Robert C. Cleverdon

The chemical composition and submicroscopic morphology of Mycoplasma gallisepticum, Avian PPLO 5969

Studies have been carried out on the chemical composition and morphological subunits of Mycoplasma gallisepticum (avian PPLO 5969). The morphological units which were identified were cell membrane, double-stranded DNA, ribosomes and soluble protein. DNA and RNA base ratios were determined as was amino acid composition. An analysis of the lipid components was carried out. A very striking feature of these cells is the very small size and low total content of DNA.

Fractionation of Mycoplasma cells for enzyme localization

Abstract Of six methods employed to disrupt cells of two Mycoplasma strains, only freeze-thaw and osmotic lysis permitted localization of NADH oxidase and ATPase activities. In one strain, NADH oxidase activity was confined to the soluble fraction, whereas it was in the membrane in the other; in both ATPase was largely membrane bound.

Effect of Terramycin on Fecal Microflora of Rats. I. Interrelation of Diet and Terramycin.

Summary 1. A study was made of changes in fecal microflora of albino rats engendered by changes in composition of diet, and by incorporation of terramycin in the 3 diets employed. The data were statistically analyzed as to ration effect, drug effect, interaction between ration and diet and reproducibility of experiments. 2. Diets per se, showed little or no effect in modifying the counts of total anaerobes and aerobes, L. acidophilus, or fecal streptococci. Nor was there a statistically significant interaction between terramycin and diet in these groups of organisms. Terramycin caused significant reductions of anaerobes, aerobes, and L. acidophilus and a marked increase of fecal streptococci regardless of ration. 3. The use of tergitol-7-agar containing T.T.C. was described for enumeration of E. coli in feces. The counts of E. coli were not affected by diet or terramycin per se, but a high degree of interaction between diet and terramycin obtained. The action of terramycin on the E. coli count was dependent on the type of ration fed, especially as evidenced by significant differences between terramycin supplemented high carbohydrate low protein ration and terramycin supplemented basal ration. 4. The high carbohydrate low protein diet resulted in a much lower count of Proteus spp. than either of the other 2 rations. Supplementation of all rations with terramycin resulted in a marked increase in numbers of Proteus spp. It was especially noted that the effect of terramycin was independent of the ration fed in this case.

The chemical composition of Dialister pneumosintes and the significance of the studies of small eubacteria

Abstract The percentage chemical composition (DNA, RNA, protein, lipid, and carbohydrate) of a small eubacterium resembles that of others, although the absolute number of biologically important molecules perforce markedly differs. In D. pneumosintes , the hundred million molecular weight of DNA seems to be adequate for coding proteins not in excess of 600, if the code is non-overlapping and non-degenerative. As in the case of the Mycoplasma qallisepticum , 2 this code seems short, and the real significance of these chemical studies can be appreciated only when more accumulate and are analyzed rigorously.

Some serological studies of the genera Corynebacterium, Flavobacterium, and Xanthomonas.

SummaryAntisera were prepared against members of three genera of bacteria:Corynebacterium, Flavobacterium andXanthomonas. Results of cross agglutination studies indicate the organisms form three groups which follow generic lines. With the corynebacteria, low cross reactivity, and with the xanthomonads, high titre and low cross reactivity facilitate differentiating the species examined. Three of flavobacteria appear to have quite similar antigenic components so that serologic diagnosis is not realized.

The irradiation of the pleuropneumonia-like organism A5969 with cobalt-60 gamma rays.

Results are reported from a study on the effects of radiation on the pleuropneumonia-like organism A5969, which is a very small cell. Data are presented on radioinduced clone inactivation and the role of desoxynucleic acids in inactivation.

Effect of Terramycin on Fecal Microflora of Rats. II. Therapeutic Level of Terramycin.

Summary 1. In the feces of albino rats, statistically significant reductions in counts of the total anaerobes, total aerobes and total lactobacilli were obtained by the addition of terramycin to the 3 diets employed. On the other hand, E. coli, Proteus spp. and, to a slight extent fecal streptococci, were increased in numbers. The increase in Proteus was unaccompanied by a decrease in E. coll. 2. The only ration effect was observed with the counts of fecal streptococci: the animals receiving the high protein rations showed a lower count than those receiving either the high carbohydrate or the basal ration. 3. The effect of terramycin upon counts of all organisms studied was found to be independent of ration in which the terramycin was incorporated (lack of statistically significant interaction between diet and terramycin). 4. The effects here reported were compared to the effects observed in a previous study.

Pigments of some flavobacteria, xanthomonads and corynebacteria

SummaryA study of the spectral properties of intracellular pigments in clarified cellular suspensions of 11 flavobacteria, 9 xanthomonads and 2 corynebacteria showed that the flavobacteria are most heterogeneous in their absorption maxima (390, 400–410, 420–424, 476–478 mμ). The corynebacteria absorbed strongly at 400–404 mμ, indicating some similarity to the flavobacteria. The xanthomonads generally absorbed strongly at 404–406 mμ. In these genera, the general absorption properties removed from the procedure the anticipated taxonomic application, although after establishing other features, such study might be of profit especially in the case of designation ofXanthomonas.