早熟禾不同品种根系分布及生物量分配对干旱胁迫的响应

为探讨早熟禾(Poa L.)不同品种根系生长状况、生物量分配与水分胁迫的关系,采用PVC管栽法,对布鲁克(Poa pratansis L. cv. Brooklawn)、英派克(Poa pratansis L. cv. Impact)和苏比纳(Poa supine Schrad. cv. SupraNova)3个品种进行干旱胁迫,测定了生物量、根冠比、根系密度、相对生长率等指标,分析了根、冠生物量分配及根系生长动态规律.结果表明:干旱胁迫对早熟禾3个品种的根、冠生物量累积和分配影响不同, 3个品种通过提高根干物质重量的分配策略来提高其抗旱能力的顺序依次是布鲁克、英派克、苏比纳;轻度水分胁迫有助于根系生长;3个品种相对生长率随着干旱胁迫程度的增加而降低,其中苏比纳降低最多;干旱条件下,土壤深层根系密度、根冠比增加的顺序依次为布鲁克、英派克、苏比纳.     

Phytomass estimation using eMODIS NDVI and ground data in arid rangelands of Morocco

The assessment of rangeland productivity in semi-extensively grazed arid rangelands is a prerequisite for livestock management in relation to sustainable use of pastoral resources. The objective of this study was to assess rangeland productivity based on normalised difference vegetation index (NDVI) images. Data on phytomass were measured on 61 field samples in arid rangelands of Morocco, covering various rangeland categories during autumn (November) and spring (April), i.e. when phytomass is at low and high levels, respectively, for two consecutive years (2008 and 2009). Dekadal EROS Moderate Resolution Imaging Spectroradiometer (eMODIS) NDVI data were linearly regressed to field measurements for these four periods. Results show that phytomass values were correlated with NDVI during spring, with R² and RMSE values of 0.82 and 0.3 t ha^?1, respectively. This study indicates there is a high potential for operational use of remotely sensed data to estimate rangeland phytomass of semi-extensively grazed rangelands.     

诱导多能干细胞技术在猪转基因研究中的应用前景

长期以来,猪都是科学研究中重要的生物模型,转基因猪在生物模型、器官移植和动物良种繁育等方面有着极其重要的研究及应用价值,而现在的转基因克隆猪的成功率及成活率都普遍偏低。诱导多能干细胞技术在再生医学和畜牧业等领域有着广泛而诱人的应用前景,但目前还较少被应用于转基因猪的研究中。作者对转基因技术和诱导多能干细胞技术的发展历程,特别是诱导多能干细胞技术在猪转基因研究中的应用进行简述,以期为开展相关研究的科研人员提供一定的参考。     

Development of a composite orthopaedic pain scale in horses

This study addresses development and validation of a composite multifactorial pain scale (CPS) in an experimental equine model of acute orthopaedic pain. Eighteen horses were allocated to control (sedation with/without epidural analgesia - mixture of morphine, ropivacaine, detomidine and ketamine) and experimental groups: amphotericin-B injection in the tarsocrural joint induced pain and analgesia was either i.v. phenylbutazone administered post-induction of synovitis, or pre-emptive epidural mixture, or a pre-emptive combination of the 2. Inter- and intra-observer reproducibility was good (0.8相似文献   

Genetic analyses of piglet survival and individual birth weight on first generation data of a selection experiment for piglet survival under outdoor conditions

Genetic parameters of piglet survival traits and birth weight were estimated on the first generation data of a selection experiment aimed at improving piglet survival using a multiple trait linear and threshold model. Data on 5293 piglets for survival at birth, at day one after birth and during the entire nursing period, as well as individual birth weight and litter size, were recorded in an outdoor production system. Genetic effects of piglet survival traits and birth weight were estimated based on threshold and Gaussian models, respectively, using a Bayesian approach. The statistical model included as fixed effects selection group, parity, gender, fostering, gestation length and month of farrowing and, alternatively, an adjustment for litter size. Direct genetic effects (i.e. the piglet's genetic potential) for piglet survival and birth weight were estimated separately, whereas maternal genetic and environmental effects could only be estimated for the given data structure in a combined litter effect. Posterior means of heritabilities for direct genetic effects of survival at birth, at first day after birth and the entire nursing period, as well as birth weight, were 0.08, 0.07, 0.08 and 0.20, respectively. Genetic correlations among survival traits were in the range of 0.29 to 0.40 and indicate that these traits were mainly attributable to different genetic effects. Genetic correlations between direct effects of survival traits and birth weight ranged between 0.18 and 0.23 and were reduced when weights of stillborn piglets were omitted in the analysis or the traits were adjusted for litter size. The magnitudes of direct genetic effects of survival traits are substantially higher than estimates in the literature, which may indicate that these traits have a higher genetic influence under outdoor conditions. The use of birth weight in the multiple trait estimation provided important information for the estimation of survival traits due to its favourable genetic correlations with survival, its high heritability and its high information content as a continuously measured trait.     

