Amount Of Esterase Research Articles

Variation of wine preference amongst consumers is influenced by the composition of salivary proteins

The preferences of consumers for different flavours and aromas in wine are varied and may be explained by inherent factors such as cultural background, wine education and personal taste of the wine consumer. Wine flavour, as perceived in the mouth, includes aroma compounds released through the retronasal pathway, which are shaped by interactions with saliva. Saliva and wine interactions could provide an explanation as to why wine tasters express different preferences for wine. To test this hypothesis, 13 Western and 13 Chinese experienced wine tasters were recruited. Sensory evaluation was performed in formal surroundings to acquire free description-based and perceived sensory intensity data using the Pivot® Profile and continuous scale assessment, respectively. Participants’ saliva samples were collected before the sensory evaluation and spiked into a wine sample to investigate the impact on the wine’s volatile release using comprehensive two-dimensional gas chromatography–mass spectrometry (GC × GC–MS). Saliva samples were subjected to enzyme activity assays and protein composition profiling by Tandem Mass Tag (TMT) quantitative proteomics. The wine tasters showed differences in wine flavour perception, which was supported by the difference in wine volatile release resulting from the addition of saliva. The two groups of participants did not have significant differences in total salivary protein concentrations or the amounts of esterase and α-amylase. However, statistically significant variations in the concentrations of specific proteins (proline-rich proteins (PRPs) and lipocalin-1 (LCN-1); p < 0.01) were found between the two groups. Significant correlations between perceived intensities of wine attributes and concentrations of PRPs and LCN-1 were observed. These results indicate that the composition of proteins in saliva is a factor that influences wine perception and preference. Our results provide a biochemical basis for understanding preference for food based on interactions between aroma compounds and salivary proteins and could be used to suggest foods or beverages to particular cultural groups.

GENDER SPECIFIC CHANGES IN MOUSE BLOOD ESTRERASE PROFILE AT THE ACUTE INTOXICATION BY 2-(О-CRESYL)-4Н-1,3,2-BENZODIOXAPHOSPHORIN-2-OXIDE

A comparative investigation of the esterase profiles of blood of mice of both genders exposed to various doses of 2-(o-crezyl)-4H-1,3,2-benzodioxaphosphorin-2-oxide (CBDP) was made an hour after its percutaneous injection to animals. A lesser amount of esterase in males blood made them more susceptible to CBDP action as compared to females. It was shown that CBDP equally inhibits the activity of carboxyl esterase and butyryl choline esterase in blood serum of both male and female mice. Statistically significant differences in inhibition degree of enzymes between males and females were found out and therefore it is not recommended to use mixed groups of animals when performing testing of serine esterase inhibitors.

Involvement of Nonbinding Site Proteinases in the Development of Resistance of &lt;I&gt;Helicoverpa armigera&lt;/I&gt; (Lepidoptera: Noctuidae) to Cry1Ac

Development of resistance to transgenic crops expressing the Cry toxin from Bacterium thuringiensis (Bt) has been the major concern for the long-term success of Bt crops. Alterations in nonbinding site proteinases and Bt toxin receptors are the two types of mechanisms responsible for Bt resistance in resistant insects. However, little is known about the relative contributions of the two types of mechanisms in the early and late phases of the development of Bt resistance. To address the relative contributions of four nonbinding site proteinases including esterase, total protease, chymotrypsin, and glutathione S-transferase in the early and late phases of the development of Cry1Ac resistance, we analyzed the relationships between nonbinding site proteinases and resistance of three groups of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) strains with different resistance levels because of different geographic origins and selection pressures. Positive correlation (esterase, glutathione-S-tranferases [GST], and chymotrypsin) and negative correlation (total midgut protease) were observed within the low to moderate group II resistant strains. Such correlations were less obvious within the low to moderate group III resistant strains because of only threefold differences in LC50 values. Relative to the unselected susceptible 96S strain, the two highly resistant group I resistant strains BtI and BtR have the same amounts of esterase, GST, and chymotrypsin and disproportionally decreased the amount of total midgut protease. Overall, the low to moderate resistant strains had the lowest amount of the nonbinding site proteinases. The results obtained suggest that alternations in the nonbinding site proteinases probably can only confer low to moderate levels of resistance and thus are enriched in the early phase of the development of Cry1Ac resistance.

