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Muñoz-Marín MDC, Magasin JD, Zehr JP. Open ocean and coastal strains of the N2-fixing cyanobacterium UCYN-A have distinct transcriptomes. PLoS One 2023; 18:e0272674. [PMID: 37130101 PMCID: PMC10153697 DOI: 10.1371/journal.pone.0272674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Accepted: 02/18/2023] [Indexed: 05/03/2023] Open
Abstract
Decades of research on marine N2 fixation focused on Trichodesmium, which are generally free-living cyanobacteria, but in recent years the endosymbiotic cyanobacterium Candidatus Atelocyanobacterium thalassa (UCYN-A) has received increasing attention. However, few studies have shed light on the influence of the host versus the habitat on UCYN-A N2 fixation and overall metabolism. Here we compared transcriptomes from natural populations of UCYN-A from oligotrophic open-ocean versus nutrient-rich coastal waters, using a microarray that targets the full genomes of UCYN-A1 and UCYN-A2 and known genes for UCYN-A3. We found that UCYN-A2, usually regarded as adapted to coastal environments, was transcriptionally very active in the open ocean and appeared to be less impacted by habitat change than UCYN-A1. Moreover, for genes with 24 h periodic expression we observed strong but inverse correlations among UCYN-A1, A2, and A3 to oxygen and chlorophyll, which suggests distinct host-symbiont relationships. Across habitats and sublineages, genes for N2 fixation and energy production had high transcript levels, and, intriguingly, were among the minority of genes that kept the same schedule of diel expression. This might indicate different regulatory mechanisms for genes that are critical to the symbiosis for the exchange of nitrogen for carbon from the host. Our results underscore the importance of N2 fixation in UCYN-A symbioses across habitats, with consequences for community interactions and global biogeochemical cycles.
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Affiliation(s)
- María Del Carmen Muñoz-Marín
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, California, United States of America
- Departamento de Bioquímica y Biología Molecular, Campus de Excelencia Internacional Agroalimentario, Universidad de Córdoba, Córdoba, Spain
| | - Jonathan D Magasin
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Jonathan P Zehr
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, California, United States of America
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2
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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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3
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Kim S, Park S, Choi TG, Kim SS. Role of Short Chain Fatty Acids in Epilepsy and Potential Benefits of Probiotics and Prebiotics: Targeting “Health” of Epileptic Patients. Nutrients 2022; 14:nu14142982. [PMID: 35889939 PMCID: PMC9322917 DOI: 10.3390/nu14142982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/17/2022] [Accepted: 07/19/2022] [Indexed: 11/16/2022] Open
Abstract
The WHO’s definition of health transcends the mere absence of disease, emphasizing physical, mental, and social well-being. As this perspective is being increasingly applied to the management of chronic diseases, research on gut microbiota (GM) is surging, with a focus on its potential for persistent and noninvasive dietary therapeutics. In patients with epilepsy (PWE), a chronic lack of seizure control along with often neglected psychiatric comorbidities greatly disrupt the quality of life. Evidence shows that GM-derived short chain fatty acids (SCFAs) may impact seizure susceptibility through modulating (1) excitatory/inhibitory neurotransmitters, (2) oxidative stress and neuroinflammation, and (3) psychosocial stress. These functions are also connected to shared pathologies of epilepsy and its two most common psychiatric consequences: depression and anxiety. As the enhancement of SCFA production is enabled through direct administration, as well as probiotics and prebiotics, related dietary treatments may exert antiseizure effects. This paper explores the potential roles of SCFAs in the context of seizure control and its mental comorbidities, while analyzing existing studies on the effects of pro/prebiotics on epilepsy. Based on currently available data, this study aims to interpret the role of SCFAs in epileptic treatment, extending beyond the absence of seizures to target the health of PWE.
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Affiliation(s)
- Soomin Kim
- Department of Preliminary Medicine, School of Medicine, Kyung Hee University, Seoul 02447, Korea;
| | - Siyeon Park
- School of Pharmacy, Massachusetts College of Pharmacy and Health Sciences, Boston, MA 02115, USA;
| | - Tae Gyu Choi
- Department of Biochemistry and Molecular Biology, School of Medicine, Kyung Hee University, Seoul 02447, Korea
- Biomedical Science Institute, Kyung Hee University, Seoul 02447, Korea
- Correspondence: (T.G.C.); (S.S.K.); Tel.: +82-2-961-0287 (T.G.C.); +82-2-961-0524 (S.S.K.)
| | - Sung Soo Kim
- Department of Biochemistry and Molecular Biology, School of Medicine, Kyung Hee University, Seoul 02447, Korea
- Biomedical Science Institute, Kyung Hee University, Seoul 02447, Korea
- Correspondence: (T.G.C.); (S.S.K.); Tel.: +82-2-961-0287 (T.G.C.); +82-2-961-0524 (S.S.K.)
