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Abstract

Like all animals, the red fox uses chemical signals for social communication. The supracaudal or tail gland smells of violets, attributed to the presence of carotenoid degradation products, or apocarotenoids, which commonly occur as aromatics in flowers. We have more fully characterized the scent chemistry of the fox tail gland. Volatile chemicals were analyzed by gas chromatography-mass spectrometry (GC-MS) and identified from their electron ionization mass spectra and Kovats retention indices. The 3 previously reported apocarotenoids were confirmed, and many additional compounds found. These include the apocarotenoids β-cyclocitral, β-homocitral, β-ionone, cyclic β-ionone, β-ionone-5,6-epoxide, α-ionene, α-ionone, 2,6,6-trimethylcyclohexanone (IUPAC 2,2,6-), 2,6,6-trimethyl-2-cyclohexen-1-one, 6-methyl-5-hepten-2-one (sulcatone), and geranyl acetone. Notably, sulcatone is a semiochemical in several species. 3,3-Dimethyl-2,7-octanedione was identified as a probable apocarotenoid which is likely to be a significant fox scent chemical. The γ-lactone of 4-hydroxyhexadecanoic acid (hexadecan-4-olide) was also found, one of a group of known mammalian signaling compounds. This rich mixture of volatile apocarotenoids implies an adequate consumption of plant carotenoids, which are known to be necessary for optimal health. Dietary carotenoids color the skin and feathers of some birds, used as a visual signal to conspecifics, and the floral aroma of the fox tail gland may provide an olfactory signal to other foxes.

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... , the observed behavioural changes in the foxes were likely caused by the stimulation of the VNS, evoked by pheromones in the faeces or urine, instead of specifically induced by the smells associated with these stimuli, which are primarily composed of volatile components, with an ephemeral presence in the external environment (González et al., 1991). McLean et al. (2019 characterised the chemical compounds excreted by fox tails, identifying several compounds (for example, sulcatone) that are used as semiochemicals in several mammal species, further illustrating the importance of the VNS for fox behaviours. ...
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We are entering one of the most exciting periods in the study of chemical communication since the first pheromones were identified some 40 years ago. This rapid progress is reflected in this book, the first to cover the whole animal kingdom at this level for 25 years. The importance of chemical communication is illustrated with examples from a diverse range of animals including humans, marine copepods, Drosophila, Caenorhabditis elegans, moths, snakes, goldfish, elephants and mice. It is designed to be advanced, but at the same time accessible to readers whatever their scientific background. For students of ecology, evolution and behaviour, this book gives an introduction to the rapid progress in our understanding of olfaction at the molecular and neurological level. In addition, it offers chemists, molecular and neurobiologists an insight into the ecological, evolutionary and behavioural context of olfactory communication.
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Bite force is often used as a predictive indicator of an animal's feeding ecology, although the premise that there is a direct link between diet and cranial morphology can be difficult to test empirically. Studies that have examined this question tend to rely on generalizations of a species' diet, and age and sex differences are rarely considered. Red foxes (Vulpes vulpes) are introduced predators in Australia, allowing large sample size collection through culling for comparison of skull morphology (size, morphometry, weight), demographics (age, sex) and diet (stomach contents). Over half (57%) of the 540 animals we sampled were juveniles (<1 year old; dispersing from their natal sites) and most variation in skull morphometry was driven by age; adults had significantly more robust skulls than juveniles, with greater estimated bite force. Sexual dimorphism (body mass and body length) was reflected in longer, heavier skulls of males. We also recorded significant sex and age differences in diet. Sheep carrion comprised 47-65% of diet volume; however, adult females ate less sheep but had more mice and invertebrates in their diet than males or juveniles of both sexes. This dietary separation for adult females does not appear to be directly due to estimated bite force constraints, but probably rather prey availability, which may reflect feeding behaviour and space use patterns. Juveniles (both sexes) showed as much consumption of sheep carrion as adult males, despite their lower estimated bite force than adults. This is the first study that directly compares ontogenetic and sex differences in the diet of a carnivore together with their cranial morphology and estimated bite force, and highlights limitations of inferring diet partitioning from skull morphology alone.
