Aim The objective of this study was to investigate the biofilm inhibitory activity of Streptomyces‐derived actinomycin D against biofilm formation by Staphylococcus epidermidis. Methods and Results The microtitre plate method and microscopy were used to detect the biofilm formation of S. epidermidis. And an attempt was made to detect the effect of actinomycin D on important biofilm components, exopolysaccharides (EPS) in S. epidermidis using precolumn derivation HPLC. Also cell surface hydrophobicities of S. epidermidis were assessed to explore action mechanisms. The qPCR was performed to demonstrate the genetic mechanisms of biofilm formation by S. epidermidis. Unlike other antibiotics, actinomycin D (1·5 μg ml−1) from Streptomyces luteus significantly inhibited biofilm formation by S. epidermidis. Additionally, it effectively inhibited S. epidermidis cells from adhering to glass slides. Actinomycin D downregulated ica locus and then the reduced polysaccharide intercellular adhesin production caused S. epidermidis cells to become less hydrophobic, thus supporting its anti‐biofilm effect. Conclusion Streptomyces‐derived actinomycin D is active in inhibiting the biofilm formation of S. epidermidis. Significance and Impact of the Study Actinomycin D can be used as a promising antibiofilm agent in inhibiting S. epidermidis biofilm formation. The study is also the first insight into how actinomycin D inhibited the biofilm formation of S. epidermidis. Actinomycin D could potentially be used to reduce the risk of biofilm‐associated infections. Our study also suggests that the metabolites from Actinomycete strains keep further attention as potential antibiofilm agents against biofilm formation of S. epidermidis, even biofilm infections of the other bacteria.
Aims: To isolate and characterize the novel Bacillus thuringiensis strains from bryophytes collected from Wuyi Mountain, Fujian Province of China, and identify new B. thuringiensis strains and toxins active against mosquitoes. Methods and Results: Twelve novel B. thuringiensis strains were isolated from 76 bryophyte samples. According to the results of this preliminary screening, LLB6 was the most toxic to Aedes albopictus. Then phase-contrast as well as scanning electron microscopy, bioassays, cloning, sequencing and expression were performed to characterize the novel isolate LLB6 and its new gene cry2Ac5. Conclusions: Bacillus thuringiensis occurred naturally on bryophytes. LLB6 isolated from Physcomitrium japonicum was toxic to A. albopictus. A new cry2Ac5 gene of LLB6 was detected, cloned and expressed successfully. Bioassays on A. albopictus showed that the expressed Cry2Ac5 was also toxic to the third instar larvae. Significance and Impact of the Study: This is the first report of B. thuringiensis strains isolated from bryophytes. It represents a specific source of new B. thuringiensis strains and is of great importance for the knowledge of the ecology of B. thuringiensis. Novel LLB6 harboring the new gene cry2Ac5 and its expressed Cry2Ac5 protein revealed activity against A. albopictus and became a new member of B. thuringiensis toxins. 301Japanese encephalitis all over the world. About 20 million people are infected by dengue virus transmitted by Aedes mosquitoes with about 24 000 deaths every year. Therefore, mosquito management is an essential component for the control of mosquito-borne diseases. It has been known that the cyt and cry genes (cyt1, cyt2, cry2, cry4, cry10 and cry11) of B. thuringiensis encode the proteins active against mosquitoes. However, insect resistance to B. thuringiensis, especially to Cry proteins, has been found in recent years. Moreover, the similar or even higher level of insect resistance to commercial B. thuringiensis products has been reported in many countries. As a result of the severe impact of mosquito-borne diseases on public health, identification of new B. thuringiensis strains and toxins active against mosquitoes has increasingly come to attention (Schnepf et al. 1998).Wuyi Mountain is one of the world's natural and cultural heritages in China. It has a typical moderate subtropical climate with abundant rainfall, and warm and humid weather. The bryophyte samples collected from Wuyi Mountain were used to isolate B. thuringiensis. The purpose was to gain more information on the distribution of B. thuringiensis populations and to screen the strains active against A. albopictus. LLB6 was obtained and found to contain the cry2Ac gene, encoding protein toxic to Dipteran insects. To learn more about the characteristics of the cry2Ac gene of LLB6 and its encoding protein, we cloned and sequenced this gene, and successfully expressed the protein in Escherichia coli BL21. The Cry2Ac of LLB6 had been named as Cry2Ac5 by the B. thuringiensis delta-endotoxin nomenclatu...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.