We have cloned and expressed in
Escherichia coli a 702-base pair gene coding for the dihydrofolate reductase (DHFR) domain of the bifunctional dihydrofolate reductase-thymidylate synthase (DHFR-TS) ...from
Trypanosoma cruzi. The DHFR domain was purified to homogeneity by methotrexate-Sepharose chromatography followed by an anion-exchange chromatography step in a mono Q column, and displayed a single 27-kDa band on SDS-PAGE. Gel filtration showed that the catalytic domain was expressed as a monomer. Kinetic parameters were similar to those reported for the wild-type bifunctional enzyme with
K
m values of 0.75 μM for dihydrofolate and 16 μM for NADPH and a
k
cat value of 16.5 s
−1.
T. cruzi DHFR is poorly inhibited by trimethoprim and pyrimethamine and the inhibition constants were always lower for the bifunctional enzyme. The binding of methotrexate was characteristic of a class of inhibitors that form an initial complex which isomerizes slowly to a tighter complex and are referred to as ‘slow, tight-binding’ inhibitors. While the slow-binding step of inhibition was apparently unaffected in the individually expressed DHFR domain, the overall inhibition constant was two-fold higher as a consequence of the superior inhibition constant value obtained for the initial inhibitory complex.
The success of the e-learning paradigm observed in recent times has created a growing demand for e-learning systems in universities and other educational institutions, which has itself led to the ...development of a number of either commercial or open-source Learning Management Systems (LMS). While the usage of these systems gains recognition and acceptance amongst institutions, there are new problems arising that need to be solved. Because of multiplicity of platforms and approaches for systems implementation, it becomes increasingly difficult to manage or compare them. Each new LMS presents its own learning model. How to compare different e-learning platforms, and on what basis to choose the most adequate one, is a task of ever increasing importance. This paper describes and compares some widely used open-source e-learning platforms (Docebo, Moodle, Dokeos, Claroline, Atutor and Ilias) from the point of their adaptivity.
This paper deals with the application of adaptive signal models for parametric audio coding. The matching pursuit algorithm is used for extracting sinusoidal components and transients in audio ...signals. The resulting residue is perceptually modelled as a noise like signal. First of all, an accurate detection of transients in audio signals is required. When a transient is detected, psychoacoustic-adapted matching pursuits are accomplished using a wavelet-based dictionary followed of an harmonic one. Otherwise, matching pursuit is applied only to the harmonic dictionary. This multi-part model (Sines + Transients + Noise) is successfully applied for audio coding purposes, assuring high perceptual audio quality at low bit rates (lower than 24 kbps for most of the CD-quality one channel audio signals considered for testing).
The binding of 5‐fluoro‐2′‐deoxyuridine 5′‐monophosphate (FdUMP) to Lactobacillus casei recombinant thymidylate synthase has been studied by isothermal titration microcalorimetry at pH 7.1 over the ...temperature range 16–35°C. Calorimetric measurements in various buffer systems with different heats of ionization suggest that a proton uptake is involved in the binding process of the nucleotide. In the temperature range investigated, the mol protons bound/mol nucleotide increases as the temperature decreases.
A model of two equal and independent sites fits well with the binding isotherms for thymidylate synthase. The binding constants, the changes in Gibbs energy, enthalpy, and entropy/site for FdUMP binding were calculated at each temperature. The results show that the binding is driven by both enthalpy and entropy contributions in the range 16–35°C. The enthalpy changes become more negative as the temperature increases, with CP=–170±20 J K1 (mol FdUMP bound)−1. The behavior of the system supports the observation that FdUMP binds to thymidylate synthase without producing profound conformational changes in the protein dimer.
In an acute assay, rats fasted for 24 h were sounded with 2 ml of fresh yogurt, sterilised yogurt or distilled water, and sacrificed at 2, 4, 8 and 24 h. They were compared with non-sounded rats. The ...survival of the lactic bacteria of the yogurt administered in the animals' stomach and intestines was determined, and the bacteria isolated were to the Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus profiles belonging to the strains isolated originally from the yogurt. Counts of the total number of microorganisms that were grown in lactobacilli and lactic streptococci media were also made. Analyses of the different types of resulting colonies in the lactobacilli and lactic streptococci media was performed. No L. delbrueckii subsp. bulgaricus or S. thermophilus were characterized in this acute assay. The statistical analysis of the results did not show significant differences in the log UFC. g-1, of the intestinal microbiota microorganisms of the three groups of animals in any of the times. In a chronic assay, three groups of animals, after 30 days of nourishment ad libitum with either a semisynthetic diet with 10% of fresh yogurt, or with 10% of sterilised yogurt or controls, housed in individual metabolism cells, were sacrificed. The results did not show meaningful differences in the long UFC. g-1 of the intestinal microbiota microorganisms from the three groups of animals in any of the times. In turn, in the study of the different types of colonies resulting in the lactobacilli and lactic streptococci media, no L. delbrueckii subsp. bulgaricus or S. thermophilus were characterised in this chronic assay. The results did not show meaningful differences in the log CFU. g-1 of the intestinal flora microorganisms from the three groups of animals in any of the times. In turn, no L. delbrueckii subsp. bulgaricus or S. thermophilus were characterised in this chronic assay.
