Steroid compounds of marine sponges. III. 24-Ethyl-25-methylcholesta-5,22-dien-3β-OL — A new marine sterol from the spongeHalichondria sp.

A new sterol — 24 ethyl-25-methylcholesta-5,22-dien-3β-ol — has been isolated by column chromatography on silica gel from extracts of the spongeHalichondria sp. Its structure has been established on the basis of an analysis of GLC-MS results and of PMR and¹³C NMR spectroscopy and has been confirmed by ozonolysis.     

Raman spectroscopy of hot desert, high altitude epilithic lichens

Twenty-three highly-coloured lichen specimens belonging to the genera Candelariella, Aspicilia and Xanthoria from high altitude sites in the Atacama Desert, Chile, 2300-4500 metres, have been analysed non-destructively by Raman spectroscopy. The vibrational band assignments in the spectra of the specimens, which were still attached to their limestone or sandstone substrata, were accomplished by comparison with the chemical compositions obtained from wet chemical extraction methods. Carotenoids and chlorophyll were found in all specimens as major components and the characteristic spectral signatures of calcium oxalate monohydrate (whewellite) and dihydrate (weddellite) could be identified; chemical signatures were found for these materials even in lichen thalli growing on the non-calcareous substrata, indicating probably that the calcium was provided here from wind- or rain-borne sources. The Raman spectral biomarkers for a variety of protective biomolecules and accessory pigments such as usnic acid, calycin, pulvinic acid dilactone and rhizocarpic acid have been identified in the lichens, in broad agreement with the chemical extraction profiles. The present study indicates that some form of non-destructive taxonomic identification based on Raman spectroscopy was also possible.     

A novel extremophile strategy studied by Raman spectroscopy

A case is made for the classification of the colonisation by Dirina massiliensis forma sorediata of pigments on ancient wall-paintings as extremophilic behaviour. The lichen encrustations studied using FT-Raman spectroscopy have yielded important molecular information which has assisted in the identification of the survival strategy of the organism in the presence of significant levels of heavy metal toxins. The production of a carotenoid, probably astaxanthin, at the surface of the lichen thalli is identified from its characteristic biomolecular signatures in the Raman spectrum, whereas the presence of calcium oxalate dihydrate (weddellite) has been identified at both the upper and lower surfaces of the thalli and in core samples taken from depths of up to 10mm through the encrustation into the rock substrate. The latter observation explains the significant disintegrative biodeteriorative effect of the colonisation upon the integrity of the wall-paintings and can be used to direct conservatorial and preservation efforts of the art work. A surprising result proved to be the absence of Raman spectroscopic evidence for the complexation of the metal pigments by the oxalic acid produced by the metabolic action of the organisms, unlike several cases that have been reported in the literature.     

Structural Characterization of a Novel Antioxidant Pigment Produced by a Photochromogenic <Emphasis Type="Italic">Microbacterium oxydans</Emphasis> Strain

The Microbacteriaceae family, such as Microbacterium, is well known for its ability to produce carotenoid-type pigments, but little has been published on the structure of such pigments. Here, we isolated the yellow pigment that is responsible for the yellowish color of a Microbacterium oxydans strain isolated from a decomposing stump of a resinous tree. The pigment, which is synthesized when the bacterium is grown under light, was purified and characterized using several spectroscopic analyses, such as ultraviolet-visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), ¹H and ¹³C nuclear magnetic resonance (¹H NMR, ¹³C NMR), and high-resolution mass spectrometry (HRMS). From these analysis, a molecular formula (C₂₇H₄₂O₂) and a chemical structure (8-hydroxymethyl-2,4,12-trimethyl-14-(2,6,6-trimethyl-cyclohex-2-enyl)-teradeca-3,7,9,11,13-pentan-2-ol) were deduced. The chemical properties of the pigment, such as aqueous stability at different pH, stability in different organic solvents, and antioxidant capacity, are also reported. Together, these data and previous studies have resulted in the identification of a new antioxidant pigment produced by M. oxydans. To the best of our knowledge, this is the first thorough investigation of this carotenoid-like pigment in the Microbacterium genera.     

