| Title | Aglaophenia octodonta (Cnidaria, Hydrozoa) and the Associated Microbial Community: a Cooperative Alliance? |
| Abstract | Recently, genetic approaches have revealed a surprising bacterial world as well as a growing knowledge of the enormous distribution of animal-bacterial interactions. In the present study, the diversity of the microorganisms associated to the hydroid Aglaophenia octodonta was studied with epifluorescence, optical, and scanning electron microscopy. Small subunit ribosomal RNA gene sequencing with "universal" and taxon-specific primers allowed the assignment of the microalgae to Symbiodinium and the peritrich ciliates to Pseudovorticella, while the luminous vibrios were identified as Vibrio jasicida of the Harvey clade. To understand the possible relationships among Vibrio jasicida, Symbiodinium, A. octodonta, and Pseudovorticella, specific treatments were conducted in microcosm experiments, with the antibiotic ampicillin and other substances that interfere with bacterial and hydroid metabolism. Treatment of A. octodonta with ampicillin resulted in a decrease of bacterial luminescence followed by Pseudovorticella detachment and Symbiodinium expulsion and suggesting that these microorganisms form a "consortium" with beneficial metabolic interdependence. This hypothesis was reinforced by the evidence that low concentrations of hydrogen peroxide, which stimulate the bacterial oxidative metabolism and luminescence by releasing oxygen, were able to counteract the detrimental effect of ampicillin on the stability of the studied A. octodonta association. A model is proposed in which microalgae that release oxygen during photosynthesis are useful to luminous bacteria for their metabolism and for establishing/maintaining symbiosis leading to a close alliance and mutual benefit of the system A. octodonta-Vibrio jasicida-Pseudovorticella sp.-Symbiodinium sp. |
| Source | Microbial ecology 76 (1), pp. 258–271 |
| Keywords | FluorescenceHydrozoaLuminous bacteriaMicroalgaePeritrich ciliatesConsortium |
| Journal | Microbial ecology |
| Editor | Springer-Verlag,, New York,, Stati Uniti d'America |
| Year | 2018 |
| Type | Articolo in rivista |
| DOI | 10.1007/s00248-017-1127-3 |
| Authors | Stabili, Loredana; Gravili, Cinzia; Pizzolante, Graziano; Lezzi, Marco; Tredici, Salvatore Maurizio; De Stefano, Mario; Boero, Ferdinando; Alifano, Pietro |
| Text | 400025 2018 10.1007/s00248 017 1127 3 ISI Web of Science WOS 000437836200024 Fluorescence Hydrozoa Luminous bacteria Microalgae Peritrich ciliates Consortium Aglaophenia octodonta Cnidaria, Hydrozoa and the Associated Microbial Community a Cooperative Alliance Stabili, Loredana; Gravili, Cinzia; Pizzolante, Graziano; Lezzi, Marco; Tredici, Salvatore Maurizio; De Stefano, Mario; Boero, Ferdinando; Alifano, Pietro Univ Salento; UOS Taranto CNR; II Univ Naples; CNR ISMAR Recently, genetic approaches have revealed a surprising bacterial world as well as a growing knowledge of the enormous distribution of animal bacterial interactions. In the present study, the diversity of the microorganisms associated to the hydroid Aglaophenia octodonta was studied with epifluorescence, optical, and scanning electron microscopy. Small subunit ribosomal RNA gene sequencing with universal and taxon specific primers allowed the assignment of the microalgae to Symbiodinium and the peritrich ciliates to Pseudovorticella, while the luminous vibrios were identified as Vibrio jasicida of the Harvey clade. To understand the possible relationships among Vibrio jasicida, Symbiodinium, A. octodonta, and Pseudovorticella, specific treatments were conducted in microcosm experiments, with the antibiotic ampicillin and other substances that interfere with bacterial and hydroid metabolism. Treatment of A. octodonta with ampicillin resulted in a decrease of bacterial luminescence followed by Pseudovorticella detachment and Symbiodinium expulsion and suggesting that these microorganisms form a consortium with beneficial metabolic interdependence. This hypothesis was reinforced by the evidence that low concentrations of hydrogen peroxide, which stimulate the bacterial oxidative metabolism and luminescence by releasing oxygen, were able to counteract the detrimental effect of ampicillin on the stability of the studied A. octodonta association. A model is proposed in which microalgae that release oxygen during photosynthesis are useful to luminous bacteria for their metabolism and for establishing/maintaining symbiosis leading to a close alliance and mutual benefit of the system A. octodonta Vibrio jasicida Pseudovorticella sp. Symbiodinium sp. 76 Published version Articolo in rivista Springer Verlag, 0095 3628 Microbial ecology Microbial ecology Microb Ecol Microbial ecology. ferdinandoboero BOERO FERDINANDO loredana.stabili STABILI LOREDANA |
