Blood proteins, antibacterial activity

Genes Specifying Antibacterial Protein Structure. Adult flies and larvae of Drosophila and Ceratitis do not normally contain in their blood proteins that specifically kill bacteria. However, when animals are inoculated with Enterobacter cloacae, potent antibacterial activity appears in the blood (11,12,17,18). Antibacterial activity is detected in the blood of adult Drosophila melanogaster flies within two hours after inoculation, and is still detectable sixty days later (11). Investigation of this activity by isoelectric focusing reveals several blood proteins with antibacterial activity... 

Although the determination of the tissue levels gives important information about distribution of the sulfonamides in various organs (15), it furnishes no indication as to the local active concentration of the antibacterial. According to modem views, sulfonamides are bound reversibly to blood proteins, mostly the albumins. The degree of protein binding varies considerably among various... 

Although historically most useful antibiotics have come from spore forming microorganisms, marine organisms have yielded the candidate antitumor peptide didemnin B [77327-50-0] (2) and cytostatic peptides such as the patellamides (3). Many of the marine peptides have little or no antimicrobial activity. Antibacterial peptides called magainins are found in frog skin (4) and antibacterial proteins called defensins are found in mammalian white blood cells (5). The commercially important insecticidal proteins from Bacillus thuringensis (6) are not discussed herein nor are the numerous peptide siderophores (7,8), which, except for the albomycins (9), are usually not antimicrobial. 

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