Ascorbic acid supplementation suppresses cadmium-derived alterations in the fission yeast Schizosaccharomyces pombe

10.5219/1618 ◽  
2021 ◽  
Vol 15 ◽  
pp. 423-432
Author(s):  
Marek Kovár ◽  
Alica Navrátilová ◽  
Anna Trakovická ◽  
Miroslava Požgajová

Cadmium (Cd) a highly toxic environmental pollutant, that does not have any physiological function in the organism, represents a great concern for human health as it can be easily transported from its environmental sources to the food chain. Food, water, and air are the major sources of Cd exposure to the population. Cd-mediated impairments of the basic cellular properties largely depend on its ability to enhance the formation of reactive oxygen species (ROS) and thus triggers oxidative stress to the cell. With the use of fission yeast Schizosaccharomyces pombe (S. pombe) as the model organism, we have analyzed the impact of Cd on the cell growth intensity, as it represents the fundamental feature of all living organisms. Cells were incubated with different Cd concentrations for 3, 6, and 9 hours to investigate the effect of Cd on cell growth in a time and dose-dependent manner. Further possible Cd-derived alterations, as the peroxidation of membrane lipids or the functional impairment of the enzymatic antioxidant protection mechanisms, were investigated by determination of the MDA content and via catalase (CAT) activity detection. Moreover, ascorbic acid (AsA) pre-treatment was subjected to investigate the assumed positive effect of AsA against Cd toxicity. We show here on one hand that cells suffer under the influence of Cd, but on the other hand, they substantially profit from AsA supplementation. Because S. pombe is known to shares many molecular, and biochemical similarities with higher organisms, the effect of AsA in cadmium toxicity elimination might be expected to a similar extent also in other cell types.

2019 ◽  
Vol 11 (11) ◽  
pp. 956-966 ◽  
Author(s):  
Xiaojia Niu ◽  
Fan Zheng ◽  
Chuanhai Fu

Abstract Spatial regulation of microtubule catastrophe is important for controlling microtubule length and consequently contributes to the proper establishment of cell polarity and cell growth. The +TIP proteins including Tip1/CLIP-170, Klp5/Kinesin-8, and Alp14/XMAP215 reside at microtubule plus ends to regulate microtubule dynamics. In the fission yeast Schizosaccharomyces pombe, Tip1 and Alp14 serve as microtubule-stabilizing factors, while Klp5 functions oppositely as a catastrophe-promoting factor. Despite that Tip1 has been shown to play a key role in restricting microtubule catastrophe to the cell end, how Tip1 fulfills the role remains to be determined. Employing live-cell microscopy, we showed that the absence of Tip1 impairs the localization of both Klp5 and Alp14 at microtubule plus ends, but the absence of Klp5 prolongs the residence time of Tip1 at microtubule plus ends. We further revealed that Klp5 accumulates behind Tip1 at microtubule plus ends in a Tip1-dependent manner. In addition, artificially tethering Klp5 to microtubule plus ends promotes premature microtubule catastrophe, while tethering Alp14 to microtubule plus ends in the cells lacking Tip1 rescues the phenotype of short microtubules. These findings establish that Tip1 restricts microtubule catastrophe to the cell end likely by spatially restricting the microtubule catastrophe activity of Klp5 and stabilizing Alp14 at microtubule plus ends. Thus, the work demonstrates the orchestration of Tip1, Alp14, and Klp5 in ensuring microtubule catastrophe at the cell end.


2019 ◽  
Author(s):  
Aleksandar Vještica ◽  
Magdalena Marek ◽  
Pedro N’kosi ◽  
Laura Merlini ◽  
Gaowen Liu ◽  
...  

