• 【单独或与乙酰辅酶a合酶一起异源表达的carboxidivorans CO脱氢酶可以还原CO2并通过丙酮丁醇梭菌氧化CO。】 复制标题 收藏 收藏
    DOI:10.1128/AEM.00829-17 复制DOI
    作者列表:Carlson ED,Papoutsakis ET
    BACKGROUND & AIMS: :With recent advances in synthetic biology, CO2 could be utilized as a carbon feedstock by native or engineered organisms, assuming the availability of electrons. Two key enzymes used in autotrophic CO2 fixation are the CO dehydrogenase (CODH) and acetyl coenzyme A (acetyl-CoA) synthase (ACS), which form a bifunctional heterotetrameric complex. The CODH/ACS complex can reversibly catalyze CO2 to CO, effectively enabling a biological water-gas shift reaction at ambient temperatures and pressures. The CODH/ACS complex is part of the Wood-Ljungdahl pathway (WLP) used by acetogens to fix CO2, and it has been well characterized in native hosts. So far, only a few recombinant CODH/ACS complexes have been expressed in heterologous hosts, none of which demonstrated in vivo CO2 reduction. Here, functional expression of the Clostridium carboxidivorans CODH/ACS complex is demonstrated in the solventogen Clostridium acetobutylicum, which was engineered to express CODH alone or together with the ACS. Both strains exhibited CO2 reduction and CO oxidation activities. The CODH reactions were interrogated using isotopic labeling, thus verifying that CO was a direct product of CO2 reduction, and vice versa. CODH apparently uses a native C. acetobutylicum ferredoxin as an electron carrier for CO2 reduction. Heterologous CODH activity depended on actively growing cells and required the addition of nickel, which is inserted into CODH without the need to express the native Ni insertase protein. Increasing CO concentrations in the gas phase inhibited CODH activity and altered the metabolite profile of the CODH-expressing cells. This work provides the foundation for engineering a complete and functional WLP in nonnative host organisms.IMPORTANCE Functional expression of CO dehydrogenase (CODH) from Clostridium carboxidivorans was demonstrated in C. acetobutylicum, which is natively incapable of CO2 fixation. The expression of CODH, alone or together with the C. carboxidivorans acetyl-CoA synthase (ACS), enabled C. acetobutylicum to catalyze both CO2 reduction and CO oxidation. Importantly, CODH exhibited activity in both the presence and absence of ACS. 13C-tracer studies confirmed that the engineered C. acetobutylicum strains can reduce CO2 to CO and oxidize CO during growth on glucose.
    背景与目标: : 随着合成生物学的最新进展,假设电子的可用性,CO2可以被天然或工程生物用作碳原料。自养CO2固定中使用的两种关键酶是CO脱氢酶 (CODH) 和乙酰辅酶a (乙酰辅酶a) 合酶 (ACS),它们形成了双功能的异四聚体复合物。CODH/ACS复合物可以可逆地将CO2催化为CO,从而在环境温度和压力下有效地实现了生物水煤气变换反应。CODH/ACS复合物是乙酰原菌用来固定CO2的Wood-Ljungdahl途径 (WLP) 的一部分,并且在天然宿主中已得到很好的表征。到目前为止,在异源宿主中仅表达了少数重组CODH/ACS复合物,但均未证明体内CO2还原。在这里,羧基梭菌CODH/ACS复合物的功能性表达在丙酮丁醇梭菌中得到证实,该梭菌经工程设计可单独或与ACS一起表达CODH。两种菌株均表现出CO2还原和CO氧化活性。使用同位素标记对CODH反应进行了询问,从而验证了CO是CO2还原的直接产物,反之亦然。CODH显然使用天然的丙酮丁基铁氧还蛋白作为减少CO2的电子载体。异源CODH活性取决于活跃生长的细胞,需要添加镍,镍被插入CODH中,而不需要表达天然的Ni插入酶蛋白。气相中CO浓度的增加会抑制CODH活性并改变表达CODH的细胞的代谢物谱。这项工作为在非本地宿主生物体中设计完整且功能性的WLP奠定了基础。重要的是,来自碳衣梭菌的CO脱氢酶 (CODH) 的功能表达在丙酮丁基梭菌中得到证明,该菌本身无法固定CO2。CODH单独或与C. carboxidivorans乙酰辅酶a合酶 (ACS) 一起表达,使C.Acetutylicum能够催化CO2还原和CO氧化。重要的是,CODH在存在和不存在ACS时均表现出活性。13c-示踪剂研究证实,工程改造的丙酮丁醇C菌株可以将CO2还原为CO,并在葡萄糖上生长过程中氧化CO。
  • 【生物质高温蒸汽气化中的共处理甲烷。】 复制标题 收藏 收藏
    DOI:10.1016/j.biortech.2012.10.033 复制DOI
    作者列表:Palumbo AW,Jorgensen EL,Sorli JC,Weimer AW
    BACKGROUND & AIMS: :High temperature steam gasification/reforming of biomass-methane mixtures was carried out in an indirectly heated entrained flow reactor to analyze the feasibility of controlling the output composition of the major synthesis gas products: H(2), CO, CO(2), CH(4). A 2(3) factorial experimental design was carried out and compared to thermodynamic equilibrium predictions. Experiments demonstrated the product gas composition is mostly dependent on temperature and that excess steam contributes to CO(2) formation. Results showed that with two carbon-containing reactants it is possible to control the gas composition of the major products. At 1500 °C, the equilibrium results accurately predicted the syngas composition and can be used to guide optimization of the syngas for downstream liquid fuel synthesis technologies.
