bioRxiv Science⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/283937

Bacillus safensis FO-36b and Bacillus pumilus SAFR-032: A Whole Genome Comparison of Two Spacecraft Assembly Facility Isolates

Tirumalai, M.·Stepanov, V. G.·Wunsche, A.·Montazari, S.·Gonzalez, R. O.·Venkateswaran, K.·Fox, G. E.
View original source ↗Export metadata ↓

Abstract

BackgroundBacillus strains producing highly resistant spores have been isolated from cleanrooms and space craft assembly facilities. Organisms that can survive such conditions merit planetary protection concern and if that resistance can be transferred to other organisms, a health concern too. To further efforts to understand these resistances, the complete genome of Bacillus safensis strain FO-36b, which produces spore resistant to peroxide and radiation was determined. The genome was compared to the complete genome of B. pumilus SAFR-032, as well as draft genomes of B. safensis JPL-MERTA-8-2 and the type strain B. pumilus ATCC7061T. In addition, comparisons were made to 61 draft genomes that have been mostly identified as strains of B. pumilus or B. safensis.\n\nResultsThe FO-36b gene order is essentially the same as that in SAFR-032 and other B. pumilus strains [1]. The annotated genome has 3850 open reading frames and 40 noncoding RNAs and riboswitches. Of these, 307 are not shared by SAFR-032, and 65 are also not shared by either MERTA or ATCC7061T. The FO-36b genome was found to have ten unique reading frames and two phage-like regions, which have homology with the Bacillus bacteriophage SPP1 (NC_004166) and Brevibacillus phage Jimmer1 (NC_029104). Differing remnants of the Jimmer1 phage are found in essentially all safensis/pumilus strains. Seven unique genes are part of these phage elements. Comparison of gyrA sequences from FO-36b, SAFR-032, ATCC7061T, and 61 other draft genomes separate the various strains into three distinct clusters. Two of these are subgroups of B. pumilus while the other houses all the B. safensis strains.\n\nConclusionsIt is not immediately obvious that the presence or absence of any specific gene or combination of genes is responsible for the variations in resistance seen. It is quite possible that distinctions in gene regulation can change the level of expression of key proteins thereby changing the organisms resistance properties without gain or loss of a particular gene. What is clear is that phage elements contribute significantly to genome variability. The larger comparison of multiple strains indicates that many strains named as B. pumilus actually belong to the B. safensis group.

Source connections

Explore related subjects

genomicsPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Tirumalai, M., Stepanov, V. G., Wunsche, A., Montazari, S., Gonzalez, R. O., Venkateswaran, K., Fox, G. E.. 2018-03-16. Bacillus safensis FO-36b and Bacillus pumilus SAFR-032: A Whole Genome Comparison of Two Spacecraft Assembly Facility Isolates. https://doi.org/10.1101/283937

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Recurrent mitotic error and purifying selection shape chromosomal mosaicism across human tissues

Mosaic chromosomal alterations (mCAs) have been extensively studied in cancer and clonal hematopoiesis but less so in healthy solid tissues. Here, we characterized mCAs in 19 tissues across 25 donors (aged 42-89+ years) by analyzing >200x whole-genome sequencing data generated by the Somatic Mosaicism across Human Tissues (SMaHT) Network. Across 722 tissue samples, we identified 1,008 autosomal mCAs >1 Mb in length and ubiquitous losses of sex chromosomes. Surprisingly, the highest levels of Y chromosome loss in males (5-10% cell fraction in elderly donors) were observed in the lung, adrenal gland, and heart. These tissues also tended to experience more X loss in females, revealing a gradient of mitotic error burden across human tissues. Autosomal aneuploidies displayed distinct tissue-specific patterns indicative of negative selection against most events, except in the adrenal gland, in which low-level aneuploidy was pervasive. In contrast to the adrenal gland, testis rarely harbored aneuploidies but frequently experienced low-level copy-neutral loss of heterozygosity (CN-LOH), suggesting increased mitotic recombination in spermatogonial stem cells. Recurrent X chromosome losses within tissues of female donors exhibited allelic skews explained by a combination of genetic and epigenetic effects. Together, these results show that the chromosomal landscape of aging human tissues is shaped by genetics and recurrent mutations, most but not all of which are held in check by purifying selection.

genomics↗
bioRxiv2026

Multi-modal in situ profiling of human cells using the AVITI24 platform characterizes single-cell responses to acute stress

Cells begin to respond to stress within minutes, but how this early response depends on cell type, neighboring cells, or cell cycle phase has been difficult to determine, because bulk assays average across cells and synchronization can induce stress. We measured 338 transcripts, 48 proteins and phosphoproteins, and six cell paint stains in situ in 1.18 million single cells from four human cell lines exposed to H2O2, alone and in co-culture, and in A549 cells exposed to TNF-, cadmium, dithiothreitol or lipopolysaccharide. In A549 cells, five distinct stressors changed the same targets in the same direction within 15 min, differing mainly in magnitude, and modestly increased JNK phosphorylation. By 30 min of H2O2 treatment, immediate-early genes (FOS, JUN, DDIT3, DUSP1, NR4A1) were induced most strongly in HCT116 and A549 cells. These changes occurred across the whole cell population rather than in a responsive subset. Cell line-specific differences persisted in co-culture, and the response of MCF7 cells did not increase with the number of adjacent, strongly-responding A549 cells. Ordering cells along the cell cycle from the same measurements identified 106 cycle-associated transcripts, and the response varied more between cell lines than among cell cycle phases. Overall, the measured regulators respond to stress within 30 minutes through a largely shared program whose magnitude depends more on cell identity than on cell cycle state or neighboring cell type.

genomics↗
bioRxiv2026

A Chromosome Scale Genome Assembly for the Australian blue mussel Mytilus planulatus

Mussels belonging to the genus Mytilus are among the world's most ecologically and economically important bivalve molluscs. Although the genus most likely originated in the Northern Hemisphere, the evolutionary history of Southern Hemisphere lineages, including the timing and number of colonisation events leading to the extant Australian populations, remains debated. Limited genomic resources have hindered the reconstruction of these evolutionary histories. In Australia, distinguishing native Mytilus planulatus from invasive Mytilus galloprovincialis is critical for biosecurity and conservation, but previous molecular approaches lacked sufficient resolution to resolve species boundaries and hybridisation patterns. Here, we present the first chromosome-scale reference genome for M. planulatus. The assembly consists of 14 chromosomes and over 51,000 annotated protein-coding genes per haplotype. Comparative analysis revealed extensive structural variation and widespread hemizygosity despite a largely conserved chromosomal organisation relative to M. galloprovincialis. Population analyses using SNPs and gene presence-absence variation in resequenced individuals confirmed previously inferred patterns of population structure and establish this reference genome as a valuable resource for future studies of genome evolution, adaptation and population genomics in Mytilus.

genomics↗