There is widespread interkingdom signalling between insects and microbes. For example, microbes found in floral nectar may modify its nutritional composition and produce odorants that alter the ...floral odor bouquet which may attract insect pollinators. Mosquitoes consume nectar and can pollinate flowers. We identified microbes isolated from nectar of common tansy, Tanacetum vulgare, elucidated the microbial odorants, and tested their ability to attract the common house mosquito, Culex pipiens.
We collected 19 microbial isolates from T. vulgare nectar, representing at least 12 different taxa which we identified with 16S or 26S rDNA sequencing as well as by biochemical and physiological tests. Three microorganisms (Lachancea thermotolerans, Micrococcus lactis, Micrococcus luteus) were grown on culture medium and tested in bioassays. Only the yeast L. thermotolerans grown on nectar, malt extract agar, or in synthetic nectar broth significantly attracted Cx. pipiens females. The odorant profile produced by L. thermotolerans varied with the nutritional composition of the culture medium. All three microbes grown separately, but presented concurrently, attracted fewer Cx. pipiens females than L. thermotolerans by itself.
Floral nectar of T. vulgare contains various microbes whose odorants contribute to the odor profile of inflorescences. In addition, L. thermotolerans produced odorants that attract Cx. pipiens females. As the odor profile of L. thermotolerans varied with the composition of the culture medium, we hypothesize that microbe odorants inform nectar-foraging mosquitoes about the availability of certain macro-nutrients which, in turn, affect foraging decisions by mosquitoes.
Cuticular hydrocarbons (CHCs) of social insects have typically been studied for their roles in reproductive signaling (i.e., fertility) rather than sexual signaling (i.e., interest in mating), ...resulting in little information about CHCs of males and virgin females. This dearth of information applies particularly to social wasps. We tested the hypothesis that CHCs differentiate sex, caste, and nest membership in each of four yellowjacket species (baldfaced hornets,
Dolichovespula maculata
; southern yellowjackets,
Vespula squamosa
; western yellowjackets,
V. pensylvanica; V. alascensis
). Cold-euthanized queens (21), gynes (81), workers (125), and males (77) from 35 nests were extracted with pentane, and each of the resulting 304 extracts was analyzed by gas chromatography (GC) and GC–mass spectrometry to identify and quantify CHC constituents (aliphatic alkanes and alkenes; mono-, di-, and tri-methyl-branched alkanes). To determine whether caste and sex differ in CHC profiles of wasps, linear discriminant analyses were performed, using
Z
-transformed relative CHC peak areas as predictor variables and sex and caste, or nest, as grouping variables. When caste and sex were used as a grouping variable, plots of the first two discriminant functions revealed that wasps from each of the four species clustered into their respective groups (queens, gynes, workers, males), with significant differences in group centroids, as measured by Wilks’ lambda. When nest was used as a grouping variable, plots of the first two discriminant functions revealed that workers from each of the four species and males from each of three species (insufficient sample size for
V. pensylvanica
) clustered according to nest. Diagnostic power calculations show greater inter-caste than inter-nest variation. Our data support the above hypothesis and inspire future studies to determine the definitive role(s) that gyne- and male-specific CHCs play in the context of sexual communication, from the perspective of both males and females.
Garlic (Allium sativum) and its essential oil have long been used for their distinct flavour, therapeutic effects and as a topical and systemic insect repellent. We tested the hypothesis that the ...yellow fever mosquito, Aedes aegypti L. (Diptera: Culicidae), responds electrophysiologically and behaviourally to specific components of the steam‐distilled essential oil of garlic. In coupled gas chromatographic‐electroantennographic detection analyses of garlic oil, antennae of female Ae. aegypti responded to 14 compounds. Seven of them diallyl disulphide, diallyl trisulphide, diallyl tetrasulphide, 2‐(2,3‐dithia‐5‐hexenyl)‐3,4‐dihydro‐2H‐thiopyran, 3‐(2,3‐dithia‐5‐hexenyl)‐3,4‐dihydro‐2H‐thiopyran, 6‐methyl‐4,5,8,9‐tetrathiadodeca‐1,11‐diene and 4,5,9,10‐tetrathiatrideca‐1,12‐diene were isolated or synthesized and tested for their ability to repel host‐seeking female Ae. aegypti. A solution of diallyl trisulphide and diallyl tetrasulphide applied to a human forearm provided protection from female mosquitoes significantly longer than the paraffin oil control. All compounds had mean protection times significantly shorter than an equivalent dose of the ‘gold standard’N,N‐diethyl‐3‐methylbenzamide. Understanding the common moiety in organosulfur compounds that causes repellence could lead to the design of analogues that are more effective than their natural counterparts in repelling mosquitoes.
