Search results for "carbohydrates"
showing 10 items of 474 documents
Enzymatic glycosylation of o-glycopeptides
1992
Abstract O-Glycosylation of serine derivatives carried out with N-urethane protected glucosamine yields O-glycopeptides which are regio- and stereoselectively galactosylated with the aid of β-1,4-galactosyltransferase (EC 2.4.1.22).
Synthesis and Assembly of Wall Polymers on Regenerating Yeast Protoplasts
1983
Accumulation of chitin and glucan on S. cerevisiae and C. albicans protoplasts begins shortly after resuspension in the regeneration medium, and mannoprotein molecules also appear retained by the regenerating wall after 30–60 minutes in S. cerevisiae or after a longer lag period in C. albicans. Nevertheless, a considerable fraction of the synthesized mannoproteins, which in SDS-acrylamide gels exhibit a different pattern from that of wall mannoproteins of cells, are still released to the growth medium during at least eight hours. De novo synthesis of chitin synthase, but not of glucan synthase, is observed in S. cerevisiae from about 30 minutes after initiation of the regeneration process. …
Engraulis encrasicolus larvae from two different environmental spawning areas of the Central Mediterranean Sea: first data on amino acid profiles and…
2020
Early life stages of marine fish populations may be strongly affected by environmental factors. Changes in the physical environment or the availability of food resources could lead to stress-related physiological responses affecting larval fitness, growth and survival. In the present study, we determined, for the first time, amino acid composition (AAC), lipid, and carbohydrate content, as well as alkaline phosphatase and peroxidase activities in larvae from the European anchovy Engraulis encrasicolus. Fishes were caught in two different spawning areas of the Strait of Sicily, characterized by different environmental conditions, including a coastal upwelling with a lower temperature (Advent…
The chemistry of death--Adipocere degradation in modern graveyards.
2015
The formation of adipocere slows further decomposition and preserves corpses for decades or even centuries. This resistance to degradation is a serious problem, especially with regard to the reuse of graves after regular resting times. We present results from an exhumation series in modern graveyards where coffins from water-saturated earth graves contained adipocere embedded in black humic material after resting times of about 30 years. Based on the assumption that this humic material resulted from in situ degradation of adipocere, its presence contradicts the commonly held opinion that adipocere decomposition only occurs under aerobic conditions. To test our hypothesis, we collected black…
Chitin: A Structural Biopolysaccharide
2009
Chitin is a naturally occurring fibre-forming polymer that plays a protective role in many lower eukaryotes similar to that of cellulose in plants. Chemically it is a long-chain unbranched polysaccharide made of N-acetylglucosamine residues; it is the second most abundant organic compound in nature, after cellulose. Taking into account the structural role played by chitin, its metabolism (synthesis and degradation) is essential for different morphogenetic events. Absent in vertebrates and plants, chitin represents a parasite-specific target for chemotherapeutic attack and also plays a role in host immune responses. Because of its abundance in nature and its properties, biotechnological appl…
Synthetic Tumor-Associated Glycopeptide Antigens from the Tandem Repeat Sequence of the Epithelial Mucin MUC4
2004
In cancer research, the development of vaccines against tumor-associated antigens is of particular interest. Epithelial cells express mucin type glycoproteins, which are extensively O-glycosylated. In case of cancer, the expression of these mucins is increased, and their carbohydrate side chains show an aberrant glycosylation pattern. A set of single and double glycosylated hexadecapeptides representing the tandem repeat sequence of the epithelial mucin MUC4 carrying different tumor-associated carbohydrate antigens was prepared by sequential solid-phase glycopeptide synthesis. The crucial glycosyl amino acid building blocks containing the T N , T, sialyl-T N and (2,6)-sialyl-T antigens were…
Does catalase play a role in Adriamycin induced cardiotoxicity?
1980
Summary Adriamycin causes an increase of lipid peroxidation in mouse cardiac homogenates that is dependent on the concentration of the antiblastic. The same phenomenon is not observed in the hearts of mice treated with an elevated dose of Adriamycin in which, conversely, an increase of the antioxidizing enzyme catalase was noticed. The significance of these findings is discussed with relationship to the hypothesis of an enhanced free radicals formation at the basis of Adriamycin induced cardiotoxicity.
Behavior of carbohydrate-based material in black liquor during heating
2004
One industrial softwood Kraft black liquor was heat-treated (at 175 ?C and 190 ?C for 15-60 min) together with laboratory-made soda-AQ (wheat straw and reed canary grass) and Kraft (reed canary grass) black liquors (at 190 ?C for 30 min). The feedstock black liquors were characterized with respect to their polysaccharide (mainly xylem) and aliphatic carboxylic acid contents before and after the heat treatments. It was noted that, due to the higher amount of polysaccharides in the non-wood black liquors (8.2-16.6% of d.s) compared to that in the softwood black liquor (1.4% of d.s), the heat treatment in the former case resulted in a 5-30% increase in the amount of aliphatic acids formed by v…
Capillary column gas chromatographic identification of sugars in honey as trimethylsilyl derivatives.
1987
A method for identifying carbohydrates (mono-, di- and trisaccharides) in honey is presented. It is based on the separate preparation of both trimethylsilyl ethers and oxime trimethylsilyl ethers of the sugars followed by their gas chromatographic separation on a fused-silica capillary column coated with OV-101 using temperature programming. From the two chromatograms, the number of peaks given by each derivatized sugar, their relative retention times and peak-area ratios are used for identification. The identities of two unidentified trisaccharide peaks are considered. Quantitative applications to honey sugar analysis are discussed.
Synthetic Glycopeptides of the Tandem Repeat Sequence of the Epithelial Mucin MUC4 with Tumour-associated Carbohydrate Antigens
2004
Glycohexadecapeptides representing the tandem repeat sequence of the epithelial mucin MUC4 were prepared by applying a solid-phase methodology. The required glycosyl amino acid building blocks containing the tumour-associated saccharide antigens T N -, T,- sialyl-T N , (2,6)- and (2,3)-sialyl-T were synthesized according to a straightforward biomimetic strategy by stepwise extension of the saccharide side chain of a Fmoc-protected galactosamine threonine tert-butyl ester.