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Wyświetlanie 1-5 z 5
Tytuł:
Wykorzystanie reakcji 1,3-dipolarnej cykloaddycji Huisgena do modyfikacji nukleozydów i ligonukleotydów
An application of the Huisgen 1,3-dipolar cycloaddition to modify nukleosides and oligonucleotides
Autorzy:
Radzikowska, E.
Powiązania:
https://bibliotekanauki.pl/articles/171872.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
1,3-dipolarna cykloaddycja
analogi nukleozydów
chemia click
synteza modyfikowanych oligonukleotydów
1,2,3-triazole
biokoniugaty
1,3-dipolar cycloaddition
analogues of nucleosides
click chemistry
synthesis of modified oligonucleotide
bioconjugates
Opis:
The 1,3-dipolar cycloaddition reaction between azides and terminal alkynes, known as the Huisgen reaction, constitutes a powerful tool for the synthesis of versatile molecules containing carbon – heteroatom bond. The use of a copper(I) salt in this reaction allowed Sharpless to develop the concept of „click chemistry” [1]. This strategy is based on reactions between small units characterized by mild reaction conditions, versatility, high yields and stereospecificity. The chemistry of nucleic acids and nucleoside analogues is undergoing rapid developments and numerous compounds from these classes of compounds are used in medicinal treatment. Analogues of nucleoside constitute a class of drugs that possesses either anticancer or/and antiviral activity (against HIV, HSV, VZV or HCV viruses) [3]. Many modified oligonucleotides show biological activity. As potential drugs oligonucleotides are employed in antisense, antigen and aptamer strategies. An antisense therapeutic agent acts on the pathogenic mRNA causing inactivation of the target whereas an antigen agent acts on DNA and aptamer on unwanted protein. It is not surprising that number of research groups are trying to join the concept of click chemistry with nucleic acids chemistry. In this way, it is possible to obtain new molecules like base- or sugar-modified nucleosides, nucleosides, bioconjugates and olignucleotides. The copper-catalyzed 1,3-dipolar cycloaddition CuAAC allows to functionalize DNA, for example by labelling it through attaching small molecules to DNA. Two general strategies have been developed for this purpose: presynthetic and postsynthetic labelling. In the presynthetic method nucleotide monomers are labelled before DNA synthesis and purification. In the postsynthetic strategy DNA containing small reactive groups is synthesized first and then it is conjugated with the desired molecules. CuAAC is also a convenient method for the synthesis of modified oligonucleotides in which phosphodiester linkage is replaced by 1,2,3- -triazole or for a solid phase synthesis. Such molecules appear to be useful in medicine, molecular diagnostic (e.g. fluorescent dyes) or mechanistic molecular model in the future.
Źródło:
Wiadomości Chemiczne; 2011, 65, 3-4; 207-234
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modyfikowane oligodeoksyrybonukleotydy zawierające w wiązaniu internukleotydowym w pozycji mostkowej atom azotu
Modified oligodeoxyribonucleotides containing nitrogen at a bridging position of an internucleotide bond
Autorzy:
Radzikowska, E.
Powiązania:
https://bibliotekanauki.pl/articles/172442.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
analogi kwasów nukleinowych
modyfikacje wiązania internukleotydowego
oligodeoksyrybonukleozydo-(P3’→N5’)amidofosforany
oligodeoksyrybonukleozydo-(N3’→P5’)amido(tio)fosforany
strategia antysensowa
telomeraza
reakcja Athertona-Todda
nucleic acids analogues internucleotide linkage modifications
oligodeoxyribonucleoside-(P3’→N5’)phosphoramidates
oligodeoxyribonucleoside-
(N3’→P5’)(thio)phosphoramidates antisense strategy
telomerase
Atherton-Todd reaction
Opis:
Synthetic oligonucleotides (ONs) constitute an important class of compounds which exhibit biological activity. As potential drugs ONs are employed in the antisense strategy [1]. The antisense therapeutic agent acts on the pathogenic mRNA causing inactivation of the target. Ideal antisense agent should be resistant to exo and/or endonucleases, have a suitable pharmacological and pharmacokinetic profile and high affinity for the target. To improve some properties of antisense oligonucleotides plethora of chemical modifications introduced within both sugar unit and internucleotides linkage were investigated. Among numerous ONs modified in internucleotide phosphodiester bond, one of the most interesting are oligonucleotide phosphoramidates (NP-oligos) in which one of the bridging oxygens is replaced by nitrogen atom (at 3’ or 5’ position). Hence, two classes of compounds are formed: oligonucleotide-(N5’→P3’)phosphoramidates and oligonucleotide(N3’→P5’)-phosphoramidates. These compounds, similar to native DNA and RNA, possess an achiral phosphorous atom and all internucleotides bonds are negatively charged. Additionally, NP-oligo shows good resistance to nucleolytic degradation and can bind to the target DNA or RNA with high affinity [12]. In literature several synthetic strategies concerning both (N5’→P3’) and (N3’→P5’) NP-oligos have been described. Some of them allowed to obtain only corresponding dimers. In the light of recent discoveries the most promising candidates for therapeutic and diagnostic applications are oligonucleotide-(N3’→P5’)thiophosphoramidates. Gryaznov et al. have found that such compounds can act as potent and selective telomerase inhibitors [29]. Human telomerase (TA) is a reverse transcriptase ribonucleoprotein that synthesizes de novo d-(TTAGGG)n repeats at chromosomal DNA ends. Whereas activity of this enzyme is observed in ~85% of all human tumors, most of normal somatic cells either lack TA activity or express it only at low levels. For these reasons TA constitute an attractive and nearly universal anticancer target for rational drug development.
