PubMed Health⌕ Search

Biomedical subjects

J L MELNICK

Publications and source records attributed to J L MELNICK.

At least 19 recordsLinked to original sources
PubMed1965

DIFFERENTIAL EFFECTS OF INHIBITORS ON THE STEPS LEADING TO THE FORMATION OF SV40 TUMOR AND VIRUS ANTIGENS.

The effect of DNA antagonists and various antibiotics on steps in the synthesis of SV40 virus in green monkey kidney cells was investigated. Both the early forming tumor (T) antigen, as well as the later synthesized virus (V) antigen, were synthesized in the presence of fluorouracil and iododeoxyuridine. Cytosine arabinoside (and fluorodeoxyuridine in starved cells) prevented synthesis of V antigen but not T antigen. The synthesis of T antigen therefore does not require synthesis of virus DNA. Virus particles formed only in the presence of the iododeoxyuridine and they were non-infectious. Actinomycin D inhibited synthesis of both tumor and virus antigens, suggesting that the synthesis of these antigens involves DNA-dependent RNA. Puromycin allowed synthesis of the T antigen which remained localized at the nucleolar membrane. This finding with puromycin suggests that the T antigen is a protein of low molecular weight. Virus antigen forming in the presence of mitomycin C, p-fluorophenylalanine, iododeoxyuridine, or fluorouracil was distributed atypically. These inhibitors caused the V antigen to be diffusely spread throughout the nucleus, or to be concentrated at the nuclear membrane.

Animals↗
PubMed1965

TUMOR AND VIRUS ANTIGENS OF SIMIAN VIRUS 40: DIFFERENTIAL INHIBITION OF SYNTHESIS BY CYTOSINE ARABINOSIDE.

Cells infected with the papovavirus SV40 not only synthesize viral antigen but also synthesize the specific nonviral antigen found in SV40-induced tumors. In the presence of the DNA antagonist cytosine arabinoside, infected cells fail to make viral antigen but still synthesize the tumor antigen. Iododeoxyuridine does not inhibit the synthesis either of tumor or of virus antigen but does prevent the development of infectious virus.

Antigens↗
PubMed1965

PHOTODYNAMIC INACTIVATION OF ENTEROVIRUSES.

Wallis, Craig (Baylor University College of Medicine, Houston, Tex.), and Joseph L. Melnick. Photodynamic inactivation of enteroviruses. J. Bacteriol. 89:41-46. 1965.-Enteroviruses are usually resistant to photodynamic inactivation, but they can be rendered completely photosensitive to proflavine at pH 9 to 10, if they are first purified by filtration through an anion resin. In addition, if enteroviruses are grown in cells maintained in a salt-glucose medium, they can be photosensitized. Of 38 enteroviruses tested, 10 were rendered completely photosensitive to proflavine, or toluidine blue, or both, and the remaining 28 viruses were sensitized, but to a lesser degree. The binding of dye to the virus can be reversed by lowering the pH.

Aniline Compounds↗
PubMed1965

CHROMATOGRAPHY OF POLIOVIRUS ON CALCIUM PHOSPHATE AND ITS APPLICATION TO THE IDENTIFICATION OF VACCINE PROGENY STRAINS.

Ozaki, Yoshikatsu (Baylor University College of Medicine, Houston, Tex.), Arwin R. Diwan, Mizuho Takizawa, and Joseph L. Melnick. Chromatography of poliovirus on calcium phosphate and its application to the identification of vaccine progeny strains. J. Bacteriol. 89:603-610. 1965.-Virulent and attenuated polioviruses were studied chromatographically with calcium phosphate as adsorbent and neutral phosphate buffer as eluent. For type 1, the attenuated LSc2ab strain and the virulent Mahoney strain were eluted at different salt concentrations. The peak of elution for the LSc2ab strain was at 0.3 m, whereas for the Mahoney strain it was at 0.05 m. No differences in elution pattern were noted with virulent and attenuated strains of poliovirus types 2 and 3. Except for a single instance, progeny strains isolated from vaccines or contacts 1 to 8 weeks after vaccination showed an elution pattern similar to the parent vaccine strain, or intermediate between the virulent and attenuated strains but still clearly distinguishable from wild-type virus. A virus population that possessed the same elution property as the virulent Mahoney strain could be separated from a number of progeny strains by chromatography. The ratio of this easily eluted population appeared to increase during the course of multiplication of vaccine virus in the human intestine. A virus population with the same elution profile as Mahoney seems to be present in the current LSc2ab oral polio vaccine, but as a very minor component. However, this component could readily be enriched by selecting for passage only those virus particles eluted at low salt concentrations. Heat-resistant, attenuated virus strains were selected from virulent type 1 strains by the Wallis-Melnick procedure of repetitive heating of progeny in AlCl(3). However, the elution pattern remained the same as that of the parent virulent virus.

Antigens↗
PubMed1965

DIFFERENCES IN CYSTINE DEPENDENCE AND CHROMATOGRAPHIC BEHAVIOR BETWEEN TWO TYPE 4 ECHOVIRUS STRAINS.

Wallis, Craig (Baylor University College of Medicine, Houston, Tex.), and Joseph L. Melnick. Differences in cystine dependence and chromatographic behavior between two type 4 echovirus strains. J. Bacteriol. 89:1310-1313. 1965.-Type 4 strains of echovirus, which are known to differ in the ease in which they can be neutralized, have been found to differ in other properties also. The prototype strain (Pesascek) differed from a readily neutralizable strain (DuToit) in that the Pesascek strain could be stabilized by cystine to thermal inactivation. Furthermore, the prototype virus required cyst(e)ine for growth under agar, whereas the DuToit strain was not affected. The viruses also reacted differently on anion-exchange resins. Pesascek virus had surface groups capable of exchanging for phosphate ions and, thus, was readily adsorbed, whereas DuToit virus was not bound by the resins under the same conditions. Only a small fraction of Pesascek virus was found to pass through the resin column. This fraction bred true, in that it yielded progeny that behaved like DuToit in not exchanging for phosphate. However, in neutralization tests, the progeny of this fraction retained the immunological property of the parent Pesascek virus.

Adsorption↗