Ajani, PA, Petrou, K, Larsson, ME, Nielsen, DA, Burke, J & Murray, SA 2021, 'Phenotypic trait variability as an indication of adaptive capacity in a cosmopolitan marine diatom.', Environmental microbiology.
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Determining the adaptive capacity of marine phytoplankton is important in predicting changes in phytoplankton responses to ocean warming. Phytoplankton may consist of high levels of standing phenotypic and genetic variability, the basis of rapid evolution; however, few studies have quantified trait variability within and amongst closely related diatom species. Using 35 clonal cultures of the ubiquitous marine diatom Leptocylindrus isolated from six locations, spanning 2000 km of the south-eastern Australian coastline, we found evidence of significant intraspecific morphological and metabolic trait variability, which for 8 of 9 traits (growth rate, biovolume, C:N, silica deposition, silica incorporation rate, chl-a, and photosynthetic efficiency under dark adapted, growth irradiance, and high-light adaptation) were greater within a species than between species. Moreover, only two traits revealed a latitudinal trend with strains isolated from lower latitudes showing significantly higher silicification rates and protein:lipid content compared to their higher latitude counterparts. These data mirror recent studies on diatom intraspecific genetic diversity, which has found comparable levels of genetic diversity at a single site to those thousands of kilometres apart, and provide evidence of a functional role of diatom diversity that will allow for rapid adaptation via ecological selection on standing variation in response to changing conditions.
Commault, AS, Kuzhiumparambil, U, Herdean, A, Fabris, M, Jaramillo-Madrid, AC, Abbriano, RM, Ralph, PJ & Pernice, M 2021, 'Methyl jasmonate and methyl-β-cyclodextrin individually boost triterpenoid biosynthesis in chlamydomonas reinhardtii uvm4', Pharmaceuticals, vol. 14, no. 2, pp. 1-12.
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© 2021 by the authors. Licensee MDPI, Basel, Switzerland. The commercialisation of valuable plant triterpenoids faces major challenges, including low abundance in natural hosts and costly downstream purification procedures. Endeavours to produce these compounds at industrial scale using microbial systems are gaining attention. Here, we report on a strategy to enrich the biomass of the biotechnologically-relevant Chlamydomonas reinhardtii strain UVM4 with valuable triterpenes, such as squalene and (S)-2,3-epoxysqualene. C. reinhardtii UVM4 was subjected to the elicitor compounds methyl jasmonate (MeJA) and methyl-β-cyclodextrine (MβCD) to increase triterpene yields. MeJA treatment triggered oxidative stress, arrested growth, and altered the photosynthetic activity of the cells, while increasing squalene, (S)-2,3-epoxysqualene, and cycloartenol contents. Applying MβCD to cultures of C. reinhardtii lead to the sequestration of the two main sterols (ergosterol and 7-dehydroporiferasterol) into the growth medium and the intracellular accumulation of the intermediate cycloartenol, without compromising cell growth. When MβCD was applied in combination with MeJA, it counteracted the negative effects of MeJA on cell growth and physiology, but no synergistic effect on triterpene yield was observed. Together, our findings provide strategies for the triterpene enrichment of microalgal biomass and medium.
Cziesielski, MJ, Duarte, CM, Aalismail, N, Al-Hafedh, Y, Anton, A, Baalkhuyur, F, Baker, AC, Balke, T, Baums, IB, Berumen, M, Chalastani, VI, Cornwell, B, Daffonchio, D, Diele, K, Farooq, E, Gattuso, JP, He, S, Lovelock, CE, Mcleod, E, Macreadie, PI, Marba, N, Martin, C, Muniz-Barreto, M, Kadinijappali, KP, Prihartato, P, Rabaoui, L, Saderne, V, Schmidt-Roach, S, Suggett, DJ, Sweet, M, Statton, J, Teicher, S, Trevathan-Tackett, SM, Joydas, TV, Yahya, R & Aranda, M 2021, 'Investing in Blue Natural Capital to Secure a Future for the Red Sea Ecosystems', Frontiers in Marine Science, vol. 7.
