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Pérez-Villagrán K, Martínez-Prado MA, Núñez-Ramírez DM, Medina-Torres L, Rojas-Contreras JA, Cabrales-González AM. Evaluation of functional characteristics of Acidithiobacillus thiooxidans microencapsulated in gum arabic by spray-drying as biotechnological tool in the mining industry. Arch Microbiol 2024; 206:320. [PMID: 38907882 DOI: 10.1007/s00203-024-04041-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2024] [Revised: 05/30/2024] [Accepted: 06/09/2024] [Indexed: 06/24/2024]
Abstract
The mining and metallurgical industry represents one of the leading causes of environmental pollution. In this context, the optimization of mineral waste management and the efficient extraction of metals of interest becomes an imperative priority for a sustainable future. Microorganisms such as Acidithiobacillus thiooxidans have represented a sustainable and economical alternative in recent years due to their capacity for environmental remediation in bioleaching processes because of their sulfur-oxidizing capacity and sulfuric acid generation. However, its use has been limited due to the reluctance of mine operators because of the constant reproduction of the bacterial culture in suitable media and the care that this entails. In this work, the central objective was to evaluate the functional characteristics of A. thiooxidans, microencapsulated and stored at room temperature for three years in vacuum bags, using a spray drying process with gum arabic as a wall vector. Growth kinetics showed a survival of 80 ± 0.52% after this long period of storage. Also, a qualitative fluorescence technique with a 5-cyano-2-3 ditolyl tetrazolium (CTC) marker was used to determine the respiratory activity of the microorganisms as soon as it was resuspended. On the other hand, the consumption of resuspended sulfur was evaluated to corroborate the correct metabolic functioning of the bacteria, with results of up to 50% sulfur reduction in 16 days and sulfate generation of 513.85 ± 0.4387 ppm and 524.15 ± 0.567 ppm for microencapsulated and non-microencapsulated cultures, respectively. These results demonstrate the success after three years of the microencapsulation process and give guidelines for its possible application in the mining-metallurgical industry.
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Affiliation(s)
- Karla Pérez-Villagrán
- Departamento de Ingenierías Química y Bioquímica, Tecnológico Nacional de México - Instituto Tecnológico de Durango (TecNM - ITD), Durango, Dgo, 34080, México
| | - María Adriana Martínez-Prado
- Departamento de Ingenierías Química y Bioquímica, Tecnológico Nacional de México - Instituto Tecnológico de Durango (TecNM - ITD), Durango, Dgo, 34080, México.
| | - Diola Marina Núñez-Ramírez
- Universidad Juárez del Estado de Durango - Facultad de Ciencias Químicas (UJED - FCQ), Durango, Dgo, 34120, México.
| | - Luis Medina-Torres
- Universidad Nacional Autónoma de México - Facultad Química (UNAM - FQ), Coyoacán, Ciudad de México, 04510, México
| | - Juan Antonio Rojas-Contreras
- Departamento de Ingenierías Química y Bioquímica, Tecnológico Nacional de México - Instituto Tecnológico de Durango (TecNM - ITD), Durango, Dgo, 34080, México
| | - Angel Manuel Cabrales-González
- Departamento de Ingenierías Química y Bioquímica, Tecnológico Nacional de México - Instituto Tecnológico de Durango (TecNM - ITD), Durango, Dgo, 34080, México
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Bormans M, Legrand B, Waisbord N, Briand E. Morphological and physiological impacts of salinity on colonial strains of the cyanobacteria Microcystis aeruginosa. Microbiologyopen 2023; 12:e1367. [PMID: 37379426 DOI: 10.1002/mbo3.1367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 06/05/2023] [Accepted: 06/07/2023] [Indexed: 06/30/2023] Open
Abstract
In the context of global change and enhanced toxic cyanobacterial blooms, cyanobacterial transfer to estuaries is likely to increase in frequency and intensity and impact animal and human health. Therefore, it is important to evaluate the potential of their survival in estuaries. In particular, we tested if the colonial form generally observed in natural blooms enhanced the resistance to salinity shock compared to the unicellular form generally observed in isolated strains. We tested the impact of salinity on two colonial strains of Microcystis aeruginosa, producing different amounts of mucilage by combining classical batch methods with a novel microplate approach. We demonstrate that the collective organization of these pluricellular colonies improves their ability to cope with osmotic shock when compared to unicellular strains. The effect of a sudden high salinity increase (S ≥ 20) over 5 to 6 days had several impacts on the morphology of M. aeruginosa colonies. For both strains, we observed a gradual increase in colony size and a gradual decrease in intercellular spacing. For one strain, we also observed a decrease in cell diameter with an increase in mucilage extent. The pluricellular colonies formed by both strains could withstand higher salinities than unicellular strains studied previously. In particular, the strain producing more mucilage displayed a sustained autofluorescence even at S = 20, a limit that is higher than the most robust unicellular strain. These results imply survival and possible M. aeruginosa proliferation in mesohaline estuaries.
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Affiliation(s)
- Myriam Bormans
- UMR CNRS 6553 ECOBIO, University of Rennes, Rennes, Cedex, France
| | - Benjamin Legrand
- UMR CNRS 6553 ECOBIO, University of Rennes, Rennes, Cedex, France
| | - Nicolas Waisbord
- UMR CNRS 6118 Géosciences Rennes, University of Rennes, Rennes, Cedex, France
| | - Enora Briand
- IFREMER, PHYTOX, Laboratoire GENALG, Nantes, France
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Witthohn M, Strieth D, Kollmen J, Schwarz A, Ulber R, Muffler K. Process Technologies of Cyanobacteria. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2022. [PMID: 36571615 DOI: 10.1007/10_2022_214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Although the handling and exploitation of cyanobacteria is associated with some challenges, these phototrophic bacteria offer great opportunities for innovative biotechnological processes. This chapter covers versatile aspects of working with cyanobacteria, starting with up-to-date in silico and in vitro screening methods for bioactive substances. Subsequently, common conservation techniques and vitality/viability estimation methods are compared and supplemented by own data regarding the non-invasive vitality evaluation via pulse amplitude modulated fluorometry. Moreover, novel findings about the influence the state of the pre-cultures have on main cultures are presented. The following sub-chapters deal with different photobioreactor-designs, with special regard to biofilm photobioreactors, as well as with heterotrophic and mixotrophic cultivation modes. The latter topic provides information from literature on successfully enhanced cyanobacterial production processes, augmented by own data.
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Affiliation(s)
- Marco Witthohn
- Department of Life Sciences and Engineering, University of Applied Sciences Bingen, Bingen, Germany
| | - Dorina Strieth
- Chair of Bioprocess Engineering, Technical University of Kaiserslautern, Kaiserslautern, Germany
| | - Jonas Kollmen
- Chair of Bioprocess Engineering, Technical University of Kaiserslautern, Kaiserslautern, Germany
| | - Anna Schwarz
- Department of Life Sciences and Engineering, University of Applied Sciences Bingen, Bingen, Germany
| | - Roland Ulber
- Chair of Bioprocess Engineering, Technical University of Kaiserslautern, Kaiserslautern, Germany.
| | - Kai Muffler
- Department of Life Sciences and Engineering, University of Applied Sciences Bingen, Bingen, Germany
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4
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To Die or Not to Die—Regulated Cell Death and Survival in Cyanobacteria. Microorganisms 2022; 10:microorganisms10081657. [PMID: 36014075 PMCID: PMC9415839 DOI: 10.3390/microorganisms10081657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/06/2022] [Accepted: 08/12/2022] [Indexed: 11/24/2022] Open
Abstract
Regulated cell death (RCD) is central to the development, integrity, and functionality of multicellular organisms. In the last decade, evidence has accumulated that RCD is a universal phenomenon in all life domains. Cyanobacteria are of specific interest due to their importance in aquatic and terrestrial habitats and their role as primary producers in global nutrient cycling. Current knowledge on cyanobacterial RCD is based mainly on biochemical and morphological observations, often by methods directly transferred from vertebrate research and with limited understanding of the molecular genetic basis. However, the metabolism of different cyanobacteria groups relies on photosynthesis and nitrogen fixation, whereas mitochondria are the central executioner of cell death in vertebrates. Moreover, cyanobacteria chosen as biological models in RCD studies are mainly colonial or filamentous multicellular organisms. On the other hand, unicellular cyanobacteria have regulated programs of cellular survival (RCS) such as chlorosis and post-chlorosis resuscitation. The co-existence of different genetically regulated programs in cyanobacterial populations may have been a top engine in life diversification. Development of cyanobacteria-specific methods for identification and characterization of RCD and wider use of single-cell analysis combined with intelligent image-based cell sorting and metagenomics would shed more light on the underlying molecular mechanisms and help us to address the complex colonial interactions during these events. In this review, we focus on the functional implications of RCD in cyanobacterial communities.
