Faecal leukocyte esterase activity is an alternative biomarker in inflammatory bowel disease

Background: Leukocyte cytosolic proteins (e.g., calprotectin) are emerging biomarkers for inflammatory bowel disease. Leukocyte aryl esterase activity has been commonly used for sensitive detection of leukocytes in human body fluids such as urine. Urine test strip results are generally reported in categories. As automated strip readers allow quantitative data to be reported, sensitive quantitative detection of leukocytes in body fluids has become possible. Here, we explored the use of leukocyte esterase as a potential alternative faecal biomarker for inflammatory bowel disease. Methods: We evaluated leukocyte esterase activity in faecal extracts and compared Cobas u 411 (Roche) quantitative reflectance data with calprotectin concentration for 107 routine samples. Stability of leukocyte esterase for trypsin digestion was carried out by adding trypsin to the extract. Incubation occurred at 37 ° C for 24 h or 48 h. Results: Reproducibility of the reflectance signal was good (within-run imprecision: 6.1%; between-run imprecision: 6.2%). Results were linear in the range 10 3 – 10 6 WBC/100 mg faeces. The lower limit of detection was 4 WBC/ μ L and the lower limit of quantification was 5 WBC/ μ L. Stability of LE activity in stool and faecal matrix was good. An adequate correlation was obtained between leukocyte esterase activity and the faecal calprotectin concentration: log(y)  =  4.28 + 0.29log(x). In vitro experiments monitored the digestion of leukocyte esterase and faecal calprotectin. Leukocyte esterase activity was significantly less affected by trypsin activity than calprotectin immunoreactivity. Conclusions: Quantitative leukocyte esterase activity of faecal extracts provides information about the leukocyte count in the gut lumen. Leukocyte esterase is a promising and affordable alternative biomarker for monitoring inflammatory bowel disease

Effect of lithium on acetylcholine esterase activity, and isozyme pattern in developing chick brain

Acetylcholine Esterase is an enzyme, which hydrolyses acetylcholine and is used as a marker for cholinergic neural function. It is known to be involved in synaptogenesis. While on one hand it is known to be a marker for the developing chick brain it is also implicated in neurodegenerative diseases. In vertebrates the protein is synthesized by a single gene and undergoes alternative splicing to give 6-8 isoforms. Isozyme patterns of acetylcholine esterase have been suggested to be useful prognostic markers of neuronal degeneration. Lithium a well-known teratogen is known to induce apoptosis in the developing chick brain. Understanding the dynamics of acetylcholine esterase isoform pattern in lithium induced neural tissue damage would help elucidating the role of these isoforms in frank neurodegenerative diseases. We have therefore studied activity and isozyme pattern of acetylcholine esterase in lithium treated and control 7 day old developing chick brain and report the same

Studies on the non-specific esterases of Saccharomyces cerevisiae : a thesis in partial fulfillment [sic.] of the requirements for the degree of Master of Science in Microbiology at Massey University

Twenty wine-making and three laboratory strains of Saccharomyces cerevisiae were examined for non-specific esterases by Polyacrylamide Gel Electrophoresis. All wine-making strains contained the fast alleles of the Est 1 and Est 2 loci, confirming there is a selective advantage for the Est 1f and Est 2f genes in these strains. Only one wine-making strain carried the Est 3 and Est 4 genes, which was a much lower frequency than that published. The three laboratory strains all contained the Est 1f and Est 2s genes. A new non-specific esterase band, labelled Est 5, was identified by using a modified staining technique, which was apparently of low molecular weight as it travelled with the tracking dye front. Fast and slow alleles of Est 1 and Est 2 were determined to be charge allozymes. Est 2 proteins were considered to be polymeric, probably dimeric, and the Est 1 proteins to undergo post-translational modification. Difficulty in resolving the Est 4 band was overcome by adding Triton X-100 to cell suspensions before disruption, indicating this esterase protein may be particulate bound. Molecular weights were determined by Ferguson Plots to be 51,000 ± 10,000 daltons (Est 2), 60.000 ± 12,000 daltons (Est 3), 73,000 ± 15,000 daltons (Est l), and 113,000 ± 23,000 daltons (Est 4). No isolates of S. cerevisiae for comparison of allele frequencies could be made from mature locally-grown grapes, indicating that this species is rare in the New Zealand environment, which is in accordance with published studies. No "inducible" non-specific esterases were found in strains examined at different stages in the life cycle, or by growth in different media. The level of esterase activity in cells increased throughout aerobic growth in liquid media, but was quickly lost during fermentation. Esterase activity during sporulation also decreased. A non-specific esterase mutant was induced by ethyl methane-sulfonate and detected by the hydrolysis of α-naphthyl acetate incorporated into solid medium. This mutant lost expression of both Est If and Est 2s , as did subsequent mutants produced by hybridisation. Segregation of esterase-deficient to esterase-proficient spores after hybridisation, showed that two unlinked loci were involved in esterase suppression, both genes being unlinked to ade 1, Est 1 and mating type locus MAT. It is hypothesised these genes are a suppressor (SUP) and a mutated regulator (Reg Est− ). Gas Liquid Chromatography was used to quantitatively determine volatile ester concentrations produced during fermentation. Selected wine-making strains and diploid strains produced by micromanipulation and having different non-specific esterase compositions were fermented to the limit of their ethanol tolerance in Reisling Sylvaner grape juice and Complete Defined Medium. Ethyl acetate, ethyl propanoate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, ethyl dodecanoate, 2-phenethyl acetate, n-hexyl acetate and iso-pentyl acetate were all quantitated. A maximum error of ±30% was determined for differences in ester concentration between two fermentations using the same strain. Correction for differences in fermentation ability by different strains was attempted, and the resulting ester concentrations compared qualitatively. Results indicate that differences in volatile ester concentrations between strains are not due to the esterase composition. The non-specific esterases probably have little if any influence on wine bouquet as the majority of ester production is late in fermentation when esterase activity has ceased

