The Mechanism of Lysis of Prymnesium parvum by Weak Electrolytes

Abstract

SUMMARYOrganisms of the phytoflagellate Pryrnnesium parvum Carter undergo swelling and lysis in the presence of ammonia or acetic acid. The lytic activity was pH-dependent and increased as the concentration of undissociated weak electrolyte in the suspension medium was increased. The kinetics of swelling were followed with the aid of an electronic particle counter and by microscopic examination. In the presence of ammonia or acetic acid, the rate of swelling as well as the final volume of the Prymnesium organisms were a function of external osmotic pressure and of temperature. It is suggested that the swelling and lysis are osmotic in nature and depend on the intracellular accumulation of weak electrolytes by a 'pump' driven by differences between environmental and intracellular pH values. The similarities between this phenomenon and concentration of weak electrolytes in mammalian erythrocytes and other cells is discussed. Differences in the morphology and lysis of Prymnesium by ammonia and acetic acid were found which suggest the existence of intracellular compartments maintained at different pH values.

Uptake and accumulation of putrescine and its lethality in Anacystis nidulans.

“…5 and 6; J. Gibson, unpublished results) which are permeable in the uncharged form but are impermeable when charged. This mechanism of accumulation (ion trapping or diffusion trapping) also accounts for the concentration of NH3 in green algae (7) and bicarbonate in chloroplasts (8). An analysis of the kinetics of putrescine uptake and of the equilibrium concentration of accumulated putrescine within the cell as a function of the pH of the medium and external concentration of putrescine is consistent with the theory that the concentration of putrescine is due to diffusion of the neutral molecule and trapping of the charged ion.…”

Changes in cell turgor pressure related to uptake of solutes by Microcystis sp. strain 8401

“…The imbalance can be used to measure the internal pH (Falkner et al ., 1976; Rottenberg, 1979; Walsby, 1982). Ammonia, though less basic, can also be accumulated in this way (NH 3 +H 2 0→NH 4 OH→NH 4 + +OH − ); the osmotic swelling that it causes has been used to lyse flagellates (Shilo & Shilo, 1962), with an application in the control of toxic chrysophytes in fish ponds (Shilo, 1971). There was, however, no evidence of such uptake in Microcystis from the measurements made here on turgor pressure in cells suspended in ammonium ions at pH 10.…”

“…NH 4 OH! NH 4 1 1OH À ); the osmotic swelling that it causes has been used to lyse flagellates (Shilo & Shilo, 1962), with an application in the control of toxic chrysophytes in fish ponds (Shilo, 1971). There was, however, no evidence of such uptake in Microcystis from the measurements made here on turgor pressure in cells suspended in ammonium ions at pH 10.…”

Can solar powered circulation control Prymnesium parvum blooms and toxicity in fish hatchery ponds?

“…If that were the case, we would expect either inhibition of P. parvum population growth, toxin production, or toxin activation, or combinations of these actions. Conductivity influences the establishment of P. parvum populations (Shilo and Shilo, 1962;Sarig, 1971). Inorganic P and N concentrations determine whether P. parvum growth is inhibited or promoted and the onset of toxin production (Uronen et al, 2005;Johansson and Grané li, 1999;Legrand, 2001;Grané li and Johansson, 2003;Kurten et al, 2010).…”