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Roncero-Ramos B, Savaglia V, Durieu B, Van de Vreken I, Richel A, Wilmotte A. Ecophysiological and genomic approaches to cyanobacterial hardening for restoration. JOURNAL OF PHYCOLOGY 2024; 60:465-482. [PMID: 38373045 DOI: 10.1111/jpy.13436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 12/15/2023] [Accepted: 12/15/2023] [Indexed: 02/20/2024]
Abstract
Cyanobacteria inhabit extreme environments, including drylands, providing multiple benefits to the ecosystem. Soil degradation in warm drylands is increasing due to land use intensification. Restoration methods adapted to the extreme stress in drylands are being developed, such as cyanobacteria inoculation to recover biocrusts. For this type of restoration method to be a success, it is crucial to optimize the survival of inoculated cyanobacteria in the field. One strategy is to harden them to be acclimated to stressful conditions after laboratory culturing. Here, we analyzed the genome and ecophysiological response to osmotic desiccation and UVR stresses of an Antarctic cyanobacterium, Stenomitos frigidus ULC029, which is closely related to other cyanobacteria from warm and cold dryland soils. Chlorophyll a concentrations showed that preculturing ULC029 under moderate osmotic stress improved its survival during an assay of desiccation plus rehydration under UVR. Additionally, its sequential exposure to these stress factors increased the production of exopolysaccharides, carotenoids, and scytonemin. Desiccation, but not osmotic stress, increased the concentrations of the osmoprotectants trehalose and sucrose. However, osmotic stress might induce the production of other osmoprotectants, for which the complete pathways were observed in the ULC029 genome. In total, 140 genes known to be involved in stress resistance were annotated. Here, we confirm that the sequential application of moderate osmotic stress and dehydration could improve cyanobacterial hardening for soil restoration by inducing several resistance mechanisms. We provide a high-quality genome of ULC029 and a description of the main resistance mechanisms (i.e., production of exopolysaccharides, osmoprotectants, chlorophyll, and carotenoids; DNA repair; and oxidative stress protection).
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Affiliation(s)
- Beatriz Roncero-Ramos
- InBios-Molecular Diversity and Ecology of Cyanobacteria, University of Liège, Liege, Belgium
- Departamento de Biología Vegetal y Ecología, Universidad de Sevilla, Sevilla, Spain
| | - Valentina Savaglia
- InBios-Molecular Diversity and Ecology of Cyanobacteria, University of Liège, Liege, Belgium
- Laboratory of Protistology & Aquatic Ecology, Ghent University, Ghent, Belgium
| | - Benoit Durieu
- InBios-Molecular Diversity and Ecology of Cyanobacteria, University of Liège, Liege, Belgium
| | | | - Aurore Richel
- TERRA-Biomass and Green Technologies, University of Liège, Gembloux, Belgium
| | - Annick Wilmotte
- InBios-Molecular Diversity and Ecology of Cyanobacteria, University of Liège, Liege, Belgium
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Debnath S, Muthuraj M, Bandyopadhyay TK, Bobby MN, Vanitha K, Tiwari ON, Bhunia B. Engineering strategies and applications of cyanobacterial exopolysaccharides: A review on past achievements and recent perspectives. Carbohydr Polym 2024; 328:121686. [PMID: 38220318 DOI: 10.1016/j.carbpol.2023.121686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 11/08/2023] [Accepted: 12/08/2023] [Indexed: 01/16/2024]
Abstract
Cyanobacteria are ideally suited for developing sustainable biological products but are underdeveloped due to a lack of genetic tools. Exopolysaccharide (EPS) is one of the essential bioproducts with widespread industrial applications. Despite their unique structural characteristics associated with distinct biological and physicochemical aspects, EPS from cyanobacteria has been underexplored. However, it is expected to accelerate in the near future due to the utilization of low-cost cyanobacterial platforms and readily available information on the structural data and specific features of these biopolymers. In recent years, cyanobacterial EPSs have attracted growing scientific attention due to their simple renewability, rheological characteristics, massive production, and potential uses in several biotechnology domains. This review focuses on the most recent research on potential new EPS producers and their distinct compositions responsible for novel biological activities. Additionally, nutritional and process parameters discovered recently for enhancing EPS production and engineering strategies applied currently to control the biosynthetic pathway for enhanced EPS production are critically highlighted. The process intensification of previously developed EPS extraction and purification processes from cyanobacterial biomass is also extensively explained. Furthermore, the newly reported biotechnological applications of cyanobacterial exopolysaccharides are also discussed.
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Affiliation(s)
- Shubhankar Debnath
- Bioproducts Processing Research Laboratory (BPRL), Department of Bio Engineering, National Institute of Technology, Agartala 799046, India
| | - Muthusivaramapandian Muthuraj
- Bioproducts Processing Research Laboratory (BPRL), Department of Bio Engineering, National Institute of Technology, Agartala 799046, India.
| | | | - Md Nazneen Bobby
- Department of Biotechnology, Vignan's Foundation for Science Technology and Research, Guntur 522213, Andhra Pradesh, India
| | - Kondi Vanitha
- Department of Pharmaceutics, Vishnu Institute of Pharmaceutical Education and Research, Narsapur, Medak, Telangana, India
| | - Onkar Nath Tiwari
- Centre for Conservation and Utilization of Blue Green Algae, Division of Microbiology, Indian Agricultural Research Institute (ICAR), New Delhi 110012, India.
| | - Biswanath Bhunia
- Bioproducts Processing Research Laboratory (BPRL), Department of Bio Engineering, National Institute of Technology, Agartala 799046, India.
