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Cai L, Li H, Deng J, Zhou R, Zeng Q. Biological interactions with Prochlorococcus: implications for the marine carbon cycle. Trends Microbiol 2024; 32:280-291. [PMID: 37722980 DOI: 10.1016/j.tim.2023.08.011] [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: 04/29/2023] [Revised: 08/25/2023] [Accepted: 08/28/2023] [Indexed: 09/20/2023]
Abstract
The unicellular picocyanobacterium Prochlorococcus is the most abundant photoautotroph and contributes substantially to global CO2 fixation. In the vast euphotic zones of the open ocean, Prochlorococcus converts CO2 into organic compounds and supports diverse organisms, forming an intricate network of interactions that regulate the magnitude of carbon cycling and storage in the ocean. An understanding of the biological interactions with Prochlorococcus is critical for accurately estimating the contributions of Prochlorococcus and interacting organisms to the marine carbon cycle. This review synthesizes the primary production contributed by Prochlorococcus in the global ocean. We outline recent progress on the interactions of Prochlorococcus with heterotrophic bacteria, phages, and grazers that multifacetedly determine Prochlorococcus carbon production and fate. We discuss that climate change might affect the biological interactions with Prochlorococcus and thus the marine carbon cycle.
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Affiliation(s)
- Lanlan Cai
- Department of Ocean Science, The Hong Kong University of Science and Technology, Hong Kong, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
| | - Haofu Li
- Department of Ocean Science, The Hong Kong University of Science and Technology, Hong Kong, China; HKUST Shenzhen-Hong Kong Collaborative Innovation Research Institute, Shenzhen, China
| | - Junwei Deng
- Department of Ocean Science, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Ruiqian Zhou
- Department of Ocean Science, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Qinglu Zeng
- Department of Ocean Science, The Hong Kong University of Science and Technology, Hong Kong, China; HKUST Shenzhen-Hong Kong Collaborative Innovation Research Institute, Shenzhen, China; Center for Ocean Research in Hong Kong and Macau, The Hong Kong University of Science and Technology, Hong Kong, China.
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2
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Ong DRY, Gutiérrez-Rodríguez A, Garczarek L, Marie D, Lopes dos Santos A. Nested PCR Approach for petB Gene Metabarcoding of Marine Synechococcus Populations. Microbiol Spectr 2023; 11:e0408622. [PMID: 36877067 PMCID: PMC10100653 DOI: 10.1128/spectrum.04086-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 01/30/2023] [Indexed: 03/07/2023] Open
Abstract
The molecular diversity of marine picocyanobacterial populations, an important component of phytoplankton communities, is better characterized using high-resolution marker genes than the 16S rRNA gene as they have greater sequence divergence to differentiate between closely related picocyanobacteria groups. Although specific ribosomal primers have been developed, another general disadvantage of bacterial ribosome-based diversity analyses is the variable number of rRNA gene copies. To overcome these issues, the single-copy petB gene, encoding the cytochrome b6 subunit of the cytochrome b6f complex, has been used as a high-resolution marker gene to characterize Synechococcus diversity. We have designed new primers targeting the petB gene and proposed a nested PCR method (termed Ong_2022) for metabarcoding of marine Synechococcus populations obtained by flow cytometry cell sorting. We evaluated the specificity and sensitivity of Ong_2022 against the standard amplification protocol (termed Mazard_2012) using filtered seawater samples. The Ong_2022 approach was also tested on flow cytometry-sorted Synechococcus populations. Samples (filtered and sorted) were obtained in the Southwest Pacific Ocean, from subtropical (ST) and subantarctic (SA) water masses. The two PCR approaches using filtered samples recovered the same dominant subclades, Ia, Ib, IVa, and IVb, with small differences in relative abundance across the distinct samples. For example, subclade IVa was dominant in ST samples with the Mazard_2012 approach, while the same samples processed with Ong_2022 showed similar contributions of subclades IVa and Ib to the total community. The Ong_2022 approach generally captured a higher genetic diversity of Synechococcus subcluster 5.1 than the Mazard_2012 approach while having a lower proportion of incorrectly assigned amplicon sequence variants (ASVs). All flow cytometry-sorted Synechococcus samples could be amplified only by our nested approach. The taxonomic diversity obtained with our primers on both sample types was in agreement with the clade distribution observed by previous studies that applied other marker genes or PCR-free metagenomic approaches under similar environmental conditions. IMPORTANCE The petB gene has been proposed as a high-resolution marker gene to access the diversity of marine Synechococcus populations. A systematic metabarcoding approach based on the petB gene would improve the characterization/assessment of the Synechococcus community structure in marine planktonic ecosystems. We have designed and tested specific primers to be applied in a nested PCR protocol (Ong_2022) for metabarcoding the petB gene. The Ong_2022 protocol can be applied to samples with low DNA content, such as those obtained by flow cytometry cell sorting, allowing the simultaneous assessment of the genetic diversity of Synechococcus populations and cellular properties and activities (e.g., nutrient cell ratios or carbon uptake rates). Our approach will allow future studies using flow cytometry to investigate the link between ecological traits and taxonomic diversity of marine Synechococcus.
