Antenna protein aggregation is one of the principal mechanisms considered effective in protecting phototrophs against high light damage. Commonly, it is induced, in vitro, by decreasing detergent concentration and pH of a solution of purified antennas; the resulting reduction in fluorescence emission is considered to be representative of non-photochemical quenching in vivo. However, little is known about the actual size and organization of antenna particles formed by this means, and hence the physiological relevance of this experimental approach is questionable. Here, a quasi-single molecule method, fluorescence correlation spectroscopy (FCS), was applied during in vitro quenching of LHCII trimers from higher plants for a parallel estimation of particle size, fluorescence, and antenna cluster homogeneity in a single measurement. FCS revealed that, below detergent critical micelle concentration, low pH promoted the formation of large protein oligomers of sizes up to micrometers, and therefore is apparently incompatible with thylakoid membranes. In contrast, LHCII clusters formed at high pH were smaller and homogenous, and yet still capable of efficient quenching. The results altogether set the physiological validity limits of in vitro quenching experiments. Our data also support the idea that the small, moderately quenching LHCII oligomers found at high pH could be relevant with respect to non-photochemical quenching in vivo.

• Klíčová slova
• antenna proteins, detergent critical micelle concentration, fluorescence correlation spectroscopy, non-photochemical quenching, photoprotection, photosynthesis, protein oligomerization,
• MeSH
• chlorofyl chemie   genetika   účinky záření   MeSH
• fluorescence MeSH
• fluorescenční spektrometrie MeSH
• fotosyntéza genetika   MeSH
• fotosystém II (proteinový komplex) genetika   účinky záření   MeSH
• fototrofní procesy genetika   MeSH
• homeodoménový protein Antennapedia chemie   genetika   MeSH
• koncentrace vodíkových iontů MeSH
• proteinové agregáty genetika   MeSH
• shluková analýza MeSH
• světlo škodlivé účinky   MeSH
• světlosběrné proteinové komplexy chemie   genetika   MeSH
• tylakoidy chemie   genetika   účinky záření   MeSH
• zeaxanthiny genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chlorofyl MeSH
• fotosystém II (proteinový komplex) MeSH
• homeodoménový protein Antennapedia MeSH
• proteinové agregáty MeSH
• světlosběrné proteinové komplexy MeSH
• zeaxanthiny MeSH

Tocopherols, lipid-soluble antioxidants play a crucial role in the antioxidant defense system in higher plants. The antioxidant function of α-tocopherol has been widely studied; however, experimental data on the formation of its oxidation products is missing. In this study, we attempt to provide spectroscopic evidence on the detection of oxidation products of α-tocopherol formed by its interaction with singlet oxygen and lipid peroxyl radical. Singlet oxygen was formed using photosensitizer rose bengal and thylakoid membranes isolated from Arabidopsis thaliana. Singlet oxygen reacts with polyunsaturated fatty acid forming lipid hydroperoxide which is oxidized by ferric iron to lipid peroxyl radical. The addition of singlet oxygen to double bond carbon on the chromanol head of α-tocopherol forms α-tocopherol hydroperoxide detected using fluorescent probe swallow-tailed perylene derivative. The decomposition of α-tocopherol hydroperoxide forms α-tocopherol quinone. The hydrogen abstraction from α-tocopherol by lipid peroxyl radical forms α-tocopheroxyl radical detected by electron paramagnetic resonance. Quantification of lipid and protein hydroperoxide from the wild type and tocopherol deficient (vte1) mutant Arabidopsis leaves using a colorimetric ferrous oxidation-xylenol orange assay reveals that α-tocopherol prevents formation of both lipid and protein hydroperoxides at high light. Identification of oxidation products of α-tocopherol might contribute to a better understanding of the protective role of α-tocopherol in the prevention of oxidative damage in higher plants at high light.