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Hartmann FSF, Udugama IA, Seibold GM, Sugiyama H, Gernaey KV. Digital models in biotechnology: Towards multi-scale integration and implementation. Biotechnol Adv 2022; 60:108015. [PMID: 35781047 DOI: 10.1016/j.biotechadv.2022.108015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 06/03/2022] [Accepted: 06/27/2022] [Indexed: 12/28/2022]
Abstract
Industrial biotechnology encompasses a large area of multi-scale and multi-disciplinary research activities. With the recent megatrend of digitalization sweeping across all industries, there is an increased focus in the biotechnology industry on developing, integrating and applying digital models to improve all aspects of industrial biotechnology. Given the rapid development of this field, we systematically classify the state-of-art modelling concepts applied at different scales in industrial biotechnology and critically discuss their current usage, advantages and limitations. Further, we critically analyzed current strategies to couple cell models with computational fluid dynamics to study the performance of industrial microorganisms in large-scale bioprocesses, which is of crucial importance for the bio-based production industries. One of the most challenging aspects in this context is gathering intracellular data under industrially relevant conditions. Towards comprehensive models, we discuss how different scale-down concepts combined with appropriate analytical tools can capture intracellular states of single cells. We finally illustrated how the efforts could be used to develop digitals models suitable for both cell factory design and process optimization at industrial scales in the future.
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Affiliation(s)
- Fabian S F Hartmann
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 223, 2800 Kgs. Lyngby, Denmark
| | - Isuru A Udugama
- Department of Chemical System Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, 113-8656 Tokyo, Japan; Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads, Building 228 A, 2800 Kgs. Lyngby, Denmark.
| | - Gerd M Seibold
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 223, 2800 Kgs. Lyngby, Denmark
| | - Hirokazu Sugiyama
- Department of Chemical System Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, 113-8656 Tokyo, Japan
| | - Krist V Gernaey
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads, Building 228 A, 2800 Kgs. Lyngby, Denmark.
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Heins A, Hoang MD, Weuster‐Botz D. Advances in automated real-time flow cytometry for monitoring of bioreactor processes. Eng Life Sci 2022; 22:260-278. [PMID: 35382548 PMCID: PMC8961054 DOI: 10.1002/elsc.202100082] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 10/22/2021] [Accepted: 10/27/2021] [Indexed: 12/18/2022] Open
Abstract
Flow cytometry and its technological possibilities have greatly advanced in the past decade as analysis tool for single cell properties and population distributions of different cell types in bioreactors. Along the way, some solutions for automated real-time flow cytometry (ART-FCM) were developed for monitoring of bioreactor processes without operator interference over extended periods with variable sampling frequency. However, there is still great potential for ART-FCM to evolve and possibly become a standard application in bioprocess monitoring and process control. This review first addresses different components of an ART-FCM, including the sampling device, the sample-processing unit, the unit for sample delivery to the flow cytometer and the settings for measurement of pre-processed samples. Also, available algorithms are presented for automated data analysis of multi-parameter fluorescence datasets derived from ART-FCM experiments. Furthermore, challenges are discussed for integration of fluorescence-activated cell sorting into an ART-FCM setup for isolation and separation of interesting subpopulations that can be further characterized by for instance omics-methods. As the application of ART-FCM is especially of interest for bioreactor process monitoring, including investigation of population heterogeneity and automated process control, a summary of already existing setups for these purposes is given. Additionally, the general future potential of ART-FCM is addressed.
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Affiliation(s)
- Anna‐Lena Heins
- Institute of Biochemical EngineeringTechnical University of MunichGarchingGermany
| | - Manh Dat Hoang
- Institute of Biochemical EngineeringTechnical University of MunichGarchingGermany
| | - Dirk Weuster‐Botz
- Institute of Biochemical EngineeringTechnical University of MunichGarchingGermany
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7
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Single-staining flow cytometry approach using SYTOX™ green to describe electroporation effects on Escherichia coli. Food Control 2022. [DOI: 10.1016/j.foodcont.2021.108488] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Zand E, Froehling A, Schoenher C, Zunabovic-Pichler M, Schlueter O, Jaeger H. Potential of Flow Cytometric Approaches for Rapid Microbial Detection and Characterization in the Food Industry-A Review. Foods 2021; 10:3112. [PMID: 34945663 PMCID: PMC8701031 DOI: 10.3390/foods10123112] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 11/14/2021] [Accepted: 11/16/2021] [Indexed: 12/11/2022] Open
Abstract
As microbial contamination is persistent within the food and bioindustries and foodborne infections are still a significant cause of death, the detection, monitoring, and characterization of pathogens and spoilage microorganisms are of great importance. However, the current methods do not meet all relevant criteria. They either show (i) inadequate sensitivity, rapidity, and effectiveness; (ii) a high workload and time requirement; or (iii) difficulties in differentiating between viable and non-viable cells. Flow cytometry (FCM) represents an approach to overcome such limitations. Thus, this comprehensive literature review focuses on the potential of FCM and fluorescence in situ hybridization (FISH) for food and bioindustry applications. First, the principles of FCM and FISH and basic staining methods are discussed, and critical areas for microbial contamination, including abiotic and biotic surfaces, water, and air, are characterized. State-of-the-art non-specific FCM and specific FISH approaches are described, and their limitations are highlighted. One such limitation is the use of toxic and mutagenic fluorochromes and probes. Alternative staining and hybridization approaches are presented, along with other strategies to overcome the current challenges. Further research needs are outlined in order to make FCM and FISH even more suitable monitoring and detection tools for food quality and safety and environmental and clinical approaches.
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Affiliation(s)
- Elena Zand
- Department of Food Science and Technology, Institute of Food Technology, University of Natural Resources and Life Sciences Vienna (BOKU), 1190 Vienna, Austria;
| | - Antje Froehling
- Leibniz Institute for Agricultural Engineering and Bioeconomy, Quality and Safety of Food and Feed, 14469 Potsdam, Germany; (A.F.); (O.S.)
| | - Christoph Schoenher
- Institute of Sanitary Engineering and Water Pollution Control, University of Natural Resources and Life Sciences, 1190 Vienna, Austria; (C.S.); (M.Z.-P.)
| | - Marija Zunabovic-Pichler
- Institute of Sanitary Engineering and Water Pollution Control, University of Natural Resources and Life Sciences, 1190 Vienna, Austria; (C.S.); (M.Z.-P.)
| | - Oliver Schlueter
- Leibniz Institute for Agricultural Engineering and Bioeconomy, Quality and Safety of Food and Feed, 14469 Potsdam, Germany; (A.F.); (O.S.)
