Karine Lemarchand

Karine Lemarchand
Université du Québec à Rimouski UQAR | uqar · Institut des Sciences de la Mer de Rimouski (ISMER)

Ph.D. Microbial ecology

About

53
Publications
9,565
Reads
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1,327
Citations
Citations since 2017
11 Research Items
422 Citations
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Introduction
I'm a marine microbial ecologist who loves working with prokaryotes. My current projects deal with the effect of different pollutants (nanomaterials and HAP) on the behaviour of natural microbial communities in an optic of bioremediation and general microbial adaptation to stressfull conditions.
Additional affiliations
October 2003 - present
Université du Québec à Rimouski UQAR
Position
  • Effects of anthropogenic pressures on marine bacterial communities
May 2002 - August 2003
National Research Council Canada
Position
  • PostDoc Position
January 2002 - September 2003
Biotechnology research institut, NRC, Montréal, Qc, Canada
Position
  • Detection of pathogens in water by DNA Microarrray
Education
January 2002 - August 2003
NRC-BRI
Field of study
  • Environmental microbiology
October 1998 - December 2001
Claude Bernard University Lyon 1
Field of study
  • Microbial Ecology

Publications

Publications (53)
Article
This study describes aggregation kinetics of silver nanoparticles (AgNPs) and particle size distribution (PSD) of silver aggregates at concentrations ranging from 10 mgAg.L⁻¹ to 10 µgAg.L⁻¹. Aggregation kinetics were conducted at different NaCl concentrations for 2 h and at three environmentally NaCl concentrations (9, 86 and 428 mM) for 12 h to de...
Article
Vibrio splendidus is a marine bacterium often considered as a threat in aquaculture hatcheries where it is responsible for mass mortality events, notably of bivalves’ larvae. This bacterium is highly adapted to dynamic salty ecosystems where it has become an opportunistic and resistant species. To characterize their membranes as a first and necessa...
Article
Full-text available
Little is known about the base of the food web that could support the high productivity and marine biodiversity found in San Jorge Gulf, Patagonia, Argentina. Here we examine the key components of the microbial food web, including the standing stock and physiological state of the phytoplankton in the context of key oceanographic variables in the gu...
Poster
Full-text available
In bivalve hatcheries, opportunistic pathogens have been associated with important mass mortality events of larvae and important economic lost for producers. New alternatives to the use of antibiotics, such as probiotics, have been proposed to limit the occurrence of such events in bivalve hatcheries and to stabilize bivalve production. Probiotics...
Chapter
Full-text available
Environmental Toxicity of Nanomaterials focuses on causes and prevention of environmental toxicity induced by various nanomaterials. In sixteen chapters it describes the basic principles, trends, challenges, and future directions of nanoecotoxicity. The future acceptance of nanomaterials in various industries depends on the impacts of nanomaterial...
Article
There is an important need for the development of new "environmentally-friendly" antifouling molecules to replace toxic chemicals actually used to fight against marine biofouling. Marine biomass is a promising source of non-toxic antifouling products such as natural antimicrobial peptides produced by marine organisms. The aim of this study was to d...
Poster
Full-text available
Presentation of my research proposal for my MSc thesis on the response of the blue mussel larvae to a prophylactic probiotic (marennine) used to prevent mass mortality due to the presence of an opportunistic bacterial pathogen in conchyliculture.
Article
This paper explores the possibility of using the supernatant of Haslea ostrearia culture containing maren-nine, a natural microalgal pigment, as an antimicrobial in bivalve hatcheries. The blue mussel Mytilus edulis and the scallop Placopecten magellanicus were used as model animals, and the pathogenic marine bacteria Vibrio splendidus was used to...
Chapter
The implementation of molecular techniques, and more recently the rise of metagenomic studies applied in marine systems, has revolutionized our understanding of marine ecology, especially in microbial research. Preparation of high-quality, representative, nucleic acids from cultures and raw marine samples is the basis of all molecular approaches. P...
Article
Full-text available
This paper explores the possibility of using the supernatant of Haslea ostrearia culture containing maren-nine, a natural microalgal pigment, as an antimicrobial in bivalve hatcheries. The blue mussel Mytilus edulis and the scallop Placopecten magellanicus were used as model animals, and the pathogenic marine bacteria Vibrio splendidus was used to...
Book
The implementation of molecular techniques, and more recently the rise of metagenomic studies applied in marine systems, has revolutionized our understanding of marine ecology, especially in microbial research. Preparation of high-quality, representative, nucleic acids from cultures and raw marine samples is the basis of all molecular approaches. P...
Article
As the study of interactions between pathogenic microorganisms and their environment is part of microbial ecology, this chapter reviews the different types of human pathogens found in the environment, the different types of fecal indicators used in water quality monitoring, the biotic and abiotic factors affecting the survival and the infectivity o...
