Effects of Sodium Azide on the Abundance of Prokaryotes and Viruses in Marine Samples

Flow cytometry is set to become the standard method for enumerating prokaryotes and viruses in marine samples. However, the samples need to be flash-frozen in liquid nitrogen directly after aldehyde fixation. Because liquid nitrogen may not always be available, we tested the potential of sodium azide as a preservative for prokaryotes and viruses in marine samples as a possible alternative. For that we conducted incubation experiments with untreated and sodium azide treated marine water samples at 4°C and room temperature. The data indicate that sodium azide cannot be used to maintain marine samples used for the enumeration of prokaryotes and viruses

Somatostatin and opioid receptors do not regulate proliferation or apoptosis of the human multiple myeloma U266 cells

International audienc

Phenotypic and genotypic comparison of antimicrobial-resistant variants of Escherichia coli and Salmonella Typhimurium isolated from evolution assays with antibiotics or commercial products based on essential oils

On account of the widespread development and propagation of antimicrobial-resistant (AMR) bacteria, essential oils (EOs) have emerged as potential alternatives to antibiotics. However, as already observed for antibiotics, recent studies have raised concerns regarding the potential emergence of resistant variants (RVs) to EOs. In this study, we assessed the emergence of RVs in Escherichia coli and Salmonella enterica Typhimurium after evolution assays under extended exposure to subinhibitory doses of two commercial EOs (AEN and COLIFIT) as well as to two antibiotics (amoxicillin and colistin). Phenotypic characterization of RVs from evolution assays with commercial EOs yielded no relevant increases in the minimum inhibitory concentration (MIC) of E. coli and did not even modify MIC values in S. Typhimurium. Conversely, RVs of E. coli and S. Typhimurium isolated from evolution assays with antibiotics showed increased resistance. Genotypic analysis demonstrated that resistance to commercial EOs was associated with enhanced protection against oxidative stress and redirection of cell energy toward efflux activity, while resistance to antibiotics was primarily linked to modifications in the cell binding sites of antibiotics. These findings suggest that AEN and COLIFIT could serve as safe alternatives to antibiotics in combating the emergence and dissemination of antimicrobial resistance within the agrifood system

Pembrolizumab Enhances the Anti-Leukemia Activity of Antigen Specific Cytotoxic T Lymphocytes

https://openworks.mdanderson.org/sumexp23/1074/thumbnail.jp

Dopamine D3 receptor dysfunction prevents anti-nociceptive effects of morphine in the spinal cord

Abstract Dopamine (DA) modulates spinal reflexes, including nociceptive reflexes, in part via the D3 receptor subtype. We have previously shown that mice lacking the functional D3 receptor (D3KO) exhibit decreased paw withdrawal latencies from painful thermal stimuli. Altering the DA system in the CNS, including D1 and D3 receptor systems, reduces the ability of opioids to provide analgesia. Here, we tested if the increased pain sensitivity in D3KO might result from a modified μ-opioid receptor (MOR) function at the spinal cord level. As D1 and D3 receptor subtypes have competing cellular effects and can form heterodimers, we tested if the changes in MOR function may be mediated in D3KO through the functionally intact D1 receptor system. We assessed thermal paw withdrawal latencies in D3KO and wild type (WT) mice before and after systemic treatment with morphine, determined MOR and phosphorylated MOR (p-MOR) protein expression levels in lumbar spinal cords, and tested the functional effects of DA and MOR receptor agonists in the isolated spinal cord. In vivo, a single morphine administration (2 mg/kg) increased withdrawal latencies in WT but not D3KO, and these differential effects were mimicked in vitro, where morphine modulated spinal reflex amplitudes (SRAs) in WT but not D3KO. Total MOR protein expression levels were similar between WT and D3KO, but the ratio of pMOR/total MOR was higher in D3KO. Blocking D3 receptors in the isolated WT cord precluded morphine's inhibitory effects observed under control conditions. Lastly, we observed an increase in D1 receptor protein expression in the lumbar spinal cord of D3KO. Our data suggest that the D3 receptor modulates the MOR system in the spinal cord, and that a dysfunction of the D3 receptor can induce a morphine-resistant state. We propose that the D3KO mouse may serve as a model to study the onset of morphine resistance at the spinal cord level, the primary processing site of the nociceptive pathway