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© Copyright © 2021 Cziesielski, Duarte, Aalismail, Al-Hafedh, Anton, Baalkhuyur, Baker, Balke, Baums, Berumen, Chalastani, Cornwell, Daffonchio, Diele, Farooq, Gattuso, He, Lovelock, Mcleod, Macreadie, Marba, Martin, Muniz-Barreto, Kadinijappali, Prihartato, Rabaoui, Saderne, Schmidt-Roach, Suggett, Sweet, Statton, Teicher, Trevathan-Tackett, Joydas, Yahya and Aranda. For millennia, coastal and marine ecosystems have adapted and flourished in the Red Sea’s unique environment. Surrounded by deserts on all sides, the Red Sea is subjected to high dust inputs and receives very little freshwater input, and so harbors a high salinity. Coral reefs, seagrass meadows, and mangroves flourish in this environment and provide socio-economic and environmental benefits to the bordering coastlines and countries. Interestingly, while coral reef ecosystems are currently experiencing rapid decline on a global scale, those in the Red Sea appear to be in relatively better shape. That said, they are certainly not immune to the stressors that cause degradation, such as increasing ocean temperature, acidification and pollution. In many regions, ecosystems are already severely deteriorating and are further threatened by increasing population pressure and large coastal development projects. Degradation of these marine habitats will lead to environmental costs, as well as significant economic losses. Therefore, it will result in a missed opportunity for the bordering countries to develop a sustainable blue economy and integrate innovative nature-based solutions. Recognizing that securing the Red Sea ecosystems’ future must occur in synergy with continued social and economic growth, we developed an action plan for the conservation, restoration, and growth of marine environments of the Red Sea. We then investigated the level of resources for financial and economic investment that may incentivize these activities. This study presents a set of commercially viable financial investment strategie...
Garczarek, L, Guyet, U, Doré, H, Farrant, GK, Hoebeke, M, Brillet-Guéguen, L, Bisch, A, Ferrieux, M, Siltanen, J, Corre, E, Le Corguillé, G, Ratin, M, Pitt, FD, Ostrowski, M, Conan, M, Siegel, A, Labadie, K, Aury, J-M, Wincker, P, Scanlan, DJ & Partensky, F 2021, 'Cyanorak v2.1: a scalable information system dedicated to the visualization and expert curation of marine and brackish picocyanobacteria genomes.', Nucleic acids research, vol. 49, no. D1, pp. D667-D676.
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Cyanorak v2.1 (http://www.sb-roscoff.fr/cyanorak) is an information system dedicated to visualizing, comparing and curating the genomes of Prochlorococcus, Synechococcus and Cyanobium, the most abundant photosynthetic microorganisms on Earth. The database encompasses sequences from 97 genomes, covering most of the wide genetic diversity known so far within these groups, and which were split into 25,834 clusters of likely orthologous groups (CLOGs). The user interface gives access to genomic characteristics, accession numbers as well as an interactive map showing strain isolation sites. The main entry to the database is through search for a term (gene name, product, etc.), resulting in a list of CLOGs and individual genes. Each CLOG benefits from a rich functional annotation including EggNOG, EC/K numbers, GO terms, TIGR Roles, custom-designed Cyanorak Roles as well as several protein motif predictions. Cyanorak also displays a phyletic profile, indicating the genotype and pigment type for each CLOG, and a genome viewer (Jbrowse) to visualize additional data on each genome such as predicted operons, genomic islands or transcriptomic data, when available. This information system also includes a BLAST search tool, comparative genomic context as well as various data export options. Altogether, Cyanorak v2.1 constitutes an invaluable, scalable tool for comparative genomics of ecologically relevant marine microorganisms.
Hudspith, M, Rix, L, Achlatis, M, Bougoure, J, Guagliardo, P, Clode, PL, Webster, NS, Muyzer, G, Pernice, M & de Goeij, JM 2021, 'Subcellular view of host-microbiome nutrient exchange in sponges: insights into the ecological success of an early metazoan-microbe symbiosis.', Microbiome, vol. 9, no. 1, p. 44.
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Background
Sponges are increasingly recognised as key ecosystem engineers in many aquatic habitats. They play an important role in nutrient cycling due to their unrivalled capacity for processing both dissolved and particulate organic matter (DOM and POM) and the exceptional metabolic repertoire of their diverse and abundant microbial communities. Functional studies determining the role of host and microbiome in organic nutrient uptake and exchange, however, are limited. Therefore, we coupled pulse-chase isotopic tracer techniques with nanoscale secondary ion mass spectrometry (NanoSIMS) to visualise the uptake and translocation of
13C- and
15N-labelled dissolved and particulate organic food at subcellular level in the high microbial abundance sponge Plakortis angulospiculatus and the low microbial abundance sponge Halisarca caerulea.