• MeSH
• alfa-tokoferol chemie   metabolismus   MeSH
• antioxidancia chemie   metabolismus   MeSH
• Arabidopsis genetika   růst a vývoj   metabolismus   účinky záření   MeSH
• lipidové peroxidy chemie   metabolismus   MeSH
• oxidace-redukce MeSH
• oxidační stres * MeSH
• peroxid vodíku chemie   metabolismus   MeSH
• singletový kyslík chemie   metabolismus   MeSH
• světlo škodlivé účinky   MeSH
• vitamin E chemie   metabolismus   MeSH
• volné radikály chemie   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• alfa-tokoferol MeSH
• antioxidancia MeSH
• lipidové peroxidy MeSH
• peroxid vodíku MeSH
• singletový kyslík MeSH
• tocopheroxy radical MeSH Prohlížeč
• vitamin E MeSH
• volné radikály MeSH

OBJECTIVE: The aim of the study was to examine subjective sleep quality in a population of healthy volunteers and its association with evening and night light exposure to screens of media devices. METHODS: A total of 693 participants (mean age 31.2±11.4 years, 159 men, and 538 women) completed an online questionnaire battery consisting of several sleep-related questionnaires: PSQI, FSS, MCTQ, MEQ, and added questions assessing the timing and character the evening and night exposure to electronical devices (TV, PC, tablets, and phones), and the use of various filters blocking short-wavelength light. RESULTS: Statistical analyses show that longer cumulative exposure to screen light in the evening was associated with greater sleep inertia in the morning (P = .019, η2=0.141) and longer sleep latency on workdays P = .038, η2=0.135). Furthermore, exposure to screen light 1.5 h before sleep or during night awakenings was also associated with a decreased chance to wake up before alarm clock (P = .003, d=0.30), larger social jet lag (P < .001, d=0.15), more daytime dysfunction (P < .001, d=0.40), decreased subjective sleep quality (P = .024, d=0.16), and more fatigue (P < .001, d=0.52). A statistical trend for an increase in duration of sleep on weekdays (P = .058, d=0.23) was also found in participants using blue-light filters in the evening hours. DISCUSSION: Our results are in line with other studies that converge to show the negative association of evening and night exposure to short-wavelength light on subjective and objective sleep parameters. Results suggest that light hygiene in general population should be given more attention not only in the context of clinical sleep medicine but also in the realm of public health.

• Klíčová slova
• Blue-light, Fatigue, Screen exposure, Sleep, Sleep inertia, Sleep quality,
• MeSH
• čas strávený před obrazovkou * MeSH
• časové faktory MeSH
• dospělí MeSH
• lidé MeSH
• průzkumy a dotazníky MeSH
• spánek * MeSH
• světlo škodlivé účinky   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The anoxygenic phototrophic bacteria (APB) are an active component of aquatic microbial communities. While DNA-based studies have delivered a detailed picture of APB diversity, they cannot provide any information on the activity of individual species. Therefore, we focused on the expression of a photosynthetic gene by APB communities in two freshwater lakes (Cep lake and the Římov Reservoir) in the Czech Republic. First, we analyzed expression levels of pufM during the diel cycle using RT-qPCR. The transcription underwent a strong diel cycle and was inhibited during the day in both lakes. Then, we compared DNA- (total) and RNA-based (active) community composition by sequencing pufM amplicon libraries. We observed large differences in expression activity among different APB phylogroups. While the total APB community in the Římov Reservoir was dominated by Betaproteobacteria, Alphaproteobacteria prevailed in the active library. A different situation was encountered in the oligotrophic lake Cep where Betaproteobacteria (order Burkholderiales) dominated both the DNA and RNA libraries. Interestingly, in Cep lake we found smaller amounts of highly active uncultured phototrophic Chloroflexi, as well as phototrophic Gemmatimonadetes. Despite the large diversity of APB communities, light repression of pufM expression seems to be a common feature of all aerobic APB present in the studied lakes.

