Chlorosomes of green photosynthetic bacteria are large light-harvesting complexes enabling these organisms to survive at extremely low-light conditions. Bacteriochlorophylls found in chlorosomes self-organize and are ideal candidates for use in biomimetic light-harvesting in artificial photosynthesis and other applications for solar energy utilization. Here we report on the construction and characterization of an artificial antenna consisting of bacteriochlorophyll c co-aggregated with β-carotene, which is used to extend the light-harvesting spectral range, and bacteriochlorophyll a, which acts as a final acceptor for excitation energy. Efficient energy transfer between all three components was observed by means of fluorescence spectroscopy. The efficiency varies with the β-carotene content, which increases the average distance between the donor and acceptor in both energy transfer steps. The efficiency ranges from 89 to 37% for the transfer from β-carotene to bacteriochlorophyll c, and from 93 to 69% for the bacteriochlorophyll c to bacteriochlorophyll a step. A significant part of this study was dedicated to a development of methods for determination of energy transfer efficiency. These methods may be applied also for study of chlorosomes and other pigment complexes.

• Klíčová slova
• Artificial light-harvesting antenna, Bacteriochlorophyll aggregates, Chlorosomes, Efficiency of excitation energy transfer, Fluorescence spectroscopy,
• MeSH
• bakteriální proteiny metabolismus   MeSH
• bakteriochlorofyl A * chemie   MeSH
• bakteriochlorofyly * chemie   MeSH
• beta-karoten MeSH
• fotosyntéza MeSH
• přenos energie MeSH
• světlosběrné proteinové komplexy chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• bakteriální proteiny MeSH
• bakteriochlorofyl A * MeSH
• bakteriochlorofyly * MeSH
• beta-karoten MeSH
• světlosběrné proteinové komplexy MeSH

Thraustochytrids (phylum: Labyrinthulomycota) are nonphotosynthetic marine protists. Some thraustochytrids have crtIBY, a trifunctional fusion gene encoding a protein capable of β-carotene biosynthesis from geranylgeranyl pyrophosphate. Here we show that crtIBY is essential in, and encodes the sole pathway for, carotenoid biosynthesis in the thraustochytrid Aurantiochytrium limacinum ATCC MYA-1381. We explore the evolutionary origins of CrtIBY and discover that the closest related protein domains are present in a small but diverse group of other heterotrophic protists, including the apusomonad Thecamonas trahens and the dinoflagellates Oxyrrhis marina and Noctiluca scintillans. Each organism within this cluster also contains one or more β-carotene 15-15' oxygenase genes (blh and rpe65), suggesting that the acquisition of β-carotene biosynthesis genes may have been related to the production of retinal. Our findings support a novel origin of eukaryotic (apo)carotenoid biosynthesis by horizontal gene transfer from Actinobacteria, Bacteroidetes, and/or Archaea. This reveals a remarkable case of parallel evolution of eukaryotic (apo)carotenogenesis in divergent protistan lineages by repeated gene transfers.

• Klíčová slova
• carotenoid oxygenase, lycopene cyclase, phylogenetics, phytoene desaturase, phytoene synthase, thraustochytrids,
• MeSH
• Bacteria genetika   MeSH
• beta-karoten genetika   MeSH
• Heterokontophyta * MeSH
• karotenoidy * MeSH
• přenos genů horizontální MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Názvy látek
• beta-karoten MeSH
• karotenoidy * MeSH

Eight miniaturized Raman spectrometers were used to perform a fast outdoor screening and discrimination of carotenoids of a series of halophilic and non-halophilic microorganisms on a set of eight lyophilized samples, each containing high concentrations of a specific dominant carotenoid pigment. Raman spectra were acquired using different excitations (532, 785, sequentially shifted excitation of 785 and 853, and 1064 nm), based on the model of each Raman spectrometer, in order to ascertain the feasibility of individual wavelengths. The wavenumber positions of diagnostic Raman bands of carotenoids were observed for the different carotenoid species. Characteristic carotenoid Raman bands of the pigment bacterioruberin were reported (using the 532 nm excitation) at 1504-1509 cm-1, salinixanthin at 1510-1513 cm-1, spirilloxanthin at 1509-1513 cm-1, decaprenoxanthin at 1519 cm-1, β-carotene at 1526 cm-1, and sarcinaxanthin at 1526-1528 cm-1. A 532 nm excitation consistently provided best results due to the significant resonance signal enhancement (both quantitative and qualitative carotenoid detection). Good results were also obtained using the sequentially shifted excitation combining two lasers in the near infrared spectral region, and similarly good results were acquired using a standard 1064 nm excitation. The least suitable was a 785 nm excitation, with the carotenoid Raman signal almost always weaker compared to major fluorescence signal arising from other types of pigments or biomolecules in the samples. A thorough light shielding was essential in order to acquire good quality data. This study shows that miniaturized Raman spectrometers, some even equipped with longer wavelength excitation, are able to detect different carotenoid pigments under non-laboratory conditions in a fast way, and discriminate between them, to a certain degree. The implications of this type of research are especially useful in astrobiology, where the searching, detection and discrimination of biomarkers such as carotenoids is receiving significant attention.

• Klíčová slova
• Carotenoids, Halophiles, Outdoor, Portable Raman spectrometers,
• MeSH
• beta-karoten MeSH
• karotenoidy * MeSH
• lasery MeSH
• Ramanova spektroskopie * metody   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• beta-karoten MeSH
• karotenoidy * MeSH

Constraining the formation mechanisms of organic matter that persists in aquatic reservoirs is important for determining the reactivity and fate of carbon and nutrients in these environments. Recent studies have linked dissolved organic matter (DOM) accumulating in the ocean to linear terpenoid structures, and carotenoid degradation products have been proposed as potential precursors. The prevalence of reactive oxygen species in aquatic environments and their potential to be quenched by carotenoids led us to examine radical-assisted photochemical degradation of carotenoids as a potential mechanism for DOM formation and transformation. Experiments were conducted with aggregates of β-carotene, astaxanthin, fucoxanthin and meso-zeaxanthin in THF:H2O under solar light irradiation assisted by hydrogen peroxide (UV-Vis/H2O2). Based on the fine structure of UV-Vis spectra, it was determined that β-carotene and meso-zeaxanthin formed J-type aggregates in experimental solutions, while astaxanthin and fucoxanthin formed H2-type aggregates, consistent with their structural characteristics. All carotenoids degraded under the combined influence of photolysis and OH scavenging, with fucoxanthin exhibiting the fastest degradation kinetics (kPO = 3.69 10-3 s-1) and meso-zeaxanthin the slowest (kPO = 4.37 10-4 s-1). The major degradation products detected by electrospray ionization (ESI) tandem mass spectrometry (MS/MS) were apo-aldehydes and apo-ketones, with the latter tending to accumulate, but epoxidation of the carotenoids also took place, and longer irradiation times resulted in lower molecular weight products. Reaction kinetics and accumulating carotenoid oxidation products identified in this study provide potential formation mechanisms and biomarkers for examining DOM cycling.

• Klíčová slova
• Aggregates, Carotenoids, Kinetics, Oxidation products, Solar irradiation,
• MeSH
• beta-karoten MeSH
• karotenoidy * MeSH
• kinetika MeSH
• peroxid vodíku * MeSH
• tandemová hmotnostní spektrometrie MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• beta-karoten MeSH
• karotenoidy * MeSH
• peroxid vodíku * MeSH

Wild edible plants have become an attractive variation of the human diet, especially in East Asia, North America, and Oceania. However, their potential in nutrition is only rarely considered in Europe. This study aims to reveal the nutritional and antioxidant potential of mature fern leaves from 13 families grown in Europe. We found that most of the examined fern species displayed a high antioxidant capacity, exceeding 0.5 g Trolox equivalent per gram of extract dry weight in ORAC assay and reaching IC50 values lower than 30 µg·mL-1 in DPPH assay (with the value for Trolox 7 µg·mL-1). Most of the species also appeared to be a good source of carotenoids, especially of lutein (205 µg·g-1 DW on average) and β-carotene (161 µg·g-1 DW on average) when compared to the reference leafy vegetables spinach and rocket. A cytotoxicity test using ovine hepatocytes showed a non-toxicity effect of fern leaf extracts.

