Alkaline phosphatase

About: Alkaline phosphatase is a research topic. Over the lifetime, 20218 publications have been published within this topic receiving 540547 citations. The topic is also known as: Alkaline_phosphatase & IPR001952.

Influence of phosphate depletion on the growth and colony formation of Phaeocystis pouchetii

Abstract: The haptophycean alga Phaeocystis pouchetii (Hariot) Lagerheim, a bloom-forming species in the North Sea, formed massive colonies in batch cultures only when the phosphate concentration in the medium was below 1 μmol l-1. In general, colony cells and single cells showed a similar response to phosphate depletion: decreased cellular phosphate (up to a factor of 32), decreased chlorophyll-a concentration (up to a factor of 4.2) and high activities of alkaline phosphatase (APA). However, the growth rate of colony cells was reduced at low phosphate concentrations (<1 μmol l-1) in contrast to that of single cells. Colony cells tended to have a slightly higher phosphate concentration than single cells, while the increase in APA was delayed. The differences between single cells and colonies in phosphate utilization, cellular phosphate content, and growth rate cause, at low phosphate levels, a shift towards the formation of colonies. Similar changes seem to occur in nature during transition of nutrient-sufficient to nutrientlimited conditions.

Culture and behavior of osteoblastic cells isolated from normal trabecular bone surfaces

Abstract: We report the characterization of human osteoblastic cells that were derived from the surface of trabecular bone fragments. After removal of bone marrow cells, the bone lining osteoblastic cells lining the bone surface were obtained by migration and proliferation from the trabecular surface onto a nylon mesh. The isolated population proliferated in culture and exhibited osteoblastic phenotype. Cultured cells show a regular arrangment in vitro and exhibited multiple interconnecting junctions on scanning electron microscopic examination. Immunocytochemical staining showed that the cells produced almost exclusively type I collagen. Bone-surface-derived cells responded to 1–34 human parathyroid hormone by increasing intracellular cyclic AMP. Cell cultures exhibited high alkaline phosphatase activity, which was unaffected by 1,25 (OH)2 vitamin D. Untreated cells produced high levels of osteocalcin, a bone-specific protein, and they responded to 1,25(OH) vitamin D by increasing osteocalcin synthesis in a dose-dependent manner. Although cells cultured for up to 5 mo. still produced osteocalcin, the response to 1,25(OH)2D decreased after multiple passages. This study shows that the bone cell populations isolated from trabecular bone surface are enriched in osteoblast precursors and mature osteoblstic cells.

A histochemical study of phagocytic and enzymatic functions of rabbit mononuclear and polymorphonuclear exudate cells and alveolar macrophages. I. Survey and quantitation of enzymes, and states of cellular activation.

Abstract: The cytochrome oxidase (CO), aminopeptidase (AMP), succinic dehydrogenase (SD), acid phosphatase, esterase, and alkaline phosphatase of rabbit mononuclear (MN) and polymorphonuclear (PMN) peritoneal exudate cells and pulmonary alveolar macrophages (AM) - air dried on Mylar strips - were characterized by histochemical techniques with respect to stability, activators, inhibitors, and pH optima. A granule count method was established for the quantitation of these enzymes. For the acid phosphatase of MN, in which the most precise results were obtained, time, pH, substrate, and inhibitor curves resembled those commonly obtained biochemically. Five of these enzymes were usually more active in AM than MN, whereas the sixth, alkaline phosphatase, was not present in either cell type. AM also tended to consume more oxygen than MN and to divide more frequently. Since the most active cells in the population would be first involved in the host's defense against microbial agents, a comparison was made of the 10 per cent of the AM and MN with the highest enzymatic activities. No differences were found in the granule counts that were not reflected by the means. However, within a given AM population, cells containing ingested dust particles seemed to have higher enzymatic activities than those without particles. MN had greater acid phosphatase and SD activities than PMN and consumed more oxygen, but the CO, AMP, and esterase activites of both types of cells were of similar magnitude. PMN showed high alkaline phosphatase activity; MN showed none. A survey of the histochemical literature indicates that a positive correlation between the enzymatic and phagocytic activities of both MN and PMN exists in vivo .

Heat-labile alkaline phosphatase from Antarctic bacteria: Rapid 5′ end-labeling of nucleic acids

Abstract: A heat-labile alkaline phosphatase has been purified to near homogeneity from HK47, a bacterial strain isolated from Antarctic seawater. The active form of the enzyme has a molecular weight of 68,000 and is uniquely monomeric. The optimal temperature for the enzymatic activity is 25°C. Complete and irreversible thermal inactivation of the enzyme occurs in 10 min at 55°C. By using this heat-labile enzyme for dephosphorylation followed by a 10-min heat treatment, rapid end-labeling of nucleic acids by T4 polynucleotide kinase has been achieved.