In this study the possibility to detect biomarkers in experimentally prepared evaporitic matrices using a portable Raman instrument was estimated. Testing of the instrument was carried-out under the Alpine conditions outdoors at a low ambient temperature of -10 °C and at an altitude of 2860 m (Pitztal, Austria). Amino acids glycine and l-alanine, nucleo bases thymine and adenine, and metabolite urea were the organics mixed with gypsum powder. In this step it was shown that portable Raman spectroscopic instrumentation is capable of detecting biomarkers in complex samples in a host geological matrix. Such detection is possible even when the laser beam was focussed through the gypsum crystals 3-9 mm thick. For exobiology areas, this is an important fact, because life and/or related biomolecules are likely to be found in cavities under the surface of partially transparent evaporitic minerals that provide them a shelter from the hostile surrounding environment. For influencing the intensity of Raman bands the thickness of covering crystals is not as important as is the actual concentration of the biomarkers. This work and similar experiments serve for better evaluation of Raman spectroscopy as a method for future planetary exploration mission adoption.
- MeSH
- adenin analýza MeSH
- alanin MeSH
- biologické markery analýza MeSH
- glycin analýza MeSH
- krystalizace MeSH
- močovina analýza MeSH
- prášky, zásypy, pudry analýza MeSH
- Ramanova spektroskopie přístrojové vybavení MeSH
- síran vápenatý chemie MeSH
- thymin analýza MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- adenin MeSH
- alanin MeSH
- biologické markery MeSH
- glycin MeSH
- močovina MeSH
- prášky, zásypy, pudry MeSH
- síran vápenatý MeSH
- thymin MeSH
A complex OsO(4), 2,2'-bipyridine (Os,bipy), has been used for electroactive labeling of biopolymers as well as for probing of nucleic acids and protein structure and interactions. In DNA, Os,bipy forms electrochemically active adducts with pyrimidine nucleobases, exhibiting highly selective modification of thymine residues in single-stranded DNA. Here, we show that modification of rare thymine residues (one thymine among several tens of unreactive purine bases) can easily be detected by means of a simple ex situ voltammetric analysis using carbon electrodes. Based on this remarkable sensitivity of detection, Os,bipy has been used as an electroactive probe for unpaired and/or mismatched thymine residues within DNA heteroduplexes. Site-specific chemical modification of the DNA with the Os,bipy has allowed a clear distinction between perfectly base-paired DNA homoduplexes and mismatched heteroduplexes, as well as discrimination among heteroduplexes containing one or two mispaired thymines, a single thymine insertion, or combination of a mispair and an insertion.
- MeSH
- DNA sondy * MeSH
- DNA chemie MeSH
- elektrochemie metody MeSH
- heteroduplexy nukleové kyseliny chemie MeSH
- jednonukleotidový polymorfismus * MeSH
- osmium chemie MeSH
- sekvence nukleotidů MeSH
- thymin analýza MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- DNA sondy * MeSH
- DNA MeSH
- heteroduplexy nukleové kyseliny MeSH
- osmium MeSH
- thymin MeSH
We analyzed occurrences of bases in 20,352 introns, exons of 25,574 protein-coding genes, and among the three codon positions in the protein-coding sequences. The nucleotide sequences originated from the whole spectrum of organisms from bacteria to primates. The analysis revealed the following: (1) In most exons, adenine dominates over thymine. In other words, adenine and thymine are distributed in an asymmetric way between the exon and the complementary strand, and the coding sequence is mostly located in the adenine-rich strand. (2) Thymine dominates over adenine not only in the strand complementary to the exon but also in introns. (3) A general bias is further revealed in the distribution of adenine and thymine among the three codon positions in the exons, where adenine dominates over thymine in the second and mainly the first codon position while the reverse holds in the third codon position. The product (A1/T1)x(A2/T2)x(T3/A3) is smaller than one in only a few analyzed genes.
- MeSH
- adenin analýza MeSH
- DNA chemie genetika MeSH
- eukaryotické buňky MeSH
- exony genetika MeSH
- genetický kód MeSH
- genom MeSH
- geny genetika MeSH
- introny genetika MeSH
- nukleové kyseliny chemie genetika MeSH
- prokaryotické buňky MeSH
- RNA chemie genetika MeSH
- thymin analýza MeSH
- zastoupení bazí * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
- Názvy látek
- adenin MeSH
- DNA MeSH
- nukleové kyseliny MeSH
- RNA MeSH
- thymin MeSH
Both the post-replication and the excision repair mechanism participate in the induction of Trp+ revertants in Escherichia coli B/r Hcr+ thy trp after a UV-irradiation. At low radiation doses (surviving cell fraction greater than 10(-1) most Trp+ reversions are due to post-replication repair mechanism while at high doses (surviving cell fraction less than 10(-1)) the Trp+ reversions arise probably as the result of an inaccurate excision repair. The absolute accuracy of repair processes decreases with increasing radiation dose.
- MeSH
- DNA bakterií analýza metabolismus účinky záření MeSH
- Escherichia coli analýza metabolismus účinky záření MeSH
- mutace MeSH
- oprava DNA * MeSH
- radiační účinky MeSH
- thymin analýza MeSH
- tryptofan biosyntéza MeSH
- ultrafialové záření * MeSH
- vztah dávky záření a odpovědi MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- DNA bakterií MeSH
- thymin MeSH
- tryptofan MeSH
