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Carotenoids belong to one of the most common classes of biological pigments. They are observed in either free form (dissolved in hydrophobic media) or as stoichiometric complexes with protein (carotenoproteins). An interaction between a carotenoid and a protein environment is determined mainly by the molecular conformation and dynamic behavior of a cofactor pigment. In this study, using molecular modeling methods, we have analyzed the whole set of alternative conformational states of cyclic side groups of carotenoids and evaluated the energy effects of their interaction with the conjugated backbone chain. The performed theoretical study resulted in the energy-sorted catalogue of alternative conformational states for biogenic cyclic carotenoids and their optical isomers. Conformational states described in this study can be used for a correct selection of initial conditions for the molecular modeling of carotenoproteins. [ABSTRACT FROM AUTHOR]

Our analysis of the X-ray crystal structure of canthaxanthin (CAN) showed that its ketolated β-ionone rings can adopt two energetically equal, but structurally distinct puckers. Quantum chemistry calculations revealed that the potential energy surface of the β-ionone ring rotation over the plane of the conjugated π-system in carotenoids depends on the pucker state of the β-ring. Considering different pucker states and β-ionone ring rotation, we found six separate local minima on the potential energy surface defining the geometry of the keto-β-ionone ring—two cis and one trans orientation for each of two pucker states. We observed a small difference in energy and no difference in relative orientation for the cis-minima, but a pronounced difference for the position of trans-minimum in alternative pucker configurations. An energetic advantage of β-ionone ring rotation from a specific pucker type can reach up to 8 kJ/mol ( 669 cm - 1 ). In addition, we performed the simulation of linear absorption of CAN in hexane and in a unit cell of the CAN crystal. The electronic energies of S 0 → S 2 transition were estimated both for the CAN monomer and in the CAN crystal. The difference between them reached 690 cm - 1 , which roughly corresponds to the energy gap between A and B pucker states predicted by theoretical estimations. Finally, we have discussed the importance of such effects for biological systems whose local environment determines conformational mobility, and optical/functional characteristics of carotenoid. [ABSTRACT FROM AUTHOR]

Aurantiochytrium limacinum is a heterotrophic eukaryotic microorganism that can accumulate high levels of commercial products such as astaxanthin and docosahexaenoic acid. Due to its rapid growth and relatively simple extraction method, A.limacinum is considered a promising astaxanthin resource to replace the conventional microalgal production. However, the astaxanthin biosynthetic process in A.limacinum remains incompletely understood, especially in those catalysed by β-carotene hydroxylase (CrtZ) and ketolase. In this study, we overexpressed a crtZ candidate gene to increase astaxanthin production and expand our understanding of the conversion from beta-carotene to astaxanthin. The resultant transformant AlcrtZ#10 cultivated for 5 days showed a significant increase in astaxanthin production per culture (2.8-fold) and per cell (4.5-fold) compared with that of the wild-type strain. Strikingly, longer light exposure increased astaxanthin production and decreased the beta-carotene content in the wild-type strain, suggesting that light exposure duration is important for astaxanthin production in A.limacinum. Among several predicted intermediates, furthermore, the cantaxanthin produced from β-carotene by ketolase activity were enhanced in the transformant AlcrtZ#10. Although the further investigation is needed, this result suggested that the main route of astaxanthin was via cantaxanthin. Thus, our findings will be valuable not only for its application, but also for understanding the astaxanthin biosynthetic process in A.limacinum. [ABSTRACT FROM AUTHOR]

Carotenoids are among the most widely distributed pigments in nature with broad application options in pharmacology, cosmetics and food industries. For commercial-scale production using microalgae, however, it is crucial to find the best performing strains regarding growth and yields of the products of interest. As terrestrial microalgae present the ability to quickly adapt to changing or unfavorable environmental conditions through cell-specific defense mechanisms, they constitute highly promising candidates. The present study thus aimed to investigate the potential of five terrestrial microalgal strains to increasingly produce the carotenoids β-carotene, canthaxanthin and astaxanthin when being exposed to UV-A stress. Light stress experiments were performed using a novel irradiation system based on UV-LED technology. Microalgal cultures were treated with UV-A radiation to stimulate carotenogenesis and the time-dependent effects were investigated by high-performance liquid chromatography analysis. The potential of the microalgae to enhance de novo biosynthesis of the targeted metabolites under the influence of UV-A light could be confirmed by significantly increased yields of canthaxanthin in four out of five strains and by a significantly enhanced β-carotene concentration in at least one strain during 72 h of investigation. Overall, the results provided evidence that UV-A light stress can be effective in rapidly inducing carotenogenesis in terrestrial microalgae and thus harbors vast potential for further exploitation regarding large-scale carotenoid production. [ABSTRACT FROM AUTHOR]

