摘要:

SYNOPSISThough azo dyes are not fluorescent in solutions, many azo dyes become fluorescent when bound to tissues. This fluorescence is determined largely by the aromatic components of the dye molecules. Like chromophores, these fluorophores are affected by other groupings in dye molecules. Relatively short, compact systems of conjugated double bonds or linking of such resonators by insulating groups favours fluorescence. Long chains of conjugated double bonds and coupling of azo groups in the 1,4‐ or 2,7‐ position of naphthols diminish or abolish fluorescence. Various factors considered important for the fluorescence of other classes of dyes, such as ring closure, coplanarity of chromophores, accumulation of ring systems and low dye concentration are detrimental to the fluorescence of azo dyes. However, these rules apply only to azo dyes; the fluorescence of triphenylmethane, anthraquinone, and quinone‐imine dyes is governed by different factors. Three dioxazine dyes and three copper phthalocyanine dyes included in this study were non‐fluo

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1967.tb04513.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SYNOPSISGelatinous fibres ofSalix fragilisL. are characterized by an inner layer of cellulose which is relatively unlignified when compared with normal wood fibres. The gelatinous layers of mature gelatinous fibres sometimes show a reaction with benzidine or with ruthenium red. Fibres may sometimes have a terminal lamella which borders the lumen. It is suggested that the irregular distribution of organelles within differentiating fusiform cells is responsible for the spasmodic histochemical reactions and presence of a terminal lamella.The Coppick and Fowler method may be used for the localization of lignin in ultra‐thin sections.Although starch grains have often been seen within fibres, their presence has not been clearly related to the presence of gelatinous fibres alone.From light, polarizing and electron microscopical evidence, the walls of normal wood fibres have been found to be composed of S1+ S2+ S3layers or of S1+ S2layers only. The gelatinous fibres invariably have a gelatinous layer which may replace either the S3or both the S3+ S2layers.Microfibrillar disorientations of the gelatinous layer as seen in carbon replicas appear to be caused by the presence of simple pits or incipient slip planes. It appears that the pits through the gelatinous layer may become distended during processing for light microscopy.The convoluted appearance of the gelatinous layer in some sections is now considered to be an artifact brought about by processing and sectioning of fibres.No evidence has been found that the gelatinous layer is formed other than by the gradual deposition of wall material, whether or not there may be periods of faster or slower wall synthesi

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1967.tb04514.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SYNOPSISThe stages leading to the depositing of individual molecules of Polyacrylamide by spray technique have been studied electron microscopically. The number and weight average molecular weights of a high‐molecular‐weight fraction of Polyacrylamide were found to be 2.33 ± 0.23 × 106and 2.59 ± 0.26 × 106respectively, while the intrinsic viscosity determination gave 2.71 × 106. The molecular weight distribution for the fraction was also de

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1967.tb04515.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SYNOPSISAlthough the saccharide side chains of epithelial mucinsin situ(presumably glycoproteins) can be readily stained, it is difficult to demonstrate the protein core of such mucins histochemically, even following attempts to remove the saccharide residues by various chemical and enzymatic treatments. A protein presumed to be extrinsic to the mucin may be demonstrated directly, under certain circumstances, by the acid dye Biebrich scarlet and indirectly by the increase in basophilia following brief proteolysis. Thiol and disulphide groups in mucins may be demonstrated by both direct and indirect techniques.

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1967.tb04516.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SYNOPSISThe dinitrofluorobenzene reaction without subsequent chemical treatment has been shown to be suitable for combination with the Feulgen procedure to provide a means of measuring protein and DNA in the same cell. The density of dinitrofluorobenzene colouration per cell is affected by the fixation procedure and by the composition and temperature of the DNFB solution but with all the treatments used, the same reproducible maximum optical density per cell was obtained by increasing the temperature at which the reaction was carried out. The Feulgen procedure has no effect on the optical density of cells previously treated with dinitrofluorobenzene and is not affected itself by this previous staining procedure.

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1967.tb04517.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SYNOPSISUltramicrotomy of narrow specimen layers (<15 μ) requires special attention to the mechanics of block alignment. A systematic approach to levelling of the block face can increase the percentage of full face (“isometric”) sections and minimize specimen loss. The method proposed has been derived from geometric equations and provides a rational basis for the instruction of technical personnel. The significance of an initial angular displacement with respect to the ideal cutting plane is gauged from the percentage of block face obtained with the first ultratome stroke, and the maximum thickness of the first section. The latter is determined from reflection colours. The magnitude of angular displacement may be directly calculated or estimated graphically. Present means of microtome chuck or knife stage control permit approximate mechanical correction of alignment errors, but chief reliance must remain upon technical expertise. Experiments indicate that visual training can result in a relatively consistent alignment of the block face in the horizontal (knife edge) plane (<0.2° error), but that preliminary vertical alignment is usually less accurate. For a given percentage of isometric sections, the tolerable degree of alignment error is inversely proportional to the length of the block

