Search results for "Clostridium"
showing 10 items of 128 documents
Optimization of alkali pretreatment to enhance rice straw conversion to butanol
2021
Abstract The use of rice straw (RS) was enhanced to produce biobutanol as biofuel, for which the NaOH pretreatment was optimized by considering the butanol-biomass ratio that quantify the mass balance efficiency of the three sequential stages of the process: pretreatment, enzymatic hydrolysis and fermentation by Clostridium beijerinckii. The optimum point (solid loading of 5% w/v with 0.75% w/v NaOH at 134 °C for 20 min) of the best cost-wise option yielded an enhanced biomass use of 77.6 g kg RS−1. A maximum butanol titer of 10.1 g L−1 was reached after 72 h of fermentation with the complete uptake of glucose and nearly complete uptake of xylose. The NaOH concentration was the most influen…
Thermophilic hydrogen production from cellulose with rumen fluid enrichment cultures: Effects of different heat treatments
2011
Elevated temperatures (52, 60 and 65 °C) were used to enrich hydrogen producers on cellulose from cow rumen fluid. Methanogens were inhibited with two different heat treatments. Hydrogen production was considerable at 60 °C with the highest H2 yield of 0.44 mol-H2 mol-hexose -1 (1.93 mol-H2 mol-hexose-degraded-1) as obtained without heat treatment and with acetate and ethanol as the main fermentation products. H2 production rates and yields were controlled by cellulose degradation that was at the highest 21%. The optimum temperature and pH for H2 production of the rumen fluid enrichment culture were 62 °C and 7.3, respectively. The enrichments at 52 and 60 °C contained mainly bacteria from …
Enzyme molecular mechanism as a starting point to design new inhibitors: a theoretical study of O-GlcNAcase.
2011
O-Glycoprotein 2-acetamino-2-deoxy-β-d-glucopyranosidase (O-GlcNAcase) hydrolyzes O-linked 2-acetamido-2-deoxy-β-d-glucopyranoside (O-GlcNAc) residues from post-translationally modified serine/threonine residues of nucleocytoplasmic protein. The chemical process involves substrate-assisted catalysis, where two aspartate residues have been identified as the two key catalytic residues of O-GlcNAcase. In this report, the first step of the catalytic mechanism used by O-GlcNAcase involving substrate-assisted catalysis has been studied using a hybrid quantum mechanical/molecular mechanical (QM/MM) Molecular Dynamics (MD) calculations. The free energy profile shows that the formation of the oxazol…
ChemInform Abstract: Polycondensed Nitrogen Heterocycles. Part 17. Isoxazolo(4,3-d)pyrazolo-(3,4-f)(1,2,3)triazepine. A New Ring System.
1988
The title compounds were prepared by nitration of compounds 2, reduction of the dinitro derivatives 4 and diazotization of the diamino derivatives 6 followed by an intramolecular coupling reaction. Compound 4a showed good activity against Salmonella cholerasuis and Clostridium perfringens bacteria.
Activation and Inactivation of Tetanus Toxin in Chromaffin Cells
1993
Tetanus toxin is produced by Clostridium tetani as a single chain, almost non-toxic, protein with a molecular weight of approximately 150.000 representing 1315 amino acids. Bacterial proteases cleave the molecule between positions A 457 and S 458 (extracellular activation), yielding a heavy chain (MW 100.000) and a light chain (MW 50.000) tetanus toxin (HC-TeTx, LC-TeTx). Both chains remain connected to each other by a disulphur bond between positions C 439 and C 467 (Dichain-TeTx)1. The cleavage or nicking dramatically increases the biological activity2. HC-TeTx is involved in binding DC-TeTx to gangliosides lodged in the plasma membrane, which is a prerequisite for incorporation into the …
A new method to value efficiency of enzyme blends for pancreatic tissue digestion.
2010
Islet transplantation, since the 90’s, has been resulting to be one of the best successful example of human cell therapy. Nevertheless, islet isolation procedure is not completely standardized; in fact, more than fifty percent of islets procedures don’t arrive to their transplantation. This is due both to the variability of donor’s pancreas and to an unpredictable enzymatic blend efficiency. Enzymes used in pancreas digestion are extracted from Clostridium histolyticum bacteria and digest several substrates. In particular they have strong collagenolytic activity compared to vertebrate collagenases. However, several impediments persist in human islet isolation success probably due to the var…
Do we Need a Triple Antibiotic Therapy?
2001
To compare the efficacy and toxicity of triple antibiotic therapy in patients undergoing autologous peripheral blood-stem-cell transplantation (PBSCT) with literature data.
Antibiotic prophylaxis for the prevention of infective endocarditis for dental procedures is not associated with fatal adverse drug reactions in Fran…
2018
Background One of the major reasons to stop antibiotic prophylaxis (AP) to prevent infective endocarditis (IE) in the United Kingdom but not in the rest of the world was that it would result in more deaths from fatal adverse drug reactions (ADRs) than the number of IE deaths. The main aim of this study was to quantify and describe the ADRs with amoxicillin or clindamycin for IE AP. The second aim was to infer a crude incidence of anaphylaxis associated with amoxicillin for IE AP. Material and Methods The Medical Dictionary for Regulatory Activities (MedDRA) was used to group ADRs for IE AP using the broad Standardized MedDRA Queries “Anaphylactic reaction, Amoxicillin, Clindamycin, Clostrid…
Severe Clostridium difficile infection with extremely high leucocytosis complicated by a concomitant bloodstream infection caused by Klebsiella pneum…
2020
Highlights • Exposure to antibiotics after surgery increase risk of Cl. difficile infection. • Sudden high leucocytosis may be sign of poor outcome in Cl. difficile case. • Oral Vancomycin could be responsible for the growth of bloodstream Kl. pneumonia.
Thrombin generation is increased in patients with Clostridium difficile colitis – a pilot study
2019
Background: There are only limited data in the literature on the thrombotic risk of patients with Clostridium difficile (CD) colitis, although this disease is widespread throughout the world. Objective: The aim of this study was to explore thrombin generation in these patients - the best way to evaluate their coagulation. Methods: A prospective observational study was conducted during 15 months on hospitalized patients with CD colitis. Thrombin generation was performed in platelet-poor plasma using a Ceveron® alpha analyzer and was compared with a group of volunteer control subjects. Results: Thirty-three patients and 51 control subjects were enrolled in the study. Two biomarkers - mean vel…