Elevated Incubation Temperature Research Articles

Influence of Some Physical Factors on Survival of Marek's Disease Vaccine Virus

Cell-associated Marek's disease (MD) vaccine was suspended at dilutions normally used for vaccination in seven commercially available diluents and in tryptose phosphate broth. The stability of diluted vaccines was determined by assay in cell cultures subjected to 0 to 37 C for 0 to 90 minutes. Optimum holding temperatures for MD vaccine virus survival varied with the specific diluents employed. Some diluents afforded greatest survival when dilution was at 0 C and held at 0 C, while others performed best when dilution was at 25 C followed by cooling and holding at 0 C. Diluents which allowed greatest survival when tested at 37 C also performed well under other temperature regimes. Spectinomycin dihydrochloride pentahydrate and various buffering compounds were added to commercial diluents used for diluting MD vaccine. Additives producing osmolality of 745 mOsm/kg and higher markedly reduced vaccine virus survival. The adverse effects of high osmotic pressure were accentuated by extended holding time, elevated incubation temperature, and physical manipulations including mechanical mixing or expressing through a syringe and needle. Satisfactory MD vaccine virus survival was afforded by a commercial diluent especially formulated to accommodate the pH osmolality changes produced by adding spectinomycin dihydrochloride pentahydrate.

Membrane filter technique for enumeration of Pseudomonas aeruginosa.

A membrane filter procedure for the quantitation of Pseudomonas aeruginosa (mPA procedure) has been developed. Through the use of inhibitors and an elevated incubation temperature, the level of background microbial flora was decreased approximately 10,000-fold. Using P. aeruginosa cells suspended in sea water and held for 24 hr, between 70 and 100% of the "viable" cells could be recovered by the mPA procedure. Assay variability was found to be insignificant. The recoveries of P. aeruginosa from surface (fresh and salt) waters, potable waters, and sewage by the mPA procedure exceeded those obtainable by current methods. Subsequent to its development and evaluation, the mPA procedure was used at three other laboratories for the enumeration of P. aeruginosa in potable and recreational waters and in sewage samples. It was found amenable to routine use, and confirmation of typical colonies approached 100%.

Membrane Filter Technique for Enumeration of Pseudomonas aeruginosa

A membrane filter procedure for the quantitation of Pseudomonas aeruginosa (mPA procedure) has been developed. Through the use of inhibitors and an elevated incubation temperature, the level of background microbial flora was decreased approximately 10,000-fold. Using P. aeruginosa cells suspended in sea water and held for 24 hr, between 70 and 100% of the "viable" cells could be recovered by the mPA procedure. Assay variability was found to be insignificant. The recoveries of P. aeruginosa from surface (fresh and salt) waters, potable waters, and sewage by the mPA procedure exceeded those obtainable by current methods. Subsequent to its development and evaluation, the mPA procedure was used at three other laboratories for the enumeration of P. aeruginosa in potable and recreational waters and in sewage samples. It was found amenable to routine use, and confirmation of typical colonies approached 100%.

Effect of elevated incubation temperature on non-structural arbovirus proteins

Effect of elevated incubation temperature on non-structural arbovirus proteins

The Relationship of Hyperthermia to Liver Growth and Liver Glycogen in the Chick Embryo

INTRODUCTIONNUMEROUS studies have indicated that elevated incubation temperature for the chick embryo results in visceral overgrowth and protrusion of the viscera into the body stalk (celosomia), various other congenital malformations and growth acceleration. Ancel and Lallemand (1941) reported the production of visceral overgrowth and celosomia in chick embryos incubated at 39.0°C. during the third through the sixth day of incubation. This same malformation was produced in the chick embryo by Delphia and Eveleth (1961) from continuous incubation temperature of 40.0°C. Alsop (1919) and de la Cruz et al. (1966) recorded numerous congenital malformations in chick embryos incubated at 40.0°C. Rott (1957a, b) observed that incubation of the chick embryo at 38.5°C. accelerated growth during the first half of incubation. Delphia and Elliott (1965) using a temperature of 40.0°C. during the third through the sixth day and continuously, found lowered myocardial glycogen levels.The present study is concerned with the .

Persistent, noncytocidal viral infection: nonsynchrony of viral and cellular multiplication.

Walker, Duard L. (University of Wisconsin Medical School, Madison), Ping-Ping Chang, Robert L. Northrop, and Harry C. Hinze. Persistent, noncytocidal viral infection: nonsynchrony of viral and cellular multiplication. J. Bacteriol. 92:983-989. 1966.-In cultures of human conjunctive cells persistently infected with mumps virus (C-M cultures), the degree to which viral multiplication is linked to cell multiplication was examined. First, cell multiplication was inhibited. This resulted in a 10-fold increase in virus-excreting cells in the culture and an 80-fold increase in virus in the medium as compared with vigorously growing control cultures. Second, by use of elevated incubation temperature, virus multiplication was inhibited without slowing multiplication of the cells, and uninfected cells that appeared in the culture were protected by virus antiserum. This resulted in accumulation of antigen-free cells and, in one experiment, in elimination of the virus. Evidence indicated that uninfected cells accumulated as a result of dilution of virus by repeated cell divisions, but not as a result of selection of uninfected cells. These data indicate that viral multiplication in the C-M system is not closely linked to cell multiplication and that each can proceed at a rate different from the other.

Peptone-Dextrose Broth for Use in Studies of Antibacterial Activity.

Summary(1) Peptone-Dextrose broth (PD), made with currently available samples of Neo-, Proteose and Pfanstiehl peptones, has failed to support growth of beta hemolytic streptococcus strain C 203 at the elevated incubation temperatures which are required for demonstration of bactericidal activity with low concentrations of sulfanilamide. (2) A modified PD broth containing 2.0% Tryptose and 0.1% Pfanstiehl peptones together with 0.2% dextrose and 0.5% sodium chloride buffered at pH 7.2 has been found to be satisfactory for use in studies of bactericidal activity. (3) Results obtained with this modified broth confirmed the conclusions previously drawn in regard to the critical relationship between temperature and the bactericidal activity of sulfanilamide.