奶牛分子育种专题学习网站的建设构想

阐述了建设奶牛分子育种专题学习网站的意义和构想,规划了网站的主要内容和发展方向,为相关专业的研究者和从业人员提供参考。     

TMV和PVY外壳蛋白双基因融合干涉及烟草转化

为了降低烟草花叶病毒（tobacco mosaic virus,TMV）和马铃薯Y病毒（potato irus Y,PVY）复合侵染对烟草带来的危害,本实验找到TMV—CP和PVY—CP基因部分保守序列,将保守序列进行双基因融合,此双基因即为RNAi的靶序列,用限制性内切酶将双基因从pMD18-T载体上切下,正反向连接到pUCCRNAi载体后,经酶切鉴定后定向连接到含超强启动子的pC2300—35S—OCS表达载体上,利用冻融法将此表达载体导入只含辅助质粒的根癌农杆菌中,构建含靶序列反向重复结构的RNAi双元载体系统,提取转化质粒,经酶切验证鉴定表明TMV和PVY外壳蛋白基因植物表达双元载体构建成功。并转化烟草,获得了3株对TMV和PVY抗性显著提高的转基因烟草。     

腐殖酸和柠檬酸对人工合成磷源释磷效应的比较

采用实验室合成和实验室模拟的方法,研究了高分子腐殖酸和低分子柠檬酸,在不同固液比、不同浓度条件下对几种人工合成磷源的释磷效应.结果表明,两种有机酸对人工合成磷酸盐中磷素的活化与有机酸的种类、浓度、固液比和磷酸盐的种类有关.供试的两种有机酸(腐殖酸、柠檬酸)均能不同程度地促进不同合成磷源(磷酸二钙、磷酸八钙、氟磷灰石、铁磷、铝磷)中磷素的释放,释磷量最高可达2490 mg·kg<'-1>;有机酸对合成磷酸盐中磷素的活化随着有机酸浓度的增加而增加,而固液比变化时,各合成磷源的活化情况无固定趋势;在相同条件下(短时间内),低分子的柠檬酸对合成磷酸盐中磷素的活化能力强于高分子的腐殖酸,且柠檬酸作用下的释磷量可以达到腐殖酸的3倍以上. 应.结果表明,两种有机酸对人工合成磷酸盐中磷素的活化与有机酸的种类、浓度、固液比和磷酸盐的种类有关.供试的两种有机酸(腐殖酸、柠檬酸)均能不同程度地促进不同合成磷源(磷酸二钙、磷酸八钙、氟磷灰石、铁磷、铝磷)中磷素的释放,释磷量最高可达2490 mg·kg-1;有机酸对合成磷酸盐中磷素的活化随着有机酸浓度的增加而增加,而固液比变化时,各合成磷源的活化情况无固定趋势;在相同条件下(短 间内),低分子的柠檬酸对合成磷酸盐中磷素的活化能力强于高分子的腐殖酸,且柠檬酸作用下的释磷量可以达到腐殖酸的3倍以上. 应.结果表明,两种有机酸对人工合成磷酸盐中磷素的活     

基于全卷积网络的哺乳母猪图像分割

猪舍场景下,光照变化、母猪体表颜色不均及与环境颜色对比度不大、母猪与仔猪的粘连等,均给目标分割带来很大的困难。该文提出了基于全卷积网络(FCN,fully convolutional networks)的哺乳母猪图像分割算法。以VGG16为基础网络,采用融合深层抽象特征与浅层细节特征并将融合的特征图上采样8倍的跳跃式结构,设计哺乳母猪分割的FCN。利用Caffe深度学习框架,以7栏伴有不同日龄仔猪的3811幅哺乳母猪训练样本进行母猪分割FCN训练,在另外21栏的523幅哺乳母猪测试集上的分割结果表明:该算法可有效避免光线变化、母猪颜色不均、小猪遮挡与粘连等影响,实现完整的哺乳母猪区域分割;分割的平均准确率达到99.28%,平均区域重合度达到95.16%,平均速度达到0.22 s/幅。与深度卷积网络的SDS(simultaneous detection and segmentation)及传统的基于图论的图像分割、基于水平集的图像分割方法做了对比试验,该文分割方法平均区域重合度分别比这3种方法高出9.99、31.96和26.44个百分点,有较好的泛化性和鲁棒性,实现了猪舍场景下哺乳母猪准确、快速分割,可为猪只图像分割提供了技术参考。     

