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Pushpakumara BLDU, Tandon K, Willis A, Verbruggen H. The Bacterial Microbiome of the Coral Skeleton Algal Symbiont Ostreobium Shows Preferential Associations and Signatures of Phylosymbiosis. MICROBIAL ECOLOGY 2023; 86:2032-2046. [PMID: 37002423 PMCID: PMC10497448 DOI: 10.1007/s00248-023-02209-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 03/16/2023] [Indexed: 06/19/2023]
Abstract
Ostreobium, the major algal symbiont of the coral skeleton, remains understudied despite extensive research on the coral holobiont. The enclosed nature of the coral skeleton might reduce the dispersal and exposure of residing bacteria to the outside environment, allowing stronger associations with the algae. Here, we describe the bacterial communities associated with cultured strains of 5 Ostreobium clades using 16S rRNA sequencing. We shed light on their likely physical associations by comparative analysis of three datasets generated to capture (1) all algae associated bacteria, (2) enriched tightly attached and potential intracellular bacteria, and (3) bacteria in spent media. Our data showed that while some bacteria may be loosely attached, some tend to be tightly attached or potentially intracellular. Although colonised with diverse bacteria, Ostreobium preferentially associated with 34 bacterial taxa revealing a core microbiome. These bacteria include known nitrogen cyclers, polysaccharide degraders, sulphate reducers, antimicrobial compound producers, methylotrophs, and vitamin B12 producers. By analysing co-occurrence networks of 16S rRNA datasets from Porites lutea and Paragoniastrea australensis skeleton samples, we show that the Ostreobium-bacterial associations present in the cultures are likely to also occur in their natural environment. Finally, our data show significant congruence between the Ostreobium phylogeny and the community composition of its tightly associated microbiome, largely due to the phylosymbiotic signal originating from the core bacterial taxa. This study offers insight into the Ostreobium microbiome and reveals preferential associations that warrant further testing from functional and evolutionary perspectives.
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Affiliation(s)
| | - Kshitij Tandon
- School of Biosciences, University of Melbourne, Victoria, 3010, Australia
| | - Anusuya Willis
- Australian National Algae Culture Collection, CSIRO, Tasmania, 7000, Victoria, Australia
| | - Heroen Verbruggen
- School of Biosciences, University of Melbourne, Victoria, 3010, Australia
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Pushpakumara BLDU, Tandon K, Willis A, Verbruggen H. Unravelling microalgal-bacterial interactions in aquatic ecosystems through 16S rRNA gene-based co-occurrence networks. Sci Rep 2023; 13:2743. [PMID: 36797257 PMCID: PMC9935533 DOI: 10.1038/s41598-023-27816-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 01/09/2023] [Indexed: 02/18/2023] Open
Abstract
Interactions between microalgae and bacteria can directly influence the global biogeochemical cycles but the majority of such interactions remain unknown. 16S rRNA gene-based co-occurrence networks have potential to help identify microalgal-bacterial interactions. Here, we used data from 10 Earth microbiome projects to identify potential microalgal-bacterial associations in aquatic ecosystems. A high degree of clustering was observed in microalgal-bacterial modules, indicating densely connected neighbourhoods. Proteobacteria and Bacteroidetes predominantly co-occurred with microalgae and represented hubs of most modules. Our results also indicated that species-specificity may be a global characteristic of microalgal associated microbiomes. Several previously known associations were recovered from our network modules, validating that biologically meaningful results can be inferred using this approach. A range of previously unknown associations were recognised such as co-occurrences of Bacillariophyta with uncultured Planctomycetes OM190 and Deltaproteobacteria order NB1-j. Planctomycetes and Verrucomicrobia were identified as key associates of microalgae due to their frequent co-occurrences with several microalgal taxa. Despite no clear taxonomic pattern, bacterial associates appeared functionally similar across different environments. To summarise, we demonstrated the potential of 16S rRNA gene-based co-occurrence networks as a hypothesis-generating framework to guide more focused research on microalgal-bacterial associations.
