The vast bacteriophage population harbors an immense reservoir of genetic information. Almost 2000 phage genomes have been sequenced from phages infecting hosts in the phylum Actinobacteria, and analysis of these genomes reveals substantial diversity, pervasive mosaicism, and novel mechanisms for phage replication and lysogeny. Here, we describe the isolation and genomic characterization of 46 phages from environmental samples at various geographic locations in the U.S. infecting a single Arthrobacter sp. strain. These phages include representatives of all three virion morphologies, and Jasmine is the first sequenced podovirus of an actinobacterial host. The phages also span considerable sequence diversity, and can be grouped into 10 clusters according to their nucleotide diversity, and two singletons each with no close relatives. However, the clusters/singletons appear to be genomically well separated from each other, and relatively few genes are shared between clusters. Genome size varies from among the smallest of siphoviral phages (15,319 bp) to over 70 kbp, and G+C contents range from 45–68%, compared to 63.4% for the host genome. Although temperate phages are common among other actinobacterial hosts, these Arthrobacter phages are primarily lytic, and only the singleton Galaxy is likely temperate.

Orcokinin neuropeptides are conserved among ecdysozoans, but their functions are incompletely understood. Here, we report a role for orcokinin neuropeptides in the regulation of sleep in the nematode Caenorhabditis elegans. The C. elegans orcokinin peptides, which are encoded by the nlp-14 and nlp-15 genes, are necessary and sufficient for quiescent behaviors during developmentally timed sleep (DTS) as well as during stress-induced sleep (SIS). The five orcokinin neuropeptides encoded by nlp-14 have distinct but overlapping functions in the regulation of movement and defecation quiescence during SIS. We suggest that orcokinins may regulate behavioral components of sleep-like states in nematodes and other ecdysozoans.

Caenorhabditis elegans displays two distinct sleep states: Developmentally timed sleep (DTS), which occurs during a life stage called lethargus (Raizen et al., 2008) and stress induced sleep (SIS), which occurs following exposure to environmental stress that damages cells. Both sleep states have been shown to be regulated by distinct neuropeptide signaling pathways. We have identified a new neuropeptide pathway that regulates SIS, neuropeptide‐like protein‐14 (NLP‐14). NLP‐14 shares sequence similarities (~69%) with a class of neuropeptides in arthropods called orcokinins (Nathoo et al., 2001), which are highly conserved within Ecdysozoans. In cockroaches, injection of exogenous orcokinin into the accessory medulla, a circadian pacemaker in the brain, results in a circadian phase shift (Hofer and Homberg, 2006). Interestingly, we have found that ectopic over‐expression of nlp‐14 during adulthood induces behavioral quiescence which resembles sleep. Specifically, when nlp‐14 over‐expression is induced under the control of a heat shock promoter, animals become quiescent for locomotion and show prolonged defecation cycles. Additionally, we find that nlp‐14(tm1880) reduction in function mutants display decreased SIS phenotype. Introduction of NLP‐14:GFP transgenes into this background rescues the SIS defects. The tm1880 allele eliminates 7 of the 12 encoded peptides in the NLP‐14 protein, leaving 5 peptides (NLP‐14‐2(2), NLP‐14‐4(2) and NLP‐14‐5(2)). We are currently attempting to remove the remaining peptides one at a time using the CRISPR‐cas9 system.Support or Funding InformationJohn P. McNulty Scholars ProgramThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.