Association between APOC1 Polymorphism and Alzheimer’s Disease: A Case-Control Study and Meta-Analysis

Background

Previous association studies examining the relationship between the APOC1 polymorphism and susceptibility to Alzheimer’s disease (AD) have shown conflicting results, and it is not clear if an APOC1 variant acts as a genetic risk factor in AD etiology across multiple populations.

Methods

To confirm the risk association between APOC1 and AD, we designed a case-control study and also performed a meta-analysis of previously published studies.

Results

Seventy-nine patients with AD and one hundred fifty-six unrelated controls were included in case-control study. No association was found between the variation of APOC1 and AD in stage 1 of our study. However, our meta-analysis pooled a total of 2092 AD patients and 2685 controls. The APOC1 rs11568822 polymorphism was associated with increased AD risk in Caucasians, Asians and Caribbean Hispanics, but not in African Americans. APOE ε4 carriers harboring the APOC1 insertion allele, were more prevalent in AD patients than controls (χ² = 119.46, OR = 2.79, 95% CI = 2.31–3.36, P<0.01).

Conclusions

The APOC1 insertion allele, in combination with APOE ε4, likely serves as a potential risk factor for developing AD.     

南通沿海滩涂耐盐植物重金属抗性内生细菌的筛选及生物多样性

【目的】沿海滩涂耐盐植物重金属抗性内生细菌的筛选及其促生长潜在能力的研究有助于我们获得一些能够耐受并促进耐盐植物在被Cd2+、Pb2+、Hg2+、Cu2+,Zn2+等重金属离子污染的贫瘠的沿海滩涂上正常生长的菌株,达到既能够利用广袤的滩涂生物资源产生经济价值又能够净化生态环境的目的。【方法】以江苏南通沿海滩涂地区的4种耐盐植物为材料,采用稀释平板涂布法从中分离得到45株内生细菌,从中挑取23株代表性的菌株,对其进行抗重金属Cu2+、Pb2+、Cd2+、Zn2+,Hg2+的活性筛选;固氮、解磷、吲哚乙酸(IAA)的产生、1-氨基环丙烷-1-羧酸(ACC)脱氨酶活性等促生指标以及NaCl耐受能力的筛选。【结果】发现分离所得的大多数细菌能够耐受高浓度的Cu2+以及Pb2+,但是对Cd2+、Zn2+,Hg2+的耐受能力则较弱;26.1%的细菌具有固氮能力,21.7%的细菌具有解磷能力,60.9%的细菌能够产生IAA,39.1%的细菌含有ACC脱氨酶。对他们进行16S rRNA基因鉴定后发现,他们分属于芽胞杆菌属(Bacillus)、喜盐芽胞杆菌属(Halobacillus)、海洋芽胞杆菌属(Oceanobacillus)、微小杆菌属(Exiguobacterium)、沙雷氏菌属(Serratia)、短波单胞菌属(Brevundimonas)、弧菌属(Vibrio)、葡萄球菌属(Staphylococcus)共8个属,显示了丰富的多样性。其中菌株KLBMP 2432以及菌株KLBMP 2447为潜在的新种。【结论】沿海滩涂地区的耐盐植物内生细菌具有丰富多样的生物多样性以及促生长能力,且存在潜在的新种资源,并对重金属Cu2+,Pb2+具有较强的抗性。     

Genome-wide analysis of primary auxin-responsive Aux/IAA gene family in maize (Zea mays. L.)

The phytohormone auxin is important in various aspects of organism growth and development. Aux/IAA genes encoding short-lived nuclear proteins are responsive primarily to auxin induction. Despite their physiological importance, systematic analysis of Aux/IAA genes in maize have not yet been reported. In this paper, we presented the isolation and characterization of maize Aux/IAA genes in whole-genome scale. A total of 31 maize Aux/IAA genes (ZmIAA1 to ZmIAA31) were identified. ZmIAA genes are distributed in all the maize chromosomes except chromosome 2. Aux/IAA genes expand in the maize genome partly due to tandem and segmental duplication events. Multiple alignment and motif display results revealed major maize Aux/IAA proteins share all the four conserved domains. Phylogenetic analysis indicated Aux/IAA family can be divided into seven subfamilies. Putative cis-acting regulatory DNA elements involved in auxin response, light signaling transduction and abiotic stress adaption were observed in the promoters of ZmIAA genes. Expression data mining suggested maize Aux/IAA genes have temporal and spatial expression pattern. Collectively, these results will provide molecular insights into the auxin metabolism, transport and signaling research.     

An examination of targeted gene neighborhoods in strawberry

Background  

Strawberry (Fragaria spp.) is the familiar name of a group of economically important crop plants and wild relatives that also represent an emerging system for the study of gene and genome evolution. Its small stature, rapid seed-to-seed cycle, transformability and miniscule basic genome make strawberry an attractive system to study processes related to plant physiology, development and crop production; yet it lacks substantial genomics-level resources. This report addresses this deficiency by characterizing 0.71 Mbp of gene space from a diploid species (F. vesca). The twenty large genomic tracks (30-52 kb) captured as fosmid inserts comprise gene regions with roles in flowering, disease resistance, and metabolism.     

