Glen Wheeler

Marine Biological Association of the UK | MBA · Department of Marine Biology

Coccolithophores are the most abundant calcifying organisms in modern oceans and are important primary producers in many marine ecosystems. Their ability to generate a cellular covering of calcium carbonate plates (coccoliths) plays a major role in marine biogeochemistry and the global carbon cycle. Coccolithophores also play an important role in s...

Coccolithophores are a group of unicellular marine algae that shape global geochemical cycles via the production of calcium carbonate crystals. Interestingly, different life-cycle phases of the same coccolithophore species produce very different calcitic scales, called coccoliths. In the widely studied diploid phase, the crystals have anisotropic a...

Coccolithophores are an important group of calcifying marine phytoplankton. Although coccolithophores are not silicified, some species exhibit a requirement for Si in the calcification process. These species also possess a novel protein (SITL) that resembles the SIT family of Si transporters found in diatoms. However, the nature of Si transport in...

Diatoms are a group of microalgae that are important primary producers in a range of open ocean, freshwater, and intertidal environments. The latter can experience substantial long- and short-term variability in temperature, from seasonal variations to rapid temperature shifts caused by tidal immersion and emersion. As temperature is a major determ...

Significance Coccolithophore calcification is a major ocean biogeochemical process. While this process is likely to be sensitive to acidification-driven changes in ocean carbonate chemistry, incomplete understanding of the underlying mechanisms and constraints is a major bottleneck in predicting ocean acidification effects on calcification. We repo...

Diatoms represent one of the most successful groups of marine phytoplankton and are major contributors to ocean biogeochemical cycling. They have colonized marine, freshwater and ice environments and inhabit all regions of the World’s oceans, from poles to tropics. Their success is underpinned by a remarkable ability to regulate their growth and me...

Coccolithophores produce the bulk of ocean biogenic calcium carbonate but this process is predicted to be negatively affected by future ocean acidification scenarios. Since coccolithophores calcify intracellularly, the mechanisms through which changes in seawater carbonate chemistry affect calcification remain unclear. Here we show that voltage-gat...

The impact of selective predation of weaker individuals on the general health of prey populations is well-established in animal ecology. Analogous processes have not been considered at microbial scales despite the ubiquity of microbe-microbe interactions, such as parasitism. Here we present insights into the biotic interactions between a widespread...

Coccolithophores are globally important marine calcifying phytoplankton that utilize a haplo-diplontic life cycle. The haplo-diplontic life cycle allows coccolithophores to divide in both life cycle phases and potentially expands coccolithophore niche volume. Research has, however, to date largely overlooked the life cycle of coccolithophores and h...

The movement of ciliary membrane proteins is directed by transient interactions with intraflagellar transport (IFT) trains. The green alga Chlamydomonas has adapted this process for gliding motility, using retrograde IFT motors to move adhesive glycoproteins in the flagella membrane. Ca ²⁺ signalling contributes directly to the gliding process, alt...

Diatoms are globally important phytoplankton that dominate coastal and polar‐ice assemblages. These environments exhibit substantial changes in salinity over dynamic spatiotemporal regimes. Rapid sensory systems are vital to mitigate the harmful consequences of osmotic stress. Population‐based analyses have suggested that Ca ²⁺ signalling is involv...

The development of calcification by the coccolithophores had a profound impact on ocean carbon cycling, but the evolutionary steps leading to the formation of these complex biomineralized structures are not clear. Heterococcoliths consisting of intricately shaped calcite crystals are formed intracellularly by the diploid life cycle phase. Holococco...

Diatoms are a diverse and globally important phytoplankton group, responsible for an estimated 20% of carbon fixation on Earth. They frequently form spatially extensive phytoplankton blooms, responding rapidly to increased availability of nutrients, including phosphorus (P) and nitrogen (N). Although it is well established that diatoms are common f...

