Methoxyspheroidene and methoxyspheroidenone,two carotenoids from Rhodopseudomonas spheroides

Two new carotenoids isolated from Rhodopseudomonas spheroides (Rhodospirillaceae) have been identified as methoxyspheroidene (1,1′-dimethoxy-3,4-didehydro-1,2,1′,2′,7$\text{,}\text{?}$8′-hexahydro-ψ,ψ-carotene) obtained from anaerobic cultures and methoxyspheroidenone (1,1′-dimethoxy-3,4-didehydro-1,2,1′,2′,7′,8′-hexahydro-ψ,ψ-caroten-2-one) recovered from aerobic cultures.     

Composition and content of carotenoids in body of the Black sea gastropod Rapana venosa (Valenviennes, 1846)

The composition and content of carotenoids were studied in the body of Black sea gastropod Rapana venosa. The methods of thin layer and high performance liquid chromatography, mass-spectra and the spectra in UV-VIS diapason were used for isolation and identification of compounds belonging to this group. 84–87% of carotenoids were identified. The main part of them is presented by mytiloxanthin—28–30%. Other—pectenolon, diatoxanthin, alloxanthin—composed 10–15% of total content, with exception of β-carotene—3–4%. The fraction containing complex esters of pectenolon, diatoxanthin, alloxanthin and mytiloxanthin was also isolated. It composes 17–20% of the pigments of carotene row. The minor components were not determined. Study discusses the pathways of carotenoid metabolic transformation in the R. venosa tissues studying trophic system “mollusc-filter—mollusc-predator” on examples of Mytilus galloprovincialis and R. venosa.     

The qualitative composition of carotenoids and their seasonal dynamics in tissues of the bivalve <Emphasis Type="Italic">Anadara kagoshimensis</Emphasis> (Tokunaga, 1906)

A total of six carotenoids, viz., β-carotene, pectenol A, pectenolone (trans- and cis-isomers), zeaxanthin, diatoxanthin, and alloxanthin, as well as esters of alloand diatoxanthin, have been detected in total carotenoid extracts from the tissues of the bivalve Anadara kagoshimensis (Tokunaga, 1906) using the methods of thin-layer chromatography, high-performance liquid chromatography, mass spectrometry, UV-VIS spectroscopy, and characteristic reactions for the identification of chemical groups. The major group (over 90% of the total carotenoids) is comprised of alloxanthin, pectenolone, and allo- and diatoxanthin esters. Tissues of A. kagoshimensis are typically characterized by cyclic variations in the level of carotenoids over the period from winter to summer, with the maxima in February and June and the minimum in April. The largest contribution to the seasonal carotenoid dynamics is made by the major group of pigments (R ² = 0.75–0.99), which depends on the pattern of succession of diatomic microalgae during the annual cycle. The pathways of metabolic transformation of the carotenoids in tissues of this bivalve are discussed.     

Carotenoids of Anacystis nidulans,structures of caloxanthin and nostoxanthin

Reinvestigation of the carotenoids of Anacystis nidulans has confirmed the occurrence of β,β-carotene (β-carotene), β,β-caroten-3-ol (cryptoxanthin), β,β-carotene-3,3′-diol (zeaxanthin) and 2R,3R,3′R-β,β-carotene-2,3,3′-triol (absolute configuration assigned in the present work). In addition the previously unknown 2R,3R,2′R,3′R-β,β-carotene-2,3,2′,3′-tetrol has been isolated. The triol and the tetrol are considered identical with caloxanthin and nostoxanthin, respectively, for which allenic structures have been suggested by others. The chirality of these compounds followed from CD and ¹H NMR considerations.     

