title: Antimicrobial Activity of Actinobacteria Isolated From the Guts of Subterranean Termites.
abstract: Subterranean termites need to minimize potentially pathogenic and competitive fungi in their environment in order to maintain colony health. We examined the ability of Actinobacteria isolated from termite guts in suppressing microorganisms commonly encountered in a subterranean environment. Guts from two subterranean termite species, Reticulitermes flavipes (Kollar) and Reticulitermes tibialis Banks, were extracted and plated on selective chitin media. A total of 38 Actinobacteria isolates were selected for in vitro growth inhibition assays. Target microbes included three strains of Serratia marcescens Bizio, two mold fungi (Trichoderma sp. and Metarhizium sp.), a yeast fungus (Candida albicans (C.P. Robin) Berkhout), and four basidiomycete fungi (Gloeophyllum trabeum (Persoon) Murrill, Tyromyces palustris (Berkeley & M.A. Curtis) Murrill, Irpex lacteus (Fries) Fries, and Trametes versicolor (L.) Lloyd). Results showed both broad and narrow ranges of antimicrobial activity against the mold fungi, yeast fungus, and S. marcescens isolates by the Actinobacteria selected. This suggests that termite gut-associated Actinobacteria produce secondary antimicrobial compounds that may be important for pathogen inhibition in termites. Basidiomycete fungi were strongly inhibited by the selected Actinobacteria isolates, with G. trabeum and T. versicolor being most inhibited, followed by I. lacteus and T. palustris The degree of inhibition was correlated with shifts in pH caused by the Actinobacteria. Nearly all Actinobacteria isolates raised pH of the growth medium to basic levels (i.e. pH ∼8.0-9.5). We summarize antimicrobial activity of these termite gut-associated Actinobacteria and examine the implications of these pH shifts.
authors.affiliation: USDA Forest Products Laboratory, One Gifford Pinchot Dr., Madison, WI 53726 (rarango@fs.fed.us; fgreen@fs.fed.us) rarango@fs.fed.us.|Department of Entomology, University of Wisconsin-Madison, 1630 Linden Dr., Madison, WI 53706 (raffa@entomology.wisc.edu).
authors.forename: R A
authors.initials: RA
authors.lastname: Arango
authors.affiliation: Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Dr., Madison, WI 53706 (cmcarlson5@wisc.edu; currie@bact.wisc.edu; mcdonald.mcb@gmail.com; adamjbook@gmail.com).
authors.forename: C M
authors.initials: CM
authors.lastname: Carlson
authors.affiliation: Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Dr., Madison, WI 53706 (cmcarlson5@wisc.edu; currie@bact.wisc.edu; mcdonald.mcb@gmail.com; adamjbook@gmail.com).
authors.forename: C R
authors.initials: CR
authors.lastname: Currie
authors.affiliation: Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Dr., Madison, WI 53706 (cmcarlson5@wisc.edu; currie@bact.wisc.edu; mcdonald.mcb@gmail.com; adamjbook@gmail.com).
authors.forename: B R
authors.initials: BR
authors.lastname: McDonald
authors.affiliation: Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Dr., Madison, WI 53706 (cmcarlson5@wisc.edu; currie@bact.wisc.edu; mcdonald.mcb@gmail.com; adamjbook@gmail.com).
authors.forename: A J
authors.initials: AJ
authors.lastname: Book
authors.affiliation: USDA Forest Products Laboratory, One Gifford Pinchot Dr., Madison, WI 53726 (rarango@fs.fed.us; fgreen@fs.fed.us).
authors.forename: F
authors.initials: F
authors.lastname: Green
authors.affiliation: Department of Food Science, Washington State University, 100 Dairy Rd., Pullman, WA 99164 (noelle.lebow@wsu.edu).
authors.forename: N K
authors.initials: NK
authors.lastname: Lebow
authors.affiliation: Department of Entomology, University of Wisconsin-Madison, 1630 Linden Dr., Madison, WI 53706 (raffa@entomology.wisc.edu).
authors.forename: K F
authors.initials: KF
authors.lastname: Raffa
mesh_terms: D039903:Actinobacteria / Q000235:genetics / Q000502:physiology*; D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects; D005658:Fungi / Q000187:drug effects; D000069196:Gastrointestinal Microbiome / Q000187:drug effects; D020049:Isoptera / Q000382:microbiology*; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017423:Sequence Analysis, RNA
chemical_list: D000890:Anti-Infective Agents; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S
keywords: Reticulitermes spp.; Streptomyces spp.; basidiomycetes; mold fungi; pH