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Habitat loss and landscape degradation affect carnivorous mammal populations and the ecosystem services they provide, but these services are poorly assessed in semi-arid ecosystems. In the Ziziphus semiarid scrublands, a priority habitat for conservation in Europe, we investigated how red fox diet relates to habitat loss and landscape alteration. We further evaluated potential top-down effects of foxes on vegetation through seed dispersal and the control of rabbit herbivory (fruit depulpation interfering seed dispersal). By sampling fox scats, we evaluated the variation in fox diet and its relationship to landscape features and rabbit abundance and activity in 17 habitat remnants distributed throughout the Ziziphus habitat range. Fox diet varied, with diet diversity peaking at intermediate land-use diversity, likely as a consequence of fox's ability to use natural foods and human-derived resources. We confirmed that red fox acts as seed disperser for many species and that it might contribute to control rabbit population and its impact on Ziziphus lotus regeneration by interference on seed dispersal, though this needs experimental corroboration. However, these services were affected by landscape degradation. Our results show that red fox is fundamental for Ziziphus semiarid ecosystem providing key ecosystem services which are presently jeopardized by strong landscape degradation.
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Tea prepared by infusion of dried leaves of Camellia sinensis (L.) Kuntze, is the second world's most popular beverage, after water. Its consumption is associated with its chemical composition: it influences its sensory and nutritional quality addressing consumer preferences, and potential health benefits. This study aims to obtain an informative chemical signature of the volatile fraction of black tea samples from Ceylon by applying the principles of sensomics. In particular, several high concentration capacity (HCC) sample preparation techniques were tested in combination with GC × GC–MS to investigate chemical signatures of black tea volatiles. This platform, using headspace solid phase microextraction (HS-SPME) with multicomponent fiber as sampling technique, recovers 95% of the key-odorants in a fully automated work-flow. A group 123 components, including key-odorants, technological and botanical tracers, were mapped. The resulting 2D fingerprints were interpreted by pattern recognition tools (i.e. template matching fingerprinting and scripting) providing highly informative chemical signatures for quality assessment.
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The Danish pesticide residue monitoring programme evaluates compliance with the maximum residue levels established by the EU and monitors the residue levels in foods to enable an evaluation of the exposure of the Danish population to pesticides. The latter part of the programme included 25 different fruits, vegetables and cereals and processed foods. The commodities were chosen based on their contribution to the intake of pesticides in the Danish population. A total of 17,309 samples were collected during 2004–2011. The monitoring showed that the frequencies of pesticides were higher in samples of foreign origin than in samples of Danish origin both for samples with residues above or below the MRLs. Overall, pesticide residues were more frequently found in fruits and vegetables than the other groups of commodities; fruits had higher frequencies than vegetables. Residues above the MRLs were found in 2.6% of the samples. In plant commodities, 163 different substances were found in measurable concentrations. Residues of more than one pesticide (multiple residues) were found in 27% of all samples. A comparison of the frequencies of pesticide residues in commodities from different countries showed that Danish commodities with a lower frequency of pesticides.
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Cyclocitral (I) wird zu ?-Cyclogeraniol (II) reduziert, dessen Oxidation das Diol (III) mit dem 1,2-Diolsystem in cis-Stellung gibt.
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Chemical signals play an important role in intraspecific communication and social organization of many animals, but they also may be useful in interspecific recognition. In lizards, chemical signals are often contained in femoral gland secretions, of which composition may vary between species and populations. This may be especially important in recognition and reproductive isolation between closely related species. We analyzed by gas chromatography-mass spectrometry (GC-MS) the lipophilic fraction of femoral gland secretions of two closely related wall lizard species, Podarcis bocagei and Podarcis carbonelli to test for possible interspecific differences in chemical composition. We found 56 lipophilic compounds in femoral gland secretions of male P. bocagei and 60 in P. carbonelli. The main compounds were steroids and waxy esters, but we also found carboxylic acids and their esters, alcohols, amydes, aldehydes, squalene, ketones and furanones. There were significant differences between species with respect to the number and relative proportions of compounds. Differences in chemical composition might be a consequence of phylogenetic differences per se, but they could also be explained by ecological adaptation to different microclimatic conditions. These differences in chemical profiles may explain the known chemosensory interspecific recognition between these two lizards, contributing to their reproductive isolation.