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Affiliation(s)
| | - Kshitij Tandon
- School of Biosciences, University of Melbourne, Melbourne, VIC, Australia
| | - Anusuya Willis
- Australian National Algae Culture Collection, CSIRO, Hobart, TAS, 7000, Australia
| | - Heroen Verbruggen
- School of Biosciences, University of Melbourne, Melbourne, VIC, Australia.
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Microalgae as Potential Sources of Bioactive Compounds for Functional Foods and Pharmaceuticals. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12125877] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Microalgae are an untapped source of bioactive compounds with various biotechnological applications. Several species are industrially produced and commercialized for the feed or cosmetic industries, however, other applications in the functional food and pharmaceutical markets can be foreseen. In this study, nine industrial/commercial species were evaluated for in vitro antioxidant, calcium-chelating, anti-tumoral, and anti-inflammatory activities. The most promising extracts were fractionated yielding several promising fractions namely, of Tetraselmis striata CTP4 with anti-inflammatory activity (99.0 ± 0.8% reduction in TNF-α production in LPS stimulated human macrophages at 50 µg/mL), of Phaeodactylum Tricornutum with cytotoxicity towards cancerous cell lines (IC50 = 22.3 ± 1.8 μg/mL and 27.5 ± 1.6 μg/mL for THP-1 and HepG2, respectively) and of Porphyridium sp. and Skeletonema sp. with good chelating activity for iron, copper and calcium (IC50 = 0.047, 0.272, 0.0663 mg/mL and IC50 = 0.055, 0.240, 0.0850 mg/mL, respectively). These fractions were chemically characterized by GC–MS after derivatization and in all, fatty acids at various degrees of unsaturation were the most abundant compounds. Some of the species under study proved to be potentially valuable sources of antioxidant, metal chelators, anti-tumoral and anti-inflammatory compounds with possible application in the functional food and pharmaceutical industries.
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Rachidi F, Benhima R, Kasmi Y, Sbabou L, Arroussi HE. Evaluation of microalgae polysaccharides as biostimulants of tomato plant defense using metabolomics and biochemical approaches. Sci Rep 2021; 11:930. [PMID: 33441599 PMCID: PMC7806925 DOI: 10.1038/s41598-020-78820-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 12/01/2020] [Indexed: 01/29/2023] Open
Abstract
Microalgal polysaccharides (PSs) may be an effective elicitor agent that can efficiently protect plants against biotic stresses. In this study, wee investigates, the effect of PS obtained from microalgae and cyanobacteria (D. salina MS002, P. tricorontum MS023, Porphyridium sp. MS081, Desmodesmus sp., D. salina MS067 and A. platensis MS001) on the biochemical and metabolomics markers linked to defense pathways in tomato plants. The phenylalanine ammonia lyase (PAL), chitinase, 1,3-beta-glucanase and peroxidase (POX) activities have been improved in tomato plants leaves treated by polysaccharides extracted from P. triocnutum (238.26%); Desmodesmus sp. (19.95%); P. triocnutum (137.50%) and Porphyridium sp. (47.28%) respectively. For proteins, polyphenols and H2O2, the maximum effect was induced by D. salina 067 (55.01%), Porphyridium sp. (3.97%) and A. platensis (35.08%) respectively. On the other hand, Gas Chromatography-mass spectrometry (GC-MS) metabolomics analysis showed that PSs induced the modification of metabolite profile involved in the wax construction of tomato leaves, such as fatty acids, alkanes, alkenes and phytosterol. PS treatments improved the accumulation of fatty acids C16:3, C18:2 and C18:3 released from the membrane lipids as precursors of oxylipin biosynthesis which are signaling molecules of plant defense. In addition, PS treatment induced the accumulation of C18:0 and Azelaic acid which is a regulator of salicylic acid-dependent systemic acquired resistance. However, molecular and metabolic studies can determine more precisely the mode of action of microalgal polysaccharides as biostimulants/elicitors plant defense.