    背景与目标: : 在间接加热的夹带流反应器中进行了生物质-甲烷混合物的高温蒸汽气化/重整,以分析控制主要合成气产物: H(2),CO,CO(2),CH(4) 的输出组成的可行性。进行了2(3) 个阶乘实验设计,并将其与热力学平衡预测进行了比较。实验表明,产物气体组成主要取决于温度,过量的蒸汽有助于形成CO(2)。结果表明,使用两种含碳反应物,可以控制主要产物的气体组成。在1500 °C时,平衡结果准确地预测了合成气的组成,并可用于指导下游液体燃料合成技术的合成气的优化。
  • 【转录共阻遏因子TLE3通过抑制MyoD转录因子的活性来调节肌源性分化。】 复制标题 收藏 收藏
    DOI:10.1074/jbc.M116.774570 复制DOI
    作者列表:Kokabu S,Nakatomi C,Matsubara T,Ono Y,Addison WN,Lowery JW,Urata M,Hudnall AM,Hitomi S,Nakatomi M,Sato T,Osawa K,Yoda T,Rosen V,Jimi E
    BACKGROUND & AIMS: :Satellite cells are skeletal muscle stem cells that provide myonuclei for postnatal muscle growth, maintenance, and repair/regeneration in adults. Normally, satellite cells are mitotically quiescent, but they are activated in response to muscle injury, in which case they proliferate extensively and exhibit up-regulated expression of the transcription factor MyoD, a master regulator of myogenesis. MyoD forms a heterodimer with E proteins through their basic helix-loop-helix domain, binds to E boxes in the genome and thereby activates transcription at muscle-specific promoters. The central role of MyoD in muscle differentiation has increased interest in finding potential MyoD regulators. Here we identified transducin-like enhancer of split (TLE3), one of the Groucho/TLE family members, as a regulator of MyoD function during myogenesis. TLE3 was expressed in activated and proliferative satellite cells in which increased TLE3 levels suppressed myogenic differentiation, and, conversely, reduced TLE3 levels promoted myogenesis with a concomitant increase in proliferation. We found that, via its glutamine- and serine/proline-rich domains, TLE3 interferes with MyoD function by disrupting the association between the basic helix-loop-helix domain of MyoD and E proteins. Our findings indicate that TLE3 participates in skeletal muscle homeostasis by dampening satellite cell differentiation via repression of MyoD transcriptional activity.
    背景与目标: : 卫星细胞是骨骼肌干细胞,可为成人的产后肌肉生长,维持和修复/再生提供肌核。通常,卫星细胞是有丝分裂的静止细胞,但它们在响应肌肉损伤时被激活,在这种情况下,它们广泛增殖并表现出转录因子MyoD (肌发生的主要调节剂) 的上调表达。MyoD通过其碱性螺旋-环-螺旋结构域与E蛋白形成异二聚体,与基因组中的E盒结合,从而激活肌肉特异性启动子的转录。MyoD在肌肉分化中的核心作用增加了寻找潜在MyoD调节剂的兴趣。在这里,我们确定了Groucho/TLE家族成员之一的分裂的类转导增强子 (TLE3) 作为肌发生过程中MyoD功能的调节剂。TLE3在活化和增殖的卫星细胞中表达,其中TLE3水平的升高抑制了肌源性分化,相反,TLE3水平的降低促进了肌发生,同时增殖也随之增加。我们发现,通过其富含谷氨酰胺和丝氨酸/脯氨酸的结构域,TLE3通过破坏MyoD和E蛋白的基本螺旋-环-螺旋结构域之间的关联来干扰MyoD功能。我们的发现表明,TLE3通过抑制MyoD转录活性来抑制卫星细胞分化,从而参与骨骼肌稳态。
  • 【与已建立的人子宫内膜上皮和基质细胞系共培养对精子运动特性的影响。】 复制标题 收藏 收藏
    DOI:10.1093/humrep/12.6.1197 复制DOI
    作者列表:Guerin JF,Merviel P,Plachot M
    BACKGROUND & AIMS: The effects of co-culture of human spermatozoa with human immortalized endometrial cells - epithelial or stromal - on sperm movement characteristics, including hyperactivation, were studied using computer-assisted sperm analysis (CASA). Epithelial and stromal cell types could be separated following 8-10 days of culture of endometrial cells originating from human biopsies. Both cell types were immortalized by the SV 40 large T antigen. Co-incubation of sperm with epithelial and stromal monolayers enhanced the rate of hyperactivation24.9% (P <0.05) and 17.8% (P = 0.05) versus 9.5% as control, respectively, whereas the majority of motility parameters remained unchanged. Conditioned media had no effect upon sperm parameters, including hyperactivation. Co-incubation with either monolayer was able to maintain sperm motility over a longer period than incubation in control medium alone.