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Focusing exclusively on the chemically mediated interactions between vertebrates, including humans and other animals and plants, this monograph combines information from widely scattered technical literature in different disciplines. It will be an indispensable reference for undergraduates, graduate students and researchers interested in how chemical signals are used for inter- and intra-specific communication in vertebrates. © Cambridge University Press 2006 and Cambridge University Press, 2009.
Article
Carotenoids have traditionally been subscribed to their role as accessory pigments in photosynthesis. However, the large and growing body of literature investigated on the field have revealed that carotenoids fulfill a plethora of essential roles in plants but also in animals and in humans. Recent studies emphasizing the functional role of molecules derived from carotenoids oxidation as β-cyclocitral or dihydroactinidiolide led to a renewed interest, opening a new era for the carotenoids research. This review brings together the knowledge obtained so far regarding diversity and functions of carotenoids, highlighting carotenoids versatility and the remarkable parallel roles of carotenoids in both plants and in animals. Evolutionary aspects and the responses of carotenoids to biotic and abiotic stresses are discussed. Furthermore, we outline the way in which one can understand the environmental regulation to enhance carotenoid content in food. In addition, an up-to-date overview of carotenoids as elements of information storage system for the responses to environmental signals is provided together with suggestions for future directions of research
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Significance A long-standing question in pheromone biosynthesis is the origin of the mevalonate pathway-derived precursor to frontalin, a key pheromone to the successful mass attack of conifer hosts by Dendroctonus bark beetles. Using a combination of genome and transcriptome analysis, functional characterization of expressed proteins, RNA interference, and transcript and metabolite analysis, we provide evidence that frontalin in the mountain pine beetle ( Dendroctonus ponderosae Hopkins) originates from the 20-carbon geranylgeranyl diphosphate rather than from 10-carbon geranyl diphosphate or 15-carbon farnesyl diphosphate. This result opens the way to study the later steps in frontalin biosynthesis.
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Understanding the role of urine marking in the territorial systems of wild mammals can be difficult, especially for nocturnal cryptic species. Even for common species, such as the red fox Vulpes vulpes, a comprehensive analysis of seasonal and sex differences has not been carried out. Using 6 years of infra-red video monitoring, we compared marking rates between months and between sexes. Urine marking was significantly lower during summer (June–August). Males urine marked significantly more frequently than females during late summer and autumn, but not winter. Males marked more frequently than females also during March. There was no increase during the breeding season for either sex. Our results correlate with previous partial data but demonstrate how urine marking rates vary across the year. They also further support the greater role of males in fox territorial maintenance. Urine marking is lowest during summer when territorial intrusions are least, whilst the higher male urine marking rate in March reflects the period when females are denning. Overall, our results provide the first comprehensive analysis of red fox urine marking rates, contributing to a greater understanding of territoriality and olfactory communication.
Article
Sexually experienced male rats display penile erections when exposed to faeces from mammalian females in oestrus (Rampin et al., Behav Brain Res, 172:169, 2006), suggesting that specific odours indicate female receptiveness across species. However, it is unknown to what extent the sexual response observed results from an odorous conditioning acquired during sexual experience. We tested the behavioural response of male Brown Norway rats both when sexually naïve and experienced to four odours, including oestrous rat faeces and 6-methyl-5-hepten-2-one (methylheptenone; a molecule found in higher concentrations during oestrus in female rats, foxes and horses). Odour had a significant effect on the sexual response of the naïve rats, with oestrus faeces provoking significantly more erections than herb odour, and with methylheptenone and di-oestrus faeces being intermediate. This indicates that sexually naïve male rats have an unconditioned ability to detect oestrous mediated via odour. After gaining sexual experience, the response to methylheptenone, di- and oestrus faeces was significantly higher than that observed with herb odour. These results strongly suggest that methylheptenone is part of the odorous bouquet of oestrus and contributes to the olfactory determination of female receptiveness.
