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The neurotransmitter dopamine (DA) controls multiple behaviors and is perturbed in several major brain diseases. DA is released from large populations of specialized structures called axon varicosities. Determining the DA release mechanisms at such varicosities is essential for a detailed understanding of DA biology and pathobiology but has been limited by the low spatial resolution of DA detection methods. We used a near-infrared fluorescent DA nanosensor paint, adsorbed nanosensors detecting release of dopamine (AndromeDA), to detect DA secretion from cultured murine dopaminergic neurons with high spatial and temporal resolution. We found that AndromeDA detects discrete DA release events and extracellular DA diffusion and observed that DA release varies across varicosities. To systematically detect DA release hotspots, we developed a machine learning–based analysis tool. AndromeDA permitted the simultaneous visualization of DA release for up to 100 dopaminergic varicosities, showing that DA release hotspots are heterogeneous and occur at only ∼17% of all varicosities, indicating that many varicosities are functionally silent. Using AndromeDA, we determined that DA release requires Munc13-type vesicle priming proteins, validating the utility of AndromeDA as a tool to study the molecular and cellular mechanism of DA secretion.

Male ithomiine butterflies (Nymphalidae: Danainae) have hairpencils on the forewings (i.e., androconia) that disseminate semiochemicals during courtship. While most ithomiines are known to contain derivatives of pyrrolizidine alkaloids, dihydropyrrolizines, or γ-lactones in these androconia, here we report on a new class of fatty acid esters identified in two subspecies, Ithomia salapia aquinia and I. s. derasa. The major components were identified as isoprenyl (3-methyl-3-butenyl) (Z)-3-acetoxy-11-octadecenoate, isoprenyl (Z)-3-acetoxy-13-octadecenoate (12) and isoprenyl 3-acetoxyoctadecanoate (11) by GC/MS and GC/IR analyses, microderivatizations, and synthesis of representative compounds. The absolute configuration of 12 was determined to be R. The two subspecies differed not only in the composition of the ester bouquet, but also in the composition of more volatile androconial constituents. While some individuals of I. s. aquinia contained ithomiolide A (3), a pyrrolizidine alkaloid derived γ-lactone, I. s. derasa carried the sesquiterpene α-elemol (8) in the androconia. These differences might be important for the reproductive isolation of the two subspecies, in line with previously reported low gene exchange between the two species in regions where they co-occur. Furthermore, the occurrence of positional isomers of unsaturated fatty acid derivatives indicates activity of two different desaturases within these butterflies, Δ9 and Δ11, which has not been reported before in male Lepidoptera.

Male ithomiine butterflies (Nymphalidae: Danainae) have hairpencils on the forewings (i.e. androconia) that disseminate semiochemicals during courtship. While most ithomiines are known to contain derivatives of pyrrolizidine alkaloids, dihydropyrrolizines or g-lactones in these androconia, here we report on a new class of fatty acid esters identified in two subspecies, Ithomia salapia aquinia and I. s. derasa. The major components were identified as isoprenyl (3-methyl-3-butenyl) (Z)-3-acetyloxy-11-octadecenoate, isoprenyl (Z)-3-acetyloxy-13-octadecenoate (12) and isoprenyl 3-acetyloxyoctadecanoate (11) by GC/MS- and GC/IR-analyses, microderivatizations, and synthesis of representative compounds. The absolute configuration of 12 was determined to be R. The two subspecies differed not only in the composition of the ester bouquet, but also in the composition of more volatile androconial constituents. While some individuals of I. s. aquinia contained ithomiolide A, a PA derived g-lactone, I. s. derasa carried the sesquiterpene a-elemol in the androconia. These differences might be important for the reproductive isolation of the two subspecies, in line with previously reported low gene exchange between the two species in regions where they co-occur. Furthermore, the occurrence of positional isomers of unsaturated fatty acid derivatives indicates activity of two different desaturases within these butterflies, D9 and D11, which has not been reported before in male Lepidoptera.

Macrolides are a relatively common structural motif prevalent in Nature. However, the structures of these large ring lactones have been relatively difficult to elucidate via NMR spectroscopy due to the minute amounts of compounds that are sometimes obtainable from natural sources. Thus, GC-MS analysis of individual macrolactones has become the method of choice for the structural identification of these compounds. Here we discuss the mass spectrometric behavior of aliphatic macrolides, evaluating spectra from numerous compounds of various ring size, including derivatives containing methyl branches as well as double bonds. The specific fragmentation of these macrolactones under electron impact conditions allows for the development of a general rule set aimed at the identification of similar compounds by mass spectrometry. In addition, the mass spectra of dimethyl disulfide adducts of unsaturated macrolides are discussed. The mass spectra of almost 50 macrolides are presented.

