Genetic variation in the KIF1B locus influences susceptibility to multiple sclerosis

The few loci associated with multiple sclerosis (MS) are all related to immune function. We report a GWA study identifying a new locus replicated in 2,679 cases and 3,125 controls. An rs10492972[C] variant located in the KIF1B gene was associated with MS with an odds ratio of 1.35 (P = 2.5 x 10(-10)). KIF1B is a neuronally expressed gene plausibly implicated in the irreversible axonal loss characterizing MS in the long term.     

A genome-wide association scan of nonsynonymous SNPs identifies a susceptibility variant for Crohn disease in ATG16L1

We performed a genome-wide association study of 19,779 nonsynonymous SNPs in 735 individuals with Crohn disease and 368 controls. A total of 7,159 of these SNPs were informative. We followed up on all 72 SNPs with P 0.4), these data suggest that the underlying biological process may be specific to Crohn disease.     

Evidence for complete denitrification in a benthic foraminifer

Benthic foraminifera are unicellular eukaryotes found abundantly in many types of marine sediments. Many species survive and possibly reproduce in anoxic habitats, but sustainable anaerobic metabolism has not been previously described. Here we demonstrate that the foraminifer Globobulimina pseudospinescens accumulates intracellular nitrate stores and that these can be respired to dinitrogen gas. The amounts of nitrate detected are estimated to be sufficient to support respiration for over a month. In a Swedish fjord sediment where G. pseudospinescens is the dominant foraminifer, the intracellular nitrate pool in this species accounted for 20% of the large, cell-bound, nitrate pool present in an oxygen-free zone. Similarly high nitrate concentrations were also detected in foraminifera Nonionella cf. stella and a Stainforthia species, the two dominant benthic taxa occurring within the oxygen minimum zone of the continental shelf off Chile. Given the high abundance of foraminifera in anoxic marine environments, these new findings suggest that foraminifera may play an important role in global nitrogen cycling and indicate that our understanding of the complexity of the marine nitrogen cycle is far from complete.     

Isotope-induced partial localization of core electrons in the homonuclear molecule N2

Because of inversion symmetry and particle exchange, all constituents of homonuclear diatomic molecules are in a quantum mechanically non-local coherent state; this includes the nuclei and deep-lying core electrons. Hence, the molecular photoemission can be regarded as a natural double-slit experiment: coherent electron emission originates from two identical sites, and should give rise to characteristic interference patterns. However, the quantum coherence is obscured if the two possible symmetry states of the electronic wavefunction ('gerade' and 'ungerade') are degenerate; the sum of the two exactly resembles the distinguishable, incoherent emission from two localized core sites. Here we observe the coherence of core electrons in N(2) through a direct measurement of the interference exhibited in their emission. We also explore the gradual transition to a symmetry-broken system of localized electrons by comparing different isotope-substituted species--a phenomenon analogous to the acquisition of partial 'which-way' information in macroscopic double-slit experiments.     

铝抑制拟南芥根尖PIN2循环和囊泡运输

铝对植物毒害作用最明显的症状是迅速抑制根尖生长. 然而, 铝抑制根尖生长的机制并不清楚. 本文研究了铝对生长素和生长素运输载体(PIN2)囊泡运输的影响. 结果表明, 铝抑制拟南芥根尖生长素运输, 其中过渡区生长素抑制率最高, 达66%. 布雷菲尔德菌素(Brefeldin A, BFA, 一种囊泡运输抑制剂)明显诱导PIN2囊泡在细胞内形成点状结构, 铝处理降低点状结构的大小, 表明铝抑制PIN2囊泡在细胞内的运输. 实时定量PCR和蛋白印迹反应发现, 铝增加PIN2基因的转录表达, 促进PIN2蛋白在细胞膜水平方向累积. 细胞骨架解聚药物处理表明, 铝抑制PIN2囊泡的运输, 主要通过破坏肌球蛋白微丝来完成. 铝处理下, 拟南芥根尖伸长区细胞比过渡区具有较少的铝吸收和较低的囊泡运输频率. 上述结果表明, 通过调节生长素运输载体(PIN2)在质膜与胞内移动, 阻碍生长素的运输, 铝抑制了拟南芥根尖的生长.     

Regulation of flowering time: all roads lead to Rome

Plants undergo a major physiological change as they transition from vegetative growth to reproductive development. This transition is a result of responses to various endogenous and exogenous signals that later integrate to result in flowering. Five genetically defined pathways have been identified that control flowering. The vernalization pathway refers to the acceleration of flowering on exposure to a long period of cold. The photoperiod pathway refers to regulation of flowering in response to day length and quality of light perceived. The gibberellin pathway refers to the requirement of gibberellic acid for normal flowering patterns. The autonomous pathway refers to endogenous regulators that are independent of the photoperiod and gibberellin pathways. Most recently, an endogenous pathway that adds plant age to the control of flowering time has been described. The molecular mechanisms of these pathways have been studied extensively in Arabidopsis thaliana and several other flowering plants.     

tRNA structural and functional changes induced by oxidative stress

Oxidatively damaged biomolecules impair cellular functions and contribute to the pathology of a variety of diseases. RNA is also attacked by reactive oxygen species, and oxidized RNA is increasingly recognized as an important contributor to neurodegenerative complications in humans. Recently, evidence has accumulated supporting the notion that tRNA is involved in cellular responses to various stress conditions. This review focuses on the intriguing consequences of oxidative modification of tRNA at the structural and functional level.