Molecular diversity, metabolic transformation, and evolution of carotenoid feather pigments in cotingas (Aves: Cotingidae)

Abstract Carotenoid pigments were extracted from 29 feather patches from 25 species of cotingas (Cotingidae) representing all lineages of the family with carotenoid plumage coloration. Using high-performance liquid chromatography (HPLC), mass spectrometry, chemical analysis, and 1 H-NMR, 16 different carotenoid molecules were documented in the plumages of the cotinga family. These included common dietary xanthophylls (lutein and zeaxanthin), canary xanthophylls A and B, four well known and broadly distributed avian ketocarotenoids (canthaxanthin, astaxanthin, a-doradexanthin, and adonixanthin), rhodoxanthin, and seven 4-methoxy-ketocarotenoids. Methoxy-ketocarotenoids were found in 12 species within seven cotinga genera, including a new, previously undescribed molecule isolated from the Andean Cock-of-the-Rock Rupicola peruviana, 3 0 -hydroxy-3-methoxy-b,b-carotene-4-one, which we name rupicolin. The diversity of cotinga plumage carotenoid pigments is hypothesized to be derived via four metabolic pathways from lutein, zeaxanthin, b-cryptoxanthin, and b-carotene. All metabolic transformations within the four pathways can be described by six or seven different enzymatic reactions. Three of these reactions are shared among three precursor pathways and are responsible for eight different metabolically derived carotenoid molecules. The function of cotinga plumage carotenoid diversity was analyzed with reflectance spectrophotometry of plumage patches and a tetrahedral model of avian color visual perception. The evolutionary history of the origin of this diversity is analyzed phylogenetically. The color space analyses document that the evolutionarily derived metabolic modifications of dietary xanthophylls have resulted in the creation of distinctive orange-red and purple visual colors

Carotenoids from the crimson and maroon plumages of Old World orioles (Oriolidae)

a b s t r a c t Recent analyses of the orange, red, and purple plumages of cotingas (Cotingidae) and broadbills (Eurylaimidae) revealed the presence of novel carotenoid molecules, suggesting that the diversity of pigments and the metabolic transformations they undergo are not yet fully understood. Two Old World orioles, the Black-and-Crimson Oriole Oriolus cruentus, and the Maroon Oriole Oriolus traillii, exhibit plumage colors that are similar to those of some cotingas and broadbills. To determine if these oriole plumage colors are produced by the same carotenoids or with other molecules, we used high-performance liquid chromatography (HPLC), mass spectrometry, and chemical analyses. The data show that the bright red feathers of O. cruentus contain a suite of keto-carotenoids commonly found in avian plumages, including canthaxanthin, adonirubin, astaxanthin, papilioerythrinone, and a-doradexanthin. The maroon feathers of O. traillii were found to contain canthaxanthin, a-doradexanthin, and one novel carotenoid, 3 0 ,4-dihydroxy-e,ecarotene-3-one, which we have termed ''4-hydroxy-canary xanthophyll A.'' In this paper we propose the metabolic pathways by which these pigments are formed. This work advances our understanding of the evolution of carotenoid metabolism in birds and the mechanisms by which birds achieve their vivid plumage colorations

Spectral heterogeneity and carotenoid-to-bacteriochlorophyll energy transfer in LH2 light-harvesting complexes from Allochromatium vinosum

Photosynthetic organisms produce a vast array of spectral forms of antenna pigment-protein complexes to harvest solar energy and also to adapt to growth under the variable environmental conditions of light intensity, temperature, and nutrient availability. This behavior is exemplified by Allochromatium (Alc.) vinosum, a photosynthetic purple sulfur bacterium that produces different types of LH2 light-harvesting complexes in response to variations in growth conditions. In the present work, three different spectral forms of LH2 from Alc. vinosum, B800-820, B800-840, and B800-850, were isolated, purified, and examined using steady-state absorption and fluorescence spectroscopy, and ultrafast time-resolved absorption spectroscopy. The pigment composition of the LH2 complexes was analyzed by high-performance liquid chromatography, and all were found to contain five carotenoids: lycopene, anhydrorhodovibrin, spirilloxanthin, rhodopin, and rhodovibrin. Spectral reconstructions of the absorption and fluorescence excitation spectra based on the pigment composition revealed significantly more spectral heterogeneity in these systems compared to LH2 complexes isolated from other species of purple bacteria. The data also revealed the individual carotenoid-to-bacteriochlorophyll energy transfer efficiencies which were correlated with the kinetic data from the ultrafast transient absorption spectroscopic experiments. This series of LH2 complexes allows a systematic exploration of the factors that determine the spectral properties of the bound pigments and control the rate and efficiency of carotenoid-to-bacteriochlorophyll energy transfer

