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Development of a Basic Biosensor System for Wood Degradation using Volatile Organic Compounds
No full textAssessment of fungivorous insect antennae as biosensors for detecting wood rotting fungi
No full textAssessment of fungivorous insect antennae as biosensors for detecting wood rotting fungi
No full textAntennal and Behavioral Responses of Cis boleti to Fungal Odor of Trametes gibbosa
No full textCis boleti (Coleoptera: Ciidae) preferentially colonizes fungi from the genus Trametes that are known as important wood decomposers. The aim of our research was to investigate if C. boleti uses the chemical volatile composition of its fungal host, Trametes gibbosa, as a key attraction factor. Therefore, the T. gibbosa fruiting body volatiles were analysed by using gas chromatography-mass spectrometry, with parallel electroantennographic detection (GC-MS/EAD) using adults of C. boleti. Furthermore, we examined the behavioral responses of C. boleti to the T. gibbosa volatile compounds. The dominant component of the T. gibbosa fruiting body bouquet was 1-octen-3-ol. Other volatiles, like the aldehydes hexanal, nonanal, and (E,E)-2,4-decadienal and the terpene alpha-bisabolol, were present in minor quantities. 1-Octen-3-ol was released with a ratio of the (R)- and (S)-enantiomers of 93:7, respectively. Electroantennography (EAG) employing C. boleti antennae yielded consistently dominant responses to 1-octen-3-ol. GC-EAD and EAG responses to pure standard compounds showed that C. boleti also perceived other host fungal volatiles. A highly significant attraction to 1-octen-3-ol was observed in behavioral tests. Female beetles were significantly attracted to the (S)-(+)- enantiomer at 10 times lower doses than male beetles. Our finding is the first direct proof that ciid beetles use 1-octen-3-ol as a key cue for host finding
Development of a Basic Biosensor System for Wood Degradation using Volatile Organic Compounds
Get PDFDie Prüfung von Holz und ein Test seiner Beständigkeit gegen Mikroorganismen wie Pilze spielen eine wichtige Rolle in der Forstwirtschaft und der holzverarbeitenden Industrie. Um solche Prüfungen zu erleichtern und präzise Bewertungen zu ermöglichen, ist eine effiziente Testmethode erforderlich. Flüchtige organische Verbindungen (volatile organic compounds VOCs), die vom Holzsubstrat und vom pilzlichen Metabolismus erzeugt werden, sind Marker für den Zustand des Holzes, d.h. sie zeigen Art und Stadium einer Pilzinfektion an. Insektenantennen, die für ihre hohe Sensitivität und Selektivität in der Duftwahrnehmung bekannt sind, stellen eine alternative Methode zur Holzprüfung dar. Ein Biosensor auf der Basis intakter Insektenantennen ermöglicht es, vom Holz freigesetzte VOCs mit hoher Selektivität nachzuweisen. Diese Methode kann eine Ergänzung zu den traditionellen Prüfverfahren darstellen und bietet einen hohen Probendurchsatz sowie ein zerstörungsfreies Verfahren. Als Beginn dieser Arbeit wurden die VOCs verschiedener Proben mit Gaschromatographie-Massenspektroskopie untersucht. Zuerst wurden die VOCs von Buchenholz (Fagus sylvatica) analysiert, das mit drei holzzersetzenden Pilzen (Trametes versicolor, Poria placenta und Gloeophyllum trabeum) infiziert war. Diese Pilze werden häufig verwendet, um die Beständigkeit von Holz gegen Mikroorganismen zu testen. Die vom pilzinfizierten Buchenholz freigesetzten VOCs zeigten artspezifische Muster. Die Volatile lassen sich gruppieren in Stoffe mit fünf bis acht Kohlenstoffen (C5-C8) sowie Terpenoide. 