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Geology topics

K. Wolf

Publications and source records attributed to K. Wolf.

At least 73 records · Page 4Linked to original sources
USGS1974

Myxosoma cerebralis: Isolation and concentration from fish skeletal elements - Sequential enzymatic digestions and purification by differential centrifugation

An effective sequential procedure for recovery of Myxosoma cerebralis spores from infected trout was developed, and quantification of spores was carried out at each step of release and concentration. Methods are described for fresh and frozen material. Effective concentration of from 1100- to 9000-fold and an estimated efficiency of recovery of about 80% has been achieved. Tabular and graphic data are presented with recommendations for diagnostic applications. The immediate applications of these procedures are in implementing more effective detection and in preparing antigen for the immunologic studies that should provide the most sensitive detection.

Journal of the Fisheries Research Board of Canada↗
USGS1974

Myxosoma cerebralis: Comparative sensitivity of spore detection methods

Physical and biophysical methods of detecting spores of Myxosoma cerebralis were used in sequence on 87 individual fingerling rainbow trout ( Salmo gairdneri ) from two populations with a low incidence of infection. Physical methods of releasing spores from the organs of equilibrium, gill arches, or the axial skeleton gave an estimated rate of infection of 2.3–4.6%. Each succeeding step — pepsin digestion, trypsin digestion, and differential centrifugation through 55% dextrose solution — revealed additional infected fish. The final step of the sequence detected 10.5 times more infected fish than were found by examination of the organs of equilibrium or the axial skeleton with physical means; the true incidence was at least 24.1%. Procedures are described for using biophysical methods on 60-fish pools for hatchery inspection work and also on the more bony skeletons of mature fish.

Journal of the Fisheries Research Board of Canada↗
USGS1973

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.

Applied Microbiology↗
USGS1973

Fish viruses: Isolation and identification of infectious hematopoietic necrosis in eastern North America

Infectious hematopoietic necrosis virus (IHNV) was isolated from diseased fingerling rainbow trout ( Salmo gairdneri ) from a hatchery in West Virginia. Clinical signs, histopathologic findings, and origin of eggs provided a basis for diagnosis, and virus was isolated and presumptively identified by plaque characteristics. Serum neutralization tests provided positive identification of the agent as IHNV, and electronmicroscopy showed its rhabdovirus morphology. Experimental infections resulted in signs of IHNV and death; test fish had characteristic histopathologic alterations and appropriate virus titers. This is the first completely documented occurrence of IHNV beyond the Pacific Northwest.

Journal of the Fisheries Research Board of Canada↗
USGS1972

Fish rhabdoviruses: Morphology and ultrastructure of North American salmonid isolates

The morphology and ultrastructure of three North American salmonid pathogens, Oregon sockeye salmon, chinook salmon and infectious hematopoietic necrosis viruses, were examined by thin sectioning and negative staining after growth in fathead minnow cells at 10 ° C. The viruses matured at the plasma membrane of these cells. They were approximately 170 nm in length, 70 nm in width and had internal striations with a periodicity of 5.5nm. They were rounded on one end and planar on the other ( i.e. , bullet shaped). By morphological criteria, these viruses are rhabdoviruses with dimensions and ultrastructural features similar to vesicular stomatitis virus.

Archiv Fur Die Gesamte Virusforschung↗
USGS1971

Salmonid viruses: Infectious pancreatic necrosis virus

Epizootics occurred among young trout in France, and the behavior and symptoms suggested infectious pancreatic necrosis (IPN) virus. Specimens preserved in glycerol were sent to the U.S.A. for virological examination. Virus was isolated from four of five lots, but neutralization with antiserum against ATCC VR299 strain IPN virus was incomplete. Electron microscopy, bioassay, histopathology, and serology were used to identify the viruses. The results showed the agents to be new strains of IPN virus with distinctive antigenicity and heretofore unknown lability at 4°C and marked vulnerability to a single freezing and thawing. A method of improving stability in storage was found. Electronmicrographs, tabular and graphic data are presented.

Archiv Fur Die Gesamte Virusforschung↗
USGS1971

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.

Journal of Virology↗