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The morphology of bacteriophage-like particles from the strict anaerobe Fusobacterium symbiosum is described. Attempts to demonstrate plaque formation on the host strain of F. symbiosum and other related species were unsuccessful. 相似文献
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Bacteriophage-like particles were found in the supernatant fluids of Escherichia coli O111a and O111:B(4). Caution is urged in the study of deoxyribonucleic acid synthesis and replication in these strains. 相似文献
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Efficient drug delivery to the eye remains a challenging task for pharmaceutical scientists. Due to the various anatomical barriers and the clearance mechanisms prevailing in the eye, conventional drug delivery systems, such as eye drop solutions, suffer from low bioavailability. More invasive methods, such as intravitreal injections and implants, cause adverse effects in the eye. Recently, an increasing number of scientists have turned to nanomaterial-based drug delivery systems to address the challenges faced by conventional methods. This paper highlights recent applications of various nanomaterials, such as polymeric micelles, hydrogels, liposomes, niosomes, dendrimers, and cyclodextrins as ocular drug delivery systems to enhance the bioavailability of ocular therapeutic agents. 相似文献
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骨质疏松症是一种以骨密度减低和骨结构改变为特征的代谢性骨病,目前的治疗方法不能有效解决其引起的骨量减低及其增加的骨折风险。纳米材料由于其独特的性能已被广泛应用于骨组织工程中,本文归纳了几种纳米材料研究的新进展以及其在骨质疏松中的应用前景。 相似文献
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检测纳米材料毒性的若干实验方法 总被引:1,自引:0,他引:1
纳米材料进入生命体和环境以后可能带来的生物安全问题需要定量的测定。现有的检测纳米材料生物安全性的方法大致可分为体内和体外实验两种,但是还没有证据表明既有的某个方法单独能作为一种检测所有纳米材料毒性的通用方法,也没有证据表明这些方法合在一起就能全面评估纳米材料的生物安全性。本文在总结既有的若干方法的同时,报道了一种基于rpsL基因的复制保真性来定量检测纳米材料毒性的方法。纳米材料对rpsL基因的体内体外复制过程保真性的影响均可方便地定量测定。 相似文献
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A variety of organic and inorganic nanomaterials with dimensions below several hundred nanometers are recently emerging as
promising tools for cancer therapeutic and diagnostic applications due to their unique characteristics of passive tumor targeting.
A wide range of nanomedicine platforms such as polymeric micelles, liposomes, dendrimers, and polymeric nanoparticles have
been extensively explored for targeted delivery of anti-cancer agents, because they can accumulate in the solid tumor site
via leaky tumor vascular structures, thereby selectively delivering therapeutic payloads into the desired tumor tissue. In
recent years, nanoscale delivery vehicles for small interfering RNA (siRNA) have been also developed as effective therapeutic
approaches to treat cancer. Furthermore, rationally designed multi-functional surface modification of these nanomaterials
with cancer targeting moieties, protective polymers, and imaging agents can lead to fabrication versatile theragnostic nanosystems
that allow simultaneous cancer therapy and diagnosis. This review highlights the current state and future prospects of diverse
biomedical nanomaterials for cancer therapy and imaging. 相似文献
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Dong-Jiang Tang Yuen-Man Lam Yu-Lam Siu Chi-Hong Lam Shui-Ling Chu J. S. Malik Peiris Philippe Buchy Béatrice Nal Roberto Bruzzone 《PloS one》2012,7(11)
Background
Serological studies for influenza infection and vaccine response often involve microneutralization and hemagglutination inhibition assays to evaluate neutralizing antibodies against human and avian influenza viruses, including H5N1. We have previously characterized lentiviral particles pseudotyped with H5-HA (H5pp) and validated an H5pp-based assay as a safe alternative for high-throughput serological studies in BSL-2 facilities. Here we show that H5-HAs from different clades do not always give rise to efficient production of H5pp and the underlying mechanisms are addressed.Methodology/Findings
We have carried out mutational analysis to delineate the molecular determinants responsible for efficient packaging of HA from A/Cambodia/40808/2005 (H5Cam) and A/Anhui/1/2005 (H5Anh) into H5pp. Our results demonstrate that a single A134V mutation in the 130-loop of the receptor binding domain is sufficient to render H5Anh the ability to generate H5Anh-pp efficiently, whereas the reverse V134A mutation greatly hampers production of H5Cam-pp. Although protein expression in total cell lysates is similar for H5Anh and H5Cam, cell surface expression of H5Cam is detected at a significantly higher level than that of H5Anh. We further demonstrate by several independent lines of evidence that the behaviour of H5Anh can be explained by a stronger binding to sialic acid receptors implicating residue 134.Conclusions
We have identified a single A134V mutation as the molecular determinant in H5-HA for efficient incorporation into H5pp envelope and delineated the underlying mechanism. The reduced binding to sialic acid receptors as a result of the A134V mutation not only exerts a critical influence in pseudotyping efficiency of H5-HA, but has also an impact at the whole virus level. Because A134V substitution has been reported as a naturally occurring mutation in human host, our results may have implications for the understanding of human host adaptation of avian influenza H5N1 viruses. 相似文献11.
