Otoferlin acts as a Ca2+ sensor for vesicle fusion and vesicle pool replenishment at auditory hair cell ribbon synapses

Hearing relies on rapid, temporally precise, and sustained neurotransmitter release at the ribbon synapses of sensory cells, the inner hair cells (IHCs). This process requires otoferlin, a six C2-domain, Ca2+-binding transmembrane protein of synaptic vesicles. To decipher the role of otoferlin in the synaptic vesicle cycle, we produced knock-in mice (Otof Ala515,Ala517/Ala515,Ala517) with lower Ca2+-binding affinity of the C2C domain. The IHC ribbon synapse structure, synaptic Ca2+ currents, and otoferlin distribution were unaffected in these mutant mice, but auditory brainstem response wave-I amplitude was reduced. Lower Ca2+ sensitivity and delay of the fast and sustained components of synaptic exocytosis were revealed by membrane capacitance measurement upon modulations of intracellular Ca2+ concentration, by varying Ca2+ influx through voltage-gated Ca2+-channels or Ca2+ uncaging. Otoferlin thus functions as a Ca2+ sensor, setting the rates of primed vesicle fusion with the presynaptic plasma membrane and synaptic vesicle pool replenishment in the IHC active zone

Circulating adrenomedullin estimates survival and reversibility of organ failure in sepsis: the prospective observational multinational Adrenomedullin and Outcome in Sepsis and Septic Shock-1 (AdrenOSS-1) study

Background: Adrenomedullin (ADM) regulates vascular tone and endothelial permeability during sepsis. Levels of circulating biologically active ADM (bio-ADM) show an inverse relationship with blood pressure and a direct relationship with vasopressor requirement. In the present prospective observational multinational Adrenomedullin and Outcome in Sepsis and Septic Shock 1 (, AdrenOSS-1) study, we assessed relationships between circulating bio-ADM during the initial intensive care unit (ICU) stay and short-term outcome in order to eventually design a biomarker-guided randomized controlled trial. Methods: AdrenOSS-1 was a prospective observational multinational study. The primary outcome was 28-day mortality. Secondary outcomes included organ failure as defined by Sequential Organ Failure Assessment (SOFA) score, organ support with focus on vasopressor/inotropic use, and need for renal replacement therapy. AdrenOSS-1 included 583 patients admitted to the ICU with sepsis or septic shock. Results: Circulating bio-ADM levels were measured upon admission and at day 2. Median bio-ADM concentration upon admission was 80.5 pg/ml [IQR 41.5-148.1 pg/ml]. Initial SOFA score was 7 [IQR 5-10], and 28-day mortality was 22%. We found marked associations between bio-ADM upon admission and 28-day mortality (unadjusted standardized HR 2.3 [CI 1.9-2.9]; adjusted HR 1.6 [CI 1.1-2.5]) and between bio-ADM levels and SOFA score (p < 0.0001). Need of vasopressor/inotrope, renal replacement therapy, and positive fluid balance were more prevalent in patients with a bio-ADM > 70 pg/ml upon admission than in those with bio-ADM ≤ 70 pg/ml. In patients with bio-ADM > 70 pg/ml upon admission, decrease in bio-ADM below 70 pg/ml at day 2 was associated with recovery of organ function at day 7 and better 28-day outcome (9.5% mortality). By contrast, persistently elevated bio-ADM at day 2 was associated with prolonged organ dysfunction and high 28-day mortality (38.1% mortality, HR 4.9, 95% CI 2.5-9.8). Conclusions: AdrenOSS-1 shows that early levels and rapid changes in bio-ADM estimate short-term outcome in sepsis and septic shock. These data are the backbone of the design of the biomarker-guided AdrenOSS-2 trial. Trial registration: ClinicalTrials.gov, NCT02393781. Registered on March 19, 2015

Inactivation of DltA Modulates Virulence Factor Expression in Streptococcus pyogenes

D-alanylated lipoteichoic acid is a virtually ubiquitous component of gram-positive cell walls. Mutations in the dltABCD operon of numerous species exhibit pleiotropic effects, including reduced virulence, which has been attributed to increased binding of cationic antimicrobial peptides to the more negatively charged cell surface. In this study, we have further investigated the effects that mutating dltA has on virulence factor expression in Streptococcus pyogenes.Isogenic Delta dltA mutants had previously been created in two distinct M1T1 isolates of S. pyogenes. Immunoblots, flow cytometry, and immunofluorescence were used to quantitate M protein levels in these strains, as well as to assess their ability to bind complement. Bacteria were tested for their ability to interact with human PMN and to grow in whole human blood. Message levels for emm, sic, and various regulatory elements were assessed by quantitative RT-PCR. Cell walls of Delta dltA mutants contained much less M protein than cell walls of parent strains and this correlated with reduced levels of emm transcripts, increased deposition of complement, increased association of bacteria with polymorphonuclear leukocytes, and reduced bacterial growth in whole human blood. Transcription of at least one other gene of the mga regulon, sic, which encodes a protein that inactivates antimicrobial peptides, was also dramatically reduced in Delta dltA mutants. Concomitantly, ccpA and rofA were unaffected, while rgg and arcA were up-regulated.This study has identified a novel mechanism for the reduced virulence of dltA mutants of Streptococcus pyogenes in which gene regulatory networks somehow sense and respond to the loss of DltA and lack of D-alanine esterification of lipoteichoic acid. The mechanism remains to be determined, but the data indicate that the status of D-alanine-lipoteichoic acid can significantly influence the expression of at least some streptococcal virulence factors and provide further impetus to targeting the dlt operon of gram-positive pathogens in the search for novel antimicrobial compounds

