Escherichia coli cultures in the logarithmic phase or resting were treated with various concentrations of ozone in saline solution. Approximately 2 X 107 molecules of ozone per bacterium killed 50% of the cells. Ozone caused leakage of cell content into the medium, and lysis of some cells. Low concentrations of ozone did not react with the glutathione within the cells, although reaction with glutathione in solution was immediate and stoichiometric. The effect on nucleic acid within the cells was to change the solubility and to cause the release of ultraviolet-absorbing material into the medium. Ozone attacked the ring structure of the base or the carbohydrate only when the substance was in the medium. Nucleic acids released into the medium were reabsorbed by cells which were not lysed. Viable cells resumed growth immediately, and grew at rates determined by the nutrients either added to the medium or which resulted from leakage and lysis of nonviable cells. It is postulated that the primary attack of ozone was on the cell wall or membrane of the bacteria, probably by reaction with the double bonds of lipids, and that leakage or lysis of the cells depended on the extent of that reaction.

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This paper emerged from discussions following the Bachelor Gorilla 2000 Workshop Facility Design sessions. Although many ape facility design features are common to all gorillas, the purpose of this paper is to provide an overview of special needs of bachelor gorillas. For example, managing escalating aggression between maturing or silverback males may require a high degree of caregiver intervention and thus easy access to gorillas both on- and off-exhibit is beneficial. Facility design features that reduce contact aggression, increase affiliation, provide visual barriers or escape routes, and allow safe outlets for species-typical behavior are essential to the successful management of bachelor gorilla groups in zoos. Such provisions permit caregivers the ability to constantly monitor and modify the zoo environment to meet rapidly changing husbandry needs. Creatively designed habitats and continuing research on bachelor group dynamics will undoubtedly allow zoo managers to maintain all gorilla groups in an environmental and social context that enhances well-being over the long term.

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