Examination of very long hair (length > 2.4 m) using a large range of evaluation methods including physical, chemical, biochemical and microscopic techniques has enabled to attain a detailed understanding of natural ageing of human hair keratin fibres. Scrutinizing hair that has undergone little or no oxidative aggression--because of the absence of action of chemical agents such as bleaching or dyeing--from the root to the tip shows the deterioration process, which gradually takes place from the outside to the inside of the hair shaft: first, a progressive abrasion of the cuticle, whilst the cortex structure remains unaltered, is evidenced along a length of roughly 1 m onwards together with constant shine, hydrophobicity and friction characteristics. Further along the fibre, a significant damage to cuticle scales occurs, which correlates well with ceramides and 18-Methyl Eicosanoic Acid (18-MEA) decline, and progressive decrease in keratin-associated protein content. Most physical descriptors of mechanical and optical properties decay significantly. This detailed description of natural ageing of human hair fibres by a fine analysis of hair components and physical parameters in relationship with cosmetic characteristics provides a time-dependent 'damage scale' of human hair, which may help in designing new targeted hair care formulations.

The secretion of amylase and cellulase in Gryllus bimaculatus is determined by increased food intake, whereby shortly after molting food consumption increases. About half of the standing amylase concentration (activity) in the endothelial cells can be secreted within 30 min. The peak of amylase and cellulase secretion that occurs in the photophase is related to the feeding peak in the previous scotophase. The secretion of chitinase on the other hand is primarily controlled by the molting cycle. Only amylase secretion was affected by calcium in the incubation medium, suggesting an apocrine release mechanism. Refeeding experiments (after 5 days without food) suggest that the release of amylase in response to a nutrient in the lumen (glucose) is not due to simple stimulation of exocytosis, but rather a stimulation of synthesis.

Human skin is exposed to a number of harmful agents of which the ultraviolet (UV) component of solar radiation is most important. UV-induced damages include direct DNA lesions as well as oxidative damage in DNA, proteins and lipids caused by reactive oxygen species (ROS). Being the main site of ROS generation in the cell, mitochondria are particularly affected by photostress. The resulting mitochondrial dysfunction may have negative effects on many essential cellular processes. To counteract these effects, coenzyme Q10 (CoQ10 ) is used as a potent therapeutic in a number of diseases. We analyzed the mitochondrial respiration profile, the mitochondrial membrane potential and cellular ATP level in skin fibroblasts after irradiation. We observed an accelerated regeneration of cellular ATP level, a decrease in mitochondrial dysfunction as well as a preservation of the mitochondrial membrane potential after irradiation in human skin fibroblasts by treatment with CoQ10 . We conclude that the faster regeneration of the ATP level was achieved by a preservation of mitochondrial function by the addition of CoQ10 and that the protective effect of CoQ10 is primarily mediated via its antioxidative function. We suggest also that it might be further dependent on a stimulation of DNA repair enzymes by CoQ10 .

Plectonem a, Arylsulfatase. Thiosulfate R eductase, Substrate Induction, Cyanobacteria Arylsulfatase activity of the cyanobacterium P lectonem a 73110 is detected during growth on p-nitrophenyl sulfate as only sulfur source. A 60-fold purification of the soluble arylsulfatase yields a protein with an pH-optim um around 10 and K m data for p-nitrophenyl sulfate of 9.5 × 10" 5 and for nitrocatechol sulfate of 3.4 × 10-5. The enzym atic activity is not effected by the cations Mg2-, M n2+, K 2+ or Na + used as chloride salts. The anions SO32- and SO42-did not inhibit this activity, how ever EDTA , thiols and triton X -100 decreased this activity to about 25% w here­ as SDS inhibited com pletely. Sulfate limitation is necessary for the developm ent of arylsulfatase activity in the presence of its substrate p-nitrophenyl sulfate. This arylsulfatase activity is partly bound to m embranes.