Surface phosphatase activity

Johnson D, Leake JR, Lee JA (1999) The effects of quantity and duration of simulated pollutant nitrogen deposition on root-surface phosphatase activities in calcareous and acid grasslands a bioassay approach. New Phytol 141 433 142. doi http //www.blackwell-synergy.com/doi/ abs/10.1046/j. 1469-8137.1999.00360.x... 

Antibus, R.K., Bower, D. and Dighton, J. (1997) Root surface phosphatase activities and uptake of P-labelled inositol phosphate in field-collected gray birch and red maple roots. Myc-orrhiza 7, 39-45. 

Among the eukaryotic algae, surface phosphatase activity has been reported widely in red, brown and green algae (Whitton, 1991 Hernandez et al., 2003), diatoms (Myklestad and Sakshaug, 1983 Strojsovfi et al., 2003), dinoflagellates (Rivkin and Swift, 1980 Dyhrman and Palenik, 2001 Strojsovfi et al,... 

Fig. 10.3. The relationship between tissue phosphorus concentration and surface phosphatase activity for two mosses growing in Upper Teesdale, northern England. Data are from mosses sampled during an annual cycle and activity is expressed as p,mol para-nitrophenol (pNP) per g dry weight/h. Data taken from Turner etal. (2003a).

The evidence indicates that provision of a large area of wall with high surface phosphatase activity is one, if not the most important, role for these hairs. In all cases where an organism able to develop multicellular hairs was subjected to phosphorus limitation, hairs were formed, though in some taxa they were shown experimentally to form in response to one or several other element limitations such hairs are smaller than those formed under phosphorus limitation and often look slightly different... 

Some cyanobacteria which form hairs in response to phosphorus limitation form less well-developed hairs in response to iron limitation (Sinclair and Whitton, 1977 Douglas et al., 1986), but such hairs do not show phosphomonoesterase activity. Similarly, some green algae which form hairs in response to phosphorus limitation (Whitton and Harding, 1978) form less well-developed hairs in response to nitrogen limitation and occasionally other limitations, but these hairs also do not develop phosphomonoesterase activity (Gibson and Whitton, 1987b Whitton, 1988). However, no example of a field population of a cyanobacterium with hairs has been found which did not show surface phosphatase activity,... 

Christmas, M. and Whitton, B.A. (1 998a) Phosphorus and aquatic bryophytes in the Swale-Ouse river system, North-East England. 1. Relationship between ambient phosphate, internal N P ratio and surface phosphatase activity. Science of the Total Environment 21 0/21 1, 389-399. 

Ellwood, N.T.W., Haile, S.M. and Whitton, B.A. (2002) Surface phosphatase activity of the moss Warnstorfia fluitans as an indicator of the nutrient status of an acidic stream. Verhandlung Inter-nationnale Vereinigung Limnologie 2 8, 62-623. 

Hantke, B. and Melzer, A. (1993) Kinetic changes in surface phosphatase activity of Synedra acus (Bacillariophyceae) in relation to pH variation. Freshwater Biology 29, 31-35. 

Stevenson, P.A.R. (1994) Surface phosphatase activity of Peltigera and Cladonia lichens. MSc thesis, University of Durham, UK. 

Whitton, B.A., Yelloly, J.M., Christmas, M. and Hernandez, I. (1998) Surface phosphatase activity of benthic algae in a stream with highly variable ambient phosphate concentrations. 

Figure 2. Mechanism of PDH. The three different subunits of the PDH complex in the mitochondrial matrix (E, pyruvate decarboxylase E2, dihydrolipoamide acyltrans-ferase Ej, dihydrolipoamide dehydrogenase) catalyze the oxidative decarboxylation of pyruvate to acetyl-CoA and CO2. E, decarboxylates pyruvate and transfers the acetyl-group to lipoamide. Lipoamide is linked to the group of a lysine residue to E2 to form a flexible chain which rotates between the active sites of E, E2, and E3. E2 then transfers the acetyl-group from lipoamide to CoASH leaving the lipoamide in the reduced form. This in turn is oxidized by E3, which is an NAD-dependent (low potential) flavoprotein, completing the catalytic cycle. PDH activity is controlled in two ways by product inhibition by NADH and acetyl-CoA formed from pyruvate (or by P-oxidation), and by inactivation by phosphorylation of Ej by a specific ATP-de-pendent protein kinase associated with the complex, or activation by dephosphorylation by a specific phosphoprotein phosphatase. The phosphatase is activated by increases in the concentration of Ca in the matrix. The combination of insulin with its cell surface receptor activates PDH by activating the phosphatase by an unknown mechanism.

The differentiation effect of lycopene was associated with elevated expression of several differentiation-related proteins, such as cell surface antigen (CD14), oxygen burst oxidase and chemotactic peptide receptors (Amir et al., 1999). Recently, it has also been reported that lycopene was also able to stimulate the differentiation marker alkaline phosphatase activity in... 

In man and in other mammalian species, the major mass of the prostate, usually consisting of the right and left lateral and the middle lobes, is composed of alveoli lined with columnar epithelium embedded in a thick fibromuscular stroma. These alveoli constantly secrete a fluid which is drained off by a system of branching ducts that empty into the floor and lateral surfaces of the posterior urethra. The normal secretion is dependent upon the degree of androgenic stimulation and amounts to about 0.5-2 ml per day. The prostatic secretion, which is characterized by very high acid phosphatase activity, is a milky fluid which contains citric acid, choline, cephalin, cholesterol, proteins, and electrolytes similar to those found in the plasma. 

Sites of alkaline phosphatase activity are frequently in endothelial cells of blood capillaries, mucous glandular cells (F3), microvilli of intestine (C6, CIO, D2, H21, P8, W7), bile canaliculi (D21, F27, W2), and placenta (W3), as well as in the brush border of the lumenal surface of epithelial cells of the proximal convoluted renal tubules (M22, Wl). The location of L-phenylalanine-sensitive alkaline phosphatase in human intestine and placenta is illustrated in Fig. 30. Electron micrographs (Fig. 31) show the details of the alkaline phosphatase, and illustrate the... 

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