油脂在提高公猪生产力和生育力上的潜在作用

精子及其相关精浆中所含的脂肪成分在组成和脂肪酸成分上是非常独特的。长链多不饱和脂肪酸 (即具有 2 0或 2 2个碳原子并含三个以上双键的脂肪酸 )在绝大多数主要组织所含脂肪中的含量非常有限 ,但在精子和精浆中的含量相当高 ,并具有明显的种属特异性。油脂的这种特性现在日益被认为是使受精最终成功所特别需要的。本综述根据最近一的些研究结果撰写而成 ,从精液质量和功能的一系列决定因子的角度论述了使现代种公猪精子中脂肪 /脂肪酸参数最佳化的可能性 ,可见人们对一系列参数所作的一系列重要研究 ,产生了使公猪和母猪的繁殖能力都得到提高的高度有益结果。文章还从主要的营养学特性和化学特性方面对研究结果进行了讨论 ,并与其它家畜进行了比较 ,还讨论了其对猪繁育部门可能的商业应用价值。     

Breed-related expression patterns of Ki67, γH2AX,and p21 during ageing in the canine liver

Veterinary Research Communications - Cellular senescence is a molecular hallmark of ageing that is associated with multiple pathologies, and DNA damage marker γH2AX, together with cell cycle...     

Starving the soil of plant inputs for 50 years reduces abundance but not diversity of soil bacterial communities

If soil communities rely on plant-derived carbon, is biodiversity lost when this primary source is removed? Soil microbial and mesofaunal communities at the Rothamsted Highfield site were compared under a mixed grass sward, arable rotation and a section maintained as a bare-fallow for the past 50 years by regular tillage. Organic matter reserves have been degraded and microbial and mesofaunal numbers and mite diversity have declined in this unique bare-fallow site, where fresh carbon inputs have been drastically reduced. However, it supports a species-rich metabolically active bacterial community of similar diversity to that in soil maintained as grass sward. Thus in contrast to soil mesofauna, bacterial diversity (but not abundance) is apparently independent of plant inputs.     

Explaining urban governance in the midst of political transformation: The city of Macao

This paper takes a close look at the urban governance and political culture of Macao, the world largest casino city. Macao has experienced spectacular economic growth since gaming liberalisation in 2002 and China's Free Individual Travel scheme launched in 2003. However, the booming gaming sector has crowded out other sectors of Macao. It has not only made the city's economy mono‐structured and consequently extremely vulnerable to external shocks and fluctuations but also induced serious social divisions and political controversies within the local community. By tracing the root cause of the ongoing dilemma and crisis in the mode of governance, the dynamic relationships between formal and informal institutions, consensus politics and the social group culture are intensively discussed in a historical context. In fact, the sustainable development of the former Portuguese colony has largely been hindered by its residents' passive attitudes toward political communication, non‐transparent urban governance, the absence of a middle class and the dominance of pro‐establishment social groups.     

Survival of bacterial DNA and culturable bacteria in archived soils from the Rothamsted Broadbalk experiment

Dried soil samples from many sources have been stored in archives world-wide over the years, but there has been little research on their value for studying microbial populations. Samples collected since 1843 from the Broadbalk field experiment on crop nutrition at Rothamsted have been used to document changes in the structure and composition of soils as agricultural practices evolve, also offering an invaluable record of environmental changes from the pre- to post-industrial era in the UK. To date, the microbial communities of these soils have not been studied, in part due to the well-documented drop in bacterial culturability in dried soils. However, modern molecular methods based on PCR amplification of DNA extracted directly from soil do not require bacterial cells to be viable or intact and may allow investigations into the legacy of bacteria that were present at the time of sample collection.

In a preliminary study, to establish if dried soils can provide a historical record of bacterial communities, samples from the Broadbalk soil archive dating back to 1868 were investigated and plots treated with either farmyard manure (FYM) or inorganic fertilizer (NPK) were compared. As anticipated, the processes of air-drying and milling greatly reduced bacterial viability whilst DNA yields declined less and may be preserved by desiccation. A higher proportion of culturable bacteria survived the archiving process in the FYM soil, possibly protected by the increased soil organic matter. The majority of surviving bacteria were firmicutes, whether collected in 2003 or in 1914, but a wide range of genera was detected in DNA extracted from the samples using PCR and DGGE of 16S rRNA genes. Analysis of DGGE band profiles indicated that the two plots maintained divergent populations. Sequence analysis of bands excised from DGGE gels, from a sample collected in 1914, revealed DNA from - and β-proteobacteria as well as firmicutes. PCR using primers specific for ammonia oxidizing bacteria showed similar band profiles across the two treatments in recently collected samples, however older samples from the NPK plot showed greater divergence. Primers specific for the genus Pseudomonas were designed and used in real-time quantitative PCR to indicate that archived soil collected in 1868 contained 10-fold less pseudomonad DNA than fresh soil, representing around 10⁵ genomes g⁻¹ soil. Prior to milling, dramatically less pseudomonad DNA was extracted from recently collected air-dried soil from the NPK compared to the FYM plot; otherwise, the two plots followed similar trends. Overall bacterial abundance, diversity and survival during the archiving process differed in the two soils, possibly due to differences in clay and soil organic matter content. Nevertheless, the results demonstrate that air-dried soils can protect microbial DNA for more than 150 years and offer an invaluable resource for future research.