Diagnosis of inflammatory lesions by high-wavenumber FT-Raman spectroscopy

The Raman spectroscopy technique has been extensively used for biological sample characterization. In particular, the fingerprint spectral region (800?C1,800?cm^?1) has been shown to be very promising for optical biopsy purposes. However, limitations for the widespread use of Raman-based optical biopsy technique still persist. For example, fluorescence when one uses visible light (400?C700?nm) spectral sources is often present and appears to affect the mid-IR/Raman region more than the high-wavenumber region (2,800?C3,600?cm^?1). But, both the higher wavenumber spectral region and the mid-IR/Raman region can be fluorescence-free when one uses lasers sources, which do not cause fluorescence, for example, 1,064, 830 or 785?nm sources. In addition, the Raman spectral signal of inflammatory infiltrates can influence the biopsy diagnoses and is one important source of misdiagnosis of normal versus pathological tissues. The present work seeks to evaluate whether the Raman spectra in the high-wavenumber spectral region can be used to distinguish between oral inflammatory fibrous hyperplasia (IFH) lesions and normal (NM) tissues and hence be used as a new diagnostic tool. Thirty spectra of oral IFH lesions and NM tissues from biopsies of 12 patients were analyzed using both principal components analysis (PCA) and a binary logistic regression (BLR) model. It was found that the high-wavenumber region Raman spectra can be used to discriminate between NM tissue and oral IFH tissues by analyzing the 2,800?C3,050?cm^?1 (CH₂ and CH₃ vibrations of lipids and proteins) and 3,050?C3,600?cm^?1 (CH, OH, and NH vibrations of proteins and water) spectral intensities. A simple classification model based on the relative areas of the above cited regions resulted in concordant pairs of 95.3%. Considering the standard errors in the model parameters, it was found that the sensitivity (Se) and specificity (Sp) fall in the interval 87%?<?Se?<?100% and 73%?<?Sp?<?93%, respectively. In addition, it has been found that the Raman scattering cross-sections in the NH, OH, and CH stretching region are more intense than in the mid-IR/Raman (fingerprint) region.     

Bioprospecting of Microalgae Isolated from the Adriatic Sea: Characterization of Biomass,Pigment, Lipid and Fatty Acid Composition,and Antioxidant and Antimicrobial Activity

Marine microalgae and cyanobacteria are sources of diverse bioactive compounds with potential biotechnological applications in food, feed, nutraceutical, pharmaceutical, cosmetic and biofuel industries. In this study, five microalgae, Nitzschia sp. S5, Nanofrustulum shiloi D1, Picochlorum sp. D3, Tetraselmis sp. Z3 and Tetraselmis sp. C6, and the cyanobacterium Euhalothece sp. C1 were isolated from the Adriatic Sea and characterized regarding their growth kinetics, biomass composition and specific products content (fatty acids, pigments, antioxidants, neutral and polar lipids). The strain Picochlorum sp. D3, showing the highest specific growth rate (0.009 h⁻¹), had biomass productivity of 33.98 ± 0.02 mg L⁻¹ day⁻¹. Proteins were the most abundant macromolecule in the biomass (32.83–57.94%, g g⁻¹). Nanofrustulum shiloi D1 contained significant amounts of neutral lipids (68.36%), while the biomass of Picochlorum sp. D3, Tetraselmis sp. Z3, Tetraselmis sp. C6 and Euhalothece sp. C1 was rich in glycolipids and phospholipids (75%). The lipids of all studied microalgae predominantly contained unsaturated fatty acids. Carotenoids were the most abundant pigments with the highest content of lutein and neoxanthin in representatives of Chlorophyta and fucoxanthin in strains belonging to the Bacillariophyta. All microalgal extracts showed antioxidant activity and antimicrobial activity against Gram-negative E. coli and S. typhimurium and Gram-positive S. aureus.     

Assignment and anharmonicity analysis of overtone and combination bands observed in the resonance Raman spectra of carotenoids

The resonance Raman spectra of all-trans carotenoids have been observed in the region of 5000-500 cm⁻¹ for samples in glassy solution at 77 K and in the in vivo state at room temperature. Prominent bands in the wavenumber region higher than 2000 cm⁻¹ are assigned to either overtones or combinations of three modes due to skeletal stretches and the CH₃ in-plane rock. From the wavenumbers of the observed Raman bands, anharmonicity constants for these three modes (including cross-term constants) are obtained. It is found that, for each carotenoid studied, the cross-term anharmonicity constant between the CC and CC stretches is significantly larger than the other anharmonicity constants.     

