Analysis Of Headspace Volatiles Research Articles

Fungal contamination and mycotoxins in aquafeed and tissues of aquaculture fishes and their biological control

The presence of mycotoxins in food and feed is a significant issue, especially in fish farming where it can negatively impact farmed fish species. In this study, samples of aquaculture feed and fishes tissues were collected for fungal isolation and mycotoxins analysis. Levels of aflatoxins (AFs) and ochratoxin A (OTA) in the muscles and organ (liver and kidneys) were compared in three fish species. Furthermore, the volatile organic compounds (VOCs) emitted from a novel Bacillus cereus BC344–2 strain were tested against the growth and mycotoxin production of Penicillium spp., Aspergillus spp., and Fusarium species. There was a moderate fungal load in the aquafeed with 1.30 × 102 ± 2.6 × 102 (mean ± SD) CFU/g with high contribution of Aspergillus and Penicillium fungi. OTA and AFs were detected in 95% and 66.7% of the tested aquafeed samples, respectively, with 66.7% of the samples co-contaminated with both mycotoxins. Although AFs contents were within permissible limits, 4.8% of samples showed OTA contamination exceeding the permissible limits (5 μg/kg). Both mycotoxins were found in the liver samples, but none of the fish meat (muscle) samples were found to be contaminated with OTA. The in vitro biocontrol co-incubation assay showed that BC344–2 VOCs had a significant inhibitory effect on the growth and sporulation of the three exposed fungi. P. verrucosum showed the highest sensitivity with a 42.4% inhibition ratio, followed by F. solani (17.5%) and A. flavus (11.5%). Additionally, BC344–2 VOCs suppressed OTA and AFs synthesis by P. verrucosum and A. flavus, respectively. Gas chromatography-based analysis of headspace volatiles in BC344–2 volatilome revealed five bioactive compounds with BTH aldehyde and 1-Heptadecanol being the most probable antifungal compounds responsible for the inhibitions. Given the high detection rate of OTA and AFs in the fish tissue and feed samples, along with regular monitoring of mycotoxins, the biocontrol approaches using bacterial volatiles such as BC344–2 VOCs could be useful to ensure feed and food safety.

Response of some mango-infesting fruit flies to aqueous solutions of the basil plant Ocimum tenuiflorum L

IntroductionHorticulture is an important sub-sector for many African countries. Tephritid fruit flies continue to cause serious direct and indirect damage to the sub-sector. The male annihilation technique (MAT) using methyl eugenol (ME) is among the most revered techniques in fruit fly management. However, ME-based lures are only available to some farmers in Africa. Several basils of the genus Ocimum produce ME.MethodsIn laboratory experiments, we used a dual choice olfactometer to assess the attraction of adult oriental fruit fly Bactrocera dorsalis to intact plants, 100 µL commercial methyl eugenol (ME) (positive control), 10 mg/mL of O. tenuiflorum aqueous extract (Otae), and a negative control (blank). Large arena experiments were conducted to compare the responses of four fruit fly species of economic importance in Africa to Otae-baited traps.ResultsIn dual choice olfactometer assay, more B. dorsalis males (78.6%) than females (23.8%) were attracted to Otae. Most B. dorsalis males were attracted to the positive control (90.5%) and 10 mg/mL Otae (88.5%) compared to the whole plant (84.0%). In large arena experiments, Otae attracted the most B. dorsalis males (47.7%), followed by Zeugodacus cucurbitae males (25.1%), while males of Ceratitis species were the least attracted. The analysis of headspace volatiles from aerial plants, Otae and essential oil using gas chromatography-mass spectrometry detected 97 compounds. The intact plant without flowers, intact plant with flowers, Otae, and the O. tenuiflorum essential oil contributed 76, 62, 33 and 28 compounds, respectively. ME comprised the top three most abundant compounds, especially in the essential oil.DiscussionOur study confirms the potential of O. tenuiflorum as a source of ME for tephritid fruit fly integrated management in Africa. Otae, a readily available alternative to commercial ME, can be used to develop fruit fly-baited traps, particularly for smallholder farmers.