AbstractSchizosaccharomyces pombe is a widely used model organism that resembles higher eukaryotes in many aspects of cell physiology. Its popularity as an experimental system partially stems from the ease of genetic manipulations, where the innate homology-targeted repair is exploited to precisely edit the genome. While vectors to incorporate exogenous sequences into the chromosomes are available, most are poorly characterized. Here we show that commonly used fission yeast vectors, which upon integration produce repetitive genomic regions, yield unstable genomic loci. We overcome this problem by designing a new series of Stable Integration Vectors (SIV) that target four different prototrophy genes. SIV produce non-repetitive, stable genomic loci and integrate predominantly as single copy. Additionally, we develop a set of complementary auxotrophic alleles that preclude false-positive integration events. We expand the vector series to include antibiotic resistance markers, promoters, fluorescent tags and terminators, and build a highly modular toolbox to introduce heterologous sequences. Finally, as proof of concept, we generate a large set of ready-to-use, fluorescent probes to mark organelles and cellular processes with a wide range of applications in fission yeast research.


2019 ◽  
Vol 11 (11) ◽  
pp. 944-955 ◽  
Author(s):  
Wenyue Liu ◽  
Fan Zheng ◽  
Yucai Wang ◽  
Chuanhai Fu

Abstract Microtubules grow not only from the centrosome but also from various noncentrosomal microtubule-organizing centers (MTOCs), including the nuclear envelope (NE) and pre-existing microtubules. The evolutionarily conserved proteins Mto1/CDK5RAP2 and Alp14/TOG/XMAP215 have been shown to be involved in promoting microtubule nucleation. However, it has remained elusive as to how the microtubule nucleation promoting factors are specified to various noncentrosomal MTOCs, particularly the NE, and how these proteins coordinate to organize microtubule assembly. Here, we demonstrate that in the fission yeast Schizosaccharomyces pombe, efficient interphase microtubule growth from the NE requires Alp7/TACC, Alp14/TOG/XMAP215, and Mto1/CDK5RAP2. The absence of Alp7, Alp14, or Mto1 compromises microtubule regrowth on the NE in cells undergoing microtubule repolymerization. We further demonstrate that Alp7 and Mto1 interdependently localize to the NE in cells without microtubules and that Alp14 localizes to the NE in an Alp7 and Mto1-dependent manner. Tethering Mto1 to the NE in cells lacking Alp7 partially restores microtubule number and the efficiency of microtubule generation from the NE. Hence, our study delineates that Alp7, Alp14, and Mto1 work in concert to regulate interphase microtubule regrowth on the NE.


Toxins ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 503 ◽  
Author(s):  
Sabrina Adorisio ◽  
Alessandra Fierabracci ◽  
Isabella Muscari ◽  
Anna Liberati ◽  
Lorenza Cannarile ◽  
...  

Cladosporium species are endophytic fungi that grow on organic matter and are considered food contaminants. The anti-microbial and anti-tumor naphthoquinones fusarubin (FUS) and anhydrofusarubin (AFU) were isolated using column chromatography from a Cladosporium species residing inside Rauwolfia leaves. The impact of FUS and AFU on cell growth was assessed in acute myeloid leukemia (OCI-AML3) and other hematologic tumor cell lines (HL-60, U937, and Jurkat). Treatment with FUS or AFU reduced the number of OCI-AML3 cells as evaluated by a hemocytometer. Flow cytometry analyses showed that this effect was accompanied by diverse impairments in cell cycle progression. Specifically, FUS (20 or 10 μg/mL significantly decreased the percentage of cells in S phase and increased the percentage of cells in G2/M phase, whereas AFU increased the percentage of cells in G0/G1 phase (50 and 25 μg/mL) and decreased the percentage of cells in S (50 μg/mL) and G2/M (50 and 25 μg/mL) phases. Both substances significantly increased apoptosis at higher concentrations. The effects of FUS were more potent than those of AFU, with FUS up-regulating p21 expression in a p53-dependent manner, as detected by Western blot analyses, likely the consequence of decreased ERK phosphorylation and increased p38 expression (both of which increase p21 stability). FUS also decreased Akt phosphorylation and resulted in increased Fas ligand production and caspase-8/3-dependent apoptosis. These results suggest that FUS and AFU inhibit proliferation and increase apoptosis in cell lines derived from hematological cancers.


