Negative staining of viruses

Nermut, M. V.

doi:10.1111/j.1365-2818.1972.tb01064.x

Cited by 31 publications

(12 citation statements)

References 18 publications

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“…Freeze-drying of negatively stained specimens combines high resolution of negative staining with prevention of drying artifacts (7).…”

Section: Negative Staining Followed By Freeze-dryingmentioning

confidence: 99%

Size, shape and surface structure of mouse mammary tumour virus (MTV)

Nermut

1973

Archiv f Virusforschung

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Freeze-drying and freeze-etching techniques prevent drying artifacts and changes brought about by fixation and thus provide better information about the size, shape and native structure of viruses. The electron microscope appearance of MTV was described by a number of authors both after conventional negative staining and in ultrathin sections (1--6, 11, 13, 14, 16). Encouraged by the experience obtained with murine leukaemia viruses (9) we have studied the MTV with the freeze-drying technique. The main purpose of this study was to establish the true shape, size and surface structure of MTV using the freeze-drying technique and to compare the obtained results with those obtained by conventional techniques.Mouse mammary tumour virus was prepared from spontaneous and transplanted mammary tumours arising in C3H/Avy and Balb/cfC3H mice by the method of CALAFAT and HAG]S~rA~ (2). The purified virus was suspended in 0.01 M Tris/ HC1 pH 7.2--0.14 M NaC1 buffer containing 0.04 per cent bovine serum albumin.Samples for electron microscopy were prepared using the following techniques : a) conventional negative staining with either 2 per cent phosphotungstate (PTA) pH 6.0 or pH 7.2 ; ammonium molybdate (AM) pH 6.5 or 1 per cent uranyl acetate (UA) pH 4.4, b) negative staining with PTA, AM or UA fo]lowed by freeze-drying (7), c) freeze-drying with unidirectional shadowing with platinum-carbon using Balzers freeze-etch unit BAF 300 (9), d) fixation with either 0.1 per cent or 1.0 per cent osmium tetroxide for 10 minutes or longer, or with 3 per cent or 5 per cent glutaraldehyde for 10 minutes followed by negative staining with AM, PTA, or UA. (Fixation was done after the virus was adsorbed on the electron microscope grids.) Specimens were observed with a Philips EM 300 electron microscope at 6O kV. Conventional Negative Staininga) Unfixed virus particles were fairly pleomorphic when stained negatively with PTA or AM. About one third of them were 'tailed' particles, others were either

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“…Freeze-drying of negatively stained specimens combines high resolution of negative staining with prevention of drying artifacts (7).…”

Section: Negative Staining Followed By Freeze-dryingmentioning

confidence: 99%

Size, shape and surface structure of mouse mammary tumour virus (MTV)

Nermut

1973

Archiv f Virusforschung

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“…Each of these stains provides a different pattern of electron density; PTA penetrates membranes, whereas UA coats surface structures without penetration [11][12][13]. Sample fractions (50 Al) were placed on carbon/formvar-coated 200-mesh copper or nickel grids.…”

Section: Em Negative Stainingmentioning

confidence: 99%

Ultrastructural Characterization of Endogenous Retroviral Particles Isolated from Normal Human Placentas1

Lyden¹,

Johnson²,

Mwenda³

et al. 1994

Biology of Reproduction

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Human placental endogenous retroviral (ERV) particle isolates were investigated by ultrastructural evaluation. Although retrovirus-like structures in normal human placental tissue sections have been described, the precise nature of these particles has not previously been defined. By direct electron microscopic (EM) observation of placental ERV isolates that display retroviral reverse transcriptase (RTase) activity and a buoyant density consistent with type-C retroviruses (1.17 g/ml on sucrose), we have shown these to contain particles with characteristic retroviral ultrastructural features. Samples were stained with 1.0% phosphotungstic acid (PTA), 0.5% uranyl acetate (UA), and low-angle-shadowed with platinum/palladium. Isolated placental ERV particles have an apparent diameter of approximately 120 nm, are membrane-bound with a short surface fringe, and contain capsid particles (about 90 nm in diameter) within an internal matrix structure. These observations support the view that human placental cells normally express ERV particles.

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“…Ainsi, chez un virus de leuctmie murine, il prtvient la formation de "queues" et permet de visualiser les spicules ptriphtriques (27). Un autre sel d'uranyle, le formiate, permet de visualiser la structure htlicoi'dale du virus de la mosai'que du tabac (25).…”

Section: Efet De I'acctate Sur Les Ditnensions Des Phagesunclassified

“…tures difficiles a voir avec des sels de phosphotungstate (10,25,27). Cependant, l'effet de l'acktate d'uranyle sur les dimensions des virus n'a fait l'objet d'aucune etude statistique approfondie.…”

Section: Introductionunclassified

Avantages et inconvénients de l'acétate d'uranyle en virologie comparée: étude de quatre bactériophages caudés

Ackermann¹,

Jolicœur²,

Berthiaume³

1974

Can. J. Microbiol.

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Effects of uranyl acetate (UA) and potassium phosphotungstate (KPT) on dimensions of four tailed bacteriophages have been studied comparatively. All UA stained preparations show positive (UA+) or negative (UA−) staining according to the local, low- or high-particle concentration, and crystals containing swollen, distorted phages. UA causes flattening or shrinking of phage heads, the latter especially after positive staining. Transverse diameters of elongated heads are reduced, and capsids, tails, and tail fibers may be swollen. In addition, isometric heads may show pentagonal outlines and tails may be elongated. Dimensions of phages TP50 and PBP1 have been analyzed by the method of multiple discriminant analysis. Differences between KPT, UA−, and UA+ stained viruses are statistically highly significant (P < 0.001). Dimensions of UA+ stained viruses appear to be unreliable for taxonomic purposes. Dimensions of UA− stained viruses are to be controlled by other staining methods. UA has several advantages but phosphotungstate stains should be preferred, particularly in staining large cubic DNA viruses.

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Negative staining of viruses

Cited by 31 publications

References 18 publications

Size, shape and surface structure of mouse mammary tumour virus (MTV)

Size, shape and surface structure of mouse mammary tumour virus (MTV)

Ultrastructural Characterization of Endogenous Retroviral Particles Isolated from Normal Human Placentas1

Avantages et inconvénients de l'acétate d'uranyle en virologie comparée: étude de quatre bactériophages caudés

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