Attractive host kairomones for the cigarette beetle, Lasioderma serricorne (Coleoptera: Anobiidae)

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.

Ridge gourd volatiles are attractive to gravid female melon fly, Zeugodacus cucurbitae (Coquillett) (Diptera: Tephritidae)

AbstractThe melon fruit fly, Zeugodacus cucurbitae (Coquillett) (Diptera: Tephritidae), is an important pest of cucurbits throughout India, South‐East Asia and Pacific islands. Attractants of female melon fly are of relevance as they could enhance the efficacy of current pest management practices. Previous studies have revealed several host fruits to be attractive to gravid female melon flies. However, studies on the chemical compounds responsible for their attraction are meagre. As an initial part of our study, we evaluated the response of gravid female melon flies to headspace volatiles of four different cucurbit fruits, namely bitter gourd, cucumber, ridge gourd and snake gourd. Electrophysiological and multiple‐choice olfactometer assays revealed that gravid melon flies significantly preferred ridge gourd volatiles over volatiles of other cucurbit fruits. Coupled gas chromatography‐electroantennogram detection (GC‐EAG) analysis of headspace volatiles of ridge gourd to gravid melon flies identified six EAG‐active compounds, namely α‐pinene, 1‐octen‐3‐ol, p‐cymene, p‐ethyl‐benzaldehyde, methyl salicylate and p‐cymen‐7‐ol. Individual EAG‐active compounds, except α‐pinene, were significantly attractive to gravid female flies. Moreover, a synthetic blend with the concentration and ratio of compounds as in the ridge gourd headspace samples was attractive to flies. Though, in a dual‐choice test, the preference of gravid melon flies to a synthetic blend was not significantly different from preference to ridge gourd volatile samples. Taken together, our results show that the synthetic blend of ridge gourd volatiles may be used to develop a potential lure for female melon fly, Z. cucurbitae.

Retention of freshness and isothiocyanates in fresh-cut radish (Raphanus sativus var. Longipinnatus) through glucose dip treatment.

The online version contains supplementary material available at 10.1007/s13197-021-05276-1.

Prevalence of toxigenic fungi and mycotoxins in Arabic coffee (Coffea arabica): Protective role of traditional coffee roasting, brewing and bacterial volatiles.

Fungal infection and synthesis of mycotoxins in coffee leads to significant economic losses. This study aimed to investigate the prevalence of toxigenic fungi, their metabolites, and the effect of traditional roasting and brewing on ochratoxin A (OTA) and aflatoxins (AFs) contents of naturally contaminated coffee samples. In addition, in vivo biocontrol assays were performed to explore the antagonistic activities of Bacillus simplex 350–3 (BS350-3) on the growth and mycotoxins synthesis of Aspergillus ochraceus and A. flavus. The relative density of A. niger, A. flavus, Penicillium verrucosum and A. carbonarius on green coffee bean was 60.82%, 7.21%, 3.09% and 1.03%, respectively. OTA contents were lowest in green coffee beans (2.15 μg/kg), followed by roasted (2.76 μg/kg) and soluble coffee (8.95 μg/kg). Likewise, AFs levels were highest in soluble coffee (90.58 μg/kg) followed by roasted (33.61 μg/kg) and green coffee (9.07 μg/kg). Roasting naturally contaminated coffee beans at three traditional methods; low, medium and high, followed by brewing resulted in reduction of 58.74% (3.50 μg/kg), 60.88% (3.72 μg/kg) and 64.70% (4.11 μg/kg) in OTA and 40.18% (34.65 μg/kg), 47.86% (41.17 μg/kg) and 62.38% (53.73 μg/kg) AFs contents, respectively. Significant inhibitions of AFs and OTA synthesis by A. flavus and A. carbonarius, respectively, on infected coffee beans were observed in presence of Bacillus simplex BS350-3 volatiles. Gas chromatography mass spectrochemistry (GC-MS/MS) analysis of head-space BS350-3 volatiles showed quinoline, benzenemethanamine and 1-Octadecene as bioactive antifungal molecules. These findings suggest that marketed coffee samples are generally contaminated with OTA and AFs, with a significant level of roasted and soluble coffee contaminated above EU permissible limits for OTA. Further, along with coffee roasting and brewing; microbial volatiles can be optimized to minimize the dietary exposure to mycotoxins.

