Search results

1

Electrophysiological effect of ruthenium red and pH on the skin of the frog, Rana esculenta L.

100%

Kosik-Bogacka D. I., Tyrakowski T.

Folia Biologica

|

2001

|

vol. 49

|

issue 3-4

273-277

EN

Amphibian skin is a sensitive interface between the organism and the environment. Metal ions from the external environment, some of them being trace elements, act on the amphibian skin. It had been shown that stimulation of tactile receptors affected Na+ transport in the frog skin and changed the potential difference, therefore the aim of this project was to study the effect of ruthenium complex, known as ruthenium red (RR), on the ion transport in this organ in vitro under control conditions, after mechanical stimulation and also in the presence of the Na+ transport inhibitor-amiloride. Three different concentrations of RR (0.12, 1.2, and 12.0 mM) in two different pH values (6.4 and 7.4) were studied in vitro in the Ussing apparatus. The measured electrophysiological parameters were the transepithelial electrical potential difference (PD) and the changes in PD after mechanical stimulation (dPD). The gentle mechanical stimulus was a jet of bath fluid from a peristaltic pump directed on the mucosal surface of isolated frog skin. After mechanical stimulation, transient hyperpolarization invariably occurred (dPD = 1.5_0.2 mV). In the presence of RR the hyperpolarization was smaller and this diminution was concentration dependent: 0.5_0.1 mV for 1.2 mM of RR and 0.1_0.1 mV for 1.2 mM of RR. At pH 6.4 the reactions of the skins on the mechanical and chemical stimuli were smaller, in the presence of amiloride disappearing completely, but after the washing away of amiloride from the experimental organ in pH 6.4 the action of RR was stimulatory. The natural defensive reactions of frog skin related to the ion transport and electrical potential difference are affected or disappear in the presence of ruthenium complex.

2

Seasonal and long-term succession of phytoplankton in shallow coastal water of the Southern Baltic Sea

88%

Wasmund N., Heerkloss R.

Oceanological Studies

|

1993

|

issue 64/3

203-213

3

The geochemical profile of bottom sediments in the Domiaza (Oder river estuary, northwest Poland)

51%

Piotrowski S., Laba-Mydlowska E.

Oceanological and Hydrobiological Studies

|

2003

|

issue 4

79-115

EN

The Domiaza is a fragment of the Oder river estuary situated north of Szczecin. This area is exposed to complex hydrological processes and strong anthropogenic pressure. Key physical and chemical parameters of the Domiaza sediments (fraction < 2mm), e.g., dry residue (Ds), ignition loss (Iz), CaCO3 and organic carbon content, show high coefficients of variation (over 60%). Similar variation is typical of the heavy metal concentrations (Cu, Zn, Pb, Co, Cd and Hg) and the organic carbon content in the fraction smaller than 0.20 mm. The spatial distribution of the examined parameters in the Domiaza sediments results from the dynamics of this environment, especially the heavy watercraft traffic and the continuous dredging of the Szczecin-Swinoujscie water lane. Concentrations of Cd, Cu, Zn, Pb and Co found in the Domiaza sediments are higher than those found in the geochemical background of Poland, while concentrations of mercury are comparable. Moreover, the concentrations of Cu, Zn, Pb and Cd found in the Domiaza sediments are higher than the average concentrations of these metals in adjacent areas (Oder River, Dabie Lake, Szczecin Lagoon), but the concentrations of Hg and Co are comparable or lower depending on the area of reference. A survey of heavy metals concentrations conducted in 1999 detected higher than average concentrations of Cu, Zn, Pb, and particularly Co (twice) and Hg (over thirty times), and lower concentrations of Cd in comparison with the average levels of 1996. The reason for these differences was the selective inflow of heavy metals to the Domiaza area after the disastrous flood of 1997.

Refine search results

1 Folia Biologica

1 Oceanological Studies

1 Oceanological and Hydrobiological Studies

1 2003

1 2001

1 1993

1 Heerkloss R.

1 Kosik-Bogacka D. I.

1 Laba-Mydlowska E.

1 Piotrowski S.

1 Tyrakowski T.

1 Wasmund N.

Electrophysiological effect of ruthenium red and pH on the skin of the frog, Rana esculenta L.

Seasonal and long-term succession of phytoplankton in shallow coastal water of the Southern Baltic Sea

The geochemical profile of bottom sediments in the Domiaza (Oder river estuary, northwest Poland)