Toxicological effects of CdSe nanocrystals on the marine diatom Phaeodactylum tricornutum: The first mass spectrometry-based proteomic approach.

In the marine environment, benthic diatoms from estuarine and coastal sediments are among the first targets of nanoparticle pollution whose potential toxicity on marine organisms is still largely unknown. It is therefore relevant to improve our knowledge of interactions between these new pollutants and microalgae, the key players in the control of marine resources. In this study, the response of P. tricornutum to CdSe nanocrystals (CdSe NPs) of 5 nm (NP5) and 12 nm (NP12) in diameter was evaluated through microscopic, physiological, biochemical and proteomic approaches. NP5 and NP12 affected cell growth but oxygen production was only slightly decreased by NP5 after 1-d incubation time. In our experimental conditions, a high CdSe NP dissolution was observed during the first day of culture, leading to Cd bioaccumulation and oxidative stress, particularly with NP12. However, after a 7-day incubation time, proteomic analysis highlighted that P. tricornutum responded to CdSe NP toxicity by regulating numerous proteins involved in protection against oxidative stress, cellular redox homeostasis, Ca2+ regulation and signalling, S-nitrosylation and S-glutathionylation processes and cell damage repair. These proteome changes allowed algae cells to regulate their intracellular ROS level in contaminated cultures. P. tricornutum was also capable to control its intracellular Cd concentration at a sufficiently low level to preserve its growth. To our knowledge, this is the first work allowing the identification of proteins differentially expressed by P. tricornutum subjected to NPs and thus the understanding of some molecular pathways involved in its cellular response to nanoparticles. SIGNIFICANCE: The microalgae play a key role in the control of marine resources. Moreover, they produce 50% of the atmospheric oxygen. CdSe NPs are extensively used in the industry of renewable energies and it is regrettably expected that these pollutants will sometime soon appear in the marine environment through surface runoff, urban effluents and rivers. Since estuarine and coastal sediments concentrate pollutants, benthic microalgae which live in superficial sediments will be among the first targets of nanoparticle pollution. Thus, it is relevant to improve our knowledge of interactions between diatoms and nanoparticles. Proteomics is a powerful tool for understanding the molecular mechanisms triggered by nanoparticle exposure, and our study is the first one to use this tool to identify proteins differentially expressed by P. tricornutum subjected to CdSe nanocrystals. This work is fundamental to improve our knowledge about the defence mechanisms developed by algae cells to counteract damage caused by CdSe NPs.

Clinical and biological characteristics of the French COBRA cohort of adult subjects with asthma.

The COhort of BRonchial obstruction and Asthma (COBRA) is a longitudinal cohort that involves 12 French academic institutions. DNA, serum samples and clinical data are collected at entry and every 6 months thereafter.Of 1080 patients with asthma recruited between 2007 and 2015, 401 had mild/moderate and 613 had severe asthma. In cross-sectional analyses, compared with patients with milder disease, patients with severe asthma had more symptoms, exacerbations, hospitalisations and visits to the emergency department during the preceding 12 months, higher numbers of blood eosinophils, and more comorbidities. More than 60% of patients with severe asthma were therapy-uncontrolled at entry, and 152 of them were being treated with omalizumab. In addition, patients with asthma who had the highest eosinophilia levels (>300/mm3) had shorter asthma duration, lower lung function, and higher rates of severe exacerbations and unacceptable asthma control than patients with lower eosinophil counts.Longitudinal analyses performed in 427 patients with asthma with at least three differential blood cell counts demonstrated that both eosinophil numbers and eosinophil increase over time were associated with the number of exacerbations occurring until the next visit and with Juniper score.Studies with the COBRA cohort will help to improve knowledge concerning the risk and biological factors associated with asthma severity and to better understand their influence on the disease trajectory.

Airway smooth muscle enlargement is associated with protease-activated receptor 2/ligand overexpression in patients with difficult-to-control severe asthma.