International audience; Ithomiine butterflies use pyrrolizidine alkaloids (PAs) as precursors for malepheromones, such as dihydropyrrolizines or lactones. In contrast to most other ithomiine genera,none of these compounds have ever been detected in Oleria species. The absence of thesecompounds is thought to be the result of limited access to PA-containing plants. Here weinvestigate the contents of the androconia of Oleria onega caught in the wild when PA containingplants were abundant. Although the PA lycopsamine was detected in the hairpencils, none of theother known PA-derived compounds were present. Instead, the unsubstituted core of the PA necinebase, 1-methylene-1H-pyrrolizine (13), a very unstable compound, was found. The identity of thiscompound was proven by synthesis. Although its formation in nature appears very likely, 13 isalso formed during GC analysis of PAs, making its natural formation ambiguous. Nevertheless, itsreactivity makes it a good candidate for a signaling compound, because its rapid degradation canbe used for transporting spatial and time information. In addition, several other compounds, likelyused in intraspecific communication, were identified. All these compounds are reported for thefirst time as natural products or from insects. These include 9-hydroxynonanoic acid (21) and (Z)-9-hydroxy-6-enoic acid (18), as well as their condensation products with 11-hexadecenoic- andoctadecenoic acids. Furthermore, self-condensation products, such as (Z)-9-[(9-hydroxynon-6-enoyl)oxy]- and 9-[(9-hydroxynonanoyl)oxy]nonanoic acid and non-6-enoic acids (35, 36, 38, 40)were identified, together with the known compounds 2-heptadecanol (39) and 6,10,14-trimethylpentadecan-2-ol (37). In summary, O. onega appears to lack enzymes to producedihydropyrrolizines. In stark contrast to other ithomiine genera, a unique blend of oxidized fattyacids seems to be used instead.

Identifying the traits causing reproductive isolation and the order in which they evolve is fundamental to understanding speciation. Here, we quantify prezygotic and intrinsic postzygotic isolation among allopatric, parapatric, and sympatric populations of the butterflies Heliconius elevatus and Heliconius pardalinus. Sympatric populations from the Amazon (H. elevatus and H. p. butleri) exhibit strong prezygotic isolation and rarely mate in captivity; however, hybrids are fertile. Allopatric populations from the Amazon (H. p. butleri) and Andes (H. p. sergestus) mate freely when brought together in captivity, but the female F1 hybrids are sterile. Parapatric populations (H. elevatus and H. p. sergestus) exhibit both assortative mating and sterility of female F1s. Assortative mating in sympatric populations is consistent with reinforcement in the face of gene flow, where the driving force, selection against hybrids, is due to disruption of mimicry and other ecological traits rather than hybrid sterility. In contrast, the lack of assortative mating and hybrid sterility observed in allopatric populations suggests that geographic isolation enables the evolution of intrinsic postzygotic reproductive isolation. Our results show how the types of reproductive barriers that evolve between species may depend on geography.

Twenty-four strains of marine Roseobacter clade bacteria were isolated from macroalgae and investigated for the production of quorum-sensing autoinducers, N-acylhomoserine lactones (AHLs). GC/MS analysis of the extracellular metabolites allowed us to evaluate the release of other small molecules as well. Nineteen strains produced AHLs, ranging from 3-OH-C10:0-HSL (homoserine lactone) to (2E,11Z)-C18:2-HSL, but no specific phylogenetic or ecological pattern of individual AHL occurrence was observed when cluster analysis was performed. Other identified compounds included indole, tropone, methyl esters of oligomers of 3-hydroxybutyric acid, and various amides, such as N-9-hexadecenoylalanine methyl ester (9-C16:1-NAME), a structural analogue of AHLs. Several compounds were tested for their antibacterial and antialgal activity on marine isolates likely to occur in the habitat of the macroalgae. Both AHLs and 9-C16:1-NAME showed high antialgal activity against Skeletonema costatum, whereas their antibacterial activity was low.

Detection of neurotransmitters is an analytical challenge and essential to understand neuronal networks in the brain and associated diseases. However, most methods do not provide sufficient spatial, temporal, or chemical resolution. Near-infrared (NIR) fluorescent single-walled carbon nanotubes (SWCNTs) have been used as building blocks for sensors/probes that detect catecholamine neurotransmitters, including dopamine. This approach provides a high spatial and temporal resolution, but it is not understood if these sensors are able to distinguish dopamine from similar catecholamine neurotransmitters, such as epinephrine or norepinephrine. In this work, the organic phase (DNA sequence) around SWCNTs was varied to create sensors with different selectivity and sensitivity for catecholamine neurotransmitters. Most DNA-functionalized SWCNTs responded to catecholamine neurotransmitters, but both dissociation constants (Kd) and limits of detection were highly dependent on functionalization (sequence). Kd values span a range of 2.3 nM (SWCNT-(GC)15 + norepinephrine) to 9.4 μM (SWCNT-(AT)15 + dopamine) and limits of detection are mostly in the single-digit nM regime. Additionally, sensors of different SWCNT chirality show different fluorescence increases. Moreover, certain sensors (e.g., SWCNT-(GT)10) distinguish between different catecholamines, such as dopamine and norepinephrine at low concentrations (50 nM). These results show that SWCNTs functionalized with certain DNA sequences are able to discriminate between catecholamine neurotransmitters or to detect them in the presence of interfering substances of similar structure. Such sensors will be useful to measure and study neurotransmitter signaling in complex biological settings.

