Self-assembling phospholipid filaments

Aqueous dispersions of double-chain phospholipids spontaneously assemble into closed bilayers called vesicles (or liposomes). Although the vesicles are in general topologically spherical, cylindrical and helical liposomes have sometimes been observed. We present here video-enhanced microscopic studies of a diacetylenic phospholipid dispersed in ethanol/water, which reveal the existence of unusual bilayer morphologies. On cooling the dispersion from the isotropic phase, we have observed the formation of long (of the order of hundreds of micrometres), thin (0.2-2 microns) filaments, which fluctuate strongly. When the temperature is decreased further, the filaments rapidly retract into a mass of lipid. At constant temperature, on the other hand, the filaments transform into torus or ring-like vesicles. Such non-spherical structures have been predicted theoretically but not previously observed experimentally.     

Presenilin is required for proper morphology and function of neurons in C. elegans

Mutations in the human presenilin genes cause the most frequent and aggressive forms of familial Alzheimer's disease (FAD). Here we show that in addition to its role in cell fate decisions in non-neuronal tissues, presenilin activity is required in terminally differentiated neurons in vivo. Mutations in the Caenorhabditis elegans presenilin genes sel-12 and hop-1 result in a defect in the temperature memory of the animals. This defect is caused by the loss of presenilin function in two cholinergic interneurons that display neurite morphology defects in presenilin mutants. The morphology and function of the affected neurons in sel-12 mutant animals can be restored by expressing sel-12 only in these cells. The wild-type human presenilin PS1, but not the FAD mutant PS1 A246E, can also rescue these morphological defects. As lin-12 mutant animals display similar morphological and functional defects to presenilin mutants, we suggest that presenilins mediate their activity in postmitotic neurons by facilitating Notch signalling. These data indicate cell-autonomous and evolutionarily conserved control of neural morphology and function by presenilins.     

贝加尔与江苏蝶类区系比较及成因分析

对贝加尔和江苏地区蝶类区系分布做了调查,其中大约有近200份的蝴蝶标本采集于贝加尔地区、有1000多份标本采集于江苏地区．在完成此次调查工作的基础上,结合前人工作总结出了两地区的蝶类名录,江苏地区蝶类共10科105属178种,贝加尔地区蝶类7科39属55种．为此,还比较两地区蝶类区系多样性的相似性和差异性,并分别从气候、寄主植物分布和蝶类起源与演化3个方面分析了造成两地区蝶类分布相似性和差异性的原因．     

Genome-wide association study identifies a susceptibility locus for thyrotoxic periodic paralysis at 17q24.3

Thyrotoxic periodic paralysis (TPP) is a potentially life-threatening complication of thyrotoxicosis. We conducted a genome-wide association study (GWAS) and a replication study with a total of 123 southern Chinese with TPP (cases) and 1,170 healthy controls and identified a susceptibility locus on chromosome 17q24.3 near KCNJ2 (rs312691: odds ratio (OR) = 3.3; P(meta-analysis) = 1.8 × 10(-14)). All subjects with TPP also had Graves' disease, and subsequent TPP versus Graves' disease comparison confirmed that the association at 17q24.3 was specific to TPP. The area under the curve (AUC) of rs312691 genotype for risk prediction of TPP in subjects with Graves' disease was 0.73. Expression quantitative trait locus (eQTL) analysis identified SNPs in the region flanking rs312691 (±10 kb) that could potentially affect KCNJ2 expression (P = 0.0001). Our study has identified a susceptibility locus associated with TPP and provides insight into the causes of TPP.     

Mutations in sodium-borate cotransporter SLC4A11 cause recessive congenital hereditary endothelial dystrophy (CHED2)

Congenital hereditary endothelial dystrophy (CHED) is a heritable, bilateral corneal dystrophy characterized by corneal opacification and nystagmus. We describe seven different mutations in the SLC4A11 gene in ten families with autosomal recessive CHED. Mutations in SLC4A11, which encodes a membrane-bound sodium-borate cotransporter, cause loss of function of the protein either by blocking its membrane targeting or nonsense-mediated decay.     

Membrane-shed vesicles from the parasite <Emphasis Type="Italic">Trichomonas vaginalis</Emphasis>: characterization and their association with cell interaction

Trichomonas vaginalis is a common sexually transmitted parasite that colonizes the human urogenital tract, where it remains extracellular and adheres to epithelial cells. Infections range from asymptomatic to highly inflammatory, depending on the host and the parasite strain. Despite the serious consequences associated with trichomoniasis disease, little is known about parasite or host factors involved in attachment of the parasite-to-host epithelial cells. Here, we report the identification of microvesicle-like structures (MVs) released by T. vaginalis. MVs are considered universal transport vehicles for intercellular communication as they can incorporate peptides, proteins, lipids, miRNA, and mRNA, all of which can be transferred to target cells through receptor–ligand interactions, fusion with the cell membrane, and delivery of a functional cargo to the cytoplasm of the target cell. In the present study, we demonstrated that T. vaginalis release MVs from the plasma and the flagellar membranes of the parasite. We performed proteomic profiling of these structures demonstrating that they possess physical characteristics similar to mammalian extracellular vesicles and might be selectively charged with specific protein content. In addition, we demonstrated that viable T. vaginalis parasites release large vesicles (LVs), membrane structures larger than 1 µm that are able to interact with other parasites and with the host cell. Finally, we show that both populations of vesicles present on the surface of T vaginalis are induced in the presence of host cells, consistent with a role in modulating cell interactions.     

SNP and haplotype mapping for genetic analysis in the rat

The laboratory rat is one of the most extensively studied model organisms. Inbred laboratory rat strains originated from limited Rattus norvegicus founder populations, and the inherited genetic variation provides an excellent resource for the correlation of genotype to phenotype. Here, we report a survey of genetic variation based on almost 3 million newly identified SNPs. We obtained accurate and complete genotypes for a subset of 20,238 SNPs across 167 distinct inbred rat strains, two rat recombinant inbred panels and an F2 intercross. Using 81% of these SNPs, we constructed high-density genetic maps, creating a large dataset of fully characterized SNPs for disease gene mapping. Our data characterize the population structure and illustrate the degree of linkage disequilibrium. We provide a detailed SNP map and demonstrate its utility for mapping of quantitative trait loci. This community resource is openly available and augments the genetic tools for this workhorse of physiological studies.