The airborne metagenome in an indoor urban environment

The indoor atmosphere is an ecological unit that impacts on public health. To investigate the composition of organisms in this space, we applied culture-independent approaches to microbes harvested from the air of two densely populated urban buildings, from which we analyzed 80 megabases genomic DNA sequence and 6000 16S rDNA clones. The air microbiota is primarily bacteria, including potential opportunistic pathogens commonly isolated from human-inhabited environments such as hospitals, but none of the data contain matches to virulent pathogens or bioterror agents. Comparison of air samples with each other and nearby environments suggested that the indoor air microbes are not random transients from surrounding outdoor environments, but rather originate from indoor niches. Sequence annotation by gene function revealed specific adaptive capabilities enriched in the air environment, including genes potentially involved in resistance to desiccation and oxidative damage. This baseline index of air microbiota will be valuable for improving designs of surveillance for natural or man-made release of virulent pathogens.     

黄体酮对成年斑马鱼下丘脑-垂体-性腺轴相关基因转录表达的干扰效应

黄体酮(P4)是一种类固醇激素。为了探究P4的内分泌干扰效应, 选择成年斑马鱼(Danio rerio)作为受试生物, 研究了P4对斑马鱼下丘脑-垂体-性腺轴(HPG轴)相关基因转录表达影响。成年斑马鱼在不同浓度P4(2、11和16 ng•L–1)下处理21 d。结果显示: 暴露于高浓度组的P4能够抑制雌鱼大脑中促性腺激素释放激素2(gnrh2)、促性腺激素释放激素3(gnrh3), 卵泡刺激素(fshb)、雌激素受体1(esr1)基因的转录表达; 然而诱导了雄鱼大脑中fshb、黄体生成素(lhb)、雄激素受体(ar)基因的转录表达, 这些转录变化暗示了P4对成年斑马鱼有潜在的弱雄激素效应。此外, P4暴露对雌鱼卵巢和雄鱼精巢类固醇合成途径中固醇激素合成急性调节蛋白(star)、细胞色素p450介导侧链裂解酶(cyp11a1)、17α羟化酶(cyp17)、卵巢细胞色素P450芳香化酶(cyp19a1a)、11β羟化酶(cyp11b)、羟基类固醇3β脱氢酶(hsd3b)、羟基类固醇20β脱氢酶(hsd20b)、羟基类固醇17β脱氢酶3(hsd17b3)、羟基类固醇11β脱氢酶2(hsd11b2)以及受体信号途径中孕激素受体(pgr)、esr1、ar基因的转录表达没有显著影响。可见, 在P4暴露下, 斑马鱼大脑比性腺更加敏感。总而言之, P4能够改变斑马鱼大脑中HPG轴相关基因的转录表达水平, 进而对斑马鱼的内分泌系统具有潜在的危险。     

NEDD4L基因变异体与内蒙古地区蒙古族人群中高血压 的相关分析

目的：探讨内蒙古地区蒙古族人群中NEDD4L基因多态性位点rs4149601(G/A)突变与高血压的相关性。方法：应用病例对 照方法研究包头地区蒙古族高血压病个体308 例及蒙古族血压正常个体454 例。检测所有个体舒张压,收缩压。使用TaqMan PCR技术进行rs4149601 多态基因分型。结果：rs4149601 多态基因型及等位基因分布在GG 基因型、GA 基因型、AA 等位基因的 频率在高血压组及对照组分别为54.7%,92.8%;11.4%及56.2%;71.4%,7.9%。rs4149601 多态基因型及等位基因分布与对照组差 异有显著性。应用多元logistic 回归分析对性别、年龄进行校正后发现rs4149601 多态基因与高血压病患病风险相关。结论：上皮 细胞钠通道亚单位基因多态性(rs4149601)同内蒙古地区蒙古族人群高血压病发病有关。     

Formation of micro‐spherulitic barite in association with organic matter within sulfidized stromatolites of the 3.48 billion‐year‐old Dresser Formation,Pilbara Craton

