freshwater

PhD project

Phytoplankton viruses in peri-alpine lakes

A New Freshwater Cyanosiphovirus Harboring Integrase

This work reports the first genome and genomic analysis of a freshwater cyanosiphovirus. With the largest BS and the longest period needed after infection before cells lyse ever found in a cyanosiphovirus infecting a PE-rich picocyanobacterium, atypical and original genomic features as well as a widespread distribution in aquatic systems, S-LBS1 and related viruses are likely to be key components in controlling and structuring Synechococcus populations. This report therefore fills a gap in the database where cyanosiphovirus genomes from freshwaters are still absent to date. Certainly, this will lend a support to those who want to investigate cyanosiphoviruses in freshwater environments, using either PCR- or metagenomic-based methods.

Methods and Technologies to Assess Viral Interactions in the Aquatic World

In this chapter, we summarize and discuss methods used to study viral interactions in aquatic environments. These methods to assess interactions between viruses, hosts and the environment (including other viruses) are operationally separated into …

Virus Interactions in the Aquatic World

During the past 30 years, a vast amount of articles has been published on the importance - in terms of abundance, diversity and functional roles - of viruses inhabiting the aquatic world (either marine or freshwater), which include several excellent …

Structure and diversity of ssDNA Microviridae viruses in two peri-alpine lakes (Annecy and Bourget, France)

Microviridae is a subset of single-stranded DNA (ssDNA) viruses infecting bacteria. This group of phages has been previously observed to be very abundant (representing 90% of the total known viral metagenomic sequences) in Lake Bourget. However, this …

Contrasting diversity of phycodnavirus signature genes in two large and deep western European lakes

Little is known about Phycodnavirus (or double‐stranded DNA algal virus) diversity in aquatic ecosystems, and virtually, no information has been provided for European lakes. We therefore conducted a 1‐year survey of the surface waters of France's two …

Differing assemblage composition and dynamics in T4‐like myophages of two neighbouring sub‐alpine lakes

Bacteriophages play an important role in plankton population dynamics and biogeochemical cycling, but their community dynamics and diversity are still poorly known, especially in fresh waters. We conducted a 1‐year investigation of the T4‐like …

Seasonal variations in PCR-DGGE fingerprinted viruses infecting phytoplankton in large and deep peri-alpine lakes

Double-stranded DNA viruses infecting eukaryotic algae (e.g., phycodnaviruses) and cyanobacteria (e.g., cyanophages) are now recognized as widespread and ubiquitous in aquatic environments. However, both the diversity and functional roles of these …

Dynamics of auto- and heterotrophic picoplankton and associated viruses in Lake Geneva

Microbial dynamics have rarely been investigated in Lake Geneva, known as the largest lake in western Europe. From a 5-month survey, we report dynamic patterns of free-living virus, bacteria and small phytoplankton abundances in response to a variety …

Variations in abundance, genome size, morphology, and functional role of the virioplankton in Lakes Annecy and Bourget over a 1-year period.

We sampled the surface waters (2–50 m) of two deep peri-alpine lakes over a 1-year period in order to examine (1) the abundance, vertical distribution, genome size, and morphology structures of the virioplankton; (2) the virus-mediated bacterial …