The role of surface and extracellular phosphatases in the phosphorus requirement of Ochromonas1

Aaronson, S.; Patni, N. J.

doi:10.4319/lo.1976.21.6.0838

Cited by 59 publications

(24 citation statements)

References 16 publications

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“…has been cited as a means by which the phytoplankton may utilize soluble organic P (Kuenzlcr and Perras 1965; Aaronson and Patni 1976), although it is unclear to what extent naturally occurring forms of organic P are hydrolyzable (Herbes 1975).…”

Section: Resultsmentioning

confidence: 99%

A comparison of the abilities of freshwater algae and bacteria to acquire and retain phosphorus1

Currie

Kalff

1984

Limnology & Oceanography

315

188

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Extant physiological and in situ data provide contradictory answers to the question of whether the bacterioplankton can outcompete the phytoplankton for phosphorus at natural concentrations. Two phytoplankton species and three bacterial spccics isolated from the epilimnion of Lake Memphremagog, Quebec, were grown in phosphorus-limited continuous cultures and their abilities to take up and retain phosphorus compared. The algae showed orthophosphate uptake kinetics comparable to those reported elsewhere. In contrast, the specific orthophosphate uptake rates (i.c. uptake per unit cell P) by the bacteria were variable, but much higher than the algal rates at the low P concentrations characteristic of natural waters. Algal and bacterial alkaline phosphatase activities were similar and provided no evidence that the algae could utilize organic P more efficiently than the bacteria. The bacteria showed some tendency to excrete P more readily than the algae but mixed culture experiments indicated that excretion did little to alter the long term partitioning of phosphorus between the algae and the bacteria. The kinetic data suggest that planktonic bacteria are unlikely to be limited by phosphorus in situ. Furthermore, our results are consistent with the hypothesis that the bacteria should bc markedly superior competitors at natural phosphate concentrations.

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Section: Resultsmentioning

confidence: 99%

A comparison of the abilities of freshwater algae and bacteria to acquire and retain phosphorus1

Currie

Kalff

1984

Limnology & Oceanography

315

188

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“…On the one hand, orthophosphate dissolved in water competes with substrates, leading to an inhibition of the activity (Pettersson, 1980). On the other hand, intracellular orthophosphate regulates this activity: in most microbial and algal systems, P depletion of the cells leads to the synthesis of alkaline phosphatases (Aaronson & Patni, 1976). Previous studies demonstrated contrasting results relative to this sensitivity to phosphate.…”

Section: Effect Of Metal Ions and Edtamentioning

confidence: 99%

Physico-chemical properties of Alkaline Phosphatases released by a Planktonic Crustacean, Daphnia Magna (Cladocera)

Zhao¹,

Liu²,

Hu³

2006

Crustac

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Our studies investigated the physico-chemical properties of alkaline phosphatase excreted by D. magna. This cladoceran mainly released alkaline phosphatase, though it also released a small amount of acid phosphatase. The alkaline phosphatase showed a broad pH optimum (8.05-10.0), and had a broad optimum temperature (30-35 • C) with a temperature coefficient (Q 10 ) of 2.45. The K m of the enzyme is 0.15 ± 0.02 mM when p-nitrophenyl phosphate is used as a substrate, and the V max is 0.43 ± 0.01 µM pNP mg −1 DW h −1 . Even though alkaline phosphatase had been incubated in chloroform saturated with WC medium for 13 days, its activity was 54% that of the original. The enzyme was strongly inactivated by EDTA, and appeared to be zinc dependent. The alkaline phosphatase activity remained constant when D. magna was fed different quantities of Chlorella sp. The sensitivity of D. magna phosphatase activity to phosphate was time-dependent. During the first 16 hrs, the enzyme was insensitive to phosphate addition, after 24 hrs incubation the enzyme became sensitive to phosphate addition. RÉSUMÉNos études ont porté sur les propriétés physico-chimiques de la phosphatase alcaline excrétée par Daphnia magna. Ce cladocère libère principalement une phosphatase alcaline, bien qu'elle excrète aussi une petite quantité de phosphatase acide. La phosphatase alcaline présentait un large optimum de pH (8,05-10,0) et une température optimum étendue (30-35 • C) avec un coefficient de température (Q 10 ) de 2,45. Le K m de l'enzyme est de 0,15 ± 0,02 mM quand le phosphate de p-nitrophényle est utilisé comme substrat, et le V max est de 0,43 ± 0,01 µM pNP mg −1 DW h −1 . Même lorsque la phosphatase alcaline était incubée dans du chloroforme saturé avec un milieu WC pendant 13 jours,3 )

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“…Washed cells were resuspended in starvation medium (Aaronson & Patni, 1976) containing different concentrations of chloramphenicol or chloramphenicol base. At intervals, acid phosphatase activity was determined using p-nitrophenyl pfiosphate as an assay substrate.…”

Section: S a A R O N S O N And N J P A T N I Table 1 Efect Of Chlmentioning

confidence: 99%

“…Percentage increase in enzyme activity over zero-time sample after: experiments have been described elsewhere (Aaronson & Patni, 1976). Details of the radioactive labelling experiments with [3H]leucine were described by Patni & Aaronson (1977).…”

Section: S a A R O N S O N And N J P A T N I Table 1 Efect Of Chlmentioning

confidence: 99%

Stimulation of Acid Phosphatase Synthesis and Secretion in Ochromonas danica by Chloramphenicol Base

Aaronson¹,

Patni²

1978

Journal of General Microbiology

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The role of surface and extracellular phosphatases in the phosphorus requirement of Ochromonas1

Cited by 59 publications

References 16 publications

A comparison of the abilities of freshwater algae and bacteria to acquire and retain phosphorus1

A comparison of the abilities of freshwater algae and bacteria to acquire and retain phosphorus1

Physico-chemical properties of Alkaline Phosphatases released by a Planktonic Crustacean, Daphnia Magna (Cladocera)

Stimulation of Acid Phosphatase Synthesis and Secretion in Ochromonas danica by Chloramphenicol Base

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