Sex differences and androgenic regulation of esterases in the house mouse

The distribution of molecular forms of esterases in serum, liver and kidney from NMRI, C57BL/6 and A/J mice and the effect of testosterone propionate on the zymograms were investigated. It was found that the different tissues are specific in the pattern of esterases and that, especially in serum and kidney, the distribution of esterases is highly sex specific. Sex hormones are responsible for this. Administration of testosterone has an effect on the amounts of esterases in both sexes, primarily reducing the normal sex differences.

Enhanced degradation and toxicity reduction of dihexyl phthalate by Fusarium oxysporum f. sp. pisi cutinase

This research aims to investigate the efficiency of two lipolytic enzymes--fungal cutinase and yeast esterase--upon the biodegradation of dihexyl phthalate (DHP). During the enzymatic degradation of DHP dissolved in methanol, several degradation products were detected and their time-course changes were monitored using GC/MS. The DHP-degradation rate of cutinase was surprisingly high; i.e. almost 70% of the initial DHP (500 mg l(-1)) was decomposed within 4.5 h. Although the same amount of esterase was employed, more than 85% of the DHP remained after 3 days. Almost all the DHP was converted by cutinase into 1,3-isobenzofurandione (IBF), whereas hexyl methyl phthalate and IBF were abundantly produced by esterase. In addition, the toxicities of the DHP-degraded products by esterase were evaluated using various recombinant bioluminescent bacteria, which caused oxidative and protein damage, whereas the hydrolysis products from cutinase never caused any cellular damage in the methanol-containing reaction system. Cutinase starts to act as a DHP-degrader much earlier and faster than esterase, with high stability in ester-hydrolytic activity, therefore a plausible approach to the practical application of cutinase for DHP degradation in the DHP-contaminated environments may be possible. This study describes the enhanced degradation and detoxification of DHP using Fusarium oxysporum f. sp. pisi cutinase.

Genetic Variation Along Time in a Brazilian Population of Aedes Aegypti (Diptera: Culicidae), Detected by Changes in the Esterase Patterns

Aedes aegypti from the Brazilian cities of São José do Rio Preto (SJ) and Goiânia (GO) were analyzed as to their esterase patterns and the results were compared with data obtained about 5 years before for SJ population. Esterase bands not detected in the previous study were now observed in mosquitoes from both SJ and GO populations, being the last considered a population resistant to insecticides. Other similarities between SJ and GO populations in this study, and some differences in comparison with the previous data on SJ were observed, involving, in addition to changes in band type, changes in frequency of mosquitoes expressing them and differential gene activation during development. As it is generally true for genetic features, changes in the esterase patterns are expected to be the result of factors such as selection by environmental conditions and genetic drift. In the present case, continuous use of insecticides aiming mosquito population size control in SJ by sanitary authorities could be involved in the observed changes. Changed esterases were classified as carboxylesterases and cholinesterases, which are enzymes already shown to take part in the development of resistance in several organisms. In addition, data obtained in the elapsed time by authorities responsible for the mosquito control has shown increasing insecticide resistance of SJ population mosquitoes parallel to increase in the total amount of esterases, reinforcing the mentioned possibility.

The human macrophage response during differentiation and biodegradation on polycarbonate-based polyurethanes: Dependence on hard segment chemistry

Human monocytes, isolated from whole blood, were seeded onto tissue culture grade polystyrene (PS) and three polycarbonate-based polyurethanes (PCNUs) (synthesized with either 1,6-hexane diisocyanate (HDI) or 4,4′-methylene bis-phenyl diisocyanate (MDI), poly(1,6-hexyl 1,2-ethyl carbonate) diol (PCN) and 1,4-butanediol (BD) in different stoichiometric ratios (HDI:PCN:BD 4:3:1 or 3:2:1 and MDI:PCN:BD 3:2:1) (referred to as HDI431, HDI321 and MDI321, respectively). Following their differentiation to monocyte-derived macrophages (MDMs) the cells were trypsinized and reseeded onto each of the PCNUs synthesized with either 14C-HDI or 14C-BD and degradation was measured by radiolabel release (RR). When the differentiation surface was MDI321, there was more RR from 14C-HDI431 than from any other surface ( p < 0.0001 ) whereas the amount of esterase (identified by immunoblotting) as well as the esterase activity was the greatest in MDM differentiated on PS, reseeded on 14C-HDI431 ( p < 0.0001 ). The effect of potential degradation products (methylene dianiline (MDA) and BD) from the PCNUs was carried out to determine possible links between products and substrate-induced activation of MDM. MDA was found to inhibit RR 60% from MDM seeded on 14C-MDI321B ( p < 0.0001 ), ∼20% from 14C-HDI431 ( p = 0.002 ) and no effect from 14C-HDI321B. MDA inhibited esterase activity 30% from MDM only on 14C-MDI321B ( p = 0.003 ), but no effect on esterase activity was observed for the other two polymers. BD had no inhibitory effect on RR from any PCNU, but did inhibit esterase activity in MDM on 14C-HDI431 ( p = 0.025 ). This study indicates that the degradation of a specific material is a multi-factorial process, dictated by its susceptibility to hydrolysis, the effect of specific products generated during this course of action, and perhaps not as well appreciated, the material's inherent ability to influence enzyme synthesis and release.