Qualitative composition of carotenoids, catalase and superoxide dismutase activities in tissues of the bivalve mollusc Anadara inaequivalvis (Bruguiere, 1789)

Using high performance liquid chromatography, UV-VIS spectra and mass-spectra (FAB MS), 7 carotenoid species were identified in tissues of the bivalve mollusc Anadara inaequivalvis (Bruguiere, 1789): trans- and cis-pectenolon, alloxanthin, pectenol A, β-carotene, zeaxanthin, and diatoxanthin. Their quantitative ratio in hepatopancreas, gills and foot of animals were determined. A negative correlation (R ² is about 0.9) was revealed between tissues content of a series of carotenoids (trans- and cis-pectenolon, zeaxanthin, alloxanthin, and diatoxanthin) and activity of antioxidant enzymes (catalase and superoxide dismutase). The existence of competitive interrelations between these molecular systems is proposed and underlying causes are discussed.     

In planta cleavage of carotenoids by <Emphasis Type="Italic">Arabidopsis</Emphasis> carotenoid cleavage dioxygenase 4 in transgenic rice plants

A family of carotenoid cleavage dioxygenases (CCDs) produces diverse apocarotenoid compounds via the oxidative cleavage of carotenoids as substrates. Their types are highly dependent on the action of the CCD family to cleave the double bonds at the specific position on the carotenoids. Here, we report in vivo function of the AtCCD4 gene, one of the nine members of the Arabidopsis CCD gene family, in transgenic rice plants. Using two independent single-copy rice lines overexpressing the AtCCD4 transgene, the targeted analysis for carotenoids and apocarotenoids showed the markedly lowered levels of β-carotene (74 %) and lutein (72 %) along with the changed levels of two β-carotene (C₄₀) cleavage products, a two-fold increase of β-ionone (C₁₃) and de novo generation of β-cyclocitral (C₁₀) at lower levels, compared with non-transgenic rice plants. It suggests that β-carotene could be the principal substrate being cleaved at 9–10 (9′–10′) for β-ionone and 7–8 (7′–8′) positions for β-cyclocitral by AtCCD4. This study is in planta report on the generation of apocarotenal volatiles from carotenoid substrates via cleavage by AtCCD4. We further verified that the production of these volatiles was due to the action of exogenous AtCCD4 and not the expression of endogenous rice CCD genes (OsCCD1, 4a, and 4b).     

Identification of a novel carotenoid, 2′-isopentenylsaproxanthin,by Jejuia pallidilutea strain 11shimoA1 and its increased production under alkaline condition

Carotenoids are a class of naturally occurring pigment, carrying out important biological functions in photosynthesis and involved in environmental responses including nutrition in organisms. Saproxanthin and myxol, which have monocyclic carotenoids with a γ-carotene skeleton, have been reported to show a stronger antioxidant activity than those with β-carotene and zeaxanthin. In this research, a yellow-orange bacterium of strain 11shimoA1 (JCM19538) was isolated from a seaweed collected at Nabeta Bay (Shizuoka, Japan). The 16S rRNA gene sequence of strain 11shimoA1 revealed more than 99.99 % similarity with those of Jejuia pallidilutea strains in the family Flavobacteriaceae. Strain 11shimoA1 synthesized two types of carotenoids. One of them was (3R, 3’R)-zeaxanthin with dicyclic structure and another was identified as (3R, 2’S)-2′-isopentenylsaproxanthin, a novel monocyclic carotenoid with pentenyl residue at C-2′ position of saproxanthin, using FAB-MS, ¹H NMR, and CD analyses. Culturing strain 11shimoA1 in an alkaline medium at pH 9.2 resulted in a markedly increased in production of 2′-isopentenylsaproxanthin per dry cell weight, but a decreased in zeaxanthin production as compared to their respective production levels in medium with pH 7.0. These carotenoids are likely to play some roles in the adaptation of the bacterium to the environmental conditions.     

