Trefoil factors

Trefoil factor family (TFF) peptides have many in vivo and in vitro effects on restitution, wound healing, apoptosis, cell motility, adhesion and vectorial ion pumping, amongst others. (125)I-TFF peptides bind to cell membranes with classical saturable ability. It would be surprising if there were not TFF-protein interactions that would explain these actions, but to date no convincing TFF-binding partner has been shown which unambiguously takes part in any of these functions. Nevertheless, several TFF-binding proteins exist, including the small intestinal CRP-ductin (muclin), which binds TFF2, and the recently described gastric foveolar proteins TFIZ1 (TFF1-binding) and blottin (TFF2-binding), any of which may yet interact in novel ways to elicit TFF-mediated events. This review describes the expression and, where known, the functions of such proteins.     

Barttin is a Cl- channel beta-subunit crucial for renal Cl- reabsorption and inner ear K+ secretion.

Renal salt loss in Bartter's syndrome is caused by impaired transepithelial transport in the loop of Henle. Sodium chloride is taken up apically by the combined activity of NKCC2 (Na+-K--2Cl- cotransporters) and ROMK potassium channels. Chloride ions exit from the cell through basolateral ClC-Kb chloride channels. Mutations in the three corresponding genes have been identified that correspond to Bartter's syndrome types 1-3. The gene encoding the integral membrane protein barttin is mutated in a form of Bartter's syndrome that is associated with congenital deafness and renal failure. Here we show that barttin acts as an essential beta-subunit for ClC-Ka and ClC-Kb chloride channels, with which it colocalizes in basolateral membranes of renal tubules and of potassium-secreting epithelia of the inner ear. Disease-causing mutations in either ClC-Kb or barttin compromise currents through heteromeric channels. Currents can be stimulated further by mutating a proline-tyrosine (PY) motif on barttin. This work describes the first known beta-subunit for CLC chloride channels and reveals that heteromers formed by ClC-K and barttin are crucial for renal salt reabsorption and potassium recycling in the inner ear.     

Über das Problem der Welkekrankheiten bei Pflanzen

Summary Lycomarasmin is a plasma poison produced byFusarium lycopersici Sacc., the pathogen of tomato wilt. In a dilution of 10^–2 and 10^–3 mol it causes a pathological wilting of tomato plants and usually disturbs their water balance; in a dilution of 10^–4 mol it only disturbs the latter.In the present paper, we develop the theory that in sufficient concentration lycomariasmin damages or destroys thesemipermeability of the plasma boundary layer.In a dilution of 10^–2 and 10^–3 mol of lycomarasmin the semipermeability of the plasma membranes iscompletely destroyed. Thus on the one hand the conditions for osmotic pressure disappear and irreversible pathological wilting appears, and on the other hand cellular fluid passes into the transpiration current of the cell-membrane and leads to a momentary excess humidity, particularly in the leaf-tissues, and thus also to a momentaryexcess transpiration.The water-deficit regularly observed in wilt-literature is therefore not the cause of pathological wilting but, just as the wilting itself, a consequence of the distruction of the semipermeability of the plasma boundary layer.In a dilution of 10^–4 mol lycomarasmin apparently only affects the permeability of the exterior plasma boundary layer forwater, but not for sugars etc. Therefore it only produces an excess of fluid in the leaf tissues and thus an excess transpiration, but no definite inactivation of the plasma membrane and therefore also no pathological wilt.     

水平排列硅光二极管色传感器及其特性

简要介绍水平排列硅光二极管色传感器的制作工艺，该器件波长在５００ｎｍ到６５０ｎｍ范围内有一个单调的近于线性的光谱响应。入射光波长为６００ｎｍ时，入射光强度化五个数量级，测出的波长基本不变，器件波长分辨率、最低入射光强、长时间测量的波长漂移以及波长温漂系数等特性的测量结果表明：该类色传感器已达高性能实用要求。     

Ecology drives a global network of gene exchange connecting the human microbiome

Horizontal gene transfer (HGT), the acquisition of genetic material from non-parental lineages, is known to be important in bacterial evolution. In particular, HGT provides rapid access to genetic innovations, allowing traits such as virulence, antibiotic resistance and xenobiotic metabolism to spread through the human microbiome. Recent anecdotal studies providing snapshots of active gene flow on the human body have highlighted the need to determine the frequency of such recent transfers and the forces that govern these events. Here we report the discovery and characterization of a vast, human-associated network of gene exchange, large enough to directly compare the principal forces shaping HGT. We show that this network of 10,770 unique, recently transferred (more than 99% nucleotide identity) genes found in 2,235 full bacterial genomes, is shaped principally by ecology rather than geography or phylogeny, with most gene exchange occurring between isolates from ecologically similar, but geographically separated, environments. For example, we observe 25-fold more HGT between human-associated bacteria than among ecologically diverse non-human isolates (P = 3.0 × 10(-270)). We show that within the human microbiome this ecological architecture continues across multiple spatial scales, functional classes and ecological niches with transfer further enriched among bacteria that inhabit the same body site, have the same oxygen tolerance or have the same ability to cause disease. This structure offers a window into the molecular traits that define ecological niches, insight that we use to uncover sources of antibiotic resistance and identify genes associated with the pathology of meningitis and other diseases.     

Investigation of Sparse Data Mouse Imaging Using Micro-CT with a Carbon-Nanotube-Based X-ray Source

There has been a renewed interest in algorithm development for image reconstruction from highly incomplete data in computed tomography(CT).Such algorithms may lead to reduced imaging dose and time,and to the design of innovative configurations tailored to specific imaging tasks.In recent years,a carbon-nanotube(CNT)-based field-emission x-ray source has been developed,which offers easy electronic control of radiation and thus can be an ideal candidate for gated imaging.We have recently proposed algorithms f...     

Sexual selection enables long-term coexistence despite ecological equivalence

Empirical data indicate that sexual preferences are critical for maintaining species boundaries, yet theoretical work has suggested that, on their own, they can have only a minimal role in maintaining biodiversity. This is because long-term coexistence within overlapping ranges is thought to be unlikely in the absence of ecological differentiation. Here we challenge this widely held view by generalizing a standard model of sexual selection to include two ubiquitous features of populations with sexual selection: spatial variation in local carrying capacity, and mate-search costs in females. We show that, when these two features are combined, sexual preferences can single-handedly maintain coexistence, even when spatial variation in local carrying capacity is so slight that it might go unnoticed empirically. This theoretical study demonstrates that sexual selection alone can promote the long-term coexistence of ecologically equivalent species with overlapping ranges, and it thus provides a novel explanation for the maintenance of species diversity.