The evolution of Na+-selective four-domain voltage-gated channels (4D-Navs) in animals allowed rapid Na+-dependent electrical excitability, and enabled the development of sophisticated systems for rapid and long-range signalling. Whilst bacteria encode single-domain Na+-selective voltage-gated channels (BacNav), they typically exhibit much slower k...

The movement of ciliary membrane proteins is directed by transient interactions with intraflagellar transport (IFT) trains. The green alga Chlamydomonas has adapted this process for gliding motility, using IFT to move adhesive glycoproteins (FMG-1B) in the flagella membrane. Although Ca2+ signalling contributes directly to the gliding process, unce...

p>Coccolithophores represent a major component of the marine phytoplankton and contribute to the bulk of biogenic calcite formation on Earth. These unicellular protists produce minute calcite scales (coccoliths) within the cell, which are secreted to the cell surface. Individual coccoliths and their arrangements on the cell surface display a wide r...

Coccolithophores represent a major component of the marine phytoplankton and contribute to the bulk of biogenic calcite formation on Earth. These unicellular protists produce minute calcite scales (coccoliths) within the cell, which are secreted to the cell surface. Individual coccoliths and their arrangements on the cell surface display a wide ran...

Coccolithophores are important contributors to global calcium carbonate through their species-specific production of calcite coccoliths. Nannofossil coccolith calcite remains an important tool for paleoreconstructions through geochemical analysis of isotopic and trace element incorporation including Sr, which is a potential indicator of past surfac...

Coccolithophores are calcifying microalgae that carry characteristic calcite platelets (coccoliths) on their surfaces. Most coccolithophore species exhibit diploid and haploid life cycle stages, each adjusted to different environmental conditions. The diploid life cycle stage of the coccolithophore C. braarudii is heavily calcifying with calcificat...

Coccolithophores are globally important marine calcifying phytoplankton that utilize a haplo-diplontic life cycle. The haplo-diplontic life cycle allows coccolithophores to divide in both life cycle phases, and has been proposed to allow coccolithophores to expand their niche space. To-date research has however largely overlooked the life cycle of...

Key to the ecological prominence of fungi is their distinctive cell biology, our understanding of which has been principally based on dikaryan hyphal and yeast forms. The early-diverging Chytridiomycota (chytrids) are ecologically important and a significant component of fungal diversity, yet their cell biology remains poorly understood. Unlike dik...

Diatoms are a diverse and globally important phytoplankton group, responsible for an estimated 20% of carbon fixation on Earth. They frequently form spatially extensive phytoplankton blooms, responding rapidly to increased availability of nutrients including phosphorus and nitrogen. Although it is well established that diatoms are common first-resp...

The evolution of Na ⁺ -selective four-domain voltage-gated channels (4D-Na v s) in animals allowed rapid Na ⁺ -dependent electrical excitability, and enabled the development of sophisticated systems for rapid and long-range signalling. Whilst bacteria encode single-domain Na ⁺ -selective voltage-gated channels (BacNa v ), they typically exhibit muc...

Fungi are major components of the Earth's biosphere, sustaining many critical ecosystem processes. Key to fungal prominence is their characteristic cell biology, our understanding of which has been principally based on 'higher' dikaryan hyphal and yeast forms. The early-diverging Chytridiomycota (chytrids) are ecologically important and a significa...

p> Rapid Na ⁺ /Ca ²⁺ -based action potentials govern essential cellular functions in eukaryotes, from the motile responses of unicellular protists, such as Paramecium [1, 2], to complex animal neuromuscular activity [3]. A key innovation underpinning this fundamental signaling process has been the evolution of four-domain volt...

Fig. S1 Images of internal malformed coccoliths. Fig. S2 Images of silicon (Si)‐depleted cultures. Fig. S3 Photosynthetic efficiency following disruption of calcification. Fig. S4 Time‐lapse microscopy of cell division in Coccolithus braarudii. Fig. S5 Cell division can occur in the absence of a coccosphere. Fig. S6 Malformed coccolith product...

