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PubMed1988

Population relationships of Simulium yahense and Simulium sanctipauli in the Firestone Rubber Plantation at Harbel, Liberia.

Comparative genetic differences for the phosphoglucomutase and trehalase loci were surveyed in larval and adult blackfly populations of the onchocerciasis vectors Simulium yahense Vajime and Dunbar, and S.sanctipauli Vajime and Dunbar. Genotype frequencies for each stage and all populations were at Hardy-Weinberg equilibrium, indicating that S.yahense and S.sanctipauli remain genetically distinct. S.yahense populations from three different locations were found to be genotypically comparable. The larval population of S.yahense found in closest proximity to a S.sanctipauli population was found to express the phosphoglucomutase allele 1.33, characteristic of S.sanctipauli, with significantly greater frequency than other larval populations of S.yahense. This may constitute evidence of limited genetic introgression of S.sanctipauli with the S.yahense population.

Animals↗
PubMed1993

Trehalose metabolism in Escherichia coli: stress protection and stress regulation of gene expression.

Endogenously synthesized trehalose is a stress protectant in Escherichia coli. Externally supplied trehalose does not serve as a stress protectant, but it can be utilized as the sole source of carbon and energy. Mutants defective in trehalose synthesis display an impaired osmotic tolerance in minimal growth media without glycine betaine, and an impaired stationary-phase-induced heat tolerance. Mechanisms for stress protection by trehalose are discussed. The genes for trehalose-6-phosphate synthase (otsA) and anabolic trehalose-6-phosphate phosphatase (otsB) constitute an operon. Their expression is induced both by osmotic stress and by growth into the stationary phase and depend on the sigma factor encoded by rpoS (katF). rpoS is amber-mutated in E. coli K-12 and its DNA sequence varies among K-12 strains. For trehalose catabolism under osmotic stress E. coli depends on the osmotically inducible periplasmic trehalase (TreA). In the absence of osmotic stress, trehalose induces the formation of an enzyme IITre (TreB) of the group translocation system, a catabolic trehalose-6-phosphate phosphatase (TreE), and an amylotrehalase (TreC) which converts trehalose to free glucose and a glucose polymer.

Base Sequence↗
PubMed1990

Amniotic fluid microvillar enzyme activity in fetal malformations.

Prenatal diagnosis of cystic fibrosis based on amniotic fluid microvillar enzyme activity assay has become routine practice in the past few years. Normal (median) values of these enzymes were determined in 177 normal healthy pregnancies between 15-20 gestational weeks and were related to enzyme values measured in 50 pregnancies complicated with congenital malformations, 6 monogenic inherited diseases and 4 chromosomal aberrations. It is concluded that increased trehalase activity has diagnostic importance in detecting fetal kidney diseases, and radial-renal syndrome (with elevated GGT activity), while low enzyme activities may indicate chromosomal aberrations (with no signs of intestinal obstruction). With the collection of further data, the analysis of these enzymes might provide an opportunity to set up diagnostic procedures for the detection of other, non-CF-related cases.

Alkaline Phosphatase↗
PubMed1987

Changes in the concentration of cAMP, fructose 2,6-bisphosphate and related metabolites and enzymes in Saccharomyces cerevisiae during growth on glucose.

Changes in the concentration of several metabolites and enzymes related to carbohydrate metabolism were measured during the growth of Saccharomyces cerevisiae on a mineral medium containing glucose as the limiting nutrient. When about 50% of the original glucose was used the exponential phase ended and the culture entered a 'transition' phase before the complete exhaustion of glucose. In this transition phase several metabolic changes occurred. cAMP, that decreased along growth, reached a constant value of about 0.7 nmol/g dry weight. A pronounced drop in fructose-6-phosphate-2-kinase activity and in the concentration of fructose 2,6-bisphosphate and fructose 1,6-bisphosphate was observed accompanied by a less marked decrease in hexose monophosphates. Trehalase activity also dropped and reached a minimal value at the onset of the stationary phase when synthesis of trehalose began. Glycogen concentration and glycogen synthase activity increased sharply during the transition phase. Plasma membrane ATPase began to increase at the middle of the exponential phase and then, coincident with the glucose exhaustion, a 90% decrease in the measurable activity was observed.