Identification of Pheromone Components of Plagionotus detritus (Coleoptera: Cerambycidae), and Attraction of Conspecifics, Competitors, and Natural Enemies to the Pheromone Blend.

Simple SummaryThe longhorn beetle, Plagionotus detritus (L.), occurs throughout Europe and into the Middle East. Our principal aim was to identify the male-produced aggregation-sex attractant pheromone of this species. A pheromone-based monitoring system could support plant protection in areas where it might become a pest and natural conservation in areas where it is endangered. Headspace volatiles were collected from live beetles and analyzed by coupled gas chromatography-electroantennogram detection and gas chromatography-mass spectrometry. Two components of the extracts that elicited responses from antennae of P. detritus, (R)-3-hydroxyhexan-2-one and (S)-2-hydroxyoctan-3-one were identified, (±)-3-hydroxyhexan-2-one was purchased, and (S)-2-hydroxyoctan-3-one was synthesized, and field-tested. The blend of the two components attracted both sexes of P. detritus in field bioassays. Unexpectedly, a predatory clerid beetle, Clerus mutillarius F., was also attracted by both of the synthetic compounds. Another longhorn beetle species, Xylotrechus antilope Schönh. was significantly attracted to traps baited with (S)-2-hydroxyoctan-3-one alone or the blend containing this compound. These results show that the pheromone components and combinations play key roles in longhorn beetle life history and ecology, and the community of species in which they live.(1) Background: The principal aim of our work was to identify pheromone components for Plagionotus detritus (L.) (Coleoptera: Cerambycidae), which could be exploited for developing a pheromone-based monitoring system for the complementary purposes of plant protection in areas where it might become a pest, and natural conservation in areas where it is rare or endangered. (2) Methods: Collection and analysis of headspace volatiles were carried out with field-collected beetles. Bioactive volatile compounds identified [(R)-3-hydroxyhexan-2-one and (S)-2-hydroxyoctan-3-one] from extracts of males were purchased [(±)-3-hydroxyhexan-2-one], and synthesized [(S)-2-hydroxyoctan-3-one] and field-tested. Electroantennogram assays showed that antennae of the predatory beetle Clerus mutillarius F. (Coleoptera: Cleridae) also responded to the synthetic compounds. (3) Results: A two-component aggregation-sex pheromone consisting of (R)-3-hydroxyhexan-2-one and (S)-2-hydroxyoctan-3-one was identified for P. detritus. (±)-3-hydroxyhexan-2-one and (S)-2-hydroxyoctan-3-one attracted adults of P. detritus in field bioassays. Adults of the clerid C. mutillarius also were attracted to both compounds. The cerambycid Xylotrechus antilope Schönh was significantly attracted to traps baited with (S)-2-hydroxyoctan-3-one alone or the blend containing this compound. (4) Conclusions: Our data confirmed that 3-hydroxyhexan-2-one and 2-hydroxyoctan-3-one are male-produced pheromone components for P. detritus. These results show that both intraspecific and interspecific communication may play key roles in longhorn beetle life history and ecology, with closely and more distantly related species eavesdropping on each other’s signals.

Reducing off-flavors in plant-based omega-3 oil emulsions using interfacial engineering: Coating algae oil droplets with pea protein/flaxseed gum