Video S1 Cell division in Coccolithus braarudii.

Ostreococcus tauri, a picoeukaryotic alga that contributes significantly to primary production in oligotrophic waters, has a highly streamlined genome, lacking the genetic capacity to grow without the vitamins thiamine (B1) and cobalamin (B12). Here we demonstrate that the B12 and B1 auxotrophy of O. tauri can be alleviated by co-culturing with a h...

Coccolithophores are globally abundant marine microalgae characterized by their ability to form calcite platelets (coccoliths). The coccoliths are produced internally in a Golgi-derived vesicle. Mature coccoliths are extruded from the cell to form a protective covering on the cell surface, known as the coccosphere. Current evidence indicates that c...

Coccolithophores are globally distributed unicellular marine algae that are characterized by their covering of calcite coccoliths. Calcification by coccolithophores contributes significantly to global biogeochemical cycles. However, the physiological requirement for calcification remains poorly understood as non‐calcifying strains of some commonly...

Photosynthesis by marine diatoms plays a major role in the global carbon cycle, although the precise mechanisms of dissolved inorganic carbon (DIC) uptake remain unclear. A lack of direct measurements of carbonate chemistry at the cell surface has led to uncertainty over the underlying membrane transport processes and the role of external carbonic...

Like all organisms, the motile green alga Chlamydomonas has evolved an array of sensory mechanisms to enable it to detect and respond to an array of abiotic and biotic stimuli. It is clear that Ca²⁺-dependent signalling mechanisms are central to many responses in Chlamydomonas, from flagella function through to stress signalling and photosynthesis....

The production of calcium carbonate by coccolithophores (haptophytes) contributes significantly to global biogeochemical cycling. The recent identification of a silicifying haptophyte, Prymnesium neolepis, has provided new insight into the evolution of biomineralisation in this lineage. However, the cellular mechanisms of biomineralisation in both...

The work conducted by the US Department of Energy (DOE) Joint Genome Institute, a DOE Office of Science User Facility, was supported by the Office of Science of the US DOE under Contract DE-AC02-05CH11231 (to S.H.B., E.G., A.R.G., and J.W.S.). Other major research support was provided by NSF 0929558 (to S.H.B. and A.R.G.); National Oceanic and Atmo...

Video S1 A Ca2+ wave in Chlamydomonas reinhardtii induced by NaCl shock.

Fig. S1 Processing of data during Ca2+ imaging. Fig. S2 In vitro calibration of Oregon Green BAPTA dextran. Fig. S3 Spontaneous [Ca2+]cyt elevations induced by 10 mM external Ca2+. Fig. S4 [Ca2+]cyt elevations induced by hypo‐osmotic stress occur in the absence of contractile vacuole activity.

Coccolithophores occupy a special position within the marine phytoplankton because of their production of intricate calcite scales, or coccoliths. Coccolithophores are major contributors to global ocean calcification and long-term carbon fluxes. The intracellular production of coccoliths requires modifications to cellular ultrastructure and metabol...

Biosilicification (the formation of biological structures from silica) occurs in diverse eukaryotic lineages, plays a major role in global biogeochemical cycles and has significant biotechnological applications. Silicon (Si) uptake is crucial for biosilicification, yet the evolutionary history of the transporters involved remains poorly known. Rece...

Ca²⁺‐dependent signalling processes enable plants to perceive and respond to diverse environmental stressors, such as osmotic stress. A clear understanding of the role of spatiotemporal Ca²⁺ signalling in green algal lineages is necessary in order to understand how the Ca²⁺ signalling machinery has evolved in land plants. We used single‐cell imagin...

Coccolithophorids are enigmatic plankton that produce calcium carbonate coccoliths, which over geological time have buried atmospheric CO 2 into limestone, changing both the atmosphere and geology of the Earth. However , the role of coccoliths for the proliferation of these organisms remains unclear; suggestions include roles in anti-predation, enh...