In this study, a water dispersible delivery system of canthaxanthin as a lipophilic keto-carotenoid pigment was developed by entrapping microbial canthaxanthin in the hydrophobic inner surface of V-amylose helix. The highest recovery yields of canthaxanthin and V-amylose from complex were observed with 20 mg of canthaxanthin and 400 mg of V-amylose. DLS analysis showed that the hydrodynamic diameter of the particles was reduced by ultrasonication to 244 nm. TEM analysis also demonstrated that particles resemble spherical or oval shape after ultrasonication. The powder dispersion remained stable after 1 month. XRD diffractograms represented the amorph structure of complex despite the crystalline structure of pure canthaxanthin, and DSC curves showed the same melting point of complex and V-amylose, both showing the change of canthaxanthin structure to amorph in the encapsulation process, indicating the complete entrapment of canthaxanthin in V-amylose helices. Oxidation stability analysis of the complex revealed an increase in the oxidation resistance of canthaxanthin. Analysis of both ABTS and DPPH radical scavenging activity by the complex showed that this feature was concentration dependent. According to the obtained results, this method is a promising way to be utilized for expanding the use of canthaxanthin in food and pharmaceutical applications with improved solubility and bioavailability.Graphical Abstract: In this study, a water dispersible delivery system of canthaxanthin as a lipophilic keto-carotenoid pigment was developed by entrapping microbial canthaxanthin in the hydrophobic inner surface of V-amylose helix. The highest recovery yields of canthaxanthin and V-amylose from complex were observed with 20 mg of canthaxanthin and 400 mg of V-amylose. DLS analysis showed that the hydrodynamic diameter of the particles was reduced by ultrasonication to 244 nm. TEM analysis also demonstrated that particles resemble spherical or oval shape after ultrasonication. The powder dispersion remained stable after 1 month. XRD diffractograms represented the amorph structure of complex despite the crystalline structure of pure canthaxanthin, and DSC curves showed the same melting point of complex and V-amylose, both showing the change of canthaxanthin structure to amorph in the encapsulation process, indicating the complete entrapment of canthaxanthin in V-amylose helices. Oxidation stability analysis of the complex revealed an increase in the oxidation resistance of canthaxanthin. Analysis of both ABTS and DPPH radical scavenging activity by the complex showed that this feature was concentration dependent. According to the obtained results, this method is a promising way to be utilized for expanding the use of canthaxanthin in food and pharmaceutical applications with improved solubility and bioavailability. [ABSTRACT FROM AUTHOR]

A bacterial strain was isolated from an oil-contaminated site and on its' further characterization, exhibited the potential of synthesising metabolites and the ability to degrade crude oil. Its' morphological, biochemical and 16S rRNA analysis suggested that the bacterium belongs to Dietzia maris AURCCBT01. This strain rapidly grew in the medium supplemented with n-alkanes C14, C18, C20, C28 and C32 utilizing them as a sole carbon source and produced a maximum canthaxanthin pigment of 971.37 µg/L in the n-C14 supplemented medium and produced the lowest pigment yield of 389.48 µg/L in the n-C-32 supplemented medium. Moreover, the strain effectively degraded 91.87% of crude oil in 7 days. The emulsification activity of the strain was 25% with the highest cell surface hydrophobicity (70.26%) and it showed a decrease in surface tension, indicating that the biosurfactant production lowers the surface tension. This is the first report on the characterization of the strain, Dietzia maris AURCCBT01 and its' novelty of alkane degradation and simultaneous production of canthaxanthin pigment. [ABSTRACT FROM AUTHOR]

In this study, a novel route for the total synthesis of canthaxanthin is described. The synthesis is firstly based on an epoxidation of α-ionone with metachloroperbenzoic acid to afford the epoxide, followed by conversion of the epoxide to 3-hydroxyl-β-ionone in the presence of sodium methoxide. Next, 3-hydroxyl-C14-aldehyde was obtained by a Darzens condensation with 4-hydroxyl-β-ionone and methyl chloroacetate, which can be converted to 3-hydroxyl-C15-phophonate via a Wittig–Horner condensation with tetraethyl methylenebisphosphonate. Then, a Wittig–Horner condensation with 3-hydroxyl-C15-phosphonate and C10-trienedial resulted in 4,4′-dihydroxyl-β-carotene, followed by an oxidation afforded the target product canthaxanthin. The overall yield of this route is 37% from α-ionone. The synthetic steps are easily operated and are practical for the large-scale production. [ABSTRACT FROM AUTHOR]

The remarkable drought-resistance of the terrestrial cyanobacterium Nostoc flagelliforme (N. flagelliforme) has attracted attention for many years. In this study, we purified a group of red proteins that accumulate in dried field samples of N. flagelliforme. These red proteins contain canthaxanthin as the bound chromophore. Native-PAGE analysis revealed that the purified red proteins resolved into six visible red bands and were composed of four helical carotenoid proteins (HCPs), HCP1, HCP2, HCP3, and HCP6 (homologs to the N-terminal domain of the orange carotenoid protein (OCP)). Seven genes encode homologs of the OCP in the genome of N. flagelliforme: two full-length ocp genes (ocpx1 and ocpx2), four N-terminal domain hcp genes (hcp1, hcp2, hcp3, and hcp6), and one C-terminal domain ccp gene. The expression levels of hcp1, hcp2, and hcp6 were highly dependent on the water status of field N. flagelliforme samples, being downregulated during rehydration and upregulated during subsequent dehydration. Transcripts of ocpx2 were dominant in the dried field samples, which we confirmed by detecting the presence of OCPx2-derived peptides in the purified red proteins. The results shed light on the relationship between carotenoid-binding proteins and the desiccation resistance of terrestrial cyanobacteria, and the physiological functions of carotenoid-binding protein complexes in relation to desiccation are discussed. [ABSTRACT FROM AUTHOR]

