Effects of egg aging on in vitro fertilization and first cleavage division in the hamster

The postovulatory fertile life of mammalian eggs is remarkably short (approximately 6-36h). Anomalies of embryogenesis may result from fertilization of aged, defective eggs. Attempts to study this problem using whole-animal models are complicated by chances in the natural milieu of the gametes. In the present study, postovulatory hamster eggs were allowed to agein vivo then fertilized in vitro. Cumulus-intact eggs recovered from superovulated hamsters either 2 or 9 h after the estiated time of ovulation (12 h postHCG) were incubated for 4 h with preincubated sperm suspentions in a modified Tyrode's solution devised for in vitro fertilization. Eggs were either fixed or cultured for another 20h in fresh medium to allow cleavage to occur, then examined by light microscopy (phase and interference-contrast). No significant difference was found in the ablities of fresh and aged eggs to be penetrated by spermatozoa (94% vs 90%, respectively; 8 replicated experiments), but only 59% of penetrated aged eggs were found to undergo morphologically normally fertilization (2 polar bodies, 2 prounclei) compared with 75% of fresh eggs (difference significant, P< 0.01). About 13% of eggs were polyspermic in both categories. The most common anomaly in aged fertilied egges was failure to extrude the second polor body (23% off eggs vs 8% of fresh eggs, P < 0.01). Only 21% of aged eggs underwent first cleavaage, and only 74% of these appeared morphologically normal, compared with value of 68% and 98%, respectively, for fresh eggs. These data show that in the hamster, abnormal fertilization and cleavage failure can, in part, be directly attributed to postovulatory deterioration of eggs. We also infer that the apparently very short penetrable life of hamster eggs in vivo shown by previous investigators is an indirect effect of postovulatory changes in the female reproductive tract that are unfavorable for sperm-egg interactions.     

Maternal diabetes and congenital anomalies in South Australia 1986-2000: a population-based cohort study

BACKGROUND: This study examined the risk of congenital anomalies in infants born in South Australia to women with maternal diabetes in a population-based cohort study of births over a 15-year period, 1986-2000. Differences in the reporting, recording, and diagnosis of pre-existing diabetes mellitus, gestational diabetes mellitus, and impaired glucose tolerance make comparisons between studies difficult. In order to compare published research, details of research methods and analytic approaches are required to understand the potential confounding, bias, and effect modification that may occur. METHODS: Data on congenital anomalies from the South Australian Birth Defects Register were linked to birth data from the Pregnancy Outcome Statistics Unit of the South Australian Department of Health. This enabled information on congenital anomalies to be linked to pregnancy details, including diabetes status. RESULTS: Between 1986 and 2000, the prevalence of congenital anomalies in the infants of mothers with pre-existing diabetes mellitus, gestational diabetes mellitus, or impaired glucose tolerance was significantly higher than in the total population; relative risk = 2.01 (1.66-2.43) and 1.19 (1.08-1.31), respectively. This increased prevalence was not modified by adjustments for maternal age, ethnicity, or other demographic factors, nor did the rate change over the 15 years of the study period. CONCLUSIONS: The prevalence of congenital anomalies was found to be significantly higher in the infants of mothers with maternal diabetes. Larger population-based studies are needed to determine which anomalies are involved and how their occurrence can be reduced.     

中国兰科石豆兰属（Bulbophyllum）二新种

对兰科（Orchidaceae）石豆兰属（Bulbophyllum）二新种,副萼石豆兰（B.malipoense Z.J.Liu,L.J.Chen＆W.H.Rao）和小副萼石豆兰（B.minor Z.J.Liu,L.J.Chen＆W.H.Rao）作了描述和绘图。该二新种属于石豆兰属副萼组（Bulbophyllumsection BisetaJ.J.Verm.ex N.Pearce,P.J.Cribb＆J.Renz）,与该组的刺萼石豆兰（B.bisetum Lindl.）相似,区别在于两新种的叶片先端二裂和唇瓣无毛。小副萼石豆兰与副萼石豆兰的区别在于假鳞茎椭圆球形;叶片卵状椭圆形,长1.2～2 cm;侧副萼片较短,长约1 mm;中副萼片几乎与两侧萼片边缘合生。     

Seven-week embryo with gastroschisis, multiple anomalies, and physiologic hernia suggests early onset of gastroschisis

Gastroschisis is an increasingly common birth defect involving the development of the ventral body wall. Extrusion of the bowel is usually paraumbilical, usually right sided, and associated anomalies are less common than in omphalocele. Recently, hypotheses regarding the timing of the typical gastroschisis defect have come into question. Unlike previous theories, Feldkamp et al. (2007) has postulated that gastroschisis occurs much earlier in development, before abdominal wall closure, which is completed by about 35 days postconception. We present a case of a spontaneously aborted dysmorphic embryo which exhibits features of the normal physiologic herniation of the midgut as well as gastrochisis. The co-existence of the abdominal wall defect in this abnormal embryo with the physiologic hernia supports the early development of this defect and also illustrates the causal heterogeneity of gastroschisis.     