• MeSH
• Alphaproteobacteria izolace a purifikace   fyziologie   účinky záření   MeSH
• bakteriální proteiny genetika   metabolismus   MeSH
• Betaproteobacteria izolace a purifikace   fyziologie   účinky záření   MeSH
• DNA bakterií genetika   izolace a purifikace   MeSH
• fotoperioda * MeSH
• fotosyntetická reakční centra (proteinové komplexy) genetika   metabolismus   MeSH
• fototrofní procesy genetika   účinky záření   MeSH
• fylogeneze MeSH
• jezera mikrobiologie   MeSH
• mikrobiota fyziologie   účinky záření   MeSH
• regulace genové exprese u bakterií fyziologie   účinky záření   MeSH
• světlo škodlivé účinky   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH
• Názvy látek
• bakteriální proteiny MeSH
• DNA bakterií MeSH
• fotosyntetická reakční centra (proteinové komplexy) MeSH
• PufM protein, Bacteria MeSH Prohlížeč

Light pollution is increasing worldwide and significantly affects animal behavior. In birds, these effects include advancement of morning activity and onset of dawn song, which may affect extra-pair paternity. Advanced dawn song of males may stimulate females to engage in extra-pair copulations, and the earlier activity onset may affect the males' mate guarding behavior. Earlier work showed an effect of light at night on extra-pair behavior, but this was in an area with other anthropogenic disturbances. Here, we present a two-year experimental study on effects of light at night on extra-pair paternity of great tits (Parus major). Previously dark natural areas were illuminated with white, red, and green LED lamps and compared to a dark control. In 2014, the proportion of extra-pair young in broods increased with distance to the red and white lamps (i.e., at lower light intensities), but decreased with distance to the poles in the dark control. In 2013, we found no effects on the proportion of extra-pair young. The total number of offspring sired by a male was unaffected by artificial light at night in both years, suggesting that potential changes in female fidelity in pairs breeding close to white and red light did not translate into fitness benefits for the males of these pairs. Artificial light at night might disrupt the natural patterns of extra-pair paternity, possibly negates potential benefits of extra-pair copulations and thus could alter sexual selection processes in wild birds.

• Klíčová slova
• Parus major, artificial light at night, extra-pair paternity, great tit, light color, light pollution,
• MeSH
• barva * MeSH
• osvětlení škodlivé účinky   MeSH
• Passeriformes fyziologie   MeSH
• sexuální chování zvířat účinky záření   MeSH
• světlo škodlivé účinky   MeSH
• vystavení vlivu životního prostředí MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

Lactacystin is a proteasome inhibitor that interferes with several factors involved in heart remodelling. The aim of this study was to investigate whether the chronic administration of lactacystin induces hypertension and heart remodelling and whether these changes can be modified by captopril or melatonin. In addition, the lactacystin-model was compared with NG-nitro-l-arginine-methyl ester (L-NAME)- and continuous light-induced hypertension. Six groups of three-month-old male Wistar rats (11 per group) were treated for six weeks as follows: control (vehicle), L-NAME (40 mg/kg/day), continuous light (24 h/day), lactacystin (5 mg/kg/day) alone, and lactacystin with captopril (100 mg/kg/day), or melatonin (10 mg/kg/day). Lactacystin treatment increased systolic blood pressure (SBP) and induced fibrosis of the left ventricle (LV), as observed in L-NAME-hypertension and continuous light-hypertension. LV weight and the cross-sectional area of the aorta were increased only in L-NAME-induced hypertension. The level of oxidative load was preserved or reduced in all three models of hypertension. Nitric oxide synthase (NOS) activity in the LV and kidney was unchanged in the lactacystin group. Nuclear factor-kappa B (NF-κB) protein expression in the LV was increased in all treated groups in the cytoplasm, however, in neither group in the nucleus. Although melatonin had no effect on SBP, only this indolamine (but not captopril) reduced the concentration of insoluble and total collagen in the LV and stimulated the NO-pathway in the lactacystin group. We conclude that chronic administration of lactacystin represents a novel model of hypertension with collagenous rebuilding of the LV, convenient for testing antihypertensive drugs or agents exerting a cardiovascular benefit beyond blood pressure reduction.

