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Lidbury IDEA, Hitchcock A, Groenhof SRM, Connolly AN, Moushtaq L. New insights in bacterial organophosphorus cycling: From human pathogens to environmental bacteria. Adv Microb Physiol 2024; 84:1-49. [PMID: 38821631 DOI: 10.1016/bs.ampbs.2023.12.003] [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] [Indexed: 06/02/2024]
Abstract
In terrestrial and aquatic ecosystems, phosphorus (P) availability controls primary production, with consequences for climate regulation and global food security. Understanding the microbial controls on the global P cycle is a prerequisite for minimising our reliance on non-renewable phosphate rock reserves and reducing pollution associated with excessive P fertiliser use. This recognised importance has reinvigorated research into microbial P cycling, which was pioneered over 75 years ago through the study of human pathogenic bacteria-host interactions. Immobilised organic P represents a significant fraction of the total P pool. Hence, microbes have evolved a plethora of mechanisms to transform this fraction into labile inorganic phosphate, the building block for numerous biological molecules. The 'genomics era' has revealed an extraordinary diversity of organic P cycling genes exist in the environment and studies going 'back to the lab' are determining how this diversity relates to function. Through this integrated approach, many hitherto unknown genes and proteins that are involved in microbial P cycling have been discovered. Not only do these fundamental discoveries push the frontier of our knowledge, but several examples also provide exciting opportunities for biotechnology and present possible solutions for improving the sustainability of how we grow our food, both locally and globally. In this review, we provide a comprehensive overview of bacterial organic P cycling, covering studies on human pathogens and how this knowledge is informing new discoveries in environmental microbiology.
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Affiliation(s)
- Ian D E A Lidbury
- Molecular Microbiology - Biochemistry and Disease, School of Biosciences, The University of Sheffield, Sheffield, United Kingdom.
| | - Andrew Hitchcock
- Molecular Microbiology - Biochemistry and Disease, School of Biosciences, The University of Sheffield, Sheffield, United Kingdom; Plants, Photosynthesis, and Soil, School of Biosciences, The University of Sheffield, Sheffield, United Kingdom
| | - Sophie R M Groenhof
- Molecular Microbiology - Biochemistry and Disease, School of Biosciences, The University of Sheffield, Sheffield, United Kingdom
| | - Alex N Connolly
- Molecular Microbiology - Biochemistry and Disease, School of Biosciences, The University of Sheffield, Sheffield, United Kingdom
| | - Laila Moushtaq
- Molecular Microbiology - Biochemistry and Disease, School of Biosciences, The University of Sheffield, Sheffield, United Kingdom
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Park S, Dingemans J, Sauer K. Manganese Acts as an Environmental Inhibitor of Pseudomonas aeruginosa Biofilm Development by Inducing Dispersion and Modulating c-di-GMP and Exopolysaccharide Production via RbdA. J Bacteriol 2023; 205:e0000323. [PMID: 37199658 PMCID: PMC10294637 DOI: 10.1128/jb.00003-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 04/27/2023] [Indexed: 05/19/2023] Open
Abstract
The opportunistic human pathogen Pseudomonas aeruginosa causes chronic infections that involve multicellular aggregates called biofilms. Biofilm formation is modulated by the host environment and the presence of cues and/or signals, likely affecting the pool of the bacterial second messenger cyclic diguanylate monophosphate (c-di-GMP). The manganese ion Mn2+ is a divalent metal cation that is essential for pathogenic bacterial survival and replication during the infection in a host organism. In this study, we investigated how Mn2+ alters P. aeruginosa biofilm formation via the regulation of c-di-GMP levels. Exposure to Mn2+ was found to temporally enhance attachment but impair subsequent biofilm development, apparent by reduced biofilm biomass accumulation and lack of microcolony formation due to the induction of dispersion. Moreover, exposure to Mn2+ coincided with reduced production of the exopolysaccharides Psl and Pel, decreased transcriptional abundance of pel and psl, and decreased levels of c-di-GMP. To determine whether the effect of Mn2+ was linked to the activation of phosphodiesterases (PDEs), we screened several PDE mutants for Mn2+-dependent phenotypes (attachment and polysaccharide production) as well as PDE activity. The screen revealed that the PDE RbdA is activated by Mn2+ and is responsible for Mn2+-dependent attachment, inhibition of Psl production, and dispersion. Taken together, our findings suggest Mn2+ is an environmental inhibitor of P. aeruginosa biofilm development that acts through the PDE RbdA to modulate c-di-GMP levels, thereby impeding polysaccharide production and biofilm formation but enhancing dispersion. IMPORTANCE While diverse environmental conditions such as the availability of metal ions have been shown to affect biofilm development, little is known about the mechanism. Here, we demonstrate that Mn2+ affects Pseudomonas aeruginosa biofilm development by stimulating phosphodiesterase RbdA activity to reduce the signaling molecule c-di-GMP levels, thereby hindering polysaccharide production and biofilm formation but enhancing dispersion. Our findings demonstrate that Mn2+ acts as an environmental inhibitor of P. aeruginosa biofilms, further suggesting manganese to be a promising new antibiofilm factor.
