Localisation and activity of cathepsins K and B in equine osteoclasts

Cathepsin K and cathepsin B were immunolocalised in equine osteoclasts (OC s) present in ex vivo cartilage/subchondral bone samples. Samples were obtained post mortem from the lateral trochlear ridge (LTR) of six horses and ponies aged between 303 days gestation to 8 months. Strong expression of cathepsin K was detected in OC s, particularly those located at the osteochondral junction, apparently involved in the resorption of calcified cartilage. Cathepsin K expression was also detected in hypertrophic chondrocytes and in the endothelial cells of some blood vessels penetrating the hypertrophic zone of cartilage. By contrast, cathepsin B was either absent or present at very low levels in OC s.Osteoclast-like cells (OCL s) were generated in vitro from bone marrow (BM), obtained from the femurs of one horse and two ponies. High levels of cathepsin K activity but only very low levels of cathepsin B activity were demonstrated in OCL s using fluorogenic substrates for these enzymes. The cathepsin K activity could be blocked by the general cysteine proteinase inhibitor, E-64, but not by the cathepsin B inhibitor, CA-074Me. The cathepsin B activity was completely blocked by both CA-074Me and E-64. Taken together, these results suggest that cathepsin K is more important than cathepsin B in the osteoclastic resorption of bone and calcified cartilage of developing equine long bones. Given the apparent importance of cathepsin K in equine endochondral ossification further investigation into the possibility that abnormal expression of this enzyme is involved in the pathogenesis of equine developmental orthopaedic disease is warranted.     

Neutrophil Phagocytosis Following Inoculation of Salmonella choleraesuis into Swine

Neutrophils are an important mediator of host defence, especially in early stages of infection. A major function of neutrophils is the uptake and killing of invading microbes. Little is known about the effect of neutrophil activity on the pathogenesis and development of the carrier state in swine following infection with Salmonella choleraesuis. A human whole-blood microassay using flow cytometry was modified to measure the effect of S. choleraesuis infection in vivo on the rate of ingestion, or rate of uptake, of homologous bacteria by porcine neutrophils. Pigs were inoculated intranasally with 5–8×10⁸ CFU S. choleraesuis and blood was collected in heparinized tubes at –5, 0, 1, 2, 3 and 4 days post inoculation (PI). Heat-killed S. choleraesuis were labelled with fluorescein isothiocyanate and incubated for various times with diluted whole blood. Red blood cells were lysed, external non-phagocytized bacteria were quenched with a commercially available lysing solution, and fluorescence from internalized bacteria labelled with fluorescein isothiocyanate was detected by flow cytometry. The rate of uptake by neutrophils did not increase until 2 days PI and then remained elevated to 4 days PI. The minimal uptake of S. choleraesuis early after exposure to these organisms may provide an opportunity for the pathogen to colonize and/or replicate to levels that facilitate establishment of a carrier state or clinical infection in swine.     

Observations on a heard of beef cattle maintained in a tsetse area

Summary Three groups of Boran cattle were maintained under different trypanocidal drug regimes for 29 months in an area of “medium” tsetse challenge. The development of immunity to trypanosomiasis in the cattle was assessed on the basis of changes in trypanocidal drug requirement, development of parasitaemia, ability to maintain normal blood values, growth and response to challenge after the withdrawal of the drugs. Observations were also made on serum antibody content by immunofluorescence and on serum immunoglobulin levels. Cattle treated with Berenil on the development of clinical disease developed a partial immunity to trypanosomiasis after two years. Cattle treated as a group with Berenil on the development of patent parasitaemia in any one animal of the group did not develop immunity. Cattle treated as a group with Samorin using the same criterion for treatment developed a degree of immunity to the disease. It was concluded that group treatment with Samorin was the most suitable of the three regimes examined for the maintenance of beef cattle in a tsetse infested area.

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Resumen Se mantuvieron tres grupos de ganado Boran durante 29 meses bajo differentes regímenes terapéuticos en un área donde la concentración de moscas tsetse era mediana. Se llevó a cabo la evaluación del desarrollo de la inmunidad contra la tripanosomiasis teniendo como base los diferentes cambios en el requerimiento de drogas, desarrollo de parasitemia, abilidad para mantener los valores sanguíneos normales, crecimiento y respuestas a la descarga de parásitos después del retiro de la terápia. Se hicieron también observaciones del nivel de anticuerpos séricos por inmunofluorescencia y se determinó el nivel de inmunoglobulinas. Los animales tratados con Berenil cuando mostraban signos clínicos de la enfermedad, desarrollaron una inmunidad parcial a la tripanosomiasis después de dos a?os. Los animales tratados en grupo con Berenil cuando se detectó parasitemia en cualquier animal del grupo no desarrollaron inmunidad. El ganado tratado con Samorin en base de grupo siguiendo el mismo criterio para el tratamiento, desarrolló cierto grado de resistencia a la enfermedad. Se concluye que el tratamiento de grupo utilizando Samorin fue el mejor de los tres regímenes estudiados para el mantenimiento de ganado de carne en un área infestada de moscas tstse.

