Michel Le Hénaff

• Ph.D
• École Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine

/////Preamble: This poster is a slightly improved version of the poster presented at the "Phages in Bordeaux" conference in Bordeaux (France) on 24 and 25 September 2018. This poster has been presented in French but we also offer an English version. ///// Intensive farming practices expose the French trout farming sector to various health challenge...

/////Preamble: This poster has been presented in French but we also offer an English version.///// Flavobacterium psychrophilum is a bacterium that infects farmed salmonids causing the bacterial cold water disease (BCWD), affecting adult fish on the American continent, or rainbow trout fry syndrome (RTFS) causing significant economic losses in Eur...

Intensive farming practices expose the French trout farming sector to various health challenges, among which the most problematic so far is the emergence of Flavobacterium psychrophilum, the causative agent of Rainbow Trout Fry Syndrome (RTFS). In parallel with the prophylactic measures undertaken to limit the spread of the pathogen, the intensive...

Melanins are the most widespread pigments in animals but their adaptive significance remains elusive. Recent studies suggest that intraspecific variation in melanin-based coloration reflects individual genetic-based alternative strategies to cope with environment variability, which could be crucial for their responses to climate changes. However, e...

Evaluation of the reduction of microbial biofilms by new cleaning formulations that combine pine derivatives and enzymes. Purpose. In the food industry and in healthcare, microbial biofilms can be a source of contamination. In particular, they may be involved in 65% of healthcare associated infections. This study evaluated the effectiveness of two...

The two parallel experiments described in this article were led in an order to identify the effect of age on carcass, muscles and meat properties of sucking lambs exclusively fed with mother’s milk. A jury made up of experts assessed visually and from a gustatory point of view the legs of two groups of six lambs slaughtered at respectively 40 and 8...

The effective conditions of glutaraldehyde, chloramine-T, bronopol, Incimaxx Aquatic ® and hydrogen peroxide as some biocides commonly used by the aquaculture industry were investigated against F. psychrophilum in sanitization of rainbow trout eyed eggs. Bacteriostatic tests as well as bactericidal tests using ethidium monoazide bromide PCR assays...

The aim of the present study was to assess the prevalence of the flavobacteria within farmed trout and to quantify their bacterial burden. A total of 61 fish were sampled from seven farms, and were distributed in two groups: (1) visibly diseased fish suffering from the rainbow trout fry syndrome or the bacterial cold water disease caused by the bac...

A qPCR assay was developed for rapid and sensitive detection of Flavobacterium psychrophilum, the aetiological agent of bacterial cold-water disease and rainbow trout fry syndrome in salmonid fish worldwide. A set of F. psychrophilum-specific primers based on 16S rRNA gene sequences was designed and validated for specific detection and quantificati...

Flavobacterium psychrophilum is an important infectious Gram-negative bacterium causing cold-water disease (CWD) and rainbow trout fry syndrome. Outer-membrane proteins (OMPs) are key molecules with regard to the interface between the cell and its environment. Therefore, we sought to define the outer-membrane (OM) subproteome of F. psychrophilum in...

The purpose of this study was to characterize OmpA, a major glycoprotein isolated from the membrane fraction of Flavobacterium psychrophilum, and to evaluate its potential as antigenic unit in a possible vaccine. The expression product of ompA is a 465-amino-acid protein precursor that contains a 21-amino acid signal peptide and has overall homolog...

We report here the complete genome sequence of the virulent strain JIP02/86 (ATCC 49511) of Flavobacterium psychrophilum, a widely distributed pathogen of wild and cultured salmonid fish. The genome consists of a 2,861,988-base pair (bp) circular chromosome with 2,432 predicted protein-coding genes. Among these predicted proteins, stress response m...

Investigations of the surface characteristics of Flavobacterium psychrophilum, an important pathogen of fish, assisted us in identifying a surface protein termed P18. In the current study, we developed a simple and efficient procedure for the purification of this protein by a two-step method. First, P18 was selectively released from flavobacteria b...

This study was focused on the identification of associated outer membrane proteins which may play a role in the specific interactions between Flavobacterium psychrophilum (the aetiological agent of cold-water disease and rainbow trout fry syndrome in salmonid fish worldwide) and the fish tissues. The surface protein interactions with the outer memb...

The cell envelope of the fish pathogen Flavobacterium psychrophilum contains more than 50 polypeptides resolved by sodium dodecyl sulphate-polyacrylaminde gel electrophoresis analysis including a major component named P60. Here, we have developed a simple and efficient procedure for the purification of P60 and therefore permitting its biochemical c...