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Rose A, Padovan A, Christian K, van de Kamp J, Kaestli M, Tsoukalis S, Bodrossy L, Gibb K. The Diversity of Nitrogen-Cycling Microbial Genes in a Waste Stabilization Pond Reveals Changes over Space and Time that Is Uncoupled to Changing Nitrogen Chemistry. MICROBIAL ECOLOGY 2021; 81:1029-1041. [PMID: 33170351 PMCID: PMC8062326 DOI: 10.1007/s00248-020-01639-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 11/04/2020] [Indexed: 05/26/2023]
Abstract
Nitrogen removal is an important process for wastewater ponds prior to effluent release. Bacteria and archaea can drive nitrogen removal if they possess the genes required to metabolize nitrogen. In the tropical savanna of northern Australia, we identified the previously unresolved microbial communities responsible for nitrogen cycling in a multi-pond wastewater stabilization system by measuring genomic DNA and cDNA for the following: nifH (nitrogen fixation); nosZ (denitrification); hzsA (anammox); archaeal AamoA and bacterial BamoA (ammonia oxidation); nxrB (nitrite oxidation); and nrfA (dissimilatory NO3 reduction to NH3). By collecting 160 DNA and 40 cDNA wastewater samples and measuring nitrogen (N)-cycling genes using a functional gene array, we found that genes from all steps of the N cycle were present and, except for nxrB, were also expressed. As expected, N-cycling communities showed daily, seasonal, and yearly shifts. However, contrary to our prediction, probes from most functional groups, excluding nosZ and AamoA, were different between ponds. Further, different genes that perform the same N-cycling role sometimes had different trends over space and time, resulting in only weak correlations between the different functional communities. Although N-cycling communities were correlated with wastewater nitrogen levels and physico-chemistry, the relationship was not strong enough to reliably predict the presence or diversity of N-cycling microbes. The complex and dynamic response of these genes to other functional groups and the changing physico-chemical environment provides insight into why altering wastewater pond conditions can result an abundance of some gene variants while others are lost.
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Affiliation(s)
- A Rose
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory, 0909, Australia.
| | - A Padovan
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory, 0909, Australia
| | - K Christian
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory, 0909, Australia
| | - J van de Kamp
- CSIRO Oceans and Atmosphere, Hobart, Tasmania, 7004, Australia
| | - M Kaestli
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory, 0909, Australia
| | - S Tsoukalis
- PowerWater Corporation, Darwin, Northern Territory, 0820, Australia
| | - L Bodrossy
- CSIRO Oceans and Atmosphere, Hobart, Tasmania, 7004, Australia
| | - K Gibb
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory, 0909, Australia
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5
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Zhou J, Lao YM, Song JT, Jin H, Zhu JM, Cai ZH. Temporal heterogeneity of microbial communities and metabolic activities during a natural algal bloom. WATER RESEARCH 2020; 183:116020. [PMID: 32653764 DOI: 10.1016/j.watres.2020.116020] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 05/31/2020] [Accepted: 06/04/2020] [Indexed: 06/11/2023]
Abstract
Elucidating the interactions between algae and associated microbial communities is critical for understanding the mechanisms that mediate the dynamic of harmful algal blooms (HABs) in marine environment. However, the microbial functional profiles and their biogeochemical potential in HABs process remains elusive, especially during a complete natural HAB cycle. Here, we used pyrosequencing and functional gene array (GeoChip) to investigate microbial community dynamics and metabolic potential during a natural dinoflagellate (Noctiluca scintillans) bloom. The results shown that bacterioplankton exhibited significant temporal heterogeneity over the course of the bloom stages. Microbial succession was co-driven by environmental parameters and biotic interactions. The functional analysis revealed significant variations in microbial metabolism during matter cycling. At bloom onset-stage, metabolic potential associated with iron oxidation and transport was elevated. Carbon fixation and degradation, denitrification, phosphorus acquisition, and sulfur transfer/oxidation were significantly enhanced at the plateau stage. During the decline and terminal stages, oxidative stress, lysis of compounds, and toxin degradation & protease synthesis increased. This work reveal phycosphere microorganisms can enhanced organic C decomposition capacity, altered N assimilation rate and S/P turnover efficiency, and balancing of the Fe budget during HAB process. The ecological linkage analysis has further shown that microbial composition and functional potential were significantly linked to algal blooms occurrence. It suggest that structural variability and functional plasticity of microbial communities influence HAB trajectory.
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Affiliation(s)
- Jin Zhou
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, Guangdong Province, PR China
| | - Yong-Min Lao
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, Guangdong Province, PR China
| | - Jun-Ting Song
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, Guangdong Province, PR China
| | - Hui Jin
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, Guangdong Province, PR China
| | - Jian-Ming Zhu
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, Guangdong Province, PR China
| | - Zhong-Hua Cai
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, Guangdong Province, PR China.