| | - Henry Jaeger
- Department of Food Science and Technology, Institute of Food Technology, University of Natural Resources and Life Sciences Vienna (BOKU), 1190 Vienna, Austria;
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9
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González-Pleiter M, Velázquez D, Casero MC, Tytgat B, Verleyen E, Leganés F, Rosal R, Quesada A, Fernández-Piñas F. Microbial colonizers of microplastics in an Arctic freshwater lake. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 795:148640. [PMID: 34246139 DOI: 10.1016/j.scitotenv.2021.148640] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 06/03/2021] [Accepted: 06/20/2021] [Indexed: 05/12/2023]
Abstract
Microplastics (MPs) have been found everywhere as they are easily transported between environmental compartments. Through their transport, MPs are quickly colonized by microorganisms; this microbial community is known as the plastisphere. Here, we characterized the plastisphere of three MPs, one biodegradable (PHB) and two non-biodegradables (HDPE and LDPE), deployed in an Arctic freshwater lake for eleven days. The plastisphere was found to be complex, confirming that about a third of microbial colonizers were viable. Plastisphere was compared to microbial communities on the surrounding water and microbial mats on rocks at the bottom of the lake. Microbial mats followed by MPs showed the highest diversity regarding both prokaryotes and eukaryotes as compared to water samples; however, for fungi, MPs showed the highest diversity of the tested substrates. Significant differences on microbial assemblages on the three tested substrates were found; regarding microbial assemblages on MPs, bacterial genera found in polar environments such as Mycoplana, Erythromicrobium and Rhodoferax with species able to metabolize recalcitrant chemicals were abundant. Eukaryotic communities on MPs were characterized by the presence of ciliates of the genera Stentor, Vorticella and Uroleptus and the algae Cryptomonas, Chlamydomonas, Tetraselmis and Epipyxis. These ciliates normally feed on algae so that the complexity of these assemblages may serve to unravel trophic relationships between co-existing taxa. Regarding fungal communities on MPs, the most abundant genera were Betamyces, Cryptococcus, Arrhenia and Paranamyces. MPs, particularly HDPE, were enriched in the sulI and ermB antibiotic resistance genes (ARGs) which may raise concerns about human health-related issues as ARGs may be transferred horizontally between bacteria. This study highlights the importance of proper waste management and clean-up protocols to protect the environmental health of pristine environments such as polar regions in a context of global dissemination of MPs which may co-transport microorganisms, some of them including ARGs.
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Affiliation(s)
- Miguel González-Pleiter
- Departamento de Biología, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid, Spain
| | - David Velázquez
- Departamento de Biología, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid, Spain
| | - María Cristina Casero
- Departamento de Biogeoquímica y Ecología Microbiana, Museo Nacional de Ciencias Naturales, CSIC, E-28006 Madrid, Spain
| | - Bjorn Tytgat
- Laboratory of Protistology & Aquatic Ecology, Ghent University, Krijgslaan 281-S8, 9000 Gent, Belgium
| | - Elie Verleyen
- Laboratory of Protistology & Aquatic Ecology, Ghent University, Krijgslaan 281-S8, 9000 Gent, Belgium
| | - Francisco Leganés
- Departamento de Biología, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid, Spain
| | - Roberto Rosal
- Department of Chemical Engineering, University of Alcalá, E-28871 Alcalá de Henares, Madrid, Spain
| | - Antonio Quesada
- Departamento de Biología, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid, Spain
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Hejduková E, Nedbalová L. Experimental freezing of freshwater pennate diatoms from polar habitats. PROTOPLASMA 2021; 258:1213-1229. [PMID: 33909137 DOI: 10.1007/s00709-021-01648-8] [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: 01/20/2021] [Accepted: 04/08/2021] [Indexed: 06/12/2023]
Abstract
Diatoms are microalgae that thrive in a range of habitats worldwide including polar areas. Remarkably, non-marine pennate diatoms do not create any morphologically distinct dormant stages that could help them to successfully face unfavourable conditions. Their survival is probably connected with the adaptation of vegetative cells to freezing and desiccation. Here we assessed the freezing tolerance of vegetative cells and vegetative-looking resting cells of 12 freshwater strains of benthic pennate diatoms isolated from polar habitats. To test the effect of various environmental factors, the strains were exposed to -20 °C freezing in four differently treated cultures: (1) vegetative cells growing in standard conditions in standard WC medium and (2) resting cells induced by cold and dark acclimation and resting cells, where (3) phosphorus or (4) nitrogen deficiency were used in addition to cold and dark acclimation. Tolerance was evaluated by measurement of basal cell fluorescence of chlorophyll and determination of physiological cell status using a multiparameter fluorescent staining. Four strains out of 12 were able to tolerate freezing in at least some of the treatments. The minority of cells appeared to be active immediately after thawing process, while most cells were inactive, injured or dead. Overall, the results showed a high sensitivity of vegetative and resting cells to freezing stress among strains originating from polar areas. However, the importance of resting cells for survival was emphasized by a slight but statistically significant increase of freezing tolerance of nutrient-depleted cells. Low numbers of surviving cells in our experimental setup could indicate their importance for the overwintering of diatom populations in harsh polar conditions.
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Affiliation(s)
- Eva Hejduková
- Department of Ecology, Faculty of Science, Charles University, Viničná 7, 128 44, Prague 2, Czech Republic.
- Institute of Botany of the Czech Academy of Sciences, Dukelská 135, 379 82, Třeboň, Czech Republic.
| | - Linda Nedbalová
- Department of Ecology, Faculty of Science, Charles University, Viničná 7, 128 44, Prague 2, Czech Republic
- Institute of Botany of the Czech Academy of Sciences, Dukelská 135, 379 82, Třeboň, Czech Republic
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11
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Hare PJ, LaGree TJ, Byrd BA, DeMarco AM, Mok WWK. Single-Cell Technologies to Study Phenotypic Heterogeneity and Bacterial Persisters. Microorganisms 2021; 9:2277. [PMID: 34835403 PMCID: PMC8620850 DOI: 10.3390/microorganisms9112277] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 10/20/2021] [Accepted: 10/27/2021] [Indexed: 11/16/2022] Open
Abstract
Antibiotic persistence is a phenomenon in which rare cells of a clonal bacterial population can survive antibiotic doses that kill their kin, even though the entire population is genetically susceptible. With antibiotic treatment failure on the rise, there is growing interest in understanding the molecular mechanisms underlying bacterial phenotypic heterogeneity and antibiotic persistence. However, elucidating these rare cell states can be technically challenging. The advent of single-cell techniques has enabled us to observe and quantitatively investigate individual cells in complex, phenotypically heterogeneous populations. In this review, we will discuss current technologies for studying persister phenotypes, including fluorescent tags and biosensors used to elucidate cellular processes; advances in flow cytometry, mass spectrometry, Raman spectroscopy, and microfluidics that contribute high-throughput and high-content information; and next-generation sequencing for powerful insights into genetic and transcriptomic programs. We will further discuss existing knowledge gaps, cutting-edge technologies that can address them, and how advances in single-cell microbiology can potentially improve infectious disease treatment outcomes.
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Affiliation(s)
- Patricia J. Hare
- Department of Molecular Biology & Biophysics, UConn Health, Farmington, CT 06032, USA; (P.J.H.); (T.J.L.); (B.A.B.); (A.M.D.)
- School of Dental Medicine, University of Connecticut, Farmington, CT 06032, USA
| | - Travis J. LaGree
- Department of Molecular Biology & Biophysics, UConn Health, Farmington, CT 06032, USA; (P.J.H.); (T.J.L.); (B.A.B.); (A.M.D.)
| | - Brandon A. Byrd
- Department of Molecular Biology & Biophysics, UConn Health, Farmington, CT 06032, USA; (P.J.H.); (T.J.L.); (B.A.B.); (A.M.D.)
- School of Medicine, University of Connecticut, Farmington, CT 06032, USA
| | - Angela M. DeMarco
- Department of Molecular Biology & Biophysics, UConn Health, Farmington, CT 06032, USA; (P.J.H.); (T.J.L.); (B.A.B.); (A.M.D.)
| | - Wendy W. K. Mok
- Department of Molecular Biology & Biophysics, UConn Health, Farmington, CT 06032, USA; (P.J.H.); (T.J.L.); (B.A.B.); (A.M.D.)
