Vaccination of the brushtail possum (Trichosurus vulpecula) against Mycobacterium bovis infection with bacille Calmette-Guérin: the response to multiple doses.

In New Zealand, the brushtail possum (Trichosurus vulpecula) is the principal wildlife vector of bovine tuberculosis. Control of infected possum populations contributes to the control of tuberculosis in domestic livestock. Vaccination is potentially a complementary strategy to population control, but to be cost-effective, administration of the vaccine to possums would need to be from an appropriately designed automatic vaccinator. Possums themselves would activate the vaccinator so that it would deliver an aerosol spray of vaccine. There would be no direct way to prevent possums receiving multiple doses of vaccine. This study examined the effect on protective immunity of repeated vaccination. Captive possums were vaccinated with BCG strain pasteur 1173P2 either 12 times at weekly intervals, twice at 6-weekly intervals, or once. Vaccination was by a combination of intranasal aerosol and conjunctival instillation. Eight weeks after the last dose of vaccine, all possums were challenged intratracheally with Mycobacterium bovis strain 83/6235. Vaccination induced a significant immune response as measured by the lymphocyte proliferation assay (LPA). A significant level of protection, as measured by the response to challenge, developed in all the vaccinated possum groups, but protection was greatest in the group vaccinated 12 times. It was concluded that protection would be enhanced if vaccinations were repeated at short intervals (weekly), but no benefit or detriment resulted from revaccination after longer intervals (1-2 months).     

Bovine sire effects on daughters' in vitro blood neutrophil functions, lymphocyte blastogenesis, serum complement and conglutinin levels

Blood neutrophil functions, lymphocyte blastogenic responses, serum complement, and serum conglutinin activity of 98 lactating Holstein cows from two genetic lines were evaluated. The genetic lines were produced in a selection experiment that created and perpetuated genetic differences in milk production for up to seven generations. No significant differences between the two genetic lines of cows were found for neutrophil function, lymphocyte blastogenic responses, serum complement levels, or serum conglutinin levels. Significant differences between sire progeny groups within lines were found for unstimulated and mitogen-stimulated lymphocyte blastogenesis (P less than 0.0001), and almost all neutrophil functions (antibody independent neutrophil cytotoxicity, antibody dependent neutrophil cytotoxicity, ingestion of bacteria, iodination, chemiluminescence, chemokinesis, and chemotaxis (P less than or equal to 0.05)). Sire progeny group differences (P less than or equal to 0.0001) within lines for serum complement and conglutinin activity were also found. Neutrophil chemiluminescence activity (positive relationship; P less than or equal to 0.001), concanavalin A-stimulated lymphocyte blastogenesis (positive relationship; P less than or equal to 0.004), and serum conglutinin activity levels (negative relationship; P less than or equal to 0.01) each had small but significant associations with the total milk somatic cell count. Cows seropositive for bovine leukosis virus had increased resting and mitogen-stimulated lymphocyte blastogenic activity and were associated with increased in vitro neutrophil random migration and production of superoxide anion. Estimates of genetic parameters of various immune cell functions, of serum complement and of conglutinin levels for daughters of 11 sires with 4-6 daughters in the data set were determined. In this report, genetic variation was demonstrated for nonspecific humoral and cellular immunity.     

Characterisation of the 33kDa piroplasm surface antigen of Theileria orientalis/sergenti/buffeli isolates from West Java, Indonesia.

The immunodominant 33/35kDa antigen of a Theileria isolate from West Java, Indonesia, was characterised and immuno-affinity purified by use of a monoclonal antibody, KUL-a4, and was shown to be representative of the T. orientalis/sergenti/buffeli group. The aminoterminal sequence of the purified 35kDa peptide (20 residues) was determined by automated Edman degradation and found to correspond to the predicted amino acid sequence of a prospective p33 gene previously sequenced from the same isolate. The cleavage site of a putative signal peptide was identified and conforms the (-3, -1) rule for signal peptidases. The existence of dimeric and trimeric forms of the p33/35 antigen is hypothesised from Western blot profiles. KUL-a4 appeared specific for the T. orientalis/sergenti/buffeli group. It did not recognise in indirect fluorescence antibody test (IFAT), intraerythrocytic bodies of Anaplasma marginale or piroplasms and schizonts of T. mutans, T. parva and T. annulata, whereas cattle antisera raised to these species showed cross-reactivity in IFAT. It however, appeared weakly cross-reactive in Western blot and ELISA, with the 34kDa piroplasm antigen of one T. annulata (Gharb) isolate. The present study indicates that the isolated antigen belongs to the p33/34 antigen family described within the T. sergenti/orientalis/buffeli group, and documents the group-specificity of one of its epitopes.     