Adenosine Triphosphatases↗
PubMed1994

The role of trehalose synthesis for the acquisition of thermotolerance in yeast. I. Genetic evidence that trehalose is a thermoprotectant.

In the yeast Saccharomyces cerevisiae, accumulation of the non-reducing disaccharide trehalose is triggered by various stimuli that activate the heat-schock response. Several studies have shown a close correlation between trehalose levels and tolerance to heat stress, suggesting that trehalose may be a protectant which contributes to thermotolerance. In this study, we have examined mutants defective in genes coding for key enzymes involved in trehalose metabolism with respect to the heat-induced and stationary-phase-induced accumulation of trehalose and the acquisition of thermotolerance. Inactivation of either TPS1 or TPS2, encoding subunits of the trehalose-6-phosphate synthase/phosphatase complex, caused an inability to accumulate trehalose upon a mild heat-shock or upon initiation of the stationary phase and significantly reduced the levels of heat-induced and stationary-phase-induced thermotolerance. Deletion of NTH1, the gene coding for the neutral trehalase, resulted in a defect in trehalose mobilization during recovery from a heat shock which was paralleled by an abnormally slow decrease of thermotolerance. Our results provide strong genetic evidence that heat-induced synthesis of trehalose is an important factor for thermotolerance induction. In an accompanying study [Hottiger, T., De Virgilio, C., Hall, M. N., Boller, T. & Wiemken, A. (1993) Eur. J. Biochem. 219, 187-193], we present evidence that the function of heat-induced trehalose accumulation may be to increase the thermal stability of proteins.

Acclimatization↗
PubMed1990

The effect of continued feeding of physiological amounts of lactose on the level of intestinal lactase and other disaccharidase enzyme activities in the rat.

Intestinal lactase activity in mammals is high at birth but begins to decline around weaning and reaches very low levels in adult life. The triggering mechanism for this decline is not clear. Because of the association of the decline with weaning, lack of lactose in the diet has been implicated. In 110 growing rats, the effect of continued supplementation of the diet after weaning with physiological amounts of either cows' milk or a 5% lactose solution on intestinal lactase and other disaccharidase enzyme activities was investigated. In both control and test animals, the specific lactase activity decreased from a peak value of 115 +/- 4 mumol min-1 g-1 protein before weaning to about 10% at maturity. There was no significant difference in the level or the pattern of decline between the groups. Sucrase, maltase and trehalase showed the normal maturational changes without being affected by the test diets. The finding suggests that diet, particularly the presence or absence of physiological amounts of lactose, has no appreciable effect on the age related spontaneous decline of intestinal lactase activity or on the pattern of development of the other disaccharidases.

Aging↗
PubMed1978

Isolation and properties of fecal proteins and fecal alkaline phosphatase from germfree and conventional rats.

Fecal proteins from germfree and conventional rats were isolated. The proteins from the two kinds of feces differed in molecular weight, judging from Sephadex gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The conventional feces contained a greater amount of high-molecular-weight and a lesser amount of low-molecular-weight proteins than did the germfree feces. The fecal proteins of both kinds contained carbohydrates. Both feces contained considerable enzyme activity. The germfree feces contained extremely high activity in alkaline phosphatase and leucine aminopeptidase. Both feces showed the same level of trehalase activity. The conventional feces contained higher levels of activity of protease and acid phosphatase than did the germfree feces. Lactase activity was observed only in the conventional feces. The fecal alkaline phosphatase resembled the intestinal enzyme in response to L-phenylalanine inhibition and urea denaturation. From these results it was inferred that the germfree feces contained some of the intestinal proteins and that the conventional feces contained bacterial proteins in addition to intestinal proteins.

Alkaline Phosphatase↗
PubMed1999

Elevated growth of Saccharomyces cerevisiae ATH1 null mutants on glucose is an artifact of nonmatching auxotrophies of mutant and reference strains.

