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Lysozyme has been tritiated by the free-radical interceptor method, which involves reaction of the carbon free radicals, resulting from gamma-irradiation of the lyophilized protein in a vacuum, with tritiated hydrogen sulfide. This technique resulted in a high yield of tritiated enzyme which was chromatographically indistinguishable from the native protein. To characterize this material with respect to its tritium distribution, it was first reduced, carboxymethylated, and digested with chymotrypsin. The peptides were separated and purified by ion exchange chromatography and electrophoresis and then analyzed to determine the specific activities of 78 of the 129 residues in the protein chain. The tritium was found to be broadly distributed, with only 12 residues apparently devoid of label. The relative specific activity, defined as the ratio of the specific activity of a given residue to the average specific activity for all residues of the same kind within the protein, did not exceed the value of 3.73 for isoleucine at position 88. A distinct spatial relationship is seen among the more heavily labeled residues when these results are related to the x-ray diffraction model of lysozyme. Thus, residues 16, 18, 19, 21, 23, 29, 31, and 32 may be grouped with 105, 110, 113, and 115; these highly labeled residues are close to a strongly hydrophobic region. Another heavily labeled area involves residues 50, 54, 57. 83, 84, and 88. In addition, residues 1 and 6 at the amino end of the chain are heavily labeled, as are 118, 121, and possibly 119 at the carboxyl end. This distribution of tritium appears to reflect the secondary free-radical distribution in the irradiated protein. These observations confirm previous indications that the secondary distribution is influenced by the conformation of the protein molecule.

Edwardsiella tarda was isolated from a sea lion and 2 alligators on 3 separate occasions. The 3 isolates were not serologically identical. Specific pathologic effects of E. tarda could not be determined.

A naturally occurring anaplasma-antibody complex was detected by exposing erythrocytes of infected cattle to fluorescein-labeled bovine antiglobulin. This technique revealed not only the classical marginal bodies but also the initial Anaplasma bodies in the erythrocytes of acutely infected animals. Singly occurring initial bodies were observed in the erythrocytes of healthy carriers.

The actomyosin protein complex of Physarum polycephalum was prepared from vegetative and starved plasmodia. The yield of actomyosin per unit wet wt. was the same from both types of plasmodia. Myosin was resolved from the complex by gel filtration and purified by ion-exchange chromatography. The Ca(2+)-stimulated adenosine triphosphatase activities of myosin preparations from vegetative and starved plasmodia were not appreciably different. Synthesis of myosin de novo was shown to occur during the starvation phase of the life-cycle by the isolation of labelled myosin preparations from plasmodia starved in the presence of [2-(14)C]glycine. Fractionation of polyacrylamide gels after gel filtration of labelled myosin confirmed the presence of label in the adenosine triphosphatase-active myosin band. It is concluded that during starvation myosin synthesis continues although there is a net loss of approx. 50% of the total protein. Sodium dodecyl sulphate-polyacrylamide-gel electrophoresis of Physarum myosin showed the presence of low-molecular-weight components of the molecule, similar to those of muscle myosins. The content and composition of the free amino acid pool of Physarum was measured at various time-intervals during the vegetative and starvation phases of the life-cycle.

A macroscopic plate test was found to be reliable and convenient for detection of Leptospira serotype pomona antibodies in bovine sera. However, the procedure was unreliable for detecting L. serotype canicola antibodies because of false positive reactions. An indirect immunofluorescence test and the microscopic agglutination test provided comparable results and they effectively detected serotype pomona antibodies in bovine sera.