Light-driven H+, Cl− and Na+ rhodopsin pumps all use a covalently bound retinal molecule to capture light energy. Some H+-pumping rhodopsins (xanthorhodopsins; XRs) additionally contain a carotenoid antenna for light absorption. Comparison of the available primary and tertiary structures of rhodopsins pinpointed a single Thr residue (Thr216) that presumably prevents carotenoid binding to Na+-pumping rhodopsins (NaRs). We replaced this residue in Dokdonia sp. PRO95 NaR with Gly, which is found in the corresponding position in XRs, and produced a variant rhodopsin in a ketocarotenoid-synthesising Escherichia coli strain. Unlike wild-type NaR, the isolated variant protein contained the tightly bound carotenoids canthaxanthin and echinenone. These carotenoids were visible in the absorption, circular dichroism and fluorescence excitation spectra of the Thr216Gly-substituted NaR, which indicates their function as a light-harvesting antenna. The amino acid substitution and the bound carotenoids did not affect the NaR photocycle. Our findings suggest that the antenna function was recently lost during NaR evolution but can be easily restored by site-directed mutagenesis. [ABSTRACT FROM AUTHOR]

Unlike the wild type, the mutant Aspergillus carbonarius synthesized a yellow pigment, partially saturated canthaxanthin (PSC) when the growth medium acidified to low pH. Since the pigment found pharmaceutical applications, the possible mechanism involved in its ability to grow at extreme acidic conditions is described. To understand the mutation in the pathway, specific inhibitors affecting carotenoid biosynthesis were used in the medium and PSC synthesis and cell integrity were studied. Results suggested that the possible occurrence of mutation in the isoprenoid pathway for higher production of carotenoid as well as ergosterol caused the mutant to grow in extremely acidic conditions. The results also suggested that the flow of carbon for sterol biosynthesis and that of carotenoids are dependent. The deposition of carotenoids and ergosterol in the cell membrane causing the cells to maintain pH homeostasis under the acidic growth conditions is of significant importance. In A. carbonarius, understanding the cause of stress induced PSC accumulation is essential for efficient expression and production of the pharmaceutically significant carotenoid and this will further facilitate research into the role of carotenoids in stress tolerance of other filamentous fungi. [ABSTRACT FROM AUTHOR]

Fairy shrimp is known as a nutritional food for fish and crustaceans in aquaculture. In most hatcheries, the microalga Chlorella sp. appears to be the most common, suitable, and nutritious food to feed fairy shrimp. In this study, we attempted to determine other alternative algal diets for cultivation of fairy shrimp Branchinella thailandensis. Seven experimental diets including three treatments of dried Spirulina sp. at 0.75 ( S1), 1.5 ( S2), and 3.0 mg dry weight individual ( S3); three treatments of Chlorococcum humicola at 5 × 10 ( Ch1), 1 × 10 ( Ch2), and 2 × 10 cells mL ( Ch3); and a control diet ( Chlorella vulgaris at 1 × 10 cells mL) were fed to 5-day-old shrimp for 15 days. Evaluation of growth performance, egg production, survival percentage, and nutritional and carotenoid content of the experimental fairy shrimp revealed that Ch3 is the most suitable algal diet. Our results suggest that C. humicola is the best alternative food source for the cultivation of B. thailandensis. In addition, dried Spirulina powder is also a good choice when live algae are not available and can be used as an alternative feed in fairy shrimp cultures. [ABSTRACT FROM AUTHOR]

A 6-week experiment was carried out to evaluate the effects of diets containing 0, 0.004, 0.008, 0.012 and 0.016 % synthetic canthaxanthin on growth, feed utilization and skin pigmentation of parrot cichlid ( Amphilophus citrinellus × Paraneetroplus synspilus). Three hundred and sixty fish with initial body weights of 18.0 ± 1.6 g were randomly stocked equally into 15 glass aquaria (each 80 × 40 × 50 cm) to form five triplicate groups. Fish were fed one of five diets daily at 2 % of their total body weight. At the end of the experiment, all fish were harvested and weighed to calculate growth parameters. After weighing, randomly selected two fish from each aquarium were used to assess the body colour using a colorimeter. Results indicated that dietary canthaxanthin supplementation had no effect on growth, feed conversion ratio, ingestion rate and condition factor of parrot cichlid. The degree of pigmentation in skin of parrot cichlid increased significantly ( P < 0.05) with increasing inclusion of canthaxanthin up to 0.012 % in the diet. Canthaxanthin inclusion over that level did not lead to increase more redness, yellowness, hue and chroma of parrot cichlid skin. Diet containing more than 0.012 % canthaxanthin even decreased redness of fish skin (16 % decreased) compared to diet containing 0.012 % canthaxanthin (18.67 ± 0.32). In the present study, observations based on the effects of various canthaxanthin levels on colour parameters suggest that the diet containing a 0.012 % canthaxanthin may be considered as the best level of canthaxanthin supplementation for best skin colouration of parrot cichlid. [ABSTRACT FROM AUTHOR]

