In vitro propagation and germplasm cold-storage of fertile and male-sterile Allium trifoliatum subsp. hirsutum

Summary Procedures for in vitro clonal propagation and for cold-storage of propagules were developed for fertile and male-sterile genotypes of Allium trifoliatum subsp. hirsutum, var. hirsutum and var. sterile, respectively. Highest rate of shoot multiplication was achieved from basal leaf and umbel explants on a modified BDS medium supplemented with 9 mg/l benzyladenine. Naphthalene acetic acid reduced the propagation rate, and was not required for shoot multiplication. The resulting shoots were rooted in an indole butyric acid-supplemented medium, and bulbing occurred upon exposure to a 16 h photoperiod. The small dormant bulbs were transplanted into potting mixture and sprouted after termination of dormancy, resulting in phenotypically-normal plants. No significant differences, in either shoot regeneration or plant establishment, were found between fertile and male-sterile genotypes.Basal leaf explants of in vitro grown plantlets were stored at 4–6°C for up to 16 months. Standard medium, or modified media containing 0.4 to 10.0% sucrose or 1 to 10 mg/l paclobutrazol, were used in storage experiments. Eighty to 100% and 70% survival rates, were recorded after 8 and 16 months cold-storage, respectively, in a 10% sucrose medium. Following their transfer to standard culture conditions, these explants regenerated plants which were phenotypically similar to those developed in the potting mixture.Isozyme polymorphism of 13 proteins was used to assess the genetic stability of cold-stored explants. Considerable differences in zymograms were found between the fertile and the sterile varieties. However, no differences in isozyme profiles were detected between the control field-grown plants, and those which were established from in vitro-stored leaf base explants. The only exception were plantlets exposed to a high paclobutrazol concentration in storage. The latter exhibited a doubling in the alcohol dehydrogenase profile.Abbreviations ADH Alcohol dehydrogenase - BA benzyl adenine - IBPGR International Board for Plant Genetic Resources - MDH malate dehydrogenase - MS Murashige & Skoog medium - NAA naphthalene acetic acid     

Production and characterization of monoclonal antibodies to Actinobacillus pleuropneumoniae serotype 5b.

Monoclonal antibodies specific for capsular polysaccharide (CPS) and lipopolysaccharide (LPS) of A. pleuropneumoniae serotype 5b were generated by hybridoma cells and selected by indirect ELISA of culture supernatants with purified and structurally defined LPS and CPS preparations and their synthetic conjugates. It was shown in this study that at least one monoclonal antibody, 3B4, presented 100% specificity and recognized all A. pleuropneumoniae serotype 5 field strains tested in a dot-ELISA assay.     

A cross-sectional study to show Eperythrozoon ovis infection is prevalent in Western Australian sheep farms

A serological survey and risk factor study was conducted to estimate the prevalence of Eperythrozoon ovis infection in Western Australian weaner sheep, the prevalence of farms with infected sheep, and to identify factors affecting initiation and maintenance of infection on the farm. The study was conducted on 91 farms, purposively chosen from 41 randomly selected regional shires stratified by sheep number and rainfall zones. Twenty sheep were selected systematically from a mixed-sex flock on each farm and tested for serum antibody to E ovis using an enzyme-linked immunosorbent assay. Information on putative risk factors was collected using an interview questionnaire. Antibody to E ovis was detected in 4.5% of sheep on 47% of the farms sampled. The prevalence of E ovis infection in sheep was estimated at the 95% confidence level to be between 3.6 and 5.5%, and the prevalence of farms with infected sheep was estimated to be between 37.5 and 56.5%. Most farms with serological evidence of infection occurred in the Great Southern agricultural region (79.5%), south-east of Perth through to Albany (latitude 32 to 34 degrees S, longitude 116 to 120 degrees E), and in the Northern region (12.8%) surrounding Geraldton (latitude 29 degrees S, longitude 114 degrees E). There were significantly more farms (P less than 0.05) with evidence of infection in the Great Southern region compared to the Central region between Geraldton and Perth, and on farms in the region south compared to north of latitude 32 degrees S. None of the putative risk factors examined in the questionnaire were associated with serological evidence of infection on the farm.(ABSTRACT TRUNCATED AT 250 WORDS)     

