The combined relationship of temperature and molybdenum concentration to nitrogen fixation byAnabaena cylindrica

Jacobs, R.D.; Lind, Owen T.

doi:10.1007/bf02010618

Cited by 8 publications

(5 citation statements)

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“…However, both Chl a concentrations and N 2 -fixation rates required time periods of weeks to decline (Fig. 1), consistent with previous studies (Fay and Vasconcelos 1974;Jacob and Lind 1977). This lag time suggests HC may maintain adaptive strategies, such as stores of cellular Mo, that allow them to survive on low Mo availability for weeks after Mo concentrations are depleted (see below).…”

Section: Discussionsupporting

confidence: 88%

“…This lag time suggests HC may maintain adaptive strategies, such as stores of cellular Mo, that allow them to survive on low Mo availability for weeks after Mo concentrations are depleted (see below). Our data indicate that 10 nmol Mo L 21 is sufficient for maximal N 2 -fixation in the two Nostoc species studied, as previously observed for other HC such as A. cylindrica (Jacob and Lind 1977) and A. variabilis ATCC 29413 (Zerkle et al 2006). The maximal N 2 -fixation rates measured in this study (, 8 nmol C 2 H 4 mg Chl a 21 h 21 ) are comparable to N 2 -fixation rates of A. variabilis ATCC 29413 and A. cylindrica (Attridge and Rowell 1997;Rowell et al 1998).…”

Section: Discussionsupporting

confidence: 88%

“…A. cylindrica and certain other diazotrophic cyanobacteria isolate nitrogenase in specialized cells called heterocysts to prevent its irreversible destruction by photosynthetically derived oxygen (O 2 ) and O 2 -derived radicals (Fay 1992). Pigment content and nitrogenase activity of A. cylindrica declined after 7-10 d of growth in Mo-deficient media (, 5 nmol L 21 ;Fay and Vasconcelos [1974]; Jacob and Lind [1977]). These physiological changes were reversed by addition of Mo to the growth media (Ter Steeg et al 1986).…”

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confidence: 99%

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Molybdenum—nitrogen co‐limitation in freshwater and coastal heterocystous cyanobacteria

Glass

Wolfe-Simon

Elser

et al. 2010

Limnology & Oceanography

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Molybdenum (Mo) is essential for the biological assimilation of inorganic nitrogen (N). We compared Mo requirements for N2‐fixation in two species of filamentous heterocystous cyanobacteria (HC) to test the hypothesis that coastal HC require higher Mo concentrations than freshwater HC. This expectation follows from the fact that Mo is more concentrated in seawater (~ 105 nmol L−1) than in most freshwaters (< 20 nmol L−1). Contrary to this hypothesis, we found that both strains maintained N2‐fixation for 30 d at 10 nmol L−1. Mo concentrations < 1 nmol L−1 induced N‐limitation in both species, as indicated by increased C:N ratios and decreased nitrogenase expression and activity. This response took time to induce, likely due to high‐affinity molybdate uptake by both species. Measurable N2‐fixation persisted in the coastal strain (Nostoc sp. CCMP 2511) for at most 12 d; 3 d were required for chlorophyll a concentrations to fall below those of Mo‐replete cultures. An additional 7 d and 11 d, respectively, were required for N2‐fixation rates and chlorophyll levels to decline in Mo‐limited freshwater cultures (Nostoc sp. PCC 7120). When Mo was high (> 1 µmol L−1), the freshwater strain exhibited considerable Mo storage (> 100 µmol mol−1 Mo: C) whereas cellular Mo remained < 10 µmol mol−1 Mo:C in the coastal strain. The high Mo content and extended time required for N2‐fixation to decrease in the freshwater strain could be due to expression of the gene mop, which encodes a putative molybdate‐storage protein. This study suggests the importance of Mo storage in freshwater HC.

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Section: Discussionsupporting

confidence: 88%

Section: Discussionsupporting

confidence: 88%

mentioning

confidence: 99%

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Molybdenum—nitrogen co‐limitation in freshwater and coastal heterocystous cyanobacteria

Glass

Wolfe-Simon

Elser

et al. 2010

Limnology & Oceanography

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“…Culturing experiments with modern strains of diazotrophic (nitrogen-fixing) cyanobacteria generally indicate that rates of nitrogen fixation and overall growth become impacted by Mo availability once concentrations fall to within the ∼1-10-nM range (45)(46)(47)(48)(49). Some strains seem to show resilience to Mo scarcity until concentrations fall below ∼5 nM (48), but in general there seems to be a sharp change in overall growth rates, cell-specific nitrogen fixation rates, and stoichiometric growth status within the 1-10-nM range.…”

Section: Marine Euxinia: Global Effects Of Regional Ocean Chemistrymentioning

confidence: 99%

Proterozoic ocean redox and biogeochemical stasis

Reinhard

Planavsky

Robbins

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

442

407

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The partial pressure of oxygen in Earth's atmosphere has increased dramatically through time, and this increase is thought to have occurred in two rapid steps at both ends of the Proterozoic Eon (∼2.5-0.543 Ga). However, the trajectory and mechanisms of Earth's oxygenation are still poorly constrained, and little is known regarding attendant changes in ocean ventilation and seafloor redox. We have a particularly poor understanding of ocean chemistry during the mid-Proterozoic (∼1.8-0.8 Ga). Given the coupling between redoxsensitive trace element cycles and planktonic productivity, various models for mid-Proterozoic ocean chemistry imply different effects on the biogeochemical cycling of major and trace nutrients, with potential ecological constraints on emerging eukaryotic life. Here, we exploit the differing redox behavior of molybdenum and chromium to provide constraints on seafloor redox evolution by coupling a large database of sedimentary metal enrichments to a mass balance model that includes spatially variant metal burial rates. We find that the metal enrichment record implies a Proterozoic deep ocean characterized by pervasive anoxia relative to the Phanerozoic (at least ∼30-40% of modern seafloor area) but a relatively small extent of euxinic (anoxic and sulfidic) seafloor (less than ∼1-10% of modern seafloor area). Our model suggests that the oceanic Mo reservoir is extremely sensitive to perturbations in the extent of sulfidic seafloor and that the record of Mo and chromium enrichments through time is consistent with the possibility of a Mo-N colimited marine biosphere during many periods of Earth's history.paleoceanography | geobiology

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“…Since Bortels' early studies, Nostoc / Anabaena and Azotobacter strains have been model organisms for the study of Mo requirements for N 2 fixation. Subsequent studies showed that Anabaena had optimal growth at dissolved Mo concentrations in the range of 50–2000 nM (Wolfe, 1954 ; Jacob and Lind, 1977 ; ter Steeg et al, 1986 ; Attridge and Rowell, 1997 ) and that Mo limitation of N 2 fixation occurred at 1–5 nM Mo (Fay and Vasconcelos, 1974 ; Attridge and Rowell, 1997 ; Zerkle et al, 2006 ; Glass et al, 2010 ). The onset of Mo limitation requires several transfers to ensue, likely due to the expression of high-affinity ModABC MoO 2− 4 uptake systems, which are widely distributed in bacteria and archaea (Self et al, 2001 ; Zhang and Gladyshev, 2008 ) and have been characterized in Nostoc/Anabaena (Thiel et al, 2002 ; Zahalak et al, 2004 ).…”

Section: Pure Culture Studiesmentioning

confidence: 99%

Molybdenum limitation of microbial nitrogen assimilation in aquatic ecosystems and pure cultures

Glass¹,

Axler²,

Chandra³

et al. 2012

Front. Microbio.

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Molybdenum (Mo) is an essential micronutrient for biological assimilation of nitrogen gas and nitrate because it is present in the cofactors of nitrogenase and nitrate reductase enzymes. Although Mo is the most abundant transition metal in seawater (107 nM), it is present in low concentrations in most freshwaters, typically <20 nM. In 1960, it was discovered that primary productivity was limited by Mo scarcity (2–4 nM) in Castle Lake, a small, meso-oligotrophic lake in northern California. Follow up studies demonstrated that Mo also limited primary productivity in lakes in New Zealand, Alaska, and the Sierra Nevada. Research in the 1970s and 1980s showed that Mo limited primary productivity and nitrate uptake in Castle Lake only during periods of the growing season when nitrate concentrations were relatively high because ammonium assimilation does not require Mo. In the years since, research has shifted to investigate whether Mo limitation also occurs in marine and soil environments. Here we review studies of Mo limitation of nitrogen assimilation in natural microbial communities and pure cultures. We also summarize new data showing that the simultaneous addition of Mo and nitrate causes increased activity of proteins involved in nitrogen assimilation in the hypolimnion of Castle Lake when ammonium is scarce. Furthermore, we suggest that meter-scale Mo and oxygen depth profiles from Castle Lake are consistent with the hypothesis that nitrogen-fixing cyanobacteria in freshwater periphyton communities have higher Mo requirements than other microbial communities. Finally, we present topics for future research related to Mo bioavailability through time and with changing oxidation state.

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The combined relationship of temperature and molybdenum concentration to nitrogen fixation byAnabaena cylindrica

Cited by 8 publications

References 9 publications

Molybdenum—nitrogen co‐limitation in freshwater and coastal heterocystous cyanobacteria

Molybdenum—nitrogen co‐limitation in freshwater and coastal heterocystous cyanobacteria

Proterozoic ocean redox and biogeochemical stasis

Molybdenum limitation of microbial nitrogen assimilation in aquatic ecosystems and pure cultures

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