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Jimel M, Kvíderová J, Elster J. Annual Cycle of Mat-Forming Filamentous Alga Tribonema cf. minus (Stramenopiles, Xanthophyceae) in Hydro-Terrestrial Habitats in the High Arctic Revealed By Multiparameter Fluorescent Staining. JOURNAL OF PHYCOLOGY 2021; 57:780-796. [PMID: 33244748 DOI: 10.1111/jpy.13109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/13/2020] [Accepted: 10/23/2020] [Indexed: 06/11/2023]
Abstract
The filamentous microalga Tribonema sp. (Stramenopiles, Xanthophyceae) plays an important role in shallow water polar (streams and seepages) and seasonally cold habitats in temperate regions (ponds). In these habitats, freezing and desiccation, and thus freeze-thawing and drying-rewetting cycles, are frequent. These regions produce visible biomass and are important components of low temperature-adapted communities. We characterized the annual cycles of a Tribonema cf. minus population in two habitats (seepage and stream) in the High Arctic, Svalbard. Seasonality, locality, and their combination (particularly changing environmental conditions) together with cultivation conditions of strains significantly affected their morphological characteristics. Morphological changes following hardening processes related to preparation for the winter period (transition from vegetative cells to akinete and/or pre-akinete) were recorded. Over the year, positive water temperatures (warmest 13.3°C) occurred for 5 months while negative (lowest temperature was -17.4°C) lasted for 7 months. In winter, there were two melt periods. Vitality staining protocol showed a high number of viable (77.4% and 53.8%) and dormant cells (1.7% and 4.1%; capable of growth and reproduction once suitable conditions return) in the winter seepage and stream, respectively. NPQ and OJIP chlorophyll fluorescence parameters revealed several hours recovery of photosynthesis (both field and control samples). During recovery, only minor or mild stress on photosynthesis was detected. FV /FM values (the photosynthetic efficiency of photosystem II in a dark-adapted state) in all field and control samples varied around 0.4. Tribonema cf. minus is capable of surviving winter Arctic conditions (perennial strategy).
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Affiliation(s)
- Matouš Jimel
- Faculty of Science, Charles University, Viničná 7, 12844, Prague 2, Czech Republic
| | - Jana Kvíderová
- Faculty of Science, University of South Bohemia, Na Zlaté Stoce 3, 370 05, České Budějovice, Czech Republic
- Institute of Botany, Czech Academy of Sciences, Dukelská 135, 379 82, Třeboň, Czech Republic
| | - Josef Elster
- Faculty of Science, University of South Bohemia, Na Zlaté Stoce 3, 370 05, České Budějovice, Czech Republic
- Institute of Botany, Czech Academy of Sciences, Dukelská 135, 379 82, Třeboň, Czech Republic
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Casero MC, Ascaso C, Quesada A, Mazur-Marzec H, Wierzchos J. Response of Endolithic Chroococcidiopsis Strains From the Polyextreme Atacama Desert to Light Radiation. Front Microbiol 2021; 11:614875. [PMID: 33537015 PMCID: PMC7848079 DOI: 10.3389/fmicb.2020.614875] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 12/28/2020] [Indexed: 01/09/2023] Open
Abstract
Cyanobacteria exposed to high solar radiation make use of a series of defense mechanisms, including avoidance, antioxidant systems, and the production of photoprotective compounds such as scytonemin. Two cyanobacterial strains of the genus Chroococcidiopsis from the Atacama Desert - which has one of the highest solar radiation levels on Earth- were examined to determine their capacity to protect themselves from direct photosynthetically active (PAR) and ultraviolet radiation (UVR): the UAM813 strain, originally isolated from a cryptoendolithic microhabitat within halite (NaCl), and UAM816 strain originally isolated from a chasmoendolithic microhabitat within calcite (CaCO3). The oxidative stress induced by exposure to PAR or UVR + PAR was determined to observe their short-term response, as were the long-term scytonemin production, changes in metabolic activity and ultrastructural damage induced. Both strains showed oxidative stress to both types of light radiation. The UAM813 strain showed a lower acclimation capacity than the UAM816 strain, showing an ever-increasing accumulation of reactive oxygen species (ROS) and a smaller accumulation of scytonemin. This would appear to reflect differences in the adaptation strategies followed to meet the demands of their different microhabitats.
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Affiliation(s)
- María Cristina Casero
- Grupo de Ecología y Geomicrobiología del Sustrato Lítico, Departamento de Biogeoquímica y Ecología Microbiana, Museo Nacional de Ciencias Naturales, CSIC, Madrid, Spain
| | - Carmen Ascaso
- Grupo de Ecología y Geomicrobiología del Sustrato Lítico, Departamento de Biogeoquímica y Ecología Microbiana, Museo Nacional de Ciencias Naturales, CSIC, Madrid, Spain
| | - Antonio Quesada
- Departamento de Biología, Universidad Autónoma de Madrid, Madrid, Spain
| | | | - Jacek Wierzchos
- Grupo de Ecología y Geomicrobiología del Sustrato Lítico, Departamento de Biogeoquímica y Ecología Microbiana, Museo Nacional de Ciencias Naturales, CSIC, Madrid, Spain
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14
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Mucci M, Guedes IA, Faassen EJ, Lürling M. Chitosan as a Coagulant to Remove Cyanobacteria Can Cause Microcystin Release. Toxins (Basel) 2020; 12:toxins12110711. [PMID: 33182627 PMCID: PMC7696597 DOI: 10.3390/toxins12110711] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/05/2020] [Accepted: 11/06/2020] [Indexed: 01/31/2023] Open
Abstract
Chitosan has been tested as a coagulant to remove cyanobacterial nuisance. While its coagulation efficiency is well studied, little is known about its effect on the viability of the cyanobacterial cells. This study aimed to test eight strains of the most frequent bloom-forming cyanobacterium, Microcystis aeruginosa, exposed to a realistic concentration range of chitosan used in lake restoration management (0 to 8 mg chitosan L-1). We found that after 1 h of contact with chitosan, in seven of the eight strains tested, photosystem II efficiency was decreased, and after 24 h, all the strains tested were affected. EC50 values varied from 0.47 to > 8 mg chitosan L-1 between the strains, which might be related to the amount of extracellular polymeric substances. Nucleic acid staining (Sytox-Green®) illustrated the loss of membrane integrity in all the strains tested, and subsequent leakage of pigments was observed, as well as the release of intracellular microcystin. Our results indicate that strain variability hampers generalization about species response to chitosan exposure. Hence, when used as a coagulant to manage cyanobacterial nuisance, chitosan should be first tested on the natural site-specific biota on cyanobacteria removal efficiency, as well as on cell integrity aspects.
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Affiliation(s)
- Maíra Mucci
- Aquatic Ecology and Water Quality Management Group, Department of Environmental Sciences, Wageningen University, Droevendaalsesteeg 3a, 6708 PB Wageningen, The Netherlands; (E.J.F.); (M.L.)
- Correspondence:
| | - Iame A. Guedes
- Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands;
| | - Elisabeth J. Faassen
- Aquatic Ecology and Water Quality Management Group, Department of Environmental Sciences, Wageningen University, Droevendaalsesteeg 3a, 6708 PB Wageningen, The Netherlands; (E.J.F.); (M.L.)
- Wageningen Food Safety Research, Wageningen Research, Akkermaalsbos 2, 6708 WB Wageningen, The Netherlands
| | - Miquel Lürling
- Aquatic Ecology and Water Quality Management Group, Department of Environmental Sciences, Wageningen University, Droevendaalsesteeg 3a, 6708 PB Wageningen, The Netherlands; (E.J.F.); (M.L.)
