scholarly journals Proposed Tasks of Enceladus Missions’ Instrumentation in the Context of Their Astrobiological Goals

2020 ◽  
Vol 24 (4) ◽  
pp. 47-56
Author(s):  
Katarzyna Kubiak ◽  
Jan Kotlarz ◽  
Natalia Zalewska ◽  
Urszula Zielenkiewicz
Keyword(s):  
Life Forms ◽  
Model Organisms ◽  
Ocean Bottom ◽  
Mass Spectrometers ◽  
Water Ice ◽  
Lost City ◽  
Optical Channels ◽  
Benzene Toluene ◽  
Lost City Hydrothermal Field ◽  
Saturnian Satellite

Enceladus, Saturnian satellite, is a very significant object for astrobiologists due to the presence of liquid water that forms the ice-covered ocean. Water ice geysers escape from the south pole region through cracks in the ice shield. During the Cassini flight, the probe took samples of plumes matter recognizing besides other methane and molecular hydrogen. Since then, hypotheses have been formulated that life forms similar to those found in the Lost City Hydrothermal Field in the Atlantic ocean bottom may occur near Enceladus’ hydrothermal chimneys. In our work, we analyzed the possibility of a microbial factor detection in the Enceladus geysers. We used as model organisms selected extremophiles. We investigated multi-spectral cameras and mass spectrometers intended for use in mission proposals to Enceladus: Enceladus Orbiter, Enceladus Life Finder, The Explorer of Enceladus and Titan and THEO mission. The review pointed that the configuration of mass spectrometers and the proposed parameters of scientific orbits are appropriate for detecting volatile organic compounds corresponding to selected microorganisms such as aldehyde, ethanol, benzene, toluene, indole, or violacein. The possible presence of a microbiological component with physical dimensions in the order of several micrometres can only be observed for areas of geyser formation at their higher density (> 10 ppm) and with the occurrence of the “snowing microbes” phenomenon. We have found that particularly useful optical channels are 780–975 nm, 860–910 nm, and 5.0–5.3 µm.

scholarly journals Regeneration and the need for simpler model organisms

2004 ◽  
Vol 359 (1445) ◽  
pp. 759-763 ◽  
Author(s):  
Alejandro Sánchez Alvarado
Keyword(s):  
Cell Fate ◽  
Developmental Plasticity ◽  
Functional Integration ◽  
Life Forms ◽  
Tissue Homeostasis ◽  
Model Organisms ◽  
Body Parts ◽  
Tissue Replacement ◽  
Wear And Tear ◽  
Multicellular Organisms

The problem of regeneration is fundamentally a problem of tissue homeostasis involving the replacement of cells lost to normal ‘wear and tear’ (cell turnover), and/or injury. This attribute is of particular significance to organisms possessing relatively long lifespans, as maintenance of all body parts and their functional integration is essential for their survival. Because tissue replacement is broadly distributed among multicellular life–forms, and the molecules and mechanisms controlling cellular differentiation are considered ancient evolutionary inventions, it should be possible to gain key molecular insights about regenerative processes through the study of simpler animals. We have chosen to study and develop the freshwater planarian Schmidtea mediterranea as a model system because it is one of the simplest metazoans possessing tissue homeostasis and regeneration, and because it has become relatively easy to molecularly manipulate this organism. The developmental plasticity and longevity of S. mediterranea is in marked contrast to its better–characterized invertebrate cohorts: the fruitfly Drosophila melanogaster and the roundworm Caenorhabditis elegans , both of which have short lifespans and are poor at regenerating tissues. Therefore, planarians present us with new, experimentally accessible contexts in which to study the molecular actions guiding cell fate restriction, differentiation and patterning, each of which is crucial not only for regeneration to occur, but also for the survival and perpetuation of all multicellular organisms.

scholarly journals Geologic evolution of the Lost City Hydrothermal Field

2016 ◽  
Vol 17 (2) ◽  
pp. 375-394 ◽  
Author(s):  
Alden R. Denny ◽  
Deborah S. Kelley ◽  
Gretchen L. Früh-Green
Keyword(s):  
Hydrothermal Field ◽  
Lost City ◽  
Lost City Hydrothermal Field

scholarly journals Recurrent losses and rapid evolution of the condensin II complex in insectsg

2018 ◽  
Author(s):  
T. King ◽  
C.J. Leonard ◽  
J.C. Cooper ◽  
S. Nguyen ◽  
E. Joyce ◽  
...  
Keyword(s):  
Genome Organization ◽  
Molecular Mechanisms ◽  
Somatic Cells ◽  
Rapid Evolution ◽  
Genetic Material ◽  
Life Forms ◽  
Model Organisms ◽  
Homologous Chromosomes ◽  
Homologous Chromosome Pairing ◽  
Key Aspects

AbstractCondensins play a crucial role in the organization of genetic material by compacting and disentangling chromosomes. The condensin I and condensin II complexes are widely considered to have distinct functions based on studies in a few model organisms, although the specific functions of each complex are yet to be fully understood. The condensin II complex is critical for genome organization in Drosophila, and is a key anti-pairing factor that separates homologous chromosomes in somatic cells. Intriguingly, the Cap-G2 subunit of condensin II is absent in Drosophila melanogaster, and this loss may be related to the high levels of homologous chromosome pairing in somatic cells seen in flies. Here, we find that this Cap-G2 loss predates the origin of Dipterans, and other CapG2 losses have occurred independently in multiple insect lineages. Furthermore, the Cap-H2 and Cap-D3 subunits have also been repeatedly and independently lost in several insect orders, and some taxa lack condensin II-specific subunits entirely. We used Oligopaint DNA-FISH to quantify pairing levels in ten species across seven orders, representing several different configurations of the condensin II complex. We find that all non-Dipteran insects display near-uniform low pairing levels, suggesting that some key aspects of genome organization are robust to condensin II subunit losses. Finally, we observe consistent signatures of positive selection in condensin II subunits across flies and mammals. These findings suggest that these ancient complexes are far more evolutionarily labile than previously suspected, and are at the crossroads of several forms of genomic conflicts. Our results raise fundamental questions about the specific functions of the two condensin complexes and the interplay between them in taxa that have experienced subunit losses, and open the door to further investigations to elucidate the diversity of molecular mechanisms that underlie genome organization across various life forms.