BACKGROUND: Asthma is a complex disease with heterogeneous features of airway inflammation and remodeling. The increase in airway smooth muscle (ASM) mass is an essential component of airway remodeling in patients with severe asthma, yet the pathobiological mechanisms and clinical outcomes associated with ASM enlargement remain elusive. OBJECTIVE: We sought to compare ASM area in control subjects and patients with mild-to-moderate or severe asthma and to identify specific clinical and pathobiological characteristics associated with ASM enlargement. METHODS: Bronchial biopsy specimens from 12 control subjects, 24 patients with mild-to-moderate asthma, and 105 patients with severe asthma were analyzed for ASM area, basement membrane thickness, vessels, eosinophils, neutrophils, T lymphocytes, mast cells, and protease-activated receptor 2 (PAR-2). In parallel, the levels of several ASM mitogenic factors, including the PAR-2 ligands, mast cell tryptase, trypsin, tissue factor, and kallikrein (KLK) 5 and KLK14, were assessed in bronchoalveolar lavage fluid. Data were correlated with asthma severity and control both at inclusion and after 12 to 18 months of optimal management and therapy. RESULTS: Analyses across ASM quartiles in patients with severe asthma demonstrated that patients with the highest ASM quartile (median value of ASM area, 26.3%) were younger (42.5 vs ≥50 years old in the other groups, P ≤ .04) and had lower asthma control after 1 year of optimal management (P ≤ .006). ASM enlargement occurred independently of features of airway inflammation and remodeling, whereas it was associated with PAR-2 overexpression and higher alveolar tryptase (P ≤ .02) and KLK14 (P ≤ .03) levels. CONCLUSION: Increase in ASM mass, possibly involving aberrant expression and activation of PAR-2-mediated pathways, characterizes younger patients with severe asthma with poor asthma control.

Mouse strain differences in metabolic fluxes and function of ex vivo working hearts.

In mice, genetic background is known to influence various parameters, including cardiac function. Its impact on cardiac energy substrate metabolism-a factor known to be closely related to function and contributes to disease development-is, however, unclear. This was examined in this study. In commonly used control mouse substrains SJL/JCrNTac, 129S6/SvEvTac, C57Bl/6J, and C57Bl/6NCrl, we assessed the functional and metabolic phenotypes of 3-mo-old working mouse hearts perfused ex vivo with physiological concentrations of (13)C-labeled carbohydrates (CHO) and a fatty acid (FA). Marked variations in various functional and metabolic flux parameters were observed among all mouse substrains, although the pattern observed differed for these parameters. For example, among all strains, C57Bl/6NCrl hearts had a greater cardiac output (+1.7-fold vs. SJL/JCrNTac and C57Bl/6J; P < 0.05), whereas at the metabolic level, 129S6/SvEvTac hearts stood out by displaying (vs. all 3 strains) a striking shift from exogenous FA (~-3.5-fold) to CHO oxidation as well as increased glycolysis (+1.7-fold) and FA incorporation into triglycerides (+2-fold). Correlation analyses revealed, however, specific linkages between 1) glycolysis, FA oxidation, and pyruvate metabolism and 2) cardiac work, oxygen consumption with heart rate, respectively. This implies that any genetically determined factors affecting a given metabolic flux parameter may impact on the associated functional parameters. Our results emphasize the importance of selecting the appropriate control strain for cardiac metabolic studies using transgenic mice, a factor that has often been neglected. Understanding the molecular mechanisms underlying the diversity of strain-specific cardiac metabolic and functional profiles, particularly the 129S6/SvEvTac, may ultimately disclose new specific metabolic targets for interventions in heart disease.

Plastids of marine phytoplankton produce bioactive pigments and lipids.

Phytoplankton is acknowledged to be a very diverse source of bioactive molecules. These compounds play physiological roles that allow cells to deal with changes of the environmental constrains. For example, the diversity of light harvesting pigments allows efficient photosynthesis at different depths in the seawater column. Identically, lipid composition of cell membranes can vary according to environmental factors. This, together with the heterogenous evolutionary origin of taxa, makes the chemical diversity of phytoplankton compounds much larger than in terrestrial plants. This contribution is dedicated to pigments and lipids synthesized within or from plastids/photosynthetic membranes. It starts with a short review of cyanobacteria and microalgae phylogeny. Then the bioactivity of pigments and lipids (anti-oxidant, anti-inflammatory, anti-mutagenic, anti-cancer, anti-obesity, anti-allergic activities, and cardio- neuro-, hepato- and photoprotective effects), alone or in combination, is detailed. To increase the cellular production of bioactive compounds, specific culture conditions may be applied (e.g., high light intensity, nitrogen starvation). Regardless of the progress made in blue biotechnologies, the production of bioactive compounds is still limited. However, some examples of large scale production are given, and perspectives are suggested in the final section.

