scholarly journals SODIUM EXCLUSION AND POTASSIUM RETENTION BY THE RED MARINE ALGA, PORPHYRA PERFORATA

1958 ◽  
Vol 41 (5) ◽  
pp. 901-911 ◽  
Author(s):  
Richard W. Eppley
Keyword(s):  
Concentration Gradient ◽  
Marine Alga ◽  
Metabolic Inhibitors ◽  
Reduced Sulfur Compounds ◽  
Concentration Gradients ◽  
Potassium Accumulation ◽  
Potassium Loss ◽  
Sodium Extrusion ◽  
Potassium Retention ◽  
Red Marine Alga

Cells of the red marine alga, Porphyra perforata, accumulate potassium and exclude sodium, chloride, and calcium. Various metabolic inhibitors including dinitrophenol, anoxia, and p-chloromercuribenzoate partially abolish the cells' ability to retain potassium and exclude sodium. Iodoacetate induces potassium loss only in the dark; reduced sulfur compounds offer protection against the effects of p-chloromercuribenzoate; dinitrophenol stimulates respiration at concentrations which cause potassium loss and sodium gain. Following exposure to anoxia potassium accumulation and sodium extrusion take place against concentration gradients. These movements are retarded by sodium cyanide, but are stimulated by light. Sodium entry, following long exposure to 0.6 M sucrose, occurs rapidly with the concentration gradient, while potassium entry against the concentration gradient takes place slowly, and is prevented by cyanide.

scholarly journals Potassium Accumulation and Sodium Efflux by Porphyra perforata Tissues in Lithium and Magnesium Sea Water

1959 ◽  
Vol 43 (1) ◽  
pp. 29-38 ◽  
Author(s):  
Richard W. Eppley
Keyword(s):  
Concentration Gradient ◽  
Marine Alga ◽  
Sea Water ◽  
Secondary Process ◽  
Na Transport ◽  
K Uptake ◽  
Potassium Accumulation ◽  
Sodium Efflux ◽  
Na Efflux ◽  
Red Marine Alga

Cells of Porphyra perforata, a red marine alga, accumulate K in the absence of concomitant Na or Li extrusion while immersed in Li- or Mg-sea waters lacking Na. This suggests that the coupling observed between K and Na transport is facultative. No evidence is obtained for net extrusion of Li. Na efflux, with the concentration gradient, is facilitated by K and is proportional to the cellular Na content. Either Na efflux does not involve an ion carrier or the number of Na sites is large. Because K accumulation has been observed in the absence of Na extrusion, but not vice versa, it seems that K uptake is the primary secretory event, with Na extrusion a secondary process dependent upon K accumulation.

scholarly journals POTASSIUM-DEPENDENT SODIUM EXTRUSION BY CELLS OF PORPHYRA PERFORATA, A RED MARINE ALGA

1958 ◽  
Vol 42 (2) ◽  
pp. 281-288 ◽  
Author(s):  
Richard W. Eppley
Keyword(s):  
Marine Alga ◽  
Sea Water ◽  
High Sodium ◽  
Low Concentrations ◽  
Carrier Mechanism ◽  
Low Potassium ◽  
Sodium Extrusion ◽  
Rubidium Accumulation ◽  
Red Marine Alga

Potassium-free artificial sea water causes a loss of cell potassium and a gain of cell sodium in Porphyra perforata, which is not attributable to an inhibition of respiration. On adding KCl or RbCl to such low potassium, high sodium tissues, net accumulation of potassium or rubidium takes place, accompanied by net extrusion of sodium. Rates of potassium or rubidium accumulation and sodium extrusion are proportional to the amount of KCl or RbCl added only at low concentrations. Saturation of rates is evident at KCl or RbCl concentrations above 20–30 mM, suggesting the role of an ion carrier mechanism of transport. Evidence for and against mutually dependent sodium extrusion and potassium or rubidium accumulation is discussed.

The energy requirement for sodium extrusion from a frog muscle

1954 ◽  
Vol 142 (908) ◽  
pp. 383-392 ◽  
Keyword(s):  
Oxygen Consumption ◽  
Energy Production ◽  
Energy Requirement ◽  
Metabolic Inhibitors ◽  
Sodium Efflux ◽  
External Potassium ◽  
Radioactive Sodium ◽  
Sodium Extrusion ◽  
Frog Sartorius ◽  
Made In

Parallel measurements have been made of the oxygen consumption and efflux of radioactive sodium in pairs of frog sartorius muscles. Calculation of the amount of secretory work necessary for an active extrusion of sodium at the observed rate showed that it would involve the utilization of about one-tenth of the energy available from resting metabolism.This figure may reasonably be regarded as a lower limit to the efficiency of the secretory mechanism. Some of the measurements were made in a potassium-free Ringer’s solution, and others with an external potassium concentration of 10mM. In the potassium-rich medium, both the sodium efflux and the oxygen consumption were increased, the proportion of the energy production required for sodium extrusion remaining roughly constant. The action of dinitrophenol and other metabolic inhibitors on the sodium efflux in sartorius muscles was examined, but there were no very obvious effects.

scholarly journals In vitro activities of kappa-carrageenan isolated from red marine alga Hypnea musciformis: Antimicrobial, anticancer and neuroprotective potential

