外源性VEGF及Ang-1对大鼠CNV的作用及机制探讨

目的:研究细胞因子VEGF,Ang-1对大鼠脉络膜新生血管的形成、分化以及成熟过程的影响及机制。方法:采用激光光凝诱导建立大鼠CNV动物模型后,分别在不同时期玻璃体腔注射VEGF,Ang-1,通过其眼底荧光造影与病理切片的变化观察上述因子的作用。结果:血管生成素-1组比对照组晚期渗漏明显减少,VEGF组较对照组晚期渗漏明显增加;组织病理切片显示实验组瘢痕形成,VEGF组和对照组可见肉芽组织。结论:血管生成素-1能有效抑制脉络膜新生血管的生成,促进新生的脉络膜新生血管成熟,促进瘢痕形成。

Highly efficient differentiation of human ES cells and iPS cells into mature pancreatic insulin-producing cells

Human pluripotent stem cells represent a potentially unlimited source of functional pancreatic endocrine lineage cells. Here we report a highly efficient approach to induce human embryonic stem （ES） cells and induced pluripo- tent stem （iPS） cells to differentiate into mature insulin-producing cells in a chemical-defined culture system. The differentiated human ES cells obtained by this approach comprised nearly 25% insulin-positive cells as assayed by flow cytometry analysis, which released insulin/C-peptide in response to glucose stimuli in a manner comparable to that of adult human islets. Most of these insulin-producing cells co-expressed mature β cell-specific markers such as NKX6-1 and PDX1, indicating a similar gene expression pattern to adult islet β cells in vivo. In this study, we also demonstrated that EGF facilitates the expansion of PDXl-positive pancreatic progenitors. Moreover, our protocol also succeeded in efficiently inducing human iPS cells to differentiate into insuIin-producing ceils. Therefore, this work not only provides a new model to study the mechanism of human pancreatic specialization and maturation in vitro, but also enhances the possibility of utilizing patient-specific iPS cells for the treatment of diabetes.

Physicochemical Properties of Banana Flour as Influenced by Variety and Stage of Ripeness： Multivariate Statistical Analysis

Physicochemical properties of banana flour （BF） were studied in two varieties （Cavendish and Dream） and two stages of ripeness （green and ripe）. BF＇s were analyzed for pH, total soluble solids （TSS）, water holding capacity （WHC） and oil holding capacity （OHC） at 40℃, 60 ℃ and 80 ℃, color values L＊, a＊ and b＊, back extrusion force and viscosity. Physicochemical data were analyzed by Multivariate Analysis of Variance, discriminant analysis and cluster analysis. All statistical analyses showed that physicochemical properties of BF prepared from different variety and stage of ripeness were different from each other. Viscosity, WHC40, WHC60 and TSS were recommended methods for discrimination between banana flour prepared from the two varieties, whilst viscosity, WHC60 and WHC80 were suggested for differentiation of banana flour prepared using green and ripe banana.

Geochemistry of solvable organic matter from source rocks in Shangkuli Formation of Labudalin Basin

A suit of lacustrine source rocks are developed in volcanic deposits in the Shangkuli Formation of the Cretaceous. However, it is poor to understand the characteristics of source rocks due to the low degree of exploration, thus the exploration is severely constrained in this area. Based on the geochemical analysis, the analytic technique of GC and GC-MS, combined with the characteristics of solvable organic matter and biomarkers of the source rocks, the authors discussed the depositional environment, the derivation of the matrix and the maturity characteristics of the organic material of the Shangkuli Formation in Cretaceous. The results show that the organic matter mainly belongs to type Ⅱ1 kerogen, whose abundance is relatively high; it was formed in reductive surrounding where was deep-lake; the hydrocarbon is characterized by mixed-source of organic matter. The thermal evolution of source rocks had reached maturation stage.

Reprogramming mature terminally differentiated adipocytes to induced pluripotent stem cells

Mature adipocytes are terminally differentiated somatic cells. Here, we report the successful generation of induced pluripotent stem （iPS） cells from mouse mature adipocytes by forced expression of six transcription factors （Oct4, Sox2, c-Myc, Klf4, Rarγ, and Lrh1） with a piggyBac transposon-based strategy. The resulting iPS cells were pluripotent as evidenced by the fact that they stained positive for alkaline phosphatase, expressed high levels of key pluripotency markers including Oct4, Nanog, and SSEA1, and remained pluripotent on a 2i media. In vitro differen- tiation of the iPS cells showed that the cell derivatives of all three germ layers could be readily obtained through forma- tion of embryoid bodies. Most importantly, these adipocyte- derived iPS cells were capable of producing chimera with high frequencies when reintroduced into early-stage em- bryos and transmitted through the germ line. This study demonstrates that the new six-factor reprogramming tech- nology facilitates the reset of the terminally differentiated adipocytes to the ground state of pluripotency, enabling us to fully explore the potential of mature adipocytes as a viable cell source for regenerative medicine.

Fruit fly courtship： The female perspective

Research on fruit fly courtship has mostly focused on males＇ behavioral repertoire whereas females have been as- sumed to respond by either rejecting or accepting males. In many fruit fly species including Drosophila melanogaster, however, mating typically follows an extended period of courtship, which provides ample opportunities for females to inform males about their likelihood of mating. Our experiments indeed revealed that sexually immature females in both D. melanogasterand D. si- mulans showed responses to conspecific males that were distinct from those of sexually mature females. Furthermore, females＇ responses to conspecifie males were different from their responses to heterospecific males. Our data indicate that females＇ beha- vioral repertoire early in courtship can inform males about their probability of mating if they persist in courting. We hypothesize （i） that males can rely on behavioral feedback from females for optimally allocating their courtship efforts towards distinct female classes, （ii） that males may learn to modulate their courtship behavior based on specific feedback from females, and （iii） that fe- males may learn to alter their behavior towards distinct types of males in order to elicit the desired male response. Overall, we suggest that, although little explored, female behavior determines the dynamics of courtship and mating and can thus influence sexual selection and incipient speciation .

Protect chromosomes from end-to-end fusion during meiotic bouquet

Meiosis generates gametes with half the parental chromosome complements,and thus is crucial for successful sexual reproduction.During meiotic prophase I,a series of specialized events occur to ensure correct paternal and maternal homologous chromosomes（homologs）segregation during anaphase I.They include recognition,alignment,pairing and synapsis of the homologs and meiotic recombination which provides a link between homologs.

The effect of volatile components in oil on evolutionary character- istics of diamondoids during oil thermal pyrolysis

On the basis of the results of simulation experiments, now we better understand the contribution of high carbon number hydrocarbons to diamondoid generation during thermal pyrolysis of crude oil and its sub-fractions(saturated, aromatic, resin, and asphalene fractions). However, little is known about the effect of volatile components in oil on diamondoid generation and diamondoid indices due to the lack of attention to these components in experiments. In this study, the effect of volatile components in oil on diamondoid generation and maturity indices was investigated by the pyrolysis simulation experiments on a normal crude oil from the HD23 well of the Tarim Basin and its residual oil after artificial volatilization, combined with quantitative analysis of diamondoids. The results indicate that the volatile components(≤n C12) in oil have an obvious contribution to the generation of adamantanes, which occurs mainly in the early stage of oil cracking(Easy Ro<1.0%), and influences the variations in maturity indices of adamantanes; but they have no obvious effect on the generation and maturity indices of diamantanes. Therefore, some secondary alterations e.g., migration, gas washing, and biodegradation, which may result in the loss of light hydrocarbons in oil under actual geological conditions, could affect the identification of adamantanes generated during the late-stage cracking of crude oil, and further influence the practical application of adamantane indices.