Using the filter paper disk diffusion assay technique as a tool in our antibiotic screening program, occasional samples have been encountered that were without inhibitory activity but induced a marked stimulation of the test organism, Bacillus subtilis, ATCC 6633. This effect was manifested as a zone of heavy growth in the region of the plate surrounding the disk saturated with the sample under test and was sharply demarcated from a less dense background. Low power microscopic examination of the area revealed larger surface colonies in the stimulated area. Within this stimulated zone, occasional subsurface colonies could be seen that were comparable in size with the smaller colonies in the area outside the stimulated zone, suggesting that stimulation of growth occurred only under conditions of strict aerobiosis. When an extract of Streptomyces sp mycelium became available that consistently produced the effect, an attempt was made to isolate the stimulatory factor. It was found that an acid extract of the ash of the sample contained the active principle. Tests with various inorganic ions revealed that manganese salts SUMMARY Manganese has been shown to stimulate sporulation of several species of the genus Bacillus. Sporulation is specifically dependent upon the presence of manganese at a concentration greater than that required for full vegetative growth of BaciUus subtilis, ATCC 6633, which was studied further as a representative of the genus.
Several antigen display platforms are being explored to optimize the immune response. While various viruses have been studied as antigen delivery tools, the tomato bushy stunt virus (TBSV) has great potential for use as a platform due to its symmetrical structure that enhances epitope display. 180 identical subunits form a single TBSV particle that can prominently display multiple copies of an epitope. TBSV's high antigen density makes it a highly efficient means of ensuring epitope recognition, thereby increasing antibody response. TBSV is especially useful because the C‐terminus sites of its capsid protein are clearly exposed. This structure allows epitopes to be added and to maintain their original tertiary structure when bound to the viral capsid. The TBSV platform was tested by addition of modified ricin toxin to the capsid protein C‐terminus. Mice injected with the construct had increased antibody responses, indicating that the high antigen density created by modified TBSV led to increased immune response. The Canyon Crest Academy SMART Team (Students Modeling A Research Topic) modeled TBSV using 3D printing technology. This 3D model allows for more thorough analysis of TBSV's structure and fuller understanding of the characteristics that make it an attractive platform for vaccine design. Supported by a grant from the HHMI Pre‐College Program.
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