Identification of Putative Vaccine and Drug Targets against the Methicillin-Resistant Staphylococcus aureus by Reverse Vaccinology and Subtractive Genomics Approaches

Methicillin-resistant Staphylococcus aureus (MRSA) is an opportunistic pathogen and responsible for causing life-threatening infections. The emergence of hypervirulent and multidrug-resistant (MDR) S. aureus strains led to challenging issues in antibiotic therapy. Consequently, the morbidity and mortality rates caused by S. aureus infections have a substantial impact on health concerns. The current worldwide prevalence of MRSA infections highlights the need for long-lasting preventive measures and strategies. Unfortunately, effective measures are limited. In this study, we focus on the identification of vaccine candidates and drug target proteins against the 16 strains of MRSA using reverse vaccinology and subtractive genomics approaches. Using the reverse vaccinology approach, 4 putative antigenic proteins were identified; among these, PrsA and EssA proteins were found to be more promising vaccine candidates. We applied a molecular docking approach of selected 8 drug target proteins with the drug-like molecules, revealing that the ZINC4235426 as potential drug molecule with favorable interactions with the target active site residues of 5 drug target proteins viz., biotin protein ligase, HPr kinase/phosphorylase, thymidylate kinase, UDP-N-acetylmuramoyl-L-alanyl-D-glutamate-L-lysine ligase, and pantothenate synthetase. Thus, the identified proteins can be used for further rational drug or vaccine design to identify novel therapeutic agents for the treatment of multidrug-resistant staphylococcal infection.     

大核树枝状大分子的合成及其凝血、溶血性能研究

从 8 0年代中期开始 ,Ｔｏｍａｌｉａ、Ｎｅｗｋｏｍｅ、Ｆｒｅｃｈｅｔ等对树枝状大分子开展了卓有成效的研究 ,合成了多种结构的树枝状大分子[1 ] ,并对它们的应用进行了积极的探讨 .在数枝状大分子的合成方面 ,寻找新的多官能团引发核就是一个研究热点 ,例如采用大分子核 ,Ｆｒｅｃｈｅｔ等采用聚乙二醇作为核用收敛法合成了聚芳醚和聚芳酯树枝状大分子[2 ,3] ,为嵌段共聚增添了新的内容 .而Ｔｏｍａｌｉａ等以氨和乙二胺等小分子为核合成的聚酰胺 胺类树枝状大分子呈粘糊状[4] ,取样、称量等操作很麻烦 ,其应用也受到限制 .聚乙二醇无毒…     

微乳酸的缓蚀行为及其在岩心中的酸化效果

微乳酸的缓蚀行为及其在岩心中的酸化效果;土酸;微乳酸;油藏;缓蚀;填砂管;岩心     

Tb(III)‐modified properties of thermosensitive core–shell microspheres

A novel functional complex with the thermosensitive, magnetic, and fluorescent properties of poly(N‐isopropylacrylamide)‐grafted poly(N‐isopropylacrylamide‐co‐styrene) (PNNS) microspheres and Tb(III), PNNS–Tb(III), has been synthesized and characterized with different techniques. When PNNS with a core–shell structure interacts with Tb(III), Tb(III) mainly bonds to oxygen of the carbonyl groups of PNNS, forming the novel PNNS–Tb(III) complex. PNNS shows antiferromagnetic behavior, whereas the PNNS–Tb(III) complex exhibits paramagnetic behavior. The saturation magnetization is approximately 50 times higher than that of PNNS. The fluorescence intensity of the PNNS–Tb(III)complex at 545 nm is enhanced as much as 223 times in comparison with that of pure Tb(III). The novel magnetic and fluorescent properties of the PNNS–Tb(III) complex may be useful in biomedicine and fluorescence systems. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3121–3127, 2006     

A dynamic boundary value problem arising in the ecology of mangroves

We consider an evolution model describing the vertical movement of water and salt in a domain splitted in two parts: a water reservoir and a saturated porous medium below it, in which a continuous extraction of fresh water takes place (by the roots of mangroves). The problem is formulated in terms of a coupled system of partial differential equations for the salt concentration and the water flow in the porous medium, with a dynamic boundary condition which connects both subdomains.We study the existence and uniqueness of solutions, the stability of the trivial steady state solution, and the conditions for the root zone to reach, in finite time, the threshold value of salt concentration under which mangroves may live.     

