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PubMed1990

Isoelectric focusing in immobilized pH gradients of phosphoglucomutase and esterases from the spiny lobster.

A method is described for detecting polymorphisms of cephalothorax and tail homogenates of 25 puerulus staged Panulirus argus in phosphoglucomutase (PGM) and esterases. Isoelectric focusing in immobilized pH gradients was used. In the pH 6.0-8.0 interval for phosphoglucomutase and in the pH 3.5-5.0 and 4.2-4.9 ranges for esterases, both enzymes appeared as polymorphic band patterns. These could be explained by one locus with 2 alleles for phosphoglucomutase and 3 loci with 2, 3 and 4 alleles for esterases. Esterases exhibit a more extensive polymorphism in immobilized pH gradients than in polyacrylamide gel electrophoresis.

Alleles↗
PubMed1990

Effects of in ovo injection of carbamates on chick embryo hatchability, esterase enzyme activity and locomotion of chicks.

Carbaryl and aldicarb, two carbamate pesticides used extensively throughout the United States, are known to act as acetylcholinesterase inhibitors. We have demonstrated previously that exposure to carbaryl and aldicarb in young chicks caused persistent locomotion alterations with no correlation to esterase inhibition. In this study, we investigated the effects of these carbamates when injected in ovo to chick embryos, at two time periods (days 5 and 15) during incubation. Carbaryl dosed at 45 mg kg-1 egg weight was extremely toxic to the embryos on day 5 of incubation. Hatchability was reduced to 0% as compared to 80% when carbaryl was injected on day 15 of incubation. Aldicarb at 1.5 mg kg-1 egg weight had no major effect on hatchability when injected either on day 5 or day 15 of incubation (hatchability = 90 and 100%, respectively). Plasma, liver and brain esterases were measured in the chick at different time points during incubation and after hatching. Brain acetylcholinesterase (AChE) and liver cholinesterase (ChE) were inhibited significantly during incubation in embryos dosed on day 15 with both carbaryl and aldicarb. Liver carboxylesterase was inhibited significantly during incubation with only the carbaryl treatment. All esterase enzyme activities returned to normal after hatching. Plasma ChE and carboxylesterase levels were not affected with either carbaryl or aldicarb treatment from 8 until 47 days after hatching. Neither carbamate had any effect on brain neuropathy target esterase (NTE) activity either during incubation or after hatching. The locomotion of chicks was affected in both treatment groups until 47 days after hatching. This study indicates that carbaryl and aldicarb may cause long-term delayed alterations in the chicks.

Acetylcholinesterase↗
PubMed2007

Esterase-mediated bifenthrin resistance in a multiresistant strain of the two-spotted spider mite, Tetranychus urticae.

A field-collected multiresistant strain of Tetranychus urticae Koch exhibiting high resistance to bifenthrin was investigated in comparison with a susceptible laboratory strain. The esterase inhibitor S,S,S-tributyl-phosphorotrithioate (DEF) was able strongly to synergise bifenthrin toxicity in the resistant strain. Optimal conditions for determining esterase activities in T. urticae were determined, and a higher esterase activity towards several artificial substrates was found in this resistant strain, which had a preference for hydrolysing 4-nitrophenyl butyrate. Bifenthrin was able to bind the active centres of T. urticae esterases in vitro, as was determined after competition experiments by a Dixon plot, revealing a higher affinity of bifenthrin in the resistant strain. Bifenthrin-hydrolysing activity in the resistant and susceptible strains was examined in vitro and quantified with gas chromatography. A 7.2-fold higher metabolising rate was found in the resistant strain.

Animals↗
PubMed1997

Serum "B" esterases as a nondestructive biomarker for monitoring the exposure of reptiles to organophosphorus insecticides.

A field study was conducted to validate serum B esterases as nondestructive biomarkers (NDBs) in lizards. Serum butyrylcholinesterase (BChE) and carboxylesterase (CbE) activities were measured in lizards and four species of birds collected in an area of 0.5 ha sprayed with 0.36 kg a.i./ha of Folidol SE5 (5% parathion). Serum B esterase activities were determined in a total of 213 lizards (Gallotia galloti) and 81 birds of four species (Sylvia melanocephala, Serinus canaria, Parus caeruleus, and Erithacus rubecula) collected for 23 days after the spraying. A control group of 39 lizards and 58 birds was sampled before the spraying. No relationship was found between serum B esterases and sex or biometric parameters in all species. Inhibition of BChE (> 40%) and CbE (> 50%) activities was recorded in lizards 23 days after spraying. BChE activity was found to be more sensitive than CbE to inhibition by parathion. Inhibition of serum B esterase activities was recorded in only two bird species (S. melanocephala and S. canaria), but the number of individuals collected was much less than the lizards. The advantages and disadvantages of G. galloti as bioindicator of exposure to organophosphorus insecticides in the Canary Islands (Spain) are discussed in relation to birds commonly used for this purpose.

