scholarly journals Virus-host coexistence in phytoplankton through the genomic lens

2019 ◽  
Author(s):  
Yau Sheree ◽  
Marc Krasovec ◽  
Stephane Rombauts ◽  
Mathieu Groussin ◽  
L. Felipe Benites ◽  
...  
Keyword(s):  
Single Cell ◽  
Orthologous Genes ◽  
Hedging Strategy ◽  
Continuous Growth ◽  
Phase Switching ◽  
Host Interactions ◽  
Boom And Bust ◽  
Nw Mediterranean ◽  
Nw Mediterranean Sea ◽  
Virus Interactions

AbstractPhytoplankton-virus interactions are major determinants of geochemical cycles in the oceans. Viruses are responsible for the redirection of carbon and nutrients away from larger organisms back towards microorganisms via the lysis of microalgae in a process coined the ‘viral shunt’. Virus-host interactions are generally expected to follow ‘boom and bust’ dynamics, whereby a numerically dominant strain is lysed and replaced by a virus resistant strain. Here, we isolated a microalga and its infective nucleo-cytoplasmic large DNA virus (NCLDV) concomitantly from the environment in the surface NW Mediterranean Sea, Ostreococcus mediterraneus, and show continuous growth in culture of both the microalga and the virus. Evolution experiments through single cell bottlenecks demonstrate that, in the absence of the virus, susceptible cells evolve from one ancestral resistant single cell, and vice–versa; that is that resistant cells evolve from one ancestral susceptible cell. This provides evidence that the observed sustained viral production is the consequence of a minority of virus-susceptible cells. The emergence of these cells is explained by low-level phase switching between virus-resistant and virus-susceptible phenotypes, akin to a bet hedging strategy. Whole genome sequencing and analysis of the ~14 Mb microalga and the ~200 kb virus points towards ancient speciation of the microalga within the Ostreococcus species complex and frequent gene exchanges between prasinoviruses infecting Ostreococcus species. Re-sequencing of one susceptible strain demonstrated that the phase switch involved a large 60 Kb deletion of one chromosome. This chromosome is an outlier chromosome compared to the streamlined, gene dense, GC-rich standard chromosomes, as it contains many repeats and few orthologous genes. While this chromosome has been described in three different genera, its size increments have been previously associated to antiviral immunity and resistance in another species from the same genus. Mathematical modelling of this mechanism predicts microalga–virus population dynamics consistent with the observation of continuous growth of both virus and microalga. Altogether, our results suggest a previously overlooked strategy in phytoplankton–virus interactions.

scholarly journals Variability of ultraplankton composition and distribution in an oligotrophic coastal ecosystem of the NW Mediterranean Sea derived from a two-year survey at the single cell level

PLoS ONE ◽  
2017 ◽  
Vol 12 (12) ◽  
pp. e0190121 ◽  
Author(s):  
Maria Luiza Pedrotti ◽  
Laure Mousseau ◽  
Sophie Marro ◽  
Ornella Passafiume ◽  
Marjorie Gossaert ◽  
...  
Keyword(s):  
Single Cell ◽  
Mediterranean Sea ◽  
Coastal Ecosystem ◽  
Single Cell Level ◽  
Cell Level ◽  
Nw Mediterranean ◽  
Nw Mediterranean Sea

scholarly journals Viral coinfection is shaped by host ecology and virus-virus interactions across diverse microbial taxa and environments

2016 ◽  
Author(s):  
Samuel L. Díaz Muñoz
Keyword(s):  
Single Cell ◽  
Strong Predictor ◽  
Viral Evolution ◽  
Data Sets ◽  
Host Interactions ◽  
Two Factors ◽  
Comprehensive Picture ◽  
Host Ecology ◽  
Viral Coinfection ◽  
Virus Interactions

