scholarly journals Influence of CH<sub>4</sub> and H<sub>2</sub>S availability on symbiont distribution, carbon assimilation and transfer in the dual symbiotic vent mussel <i>Bathymodiolus azoricus</i>

2008 ◽  
Vol 5 (6) ◽  
pp. 1681-1691 ◽  
Author(s):  
V. Riou ◽  
S. Halary ◽  
S. Duperron ◽  
S. Bouillon ◽  
M. Elskens ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Hydrothermal Vents ◽  
Inorganic Carbon ◽  
Carbon Assimilation ◽  
Gill Tissue ◽  
Mid Atlantic Ridge ◽  
Set Up ◽  
High Level ◽  
Substrate Concentrations

Abstract. High densities of mussels of the genus Bathymodiolus are present at hydrothermal vents of the Mid-Atlantic Ridge. It was previously proposed that the chemistry at vent sites would affect their sulphide- and methane-oxidizing endosymbionts' abundance. In this study, we confirmed the latter assumption using fluorescence in situ hybridization on Bathymodiolus azoricus specimens maintained in a controlled laboratory environment at atmospheric pressure with one, both or none of the chemical substrates. A high level of symbiosis plasticity was observed, methane-oxidizers occupying between 4 and 39% of total bacterial area and both symbionts developing according to the presence or absence of their substrates. Using H13CO3− in the presence of sulphide, or 13CH4, we monitored carbon assimilation by the endosymbionts and its translocation to symbiont-free mussel tissues. Carbon was incorporated from methane and sulphide-oxidized inorganic carbon at rates 3 to 10 times slower in the host muscle tissue than in the symbiont-containing gill tissue. Both symbionts thus contribute actively to B. azoricus nutrition and adapt to the availability of their substrates. Further experiments with varying substrate concentrations using the same set-up should provide useful tools to study and even model the effects of changes in hydrothermal fluids on B. azoricus' chemosynthetic nutrition.

scholarly journals Influence of chemosynthetic substrates availability on symbiont densities, carbon assimilation and transfer in the dual symbiotic vent mussel <I>Bathymodiolus azoricus</I>

2008 ◽  
Vol 5 (3) ◽  
pp. 2279-2304 ◽  
Author(s):  
V. Riou ◽  
S. Halary ◽  
S. Duperron ◽  
S. Bouillon ◽  
M. Elskens ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Hydrothermal Vents ◽  
Inorganic Carbon ◽  
Carbon Assimilation ◽  
Gill Tissue ◽  
Mid Atlantic Ridge ◽  
Set Up ◽  
High Level ◽  
Substrate Concentrations

Abstract. High densities of mussels of the genus Bathymodiolus are present at hydrothermal vents of the Mid-Atlantic Ridge. It was already proposed that the chemistry at vent sites would affect their sulphide- and methane-oxidizing endosymbionts' abundance. In this study, we confirmed the latter assumption using fluorescence in situ hybridization on Bathymodiolus azoricus specimens maintained in a controlled laboratory environment at atmospheric pressure with one, both or none of the chemical substrates. A high level of symbiosis plasticity was observed, methane-oxidizers occupying between 4 and 39% of total bacterial area and both symbionts developing accordingly to the presence or absence of their substrates. Using H13CO3− in the presence of sulphide, 13CH4 or 13CH3OH, we monitored carbon assimilation by the endosymbionts and its translocation to symbiont-free mussel tissues. Although no significant carbon assimilation could be evidenced with methanol, carbon was incorporated from methane and sulphide-oxidized inorganic carbon at rates 3 to 10 times slower in the host muscle tissue than in the symbiont-containing gill tissue. Both symbionts thus contribute actively to B. azoricus nutrition and adapt to the availability of their substrates. Further experiments with varying substrate concentrations using the same set-up should provide useful tools to study and even model the effects of changes in hydrothermal fluids on B. azoricus' chemosynthetic nutrition.

scholarly journals MoMAR-D: a technological challenge to monitor the dynamics of the Lucky Strike vent ecosystem

2010 ◽  
Vol 68 (2) ◽  
pp. 416-424 ◽  
Author(s):  
A. Colaço ◽  
J. Blandin ◽  
M. Cannat ◽  
T. Carval ◽  
V. Chavagnac ◽  
...  
Keyword(s):  
Hydrothermal Vents ◽  
Multidisciplinary Approach ◽  
Satellite Communication ◽  
Ecosystem Dynamics ◽  
Lucky Strike ◽  
Volcanic Events ◽  
Mid Atlantic Ridge ◽  
Technological Challenge ◽  
Set Up