Article
Full-text available
The aim of this study was to evaluate the stability of AgNPs suspensions in different exposure solutions characteristic of natural waters or culture medium used in microbial ecotoxicology studies. The behavior of AgNPs in solution depends on the physicochemical characteristics of the receptor media. In nanopure water, the size of AgNPs was stable o...
Article
Full-text available
After the required incubation time of 18 h in the dark at room temperature (20°C), the microplates were drained using the inversion method and the cells were resuspended and fixed with 0.5% formaldehyde. The samples were then read by a flow cytometer (BD Accuri™ C6, Becton Dickinson, San Jose, CA, USA). The hemocyte populations were defined based o...
Article
Full-text available
In Canada, about 30000 tons of marine by-products from snow crab (Chionoecetes opilio) fisheries are generated annualy and currently disposed in landfills. These co-products contain biopolymers, such as peptide extracts, and some are known to interact with metallic surfaces and have an antibacterial activity. These properties suggest that snow crab...
Data
Full-text available
ABSTRACT Marine planktonic communities can be affected by the increase in temperature associated with global change, as well as by the increase in ultraviolet B radiation (UVBR, 280-320 nm) through stratospheric ozone layer thinning. The goal of this work was to study the individual and combined effects of increased temperature and UVBR on the pla...
Data
Full-text available
Marine planktonic communities can be affected by increased temperatures associated with global climate change, as well as by increased ultraviolet B radiation (UVBR, 280-320 nm) through stratospheric ozone layer thinning. We studied individual and combined effects of increased temperature and UVBR on the plankton community of the Beagle Channel, so...
Article
The potential toxic effects of carboxylated (COOH) single-walled carbon nanotubes (SWNTs) were investigated on the cell growth and viability of two reference (Silicibacter pomeroyi, Oceanospirillum beijerinckii) and two environmental (Vibrio splendidus, Vibrio gigantis) Gram-negative marine bacterial strains. Bacterial cells were exposed to six con...
Conference Paper
Full-text available
Tons of marine by-products are available from snow-crab (Chionocete opilio) fisheries and contain valuable biopolymers; among others snow crab peptide extracts (SCPE). Some of these biopolymers are known to interact with metallic surfaces and have an antibacterial activity. Both properties making them good candidates to inhibit corrosion, as well a...
Article
Rotifers (Brachionus plicatilis), commonly used at first feeding in commercial fish hatcheries, carry a large bacteria load. Because they are relatively poor in essential fatty acids, it is common practice to enrich them with fatty acids, including arachidonic acid (AA). This study aims to determine whether prey enrichment with AA may act as a preb...
Data
##Assembly-Data-START## Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##
Article
Full-text available
Mussels are widespread in coastal environments and experience various physical, chemical, and bacteriological conditions. Owing to the increase of coastal urbanization, mussels are now commonly exposed not only to indigenous bacteria, but also to enteric bacteria originating from pulsed and chronic sewage discharges into coastal environments. Due t...
Article
Full-text available
The use of silver nanoparticles (AgNPs) in consumer products is increasing drastically and their potential environmental impacts on aquatic organisms from bacterial communities to vertebrates are not well understood. This study reports on changes in marine bacterial richness using denaturing gradient gel electrophoresis (DGGE), and overall communit...
Article
Full-text available
In this paper, biochemical and physiological analyses were used to characterize changes associated with mortality event occurred during veliger development of American oyster, Crassostrea virginica. Biochemical analy-ses included the evaluation of lipid classes, fatty acid composition and total protein content. Larval physiology was evaluated by st...
Article
The proliferation of bacteria in intensive aquaculture systems may be responsible for poor growth and mass mortality of marine fish larvae. Essential fatty acids provided in the diet could protect larvae by modulation of the immune response via arachidonic acid (AA) and eicosapentaenoic acid (EPA). Winter flounder Pseudopleuronectes americanus larv...
Article
In this paper, biochemical and physiological analyses were used to characterize changes associated with mortality event occurred during veliger development of American oyster, Crassostrea virginica. Biochemical analyses included the evaluation of lipid classes, fatty acid composition and total protein content. Larval physiology was evaluated by stu...
Article
Full-text available
Although winter conditions play a major role in determining the productivity of the western Antarctic Peninsula (WAP) waters for the following spring and summer, a few studies have dealt with the seasonal variability of microorganisms in the WAP in winter. Moreover, because of regional warming, sea-ice retreat is happening earlier in spring, at the...
Article
Full-text available
