Possible evidence for panspermia: the labelled release experiment

2007 ◽  
Vol 6 (2) ◽  
pp. 95-108 ◽  
Author(s):  
Gilbert V. Levin
Keyword(s):  
Active Agent ◽  
Life Forms ◽  
Current Data ◽  
Release Experiment ◽  
Microbial Life ◽  
Martian Soil ◽  
Life On Mars ◽  
Biological Interpretation ◽  
Life Question ◽  
Chiral Specificity

Abstract30 years after the Viking Mission landed on Mars (20 July 1976) to search for life, despite the positive findings of the Labelled Release (LR) experiment, the issue remains unresolved. The controversial history, following the immediate dismissal of the LR’s evidence for microbial activity in the Martian soil, and the later claim to its having found living microorganisms are reviewed. The bearing of post-Viking-to-current data on the issue is discussed in the context of the scientific community’s growing interest in the long-dismissed possibility of microbial life on Mars. Objections raised over the years to the biological interpretation of the Mars LR, those currently maintained, and their rebuttals are reviewed. A case is presented that enough evidence now exists for an objective review by astrobiologists to resolve this key issue, a review, surprisingly, not yet held. The results could greatly influence NASA’s currently shifting plans for Mars exploration. A variation of the LR experiment to test for chiral specificity in the metabolism of substrates by the active agent found in the Martian soil, and thus having the capability of obtaining an unambiguous answer to the life question, is proposed. Confirmation of life on Mars by this experiment can also determine whether Martian and Earth life forms share a common heritage. Together with mounting evidence for the viable transfer of microorganisms between the two planets, this would be evidence for panspermia, and establish the presence of a common biosphere in which the two planets participate. Should Martian microorganisms show a different chiral specificity than that of Earth life then this would indicate separate origins of the two neighbouring life forms, thereby strongly implying that life occurs widely throughout the cosmos. Any one of these possible outcomes would be a paradigm-breaking event.

scholarly journals EXPERIMENTO DE LIBERACIÓN ISOTÓPICA MARCADA (LR) Y LA BÚSQUEDA DE VIDA EN MARTE

2019 ◽  
pp. 31-34
Keyword(s):  
Organic Material ◽  
Gas Evolution ◽  
Release Experiment ◽  
Martian Soil ◽  
Palabras Clave ◽  
Life On Mars ◽  
Reactive Oxidants ◽  
Made In

EXPERIMENTO DE LIBERACIÓN ISOTÓPICA MARCADA (LR) Y LA BÚSQUEDA DE VIDA EN MARTE LABELED RELEASE EXPERIMENT (LR) AND THE SEARCH FOR LIFE ON MARS Julio E. Valdivia-Silva, Paola Medina, Aura Palma, Bertha Torres, Rafael Navarro-González DOI: https://doi.org/10.33017/RevECIPeru2009.0007/ RESUMEN Las misiones Vikingo en los 70’s mostraron que el suelo marciano presentaba tres características importantes: ausencia de vida, ausencia de material orgánico, y presencia de uno o varios oxidantes altamente reactivos. Esta conclusión fue realizada gracias a cuatro experimentos que iban a bordo, uno de los cuales se denominó Liberación Isotópica Marcada (LR). En este experimento la liberación de CO2 fue monitoreada luego de la adición de nutrientes marcados isotópicamente con Carbono-14 a muestras del suelo marciano. El presente trabajo resume los resultados de este experimento encontrados por la sonda Vikingo y compara los resultados con otros realizados en suelos terrestres análogos a Marte. Palabras clave: Misión Vikingo, Búsqueda de vida en Marte, Astrobiología, Experimento de Liberación Marcada. ABSTRACT The Viking mission at the 70’s showed the Martian soil to have three important characteristics: absence of life, absence of organic material and the presence of one or more highly reactive oxidants. This conclusion was made due to four experiments on board of Viking spacecraft, one of whom was named Labeled Release Experiment (LR). In this experiment gas evolution was monitored after the addition of nutrients 14C-labeled to Martian soils. The present work summarizes the results found by the Viking and compares these data with others made in terrestrial Mars-like soils. Keywords: Viking mission, Search of Life on Mars, Astrobiology, Labeled Release Experiment.

