title: Bacterial Community and PHB-Accumulating Bacteria Associated with the Wall and Specialized Niches of the Hindgut of the Forest Cockchafer (Melolontha hippocastani).
abstract: A characterization of the bacterial community of the hindgut wall of two larval and the adult stages of the forest cockchafer (Melolontha hippocastani) was carried out using amplicon sequencing of the 16S rRNA gene fragment. We found that, in second-instar larvae, Caulobacteraceae and Pseudomonadaceae showed the highest relative abundances, while in third-instar larvae, the dominant families were Porphyromonadaceae and Bacteroidales-related. In adults, an increase of the relative abundance of Bacteroidetes, Proteobacteria (γ- and δ- classes) and the family Enterococcaceae (Firmicutes) was observed. This suggests that the composition of the hindgut wall community may depend on the insect's life stage. Additionally, specialized bacterial niches hitherto very poorly described in the literature were spotted at both sides of the distal part of the hindgut chamber. We named these structures "pockets." Amplicon sequencing of the 16S rRNA gene fragment revealed that the pockets contained a different bacterial community than the surrounding hindgut wall, dominated by Alcaligenaceae and Micrococcaceae-related families. Poly-β-hydroxybutyrate (PHB) accumulation in the pocket was suggested in isolatedAchromobactersp. by Nile Blue staining, and confirmed by gas chromatography-mass spectrometry analysis (GC-MS) on cultured bacterial mass and whole pocket tissue. Raman micro-spectroscopy allowed to visualize the spatial distribution of PHB accumulating bacteria within the pocket tissue. The presence of this polymer might play a role in the colonization of these specialized niches.
authors.affiliation: Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology Jena, Germany.
authors.forename: Pol
authors.initials: P
authors.lastname: Alonso-Pernas
authors.affiliation: Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology Jena, Germany.
authors.forename: Erika
authors.initials: E
authors.lastname: Arias-Cordero
authors.affiliation: Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology Jena, Germany.
authors.forename: Alexey
authors.initials: A
authors.lastname: Novoselov
authors.affiliation: Center for Sepsis Control and Care, Jena University HospitalJena, Germany; Leibniz Institute of Photonic TechnologyJena, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Ebert
authors.affiliation: Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology Jena, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Rybak
authors.affiliation: Department of Evolutionary Ecology, Institute of Zoology, Johannes Gutenberg University Mainz Mainz, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Kaltenpoth
authors.affiliation: Electron Microscopy Center, Jena University Hospital Jena, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Westermann
authors.affiliation: Center for Sepsis Control and Care, Jena University HospitalJena, Germany; Leibniz Institute of Photonic TechnologyJena, Germany.
authors.forename: Ute
authors.initials: U
authors.lastname: Neugebauer
authors.affiliation: Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology Jena, Germany.
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Boland
keywords: Achromobacter; Melolontha hippocastani; PHB; Raman microscopy; gut bacteria; hindgut; poly-β-hydroxybutyrate