Algae oil is a sustainable source of health-promoting docosahexaenoic acid (DHA) suitable for vegans and vegetarians, but it has poor water-solubility and is prone to lipid oxidation, which leads to unpleasant off flavors. In this research, emulsion technology was used to create a plant-based DHA delivery system consisting of algae oil droplets coated by pea protein (PP) and flaxseed gum (FG). The pea protein was used as an emulsifier, while the flaxseed gum was deposited onto the protein-coated droplets by electrostatic deposition. The PP-FG interactions were investigated in solution and at the oil-water interface. Stable PP/FG-coated oil droplets were formed when the FG concentration was high enough to saturate the PP-coated droplet. Transmission electron microscopy showed that the interfacial thickness increased with increasing FG concentration. The oil-water interfacial tension of the PP/FG complex (14.6 nN/m) was slightly lower than that of the PP alone (18.7 nN/m), which suggests that the presence of the polysaccharide increased the surface activity. Furthermore, analysis of headspace volatiles showed that the presence of the interfacial coating could reduce the undesirable fishy smell of algae oil, i.e., low heptanal and (E, Z)-3,5-octadiene-2-one levels. This phenomenon was attributed to the ability of the interfacial coatings to inhibit lipid oxidation or reduce off flavor release from the oil droplets. The plant-based emulsions produced in this study may therefore be suitable as effective ω-3 fatty acid delivery systems that can be incorporated into functional foods and beverages.

Biocontrol Activity of Bacillus megaterium BM344-1 against Toxigenic Fungi.

Mycotoxins are secondary metabolites of some fungal species and represent important contaminants of food and feed. This study aimed to explore the biological control activity of Bacillus megaterium BM344-1 volatile organic compounds (VOCs) on the growth and mycotoxin production of single representatives of the toxigenic species Aspergillus flavus, Aspergillus carbonarius, Penicillium verrucosum, and Fusarium verticillioides. In vitro co-incubation experiments indicated the P. verrucosum isolate as the most sensitive one, with a growth inhibition ratio of 66.7%, followed by A. flavus (29.4%) and F. verticillioides (18.2%). Exposure of A. flavus, P. verrucosum, and F. verticillioides to BM344-1 VOCs resulted in complete inhibition of aflatoxins (AFB1, AFG1, and AFG2), ochratoxin A, and fumonisin B1 (FB1) synthesis on artificial media, respectively. In vivo experiments on maize kernels showed 51% inhibition of fungal growth on ears simultaneously infected with A. flavus spores and exposed to BM344-1 volatiles. Likewise, AF synthesis by A. flavus was significantly (p < 0.05) inhibited (25.34 ± 6.72 μg/kg) by bacterial volatiles as compared to that in control maize ears (91.81 ± 29.10 μg/kg). Gas chromatography–tandem mass spectrometry-based analysis of headspace volatiles revealed hexadecanoic acid methyl ester (palmitic acid) and tetracosane as bioactive compounds in the BM344-1 volatilome. Bacterial volatiles have promising potential to control the growth and mycotoxin synthesis of toxigenic fungi and may present valuable aid in the efforts to warrant food and feed safety.

Fruit volatiles mediate differential attraction of Drosophila suzukii to wild and cultivated blueberries

Native to the northeast USA, highbush blueberry is a crop domesticated for close to 100 years and that has been selected mainly for high yields and bigger fruit. We hypothesized that, due to domestication and associated agronomic selection (i.e., cultivation practices), cultivated blueberries differ from their wild ancestors in fruit volatile emissions, affecting the response of a frugivorous pest. To test this hypothesis, we compared the attraction of adult spotted-wing drosophila (Drosophila suzukii) to wild and cultivated blueberry fruit volatiles in choice assays. We also conducted headspace volatile chemical analysis and electroantennographic detection (EAD) analysis to identify and quantify any antennally active compounds. For this, fruit from wild and cultivated blueberries, growing in proximity, was sampled from six farms located in the Pinelands National Reserve (New Jersey, USA)—a blueberry-producing region with a forest understory consisting largely of wild blueberries. On a per gram basis, we found that wild blueberries are more attractive to D. suzukii flies and have higher volatile emission rates than cultivated blueberries. Nine EAD-active compounds from wild blueberries (isobutyl acetate, ethyl butyrate, ethyl 2-methylbutyrate, ethyl 3-methylbutyrate, hexanal, isoamyl acetate, 3-hydroxybutanone (acetoin), 6-methyl-5-hepten-2-one, and 1-hexanol) were attractive individually and as a blend to D. suzukii flies. However, a 4-component blend composed of isoamyl acetate, acetoin, 6-methyl-5-hepten-2-one, and 1-hexanol was more attractive to D. suzukii than the 9-component blend. Altogether, our results show that the domestication/cultivation of blueberries is associated with lower rates of fruit volatile emissions, which has resulted in decreased attraction of a frugivorous pest, D. suzukii.