AbstractInfection of more than one virus in a host, coinfection, is common across taxa and environments. Viral coinfection can enable genetic exchange, alter the dynamics of infections, and change the course of viral evolution. Yet, a systematic test of the factors explaining variation in viral coinfection across different taxa and environments awaits completion. Here I employ three microbial data sets of virus-host interactions covering cross-infectivity, culture coinfection, and single-cell coinfection (total: 6,564 microbial hosts, 13,103 viruses) to provide a broad, comprehensive picture of the ecological and biological factors shaping viral coinfection. I found evidence that ecology and virus-virus interactions are recurrent factors shaping coinfection patterns. Host ecology was a consistent and strong predictor of coinfection across all three datasets: cross-infectivity, culture coinfection, and single-cell coinfection. Host phylogeny or taxonomy was a less consistent predictor, being weak or absent in the cross-infectivity and single-cell coinfection models, yet it was the strongest predictor in the culture coinfection model. Virus-virus interactions strongly affected coinfection. In the largest test of superinfection exclusion to date, prophage sequences reduced culture coinfection by other prophages, with a weaker effect on extrachromosomal virus coinfection. At the single-cell level, prophage sequences eliminated coinfection. Virus-virus interactions alsoincreasedculture coinfection with ssDNA-dsDNA coinfections >2x more likely than ssDNA-only coinfections. The presence of CRISPR spacers was associated with a ~50% reduction in single-cell coinfection in a marine bacteria, despite the absence of exact spacer matches in any active infection. Collectively, these results suggest the environment bacteria inhabit and the interactions among surrounding viruses are two factors consistently shaping viral coinfection patterns. These findings highlight the role of virus-virus interactions in coinfection with implications for phage therapy, microbiome dynamics, and viral infection treatments.

scholarly journals Host preferences of coexisting Perkinsea parasitoids during coastal dinoflagellate blooms

2021 ◽  
Author(s):  
Albert Reñé ◽  
Natàlia Timoneda ◽  
Nagore Sampedro ◽  
Elisabet Alacid ◽  
Rachele Gallisai ◽  
...  
Keyword(s):  
Species Interactions ◽  
Wide Distribution ◽  
Host Preferences ◽  
Host Interactions ◽  
High Infection ◽  
Nw Mediterranean ◽  
Nw Mediterranean Sea ◽  
The Relationship ◽  
Preferred Hosts ◽  
Specific Parasite

ABSTRACTParasites in aquatic systems are highly diverse and ubiquitous. In marine environments, parasite-host interactions contribute substantially to shaping microbial communities, but their nature and complexity remain poorly understood. In this study, we examined the relationship between Perkinsea parasitoids and bloom-forming dinoflagellate species. Our aim was to determine whether parasite-host species interactions are specific and whether the diversity and distribution of parasitoids are shaped by their dinoflagellate hosts. Several locations along the Catalan coast (NW Mediterranean Sea) were sampled during the blooms of five dinoflagellate species and the diversity of Perkinsea was determined by combining cultivation-based methods with metabarcoding of the V4 region of 18S rDNA. Most known species of Parviluciferaceae, and others not yet described, were detected, some of them coexisting in the same coastal location, and with a wide distribution. The specific parasite-host interactions determined for each of the studied blooms demonstrated the host preferences exhibited by parasitoids in nature. The dominance of a species within the parasitoid community is driven by the presence and abundances of its preferred host(s).The absence of parasitoid species, often associated with a low abundance of their preferred hosts, suggested that high infection rates are reached only under conditions that favour parasitoid propagation, especially dinoflagellate blooms.

Main drivers of spatial change in the biomass of commercial species between summer and winter in the NW Mediterranean Sea

2020 ◽  
pp. 105227
Author(s):  
Elena Lloret-Lloret ◽  
Maria Grazia Pennino ◽  
Daniel Vilas ◽  
José María Bellido ◽  
Joan Navarro ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Spatial Change ◽  
Commercial Species ◽  
Nw Mediterranean ◽  
Nw Mediterranean Sea

scholarly journals Impact of mechanized clam dredging on the discarded megabenthic fauna on the Catalan coast (NW Mediterranean)

2021 ◽  
pp. 1-9
Author(s):  
Marc Baeta ◽  
Claudia Rubio ◽  
Françoise Breton
Keyword(s):  
Small Scale ◽  
Fishing Activity ◽  
Lethal Damage ◽  
Catalan Coast ◽  
Nw Mediterranean ◽  
Chamelea Gallina ◽  
Level Scale ◽  
Nw Mediterranean Sea ◽  
The Impact ◽  
Partial Damage

