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Öğe Characterization of long living yeast deletion mutants that lack mitochondrial metabolism genes DSS1, PPA2 and AFG3(Elsevier, 2019) Muid, K. A.; Kimyon, Onder; Reza, Shahadat Hasan; Karakaya, Huseyin Caglar; Koc, AhmetMolecular mechanisms of aging and longevity are still mostly unknown. Mitochondria play central roles in cellular metabolism and aging. In this study, we identified three deletion mutants of mitochondrial metabolism genes (ppa2 Delta, dss1 Delta, and afg3 Delta) that live longer than wild-type cells. These long-lived cells harbored significantly decreased amount of mitochondria] DNA (mtDNA) and reactive oxygen species (ROS). Compared to the serpentine nature of wild-type mitochondria, a different dynamics and distribution pattern of mitochondria were observed in the mutants. Both young and old long-lived cells produced relatively low but adequate levels of ATP for cellular activities. The status of the retrograde signaling was checked by expression of CIT2 gene and found activated in long-lived mutants. The mutant cells were also profiled for their gene expression patterns, and genes that were differentially regulated were determined. All long-lived cells comprised similar pleiotropic phenotype regarding mitochondrial dynamics and functions. Thus, this study suggests that DSS1, PPA2, and AFG3 genes modulate the lifespan by altering the mitochondrial morphology and functions.Öğe Characterization of the BETA1 gene, which might play a role in Beta vulgaris subsp maritima salt tolerance(Tubitak Scientific & Technological Research Council Turkey, 2017) Uysal, Ozge; Cakiroglu, Cigdem; Koc, Ahmet; Karakaya, Huseyin CaglarSalinity stress has a negative impact on plant growth, which affects homeostasis and productivity. The uptake of nonessential salt ions changes the osmotic balance of the cell and causes dehydration. Higher plants develop salt tolerance mechanisms to avoid dehydration. Sea beet (Beta vulgaris subsp. maritima) is a halophytic ancestor of cultivated sugar beet that displays salt stress tolerance. In this study, we screened a B. vulgaris subsp. maritima cDNA library in Saccharomyces cerevisiae strain Ab1 1c (ena1 triangle, nha 1/4 triangle, nhx1 triangle), which is deficient in sodium transport, to find sodium-detoxifying genes. We identified a cDNA construct, named BETA 1, providing salt tolerance to yeast cells. This gene had no previously described function. Intracellular sodium measurements demonstrated no significant differences between yeast cells expressing BETA1 or a sham vector, suggesting that sodium was not effluxed in BEZA1-expressing cells. Transcriptionally, BETA1 mRNA levels were induced immediately in leaves and later in the root system in response to the salt stress. Our results suggest that the BETA1 gene is part of the salt tolerance network in B. vulgaris subsp. maritima.Öğe Identification of novel arsenic resistance genes in yeast(Wiley, 2022) Isik, Esin; Balkan, Cigdem; Karl, Vivien; Karakaya, Huseyin Caglar; Hua, Sansan; Rauch, Sebastien; Tamas, Markus J.Arsenic is a toxic metalloid that affects human health by causing numerous diseases and by being used in the treatment of acute promyelocytic leukemia. Saccharomyces cerevisiae (budding yeast) has been extensively utilized to elucidate the molecular mechanisms underlying arsenic toxicity and resistance in eukaryotes. In this study, we applied a genomic DNA overexpression strategy to identify yeast genes that provide arsenic resistance in wild-type and arsenic-sensitive S. cerevisiae cells. In addition to known arsenic-related genes, our genetic screen revealed novel genes, including PHO86, VBA3, UGP1, and TUL1, whose overexpression conferred resistance. To gain insights into possible resistance mechanisms, we addressed the contribution of these genes to cell growth, intracellular arsenic, and protein aggregation during arsenate exposure. Overexpression of PHO86 resulted in higher cellular arsenic levels but no additional effect on protein aggregation, indicating that these cells efficiently protect their intracellular environment. VBA3 overexpression caused resistance despite higher intracellular arsenic and protein aggregation levels. Overexpression of UGP1 led to lower intracellular arsenic and protein aggregation levels while TUL1 overexpression had no impact on intracellular arsenic or protein aggregation levels. Thus, the identified genes appear to confer arsenic resistance through distinct mechanisms but the molecular details remain to be elucidated.Öğe The importance of boron in biological systems(Elsevier Gmbh, 2018) Uluisik, Irem; Karakaya, Huseyin Caglar; Koc, AhmetBoron is an essential element for plants and probably essential for human and animal health. Boron has a broad range of physiological effects on biological systems at low concentrations, whereas it is toxic to at high concentrations. Eventhough there are many studies on boron's biological effects and toxicity, more information is needed to understand the mechanisms of its action. The aim of the current work is to review boron's function, transport and toxicity in different biological systems.Öğe The importance of boron in biological systems (vol 45, pg 156, 2018)(Elsevier Gmbh, 2019) Uluisik, Irem; Karakaya, Huseyin Caglar; Koc, Ahmet[Abstract Not Available]