Results
The two sponge species showed significant enrichment of DOM- and POM-derived
13C and
15N into their tissue over time. Microbial symbionts were actively involved in the assimilation of DOM, but host filtering cells (choanocytes) appeared to be the primary site of DOM and POM uptake in both sponge species overall, via pinocytosis and phagocytosis, respectively. Translocation of carbon and nitrogen from choanocytes to microbial symbionts occurred over time, irrespective of microbial abundance, reflecting recycling of host waste products by the microbiome.
Conclusions
Here, we provide empirical evidence indicating that the prokaryotic communities of a high and a low microbial abundance sponge obtain nutritional benefits from their host-associated lifestyle. The metabolic interaction between the highly efficient filter-feeding host and its microbial symbionts likely provides a competitive advantage to the sponge holobiont in the oligotrophic environments in which they thrive, by retaining and recycling limiting nutrients. Sponges present a unique model to link nutr...
Labeeuw, L, Commault, AS, Kuzhiumparambil, U, Emmerton, B, Nguyen, LN, Nghiem, LD & Ralph, PJ 2021, 'A comprehensive analysis of an effective flocculation method for high quality microalgal biomass harvesting', SCIENCE OF THE TOTAL ENVIRONMENT, vol. 752.
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Laiolo, L, Matear, R, Soja-Woźniak, M, Suggett, DJ, Hughes, DJ, Baird, ME & Doblin, MA 2021, 'Modelling the impact of phytoplankton cell size and abundance on inherent optical properties (IOPs) and a remotely sensed chlorophyll-a product', Journal of Marine Systems, vol. 213.
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© 2020 Elsevier B.V. Ocean colour data are commonly used to quantify primary production, study phytoplankton dynamics and calibrate marine models, thus understanding the origin of errors in the retrieved chlorophyll-a (Chl-a) product is critical. One source of uncertainty in retrieved Chl-a products can be related to large photosynthetic cells, characterised by lower mass-specific absorption coefficients due to increased packaging effect. Here, we explore the relationship between phytoplankton size structure and an ocean colour product using optical simulations and in situ observations. Specifically, we use an optical model to explore how phytoplankton cell size and abundance influence phytoplankton absorption and backscattering coefficients and the implication this has for water leaving radiance and the estimated Chl-a derived from satellite ocean colour. The optical model simulations show phytoplankton cell size has a significant impact on the remote-sensing reflectance, with Chl-a packaged in 5 to 10 μm cells resulting in about 54 to 76% the simulated ocean colour Chl-a compared to 1 μm cells, as determined by an algorithm that converts reflectances to Chl-a. To support optical simulations, size-fractionated Chl-a samples were collected from several water masses to investigate the phytoplankton size contribution (i.e., < 2 μm, 2–10 μm and > 10 μm) to the total Chl-a. We focused on the offshore eastern Australian ocean region, largely characterised by oligotrophic waters in which phytoplankton dominate the optical properties of the water column. Of the 22 stations sampled, a total of ten in situ size fractionated Chl-a measurements were matched-up with the corresponding clear-sky satellite Chl-a product. The matched-up points revealed a systematic underestimation of in situ Chl-a. With the low amount of data, it was not possible to statistically relate the satellite underestimation to a specific phytoplankton size class, but the observations showed that the lar...
Leal, E, de Beyer, L, O'Connor, W, Dove, M, Ralph, PJ & Pernice, M 2021, 'Production optimisation of Tisochrysis lutea as a live feed for juvenile Sydney rock oysters, Saccostrea glomerata, using large-scale photobioreactors', Aquaculture, vol. 533.
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© 2020 Elsevier B.V. The aquaculture industry uses microalgae as a live feed for juvenile oysters in hatcheries to meet their nutritional requirements, including their need for several essential Poly Unsaturated Fatty Acids (PUFAs) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The mass culture of microalgae is not only a major bottleneck for the production of juvenile oysters, but also a significant cost, accounting for 20–50% of hatchery operating costs. Currently, low biomass concentrations, high production costs and poor cultivation systems limit the quantity and quality of microalgae feed. This study focused on Tisochrysis lutea, a microalgae species commonly used in aquaculture, and we assessed the potential of photobioreactors with an improved light source and CO2 input to increase biomass production and improve biochemical composition of algal feed. Two photobioreactor systems were compared: the current industry set up (DPI) comprising fluorescent lighting and minimal CO2 input versus an optimized system utilising LEDs and increased CO2. Cultures of T. lutea were monitored over a 12-day growth period and harvested on day 14 for biochemical analysis. Final cell density was significantly higher in the optimized system relative to the conventional culture systems (6.2 × 106 cells / mL versus 3.7 × 106 cells / mL, respectively). The biochemical profile of T. lutea was not significantly different between the two photobioreactors systems. The algal biomass produced during this comparative experiment was used in a feeding trial on oyster spat, Saccostrea glomerata. Spat fed with algae produced in optimized vs conventional photobioreactors showed no significant difference in growth, but oyster spat fed with T. lutea grown in optimized photobioreactors did show a significant increase in their EPA content. Overall, our results contribute to our understanding of how altered culture conditions affect microalgal production and biochemical composit...
