Learn More
Prelaunch planetary protection protocols on spacecraft are designed to reduce the numbers and diversity of viable bioloads on surfaces in order to mitigate the forward contamination of planetary surfaces. In addition, there is a growing appreciation that prelaunch spacecraft cleaning protocols will be required to reduce the levels of biogenic signature(More)
As part of an ongoing effort to catalog spore-forming bacterial populations in environments conducive to interplanetary transfer by natural impacts or by human spaceflight activities, spores of Bacillus spp. were isolated and characterized from the interior of near-subsurface granite rock collected from the Santa Catalina Mountains, AZ. Granite was found to(More)
Translational lacZ fusions to forespore genes of Bacillus subtilis were not expressed in spoIIAC (sigma F) or spoIIIE mutants when the lacZ fusions were integrated at the loci of the same genes or at the SP beta locus. However, some of these genes, including gerA, gpr, spoIIIG (sigma G), and sspE, were expressed in spoIIIE mutants and spoIIIE spoIIIG double(More)
In terms of resistance to extreme environmental stresses, the bacterial spore represents a pinnacle of evolution. Spores are highly resistant to a wide variety of physical stresses such as: wet and dry heat, UV and gamma radiation, oxidizing agents, chemicals, and extremes of both vacuum and ultrahigh hydrostatic pressure. Some of the molecular mechanisms(More)
Upon UV irradiation, Bacillus subtilis spore DNA accumulates the novel thymine dimer 5-thyminyl-5,6-dihydrothymine. Spores can repair this "spore photoproduct" (SP) upon germination either by the uvr-mediated general excision repair pathway or by the SP-specific spl pathway, which involves in situ monomerization of SP to two thymines by an enzyme named SP(More)
The sspB and sspE genes code for major small, acid-soluble proteins of Bacillus subtilis spores and are transcribed during sporulation by RNA polymerase containing sigma G. Analysis of the expression in vivo and the sigma G-dependent transcription in vitro of sspB and sspE genes carrying upstream deletions or point mutations in -10 and -35 promoter regions(More)
In response to UV irradiation, Bacillus subtilis spore DNA accumulates the unique thymine dimer 5-thyminyl-5,6-dihydrothymine, or spore photoproduct (SP). SP is broken down into monomers during spore germination by the product of the spl gene which has been proposed to encode the enzyme SP lyase. The wild-type spl gene was cloned by complementation of a(More)
Germinating Bacillus subtilis spores repair UV-induced DNA damage in part using the enzyme spore photoproduct (SP) lyase. SP lyase is encoded by splB, the second cistron of the splAB operon. The splAB operon is transcribed during sporulation from the P1 promoter, which partially overlaps the transcriptional terminator of the upstream ptsHI operon, which in(More)
UV resistance of bacterial endospores derives from a unique DNA photochemistry in which the major UV photoproduct is the thymine dimer 5-thyminyl-5,6-dihydrothymine (spore photoproduct [SP]) instead of cyclobutane pyrimidine dimers. Repair of SP during spore germination is due in large part to the activity of the enzyme SP lyase encoded by splB, the second(More)