Low-velocity impact of sandwich composite plates

In this paper we investigate impact and compression after impact properties of plain weave carbon fiber sandwich composites. Impact tests were conducted on different sample types to obtain information about absorbed energy and maximum impact force. The different samples consisted of foam-filled and hollow honeycomb cores with four-layer carbon fiber facesheets on one or both sides. The impact and compression after impact data provided valuable information to allow for comparisons between the different sample types. Also, the compression after impact tests were conducted in order to determine the reduction in compressive strength when comparing impacted to non-impacted samples. In conclusion, a two-degrees-of-freedom spring/mass model was compared to experimental results. The comparison helped illustrate the limitations of current impact theory. This paper was presented, in part, at a symposium honoring Dr Christian P. Burger, Novel Applications of Experimental Methods in Mechanics, held at the 2003 SEM Annual Conference and Exposition on Experimental and Applied Mechanics, June 2–4, 2003, Charlotte, North Carolina.     

HT－7托卡马克中等离子体平衡研究

本文解决了二维轴对称近似下带铁芯的托卡马克中等离子体平衡问题，计算了ＨＴ－７托卡马克中的等离子体平衡位形以及极向场系统的非线性电感和垂直场系数。最后应用Ｋｉｒｃｈｈｏｆｆ方程组和平衡垂直场公式得到了一组等离子体、加热场和垂直场线圈的电流波形的自洽曲线。     

Polyurethane/polyaniline and polyurethane‐poly(methyl methacrylate)/polyaniline conductive core‐shell particles: Preparation,morphology, and conductivity

Polyurethane/polyaniline (PU/PANI) and polyurethane‐poly(methyl methacrylate)/polyaniline (PU‐PMMA/PANI) conductive core‐shell particles were synthesized by a two‐stage polymerization process. The first stage was to produce a core of PU or PU‐PMMA via miniemulsion polymerization using sodium dodecyl sulfate (SDS) as the surfactant. The second stage was to synthesize the shell of polyaniline over the surface of core particles. Hydrogen chloride (HCl) and dodecyl benzenesulfonic acid (DBSA) were used as the dopant agents. Ammonium persulfate (APS) was used as the oxidant for the polymerization of ANI. Different concentrations of HCl, DBSA, and SDS would cause different conformations of PANI chains and thus different morphologies of PANI particles. UV–visible spectra revealed that the polaron band was blue‐shifted because of the more coiled conformation of PANI chains by increasing the concentration of DBSA. Besides, with a high concentration of DBSA, both spherical‐ and rod‐shape PANI particles were observed by transmission electron microscope, and the coverage of PANI particles onto the core surfaces was improved. The key point of formation of rod‐type PANI particles was that DBSA was served with a high concentration accompanied with the existence of HCl or SDS. The better coverage of PANI particles over the core surfaces by charging higher DBSA concentrations resulted in a higher conductivity of hybrid particles. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3902–3911, 2007     

An improved method of controlling rare earth incorporation in optical fiber

The process parameters involved at various stages of solution doping method for fabricating rare earth (RE) doped optical fiber have been systematically investigated to optimize the process conditions and achieve better control over RE incorporation. It is observed that the RE concentration, uniformity and the overall fiber quality are strongly influenced by the solution properties and dipping parameters. The soaking solution needs to be judiciously selected depending on the porous layer characteristics to improve the fiber quality and process efficiency. An interesting observation not hitherto reported is the influence of Al ion concentration in the solution on RE incorporation into the core. The investigation helps to obtain the optimum conditions necessary to produce fibers of given specification and achieve greater reproducibility.