No evidence of mineralization abnormalities in iliac bone of premenopausal women with type 2 diabetes mellitus

Objectives:Patients with type-2 diabetes mellitus (T2DM) have increased risk for bone fractures which points towards impaired bone quality.Methods:We measured bone mineralization density distribution (BMDD) and osteocyte lacunae section (OLS) characteristics based on quantitative backscattered electron images of transiliac biopsy samples from n=26 premenopausal women with T2DM. Outcomes were compared to those from reference cohorts as well as between T2DM subgroups defined by clinical characteristics.Results:Comparison to references did not reveal any differences in BMDD (all p>0.05) but a lowered OLS-density in cancellous bone in T2DM (-14.9%, p<0.001). Neither BMDD nor OLS-characteristics differed in T2DM subgroups defined by HbA1c (<7% versus >7%). The average degree of bone mineralization (CaMean) was higher (0.44 wt%Ca in T2DM, 0.30 wt%Ca in reference) and consistently the calcium concentration between the tetracycline double labels (CaYoung) was higher (0.76 wt%Ca, all p<0.001) in cancellous versus cortical bone.Conclusions:Our findings suggest that bone matrix mineralization was neither affected by the presence nor by the glycemic control of T2DM in our study cohort. The intra-individual differences between cancellous and cortical bone mineralization gave evidence for differences in the time course of the early mineralization process in these compartments in general.     

Computational and Empirical Trans-hydrogen Bond Deuterium Isotope Shifts Suggest that N1–N3 A:U Hydrogen Bonds of RNA are Shorter than those of A:T Hydrogen Bonds of DNA

Density functional theory calculations of isolated Watson–Crick A:U and A:T base pairs predict that adenine ¹³C2 trans-hydrogen bond deuterium isotope shifts due to isotopic substitution at the pyrimidine H3, ^2hΔ¹³C2, are sensitive to the hydrogen-bond distance between the N1 of adenine and the N3 of uracil or thymine, which supports the notion that ^2hΔ¹³C2 is sensitive to hydrogen-bond strength. Calculated ^2hΔ¹³C2 values at a given N1–N3 distance are the same for isolated A:U and A:T base pairs. Replacing uridine residues in RNA with 5-methyl uridine and substituting deoxythymidines in DNA with deoxyuridines do not statistically shift empirical ^2hΔ¹³C2 values. Thus, we show experimentally and computationally that the C7 methyl group of thymine has no measurable affect on ^2hΔ¹³C2 values. Furthermore, ^2hΔ¹³C2 values of modified and unmodified RNA are more negative than those of modified and unmodified DNA, which supports our hypothesis that RNA hydrogen bonds are stronger than those of DNA. It is also shown here that ^2hΔ¹³C2 is context dependent and that this dependence is similar for RNA and DNA. Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.     

Comparison of artificial light photobioreactors and other production systems using Porphyridium cruentum

A new type of preparative photobioreactor for high quality production of microalgae is developed for hatchery-nursery of marine animals, as well as for fine chemicals extraction. Of modular conception, two artificial light photobioreactors in plastic and stainless steel are designed so as to provide strictly controlled conditions in an attempt to increase quality and diminish cost prices. They are assessed for production of Porphyridum cruentum and compared to conventional transparent tanks and solar photobioreactors. The concentration and productivity obtained are ten-fold higher than with hatchery tanks, which leads to a significant drop in cost price of biomass. Comparison is also made with a 10 m² solar photobioreactor operated in the south of France, for which biomass cost price is half that of 1.5 m² artificial light photobioreactor. Extrapolations erasing size discrepancy show that the cost price of the two technologies are not very different. This revised version was published online in June 2006 with corrections to the Cover Date.     

