RESUMO
Pigmented bacterial symbionts play major roles in the health of coral holobionts. However, there is scarce knowledge on the diversity of these microbes for several coral species. To gain further insights into holobiont health, pigmented bacterial isolates of Fabibacter pacificus (Bacteroidetes; n = 4), Paracoccus marcusii (Alphaproteobacteria; n = 1), and Pseudoalteromonas shioyasakiensis (Gammaproteobacteria; n = 1) were obtained from the corals Mussismilia braziliensis and Montastraea cavernosa in Abrolhos Bank, Brazil. Cultures of these bacterial symbionts produced strong antioxidant activity (catalase, peroxidase, and oxidase). To explore these bacterial isolates further, we identified their major pigments by HPLC and mass spectrometry. The six phylogenetically diverse symbionts had similar pigment patterns and produced myxol and keto-carotene. In addition, similar carotenoid gene clusters were confirmed in the whole genome sequences of these symbionts, which reinforce their antioxidant potential. This study highlights the possible roles of bacterial symbionts in Montastraea and Mussismilia holobionts.
Assuntos
Antozoários/microbiologia , Antioxidantes/metabolismo , Bacteroidetes/metabolismo , Paracoccus/metabolismo , Pigmentos Biológicos/metabolismo , Pseudoalteromonas/metabolismo , Animais , Bacteroidetes/genética , Bacteroidetes/isolamento & purificação , Brasil , Carotenoides/metabolismo , Catalase/biossíntese , DNA Bacteriano/genética , Genoma Bacteriano/genética , Oxirredutases/biossíntese , Paracoccus/genética , Paracoccus/isolamento & purificação , Peroxidase/biossíntese , Pigmentos Biológicos/genética , Pseudoalteromonas/genética , Pseudoalteromonas/isolamento & purificação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , SimbioseRESUMO
An orange-pigmented, oxidase-positive bacterial strain (I-41R45T), isolated from the kidney of a black rock cod fish sampled in the Chilean Antarctic was studied in a polyphasic taxonomic investigation. Cells of the isolate were coccoid and stained Gram-negative. A comparison of the 16S rRNA gene sequence of strain I-41R45T with sequences of type strains of most closely related Paracoccus species showed highest sequence similarities to Paracoccus hibiscisoli (98.4â%), Paracoccus marcusii (98.3â%), Paracoccus haeundaensis and Paracoccus carotinifaciens (both 98.2â%). 16S rRNA gene sequence similarities to all other Paracoccus species were below 97â%. The draft genome of strain I-41R45T had a size of 4.59 Mb with a DNA G+C content of 65.26 mol% and included the prediction and annotation of 4426 coding genes, 1973 protein-coding genes and 46 tRNAs. The fatty acid profile of strain I-41R45T consisted mainly of the major fatty acids C18â:â1 ω7c/ω9t/ω12t and C18:0, typical of the genus Paracoccus. DNA-DNA hybridizations between I-41R45T and type strains of P. hibiscisoli, P. marcusiiand P. haeundaensis resulted in similarity values of 45â% (reciprocal 26â%), 66â% (reciprocal 61â%), and 29â% (reciprocal 36â%), respectively. DNA-DNA hybridization results, together with the differentiating biochemical and chemotaxonomic properties, showed that strain I-41R45T represents a novel Paracoccus species, for which the name Paracoccus nototheniae sp. nov. (type strain I-41R45T=CCM 8875T=CIP 111632T), is proposed.
Assuntos
Rim/microbiologia , Paracoccus/classificação , Perciformes/microbiologia , Filogenia , Animais , Regiões Antárticas , Técnicas de Tipagem Bacteriana , Composição de Bases , Chile , DNA Bacteriano/genética , Ácidos Graxos/química , Hibridização de Ácido Nucleico , Paracoccus/isolamento & purificação , Pigmentação , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
A horizontal-flow anaerobic immobilized biomass reactor (HAIB) containing denitrifying biomass was evaluated with respect to its ability to remove, separately and in a short operating period (30 days), organic matter, nitrate, and the hydrocarbons benzene (41.4 mg L-1), toluene (27.8 mg L-1), ethylbenzene (31.1 mg L-1), o-xylene (28.5 mg L-1), m-xylene (28.4 mg L-1) and p-xylene (32.1 mg L-1). The purified culture, which was grown in the presence of the specific hydrocarbon, was used as the source of cells to be immobilized in the polyurethane foam. After 30 days of operation, the foam was removed and a new immobilized biomass was grown in the presence of another hydrocarbon. The average hydrocarbon removal efficiency attained was 97%. The organic matter, especially ethanol, was removed with an average efficiency of 83% at a mean influent concentration of 1185.0 mg L-1. A concomitant removal of 97% of nitrate was observed for a mean influent concentration of 423.4 mg L-1. The independent removal of each hydrocarbon demonstrated that these contaminants can be biodegraded separately, without the need for a compound to be the primary substrate for the degradation of another. This study proposes the application of the system for treatment of areas contaminated with these compounds, with substitution and formation of a biofilm in a 30-day period.