Validation of oxidative stress responses in two populations of frogs from Western Ukraine.

Although amphibians are considered to be good bioindicators of environmental pollution, few data are available concerning their biochemical parameters in natural populations. We investigated seasonal (spring, summer, autumn) and spatial (wetlands in rural and urban areas) fluctuations of oxidative stress biomarkers in the liver of frog Rana ridibunda in Western Ukraine. The Centroid grouping analysis demonstrated that despite the fluctuations of separate indices, frogs from an urban site in summer and autumn are differed widely from those at the same site in spring and frogs from the rural site in all three seasons, joined in common set.

Autometallographic tracing of Hg-S quantum dots in frogs exposed to inorganic mercury.

The histochemical distribution of mercury in the kidneys and gut of frogs (Rana ridibunda) exposed to inorganic mercury was analyzed with autometallography (AMG). It was found that most mercury in the kidneys accumulated in the proximal convoluted tubules as Hg-S nanocrystal, while control animals were totally void of AMG grains. In the gut the highest concentration of mercury was observed in the large intestine.

Comparison of metal bioavailability in frogs from urban and rural sites of Western Ukraine.

The seasonal and spatial fluctuations of heavy metals in the liver of the frog Rana ridibunda from a river in Western Ukraine were investigated. Liver weight was seen to increase from spring to summer/autumn, most probably as a result of accumulation of metabolites, especially fat and glycogen. The concentrations of the metals found in the liver of the frog was in the order: Fe>Cu approximately Zn>Mn>Cd.

Liver histopathologic alterations in the frog Rana ridibunda from a small river of Northern Greece.

The various histopathologic alterations detected in the liver of the frog Rana ridibunda from a small river of Northern Greece were investigated. In the livers of the frogs collected from this river, there was an increase in the area occupied by melanomacrophages as well as an increase in their color intensity. Mild karyomegaly and polyploidy, together with solitary and focal accumulation of infiltrates (neutrophils and lymphocytes), was evident.

Heavy metal accumulation and metallothionein concentration in the frog Rana ridibunda after exposure to chromium or a mixture of chromium and cadmium.

The accumulation of two heavy metals (chromium (Cr) and cadmium (Cd)) in the liver, kidney and gut of Rana ridibunda exposed to Cr or to a mixture of Cr and Cd was investigated. The concentration of metallothioneins (MTs) in the same tissues was also studied. Both metals accumulated mainly in the kidney.

Effects of exposure to a mixture of cadmium and chromium on detoxification enzyme (GST, P450-MO) activities in the frog Rana ridibunda.

The effect of two heavy metals, namely chromium and cadmium, on GST and P450-MO activities in the liver, kidney and gut of the frog Rana ridibunda, and the use of these detoxification enzyme systems as possible markers of heavy metal contamination of rivers in Northern Greece was investigated. In control animals, the highest P450-MO activity was observed in the liver and the lowest activity in the gut. As regards GST, the liver and kidneys showed the highest activity.

Hepatotoxic and nephrotoxic effects of cadmium in the frog Rana ridibunda.

Histological and histochemical alterations in the liver and kidneys of the frog Rana ridibunda, which was exposed to 200 ppm aqueous solutions of cadmium for 4, 10 and 30 days, respectively were investigated. In both the liver and kidneys, essential changes appeared after 10 days' exposure, the maximum changes being apparent after 30 days of exposure. In the liver, what was very characteristic was an increase in the area occupied by Kupffer cells, with the area in the animals exposed to cadmium for 30 days being the largest observed.

Autometallographic tracing of mercury in frog liver.

The distribution of mercury in the liver of the frog Rana ridibunda with the autometallographic method was investigated. The mercury specific autometallographic (HgS/SeAMG) technique is a sensitive histochemical approach for tracing mercury in tissues from mercury-exposed organisms. Mercury accumulates in vivo as mercury sulphur/mercury selenium nanocrystals that can be silver-enhanced.

Nephrotoxic effects of lead nitrate in Rana ridibunda.

The impact of lead (Pb) on kidney histopathology of the frog Rana ridibunda was investigated. Female frogs were exposed for 4, 10 and 30 days to 14 ppm lead (as lead nitrate). All the lead concentrations and many histological changes were time dependent.

Copper kinetics and hepatic metallothionein levels in the frog Rana ridibunda, after exposure to CuCl2.

Adult female frogs Rana ridibunda were exposed to 50 and 100 ppm of Cu (as CuCl2) dissolved in water for 5, 15 and 30 days. We measured the Cu content in the liver, kidneys, ventral skin, and large intestine. Hepatic metallothionein (MT) was also measured and we identified by elution the type of proteins bound to copper.

Impact of cadmium on liver pigmentary system of the frog Rana ridibunda.

The liver pigmentary system of the frog Rana ridibunda was investigated after exposure to CdCl2. There was a time-dependent alteration in the area occupied by pigment cells. Most pigment was melanin, but lipofuscin and ferritin were also detected, being similarly increased with time.

Analysis of monoamines, adenosine and GABA in tissues of the land snail Helix lucorum and lizard Agama stellio stellio during hibernation.

The aim of the present study was to determine the levels of monoamines, GABA and adenosine in the brain, heart and haemolymph of the land snail Helix lucorum and in the brain, heart and blood of lizard Agama stellio stellio during long-term hibernation. We measured levels of the monoamines serotonin (5-HT) and its main metabolite 5-hydroxyindole-3-acetic acid (5-HIAA), dopamine (DA) and its metabolites dihydroxyphenylacetic acid (DOPAC) and homovanilic acid (HVA), norepinephrine (NE) and epinephrine (E). The most abundant amines detected in the brain and heart of active H.

Exposure of Rana ridibunda to lead II. Impact of lead on various parameters of liver metabolism of the frog Rana ridibunda.

There are no data at present on the impact of lead (Pb) on amphibian metabolism, although declines of amphibian populations due to man-made changes in the environment have been recorded in recent years. We studied the impact of Pb on the liver metabolism of the frog Rana ridibunda by measuring the hepatic levels of glycogen, lactate, total fat, protein and glucose. Liver is one of the primary target organs of Pb bioaccumulation.

Exposure of Rana ridibunda to lead I. Study of lead accumulation in various tissues and hepatic delta-aminolevulinic acid dehydratase activity.

There are few data at present on the impact of lead (Pb) on amphibians, although declines in amphibian populations due to man-made changes in the environment have been recorded in recent years. The impact of Pb in adult frogs, Rana ridibunda, was therefore examined. Animals were exposed to 14 mg l(-1) (ppm) aqueous Pb [as Pb(NO3)2] for 4, 10 and 30 days.

Cadmium accumulation in liver and kidneys and hepatic metallothionein and glutathione levels in Rana ridibunda, after exposure to CdCl2.

Adult female Rana ridibunda were exposed to 200 ppm (mg/l) of cadmium (Cd as CdCl2) dissolved in water for 4, 10, and 30 days. The 96-h LC50 value for Cd was determined to 534 ppm. The concentration of Cd in the liver and kidneys and the effect of Cd on the concentrations of hepatic metallothionein (Mts) and glutathione (GSH), were estimated.

Reproductive and lipid cycles in the male frog Rana ridibunda in northern Greece.

1. Reproductive and lipid cycles in the male frog Rana ridibunda were studied. 2.

Activity metabolism of the lizard Agama stellio stellio.

Oxygen consumption and lactate production above resting levels, and selected body temperatures, were measured in the lizard Agama stellio. Active and resting VO2 have low Q10 (1.7, 2.