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There are approximately 40-50 carotenoids in commonly consumed fruits and vegetables in a typical U.S. diet. These can be divided into carotenoid epoxides, mono- and dihydroxycarotenoids, hydrocarbon carotenoids, and carotenol acyl esters. However, among these, only a selected group of carotenoids are routinely found in human plasma, breast milk, major organs, and ocular tissues. In addition, several carotenoid metabolites have also been isolated and characterized from human plasma, tissues, and ocular tissues. The proposed metabolic transformation of carotenoids in humans will be discussed. Dietary carotenoids and their metabolites have been implicated in the prevention of cancer, cardiovascular dis- ease, and age-related macular degeneration (AMD). An approach for the development of a nutritional supplement that is based on the distribution of carotenoids and their metabolites in humans will be discussed.
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This paper describes a novel one-step synthesis of γ-lactones by the reaction of manganic and other higher valent metal carboxylates with readily available olefins and carboxylic acids. A free radical mechanism involving the selective generation and oxidation of organic free radicals is presented.
Article
More than 160 constituents were identified in a commercial Boronia absolute. The main constituents are β-ionone, (Z)-heptadec-8-ene, 8-hydroxylinalyl esters, methyl (Z,E)-4-(geranyloxy)cinnamates, methyl (Z,E)-4-(5-hydroxygeranyloxy)cinnamates, N-[2-(4-prenyloxyphenyl)ethyl]tiglamide and 3-hydroxymegastigm-7-en-9-one, which are even recognizable in the 400 MHz 1H-NMR spectrum of the dewaxed absolute.
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Carotenoids are one of the major food micronutrients in human diets and the overall objective of this review is to re-examine the role of carotenoids in human nutrition. We have emphasized the attention on the following carotenoids present in food and human tissues: β-carotene, β-cryptoxanthin, α-carotene, lycopene, lutein and zeaxanthin; we have reported the major food sources and dietary intake of these compounds. We have tried to summarize positive and negative effects of food processing, storage, cooking on carotenoid content and carotenoid bioavailability. In particular, we have evidenced the possibility to improve carotenoids bioavailability in accordance with changes and variations of technology procedures.
Article
Black-tailed deer (Odocoileus hemionus columbianus) discriminate between the geometric isomers of a lactone used as a pheromone by the species. They react strongly to (Z)-4-hydroxy-6-dodeceonic acid lactone, which occurs in their tarsal scent, but the response to theE isomer did not differ from the response to the solvent. The isomers were applied to one member of a group of freely interacting deer, and the sniffing, licking, and following responses were recorded. The synthesis of the geometric isomers of the lactone is described.
Article
Urine samples collected from dominant and subordinate male white-tailed deer during the breeding and nonbreeding season were analyzed by combined gas chromatography–mass spectrometry (GC-MS). Fifty-five volatiles were found in measurable quantities. Ketones were most numerous, followed by alcohols and alkanes. Nine compounds were common to both dominants and subordinates during the breeding season. Of these nine, three were present in higher concentrations in dominants, and six were higher in subordinates. During the breeding season, nine compounds were found exclusively in the urine of dominants, whereas 19 compounds were found exclusively in the urine of subordinates. Concentrations of several compounds were dependent on the time of year (breeding vs. nonbreeding season). Differences in compound presence and concentration may produce a rank-specific odor, although we suggest that differing concentrations of these suites of compounds may be more important for the identification of social status than the presence of individual compounds. Since mature male white-tailed deer urinate on their tarsal glands frequently during the breeding season, this behavior may allow a deer to simultaneously scent-mark its environment and carry intraspecific cues indicative of social status.
Article
The tail gland of canids is a hepatoid glandular organ surrounded and penetrated by powerful hair erector muscles squeezing out its lipoprotein secretion onto the skin surface. The gland is most developed in solitary species (Arctic, red, and corsac foxes) where it is represented by powerful glandular layer with large secretion containers—cisterns. It is less developed in the jackal; there are cisterns but glandular lobes do not merge into a layer. In the raccoon dog, wolf, and domestic dog the gland is composed of small lobes without cisterns. Hepatoid glands of the tail gland are represented by two histological variants distinguished by the presence or absence of hydrophobic lipids in the secretory cells. The excretory ducts are formed by lipid transformation of the cellular bands.