The shallow marine and subaerial sedimentary and hydrothermal rocks of the ~3.48 billion‐year‐old Dresser Formation are host to some of Earth's oldest stromatolites and microbial remains. This study reports on texturally distinctive, spherulitic barite micro‐mineralization that occur in association with primary, autochthonous organic matter within exceptionally preserved, strongly sulfidized stromatolite samples obtained from drill cores. Spherulitic barite micro‐mineralization within the sulfidized stromatolites generally forms submicron‐scale aggregates that show gradations from hollow to densely crystallized, irregular to partially radiating crystalline interiors. Several barite micro‐spherulites show thin outer shells. Within stromatolites, barite micro‐spherulites are intimately associated with petrographically earliest dolomite and nano‐porous pyrite enriched in organic matter, the latter of which is a possible biosignature assemblage that hosts microbial remains. Barite spherulites are also observed within layered barite in proximity to stromatolite layers, where they are overgrown by compositionally distinct (Sr‐rich), coarsely crystalline barite that may have been sourced from hydrothermal veins at depth. Micro‐spherulitic barite, such as reported here, is not known from hydrothermal systems that exceed the upper temperature limit for life. Rather, barite with near‐identical morphology and micro‐texture is known from zones of high bio‐productivity under low‐temperature conditions in the modern oceans, where microbial activity and/or organic matter of degrading biomass controls the formation of spherulitic aggregates. Hence, the presence of micro‐spherulitic barite in the organic matter‐bearing Dresser Formation sulfidized stromatolites lend further support for a biogenic origin of these unusual, exceptionally well‐preserved, and very ancient microbialites.     

Interaction between beta-cyclodextrin and 1,10-phenanthroline: uncommon 2:3 inclusion complex in the solid state

The crystallographic structure of the complex formed by beta-cyclodextrin with 1,10-phenanthroline has been studied by X-ray diffraction. The result shows that the complex adopts an uncommon 2:3 stoichiometry in solid state, that is, every complex unit contains three 1,10-phenanthroline molecules and two beta-cyclodextrin molecules, where two 1,10-phenanthroline molecules individually occupy two cyclodextrin cavities, and the third guest molecule is located in the interstitial space between two head-to-head cyclodextrin molecules. The intermolecular hydrogen bonds between the adjacent complex units further link these individual monomers to a channel-type assembly. Furthermore, 1H and 2D NMR spectroscopy has been employed to investigate the inclusion behavior between the host beta-cyclodextrin and guest 1,10-phenanthroline in aqueous solution.     

Sitagliptin activates the p62–Keap1–Nrf2 signalling pathway to alleviate oxidative stress and excessive autophagy in severe acute pancreatitis-related acute lung injury

Acute lung injury (ALI) is a complication of severe acute pancreatitis (SAP). Sitagliptin (SIT) is a DPP4 inhibitor that exerts anti-inflammatory and antioxidant effects; however, its mechanism of action in SAP-ALI remains unclear. In this study, we investigated the effects of SIT on SAP-ALI and the specific pathways involved in SAP-induced lung inflammation, including oxidative stress, autophagy, and p62–Kelch-like ECH-associated protein 1 (Keap1)–NF-E2-related factor 2 (Nrf2) signalling pathways. Nrf2 knockout (Nrf2^−/−) and wild-type (WT) mice were pre-treated with SIT (100 mg/kg), followed by caerulein and lipopolysaccharide (LPS) administration to induce pancreatic and lung injury. BEAS-2B cells were transfected with siRNA-Nrf2 and treated with LPS, and the changes in inflammation, reactive oxygen species (ROS) levels, and autophagy were measured. SIT reduced histological damage, oedema, and myeloperoxidase activity in the lung, decreased the expression of pro-inflammatory cytokines, and inhibited excessive autophagy and ROS production via the activation of the p62–Keap1–Nrf2 signalling pathway and promotion of the nuclear translocation of Nrf2. In Nrf2-knockout mice, the anti-inflammatory effect of SIT was reduced, resulting in ROS accumulation and excessive autophagy. In BEAS-2B cells, LPS induced ROS production and activated autophagy, further enhanced by Nrf2 knockdown. This study demonstrates that SIT reduces SAP-ALI-associated oxidative stress and excessive autophagy through the p62–Keap1–Nrf2 signalling pathway and nuclear translocation of Nrf2, suggesting its therapeutic potential in SAP-ALI.Subject terms: Macroautophagy, Acute pancreatitis     

Diverse flowering responses subjecting to ambient high temperature in soybean under short-day conditions

Flowering time is one of important agronomic traits determining the crop yield and affected by high temperature. When facing high ambient temperature, plants often initiate early flowering as an adaptive strategy to escape the stress and ensure successful reproduction. However, here we find opposing ways in the short-day crop soybean to respond to different levels of high temperatures, in which flowering accelerates when temperature changes from 25 to 30 °C, but delays when temperature reaches 35 °C under short day. phyA-E1, possibly photoperiodic pathway, is crucial for 35 °C-mediated late flowering, however, does not contribute to promoting flowering at 30 °C. 30 °C-induced up-regulation of FT2a and FT5a leads to early flowering, independent of E1. Therefore, distinct responsive mechanisms are adopted by soybean when facing different levels of high temperatures for successful flowering and reproduction.     

