Arnica montana : évaluation des ressources génétiques françaises en vue du développement de la culture en plaine et en montagne

Ce volume regroupe les textes issus du programme Casdar "Innovation et Partenariat" et "Recherche finalisée et innovation" de 2013. Le colloque de restitution s’est déroulé le 6 février 2019 sous l’égide du GIS Relance AgronomiqueArnica montana is a major medicinal specie, which is now mainly produced from wild harvesting,especially in mainland France. As the wild resource is decreasing, and in order to maintain or even Gourlin L. et al. 68 Innovations Agronomiques 71 (2019), 67-80 develop the French production, cultivation is a good option, that is still very limited, because of its difficulty. Finding the right plant material could help to enhance cultivation programs. This project aimed at growing 24 wild populations, which were collected in mainland France, and to compare them with 2 commercial varieties, ‘Arbo’ and ‘Arnimed’. This was set on 4 experimentation spots, chosen for their potential match for Arnica cultivation. The experiment lasted 3 years, and morphological andagronomical subjects were studied on the populations. Sesquiterpene lactones and flavonoidsanalyzed, and a new methodology of evaluation was developed. The results showed extreme variabilityof phenotypic and chemical expression of the different populations. An important death rate has beennoticed on wild populations, but the causes are still unknown. On the set of variables chosen,commercial varieties ‘Arbo’ and ‘Arnimed’ were particularly competitive, and two wild populations standout with promising results. One seems appropriate for starting selection works on a variety that would besuitable for loaw altitude, and the other one could be a local (French) alternative to the cultivation ofselected varieties (‘Arbo’ and ‘Arnimed’ are from Swiss and German selection work).L’arnica des montagnes est une espèce médicinale importante dont la production est principalementissue de la cueillette à l’état sauvage, notamment sur le territoire métropolitain. La ressource étant enrégression, le maintien, voire le développement de la production française passe donc par la mise enculture, actuellement anecdotique car difficile. Certains freins pourraient être levés par la mise enévidence de matériel végétal adapté à la production. L’objectif de ce projet était de mettre en culture 24populations d’origines sauvages (prospectées en France métropolitaine) et de les comparer à deuxvariétés commerciales témoins ‘Arbo’ et ‘Arnimed’, sur 4 sites d’expérimentation aux contextespédoclimatiques variés mais a priori adaptés à la culture de l’espèce. Durant les 3 années d’essai, unsuivi morphologique et agronomique des populations a été réalisé. Des analyses des sesquiterpèneslactones et flavonoïdes ont été effectuées, et une nouvelle méthodologie de dosage de ces composés aété développée. Les résultats mettent en exergue la forte variabilité de l’expression phénotypique etchimique des différentes souches testées. Une forte mortalité globale a pu être constatée surl’ensemble des populations sauvages étudiées sans que les causes aient pu en être identifiées. Surl’ensemble des variables suivies, les variétés commerciales ‘Arbo’ et ‘Arnimed’ sont particulièrementperformantes, et deux populations sauvages se démarquent par leurs résultats intéressants : l’uneparait pertinente pour démarrer des travaux de sélection d’une variété adaptée à la basse altitude,tandis que l’autre, originaire du Massif central, pourrait se proposer comme une alternative d’originelocale (française) à la culture de variétés commerciales sélectionnées (suisse et allemande)

The porin and the permeating antibiotic: A selective diffusion barrier in gram-negative bacteria

Gram-negative bacteria are responsible for a large proportion of antibiotic resistant bacterial diseases. These bacteria have a complex cell envelope that comprises an outer membrane and an inner membrane that delimit the periplasm. The outer membrane contains various protein channels, called porins, which are involved in the influx of various compounds, including several classes of antibiotics. Bacterial adaptation to reduce influx through porins is an increasing problem worldwide that contributes, together with efflux systems, to the emergence and dissemination of antibiotic resistance. An exciting challenge is to decipher the genetic and molecular basis of membrane impermeability as a bacterial resistance mechanism. This Review outlines the bacterial response towards antibiotic stress on altered membrane permeability and discusses recent advances in molecular approaches that are improving our knowledge of the physico-chemical parameters that govern the translocation of antibiotics through porin channel

Anti-infectives in Drug Delivery-Overcoming the Gram-Negative Bacterial Cell Envelope.

