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1.
Summary Arylsulfatase activities in biological materials are too low to be detected by the methods available hitherto. A sensitive and specific assay method for arylsulfatase A (AS-A) has been developed in the present study. Ascorbate-2-sulfate is known to be a specific natural substrate of AS-A; the ascorbic acid liberated by the action of AS-A was quantitatively determined using HPLC equipped with an amperometric detector. The method was used to analyze the activity of AS-A in biological materials.  相似文献   

2.
Summary A method for fluorometric estimation of micro-amounts of calcium (about 10 nEq./sample) in biological materials using calcein as indicator. Its applicability to heart muscle specimens (6–100 mg wet weight) and its limitation by interfering substances are described.  相似文献   

3.
Summary A fluid-measuring tube with separate cell measuring and counting chamber, is described with which metabolic transposition of small amounts of biological materials can be examined within an enclosed system. Tests were carried out on the course of the expiration of sucrose through phylloxers weighing 20 mg, and also on the fixation in the dark of CO2 by 8 green grapes. Tests were also carreied out on the expiration of sucrose and malic acid by yeast in fermentation. The course of metabolism can easily be seen by means of the radioactivity curves.  相似文献   

4.
Metabolomics is an analytical technique that investigates the small biochemical molecules present within a biological sample isolated from a plant, animal, or cultured cells. It can be an extremely powerful tool in elucidating the specific metabolic changes within a biological system in response to an environmental challenge such as disease, infection, drugs, or toxins. A historically difficult step in the metabolomics pipeline is in data interpretation to a meaningful biological context, for such high-variability biological samples and in untargeted metabolomics studies that are hypothesis-generating by design. One way to achieve stronger biological context of metabolomic data is via the use of cultured cell models, particularly for mammalian biological systems. The benefits of in vitro metabolomics include a much greater control of external variables and no ethical concerns. The current concerns are with inconsistencies in experimental procedures and level of reporting standards between different studies. This review discusses some of these discrepancies between recent studies, such as metabolite extraction and data normalisation. The aim of this review is to highlight the importance of a standardised experimental approach to any cultured cell metabolomics study and suggests an example procedure fully inclusive of information that should be disclosed in regard to the cell type/s used and their culture conditions. Metabolomics of cultured cells has the potential to uncover previously unknown information about cell biology, functions and response mechanisms, and so the accurate biological interpretation of the data produced and its ability to be compared to other studies should be considered vitally important.  相似文献   

5.
Summary A method for preparation of electron microscopic specimens by ultrafiltration can be used for bacteriophages, mycoplasma, and fragile biological particles, especially from solutions containing low concentrations of these particles and when it is necessary to remove also macromolecules up to a certain size.  相似文献   

6.
E Tal  S Savion  M Abraham  N Hanna 《Experientia》1978,34(4):536-537
A sensitive and specific immunofluorescent method for identification of thyrotropic cells was developed. The TSH-producing cells were found to be heterogenic in their morphology and intensity of staining.  相似文献   

7.
Summary A sensitive and specific immunofluorescent method for identification of thyrotropic cells was developed. The TSH-producing cells were found to be heterogenic in their morphology and intensity of staining.  相似文献   

8.
Summary It was found that the distribution pattern of calcium oxalate monohydrate present in the leaves of gymnosperms growing in Japan is classified into 2 groups by the technique of the low-temperature plasma ashing method for biological tissues.Acknowledgment. The author expresses his best thanks to the staff of the Koishikawa Botanical Garden, University of Tokyo, for the donation of valuable plant materials for the present work.  相似文献   

9.
Reactive oxygen species (ROS) production by the phagocyte NADPH oxidase is essential for host defenses against pathogens. ROS are very reactive with biological molecules such as lipids, proteins and DNA, potentially resulting in cell dysfunction and tissue insult. Excessive NADPH oxidase activation and ROS overproduction are believed to participate in disorders such as joint, lung, vascular and intestinal inflammation. NADPH oxidase is a complex enzyme composed of six proteins: gp91phox (renamed NOX2), p22phox, p47phox, p67phox, p40phox and Rac1/2. Inhibitors of this enzyme could be beneficial, by limiting ROS production and inappropriate inflammation. A few small non-peptide inhibitors of NADPH oxidase are currently used to inhibit ROS production, but they lack specificity as they inhibit NADPH oxidase homologues or other unrelated enzymes. Peptide inhibitors that target a specific sequence of NADPH oxidase components could be more specific than small molecules. Here we review peptide-based inhibitors, with particular focus on a molecule derived from gp91phox/NOX2 and p47phox, and discuss their possible use as specific phagocyte NADPH oxidase inhibitors.  相似文献   

10.
    
Summary Pancreatic exocrine secretion in dogs—either normal or induced by dicarnitine—contains high amounts of carnitine. This finding suggests that the biological action of dicarnitine might not only occur through the parasympathetic system but might also be due to a more specific action of carnitine itself.  相似文献   

11.
Nanoparticles (NPs) comprised of nanoengineered complexes are providing new opportunities for enabling targeted delivery of a range of therapeutics and combinations. A range of functionalities can be included within a nanoparticle complex, including surface chemistry that allows attachment of cell-specific ligands for targeted delivery, surface coatings to increase circulation times for enhanced bioavailability, specific materials on the surface or in the nanoparticle core that enable storage of a therapeutic cargo until the target site is reached, and materials sensitive to local or remote actuation cues that allow controlled delivery of therapeutics to the target cells. However, despite the potential benefits of NPs as smart drug delivery and diagnostic systems, much research is still required to evaluate potential toxicity issues related to the chemical properties of NP materials, as well as their size and shape. The need to validate each NP for safety and efficacy with each therapeutic compound or combination of therapeutics is an enormous challenge, which forces industry to focus mainly on those nanoparticle materials where data on safety and efficacy already exists, i.e., predominantly polymer NPs. However, the enhanced functionality affordable by inclusion of metallic materials as part of nanoengineered particles provides a wealth of new opportunity for innovation and new, more effective, and safer therapeutics for applications such as cancer and cardiovascular diseases, which require selective targeting of the therapeutic to maximize effectiveness while avoiding adverse effects on non-target tissues.  相似文献   