ED-XRF: a promising method for accurate and rapid quantification of metals in a bacterial matrix.

ABSTRACTThe remediation of metal-polluted water using bacterial biofilms is a promising technology. In order to help its development, the present study aims to evaluate the feasibility to utilize XRF spectrometry for accurate and rapid measurement of metal concentrations in bacterial biofilms used in treatment plants. For that purpose, an ED-XRF spectrometer was used to measure Cd, Cu, Fe, Mn, Ni and Zn concentrations within a matrix of marine bacteria Pseudomonas fluorescens BA3SM1 and its metabolites. Contaminated and control cultures of the strain BA3SM1 were dried and crushed, then analysed by ED-XRF. The LOD value of the analysed metals was between 2.08 and 10.5 µg g-1. Metal concentrations were also measured by ICP-AES or ICP-MS to support ED-XRF results. The two techniques showed a good linear correlation with a slope of at least 0.949 and R2 of at least 0.985. These results confirm the possibility to measure metal contents by ED-XRF in bacterial matrices.

The effect of ultrasonic antifouling control on the growth and microbiota of farmed European sea bass (Dicentrarchus labrax).

Biofouling is a serious threat to marine renewable energy structures and marine aquaculture operations alike. As an alternative to toxic surface coatings, ultrasonic antifouling control has been proposed as an environmentally friendly means to reduce biofouling. However, the impact of ultrasound on fish farmed in offshore structures or in marine multi-purpose platforms, combining renewable energy production and aquaculture, has not yet been assessed. Here we study the impact of ultrasound on the growth and microbiota of farmed European sea bass (Dicentrarchus labrax) under laboratory conditions. Whereas growth and survival were not reduced by ultrasound exposure, microbiological analysis using plate counts and 16S rRNA gene based metataxonomics showed a perturbation of the gill and skin microbiota, including an increase in putative pathogenic bacteria. This warrants further research into the long-term effects of ultrasonic antifouling control on the health and wellbeing of farmed fish.

Marine aggregates in North Atlantic coast: Microbial characteristics and potential interactions with farmed Atlantic salmon (Salmo salar).

Microbial contamination of aggregates collected near an Atlantic salmon farm, in the Cherbourg roadstead, was followed monthly over one year to study the dynamics of Vibrio spp. and explore their impact on farmed fish. Salmon state of health was followed through blood and histopathological analyses. Vibrio were systematically found in aggregates with particularly high concentration in August. The Splendidus clade was strongly dominant in aggregates as well as in gills, and an increase in Vibrio diversity was observed in summer and autumn. Results did not demonstrate that aggregates directly impact the bacterial community of gills, but they suggested an aggregates-gills interaction. Gill contamination was correlated with water temperature and probably impacted by amoebae. Vibrio renipiscarius and Vibrio toranzoniae were isolated in North Atlantic for the first time. A better understanding of the interaction between marine aggregates, Vibrio spp. and fish is essential to improve salmon cage farming.

Ability of the marine bacterium Pseudomonas fluorescens BA3SM1 to counteract the toxicity of CdSe nanoparticles.

