Introduction and PCR detection of Desulfomonile tiedjei in soil slurry microcosms

The aim of this work was to test the feasibility ofintroducing an anaerobic microbial reductivedechlorination activity into non sterile soil slurrymicrocosms by inoculation with the pure anaerobicbacterial strain Desulfomonile tiedjei, which iscapable of dechlorinating 3-chlorobenzoate tobenzoate. To show that the bacterium was establishedin the microcosms we followed the expression of thereductive dechlorination activity and a molecularprobe based on PCR amplification of the 16S rDNA genewas developed. However, the success of PCRamplification of the 16S rDNA gene depends on the DNAextraction and purification methodologies applied, asshown through the use of several protocols. In thisstudy we report a DNA extraction and purificationmethod which generates sufficient and very clean DNAsuitable for PCR amplification of the D. tiedjei16S rDNA gene. The threshold of detection was about5.10³ bacteria per gram of soil slurry.Introduction of D. tiedjei in soil slurrymicrocosms proved successful since 3-chlorobenzoatedechlorination activity was established with thisbacterium in microcosms normally devoid of thisdechlorination capacity. Indeed, the addition of D. tiedjei to microcosms supplemented with acetateplus formate as cosubstrate, at their respectiveconcentrations of 5 and 6 mM, led to a totalbiotransformation of 2.5 mM of 3-chlorobenzoate within12 days. After complete 3-chlorobenzoatedechlorination, the 16S rDNA gene of this bacteriumwas specifically detected only in the inoculatedmicrocosms as shown by PCR amplification followed byrestriction mapping confirmation.     

Gas-phase methyl ethyl ketone biodegradation in a tubular biofilm reactor: microbiological and bioprocess aspects

A novel type of bioreactor was designed to clean VOCs-containing air.The operation of this reactor consists in mixing the polluted gas and a mistof nutrient solution in the presence of microorganisms in order to maximizecontact and transfer between gas, liquid and microorganisms and to promotethe degradation kinetics and the relative removal efficiency of thepollutant. A bacterial consortium acclimatized to MEK and containing apreponderance of Alcaligenes denitrificans was established under non-axenicconditions. On the tubular reactor's glass walls, a continuous biofilm wasdeveloped. This biofilm was rapidly contaminated by two fungi able todegrade MEK: Geotrichum candidum and Fusarium oxysporum. Their abundance inthe reactor is probably linked to the acidic conditions inside the biofilmand to their broader tolerance for low pH values concomitant with MEKdegradation. In the reactor, a maximum volumetric degradation rate of 3.5 kgMEK/m³ _reactor·d was obtained for arelative removal efficiency of 35%, whereas the latter was maintainedat 70% for more modest applied loadings of 1.5 kgMEK/m³ _reactor ·d. In liquid batchcultures, a biomass originating from the biofilm was able to degrade 0.40g_MEK/g_DCW·h at the optimal pH of 7. Aregular cycle of detachment-recolonization was observed during the operationof the bioreactor. The maximal degradation activity was obtained with a thinbiofilm and was not increased as the biofilm grew in thickness. The overalldegradation rate of the process did not appear to be limited by thediffusion of oxygen inside the biofilm. Over short periods of time, the MEKtransfer from the gaseous phase to the biofilm was neither affected by thepresence of the mist nor by the wetting of the biofilm. A better control ofthe biofilm pH led to improved performance in terms of removal rate but notin terms of relative elimination efficiency.     

Energy conversion in an internally illuminated annular‐plate airlift photobioreactor

Algal‐derived therapeutics, bioactive molecules, and fuels produced in photobioreactors (PBRs) are of great scientific and economic interest, but the high cost of production still prevents their widespread use. Specifically, the cost of the energy inputs and the control of the photonic inputs that enable production optimization continue to be problematic. To this end, a novel 55‐L annular‐plate airlift PBR (APAPBR) with internal illumination was designed and characterized for the batch production of algal biomass. The APAPBR was able to convert mixing and photonic energy inputs into Chlorella pituita SG1 biomass at an efficiency of 0.064 (J biomass [J input]^?1), or 0.27 g dry cell weight (DW) W^?1 d^?1. Thanks to a high degree of photon capture and the airlift effect that provided energy‐efficient mixing and mass transfer, this energy conversion is 54% of the theoretical maximum as determined in previous studies. Under these efficiency conditions, C. pituita SG1 was able to grow photoautotrophically to 3.9 ± 0.2 gDW L^?1. Additionally, a mathematical approach was used to predict the mean light intensity with the highest biomass yield per unit of photonic input and the maximum biomass concentration achievable under the given process conditions. These predictions were validated in our system by the experimental cultivation data. This APAPBR represents a simple, innovative, and energy‐efficient PBR configuration that could decrease the cost of phototrophic bioprocesses and enable novel bioprocesses that require a high degree of control over the photonic input.     

