A genome-wide association study for celiac disease identifies risk variants in the region harboring IL2 and IL21

We tested 310,605 SNPs for association in 778 individuals with celiac disease and 1,422 controls. Outside the HLA region, the most significant finding (rs13119723; P = 2.0 x 10(-7)) was in the KIAA1109-TENR-IL2-IL21 linkage disequilibrium block. We independently confirmed association in two further collections (strongest association at rs6822844, 24 kb 5' of IL21; meta-analysis P = 1.3 x 10(-14), odds ratio = 0.63), suggesting that genetic variation in this region predisposes to celiac disease.     

Common variants near MC4R are associated with fat mass, weight and risk of obesity

To identify common variants influencing body mass index (BMI), we analyzed genome-wide association data from 16,876 individuals of European descent. After previously reported variants in FTO, the strongest association signal (rs17782313, P = 2.9 x 10(-6)) mapped 188 kb downstream of MC4R (melanocortin-4 receptor), mutations of which are the leading cause of monogenic severe childhood-onset obesity. We confirmed the BMI association in 60,352 adults (per-allele effect = 0.05 Z-score units; P = 2.8 x 10(-15)) and 5,988 children aged 7-11 (0.13 Z-score units; P = 1.5 x 10(-8)). In case-control analyses (n = 10,583), the odds for severe childhood obesity reached 1.30 (P = 8.0 x 10(-11)). Furthermore, we observed overtransmission of the risk allele to obese offspring in 660 families (P (pedigree disequilibrium test average; PDT-avg) = 2.4 x 10(-4)). The SNP location and patterns of phenotypic associations are consistent with effects mediated through altered MC4R function. Our findings establish that common variants near MC4R influence fat mass, weight and obesity risk at the population level and reinforce the need for large-scale data integration to identify variants influencing continuous biomedical traits.     

Free fatty acids regulate insulin secretion from pancreatic beta cells through GPR40

Diabetes, a disease in which carbohydrate and lipid metabolism are regulated improperly by insulin, is a serious worldwide health issue. Insulin is secreted from pancreatic beta cells in response to elevated plasma glucose, with various factors modifying its secretion. Free fatty acids (FFAs) provide an important energy source as nutrients, and they also act as signalling molecules in various cellular processes, including insulin secretion. Although FFAs are thought to promote insulin secretion in an acute phase, this mechanism is not clearly understood. Here we show that a G-protein-coupled receptor, GPR40, which is abundantly expressed in the pancreas, functions as a receptor for long-chain FFAs. Furthermore, we show that long-chain FFAs amplify glucose-stimulated insulin secretion from pancreatic beta cells by activating GPR40. Our results indicate that GPR40 agonists and/or antagonists show potential for the development of new anti-diabetic drugs.     

The crystal structure of the photoprotein aequorin at 2.3 A resolution

Aequorin is a calcium-sensitive photoprotein originally obtained from the jellyfish Aequorea aequorea. Because it has a high sensitivity to calcium ions and is biologically harmless, aequorin is widely used as a probe to monitor intracellular levels of free calcium. The aequorin molecule contains four helix-loop-helix 'EF-hand' domains, of which three can bind calcium. The molecule also contains coelenterazine as its chromophoric ligand. When calcium is added, the protein complex decomposes into apoaequorin, coelenteramide and CO2, accompanied by the emission of light. Apoaequorin can be regenerated into active aequorin in the absence of calcium by incubation with coelenterazine, oxygen and a thiol agent. Cloning and expression of the complementary DNA for aequorin were first reported in 1985 (refs 2, 6), and growth of crystals of the recombinant protein has been described; however, techniques have only recently been developed to prepare recombinant aequorin of the highest purity, permitting a full crystallographic study. Here we report the structure of recombinant aequorin determined by X-ray crystallography. Aequorin is found to be a globular molecule containing a hydrophobic core cavity that accommodates the ligand coelenterazine-2-hydroperoxide. The structure shows protein components stabilizing the peroxide and suggests a mechanism by which calcium activation may occur.     

Pro-sequence of subtilisin can guide the refolding of denatured subtilisin in an intermolecular process

Subtilisin E, an alkaline serine protease consisting of a single polypeptide chain of 275 amino acids is produced from a pre-pro-protein. The pre-sequence functions as the signal peptide for protein secretion across the membrane. Deletion of the pro-sequence yields mature but inactive subtilisin: the 77-amino acid pro-sequence must precede the mature subtilisin to guide the latter into an active conformation. Pro-subtilisin denatured in 6 M guanidine-HCl can be self-processed to the active enzyme intramolecularly, with concomitant cleavage of the pro-sequence, when dialysed against renaturing buffer. We have constructed an active-centre mutant of pro-subtilisin (Asp 32----Asn) which is not processed to active enzyme, unlike the wild-type pro-subtilisin, because intramolecular processing is prevented. Here we report an intermolecular pathway for the refolding of the inactive mature protein to an active enzyme in vitro with the aid of exogenously added pro-sequence. We establish conditions under which the mature inactive form, as well as acid-denatured subtilisins Carlsberg and BPN', can be renatured by the mutant pro-subtilisin.     