Maire, J, Girvan, SK, Barkla, SE, Perez-Gonzalez, A, Suggett, DJ, Blackall, LL & van Oppen, MJH 2021, 'Intracellular bacteria are common and taxonomically diverse in cultured and in hospite algal endosymbionts of coral reefs', ISME Journal.
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© 2021, The Author(s). Corals house a variety of microorganisms which they depend on for their survival, including endosymbiotic dinoflagellates (Symbiodiniaceae) and bacteria. While cnidarian–microorganism interactions are widely studied, Symbiodiniaceae–bacteria interactions are only just beginning to receive attention. Here, we describe the localization and composition of the bacterial communities associated with cultures of 11 Symbiodiniaceae strains from nine species and six genera. Three-dimensional confocal laser scanning and electron microscopy revealed bacteria are present inside the Symbiodiniaceae cells as well as closely associated with their external cell surface. Bacterial pure cultures and 16S rRNA gene metabarcoding from Symbiodiniaceae cultures highlighted distinct and highly diverse bacterial communities occur intracellularly, closely associated with the Symbiodiniaceae outer cell surface and loosely associated (i.e., in the surrounding culture media). The intracellular bacteria are highly conserved across Symbiodiniaceae species, suggesting they may be involved in Symbiodiniaceae physiology. Our findings provide unique new insights into the biology of Symbiodiniaceae.
Polerecky, L, Masuda, T, Eichner, M, Rabouille, S, Vancová, M, Kienhuis, MVM, Bernát, G, Bonomi-Barufi, J, Campbell, DA, Claquin, P, Červený, J, Giordano, M, Kotabová, E, Kromkamp, J, Lombardi, AT, Lukeš, M, Prášil, O, Stephan, S, Suggett, D, Zavřel, T & Halsey, KH 2021, 'Temporal Patterns and Intra- and Inter-Cellular Variability in Carbon and Nitrogen Assimilation by the Unicellular Cyanobacterium Cyanothece sp. ATCC 51142', Frontiers in Microbiology, vol. 12.
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© Copyright © 2021 Polerecky, Masuda, Eichner, Rabouille, Vancová, Kienhuis, Bernát, Bonomi-Barufi, Campbell, Claquin, Červený, Giordano, Kotabová, Kromkamp, Lombardi, Lukeš, Prášil, Stephan, Suggett, Zavřel and Halsey. Unicellular nitrogen fixing cyanobacteria (UCYN) are abundant members of phytoplankton communities in a wide range of marine environments, including those with rapidly changing nitrogen (N) concentrations. We hypothesized that differences in N availability (N2 vs. combined N) would cause UCYN to shift strategies of intracellular N and C allocation. We used transmission electron microscopy and nanoscale secondary ion mass spectrometry imaging to track assimilation and intracellular allocation of 13C-labeled CO2 and 15N-labeled N2 or NO3 at different periods across a diel cycle in Cyanothece sp. ATCC 51142. We present new ideas on interpreting these imaging data, including the influences of pre-incubation cellular C and N contents and turnover rates of inclusion bodies. Within cultures growing diazotrophically, distinct subpopulations were detected that fixed N2 at night or in the morning. Additional significant within-population heterogeneity was likely caused by differences in the relative amounts of N assimilated into cyanophycin from sources external and internal to the cells. Whether growing on N2 or NO3, cells prioritized cyanophycin synthesis when N assimilation rates were highest. N assimilation in cells growing on NO3 switched from cyanophycin synthesis to protein synthesis, suggesting that once a cyanophycin quota is met, it is bypassed in favor of protein synthesis. Growth on NO3 also revealed that at night, there is a very low level of CO2 assimilation into polysaccharides simultaneous with their catabolism for protein synthesis. This study revealed multiple, detailed mechanisms underlying C and N management in Cyanothece that facilitate its success in dynamic aquatic environments.
Ros, M, Suggett, DJ, Edmondson, J, Haydon, T, Hughes, DJ, Kim, M, Guagliardo, P, Bougoure, J, Pernice, M, Raina, JB & Camp, EF 2021, 'Symbiont shuffling across environmental gradients aligns with changes in carbon uptake and translocation in the reef-building coral Pocillopora acuta', Coral Reefs.
