Transgenerational Effects of Di(2-Ethylhexyl) Phthalate on Anogenital Distance,Sperm Functions and DNA Methylation in Rat Offspring

Di(2-ethylhexyl) phthalate (DEHP) is widely used as a plasticizer in the manufacture of polyvinylchloride plastics and has been associated with concerns regarding male reproductive toxicity. In this study, we hypothesized that maternal exposure to DEHP induces transgenerational inheritance of adult-onset adverse reproductive outcomes through the male germline in the F1, F2, and F3 generations of male offspring. Pregnant rats were treated with 5 or 500 mg of DEHP/kg/day through gavage from gestation day 0 to birth. The offspring body weight, anogenital distance (AGD), anogenital index (AGI), sperm count, motility, and DNA fragmentation index (DFI) were measured for all generations. Methyl-CpG binding domain sequencing was performed to analyze sperm DNA methylation status in the F3. DEHP exposure at 500 mg/kg affected AGD, AGI, sperm count, mean DFI, and %DFI in the F1; AGD, sperm count, and mean DFI in the F2; and AGD, AGI, mean DFI, and %DFI in the F3. DEHP exposure at 5 mg/kg affected AGD, AGI, sperm count, and %DFI in the F1; sperm count in the F2; and AGD and AGI in F3. Compared with the control group, 15 and 45 differentially hypermethylated genes were identified in the groups administered 5 mg/kg and 500 mg/kg DEHP, respectively. Moreover, 130 and 6 differentially hypomethylated genes were observed in the groups administered 5 mg/kg and 500 mg/kg DEHP. Overall, these results demonstrated that prenatal exposure to DEHP caused transgenerational epigenetic effects, which may explain the observed phenotypic changes in the male reproductive system.     

云杉八齿小蠹Ips typographus L.虚拟模型构建方法研究

本文以云杉八齿小蠹Ips typographus Linnaeus为例,经标本选取,观察虫体整体形态,绘制整体结构草图,电子显微镜观察局部、得到局部数字图像,分别建立虫体每一部分的高精度细节。把模型每部分拼装在一起组成整体模型,构建出了云杉八齿小蠹三维虚拟昆虫数字化模型。     

Sperm metabolism is altered during storage by female insects: evidence from two-photon autofluorescence lifetime measurements in bedbugs

We explore the possibility of characterizing sperm cells without the need to stain them using spectral and fluorescence lifetime analyses after multi-photon excitation in an insect model. The autofluorescence emission spectrum of sperm of the common bedbug, Cimex lectularius, was consistent with the presence of flavins and NAD(P)H. The mean fluorescence lifetimes showed smaller variation in sperm extracted from the male (tau m, τ_m = 1.54–1.84 ns) than in that extracted from the female sperm storage organ (tau m, τ_m = 1.26–2.00 ns). The fluorescence lifetime histograms revealed four peaks. These peaks (0.18, 0.92, 2.50 and 3.80 ns) suggest the presence of NAD(P)H and flavins and show that sperm metabolism can be characterized using fluorescence lifetime imaging. The difference in fluorescence lifetime variation between the sexes is consistent with the notion that female animals alter the metabolism of sperm cells during storage. It is not consistent, however, with the idea that sperm metabolism represents a sexually selected character that provides females with information about the male genotype.     

Termites live in a material world: exploration of their ability to differentiate between food sources.

Drywood termites are able to assess wood size using vibratory signals, although the exact mechanism behind this assessment ability is not known. Important vibratory characteristics such as the modal frequencies of a wooden block depend on its geometry and boundary conditions; however, they are also dependent on the material characteristics of the block, such as mass, density and internal damping. We report here on choice experiments that tested the ability of the drywood termite Cryptotermes secundus to assess wooden block size using a solid wooden block paired with a composite block, the latter made of either wood and aluminium or wood and rubber. Each composite block was constructed to match mass or low-frequency vibratory modes (i.e. fundamental frequency) of the solid wooden block. The termites always chose the blocks with more wood; they moved to the solid wooden blocks usually within a day and then tunnelled further into the solid wooden block by the end of the experiment. Termites offered composite blocks of wood and rubber matched for mass were the slowest to show a preference for the solid wooden block and this preference was the least definitive of any treatment, which indicated that mass and/or damping may play a role in food assessment. This result clearly shows that the termites were not fooled by composite blocks matched for mass or frequency, which implies that they probably employ more than a single simple measure in their food assessment strategy. This implies a degree of sophistication in their ability to assess their environment hitherto unknown. The potential importance of alternative features in the vibrational signals is discussed.     

