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Krimmel B.,University of Vienna | Swoboda F.,University of Vienna | Solar S.,University of Vienna | Reznicek G.,Althanstrasse
Radiation Physics and Chemistry | Year: 2010

The OH-radical induced degradation of hydroxybenzoic acids (HBA), hydroxycinnamic acids (HCiA) and methoxylated derivatives, as well as of chlorogenic acid and rosmarinic acid was studied by gamma radiolysis in aerated aqueous solutions. Primary aromatic products resulting from an OH-radical attachment to the ring (hydroxylation), to the position occupied by the methoxyl group (replacement -OCH3 by -OH) as well as to the propenoic acid side chain of the cinnamic acids (benzaldehyde formations) were analysed by HPLC-UV and LC-ESI-MS. A comparison of the extent of these processes is given for 3,4-dihydroxybenzoic acid, vanillic acid, isovanillic acid, syringic acid, cinnamic acid, 4-hydroxycinnamic acid, caffeic acid, ferulic acid, isoferulic acid, chlorogenic acid, and rosmarinic acid. For all cinnamic acids and derivatives benzaldehydes were significant oxidation products. With the release of caffeic acid from chlorogenic acid the cleavage of a phenolic glycoside could be demonstrated. Reaction mechanisms are discussed. © 2010 Elsevier Ltd.


Pelvicachromis sacrimontis Paulo, 1977 was originally described on the basis of an iconotype in an aquarium journal. Herein, the validity of the name as well as the species status is discussed, an updated diagnosis and description of the species is given, and a neotype and a series of paraneotypes is designated. The species differs from congeners in a combination of coloration features including a broad dark midlateral band, the absence of blue and reddish dots in the caudal fin of males, and the specific coloration of the dorsal fin in females. Copyright © 2012 Magnolia Press.


The twist-necked turtle (Platemys platycephala, Schneider 1792) is the only member of the genus Platemys. Despite a pan-Amazonian distribution in South America, ecology and population status of this small, forest-dwelling species are unknown in many countries within its range. Currently it is not listed in the IUCN Red List of Threatened Species, and there are almost no published data on reproduction, feeding, or habitat preferences in the wild. In this article, observations on habitat selection, short-term movements and feeding in the Nouragues Field Reserve, French Guyana, are reported for the first time. Study specimens used the same areas in the late rainy season of 2009 and 2010, moving total distances of 503-686 m over a period of approximately 3 wk within calculated areas of activity ranging in size between 0.73 and 1.59 ha. The main habitats used were palm swamps, temporary flooded forest, and primary nonflooded forest. The analysis of 4 stomach and 2 fecal samples showed that different classes of insects, worms and crustaceans as well as amphibian eggs were consumed as food items. © 2013 Chelonian Research Foundation.


Sixty-six specimens of seven populations of the Pelvicachromis taeniatus-group are compared and examined, using molecular and anatomical-morphological methods as well as coloration patterns. Accordingly, the taxon P. taeniatus is restricted to populations from Benin and Nigeria. For most populations from Cameroon the old taxon P. kribensis is revalidated and specimens from the Wouri River are described as a new species, P. drachenfelsi sp. nov. Species diagnosis is based on molecular characters and coloration patterns - mainly in the coloration of the male caudal fin. Pelvicachromis drachenfelsi sp. nov. shares a black margin and white to pale bluish submargin in the lower half of the male caudal fin with P. taeniatus, a coloration pattern absent in P. kribensis, but it differs from P. taeniatus by a white margin and a black submargin in the dorsal half of this fin (vi a pattern of dots in P. taeniatus). Additionally, female of P. taeniatus differ from those of P. drachenfelsi sp. nov. and P. kribensis by two or three horizontal dark bars in the caudal fin (vs none in P. drachenfelsi sp. nov. and one in most populations of P. kribensis). The populations of P. kribensis from the Moliwe River system and the Nyong River system potentially represent a new species, but a definitive decision requires additional material and study. The molecular phylogeny points to the possibility that Pelvicachromis is not monophyletic.


