Results 1 - 10 of 121
Results 1 - 10 of 121. Search took: 0.02 seconds
|Sort by: date | relevance|
[en] Works are presented on: molecular biophysics, photochemistry, photobiology and radiobiology. (M.A.)
[pt]Apresentam-se trabalhos em: biofisica molecular, fotoquimica, fotobiologia e radiobiologia. (M.A.)
[en] The problem of the origin of the asymmetry of biomolecules attracted many theoretical and experimental investigations. In spite of these studies the problem is still open. In this paper recent experiments which need careful repetitions are reviewed and some other experiments are suggested. The experiments involve studies related to different types of physical effects possibly causing asymmetry: weak interaction, Earth rotation, magnetic and electric fields, circularly polarized light, etc. (author)
[en] In this work, two theoretical approaches of the applications of quantum chemistry to biological macromolecules are presented: one with the intent of evaluating the interaction of this sistem to electrophilic compounds, and the other concerning the interaction of biological substrates to water molecules. (A.C.A.S.)
[pt]Neste trabalho sao apresentadas duas abordagens teoricas envolvendo a aplicacao de Quimica Quantica ao estudo de macromoleculas biologicas: uma delas no sentido de avaliar a interacao deste sistema com compostos eletrofilicos e a outra implicando interacoes de substratos biologicos com moleculas de agua. (A.C.A.S.)
[en] We have developed microfluidic chips for automating molecular biology processes such as gene ligation and gene transformation from nanolitre sample volumes with parallel architecture. Unlike conventional tube methods with cumbersome pipetting procedures, all processes, including metering of samples, ligation and transformation, were carried out in the microfluidic chips through pneumatic control of the nanofluid. The microfluidic devices presented here offer an illustration of some of the basic physics that arises when trying to miniaturize and automate biological techniques
[en] The results of the application of Moessbauer spectroscopy in biomedical research were briefly reviewed. The main directions of biomedical application and possibilities of Moessbauer spectroscopy to study the molecular nature of diseases were considered.
[en] Silver nanoparticles (AgNPs) have seen a recent spurt of use in varied fields of science. In this paper, we showed a novel application of AgNP as a promising microbial cell-lysis agent for genomic DNA isolation. We utilized chemically synthesized AgNPs for lysing bacterial cells to isolate their genomic DNA. The AgNPs efficiently lysed bacterial cells to yield good quality DNA that could be subsequently used for several molecular biology works. (paper)
[en] Green fluorescent protein (GFP), from the Pacific jellyfish A. victoria, has numerous uses in biotechnology and cell and molecular biology as a protein marker because of its specific chromophore, which is spontaneously created after proper protein folding. After formation, the chromophore is very stable and it remains intact during protein unfolding, meaning that the GFP unfolding process is not the reverse of the original folding reaction; i.e., the principles of microscopic reversibility do not apply. We have generated the mutant S65T/G67A-GFP, which is unable to efficiently form the cyclic chromophore, with the goal of investigating the folding, unfolding and competing aggregation of GFP under fully reversible conditions. Our studies have been performed in the presence of guanidinium hydrochloride (GdnHCl). The GFP conformation was monitored using intrinsic tryptophan fluorescence, and fluorescence of 1,1'-bis(4-anilino-5-naphthalenesulphonic acid) (bis-ANS). Light scattering was used to follow GFP aggregation. We conclude from these fluorescence measurements that S65T/G67A-GFP folding is largely reversible. During equilibrium folding, the first step is the formation of a molten globule, prone to aggregation
[en] High speed imaging by atomic force microscopy (AFM) allows one to directly observe the dynamic behavior of a sample surface immersed in liquid media; thus, it has been considered to be an indispensable tool for nanobiotechnology and is used in many research fields, including molecular biology and surface science. For real-time observation of a certain behavior, the high speed imaging technique should be accompanied with a high resolution imaging technique to identify target materials. To improve the image quality at a high scanning rate, we developed a variable-controlled fast scanning method, which originated from the modified squeeze-drag superposition model in liquid media. A collection of non-distorted images was accomplished after proper modification of the operating conditions in a viscous fluid, via the simple handling of loading force and cantilever length. Consequently, a speeded-up AFM imaging process was achieved in the liquid environment at up to 200 μm s-1, without attachment of additional devices. The reliability of the proposed method was verified by the characterization of a grating sample immersed in three types of liquid media. In addition, the results were visualized for elastic biomolecules submerged in a liquid with high kinematic viscosity.
[en] Several classes of biological molecules that transform chemical energy into mechanical work are known as motor proteins or molecular motors. These nanometer-sized machines operate in noisy stochastic isothermal environments, strongly supporting fundamental cellular processes such as the transfer of genetic information, transport, organization and functioning. In the past two decades motor proteins have become a subject of intense research efforts, aimed at uncovering the fundamental principles and mechanisms of molecular motor dynamics. In this review, we critically discuss recent progress in experimental and theoretical studies on motor proteins. Our focus is on analyzing fundamental concepts and ideas that have been utilized to explain the non-equilibrium nature and mechanisms of molecular motors. (topical review)