Dynamic Model for Multivariate Markers of Fecundability

Summary : Dynamic latent class models provide a flexible framework for studying biologic processes that evolve over time. Motivated by studies of markers of the fertile days of the menstrual cycle, we propose a discrete‐time dynamic latent class framework, allowing change points to depend on time, fixed predictors, and random effects. Observed data consist of multivariate categorical indicators, which change dynamically in a flexible manner according to latent class status. Given the flexibility of the framework, which incorporates semi‐parametric components using mixtures of betas, identifiability constraints are needed to define the latent classes. Such constraints are most appropriately based on the known biology of the process. The Bayesian method is developed particularly for analyzing mucus symptom data from a study of women using natural family planning.     

Preferences for masculinity in male bodies change across the menstrual cycle

In human females cyclic shifts in preference have been documented for odour and physical and behavioral male traits. Women prefer the smell of dominant males, more masculine male faces and men behaving more dominantly when at peak fertility than at other times in their menstrual cycle. Here we examine variation in preferences for body sexual dimorphism. Across two studies, both between- and within-participant, we show that women prefer greater masculinity in male bodies at times when their fertility is likely highest, in the follicular phase of their cycle. Shifts were seen when rating for a short-term but not when rating for a long-term relationship. In line with studies showing similar effects for facial sexual dimorphism, we also show that women prefer greater masculinity when they think themselves attractive than when they think themselves less attractive. These results indicate that women's preferences for sexual dimorphism in male bodies follow a similar pattern as found for sexual dimorphism and dominance in other domains and such differences in preference may serve a similar function. Cyclic preferences could influence women to select partners when most likely to become pregnant that possess traits that may be most likely to maximize their offspring's quality via attraction to masculinity or serve to help acquire investment via attraction to femininity.     

Effect of sperm numbers and time of insemination relative to ovulation on sow fertility

We examined the effect of inseminating mixed parity sows (n = 231) once with fewer sperm at different times relative to ovulation. Lactation length was 19 days and sows received an IM injection of 600 IU equine chorionic gonadotrophin (eCG) 12 h before weaning. At 80 h after eCG injection, sows received an IM injection of 5 mg porcine luteinizing hormone (pLH). Predicted time of ovulation (PTO) was 38 h after pLH injection. Sows were assigned by parity to receive a single transcervical artificial insemination (AI) at either 6 or 24 h before PTO with semen doses containing either 2.5 or 1.25 × 10⁹ sperm. A positive control group of sows (n = 49) was subject to conventional AI 24 and 6 h before PTO. Detection of estrus was performed in the presence of a boar and only sows exhibiting estrous behavior at the assigned time of AI were included in the study. Farrowing rate for sows receiving 2.5 × 10⁹ sperm at 6 h before PTO was greater than that for sows receiving 1.25 × 10⁹ sperm at 24 h before PTO (85% versus 61%, P < 0.05). All other groups were intermediate. There was no effect of time of AI or sperm numbers on subsequent litter size. These data indicate that single insemination of fewer sperm may compromise sow fertility, even when performed transcervically, if not appropriately timed relative to ovulation.     

Retransformation of a male sterile barnase line with the barstar gene as an efficient alternative method to identify male sterile–restorer combinations for heterosis breeding

We report in this study, an improved method for identifying male sterile–restorer combinations using the barnase–barstar system of pollination control for heterosis breeding in crop plants, as an alternative to the conventional line × tester cross method. In this strategy, a transgenic male sterile barnase line was retransformed with appropriate barstar constructs. Double transformants carrying both the barnase and barstar genes were identified and screened for their male fertility status. Using this strategy, 66–90% of fertile retransformants (restored events) were obtained in Brassica juncea using two different barstar constructs. Restored events were analysed for their pollen viability and copy number of the barstar gene. Around 90% of the restored events showed high pollen viability and ∼30% contained single copy integrations of the barstar gene. These observations were significantly different from those made in our earlier studies using line (barnase) × tester (barstar) crosses, wherein only two viable male sterile–restorer combinations were identified by screening 88 different cross-combinations. The retransformation strategy not only generated several independent restorers for a given male sterile line from a single transformation experiment but also identified potential restorers in the T₀ generation itself leading to significant savings in time, cost and labour. Single copy restored plants with high pollen viability were selfed to segregate male sterile (barnase) and restorer (barstar) lines in the T₁ progeny which could subsequently be diversified into appropriate combiners for heterosis breeding. This strategy will be particularly useful for crop plants where poor transformation frequencies and/or lengthy transformation protocols are a major limitation.     

A retrospective study of bitches with pyometra,medically treated with aglepristone

Pyometra is a common and life-threatening disease of intact bitches caused by hormonal influence of the uterus in combination with bacterial infection. The treatment of choice is ovariohysterectomy, but several purely medical options are available. Common drugs used for medical treatment in combination with antimicrobials are progesterone receptor blockers, prostaglandins, and dopamine agonists. The aim of this study was to evaluate long-term recovery and fertility after treatment with the progesterone receptor blocker aglepristone in bitches with pyometra. Data from 28 bitches with pyometra, admitted to the University Animal Hospital, Swedish University of Agricultural Sciences, during a 9-year period, were studied retrospectively and followed up by telephone interviews with the owners. The bitches had been treated with aglepristone at a dose of 10 mg/kg on a median of four occasions. All bitches had also been treated with antimicrobial drugs for a mean duration of 23 days, the most frequently used being enrofloxacin. Escherichia coli were the most commonly isolated bacteria from cranial vagina. The outcome was assessed for up to 6 years after treatment. The success rate, determined as restored clinically healthy status, was 75% (21/28 bitches), and the recurrence rate of disease was 48% (10/21 bitches). The mean time until recurrence was 10.5 months after the end of treatment. After treatment, 69% (9/13) of the mated bitches produced puppies. Of the seven bitches that did not have a successful treatment, six were ovariohysterectomized and one was euthanized. In conclusion, medical treatment with aglepristone in combination with antimicrobial therapy was successful in 75% of the bitches studied and the recurrence rate was 48%.     