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核酸适配体(aptamer)是一类由指数富集配体系统进化(systematic evolution of ligands by exponential enrichment,SELEX)技术筛选出的RNA和单链DNA寡核苷酸片段。因其非同寻常的分子识别能力及结构特性,核酸适配体已经成为最具有应用前景的生物分子之一,综述了核酸适配体结合不同的纳米材料在肿瘤靶向治疗上的应用。 相似文献
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The reaction of cells to varying topographic surfaces has been investigated ever since the beginnings of cell culture technology,
as these features influence the cells principle behaviours such as adhesion, spreading, morphology, motility and proliferation.
Interest in this aspect of cell biology was renewed when advanced fabrication methods became more widespread. This paper tries
to briefly summarise the current state of knowledge regarding the use of nanostructured surfaces for cell- and tissue engineering. 相似文献
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Michael Boska Yutong Liu Mariano Uberti Balarininvasa R. Sajja Shantanu Balkundi JoEllyn McMillan Howard E. Gendelman 《Journal of visualized experiments : JoVE》2010,(46)
Nanomedications can be carried by blood borne monocyte-macrophages into the reticuloendothelial system (RES; spleen, liver, lymph nodes) and to end organs. The latter include the lung, RES, and brain and are operative during human immunodeficiency virus type one (HIV-1) infection. Macrophage entry into tissues is notable in areas of active HIV-1 replication and sites of inflammation. In order to assess the potential of macrophages as nanocarriers, superparamagnetic iron-oxide and/or drug laden particles coated with surfactants were parenterally injected into HIV-1 encephalitic mice. This was done to quantitatively assess particle and drug biodistribution. Magnetic resonance imaging (MRI) test results were validated by histological coregistration and enhanced image processing. End organ disease as typified by altered brain histology were assessed by MRI. The demonstration of robust migration of nanoformulations into areas of focal encephalitis provides ''proof of concept for the use of advanced bioimaging techniques to monitor macrophage migration. Importantly, histopathological aberrations in brain correlate with bioimaging parameters making the general utility of MRI in studies of cell distribution in disease feasible. We posit that using such methods can provide a real time index of disease burden and therapeutic efficacy with translational potential to humans. 相似文献
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2D nanomaterials provide numerous fascinating properties, such as abundant active surfaces and open ion diffusion channels, which enable fast transport and storage of lithium ions and beyond. However, decreased active surfaces, prolonged ion transport pathway, and sluggish ion transport kinetics caused by self‐restacking of 2D nanomaterials during electrode assembly remain a major challenge to build high‐performance energy storage devices with simultaneously maximized energy and power density as well as long cycle life. To address the above challenge, porosity (or hole) engineering in 2D nanomaterials has become a promising strategy to enable porous 2D nanomaterials with synergetic features combining both 2D nanomaterials and porous architectures. Herein, recent important progress on porous/holey 2D nanomaterials for electrochemical energy storage is reviewed, starting with the introduction of synthetic strategies of porous/holey 2D nanomaterials, followed by critical discussion of design rule and their advantageous features. Thereafter, representative work on porous/holey 2D nanomaterials for electrochemical capacitors, lithium‐ion and sodium‐ion batteries, and other emerging battery technologies (lithium‐sulfur and metal‐air batteries) are presented. The article concludes with perspectives on the future directions for porous/holey 2D nanomaterial in energy storage and conversion applications. 相似文献
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Biology Bulletin - Summaries of recent advances in the development of biosensors (BSs) and biofuel cells (BFCs) using nanomaterials (NMs) are presented. NMs are considered as elements that can... 相似文献
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Plasmonic nanomaterials, especially Au and Ag nanomaterials, have shown attractive physicochemical properties, such as easy functionalization and tunable optical bands. The development of this active subfield paves the way to the fascinating biosensing platforms. In recent years, plasmonic nanomaterials–based sensors have been extensively investigated because they are useful for genetic diseases, biological processes, devices, and cell imaging. In this account, a brief introduction of the development of optical biosensors based on DNA‐functionalized plasmonic nanomaterials is presented. Then the common strategies for the application of the optical sensors are summarized, including colorimetry, fluorescence, localized surface plasmon resonance, and surface‐enhanced resonance scattering detection. The focus is on the fundamental aspect of detection methods, and then a few examples of each method are highlighted. Finally, the opportunities and challenges for the plasmonic nanomaterials–based biosensing are discussed with the development of modern technologies. 相似文献
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At the end of 1980s, regions of the polypeptide chain of bacterial flagella subunits (flagellins) responsible for different properties of these protein polymers were identified by structural studies. It was found that the N-and C-terminal regions are responsible for the polymerization properties of subunits, and the central region is responsible for antigenic properties of the flagellum. Soon after that, it was proposed to use variability of the central flagellin domain for directed modification to impart new properties to the flagellum surface. Such studies of flagella and other polymeric structures of bacterial origin thrived. However bacterial polymers have some shortcomings, mainly their instability to dissociating effects. This shortcoming is absent in archaeal flagella. A limiting factor was the lack of the three-dimensional structure of archaeal flagellins. A method was developed that allowed modifying flagella of the halophilic archaeon Halobacterium salinarum in a peptide that connects positively charged ions. Later, corresponding procedures were used that allowed preparing the anode material for a lithiumion battery whose characteristics 4-5-fold exceeded those of batteries commonly used in industrial production. We describe other advantages of archaeal flagella over bacterial analogs when used in nanotechnology. 相似文献
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