Changes in daily energy amounts of main milk components (lactose, protein and fat) during the lactation of high-yielding dairy cows

The aim of this study was to examine the changes of the daily energy amount of lactose, protein and fat throughout the lactations, and compare them to each other. A total of 309 Israeli Holstein-Friesian cows from one kibbutz were investigated in three lactations, and information was given for a period of five years from 1996 to the end of 2000. The distribution of milk components and milk yield during lactation, and changes of the absolute and relative energy amount in the different milk components were calculated and evaluated. The results showed changes in the energy content of milk and its different components throughout the lactation. Each component (fat, lactose and protein) is dominant in different periods during the lactation. The energy amount from fat reaches a peak first, between days 40 and 50. Lactose has a peak at about day 66 of lactation, and protein reaches the peak last, approximately at day 104 of lactation. It seems that this peak sequence is constant and it is considered to be physiological. It might be suggested that there is a regulation governing the secretion of the different components at different times, and only one component is dominant in a given period. Each component exerts negative and positive influences on the secretion of the other components, which interact with each other and are not fully independent.     

油菜素内酯代谢相关基因BAS1等位变异影响小麦籽粒密度及粒重表型

BAS1(phy B activation-tagged suppressor1)是调控油菜素内酯活性的关键基因。本研究利用由和尚麦和豫麦8679杂交后代构建的RIL群体(包括129个家系),研究了BAS1和小麦千粒重、籽粒密度两个产量性状的关系。结果表明BAS1基因位点等位变异对千粒重和籽粒密度具有显著的影响,B型等位基因的家系其千粒重和籽粒密度均值均显著高于A型等位基因的家系。相关分析表明,BAS1位点等位变异分别与千粒重和籽粒密度呈显著(0.178*)和极显著(0.327***)正相关。研究结果揭示了BAS1基因位点等位变异与小麦粒重、籽粒密度间的密切联系,这对解释小麦产量形成机制及其指导高产育种具有重要的意义。     

盐胁迫下棉花叶片差异蛋白表达的分析

以耐盐的陆地棉品种中07为研究材料,在其生长的三叶期,用未处理和0.4%NaCl胁迫处理24h的幼苗,分别提取其叶片全蛋白。通过等电聚焦和第二向SDS-PAGE技术获得完整的棉花叶片总蛋白图,利用ImageMaste-2DElite5.0软件分析各个差异蛋白在对照和0.4%NaCl胁迫24h后棉花叶片中的相对表达量,并选取质量好、实验重复性高的10个特异的差异表达蛋白质点进行基质辅助激光解吸电离串联飞行时间质谱(MALDI-TOF-TOF/MS)鉴定。结果表明,从对照和盐胁迫处理的双向电泳图谱中共检测到24个差异蛋白质点,这些差异蛋白质点的等电点分布集中在5.0～6.5之间,分子量分布集中在40.0～110.0kD之间;进一步质谱(MALDI-TOF-TOF/MS)分析鉴定的10个差异蛋白质点,其中4个蛋白质点获得了鉴定结果,这4个差异表达蛋白质点分别为1,5-二磷酸核酮糖羧化/氧化激酶α2(编号4)、1,5-二磷酸核酮糖羧化酶/氧化酶大亚基(编号5)、未知蛋白产物(编号19)和OEE2(编号32)。我们初步推测OEE2和1,5-二磷酸核酮糖羧化酶/氧化酶可能与棉花耐盐胁迫特性有关。     

毛白杨植物络合素合酶(PtPCS)基因克隆及其表达研究

植物络合素(PCs)是植物细胞中一类螯合重金属离子的多肽,对细胞解毒和重金属的富集有重要的作用。植物络合素合酶(PCS)是合成PCs途径中的关键酶。本研究克隆了毛白杨的植物络合素合酶基因PtPCS,该基因cDNA序列全长1512bp,可编码503个氨基酸;与其它8种植物同源基因比对显示,它们的氨基酸序列相似性在67%～74.1%之间;构建进化树发现,这9种植物明显的分为两大分支,并且两大分支PCS蛋白的高级结构显示出明显的差异,一种呈月牙状,一种为伞状,重金属超富集植物均为月牙状结构。对毛白杨在不同镉浓度处理下PtPCS基因的表达情况分析发现,毛白杨根、茎、叶中PtPCS基因均表现出先升高后缓慢降低的表达趋势,并且在同一镉浓度处理下,毛白杨不同器官PtPCS基因的表达具有规律性,即根表达量最强,茎次之,叶片最弱。研究结果不仅为植物育种提供了重要的基因资源,也为剖析毛白杨的镉抗性和富集特性的研究奠定了良好的基础。     