The plasma membrane of Spiroplasma apis contains a 28-kDa major protein (P28), like other spiroplasmas which also possess a main 26- to 28-kDa membrane polypeptide, called spiralin. In the work described here, we have developed a simple and efficient method for the purification of P28 of this mollicute, a wall-less eubacteria. Proteins were first s...

The lipid modification of membrane proteins was investigated in Acholeplasma laidlawii by metabolic labeling and by chemical analysis. A S-glycerylcysteine residue was identified from membrane proteins and we reported the strong preference for saturated acyl chains into the lipid modification. Differential release of fatty acids revealed a ratio [(...

Two membrane proteins from the avian pathogen Mycoplasma gallisepticum have been previously purified using a simple, efficient and non-denaturing method: a lipoprotein P67 (pMGA) and P52. In the current study, the lipid part of P67 was chemically analysed. The molecular structure of the lipoprotein-lipid component was determined to be S-glyceryl cy...

The plasma membrane of Spiroplasma melliferum contains a major membrane-associated lipoprotein called spiralin. In this study, the processing pathway of spiralin was investigated by chemical analysis of the purified protein and by using [35S]cysteine, [35S]methionine, [14C]myristic acid (14C-14:0), [14C]palmitic acid (14C-16:0), and globomycin. SDS...

Revealed by in vivo labeling with (14)C-palmitic acid, about 15 acylated proteins were identified in the plasma membrane of Mycoplasma agalactiae (type strain PG2), including the major component p40. Triton X-114 phase partitioning and Western blotting demonstrated the amphiphilic properties of the acyl proteins and showed that they were also antig...

Mycoplasmas are bacteria which can cause respiratory, arthritic, and urogenital diseases. During the early phase of infection, mycoplasmas usually induce an inflammatory response and a humoral response preferentially directed against their membrane-bound, surface-exposed lipoproteins. In this report, we describe the effects on immune cells of spira...

The cyclic lipopeptide globomycin, a specific inhibitor of signal-peptidase II (Lsp A), proved toxic for the mollicute Spiroplasma melliferum with a minimal inhibitory concentration (MIC) in the range 6.25-12.5 microM, about one order of magnitude higher (that is, less efficient) than bee-venom mellitin. SDS-PAGE analysis of cell proteins followed...

The plasma membrane of Mycoplasma mycoides subsp. mycoides SC (strain KH3J) contains over 160 polypeptides with apparent molecular masses ranging from 14 to 125 kDa and isoelectric point values (pIs) from 5 to 9. In vivo labeling with [14C]-fatty acids revealed about 35 acylated polypeptides including the two major components p42 and p65 and displa...

The acylation of Mycoplasma gallisepticum membrane proteins was studied by electrophoresis after in vivo labelling with different 14C-fatty acids and by chemical analysis. The immunological properties of these proteins were investigated by Western blotting and crossed immunoelectrophoresis. Among the ca. 200 membrane polypeptides resolved by two-di...

The stable maintenance and expression of foreign genes in mollicutes (mycoplasmas) have been difficult to achieve due to the lack of suitable vectors. In this paper we show for the first time that a replicating vector can been used to express foreign genes other than antibiotic resistance genes in Acholeplasma laidlawii. Plasmids derived from the l...

The major protein (protein H) of the outer membrane of Pasteurella multocida was purified by size-exclusion chromatography after selective extraction with detergents. The protein forms homotrimers which are stable in the presence of SDS at room temperature. Upon treatment at 100 degrees C, the protein is fully dissociated by the detergent into mono...

The amino acid sequence of spiralin deduced from the nucleotide sequence of its gene was fictitiously shortened by 1 to 50 residues from each terminus and the compositions of both series of theoretical polypeptides were calculated. The two series of compositions thus obtained were compared to that of the purified protein, with the use of the Marcha...

Four spiralins were compared by rocket immunoelectrophoresis, quantitative immunoblotting techniques, and the spiroplasma deformation test with the use of antispiralin (polyclonal) monospecific antibodies. This investigation revealed that the spiralins of Spiroplasma citri and S. melliferum are antigenically related and that probably no more than t...

Antibodies were elicited in rabbits against periplasmic proteins obtained by cold osmotic shock from the Gram-negative eubacterium Rhizobium meliloti. When analyzed by crossed immunoelectrophoresis (CIE), the periplasmic proteins gave rise to 20 distinct immunoprecipitates corresponding to the same number of bands in polyacrylamide gel electrophore...