    In four patients whose spermatozoa did not exhibit hyperactivation, co-incubation with epithelial cells, but not conditioned medium, allowed normal rates of hyperactivation (range6.9-15.6%).

    背景与目标: 使用计算机辅助精子分析 (CASA) 研究了人类精子与人类永生化的子宫内膜细胞 (上皮或基质) 共培养对精子运动特征 (包括过度活化) 的影响。在培养源自人活检的子宫内膜细胞8-10天后,可以分离上皮和基质细胞类型。两种细胞类型都被SV 40大T抗原永生化。与9.5% 对照相比,将精子与上皮和基质单层共同孵育可分别提高高激活率24.9% (P <0.05) 和17.8% (P = 0.05),而大多数运动参数保持不变。条件培养基对精子参数 (包括过度活化) 没有影响。与单独在对照培养基中孵育相比,与任一单层共同孵育能够在更长的时间内保持精子活力。
    在四名精子未表现出过度活化的患者中,与上皮细胞共同孵育,但不是条件培养基,允许正常的过度激活率 (范围6.9-15.6%)。
  • 【Anti-Ro52抗体经常与特发性炎症性肌病患者血清中的anti-Jo-1抗体同时出现。】 复制标题 收藏 收藏
    DOI:10.1046/j.1365-2249.1997.4081308.x 复制DOI
    作者列表:Rutjes SA,Vree Egberts WT,Jongen P,Van Den Hoogen F,Pruijn GJ,Van Venrooij WJ
    BACKGROUND & AIMS: We analysed 112 idiopathic inflammatory myopathy (IIM) sera for the presence of anti-Ro, anti-La and anti-histidyl-tRNA synthetase (Jo-1) autoantibodies, and subsequently mapped B cell epitopes on the Ro52 protein recognized by anti-Ro52+ IIM sera. Sera were characterized by immunoblotting, ELISA and RNA precipitation. Both anti-Ro60 and anti-La activity was found in 4% of IIM sera. Anti-Ro52 antibodies were present in 20% of IIM sera. However, in anti-Jo-1+ IIM sera (21%), the frequency of the anti-Ro52 antibodies was found to be much higher (58%). No cross-reactivity between anti-Ro52 and anti-Jo-1 antibodies could be detected in these sera. To learn more about the nature of anti-Ro52 antibodies occurring in IIM sera, we analysed the major epitopes of the Ro52 protein targeted by anti-Ro52+ IIM sera by immunoprecipitation of in vitro translated Ro52 deletion mutants. The major epitope was mapped in the region bordered by amino acids 126 and 252. This part of the protein includes a long alpha-helical region which contains two potential coiled-coil domains as well as a leucine zipper motif. Although no difference in Ro52 epitope recognition between anti-Jo-1+ and anti-Jo-1- IIM sera could be observed, our results suggest that the autoimmune response against Ro52 and Jo-1 in IIM patients is coupled.

    背景与目标: 我们分析了112个特发性炎症性肌病 (IIM) 血清中存在抗Ro,抗La和抗组氨酸-tRNA合成酶 (Jo-1) 自身抗体,随后将b细胞表位绘制在anti-Ro52 IIM血清识别的Ro52蛋白上。通过免疫印迹,ELISA和RNA沉淀对血清进行表征。在4% 的IIM血清中发现了anti-Ro60和抗La活性。Anti-Ro52抗体存在于IIM血清的20% 中。然而,在anti-Jo-1 + IIM血清 (21%) 中,发现anti-Ro52抗体的频率要高得多 (58%)。在这些血清中未检测到anti-Ro52和anti-Jo-1抗体之间的交叉反应。为了更多地了解IIM血清中anti-Ro52抗体的性质,我们通过体外翻译的Ro52缺失突变体的免疫沉淀分析了anti-Ro52 IIM血清靶向的Ro52蛋白的主要表位。主要表位被定位在与氨基酸126和252接壤的区域中。蛋白质的这一部分包括一个长的 α 螺旋区域,该区域包含两个潜在的卷曲螺旋结构域以及亮氨酸拉链基序。尽管在anti-Jo-1和anti-Jo-1- IIM血清之间没有观察到Ro52表位识别的差异,但我们的结果表明IIM患者针对Ro52和Jo-1的自身免疫反应是偶联的。
  • 【离子活性产物对三维聚 (丙交酯-乙交酯) 支架上自组装矿物结构和组成的影响。】 复制标题 收藏 收藏
    DOI:10.1002/jbm.a.31437 复制DOI
    作者列表:Shin K,Jayasuriya AC,Kohn DH
    BACKGROUND & AIMS: :A biomimetic approach involving the self-assembly of mineral within the pores of three-dimensional porous polymer scaffolds is a promising strategy to integrate advantages of inorganic and organic phases into a single material for hard tissue engineering. Such a material enhances the ability of progenitor cells to differentiate down an osteoblast lineage in vitro and in vivo, compared with polymer scaffolds. The mechanisms regulating mineral formation in this one-step process, however, are poorly understood, especially the effects of ionic activity products (IP) of the mineralizing solution and incubation time. The aims of this study were to define the structure and composition of mineral formed within the pores of biodegradable polymer scaffolds as a function of IP and time. Three-dimensional poly(lactide-co-glycolide) scaffolds were fabricated by solvent casting/particulate leaching and incubated for 4-16 days in six variants of simulated body fluid whose IPs were varied by adjusting ionic concentrations. Scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy demonstrated the formation of carbonated apatite with sub-micrometer sized crystals that grew into spherical globules extending out of the scaffold pore surfaces. As IP increased, more mineral grew on the scaffold pore surfaces, but the apatite became less crystalline and the Ca/P molar ratio decreased from 1.63 +/- 0.005 to 1.51 +/- 0.002. Since morphology, composition, and structure of mineral are factors that affect cell function, this study demonstrates that the IP of the mineralizing solution is an important modulator of material properties, potentially leading to enhanced control of cell function.