The strain bacterium Dietzia natronolimnaea has propounded as a source for biological production of canthaxanthin. Because of sensitivity of this pigment, examine on its stability is important. In this study, stability of encapsulated canthaxanthin from D. natronolimnaea HS-1 using soluble soybean polysaccharide (SSPS), gum acacia (GA), and maltodextrin (MD) as wall materials was investigated at 4, 25, and 45 °C in light and dark conditions during 4 months of storage. It was shown that the type of walls influenced the size of emulsion droplets; spray dried particles, microencapsulation efficiency (ME), and retention of canthaxanthin in microcapsules. SSPS and MD produced the smallest and the biggest emulsion droplets and spray dried particles, respectively. Microcapsules made with SSPS resulted in better ME and higher stability for canthaxanthin. Samples were degraded in all conditions, especially in light and 45 °C. Degradation of microencapsulated canthaxanthin with SSPS and GA proceeded more slowly than did with MD. Regardless of the type of wall materials, total canthaxanthin contents of the microencapsulated products decreased by an increase in time or temperature. Also, samples exposed to light indicated less stability at 4 and 25 °C when compared to the storage at dark conditions. According to the results of this study, SSPS can be considered as potential wall material for the encapsulation of carotenoids. [ABSTRACT FROM AUTHOR]

Canthaxanthin crystal and three isomeric samples generated by different processes (solvent dissolving, iodine catalysis, and melting) were selected to study the chemical changes during different isomerization processing. No sharp difference could be found when the nuclear magnetic resonance spectra of canthaxanthin crystal and canthaxanthin obtained by solvent dissolving and iodine catalysis were compared, suggesting that only isomerization occurred in those isomeric samples. However, the content of unsaturated hydrogen decreased during the melting of canthaxanthin, and the measurements of gel permeation chromatography and UV/Vis spectroscopy showed that the canthaxanthin melt contained few compositions of polymer and degradation products. A high-performance liquid chromatography (HPLC) analysis system consisting of a C column and an elution system of methanol/methyl tert-butyl ether/water/dichloromethane (60:25:12:3, v/ v/ v/ v) was employed to identify the compositions detected in HPLC. Using the combination of HPLC-diode array detector and HPLC-atmospheric pressure chemical ionization-mass spectrometry, ten isomers and four epoxides of canthaxanthin were successfully isolated. The isomer compositions were identified as 9,13′-di- cis-, 13,15-di- cis-, 9,15-di- cis-, 15- cis-, 13- cis-, 9,13-di- cis-, all- trans-, 11- cis-, 7- cis-, and 9- cis-canthaxanthin. The chromatographic purity and content of canthaxanthin sample also can be determined based on the C-HPLC method. [ABSTRACT FROM AUTHOR]

Canthaxanthin is a natural diketo derivative of β-carotene primarily used by the food and feed industries. Mucor circinelloides is a β-carotene-accumulating zygomycete fungus and one of the model organisms to study the carotenoid biosynthesis in fungi. In this study, the β-carotene ketolase gene ( crtW) of the marine bacterium Paracoccus sp. N81106 fused with fungal promoter and terminator regions was integrated into the M. circinelloides genome to construct stable canthaxanthin-producing strains. Different transformation methods including polyethylene glycol-mediated transformation with linear DNA fragments, restriction enzyme-mediated integration and Agrobacterium tumefaciens-mediated transformation were tested to integrate the crtW gene into the Mucor genome. Mitotic stability, site of integration and copy number of the transferred genes were analysed in the transformants, and several stable strains containing the crtW gene in high copy number were isolated. Carotenoid composition of selected transformants and effect of culturing conditions, such as temperature, carbon sources and application of certain additives in the culturing media, on their carotenoid content were analysed. Canthaxanthin-producing transformants were able to survive at higher growth temperature than the untransformed strain, maybe due to the effect of canthaxanthin on the membrane fluidity and integrity. With the application of glucose, trehalose, dihydroxyacetone and l-aspartic acid as sole carbon sources in minimal medium, the crtW-expressing M. circinelloides strain, MS12+pCA8lf/1, produced more than 200 μg/g (dry mass) of canthaxanthin. [ABSTRACT FROM AUTHOR]

In the genome of Nostoc punctiforme PCC 73102, three functional β-carotene ketolase genes exist, one of the crtO and two of the crtW type. They were all expressed and their corresponding enzymes were functional inserting 4-keto groups into β-carotene as shown by functional pathway complementation in Escherichia coli. They all synthesized canthaxanthin but with different efficiencies. Canthaxanthin is the photoprotective carotenoid of N. punctiforme PCC 73102. Under high-light stress, its synthesis was enhanced. This was caused by up-regulation of the transcripts of two genes in combination. The first crtB-encoding phytoene synthase is the gate way enzyme of carotenogenesis resulting in an increased inflow into the pathway. The second was the ketolase gene crtW148 which in high light takes over β-carotene conversion into canthaxanthin from the other ketolases. The other ketolases were down-regulated under high-light conditions. CrtW148 was also exclusively responsible for the last step in 4-keto-myxoxanthophyll synthesis. [ABSTRACT FROM AUTHOR]

Today microalgae represent a viable alternative source for high-value products. The specie Chlorella protothecoides ( Cp), heterotrophically grown, has been widely studied and provides a high amount of lutein and fatty acids (FA) and has a good profile for biodiesel production. This work studies carotenoid and FA production by autotrophic grown Cp. Cp was grown until the medium's nitrogen was depleted, then diluted in NaCl solution, resulting in nutritional, luminosity, and salinity stresses. Different NaCl concentrations were tested (10, 20, 30 g/L) at two different dilutions. After dilution, a color shifting from green to orange-red was noticed, showing carotenoid production. The best production of both carotenoids and FA was attained with a 20 g/L NaCl solution. The total carotenoid content was 0.8 % w/ w (canthaxanthin (23.3 %), echinenone (14.7 %), free astaxanthin (7.1 %), and lutein/zeaxanthin (4.1 %)). Furthermore, the total lipid content reached 43.4 % w/ w, with a FA composition of C18:1 (33.64 %), C16:0 (23.30 %), C18:2 (11.53 %), and less than 12 % of C18:3, which is needed to fulfill the biodiesel quality specifications (EN 14214). [ABSTRACT FROM AUTHOR]

