The Functional Role of Oxytocin in the Induction of Oocyte Meiotic Resumption in Cattle

The aim of the present study was to examine the role of oxytocin (OT) in the progesterone (P4) and prostaglandins (PGs) pathway to induce oocyte meiotic resumption. Cumulus–oocyte complexes were co‐cultured with follicular hemisections for 15 h to determine the effects of different doses of OT or atosiban (ATO; oxytocin receptor antagonist) on oocyte meiotic resumption. In another experiment, we examined the effect of the interaction between P4, OT and PGs on the regulatory cascade of the oocyte meiotic resumption. Oxytocin at 1 μm was effective in inducing meiotic resumption in oocytes co‐cultured with follicular cells (84.0%), not differing from the positive control group (74.4%). Atosiban inhibited in a dose‐dependent manner the positive effect of OT on the meiotic resumption (27.6% metaphase I with 10 μm of ATO, which did not differ from the 25.5% of the negative control group). Furthermore, a third experiment showed that P4 was able to induce oocyte meiotic resumption, which was inhibited by ATO. However, the OT positive effect was not blocked by mifepristone (P4 antagonist), but was inhibited by indomethacin (a non‐selective PTGS2 inhibitor). Collectively, these data suggest a sequential role of P4, OT and PGs in the induction of oocyte meiotic resumption.     

动物疫苗及其合理使用（一）

疫苗接种是预防动物传染病发生的重要举措。依据免疫学理论,疫苗作为抗原,通过激发动物机体免疫系统,产生特异的体液免疫和细胞免疫,从而获得针对某种疾病的特异性免疫。疫苗一般分为细菌疫苗、病毒疫苗和类毒素疫苗等。用于防病治病的各种疫苗、菌苗又是特殊的生物药品,与普通化学药品具有完全不同的成分、功能和特性,疫苗中含有多种蛋白质（除细菌或病毒外,有的还含有保护剂、鸡胚尿囊液或细胞培养液）,它们均适合许多病原体的生长,有些制品还是活的微生物,一旦污染后果不堪设想。疫苗在保存、运输和使用时有其特别要求。如果方法不当,不但会使活性物质失活,起不到免疫防病作用;而且还可能适得其反,引发动物新的疾病,造成重大损失。     

Genetic diversity, presence of the syrB gene, host preference and virulence of Pseudomonas syringae pv. syringae strains from woody and herbaceous host plants

A total of 101 Pseudomonas syringae pv. syringae strains, obtained from international culture collections or isolated from diseased tissues of herbaceous and woody plant species, were assessed by repetitive PCR using the BOX primer, and for the presence of the syrB gene. Representative strains were also tested for pathogenicity to lilac, pear, peach, corn and bean, as well as for virulence to lemon and zucchini fruits. The unweighted pair-group method using arithmethic averages analysis (UPGMA) of genomic fingerprints revealed 17 different patterns which grouped into three major clusters, A, B and C. Most of the strains (52·4%) were included in patterns 1–4 of group A. These patterns comprised strains obtained from either herbaceous or woody species, and showed four fragments of similar mobility. Genetic variability was ascertained for strains isolated from apple, pear, apricot, Citrus spp. and cereals. No clear relationship was observed between host plant and bacterial genomic fingerprint. Variability was also observed in pathogenicity and virulence tests. The inoculation of pear leaves discriminated strains isolated from pear as well as the very aggressive strains, whereas inoculation of lilac, peach and corn did not discriminate the host plant from which the strains were originally isolated. Lemon fruit inoculation proved very effective for P. syringae pv. syringae virulence assessment. The syrB gene was present in almost all strains.     

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.     

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.     

D‐loop sequence mitochondrial DNA variability of Sarda goat and other goat breeds and populations reared in the Mediterranean area

To provide useful knowledge on goat breed origin and history, we studied the mitochondrial DNA (mtDNA) of 69 goats from five different breeds, Camosciata delle Alpi, Maltese, Nubian, Saanen and Sarda, and one population, the Tunisian. All goats analysed displayed a moderate haplotype and nucleotide diversity. The highest was in the Sarda – the autochthonous breed reared in Sardinia. On the basis of mtDNA control region sequences, animals showed a high genetic haplotype diversity, 35 haplotypes were each represented by a single sequence and only a few haplotypes were shared among the animals. New haplotypes of goats reared in the Mediterranean area were identified and the majority of Italian goats belonged to haplogroup A. This result confirmed worldwide distribution and diversity of haplogroup A.     

Using CERES-Wheat to simulate durum wheat production and phenology in Southern Sardinia,Italy

Durum wheat is a crop of great economic relevance for Mediterranean regions, especially in developing countries. A decreasing trend in durum production is expected in the near future because of several factors, in particular environmental constraints due to climate change and variability. The aim of this work was to test the predictive performance of CERES-Wheat model, implemented in DSSAT software systems, under Mediterranean climate condition and soil types of Southern Sardinia, Italy. CERES-Wheat model was calibrated for three durum wheat Italian varieties (Creso, Duilio, and Simeto) using a 30-year data set (1974–2004) and a trial and error iterative procedure. Then, the model was validated and evaluated using several statistics. The model showed a quite good performance in predicting grain yield and anthesis date, with errors comparable with those reported by other studies conducted on bread and durum wheat. Predictions of grain weight and grain number did not match very well observations, confirming the difficulties of CERES-Wheat in estimating grain yield components. The results of this study suggest the need of specific field experiments and further model evaluations and improvements to better understand model simulation results of grain yield components of durum wheat.     

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.