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K. Wolf

Publications and source records attributed to K. Wolf.

At least 91 records · Page 5Linked to original sources
USGS1970

Salmonid viruses: Double infection of RTG-2 cells with Egtved and infectious pancreatic necrosis viruses

Egtved and infectious pancreatic necrosis (IPN) viruses were applied at high multiplicity alone and in combination to RTG-2 cells in liquid medium. Procedures were used which selectively suppressed one or the other virus, and the yields were determined after 64 hours at 15°C. The viruses showed an increase of 280 to 450 times the immediate post-adsorption level. Plaques of IPN and Egtved viruses showed some differences which can be helpful in distinguishing between the two agents. Detailed methods and results are given.

Archiv Fur Die Gesamte Virusforschung↗
USGS1969

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.

Applied Microbiology↗
USGS1969

Quantitative comparison of peritoneal washes and feces for detecting infectious pancreatic necrosis (IPN) virus in carrier brook trout

Paired fecal samples and peritoneal washes were taken from 300 18-month-old brook trout for determining their relative value in detecting IPN virus. The testing of feces revealed 14 times as many carriers as were found by peritoneal washes. Initial examinations showed at least 63% of the fish to be carriers of the virus, but 30% more were detected in four additional tests. Fecal output of virus from 37 fish was quantified up to five times during a period of 7 months which included the spawning season. Although there were exceptions, fish with high outputs of virus tended to maintain that level, and low titer carriers tended to yield small amounts, and in some instances, no virus. Tests of fecal extracts which were pooled from 5, 10, and 15 fish showed that virus was readily detected in all three. For economy and efficiency, the use of 10- or 15-sample pools is recommended for determining the presence of IPN in fish.

Journal of the Fisheries Research Board of Canada↗
USGS1968

Ultrastructure of lymphocystis virus

Lymphocystis virus obtained from bluegills ( Lepomis macrochirus ) was cultured in the permanent bluegill cell line BF-2 and examined by electron microscopy in ultra-thin sections of cell cultures and in negative-contrast preparations from cells and from centrifuged culture medium. According to negative-contrast preparations, the icosahedral virions have an overall diameter close to but not exceeding 300 m μ . Delicate filaments seem to issue from the vertices. In collapsed virions, an ordered array of morphological units was seen. Positively contrasted virions in ultrathin sections show a shell with three dark (heavy metal-stained) layers alternating with and separated by two clear layers. The acquisition of an additional outer membrane during release from the cell, as found in African swine fever virus, was never seen. Morphologically, lymphocystis virus is considered to be closely related to Tipula iridescent virus.

Journal of Virology↗
USGS1968

Infectious pancreatic necrosis: Selection of virus-free stock from a population of carrier trout

Infectious pancreatic necrosis (IPN) is a virulent disease of young trouts and is easily transmitted from infected animals through water and with eggs. At present, the most effective control measure consists of propagation of specific pathogen-free stock. Methods are described for using fish cell cultures to detect IPN virus in peritoneal washes, feces, and gonadal fluids and thereby to identifiy carrier and non-carrier fish. The procedures were used to derive virus-free progeny from a hatchery trout population containing about one-third carrier fish. The progeny were reared to maturity, spawned for 3 successive years, and at each spawning they proved free of virus. Recommendations and precautions are given for those who may wish to apply the procedures.

Journal of the Fisheries Research Board of Canada↗
USGS1968

Book Review: Transmission of viruses by the water route by Gerald Berg, ed.

This "book" is a collection of 31 carefully edited reports which are based upon presentations of highly qualified persons who were, for the most part, participants in a 3-day symposium held in 1965 and sponsored by the research branch of what is now the Federal Water Pollution Control Administration (FWPCA).

Transactions of the American Fisheries Society↗
USGS1967

Low-temperature incubation using a water supply

Cell and tissue culture has been concerned primarily with homiothermic vertebrate cells which require incubation at about 37 C, and there is a great variety of incubators designed to maintain temperatures which are usually above ambient. The culture of poikilothermic vertebrate cells--and invertebrate, plant, and some microbial cells--can often be carried out at ambient temperatures, but for some work cooler conditions must be provided. Variety among the so-called low-temperature incubators is somewhat restricted; there are no small units, and all require a power source to maintain temperatures below ambient. We have used a gravity-fed water supply for 5 years to provide trouble-free, constant, low-temperature incubation of stock cultures of fish and amphibian cells. Though it is but a small part of our low-temperature incubator capacity, it has no power requirements and it provides maximal protection against temperature rises which could be lethal to some of the cell lines. Though the system has limitations, there is a considerable likelihood that the domestic water supply in other laboratories can also be used to provide low-temperature incubation.

Applied Microbiology↗
USGS1966

The fish viruses

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Advances in Virus Research↗
USGS1966

Lymphocystis virus: Isolation and propagation in centrarchid fish cell lines

A virus from fish with lymphocystis disease was isolated in fish cell cultures. Eleven serial transfers were made and the pathognomonic lymphocystis cells were produced in vitro in each transfer. Fish inoculated with 6th- and 9th-passage material developed the disease, and virus was reisolated from them.

Science↗