Hilda Kurtz

Initial stages of the interaction of HeLa cells with poliovirus.

As a c(~nsequence of the usual interaction of viruses and cells, one detects an initial loss of viral activity, a viral increase and destruction of cells. I n such cases the reaction may be followed in terms of any of the resultant~effects, ttowever, all interactions may not b e productive of virus; nor result in cellular ,destruction and viral activity m a y lend itself .to competing reactions. Td follow the reaction by a single effect may preclude the observation of unexpected phenomena. The present study is centered upon the cytopathogenic effect of the poliovirus and for this reason its reaction with the HeLa cell is followed primarily in terms of cellular destruction. For this purpose a method has been developed for quantitating cellular injury. By the application of the method, the kinetics of two early phases of the interaction of virus and cell have been investigated.

A new host-virus system.

Summary A new host-virus system is described. The WS strain of Type A influenza virus was adapted to culture in the Ehrlich ascitic carcinoma of mice. This adapted strain of virus has been maintained through 38 serial passages in this tissue. The growth characteristics during a single passage have been described. Associated with the multiplication of this virus is a loss of viability of the host cell. The effect of this phenomenon on the course of development of an established ascitic tumor has been followed. The importance of this new host-virus system as a tool for the study of the mechanism of viral multiplication is discussed.

RNA dependent DNA synthesis in cell free preparations of human leukemia cells

Abstract A cell free preparation of human leukemic cells, grown in tissue culture, incorporated H 3 -thymidine phosphate into an acid insoluble product which was rendered acid soluble by the action of DNAase but not KOH or RNAase. RNAase, if added before incubation of the reaction mixture, prevented incorporation of the isotope into the product. For maximum incorporation Mg and all four deoxyribonucleotide triphosphates must be present. The enzyme has the properties of an RNA dependent DNA polymerase.

Cationic Modulation of the Inactivation of Poliovirus by Heat

The rate of inactivation of purified poliovirus was determined at 113 F (45 C) in Ihe presence of various concentrations of magnesium ions. The rates could be predicted over a 50-fold range of magnesium ion concentrations from the expression, log V0/V = t k/KMn + 1. The latter was derived assuming that a fraction of the virus reacts with the cation to form a complex completely stable at 113 F (45 C). The data could be described by a Hill-type equation wherein the logarithm of a function of the degree of inhibition of viral inactivation was found to bear a linear relalionship to the logarithm of the concentration of magnesium ion. The interpretation of this plot is that the rale of inactivation of poliovirus at 113 F (45 C) is determined largely by a single vital reaction which can be blocked by a single magnesium ion.

A covalently linked DNA-RNA molecule from human leukemia cells

An enzyme complex was prepared from the cytoplasm of a continuous line of monocytic human leukemia cells isotopically labeled in culture. Such preparations carry out RNA dependent DNA synthesis using endogenous primers and templates and contain radioactive RNA and DNA. The endogenous [3H]-thymidine labeled DNA in these preparations was characterized by sedimentation in Cs2SO4 and neutral sucrose density gradients in conjunction with heat and alkali treatments and digestion with RNase. The resulting data support a view that a portion of the DNA is covalently linked to a larger piece of RNA in a molecule with a sedimentation coefficient of approximately 24S. This in turn may be hydrogen bonded to additional DNA in the native state.

Effects of Cations and Organic Compounds on Inactivation of Poliovirus with Urea, Guanidine, and Heat

Summary Cations stabilized poliovirus against inactivation by urea (0.5-4.5 M) and heat (45°) but to sensitize it to inactivation by guanidine, indicating that urea and heat affect the same structure on the virion which is different from those affected by guanidine. Choline, methionine, betaine, and even guanidine had similar effects as cations. However, certain low concentrations of choline and methionine were also able to partially prevent guanidine inactivation. The action of these compounds on the reactivity of po-liovirion is discussed in terms of induced conformational changes of the viral capsid protein.

THE ACTION OF TERRAMYCIN ON THE GROWTH OF STRAINS OF INFLUENZA, HERPES SIMPLEX, AND RABIES VIRUSES IN CHICK EMBRYOS AND MICE

‘The value of terramycin as an antibacterial agent has been shown in previous publi~ationsl-~ and in other reports presented in this monograph. It is the purpose of this paper to describe some experiences with terramycin salts and how they influenced the course of a few experimental virus infections. The bulk of our attention has been focused on the action of this drug in influenza virus infections. Mention will also be made, however, of some work done on two strains of herpes simplex virus and a strain of rabies virus. Malerial and Melhods. The sodium terramycin salt was highly soluble in phosphate saline buffer (pH 7.4). Consequently, this diluent was used in all chick embryo experiments. The final pH of the solutions used was between 8.3 and 8.6. The material inoculated subcutaneously in mice was dissolved in distilled water and had approximately the same pH. All solutions were made up fresh for each inoculation. The viruses used and their passage history are as follows: PR8 strain of type A influenzaFerrets 198, Mouse 285, Egg 64, for egg inoculation and F 198, M 846 for mouse inoculation; Lee strain of Type B influenza virus, M 137E141; Armstrong strain of herpes simplex virus, M 49E31, M5E6; HF strain of herpes simplex virus, M?M5; rabies virus, passed in mice with passage once a month in rabbits, number of passages not known. The volume of drug solution injected in all instances was 0.2 ml. and contained the desired dosage of terramycin. The interval between injection of terramycin and virus was varied and is discussed under results. Most injections of both virus and terramycin were made into the allantoic cavity of 10 to 12 day-old embryos. A few tests utilizing the yolk sac as the route of injection were done and resulted in more deaths than by the allantoic method. In all tests, simultaneous controls of drug alone and virus alone were also carried out. Furthermore, preliminary tests for the toxic effect of drug alone were carried out in groups of 8 to 20 eggs. Influenza virus was diluted 10-fold in nutrient broth, and herpes simplex in 10 per cent horse serum in saline. The volume of inoculum was 0.2 ml., and 4 to 6 eggs were used for each dilution of virus. The eggs were incubated for 40 hours a t 35°C. for influenza and 72 hours at 37°C. for herpes. The eggs were chilled for 2 hours at 4°C. in those instances where allantoic fluids were to be removed. Such fluids were tested by diluting 1 to 4 with Experimenls with Chick Embryos.