DNA damage in a liver tissue of metal exposed Clethrionomys glareolus.

It is widely known that some toxic agents may act on DNA strand resulting in its damages. One of the possible impairments is formation of abasic sites in DNA. The aim of this study was to indicate a presence of these DNA sites in the liver tissue of bank voles inhabiting the vicinity of zinc/lead smelters. Samples that were used originated from animals collected from unpolluted (Niepolomice, Telesnica Oszwarowa, Mikolajki) and polluted (Miasteczko Slaskie, Katowice, Olkusz) populations. They significantly differed in terms of tissue lead concentrations in the kidney and liver. The means of detected AP sites per 105 bp ranged between 3.39 (Telesnica Oszwarowa) to 5.13 (Miasteczko Slaskie). Statistical analysis (ANOVA) showed no difference in terms of number of the AP sites between single populations. However, t-test showed significant difference between the unpolluted and polluted populations. Factorial ANOVA indicated that sex is not a factor influencing the number of AP sites. The analyses revealed statistically significant relationships between the number of AP sites and Cu concentrations in the liver, and also Pb and Cd concentrations in the kidney.

Variation of Metallothionein I and II Gene Expression in the Bank Vole (Clethrionomys glareolus) Under Environmental Zinc and Cadmium Exposure.

The main idea of the study was to assess how environmental metal pollution activates defence responses at transcription levels in the tissues of bank voles (Clethrionomys glareolus). For this purpose, the metallothioneine (MT) genes expression (a well known biomarker of exposure and response to various metals) was measured. The real-time PCR method was used for relative quantification of metallothionein I and metallothionein II expressions in the livers, kidneys and testes of bank voles from six populations exposed to different contaminants, mainly zinc, cadmium and iron. The assessment of Zn, Cu and Fe concentrations in the tissues allowed to study the MTs gene expression responses to these metals. ANOVA analysis showed differences between populations in terms of metal concentration in tissues, livers and kidneys. Student T test showed significant differences in metal concentration between unpolluted and polluted sites only for the liver tissue: significantly lower Zn levels and significantly higher Fe levels in the unpolluted sites. Kruskal-Wallis test performed on C T data shows differences in the gene expressions between populations for both MT genes for liver and testes. In the liver metallothionein I gene expression was upregulated in populations considered as more polluted (up to 7.5 higher expression in Miasteczko Slaskie comparing to Mikolajki). Expression of metallothionein II revealed a similar pattern. In kidneys, differences in expression of both MT genes were not that evident. In testes, MT upregulation in polluted sites was noted for metallothionein II. For metallothionein however, we found downregulation in populations from more contaminated sites. The expressions of both MTs were positively influenced by cadmium in kidney (concentration data from the previous study) and zinc and copper in liver, while cadmium had effects only on the liver MT II gene expression. Positive relationship was obtained for lead and metallothionein II expression in the liver.

A highly divergent Puumala virus lineage in southern Poland.

Puumala virus (PUUV) represents one of the most important hantaviruses in Central Europe. Phylogenetic analyses of PUUV strains indicate a strong genetic structuring of this hantavirus. Recently, PUUV sequences were identified in the natural reservoir, the bank vole (Myodes glareolus), collected in the northern part of Poland. The objective of this study was to evaluate the presence of PUUV in bank voles from southern Poland. A total of 72 bank voles were trapped in 2009 at six sites in this part of Poland. RT-PCR and IgG-ELISA analyses detected three PUUV positive voles at one trapping site. The PUUV-infected animals were identified by cytochrome b gene analysis to belong to the Carpathian and Eastern evolutionary lineages of bank vole. The novel PUUV S, M and L segment nucleotide sequences showed the closest similarity to sequences of the Russian PUUV lineage from Latvia, but were highly divergent to those previously found in northern Poland, Slovakia and Austria. In conclusion, the detection of a highly divergent PUUV lineage in southern Poland indicates the necessity of further bank vole monitoring in this region allowing rational public health measures to prevent human infections.

No ALAD Polymorphism in Bank Vole Populations from Unpolluted and Lead-Zinc Polluted Areas in Poland.

Although a variety of biomarkers has been developed to assess the adverse effect of lead on human and animal populations, studies show that the most important factor conditioning the response may be the genetic make-up of an individual. ALAD (delta aminolevulinic acid dehydratase) gene polymorphism found in human populations results in the existence of two alleles: ALAD1 and ALAD2. The difference between them is the result of one nucleotide change (G177C, rs1800435) which implicates different enzyme affinity for lead ions. As a result, carriers of these alleles respond differently to lead exposure in terms of tissue lead content, as well as neurobehavioral response. The aim of our study was to determine if such a phenomenon is present in wild animal populations. Two hypotheses were tested: (i) does the same ALAD polymorphism occur in lead exposed rodent species and is the frequency of different alleles similar to that of humans, (ii) if polymorphism exists, is the tissue lead content higher in individuals having ALAD2 alleles. We used bank voles (Myodes glareolus) inhabiting different lead contaminated sites for this purpose. The results obtained show no polymorphism in the bank vole populations that were studied. Contrary to the results obtained for humans, our study shows that all animals were found to have the C nucleotide. In human populations this nucleotide determines the ALAD2 allele and is much less frequent.

Genetic variation in bank vole populations in natural and metal-contaminated areas.

The effects of isolation and heavy-metal pollution on genetic diversity in Myodes (=Clethrionomys) glareolus populations were studied. Isolation and pollution are considered to have important effects on biodiversity. Animals were collected from ten populations in isolated (island), mainland, and metal-polluted areas. Three populations were in areas near zinc and lead smelters; four were on islands in the relatively unpolluted Mazurian Lake District and in the Bieszczady Mountains; and three were in clean-mainland areas in the Mazurian Lake District, the Niepolomice Forest, and the Bieszczady Mountains. Cadmium and lead concentrations in liver and kidney were measured to assess the animals' exposure to metals. The metal concentrations were greater in animals from areas classed as polluted than in animals from the clean-mainland areas and islands. The genetic diversity of each population was analyzed using eight microsatellite markers. The results confirmed that isolation adversely affects genetic diversity in M. glareolus populations (giving low heterozygosity and poor allelic richness), but the effect of metal exposure on genetic diversity was not strong. Of the samples from polluted areas, only the Katowice population, which is exposed to high levels of metal pollution and is also isolated because of human activity, showed genetic variation parameters that were similar to those for the island populations. Nei's genetic distances indicated that the island populations were genetically distant from each other and from the other populations, and there were noticeable inbreeding effects that would have been caused by the isolation of these populations.

First molecular evidence for Puumala hantavirus in Poland.

Puumala virus (PUUV) causes mild to moderate cases of haemorrhagic fever with renal syndrome (HFRS), and is responsible for the majority of hantavirus infections of humans in Fennoscandia, Central and Western Europe. Although there are relatively many PUUV sequences available from different European countries, little is known about the presence of this virus in Poland. During population studies in 2009 a total of 45 bank voles were trapped at three sites in north-eastern Poland, namely islands on Dejguny and Dobskie Lakes and in a forest near Mikolajki. S and M segment-specific RT-PCR assays detected PUUV RNA in three animals from the Mikolajki site. The obtained partial S and M segment sequences demonstrated the highest similarity to the corresponding segments of a PUUV strain from Latvia. Analysis of chest cavity fluid samples by IgG ELISA using a yeast-expressed PUUV nucleocapsid protein resulted in the detection of two seropositive samples, both being also RT-PCR positive. Interestingly, at the trapping site in Mikolajki PUUV-positive bank voles belong to the Carpathian and Eastern genetic lineages within this species. In conclusion, we herein present the first molecular evidence for PUUV in the rodent reservoir from Poland.