The cepacian-like exopolysaccharide of Paraburkholderia ultramafica STM10279T enhances growth and metal adaptation of Tetraria comosa on New Caledonian ultramafic soil

Paraburkholderia ultramafica STM10279T is a metal-tolerant rhizobacterium that promotes plant growth. It was isolated from the roots of Tetraria arundinaceae, a pioneer endemic tropical herb growing on ultramafic soils in New Caledonia. We have recently shown that the main mechanism of metal tolerance of P. ultramafica is related to the production of an acidic exopolysaccharide (EPS). To explore the potential role of this EPS in the plant’s environmental adaptation, we first elucidated its structure by employing a combination of chromatography and mass spectrometry techniques. These analyses revealed that the EPS is highly branched and composed of galactosyl (35.8%), glucosyl (33.2%), rhamnosyl (19.5%), mannosyl (7.2%), and glucuronosyl residues (4.4%), similar to the EPS of the Burkholderia cepacia complex known as cepacian. We subsequently conducted greenhouse experiments on Tetraria comosa plantlets inoculated with P. ultramafica or a solution of its EPS during transplanting onto ultramafic substrate. The data showed that the dry weight of T. comosa shoots was 2.5 times higher in the plants treated with the EPS compared to the unexposed plants. In addition, inductively coupled plasma–optical emission spectrometry (ICP-OES) analysis revealed that exposure to the EPS significantly increased Ca, Mg, K, and P uptake as well as K content in roots. In vitro experiments using the Pikovskaya method showed that the EPS was able to solubilize phosphorus. Consistent with the retention of metals in roots and a reduction in shoots, our data revealed a significant decrease in metal translocation factors (TFs) in the plants inoculated with the EPS. These results suggest a beneficial effect of the rhizobacterial EPS on plant growth and abiotic stress mitigation. In addition, the data suggest that the reduced levels of trace metals in plants exposed to P. ultramafica STM10279T are due to metal chelation by the EPS. Further investigations are needed to firmly demonstrate whether this EPS could be used as a biostimulant for plant growth and adaptation to ultramafic soils

Bioprospection and biodiversity of marine microorganisms issue from New Caledonia marine atypical areas : Research, Characterization, and Valuation of marine natural polymers

