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Journal ArticleDOI

The active transport of ions in plant cells.

01 Aug 1970-Quarterly Reviews of Biophysics (Cambridge University Press)-Vol. 3, Iss: 3, pp 251-294
TL;DR: The present review indicates the existence of similar ion transports in higher plant cells, but it does not present a complete review of the experimental work on higher plants, and tries to assess progress towards understanding the mechanisms involved.
Abstract: In a recent review of the transport of salts and water across multicellular secretory tissues in animals (Keynes, 1969), a summary was given of the various types of active transport of ions necessary to explain the experimental observations in a very wide range of tissues, and five basic types of ion pump were discussed The question of whether plants and animals have any common mechanisms for the transport of salts and water was specifically excluded The original aim of the present review was to survey the types of ion pump found in plant cells and tissues, and to compare these with those found in animals Its aims narrowed very considerably in writing It now reviews ion transport processes in giant algal cells, and tries to assess progress towards understanding the mechanisms involved It indicates the existence of similar ion transports in higher plant cells, but it does not present a complete review of the experimental work on higher plants
Citations
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Journal ArticleDOI
TL;DR: This comprehensive literature review of the phosphorus nutrition and metabolism of eukaryotic microalgae deals sequentially with extracellular P-compounds available for algal utilization and growth and includes specific macroalgae in considering certain subtopics where such algae were better investigated and provided a good basis for comparison.
Abstract: This comprehensive literature review of the phosphorus nutrition and metabolism of eukaryotic microalgae deals sequentially with (1) extracellular P-compounds available for algal utilization and growth; (2) orthophosphate uptake mechanisms, kinetics, and influence from environmental variables; (3) phosphatase-mediated utilization of organic phosphates involving multiple enzymes, induction and cellular location of repressible and irrepressible phosphatases, and their role in growth physiological processes; (4) intracellular phosphate metabolism covering diversity of phosphometabolites. ATP-linked energy regulation, polyphosphate pools and storage roles, phospholipids and phospholipases; (5) steady-state and transient-state models relating phosphate utilization to growth; (6) ecological aspects covering manifestations of phosphorus limitation, interspecific competition for phosphonutrients among microorganisms, and current views on phosphorus cycling and turnover in aquatic ecosystems. Although concentrating on the microalgae, the review often points out sounder conclusions drawn from bacteria and fungi, and includes specific macroalgae in considering certain subtopics where such algae were better investigated and provided a good basis for comparison with the microalgae.

540 citations

Journal ArticleDOI
TL;DR: After vacuolar perfusion of Chara internode cells, the cytoplasm remaining in situ can be reactivated by ATP to give full rates of streaming and movement is interpreted in terms of actin filaments in the stationary cortex interacting with a myosin-like protein which is able to link to endoplasmic organelles.
Abstract: After vacuolar perfusion of Chara internode cells, the cytoplasm remaining in situ can be reactivated by ATP to give full rates of streaming. Observations during both perfusion and reactivation indicated that the generation of the motive force was associated with fibres consisting of bundles of microfilaments. In the absence of ATP, the remaining endoplasmic organelles were immobilized along such fibres. When ATP was introduced, organelles moved along the fibres at speeds up to 50 mum S minus 1, but but were progressively released from contact to leave the fibres in a conspicuously clean state. Inorganic pyrophosphate freed the organelles from the fibres without supporting movements. Motility required millimolar Mg2nlevels, free Ca2nat 10 minus 7 M or less and was inhibited by high levels of Clminus and by pH's on either side of 7.0. The reactivated movements were rapidly and completely inhibited by 25mug ml minus 1 cytochalasin B. The results are interpreted in terms of actin filaments in the stationary cortex interacting with a myosin-like protein which is able to link to endoplasmic organelles. Movement results from an active shear type of mechanism.

238 citations

Journal ArticleDOI
TL;DR: The data strongly suggest that an electrogenic ion pump in the plasma membrane of Neurospora is fueled by ATP; comparison of the measured membrane potentials with the energy available from hydrolysis of ATP indicates that two ions could be pumped for each molecule of ATP split.
Abstract: Sudden respiratory blockade has been used to study rapid changes of the resting membrane potential, of intracellular adenosine 5′-triphosphate (ATP) levels, and of pyridine nucleotide reduction inNeurospora crassa. Membrane depolarization occurs with a first-order rate constant of 0.167 sec−1, following a lag period of about 4 sec, at 24°C (ambient temperature). This depolarization is several-fold too slow to be directly linked to electron transfer, as judged from the rate of pyridine nucleotide reduction, but has essentially the same rate constant as the decay of ATP. The latter process, however, shows no lag period after the respiratory inhibitor is introduced. Plots of membrane potential versus the intracellular ATP concentration yield saturation curves which are readily fitted by a Michaelis equation, to which is added a constant term representing the diffusion component of membrane potential. Parameters obtained from such fits indicate the maximal voltage which the pump can develop at high ATP levels to be 300 to 350 mV, with an apparentK 1/2 of 2.0mm. The data strongly suggest that an electrogenic ion pump in the plasma membrane ofNeurospora is fueled by ATP; comparison of the measured membrane potentials with the energy available from hydrolysis of ATP indicates that two ions could be pumped for each molecule of ATP split.

235 citations


Cites background from "The active transport of ions in pla..."

  • ...This argument alone is not compelling, however, since at least one other ion transport process presumed to reside in the plasma m e m b r a n e - chloride transport in the giant algae [22, 29, 30] - appears more closely tied to electron transfer (photoelectron transfer) than to phosphate bond energy....

