live-cell-analysis-shear-stress-on-pseudomonas-aeruginosa-using-an

Live Cell Analysis of Shear Stress on <em>Pseudomonas aeruginosa</em> Using an Automated Higher-Throughput Microfluidic System

A higher-throughput microfluidic in vitro bioreactor coupled with fluorescence microscopy has been used to study bacterial biofilm growth and morphology, ...

Doane University

Plant root exudates are important mediators in the interactions that occur between plants and microorganisms in the soil, yet much remains to be learned about spatial and temporal variation in their production. This work outlines a method utilizing a novel colorimetric paper to detect spatial and temporal changes in the production of nitrogen-containing compounds on the root surface. While existing methods have made it possible to conduct detailed analysis of root exudate composition, relatively less is known about where in the root system exudates are produced and how this localization changes as the root grows. Furthermore, there is much to learn about how exudate localization and composition varies in response to stress. Root exudates are chemically diverse secretions composed of organic acids, amino acids, proteins, sugars, and other metabolites. The sensor utilized for the method, ninhydrin, is a colorless substance in solution that reacts with free amino groups to form a purple dye. A detection paper was developed by formulating ninhydrin into a print solution that was uniformly deposited onto paper with a commercial ink jet printer. This "ninhydrin paper" was used to analyze the chemical makeup of root surfaces from maize seedlings grown vertically on germination paper. Through contact between the ninhydrin paper and seedling root surfaces, combined with images of both the seedlings and dried ninhydrin papers captured using a standard flatbed scanner, nitrogen-containing substances on the root surface can be localized and concentration of signal estimated for over 2 weeks of development. The method was found to be non-inhibiting to plant growth over the analysis period although damage to root hairs was observed. The method is sensitive in the detection of free amines at concentrations as little as 140 μM. Furthermore, ninhydrin paper is stable, showing consistent color changes up to 2 weeks after printing. This relatively simple, low-cost method could contribute to a better understanding of root exudates and mechanisms used by plants to interact with the complex soil environment during growth and development.

A Low-Cost Imaging Method for the Temporal and Spatial Colorimetric Detection of Free Amines on Maize Root Surfaces.

Bacterial biofilms pose a significant health risk when they grow on devices placed or implanted in the human body. There is a need to develop new materials that can be used as surface coatings on such devices to inhibit biofilm growth. We report on measurements of the biofilm growth rate on a new polymeric material, slippery BMA-EDMA, which can be used as a surface coating for medical devices. Growth rate measurements are also reported for polycarbonate and glass surfaces, for comparison. Measurements are made in a medium shear stress fluid environment. The physical properties of the surfaces are characterized using contact angle, surface roughness, surface skewness and surface kurtosis. Growth rate on the slippery BMA-EDMA is found to be the smallest of the three surfaces. Growth rate is weakly correlated with surface hydrophobicity and surface roughness, while it is strongly correlated with surface skewness and kurtosis.

Growth Rate of  Biofilms on Slippery Butyl Methacrylate-Co-Ethylene Dimethacrylate (BMA-EDMA), Glass and Polycarbonate Surfaces.

Biofilms are microbial communities attached to a surface and embedded in an extracellular polymeric substance which provides for the protection, stability and nutrients of the various bacterial species indwelling. These communities can build up in a variety of different environments from industrial equipment to medical devices resulting in damage, loss of productivity and disease. They also have great potential for economic and societal benefits as bioremediation agents and renewable energy sources. The great potential benefits and threats of biofilms has encouraged researchers across disciplines to study biofilm characteristics and antibiofilm strategies resulting in chemists, physicists, material scientists, and engineers, to develop beneficial biofilm applications and prevention methods. The ultimate outcome is a wealth of knowledge and innovative technology. However, without extensive formal training in microbes and biofilm research, these scientists find a daunting array of established techniques for growing, quantifying and characterizing biofilms while trying to design experiments and develop innovative laboratory protocols. This mini-review focuses on enriching interdisciplinary efforts and understanding by overviewing a variety of quantitative and qualitative biofilm characterization methods to assist the novice researcher in assay selection. This review consists of four parts. Part 1 is a brief overview of biofilms and the unique properties that demand a highly interdisciplinary approach. Part 2 describes the classical quantification techniques including colony forming unit (CFU) counting and crystal violet staining, but also introduces some modern methods including ATP bioluminescence and quartz crystal microbalance. Part 3 focuses on the characterization of biofilm morphology and chemistry including scanning electron microscopy and spectroscopic methods. Finally, Part 4 illustrates the use of software, including ImageJ and predictive modeling platforms, for biofilm analysis. Each section highlights the most common methods, including literature references, to help novice biofilm researchers make choices which commensurate with their study goals, budget and available equipment.

Christina Wilson

Department of Chemistry

Doane University

Live Cell Analysis of Shear Stress on Pseudomonas aeruginosa Using an Automated Higher-Throughput Microfluidic System

Christina Wilson

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Department of Chemistry

Doane University

Live Cell Analysis of Shear Stress on Pseudomonas aeruginosa Using an Automated Higher-Throughput Microfluidic System

Department of Chemistry