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3
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Li S, Duan G, Xi Y, Chu Y, Li F, Ho SH. Insights into the role of extracellular polymeric substances (EPS) in the spread of antibiotic resistance genes. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 343:123285. [PMID: 38169168 DOI: 10.1016/j.envpol.2023.123285] [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: 08/21/2023] [Revised: 11/28/2023] [Accepted: 12/30/2023] [Indexed: 01/05/2024]
Abstract
Antibiotic resistance genes (ARG) are prevalent in aquatic environments. Discharge from wastewater treatment plants is an important point source of ARG release into the environment. It has been reported that biological treatment processes may enhance rather than remove ARG because of their presence in sludge. Attenuation of ARG in biotechnological processes has been studied in depth, showing that many microorganisms can secrete complex extracellular polymeric substances (EPS). These EPS can serve as multifunctional elements of microbial communities, involving aspects, such as protection, structure, recognition, adhesion, and physiology. These aspects can influence the interaction between microbial cells and extracellular ARG, as well as the uptake of extracellular ARG by microbial cells, thus changing the transformative capability of extracellular ARG. However, it remains unclear whether EPS can affect horizontal ARG transfer, which is one of the main processes of ARG dissemination. In light of this knowledge gap, this review provides insight into the role of EPS in the transmission of ARGs; furthermore, the mechanism of ARG spread is analyzed, and the molecular compositions and functional properties of EPS are summarized; also, how EPS influence ARG mitigation is addressed, and factors impacting how EPS facilitate ARG during wastewater treatment are summarized. This review provides comprehensive insights into the role of EPS in controlling the transport and fate of ARG during biodegradation processes at the mechanistic level.
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Affiliation(s)
- Shengnan Li
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang Province, 150090, China
| | - Guoxiang Duan
- Heilongjiang Academy of Chinese Medical Sciences, Harbin, China
| | - Yucan Xi
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang Province, 150090, China
| | - Yuhao Chu
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang Province, 150090, China
| | - Fengxiang Li
- Key Laboratory of Pollution Processes and Environmental Criteria at Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, China
| | - Shih-Hsin Ho
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang Province, 150090, China.
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Jeewon R, Aullybux AA, Puchooa D, Nazurally N, Alrefaei AF, Zhang Y. Marine Microbial Polysaccharides: An Untapped Resource for Biotechnological Applications. Mar Drugs 2023; 21:420. [PMID: 37504951 PMCID: PMC10381399 DOI: 10.3390/md21070420] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 07/18/2023] [Accepted: 07/19/2023] [Indexed: 07/29/2023] Open
Abstract
As the largest habitat on Earth, the marine environment harbors various microorganisms of biotechnological potential. Indeed, microbial compounds, especially polysaccharides from marine species, have been attracting much attention for their applications within the medical, pharmaceutical, food, and other industries, with such interest largely stemming from the extensive structural and functional diversity displayed by these natural polymers. At the same time, the extreme conditions within the aquatic ecosystem (e.g., temperature, pH, salinity) may not only induce microorganisms to develop a unique metabolism but may also increase the likelihood of isolating novel polysaccharides with previously unreported characteristics. However, despite their potential, only a few microbial polysaccharides have actually reached the market, with even fewer being of marine origin. Through a synthesis of relevant literature, this review seeks to provide an overview of marine microbial polysaccharides, including their unique characteristics. In particular, their suitability for specific biotechnological applications and recent progress made will be highlighted before discussing the challenges that currently limit their study as well as their potential for wider applications. It is expected that this review will help to guide future research in the field of microbial polysaccharides, especially those of marine origin.
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Affiliation(s)
- Rajesh Jeewon
- Department of Health Sciences, Faculty of Medicine and Health Sciences, University of Mauritius, Réduit 80837, Mauritius
- Department of Zoology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Aadil Ahmad Aullybux
- Department of Agricultural and Food Science, Faculty of Agriculture, University of Mauritius, Réduit 80837, Mauritius
| | - Daneshwar Puchooa
- Department of Agricultural and Food Science, Faculty of Agriculture, University of Mauritius, Réduit 80837, Mauritius
| | - Nadeem Nazurally
- Department of Agricultural and Food Science, Faculty of Agriculture, University of Mauritius, Réduit 80837, Mauritius
| | - Abdulwahed Fahad Alrefaei
- Department of Zoology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Ying Zhang
- School of Ecology and Natural Conservation, Beijing Forestry University, 35 East Qinghua Road, Haidian District, Beijing 100083, China
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Netrusov AI, Liyaskina EV, Kurgaeva IV, Liyaskina AU, Yang G, Revin VV. Exopolysaccharides Producing Bacteria: A Review. Microorganisms 2023; 11:1541. [PMID: 37375041 DOI: 10.3390/microorganisms11061541] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 05/31/2023] [Accepted: 06/05/2023] [Indexed: 06/29/2023] Open
Abstract
Bacterial exopolysaccharides (EPS) are essential natural biopolymers used in different areas including biomedicine, food, cosmetic, petroleum, and pharmaceuticals and also in environmental remediation. The interest in them is primarily due to their unique structure and properties such as biocompatibility, biodegradability, higher purity, hydrophilic nature, anti-inflammatory, antioxidant, anti-cancer, antibacterial, and immune-modulating and prebiotic activities. The present review summarizes the current research progress on bacterial EPSs including their properties, biological functions, and promising applications in the various fields of science, industry, medicine, and technology, as well as characteristics and the isolation sources of EPSs-producing bacterial strains. This review provides an overview of the latest advances in the study of such important industrial exopolysaccharides as xanthan, bacterial cellulose, and levan. Finally, current study limitations and future directions are discussed.