Article
Putrescine (1,4-diaminobutane) and cadaverine (1,5-di-aminopentane) were identified in the anal sac secretions of the red fox,Vulpes vulpes, and of the lion, Panthera leo. Anal sac secretion samples obtained over a period of 10 weeks by sampling from within each sac of each of 6 captive foxes were analyzed and putrescine, cadaverine, and volatile fatty acid compositions and secretion pH values recorded. A significant (P < 0.001)="" negative="" correlation="" of="" ph="" (range="" 6.5–9.4)="" with="" total="" volatile="" fatty="" acid="" concentration="" was="" observed.="" secretion="" compositions="" are="" discussed="" in="" the="" context="" of="" a="" fermentation="" hypothesis="" of="" chemical="" recognition.="" secretion="" samples="" could="" not="" be="" unambiguously="" assigned="" to="" particular="" foxes="" on="" the="" basis="" of="" simple="" comparisons="" of="" volatile="" fatty="" acid="" profiles="" alone.="" composition="" differences="" were="" noted="" between="" secretions="" obtained="" at="" a="" given="" time="" from="" corresponding="" right="" and="" left="">
Article
A control aqueous solution containing alcohol and polyethylene glycol, and a test solution with the addition of a mixture of eight volatile synthetic compounds identified in red fox urine, Were alternately placed on man-made mounds of fresh snow during January and February, the foxes' courtship season. The foxes preferentially marked those mounds treated with the test solution in the two experimental areas (P < 0.05 and <0.0001). It is concluded that one or more of the volatile substances induces mound marking in this species.
Article
The supracaudal gland of the red fox consists of both tubular apocrine sweat glands and massively developed sebaceous glands. The gland is characterized by a high level of histochemically demonstrable hydroxysteroid dehydrogenase activity (particularly -3 HSD) and by the presence of naturally fluorescent photolabile sebum constituents. Evidence suggests that these components may be carotenoid. Results are presented in the context of histological observations and are discussed in relation to scent production.
Chapter
The use of anomalous X-ray scattering of light elements like sulfur and phosphorus is of particular interest in biological structure research. These elements serve as native labels in proteins, nucleic acids and membranes. Their medium scattering power is drastically changed at their K absorption edges at wavelengths between 5 and 6 Å where X-ray absorption excludes the use of open air diffractometers. The construction of a new diffractometer tunable to wavelengths between 1.2 and 7 Å is presented. First results of anomalous scattering from sulfur in bacteriorhodopsin near the K absorption edge have been obtained recently. Their possible impact on crystallography will be considered. A comparison with nuclear spin dependent neutron scattering is given.
Article
Volatile organic compounds (VOCs) in fermented honeybush, Cyclopia subternata, were sampled by means of a high-capacity headspace sample enrichment probe (SEP) and analyzed by gas chromatography-mass spectrometry (GC-MS). Stereochemistry was determined by means of enantioselective GC-MS with derivatized β-cyclodextrin columns as chiral selectors. A total of 183 compounds, the majority of which are terpenoids (103; 56%), were identified by comparing their mass spectra and retention indices with those of reference compounds or tentatively identified by comparison with spectral library or literature data. Of these compounds, 37 were determined by gas chromatography-olfactometry (GC-O), using detection frequency (DF) and aroma extract dilution analysis (AEDA), to be odor-active (FD ≥ 2). (E)-β-Damascenone, (R/S)-linalool, (E)-β-damascone, geraniol, (E)-β-ionone, and (7E)-megastigma-5,7,9-trien-4-one were identified with the highest FD factors (≥512). The odors of certain compounds, that is, (6E,8Z)-megastigma-4,6,8-trien-3-one, (6E,8E)-megastigma-4,6,8-trien-3-one, (7E)-megastigma-5,7,9-trien-4-one, 10-epi-γ-eudesmol, epi-α-muurolol, and epi-α-cadinol, were perceived by GC-O assessors as typically honeybush-like.
