Crystallization of Organic Compounds in Reversed Micelles. I. Solubilization of Amino Acids in Water−Isooctane−AOT Microemulsions

Langmuir ◽  
2000 ◽  
Vol 16 (26) ◽  
pp. 9996-10004 ◽  
Author(s):  
Junko Yano ◽  
Helga Füredi-Milhofer ◽  
Ellen Wachtel ◽  
Nissim Garti
Keyword(s):  
Amino Acids ◽  
Organic Compounds ◽  
Reversed Micelles

Crystallization of Organic Compounds in Reversed Micelles. III. Solubilization of Aspartame

Langmuir ◽  
2003 ◽  
Vol 19 (15) ◽  
pp. 5984-5990 ◽  
Author(s):  
Helga Füredi-Milhofer ◽  
Alexey Kamishny ◽  
Junko Yano ◽  
Abraham Aserin ◽  
Nissim Garti
Keyword(s):  
Organic Compounds ◽  
Reversed Micelles

Search for molecular biosignatures on Mars: laboratory simulations of UV irradiation of molecule-mineral complexes

2021 ◽  
Author(s):  
Teresa Fornaro ◽  
Giovanni Poggiali ◽  
Maria Angela Corazzi ◽  
Cristina Garcia ◽  
Giulia Dimitri ◽  
...  
Keyword(s):  
Amino Acids ◽  
Organic Compounds ◽  
Uv Irradiation ◽  
Organic Molecules ◽  
Spectroscopic Characterization ◽  
Sample Return ◽  
Laboratory Simulations ◽  
Prebiotic Molecules

<div> </div> <p><strong>Abstract</strong></p> <p>We present laboratory activities of preparation, characterization, and UV irradiation processing of Mars soil analogues, which are key to support both in situ exploration and sample return missions devoted to detection of molecular biosignatures on Mars.</p> <p>In detail we prepared analog mineral samples relevant to the landing sites of past, present and future Mars exploration missions, such as Gale Crater, Jezero Crater, and Oxia Planum. We doped these samples with a large variety of organic molecules (both biotic and prebiotic molecules) like amino acids, nucleotides, monosaccharides, aldehydes, lipids. We investigated molecular photostability under UV irradiation by monitoring in situ possible modifications of infrared spectroscopic features. These investigations provide pivotal information for ground analysis carried out by rovers on Mars.</p> <p><strong>Introduction</strong></p> <p>Laboratory simulations of Mars are key to support the scientific activity and technology development of life detection instruments on board present and upcoming rover missions such as Mars2020 Perseverance [1] and ExoMars2022 Rosalind Franklin [2]. Studies about the stability of organic molecules in a Martian-like environment allow us to explore the conditions for the preservation of molecular biosignatures and develop models for their degradation in the Martian geological record. A systematic study of the effects of UV radiation on a variety of molecule-mineral complexes mimicking Martian soil can be key for the selection of the most interesting samples to analyse in situ or/and collect for sample return. Testing the sensitivity of different techniques for detection of the diagnostic features of molecular biosignatures embedded into mineral matrices as a function of the molecular concentration helps the choice, design and operation of flight instruments, as well as the interpretation of data collected on the ground during mission operative periods.</p> <p><strong>Methods</strong></p> <p>Experimental analyses were conducted in the Astrobiology Laboratory at INAF-Astrophysical Observatory of Arcetri (Firenze, Italy). Laboratory activities pertain to: (i) synthesis of Mars soil analogues doped with organic compounds that are considered potential molecular biosignatures; (ii) UV-irradiation processing of the Mars soil analogues under Martian-like conditions; and (iii) spectroscopic characterization of the Mars soil analogues.</p> <p><strong>Results</strong></p> <p>Such studies have shown to be very informative in identifying mineral deposits most suitable for preservation of organic compounds, while highlighting the complementarity of different techniques for biomarkers detection, which is critical for ensuring the success of space missions devoted to the search for signs of life on Mars.</p> <p>We will present a series of laboratory results on molecular degradation caused by UV on Mars and possible application to detection of organics by Martian rovers [3,4,5,6]. In detail, we investigated the photostability of several amino acids like glycine, alanine, methionine, valine, tryptophan, phenylalanine, glutamic acid, prebiotic molecules like urea, deoxyribose and glycolaldehyde, and biomarkers like nucleotides and phytane adsorbed on relevant Martian analogs. We monitored the degradation of these molecule-mineral complexes through in situ spectroscopic analysis, investigating the reflectance properties of the samples in the NIR/MIR spectral region. Such spectroscopic characterization of molecular alteration products provides support for two upcoming robotic missions to Mars that will employ NIR spectroscopy to look for molecular biosignatures, through the instruments SuperCam on board Mars 2020, ISEM, Ma_MISS and MicrOmega on board ExoMars 2022.</p> <p><strong>Acknowledgements</strong></p> <p>This research was supported by the Italian Space Agency (ASI) grant agreement ExoMars n. 2017-48-H.0.</p> <p><strong>References</strong></p> <p>[1] Farley K. A. et al. (2020) Space Sci. Rev. 216, 142.</p> <p>[2] Vago, J. L. et al. (2017) Astrobiology 6, 309–347.</p> <p>[3] Fornaro T. et al. (2013) Icarus 226, 1068–1085.</p> <p>[4] Fornaro T. et al. (2018) Icarus 313, 38-60.</p> <p>[5] Fornaro T. et al. (2020) Front. Astron. Space Sci. 7:539289.</p> <p>[6] Poggiali G. et al. (2020) Front. Astron. Space Sci. 7:18.</p>

