Arylethynyltrifluoroborate Dienophiles for on Demand Activation of IEDDA Reactions.

Strained alkenes and alkynes are the predominant dienophiles used in inverse electron demand Diels-Alder (IEDDA) reactions. However, their instability, cross-reactivity, and accessibility are problematic. Unstrained dienophiles, although physiologically stable and synthetically accessible, react with tetrazines significantly slower relative to strained variants.

Flow cytometric determination of cell cycle progression via direct labeling of replicated DNA.

The reported method allows for a simple and rapid monitoring of DNA replication and cell cycle progression in eukaryotic cells in vitro. The DNA of replicating cells is labeled by incorporation of a metabolically-active fluorescent (Cy3) deoxyuridine triphosphate derivative, which is delivered into the cells by a synthetic transporter (SNTT1). The cells are then fixed, stained with DAPI and analyzed by flow cytometry.

Brightly Fluorescent 2'-Deoxyribonucleoside Triphosphates Bearing Methylated Bodipy Fluorophore for in Cellulo Incorporation to DNA, Imaging, and Flow Cytometry.

Synthesis of cytosine, uracil, and 7-deazaadenine 2'-deoxyribonucleosides and triphosphates (dNTPs) bearing hexamethylated phenyl-bodipy fluorophore attached at position 5 of pyrimidines or at position 7 of 7-deazapurine was developed. All the title labeled nucleosides and dNTPs displayed bright green fluorescence with very high quantum yields. The modified dNTPs were good substrates to diverse DNA polymerases and were used for in vitro enzymatic synthesis of labeled DNA by primer extension or PCR.

Transport of Nucleoside Triphosphates into Cells by Artificial Molecular Transporters.

Chemically modified nucleoside triphosphates (NTPs) are widely exploited as unnatural metabolites in chemical biology and medicinal chemistry. Because anionic NTPs do not permeate cell membranes, their corresponding neutral precursors are employed in cell-based assays. These precursors become active metabolites after enzymatic conversion, which often proceeds insufficiently.

Occurrence of ticks (Parasitiformes, Ixodida, Amblyommidae) on the skin of African buffalo Syncerus caffer (Sparrman, 1779) (Mammalia, Artiodactyla) originating from an area of the Republic of South Africa.

Most ticks of the genus Amblyomma and Rhipicephalus are typical ectoparasites of bovine. However, information about survival in different environmental conditions or coexistence of different species is lacking. Amblyomma hebraeum Koch, 1844, Rhipicephalus appendiculatus Neumann, 1901 and R.

Reactivity of 9-aminoacridine drug quinacrine with glutathione limits its antiprion activity.

Quinacrine-the drug based on 9-aminoacridine-failed in clinical trials for prion diseases, whereas it was active in in vitro studies. We hypothesize that aromatic nucleophilic substitution at C9 could be contributing factor responsible for this failure because of the transfer of acridine moiety from quinacrine to abundant glutathione. Here, we described the semi-large-scale synthesis of the acridinylated glutathione and the consequences of its formation on biological and biophysical activities.

Structural revisions of small molecules reported to cross-link G-quadruplex DNA in vivo reveal a repetitive assignment error in the literature.

Two molecules of mistaken identity are addressed. Uncovering these assignment errors led us to formulate more general guidelines about additional misassignments in cases of published bis-imines derived from 1,2-phenylenediamine and hydroxybenzaldehydes having no substituent in ortho-positions. The main purpose of this article is to highlight this repetitive assignment error in the literature and thus increase the likelihood of correct assignments in future papers.

Lizard tail spinal cord: a new experimental model of spinal cord injury without limb paralysis.

Spinal cord injury (SCI) is a well-known devastating lesion that sadly is very resistant to all treatment attempts. This fact has stimulated the exploration of multiple regenerative strategies that are examined at both the basic and clinical level. For laboratory research, differentin vivomodels are used, but each has many important limitations.

Synthesis of lucifensin by native chemical ligation and characteristics of its isomer having different disulfide bridge pattern.

The antimicrobial 40-amino-acid-peptide lucifensin was synthesized by native chemical ligation (NCL) using N-acylbenzimidazolinone (Nbz) as a linker group. NCL is a method in which a peptide bond between two discreet peptide chains is created. This method has been applied to the synthesis of long peptides and proteins when solid-phase synthesis is imcompatible.

Quinacrine reactivity with prion proteins and prion-derived peptides.

Quinacrine is a drug that is known to heal neuronal cell culture infected with prions, which are the causative agents of neurodegenerative diseases called transmissible spongiform encephalopathies. However, the drug fails when it is applied in vivo. In this work, we analyzed the reason for this failure.

Essential and nonessential elements in nestling rooks Corvus frugilegus from eastern Poland with a special emphasis on their high cadmium contamination.

Concentration of minerals (sodium, potassium, calcium [Ca], magnesium, iron [Fe], copper, zinc [Zn], manganese [Mn], and cobalt) as well as toxic metals (cadmium [Cd], lead [Pb]) were determined in five tissues (liver, lung, kidney, muscle, and bone) of nestling rooks (Corvus frugilegus; 1 to 13 days old) found dead in seven breeding colonies in eastern Poland. Cd concentration in all analyzed tissues was in the narrow range of 17.0-17.

Comparative syntheses of peptides and peptide thioesters derived from mouse and human prion proteins.

Prions are suspected as causative agents of several neuropathogenic diseases, even though the mode of their action is still not clear. A combination of chemical and recombinant syntheses can provide suitable probes for explanation of prions role in pathogenesis of neurodegenerative diseases. However, the prions contain several difficult sequences for synthesis by Fmoc/tBu approach.

One-electron reduction of an "extended viologen" p-phenylene-bis-4,4'-(1-aryl-2,6-diphenylpyridinium) dication.

One-electron reduction of the "extended viologen" dication 1 yields the red cation radical 2, characterized by strong near-IR absorption. It has been generated and studied by pulse radiolytic, electrochemical, redox titration, UV-visible, and electron paramagnetic resonance spectroscopic methods. All results are in agreement with a fully delocalized electronic structure for 2.