Abstract Colaço, A., Blandin, J., Cannat, M., Carval, T., Chavagnac, V., Connelly, D., Fabian, M., Ghiron, S., Goslin, J., Miranda, J. M., Reverdin, G., Sarrazin, J., Waldmann, C., and Sarradin, M. 2011. MoMAR-D: a technological challenge to monitor the dynamics of the Lucky Strike vent ecosystem. – ICES Journal of Marine Science, 68: 416–424. The MoMAR (monitoring the Mid-Atlantic Ridge) project was initiated in 1998 by the InterRidge programme to promote and coordinate long-term multidisciplinary monitoring of hydrothermal vents at the Mid-Atlantic Ridge (MAR). The major objective of the project is to study vent ecosystem dynamics using a multidisciplinary approach from geophysics to microbiology over a period of a few decades. MoMAR-D is a demonstration project of MoMAR, partially funded by the European network of excellence ESONET (http://www.esonet-noe.org/). MoMAR-D aims to deploy and manage a multidisciplinary observing system at the Lucky Strike vent field for 1 year. This large hydrothermal field is located at the centre of one of the most volcanically active segments of the MAR. The project has been set up to monitor this region to capture evidence of volcanic events, observe interactions between faulting, magmatism, and hydrothermal circulations, and to evaluate the potential impacts of these environmental factors on the unusual communities colonizing hydrothermal vents. The MoMAR-D infrastructure consists of two sea monitoring nodes (SEAMON) acoustically linked to a surface buoy with satellite communication to a land-based station. The first node will be mainly dedicated to geophysical studies, whereas the second will focus on ecological studies and chemical fluxes. The infrastructure should have been deployed in September 2010 during the MoMARSAT cruise.

scholarly journals Tracing carbon assimilation in endosymbiotic deep-sea hydrothermal vent Mytilid fatty acids by <sup>13</sup>C-fingerprinting

2010 ◽  
Vol 7 (9) ◽  
pp. 2591-2600 ◽  
Author(s):  
V. Riou ◽  
S. Bouillon ◽  
R. Serrão Santos ◽  
F. Dehairs ◽  
A. Colaço
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Metabolic Pathways ◽  
Hydrothermal Vents ◽  
Carbon Assimilation ◽  
Phenotypic Characteristics ◽  
Endosymbiotic Bacteria ◽  
Carbon Compounds ◽  
Bacterial Endosymbionts ◽  
Mid Atlantic Ridge

Abstract. Bathymodiolus azoricus mussels thrive at Mid-Atlantic Ridge hydrothermal vents, where part of their energy requirements are met via an endosymbiotic association with chemolithotrophic and methanotrophic bacteria. In an effort to describe phenotypic characteristics of the two bacterial endosymbionts and to assess their ability to assimilate CO2, CH4 and multi-carbon compounds, we performed experiments in aquaria using 13C-labeled NaHCO3 (in the presence of H2S), CH4 or amino-acids and traced the incorporation of 13C into total and phospholipid fatty acids (tFA and PLFA, respectively). 14:0; 15:0; 16:0; 16:1(n − 7)c+t; 18:1(n − 13)c+t and (n − 7)c+t; 20:1(n − 7); 20:2(n − 9,15); 18:3(n − 7) and (n − 5,10,13) PLFA were labeled in the presence of H13CO3− (+H2S) and 13CH4, while the 12:0 compound became labeled only in the presence of H13CO3− (+H2S). In contrast, the 17:0; 18:0; 16:1(n − 9); 16:1(n − 8) and (n − 6); 18:1(n − 8); and 18:2(n − 7) PLFA were only labeled in the presence of 13CH4. Some of these symbiont-specific fatty acids also appeared to be labeled in mussel gill tFA when incubated with 13C-enriched amino acids, and so were mussel-specific fatty acids such as 22:2(n − 7,15). Our results provide experimental evidence for the potential of specific fatty acid markers to distinguish between the two endosymbiotic bacteria, shedding new light on C1 and multi-carbon compound metabolic pathways in B. azoricus and its symbionts.

scholarly journals Validating the Cyc2 neutrophilic Fe oxidation pathway using meta-omics of Zetaproteobacteria iron mats at marine hydrothermal vents

2019 ◽  
Author(s):  
Sean M. McAllister ◽  
Shawn W. Polson ◽  
David A. Butterfield ◽  
Brian T. Glazer ◽  
Jason B. Sylvan ◽  
...  
Keyword(s):  
Hydrothermal Vents ◽  
Carbon Fixation ◽  
Central Metabolism ◽  
Ideal Model ◽  
Oxidase Gene ◽  
Oxidation Pathway ◽  
Fe Oxidation ◽  
Mid Atlantic Ridge ◽  
Metabolism Gene