Graded Maximal Exercise Testing to Assess Mouse Cardio-Metabolic Phenotypes

<div><p>Functional assessments of cardiovascular fitness (CVF) are needed to establish animal models of dysfunction, test the effects of novel therapeutics, and establish the cardio-metabolic phenotype of mice. In humans, the graded maximal exercise test (GXT) is a standardized diagnostic for assessing CVF and mortality risk. These tests, which consist of concurrent staged increases in running speed and inclination, provide diagnostic cardio-metabolic parameters, such as, VO_2max, anaerobic threshold, and metabolic crossover. Unlike the human-GXT, published mouse treadmill tests have set, not staged, increases in inclination as speed progress until exhaustion (PXT). Additionally, they often lack multiple cardio-metabolic parameters. Here, we developed a mouse-GXT with the intent of improving mouse-exercise testing sensitivity and developing translatable parameters to assess CVF in healthy and dysfunctional mice. The mouse-GXT, like the human-GXT, incorporated staged increases in inclination, speed, and intensity; and, was designed by considering imitations of the PXT and differences between human and mouse physiology. The mouse-GXT and PXTs were both tested in healthy mice (C57BL/6J, FVBN/J) to determine their ability to identify cardio-metabolic parameters (anaerobic threshold, VO_2max, metabolic crossover) observed in human-GXTs. Next, theses assays were tested on established diet-induced (obese-C57BL/6J) and genetic (cardiac isoform <i>Casq2</i>^-/-) models of cardiovascular dysfunction. Results showed that both tests reported VO_2max and provided reproducible data about performance. Only the mouse-GXT reproducibly identified anaerobic threshold, metabolic crossover, and detected impaired CVF in dysfunctional models. Our findings demonstrated that the mouse-GXT is a sensitive, non-invasive, and cost-effective method for assessing CVF in mice. This new test can be used as a functional assessment to determine the cardio-metabolic phenotype of various animal models or the effects of novel therapeutics.</p></div

Anaerobic threshold and maximum speed assess dysfunction in mice with the GXT_m, but not the PXT_m.

<p>(A) Average RER kinetics from same from WT (dashed line), <i>Casq2</i>^-/- (solid thick line), and obese (solid line) mice performed the PXT_m and GXT_m. (B) AT was reported as %AT, a time point where AT occurred/total test time in mouse groups (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0148010#pone.0148010.g003" target="_blank">Fig 3</a>). (C) Maximum speed achieved on test (m/m). For all measures, asterisks indicates significance at the alpha = .007 level (MANOVA, multiple comparisons Tukey HSD for the PXT_m and GXT_m of WT v. obese and WT v. <i>Casq2</i>^-/-), hash indicates significant difference at the alpha = .05 level between tests for the same genotype (Student’s t-Test), and diamond indicates significance at the alpha = .007 level (mean ± SD, MANOVA, multiple comparisons Tukey HSD for the PXT_m and GXT_m of obese v. <i>Casq2</i>^-/-).</p

Carbohydrate and fat oxidation kinetics can be used to identify the crossover point in the GXT_m, but not the PXT_m.

<p>Averaged fuel utilization kinetics in WT (<i>n</i> = 7), obese (<i>n</i> = 11), and <i>Casq2</i>^-/- (<i>n</i> = 4) mice. Fat (dashed line) and carbohydrate (Carb, solid line)) oxidation were derived from RER as described in S3 Table during the PXT_m (A) and GXT_m tests (B). In GXT_m tests, the arrow indicates crossover, the point at which carbohydrate and fat oxidation intersect (dashed arrows).</p