Seasonal distribution of vitamin B12 in Lake Kinneret

Cavari, Benzion; Grossowicz, N.

doi:10.1128/aem.34.2.120-124.1977

Cited by 11 publications

(4 citation statements)

References 16 publications

(12 reference statements)

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“…Our metagenomic analysis of high latitude samples implies that Thaumarchaeota were responsible for vitamin B 12 production in this experiment, and implies that thaumarchaeotal productivity may be limited by cobalt concentrations. Importantly, vitamin B 12 was shown to influence phytoplankton growth and community composition in samples taken from the subarctic Gulf of Alaska ( Koch et al , 2011 ), which is consistent with controls on phytoplankton growth by vitamin B 12 in freshwater environments as well ( Daisley, 1969 ; Cavari and Grossowicz, 1977 ). Together, these results provide early evidence that cobalamin production by Thaumarchaeota may directly influence phytoplanktonic communities in polar surface waters, freshwater and possibly in marine surface waters via mixing with ocean water column vitamin pools.…”

Section: Discussionsupporting

confidence: 52%

Aquatic metagenomes implicate Thaumarchaeota in global cobalamin production

et al. 2014

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Cobalamin (vitamin B12) is a complex metabolite and essential cofactor required by many branches of life, including most eukaryotic phytoplankton. Algae and other cobalamin auxotrophs rely on environmental cobalamin supplied from a relatively small set of cobalamin-producing prokaryotic taxa. Although several Bacteria have been implicated in cobalamin biosynthesis and associated with algal symbiosis, the involvement of Archaea in cobalamin production is poorly understood, especially with respect to the Thaumarchaeota. Based on the detection of cobalamin synthesis genes in available thaumarchaeotal genomes, we hypothesized that Thaumarchaeota, which are ubiquitous and abundant in aquatic environments, have an important role in cobalamin biosynthesis within global aquatic ecosystems. To test this hypothesis, we examined cobalamin synthesis genes across sequenced thaumarchaeotal genomes and 430 metagenomes from a diverse range of marine, freshwater and hypersaline environments. Our analysis demonstrates that all available thaumarchaeotal genomes possess cobalamin synthesis genes, predominantly from the anaerobic pathway, suggesting widespread genetic capacity for cobalamin synthesis. Furthermore, although bacterial cobalamin genes dominated most surface marine metagenomes, thaumarchaeotal cobalamin genes dominated metagenomes from polar marine environments, increased with depth in marine water columns, and displayed seasonality, with increased winter abundance observed in time-series datasets (e.g., L4 surface water in the English Channel). Our results also suggest niche partitioning between thaumarchaeotal and cyanobacterial ribosomal and cobalamin synthesis genes across all metagenomic datasets analyzed. These results provide strong evidence for specific biogeographical distributions of thaumarchaeotal cobalamin genes, expanding our understanding of the global biogeochemical roles played by Thaumarchaeota in aquatic environments.

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Section: Discussionsupporting

confidence: 52%

Aquatic metagenomes implicate Thaumarchaeota in global cobalamin production

et al. 2014

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“…3C). Freshwater bodies typically have B 12 concentrations in the range from 0.11 nM to below the level of detection (<0.1 pM) (37, 38, 52–55), suggesting that high levels of BtuB may help facilitate import. Importantly, the conserved metE and btuB riboswitches are sensitive to B 12 in physiologically relevant ranges ( K 1/2 = 0.062 nM and 0.19 nM, respectively), and their different sensitivities suggest that metE translation would be downregulated before shutting off the btuB importer.…”

Section: Discussionmentioning

confidence: 99%

Absolute Measurements of mRNA Translation in Caulobacter crescentus Reveal Important Fitness Costs of Vitamin B ₁₂ Scavenging