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15
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Hejduková E, Elster J, Nedbalová L. Annual Cycle of Freshwater Diatoms in the High Arctic Revealed by Multiparameter Fluorescent Staining. MICROBIAL ECOLOGY 2020; 80:559-572. [PMID: 32488483 DOI: 10.1007/s00248-020-01521-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 05/01/2020] [Indexed: 06/11/2023]
Abstract
Diatoms (Bacillariophyceae) are important primary producers in a wide range of hydro-terrestrial habitats in polar regions that are characterized by many extreme environmental conditions. Nevertheless, how they survive periods of drought and/or freeze remains unknown. A general strategy of microorganisms to overcome adverse conditions is dormancy, but morphologically distinct diatom resting stages are rare. This study aimed to evaluate the annual cycle of freshwater diatoms in the High Arctic (Central Spitsbergen) and provide an insight into their physiological cell status variability. The diversity and viability of diatom cells were studied in samples collected five times at four study sites, tracing the key events for survival (summer vegetative season, autumn dry-freezing, winter freezing, spring melting, summer vegetative season [again]). For viability evaluation, a multiparameter fluorescent staining was used in combination with light microscopy and allowed to reveal the physiological status at a single-cell level. The proportions of the cell categories were seasonally and locality dependent. The results suggested that a significant portion of vegetative cells survive winter and provide an inoculum for the following vegetative season. The ice thickness significantly influenced spring survival. The thicker the ice layer was, the more dead cells and fewer other stages were observed. The influence of the average week max-min temperature differences in autumn and winter was not proven.
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Affiliation(s)
- Eva Hejduková
- Department of Ecology, Faculty of Science, Charles University, Viničná 7, 128 44, Prague 2, Czech Republic.
| | - Josef Elster
- Institute of Botany of the Czech Academy of Sciences, Dukelská 135, 379 82, Třeboň, Czech Republic
- Centre for Polar Ecology, Faculty of Science, University of South Bohemia, Na Zlaté stoce 3, 370 05, České Budějovice, Czech Republic
| | - Linda Nedbalová
- Department of Ecology, Faculty of Science, Charles University, Viničná 7, 128 44, Prague 2, Czech Republic
- Institute of Botany of the Czech Academy of Sciences, Dukelská 135, 379 82, Třeboň, Czech Republic
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16
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Gacitua M, Urrejola C, Carrasco J, Vicuña R, Srain BM, Pantoja-Gutiérrez S, Leech D, Antiochia R, Tasca F. Use of a Thermophile Desiccation-Tolerant Cyanobacterial Culture and Os Redox Polymer for the Preparation of Photocurrent Producing Anodes. Front Bioeng Biotechnol 2020; 8:900. [PMID: 32974292 PMCID: PMC7471869 DOI: 10.3389/fbioe.2020.00900] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 07/13/2020] [Indexed: 12/25/2022] Open
Abstract
Oxygenic photosynthesis conducted by cyanobacteria has dramatically transformed the geochemistry of our planet. These organisms have colonized most habitats, including extreme environments such as the driest warm desert on Earth: the Atacama Desert. In particular, cyanobacteria highly tolerant to desiccation are of particular interest for clean energy production. These microorganisms are promising candidates for designing bioelectrodes for photocurrent generation owing to their ability to perform oxygenic photosynthesis and to withstand long periods of desiccation. Here, we present bioelectrochemical assays in which graphite electrodes were modified with the extremophile cyanobacterium Gloeocapsopsis sp. UTEXB3054 for photocurrent generation. Optimum working conditions for photocurrent generation were determined by modifying directly graphite electrode with the cyanobacterial culture (direct electron transfer), as well as using an Os polymer redox mediator (mediated electron transfer). Besides showing outstanding photocurrent production for Gloeocapsopsis sp. UTEXB3054, both in direct and mediated electron transfer, our results provide new insights into the metabolic basis of photocurrent generation and the potential applications of such an assisted bioelectrochemical system in a worldwide scenario in which clean energies are imperative for sustainable development.
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Affiliation(s)
- Manuel Gacitua
- Departamento de Química de los Materiales, Facultad de Quiìmica y Biologiìa, Universidad de Santiago de Chile, Santiago, Chile
| | - Catalina Urrejola
- Departamento Genética Molecular y Microbiología, Facultad Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Javiera Carrasco
- Departamento de Química de los Materiales, Facultad de Quiìmica y Biologiìa, Universidad de Santiago de Chile, Santiago, Chile
| | - Rafael Vicuña
- Departamento Genética Molecular y Microbiología, Facultad Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Benjamín M Srain
- Departamento de Oceanografía and Centro de Investigación Oceanográfica COPAS Sur-Austral, Universidad de Concepción, Concepción, Chile
| | - Silvio Pantoja-Gutiérrez
- Departamento de Oceanografía and Centro de Investigación Oceanográfica COPAS Sur-Austral, Universidad de Concepción, Concepción, Chile
| | - Donal Leech
- School of Chemistry and Ryan Institute, National University of Ireland Galway, Galway, Ireland
| | - Riccarda Antiochia
- Department of Chemistry and Drug Technologies, Sapienza University of Rome, Rome, Italy
| | - Federico Tasca
- Departamento de Química de los Materiales, Facultad de Quiìmica y Biologiìa, Universidad de Santiago de Chile, Santiago, Chile
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17
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Khan S, Zada S, Ahmad S, Lv J, Fu P. Concurrent biomineralization of silver ions into Ag 0 and Ag xO by Leptolyngbya strain JSC-1 and the establishment of its axenic culture. CHEMOSPHERE 2019; 215:693-702. [PMID: 30347364 DOI: 10.1016/j.chemosphere.2018.10.091] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 10/06/2018] [Accepted: 10/15/2018] [Indexed: 06/08/2023]
Abstract
Ionic silver is a potential hazard to aquatic life forms because of the increasing usage of silver based materials. The need for developing a sustainable and ecofriendly process to minimize the toxic effects of the free ions burden is now a scientific consensus. Therefore, we report the latest results in cyanobacterium Leptolyngbya JSC-1 investigating the tolerance towards toxic doses of silver, its extracellular biomineralization and silver nano-deposits formation inside the cells, and speculate about potential environmental impacts. In this study, scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS) analysis reveal the extracellular biomineralization of soluble silver (1-100 μM) into corresponding nanoparticles (50-100 nm in diameter) by JSC-1, while X-ray photoelectron spectroscopy (XPS) examination divulged the presence of both Ag+ and Ag0 in extracellularly biomineralized silver, depicting a mixture of both AgxO and elemental Ag. The scanning transmission electron microscopy (STEM), EDS and elemental mapping visualized the formation of intracellular silver nanoparticles. Moreover, this feature of silver tolerance in JSC-1 was further exploited and a novel protocol was developed for isolation and maintenance of axenic culture of this filamentous cyanobacterium. Consequently, this capability of silver biomineralization by JSC-1, both extra- and intra-cellularly might be useful for modeling the Ag resistance mechanism in cyanobacteria and also might be a sustainable alternative for heavy metals bioremediation in aquatic environments.
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Affiliation(s)
- Sikandar Khan
- College of Life Science and Technology, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing, 100029, China; Department of Biotechnology, Shaheed Benazir Bhutto University, Sheringal, KPK, Pakistan.
| | - Shah Zada
- College of Life Science and Technology, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing, 100029, China.
| | - Shahbaz Ahmad
- College of Life Science and Technology, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing, 100029, China.
| | - Jing Lv
- State Key Laboratory of Heavy Oil Processing, Institute of New Energy, China University of Petroleum, Beijing, 102249, China.
| | - Pengcheng Fu
- College of Life Science and Technology, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing, 100029, China; Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, 100029, China.
