The BG-Sentinel, a novel mosquito trap for research and surveillance

Um Informationen zur Verbreitung und Populationsdichte von Stechmücken zu gewinnen, werden verschiedene Methoden verwendet. Neben der Suche nach Larven oder Puppen in den Brutgewässern, dem Absuchen von Ruheplätzen nach Adulten und den Fang aktiver, wirtssuchender Mückenweibchen durch freiwillige Mückenfänger werden vor allem unterschiedliche Fallentypen verwendet. Abgesehen von zwar preiswerten, aber wenig effizienten Fallen für gravide (also nicht mehr wirtsuchende) Mückenweibchen werden bisher Fallen mit unspezifische Lockreizen betrieben (Farbkontraste, Licht, Kohlendioxid). Letzteres ist in seiner Verwendung zudem aufwendig und teuer, da es aus Trockeneis, aus Gasflaschen oder der Verbrennung von Propangas freigesetzt werden muß. Wir stellen einen neuartigen Fallentypus für Stechmücken vor, den BG-Sentinel (Abb. 1). Die Falle wurde ursprünglich für die Überwachung der Gelbfiebermücke Stegomyia aegypti (ehemals Aedes aegypti, REINERT et al. 2004) entwickelt, ist aber auch für eine Reihe anderer Mücken attraktiv. Der BG-Sentinel ist die erste Falle, die neben visuellen Reizen auch, wie ein natürlicher Wirt, eine aufwärtsgerichtete Luftströmung produziert. Diese Luftströmung kann durch Zugabe geeigneter Düfte mit Lockstoffen beladen werden. Wir stellen außerdem mit der sogenannten BG-Lure einen neuen Mückenlockstoff vor, der aus Substanzen besteht, die auch auf der menschlichen Haut vorkommt. Die Konstruktion des BG-Sentinel ermöglicht es, eine Vielzahl verschiedener Reize auf ihre Attraktivität im Feld zu testen. Im Folgenden werden Feldtests des BG-Sentinel mit Stegomyia aegypti in Brasilien und Culex pipiens in Deutschland beschrieben.We introduce a novel, patent pending type of mosquito trap, the BG-Sentinel®. The trap consists of an easy to transport, collapsible white bucket with white gauze covering its opening. In the middle of the gauze cover, there is a black tube through which a down flow is created by a fan that draws approaching mosquitoes into a catch bag. The air then exits the trap through the gauze; the design therefore generates ascending currents. These are similar to convection currents produced by a human host, both in its direction, its geometrical structure, and, due to the addition of attractants, also in its chemical composition. The attractants are given off by the so-called BG-Lure®, a dispenser which releases a defined, patent pending combination of lactic acid, ammonia, and caproic acid, all substances that are found on human skin. The dispenser emits the attractants for up to 5 month. The addition of CO2 is not necessary for species such as Stegomyia aegypti (syn. Aedes aegypti) or St. albopicta (syn Ae. albopictus). In field tests in Belo Horizonte, Brazil, the BGSentinel with the BG-Lure was much more efficient in catching the yellow fever mosquito St. aegypti than a propane-powered CO2-trap and a bidirectional Fay-Prince trap. The tests also indicate that the BG-Sentinel can be a sensitive and easy-to-use alternative to human landing/biting collections in the surveillance of adult host seeking Dengue vectors. Further field tests near Regensburg in Germany showed that the BG-Sentinel with the BG-Lure is also an efficient trap for Culex pipiens. The addition of CO2 or 2-Undecanone did not further improve the attractiveness of the BG-Lure. Due to its design, the BG-Sentinel can be used with a variety of other potential mosquito attractants, making it a versatile tool for mosquito research and surveillance

Laboratory And Field Assessment Of Some Kairomone Blends For Host-Seeking \u3ci\u3eAedes Aegypti\u3c/i\u3e

Using laboratory Y-tube olfactometers, the attractiveness of lactic acid and 2 kairomone blends from the United States Department of Agriculture (USDA) and BioGents GmbH (BG) was assessed for attractiveness to Aedes aegypti. Four geographically disparate populations were assessed: North Queensland Australia (NQA), Florida USA, Minas Gerais Brazil (MGB), and Singapore. In descending order, populations were attracted to USE)A, BG blends, and lactic acid. MGB was poorly attracted to lactic acid alone. The blends were less attractive than human odor. Proprietary blends were modified, and their attractiveness was assessed to find the optimum attractive mixture for NQA. Adding acetone to BG, and ammonia and caproic acid to USDA, improved attractiveness in the laboratory. Field attractiveness was assessed by coupling the blends with a newly developed BG-Sentinel Ae. aegypti trap. Trials were carried out using the BG blend, BG blend plus acetone, USDA blend, USDA blend plus ammonia and caproic acid, and a control trap with no kairomones. The traps were highly effective, with mean 24-h collections up to 11.15 Ae. aegypti per trap, and this species made up 91.7% of collections. However, the effectiveness of the unbaited control trap indicated that the BG-Sentinel has visual attractive properties for Ae. aegypti and that the kairomone lures added little to trap performance in NQA

