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Live biotherapeutic products constitute an emerging therapeutic approach to prevent or treat inflammatory bowel diseases. Lactobacillus acidophilus is a constituent of the human microbiota with probiotic potential, that is illustrated by improvement of intestinal inflammation and antimicrobial activity against several pathogens. In this study, we evaluated the immunomodulatory properties of the L. acidophilus strain BIO5768 at steady state and upon acute inflammation. Supplementation of naïve mice with BIO5768 heightened the transcript level of some IL-17 target genes encoding for protein with microbicidal activity independently of NOD2 signaling. Of these, the BIO5768-induced expression of Angiogenin-4 was blunted in monocolonized mice that are deficient for the receptor of IL-17 (but not for NOD2). Interestingly, priming of bone marrow derived dendritic cells by BIO5768 enhanced their ability to support the secretion of IL-17 by CD4+ T cells. Equally of importance, the production of IL-22 by type 3 innate lymphoid cells is concomitantly heightened in response to BIO5768. When administered alone or in combination with Bifidobacterium animalis spp. lactis BIO5764 and Limosilactobacillus reuteri, BIO5768 was able to alleviate at least partially intestinal inflammation induced by Citrobacter rodentium infection. Furthermore, BIO5768 was also able to improve colitis induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS). In conclusion, we identify a new potential probiotic strain for the management of inflammatory bowel diseases, and provide some insights into its IL-17-dependent and independent mode of action. [ABSTRACT FROM AUTHOR]

Propionibacterium freudenreichii is a beneficial bacterium widely used in food as a probiotic and as a cheese-ripening starter. In these different applications, it is produced, dried, and stored before being used. Both freeze-drying and spray-drying were considered for this purpose. Freeze-drying is a discontinuous process that is energy-consuming but that allows high cell survival. Spray-drying is a continuous process that is more energy-efficient but that can lead to massive bacterial death related to heat, osmotic, and oxidative stresses. We have shown that P. freudenreichii cultivated in hyperconcentrated rich media can be spray-dried with limited bacterial death. However, the general stress tolerance conferred by this hyperosmotic constraint remained a black box. In this study, we modulated P. freudenreichii growth conditions and monitored both osmoprotectant accumulation and stress tolerance acquisition. Changing the ratio between the carbohydrates provided and non-protein nitrogen during growth under osmotic constraint modulated osmoprotectant accumulation. This, in turn, was correlated with P. freudenreichii tolerance towards different stresses, on the one hand, and towards freeze-drying and spray-drying, on the other. Surprisingly, trehalose accumulation correlated with spray-drying survival and glycine betaine accumulation with freeze-drying. This first report showing the ability to modulate the trehalose/GB ratio in osmoprotectants accumulated by a probiotic bacterium opens new perspectives for the optimization of probiotics production. [ABSTRACT FROM AUTHOR]

Crohn's disease is linked to a decreased diversity in gut microbiota composition as a potential consequence of an impaired anti-microbial response and an altered polarization of T helper cells. Here, we evaluated the immunomodulatory properties of two potential probiotic strains, namely a Bifidobacterium animalis spp. lactis Bl 5764 and a Lactobacillus reuteri Lr 5454 strains. Both strains improved colitis triggered by either 2,4,6-trinitrobenzenesulfonic acid (TNBS) or Citrobacter rodentium infection in mice. Training of dendritic cells (DC) with Lr 5454 efficiently triggered IL-22 secretion and regulatory T cells induction in vitro, while IL-17A production by CD4+ T lymphocytes was stronger when cultured with DCs that were primed with Bl 5764. This strain was sufficient for significantly inducing expression of antimicrobial peptides in vivo through the Crohn's disease predisposing gene encoding for the nucleotide-binding oligomerization domain, containing protein 2 (NOD2). In contrast, NOD2 was dispensable for the impact on antimicrobial peptide expression in mice that were monocolonized with Lr 5454. In conclusion, our work highlights a differential mode of action of two potential probiotic strains that protect mice against colitis, providing the rational for a personalized supportive preventive therapy by probiotics for individuals that are genetically predisposed to Crohn's disease. [ABSTRACT FROM AUTHOR]