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1967.tb04518.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SYNOPSISAt present, the chemical structures of macromolecules actually in tissues cannot be determined, mainly because histochemical techniques are rarely specific for a particular chemical group. This field might prosper if it were possible to make use of the unique ability of aldehydes to be converted into highly‐coloured formazans. This is achievedin vitroby condensing aldehydes with an arylhydrazine and coupling the hydrazone thus formed with a diazotized aromatic amine at a pH around 9. However,in situthis may be more complicated. For example, when periodate‐oxidized mucosubstances (containing engendered aldehydes) are converted into formazans by a similar sequence, coloured tetrazenes and azo‐derivatives, among other products, may be formed as well. Some of the many factors which can affect the conversion of periodate‐oxidized mucosubstances into formazans are reviewed in this paper. They include the nature of the “aldehydes” engendered in mucosubstances by periodic acid; the stabilities of periodate‐oxidized mucosubstance arylhydrazones; the course of the coupling reaction between diazon‐ium salts and mucosubstance arylhydrazones; and the presence of groups other than ofc‐glycols in the mucosubstance macromolecule (e.g. su

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1967.tb04519.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SYNOPSISPeriodate‐reactive mucosubstances have been converted into highly‐coloured formazans (as predicted in a previous paper; Stoward, 1967b) by treating periodate‐oxidized sections of fixed tissue first with Phenylhydrazine hydrochloride in phosphate buffer (pH 4–6) and then with tetrazotized 3,3′‐dimethoxybenzidene fluoro‐borate (TDMBF) in aqueous pyridine. The colours of such mucosubstance formazans varied from red through brown and yellow to purple. When diazotized aniline fluoroborate was substituted for TDMBF, the mucosubstance formazans thus obtained were yellow and difficult to distinguish from the surrounding connective tissue.The uptake of excess TDMBF by carboxyl groups of connective‐tissue proteins was prevented by methylating tissue sections beforehand with methanolic thionyl chloride. Most mucosubstance formazans synthesized in such tissues usually contrasted better with the surrounding connective tissue than in unmethylated sections, but their intensity of colour was reduced. In such methylated sections glycogen did not form a formazan and a few mucosubstance “formazans” were colourless. Some mucosubstance formazans in methylated sections coupled substantially with l‐amino‐8‐naphthol‐4‐sulphonic acid, but others did not appear to do so. The wide range of colours and properties exhibited by mucosubstance formazansin situare probably related to the structure of the periodate‐oxidized “dialdehyde” saccharide units of the mucosubstance from which the formazans were derived. In some periodate‐oxidized mucosubstances such as those in hamster colonic mucous cells, the “dialdehydes” were probably hydrated and underwent internal condensation to form derivatives which, although they reacted with Schiff's reagent, could not be converted into formazans.The several experimental factors which affected the yield and colour of mucosubstance for

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1967.tb04520.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SYNOPSISIn sections of fixed tissue, periodate‐oxidized mucosubstances that have been treated firstly with Phenylhydrazine and secondly at a pH near 9 with a diazonium salt, such as diazotized aniline or tetrazotized 3,3′‐dimethoxybenzidine, are converted into highly‐coloured derivatives which could be formazans, azo‐compounds, tetrazenes, or a mixture of these. That such derivatives are in fact mostly, if not exclusively, formazans has been confirmed by treating these derivativesin situfirstly with N‐bromosuccinimide, to oxidize acid‐labile formazans into acid‐stable, colourless tetrazolium salts; secondly, with a hot ethanolic solution of hydrochloric acid, to destroy azo‐derivatives and tetrazenes and leave tetrazolium salts untouched; and thirdly, with an aqueous solution of ammonium sulphide, to reduce the mucosubstance tetrazolium salts back to the original c

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1967.tb04521.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SYNOPSISA survey of ultrastructure in the relatively largeShepheardella tceniformis(Foraminifera) reveals several features not observed previously in this group of protozoans. Microtubules, 210–250 A in diameter, occurring in the pseudopodia and also in the cytoplasm, where they form a 1–2 μ peripheral layer, are illustrated and their possible function discussed. The huge interphasic nucleus has an envelope, roughly comparable but more complex than that found inAmoeba, which reverts to a conventional nuclear membrane during division. In the cytoplasm there are numerous 0.5 μ microbodies, of unknown function, superficially resembling vertebrate hepatic uricosomes, and which, so far as is known, are unique in protozoan ultra‐st

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1967.tb04522.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY