Phosphate diester utilization by marine diazotrophs Trichodesmium erythraeum and Crocosphaera watsonii

2020 ◽  
Vol 85 ◽  
pp. 211-218
Author(s):  
T Yamaguchi ◽  
M Sato ◽  
N Gonda ◽  
K Takahashi ◽  
K Furuya
Keyword(s):  
Organic Phosphorus ◽  
Marine Phytoplankton ◽  
Trichodesmium Erythraeum ◽  
P Limitation ◽  
Phosphate Diester ◽  
Nitrophenyl Phosphate ◽  
Clonal Cultures ◽  
P Sources ◽  
Crocosphaera Watsonii

In the phosphate-depleted oligotrophic ocean, microbes utilize various dissolved organic phosphorus (P) compounds as alternative P sources, using enzymes such as alkaline phosphatases. However, knowledge of such P acquisition mechanisms is limited, especially in association with the physiology of nitrogen-fixing organisms, which play a substantial role in marine biogeochemical cycling. We show that nonaxenic clonal cultures of 2 oceanic diazotrophs, Trichodesmium erythraeum and Crocosphaera watsonii, have the ability to utilize phosphate diester as their sole P source, using a model artificial compound—bis-p-nitrophenyl phosphate (bisNPP). Although both diazotroph cultures likely preferred phosphate monoester to diester, the expressed diesterase activity was theoretically sufficient to fulfill their P demands, and they showed significant growth in bisNPP-added media. Interestingly, a distinct difference in their growth trends was observed, with faster onset of growth by C. watsonii and delayed onset of growth by T. erythraeum. This indicates that the C. watsonii consortium can effectively and rapidly assimilate in situ diesters as alternative P sources in the field. Nonetheless, when considering the poor bisNPP utilization reported from other marine phytoplankton taxa, our results indicate that the utilization of particular diester compounds is a notable and advantageous strategy for both diazotroph consortia to alleviate P limitation in the oligotrophic ocean.

scholarly journals Non-Conventional Metal Ion Cofactor Requirement of Dinoflagellate Alkaline Phosphatase and Translational Regulation by Phosphorus Limitation

2019 ◽  
Vol 7 (8) ◽  
pp. 232 ◽  
Author(s):  
Xin Lin ◽  
Chentao Guo ◽  
Ling Li ◽  
Tangcheng Li ◽  
Senjie Lin
Keyword(s):  
Alkaline Phosphatase ◽  
Metal Ion ◽  
Translational Regulation ◽  
Organic Phosphorus ◽  
Niche Differentiation ◽  
Phosphorus Limitation ◽  
Marine Phytoplankton ◽  
Phosphate Limitation ◽  
Dissolved Organic Phosphorus ◽  
Metal Cofactor

Alkaline phosphatase (AP) enables marine phytoplankton to utilize dissolved organic phosphorus (DOP) when dissolved inorganic phosphate (DIP) is depleted in the ocean. Dinoflagellate AP (Dino-AP) represents a newly classified atypical type of AP, PhoAaty. Despite While being a conventional AP, PhoAEC is known to recruit Zn2+ and Mg2+ in the active center, and the cofactors required by PhoAaty have been contended and remain unclear. In this study, we investigated the metal ion requirement of AP in five dinoflagellate species. After AP activity was eliminated by using EDTA to chelate metal ions, the enzymatic activity could be recovered by the supplementation of Ca2+, Mg2+ and Mn2+ in all cases but not by that of Zn2+. Furthermore, the same analysis conducted on the purified recombinant ACAAP (AP of Amphidinium carterae) verified that the enzyme could be activated by Ca2+, Mg2+, and Mn2+ but not Zn2+. We further developed an antiserum against ACAAP, and a western blot analysis using this antibody showed a remarkable up-regulation of ACAAP under a phosphate limitation, consistent with elevated AP activity. The unconventional metal cofactor requirement of Dino-AP may be an adaptation to trace metal limitations in the ocean, which warrants further research to understand the niche differentiation between dinoflagellates and other phytoplankton that use Zn–Mg AP in utilizing DOP.

scholarly journals Effect of incubation time and substrate concentration on N-uptake rates by phytoplankton in the Bay of Bengal

2005 ◽  
Vol 2 (5) ◽  
pp. 1331-1352
Author(s):  
S. Kumar ◽  
R. Ramesh ◽  
S. Sardesai ◽  
M. S. Sheshshayee
Keyword(s):  
Incubation Time ◽  
Uptake Rate ◽  
Nitrate Uptake ◽  
N Uptake ◽  
Marine Phytoplankton ◽  
Total Production ◽  
New Production ◽  
Urea Uptake ◽  
Uptake Rates

Abstract. We report here the results of three experiments, which are slight variations of the 15N method (JGOFS protocol) for determination of new production. The first two test the effect of (i) duration of incubation time and (ii) concentration of tracer added on the uptake rates of various N-species (nitrate, ammonium and urea) by marine phytoplankton; while the third compares in situ and deck incubations from dawn to dusk. Results indicate that nitrate uptake can be underestimated by experiments where incubation times shorter than 4h or when more than 10% of the ambient concentration of nitrate is added prior to incubation. The f-ratio increases from 0.28 to 0.42 when the incubation time increases from two to four hours. This may be due to the observed increase in the uptake rate of nitrate and decrease in the urea uptake rate. Unlike ammonium [y{=}2.07x{-}0.002\\, (r2=0.55)] and urea uptakes [y{=}1.88x{+}0.004 (r2=0.88)], the nitrate uptake decreases as the concentration of the substrate (x) increases, showing a negative correlation [y{=}-0.76x+0.05 (r2=0.86)], possibly due to production of glutamine, which might suppress nitrate uptake. This leads to decline in the f-ratio from 0.47 to 0.10, when concentration of tracer varies from 0.01 to 0.04μ M. The column integrated total productions are 519 mg C m-2 d-1 and 251 mg C m-2 d-1 for in situ and deck incubations, respectively. The 14C based production at the same location is ~200 mg C m-2 d-1, which is in closer agreement to the 15N based total production measured by deck incubation.

scholarly journals Metatranscriptome analyses indicate resource partitioning between diatoms in the field

2015 ◽  
Vol 112 (17) ◽  
pp. E2182-E2190 ◽  
Author(s):  
Harriet Alexander ◽  
Bethany D. Jenkins ◽  
Tatiana A. Rynearson ◽  
Sonya T. Dyhrman
Keyword(s):  
Resource Utilization ◽  
Resource Partitioning ◽  
Niche Partitioning ◽  
The United States ◽  
Narragansett Bay ◽  
Marine Phytoplankton ◽  
Transcriptional Responses ◽  
Gene Sets ◽  
Nutrient Amendment

Diverse communities of marine phytoplankton carry out half of global primary production. The vast diversity of the phytoplankton has long perplexed ecologists because these organisms coexist in an isotropic environment while competing for the same basic resources (e.g., inorganic nutrients). Differential niche partitioning of resources is one hypothesis to explain this “paradox of the plankton,” but it is difficult to quantify and track variation in phytoplankton metabolism in situ. Here, we use quantitative metatranscriptome analyses to examine pathways of nitrogen (N) and phosphorus (P) metabolism in diatoms that cooccur regularly in an estuary on the east coast of the United States (Narragansett Bay). Expression of known N and P metabolic pathways varied between diatoms, indicating apparent differences in resource utilization capacity that may prevent direct competition. Nutrient amendment incubations skewed N/P ratios, elucidating nutrient-responsive patterns of expression and facilitating a quantitative comparison between diatoms. The resource-responsive (RR) gene sets deviated in composition from the metabolic profile of the organism, being enriched in genes associated with N and P metabolism. Expression of the RR gene set varied over time and differed significantly between diatoms, resulting in opposite transcriptional responses to the same environment. Apparent differences in metabolic capacity and the expression of that capacity in the environment suggest that diatom-specific resource partitioning was occurring in Narragansett Bay. This high-resolution approach highlights the molecular underpinnings of diatom resource utilization and how cooccurring diatoms adjust their cellular physiology to partition their niche space.

Acceleration of the methanolysis of phosphate diesters promoted by La(OTf)3 — The analysis of non-integer pH/rate profiles resulting from changes in metal ion speciation

2005 ◽  
Vol 83 (9) ◽  
pp. 1268-1276 ◽  
Author(s):  
Graham TT Gibson ◽  
Alexei A Neverov ◽  
Allen Chun-Tien Teng ◽  
R S Brown
Keyword(s):  
Kinetic Data ◽  
Metal Ion ◽  
General Observation ◽  
Transient Complex ◽  
Phosphate Diester ◽  
Nitrophenyl Phosphate ◽  
Speciation Diagrams ◽  
Diphenyl Phosphate ◽  
The Individual ◽  
Phosphate Diesters

In a previous publication (A.A. Neverov and R.S. Brown. Inorg. Chem. 40, 3588 (2001)) we reported very effective catalysis of the methanolysis of some phosphate diesters (methyl p-nitrophenyl phosphate (1), bis(p-nitrophenyl) phosphate (2), and diphenyl phosphate (3)) promoted by La3+, and noted a general observation that the plots of logkcat vs. [Formula: see text]pH had non-integer gradients. In this report the origins of that behaviour are studied and analyzed through determination of the speciation of La3+(–OCH3)n, (La3+)2(–OCH3)m, (La3+)2:phosphate:(–OCH3)y forms in solution as a function of [Formula: see text]pH. Potentiometric titrations of solutions of La(OTf)3 in methanol at low (<1 × 10–4 mol/L) and high (>1 × 10–3 mol/L) concentration were analyzed through fits of the data to various models to provide speciation diagrams of the various La3+ forms in the absence of phosphate. Titrations of La3+ in the presence of diphenyl phosphate were also analyzed to provide speciation diagrams for phosphate bound forms. The kinetic data for the La3+ catalyzed methanolysis of 1 were analyzed through fitting the kinetic data at low and high [La3+] as a function of [Formula: see text]pH to a linear combination of the individual kinetic contributions of each species. Overall the data are best analyzed in the low [La3+] domain as resulting from methoxide attack on a transient complex of phosphate bound to La3+(–OCH3)0,1. In the high [La3+] domain the data fit two kinetically equivalent processes involving either a spontaneous decomposition of (La3+)2:1–:(–OCH3)2,3,4,5 or external methoxide attack on (La3+)2:1–:(–OCH3)1,2,3,4. Key words: lanthanides, phosphate diester, methanolysis, kinetics, speciation, metal ion catalysis of methanolysis, DNA model methanolysis.

Dissolved Organic Phosphorus Compounds: Do They Satisfy Planktonic Phosphate Demand in Summer?

1986 ◽  
Vol 43 (2) ◽  
pp. 343-350 ◽  
Author(s):  
Robert T. Heath
Keyword(s):  
Uptake Rate ◽  
Phosphate Uptake ◽  
Organic Phosphorus ◽  
Open Water ◽  
Eutrophic Lake ◽  
Phosphorus Compounds ◽  
Savannah River ◽  
Dissolved Organic Phosphorus ◽  
Western Basin ◽  
Nitrophenyl Phosphate

The rate of release of phosphate from dissolved organic phosphorus (DOP) compounds generally accounted for <1% of the phosphate uptake rate by seston in the open water of five diverse freshwater systems in summer. Surface water samples were taken during July and August 1984 from a eutrophic lake (East Twin Lake, OH), an acid bog lake (Triangle Bog Lake, OH), a freshwater estuarine marsh that empties into the western basin of Lake Erie (Old Woman Creek, OH), and two large mainstem reservoirs on the Savannah River (R. B. Russel Reservoir and Clarks Hill Lake, GA). In each of these, phosphatase hydrolysable phosphomonoesters (PME) often were the major fraction of DOP; phosphate release from photosensitive DOP was not detected in any of these systems at this time. The rate of release of phosphate from PME was calculated from Michaelis–Menten kinetics, and phosphatase activity was estimated spectrophotometrically using p-nitrophenyl phosphate as a model substrate. Radiometric analysis of the rate of phosphate uptake by seston showed that phosphate was sorbed to seston by at least two different processes. The total uptake rate by all uptake processes exhibited an apparent first-order dependence on the concentration of available phosphate. Typically, the velocity of uptake was 1–10 nmol∙L−1∙min−1, and the velocity of release from PME was 0.01–0.06 nmol∙L−1∙min−1.

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