摘要:

SummaryThe aim of this paper is to provide a strategy for measuring intracellular antigens combined with DNA content in cells or nuclei. A series of protocols are included which enable the majority of such antigens to be labelled and further information is provided for cases in which the standard methods prove to be inadequate. The basic principles of cell permeabilization/fixation are described, thus explaining how methods can be divided into three basic categories: (a) alcohol fixation with or without detergent pretreatment; (b) paraformaldehyde fixation followed by permeabilization with alcohol or detergents; (c) permeabilization of unfixed cells. The preparation of nuclear suspensions from paraffinembedded material is described and the possibilities and problems of staining such suspensions for nuclear antigens are discussed. Examples of results obtained with the detailed protocols are given for staining with antibodies directed against proliferating cell nuclear antigen (PCNA), Ki‐67 antigen and Ki‐Sl antigen. Details of published studies of a variety of intracellular antigens are given in two tables. The power of multiparametric flow cytometry in the study of cell proliferation, differentiation and response of cells to damage is underli

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1994.tb03493.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

SummaryBacterial antibiotic susceptibility was rapidly estimated forEscherichia coliandStaphylococcusspp. by flow cytometry. This was achieved by measuring the uptake of a negatively charged membrane potential sensitive dye bis‐(1,3‐dibutylbarbituric acid) trimethine oxonol and observing changes in low‐angle light scatter (excitation light scattered by up to 15°). Estimations of ampicillin, gentamicin and ciprofloxacin susceptibilities were possible within 2–5 h from a plate culture, depending on the species and antibiotic used. This includes the time necessary to establish steady‐state growth in liqu

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1994.tb03494.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

SummaryMulti‐parameter flow cytometry was investigated for the rapid detection of specific serotypes of salmonellas (S. typhimuriumandS. montevideo) labelled with fluorescent monoclonal antibodies, both in pure culture and in a typical food matrix (full‐fat milk). In all cases, the method was accurate to levels of below 104target cells per ml for a total assay time of about 30 min. After 6 h non‐selective enrichment in the presence of a 10 000‐fold excess of competing micro‐organisms (Escherichia coli) the corresponding detection limit was about 20 cells ml−1. These results suggest that flow cytometry has significant potential for the detection of pathogenic micro‐organisms in the

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1994.tb03495.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

SummaryThe fluorescence photobleaching method has been widely used to study molecular transport in single living cells and other microsystems while confocal microscopy has opened new avenues to high‐resolution, three‐dimensional imaging. A new technique, scanning microphotolysis (Scamp), combines the potential of photobleaching, beam scanning and confocal imaging. A confocal scanning laser microscope was equipped with a sufficiently powerful laser and a novel device, the ‘Scamper’. This consisted essentially of a filter changer, an acousto‐optical modulator (AOM) and a computer. The computer was programmed to activate the AOM during scanning according to a freely defined image mask. As a result almost any desired pattern could be bleached (‘written’) into fluorescent samples at high definition and then imaged (‘read’) at non‐bleaching conditions, employing full confocal resolution. Furthermore, molecular transport could be followed by imaging the dissipation of bleach patterns. Experiments with living cells concerning dynamic processes in cytoskeletal filaments and the lateral mobility of membrane lipids suggest a wide range of potential biological applications. Thus, Scamp offers new possibilities for the optical manipulation and analysis of both technical and biol

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1994.tb03496.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

SummaryThe U.S. Department of Energy and the U.S. Bureau of Mines conducted experiments to determine the feasibility of reducing the pyritic sulphur content of a conventionally cleaned Pittsburgh seam coal by heap leaching. Two identical heaps, one indoor and one outdoor, were constructed, and sprayed with recycled rainwater/leachate for approximately 200 days. Lump samples were selected prior to initiation of heap leaching activities and from both heaps after 5‐ and 11‐month intervals for microscopic (petrographic) examination. These examinations revealed no significant differences in the occurrence of pyrite oxidation between the two heaps. These observations were consistent with the results from the chemical analyses that showed no significant differences in pyritic sulphur removal between the indoor and outdoor heaps. Samples from the starting coal were also selected and examined to see how different pyrite morphologies behaved during artificial weathering. Dendritic and framboidal pyrite forms appeared to be the more reactive fo

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1994.tb03497.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

SummaryThe Fresnel contrast in high‐resolution images of the Σ = 3{112} aluminium twin boundary is quantitatively assessed to determine whether the rigid body displacements might be measured. It is demonstrated that the effects of the shears at the boundary preclude this possibility. By comparison, simulations of low‐resolution images of the same boundary show that the Fresnel fringe contrast in this type of image is negligibly affected by the shear displacements as well as being of considerably higher contrast. The reasons why it is thus only the low‐resolution images that can provide high‐resolution data on the displacements are d

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1994.tb03498.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

SummaryThe effect of noise in the fractal characterization by frequency analysis of surface images obtained by scanning tunnelling microscopy (STM), atomic force microscopy (AFM) or profilometry has been studied. The origin of noise and its relationship to the signal is discussed. A procedure to simulate noisy images is presented. From the study it is concluded that the method usually used to characterize noise in STM is not valid and it is shown that fractal characterization of surfaces when noise is present by traditional frequency analysis methods is not possible. A new method to perform both the noise characterization and the fractal characterization of surfaces when noise is present is proposed.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1994.tb03499.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

SummaryX‐ray contact microscopy with a 300‐ps‐duration laser‐plasma X‐ray source has been used to image hydrated human chromosomes. Clearly imaged are individual nucleosomes and their higher‐order particles (superbeads), elementary chromatin fibrilsc. 30 nm in diameter and their higher‐order fibres of various sizes up toc. 120 nm in diameter. The results demonstrate that X‐ray microscopy is now capable of opening a new path of investigation into the detailed structures of hydrated chromosome fibres in thei

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1994.tb03500.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

SummaryA major practical advantage of the HOME (highly optimized microscope environment) computerized microscope is the facility for relocating cells or other microscopic objects. Features can be marked directly on the microscope image using a mouse‐driven cursor, and an interactive finder can then be used to relocate the marked features. Tests on a prototype HOME microscope have shown that positions can be relocated with an accuracy of standard deviation (SD)<7 μm. The marked features could also be relocated on a second HOME microscope, although with somewhat reduced accuracy (standard deviations of<17 μm). The system provides a very user‐friendly environment for tasks requiring relocation of microscopic ob

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1994.tb03501.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Book reviewed in this article:Practical Electron Microscopy. A Beginner's Illustrated Guide. (2nd Edition). By ElaineHunterElectron Beam Analysis of Materials. By M. H. LorettoFractals in Biology and Medicine. By T. F. Nonnenmacher, G. A. Losa.&E. R. Weibel(editors).

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1994.tb03502.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY