Combined Effect of Dietary Cadmium and Benzo(a)pyrene on Metallothionein Induction and Apoptosis in the Liver and Kidneys of Bank Voles

Bank voles free living in a contaminated environment have been shown to be more sensitive to cadmium (Cd) toxicity than the rodents exposed to Cd under laboratory conditions. The objective of this study was to find out whether benzo(a)pyrene (BaP), a common environmental co-contaminant, increases Cd toxicity through inhibition of metallothionein (MT) synthesis—a low molecular weight protein that is considered to be primary intracellular component of the protective mechanism. For 6 weeks, the female bank voles were provided with diet containing Cd [less than 0.1 μg/g (control) and 60 μg/g dry wt.] and BaP (0, 5, and 10 μg/g dry wt.) alone or in combination. At the end of exposure period, apoptosis and analyses of MT, Cd, and zinc (Zn) in the liver and kidneys were carried out. Dietary BaP 5 μg/g did not affect but BaP 10 μg/g potentiated rather than inhibited induction of hepatic and renal MT by Cd, and diminished Cd-induced apoptosis in both organs. The hepatic and renal Zn followed a pattern similar to that of MT, attaining the highest level in the Cd + BaP 10-μg/g group. These data indicate that dietary BaP attenuates rather than exacerbates Cd toxicity in bank voles, probably by potentiating MT synthesis and increasing Zn concentration in the liver and kidneys

Ecotypes of Bacillus cereus sensu lato

Zdigitalizowano i udostępniono w ramach projektu pn. Rozbudowa otwartych zasobów naukowych Repozytorium Uniwersytetu w Białymstoku – kontynuacja, dofinansowanego z programu „Społeczna odpowiedzialność nauki” Ministra Edukacji i Nauki na podstawie umowy BIBL/SP/0040/2023/01.Bacillus cereus sensu lato is a group of bacteria common in the environment, which have an important impact on the activity of humans. Their taxonomy is still in doubt, mainly because of their properties enecoded by plasmid-borne genes that may potentially undergo horizontal gene transfer. Here we present genetic and phenotypic data that support the idea of a bacterial group (named B. cereus sensu lato) instead of several independent taxa. We conclude that B. cereus sensu lato is composed of distinct, but closely related ecotypes.This publication was financed by the Ministry of Science and Higher Education as a part of subsidies for maintaining the research potential granted to the Faculty of Biology and Chemistry at the University of Bialystok.M. Bartoszewicz: [email protected]. Bartoszewicz - Department of Microbiology, Institute of Biology, University of BialystokU. Czyżewska - Department of Cytobiochemistry, Institute of Biology, University of BialystokM. Siemieniuk - Department of Cytobiochemistry, Institute of Biology, University of BialystokS. Maciak - Department of evolutionary and physiological ecology, Institute of Biology, University of BialystokBartoszewicz, M. Święcicka, I., Buczek, J. (2006) Cereulidyna i enterotoksyny Bacillus cereus sensu lato. Medycyna Weterynaryjna, 62: 28-31.Bartoszewicz, M., Bideshi, D.K., Kraszewska, A. Modzelewska, E., Swiecicka, I. (2009) Natural isolates of Bacillus thuringiensis display genetic and psychrotrophic properties characteristic of Bacillus weihenstephanensis. Journal of Applied Microbiology, 106: 1967-1975.Bartoszewicz, M., Czyżewska, U. (2017a) Spores and vegetative cells of phenotypically and genetically diverse Bacillus cereus sensu lato are common bacteria in fresh water of northeastern Poland. Canadian Journal of Microbiology, 63: 939-950.Bartoszewicz, M., Czyżewska, U. (2017b) Taksonomia, wirulencja i cykle życiowe Bacillus cereus sensu lato. Postępy Mikrobiologii, 56: 440-450.Bartoszewicz, M., Marjańska, P.S. (2017) Milk-originated Bacillus cereus sensu lato strains harbouring Bacillus anthracis-like plasmids are genetically and phenotypically diverse. Food Microbiology, 67: 23-30.Ehling-Schulz, M., Vukov, N., Schulz, A., Shaheen, R., Andersson, M., Märtlbauer, E., Scherer, S. (2005) Identification and partial characterization of the nonribosomal peptide synthetase gene responsible for cereulide production in emetic Bacillus cereus. Applied and Environmental Microbiology, 71: 105-113.Jensen, G.B., Hansen, B.M., Eilenberg, J., Mahillon, J. (2003) The hidden lifestyles of Bacillus cereus and relatives. Environmental Microbiology, 5: 631-640.Kaminska, P.S., Yernazarova, A., Murawska, E., Swiecicki, J., Fiedoruk, K., Bideshi, D.K., Swiecicka, I. (2014) Comparative analysis of quantitative reverse transcription real-time PCR and commercial enzyme imunoassays for detection of enterotoxigenic Bacillus thuringiensis isolates. FEMS Microbiology Letters, 357: 34-39.Kroteń, M.A., Bartoszewicz, M., Święcicka, I. (2010) Cereulide and valinomycin, two important natural dodecadepsipeptides with ionophoretic activities. Polish Journal of Microbiology, 59: 3-10.Lechner, S., Mayr, R., Francis, K.P., Prufß, B.M., Kaplan, T., Wießner-Gunkel, E. Steward, G.S.A.B., Scherer, S. (1998) Bacillus weihenstephanensis sp. nov. is a new psychrotolerant species of the Bacillus cereus group. International Journal of Systematic Bacteriology, 48: 1373-1382.Małek, W., Wdowiak-Wróbel, S., Kalita, M., Święcicka, I. (2005) W poszukiwaniu koncepcji gatunku bakteryjnego. Postępy Mikrobiologii, 44: 323-328.Melnick, R.L., Testen, A.L., Poleatewich, A.M., Backman, P.A., Bailey, B.A. (2012) Detection and expression of enterotoxin genes in endophytic strains of Bacillus cereus. Letters in Applied Microbiology, 54: 468-474.Raymond, B., Bonsall, M.B. (2013) Cooperation and the evolutionary ecology of bacterial virulence: the Bacillus cereus group as a novel study system. Bioessays, 35: 706-716.Reiter, L., Kolsto, A-B., Piehler, A.P. (2011) Reference genes for quantitative, reverse-transcription PCR in Bacillus cereus group strains throughout the bacterial life cycle. Journal of Microbiological Methods, 86: 210-217.Swiecicka, I., Van der Auwera, G.A., Mahillon, J. (2006) Hemolytic and nonhemolytic enterotoxin genes are broadly distributed among Bacillus thuringiensis isolated from wild mammals. Microbial Ecology, 52: 544-551.11512

