25 research outputs found
Honey Plotter and the Web of Terror
Honeypots are a useful tool for discovering the
distribution of malicious traffic on the Internet and how that
traffic evolves over time. In addition, they allow an insight into
new attacks appearing. One major problem is analysing the large
amounts of data generated by such honeypots and correlating
between multiple honeypots. Honey Plotter is a web-based query
and visualisation tool to allow investigation into data gathered by
a distributed honeypot network. It is built on top of a relational
database, which allows great flexibility in the questions that can
be asked and has automatic generation of visualisations based on
the results of queries. The main focus is on aggregate statistics but
individual attacks can also be analysed. Statistical comparison of
distributions is also provided to assist with detecting anomalies
in the data; helping separate out common malicious traffic from
new threats and trends. Two short case studies are presented to
give an example of the types of analysis that can be performed
Identification of volatile compounds involved in host location by Anthonomus grandis (Coleoptera: Curculionidae).
Na publicação: Maria C. Blassioli-Moraes
Pea aphid odorant-binding protein ApisOBP6 discriminates between aphid sex pheromone components, aphid alarm pheromone and a host plant volatile
Olfactory perception of pheromones in insects involves odorant-binding proteins (OBPs), relatively small proteins (ca.110-240 amino acid residues) that can bind reversibly to behaviourally active olfactory ligands. In this study, we investigated the binding in silico and in vitro of the aphid sex pheromone components (1R,4aS,7S,7aR)-nepetalactol and (4aS,7S,7aR)-nepetalactone and the aphid alarm pheromone (E)-β-farnesene by OBPs from the pea aphid, Acyrthosiphon pisum. Screening of protein models of ApisOBPs1-11 with the aphid sex pheromone components suggested that ApisOPB6 was a candidate. Fluorescence assays using ApisOBP6 suggested that ApisOBP6 was able to bind both sex pheromone components and discriminate from the aphid alarm pheromone and the generic plant compound (R/S)-linalool. Saturation transfer difference NMR experiments with ApisOBP6 yielded results consistent to those from the fluorescence experiments, with a clear interaction between ApisOBP6 and (4aS,7S,7aR)-nepetalactone. These results describe a novel interaction and potential function for ApisOBP6, point to pre-receptor odorant discrimination by OBPs, and provide a platform for investigating the function of other aphid olfactory proteins involved in aphid chemical ecology
A crotonyl-CoA reductase-carboxylase independent pathway for assembly of unusual alkylmalonyl-CoA polyketide synthase extender units
Type I modular polyketide synthases assemble diverse bioactive natural products. Such multienzymes typically use malonyl and methylmalonyl-CoA building blocks for polyketide chain assembly. However, in several cases more exotic alkylmalonyl-CoA extender units are also known to be incorporated. In all examples studied to date, such unusual extender units are biosynthesized via reductive carboxylation of α, β-unsaturated thioesters catalysed by crotonyl-CoA reductase/carboxylase (CCRC) homologues. Here we show using a chemically-synthesized deuterium-labelled mechanistic probe, and heterologous gene expression experiments that the unusual alkylmalonyl-CoA extender units incorporated into the stambomycin family of polyketide antibiotics are assembled by direct carboxylation of medium chain acyl-CoA thioesters. X-ray crystal structures of the unusual β-subunit of the acyl-CoA carboxylase (YCC) responsible for this reaction, alone and in complex with hexanoyl-CoA, reveal the molecular basis for substrate recognition, inspiring the development of methodology for polyketide bio-orthogonal tagging via incorporation of 6-azidohexanoic acid and 8-nonynoic acid into novel stambomycin analogues
Revisiting the male-produced aggregation pheromone of the lesser mealworm, Alphitobius diaperinus (Coleoptera, Tenebrionidae): identification of a six-component pheromone from a Brazilian population
The lesser mealworm, Alphitobius diaperinus Panzer 1797 (Coleoptera: Tenebrionidae), is a cosmopolitan insect pest affecting poultry production. Due to its cryptic behavior, insecticide control is usually not efficient. Thus, sustainable and effective methods would have an enormous and positive impact in poultry production. The aim of this study was to confirm the identity of the male-produced aggregation pheromone for a Brazilian population of A. diaperinus and to evaluate its biological activity in behavioral assays. Six male-specific compounds were identified: (R)-limonene (1), (E)-ocimene (2), 2-nonanone (3), (S)-linalool (4), (R)-daucene (5), all described before in an American population, and a sixth component, (E,E)-α-farnesene (6), which is apparently exclusive to a Brazilian population. Y-Tube bioassays confirmed the presence of a male-produced aggregation pheromone and showed that all components need to be present in a similar ratio and concentration as emitted by male A. diaperinus to produce a positive chemotactic response
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(2R,5S)-theaspirane identified as the kairomone for the banana weevil, Cosmopolites sordidus, from attractive senesced leaves of the host banana, Musa spp.