Demographic factors associated with the diet quality of older US men: baseline data from the Osteoporotic Fractures in Men (MrOS) study

OBJECTIVE: Throughout the world, the proportion of the male population aged 65 years and older is increasing. Yet, we have limited information regarding diet quality and predictors of diet quality in this segment of the population. The objectives of the current analyses are to describe the diet quality of a cohort of men >65 years of age, and identify lifestyle factors associated with poor diet quality. METHODS: We present a cross-sectional analysis of the diet quality of 5928 men, aged 65-100 years, who are participants in the Osteoporotic Fractures in Men (MrOS) cohort study. Dietary intake was determined using a modified Block 98 food-frequency questionnaire. Diet quality was calculated using the previously validated Diet Quality Index-Revised (DQI-R). Univariate and multivariate modelling was used to estimate the variance in diet quality predicted by a number of sociodemographic factors, including age, race/ethnicity, body mass index (BMI), marital status, education, smoking status, physical activity, self-perceived health and nutritional supplement use. RESULTS: Overall, we found that in this geographically diverse group of older men, diet quality was low, with a mean modified DQI-R for the entire study population of 62.5 (standard deviation 13.1) out of an ideal of 100. Further, younger age, very low total calorie intake (< or = 1187 kcal day- 1), higher BMI, residence in a North or Southeast community, being of African-American or Hispanic race, being less educated, not using dietary supplements and smoking were each significant independent predictors of a poorer diet. CONCLUSION: These data may prove useful in both understanding the dietary intake of older US men as it relates to published dietary guidelines, and for targeting future dietary intervention programmes.     

An evaluation of the precision,and various sources of error,in daily and cumulative precipitation chemistry sampling

Experiments have been carried out to assess the precision and various potential sources of error in precipitation chemistry and deposition measurements made by the Acidic Precipitation in Ontario Study (APIOS). It was found that reproducibility of daily precipitation concentration measurements of S0₄ ^? and NO₃ ^? using colocated Aerochem Metrics samplers is 96% or better for 50% of the time, and 73% or better for 95 % of the time. For these parameters, MIC Type A 28-d samplers give reproducibilities of 94% or better 50% of the time, and 79% or better 95 % of the time. The reproducibility for the concentration of the other major ions, and loading (concentration times sample depth) is somewhat poorer. Concentration changes due to sample degradation or evaporative losses under field conditions are negligible or small on average, even for 28-d samples. For 28-d concentration measurements using MIC Type A collectors, errors due to evaporation amount to about 3% as an annual average, and 5% during the summer period. For S0₄ ^? and NO₃ ^?, overall long-term errors due to exposure under field conditions (including dry contamination and degradation due to chemical reactions), and sample handling, are less than 10%, at least for the techniques used in APIOS. A major potential source of error still to be quantified is unrepresentative sampling by automatic wet-only collectros (i.e., missing of initial portions of precipitation events due to sluggish sensor response, or less than 100% collection efficiencies of precipitation amounts).     

Concentration and deposition of trace metals in Ontario-1982

Results of trace metal concentrations in air and precipitation and the corresponding wet and dry deposition in Ontario in 1982 arc reported. In terms of the spatial patterns, in general, there was a decreasing gradient from south-to-north in both concentration and deposition. Patterns differed with each parameter although certain groups of metals (e.g., Fe and Al; Pb, Zn, and Mn) displayed similar patterns. In general, wet deposition was greater than dry deposition at all sites. Geographically, the variability in the wet to dry deposition ratio for coarse particles (MMD > 2.5 μm) was small. However, it increased from the south to the north for fine particles (MMD < 2.5 μm), being higher away from the source areas. Scavenging ratios (W) have been derived from the precipitation and air concentrations of trace metals. The scatter in W is quite large for all trace metals, up to 2 orders of magnitude. There was little seasonal variability in W for fine particles (Pb, Mn, Zn, and Cd). However, coarse particles (Fe, Al, and Cu) were more efficiently scavenged by snow than by rain.     