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Affiliation(s)
- Denise Rui Ying Ong
- Asian School of the Environment, Nanyang Technological University, Singapore
| | | | - Laurence Garczarek
- Sorbonne Université, CNRS, UMR 7144 (AD2M), Station Biologique de Roscoff, Roscoff, France
| | - Dominique Marie
- Sorbonne Université, CNRS, UMR 7144 (AD2M), Station Biologique de Roscoff, Roscoff, France
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Muñoz-Marín MDC, Duhamel S, Björkman KM, Magasin JD, Díez J, Karl DM, García-Fernández JM. Differential Timing for Glucose Assimilation in Prochlorococcus and Coexistent Microbial Populations in the North Pacific Subtropical Gyre. Microbiol Spectr 2022; 10:e0246622. [PMID: 36098532 PMCID: PMC9602893 DOI: 10.1128/spectrum.02466-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 08/22/2022] [Indexed: 01/04/2023] Open
Abstract
The marine cyanobacterium Prochlorococcus can utilize glucose as a source of carbon. However, the relative importance of inorganic and organic carbon assimilation and the timing of glucose assimilation are still poorly understood in these numerically dominant cyanobacteria. Here, we investigated whole microbial community and group-specific primary production and glucose assimilation using incubations with radioisotopes combined with flow cytometry cell sorting. We also studied changes in the microbial community structure in response to glucose enrichments and analyzed the transcription of Prochlorocccus genes involved in carbon metabolism and photosynthesis. Our results showed a diel variation for glucose assimilation in Prochlorococcus, with maximum assimilation at midday and minimum at midnight (~2-fold change), which was different from that of the total microbial community. This suggests that the timing in glucose assimilation in Prochlorococcus is coupled to photosynthetic light reactions producing energy, it being more convenient for Prochlorococcus to show maximum glucose uptake precisely when the rest of microbial populations have their minimum glucose uptake. Many transcriptional responses to glucose enrichment occurred after 12- and 24-h periods, but community composition did not change. High-light Prochlorococcus strains were the most impacted by glucose addition, with transcript-level increases observed for genes in pathways for glucose metabolism, such as the pentose phosphate pathway, the Entner-Doudoroff pathway, glycolysis, respiration, and glucose transport. While Prochlorococcus C assimilation from glucose represented less than 0.1% of the bacterium's photosynthetic C fixation, increased assimilation during the day and glcH gene upregulation upon glucose enrichment indicate an important role of mixotrophic C assimilation by natural populations of Prochlorococcus. IMPORTANCE Several studies have demonstrated that Prochlorococcus, the most abundant photosynthetic organism on Earth, can assimilate organic molecules, such as amino acids, amino sugars, ATP, phosphonates, and dimethylsulfoniopropionate. This autotroph can also assimilate small amounts of glucose, supporting the hypothesis that Prochlorococcus is mixotrophic. Our results show, for the first time, a diel variability in glucose assimilation by natural populations of Prochlorococcus with maximum assimilation during midday. Based on our previous results, this indicates that Prochlorococcus could maximize glucose uptake by using ATP made during the light reactions of photosynthesis. Furthermore, Prochlorococcus showed a different timing of glucose assimilation from the total population, which may offer considerable fitness advantages over competitors "temporal niches." Finally, we observed transcriptional changes in some of the genes involved in carbon metabolism, suggesting that Prochlorococcus can use both pathways previously proposed in cyanobacteria to metabolize glucose.