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Affiliation(s)
- Soyoung Park
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
| | - Jozef Dingemans
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
| | - Karin Sauer
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
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The Proteobacterial Methanotroph Methylosinus trichosporium OB3b Remodels Membrane Lipids in Response to Phosphate Limitation. mBio 2022; 13:e0024722. [PMID: 35575546 PMCID: PMC9239053 DOI: 10.1128/mbio.00247-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
Methane is a potent greenhouse gas in the atmosphere, and its concentration has continued to increase in recent decades. Aerobic methanotrophs, bacteria that use methane as the sole carbon source, are an important biological sink for methane, and they are widely distributed in the natural environment. However, relatively little is known on how methanotroph activity is regulated by nutrients, particularly phosphorus (P). P is the principal nutrient constraining plant and microbial productivity in many ecosystems, ranging from agricultural land to the open ocean. Using a model methanotrophic bacterium, Methylosinus trichosporium OB3b, we demonstrate here that this bacterium can produce P-free glycolipids to replace membrane phospholipids in response to P limitation. The formation of the glycolipid monoglucuronic acid diacylglycerol requires plcP-agt genes since the plcP-agt mutant is unable to produce this glycolipid. This plcP-agt-mediated lipid remodeling pathway appears to be important for M. trichosporium OB3b to cope with P stress, and the mutant grew significantly slower under P limitation. Interestingly, comparative genomics analysis shows that the ability to perform lipid remodeling appears to be a conserved trait in proteobacterial methanotrophs; indeed, plcP is found in all proteobacterial methanotroph genomes, and plcP transcripts from methanotrophs are readily detectable in metatranscriptomics data sets. Together, our study provides new insights into the adaptation to P limitation in this ecologically important group of bacteria.
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Wang X, Browning TJ, Achterberg EP, Gledhill M. Phosphorus Limitation Enhances Diazotroph Zinc Quotas. Front Microbiol 2022; 13:853519. [PMID: 35531286 PMCID: PMC9069106 DOI: 10.3389/fmicb.2022.853519] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 02/07/2022] [Indexed: 11/22/2022] Open
Abstract
Trichodesmium spp. is a colonial diazotrophic cyanobacterium found in the oligotrophic (sub)tropical oceans, where dissolved inorganic phosphorus (DIP) can be depleted. To cope with low P concentrations, P can be scavenged from the dissolved organic P (DOP) pool. This requires the deployment of multiple enzymes activated by trace metals, potentially enhancing metal requirements under stronger P limitations. To test this, we grew Trichodesmium under trace-metal-controlled conditions, where P was supplied as either DIP or DOP (methylphosphonic acid). Mean steady-state biomass under the DOP treatment was only 40% of that grown under equivalent DIP supply, carbon normalized alkaline phosphorus activity was elevated 4-fold, and the zinc (Zn)–carbon ratio was elevated 3.5-fold. Our finding matches the known, dominant Zn requirement across a diversity of enzymes involved in P stress responses and supports an important interaction in the oceanic cycles of these two nutrients.