Sex pheromone monitoring lures from five different commercial sources were compared for their attractiveness to male diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae) in canola, ...Brassica napus L., fields in western Canada. Lures that had the highest pheromone release rate, as determined by aeration analyses in the laboratory, were the least attractive in field tests. Lures from all the commercial sources tested released more (Z)-11-hexadecenal than (Z)-11-hexadecenyl acetate and the most attractive lures released a significantly higher aldehyde to acetate ratio than less attractive lures. Traps baited with sex pheromone lures from APTIV Inc. (Portland, OR) and ConTech Enterprises Inc. (Delta, BC, Canada) consistently captured more male diamondback moths than traps baited with lures from the other sources tested, In two different lure longevity field trapping experiments, older lures were more attractive to male diamondback moths than fresh lures. Pheromone release from aged lures was constant at very low release rates. The most attractive commercially available sex pheromone lures tested attracted fewer diamondback moth males than calling virgin female moths suggesting that research on the development of a more attractive synthetic sex pheromone lure is warranted.
Abstract Background Combinations of smaller bone geometry and greater applied loads may contribute to tibial stress fracture. We examined tibial bone stress, accounting for geometry and applied ...loads, in runners with stress fracture. Methods 23 runners with a history of tibial stress fracture & 23 matched controls ran over a force platform while 3-D kinematic and kinetic data were collected. An elliptical model of the distal 1/3 tibia cross section was used to estimate stress at 4 locations (anterior, posterior, medial and lateral). Inner and outer radii for the model were obtained from 2 planar x-ray images. Bone stress differences were assessed using two-factor ANOVA (α = 0.05). Key contributors to observed stress differences between groups were examined using stepwise regression. Findings Runners with tibial stress fracture experienced greater anterior tension and posterior compression at the distal tibia. Location, but not group, differences in shear stress were observed. Stepwise regression revealed that anterior–posterior outer diameter of the tibia and the sagittal plane bending moment explained > 80% of the variance in anterior and posterior bone stress. Interpretation Runners with tibial stress fracture displayed greater stress anteriorly and posteriorly at the distal tibia. Elevated tibial stress was associated with smaller bone geometry and greater bending moments about the medial–lateral axis of the tibia. Future research needs to identify key running mechanics associated with the sagittal plane bending moment at the distal tibia as well as to identify ways to improve bone geometry in runners in order to better guide preventative and rehabilitative efforts.
Analyses of pooled headspace volatiles from three commercial chili pepper, Capsicum spp., products by coupled gas chromatographic-electroantennographic detection (GC-EAD) and coupled GC-mass ...spectrometry (MS) revealed 10 compounds (β-pinene, γ-terpinene, linalool, 2-phenylethanol, cumin aldehyde, 1,3-menthadienal, eugenol, trans-β-caryophyllene, caryophyllene oxide, and an unknown compound which co-eluted with 2-phenylethanol) that elicited responses from the antennae of cigarette beetles, Lasioderma serricorne. The unknown compound was separated by silica fractionation and identified by MS and NMR spectroscopy as 2-hydroxy-2,6,6-trimethyl-cyclohexanone. In Y-tube olfactometer bioassays, beetles were attracted to the 10-component synthetic blend and to many six- and four-component blends, demonstrating widespread redundancy in bioactivity among the components. Eugenol was discounted as an attractant, whereas β-caryophyllene and linalool had previously been identified as kairomones for L. serricorne. The remaining seven compounds are novel host kairomones for L. serricorne, bringing the total of known host kairomones for this species to 18. The redundancy among host kairomones may enable L. serricorne to find and infest many highly variable stored products, any one of which may emit only a few of the known kairomones.
•Ten potential host attractants (kairomones) for the cigarette beetle were identified in the pooled captured volatiles from three commercial chili pepper products.•Seven of the 10 identified compounds are novel, bringing the total number of known kairomones to 18.•Blends of 6, 4 and 3 of the 10 synthetic compounds in various combinations were as attractive, indicating remarkable redundancy.•Ability to respond to many compounds may enable cigarette beetles to find diverse hosts, any one of which may emit only a few of the 18 known kairomones.
