共查询到20条相似文献,搜索用时 15 毫秒
1.
Renée Roodbeen Jan C. M. van Hest 《BioEssays : news and reviews in molecular, cellular and developmental biology》2009,31(12):1299-1308
The recent development of RNA replicating protocells and capsules that enclose complex biosynthetic cascade reactions are encouraging signs that we are gradually getting better at mastering the complexity of biological systems. The road to truly cellular compartments is still very long, but concrete progress is being made. Compartmentalization is a crucial natural methodology to enable control over biological processes occurring within the living cell. In fact, compartmentalization has been considered by some theories to be instrumental in the creation of life. With the advancement of chemical biology, artificial compartments that can mimic the cell as a whole, or that can be regarded as cell organelles, have recently received much attention. The membrane between the inner and outer environment of the compartment has to meet specific requirements, such as semi‐permeability, to allow communication and molecular transport over the border. The membrane can either be built from natural constituents or from synthetic polymers, introducing robustness to the capsule. 相似文献
2.
Small molecules have long been used for the selective recognition of a wide range of analytes. The ability of these chemical receptors to recognise and bind to specific targets mimics certain biological processes (such as protein–substrate interactions) and has therefore attracted recent interest. Due to the abundance of biological molecules possessing polyhydroxy motifs, boronic acids—which form five-membered boronate esters with diols—have become increasingly popular in the synthesis of small chemical receptors. Their targets include biological materials and natural products including phosphatidylinositol bisphosphate, saccharides and polysaccharides, nucleic acids, metal ions and the neurotransmitter dopamine. This review will focus on the many ways in which small chemical receptors based on boronic acids have been used as biochemical tools for various purposes, including sensing and detection of analytes, interference in signalling pathways, enzyme inhibition and cell delivery systems. The most recent developments in each area will be highlighted. 相似文献
3.
de Castro Luana Silva de Souza Lopes Adriani Aragão Colares Lucas Palheta Leandra de Souza Menezes Mayko Fernandes Luciana Mendes Dunck Bárbara 《Limnology》2021,22(2):245-257
Limnology - Dams disrupt the longitudinal gradient and decrease the natural connectivity of lotic systems and change the physical, chemical, and biological compartments of the river environment.... 相似文献
4.
Self-assembly of reactive amphiphilic block copolymers as mimetics for biological membranes 总被引:1,自引:0,他引:1
Over the years, polymers have attracted a great deal of interest because they offer a unique platform for the development of materials in fields as diverse as biomedicine and packaging. Many of these purposes use polymers that had been developed for totally different applications. Recently, however, chemical tailoring and molecular and supramolecular control of the chemistry and, thus, the physical and biological response have become a key interest of many researchers. In particular, systems that operate in aqueous media have become an intensely researched field. This is mostly because many devices must be biocompatible, which implies that they have to function in aqueous solutions. Over the past few years, new approaches for mimicking cell surfaces, for generating biocompatible and bioactive drug delivery systems, and for directed targeting have been developed. One recent development is polymeric systems with an enhanced biofunctionality, such as amphiphilic block copolymers that can act as mimetics for biological membranes. Because there are virtually no limits to combinations of monomers, biological and synthetic building blocks, ligands, receptors, and other proteins, polymer hybrid materials show a great promise for applications in biomedicine and biotechnology. 相似文献
5.
Williams RJ 《Journal of inorganic biochemistry》2002,88(3-4):241-250
In this article we show why inorganic metal elements from the environment were an essential part of the origin of living aqueous systems of chemicals in flow. Unavoidably such systems have many closely fixed parameters, related to thermodynamic binding constants, for the interaction of the essential exchangeable inorganic metal elements with both inorganic and organic non-metal materials. The binding constants give rise to fixed free metal ion concentration profiles for different metal ions and ligands in the cytoplasm of all cells closely related to the Irving-Williams series. The amounts of bound elements depend on the organic molecules present as well as these free ion concentrations. This system must have predated coding which is probably only essential for reproductive life. Later evolution in changing chemical environments became based on the development of extra cytoplasmic compartments containing quite different energised free (and bound) element contents but in feed-back communication with the central primitive cytoplasm which changed little. Hence species multiplied late in evolution in large part due to the coupling with the altered inorganic environment. 相似文献
6.