Cytotoxic pigments from new zealand sponges of the genus latrunculia : discorhabdins a,b and c

Discorhabdins A, B and C have been isolated as the major cytotoxic pigments of three different Latrunculia sponge species from New Zealand. The ¹H- and ¹³C-NMR spectra of the previously reported discorhabdin C 1 have been assigned. The structures of discorhabdins A 2 and B 3 have been established by spectral comparisons (especially NMR)'with 1. The discorhabdins are strongly cytotoxic (P388 ED₅₀'s 0.03-0.1 μg/ml) and antimicrobial.     

Heated goethite and natural hematite: Can Raman spectroscopy be used to differentiate them?

Minerals have been used as pigments for thousands of years. Red and yellow pigments are generally associated with iron oxides or, specifically, hematite (α-Fe₂O₃) and goethite (α-FeOOH). It is well known that, under heating, goethite dehydrates forming hematite. An interesting question yet to be answered is whether the pre-historical artists used this knowledge to obtain other shades of red and yellow or used the raw mineral directly.Raman spectroscopy was employed to address this question and XRD, TEM and TG were used as supporting techniques. Ex situ and in situ Raman spectra were obtained and it was observed that in the 250–300 °C temperature range, broad hematite features appears as a consequence of goethite dehydration. In the spectra of the heated sample a band at 657 cm⁻¹ is of particular interest, as it is much more intense than in natural hematite; the possibility that it could be assigned as a magnetite band was discarded. At higher temperatures (900–1000 °C) the disordered structure is perfected and a Raman spectrum similar to a crystalline natural hematite sample is obtained.Temperatures in the 600–700 °C range can be easily reached, thus disordered hematite could be obtained from goethite heating even in ancient times, however, heat is not the only agent able to produce disordered hematite, since grinding, biodegradation and weathering can produce the same effect. Raman spectra obtained from weathered samples are also representative of disordered hematite.The data here reported indicate that it is not possible to differentiate heated goethite from other disordered hematites.     

Archaeological pottery from Nasca culture studied by Raman and Mössbauer spectroscopy combined with X-ray diffraction

In the present paper, we report on a study of archaeological fragments from Nasca ceramics using Raman and Mössbauer spectroscopy combined with X-ray diffraction (XRD). By combining results obtained by these methods it is possible to quantitatively determine the paints composition, temperature and environment during the firing. The samples were collected from the Ceremonial Centre of Cahuachi in Southern coast of Peru. Raman spectroscopy allows us to determine the composition of the different pigments used in the preparation of Nasca ceramic. The results show that the composition of the white pigments is formed by rutile and anatase while the black and red pigments are formed by amorphous carbon and hematite, respectively. The Mössbauer spectra were measured at room temperature (RT) and show the presence of components associated with Fe³⁺ indicating an oxidizing environment during the manufacturing process of the ceramic. The analysis is complemented by data obtained by X-ray diffraction suggesting firing temperatures around 950 °C, in agreement with Raman measurements.     

NMR identification of ethyl-linked anthocyanin-flavanol pigments formed in model wine ferments

The ethyl-linked pigments produced by the reaction between either catechin or epicatechin and malvidin 3-O-glucoside with added acetaldehyde have been isolated and characterised by NMR spectroscopy. These pigments are generated in high concentrations in model fermentations containing added malvidin 3-O-glucoside and (epi)catechin when inoculated with Saccharomyces cerevisiae yeast. This confirms that these pigments are produced during fermentation from metabolically produced acetaldehyde and provides evidence that the formation of these pigments may be a significant contributor to the purple colouration of young red wines.     

Spectres de vibration de pigments rouges de la famille des quinacridones

The i.r. and Raman spectra of various crystalline phases of the trans linear quinacridone and some methylated and chlorinated derivatives have been investigated between 4000 and 200 cm⁻¹. Each of these pigments has been characterized spectroscopically and an assignment for intramolecular fundamentals is given in terms of group frequencies. The strength and length of NH ⋯ O hydrogen bonds have been assessed from the vNH frequency and correlated with the pigment colour which is principally determined by intermolecular interactions rather than by the substituent hypso(batho)chromic effect. The NH ⋯ O distance increases from 2.87 Å for the red compounds to 2.93 Å for the purple ones.     

