Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.26 (invertase)
 4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Stimulation of fluid secretion from fly salivary glands by 5-hydroxytryptamine (5-HT) is known to involve calcium and cyclic AMP. Isolated salivary glands were used to investigate the role of these second messengers in the control of enzyme (sucrase) secretion.2. The protein component of secretion from isolated glands treated with 5-HT appears to be identical to that of saliva secreted by flies during feeding.3. Stimulation of fluid secretion by 5-HT follows a definite dose-response curve, but there is no consistent relationship between the rate of enzyme secretion and the stimulating concentration of 5-HT.4. Exogenous cyclic AMP causes secretion of enzymes as well as of fluid, thus mimicking the action of 5-HT. The phosphodiesterase inhibitor theophylline enhances the rate of 5-HT-stimulated enzyme secretion.5. Removal of calcium from the bathing medium enhances enzyme secretion in response to 5 or 10 nM-5-HT but has no effect on enzyme secretion stimulated by 100 nM-5-HT or by cyclic AMP.6. Addition of 0.1 mM-lanthanum to medium containing 2 mM-calcium mimics the effect of calcium-free solution on 5-HT-stimulated enzyme secretion.7. The ionophore A 23187 causes secretion of both fluid and enzyme. The secretory rate is initially high but soon declines and ceases after about 40 min.8. Enzyme secretion in response to 5-HT or to cyclic AMP is progressively inhibited as the concentration of potassium is increased from 10 to 80 mM. Secretion in response to A 23187 is initially inhibited by 80 mM-potassium but then partially recovers.9. The rate of enzyme secretion appears to be affected by the intracellular concentrations of both calcium and cyclic AMP. It is possible that the rate of enzyme secretion increases as the intracellular calcium concentration rises, until the optimal calcium concentration is reached when further increase in the level of calcium progressively inhibits secretion. The optimal calcium concentration for enzyme secretion is lower than that for fluid secretion, and 5-HT normally causes maximal fluid secretion and submaximal enzyme secretion.
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PMID:The control of enzyme secretion from fly salivary glands. 20 76

The hydrolase content of vacuoles isolated from protoplasts of suspension-cultured tobacco cells, of tulip petals, and of pineapple leaves, and the sedimentation behavior of tobacco tonoplasts were studied. Three precautions were found to be important for the analysis of vacuolar hydrolases and of the tonoplast. (a) Purification of protoplasts in a Ficoll gradient was necessary to remove cell debris which contained contaminating hydrolases adsorbed from the fungal cell-wall-degrading enzyme preparation. (b) Hydrolase activities in the homogenates of the intact cells or the tissue used and of the purified protoplasts had to be compared to verify the absence of contaminating hydrolases in the protoplast preparation. (c) Vacuoles obtained from the protoplasts by an osmotic shock had to be purified from the lysate in a Ficoll gradient. Since the density of the central vacuole approximates that of the protoplasts, about a 10% contamination of the vacuolar preparation by surviving protoplasts could not be eliminated and had to be taken into account when the distribution of enzymes and of radioactivity was calculated.THE INTRACELLULAR ACTIVITIES OF THE FOLLOWING ACID HYDROLASES WERE PRIMARILY LOCALIZED IN THE VACUOLE OF TOBACCO CELLS: alpha-mannosidase, beta-N-acetylglucosaminidase, beta-fructosidase, nuclease, phosphatase, phosphodiesterase. A similar composition of acid hydrolases was found in vacuoles obtained from protoplasts of tulip petals. Proteinase, a hydrolase with low activity in tobacco cells and tulip petals and therefore difficult to localize unequivocally, was found to be vacuolar in pineapple leaves, a tissue containing high levels of this enzyme. Our data support the hypothesis that the central vacuole of higher plant cells has an enzyme composition analogous to that of the animal lysosome.None of the vacuolar enzymes investigated was found to be bound to the tonoplast. When vacuoles were isolated from cells labeled with radioactive choline, the vacuolar membrane was found to contain radioactivity. On sucrose gradients, the label incorporated into tonoplasts banded around a density of 1.10 grams per cubic centimeter (24% sucrose, w/w).
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PMID:Hydrolytic enzymes in the central vacuole of plant cells. 1666 Aug 69

Soil properties, microbial communities and enzyme activities were studied in soil amended with replicase (RP)-transgenic or non-transgenic papaya under field conditions. Compared with non-transgenic papaya, significant differences (P<0.05) were observed in total nitrogen in soils grown with transgenic papaya. There were also significant differences (P<0.05) in the total number of colony forming units (CFUs) of bacteria, actinomycetes and fungi between soils amended with RP-transgenic plants and non-transgenic plants. Compared with non-transgenic papaya, the total CFUs of bacteria, actinomycetes and fungi in soil with transgenic papaya increased by 0.43-1.1, 0.21-0.80 and 0.46-0.73 times respectively. Significantly higher (P<0.05) CFUs of bacteria, actinomycetes and fungi resistant to kanamycin (Km) were obtained in soils with RP-transgenic papaya than those with non-transgenic papaya in all concentrations of Km. Higher resistance quotients for Kmr (kanamycin resistant) bacteria, actinomycetes and fungi were found in soil planted with RP-transgenic papaya, and the resistance quotients for Kmr bacteria, actinomycetes and fungi in soils with transgenic papaya increased 1.6-4.46, 0.63-2.5 and 0.75-2.30 times. RP-transgenic papaya and non-transgenic papaya produced significantly different enzyme activities in arylsulfatase (5.4-5.9x), polyphenol oxidase (0.7-1.4x), invertase (0.5-0.79x), cellulase (0.23-0.35x) and phosphodiesterase (0.16-0.2x). The former three soil enzymes appeared to be more sensitive to the transgenic papaya than the others, and could be useful parameters in assessing the effects of transgenic papaya. Transgenic papaya could alter soil chemical properties, enzyme activities and microbial communities.
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PMID:Field released transgenic papaya effect on soil microbial communities and enzyme activities. 1858 57