The Composition of Carotenoids in Tissues of the Ascidian <Emphasis Type="Italic">Botryllus schlosseri</Emphasis> (Pallas, 1766) from the Black Sea

The composition of carotenoids was investigated in tissues of the colonial sea squirt Botryllus schlosseri (Pallas, 1766), which inhabits the Crimean coast near the city of Sevastopol. The total carotenoid amount of B. schlosseri was found to be 8.7 ± 4.6 mg/100 g of wet weight. Eleven carotenoids, that is, ß-carotene, 7,8-didehydroastaxanthin, 7,8,7',8',-tetradehydroastaxanthin, pectenolone, 4-ketoalloxanthin, diatoxanthin, diadinoxanthin, fucoxanthin, astaxanthin, alloxanthin, and halocynthiaxanthin, were identified in B. schlosseri with the use of the chromatographic and mass-spectrophotometric methods (UV/Vis, ESITOF/MS, and partially ¹H-NMR). Among these, halocynthiaxanthin (20.8% of the total content of carotenoids), alloxanthin (15.2%), and astaxanthin (12.1%) were found to be the major carotenoids. A comparative analysis of the composition of carotenoids in tissues of B. schlosseri was carried out for different regions of the World Ocean.     

Carotenoids of clam,coral and nudibranch zooxanthellae in aposymbiotic culture

The carotenoids of unialgal cultures originating from symbiotic zooxanthellae of two molluscan (Tridacna crocea, a giant clam, and Pteraeolidia ianthine a nudibranch) and one cnidian (Pseudopterogorgia bipinnata, a gorgonian coral) host have been analysed by HPLC or TLC procedures combined with several spectroscopic techniques including MS and NMR. A high total carotenoid content (0.45-0.63% of the dry wt) was obtained. The carotenoid pattern with C₃₇-norcarotenoids (peridinin and pyrrhoxanthin) comprising around 80% of total carotenoids, and β,β-carotene (2%), the ailenic dinoxanthin (3–4%) and the acetylenic diatoxanthin (1–3%) and diadinoxanthin (7–9%) representing minor C₄₀-carotenoids, corresponds to that of peridinin-producing free-living dinoflagellates. Supplementary ¹H NMR and ¹³C NMR data are reported for peridinin and pyrrhoxanthin. A polar, minor carotenoid, P447, was partly characterized as containing a disaccharide glycosidically bound to an allenic carotenoid aglycone. Re-evaluation of previous reports suggests the wide-spread occurrence of related carotenoid disaccharides in Dinophyceae for which they are considered a new chemosystematic marker.     

On the state of carotenoids bound to reaction centers of photosynthetic bacteria: A resonance raman study

The carotenoids bound to reaction centers of wild, Ga and GlC strains of Rhodopseudomonas spheroides, of Rhodospirillum rubrum, strain S1 and of Rhodopseudomonas viridis, yield very similar, but unusual resonance Raman spectra. Through a comparison with resonance Raman spectra of 15,15′-cis-β-carotene, these carotenoids are shown to assume cis conformations, while the corresponding chromatophores contain all-trans forms only. These cis conformations likely are identical for all the carotenoids studied. They remain unaffected by variations of temperature from 20 to 300 K as well as by the redox state of $\text{P-870}$. They are unstable, being rapidly isomerised towards the all-trans forms when extracted from the reaction centers. The possible nature of these conformers is discussed on the basis of their electronic and vibrational spectra.     

Carotenoids of Eriobotrya japonica

The carotenoids of the loquat fruit Eriobotrya japonica Golden Nugget variety, were investigated. They were identified according to their chromatographic, spectrophotometric and chemical properties and compared with standard pigments. For some of the carotenoids, MS were determined. Pulp and peels were investigated separately. The main pattern of the pulp carotenoids was β-carotene (33%), γ-carotene (6%), cryptoxanthin (22%), lutein, violaxanthin and neoxanthin, each about 3–4%. The peel, with a carotenoid content 5 times as high, had a similar pattern, but the ratio between the main pigments differed: β-carotene (50%); γ-carotene (5%); cryptoxanthin (5%); lutein (13%); violaxanthin, neoxanthin, 3–4%. The carotenoids of the loquat (subfamily Maloideae) were very similar to those of the apricot (Prunus armeniaca-subfamily Prunoideae) both of the family of Rosaceae. The intergeneric differences are more pronounced, which is of possible taxonomic significance. The lower concentration of cryptoxanthin and the high concentration of lutein in the peels is noteworthy and of biosynthetic interest.     