Animals↗
PubMed1998

Inhibition of esterases in the marine gastropod Littorina littorea exposed to cadmium.

Electrophoretic analysis of Littorina littorea esterases indicated the presence of a cathodal migration isoenzyme (EST-C), which was identified in extracts obtained from the gonad-digestive gland complex. A loss of EST-C enzyme activity was observed in individuals exposed to Cd2+. This loss of activity was complete in 86% of individuals dead by the action of Cd2+ and in 68% of those individuals that survived Cd2+ exposure. This difference was statistically significant. In vitro inhibition of esterases by different concentrations of Cd2+ and Cu2+ was studied in individuals not experimentally exposed to heavy metals, to determine whether EST-C inhibition was caused by direct binding of Cd2+ to the esterase molecule or by Cd2+ displacement of a metal ion from essential Cu2+- or Zn2+-containing proteins, which may then be responsible for the inhibition of esterase. Contrary to what happened when individuals were exposed to Cd2+, in the in vitro experiment with Cd2+, inhibition of anodal but not cathodal systems was observed. At the same time, when Cu2+ was used in the in vitro experiment, both anodal and cathodal systems were inhibited. These results suggest that the inhibition of EST-C activity by Cd2+ takes place in vivo and seems not to be due to the direct action of Cd2+ on the molecule, but rather is a process in which transcriptional, posttranscriptional, and other inhibitory processes may be involved.

Animals↗
PubMed1997

Resistance to insecticides in insect vectors of disease: est alpha 3, a novel amplified esterase associated with amplified est beta 1 from insecticide resistant strains of the mosquito Culex quinquesfasciatus.

Vector control programmes in many countries face the dual problems of parasite drug resistance and insecticide resistance in the insect vectors of the disease. Here we report for the first time a new esterase-based insecticide resistance mechanism in the filariasis vector Culex quinquefasciatus. The field collected COL strain of C. quinquefasciatus from Columbia was heterogeneous for organophosphorus insecticide resistance. On native polyacrylamide gels it had an elevated beta-naphthyl acetate specific esterase with the same Rf as that for the Est beta 1s involved in insecticide resistance in other strains of this mosquito species. After five generations of temephos insecticide selection, both the esterase specific activity with p-nitrophenyl acetate and the temephos LC50 values were increased, suggesting that elevation of esterase activity was the underlying mechanism of resistance. Western blots with antisera raised to Est alpha 2(1) and Est beta 2(1) from C. quinquefasciatus indicated that the COL strain had an elevated Est alpha 3 enzyme which co-migrated on native gels with Est beta 1. Southern blots indicated that an est alpha 3 gene was amplified in the COL strain and a Cuban mosquito strain (MRes), although the restriction digest patterns of the est beta 1 genes in these two strains are different. In contrast, the Californian TEMR strain, with the amplified est beta 1(1) gene, had no associated elevated Est alpha. Restriction digest patterns for COL and TEMR DNA suggest that they contain an identical est beta 1(1) gene, but our data suggest that the est alpha 3 gene occurs on the same amplicon as an est beta 1 gene although the genes are probably > 10 kb apart. Hence, either the COL strain has two est beta 1 genes or the est beta 1(1) amplicon in TEMR has been disrupted at some stage during the long colonisation of this strain and the amplified est alpha has been lost.

Animals↗
PubMed1976

The red blood cell esterase D polymorphism in Europe and Asia.

Several regional series from Britain and 3 Asian series were typed for the Esterase D polymorphism. It was found that haemolysates up to 5 years old could be reliably typed when prepared from washed anticoagulated red blood cells. Lysates prepared from blood clots do not retain Esterase D activity quite as well. The Manx population has higher Esterase D 2 gene frequencies than neighbouring populations. A Nepalese population exhibits the highest Esterase D 2 gene frequency so far recorded. The other series presented supplement or confirm results already published.

Asia, Western↗
PubMed1994

Cloning and characterization of the gene encoding an esterase from Spirulina platensis.

