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Llamas A, Leon-Miranda E, Tejada-Jimenez M. Microalgal and Nitrogen-Fixing Bacterial Consortia: From Interaction to Biotechnological Potential. PLANTS (BASEL, SWITZERLAND) 2023; 12:2476. [PMID: 37447037 DOI: 10.3390/plants12132476] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 06/15/2023] [Accepted: 06/26/2023] [Indexed: 07/15/2023]
Abstract
Microalgae are used in various biotechnological processes, such as biofuel production due to their high biomass yields, agriculture as biofertilizers, production of high-value-added products, decontamination of wastewater, or as biological models for carbon sequestration. The number of these biotechnological applications is increasing, and as such, any advances that contribute to reducing costs and increasing economic profitability can have a significant impact. Nitrogen fixing organisms, often called diazotroph, also have great biotechnological potential, mainly in agriculture as an alternative to chemical fertilizers. Microbial consortia typically perform more complex tasks than monocultures and can execute functions that are challenging or even impossible for individual strains or species. Interestingly, microalgae and diazotrophic organisms are capable to embrace different types of symbiotic associations. Certain corals and lichens exhibit this symbiotic relationship in nature, which enhances their fitness. However, this relationship can also be artificially created in laboratory conditions with the objective of enhancing some of the biotechnological processes that each organism carries out independently. As a result, the utilization of microalgae and diazotrophic organisms in consortia is garnering significant interest as a potential alternative for reducing production costs and increasing yields of microalgae biomass, as well as for producing derived products and serving biotechnological purposes. This review makes an effort to examine the associations of microalgae and diazotrophic organisms, with the aim of highlighting the potential of these associations in improving various biotechnological processes.
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Affiliation(s)
- Angel Llamas
- Department of Biochemistry and Molecular Biology, Campus de Rabanales and Campus Internacional de Excelencia Agroalimentario (CeiA3), Edificio Severo Ochoa, University of Córdoba, 14071 Córdoba, Spain
| | - Esperanza Leon-Miranda
- Department of Biochemistry and Molecular Biology, Campus de Rabanales and Campus Internacional de Excelencia Agroalimentario (CeiA3), Edificio Severo Ochoa, University of Córdoba, 14071 Córdoba, Spain
| | - Manuel Tejada-Jimenez
- Department of Biochemistry and Molecular Biology, Campus de Rabanales and Campus Internacional de Excelencia Agroalimentario (CeiA3), Edificio Severo Ochoa, University of Córdoba, 14071 Córdoba, Spain
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Valentino M, Sirico DG, Memmolo P, Miccio L, Bianco V, Ferraro P. Digital holographic approaches to the detection and characterization of microplastics in water environments. APPLIED OPTICS 2023; 62:D104-D118. [PMID: 37132775 DOI: 10.1364/ao.478700] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Microplastic (MP) pollution is seriously threatening the environmental health of the world, which has accelerated the development of new identification and characterization methods. Digital holography (DH) is one of the emerging tools to detect MPs in a high-throughput flow. Here, we review advances in MP screening by DH. We examine the problem from both the hardware and software viewpoints. Automatic analysis based on smart DH processing is reported by highlighting the role played by artificial intelligence for classification and regression tasks. In this framework, the continuous development and availability in recent years of field-portable holographic flow cytometers for water monitoring also is discussed.
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Barua R, Sanborn D, Nyman L, McFarland M, Moore T, Hong J, Garrett M, Nayak AR. In situ digital holographic microscopy for rapid detection and monitoring of the harmful dinoflagellate, Karenia brevis. HARMFUL ALGAE 2023; 123:102401. [PMID: 36894209 DOI: 10.1016/j.hal.2023.102401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 12/09/2022] [Accepted: 02/03/2023] [Indexed: 06/18/2023]
Abstract
Karenia brevis blooms, also known as red tide, are a recurring problem in the coastal Gulf of Mexico. These blooms have the capacity to inflict substantial damage to human and animal health as well as local economies. Thus, monitoring and detection of K. brevis blooms at all life stages and cell concentrations is essential for ensuring public safety. Current K. brevis monitoring methods have several limitations, including size resolution limits and concentration ranges, limited capacity for spatial and temporal profiling, and/or small sample volume processing. Here, a novel monitoring method wherein an autonomous digital holographic imaging microscope (AUTOHOLO), that overcomes these limitations and can characterize K. brevis concentrations in situ, is presented. Using the AUTOHOLO, in situ field measurements were conducted in the coastal Gulf of Mexico during an active K. brevis bloom over the 2020-21 winter season. Surface and sub-surface water samples collected during these field studies were also analyzed in the lab using benchtop holographic imaging and flow cytometry for validation. A convolutional neural network was trained for automated classification of K. brevis at all concentration ranges. The network was validated with manual counts and flow cytometry, yielding a 90% accuracy across diverse datasets with varying K. brevis concentrations. The usefulness of pairing the AUTOHOLO with a towing system was also demonstrated for characterizing particle abundance over large spatial distances, which could potentially facilitate characterization of spatial distributions of K. brevis during bloom events. Future applications of the AUTOHOLO can include integration into existing HAB monitoring networks to enhance detection capabilities for K. brevis in aquatic environments around the world.
