Project description:Multi-drug resistant bacteria are not effectively managed with current treatments, making it a serious global problem. Therefore, there is an essential need for finding new antimicrobial agents. In this regard, silver nanoparticles (Ag-NPs) have been projected as a new generation of antimicrobial agents. Ag-NPs were biomediated by Egyptian Streptomyces roseolus for the first time, which was molecularly identified using 16S rRNA sequencing under accession no. MT071505. Biosynthesized Ag-NPs were characterized using UV-Vis spectroscopy, XRD, TEM, FTIR, and DLS. FTIR analysis confirmed the presence of different bioactive functional groups, such as N-H, C-H, C-O-C, C-NH2, and C=O acting as bioreducing/stabilizing agents for Ag-NPs. Ag-NPs exhibited antimicrobial activity against some multi-drug resistant Gram-positive and Gram-negative pathogens. MBC of Ag-NPs against Listeria monocytogenes and Klebsiella pneumonia were 0.195 and 0.048 mg/mL, respectively, with a tolerance level of 2 confirming its biocidal effect. SEM imaging of Ag-NPs-treated L. monocytogenes and K. pneumonia showed shrunk destroyed cells after 6 h of treatment. Biosynthesized Ag-NPs exhibited IC50 of < 0.3 and 8.21 mg/mL, on normal Human Skin Fibroblast, and Blood Lymphocytes, respectively. IC50 values were significantly higher than its MBC values, with no harmful cytotoxic effect, thus can be safely applied at its biocidal concentration. For biosafety purposes, the genotoxicity of biosynthesized Ag-NPs was assessed using Comet assay for the first time on Blood Lymphocytes, with zero-tail and 100% head intensity indicating non-genotoxic effect. An ecofriendly biomediated synthesis of Ag-NPs was described with easy scale-up, non-toxic by-products, so, it can be recommended as a powerful-safe antimicrobial agent.

| S-EPMC8794943 | biostudies-literature

Streptomyces roseolus strain:NBRC 12816

Project description:Streptomyces roseolus strain:NBRC 12816 Genome sequencing and assembly

| PRJNA1028839 | ENA

Effect of <i>Streptomyces roseolus</i> Cell-Free Supernatants on the Fungal Development, Transcriptome, and Aflatoxin B1 Production of <i>Aspergillus flavus</i>.

Project description:Crop contamination by aflatoxin B1 (AFB1), an Aspergillus-flavus-produced toxin, is frequently observed in tropical and subtropical regions. This phenomenon is emerging in Europe, most likely as a result of climate change. Alternative methods, such as biocontrol agents (BCAs), are currently being developed to reduce the use of chemicals in the prevention of mycotoxin contamination. Actinobacteria are known to produce many bioactive compounds, and some of them can reduce in vitro AFB1 concentration. In this context, the present study aims to analyze the effect of a cell-free supernatant (CFS) from Streptomyces roseolus culture on the development of A. flavus, as well as on its transcriptome profile using microarray assay and its impact on AFB1 concentration. Results demonstrated that in vitro, the S. roseolus CFS reduced the dry weight and conidiation of A. flavus from 77% and 43%, respectively, and was therefore associated with a reduction in AFB1 concentration reduction to levels under the limit of quantification. The transcriptomic data analysis revealed that 5198 genes were differentially expressed in response to the CFS exposure and among them 5169 were downregulated including most of the genes involved in biosynthetic gene clusters. The aflatoxins' gene cluster was the most downregulated. Other gene clusters, such as the aspergillic acid, aspirochlorine, and ustiloxin B gene clusters, were also downregulated and associated with a variation in their concentration, confirmed by LC-HRMS.

| S-EPMC10467112 | biostudies-literature

Effect of Streptomyces roseolus cell free supernatant on fungal development, transcriptome and aflatoxin B1 production of Aspergillus flavus

Project description:Frequently observed in tropical and sub-tropical regions, crops contamination by aflatoxin B1 (AFB1) produced by Aspergillus flavus, is emerging in Europe, due to climate change. Many alternative methods are currently developed to reduce the use of chemical inputs to prevent mycotoxin contamination, such as biocontrol agents (BCAs). Actinobacteria are known to produce many bioactive compounds and some of them are able to reduce in vitro AFB1 concentration. In this context, the present study aims to analyze the effect of a cell free supernatant (CFS) from Streptomyces roseolus liquid culture on A. flavus development, as well as on its transcriptome profile using microarray assay and its impact on AFB1 concentration. To study the impact of Streptomyces roseolus cell free supernatant on global transcriptome of Aspergillus flavus we have employed whole genome microarray expression profiling.

2023-09-06 | GSE232607 | GEO

Streptomyces sp. A2-16

Project description:Streptomyces. sp A2-16 Genome sequencing and assembly

| PRJNA671550 | ENA

Streptomyces roseolus strain:TRS10 | isolate:Inside cotton stem

Project description:Streptomyces roseolus strain:TRS10 | isolate:Inside cotton stem Genome sequencing

| PRJNA1189850 | ENA

Streptomyces coelicolor A3(2)

Project description:ANTIBIOTICS OVERPRODUCTION IN STREPTOMYCES COELICOLOR A3(2) MEDIATED BY PHOSPHOFRUCTOKINASE A2 DELETION

| PRJNA99439 | ENA