Bruchez MP 《Current opinion in chemical biology》2011,15(6):775-780
Thirteen years after the demonstration of quantum dots as biological imaging agents, and nine years after the initial commercial introduction of bioconjugated quantum dots, the brightness and photostability of the quantum dots has enabled a range of investigations using single molecule tracking. These materials are being routinely utilized by a number of groups to track the dynamics of single molecules in reconstituted biophysical systems and on living cells, and are especially powerful for investigations of single molecules over long timescales with short exposure times and high pointing accuracy. New approaches are emerging where the quantum dots are used as 'hard-sphere' probes for intracellular compartments. Innovations in quantum dot surface modification are poised to substantially expand the utility of these materials. 相似文献
7.
8.
Engineered nanomaterials are commonly defined as materials with at least one dimension of 100 nanometers or less. Such materials typically possess nanostructure-dependent properties (e.g., chemical, mechanical, electrical, optical, magnetic, biological), which make them desiderable for commercial or medical application. However, these same properties may potentially lead to nanostructure-dependent biological activity that differs from and is not directly predicted by the bulk properties of the constitutive chemicals and compounds. Nanoparticles and nanomaterials can be on the same scale of living cells components, including proteins, nucleic acids, lipids and cellular organelles. When considering nanoparticles it must be asked how man-made nanostructures can interact with or influence biological systems. Carbon nanotubes (CNTs) are an example of carbon-based nanomaterial, which has won a huge spreading in nanotechnology. The incorporation of CNTs in living systems has raised many concerns because of their hydrophobicity and tendency to aggregate and accumulate into cells, organs, and tissues with dangerous effects. 相似文献
9.
H. E. Hart 《Bulletin of mathematical biology》1955,17(2):87-94
A method is developed for finding the transfer and localization rates and the volumes ofN compartment steady-state biological systems from experimental results. It is shown that a complete solution for certain systems
in which the rates and volumes remain constant and in which there is access to all compartments can be obtained by using a
single radioactive tracer. The information obtainable from experiments wherein some compartments are not accessible is analyzed
for mammillary and catenary systems. Conservative systems are handled as special cases in which the localization is zero while
anisotropic membranes separating compartments are shown to introduce no additional mathematical difficulty whenever all compartments
are accessible. The limitations on the use of this method of multi-compartment tracer analysis are briefly discussed.
Research supported by the Atomic Energy Commission, Contract AT (30-1)-1551. 相似文献
10.
11.
Martel S Clément JL Muller A Culcasi M Pietri S 《Bioorganic & medicinal chemistry》2002,10(5):1451-1458
With the aim to provide sensitive 31P NMR probes of intra- and extracellular pH gradients that may reach cellular acidic compartments in biological systems, new alpha-aminophosphonates were designed to meet basic requirements such as a low pK(a)s and a great chemical difference (Deltadelta(ab)) between the limiting 31P NMR chemical shifts in acidic (delta(a)) and basic (delta(b)) media. A series of six phosphorylated pyrrolidines and linear aminophosphonates were synthesized using aminophosphorylation reactions and were screened for cytotoxicity on cultured Müller cells. Among the compounds not being toxic under these conditions, three molecules were selected since they displayed the best in vitro (in several phosphate buffers and in a cytosol-like solution) properties as 31P NMR acidic pH markers, that is 3, 5 and 9, having the pK(a) values of 3.63, 5.89 and 5.66, respectively. The Deltadelta(ab) values of these pH markers were at least 3 times larger than that of standard 31P NMR probes, with a low sensitivity to ionic strength changes. From these data, it was proposed that 3, 5 and 9 could be used as reporting probes of subtle proton movements in acidic compartments, an area that still remains poorly investigated using non invasive 31P NMR methods. 相似文献
12.
“Bottom-up” approach for implementing nano/microstructure using biological and chemical interactions
Sang Woo Lee Woo-Jin Chang Rashid Bashir Yoon-Mo Koo 《Biotechnology and Bioprocess Engineering》2007,12(3):185-199
The “Bottom-up” approach for implementing nano/microstructure using biological self-assembled systems has been investigated
with tremendous interest by many researchers in the field of medical diagnostics, material synthesis, and nano/microelectronics.