Le cas néo-zélandais

The Case of New Zealand, by Ariel Kerros There are many who have noticed a significant difference between the anti-nuclear movement growing in New Zealand from those of Western Europe and the United States. It seems that the gut reaction of fear engendered by forecasts of nuclear holocaust has been exploited for électoral purposes. Similarly, the militants campaigning against atomic testing are not perhaps without ulterior motive considering that the role of « leader » in this region has not yet been filled. Unless New Zealand makes up its mind to leave the Western bloc and remain indiffèrent to destabilisation of the Western defence System, it would appear to be mounting a dangerous horse at a time when the Soviet Union is manifesting new interest in the South Pacific. For, to use a médical analogy, « kiwi fever » might well prove to be a very contagious disease.Force est de constater que l'allergie au nucléaire n'a pas germé de la même façon en Nouvelle-Zélande que dans l'Europe de Ouest et aux Etats-Unis. Il semble que la réaction viscérale de peur que fait naître l'évocation de apocalypse nucléaire ait été exploitée à des fins électorales. De même, la bannière du militantisme contre les essais atomiques n'est peut-être pas brandie sans arrière-pensées dans une région où le rôle de « leader » reste à prendre. A moins d'avoir décidé de quitter le bloc occidental et de n'avoir cure de déstabiliser le système de défense de ce dernier, il paraît bien dangereux d'enfourcher un tel cheval de bataille au moment même où les observateurs signalent un intérêt nouveau des Soviétiques pour le Pacifique Sud. Car, pour reprendre une comparaison médicale, la « kiwi fever » risque fort d'être un mal contagieux.Kerros Ariel. Le cas néo-zélandais. In: Politique étrangère, n°1 - 1987 - 52ᵉannée. pp. 61-70

Modulation de la prolifération cellulaire et de l apoptose des cellules de myélome multiple (MM) par les récepteurs couplés aux protéines G, les arrestines et le peptide OFQ3/Noc III, dérivé de la pronociceptine ([thèse soutenue sur un ensemble de travaux])

L objectif de ce travail porte sur la modulation des voies de signalisation anormalement activées dans les cellules d hémopathies malignes par les récepteurs opioïdes, les récepteurs à la somatostatine et les arrestines. Après avoir caractérisé ces récepteurs dans les lignées de MM, nous avons démontré que l U50 488 (agoniste des récepteurs opioïdes kappa) induit un léger blocage de prolifération et une potentialisation de l apoptose induite par Fas, via un mécanisme indépendant des récepteurs opioïdes dans les cellules LP-1. Dans un second temps, nous avons pu montrer que la somatostatine et l octréotide, agonistes des récepteurs à la somatostatine, seuls ou combinés à la morphine étaient incapables de moduler la prolifération et l apoptose les cellules U266 de MM. Nous avons démontré qu un peptide dérivé de la pronociceptine, l OFQ3/Noc III, est capable d induire l apoptose dans les cellules U266 par un mécanisme caspase-indépendant impliquant la libération d AIF. Enfin, dans un dernier temps, nous avons étudié le rôle des arrestines dans la prolifération et l apoptose des cellules U266. La surexpression de la b arrestine 2-GFP induit une diminution de prolifération et une augmentation de l apoptose caspase-dépendante. Ces effets sont associés à une augmentation d expression protéique de p27 et de l activité de liaison du facteur de transcription NF- B. De plus, la présence d une plus grande quantité de chromosomes dans cette lignée suggère l apparition d une catastrophe mitotique. Ces effets sont également retrouvés mais à un degré moindre avec le mutant constitutivement actif de l arrestine (R169E). En conclusion, ces résultats ouvrent des perspectives vers de nouvelles voies thérapeutiques dans le traitement du myélome multiple.The aim of this work was to discover new pathways to regulate proliferation and to induce apoptosis in malignant haematological cells. We examined the role of opioid and somatostatin receptors, known as G-protein coupled receptors (GPCR), arrestins and a pronociceptin-derived peptide, OFQ3/Noc III. After characterization of those GPCR in multiple myeloma (MM) cells, we demonstrated that U50 488 (a kappa selective opioid agonist) induced a weak blockage of proliferation and a potentiation of Fas-induced apoptosis through a non-opioid receptor mechanism. We proved that somatostatin and octreotide, somatostatin receptor agonists, alone or combined with morphine were not able to modulate apoptosis and proliferation in MM cells. We showed that the pronociceptine-derived peptide OFQ3/Noc III induced caspase-independent apoptosis by activating AIF in U266 MM cells. Finally, by overexpressing b arrestin2-GFP in the U266 cells, we demonstrated its role in proliferation and apoptosis. These effects were coupled with an increase of p27 protein expression and an increase of NF- B binding activity. Apoptosis associated with an increase in chromosome number suggested the occurrence of mitotic catastrophe. Those effects were also observed but to a lesser extent when the dominant negative mutant of arrestin, R169E, was overexpressed. In conclusion, our work shows that new therapeutic strategies could be considered for the treatment of multiple myeloma.CAEN-BU Sciences et STAPS (141182103) / SudocSudocFranceF