• Klíčová slova
• Antioxidant capacity, Carotenoids, Ferns, Lutein, Monilophytes, Nutrition, Phenols,
• MeSH
• antioxidancia chemie   farmakologie   MeSH
• beta-karoten analýza   MeSH
• dieta * MeSH
• hepatocyty účinky léků   MeSH
• jedlé rostliny chemie   MeSH
• kapradiny chemie   MeSH
• karotenoidy analýza   MeSH
• lidé MeSH
• lutein analýza   MeSH
• ovce MeSH
• viabilita buněk účinky léků   MeSH
• zelenina chemie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Evropa MeSH
• Názvy látek
• antioxidancia MeSH
• beta-karoten MeSH
• karotenoidy MeSH
• lutein MeSH

Significant improvements in the voltammetric determination of β-carotene (BCA) have been achieved, mainly by the replacement of toxic dichloromethane with acetone and using non-mercury electrode. The respective procedure is based on anodic oxidation of BCA at a gold electrode in the disc configuration, when using square-wave voltammetry in pure acetone (99.8%) with 0.1 mol L-1 LiClO4 as the supporting electrolyte. The method comprises extraction of the analyte from the sample with acetone, thus avoiding the usually used highly toxic solvents. Analytically, it can be characterized by a linear range from 6.0 × 10-6 to 5.9 × 10-4 mol L-1 with regression equation Ipa = 0.0184c -0.1631 and correlation coefficient, R2 = 0.9998, limits of detection and quantification LOD = 1.6 × 10-6 mol L-1 and LOQ = 5.4 × 10-6 mol L-1, respectively; both being obtained at a potential step of 5 mV, with the pulse amplitude of 25 mV, and a frequency of 80 Hz. After optimization, the method was evaluated in series of analyses; namely, with two samples of vegetables and two pharmaceutical preparations (capsules), when the results could be compared to those of a reference spectrophotometric method. Due to a simple instrumentation, including sample preparation, the voltammetric method for the determination of BCA can be recommended as a quick screening assay in food and pharmaceutical analysis.

• Klíčová slova
• Food and pharmaceutical samples, Gold disk electrode, Square-wave voltammetry, β-Carotene,
• MeSH
• beta-karoten MeSH
• elektrochemie MeSH
• elektrody MeSH
• tobolky MeSH
• zelenina * MeSH
• zlato * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• beta-karoten MeSH
• tobolky MeSH
• zlato * MeSH

OBJECTIVES: Previous research has shown that nutrition can influence cognitive abilities in older adults. We examined whether nutritional factors or inflammatory biomarkers moderate the age-cognition association. METHOD: Analyses included 1,308 participants (age ≥60) from the National Health and Nutrition Examination Survey III. Macronutrients (% of calories from fat, protein, and carbohydrates), micronutrients/amino acids (blood serum values: Vitamins B12, C, D, E, folate, iron, homocysteine, and β-carotene), and inflammatory biomarkers (serum C-reactive protein, plasma fibrinogen, and serum ferritin) were examined as moderators with cognition. Cognition was measured by six tasks: immediate and delayed story recall, immediate and delayed word memory, digit subtraction, and questions about place/orientation. RESULTS: Higher values of serum folate were significantly associated with better cognitive scores. Specifically, the interaction between age-cognition and folate indicated the associations of higher age and lower global cognition and lower immediate story recall were weaker in those with higher folate values (p's < .05). A significant interaction between age and plasma fibrinogen indicated that the association between age and worse digit subtraction was stronger with values >3.1 g/L. DISCUSSION: Folate and fibrinogen were significant moderators between age and cognition. Further research into the relationship between nutrition, inflammation, and cognitive aging is needed.