As a result, the techniques for achieving these systems have been extensively explored in recent years. The developed or developing
techniques are based on many interdisciplinary areas such as biology, chemistry, physics, electrical engineering, mechanical
engineering, and so on. In this paper, we review the fundamentals behind the self-assembly concepts and describe the state
of art in the biological and chemical self-assembled systems for the implementation of nano/microstructures. These structures
described in the paper can be applied to the implementation of hybrid biosensors, biochip, novel bio-mimetic materials, and
nano/microelectronic devices. 相似文献
13.
Metals and other trace elements play an important role in many physiological processes in all biological systems. Characterization
of precise metal concentrations, their spatial distribution, and chemical speciation in individual cells and cell compartments
will provide much needed information to explore the metallome in health and disease. Synchrotron-based X-ray fluorescent microscopy
(SXRF) is the ideal tool to quantitatively measure trace elements with high sensitivity at high resolution. SXRF is based
on the intrinsic fluorescent properties of each element and is therefore element specific. Recent advances in synchrotron
technology and optimization of sample preparation have made it possible to image metals in mammalian tissue with submicron
resolution. In combination with correlative methods, SXRF can now, for example, determine the amount and oxidation state of
trace elements in intra-cellular compartments and identify cell-specific changes in the metal ion content during development
or disease progression. 相似文献
14.
Ramström O Bunyapaiboonsri T Lohmann S Lehn JM 《Biochimica et biophysica acta》2002,1572(2-3):178-186
Dynamic combinatorial chemistry (DCC) is a recently introduced supramolecular approach to generate libraries of chemical compounds based on reversible exchange processes. The building elements are spontaneously and reversibly assembled to virtually encompass all possible combinations, allowing for simple one-step generation of complex libraries. The method has been applied to a variety of combinatorial systems, ranging from synthetic models to materials science and drug discovery, and enables the establishment of adaptive processes due to the dynamic interchange of the library constituents and its evolution toward the best fit to the target. In particular, it has the potential to become a useful tool in the direct screening of ligands to a chosen receptor without extensive prior knowledge of the site structure, and several biological systems have been targeted. In the vast field of glycoscience, the concept may find special perspective in response to the highly complex nature of carbohydrate-protein interactions. This chapter summarises studies that have been performed using DCC in biological systems, with special emphasis on glycoscience. 相似文献
15.
The calculation of transfer rates in two compartment systems not in dynamic equilibrium 总被引:7,自引:1,他引:7
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Dynamic equilibrium in a biological system implies that the compartment under study does not change in size during the period of observation. In many biological systems there are, however, net changes with time and this report deals with the mathematical treatment necessary to calculate unequal rates of inflow and outflow. A method is presented for the calculation of transfer rates in a two compartment system when the rates of flow between these compartments are unequal but constant. Equations were developed to calculate the amount of material transported per unit time derived from measurements of specific activity and compartment size. The problems of (1) sampling from the pool and (2) the effects of analytical errors on the estimation of rate have been evaluated. An example has been presented in which the derived equations have been applied to a study of the simultaneous passage of sodium into and out of a permanently isolated loop of bowel. 相似文献
16.
Kasif Teker Ranjani Sirdeshmukh Kousik Sivakumar Shoaxin Lu Eric Wickstrom Hsin-Neng Wang Tuan Vo-Dinh Balaji Panchapakesan 《NanoBioTechnology》2005,1(2):171-182
Carbon nanotubes have many unique properties such as high surface area, hollow cavities, and excellent mechanical and electrical
properties. Interfacing carbon nanotubes with biological systems could lead to significant applications in various disease
diagnoses. Significant progress in interfacing carbon nanotubes with biological materials has been made in key areas such
as aqueous solubility, chemical and biological functionalization for biocompatibility and specificity, and electronic sensing
of proteins. In addition, the bioconjugated nanotubes combined with the sensitive nanotube-based electronic devices would
enable sensitive biosensors toward medical diagnostics. Furthermore, recent findings of improved cell membrane permeability
for carbon nanotubes would also expand medical applications to therapeutics using carbon nanotubes as carriers in gene delivery
systems. This article reviews the current trends in biological functionalization of carbon nanotubes and their potential applications
for breast cancer diagnostics. The article also reports the applications of confocal microscopy for use in understanding the
interactions of biological materials such as antibodies on carbon nanotubes that are specific to surface receptors in breast
cancer cells. Furthermore, a nanotube-field-effect transistor is demonstrated for electronic sensing of antibodies that are
specific to surface receptors in cancer cells. 相似文献
17.