Relationship between amount of esterase and gene copy number in insecticide-resistant Myzus persicae (Sulzer)

Relationship between amount of esterase and gene copy number in insecticide-resistant Myzus persicae (Sulzer)

Relationship between amount of esterase and gene copy number in insecticide-resistant Myzus persicae (Sulzer)

Overproduction of the insecticide-degrading esterases, E4 and FE4, in peach-potato aphids, Myzus persicae (Sulzer), depends on both gene amplification and transcriptional control, the latter being associated with changes in DNA methylation. The structure and function of the aphid esterase genes have been studied but the determination of their copy number has proved difficult, a common problem with gene amplification. We have now used a combination of pulsed-field gel electrophoresis and quantitative competitive PCR to determine relative esterase gene copy numbers in aphid clones with different levels of insecticide resistance (R1, R2 and R3). There are approx. 4-fold increases between susceptible, R1, R2 and R3 aphids, reaching a maximum of approx. 80 times more genes in R3; this gives proportionate increases in esterase protein relative to susceptible aphids. Thus there is no overexpression of the amplified genes, in contrast with what was thought previously. For E4 genes, the loss of 5-methylcytosine is correlated with a loss of expression, greatly decreasing the amount of enzyme relative to the copy number.

Comparison of microplate esterase assays and immunoassay for identifying insecticide resistant variants of Myzus persicae (Homoptera: Aphididae)

AbstractInsecticide resistant Myzus persicae (Sulzer) employ increased esterase activity to detoxify insecticides by hydrolysis and sequestration. The amount of esterase, and hence resistance, in individual aphids can be determined by measuring either overall naphthyl acetate hydrolysis in crude homogenates, or the specific enzyme responsible (E4 or FE4) after electrophoresis or immunological isolation. The ability of a total esterase assay, done in microplates, to discriminate between susceptible (S) aphids and resistant variants (R1, R2) with different amounts of E4/FE4, was compared with the resolving power of the more elaborate immunoassay technique. The immunoassay gave the better discrimination between variants, resolving them all with greater than 95% confidence, with particularly good separation of R1, from S. The microplate assay using crude homogenates, although a poorer discriminator, identified most of the very resistant (R2) aphids, and provided a robust and widely accessible method for broadly representing the resistance of field populations.

Enantioselective hydrolysis of oxazepam 3‐acetate by esterases in human and rat liver microsomes and rat brain s9 fraction

Rates of hydrolysis of racemic and enantiomeric oxazepam 3-acetates (OXA) by esterases in human and rat liver microsomes and rat brain S9 fraction were compared. When rac-OXA was the substrate, esterases in human and rat liver microsomes were highly enantioselective toward (R)-OXA. In contrast, esterases in rat brain S9 fraction were highly enantioselective toward (S)-OXA. Hydrolysis rates of rac-OXA were highly dependent on the amount of esterases used. At 0.05 mg protein equivalent of esterases and 150 nmol of rac-OXA per ml of incubation mixture, the (R)-OXA was hydrolyzed 3.6-fold and 18.5-fold faster than (S)-OXA by rat and human liver microsomes, respectively. The specific activities (nmol of OXA hydrolyzed/mg microsomal protein/min) of liver microsomes in the hydrolysis of enantiomerically pure (R)-OXA were approximately 120 (rat) and 1,980 (human), and in the hydrolysis of enantiomerically pure (S)-OXA were 4 (rat) and 7 (human), respectively. In the incubation of rac-OXA with rat brain S9 fraction, (S)-OXA was hydrolyzed approximately 6-fold faster than (R)-OXA. Results also indicated an enantiomeric interaction in the hydrolysis of rac-OXA by esterases in rat and human liver microsomes; the presence of (R)-OXA stimulated the hydrolysis of (S)-OXA, whereas the presence of (S)-OXA inhibited the hydrolysis of (R)-OXA. In rat brain S9 fraction, the presence of (R)-OXA inhibited the hydrolysis of (S)-OXA, whereas the presence of (S)-OXA appeared to have stimulated the hydrolysis of (R)-OXA.