AbstractZetaproteobacteria create extensive iron (Fe) oxide mats at marine hydrothermal vents, making them an ideal model for microbial Fe oxidation at circumneutral pH. Comparison of neutrophilic Fe-oxidizer isolate genomes has revealed a hypothetical Fe oxidation pathway, featuring a homolog of the Fe oxidase Cyc2 from Acidithiobacillus ferrooxidans. However, Cyc2 function is not well verified in neutrophilic Fe-oxidizers, particularly in Fe-oxidizing environments. Toward this, we analyzed genomes and metatranscriptomes of Zetaproteobacteria, using 53 new high-quality metagenome assembled genomes reconstructed from Fe mats at Mid-Atlantic Ridge, Mariana Backarc, and Loihi Seamount (Hawaii) hydrothermal vents. Phylogenetic analysis demonstrated conservation of Cyc2 sequences among most neutrophilic Fe-oxidizers, suggesting a common function. We confirmed the widespread distribution of cyc2 and other model Fe oxidation pathway genes across all represented Zetaproteobacteria lineages. High expression of these genes was observed in diverse Zetaproteobacteria under multiple environmental conditions, and in incubations. The putative Fe oxidase gene, cyc2, was highly expressed in situ, often as the top expressed gene. The cyc2 gene showed increased expression in Fe(II)-amended incubations, with corresponding increases in carbon fixation and central metabolism gene expression. These results substantiate the Cyc2-based Fe oxidation pathway in neutrophiles and demonstrate its significance in marine Fe-mineralizing environments.

scholarly journals Tracing carbon assimilation in endosymbiotic deep-sea hydrothermal vent Mytilid fatty acids by <sup>13</sup>C-fingerprinting

2010 ◽  
Vol 7 (3) ◽  
pp. 3453-3475 ◽  
Author(s):  
V. Riou ◽  
S. Bouillon ◽  
R. Serrão Santos ◽  
F. Dehairs ◽  
A. Colaço
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Hydrothermal Vents ◽  
Carbon Assimilation ◽  
Phenotypic Characteristics ◽  
Endosymbiotic Bacteria ◽  
Carbon Compounds ◽  
Bacterial Endosymbionts ◽  
Mid Atlantic Ridge ◽  
C And N

Abstract. Bathymodiolus azoricus mussels thrive at Mid-Atlantic Ridge hydrothermal vents, where part of their energy requirements are met via an endosymbiotic association with chemolithotrophic and methanotrophic bacteria. In an effort to describe phenotypic characteristics of the two bacterial endosymbionts and to assess their ability to assimilate CO2, CH4 and multi-carbon compounds, we performed experiments in aquaria using 13C-labeled NaHCO3 (in the presence of H2S), CH4 or amino-acids and traced the incorporation of 13C into total and phospholipid fatty acids (tFA and PLFA, respectively). 14:0, 15:0, 16:1(n-7)c+t and 18:1(n-7)c+t PLFA were labeled in the presence of H13CO3- (+H2S) and 13CH4, while the 12:0 compound became labeled only in the presence of H13CO3− (+H2S). In contrast, the 16:1(n-9), 16:1(n-8) and (n-6), 18:1(n-8)c and (n-7), 20:1(n-7) and 18:2(n-7) PLFA were only labeled in the presence of 13CH4. Some of these symbiont-specific fatty acids also appeared to be labeled in mussel gill tFA when incubated with 13C-enriched amino acids, and so were mussel-specific fatty acids such as 22:2(n-7,15). Our results provide experimental evidence for the potential of specific fatty acid markers to distinguish between the two endosymbiotic bacteria, shedding new light on C1 and multi-carbon compound metabolic pathways in B. azoricus and its symbionts.

Onchocerciasis in Osse, Ondo State, Nigeria: Effectiveness of Motivational Strategies in Sustaining Compliance with Community Ivermectin Therapy

2002 ◽  
Vol 21 (2) ◽  
pp. 177-189
Author(s):  
O. U. Manafa ◽  
T. S. Awolola ◽  
A. N. Isamah
Keyword(s):  
Community Intervention ◽  
Intervention Group ◽  
Control Group ◽  
Group Discussions ◽  
Participant Satisfaction ◽  
Attitudes And Practices ◽  
Ondo State ◽  
Set Up ◽  
High Level ◽  
Knowledge Attitudes And Practices