Inhibition of pancreatic cholesterol esterase reduces cholesterol absorption in the hamster

BACKGROUND: Pancreatic cholesterol esterase has three proposed functions in the intestine: 1) to control the bioavailability of cholesterol from dietary cholesterol esters; 2) to contribute to incorporation of cholesterol into mixed micelles; and 3) to aid in transport of free cholesterol to the enterocyte. Inhibitors of cholesterol esterase are anticipated to limit the absorption of dietary cholesterol. RESULTS: The selective and potent cholesterol esterase inhibitor 6-chloro-3-(1-ethyl-2-cyclohexyl)-2-pyrone (figure 1, structure 1) was administered to hamsters fed a high cholesterol diet supplemented with radiolabeled cholesterol ester. Hamsters were gavage fed (3)H-labeled cholesteryl oleate along with inhibitor 1, 0–200 micromoles. Twenty-four hours later, hepatic and serum radioactive cholesterol levels were determined. The ED(50 )of inhibitor 1 for prevention of the uptake of labeled cholesterol derived from hydrolysis of labeled cholesteryl oleate was 100 micromoles. The toxicity of inhibitor 1 was investigated in a 30 day feeding trial. Inhibitor 1, 100 micromoles or 200 micromoles per day, was added to chow supplemented with 1% cholesterol and 0.5% cholic acid. Clinical chemistry urinalysis and tissue histopathology were obtained. No toxicity differences were noted between control and inhibitor supplemented groups. CONCLUSIONS: Inhibitors of cholesterol esterase may be useful therapeutics for limiting cholesterol absorption

Design of surface-active artificial enzyme particles to stabilize Pickering emulsions for high-performance biphasic biocatalysis

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Surface-active artificial enzymes (SAEs) are designed and constructed by a general and novel strategy. These SAEs can simultaneously stabilize Pickering emulsions and catalyze biphasic biotransformation with superior enzymatic stability and good re-usability; for example, for the interfacial conversion of hydrophobic p-nitrophenyl butyrate into yellow water-soluble p-nitrophenolate catalyzed by esterase-mimic SAE

An Open Receptor-Binding Cavity of Hemagglutinin-Esterase-Fusion Glycoprotein from Newly-Identified Influenza D Virus: Basis for Its Broad Cell Tropism.

Influenza viruses cause seasonal flu each year and pandemics or epidemic sporadically, posing a major threat to public health. Recently, a new influenza D virus (IDV) was isolated from pigs and cattle. Here, we reveal that the IDV utilizes 9-O-acetylated sialic acids as its receptor for virus entry. Then, we determined the crystal structures of hemagglutinin-esterase-fusion glycoprotein (HEF) of IDV both in its free form and in complex with the receptor and enzymatic substrate analogs. The IDV HEF shows an extremely similar structural fold as the human-infecting influenza C virus (ICV) HEF. However, IDV HEF has an open receptor-binding cavity to accommodate diverse extended glycan moieties. This structural difference provides an explanation for the phenomenon that the IDV has a broad cell tropism. As IDV HEF is structurally and functionally similar to ICV HEF, our findings highlight the potential threat of the virus to public health

The Aspergillus niger faeB gene encodes a second feruloyl esterase involved in pectin and xylan degradation and is specifically induced in the presence of aromatic compounds

The faeB gene encoding a second feruloyl esterase from Aspergillus niger has been cloned and characterized. It consists of an open reading frame of 1644 bp containing one intron. The gene encodes a protein of 521 amino acids that has sequence similarity to that of an Aspergillus oryzae tannase. However, the encoded enzyme, feruloyl esterase B (FAEB), does not have tannase activity. Comparison of the physical characteristics and substrate specificity of FAEB with those of a cinnamoyl esterase from A. niger [Kroon, Faulds and Williamson (1996) Biotechnol. Appl. Biochem. 23, 255-262] suggests that they are in fact the same enzyme. The expression of faeB is specifically induced in the presence of certain aromatic compounds, but not in the presence of other constituents present in plant-cell-wall polysaccharides such as arabinoxylan or pectin. The expression profile of faeB in the presence of aromatic compounds was compared with the expression of A. niger faeA, encoding feruloyl esterase A (FAEA), and A. niger bphA, the gene encoding a benzoate-p-hydroxylase. All three genes have different subsets of aromatic compounds that induce their expression, indicating the presence of different transcription activating systems in A. niger that respond to aromatic compounds. Comparison of the activity of FAEA and FAEB on sugar-beet pectin and wheat arabinoxylan demonstrated that they are both involved in the degradation of both polysaccharides, but have opposite preferences for these substrates. FAEA is more active than FAEB towards wheat arabinoxylan, whereas FAEB is more active than FAEA towards sugar-beet pectin