The red clover casebearer, Coleophora deauratella Lienig & Zeller (Lepidoptera: Coleophoridae), is an invasive pest of Trifolium species (Fabaceae) in Canada. We identified candidate sex pheromone ...components from female pheromone gland extracts using coupled gas chromatographic-electroantennographic analysis detection. Three compounds elicited an electrophysiological response from antennae and were identified as: (Z)‐7‐dodecenyl acetate, (Z)‐5‐dodecenyl acetate, and (Z)‐7‐dodecen‐1‐ol. Field tests of the candidate pheromone components revealed that males were attracted to a binary mixture of (Z)‐7‐dodecenyl acetate and (Z)‐5‐dodecenyl acetate. Male moth trap capture was greatest in traps baited with lures containing 100:10 or 100:20 ratios of these pheromone components, respectively. Trap capture was reduced when (Z)‐5‐dodecenyl acetate was present below 10 or above 20% of (Z)‐7‐dodecenyl acetate. Equal numbers of male moths were captured in traps baited with 10, 100, and 1 000 μg of the attractive binary mixture. These findings allow for the development of a pheromone‐based monitoring system for this invasive pest of clover in Canada.
A biodegradable attracticide formulation containing the pyrethroid insecticide permethrin and the sex pheromone of the ash leaf cone roller, Caloptilia fraxinella (Ely) (Lepidoptera: Gracillariidae), ...was tested for attractiveness and toxicity to males of this invasive pest of horticultural ash, Fraxinus spp. Marsh. (Oleaceae). Trap capture in attracticide‐baited traps was equal to capture in traps baited with rubber septa lures releasing the known attractive pheromone. Pheromone response by male C. fraxinella was not affected by the presence of permethrin as equal numbers of males were captured in traps baited with the attracticide formulation with and without permethrin. Attraction to the attracticide containing both pheromone and insecticide active ingredients did not vary with dose as 10, 50, and 100 mg droplets of the formulation attracted similar numbers of male moths in a field experiment. Equal numbers of male moths were captured in traps baited with droplets that had aged for 0–5 weeks in a laboratory fume hood before deployment in the field. The permethrin constituent of the attracticide formulation was toxic to male moths treated through tarsal contact and resulted in 73 and 100% mortality at 24 and 72 h post‐treatment, respectively. Leg autotomy occurred in over 80% of males 24 h post‐treatment to formulations containing permethrin. Mortality of moths was greater 24 h after treatment with a fresh attracticide source as compared to a 5‐week‐old source. However, mortality as a result of treatment with fresh and aged attracticide droplets was equal at 48, 72, and 96 h post‐treatment. This formulation has the potential to become a useful tool in an integrated pest‐management system for C. fraxinella on horticultural ash.
To determine oxyhemoglobin saturation (O2 Sat) in healthy humans.
Retrospective review of all-night pulse oximetry data, carefully examined to exclude periods of motion artifact. The lowest ...saturation recorded during the night (Low Sat), the median saturation (Sat 50), and the saturation below which the patient spent 10% of the time (Sat 10) were tabulated. These data were compared to the O2 Sat in patients with obstructive sleep apnea (OSA) and patients with stable asthma.
Sleep laboratory in a tertiary care hospital.
Three hundred fifty people with normal results of overnight polysomnography. Patients with known craniofacial or neurologic abnormalities or any previously diagnosed pulmonary disease such as asthma or COPD were excluded. The healthy subjects ranged in age from 1 month to 85 years. There were 184 male and 166 female subjects. These were compared to 25 patients with OSA and 21 patients with asthma.
For the healthy patients, the mean +/- SD Low Sat was 90.4% +/- 3.1%. The mean Sat 10 was 94.7% +/- 1.6%. The mean Sat 50 was 96.5% +/- 1.5%. There was no relationship between any of the O2 Sat measures and sex, race, or obesity as measured by body mass index. However, older subjects (> 60 years of age) had lower Sat 10 (92.8 +/- 2.3) and Sat 50 (95.1 +/- 2.0) than did younger subjects. The O2 Sat of the patients with asthma was not different from the healthy subjects, but the patients with OSA had a significantly lower Sat 50, Sat 10, and Low Sat.
We describe in detail O2 Sat in a large group of healthy people. Older subjects without known cardiorespiratory disease have lower O2 Sat than younger subjects.
PDF