Dietzia maris NIT-D, a canthaxanthin producer, was isolated during routine screening of pigment-producing bacteria. Response surface methodology was applied for statistical designing of process parameters for biomass and canthaxanthin production. The effects of four process parameters (considered as independent variables), namely temperature (10-30 °C), pH (4.75-5.75), shaker speed (75-135 rpm) and percentage inoculum (0.5-2.5 %) on the biomass and canthaxanthin yield (considered as dependent variables) were studied. As much as 122 mg L of canthaxanthin was obtained when Dietzia maris NIT-D was incubated for 120 h at 25 °C and 120 rpm, initial pH and percentage inoculum being 5.5 and 2 % respectively. The pigment yield is the highest reported till date, with Dietzia maris as the test organism. The maximum biomass yield was 7.39 g L under optimized process parameters. The predicted values were also verified by validation experiments in 5-day fermentation. Different mathematical models were used to describe growth and production, considering the effect of glucose in batch mode. The kinetic constants were calculated by fitting the experimental data to the models. Cell growth was inhibited beyond a glucose concentration of 15 g L. Andrews' model gave the best fit with a R value of 0.9993. During the exponential growth phase, the specific growth rate was found to remain fairly constant with respect to time. There was no inhibitory effect due to intracellular product accumulation for all concentrations of glucose. This observation is the first of its kind, as previous studies have reported that increasing accumulation of intracellular carotenoid exerts greater degree of inhibition on growth. [ABSTRACT FROM AUTHOR]

Carotenoids, such as lycopene, β-carotene, zeaxanthin, canthaxanthin and astaxanthin have many benefits for human health. In addition to the functional role of carotenoids as vitamin A precursors, adequate consumption of carotenoids prevents the development of a variety of serious diseases. Biosynthesis of carotenoids is a complex process and it starts with the common isoprene precursors. Condensation of these precursors and subsequent modifications, by introducing hydroxyl- and keto-groups, leads to the generation of diversified carotenoid structures. To improve carotenoid production, metabolic engineering has been explored in bacteria, yeast, and algae. The success of the pathway engineering effort depends on the host metabolism, specific enzymes used, the enzyme expression levels, and the strategies employed. Despite the difficulty of pathway engineering for carotenoid production, great progress has been made over the past decade. We review metabolic engineering approaches used in a variety of microbial hosts for carotenoid biosynthesis. These advances will greatly expedite our efforts to bring the health benefits of carotenoids and other nutritional compounds to our diet. [ABSTRACT FROM AUTHOR]

Microencapsulation of canthaxanthin produced by Dietzia natronolimnaea HS-1 using soluble soybean polysaccharide (SSPS) as a wall material by spray drying method was studied. The SSPS showed very good ability for microencapsulation of canthaxanthin due to its emulsifying properties. The effects of the ratios of core to wall on characteristics of microcapsules were investigated at ratios of 0.25, 0.50, 0.75, and 1.00. The best ratio of core to wall was 0.25 because the microcapsules prepared with this ratio had the smallest size in droplets (0.78 μm) and microcapsules (7.94 μm), also they had the highest microencapsulation efficiency (90.1%) and the lowest losing during process (10.3%). The stability of microcapsules was examined at 25°C in light and dark during 16 weeks of storage. The degradation of canthaxanthin was more retarded by microencapsulation and greater canthaxanthin stability was observed in dark than light condition. The results showed the oxidation was more suppressed for the microcapsules prepared from the emulsion having smaller droplets. [ABSTRACT FROM AUTHOR]

The present investigation aimed to compare fetal calf serum (FCS) and Tween 40 with the commonly employed tetrahydrofuran (THF) with respect to cytotoxicity, stability of the solubilized carotenoids, and uptake and accumulation of the xanthophylls astaxanthin (AX) and canthaxanthin (CX) in cultured human liver cells (HepG2). Incubation of HepG2 cells for 24 h with THF (≥1.25%) or FCS (≥11.25%) with or without AX (≥25 μmol/L) or CX (≥25 μmol/L) did not affect cell viability. Tween 40 (0.25-1.25% in medium) reduced cell viability by 75-99%. The stabilities of AX and CX in cell-free RPMI 1640 medium for ≤24 h were higher when delivered with THF instead of FCS. The dose- and time-dependent accumulations of AX and CX (1-10 μmol/L) in HepG2 cells were higher when carotenoids were delivered with FCS compared to THF. In conclusion, FCS and THF, but not Tween 40, were suitable solvent systems for the delivery of AX and CX to HepG2 cells. In our experiments FCS was superior with regard to the uptake and accumulation of both carotenoids. [ABSTRACT FROM AUTHOR]