Delineation of the intimate details of the backbone conformation of pyridine nucleotide coenzymes in aqueous solution.

The noise free 300 MHz ¹H NMR spectra of β-DPN⁺, recorded in the Fourier mode at 12° and 68°C have been completely analysed by extensive computer simulation. It is shown, whether the coenzyme exists as an equilibrium mixture of folded ? extended forms (12°C) or in overwhelminghly extended forms (68°C), the backbone of both the nicotinamide and adenine fragments preferentially exist in ${}^2\text{E-gg-g′g′}$ conformation. This orientation is significantly different from those reported in the solid state for the extended species in contact with the enzyme where ${}^2\text{E-tg-g′g′}$ and ${}^3\text{E-tg-g′g′}$ orientations have been observed. It is suggested that specific interactions of the backbone with the various amino acid residues in the enzyme induces conformational aberrations in the backbone. Intimate details of the backbone conformation of the extended forms of AcPy-DPN⁺ and β-TPN⁺ are also presented.     

Synthesis of RNA polymerase in Escherichia coli B-r growing at different rates

Polyacrylamide gel electrophoresis of unfractionated sodium dodecyl sulfate lysates of Escherichia coli$\text{B}\text{r}$ has been used to investigate the synthesis of β and β′ subunits of RNA polymerase as a function of bacterial growth rate. In succinate (μ = 0.67 doublings/h), glucose (μ = 1.36 doublings/h) and glucose/amino acids (μ = 2.10 doublings/h) supplemented media, the fraction of [¹⁴C]leucine-labeled β and β′ protein/total protein was found to be 1.05, 1.31 and 1.56%, respectively. Comparison of these values with recent estimates from this laboratory of the differential rate of synthesis of functioning RNA polymerase suggests an excess of total over functioning RNA polymerase. The significance of these data in reference to the regulation of RNA polymerase synthesis is discussed.     

Prasinoxanthin—a chemosystematic marker for algae

A new coccoid marine alga (clone Ω 48-23) contained chlorophylls a and b and carotenoids consisting of β,β-carotene (3% of total), β,ε-carotene (1%), zeaxanthin (2%), neoxanthin (21%), two minor unknowns (2 + 2%) and prasinoxanthin (69%). Prasinoxanthin is identical with xanthophyll K, previously considered characteristic of prasinophytes. From spectroscopic and chemical evidence prasinoxanthin is assigned the structure (3′R,-6′R)-3,6,3′ trihydroxy-7,8-dihydro-γ,ε-caroten-8-one, with tentative 3R,6R chirality from biogenetic considerations, thus representing the first algal carotenoid with a γ-end group. The structural relationship between prasinoxanthin and siphonaxanthin (ex Prasinophyceae and Siphonales) is discussed in chemosystematic terms.     

Comparative biochemical studies of carotenoids in sea-urchins—II. The more primitive sea-urchins belonging to the orders Cidaroida,Echinothurioida, Diadematoida and Arbacioida

• 1.1. The carotenoids of seven species of more primitive sea-urchins, [orders Cidaroida (I), Echinothurioida (II), Diadematoida (III), and Arbacioida (IV)] were investigated from the comparative biochemical point of view.
• 2.2. β,β-carotene and β-echinenone have been isolated as major carotenoids in (I) and (III, IV), respectively. In (II), β,β-carotene, β-echinenone, canthaxanthin and (3S,3′S)-astaxanthin were foundto be predominant carotenoids.
• 3.3. The carotenoid patterns of (I) which is the most primitive sea-urchin from the phylogenetic point of view, and of (II) which is direct developers with non-feeding larvae, were quite different from those of the other sea-urchins showing typical development with feeding larvae.

