scholarly journals Metabolic complementarity between a brown alga and associated cultivable bacteria provide indications of beneficial interactions

2019 ◽  
Author(s):  
Bertille Burgunter-Delamare ◽  
Hetty KleinJan ◽  
Clémence Frioux ◽  
Enora Fremy ◽  
Margot Wagner ◽  
...  
Keyword(s):  
Brown Algae ◽  
Metabolic Networks ◽  
Algal Growth ◽  
Microbial Interactions ◽  
Associated Bacteria ◽  
Ectocarpus Siliculosus ◽  
Cultivable Bacteria ◽  
Algal Metabolism ◽  
Algal Host ◽  
Set Up

AbstractBrown algae are key components of marine ecosystems and live in association with bacteria that are essential for their growth and development. Ectocarpus siliculosus is a genetic and genomic model for brown algae. Here we use this model to start disentangling the complex interactions that may occur between the algal host and its associated bacteria. We report the genome-sequencing of 10 alga-associated bacteria and the genome-based reconstruction of their metabolic networks. The predicted metabolic capacities were then used to identify metabolic complementarities between the algal host and the bacteria, highlighting a range of potentially beneficial metabolite exchanges between them. These putative exchanges allowed us to predict consortia consisting of a subset of these ten bacteria that would best complement the algal metabolism. Finally, co-culture experiments were set up with a subset of these consortia to monitor algal growth as well as the presence of key algal metabolites. Although we did not fully control but only modify bacterial communities in our experiments, our data demonstrated a significant increase in algal growth in cultures inoculated with the selected consortia. In several cases, we also detected, in algal extracts, the presence of key metabolites predicted to become producible via an exchange of metabolites between the alga and the microbiome. Thus, although further methodological developments will be necessary to better control and understand microbial interactions in Ectocarpus, our data suggest that metabolic complementarity is a good indicator of beneficial metabolite exchanges in holobiont.

scholarly journals Genome–Scale Metabolic Networks Shed Light on the Carotenoid Biosynthesis Pathway in the Brown Algae Saccharina japonica and Cladosiphon okamuranus

Antioxidants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 564 ◽  
Author(s):  
Nègre ◽  
Aite ◽  
Belcour ◽  
Frioux ◽  
Brillet-Guéguen ◽  
...  
Keyword(s):  
Brown Algae ◽  
Metabolic Networks ◽  
Saccharina Japonica ◽  
Carotenoid Biosynthesis ◽  
Biosynthesis Pathway ◽  
Ectocarpus Siliculosus ◽  
Cladosiphon Okamuranus ◽  
Carotenoid Biosynthesis Pathway ◽  
The One ◽  
Genome Scale

Understanding growth mechanisms in brown algae is a current scientific and economic challenge that can benefit from the modeling of their metabolic networks. The sequencing of the genomes of Saccharina japonica and Cladosiphon okamuranus has provided the necessary data for the reconstruction of Genome–Scale Metabolic Networks (GSMNs). The same in silico method deployed for the GSMN reconstruction of Ectocarpus siliculosus to investigate the metabolic capabilities of these two algae, was used. Integrating metabolic profiling data from the literature, we provided functional GSMNs composed of an average of 2230 metabolites and 3370 reactions. Based on these GSMNs and previously published work, we propose a model for the biosynthetic pathways of the main carotenoids in these two algae. We highlight, on the one hand, the reactions and enzymes that have been preserved through evolution and, on the other hand, the specificities related to brown algae. Our data further indicate that, if abscisic acid is produced by Saccharina japonica, its biosynthesis pathway seems to be different in its final steps from that described in land plants. Thus, our work illustrates the potential of GSMNs reconstructions for formalizing hypotheses that can be further tested using targeted biochemical approaches.

scholarly journals Persistent virus integration into the genome of its algal host, Ectocarpus siliculosus (Phaeophyceae).