Yeast strains disrupted for ATH1, which encodes vacuolar acid trehalase, have been reported to grow to higher cell densities than reference strains. We showed that the increase in cell density is due to the URA3 gene introduced as a part of the disruption and concluded that the misinterpretation is a result of not using a control strain with matching auxotrophic markers.

Culture Media↗
PubMed2005

Survival of genetically modified and self-cloned strains of commercial baker's yeast in simulated natural environments: environmental risk assessment.

Although genetic engineering techniques for baker's yeast might improve the yeast's fermentation characteristics, the lack of scientific data on the survival of such strains in natural environments as well as the effects on human health prevent their commercial use. Disruption of acid trehalase gene (ATH1) improves freeze tolerance, which is a crucial characteristic in frozen-dough baking. In this study, ATH1 disruptants constructed by genetic modification (GM) and self-cloning (SC) techniques were used as models to study such effects because these strains have higher freeze tolerance and are expected to be used commercially. Behavior of the strains in simulated natural environments, namely, in soil and water, was studied by measuring the change in the number of viable cells and in the concentration of DNA that contains ATH1 loci. Measurements were made using a real-time PCR method during 40 days of cultivation. Results showed that the number of viable cells of GM and SC strains decreased in a time-dependent manner and that the decrease rate was nearly equal to or higher than that for wild-type (WT) yeast. For all three strains (SC, GM, and WT) in the two simulated natural environments (water and soil), the DNA remained longer than did viable cells but the decrease patterns of either the DNA or the viable cells of SC and GM strains had tendencies similar to those of the WT strain. In conclusion, disruption of ATH1 by genetic engineering apparently does not promote the survival of viable cells and DNA in natural environments.

Cloning, Molecular↗
PubMed1975

Rapid method for preparing cell-free extracts of Aspergillus ochraceus.

A rapid method for preparing cell-free extracts of Aspergillus ochraceus was developed. Mycelial mats were prefrozen in liquid nitrogen, ground to a fine powder in a cold mortar, and homogenized in an all-glass mechanical homogenizer. This method provided preparations averaging 43.0 mg of protein per g of mycelium (wet weight). The method was fast, efficient, and did not subject the extract to temperatures above 1 C or to heavy metals. The preparation method was suitable for studying a variety of in vitro fungal enzyme systems. Amylase, acid phosphate dehydrogenase, beta-glucosidase, beta fructofuranosidase, and trehalase activities were measurable in the preparations.

Acid Phosphatase↗
PubMed2006

Characterization and regulation of the trehalose synthesis pathway and its importance in the pathogenicity of Cryptococcus neoformans.

The disaccharide trehalose has been found to play diverse roles, from energy source to stress protectant, and this sugar is found in organisms as diverse as bacteria, fungi, plants, and invertebrates but not in mammals. Recent studies in the pathobiology of Cryptococcus neoformans identified the presence of a functioning trehalose pathway during infection and suggested its importance for C. neoformans survival in the host. Therefore, in C. neoformans we created null mutants of the trehalose-6-phosphate (T6P) synthase (TPS1), trehalose-6-phophate phosphatase (TPS2), and neutral trehalase (NTH1) genes. We found that both TPS1 and TPS2 are required for high-temperature (37 degrees C) growth and glycolysis but that the block at TPS2 results in the apparent toxic accumulation of T6P, which makes this enzyme a fungicidal target. Sorbitol suppresses the growth defect in the tps1 and tps2 mutants at 37 degrees C, which supports the hypothesis that these sugars (trehalose and sorbitol) act primarily as stress protectants for proteins and membranes during exposure to high temperatures in C. neoformans. The essential nature of this pathway for disease was confirmed when a tps1 mutant strain was found to be avirulent in both rabbits and mice. Furthermore, in the system of the invertebrate C. elegans, in which high in vivo temperature is no longer an environmental factor, attenuation in virulence was still noted with the tps1 mutant, and this supports the hypothesis that the trehalose pathway in C. neoformans is involved in more host survival mechanisms than simply high-temperature stresses and glycolysis. These studies in C. neoformans and previous studies in other pathogenic fungi support the view of the trehalose pathway as a selective fungicidal target for use in antifungal development.

