Somatic cell nuclear transfer using transported in vitro-matured oocytes in cynomolgus monkey

Somatic cell nuclear transfer (SCNT) is not successful so far in non-human primates. The objective of this study was to investigate the effects of stimulation cycles (first and repeat) on oocyte retrieval and in vitro maturation (IVM) and to evaluate the effects of stimulation cycles and donor cell type (cumulus and fetal skin fibroblasts) on efficiency of SCNT with transported IVM oocytes. In this study, 369 immature oocytes were collected laparoscopically at 24 h following human chorionic gonadotrophin (hCG) treatment from 12 cynomolgus macaque (Macaca fascicularis) in 24 stimulation cycles, and shipped in pre-equilibrated IVM medium for a 5 h journey, placed in a dry portable incubator (37 degrees C) without CO(2) supplement. A total of 70.6% (247/350) of immature oocytes reached metaphase II (MII) stage at 36 h after hCG administration, MII spindle could be seen clearly in 80.6% (104/129) of matured IVM oocytes under polarized microscopy. A total of 50.0% (37/74) of reconstructive SCNT embryos cleaved after activation; after cleavage, 37.8% (14/37) developed to the 8-cell stage and 8.1% (3/37) developed to morula, but unfortunately none developed to the blastocyst stage. Many more oocytes could be retrieved per cycle from monkeys in the first cycle than in repeated cycles (19.1 vs. 11.7, p < 0.05). There were no significant differences in the maturation rate (70.0 vs. 71.4%, p > 0.05) and MII spindle rate under polarized microscopy (76.4 vs. 86.0%, p > 0.05) between the first and repeat cycles. There were also no significant differences in the cleavage rate, and the 4-cell, 8-cell and morula development rate of SCNT embryos between the first and repeat cycles. When fibroblast cells and cumulus cells were used as the donor cells for SCNT, first cleavage rate was not significantly different, but 4-cell (50.0 vs. 88.9%, p < 0.05) and 8-cell (0 vs. 51.9%, p < 0.01) development rate were significantly lower for the former. In conclusion, the number of stimulation cycles has a significant effect on oocyte retrieval, but has no effect on maturation and SCNT embryo development; however, different donor cell types (cumulus and fibroblast) resulted in different developmental potentials of SCNT embryos.     

夜蛾趋光特性的研究:复眼反应与行为反应的相关现象

夜蛾对于波长的反应有很明显的选择性。在我们已经测验过的波长范围内,棉铃虫[Heliothis armigera (Hübner)]和烟青虫(Heliothis assulta Guenée)对333毫微米的紫外线趋性最强(丁岩钦等,1974);而粘虫(Leucania separata Walker)对于375毫微米的紫外线趋性最强(未发表资料)。但这些结果只能说明诱蛾光谱是决定诱蛾数量的一个重要因素。至于为什么不同的单色光能产生不同的引诱作用?为什么在田间还有不少蛾子降落在诱蛾灯周围而并不扑灯?怎样才能排除这种现象来更好地发挥光学防治的作用等等,都是需要解决的问题。     

红花蚜虫的研究

为害红花的蚜虫是蚜科长管蚜属的昆虫,其学名为Macrosiphum gobonis Matsumura. 在黑龙江省每年六月中旬,日平均温19℃时,是迁到红花始期,至七月下旬到八月上旬,日平均温22-26℃时,达到最大数量,九月上、中旬,日平均温在15℃时,离开红花,去浅土层内和牛蒡等菊科植物的叶背越冬。此蚜虫数量消长与温度、湿度、降雨量、播种期、品种、天敌、间作物、栽培地块等的影响均有密切关系。在防治方法方面,除使用药剂防治外,还可通过适期早播、选用抗虫品种及小面积上的红花与邓铃薯间作等途径。     

家蝇抗药性的研究——Ⅱ.选择作用对家蝇抗丙体666的影响

一、引言 在培养昆虫抗性的过程中,逐代的施用药剂,昆虫即发生抗性,并且在一定程度上随着培养代数的增多而杭性强度逐渐增加。昆虫的抗性从前一代可以影响到后一代,因此,目前大家公认昆虫的抗药性是可以遗传的。但产生抗性的原因,国际上尚有不同的看法,国内在1961年全国昆虫学会学术讨论会上亦有不同意见的争论。形成抗性遗传的不同     

三化螟发蛾产卵孵化及防治适期的初步研究

一、引言 三化螟系水稻栽培主要害虫,因气候不同,年生3至6代。在浙江省三化螟年生3至4代,主要为害双季连作晚稻、中稻和晚粳稻,造成枯心和白穗。近几年来因扩种连作稻,形成单季稻、双季稻混栽,引起了三化螟的猖獗为害;特别以晚粳稻区改种连作稻     