2019

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Caulobacter crescentus is a model for the bacterial cell cycle which culminates in asymmetric cell division, yet little is known about the absolute levels of protein synthesis of the cellular parts needed to complete the cell cycle. Here we utilize ribosome profiling to provide absolute measurements of mRNA translation in C. crescentus, providing an important resource with quantitative genome-wide measurements of protein output across individual genes. Analysis of protein synthesis rates revealed ∼4.5% of cellular protein synthesis is for genes related to vitamin B12 import (btuB) and B12-independent methionine biosynthesis (metE) when grown in common growth media lacking B12. While its facultative B12 lifestyle provides a fitness advantage in the absence of B12, we find that it provides a fitness disadvantage of the cells in the presence of B12, potentially explaining why many Caulobacter species have lost the metE gene and become obligates for B12. IMPORTANCE Caulobacter crescentus is a model system of the bacterial cell cycle culminating in asymmetric cell division, with each daughter cell inheriting a distinct set of proteins. While a genetic network of master transcription factors coordinates the cell cycle timing of transcription for nearly 20% of Caulobacter genes, we lack knowledge of how many of each protein “part” encoded in the genome are synthesized. Therefore, to determine the absolute production rates across the genome, we performed ribosome profiling, providing, for the first time, a quantitative resource with measurements of each protein “part” needed to generate daughter cells. This resource furthers the goal of a systems-level understanding of the genetic network controlling asymmetric cell division. To highlight the utility of this data set, we probe the protein synthesis cost of a B12 utilization pathway and provide new insights into Caulobacter’s adaptation to its natural environments.

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“…Absorption of the micronutrients such as vitamins by microalgal groups is highly challenging, as they are present in extremely low concentrations in the sea and fresh water. The amount of vitamin B 12 in seawater ranges between 0 and 70 ng/l [ 50 – 52 ] followed by fresh water having little higher levels [ 53 , 54 ]. However, these levels of vitamer’s are still very low in order to support vitamin B 12 -dependent microalgal growth as the microalgae require a minimum of 10 ng/l concentration of cobalamin to grow [ 36 , 55 ].…”

Section: Introductionmentioning

confidence: 99%

A promising approach to enhance microalgae productivity by exogenous supply of vitamins

2017

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In order to reduce the consumption of traditional fossil fuels and their impact on the environment, strategies to mitigate greenhouse gas emissions especially carbon dioxide needs exploration. Microalgae-based biofuels can be the best-fit plant based feed-stocks for diminishing a majority of the Universe’s energy problems. Interestingly, the eukaryotic microalgae aid in fixation of almost 50% of the global carbon in the environment. Thus, determination of parameters that will enhance microalgal growth and productivity is crucial, if they are to be used as future renewable energy sources. A large percentage of phytoplankton species are auxotroph for one or more vitamins. These species, in turn, are also dependent upon the vitamin biosynthetic pathways for processing of these vitamins. The present study serves as a base to discuss the prevalence of vitamin auxotrophy in microalgae and the methods of its acquirement from external sources such as heterotrophic bacteria. The next section of the paper sheds light on possible species-specific symbiotic interactions among microalgae and bacteria. Lastly is the discussion on how heterotrophic bacteria can act as a vitamin prototroph for an explicit microalgal vitamin auxotroph. The overall focus is placed upon harnessing these symbiotic interactions with intentions to obtain enhancements in microalgal biomass, lipid productivity, and flocculation rates. Moreover, the growth and distribution of a microalgal cell that thrives on a specific vitamin is perhaps met by growing it with the bacterial communities that nourish it. Thus, possibly by ecologically engineering a potential species-specific microalgal–bacterial consortium, it could tremendously contribute to the acceleration of photosynthetic activity, microalgal productivity, exchange of primary metabolites and other biogeochemical nutrients within the mini ecosystem.

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Seasonal distribution of vitamin B12 in Lake Kinneret

Cited by 11 publications

References 16 publications

Aquatic metagenomes implicate Thaumarchaeota in global cobalamin production

Aquatic metagenomes implicate Thaumarchaeota in global cobalamin production

Absolute Measurements of mRNA Translation in Caulobacter crescentus Reveal Important Fitness Costs of Vitamin B ₁₂ Scavenging

A promising approach to enhance microalgae productivity by exogenous supply of vitamins

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Seasonal distribution of vitamin B12 in Lake Kinneret

Cited by 11 publications

References 16 publications

Aquatic metagenomes implicate Thaumarchaeota in global cobalamin production

Aquatic metagenomes implicate Thaumarchaeota in global cobalamin production

Absolute Measurements of mRNA Translation in Caulobacter crescentus Reveal Important Fitness Costs of Vitamin B 12 Scavenging

A promising approach to enhance microalgae productivity by exogenous supply of vitamins

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Product

Resources

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Absolute Measurements of mRNA Translation in Caulobacter crescentus Reveal Important Fitness Costs of Vitamin B ₁₂ Scavenging