密度制约作用对箭叶淫羊藿有性繁殖时期形态特征的影响

运用回归分析和非参数检验方法,研究了箭叶淫羊藿(Epimedium sagittatum)在有性繁殖的三个时期克隆片段密度对其各个形态特征的影响,以揭示其资源和繁殖投资情况。结果表明：箭叶淫羊藿在三个有性繁殖期间克隆片段密度对其各个形态特征的影响显著。从回归分析的R2指数来看,其克隆片段密度增大对三个生长时期的制约作用是由弱到强,同时在有性繁殖期间随克隆片段密度的增加其资源投资趋向于有性繁殖;从非参数检验结果来看,有性繁殖期间箭叶淫羊藿明显增加其叶数、叶宽等来获取更多的资源用于提高其繁殖能力,以取得生存。     

Chirality in the Absence of Rigid Stereogenic Elements: Steric and Electronic Effects on the Configurational Stability of C3 Symmetric Residual Tris‐Aryl Phosphanes

Residual stereoisomers result whenever closed subsets of appropriately substituted interconverting isomers (the residual stereoisomers) are generated from a full set of stereoisomers under the operation of a favored stereomerization mechanism. In the case of the three‐bladed propellers, differentiation of the edges of the blades and strict correlation in the motion of the rings are the prerequisites for the existence of residual stereoisomers. In these systems, the two‐ring flip mechanism is the lowest energy process. It does not interconvert all possible conformational stereoisomers generated by helicity and the three‐blade‐hub rotors. In the case of C₃ symmetric systems, two noninterconverting subgroups (the residual stereoisomers) are generated, each one constituted of quickly interconverting diastereoisomers. A series of tris‐aryl phosphanes, structurally designed for existing as residual enantiomers or diastereoisomers, bearing substituents differing in size and electronic properties on the aryl rings, were synthesized and characterized. The configurational stability of residual phosphanes, evaluated by dynamic ¹H‐ and ³¹P‐NMR analysis and by dynamic enantioselective high‐performance liquid chromatography (HPLC), was found 10 kcal mol^‐1 lower than that shown by the corresponding phosphane‐oxides. In accordance with the calculations, an unexpectedly low barrier for phosphorus pyramidal inversion was invoked as responsible for the scarce configurational stability of the residual tris‐arylphosphanes. Chirality 26:601–606, 2014. © 2014 Wiley Periodicals, Inc.     

中国外来入侵植物的分布格局及其与环境因子和人类活动的关系

认识区域尺度上外来入侵植物的分布格局及其成因对预测入侵的影响和入侵种的管理具有重要意义。该文采用聚类分析和排序的方法分析了我国外来入侵植物的空间格局,并利用多元线性逐步回归和典范对应分析探讨了自然环境因子和人类活动强度对中国32个省级空间单位(省市自治区,不包括香港和澳门)中外来入侵植物分布的影响。结果表明,中国各省外来入侵植物物种数从南到北逐渐减少,导致这一格局的主要因子为无霜期;各省外来入侵植物物种密度由东南海岸向内陆递减,造成这一趋势的主要影响因素为交通密度;纬度是解释中国各省外来入侵植物物种组成变异的主要因子,因此中国32个省区可归为低、中、高纬度区3大类型。在此基础上预测中国东南部地区有遭受更多外来植物入侵的可能;此外,交通发达的区域也将成为外来植物入侵的热点区,应该引起有关部门的重视。     

黄芪甲苷对人骨髓间充质干细胞体外增殖及细胞因子表达的影响

目的：探讨黄芪甲苷对人骨髓间充质干细胞体外增殖及细胞因子表达的影响。方法：采用Percoll密度离心法和贴壁法分离纯化hBMSC;流式细胞术检测hBMSC表面标志;MTT法检测不同浓度黄芪甲苷干预72h后hBMSC的增殖情况;Real-timePCR法检测经黄芪甲苷干预后hBMSC对SCF、VEGF、SDF-1、GM-CSFmRNA的表达水平。结果：成功分离培养出laBMSC;不同浓度（20、40、80、160、320mg／mL）的黄芪甲苷可促进hBMSC增殖（P〈0．05）,其中160mg／mL组促增殖最明显;黄芪甲苷可促进hBMSC对SCF、VEGF、SDF-1mRNA的表达,而GM—CSFmRNA表达无明显变化。结论：黄芪甲苷可促进hBMSC体外增殖,可能与其促进hBMSC对SCF、VEGF、SDF-1mRNA表达有关。     