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A Glycolipid Glycosyltransferase with Broad Substrate Specificity from the Marine Bacterium " Candidatus Pelagibacter sp." Strain HTCC7211. Appl Environ Microbiol 2021; 87:e0032621. [PMID: 33931419 PMCID: PMC8231724 DOI: 10.1128/aem.00326-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
In the marine environment, phosphorus availability significantly affects the lipid composition in many cosmopolitan marine heterotrophic bacteria, including members of the SAR11 clade and the Roseobacter clade. Under phosphorus stress conditions, nonphosphorus sugar-containing glycoglycerolipids are substitutes for phospholipids in these bacteria. Although these glycoglycerolipids play an important role as surrogates for phospholipids under phosphate deprivation, glycoglycerolipid synthases in marine microbes are poorly studied. In the present study, we biochemically characterized a glycolipid glycosyltransferase (GTcp) from the marine bacterium “Candidatus Pelagibacter sp.” strain HTCC7211, a member of the SAR11 clade. Our results showed that GTcp is able to act as a multifunctional enzyme by synthesizing different glycoglycerolipids with UDP-glucose, UDP-galactose, or UDP-glucuronic acid as sugar donors and diacylglycerol (DAG) as the acceptor. Analyses of enzyme kinetic parameters demonstrated that Mg2+ notably changes the enzyme’s affinity for UDP-glucose, which improves its catalytic efficiency. Homology modeling and mutational analyses revealed binding sites for the sugar donor and the diacylglycerol lipid acceptor, which provided insights into the retaining mechanism of GTcp with its GT-B fold. A phylogenetic analysis showed that GTcp and its homologs form a group in the GT4 glycosyltransferase family. These results not only provide new insights into the glycoglycerolipid synthesis mechanism in lipid remodeling but also describe an efficient enzymatic tool for the future synthesis of bioactive molecules. IMPORTANCE The bilayer formed by membrane lipids serves as the containment unit for living microbial cells. In the marine environment, it has been firmly established that phytoplankton and heterotrophic bacteria can replace phospholipids with nonphosphorus sugar-containing glycoglycerolipids in response to phosphorus limitation. However, little is known about how these glycoglycerolipids are synthesized. Here, we determined the biochemical characteristics of a glycolipid glycosyltransferase (GTcp) from the marine bacterium “Candidatus Pelagibacter sp.” strain HTCC7211. GTcp and its homologs form a group in the GT4 glycosyltransferase family and can synthesize neutral glycolipids (monoglucosyl-1,2-diacyl-sn-glycerol [MGlc-DAG] and monogalactosyl [MGal]-DAG) and monoglucuronic acid diacylglycerol (MGlcA-DAG). We also uncovered the key residues for DAG binding through molecular docking, site-direct mutagenesis, and subsequent enzyme activity assays. Our data provide new insights into the glycoglycerolipid synthesis mechanism in lipid remodeling.
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A Riemerella anatipestifer Metallophosphoesterase That Displays Phosphatase Activity and Is Associated with Virulence. Appl Environ Microbiol 2021; 87:AEM.00086-21. [PMID: 33741629 DOI: 10.1128/aem.00086-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 02/27/2021] [Indexed: 11/20/2022] Open
Abstract
Riemerella anatipestifer is an important pathogen of waterfowl, causing septicemic and exudative diseases. In our previous study, we demonstrated that bacterial virulence and secretion proteins of the type IX secretion system (T9SS) mutant strains Yb2ΔgldK and Yb2ΔgldM were significantly reduced, in comparison to those of wild-type strain Yb2. In this study, the T9SS secretion protein AS87_RS00980, which is absent from the secretion proteins of Yb2ΔgldK and Yb2ΔgldM, was investigated by construction of gene mutation and complementation strains. The virulence assessment showed >1,000-fold attenuated virulence and significantly reduced bacterial loads in the blood of ducks infected with Yb2Δ00980, the AS87_RS00980 gene deletion mutant strain. Bacterial virulence was recovered in complementation strain cYb2Δ00980 Further study indicated that the T9SS secretion protein AS87_RS00980 is a metallophosphoesterase (MPPE), which displayed phosphatase activity and was cytomembrane localized. Moreover, the optimal reactive pH and temperature were determined to be 7.0 and 60°C, respectively, and the Km and V max were determined to be 3.53 mM and 198.1 U/mg. The rMPPE activity was activated by Zn2+ and Cu2+ but inhibited by Fe3+, Fe2+, and EDTA. There are five conserved sites, namely, N267, H268 H351, H389, and H391, in the metallophosphatase domain. Mutant proteins Y267-rMPPE and Y268-rMPPE retained 29.30% and 19.81% relative activity, respectively, and mutant proteins Y351-rMPPE, Y389-rMPPE, and Y391-rMPPE lost almost all MPPE activity. Taken together, these results indicate that the R. anatipestifer AS87_RS00980 gene encodes an MPPE that is a secretion protein of T9SS that plays an important role in bacterial virulence.IMPORTANCE Riemerella anatipestifer T9SS was recently discovered to be associated with bacterial gliding motility and secretion of virulence factors. Several T9SS genes have been identified, but no effector has been reported in R. anatipestifer to date. In this study, we identified the T9SS secretion protein AS87_RS00980 as an MPPE that displays phosphatase activity and is associated with bacterial virulence. The enzymatic activity of the rMPPE was determined, and the Km and V max were 3.53 mM and 198.1 U/mg, respectively. Five conserved sites were also identified. The AS87_RS00980 gene deletion mutant strain was attenuated >1,000-fold, indicating that MPPE is an important virulence factor. In summary, we identified that the R. anatipestifer AS87_RS00980 gene encodes an important T9SS effector, MPPE, which plays an important role in bacterial virulence.