Animals↗
PubMed1972

Cell wall alterations associated with the hyperproduction of extracellular enzymes in Neurospora crassa.

A pleiotropic mutation in Neurospora (exo-1), which confers derepression of alpha-amylase, glucoamylase, beta-fructofuranosidase, and trehalase, appears to also affect the composition of the cell wall. Segregants resulting from the backcross of exo-1 to the wild-type strain from which it derived are altered in the ratio of galactosamine to glucosamine in hydrolysates of isolated cell walls. Conidial cell walls exhibit a marked decrease in the amount of galactosamine in both exo-1 and exo-1(+) strains. Increased levels (approximately sevenfold) of amylase are found in conidia of exo-1, as compared with those of exo-1(+).

Amylases↗
PubMed1987

Heat-induced accumulation and futile cycling of trehalose in Saccharomyces cerevisiae.

Heat shock resulted in rapid accumulation of large amounts of trehalose in Saccharomyces cerevisiae. In cultures growing exponentially on glucose, the trehalose content of the cells increased from 0.01 to 1 g/g of protein within 1 h after the incubation temperature was shifted from 27 to 40 degrees C. When the temperature was readjusted to 27 degrees C, the accumulated trehalose was rapidly degraded. In parallel, the activity of the trehalose-phosphate synthase, the key enzyme of trehalose biosynthesis, increased about sixfold during the heat shock and declined to the normal level after readjustment of the temperature. Surprisingly, the activity of neutral trehalase, the key enzyme of trehalose degradation, also increased about threefold during the heat shock and remained almost constant during recovery of the cells at 27 degrees C. In pulse-labeling experiments with [14C]glucose, trehalose was found to be turned over rapidly in heat-shocked cells, indicating that both anabolic and catabolic enzymes of trehalose metabolism were active in vivo. Possible functions of the heat-induced accumulation of trehalose and its rapid turnover in an apparently futile cycle during heat shock are discussed.

Chromatography, High Pressure Liquid↗
PubMed1990

Glucose-induced hyperaccumulation of cyclic AMP and defective glucose repression in yeast strains with reduced activity of cyclic AMP-dependent protein kinase.

Addition of glucose or related fermentable sugars to derepressed cells of the yeast Saccharomyces cerevisiae triggers a RAS-mediated cyclic AMP (cAMP) signal that induces a protein phosphorylation cascade. In yeast mutants (tpk1w1, tpk2w1, and tpk3w1) containing reduced activity of cAMP-dependent protein kinase, fermentable sugars, as opposed to nonfermentable carbon sources, induced a permanent hyperaccumulation of cAMP. This finding confirms previous conclusions that fermentable sugars are specific stimulators of cAMP synthesis in yeast cells. Despite the huge cAMP levels present in these mutants, deletion of the gene (BCY1) coding for the regulatory subunit of cAMP-dependent protein kinase severely reduced hyperaccumulation of cAMP. Glucose-induced hyperaccumulation of cAMP was also observed in exponential-phase glucose-grown cells of the tpklw1 and tpk2w1 strains but not the tpk3w1 strain even though addition of glucose to glucose-repressed wild-type cells did not induce a cAMP signal. Investigation of mitochondrial respiration by in vivo 31P nuclear magnetic resonance spectroscopy showed the tpk1w1 and tpk2w1 strains, to be defective in glucose repression. These results are consistent with the idea that the signal transmission pathway from glucose to adenyl cyclase contains a glucose-repressible protein. They also show that a certain level of cAMP-dependent protein phosphorylation is required for glucose repression. Investigation of the glucose-induced cAMP signal and glucose-induced activation of trehalase in derepressed cells of strains containing only one of the wild-type TPK genes indicates that the transient nature of the cAMP signal is due to feedback inhibition by cAMP-dependent protein kinase.

