Microbiological evaluation of dressing procedures for crocodile carcases in Queensland

SUMMARY Microbiological testing of crocodiles during the dressing procedure has shown that sanitising the skin before skinning reduces the bacterial count on the skin and that dipping crocodile meat in 1.3% acetic acid solution effectively reduces bacterial levels. The total bacterial count on the processed meat sample was comparable with that obtained in the beef, pork and lamb industries. Salmonellae were isolated from 14 of the 72 carcases. Most (65%) of these isolates were in Salmonella subspecies III, formerly classified as Arizona.     

Programs for surveillance and monitoring of antibacterial residues in Australia, 1989 to 1993

SUMMARY The development of a State-based confirmatory testing capability for antibiotic residues in meat in Australia has allowed the rapid feedback to producers failing to comply with antibiotic maximum residue limits. The identification of problem areas in various categories of livestock, and subsequent focused surveillance programs, has reduced the prevalence of antibacterial residues in both domestic and export meat products. Failure to observe withholding periods of antibacterial drugs after treatment is the most significant cause of non-compliance. In the period July 1991 to June 1993 the compliance rate for antibacterial residues for all species was 99.9%.     

A screening test for subclinical liver disease in horses affected by pyrrolizidine alkaloid toxicosis

Objective: To evaluate various biochemical tests as indicators of subclinical liver disease in horses exposed to pyrrolizidine alkaloid toxicosis.
Design: A clinical pathology field study.
Animals: Twenty-two clinically normal horses from four properties in the Kimberley region of Western Australia.
Procedure: Serum samples from each horse were assayed for gamma glutamyltransferase, alkaline phosphatase and aspartate aminotransferase activities, and for serum bile acid concentration, albumin and total protein. Serum protein electrophoresis was performed and their amino acid profiles determined. Bromosulphophihalein halfclearance times were measured. Horses were then subjected to a single liver biopsy. Results were analysed by, variance of group means, the Fisher-Irwin exact test, and by sensitivity and specificity calculation.
Results: Horses were classified into 2 groups, of 10 unaffected and 12 subclinically affected, on the basis of liver histology. Significant differences between the unaffected and subclinical groups were observed for gamma glutamyltransferase and alkaline phosphatase activities (P < 0.01). Gamma glutamyltransferase had sufficient sensitivity (75%) and specificity (90%) to function as a primary screening test for subclinical liver disease in horses exposed to pyrrolizidine alkaloids. Alkaline phosphatase was useful, but with lower sensitivity (58%).
Conclusion: Serum gamma glutamyltransferase activity is a useful screening test for detecting subclinical liver disease in horses exposed to pyrrolizidine alkaloids under field conditions in northern Australia.     

Impact of dung from ivermectin-treated sheep on oogenesis and survival of adult Lucilia cuprina

Females of the Australian sheep blowfly, Lucilia cuprina, exploit sheep dung as a source of protein for egg development. Flies fed on dung collected from sheep 1 to 6 days after being drenched with the broad-spectrum antiparasitic drug ivermectin showed delayed reproductive development and reduced fecundity. Male and female survival was also reduced. Despite these effects, except where the recommended frequency of drenching (1 to 4 times per annum) is greatly exceeded, it is unlikely that ivermectin residues will affect any useful reduction in blowfly populations.     

Evolution of Iron Acquisition in Higher Plants

In the plant kingdom, two iron (Fe) acquisition strategies exist. All plant species, except grasses, acquire Fe^{2 +} from soil after reduction of Fe^{3 +} using the Strategy I mechanism. Although expressing many Strategy I activities, grasses employ the Strategy II mechanism, which involves the synthesis, secretion, and uptake of phytosiderophores that chelate Fe^{3 +} from soil. In recent years, several genes involved in Fe acquisition have been identified in plants. This study examined the phylogenetic distribution of iron-acquisition genes of five dicots, five grasses, and one gymnosperm. Both Strategy I and II plant species possessed either all or some genes for Strategy I. For Strategy II genes, only the five grasses expressed genes for phytosiderophore synthesis. Due to the conservation of Strategy I genes among both Strategy I and II species and absence of Strategy II genes from dicot and gymnosperm species, we concluded that Strategy II in grasses was derived relative to Strategy I.     

DIVERSITY AND IMPLICATIONS OF SOYBEAN STEM NITROGEN CONCENTRATION

Soybean [Glycine max (L.) Merr.] shoot nitrogen (N) traits are important for seed production and may hold potential for improving seed yield and quality. Field experiments were established to survey shoot N traits in i) plant introductions, ii) a recombinant inbred line (RIL) population, and iii) modern cultivars. A wide range of N concentrations was observed at beginning seed fill for leaves, petioles, and stems and at maturity for stems. Significant genotypic variations in stem N traits were found in modern cultivars and the RIL population. Molecular marker analysis identified multiple loci associated with stem N concentration. Significant relationships between various tissue N traits and seed yield and quality were also observed. These results illustrate the importance of N dynamics in vegetative tissues for soybean yield and seed composition. The observed variation in N traits indicates that selecting for vegetative N traits could potentially increase yield and improve seed quality.