UNLABELLED: In the marine environment, bacteria from estuarine and coastal sediments are among the first targets of nanoparticle pollution; it is therefore relevant to improve the knowledge of interactions between bacteria and nanoparticles. In this work, the response of the marine bacterium Pseudomonas fluorescens BA3SM1 to CdSe nanocrystals (CdSe NPs) of 3nm (NP3) and 8nm (NP8) in diameter was evaluated through microscopic, physiological, biochemical and proteomic approaches. Transmission electron microscopy images showed that NP3 were able to penetrate the bacteria, while NP8 were highly concentrated around the cells, embedded in large exopolysaccharides. In our experimental conditions, both CdSe NP sizes induced a decrease in respiration during the stationary growth phase, while only NP8 caused growth retardation and a decrease in pyoverdine production. Proteomic analyses highlighted that the strain responded to CdSe NP toxicity by inducing various defence mechanisms such as cell aggregation, extracellular CdSe NP sequestration, effective protection against oxidative stress, modifications of envelope organization and properties, and cadmium export. In addition, BA3SM1 presented a biosorption capacity of 1.6×10(16)NP3/g dry weight and 1.7×10(15)NP8/g dry weight. This strain therefore appears as a promising agent for NP bioremediation processes. Proteomic data are available via ProteomeXchange with identifier PXD004012. BIOLOGICAL SIGNIFICANCE: To the best of our knowledge, this is the first report focussing on the effects of CdSe colloidal nanocrystals (CdSe NPs) on a marine strain of Pseudomonas fluorescens. CdSe NPs are extensively used in the industry of renewable energies and it is regrettably expected that these pollutants will sometime soon appear in the marine environment through surface runoff, urban effluents and rivers. Bacteria living in estuarine and coastal sediments will be among the first targets of these new pollutants. The pseudomonads are frequently found in these ecosystems. They are involved in several biogeochemical cycles and are known for their high resistance to pollutants. Consequently, this study focussing on the effects of CdSe NPs on the marine strain P. fluorescens BA3SM1 is highly relevant for several reasons. First, it aims at improving knowledge about the interactions between bacteria and NPs. This is fundamental to effectively use NPs against pathogenic bacteria. Secondly, in spite of CdSe NP interactions with the bacterial cells, the strain BA3SM1 can develop various strategies to counteract CdSe NP toxicity and ensure its growth. It exhibits interesting properties to sequester CdSe NPs and it retains its ability to form biofilm. The strain therefore appears as a promising agent for NP bioremediation thanks to biofiltration processes. Finally, this study shows that CdSe NPs of 8nm in diameter cause a decrease in the secretion of siderophore pyoverdine, a secondary metabolite playing a key role in microbial ecology since it drives bacterial survival and competitiveness in ecosystems. Bacteria producing effective siderophores survive better in a Fe-deficient environment where they antagonize the growth of other microbes thought iron deprivation. Furthermore, siderophores are also employed as virulence factors in human pathogenic strains such as P. aeruginosa. Consequently, this study highlights that NPs can impact the secondary metabolism of bacteria with environmental and medical implications. In addition, in this work, Data-Dependant Acquisition (DDA) provided state of the art Mass Spectrometry data by Spectral Counting and MS1 Label-Free. The combination of these two well-known proteomic techniques including manual validations strengthened the identification and quantification of regulated proteins. Moreover, numerous correlations between proteomic analyses and other observations (physiological, biochemical, microscopic) consolidated our interpretations.

Dampened Mesolimbic Dopamine Function and Signaling by Saturated but not Monounsaturated Dietary Lipids.

Overconsumption of dietary fat is increasingly linked with motivational and emotional impairments. Human and animal studies demonstrate associations between obesity and blunted reward function at the behavioral and neural level, but it is unclear to what degree such changes are a consequence of an obese state and whether they are contingent on dietary lipid class. We sought to determine the impact of prolonged ad libitum intake of diets rich in saturated or monounsaturated fat, separate from metabolic signals associated with increased adiposity, on dopamine (DA)-dependent behaviors and to identify pertinent signaling changes in the nucleus accumbens (NAc). Male rats fed a saturated (palm oil), but not an isocaloric monounsaturated (olive oil), high-fat diet exhibited decreased sensitivity to the rewarding (place preference) and locomotor-sensitizing effects of amphetamine as compared with low-fat diet controls. Blunted amphetamine action by saturated high-fat feeding was entirely independent of caloric intake, weight gain, and plasma levels of leptin, insulin, and glucose and was accompanied by biochemical and behavioral evidence of reduced D1R signaling in the NAc. Saturated high-fat feeding was also tied to protein markers of increased AMPA receptor-mediated plasticity and decreased DA transporter expression in the NAc but not to alterations in DA turnover and biosynthesis. Collectively, the results suggest that intake of saturated lipids can suppress DA signaling apart from increases in body weight and adiposity-related signals known to affect mesolimbic DA function, in part by diminishing D1 receptor signaling, and that equivalent intake of monounsaturated dietary fat protects against such changes.

The effect of cold stress on the proteome of the marine bacterium Pseudomonas fluorescens BA3SM1 and its ability to cope with metal excess.

