Growth characteristics of Mycobacterium avium and group III nonphotochromogenic mycobacteria in HeLa cells

Brosbe, Edwin A. (Veterans Administration Hospital, Long Beach, Calif.), Paul T. Sugihara, and C. Richard Smith. Growth characteristics of Mycobacterium avium (avian) to group III nonphotochromogenic mycobacteria in HeLa cells. J. Bacteriol. 84:1282-1286. 1962.-The close relationship of Mycobacterium avium (avian) to group III nonphotochromogenic (Battey) strains of mycobacteria stimulated interest in their behavior in HeLa cells. In general, the avian strains grew more slowly than the Battey strains; 10 of 17 avian and 3 of 12 Battey strains required more than 7 days to exhibit abundant intracellular growth. Branching filaments were observed with variable frequency in all of the strains studied. Branching occurred at right angles, and was seen more often with the Battey strains and the avian strains isolated from swine. These observations indicate that the growth rate and growth pattern of avian and Battey mycobacteria in HeLa cells are not sufficiently specific to facilitate distinguishing the two species from each other.

Some theoretical aspects of osmium tetroxide fixation with special reference to the metaphase chromosomes of cell cultures

Fixation of cell cultures with 1 per cent OsO₄ at constant pH and tonicity but variable cationic valence and dielectric constant causes profound changes in metaphase chromosomes. It is possible to make them disappear, flocculate, or show little change from the living cell in the phase contrast microscope. Conventional fixation for the electron microscope causes almost complete disappearance of metaphase chromosomes in phase contrast. Reasons for this behavior are discussed. It is postulated that intermolecular distances and consequently internal structure in chromosomes are governed by the same forces that govern these distances in colloidal sols.

The mammalian cell-virus relationship. VI. Sustained infection of HeLa cells by Coxsackie B3 virus and effect on superinfection

Sustained infection of HeLa cells by Coxsackie B3 virus, dependent on presence of viral inhibitor in culture medium, was achieved. Persistent treatment of carrier cultures with anti-Coxsackie B3 hyperimmune monkey serum eventually eliminated virus from carrier cultures indicating that a lysogenic virus-cell relationship was not operative. Free virus was produced continuously by carrier cultures despite washing and neutralization with antiserum to eliminate free virus temporarily. In carrier cultures, about 1.5 to 1.9 plaque-forming units of virus per cell were cell-associated; approximately 6 per cent of this cell-associated virus was not neutralizable by antiserum. In growth medium containing anti-B3 antibody, cells from carrier cultures formed colonies as efficiently as cells from B3-cured cultures. Assays of carrier cultures for infectious centers indicated that less than 1 per cent of cells produced free infectious virus. The Coxsackie B3 virus-carrier state appeared to represent surface residence of B3 virus on the majority of carrier cells with restriction of productive infection to a small proportion of the population. Coxsackie B3 carrier HeLa cultures, unlike control cultures, were not destroyed by challenge with Coxsackie B1, B3, or B5 viruses. The B3 carrier state did not interfere with superinfection by herpes, vaccinia, and types 1 to 3 polioviruses. In contrast to parental or B3-cured lines, B3-carrier HeLa cultures superinfected with Coxsackie B1 virus produced no significant virus, and cultures superinfected with B5 viruses produced new virus to a limited extent only. Specific interference with Coxsackie virus superinfection by the B3-carrier state of HeLa cells was shown to be attributable to failure of attachment in the instance of Coxsackie B1 virus, and failure of penetration and/or eclipse in the instance of B5 virus. The interfering effect was circumvented successfully by superinfection of carrier cells with ribonucleic acid extracted from Coxsackie B1 and B5 viruses.