The excystation of Entamoeba histolytica without bacteria in microcultures

Parasitology ◽  
1950 ◽  
Vol 40 (3-4) ◽  
pp. 338-342 ◽  
Author(s):  
Charles W. Rees ◽  
Lucy V. Reardon ◽  
Ida Louise Bartgis
Keyword(s):  
Carbon Dioxide ◽  
Amino Acids ◽  
Folic Acid ◽  
Vitamin C ◽  
Trypanosoma Cruzi ◽  
Organic Compounds ◽  
Entamoeba Histolytica ◽  
Plasmodium Knowlesi ◽  
Sodium Potassium ◽  
Potassium Magnesium

1. Formulae developed by Anfinsen et al. (1946) for a medium used in the cultivation of Plasmodium knowlesi were used for media in which excystation of Entamoeba histolytica without bacteria was investigated.2. The following media were used: (i) an inorganic fluid containing carbon dioxide and chlorides, phosphates, and bicarbonates, of sodium, potassium, magnesium, and calcium; (ii) an inorganic fluid of chlorides and phosphates of the above metals without bicarbonates; (iii) the same respective fluids plus glucose, and (iv) the same plus enrichments with B vitamins, cocarboxylase, vitamin C, purines, pyrimidines, folic acid, glucosamine, cholesterol, and amino-acids. The oxygen content of all media was lowered either by cysteine or glutathione.3. Some excystation occurred in all media, the percentages were lowest in the inorganic fluid without bicarbonates, highest in fluid with bicarbonates plus all of the listed organic compounds, and intermediate in the inorganic bicarbonate fluid plus glucose. Amino-acids were not required for good percentages of excystation.4. Excystation occurred when cysts were isolated in medium with Trypanosoma cruzi.5. The data show that organic compounds in the medium are necessary for high percentages of excystation.

Effect of easily biodegradable organic compounds on bacterial growth in a bench-scale drinking water distribution system

2000 ◽  
Vol 27 (3) ◽  
pp. 412-420 ◽  
Author(s):  
Graham A Gagnon ◽  
Robin M Slawson ◽  
Peter M Huck
Keyword(s):  
Amino Acids ◽  
Drinking Water ◽  
Organic Compounds ◽  
Free Amino ◽  
Distribution Systems ◽  
Water Distribution ◽  
P Value ◽  
Drinking Water Distribution Systems ◽  
Loading Rates ◽  
Drinking Water Distribution

Many engineered (e.g., disinfectant residual concentration) and environmental (e.g., temperature) factors influence bacterial regrowth in drinking water distribution systems. This paper examines the effect of nutrients, specifically biodegradable organic matter (BOM) composition, BOM concentration, and hydraulic retention time on bacterial growth in an annular reactor (AR). Drinking water that had an alkalinity of 300 mg/L as CaCO3and a free chlorine residual of approximately 0.2 mg/L was used as process water in the ARs. Prior to entering the ARs, the water was filtered through granular activated carbon (GAC) to remove background chlorine and background organic matter. A cocktail of easily biodegradable organic compounds consisting of carboxylic acids, aldehydes, and free amino acids were spiked into the ARs as the primary carbon source. It was found that the influent BOM concentration (p value = 0.013) and the presence of free amino acids in the BOM cocktail (p value = 0.009) significantly increased the number of viable culturable cells in the biofilm, as measured by heterotrophic plate counts (HPCs). The interaction between the BOM concentration and the presence of amino acids also significantly increased the number of biofilm HPCs (p value = 0.021). Alternatively, the BOM concentration and the amino acid fraction did not affect the number of bulk (i.e., suspended) bacteria. The number of biofilm HPCs in the reactor was approximately 10 times greater than the number of bulk HPCs at high influent BOM concentrations and low retention times (i.e., high BOM loading rates). At low loading rates, the ratio of number of biofilm to bulk cells was less than 2. Consequently, it was deduced that the BOM was utilized predominately by the biofilm cells. This indicates that removal of easily biodegradable organic compounds is an important factor for controlling biofilm growth in distribution systems.Key words: drinking water, distribution systems, biofilm, annular reactor, regrowth.

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