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Affiliation(s)
- Farid Rachidi
- Green Biotechnology Center, MASCIR (Moroccan Foundation for Advanced Science, Innovation & Research), Rue Mohamed Al Jazouli Madinat Al Irfane, 10 100, Rabat, Morocco
- Microbiology and Molecular Biology Team, Center of Plant and Microbial Biotechnology, Biodiversity and Environment, Faculty of Sciences, Mohammed V University, 4 Avenue Ibn Battouta, B.P. 1014, Rabat, Morocco
| | - Redouane Benhima
- Green Biotechnology Center, MASCIR (Moroccan Foundation for Advanced Science, Innovation & Research), Rue Mohamed Al Jazouli Madinat Al Irfane, 10 100, Rabat, Morocco
| | - Yassine Kasmi
- Green Biotechnology Center, MASCIR (Moroccan Foundation for Advanced Science, Innovation & Research), Rue Mohamed Al Jazouli Madinat Al Irfane, 10 100, Rabat, Morocco
| | - Laila Sbabou
- Microbiology and Molecular Biology Team, Center of Plant and Microbial Biotechnology, Biodiversity and Environment, Faculty of Sciences, Mohammed V University, 4 Avenue Ibn Battouta, B.P. 1014, Rabat, Morocco
| | - Hicham El Arroussi
- Green Biotechnology Center, MASCIR (Moroccan Foundation for Advanced Science, Innovation & Research), Rue Mohamed Al Jazouli Madinat Al Irfane, 10 100, Rabat, Morocco.
- Agrobiosciences Program, University Mohamed 6 polytechnic (UM6P), Benguerir, Morocco.
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Mitchell RJ, Mun W, Mabekou SS, Jang H, Choi SY. Compounds affecting predation by and viability of predatory bacteria. Appl Microbiol Biotechnol 2020; 104:3705-3713. [DOI: 10.1007/s00253-020-10530-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 03/01/2020] [Accepted: 03/05/2020] [Indexed: 12/13/2022]
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Kraft K, Alum A, Abbaszadegan M. Environmental algal phage isolates and their impact on production potential for food and biofuel applications. J Appl Microbiol 2019; 128:182-190. [PMID: 31606918 DOI: 10.1111/jam.14487] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 08/07/2019] [Accepted: 09/14/2019] [Indexed: 11/28/2022]
Abstract
AIMS The United States Department of Energy is aiming to bring microalgal biofuels into commercial use by 2030 at the price of $3 per gasoline gallon equivalent. Large-scale production of biofuel faces many challenges including naturally occurring algal phages; and characterizing this threat is the aim of this study. METHODS AND RESULTS Bench-scale experiments were performed to study the impact of viral infectivity on the production of microalgal in bioreactors. All environmental samples were tested positive for algal phages which showed various levels of infectivity against Synechocystis PCC 6803 and the environmental isolates of microalgae. The viral attachment to algal cells was observed under transmission electron microscopy (TEM) and to determine the shape and size of the viral particles. All the viruses detected were c. 50-60 nm icosahedral particles. Viral infection resulted in 48% reduction in the biomass of the infected algal culture in 22 days. CONCLUSIONS This study has lead to the conclusion that the microalgal phages prevalent in natural environment may cause infections in broad range of microalgae used for biofuel production. SIGNIFICANCE AND IMPACT OF THE STUDY This study has detected and quantified the phages that can infect algal populations in natural freshwater habitats and laboratory cultures of microalgal strains. The impact of viral threat to health of commercial algal production operations has been identified in this study.
