One-Time Addition of Nano-TiO2 Triggers Short-Term Responses in Benthic Bacterial Communities in Artificial Streams.

Nano-TiO2 is an engineered nanomaterial whose production and use are increasing rapidly. Hence, aquatic habitats are at risk for nano-TiO2 contamination due to potential inputs from urban and suburban runoff and domestic wastewater. Nano-TiO2 has been shown to be toxic to a wide range of aquatic organisms, but little is known about the effects of nano-TiO2 on benthic microbial communities.

Combined Toxicity of Nano-ZnO and Nano-TiO2: From Single- to Multinanomaterial Systems.

Previous studies on the toxicity of engineered nanomaterials (ENMs) have been primarily based on testing individual ENMs, so little is known about the interactions and combined toxicity of multiple ENMs. In this study the toxicity of chemically stable nano-TiO2 and soluble nano-ZnO was investigated individually and in combination, by monitoring bacterial cell membrane integrity and ATP levels in a natural aqueous medium (Lake Michigan water). Both nano-TiO2 and nano-ZnO damage bacterial cell membranes under simulated solar irradiation (SSI), but their phototoxicity is not additive.

Comparing Acute Effects of a Nano-TiO2 Pigment on Cosmopolitan Freshwater Phototrophic Microbes Using High-Throughput Screening.

Production of titanium-dioxide nanomaterials (nano-TiO2) is increasing, leading to potential risks associated with unintended release of these materials into aquatic ecosystems. We investigated the acute effects of nano-TiO2 on metabolic activity and viability of algae and cyanobacteria using high-throughput screening. The responses of three diatoms (Surirella angusta, Cocconeis placentula, Achnanthidium lanceolatum), one green alga (Scenedesmus quadricauda), and three cyanobacteria (Microcystis aeruginosa, Gloeocapsa sp.

Acute effects of TiO2 nanomaterials on the viability and taxonomic composition of aquatic bacterial communities assessed via high-throughput screening and next generation sequencing.

The nanotechnology industry is growing rapidly, leading to concerns about the potential ecological consequences of the release of engineered nanomaterials (ENMs) to the environment. One challenge of assessing the ecological risks of ENMs is the incredible diversity of ENMs currently available and the rapid pace at which new ENMs are being developed. High-throughput screening (HTS) is a popular approach to assessing ENM cytotoxicity that offers the opportunity to rapidly test in parallel a wide range of ENMs at multiple concentrations.

Common freshwater bacteria vary in their responses to short-term exposure to nano-TiO2.

Nanostructured titania (nano-TiO2) is an engineered nanomaterial that can be cytotoxic primarily as a result of its ability to generate reactive oxygen species when illuminated. Production of nano-TiO2 has increased rapidly over the last decade, leading to concerns about its release into aquatic environments. To address the possible ecological impacts of nano-TiO2, the authors used high-throughput screening to assess the responses of 4 bacteria representative of genera common in freshwater to short-term exposure (1-2 h) in 2 natural aqueous media (stream water and lake water) to 2 widely used TiO2 products, pigment white 6 (PW6) and P25.

Effects of material morphology on the phototoxicity of nano-TiO2 to bacteria.

Nanostructured titania (nano-TiO2) is produced in diverse shapes, but it remains largely unknown how tuning the morphology of nano-TiO2 may alter its toxicity. Herein, we show that material morphology plays a critical role in regulating the phototoxicity of nano-TiO2 to bacteria. Low-dimensional nano-TiO2, including nanotubes, nanorods, and nanosheets, were synthesized hydrothermally, and their effects on the bacterial viability of Escherichia coli and Aeromonas hydrophila were compared to spherical nanostructures (anatase nanospheres and P25).

Cytotoxicity of commercial nano-TiO2 to Escherichia coli assessed by high-throughput screening: effects of environmental factors.

The extensive use of nano-TiO2 in industry has led to growing concerns about its potential environmental impacts. However, negligible toxicity is commonly reported under insufficient illumination and artificial solution conditions in the literature, which rarely includes discussion of the regulating role of environmental factors. Herein, we report the results of a high-throughput screening assay to evaluate the acute cytotoxicity of six commercial nano-TiO2 materials to Escherichia coli (E.

Taxonomic and ecological studies of actinomycetes from Vietnam: isolation and genus-level diversity.

Actinomycetes were isolated from 109 soil and 93 leaf-litter samples collected at five sites in Vietnam between 2005 and 2008 using the rehydration-centrifugation (RC) method, sodium dodecyl sulfate-yeast extract dilution method, dry-heating method and oil-separation method in conjunction with humic acid-vitamin agar as an isolation medium. A total of 1882 strains were identified as Vietnamese (VN)-actinomycetes including 1080 (57%) streptomycetes (the genus Streptomyces isolates) and 802 (43%) non-streptomycetes. The 16S ribosomal RNA gene sequences of the VN-actinomycetes were analyzed using BLAST searches.

Piggery manure used for soil fertilization is a reservoir for transferable antibiotic resistance plasmids.

In this study, the prevalence and types of transferable antibiotic resistance plasmids in piggery manure were investigated. Samples from manure storage tanks of 15 farms in Germany were analysed, representing diverse sizes of herds, meat or piglet production. Antibiotic resistance plasmids from manure bacteria were captured in gfp-tagged rifampicin-resistant Escherichia coli and characterized.

Short-term effects of amoxicillin on bacterial communities in manured soil.

Antibiotic-resistant bacteria, nutrients and antibiotics that enter the soil by means of manure may enhance the proportion of bacteria displaying antibiotic resistance among soil bacteria and may affect bacterial community structure and function. To investigate the effect of manure and amoxicillin added to manure on soil bacterial communities, microcosm experiments were performed with two soil types and the following treatments: (1) nontreated, (2) manure-treated, (3) treated with manure supplemented with 10 mg amoxicillin kg(-1) soil and (4) treated with manure supplemented with 100 mg amoxicillin kg(-1) soil, with four replicates per treatment. Manure significantly increased the total CFU count and the amoxicillin-resistant CFU count of both soil types.