Meta-analyses identify 13 loci associated with age at menopause and highlight DNA repair and immune pathways

To newly identify loci for age at natural menopause, we carried out a meta-analysis of 22 genome-wide association studies (GWAS) in 38,968 women of European descent, with replication in up to 14,435 women. In addition to four known loci, we identified 13 loci newly associated with age at natural menopause (at P < 5 × 10(-8)). Candidate genes located at these newly associated loci include genes implicated in DNA repair (EXO1, HELQ, UIMC1, FAM175A, FANCI, TLK1, POLG and PRIM1) and immune function (IL11, NLRP11 and PRRC2A (also known as BAT2)). Gene-set enrichment pathway analyses using the full GWAS data set identified exoDNase, NF-κB signaling and mitochondrial dysfunction as biological processes related to timing of menopause.     

Computer modeling of high-pressure leaching process of nickel laterite by design of experiments and neural networks

Due to the complex chemical composition of nickel ores, the requests for the decrease of production costs, and the increase of nickel extraction in the existing depletion of high-grade sulfide ores around the world, computer modeling of nickel ore leaching process became a need and a challenge. In this paper, the design of experiments (DOE) theory was used to determine the optimal experimental design plan matrix based on the D optimality criterion. In the high-pressure sulfuric acid leaching (HPSAL) process for nickel laterite in "Rudjinci" ore in Serbia, the temperature, the sulfuric acid to ore ratio, the stirring speed, and the leaching time as the predictor variables, and the degree of nickel extraction as the response have been considered. To model the process, the multiple linear regression (MLR) and response surface method (RSM), together with the two-level and four-factor full factorial central composite design (CCD) plan, were used. The proposed regression models have not been proven adequate. Therefore, the artificial neural network (ANN) approach with the same experimental plan was used in order to reduce operational costs, give a better modeling accuracy, and provide a more successful process optimization. The model is based on the multi-layer neural networks with the back-propagation (BP) learning algorithm and the bipolar sigmoid activation function.     

Comparative and demographic analysis of orang-utan genomes

'Orang-utan' is derived from a Malay term meaning 'man of the forest' and aptly describes the southeast Asian great apes native to Sumatra and Borneo. The orang-utan species, Pongo abelii (Sumatran) and Pongo pygmaeus (Bornean), are the most phylogenetically distant great apes from humans, thereby providing an informative perspective on hominid evolution. Here we present a Sumatran orang-utan draft genome assembly and short read sequence data from five Sumatran and five Bornean orang-utan genomes. Our analyses reveal that, compared to other primates, the orang-utan genome has many unique features. Structural evolution of the orang-utan genome has proceeded much more slowly than other great apes, evidenced by fewer rearrangements, less segmental duplication, a lower rate of gene family turnover and surprisingly quiescent Alu repeats, which have played a major role in restructuring other primate genomes. We also describe a primate polymorphic neocentromere, found in both Pongo species, emphasizing the gradual evolution of orang-utan genome structure. Orang-utans have extremely low energy usage for a eutherian mammal, far lower than their hominid relatives. Adding their genome to the repertoire of sequenced primates illuminates new signals of positive selection in several pathways including glycolipid metabolism. From the population perspective, both Pongo species are deeply diverse; however, Sumatran individuals possess greater diversity than their Bornean counterparts, and more species-specific variation. Our estimate of Bornean/Sumatran speciation time, 400,000?years ago, is more recent than most previous studies and underscores the complexity of the orang-utan speciation process. Despite a smaller modern census population size, the Sumatran effective population size (N(e)) expanded exponentially relative to the ancestral N(e) after the split, while Bornean N(e) declined over the same period. Overall, the resources and analyses presented here offer new opportunities in evolutionary genomics, insights into hominid biology, and an extensive database of variation for conservation efforts.     

Maturation of Osteoblast-Like Saos-2 on Hydroxyapatite Ceramics

Hydroxyapatite ceramics (.HA) has been proved to be excellent in biocompatibility and bioactivity.However, limited information is available concerning how HA ceramics affects the maturation of es-tcoblasts in molecular biological level /n v/tro. This study examines the mRNA expression and protein production of hone-related genes in estcoblast-like cell line(Saos-2) cultured on HA disks. Saos-2 cells are seeded onto the substrates and cultured for 18 days. Harvested cells are tested for the cell growth rate, expression of mRNAs for esteocalcin and alkaline phosphatase, and protein production of bone sialo-protein and esteocalcin. MTS assay shows that cell proliferates well on HA ceramic substrate. After 9d,bone sialoprotein and esteocalcin protein production in SAPS-2 increases more on HA surfaces than on control material. As bone sialoprotein and esteocalcin are the genes to be highly expressed at the late stage of estcoblast differentiation, this study reveals that after long time culture in HA, HA can induce Saos-2 maturation. The behavior of Saos-2 on HA surfaces revealed in this study provides valuable infor-mation for the understanding of the biocompatibility and bioactivity of HA ceramics.     

羟基磷灰石陶瓷诱导成骨细胞的研究

通过定量检测在羟基磷灰石(HA)表面生长的成骨细胞骨涎蛋白和骨钙蛋白的表达,研究了羟基磷灰石陶瓷对成骨细胞的影响．研究结果表明,随着成骨细胞培养时间的延长,在羟基磷灰石表面生长的成骨细胞骨钙蛋白和骨涎蛋白的表达量相对于对照组有显著增加．由于骨钙蛋白和骨涎蛋白是成骨细胞分化晚期高度表达的两种标志性蛋白质,因此其表达量的显著提高意味着羟基磷灰石陶瓷可以诱导成骨细胞的成熟。这一结果可进一步为理解HA陶瓷的生物相容性和生物活性提供分子生物学依据。     

Dual antiglioma action of metformin: cell cycle arrest and mitochondria-dependent apoptosis

The present study reports for the first time a dual antiglioma effect of the well-known antidiabetic drug metformin. In low-density cultures of the C6 rat glioma cell line, metformin blocked the cell cycle progression in G₀/G₁ phase without inducing significant cell death. In confluent C6 cultures, on the other hand, metformin caused massive induction of caspase-dependent apoptosis associated with c-Jun N-terminal kinase (JNK) activation, mitochondrial depolarization and oxidative stress. Metformin-triggered apoptosis was completely prevented by agents that block mitochondrial permeability transition (cyclosporin A) and oxygen radical production (N-acetylcisteine), while the inhibitors of JNK activation (SP600125) or glycolysis (sodium fluoride, iodoacetate) provided partial protection. The antiglioma effect of metformin was reduced by compound C, an inhibitor of AMP-activated protein kinase (AMPK), and was mimicked by the AMPK agonist AICAR. Similar effects were observed in the human glioma cell line U251, while rat primary astrocytes were completely resistant to the antiproliferative and proapoptotic action of metformin. Received 14 February 2007; received after revision 26 March 2007; accepted 3 April 2007