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6
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Shilova IN, Magasin JD, Mills MM, Robidart JC, Turk-Kubo KA, Zehr JP. Phytoplankton transcriptomic and physiological responses to fixed nitrogen in the California current system. PLoS One 2020; 15:e0231771. [PMID: 32310982 PMCID: PMC7170224 DOI: 10.1371/journal.pone.0231771] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 03/31/2020] [Indexed: 11/18/2022] Open
Abstract
Marine phytoplankton are responsible for approximately half of photosynthesis on Earth. However, their ability to drive ocean productivity depends on critical nutrients, especially bioavailable nitrogen (N) which is scarce over vast areas of the ocean. Phytoplankton differ in their preferences for N substrates as well as uptake efficiencies and minimal N requirements relative to other critical nutrients, including iron (Fe) and phosphorus. In this study, we used the MicroTOOLs high-resolution environmental microarray to examine transcriptomic responses of phytoplankton communities in the California Current System (CCS) transition zone to added urea, ammonium, nitrate, and also Fe in the late summer when N depletion is common. Transcript level changes of photosynthetic, carbon fixation, and nutrient stress genes indicated relief of N limitation in many strains of Prochlorococcus, Synechococcus, and eukaryotic phytoplankton. The transcriptomic responses helped explain shifts in physiological and growth responses observed later. All three phytoplankton groups had increased transcript levels of photosynthesis and/or carbon fixation genes in response to all N substrates. However, only Prochlorococcus had decreased transcript levels of N stress genes and grew substantially, specifically after urea and ammonium additions, suggesting that Prochlorococcus outcompeted other community members in these treatments. Diatom transcript levels of carbon fixation genes increased in response to Fe but not to Fe with N which might have favored phytoplankton that were co-limited by N and Fe. Moreover, transcription patterns of closely related strains indicated variability in N utilization, including nitrate utilization by some high-light adapted Prochlorococcus. Finally, up-regulation of urea transporter genes by both Prochlorococcus and Synechococcus in response to filtered deep water suggested a regulatory mechanism other than classic control via the global N regulator NtcA. This study indicated that co-existing phytoplankton strains experience distinct nutrient stresses in the transition zone of the CCS, an understudied region where oligotrophic and coastal communities naturally mix.
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Affiliation(s)
- Irina N. Shilova
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, California, United States of America
- * E-mail: (INS); (JPZ)
| | - Jonathan D. Magasin
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Matthew M. Mills
- Department of Earth System Science, Stanford University, Stanford, California, United States of America
| | - Julie C. Robidart
- Ocean Technology and Engineering, National Oceanography Centre, Southampton, England, United Kingdom
| | - Kendra A. Turk-Kubo
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Jonathan P. Zehr
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, California, United States of America
- * E-mail: (INS); (JPZ)
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7
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The Transcriptional Cycle Is Suited to Daytime N 2 Fixation in the Unicellular Cyanobacterium " Candidatus Atelocyanobacterium thalassa" (UCYN-A). mBio 2019; 10:mBio.02495-18. [PMID: 30602582 PMCID: PMC6315102 DOI: 10.1128/mbio.02495-18] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The symbiotic N2-fixing cyanobacterium UCYN-A, which is closely related to Braarudosphaera bigelowii, and its eukaryotic algal host have been shown to be globally distributed and important in open-ocean N2 fixation. These unique cyanobacteria have reduced metabolic capabilities, even lacking genes for oxygenic photosynthesis and carbon fixation. Cyanobacteria generally use energy from photosynthesis for nitrogen fixation but require mechanisms for avoiding inactivation of the oxygen-sensitive nitrogenase enzyme by ambient oxygen (O2) or the O2 evolved through photosynthesis. This study showed that symbiosis between the N2-fixing cyanobacterium UCYN-A and its eukaryotic algal host has led to adaptation of its daily gene expression pattern in order to enable daytime aerobic N2 fixation, which is likely more energetically efficient than fixing N2 at night, as found in other unicellular marine cyanobacteria. Symbiosis between a marine alga and a N2-fixing cyanobacterium (Cyanobacterium UCYN-A) is geographically widespread in the oceans and is important in the marine N cycle. UCYN-A is uncultivated and is an unusual unicellular cyanobacterium because it lacks many metabolic functions, including oxygenic photosynthesis and carbon fixation, which are typical in cyanobacteria. It is now presumed to be an obligate symbiont of haptophytes closely related to Braarudosphaera bigelowii. N2-fixing cyanobacteria use different strategies to avoid inhibition of N2 fixation by the oxygen evolved in photosynthesis. Most unicellular cyanobacteria temporally separate the two incompatible activities by fixing N2 only at night, but, surprisingly, UCYN-A appears to fix N2 during the day. The goal of this study was to determine how the unicellular UCYN-A strain coordinates N2 fixation and general metabolism compared to other marine cyanobacteria. We found that UCYN-A has distinct daily cycles of many genes despite the fact that it lacks two of the three circadian clock genes found in most cyanobacteria. We also found that the transcription patterns in UCYN-A are more similar to those in marine cyanobacteria that are capable of aerobic N2 fixation in the light, such as Trichodesmium and heterocyst-forming cyanobacteria, than to those in Crocosphaera or Cyanothece species, which are more closely related to unicellular marine cyanobacteria evolutionarily. Our findings suggest that the symbiotic interaction has resulted in a shift of transcriptional regulation to coordinate UCYN-A metabolism with that of the phototrophic eukaryotic host, thus allowing efficient coupling of N2 fixation (by the cyanobacterium) to the energy obtained from photosynthesis (by the eukaryotic unicellular alga) in the light.
