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- Coumarin-based combined computational study to design novel drugs against Candida albicans
- Akhilesh Kumar Maurya , Nidhi Mishra
- J. Microbiol. 2022;60(12):1201-1207. Published online November 10, 2022
- DOI: https://doi.org/10.1007/s12275-022-2279-5
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Abstract
- Candida species cause the most prevalent fungal illness, candidiasis. Candida albicans is known to cause bloodstream infections. This species is a commensal bacterium, but it can cause hospital–acquired diseases, particularly in COVID-19 patients with impaired immune systems. Candida infections have increased in patients with acute respiratory distress syndrome. Coumarins are both naturally occurring and synthetically produced. In this study, the biological activity of 40 coumarin derivatives was used to create a three-dimensional quantitative structure activity relationship (3D-QSAR) model. The training and test minimum inhibitory concentration values of C. albicans active compounds were split, and a regression model based on statistical data was established. This model served as a foundation for the creation of coumarin derivative QSARs. This is a unique way to create new therapeutic compounds for various ailments. We constructed novel structural coumarin derivatives using the derived QSAR model, and the models were confirmed using molecular docking and molecular dynamics simulation.
Research Support, Non-U.S. Gov'ts
- Role of the extracytoplasmic function sigma factor CarQ in oxidative response of Bradyrhizobium japonicum
- Anchana Thaweethawakorn , Dylan Parks , Jae-Seong So , Woo-Suk Chang
- J. Microbiol. 2015;53(8):526-534. Published online July 31, 2015
- DOI: https://doi.org/10.1007/s12275-015-5308-9
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- 3 Citations
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Abstract
- As a nitrogen-fixing bacterium, Bradyrhizobium japonicum can establish a symbiotic relationship with the soybean plant (Glycine max). To be a successful symbiont, B. japonicum must deal with plant defense responses, such as an oxidative burst. Our previous functional genomics study showed that carQ (bll1028) encoding extracytoplasmic function (ECF) sigma factor was highly expressed (107.8-fold induction) under oxidative stress. Little is known about the underlying mechanisms of how CarQ responds to oxidative stress. In this study, a carQ knock-out mutant was constructed using site-specific mutagenesis to identify the role of carQ in the oxidative response of B. japonicum. The carQ mutant showed a longer generation time than the wild type and exhibited significantly decreased survival at 10 mM H2O2 for 10 min of exposure. Surprisingly, there was no significant difference in expression of oxidative stress-responsive genes such as katG and sod between the wild type and carQ mutant. The mutant also showed a significant increase in susceptibility to H2O2 compared to the wild type in the zone inhibition assay. Nodulation phenotypes of the carQ mutant were distinguishable compared to those of the wild type, including lower numbers of nodules, decreased nodule dry weight, decreased plant dry weight, and a lower nitrogen fixation capability. Moreover, desiccation of mutant cells also resulted in significantly lower percent of survival in both early (after 4 h) and late (after 24 h) desiccation periods. Taken together, this information will provide an insight into the role of the ECF sigma factor in B. japonicum to deal with a plant-derived oxidative burst.
- Factors Influencing Preferential Utilization of RNA Polymerase Containing Sigma-38 in Stationary-Phase Gene Expression in Escherichia coli
- Eun Young Kim , Min-Sang Shin , Joon Haeng Rhee , Hyon E. Choy
- J. Microbiol. 2004;42(2):103-110.
- DOI: https://doi.org/2037 [pii]
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Abstract
- In order to understand the molecular basis of selective expression of stationary-phase genes by RNA polymerase containing [sigma]^38 (E[sigma]^38) in Escherichia coli, we examined transcription from the stationaryphase promoters, katEP, bolAP, hdeABP, csgBAP, and mcbP, in vivo and in vitro. Although these promoters are preferentially recognized in vivo by E[sigma]^38, they are transcribed in vitro by both E[sigma]^38 and E[sigma]^70 containing the major exponential [sigma], [sigma]^70. In the presence of high concentrations of glutamate salts, however, only E[sigma]^38 was able to efficiently transcribe from these promoters, which supports the concept that the promoter selectivity of [sigma]^38 -containing RNA polymerase is observed only under specific reaction conditions. The examination of 6S RNA, which is encoded by the ssr1 gene in vivo, showed that it reduced E[sigma]^70 activity during the stationary phase, but this reduction of activity did not result in the elevation of E[sigma]^38 activity. Thus, the preferential expression of stationary-phase genes by E[sigma]^38 is unlikely the consequence of selective inhibition of E[sigma]^70 by 6S RNA.
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