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Bio‐inspired and biodegradable quantum optics scenarios constitute a pathway toward environmentally friendly front‐end technologies. Such an inspiring perspective necessitates the replacement of classic gain materials with a biological counterpart like photoluminescent bacteria. It is easy to imagine that, in this case, a planar and cell‐viable substitute of classic bulk solid‐states resonators can be highly beneficial. In this paper a micro‐ and nano‐photonic structuration of both a standard and a functionalized version of a typical bacterial growth medium (Luria‐Bertani Agar – LBA) is successfully realized. Three structures belonging to the categories of photonic crystals are replicated, such as quasi‐crystals and meta‐surfaces, demonstrating how the proposed media can be used as templates for high‐end photonic applications. The optical quality of the replicated structures is confirmed by far‐field diffraction measurements. The structured growth media allow for a broad control of the surface wettability by accessing a so‐called Wenzel state, in which the original hydrophilicity of a material is increased due to the photonic structuration. Finally, the suitability of the nano‐structured LBA as a plasmonic platform is evidenced. The proposed micro‐and nano‐structured photonic growth media constitute the first, fundamental step toward quantum optical frameworks from biological media. [ABSTRACT FROM AUTHOR]

FLAD1, along with its FAD synthase (FADS, EC 2.7.7.2) product, is crucial for flavin homeostasis and, due to its role in the mitochondrial respiratory chain and nuclear epigenetics, is closely related to cellular metabolism. Therefore, it is not surprising that it could be correlated with cancer. To our knowledge, no previous study has investigated FLAD1 prognostic significance in pancreatic ductal adenocarcinoma (PDAC). Thus, in the present work, the FAD synthesis process was evaluated in two PDAC cell lines: (a) PANC‐1‐ and PANC‐1‐derived cancer stem cells (CSCs), presenting the R273H mutation in the oncosuppressor p53, and (b) MiaPaca2 and MiaPaca2‐derived CSCs, presenting the R248W mutation in p53. As a control, HPDE cells expressing wt‐p53 were used. FADS expression/activity increase was found with malignancy and even more with stemness. An increased FAD synthesis rate in cancer cell lines is presumably demanded by the increase in the FAD‐dependent lysine demethylase 1 protein amount as well as by the increased expression levels of the flavoprotein subunit of complex II of the mitochondrial respiratory chain, namely succinate dehydrogenase. With the aim of proposing FADS as a novel target for cancer therapy, the inhibitory effect of Chicago Sky Blue on FADS enzymatic activity was tested on the recombinant 6His‐hFADS2 (IC50 = 1.2 μm) and PANC‐1‐derived CSCs' lysate (IC50 = 2–10 μm). This molecule was found effective in inhibiting the growth of PANC‐1 and even more of its derived CSC line, thus assessing its role as a potential chemotherapeutic drug. [ABSTRACT FROM AUTHOR]

Mitochondrial Ca2+ ions are crucial regulators of bioenergetics and cell death pathways. Mitochondrial Ca2+ content and cytosolic Ca2+ homeostasis strictly depend on Ca2+ transporters. In recent decades, the major players responsible for mitochondrial Ca2+ uptake and release have been identified, except the mitochondrial Ca2+/H+ exchanger (CHE). Originally identified as the mitochondrial K+/H+ exchanger, LETM1 was also considered as a candidate for the mitochondrial CHE. Defining the mitochondrial interactome of LETM1, we identify TMBIM5/MICS1, the only mitochondrial member of the TMBIM family, and validate the physical interaction of TMBIM5 and LETM1. Cell‐based and cell‐free biochemical assays demonstrate the absence or greatly reduced Na+‐independent mitochondrial Ca2+ release in TMBIM5 knockout or pH‐sensing site mutants, respectively, and pH‐dependent Ca2+ transport by recombinant TMBIM5. Taken together, we demonstrate that TMBIM5, but not LETM1, is the long‐sought mitochondrial CHE, involved in setting and regulating the mitochondrial proton gradient. This finding provides the final piece of the puzzle of mitochondrial Ca2+ transporters and opens the door to exploring its importance in health and disease, and to developing drugs modulating Ca2+ exchange. Synopsis: TMBIM5 mediates mitochondrial Ca2+/H+ exchange and interacts with the K+/H+ exchanger LETM1 to maintain mitochondrial pH, Ca2+ and K+ homeostasis. The K+/H+ exchanger LETM1 was proposed to mediate mitochondrial Ca2+/H+ exchange.Transmembrane BAX Inhibitor Motif containing protein 5 (TMBIM5) interacts with LETM1 and maintains mitochondrial K+/H+ exchange.TMBIM5, but not LETM1, mediates pH‐dependent mitochondrial Ca2+ extrusion.TMBIM5 regulates cell metabolism by setting the mitochondrial proton gradient. [ABSTRACT FROM AUTHOR]

