Kopenski enakonožci vrste Porcellio scaber so v naravnem okolju izpostavljeni številnim patogenom in parazitom, ki lahko pri gostitelju povzročijo poškodbe tkiv ter vplivajo na imunokompetenco in ...fitnes organizma. Bakterijska okužba povzroči aktivacijo mehanizmov prirojene imunosti, kot so fagocitoza, tvorba reaktivnih kisikovih in dušikovih zvrsti, aktivnost antioksidativnih encimov, nodulacija ter proces melanizacije. Molekularni vzorci patogenov oziroma mikrobov ter s patogenezo povezane poškodbe pri gostitelju sprožijo prepisovanje genov v celicah hemolimfe, tj. hemocitih, ki opravljajo pomembno funkcijo mediatorjev imunskega odgovora. V aktualni raziskavi smo preučevali spremembe v izražanju genov ob simptomatski bakterijski okužbi z Rhabochlamydia porcellionis ter jih primerjali z asimptomatskimi oziroma zdravimi P. scaber. Iz hemolimfe (hemocitov) asimptomatskih in simptomatskih živali smo izolirali celokupno RNA, jo prepisali v cDNA ter z metodo RT-qPCR določili relativno izražanje izbranih genov, povezanih z imunostjo (Toll4, Dscam, MyD88, Cat, MnSod, CypG, A2m, Atg5 in Nos). Ugotovili smo značilne spremembe v izražanju izbranih genov, kar kaže na njihovo vlogo v imunskem odgovoru P. scaber v primeru bakterijske okužbe, dodatno pa smo z biokemijskimi metodami dokazali povečano aktivnost encima alfa-2-makroglobulin ter mejno značilno povišanje encima katalaza. Na podlagi rezultatov lahko zaključimo, da preučevani geni predstavljajo molekularne označevalce za imunski odziv, ki jih je moč uporabiti v različnih okoljskih raziskavah.
Abstract A number of reports on potential toxicity of nanoparticles are available, but there is still a lack of knowledge concerning bioaccumulation. The aim of this work was to investigate how ...different sources of zinc, such as uncoated and unmodified ZnO nanoparticles, ZnCl2 in solution, and macropowder ZnO influence the bioaccumulation of this metal in the terrestrial isopod Porcellio scaber. After exposure to different sources of Zn in the diet, the amount of assimilated Zn in whole body, the efficiency of zinc assimilation, and bioaccumulation factors (BAFs) were assessed. The bioaccumulation potential of Zn was found to be the same regardless of Zn source. The amount of assimilated Zn and BAF were dose-dependent, and Zn assimilation efficiency was independent of exposure concentrations. The Zn assimilation capacity was found to be up to 16% of ingested Zn. It is known that as much as approximately 20% of Zn can be accreted from ZnO particles by dissolution. We conclude that bioaccumulation of Zn in isopods exposed to particulate ZnO depends most probably on Zn dissolution from ZnO particles and not on bioaccumulation of particulate ZnO.
A number of reports on potential toxicity of nanoparticles are available, but there is still a lack of knowledge concerning bioaccumulation. The aim of this work was to investigate how different ...sources of zinc, such as uncoated and unmodified ZnO nanoparticles, ZnCl
2 in solution, and macropowder ZnO influence the bioaccumulation of this metal in the terrestrial isopod
Porcellio scaber. After exposure to different sources of Zn in the diet, the amount of assimilated Zn in whole body, the efficiency of zinc assimilation, and bioaccumulation factors (BAFs) were assessed. The bioaccumulation potential of Zn was found to be the same regardless of Zn source. The amount of assimilated Zn and BAF were dose-dependent, and Zn assimilation efficiency was independent of exposure concentrations. The Zn assimilation capacity was found to be up to 16% of ingested Zn. It is known that as much as approximately 20% of Zn can be accreted from ZnO particles by dissolution. We conclude that bioaccumulation of Zn in isopods exposed to particulate ZnO depends most probably on Zn dissolution from ZnO particles and not on bioaccumulation of particulate ZnO.
The aim of this work was to investigate if the activities of catalase and glutathione S-transferase in a control population of terrestrial isopods (Porcellio scaber) are correlated with the ...physiological condition of the isopods. For this purpose, the activities of these enzymes were analysed in isopods from a stock population and in parallel, the physiological condition of the same specimens was assessed using a histological approach based on epithelial thickness and lipid droplets. We found a correlation between antioxidant enzymes and the physiological condition of the isopods. This implies that these enzymes could be used as predictive indicators of the physiological condition in a stock population before comprehensive toxicological studies are conducted and also in control group after the experiment. When a control group is found to be very heterogeneous in terms of physiological condition, the experiment should be repeated with a larger number of experimental animals. The findings of this study will contribute to more accurate experimental design of toxicity tests when using biomarkers. This should encourage other researchers to increase their effort to know the physiological state of their test organisms.
► Catalase (CAT) and glutathione S-transferase (GST) in Porcellio scaber are variable. ► We found their correlation to histological appearance of digestive gland. ► Therefore, physiological condition of isopods can be assessed based on CAT and GST. ► This is applicable prior to use of isopods in comprehensive toxicological studies. ► This will contribute to more accurate experimental design when using biomarkers.
The focused ion beam (FIB) was used to prepare cross sections of precisely selected regions of the digestive gland epithelium of a terrestrial isopod P. scaber (Isopoda, Crustacea) for scanning ...electron microscopy (SEM). The FIB / SEM system allows ad libitum selection of a region for gross morphologic to ultrastructural investigation, as the repetition of FIB/SEM operations is unrestricted. The milling parameters used in our work proved to be satisfactory to produce serial two‐dimensional (2‐D) cuts and/or three‐dimensional (3‐D) shapes on a submicrometer scale. A final, cleaning mill at lower ion currents was employed to minimize the milling artifacts. After cleaning, the milled surface was free of filament‐ and ridge‐like milling artifacts. No other effects of the cleaning mill were observed.
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