Nicholas Radvanyi
Ontology highlight
ABSTRACT:
SUBMITTER:
PROVIDER: S-EPMC1125678 | biostudies-literature | 2003 Apr
REPOSITORIES: biostudies-literature
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Project description: Not available
| S-EPMC1633810 | biostudies-literature
Project description:Transcriptome responses to dietary aflatoxin B1 exposure in domestic turkey
| PRJNA251549 | ENA
Project description:The scope and limitations of the Nicholas-type cyclization for the synthesis of 10-membered benzothiophene-fused heterocyclic enediynes with different functionalities were investigated. Although the Nicholas cyclization through oxygen could be carried out in the presence of an ester group, the final oxaenediyne was unstable under storage. Among the N-type Nicholas reactions, cyclization via an arenesulfonamide functional group followed by mild Co-deprotection was found to be the most promising, yielding 10-membered azaendiynes in high overall yields. By contrast, the Nicholas cyclization through the acylated nitrogen atom did not give the desired 10-membered cycle. It resulted in the formation of a pyrroline ring, whereas cyclization via an alkylated amino group resulted in a poor yield of the target 10-membered enediyne. The acylated 4-aminobenzenesulfonamide nucleophilic group was found to be the most convenient for the synthesis of functionalized 10-membered enediynes bearing a clickable function, such as a terminal triple bond. All the synthesized cyclic enediynes exhibited moderate activity against lung carcinoma NCI-H460 cells and had a minimal effect on lung epithelial-like WI-26 VA4 cells and are therefore promising compounds in the search for novel antitumor agents that can be converted into conjugates with tumor-targeting ligands.
| S-EPMC9502870 | biostudies-literature
Project description:Cyclic products can be obtained through the intramolecular version of the Nicholas reaction, which requires having the nucleophile connected to the alkyne unit. Here, we report the synthesis of 1-oxa-3-cyclooctynes starting from commercially available (1R,3S)-camphoric acid. The strategy is based on the initial preparation of propargylic alcohols, complexation of the triple bond with Co2(CO)8, and treatment with BF3·Et2O to induce an intramolecular Nicholas reaction with the free hydroxyl group as nucleophile. Finally, oxidative deprotection of the alkyne afforded the cyclooctynes in good yields. Notably, large-sized R substituents at the chiral center connected to the O atom were oriented in such a way that steric interactions were minimized in the cyclization, allowing the formation of cyclooctynes exclusively with (R) configuration, in good agreement with theoretical predictions. Moreover, preliminary studies demonstrated that these cyclooctynes were reactive in the presence of azides yielding substituted triazoles.
| S-EPMC7999112 | biostudies-literature
Project description:We report here the complete genome sequences of four subcluster L3 mycobacteriophages newly isolated from soil samples, using Mycobacterium smegmatis mc2155 as the host. Comparative genomic analyses with four previously described subcluster L3 phages reveal strong nucleotide similarity and gene conservation, with several large insertions/deletions near their right genome ends.
| S-EPMC5679797 | biostudies-literature
Project description:Accurate unambiguous identification of ancient or historical specimens can potentially be achieved by DNA analysis. The controversy surrounding the fate of the last Russian Emperor, Nicholas II, and his family has persisted, in part, because the bodies of 2 children, Prince Alexei and 1 of his sisters, have not been found. A grave discovered in 1991 contained remains putatively identified as those of the Russian Royal family. However, not all family members were represented. Here, we report the results of genomic analyses of new specimens, the human remains of 2 burned skeletons exhumed from a grave discovered in July 2007, and the results of a comprehensive genomic analysis of remains from the 1991 discovery. Additionally, approximately 117 years old archival blood specimens from Nicholas II were obtained and genotyped, which provided critical material for the specific determination of individual identities and kinship identifications. Results of genotypic analyses of damaged historical specimens were evaluated alongside samples from descendants of both paternal and maternal lineages of the European Royal families, and the results conclusively demonstrate that the recently found remains belong to children of Nicholas II: Prince Alexei and his sister. The results of our studies provide unequivocal evidence that the remains of Nicholas II and his entire family, including all 5 children, have been identified. We demonstrate that convergent analysis of complete mitochondrial genome sequences combined with nuclear DNA profiles is an efficient and conclusive method for individual and kinship identification of specimens obtained from old historic relics.
| S-EPMC2664067 | biostudies-literature