Search results for "carbohydrates"
showing 10 items of 474 documents
A search for beta-lactamase in chlamydiae, mycoplasmas, planctomycetes, and cyanelles: bacteria and bacterial descendants at different phylogenetic p…
2000
Bacteria from different phylogenetic positions such as chlamydiae, mycoplasmas, planctomycetes and also endosymbiotic murein-containing cyanelles were investigated for the production of beta-lactamases. No beta-lactamase activity was found in bacteria lacking murein such as Chlamydia pneumoniae, Mycoplasma pneumoniae, Pirellula marina and Planctomyces maris. In the murein-containing cyanelles of Cyanophora paradoxa no beta-lactamase activity could be detected.
The Non-Amyloidogenic Pathway: Structure and Function of α-Secretases
2006
The amyloid cascade hypothesis is the most accepted explanation for the pathogenesis of Alzheimer’s disease (AD). APP is the precursor of the amyloid β peptide (Aβ), the principal proteinaceous component of amyloid plaques in brains of Alzheimer’s disease patients. Proteolytic cleavage of APP by the α-secretase within the Aβ sequence precludes formation of amyloidogenic peptides and leads to a release of soluble APPsα which has neuroprotective properties. In several studies, a decreased amount of APPsα in the cerebrospinal fluid of AD patients has been observed. Three members of the ADAM family (a disintegrin and metalloproteinase) ADAM-10, ADAM-17 (TACE) and ADAM-9 have been proposed as α-…
Kinetics of citrate uptake in growing cells ofLeuconostocspp.
1996
Citrate uptake was studied in growing cells of Leuconostoc mesenteroides subsp. mesenteroides. A Michaelis-Menten pattern with the dianionic form of citrate as the limiting substrate has been proposed. It was validated for different fermentations varying the initial citrate concentrations and the pH medium. This latter did not modify the rate of the process which was clearly confirmed using experiments with resting cells. The model was used to compare the kinetics of citrate consumption between several strains of Leuconostoc mesenteroides subsp. mesenteroides, Leuconostoc mesenteroides subsp. cremoris and Leuconostoc lactis.
Isolation and characterization of yeast monomorphic mutants of Candida albicans.
1994
A method was devised for the isolation of yeast monomorphic (LEV) mutants of Candida albicans. By this procedure, about 20 stable yeast-like mutants were isolated after mutagenesis with ethyl methane sulfonate. The growth rate of the mutants in different carbon sources, both fermentable and not, was indistinguishable from that of the parental strain, but they were unable to grow as mycelial forms after application of any of the common effective inducers, i.e., heat shock, pH alterations, proline addition, or use of GlcNAc as the carbon source. Studies performed with one selected strain demonstrated that it had severe alterations in the chemical composition of the cell wall, mainly in the le…
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…
Chemoselektive Fluoreszenzstudien am Subtilisin und “Thiosubtilisin”
1985
Chemoselective Fluorescence Studies with Subtilisin and “Thiosubtilisin” The serine hydroxy group in the active site of subtilisin is selectively “phosphylated”3). This is demonstrated using the fluorescent phosphinic fluoride 1. “Thiosubtilisin” does not react with 1 but with the SH-selective and fluorescent vinyl sulfone 2.
Lack of association betweenMDM2promoter SNP309 and clinical outcome in patients with neuroblastoma
2014
While a polymorphism located within the promoter region of the MDM2 proto-oncogene, SNP309 (T > G), has previously been associated with increased risk and aggressiveness of neuroblastoma and other tumor entities, a protective effect has also been reported in certain other cancers. In this study, we evaluated the association of MDM2 SNP309 with outcome in 496 patients with neuroblastoma and its effect on MDM2 expression. No significant difference in overall or event-free survival was observed among patients with neuroblastoma with or without MDM2 SNP309. The presence of SNP309 does not affect MDM2 expression in neuroblastoma. Pediatr Blood Cancer 2014; 61:1867–1870. © 2014 Wiley Periodicals,…
Organometallic complexes with biological molecules: XIII. Organotin(IV)[meso-tetra (4-carboxyphenyl)porphinate]s and the cell cycle: a flow-cytometri…
1999
The cytotoxic derivatives diorganotin(IV) and triorganotin(IV) [meso-tetra(4-carboxyphenyl)porphinates, with stoichiometries [R2Sn]2TPPC and [R3Sn]4TPPC [R = Me, Bu, Ph; TPPC4−= meso-tetra(4-carboxyphenyl)porphinate4−], namely bis[dimethyltin(IV)], bis[dibutyltin(IV)], bis[diphenyltin(IV)], tetra[trimethyltin(IV)], tetra[tributyltin(IV)] and tetra[triphenyltin(IV)] [meso-tetra(4-carboxyphenyl)porphinate]s, have been used to investigate their effects on the cultured human kidney cell cycle in order to understand further the origin of cell-growth inhibition induced by the above-mentioned chemicals. The cell-cycle-dependent DNA content distribution of cultured cells exposed to these compounds…
N-glycosylation efficiency is determined by the distance to the C-terminus and the amino acid preceding an Asn-Ser-Thr sequon
2011
N-glycosylation is the most common and versatile protein modification. In eukaryotic cells, this modification is catalyzed cotranslationally by the enzyme oligosaccharyltransferase, which targets the β-amide of the asparagine in an Asn-Xaa-Ser/Thr consensus sequon (where Xaa is any amino acid but proline) in nascent proteins as they enter the endoplasmic reticulum. Because modification of the glycosylation acceptor site on membrane proteins occurs in a compartment-specific manner, the presence of glycosylation is used to indicate membrane protein topology. Moreover, glycosylation sites can be added to gain topological information. In this study, we explored the determinants of N-glycosylati…
Possible Roles of Mannoproteins in the Construction of Candida Albicans Cell Wall
1993
The shape of Candida albicans cells depends on their cell walls and some of their mannoproteins may act as modulators of the final molecular architecture. If that were the case, the wall mannoproteins might form part of what could be called a “morphogenetic code”.