A quality assurance program and quality assessment of the acidic precipitation in Ontario study (APIOS) deposition monitoring networks

Kinetics of H+ consumption by mineral dissolution in a surface soil and a subsoil of an acid woodland soil were studied by means of batch type experiments and stationary pH titrations. Mineral dissolution in the subsoil could effectively be described by congruent dissolution of illite (K_0.6Mg_0.25A1_2.3S1₃0₁₀(OH)₂) followed by an incongruent dissolution stage. In the incongruent stage the concentration of Al decreased while concentrations of K and Mg continued to increase. Congruent dissolution rates of illite could be predicted with power type relationships from transition state theory. In the incongruent dissolution stage the activities of H and Al appeared to be controlled by precipitation of A1(OH)₃. Results of this kind of experiments could be helpful to understand the behavior of Al and base cations in acid soils and soils with high atmospheric loadings of acid. Comparison of the results of batch experiments for a surface soil and a subsoil showed that initially proton consumption in the surface soil is faster and more effective due to the presence of a relatively high cation exchange capacity and base saturation value. However with progressive proton consumption and increasing reaction times proton consumption in the subsoil becomes faster than in the surface soil, presumably due to higher rates of mineral dissolution in the subsoil. Lower dissolution rates in the surface soil may result from lower contents of easily weatherable minerals, due to excessive leaching in the past which is reflected in a 17% lower acid neutralizing capacity than in the subsoil.     

再生丝素膜的生物安全性评估试验

以再生丝素蛋白为原料,采用旋转干燥法,通过控制温度和湿度及乙醇改性,最终得到不溶于水的丝素膜。为了评价再生丝素膜的生物安全性,进行体外细胞毒性、全身过敏反应、迟发型超敏反应、急性毒性反应、热原反应以及溶血性试验。结果：用丝素膜浸提液对体外培养的成纤维细胞进行处理后,细胞平均相对增殖率为92.3%,属于细胞毒性I级。小鼠经由100%丝素膜浸提液多次致敏后再次激发,未产生全身性过敏反应;供试小鼠静脉大剂量注射100%丝素膜浸提液后全部存活,无急性全身毒性反应,7d观察期内小鼠的体质量逐步增长;用100%丝素膜浸提液对家兔进行静脉注射后,兔的单只体温升高幅度为0.2～0.5 ℃,未超0.6 ℃上限,总和也未超1.4 ℃上限;选取不同剂量（100%、50%、25%、10%）丝素膜浸提液对家兔进行溶血试验,溶血率为4.02%、2.57%、1.56%、1.01%,均小于5%。综上所述,本研究制备的再生丝素膜状材料,具有良好的生物安全性。     

13个药用石斛种质生物学特性比较研究

旨在减少药用石斛产业化发展中对野生中药材资源的依赖,筛选适合人工栽培的优良种质,实现中药产业持续发展与生态环境保护相协调。以湖北英山引种收集的13个药用石斛原生种质为试材,采用物候期观测、茎叶形态和花形态等生物学特性观测方法,同时进行生长适应性比较。结果表明：不同药用石斛种质的物候期不同,花期最早在3月底,多数集中在4—5月,最晚可到7—8月。不同种质间茎叶形态和花形态存在显著差异,可分为高大型、普通型和小型3个类型。不同药用石斛种质的花瓣和唇瓣颜色主要在白色到黄绿色之间变化。花瓣质地以革质为主,少数为厚革质、纸质或膜质。‘霍山石斛’、‘铁皮石斛’、‘铜皮石斛’和‘罗河石斛’的生长适应性较好。湖北省英山县地理气候条件优越,适合大多数药用石斛的生长。物候期、茎叶形态和花形态是区分药用石斛种质类别的重要指标。‘霍山石斛’、‘铁皮石斛’、‘铜皮石斛’（江西种源）是可以在湖北省推广发展的优质种质。