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Affiliation(s)
- Ranjoy Barua
- Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, 33431, FL United States of America; Harbor Branch Oceanographic Institute, Florida Atlantic University, Fort Pierce, 34946, FL United States of America
| | - Delaney Sanborn
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, 55455, MN United States of America; St. Anthony Falls Laboratory, University of Minnesota, Minneapolis, 55455, MN United States of America
| | - Lisa Nyman
- Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, 33431, FL United States of America; Harbor Branch Oceanographic Institute, Florida Atlantic University, Fort Pierce, 34946, FL United States of America
| | - Malcolm McFarland
- Harbor Branch Oceanographic Institute, Florida Atlantic University, Fort Pierce, 34946, FL United States of America
| | - Timothy Moore
- Harbor Branch Oceanographic Institute, Florida Atlantic University, Fort Pierce, 34946, FL United States of America
| | - Jiarong Hong
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, 55455, MN United States of America; St. Anthony Falls Laboratory, University of Minnesota, Minneapolis, 55455, MN United States of America
| | - Matt Garrett
- Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, St. Petersburg, 33701, FL United States of America
| | - Aditya R Nayak
- Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, 33431, FL United States of America; Harbor Branch Oceanographic Institute, Florida Atlantic University, Fort Pierce, 34946, FL United States of America.
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Flores E, Romanovicz DK, Nieves-Morión M, Foster RA, Villareal TA. Adaptation to an Intracellular Lifestyle by a Nitrogen-Fixing, Heterocyst-Forming Cyanobacterial Endosymbiont of a Diatom. Front Microbiol 2022; 13:799362. [PMID: 35369505 PMCID: PMC8969518 DOI: 10.3389/fmicb.2022.799362] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 02/22/2022] [Indexed: 11/13/2022] Open
Abstract
The symbiosis between the diatom Hemiaulus hauckii and the heterocyst-forming cyanobacterium Richelia intracellularis makes an important contribution to new production in the world's oceans, but its study is limited by short-term survival in the laboratory. In this symbiosis, R. intracellularis fixes atmospheric dinitrogen in the heterocyst and provides H. hauckii with fixed nitrogen. Here, we conducted an electron microscopy study of H. hauckii and found that the filaments of the R. intracellularis symbiont, typically composed of one terminal heterocyst and three or four vegetative cells, are located in the diatom's cytoplasm not enclosed by a host membrane. A second prokaryotic cell was also detected in the cytoplasm of H. hauckii, but observations were infrequent. The heterocysts of R. intracellularis differ from those of free-living heterocyst-forming cyanobacteria in that the specific components of the heterocyst envelope seem to be located in the periplasmic space instead of outside the outer membrane. This specialized arrangement of the heterocyst envelope and a possible association of the cyanobacterium with oxygen-respiring mitochondria may be important for protection of the nitrogen-fixing enzyme, nitrogenase, from photosynthetically produced oxygen. The cell envelope of the vegetative cells of R. intracellularis contained numerous membrane vesicles that resemble the outer-inner membrane vesicles of Gram-negative bacteria. These vesicles can export cytoplasmic material from the bacterial cell and, therefore, may represent a vehicle for transfer of fixed nitrogen from R. intracellularis to the diatom's cytoplasm. The specific morphological features of R. intracellularis described here, together with its known streamlined genome, likely represent specific adaptations of this cyanobacterium to an intracellular lifestyle.
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Affiliation(s)
- Enrique Flores
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC, Universidad de Sevilla, Seville, Spain
| | - Dwight K Romanovicz
- Department of Psychology, The University of Texas at Austin, Austin, TX, United States
| | - Mercedes Nieves-Morión
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC, Universidad de Sevilla, Seville, Spain
| | - Rachel A Foster
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
| | - Tracy A Villareal
- Department of Marine Science and Marine Science Institute, The University of Texas at Austin, Port Aransas, TX, United States
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Abstract
Nitrogen fixation, the reduction of atmospheric dinitrogen gas (N2) to ammonia, is critical for biological productivity but is difficult to study in the vast expanse of the global ocean. Decades of field studies and the infusion of molecular biological, genomic, isotopic, and geochemical modeling approaches have led to new paradigms and questions. The discovery of previously unknown N2-fixing (diazotrophic) microorganisms and unusual physiological adaptations, combined with diagnostic distributions of nutrients and their isotopes as well as measured and modeled biogeographic patterns, have revolutionized our understanding of marine N2 fixation and its role in the global nitrogen cycle. Anthropogenic upper-ocean warming, increased dissolved carbon dioxide, and acidification will affect the distribution and relative importance of specific subgroups of N2 fixers in the sea; these changes have implications for foodwebs and biogeochemical cycles.
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Affiliation(s)
- Jonathan P. Zehr
- Department of Ocean Sciences, University of California, Santa Cruz, CA 95003, USA
| | - Douglas G. Capone
- Marine and Environmental Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
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