for many deep-sea animals, the red colouration of the two amphipods Eurythenes gryllus and Anonyx sp. has an important function providing camouflage, as the attenuation of the red wavelengths in seawater is higher than other colours within the visible range. Variation in colouration between different stages of colour intensity (related to size) is evident in both species. The red colour is caused by carotenoids, and the carotenoid composition was identified and quantified using spectral optical density signatures, high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS). The carotenoid astaxanthin was identified as the major carotenoid in both amphipods, both in pure and in esterified forms. In addition, minor amounts of lutein-like, canthaxanthin-like and several unidentified carotenoids were found in E. gryllus, while diatoxanthin, β,β-carotene and canthaxanthin-like carotenoids were detected in Anonyx sp. Generally, both species displayed an increase in the amount of carotenoids as a function of colour intensity and size. Shifts in λ in the OD (Optical density; dimensionless, acronym absorbance) spectra were evident in both species between the different colour stages in both the in vivo and the in vitro material, probably caused by changes in pigment composition. Similar shifts in λ were observed between the in vivo and in vitro pigment raw extracts in general, most likely caused by pigment-binding proteins. The differences in pigment composition and wavelength shifts suggest large intra- and inter-specific differences between the two species. Probable reasons for changes in pigment composition could be related to diet, season, moulting patterns, metabolic pathways and reproduction. [ABSTRACT FROM AUTHOR]

Abstract  The objective of this study was to determine the possibility of using Mixolab® to predict the cookie baking quality of different wheat flours. Mixolab data was also compared with various flour quality characteristics. There were significant correlations (P  T value was negatively correlated with Mixolab C3, C4 and C5 values. The cookie diameter gave highly significant correlations with protein content, Zeleny sedimentation value and damaged starch content. Mixolab C3 and C4 values were highly correlated (P r = 0.556) was determined between the cookie diameter and C1–C2 value which is an indication of protein quality. The dependence of cookie diameter and spread ratio on Mixolab C3 value, damaged starch content and Zeleny sedimentation value were analyzed with multiple regression analysis and high multiple correlation coefficients were found between these parameters (r = 0.948 and 0.861, respectively). [ABSTRACT FROM AUTHOR]

Abstract  Lutein, zeaxanthin, and β-cryptoxanthin are xanthophyll pigments that own conjugated double bonds; some factors can convert (all-E)-xanthophylls to their (Z)-isomers such as high temperature, illumination, and oxidants. In the present work, the Fe(II)-induced isomerization of (all-E)-lutein, (all-E)-zeaxanthin, and (all-E)-β-cryptoxanthin in acetone were analyzed by HPLC coupled with DAD and APcI-MS. The three (all-E)-xanthophylls were baseline separated and their (Z)-isomers were identified by the chromatographic retention, UV/vis spectra and positive mass spectrometry with reference values reported in the literature. The results showed that Fe(II) exhibited a rapidly isomerization induction of (all-E)-xanthophylls to their (Z)-isomers exceeding a 8/1 mass ratio of Fe(II)/pigments. The (13-Z)-lutein and (13′-Z)-lutein were identified as the major (Z)-isomers of (all-E)-lutein treated with FeSO4·7H2O, and (13-Z)-zeaxanthin was identified as the major isomerization product of (all-E)-zeaxanthin. Furthermore, a type of (Z)-β-cryptoxanthin was also detected. Increasing either mass ratio of Fe(II)/pigments or the incubation time of FeSO4·7H2O and (all-E)-xanthophylls may affect on the stabilities of (Z)-isomers derived from (all-E)-xanthophylls. [ABSTRACT FROM AUTHOR]

A mutant Aspergillus carbonarius selected for temperature tolerance after UV treatment, when grown in shake flasks, produced mycelia bearing yellow pigment. Since the mutant was affected in sterol biosynthetic pathway, the pigment was apparently produced to maintain membrane fluidity and rigidity for growth sustenance in low-pH culture broth. Nuclear magnetic resonance analyses characterizing the pigment as a partially saturated canthaxanthin, containing β-ionone end rings, suggested its application as a retinoid. When tested for this property in retinoic acid receptor expressing prostate cancer cell line, LNCaP, the fungal partially saturated canthaxanthin induced apoptosis. Low apoptosis percentage in DU145 prostrate cancer cells that does not express functional retinoic acid receptor-β (RAR-β) suggested binding specificity of the partially saturated canthaxanthin for RAR-β. [ABSTRACT FROM AUTHOR]

Abstract  The objective of this study was to determine the possibility of using Mixolab® to predict the cookie baking quality of different wheat flours. Mixolab data was also compared with various flour quality characteristics. There were significant correlations (P  T value was negatively correlated with Mixolab C3, C4 and C5 values. The cookie diameter gave highly significant correlations with protein content, Zeleny sedimentation value and damaged starch content. Mixolab C3 and C4 values were highly correlated (P r = 0.556) was determined between the cookie diameter and C1–C2 value which is an indication of protein quality. The dependence of cookie diameter and spread ratio on Mixolab C3 value, damaged starch content and Zeleny sedimentation value were analyzed with multiple regression analysis and high multiple correlation coefficients were found between these parameters (r = 0.948 and 0.861, respectively). [ABSTRACT FROM AUTHOR]

