体细胞数对发酵乳品质的影响研究

为确定用于生产发酵乳的原料乳质量标准,以提高发酵乳产品品质,选用蒙牛自有牧场30头不同健康状况、不同泌乳期的荷斯坦牛原料乳,按体细胞数分为低于20万个/mL组、20万-80万个/mL组及大于80万个/mL组,在发酵乳制备的当天及样品冷藏后的第1、7、14、21天分别测定发酵的产酸曲线、发酵乳的质构特性。结果表明,随着原料乳中体细胞数的增加,产品黏度下降,弹性降低,硬度增加,pH值降低,品质下降。     

奶牛乳体细胞数变化及影响因素调查

调查分析了大庆地区四个规模化牧场近3年奶牛DHI数据。结果表明,乳体细胞评分均值为5.05(其乳体细胞数均值为49万·mL-1)。75.75%的奶牛个体,其生鲜乳体细胞数小于50万·mL-1。胎次、泌乳阶段、自然月份等因素影响奶牛生鲜乳体细胞数。调查结果为牛场奶牛综合管理及制定科学可行的乳房炎防治措施提供依据。     

马尾松体细胞胚胎发生相关基因PmSERKl的克隆与表达分析

体细胞胚胎发生不仅是植物微繁、种质保存的有效手段，同时也是研究高等植物胚胎发育和遗传转化的模式系统之一。本研究从马尾松未成熟合子胚诱导的胚性细胞团中成功克隆了体胚发生受体激酶基因PmSERK1。该基因全长2303bp，包含完整的开放阅读框，编码626个氨基酸，其蛋白分子量约为69kD。序列分析发现PmSERK1与其它植物的SERK基因高度同源。系统进化树重建表明，PmSERK1与已知参与体胚发生的关键SERK基因聚为一类，如MtSERK1、CuSERK1、AtSERK，和DcSERK。表达分析显示：PmSERK1在主要的组织器官（根、茎、针叶等）略有表达；但在诱导培养的非胚性愈伤中没有检测到表达，而在经继代培养的胚性愈伤中表达很高且逐渐增加，且在培养20d时达到最高。另外，在再生的子叶胚中，PmSERK1的表达量也很高。综上所述表明，PmSERK1是与体胚发生相关的关键SERK基因的直系同源基因，可以作为愈伤组织胚性的标记基因。     

Incongruity of interspecific and intergeneric crosses involving Nicotiana and Petunia species that exhibit potential for somatic hybridization

Summary Extensive pollinations were made in attempts to produce selected intergeneric or interspecific hybrids using Nicotiana and Petunia species that exhibit potential for somatic hybridization. Pollination between pairs of species was done by standard and bud-pollination methods. Nicotiana alata or N. tabacum when pollinated reciprocally with selected Petunia species failed to produce hybrids. Likewise, no interspecific hybrids were obtained between Petunia parviflora and 4 Petunia species or P. hybrida. The type of incongruity existing between these species is discussed in relation to the production of hybrids by standard In vitro techniques as compared to somatic hybridization.On leave from the Department of Horticulture, Michigan State University, E. Lansing, Michigan, USA. supported by a European Molecular Biology Organization (EMBO) fellowship and The Fred C. Gloeckner Foundation, N. Y., USA.Supported by the Agricultural Research Council.     