A novel strategy based on solar photo-Fenton mediated by ferric nitrilotriacetate (Fe3+-NTA) combined with NaOCl in continuous flow mode for wastewater reclamation has been studied. Escherichia coli ...(E. coli) inactivation attained ≥ 5 log10-units, meeting the most restrictive EU 2020/741 target (10 CFU/100 mL), and 75% of organic microcontaminant total load was removed. As a remarkable finding, trihalomethanes (THMs) concentration was insignificant, complying by far with the Italian legislation limit. To attain these results, first the effect of liquid depth on E. coli inactivation and imidacloprid (IMD) removal from spiked municipal effluents was evaluated in continuous flow pilot-scale raceway pond reactors at 60-min hydraulic residence time with low reagent concentrations (0.10 mM Fe3+-NTA, 0.73 mM H2O2 and 0.13 mM NaOCl). Disinfection was due to the bactericidal effect of chlorine. In contrast, liquid depth notably influenced microcontaminant removal, highlighting that operation at 10-cm liquid depth allows achieving treatment capacities higher than at 5 cm (16.50 vs 28.20 mg IMD/m2∙day). Next, the monitoring of THMs was carried out to evaluate the generation and degradation of disinfection by-products, along with the removal of actual microcontaminants. These promising results draw attention to the treatment potential and open the way for its commercial application.
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•Continuous flow operation of solar photo-Fenton combined with NaOCl was assessed.•Liquid depth affected microcontaminant removal; disinfection was due to NaOCl.•> 75% microcontaminants were removed in 10-cm deep reactor at 60 min of HRT.•E. coli inactivation was ≥ 5 log-units meeting EU 2020/741 target.•Trihalomethanes’ concentration was 7.5–10 fold below the mandatory limit regulated.
One anastomosis gastric bypass (OAGB) is increasingly used in the treatment of morbid obesity. However, the efficacy and safety outcomes of this procedure remain debated. We report the results of a ...randomised trial (YOMEGA) comparing the outcomes of OAGB versus standard Roux-en-Y gastric bypass (RYGB).
This prospective, multicentre, randomised non-inferiority trial, was held in nine obesity centres in France. Patients were eligible for inclusion if their body-mass index (BMI) was 40 kg/m2 or higher, or 35 kg/m2 or higher with the presence of at least one comorbidity (type 2 diabetes, high blood pressure, obstructive sleep apnoea, dyslipidaemia, or arthritis), and were aged 18–65 years. Key exclusion criteria were a history of oesophagitis, Barrett's oesophagus, severe gastro-oesophageal reflux disease resistant to proton-pump inhibitors, and previous bariatric surgery. Participants were randomly assigned (1:1) to OAGB or RYGB, stratified by centre with blocks of variable size; the study was open-label, with no masking required. RYGB consisted of a 150 cm alimentary limb and a 50 cm biliary limb and OAGB of a single gastrojejunal anastomosis with a 200 cm biliopancreatic limb. The primary endpoint was percentage excess BMI loss at 2 years. The primary endpoint was assessed in the per-protocol population and safety was assessed in all randomised participants. This study is registered with ClinicalTrials.gov, number NCT02139813, and is now completed.
From May 13, 2014, to March 2, 2016, of 261 patients screened for eligibility, 253 (97%) were randomly assigned to OAGB (n=129) or RYGB (n=124). Five patients did not undergo their assigned surgery, and after undergoing their surgery 14 were excluded from the per-protocol analysis (seven due to pregnancy, two deaths, one withdrawal, and four revisions from OAGB to RYGB) In the per-protocol population (n=117 OAGB, n=117 RYGB), mean age was 43·5 years (SD 10·8), mean BMI was 43·9 kg/m2 (SD 5·6), 176 (75%) of 234 participants were female, and 58 (27%) of 211 with available data had type 2 diabetes. After 2 years, mean percentage excess BMI loss was −87·9% (SD 23·6) in the OAGB group and −85·8% (SD 23·1) in the RYGB group, confirming non-inferiority of OAGB (mean difference −3·3%, 95% CI −9·1 to 2·6). 66 serious adverse events associated with surgery were reported (24 in the RYGB group vs 42 in the OAGB group; p=0·042), of which nine (21·4%) in the OAGB group were nutritional complications versus none in the RYGB group (p=0·0034).
OAGB is not inferior to RYGB regarding weight loss and metabolic improvement at 2 years. Higher incidences of diarrhoea, steatorrhoea, and nutritional adverse events were observed with a 200 cm biliopancreatic limb OAGB, suggesting a malabsorptive effect.
French Ministry of Health.
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