Ontogeny of calbindin-D28K and calretinin in developing chick kidney

The ontogeny of two calcium-binding proteins (calbindin-D_28k and calretinin) was studied by immunohistochemical techniques in developing chick kidney. This study showed the presence of calbindin on the 5th incubation day and calretinin on the 7th incubation day in mesonephric distal and connecting tubules, and in the medial wall of the Wolffian duct. At later stages, immunostaining for these two proteins, in particular for calretinin, was also demonstrated in some metanephric proximal tubules. Glomeruli and Bowman's capsules were negative both in the mesonephros and metanephros. The presence of calretinin in the developing kidney has thus been demonstrated for the first time. The early expression of calbindin and calretinin in mesonephric distal tubules suggests their role in regulating the final excretion of calcium. The different patterns of immunoreactivity of the walls of the Wolffian duct can be correlated with their different histogenetic and histological features.     

罗汉果胚、胚乳及胚乳吸器的发育

本文采用石蜡切片与酶解分离法对罗汉果Ｓｉｒａｉｔｉａｇｒｏｓｖｅｎｏｒｉ胚、胚乳及胚乳吸器的发育过程进行观察．ａ）罗汉果胚的发育是按Ｇｅｕｍｕｒｂａｎｕｍ的分裂程序进行的．属紫菀型．但在合子分裂成球胚过程中,胚芽原细胞分化明显．故属紫菀型的变异型。ｂ）胚乳发育属核型．在球形胚阶段,在合点端和珠孔端有发育的胚乳吸器形成并进行旺盛生长,最大长度达１４２０μｍ,心形胚期．吸器活动开始减退,合点端核型胚乳吸器转变成细胞型．由胚乳本体基部膨大细胞．充当补助吸器．ｃ）酶解分离法研究胚乳吸器的发生发育有较好的应用前景。     

Developmental potential of isolated blastomeres from early murine embryos

Experiments were designed to evaluate the effect of blastomere separation on blastocoele formation and development of viable fetuses. Two-cell and four-cell murine embryos were dissociated into individual blastomeres and cultured to the blastocyst stage. For embryos of both stages, zona removal and blastomere separation reduced (P<0.05) the number of viable embryos at the onset of culture and reduced (P<0.01) the frequency of continuation of development of blastomeres to the blastocyst stage. Attempts to repeatedly split two-cell stage embryos decreased in vitro development to blastocysts. The number of cells in two-cell embryos that were cultured to blastocyst was not different for control (64.8 +/- 11.5) or for two-cell embryos cultured without the zona pellucida (60.9 +/- 10.1) but was reduced (P<0.01) for one-half embryos that were cultured to blastocysts (35.6 +/- 10.6). The cell number of blastocysts obtained from dissociated four-cell (1/4) embryos (17.4 +/- 1.4) was similarly reduced (P<0.01). In vivo development was assessed after cultured embryos were transferred to the uteri of day 3 pseudopregnant females. Zona free intact embryos (2/36, 6%) and zona free half embryos (7/36; 19%) developed less frequently (P<0.05) than intact controls (45/100). Noncultured morula briefly exposed to pronase to thin the zona had similar impaired development. Embryos with thinned zona or no zona developed less frequently (21/82, 2/72 respectively, P<0.05) than nonpronase-treated controls (50/83).     

Cattle breed as a source of variation in embryo transfer

The records of 1596 embryo collections were retrospectively analysed to investigate the influence of breed on embryo production and pregnancy rates. The breed of the donor cow was a significant source of variation in the results of embryo transfer. Total embryo production per collection ranged between breeds from 6.0 to 16.2, number of transferable embryos from 2.8 to 6.6 and percent transferable from 37% to 68%. The percent of pregnancies per collection ranged from 2.0 to 4.0 and pregnancy rates from 37% to 75%. The percent of transferable embryos and the pregnancy rate was independent of the total embryos collected. Care should be taken when interpreting the breed differences, since the donor cows were not randomly representative of the breeds and were selected on different bases. Brangus (16.2), Simbrah (15.8) and Beefmaster (13.0) produced the most embryos. The most transferable embryos were collected from Simmentals (6.6), Brangus (6.6), Chianina (6.2), Beefmaster (6.1), Simbrah (6.1) and Saler (6.0) cows. Angus (68%) had the highest percent transferable, followed by Saler (64%), Chianina (60%), Limousin (52%) and Simmental (51%). Pregnancy rates were highest in the Herefords (75%), Saler (57%), Zebu (56%), Charolais (53%), Longhorns (52%) and Simbrah (50%). Estrus response to superovulation varied between breeds, but this did not account for all the breed differences in embryo production.     