Labelled leucocyte scintigraphy (LS) is regarded as helpful when exploring bone and joint infections. The aim of this study was to evaluate the utility of LS for the diagnosis of chronic periprosthetic joint infections (PJIs) in patients exhibiting arthroplastic loosening. One hundred sixty-eight patients were referred to centres for treatment of complex PJI. One hundred fifty underwent LS using 99mTc-HMPAO (LLS); 18 also underwent anti-granulocyte scintigraphy (AGS) and 13 additional SPECT with tomodensitometry imaging (SPECT-CT). The LS results were compared with bone scan data. For all, the final diagnoses were determined microbiologically; perioperative samples were cultured. LS values were examined, as well as sensitivity by microorganism, anatomical sites, and injected activity. LS results were also evaluated according to the current use of antibiotics or not. The sensitivity, specificity, and positive predictive value of LLS were 72%, 60%, and 80%, respectively. LLS performed better than did AGS. SPECT-CT revealed the accurate locations of infections. The sensitivity of LS was not significantly affected by the causative pathogen or the injected activity. No correlation was evident between the current antibiotic treatment and the LS value. The test was more sensitive for knee (84%) than hip arthroplasty (57%) but was less specific for knee (52% vs. 75%). Sensitivity and specificity of LLS varied by the location of infection bone scan provide no additional value in PJI diagnosis. Current antibiotic treatment seems to have no influence on LS sensitivity as well as labelling leukocyte activity or pathogens responsible for chronic PJI. [ABSTRACT FROM AUTHOR]

The use of the subsurface for CO storage, geothermal energy generation, and nuclear waste disposal will greatly increase the interaction between clay(stone) and concrete. The development of models describing the mineralogical transformations at this interface is complicated, because contrasting geochemical conditions (Eh, pH, solution composition, etc.) induce steep concentration gradients and a high mineral reactivity. Due to the complexity of the problem, analytical solutions are not available to verify code accuracy, rendering code intercomparisons as the most efficient method for assessing code capabilities and for building confidence in the used model. A benchmark problem was established for tackling this issue. We summarize three scenarios with increasing geochemical complexity in this paper. The processes considered in the simulations are diffusion-controlled transport in saturated media under isothermal conditions, cation exchange reactions, and both local equilibrium and kinetically controlled mineral dissolution-precipitation reactions. No update of the pore diffusion coefficient as a function of porosity changes was considered. Seven international teams participated in this benchmarking exercise. The reactive transport codes used (TOUGHREACT, PHREEQC, with two different ways of handling transport, CRUNCH, HYTEC, ORCHESTRA, MIN3P-THCm) gave very similar patterns in terms of predicted solute concentrations and mineral distributions. Some differences linked to the considered activity models were observed, but they do not bias the general system evolution. The benchmarking exercise thus demonstrates that a reactive transport modelling specification for long-term performance assessment can be consistently addressed by multiple simulators. [ABSTRACT FROM AUTHOR]

Soil systems are a common receptor of anthropogenic mercury (Hg) contamination. Soils play an important role in the containment or dispersion of pollution to surface water, groundwater or the atmosphere. A one-dimensional model for simulating Hg fate and transport for variably saturated and transient flow conditions is presented. The model is developed using the HP1 code, which couples HYDRUS-1D for the water flow and solute transport to PHREEQC for geochemical reactions. The main processes included are Hg aqueous speciation and complexation, sorption to soil organic matter, dissolution of cinnabar and liquid Hg, and Hg reduction and volatilization. Processes such as atmospheric wet and dry deposition, vegetation litter fall and uptake are neglected because they are less relevant in the case of high Hg concentrations resulting from anthropogenic activities. A test case is presented, assuming a hypothetical sandy soil profile and a simulation time frame of 50 years of daily atmospheric inputs. Mercury fate and transport are simulated for three different sources of Hg (cinnabar, residual liquid mercury or aqueous mercuric chloride), as well as for combinations of these sources. Results are presented and discussed with focus on Hg volatilization to the atmosphere, Hg leaching at the bottom of the soil profile and the remaining Hg in or below the initially contaminated soil layer. In the test case, Hg volatilization was negligible because the reduction of Hg to Hg was inhibited by the low concentration of dissolved Hg. Hg leaching was mainly caused by complexation of Hg with thiol groups of dissolved organic matter, because in the geochemical model used, this reaction only had a higher equilibrium constant than the sorption reactions. Immobilization of Hg in the initially polluted horizon was enhanced by Hg sorption onto humic and fulvic acids (which are more abundant than thiols). Potential benefits of the model for risk management and remediation of contaminated sites are discussed. [ABSTRACT FROM AUTHOR]

