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THE EFFECT OF GENES ON THE DEVELOPMENT OF SIZE AND FORM 总被引:1,自引:0,他引:1
E. W. SINNOTT L. C. DUNN 《Biological reviews of the Cambridge Philosophical Society》1935,10(2):123-151
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Abstract— The phospholipid content and composition of the different regions of the developing human brain were studied. Brains from 25 fetuses and 9 infants, aged 13 weeks gestation to 26 months, were analysed. The concentration of total lipid-P was highest in the brain stem and lowest in the cerebellum at any age. Compared with the forebrain or brain stem, the cerebellum had a sharp phospholipid growth spurt between 3 months before and 6 months after birth. Before birth, the phospholipid pattern was similar in each part of the brain, with choline phosphoglycerides as the major phospholipid. After birth, the pattern in the brain stem changed further and ethanolamine phosphoglycerides became the dominant phospholipid, while in the other two there was little change. In all parts of the brain the proportion of sphingomyelin increased. The relative proportion of serine and inositol phosphoglycerides remained almost constant throughout the whole period of development. The possible significances of the changes in the phospholipids in neurological development are discussed. 相似文献
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THE EFFECT OF DEVELOPMENT ON THE GANGLIOSIDES OF RAT AND PIG BRAIN 总被引:10,自引:8,他引:2
Abstract— The ganglioside content of the forebrain, brain stem and cerebellum have been studied, in the rat at various ages from 1 day to 27 months, and in the pig at various ages from 93 days gestation to 30 months. Each part of the brain was analysed for total ganglioside NANA and for four major gangliosides (GMl , GD1a , GDlb and GT1 in the nomenclature of S vennerholm , 1963). In the rat forebrain, the concentration of ganglioside NANA rose rapidly between 1 and 21 days after birth, fell to 3 months and subsequently rose to a mature value at 6 months. In the rat cerebellum, the peak concentration was reached at 2 months and the lower adult value at 9 months, whilst in the brain stern, the concentration rose more slowly and had a broad peak from 15 days to 2 months. Values are also given for the changes in the total amounts in each brain part. The changes in the concentrations and total amounts of ganglioside NANA, in the three parts of the pig brain were, on the whole, similar to those in rat brain except that the percentage distribution of the major gangliosides had almost attained the mature pattern at birth. In the forebrain of both species, the disialoganglioside, GD1a , accounted for the highest percentage of the total gangliosides. The results are discussed with respect to their possible structural significance. 相似文献
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菊叶薯蓣生长发育的研究 总被引:7,自引:0,他引:7
一种原产墨西哥的提取薯蓣皂甙元(diosgenin)的重要原料植物菊叶薯蓣(Dioscorea composite Hemsl.),首次在我国西双版纳引种成功,试验结果表明,种子萌发以35℃最为适宜,种子千粒重达9克者,发芽率最高,可达90%以上,种子贮存期在3-4个月内,发芽率高而整齐,播种60天藤蔓开始有缠绕能力,可以移栽,移栽后12个月出现花蕾,开花结果,每年两次花果期,营养生长与生殖生长交驻沪进行,叶终年常绿,埠茎常年生长,产量逐年增加,栽培三年最高亩产鲜块茎5494公斤(按单株测产)。粗皂甙元含量3-4%(干样)。粗皂甙元重结晶一次溶点203-206℃,有利用价值。 相似文献
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台湾林檎生长发育生物学特性的观察研究 总被引:3,自引:0,他引:3
台湾林檎(Malusdoumeri(Bois.)chev.)是蔷薇科苹果属植物。主要对其生长发育生物学特性进行了研究,掌握它的生长发育规律,为进一步的开发利用提供参考。 相似文献
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探讨了植物生理生态学的起源及其发展问题。植物生理生态学是植物生态学的一个分支,它主要是用生理的观点和方法来分析生态学现象。从现有的资料看,该门学科的创始人当为德国学者辛泊尔(A. F. W. Schimper);但近代最早建议将植物生理生态学作为独立的学科的为比林斯(W. D. Billings);拉夏埃尔(W. Larcher)为该门学科在国际上的传播起到了非常重要的作用。在中国,近代植物生理生态学的发展应归功于李继侗先生;然而,李博先生对拉夏埃尔《植物生理生态学》的翻译出版促进了该门学科在中国的传播。植物生理生态学目前在国内外发展十分迅速,由于它能够对一些生态学现象以及资源的可持续利用给以机理上的解释,因此越来越受到研究者的重视。 相似文献