Le milieu marin constitue la plus grande partie de la biosphère et contient les formes les plus anciennes et les plus variées de la vie. Les espèces microbiennes, relativement négligées jusqu’à présent, pourraient bien être le principal gisement de nouvelles molécules des prochaines décennies grâce à leurs adaptations à un environnement marin atypique et/ou à des conditions extrêmes (zones hydrothermales, sédiments des fonds sous-marins, lagunes hyper-salines, continent arctique et antarctique, tapis microbiens…). La Nouvelle-Calédonie est dotée de milieux naturels littoraux, côtiers et marins au sein desquels existent des gradients thermiques, d’hypersalure/dessalure, de chocs UV, de pH, d’évaporation, d’inondation/exondation… qui déterminent des habitats atypiques dans lesquels les micro-organismes doivent développer des stratégies adaptatives et de défense potentiellement uniques. Un travail de bioprospection de ces milieux atypiques a ainsi permis la création d’une souchothèque riche à ce jour de 771 isolats bactériens néo-calédoniens. Sur la base de cette collection, des études ont été engagées pour la recherche et la caractérisation de biopolymères de type exopolysaccharides (EPS) et polyhydroxyalcanoates (PHA). Les EPS sont des complexes osidiques de grande taille dont la composition est variable selon l’organisme producteur. Les PHAs sont des macromolécules formées de liaisons ester présentant de fortes similitudes avec les plastiques issues de la pétrochimie mais sont totalement biodégradables et biocompatibles. Les débouchés pour la valorisation des biopolymères marins sont très variés et touche plusieurs secteurs comme la cosmétique (gélifiant épaississant, antirides, etc.) la santé (immunostimulation, anticoagulant, cicatrisant), l’agroalimentaire, la bioremédiation les emballages, l’enrobage… Les criblages réalisés sur l’ensemble de la collection pour les deux types de polymères ont permis de mettre en évidence qu’une part importante des souches de la collection étaient potentiellement capables de sécréter ces polymères. À l’heure actuelle, 10 types d’EPS et 5 types de PHAs ont été produits et caractérisés afin de cibler des domaines d’applications. L’étude des bactéries marines pour leur faculté à produire des polymères est donc un secteur en pleine expansion et les premiers résultats montrent que ce type de biotechnologies pourrait constituer une perspective de développement intéressante pour la Nouvelle-Calédonie.Previous works on marine bacteria led to the discovery of molecules of great biotechnological interest. Under unusual physical and chemical conditions some microorganisms have developed various survival strategies including exopolysaccharides (EPS) and Poly-3-hydroxyalkanoates (PHAs) production. Due to their many interesting biological, physical and chemical properties, those polymers have found applications in many industrial sectors. Due to interesting physical and chemical properties, EPS can find applications in many industrial sectors including the food industry, cosmetics, for oil and metal recovery from industrial waste and in the mining industry as well. During the last decades EPS have also been demonstrated as interesting bioactive molecules with many applications for human health. PHAs are biopolyesters accumulated as granules in bacteria in order to endure long starving periods. Those biodegradable biopolymers can be used as an alternative to petroleum derived polymers and can be produced from renewable carbon sources. PHAs exhibit a wide variety of properties and structures depending of the carbon source available and the microorganism used for the production. New Caledonia (NC) is frequently referred as a hotspot biodiversity. During a prospection campaign performed in different marine costal ecosystems of NC, a great number (770) of bacteria were isolated from different locations. Screening showed that 55% of the isolates were able to produce under lab conditions EPS and 53% to produce PHA. Partial chemical characterization was performed on purified samples using colorimetric methods, infrared spectrometry (FTIR), gas chromatography (GC) and nuclear magnetic resonance (NMR). Marine bacteria from New Caledonian ecosystems were shown to produce EPS with unusual chemical composition with potential applications in cosmetics. Preliminary experiments also showed high metal-binding capacity with applications in bioremediation. Different PHAs were also produced using different types of sugars and oil as renewable resources. Blue biotechnologies can have various applications in many industrial sectors (Health, food industry, environment, cosmetics etc…) and there is a great international demand for new molecules issue from marine areas. New Caledonian marine bacteria have proved their capacity for producing innovative biopolymers with a wide range of application that can be valuating in on short time period (environment, cosmetics) or at long time (pharmaceutics, surgeries). These applications are promising in order to develo

Η τραπεζική απιστία

Επίκαιρα ζητήματα τραπεζικής απιστίας μετά τη θέσπιση της κατ' έγκληση δίωξης των σχετικών κακουργηματικών αξιόποινων πράξεων με τον Ν. 4637/2019, το ζήτημα της λογιστικής αποτίμησης των απαιτήσεων από δάνεια και του κατά πόσο αυτή συνιστά βέβαιη βλάβη ή διακινδύνευση της περιουσίας, όταν το δάνειο χορηγείται σε αναξιόχρεο οφειλέτη.A topical study of the crime of breaching of fiduciary duties, commited against banking institutions, in the aftermath of recent legislation (Law no. 4637/2019) requiring prior report or accusation by the institution's representatives in order for a criminal trial to be initiated and felony charges to be brought, the question of the accounting valuation of loan claims and whether this constitutes damage or endangerment of the institution's property, when the loan is granted to an unworthy debtor

Anti-inflammatory activity of exopolysaccharides (EPS) from New Caledonian marine bacteria