1-Octen-3-ol, 3-Octanon und 3-Octanol (C8-Verbindungen) waren allgemein in allen Proben enthalten, während Terpenoide artspezifisch auftraten. α- und β-Barbaten waren charakteristisch für eine Infektion mit T. versicolor, Protuillud-6-en war charakteristisch für G. trabeum und Daucen war charakteristisch für P. placenta. Als Zweites wurden VOCs identifiziert, die von verschiedenen Stadien von Trametes gibbosa mit schwacher bis vollständiger Kolonisierung durch den Käfer Cis boleti freigesetzt wurden. Die schwach besiedelten Fruchtkörper setzten den typischen Pilzduftstoff 1-Octen-3-ol in fast zwanzigfach höherer Menge frei als vollständig besiedelte Fruchtkörper. Als Drittes wurden die VOCs untersucht, die während der Fruchtkörperentwicklung vom Stadium des Myceliums bis zur Autolyse von Coprinopsis cinerea freigesetzt werden. Die VOC-Muster von C. cinerea änderten sich spezifisch mit den Entwicklungsstadien. 1-Octen-3-ol und 3-Octanon zeigten während der Bildung der Primodia eine starke Freisetzung, die in späteren Stadien abnahm. Die Terpenoide β-Himachalen und Cuparen wurden während Wachstum und Reifung des Stängels von C. cinerea drastisch erhöht. Zum Abschluss wurden die autolytischen Fruchtkörper der Tintlinge Coprinus comatus, Coprinopsis atramentaria und C. cinerea untersucht. Als zusätzliche Stoffe wurden hier stickstoff- und schwefelhaltige Verbindungen freigesetzt. Der fungivore Käfer Cis boleti (Coloptera: Ciidae) und die pilzassoziierte Fliege Suillia mikii (Diptera: Heleomizydae) wurden ausgewählt, um ihre geruchliche Wahrnehmung zu untersuchen, da ihre Lebenszyklen einen starken Bezug zu Pilzen haben. Zum Beispiel kolonisiert C. boleti vorzugsweise Pilze der Gattung Trametes und S. mikii landen gezielt auf Tintlingen in spezifischen Entwicklungsstadien. Gaschromatographie-Massenspektrometrie mit paralleler elektroantennographischer Detektion (EAD) wurde eingesetzt, um zu demonstrieren, dass beide Insektenarten in der Lage sind, den typischen Pilzgeruchsstoff 1-Octen-3-ol mit hoher Selektivität und Sensitivität nachzuweisen. Zusätzlich zeigten Verhaltenstests, dass C. boleti in der Lage ist, die Enantiomere von 1-Octen-3-ol zu unterscheiden, wobei weibliche Käfer signifikant stärker vom (S)-(+)-Enantiomer angelockt wurden und dies schon bei geringeren Konzentrationen als die männlichen Käfer. Die Fliege S. mikii reagierte in EAD-Tests reproduzierbar auf die VOCs 1-Undecene, 2-Butanon und Dimethyl-Trisulfid, die bei der Autolyse der Fruchtkörper von Tintlingen freigesetzt werden. Die Antennen von C. boleti detektierten den typischen Pilzgeruch 1-Octen-3-ol mit hoher Selektivität und Sensitivität bis zu einer Konzentration von 5 ng ml-1 in Luft. Die Lebensdauer der Antennen betrug bis zu ein Tag. Als grundlegender Test wurden Antennen von C. boleti als Biokomponenten eines Biosensorsystems benutzt, um Buchenholzproben mit Infektion durch T. versicolor zu untersuchen. Dazu diente ein Biosensorsystem, das auf der Überlagerungsmethode in Verbindung mit einem Rekalibrierungssystem basiert. In dieser Konfiguration lieferten die Antennen von C. boleti reproduzierbare Reaktionen auf die pilzlichen Markerstoffe, die von pilzinfiziertem Buchenholz freigesetzt werden. Zusammengefasst führen diese Ergebnisse zu einer aussichtsreichen Möglichkeit, einen Biosensor auf Basis von intakten Antennen als hoch empfindliche und selektive Testmethode für die Holzbeständigkeit gegen zersetzende Pilze zu entwickeln.Wood inspection and durability testing of wood against microorganisms, as fungi, play an important role in forestry and wood-related material industries. An efficient testing method is required in order to facilitate inspections and to provide the accurate and precise assessment process. Monitoring volatile organic compounds (VOCs) released from wood substrates and from fungal metabolisms are marker compounds of the wood condition, i.e., indicating the type and stage of fungal infection. Insect antennae, which are recognised for their high sensitivity and selectivity in odour perception, are an alternative method for wood testing. On the basis of intact insect antenna biosensor it is possible to monitor wood released VOCs with high selectivity. This technique can be a complement to the traditional wood testing methods, providing a high throughput and non-destructive method. This work was begun with the investigation of VOCs released from four different types of samples with gas chromatography-mass spectrometry. Firstly, VOCs from beech wood (Fagus sylvatica) infected with three wood rotting fungi; Trametes versicolor, Poria placenta, and Gloeophyllum trabeum were analysed. These fungi are commonly used in the durability testing of wood against microorganisms. The VOCs released from the fungal-infected beech showed species specific volatile patterns. The volatiles were grouped to five- and to eight- carbon (C5-C8) containing compounds and terpenoids. 