Oxidation events and skin aging

Single cell gel electrophoresis assay: methodology and applications.

Human genomic DNA fragments containing catechol O-methyltransferase (COMT) sequences were isolated and the exon-intron structure analysed by sequencing, PCR and comparing to the human COMT cDNA sequences The gene contains six exons, of which exons 1 and 2 are non-coding MB-ATG and S-ATG codons, responsible for the initiation of translation of the membrane-bound (MB) and soluble (S) forms of the enzyme, are located in exon 3 Two distinct COMT-specific transcripts, 13 kb and 15 kb, were detected in various human tissues and cell lines Different quantities of the shorter COMT-specific mRNA in the tissues studied suggest a tissue-specific regulation of the COMT gene at transcriptional level Mapping of the 5′ ends of the COMT mRNAs showed that transcription initiates at multiple sites in two separate DNA regions, which are preceded by functional promoter sequences The proximal promoter (P1), located between the two translation initiation codons and extending approximately 200 bp upstream of the MB-ATG initiation codon, apparently gives rise to the 13-kb S-COMT mRNA (S-mRNA) The distal promoter (P2) is located in a DNA fragment in front of and partly overlapping the transcription-start region of the 15-kb transcript, suggesting that it controls the expression of this MB-mRNA Similarities between the rat and human COMT gene promoters are analyzed

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1432-1033.1994.tb19083.x

Genomic organization of the human catechol O-methyltransferase gene and its expression from two distinct promoters.

Progress in the chemistry of melanins and related metabolites

During the past decade, melanins and melanogenesis have attracted growing interest for a broad range of biomedical and technological applications. The burst of polydopamine-based multifunctional coatings in materials science is just one example, and the list may be expanded to include melanin thin films for organic electronics and bioelectronics, drug delivery systems, functional nanoparticles and biointerfaces, sunscreens, environmental remediation devices. Despite considerable advances, applied research on melanins and melanogenesis is still far from being mature. A closer intersectoral interaction between research centers is essential to raise the interests and increase the awareness of the biomedical, biomaterials science and hi-tech sectors of the manifold opportunities offered by pigment cells and related metabolic pathways. Starting from a survey of biological roles and functions, the present review aims at providing an interdisciplinary perspective of melanin pigments and related pathway with a view to showing how it is possible to translate current knowledge about physical and chemical properties and control mechanisms into new bioinspired solutions for biomedical, dermocosmetic, and technological applications.

/pdf/melanins-and-melanogenesis-from-pigment-cells-to-human-2ypbgsofos.pdf

Melanins and melanogenesis: from pigment cells to human health and technological applications.

Comet assay demonstrates a higher ultraviolet B sensitivity to DNA damage in dysplastic nevus cells than in common melanocytic nevus cells and foreskin melanocytes.

In the supernatant of melanoma cell culture SK mel 25 three indolic compounds-5-hydroxy-6-methoxyindole, 5-hydroxy-6-methoxyindolyl-2-carboxylic, and 6-hydroxy-5-methoxyindolyl-2-carboxylic acids-have been identified. The supernatants were extracted with ethyl acetate, derivatized, and analyzed by gas chromatography-mass spectrometry. The significance of this finding is discussed.

S Pavel

Papers

Comet assay demonstrates a higher ultraviolet B sensitivity to DNA damage in dysplastic nevus cells than in common melanocytic nevus cells and foreskin melanocytes.

Identification of three indolic compounds in a pigmented-melanoma cell-culture supernatant by gas chromatography-mass spectrometry

Dynamics of melanogenesis intermediates.

Identification of two Thormählen-positive compounds from melanotic urine by gas chromatography-mass spectrometry.

Eumelanin (precursor) metabolites as markers for pigmented malignant melanoma: a preliminary report.