    背景与目标: : 一种仿生方法,涉及矿物在三维多孔聚合物支架的孔中自组装,是一种将无机和有机相的优势整合到用于硬组织工程的单一材料中的有前途的策略。与聚合物支架相比,这种材料增强了祖细胞在体外和体内分化成骨细胞谱系的能力。然而,对这种一步过程中调节矿物形成的机制知之甚少,尤其是矿化溶液的离子活性产物 (IP) 和孵育时间的影响。这项研究的目的是定义在可生物降解的聚合物支架的孔中形成的矿物的结构和组成随IP和时间的变化。通过溶剂浇铸/颗粒浸出制备三维聚 (丙交酯-共-乙交酯) 支架,并在六种模拟体液变体中孵育4-16天,其IPs通过调节离子浓度而变化。扫描电子显微镜,x射线衍射和傅立叶变换红外光谱证明了碳酸磷灰石的形成,其亚微米尺寸的晶体长成球形小球,延伸出支架孔表面。随着IP的增加,更多的矿物在支架孔表面上生长,但是磷灰石变得不那么结晶,并且Ca/P摩尔比从1.63 +/- 0.005降低到1.51 +/- 0.002。由于矿物的形态,组成和结构是影响细胞功能的因素,因此这项研究表明,矿化溶液的IP是材料特性的重要调节剂,有可能导致对细胞功能的增强控制。
  • 【比较傅里叶变换红外研究细胞色素P-450cam和细胞色素P-420cam中的二级结构和CO血红素配体环境。】 复制标题 收藏 收藏
    DOI:10.1021/bi9700173 复制DOI
    作者列表:Mouro C,Jung C,Bondon A,Simonneaux G
    BACKGROUND & AIMS: For the first time, Fourier transform infrared spectroscopy has been applied to cytochrome P-450 to analyze the protein secondary structure. From Fourier self-deconvolution and fitting the infrared spectra in the amide I' region (1600-1700 cm-1), we estimate 44% alpha-helix, 31% beta-sheet, and 18% turns for substrate-free cytochrome P-450cam. In the presence of camphor, 54% alpha-helix and 310-helix, 21% beta-sheet, and 21% turns are obtained which agree with the crystallographic data of 53% alpha-helix, 19% beta-sheet, and 16% turns [Poulos, T. L., Finzel, B. C., & Howard, A. J. (1987) J. Mol. Biol. 195, 687-700]. Cytochrome P-420cam is produced from substrate-free cytochrome P-450cam in two ways(i) by temperature elevation up to 60 degrees C and (ii) by exposure to KSCN up to 1.5 M. The secondary structure composition is determined for each temperature and KSCN concentration and compared with the changes observed in the iron ligand CO stretch vibration bands appearing between 1900 and 2000 cm-1. Thermally induced cytochrome P-420 has an alpha-helix content of 19%, a beta-sheet content of 53%, 14% turns, and 5% antiparallel beta-sheets from intermolecular hydrogen bonds within protein aggregates. The formation of cytochrome P-420 as a function of the KSCN concentration indicates two types of cytochrome P-420. Up to 1 M KSCN, the induced cytochrome P-420 displays only little modification of the secondary structure, whereas at 1.5 M KSCN, larger changes are observed, resulting in 85% cytochrome P-420 without protein precipitation and containing 30% alpha-helix, 48% beta-sheet, and 17% turns. Infrared spectra in the iron ligand CO stretch region show several subconformers for cytochrome P-420. During the cytochrome P-420 formation, the CO stretch modes are shifted to higher frequencies by 3-11 cm-1, with a main feature at about 1964 cm-1, compared to those of substrate-free cytochrome P-450cam-CO.