DGGE and 16S rDNA analysis reveals a highly diverse and rapidly colonising bacterial community on different substrates in the rumen of goats

In the rumen, plant particles are colonised and degraded by the rumen micro-organisms. Although numerous important findings about fibre-associated bacterial community were obtained using traditional or molecular techniques, little information is available on the dynamics of bacteria associated with feed particles during incubation in the rumen. In the present study, ryegrass leaf, ryegrass stem and rice straw, representing different carbohydrate compositions, were used as substrates and placed in the rumen of goats by using nylon bags, and PCR/DGGE (denaturing gradient gel electrophoresis) with subsequent sequence analysis were used to monitor the dynamics of and identify bacteria associated with the substrates during 24 h of incubation. DGGE results showed that substrate samples collected from 10 min to 6 h had similar DGGE patterns, with up to 24 predominant bands to each sample, including 14 common bands to all samples, suggesting a rapid and stable colonisation by a highly diverse bacterial community. Substrate samples collected at 12 and 24 h showed similar DGGE patterns but had great difference in DGGE patterns from those collected at 10 min to 6 h, suggesting an apparent shift in bacterial community. Sequence analysis indicated that most substrate-associated bacteria were closely related to fibrolytic bacteria. In conclusion, a highly diverse and similar rumen bacterial community could immediately colonise to different substrates and remained stable during the initial 6 h of incubation, but experienced a marked change after 12 h of incubation. Italian ryegrass leaf, Italian ryegrass stem and rice straw were colonised with a similar bacterial community.     

Cell density regulates prolyl 4-hydroxylase activity independent of mRNA levels

In embryonic avian tendon, cell density regulates collagen production. This control is propagated through the alpha-subunit of prolyl 4-hydroxylase where protein levels were previously shown to rise fivefold with increasing cell density. In contrast, mRNA levels are now shown not to change by both Northern and RNAse protection assays. This lack of increase contrasts with previous reports as does the mRNA length: this is 50% larger as confirmed by sequencing the 3' end. Alternative sites for cell density regulation of the enzyme could rely on its sensitivity to sulfhydryl groups. Using a fluorescent sulfhydryl probe as well as a sulfhydryl inhibitor, one observes a strong cell density response, supporting the hypothesis that cellular redox potential could alter protein stability.     

单克隆抗体及其抗感染作用的研究进展

骨髓瘤细胞和单个B细胞可融合形成杂交瘤细胞,这种细胞分离并克隆后可产生针对单一表位,且结构和功能相同的抗体,即单克隆抗体(monoclonal antibody, mAb)。单克隆抗体发展历程经历了四个阶段。其制备技术也在不断革新与发展。目前单克隆抗体技术发展日益成熟,在疾病治疗与诊断中发挥着关键的作用。单克隆抗体与天然抗体不同,具有效价高、特异性强、交叉反应少、可大量制备,靶向性高等特点。mAb可用于诊断及治疗感染性疾病、自身免疫病以及癌症等。对mAb的发展历程及mAb在抗感染性疾病中的应用进行简要阐述。     

A Comparative Study ofMiscanthus floridulus(Labill) Warb andM. transmorrisonensisHayata: Photosynthetic Gas Exchange, Leaf Characteristics and Growth in Controlled Environments

The relationship between temperature and the distribution ofMiscanthusfloridulus(Labill) Warb andM. transmorrisonensisHayata alongaltitudinal gradients in central Taiwan was examined. Responsesof biomass accumulation, leaf characteristics and photosyntheticgas exchange to growth temperature (from 10 to 30 °C) ofM.floridulusfrom an altitude of 390 m and ofM. transmorrisonensisfrom2700 m were determined. There were differences between the twospecies in above-ground biomass, CO₂uptake characteristics andleaf chlorophyll contents in response to growth temperature.The optimal temperatures for biomass accumulation were 30/25(day/night temperature) and 25/20 °C forM. floridulusandM.transmorrisonensis,respectively. Light saturated photosyntheticrates (A_max) were largest in plants grown at the optimal temperature.Growth at 15/10 and 10/10 °C compared to the optima reducedaccumulated biomass, leaf chlorophyll content and photosyntheticrate in both species with a greater reduction inM. floridulusthaninM. transmorrisonensis.We concluded that growth ofM. floridulusathigh altitude is limited by an inability to grow at temperatureslower than 15 °C, whileM. transmorrisonensisis able to growin chilling temperatures at higher altitudes.Copyright 1998Annals of Botany Company Miscanthus floridulus;M. transmorrisonensis; C₄plants; chlorophyll content; leaf growth; photosynthetic gas exchange; biomass accumulation; temperature response.