Localized protein immobilization on microstructured polymeric surfaces for diagnostic applications

We demonstrate a localized protein immobilization method based on controlled physical adsorption on the three-phase boundary of an aqueous phase, a gas phase, and a polymeric material. By imprinting micrometer and sub-micrometer pillars onto a polymeric foil, superhydrophobic surfaces are fabricated. Those structures force the fluid locally into the Cassie–Baxter state and generate an artificial three-phase boundary at the edges of the imprinted pillars. First, fluorescence-labeled bovine serum albumin (BSA) and streptavidin dissolved in various buffer solutions are utilized to investigate protein adsorption on the structured surfaces. A stable adsorption of the respective protein on the three-phase boundary is observed. The following experiments use streptavidin adsorbed on the pillars to immobilize biotinylated antibodies for analyte detection. The pillars are passivated with an excess concentration of BSA to reduce nonspecific protein adsorption. Implemented in a lab-on-a-chip device, the proposed immobilization method is utilized in a sandwich assay to detect the inflammation marker C-reactive protein in human serum, showing the potential of this immobilization method for diagnostic applications. The method overcomes laborious procedures to immobilize proteins on thermoplastic materials, which enables the fast transfer of point-of-care applications from research to commercial scale.     

Foreign-language Skills in Rove-Beetles? Evidence for Chemical Mimicry of Ant Alarm Pheromones in Myrmecophilous <Emphasis Type="Italic">Pella</Emphasis> Beetles (Coleoptera: Staphylinidae)

By using chemical analyses, as well as laboratory and field behavioral tests, we tested the hypothesis that rove beetles of the myrmecophilous genus Pella use alarm pheromone compounds to avert attacks by their host ant Lasius fuliginosus. The secretions of Pella funestus and P. humeralis contain quinones and different aliphatic compounds, mainly undecane and 6-methyl-5-hepten-2-one (sulcatone). The latter two chemicals are also found in L. fuliginosus pheromone glands. Behavioral tests confirmed that undecane serves as an “aggressive alarm”-inducing pheromone in L. fuliginosus, whereas sulcatone most likely is a “panic-alarm”-inducing pheromone. The main tergal-secretion compounds, various quinones and undecane, individually and in mixtures induced aggression in L. fuliginosus workers. When sulcatone was added to these compounds, the space around the odor source was avoided and a reduced number of aggressive acts observed, suggesting that sulcatone blocks the aggression-inducing effect of undecane and the quinones. These results support the hypothesis that Pella beetles mimic alarm pheromones of their hosts. This is a rare example of chemical mimicry in myrmecophilous insects in which chemicals other than cuticular hydrocarbons are used.     

Specific foraging kairomones used by a generalist parasitoid

In general, it is assumed that generalist natural enemies do not innately use specific cues for the location of their host or prey species. This hypothesis was tested using naïve females of the generalist parasitoid Lariophagus distinguendus Förster and two of its hosts, larvae of the lesser grain borer Rhyzopertha dominica (F.) and of the granary weevil Sitophilus granarius L., feeding in wheat grains. In a four-chamber olfactometer, female parasitoids were attracted to volatiles emanating from the feces of both host species. Chemical analysis of the volatiles from the feces of R. dominica revealed the presence of dominicalure 1 and 2, the species specific aggregation pheromones of R. dominica. The main compounds in the volatiles from feces of S. granarius were identified as chemicals related to mites that are associated with hosts of L. distinguendus. Because these mites are not specific for S. granarius but also co-occur with other hosts, the mite chemicals have to be considered as general cues. In bioassays, synthetic dominicalure was attractive to naïve L. distinguendus, explaining the attraction of feces volatiles from R. dominica. Synthetic mite chemicals and sitophilate, the aggregation pheromone of S. granarius, had no effect on naïve parasitoids. It remains to be determined which innate chemical cues from feces of S. granarius are used by L. distinguendus. In contrast to our initial hypothesis, the generalist L. distinguendus is innately using specific cues for foraging. Two ideas are provided to explain this result.     

