Foster, John W. (University of Georgia, Athens), Robert M. Cowan, and Ted A. Maag . Rupture of bacteria by explosive decompression. J. Bacteriol. 83: 330–334. 1962.—A device is described for instantaneously rupturing bacteria and other cells in a closed system under controlled conditions by explosive decompression. With this device, 31 to 59% of Serratia marcescens , ranging up to 20 mg (dry wt) of cells per ml, were ruptured after nitrogen saturation at 1740 psi. Under similar conditions, 10 to 25% of Brucella abortus and Staphylococcus aureus were ruptured. Rupture of these organisms produced readily separable cell walls. Centrifugation in linear glycerol gradients was applied to further separate cell walls from debris. Mycoplasma gallinarum, Leptospira pomona , and Eimeria tenella (avian coccidia) oöcysts were also broken up by the decompression chamber. Pressure and duration of saturation of cells with gas affected rupture efficiency. Within the limits of this study, concentration of organisms and volume of suspensions did not have a definite effect.

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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.

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