The response of Saccharomyces cerevisiae to arsenic involves a large ensemble of genes, many of which are associated with glutathione-related metabolism. The role of the glutathione S-transferase (GST) product of the URE2 gene involved in resistance of S. cerevisiae to a broad range of heavy metals was investigated. Glutathione peroxidase activity, previously reported for the Ure2p protein, was unaffected in cell-free extracts of an ure2Δ mutant of S. cerevisiae. Glutathione levels in the ure2Δ mutant were lowered about threefold compared to the isogenic wild-type strain but, as in the wild-type strain, increased 2-2.5-fold upon addition of either arsenate (As(V)) or arsenite (As(III)). However, lack of URE2 specifically caused sensitivity to arsenite but not to arsenate. The protective role of URE2 against arsenite depended solely on the GST-encoding 3'-end portion of the gene. The nitrogen source used for growth was suggested to be an important determinant of arsenite toxicity, in keeping with non-enzymatic roles of the URE2 gene product in GATA-type regulation.

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Vitamin B12 is a water-soluble vitamin and an important micronutrient with critical role in DNA, protein, and lipid synthesis. It is responsible for one-carbon metabolism and cell division of nervous and hematopoietic cells. Among its various functions, the role as immunomodulator in cellular immunity, especially in elevating the number of CD8+ cells and NK cells, atracts scientiic interest. Many alternative anticancer and anti-inlammatory treatments involve the use of B12 together with other vitamins and nutrients, but still the scientiic information is too obscure and insuicient. Controversial data link tumorigenesis with either increased or decreased B12 blood levels in diferent types of cancer. Dietary intake and additional supplement with the vitamin do not protect against cancer risk, but the dominant opinion is to integrate B12 as part of rational and healthy nutrition to ensure proper function of the immune system. This chapter will review in brief the most important facts for vitamin B12 functions and properties. We will try also to present in concise way the human immune system and the exact role of B12 in immune activity with emphasis on the questionable participation of vitamin B12 in the process of carcinogenesis and its signiicance as anticancer immunotherapy.Keywords: vitamin B12, immunonutrition, immunomodulation, immunotherapy, tumorigenesis, cancer, inlammation IntroductionCancer is the inal outcome of uncontrolled overgrowth of normal cells. Cancer cells remain insensitive to antiproliferative signals and apoptosis. As a result, they replicate, proliferate, and invade ininitely and aggressively. Although the genetic events are thought to be the most important in the process of carcinogenesis, other factors can facilitate abnormal cell development. For many years, inlammation and anti-inlammatory response were widely associated with malignancy [1, 2] and recognized as major elements that trigger carcinogenesis.© 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Extended inlammation, especially in chronic infections, predisposes to cancer, but still the mechanism(s) involved is (are) not deinitely known. Usually all inlammatory processes are followed rapidly by anti-inlammatory defense response-excessive production of proinlammatory signals (mediators) and reactive oxygen and nitrogen species. The pro-inlammatory mediators (cytokines, chemokines, and eicosanoids) may stimulate proliferation of both untransformed and tumor cells [2]. The reactive oxygen and nitrogen species lead to oxidative stress and damage of macromolecules, especially DNA to increase the risk of genetic mutations and tumorigenesis [3].A continuously increasing number of microelements, vitamins, and mineral salts are reported to modulate the immune response and counter the inlamm...

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The aim of the present study was to assess the prevalence of hepatitis B surface antigen among pregnant women in Varna Region, Bulgaria. During the period 2009-2013, an average prevalence of 2.26% (95%CI 1.75, 2.91) was measured in a total number of 2,700 samples. Analysis demonstrated that rural residence and minority ethnic origin are important risk factors for hepatitis B infection among pregnant women with hazard ratios of 2.40 (95%CI 1.46, 3.94), and 2.43 (95%CI 1.46, 4.05) when compared with urban residence and ethnic majority origin, respectively. J. Med. Virol. 88:2012-2015, 2016. © 2016 Wiley Periodicals, Inc.

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Growth of Saccharomyces cerevisiae ure2Delta mutant strain was investigated in the presence of diverse oxidant compounds. The inability of the strain to grow on a medium supplemented with H(2)O(2) was confirmed and a relationship between diminishing levels of glutathione (GSH) and peroxide sensitivity was established. Data for the lack of significant effect of URE2 disruption on the cellular growth in the presence of paraquat and menadione were obtained. The possible role of Ure2p in acquiring sensitivity to oxidative stress by means of its regulatory role in the GATA signal transduction pathway was discussed. It was suggested that the susceptibility of ure2Delta mutant to the exogenous hydrogen peroxide can result from increased GSH degradation due to the deregulated localization of the gamma-glutamyl transpeptidase activating factors Gln3/Gat1. The important role of Ure2p in in vivo glutathione-mediated reactive oxygen species (ROS) scavenging was shown by measuring the activity of antioxidant enzymes glutathione peroxidase, superoxide dismutase (SOD) and catalase in an URE2 disrupted strain. A time-dependent increase in SOD and catalase activity was observed. More importantly, it was shown that the ure2 mutation could cause significant disturbance in cellular oxidant balance and increased ROS level.

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