Antioxidant Activity of Osage Orange Extract in Soybean Oil and Fish Oil during Storage

AbstractThe food industry is seeking natural antioxidants for edible oils that have comparable activity to synthetic counterparts. In this study, Osage orange extract (OOE) rich in osajin (42.9%) and pomiferin (30.0%) was obtained after hexane extraction of the fruit, and its antioxidant activity was examined in stripped soybean oil (SBO) and fish oil (FO), in which antioxidants and polar compounds were removed. The antioxidant activity of OOE was compared with commercial natural antioxidants (i.e., rosemary extract and mixed tocopherols) and a synthetic antioxidant, butylated hydroxytoluene (BHT), during storage at 25 and 40 °C. The 0.1% OOE had stronger antioxidant activity than 0.1% rosemary extract and 0.1% mixed tocopherols in both oils at 25 and 40 °C. Its activity was similar to 0.02% BHT in SBO and was similar or slightly stronger than 0.02% BHT in FO. When OOE was studied at 0.05, 0.1, and 0.2%, there was a weak dose–response in SBO but a stronger dose–response in FO. Headspace volatile analysis using solid phase micro‐extraction (SPME) combined with GC–MS indicated that 0.1% OOE was very effective in preventing the formation of volatile oxidation products in both oils. Although it should be further tested for safety before the actual use, this study shows that OOE can be developed as an antioxidant for edible oils.

Profiles of the Essential Oils and Headspace Analysis of Volatiles from Mandragora autumnalis Growing Wild in Tunisia.

Mandragora autumnalis Bertol. (Solanaceae family), synonym of M. officinalis Mill., occurs in North Africa and grows natively in Northern and Central Tunisia, in humid to sub-arid climates. The ripe fruits of mandrake are odiferous with a particular, indescribable, specific odor, shared, to a lesser extent, by the leaves and roots. We carried out an investigation of the essential oils (EOs) and of the aromatic volatiles emitted by fresh leaves, roots and ripe fruits of M. autumnalis growing wild in Central Tunisia. The EOs were obtained from freshly collected plant material by hydrodistillation, while the volatile emissions from the powdered M. autumnalis tissues were sampled by headspace solid phase microextraction (HS-SPME); both types of samples were analyzed by gas chromatography-mass spectrometry (GC/MS). Fifty-one compounds representing 96.2-98.6 % of the total oil compositions were identified in the three tissues and belonged to different chemical classes specifically in 16 esters, 12 alcohols, 12 hydrocarbons, 6 ketones, 3 aldehydes and 3 acids. The main constituents were pentadecanoic acid (34.2 %) and hexadecanol (26.3 %). A total of 78 volatile compounds emanating from M. autumnalis tissues, representing 94.1-96.4 % of the total volatile compositions, were identified: 22 esters, 11 alcohols, 9 aldehydes, 14 ketones, 7 nitrogen, 10 hydrocarbons, 2 lactones, 1 sulfur and 2 ethers. Ethyl hexanoate (12.3 %) and 1,3-butanediol (12.3 %) were at the highest relative percentages. This study characterizes and distinguishes M. autumnalis from Tunisia and attributes the compounds responsible for the intoxicating and particular odor of fruits. Chemosystematic of Mandragora autumnalis based on the identification of essential oils and headspace volatiles of each of its organ can be used to characterize this species according to its geographic distribution.

