Amphotericin B Resistance Assay for the Detection of Cholesterol Biosynthesis Inhibitors

Three different types of cholesterol biosynthesis inhibitors, lovastatin, ketoconazole, and 25-hydroxycholesterol, showed their respective resistance against amphotericin B (AmB) cytotoxicity in Chinese hamster ovary (CHO)-K1 cells. The negative correlation between the acquisition of AmB resistance and the decrease of cellular cholesterol content by the inhibitor was confirmed.     

Formation of di-d-fructofuranose-1,2′:2,1′-dianhydride by three novel inulin fructotransferases from the Nocardiaceae family

In this work, three novel genes encoding di-d-fructofuranose-1,2′:2,1′-dianhydride (DFA I)-forming inulin fructotransferases (IFTases) from Nocardiaceae family, including Nocardioides luteus, Nocardioides sp. JS614, and Nocardioidaceae bacterium Broad-1, were cloned and expressed in Escherichia coli. The recombinant IFTases from N. luteus (NoluIFTase), Nocardioides sp. JS614 (NospIFTase), and N. bacterium Broad-1 (NobaIFTase) were purified, identified, and characterized. SDS-PAGE analysis showed that they had molecular weights of approximately 41–42 kDa, while gel filtration analysis indicated that their native molecular weights ranged from 50 to 62 kDa, suggesting that the three enzymes may be monomers. Their optimum pH values ranged from 5.5 to 6.0, similar to other DFA I-forming IFTases or di-d-fructofuranose-1,2′:2,3′-dianhydride (DFA III)-forming IFTases. NoluIFTase, NospIFTase, and NobaIFTase exhibited maximal activities at 55 °C, 50 °C, and 45 °C and were stable at 70 °C (for 15 min), 70 °C (187 min), and 55 °C (239 min), respectively. Furthermore, by comparing with our previously reported DFA I-forming IFTase, namely CcIFTase, a probable mechanism for the formation of DFA I by the three new enzymes was speculated, and CcIFTase will be selected for future structural resolution to illustrate the catalytic mechanism of DFA I-forming IFTases toward inulin.     

Viruses and asthma

Background

Viral respiratory infection has long been known to influence the occurrence of asthma exacerbations. Over the last 20 years much effort has been put into clarifying the role that viral respiratory infections play in the eventual development of asthma.

Scope of review

In this review we give a general background of the role of viruses in the processes of asthma exacerbation and asthma induction. We review recent additions to the literature in the last 3 years with particular focus on clinical and epidemiologic investigations of influenza, rhinovirus, bocavirus, respiratory syncytial virus, and metapneumovirus.

Major conclusions

The development of asthma emerges from a complex interaction of genetic predisposition and environmental factors with viral infection likely playing a significant role in the effect of environment on asthma inception. This article is part of a Special Issue entitled: Biochemistry of Asthma.

General significance

Further understanding of the role that viruses play in asthma exacerbation and inception will contribute to decreased asthma morbidity in the future. This article is part of a Special Issue entitled: Biochemistry of Asthma.     

基于几何形态学的北二星蝽种内形态差异分析(半翅目： 蝽科)(英文)

【目的】北二星蝽Eysarcoris aeneus是一种广泛分布于古北区的重要农业害虫,可危害多种经济作物。其刺肩型和钝肩型前胸背板后侧角长度存在差异,暗示其种内变异的存在。【方法】基于几何形态学的多元回归分析(multivariate regression)、主成分分析(principal component analysis, PCA)、典型变量分析(canonical variate analysis, CVA)和判别函数分析(discriminant function analysis, DFA),对采集于中国19个地区的142头标本(98头北二星蝽标本和44头作为外群的广二星蝽E.ventralis标本)的前翅、后翅、头和小盾片4个性状进行分析比较,研究北二星蝽钝肩型和刺肩型之间的形态变异。【结果】对于所研究的4个性状来说,北二星蝽钝肩型和刺肩型标本间均未检测到异速生长的存在。主成分分析中,钝肩型和刺肩型的标本均有重叠,典型变量分析则显示它们之间存在显著差异(马氏距离和普氏距离的P值均小于0.01)。判别函数分析显示,依据这4个性状两型样本间的正确判别率在67%~89%之间。【结论】结果表明,前翅、后翅、头和小盾片都可以作为北二星蝽钝肩型和刺肩型之间形态变异的评价指标,小盾片特征具有最高水平的鉴别价值;对于所研究的这4个性状来说,北二星蝽钝肩型和刺肩型之间都表现出显著的形状差异,而它们的质心距离差异不显著,说明相对于体型大小差异分析,形状差异分析能更灵敏地揭示谱系间的变异。本研究表明几何形态学可以有效地描述北二星蝽的种内形态变异,为蝽类昆虫种内变异的研究奠定了基础。     

Structure of Lennard–Jones fluid near large spherical particles: further test of the “universality” of adjustable parameter in perturbation density functional theory

Grand canonical Monte Carlo simulation is used to study the density profiles of Lennard–Jones (LJ) fluid next to a large hard sphere (mimicking a colloidal particle) of various sizes. The LJ fluid in the inhomogeneous system thus maintains equilibrium with the bulk LJ fluid. The chosen density and potential parameters for the bulk fluid correspond to the conditions situated at “dangerous” regions of the phase diagram, i.e. near the critical temperature or close to the gas–liquid coexistence curve. The aim of present extensive simulations is to provide exact data for the broad range of the bulk parameters against which the “universality” of adjustable parameter associated with a perturbation density functional approximation (DFA) can be tested. Here the term “universality” means independence of this parameter on the particular external field responsible for the generation of a non-uniform density profile of the fluid. It is shown that the “universality” of this parameter associated with a third order+second order perturbation DFA holds also in the present case of a large spherical particle as a source of external potential, similarly as established in previous studies dealing with other interaction potential and other external fields [J. Chem. Phys., 122, 064503 (2005); J. Chem. Phys., 123 124708 (2005)]. This DFA can be used as input into a recently proposed framework for the calculation of interparticle potential of mean force (PMF).