Źródło:
Wiadomości Chemiczne; 2013, 67, 11-12; 1003-1025
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synteza modyfikowanych oligonukleotydów zawierających stereozdefiniowane internukleotydowe wiązania tiofosforanowe
Synthesis of modified oligonucleotides containing stereodefined internucleotide phosphorothioate bonds
Autorzy:
Radzikowska, E.
Kaczmarek, R.
Baraniak, J.
Powiązania:
https://bibliotekanauki.pl/articles/172219.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
oligonukleozydotiofosforany
oligonukleotydy antysensowe
synteza modyfikowanych oligonukleotydów
synteza stereospecyficzna
oligo(deoxy)ribonucleoside phosphorothioates
antisense oligonucleotides
synthesis of modified oligonucleotide
stereospecific synthesis
Opis:
Synthetic oligonucleotides constitute an important class of compounds which can exhibit biological activity. As potential drugs they could be employed in antisense strategy by acting on the pathogenic mRNA, causing inactivation of the target molecules during the translation process [1]. Ideal antisense agent (ASO) should be resistant to exo and/or endonucleases, exhibit a suitable pharmacological and pharmacokinetic profile and exhibits high binding affinity towards the target mRNA. To improve some properties of the ASO plethora of the chemical modifications introduced within the nucleobase, sugar unit and internucleotide linkage are investigated [3]. Among them, phosphorothioate oligonucleotides (PS-oligo), created by replacing one of the nonbridging oxygen atoms with a sulfur atom, are the major representatives of DNA analogs. PS-oligo display several attractive features like nuclease resistance, activation of RNase H, and good pharmacokinetic properties [1]. Replacement of one of two nonbridging oxygens at phosphorus by sulfur induces asymmetry at the phosphorus atom. Hence, the synthesized oligo(nucleoside phosphorothioate) is a mixture of 2n diastereomers (where n is the number of internucleotide phosphorothioate functions). Therefore the actual biological activity of the P-chiral oligonucleotide analogues, (e.g., interactions with proteins or nucleic acids) may depend on stereochemical factors [7]. One has to keep in mind that the phosphoramidite [5] and H-phosphonate [32] methodologies (commonly used to prepare PS-oligo) are nonstereospecific and give a mixture of 2n diastereomers. Thus, various methods have been elaborated to synthesize these P-chiral oligonucleotide analogs in a stereocontrolled manner [15, 17], among them the oxathiaphospholane method developed by Stec et al. [18], the method utilizing nucleoside 3’-O-(3-N-acyl)oxazaphospholidine derivatives as monomer units [19], and the method based on a stereoselective synthesis of nucleoside 3’-O-oxazaphospholidine monomers [21, 22] are the most significant.
Źródło:
Wiadomości Chemiczne; 2015, 69, 11-12; 957-981
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ultrastructural haemomicrocircular channel links of rat testicle in streptozotocin-induced diabetes
Autorzy:
Kryvko, Y.
Mateshuk-Vatseba, L.
Savka, I.
Luszczewska-Sierakowska, I.
Wawrzyniak, A.
Radzikowska, E.
Maciejewski, R.
Powiązania:
https://bibliotekanauki.pl/articles/3590.pdf
Data publikacji:
2014
Wydawca:
Instytut Medycyny Wsi
Tematy:
ultrastructure
hemomicrocircular channel
tissue
seminal duct
arteriole
rat
testicle
streptozotocin
diabetes
Opis:
Abstract The first changes in rat testicle haemomicrocircular channel links ultrastructural arrangement are noticed already in a 2-week run of streptozotocin-induced diabetes mellitus, and accumulate throughout next periods of the experiment. Angiopathy is a trigger mechanism for diabetic development of testicle structural changes. This finding is a basis for further morphologist and clinicist surveys for the purpose of new diabetic testicle pathology diagnostics, prevention, and elaboration of treatment techniques.
Źródło:
Journal of Pre-Clinical and Clinical Research; 2014, 08, 2
1898-2395
Pojawia się w:
Journal of Pre-Clinical and Clinical Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estrogen-induced hepatotoxicity in rats
Autorzy:
Radzikowska, E.
Luszczewska-Sierakowska, I.
Madej, B.
Burdan, F.
Mandziuk, S.
Sokoluk, M.
Dabrowski, A.
Maciejewski, R.
Powiązania:
https://bibliotekanauki.pl/articles/2999.pdf
Data publikacji:
2012
Wydawca:
Instytut Medycyny Wsi
Źródło:
Journal of Pre-Clinical and Clinical Research; 2012, 06, 1
1898-2395
Pojawia się w:
Journal of Pre-Clinical and Clinical Research
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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