Extending the viability of emu spermatozoa during in vitro storage by manipulation of temperature and diluent potassium concentration

1. Survival of emu spermatozoa during in vitro storage is not affected by increasing the extracellular [K⁺] to the point where it does not adversely affect spermatozoa function.

2. In three experiments, the effects were studied of [K⁺] in a diluent in the range 12·5–80?mM/l on emu spermatozoa survival for up to 48?h at 5, 10 or 20°C.

3. At the end of the storage period, spermatozoa viability, motility, fertilising ability and morphology were measured.

4. In Experiment 1, spermatozoa viability and morphology were adversely affected after storage (P?M/l [K⁺] whereas spermatozoa motility decreased as [K⁺] increased from 12·5 to 80?mM/l.

5. In Experiment 2, during storage at 5°C, the spermatozoa viability was comparable among any of the diluents (standard or modified) but morphology was better (P? 6. In Experiment 3, after 48?h of storage in a diluent containing 40?mM/l of [K⁺], the spermatozoa functions were better preserved at 10°C than at 5 or 20°C.

7. It is concluded that a higher than physiological level of potassium can be used in a diluent without detrimental effect on emu spermatozoa survival during 48?h storage and that the best outcome was with storage at 10°C rather than 5 or 20°C.     

Physiological and biochemical studies during flower development in two rose species

The present investigation was aimed to study the changes in various physio-chemical attributes in petals of two different rose species, Rosa damascena Mill and Rosa bourboniana Desport differing in flowering behaviour from small bud (stage 1) till full bloom (stage 8). In both rose species fresh weight, dry weight and moisture content were maximum during full bloom. Electrical conductivity of the petal diffusates reached maximum at full bloom with significantly higher values in R. damascena. In both the species, starch content declined as the flower reached its full bloom stage with maximum reducing sugar content during this period. With progressive increase in petal growth, total protein and RNA declined. The results showed that in both the species peroxidase (POX) and catalase (CAT) activity were lower during full bloom with high activity of invertase and lipoxygenase (LOX) at this period. The present study indicates that lipid peroxidation induced membrane permeability could partly be the result of higher lipoxygenase activity during full bloom. The possible significance of these findings is discussed in relation to flower development in the two diverse rose species.     

Characterization and purification of cytosolic and membrane-bound protease(s) in adults of Haemonchus contortus

The activity of protease(s) was observed separately in cytosolic and membrane-bound protease(s) from male and female Hae monchus contortus (Nematoda: Trichostrongylidae). Different fractions showed optimum protease activity at 37 degrees C, pH 8.5 and 8.0 mg casein concentration. The female fractions had a particularly high activity of protease(s) in comparison with the male fractions, especially of membrane-bound enzymes in the anterior half. Inhibition, activation studies revealed the presence of four kinds of protease(s) in cytosolic and membrane-bound fractions. Protease(s) in different fractions are purified to a greater extent by higher concentrations of saturated ammonium sulphate solution, i.e. ranging from 50 to 65%. The purification study revealed the presence of multiple forms of protease(s) in cytosolic and membrane-bound extracts of H. contortus.     

Identification of Chlamydia gallinacea in a parrot and in free‐range chickens in Australia

Chlamydia gallinacea is a recently described bacterial species in a genus known to infect and cause disease in animals and humans. Our report describes the identification of C. gallinacea infection in free‐range laying chickens (Gallus gallus) in Australia, and the identification of C. gallinacea infection in a parrot, a wild Australian galah (Eolophus roseicapillus). There is currently little knowledge of the effects of C. gallinacea infection on avian hosts, but it has been linked to respiratory disease in humans and could potentially cause similar disease in other species. Our report highlights the need for further study and surveillance of Chlamydia species in both wild and domestic hosts in Australia.     

Infectious dose‐dependent accumulation of live highly pathogenic avian influenza H5N1 virus in chicken skeletal muscle—implications for public health

