The cytology and life cycles of the Actinomycetes recently have received critical study. The presence of an apparent life cycle has been shown in Streptomyces (Kijeneberger-Nobel, 1947) and Actinomyces (Morris, 1951). McClung (1950) stained nuclear-like bodies and studied the proes of fragmentation in several species of Nocadia. The investigation, however, omitted a careful examination of germination, cytology, and division of the coccoidal forms. These recent cytological studies have relied primarily on the acid-Giemsa nuclear stain and various cell wall stains, some of which will not stain cross septa. This investigation was undertaken to determine the cytology of the genus Nocadia and other Actinomyetes by using the Chance crystal-violet nuclear stain, cell wall stains, and phase microscopy. The crystal-violet nuclear stain does not involve acid hydrolysis or other harsh treatment and should prove of value in clarifying the nuclear cytology of the Actinomycetes. AT~19L AND METHODS Nocadia corallina (ATCC-4273), which readily fragments into coccoidal forms, was chosen for detailed study. Nocardia blakwelli (ATCC4-846) and Streptomces grieueu (ATCC-10137) were studied to a leser extent for comparisOn pur
well without swarming on FePA, although they swarmed on Brain Heart Infusion Agar. When cultured in FeP broth, the bacteria were nonmotile or sluggishly motile. Flagella stains (Liefson, Atlas of Bacterial Flagellation, Academic Press, Inc., New York, 1960, p. 3-4) of both broth and agar cultures after 24 hr at 32 and 37 C indicated that flagellation was inhibited or delayed in FeP media and not in brain-heart media (Fig. 1). With incubation times of 48 hr or more, flagella appeared along with limited fingerlike spreading.
The organism used was isolated from the soil and grown on glucose agar. In size and fermentation it corresponds in a measure with Bacillus mesentericus. Only the R type was used since the staining reaction of the S type was not satisfactory. A twelveto thirteen-hour culture was used as the parent culture. Since stains of the growing culture were to be made at different time intervals, as many transfers were made as time intervals, thus giving a separate culture for each staining period. After the transfers were made cells were removed from the parent culture and stained (figs. 1 and 2). Some of these cells stained throughout. Others had more heavily stained structures within the cytoplasmic region. The arrangement of these structures, within limits, constituted a type of configuration. The cells from the two-hour culture (fig. 3) may or may not stain. Some of the figures resemble in a measure those characteristic of the parent cells while others may contain one or even two spherical bodies. Some of these cells stain rather uniformly throughout, while others give a motley effect. A more deeply stained spherical body may appear in cells otherwise uniformly stained. Where two spherical bodies appear they may be equal or unequal in size and occur separately or partially united. The wall region of some cells remains unstained. The stoning pic
Since the discovery of heavy water, many experiments have been made to determine its influence upon living organisms. Although some of these investigations have shown little effect (Melot, 1934;Rea and Yuster, 1934), others (Lewis, 1933;Harvey, 1934;Ussing, 1935) reported a depressing action on the growth of plants and animals. The pioneer experiment in this field was carried out by Lewis (1933). Tobacco seed (Nicotiana tabacum var. purpurea) would not germinate in 100 per cent heavy water but did germinate very slowly in a 50 per cent concentration. Pratt and Curry (1937) found that wheat seedlings and the lower parts of buds of Kalanchoe daigremontiana grew only 0.025 as rapidly in 99 per cent heavy water as in normal water. The osmotic effects of heavy water on the leaf cells of Nitella clavata was studied by Brooks (1937), who found that the cells shrank in heavy water and expanded in normalwater. It was concluded that heavy water was hypertonic to the cells.Fox, Cupp, and McEwen (1936) measured the growth of diatoms in 1 per cent heavy water and in filtered sea water. They reported a lag of 16 per cent in the growth rate of Nilzschia bilabata over a period of 12 days in heavy water. Freshly collected Spirogyra placed in 0.06 per cent heavy water by Barnes (1933) was characterized by lack of movement, much less cell disjunction, and greater longevity than the controls in distilled water. A study of the influence of heavy water upon the rate of photosynthesis was made by Craig and Trelease (1937) upon Chlorella vulgaris suspended in a carbonate-bicarbonate buffer. Using the evolution of oxygen as a measure of photosynthesis, they found a decrease in the rate of 0.41 in 99.9 per cent heavy water. Using the same organism, Pratt (1938) found the decrease in growth to be in inverse linear proportion to the concentration of deuterium oxide up to 75 per cent, at which concentration practically no growth occurred.Taylor, Swingle, Eyring, and Frost (1933) showed that 92 per cent of heavy water influenced the life processes of tadpoles, Rana clamitans; fish, Lebestes reticulatus; flatworms, Planaria maculata; and the protozoan, Paramecium caudatum. The tadpole died within an hour; the fish within 2 hours; the flatworm within 3 hours; but the Paramecium lived 48 hours. When the concentration was decreased to 30 per cent, no effect could be detected on the tadpoles, fish, or flatworms over a period of 48 hours. When the white mouse was subjected (Barbour, 1935) to a 99 per cent solution of heavy water, the metabolism was slowed
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