Indoor surfaces are paradoxically presumed to be both colonized by pathogens, necessitating disinfection, and “microbial wastelands.” In these resource-poor, dry environments, competition and decay are thought to be important drivers of microbial community composition. However, the relative contributions of these two processes have not been specifically evaluated. To bridge this knowledge gap, we used microcosms to evaluate whether interspecies interactions occur on surfaces. We combined transcriptomics and traditional microbiology techniques to investigate whether competition occurred between two clinically important pathogens, Acinetobacter baumannii and Klebsiella pneumoniae, and a probiotic cleaner containing a consortium of Bacillus species. Probiotic cleaning seeks to take advantage of ecological principles such as competitive exclusion, thus using benign microorganisms to inhibit viable pathogens, but there is limited evidence that competitive exclusion in fact occurs in environments of interest (i.e., indoor surfaces). Our results indicate that competition in this setting has a negligible impact on community composition but may influence the functions expressed by active organisms. Although Bacillus spp. remained viable on surfaces for an extended period of time after application, viable colony forming units (CFUs) of A. baumannii recovered following exposure to a chemical-based detergent with and without Bacillus spp. showed no statistical difference. Similarly, for K. pneumoniae, there were small statistical differences in CFUs between cleaning scenarios with or without Bacillus spp. in the chemical-based detergent. The transcriptome of A. baumannii with and without Bacillus spp. exposure shared a high degree of similarity in overall gene expression, but the transcriptome of K. pneumoniae differed in overall gene expression, including reduced response in genes related to antimicrobial resistance. Together, these results highlight the need to fully understand the underlying biological and ecological mechanisms for community assembly and function on indoor surfaces, as well as having practical implications for cleaning and disinfection strategies for infection prevention.

Ascidians are invertebrate chordates with different modes of reproduction and solitary vs. colonial organization, as well as diverse genomes, morphological features, and regenerative capacities. The botryllid clade of ascidians are a growing model for coloniality, whole body regeneration, immune function, genome expansion, and the evolution of these traits. This study implements a hybrid assembly technique with cost-effective sequencing to produce a genome assembly and annotation for the botryllid ascidian, Botrylloides violaceus. A hybrid genome assembly was produced using Illumina, Inc. short and Oxford Nanopore Technologies long read sequencing technologies. The resulting assembly is comprised of 831 contigs, has a total length of 121 Mbp, N50 of 1 Mbp and a BUSCO score of 96.1\%. Genome annotation identified ~13,000 protein coding genes. Comparative genomic analysis with other tunicates reveals patterns of conservation and divergence within orthologous gene families even among closely related species. Characterization of the Wnt gene family, encoding signaling ligands involved in development and regeneration, reveals conserved patterns of subfamily presence and gene copy number among botryllids. We assembled and annotated the first genome for the colonial ascidian Botrylloides violaceus. This genome supports the use of economical genomic data from non-model organisms in the investigation of biological phenomena.

Colonial ascidians, or sea squirts, are invertebrate urochordates noted for their remarkable regenerative potential. One such organism, Botrylloides violaceus, is capable of undergoing whole body regeneration (WBR) from its peripheral vasculature. Studying the cellular mechanisms of regeneration in B. violaceus could provide insight into regenerative mechanisms in vertebrates. Specifically, since the Wnt signaling pathway has been consistently linked with regeneration in other organisms, we investigated its possible involvement in WBR for B. violaceus. Our results demonstrate that B. violaceus completed WBR an average of 4.5 days faster than control regenerates when treated with a Wnt agonist. This suggests that the Wnt pathway is involved in activating cellular signals that facilitate WBR in B. violaceus. We continue to investigate effects of other pharmacological manipulations of the Wnt pathway. We are also attempting to amplify possible Wnt homologs using PCR with degenerate primers derived from conserved Wnt sequences. Obtaining DNA sequence for B. violaceus Wnts will allow future experiments on Wnt gene expression during regeneration.Support or Funding InformationCalifornia Polytechnic State University, Biological Sciences Department; Frost Summer 2017 Undergraduate Research ProgramThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Modern genome sequencing technologies open new avenues for research on biological processes in non‐model organisms. Colonial ascidians are a diverse group of invertebrate chordates capable of whole body regeneration, an unusual trait that is absent from vertebrates. Although genomic data are available for a few related species, there exist no such data for the highly regenerative species Botrylloides violaceus. Using a de novo hybrid assembly approach, we present the first draft of the B. violaceus genome sequence. By integrating short read and long read sequencing technologies, genome assembly becomes cost‐effective and easily accessible. Comparative genomic analysis between B. violaceus and other chordate genomes reveals insights into the evolution of gene families implicated in regeneration and development. Support or Funding Information Warren J. Baker and Robert D. Koob Endowments, California Polytechnic State University; The Frost Fund, College of Science and Mathematics, California Polytechnic State University

Colonial ascidians are the closest known relatives to vertebrates that retain whole body regeneration. Understanding molecular pathways involved in regeneration in a diverse range of organisms will provide insights into evolutionary changes in regeneration. Specifically, our research explores Wnt signaling in the colonial ascidian Botrylloides violaceus; this highly conserved pathway is universally involved in studied animals with any regenerative ability. A recent rough draft genome for B. violaceus reveals multiple putative ligands, receptors, and downstream effectors from the Wnt pathway. Primers designed from the draft genome are being used in PCR to validate these predicted genes. Future studies will use qPCR to track gene expression of different Wnt pathway members through regeneration. Support or Funding Information The Frost Fund, College of Science and Mathematics at California Polytechnic State University, San Luis Obispo