Linkage disequilibrium and natural selection for mimicry in the Batesian mimic Hypolimnas misippus (L.) (Lepidoptera: Nymphalidae) in the Afrotropics

On two occasions, on opposite sides of the African continent (Cape Coast, Ghana, and Dar es Salaam, Tanzania), high adult population densities in the polymorphic butterfly Hypolimnas misippus (a presumed mimic of Danaus chrysippus) were followed by linkage disequilibrium in combinations of fore‐ and hindwing colour patterns. On both occasions, disequilibrium was caused by significant changes in morph frequencies favouring rarer and more mimetic forms. Recaptures were too few for analysis at Dar, although the changes there took place within a single generation and must have been the result of differential survival. Recapture rate data and survival rate estimates at Cape Coast support the hypothesis that selective predation was responsible, as does the observation of synchronous linkage disequilibrium at Dar in the model D. chrysippus, indicating parasitic mimicry. There was clear selection for the perfection of mimicry for forewings at Dar and for hindwings at Cape Coast. Disequilibrium is also reported for two other sites, Legon (Ghana) and Boksburg (South Africa) and, in all four sites, it was associated with an increase in the most mimetic forms. New chemical evidence is presented to support the contention that D. chrysippus is a defended model. Although all the evidence leads to the conclusion that H. misippus is a Batesian mimic of D. chrysippus, many questions remain, particularly with regard to the identity of predators, the episodic nature of selective predation events, and their apparent lack of lasting and significant impact on overall gene frequencies. We conclude that H. misippus presents both challenges and opportunities for studies on mimicry, and we suggest that linkage disequilibrium can be a useful generic indicator for Gestalt predation on polymorphic prey. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100 , 180–194.     

Identification of Epithelial to Mesenchymal Transition as a Novel Source of Fibroblasts in Intestinal Fibrosis

Intestinal fibrosis is a major complication of Crohn disease (CD), but the precise mechanism by which it occurs is incompletely understood. As a result, specific therapies to halt or even reverse fibrosis have not been explored. Here, we evaluated the contribution of epithelial to mesenchymal transition (EMT) to intestinal fibrosis associated with a mouse model of CD and also human inflammatory bowel disease. Mice administered intrarectal 2,4,6-trinitrobenzene sulfonic acid (TNBS) develop inflammation and fibrosis that resembles CD both histologically and by immunologic profile. We utilized this model to molecularly probe the contribution of EMT to intestinal fibrosis. Additionally, we utilized double-transgenic VillinCre;R26Rosa-lox-STOP-lox-LacZ mice, in which removal of the STOP cassette by Cre recombinase in villin⁺ intestinal epithelial cells activates permanent LacZ expression, to lineage trace epithelial cells that might undergo EMT upon TNBS administration. TNBS-induced fibrosis is associated with the presence of a significant number of cells that express both epithelial and mesenchymal markers. In the lineage tagged transgenic mice, the appearance of LacZ⁺ cells that also express the fibroblast marker FSP1 unequivocally demonstrates EMT. Transforming growth factor (TGF)-β1, a known inducer of EMT in epithelial cells, induces EMT in rat intestinal epithelial cells in vitro, and bone morphogenic protein-7, an antagonist of TGF-β1, inhibits EMT and fibrosis both in vitro and in the TNBS-treated mice. Our study demonstrates that EMT contributes to intestinal fibrosis associated with the TNBS-induced model of Crohn colitis and that inhibition of TGF-β1 with recombinant human bone morphogenic protein-7 prevents this process and prevents fibrosis.