International audienceImmune-mediated inflammatory diseases (IMIDs) represent a major global health issue with an incidence in Western society that approximates 5-7%. They are characterized by chronic inflammation, and corticoids or non-steroidal anti-inflammatory drugs (NSAIDs) are usually prescribed to regulate inflammatory response. Related severe side effects foster continue drug development that also focus on the regulation of signaling pathways of inflammatory cytokines with the recent use of cytokine-targeted monoclonal antibodies. However, these therapies could trigger the development of opportunistic diseases and patients might become refractory to these treatments. During the last decades, scientists draw their attention to the metal-control immunology, an interesting strategy in the drug development including chelators of metal ions as the deferoxamine.Natural products (NPs) are a source of innovative drugs and includes bioactive marine NPs (MNPs). Some MNPs isolated from marine microorganisms showed anti-inflammatory bioactivities including exopolysaccharides (EPS) that exert immunomodulatory activities. Considering the originality and the diversity of MNPs produced by New Caledonian marine microorganisms, we investigated the potential immunomodulatory activity of EPS from local marine bacteria. These EPS are available from the collection of the New Caledonian startup BIOTECAL. In vitro model of PMA-differentiated THP-1 macrophage was used to study the anti-inflammatory effect of 10 EPS. Cells were induced with LPS (1 µg/mL) with or without EPS at 250 ng/mL. The cytotoxicity was evaluated by quantifying the LDH released in the culture supernatant and confirmed no cytotoxicity for the EPS at the concentration tested. The production of cytokines was quantified by ELISA and the EPSs were shown to inhibit the release of inflammatory cytokines TNF-α and IL-6. A dose effect response for one of the most active EPS (BT17) was evaluated. The potential of chelating metal ions was evaluated by FTIR and SEM techniques for BT17. This work aimed at valorizing MNPs from New Caledonian marine biodiversity, answering on the one hand ongoing research in drug discovery. On the other hand, it responds to the local and national strategies for sustainable economic development based on biosourcing and blue technology

Guiding management in severe trauma: Reviewing factors predicting outcome in vastly injured patients

Trauma is one of the leading causes of death worldwide, with road traffic collisions, suicides, and homicides accounting for the majority of injury-related deaths. Since trauma mainly affects young age groups, it is recognized as a serious social and economic threat, as annually, almost 16,000 posttrauma individuals are expected to lose their lives and many more to end up disabled. The purpose of this research is to summarize current knowledge on factors predicting outcome – specifically mortality risk – in severely injured patients. Development of this review was mainly based on the systematic search of PubMed medical library, Cochrane database, and advanced trauma life support Guiding Manuals. The research was based on publications between 1994 and 2016. Although hypovolemic, obstructive, cardiogenic, and septic shock can all be seen in multi-trauma patients, hemorrhage-induced shock is by far the most common cause of shock. In this review, we summarize current knowledge on factors predicting outcome – more specifically mortality risk – in severely injured patients. The main mortality-predicting factors in trauma patients are those associated with basic human physiology and tissue perfusion status, coagulation adequacy, and resuscitation requirements. On the contrary, advanced age and the presence of comorbidities predispose patients to a poor outcome because of the loss of physiological reserves. Trauma resuscitation teams considering mortality prediction factors can not only guide resuscitation but also identify patients with high mortality risk who were previously considered less severely injured

New Caledonian ultramafic conditions structure the features of Curtobacterium citreum strains that play a role in plant adaptation

The present study is focused on the characterization of ten Curtobacterium citreum strains isolated from the rhizosphere of pioneer plants growing on ultramafic soils from New-Caledonia. Taxonomic status was investigated using a polyphasic approach. Three strains (BE, BB and AM) were selected in terms of multiple metal resistance and plant growth promoting traits. They were tested on Sorghum growing on ultramafic soil and compared with C. citreum DSM20528T used as reference strain. In order to better understand the bacterial mechanisms involved, biosorption, bioaccumulation and biofilm formation were investigated for the representative strain of the ultramafic cluster (BE) versus C. citreum DSM20528T. The polyphasic approach confirmed that all native isolates belong to the same cluster and are C. citreum. The inoculation of Sorghum by the strains BE and BB significantly reduced Ni content in shoots compared to inoculation with C. citreum DSM20528T and control values. This result was related with the higher Ni tolerance of the ultramafic strains compared to C. citreum DSM20528T. Ni biosorption and bioaccumulation showed that BE exhibited a lower Ni content explained by the ability of this strain to produce exopolysaccharides involved in Ni chelation. We suggested that ultramafic C. citreum strains are more adapted to this substrate than C. citreum DSM20528T and their features allow them to enhance plant metal tolerance.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author