摘要:

SYNOPSISThe periodic acid‐Schiff (PAS) technique of Hotchkiss (1948) has been used to follow the action of tumour‐inhibitory, native gum tragacanth on cells of the Landschütz mouse ascites tumourin vivo. The results have been compared with those of various non‐inhibitory modified tragacanth samples and of gum karaya (kutira grade), and have been related to earlier studies of changes in mitosis and in cell permeability after treatment of the tumour with the same gums. PAS‐stained particles are observed surrounding the tumour cells and attached to their surfaces as early as 10 minutes after treatment with inhibitory gum and no similarly stained material, additional to that in control cells, is detected within the treated cells until 5 to 6 hours after commencement of treatment.Non‐inhibitory gum samples formed PAS‐stained particles of different size and shape which were not bound to the surface of the tumour cell. No additional PAS‐stained material appeared within the cells after treatment with these samples.It is concluded that the active gum causes growth inhibition by direct action at the surface of t

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1965.tb02127.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SYNOPSISThe uptake of RNase by two types of amoeba and a selection of vertebrate cells has been investigated using the fluorescein‐labelled enzyme. This method is considered satisfactory for the study since the fluorescein label migrated together with the enzyme during electrophoresis, and the labelled RNase retained one half of its enzymatic activity. Although RNase was ingested as droplets by bothAmoeba proteusandAcanthamoebasp., these two amoebae differed in their extent of surface adsorption of the enzyme and in the effect of RNase on the activity of their contractile vacuoles. Cytoplasmic droplets were also ingestedin vitroby a small proportion of ascites cells, but there was no detectable uptake by rabbit kidney, mouse fibroblast, chick embryo or HeLa culture

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1965.tb02128.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SYNOPSISThe electron microscope can reveal details of both the infective process and the morphology of bacteriophages. Various standard specimen‐preparation methods are available for these studies: negative staining is the most valuable method for morphological aspects and the sectioning of bacteria for studying intracellular multiplication. Phages fall into six distinct morphological groups. Detailed examination of these reveals a variety of forms showing variations within each group. All phages have one thing in common, the possession of symmetry; the heads have recognisable geometrical shapes and the tails, when present, possess morphological subunits usually clearly arranged in a regular fashion.Phage morphology is important not only as a fundamental characteristic, but also as a major criterion for taxonomic purposes. However, some phages, which are morphologically similar, can infect bacterial hosts in different genera or families so that additional criteria such as host range have to be used in considering a possible system for the classification of bacteriophages.The electron microscope is particularly suitable for providing information about the adsorption and intracellular multiplication stages of the infective process. Shadowing and negative staining show that tailed phages adsorb tail first, and that tail‐less ribonucleic acid phages attach to bacterial fimbriae in large numbers. Sections of infected bacteria reveal cytological changes within the cell during intracellular multiplication.In addition, the electron microscope can be used to investigate the natural habitats of phages. In one of these a particle with an unusual “life cycle” was found associated with the genusBacillus. It normally exists in the prophage state in a lysogenic host. It is active on indicator strains, but only kills them and cannot multiply within them.These various aspects are reviewed in detail with particular reference to information provided by the electron mic

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1965.tb02129.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SYNOPSISHuman foetal skin can develop in tissue culture using a synthetic chemically defined medium. The development produces squamous type epithelium which subsequently forms keratin. The assumption of squamous morphology is associated with the appearance of a reaction for acid phosphatase, non‐specific esterase and cysteine desulphurase. These enzymes show a distinct intensification in the zone between the squamous and keratin layers. The findings suggest that the process in this system closely parallels that in viv

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1965.tb02130.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SYNOPSISA method for the identification and localization of catalase in histological sections is described. Sections are placed in contact with a thin film of starch gel which is immersed in hydrogen peroxide and then in a solution of potassium iodide. The starch film turns dark blue except where the hydrogen peroxide in it has been destroyed by catalase. At these points the film remains white.

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1965.tb02131.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SYNOPSISHistochemical methods were used to determine the basis of aldehyde fuchsin staining in the following tissue constituents: the preoptic and neurohypophysial neurosecretory material of the Bullhead (Cottus gobio) and the pancreatic zymogen granules, gastric‐chief‐cell granules, Paneth‐cell granules, elastic tissue, and acidic mucins of intestinal goblet cells in the mouse.Following oxidation, the staining of neurosecretory material, pancreatic, gastric, and Paneth granules, and elastic tissue is probably due to ionic links with the acidic products of cystine oxidation.Staining occurred without oxidation in pancreatic, gastric, and Paneth‐cell granules and elastin; this reaction is probably non‐ionic, but the chemical groups responsible are still undetermined.Acidic mucins probably stain by ionic linkage to sulphate groups. This confirms previous results.The aldehydes which are artificially produced in the Feulgen and ninhydrin‐Schiff techniques are stained with aldehyde fuchsin but

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1965.tb02132.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SYNOPSISThe structure of the cell wall of coconut fibre cells has been investigated by replica and sectioning techniques. The results of this investigation are outlined.

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1965.tb02133.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1965.tb02134.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SYNOPSISThe histochemical demonstration of aminopeptidase activity has been studied in unfixed frozen sections; it has been shown that Fast Blue B permits less diffusion than do two other coupling agents. With this tetrazonium salt the enzyme has been localized predominantly in discrete particles in the liver, intestine, and kidney of the rat. Evidence is offered indicating that these particles may be true cellular organelles, the properties of which may be akin to those of the lysosomes.

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1965.tb02135.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SYNOPSISChanges in dimensions of some spherical and cylindrical particles due to metal shadowing for electron microscopy have been investigated. Monodisperse polystyrene latex, colloidal gold particles, Bushy Stunt and Tobacco Mosaic Virus, normal human adult haemoglobin and DNA molecules were used as experimental material. Particles were deposited on carbon coated platinum grids and shadowed with platinum vapour using a fixed shadowing geometry. With the exception of TMV, haemoglobin and DNA, distortion was measured on individual particles by taking micrographs of the same particles before and after shadowing. Distortions were measured on a large number of particles both parallel and perpendicular to the shadow direction. On the smaller particles, the distortions in the two directions were estimated from the heights, deduced from shadow length, and measurement of the widths parallel and perpendicular to the shadow. The distortions were plotted against particle diameters. The distortion parallel to the shadow was found to be greater than that measured perpendicular to the shadow and both were found to increase up to a particle diameter of about 200 Å and thereafter became practically constant. The use of the calibration curves in the measurement of the dimensions of small biological particles has been discussed using the example of normal human foetal haemoglobin and egg albumin molecules

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1965.tb02136.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY