摘要:

AbstractLactoferrin, a DNA‐binding protein, was complexed to colloidal gold and applied on ultrathin sections of resin‐embedded plant tissues and bacterial cultures. Optimal results were obtained when lactoferrin was tagged to colloidal gold particles at pH 9.2. Postfixation with osmium tetroxide and embedding with Epon did not prevent the accessibility of the protein towards its corresponding binding sites. In plant nuclei, labeling was observed over the dense chromatin and to a lesser extent over the dispersed chromatin. Nucleolar labeling was preferentially located over the dense fibrillar component. Gold particles were also found to be associated with chloroplasts and mitochondria. In prokaryotic cells, a dispersed labeling was noted over the cytoplasm and, in some cases, the aggregation of few gold particles suggested the presence of packed DNA fibrils. Various control experiments confirmed the specificity of the labeling pattern obtained. Lactoferrin‐gold complex appears to be a valuable probe for the intracellular demonstration of DNA molecules in double‐fixed and Epon‐embedde

ISSN:0741-0581    

DOI:10.1002/jemt.1060120102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractAtomic‐level details are easily resolved in the latest generation of intermediate voltage electron microscopes, but structural information on the same scale can only be extracted under certain specific conditions. Some understanding of imaging theory, as well as an awareness of correct operating conditions, is required for reliable image interpretation. Several representative examples are chosen to illustrate the possibilities for atomic‐resolution imaging of materials, and perspectives and outlook for the technique are briefly discus

ISSN:0741-0581    

DOI:10.1002/jemt.1060120103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractA technique for performing light, scanning, and transverse transmission electron microscopy on cultured cells grown within a single tissue culture flask is described. Permanent light microscopy slides are obtained by removing selected portions of the plastic tissue culture vessel and mounting them on glass slides with an aqueous mounting solution. The images obtained from these slides are superior to viewing through the bottom of the flask with an inverted stage microscope. For scanning electron microscopy, selected areas are also cut from the remainder of the vessel and prepared for viewing. The final portion of the culture container is transferred and attached to a new tissue culture vessel and prepared for transmission electron microscopy using alcohol instead of acetone and propylene oxide during dehydration, infiltration, and embedding.

ISSN:0741-0581    

DOI:10.1002/jemt.1060120104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractThe FORTRAN source code is given for a computer program that calculates the two‐dimensional intensity distribution in convergent‐beam transmission electron microdiffraction (CBED) patterns from perfect crystals. The program uses the eigenvalue or Bloch‐ware method. It allows three‐dimensional dynamical diffraction, and so includes all higher‐order Laue zone effects without approximation. No symmetry reduction is included. The program accepts noncentrosymmetric or centrosymmetric crystal structures and allows absorption corrections to be included. It uses the “EISPACK” subroutines for the diagonalisation of a general complex matrix. Up to 100 CBED disks may be included. The code is also available

ISSN:0741-0581    

DOI:10.1002/jemt.1060120105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

ISSN:0741-0581    

DOI:10.1002/jemt.1060120106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

ISSN:0741-0581    

DOI:10.1002/jemt.1060120107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractAs a microscale tool for observing GaAs‐AlxGa1–xAs heterostructures, backscattered electron (BE) images in the scanning electron microscope (SEM) were compared with conventional secondary electron (SE) images. BE images were found to be more sensitive to compositional differences between GaAs and AlxGa1–xAs and less sensitive to surface roughness. BE images have a spatial resolution of 10 nm or better. This method enables the nondestructive observation of ultrafine lateral periodic structures, such as quantum‐well‐wire (QWW) structures, fabricated by compositional disordering technology using focused Ga ion‐beam (Ga‐FIB) implantation into GaAs‐AlxG

ISSN:0741-0581    

DOI:10.1002/jemt.1060120108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractA new method was developed which is suitable for the preparation of mammalian sperm for scanning electron microscopy under either laboratory or field conditions. Samples of ejaculates from humans, two ferret species, and epididymal sperm from the African elephant were diluted in Millonig phosphate buffer and then fixed in glutaraldehyde solution. A small sample of the fixed sperm suspension was diluted in the same buffer, withdrawn with a syringe, and injected very slowly onto either a cellulose acetate or a polycarbonate membrane filter. This step was essential to concentrate the dilute sperm samples. During the various dilution steps most of the granular prostatic secretions were lost. However, a protein‐like sheath, which remained attached to most sperm, obscured the surface features and had to be removed for SEM studies. It was removed by prolonged fixation/etching in 1% osmium tetroxide. Membrane filters containing sperm on their surfaces then were dehydrated, dried by the critical point drying method, and sputter coated with gold. Polycarbonate filters were superior to cellulose acetate filters in producing a flat and homogeneous backgroun

ISSN:0741-0581    

DOI:10.1002/jemt.1060120109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractThe term “etching,” in electron microscopy, refers to the removal of specimen surface layers and includes chemical, electrolytic, and ion‐beam methods. The ion‐beam etching process is used to remove layers of a target material by bombarding it with ionized gas molecules. Recently, the method has been applied to the field of biological specimens; however, the practical procedures for such organic materials have not been developed. In the present study, we used an apparatus in which a beam of argon ions is collimated and focused by electrostatic lenses onto an appropriate target. We demonstrated the optimum conditions to observe biological specimens that were treated with osmium tetroxide and tannic acid. The specimens were examined uncoated at low accelerating voltage using a field emission scanning electron microscope.According to our experiments, when a biological specimen was observed under high‐resolution conditions at over 50,000x magnification, the optimum condition of ion‐beam etching consisted of an accelerating voltage of E = 1 keV and an ion‐beam dose of It = 360 ∼ 400 μA. min, depending on parts of the specimens. In order to decrease overetching, we had to choose factors such as E = 1 ∼ 2 keV an

ISSN:0741-0581    

DOI:10.1002/jemt.1060120110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

ISSN:0741-0581    

DOI:10.1002/jemt.1060120101

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY