High-resolution 3D mapping of rhizosphere glycan patterning using molecular probes in a transparent soil system

Rhizospheres are microecological zones at the interface of roots and soils. Interactions between bacteria and roots are critical for maintaining plant and soil health but are difficult to study because of constraints inherent in working with underground systems. We have developed an in-situ rhizosphere imaging system based on transparent soils and molecular probes that can be imaged using confocal microscopy. We observed spatial patterning of polysaccharides along roots and on cells deposited into the rhizosphere and also co-localised fluorescently tagged soil bacteria. These studies provide insight into the complex glycan landscape of rhizospheres and suggest a means by which root / rhizobacteria interactions can be non-disruptively studied

Dependence of cancer cell adhesion kinetics on integrin ligand surface density measured by a high-throughput label-free resonant waveguide grating biosensor

A novel high-throughput label-free resonant waveguide grating (RWG) imager biosensor, the Epic® BenchTop (BT), was utilized to determine the dependence of cell spreading kinetics on the average surface density (vRGD) of integrin ligand RGD-motifs. vRGD was tuned over four orders of magnitude by co-adsorbing the biologically inactive PLL-g-PEG and the RGD-functionalized PLL-g-PEG-RGD synthetic copolymers from their mixed solutions onto the sensor surface. Using highly adherent human cervical tumor (HeLa) cells as a model system, cell adhesion kinetic data of unprecedented quality were obtained. Spreading kinetics were fitted with the logistic equation to obtain the spreading rate constant (r) and the maximum biosensor response (Δλmax), which is assumed to be directly proportional to the maximum spread contact area (Amax). r was found to be independent of the surface density of integrin ligands. In contrast, Δλmax increased with increasing RGD surface density until saturation at high densities. Interpreting the latter behavior with a simple kinetic mass action model, a 2D dissociation constant of 1753 ± 243 μm−2 (corresponding to a 3D dissociation constant of ~30 μM) was obtained for the binding between RGD-specific integrins embedded in the cell membrane and PLL-g-PEG-RGD. All of these results were obtained completely noninvasively without using any labels

Metallographic examination of surveillance coupons from the Wilsonville, Alabama, Solvent Refined Coal Pilot Plant, 1977-1978

Commercialization of the solvent refined coal (SRC) process requires corrosion-resistant yet economical materials of construction. A corrosion surveillance program was initiated at the Wilsonville, Alabama, SRC pilot plant to expose racks of welded specimens of engineering alloys to the various process conditions in major plant vessels. To observe the long-term cumulative exposure effects, sections were taken from the specimens after six months. The coupons were replaced in the vessels for another year and then reexamined. These sections were evaluated at ORNL by standard procedures. Microprobe analyses were performed on the scale on selected specimens. The scale, both on and below the surface, proved to be varying complex mixtures of oxides and sulfides sometimes intermixed with process stream material. Weight change records indicate that corrosion was not a serious problem during these exposures, with the coals processed to date

Plant-environment microscopy tracks interactions of Bacillus subtilis with plant roots across the entire rhizosphere

Our understanding of plant–microbe interactions in soil is limited by the difficulty of observing processes at the microscopic scale throughout plants’ large volume of influence. Here, we present the development of three-dimensional live microscopy for resolving plant–microbe interactions across the environment of an entire seedling growing in a transparent soil in tailor-made mesocosms, maintaining physical conditions for the culture of both plants and microorganisms. A tailor-made, dual-illumination light sheet system acquired photons scattered from the plant while fluorescence emissions were simultaneously captured from transparent soil particles and labeled microorganisms, allowing the generation of quantitative data on samples ∼3,600 mm3 in size, with as good as 5 µm resolution at a rate of up to one scan every 30 min. The system tracked the movement of Bacillus subtilis populations in the rhizosphere of lettuce plants in real time, revealing previously unseen patterns of activity. Motile bacteria favored small pore spaces over the surface of soil particles, colonizing the root in a pulsatile manner. Migrations appeared to be directed toward the root cap, the point of “first contact,” before the subsequent colonization of mature epidermis cells. Our findings show that microscopes dedicated to live environmental studies present an invaluable tool to understand plant–microbe interactions

Birds in education: innovative learning methods for capacity building in nature conservation

The role of volunteer birdwatchers in bird censuses across the world is crucial to acquire data for science and conservation, and people with different skill specializations and motivations are engaged as citizen scientists. Bird species richness is positively related to life-satisfaction across Europe, while this association doesn’t exist in other wildlife groups. Therefore, birds seem to be particularly captivating for recruiting people to environmental monitoring and nature conservation efforts. The WildSkills EU Erasmus+ project identified a discrepancy at the European level between higher education training and the needs of the labour market in the field of environmental monitoring and nature conservation. To address this skills gap, a collaboration between professionals from European nongovernmental organizations and higher education institutions was set up to develop innovative and accessible distance learning. The project will use a virtual learning environment that combines the use of physical equipment and tools with webinars and livestream technologies, and periods of transnational mobility, to provide, assess, accredit, and support the acquisition of new knowledge. The Birds in Education course is part of the learning materials of the WildSkills EU project. This course will explore (1) the personal motivations for, and the implications to science and society, of our awareness of birds, (2) notions of bird conservation in the European context, (3) the basics of bird identification, (4) how to use birds as environmental education tools, and (5) digital tools for bird identification and citizen science. The course will be tested by higher education students from different backgrounds, aimed at developing skills for the nature conservation sector, and by professionals of the education sector. In the end, this course will contribute to capacity building and to citizen science and has the potential of increasing the public engagement in bird counts, which represents a growing need of many bird conservation organizations