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Résumé Trois groupes de bovins Boran ont été maintenus vingt neuf mois, sous différents traitements trypanocides, dans une zone “moyennement” infestée de tsé-tsé. Le développement de l'immunité à la trypanosomiase a été évalué à partir des changements dans les besoins en trypanocides, du développement de la parasitémie, de l'aptitude à maintenir les valuers normales du sang, de la croissance et de la réaction à l'infection après la suppression des médicaments. Des observations ont aussi été faites sur la présence d'anticorps sériques par immunofluorescence et sur les teneurs en immunoglobines sériques. Le bétail traité au Berenil à l'apparition de signes cliniques a été partiellement immunisé au bout de deux ans. Dans le groupe du bétail traité au Berenil à l'apparition d'une parasitémie évidente, aucun animal n'a présenté d'immunité. Le groupe de bovins traité au Samorin, selon les nêmes critères a été bien immunisé.

     

Plasma aspartate aminotransferase and creatine kinaseactivities in thoroughbred racehorses in relation to age, sex, exercise and training

In order to investigate the effect of age, sex and month on the response of plasma aspartate aminotransferase(AST) and creatine kinase (CK) to exercise, blood samples were collected once a month between March and September from a group of 40 2- and 3-year-old (2yo and 3yo) thoroughbred racehorses (kept under the same managemental regimen) at rest before exercise (PRE) and at 2 (2H) and 24h (24H) post-exercise. The absolute change in activities between the 2H and PRE samples (2HΔ) and the 24H and PRE samples (24HΔ) was also calculated. Age had a significant effect on all measured and calculated parameters for colts (C), apart from 24HΔ CK but showed no effect in the fillies (F). Sex only had a significant effect in the 3yo in the 2HΔ CK. In the 2yo, significant effects of sex were found for both CK and AST in the PRE, 2H and 24H samples. The effect of month varied according to the classification group with only the 2yoC not showing any significant effect on any parameter. Fillies were, in general, more likely than colts to show greater than a twofold increase in CK activity at 2H post-exercise and the number of animals showing such an increase decreased as the season progressed. Very little change in AST activities occurred with exercise.     

Improved selection against the purple colour defect of cauliflower curds

Summary Purple colourations of the cauliflower curd detract from the commercial value of the crop. Curds were found to develop purple colourations when in aseptic nutrient culture, and this was correlated with their inherent tendencies to form purple curds in the field as revealed by a progeny test. It was advocated that selection against the defect in the field should be supported by assessment in culture.     

Selection against the bracting defect of cauliflower

Summary The appearance of bracts through the surface of the cauliflower curd had a heritability estimate of 0.73 ± 0.10 based on the regression of progeny on parent when grown under field conditions. When curds were taken from field grown plants and aseptically cultured, their bracting characteristics were enhanced. It is advocated that a two-tier system of selection, firstly in the field and then in culture, would increase the likelihood of breeding bract free cauliflowers.Also, Department of Biological Sciences, The Polytechnic, Hatfield, Hertfordshire, UK.     

Breeding system,taxonomy, and breeding strategy in cauliflower,Brassica oleracea var. botrytis L.)

Summary Cauliflowers representing those maturing in Britain in autumn, winter and spring were assessed for self-compatibility by self-pollen tube growth. A tendency existed for groups taking longer to mature to be more self-incompatible, but a range of incompatibilities was apparent in all groups. These results complement those of other workers.It is argued that despite demonstrable heterosis within many groups of cauliflowers, radical advances are probably best made by selecting self-compatible material from annual × biennial hybrid populations.     

Applying fire connectivity and centrality measures to mitigate the cheatgrass-fire cycle in the arid West,USA

Context

Strategic placement of fuel treatments across large landscapes is an important step to mitigate the collective effects of fires interacting over broad spatial and temporal extents. On landscapes where highly invasive cheatgrass (Bromus tectorum) is increasing fire activity, such an approach could help maintain landscape resilience.

Objectives

Our objectives are to 1) model and map fire connectivity on a cheatgrass-invaded landscape, as well as the centrality of large cheatgrass patches, in order to inform a landscape fuel treatment (i.e., a network of greenstrips); and 2) evaluate the modeled greenstrip network based on changes to cheatgrass patch centrality.

Methods

Our analysis covers 485-km² on the Kaibab National Forest in Northern Arizona. We apply a circuit-theoretic model of fire connectivity between all pairs of large cheatgrass patches. Based on these results, we calculate a measure of centrality for each patch to inform fuel treatment placement. We evaluate the modeled greenstrip network by comparing the pre- and post-treatment centrality of each patch.

Results

After modeling fire connectivity across the landscape, we identify 25 of 68 large cheatgrass patches with relatively high centrality. When we simulate greenstrips around these focal patches, model results suggest that they are effective in reducing the centrality for at least 19 of the 25 patches.

Conclusions

Fire connectivity models provide robust network centrality measures, which can help generate multiple, landscape fuel treatment alternatives and facilitate on-the-ground decisions. The extension of these methods is well suited for landscape fuels management in other vegetation communities and ecosystems.

     

Virus infections in cattle and sheep in Scotland 1975-1978

Over the four-year period 1975-78 attempts were made to identify virus in samples from 1231 outbreaks of disease in cattle, and 682 outbreaks of disease in sheep. A virus identification was possible in 26 per cent of these disease outbreaks. The nature and significance of these virus infections is discussed.