Phylogeography and conservation genetics of a giant lobelia (Lobelia giberroa) in Ethiopian and Tropical East African mountains

Lobelia giberroa is a giant rosette plant growing in the afro-montane belt of the afro-alpine environment, a unique and little-studied ecosystem occupying the high mountains of eastern Africa. We analysed amplified fragment length polymorphisms (AFLPs) from 11 mountain systems in Ethiopia and Tropical East Africa to infer the phylogeographical history of the species. A total of 191 individuals were investigated from 25 populations. Principal coordinate analysis and population structure analyses revealed three major phylogeographical groups: the Ethiopian mountains and one group on each side of the Rift Valley in Tropical East Africa, respectively: Elgon-Cherangani and Kenya-Aberdare-Kilimanjaro-Meru. Analysis of Molecular Variance showed 55.7% variance among the three groups, suggesting an old divergence. Together with a clear geographical substructure within the main groups, this pattern indicates gradual expansion and supports the montane forest bridge hypothesis, stating that the area occupied by forest was larger and more continuous in previous interglacials and earlier in the present interglacial. Genetic diversity was lower in Ethiopia than in the other two main groups, possibly due to an ancient founder effect when Ethiopia was colonized from the south.     

β-多样性的研究：应用多元回归和典范分析研究生态方差的分解

 β-多样性刻画了地理区域中不同地点物种组成的变化,是理解生态系统功能、生物多样性保护和生态系统管理的一个重要概念。该文介绍了如何从群落组成,相关环境和空间数据角度去分析β-多样性。β-多样性可以通过计算每个地点的多样性指数,进而对可能解释点之间差异的因子所作的假设进行检验来研究。也可以将涵盖所有点的群落组成数据表看作是一系列环境和空间变量的函数,进行直接分析。这种分析应用统计方法将多样性指数或群落组成数据表的方差进行关于环境和空间变量的分解。该文对方差分解进行阐述。方差分解是利用环境和空间变量来解释β-多样性的一种方法。β-多样性是生态学家用来比较不同地点或同一地点不同生态群落的一种手段。方差分解就是将群落组成数据表的总方差无偏分解成由各个解释变量所决定的子方差。调整的决定系数提供了针对多元回归和典范冗余分析的无偏估计。 方差分解后,可以对感兴趣的方差解释部分进行显著性检验,同时绘出基于这部分方差解释的预测图。     

Une nouvelle observation d’une métastase testiculaire d’un adénocarcinome prostatique: Aspects diagnostiques et éthiopathogéniques

Testicular metastases from prostatic adenocarcinoma are rare. They are often asymptomatic and diagnosed incidentally or at autopsy after orchidectomy in more advanced stages of the disease. The authors report a new case and review the diagnosis and aetiopathogenesis of these metastases. A 67-year-old patient with prostatic adenocarcinoma presented with painless right testicular mass for two months with no inflammatory signs. Germ cell tumour serum markers were negative. Scrotal ultrasound showed a large testicular tumour measuring 7×4×3cm. Histological examination revealed a solid non-differentiated tumour, not suggestive of primary testicular tumour. The immunohistochemical panel confirmed the prostate as the primary site due to the positivity of cytokeratins, PSA and PSAP and the negativity of classical markers of germ cell tumours. Testicular metastases from prostatic adenocarcinoma are rare, but their incidence is currently on the increase. They are often asymptomatic and discovered after pulpectomy. This diagnosis must be considered in the case of a testicular mass in patients over the age of 50 with a history of prostatic adenocarcinoma. The diagnosis was established after orchidectomy by histological examination and immunohistochemical tests.     

Natural and manipulated populations of the treehole mosquito, Ochlerotatus triseriatus, at its northernmost range limit in southern Ontario, Canada.

Ochlerotatus triseriatus, the eastern treehole mosquito, reaches its northernmost range limit in the extreme southeast of Canada. As a known vector of West Nile and La Crosse encephalitis viruses and a potential vector of eastern equine encephalitis, its population biology is of interest. In southern Ontario, high larval densities occur in urban woodlots within sugar maple and American beech treehole communities comprising rotifers, nematode worms, mites, other dipterans, and scirtid beetles. Treehole water was characterized by low dissolved oxygen levels and seasonally variable pH and temperature, with the latter being most influential on local populations. Densities were significantly higher (up to 503 larvae 100 ml(-1)) in tree holes close to the forest floor (<1 m) and in experimental tree holes seeded with autumn-shed maple leaves as opposed to leaves of black oak and beech. In this locality, weekly sampling showed Oc. triseriatus to be multivoltine, with mass egg hatching beginning under coldwater (<10 degrees C) conditions in March/April, and thereafter producing three successful generations with a possible, less successful fourth in late summer. Some 1st instar larvae were present in water as cold as 0.7 degree C. Compared with larval psychodids living in the same tree hole, population losses of Oc. triseriatus due to washout during major rainfall events were negligible despite high flowthrough of water derived from stemflow.     

