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J Maniloff

Publications and source records attributed to J Maniloff.

At least 73 records · Page 4Linked to original sources
PubMed1977

Host cell and ultraviolet reactivation of ultraviolet-irradiated Mycoplasmaviruses.

The mycoplasma Acholeplasma laidlawii was shown to have mechanisms for both host cell and ultraviolet (UV) reactivation of UV-irradiated mycoplasmaviruses. Host cell reactivation was examined by comparing the survival abilities of UV-irradiated double-stranded deoxyribonucleic acid mycoplasmavirus plated on both untreated and on acriflavine-treated cells. Acriflavine treatment inhibited cell exision repair. Decreased survival on the acriflavine-treated cells demonstrated host cell reactivation. UV reactivation was studied by comparing the survival of UV-irradiated virus plated on untreated cells with its survival on cells that received a small UV dose before plating. The UV-irradiated cells gave increased virus survival, showing UV reactivation. Similar experiments with a single-stranded deoxyribonucleic acid mycoplasmavirus showed that this virus could be UV reactivated, but not host cell reactivated.

Acholeplasma laidlawii↗
PubMed1977

Growth of an enveloped mycoplasmavirus and establishment of a carrier state.

The growth of an enveloped DNA-containing mycoplasmavirus (MVL2 obtained from R.N. Gourlay) has studied, by using the indicator host Acholeplasma laidlawii strain JA1. From virus one-step growth curves, artificial lysis experiments, and infected cell growth curves, it was found that virus infection is nonlytic. Newly infected cells grow slower and are osmotically more stable than uninfected cells. However, 4 to 6 h after infection, the cells reach a carrier state in which cell growth rate and osmotic fragility are indistinguishable from uninfected cells. Carrier cultures contain free virus. Every carrier culture cell gives rise to either a clone of carrier cells or a clone of MVL2-resistant cells.

Acholeplasma laidlawii↗
PubMed1976

Replication of mycoplasmavirus MVL51: attachment of MVL51 parental DNA to host cell membrane.

The replication of the single-stranded circular DNA of MVL51 mycoplasmavirus has been studied with respect to the roles of free and membrane-associated viral DNA intermediates. Replication involves the formation of parental replicative intermediate (RF) molecules on, at most, two to three membrane sites per cell, symmetric RF replication at the membrane and apparent asymmetric RF replication in the cytoplasm leading to single-stranded progeny chromosomes.

Acholeplasma laidlawii↗
PubMed1976

Characterization of an Acholeplasma laidlawii variant with a REP- phenotype.

An Acholeplasma laidlawii variant has been isolated that has a REP- phenotype. The properties of this variant, relative to parental cells, are: (i) it exhibits no change in cell growth kinetics; (ii) it does not propagate single-stranded deoxyribonucleic acid (DNA) mycoplasmaviruses but does propagate double-stranded DNA mycoplasmaviruses; (iii) it converts parental circular single-stranded mycoplasmavirus DNA to double-stranded replicative forms that are not replicated further; (iv) it exhibits no change in host modification and restriction; and (v) it has an increased ultraviolet light sensitivity. The REP- isolate is the first stable mycoplasma variant to which a physiological defect has been attributed.

Acholeplasma laidlawii↗
PubMed1976

Replication of mycoplasmavirus MVL51. IV. Inhibition of viral synthesis by rifampin.

The effect of rifampin on the replication of MVL51, a bullet-shaped mycoplasmavirus with single-stranded circular DNA of molecular weight 2 X 10(6), has been examined in a rifampin-resistant host cell. Rifampin does not block the early steps in MVL51 infection but does decrease the total amount of parental viral DNA taken up. The single-stranded parental viral DNA that enters the cell is found in membrane-associated, double-stranded DNA replicative forms I and II. Rifampin had no significant effect on the synthesis of progeny viral DNA RFI and RFII early in infection and SSI (single-stranded progeny viral chromosomes) later in infection. The rifampin block in virus synthesis was found to be in the step converting SSI into assembled virions. Rifampin was shown to affect the synthesis of virus-specific RNA, Which suggests that viral transcription is necessary for virion assembly.

Acholeplasma laidlawii↗
PubMed1976

Replication of mycoplasmavirus MVL51. III. Identification of a progeny viral DNA-protein intermediate.

Intracellular replication of the non-lytic single stranded circular DNA mycoplasmavirus MVL51 has been shown to involve three DNA intermediates: RFI, RFII and SSI. Growth in Eagle's basal medium, rather than richer tryptose medium, has allowed the identification of an intermediate between nascent progeny chromosomes (SSI) and mature virus. This intermediate is a protein associated form of SSI.

Acholeplasma laidlawii↗
PubMed1974

Partial purification of a membrane-associated deoxyribonucleic acid complex from Mycoplasma gallisepticum.

A Mycoplasma gallisepticum subcellular fraction (P2), which contains the deoxyribonucleic acid replication complex, can be isolated by differential centrifugation of freeze-thaw-lysed cells. The nascent deoxyribonucleic acid is released from P2 by Lubrol-WX, sodium dodecyl sulfate, Pronase, and deoxyribonuclease, but not by saponin, ribonuclease, phospholipase C, or high-frequency sonic treatment. Sonic treatment further fractionates the cell ghost and allows partial purification, on sucrose density gradients, of a deoxyribonucleic acid replication complex attached to the cells' polar membrane-bleb-infrableb structures.

Carbon Radioisotopes↗
PubMed1974

Intracellular replication of mycoplasmavirus MVL51.

The intracellular replication of MVL51, a group L1 mycoplasmavirus, was investigated. The single-stranded parental DNA was found to enter the cell and become converted to double-stranded DNA. This replicated to yield additional double-stranded DNA molecules. The parental viral DNA was found to leave the replication complex and become associated with large molecular weight DNA not involved with viral replication. Progeny viral DNA formed from the double-stranded DNA and an intracellular accumulation of virus chromosome size DNA was observed. The interpretation of this data and a suggested model for the viral replication are discussed and compared to viral DNA replication models for other single-stranded DNA viruses.

Acholeplasma laidlawii↗
PubMed1973

Deoxyribonucleic acid synthesis in synchronously growing Mycoplasma gallisepticum.

Early log-phase cells of Mycoplasma gallisepticum A5969 were synchronized by holding in Eagle minimal essential medium (MEM) for 2 h. When transferred out of MEM into tryptose medium, the cells exhibited synchronous growth. Deoxyribonucleic acid (DNA) synthesis proceeded continuously during this growth but stopped during the period of cell division. One round of DNA replication was observed per cell doubling, and a unique region of DNA was found to be permanently bound to the membrane.

Cell Division↗
PubMed1972

Transfection mediated by Mycoplasmatales viral DNA.

DNA isolated from Mycoplasmatales viruses MVL51 and MVGs51 was infectious when mixed with Acholeplasma laidlawii BN1-Na1(R) cells. Infectivity was destroyed by deoxyribonuclease but not by ribonuclease, Pronase, or specific antiserum to the virus. Host mycoplasma cells were only competent for transfection during late-log growth phase. The rates of the establishment of DNase insensitivity of viral DNA transfectants were similar to those of bacteriophage systems. The dose-response curve for transfection suggested that an average of six molecules of DNA must interact with a cell in order to produce one infectious center. Mycoplasmatales virus DNA exhibited a low efficiency of infection; one infectious center required 4 x 10(5) virus equivalents of DNA.

Bacteriophages↗