1-Octen-3-ol, 3-octanone, and 3-octanol (C8-compounds) were commonly present in all samples, while terpenoids were species specific. α- and β-Barbatene were characteristic of T. versicolor-infected beech, protuillud-6-ene was characteristic of G. trabeum-infected beech, and daucene was characteristic of P. placenta-infected beech. Secondly, VOCs released from the minimally insect-colonised fruiting body (<10%) and fully insect-colonised fruiting body (~100%) of Trametes gibbosa were identified. The minimally insect-colonised fruiting body released 1-octen-3-ol, the typical fungal odour, at almost 20 times higher than in fully insect-colonised fruiting body. Thirdly, VOCs released during the fruiting body development of the ink-cap Coprinopsis cinerea, from the stage of mycelium to fruiting body autolysis, were studied. VOCs patterns of C. cinerea were specifically altered by the developmental stages. 1-Octen-3-ol and 3-octanone were largely released during primodia formation and were gradually reduced in amount in later developmental stages. The terpenoids β-himachalene and cuparene drastically increased when the C. cinerea stipe elongated and became mature. Finally, the volatiles released during fruiting bodies autolysis of C. cinerea and other two ink-cap decomposing fungi (Coprinus comatus, Coprinopsis atramentaria), were investigated. In all three cases, N-containing and S-containing compounds were additionally released during the autolytic stage. The fungivorous beetle Cis boleti (Coloptera: Ciidae) and the fungal associated fly Suillia mikii (Diptera: Heleomizydae) were chosen for examining their olfactory perception since their life cycles are strongly related to fungi. For instance, C. boleti preferentially colonises fungi from the genus Trametes and S. mikii purposely land on the ink-cap fungi at a specific developmental stage. Gas chromatography-mass spectrometry with parallel electroantennographic detection was employed to demonstrate that both insect species are able to perceive the typical fungal odour 1-octen-3-ol with high selectivity and sensitivity. In addition, behavioural tests of C. boleti showed that this insect is able to discriminate the enantiomers of 1-octen-3-ol, where the female beetles were significantly more attracted to the (S)-(+) enantiomer at lower doses than male beetles. The fly S. mikii reproducibly responded to the VOCs 1-undecene, 2-butanone, and dimethyl trisulfide, released from the autolysis fruiting bodies of the ink-cap fungi. The C. boleti antenna perceived the typical fungal odour, 1-octen-3-ol, with high selectivity and sensitivity of down to 5 ng ml-1 in air. The antenna life time lasted up to one day. Consequently, as a proof of principle C. boleti antenna was used as a biocomponent in a biosensor system for testing beech wood samples infected by T. versicolor. The biosensor system using the superposition method in combination with a recalibration system was adopted. In this configuration C. boleti antenna yielded reproducible responses to the fungal marker volatile compound released from fungal-infected beech wood. Altogether these results lead to a promising possibility to set up a biosensor based on intact antenna as a highly sensitive and selective testing method for wood durability against decay fungi
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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