The new shed on silver’s antimicrobial activity. As the commonly prescribed anti-bacterial superbug bacteria have become a global threat to public health in recent years, noble metals, such as silver, are gaining widespread attention due to their antimicrobial activities in various forms.
The new shed
While how silver kills bacteria remains a mystery. A team of researchers at the University of Arkansas has studied the antimicrobial effect of nanoscale silver ions on protein dynamics in living bacteria.
Sedoon et al studied the antimicrobial effect of nanoscale silver ions on the tectonic dynamics of histone-like nucleoid structuring proteins in live Escherichia coli bacteria using single-track photographic localization microscopy.
University of Arkansas
Traditionally, the antimicrobial effects of silver have been measured through biomass, which compares the effect of a substance on a test organism with a standard untreated preparation,” said lead author Dr. Said Yong Wang, scientist in the physics department of University of Arkansas.
“While these methods are effective, they typically produce only snapshots on time.” Instead, Drs. Wang and his colleagues used an advanced imaging technique called single-particle tracking, photactined location microscopy to visualize and track a particular protein found in the Escherichia coli bacteria over time.
They were surprised to learn that silver ions actually affect protein dynamics, which they believe would be the opposite. Silver ions are known to suppress and kill bacteria; therefore, we expected that everything in bacteria would slow down when treated with silver.
But unsurprisingly, we found that the dynamics of this protein accelerated, he said. Dr. Wang said. The study authors found that silver ions were producing different DNA strands in bacteria, and the bonds between proteins and DNA were weakened.
So you can understand the rapid movement of the protein due to silver, said Dr.Wang. When a protein binds to DNA, it moves slowly with DNA, a large molecule in bacteria. By contrast, when treated with silver, the protein collapses from DNA, moving rapidly on its own and therefore.
The observation of DNA segregation due to silver ions came from earlier work that Dr. Wang and his co-authors did with DNA from Tula. Their approach was to stress the DNA strand by stressing them, making them more susceptible to interactions with other chemicals, including silver ions.
“The study validated the idea of investigating the dynamics of individual proteins in bacteria,” said Dr. Wang said. “What we finally want to do is use the new knowledge generated from this project to create a better antibiotic based on silver nanoparticles.”
Effect of surface charge of silver nanoparticles on antimicrobial activity against gram positive and gram negative bacteria: a preliminary study. The bactericidal efficacy of various positively and negatively charged silver nanoparticles has been widely evaluated in the literature.
But there are no reports on the efficacy of neutrally charged silver nanoparticles. The objective of this study is to evaluate the role of electrical charge on the surface of silver nanoparticles in antibacterial activity against a panel of microorganisms.
Three different silver nanoparticles were synthesized in different ways, producing three different electrical surface charges (positive, neutral, and negative). The antibacterial activity of these nanoparticles was tested against Gram positive bacteria (i.e. Staphylococcus aureus, Streptococcus mutans and Streptococcus pyogen) and Gram negative (i.e. Escherichia coli and Proteus vulgaris).
Well diffusion and microdilution tests were used to evaluate the bactericidal activity of the nanoparticles. According to the results obtained, the positively charged silver nanoparticles showed the highest bactericidal activity against all the tested microorganisms. The negatively charged silver nanoparticles had minimal antibacterial activity on minimal and neutral nanoparticles.
The most resistant bacteria were the vulgar protein. We found that the surface charge of silver nanoparticles was an important factor affecting bactericidal activity on these surfaces. Although positively charged nanoparticles showed the highest level of effectiveness against tested organisms, neutrally charged particles were also potent against most bacterial Species.
Antimicrobial activity against pathogenic microorganisms by extracts of Jordan herbal plants. The analyzed medicinal plants showed antimicrobial activity against the analyzed microorganisms in varying amounts of extract (5, 10, 15, 20, 40, 60, 80 and 100 ppm).
The minimum inhibitory concentrations (MIC) and the diameter of the zone of inhibition (DIZ) were determined by in vitro bioassays using the perforated plate diffusion method against two bacterial species, Staphylococcus aureus and Pseudomonas aerugorosa, and a fungus, Candida albicans.
Most of the plant extracts tested, except Arum hygrophilum and the nerve micrometer, showed antimicrobial activity against some tested microorganisms. Antimicrobial activity was highest in Crumina crupinastrum extracts (5, 10, 15, 20, 40 and 60 ppm), which gave the largest zone of inhibition (DIZ 24 mm) at 60 ppm, followed by Akilia bibbersteniii extract at 60 ppm.
It was the effect. (DIZ 18 mm). This study highlighted the antimicrobial potential of Jordanian medicinal plant extracts, which can be used as natural antimicrobial agents in pharmaceutical and food preservation systems. The results were published in the Journal of Applied and Environmental Microbiology. Research highlights how silver ions kill bacteria. The antimicrobial properties of silver have been known for centuries.
While how silver kills bacteria remains a mystery, Arkansas researchers have taken a step toward a better understanding of the process by looking at the protein dynamics in living bacteria at the molecular level. Traditionally, the antimicrobial effects of silver have been measured through biases, which compare the effect of a substance on a test organism with a standard untreated preparation.
While these methods are effective, they generally only produce snapshots on time, Yong Wang, an assistant professor of physics and study author, has published in the journal Applied and Environmental Microbiology. Instead, Wang and his colleagues used an advanced imaging technique, called “single-particle scanning photactinized localization microscopy,” to visualize and track a particular protein found in the E. coli bacteria over time.
The researchers were surprised to learn that silver ions actually affect protein dynamics, which they believe would be the opposite. Silver ions are known to suppress and kill bacteria, said Wang. We were expecting how everything in bacteria would slow down when treated with silver. But surprisingly, we found that this protein accelerated.
Large molecule in bacteria
The researchers discovered that silver ions were causing DNA pairs to separate in bacteria and weakened the bonds between proteins and DNA. Then you can understand the rapid mobility of the protein due to silver, said Wang. When a protein binds to DNA, it slowly moves along DNA, which is a large molecule in bacteria.
On the contrary, when it comes to silver, proteins fall out of DNA, grow faster than me and so on. The observation of DNA dissociation due to silver ions came from earlier work that Wang and his colleagues had done with Tula’s DNA.
His now patent-pending approach was to pressurize DNA strands by bending them, making them more susceptible to interaction with other chemicals, including silver ions. The study, funded by the National Science Foundation, validated the idea of investigating the dynamics of individual proteins in living bacteria.
An approach has been proposed that could help researchers understand bacteria’s real-time reactions to silver nanoparticles to fight so-called “superbugs” that are resistant to commonly prescribed antibiotics. What we finally want to do is use the new knowledge generated by this project to create a better antibiotic based on silver nanoparticles, said Wang.