2002 ◽  
Vol 3 (3) ◽  
pp. 282-288 ◽  
Author(s):  
Valerie Wood ◽  
Jürg Bähler

Researchers are increasingly depending on various centralized resources to access the vast amount of information reported in the literature and generated by systematic sequencing and functional genomics projects. Biological databases have become everyday working tools for many researchers. This dependency goes both ways in that the databases require continuous feedback from the research community to maintain accurate, reliable, and upto- date information. The fission yeastSchizosaccharomyces pombehas recently been sequenced, setting the stage for the post-genome era of this popular model organism. Here, we provide an overview of relevant databases available, or being developed, together with a compilation of Internet resources containing useful information and tools for fission yeast.


2004 ◽  
Vol 48 (9) ◽  
pp. 3268-3271 ◽  
Author(s):  
M. Ernst Schweingruber

ABSTRACT The melaminophenyl arsenical melarsoprol is the main drug used against late-stage sleeping sickness caused by Trypanosoma brucei subspecies. Its active metabolite in the human body is melarsen oxide. Here, it is shown that this metabolite inhibits growth of the fission yeast Schizosaccharomyces pombe and that its toxicity can be abolished efficiently by thiamine (vitamin B1), thiamine analogues, and the pyrimidine moiety of the thiamine molecule. Uptake of melarsen oxide is mediated by a membrane protein (car1p), which is involved in the uptake of thiamine and its pyrimidine moiety. Melarsoprol is taken up by cells in a thiamine- and car1p-dependent manner but is not toxic to cells.


Author(s):  
Simon Emanuel Harnqvist ◽  
Cooper Alastair Grace ◽  
Daniel Charlton Jeffares

AbstractWhich variables determine the constraints on gene sequence evolution is one of the most central questions in molecular evolution. In the fission yeast Schizosaccharomyces pombe, an important model organism, the variables influencing the rate of sequence evolution have yet to be determined. Previous studies in other single celled organisms have generally found gene expression levels to be most significant, with numerous other variables such as gene length and functional importance identified as having a smaller impact. Using publicly available data, we used partial least squares regression, principal components regression, and partial correlations to determine the variables most strongly associated with sequence evolution constraints. We identify centrality in the protein–protein interactions network, amino acid composition, and cellular location as the most important determinants of sequence conservation. However, each factor only explains a small amount of variance, and there are numerous variables having a significant or heterogeneous influence. Our models explain more than half of the variance in dN, raising the possibility that future refined models could quantify the role of stochastics in evolutionary rate variation.


1995 ◽  
Vol 15 (9) ◽  
pp. 4964-4970 ◽  
Author(s):  
M Willer ◽  
L Hoffmann ◽  
U Styrkársdóttir ◽  
R Egel ◽  
J Davey ◽  
...  

The mat1 locus is a key regulator of both conjugation and meiosis in the fission yeast Schizosaccharomyces pombe. Two alternative DNA segments of this locus, mat1-P and mat1-M, specify the haploid cell types (Plus and Minus). Each segment includes two genes: mat1-P includes mat1-Pc and mat1-Pm, while mat1-M includes mat1-Mc and mat1-Mm. The mat1-Pc and mat1-Mc genes are responsible for establishing the pheromone communication system that mediates conjugation between P and M cells, while all four mat1 genes are required for meiosis in diploid P/M cells. Our understanding of the initiation of meiosis is based largely on indirect observations, and a more precise investigation of these events was required to define the interaction between the mat1 genes. Here we resolve this issue using synthetic pheromones and P/M strains with mutations in either mat1-Pc or mat1-Mc. Our results suggest a model in which the mat1 locus plays two roles in controlling meiosis. In the first instance, the mat1-Pc and mat1-Mc functions are required to produce the mating pheromones and receptors that allow the generation of a pheromone signal. This signal is required to induce the expression of mat1-Pm and mat1-Mm. This appears to be the major pheromone-dependent step in controlling meiosis since ectopic expression of these genes allows meiosis in the absence of mat1-Pc and mat1-Mc. The mat1-Pm and mat1-Mm products complete the initiation of meiosis by activating transcription of the mei3 gene.


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