An Electron Microscopical Study of the Histochemical Localization of Alkaline Phosphatase in the Cell Wall of Chlorella vulgaris

Brandes, David; Elston, R. N.

doi:10.1038/177274a0

Cited by 25 publications

(7 citation statements)

References 3 publications

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“…The presence of these enzymes indicated the potential to cleave not only susceptible P-O and P-S bonds but also the stronger P-C, P-N, and P-F ones. The location of alkaline phosphatases in tissues was studied by using a histochemical technique; alkaline phosphatases were demonstrated to reside in the cell walls of Chlorella vulgaris and various marine macrophytes (Brandes and Elston 1956;Hernández et al 1994). …”

Section: Esterasesmentioning

confidence: 99%

Bioconcentration, Bioaccumulation, and Metabolism of Pesticides in Aquatic Organisms

Katagi

2009

Reviews of Environmental Contamination and Toxicology

129

102

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The ecotoxicological assessment of pesticide effects in the aquatic environment should normally be based on a deep knowledge of not only the concentration of pesticides and metabolites found but also on the influence of key abiotic and biotic processes that effect rates of dissipation. Although the bioconcentration and bioaccumulation potentials of pesticides in aquatic organisms are conveniently estimated from their hydrophobicity (represented by log K(ow), it is still indispensable to factor in the effects of key abiotic and biotic processes on such pesticides to gain a more precise understanding of how they may have in the natural environment. Relying only on pesticide hydrophobicity may produce an erroneous environmental impact assessment. Several factors affect rates of pesticide dissipation and accumulation in the aquatic environment. Such factors include the amount and type of sediment present in the water and type of diet available to water-dwelling organisms. The particular physiological behavior profiles of aquatic organisms in water, such as capacity for uptake, metabolism, and elimination, are also compelling factors, as is the chemistry of the water. When evaluating pesticide uptake and bioconcentration processes, it is important to know the amount and nature of bottom sediments present and the propensity that the stuffed aquatic organisms have to absorb and process xenobiotics. Extremely hydrophobic pesticides such as the organochlorines and pyrethroids are susceptible to adsorb strongly to dissolved organic matter associated with bottom sediment. Such absorption reduces the bioavailable fraction of pesticide dissolved in the water column and reduces the probable ecotoxicological impact on aquatic organisms living the water. In contrast, sediment dweller may suffer from higher levels of direct exposure to a pesticide, unless it is rapidly degraded in sediment. Metabolism is important to bioconcentration and bioaccumulation processes, as is detoxification and bioactivation. Hydrophobic pesticides that are expected to be highly stored in tissues would not be bioconcentrated if susceptible to biotic transformation by aquatic organisms to more rapidly metabolized to hydrophilic entities are generally less toxic. By analogy, pesticides that are metabolized to similar entities by aquatic species surely are les ecotoxicologically significant. One feature of fish and other aquatic species that makes them more relevant as targets of environmental studies and of regulation is that they may not only become contaminated by pesticides or other chemicals, but that they constitute and important part of the human diet. In this chapter, we provide an overview of the enzymes that are capable of metabolizing or otherwise assisting in the removal of xenobiotics from aquatic species. Many studies have been performed on the enzymes that are responsible for metabolizing xenobiotics. In addition to the use of conventional biochemical methods, such studies on enzymes are increasingly being conducted using immunochemical met...

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Section: Esterasesmentioning

confidence: 99%

Bioconcentration, Bioaccumulation, and Metabolism of Pesticides in Aquatic Organisms

Katagi

2009

Reviews of Environmental Contamination and Toxicology

129

102

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“…Algae Synthesis of phosphatases with external function has been frequently demonstrated in cultured algae (Overbeck, 1962 ;Kuenzler, 1965 ;Kuenzler & Perras, 1965;Healey, 1973;Healey & Hendzel, 1979;Wynne, 1981;Smith & Kalff, 1981). Phosphatases are located on the cell surface (Brandes & Elston, 1956) or in cell membranes (Kuenzler & Perras, 1965, Moller et al, 1975 and the release of extracellular phosphatases in cultures is frequently reported (Healey, 1973 ;Aaronson & Patni, 1976;Patni et al, 1977;Aaronson, 1971;Walther & Fries, 1976;Healey & Hendzel, 1979;Wynne, 198 1).…”

Section: Bacteriamentioning

confidence: 99%

Phosphatases; origin, characteristics and function in lakes

Jansson¹,

Olsson²,

Pettersson³

1988

Hydrobiologia

270

150

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Phosphatases catalyze the liberation of orthophosphate from organic phosphorus compounds. The total phosphatase activity in lake water results from a mixture of phosphatases localized on the cell surfaces of algae and bacteria and from dissolved enzymes supplied by autolysis or .excretion from algae, bacteria and zooplankton. External lake water phosphatases usually have pH optima in the alkaline region. Acid phosphatases generally seem to be active in the internal cell metabolism. The synthesis of external alkaline phosphatases is often repressed at high phosphate concentrations and derepressed at low phosphate concentrations. Phosphatase activity has therefore been used as a phosphorus deficiency indicator in algae and in natural plankton populations. The possibilities for this interpretation of phosphatase activity in lake water are limited, however, and this is discussed. The in situ hydrolysis capacity, i.e. the rate by which orthophosphate is released from natural substrates, is unknown. However, we advocate that this process is important and that the rate of substrate supply, rather than phosphatase activity, limits the enzymatic phosphate regeneration.

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“…In such environments, phosphatases, first demonstrated by Steiner (1938), are produced by bacteria (Jones 1972a, b), algae (Brandes & Elton 1956) and zooplankton (Jansson 1976) . Phosphatases may be associated with seston or exist as dissolved enzymes (Berman 1970 ;Jones 1972a ;Overbeck & Babenzein 1964 ;Reichardt et al 1967) .…”

Section: Introductionmentioning

confidence: 99%

A study on biological activity measurements and heterotrophic bacteria in a small freshwater lake

Tiwari

Mishra

1982

Hydrobiologia

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A 6-m-deep lake has been sampled to measure the temporal and depth-wise distribution of heterotrophic bacteria and biological activity in the water . Surface, mid-depth and bottom waters were analysed at monthly intervals for a period of one year . The coefficient of heterotrophic activity, alkaline phosphatase activity and biological oxygen demand are used as an index of biological activity . The bacterial community was at maximum during spring, coinciding with high values of biological activity . Highest biological activity was observed in the bottom waters . Dissolved organic carbon showed a significant positive correlation with most of the biological activity parameters . This suggests that biological activity, as measured by the coefficient of heterotrophic activity, was more closely related to the concentration of substrates than to population density of heterotrophic bacteria .

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An Electron Microscopical Study of the Histochemical Localization of Alkaline Phosphatase in the Cell Wall of Chlorella vulgaris

Cited by 25 publications

References 3 publications

Bioconcentration, Bioaccumulation, and Metabolism of Pesticides in Aquatic Organisms

Bioconcentration, Bioaccumulation, and Metabolism of Pesticides in Aquatic Organisms

Phosphatases; origin, characteristics and function in lakes

A study on biological activity measurements and heterotrophic bacteria in a small freshwater lake

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