     

Lipid-dissolved γ-carotene, β-carotene,and lycopene in globular chromoplasts of peach palm (Bactris gasipaes Kunth) fruits

Main conclusion

High levels of β-carotene, lycopene, and the rare γ-carotene occur predominantly lipid-dissolved in the chromoplasts of peach palm fruits. First proof of their absorption from these fruits is reported. The structural diversity, the physical deposition state in planta, and the human bioavailability of carotenoids from the edible fruits of diverse orange and yellow-colored peach palm (Bactris gasipaes Kunth) varieties were investigated. HPLC–PDA–MSⁿ revealed a broad range of carotenes, reaching total carotenoid levels from 0.7 to 13.9 mg/100 g FW. Besides the predominant (all-E)-β-carotene (0.4–5.4 mg/100 g FW), two (Z)-isomers of γ-carotene (0.1–3.9 mg/100 g FW), and one (Z)-lycopene isomer (0.04–0.83 mg/100 g FW) prevailed. Approximately 89–94 % of total carotenoid content pertained to provitamin A carotenoids with retinol activity equivalents ranging from 37 to 609 µg/100 g FW. The physical deposition state of these carotenoids in planta was investigated using light, transmission electron, and scanning electron microscopy. The plastids found in both orange and yellow-colored fruit mesocarps were amylo-chromoplasts of the globular type, containing carotenoids predominantly in a lipid-dissolved form. The hypothesis of lipid-dissolved carotenoids was supported by simple solubility estimations based on carotenoid and lipid contents of the fruit mesocarp. In our study, we report first results on the human bioavailability of γ-carotene, β-carotene, and lycopene from peach palm fruit, particularly proving the post-prandial absorption of the rarely occurring γ-carotene. Since the physical state of carotenoid deposition has been shown to be decisive for carotenoid bioavailability, lipid-dissolved carotenoids in peach palm fruits are expected to be highly bioavailable, however, further studies are required.     

Conformations and CD curves of cyclo(L- or D-Phe-L-Pro-Aca): cyclized models for specific types of β-bends

Cyclic tripeptides cyclo(L-Phe-L-Pro-Aca) (molecule $\text{3}$) (Aca, ?-aminocaproic acid) and cyclo(-D-Phe-L-Pro-Aca) (molecule $\text{4}$) are designed as models of specific types of β-bend. Energy calculation and ¹H and ¹³C NMR studies have indicated that peptides $\text{3}$ and $\text{4}$ form β-bend types VI and II', respectively. Circular dichroism spectra of $\text{4}$ have a double minimum negative band at the region of 200–230 nm like those of gramicidin S. The spectra of $\text{3}$, forming the cis peptide bond just before Pro, have a negative extremum at the 210–213 nm region. The spectra are used to estimate the contribution of various bend types in peptides.β-BendCD MeasurementConformational energy calculationCyclic peptideGramicidin SNMR measurement     

Assessment of carotenoid production by Dunaliella salina in different culture systems and operation regimes

The effect of operation regime and culture system on carotenoid productivity by the halotolerant alga Dunaliella salina has been analyzed. Operation strategies tested included batch and semi continuous regime, as well as a two-stage approach run simultaneously in both, open tanks and closed reactor. The best results were obtained with the closed tubular photobioreactor. The highest carotenoid production (328.8 mg carotenoid l⁻¹ culture per month) was achieved with this culture system operated following the two-stage strategy. Also, closed tubular photobioreactor provided the highest carotenoid contents (10% of dry weight) in Dunaliella biomass and β-carotene abundance (90% of total carotenoids) as well as the highest 9-cis to all-trans β-carotene isomer ratio (1.5 at sunrise).