Specificity of the Induced Bactericidin of the West Indian Spiny Lobster, Panulirus argus

To investigate the specificity of an inducible hemolymph bactericidin, West Indian spiny lobsters were immunized with a variety of antigens. Bactericidal assays were conducted with strain EMB-1, a gram-negative bacillus isolated from normal lobster intestine. Animals given saline solution with or without 0.3% Formalin exhibited only a slight response similar to sham controls. Injections of type 2 pneumococci or bovine albumin produced slightly higher responses. These were much less pronounced than the homologous response to EMB-1. Formalin exhibited an adjuvant-like effect with EMB-1.     

The stoicheiometry of electron transfer by bacterial and plant ferredoxins

1. The number of electrons carried by ferredoxins from spinach, the blue-green alga Anacystis nidulans, the anaerobic bacterium Clostridium welchii and the photosynthetic bacterium Chromatium was determined. 2. Ferredoxins were reduced by illuminated chloroplasts, and the stoicheiometry of the reoxidation in the dark of the ferredoxins by NADP and benzyl viologen was measured. 3. Spinach and A. nidulans ferredoxins were found to be one-electron carriers, and Cl. welchii and Chromatium ferredoxins were two-electron carriers.     

Effects of various compounds on growth of yeast cells of Histoplasma capsulatum

Summary A number of compounds were screened for their effects on growth of the yeast cells ofHistoplasma capsulatum. Included were penicillin and related compounds, sulfhydryl inhibitors, various organic sulfur compounds recently synthesized for the first time, and compounds structurally related to the required metabolites, thiamine and cystine or cysteine. Cephalothin was the only one of the penicillin related compounds which inhibited growth. This occurred only when a high concentration (8.3 × 10^–4 M) was used. Of the analogues of cystine tested, allylglycine had the greatest inhibitory effect on growth of the yeast cells in the synthetic medium, but it failed to inhibit growth in a complex medium containing peptones and plasma. Among the sulfhydryl inhibitors, the maleimides were the most effective, producing complete inhibition of growth in the peptone medium at 10µg/ml or less. At subinhibitory concentrations the cultures tended to become mycelial. The action of the maleimides was reversed by cystine over a range of concentrations. At low concentrations, some of the disulfide derivatives of thiamine stimulated growth equally as well as thiamine, but at concentrations of 100 to 150µg/ml, they completely inhibited growth. On the basis of results obtained to date, three classes of the new organic sulfur compounds being tested offer promise as sources of potentially useful chemotherapeutic agents. These classes, which differ widely in structure, are as follows: the benzyl decylaminoethyl disulfides, the acyl disulfides, and the trithiopercarbamates.This investigation was supported by Public Health Service Research Grant AI-03524 from the National Institute of Allergy and Infectious Diseases.