A study in human Onchocerciasis was undertaken in four endemic communities in Ondo State, Nigeria. In-depth interviews were conducted on peoples' knowledge, attitudes, and practices regarding Onchocerciasis aetiology, treatment, prevention, and symptoms. These were complemented by key informant interviews and focus group discussions. Based on this information, an educational program was set up which included the training of selected villagers (motivators) and community intervention organized by these motivators. Evaluation used a control group where intervention was focused on other health problems in the area. Onchocerciasis education took place only with the intervention group. At the start of the project, peoples' knowledge about Onchocerciasis, its cause, treatment, prevention, and symptoms were varied and only a small proportion could link the bite of the blackfly to Onchocerciasis. The educational intervention achieved a high level of participant satisfaction which was expressed in continuous attendance at workshops and keeping appointments with motivators. The intervention helped to bring a significant improvement in the knowledge, attitudes, and practices (KAP) of the respondents. The knowledge of Onchocerciasis aetiology increased to 79.8 percent, 71.5 percent, and 74 percent from 48.5 percent, 48.7 percent, 34 percent, and 45 percent pre-intervention in the four study areas used. The project demonstrated that a community-based health education can be effective in Onchocerciasis control.

Innovative Closed-Cell Reactor Permits In Situ Heating and Gas Reactions with Atomic Resolution at Atmospheric Pressure

2012 ◽  
Vol 18 (S2) ◽  
pp. 1118-1119 ◽  
Author(s):  
L. Allard ◽  
S.H. Overbury ◽  
M.B. Katz ◽  
W.C. Bigelow ◽  
D. Nackashi ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Atomic Resolution ◽  
Closed Cell ◽  
Cell Reactor ◽  
In Situ Heating ◽  
Gas Reactions

Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.

scholarly journals Developing a BIM-Based MUVR Treadmill System for Architectural Design Review and Collaboration

2021 ◽  
Vol 11 (15) ◽  
pp. 6881
Author(s):  
Calvin Chung Wai Keung ◽  
Jung In Kim ◽  
Qiao Min Ong
Keyword(s):  
Architectural Design ◽  
Human Locomotion ◽  
Virtual Space ◽  
Design Stage ◽  
Design Review ◽  
Team Members ◽  
Physical Constraints ◽  
Simulated Environment ◽  
Set Up ◽  
High Level

Virtual reality (VR) is quickly becoming the medium of choice for various architecture, engineering, and construction applications, such as design visualization, construction planning, and safety training. In particular, this technology offers an immersive experience to enhance the way architects review their design with team members. Traditionally, VR has used a desktop PC or workstation setup inside a room, yielding the risk of two users bump into each other while using multiuser VR (MUVR) applications. MUVR offers shared experiences that disrupt the conventional single-user VR setup, where multiple users can communicate and interact in the same virtual space, providing more realistic scenarios for architects in the design stage. However, this shared virtual environment introduces challenges regarding limited human locomotion and interactions, due to physical constraints of normal room spaces. This study thus presented a system framework that integrates MUVR applications into omnidirectional treadmills. The treadmills allow users an immersive walking experience in the simulated environment, without space constraints or hurt potentialities. A prototype was set up and tested in several scenarios by practitioners and students. The validated MUVR treadmill system aims to promote high-level immersion in architectural design review and collaboration.

scholarly journals Comparison of Hydrocarbon-Degrading Consortia from Surface and Deep Waters of the Eastern Mediterranean Sea: Characterization and Degradation Potential

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2246
Author(s):  
Georgia Charalampous ◽  
Efsevia Fragkou ◽  
Konstantinos A. Kormas ◽  
Alexandre B. De Menezes ◽  
Paraskevi N. Polymenakou ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Oil Spills ◽  
Eastern Mediterranean ◽  
Sole Source ◽  
Eastern Mediterranean Sea ◽  
Deep Waters ◽  
Degradation Rates ◽  
Polycyclic Aromatic ◽  
Set Up

The diversity and degradation capacity of hydrocarbon-degrading consortia from surface and deep waters of the Eastern Mediterranean Sea were studied in time-series experiments. Microcosms were set up in ONR7a medium at in situ temperatures of 25 °C and 14 °C for the Surface and Deep consortia, respectively, and crude oil as the sole source of carbon. The Deep consortium was additionally investigated at 25 °C to allow the direct comparison of the degradation rates to the Surface consortium. In total, ~50% of the alkanes and ~15% of the polycyclic aromatic hydrocarbons were degraded in all treatments by Day 24. Approximately ~95% of the total biodegradation by the Deep consortium took place within 6 days regardless of temperature, whereas comparable levels of degradation were reached on Day 12 by the Surface consortium. Both consortia were dominated by well-known hydrocarbon-degrading taxa. Temperature played a significant role in shaping the Deep consortia communities with Pseudomonas and Pseudoalteromonas dominating at 25 °C and Alcanivorax at 14 °C. Overall, the Deep consortium showed a higher efficiency for hydrocarbon degradation within the first week following contamination, which is critical in the case of oil spills, and thus merits further investigation for its exploitation in bioremediation technologies tailored to the Eastern Mediterranean Sea.

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