The 5-HT1A receptor agonist buspirone improves esophageal motor function and symptoms in systemic sclerosis: a 4-week,open-label trial

BackgroundAcute administration of the oral 5-HT₁A receptor agonist buspirone, which is commonly used as an anxiolytic drug, may improve compromised lower esophageal sphincter function. In an open-label trial we assessed the effects of buspirone on esophageal motor function and symptoms in patients with esophageal involvement associated with systemic sclerosis (SSc).MethodsThirty consecutive patients with SSc and symptomatic esophageal involvement, despite treatment with proton pump inhibitors, underwent high resolution manometry and chest computed tomography for assessment of motor function and esophageal dilatation, respectively. Regurgitation, heartburn, dysphagia, and chest pain severity was subjectively scored by visual analog scales. Manometric parameters (primary endpoint) and symptom severity (secondary endpoint) were re-examined after 4-week daily administration of 20 mg buspirone. Other medications remained unchanged.ResultsEight patients did not complete the trial because of buspirone-associated dizziness (n = 2), or nausea (n = 2), or reluctancy to undergo final manometry. In the remaining 22 patients lower esophageal sphincter (LES) resting pressure increased from 7.7 ± 3.9 to 12.2 ± 4.6 mmHg (p = 0.00002) after buspirone administration; other manometric parameters did not change. Statistical analysis revealed negative correlation between individual increases in resting LES pressure and supra-aortic esophageal diameter (r = -0.589, p = 0.017), suggesting a more beneficial effect in patients with less severely affected esophageal function. Heartburn and regurgitation scores decreased at 4 weeks compared to baseline (p = 0.001, and p = 0.022, respectively).ConclusionOur findings warrant more conclusive evaluation with a double-blind controlled study; however, buspirone could potentially be given under observation for objective improvement in all patients with SSc who report reflux symptoms despite undergoing standard treatment.

Trial registration

ClinicalTrials.gov Identifier: {"type":"clinical-trial","attrs":{"text":"NCT02363478","term_id":"NCT02363478"}}NCT02363478 Registered: 21-02-2014.     

Lactic acid bacteria population dynamics during spontaneous fermentation of radish (<Emphasis Type="Italic">Raphanus sativus</Emphasis> L.) roots in brine

The aim of the present study was to assess the microecosystem development and the dynamics of the lactic acid bacteria population during spontaneous fermentation of radish (Raphanus sativus L.) roots in brine at 20 and 30?°C. In both temperatures, lactic acid bacteria prevailed the fermentation; as a result, the pH value was reduced to ca. 3.6 and total titrable acidity increased to ca. 0.4% lactic acid. Enterococci population increased and formed a secondary microbiota while pseudomonads, Enterobacteriaceae and yeasts/molds populations were below enumeration limit already before the middle of fermentation. Pediococcus pentosaceus dominated during the first days, followed by Lactobacillus plantarum that prevailed the fermentation until the end. Lactobacillus brevis was also detected during the final days of fermentation. A succession at sub-species level was revealed by the combination of RAPD-PCR and rep-PCR analyses. Glucose and fructose were the main carbohydrates detected in brine and were metabolized into lactic acid, acetic acid and ethanol.     

Rapid and synchronous chemical induction of replicative-like senescence via a small molecule inhibitor

Cellular senescence is acknowledged as a key contributor to organismal ageing and late-life disease. Though popular, the study of senescence in vitro can be complicated by the prolonged and asynchronous timing of cells committing to it and by its paracrine effects. To address these issues, we repurposed a small molecule inhibitor, inflachromene (ICM), to induce senescence to human primary cells. Within 6 days of treatment with ICM, senescence hallmarks, including the nuclear eviction of HMGB1 and -B2, are uniformly induced across IMR90 cell populations. By generating and comparing various high throughput datasets from ICM-induced and replicative senescence, we uncovered a high similarity of the two states. Notably though, ICM suppresses the pro-inflammatory secretome associated with senescence, thus alleviating most paracrine effects. In summary, ICM rapidly and synchronously induces a senescent-like phenotype thereby allowing the study of its core regulatory program without confounding heterogeneity.