Recent studies elucidated how riboflavin transporters and FAD forming enzymes work in humans and create a coordinated flavin network ensuring the maintenance of cellular flavoproteome. Alteration of this network may be causative of severe metabolic disorders such as multiple acyl-CoA dehydrogenase deficiency (MADD) or Brown-Vialetto-van Laere syndrome. A crucial step in the maintenance of FAD homeostasis is riboflavin uptake by plasma and mitochondrial membranes. Therefore, studies on recently identified human plasma membrane riboflavin transporters are presented, together with those in which still unidentified mitochondrial riboflavin transporter(s) have been described. A main goal of future research is to fill the gaps still existing as for some transcriptional, functional and structural details of human FAD synthases (FADS) encoded by FLAD1 gene, a novel 'redox sensing' enzyme. In the frame of the hypothesis that FADS, acting as a 'FAD chaperone', could play a crucial role in the biogenesis of mitochondrial flavo-proteome, several basic functional aspects of flavin cofactor delivery to cognate apo-flavoenzyme are also briefly dealt with. The establishment of model organisms performing altered FAD homeostasis will improve the molecular description of human pathologies. The molecular and functional studies of transporters and enzymes herereported, provide guidelines for improving therapies which may have beneficial effects on the altered metabolism. [ABSTRACT FROM AUTHOR]

The expression of carnitine plasma membrane transporter OCTN2 was evaluated in virus and nonvirus-mediated cancer. Both OCTN2 mRNA and protein levels were reduced in keratinocytes retrotransduced with HPV16 E6 and E7 compared with the control. The OCTN2 expression was reduced also in keratinocytes retrotransduced with the sole HPV16 E6. A similar down-regulation of OCTN2 mRNA level was observed in a naturally HPV16-infected cancer cell line, CaSki, harbouring several copies of HPV16 whole genome. The mechanism of down-regulation is not related to p53 transcriptional activity because in SAOS (p53-null) cell line, the restoration of p53 expression did not rescue OCTN2 expression. The treatment of keratinocytes retrotransduced with HPV16 E6 and E7 with 5-aza-cytidine rescued the OCTN2 expression, indicating that the mechanism of down-regulation is linked to DNA methylation. Low levels of mRNA expression of OCTN2 were found also in several nonvirus-related epithelial cancer cell lines. The treatment of those cell lines with 5-aza-cytidine again rescued the expression of OCTN2 as well. These data demonstrate for the first time that the OCTN2 transporter is generally down-regulated in virus and nonvirus-mediated epithelial cancers, probably via methylation of its promoter region. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A soluble form of human FAD synthase (isoform 2; hFADS2) was produced and purified to homogeneity as a recombinant His-tagged protein. The enzyme binds 1 mole of the FAD product very tightly, although noncovalently. Complete release of FAD from the 'as isolated' protein requires extensive denaturation. A 75 : 25 mixture of apo/holoprotein could be prepared by treatment with mild chaotropes, allowing estimatation of the contribution made by bound FAD to the protein stability and evaluatation of whether structural rearrangements may be required for FAD release. Under turnover conditions, the enzyme catalyzes FAD assembly from ATP and FMN and, at a much lower rate, the pyrophosphorolytic hydrolysis of FAD. Several mechanistic features of both reactions were investigated in detail, along with their dependence on environmental conditions (pH, temperature, dependence on metals). Our data indicate that FAD release may represent the rate-limiting step of the whole catalytic cycle and that the process leading to FAD synthesis, and delivery to client apoproteins may be tightly controlled. [ABSTRACT FROM AUTHOR]