Hoeschele M.,Althanstrasse | Fitch W.T.,Althanstrasse
Animal Cognition | Year: 2016

Metrical phonology is the perceptual “strength” in language of some syllables relative to others. The ability to perceive lexical stress is important, as it can help a listener segment speech and distinguish the meaning of words and sentences. Despite this importance, there has been little comparative work on the perception of lexical stress across species. We used a go/no-go operant paradigm to train human participants and budgerigars (Melopsittacus undulatus) to distinguish trochaic (stress-initial) from iambic (stress-final) two-syllable nonsense words. Once participants learned the task, we presented both novel nonsense words, and familiar nonsense words that had certain cues removed (e.g., pitch, duration, loudness, or vowel quality) to determine which cues were most important in stress perception. Members of both species learned the task and were then able to generalize to novel exemplars, showing categorical learning rather than rote memorization. Tests using reduced stimuli showed that humans could identify stress patterns with amplitude and pitch alone, but not with only duration or vowel quality. Budgerigars required more than one cue to be present and had trouble if vowel quality or amplitude were missing as cues. The results suggest that stress patterns in human speech can be decoded by other species. Further comparative stress-perception research with more species could help to determine what species characteristics predict this ability. In addition, tests with a variety of stimuli could help to determine how much this ability depends on general pattern learning processes versus vocalization-specific cues. © 2016, The Author(s).


God R.,University of Vienna | Kurzweil J.,Althanstrasse | Klotzli U.,University of Vienna
Mineralogy and Petrology | Year: 2016

The study focuses on a subvolcanic rhyodacite dyke intruding a fine grained biotite granite and paragneisses of the South Bohemian Massif, part of the Variscan Orogenic Belt in Central Europe. The subvertical dyke strikes NNE, displays a thickness of about 30 m and has been traced by boulder mapping for approximately 7 km. The rhyodacites have been affected by two hydrothermal fluids. An older one of oxidizing condition giving rise to a reddish to brownish type of rock (Type I) and a younger fluid of reducing condition causing a greenish variety (Type II). The hydrothermal alteration is associated with the formation of the clay minerals chlorite, sericite, kaolinite and smectite and a disseminated pyrite mineralization. Bulk chemistries of the rhyodacites emphasize the hydrothermal alterations to be isochemical with the exception of sulphur enriched up to a maximum of 0.6 wt%. Trace element composition of the rhyodacites points to a barren geochemical environment in terms of base and precious elements. Sulphur isotope investigations of pyrites from the rhyodacites and the hosting granites respectively yield d34S data ranging from +0.07 to −2.22 ‰, emphasizing a magmatic origin of the sulphur. Geochronological investigations yield in situ U/Pb zircon ages of 312 ± 4 Ma for the biotite granite and of 292 ± 4 Ma for the rhyodacitic dykes indicating a time gap of ≈ 20 Ma between these two intrusive events. A contemporaneous but geochemically specialized granitic intrusion associated with NW striking “felsitic” dykes occurs about 10 to 20 km to the NW of Arnolz. However, the rhyodacites around Arnolz differ significantly from these felsitic dykes in their geochemistry and alteration phenomena which points to a different magmatic source. This coincides with a change in the orientation of the dykes from a NW direction controlling the geochemically specialized intrusions in the NW to a dominating NNE direction mirrored by the studied rhyodacites at Arnolz. © 2016 The Author(s)


Neudorfer C.,Medical University of Vienna | Shanab K.,Althanstrasse | Holzer W.,Althanstrasse | Rami-Mark C.,Medical University of Vienna | And 3 more authors.
MolBank | Year: 2015

Starting from jV-methyl-l-{(35',45')-4-[2-(trifluoromethyl)phenoxy]-3,4-dihydro-l//-isochromen-3-yl}methanamine (1) target compound 2 is prepared using a mild, direct alkylation approach with 2-fluoroethyl trifluoromethanesulfonate. © 2015 by the authors; licensee MDPI, Basel, Switzerland