Common Cerambycid Pheromone Components as Attractants for Longhorn Beetles (Cerambycidae) Breeding in Ephemeral Oak Substrates in Northern Europe

Longhorn beetles are ecologically important insects in forest ecosystems as decomposers of woody substrates, microhabitat engineers, and as components of forest food webs. These species can be greatly affected both positively and negatively by modern forestry management practices, and should be monitored accordingly. Through headspace sampling, coupled gas chromatography-electroantennography, gas chromatography-mass spectrometry, and field bioassays, we identified two compounds, 2-methyl-1-butanol and 3-hydroxy-2-hexanone, that constitute aggregation-sex pheromone attractants of three cerambycid species which breed primarily in different types of fresh, recently dead oak wood in Northern Europe: Pyrrhidium sanguineum (L.), Phymatodes alni ssp. alni (L.), and Phymatodes testaceus (L.) (Cerambycinae: Callidiini). Analyses of headspace volatiles collected from live insects indicated that the male-produced aggregation-sex pheromone of P. sanguineum is a 1–15:100 blend of (R)-2-methyl-1-butanol and (R)-3-hydroxy-2-hexanone, whereas the corresponding ratios for P. alni were 70–110:100. In field bioassays, adult P. sanguineum and P. alni were significantly attracted to multiple blends with varying ratios of the two compounds. When tested individually, the compounds were minimally attractive. In contrast, adult P. testaceus exhibited nonspecific attraction to both of the individual compounds and to different blends, despite the hydroxyketone not being part of its pheromone, which consists of (R)-2-methyl-1-butanol alone. Overall, our results suggest that a blend of 50:100 of racemic 2-methyl-1-butanol and 3-hydroxy-2-hexanone is appropriate for parallel, cost-efficient pheromone-based monitoring of all three species. In particular, these species could serve as useful indicators of how modern forestry practices affect a whole guild of saproxylic insects that require ephemeral deadwood substrates for successful breeding.

Host Selection, Oviposition and Feeding by a Phytopathogen Vector, Diaphorina citri (Hemiptera: Liviidae), Modulated by Plant Exposure to Formic Acid

Citrus volatiles and their breakdown products, such as formic and acetic acids, guide host finding by Asian citrus psyllids (Diaphorina citri). Formic acid elicits psyllid antennal responses and stimulates probing. This study investigated how exposure to vapor phase formic acid induced changes in plant volatile emissions, expression of plant defense genes, and modified psyllid host finding and feeding behaviors on susceptible and resistant citrus cultivars. Chemical analyses of headspace volatiles and behavioral assays were performed before and after exposure of D. citri susceptible and resistant plants to vapor phase formic acid. RT-qPCR elucidated changes in plant defense-associated gene expression following exposure. Electrical Penetration Graph (EPG) measured D. citri feeding behavior on citrus with and without exposure to formic acid. Volatilized formic acid caused a 200-500% increase in release of citrus volatiles 1-3 hours after exposure, increased attraction of D. citri to Poncirus trifoliata (resistant) and increased oviposition compared with controls. RT-qPCR showed significant increases in expression of WRKY22, GST1, RAR1 and EDS1 genes following exposure that also reduced phloem, but not xylem, ingestion by adult D. citri. Formic acid exposure caused increased citrus volatile release that modified host finding and feeding behaviors of an important phytopathogen vector.

Antioxidant Activity of Spent Coffee Ground Extracts Toward Soybean Oil and Fish Oil

Although studies have shown that spent coffee ground (SCG) extracts have antioxidant activity, no systematic study has been reported under actual storage conditions. The purpose of this study is to estimate the feasibility of practical application of SCG extracts as natural antioxidants for soybean oil and fish oil. An ethanol extract (EE), an acetone extract (AE), and polar compounds isolated from oil (PCO) are prepared and their activity is compared to a synthetic antioxidant, butylated hydroxytoluene (BHT). EE shows the strongest radical scavenging activity for 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radicals and the highest total phenolic content (TPC) followed by AE and then PCO. However, during storage of soybean oil and fish oil at 35 and 50 °C, AE has the strongest antioxidant activity as determined by peroxide value, conjugated diene value, p‐anisidine value, and headspace volatile analyses. In soybean oil, 0.25% AE has antioxidant activity that is equal to or better than 0.02% BHT. In fish oil, the antioxidant activity of 0.25% AE is inferior to that of 0.02% BHT. However, increased concentrations of AE show improved antioxidant activity. This study shows that SCG extracts can be practically used as natural antioxidants for vegetable oils and omega‐3 oils.Practical Application: Due to lack of information about the antioxidant activity of spent coffee ground (SCG) extracts, this study is specifically aimed and designed to provide information on their activity toward soybean oil and fish oil during actual storage. This study shows that 0.25% acetone extract has equal or better protective effects than BHT in soybean oil at 35 and 50 °C. The activity is further improved with increasing concentration. The activity of the acetone extract in fish oil is not as strong as in soybean oil, but higher concentrations further improve the antioxidant activity. In this study, it is clearly demonstrated that the SCG extracts can have practical use as natural antioxidants for vegetable oils and oils with high concentration of omega‐3 fatty acids.Among spent coffee ground (SCG) extracts, the acetone extract (AE) has the strongest antioxidant activity. In soybean oil, 0.25% AE has antioxidant activity that is equal to or better than 0.02% butylated hydroxytoluene (BHT). This study shows that SCG extracts can be practically used as natural antioxidants for edible oils.

