Glutathione (GSH) is the most abundant cellular thiol antioxidant and it exhibits numerous and versatile functions. Disturbances in GSH homeostasis have been associated with liver diseases induced by drugs, alcohol, diet and environmental pollutants. Until recently, our laboratories and others have developed mouse models with genetic deficiencies in glutamate-cysteine ligase (GCL), the rate-limiting enzyme in the GSH biosynthetic pathway. This review focuses on regulation of GSH homeostasis and, specifically, recent studies that have utilized such GSH-deficient mouse models to investigate the role of GSH in liver disease processes. These studies have revealed a differential hepatic response to distinct profiles of hepatic cellular GSH concentration. In particular, mice engineered to not express the catalytic subunit of GCL in hepatocytes [Gclc(h/h) mice] experience almost complete loss of hepatic GSH (to 5% of normal) and develop spontaneous liver pathologies characteristic of various clinical stages of liver injury. In contrast, mice globally engineered to not express the modifier subunit of GCL [Gclm(−/−) mice] show a less severe hepatic GSH deficit (to ≈15% of normal) and exhibit overall protection against liver injuries induced by a variety of hepatic insults. Collectively, these transgenic mouse models provide interesting new insights regarding pathophysiological functions of GSH in the liver.
Fanconi anemia (FA) is a recessively inherited disease manifesting developmental abnormalities, bone marrow failure, and increased risk of malignancies. Whereas FA has been studied for nearly 90 years, only in the last 20 years have increasing numbers of genes been implicated in the pathogenesis associated with this genetic disease. To date, 19 genes have been identified that encode Fanconi anemia complementation group proteins, all of which are named or aliased, using the root symbol “FANC.” Fanconi anemia subtype (FANC) proteins function in a common DNA repair pathway called “the FA pathway,” which is essential for maintaining genomic integrity. The various FANC mutant proteins contribute to distinct steps associated with FA pathogenesis. Herein, we provide a review update of the 19 human FANC and their mouse orthologs, an evolutionary perspective on the FANC genes, and the functional significance of the FA DNA repair pathway in association with clinical disorders. This is an example of a set of genes––known to exist in vertebrates, invertebrates, plants, and yeast––that are grouped together on the basis of shared biochemical and physiological functions, rather than evolutionary phylogeny, and have been named on this basis by the HUGO Gene Nomenclature Committee (HGNC).
Different mutation operators have been proposed in evolutionary programming, but for each operator there are some types of optimization problems that cannot be solved efficiently. A mixed strategy, integrating several mutation operators into a single algorithm, can overcome this problem. Inspired by evolutionary game theory, this paper presents a mixed strategy evolutionary programming algorithm that employs the Gaussian, Cauchy, Lévy, and single-point mutation operators. The novel algorithm is tested on a set of 22 benchmark problems. The results show that the mixed strategy performs equally well or better than the best of the four pure strategies does, for all of the benchmark problems.
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