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44 results on '"Shor, Leslie M."'

3. Chemotactic Bacteria Facilitate the Dispersion of Nonmotile Bacteria through Micrometer-Sized Pores in Engineered Porous Media

Author

Balseiro-Romero, María, Prieto-Fernández, Ángeles, Shor, Leslie M., Ghoshal, Subhasis, Baveye, Philippe C., Ortega-Calvo, José Julio, European Commission, Ministerio de Ciencia e Innovación (España), Agencia Estatal de Investigación (España), Balseiro-Romero, M., Prieto-Fernández, Ángeles, Ghoshal, S., Baveye, P., Ortega Calvo, J. J., Ministerio de Ciencia, Innovación (España), Balseiro-Romero, M. [0000-0003-0831-3899], Prieto-Fernández, Ángeles [0000-0003-2601-1528], Ghoshal, S. [0000-0001-9968-6150], Baveye, P. [0000-0002-8432-6141], and Ortega Calvo, J. J. [0000-0003-1672-5199]

Subjects
Chemotactic Factors, Pseudomonas putida, Chemotaxis, Bioaccessibility, General Chemistry, Microbe-microbe cotransport, Environmental Chemistry, Dimethylpolysiloxanes, Polycyclic Aromatic Hydrocarbons, Micrometer-sized pores, Porosity, Hexachlorocyclohexane, gamma-Aminobutyric Acid, Hitchhiking
Abstract

10 páginas.- 4 figuras.- 4 tablas.- 45 referencias.- The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.est.2c03149, Recent research has demonstrated that chemotactic bacteria can disperse inside microsized pores while traveling toward favorable conditions. Microbe–microbe cotransport might enable nonmotile bacteria to be carried with motile partners to enhance their dispersion and reduce their deposition in porous systems. The aim of this study was to demonstrate the enhancement in the dispersion of nonmotile bacteria (Mycobacterium gilvum VM552, a polycyclic aromatic hydrocarbon-degrader, and Sphingobium sp. D4, a hexachlorocyclohexane-degrader, through micrometer-sized pores near the exclusion-cell-size limit, in the presence of motile Pseudomonas putida G7 cells. For this purpose, we used bioreactors equipped with two chambers that were separated with membrane filters with 3, 5, and 12 μm pore sizes and capillary polydimethylsiloxane (PDMS) microarrays (20 μm × 35 μm × 2.2 mm). The cotransport of nonmotile bacteria occurred exclusively in the presence of a chemoattractant concentration gradient, and therefore, a directed flow of motile cells. This cotransport was more intense in the presence of larger pores (12 μm) and strong chemoeffectors (γ-aminobutyric acid). The mechanism that governed cotransport at the cell scale involved mechanical pushing and hydrodynamic interactions. Chemotaxis-mediated cotransport of bacterial degraders and its implications in pore accessibility opens new avenues for the enhancement of bacterial dispersion in porous media and the biodegradation of heterogeneously contaminated scenarios., This research was funded by European Union's Horizon 2020 research and innovation program under the Marie Sklodowska- Curie grant agreement no. 895340 (BIOTAC project) and by the Spanish Ministry of Science and Innovation (PID2019- 109700RB-C21) .

Published
2022

7. Piezoelectric Nanofiber Membrane for Reusable, Stable, and Highly Functional Face Mask Filter with Long‐Term Biodegradability

Author

Le, Thinh T., primary, Curry, Eli J., additional, Vinikoor, Tra, additional, Das, Ritopa, additional, Liu, Yang, additional, Sheets, Donal, additional, Tran, Khanh T. M., additional, Hawxhurst, Christopher J., additional, Stevens, James F., additional, Hancock, Jason N., additional, Bilal, Osama R., additional, Shor, Leslie M., additional, and Nguyen, Thanh D., additional

Published
2022
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18. Protozoan migration in bent microfluidic channels

Author

Wei Wang, Shor, Leslie M., LeBoeuf, Eugene J., Wikswo, John P., Taghon, Gary L., and Kosson, David S.

Subjects
Analysis of variance -- Usage, Ciliata -- Physiological aspects, Fluid dynamics -- Analysis, Biological sciences
Abstract

A study of the dispersal and swimming speed of marine ciliates in straight and bent microfluidic channels is described. The channel width and protozoan size along with the channel turning angle was found to significantly affect the dispersal rate and swimming speed of ciliate protozoas.

Published
2008

19. Mobility of protozoa through narrow channels

Author

Wei Wang, Shor, Leslie M., LeBoeuf, Eugene J., Wikswo, John P., and Kosson, David S.

Subjects
Protozoa -- Research, Marine ecology -- Research, Biological sciences
Abstract

The effect of spatial constraints on the mobility of six species of marine protozoa was investigated. The empirical results and qualitative observations help define the physical limitations on protozoan grazing, a critical process affecting microbes in the environment.