Supplementary Material for: Nucleolar Dominance and Repression of 45S Ribosomal RNA Genes in Hybrids between Xenopus borealis and X. muelleri (2n = 36)

<p>Nucleolar dominance is a dramatic disruption in the formation of nucleoli and the expression of ribosomal RNA (rRNA) genes, characteristic of some plant and animal hybrids. Here, we report that F₁ hybrids produced from reciprocal crosses between 2 sister species of <i>Xenopus</i> clawed frogs, <i>X. muelleri</i> and <i>X. borealis</i>, undergo nucleolar dominance somewhat distinct from a pattern previously reported in hybrids between phylogenetically more distant <i>Xenopus</i> species. Patterns of nucleolar development, 45S rRNA expression, and gene copy inheritance were investigated using a combination of immunostaining, pyrosequencing, droplet digital PCR, flow cytometry, and epigenetic inhibition. In <i>X. muelleri</i> × <i>X. borealis</i> hybrids, typically only 1 nucleolus is formed, and 45S rRNA genes are predominantly expressed from 1 progenitor's alleles, <i>X. muelleri</i>, regardless of the cross-direction. These changes are accompanied by an extensive (∼80%) loss of rRNA gene copies in the hybrids relative to their parents, with the transcriptionally underdominant variant <i>(X. borealis)</i> being preferentially lost. Chemical treatment of hybrid larvae with a histone deacetylase inhibitor resulted in a partial derepression of the underdominant variant. Together, these observations shed light on the genetic and epigenetic basis of nucleolar dominance as an underappreciated manifestation of genetic conflicts within a hybrid genome.</p

Gas sensors based on nanostructures of semiconductors ZnO and TiO2

The paper presents a resistance structures with sensor layers based on nanostructures elaborated on the base of TiO2 and ZnO. The structures were tested concerning their sensitivities to the effects of nitrogen dioxide in the atmosphere of synthetic air. The TiO2 and ZnO nanostructures played the role of sensor layers. Investigations have proved that the elaborated resistance structures with TiO2 and ZnO layers are sensitive to the presence of NO2 in the atmosphere of synthetic air. The resistance of the structure amounted to about 20 in the case of ZnO structures and to about 200 in the case of TiO2 structures. The investigations confirmed that resistance structures with ZnO and TiO2, exposed to the effect of nitrogen dioxide in the atmosphere of synthetic air changes their resistances relatively fast. This indicates that such structures might be practically applied in sensors of nitrogen dioxide ensuring a short time of response