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Affiliation(s)
- K Kraft
- Civil, Environmental & Sustainable Engineering, School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ, USA
| | - A Alum
- Civil, Environmental & Sustainable Engineering, School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ, USA
| | - M Abbaszadegan
- Civil, Environmental & Sustainable Engineering, School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ, USA
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Attalah S, Waller P, Steichen S, Brown C, Mehdipour Y, Ogden K, Brown J. Cost minimization of deoxygenation for control of Vampirovibrio chlorellavorus in Chlorella sorokiniana cultures. ALGAL RES 2019. [DOI: 10.1016/j.algal.2019.101615] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Cho G, Kwon J, Soh SM, Jang H, Mitchell RJ. Sensitivity of predatory bacteria to different surfactants and their application to check bacterial predation. Appl Microbiol Biotechnol 2019; 103:8169-8178. [PMID: 31407038 DOI: 10.1007/s00253-019-10069-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 07/24/2019] [Accepted: 07/26/2019] [Indexed: 12/27/2022]
Abstract
We evaluated the toxicity of surfactants against different predatory bacteria. Tests with Bdellovibrio bacteriovorus HD100 and SDS, an anionic surfactant, showed the predator was very sensitive; 0.02% SDS completely killed the predatory population (7-log loss; < 10 PFU/ml remaining) both when free-swimming or within the bdelloplast, i.e., intraperiplasmic. Similar results were also observed with B. bacteriovorus 109J and Peredibacter starrii. In contrast, none of the prey (E. coli, Klebsiella pneumoniae, Acinetobacter baumannii, or Pseudomonas sp. DSM 50906) viabilities were negatively affected by SDS. Triton X-100, a nonionic surfactant, was slightly less toxic towards B. bacteriovorus HD100 (viability loss of only 4-log), while two cationic surfactants, i.e., benzalkonium chloride (BZC) and cetyltrimethylammonium bromide (CTAB), were toxic towards both the predator and prey. Based on the above findings, we tested the potential use of SDS as a means to control predation. Addition of 0.02% SDS immediately halted predation based upon the prey bioluminescence, which leveled off and remained steady. This was confirmed using the predator viabilities; no predators were found in any of the samples where SDS was added. Consequently, low concentrations of SDS can be used as a simple means to control B. bacteriovorus HD100 activities.
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Affiliation(s)
- Gayoung Cho
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, South Korea
| | - Jisoo Kwon
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, South Korea
| | - Sandrine Mabekou Soh
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, South Korea
| | - Hyochan Jang
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, South Korea
| | - Robert J Mitchell
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, South Korea.
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Attalah S, Waller P, Steichen S, Gao S, Brown C, Ogden K, Brown J. Application of deoxygenation-aeration cycling to control the predatory bacterium Vampirovibrio chlorellavorus in Chlorella sorokiniana cultures. ALGAL RES 2019. [DOI: 10.1016/j.algal.2019.101427] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Saha M, Goecke F, Bhadury P. Minireview: algal natural compounds and extracts as antifoulants. JOURNAL OF APPLIED PHYCOLOGY 2017; 30:1859-1874. [PMID: 29899600 PMCID: PMC5982446 DOI: 10.1007/s10811-017-1322-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Revised: 10/17/2017] [Accepted: 10/17/2017] [Indexed: 05/02/2023]
Abstract
Marine biofouling is a paramount phenomenon in the marine environment and causes serious problems to maritime industries worldwide. Marine algae are known to produce a wide variety of chemical compounds with antibacterial, antifungal, antialgal, and anti-macrofouling properties, inhibiting the settlement and growth of other marine fouling organisms. Significant investigations and progress have been made in this field in the last two decades and several antifouling extracts and compounds have been isolated from micro- and macroalgae. In this minireview, we have summarized and evaluated antifouling compounds isolated and identified from macroalgae and microalgae between January 2010 and June 2016. Future directions for their commercialization through metabolic engineering and industrial scale up have been discussed. Upon comparing biogeographical regions, investigations from Southeast Asian waters were found to be rather scarce. Thus, we have also discussed the need to conduct more chemical ecology based research in relatively less explored areas with high algal biodiversity like Southeast Asia.
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Affiliation(s)
- Mahasweta Saha
- Benthic Ecology, Helmholtz Center for Ocean Research, Düsternbrooker weg, 24105 Kiel, Germany
- Present Address: School of Biological Science, University of Essex, Colchester, CO 43 SQ, UK
| | - Franz Goecke
- Department of Plant and Environmental Science (IPV), Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Punyasloke Bhadury
- Integrative Taxonomy and Microbial Ecology Research Group, Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, Nadia, West Bengal 741246 India
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