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Affiliation(s)
- Alexander I Netrusov
- Department of Microbiology, Faculty of Biology, M.V. Lomonosov Moscow State University, 119234 Moscow, Russia
- Faculty of Biology and Biotechnology, High School of Economics, 119991 Moscow, Russia
| | - Elena V Liyaskina
- Department of Biotechnology, Biochemistry and Bioengineering, National Research Ogarev Mordovia State University, 430005 Saransk, Russia
| | - Irina V Kurgaeva
- Department of Biotechnology, Biochemistry and Bioengineering, National Research Ogarev Mordovia State University, 430005 Saransk, Russia
| | - Alexandra U Liyaskina
- Institute of the World Ocean, Far Eastern Federal University, 690922 Vladivostok, Russia
| | - Guang Yang
- Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Viktor V Revin
- Department of Biotechnology, Biochemistry and Bioengineering, National Research Ogarev Mordovia State University, 430005 Saransk, Russia
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Assessing the Antitumor Potential of Variants of the Extracellular Carbohydrate Polymer from Synechocystis Δsigf Mutant. Polymers (Basel) 2023; 15:polym15061382. [PMID: 36987163 PMCID: PMC10057057 DOI: 10.3390/polym15061382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 03/06/2023] [Accepted: 03/07/2023] [Indexed: 03/12/2023] Open
Abstract
Cancer is a leading cause of death worldwide with a huge societal and economic impact. Clinically effective and less expensive anticancer agents derived from natural sources can help to overcome limitations and negative side effects of chemotherapy and radiotherapy. Previously, we showed that the extracellular carbohydrate polymer of a Synechocystis ΔsigF overproducing mutant displayed a strong antitumor activity towards several human tumor cell lines, by inducing high levels of apoptosis through p53 and caspase-3 activation. Here, the ΔsigF polymer was manipulated to obtain variants that were tested in a human melanoma (Mewo) cell line. Our results demonstrated that high molecular mass fractions were important for the polymer bioactivity, and that the reduction of the peptide content generated a variant with enhanced in vitro antitumor activity. This variant, and the original ΔsigF polymer, were further tested in vivo using the chick chorioallantoic membrane (CAM) assay. Both polymers significantly decreased xenografted CAM tumor growth and affected tumor morphology, by promoting less compact tumors, validating their antitumor potential in vivo. This work contributes with strategies for the design and testing tailored cyanobacterial extracellular polymers and further strengths the relevance of evaluating this type of polymers for biotechnological/biomedical applications.
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Untargeted GC-MS reveals differential regulation of metabolic pathways in cyanobacterium Anabaena and its biofilms with Trichoderma viride and Providencia sp. CURRENT RESEARCH IN MICROBIAL SCIENCES 2022; 3:100174. [DOI: 10.1016/j.crmicr.2022.100174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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8
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Vandana, Das S. Genetic regulation, biosynthesis and applications of extracellular polysaccharides of the biofilm matrix of bacteria. Carbohydr Polym 2022; 291:119536. [DOI: 10.1016/j.carbpol.2022.119536] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 04/22/2022] [Accepted: 04/22/2022] [Indexed: 11/02/2022]
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9
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Dindhoria K, Kumar S, Baliyan N, Raphel S, Halami PM, Kumar R. Bacillus licheniformis MCC 2514 genome sequencing and functional annotation for providing genetic evidence for probiotic gut adhesion properties and its applicability as a bio-preservative agent. Gene 2022; 840:146744. [PMID: 35863717 DOI: 10.1016/j.gene.2022.146744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 06/04/2022] [Accepted: 07/14/2022] [Indexed: 11/04/2022]
Abstract
Bacillus licheniformis is a well-known probiotic that can be found in a variety of foods. The strain Bacillus licheniformis MCC 2514 was previously characterized by our group for its bio-physiological capabilities establishing it as a promising probiotic, but information on the genetic evidence for its attributes was lacking. In the current study, whole genome analysis identified the underlying molecular determinants responsible for its probiotic potential. The circular genome of MCC 2514 was 4,230,480 bp with 46.2% GC content, 24 rRNA, and 83 tRNA genes. The pangenome analysis between B. licheniformis MCC 2514 and 12 other B. licheniformis strains revealed a pangenome of 6008 genes and core genome of 3775 genes. Genome mining revealed NRPS and bacteriocins producing gene clusters indicating its biocontrol properties. Several genes encoding carbohydrate degrading enzymes, which aid in proper food degradation in the intestine, were also observed. Stress tolerance, vitamin, and essential amino acids biosynthesis related genes were found, which are important characteristics of a probiotic strain. Additionally, vital genes responsible for gut adhesion and biofilm formation were observed in its genome. The bacterium has been shown to improve the shelf life of idli batter by preventing whey separation, CO2, and odour production while maintaining the pH of 3.96-4.29, especially at cold temperatures. It has significantly reduced coliform contamination at both room and low temperatures, demonstrating its bio-preservative ability, which is also corroborated by the presence of the NRPS and bacteriocin gene clusters in its genome. The present study helped to understand both, the ability of B. licheniformis MCC 2514 to adapt the intestinal gut environment and its probiotic functionality for food preservation.