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Affiliation(s)
- María del Carmen Muñoz-Marín
- Departamento de Bioquímica y Biología Molecular, Campus de Excelencia Internacional Agroalimentario, Universidad de Córdoba, Córdoba, Spain
| | - Solange Duhamel
- Lamont-Doherty Earth Observatory of Columbia University, Division of Biology and Paleo Environment, Palisades, New York, USA
| | - Karin M. Björkman
- Daniel K. Inouye Center for Microbial Oceanography: Research and Education (C-MORE), University of Hawaii at Manoa, C-MORE Hale, Honolulu, Hawaii, USA
| | - Jonathan D. Magasin
- Ocean Sciences Department, University of California, Santa Cruz, California, USA
| | - Jesús Díez
- Departamento de Bioquímica y Biología Molecular, Campus de Excelencia Internacional Agroalimentario, Universidad de Córdoba, Córdoba, Spain
| | - David M. Karl
- Daniel K. Inouye Center for Microbial Oceanography: Research and Education (C-MORE), University of Hawaii at Manoa, C-MORE Hale, Honolulu, Hawaii, USA
| | - José M. García-Fernández
- Departamento de Bioquímica y Biología Molecular, Campus de Excelencia Internacional Agroalimentario, Universidad de Córdoba, Córdoba, Spain
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Selão TT. Exploring cyanobacterial diversity for sustainable biotechnology. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:3057-3071. [PMID: 35467729 DOI: 10.1093/jxb/erac053] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 04/22/2022] [Indexed: 06/14/2023]
Abstract
Cyanobacteria are an evolutionarily ancient and diverse group of microorganisms. Their genetic diversity has
allowed them to occupy and play vital roles in a wide range of ecological niches, from desert soil crusts to tropical oceans. Owing to bioprospecting efforts and the development of new platform technologies enabling their study and manipulation, our knowledge of cyanobacterial metabolism is rapidly expanding. This review explores our current understanding of the genetic and metabolic features of cyanobacteria, from the more established cyanobacterial model strains to the newly isolated/described species, particularly the fast-growing, highly productive, and genetically amenable strains, as promising chassis for renewable biotechnology. It also discusses emerging technologies for their study and manipulation, enabling researchers to harness the astounding diversity of the cyanobacterial genomic and metabolic treasure trove towards the establishment of a sustainable bioeconomy.
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Affiliation(s)
- Tiago Toscano Selão
- Department of Chemical and Environmental Engineering, University of Nottingham, University Park Campus, Nottingham NG7 2RD, UK
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5
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Accumulation of ambient phosphate into the periplasm of marine bacteria is proton motive force dependent. Nat Commun 2020; 11:2642. [PMID: 32457313 PMCID: PMC7250820 DOI: 10.1038/s41467-020-16428-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 04/24/2020] [Indexed: 12/20/2022] Open
Abstract
Bacteria acquire phosphate (Pi) by maintaining a periplasmic concentration below environmental levels. We recently described an extracellular Pi buffer which appears to counteract the gradient required for Pi diffusion. Here, we demonstrate that various treatments to outer membrane (OM) constituents do not affect the buffered Pi because bacteria accumulate Pi in the periplasm, from which it can be removed hypo-osmotically. The periplasmic Pi can be gradually imported into the cytoplasm by ATP-powered transport, however, the proton motive force (PMF) is not required to keep Pi in the periplasm. In contrast, the accumulation of Pi into the periplasm across the OM is PMF-dependent and can be enhanced by light energy. Because the conventional mechanism of Pi-specific transport cannot explain Pi accumulation in the periplasm we propose that periplasmic Pi anions pair with chemiosmotic cations of the PMF and millions of accumulated Pi pairs could influence the periplasmic osmolarity of marine bacteria. The ubiquitous oceanic bacteria harbour an external phosphate buffer for modulating phosphate (Pi) uptake. Here, using both oceanic SAR11, Prochlorococcus and Synechococcus strains as a model, the authors show that the Pi buffer accumulation in the periplasm is proton motive force-dependent and can be enhanced by light energy.
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Li J, Gu X, Gui Y. Prokaryotic Diversity and Composition of Sediments From Prydz Bay, the Antarctic Peninsula Region, and the Ross Sea, Southern Ocean. Front Microbiol 2020; 11:783. [PMID: 32411115 PMCID: PMC7198716 DOI: 10.3389/fmicb.2020.00783] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 04/01/2020] [Indexed: 11/13/2022] Open
Abstract
The V3–V4 hypervariable regions of the 16S ribosomal RNA gene were analyzed to assess prokaryotic diversity and community compositions within 19 surface sediment samples collected from three different regions (depth: 250–3,548 m) of Prydz Bay, the Antarctic Peninsula region, and the Ross Sea. In our results, we characterized 1,079,709 clean tag sequences representing 43,227 operational taxonomic units (OTUs, 97% similarity). The prokaryotic community distribution exhibited obvious geographical differences, and the sequences formed three distinct clusters according to the samples’ origins. In general, the biodiversity of Prydz Bay was higher than those of the Antarctic Peninsula region and the Ross Sea, and there were similar prokaryotic communities in different geographic locations. The most dominant clades in the prokaryotic communities were Proteobacteria, Bacteroidetes, Thaumarchaeota, Oxyphotobacteria, Deinococcus-Thermus, Firmicutes, Acidobacteria, Fusobacteria, and Planctomycetes, but unique prokaryotic community compositions were found in each of the sampling regions. Our results also demonstrated that the prokaryotic diversity and community distribution were mainly influenced by geographical and physicochemical factors, such as Zn, V, Na, K, water depth, and especially geographical distance (longitude variation of sample location) and Ba ion content. Moreover, geochemical factors such as nutrient contents (TC, P, and Ca) also played important roles in prokaryotic diversity and community distribution. This represents the first report that Ba ion content has an obvious effect on prokaryotic diversity and community distribution in Southern Ocean sediments.