Corallium rubrum is the most famous and precious coral due to the intense characteristic red colour of its skeleton. We have determined the presence of carotenoids in natural samples of C. rubrum from Marseille, Riou, and investigated their chemical composition. Analysis was performed both on soft tissues and hard tissues including spicules and skeleton. Since hard tissues are made of a mineral fraction and an organic fraction obtained after demineralization, extraction was performed both with and without demineralization by EDTA. The extracts were analyzed by complementary methods of TLC, HPLC/DAD and HPLC/MS. The components were separated by RP-18 chromatography column using acetonitrile/methanol for HPLC/DAD and acetonitrile/water gradient for HPLC/MS analysis. Our results give the first evidence of the presence of canthaxanthin, 4,4′-diketo-β-carotene, as the major carotenoid in all samples. Spicules exhibited higher content in carotenoids than skeleton. Demineralization treatment improved the efficiency of carotenoid extraction by an average factor of 5 and showed that organic matrix contains canthaxanthin. [ABSTRACT FROM AUTHOR]

β-Carotene hydroxylase (CrtZ) is one of rate-limiting enzymes for astaxanthin production. A complementation analysis was conducted using Escherichia coli transformants to compare the catalytic efficiency of bacterial CrtZ from Brevundimonas sp. SD212, Paracoccus sp. PC1 (formerly known as Alcaligenes sp. PC-1), Paracoccus sp. N81106 ( Agrobacterium aurantiacum), Pantoea ananatis ( Erwinia uredovora 20D3), marine bacterium P99-3, and P450 monooxygenase (CYP175A1) from Thermus thermophilus HB27. Each crtZ or CYP175A1 gene was expressed in E. coli transformants synthesizing canthaxanthin and β-carotene due to the respective presence of plasmids pAC-Cantha and pACCAR16ΔcrtX. The carotenoids that accumulated in the resulting recombinant E. coli cells were examined by chromatographic and spectroscopic analyses. E. coli carrying Brevundimonas sp. SD212 crtZ showed the highest astaxanthin production efficiency among the transformants examined, while there was no significant difference in the catalytic efficiency for conversion from β-carotene to zeaxanthin. Recombinant E. coli expressing the CYP175A1 gene, in addition to the genes for canthaxanthin synthesis, surprisingly accumulated adonirubin (phoenicoxanthin) as the main product, although the other recombinant E. coli did not accumulate any adonirubin. The present results suggest that the Brevundimonas sp. SD212 crtZ and T. thermophilus HB27 CYP175A1 genes could, respectively, be used for the efficient production of astaxanthin and adonirubin in heterologous hosts. [ABSTRACT FROM AUTHOR]

Commercial interest in the use of natural pigments isolated from microorganisms has increased in recent years; hence, molecules belonging to the polyisoprenoid group (i.e. β-carotene, astaxanthin, and canthaxanthin) have been the focus of much attention. The bacterium Gordonia jacobaea readily synthesizes and accumulates large amounts of canthaxanthin (β-β′-carotene-4,4′-dione), which is widely used in the food and cosmetics industries. In the present work, the effects of different low-cost raw materials on fermentation and canthaxanthin accumulation by a hyperpigmented strain of G. jacobaea were studied. Canthaxanthin production and peak levels of accumulation varied according to the different media used. [Int Microbiol 2005; 8(1):55-58] [ABSTRACT FROM AUTHOR]

For the heterologous synthesis of keto-carotenoids such as astaxanthin, two carotenoid ketolase genes crtW38 and crtW148, were cloned from the cyanobacterium, Nostoc punctiforme PCC 73102 and functionally characterized. Upon expression in Escherichia coli, both genes mediated the conversion of β-carotene to canthaxanthin. However in a zeaxanthin-producing E. coli, only the gene product of crtW148 introduced 4-keto groups into the 3,3′-dihydroxy carotenoid zeaxanthin yielding astaxanthin. The gene product of crtW38 was unable to catalyze this reaction. Both ketolases differ in their interaction with a hydroxylase in the biosynthetic pathway from β-carotene to astaxanthin. [ABSTRACT FROM AUTHOR]

Larval Atlantic halibut fed Artemia has previously been shown to contain lower levels of Vitamin A compared to larvae fed zooplankton. The two types of live prey contain small or no amounts of vitamin A, but high levels of carotenoids that can be converted to vitamin A in other fish species. The purpose of this study was to investigate the ability of Atlantic halibut juveniles to convert β-carotene, astaxanthin and canthaxanthin to vitamin A. Three levels of each carotenoid and retinyl acetate were fed to Atlantic halibut juveniles for 60 days. A vitamin A and carotenoid deficient diet was fed in triplicate as control. A HPLC method modified from Nöll (1996) and validated for fish matrix was used to quantify both all- trans-retinol and 3,4-didehydro retinol. By comparing regression coefficients we observed that the increasing levels of carotenoids in the diets were reflected in increasing levels of vitamin A in both whole fish and liver samples. All carotenoids were converted to vitamin A, but to different degrees. Retinyl acetate and β-carotene resulted in whole fish vitamin A levels significantly higher than canthaxanthin and astaxanthin. 3,4-didehydro retinol was not detected when the overall level of all- trans-retinol was low. When 3,4-didehydro retinol appeared, it was always in lower levels than all- trans-retinol. [ABSTRACT FROM AUTHOR]

