Saccharomyces cerevisiae transcriptionally regulates the expression of the plasma membrane high affinity iron transport system in response to iron need. This transport system is comprised of the products of the FET3 and FTR1 genes. We show that Transition metals are essential for life, yet transition metals in high concentrations can be toxic. Both eukaryotes and prokaryotes tightly regulate the concentration of free intracellular metals by either regulating metal uptake or sequestration.

Citrus spp. are among the most widespread plants cultivated worldwide and every year millions of tons of fruit, juices, or processed compounds are produced and consumed, representing one of the main sources of nutrients in human diet. Among these, the flavonoids play a key role in providing a wide range of health beneficial effects. Apigenin, diosmetin, luteolin, acacetin, chrysoeriol, and their respective glycosides, that occur in concentrations up to 60 mg/L, are the most common flavones found in Citrus fruits and juices. The unique characteristics of their basic skeleton and the nature and position of the substituents have attracted and stimulated vigorous investigations as a consequence of an enormous biological potential, that manifests itself as (among other properties) antioxidant, anti-inflammatory, antiviral, antimicrobial, and anticancer activities. This review analyzes the biochemical, pharmacological, and biological properties of Citrus flavones, emphasizing their occurrence in Citrus spp. fruits and juices, on their bioavailability, and their ability to modulate signal cascades and key metabolic enzymes both in vitro and in vivo. Electronic databases including PubMed, Scopus, Web of Science, and SciFinder were used to investigate recent published articles on Citrus spp. in terms of components and bioactivity potentials.

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Evidence has been accumulated showing that inflammatory and cell death pathways are altered both in brain and periphery during Parkinson disease (PD). Neuronal loss in PD is associated with chronic neuroinflammation characterized by microglia activation through the release of reactive oxygen radicals, cytokines, and Prostaglandin E2. The release of these inflammatory mediators in addition to deprivation in growth factors and increase of calcium and dopamine seem implicated in triggering apoptosis. The interaction of leucine-rich repeat kinase and Fas- Associated protein with Death Domain has been implicated in the switching-on of the extrinsic apoptotic pathway via caspase-8 activation, while deficiency in PTEN induced putative kinase 1 has been shown to cause Ca2+ accumulation in mitochondria, increased generation of reactive oxygen species and intrinsic cell death. Autophagy/mitophagy appears to be impaired in the brain during PD; this impairment could be related to defective degradation of mutant α-synuclein and consequent apoptotic cell death. Regarding the peripheral blood, reduced amounts of dopamine, reduced levels of immunoreactivity for tyrosine hydroxylase and dopamine active transporter, and alterations of dopamine receptor expression have been detected in mononuclear cells from PD patients. In addition, mononuclear cells from PD patients show mitochondrial, ubiquitin-proteasome system dysfunction and up-regulation of α-synuclein gene, associated to high expression of the Fas molecule, activation of caspase-3 and -9 and proneness to apoptosis. These and other observations reported in this mini-review suggest that a better understanding of molecular dysfunctions in inflammatory and cell death/autophagy pathways, both in the brain and peripheral blood, could provide useful targets for future investigation on drug-discovery and biomarker identification in PD.

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The structural determinants required for ferroxidase activity by the yeast multicopper oxidase Fet3 have been partially clarified by site-directed mutagenesis based on homology modeling. Glu-185 and Tyr-354 were substituted with Ala and Phe, respectively. Fet3 E185A retained ca. 5% residual ferroxidase catalytic efficiency, and almost 40% oxidase efficiency. On the other hand, Fet3 Y354F exhibited 50% residual efficiency as a ferroxidase and more than 70% as an oxidase. These results provide new insights in the mechanism of iron binding and oxidation by Fet3, establishing the essential role of Glu-185 and Tyr-354, and allowing to dissect ferroxidase from non-iron oxidase activity.

This study aimed at investigating the genetic diversity of a panel of Candida africana strains recovered from vaginal samples in different countries. All fungal strains were heterozygous at the mating-type-like locus and belonged to the genotype A of Candida albicans. Moreover, all examined C. africana strains lack N-acetylglucosamine assimilation and sequence analysis of the HXK1 gene showed a distinctive polymorphism that impair the utilization of this amino sugar in this yeast. Multi-locus sequencing of seven housekeeping genes revealed a substantial genetic homogeneity among the strains, except for the CaMPIb, SYA1 and VPS13 loci which contributed significantly to the classification of our set of C. africana strains into six existing diploid sequence types. Amplified fragment length polymorphism fingerprint analysis yielded greater genotypic heterogeneity among the C. africana strains. Overall the data reported here show that in C. africana genetic diversity occurs and the existence of this intriguing group of C. albicans strains with specific phenotypes associated could be useful for future comparative studies in order to better understand the genetics and evolution of this important human pathogen.

BackgroundIn vertebrates, there is an intimate relationship between copper and iron homeostasis. Copper deficiency, which leads to a defect in ceruloplasmin enzymatic activity, has a strong effect on iron homeostasis resulting in cellular iron retention. Much is known about the mechanisms underlying cellular iron retention under “normal” conditions, however, less is known about the effect of copper deficiency during inflammation.ResultsWe show that copper deficiency and the inflammatory cytokine interleukin-6 have different effects on the expression of proteins involved in iron and copper metabolism such as the soluble and glycosylphosphtidylinositol anchored forms of ceruloplasmin, hepcidin, ferroportin1, transferrin receptor1, divalent metal transporter1 and H-ferritin subunit. We demonstrate, using the human HepG2 cell line, that in addition to ceruloplasmin isoforms, copper deficiency affects other proteins, some posttranslationally and some at the transcriptional level. The addition of interleukin-6, moreover, has different effects on expression of ferroportin1 and ceruloplasmin, in which ferroportin1 is decreased while ceruloplasmin is increased. These effects are stronger when a copper chelating agent and IL-6 are used simultaneously.ConclusionsThese results suggest that copper chelation has effects not only on ceruloplasmin but also on other proteins involved in iron metabolism, sometimes at the mRNA level and, in inflammatory conditions, the functions of ferroportin and ceruloplasmin may be independent.