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8
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Robidart JC, Magasin JD, Shilova IN, Turk-Kubo KA, Wilson ST, Karl DM, Scholin CA, Zehr JP. Effects of nutrient enrichment on surface microbial community gene expression in the oligotrophic North Pacific Subtropical Gyre. ISME JOURNAL 2018; 13:374-387. [PMID: 30254320 DOI: 10.1038/s41396-018-0280-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 07/26/2018] [Accepted: 08/26/2018] [Indexed: 11/09/2022]
Abstract
Marine microbial communities are critical for biogeochemical cycles and the productivity of ocean ecosystems. Primary productivity in the surface ocean is constrained by nutrients which are supplied, in part, by mixing with deeper water. Little is known about the time scales, frequency, or impact of mixing on microbial communities. We combined in situ sampling using the Environmental Sample Processor and a small-scale mixing experiment with lower euphotic zone water to determine how individual populations respond to mixing. Transcriptional responses were measured using the MicroTOOLs (Microbiological Targets for Ocean Observing Laboratories) microarray, which targets all three domains of life and viruses. The experiment showed that mixing substantially affects photosynthetic taxa as expected, but surprisingly also showed that populations respond differently to unfiltered deep water which contains particles (organisms and detritus) compared to filtered deep water that only contains nutrients and viruses, pointing to the impact of biological interactions associated with these events. Comparison between experimental and in situ population transcription patterns indicated that manipulated populations can serve as analogs for natural populations, and that natural populations may be frequently or continuously responding to nutrients from deeper waters. Finally, this study also shows that the microarray approach, which is complementary to metatranscriptomic sequencing, is useful for determining the physiological status of in situ microbial communities.
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Affiliation(s)
- J C Robidart
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, CA, USA.,National Oceanography Centre, Southampton, UK
| | - J D Magasin
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, CA, USA
| | - I N Shilova
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, CA, USA.,Second Genome, South San Francisco, CA, USA
| | - K A Turk-Kubo
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, CA, USA
| | - S T Wilson
- Daniel K. Inouye Center for Microbial Oceanography: Research and Education, Department of Oceanography, University of Hawai'i at Mānoa, Honolulu, HI, USA.,Department of Oceanography, School of Ocean and Earth Science and Technology, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - D M Karl
- Daniel K. Inouye Center for Microbial Oceanography: Research and Education, Department of Oceanography, University of Hawai'i at Mānoa, Honolulu, HI, USA.,Department of Oceanography, School of Ocean and Earth Science and Technology, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - C A Scholin
- Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA
| | - J P Zehr
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, CA, USA.
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9
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Markussen T, Happel EM, Teikari JE, Huchaiah V, Alneberg J, Andersson AF, Sivonen K, Riemann L, Middelboe M, Kisand V. Coupling biogeochemical process rates and metagenomic blueprints of coastal bacterial assemblages in the context of environmental change. Environ Microbiol 2018; 20:3083-3099. [PMID: 30084235 DOI: 10.1111/1462-2920.14371] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 07/31/2018] [Accepted: 08/01/2018] [Indexed: 11/28/2022]
Abstract
Bacteria are major drivers of biogeochemical nutrient cycles and energy fluxes in marine environments, yet how bacterial communities respond to environmental change is not well known. Metagenomes allow examination of genetic responses of the entire microbial community to environmental change. However, it is challenging to link metagenomes directly to biogeochemical process rates. Here, we investigate metagenomic responses in natural bacterioplankton communities to simulated environmental stressors in the Baltic Sea, including increased river water input, increased nutrient concentration, and reduced oxygen level. This allowed us to identify informative prokaryotic gene markers, responding to environmental perturbation. Our results demonstrate that metagenomic and metabolic changes in bacterial communities in response to environmental stressors are influenced both by the initial community composition and by the biogeochemical factors shaping the functional response. Furthermore, the different sources of dissolved organic matter (DOM) had the largest impact on metagenomic blueprint. Most prominently, changes in DOM loads influenced specific transporter types reflecting the substrate availability and DOC assimilation and consumption pathways. The results provide new knowledge for developing models of ecosystem structure and biogeochemical cycling in future climate change scenarios and advance our exploration of the potential use of marine microorganisms as markers for environmental conditions.
