No abstract

Seasonal variations of biometric parameters as well as metal and protein concentrations were analyzed in the liver cytosol of indigenous European chub (Squalius cephalus L.). Fish sampling was carried out in the reproductive (spring) and non-reproductive period (autumn) in order to define parameters which are seasonally dependent. The specimens caught in the spring period had higher biometric (liver mass, condition and hepatosomatic indices) and some biochemical parameters (metallothionein (MT) and Mn) that are characteristic for the reproductive period. Contrary, Fe hepatic cytosolic concentrations were significantly lower in specimens from spring than in autumn period. Total cytosolic proteins, Cu and Cd concentrations were not seasonally dependent. Range of constitutive levels was determined for total cytosolic proteins (17.7 to 24.7 mg ml(-1)) from the whole set of data. Constitutive range of seasonally dependent parameters MT (207 to 337 microg ml(-1)) and Mn (0.11 to 0.19 microg ml(-1)) is based on the data from non-reproductive period. In order to avoid the interference of reproductive cycle on the level of selected biochemical parameters, it is recommended to perform chub sampling during non-reproductive period.

Dragun, Zrinka; Podrug, Marijana; Raspor, Biserka. The assessment of natural causes of metallothionein variability in the gills of European chub (Squalius cephalus L.). // Comparative Biochemistry and Physiology Part C - Toxicology and Pharmacology. 150 (2009) could be concluded that, under the conditions of low dissolved metal concentrations in the 28 river water (as reported for the Sava River), MTs seem to be more affected by different biotic 29 factors than by metal exposure. Therefore, MTs measured in this study were considered as the 30 constitutive gill MT levels of young European chub. The constitutive MT ranges were defined 31 separately for the season of lower metabolic rate (autumn: 1.31-2.00 mg g -1 ) and the season of 32 higher metabolic acitivity (spring: 2.15-2.95 mg g -1 ). 33 Dragun, Zrinka; Podrug, Marijana; Raspor, Biserka. The assessment of natural causes of metallothionein variability in the gills of European chub (Squalius cephalus L.). // Comparative Biochemistry and Physiology Part C - Toxicology and Pharmacology. 150 (2009) , 2; 209-217 2

1 2In the autumn 2005, the site-specific variability of cytosolic metal and protein concentrations 3 in the gills of the European chub from the Sava River could be mostly associated to the gill 4 mass variability. In the spring 2006, the correlations of metals and proteins with the gill mass 5 were mainly non significant, and their site-specific variability could be presumably associated 6 to the river water pollution. The spring cytosolic concentrations of Zn, Cu and Mn have not 7 differed significantly between the sites (median: 8.37-11.34 g mL -1 , 68.2-86.2 ng mL -1 , 55.9-8 68.6 ng mL -1 , respectively), while increased cytosolic Cd concentrations were obtained at 9Oborovo and Lukavec Posavski (median: 4.01 ng mL -1 ), the sites influenced by the pollution 10 sources from two major urban areas, compared to the remaining sampling sites (median: 1.93 11 ng mL -1 ). The cytosolic Fe concentrations were almost twice higher at Jasenovac (median: 12 11.98 g mL -1 ) compared to the concentrations at Sava-Zagreb (median: 6.72 g mL -1 ). The 13 labile Fe concentrations measured in the river water with passive samplers indicated that 14 cytosolic Fe concentrations in the spring possibly reflected the water-borne Fe-uptake. The 15 spring cytosolic protein concentrations decreased from upstream (Otok Samoborski: 27.25.6 16 mg mL -1 ) towards the downstream sites (Lukavec Posavski: 14.82.8 mg mL -1 ), possibly due 17 to the influence of organic pollution and water toxicity. The spring period seemed to be more 18 appropriate season for the assessment of the river water pollution, if the chub gills are used as 19 the target organ. 20 21