Preparation of oxygen-18-labeled lipoxygenase metabolites of arachidonic acid.

Plasma pseudocholinesterase and porcine liver esterase were used to catalyse the incorporation of the stable isotope oxygen-18 into the carboxyl moiety of lipoxygenase metabolites of arachidonic acid. This simple method produces eicosanoid products containing two oxygen-18 atoms; but the enzymes studied were found to display large substrate specificity in the efficiencies at which oxygen-18 could be incorporated into the lipoxygenase metabolites. Furthermore, [18O2]LTB4 was found not to back exchange during in vitro incubation with human neutrophils. The methods involved for stable isotope incorporation are simple, efficient and produce highly enriched species in a short time. By varying the type of esterase, the amount of esterase or the length of incubation highly enriched species of all eicosanoids tested could be prepared.

STUDIES ON YEAST ESTERASE

An esterase (carboxylic acid hydrolase EC 3 1.1.1.) has been prepared from Saccharomyces cerevisiae. This esterase is active at pH 4.4 and, though it is unstable in solution, it can be maintained in an active form either by lyophilization or by coupling to an affinity gel. At pH 4.4, yeast esterase can hydrolyse between 20 and 40% of the esters commonly present in beer, and it is capable of synthesizing ethyl acetate from ethanol and acetic acid in a simple buffered solution without the provision of a co-factor. Different yeast strains yield different amounts of esterase, and there appears to be a positive correlation between the ability of the yeast to form esterase and the level of esters present in fermentations accomplished by that yeast.

Use of Starch-Gel Electrophoresis to Illustrate Inhibition of Tissue Esterases by Organophosphorus Pesticides. II. Comparison of Homogenates of Different Origin

Abstract Comparison of starch-gel electrophoresis patterns of ali-esterases of rabbit spleen, lung, brain, heart, and kidney showed that liver contained the most esterase, kidney the next greatest amount; patterns were generally similar, although amounts of esterase differed in different parts of the gel. Similar studies on various species of mammals, fowl, and fish showed that, in general, patterns of the same organ differed among species. Various enzymes appeared to be somewhat specific with respect to inhibitors but not to substrates, under the conditions used. Bromine treatment increased the inhibitory effect of Schradan, Dibrom and Ruelene, and EPN and parathion, in decreasing order.

The Ester=Splitting Protecties of the Peripheral Nerves.

The results of this experiment may be briefly summarized as follows: 1. Filtered, glycerin-water extracts of the peripheral nerves, when tested with tributyrin, have an ester-splitting capability, which is capable of splitting up tributyrin into glycerin and butyric acid, and this power of the peripheral nerves is destroyed by heating the emulsion for five minutes in a water bath. 2. The increase in acidity, when expressed in n/20-NaOH is reasonably uniform in a unit weight of the nerve tissues in a unit length of time, and the amount of esterase does not appear to vary considerably in normal animals examined in these experiments. 3. After splitting for two hours the mean value of the five percent suspension, extracted in 50 per cent glycerin-water, will be 0.42 or thereabout. 4. Fresh human nerves as well as those obtained from fresh autopsy materials, as far as these experiments are concerned, seem to have markedly less lipolytic activity as compared with those of animals; but without an extended series of observations it is impossible to draw definite conclusions concerning this point.

THE EFFECT OF FEEDING SUGAR UPON THE ESTERASE CONTENT OF THE BLOOD SERUM AND ORGANS IN PHOSPHORUS POISONING

1. Clear, filtered glycerol extracts of chopped liver, spleen, and kidney contain an ester-splitting ferment. 2. The esterase content of extracts of the liver and spleen of normal dogs is reasonably constant. 3. The amount of esterase in the liver does not appear to vary to any great extent from the normal, in poisoning with chloroform and phosphorus. 4. Feeding large quantities of sugar and increasing the amount of glycogen in the liver is accompanied by a marked increase in the esterase content of that organ. This increase is also evident in phosphorus-poisoned animals which have been fed large amounts of sugar. 5. The feeding of sugar does not prevent the increase in esterase in the blood serum of animals poisoned with phosphorus. 6. The esterolytic power of extracts of the kidney varies considerably in different dogs.