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Affiliation(s)
- Trine Markussen
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Elisabeth M Happel
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Jonna E Teikari
- Department of Microbiology, University of Helsinki, Helsinki, Finland
| | - Vimala Huchaiah
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Johannes Alneberg
- KTH Royal Institute of Technology, Science for Life Laboratory, School of Biotechnology, Stockholm, Sweden
| | - Anders F Andersson
- KTH Royal Institute of Technology, Science for Life Laboratory, School of Biotechnology, Stockholm, Sweden
| | - Kaarina Sivonen
- Department of Microbiology, University of Helsinki, Helsinki, Finland
| | - Lasse Riemann
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Mathias Middelboe
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Veljo Kisand
- Institute of Technology, University of Tartu, Tartu, Estonia
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10
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Bharudin I, Abu Bakar MF, Hashim NHF, Mat Isa MN, Alias H, Firdaus-Raih M, Md Illias R, Najimudin N, Mahadi NM, Abu Bakar FD, Abdul Murad AM. Unravelling the adaptation strategies employed by Glaciozyma antarctica PI12 on Antarctic sea ice. MARINE ENVIRONMENTAL RESEARCH 2018; 137:169-176. [PMID: 29598997 DOI: 10.1016/j.marenvres.2018.03.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 03/09/2018] [Accepted: 03/19/2018] [Indexed: 06/08/2023]
Abstract
Glaciozyma antarctica PI12, is a psychrophilic yeast isolated from Antarctic sea. In this work, Expressed Sequence Tags (EST) from cells exposed to three different temperatures; 15 °C, 0 °C and -12 °C were generated to identify genes associated with cold adaptation. A total of 5376 clones from each library were randomly picked and sequenced. Comparative analyses from the resulting ESTs in each condition identified several groups of genes required for cold adaptation. Additionally, 319 unique transcripts that encoded uncharacterised functions were identified in the -12 °C library and are currently unique to G. antarctica. Gene expression analysis using RT-qPCR revealed two of the unknown genes to be up-regulated at -12 °C compared to 0 °C and 15 °C. These findings further contribute to the collective knowledge into G. antarctica cold adaptation and as a resource for understanding the ecological and physiological tolerance of psychrophilic microbes in general.
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Affiliation(s)
- Izwan Bharudin
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600, UKM Bangi, Selangor, Malaysia.
| | | | - Noor Haza Fazlin Hashim
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600, UKM Bangi, Selangor, Malaysia
| | - Mohd Noor Mat Isa
- Malaysia Genome Institute, Jalan Bangi Lama, 43000, Kajang, Selangor, Malaysia
| | - Halimah Alias
- Malaysia Genome Institute, Jalan Bangi Lama, 43000, Kajang, Selangor, Malaysia
| | - Mohd Firdaus-Raih
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600, UKM Bangi, Selangor, Malaysia; Institute of Systems Biology, Universiti Kebangsaan Malaysia, 43600, UKM Bangi, Selangor, Malaysia
| | - Rosli Md Illias
- Department of Biosciences Engineering, Faculty of Chemical & Natural Resources Engineering, Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia
| | - Nazalan Najimudin
- School of Biological Sciences, Universiti Sains Malaysia, 11800, Penang, Malaysia
| | - Nor Muhammad Mahadi
- Malaysia Genome Institute, Jalan Bangi Lama, 43000, Kajang, Selangor, Malaysia
| | - Farah Diba Abu Bakar
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600, UKM Bangi, Selangor, Malaysia
| | - Abdul Munir Abdul Murad
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600, UKM Bangi, Selangor, Malaysia
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11
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Nitrogen Cycle Evaluation (NiCE) Chip for Simultaneous Analysis of Multiple N Cycle-Associated Genes. Appl Environ Microbiol 2018. [PMID: 29427421 DOI: 10.1128/aem.02615‐17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Various microorganisms play key roles in the nitrogen (N) cycle. Quantitative PCR (qPCR) and PCR amplicon sequencing of N cycle functional genes allow us to analyze the abundance and diversity of microbes responsible for N-transforming reactions in various environmental samples. However, analysis of multiple target genes can be cumbersome and expensive. PCR-independent analysis, such as metagenomics and metatranscriptomics, is useful but expensive, especially when we analyze multiple samples and try to detect N cycle functional genes present at a relatively low abundance. Here, we present the application of microfluidic qPCR chip technology to simultaneously quantify and prepare amplicon sequence libraries for multiple N cycle functional genes as well as taxon-specific 16S rRNA gene markers for many samples. This approach, named the nitrogen cycle evaluation (NiCE) chip, was evaluated by using DNA from pure and artificially mixed bacterial cultures and by comparing the results with those obtained by conventional qPCR and amplicon sequencing methods. Quantitative results obtained by the NiCE chip were comparable to those obtained by conventional qPCR. In addition, the NiCE chip was successfully applied to examine the abundance and diversity of N cycle functional genes in wastewater samples. Although nonspecific amplification was detected on the NiCE chip, this can be overcome by optimizing the primer sequences in the future. As the NiCE chip can provide a high-throughput format to quantify and prepare sequence libraries for multiple N cycle functional genes, this tool should advance our ability to explore N cycling in various samples.IMPORTANCE We report a novel approach, namely, the nitrogen cycle evaluation (NiCE) chip, by using microfluidic qPCR chip technology. By sequencing the amplicons recovered from the NiCE chip, we can assess the diversities of N cycle functional genes. The NiCE chip technology is applicable to analysis of the temporal dynamics of N cycle gene transcription in wastewater treatment bioreactors. The NiCE chip can provide a high-throughput format to quantify and prepare sequence libraries for multiple N cycle functional genes. While there is room for future improvement, this tool should significantly advance our ability to explore the N cycle in various environmental samples.
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12
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Nitrogen Cycle Evaluation (NiCE) Chip for Simultaneous Analysis of Multiple N Cycle-Associated Genes. Appl Environ Microbiol 2018; 84:AEM.02615-17. [PMID: 29427421 DOI: 10.1128/aem.02615-17] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 01/28/2018] [Indexed: 01/20/2023] Open
Abstract
Various microorganisms play key roles in the nitrogen (N) cycle. Quantitative PCR (qPCR) and PCR amplicon sequencing of N cycle functional genes allow us to analyze the abundance and diversity of microbes responsible for N-transforming reactions in various environmental samples. However, analysis of multiple target genes can be cumbersome and expensive. PCR-independent analysis, such as metagenomics and metatranscriptomics, is useful but expensive, especially when we analyze multiple samples and try to detect N cycle functional genes present at a relatively low abundance. Here, we present the application of microfluidic qPCR chip technology to simultaneously quantify and prepare amplicon sequence libraries for multiple N cycle functional genes as well as taxon-specific 16S rRNA gene markers for many samples. This approach, named the nitrogen cycle evaluation (NiCE) chip, was evaluated by using DNA from pure and artificially mixed bacterial cultures and by comparing the results with those obtained by conventional qPCR and amplicon sequencing methods. Quantitative results obtained by the NiCE chip were comparable to those obtained by conventional qPCR. In addition, the NiCE chip was successfully applied to examine the abundance and diversity of N cycle functional genes in wastewater samples. Although nonspecific amplification was detected on the NiCE chip, this can be overcome by optimizing the primer sequences in the future. As the NiCE chip can provide a high-throughput format to quantify and prepare sequence libraries for multiple N cycle functional genes, this tool should advance our ability to explore N cycling in various samples.IMPORTANCE We report a novel approach, namely, the nitrogen cycle evaluation (NiCE) chip, by using microfluidic qPCR chip technology. By sequencing the amplicons recovered from the NiCE chip, we can assess the diversities of N cycle functional genes. The NiCE chip technology is applicable to analysis of the temporal dynamics of N cycle gene transcription in wastewater treatment bioreactors. The NiCE chip can provide a high-throughput format to quantify and prepare sequence libraries for multiple N cycle functional genes. While there is room for future improvement, this tool should significantly advance our ability to explore the N cycle in various environmental samples.
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13
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Phosphate insensitive aminophosphonate mineralisation within oceanic nutrient cycles. ISME JOURNAL 2018; 12:973-980. [PMID: 29339823 DOI: 10.1038/s41396-017-0031-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 08/25/2017] [Accepted: 11/29/2017] [Indexed: 11/08/2022]
Abstract
Many areas of the ocean are nutrient-poor yet support large microbial populations, leading to intense competition for and recycling of nutrients. Organic phosphonates are frequently found in marine waters, but require specialist enzymes for catabolism. Previous studies have shown that the genes that encode these enzymes in marine systems are under Pho regulon control and so are repressed by inorganic phosphate. This has led to the conclusion that phosphonates are recalcitrant in much of the ocean, where phosphorus is not limiting despite the degradative genes being common throughout the marine environment. Here we challenge this paradigm and show, for the first time, that bacteria isolated from marine samples have the ability to mineralise 2-aminoethylphosphonate, the most common biogenic marine aminophosphonate, via substrate-inducible gene regulation rather than via Pho-regulated metabolism. Substrate-inducible, Pho-independent 2-aminoethylphosphonate catabolism therefore represents a previously unrecognised component of the oceanic carbon, nitrogen and phosphorus cycles.
