Éditeur(s) : HAL CCSD The Company of Biologists
Résumé : International audience
The ability to produce sound has been known for decades inBalistidae. Sounds of many species have been recorded and a varietyof sound-producing mechanisms have been proposed, includingteeth stridulation, collision of the buccal teeth and movements of thefins. The best-supported hypothesis involves movements of thepectoral fin against the lateral part of the swimbladder, called adrumming membrane. In this study, we describe for the first time thesounds made by the blackbar triggerfish Rhinecanthus aculeatus,which are like short drum rolls with an average duration of 85 ms,193 Hz dominant frequency and 136 dB SPL level at 3 cm distance.The sounds are a series of pulses that result from alternate sweepingmovements of the right and left pectoral fins, which push a system ofthree scutes that are forced against the swimbladder wall. Pulses fromeach fin occur in consecutive pairs. High-speed videos indicate thateach pulse consists of two cycles. The first part of each cyclecorresponds to the inward buckling of the scutes, whereas the secondpart of the cycle corresponds to an apparent passive recoil of thescutes and swimbladder wall. This novel sound productionmechanism is probably found in many members of Balistidaebecause these peculiar scutes occur in other species in the family.Comparison of sound characteristics from fishes of different sizesshows that dominant frequency decreases with size in juveniles butnot in adults.KEY WORDS: Acoustic, Communication, Swimbladder
ISSN: 00220949

hal-01472506
https://hal-univ-perp.archives-ouvertes.fr/hal-01472506
DOI : 10.1242/jeb.146514

Éditeur(s) : HAL CCSD Elsevier
Résumé : 00000 ăWOS:000386415300011
International audience
Highly biologically active marine sesquiterpene ilimaquinone was selected for chemical modifications. Its biotransformation was investigated using a combinatorial approach as an original way to screen different strains of microorganisms. Mucor circinelloides ATCC 8541 was able to structurally modify ilimaquinone into three different compounds. A stereospecific epoxidation was observed and compared to chemical epoxidation. A hydroxylation of the decalin ring was also observed as well as an unexpected substitution on the quinone ring by ethanolamine. Compounds were evaluated against several cell lines. (C) 2016 Elsevier Ltd. All rights reserved.
ISSN: 0040-4039

hal-01483185
https://hal.archives-ouvertes.fr/hal-01483185
DOI : 10.1016/j.tetlet.2016.09.075

Éditeur(s) : HAL CCSD Lippincott, Williams & Wilkins
Résumé : PURPOSE OF REVIEW: Malaria represents one of the most important selective factors affecting human populations. Several inherited diseases of red blood cells lead to resistance at the erythrocytic stage. Among patients who experience hereditary elliptocytosis related to mutations of erythrocyte membrane proteins, molecular studies have shown the prevalence of particular spectrin mutations in patients from black ethnic extraction, leading one to question the selection of new malaria-resistant genes. RECENT FINDINGS: Prospective epidemiological and molecular studies in West Africa have confirmed the prevalence (between 0.6 and 1.6%) of particular spectrin mutations related to hereditary elliptocytosis. These studies have also revealed the frequency of alpha-spectrin chain polymorphisms, associated in cis with elliptocytogenic spectrin mutations and defining particular spectrin allele haplotypes. Culture studies of Plasmodium falciparum in elliptocytes bearing such elliptocytogenic alleles of spectrin showed that these alleles are supplementary genetic factors of malaria resistance in vitro. SUMMARY: Certain instances of spectrin mutations or polymorphisms have not yet been shown to constitute new factors of innate resistance to malaria in vivo. Epidemiological surveys of hereditary elliptocytosis and parasite culture studies, however, have argued that the relationships between parasite and spectrin-based skeleton should be examined more closely and the molecular interactions between parasite ligands and particular spectrin chain domains should be characterized.
ISSN: 1065-6251

inserm-00128119
http://www.hal.inserm.fr/inserm-00128119
http://www.hal.inserm.fr/inserm-00128119/document
http://www.hal.inserm.fr/inserm-00128119/file/Dhermy_et_al_figures.pdf
DOI : 10.1097/MOH.0b013e3280d21afd