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Affiliation(s)
- Kiran Dindhoria
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh 176061, India; Academy of Scientific and Innovative Research (AcSIR), CSIR- Human Resource Development Centre, Ghaziabad, Uttar Pradesh 201 002, India
| | - Sanjeet Kumar
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh 176061, India
| | - Neha Baliyan
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh 176061, India; Academy of Scientific and Innovative Research (AcSIR), CSIR- Human Resource Development Centre, Ghaziabad, Uttar Pradesh 201 002, India
| | - Steji Raphel
- Department of Microbiology & Fermentation Technology, CSIR- Central Food Technological Research Institute, Mysore 570 020, India; Academy of Scientific and Innovative Research (AcSIR), CSIR- Human Resource Development Centre, Ghaziabad, Uttar Pradesh 201 002, India
| | - Prakash M Halami
- Department of Microbiology & Fermentation Technology, CSIR- Central Food Technological Research Institute, Mysore 570 020, India; Academy of Scientific and Innovative Research (AcSIR), CSIR- Human Resource Development Centre, Ghaziabad, Uttar Pradesh 201 002, India.
| | - Rakshak Kumar
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh 176061, India; Academy of Scientific and Innovative Research (AcSIR), CSIR- Human Resource Development Centre, Ghaziabad, Uttar Pradesh 201 002, India.
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Extracellular Polymeric Substances Produced by the Thermophilic Cyanobacterium Gloeocapsa gelatinosa: Characterization and Assessment of Their Antioxidant and Metal-Chelating Activities. Mar Drugs 2022; 20:md20040227. [PMID: 35447900 PMCID: PMC9029086 DOI: 10.3390/md20040227] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 03/16/2022] [Accepted: 03/24/2022] [Indexed: 11/26/2022] Open
Abstract
Cyanobacteria, particularly thermophilic strains, represent an important potential source of EPSs, harboring structural complexity that predicts diverse and specific bioactive potential. The thermophilic cyanobacteria Gloeocapsa gelatinosa, isolated from a natural hot source in Ain Echfa (Tunisia), was cultivated in a cylindrical reactor, and the production of biomass and EPSs was investigated. Results revealed that the strain is amongst the most efficient EPSs producers (0.89 g L−1) and that EPSs production was not correlated with the growth phase. EPSs were sulfated heteropolysaccharides containing carbohydrates (70%) based on nine different monosaccharides, mainly mannose (22%), and with the presence of two uronic acids. EPSs were formed by two polymers moieties with a molecular weight of 598.3 ± 7.2 and 67.2 ± 4.4 kDa. They are thermostable in temperatures exceeding 100 °C and have an anionic nature (zeta potential of −40 ± 2 mV). Atomic force microscopy showed that EPSs formed multimodal lumps with 88 nm maximum height. EPSs presented high water holding capacity (70.29 ± 2.36%) and solubility index (97.43 ± 1.24%), and a strong bivalent metal sorption capacity especially for Cu2+ (91.20 ± 1.25%) and Fe2+ (75.51 ± 0.71%). The antioxidant activity of G. gelatinosa EPSs was investigated using four methods: the β-carotene-bleaching activity, DPPH assays, iron-reducing activity, and metal-chelating activity. EPS has shown high potential as free radicals’ scavenger, with an IC50 on DPPH (0.2 g L−1) three-fold lower than ascorbic acid (0.6 g L −1) and as a metal chelating activity (IC50 = 0.4 g L−1) significantly lower than EDTA. The obtained results allow further exploration of the thermophilic G. gelatinosa for several biotechnological and industrial applications.
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Yan N, Hu Y, Tang BZ, Wang WX. Real-Time 3D Framework Tracing of Extracellular Polymeric Substances by an AIE-Active Nanoprobe. ACS Sens 2021; 6:4206-4216. [PMID: 34739214 DOI: 10.1021/acssensors.1c01821] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Extracellular polymeric substances (EPS) are produced by many microorganisms and play an essential role in physiological systems such as nutrient storage and stress resistance. Besides, EPS show great potential in biomedical and therapeutic applications due to their biocompatibility and biodegradability. In situ noninvasive monitoring of the EPS produced by microorganisms is thus critical but has not yet been achieved. Herein, we developed a novel aggregation-induced emission (AIE) active nanoprobe enabling in situ visualization of the EPS distribution produced by various microorganisms (cyanobacteria, yeast, freshwater, and marine phytoplankton). The synthesized AIE-active nanoprobe displayed excellent specificity and precision for the staining of EPS, as well as strong photostability, showing great advantage in sensing the EPS in living organisms. With the application of this novel probe, the three-dimensional (3D) framework of EPS distribution was visualized under different environmental conditions (temperature, light intensity, nutrition, and pH). The EPS distribution was found to correlate significantly with the metal tolerance and cyanobacterial photosynthesis capability. Collectively, this study proposed an AIE-active nanoprobe for visualizing the EPS distribution and quantifying the EPS thickness/volume, and has significant implications in understanding the physiological functions of microorganisms.
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Affiliation(s)
- Neng Yan
- School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong 999077, China
| | - Yubing Hu
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, HKUST, Clear Water Bay, Kowloon, Hong Kong 999077, China
- Department of Chemical Engineering, Imperial College London, London SW7 2BU, U.K
| | - Ben Zhong Tang
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, HKUST, Clear Water Bay, Kowloon, Hong Kong 999077, China
- Shenzhen Institute of Molecular Aggregate Science and Engineering, School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, 2001 Longxiang Boulevard, Longgang District, Shenzhen, Guangdong 518172, China
| | - Wen-Xiong Wang
- School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong 999077, China
- Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China
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Santos M, Pacheco CC, Yao L, Hudson EP, Tamagnini P. CRISPRi as a Tool to Repress Multiple Copies of Extracellular Polymeric Substances (EPS)-Related Genes in the Cyanobacterium Synechocystis sp. PCC 6803. Life (Basel) 2021; 11:life11111198. [PMID: 34833074 PMCID: PMC8620461 DOI: 10.3390/life11111198] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 10/28/2021] [Accepted: 11/03/2021] [Indexed: 12/03/2022] Open
Abstract
The use of the versatile cyanobacterial extracellular polymeric substances (EPS) for biotechnological/biomedical applications implies an extensive knowledge of their biosynthetic pathways to improve/control polymer production yields and characteristics. The multiple copies of EPS-related genes, scattered throughout cyanobacterial genomes, adds another layer of complexity, making these studies challenging and time-consuming. Usually, this issue would be tackled by generating deletion mutants, a process that in cyanobacteria is also hindered by the polyploidy. Thus, the use of the CRISPRi multiplex system constitutes an efficient approach to addressing this redundancy. Here, three putative Synechocystis sp. PCC 6803 kpsM homologues (slr0977, slr2107, and sll0574) were repressed using this methodology. The characterization of the 3-sgRNA mutant in terms of fitness/growth and total carbohydrates, released and capsular polysaccharides, and its comparison with previously generated single knockout mutants pointed towards Slr0977 being the key KpsM player in Synechocystis EPS production. This work validates CRISPRi as a powerful tool to unravel cyanobacterial complex EPS biosynthetic pathways expediting this type of studies.
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Affiliation(s)
- Marina Santos
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4000-008 Porto, Portugal; (M.S.); (C.C.P.)
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4000-008 Porto, Portugal
- Programa Doutoral em Biologia Molecular e Celular (MCbiology), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, 4000-008 Porto, Portugal
| | - Catarina C. Pacheco
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4000-008 Porto, Portugal; (M.S.); (C.C.P.)
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4000-008 Porto, Portugal
| | - Lun Yao
- Science for Life Laboratory, KTH Royal Institute of Technology, 10004 Stockholm, Sweden; (L.Y.); (E.P.H.)
- Department of Protein Science, KTH Royal Institute of Technology, 10004 Stockholm, Sweden
| | - Elton P. Hudson
- Science for Life Laboratory, KTH Royal Institute of Technology, 10004 Stockholm, Sweden; (L.Y.); (E.P.H.)
- Department of Protein Science, KTH Royal Institute of Technology, 10004 Stockholm, Sweden
| | - Paula Tamagnini
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4000-008 Porto, Portugal; (M.S.); (C.C.P.)
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4000-008 Porto, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, 4000-008 Porto, Portugal
- Correspondence: ; Tel.: +351-226074957
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Banerjee A, Sarkar S, Govil T, González-Faune P, Cabrera-Barjas G, Bandopadhyay R, Salem DR, Sani RK. Extremophilic Exopolysaccharides: Biotechnologies and Wastewater Remediation. Front Microbiol 2021; 12:721365. [PMID: 34489911 PMCID: PMC8417407 DOI: 10.3389/fmicb.2021.721365] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 07/26/2021] [Indexed: 01/18/2023] Open
Abstract
Various microorganisms thrive under extreme environments, like hot springs, hydrothermal vents, deep marine ecosystems, hyperacid lakes, acid mine drainage, high UV exposure, and more. To survive against the deleterious effect of these extreme circumstances, they form a network of biofilm where exopolysaccharides (EPSs) comprise a substantial part. The EPSs are often polyanionic due to different functional groups in their structural backbone, including uronic acids, sulfated units, and phosphate groups. Altogether, these chemical groups provide EPSs with a negative charge allowing them to (a) act as ligands toward dissolved cations as well as trace, and toxic metals; (b) be tolerant to the presence of salts, surfactants, and alpha-hydroxyl acids; and (c) interface the solubilization of hydrocarbons. Owing to their unique structural and functional characteristics, EPSs are anticipated to be utilized industrially to remediation of metals, crude oil, and hydrocarbons from contaminated wastewaters, mines, and oil spills. The biotechnological advantages of extremophilic EPSs are more diverse than traditional biopolymers. The present review aims at discussing the mechanisms and strategies for using EPSs from extremophiles in industries and environment bioremediation. Additionally, the potential of EPSs as fascinating biomaterials to mediate biogenic nanoparticles synthesis and treat multicomponent water contaminants is discussed.