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14
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McQuillan JS, Robidart JC. Molecular-biological sensing in aquatic environments: recent developments and emerging capabilities. Curr Opin Biotechnol 2017; 45:43-50. [DOI: 10.1016/j.copbio.2016.11.022] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 11/16/2016] [Accepted: 11/25/2016] [Indexed: 11/16/2022]
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15
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Stuart RK, Bundy R, Buck K, Ghassemain M, Barbeau K, Palenik B. Copper toxicity response influences mesotrophicSynechococcuscommunity structure. Environ Microbiol 2017; 19:756-769. [DOI: 10.1111/1462-2920.13630] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 11/17/2016] [Accepted: 11/19/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Rhona K. Stuart
- Scripps Institution of Oceanography, University of California at San Diego; La Jolla CA USA
| | - Randelle Bundy
- University of California at San Diego; La Jolla 92093 CA USA
| | - Kristen Buck
- Scripps Institution of Oceanography, University of California at San Diego; La Jolla CA USA
| | | | - Kathy Barbeau
- Scripps Institution of Oceanography, University of California at San Diego; La Jolla CA USA
| | - Brian Palenik
- Scripps Institution of Oceanography, University of California at San Diego; La Jolla CA USA
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16
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Su JQ, Cui L, Chen QL, An XL, Zhu YG. Application of genomic technologies to measure and monitor antibiotic resistance in animals. Ann N Y Acad Sci 2016; 1388:121-135. [DOI: 10.1111/nyas.13296] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 10/04/2016] [Accepted: 10/18/2016] [Indexed: 11/27/2022]
Affiliation(s)
- Jian-Qiang Su
- Key Lab of Urban Environment and Health, Institute of Urban Environment; Chinese Academy of Sciences; Xiamen China
| | - Li Cui
- Key Lab of Urban Environment and Health, Institute of Urban Environment; Chinese Academy of Sciences; Xiamen China
| | - Qing-Lin Chen
- Key Lab of Urban Environment and Health, Institute of Urban Environment; Chinese Academy of Sciences; Xiamen China
| | - Xin-Li An
- Key Lab of Urban Environment and Health, Institute of Urban Environment; Chinese Academy of Sciences; Xiamen China
| | - Yong-Guan Zhu
- Key Lab of Urban Environment and Health, Institute of Urban Environment; Chinese Academy of Sciences; Xiamen China
- State Key Lab of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences; Chinese Academy of Sciences; Beijing China
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17
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Burge CA, Friedman CS, Getchell R, House M, Lafferty KD, Mydlarz LD, Prager KC, Sutherland KP, Renault T, Kiryu I, Vega-Thurber R. Complementary approaches to diagnosing marine diseases: a union of the modern and the classic. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150207. [PMID: 26880839 PMCID: PMC4760137 DOI: 10.1098/rstb.2015.0207] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2015] [Indexed: 01/01/2023] Open
Abstract
Linking marine epizootics to a specific aetiology is notoriously difficult. Recent diagnostic successes show that marine disease diagnosis requires both modern, cutting-edge technology (e.g. metagenomics, quantitative real-time PCR) and more classic methods (e.g. transect surveys, histopathology and cell culture). Here, we discuss how this combination of traditional and modern approaches is necessary for rapid and accurate identification of marine diseases, and emphasize how sole reliance on any one technology or technique may lead disease investigations astray. We present diagnostic approaches at different scales, from the macro (environment, community, population and organismal scales) to the micro (tissue, organ, cell and genomic scales). We use disease case studies from a broad range of taxa to illustrate diagnostic successes from combining traditional and modern diagnostic methods. Finally, we recognize the need for increased capacity of centralized databases, networks, data repositories and contingency plans for diagnosis and management of marine disease.
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Affiliation(s)
- Colleen A Burge
- Institute of Marine and Environmental Technology, University of Maryland Baltimore County, 701 E Pratt Street, Baltimore, MD 21202, USA
| | - Carolyn S Friedman
- School of Aquatic and Fishery Sciences, University of Washington, Box 355020, Seattle, WA 98195, USA
| | - Rodman Getchell
- Department of Microbiology and Immunology, C4-177 Vet Med Center, College of Veterinary Medicine, Cornell University, 930 Campus Road, Ithaca, NY 14853, USA
| | - Marcia House
- Northwest Indian Fisheries Commission, 6730 Martin Way East, Olympia, WA 98516, USA
| | - Kevin D Lafferty
- US Geological Survey, Western Ecological Research Center, c/o Marine Science Institute, University of California, Santa Barbara, CA 93106, USA
| | - Laura D Mydlarz
- Department of Biology, University of Texas Arlington, 501 South Nedderman, Arlington, TX 76019, USA
| | - Katherine C Prager
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA Fogarty International Center, National Institutes of Health, Bethesda, MD 20892, USA
| | | | - Tristan Renault
- Ifremer, Département Ressources Biologiques et Environnement, rue de l'Ile d'Yeu, 44311 Nantes Cedex 03, France
| | - Ikunari Kiryu
- National Research Institute of Aquaculture, Fisheries Research Agency, Mie 516-0193, Japan
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18
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Shilova IN, Robidart JC, DeLong EF, Zehr JP. Genetic Diversity Affects the Daily Transcriptional Oscillations of Marine Microbial Populations. PLoS One 2016; 11:e0146706. [PMID: 26751368 PMCID: PMC4709009 DOI: 10.1371/journal.pone.0146706] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 12/21/2015] [Indexed: 11/18/2022] Open
Abstract
Marine microbial communities are genetically diverse but have robust synchronized daily transcriptional patterns at the genus level that are similar across a wide variety of oceanic regions. We developed a microarray-inspired gene-centric approach to resolve transcription of closely-related but distinct strains/ecotypes in high-throughput sequence data. Applying this approach to the existing metatranscriptomics datasets collected from two different oceanic regions, we found unique and variable patterns of transcription by individual taxa within the abundant picocyanobacteria Prochlorococcus and Synechococcus, the alpha Proteobacterium Pelagibacter and the eukaryotic picophytoplankton Ostreococcus. The results demonstrate that marine microbial taxa respond differentially to variability in space and time in the ocean. These intra-genus individual transcriptional patterns underlie whole microbial community responses, and the approach developed here facilitates deeper insights into microbial population dynamics.