    背景与目标: 首次将傅里叶变换红外光谱应用于细胞色素P-450,以分析蛋白质的二级结构。通过傅立叶自反卷积并拟合酰胺I' 区域 (1600-1700厘米-1) 中的红外光谱,我们估计了44% 无底物细胞色素P-450cam的 α-螺旋,31% β-折叠和18% 匝。在樟脑存在的情况下,获得了54% α-螺旋和310-螺旋,21% β-折叠和21% 匝,它们与53% α-螺旋,19% β-折叠和16% 匝的晶体学数据一致 [Poulos,T. L.,Finzel,b.c.,& Howard,A. J. (1987) J. Mol. Biol. 195,687-700]。细胞色素P-420cam以两种方式从无底物的细胞色素P-450cam产生 (i) 通过温度升高高达60 ℃ 和 (ii) 通过暴露于KSCN高达1.5 M。确定每种温度和KSCN浓度的二级结构组成,并将其与在出现1900年和2000厘米-1的铁配体CO拉伸振动带中观察到的变化进行比较。热诱导的细胞色素P-420具有19% 的 α-螺旋含量,53% 的 β-折叠含量,14% 转弯,以及来自蛋白质聚集体内的分子间氢键的5% 反平行 β-折叠。作为KSCN浓度的函数的细胞色素P-420的形成表明两种类型的细胞色素P-420。直到1 M KSCN,诱导的细胞色素P-420仅显示出很少的二级结构修饰,而在1.5 M KSCN处,观察到较大的变化,导致85% 的细胞色素P-420没有蛋白沉淀,并且含有30% 的 α-螺旋,48% 的 β-折叠和17% 转。铁配体CO拉伸区的红外光谱显示了几种用于细胞色素P-420的亚构象体。在细胞色素P-420形成过程中,与无底物细胞色素P-450cam-CO相比,CO拉伸模式向更高频率转移3-11厘米-1,主要特征约为1964厘米-1。
  • 【番红花ssp花粉萌发和柱头渗透的可逆抑制。用NO2,CO和O3气体熏蒸后的vernus (鸢尾科)。】 复制标题 收藏 收藏
    DOI:10.1055/s-2007-965246 复制DOI
    作者列表:Chichiriccò G,Picozzi P
    BACKGROUND & AIMS: :We assessed the pollen hydration, the pollen germination, and the stigma papilla penetration of CROCUS VERNUS subsp. VERNUS (Iridaceae) after 2 h fumigations with O (3), NO (2), and CO gases within humidified (90 - 100 % RH) box experiments. When the pollen and the pistil were separately fumigated, the pollen retained the capacity to emit a tube which penetrated papilla, and the stigma papillae retained the receptivity; when the pistils were first pollinated and then fumigated, the capacity of pollen to hydrate was not affected, but the germination was significantly reduced. The vulnerability to gases became evident at 0.3 ppm O (3), 0.2 ppm NO (2), and 0.5 ppm CO. The inhibition curves as a function of the gas concentrations were of an exponential type, and they saturated at 2 ppm NO (2), 25 ppm CO, and 0.5 ppm O (3), with germination percentages of 17 %, 27 %, and 60 %, respectively. Both the pollen germination and the papilla penetration were fully restored by prolonging for 60 - 90 min the incubation at 90 - 100 % RH, after the cessation of fumigations. The vulnerability of the pollen-papilla system is discussed.
    背景与目标: : 我们评估了番红花亚种的花粉水化,花粉萌发和柱头乳头渗透。在加湿 (90-100% RH) 盒实验中用O (3),NO (2) 和CO气体熏蒸2小时后的VERNUS (鸢尾科)。当花粉和雌蕊分别熏蒸时,花粉保留了穿透乳头的试管的能力,柱头乳头保留了感受性; 当雌蕊先授粉后熏蒸时,花粉的水合能力没有受到影响,但萌发明显降低。在0.3 ppm O (3) 、0.2 ppm NO (2) 和0.5 ppm CO时,对气体的脆弱性变得明显。作为气体浓度的函数的抑制曲线是指数型的,它们在2 ppm NO (2),25 ppm CO和0.5 ppm O (3) 下饱和,发芽率分别为17%,27% 和60%。熏蒸停止后,通过在90-100% RH下孵育60-90分钟,花粉萌发和乳头渗透都完全恢复。讨论了花粉-乳头系统的脆弱性。
  • 【接种量与底物比、底物混合比和接种量对草和猪粪分批共消化的影响。】 复制标题 收藏 收藏
    DOI:10.1016/j.biortech.2013.07.051 复制DOI
    作者列表:Dechrugsa S,Kantachote D,Chaiprapat S
    BACKGROUND & AIMS: :Biochemical methane potential (BMP) assay was conducted at 35 °C to evaluate the effects of inoculum to substrate ratio (ISR) and substrate mix ratio between para-grass and pig manure co-digesting using different inocula. Rubber latex digester (RLD) inoculum showed higher methanogenic activity (41.4 mL CH4/gVS) than pig farm digester (PFD) inoculum (37.3 mL CH4/gVS). However, the maximum methane yields, occurred at the highest para-grass mix ratio (G), were 369.6, 437.6, 465.9 and 442.6 mL CH4/gTSadded for RLD inoculum, versus 332.4, 475.0, 519.5 and 521.9 mL/gTSadded for PFD inoculum at ISR 1, 2, 3, and 4, respectively. HPr, HBu and HVa appeared at higher G, corresponding to substrate's higher biodegradability. Response surface indicated that higher ISR and G had a significantly positive impact on methane yield. It suggested the use of higher ISR, i.e. 3 or 4, for BMP assay of these co-substrates. Dominant species of fermentative bacteria in each inoculum was tested by DGGE.