Cyclamate intake and cyclohexylamine excretion are not related to male fertility in humans

Cyclamate and its metabolite cyclohexylamine affect male fertility in high dose animal studies, but this affect has not been investigated in epidemiological studies. This paper reports the first epidemiological study designed to investigate the possibility of a relationship between cyclamate and cyclohexylamine and male fertility in humans, in which 405 cases of clinically defined infertility in men and 379 controls were surveyed. Semen evaluation, urine analysis for cyclamate and cyclohexylamine and dietary questionnaires were compared between cases and controls. No evidence was found of a significant association between cyclamate intake and male infertility; neither high cyclamate nor high cyclohexylamine excretion were associated with elevated risk. The lack of association remained after adjusting by age, area of residence, education, total energy intake and other variables. No significant correlations were observed between cyclamate intake, metabolism or excretion, and sperm count and motility. The results demonstrate no effect of cyclamate or cyclohexylamine on male fertility at the present levels of cyclamate consumption.     

Absence makes the adaptations grow fonder: Proportion of time apart from partner, male sexual psychology, and sperm competition in humans (Homo sapiens).

Sperm competition occurs when the sperm of multiple males concurrently occupy the reproductive tract of a female and compete to fertilize an egg. We used a questionnaire to investigate psychological responses to the risk of sperm competition for 237 men in committed, sexual relationships. As predicted, a man who spends a greater (relative to a man who spends a lesser) proportion of time apart from his partner since the couple's last copulation reported (a) greater sexual interest in his partner, (b) greater distress in response to his partner's sexual rejection, and (c) greater sexual persistence in response to his partner's sexual rejection. All effects were independent of total time since the couple's last copulation and the man's relationship satisfaction. Discussion addresses limitations of the current research and situates the current results within the broader comparative literature on adaptation to sperm competition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

采用注视控制器实现复杂运动的仿真

注视控制器是3DS MAX软件的众多控件之一，它能使多个物体彼此间产生运动约束。通过使用注视控制器功能，笔者成功制作出八足爬壁式仿生机械昆虫的运动场景动画，并使该仿生机械昆虫各足的行走动作符合机械零件作平面复杂运动时所应遵守的正确运动规律。由此证明，3DS MAX软件注视控制器对正确模拟特殊机械装置的复杂运动可产生极大作用。     

The measurement of gastric motor function and transit in man by echo planar magnetic resonance imaging

Echo-planar imaging (EPI) can be used to produce snapshot images of the human stomach and antro-pyloro-duodenal segment in real time as an alternative technique to intubation and exposure to ionizing radiation. The method has been further developed to monitor simultaneous gastric motility and gastric emptying of liquid and solid meals. The model has been utilized to study the effects of pharmacological agents on gastric function.Eight normal subjects were imaged in a 0.5-T superconducting magnet for up to 6 h following ingestion of 800 ml tap water, followed by 500 ml porridge test meal + 500 ml tap water. A rapid multislice technique was adopted to image adjacent transverse slices (10 mm thick) through the gastric region. In addition, three subjects were orally dosed with 20 mg of the prokinetic agent Cisapride. Gastric volumes for each slice were calculated and summed to produce a measure of total gastric volume and gastric emptying. Contractile activity at the level of the antro-pyloric segment was detected using sequential 128 ms images at 3 s intervals. Alternate measurements of gastric volume and motility were made for the duration of the study.Gastric emptyingT _1/2's (times to empty 50% of the gastric contents) of 12.9 min for water and 116 min for porridge were in agreement with results obtained by the traditional techniques of gamma scintigraphy and impedance imaging. The frequency of gastric contractions increased from 2.4 contractions per minute (cpm) to 3.2 cpm following water and from 2.9 to 3.2 cpm following porridge. The prokinetic effect of enhanced coordination of antroduodenal contractions was also observed. These studies have demonstrated that EPI can be used to detect and image gastroduodenal function in man, totally noninvasively, and can be used to study the effects of drugs acting on the gastrointestinal tract.     

胃动力信息采集与分析系统设计

本文设计了一套提取胃电和胃阻抗信号的胃动力信息采集与分析系统，该系统由采集系统和分析系统两部分构成。前者以单片机（ADuC834）为核心部件，实现了胃电和生物阻抗信号的同步采集和数据传输。后者对提取的阻抗信号和胃电信号运用小波多分辨分析处理，利用小波变换将胃阻抗信号从呼吸和血流信号中分离。系统可以应用于分析功能性消化不良患者胃动力的电过程和机械过程。     

Effect of temperature on recombinant protein production using the Bm5/Bm5.NPV expression system

A series of experiments have been conducted using a recombinant baculovirus/insect cell expression system (Bm5/Bm5.NPV.CAT) to establish the optimum temperature for both cell growth and virus infection. Bm5 cell growth was found to be limited at temperatures below 22°C and ceased completely at temperatures above 34°C. In the range between 24 and 28°C, final cell densities always reached 96% of the highest achievable viable cell density. The shortest population doubling time was obtained at 28°C. Overall, a consistent increase in metabolism with increasing temperatures was observed. During the infection/viral replication phase, an increase in the temperature from 25 to 31°C resulted in a faster decrease in viable cell density and an earlier production of chloramphenicol acetyltransferase (CAT). Furthermore, protein yield at temperatures above 28°C was significantly reduced. Overall, the best temperature for the infection phase for the Bm5/Bm5.NPV expression system was found to be 25°C when the cells are cultured in serum free media.