Neotropical Heliconius butterflies are members of various mimicry rings characterized by diverse colour patterns. In the present study we investigated whether a similar diversity is observed in the chemistry of volatile compounds present in male wing androconia. Recent research has shown that these androconia are used during courting of females. Three to five wild-caught male Heliconius individuals of 17 species and subspecies were analyzed by GC/MS. Most of the identified compounds originate from common fatty acids precursors, including aldehydes, alcohols, acetates or esters preferentially with a C18 and C20 chain, together with some alkanes. The compounds occurred in species-specific mixtures or signatures. For example, octadecanal is characteristic for H. melpomene, but variation in composition between the individuals was observed. Cluster analysis of compound occurrence in individual bouquets and analyses based on biosynthetic motifs such as functional group, chain length, or basic carbon-backbone modification were used to reveal structural patterns. Mimetic pairs contain different scent bouquets, but also some compounds in common, whereas sympatric species, both mimetic and non-mimetic, have more distinct compound compositions. The compounds identified here may play a role in mate choice thus helping maintain species integrity in a butterfly genus characterized by pervasive interspecific gene flow. © 2017, Springer Science+Business Media, LLC.

Single-walled carbon nanotubes (SWCNT) are versatile materials for imaging and sensing in the near infrared (nIR) range. Non-covalent adsorption with (bio)polymers such as ssDNA is a powerful approach to functionalize SWCNTs. This approach lead to sensors that detect the release of biomolecules such as neurotransmitters from cells with high spatiotemporal resolution. However, covalent approaches would be beneficial for many applications because of higher stability and photophysical signal transduction. It has been reported that reactions with diazonium salts create covalent defects and a red-shifted peak in the nIR fluorescence spectrum attributed to a formerly dark exciton. Here, we use defect chemistry to covalently modify SWCNTs and at the same time change their fluorescence spectrum in a well-defined way. For that purpose, we synthesized a maleimide-carrying diazonium salt and used a light-catalyzed reaction to introduce defects. The maleimide group can be further functionalized using thiols in a thiol-en click reaction. The modified SWCNTs were additionally wrapped in DNA for solubilization and characterized via nIR spectroscopy and atomic force microscopy (AFM). Our results show that depending on the attached thiol compound these SWCNTs respond differently to small molecules such as the neurotransmitter dopamine. This approach was then used to optimise the selectivity profile and sensitivity for fluorescent sensing applications. Furthermore, we covalently conjugated antibodies to the SWCNTs and used them for nIR labeling in cells. In summary, we present a new approach to covalently functionalize SWCNTs using defect chemistry and demonstrate applications in nIR imaging and sensing.

Content providers such as movie studios that embrace the Internet as an additional distribution channel are encountering the issue of measuring and managing intermedia effects. In multichannel distribution arrangements, content owners and distributors must know whether channels will cannibalize or complement one another and the circumstances under which such behavior will occur. With this knowledge, content providers can depart from merely describing cross-media effects and move toward managing cross-media. The authors present a five-step guide for measuring and managing cross-media effects on media content in multichannel distribution environments. The analytical framework builds on the ecological theory of the niche, which states that the intensity of intermedia competition depends on the degree of differentiation among channels. This framework is the first attempt to combine niche theory with conjoint analysis to develop a method of data collection and analysis. The use of the five-step guide is demonstrated with preference data from a quantitative survey of 552 potential consumers of digital movies. ACCESS TO FULL TEXT

Intercellular chemical communication proceeds with both spatial and temporal components. A very prominent example is neurotransmitter release from neurons. But so far there are no analytical tools available to detect release and propagation of signaling molecules on small length scales and fast time scales. We have developed fluorescent nanosensors to monitor interactions of cells with their environment e.g. for chemical imaging of small molecules released by cells. For that purpose we used near infrared (nIR) fluorescent single-walled carbon nanotubes (SWCNTs) and chemically rendered them selective for small signaling molecules such as the neurotransmitter dopamine. When dopamine binds the quantum yield of the sensors increased by up to 400 % and we were able to report single dopamine binding events. Parallel imaging of many of those sensors provides a nIR image (900 nm -1300 nm) of the dopamine concentration around cells. Furthermore, we used a stochastic kinetic Monte-Carlo simulation to predict the collective image of many sensors and how on and off rate constants affect the spatial and temporal resolution of this approach. This technique was used to image hot spots and directionality of dopamine release from neurons and other cells. We observed localized, unlabeled release sites that correlate with membrane curvature and cell morphology. We furthermore tailored SWCNTs to bind cell surface receptors such as integrins to monitor and investigate cell adhesion and migration on surfaces. These results illustrate how to use fluorescent nanosensors for quantitative chemical imaging of complex biological processes.