左炔诺孕酮和炔雌醚复合物(EP-1)及组分对鼠类不育效果的研究进展

由于当前传统灭杀带来的一系列问题,鼠害不育控制逐渐受到重视。自张知彬等2004年率先报道左炔诺孕酮和炔雌醚复合物(EP-1)对野生鼠类不育效果的研究以来,国内多个研究团队对EP-1及其组分的不育效果、剂量、饵料制作、环境安全性、行为与分子机理等方面开展了大量的验证和完善研究,取得了许多重要的进展。这些结果进一步说明EP-1及组分对鼠类具有很好的不育效果,并具有两性不育、高效低量、可持续、相对环保与安全、野外投放方便、经济可行等特点。EP-1或炔雌醚毒饵的不育剂量约为10-50μg/m L(0.001%-0.005%),甚至更低;其组分在土壤和水体的半衰期约为5-16 d和小于3 d。在鼠类繁殖的早期,采取野外一次饱和投放即可有效降低全年鼠类的繁殖,效果可延续至第二年。可见,EP-1及其组分有望成为鼠害控制的一个新手段。建议今后进一步加强野外不育与跨年持续效应的验证、环境安全性评价和行为生态学机制等研究工作。     

不同干扰强度生境中啮齿动物对苦槠种子的取食和扩散

在浙江省千岛湖地区,选择了受人类活动干扰较轻、中度和严重的3个生境,采用金属片标记法研究了啮齿动物对苦槠种子的取食和扩散.结果表明:在研究点捕获的取食种子的啮齿动物为针毛鼠( Niviventer fulvescens),尽管捕获的数量少,但种子被取食和扩散的速率很快,3个样地内的种子均在2d内被取食或扩散完毕;中等干扰强度的生境中,被就地取食的种子最多,占鉴别种子总数的37.8%.种子扩散距离大多<5m,最大扩散距离为24.76m,3个样地种子扩散均符合负指数分布,且样地间没有显著差异;饱满种子与虫蛀种子被就地取食与搬运后取食的命运没有显著差异,但饱满种子的最大扩散距离均显著大于虫蛀种子(P<0.05),除中等干扰样地中饱满种子与虫蛀种子平均扩散距离没有显著差异外,其余2个样地中饱满种子的平均扩散距离均显著大于虫蛀种子,显示啮齿动物对饱满种子与虫蛀种子有一定的区分能力.     

Diversity in fertility potential and organo-sulphur compounds among garlics from Central Asia

Extending the collection of garlic (Allium sativum L.) accessions is an important means that is available for broadening the genetic variability of this cultivated plant, with regard to yield, quality, and tolerance to biotic and abiotic traits; it is also an important means for restoring fertility and flowering. In the framework of the EU project Garlic and Health, 120 garlic accessions were collected in Central Asia – the main centre of garlic diversity. Plants were documented and thereafter maintained in field collections in both Israel and The Netherlands. The collection was evaluated for biological and economic traits. Garlic clones vary in most vegetative characteristics (leaf number, bulb size and structure), as well as in floral scape elongation and inflorescence development. A clear distinction was made between incomplete bolting and bolting populations; most of the accessions in the latter populations produced flowers with fertile pollen and receptive stigma. Wide variations were recorded with regard to differentiation of topsets, their size, number and rapidity of development. Furthermore, significant variation in organo-sulphur compounds (alliin, isoalliin, allicin and related dipeptides) was found within garlic collections and between plants grown under differing environmental conditions. Genetic fingerprinting by means of AFLP markers revealed three distinct groups within this collection, differing also in flowering ability and organo-S content.     

A Tropical Freshwater Wetland: I. Structure,Growth, and Regeneration

Forested wetlands dominated by Terminalia carolinensis are endemic to Micronesia but common only on the island of Kosrae, Federated States of Micronesia. On Kosrae, these forests occur on Nansepsep, Inkosr, and Sonahnpil soil types, which differ in degree of flooding and soil saturation. We compared forest structure, growth, nutrition, and regeneration on two sites each on Nansepsep and Inkosr soils and one site on the much less common Sonahnpil soil type. Terminalia tree sizes were similar on all three soil types, but forests differed in total basal area, species of smaller trees, and total plant species diversity. Terminalia regeneration was found only on the Inkosr soil type, which had the highest water table levels. Other Terminalia species are relatively light demanding, and T. carolinensis exhibited similar characteristics. It is therefore likely that Terminalia requires periodic, but perhaps naturally rare, stand-replacing disturbances (e.g., typhoons) in order to maintain its dominance, except on the wettest sites, where competition from other species is reduced. Terminalia swamps in the Nansepsep soil type appeared to be at the greatest risk of conversion to other uses, but swamps on all three types may face greater pressure as Kosrae's population increases and the island's infrastructure becomes more developed.