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Far‐UVC radiation sources of wavelengths 222 nm and 233 nm represent an interesting potential alternative for the antiseptic treatment of the skin due to their high skin compatibility. Nevertheless, no studies on far‐UVC‐induced DNA damage in different skin types have been published to date, which this study aims for. After irradiating the skin with far‐UVC of the wavelengths 222 and 233 nm as well as broadband UVB, the tissue was screened for cyclobutane pyrimidine dimer‐positive (CPD+) cells using immunohistochemistry. The epidermal DNA damage was lower in dark skin types than in fair skin types after irradiation at 233 nm. Contrary to this, irradiation at 222 nm caused no skin type‐dependent differences, which can be attributed to the decreased penetration depth of radiation. UVB showed the relatively strongest differences between light and dark skin types when using a suberythemal dose of 3 mJ/cm2. As melanin is known for its photoprotective effect, we evaluated the ratio of melanin content in the stratum basale and stratum granulosum in samples of different skin types using two‐photon excited fluorescence lifetime imaging (TPE‐FLIM) finding a higher ratio up to skin type IV–V. As far‐UVC is known to penetrate only into the upper layers of the viable skin, the aforementioned melanin ratio could explain the less pronounced differences between skin types after irradiation with far‐UVC compared to UVB. [ABSTRACT FROM AUTHOR]

Honokiol is one of the natural extracts of Magnolia officinalis. It is a small molecule, lipophilic compound with extensive biological effects. It has been used in the treatment of multisystem diseases, including digestive diseases, endocrine diseases, nervous system diseases, and various tumors. This paper reviews the biological effects of honokiol on the treatment of skin diseases in recent years, including anti‐microbial, anti‐oxidant, anti‐inflammatory, anti‐tumor, anti‐fibrosis, anti‐allergy, photo‐protection, and immunomodulation. Most current researches are focused on the effects of anti‐melanoma and photo‐protection. Therefore, we summarized the specific mechanisms about these two effects. On the other side of treating skin diseases, the advantages of topical drugs cannot be replaced. As a small molecule fat‐soluble compound, honokiol is suitable for external use. We reviewed the advantages and disadvantages of the topical mixed cream and various improved methods. These improvements include physical and chemical penetration enhancers, drug carriers, and chemical derivatives. In conclusion, honokiol has a wide range of effects, and its topical preparation provides a safe and effective way for treating skin diseases. [ABSTRACT FROM AUTHOR]

Ultraviolet radiation (UVR) is recognized as a driving force for phenotypic divergence. Here, we aim at assessing the ability of zooplankton to induce UVR tolerance and disentangle the relative importance of local adaptations behind the expression of such tolerance. Two populations of Daphnia pulex, derived from environments strongly differing in UVR conditions, were exposed to UVR for 70 d to induce production of photo-protective compounds and changes in behavioral responses. We expected greater tolerance to UVR in individuals from the high-UVR (H-U) environment as well as a refuge demand inversely related to the level of pigmentation. However, the complementarity between physiological and behavioral strategies was only observed on animals from the Low-UVR environment (L-U). L-U animals developed photo-protective compounds and decreased their refuge demand when re-exposed to UVR, that is, tolerated more UVR, compared to their control siblings. Conversely, UVR-exposed individuals from the H-U environment even having developed higher levels of photo-protective compounds increased their refuge demand staying deeper in the water column compared to the control animals, likely expressing an evolutionary memory to seek refuge in deeper waters irrespective of the UVR level. Stronger changes were observed in the H-U population compared to the L-U population; thus, our results suggest that although changes in tolerance after UVR exposure were evident for both populations, the strength of the inductions was more related to local adaptation independently of the rearing environment, showing that UVR tolerance is dependent on the evolutionary history of each population. [ABSTRACT FROM AUTHOR]

