Cadmium has no known physiological function in the body; however, its adverse effects are associated with cancer and many types of organ system damage. Although much has been shown about Cd toxicity, the underlying mechanisms of its responses to the organism remain unclear. In this study, the role of Tor1, a catalytic subunit of the target of rapamycin complex 2 (TORC2), in Cd-mediated effects on cell proliferation, the antioxidant system, morphology, and ionome balance was investigated in the eukaryotic model organism Schizosaccharomyces pombe. Surprisingly, spectrophotometric and biochemical analyses revealed that the growth rate conditions and antioxidant defense mechanisms are considerably better in cells lacking the Tor1 signaling. The malondialdehyde (MDA) content of Tor1-deficient cells upon Cd treatment represents approximately half of the wild-type content. The microscopic determination of the cell morphological parameters indicates the role for Tor1 in cell shape maintenance. The ion content, determined by inductively coupled plasma optical emission spectroscopy (ICP-OES), showed that the Cd uptake potency was markedly lower in Tor1-depleted compared to wild-type cells. Conclusively, we show that the cadmium-mediated cell impairments in the fission yeast significantly depend on the Tor1 signaling. Additionally, the data presented here suggest the yet-undefined role of Tor1 in the transport of ions.
- MeSH
- homeostáza účinky léků MeSH
- ionty metabolismus MeSH
- kadmium aplikace a dávkování toxicita MeSH
- malondialdehyd metabolismus MeSH
- oxidační stres účinky léků MeSH
- proteinkinasy genetika metabolismus MeSH
- regulace genové exprese u hub MeSH
- Schizosaccharomyces pombe - proteiny genetika metabolismus MeSH
- Schizosaccharomyces cytologie účinky léků fyziologie MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- Publikační typ
- časopisecké články MeSH
Fission yeast 'cut' mutants show defects in temporal coordination of nuclear division with cytokinesis, resulting in aberrant mitosis and lethality. Among other causes, the 'cut' phenotype can be triggered by genetic or chemical perturbation of lipid metabolism, supposedly resulting in shortage of membrane phospholipids and insufficient nuclear envelope expansion during anaphase. Interestingly, penetrance of the 'cut' phenotype in mutants of the transcription factor cbf11 and acetyl-coenzyme A carboxylase cut6, both related to lipid metabolism, is highly dependent on growth media, although the specific nutrient(s) affecting 'cut' occurrence is not known. In this study, we set out to identify the growth media component(s) responsible for 'cut' phenotype suppression in Δcbf11 and cut6-621 cells. We show that mitotic defects occur rapidly in Δcbf11 cells upon shift from the minimal EMM medium ('cut' suppressing) to the complex YES medium ('cut' promoting). By growing cells in YES medium supplemented with individual EMM components, we identified ammonium chloride, an efficiently utilized nitrogen source, as a specific and potent suppressor of the 'cut' phenotype in both Δcbf11 and cut6-621. Furthermore, we found that ammonium chloride boosts lipid droplet formation in wild-type cells. Our findings suggest a possible involvement of nutrient-responsive signaling in 'cut' suppression.
- MeSH
- acetyl-CoA-karboxylasa genetika MeSH
- chlorid amonný chemie metabolismus farmakologie MeSH
- fenotyp MeSH
- kultivační média chemie MeSH
- lipidová tělíska účinky léků metabolismus MeSH
- metabolismus lipidů účinky léků genetika MeSH
- mitóza účinky léků genetika MeSH
- mutace MeSH
- penetrance MeSH
- Schizosaccharomyces pombe - proteiny genetika MeSH
- Schizosaccharomyces účinky léků genetika růst a vývoj metabolismus MeSH
- transkripční faktory genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The abc1(-)/coq8(-) gene deletion respiratory-deficient mutant NBp17 of fission yeast Schizosaccharomyces pombe displayed a phenotypic fermentation pattern with enhanced production of glycerol and acetate, and also possessed oxidative stress-sensitive phenotypes to H(2)O(2), menadione, tBuOOH, Cd(2+), and chromate in comparison with its parental respiratory-competent strain HNT. As a consequence of internal stress-inducing mutation, adaptation processes to restore the redox homeostasis of mutant NBp17 cells were detected in minimal glucose medium. Mutant NBp17 produced significantly increased amounts of O(2)•- and H(2)O(2) as a result of the decreased internal glutathione concentration and the only slightly increased glutathione reductase activity. The Cr(VI) reduction capacity and hence the •OH production ability were decreased. The mutant cells demonstrated increased specific activities of superoxide dismutases and glutathione reductase (but not catalase) to detoxify at least partially the overproduction of reactive oxygen species. All these features may be explained by the decreased redox capacity of the mutant cells. Most notably, mutant NBp17 hyperaccumulated yellow CdS.
- MeSH
- ABC transportéry genetika MeSH
- delece genu MeSH
- fenotyp MeSH
- glutathion metabolismus MeSH
- kadmium metabolismus MeSH
- mikrobiální testy citlivosti MeSH
- oxidace-redukce MeSH
- oxidancia farmakologie MeSH
- peroxidy metabolismus MeSH
- Schizosaccharomyces pombe - proteiny genetika MeSH
- Schizosaccharomyces účinky léků genetika metabolismus MeSH
- ubichinon genetika MeSH
- Publikační typ
- časopisecké články MeSH
Lytic enzymes from the hepatopancreas of Helix pomatia do not induce a uniform digestion of the cell wall of Schizosaccharomyces pombe over the entire cell surface. Perforations are formed in growth zones through which a protoplast can locally protrude. Conditions were found under which the frequency of formation of apical protoplast protuberances is higher than 90% cells with such protuberances can reverse to normally multiplying cells.