The diversity, abundance and habitat of breeding raptors in the Austrian March floodplain forests, located in the border area between Austria, Slovakia and the Czech Republic, were studied in 2008. The study area (19.7 km?) had not been explored by ornithologists until the 1990s due to the considerable flood dynamics and the subsequent limited accessibility. The present field study was performed between January and July 2008 between Hohenau and Drösing (Lower Austria), consisting of two reference areas of comparable size but with different cultivation techniques, i.e. the high forest cultivation in the North (960 ha) and the middle forest cultivation in the South (1010 ha). Additionally, the field study was conducted to explore the influence of the vegetation structure around the nesting site (microhabitat, r=15 m, 706.5 m 2) and the landscape characteristics (macrohabitat, r=250 m, 19.6 ha) on the habitat choices of birds of prey. To get a representative sample for comparison, the same data were collected at 50 randomly selected sites. Aeries were mapped along transects between 50 m intervals, and 167 were found in total. 57 out of 167 aeries were occupied by birds of prey. In total, nine breeding raptor species were recorded. The most abundant species was the Common Buzzard (Buteo buteo), occupying 34 aeries, followed by the Marsh Harrier (Circus aeroginosus) with five or six pairs. The Red Kite (Milvus milvus) population, with a quantity of three pairs was remarkable on a national scale. The Black Kite (Milvus migrans) (three pairs), the Honey Buzzard (Pernis apivorus) (three pairs), the Goshawk (Accipiter gentilis) (three pairs), the Kestrel (Falco tinnunculus) (two pairs) and the Hobby (Falco subbuteo) (two pairs) also bred in the study area. Since 2002 the White-tailed Eagle (Haliaeetus albkiUa) has bred successfully in the floodplains. The Sparrowhawk (Accipiter nisus), the Saker Falcon (Falco cherrug) and the Imperial Eagle (Aquila heliaca) were not found as breeders in the study area, but were known to breed nearby. The results indicated a population growth of the Common Buzzard, whereas the density of other predatory birds has been steady for the last 15 years. The density is high compared to other places in central Europe, including the Danube floodplains in Austria. Besides, the density seems to be independent from the type of cultivation. The data concerning the habitat structure were analyzed in a Geographic Information System (GIS) and indicate the March flood-plain forests as very attractive for raptors. The investigation area offers a varied and structured landscape with abundant waterbodies and meadows. Predatory birds prefer old growth trees, particularly oaks (Quercus sp.) and poplars (Populus sp.) for nesting. These types of trees are numerous in middle forest cultivation. Additionally, a higher number of older aeries can be found there compared to high forest cultivations. Birds of prey prefer a distinctive forest structure with plenty of deadwood, far away from paths or protected by dense shrub and undergrowth. Therefore, the conservation of mature forests, the reduction of human disturbance and the reactivation of the flood dynamics could have a positive effect on the raptor population in the long term. © IfV, MPG 2010.


News Article | March 21, 2016
Site: phys.org

Chemists from the University of Vienna around Annette Rompel have analysed the structure of the enzyme in the leaves of Coreopsis. Credit: Annette Rompel What is it that walnut leaves, mushrooms and Coreopsis have in common? An enzyme that is also responsible for the browning reaction in bananas or apples is present in all of them in large amounts. For the first time, chemists from the University of Vienna around Annette Rompel have analyzed the structure of the enzyme in the leaves of Coreopsis. Who doesn't know the brown colour of a sliced apple or overripe fruit? Annette Rompel, Head of the Department of Biophysical Chemistry at the University of Vienna, knows this phenomenon very well. Since more than 20 years, she has studied the tyrosinase, an enzyme that does not only exist in plants but also makes the human skin become brown. The "browning" is caused by a number of complex polyphenols. These are secondary plant metabolites that occur, e.g. as health-promoting colouring and flavouring components. Tyrosinase, in turn, is a metal-containing enzyme that catalyses the hydroxylation and oxidation of phenols. "And this is the reason for the discolouration", explains the chemist. In addition to tyrosinase, a second enzyme called catechol oxidase is capable of oxidising diphenols such as catechol. "Thus, both enzymes are responsible for the browning reaction", says Rompel. The first author Christian Molitor stresses: "The actual physiological role of the enzymes in various cells as well as their natural substrates are still largely unknown." The chemists have addressed this question. Having successfully characterised the enzymes in mushrooms and walnut leaves, the researchers now focus on another plant: Coreopsis—a popular garden plant whose flowers resemble those of sunflowers with their radiant yellow blossoms also found in the University's greenhouse in Althanstrasse. "This is mainly due to the excellent work of the gardeners Thomas Joch and Andreas Schröfl", says Rompel who praises the employees "with the green thumb". Where does the yellow colour come from? "We have chosen Coreopsis for our research, because the "browning enzyme" is found in the petals in high concentrations", says the chemist. The enzyme—in this case a catechol oxidase—is responsible for the conversion of certain flower pigments. "Since the petal dyes are called aurones, the enzyme received the name aurone synthase", explains the chemist. A new classification must be defined Her team comprising Christian Molitor, Stephan Mauracher and Cornelia Kaintz managed to characterise this enzyme for the first time: In the paper recently published in PNAS, the researchers presented the first crystal structure of aurone synthase in both a latent and an active form. "In a third step, we had an inactive form (through sulfonation) isolated and crystallised", says Molitor, adding: "With regard to the crystal structures of the latent, active and inactive form we achieved results that provide further insight into the complex mechanism of activation." With their work, the researchers from the University of Vienna also describe a new mechanism for the catalytic cycle of plant polyphenol oxidases, i.e. the "browning process" in plants. "Our results show that the general classification of tyrosinase and catechol oxidase must be reconsidered", says first author Molitor. The research results could lead to applications in various disciplines, among others in biotechnological, pharmaceutical or agricultural processes. "Based on our results, you could—by controlling the enzymes —, for example, increase the content of bioactive substances in fruit and vegetables", explains Rompel and smiles: "Fruit and vegetables would then become even healthier." Explore further: No need to get browned off: Edible films keep fruit fresh More information: Christian Molitor et al. Aurone synthase is a catechol oxidase with hydroxylase activity and provides insights into the mechanism of plant polyphenol oxidases, Proceedings of the National Academy of Sciences (2016). DOI: 10.1073/pnas.1523575113