    背景与目标: : 在35 °C下进行生化甲烷势 (BMP) 测定,以评估接种物与底物的比例 (ISR) 和底物混合比例在使用不同接种物的对位草和猪粪共同消化之间的影响。橡胶胶乳消化器 (RLD) 接种物显示出比猪场消化器 (PFD) 接种物 (37.3 mL CH4/gVS) 更高的产甲烷活性 (41.4 mL CH4/gVS)。然而,在最高的对草混合比 (G) 下,RLD接种物的最大甲烷产量为369.6、437.6、465.9和442.6 mL CH4/gts,而在ISR 1、2、3下,PFD接种物的最大甲烷产量为332.4、475.0、519.5和521.9 mL/gts,和4。HPr,HBu和HVa出现在较高的G处,对应于底物的较高的生物降解性。响应面表明,较高的ISR和G对甲烷产量有显着的积极影响。建议使用更高的ISR (即3或4) 进行这些共底物的BMP测定。通过DGGE测试了每个接种物中发酵细菌的优势种。
  • 【用于MRI的自动脑干共同配准 (ABC)。】 复制标题 收藏 收藏
    DOI:10.1016/j.neuroimage.2006.05.050 复制DOI
    作者列表:Napadow V,Dhond R,Kennedy D,Hui KK,Makris N
    BACKGROUND & AIMS: :Group data analysis in brainstem neuroimaging is predicated on accurate co-registration of anatomy. As the brainstem is comprised of many functionally heterogeneous nuclei densely situated adjacent to one another, relatively small errors in co-registration can manifest in increased variance or decreased sensitivity (or significance) in detecting activations. We have devised a 2-stage automated, reference mask guided registration technique (Automated Brainstem Co-registration, or ABC) for improved brainstem co-registration. Our approach utilized a brainstem mask dataset to weight an automated co-registration cost function. Our method was validated through measurement of RMS error at 12 manually defined landmarks. These landmarks were also used as guides for a secondary manual co-registration option, intended for outlier individuals that may not adequately co-register with our automated method. Our methodology was tested on 10 healthy human subjects and compared to traditional co-registration techniques (Talairach transform and automated affine transform to the MNI-152 template). We found that ABC had a significantly lower mean RMS error (1.22 +/- 0.39 mm) than Talairach transform (2.88 +/- 1.22 mm, mu +/- sigma) and the global affine (3.26 +/- 0.81 mm) method. Improved accuracy was also found for our manual-landmark-guided option (1.51 +/- 0.43 mm). Visualizing individual brainstem borders demonstrated more consistent and uniform overlap for ABC compared to traditional global co-registration techniques. Improved robustness (lower susceptibility to outliers) was demonstrated with ABC through lower inter-subject RMS error variance compared with traditional co-registration methods. The use of easily available and validated tools (AFNI and FSL) for this method should ease adoption by other investigators interested in brainstem data group analysis.
    背景与目标: : 脑干神经影像学中的组数据分析基于解剖结构的准确共配准。由于脑干由彼此密集相邻的许多功能异质核组成,因此在共同配准中相对较小的误差可能表现为检测激活的方差增加或敏感性降低 (或显着性)。我们设计了一种2阶段自动参考面罩引导的注册技术 (自动脑干共同注册或ABC),以改善脑干共同注册。我们的方法利用脑干掩模数据集对自动共同注册成本函数进行加权。我们的方法通过测量12个手动定义的地标上的均方根误差进行了验证。这些地标也被用作辅助手动共同注册选项的指南,该选项适用于可能无法与我们的自动方法充分共同注册的离群值个人。我们的方法在10名健康人类受试者上进行了测试,并与传统的共配准技术 (Talairach变换和自动仿射变换到MNI-152模板) 进行了比较。我们发现ABC的平均均方根误差 (1.22 +/-0.39毫米) 明显低于Talairach变换 (2.88 +/-1.22毫米,mu +/- sigma) 和全局仿射 (3.26 +/-0.81毫米) 方法。我们的手动地标引导选项 (1.51 +/-0.43毫米) 也提高了准确性。与传统的全球共配准技术相比,可视化单个脑干边界显示出ABC更加一致和统一的重叠。与传统的共配准方法相比,ABC通过较低的受试者间均方根误差方差证明了更高的鲁棒性 (对异常值的敏感性较低)。对于这种方法,使用易于获得和验证的工具 (AFNI和FSL) 应该可以简化对脑干数据组分析感兴趣的其他研究人员的采用。
  • 【量化共表达EGFR和HER2对HER活化和贩运的影响。】 复制标题 收藏 收藏
    DOI:10.1016/j.bbrc.2008.04.043 复制DOI
    作者列表:Shankaran H,Zhang Y,Opresko L,Resat H
    BACKGROUND & AIMS: :The human epidermal growth factor receptor (HER) system is an intricately regulated system that plays critical roles in development and tumorigenesis. Here, we apply integrated experimentation and modeling to analyze HER receptor activation in a panel of cell lines expressing endogenous levels of EGFR/HER1 and different levels of HER2. A mathematical model that includes the fundamental processes involved in receptor activation and trafficking was used to fit the experimental data, and values of the independent parameters for active receptor dimer formation affinities, trafficking rates and relative phosphorylation levels were estimated. Obtained parameter values quantitatively support the existing ideas on the effect of HER2 on EGFR dynamics, and enable us to predict the abundances of various phosphorylated receptor dimers in the cell lines.
