Colicine K. IV. The effect of metabolites upon colicine synthesis.

The synthesis of colicine K by the colicinogenic bacillus E. coli K(235) has been studied in the chemostat. It has been found that colicine production is influenced by the pH of the medium, by the nature of the primary carbon source, and by the generation time of the microorganism.

Colicine K. III. The immunological properties of a substance having colicine K activity.

By immunological means it has been shown that colicine K is associated with the O antigen of the colicinogenic bacillus E. coli K(235) L(+)OC(+). The colicine K-O antigen complex elicits the formation of at least two types of antibodies, one a precipitin, the other a colicine-neutralizing antibody.

Colicine K. II. The preparation and properties of a substance having colicine K activity.

By chemical fractionation a substance having colicine K activity has been obtained from the culture medium of E. coli K(235) L(+)O. Colicine K activity was found associated with the O antigen of this microorganism.

Colicine K. I. The production of colicine K in media maintained at constant pH.

An apparatus for maintaining the pH of an actively growing bacterial culture at constant level has been described. Using this apparatus it has been shown that the production of maximal amounts of colicine K from a strain of E. coli known as K235 is dependent upon an enriched nutrient medium which is maintained at pH 7.

Lysis of T4 phage by the specific lipocarbohydrate of phase II Shigella sonnei.

When the specific lipocarbohydrate of Phase II Sh. sonnei and T(4) phage react in vitro, the virus is rapidly inactivated and the content of the viral membrane is released into the surrounding medium. The reaction between phage and lipocarbohydrate proceeds only in the presence of a lipide constituent which can be extracted from the polysaccharide, rendering the latter inactive, and which can be replaced by certain fatty acids.

The nature of prophage in lysogenic Bacillus megatherium.

1. By complement-fixation tests it has been shown that the lysogenic and sensitive strains of B. megatherium share one or more antigenic components which are serologically related but not identical.

The chemical and antiviral properties of the somatic antigen of Phase II Shigella sonnei.

1. The somatic antigen of Phase II Shigella sonnei can be isolated by extracting phenol-killed microorganisms with water. This substance inactivates all T phages to which this bacillus is susceptible.

The effect of chemical and physical agents on the phage receptor of Phase II Shigella sonnei.

A study has been made of the effect of bactericidal agents on the phage adsorption properties of Phase II. Sh. sonnei.

Studies on bacteriophage. II. Inhibition of lysis of Escherichia coli B by the somatic antigen of Phase II Shigella sonnei.

By serological means it has been shown that E. coli B contains an antigen closely related to the protein-lipocarbohydrate complex of Phase II Sh. sonnei.

On the nature of the toxic component of the somatic antigen of Shigella paradysenteriae type Z (Flexner).

From the chemical evidence presented it appears that the toxicity associated with the somatic antigen of Type Z Sh. paradysenteriae may be attributed to an entity distinct from the known components of the complex. That this substance is neither the protein, the lipid, nor the carbohydrate component of the antigen is evident.

Studies on bacteriophage; the relationship between the somatic antigens of Shigella sonnei and their susceptibilitv to bacterial viruses.

Phase I and Phase II Sh. sonnei exhibit differences in their susceptibility to the T series of bacteriophages. Both microorganisms are lysed by T(2) and T(6), but only the Phase II bacillus is lysed by T(3), T(4), and T(7).

Crystalline pneumococcus antibody.

1. The immune precipitate formed by antipneumococcus horse serum and the specific polysaccharide is not hydrolyzed by trypsin as is the diphtheria toxin-antitoxin complex, and purified pneumococcus antibody cannot be isolated by the method used for the isolation and crystallization of diphtheria antitoxin. 2.

The effect of lithium periodate on crystalline bovine serum albumin.

A study of the chemical, physicochemical, and immunological changes in bovine serum albumin, brought about by oxidation with lithium periodate, has been made. It has been shown that destruction of certain amino acids occurs, that a change in the absorption spectrum takes place, and that the electrophoretic behavior of the protein is altered. Prolonged contact of bovine albumin with lithium periodate destroys its ability to incite antibodies in experimental animals.

The specific antigens of variants of Shigella sonnei.

It has been shown that phase variation of Sh. sonnei is accompanied by changes in morphology and antigenic structure. Two mutants of the Phase I organism (II(S) and II(R)), which were studied, elaborate somatic antigens which are immunologically identical.

The inactivation of biologically active proteins, and the virus of western equine encephalomyelitis by periodic acid.

The action of periodic acid on two biologically active proteins, crystalline ribonuclease and pneumococcus Type III immune globulin, and on the virus of Western equine encephalomyelitis has been studied. The biological activity of the two proteins and the pathogenic action of the virus were destroyed by the reagent; the specific antigenicity of the immune globulin was retained, however, but that of the equine virus was lost. The bearing of these reactions on the chemical alteration of the respective substances has been discussed.

The effect of polysaccharides on the reaction between erythrocytes and viruses, with particular reference to mumps virus.

Polysaccharides which cause inhibition of the multiplication of mumps virus in the allantoic sac may or may not cause inhibition of hemagglutination by the virus. Moreover, such substances may or may not prevent adsorption of the virus by erythrocytes. The available evidence indicates that polysaccharides active as inhibitors do not block adsorption of mumps virus by cells of the living allantoic membrane.

The inhibitory effect of polysaccharide on mumps virus multiplication.

Polysaccharides derived from type-specific Friedländer bacilli cause inhibition of the multiplication of mumps virus in the allantoic sac of the chick embryo. As little as 5 microg. of polysaccharide is effective as an inhibitor.