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18
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Safety Aspect of Enterococcus faecium FL31 Strain and Antibacterial Mechanism of Its Hydroxylated Bacteriocin BacFL31 against Listeria monocytogenes. BIOMED RESEARCH INTERNATIONAL 2018; 2018:5308464. [PMID: 30515405 PMCID: PMC6236939 DOI: 10.1155/2018/5308464] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 10/09/2018] [Indexed: 11/17/2022]
Abstract
In previous work we have isolated and identified a new strain called Enterococcus faecium FL31. The active compound secreted by this strain, "BacFL31", has been purified and characterized. In the present study, safety aspect, assessed by microbiological and molecular tests, demonstrated that Enterococcus faecium FL31 was susceptible to relevant antibiotics, free of hemolytic, gelatinase, DNase, and lipase activities. In addition, it did not harbor virulence and antibiotic resistance genes. Combined SYTOX Green dye and UV-absorbing experiments, along with released extracellular potassium and transmembrane electrical potential measurements, showed that pure BacFL31 at a concentration of 1×MIC (50 μg/mL) could damage cytoplasmic membrane of the pathogen Listeria monocytogenes ATCC19117. The same concentration causes the leakage of its intracellular constituents and leads to the destruction of this pathogenic microorganism. In summary, this work reflected characteristics of Enterococcus faecium FL31 strain and its bacteriocin in terms of functional and safety perspectives.
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19
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Heins AL, Weuster-Botz D. Population heterogeneity in microbial bioprocesses: origin, analysis, mechanisms, and future perspectives. Bioprocess Biosyst Eng 2018. [PMID: 29541890 DOI: 10.1007/s00449-018-1922-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Population heterogeneity is omnipresent in all bioprocesses even in homogenous environments. Its origin, however, is only so well understood that potential strategies like bet-hedging, noise in gene expression and division of labour that lead to population heterogeneity can be derived from experimental studies simulating the dynamics in industrial scale bioprocesses. This review aims at summarizing the current state of the different parts of single cell studies in bioprocesses. This includes setups to visualize different phenotypes of single cells, computational approaches connecting single cell physiology with environmental influence and special cultivation setups like scale-down reactors that have been proven to be useful to simulate large-scale conditions. A step in between investigation of populations and single cells is studying subpopulations with distinct properties that differ from the rest of the population with sub-omics methods which are also presented here. Moreover, the current knowledge about population heterogeneity in bioprocesses is summarized for relevant industrial production hosts and mixed cultures, as they provide the unique opportunity to distribute metabolic burden and optimize production processes in a way that is impossible in traditional monocultures. In the end, approaches to explain the underlying mechanism of population heterogeneity and the evidences found to support each hypothesis are presented. For instance, population heterogeneity serving as a bet-hedging strategy that is used as coordinated action against bioprocess-related stresses while at the same time spreading the risk between individual cells as it ensures the survival of least a part of the population in any environment the cells encounter.
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Affiliation(s)
- Anna-Lena Heins
- Institute of Biochemical Engineering, Technical University of Munich, Boltzmannstr. 15, 85748, Garching, Germany.
| | - Dirk Weuster-Botz
- Institute of Biochemical Engineering, Technical University of Munich, Boltzmannstr. 15, 85748, Garching, Germany
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20
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Mucci M, Noyma NP, de Magalhães L, Miranda M, van Oosterhout F, Guedes IA, Huszar VLM, Marinho MM, Lürling M. Chitosan as coagulant on cyanobacteria in lake restoration management may cause rapid cell lysis. WATER RESEARCH 2017; 118:121-130. [PMID: 28423343 DOI: 10.1016/j.watres.2017.04.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 04/07/2017] [Accepted: 04/08/2017] [Indexed: 06/07/2023]
Abstract
Combining coagulant and ballast to remove cyanobacteria from the water column is a promising restoration technique to mitigate cyanobacterial nuisance in surface waters. The organic, biodegradable polymer chitosan has been promoted as a coagulant and is viewed as non-toxic. In this study, we show that chitosan may rapidly compromise membrane integrity and kill certain cyanobacteria leading to release of cell contents in the water. A strain of Cylindrospermopsis raciborskii and one strain of Planktothrix agardhii were most sensitive. A 1.3 h exposure to a low dose of 0.5 mg l-1 chitosan already almost completely killed these cultures resulting in release of cell contents. After 24 h, reductions in PSII efficiencies of all cyanobacteria tested were observed. EC50 values varied from around 0.5 mg l-1 chitosan for the two sensitive strains, via about 5 mg l-1 chitosan for an Aphanizomenon flos-aquae strain, a toxic P. agardhii strain and two Anabaena cylindrica cultures, to more than 8 mg l-1 chitosan for a Microcystis aeruginosa strain and another A. flos-aquae strain. Differences in sensitivity to chitosan might be related to polymeric substances that surround cyanobacteria. Rapid lysis of toxic strains is likely and when chitosan flocking and sinking of cyanobacteria is considered in lake restoration, flocculation efficacy studies should be complemented with investigation on the effects of chitosan on the cyanobacteria assemblage being targeted.
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Affiliation(s)
- Maíra Mucci
- Aquatic Ecology & Water Quality Management Group, Department of Environmental Sciences, Wageningen University, P.O. Box 47, 6700 AA, Wageningen, The Netherlands.
| | - Natalia Pessoa Noyma
- Laboratory of Ecology and Physiology of Phytoplankton, Department of Plant Biology, University of Rio de Janeiro State, Rua São Francisco Xavier 524-PHLC Sala 511a, 20550-900, Rio de Janeiro, Brazil
| | - Leonardo de Magalhães
- Laboratory of Ecology and Physiology of Phytoplankton, Department of Plant Biology, University of Rio de Janeiro State, Rua São Francisco Xavier 524-PHLC Sala 511a, 20550-900, Rio de Janeiro, Brazil
| | - Marcela Miranda
- Laboratory of Ecology and Physiology of Phytoplankton, Department of Plant Biology, University of Rio de Janeiro State, Rua São Francisco Xavier 524-PHLC Sala 511a, 20550-900, Rio de Janeiro, Brazil
| | - Frank van Oosterhout
- Aquatic Ecology & Water Quality Management Group, Department of Environmental Sciences, Wageningen University, P.O. Box 47, 6700 AA, Wageningen, The Netherlands
| | - Iamê Alves Guedes
- Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, 21949-902, Rio de Janeiro, Brazil
| | - Vera L M Huszar
- Museu Nacional, Federal University of Rio de Janeiro, 20940-040, Rio de Janeiro, Brazil
| | - Marcelo Manzi Marinho
- Laboratory of Ecology and Physiology of Phytoplankton, Department of Plant Biology, University of Rio de Janeiro State, Rua São Francisco Xavier 524-PHLC Sala 511a, 20550-900, Rio de Janeiro, Brazil
| | - Miquel Lürling
- Aquatic Ecology & Water Quality Management Group, Department of Environmental Sciences, Wageningen University, P.O. Box 47, 6700 AA, Wageningen, The Netherlands; Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, 6700 AB, Wageningen, The Netherlands
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21
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Lecina M, Sanchez B, Solà C, Prat J, Roldán M, Hernández M, Bragós R, Paredes CJ, Cairó JJ. Structural changes of Arthrospira sp. after low energy sonication treatment for microalgae harvesting: Elucidating key parameters to detect the rupture of gas vesicles. BIORESOURCE TECHNOLOGY 2017; 223:98-104. [PMID: 27788433 DOI: 10.1016/j.biortech.2016.10.030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 10/07/2016] [Accepted: 10/08/2016] [Indexed: 06/06/2023]
Abstract
The buoyancy suppression by low energy sonication (LES) treatment (0.8W·mL-1, 20kHz, 10s) has recently been proposed as an initial harvesting step for Arthrospira sp. This paper aims to describe the structural changes in Arthrospira sp. after LES treatment and to present how these structural changes affect the results obtained by different analytical techniques. Transmission electron microscopy (TEM) micrographs of trichomes evidenced the gas vesicles rupture but also revealed a rearrangement of thylakoids and more visible phycobilisomes were observed. Differences between treated and untreated samples were detected by confocal microscopy, flow cytometry and optical microscopy but not by electrical impedance spectroscopy (EIS). After LES treatment, 2-fold increase in autofluorescence at 610/660nm was measured (phycocyanin/allophycocyanin emission wavelengths) and a ten-fold decrease in side scatter light intensity (due to a reduction of trichome's inner complexity). This was further confirmed by optical microscopy showing changes on trichomes appearance (from wrinkled to smooth).