Biofilm formation is a long-standing problem in ultrapure water and bioprocess fluid transport lines. The standard materials
used in these applications (316L stainless steel, polypropylene and glass) have long been known to be good surfaces for the
attachment of bacteria and other biological materials. To compare the relative tenacity of biofilms grown on materials used
in manufacturing processes, a model system for biofilm attachment was constructed that approximates the conditions in industrial
process systems. New fluorinated polymers were compared to the above materials by evaluating the surface area coverage of
bacterial populations on materials before and after mild chemical treatment. In addition, contact angle studies compared
the relative hydrophobicity of surfaces to suspensions of bacteria in growth media, and scanning electron microscopy and
atomic force microscopy studies were used to characterize surface smoothness and surface defects. Biofilm adherence to polymer-based
substrata was determined to be a function of both surface finish and surface chemistry. Specifically, materials that are
less chemically reactive, as indicated by higher contact angle, can have rougher surface finishes and still be amenable to
biofilm removal.
Received 20 March 1997/ Accepted in revised form 15 July 1997 相似文献
18.
Glesne DA 《Trends in biotechnology》2003,21(9):379-380
Recent discoveries arising from a combination of the biological, physical, chemical and materials sciences have resulted in the invention of numerous hybrid molecules that possess strengths inherent to each individual discipline. Nanocomposites that link biological molecules to inorganic moieties have led to a family of new reagents with unique capabilities for cellular imaging and macromolecule detection. A recent report has extended the applications of these hybrid molecules from their use as detection and scaffolding reagents into the realm of a biologically functional molecule. 相似文献
19.
Mádi A Kele Z Janáky T Punyiczki M Fésüs L 《Biochemical and biophysical research communications》2001,283(4):964-968
Transglutaminase-dependent cross-linking of proteins leads to protein polymerisation that confers stability as well as resistance to mechanical disruption and chemical attack. Various transglutaminases have been implicated in a wide range of biological phenomena occurring in both extracellular and intracellular compartments, but further clarification of the physiological role of these enzymes requires identification of possible substrate molecules. Here we report the detection, purification, and identification of two proteins, enolase and ATP synthase alpha subunit as glutamine donor protein substrates for the transglutaminase of the nematode Caenorhabditis elegans. 相似文献
20.
Britas Klemens Eriksson Tjisse van der Heide Johan van de Koppel Theunis Piersma Henk W. van der Veer Han Olff 《Ecosystems》2010,13(5):752-764
Shallow soft-sediment systems are mostly dominated by species that, by strongly affecting sediment dynamics, modify their
local environment. Such ecosystem engineering species can have either sediment-stabilizing or sediment-destabilizing effects
on tidal flats. They interplay with abiotic forcing conditions (wind, tide, nutrient inputs) in driving the community structure
and generating spatial heterogeneity, determining the composition of different communities of associated species, and thereby
affecting the channelling of energy through different compartments in the food web. This suggests that, depending on local
species composition, tidal flats may have conspicuously different geomorphology and biological functions under similar external
conditions. Here we use a historical reconstruction of benthic production in the Wadden Sea to construct a framework for the
relationships between human impacts, ecosystem engineering and sediment dynamics. We propose that increased sediment disturbances
by human exploitation interfere with biological controls of sediment dynamics, and thereby have shifted the dominant compartments
of both primary and secondary production in the Wadden Sea, transforming the intertidal from an internally regulated and spatially
heterogeneous, to an externally regulated and spatially homogenous system. This framework contributes to the general understanding
of the interaction between biological and environmental control of ecosystem functioning, and suggests a general framework
for predicting effects of human impacts on soft-bottom ecosystems. 相似文献