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Affiliation(s)
- Aparna Banerjee
- Centro de investigación en Estudios Avanzados del Maule (CIEAM), Vicerrectoría de Investigación Y Posgrado, Universidad Católica del Maule, Talca, Chile
- Centro de Biotecnología de los Recursos Naturales (CENBio), Facultad de Ciencias Agrarias Y Forestales, Universidad Católica del Maule, Talca, Chile
| | - Shrabana Sarkar
- Department of Botany, UGC-Center of Advanced Study, The University of Burdwan, Golapbag, Burdwan, India
| | - Tanvi Govil
- Department of Chemical and Biological Engineering, South Dakota Mines, Rapid City, SD, United States
- Composite and Nanocomposite Advanced Manufacturing – Biomaterials Center, Rapid City, SD, United States
| | - Patricio González-Faune
- Escuela Ingeniería en Biotecnología, Facultad de Ciencias Agrarias Y Forestales, Universidad Católica del Maule, Talca, Chile
| | | | - Rajib Bandopadhyay
- Department of Botany, UGC-Center of Advanced Study, The University of Burdwan, Golapbag, Burdwan, India
| | - David R. Salem
- Department of Botany, UGC-Center of Advanced Study, The University of Burdwan, Golapbag, Burdwan, India
- Department of Chemical and Biological Engineering, South Dakota Mines, Rapid City, SD, United States
- Department of Materials and Metallurgical Engineering, South Dakota Mines, Rapid City, SD, United States
| | - Rajesh K. Sani
- Department of Botany, UGC-Center of Advanced Study, The University of Burdwan, Golapbag, Burdwan, India
- Department of Chemical and Biological Engineering, South Dakota Mines, Rapid City, SD, United States
- BuGReMeDEE Consortium, South Dakota School of Mines and Technology, Rapid City, SD, United States
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Genetic, Genomics, and Responses to Stresses in Cyanobacteria: Biotechnological Implications. Genes (Basel) 2021; 12:genes12040500. [PMID: 33805386 PMCID: PMC8066212 DOI: 10.3390/genes12040500] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/25/2021] [Accepted: 03/25/2021] [Indexed: 02/07/2023] Open
Abstract
Cyanobacteria are widely-diverse, environmentally crucial photosynthetic prokaryotes of great interests for basic and applied science. Work to date has focused mostly on the three non-nitrogen fixing unicellular species Synechocystis PCC 6803, Synechococcus PCC 7942, and Synechococcus PCC 7002, which have been selected for their genetic and physiological interests summarized in this review. Extensive "omics" data sets have been generated, and genome-scale models (GSM) have been developed for the rational engineering of these cyanobacteria for biotechnological purposes. We presently discuss what should be done to improve our understanding of the genotype-phenotype relationships of these models and generate robust and predictive models of their metabolism. Furthermore, we also emphasize that because Synechocystis PCC 6803, Synechococcus PCC 7942, and Synechococcus PCC 7002 represent only a limited part of the wide biodiversity of cyanobacteria, other species distantly related to these three models, should be studied. Finally, we highlight the need to strengthen the communication between academic researchers, who know well cyanobacteria and can engineer them for biotechnological purposes, but have a limited access to large photobioreactors, and industrial partners who attempt to use natural or engineered cyanobacteria to produce interesting chemicals at reasonable costs, but may lack knowledge on cyanobacterial physiology and metabolism.
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Cui J, Xie Y, Sun T, Chen L, Zhang W. Deciphering and engineering photosynthetic cyanobacteria for heavy metal bioremediation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 761:144111. [PMID: 33352345 DOI: 10.1016/j.scitotenv.2020.144111] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 11/22/2020] [Accepted: 11/22/2020] [Indexed: 06/12/2023]
Abstract
Environmental pollution caused by heavy metals has received worldwide attentions due to their ubiquity, poor degradability and easy bioaccumulation in host cells. As one potential solution, photosynthetic cyanobacteria have been considered as promising remediation chassis and widely applied in various bioremediation processes of heavy-metals. Meanwhile, deciphering resistant mechanisms and constructing tolerant chassis towards heavy metals could greatly contribute to the successful application of the cyanobacteria-based bioremediation in the future. In this review, first we summarized recent application of cyanobacteria in heavy metals bioremediation using either live or dead cells. Second, resistant mechanisms and strategies for enhancing cyanobacterial bioremediation of heavy metals were discussed. Finally, potential challenges and perspectives for improving bioremediation of heavy metals by cyanobacteria were presented.
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Affiliation(s)
- Jinyu Cui
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, PR China; Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin 300072, PR China; Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, PR China
| | - Yaru Xie
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, PR China; Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin 300072, PR China; Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, PR China
| | - Tao Sun
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, PR China; Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin 300072, PR China; Center for Biosafety Research and Strategy, Tianjin University, Tianjin 300072, PR China; Law School of Tianjin University, Tianjin 300072, PR China.
| | - Lei Chen
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, PR China; Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin 300072, PR China; Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, PR China.
