Shy-sensitive children are likely to develop adjustment problems in today's urban China as the country has evolved into an increasingly competitive, market-oriented society. The main purpose of this one-year longitudinal study was to examine the moderating effects of academic achievement on relations between shyness-sensitivity and later internalizing problems in Chinese children. A sample of 1171 school-age children (591 boys, 580 girls) in China, initially at the age of 9 years, participated in the study. Data on shyness, academic achievement, and internalizing problems were collected from multiple sources including peer evaluations, teacher ratings, self-reports, and school records. It was found that shyness positively and uniquely predicted later loneliness, depression, and teacher-rated internalizing problems, with the stability effect controlled, for low-achieving children, but not for high-achieving children. The results indicate that, consistent with the stress buffering model, academic achievement may be a buffering factor that serves to protect shy-sensitive children from developing psychological problems.

The epigenetic status of a donor nucleus has an important effect on the developmental potential of embryos produced by somatic cell nuclear transfer (SCNT). In this study, we transferred cultured rabbit cumulus cells (RCC) and fetal fibroblasts (RFF) from genetically marked rabbits (Alicia/Basilea) into metaphase II oocytes and analyzed the levels of histone H3-lysine 9-lysine 14 acetylation (acH3K9/14) in donor cells and cloned embryos. We also assessed the correlation between the histone acetylation status of donor cells and cloned embryos and their developmental potential. To test whether alteration of the histone acetylation status affects development of cloned embryos, we treated donor cells with sodium butyrate (NaBu), a histone deacetylase inhibitor. Further, we tried to improve cloning efficiency by chimeric complementation of cloned embryos with blastomeres from in vivo fertilized or parthenogenetic embryos. The levels of acH3K9/14 were higher in RCCs than in RFFs (P!0.05). Although the type of donor cells did not affect development to blastocyst, after transfer into recipients, RCC cloned embryos induced a higher initial pregnancy rate as compared to RFF cloned embryos (40 vs 20%). However, almost all pregnancies with either type of cloned embryos were lost by the middle of gestation and only one fully developed, live RCC-derived rabbit was obtained. Treatment of RFFs with NaBu significantly increased the level of acH3K9/14 and the proportion of nuclear transfer embryos developing to blastocyst (49 vs 33% with non-treated RFF, P!0.05). The distribution of acH3K9/14 in either group of cloned embryos did not resemble that in in vivo fertilized embryos suggesting that reprogramming of this epigenetic mark is aberrant in cloned rabbit embryos and cannot be corrected by treatment of donor cells with NaBu. Aggregation of embryos cloned from NaBu-treated RFFs with blastomeres from in vivo derived embryos improved development to blastocyst, but no cloned offspring were obtained. Two live cloned rabbits were produced from this donor cell type only after aggregation of cloned embryos with a parthenogenetic blastomere. Our study demonstrates that the levels of histone acetylation in donor cells and cloned embryos correlate with their developmental potential and may be a useful epigenetic mark to predict efficiency of SCNT in rabbits.

This study examined reciprocal contributions between shyness-sensitivity and social, school, and psychological adjustment in urban Chinese children. Longitudinal data were collected once a year from Grade 3 to Grade 6 (ages 9-12 years) for 1,171 children from multiple sources. Shyness-sensitivity positively contributed to social, school, and psychological difficulties over time, with the most consistent effects on peer preference and loneliness. Social and school adjustment negatively contributed to the development of shyness-sensitivity. The initial levels of shyness-sensitivity and social and school adjustment moderated the growth of each other, mainly as a resource-potentiating factor. The results indicate the significance of shyness-sensitivity for adjustment and the role of adjustment in the development of shyness-sensitivity in today's urban Chinese society.

During the first meiotic cell division (meiosis I), homologous chromosomes pair, synapse, recombine, and segregate, using highly coordinated and tightly regulated mechanisms. The synaptonemal complex (SC), a proteinaceous tripartite structure, plays an important role both as a scaffold for the close juxtaposition of homologous chromosomes and in regulating the overall process of homologous recombination. Specifically, it mediates chromosome synapsis during the lengthy prophase of meiosis I. The SC consists of two parallel lateral elements, one central element, and numerous transverse filaments. Recent genetic studies in mice have provided novel insights into the mechanisms by which the SC regulates meiosis and into the etiology of diseases such as aneuploidy. Even though the tripartite ultrastructure and meiotic functions of the SC are similar in different species, the SC components are not well-conserved at the protein sequence level. This review will focus on the identification, characterization, and functions of the synaptonemal complex proteins in mammals.

Background: In mammals the parental genomes are epigenetically reprogrammed after fertilization. This reprogramming includes a rapid demethylation of the paternal (sperm-derived) chromosomes prior to DNA replication in zygotes. Such active DNA demethylation in the zygote has been documented for several mammalian species, including mouse, rat, pig, human and cow, but questioned to occur in rabbit.