Synthesis Of Phosphatases Research Articles

The in vitro synthesis and secretion of alkaline phosphatase from first trimester human decidua

We studied the in vitro synthesis and secretion of alkaline phosphatase by human first trimester decidual tissue incubated in organ culture. Decidua synthesizes two different alkaline phosphatase isoenzymes: heat stable and heat labile. Decidual tissue maintains a constant pool of alkaline phosphatases. The synthesis of alkaline phosphatase may be the driving force for its secretion. The de novo synthesis and secretion rates of alkaline phosphatases were also investigated. The higher specific radioactivities of the secreted enzymes than those found in the tissue may suggest that newly synthesized alkaline phosphatase is preferentially released. The intracellular distribution of the alkaline phosphatase isoenzymes was compared as well. The characteristics of the two isoenzymes are different in human decidua of maternal origin from those previously reported in the human placenta originating from embryonic stem cells.

Synthesis and secretion of alkaline phosphatase in vitro from first-trimester and term human placentas.

The synthesis and secretion of alkaline phosphatases in vitro by human placental tissue incubated in organ culture were studied. First-trimester placenta synthesizes and secretes two different alkaline phosphatase isoenzymes (heat-labile and heat-stable), whereas in term placenta nearly all the alkaline phosphatase synthesized and secreted is heat-stable. The specific activities of alkaline phosphatases in first-trimester and term placental tissue remain constant throughout the time course of incubation. In the media, specific activities increase with time. Hence, alkaline phosphatase synthesis seems to be the driving force for its own secretion. The rates of synthesis de novo and of alkaline phosphatases were measured. The specific radioactivities of the secreted alkaline phosphatases were higher than the corresponding specific radioactivities in the tissue throughout the entire incubation period. The intracellular distribution of the alkaline phosphatase isoenzymes was compared.

Phosphate utilization and constitutive synthesis of phosphatases in Thermoactinomyces vulgaris Tsilinsky.

Thermoactinomyces vulgaris utilized both organic and inorganic phosphates with equal efficiency for its growth. The specific activities of the thermophilic acid and alkaline phosphatases were found to be maximum at 1 mM concentration of each phosphate source. All the phosphatase isoenzymes (three alkaline and one acidic) were observed irrespective of the substrate source and concentration, suggesting constitutive synthesis of the enzymes. During growth and differentiation, both acid and alkaline phosphatases exhibited uniformly stable patterns of isoenzymes with slight variations in their specific activities.

Induced synthesis of phosphatases in Anacystis nidulans by p-NO2-phenylserinal.

Induced synthesis of phosphatases in Anacystis nidulans by p-NO2-phenylserinal.

Induced synthesis of phosphatases in microalgae by antibiotic inhibitor of protein synthesis: Mechanism of action

Massive synthesis of phosphatases induced by antibiotic inhibitors of protein synthesis can be shown in microalgae by biochemical methods. These results confirm those that we have previously obtained by cytochemical methods. The mechanism of action of the antibiotics, in this case, could prevent the penetration of inorganic phosphorus into the cell, before acting on the protein synthesising system. This suggests a new way in which antibiotics may be used to study cell membranes.

The effect of translation and transcription inhibitors on the synthesis of periplasmic phosphatases in E. coli.

Previous studies by others have indicated that the synthesis of secreted enzymes is unusually sensitive to many translation inhibitors and resistant, for about 30 min, to rifampicin. We have studied the sensitivity of secreted (periplasmic) phosphatases to such inhibitors. Alkaline phosphatase synthesis is more sensitive than total protein synthesis to tetracyclin and spectinomycin, but not to sparsomycin, streptomycin, chloramphenicol, kasugamycin, blasticidin S or thiostrepton; it is slightly more resistant than total protein synthesis to the latter two antibiotics. Acid hexose-phosphatase was also preferentially sensitive to tetracyclin and spectinomycin and also to kasugamycin. beta-galactosidase was also included in the study, as an intracellular enzyme, and was found to be preferentially inhibited ("repressed"), sometimes transiently, by all eight translation inhibitors. This effect did not seem to be mediated through cyclic AMP or guanosine tetraphosphate; the "repression" was still evident in mutants with altered rho factor indicating that it may also not be related to artificial polarity. Synthesis of both periplasmic phosphatases was immediately inhibited by rifampicin. These results differ from those found in previous studies with other organisms and suggest a reappraisal of the usual interpretation of these phenomena.