| | - Weiwen Zhang
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, PR China; Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin 300072, PR China; Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, PR China; Center for Biosafety Research and Strategy, Tianjin University, Tianjin 300072, PR China; Law School of Tianjin University, Tianjin 300072, PR China
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16
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Santos M, Pereira SB, Flores C, Príncipe C, Couto N, Karunakaran E, Cravo SM, Oliveira P, Tamagnini P. Absence of KpsM (Slr0977) Impairs the Secretion of Extracellular Polymeric Substances (EPS) and Impacts Carbon Fluxes in Synechocystis sp. PCC 6803. mSphere 2021; 6:e00003-21. [PMID: 33504656 PMCID: PMC7885315 DOI: 10.1128/msphere.00003-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 01/08/2021] [Indexed: 12/02/2022] Open
Abstract
Many cyanobacteria produce extracellular polymeric substances (EPS), composed mainly of heteropolysaccharides, that play a variety of physiological roles, being crucial for cell protection, motility, and biofilm formation. However, due to their complexity, the EPS biosynthetic pathways as well as their assembly and export mechanisms are still far from being fully understood. Here, we show that the absence of a putative EPS-related protein, KpsM (Slr0977), has a pleiotropic effect on Synechocystis sp. strain PCC 6803 physiology, with a strong impact on the export of EPS and carbon fluxes. The kpsM mutant exhibits a significant reduction of released polysaccharides and a smaller decrease of capsular polysaccharides, but it accumulates more polyhydroxybutyrate (PHB) than the wild type. In addition, this strain shows a light/cell density-dependent clumping phenotype and exhibits an altered protein secretion capacity. Furthermore, the most important structural component of pili, the protein PilA, was found to have a modified glycosylation pattern in the mutant compared to the wild type. Proteomic and transcriptomic analyses revealed significant changes in the mechanisms of energy production and conversion, namely, photosynthesis, oxidative phosphorylation, and carbon metabolism, in response to the inactivation of slr0977 Overall, this work shows for the first time that cells with impaired EPS secretion undergo transcriptomic and proteomic adjustments, highlighting the importance of EPS as a major carbon sink in cyanobacteria. The accumulation of PHB in cells of the mutant, without affecting significantly its fitness/growth rate, points to its possible use as a chassis for the production of compounds of interest.IMPORTANCE Most cyanobacteria produce extracellular polymeric substances (EPS) that fulfill different biological roles depending on the strain/environmental conditions. The interest in the cyanobacterial EPS synthesis/export pathways has been increasing, not only to optimize EPS production but also to efficiently redirect carbon flux toward the production of other compounds, allowing the implementation of industrial systems based on cyanobacterial cell factories. Here, we show that a Synechocystis kpsM (slr0977) mutant secretes less EPS than the wild type, accumulating more carbon intracellularly, as polyhydroxybutyrate. Further characterization showed a light/cell density-dependent clumping phenotype, altered protein secretion, and modified glycosylation of PilA. The proteome and transcriptome of the mutant revealed significant changes, namely, in photosynthesis and carbon metabolism. Altogether, this work provides a comprehensive overview of the impact of kpsM disruption on Synechocystis physiology, highlighting the importance of EPS as a carbon sink and showing how cells adapt when their secretion is impaired, and the redirection of the carbon fluxes.
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Affiliation(s)
- Marina Santos
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IBMC-Instituto de Biologia Celular e Molecular, Universidade do Porto, Porto, Portugal
- Programa Doutoral em Biologia Molecular e Celular (MCbiology), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Sara B Pereira
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IBMC-Instituto de Biologia Celular e Molecular, Universidade do Porto, Porto, Portugal
| | - Carlos Flores
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IBMC-Instituto de Biologia Celular e Molecular, Universidade do Porto, Porto, Portugal
| | - Catarina Príncipe
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IBMC-Instituto de Biologia Celular e Molecular, Universidade do Porto, Porto, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - Narciso Couto
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, United Kingdom
| | - Esther Karunakaran
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, United Kingdom
| | - Sara M Cravo
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), Matosinhos, Portugal
- Laboratório de Química Orgânica, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Paulo Oliveira
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IBMC-Instituto de Biologia Celular e Molecular, Universidade do Porto, Porto, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - Paula Tamagnini
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IBMC-Instituto de Biologia Celular e Molecular, Universidade do Porto, Porto, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
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17
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Biochemical characterization of Nostoc sp. exopolysaccharides and evaluation of potential use in wound healing. Carbohydr Polym 2020; 254:117303. [PMID: 33357870 DOI: 10.1016/j.carbpol.2020.117303] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 10/20/2020] [Accepted: 10/20/2020] [Indexed: 01/16/2023]
Abstract
Exopolysaccharides (EPS) produced by cyanobacteria are complex biomolecules of anionic nature with potential biomedical applications. In this study, the EPS produced by the Nostoc sp. strains PCC7936 and PCC7413 were characterized and evaluated as a biomaterial for new wound dressings. The addition of acetate ions to the culture medium slightly stimulated EPS production, achieving 1463.1 ± 16.0 mgL-1 (PCC7413) and 1372.1 ± 29.0 mgL-1 (PCC7936). Both EPS presented nine monosaccharide residues and a MW > 1000 kDa. The acetate addition changed the monosaccharide molar percentages. FTIR and DLS results confirmed the anionic nature and the presence of sulfate groups in both EPS, which are determinant features for biomedical applications. Both EPS at 1%(w/v) formed gels in the presence of 0.4%(w/v) FeCl3. Results obtained for MTT assay and wound healing in vitro scratch assay revealed hydrogels biocompatibility and ability to promote fibroblast migration and proliferation that was greater in PCC7936. The Nostoc EPS hydrogels presented promising properties to be applied in the treatment of skin injuries.
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18
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Primo E, Bogino P, Cossovich S, Foresto E, Nievas F, Giordano W. Exopolysaccharide II Is Relevant for the Survival of Sinorhizobium meliloti under Water Deficiency and Salinity Stress. Molecules 2020; 25:E4876. [PMID: 33105680 PMCID: PMC7659973 DOI: 10.3390/molecules25214876] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 10/12/2020] [Accepted: 10/20/2020] [Indexed: 11/16/2022] Open
Abstract
Sinorhizobium meliloti is a soil bacterium of great agricultural importance because of its ability to fix atmospheric nitrogen in symbiotic association with alfalfa (Medicago sativa) roots. We looked into the involvement of exopolysaccharides (EPS) in its survival when exposed to different environmental stressors, as well as in bacteria-bacteria and bacteria-substrate interactions. The strains used were wild-type Rm8530 and two strains that are defective in the biosynthesis of EPS II: wild-type Rm1021, which has a non-functional expR locus, and mutant Rm8530 expA. Under stress by water deficiency, Rm8530 remained viable and increased in number, whereas Rm1021 and Rm8530 expA did not. These differences could be due to Rm8530's ability to produce EPS II. Survival experiments under saline stress showed that viability was reduced for Rm1021 but not for Rm8530 or Rm8530 expA, which suggests the existence of some regulating mechanism dependent on a functional expR that is absent in Rm1021. The results of salinity-induced stress assays regarding biofilm-forming capacity (BFC) and autoaggregation indicated the protective role of EPS II. As a whole, our observations demonstrate that EPS play major roles in rhizobacterial survival.