Ultra‐frequent HRAS p.Q61R somatic mutation in canine acanthomatous ameloblastoma reveals pathogenic similarities with human ameloblastoma

Ameloblastoma is a locally aggressive odontogenic tumour that occurs in humans and dogs. Most ameloblastomas (AM) in humans harbour mutually‐exclusive driving mutations in BRAF, HRAS, KRAS, NRAS or FGFR2 that activate MAPK signalling, and in SMO that activates Hedgehog signalling. The remarkable clinical and histological similarities between canine acanthomatous ameloblastoma (CAA) and AM suggest they may harbour similar driving mutations. In this study, aimed at characterizing the mutational status of SMO, BRAF, HRAS, KRAS, NRAS and FGFR2 in CAA, we used RNA sequencing, Sanger sequencing and restriction fragment length polymorphism assays to demonstrate that 94% of CAA (n = 16) harbour a somatic HRAS p.Q61R mutation. The similarities in MAPK‐activating mutational profiles between CAA and AM implicate conserved molecular mechanisms of tumorigenesis, thus, qualifying the dog as a potentially useful model of disease. Given the relevance of RAS mutations in the pathogenesis of odontogenic tumours and other types of cancer, the results of this study are of comparative, translational, and veterinary value.     

Type 2 diabetes mellitus with pancreatic β cell dysfunction in 3 horses confirmed with minimal model analysis

Reasons for performing study: Type 2 diabetes mellitus (T2DM) is diagnosed rarely in equine practice although it may be under‐recognised. A greater awareness of the condition and therapeutic considerations would be to the benefit of such cases presenting in practice. More investigation into the pharmacological management of these cases is needed. Objectives: Three cases of diabetes mellitus were investigated using a specific test for insulin sensitivity and pancreatic β cell function in order to define accurately and characterise the existence of T2DM in all 3 subjects. Methods: The insulin‐modified frequently sampled i.v. glucose tolerance test was performed in each case and the data so obtained were subject to minimal model analysis of insulin‐glucose dynamics. Cases were then monitored following treatment using a combination of dietary modification, metformin, glibenclamide and pergolide. Results: Marked insulin resistance was identified in each case and, furthermore, severe pancreatic β cell dysfunction was present therefore classifying each case as end stage T2DM. Treatment was nevertheless associated with restoration of normoglycaemia in all cases. Conclusions: T2DM in horses may be more common than generally considered. In some cases individuals may respond to therapy aimed at restoring insulin sensitivity and pancreatic function. Drugs used in other species for the treatment of T2DM have not yet been adequately tested in horses. Potential relevance: T2DM should be considered as an important differential diagnosis in mature to elderly horses and ponies suffering from weight loss, polydipsia and polyuria. Clinicians should be encouraged to offer treatment and management advice when such cases are encountered.     

《宠物外科手术学》教学模式改革与探讨

《宠物外科手术学》是一门实践性很强的学科,与其他专业相比,更强调能力的培养,强调实验技能和临床技能的训练,是宠物相关专业技能培养的重要组成部分。该课程对培养学生的临床思维能力、合理运用手术基本操作技术能力、学生对宠物外科手术技能综合运用能力、学生的社会就业方向等有着积极而重要的作用。为此,如何给学生更好地传授理论知识,提供更多临床实践和动手能力的机会,需要学校和教师在人才培养方面不断思索和改革。通过多年的临床教学经验,对该课程进行了一些教学改革尝试,旨在更好地培养学生宠物外科手术的实践能力,以适应社会的需要与发展。     

绵羊实验性硒过多症的研究Ⅰ.硒过多症动物模型的建立

对14只绵羊以0.1％亚硒酸钠液肌肉注射,逐渐增加剂量,历时3～4个月,复制出了慢性硒过多症动物模型。此动物模型是随着硒在体内的不断累积,呈现起病、中毒和致死三个不同的效应阶段,血硒水平在0.30、0.50、及1.00μg/ml以上,依次分别作为三个效应阶段的临界值。     

北京地区不同起源栓皮栎早期生长过程研究

栓皮栎(Quercus variabilis Blume)是我国分布最广的乔木树种和最重要的造林树种之一~([1]),栓皮栎林有显著地经济和生态效益~([2]).栓皮材质坚实耐用,纹理优美,强度较大、耐冲击,是船舶、家具、建筑、车辆、枕木、地板等用途的优良材源~([3]);同时栓皮铄根系发达,能够吸收多种有害的重金属元素,在保持山区水土、净化空气等方面发挥着不可估量的作用~([4]);另外,栓皮栎林为多种野生动物提供食物来源和栖息地~([5]).