This study examined the effect of cold stress on the proteome and metal tolerance of Pseudomonas fluorescens BA3SM1, a marine strain isolated from tidal flat sediments. When cold stress (+10 °C for 36 h) was applied before moderate metal stress (0.4 mM Cd, 0.6 mM Cd, 1.5 mM Zn, and 1.5 mM Cu), growth disturbances induced by metal, in comparison with respective controls, were reduced for Cd and Zn while they were pronounced for Cu. This marine strain was able to respond to cold stress through a number of changes in protein regulation. Analysis of the predicted differentially expressed protein functions demonstrated that some mechanisms developed under cold stress were similar to those developed in response to Cd, Zn, and Cu. Therefore, pre-cold stress could help this strain to better counteract toxicity of moderate concentrations of some metals. P. fluorescens BA3SM1 was able to remove up to 404.3 mg Cd/g dry weight, 172.5 mg Zn/g dry weight, and 11.3 mg Cu/g dry weight and its metal biosorption ability seemed to be related to the bacterial growth phase. Thus, P. fluorescens BA3SM1 appears as a promising agent for bioremediation processes, even at low temperatures.

Strategies developed by the marine bacterium Pseudomonas fluorescens BA3SM1 to resist metals: A proteome analysis.

A global proteomic evaluation of the response of the marine bacterium Pseudomonas fluorescens BA3SM1 to Cd, Zn and Cu was performed by two dimensional gel electrophoresis followed by mass spectrometry. When stressed with Cd, the most toxic metal for P. fluorescens BA3SM1, cell growth is rapidly affected and the number of proteins up-regulated (sixteen for 0.4 mM Cd) remains low in comparison with results obtained for Zn and Cu (twenty eight for 1.5mM Zn and forty four for 1.5 mM Cu). The changes in protein expression indicate that the cell adapts to metals by inducing essentially seven defense mechanisms: cell aggregation/biofilm formation (Zn=Cu>Cd); modification of envelope properties to increase the extracellular metal biosorption and/or control the uptake of metal (Cu>Zn); metal export (Cd=Zn and probably Cu); responses to oxidative stress (Cu>Zn>Cd); intracellular metal sequestration (Zn=Cu and probably Cd); hydrolysis of abnormally folded proteins (Cd=Cu), and the over-synthesis of proteins inhibited by metal (Cd>Cu>Zn). To the best of our knowledge, this is the first report showing that a marine P. fluorescens is able to acquire a metal-resistant phenotype, making the strain BA3SM1 a promising agent for bioremediation processes.

Plasma brain natriuretic peptide and cardiac troponin I concentrations after adult cardiac surgery: association with postoperative cardiac dysfunction and 1-year mortality.

OBJECTIVE: The purpose of the present study was to evaluate the prognostic implications of perioperative B-type natriuretic peptide (BNP) and cardiac troponin I concentrations in patients undergoing cardiopulmonary bypass for cardiac surgery. DESIGN: Prospective observational study. SETTING: Biochemistry laboratory and surgical care unit in a university hospital. PATIENTS: A total of 92 consecutive patients undergoing elective coronary artery (43 patients) or valve surgery (49 patients). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: BNP and cardiac troponin I concentrations were measured before surgery (day 0), and at day 1 after surgery. Postoperative cardiac dysfunction was defined as low cardiac output or hemodynamic instability requiring inotropic support for >24 hrs or congestive heart failure until day 5. One-year survival was also evaluated. Univariate and multivariate analyses were performed. An important BNP secretion was systematically observed after cardiac surgery. Independent predictors of cardiac dysfunction were preoperative New York Health Association class and BNP and cardiac troponin I concentrations measured at day 1. Patients with an elevation of both markers have a 12-fold increased risk of postoperative heart failure. The use of both markers in combination predicted better postoperative heart failure than each one separately. Age, low preoperative left ventricular ejection fraction, and elevated BNP at day 1 (>352 pg/mL) were associated with an increased mortality rate at 1 yr. In multivariate analysis, only left ventricular ejection fraction was significantly associated with 1-yr survival. CONCLUSIONS: Postoperative plasma BNP and cardiac troponin I levels are independent predictors of postoperative cardiac dysfunction after cardiac surgery. Simultaneous measurement of BNP and cardiac troponin I improve the risk assessment of postoperative cardiac dysfunction. However, the association between BNP levels and 1-yr outcome was no longer significant after adjustment on left ventricular ejection fraction.