Biosynthesis, characterization, and in vitro assessment on cytotoxicity of actinomycete-synthesized silver nanoparticles on Allium cepa root tip cells

Abstract

Background The industrial production of silver nanoparticles (AgNPs) and its commercial applications are being considerably increased in recent times, resulting in the release of AgNPs in the environment and enhanced probability of contaminations and their adverse effects on living systems. Based on this, the present study was conducted to evaluate the in vitro cytotoxicity of actinomycete-synthesized AgNPs on Allium cepa (A. cepa) root tip cells. A green synthesis method was employed for biosynthesis of AgNPs from Streptomyces sp. NS-33. However, morphological, physiological, biochemical, and molecular analysis were carried out to characterize the strain NS-33. Later, the synthesized AgNPs were characterized and antibacterial activity was also carried out against pathogenic bacteria. Finally, cytotoxic activity was evaluated on A. cepa root tip cells. Results Results showed the synthesis of spherical and polydispersed AgNPs with a characteristic UV-visible (UV-Vis.) spectral peak at 397 nm and average size was 32.40 nm. Energy dispersive spectroscopy (EDS) depicted the presence of silver, whereas Fourier transform infrared (FTIR) studies indicated the presence of various functional groups. The phylogenetic relatedness of Streptomyces sp. NS-33 was found with Streptomyces luteosporeus through gene sequencing. A good antibacterial potential of AgNPs was observed against two pathogenic bacteria. Concerning cytotoxicity, a gradually decreased mitotic index (MI) and increased chromosomal aberrations were observed along with the successive increase of AgNPs concentration. Conclusions Therefore, the release of AgNPs into the environment must be prevented, so that it cannot harm plants and other beneficial microorganisms.

Bioprospection and secondary metabolites profiling of marine Streptomyces levis strain KS46

“…strain KS46 showed spiral spore chain having smooth spores. This result is in compliance with the report of Nayaka et al (2020) , where the Streptomyces sp. NS-33 produced flat and irregular shaped colonies.…”

“…The actinomycetes were differentiated from diverse microbial colonies by their appearance, such as leathery, tough, powdery, dry, fuzzy and pigmented colonies. The isolated colonies were preserved in SA medium at 4 °C for future studies ( Njenga et al, 2017 , Nayaka et al, 2020 ).…”

“…strain KS46 was carried out by 16S rRNA gene sequencing. The genomic DNA of the strain was extracted with the help of HipurA Streptomyces DNA purification kit (MB527) according to manufacturer’s instructions ( Nayaka et al, 2020 ).…”

Plumeria alba-Mediated Green Synthesis of Silver Nanoparticles Exhibits Antimicrobial Effect and Anti-Oncogenic Activity against Glioblastoma U118 MG Cancer Cell Line

“…NS-36 with a characteristic UV-visible (UV-Vis.) spectral peak at 397 nm and average size of 32.40 nm, showed a good zone of inhibition against E. faecalis, a moderate zone against E. coli and S. aureus, and the least zone of inhibition against S. pneumonia [59].…”

Green synthesis of Silver nanoparticles using Streptomyces hirsutus strain SNPGA-8 and their characterization, antimicrobial activity, and anticancer activity against human lung carcinoma cell line A549

“…Metal nanoparticles possess unique physical traits like size, shape, and a larger surface area to volume ratio. The synthesis of nanoparticles is done from various metals like gold ( Camas et al, 2019 ), silver ( Nayaka et al, 2020a ), copper ( Hassan et al, 2019 ), magnesium ( Imani & Safaei, 2019 ), zinc ( Kalpana et al, 2018 , Menazea and Awwad, 2020 ), and titanium ( Eisa et al, 2020 ). However, AgNPs are gaining great interest due to their diversified utilization in various areas such as biosensing ( Salem & Fouda, 2021 ), drug delivery ( Lee & Jun 2019 ), nano-device fabrication, medicine ( Ahmed and Mustafa, 2020 , Zahin et al, 2020 ) gene delivery systems ( Sung & Kim, 2019 ), and artificial implants ( Ziąbka et al, 2018 ).…”