The Beneficial Endophytic Fungus Fusarium solani Strain K Alters Tomato Responses Against Spider Mites to the Benefit of the Plant.

Beneficial microorganisms are known to promote plant growth and confer resistance to biotic and abiotic stressors. Soil-borne beneficial microbes in particular have shown potential in protecting plants against pathogens and herbivores via the elicitation of plant responses. In this study, we evaluated the role of Fusarium solani strain K (FsK) in altering plant responses to the two spotted spider mite Tetranychus urticae in tomato. We found evidence that FsK, a beneficial endophytic fungal strain isolated from the roots of tomato plants grown on suppressive compost, affects both direct and indirect tomato defenses against spider mites. Defense-related genes were differentially expressed on FsK-colonized plants after spider mite infestation compared to clean or spider mite-infested un-colonized plants. In accordance, spider mite performance was negatively affected on FsK-colonized plants and feeding damage was lower on these compared to control plants. Notably, FsK-colonization led to increased plant biomass to both spider mite-infested and un-infested plants. FsK was shown to enhance indirect tomato defense as FsK-colonized plants attracted more predators than un-colonized plants. In accordance, headspace volatile analysis revealed significant differences between the volatiles emitted by FsK-colonized plants in response to attack by spider mites. Our results highlight the role of endophytic fungi in shaping plant–mite interactions and may offer the opportunity for the development of a novel tool for spider mite control.

(E,E)-α-Farnesene as a host-induced plant volatile that attracts Apanteles taragamae (Hymenoptera: Braconidae) to host-infested cucumber plants

ABSTRACTIn tritrophic interactions between cucumber plants, the cucumber moth Diaphania indica Saunders (Lepidoptera: Crambidae) and a larval parasitoid Apanteles taragamae Viereck (Hymenoptera: Braconidae), female A. taragamae may use herbivore-induced plant volatiles (HIPVs) to locate their host. However, the specific compound or blend of chemicals attracting A. taragamae remains unknown. In this study, differences in volatiles released from uninfested, mechanically damaged and host-infested cucumber plants were examined by the headspace volatile collection method. Responses of the larval parasitoid A. taragamae to the volatile extracts were examined in a four-arm olfactometer. We also investigated the attraction of female A. taragamae to a single compound identified as an HIPV from host-infested cucumber plants. Parasitoids discriminated between the volatiles from uninfested, host-infested and mechanically damaged plants. Chemical analysis of headspace volatiles from host-infested cucumber plants showed that (E,E)-α-farnesene was released as a major component (73.1%). When (E,E)-α-farnesene was tested alone in the range of 1.7–170 ng, female parasitoids responded to 17 ng only. Therefore, tritrophic interactions between A. taragamae and D. indica appear to be partly mediated by (E,E)-α-farnesene.