12.
Study of molecular events in cells by fluorescence correlation spectroscopy   总被引:6,自引:0,他引:6  
To understand processes in a living cell, sophisticated and creative approaches are required that can be used for gathering quantitative information about large number of components interacting across temporal and spatial scales without major disruption of the integral network of processes. A physical method of analysis that can meet these requirements is fluorescence correlation spectroscopy (FCS), which is an ultrasensitive and non-invasive detection method capable of single-molecule and real-time resolution. Since its introduction about 3 decades ago, this until recently emerging technology has reached maturity. As commercially built equipment is now available, FCS is extensively applied for extracting biological information from living cells unattainable by other methods, and new biological concepts are formulated based on findings by FCS. In this review, we focus on examples in the field of molecular cellular biology. The versatility of the technique in this field is illustrated in studies of single-molecule dynamics and conformational flexibility of proteins, and the relevance of conformational flexibility for biological functions regarding the multispecificity of antibodies, modulation of activity of C5a receptors in clathrin-mediated endocytosis and multiplicity of functional responses mediated by the p53 tumor suppressor protein; quantitative characterization of physicochemical properties of the cellular interior; protein trafficking; and ligand-receptor interactions. FCS can also be used to study cell-to-cell communication, here exemplified by clustering of apoptotic cells via bystander killing by hydrogen peroxide.Received 15 July 2004; received after revision 13 October 2004; accepted 12 November 2004  相似文献   

13.
建立了反相高效液相色谱(Reverse Phaseliquid Chromatography,RP—HPLC)测定庆大霉素效价的方法,结合管碟法所做的生物效价进行比较,其相关度R。:0.9823,RSD:1.29,证明RP—HPLC可直接测定庆大霉素的效价,从而解决了生测效价程序复杂,人为误差大的问题。RP—HPLC测定方法:采用岛津高效液相色谱SPD.IOAVP、UV.VIS、LC.IOATVP,PepMapC18Trs4.6×150mmSilicaC18(5μm300A)PhenomenexODS色谱柱,流动相MILLI-Q水:冰醋酸:甲醇(比例为25:5:70)配置0.02mol/L庚烷磺酸钠溶液,流速1.0mL/min,检测波长330nm,检测灵敏度0.020AUFS,柱温为室温,进样量20μL,在10min内可对样品液中C1、C1a、C2a、C24种物质同时进行定性定量测定。  相似文献   

14.
S Ghosh 《Experientia》1976,32(5):673-674
The use of formaldehyde-Schiff's reagent as a nucleolar stain has been described. Using different digestion procedures, it was confirmed that the stain is specific for RNA. It can be suitably used as a nucleolar stain, particularly in plant materials after a short TCA extraction, which probably extracts the nonbound RNA.  相似文献   

15.
Summary The use of formaldehyde-Schiff's reagent as a nucleolar stain has been described. Using different digestion procedures, it was confirmed that the stain is specific for RNA. It can be suitably used as a nucleolar stain, particularly in plant materials after a short TCA extraction, which probably extracts the nonbound RNA.  相似文献   

16.
A A Gurwitsch 《Experientia》1988,44(7):545-550
The 'miracle of caryokinesis' was the starting point that stimulated Alexander G. Gurwitsch to carry out his famous 'mitogenetic' experiments in 1923. The results obtained confirmed his hypothesis of a weak radiation from cells, which is able to trigger the growth of other cells. Extensive experimental work within the first two decades after this discovery indicated that the problem of mitogenetic radiation is generally related to the biological significance of UV-radiation. Both 'energetic' and 'informational' aspects have to be considered, namely radiation effective in activating molecules, and that involved in arranging them into larger units. The molecular organization of biological structures is evidently governed by nonequilibrium conditions needing the uptake or emission of radiation. These concepts of A. G. Gurwitsch can be linked with modern approaches based on hypotheses of coherence in biology, 'synergetics' and 'dissipative structures'. However, the question of causal interrelationships between this part of non-equilibrium radiation and biological matter on different levels of evolution has to be solved now.  相似文献   

17.
Summary A simple and time saving numerical method is described permitting the rapid determination of mother to daughter ratios in biological specimens containing radionuclides.  相似文献   

18.
The structural and functional analysis of biological macromolecules has reached a level of resolution that allows mechanistic interpretations of molecular action, giving rise to the view of enzymes as molecular machines. This machine analogy is not merely metaphorical, as bio-analogous molecular machines actually are being used as motors in the fields of nanotechnology and robotics. As the borderline between molecular cell biology and technology blurs, developments in the engineering and material sciences become increasingly instructive sources of models and concepts for biologists. In this review, we provide a--necessarily selective--summary of recent progress in the usage of biological and biomimetic materials as actuators in artificial environments, focussing on motors built from DNA, classical cellular motor systems (tubulin/kinesin, actin/myosin), the rotary motor F1F0-ATPase and protein-based 'smart' materials.  相似文献   

19.
Summary An apparatus is described for the measurement of transmission and reflection of visible light through biological materials. The accuracy of the apparatus is independent of any fluctuations of intensity in the light source.  相似文献   

20.
Summary A modified technique for the estimation of insulin-like activity of serum, using the glucose-uptake of isolated rat epididymal fat tissue is described. The method seems to be reliable, accurate, relatively specific and — in our hands — superior to the diaphragm method.  相似文献   

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