Discovery of CRR1-targeted copper deficiency response in Chlamydomonas reinhardtii exposed to silver nanoparticles

Changes of Gene Expression Patterns from Aquatic Organisms Exposed to Metal Nanoparticles

Metal nanoparticles are used in various branches of industry due to their physicochemical properties. However, with intensive use, most of the waste and by-products from industries and household items, and from weathering of products containing nanoparticles, end up in the waters. These pollutants pose a risk to aquatic organisms, one of which is a change in the expression of various genes. Most of the data that focus on metal nanoparticles and their effects on aquatic organisms are about copper and silver nanoparticles, which is due to their popularity in general industry, but information about other nanoparticulate metals can also be found. This review aims to evaluate gene expression patterns in aquatic organisms by metal nanoparticles, specifying details about the transcription changes of singular genes and, if possible, comparing the changes in the expression of the same genes in different organisms. To achieve this goal, available publications tackling this problem are studied and summarized. Nanometals were found to have a modulatory effect on gene expression in different aquatic organisms. Data show both up-regulation and down-regulation of genes. Nano silver, nano copper, and nano zinc show a regulatory effect on genes involved in inflammation and apoptosis, cell cycle regulation and ROS defense as well as in general stress response and have a negative effect on the expression of genes involved in development. Nano gold, nano titanium, nano zinc, and nano iron tend to elevate the transcripts of genes involved in response to ROS, but also pro-apoptotic genes and down-regulate DNA repair-involved genes and anti-apoptotic-involved genes. Nano selenium showed a rare effect that is protective against harmful effects of other nanoparticles, but also induced up-regulation of stress response genes. This review focuses only on the effects of metal nanoparticles on the expression of various genes of aquatic organisms from different taxonomic groups.

Novel photodynamic coating reduces the bioburden on near-patient surfaces thereby reducing the risk for onward pathogen transmission: a field study in two hospitals

BACKGROUND

Near-patient surfaces are recognized as a source for hospital-acquired infections. Such surfaces act as reservoirs for microbial contamination by which pathogens can be transmitted from colonized or infected patients to susceptible patients. Routine disinfection of surfaces only results in a temporal elimination of pathogens, and recontamination inevitably occurs shortly between disinfections.

AIM

A novel antimicrobial coating based on photodynamics was tested under laboratory conditions and subsequently in a field study in two hospitals under real-life conditions.

METHODS

Identical surfaces received a photodynamic or control coating. Bacterial counts [colony-forming units (cfu)/cm²) were assessed regularly for up to 6 months.

FINDINGS

The laboratory study revealed a mean reduction of several human pathogens of up to 4.0 ± 0.3 log₁₀. The field study in near-patient environments demonstrated mean bacterial values of 6.1 ± 24.7 cfu/cm² on all control coatings. Photodynamic coatings showed a significantly lower mean value of 1.9 ± 2.8 cfu/cm² (P<0.001). When considering benchmarks of 2.5 cfu/cm² or 5 cfu/cm², the relative risk for high bacterial counts on surfaces was reduced by 48% (odds ratio 0.38, P<0.001) or 67% (odds ratio 0.27, P<0.001), respectively.

CONCLUSION

Photodynamic coatings provide a significant and lasting reduction of bacterial counts on near-patient surfaces, particularly for high bacterial loads, in addition to routine hygiene. The promising results of this proof-of-concept study highlight the need for further studies to determine how this novel technology is correlated with the frequency of hospital-acquired infections.