2018 ◽  
Vol 112 ◽  
pp. 1248-1256 ◽  
Author(s):  
Ricardo Basto Souza ◽  
Annyta Fernandes Frota ◽  
Joana Silva ◽  
Celso Alves ◽  
Agnieszka Zofia Neugebauer ◽  
...  
Keyword(s):  
Marine Alga ◽  
Hypnea Musciformis ◽  
Kappa Carrageenan ◽  
Red Marine Alga

Experimental and Numerical Investigation of H2-Air Deflagration in the Presence of Concentration Gradients

2013 ◽  
Author(s):  
S. Kudriakov ◽  
E. Studer ◽  
M. Kuznetsov ◽  
J. Grune
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Hydrogen Concentration ◽  
Concentration Gradient ◽  
Large Scale ◽  
Gravity Concentration ◽  
Concentration Gradients ◽  
Flame Acceleration ◽  
Institute Of Technology ◽  
Karlsruhe Institute

A set of experiments performed at Karlsruhe Institute of Technology (KIT) in the framework of the LACOMECO European project is devoted to flame propagation in an obstructed large scale facility A3 (of 8 m height and 33 m3 volume) with initially vertical hydrogen concentration gradients. Almost linear positive and negative (relative to gravity) concentration gradients are created prior to ignition in the range from 4% to 13%, and the process of flame acceleration is investigated depending on hydrogen concentration gradient and ignition positions. In this paper we describe the A3 facility and analyse the experimental data obtained during the project. The results of numerical simulation performed using Europlexus code are presented together with the critical discussions and conclusions.

The Pursuit of Potent Anti-influenza Activity from the Antarctic Red Marine Alga Gigartina skottsbergii

2010 ◽  
pp. 1-12
Author(s):  
J. Alan Maschek ◽  
Cynthia J. Bucher ◽  
Alberto van Olphen ◽  
Charles D. Amsler ◽  
James B. McClintock ◽  
...  
Keyword(s):  
Marine Alga ◽  
Gigartina Skottsbergii ◽  
Influenza Activity ◽  
The Antarctic ◽  
Red Marine Alga

Antiherpes Virus Effect of the Red Marine Alga Polysiphonia denudata

2000 ◽  
Vol 55 (9-10) ◽  
pp. 830-835 ◽  
Author(s):  
Julia Serkedjieva
Keyword(s):  
Marine Alga ◽  
Water Extract ◽  
Antiviral Effect ◽  
Inhibitory Effect ◽  
Extracellular Virus ◽  
Black Sea Coast ◽  
Red Marine Alga ◽  
Replicative Cycle

Abstract The water extract from the red marine alga Polysiphonia denudata (Dillwyn) Kütz. from the Bulgarian Black Sea coast selectively inhibited the reproduction of herpes virus type 1 and type 2 in cell cultures (EC50 = 8.7 to 47.7 mg/ml) as shown by the reduction of virusinduced cytopathic effect and viral infectivity. The virus-inhibitory effect was dose-related, strain-specific and depended on virus inoculum. The inhibition affected adsorption as well as the intracellular stages of viral replication. The presence of the extract throughout the whole replicative cycle was necessary for the full expression of the antiviral effect. In higher concentrations (MIC90 = 6.5 mg/ml) the extract exhibited strong extracellular virus inactivating activity.

scholarly journals Agglutinin isolated from the red marine alga Hypnea cervicornis J. Agardh reduces inflammatory hypernociception: Involvement of nitric oxide

2010 ◽  
Vol 96 (4) ◽  
pp. 371-377 ◽  
Author(s):  
Jozi G. Figueiredo ◽  
Flavio S. Bitencourt ◽  
Thiago M. Cunha ◽  
Patrícia B. Luz ◽  
Kyria S. Nascimento ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Marine Alga ◽  
Red Marine Alga

Delesserine, a new metabolite of mixed biogenesis from the red marine alga Delesseria sanguinea (Lamouroux)

1982 ◽  
Vol 104 (16) ◽  
pp. 4497-4498 ◽  
Author(s):  
Jean Claude Yvin ◽  
Anne Marie Chevolot-Magueur ◽  
Lionel Chevolot ◽  
Jean Yves Lallemand ◽  
Pierre Potier ◽  
...  
Keyword(s):  
Marine Alga ◽  
Red Marine Alga

Ammonia diffusion through Nalophan™ bags

2013 ◽  
Vol 69 (3) ◽  
pp. 486-494 ◽  
Author(s):  
Selena Sironi ◽  
Lidia Eusebio ◽  
Licinia Dentoni ◽  
Laura Capelli ◽  
Renato Del Rosso
Keyword(s):  
Concentration Gradient ◽  
Diffusion Rate ◽  
Water Concentration ◽  
Ammonia Concentration ◽  
Polymeric Film ◽  
Concentration Gradients ◽  
Storage Times ◽  
Film Interface ◽  
Over Time

The aim of the work is to verify the diffusion rate of ammonia through the Nalophan™ film that constitutes the sampling bag, considering storage times ranging from 1 to 26 h. The ammonia decay over time was evaluated using gas-chromatography for the quantification of ammonia concentration inside the bag. The research assesses the roles of both of ammonia and water concentration gradients at the polymeric film interface on the diffusion process. The results show that both the ammonia concentration gradient and, in a less pronounced way, the water concentration gradient are the main ‘engines’ of ammonia diffusion. Double bags seem to represent a simple solution for preventing ammonia losses during storage. Another interesting result concerns the role of the bag surface on the ammonia diffusion rate: the higher the surface/volume (S/V) ratio, the higher the ammonia diffusion rate through the polymeric film.

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