• MeSH
• beta-karoten krev   MeSH
• biologické markery krev   MeSH
• C-reaktivní protein analýza   MeSH
• dieta statistika a číselné údaje   MeSH
• ferritiny krev   MeSH
• fibrinogen analýza   MeSH
• homocystein krev   MeSH
• kognice * MeSH
• kognitivní dysfunkce krev   etiologie   MeSH
• kyselina listová krev   MeSH
• lidé středního věku MeSH
• lidé MeSH
• neuropsychologické testy MeSH
• nutriční stav * MeSH
• senioři MeSH
• věkové faktory MeSH
• vitaminy krev   MeSH
• výživa - přehledy MeSH
• zánět krev   komplikace   MeSH
• železo krev   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• beta-karoten MeSH
• biologické markery MeSH
• C-reaktivní protein MeSH
• ferritiny MeSH
• fibrinogen MeSH
• homocystein MeSH
• kyselina listová MeSH
• vitaminy MeSH
• železo MeSH

β-carotene is a natural compound with significant antioxidant activity. However, its poor solubility in water and low stability reduce its potential application. Innovative polyplexes based on the combination of amphiphilic chitosan assembled with DNA have been developed using a solvent-free, simple and low-cost method with the aim to load, retain and enhance the antioxidant capability of β-carotene. The polyplexes, with dimension about 100 nm, and excellent stability, were able to hold up to 400 μg of β-carotene per mg of the carrier, with minimal loss till two weeks. The antioxidant activity was significantly enhanced after loading, as demonstrated using two well known methods. Cytotoxicity assay confirmed the not toxicity of the system. The results suggest the polyplexes as an excellent candidate to develop formulation able to preserve and enhance the peculiarities of compounds which are used mainly in food, cosmetic and pharmaceutic but with still some limitations.

• Klíčová slova
• Antioxidants, Chitosan, Deoxyribonucleic acid, Polylactic acid, Polyplexes, β-carotene,
• MeSH
• antioxidancia chemie   farmakologie   toxicita   MeSH
• beta-karoten chemie   farmakologie   toxicita   MeSH
• bifenylové sloučeniny chemie   MeSH
• buňky NIH 3T3 MeSH
• chitosan chemie   MeSH
• DNA chemie   MeSH
• hydrofobní a hydrofilní interakce * MeSH
• myši MeSH
• pikráty chemie   MeSH
• rozpustnost MeSH
• stabilita léku MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 1,1-diphenyl-2-picrylhydrazyl MeSH Prohlížeč
• antioxidancia MeSH
• beta-karoten MeSH
• bifenylové sloučeniny MeSH
• chitosan MeSH
• DNA MeSH
• pikráty MeSH

Cyanobacteria possess a family of one-helix high-light-inducible proteins (HLIPs) that are widely viewed as ancestors of the light-harvesting antenna of plants and algae. HLIPs are essential for viability under various stress conditions, although their exact role is not fully understood. The unicellular cyanobacterium Synechocystis sp. PCC 6803 contains four HLIPs named HliA-D, and HliD has recently been isolated in a small protein complex and shown to bind chlorophyll and β-carotene. However, no HLIP has been isolated and characterized in a pure form up to now. We have developed a protocol to purify large quantities of His-tagged HliC from an engineered Synechocystis strain. Purified His-HliC is a pigmented homo-oligomer and is associated with chlorophyll and β-carotene with a 2:1 ratio. This differs from the 3:1 ratio reported for HliD. Comparison of these two HLIPs by resonance Raman spectroscopy revealed a similar conformation for their bound β-carotenes, but clear differences in their chlorophylls. We present and discuss a structural model of HliC, in which a dimeric protein binds four chlorophyll molecules and two β-carotenes.