Article
In humans, varying amounts of absorbed β-carotene are oxidatively cleaved by the enzyme β,β-carotene 15,15'-monooxygenase 1 (BCMO1) into two molecules of all-trans-retinal. The other carotenoid cleavage enzyme β,β-carotene 9',10'-dioxygenase (BCDO2) cleaves β-carotene at the 9',10' double bond forming β-apo-10'-carotenal and β-ionone. Although the contribution of BCDO2 to vitamin A formation has long been debated, BCMO1 is currently considered the key enzyme for retinoid metabolism. Furthermore, BCMO1 has limited enzyme activity towards carotenoids other than provitamin A carotenoids, whereas BCDO2 exhibits a broader specificity. Both enzymes are located at different sites within the cell, with BCMO1 being a cytosolic protein and BCDO2 being located in the mitochondria. Expression of BCMO1 in tissues other than the intestine has recently revealed its function for tissue-specific retinoid metabolism with importance in embryogenesis and lipid metabolism. On the other hand, biological activity of BCDO2 metabolites has been shown to be important in protecting against carotenoid-induced mitochondrial dysfunction. Single-nucleotide polymorphisms (SNPs) such as R267S and A379V in BCMO1 can partly explain inter-individual variations observed in carotenoid metabolism. Advancing knowledge about the physiological role of these two enzymes will contribute to understanding the importance of carotenoids in health and disease.
Article
This review focuses on plant carotenoids, but it also includes progress made on microbial and animal carotenoid metabolism to better understand the functions and the evolution of these structurally diverse compounds with a common backbone. Plants have evolved isogenes for specific key steps of carotenoid biosynthesis with differential expression profiles, whose characteristic features will be compared. Perhaps the most exciting progress has been made in studies of carotenoid cleavage products (apocarotenoids) with an ever-expanding variety of novel functions being discovered. This review therefore covers structural, molecular genetic and functional aspects of carotenoids and apocarotenoids alike. Apocarotenoids are specifically tailored from carotenoids by a family of oxidative cleavage enzymes, but whether there are contributions to their generation from chemical oxidation, photooxidation or other mechanisms is largely unknown. Control of carotenoid homeostasis is discussed in the context of biosynthetic and degradative reactions but also in the context of subcellular environments for deposition and sequestration within and outside of plastids. Other aspects of carotenoid research, including metabolic engineering and synthetic biology approaches, will only be covered briefly.
Article
Xanthophyll carotenoids, such as lutein, zeaxanthin and β-cryptoxanthin, may provide potential health benefits against chronic and degenerative diseases. Investigating pathways of xanthophyll metabolism are important to understanding their biological functions. Carotene-15,15'-monooxygenase (CMO1) has been shown to be involved in vitamin A formation, while recent studies suggest that carotene-9',10'-monooxygenase (CMO2) may have a broader substrate specificity than previously recognized. In this in vitro study, we investigated baculovirus-generated recombinant ferret CMO2 cleavage activity towards the carotenoid substrates zeaxanthin, lutein and β-cryptoxanthin. Utilizing HPLC, LC-MS and GC-MS, we identified both volatile and non-volatile apo-carotenoid products including 3-OH-β-ionone, 3-OH-α-ionone, β-ionone, 3-OH-α-apo-10'-carotenal, 3-OH-β-apo-10'-carotenal, and β-apo-10'-carotenal, indicating cleavage at both the 9,10 and 9',10' carbon-carbon double bond. Enzyme kinetic analysis indicated the xanthophylls zeaxanthin and lutein are preferentially cleaved over β-cryptoxanthin, indicating a key role of CMO2 in non-provitamin A carotenoid metabolism. Furthermore, incubation of 3-OH-β-apo-10'-carotenal with CMO2 lysate resulted in the formation of 3-OH-β-ionone. In the presence of NAD(+), in vitro incubation of 3-OH-β-apo-10'-carotenal with ferret hepatic homogenates formed 3-OH-β-apo-10'-carotenoic acid. Since apo-carotenoids serve as important signaling molecules in a variety of biological processes, enzymatic cleavage of xanthophylls by mammalian CMO2 represents a new avenue of research regarding vertebrate carotenoid metabolism and biological function.