In the context of the deep waste disposal, we have investigated the respective stabilities of two iron-bearing clay minerals: berthierine ISGS from Illinois [USA; (AlFeIIIFeIIMgLiMn)(SiAl)O(OH)] and chlorite CCa-2 from Flagstaff Hill, California [USA; (SiAl)(AlFeIIIMgFeIIMnCa)O(OH)]. For berthierine, the complete thermodynamic dataset was determined at 1 bar and from 2 to 310 K, using calorimetric methods. The standard enthalpies of formation were obtained by solution-reaction calorimetry at 298.15 K, and the heat capacities were measured by heat-pulse calorimetry. For chlorite, the standard enthalpy of formation is measured by solution-reaction calorimetry at 298.15 K. This is completing the entropy and heat capacity obtained previously by Gailhanou et al. (Geochim Cosmochim Acta 73:4738-4749, ) between 2 and 520 K, by using low-temperature adiabatic calorimetry and differential scanning calorimetry. For both minerals, the standard entropies and the Gibbs free energies of formation at 298.15 K were then calculated. An assessment of the measured properties could be carried out with respect to literature data. Eventually, the thermodynamic dataset allowed realizing theoretical calculations concerning the berthierine to chlorite transition. The latter showed that, from a thermodynamic viewpoint, the main factor controlling this transition is probably the composition of the berthierine and chlorite minerals and the nature of the secondary minerals rather than temperature. [ABSTRACT FROM AUTHOR]

Aesthetics of external concrete walls can be altered in various constructions by fast developing algae and it is useful to propose technical solutions to prevent this problem. Laboratory tests are thus necessary, on the one hand to accelerate the growth of algae on concrete and, on the other, to quantify such growths. The first part of this article was dedicated to the description of two growth tests. This second part presents the advantages and drawbacks of three complementary techniques used to analyze the colonized areas. Two methods are non-destructive and estimate either the area covered, using image analysis, or the density of algae, which directly influences the stain intensity, by spectrophotometry. The third method is destructive and is based on the measurement of chlorophyll a. It is used to obtain information on the state of vitality of the algae on the colonized surface. [ABSTRACT FROM AUTHOR]

The development of biological stains has a great influence on the durability of building materials. For common concrete structures, the main and most rapid disorder linked with this development is aesthetic. In recent years, architects have been increasingly using formwork surfaces for external walls, so the search for aesthetic quality and durability has become as important as the search for mechanical quality and durability. Hence, there is a demand from industry for the qualification of concrete wall surface behaviour toward biological growths. This paper aims to itemize the various biological stains affecting concrete and to put forward two accelerated tests for the growth of algae, the organisms responsible for the first visible stains. These tests enable a wall surface to be qualified with respect to biological stains. [ABSTRACT FROM AUTHOR]