CD16 promotes Escherichia coli sepsis through an FcR gamma inhibitory pathway that prevents phagocytosis and facilitates inflammation

Sepsis, a leading cause of death worldwide, involves proinflammatory responses and inefficient bacterial clearance. Phagocytic cells play a crucial part in the prevention of sepsis by clearing bacteria through host innate receptors. Here we show that the FcRgamma adaptor, an immunoreceptor tyrosine-based activation motif (ITAM)-bearing signal transduction subunit of the Fc receptor family, has a deleterious effect on sepsis. FcRgamma(-/-) mice show increased survival during peritonitis, owing to markedly increased E. coli phagocytosis and killing and to lower production of the proinflammatory cytokine tumor necrosis factor (TNF)-alpha. The FcRgamma-associated receptor that inhibits E. coli phagocytosis is FcgammaRIII (also called CD16), and its absence protects mice from sepsis. FcgammaRIII binds E. coli, and this interaction induces FcRgamma phosphorylation, recruitment of the tyrosine phosphatase SHP-1 and phosphatidylinositide-3 kinase (PI3K) dephosphorylation. Decreased PI3K activity inhibits E. coli phagocytosis and increases TNF-alpha production through Toll-like receptor 4. We identified the phagocytic receptor negatively regulated by FcRgamma on macrophages as the class A scavenger receptor MARCO. E. coli-FcgammaRIII interaction induces the recruitment of SHP-1 to MARCO, thereby inhibiting E. coli phagocytosis. Thus, by binding FcgammaRIII, E. coli triggers an inhibitory FcRgamma pathway that both impairs MARCO-mediated bacterial clearance and activates TNF-alpha secretion.     

The minimum information required for reporting a molecular interaction experiment (MIMIx)

A wealth of molecular interaction data is available in the literature, ranging from large-scale datasets to a single interaction confirmed by several different techniques. These data are all too often reported either as free text or in tables of variable format, and are often missing key pieces of information essential for a full understanding of the experiment. Here we propose MIMIx, the minimum information required for reporting a molecular interaction experiment. Adherence to these reporting guidelines will result in publications of increased clarity and usefulness to the scientific community and will support the rapid, systematic capture of molecular interaction data in public databases, thereby improving access to valuable interaction data.     

Lipophosphoramidates as lipidic part of lipospermines for gene delivery

The DNA compacting properties of polyamines (especially spermine) are well-known, hence the use of spermine as the cationic part in several synthetic DNA carriers. Here, we describe the synthesis of modified spermines, with a "lipophosphoramidate" as the lipidic part, and their use for efficient in vitro transfection. Physicochemical measurements (particle size, zeta potentials, pKa determination) and gel retardation assays were also performed. Theoretical membrane-disrupting ability was established by FRET. Taken together, our results indicate that lipophosphoramidates constitute an interesting alternative to "classical" lipidic parts of cationic lipids used as DNA carriers.     

Reprint of "Structural and mechanistic aspects of Amt/Rh proteins" [J. Struct. Biol. 158 (2007) 472-481

Amt/Rh proteins, which mediate movement of ammonium across cell membranes, are spread throughout the three kingdoms of life. Most functional studies on various members of the family have been performed using cellular assays in heterologous expression systems, which are, however, not very well suited for detailed mechanistic studies. Although now generally considered to be ammonia conducting channels, based on a number of experimental studies and structural insights, the possibility remains that some plant Amts facilitate net ammonium ion transport. The Escherichia coli channel AmtB has become the model system of choice for analysis of the mechanism of ammonia conductance, increasingly also through molecular dynamics simulations. Further progress in a more detailed mechanistic understanding of these proteins requires a reliable in vitro assay using purified protein, allowing quantitative kinetic measurements under a variety of experimental conditions for different Amt/Rh proteins, including mutants. Here, we critically review the existing functional data in the context of the most interesting and unresolved mechanistic questions and we present our results, obtained using an in vitro assay set up with the purified E. coli channel AmtB.