Abstract There is an important small-scale fishery using mechanized dredges and targeting clams (mainly wedge clam Donax trunculus and striped venus clam Chamelea gallina) along the Catalan coast (NW Mediterranean Sea). This study evaluated for the first time the discards and impact of mechanized clam dredging on the Catalan coast. To this end, three surveys were performed on board standard clam vessels (September and November 2016 and January 2017). Surveys were conducted in the three main clam fishing areas (Rosas Bay, South Barcelona and Ebro Delta). The composition of discards and the impact caused to discarded species was assessed using a three-level scale (undamaged; minor or partial damage; and lethal damage). Our study revealed that a large proportion of the catch (between 67–82% weight) is discarded. Even though about 63% of the discarded species were undamaged, 11% showed minor or partial damage and 26% lethal damage. Infaunal and epifaunal species with soft-body or fragile shells were the most impacted by the fishing activity (e.g. the sea urchin Echinocardium mediterraneum (~89%) and the bivalve Ensis minor (~74%)). Our results showed different levels of impact by target species and fishing area.

scholarly journals Environmental occurrence of phthalate and organophosphate esters in sediments across the Gulf of Lion (NW Mediterranean Sea)

2020 ◽  
pp. 143412
Author(s):  
Nigar Alkan ◽  
Ali Alkan ◽  
Javier Castro-Jiménez ◽  
Florian Royer ◽  
Laure Papillon ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Organophosphate Esters ◽  
Gulf Of Lion ◽  
Nw Mediterranean ◽  
Nw Mediterranean Sea

Composition and provenance of terrigenous organic matter transported along submarine canyons in the Gulf of Lion (NW Mediterranean Sea)

2013 ◽  
Vol 118 ◽  
pp. 81-94 ◽  
Author(s):  
Catalina Pasqual ◽  
Miguel A. Goñi ◽  
Tommaso Tesi ◽  
Anna Sanchez-Vidal ◽  
Antoni Calafat ◽  
...  
Keyword(s):  
Organic Matter ◽  
Mediterranean Sea ◽  
Submarine Canyons ◽  
Terrigenous Organic Matter ◽  
Gulf Of Lion ◽  
Nw Mediterranean ◽  
Nw Mediterranean Sea

7000 years of paleostorm activity in the NW Mediterranean Sea in response to Holocene climate events

2012 ◽  
Vol 77 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Pierre Sabatier ◽  
Laurent Dezileau ◽  
Christophe Colin ◽  
Louis Briqueu ◽  
Frédéric Bouchette ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
North Atlantic ◽  
Clay Mineralogy ◽  
Mediterranean Coast ◽  
Ice Age ◽  
Storm Activity ◽  
The North ◽  
Nw Mediterranean ◽  
The North Atlantic ◽  
Nw Mediterranean Sea

A high-resolution record of paleostorm events along the French Mediterranean coast over the past 7000 years was established from a lagoonal sediment core in the Gulf of Lions. Integrating grain size, faunal analysis, clay mineralogy and geochemistry data with a chronology derived from radiocarbon dating, we recorded seven periods of increased storm activity at 6300–6100, 5650–5400, 4400–4050, 3650–3200, 2800–2600, 1950–1400 and 400–50 cal yr BP (in the Little Ice Age). In contrast, our results show that the Medieval Climate Anomaly (1150–650 cal yr BP) was characterised by low storm activity.The evidence for high storm activity in the NW Mediterranean Sea is in agreement with the changes in coastal hydrodynamics observed over the Eastern North Atlantic and seems to correspond to Holocene cooling in the North Atlantic. Periods of low SSTs there may have led to a stronger meridional temperature gradient and a southward migration of the westerlies. We hypothesise that the increase in storm activity during Holocene cold events over the North Atlantic and Mediterranean regions was probably due to an increase in the thermal gradient that led to an enhanced lower tropospheric baroclinicity over a large Central Atlantic-European domain.

Transformation of PBDE mixtures during sediment transport and resuspension in marine environments (Gulf of Lion, NW Mediterranean Sea)

2012 ◽  
Vol 168 ◽  
pp. 87-95 ◽  
Author(s):  
Joan A. Salvadó ◽  
Joan O. Grimalt ◽  
Jordi F. López ◽  
Xavier Durrieu de Madron ◽  
Serge Heussner ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Mediterranean Sea ◽  
Marine Environments ◽  
Gulf Of Lion ◽  
Nw Mediterranean ◽  
Nw Mediterranean Sea
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