Highly pathogenic avian influenza viruses (HPAIV) of H5N1 subtype are a major global threat to poultry and public health. Export of poultry products, such as chicken and duck meat, is a known source for the cross‐boundary spread of HPAI H5N1 viruses. Humans get infected with HPAI H5N1 viruses either by close contact with infected poultry or through consumption of fresh/undercooked poultry meat. Skeletal muscle is the largest soft tissue in chicken that has been shown to contain virus during systemic HPAIV infection and supports productive virus infection. However, the time between infection of a chicken with H5N1 virus and presence of virus in muscle tissue is not yet known. Further, it is also not clear whether chicken infected with low doses of H5N1 virus that cause non‐fatal subclinical infections continue to accumulate virus in skeletal muscle. We investigated the amount and duration of virus detection in skeletal muscle of chicken experimentally infected with different doses (10², 10³ and 10⁴ EID₅₀) of a HPAI H5N1 virus. Influenza viral antigen could be detected as early as 6 hr after infection and live virus was recovered from 48 hr after infection. Notably, chicken infected with lower levels of HPAI H5N1 virus (i.e., 10² EID₅₀) did not die acutely, but continued to accumulate high levels of H5N1 virus in skeletal muscle until 6 days post‐infection. Our data suggest that there is a potential risk of human exposure to H5N1 virus through meat from clinically healthy chicken infected with a low dose of virus. Our results highlight the need to implement rigorous monitoring systems to screen poultry meat from H5N1 endemic countries to limit the global spread of H5N1 viruses.     

Qualitative and quantitative ultrasound attributes of maternal‐foetal structures in pregnant ewes

The aim of this study was to examine foetal organs and placental tissue to establish a correlation between the changes in the composition of these structures associated with their maturation and the ultrasonographic characteristics of the images. Twenty‐four pregnant ewes were included in the study. Ultrasonography assessments were performed in B‐mode, from the ninth gestational week until parturition. The lungs, liver and kidneys of foetuses and placentomes were located in transverse and longitudinal sections to evaluate the echogenicity (hypoechoic, isoechoic, hyperechoic or mixed) and echotexture (homogeneous and heterogeneous) of the tissues of interest. For quantitative evaluation of the ultrasonographic characteristics, it was performed a computerized image analysis using a commercial software (Image ProPlus^®). Mean numerical pixel values (NPVs), pixel heterogeneity (standard deviation of NPVs) and minimum and maximum pixel values were measured by selecting five circular regions of interest in each assessed tissue. All evaluated tissues presented significant variations in the NPVs, except for the liver. Pulmonary NPVmean, NPVmin and NPVmax decreased gradually through gestational weeks. The renal parameters gradually decreased with the advancement of the gestational weeks until the 17th week and later stabilized. The placentome NPVmean, NPVmin and NPVmax decreased gradually over the course of weeks. The hepatic tissue did not show echogenicity and echotexture variations and presented medium echogenicity and homogeneous echotexture throughout the experimental period. It was concluded that pixels numerical evaluation of maternal‐foetal tissues was applicable and allowed the identification of quantitative ultrasonographic characteristics showing changes in echogenicity related to gestational age.     

Development and evaluation of a MAb based competitive-ELISA using helicase domain of NS3 protein for sero-diagnosis of bovine viral diarrhea in cattle and buffaloes

The aim of this study was to develop a competitive inhibition ELISA (CI-ELISA) for detection of antibodies to bovine viral diarrhea virus (BVDV) using the helicase domain of NS3 (non-structural) protein and monoclonal antibody (MAb) against it and to estimate its sensitivity and specificity using two commercial ELISA kits as independent references. The 45-kDa helicase domain of NS3 protein of BVDV was expressed in Escherichia coli and 18MAbs were developed against it. MAb-11G8 was selected for use in CI-ELISA on the basis of maximum inhibition (90%) obtained with BVDV type 1 infected calf serum. Based on the distribution of percent inhibition of known negative sera (n=166), a cut-off value was set at 40% inhibition. In testing 914 field serum samples of cattle (810) and buffaloes (104), the CI-ELISA showed a relative specificity of 95.75% and 97.38% and sensitivity of 96% and 94.43% with Ingenesa kit and Institut Pourquier kit, respectively. This study proved that the use of helicase domain of NS3 (45-kDa) is equally good as the whole NS3 protein (80-kDa) used in commercial kits for detection of BVDV antibodies in cattle and buffaloes.     

Toxoplasma gondii antibody in domestic cats in Melbourne

OBJECTIVES: To determine the prevalence of Toxoplasma gondii in a population of domestic cats in Melbourne. DESIGN: An ELISA assay was used to measure T gondii antibody titres in 103 cats from north-eastern Melbourne. Cats were obtained from outer suburban areas (less than 30 km from the Melbourne GPO) and from rural areas (more than 30 km from the Melbourne GPO). RESULTS: Thirty-nine percent of cats were positive for T gondii IgG. Older cats tended to have higher antibody titres. There was no significant difference in the T gondii antibody titres between males and females, or between cats living in urban areas and cats from rural areas. CONCLUSIONS: A significant proportion of cats from Melbourne have been exposed to Toxoplasma. This may have implications for the health of wildlife and humans.