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Jiang J, Wang F, Wang L, Xiao J, Guo D. Manganese Chloride Exposure Causes Disorder of Energy Metabolism and Induces Oxidative Stress and Autophagy in Chicken Liver. Biol Trace Elem Res 2020; 197:254-261. [PMID: 31916180 DOI: 10.1007/s12011-019-01960-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 10/28/2019] [Indexed: 12/13/2022]
Abstract
Manganese (Mn) pollution is an important environmental problem because of the potential toxicity to human and animal health. However, the effects of Mn on energy metabolism and autophagy are not clear. Consequently, we examined the effects of excessive and chronic exposure to Mn on liver function, oxidative stress, respiratory chain complex activity, and autophagy in chicken liver. Our results indicated that the accumulation of Mn in the liver and levels of AST and ALT in the serum of the Mn-exposed group were significantly higher (P < 0.05) than those in the control group at 90 days; the activities of GSH-Px, SOD, CAT, Na+-K+-ATPase, Mg2+-ATPase, Ca2+-ATPase, and respiratory chain complexes (I, II, III) in the Mn-exposed group were significantly decreased (P < 0.05) compared to the control group. However, the MDA content, NO content, iNOS activity, mRNA and protein levels of iNOS, and autophagy-related genes in the Mn-exposed group were significantly increased (P < 0.05) compared to the control group. In contrast, the mRNA level and protein expression of mTOR were significantly decreased (P < 0.05) compared to the control group. Furthermore, the characteristic autophagic vacuolar organelles were observed in the Mn-exposed group. These results suggested that excess Mn exposure can cause a disorder of energy metabolism by mitochondrial injury and induce oxidative stress and autophagy, which eventually lead to liver damage.
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Affiliation(s)
- Jiancheng Jiang
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, No. 5 Xinfeng Road, Sartu District, Daqing, 163319, China
| | - Fengfeng Wang
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, No. 5 Xinfeng Road, Sartu District, Daqing, 163319, China
| | - Lina Wang
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, No. 5 Xinfeng Road, Sartu District, Daqing, 163319, China
| | - Jiawei Xiao
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, No. 5 Xinfeng Road, Sartu District, Daqing, 163319, China
| | - Donghua Guo
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, No. 5 Xinfeng Road, Sartu District, Daqing, 163319, China.
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Insights into the Mn 2+ Binding Site in the Agmatinase-Like Protein (ALP): A Critical Enzyme for the Regulation of Agmatine Levels in Mammals. Int J Mol Sci 2020; 21:ijms21114132. [PMID: 32531922 PMCID: PMC7313459 DOI: 10.3390/ijms21114132] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/01/2020] [Accepted: 06/05/2020] [Indexed: 11/21/2022] Open
Abstract
Agmatine is a neurotransmitter with anticonvulsant, anti-neurotoxic and antidepressant-like effects, in addition it has hypoglycemic actions. Agmatine is converted to putrescine and urea by agmatinase (AGM) and by an agmatinase-like protein (ALP), a new type of enzyme which is present in human and rodent brain tissues. Recombinant rat brain ALP is the only mammalian protein that exhibits significant agmatinase activity in vitro and generates putrescine under in vivo conditions. ALP, despite differing in amino acid sequence from all members of the ureohydrolase family, is strictly dependent on Mn2+ for catalytic activity. However, the Mn2+ ligands have not yet been identified due to the lack of structural information coupled with the low sequence identity that ALPs display with known ureohydrolases. In this work, we generated a structural model of the Mn2+ binding site of the ALP and we propose new putative Mn2+ ligands. Then, we cloned and expressed a sequence of 210 amino acids, here called the “central-ALP”, which include the putative ligands of Mn2+. The results suggest that the central-ALP is catalytically active, as agmatinase, with an unaltered Km for agmatine and a decreased kcat. Similar to wild-type ALP, central-ALP is activated by Mn2+ with a similar affinity. Besides, a simple mutant D217A, a double mutant E288A/K290A, and a triple mutant N213A/Q215A/D217A of these putative Mn2+ ligands result on the loss of ALP agmatinase activity. Our results indicate that the central-ALP contains the active site for agmatine hydrolysis, as well as that the residues identified are relevant for the ALP catalysis.