Somatic hybridization as a tool for tomato breeding

Protoplast fusion can be used to produce somatic hybrids of species that cannot be obtained by sexual hybridization. The possibility to introgress genes from Solanum species into the cultivated tomato species Lycopersicon esculentum, and to obtain novel cytoplasm-nucleus combinations (cybrids) was considered as an important strategy to extend the genetic variation available for tomato breeding. Somatic hybrids between L. esculentum and other Lycopersicon species, as well as between L. esculentum and Solanum or Nicotiana species, have been produced. Specific mutants, genotypes with antibiotic resistances, and metabolic inhibition by iodoacetate or iodoacetamide and irradiation were used for the selection of hybrids. In addition, the improvement of protoplast culture techniques and the use of the favourable tissue culture traits derived from species such as L. peruvianum, which have been introduced into tomato by classical breeding, allowed the efficient recovery of somatic hybrids. However, the occurrence of somatic incongruity in fusion combinations of L. esculentum and Solanum and even more in L. esculentum and Nicotiana, did not allow the production of true cybrids and/or fertile hybrids, indicating the importance of both cytoplasm-nucleus and nucleus-nucleus interactions in somatic incongruity. Another problem with fusions between distantly related species is the strongly reduced fertility of the hybrids and the very limited homoeologous recombination between chromosomes of the parental species. Partial genome transfer from donor to recipient through microprotoplast (+) protoplast fusion, and the production of monosomic or disomic chromosome addition lines, light overcome some of these problems. In symmetric somatic hybrids between L. esculentum and S. tuberosum the occurrence of limited somatic and meiotic recombination was demonstrated. Fertile progeny plants could be obtained, though at a low frequency, when embryo rescue was performed on a large scale after backcrossing hexaploid somatic tomato (+) potato hybrids with a tetraploid potato genotype. The potential value of genomic in situ hybridization (GISH) and RFLPs for the analysis of the genome/chromosome composition of the hybrids has been demonstrated for intergeneric somatic hybrids between Lycopersicon and Solanum.Abbreviations cpDNA chloroplast DNA - mtDNA mitochondrial DNA     

利用SSH技术鉴定香蕉体细胞胚发生相关基因

本研究以野生蕉胚性悬浮系为材料,将胚性细胞增殖培养基上的香焦胚性悬浮系作为对照,体胚诱导培养基上的培养材料为处理,利用抑制性消减杂交(suppression subtractive hybridization,SSH)技术,构建野生蕉胚性悬浮系激素诱导的胚胎发育差异表达cDNA文库,随机挑选阳性克隆并进行生物信息学分析...     

大豆体细胞胚胎发生及植株再生

以野生大豆（ＧｌｙｃｉｎｅｓｏｊａｓｉｅｂｅｔＺｕｃｃ）三个品系、半野生大豆（Ｇｌｙｃｉｎｅｇｒａｃｉｌｉｓｓｋｖ）１个品系、栽培大豆（ＧｌｙｃｉｎｅｍａｘＬＭｅｒｒｉｌ）４个品系为材料，进行组织培养．探讨了大豆体细胞组织再生植株的主要影响因素，并以器官分化和体细胞胚两种不同方式再生完整大豆植株。     

鸡躯体和内脏初级传入纤维在脊髓和延髓的共同投射

采用ＣＢ—ＨＲＰ跨神经节追踪技术，我们发现鸡躯体和内脏的初级传入投射在脊髓质的一些板层和延髓的一些核团内有重叠区。１腓肠肌外头与卵巢的初级传入在Ｔ６～Ｌ３及Ｓ３～Ｓ５脊髓节段的Ｉ、Ⅴ层有明显的投射重叠区；与睾丸的初级传入在Ｔ６～Ｌ２及Ｓ３～Ｓ５髓节的Ｉ、Ⅴ层有明显的投射重叠；与泄殖腔的初级传入在Ｔ７～Ｌ２及Ｓ３～Ｓ５髓节的Ｉ、Ⅴ层亦有明显的重叠投射。２跗部皮肤与泄殖腔的在Ｌ２及Ｓ３髓节的Ｉ、Ⅳ层，与卵巢的在Ｌ２～Ｌ３髓节的Ｉ、Ⅳ层，与睾丸的在Ｌ３及Ｓ３髓节的Ｉ、Ⅳ层均有轻度的投射重叠区。３挠神经与腺胃及胸腺的在延髓的楔束外核和弧束核的内侧亚核有重叠投射区，４挠神经与卵巢、睾丸的在孤束核的内侧亚核有重叠；推测鸡的躯体和内脏的初级传入在这些区域可能有汇聚。     

苹果离体叶片培养直接体细胞胚胎发生研究

在ＭＳ＋ＢＡ１０ｍｇ／Ｌ＋ＮＡＡ５０ｍｇ／Ｌ＋２，４＿Ｄ０＼＾５ｍｇ／Ｌ＋蔗糖２０ｇ／Ｌ的固体培养基上，苹果品种嗄拉试管苗叶片经７天暗培养产生胚性细胞。将具有胚性细胞的叶片转入ＭＳ＋ＢＡ１０ｍｇ／Ｌ＋蔗糖２０ｇ／Ｌ的培养基上暗培养４０天，６５％的叶片直接发生体细胞胚，体细胞胚在同种培养基上萌发，长成小植株。