Sex Pheromone of the Rare Click Beetle <Emphasis Type="Italic">Betarmon bisbimaculatus</Emphasis>

The click beetle Betarmon bisbimaculatus (Fabricius, 1803) (Coleoptera: Elateridae) has a scattered distribution throughout a large area in Europe and the near East. Due to its scarcity, little is known about the ecology, biology, and development of this peculiar species. Here, we studied the composition of the female-released sex pheromone of B. bisbimaculatus. Neryl hexanoate, neryl octanoate, and neryl decanoate, in a ratio of approximately 3:1:6, were the only volatile compounds present in the extracts of pheromone glands. A synthetic mixture of all three compounds in the natural ratio was highly attractive to males in field traps. When the compounds were tested individually, only traps baited with neryl hexanoate were attractive, but they caught only a sixth of the males compared to the mixture. Based on the similarity of their sex pheromones, we propose that the tribe Pomachiliini with B. bisbimaculatus is closely related to the tribe Agriotini. This study shows the potential of sex pheromone studies for monitoring of rare and threatened insects as well as for elucidating phylogenetic relationships.     

Identification of the Sex Pheromone of Idolus picipennis (Bach, 1852) Revealed the Presence of a Cryptic Sibling Species

The click beetle Idolus picipennis represents the only species of its genus in Europe, where it is widely distributed but is rare and only occurs locally. In order to identify its sex pheromone we investigated gland extracts of females from populations in southern Germany. GC/MS analyses revealed two distinct types of gland compositions that correspond to slight but consistent morphological differences in the respective beetles. Extracts of one type contain four compounds, geranyl hexanoate (~ 40 %), (Z,E)-farnesyl hexanoate (~ 10 %), (E,E)-farnesyl hexanoate (~ 40 %), and (E,E)-farnesyl octanoate (~ 10 %), and this type belongs to the authentic I. picipennis (Bach 1852). Extracts of a second type contain neryl hexanoate (~10 %) and neryl octanoate (~ 90 %), and this type belongs to an Idolus species that apparently has been overlooked to date, presumably due to similarity with the authentic I. picipennis and insufficient material in collections. Synthetic blends of the identified compounds in their naturally-occurring ratios, as well as the main compounds alone, proved to be highly attractive to swarming males of the respective species in the field. A strong species-specific attraction also was observed in a locality where both species co-occur, thus confirming effective reproductive isolation. This study shows the potential of sex pheromones for monitoring rare and threatened insects as well as for detecting hitherto unknown cryptic species.     

Im Netz von Google. Web-Tracking und Datenschutz

Zusammenfassung  Webseiten-Betreiber haben zur bedarfsgerechten Gestaltung ihrer Dienste und nicht zuletzt vor dem Hintergrund neuer Marketing-Potentiale ein Interesse, Informationen über die Nutzung und die Besucher Ihrer Webseiten zu erhalten. Dabei k?nnen sie neben der Auswertung eigener Webserver-Protokolle auch auf verschiedene Web-Tracking-Dienste zurückgreifen. Der bekannteste und marktführende Web-Tracking-Dienst ist Google Analytics, der einem Webseiten-Betreiber kostenlos eine relativ detaillierte, grafisch aufbereitete Auswertung der Webseiten-Nutzung anbietet (siehe Lepperhoff/Petersdorf, DuD 4/2008). Google Analytics sammelt ohne explizite Einwilligung — und zumeist auch ohne Kenntnis — der Besucher einer Webseite verschiedene Informationen wie beispielsweise die besuchten Webseiten und die Besuchszeiten einer Session. Der nachfolgende Beitrag skizziert die Funktion typischer Web-Tracking-Dienste am Beispiel von Google Analytics und befasst sich mit der Frage, inwieweit die Nutzung solcher Services datenschutzrechtlich zul?ssig ist. Dr. Roland Steidle ist Rechtsanwalt bei Waldeck Rechtsanw?lte in Frankfurt am Main Dr. Ulrich Pordesch ist IT-Sicherheitskoordinator der Fraunhofer Gesellschaft e.V.     

Identification and biosynthesis of an aggregation pheromone of the storage mite Chortoglyphus arcuatus

In an effort to identify new pheromones from mites, the headspace of undisturbed colonies of the storage mite Chortoglyphus arcuatus was analyzed by GC-MS by use of a closed-loop stripping apparatus (CLSA) or solid-phase microextraction (SPME). The major compound emitted from the mites is (4R,6R,8R)-4,6,8-trimethyldecan-2-one (4R,6R,8R-8). The structure was elucidated by analysis of the mass spectrum, synthesis of authentic samples, and gas chromatography on a chiral phase. Bioassays show that this compound, for which we propose the trivial name chortolure, is an aggregation pheromone for both sexes of this species. Several related compounds are released in smaller amounts by the mites. The alarm pheromones of these mites, neral and geranial, can only be found in total extracts of the mites, in which 8 occurs only in minute amounts. The method of sampling is therefore crucial for pheromone identification. Feeding experiments with deuterated propionate showed that chortolure is a polyketide, formed by successive addition of four propionate units to an acetate starter.