小钻‘白城杨2号’小孢子发生及花粉大小变异

利用醋酸洋红染色压片技术,以温室水培小钻‘白城杨2号’(Populus×xiaozhuanica W.Y.Hsu et Liangcv.‘Baicheng-2’)为材料,对其小孢子发生过程中染色体行为及花粉大小变异进行研究。结果表明:(1)‘白城杨2号’小孢子母细胞减数分裂过程中染色体行为存在一定比例的异常现象,包括终变期单价体、中期Ⅰ染色体提前分离、后期Ⅰ和Ⅱ落后染色体和染色体桥、末期Ⅰ和Ⅱ微核、中期Ⅱ纺锤体定位异常以及胞质分裂异常等,这些异常现象的发生与‘白城杨2号’杂种起源有密切关系。(2)‘白城杨2号’小孢子母细胞减数分裂过程中核仁数目存在动态变化,末期Ⅰ和Ⅱ的子核中最多可看到8个小核仁,可能与杨属树种的多倍体起源有关,其染色体组中可能包含8对具核仁组织者区的染色体。(3)‘白城杨2号’产生空瘪花粉率为3.67%,饱满花粉直径在21.3～52.2μm之间,频率分布总体呈近似高斯分布,0.69%的花粉直径超过37μm,表明其可能产生少量未减数的2n花粉。     

苛求芽孢杆菌基因组DNA提取方法的比较

目的:比较不同方法提取苛求芽孢杆菌基因组DNA的差异。方法:用经典CTAB提取法、改进CTAB法(溶菌酶处理结合CTAB提取法)、UniQ柱吸附提取法制备苛求芽孢杆菌基因组DNA,比较产物完整性和用于PCR扩增的有效性。结果:三种方法制备基因组DNA纯度接近,但改进CTAB法产率最高,UniQ法产率最低。经典CTAB法和UniQ法提取基因组DNA易降解。三种方法所得基因组DNA用于PCR扩增效率接近。结论:溶菌酶裂解结合CTAB提取更适合制备苛求芽孢杆菌基因组DNA。     

The Gossypium hirsutum TIR-NBS-LRR gene GhDSC1 mediates resistance against Verticillium wilt

Improving genetic resistance is a preferred method to manage Verticillium wilt of cotton and other hosts. Identifying host resistance is difficult because of the dearth of resistance genes against this pathogen. Previously, a novel candidate gene involved in Verticillium wilt resistance was identified by a genome-wide association study using a panel of Gossypium hirsutum accessions. In this study, we cloned the candidate resistance gene from cotton that encodes a protein sharing homology with the TIR-NBS-LRR receptor-like defence protein DSC1 in Arabidopsis thaliana (hereafter named GhDSC1). GhDSC1 expressed at higher levels in response to Verticillium wilt and jasmonic acid (JA) treatment in resistant cotton cultivars as compared to susceptible cultivars and its product was localized to nucleus. The transfer of GhDSC1 to Arabidopsis conferred Verticillium resistance in an A. thaliana dsc1 mutant. This resistance response was associated with reactive oxygen species (ROS) accumulation and increased expression of JA-signalling-related genes. Furthermore, the expression of GhDSC1 in response to Verticillium wilt and JA signalling in A. thaliana displayed expression patterns similar to GhCAMTA3 in cotton under identical conditions, suggesting a coordinated DSC1 and CAMTA3 response in A. thaliana to Verticillium wilt. Analyses of GhDSC1 sequence polymorphism revealed a single nucleotide polymorphism (SNP) difference between resistant and susceptible cotton accessions, within the P-loop motif encoded by GhDSC1. This SNP difference causes ineffective activation of defence response in susceptible cultivars. These results demonstrated that GhDSC1 confers Verticillium resistance in the model plant system of A. thaliana, and therefore represents a suitable candidate for the genetic engineering of Verticillium wilt resistance in cotton.