The temporal changes in dissolved inorganic (DIC) and organic carbon concentrations (DOC) were monitored from late autumn to spring 2006 in the Scholaert Channel, West Antarctic Peninsula. Surface DIC spanned a small range (2163.3 to 2194.5 mmol kg -1), increasing from late autumn to winter and then decreasing in spring. An excess of DOC (7.0–63.6...
Article
Full-text available
Microphytobenthic diatom communities were investigated in the high and low sections of two salt marshes of the Lower St. Lawrence Estuary (eastern Canada): one featuring a sandy low marsh zone (Pointe-aux-Épinettes; PE) and one with a muddy low marsh area (Pointe-au-Père; PP). Based on diatom composition and diversity, bacterial abundance, chloroph...
Article
Full-text available
Microbial uptake of carbon monoxide (CO) in the Gulf of St. Lawrence and the estuary of the St. Lawrence River, Canada, typically followed first-order kinetics at ambient CO concentrations, [CO], but saturation kinetics occasionally occurred in spring. The first-order uptake rate constant, Kco, decreased from the upper estuary (8.48 d–1) to the low...
Article
Full-text available
Ecological concerns about antifouling paints containing non-green tin and copper compounds have highlighted the need for environmentally friendly alternatives. We report here a field test conducted in estuarine waters over two months designed to evaluate the efficiency of a number of active natural and man-made chemical ingredients added into a sil...
Article
Full-text available
A small-oligonucleotide microarray prototype was designed with probes specific for the universal 16S rRNA and cpn60 genes of several pathogens that are usually encountered in wastewaters. In addition to these two targets, wecE-specific oligonucleotide probes were included in the microarray to enhance its discriminating power within the Enterobacter...
Article
Numerous waterborne pathogens are difficult to detect and enumerate with accuracy due to methodological limitations and high costs of direct culturing. The purity of DNA extracted from wastewater samples is an important issue in the sensitivity and the usefulness of molecular methods such as polymerase chain reaction (PCR) and hybridizations on DNA...
Article
Full-text available
Public concern over polluted water is a major environmental issue worldwide. Microbial contamination of water arguably represents the most significant risk to human health on a global scale. An important challenge in modern water microbial quality monitoring is the rapid, specific, and sensitive detection of microbial indicators and waterborne path...
Article
Cryptosporidium and Salmonella are pathogenic microorganisms that can cause severe gastrointestinal illness in humans. Because these organisms are potentially transmitted through natural waters, this study was carried out to estimate the concentrations of both pathogens in a French coastal watershed and to determine the relationships with fecal ind...
Article
Abstract In aquatic environments, the survival of pathogenic microorganisms, such as Salmonella spp., may represent a risk to public health. The mutation frequency was hypothesized to influence the persistence of Salmonella serotypes in environmental waters. The mean mutation frequency to rifampin resistance of the 11 major serotypes of Salmonella...
Article
In aquatic environments, the survival of pathogenic microorganisms, such as Salmonella spp., may represent a risk to public health. The mutation frequency was hypothesized to influence the persistence of Salmonella serotypes in environmental waters. The mean mutation frequency to rifampin resistance of the 11 major serotypes of Salmonella enterica...
Article
Full-text available
Rapid microbiology and the detection of rare events are important challenges in various fields of aquatic microbiology. Epifluorescence microscopy, flow cytometry and solid-phase cytometry are techniques used for direct methods in microbiology but the range of application of these different instruments is not clearly defined. In this study, we exam...
Article
The efficiency of ChemChrome B (CB) and ChemChrome V6 (CV6) dyes to stain viable bacterial cells in water was compared. Both dyes are fluorogenic esters converted to free fluorescein by esterase activity. The dyes were applied to a wide variety of bacterial species, including those poorly stained by CB, and to natural waters. Some species tested ga...
Article
Full-text available
Salmonella species are pathogenic bacteria often detected in sewage, freshwater, marine coastal water, and groundwater.Salmonella spp. can survive for long periods in natural waters, and the persistence of specific and epidemic strains is of great concern in public health. However, the diversity of species found in the natural environment remains u...
Article
The CSE dye (Chemunex, Maisons-Alfort, France) was combined with an activity marker to improve bacterial activity assessment in natural waters. Its effectiveness to counterstain dead cells with permeabilised membranes was investigated on live and dead cells of a variety of strains from collections or isolated from the natural environment. Cells wer...
Article
The CSE dye (Chemunex, Maisons-Alfort, France) was combined with an activity marker to improve bacterial activity assessment in natural waters. Its effectiveness to counterstain dead cells with permeabilised membranes was investigated on live and dead cells of a variety of strains from collections or isolated from the natural environment. Cells wer...

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