A diterpene synthase from the sandfly produces the pheromone sobralene.

The phlebotomine sandfly, , a major vector of the parasite, uses terpene pheromones to attract conspecifics for mating. Examination of the genome revealed a putative terpene synthase (TPS), which-upon heterologous expression in, and purification from, -yielded a functional enzyme. The TPS, termed TPS, converted geranyl diphosphate (GPP) into a mixture of monoterpenes with low efficiency, of which β-ocimene was the major product.

Evaluating repellence properties of catnip essential oil against the mosquito species Aedes aegypti using a Y-tube olfactometer.

The mosquito species Aedes aegypti (L.) is known to act as a vector in the transmission of various diseases, including dengue fever and yellow fever. The use of insect repellents is one of precautionary measures used to mitigate the risk of these diseases in humans by reducing mosquito biting.

Unprecedented oviposition tactics avoid plant defences and reduce attack by parasitic wasps.

Female insects oviposit in sites suitable for the development of their offspring. The Oriental armyworm, Mythimna separata is a serious pest of various crops including wheat and prefers to oviposit on withered leaves rather than on fresh plant material, which is surprisingly different from other insects. Studies here showed that this oviposition tactic enables avoidance of wheat defence against eggs and emerged larvae.

Characterisation of geranylgeranyl diphosphate synthase from the sandfly Lutzomyia longipalpis.

Leishmaniasis is a debilitating and often fatal neglected tropical disease. Males from sub-populations of the Leishmania-harbouring sandfly, Lutzomyia longipalpis, produce the diterpene sex and aggregation pheromone, sobralene, for which geranylgeranyl diphosphate (GGPP) is the likely isoprenoid precursor. We have identified a GGPP synthase (lzGGPPS) from L.

Small volatile lipophilic molecules induced belowground by aphid attack elicit a defensive response in neighbouring un-infested plants.

In pioneering studies on plant-aphid interactions, we have observed that plants infested by aphids can transmit signals via the rhizosphere that induce aboveground defence in intact, neighbouring plants. The aphid parasitoid is significantly attracted towards intact broad bean plants grown in a hydroponic solution previously harbouring -infested plants. To identify the rhizosphere signal(s) possibly mediating this belowground plant-plant communication, root exudates were collected using Solid-Phase Extraction (SPE) from 10-day old -infested and un-infested plants hydroponically grown.

A Horizon Scan to Support Chemical Pollution-Related Policymaking for Sustainable and Climate-Resilient Economies.

While chemicals are vital to modern society through materials, agriculture, textiles, new technology, medicines, and consumer goods, their use is not without risks. Unfortunately, our resources seem inadequate to address the breadth of chemical challenges to the environment and human health. Therefore, it is important we use our intelligence and knowledge wisely to prepare for what lies ahead.

L-DOPA functions as a plant pheromone for belowground anti-herbivory communication.

While mechanisms of plant-plant communication for alerting neighbouring plants of an imminent insect herbivore attack have been described aboveground via the production of volatile organic compounds (VOCs), we are yet to decipher the specific components of plant-plant signalling belowground. Using bioassay-guided fractionation, we isolated and identified the non-protein amino acid l-DOPA, released from roots of Acyrtosiphon pisum aphid-infested Vicia faba plants, as an active compound in triggering the production of VOCs released aboveground in uninfested plants. In behavioural assays, we show that after contact with l-DOPA, healthy plants become highly attractive to the aphid parasitoid (Aphidius ervi), as if they were infested by aphids.

(-)-Adaline from the Genus of Ladybirds Is a Potent Antagonist of Insect and Specific Mammalian Nicotinic Acetylcholine Receptors.

Ladybird beetles (Coleoptera: Coccinellidae) possess strong chemical defences that are secreted in response to stress and are also found on the coating of eggs, which are rich in alkaloids that are responsible for their toxicity to other species. Recent studies have shown that alkaloids from several species of ladybird beetle can target nicotinic acetylcholine receptors (nAChRs) acting as receptor antagonists. Here, we have explored the actions of (-)-adaline, found in the 2-spot () and 10-spot () ladybirds, on both mammalian (α1β1γδ, α7, α4β2, α3β4) and insect nAChRs using patch-clamp of TE671 cells and locust brain neurons natively expressing nAChRs, as well as two-electrode voltage clamp of oocytes recombinantly expressing nAChRs.

Genetic Manipulation of Biosynthetic Pathways in Mint.

In recent years, the study of aromatic plants has seen an increase, with great interest from industrial, academic, and pharmaceutical industries. Among plants attracting increased attention are the spp. (mint), members of the Lamiaceae family.

Using trained dogs and organic semi-conducting sensors to identify asymptomatic and mild SARS-CoV-2 infections: an observational study.