Published
2005

41. Microfluidic passive samplers for in situcollection of live aquatic protistsElectronic supplementary information (ESI) available: (1) Table S1, abundance of protists collected in field trials by deployment date and location. (2) Table S2, abundance of protists collected in field trials by sampler type. (3) Table S3, abundance of protists collected in laboratory trial with marine sediment. (4) Fig. S1, Cyclidiumsp. collected in laboratory trial using different microcosm concentrations. (5) Fig. S2, representative micrographs from fast-acquisition scanning of protists in galleries. (6) Movie M1, highly concentrated Cyclidiumsp. in laboratory enrichment study. (7) Movie M2, protist entering the narrow constriction of a square observation gallery. (8) Movie M3, multiple protists and a metazoan collected from the field in a heart-shaped observation gallery. (9) Movie M4, Parameciumsp. trapped within a heart-shaped observation gallery. (10) CAD1, computer aided design of photolithography mas

Author

Bouchillon, Grant M., Chau, Jessica Furrer, McManus, George B., and Shor, Leslie M.

Abstract

This paper describes the development of microfluidic passive samplers for the collection of live protists from natural aquatic habitats. Microfluidic passive samplers provide several potential benefits over existing sampling methods. For example, they offer greater versatility, higher throughput, and do not require the disruption of specimens through the use of fixatives, stains, or by extraction. In lab testing, a marine ciliate Cyclidiumsp. was concentrated from 600 cells per mL in a laboratory microcosm to above 2 × 108cells per mL within individual microfluidic observation galleries. In field experiments, live protists and other microorganisms were collected from surface water and sediment in a northeastern Connecticut stream. Protists were accumulated to 1 × 107cells per mL in individual observation galleries. Concentrating and isolating protists enables high-resolution, long-term observation of live, unstained protists. The compact arrangement of observation galleries facilitates high-throughput analysis. Sampler versions were created that differed in the degree of channel branching, the spatial density of galleries, and the size and shape of gallery entrance constrictions. Lab and field testing illustrated tradeoffs in performance among sampler variations in terms of the fraction of occupied chambers, overall on-chip biomass density, and in the types of protists and in the range of sizes of protists collected. Recommendations are provided to facilitate the adoption of microfluidic passive samplers for environmental characterization, research, and educational purposes.

Published
2014
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43. Application of microfluidic systems in modelling impacts of environmental structure on stress-sensing by individual microbial cells.

Author

Harvey HJ, Chubynsky MV, Sprittles JE, Shor LM, Mooney SJ, Wildman RD, and Avery SV

Abstract

Environmental structure describes physical structure that can determine heterogenous spatial distribution of biotic and abiotic (nutrients, stressors etc.) components of a microorganism's microenvironment. This study investigated the impact of micrometre-scale structure on microbial stress sensing, using yeast cells exposed to copper in microfluidic devices comprising either complex soil-like architectures or simplified environmental structures. In the soil micromodels, the responses of individual cells to inflowing medium supplemented with high copper (using cells expressing a copper-responsive pCUP1 -reporter fusion) could be described neither by spatial metrics developed to quantify proximity to environmental structures and surrounding space, nor by computational modelling of fluid flow in the systems. In contrast, the proximities of cells to structures did correlate with their responses to elevated copper in microfluidic chambers that contained simplified environmental structure. Here, cells within more open spaces showed the stronger responses to the copper-supplemented inflow. These insights highlight not only the importance of structure for microbial responses to their chemical environment, but also how predictive modelling of these interactions can depend on complexity of the system, even when deploying controlled laboratory conditions and microfluidics., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2021 The Authors.)

Published
2021
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44. Red blood cell classification in lensless single random phase encoding using convolutional neural networks.

Author

O'Connor T, Hawxhurst C, Shor LM, and Javidi B

Subjects
Animals, Cattle, Horses, Image Processing, Computer-Assisted, Imaging, Three-Dimensional instrumentation, Machine Learning, Erythrocytes classification, Holography instrumentation, Microfluidic Analytical Techniques instrumentation, Neural Networks, Computer, Optical Imaging instrumentation
Abstract

Rapid cell identification is achieved in a compact and field-portable system employing single random phase encoding to record opto-biological signatures of living biological cells of interest. The lensless, 3D-printed system uses a diffuser to encode the complex amplitude of the sample, then the encoded signal is recorded by a CMOS image sensor for classification. Removal of lenses in this 3D sensing system removes restrictions on the field of view, numerical aperture, and depth of field normally imposed by objective lenses in comparable microscopy systems to enable robust 3D capture of biological volumes. Opto-biological signatures for two classes of animal red blood cells, situated in a microfluidic device, are captured then input into a convolutional neural network for classification, wherein the AlexNet architecture, pretrained on the ImageNet database is used as the deep learning model. Video data was recorded of the opto-biological signatures for multiple samples, then each frame was treated as an input image to the network. The pre-trained network was fine-tuned and evaluated using a dataset of over 36,000 images. The results show improved performance in comparison to a previously studied Random Forest classification model using extracted statistical features from the opto-biological signatures. The system is further compared to and outperforms a similar shearing-based 3D digital holographic microscopy system for cell classification. In addition to improvements in classification performance, the use of convolutional neural networks in this work is further demonstrated to provide improved performance in the presence of noise. Red blood cell identification as presented here, may serve as a key step toward lensless pseudorandom phase encoding applications in rapid disease screening. To the best of our knowledge this is the first report of lensless cell identification in single random phase encoding using convolutional neural networks.

Published
2020
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