“Pomacytosis”—Semi-extracellular phagocytosis of cyanobacteria by the smallest marine algae

Kamennaya, Nina A.; Kennaway, Gabrielle; Fuchs, Bernhard M.; Zubkov, Mikhail V.

doi:10.1371/journal.pbio.2003502

Cited by 26 publications

(24 citation statements)

References 40 publications

(50 reference statements)

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“…Furthermore, OTUs far outnumber the number of morphologically described or nutritionally described species that have been sequenced; at present, there is no way of differentiating the mixotrophs among the many OTUs typically recorded in molecular datasets. Meanwhile, experimental studies continue to provide increasing evidence that more and more species previously thought to be “strictly” photoautotrophic phytoplankton are, in fact, CMs (e.g., Berge et al, ; Hoppenrath & Leander, ; Jang et al, ; Kamennaya, Kennaway, Fuchs, & Zubkov, ; Kang et al, ; Lim et al, ; Nézan & Chomérat, ; Ok et al, ; Yoo et al, ).…”

Section: Discussionmentioning

confidence: 99%

Sampling bias misrepresents the biogeographical significance of constitutive mixotrophs across global oceans

Leles

Mitra

Flynn

et al. 2019

Global Ecol Biogeogr

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Aim Most protist plankton are mixotrophic, with potential to engage in photoautotrophy and phagotrophy; however, the ecology of these organisms has been misdiagnosed for over a century. A large proportion of these organisms are constitutive mixotrophs (CMs), with an innate ability to photosynthesize. Here, for the first time, an analysis is presented of the biogeography of CMs across the oceans. Location Global marine ecosystems. Time period 1970–2018. Major taxa studied Marine planktonic protists. Methods Records for CM species, primarily from the Ocean Biogeographic Information System (OBIS), were grouped by taxonomy and size to evaluate sampling efforts across Longhurst's oceanic provinces. Biases were evaluated through nonparametric tests and multivariate analysis. Biogeographies of CMs from OBIS data were compared with data from studies that specifically targeted these organisms. Results Constitutive mixotrophs of different taxonomic groups, across all size ranges, are ubiquitous. However, strong database biases were detected with respect to organism size, taxonomic groups and region. A strong bias was seen towards dinophytes. Species < 20 µm, especially non‐dinophytes, were least represented, with their recorded distribution limited to coastal regions and to temperate and polar seas. Studies specifically targeting these organisms revealed their distribution to be much wider. Such biases are likely to have occurred owing to a failure to capture and correctly identify these organisms in routine sampling protocols. Main conclusions Constitutive mixotrophs are dominant members of organisms traditionally termed “phytoplankton”. However, lack of routine protocols for measuring phagotrophy in “phytoplankton” protists has led to widespread misrepresentation of the fundamental nature of marine planktonic primary producers; most express both “animal‐like” and “plant‐like” nutrition. Our results have implications for studies of the global biogeography of plankton, of food web dynamics (including models) and of biogeochemical cycling in the oceans.

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Section: Discussionmentioning

confidence: 99%

Sampling bias misrepresents the biogeographical significance of constitutive mixotrophs across global oceans

Leles

Mitra

Flynn

et al. 2019

Global Ecol Biogeogr

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“…WH8109 cells were flow cytometrically differentiated from other bacteria by their specific autofluorescence. Using a custom-built MoFlo XDP instrument 68 , WH8109 cells were flow-sorted in batches of 10-200 cells directly into sterile tubes with ASW medium. Tubes were placed into an illuminated growth chamber and incubated until growth became evident by colour.…”

Section: Methodsmentioning

confidence: 99%

“…strain WH8102 (0.1-1 × 10 6 cells) (Supplementary Table 3). Cells were flow-sorted onto 0.2 μm pore size polycarbonate filters (P free) using the custom-built MoFlo XDP instrument 68 . The filters with dried sorted cells were mounted on a custom-made sample holder and the cell-containing filter areas (~1000 × 2000 µm) were probed with a beam spot of 30 × 30 µm 2 in a helium atmosphere ( Supplementary Fig.…”

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Accumulation of ambient phosphate into the periplasm of marine bacteria is proton motive force dependent

et al. 2020

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Bacteria acquire phosphate (P i) by maintaining a periplasmic concentration below environmental levels. We recently described an extracellular P i buffer which appears to counteract the gradient required for P i diffusion. Here, we demonstrate that various treatments to outer membrane (OM) constituents do not affect the buffered P i because bacteria accumulate P i in the periplasm, from which it can be removed hypo-osmotically. The periplasmic P i can be gradually imported into the cytoplasm by ATP-powered transport, however, the proton motive force (PMF) is not required to keep P i in the periplasm. In contrast, the accumulation of P i into the periplasm across the OM is PMF-dependent and can be enhanced by light energy. Because the conventional mechanism of P i-specific transport cannot explain P i accumulation in the periplasm we propose that periplasmic P i anions pair with chemiosmotic cations of the PMF and millions of accumulated P i pairs could influence the periplasmic osmolarity of marine bacteria.