Shedding light on local kinase activation

Phosphorylation is the predominant language of cell signaling. And, as with any common language, an abundance of dialects has evolved to convey complex information. We discuss here how biosensors are being used to decode this language, affording an unprecedented glimpse into spatio-temporal patterns of protein phosphorylation events within the cell

Les teignes des lapins et leur traitement en France: une synthèse

[EN] In the rabbit, dermatophytosis (ringworm, favus) is mainly caused by two types of fungi, Mícrosporum canis and Trichophyton mentagrophytes, and infrequently by Microsporum gypseum. Fungus develops inside of the epidermis at a skin lesion after initial contamination by one spore or a mycelium fragment. For its development, the mycelium uses skin and hair keratin as substrate. Source of contamination is generally an infected animal (a rabbit but also a cat, a dog, a mouse, ... ) by direct contact or through its hair or skin particles. Raising conditions with excessive temperature, humidity or density favour development of the disease. Dermatophytosis may show a dry, and more or less circular depilated area, a suppurating area or a favus. Ringworm can be prevented by strictly controlled raising conditions, and by cleaning and disinfection of equipment. Vaccines have been described in sorne countries, but are not available in France. The field diagnosis must be followed by an experimental laboratory diagnosis by means of microscopic observation, use of a Wood's light fluorescence test, and mycelium culture. For the latter, a quick culture media kit is available. ldentification of the fungus is necessary for a complete diagnosis. For treatment, different efficient chemicals are available, but their use must be completed by decontamination of equipment (building, cages, feeders, ... ). The following chemicals are known for their antifungus activity : chlorhexidin, enilconazol, griseofulin, lkétoconazol, lnatamycin, iodinated povidone, thiabendazol, sulphur, caustic soda, copper sulphate. Local treatment of the skin is generally associated with oral treatment with griseofulvin (25 mg/kg LW or 750 mg/kg feed during 14 to 28 days) or with ketoconazol. Finally, it must be emphasised that rabbit dermatophytosis can be transmitted to man.[FR] Les teignes des lapins sont dues essentiellement a Mícrosporum canís et Trichophyton mentagrophytes. Mícrosporum gypseum peut aussi contaminer Oryctolagus cunículus. Le champignon pénetre dans l'épiderme a la faveur d'une lésion et se multiplie a partir d'une spore ou d'un fragment mycélien en utilisant pour substrat la kératine de la peau, des ongles ou des poils. La contamination se fait a partir d'un animal porteur. Les conditions d'élevage dépassant les normes (température, densité, hygrométrie) sont favorables au dÉveloppement des teignes. Les dermatophyties se manifestent sous forme de teignes séches tondante ou épilante, de teigne suppurée, de teigne favique. La prévention fait intervenir le nettoyage et le respect des normes d'élevage. Des vaccins contre T. mentagrophytes existent dans certains pays. Le diagnostic clinique doit etre suivi d'un diagnostic expérimental a l'aide d'observation microscopique, d'un examen avec une lampe de Wood et d'une culture (éventuellement faite sur des milieux dit de culture rapide). Ensuite, l'identification est indispensable a l'établissement du diagnostic. Le traitement fait appel a différentes molécules et doit etre complété par la décontamination du milieu d'élevage. La chlorhexidine, l'enilconazole, la griseofuline, le kétoconazole, la natamycine, la povidone iodée, le thiabendazole, le soufre, la soude, le sulfate de cuivre sont utilisés pour leur propriétés antifongiques. Le traitement local est souvent associé au traitement par voie orale a base de griséofulvine ou de kétoconazole. Enfin, les teignes sont de redoutables zoonosesBoucher, S.; Nouaille, L. (2001). Les teignes des lapins et leur traitement en France: une synthèse. World Rabbit Science. doi:10.4995/wrs.2001.709SWORD9

APPOSA (Improvement of Protein Production by Optimisation of the Stability of their Transcripts )

International audienc

Technical Note: Autovaccines against mycoplasmas in farm rabbits

[EN] Farm rabbits are affected by respiratory and reproductive disorders that compromise their health and the productivity of the farm. In two earlier papers we highlighted the role of mycoplasmas in these processes and the present article evaluates the usefulness of autovaccines to control mycoplasmosis. On a commercial rabbitry with 800 females, 428 kits were vaccinated, leaving 3,622 as controls. A lower mortality was observed among the vaccinated kits, with a significant (P<0.01) decrease in the presence of lung lesions.Boucher, S.; Nouaille, L.; Albizu, I.; Baselga, R. (2003). Technical Note: Autovaccines against mycoplasmas in farm rabbits. World Rabbit Science. 11(4):227-232. doi:10.4995/wrs.2003.510SWORD22723211