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Objective. To evaluate the impact of an intensive care unit (ICU) antibiotic-use policy on the microbial resistance in nosocomial infections and costs. Design. Comparative study before and after policy implementation. Settings. An eleven-bed ICU in a general hospital. Patients. All patients admitted for at least 48 h during a 5year period (1994–1998). Interventions. In 1995, implementation of an antibiotic-use policy. Measurements and main results. Patients' general characteristics, incidence of nosocomial infections, antibiotic-selective pressure (the number of days of antibiotic treatment for 1,000 days of presence in the ICU), presence and types of multi-resistant micro-organisms and costs linked to antibiotic use were recorded before (1994) and after implementation of the policy (1995–1998). For each year, patients' general characteristics and the incidence of nosocomial infections were the same. Costs linked to antibiotics use showed a progressive reduction (100% for 1994, 81% for 1995, 65% for 1998). Antibiotic-selective pressure diminished (from 940 days of antibiotic use per 1,000 days (1994) to 610 (1998), p<10–5). A statistically significant reduction in nosocomial infections due to antimicrobial resistant micro-organisms was observed (from 37% (1994) to 15% (1998) of nosocomial infections, p<10–5) after 3 years of implementation of the policy, essentially due to a reduction in methicillin-resistant Staphylococcus aureus and ceftriaxone-resistant Enterobacteriaceae. Nosocomial infections due to ceftazidime-resistant Pseudomonas species or extended-spectrum ß-lactamase Enterobacteriaceae showed no reduction. Conclusions. Antibiotic-use policy allowed a reduction in antibiotic-selective pressure, costs linked to antibiotics and selective reduction of nosocomial infections due to antimicrobial resistant micro-organisms. [ABSTRACT FROM AUTHOR]

Glycerol was studied as a substrate for astaxanthin by Phaffia rhodozyma PR 190. With co-utilisation of yeast extract and peptone, the maximum specific growth rate was 0.24 ± 0.02 h−1. Astaxanthin percentage in total pigment is constant (0.78 mg/g) and its yield from glycerol is always 0.97 mg/g. The yield of biomass from glycerol alone is 0.50 ± 0.02 g/g. The specific rate of astaxanthin production versus the cell growth rate reached a maximum for an optimal specific growth rate of 0.075 h−1. For this optimal value, the maximum specific astaxanthin production rate is 0.09 ± 0.01 mg/g.h. The best astaxanthin results were : 33.7 mg/l, 0.2 mg/l.h and 1.8 mg/g yeast after a fermentation term of 168 hours. Our results suggest a strategy of astaxanthin production in fed batch culture or chemostat at a growth rate of 0.075 h−1. © Rapid Science Ltd. 1998 [ABSTRACT FROM AUTHOR]

An unsaturated fatty acid auxotroph of the oleaginous yeast Apiotrichum curvatum, named UfaM3, blocked in the conversion of stearic to oleic acid was cultivated in single-stage continuous culture. The influence of consumed carbon to nitrogen ratios (C/N ratios, g g) obtained at various dilution rates (D) on fatty acid (FA) accumulation and its profiles were studied. In continuous culture in N-limited medium a maximum FA accumulation of 45.6% (g g of dry biomass) was obtained at an optimal D of 0.049 h, recording an efficiency of substrate conversion of 0.48 g g and 0.22 g g for biomass and lipids, respectively. The quality of lipid approached cocoa butter at an optimal C/N ratio of between 20 and 30. The C/N ratio in the incoming medium was 38.5 g g with 30 g l of glucose and both C and N sources were completely consumed at a critical D of ≤ 0.07 h. The stability of the mutant was demonstrated in the steady-state conditions of the chemostat with regard to the FA composition of its lipids. [ABSTRACT FROM AUTHOR]

Survival of alginate-entrapped cells of Azospirillum lipoferum was studied during dehydration using a dry air stream and during prolonged storage at various constant water activity values (a). During the drying operation, the viability loss remained almost constant from the initial water content to 0.35 g water/g dry weight (DW) corresponding to a 98.5% water removal, strongly increased until a water content of 0.25 g/g DW and then stopped until the end of the drying operational (final a 0.18). A water content of 0.25 g/g DW (a=0.55) corresponded to the critical point of the moisture sorption isotherm curve from which water became restricted to the dry material. A high drying rate (5 g/g DW per hour) was shown to be more detrimental for cell viability than a low drying rate (1.18 g/g DW per hour). When the product was stored in a closed chamber with a regulated a (0.23), the number of living cells decreased during a short period (less than 15 days) corresponding to the product a stabilization, and then remained constant for more than 150 days. In addition, cell survival during storage was not affected by a values in the range 0-0.55. Above a=0.55, the higher the a and the storage duration, the lower the residual survival percentage. The influence of the drying and storage conditions on the cell death rate are discussed with regard to both the mechanisms generally involved in viability loss and the hydration properties of water. [ABSTRACT FROM AUTHOR]