Identification of Cuticular and Web Lipids of the Spider Argiope bruennichi

Emerging evidence shows that the cuticular and silk lipids of spiders are structurally more diverse than those of insects, although only a relatively low number of species have been investigated so far. As in insects, such lipids might play a role as signals in various contexts. The wasp spider Argiope bruennichi has probably the best investigated chemical communication system within spiders, including the known structure of the female sex pheromone. Recently we showed that kin-recognition in A. bruennichi could be mediated through the cuticular compounds consisting of hydrocarbons and, to a much larger proportion, of wax esters. By use of mass spectrometry and various derivatization methods, these were identified as esters of 2,4-dimethylalkanoic acids and 1-alkanols of varying chain lengths, such as tetradecyl 2,4-dimethylheptadecanoate. A representative enantioselective synthesis of this compound was performed which proved the identifications and allowed us to postulate that the natural enantiomer likely has the (2R,4R)-configuration. Chemical profiles of the silk and cuticular lipids of females were similar, while male cuticular profiles differed from those of females. Major components of the male cuticular lipids were tridecyl 2,4-dimethyl-C17-19 alkanoates, whereas those of females were slightly longer, comprising tridecyl 2,4-dimethyl-C19-21 alkanoates. In addition, minor female-specific 4-methylalkyl esters were detected.

Suitable Areas for Apiculture Expansion Determined by Antioxidant Power, Chemical Profiles, and Pesticide Residues in Caldcluvia paniculate Honey and Beeswax Samples

Forty-two samples of Tiaca Honey (Caldcluvia paniculata) obtained from beehives belonging to 14 apiaries (three honey samples per apiary) were collected at the end of January near Osorno (40°34′ S, 73°8′ W), Puyehue (40°40′ S, 72°37′ W) and Frutillar 41°7′ S, 72°59′ W) covering an area of 1240 km2. They presented the highest phenol contents (0.36 mg gallic acid equivalent/kg) and antioxidant power (1.27 mM equivalent of Fe+2/g of sample), and were among the highest for antiradical activity. Phenol contents and antioxidant power (r = 0.72, p-value < 0.01) and total phenol contents and antiradical activity (r = 0.69; p-value < 0.01) displayed linear correlations. Only two beeswax samples showed residues of the pesticide fenhexamid. The respective sites (Purranque [40°55′ S, 73°10′ W] and Coligual [40°49′ S, 72°54′ W]) were the only areas located near active farms. Additionally, the m/z value 163.1091 was found as an element to identify honeys. Data were used to construct a mapped suitability index ranking for pesticide-free areas with high biological quality. The provided chemical profiles will aid local beekeepers in obtaining international certifications, particularly for the EU market. In turn, the constructed maps indicate suitable areas for apiculture expansion, while differentiated pesticide detection in honey and beeswax requires further comparative research.

Flavor Chemical Profiles of Cabernet Sauvignon Wines: Six Vintages from 2013 to 2018 from the Eastern Foothills of the Ningxia Helan Mountains in China

The eastern foothills of the Helan Mountains in the Ningxia region (Ningxia), is a Chinese wine-producing region, where Cabernet Sauvignon is the main grape cultivar; however, little compositional or flavor information has been reported on Ningxia wines. Oenological parameters, volatile profiles, and phenolic profiles were determined for 98 Ningxia Cabernet Sauvignon wines from the 2013–2018 vintages, as well as 16 from Bordeaux and California, for comparison. Ningxia wines were characterized by high ethanol, low acidity, and high anthocyanin contents. Multivariate analysis revealed that citronellol and 12 characteristic phenolic compounds distinguish Ningxia wines from Bordeaux and California wines. The concentrations of most phenolic compounds were highest in the 2018 Ningxia vintage and decreased with the age of the vintage. To our knowledge, this is the first extensive regionality study on red wines from the Ningxia region.

Diversity and Divergence: Evolution of defense chemistry in the tropical tree genus Inga

Plants are widely recognized as chemical factories, with each species producing dozens to hundreds of unique secondary metabolites. These compounds shape the interactions between plants and their natural enemies. Here we explore how plants generate chemical diversity, and what evolutionary processes have led to novel compounds and unique chemical profiles. We comprehensively characterized the chemical profile of one-third of the species of tropical rainforest trees in the genus Inga (~ 100, Fabaceae) and applied phylogenetic comparative methods to understand the mode of chemical defense evolution. We show that: 1) Each Inga species produces exceptionally high levels of phytochemical diversity, despite costs, tradeoffs and biosynthetic constraints. 2) Closely related species have highly divergent defense profiles, with individual compounds, major compound classes and complete profiles showing little to no phylogenetic signal. 3) We show that the evolution of a species' chemical profile shows a signature of divergent adaptation, implying that it is advantageous for a species to have distinct chemistry from close relatives to avoid shared natural enemies. 4) Finally, we hypothesize a model where deep homology of biosynthetic pathways and rapid changes in regulatory mechanisms may better explain the observed large shifts in defense chemicals between closely related taxa.

Chemical Characteristics and Antioxidant Activity of Arctostaphylos uva-ursi L. Spreng. at the Southern Border of the Geographical Range of the Species in Europe

The bearberry (Arctostaphylos uva-ursi L. Spreng.) is a source of herbal material—bearberry leaf (Uvae ursi folium), which is highly valued and sought by pharmaceutical and cosmetic industries. For many years, leaves of this plant have been used in traditional medicine as a diuretic, antimicrobial, and anti-inflammatory agent for various diseases of the urogenital tract. The bearberry has also been proposed as a natural antioxidant additive due to the high contents of phenolic compounds in its leaves. The study was focused on characterization of the basic phytochemical composition and antioxidant activity of extracts derived from bearberry leaves collected from plants located at the southern border of the geographical range of the species in Europe. The investigated herbal material is characterized by a different chemical profile compared to the chemical profiles of bearberry found in other parts of the continent. Bearberry extracts from plants growing in two different habitat types—heathlands and pine forests showed a wide range of variation, especially in the concentration of hyperoside, corilagin, and methylartutin and the total flavonoid contents. In addition to arbutin, bearberry can be a valuable source of phenolic compounds, which are mainly responsible for the antioxidant properties of extracts. The high content of phenols and high values of antioxidant parameters indicate a high potential of bearberry leaves to be used as a powerful natural source of antioxidants in herbal preparations. Therefore, the A. uva-ursi populations can be a source of plant material for pharmaceutical, cosmetic, and food industries.

Asymmetric Interfacial Intermixing Associated Magnetic Coupling in LaMnO3/LaFeO3 Heterostructures

The structural and magnetic properties of LaMnO3/LaFeO3 (LMO/LFO) heterostructures are characterized using a combination of scanning transmission electron microscopy, electron energy-loss spectroscopy, bulk magnetometry, and resonant x-ray reflectivity. Unlike the relatively abrupt interface when LMO is deposited on top of LFO, the interface with reversed growth order shows significant cation intermixing of Mn3+ and Fe3+, spreading ∼8 unit cells across the interface. The asymmetric interfacial chemical profiles result in distinct magnetic properties. The bilayer with abrupt interface shows a single magnetic hysteresis loop with strongly enhanced coercivity, as compared to the LMO plain film. However, the bilayer with intermixed interface shows a step-like hysteresis loop, associated with the separate switching of the “clean” and intermixed LMO sublayers. Our study illustrates the key role of interfacial chemical profile in determining the functional properties of oxide heterostructures.