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Journal ArticleDOI
01 Sep 1973
TL;DR: An attempt is made to borrow information from the physiology of bacteria, fungi, and higher plants where they augment observations on algae in an attempt to find new insights into the metabolic roles of nutrients and the mechanisms of their assimilation.
Abstract: Treatments of inorganic nutrition tend to become listings of poorly related facts and observations. As more information becomes available, this should give way to a drawing together of observations in an attempt to find new insights into the metabolic roles of nutrients and the mechanisms of their assimilation. In the present review, an attempt is made to do this, borrowing information from the physiology of bacteria, fungi, and higher plants where they augment observations on algae. In doing so, some erroneous suggestions are probable, but hopefully areas of needed research will be pointed out.

229 citations

References
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Journal ArticleDOI
08 Jul 1961-Nature
TL;DR: Coupling of Phosphorylation to Electron and Hydrogen Transfer by a Chemi-Osmotic type of Mechanism is described.
Abstract: Coupling of Phosphorylation to Electron and Hydrogen Transfer by a Chemi-Osmotic type of Mechanism

4,039 citations

Journal ArticleDOI
TL;DR: The end result of the coupling between the flows through the o/r and h/d pathways in oxidative phosphorylation in mitochondria is that, for the equivalent of each pair of electrons traversing the respiratory chain, up to 3 anhydro-bond equivalents may normally traverse the h/D pathway from adenosine diphosphate plus inorganic phosphate (ADP +Pi) to water.
Abstract: 50 years ago Peter Mitchell proposed the chemiosmotic hypothesis for which he was awarded the Nobel Prize for Chemistry in 1978. His comprehensive review on chemiosmotic coupling known as the first "Grey Book", has been reprinted here with permission, to offer an electronic record and easy access to this important contribution to the biochemical literature. This remarkable account of Peter Mitchell's ideas originally published in 1966 is a landmark and must-read publication for any scientist in the field of bioenergetics. As far as was possible, the wording and format of the original publication have been retained. Some changes were required for consistency with BBA formats though these do not affect scientific meaning. A scanned version of the original publication is also provided as a downloadable file in Supplementary Information and can be found online at doi:10.1016/j.bbabio.2011.09.018. See also Editorial in this issue by Peter R. Rich. Original title: CHEMIOSMOTIC COUPLING IN OXIDATIVE AND PHOTOSYNTHETIC PHOSPHORYLATION, by Peter Mitchell, Glynn Research Laboratories, Bodmin, Cornwall, England.

3,225 citations

Journal ArticleDOI
TL;DR: It is shown that for a free ion diffusing through a membrane the ratio between the flux in one direction and the simultaneous flux in the opposite direction is independent of the structure of the membrane.
Abstract: Summary. 1) It is shown that for a free ion diffusing through a membrane the ratio between the flux in one direction and the simultaneous flux in the opposite direction is independent of the structure of the membrane. This ratio , which can be evaluated through tracer experiments, is equal to the ratio between the electrochemical activities of the ion on the two sides of the membrane. 2) Deviations from the equation indicate that the ion does not diffuse in the free state only, but, in part at least, as a component of some other moving particle in the membrane. Complex formation for instance as a part of an active transport mechanism brings about deviations from the above equation. 3) The diffusion of iodide through the isolated surviving frog skin is studied by means of the radioactive I131. I- diffuses inwards faster than outwards under all conditions studied. Nevertheless, no active transport of I- need be postulated since the potential difference across the skin is somewhat higher than required to explain the difference in diffusion rate. 4) Both influx and outflux of I- show a negative correlation to the potential difference, so that high P. D. values are found only when the I- permeability is low.

677 citations

Book
01 Jan 1964

605 citations

Journal ArticleDOI
TL;DR: The hypothesis that membrane flow may be an important part of a type of active transport mechanism carrying particles, including ions, along, within, into, and out of cells is introduced.
Abstract: Dr. Palade has shown that in many cells the cell membrane is infolded extensively and that such folds may carry the cell membrane to positions deep in the cell. Moreover, he has shown that such deep folds often appear to lie close to isolated vesicles in the cytoplasm. Dr. Palade has pointed out that such vesicles are often arranged so as to suggest that they might have formed from the pinching off of a recessed tip of such a fold, or that they might represent vesicles destined to coalesce with such a recessed fold. Dr. Palade referred to the classical paper on pinocytosis by Lewis (8). Lewis showed cells in which the cell surface and adjacent cytoplasm were in a state of vigorous activity, with an orderly flow of granules and vesicles from one portion of a cell to another. Similar activity and orderly movements within cells have been demonstrated by Gey, Shapras, and Borysko (6), by Frederic and Ch~vremont (5), and by Blandau, De Marsh, and Ralph (1). Dr. Palade's pictures suggest that in such cells as macrophages, in which pinocytosis and orderly flow of cytoplasmic particles are evident, the cytoplasmic membranes of the endoplasmic reticulum, particularly those components representing membranes folded inwards from the outer cell border, might participate in or even mediate these activities. I would like to introduce the hypothesis that membrane flow may be an important part of a type of active transport mechanism carrying particles, including ions, along, within, into, and out of cells. If membrane is being formed or synthesized in one region, and is being broken down or enzymatically destroyed at another, it would be expected to flow from the membrane source to the membrane sink or site of breakdown. If the source is at the exposed cell surface, as at A and A' in Fig. 1, and the sink is deep in the cell as at B (Fig. 1), the membrane would flow from the surface to a position deep in the recess as indicated by the arrows. A membrane flow in the reverse direction would result from a source at the tip of the recess at B and a sink on the surface at A or A'. Membranes entirely within the cell or entirely on the exposed cell surface or extending through the cell as tunnels or slits could be envisioned as similarly motivated to flow from sources to appropriately placed sinks. The energy required for such kinesis would be provided by oxidative mechanisms in the cell. 99

429 citations