Chemical Composition of Fresh Leaves Headspace Aroma and Essential Oils of Four Coriander Cultivars.

Aroma is one of the key food characteristics determining consumers' perception and acceptability of products. L. is an aromatic herb commonly used as a food additive and taste enhancer.

Variation in Methyl Jasmonate-Induced Defense Among Norway Spruce Clones and Trade-Offs in Resistance Against a Fungal and an Insect Pest.

An essential component of plant defense is the change that occurs from a constitutive to an induced state following damage or infection. Exogenous application of the plant hormone methyl jasmonate (MeJA) has shown great potential to be used as a defense inducer prior to pest exposure, and could be used as a plant protection measure. Here, we examined (1) the importance of MeJA-mediated induction for Norway spruce () resistance against damage by the pine weevil , which poses a threat to seedling survival, and infection by the spruce bark beetle-associated blue-stain fungus , (2) genotypic variation in MeJA-induced defense (terpene chemistry), and (3) correlations among resistance to each pest.

Acaricidal activity against Ixodes ricinus nymphs of essential oils from the Libyan plants Artemisia herba alba, Origanum majorana and Juniperus phoenicea.

Ixodes ricinus (L.) (Acari: Ixodidae) is a major vector for the transmission of several important human pathogens. The aim of the present study was to evaluate the in vitro efficacy of different concentrations of essential oils (Eos) on I.

Composition of Strawberry Floral Volatiles and their Effects on Behavior of Strawberry Blossom Weevil, Anthonomus rubi.

The strawberry blossom weevil (SBW), Anthonomus rubi, is a major pest in strawberry fields throughout Europe. Traps baited with aggregation pheromone are used for pest monitoring. However, a more effective lure is needed.

Male swarming aggregation pheromones increase female attraction and mating success among multiple African malaria vector mosquito species.

Accumulating behavioural data indicate that aggregation pheromones may mediate the formation and maintenance of mosquito swarms. However, chemical cues possibly luring mosquitoes to swarms have not been adequately investigated, and the likely molecular incitants of these complex reproductive behaviours remain unknown. Here we show that males of the important malaria vector species Anopheles arabiensis and An.

Resin acids as inducible chemical defences of pine seedlings against chewing insects.

Inducibility of defences in response to biotic stimuli is considered an important trait in plant resistance. In conifers, previous research has mostly focused on the inducibility of the volatile fraction of the oleoresin (mono- and sesquiterpenes), leaving the inducibility of the non-volatile resin acids largely unexplored, particularly in response to real herbivory. Here we investigated the differences in the inducibility of resin acids in two pine species, one native from Europe (Pinus pinaster Ait.

Identification of ()-8-Heptadecene and -Pentadecane as Electrophysiologically Active Compounds in and Its Pollinator.

Sexually deceptive orchids typically depend on specific insect species for pollination, which are lured by sex pheromone mimicry. European orchids often exploit specific species of wasps or bees with carboxylic acid derivatives. Here, we identify the specific semiochemicals present in , and in females of one of its pollinator species, .

Priming of inducible defenses protects Norway spruce against tree-killing bark beetles.

Plants can form an immunological memory known as defense priming, whereby exposure to a priming stimulus enables quicker or stronger response to subsequent attack by pests and pathogens. Such priming of inducible defenses provides increased protection and reduces allocation costs of defense. Defense priming has been widely studied for short-lived model plants such as Arabidopsis, but little is known about this phenomenon in long-lived plants like spruce.

Anti-aphrodisiac pheromone, a renewable signal in adult butterflies.

The male butterfly Pieris napi produces the anti-aphrodisiac pheromone methyl salicylate (MeS) and transfers it to the female during mating. After mating she releases MeS, when courted by conspecific males, which decreases her attractiveness and the duration of male harassment, thus increasing her time available for egg-laying. In previous studies we have shown that males produced MeS from the amino acid L-phenylalanine (L-Phe) acquired during larval stage.

Heterobasidion-growth inhibiting Bacillus subtilis A18 exhibits medium- and age-dependent production of lipopeptides.

Heterobasidion annosum s.s. and H.

The repellency and toxicity effects of essential oils from the Libyan plants Salvadora persica and Rosmarinus officinalis against nymphs of Ixodes ricinus.

Essential oils extracted from the leaves of Libyan Rosemary (Rosmarinus officinalis L.), and Miswak (Salvadora persica L.) were evaluated for their acaricidal and repellent effects on Ixodes ricinus L.

Convergent evolution of semiochemicals across Kingdoms: bark beetles and their fungal symbionts.

Convergent evolution of semiochemical use in organisms from different Kingdoms is a rarely described phenomenon. Tree-killing bark beetles vector numerous symbiotic blue-stain fungi that help the beetles colonize healthy trees. Here we show for the first time that some of these fungi are able to biosynthesize bicyclic ketals that are pheromones and other semiochemicals of bark beetles.

Inducibility of Plant Secondary Metabolites in the Stem Predicts Genetic Variation in Resistance Against a Key Insect Herbivore in Maritime Pine.

Resistance to herbivores and pathogens is considered a key plant trait with strong adaptive value in trees, usually involving high concentrations of a diverse array of plant secondary metabolites (PSM). Intraspecific genetic variation and plasticity of PSM are widely known. However, their ecology and evolution are unclear, and even the implication of PSM as traits that provide direct effective resistance against herbivores is currently questioned.