Epstein-Barr virus transcription factor Zta acts through distal regulatory elements to directly control cellular gene expression

Lytic replication of the human gamma herpes virus Epstein-Barr virus (EBV) is an essential prerequisite for the spread of the virus. Differential regulation of a limited number of cellular genes has been reported in B-cells during the viral lytic replication cycle. We asked whether a viral bZIP transcription factor, Zta (BZLF1, ZEBRA, EB1), drives some of these changes. Using genome-wide chromatin immunoprecipitation coupled to next-generation DNA sequencing (ChIP-seq) we established a map of Zta interactions across the human genome. Using sensitive transcriptome analyses we identified 2263 cellular genes whose expression is significantly changed during the EBV lytic replication cycle. Zta binds 278 of the regulated genes and the distribution of binding sites shows that Zta binds mostly to sites that are distal to transcription start sites. This differs from the prevailing view that Zta activates viral genes by binding exclusively at promoter elements. We show that a synthetic Zta binding element confers Zta regulation at a distance and that distal Zta binding sites from cellular genes can confer Zta-mediated regulation on a heterologous promoter. This leads us to propose that Zta directly reprograms the expression of cellular genes through distal elements

Wafer-scale selective area growth of GaN hexagonal prismatic nanostructures on c-sapphire substrate

Selective area growth of GaN nanostructures has been performed on full 2" c-sapphire substrates using Si3N4 mask patterned by nanoimprint lithography (array of 400 nm diameter circular holes). A new process has been developed to improve the homogeneity of the nucleation selectivity of c-oriented hexagonal prismatic nanostructures at high temperature (1040\circ C). It consists of an initial GaN nucleation step at 950 \circ C followed by ammonia annealing before high temperature growth. Structural analyses show that GaN nanostructures are grown in epitaxy with c-sapphire with lateral overgrowths on the mask. Strain and dislocations are observed at the interface due to the large GaN/sapphire lattice mismatch in contrast with the high quality of the relaxed crystals in the lateral overgrowth area. A cathodoluminescence study as a function of the GaN nanostructure size confirms these observations: the lateral overgrowth of GaN nanostructures has a low defect density and exhibits a stronger near band edge (NBE) emission than the crystal in direct epitaxy with sapphire. The shift of the NBE positions versus nanostructure size can be mainly attributed to a combination of compressive strain and silicon doping coming from surface mask diffusion

CpG-Methylation Regulates a Class of Epstein-Barr Virus Promoters

DNA methylation is the major modification of eukaryotic genomes and plays an essential role in mammalian gene regulation. In general, cytosine-phosphatidyl-guanosine (CpG)-methylated promoters are transcriptionally repressed and nuclear proteins such as MECP2, MBD1, MBD2, and MBD4 bind CpG-methylated DNA and contribute to epigenetic silencing. Methylation of viral DNA also regulates gene expression of Epstein-Barr virus (EBV), which is a model of herpes virus latency. In latently infected human B cells, the viral DNA is CpG-methylated, the majority of viral genes is repressed and virus synthesis is therefore abrogated. EBV's BZLF1 encodes a transcription factor of the AP-1 family (Zta) and is the master gene to overcome viral gene repression. In a genome-wide screen, we now identify and characterize those viral genes, which Zta regulates. Among them are genes essential for EBV's lytic phase, which paradoxically depend on strictly CpG-methylated promoters for their Zta-induced expression. We identified novel DNA recognition motifs, termed meZRE (methyl-Zta-responsive element), which Zta selectively binds in order to ‘read’ DNA in a methylation- and sequence-dependent manner unlike any other known protein. Zta is a homodimer but its binding characteristics to meZREs suggest a sequential, non-palindromic and bipartite DNA recognition element, which confers superior DNA binding compared to CpG-free ZREs. Our findings indicate that Zta has evolved to transactivate cytosine-methylated, hence repressed, silent promoters as a rule to overcome epigenetic silencing

Optical gas sensing device.

An optical gas sensing device (10) is specified comprising a gas detecting unit (1) wherein the gas detecting unit (1) comprises an array of semiconductor based nanostructures (1a), the nanostructures (1a) each having a surface which is capable of photo-induced adsorption of gas molecules (3) leading to a non-radiative surface-related recombination