Objectives These were two-fold: (i) to assess the possible changes in some facial signs induced in a 6-month period by the periodical shift from winter to summer in Caucasian women and (ii) to appraise the preventive effects of a strong photo-protective product. Methods The facial signs of two cohorts of French women ( N= 40 and 42), of comparable ages were graded between winter to summer. One group was left unprotected whereas the other daily applied a strong photo-protective product for 6 months. Facial signs (structural and pigmentation-related) were graded in blind by a panel of 12 experts from photographs taken under standard conditions. A global and focused analysis of the skin colour or dark spots, when present, was carried out through spectro-radiometry under diffuse and standardized visible light, using the L*, a*, b* referential system. Results The unprotected group showed significant changes in summer as compared to winter on 10 facial signs (two-third of the studied signs) that presented an increased severity, of variable respective amplitude. Five signs among the 10 were particularly and significantly affected by the seasonal transition, of an amplitude above the precision of the grading scale. Three of these five signs concerned structural elements (wrinkles), the two others being related to vascular disorders (redness). These season-induced alterations appear efficiently reduced in the photo-protected group. The colour of the facial skin then appears more homogeneous, less red, less dull, all criteria being quantified by the L*, a*, b* referential system. The comparison with a previous work carried out on Chinese women, through a similar protocol, shows that the photo-protective product brings, in Caucasian women, a more important effect upon structural and vascular features than upon pigmentation disorders, inversely to the results previously observed in Chinese women. Conclusion The alterations in some facial signs occurring in a 6-month period between winter and summer are confirmed in Caucasian women, mostly related to structural (wrinkles) and vascular elements. Such changes appear alleviated or prevented by daily applications of a strong sun photo-protective product. [ABSTRACT FROM AUTHOR]

Objectives These were two-fold: (i) to record through standardized pictures, the possible changes in 31 facial signs induced, in a 6-month period, by the periodical shift from winter to summer in a group of 43 Chinese women and (ii) to appraise the preventive effects of a strong photo-protective product, daily applied to the faces of an additional group ( N = 40) of women of same age-range and presenting same severities of facial signs in winter. Methods Facial signs (structural and pigmentation-related) were scored in blind by a panel of 12 experts from photographs taken under standard conditions. Scorings were performed under specific scales as established by a previously published referential Skin Aging Atlas, Volume 2, Asian Type. Results A significant seasonal impact was found for more than 60% of facial signs, that is presenting a higher severity in summer in the unprotected group. Some changes are of a low or subtle extent, whereas some others show significant amplitudes. The latter comprise eight signs, among the 31, that became, far above scoring threshold, indeed affected during this 6-month period. The observed changes in six of these eight signs, in majority related to pigmentation, appeared efficiently alleviated in the photo-protected group. Conclusion The shift from winter to summer exposure is confirmed in altering some facial pigmented signs among Chinese women. Such changes appear much alleviated by a daily strong photo-protective regimen. [ABSTRACT FROM AUTHOR]

We demonstrated a direct correlation between melanogenic and catalase activities on in vitro and ex vivo models. Here, we investigated whether the stimulation of Melanocortin-1 Receptor (MC1R) could influence catalase expression, activity and cellular localization. For this purpose, we treated B16-F0 melanoma cells with α-Melanocyte Stimulating Hormone (α-MSH) and we showed a rapid induction of catalase through a cAMP/PKA-dependent, microphthalmia-associated transcription factor (MITF) independent mechanism, acting at post-transcriptional level. Moreover, α-MSH promoted a partial re-distribution of catalase to the cell periphery and dendrites. This work strengthens the correlation between melanogenesis and anti-oxidants, demonstrating the induction of catalase in response to a melanogenic stimulation, such as α-MSH-dependent MC1R activation. Moreover, this study highlights catalase regulatory mechanisms poorly known, and attributes to α-MSH a protective role in defending melanocytes, and possibly keratinocytes, not only on the basis of its pigmentary action, but also for its capacity to stimulate a quick anti-oxidant defence. [ABSTRACT FROM AUTHOR]

Proton motive force (pmf) across thylakoid membranes is not only for harnessing solar energy for photosynthetic CO2 fixation, but also for triggering feedback regulation of photosystem II antenna. The mechanisms for balancing these two roles of the proton circuit under the long-term environmental stress, such as prolonged drought, have been poorly understood. In this study, we report on the response of wild watermelon thylakoid ‘proton circuit’ to drought stress using both in vivo spectroscopy and molecular analyses of the representative photosynthetic components. Although drought stress led to enhanced proton flux via a ∼34% increase in cyclic electron flow around photosystem I (PS I), an observed ∼fivefold decrease in proton conductivity, gH+, across thylakoid membranes suggested that decreased ATP synthase activity was the major factor for sustaining elevated qE. Western blotting analyses revealed that ATP synthase content decreased significantly, suggesting that quantitative control of the complex plays a pivotal role in down-regulation of gH+. The expression level of cytochrome b6 f complex – another key control point in photosynthesis – also declined, probably to prevent excess-reduction of PS I electron acceptors. We conclude that plant acclimation to long-term environmental stress involves global changes in the photosynthetic proton circuit, in which ATP synthase represents the key control point for regulating the relationship between electron transfer and pmf. [ABSTRACT FROM AUTHOR]