News Article | March 21, 2016
Site: www.rdmag.com

Who doesn't know the brown color of a sliced apple or overripe fruit? Annette Rompel, Head of the Department of Biophysical Chemistry at the University of Vienna, knows this phenomenon very well. Since more than 20 years, she has studied the tyrosinase, an enzyme that does not only exist in plants but also makes the human skin become brown. The "browning" is caused by a number of complex polyphenols. These are secondary plant metabolites that occur, e.g. as health-promoting coloring and flavoring components. Tyrosinase, in turn, is a metal-containing enzyme that catalyses the hydroxylation and oxidation of phenols. "And this is the reason for the discolouration", explains the chemist. In addition to tyrosinase, a second enzyme called catechol oxidase is capable of oxidising diphenols such as catechol. "Thus, both enzymes are responsible for the browning reaction", said Rompel. The first author Christian Molitor stresses: "The actual physiological role of the enzymes in various cells as well as their natural substrates are still largely unknown." The chemists have addressed this question. Having successfully characterized the enzymes in mushrooms and walnut leaves, the researchers now focus on another plant: Coreopsis -- a popular garden plant whose flowers resemble those of sunflowers with their radiant yellow blossoms also found in the University's greenhouse in Althanstrasse. "This is mainly due to the excellent work of the gardeners Thomas Joch and Andreas Schröfl", said Rompel who praises the employees "with the green thumb". Where does the yellow color come from? "We have chosen Coreopsis for our research, because the "browning enzyme" is found in the petals in high concentrations", said the chemist. The enzyme -- in this case a catechol oxidase -- is responsible for the conversion of certain flower pigments. "Since the petal dyes are called aurones, the enzyme received the name aurone synthase", explains the chemist. A new classification must be defined Her team comprising Christian Molitor, Stephan Mauracher and Cornelia Kaintz managed to characterize this enzyme for the first time: In the paper recently published in PNAS, the researchers presented the first crystal structure of aurone synthase in both a latent and an active form. "In a third step, we had an inactive form (through sulfonation) isolated and crystallised", said Molitor, adding: "With regard to the crystal structures of the latent, active and inactive form we achieved results that provide further insight into the complex mechanism of activation." With their work, the researchers from the University of Vienna also describe a new mechanism for the catalytic cycle of plant polyphenol oxidases, i.e. the "browning process" in plants. "Our results show that the general classification of tyrosinase and catechol oxidase must be reconsidered", said first author Molitor. The research results could lead to applications in various disciplines, among others in biotechnological, pharmaceutical or agricultural processes. "Based on our results, you could -- by controlling the enzymes --, for example, increase the content of bioactive substances in fruit and vegetables", explains Rompel and smiles: "Fruit and vegetables would then become even healthier."

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