Background: A rapid, accurate, non-invasive diagnostic screen is needed to identify people with SARS-CoV-2 infection. We investigated whether organic semi-conducting (OSC) sensors and trained dogs could distinguish between people infected with asymptomatic or mild symptoms, and uninfected individuals, and the impact of screening at ports-of-entry.

Methods: Odour samples were collected from adults, and SARS-CoV-2 infection status confirmed using RT-PCR.

Bumblebee electric charge stimulates floral volatile emissions in Petunia integrifolia but not in Antirrhinum majus.

The timing of volatile organic compound (VOC) emission by flowering plants often coincides with pollinator foraging activity. Volatile emission is often considered to be paced by environmental variables, such as light intensity, and/or by circadian rhythmicity. The question arises as to what extent pollinators themselves provide information about their presence, in keeping with their long co-evolution with flowering plants.

Chemical Identity and Functional Characterization of Semiochemicals That Promote the Interactions between Rice Plant and Rice Major Pest .

The interaction between food crops and insect pests is mediated by semiochemicals emitted from host plants. These semiochemicals are natural behavioral modifiers and act on the insect olfactory system to locate hosts and preys. In this study, eight rice neuroactive semiochemicals were identified from rice varieties by GC-EAG and GC-MS.

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 H -lactol 1 and H -lactone 2.

Effects of Nicotine and Tobacco-Related Products on the Feeding Behavior of the German Cockroach (Blattodea: Blattellidae).

Animals use olfaction to detect developmentally significant volatile organic compounds (VOCs) in their local environment. As part of a wider study aiming to demonstrate that the olfactory responses of animals to VOCs can be modified through the creation of a drug-addicted status and association with a selected VOC, we investigated nicotine and tobacco smoke particulate (TSP) extract as possible addictive compounds for male German cockroaches, Blattella germanica (Linnaeus). In feeding experiments using an artificial food stimulus, food treated with TSP extract was preferred over untreated food.

Three Aphid-Transmitted Viruses Encourage Vector Migration From Infected Common Bean () Plants Through a Combination of Volatile and Surface Cues.

Bean common mosaic virus (BCMV), bean common mosaic necrosis virus (BCMNV), and cucumber mosaic virus (CMV) are important pathogens of common bean (), a crop vital for food security in sub-Saharan Africa. These viruses are vectored by aphids non-persistently, with virions bound loosely to stylet receptors. These viruses also manipulate aphid-mediated transmission by altering host properties.

Transcriptional profile of genes involved in the production of terpenes and glyceollins in response to biotic stresses in soybean.

Terpenes produced by plants comprise a diverse range of secondary metabolites, including volatile organic compounds (VOCs). Terpene VOC production may be altered after damage or by biological stimuli such as bacterial, fungal and insects, and subsequent triggering of plant defense responses. These VOCs originate in plants from two independent pathways: the mevalonate and the methylerythritol phosphate pathways, which utilize dimethylallyl and isopentenyl diphosphates to form the terpenoidal precursors.

Overexpression of the homoterpene synthase gene, OsCYP92C21, increases emissions of volatiles mediating tritrophic interactions in rice.

Plant defence homoterpenes can be used to attract pest natural enemies. However, the biosynthetic pathway of homoterpenes is still unknown in rice, and the practical application of such indirect defence systems suffers from inherent limitations due to their low emissions from plants. Here, we demonstrated that the protein OsCYP92C21 is responsible for homoterpene biosynthesis in rice.

Genome wide association analysis of a stemborer egg induced "call-for-help" defence trait in maize.

Tritrophic interactions allow plants to recruit natural enemies for protection against herbivory. Here we investigated genetic variability in induced responses to stemborer egg-laying in maize Zea mays (L.) (Poaceae).

Characterizing human odorant signals: insights from insect semiochemistry and modelling.

Interactions relating to human chemical signalling, although widely acknowledged, are relatively poorly characterized chemically, except for human axillary odour. However, the extensive chemical ecology of insects, involving countless pheromone and other semiochemical identifications, may offer insights into overcoming problems of characterizing human-derived semiochemicals more widely. Current techniques for acquiring insect semiochemicals are discussed, particularly in relation to the need for samples to relate, as closely as possible, to the ecological situation in which they are naturally deployed.

Responses of the putative trachoma vector, Musca sorbens, to volatile semiochemicals from human faeces.

The putative vector of trachoma, Musca sorbens, prefers to lay its eggs on human faeces on the ground. This study sought to determine whether M. sorbens females were attracted to volatile odours from human faeces in preference to odours from the faeces of other animals, and to determine whether specific volatile semiochemicals mediate selection of the faeces.