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Affiliation(s)
- Jiang Li
- Marine Bioresource and Environment Research Center, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, China.,Ministry of Natural Resources (MNR) Key Lab for Science & Technology of Marine Ecosystems, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, China
| | - Xiaoqian Gu
- Marine Bioresource and Environment Research Center, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, China.,Ministry of Natural Resources (MNR) Key Lab for Science & Technology of Marine Ecosystems, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, China
| | - Yuanyuan Gui
- College of Environmental Science and Engineering Qingdao University, Qingdao, China
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Berthelot H, Duhamel S, L'Helguen S, Maguer JF, Wang S, Cetinić I, Cassar N. NanoSIMS single cell analyses reveal the contrasting nitrogen sources for small phytoplankton. ISME JOURNAL 2018; 13:651-662. [PMID: 30323264 DOI: 10.1038/s41396-018-0285-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Revised: 07/09/2018] [Accepted: 09/08/2018] [Indexed: 12/16/2022]
Abstract
Nitrogen (N) is a limiting nutrient in vast regions of the world's oceans, yet the sources of N available to various phytoplankton groups remain poorly understood. In this study, we investigated inorganic carbon (C) fixation rates and nitrate (NO3-), ammonium (NH4+) and urea uptake rates at the single cell level in photosynthetic pico-eukaryotes (PPE) and the cyanobacteria Prochlorococcus and Synechococcus. To that end, we used dual 15N and 13C-labeled incubation assays coupled to flow cytometry cell sorting and nanoSIMS analysis on samples collected in the North Pacific Subtropical Gyre (NPSG) and in the California Current System (CCS). Based on these analyses, we found that photosynthetic growth rates (based on C fixation) of PPE were higher in the CCS than in the NSPG, while the opposite was observed for Prochlorococcus. Reduced forms of N (NH4+ and urea) accounted for the majority of N acquisition for all the groups studied. NO3- represented a reduced fraction of total N uptake in all groups but was higher in PPE (17.4 ± 11.2% on average) than in Prochlorococcus and Synechococcus (4.5 ± 6.5 and 2.9 ± 2.1% on average, respectively). This may in part explain the contrasting biogeography of these picoplankton groups. Moreover, single cell analyses reveal that cell-to-cell heterogeneity within picoplankton groups was significantly greater for NO3- uptake than for C fixation and NH4+ uptake. We hypothesize that cellular heterogeneity in NO3- uptake within groups facilitates adaptation to the fluctuating availability of NO3- in the environment.
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Affiliation(s)
- Hugo Berthelot
- Laboratoire des Sciences de l'Environnement Marin (LEMAR), UMR 6539 UBO/CNRS/IRD/IFREMER, Institut Universitaire Européen de la Mer (IUEM), Brest, France.
| | - Solange Duhamel
- Division of Biology and Paleo Environment, Lamont-Doherty Earth Observatory, PO Box 1000, 61 Route 9W, Palisades, NY, 10964, USA
| | - Stéphane L'Helguen
- Laboratoire des Sciences de l'Environnement Marin (LEMAR), UMR 6539 UBO/CNRS/IRD/IFREMER, Institut Universitaire Européen de la Mer (IUEM), Brest, France
| | - Jean-Francois Maguer
- Laboratoire des Sciences de l'Environnement Marin (LEMAR), UMR 6539 UBO/CNRS/IRD/IFREMER, Institut Universitaire Européen de la Mer (IUEM), Brest, France
| | - Seaver Wang
- Division of Earth and Ocean Sciences, Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
| | - Ivona Cetinić
- NASA Goddard Space Flight Center, Ocean Ecology Laboratory, Code 616, Greenbelt, MD, USA.,GESTAR/Universities Space Research Association, Columbia, MD, USA
| | - Nicolas Cassar
- Laboratoire des Sciences de l'Environnement Marin (LEMAR), UMR 6539 UBO/CNRS/IRD/IFREMER, Institut Universitaire Européen de la Mer (IUEM), Brest, France. .,Division of Earth and Ocean Sciences, Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA.
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Zinser ER. Cross-protection from hydrogen peroxide by helper microbes: the impacts on the cyanobacterium Prochlorococcus and other beneficiaries in marine communities. ENVIRONMENTAL MICROBIOLOGY REPORTS 2018; 10:399-411. [PMID: 29411546 DOI: 10.1111/1758-2229.12625] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 01/25/2018] [Accepted: 01/27/2017] [Indexed: 05/27/2023]
Abstract
Hydrogen peroxide (HOOH) is a reactive oxygen species, derived from molecular oxygen, that is capable of damaging microbial cells. Surprisingly, the HOOH defence systems of some aerobes in the oxygenated marine environments are critically depleted, relative to model aerobes. For instance, the gene encoding catalase is absent in the numerically dominant photosynthetic cyanobacterium, Prochlorococcus. Accordingly, Prochlorococcus is highly susceptible to HOOH when exposed as pure cultures. Pure cultures do not exist in the marine environment, however. Catalase-positive community members can remove HOOH from the seawater medium, thus lowering the threat to Prochlorococcus and any other member that likewise lacks their own catalase. This cross-protection may constitute a loosely defined symbiosis, whereby the catalase-positive helper cells may benefit through the acquisition of nutrients released by the beneficiaries such as Prochlorococcus. Other members of the community that may be helped by the catalase-positive cells may include some lineages of Synechococcus - the sister genus of Prochlorococcus - as well as some lineages of SAR11 and ammonia oxidizing archaea and bacteria. The co-occurrence of catalase-positive and -negative members suggests that cross-protection from HOOH-mediated oxidative stress may play an important role in the construction of the marine microbial community.
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Affiliation(s)
- Erik R Zinser
- Department of Microbiology, University of Tennessee, Knoxville, TN 37996, USA
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Abstract
The role of marine bioaerosols in cloud formation and climate is currently so uncertain that even the sign of the climate forcing is unclear. Marine aerosols form through direct emissions and through the conversion of gas-phase emissions to aerosols in the atmosphere. The composition and size of aerosols determine how effective they are in catalyzing the formation of water droplets and ice crystals in clouds by acting as cloud condensation nuclei and ice nucleating particles, respectively. Marine organic aerosols may be sourced both from recent regional phytoplankton blooms that add labile organic matter to the surface ocean and from long-term global processes, such as the upwelling of old refractory dissolved organic matter from the deep ocean. Understanding the formation of marine aerosols and their propensity to catalyze cloud formation processes are challenges that must be addressed given the major uncertainties associated with aerosols in climate models.
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Affiliation(s)
- Sarah D Brooks
- Department of Atmospheric Sciences, Texas A&M University, College Station, Texas 77843, USA;
| | - Daniel C O Thornton
- Department of Oceanography, Texas A&M University, College Station, Texas 77843, USA;
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10
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Liang Y, Zhang Y, Wang N, Luo T, Zhang Y, Rivkin RB. Estimating Primary Production of Picophytoplankton Using the Carbon-Based Ocean Productivity Model: A Preliminary Study. Front Microbiol 2017; 8:1926. [PMID: 29051755 PMCID: PMC5633608 DOI: 10.3389/fmicb.2017.01926] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 09/21/2017] [Indexed: 11/13/2022] Open
Abstract
Picophytoplankton are acknowledged to contribute significantly to primary production (PP) in the ocean while now the method to measure PP of picophytoplankton (PPPico) at large scales is not yet well established. Although the traditional 14C method and new technologies based on the use of stable isotopes (e.g., 13C) can be employed to accurately measure in situ PPPico, the time-consuming and labor-intensive shortage of these methods constrain their application in a survey on large spatiotemporal scales. To overcome this shortage, a modified carbon-based ocean productivity model (CbPM) is proposed for estimating the PPPico whose principle is based on the group-specific abundance, cellular carbon conversion factor (CCF), and temperature-derived growth rate of picophytoplankton. Comparative analysis showed that the estimated PPPico using CbPM method is significantly and positively related (r2 = 0.53, P < 0.001, n = 171) to the measured 14C uptake. This significant relationship suggests that CbPM has the potential to estimate the PPPico over large spatial and temporal scales. Currently this model application may be limited by the use of invariant cellular CCF and the relatively small data sets to validate the model which may introduce some uncertainties and biases. Model performance will be improved by the use of variable conversion factors and the larger data sets representing diverse growth conditions. Finally, we apply the CbPM-based model on the collected data during four cruises in the Bohai Sea in 2005. Model-estimated PPPico ranged from 0.1 to 11.9, 29.9 to 432.8, 5.5 to 214.9, and 2.4 to 65.8 mg C m-2 d-1 during March, June, September, and December, respectively. This study shed light on the estimation of global PPPico using carbon-based production model.
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Affiliation(s)
- Yantao Liang
- Research Center for Marine Biology and Carbon Sequestration, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,Institute of Marine Microbes and Ecospheres, State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
| | - Yongyu Zhang
- Research Center for Marine Biology and Carbon Sequestration, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Nannan Wang
- Institute of Marine Microbes and Ecospheres, State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
| | - Tingwei Luo
- Institute of Marine Microbes and Ecospheres, State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
| | - Yao Zhang
- Institute of Marine Microbes and Ecospheres, State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
| | - Richard B Rivkin
- Department of Ocean Sciences, Memorial University of Newfoundland, St. John's, NL, Canada
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11
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Grossowicz M, Marques GM, van Voorn GA. A dynamic energy budget (DEB) model to describe population dynamics of the marine cyanobacterium Prochlorococcus marinus. Ecol Modell 2017. [DOI: 10.1016/j.ecolmodel.2017.06.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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12
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Alvarenga DO, Fiore MF, Varani AM. A Metagenomic Approach to Cyanobacterial Genomics. Front Microbiol 2017; 8:809. [PMID: 28536564 PMCID: PMC5422444 DOI: 10.3389/fmicb.2017.00809] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 04/20/2017] [Indexed: 01/08/2023] Open
Abstract
Cyanobacteria, or oxyphotobacteria, are primary producers that establish ecological interactions with a wide variety of organisms. Although their associations with eukaryotes have received most attention, interactions with bacterial and archaeal symbionts have also been occurring for billions of years. Due to these associations, obtaining axenic cultures of cyanobacteria is usually difficult, and most isolation efforts result in unicyanobacterial cultures containing a number of associated microbes, hence composing a microbial consortium. With rising numbers of cyanobacterial blooms due to climate change, demand for genomic evaluations of these microorganisms is increasing. However, standard genomic techniques call for the sequencing of axenic cultures, an approach that not only adds months or even years for culture purification, but also appears to be impossible for some cyanobacteria, which is reflected in the relatively low number of publicly available genomic sequences of this phylum. Under the framework of metagenomics, on the other hand, cumbersome techniques for achieving axenic growth can be circumvented and individual genomes can be successfully obtained from microbial consortia. This review focuses on approaches for the genomic and metagenomic assessment of non-axenic cyanobacterial cultures that bypass requirements for axenity. These methods enable researchers to achieve faster and less costly genomic characterizations of cyanobacterial strains and raise additional information about their associated microorganisms. While non-axenic cultures may have been previously frowned upon in cyanobacteriology, latest advancements in metagenomics have provided new possibilities for in vitro studies of oxyphotobacteria, renewing the value of microbial consortia as a reliable and functional resource for the rapid assessment of bloom-forming cyanobacteria.
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Affiliation(s)
- Danillo O. Alvarenga
- Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista (UNESP)Jaboticabal, Brazil
- Centro de Energia Nuclear na Agricultura, Universidade de São Paulo (USP)Piracicaba, Brazil
| | - Marli F. Fiore
- Centro de Energia Nuclear na Agricultura, Universidade de São Paulo (USP)Piracicaba, Brazil
| | - Alessandro M. Varani
- Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista (UNESP)Jaboticabal, Brazil
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13
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Braakman R, Follows MJ, Chisholm SW. Metabolic evolution and the self-organization of ecosystems. Proc Natl Acad Sci U S A 2017; 114:E3091-E3100. [PMID: 28348231 PMCID: PMC5393222 DOI: 10.1073/pnas.1619573114] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Metabolism mediates the flow of matter and energy through the biosphere. We examined how metabolic evolution shapes ecosystems by reconstructing it in the globally abundant oceanic phytoplankter Prochlorococcus To understand what drove observed evolutionary patterns, we interpreted them in the context of its population dynamics, growth rate, and light adaptation, and the size and macromolecular and elemental composition of cells. This multilevel view suggests that, over the course of evolution, there was a steady increase in Prochlorococcus' metabolic rate and excretion of organic carbon. We derived a mathematical framework that suggests these adaptations lower the minimal subsistence nutrient concentration of cells, which results in a drawdown of nutrients in oceanic surface waters. This, in turn, increases total ecosystem biomass and promotes the coevolution of all cells in the ecosystem. Additional reconstructions suggest that Prochlorococcus and the dominant cooccurring heterotrophic bacterium SAR11 form a coevolved mutualism that maximizes their collective metabolic rate by recycling organic carbon through complementary excretion and uptake pathways. Moreover, the metabolic codependencies of Prochlorococcus and SAR11 are highly similar to those of chloroplasts and mitochondria within plant cells. These observations lead us to propose a general theory relating metabolic evolution to the self-amplification and self-organization of the biosphere. We discuss the implications of this framework for the evolution of Earth's biogeochemical cycles and the rise of atmospheric oxygen.