Infectious diseases are becoming a major menace to the state of health worldwide, with difficulties in effective treatment especially of nosocomial infections caused by Gram-negative bacteria being increasingly reported. Inadequate permeation of anti-infectives into or across the Gram-negative bacterial cell envelope, due to its intrinsic barrier function as well as barrier enhancement mediated by resistance mechanisms, can be identified as one of the major reasons for insufficient therapeutic effects. Several in vitro, in silico, and in cellulo models are currently employed to increase the knowledge of anti-infective transport processes into or across the bacterial cell envelope; however, all such models exhibit drawbacks or have limitations with respect to the information they are able to provide. Thus, new approaches which allow for more comprehensive characterization of anti-infective permeation processes (and as such, would be usable as screening methods in early drug discovery and development) are desperately needed. Furthermore, delivery methods or technologies capable of enhancing anti-infective permeation into or across the bacterial cell envelope are required. In this respect, particle-based carrier systems have already been shown to provide the opportunity to overcome compound-related difficulties and allow for targeted delivery. In addition, formulations combining efflux pump inhibitors or antimicrobial peptides with anti-infectives show promise in the restoration of antibiotic activity in resistant bacterial strains. Despite considerable progress in this field however, the design of carriers to specifically enhance transport across the bacterial envelope or to target difficult-to-treat (e.g., intracellular) infections remains an urgently needed area of improvement. What follows is a summary and evaluation of the state of the art of both bacterial permeation models and advanced anti-infective formulation strategies, together with an outlook for future directions in these fields

The satisfactory growth and development at 2 years of age of the INTERGROWTH-21st Fetal Growth Standards cohort support its appropriateness for constructing international standards.

BACKGROUND: The World Health Organization recommends that human growth should be monitored with the use of international standards. However, in obstetric practice, we continue to monitor fetal growth using numerous local charts or equations that are based on different populations for each body structure. Consistent with World Health Organization recommendations, the INTERGROWTH-21st Project has produced the first set of international standards to date pregnancies; to monitor fetal growth, estimated fetal weight, Doppler measures, and brain structures; to measure uterine growth, maternal nutrition, newborn infant size, and body composition; and to assess the postnatal growth of preterm babies. All these standards are based on the same healthy pregnancy cohort. Recognizing the importance of demonstrating that, postnatally, this cohort still adhered to the World Health Organization prescriptive approach, we followed their growth and development to the key milestone of 2 years of age. OBJECTIVE: The purpose of this study was to determine whether the babies in the INTERGROWTH-21st Project maintained optimal growth and development in childhood. STUDY DESIGN: In the Infant Follow-up Study of the INTERGROWTH-21st Project, we evaluated postnatal growth, nutrition, morbidity, and motor development up to 2 years of age in the children who contributed data to the construction of the international fetal growth, newborn infant size and body composition at birth, and preterm postnatal growth standards. Clinical care, feeding practices, anthropometric measures, and assessment of morbidity were standardized across study sites and documented at 1 and 2 years of age. Weight, length, and head circumference age- and sex-specific z-scores and percentiles and motor development milestones were estimated with the use of the World Health Organization Child Growth Standards and World Health Organization milestone distributions, respectively. For the preterm infants, corrected age was used. Variance components analysis was used to estimate the percentage variability among individuals within a study site compared with that among study sites. RESULTS: There were 3711 eligible singleton live births; 3042 children (82%) were evaluated at 2 years of age. There were no substantive differences between the included group and the lost-to-follow up group. Infant mortality rate was 3 per 1000; neonatal mortality rate was 1.6 per 1000. At the 2-year visit, the children included in the INTERGROWTH-21st Fetal Growth Standards were at the 49th percentile for length, 50th percentile for head circumference, and 58th percentile for weight of the World Health Organization Child Growth Standards. Similar results were seen for the preterm subgroup that was included in the INTERGROWTH-21st Preterm Postnatal Growth Standards. The cohort overlapped between the 3rd and 97th percentiles of the World Health Organization motor development milestones. We estimated that the variance among study sites explains only 5.5% of the total variability in the length of the children between birth and 2 years of age, although the variance among individuals within a study site explains 42.9% (ie, 8 times the amount explained by the variation among sites). An increase of 8.9 cm in adult height over mean parental height is estimated to occur in the cohort from low-middle income countries, provided that children continue to have adequate health, environmental, and nutritional conditions. CONCLUSION: The cohort enrolled in the INTERGROWTH-21st standards remained healthy with adequate growth and motor development up to 2 years of age, which supports its appropriateness for the construction of international fetal and preterm postnatal growth standards