• Klíčová slova
• captopril, fibrosis, hypertension, lactacystin, melatonin, remodelling,
• MeSH
• acetylcystein škodlivé účinky   analogy a deriváty   MeSH
• antihypertenziva aplikace a dávkování   farmakologie   MeSH
• fibróza MeSH
• hypertenze chemicky indukované   farmakoterapie   etiologie   MeSH
• kaptopril aplikace a dávkování   farmakologie   MeSH
• krysa rodu Rattus MeSH
• melatonin aplikace a dávkování   farmakologie   MeSH
• modely nemocí na zvířatech MeSH
• NG-nitroargininmethylester škodlivé účinky   MeSH
• potkani Wistar MeSH
• remodelace komor účinky léků   MeSH
• srdeční komory účinky léků   patologie   MeSH
• světlo škodlivé účinky   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH
• Názvy látek
• acetylcystein MeSH
• antihypertenziva MeSH
• kaptopril MeSH
• lactacystin MeSH Prohlížeč
• melatonin MeSH
• NG-nitroargininmethylester MeSH

Chronic continuous light exposure leads to melatonin deficiency along with complex neurohumoral activation resulting in hypertension development in rats. The aim of this study was to show, whether continuous light induces fibrotic rebuilding of the aorta and whether the treatment with melatonin or angiotensin converting enzyme inhibitor captopril can prevent these potential alterations. In a six-week experiment, 3-month-old Wistar rats were divided into 4 groups (ten per group): controls, rats exposed to continuous light, exposed to continuous light plus treated with captopril (100 mg/kg/24 h) and exposed to continuous light plus treated with melatonin (10 mg/kg/24 h). Systolic blood pressure (SBP) and collagen type I and III in the media of thoracic aorta were measured. Continuous light induced hypertension and fibrotic rebuilding of the aorta in terms of enhancement of collagen I and III concentration in the aortic media. Both captopril and melatonin prevented SBP rise and reduced collagen III concentration in the aorta. However, only melatonin reduced collagen I and the sum of collagen I and III in the aortic tissue. We conclude that in continuous light-induced hypertension, administration of melatonin, along with SBP reduction, decreases collagen I and III concentration in the aorta. It is suggested that antifibrotic effect of melatonin may reduce the stiffness of the aorta and small arteries and beneficially influence the nature of the pulse wave and peripheral vascular resistance.

• MeSH
• antifibrinolytika aplikace a dávkování   MeSH
• antihypertenziva aplikace a dávkování   MeSH
• aorta účinky léků   patofyziologie   MeSH
• fibrilární kolageny metabolismus   MeSH
• hypertenze etiologie   patofyziologie   prevence a kontrola   MeSH
• kaptopril aplikace a dávkování   MeSH
• krysa rodu Rattus MeSH
• melatonin aplikace a dávkování   MeSH
• potkani Wistar MeSH
• světelná stimulace škodlivé účinky   MeSH
• světlo škodlivé účinky   MeSH
• tuhost cévní stěny účinky léků   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antifibrinolytika MeSH
• antihypertenziva MeSH
• fibrilární kolageny MeSH
• kaptopril MeSH
• melatonin MeSH

Photosynthesis uses light as a source of energy but its excess can result in production of harmful oxygen radicals. To avoid any resulting damage, phototrophic organisms can employ a process known as non-photochemical quenching (NPQ), where excess light energy is safely dissipated as heat. The mechanism(s) of NPQ vary among different phototrophs. Here, we describe a new type of NPQ in the organism Rhodomonas salina, an alga belonging to the cryptophytes, part of the chromalveolate supergroup. Cryptophytes are exceptional among photosynthetic chromalveolates as they use both chlorophyll a/c proteins and phycobiliproteins for light harvesting. All our data demonstrates that NPQ in cryptophytes differs significantly from other chromalveolates - e.g. diatoms and it is also unique in comparison to NPQ in green algae and in higher plants: (1) there is no light induced xanthophyll cycle; (2) NPQ resembles the fast and flexible energetic quenching (qE) of higher plants, including its fast recovery; (3) a direct antennae protonation is involved in NPQ, similar to that found in higher plants. Further, fluorescence spectroscopy and biochemical characterization of isolated photosynthetic complexes suggest that NPQ in R. salina occurs in the chlorophyll a/c antennae but not in phycobiliproteins. All these results demonstrate that NPQ in cryptophytes represents a novel class of effective and flexible non-photochemical quenching.