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Affiliation(s)
- Rogier Braakman
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139;
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Michael J Follows
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Sallie W Chisholm
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139;
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
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Helliwell KE, Lawrence AD, Holzer A, Kudahl UJ, Sasso S, Kräutler B, Scanlan DJ, Warren MJ, Smith AG. Cyanobacteria and Eukaryotic Algae Use Different Chemical Variants of Vitamin B12. Curr Biol 2016; 26:999-1008. [PMID: 27040778 PMCID: PMC4850488 DOI: 10.1016/j.cub.2016.02.041] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 02/15/2016] [Accepted: 02/17/2016] [Indexed: 01/04/2023]
Abstract
Eukaryotic microalgae and prokaryotic cyanobacteria are the major components of the phytoplankton. Determining factors that govern growth of these primary producers, and how they interact, is therefore essential to understanding aquatic ecosystem productivity. Over half of microalgal species representing marine and freshwater habitats require for growth the corrinoid cofactor B12, which is synthesized de novo only by certain prokaryotes, including the majority of cyanobacteria. There are several chemical variants of B12, which are not necessarily functionally interchangeable. Cobalamin, the form bioavailable to humans, has as its lower axial ligand 5,6-dimethylbenzimidazole (DMB). Here, we show that the abundant marine cyanobacterium Synechococcus synthesizes only pseudocobalamin, in which the lower axial ligand is adenine. Moreover, bioinformatic searches of over 100 sequenced cyanobacterial genomes for B12 biosynthesis genes, including those involved in nucleotide loop assembly, suggest this is the form synthesized by cyanobacteria more broadly. We further demonstrate that pseudocobalamin is several orders of magnitude less bioavailable than cobalamin to several B12-dependent microalgae representing diverse lineages. This indicates that the two major phytoplankton groups use a different B12 currency. However, in an intriguing twist, some microalgal species can use pseudocobalamin if DMB is provided, suggesting that they are able to remodel the cofactor, whereas Synechococcus cannot. This species-specific attribute implicates algal remodelers as novel and keystone players of the B12 cycle, transforming our perception of the dynamics and complexity of the flux of this nutrient in aquatic ecosystems. Dominant marine cyanobacteria synthesize only pseudocobalamin Pseudocobalamin is orders of magnitude less bioavailable to eukaryotic algae Certain algae can remodel pseudocobalamin to a bioavailable form This implies a complex B12 cycle between microbes in the photic zone
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Affiliation(s)
| | | | - Andre Holzer
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK; Institute of Pharmacy and Molecular Biotechnology, Ruprecht-Karls University Heidelberg, Im Neuenheimer Feld 364, 69120 Heidelberg, Germany
| | - Ulrich Johan Kudahl
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK
| | - Severin Sasso
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK
| | - Bernhard Kräutler
- Institute of Organic Chemistry and Centre of Molecular Biosciences, University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | | | | | - Alison Gail Smith
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK.
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15
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Björkman KM, Church MJ, Doggett JK, Karl DM. Differential Assimilation of Inorganic Carbon and Leucine by Prochlorococcus in the Oligotrophic North Pacific Subtropical Gyre. Front Microbiol 2015; 6:1401. [PMID: 26733953 PMCID: PMC4681814 DOI: 10.3389/fmicb.2015.01401] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 11/24/2015] [Indexed: 11/17/2022] Open
Abstract
The light effect on photoheterotrophic processes in Prochlorococcus, and primary and bacterial productivity in the oligotrophic North Pacific Subtropical Gyre was investigated using 14C-bicarbonate and 3H-leucine. Light and dark incubation experiments were conducted in situ throughout the euphotic zone (0–175 m) on nine expeditions to Station ALOHA over a 3-year period. Photosynthetrons were also used to elucidate rate responses in leucine and inorganic carbon assimilation as a function of light intensity. Taxonomic group and cell-specific rates were assessed using flow cytometric sorting. The light:dark assimilation rate ratios of leucine in the top 150 m were ∼7:1 for Prochlorococcus, whereas the light:dark ratios for the non-pigmented bacteria (NPB) were not significant different from 1:1. Prochlorococcus assimilated leucine in the dark at per cell rates similar to the NPB, with a contribution to the total community bacterial production, integrated over the euphotic zone, of approximately 20% in the dark and 60% in the light. Depth-resolved primary productivity and leucine incorporation showed that the ratio of Prochlorococcus leucine:primary production peaked at 100 m then declined steeply below the deep chlorophyll maximum (DCM). The photosynthetron experiments revealed that, for Prochlorococcus at the DCM, the saturating irradiance (Ek) for leucine incorporation was reached at approximately half the light intensity required for light saturation of 14C-bicarbonate assimilation. Additionally, high and low red fluorescing Prochlorococcus populations (HRF and LRF), co-occurring at the DCM, had similar Ek values for their respective substrates, however, maximum assimilation rates, for both leucine and inorganic carbon, were two times greater for HRF cells. Our results show that Prochlorococcus contributes significantly to bacterial production estimates using 3H-leucine, whether or not the incubations are conducted in the dark or light, and this should be considered when making assessments of bacterial production in marine environments where Prochlorococcus is present. Furthermore, Prochlorococcus primary productivity showed rate to light-flux patterns that were different from its light enhanced leucine incorporation. This decoupling from autotrophic growth may indicate a separate light stimulated mechanism for leucine acquisition.