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“…To ensure that sheath-water bacterioplankton, rather than suspended benthic bacteria, were analysed we compared bacterial abundance in samples collected from more than 5 m above the bottom to those in water samples carefully collected by a remotely operated vehicle (ROV) ~1 m above the bottom. Furthermore we assessed the composition of bacterioplankton for potential "contamination" with re-suspended benthic bacteria using high-throughput sequencing of flow sorted cells 22 . In the absence of established methods for reliably determining growth of deep-ocean bacterioplankton, we combined two different approaches.…”

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confidence: 99%

Bacterioplankton reveal years-long retention of Atlantic deep-ocean water by the Tropic Seamount

Giljan

Kamennaya

Otto³

et al. 2020

Sci Rep

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Seamounts, often rising hundreds of metres above surrounding seafloor, obstruct the flow of deepocean water. While the retention of deep-water by seamounts is predicted from ocean circulation models, its empirical validation has been hampered by large scale and slow rate of the interaction. to overcome these limitations we use the growth of planktonic bacteria to assess the retention time of deep-ocean water by a seamount. the selected tropic Seamount in the north-eastern Atlantic is representative for the majority of isolated seamounts, which do not affect the surface ocean waters. We prove deep-water is retained by the seamount by measuring 2.4× higher bacterial concentrations in the seamount-associated or 'sheath'-water than in deep-ocean water unaffected by seamounts. Genomic analyses of flow-sorted, dominant sheath-water bacteria confirm their planktonic origin, whilst proteomic analyses of the sheath-water bacteria, isotopically labelled in situ, indicate their slow growth. According to our radiotracer experiments, it takes the sheath-water bacterioplankton 1.5 years to double their concentration. therefore, the seamount should retain the deep-ocean water for 1.8 years for the deep-ocean bacterioplankton to grow to the 2.4× higher concentration in the sheathwater. We propose that turbulent mixing of the seamount sheath-water stimulates bacterioplankton growth by increasing cell encounter rate with ambient dissolved organic molecules.The 1,000-year-long global thermohaline circulation 1 connects the bulk deep water of the modern World Ocean, irrespective of barriers erected by continents, islands and thousands of seamounts 2-4 . While continents and islands shape the circulation, seamounts affect this deep-water flow by creating enclosed circulation cells 5 , thereby reducing exchange between the so-called 'sheath-water' retained by seamounts and the surrounding deep water.This does not, however, mean that the sheath-water is stagnant. The interaction of seamounts with deep water currents and waves (internal and tidal) causes complex sheath-water dynamics 6 , specified by the unique geometry of individual seamounts 5 . The complexity arises from interactions of parallel, rapid, turbulent mixing at centimetre-scales on seamount slopes 7,8 and much slower flowing circulations (including Taylor columns) at the seamount-scale 9 . The complex sheath-water dynamics shapes seamount habitats for resident benthos and plankton 5,10,11 , causes erosion, controls sedimentation and affects ferromanganese crust formation on seamount slopes 12 .A number of seamounts peak close to the ocean surface and mix nutrient-rich deep water with the nutrient-poor surface water enhancing local phytoplankton growth 13 and causing a surface seamount effect 5,13,14 ; retention of the produced organic matter in the seamount proximity raises productivity and enriches diversity of the entire seamount-associated ecosystem 9,10,[15][16][17][18][19] . The majority of seamounts do not cause the surface seamount effect because their summits are ...

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“Pomacytosis”—Semi-extracellular phagocytosis of cyanobacteria by the smallest marine algae

Cited by 26 publications

References 40 publications

Sampling bias misrepresents the biogeographical significance of constitutive mixotrophs across global oceans

Sampling bias misrepresents the biogeographical significance of constitutive mixotrophs across global oceans

Accumulation of ambient phosphate into the periplasm of marine bacteria is proton motive force dependent

Bacterioplankton reveal years-long retention of Atlantic deep-ocean water by the Tropic Seamount

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