The gene encoding a 23 kDA serine esterase from the cyanobacterium Spirulina platensis has been identified, cloned, characterized and expressed in Escherichia coli. The primary structure of the esterase deduced from the DNA sequence displayed 32% sequence identity with the carboxylesterase (esterase II) encoded by estB of Pseudomonas fluorescens; the highest degree of homology is found in a stretch of 11 identical or highly conserved amino acid residues corresponding to the GXSXG consensus motif found in the catalytic site of many serine proteases, lipases and esterases.

Amino Acid Sequence↗
PubMed1986

The effect of growth temperature on esterase patterns in psychrotrophic Bacillus species and other gram-positive genera.

The growth temperature of Bacillus stearothermophilus was previously reported to affect the esterase band pattern obtained after gel electrophoresis. In this study gel electrophoresis of esterases was done on a group of Antarctic bacterial strains cultivated at different temperatures to investigate whether band shift due to a change in growth temperature was a general phenomenon or limited only to select groups. Most strains studied were in the Bacillus genus. Standard strains of known Bacillus species and other Gram-positive genera were examined for comparative purposes. A change in the esterase band pattern was observed as a result of variation in growth temperature. Two major esterase band were dominant in this diverse group of species.

Bacillus↗
PubMed1982

Es-6, a further polymorphic esterase in the rat.

A further polymorphic rat esterase with broad tissue expression and restricted substrate specificity is described and tentatively called Es-6. Inbred rat strains have either fixed allele Es-6F or fixed allele Es-6S. Es-6 is not linked to the established esterase cluster consisting of the eight esterase loci Es-1, Es-2, Es-3M, Es-4M, Es-4W, Es-5 (= Es-3W), Es-7, and Es-8 in LG V of the rat or to RT1, Gc, c, a, and h. Esterases with apparently identical biochemical and genetical characteristics are Es-17 of the mouse and Es-A4 of humans.

Alleles↗
PubMed1984

Genetics of three esterase loci in Anopheles stephensi Liston.

A survey of laboratory strains of Anopheles stephensi for nonspecific esterases by polyacrylamide gel electrophoresis revealed 10 zones of esterase activity. In 3 of the 10 zones, three electromorphs were observed. Genetic analysis revealed that these three zones are controlled by three loci, viz., Est-3, Est-4, and Est-5, and that the electromorphs are codominant alleles at each locus. The three esterase loci were found linked to each other and to an autosomal marker colorless-eye. The esterase loci have tentatively been placed in linkage group II. The probable gene sequence on chromosome 2 is either c-Est-3-Est-4-Est-5 or c-Est-4-Est-3-Est-5.

Animals↗
PubMed1982

Dynamics of non-specific esterase during fat resorption in the jejunum of the house mouse, Mus musculus.

The dynamics of non-specific esterase in the upper duodenum of the house mouse was studied electron microscopically at various intervals following a fat meal. Enterocytic esterase became associated with lipid droplets during fat resorption and formation of primary chylomicrons. Esterase activity remained associated with the primary chylomicrons throughout the process of extrusion into the extracellular space at the lateral interdigitations, and during subsequent transport into the lymph vessels. It is suggested that certain isozymes of non-specific esterase participate in lipid transport.

Animals↗
PubMed1977

The effect of increased crypt cell proliferation on the activity and subcellular localization of esterases and alkaline phosphatase in the rat small intestine.

The activity and ultrastructural localization of alkaline phosphatase and esterase has been studied in normal rat intestine and after the increased crypt cell proliferation that occurs during recovery after 400 rad X-irradiation. Alkaline phosphatase activity is not present in crypt cells of normal intestine, but becomes apparent after the cell has migrated on to the villus. The enzyme is localized in the microvilli, along the lateral cell membranes and in dense bodies. Its activity increases 10 to 15-fold from the base to the tip of the villus. Morphometric analysis of the cell structures where this enzyme is localized reveals no marked changes in their relative proportions during crypt cell development. The expansion of the proliferative cell compartment along the whole length of the crypt which occurs during recovery after irradiation (72 hr after 400 rad X-irradiation) results in a marked reduction of alkaline phosphatase activity in the lower 10-15 cell positions at the base of the villus. During subsequent migration of these cells, the activity increases with cell age but normal values are not attained. From a morphometric analysis it was found that the ultrastructural development is similar to that in controls. These results suggest that during cell maturation, normal values for alkaline phosphatase activity are only attained after 10-12 hr period of maturation in a non-proliferative state and only after the cell has migrated on to the functional villus compartment. In normal intestine, esterase activity shows a 3-fold increase from the bottom to the tip of the crypt and 3 to 4-fold increase during migration up to the middle of the villus. Enzyme activity is localized in the endoplasmic reticulum, the dense bodies and the perinuclear space. Morphometric analyses reveal a 2 to 3-fold increase in the absolute size of these subcellular compartments during crypt cell differentiation and a 2-fold increase at the crypt-villus junction. The relative sizes increase 1-5-fold during crypt cell differentiation and at the time of transition of the cells on to the villus. Increased crypt cell proliferation after irradiation leads to a marked decrease in esterase activity both in crypts and villi. Morphometric analyses of electron micrographs indicate that these changes in activity are not related to any changes in the subcellular structures in which the enzyme is localized. It appears that the normal development of esterase activity depends both on the functional state of the cell and its localization in the crypt or villus.