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①泡桐属植物以虫媒传粉,在柱头室内萌发为花粉管。②从传粉至受精需时11—20天。花冠脱落后受精,受精后花柱呈现紫色。③为有胚乳种子,胚乳发育为细胞型,第一次分裂为横分裂并具有两个吸器。④胚的发育为十字花型,胚柄将胚推移到胚囊深处,当胚开始分化时,胚柄即消失。⑤种皮扩展为扁而薄的翅状,由栓化细胞构成。⑥果实为蒴果,发育期约半年,可划分为迅速增长期、缓慢增长期、充实成熟期三期。 相似文献
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蕨类植物桂皮紫萁颈卵器和精子器形态和发育的研究 总被引:5,自引:0,他引:5
利用扫描电镜技术和树脂切片技术对蕨类植物桂皮紫萁(Osmunda cinnamomeaL.var.asiatica Fernald)的颈卵器和精子器的形态和发育进行了细致的研究。颈卵器发生于雌配子体的腹面,颈部由4列壁细胞构成,6-7个细胞高,内部含有颈沟细胞,腹沟细胞和卵细胞,卵细胞在整个发育过程中,造粉体和囊泡最为显著,颈卵器内的卵细胞成熟时产生卵膜和分离腔。精子器发生于雄配子体的边缘及腹面,由7-8个壁细胞螺旋状围绕而成,壁细胞内为产精组织,精子成熟时精子器盖细胞开裂释放出游动精子。 相似文献
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温度和食物对虎纹捕鸟蛛发育和繁殖力影响的研究 总被引:1,自引:2,他引:1
研究不同温度和食物对虎纹捕鸟蛛生长发育和繁殖力的影响,结果表明,虎纹捕鸟蛛在24℃-26℃变温范围,饲以人工混合饲料溶液时生长发育最快,在这个温度范围外饲以单一食物为最低。最有利于虎纹捕鸟蛛繁殖的因子水平组合为24℃-26℃,食物为人工混合饲料溶液。 相似文献
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生长在湖南江河、池塘、水库环境的银鲴,性成熟年龄一般是二冬龄(2+),雄性比雌性提前一年成熟。江河银鲴每到生殖季节,可以自行产卵、受精,繁衍后代;池养银鲴却不能自然产卵,其卵母细胞只能发育到初级卵母细胞阶段(Ⅳ时相),必须通过人工催情,才使卵母细咆由第Ⅳ时相发育到第Ⅴ时相。池养雄性银鲴,能够完成由精原细胞到精子的全部发育过程。冬季,达性成熟的银鲴,雌性卵巢为Ⅲ期,雄性精巢为Ⅳ期。每年的3月份,银鲴开始进入性成熟期,4月份为它的生殖盛期。银鲴是鲴亚科中产半浮性卵的鱼类。银鲴在胚胎发育早期行盘状卵裂。当水温21—23℃时,其胚胎发育历经26小时10分,胚胎发育总热量为550—602度时;银鲴从受精卵到仔鱼期结束(鱼苗下池),整个过程历时112小时,区分胚胎发育、仔鱼发育两个阶段。胚胎发育又划为5个时期。
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BY GUNNAR BERTMAR 《Journal of Zoology》1965,144(1):87-129
The development of the jugular and cerebral veins and adjacent lymphatic vessels in Hepsetus, Salmo, Amia, Acipenser, Neoceratodus, Scyllium and Squalus has been studied on a large embryological material. The reconstruction method has been applied. There has been much confusion in the literature on head veins. This is partly due to the rather schematic investigations of e.g. van Gelderen, and partly to the publications of de Beer and Holmgren, paying no regard to the lymphatic vessels. The currently new features on the v. capitis medialis are that in adult fishes a larger part of the vein remains than was earlier believed. It usually consists of three portions. No secondary vein takes part in the constitution of the jugular vein, as was supposed by de Beer, Holmgren and others. In actinopterygians the secondary vein is in reality represented by the anterior portion of the v. cardinalis anterior as well as of all the v. capitis lateralis, and in elasmobranchs it is only represented by the former portion. The elasmobranchian (except Squalus ) jugular vein is instead formed from the v. capitis lateralis, and in teleostomes and Squalus it is developed from two veins, viz. the anterior portion of the v. capitis medialis and all the v. capitis lateralis. The latter vein is formed from two (teleostomes) or three (elasmobranchs) loops. The v. cardinalis anterior becomes completely atrophied in Squalus , and partly atrophied in Acipenser, Amia and Neoceratodus. The development of the three main cerebral veins is described. van Gelderen's classification of the v. cerebralis media is criticized. And so also is his hypothesis for the evolution of the head veins in fishes. It is suggested that the Hepsetus type is primitive and that the Acipenser and Amia types have evolved from it or from a similar type. Neoceratodus and Squalus have rather specialised types, which seem to have evolved separately right from the base of the system. 相似文献
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啤酒酵母的开发应用及其制代可可粉的研究 总被引:1,自引:0,他引:1
本文介绍了啤酒酵母营养的成分和医用价值,概述了国内外开发应用啤酒酵母的研究功态,研究了用啤酒酵母加工代可可粉的工艺路线和方法,同时回收了啤酒,测定了代可可粉的营养成分,并用之加工巧克力和可可饮料,结果表明,其效果与天然可可粉类同。 相似文献