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Biomedical subjects

K Wolf

Publications and source records attributed to K Wolf.

At least 235 records · Page 13Linked to original sources
PubMed1973

Fish viruses: buffers and methods for plaquing eight agents under normal atmosphere.

A universal procedure was sought for plaque assay of eight fish viruses (bluegill myxovirus, channel catfish virus, eel virus, Egtved virus, infectious hematopoietic necrosis virus, infectious pancreatic necrosis virus, lymphocystis virus, and the agent of spring viremia of carp (Rhabdovirus carpio), in dish cultures of various fish cells. Eagle minimal essential medium with sodium bicarbonate-CO(2) buffer (Earle's salt solution) was compared with minimal essential medium buffered principally with tris (hydroxymethyl)aminomethane or N-2-hydroxyethylpiperazine-N'-2'-ethanesulfonic acid at a pH or in the range of 7.6 to 8.0 depending upon temperature. Five fish cell lines collectively capable of replicating all fish viruses thus far isolated were tested and quantitatively found to grow comparably well in the three media. Two-phase (gel-liquid) media incorporating the various buffer systems allowed plaquing at 15 to 33 C either in partial pressures of CO(2) or in normal atmosphere, but greater efficiency and sensitivity were obtained with the organic buffers, and, overall, the best results were obtained with tris(hydroxymethyl)aminomethane. Epizootiological data, specific fish cell line response, and plaque morphology permit presumptive identification of most of the agents. At proper pH, use of organic buffers obviates the need for CO(2) incubators.

Air↗
PubMed1973

Evidence for an extrakaryotic mutation affecting the maintenance of the rho factor in yeast.

A newly isolated, temperature-sensitive mutant of a haploid strain of Saccharomyces cerevisiae is described. Its shift to nonpermissive temperature (35 C) resulted in an irreversible change to rho(-), causing, within four to six generations, more than 90% of the cells to form petite colonies. Genetic analysis revealed extrakaryotic inheritance of this temperature-sensitive mutation. Data presented indicate mutation of a gene in the mitochondrial deoxyribonucleic acid affecting the maintenance of the rho factor.

Crosses, Genetic↗
PubMed1971

Channel catfish virus: a new herpesvirus of ictalurid fish.

Channel catfish virus was studied in ictalurid fish cell culture, the only system of fish, amphibian, avian, and mammalian cells found to be susceptible. Channel catfish virus infection resulted in intranuclear inclusions and extensive syncytium formation. Replication occurred from 10 to 33 C, but not higher. Best growth was from 25 to 33 C, and the amount of virus released nearly equalled the amount which remained cell-associated. The virus was labile to lipid solvents, and indirect determinations with labeled precursors and a metabolic inhibitor showed evidence of deoxyribonucleic acid. Electron microscopy showed progeny virus, about 100 nm in diameter, in various stages of development in cell nuclei by 4 hr. Present also were nuclear masses of exceptionally electron-dense lamellar material, with a unit dimension of 10 to 15 nm. Virus was enveloped at the nuclear membrane and in cytoplasmic vacuoles, resulting in virions having a diameter of 175 to 200 nm. Negative staining demonstrated icosehedral symmetry and 162 capsomeres. Our data indicate that channel catfish virus is a herpesvirus.

Animals↗
PubMed1969

Infectious pancreatic necrosis virus: lyophilization and subsequent stability in storage at 4 C.

Infectious pancreatic necrosis virus (ATCC strain VR # 299) was lyophilized with different additives and stored at 4 C. Ampoules were assayed at 2 days, at 1, 3, and 6 months, and at 1, 3, and 4 years. Processing losses were least and subsequent maintenance of infectivity was best in skim milk, lactalbumin hydrolysate, and lactose. Quantitative data are given in tabular form.

Albumins↗