The case for life on Mars

2008 ◽  
Vol 7 (2) ◽  
pp. 117-141 ◽  
Author(s):  
Dirk Schulze-Makuch ◽  
Alberto G. Fairén ◽  
Alfonso F. Davila
Keyword(s):  
Great Success ◽  
Detection Experiment ◽  
Microbial Life ◽  
Life On Mars ◽  
Extremophilic Microorganisms ◽  
Chain Of Evidence ◽  
Life Detection ◽  
Water On Mars ◽  
Cumulative Evidence ◽  
Early Biosphere

AbstractThere have been several attempts to answer the question of whether there is, or has ever been, life on Mars. The boldest attempt was the only ever life detection experiment conducted on another planet: the Viking mission. The mission was a great success, but it failed to provide a clear answer to the question of life on Mars. More than 30 years after the Viking mission our understanding of the history and evolution of Mars has increased vastly to reveal a wetter Martian past and the occurrence of diverse environments that could have supported microbial life similar to that on Earth for extended periods of time. The discovery of Terran extremophilic microorganisms, adapted to environments previously though to be prohibitive for life, has greatly expanded the limits of habitability in our Solar System, and has opened new avenues for the search of life on Mars. Remnants of a possible early biosphere may be found in the Martian meteorite ALH84001. This claim is based on a collection of facts and observations consistent with biogenic origins, but individual links in the collective chain of evidence remain controversial. Recent evidence for contemporary liquid water on Mars and the detection of methane in the Martian atmosphere further enhance the case for life on Mars. We argue that, given the cumulative evidence provided, life has and is likely to exist on Mars, and we have already found evidence of it. However, to obtain a compelling certainty a new mission is needed, one which is devoted to the detection of life on Mars.

scholarly journals The Atacama Desert in Northern Chile as an Analog Model of Mars

2022 ◽  
Vol 8 ◽  
Author(s):  
Armando Azua-Bustos ◽  
Carlos González-Silva ◽  
Alberto G. Fairén
Keyword(s):  
Atacama Desert ◽  
Analog Model ◽  
Patchy Distribution ◽  
Microbial Life ◽  
Environmental Extremes ◽  
Life On Mars ◽  
Domains Of Life ◽  
Mars Analog ◽  
The Impact

The Atacama Desert is by far the driest and oldest desert on Earth, showing a unique combination of environmental extremes (extreme dryness, the highest UV radiation levels on Earth, and highly saline and oxidizing soils), explaining why the Atacama has been largely investigated as a Mars analog model for almost 20 years. Based on the source and the amount of water available for life and its analogy with Mars, two ecosystems are of interest in the Atacama: its Coastal Range and the much drier hyperarid core, which we here review in detail. Members of the three domains of life have been found across these ecosystems living at the limit of habitability, suggesting the potential dry limits for each domain and also unveiling the highly patchy distribution of microbial life in its most extreme regions. The thorough study of the Atacama has allowed us to understand how life has adapted to its extreme conditions, the specific habitats that life occupies in each case (thus suggesting the most likely places in which to search for evidence for life on Mars), and the number of biosignatures detected across this desert. Also, the characterization of west-to-east transects across this desert has shown to be of significant value to understand the potential adaptations that Martian microorganisms may have followed in an ever-drying planet. All of this explains why the Atacama is actively used as the testing ground of the technologies (detection instruments, rovers, etc.) that were sent and will be sent to Mars. We also highlight the need to better inform the exact locations of the sites studied to understand general trends, the need to identify the true native microbial species of the Atacama, and the impact of climate change on the most arid and most Martian desert of Earth.

scholarly journals Sodium Dichloroisocyanurate: An eco-friendly chemical alternative for media autoclaving and explant sterilisation in plant tissue culture

2021 ◽  
Vol 12 (1) ◽  
pp. 107-112
Author(s):  
Simran Chandrahas Shetty ◽  
Narasimhan S
Keyword(s):  
Tissue Culture ◽  
Plant Tissue Culture ◽  
Plant Tissue ◽  
Active Agent ◽  
Electrical Energy ◽  
Life Forms ◽  
Water Soluble ◽  
Viable Alternative ◽  
Sodium Dichloroisocyanurate

Autoclaving nutrient media is still considered as the optimum mode of sterilisation in plant cell and tissue culture. During the process steam under high pressure is maintained at 120 degrees Celsius, 15 psi for 15-20 minutes in a chamber, optimised to kill all possible microbial life forms. But the disadvantages related to the process of autoclaving are plentiful. They are, decrease in the media pH, salt precipitation, agar depolymerisation, carbohydrate hydrolysis, volatile obliteration and necessity of the infrastructure investment. Requirements of additional resources (time, human resources, electrical energy) have forced the lookout for a more viable alternative, that is, chemical sterilisation. The use of Sodium dichloroisocyanurate (NaDCC) is a useful alternative for media and explant sterilisation. NaDCC is stable, water-soluble, non-toxic and easy to use at room temperature, does not have any environmental hazards and is not phytotoxic. The use of NaDCC as a disinfectant has been documented well concerning water sterilisation, surface sterilisation and also as a broad spectrum disinfecting agent. Disinfecting property of NaDCC is due to the hydrolytic release of chlorine, and this can be utilised for sterilisation of media and explants in plant tissue culture. NaDCC is a useful alternative for autoclaving at a concentration range of 0.05 to 1.0 g/l. However, only a few reports are available for its use as a sterilising agent for media and explants for in vitro cultures of plants. This paper discusses and reviews the possibility of establishing NaDCC as an active agent for explant sterilisation and as a viable alternative to medium sterilisation through autoclaving.

scholarly journals Catalytic/Protective Properties of Martian Minerals and Implications for Possible Origin of Life on Mars

Life ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 56 ◽  
Author(s):  
Teresa Fornaro ◽  
Andrew Steele ◽  
John Brucato
Keyword(s):  
Organic Compounds ◽  
Building Blocks ◽  
Life Forms ◽  
Degradation Mechanisms ◽  
Protective Properties ◽  
Origin And Evolution ◽  
Life On Mars ◽  
Insight Into ◽  
Shed Light

Minerals might have played critical roles for the origin and evolution of possible life forms on Mars. The study of the interactions between the “building blocks of life” and minerals relevant to Mars mineralogy under conditions mimicking the harsh Martian environment may provide key insight into possible prebiotic processes. Therefore, this contribution aims at reviewing the most important investigations carried out so far about the catalytic/protective properties of Martian minerals toward molecular biosignatures under Martian-like conditions. Overall, it turns out that the fate of molecular biosignatures on Mars depends on a delicate balance between multiple preservation and degradation mechanisms, often regulated by minerals, which may take place simultaneously. Such a complexity requires more efforts in simulating realistically the Martian environment in order to better inspect plausible prebiotic pathways and shed light on the nature of the organic compounds detected both in meteorites and on the surface of Mars through in situ analysis.

scholarly journals Acceleration of amino acid racemization by isovaline: possible implications for homochirality and biosignature search

2020 ◽  
Vol 19 (3) ◽  
pp. 276-282
Author(s):  
Stefan Fox ◽  
Annika Gspandl ◽  
Franziska M. Wenng
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Enantiomeric Excess ◽  
Terrestrial Planet ◽  
Microbial Life ◽  
Amino Acid Racemization ◽  
Geothermal Heating ◽  
Life On Mars ◽  
Volcanic Islands ◽  
Life On Earth

AbstractIn nature, abiotically formed amino acids are usually racemic. However, this is not true for the α,α-dialkyl amino acid isovaline (Iva), which has an L-enantiomeric excess in some specimens of carbonaceous meteorites. On the early Earth and Mars, such meteorites were sources of amino acids, including Iva. Therefore, a connection may exist between the possible chiral influence of non-racemic Iva and the origin of biological homochirality. On the surface of a young terrestrial planet, amino acids can be chemically altered in many ways. For example, high temperatures from geothermal heating can lead to racemization. Four billion years ago, active volcanism and volcanic islands provided suitable conditions for such reactions and perhaps even for early microbial life on Earth. In the current study, we investigated the influence of D- and L-Iva on the thermal racemization of L-alanine (L-Ala) and L-2-aminobutyric acid (L-Abu) in a simulated hot volcanic environment. The amino acids were intercalated in the clay mineral calcium montmorillonite (SAz-1). While Iva was resistant to racemization, partial racemization was observed for Ala and Abu after 8 weeks at 150°C. The experimental results – for example, accelerated racemization in the presence of Iva and different influences of the Iva enantiomers – suggest that the amino acid molecules interacted with each other, possibly in hydrogen-bonded dimers. Accelerated racemization of amino acids could have been an obstacle to the development of homochirality. Besides, it is also detrimental to the use of homochirality as a biosignature, for example, in the search for microbial life on Mars.

scholarly journals Survivability of Anhydrobiotic Cyanobacteria in Salty Ice: Implications for the Habitability of Icy Worlds

Life ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 86 ◽  
Author(s):  
Barbara Cosciotti ◽  
Amedeo Balbi ◽  
Alessandra Ceccarelli ◽  
Claudia Fagliarone ◽  
Elisabetta Mattei ◽  
...  
Keyword(s):  
Low Temperature ◽  
Eutectic Temperature ◽  
Life Forms ◽  
Dry Valleys ◽  
Nacl Solution ◽  
Microbial Life ◽  
Icy Moons ◽  
Liquid Solutions ◽  
Eutectic Concentration ◽  
Experimental Runs

Two anhydrobiotic strains of the cyanobacterium Chroococcidiopsis, namely CCMEE 029 and CCMEE 171, isolated from the Negev Desert in Israel and from the Dry Valleys in Antarctica, were exposed to salty-ice simulations. The aim of the experiment was to investigate the cyanobacterial capability to survive under sub-freezing temperatures in samples simulating the environment of icy worlds. The two strains were mixed with liquid solutions having sub-eutectic concentration of Na2SO4, MgSO4 and NaCl, then frozen down to different final temperatures (258 K, 233 K and 203 K) in various experimental runs. Both strains survived the exposure to 258 K in NaCl solution, probably as they migrated in the liquid veins between ice grain boundaries. However, they also survived at 258 K in Na2SO4 and MgSO4-salty-ice samples—that is, a temperature well below the eutectic temperature of the solutions, where liquid veins should not exist anymore. Moreover, both strains survived the exposure at 233 K in each salty-ice sample, with CCMEE 171 showing an enhanced survivability, whereas there were no survivors at 203 K. The survival limit at low temperature was further extended when both strains were exposed to 193 K as air-dried cells. The results suggest that vitrification might be a strategy for microbial life forms to survive in potentially habitable icy moons, for example in Europa’s icy crust. By entering a dried, frozen state, they could be transported from niches, which became non-habitable to new habitable ones, and possibly return to metabolic activity.

Where is the nitrogen on Mars?

2003 ◽  
Vol 2 (3) ◽  
pp. 217-225 ◽  
Author(s):  
Rocco L. Mancinelli ◽  
Amos Banin
Keyword(s):  
Organic Molecules ◽  
Essential Element ◽  
Crystal Lattices ◽  
Origin And Evolution ◽  
Thermal Escape ◽  
Martian Soil ◽  
Evolution Of Life ◽  
Life On Mars ◽  
Nitrogen Abundance ◽  
Living Organisms

Nitrogen is an essential element for life. Specifically, fixed nitrogen (i.e. NH3, NH4+, NOx or N that is chemically bound to either inorganic or organic molecules and can be released by hydrolysis to form NH3 or NH4+) is useful to living organisms. Nitrogen on present-day Mars has been analysed only in the atmosphere. The inventory is a small fraction of the amount of nitrogen presumed to have been received by the planet during its accretion. Where is the missing nitrogen? Answering this question is crucial for understanding the probability of the origin and evolution of life on Mars, and for its future astrobiological exploration. The two main processes that could have removed nitrogen from the atmosphere include: (1) non-thermal escape of N atoms to space and (2) burial within the regolith as nitrates and ammonium salts. Nitrate would probably be stable in the highly oxidized surface soil of Mars and could have served as an NO3− sink. Such accumulations are observed in certain desert environments on Earth. Some NH4+ nitrogen may also be fixed and stabilized in the soil by inclusion as a structural cation in the crystal lattices of certain phyllosilicates replacing K+. Analysis of the Martian soil for traces of NO3− and NH4+ during future missions will provide important information regarding the nitrogen abundance on Mars. We hypothesize that Mars soil, as typical of extremely dry desert soils on Earth, is likely to contain at least some of the missing nitrogen as nitrate salts and some fixed ammonium bound to aluminosilicate minerals.

scholarly journals New Insights into the Search for Life on Mars

2021 ◽  
Author(s):  
Cesare Guaita
Keyword(s):  
Perchloric Acid ◽  
Organic Molecules ◽  
Organic Substances ◽  
Release Experiment ◽  
Gale Crater ◽  
Life On Mars ◽  
Complex Organic ◽  
Positive Results ◽  
14Co2 Release ◽  
Acid Salts

The discovery by the Lander Phoenix (summer 2008) that the Mars polar soil is rich of perchloric acid salts (Na, Mg, Ca perchlorate) strongly could change the interpretation of the Martian experiment of 14CO2 release (LR, Labeled release experiment), performed in 70’s by both Viking Landers. The LR experiment gave substantially positive results but, at that time, possibility of Martian bacteria was ruled out because the CGMS instruments on board of both Vikings didn’t detect any trace of complex organic molecules. But Martian organics exist and were found in fair quantities by Curiosity, landed inside the Gale crater on 2012. So it is likely that Viking CGMS, working at about 500°C, could not see any organic substances (natural or bacterial) because, at that temperature, perchlorates decompose, releasing Oxygen that destroyed organics BEFORE their detection. In any case, the discovery of keragenic compounds by Curiosity, could also be indication of a presence of archea bacteria in the distant past of Mars, when the atmosphere of the Red Planet was wetter and denser than now.

The Language of Iconica

Leonardo ◽  
2001 ◽  
Vol 34 (3) ◽  
pp. 255-259 ◽  
Author(s):  
Troy Innocent
Keyword(s):  
Interface Design ◽  
Active Agent ◽  
Evolutionary Process ◽  
Building Blocks ◽  
Life Forms ◽  
Human Interaction ◽  
Mediated Communication ◽  
Life Model ◽  
Electronically Mediated Communication ◽  
Iconic Language

Visual languages play an important role in electronically mediated communication. In particular, iconography has developed as an important component of user interface design. Interactivity makes an icon an active agent in communication, rather than a passive communicator. The author's interactive work Iconica uses icons to represent the function and structure of an artificial-life model. In this work, iconic elements are the basic building blocks of a world literally made of language. This world has the capacity to evolve, change and mutate through human interaction and its own evolutionary process. Communication with the resident life forms occurs via the iconic language that defines the world, including its elements, forms, entities, spaces and behaviors.

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