrin and neutrophil oxidative burst. Three additional calves were used to study the effect of exogenous lactoferrin on neutrophil oxidative burst. METHODS: Calves were fed fresh frozen or heat pasteurized colostrum (76 C for 15 minutes) via esophageal feeder within 4 hours of birth. Neutrophils were isolated from whole blood samples. Neutrophil oxidative burst was induced by phorbol ester (300 ng/ml) stimulation of cells (1 X 10(6) cells) at 37 C. Serum lactoferrin concentrations were compared, using immunoblot analysis. Serum IgG concentrations were determined by radial immunoassay. Comparisons were made between the use of the 2 types of colostrum in calves by measuring subsequent serum IgG and lactoferrin concentrations and neutrophil superoxide production. RESULTS: Serum IgG and lactoferrin concentrations increased more in calves receiving fresh frozen colostrum. Neutrophil superoxide production was higher in neutrophils prepared from calves receiving fresh frozen colostrum. Colostral lactoferrin addition to neutrophil incubations resulted in increased oxidative burst. CONCLUSIONS AND CLINICAL RELEVANCE: Compared with calves given fresh frozen colostrum, calves given pasteurized colostrum had decreased serum IgG and lactoferrin concentrations and neutrophil superoxide production 24 hours after administration. These results suggest that pasteurizing bovine colostrum at 76 C for 15 minutes has substantial effects on passive transfer of proteins and neutrophil function.     

Effects of hexavalent chromium on development of crabs,Rhithropanopeus harrisii and Callinectes sapidus

Survival of Rhithropanopeus harrisii larvae from hatching to first crab stage occurred in Na₂CrO₄ concentrations from 1.1 to 29.1 ppm. Estimated LC50 for complete zoeal development was 17.8 ppm Na₂CrO₄ and it was 13.7 ppm for development to first crab stage. A concentration of 1.1 ppm Na₂CrO₄ was nontoxic, while Na₂CrO₄ concentrations of 7.2 and 14.5 ppm were sublethal and concentrations of 29.1 to 58.1 ppm were acutely toxic. Low concentrations of Na₂Cr0₄ caused an increase in swimming speed and high concentrations caused a decline. Survival of Callinectes sapidus larvae occurred in Na₂CrO₄ concentrations from 1.1 to 4.7 ppm. The LC50 for complete zoeal development was estimated to be 2.9 ppm Na₂CrO₄ and the LC50 for development to first crab stage was estimated to be 1.0 ppm Na₂CrO₄ The total Cr in sodium chromate is 32% by weight (Tacey,1981), hence, the total Cr concentrations tested were 32% of the Cr salts given above. Statistical analyses of the data on survival, duration and mortality of larvae are presented.     

Analysis of a site x year experiment with timothy polycross progeny

Summary Results from a cooperative breeding programme with timothy for the northern areas of Scandinavia are presented. The main aim of the programme was to identify genotypes for synthetic populations that are high yielding, adapted over the whole area and stable over years. A polycross comprising 12 genotypes from each of five sites within the region was formed. The subsequent 60 half-sib families and four reference varieties were then compared under sward conditions at the same sites. The trials lasted for three years and results for total dry matter yields are presented.Significant differences in yield between lines were found. There were also significant two and three factor interactions between lines, sites and years. A new two-step procedure is presented to select the genotypes to make up a synthetic variety. Firstly, a superiority measure (Q-value) is used to select a group of genotypes that are high yielding and stable over sites and years. Secondly, the GxE part of the Q-value is split into two terms. One measures adaptation to predictable environmental conditions. The other one measures stability to unpredictable changes in the environment. A plot of these two measures provides a tool for discarding unstable or poorly adapted genotypes. The statistical properties of the selection parameters are discussed.     

Epidemiology of porcine non-specific colitis on Scottish farms

The objective of this study was to investigate epidemiological risk factors for porcine non-specific colitis (NSC). Forty-seven Scottish pig farms, with and without a clinical history of diarrhoea during the growing period (15-40 kg), were selected. The study included farm visits, clinical inspection of pigs, completion of farm management questionnaires, pathological tests into the cause of the diarrhoea and analysis of the non-starch polysaccharide (NSP) content of feeds. The results from 17 farms designated as NSC and 10 control farms suggest dietary associations with NSC. Farms with NSC fed diets with significantly higher levels of NSPs, especially containing the sugars glucose, arabinose and xylose. Few management factors were identified, although the high prevalence of infectious colitis reduced the power of the study.     

Mutations in the juxtamembrane domain of c-KIT are associated with higher grade mast cell tumors in dogs

Mast cell tumors are among the most commonly seen tumors of the skin in dogs and are more highly aggressive than mast cell tumors of other species. Some breeds display a markedly higher incidence of mast cell tumor development than others and appear to have some genetic predisposition. Recently, mutations have been found in canine mast cell tumor tissues and cell lines within the juxtamembrane domain of the protooncogene c-KIT In previous studies utilizing a small number of cases, no association between the presence of a mutation and the breed of dog or grade of the tumor could be identified. An expanded study with a larger sample set was performed to explore this possibility. The juxtamembrane domain of c-KIT was amplified using the polymerase chain reaction from genomic DNA preparations of 88 paraffin-embedded mast cell tumors from selected breeds. Mutations, consisting of duplications and deletions, were found in 12 of the tumors. A significant association was found between the presence of a mutation and a higher grade of tumor but not between breed and grade or between breed and the presence of a mutation.