Synthesis of telomere-mimic carbocyclic 5'-nor oligodeoxynucleotides.
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Telomere-mimic S-ODNs have been synthesized and examined their effects on the proliferation of human tumor cell lines by XTT assay. Furthermore, the guanosine derivatives of carbocyclic 5'-nor nucleoside were synthesized. (+info)
Synthesis of carbocyclic nucleosides as potential antiviral agents.
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Treatment of 1-[(1'R,2'S,3'S,4'S)-4'-methanesulfonyl-2',3'-O- isopropylidenedioxycyclopentan-1'-yl]-1-H-uracil with LiN3 gave 1-[(1'R,2'S,3'R)-2',3'-O-isopropylidenedioxy-4'- cyclopenten-1'-yl]-1-H-uracil. When KOBut was added instead of LiN3, 1-[(1'R,2'S)-2',3'-O- isopropylidenedioxy-3'-cyclopenten-1'-yl]-1-H-uracil was produced. An analogous treatment of the methanesulfonyl derivative of thymine was also carried out. (+info)
Synthesis of carbocyclic analogues of 4'-ethynyl- and 4'-cyano-d4T.
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Synthesis of carbocyclic analogues of 4'-ethynyl and cyano-d4T (4 and 5) was investigated. The ethynyl or cyano group was constructed by conversion of the ester function of key intermediate 13. The carbocyclic unit 12 was prepared from readily available beta-keto ester 6. (+info)
Carbocyclic analogues of lexitropsin--DNA affinity and endonuclease inhibition.
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A DNA-binding affinity and the effect on restriction enzymes activity of seven carbocyclic mono- and bis-lexitropsins and two analogues of pentamidine with unsubstituted N-terminal amine group were investigated. DNA association constants (Kapp) show that DNA affinity of mono-compounds is much weaker than netropsin and distamycin. Bis-analogues of netropsin bind DNA more strongly than mono-ligands, but without sequence-selectivity. Only pentamidine derivatives reveal preference to AT-rich sequence. The studied compounds can inhibit catalytical action of endonucleases recognizing sequence of four AT base pairs following one another. (+info)
Lichen photobionts show tolerance against lichen acids produced by lichen mycobionts.
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In order to determine the allelopathic nature of lichen acids produced by lichen mycobionts, we compared lichen photobionts with other photosynthetic organisms in terms of inhibition of photosynthetic electron transport around photosystem II (PSII) by representative lichen acids. Whereas at the thylakoid level we found no clear difference in tolerance against lichen acids between lichen photobionts and other species, at the cellular level lichen photobionts showed strong tolerance as compared with other species. These findings suggest the presence of a lichen acid-specific exclusion or detoxification mechanism in lichen photobiont cells. (+info)
Clinical applications of urinary organic acids. Part 2. Dysbiosis markers.
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Part 1 of this series focused on urinary organic acids as markers of detoxification; part 2 focuses on dysbiosis markers. Intestinal microbial growth is accompanied by the release of products of their metabolism that may be absorbed and excreted in urine. Several organic acids are known to be specific products of bacterial metabolic action on dietary polyphenols or unassimilated amino acids or carbohydrates. Associated gastrointestinal or neurological symptoms may result from irritation of the intestinal mucosa or systemic distribution of absorbed neurotoxic products. Detection of abnormally elevated levels of these products is a useful diagnostic tool for patients with gastrointestinal or toxicological symptoms. Test profiles of urinary organic acids associated with microbial overgrowth can include benzoate, hippurate, phenylacetate, phenylpropionate, cresol, hydroxybenzoate, hydroxyphenylacetate, hydroxyphenylpropionate and 3,4-dihydroxyphenylpropionate, indican, tricarballylate, D-lactate, and D-arabinitol. Effective treatments for the associated microbial overgrowths may be directed at reducing microbial populations, introducing favorable microbes, and restoring intestinal mucosal integrity. (+info)
Synthesis, characterization and activity evaluation of matrinic acid derivatives as potential antiproliferative agents.
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Synthetic analogues of netropsin and distamycin--synthesis of a new pyridine and carbocyclic analogues of the pyrrolecarboxamide antitumour antibiotics.
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A new series of pyridine-containing analogues III-XXII of distamycin A and netrop sin was investigated by the molecular mechanics technique and molecular modelling. A pyridine analogue of netropsin (VII) is described, the first compound based on molecular studies, and two carbocyclic analogues of distamycin A with an N-terminal chloro- or bromoacetyl group (VIa, VIIa) were synthesized, as well as carbocyclic analogues of netropsin (VIIIb, Xb), potential carriers of alkylating elements. The potential use of VIa, VII, VIIa, VIIIb and Xb as carriers to place into the minor groove of DNA chemical groups capable of modifying DNA, is discussed. (+info)