1999 ◽  
Vol 80 (6) ◽  
pp. 1367-1370 ◽  
Author(s):  
N Delaroque ◽  
I Maier ◽  
R Knippers ◽  
D G Müller
Keyword(s):  
Ectocarpus Siliculosus ◽  
Algal Host ◽  
Persistent Virus ◽  
Virus Integration

Characterization of the in vitro production of N-acyl homoserine lactones by cultivable bacteria inhabiting the sponge Suberites domuncula

2016 ◽  
Vol 97 (1) ◽  
pp. 119-127
Author(s):  
Jasnizat Bin Saidin ◽  
Mohd Effendy Abd Wahid ◽  
Gaël Le Pennec
Keyword(s):  
In Vitro Production ◽  
Form Complex ◽  
Suberites Domuncula ◽  
Associated Bacteria ◽  
Homoserine Lactones ◽  
Cultivable Bacteria ◽  
Acyl Homoserine Lactones ◽  
Vitro Production

Sponges together with associated bacteria form complex holobionts governed by various relationships established between the partners. Molecules of communication may participate in the homeostasis of these biological associations. Bacteria produce N-acyl homoserine lactones to communicate. In the present study, we characterized 102 cultivable bacteria isolated from the sponge Suberites domuncula at the genus level and described their production of AHLs during 96 h of culture in a Marine Broth medium. The presence of AHLs was monitored using the Escherichia coli pSB406 reporter strain. Sixty-seven bacteria were AHLs positive. Among them, 46 were related to the Gammaproteobacteria, eight to the Alphaproteobacteria, seven to the Firmicutes and six to the Flavobacteria. The kinetic production of AHLs was determined and compared with a reference bacterium, Pseudomonas aeruginosa PAO1 (pDA224). We established three profiles of AHLs production with no definitive pattern related to an order, a family or a genus of bacteria.

Application of Molecular Modelling Techniques to Pheromones of the Marine Brown Algae Cutleria multifida and Ectocarpus siliculosus (Phaeophyceae). Metalloproteins as Chemoreceptors?

1989 ◽  
Vol 44 (9-10) ◽  
pp. 829-837 ◽  
Author(s):  
Wilhelm Boland ◽  
Franz-Peter Hoever ◽  
Bernd-Wieland Krüger
Keyword(s):  
Data Base ◽  
Molecular Mechanics ◽  
Molecular Modelling ◽  
Metal Cation ◽  
Brown Algae ◽  
Software Package ◽  
Structural Data ◽  
Molecular Mechanics Calculations ◽  
Ectocarpus Siliculosus ◽  
Modelling Techniques

The conformation of the two algal pheromones ectocarpene (1) and multifidene (2) was studied by the active analogue approach using molecular mechanics calculations within the software package SYBYL. A common conformation for both pheromones and all active analogues was filtered out by superposition- and energy minimizing procedures starting from crystallographic data of the Cambridge Structural Data Base (CSD). The interaction of the algal receptor systems with their olefinic pheromones and heteroanalogues is in excellent agreement with the assumption of a receptor-bound metal cation acting as the binding side.

scholarly journals Need for Laboratory Ecosystems To Unravel the Structures and Functions of Soil Microbial Communities Mediated by Chemistry

mBio ◽  
2018 ◽  
Vol 9 (4) ◽  
Author(s):  
Kateryna Zhalnina ◽  
Karsten Zengler ◽  
Dianne Newman ◽  
Trent R. Northen
Keyword(s):  
Microbial Communities ◽  
Metabolic Networks ◽  
Soil Microbial Communities ◽  
Microbial Interactions ◽  
Microbial Consortia ◽  
Cellular Biology ◽  
Model Organisms ◽  
Soil Microbial ◽  
Integrative Framework ◽  
Genome Annotations

ABSTRACTThe chemistry underpinning microbial interactions provides an integrative framework for linking the activities of individual microbes, microbial communities, plants, and their environments. Currently, we know very little about the functions of genes and metabolites within these communities because genome annotations and functions are derived from the minority of microbes that have been propagated in the laboratory. Yet the diversity, complexity, inaccessibility, and irreproducibility of native microbial consortia limit our ability to interpret chemical signaling and map metabolic networks. In this perspective, we contend that standardized laboratory ecosystems are needed to dissect the chemistry of soil microbiomes. We argue that dissemination and application of standardized laboratory ecosystems will be transformative for the field, much like how model organisms have played critical roles in advancing biochemistry and molecular and cellular biology. Community consensus on fabricated ecosystems (“EcoFABs”) along with protocols and data standards will integrate efforts and enable rapid improvements in our understanding of the biochemical ecology of microbial communities.

scholarly journals Detection of Differential Host Susceptibility to the Marine Oomycete Pathogen Eurychasma dicksonii by Real-Time PCR: Not All Algae Are Equal

2008 ◽  
Vol 75 (2) ◽  
pp. 322-328 ◽  
Author(s):  
Claire M. M. Gachon ◽  
Martina Strittmatter ◽  
Dieter G. Müller ◽  
Julia Kleinteich ◽  
Frithjof C. Küpper
Keyword(s):  
Real Time ◽  
Brown Algae ◽  
Large Scale ◽  
Natural Populations ◽  
Host Susceptibility ◽  
Ecosystem Structure ◽  
Ectocarpus Siliculosus ◽  
Real Time Quantitative Pcr ◽  
Field Samples ◽  
Oomycete Pathogen

ABSTRACT In the marine environment, a growing body of evidence points to parasites as key players in the control of population dynamics and overall ecosystem structure. However, their prevalence and impact on marine macroalgal communities remain virtually unknown. Indeed, infectious diseases of seaweeds are largely underdocumented, partly because of the expertise required to diagnose them with a microscope. Over the last few years, however, real-time quantitative PCR (qPCR) has emerged as a rapid and reliable alternative to visual symptom scoring for monitoring pathogens. Thus, we present here a qPCR assay suitable for the detection and quantification of the intracellular oomycete pathogen Eurychasma dicksonii in its ectocarpalean and laminarialean brown algal hosts. qPCR and microscopic observations made of laboratory-controlled cultures revealed that clonal brown algal strains exhibit different levels of resistance against Eurychasma, ranging from high susceptibility to complete absence of symptoms. This observation strongly argues for the existence of a genetic determinism for disease resistance in brown algae, which would have broad implications for the dynamics and genetic structure of natural populations. We also used qPCR for the rapid detection of Eurychasma in filamentous brown algae collected in Northern Europe and South America and found that the assay is specific, robust, and widely applicable to field samples. Hence, this study opens the perspective of combining large-scale disease monitoring in the field with laboratory-controlled experiments on the genome model seaweed Ectocarpus siliculosus to improve our understanding of brown algal diseases.

Bioaccumulation of 137Cs by benthic plants and macroinvertebrates

2011 ◽  
Vol 40 (3) ◽  
pp. 1-8 ◽  
Author(s):  
Tamara Zalewska ◽  
Michał Saniewski
Keyword(s):  
Baltic Sea ◽  
Brown Algae ◽  
Vascular Plants ◽  
137Cs Activity ◽  
Cladophora Glomerata ◽  
Ectocarpus Siliculosus ◽  
Southern Baltic Sea ◽  
Activity Concentrations ◽  
Concentration Factors ◽  
Isotope Content

Abstract137Cs activity concentrations were determined in macrophytes and macrozoobenthic organisms from the southern Baltic Sea. Cesium isotope content was analysed in macroalgae species (green, red and brown algae representatives) and in some species of vascular plants. The analyzed macroinvertebrate organisms included bivalves and a crustacean.Concentration factors (CF) were calculated using the determined 137Cs concentration in the flora and fauna organisms against that in seawater, and the bioaccumulative properties were compared. The study pointed out that the most important factors in the cesium bioaccumulation process occurring in plants are related to morphology. The highest CF values were obtained in algae Polysiphonia fucoides, Ectocarpus siliculosus and Cladophora glomerata. Decidedly lower CF values were observed in the vascular plants and macrozoobenthos representatives.

