RESUMO
Circular RNAs have been extensively studied in eukaryotes, but their presence and/or biological functionality in bacteria are unclear. Here, we show that a regulatory noncoding RNA (DucS) exists in both linear and circular conformation in Bacillus altitudinis. The linear forms promote B. altitudinis tolerance to H2O2 stress, partly through increased translation of a stress-responsive gene, htrA. The 3' end sequences of the linear forms are crucial for RNA circularization, and formation of circular forms can decrease the levels of the regulatory linear cognates. Bioinformatic analysis of available RNA-seq datasets from 30 bacterial species revealed multiple circular RNA candidates, distinct from DucS, for all the examined species. Experiments testing for the presence of selected circular RNA candidates in four species successfully validated 7 out of 9 candidates from B. altitudinis and 4 out of 5 candidates from Bacillus paralicheniformis; However, none of the candidates tested for Bacillus subtilis and Escherichia coli were detected. Our work identifies a dual-conformation regulatory RNA in B. altitutidinis, and indicates that circular RNAs exist in diverse bacteria. However, circularization of specific RNAs does not seem to be conserved across species, and the circularization mechanisms and biological functionality of the circular forms remain unclear.
Assuntos
Peróxido de Hidrogênio , RNA Circular , RNA Circular/genética , Peróxido de Hidrogênio/toxicidade , RNA não Traduzido/genética , Estresse Oxidativo/genética , RNA , Escherichia coliRESUMO
Three new flavonol glycosides (1-3), hippophins K-M, were isolated from the seed residue of Hippophae rhamnoides subsp. sinensis. The chemical structures of these three new compounds were identified by 1D, 2D NMR, mass spectroscopy and high resolution electrospray ionization mass spectrometry spectroscopic data and by comparison with the literature data. This report is a continuous research work on the systematic chemical investigation of plants of the genus Hippophae in our laboratory.
Assuntos
Medicamentos de Ervas Chinesas/isolamento & purificação , Flavonoides/isolamento & purificação , Hippophae/química , Medicamentos de Ervas Chinesas/química , Flavonoides/química , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Sementes/químicaRESUMO
Three monoterpenoids and two triterpenoids were isolated from Abies nephrolepis together with 53 known terpenoids. The structures of the compounds were established by 1D and 2D NMR spectroscopy. The absolute configuration of 3-hydroxycamphane-2-carboxylic acid was established as (1S,2R,3S,4R) by Cu-Kα X-ray crystallography. All 58 isolates were tested for cytotoxic activity against four tumor cells viz. A549 (human lung adenocarcinoma), Colo205 (colon adenocarcinoma), QGY-7703 (human hepatoma) and THP-1 (human monocytic leukemia). α-Cadinol exhibited the best effects on A549, Colo205 and QGY-7703 with IC(50) values of 8.6, 8.1 and 4.6 µg/mL, respectively.
Assuntos
Abies/química , Antineoplásicos Fitogênicos/uso terapêutico , Canfanos/isolamento & purificação , Neoplasias/tratamento farmacológico , Fitoterapia , Extratos Vegetais/uso terapêutico , Terpenos/uso terapêutico , Antineoplásicos Fitogênicos/isolamento & purificação , Antineoplásicos Fitogênicos/farmacologia , Canfanos/química , Linhagem Celular Tumoral , Humanos , Concentração Inibidora 50 , Estrutura Molecular , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Terpenos/isolamento & purificação , Terpenos/farmacologiaRESUMO
The title compound, C(30)H(48)O(3), was extracted from the plant Dracocephalum rupestre Hance. The mol-ecule contains five fused cyclo-hexane rings and one five-membered lactone ring. Inter-molecular O-Hâ¯O hydrogen bonds between the hydroxyl and carbonyl groups link the mol-ecules into chains along [010]. The absolute structure has not been determined.
