一株分离自四川温泉的嗜热鞘丝藻新种鉴定

为了确定分离自四川甘孜地区温泉的嗜热丝状菌株B121的分类信息, 为探索其应用价值提供遗传学分析基础, 对其进行基因组分析、系统发育分析、二级结构预测、形态学鉴定以及结合菌株钠盐耐受性和固氮能力的整体分析。在16S rRNA的系统发育分析中, 发现菌株 B121与菌株Thermoleptolyngbya oregonensis PCC 8501, Thermoleptolyngbya albertanoae ETS-08和Thermoleptolyngbya sp.O-77等嗜热鞘丝藻属菌株有较好的聚类。在16S-23S ITS二级结构预测分析中, 菌株B121的D1-D1'区域与属内参考菌株有一定的相似性, 序列同一性也较高, 但都没有到达广义的同种物种标准, 并且V2, BoxB及V3区域与其他对照菌株的差异较大。结合形态学分析, 确定菌株B121 是Thermoleptolyngbya属下的一个新种。菌株B121可在最高浓度为0.5 M的NaCl和NaNO₃培养基中生存, 也可在浓度为1 M的NaCl培养基中存活。当气相条件为Ar:N₂: CO₂=79:20:1 (体积比)时, 菌株B121的乙炔还原速率可以达到2564.1 nmol/(g·h)。     

Perspectives on the prevention and treatment of infection for orthopedic tissue engineering applications

The emergence of orthopedic tissue engineering devices as viable clinical solutions demands that the field address significant clinical complications associated with the implantation of foreign materials in the body, especially infection. While tissue engi- neering has focused on the development of methods to regenerate and repair, until recently there has been a relative dearth of literature regarding the intersection of tissue engineering and infection. In particular, local delivery of antimicrobials has long been of clinical interest, but only recently has that been translated into the realm of tissue engineering. In this perspective, we briefly review major modes of local delivery for infection prevention and treatment and discuss possible strategies for preventing implant-associated infections.     

Synthesis of titanium oxycarbonitride by carbothermal reduction and nitridation of ilmenite with recycling of polyethylene terephthalate (PET)

An innovative and sustainable carbothermal reduction and nitridation (CTRN) process of ilmenite (FeTiO₃) using a mixture of polyethylene terephthalate (PET) and coal as the primary reductant under an H₂-N₂ atmosphere was proposed.The use of PET as an alternative source of carbon not only enhances the porosity of the pellets but also results in the separation of Fe from titanium oxycarbonitride (TiO_xC_yN_z) particles because of the differences in surface tension.The experiments were carried out at 1250℃ for 3 h using four different PET contents ranging from 25wt% to 100wt% in the reductant.X-ray diffraction (XRD),scanning electron microscopy (SEM) in conjunction with energy-dispersive X-ray spectroscopy (EDX),and LECO elemental analysis were used to study the phases and microstructures of the reduced samples.In the case of 75wt% PET,iron distinctly separated from the synthesized TiO_xC_yN_z phase.With increasing PET content in the sample,the reduction and nitridation rates substantially increased.The synthesis of an oxycarbonitride with stoichiometry of TiO_0.02C_0.13N_0.85 with minimal intermediate titanium sub-oxides was achieved.The results also showed that the iron particles formed from CTRN of FeTiO₃ exhibited a spherical morphology,which is conducive for Fe removal via the Becher process.     

Plant genetics: increased outcrossing in hothead mutants

Arising from: S. J. Lolle, J. L. Victor, J. M. Young & R. E. Pruitt 434, 505-509 (2005); Lolle et al. reply. Lolle et al. report that loss-of-function alleles of the HOTHEAD (HTH) gene in Arabidopsis thaliana are genetically unstable, giving rise to wild-type revertants. On the basis of the reversion of many other genetic markers in hth plants, they suggested a model in which a cache of extragenomic information could cause genes to revert to the genotype of previous generations. In our attempts to reproduce this phenomenon, we discovered that hth mutants show a marked tendency to outcross (unlike wild-type A. thaliana, which is almost exclusively self-fertilizing). Moreover, when hth plants are grown in isolation, their genetic inheritance is completely stable. These results may provide an alternative explanation for the genome wide non-mendelian inheritance reported by Lolle et al.     

一种新的基于FSM的UIO序列生成算法

在一致性测试中,如何有效地生成UIO序列一直为人们所关注.针对此,提出一种新的基于FSM的UIO序列生成算法,进而由C语言编写实现.该思想采用栈和结构体相结合的思路来保存UIO序列的完整路径,实验结果表明能够正确生成FSM图中各个状态的最短UIO序列.     

Newly identified loci that influence lipid concentrations and risk of coronary artery disease

To identify genetic variants influencing plasma lipid concentrations, we first used genotype imputation and meta-analysis to combine three genome-wide scans totaling 8,816 individuals and comprising 6,068 individuals specific to our study (1,874 individuals from the FUSION study of type 2 diabetes and 4,184 individuals from the SardiNIA study of aging-associated variables) and 2,758 individuals from the Diabetes Genetics Initiative, reported in a companion study in this issue. We subsequently examined promising signals in 11,569 additional individuals. Overall, we identify strongly associated variants in eleven loci previously implicated in lipid metabolism (ABCA1, the APOA5-APOA4-APOC3-APOA1 and APOE-APOC clusters, APOB, CETP, GCKR, LDLR, LPL, LIPC, LIPG and PCSK9) and also in several newly identified loci (near MVK-MMAB and GALNT2, with variants primarily associated with high-density lipoprotein (HDL) cholesterol; near SORT1, with variants primarily associated with low-density lipoprotein (LDL) cholesterol; near TRIB1, MLXIPL and ANGPTL3, with variants primarily associated with triglycerides; and a locus encompassing several genes near NCAN, with variants strongly associated with both triglycerides and LDL cholesterol). Notably, the 11 independent variants associated with increased LDL cholesterol concentrations in our study also showed increased frequency in a sample of coronary artery disease cases versus controls.     

Effect of bromocriptine on gonadal ornithine decarboxylase in vitro

Summary The alterations in ornithine decarboxylase activity in response to in vitro treatment with bromocriptine suggest the possible direct action of the drug on gonads.