Rapid and quantitative extraction method for the determination of chlorophylls and carotenoids in olive oil by high-performance liquid chromatography

Colour is an organoleptic characteristic of virgin olive oil and an important attribute that affects the consumer perception of quality. Chlorophylls and carotenoids are the main pigments responsible for the colour of virgin olive oil. A simple analytical method for the quantitative determination of chlorophylls and carotenoids in virgin olive oils has been developed. The pigments were isolated from small samples of oil (1.0 g) by solid-phase extraction using diol-phase cartridges (diol-SPE), and the extract was analysed by reverse-phase HPLC with diode-array UV detection. Chromatographic peak resolution, reproducibility (coefficient of variation (C.V.) <4.5%) and recovery (>98.4%) for each component were satisfactory. A comparative study of the proposed method was performed versus classical liquid-liquid extraction (LLE) with N,N′-dimethylformamide and solid-phase extraction using a C18 column (C18-SPE). While 96.4% of the pigments were recovered by LLE, only 51.3% were isolated by C18-SPE in comparison to diol-SPE. Likewise, a higher alteration of pigment composition was observed when such LLE and C18-SPE procedures were used. In this sense, a higher ratio of pheophytin in comparison to that isolated by the diol-SPE procedure was achieved with both extraction procedures, indicating a greater extent of the pheophytinization reaction. Therefore, quantification of pigments from virgin olive oil by diol-SPE followed by RP-HPLC was found to be rapid, simple, required only a small amount of sample, consumed only small amounts of organic solvents, and provided high recoveries, accuracy and precision.     

Separation of Photosynthetic Pigments by High-performance Liquid Chromatography: Comparison of Column Performance,Mobile Phase,and Temperature

High-performance liquid chromatography (HPLC) has been commonly used as method of separating and identifying photosynthetic pigments such as chlorophylls and carotenoids because of such advantages as speed, high resolution and sensitivity. In this technique, high separation relies largely on the type of column material. This study compared the efficiency of five reverse-phase columns, C8, C18, C18 monolithic, π-NAP, and cholester, for separation of photosynthetic pigments at several fixed conditions of mobile phase and temperature. This investigation also analysed the parameters of Δt_R and t_R ratio for selected pigments and resolution for structural isomers, such as α- and β-carotene. Among above columns tested, cholester column is suitable for separation of pigments not only for a broad range of polarity, but also for hydrophobic pigments in a simple mobile phase. This finding can help in the selection of column and HPLC parameters in separating photosynthetic pigments.     

Transition metal allyls : III. The (η3-allyl)2M complexes of nickel,palladium and platinum: structural considerations

The structures of a series of (η³-allyl)₂M complexes of nickel, palladium and platinum have been investigated with the help of ¹³C NMR, ¹H NMR and Raman spectroscopy. The crystal structure of (η³-cyclooctatrienyl)₂Ni has been determined by X-ray methods; the two nickel-bonded η³-allyl groups are mutually trans.     

Simultaneous Raman and infrared spectroscopy: a novel combination for studying bacterial infections at the single cell level

Sepsis is a life-threatening clinical condition responsible for approximately 11 million deaths worldwide. Rapid and accurate identification of pathogenic bacteria and its antimicrobial susceptibility play a critical role in reducing the morbidity and mortality rates related to sepsis. Raman and infrared spectroscopies have great potential to be used as diagnostic tools for rapid and culture-free detection of bacterial infections. Despite numerous reports using both methods to analyse bacterial samples, there is to date no study collecting both Raman and infrared signatures from clinical samples simultaneously due to instrument incompatibilities. Here, we report for the first time the use of an emerging technology that provides infrared signatures via optical photothermal infrared (O-PTIR) spectroscopy and Raman spectra simultaneously. We use this approach to analyse 12 bacterial clinical isolates including six isolates of Gram-negative and six Gram-positive bacteria commonly associated with bloodstream infection in humans. To benchmark the single cell spectra obtained by O-PTIR spectroscopy, infrared signatures were also collected from bulk samples via both FTIR and O-PTIR spectroscopies. Our findings showed significant similarity and high reproducibility in the infrared signatures obtained by all three approaches, including similar discrimination patterns when subjected to clustering algorithms. Principal component analysis (PCA) showed that O-PTIR and Raman data acquired simultaneously from bulk bacterial isolates displayed different clustering patterns due to the ability of both methods to probe metabolites produced by bacteria. By contrast, signatures of microbial pigments were identified in Raman spectra, providing complementary and orthogonal information compared to infrared, which may be advantageous as it has been demonstrated that certain pigments play an important role in bacterial virulence. We found that infrared spectroscopy showed higher sensitivity than Raman for the analysis of individual cells. Despite the different patterns obtained by using Raman and infrared spectral data as input for clustering algorithms, our findings showed high data reproducibility in both approaches as the biological replicates from each bacterial strain clustered together. Overall, we show that Raman and infrared spectroscopy offer both advantages and disadvantages and, therefore, having both techniques combined in one single technology is a powerful tool with promising applications in clinical microbiology.