牙鲆贫血症病毒分离株的特性

用CHSE－214细胞，从患贫血症的牙鲆肾脏组织分离出一株病毒。电镜揭示为无囊膜、6面体、粒子直径约60nm；理化特性表明：病毒复制不受IUdR、BVdU的影响，对氯仿、乙醚不敏感性，热（60℃，30min）、酸（pH3．0，3h）中稳定；可被抗IPNV－Sp、Ab和VR－299株血清中和，其中抗Sp株血清的ND50为1:2560;病毒能在5～30℃增殖，最适为15～25℃；在盐度0．8～2．0％的培养液中，生长无明显差别；在16种鲑科和非鲑科鱼类细胞上，15℃培养1～4d出现CPE；感染细胞丫啶橙染色显示为黄绿色；用BirnavirusYAV株引物，PCR检出该病毒。结果提示该病毒株应属dsRNA的Birnavirus。     

Firefly luciferase: an adenylate-forming enzyme for multicatalytic functions

Firefly luciferase is a member of the acyl-adenylate/thioester-forming superfamily of enzymes and catalyzes the oxidation of firefly luciferin with molecular oxygen to emit light. Knowledge of the luminescence mechanism catalyzed by firefly luciferase has been gathered, leading to the discovery of a novel catalytic function of luciferase. Recently, we demonstrated that firefly luciferase has a catalytic function of fatty acyl-CoA synthesis from fatty acids in the presence of ATP, Mg²⁺ and coenzyme A. Based on identification of fatty acyl-CoA genes in firefly, Drosophila, and non-luminous click beetles, we then proposed that the evolutionary origin of firefly luciferase is a fatty acyl-CoA synthetase in insects. Further, we succeeded in converting the fatty acyl-CoA synthetase of non-luminous insects into functional luciferase showing luminescence activity by site-directed mutagenesis.     

Osteoprotection by semaphorin 3A

The bony skeleton is maintained by local factors that regulate bone-forming osteoblasts and bone-resorbing osteoclasts, in addition to hormonal activity. Osteoprotegerin protects bone by inhibiting osteoclastic bone resorption, but no factor has yet been identified as a local determinant of bone mass that regulates both osteoclasts and osteoblasts. Here we show that semaphorin 3A (Sema3A) exerts an osteoprotective effect by both suppressing osteoclastic bone resorption and increasing osteoblastic bone formation. The binding of Sema3A to neuropilin-1 (Nrp1) inhibited receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation by inhibiting the immunoreceptor tyrosine-based activation motif (ITAM) and RhoA signalling pathways. In addition, Sema3A and Nrp1 binding stimulated osteoblast and inhibited adipocyte differentiation through the canonical Wnt/β-catenin signalling pathway. The osteopenic phenotype in Sema3a?/? mice was recapitulated by mice in which the Sema3A-binding site of Nrp1 had been genetically disrupted. Intravenous Sema3A administration in mice increased bone volume and expedited bone regeneration. Thus, Sema3A is a promising new therapeutic agent in bone and joint diseases.     

产甲烷阶段季铵化合物的厌氧生物降解性研究(英文)

基于厌氧序批式测试系统,研究了一组季铵化合物的最终生物降解性和对生物气产生过程的毒性效果.四个测试物中每个化合物均带有四个相同的烷基,通式为R4N+Br-(TEAB,TPAB,TOAB和TODAB分别对应R=C2,C5,C8,C18,).测试物的矿化程度被用来评估其最终厌氧生物降解性;对碳源D-葡萄糖代谢过程的毒性可以利用测试物对生物气生成过程的抑制效果来指示.研究结果表明:带有偶碳数烷基链的季铵化合物,即TEAB、TOAB和TODAB在20 mg/L(以C计)能够被很容易地降解为CO2和CH4,它们对生物气生成过程的毒性随着所带烷基链长的增长而减小.测试物中带有最长碳链的TODAB,即使碳浓度提高到100 mg/L也可以顺利降解;并且在200 mg/L的高浓度条件下也没有发现其对代谢过程的毒性证据.相反,带有奇数碳链的TPAB很难被厌氧生物降解,而且在所有测试物中显示出最强的厌氧毒性,200 mg/L时的生物气抑制率高达69%.