Cutaneous vascular neoplasia in 15 cats: clinical, morphologic, and immunohistochemical studies.

Seven cases of cutaneous hemangioma and nine of cutaneous hemangiosarcoma were diagnosed from biopsy specimens of 15 Domestic Shorthairs of 5,091 cats that were examined by necropsy or biopsy during the 5-year period from 1 January 1986 through 31 December 1990. All but three cats were male. Tumor cells of both hemangiomas and hemangiosarcomas were immunoreactive for factor VIII-related antigen and for vimentin by the avidin biotin peroxidase complex method. In cats with a median age of 10 years, hemangiomas occurred in skin with pigmented hair in six of seven cases without apparent site predilection. These solitary tumors did not recur after excision although one cat (No. 3) subsequently developed cutaneous hemangiosarcoma at another site. Seven of nine hemangiosarcomas occurred in dermis and subcutis of the head, usually on the pinna. All five hemangiosarcomas of the head, for which cutaneous pigmentation could be determined, occurred in unpigmented skin. Cats with hemangiosarcoma had a median age of 12.5 years at the time of diagnosis. Metastasis has not been documented, but hemangiosarcoma has recurred, from 1 month to 2 years after excision, in 6/7 cats that were studied.     

Histochemical studies on the dependence of secretory function of the major vestibular gland (Bartholin's gland) on ovarian steroid hormones in the cat.

The dependency of the secretory function of the feline major vestibular gland (Bartholin's gland) on the ovarian steroid hormones was studied histochemically. After estrogen (estradiol-17 beta or diethylstilbestrol), progesterone or a combination of these was administered to cats which were previously ovariohysterectomized, the major vestibular glands were removed, embedded in paraffin, sectioned, and stained by alcian blue, periodic acid-Schiff or peroxidase-labeled lectin (peanut agglutinin and wheat germ agglutinin). The vividly positive reactions to the stainings applied were observed in the secretory epithelial cells of the major vestibular glands in the estrogen treated animals. The dependency of the secretory function of the major vestibular glands on the estrogen was demonstrated in this study.     

Nitrogen retention and performance of brown laying hens on diets with different protein content and constant concentration of amino acids and energy.

1. The aim of this study was to determine the nitrogen balance and the performance of laying hens fed on diets with a protein content lower than the diets currently used in commercial practice but with adequate concentrations of lysine, sulphur amino acids, tryptophan and threonine. 2. Ninety-six Hy-Line Brown hens, 24 weeks old, were divided into 3 groups of 8 replicates and received, for 16 weeks, diets formulated to have 3 different protein concentrations: 170 (control), 150 and 130 g/kg CP and the same energy content. For each protein concentration, the contents of lysine, methionine, methionine+cystine, tryptophan and threonine were maintained at minimum requirement concentrations by supplying synthetic amino acids. 3. In the first half of the trial, egg production and egg weight were similar in all groups. From the 9th week onwards group 150 CP laid heavier eggs and had a slightly lower egg deposition and total mass. Food conversion ratio was best in the control group. 4. Nitrogen intake was related to the protein concentration of the diet, the food intake being almost the same in the 3 experimental groups. Faecal nitrogen content significantly and linearly decreased with reduction in dietary protein content and was about 50% of the intake. Considering the nitrogen faecal/intake ratio, the 150 CP group showed better nitrogen utilisation at each sampling time.     

Effect of Split Nitrogen Application on Growth and Yield of Wheat (T. aestivum L.) Genotypes with Different N-Assimilation Potential

A field experiment was conducted with different nitrogen regimes to assess the growth and yield performance of wheat genotypes which differ in nitrate assimilation potential. Genotypic differences in biomass accumulation were observed at different growth stages. The nitrogen treatment had little effect on biomass accumulation at early stages of growth, while at later stages of growth there was enhanced biomass accumulation when N was applied in more than two splits. On an average, genotypes with high nitrate reductase activity (the 'HNR' genotypes) accumulated 14.2 % more biomass than the genotypes with low nitrate reductase activity ('LNR' genotypes) when an extra dose (40 kg N ha⁻¹) of nitrogen was given at the time of anthesis. The application of nitrogen in more than two splits increased grain yield of both 'HNR' and 'LNR' genotypes mainly by increasing grain weight per ear. The application of an extra dose of nitrogen (40 kg N ha⁻¹) at the time of anthesis increased grain yield of 'HNR' genotypes by 38.5 % as compared to 'LNR' genotypes.