O-PTIR was used for simultaneous collection of infrared and Raman spectra from clinical pathogens associated with bloodstream infections.     

Fourier transform Raman spectroscopy of kandite clays

The Raman spectra of the kandite clay minerals, kaolinite, halloysite, dickite and nacrite, have been measured in the 180–3000 cm⁻¹ region using Fourier transform near-IR Raman spectroscopy. These clays have a very small Raman cross-section and long data collection times were often required to obtain good spectra. Each clay has its own unique characteristic Raman spectrum which enables each kandite to be identified easily. In contrast, it is quite difficult to distinguish kandite clays by IR spectroscopy. Nacrite and dickite have relatively intense Raman peaks in the 1000–1100 cm⁻¹ region, whereas kaolinite is characterized by an intense peak at 685 cm⁻¹ and halloysite at 470 cm⁻¹.     

Glebionis coronaria (L.) Cass. ex Spach (Asteraceae)- a new fabric dye with potential antibacterial properties

The paper elucidates first ever report on Glebionis coronaria (L.) Cass. ex Spach as a new dyeing agent with high antibacterial activity. Glebionis coronaria (L.) Cass. ex Spach which is also known as Garland/Crown Daisy belonging to the flowering plant family Asteraceae has been identified as a new precursor/candidate to produce highly efficient natural textile dye and a potential antibacterial agent. Natural dye from garland daisy was extracted from the dried petals using DCM and MeOH solvent system. Change in mordants yielded 12 different shades of colours. Spectroscopic analysis of these extracts revealed the presence of carotenoids and flavonoids pigments and hence giving varied shades of yellow, greenish yellow colours (Code No. is assigned to each colour). Alum and stannous chloride have been found to give bright colours while ferrous sulphate gave dark shades of colour. Antibacterial activity of the extracts was studied against non-pathogenic bacteria's, Staphylococcus aureus (Gram-positive bacteria) and for the first time for Aeromonas sp. (Gram-negative bacteria). Two different concentrations of 10 ​mg/ml DCM and methanol extracts using methanol as solvent were tested. Both DCM and methanol extracts have shown inhibition in Aeromonas sp. while only DCM extract was inhibiting S. aureus. The flower extracts has not been evaluated till date for its dyeing properties with different mordants along with their bactericidal activity. Therefore, our present work was to extract natural dye from the flowers of Glebionis Coronaria (L.) Cass. ex Spach. and to do a detailed study.     

New quinone from a marine sponge of the order dictyoceratida

Two pigments of quinoid nature, one of which has been identified as ilimaquinone, have been isolated from a hexane extract of a marine spongeHyatella sp., family Spongiidae, order Dictyoceratida. The second was a new benzoquinone of the drimane series with the composition C₂₂H₃₂O₅, which has been called hyatoquinone. Its structure has been established on the basis of spectral characteristics and chemical transformations.     

Acremines A-F, novel secondary metabolites produced by a strain of an endophytic Acremonium, isolated from sporangiophores of Plasmopara viticola in grapevine leaves

Six novel metabolites, acremines A-F have been isolated from agar cultures of a strain of Acremonium sp. Their structures and stereochemistry were elucidated using a combination of ¹³C and ¹H homo and heteronuclear 2D NMR experiments and X-ray analysis. Acremines A-D inhibited the germination of sporangia of Plasmopara viticola.