Embryonic expression of UCP2 in rainbow trout (Oncorhynchus mykiss)

Uncoupling proteins are mitochondrial anions transporters that dissociate respiration from ATP synthesis through proton leaks. Uncoupling protein 2 reportedly plays a role in several physiological processes such as energy partitioning, nutrition, and fatty acid metabolism. The mRNA expression of rainbow trout UCP2 genes (UCP2A and UCP2B) was monitored during embryogenesis and early larval development. Both genes were recruited early and displayed similar steadily decreasing patterns from fertilization until hatching. The expression of UCP2A and UCP2B appeared significantly differentiated after hatching and during the yolk sac absorption, with UCP2A displaying higher expression. We suggest that UCP2 expression profiles in the rainbow trout embryo could be associated with the utilization of lipids as a source of energy during development.     

东北红豆杉配子形成与胚胎发育解剖观察1）

利用显微技术观察了东北红豆杉雌、雄配子形成和胚胎发育过程。结果表明：直生胚珠3月份恢复发育,5月中旬大孢子母细胞形成,下旬减数分裂,6月中、下旬雌配子体形成。3月中旬花粉母细胞减数分裂,经过1个月左右发育为成熟的单核花粉,4月底至5月初散粉。传粉后约2个月受精,受精后的原胚经历球形胚、卵形胚、柳叶形胚、棒槌形胚,进而发育成具有胚芽、胚根、胚轴和子叶的胚体。     

Early development of the shortfin silverside Chirostoma humboldtianum (Valenciennes, 1835) (Atheriniformes: Atherinopsidae)

The shortfin silverside Chirostoma humboldtianum has been considered for culture in Mexico, but success has been limited by a poor knowledge of its early development. First synthesis of the early development of the shortfin silverside is presented to determine conditions suitable for rearing. Brooder maturation was induced through photothermal cycles. C. humboldtianum ova were fertilized in vitro. The eggs were incubated in reconstituted water (160-180 mg/L CaCO₃) at 18 °C and 5 gm of NaCl per litre. During the hatching day, 300 shortfin silversides were stocked and followed up until metamorphosis in order to establish the timing of exogenous feeding, changes in food type, growth and development during critical periods for survival, according to the theory of saltatory ontogeny. Free embryos hatched 12 days after fertilization at 18 °C. First critical point for survival is the beginning of exogenous feeding. Free embryos started mixed feeding on day four of post-hatching (dph), point of no-return was presented towards the end of mixed feeding on 6 dph, larval period began at six (dph) when the anus is opened, and metamorphosis to juvenile was presented at 65 dph with a SL of 19.34 ± 2.28 mm, when scales and fins were well developed. Differences in growth between periods were detected: free embryos growth slower than larvae but mouth size depicted a larger growth rate in the former. Cephalic length and mouth size were negatively related to standard length in embryos and larvae. Mouth size was positively related to cephalic length in free embryos but negative in larvae. Results suggest that during the free embryo phase, growth priorities are directed to the development of apparatuses and systems; whereas, during the larval period, energy is directed to growth in length, mouth size and development of fins, which allows them to increase their swimming velocity, grants them a greater capacity to obtain exogenous food and, in consequence, increases fitness for survival.     

Improving the Field Emergence Performance of Super Sweet Corn by Sand Priming

Abstract

A priming method called sand priming was developed using sand as a priming solid matrix. The effect of sand priming on improving the field emergence performance of five super sweet corn cultivars was investigated. Sand priming significantly improved field emergence performance of all super sweet corn cultivars, and there was marked improvement by priming at 20ºC for 24 hr. After sand priming at 20ºC for 24 hr, field emergence percentage (FEP) of “Green Superman”, “Huatian 1”, “Yangtian 1”, “Mitian 8”, and “Chaotian 43” was increased by 52.1%, 37.5%, 38.0%, 40.9%, and 33.3%, respectively. Their field emergence speed (FES) was 2.3, 1.8, 2.0, 2.0, and 1.8 times of the control, respectively. To further elucidate the effect of sand priming on improving the field emergence performance of super sweet corn, we analyzed the membrane system integrity, α-amylase activity and protein content. Sand priming at 20ºC for 24 hr improved membrane system integrity and α-amylase activity in all super sweet corn cultivars. Furthermore, sand priming at 20ºC for 24 hr accelerated the degradation of embryo protein after 1 d germination in “Green Superman”.     