• MeSH
• buněčná membrána metabolismus   účinky záření   MeSH
• Cryptophyta cytologie   enzymologie   metabolismus   účinky záření   MeSH
• fotosystém II (proteinový komplex) metabolismus   MeSH
• kinetika MeSH
• koncentrace vodíkových iontů MeSH
• kvarterní struktura proteinů MeSH
• multimerizace proteinu účinky záření   MeSH
• proteiny vázající chlorofyl chemie   metabolismus   MeSH
• protony MeSH
• substrátová specifita MeSH
• světlo škodlivé účinky   MeSH
• xanthofyly metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fotosystém II (proteinový komplex) MeSH
• proteiny vázající chlorofyl MeSH
• protony MeSH
• xanthofyly MeSH

Bright light is a treatment of choice for seasonal affective disorder. Other indications for bright light therapy have also been tested. These include non-seasonal depression, bipolar depression, chronic depressive disorder, ante- and postpartum depression, late luteal phase dysphoric disorder, circadian phase sleep disorders, jet lag, shift work problems, and behavioral disturbance and insomnia in organic dementia. Future studies should focus on exploring the use of light therapy in combination with sleep deprivation, other classes of antidepressants, and with psychotherapy and their possible combined effect on subtypes of depression or other mentioned diagnoses, light treatment duration, and the applicability and efficacy of adjunct light treatment for in-patients.

• MeSH
• cirkadiánní rytmus fyziologie   MeSH
• depresivní poruchy terapie   MeSH
• fototerapie * škodlivé účinky   metody   MeSH
• lidé MeSH
• roční období MeSH
• sezónní afektivní porucha terapie   MeSH
• světlo škodlivé účinky   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

Photodynamic therapy (PDT) of malignant processes is based on the ability of a photosensitizer to first, accumulate in malignant (immature) tissue and second, to be destroyed following light irradiation. Because of the similarity between malignant and embryonic immature tissues, we investigated the deleterious effect of the PDT procedure on day 4 chick embryos in ovo. We compared experimentally the photodynamic effect (light-toxic) and the side effect (dark-toxic) of the clinically attractive photosensitizers 5-aminolevulinic acid (ALA) and protoporphyrin IX (PP IX). The dark and light embryotoxicity (i.e. lethality plus teratogenicity) was determined after intra-amniotic injection of one of a range of dose of each compound. Under dark conditions, PP IX exhibited embryotoxicity at a dose of 10 microg/embryo; however ALA did not exhibit embryotoxicity even at the highest dose (300 microg/embryo). Light irradiation of embryos following injection induced strong embryotoxic effects of both substances even at dark-ineffective doses.

• MeSH
• abnormality vyvolané léky * MeSH
• fotosenzibilizující látky aplikace a dávkování   toxicita   MeSH
• kuřecí embryo účinky léků   účinky záření   MeSH
• kyselina aminolevulová aplikace a dávkování   toxicita   MeSH
• liposomy MeSH
• protoporfyriny aplikace a dávkování   toxicita   MeSH
• světlo škodlivé účinky   MeSH
• tma škodlivé účinky   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• ztráta embrya chemicky indukované   MeSH
• zvířata MeSH
• Check Tag
• kuřecí embryo účinky léků   účinky záření   MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fotosenzibilizující látky MeSH
• kyselina aminolevulová MeSH
• liposomy MeSH
• protoporfyriny MeSH
• protoporphyrin IX MeSH Prohlížeč