The discovery that peptide nucleic acids (PNA) mimic DNA and RNA by forming complementary duplex structures following Watson--Crick base pairing rules opens fields in biochemistry, diagnostics, and ...medicine for exploration. Progress requires the development of modified PNA duplexes having unique and well defined properties. We find that anthraquinone groups bound to internal positions of a PNA oligomer intercalate in the PNA-DNA hybrid. Their irradiation with near-UV light leads to electron transfer and oxidative damage at remote GG doublets on the complementary DNA strand. This behavior mimics that observed in related DNA duplexes and provides the first evidence for long range electron (hole) transport in PNA-DNA hybrid. Analysis of the mechanism for electron transport supports hole hopping.
The locked nucleic acid (LNA) chemistry brings truly stunning affinity and high biostability to the world of nucleic acids. In turn, these features enable the design of shorter-than-usual oligos that ...exhibit unprecedented potency, good specificity, high biostability, good biodistribution, and low toxicity. Such LNA-oligos have been termed RNA antagonists to signal the strong belief that they will transform antisense therapy into a robust drug platform. It is further expected that this new class of drugs will be compatible with less frequent and more convenient dosing regimens than those currently employed with first generation DNA/sub PS/-oligos (DNA-oligos based on phosphorothioate chemistry). For instance, their enhanced biostability may well enable weekly, or even biweekly, dosing. Likewise, the apparent absence of acute toxicities associated with therapeutically sized DNA/sub PS/-oligos may well enable RNA antagonists to be administered by direct bolus injection by healthcare professionals or even by the patients themselves.
Four non‐pigment‐producing isolates and two pigment‐producing isolates of Aeromonas salmonicida sp. salmonicida were isolated from the head‐kidney of diseased farmed Atlantic salmon, Salmo salar L. ...The cultural, morphological and biochemical features of the isolates were compared with those of reference strains. Injection and cohabitation experiments were performed. The only difference between the non‐pigment‐producing isolates and the pigment producing reference strains of A. salmonicida ssp. salmonicida was the inability of the former to produce pigment. In the injection experiments, the investigated non‐pigment‐producing isolate produced a significantly higher mortality compared with the mortality caused by the reference strain, whereas no difference in mortality was detected in the cohabitation experiments.
A series of partially self-complementary peptide nucleic acid (PNA) oligomers was prepared. Examination of their melting behavior, circular dichroism spectra, and fluorescence properties reveals that ...these PNA oligomers exist as stem-loop (“hairpin”) structures. Fluorescence is readily observed in hairpins containing a covalently linked, emissive acridine derivative which is, at least partially, intercalated in the duplex region of the PNA hairpin. The acridine fluorescence is quenched when an anthraquinone derivative is covalently attached to the PNA so that it is bound near the acridine in the hairpin structure. Acridine fluorescence is restored in hairpins containing both the anthraquinone and the acridine by increasing the temperature and melting the structure to its linear form or by opening the hairpin through formation of a hybrid duplex with complementary DNA. The latter process may form the basis for development of selective and sensitive DNA assays.
This study was designed to compare the complete blood count values of opioid users (N = 61) and healthy subjects (N = 61), particularly monocyte-to-lymphocyte ratio (MLR) and platelet-to-lymphocyte ...ratio (PLR). PLR, MLR, and percentage of monocyte (MONO%) were significantly lower in opioid use disorder (OUD) group (P = 0.012, P = 0.005, P = 0.000). The area under the ROC curve of MLR and PLR levels for OUD was 0.349 and 0.368. MONO% correlated with substance use duration. Measurements like lymphocyte-related ratios and MONO% in opioid use can be important in substance monitoring, detection, and differentiation of acute and chronic conditions.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The sequence GCGCGCGCGC contains three overlapping, mutually exclusive, BssHII restriction sites, each corresponding to one of the three different reading frames. When inserted into a plasmid and ...digested with BssHII, the three sites in this sequence are cleaved at an approximate ratio of 2:1:2. Consequently, this system can be used to simplify in vitro in frame fusions to involve a single plasmid. We have constructed such a plasmid and used it to select an open reading frame in a 1.6 kb cDNA fragment.
A bis-peptide nucleic acid (PNA)-anthraquinone imide (AQI) conjugate has been synthesized and shown to form strand invasion complexes with a duplex DNA target. The two arms of the bis-PNA each ...consist of five consecutive thymine residues and are linked by a flexible, hydrophilic spacer. Probing with potassium permanganate reveals that the bis-PNA complexes to duplex DNA at A5·T5 sites with local displacement of the T5 DNA strand. The 5 bp sequence targeted by the PNA is the shortest strand invasion complex reported to date. Irradiation of the strand invasion complex results in asymmetric cleavage of the displaced strand, with more efficient cleavage at the 3′-end of the loop. This result indicates that the bis-PNA binds to the DNA such that the C-terminal T5 sequence forms the strand invasion complex, leaving the N-terminal T5 sequence to bind by triplex formation, thereby placing the AQI closer to the 3′-end of the displaced strand, consistent with the observed photocleavage pattern. The ability of the PNA to directly report its binding site by photoinduced cleavage could have significant utility in mapping the secondary and tertiary structure of nucleic acids.
Peptide nucleic acids (PNA) mimic DNA and RNA by forming complementary duplex structures following Watson-Crick base pairing. A set of reporter compounds that bind to DNA by intercalation are known, ...but these compounds do not intercalate in PNA/DNA hybrid duplexes. Analysis of the hybrid PNA duplexes requires development of reporter compounds that probe their chemical and physical properties. We prepared a series of anthraquinone (AQ) derivatives that are linked to internal positions of a PNA oligomer. These are the first non-nucleobase functional groups that have been incorporated into a PNA. The resulting PNA(AQ) conjugates form stable hybrids with complementary DNA oligomers. We find that when the AQ groups are covalently bound to PNA that they stabilize the hybrid duplex and are, at least partially, intercalated.
The specific reaction of potassium permanganate with thymine in single-stranded DNA was employed to analyze thymine 2+2 dimer repair in DNA and in DNA/peptide nucleic acid hybrid duplexes. This ...simple and highly sensitive chemical assay is convenient for monitoring repair of thymine dimers in oligonucleotides.
PDF