    背景与目标: : 人类表皮生长因子受体 (HER) 系统是一个复杂的调节系统,在发育和肿瘤发生中起关键作用。在这里,我们应用综合实验和建模来分析表达内源性EGFR/HER1水平和不同水平her2的细胞系中的HER受体激活。使用包括受体激活和运输过程的基本过程的数学模型来拟合实验数据,并估算了活性受体二聚体形成亲和力,运输速率和相对磷酸化水平的独立参数值。获得的参数值定量地支持了关于HER2对EGFR动力学的影响的现有想法,并使我们能够预测细胞系中各种磷酸化受体二聚体的丰度。
  • 【麻醉的活跃研究领域: 麻醉文献的文献共引分析。】 复制标题 收藏 收藏
    DOI:10.1213/ane.0b013e31816d18a1 复制DOI
    作者列表:Jankovic MP,Kaufmann M,Kindler CH
    BACKGROUND & AIMS: BACKGROUND:The expansion of science has resulted in an increased information flow and in an exponentially growing number of connections between knowledge in different research fields. In this study, we used methods of scientometric analysis to obtain a conceptual network that forms the structure of active scientific research fields in anesthesia. METHODS:We extracted from the Web of Science (Institute for Scientific Information) all original articles (n = 3275) including their references (n = 79,972) that appeared in 2003 in all 23 journals listed in the Institute for Scientific Information Journal Citation Reports under the subject heading "Anesthesiology." After identification of highly cited references (> or = 5), pairs of co-cited references were created and grouped into uniformly structured clusters of documents using a single linkage and variable level clustering method. In addition, for each such cluster of documents, we identified corresponding front papers published in 2003, each of which co-cited at least two documents of the cluster core. Active anesthetic research fields were then named by examining the titles of the documents in both the established clusters and in their corresponding front papers. These research fields were sorted according to the proportion of recent documents in their cluster core (immediacy index) and were further analyzed. RESULTS:Forty-six current anesthetic research fields were identified. The research field named "ProSeal laryngeal mask airway" showed the highest immediacy index (100%) whereas the research fields "Experimental models of neuropathic pain" and "Volatile anesthetic-induced cardioprotection" exhibited the highest level of co-citation strength (level 9). The research field with the largest cluster core, containing 12 homogeneous papers, was "Postoperative nausea and vomiting." The journal Anesthesia & Analgesia published most front papers while Anesthesiology published most of the fundamental documents used as references in the front papers. CONCLUSIONS:Using co-citation analysis, we identified distinct homogenous clusters of highly cited documents representing 46 active current anesthetic research fields and determined multiple nets of knowledge among them.
    背景与目标:
  • 【使用新型共沉淀技术将双膦酸盐吸附到羟基磷灰石上,以增强骨生长。】 复制标题 收藏 收藏
    DOI:10.1002/jbm.a.30792 复制DOI
    作者列表:McLeod K,Anderson GI,Dutta NK,Smart RS,Voelcker NH,Sekel R,Kumar S
    BACKGROUND & AIMS: :Premature bone resorption and remodeling by osteoclasts can limit the longevity of implant fixation and recovery time. Orally administered bisphosphonates (BPs) have been used to inhibit osteoclast action at the implant/bone interface. Ideally, these should be delivered at the interface with the osteoblast-active hydroxyapatite (HA) for maximum effect. This investigation introduces a novel BP loading technique to achieve improved BP release from a simulated body fluid-grown HA (SBF-HA) with the aim of improving implant fixation. A solution co-precipitation technique incorporates the BP (pamidronate) into a thin SBF-HA coating. Surface analysis, using X-ray photoelectron spectroscopy (XPS), of the resultant coating was employed to confirm the presence of the adsorbed BP on the surface of SBF-HA. XPS analysis was also used to determine the optimal adsorption process. Osteoclast cell culture experiments confirmed the biological effectiveness of BP adsorption and proved that the pamidronate was biologically active, causing both decreased osteoclast numbers and decreased resorption.
    背景与目标: : 破骨细胞过早吸收和重塑会限制植入物固定的寿命和恢复时间。口服双膦酸盐 (BPs) 已用于抑制植入物/骨界面处的破骨细胞作用。理想情况下,这些应在与成骨细胞活性羟基磷灰石 (HA) 的界面处递送,以获得最大效果。这项研究引入了一种新颖的BP加载技术,以改善模拟体液生长的HA (sbf-ha) 中的BP释放,目的是改善植入物的固定。溶液共沉淀技术将BP (帕米膦酸盐) 结合到薄的sbf-ha涂层中。使用x射线光电子能谱 (XPS) 对所得涂层进行表面分析,以确认sbf-ha表面上存在吸附的BP。XPS分析也用于确定最佳吸附过程。破骨细胞培养实验证实了BP吸附的生物学有效性,并证明帕米膦酸盐具有生物活性,导致破骨细胞数量减少和吸收减少。
  • 【合并症抑郁症会影响糖尿病相关费用吗?来自低收入国家横断面调查的证据。】 复制标题 收藏 收藏
    DOI: 复制DOI
    作者列表:Chereches RM,Litan CM,Zlati AM,Bloom JR
    BACKGROUND & AIMS: AIMS OF THE STUDY:The economic implications of co-morbid depression in patients with chronic medical disorders have been studied mainly in high-income countries. However, the applicability of such findings in developing countries cannot be assumed. In the present study we estimate diabetes related costs and explore the link between depression and diabetes related costs in Romania. In this former communist country, the general perception of practitioners and policy-makers is that psychological issues are far less important than medical concerns for patients with diabetes, a perception that may lead to the misallocation of already scarce resources. METHODS:Data related to costs of diabetes care and to co-morbid depression were collected from a sample of 1,171 diabetes patients at the Nutrition and Diabetes Center in Cluj-Napoca, Romania, using the Diabetes Costs Questionnaire (DCQ) and the Patient Health Questionnaire 9 (PHQ9). The gathered data were subjected to a bivariate analysis of the depression-cost relationship, as well as a regression analysis in order to isolate the effect of depression on diabetes related costs from the effect of covariates. RESULTS:Direct and indirect diabetes related costs equally contributed to the total costs. The repartition of the cost burden between the public system and private agents is nearly equal as well. The bivariate analysis of the depression-cost relationship reveals statistically significant larger diabetes related costs for patients with major depression than for patients with minor depression, and the latter have larger diabetes related costs than patients free of depression symptoms. When the pure effect of depression on diabetes related costs was isolated by means of regression techniques, the provisional diagnosis of major depression was found to significantly increase diabetes related costs. DISCUSSION:The equal distribution of diabetes related costs between direct and indirect measures, as well as the cost burden equally split between the public system and private agents can be explained by the costs of medication and the costs associated with time lost by the non-compensated caregivers. Consistent with Romanian cultural traditions, most of the patients rely on their relatives in an informal diabetes caregiving market for assistance. Alongside depression, the multivariate analysis revealed that factors such as Hungarian ethnicity, income, and number of years since diagnosis also significantly contribute to diabetes related costs. IMPLICATIONS FOR HEALTH CARE PROVISION AND USE:Findings that depression increases diabetes related costs bear potential implications for health policies and health care provision (i.e., the effect of depression on costs can be minimized by adequate recognition and treatment). As such, screening and treatment of co-occurring depression in diabetes patients should become part of the diabetes treatment protocol, not only in Romania but in other Central and Eastern European countries as well.
    背景与目标:
  • 【在颗粒状生物质反应器中对过量的啤酒酵母进行厌氧共消化,以提高生物甲烷的产量。】 复制标题 收藏 收藏
    DOI:10.1016/j.biortech.2012.08.064 复制DOI
    作者列表:Zupančič GD,Skrjanec I,Logar RM
    BACKGROUND & AIMS: :The anaerobic co-digestion of brewery yeast using granular biomass was studied on the lab, pilot and full-scale. The study shows no adverse effects in the co-digestion of yeast and wastewater in concentrations up to 1.1 (v/v)%. In concentrations up to 2.3% the process is manageable; however, not advisable. In concentrations over 2.8% the process exhibits failure due to the overload with suspended solids. An average specific biogas production of 0.560 m(3)kg(-1) of volatile solids was achieved. Full-scale operation with 0.7% yeast concentration showed a 38.5% increase in the biogas production and a 26.2% increase in the organic loading rate, which resulted in an increase of the biomethane/natural-gas substitute ratio from 10% to 16%. The influence of the yeast addition on the structure of the microbial biomass showed up to 7% dissimilarity in the archaeal and a 32% dissimilarity in the bacterial biomass community, which did not present any difficulties.
    背景与目标: : 在实验室,中试和全规模上研究了使用颗粒状生物质对啤酒酵母的厌氧共消化。该研究表明,在浓度高达1.1 (v/v)% 的酵母和废水的共消化中没有不利影响。在高达2.3% 的浓度下,该过程是可管理的; 然而,不可取。在超过2.8% 的浓度下,由于悬浮固体的过载,该过程表现出失败。实现了0.560 m(3)kg(-1) 挥发性固体的平均比沼气产量。0.7% 酵母浓度的全面操作显示出沼气产量的38.5% 增加和有机负载率的26.2% 增加,这导致生物甲烷/天然气替代率从10% 增加到16%。添加酵母对微生物生物量结构的影响在古细菌中显示出7% 的差异,而在细菌生物量群落中显示出32% 的差异,这没有任何困难。

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