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Affiliation(s)
- Irina N. Shilova
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Julie C. Robidart
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Edward F. DeLong
- School of Ocean and Earth Science and Technology, University of Hawai’i at Manoa, Honolulu, Hawaii, United States of America
| | - Jonathan P. Zehr
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, California, United States of America
- * E-mail:
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19
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High-throughput metagenomic technologies for complex microbial community analysis: open and closed formats. mBio 2015; 6:mBio.02288-14. [PMID: 25626903 PMCID: PMC4324309 DOI: 10.1128/mbio.02288-14] [Citation(s) in RCA: 232] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Understanding the structure, functions, activities and dynamics of microbial communities in natural environments is one of the grand challenges of 21st century science. To address this challenge, over the past decade, numerous technologies have been developed for interrogating microbial communities, of which some are amenable to exploratory work (e.g., high-throughput sequencing and phenotypic screening) and others depend on reference genes or genomes (e.g., phylogenetic and functional gene arrays). Here, we provide a critical review and synthesis of the most commonly applied “open-format” and “closed-format” detection technologies. We discuss their characteristics, advantages, and disadvantages within the context of environmental applications and focus on analysis of complex microbial systems, such as those in soils, in which diversity is high and reference genomes are few. In addition, we discuss crucial issues and considerations associated with applying complementary high-throughput molecular technologies to address important ecological questions.
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20
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Abstract
The biodiversity of phytoplankton is a core measurement of the state and activity of marine ecosystems. In the context of historical approaches, we review recent major advances in the technologies that have enabled deeper characterization of the biodiversity of phytoplankton. In particular, high-throughput sequencing of single loci/genes, genomes, and communities (metagenomics) has revealed exceptional phylogenetic and genomic diversity whose breadth is not fully constrained. Other molecular tools-such as fingerprinting, quantitative polymerase chain reaction, and fluorescence in situ hybridization-have provided additional insight into the dynamics of this diversity in the context of environmental variability. Techniques for characterizing the functional diversity of community structure through targeted or untargeted approaches based on RNA or protein have also greatly advanced. A wide range of techniques is now available for characterizing phytoplankton communities, and these tools will continue to advance through ongoing improvements in both technology and data interpretation.
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Affiliation(s)
- Zackary I Johnson
- Marine Laboratory (Nicholas School of the Environment) and Department of Biology, Duke University, Beaufort, North Carolina 28516;
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21
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Karl DM, Church MJ. Microbial oceanography and the Hawaii Ocean Time-series programme. Nat Rev Microbiol 2014; 12:699-713. [PMID: 25157695 DOI: 10.1038/nrmicro3333] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The Hawaii Ocean Time-series (HOT) programme has been tracking microbial and biogeochemical processes in the North Pacific Subtropical Gyre since October 1988. The near-monthly time series observations have revealed previously undocumented phenomena within a temporally dynamic ecosystem that is vulnerable to climate change. Novel microorganisms, genes and unexpected metabolic pathways have been discovered and are being integrated into our evolving ecological paradigms. Continued research, including higher-frequency observations and at-sea experimentation, will help to provide a comprehensive scientific understanding of microbial processes in the largest biome on Earth.
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Affiliation(s)
- David M Karl
- Daniel K. Inouye Center for Microbial Oceanography: Research and Education, University of Hawaii, 1950 East-West Road, Honolulu, Hawaii 96822, USA
| | - Matthew J Church
- Daniel K. Inouye Center for Microbial Oceanography: Research and Education, University of Hawaii, 1950 East-West Road, Honolulu, Hawaii 96822, USA
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