西部农村发展奶牛小区的优势及注意问题

西部农村饲草资源充裕,发展奶牛养殖小区有利于减少草料运输费用,有利于减轻城郊养牛环境污染,有利于改善牛奶质量。本文提出小区建设应注意的五个问题:注重奶牛质量;采用胚胎移植技术,提高小区牛群的个体产奶量:种养结合,建立与奶牛养殖业配套的饲草生产基地;改进饲养管理,推行混合日粮饲养技术;实行行业准入制度,控制小区环境污染,提高牛奶质量,生产绿色奶品。     

牛胚胎玻璃化冷冻技术的发展和应用概况

胚胎冷冻保存是动物胚胎工程的重要组成部分，它是胚胎移植技术在生产中推广应用的重要基础。和现在通用的常规冷冻法相比，玻璃化冷冻具有用时短，所需设备少和操作简单等优点，成为目前国内外胚胎冷冻保存领域发展新方向。本文就牛胚胎玻璃化冷冻的概念、方法和国内外发展状况做一简要综述。     

陆地棉×亚洲棉F_0成胚频数与亲本主要产量性状配合力的关系

陆地棉×亚洲棉F_0成胚频数主要受母本陆地棉的影响,不同的7个陆地棉品种间存在着显著差异.成胚频数高的6901和朝阳1号,单铃子棉重、单铃种子数、子指一般配合力亦均高;而成胚频数低的6913和黑山棉,上述各性状的一般配合力也均低.在7个父本亚洲棉中,与陆地棉杂交当代成胚频数高的束鹿白花和完紫,其子指的一般配合力也较高.因此,选择单铃子棉重、单铃种子数、子指一般配合力较高的陆地棉作母本与子指一般配合力较高的亚洲棉作父本杂交,可以显著提高种间杂交当代的成胚频数.     

血管内皮生长因子及其受体在胚胎卵黄囊 不同发育时期的表达

为研究胚胎不同时期VEGF、KDR和CD34在人卵黄囊中的表达情况，了解胚胎造血的发育过程和机理。采用免疫组织化学SP法卵黄囊冰冻切片进行染色，光镜观察。结果发现在第3~4周的人卵黄囊低表达VEGF和KDR，不表达CD34。4~6周组强表达VEGF、KDR和CD34。在血岛内阳性细胞大而圆，成簇或分散聚集，有些细胞沿血岛边缘形成血管样结构。6周以后，卵黄囊弱表达VEGF、KDR和CD34。上述结果提示卵黄囊可表达造血和血管生成相关因子，随胚胎发育呈阶段性表达。卵黄囊中出现造血干细胞和血管内皮细胞的分化。     

应用国产激素进行奶牛超数排卵的研究

研究了国产激素(FSH)在使用方法、时间、剂量、配制比例等方面对奶牛超数排卵效果的影响,并对供体牛的年龄、胎次、产后日期,重复超排及季节、气候等各种因素在超数排卵效果方面进行了探讨。研究结果还表明国产FSH超排效果比较稳定。     

Factors Affecting the Efficiency of Embryonic Cell Nuclear Transfer in Rabbits

Factors affecting the efficiency of nuclear transfer （NT） in rabbits were examined in the present study. When 100 V mm of pulse strength and 15 us of pulse duration were employed, 3 and 4 electronic pulses resulted in significantly more cytoplasts fused with donor cells compared with 2 electronic pulses （P〈 0.05）, but no significant difference was found in the cleavage rate of reconstructed embryos among the three groups （P〉0.05）. When the duration and number of electronic pulse were fixed at 15 ps and 3 times, increase of pulse intensity from 100 V mm 1 to 150 V mm^-1 and 200 V mm^-1 resulted in a significantly decrease in the cleavage rate of reconstructed embryos （P〈 0.05）, although the fusion rate did not significantly differ among the three groups （P〉 0.05）. Significantly more reconstructed embryos cleaved and developed to blastocysts when they were derived from donor embryos at the 8-16-cell stage, in comparison with the reconstructed embryos derived from donor embryos at the compact morula stage （P 〈 0.05）, although the fusion rate was similar （P 〉 0.05）. Activation of cytoplasts prior to fusion increased the cleavage rate （P〈 0.05） and blastocyst development （P〈 0.05） of reconstructed embryos, but decreased the fusion rate （P 〈 0.05） compared with cytoplasts activated post fusion. More reconstructed embryos developed to blastocysts when they were cultured in TCM ＋ 3% OCS at the first 48 h and then cultured in TCM199＋ 10% FCS, in comparison with the reconstructed embryos cultured in either TCM199＋ 10% FCS or TCM199＋3% OCS （P 〈 0.05）. When 22 NT embryos were transferred into the oviducts of one recipient rabbit, one recipient rabbit delivered a female rabbit at 34 days of gestation. In conclusion, either electrofusion parameter or developmental stage of donor embryos have a significant effect on the efficiency of NT, NT embryos require different concentration of serum at their different development stages.