Biomineralization by marine phytoplankton, such as the silicifying diatoms and calcifying coccolithophores, plays an important role in carbon and nutrient cycling in the oceans. Silicification and calcification are distinct cellular processes with no known common mechanisms. It is thought that coccolithophores are able to outcompete diatoms in Si-d...

Supplementary Figures 1-11 and Supplementary Tables 1-3.

Biosilicification (the formation of biological structures from silica) occurs in diverse eukaryotic lineages, plays a major role in global biogeochemical cycles, and has significant biotechnological applications. Silicon (Si) uptake is crucial for biosilicification, yet the evolutionary history of the transporters involved remains poorly known. Rec...

Coccolithophores are unicellular phytoplankton that are characterised by the presence intricately formed calcite scales (coccoliths) on their surfaces. Coccolith formation is an entirely intracellular process - crystal growth is confined within a Golgi-derived vesicle. A wide range of coccolith morphologies can be found amongst the different coccol...

Human activity causes ocean acidification (OA) though the dissolution of anthropogenically generated CO 2 into seawater, and eutrophication through the addition of inorganic nutrients. Eutrophication increases the phytoplankton biomass that can be supported during a bloom, and the resultant uptake of dissolved inorganic carbon during photosynthesis...

Identification of GULO and GLDH in marine microbial eukaryote transcriptomes. Data from the Marine Microbial Eukaryote Transcriptome Sequencing Project (MMETSP, http://marinemicroeukaryotes.org/) were analysed for the terminal enzymes in ascorbate biosynthesis. This dataset contains 679 transcriptomes from 320 different species. Sequence similarity...

Distribution of ascorbate biosynthetic genes in Archaeplastida transcriptomes. Rhodophyte transcriptomes from the Marine Microbial Eukaryote Transcriptome Sequencing Project (MMETSP) or Genbank (Chan et al., 2011, 2012) were examined for the presence of ascorbate biosynthesis genes. The rhodophytes transcriptomes all exhibit the pathway found in th...

Identification of VTC2 in marine microbial eukaryote transcriptomes. Data from the Marine Microbial Eukaryote Transcriptome Sequencing Project (MMETSP) was analysed for VTC2, encoding GDP-l-galactose phosphorylase, the first committed step in land plant ascorbate biosynthesis. Sequence similarity searches used a stringent cut off to avoid ambiguous...

Distribution of GULO and GLDH in opisthokont and apusomonad genomes. Genomes of the opisthokonts (including animals and fungi) were examined for the presence of GULO and GLDH. Strikethrough indicates non-functional pseudogenes. The absence of GULO is well documented in the known ascorbate auxotrophs such as haplorhine primates, guinea pigs, bats, t...

Genome resources used in this study. A list of the eukaryote genomes used to study the distribution of genes relating to ascorbate biosynthesis and metabolism. DOI: http://dx.doi.org/10.7554/eLife.06369.019

Ascorbic acid (vitamin C) is an enzyme co-factor in eukaryotes that also plays a critical role in protecting photosynthetic eukaryotes against damaging reactive oxygen species derived from the chloroplast. Many animal lineages, including primates, have become ascorbate auxotrophs due to the loss of the terminal enzyme in their biosynthetic pathway,...

European Phycological Congress 6, London 2015

A widespread and complex distribution of vitamin requirements exists over the entire tree of life, with many species having evolved vitamin dependence, both within and between different lineages. Vitamin availability has been proposed to drive selection for vitamin dependence, in a process that links an organism's metabolism to the environment, but...

A widespread and complex distribution of vitamin requirements exists over the entire tree of life, with many species having evolved vitamin dependence, both within and between different lineages. Vitamin availability has been proposed to drive selection for vitamin dependence, in a process that links an organism's metabolism to the environment, but...