Epidemiology of salmonellosis in the live sheep export industry

SUMMARY Salmonellosis in sheep was studied on 7 commercial voyages from Australia to the Middle East and in one animal house study. Faecal excretion of salmonellas was not a good indicator of pathological changes in the gastrointestinal tract. The ratio of the proportion of sheep excreting salmonellas to the proportion with histological lesions of salmonellosis ranged from 1:1 to 23:1. Increasing excretion rates in our studies indicated that most sheep would be exposed to infection, although deaths from salmonellosis were not spatially or temporally clustered as would be expected if challenge alone was a sufficient cause. We considered that inappetence predisposed to death from salmonellosis, and that sheep with inappetence were likely to be randomly distributed aboard ship. In the animal house study, histological lesions of salmonellosis were exclusively in inappetent sheep although almost all sheep excreted salmonellas in faeces. Lesions of salmonellosis were found only in sheep that were seriously ill or had died, which suggested that, under the conditions of lot-feeding and sea transport, most sheep with enteric lesions are likely to die. Lesions were not found in feeding controls. Adrenal gland weights, an indicator of stress duration and severity, were used to examine the temporal sequence of events in the development of salmonellosis. Weights were greater in sheep that died of inanition than in controls, suggesting that inappetent sheep were already stressed for that reason. The presence of enteric lesions of salmonellosis was associated with further increases in adrenal gland weights. In a small proportion of cases, septicaemic salmonellosis developed rapidly and without adrenal gland hypertrophy suggesting that the sheep succumbed before the adrenal glands had time to enlarge. We concluded that sheep were predisposed to salmonellosis by inappetence and that stress was involved in lesion development. We considered that the development of enteric lesions of salmonellosis, in the live export system, inevitably led to death.     

Feline immunodeficiency virus infection in a population of pet cats from southeastern Florida

Blood samples from 95 randomly selected pet cats that were brought to veterinarians in southeastern Florida were tested for antibodies to feline immunodeficiency virus (FIV). Virus-specific antibodies (indicative of virus infection) were found in 8 of the 95 (8.4%) cats tested. All of the virus-infected cats were males (statistically significant, P less than or equal to 0.016) and were at least 1 year of age. The 3 most severely ill cats infected with FIV were also infected with feline leukemia virus.     

Four cases of neoplasia in captive wild birds

Four cases of malignant neoplasia in captive wild birds are described: an adenocarcinoma of the adrenal gland in a Mountain duck (Tadorna tadornoides), a malignant melanoma in the thoracic cavity of a Combed duck (Sarkidiornis melanotos), a hepatocellular carcinoma with pulmonary metastasis in an Asian Purple Swamphen (Porphyrio porphyrio), and an undifferentiated carcinoma in the abdomen with metastasis to skeletal muscle in a White-Breasted Waterhen (Amaurornis phoenicurus). The tumors were diagnosed during a 1-year period and represented an incidence of neoplasia of 3.1%. These appear to be the first documented cases of a malignant adrenal gland tumor and a non-ocular melanoma in the order Anseriformes. The hepatocellular carcinoma failed to react with an immunoperoxidase stain for alphafetoprotein.     

Inherited progressive spinal myelinopathy in Murray Grey cattle

In a breeding experiment conducted to determine the mode of inheritance of progressive spinal myelinopathy, semen from a Murray Grey bull which had previously sired affected calves was used to inseminate 120 cows. Female progeny were then inseminated with semen from the same bull. Of the 51 calves born, six (11.8%) had spinal cord lesions consistent with progressive spinal myelinopathy. From analysis of pedigrees and the results of the breeding experiment it was concluded that the condition was inherited as an autosomal recessive condition in Murray Grey cattle.     

Respiratory and cardiac arrest under general anaesthesia: treatment by acupuncture of the nasal philtrum

The philtrum point VG 26 (Jen Chung) was needled in 69 cases of respiratory depression or apnoea in dogs and cats during induction or maintenance of general anaesthesia. Respiration was restored to normal or near normal rates within 10 to 30 seconds of insertion of the needle in all the cases. In seven cases of anaesthetic apnoea with concurrent cardiac arrest and absence of vital signs, the revival rate was 43 per cent. Those which recovered required four to 10 minutes of acupuncture stimulation. In eight cases of collapse due to other causes, the revival rate was 25 per cent. The cases included five sheep in shock following liver biopsy, two cases of haemorrhagic shock (dog, cat) and one terminal collapse in chronic congestive heart failure (dog).     

Tryptophan pyrrolase induced in human liver by hydrocortisone: effect on excretion of kynurenine

Administration of hydrocortisone causes two- to fourfold increase in the level of activity of tryptophan pyrrolase in human liver, as measured in needle-biopsy specimens. Correlation of the higher levels of the enzyme with the amounts of urinary kynurenine suggests that the tryptophan pyrrolase level, which is regulated by adrenocortical hormones, may be the important variable in the increased excretion of tryptophan metabolites that accompanies various diseases.