scholarly journals Impact of Zirconium on Freshwater Periphytic Microorganisms

Environments ◽  
2019 ◽  
Vol 6 (10) ◽  
pp. 111 ◽  
Author(s):  
Caroline ◽  
Soizic ◽  
Jacky ◽  
Claude
Keyword(s):  
Community Structure ◽  
Toxic Effect ◽  
Indirect Effects ◽  
Brown Algae ◽  
Algal Growth ◽  
Published Data ◽  
Glass Slides ◽  
Time Average ◽  
Biofilm Structure ◽  
Over Time

The majority of studies on biofilms have focused on autotrophic and bacterial taxa, without considering the potential effects on biofilm grazers. In this work, we investigated the effects of realistic environmental concentrations of zirconium (Zr) on periphyton algal growth and micromeiofauna biodiversity. Glass slides were submerged in a pond for four weeks to colonize biofilms and exposed for four weeks in aquaria to targeted Zr concentrations of 0, 1, and 10 nM, which were monitored over time (average measured concentrations were 0.2 ± 0.1, 0.5 ± 0.3, and 2.9 ± 0.3 nM Zr). The four-week exposure to the highest concentration (3 nM) affected the micromeiofauna structure of biofilms and modified the autotrophic biofilm structure by increasing the proportion of green algae and decreasing the abundance of cyanobacteria and brown algae. Rotifers and the ciliate Aspidisca cicada appeared to be the most sensitive organisms among the observed micromeiofauna. A toxic effect of Zr on rotifers could explain such results. Indirect effects, such as reduced food availability given the reduced algal growth in the presence of Zr, could also play a role in the changes of micromeiofauna community structure. These results are among the few published data on the effects of Zr.

Development of automated high-throughput ecotoxicity and genotoxicity test systems and fields of application

2004 ◽  
Vol 50 (5) ◽  
pp. 109-114 ◽  
Author(s):  
A. Eisentraeger ◽  
C. Brinkmann ◽  
K. Michel ◽  
S. Hahn ◽  
M. Huettner ◽  
...  
Keyword(s):  
Growth Inhibition ◽  
High Throughput ◽  
Algal Growth ◽  
Test System ◽  
Growth Inhibition Assay ◽  
Automated Assay ◽  
Genotoxicity Test ◽  
Large Numbers ◽  
Set Up

Bioassays like growth inhibition and genotoxicity assays are frequently used for the characterization of chemicals and contaminated environmental samples. In this work two standardized bioassays are automated completely using newly developed liquid handling stations and robotics. A high-throughput algal growth inhibition assay prototype is set up and optimized in cooperation with Hoelle & Huettner AG (Tuebingen, Germany) and Polygen GmbH (Langen, Germany). A software package for both the control of the test system and for data evaluation has been developed (Biolane(tm) Supervisor, BioLaneTM Manager HTT). The applicability of the prototype is demonstrated by testing reference compounds with the automated assay in parallel with the Erlenmeyer flask assay. It is shown that EC50-values of chemicals do not differ significantly when incubation parameters like homogeneity of light intensity, temperature and evaporation during 72 hours of incubation are optimized. The umu-genotoxicity test is automated completely using a “RoboSeq® 4204 SE” pipetting station (MWG AG, Ebersberg, Germany) equipped with two shakers, microplate photometer, four pipettes, stacker for ten microplates and incubation cabin with temperature regulation. As a result of miniaturization and automation large numbers of toxicants and far more treatments and parallels can be tested and, additionally, only low sample volumes are needed.

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