Defective Dna Animal Viruses

Rapp, Fred

doi:10.1146/annurev.mi.23.100169.001453

Cited by 20 publications

(10 citation statements)

References 65 publications

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“…This second particle was named PARA (Rapp et al, 1965). This PARA-adenovirus 7 population has been extensively characterized (for reviews, see Rapp, 1969).…”

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confidence: 99%

Properties of transformed hamster cells containing sv40 tumor antigen in the cytoplasm

Richardson

Butel

1971

Intl Journal of Cancer

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“…This second particle was named PARA (Rapp et al, 1965). This PARA-adenovirus 7 population has been extensively characterized (for reviews, see Rapp, 1969).…”

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confidence: 99%

Properties of transformed hamster cells containing sv40 tumor antigen in the cytoplasm

Richardson

Butel

1971

Intl Journal of Cancer

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“…This allows examination of the events that have preceded the interruption and determination of what is required to continue the process of viral replication. Defective virus-cell systems also permit the study of virus-virus interactions, including complementation, enhancement, and interference (34).…”

Section: Discussionmentioning

confidence: 99%

Mixed infections of Coxiella burnetii in restrictive host cells: an immunofluorescent study

Kordová¹,

Kovacóvá²,

Wilt³

1970

Can. J. Microbiol.

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The animal-maintained "phase I" (Ph I) and the egg-grown "phase II" (Ph II) strain of Coxiella burnetii (Cb) were each made up of a natural mixture of particles with different densities (23). When examined by immunofluorescence (IF), their populations behaved as if they were monophasic, both before and after separation by cesium chloride. The Ph I strain, made up of particles of both densities, showed Ph I reactivity and particles of the Ph II strain showed Ph II reactivity. When L-cells (which represent a restrictive host-system for Ph I Cb) were inoculated with large doses of either the Ph I strain of Cb or with particles of a relative density of 1.32 (Ph I), only a few L-cells contained Cb which stained with biphasic serum. The Ph II strain of Cb and particles with a density of 1.27 (Ph II) multiplied well in L-cells and stained readily with Ph II antiserum. Particles which stained with biphasic serum, however, were seen in a few L-cells which had a multiple infection with Ph II Cb. A large inoculum of artificial mixtures of Ph I and Ph II strains of Cb produced many particles in L-cells which stained predominantly with biphasic serum. Interference of growth of Cb occurred using a small inoculum of the mixtures of Ph I and Ph II.Mixtures of active particles of Ph I Cb (host-dependent) and of heat-inactivated Ph II Cb, produced enhancement of growth of Cb. The reactivated Cb were stained predominantly with Ph II antiserum. The possibility that phenotypic mixing of Cb is related to its mode of replication is discussed.

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“…Fetal calf serum gave the same results as calf serum. When Eagle's medium with 10% calf serum was preincubated for 24 Treatment with POL of the cell lines listed in Table 1, at conditions similar to those described for the 3T3 SV40 cells, showed that aggregation occurred within about 24 hr, only with the cells transformed by SV40 or adenovirus 12. The adenovirus 12-transformed cell lines were tested for the presence of SV40-specific nuclear tumor (T) antigen, and found negative.…”

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confidence: 91%

“…Aggregates were observed 24 hr after the addition of POL to SV40-transformed cell clones; however, if the clones were multilayered, they showed aggregation only at the monolayer edges. When 3T3 SV40 cell clones were treated with 20 ,ug/ml POL 6 days after seeding, about 98% of the clones showed aggregation.…”

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confidence: 97%

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Specific Aggregation of SV40-Transformed Cells by Ornithine, Leucine Copolymers

Duksin

Katchalski

Sachs

1970

Proc. Natl. Acad. Sci. U.S.A.

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Abstract. A basic copolymer of ornithine and leucine (1:1) was shown to rapidly agglutinate, in the absence of serum, normal cells and cells transformed by viral and nonviral carcinogens. This agglutination was inhibited by addition of serum. In presence of serum, the same copolymer and those of ornithine and valine (1:1) and arginine and leucine (1: 1), produced a specific aggregation of simian virus 40 (SV40)-transformed cells cultured for about 24 hr after addition of the peptide. The rapid agglutination and SV40-specific aggregation could not be inhibited by a variety of individual amino acids or carbohydrates. The specific aggregation could be detected in mixtures of SV40-transformed and other cells, and it was not prevented by x-irradiating the cells with 4000 R. Aggregation of the SV40-transformed cells was inhibited by acidic polyamino acids provided these were added not later than about 5 hr after addition of the basic copolymer. The results indicate that the basic copolymer, in the presence of serum, produces a change in SV40-transformed cells, presumably in the surface membrane, that causes the cells to aggregate. In addition to the aggregation of cells transformed by SV40, cells transformed by adenovirus 12, which did not contain detectable SV40-specific nuclear tumor (T) antigen, were also aggregated by the basic copolymer in the presence of serum. This indicates that the ornithine,leucine copolymer is able to detect an SV40-like change in the surface membrane of cells transformed by adenovirus 12.The change in cellular regulatory mechanism that is produced by the transformation of normal cells by carcinogenic agents can be ascribed to a change in the cell-surface membrane.1 The use of chemicals with specific binding sites should be of value in elucidating the nature of this structural change. Results obtained with the carbohydrate-binding protein concanavalin A have indicated that binding sites for this protein exposed on the surface of transformed cells are in a cryptic form on normal cells.2 The exposure of other carbohydrate-containing sites on the surface membrane of transformed cells has also been suggested from agglutination experiments with a wheat germ glycoprotein3 and a soybean glycoprotein.4 The results of these studies have shown changes that were common to cells transformed by various types of carcinogens. The present studies with synthetic polyamino acids were undertaken to determine whether these compounds may be useful in further elucidating the difference between normal and transformed cells, and whether they could be used to detect membrane changes that may be specific to cells transformed by different carcinogenic agents.

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Defective Dna Animal Viruses

Cited by 20 publications

References 65 publications

Properties of transformed hamster cells containing sv40 tumor antigen in the cytoplasm

Properties of transformed hamster cells containing sv40 tumor antigen in the cytoplasm

Mixed infections of Coxiella burnetii in restrictive host cells: an immunofluorescent study

Specific Aggregation of SV40-Transformed Cells by Ornithine, Leucine Copolymers

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