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Affiliation(s)
| | | | | | | | | | - Walter Giordano
- Instituto de Biotecnología Ambiental y Salud (INBIAS), CONICET, Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto (UNRC), Río Cuarto X5804BYA, Córdoba, Argentina; (E.P.); (P.B.); (S.C.); (E.F.); (F.N.)
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Modifying the Cyanobacterial Metabolism as a Key to Efficient Biopolymer Production in Photosynthetic Microorganisms. Int J Mol Sci 2020; 21:ijms21197204. [PMID: 33003478 PMCID: PMC7582838 DOI: 10.3390/ijms21197204] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 09/26/2020] [Accepted: 09/28/2020] [Indexed: 12/22/2022] Open
Abstract
Cyanobacteria are photoautotrophic bacteria commonly found in the natural environment. Due to the ecological benefits associated with the assimilation of carbon dioxide from the atmosphere and utilization of light energy, they are attractive hosts in a growing number of biotechnological processes. Biopolymer production is arguably one of the most critical areas where the transition from fossil-derived chemistry to renewable chemistry is needed. Cyanobacteria can produce several polymeric compounds with high applicability such as glycogen, polyhydroxyalkanoates, or extracellular polymeric substances. These important biopolymers are synthesized using precursors derived from central carbon metabolism, including the tricarboxylic acid cycle. Due to their unique metabolic properties, i.e., light harvesting and carbon fixation, the molecular and genetic aspects of polymer biosynthesis and their relationship with central carbon metabolism are somehow different from those found in heterotrophic microorganisms. A greater understanding of the processes involved in cyanobacterial metabolism is still required to produce these molecules more efficiently. This review presents the current state of the art in the engineering of cyanobacterial metabolism for the efficient production of these biopolymers.
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Zuniga EG, Boateng KKA, Bui NU, Kurnfuli S, Muthana SM, Risser DD. Identification of a hormogonium polysaccharide-specific gene set conserved in filamentous cyanobacteria. Mol Microbiol 2020; 114:597-608. [PMID: 32614458 DOI: 10.1111/mmi.14566] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 06/23/2020] [Indexed: 01/09/2023]
Abstract
Cyanobacteria comprise a phylum defined by the capacity for oxygenic photosynthesis. Members of this phylum are frequently motile as well. Strains that display gliding or twitching motility across semisolid surfaces are powered by a conserved type IV pilus system (T4P). Among the filamentous, heterocyst-forming cyanobacteria, motility is usually confined to specialized filaments known as hormogonia, and requires the deposition of an associated hormogonium polysaccharide (HPS). The genes involved in assembly and export of HPS are largely undefined, and it has been hypothesized that HPS exits the outer membrane via an atypical T4P-driven mechanism. Here, several novel hps loci, primarily encoding glycosyl transferases, are identified. Mutational analysis demonstrates that the majority of these genes are essential for both motility and production of HPS. Notably, most mutant strains accumulate wild-type cellular levels of the major pilin PilA, but not extracellular PilA, indicating dysregulation of the T4P motors, and, therefore, a regulatory interaction between HPS assembly and T4P activity. A co-occurrence analysis of Hps orthologs among cyanobacteria identified an extended set of putative Hps proteins comprising most components of a Wzx/Wzy-type polysaccharide synthesis and export system. This implies that HPS may be secreted through a more canonical pathway, rather than a T4P-mediated mechanism.
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Affiliation(s)
| | | | - Nhi U Bui
- Department of Biology, University of the Pacific, Stockton, CA, USA
| | - Shadi Kurnfuli
- Department of Biology, University of the Pacific, Stockton, CA, USA
| | - Sawsan M Muthana
- Department of Biology, University of the Pacific, Stockton, CA, USA
| | - Douglas D Risser
- Department of Biology, University of the Pacific, Stockton, CA, USA
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Exopolysaccharides from Cyanobacteria: Strategies for Bioprocess Development. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10113763] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Cyanobacteria have the potential to become an industrially sustainable source of functional biopolymers. Their exopolysaccharides (EPS) harbor chemical complexity, which predicts bioactive potential. Although some are reported to excrete conspicuous amounts of polysaccharides, others are still to be discovered. The production of this strain-specific trait can promote carbon neutrality while its intrinsic location can potentially reduce downstream processing costs. To develop an EPS cyanobacterial bioprocess (Cyano-EPS) three steps were explored: the selection of the cyanobacterial host; optimization of production parameters; downstream processing. Studying the production parameters allow us to understand and optimize their response in terms of growth and EPS production though many times it was found divergent. Although the extraction of EPS can be achieved with a certain degree of simplicity, the purification and isolation steps demand experience. In this review, we gathered relevant research on EPS with a focus on bioprocess development. Challenges and strategies to overcome possible drawbacks are highlighted.
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22
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Designer Biopolymers: Self-Assembling Proteins and Nucleic Acids. Int J Mol Sci 2020; 21:ijms21093276. [PMID: 32384600 PMCID: PMC7247343 DOI: 10.3390/ijms21093276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 05/03/2020] [Indexed: 11/25/2022] Open
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