Current sampling of genomic sequence data from eukaryotes is relatively poor, biased, and inadequate to address important questions about their biology, evolution, and ecology; this Community Page describes a resource of 700 transcriptomes from marine microbial eukaryotes to help understand their role in the world's oceans.

Intraflagellar transport (IFT) underpins many of the important cellular roles of cilia and flagella in signaling and motility [1-4]. The microtubule motors kinesin-2 and cytoplasmic dynein 1b drive IFT particles (protein complexes carrying ciliary component proteins) along the axoneme to facilitate the assembly and maintenance of cilia. IFT is regu...

Summary � Coccolithophores are important calcifying phytoplankton predicted to be impacted by changes in ocean carbonate chemistry caused by the absorption of anthropogenic CO2. However, it is difficult to disentangle the effects of the simultaneously changing carbonate system parameters (CO2, bicarbonate, carbonate and protons) on the physiologica...

Coccolithophores have influenced the global climate for over 200 million years. These marine phytoplankton can account for 20 per cent of total carbon fixation in some systems. They form blooms that can occupy hundreds of thousands of square kilometres and are distinguished by their elegantly sculpted calcium carbonate exoskeletons (coccoliths), re...

The advent of modern genomics has provided an unparalleled opportunity to consider the gene complement of an organism, and scrutinize metabolic pathways that are no longer active. This approach has led to an increasing number of reports of vitamin-associated pathway deterioration, with many indicating that independent gene-loss events of one or a f...

The motile green alga, Chlamydomonas, has long been used as a model system to understand flagella structure and function. In addition to the well characterised roles of cilia and flagella in motility, cell biologists are becoming increasingly aware of their importance as cellular sensors. Ca2+-dependent signalling mechanisms are associated with man...

A fundamental requirement of all eukaryotes is the ability to translocate protons across membranes. This is critical in bioenergetics, for compartmentalized metabolism, and to regulate intracellular pH (pH(i)) within a range that is compatible with cellular metabolism. Plants, animals, and algae utilize specialized transport machinery for membrane...

Anthropogenically released CO2 is dissolving in the ocean, causing a decrease in bulk-seawater pH (ocean acidification). Projections indicate that the pH will drop 0.3 units from its present value by 2100 (ref. 1). However, it is unclear how the growth of plankton is likely to respond. Using simulations we demonstrate how pH and carbonate chemistry...

Anthropogenically released CO2 is dissolving in the ocean, causing a decrease in bulk-seawater pH (ocean acidification). Projections indicate that the pH will drop 0.3 units from its present value by 2100 (ref. ). However, it is unclear how the growth of plankton is likely to respond. Using simulations we demonstrate how pH and carbonate chemistry...

Calcification in the coccolithophore Emiliania huxleyi is a tightly regulated process requiring the intracellular transport of Ca2+ and inorganic carbon. The presented work focuses on the mechanisms of calcification in E. huxleyi identifying key genes involved in Ca2+ and dissolved inorganic carbon (DIC) transport. An initial experiment involving t...

Membrane transporters play a central role in many cellular processes that rely on the movement of ions and organic molecules between the environment and the cell, and between cellular compartments. Transporters have been well characterized in plants and green algae, but little is known about transporters or their evolutionary histories in the red a...

Primer sequences for qRT-PCR. Forward (F) and reverse (R) primer pairs were designed to amplify regions of 200–300 bases for real-time PCR analysis. The alternative gene identity refers the name used by McGinn & Morel [23]. CA-7 has been previously identified by the protein ID 22619, although protein ID 34094 is used in the genome. (DOC)

Design of a single vessel for pH auxostat continuous culture. Cultures were bubbled continuously with air at either 760 µatm pCO2 or 380 µatm pCO2. Cultures were also stirred and pH was continuously monitored via a pH meter. An increase in pH triggered the pump, resulting in an influx of f/2 seawater media which was pre-equilibrated via aeration wi...