While the evolving information society is freely opening and sharing its diaries, social networks and source codes, it remains to be seen if the same will come true for scientific knowledge. Despite strong sympathy for the idea, scientists balk at Open Access publishing. Here we shed some light on why this is so.

Robert G. Picard ist in der Medienbranche eine eigene Marke. Ob Who's Who in America, Who's Who in der Welt oder Who's Who in der Bildung: An Picard kommt niemand vorbei. Er gilt als einer der weltweit führenden Experten für Medienwirtschaft und Kommunikationspolitik. Er ist Professor für Volkwirtschaftslehre und Direktor des Media Management and Transformation Centre an der Jönköping International Business School der Universität Jönköping in Schweden.

Sie ist als „Lady in Red“ bekanntgeworden. Ob früher VOX oder jetzt RTL: Passend zur Unternehmensfarbe trägt die mächtigste Frau in der deutschen Fernsehlandschaft, Anke Schäferkordt, auch heute noch gern rot. Den roten Teppich jedoch meidet sie, wenn möglich. Schäferkordt steht trotz ihrer Position nicht gerne im Rampenlicht. Seit über vier Jahren leitet die 46-Jährige erfolgreich die Mediengruppe RTL Deutschland, zu der unter anderem die Sender RTL Television, VOX und n-tv gehören sowie Anteile an RTL II oder Super RTL, aber auch Unternehmen wie RTL interactive, der Werbezeitenvermarkter IP Deutschland, die Nachrichteneinheit infonetwork oder als technischer Dienstleister der gesamten Gruppe die CBC. Zugleich ist sie Geschäftsführerin des Fernsehsenders RTL Television.

Unternehmen der Medien-, Telekommunikations- sowie der Softwarebranche vereinigen einen immer größeren Teil des Bruttoinlandsprodukts auf sich und erleben gleichzeitig – wie kein anderes Segment – Veränderungen ihrer Geschäftsgrundlagen durch die Digitalisierung. Aufgrund ihres prägenden Einflusses auf viele andere Branchen sind sie von strategischer Bedeutung für die gesamte Volkswirtschaft und stellen eines der wichtigsten Felder für Innovation und Neugründung dar. Dies eröffnet Absolventen mit entsprechendem Studienschwerpunkt sowohl national als auch international hervorragende Beschäftigungschancen. Die Ludwig-Maximilians-Universität München (LMU) hat daher als erste Universität im deutschsprachigen Raum zum Wintersemester 2007/08 in ihren betriebswirtschaftlichen Studiengängen einen breit angelegten, wissenschaftlich fundierten und vorwiegend branchenorientierten Studienschwerpunkt „Digitale Ökonomie“ aufgebaut.

A new arabinomannan has been isolated from the cell wall of the green algae Chlorella vulgaris by extraction with 0.1 M NaOH, dialysis and SEC fractionation. M w was about 8000 u. Terminal, 2- and 5-O-linked arabinofuranosyl residues, and 2,6-O-linked mannopyranosyl residues were detected as the main constituents beside some minor mannose components by methylation analysis. Electrospray ionisation mass spectrometry (ESI–MS) with collision induced dissociation (CID) up to MS 3 experiments of oligosaccharides obtained by partial methanolysis or partial acid hydrolysis indicated the presence of Man→Man- and Ara→Ara- as well as Ara→Man- and also Man→Ara-sequences. MS 2 experiments gave evidence of a (1→6)-linked mannan, probably also including some (1→2)-linked mannosyl and 5-linked arabinofuranosyl residues. Mannooligosaccharides up to DP5 with mainly (1→6)-, but at higher DP also (1→2)-linkages were obtained by acid hydrolysis, and arabino oligomers up to DP4 could be detected after mild methanolysis. In accordance with results from methylation analysis and ESI–MS/CID t -β-Ara f , 2-α-Ara f , 5-α-Ara f and 2,6-α-Man p were identified from homo- and heteronuclear 1D- and 2D NMR experiments in a molar ratio of ∼2:2:1:2. A highly branched structure is suggested with a 6- and 2-O-linked mannan main chain, comprising 5-Ara f residues. Ara f -β-[(1→2)-Ara f -α-(1→] n side chains with an average chain length of 2 are linked to the mannan main chain. The configuration of Ara is d . The new polysaccharide shows structural similarities with the (lipo)arabinomannans of Mycobacterium tuberculosis .