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© 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature. Symbiosis between reef-building corals and unicellular algae (Symbiodiniaceae) fuels the growth and productivity of corals reefs. Capacity for Symbiodiniaceae to fix inorganic carbon (Ci) and translocate carbon compounds to the host is central to coral health, but how these processes change for corals thriving in environmental extremes remains largely unresolved. We investigate how a model coral—Pocillopora acuta—persists from a reef habitat into an adjacent extreme mangrove lagoon on the Great Barrier Reef. We combine respirometry and photophysiology measurements, Symbiodiniaceae genotyping, and 13C labelling to compare P. acuta metabolic performance across habitats, in relation to the Ci uptake and translocation capacity by symbionts’ autotrophy. We show that differences in P. acuta metabolic strategies across habitats align with a shift in dominant host-associated Symbiodiniaceae taxon, from Cladocopium in the reef to Durusdinium in the mangroves. This shift corresponded with a change in “photosynthetic strategy”, with P. acuta in the mangroves utilising absorbed light for photochemistry over non-photochemical quenching. Mangrove corals translocated similar proportions of carbon compared to the reefs, despite a lower Ci uptake. These trends indicate that coral survival in mangrove environments occurs through sustained translocation rate of organic compounds from coral symbionts to host.
Rouze, H, Galand, PE, Medina, M, Bongaerts, P, Pichon, M, Perez-Rosales, G, Torda, G, Moya, A, Raina, J-B & Hedouin, L 2021, 'Symbiotic associations of the deepest recorded photosynthetic scleractinian coral (172 m depth)', ISME JOURNAL, vol. 15, no. 5, pp. 1564-1568.
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Sutherland, DL, Burke, J & Ralph, PJ 2021, 'Trade-offs between effluent quality and ammonia volatilisation with CO2 augmented microalgal treatment of anaerobically digested food-waste centrate.', Journal of environmental management, vol. 277, pp. 111398-111398.
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Diversion of food waste from landfill disposal to waste-to-energy facilities has become both an environmentally and economically viable option to support the circular bioeconomy. However, the liquid centrate produced during anaerobic digestion is high in total ammonia, with concentrations ~2000 g m-3, and can release gaseous emissions, including ammonia, methane, CO2 and nitrous oxide, to the atmosphere. Further treatment is required before discharge to sewer, or to the environment. Microalgal wastewater treatment systems augmented with CO2 offer a promising and cost-effective treatment solution for reducing both total ammonia concentrations and ammonia volatilisation. In this study, we investigate the effects of augmenting CO2 on nutrient removal and specifically nitrogen losses, as well as biomass productivity under two difference hydraulic retention times (HRT). Both CO2 addition and HRT affect nitrogen losses, with the percentage removal of total ammonia significantly lower (p < 0.01) when CO2 was added to the treatments, while increased HRT significantly increased (p < 0.05) total ammonia percentage removal. Total nitrogen budgets showed significantly lower (p < 0.01) abiotic nitrogen losses from the system when CO2 was added to the culture but at the expense of effluent quality. Both total suspended solids and volatile suspended solids significantly increased (p < 0.01) under longer HRT (8 days), with CO2 addition, while chlorophyll-a biomass significantly increased (p < 0.01) on longer HRT, regardless of CO2 addition. These results demonstrate that, while CO2 augmentation helped to mitigate ammonia losses to atmosphere, the trade-off was poorer effluent quality. Coupling CO2 augmentation with longer HRT increased biomass production and nutrient removal efficiency. This study provides an insight into how simple operational changes can alleviate some of the trade-offs between atmospheric losses and effluent quality. However, in order to manage the trade-off ...
Vu, HP, Nguyen, LN, Vu, MT, Labeeuw, L, Emmerton, B, Commault, AS, Ralph, PJ, Mahlia, TM & Nghiem, LD 2021, 'Harvesting Porphyridium purpureum using polyacrylamide polymers and alkaline bases and their impact on biomass quality', SCIENCE OF THE TOTAL ENVIRONMENT, vol. 755.
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Windhagauer, M, Abbriano, RM, Ashworth, J, Barolo, L, Jaramillo-Madrid, AC, Pernice, M & Doblin, MA 2021, 'Characterisation of novel regulatory sequences compatible with modular assembly in the diatom Phaeodactylum tricornutum', ALGAL RESEARCH-BIOMASS BIOFUELS AND BIOPRODUCTS, vol. 53.
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