Gene expression specificity of the mussel antifungal mytimycin (MytM).
We previously reported the nucleotide sequences and diversity of mytimycin (MytM) from the Mediterranean mussel, Mytilus galloprovincialis. Using real-time PCR (q-PCR), we observed that the MytM gene was mainly expressed in circulating hemocytes and to a less extent in the mantle. In vivo challenge with bacteria or with the yeast, Candida albicans, did not increase the expression as measured by q-PCR in hemocytes. By contrast, injection of the filamentous fungus, Fusarium oxysporum, induced a sudden and strong increase of expression at 9h p.i. (stimulation index of 25.7 ± 2.1). Optimum stimulating dose was 10(4) spores of F. oxysporum per mussel. In the same samples, AMP mytilin and myticin showed no stimulation. Consequently, we hypothesized the existence of 2 different signal transduction pathways, one activated by bacteria and yeast, the other triggered by filamentous fungi. A second challenge performed with F. oxysporum 24 h after the first challenge induced an increase of MytM gene expression (stimulation index of 3.5 ± 1.7). However, this second increase was significantly lower than the first, suggesting less efficient response rather than significant protection.
Ecologie des Systèmes Marins et Côtiers, Université Montpellier 2-CNRS, cc 093, place E. Bataillon, F-34095 Montpellier cedex 05, France.
Molruedee
M
Sonthi
Franck
F
Cantet
Mylène
M
Toubiana
Maria-Rosa
MR
Trapani
Maria-Giovanna
MG
Parisi
Matteo
M
Cammarata
Philippe
P
Roch
D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000235:genetics / Q000378:metabolism*; D005670:Fusarium / Q000502:physiology; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D006434:Hemocytes / Q000378:metabolism; D008837:Micrococcus / Q000502:physiology; D049878:Mytilus / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology*; D014733:Vibrio / Q000502:physiology; D047071:beta-Glucans / Q000494:pharmacology
D000276:Adjuvants, Immunologic; D023181:Antimicrobial Cationic Peptides; D047071:beta-Glucans