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Affiliation(s)
- Martí Lecina
- Department of Chemial, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
| | - Benjamin Sanchez
- Electronic and Biomedical Instrumentation Group, Department of Electronic Engineering, Universitat Politècnica de Catalunya (UPC), Campus Nord, C-4, C/ Jordi Girona 1-3, 08034 Barcelona, Spain
| | - Carles Solà
- Department of Chemial, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Jordi Prat
- Department of Chemial, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Mònica Roldán
- Servei de Microscòpia, Universitat Autònoma de Barcelona, Edifici C, Facultat de Ciències, 08193 Bellaterra, Spain
| | - Mariona Hernández
- Dep. Productes Naturals, Biologia Vegetal i Edafologia, Facultat de Farmàcia, Universitat de Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain
| | - Ramon Bragós
- Electronic and Biomedical Instrumentation Group, Department of Electronic Engineering, Universitat Politècnica de Catalunya (UPC), Campus Nord, C-4, C/ Jordi Girona 1-3, 08034 Barcelona, Spain
| | - Carlos J Paredes
- Department of Chemial, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Jordi J Cairó
- Department of Chemial, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
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22
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McKenzie K, Maclean M, Grant MH, Ramakrishnan P, MacGregor SJ, Anderson JG. The effects of 405 nm light on bacterial membrane integrity determined by salt and bile tolerance assays, leakage of UV-absorbing material and SYTOX green labelling. MICROBIOLOGY (READING, ENGLAND) 2016; 162:1680-1688. [PMID: 27499074 PMCID: PMC5068139 DOI: 10.1099/mic.0.000350] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 08/05/2016] [Indexed: 12/22/2022]
Abstract
Bacterial inactivation by 405 nm light is accredited to the photoexcitation of intracellular porphyrin molecules resulting in energy transfer and the generation of reactive oxygen species that impart cellular oxidative damage. The specific mechanism of cellular damage, however, is not fully understood. Previous work has suggested that destruction of nucleic acids may be responsible for inactivation; however, microscopic imaging has suggested membrane damage as a major constituent of cellular inactivation. This study investigates the membrane integrity of Escherichia coli and Staphylococcus aureus exposed to 405 nm light. Results indicated membrane damage to both species, with loss of salt and bile tolerance by S. aureus and E. coli, respectively, consistent with reduced membrane integrity. Increased nucleic acid release was also demonstrated in 405 nm light-exposed cells, with up to 50 % increase in DNA concentration into the extracellular media in the case of both organisms. SYTOX green fluorometric analysis, however, demonstrated contradictory results between the two test species. With E. coli, increasing permeation of SYTOX green was observed following increased exposure, with >500 % increase in fluorescence, whereas no increase was observed with S. aureus. Overall, this study has provided good evidence that 405 nm light exposure causes loss of bacterial membrane integrity in E. coli, but the results with S. aureus are more difficult to explain. Further work is required to gain greater understanding of the inactivation mechanism in different bacterial species, as there are likely to be other targets within the cell that are also impaired by the oxidative damage from photo-generated reactive oxygen species.
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Affiliation(s)
- Karen McKenzie
- Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), University of Strathclyde, 204 George Street, Glasgow, Scotland G1 1XW, UK
| | - Michelle Maclean
- Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), University of Strathclyde, 204 George Street, Glasgow, Scotland G1 1XW, UK
- Department of Biomedical Engineering, University of Strathclyde, Wolfson Centre, 106 Rottenrow, Glasgow, Scotland G4 0NW, UK
| | - M. Helen Grant
- Department of Biomedical Engineering, University of Strathclyde, Wolfson Centre, 106 Rottenrow, Glasgow, Scotland G4 0NW, UK
| | - Praveen Ramakrishnan
- Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), University of Strathclyde, 204 George Street, Glasgow, Scotland G1 1XW, UK
- Department of Biomedical Engineering, University of Strathclyde, Wolfson Centre, 106 Rottenrow, Glasgow, Scotland G4 0NW, UK
| | - Scott J. MacGregor
- Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), University of Strathclyde, 204 George Street, Glasgow, Scotland G1 1XW, UK
| | - John G. Anderson
- Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), University of Strathclyde, 204 George Street, Glasgow, Scotland G1 1XW, UK
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23
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Tashyreva D, Elster J. Annual Cycles of Two Cyanobacterial Mat Communities in Hydro-Terrestrial Habitats of the High Arctic. MICROBIAL ECOLOGY 2016; 71:887-900. [PMID: 26841797 DOI: 10.1007/s00248-016-0732-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 01/18/2016] [Indexed: 06/05/2023]
Abstract
Cyanobacteria form extensive macroscopic mats in shallow freshwater environments in the High Arctic and Antarctic. In these habitats, the communities are exposed to seasonal freezing and desiccation as well as to freeze-thawing and drying-rewetting cycles. Here, we characterized the annual cycles of two Phormidium communities in very shallow seepages located in central Svalbard. We observed the structure of the communities and the morphology, ultrastructure, metabolic activity, and viability of filaments and single cells. The communities overwintered as frozen mats, which were formed by long filaments enclosed in thick multilayered polysaccharide sheaths. No morphologically and/or ultrastructurally distinct spore-like cells were produced for surviving the winter, and the winter survival of the communities was not provided by a few resistant cells, which did not undergo visible morphological and ultrastructural transformations. Instead, a high proportion of cells in samples (85%) remained viable after prolonged freezing. The sheaths were the only morphological adaption, which seemed to protect the trichomes from damage due to freezing and freeze-associated dehydration. The cells in the overwintering communities were not dormant, as all viable cells rapidly resumed respiration after thawing, and their nucleoids were not condensed. During the whole vegetative season, defined by the presence of water in a liquid state, the communities were constantly metabolically active and contained <1% of dead and injured cells. The morphology and ultrastructure of the cells remained unaltered during observations throughout the year, except for light-induced changes in thylakoids. The dissemination events are likely to occur in spring as most of the trichomes were split into short fragments (hormogonia), a substantial proportion of which were released into the environment by gliding out of their sheaths, as well as by cracking and dissolving their sheaths. The short fragments subsequently grew longer and gradually produced new polysaccharide sheaths.
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Affiliation(s)
- Daria Tashyreva
- Centre for Polar Ecology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic.
- Botany Department, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic.
| | - Josef Elster
- Centre for Polar Ecology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
- Institute of Botany, Academy of Sciences of the Czech Republic, Třeboň, Czech Republic
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Vítek P, Ascaso C, Artieda O, Wierzchos J. Raman imaging in geomicrobiology: endolithic phototrophic microorganisms in gypsum from the extreme sun irradiation area in the Atacama Desert. Anal Bioanal Chem 2016; 408:4083-92. [DOI: 10.1007/s00216-016-9497-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 03/16/2016] [Indexed: 12/31/2022]
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Tashyreva D, Elster J. Effect of nitrogen starvation on desiccation tolerance of Arctic Microcoleus strains (cyanobacteria). Front Microbiol 2015; 6:278. [PMID: 25904909 PMCID: PMC4389727 DOI: 10.3389/fmicb.2015.00278] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 03/19/2015] [Indexed: 11/20/2022] Open
Abstract
Although desiccation tolerance of Microcoleus species is a well-known phenomenon, there is very little information about their limits of desiccation tolerance in terms of cellular water content, the survival rate of their cells, and the environmental factors inducing their resistance to drying. We have discovered that three Microcoleus strains, isolated from terrestrial habitats of the High Arctic, survived extensive dehydration (to 0.23 g water g-1 dry mass), but did not tolerate complete desiccation (to 0.03 g water g-1 dry mass) regardless of pre-desiccation treatments. However, these treatments were critical for the survival of incomplete desiccation: cultures grown under optimal conditions failed to survive even incomplete desiccation; a low temperature enabled only 0–15% of cells to survive, while 39.8–65.9% of cells remained alive and intact after nitrogen starvation. Unlike Nostoc, which co-exists with Microcoleus in Arctic terrestrial habitats, Microcoleus strains are not truly anhydrobiotic and do not possess constitutive desiccation tolerance. Instead, it seems that the survival strategy of Microcoleus in periodically dry habitats involves avoidance of complete desiccation, but tolerance to milder desiccation stress, which is induced by suboptimal conditions (e.g., nitrogen starvation).