毛白杨PtAUX1超表达诱导体状胚发生

体状胚的发生由一个生长素信号级联系统控制,其发生过程需要大量的生长素,随后在去除生长素或降低生长素浓度的条件下,体状胚趋于成熟。除植物激素外,环境胁迫也是体状胚发生所必须的,激素和环境胁迫协同诱导细胞的脱分化、再分化和体状胚的发生。目前发现的参与体状胚发生的主要基因有SERK、PKL和BBM等,它们作用于体状胚的不同发育阶段。本研究中,在毛白杨35S::PtAUX1超表达植株中发现叶片表面产生大量体状胚,体状胚分散在叶片主脉及侧脉两侧或聚集在叶片边缘,其中部分体状胚可发育成成熟体状胚。将成熟体状胚取下,置于MS0培养基上进行培养,体状胚发芽并缓慢产生根。研究结果表明,PtAUX1通过建立新的生长素浓度梯度,诱导体细胞转化成胚性细胞,从而使叶片产生出体状胚。除上述基因外,PtAUX1也参与体状胚的发生,这一研究发现现尚未见报道。     

不同光环境下6种常绿阔叶林树种苗期的叶片功能性状

研究不同光环境(旷地、林窗、林下)下缙云山常绿阔叶林6种常见树种的叶片功能性状及性状间的相互关系,并对不同演替阶段物种的叶片性状进行比较.结果表明:1)在光照较弱的林窗和林下,树种的比叶面积(SLA)、叶片氮含量(LNC)和叶片N:P比显著高于光照充足的旷地,叶干物质含量(LDMC)变化趋势与SLA相反,叶片磷含量(LPC)在3种光环境下无显著差异;2)演替前期种具有较高的SLA,LNC和LPC,而演替后期种的LDMC和N:P比显著高于演替前期种.随光照的减弱,演替前期种的LPC无显著差异,而演替后期种则呈下降趋势;3)在3种光环境下,LNC与LPC,SLA正相关,LDMC与LPC,LNC,SLA负相关,N:P比与LPC负相关,而与LNC无显著相关性.随光照的减弱,SLA-LDMC,LPC-N:P及LNC-LPC性状关系沿共同斜率或Y轴截距发生了显著的变异,表明研究材料主要通过增大SLA,LNC及维持较高的N:P比来适应低光环境,不同演替阶段物种适应策略不同;叶功能性状间的权衡关系沿光资源梯度发生了相应的变化.     

Study of the soil-plant (carrot)-animal cycle of nutritive and hazardous minerals in a rabbit model.

Carrots were grown on soils polluted by heavy metal salts. Each particular microelement reached a high concentration [molybdenum (Mo) 39.00, cadmium (Cd) 2.30, lead (Pb) 4.01, mercury (Hg) 30.00, and selenium (Se) 36.20 mg/kg dry matter] in the carrot. In a metabolic balance trial conducted with 15 male and 15 female New Zealand White rabbits, the control animals (n = 5) were fed ad libitum with concentrate as basal diet, while the other rabbits received the basal diet and carrots containing the particular microelement. Blood samples were taken to determine the activity of serum enzymes. To investigate the metabolism of Mo, Cd, Pb, Hg and Se, samples were taken from the heart, liver, lungs, kidneys, spleen, ovaries/testicles, entire digestive tract, adipose tissue, femur, hair, faeces and urine. Carrot had significantly higher digestibility for all nutrients than the rabbit concentrate. Carrot samples of high Pb content had the lowest digestibility of crude protein. The microelements differed in their rate of accumulation in the organs examined: Mo and Cd accumulated in the kidneys, Pb in the kidneys, liver, bones and lungs, Hg in the kidneys and liver, while Se in the liver, kidneys and heart. The proportions of microelements eliminated from the body either via the faeces and urine (Mo 80.18% and Se 47.41%) or via the faeces (Cd 37.86%, Pb 66.39%, Hg 64.65%) were determined. Pathohistological examination revealed that the rate of spermatogenesis was reduced in the Mo, Cd, Pb and Hg groups compared to the control. Lead, Cd and Hg intake resulted in a considerable decrease in gamma-glutamyltransferase (GGT) and in an increase of alkaline phosphatase (ALP) activity because of damages to the kidneys and bones. All experimental treatments decreased the activity of cholinesterase (CHE) because of lesions in the liver.     

将透明颤菌血红蛋白基因(vgb)转移到链霉菌染色体整合载体的构建

链霉菌抗生素的生物合成对培养环境中氧的供应相当敏感,为了改善这一溶氧问题,本研究通过将透明颤菌血红蛋白基因(vgb)克隆到含ФC31int,attP基因的诱导型表达载体pU8600上,构建了可接合转移到链霉菌的整合型表达vgb基因的质粒pHZ1276。pHZ1276通过接合转移导入变铅青链霉菌(Streptomyces lividans),所得重组子经Southern杂交验证后,进行诱导表达,菌体经破碎后所得蛋白粗提物经Western杂交和CO结合试验表明vgb基因在该菌中表达出了有活性的VHb蛋白。     

Isolation of infectious microalga Prototheca wickerhamii from a carp (Cyprinus carpio) – a first confirmed case report of protothecosis in a fish

Protothecosis is a rare infection caused by environmentally ubiquitous achlorophyllic microalgae of the genus Prototheca. Here, we describe a first case of protothecosis in a carp (Cyprinus carpio), which is at the same time the first case of protothecosis in a fish, confirmed by phenotype‐ and molecular‐based methods, including PCR sequencing of the rDNA cluster and protein profiling using matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry.