Microbial Metabolism of Amino Acids—Biologically Induced Removal of Glycine and the Resulting Fingerprint as a Potential Biosignature

The identification of reliable biomarkers, such as amino acids, is key for the search of extraterrestrial life. A large number of microorganisms metabolize, synthesize, take up and excrete amino acids as part of the amino acid metabolism during aerobic and/or anaerobic respiration or in fermentation. In this work, we investigated whether the anaerobic microbial metabolism of amino acids could leave a secondary biosignature indicating biological activity in the environment around the cells. The observed fingerprints would reflect the physiological capabilities of the specific microbial community under investigation. The metabolic processing of an amino acid mixture by two distinct anaerobic microbial communities collected from Islinger Mühlbach (ISM) and Sippenauer Moor (SM), Germany was examined. The amino acid mixture contained L-alanine, β-alanine, L-aspartic acid, DL-proline, L-leucine, L-valine, glycine, L-phenylalanine and L-isoleucine. In parallel, an amino acid spiked medium without microorganisms was used as a control to determine abiotic changes over time. Liquid chromatography mass spectrometry (LC-MS) was used to track amino acid changes over time. When comparing to the control samples that did not show significant changes of amino acids concentrations over time, we found that glycine was almost completely depleted from both microbial samples to less than 3% after the first two weeks- This results indicates a preferential use of this simple amino acid by these microbial communities. Although glycine degradation can be caused by abiotic processes, these results show that its preferential depletion in an environment would be consistent with the presence of life. We found changes in most other amino acids that varied between amino acids and communities, suggesting complex dynamics with no clear universal pattern that might be used as a signature of life. However, marked increases in amino acids, caused by cellular synthesis and release into the extracellular environment (e.g., alanine), were observed and could be considered a signature of metabolic activity. We conclude, that substantial anomalous enhancements of some amino acids against the expected abiotic background concentration may be an agnostic signature of the presence of biological processes

BIOMARKERS DETECTION IN MARS ANALOGUE SITES WITHIN MASE PROJECT

Life is a physico-chemical process by which tell-tale signals or traces are left on the environment. These signals are indicators of life and are known as biomarkers. Besides, the traces of some kinds of microorganisms can be well preserved, provided that they are rapidly mineralized and that the sediments in which they occur are rapidly cemented [1]. The search for these traces of life is one of the main objectives of Mars exploration [1] and to improve and optimize the search and detection of them forms part of MASE project targets. In MASE project (Mars Analogues for Space Exploration) we work to improve approaches and methods for biomarker detection in samples with low biomass from Mars analogue sites. A developed antibody multiarray competitive immunoassay (MACIA) for the simultaneous detection of compounds of a wide range of molecular sizes or whole spores and cells [2] [3] has revealed as suitable option to achieve this purpose

Mars Analogues for space exploration - from anaerobic field site to culture collection

Astrobiology seeks to understand the limits of life and to determine the physiology of organisms in order to be able to better assess the potential habitability of other worlds and improve our ability to assay them for the presence of life. To successfully achieve this we require representative microorganisms from environments on Earth that in physical and/or chemical conditions approximate to extraterrestrial environments. The most challenging of these environments with respect to the sample collection and follow on isolation and cultivation of microorganisms are anaerobic environments. Here we describe a systematic approach to this challenge and aim to provide a guideline for future fieldwork and sampling campaigns. We selected a number of anaerobic environments based on characteristics that make them analogous to past and present locations on Mars (Icelandic lakes, sulfidic springs, deep hypersaline environments, acidic iron-rich environments, and permafrost). We implemented a culturing approach to enrich organisms from these environments under anaerobic conditions using a defined medium that would allow for all organisms to be grown under identical culturing conditions m future physiological comparisons. We then isolated anaerobic microorganisms, carried out a study of their basic physiology and deposited these organisms in the DSMZ (Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH) culture collection to make them available to astrobiologists and microbiologists. This project represents the first attempt to implement a coordinated effort from the selection of extraterrestrial analog sites through to the isolation and the characterisation of organisms and their deposition within a culture collection

Taxonomic and functional analyses of intact microbial communities thriving in extreme, astrobiology-relevant, anoxic sites

Background: Extreme terrestrial, analogue environments are widely used models to study the limits of life and to infer habitability of extraterrestrial settings. In contrast to Earth’s ecosystems, potential extraterrestrial biotopes are usually characterized by a lack of oxygen. Methods: In the MASE project (Mars Analogues for Space Exploration), we selected representative anoxic analogue environments (permafrost, salt-mine, acidic lake and river, sulfur springs) for the comprehensive analysis of their microbial communities. We assessed the microbiome profile of intact cells by propidium monoazide-based amplicon and shotgun metagenome sequencing, supplemented with an extensive cultivation effort. Results: The information retrieved from microbiome analyses on the intact microbial community thriving in the MASE sites, together with the isolation of 31 model microorganisms and successful binning of 15 high-quality genomes allowed us to observe principle pathways, which pinpoint specific microbial functions in the MASE sites compared to moderate environments. The microorganisms were characterized by an impressive machinery to withstand physical and chemical pressures. All levels of our analyses revealed the strong and omnipresent dependency of the microbial communities on complex organic matter. Moreover, we identified an extremotolerant cosmopolitan group of 34 poly-extremophiles thriving in all sites. Conclusions: Our results reveal the presence of a core microbiome and microbial taxonomic similarities between saline and acidic anoxic environments. Our work further emphasizes the importance of the environmental, terrestrial parameters for the functionality of a microbial community, but also reveals a high proportion of living microorganisms in extreme environments with a high adaptation potential within habitability borders

Regulated Fluctuations in Nanog Expression Mediate Cell Fate Decisions in Embryonic Stem Cells

The notion that the differentiated state of a cell population is determined simply by expression of specific marker genes is changing. In this work, the authors reveal that a pluripotent cell population comprises cells with temporal fluctuations in the expression of Nanog

Effect of pomegranate (Punica granatum L) peel powder meal dietary supplementation on antioxidant status and quality of breast meat in broilers

This study examined the antioxidant status and quality of breast meat in broiler birds fed diets supplemented with pomegranate peel powder meal (PPPM). During the 35-d feeding trial, broiler birds were fed six experimental diets: diet with 0% additives (negative control; NEGCON); diet with α-Tocopherol acetate at 200 g/tonne (positive control; POSCON); and four levels (2, 4, 6 and 8 g/kg) of PPPM, designated as PPPM2, PPPM4, PPPM6, and PPPM8. Breast muscle pH was determined 15mins and 24hrs postmortem. The breast muscles were then stored at 4 °C to determine shelf-life attributes (pH, colour, hue angle, and chroma) for 16 days. Meat from the 8 g/kg PPPM had the highest thawing loss, whereas cooking loss was lowest at 2 g/kg PPPM inclusion. The meat of birds fed 2 g/kg and 4 g/kg PPPM had the highest (P<0.05) ability to scavenge the ABTS [(2, 2-azinobis (3ethylbenzothiazoline-6 sulfonic acid))] radical cation (ABTS+), whereas, catalase activity was increased at 8 g/kg PPPM. The results obtained in this study indicate that 2 g/kg supplementation of pomegranate peel powder meal significantly improved the water-binding capacity of broiler breast meat, owing to the reduced cooking loss of the meat, and meat from the PPPM2 (2 g/kg) group had the highest ability to scavenge ABTS

The responses of an anaerobic microorganism, Yersinia intermedia MASE-LG-1 to individual and combined simulated Martian stresses

The limits of life of aerobic microorganisms are well understood, but the responses of anaerobic microorganisms to individual and combined extreme stressors are less well known. Motivated by an interest in understanding the survivability of anaerobic microorganisms under Martian conditions, we investigated the responses of a new isolate, Yersinia intermedia MASE-LG-1 to individual and combined stresses associated with the Martian surface. This organism belongs to an adaptable and persistent genus of anaerobic microorganisms found in many environments worldwide. The effects of desiccation, low pressure, ionizing radiation, varying temperature, osmotic pressure, and oxidizing chemical compounds were investigated. The strain showed a high tolerance to desiccation, with a decline of survivability by four orders of magnitude during a storage time of 85 days. Exposure to X-rays resulted in dose-dependent inactivation for exposure up to 600 Gy while applied doses above 750 Gy led to complete inactivation. The effects of the combination of desiccation and irradiation were additive and the survivability was influenced by the order in which they were imposed. Ionizing irradiation and subsequent desiccation was more deleterious than vice versa. By contrast, the presence of perchlorates was not found to significantly affect the survival of the Yersinia strain after ionizing radiation. These data show that the organism has the capacity to survive and grow in physical and chemical stresses, imposed individually or in combination that are associated with Martian environment. Eventually it lost its viability showing that many of the most adaptable anaerobic organisms on Earth would be killed on Mars today

Lolium multiflorum (ryegrass) diet modifies the productive response and enhances the meat of grass carp (Ctenopharyngodon idella Val.) with omega 3 fatty acid beneficial to human health

Registered in England & Wales No. 3099067Ctenopharyngodon idella (grass carp) is one of the most widely produced herbivorous species worldwide. However, forage feeding is not well studied in this species. This work aimed to evaluate the effect of feeding a diet based on Lolium multiflorum (ryegrass) on the growth performance and fatty acid composition in the meat of juvenile C. idella. For this purpose, juveniles were fed two different diets for 120 days: i) grains and their by-products (GD) and ii) Lolium multiflorum (PD). At 60 and 120 days of feeding, the weight gain, specific growth rate, feed conversion rate, protein efficiency, viscerosomatic index and condition factor were determined. The fatty acid profile and lipid nutritional indices of the meat were measured at 120 days. The GD group exhibited higher weight gain, specific growth rate and condition factor than the PD group. The GD group also had a higher conversion rate at the expense of greater fat content and elevated viscerosomatic index. The greater viscera development may explain the higher weight gain in the GD group. Healthy fatty acids, such as Alpha-linolenic, eicosapentaenoic, docosapentaenoic and docosahexaenoic fatty acids, were more elevated in the PD group while linoleic fatty acid (LA) was lower. Hence, LA induced a decrease in the n-6/n-3 ratio. In addition, hypercholesterolemic and atherogenetic saturated fatty acids were lower in the PD. This variation reduced the atherogenic, thrombogenicity and peroxidability indices. Therefore, better nutritional quality in the meat compensated for the lower growth of the fish on the PD.Ctenopharyngodon idella (carpa herbívora) es una de las especies herbívoras de mayor producción en todo el mundo. Sin embargo, la alimentación forrajera no está bien estudiada en esta especie. Este trabajo tuvo como objetivo evaluar el efecto de la alimentación con una dieta basada en Lolium multiflorum (ryegrass) sobre el comportamiento del crecimiento y la composición de ácidos grasos en la carne de juveniles de C. idella. Para ello, los juveniles fueron alimentados con dos dietas diferentes durante 120 días: i) granos y sus derivados (GD) y ii) Lolium multiflorum (PD). A los 60 y 120 días de alimentación se determinó la ganancia de peso, tasa específica de crecimiento, tasa de conversión alimenticia, eficiencia proteica, índice viscerosomático y factor de condición. El perfil de ácidos grasos y los índices nutricionales de lípidos de la carne se midieron a los 120 días. El grupo GD exhibió una mayor ganancia de peso, tasa de crecimiento específica y factor de condición que el grupo PD. El grupo GD también tuvo una mayor tasa de conversión a expensas de un mayor contenido de grasa y un índice viscerosomático elevado. El mayor desarrollo de vísceras puede explicar la mayor ganancia de peso en el grupo GD. Los ácidos grasos saludables, como los ácidos grasos alfa-linolénico, eicosapentaenoico, docosapentaenoico y docosahexaenoico, estaban más elevados en el grupo PD, mientras que el ácido graso linoleico (LA) estaba más bajo. Por lo tanto, LA indujo una disminución en la relación n-6/n-3. Además, los ácidos grasos saturados hipercolesterolémicos y aterogénicos fueron más bajos en la DP. Esta variación redujo los índices de aterogenia, trombogenicidad y peroxidabilidad. Por lo tanto, la mejor calidad nutricional de la carne compensó el menor crecimiento de los peces en la DP.Instituto de Investigación de Tecnología de Alimentos (ITA)Fil: Montenegro, Luciano Federico. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Investigación Tecnología de Alimentos; Argentina.Fil: Montenegro, Luciano Federico. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Montenegro, Luciano Federico. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; Argentina.Fil: García, Pilar Teresa. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Investigación Tecnología de Alimentos; Argentina.Fil: Descalzo, Adriana María. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Investigación Tecnología de Alimentos; Argentina.Fil: Perez, Carolina Daiana. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Investigación Tecnología de Alimentos; Argentina.Fil: Perez, Carolina Daiana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina