Minimum Cyanocobalamin Requirements of Some Marine Centric Diatoms1

Guilllard, Robert R. L.; Cassie, Vivienne

doi:10.4319/lo.1963.8.2.0161

Cited by 38 publications

(14 citation statements)

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“…When the minimal cell quota is expressed as the number of vitamin B12 molecules pm-3 cell volume, Cladophora has about 4 molecules prnh3. This value is within the range of 2-18 molecules pm-3 reported as a minimal cell concentration for both bacteria and unicellular algae (Droop 19 5 7;Guillard and Cassie 1963;Bradbeer 197 1).…”

Section: Discussionsupporting

confidence: 49%

Dependence of photosynthesis and vitamin B12 uptake on cellular vitamin B12 concentration in the multicellular alga Cladophora glomerata (Chlorophyta)

Hoflmann

1990

Limnol. Oceanogr.

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The influence of vitamin Blz on the growth potential of Cfadophora glomerata (L.) Kiitz. was investigated by quantifying the following responses to cellular vitamin B12 concentrations: yield, photosynthetic rate, and vitamin B,, uptake rate. Yield was expressed as dry weight harvested after a 28-d growth period; photosynthetic rate was estimated by the 14C technique; vitamin uptake rates were determined with 3H-labeled vitamin B12, and cellular vitamin BL2 concentration was estimated by bioassay. Functional dependence of these responses on cellular vitamin B,, concentration was best described by the Droop cell-quota model. The critical concentration, defined as lhe minimal cellular vitamin B,, concentration needed for a maximal response, was estimated as ihe concentration range that resulted in a response that was 75-85% of the maximum. Responses consistently resulted in a predicted critical concentration range of 0.3-0.5 ng B12 (mg dry wt)-'. This is interpreted as a range of cellular vitamin B,2 concentration below which significant limitation of the growth potential of Cladophora occurs and above which it does not. This critical concentration range can be used to indicate vitamin BLZ limitation in nature. The physiological parameters describing the Cladophora response curves are similar to those of other algae 1 hat require vitamin IB,,.

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Section: Discussionsupporting

confidence: 49%

Dependence of photosynthesis and vitamin B12 uptake on cellular vitamin B12 concentration in the multicellular alga Cladophora glomerata (Chlorophyta)

Hoflmann

1990

Limnol. Oceanogr.

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“…The cobalt ligands measured in seawater may be apo-cobalamin (B 12 ) or its degradation products. Vitamin B 12 has been explored as a potentially limiting micronutrient for marine phytoplankton (Guillard and Cassie 1963;Swift 1992). Yet calculations of B 12 quotas and cobalt quotas in Synechococcus suggest that B 12 is only a minor component of the cobalt requirement (ϳ4%, Sunda and Huntsman 1995;Wilhelm and Trick 1995).…”

Section: Resultsmentioning

confidence: 99%

Cobalt limitation and uptake in Prochlorococcus

Saito

Moffett

Chisholm

et al. 2002

Limnology & Oceanography

234

191

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Processes that enable marine phytoplankton to acquire trace metals are fundamental to our understanding of primary productivity and global carbon biogeochemical cycling. Here we show that the abundant marine cyanobacterium, Prochlorococcus strain MED4-Ax, has an absolute cobalt requirement and that zinc cannot substitute for cobalt in the growth medium, as is the case in some other phytoplankton species. When resuspended into fresh medium, uptake of cobalt into the cell occurs as free cobalt (Co 2ϩ ). In contrast, cultures augmented with conditioned medium assimilated cobalt significantly faster than those in fresh medium, leading to the hypothesis that Prochlorococcus produced organic cobalt ligands in the conditioned medium. This work suggests that the availability of cobalt might influence the composition of phytoplankton assemblages in the open ocean.Analytical methods for measuring trace metals in seawater have improved significantly over the past two decades, contributing to important advances in our understanding of oceanic biogeochemistry. The findings that major regions of the oceans are iron limited (Martin and Fitzwater 1988) and that iron can have nutrient-like profiles (Martin and Gordon 1988) have illustrated the importance of trace metals in global carbon cycling. The development of electrochemical iron speciation methods (Rue and Bruland 1995;Wu and Luther 1995) has led to the idea that biogenic ligands may in fact be controlling the residence time of iron in the surface ocean (Johnson et al. 1997). With the discovery that zinc, cobalt, and cadmium can each occupy the active site of carbonic anhydrase enzymes in phytoplankton (Price and Morel 1990;Morel et al. 1994;Roberts et al. 1997) and that potentially growth limiting levels of Co and Zn have been measured in oceanic surface waters (Martin et al. 1989; Sunda and Hunts-