Alkaline Phosphatase↗
PubMed1980

Esterase polymorphism in a population of Zaprionus paravittiger.

Esterase isozyme variation in Zaprionus paravittiger is controlled by multiple alleles at 2 autosomal loci (Est-1 and Est-3). Est-1 codes for dimeric esterases while Est-3 codes for monomeric esterases. The degree and pattern of esterase polymorphism have been described.

Alleles↗
PubMed1980

Multiple esterase forms in isolated hepatocytes and Kupffer cells of partially hepatectomized rats.

The esterase patterns of isolated parenchymal liver cells of rats consisted of 6 bands of enzymatic activity, whereas the patterns of iron-loaded Kupffer cells showed 5 bands. Both patterns become simpler in the early prereplicative period of liver regeneration. Dukring simultaneous replication of DNA, i.e. 24 h after partial liver removal, an additional band of esterase activity appears in patterns of hepatocytes and Kupffer cells. At the moment of maximum hepatocyte mitotic rate, i.e. 36 h after partial hepatectomy, both esterase patterns lose the single band of activity again. 2 or 3 days after surgery the initial esterase patterns in hepatocytes return whereas the patterns of Kupffer cells remain incomplete.

Animals↗
PubMed1990

Esterase isozymes in a solitary bee, Megachile rotundata (Fab.): characterization, developmental multiplicity, and adult variability.

This study describes the biochemical characterization and genetic variation of cytosolic esterases in the alfalfa leafcutting bee, Megachile rotundata (Fab.). Esterase isozymes were separated by nondenaturing polyacrylamide gel electrophoresis and isoelectric focusing and characterized by inhibition with eserine sulfate, EDTA, paraoxon, and p-hydroxymercuribenzoate. Based on inhibition patterns and substrate specificity, there are major differences between adults and immature forms and more subtle differences between male and female adults. M. rotundata esterases are largely organophosphate sensitive and the two major adult allozymes were highly variable within the population examined. Differences in esterase expression between life stages with respect to niche and the occurrence of diploid males are discussed.

Animals↗
PubMed1988

The genetics and expression of an esterase locus in Anopheles gambiae.

The main polymorphic system of esterase isoenzymes in adults of the G3 laboratory strain of Anopheles gambiae consists of two to five major bands of activity per individual. The bands are designated 5S, 5F, 13, 14, and 15. In genetic crosses, the genes which coded for the bands assorted as three codominant alleles, Est A, Est B, and Est C, at a single autosomal locus. Homozygotes for the Est C allele were significantly underrepresented among backcross progeny. The developmental pattern of esterase expression was examined. Esterase gene expression in embryos was first detectable between 2 and 12 hr after oviposition. The initiation or termination of expression of some of the bands corresponded to boundaries between developmental stages. Most of the esterase fractions were not specifically localized within the tissues tested, with the exception of a series of bands which were restricted largely to adult male testes.

Animals↗
PubMed1976

Inhibition of acid esterase in rat liver by 4,4'-diethylamino-ethoxyhexestrol.

The effect of 4,4'-diethylamino-ethoxyhexestrol (DH) on acid esterase in rat liver was studied in vivo and in vitro. The acid esterase activity in the livers of rats treated with 0.125% DH for 1 week was found to decrease more than 60% as compared with that in untreated rats. The addition of DH to the incubation medium caused considerable inhibition of the acid esterase activity in lysosome from untreated rat liver, and the inhibition type appears to be noncompetitive. The acid lipase activity in rat liver lysosome was also inhibited by DH. Some antihistamic agents and chloroquine also inhibited the acid esterase activity in rat liver lysosome.

Acid Phosphatase↗