Postfixation embryo reduction in unilateral and bilateral twins in mares

Multiple ovulations were induced with a pituitary extract in mares, and the development of multiple conceptuses was monitored daily by ultrasound on days 11 to 40. The incidence of abortion (loss of all embryos) was not significantly different between mares with multiple embryos (5 38 mares; 13%) and mares with singletons (4 36 ; 11%). Embryo reduction (elimination of excess embryos) was not detected during the embryo mobility phase (days 11-15) or on the day of fixation of embryos (day 16) in any of 38 mares with multiple embryos. The incidence of postfixation embryo reduction for mares with twins was 64% (18 28 ); however, the incidence for unilateral twins (17 19 ; 89%) was greater (P<0.01) than for bilateral twins (1 9 ; 11%). Reduction of unilateral twin embryos seemed to occur earlier (53% before day 20 and 82% before day 30) than for the set of bilateral twins (day 36). The remaining embryo in all mares in which embryo reduction occurred seemed normal in size and appearance on the last day of examination. However, in four of eighteen mares in which unilateral reduction occurred, the umbilical cord of the remaining embryo was attached in the ventral hemisphere of the all antochorion. This apparent disorientation was not seen in any of 16 bilaterally located embryos or in 16 singletons.     

小鼠内细胞团标志蛋白的性质、分离和纯化

我们用二相电泳方法在小鼠畸胎瘤系统中发现小鼠胚胎内细胞团标志蛋白双联体(分子量39,000,p14.4—4.5)也存在于未分化的胚胎癌细胞株(PSAI-NG2、F9、PCC3)中,但在已分化细胞株滋养层母细胞癌TDM1中用二相电泳方法不能检查到这蛋白。把EC细胞分为细胞质、细胞核、染色体三部分再进行检查,可以清楚地看到这蛋白主要存在于染色体部分。把染色体再分成0.35M NaCl可溶性,2M NaCl可溶性及2M NaCl不溶性三个组份时,则这蛋白出现在0.35M NaCl可溶性组分中,表明它是与染色体疏松结合的非组蛋白染色体蛋白。这蛋白是一种耐热性蛋白,在80℃受热10分钟不能使它变性。用制备型SDS聚丙烯酰胺凝胶电泳对经热处理的0.36M NaCl可溶性染色体蛋白进行分离,可得到电泳纯的小鼠内细胞团标志蛋白。由于这蛋白约占细胞总蛋白0.6%,与染色体疏松结合,又与早期胚胎细胞的多能性相关,提示它在维持多能细胞染色体构象方面有重要作用。     

The origin,structure and occurrence of corpora amylacea in the bovine mammary gland and in milk

Summary Fibres growing from neurons of explanted dorsal root ganglia from 10 day chick embryos were transected and subsequently observed by light and electron microscopy after periods of a few to fifty minutes. Changes immediately proximal and distal to the cut together with alterations further away from the site of injury on both sides of the cut were recorded. Observations were also made on the growth cones of damaged axons and on changes in associated glial cells.Reactive and degenerative changes including the rotation, retraction and swelling of cut axons occurred rapidly. Electron microscopy revealed tracts of filamentous material close to the sealed-off ends of axons, swollen organelles such as mitochondria, and lamellar bodies of varying dimensions.Proximal to the injury and closer to the expiant, damaged and degenerating axons mingled with normal processes. Many contained only a fine granular material, others clumps of organelles, particularly mitochondria.Distal to the cut, microspikes were lost from some growth cones. The dense granular material filling microspikes and growth cones remained unchanged. Clumps of large clear vesicles, lamellar bodies and swollen degenerating mitochondria were present, not only within growth cones, but also in all parts of the axon distal to the cut.Glial cells associated with transected axons soon developed an electron dense cytoplasm containing swollen organelles. Large numbers of vesicles filled with a particulate substance were also found.The possible significance of the changes observed after transection are considered and discussed.The author wishes to thank Prof. D.W. James in whose laboratory at University College London these studies were initiated, Dr. A.R. Lieberman for his expert help and advice and the University of London Central Research Fund and Wellcome Trust for financial assistance     

Elevation of a threonine phospholipid in polyoma virus transformed hamster embryo fibroblasts.

Analysis of the lipids of normal hamster embryo fibroblasts and polyoma virus transformed fibroblasts shows a decrease in phosphatidylcholine and phosphatidylethanolamine and a marked increase in a threonine phospholipid after transformation. Transformed cells also react differently with fluorodinitrobenzene and trinitrobenzenesulfonate. phosphatidylethanolamine of transformed cells reacts to a greater extent with both probes. Phosphatidylserine and the threonine phospholipid of both cells do not react with trinitrobenzenesulfonate. The threonine phospholipid is provisionally identified as phosphatidylthreonine.