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“…Early workers demonstrated a B 12 requirement in many marine algae and hypothesized that B 12 could influence marine primary production and phytoplankton species composition (Droop 1957;Guillard and Cassie 1963;Swift 1981). A recent literature review of 326 algal species found more than half to be B 12 auxotrophs (Croft et al 2005), similar to earlier estimates that 70% of phytoplankton species require the vitamin (Swift 1981).…”

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confidence: 99%

Vitamin B₁₂ and iron colimitation of phytoplankton growth in the Ross Sea

Bertrand

Saito

Rose

et al. 2007

Limnology & Oceanography

207

241

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Primary production in the Ross Sea, one of the most productive areas in the Southern Ocean, has previously been shown to be seasonally limited by iron. In two of three bottle incubation experiments conducted in the austral summer, significantly higher chlorophyll a (Chl a) concentrations were measured upon the addition of iron and B 12 , relative to iron additions alone. Initial bacterial abundances were significantly lower in the two experiments that showed phytoplankton stimulation upon addition of B 12 and iron relative to the experiment that did not show this stimulation. This is consistent with the hypothesis that the bacteria and archaea in the upper water column are an important source of B 12 to marine phytoplankton. The addition of iron alone increased the growth of Phaeocystis antarctica relative to diatoms, whereas in an experiment where iron and B 12 stimulated total phytoplankton growth, the diatom Pseudonitzschia subcurvata went from comprising approximately 70% of the phytoplankton community to over 90%. Cobalt additions, with and without iron, did not alter Chl a biomass relative to controls and iron additions alone in the Ross Sea. Iron and vitamin B 12 plus iron treatments caused reductions in the DMSP (dimethyl sulfoniopropionate) : Chl a ratio relative to the control and B 12 treatments, consistent with the notion of an antioxidant function for DMSP. These results demonstrate the importance of a vitamin to phytoplankton growth and community composition in the marine environment.The nutritional controls on marine phytoplankton growth have important implications for the regulation of the global carbon cycle. Nitrogen and iron are thought to be the dominant controllers of phytoplankton growth in the oceans, and hence the discovery of a vitamin such as B 12 having an influence on marine primary productivity would be a finding of significance. The limited information about the biogeochemical cycle of this vitamin suggests that it may be in limiting quantities in seawater. B 12 is a biologically produced cobalt-containing organometallic molecule, and only select bacteria and archaea possess the capability for B 12 biosynthesis. As a result, all eukaryotic organisms, from eukaryotic phytoplankton to humans, must either acquire B 12 from the environment or possess an alternate biochemistry that does not require the vitamin. Removal of B 12 from the water column has never been directly quantified but likely includes photodegradation 1 Corresponding author (mak@whoi.edu). 2 Coauthors. AcknowledgmentsWe thank Peter Sedwick for allowing us to utilize his tracemetal-clean fish sampling system and David Hutchins for allowing us to work in his laboratory van and for helpful discussions. We also thank Bettina Sohst and Carol Pollard for nutrient analyses and Tyler Goepfert for help in Phaeocystis antarctica culture studies, and Sheila Clifford for comments on the manuscript. Special thanks to the captain, crew, and Raytheon marine and scientific technical staff of the RV N. B. Palmer. Thanks also to ...

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Minimum Cyanocobalamin Requirements of Some Marine Centric Diatoms1

Cited by 38 publications

References 0 publications

Dependence of photosynthesis and vitamin B12 uptake on cellular vitamin B12 concentration in the multicellular alga Cladophora glomerata (Chlorophyta)

Dependence of photosynthesis and vitamin B12 uptake on cellular vitamin B12 concentration in the multicellular alga Cladophora glomerata (Chlorophyta)

Cobalt limitation and uptake in Prochlorococcus

Vitamin B₁₂ and iron colimitation of phytoplankton growth in the Ross Sea

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Minimum Cyanocobalamin Requirements of Some Marine Centric Diatoms1

Cited by 38 publications

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Dependence of photosynthesis and vitamin B12 uptake on cellular vitamin B12 concentration in the multicellular alga Cladophora glomerata (Chlorophyta)

Dependence of photosynthesis and vitamin B12 uptake on cellular vitamin B12 concentration in the multicellular alga Cladophora glomerata (Chlorophyta)

Cobalt limitation and uptake in Prochlorococcus

Vitamin B12 and iron colimitation of phytoplankton growth in the Ross Sea

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Vitamin B₁₂ and iron colimitation of phytoplankton growth in the Ross Sea