The principal active component produced by highly attractive senesced host banana leaves, Musa spp., for the banana weevil, Cosmopolites sordidus, is shown by coupled gas chromatography‐electroantennography (GC‐EAG), coupled GC‐mass spectrometry (GC‐MS), chemical synthesis and coupled enantioselective (chiral) GC‐EAG to be (2R,5S)‐theaspirane. In laboratory behaviour tests, the synthetic compound is as attractive as natural host leaf material and presents a new opportunity for pest control
A lucernapoloska, Adelphocoris lineolatus lehetséges szexferomon-antagonistája (Hemiptera: Miridae)
Development of pull and push–pull systems for management of lesser mealworm, Alphitobius diaperinus, in poultry houses using alarm and aggregation pheromones
BACKGROUND: The lesser mealworm, Alphitobius diaperinus (Coleoptera: Tenebrionidae), is the most important
insect pest affecting poultry production around the world, with all life stages being susceptible to infection by
bacteria, viruses and fungi. Control of A. diaperinus in poultry houses using intensive insecticide application is not
effective due to the cryp-tic behaviour of this pest. Here, we evaluated the potential of recently identified A.
diaperinus alarm (1,4-benzoquinone, 2-methyl-1,4-benzoquinone and 2-ethyl-1,4-benzoquinone) and aggregation [(R)-
limonene, 2-nonanone, (E)-ocimene, (S)-linalool, (R)-daucene and (E,E)- -farnesene] pheromones as tools for the
management of this pest in poultry houses in Brazil.
RESULTS: Laboratory arena assays with synthetic alarm pheromone confirmed A. diaperinus repellency. In an initial field assay,
traps baited with synthetic aggregation pheromone captured significantly more insects than control traps. In further field assays
that compared a pull (aggregation pheromone) and a push–pull (simultaneous alarm/aggregation pheromone deployment) system,
a higher number of A. diaperinus were captured in aggregation pheromone-baited traps in the push–pull system.
CONCLUSION: Our results suggest that alarm and aggregation pheromones can be deployed in poultry houses to trap significant
numbers of adult A. diaperinus. Studies are underway to determine the potential for using these components as part of an
integrated A. diaperinus management strategy
Iridoid Sex Pheromone Biosynthesis in Aphids Mimics Iridoid?Producing Plants
Biosynthesis of (1R,4aS,7S,7aR)?nepetalactol (1) and (4aS,7S,7aR)?nepetalactone (2) in plants involves iridoid synthase (ISY), an atypical reductive cyclase that catalyses the reduction of 8?oxogeranial into the reactive enol of (S)?8?oxocitronellal, and cyclization of this enol intermediate, either non?enzymatically or by a nepetalactol?related short chain dehydrogenase enzyme (NEPS) that yields the nepetalactols. In this study, we investigated the biosynthesis in?vivo of 1 and 2 in the pea aphid, Acyrthosiphon pisum, using a library of isotopically?labelled monoterpenoids as molecular probes. Topical application of deuterium?labelled probes synthesized from geraniol and nerol resulted in production of 2H4?lactol 1 and 2H4?lactone 2. However, deuterium incorporation was not evident using labelled probes synthesized from (S)?citronellol. These results suggest that iridoid biosynthesis in animals, specifically aphids, may follow a broadly similar route to that characterised for plants
Challenges in the capture and dissemination of measurements from high-speed networks
The production of a large-scale monitoring system for a high-speed network leads to a number of challenges. These challenges are not purely technical but also socio-political and legal. The number of stakeholders in such monitoring activity is large including the network operators, the users, the equipment manufacturers and, of course, the monitoring researchers. The MASTS project (measurement at all scales in time and space) was created to instrument the high-speed JANET Lightpath network and has been extended to incorporate other paths supported by JANET(UK). Challenges the project has faced included: simple access to the network; legal issues involved in the storage and dissemination of the captured information, which may be personal; the volume of data captured and the rate at which these data appear at store. To this end, the MASTS system will have established four monitoring points each capturing packets on a high-speed link. Traffic header data will be continuously collected, anonymised, indexed, stored and made available to the research community. A legal framework for the capture and storage of network measurement data has been developed which allows the anonymised IP traces to be used for research purposes