Urban wastewater treatment plants as hotspots for antibiotic resistant bacteria and genes spread into the environment: a review.

Principles of microbial PAH-degradation in soil.

This review deals with the prospective, experimental documentation of horizontal gene transfer (HGT) and its role in real-time, local adaptation. We have focused on plasmids and their function as an accessory and/or adaptive gene pool. Studies of the extent of HGT in natural environments have identified certain hot spots, and many of these involve biofilms. Biofilms are uniquely suited for HGT, as they sustain high bacterial density and metabolic activity, even in the harshest environments. Single-cell detection of donor, recipient and transconjugant bacteria in various natural environments, combined with individual-based mathematical models, has provided a new platform for HGT studies.

Studying plasmid horizontal transfer in situ : a critical review

The current fossil fuel-based generation of energy has led to large-scale industrial development. However, the reliance on fossil fuels leads to the significant depletion of natural resources of buried combustible geologic deposits and to negative effects on the global climate with emissions of greenhouse gases. Accordingly, enormous efforts are directed to transition from fossil fuels to nonpolluting and renewable energy sources. One potential alternative is biohydrogen (H2), a clean energy carrier with high-energy yields; upon the combustion of H2, H2O is the only major by-product. In recent decades, the attractive and renewable characteristics of H2 led us to develop a variety of biological routes for the production of H2. Based on the mode of H2 generation, the biological routes for H2 production are categorized into four groups: photobiological fermentation, anaerobic fermentation, enzymatic and microbial electrolysis, and a combination of these processes. Thus, this review primarily focuses on the evaluation of the biological routes for the production of H2. In particular, we assess the efficiency and feasibility of these bioprocesses with respect to the factors that affect operations, and we delineate the limitations. Additionally, alternative options such as bioaugmentation, multiple process integration, and microbial electrolysis to improve process efficiency are discussed to address industrial-level applications.

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Biohydrogen Production: Strategies to Improve Process Efficiency through Microbial Routes

Recently, there has been tremendous interest in developing techniques such as MRI, micro-CT, micro-PET, and SPECT to image function and processes in small animals. These technologies offer deep tissue penetration and high spatial resolution, but compared with noninvasive small animal optical imaging, these techniques are very costly and time consuming to implement. Optical imaging is cost-effective, rapid, easy to use, and can be readily applied to studying disease processes and biology in vivo. In vivo optical imaging is the result of a coalescence of technologies from chemistry, physics, and biology. The development of highly sensitive light detection systems has allowed biologists to use imaging in studying physiological processes. Over the last few decades, biochemists have also worked to isolate and further develop optical reporters such as GFP, luciferase, and cyanine dyes. This article reviews the common types of fluorescent and bioluminescent optical imaging, the typical system platforms and configurations, and the applications in the investigation of cancer biology.

https://journals.sagepub.com/doi/pdf/10.1162/15353500200303142

Current advances in molecular imaging: noninvasive in vivo bioluminescent and fluorescent optical imaging in cancer research.

Bioaugmentation of microbial communities in laboratory and pilot scale sequencing batch biofilm reactors using the TOL plasmid.

We describe here a dual-labeling technique involving the green fluorescent protein (GFP) and the red fluorescent protein (DsRed) for in situ monitoring of horizontal gene transfer via conjugation. A GFPmut3b-tagged derivative of narrow-host-range TOL plasmid (pWWO) was delivered to Pseudomonas putida KT2442, which was chromosomally labeled with dsRed by transposon insertion via biparental mating. Green and red fluorescent proteins were coexpressed in donor P. putida cells. Cells expressing both fluorescent proteins were smaller in size than cells expressing GFP alone. Donors and transconjugants in mixed culture or sludge samples were discriminated on the basis of their fluorescence by using confocal laser scanning microscopy. Conjugal plasmid transfer frequencies on agar surfaces and in sludge microcosms were determined microscopically without cultivation. This method worked well for in situ monitoring of horizontal gene transfer in addition to tracking the fate of microorganisms released into complex environments. To the best of our knowledge, this is the first study that discusses the coexpression of GFP and DsRed for conjugal gene transfer studies.

Dual Labeling of Pseudomonas putida with Fluorescent Proteins for In Situ Monitoring of Conjugal Transfer of the TOL Plasmid

Polyaromatic hydrocarbons (PAHs) are ubiquitous pollutants found in high concentrations at industrial sites associated with petroleum, coal tar, gas production and wood preservation industries. Due to their carcinogenic and mutagenic properties, PAHs are considered as environmental priority pollutants. They are stable and recalcitrant in soils as they are less easy to degrade than many other organic compounds. Though feasible, bioremediation of PAH-contaminated soils is seriously hampered by the low bioavailability of these compounds, making their removal a long and difficult process. Some PAH-degrading microorganisms seem however to be adapted to face the unfavourable physico chemical- properties of PAHs. Recent studies have shown that these peculiar organisms often belong to a discrete number of bacterial or fungal genera. In this review, both physico-chemical and metabolic aspects associated with the bacterial removal of PAHs from contaminated soils are discussed, as well as the perspectives for improving the associated biological technologies.

Pierre Wattiau

Papers

Bioaugmentation of microbial communities in laboratory and pilot scale sequencing batch biofilm reactors using the TOL plasmid.

Dual Labeling of Pseudomonas putida with Fluorescent Proteins for In Situ Monitoring of Conjugal Transfer of the TOL Plasmid

Microbial Aspects in Bioremediation of Soils Polluted by Polyaromatic Hydrocarbons