Distinctive binding of three antagonistic peptides to the ephrin-binding pocket of the EphA4 receptor

The EphA4 receptor tyrosine kinase interacts with ephrin ligands to regulate many processes, ranging from axon guidance and nerve regeneration to cancer malignancy. Thus antagonists that inhibit ephrin binding to EphA4 could be useful for a variety of research and therapeutic applications. In the present study we characterize the binding features of three antagonistic peptides (KYL, APY and VTM) that selectively target EphA4 among the Eph receptors. Isothermal titration calorimetry analysis demonstrated that all three peptides bind to the ephrin-binding domain of EphA4 with low micromolar affinity. Furthermore, the effects of a series of EphA4 mutations suggest that the peptides interact in different ways with the ephrin-binding pocket of EphA4. Chemical-shift changes observed by NMR spectroscopy upon binding of the KYL peptide involve many EphA4 residues, consistent with extensive interactions and possibly receptor conformational changes. Additionally, systematic replacement of each of the 12 amino acids of KYL and VTM identify the residues critical for EphA4, binding. The peptides exhibit a long half-life in cell culture medium which, with their substantial binding affinity and selectivity for EphA4, makes them excellent research tools to modulate EphA4 function.     

beta-oxidation - strategies for the metabolism of a wide variety of acyl-CoA esters

Living organisms are exposed to a number of different fatty acids and their various derivatives arising either via endogenous synthesis or from exogenous sources. These hydrophobic compounds can play specific metabolic, structural or endocrinic functions in the organisms before their elimination, which can be metabolism to CO(2) or to more polar lipid metabolites allowing their excretion. Quantitatively, one of the major pathways metabolizing fatty acids is beta-oxidation, which consists of a set of four reactions operating at the carbons 2 or 3 of acyl-CoA esters and shortening of the acyl-chain. To allow the beta-oxidation of acyl groups with various steric variants to proceed, different strategies have been developed. These strategies include evolution of beta-oxidation enzymes as paralogues showing specificity with respect to either chain-length or modified acyl-chain, metabolic compartmentalization in eukaryotic cells, controlling of substrate transport across membranes, development of auxiliary enzyme systems, acquisition of enzymes with adaptive active sites and recruiting and optimizing enzymes from non-homologous sources allowing them to catalyze a parallel set of reactions with different substrate specificities.     

Doppel is an N-glycosylated, glycosylphosphatidylinositol-anchored protein. Expression in testis and ectopic production in the brains of Prnp(0/0) mice predisposed to Purkinje cell loss

The Prnd gene encodes a homolog of the cellular prion protein (PrP(C)) called doppel (Dpl). Up-regulation of Prnd mRNA in two distinct lines of PrP gene ablated (Prnp(0/0)) mice, designated Rcm0 and Ngsk, is associated with death of Purkinje cells. Using recombinant Dpl expressed in Escherichia coli and mouse neuroblastoma cells we demonstrate that wild type (wt) Dpl, like PrP(C), adopts a predominantly alpha-helical conformation, forms intramolecular disulfide bonds, has two N-linked oligosaccharides, and is presented on the cell surface via a glycosylphosphatidylinositol anchor. Dpl protein was detected in testis of wt mice. Using Triton X-114 phase partitioning to enrich for glycosylphosphatidylinositol-anchored proteins, Dpl was detected in brain samples from Rcm0 Prnp(0/0) mice but was absent in equivalent samples from wt mice and ZrchI Prnp(0/0) mice, indicating that ectopic expression of this protein may cause cerebellar pathology in Rcm0 mice. Biochemical and structural similarities between PrP(C) and Dpl documented here parallel the observation that ataxic Ngsk Prnp(0/0) mice can be rescued by overexpression of wild-type PrP transgenes, and suggest that cell surface PrP(C) can antagonize the toxic effect of Dpl expressed in the central nervous system.     

十字花科10属种与油菜萝卜胞质不育系杂交的花粉萌发情况观察

对10属种十字花科植物与油菜萝卜胞质不育系杂交时花粉在柱头上粘合、萌发、花粉管伸长等情况进行观察。结果表明：（1）海甘蓝花粉粒粘合较难;（2）48 h内无瓣焊菜〖WTBX〗(Rorippa dubia)〖WTBX〗、毛果诸葛菜(Orychophragmus violaceus)、桂竹香(Cheiranthus cheiri)、海甘蓝(Crambe abyssinica)花粉管的伸长受阻于花粉萌发启动之时,花粉壁内形成胼胝质塞;播娘蒿、紫罗兰、荠菜花粉管伸长但未进入乳突细胞;芝麻菜花粉管进入乳突细胞而未进入柱头,‘浠水白’(Brassica campestris)、蓝花子有花粉管进入柱头及花柱而未进入胚囊。