• Klíčová slova
• Chlorophyll, HLIPs, HliC, Raman spectroscopy, Synechocystis, β-Carotene,
• MeSH
• bakteriální proteiny chemie   genetika   izolace a purifikace   metabolismus   MeSH
• beta-karoten metabolismus   MeSH
• chlorofyl metabolismus   MeSH
• multimerizace proteinu MeSH
• Ramanova spektroskopie MeSH
• rekombinantní proteiny genetika   izolace a purifikace   metabolismus   MeSH
• světlosběrné proteinové komplexy genetika   metabolismus   MeSH
• Synechocystis genetika   metabolismus   fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• bakteriální proteiny MeSH
• beta-karoten MeSH
• chlorofyl MeSH
• high light-inducible protein, cyanobacteria MeSH Prohlížeč
• rekombinantní proteiny MeSH
• světlosběrné proteinové komplexy MeSH

Polyunsaturated lipids are important components of photosynthetic membranes. Xanthophylls are the main photoprotective agents, can assist in protection against light stress, and are crucial in the recovery from photoinhibition. We generated the xanthophyll- and polyunsaturated lipid-deficient ROAD mutant of Synechocystis sp. PCC6803 (Synechocystis) in order to study the little-known cooperative effects of lipids and carotenoids (Cars). Electron microscopic investigations confirmed that in the absence of xanthophylls the S-layer of the cellular envelope is missing. In wild-type (WT) cells, as well as the xanthophyll-less (RO), polyunsaturated lipid-less (AD), and the newly constructed ROAD mutants the lipid and Car compositions were determined by MS and HPLC, respectively. We found that, relative to the WT, the lipid composition of the mutants was remodeled and the Car content changed accordingly. In the mutants the ratio of non-bilayer-forming (NBL) to bilayer-forming (BL) lipids was found considerably lower. Xanthophyll to β-carotene ratio increased in the AD mutant. In vitro and in vivo methods demonstrated that saturated, monounsaturated lipids and xanthophylls may stabilize the trimerization of Photosystem I (PSI). Fluorescence induction and oxygen-evolving activity measurements revealed increased light sensitivity of RO cells compared to those of the WT. ROAD showed a robust increase in light susceptibility and reduced recovery capability, especially at moderate low (ML) and moderate high (MH) temperatures, indicating a cooperative effect of xanthophylls and polyunsaturated lipids. We suggest that both lipid unsaturation and xanthophylls are required for providing the proper structure and functioning of the membrane environment that protects against light and temperature stress.

• Klíčová slova
• Cyanobacteria, Lipid remodeling, Lipid-carotenoid-protein interactions, Photoinhibition, Temperature stress, Xanthophylls,
• MeSH
• beta-karoten metabolismus   účinky záření   MeSH
• buněčná membrána genetika   metabolismus   účinky záření   ultrastruktura   MeSH
• časové faktory MeSH
• fenotyp MeSH
• fotosyntéza genetika   účinky záření   MeSH
• fotosystém I (proteinový komplex) genetika   metabolismus   účinky záření   MeSH
• fyziologická adaptace MeSH
• fyziologický stres * MeSH
• genotyp MeSH
• membránové lipidy metabolismus   účinky záření   MeSH
• metabolismus lipidů genetika   účinky záření   MeSH
• mutace MeSH
• světlo * MeSH
• Synechocystis genetika   metabolismus   účinky záření   ultrastruktura   MeSH
• teplota * MeSH
• tylakoidy metabolismus   účinky záření   MeSH
• xanthofyly genetika   metabolismus   účinky záření   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Názvy látek
• beta-karoten MeSH
• fotosystém I (proteinový komplex) MeSH
• membránové lipidy MeSH
• xanthofyly MeSH