Aggregation-Sex Pheromones and Likely Pheromones of 11 South American Cerambycid Beetles, and Partitioning of Pheromone Channels

Over the past decade, volatile sex and/or aggregation pheromones and pheromone candidates have been identified for well over 100 species in the large beetle family Cerambycidae, demonstrating that pheromone-based communication is crucial for effective mate location by these insects. Despite this rapid progress in elucidating the chemical ecology of Cerambycidae, most research to date has focused on species from North America, Europe, and Asia, with almost nothing known about species native to Africa, Australia, and South America. Here, we report the identification and field assessment of aggregation-sex pheromones produced by adult males of Ambonus distinctus (Newman) and Ambonus electus (Gahan), two sympatric and synchronic cerambycid species endemic to South America. Analyses of headspace volatiles from adult beetles showed that these species share two male-specific components, (R)-3-hydroxyhexan-2-one, and lesser amounts of 1-(1H-pyrrol-2-yl)-1,2-propanedione. Headspace volatiles from male A. distinctus also contained a novel minor component, identified as 3-methylthiopropan-1-ol. Field bioassays were conducted in Brazil, testing reconstructed blends of the compounds produced by each species, as well as racemic 3-hydroxyhexan-2-one and 1-(1H-pyrrol-2-yl)-1,2-propanedione as single components. Both sexes of A. distinctus and A. electus were most attracted to traps baited with their respective blends. In particular, 3-methylthiopropan-1-ol synergized attraction of A. distinctus and appeared to antagonize attraction of A. electus, suggesting a mechanism to minimize cross-attraction between these two congeners. Nine other cerambycid species were captured in significant numbers during the bioassays, including Ambonus interrogationis (Blanchard), Amorupi fulvoterminata (Berg), Chrysoprasis aurigena (Germar), Itaclytus olivaceus (Laporte & Gory), Neoclytus pusillus (Laporte & Gory), Orthostoma abdominale (Gyllenhal), Sphaerion inerme White, Stizocera consobrina Gounelle, and Uncieburia nigricans (Gounelle). Males of some of these species were found to produce (R)-3-hydroxyhexan-2-one, explaining why they had been attracted to some of the lures tested in bioassays. However, males of other species produced compounds other than 3-hydroxyhexan-2-one or 1-(1H-pyrrol-2-yl)-1,2-propanedione. We propose that these species are exploiting the pheromones of other guild members to locate high quality hosts for their larvae.

Effect of Male House Mouse Pheromone Components on Behavioral Responses of Mice in Laboratory and Field Experiments.

Urine of male house mice, Mus musculus, is known to have primer pheromone effects on the reproductive physiology of female mice. Urine-mediated releaser pheromone effects that trigger certain behavioral responses are much less understood, and no field studies have investigated whether urine deposits by male or female mice, or synthetic mouse pheromone, increase trap captures of mice. In field experiments, we baited traps with bedding soiled with urine and feces of caged female or male mice, and recorded captures of mice in these and in control traps containing clean bedding. Traps baited with female bedding preferentially captured adult males, whereas traps baited with male bedding preferentially captured juvenile and adult females, indicating the presence of male- and female-specific sex pheromones in soiled bedding. Analyses of headspace volatiles emanating from soiled bedding by gas chromatography/mass spectrometry revealed that 3,4-dehydro-exo-brevicomin (DEB) was seven times more prevalent in male bedding and that 2-sec-butyl-4,5-dihydrothiazole (DHT) was male-specific. In a follow-up field experiment, traps baited with DEB and DHT captured 4 times more female mice than corresponding control traps, thus indicating that DEB and DHT are sex attractant pheromone components of house mouse males. Our study provides impetus to identify the sex attractant pheromone of female mice, and to develop synthetic mouse pheromone as a lure to enhance the efficacy of trapping programs for mouse control.

Male-specific volatiles released by Homalinotus validus (Coleoptera: Curculionidae) include (1R,2S)-grandisyl acetate, a new natural product

Homalinotus validus is an important pest of babassu palm (Attalea speciosa) cultures in North Brazil. Investigations on the chemical ecology of this species are essential for the development of an integrated pest management system, since attempts to control the pest by conventional insecticides failed. GC/MS and GC/FT-IR analyses of headspace volatiles obtained from males and females revealed the presence of two male specific compounds, which were identified to be (1R,2S)-grandisol and the new (1R,2S)-grandisyl acetate. Both compounds presumably act as an aggregation pheromone of the species.