Diterpenoid fingerprints in pine foliage across an environmental and chemotypic matrix: Isoabienol content is a key trait differentiating chemotypes.

Diterpenoids constitute an important part of oleoresin in conifer needles, but the environmental and genetic controls on diterpenoid composition are poorly known. We studied the presence of diterpenoids in four pine populations spanning an extensive range of nitrogen (N) availability. In most samples, isoabienol was the main diterpenoid.

Essential oils of aromatic Egyptian plants repel nymphs of the tick Ixodes ricinus (Acari: Ixodidae).

Due to the role of Ixodes ricinus (L.) (Acari: Ixodidae) in the transmission of many serious pathogens, personal protection against bites of this tick is essential. In the present study the essential oils from 11 aromatic Egyptian plants were isolated and their repellent activity against I.

Sulfate turpentine: a resource of tick repellent compounds.

Compounds with tick (Ixodes ricinus) repellent properties were isolated from sulfate turpentine consisting of Norway spruce (80%) and Scots pine (20%) from southern Sweden. The turpentine was divided into two fractions by distillation under reduced pressure resulting in one monoterpene hydrocarbon fraction and a residual containing higher boiling terpenoids. The monoterpene fraction was further oxidized with SeO to obtain oxygenated monoterpenes with potential tick repellent properties.

Investigations of a Possible Chemical Effect of Chewing Sticks.

is commonly used chewing sticks in many parts of the world as an oral hygiene tool. This study measured the amount of benzyl isothiocyanate (BITC) released into the mouth and assessed its retention time in saliva. The study also tested if the released amount of BITC could potentially be antibacterial or cytotoxic.

A key malaria metabolite modulates vector blood seeking, feeding, and susceptibility to infection.

Malaria infection renders humans more attractive to sensu lato mosquitoes than uninfected people. The mechanisms remain unknown. We found that an isoprenoid precursor produced by , ()-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMBPP), affects s.

Antifeedants Produced by Bacteria Associated with the Gut of the Pine Weevil Hylobius abietis.

The pine weevil, Hylobius abietis, is a severe forest pest insect as it feeds on newly planted conifer seedlings. To identify and develop an antifeedant could be one step towards the protection of seedlings from feeding damage by the pine weevil. With the aim to trace the origin of the antifeedants previously found in feces of the pine weevil, we investigated the culturable bacteria associated with the gut and identified the volatiles they produced.

Methyl Jasmonate-Induced Monoterpenes in Scots Pine and Norway Spruce Tissues Affect Pine Weevil Orientation.

In large parts of Europe, insecticide-free measures for protecting conifer plants are desired to suppress damage by the pine weevil Hylobius abietis (L.). Treatment with methyl jasmonate (MeJA), a chemical elicitor already used in crop production, may enhance expression of chemical defenses in seedlings in conifer regenerations.

Essential Oils from Ugandan Medicinal Plants: Cytotoxicity and Effects on IL-1-Induced Proinflammatory Mediators by Human Gingival Fibroblasts.

The study investigated cytotoxicity of essential oils from four medicinal plants (, , , and ) on human gingival fibroblasts and their effects on proinflammatory mediators' secretion. Cytotoxicity of essential oils was investigated using 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay. Effects of essential oils at subcytotoxicity concentrations on interleukin- (IL-) 6, IL-8, and prostaglandin E (PGE) secretions by gingival fibroblasts treated with IL-1 (300 pg/mL) were evaluated by ELISA and EIA.

Cedrol, a malaria mosquito oviposition attractant is produced by fungi isolated from rhizomes of the grass Cyperus rotundus.

Background: Cedrol, a sesquiterpene alcohol, is the first identified oviposition attractant for African malaria vectors. Finding the natural source of this compound might help to elucidate why Anopheles gambiae and Anopheles arabiensis prefer to lay eggs in habitats containing it. Previous studies suggest that cedrol may be a fungal metabolite and the essential oil of grass rhizomes have been described to contain a high amount of different sesquiterpenes.

Induced defenses change the chemical composition of pine seedlings and influence meal properties of the pine weevil Hylobius abietis.

The defense of conifers against phytophagous insects relies to a large extent on induced chemical defenses. However, it is not clear how induced changes in chemical composition influence the meal properties of phytophagous insects (and thus damage rates). The defense can be induced experimentally with methyl jasmonate (MeJA), which is a substance that is produced naturally when a plant is attacked.

The gut microbiota of the pine weevil is similar across Europe and resembles that of other conifer-feeding beetles.

The pine weevil (Hylobius abietis, Coleoptera: Curculionidae) is an important pest of conifer seedlings in Europe. Despite its economic importance, little is known about the composition of its gut microbial community and the role it plays in mediating the weevil's ability to utilize conifers as a food source. Here, we characterized the gut bacterial communities of different populations of H.

Gravid Anopheles gambiae sensu stricto avoid ovipositing in Bermuda grass hay infusion and it's volatiles in two choice egg-count bioassays.

Background: A number of mosquito species in the Culex and Aedes genera prefer to lay eggs in Bermuda grass (Cynodon dactylon) hay infusions compared to water alone. These mosquitoes are attracted to volatile compounds from the hay infusions making the infusions effective baits in gravid traps used for monitoring vectors of arboviral and filarial pathogens. Since Bermuda grass is abundant and widespread, it is plausible to explore infusions made from it as a potential low cost bait for outdoor monitoring of the elusive malaria vector Anopheles gambiae s.