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Affiliation(s)
- Daria Tashyreva
- Centre for Polar Ecology, Faculty of Science, University of South Bohemia České Budějovice, Czech Republic ; Department of Botany, Faculty of Science, University of South Bohemia České Budějovice, Czech Republic
| | - Josef Elster
- Centre for Polar Ecology, Faculty of Science, University of South Bohemia České Budějovice, Czech Republic ; Institute of Botany, Academy of Sciences of the Czech Republic Třeboň , Czech Republic
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Wang Y, Zhou Q, Wang Y, Ren J, Zhao H, Wu S, Yang J, Zhen J, Luo Y, Wang X, Gu Y. In vitro photodynamic inactivation effects of Ru(II) complexes on clinical methicillin-resistant Staphylococcus aureus planktonic and biofilm cultures. Photochem Photobiol 2014; 91:124-33. [PMID: 25354324 DOI: 10.1111/php.12378] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Accepted: 10/20/2014] [Indexed: 01/03/2023]
Abstract
Photosensitizers (PSs) combined with light are able to generate antimicrobial effects. Ru(II) complexes have been recognized as a novel class of PSs. In this study, we investigated the effectiveness of photodynamic inactivation (PDI) mediated by three Ru(II) polypyridine complexes, 1-3, against four isolates of clinical methicillin-resistant Staphylococcus aureus (MRSA-1, MRSA-2, MRSA-3 and MRSA-4). In PDI of a planktonic culture of MRSA-1, compound 3 showed the highest efficacy, likely owing to its advantageous light absorption, (1) O2 quantum yield and bacterial cellular binding. The PDI efficacy of 3 was further evaluated against all other strains and MRSA-1 biofilms. At appropriate PS concentrations, viability reduction of 100% or 96.83% was observed in planktonic or biofilm forms of MRSA, respectively. The mechanisms of action were investigated using negative staining transmission electron microscopy (TEM), confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). It was demonstrated that PDI of planktonic bacteria was achieved primarily through damage to the cell envelope. Biofilms were eliminated through both the destruction of their structure and inactivation of the individual bacterial cells. In conclusion, Ru(II) complexes, especially 3, are potential candidates for the effective photodynamic control of MRSA infections.
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Affiliation(s)
- Yucheng Wang
- Department of Laser Medicine, Chinese PLA General Hospital, Beijing, China; College of Medicine, Nankai University, Tianjin, China
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Fluorescent fingerprints of endolithic phototrophic cyanobacteria living within halite rocks in the Atacama Desert. Appl Environ Microbiol 2014; 80:2998-3006. [PMID: 24610843 DOI: 10.1128/aem.03428-13] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Halite deposits from the hyperarid zone of the Atacama Desert reveal the presence of endolithic microbial colonization dominated by cyanobacteria associated with heterotrophic bacteria and archaea. Using the λ-scan confocal laser scanning microscopy (CLSM) option, this study examines the autofluorescence emission spectra produced by single cyanobacterial cells found inside halite rocks and by their photosynthetic pigments. Photosynthetic pigments could be identified according to the shapes of the emission spectra and wavelengths of fluorescence peaks. According to their fluorescence fingerprints, three groups of cyanobacterial cells were identified within this natural extreme microhabitat: (i) cells producing a single fluorescence peak corresponding to the emission range of phycobiliproteins and chlorophyll a, (ii) cells producing two fluorescence peaks within the red and green signal ranges, and (iii) cells emitting only low-intensity fluorescence within the nonspecific green fluorescence signal range. Photosynthetic pigment fingerprints emerged as indicators of the preservation state or viability of the cells. These observations were supported by a cell plasma membrane integrity test based on Sytox Green DNA staining and by transmission electron microscopy ultrastructural observations of cyanobacterial cells.
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Pichrtová M, Hájek T, Elster J. Osmotic stress and recovery in field populations of Zygnema sp. (Zygnematophyceae, Streptophyta) on Svalbard (High Arctic) subjected to natural desiccation. FEMS Microbiol Ecol 2014; 89:270-80. [PMID: 24476153 DOI: 10.1111/1574-6941.12288] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 01/06/2014] [Accepted: 01/16/2014] [Indexed: 12/01/2022] Open
Abstract
Zygnema is a genus of filamentous green algae belonging to the class of Zygnematophyceae (Streptophyta). In the Arctic, it typically forms extensive mats in habitats that regularly dry out during summer, and therefore, mechanisms of stress resistance are expected. We investigated its natural populations with respect to production of specialized desiccation-resistant cells and osmotic acclimation. Six populations in various stages of natural desiccation were selected, from wet biomass floating in water to dried paper-like crusts. After rewetting, plasmolysis and osmotic stress effects were studied using hypertonic sorbitol solutions, and the physiological state was estimated using chlorophyll a fluorescence parameters. All populations of Zygnema sp. formed stationary-phase cells filled with storage products. In green algal research, such cells are traditionally called akinetes. However, the populations differed in their reaction to osmotic stress. Whereas the wet-collected samples were strongly impaired, the osmotic stress resistance of the naturally dried samples was comparable to that of true aeroterrestrial algae. We showed that arctic populations of Zygnema acclimate well to natural desiccation via hardening that is mediated by slow desiccation. As no other types of specialized cells were observed, we assume that the naturally hardened akinetes also play a key role in winter survival.
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Affiliation(s)
- Martina Pichrtová
- Institute of Botany, Academy of Sciences of the Czech Republic, Třeboň, Czech Republic; Department of Botany, Faculty of Science, Charles University in Prague, Prague, Czech Republic
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Peng Y, Lee-Pullen TF, Heel K, Millar AH, Baer B. Quantifying spore viability of the honey bee pathogenNosema apisusing flow cytometry. Cytometry A 2013; 85:454-62. [DOI: 10.1002/cyto.a.22428] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 10/30/2013] [Accepted: 11/26/2013] [Indexed: 12/11/2022]
Affiliation(s)
- Yan Peng
- Centre for Integrative Bee Research (CIBER); The University of Western Australia; Crawley Western Australia 6009 Australia
- ARC Centre of Excellence in Plant Energy and Centre for Comparative Analysis of Biomolecular Networks (CABIN); The University of Western Australia; Crawley Western Australia 6009 Australia
| | - Tracey F. Lee-Pullen
- Centre for Microscopy, Characterisation and Analysis; The University of Western Australia; Crawley Western Australia 6009 Australia
| | - Kathy Heel
- Centre for Microscopy, Characterisation and Analysis; The University of Western Australia; Crawley Western Australia 6009 Australia
| | - A. Harvey Millar
- Centre for Integrative Bee Research (CIBER); The University of Western Australia; Crawley Western Australia 6009 Australia
- ARC Centre of Excellence in Plant Energy and Centre for Comparative Analysis of Biomolecular Networks (CABIN); The University of Western Australia; Crawley Western Australia 6009 Australia
| | - Boris Baer
- Centre for Integrative Bee Research (CIBER); The University of Western Australia; Crawley Western Australia 6009 Australia
- ARC Centre of Excellence in Plant Energy and Centre for Comparative Analysis of Biomolecular Networks (CABIN); The University of Western Australia; Crawley Western Australia 6009 Australia
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