scholarly journals Genomic Evidence for Formate Metabolism by Chloroflexi as the Key to Unlocking Deep Carbon in Lost City Microbial Ecosystems

2019 ◽  
Author(s):  
Julia M. McGonigle ◽  
Susan Q. Lang ◽  
William J. Brazelton
Keyword(s):  
Carbon Cycling ◽  
Hydrothermal Vents ◽  
Reducing Power ◽  
Single Species ◽  
Hydrogen Gas ◽  
Ambient Seawater ◽  
Lost City ◽  
Microbial Life ◽  
Microbial Ecosystems ◽  
Lost City Hydrothermal Field

ABSTRACTThe Lost City hydrothermal field on the Mid-Atlantic Ridge supports dense microbial life on the lofty calcium carbonate chimney structures. The vent field is fueled by chemical reactions between the ultramafic rock under the chimneys and ambient seawater. These serpentinization reactions provide reducing power (as hydrogen gas) and organic compounds that can serve as microbial food; the most abundant of these are methane and formate. Previous studies have characterized the interior of the chimneys as a single-species biofilm inhabited by the Lost City Methanosarcinales, but also indicated that this methanogen is unable to metabolize formate. The new metagenomic results presented here indicate that carbon cycling in these Lost City chimney biofilms could depend on the metabolism of formate by low-abundance Chloroflexi species. Additionally, we present evidence that metabolically diverse, formate-utilizing Sulfurovum species are living in the transition zone between the interior and exterior of the chimneys.IMPORTANCEPrimitive forms of life may have originated around hydrothermal vents at the bottom of the ancient ocean. The Lost City hydrothermal vent field, fueled by just rock and water, provides an analog for not only primitive ecosystems but also extraterrestrial ecosystems that might support life. The microscopic life covering towering chimney structures at the Lost City has been well characterized, yet little is known about the carbon cycling in this ecosystem. These results provide a better understanding of how carbon from the deep subsurface can fuel rich microbial ecosystems on the seafloor.

scholarly journals Genomic Evidence for Formate Metabolism by Chloroflexi as the Key to Unlocking Deep Carbon in Lost City Microbial Ecosystems

2020 ◽  
Vol 86 (8) ◽  
Author(s):  
Julia M. McGonigle ◽  
Susan Q. Lang ◽  
William J. Brazelton
Keyword(s):  
Carbon Cycling ◽  
Hydrothermal Vents ◽  
Reducing Power ◽  
Single Species ◽  
Hydrogen Gas ◽  
Ambient Seawater ◽  
Lost City ◽  
Microbial Life ◽  
Microbial Ecosystems ◽  
Lost City Hydrothermal Field

ABSTRACT The Lost City hydrothermal field on the Mid-Atlantic Ridge supports dense microbial life on the lofty calcium carbonate chimney structures. The vent field is fueled by chemical reactions between the ultramafic rock under the chimneys and ambient seawater. These serpentinization reactions provide reducing power (as hydrogen gas) and organic compounds that can serve as microbial food; the most abundant of these are methane and formate. Previous studies have characterized the interior of the chimneys as a single-species biofilm inhabited by the Lost City Methanosarcinales, but they also indicated that this methanogen is unable to metabolize formate. The new metagenomic results presented here indicate that carbon cycling in these Lost City chimney biofilms could depend on the metabolism of formate by Chloroflexi populations. Additionally, we present evidence for metabolically diverse, formate-utilizing Sulfurovum populations and new genomic and phylogenetic insights into the unique Lost City Methanosarcinales. IMPORTANCE Primitive forms of life may have originated around hydrothermal vents at the bottom of the ancient ocean. The Lost City hydrothermal vent field, fueled by just rock and water, provides an analog for not only primitive ecosystems but also potential extraterrestrial rock-powered ecosystems. The microscopic life covering the towering chimney structures at the Lost City has been previously documented, yet little is known about the carbon cycling in this ecosystem. These results provide a better understanding of how carbon from the deep subsurface can fuel rich microbial ecosystems on the seafloor.

scholarly journals U–Th systematics and 230Th ages of carbonate chimneys at the Lost City Hydrothermal Field

2011 ◽  
Vol 75 (7) ◽  
pp. 1869-1888 ◽  
Author(s):  
Kristin A. Ludwig ◽  
Chuan-Chou Shen ◽  
Deborah S. Kelley ◽  
Hai Cheng ◽  
R. Lawrence Edwards
Keyword(s):  
Hydrothermal Field ◽  
Lost City ◽  
Lost City Hydrothermal Field

Elevated concentrations of formate, acetate and dissolved organic carbon found at the Lost City hydrothermal field

2010 ◽  
Vol 74 (3) ◽  
pp. 941-952 ◽  
Author(s):  
Susan Q. Lang ◽  
David A. Butterfield ◽  
Mitch Schulte ◽  
Deborah S. Kelley ◽  
Marvin D. Lilley
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Hydrothermal Field ◽  
Lost City ◽  
Lost City Hydrothermal Field
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