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Affiliation(s)
- Karin M Björkman
- Department of Oceanography and Daniel K. Inouye Center for Microbial Ecology: Research and Education, University of Hawaii, Honolulu HI, USA
| | - Matthew J Church
- Department of Oceanography and Daniel K. Inouye Center for Microbial Ecology: Research and Education, University of Hawaii, Honolulu HI, USA
| | - Joseph K Doggett
- Department of Oceanography and Daniel K. Inouye Center for Microbial Ecology: Research and Education, University of Hawaii, Honolulu HI, USA
| | - David M Karl
- Department of Oceanography and Daniel K. Inouye Center for Microbial Ecology: Research and Education, University of Hawaii, Honolulu HI, USA
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Rees A, Robinson C, Smyth T, Aiken J, Nightingale P, Zubkov M. 20 Years of the Atlantic Meridional Transect-AMT. ACTA ACUST UNITED AC 2015. [DOI: 10.1002/lob.10069] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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17
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Zubkov MV, Martin AP, Hartmann M, Grob C, Scanlan DJ. Dominant oceanic bacteria secure phosphate using a large extracellular buffer. Nat Commun 2015. [PMID: 26198420 PMCID: PMC4525184 DOI: 10.1038/ncomms8878] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
The ubiquitous SAR11 and Prochlorococcus bacteria manage to maintain a sufficient supply of phosphate in phosphate-poor surface waters of the North Atlantic subtropical gyre. Furthermore, it seems that their phosphate uptake may counter-intuitively be lower in more productive tropical waters, as if their cellular demand for phosphate decreases there. By flow sorting 33P-phosphate-pulsed 32P-phosphate-chased cells, we demonstrate that both Prochlorococcus and SAR11 cells exploit an extracellular buffer of labile phosphate up to 5–40 times larger than the amount of phosphate required to replicate their chromosomes. Mathematical modelling is shown to support this conclusion. The fuller the buffer the slower the cellular uptake of phosphate, to the point that in phosphate-replete tropical waters, cells can saturate their buffer and their phosphate uptake becomes marginal. Hence, buffer stocking is a generic, growth-securing adaptation for SAR11 and Prochlorococcus bacteria, which lack internal reserves to reduce their dependency on bioavailable ambient phosphate. Oceanic SAR11 Alphaproteobacteria and Prochlorococcus cyanobacteria are abundant in phosphate-poor regions, despite it being vital for growth. Here, Zubkov et al. show these bacterioplankton exploit an extracellular buffer of labile phosphate to reduce their dependency on bioavailable ambient phosphate.
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Affiliation(s)
- Mikhail V Zubkov
- National Oceanography Centre, Ocean Biogeochemistry &Ecosystems Research Group, European Way, Southampton SO14 3ZH, UK
| | - Adrian P Martin
- National Oceanography Centre, Ocean Biogeochemistry &Ecosystems Research Group, European Way, Southampton SO14 3ZH, UK
| | - Manuela Hartmann
- National Oceanography Centre, Ocean Biogeochemistry &Ecosystems Research Group, European Way, Southampton SO14 3ZH, UK
| | - Carolina Grob
- School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
| | - David J Scanlan
- School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
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Grob C, Jardillier L, Hartmann M, Ostrowski M, Zubkov MV, Scanlan DJ. Cell-specific CO2 fixation rates of two distinct groups of plastidic protists in the Atlantic Ocean remain unchanged after nutrient addition. ENVIRONMENTAL MICROBIOLOGY REPORTS 2015; 7:211-218. [PMID: 25345650 DOI: 10.1111/1758-2229.12228] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 09/18/2014] [Accepted: 09/22/2014] [Indexed: 06/04/2023]
Abstract
To assess the role of open-ocean ecosystems in global CO2 fixation, we investigated how picophytoplankton, which dominate primary production, responded to episodic increases in nutrient availability. Previous experiments have shown nitrogen alone, or in combination with phosphorus or iron, to be the proximate limiting nutrient(s) for total phytoplankton grown over several days. Much less is known about how nutrient upshift affects picophytoplankton CO2 fixation over the duration of the light period. To address this issue, we performed a series of small volume (8-60 ml) - short term (10-11 h) nutrient addition experiments in different regions of the Atlantic Ocean using NH4 Cl, FeCl3 , K medium, dust and nutrient-rich water from 300 m depth. We found no significant nutrient stimulation of group-specific CO2 fixation rates of two taxonomically and size-distinct groups of plastidic protists. The above was true regardless of the region sampled or nutrient added, suggesting that this is a generic phenomenon. Our findings show that at least in the short term (i.e. daylight period), nutrient availability does not limit CO2 fixation by the smallest plastidic protists, while their taxonomic composition does not determine their response to nutrient addition.
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Affiliation(s)
- Carolina Grob
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
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