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Ullah M, Li H, Sun SW, Weng CH, Zhang H, Zhu H. Polyvinyl alcohol degradation by Bacillus cereus RA23 from oil sludge sample. 3 Biotech 2019; 9:350. [PMID: 31501751 PMCID: PMC6722167 DOI: 10.1007/s13205-019-1882-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 08/22/2019] [Indexed: 10/26/2022] Open
Abstract
A novel polyvinyl alcohol (PVA)-degrading strain Bacillus cereus RA23 was isolated from an oil sludge sample and environmental factors affecting its PVA degradation efficiency were optimized in detail. Inorganic nitrogen source, ammonium chloride (NH4Cl), was found to be the best nitrogen source and enhanced the PVA degradation rate greatly. The optimal medium for PVA biodegradation consisted of (g/L) PVA 1, NH4Cl 1, K2HPO4 1.6, MgSO4·7H2O 0.05, FeSO4·6H2O 0.02, CaCl2 0.05, NaCl 0.02. The optimal temperature and pH for PVA biodegradation by strain RA23 was 28 °C and 7.0, respectively, and 85% of 0.1% PVA was degraded after 5 days under these conditions. FTIR studies showed that the carboxylic acids (possibly including aldehyde or ketone) could be the intermediate product of PVA biodegradation. The investigation of strain RA23 for PVA degradation will provide important information to facilitate the removal of wastewater pollution in industrial zones.
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Affiliation(s)
- Munzer Ullah
- Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao, 266580 People’s Republic of China
| | - Hui Li
- Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao, 266580 People’s Republic of China
| | - Shi-Wei Sun
- Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao, 266580 People’s Republic of China
| | - Cai-Hong Weng
- Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao, 266580 People’s Republic of China
| | - Hong Zhang
- Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao, 266580 People’s Republic of China
| | - Hu Zhu
- Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao, 266580 People’s Republic of China
- Fujian Provincial Key Laboratory of Advanced Materials Oriented Chemical Engineering, Fujian Provincial University Engineering Research Center of Industrial Biocatalysis, College of Chemistry and Materials Science, Fujian Normal University, 32 Shangsan Road, Fuzhou, 350007 People’s Republic of China
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Wu M, McCain JSP, Rowland E, Middag R, Sandgren M, Allen AE, Bertrand EM. Manganese and iron deficiency in Southern Ocean Phaeocystis antarctica populations revealed through taxon-specific protein indicators. Nat Commun 2019; 10:3582. [PMID: 31395884 PMCID: PMC6687791 DOI: 10.1038/s41467-019-11426-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 07/15/2019] [Indexed: 11/10/2022] Open
Abstract
Iron and light are recognized as limiting factors controlling Southern Ocean phytoplankton growth. Recent field-based evidence suggests, however, that manganese availability may also play a role. Here we examine the influence of iron and manganese on protein expression and physiology in Phaeocystis antarctica, a key Antarctic primary producer. We provide taxon-specific proteomic evidence to show that in-situ Southern Ocean Phaeocystis populations regularly experience stress due to combined low manganese and iron availability. In culture, combined low iron and manganese induce large-scale changes in the Phaeocystis proteome and result in reorganization of the photosynthetic apparatus. Natural Phaeocystis populations produce protein signatures indicating late-season manganese and iron stress, consistent with concurrently observed stimulation of chlorophyll production upon additions of manganese or iron. These results implicate manganese as an important driver of Southern Ocean productivity and demonstrate the utility of peptide mass spectrometry for identifying drivers of incomplete macronutrient consumption.
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Affiliation(s)
- Miao Wu
- Department of Biology, Dalhousie University, 1355 Oxford Street PO Box 15000, Halifax, B3H 4R2, NS, Canada
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Box 7015, 750 07, Uppsala, Sweden
| | - J Scott P McCain
- Department of Biology, Dalhousie University, 1355 Oxford Street PO Box 15000, Halifax, B3H 4R2, NS, Canada
| | - Elden Rowland
- Department of Biology, Dalhousie University, 1355 Oxford Street PO Box 15000, Halifax, B3H 4R2, NS, Canada
| | - Rob Middag
- Department of Ocean Systems, NIOZ Royal Netherlands Institute for Sea Research, and Utrecht University, P.O. Box 59, Den Burg, Texel, 1790 AB, Netherlands
| | - Mats Sandgren
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Box 7015, 750 07, Uppsala, Sweden
| | - Andrew E Allen
- Microbial and Environmental Genomics, J. Craig Venter Institute, 4120 Capricorn Lane, La Jolla, CA, 92037, USA
- Integrative Oceanography Division, Scripps Institution of Oceanography, University of California, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Erin M Bertrand
- Department of Biology, Dalhousie University, 1355 Oxford Street PO Box 15000, Halifax, B3H 4R2, NS, Canada.
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