The production of carotenoids from Haloferax alexandrinus strain TMT was investigated at various concentrations of NaCl (10–25%) in culture media under non-aseptic conditions. PCR and dot blot hybridization assays were employed to monitor the growth of Hfx. alexandrinus in the culture under aseptic and non-aseptic conditions. The amplified PCR products of 16S rDNA from Hfx. alexandrinus grown under aseptic conditions were used as specific probes, which bound with amplified PCR products of 16S rDNA dots from both aseptic and non-aseptic conditions (20–25% NaCl). The results indicated that contamination of the culture was precluded at high NaCl concentrations (20–25%). Therefore, it is not necessary to perform asepsis during the biotechnological processes of carotenoid production by Hfx. alexandrinus. A 1-l-scale cultivation of the cells in flask cultures under non-aseptic conditions produced 3.12±0.5 g dry weight, 6.34±2.5 mg total carotenoids and 2,156.67±0.1 µg canthaxanthin. Further experiments in a batch fermenter, under non-aseptic conditions, also demonstrated increases in the biomass concentration and carotenoid production. When grown in a standard growth medium at 25% NaCl, the cells of Hfx. alexandrinus lysed spontaneously in fresh water and hence carotenoids could be extracted directly from the cells without any mechanical disintegration. These results demonstrate the feasibility and simplicity of commercial production of carotenoids using Hfx. alexandrinus. [ABSTRACT FROM AUTHOR]

The microalga Haematococcus pluvialis was cultured with NaNO3 from 0 to 1 g l-1 and optimal growth was obtained at 0.15 g l-1. Sodium acetate and malonate (from 0 to 2% w/v) enhanced the accumulation of astaxanthin three and five times higher, respectively, than in autotrophic control cultures. However, high concentration of those compounds strongly inhibited growth. The ratio chlorophyll a/total carotenoids was a good indicator of the extent of nitrogen deficiency in the cells. [ABSTRACT FROM AUTHOR]

The vitamin-A status of 107 patient with psoriasis and 37 healthy controls was investigated. The mean serum level of retinol-binding protein (RBP) was normal in the 79 patients with chronic plaque psoriasis covering 25% or less of the skin surface. In the 28 patients with more extensive plaque lesions or pustular/ erythrodermic psoriasis, the mean serum RBP level was significantly lower than in the controls ( P<0.05). The cutaneous concentrations of retinol (vitamin A), dehydroretinol (vitamin A) and carotenoids were measured in extracts of saponified shave-biopsy specimens of uninvolved and involved skin from 33 patients with plaque psoriasis. Their retinol values did not differ significantly from those found in control skin (mean, 252 ng/g), whereas the carotenoid levels in both uninvolved and involved skin were 25%-50% lower. In contrast, the dehydroretinol concentration was higher in the patients' involved skin (mean, 237 ng/g) than in their uninvolved skin (94 ng/g) and healthy control skin (70 ng/g; P<0.01). Although the origin of increased dehydroretinol levels in involved psoriatic skin is unknown, similar increments were observed in control epidermis in which proliferation had been induced by tape stripping. In 7 patients treated with oral etretinate (aromatic retinoid) for 2-3 weeks, the median retinol and dehydroretinol levels in involved skin increased by 107% and 212%, respectively; the vitamin-A concentrations in uninvolved skin did not change significantly. Oral treatment with β-carotene/canthaxanthin raised the median carotenoid levels in uninvolved and involved skin by 170% and 610%, respectively, without significantly affecting the vitamin-A composition. [ABSTRACT FROM AUTHOR]

We succeeded in isolating a novel cDNA involved in astaxanthin biosynthesis from the green alga Haematococcus pluvialis, by an expression cloning method using an Escherichia coli transformant as a host that synthesizes β-carotene due to the Erwinia uredovora carotenoid biosynthesis genes. The cloned cDNA was shown to encode a novel enzyme, β-carotene ketolase (β-carotene oxygenase), which converted β-carotene to canthaxanthin via echinenone, through chromatographic and spectroscopic analysis of the pigments accumulated in an E. coli transformant. This indicates that the encoded enzyme is responsible for the direct conversion of methylene to keto groups, a mechanism that usually requires two different enzymatic reactions proceeding via a hydroxy intermediate. Northern blot analysis showed that the mRNA was synthesized only in the cyst cells of H. pluvialis. E. coli carrying the H. pluvialis cDNA and the E. uredovora genes required for zeaxanthin biosynthesis was also found to synthesize astaxanthin (3S, 3′S), which was identified after purification by a variety of spectroscopic methods. [ABSTRACT FROM AUTHOR]

Erythropoietic protoporphyria (EPP), a recently described form of porphyria, often remains unrecognized. We report the case of a 7-year-old girl admitted for investigation of photosensitivity since the age of 18 months without any significant objective cutaneous lesions. Clinical features, quantitative determinations of porphyrins in blood, urine and stools, ferrochelatase activity and cutaneous histopathology helped to confirm the diagnosis of EPP. A familial study was also performed. The clinical, laboratory and genetic characteristics of EPP are reviewed. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Determination of canthaxanthin in the red coral (Corallium rubrum) from Marseille by HPLC combined with UV and MS detection," by Jelena Cvejic, Sylvie Tambutte, Severine Lotto, Momir Mikov, Ivan Slacanin and Denis Allemand in the 2007 issue.

A response by Jelena Cvejic, Sylvie Tambutte, Severine Lotto, Momir Mikov, Ivan Slacanin and Denis Allemand to a letter to the editor about their article "Determination of canthaxanthin in the red coral (Corallium rubrum) from Marseille by HPLC combined with UV and MS detection" in the 2007 issue is presented.