Engineering triacylglycerol accumulation in duckweed (Lemna japonica)

Duckweeds are amongst the fastest growing of higher plants, making them attractive high-biomass targets for biofuel feedstock production. Their fronds have high rates of fatty acid synthesis to meet the demand for new membranes, but triacylglycerols (TAG) only accumulate to very low levels. Here we report on the engineering of Lemna japonica for the synthesis and accumulation of TAG in its fronds. This was achieved by expression of an estradiol-inducible cyan fluorescent protein-Arabidopsis WRINKLED1 fusion protein (CFP-AtWRI1), strong constitutive expression of a mouse diacylglycerol:acyl-CoA acyltransferase2 (MmDGAT), and a sesame oleosin variant (SiOLE(*)). Individual expression of each gene increased TAG accumulation by 1- to 7-fold relative to controls, while expression of pairs of these genes increased TAG by 7- to 45-fold. In uninduced transgenics containing all three genes, TAG accumulation increased by 45-fold to 3.6% of dry weight (DW) without severely impacting growth, and by 108-fold to 8.7% of DW after incubation on medium containing 100 μm estradiol for 4 days. TAG accumulation was accompanied by an increase in total fatty acids of up to three-fold to approximately 15% of DW. Lipid droplets from fronds of all transgenic lines were visible by confocal microscopy of BODIPY-stained fronds. At a conservative 12 tonnes (dry matter) per acre and 10% (DW) TAG, duckweed could produce 350 gallons of oil/acre/year, approximately seven-fold the yield of soybean, and similar to that of oil palm. These findings provide the foundation for optimizing TAG accumulation in duckweed and present a new opportunity for producing biofuels and lipidic bioproducts.     

Improving the accuracy of population size estimates for burrow‐nesting seabirds

Seabird numbers can change rapidly as a result of environmental processes, both natural and anthropogenic. Informed management and conservation of seabirds requires accurate and precise monitoring of population size. However, for burrow‐nesting species this is rarely achieved due to spatial and temporal heterogeneity in burrow occupancy. Here, we describe a novel method for deriving more accurate population size estimates that employs mark‐recapture methods to correct for unknown variation in nest occupancy throughout a breeding season. We apply it to estimate breeding numbers of a colonial, burrowing seabird, the Little Penguin Eudyptula minor, on the Summerland Peninsula, Phillip Island, Australia. Estimates of active burrow numbers during the September 2008 to February 2009 breeding season were adjusted to numbers of breeding birds based on burrow occupation and modelled population demographics at six, fortnightly monitored reference sites. The population was estimated to be 26 100 (95% CI: 21 100–31 100) and 28 400 (23 800–33 000) breeding Penguins in two temporally separated surveys within one breeding season. We demonstrate using simulation that the method is robust to variation in burrow occupancy throughout the breeding season, providing consistent and more accurate estimates of population size. The advantage of using the corrected method is that confidence intervals will include the true population size. Confidence limits widened as burrow occupancy declined, reflecting the increased uncertainty as larger adjustments for low burrow occupancy were required. In contrast, the uncorrected method that uses burrow occupancy alone as a measure of breeding numbers was inconsistent and significantly underestimated population size across much of the breeding season. Although requiring considerably more survey effort, the corrected approach provides a more accurate means for monitoring population changes in colonially breeding animals while collecting demographic data that can help diagnose the drivers of population change.     

武汉地区大山雀（Parus major minor）对major与minor亚种组鸣唱回放的差别反应

分析鸟类鸣声能为研究鸟类系统学和生物地理学提供重要信息。鸟类鸣声的地理变异能影响鸟类的性选择,进而导致不同地理种群间的生殖隔离,从而促进地方种群(或亚种)的分化,乃至新种的形成。在鸟类系统学研究中,鸣声回放实验是研究物种分化并衡量分类地位的一项重要研究手段。本实验以武汉地区大山雀(Parus major minor,隶属于minor亚种组)为实验对象进行鸣唱回放实验,观测其对来自欧亚大陆西部及北部各地的major亚种组和来自我国各地的minor亚种组大山雀鸣唱回放的反应,探讨实验对象能否区分来自上述两个不同亚种组的鸣唱,从而推断两亚种组之间是否存在足以导致识别障碍的鸣声分化,以致产生行为上的生殖隔离。本实验共测试了24只雄性大山雀,每个亚种组的鸣唱各回放给12只个体,通过记录不同行为反应指标来衡量每只受试个体的反应程度。统计分析结果显示,受试大山雀对major和minor亚种组鸣唱的反应有显著差异,对同为minor亚种组的鸣唱反应程度激烈,而对major亚种组鸣唱的反应微弱甚至大多无反应。由此认为,大山雀major和minor亚种组之间存在显著的鸣声分化,已达到能形成配对前生殖隔离的程度,从而一定程度上支持将大山雀拆分成不同种的说法。     

Bioremediation of an Iron-Rich Mine Effluent by Lemna minor

Contamination of water resources by mine effluents is a serious environmental problem. In a old coal mine, in the north of Portugal (São Pedro da Cova, Gondomar), forty years after the activity has ended, a neutral mine drainage, rich in iron (FE) it stills being produced and it is continuously released in local streams (Ribeiro de Murta e Rio Ferreira) and in surrounding lands.The species Lemna minor has been shown to be a good model for ecotoxicological studies and it also has the capacity to bioaccumulate metals.The work aimed test the potential of the species L. minor to remediate this mine effluent, through the bioaccumulation of Fe, under greenhouse experiments and, at the same time, evaluate the time required to the maximum removal of Fe. The results have shown that L. minor was able to grow and develop in the Fe-rich effluent and bioaccumulating this element. Throughout the 21 days of testing it was found that there was a meaningful increase in the biomass of L. minor both in the contaminated and in the non-contaminated waters. It was also found that bioaccumulation of Fe (iron) occurred mainly during the first 7 days of testing. It was found that L. minor has potential for the bioremediation of effluents rich in iron.