Effect of copper on the activation of the acid phosphatase from the green algae Pseudokirchneriella subcapitata

Abstract

The presence of copper in water environment may have detrimental effects on aquatic organisms, including algae, where different enzymatic systems can be affected. Algae acid phosphatase plays important roles in metabolic processes such as decomposition of organic phosphate, autophagic digestive process, recycling cellular materials and zygote formation during reproduction. This work describes an in vitro activation effect of copper on the acid phosphatase of the green algae Pseudokirchneriella subcapitata (formely Selenastrum capricornutum) under preincubation condition. Apparent Michaelis constant values of 1.21 and 0.37 mM, and activation energy values of 26.8 and 13.6 kJ mol(-1) were determined in the absence and in the presence of 0.2 mM Cu(2+), respectively. The dissociation constant value for Cu(2+) binding to the enzyme was determined to be 22.04 microM. The decrease of the apparent Michaelis constant (Km) and activation energy values in the presence of Cu(2+) correlates well with its activating effect on the acid phosphatase activity. This propriety could be used as a sensitive bioindicator for copper in environmental samples.

One-year monitoring of core biomarker and digestive enzyme responses in transplanted zebra mussels (Dreissena polymorpha)

“…Similar inductions have been reported for zebra mussels from Lake Lugano (Italy) (Binelli et al 2005), probably as a result of Cu exposure as already noted in fish species (Dethloff et al 1999;Romani et al 2003). Enhanced AChE activity might be related to interactions of copper ions with AChE enzyme, substrate and coenzymes, resulting in protection of the enzyme against thermal inactivation, increased enzyme-substrate affinity or reduced energy activation (Jonsson and Aoyama 2010). As Cu levels in transplanted mussels (15.7-41.4 lg g -1 dw) were very similar to those recorded in mussels from Lake Lugano (17.5-36.2 lg g -1 dw) (Camusso et al 2001), increased AChE activities noticed in transplanted mussels could be related to the Cu load of the Vesle and Ardre rivers.…”

The use of immobilised metal affinity chromatography (IMAC) to compare expression of copper-binding proteins in control and copper-exposed marine microalgae

“…Unconcentrated eluted protein typically yielded <0.2 mg protein/ml (estimated by A280 nm in a quartz micro-cuvette) from 5 to 10 x 10 8 cells and was concentrated to ≥3 mg protein/ml to facilitate subsequent analysis by SDS-PAGE. The two smaller brown pennate diatoms (C. closterium and P. tricornutum, cell volume 50-70 µm 3 [1,5]) required much higher cell numbers (~ 1 x 10 9 cells) to yield a similar amount of copper binding protein as the larger green microalgae (~ 5 x 10 8 cells) D.…”

“…tertiolecta and Tetraselmis sp. (cell volume 300 ± 100 µm 3 [1,5]). This is not suprising given the disparity in cell sizes, as the green algae have more than three times the cell volume of the diatoms.…”

“…Over the last century, the increasing use of copper in industrial activities (e.g. antifouling paints, algicide, fertilizer and pesticides [2]) and its presence in mining by-products, have seen an increase in the amount of copper being released into the aquatic environment [3].…”

Environmental toxicity: Exposure and impact of chromium on cyanobacterial species

“…It has been found out that cyanobacteria contribute upto one half of annual nitrogen budget in some eutrophic lakes and are significantly important for rice fields. There are several other studies showing the effects of metals on growth, carbon fixation and nitrogenase activiy in algae, which are again species dependent [6][7][8][9][10][11][12]. Comparative evaluation has also been done by researchers with free and immobilized algae in terms of efficiency for metal biosorption [13].…”