Progressive ataxia associated with degenerative thoracic myelopathy in Merino sheep

A neurological disorder in Merino sheep, characterised clinically by progressive posterior ataxia and microscopically by Wallerian degeneration in thoracic segments of the spinal cord, is described. Animals of both sexes were affected, with the earliest onset of disease being at 5 months of age. Most affected animals died before 2 years of age. The clinical, pathological and epidemiological features suggest that this degenerative thoracic myelopathy is a previously unrecognised entity differing from other reported causes of ataxia in sheep in Australia.     

关于加强对肉鸡非典型新城疫和低致病性禽流感防治的建议

随着对鸡传染病防制技术水平的提高和相应的高科技产品的推广运用,加上政府和广大养鸡场（户）对典型新城疫（ND）和高致病性禽流感（HPAIH5亚型）防制工作的重视,成功地控制了这两种疾病的发生。但当前肉鸡业最易忽视、危害又最大的却是非典型新城疫（CND）和低致病力H9亚型禽流感（LPAI）。所谓“重视”是大家都接种了AI和ND疫苗,而忽视的是对AI只接种H5亚型而未接种H9亚型禽流感疫苗;     

Soil microbial biomass: The eco-physiological approach

In the 1980s ecosystem research projects were implemented world-wide since there was a pressing need to quantify the impacts of anthropogenic pollutants. Soil ecosystem analyses concentrated first on the quantification of the element and energy transfer between pools. Since mineralization of organic substrates and the release of nutrients and elements are due to the heterotrophic activity of the microbial decomposer compartment, this subsystem of terrestrial ecosystems gained importance. Direct microscopic observation methods were inadequate for the quantification of environmental impacts on the microflora. We adopted the maintenance requirement concept for the quantification of environmental impacts or stress effects on the soil microbial community. The paper gives a brief inside to the concept of maintenance from autecological studies and describes the underlying points which lead to our experimental approach of its application at the synecological level (i.e., microbial biomass as a single ecological entity) - a process which rested on long-term continuous research.     

Decomposition of 14C- and 15N-labelled microbial cells in soil

To obtain detailed information on the quantities and characteristics of nitrogen derived from mineralizing dead microbial biomass in soil, ¹⁴C- and ¹⁵N-labelled microorganisms, i.e. three eukaryotic (fungal) species, two prokaryotic species or their mixture (eukaryotic to prokaryotic cells = 8:2), were grown in vitro, dried, ground and added to parabrown earth and chernozem soils, respectively. The mean percent of ¹⁴C decomposition of labelled microorganisms obtained after 10 days was 43 ± 6.3% for parabrown earth and 34 ± 4.0% for chernozem soil. About 50% of the C in the dead microorganisms was mineralized during the first 28 days of incubation. About 76% of the flush of soil organic N mineralization within 28 days, which was caused by the drying-rewetting treatment, was derived from dead microbial biomass in soil. About 33% of the added dead microbial-¹⁵N was mineralized in parabrown earth soil during 28 days of incubation and about 37% of newly immobilized ¹⁵N during the decomposition of added microorganisms was mineralized during the 28 days following a dryingrewetting treatment.     

Mineralization of nutrients from soil microbial biomass

Soil samples of parabrown earth and chernozem, each having a different amount of microbial biomass, were used to investigate the contribution of microbial cells to the pool of mobile plant nutrients in soils. The quantities of nutrients mobilized in soils which had been dried or fumigated were closely related to the quantities available in freshly-killed biomass. For the percent of N mineralized from dead microbial biomass in arable soil during 28 days, a “k_N-factor” (28 days) of 0.37 was suggested. In oven-dried (70°C) and air-dried (room temperature) soils, approximately 77 and 55% of the N mineralized after remoistening and incubating at 22°C for 4 weeks came from the freshly-killed biomass. The remaining 23 and 45% were derived from non-biomass organic N fractions of the soils. In fumigation experiments (CHCl₃, 24 h), the amount of P released was closely related to the P content of the soil microbial biomass. The fluctuating amounts of K available after fumigation did not correspond to the amount of biomass killed. A scheme for the transformation of dead microbial biomass-C and -N in arable soil is suggested.     

Identification of the DDAH2 Protein in Pig Reproductive Tract Mucus: A Putative Oestrus Detection Marker

Precisely detecting oestrus is important for artificial insemination. The aims of this study were to identify oestrus‐specific sow mucus proteins to determine the optimal time for artificial insemination. The proestrous‐ and oestrous‐stage mucus proteins were purified and analysed with proteomic tools such as two‐dimensional gel electrophoresis and matrix‐assisted laser desorption/ionization–time‐of‐flight analyses. Among the differentially expressed proteins, the dimethylarginine dimethylaminohydrolase 2 (DDAH2) protein showed a 3.6‐fold increase during the proestrous stage compared to that during the oestrous stage. A western immunoblot study revealed that two of three sow mucus samples clearly showed negative anti‐DDAH2 antibody activity during the oestrous stage. This study demonstrated that the pig DDAH2 mucus protein exists during the proestrous stage, but not during the oestrous stage, suggesting that mucus DDAH2 could be useful as an oestrus detection marker.     

糖源对棉花花药培养的影响──Ⅰ 糖源对棉花花药愈伤组织诱导的影响

糖源在棉花花药培养中起着重要作用,不同糖源所起的作用不同。可溶性淀粉、蔗糖和葡萄糖有利于棉花花药愈伤组织的诱导和生长;麦芽糖对花药愈伤组织的诱导和生长促进作用不大;乳糖不利于愈伤组织的诱导。甘露醇的添加抑制了愈伤组织的诱导和生长。不同糖浓度对棉花花药愈伤组织诱导和生长的影响也不同,一般低浓度糖易诱导形成愈伤组织和愈伤组织的快速增殖。蔗糖的最佳使用浓度为３０ｇ／Ｌ。在不含糖源的培养基上棉花花药不能诱导形成愈伤组织,继代培养的愈伤组织也不易生长。培养条件和基因型也影响着糖源的使用效果。当以淀粉为糖源时,其具有胞外水解作用。