Effect of temperature on the mineralization of organic phosphorus compounds by certain aquatic bacteria

Summary“Yellow pigmented” bacteria chiefly consisting of Flavobacterium species and nonfruiting myxobacteria have been observed as an essential constituent of bacterioplankton in lakes. In eutrophic Mindel Lake (near Constance, BRD) aerobic myxobacteria of allochthonous origin had produced a bacterial waterbloom which persisted longer than 2 months.Isolated strains did not form fruiting bodies under the employed culture conditions and were in most features identical to “Sporocytophaga cauliformis” Knorr & Gräf. These bacteria did not only grow at 0° C, but had a continuous optimum for growth below 20° C.Producing an overplus of alkaline phosphatases they had a marked effect on hydrolysis of phosphates. In spite of their psychrophilic habit synthesis of alkaline phosphatases did not vary at different growth temperatures, and optimum activities were found near 36° C.Pure culture experiments were undertaken to estimate catalytic efficiencies of phosphate mineralization which could be attributed to standing crops of Myxobacteria in lake water.

Genetic control of the synthesis of repressible phosphatases in Neurospora crassa.

Genetic control of the synthesis of repressible phosphatases in Neurospora crassa.

Linear synthesis of sucrase and phosphatases during the cell cycle of Schizosaccharomyces pombe.

ABSTRACT The synthesis of sucrase, acid phosphatase and alkaline phosphatase has been followed in synchronous cultures of the fission yeast Schizosaccharomyces pombe prepared by gradient sedimentation. These three enzymes follow a linear pattern of synthesis through the cell cycle, with a doubling in rate at a ‘critical point’ about one-fifth of the way through the cycle. Sucrasecan be rapidly derepressed by lowering the glucose concentration in the medium. This has been used to measure the sucrase ‘potential’ or capacity to synthesize sucrase on derepression. The potential exists at all times in the cycle, and follows a stepwise pattern with a sharp rise at the critical point. These results suggest that the functional genome doubles at the critical point. Since, however, the period of DNA synthesis is nearly one-third of a cycle before this point, there must be an appreciable delay between chemical replication and functional replication of the genome. In this respect S. pombe, a eukaryotic cell, differs markedly from bacteria. Other physiological events take place near the critical point, and a tentative model is suggested of what may be happening at the chromosomal level. Experiments with cycloheximide indicate that there is a delay between the synthesis and the appearance of the active enzyme in the case of sucrase and alkaline phosphatase.

Repressed and derepressed synthesis of phosphatases during synchronous growth of Chorella pyrenoidosa

Synchronized cultures of the green alga Chlorella pyrenoidosa were used to study the repressed and derepressed synthesis of acid and alkaline phosphatases. These enzymes were synthesized stepwise during the cell's life cycle, the synthesis being derepressed after removal of orthophosphate from the growth medium. Derepression of enzyme synthesis at different times during the life cycle showed that the rates of derepressed enzyme synthesis varied with cell age. A decrease in rate parallel with the mitotic activity was observed.

Rates of synthesis of acid phosphatases in nucleate and enucleate acetabularia fragments

Quantitative studies on a family of acid phosphatase isozymes in nucleate and enucleate Acetabularia mediterranea fragments have been performed. A photometric method of measuring enzyme activity visualized as a lead sulfide deposit on agar electrophoretic plates is described. Five isozymes were found; three had activities large enough to quantify. Preliminary studies were made on the specificity of these enzymes. In nucleate fragments these enzymes appear to be correlated in activity with the rate of growth in length of the organism and the appearance of the apical cap. In enucleate fragments there is no increase in total protein after the tenth post-surgical day, but an apical cap may still be formed. Two of the three enzymes measured increased in activity at the time of cap formation in enucleate plants. The third continued to decrease in activity throughout the experiment. The first two enzymes are associated in large part with chloroplasts and mitochondria, the third is not. It is concluded that the rate of increase in activity of the first two enzymes is not limited by the rate of synthesis of m-RNA by the nucleus.