Adenosine Triphosphate↗
PubMed1975

Influence of exocrine and endocrine pancreatic function on intestinal brush border enaymatic activities.

Digestive enzymatic activities (disaccharidases, alkaline phosphatase, peptide hydrolases) have been determined in the mucosa of 14 patients with chronic pancreatitis. All had an abnormal secretin-pancreozymin test. Four patients had insulin-dependent diabetes mellitus, four a pathological glucose tolerance test. Nine patients had steatorrhoea. Maltase, sucrase, and alkaline phosphatase activity was significantly elevated in patients with exocrine pancreatic insufficiency, whereas those of lactase, trehalase, and peptide hydrolase were normal. Patients with steatorrhoea had higher maltase and sucrase activity than those without steatorrhoea, whereas decreased glucose tolerance had no effect on brush border enzymatic activity. It is suggested thatdecreased exocrine rather than decreased endocrine pancreatic function is responsible for the increase in intestinal disaccharidase and alkaline phosphatase activity, possible by the influence of pacreatic enzymes on the turnover of brush border enzymes from the luminal side of the mucosal membranes or by direct hormonal stimulation though cholecystokinin.

Adult↗
PubMed1976

Competition between Phytophthora cinnamomi and Trichoderma spp. in autoclaved soil.

Results from analyses of beta-glucosidase (EC 3.2.1.21) and phosphatase (EC 3.1.3.1;EC 3.1.3.2) activities indicated that presence of a Trichoderma isolate reduced development of Phytophthora cinnamomi. It was also observed that P. cinnamomi was more competitive in coinoculated cultures than in cultures where Trichoderma was added on day 3. Analysis of trehalase (EC 3.2.1.28) activity indicated that Trichoderma either utilized portions of the P. cinnamomi mycelium as substrate or the action of P. cinnamomi released additional nutrients not normally available to Trichoderma. Ther stronger Trichoderma isolate was T. harzianum.

Acid Phosphatase↗
PubMed1995

Increased thermal stability of the enzyme content in permeabilized whole cells from the fission yeast Schizosaccharomyces pombe by exogenous trehalose and other compounds.

Cells of the fission yeast Schizosaccharomyces pombe were permeabilized by treatment with toluene-ethanol. The permeabilized cells lost the bulk of the internal trehalose pool while most of the alkaline phosphatase, invertase, alpha-glucosidase, or neutral trehalase activities located inside the cells remained unaffected. This system was used as an in situ assay to determine the involvement of trehalose in enzyme protection during thermal treatments. The addition of trehalose to suspensions of permeabilized cells resulted in a sugar-dependent thermoprotection of the internal marker enzymes. This approach demonstrates that in whole cells of the fission yeast trehalose plays a physiological role as a protective molecule against thermal denaturation of cellular enzymes.

Alkaline Phosphatase↗
PubMedDate not supplied

Fractionation of renal brush border membrane proteins with Triton X-114 phase partitioning.

Analysis of brush border membrane proteins by gel electrophoresis has revealed a complex polypeptide composition. We have investigated the use of Triton X-114 phase partitioning to fractionate such proteins on the basis of their degree of hydrophobicity. Each of the fractions was composed of a complex but distinct set of proteins. Most proteins were solubilized by Triton X-114 and partitioned into the detergent-poor fraction. Trehalase, gamma-glutamyl transpeptidase, and leucine aminopeptidase were well solubilized (greater than 80%) and enriched 5.1-, 3.9-, and 2.5-fold in the detergent-rich fraction. In contrast, alkaline phosphatase and 5'-nucleotidase were poorly solubilized. The specific activities of these enzymes were increased 2.7- and 2.3-fold in the insoluble protein fraction. Maltase was almost completely solubilized and partitioned into the detergent-poor fraction with a small enrichment factor (1.3). These results suggest that Triton X-114 phase partitioning could be useful as a first step in the purification of many brush border membrane proteins.

5'-Nucleotidase↗