Flow cytometric assessment of the antimicrobial properties of an essential oil mixture against Escherichia coli

International audienceEssential oils are increasingly being used in human health and animal farming as alternatives to antibiotics. The aim of this study was to better understand the mode of antimicrobial action of a natural essential oil mix (EO mix) by comparison with the colistin, as an antibiotic. The growth inhibitory concentration (GIC) of the EO mix and colistin was determined by turbidimetry. Escherichia coli exposed to EO mix and colistin were analysed by flow cytometry using the fluorescent dyes 3,3-diethyloxacarbocyanine iodide(DiOC(2)(3)) to assess membrane potential, and propidium iodide (PI) and SYTO9 to assess membrane integrity following treatment at the GIC and 1/2-GIC of the EO mix every h for 4 h. At 1 h, treatment with EO mix and colistin resulted in significant cell membrane alteration and depolarization. Membrane integrity measurements identified four sub-populations that were not distributed in the same way between EO mix and antibiotic treated cells. Colistin at GIC and 1/2-GIC drastically disintegrated the cells that appeared as debris (69.8% of cells were lysed after 1 h of treatment) whereas the EO mix at GIC altered membrane of a majority of cells (67.4 +/- 1.3% of cells were partially altered). Contact with 1/2-GIC EO mix led to sub-populations that persisted or recovered a physiological state with intact membrane (from 1 h to 4 h of treatment, intact cells increased from 23 to 33%). So, it was demonstrated that the EO mix presented antibacterial action against E. coli. It altered membrane properties by decreasing its polarity and integrity which were reversible phenomena here

Un AMI (Anti-Méthanogène Indice) qui veut du bien à votre prairie

National audienceA simple antimethanogenic index (AMI) was developped to characterize the plants growing in the meadows and the neighbouring environments. The purpose of the AMI is to evaluate the potential of a plant species to reduce methane emissions by grazing ruminants, while taking into account its energy value. The AMI was built from in vitro rumen fermentation data obtained from a set of 212 plants used as pure substrates. The AMI could be seen as the deviation between measured methane production and its theoretical value coming from the regression between methane and volatile fatty acid (VFA) productions. The plants were then classified into three groups : 44 plants that activated methanogenesis (AMI 0). The strongest effect was observed with Bidens tripartita (AMI = 1) and numerous other plants had a promising positive AMI, including Origanum vulgare (0.61), Scrophularia nodosa (0.56), Serratula tinctoria (0.49), Succisa pratensis (0.19), Polygonum bistorta (0.17) and Hypericum perforatum (0.16). The anti-methanogenic effect did not seem to be carried by some plants families but rather individually by particular plants. AMI was able to classify plants according to their antimethanogenic potential. AMI findings also highlight the importance of keeping certain species in the meadow. Once a meadow’s botanical composition is known, the AMI could be included in the criteria used to evaluate its environmental potential and bring new information on the multiple services provided by pasture. The couple VFA-AMI understood as (recovered energy, lost energy) could be used to characterize fermentation of plants and opens up prospects for an energy diagnosis of the meadow.Un indice anti-méthanogène (AMI) simple a été développé pour caractériser les plantes de la prairie et de son proche environnement. L’objectif était d’évaluer le potentiel d’une plante pour réduire les émissions de méthane chez les ruminants, en tenant compte de sa valeur nutritionnelle. L’indice a été construit à partir de données obtenues in vitro par fermentation de 212 espèces de plantes utilisées comme substrat pur dans l’écosystème ruminal. Son principe repose sur la déviation observée entre la production de méthane mesurée et la valeur théorique calculée par la régression entre les productions de méthane et d’acides gras volatils (AGV), plantes atypiques exclues. Les plantes ont été classées en 3 groupes : 44 ont activé la méthanogénèse (AMI 0). L’effet le plus important a été observé avec Bidens tripartita (AMI = 1), mais nombre de plantes ont obtenu des valeurs d’AMI positives prometteuses comme par exemple : Origanum vulgare (0.61), Scrophularia nodosa (0.56), Serratula tinctoria (0.49), Succisa pratensis (0.19), Polygonum bistorta (0.17) et Hypericum perforatum (0.16). L’effet anti-méthanogène ne semblait pas porté par des familles particulières de plantes, mais plutôt individuellement par certaines espèces. L’AMI a permis de classer les plantes selon leur potentiel anti-méthanogène. Il souligne l’importance de conserver certaines espèces dans la prairie. Il pourrait aussi contribuer à l’estimation d’une valeur environnementale des prairies à partir de leur composition botanique. Le double critère AGV-AMI permet de caractériser une plante par le couple (énergie récupérée, énergie perdue) et ouvre des perspectives vers un diagnostic énergétique de la prairie