Search Results (47)

Plants and insects are developing strategies to avoid each other’s defense systems. Host plants may release volatile compounds to attract the natural enemies of herbivores; insect pests may also select host plants that are deterrent to natural enemies to avoid such predation. Here we investigated whether the host plant preference of Hyphantria cunea correlates with the attractiveness of these plants to Chouioia cunea, a parasitoid wasp that serves as the primary natural enemy of H. cunea. We found Morus alba was the preferred host plant for female H. cunea. Although M. alba provided suboptimal nutritional value for H. cunea growth and development compared to other plants, it attracted fewer C. cunea relative to alternative host plants. Gas chromatography–mass spectrometry (GC–MS) coupled with gas chromatography–electroantennographic detection (GC-EAD) analysis identified six distinct compounds among the herbivore-induced plant volatiles (HIPVs) produced following H. cunea feeding. Notably, M. alba was the sole plant species that did not emit tridecane. These results suggest that H. cunea utilizes M. alba as a reduced predation enemy-free space, thereby minimizing parasitization by C. cunea. Our research emphasizes the importance of considering adaptive responses of herbivores within the context of multi-trophic relationships, rather than solely focusing on optimizing herbivore growth on the most nutritionally suitable plant host. Full article

Restricting the use of chemical pesticides in forestry requires the search for alternative solutions. These could be volatile organic compounds produced by three investigated species of bacteria (Bacillus amyloliquefaciens (ex Fukumoto) Priest, B. subtilis (Ehrenberg) Cohn and B. thuringiensis Berliner), which inhibit the growth of the pathogen F. oxysporum Schltdl. emend. Snyder & Hansen in forest nurseries. The highest inhibition of fungal growth (70%) was observed with B. amyloliquefaciens after 24 h of antagonism test, which had a higher content of carbonyl compounds (46.83 ± 8.41%) than B. subtilis (41.50 ± 6.45%) or B. thuringiensis (34.62 ± 4.77%). Only in the volatile emissions of B. amyloliquefaciens were 3-hydroxybutan-2-one, undecan-2-one, dodecan-5-one and tetradecan-5-one found. In contrast, the main components of the volatile emissions of F. oxysporum were chlorinated derivatives of benzaldehyde (e.g., 3,5-dichloro-4-methoxybenzaldehyde) and chlorinated derivatives of benzene (e.g., 1,4-dichloro-2,5-dimethoxybenzene), as well as carbonyl compounds (e.g., benzaldehyde) and alcohols (e.g., benzyl alcohol). Further compounds were found in the interactions between B. amyloliquefaciens and F. oxysporum (e.g., $\alpha$-cubebene, linalool, undecan-2-ol, decan-2-one and 2,6-dichloroanisole). Specific substances were found for B. amyloliquefaciens (limonene, nonan-2-ol, phenethyl alcohol, heptan-2-one and tridecan-2-one) and for F. oxysporum (propan-1-ol, propan-2-ol, heptan-2-one and tridecan-2-one). The amounts of volatile chemical compounds found in B. amyloliquefaciens or in the bacterium–fungus interaction can be used for further research to limit the pathogenic fungus. In the future, one should focus on the compounds that were found exclusively in interactions and whose content was higher than in isolated bacteria. In order to conquer an ecological niche, bacteria increase the production of secondary metabolites, including specific chemical compounds. The results presented are a prerequisite for creating an alternative solution or supplementing the currently used methods of plant protection against F. oxysporum. Understanding and applying the volatile organic compounds produced by bacteria can complement chemical plant protection against the pathogen, especially in greenhouses or tunnels where plants grow in conditions that favour fungal growth. Full article

In this study, we analysed cocoa (a dried and fully fermented seed of Theobroma cacao L.) from two Amazonian cultivars and a commercial sample of the Amazonian variety EETP801, grown under sustainable organic conditions, in comparison to CCN51 cocoa grown on a neighbouring commercial farm using standard practises and a European commercial cacao powdered beverage. The overall metabolite profile of the 70% aq acetone sample cocoa extracts was analysed using high-performance TLC analyses (HPTLC), and the xanthine alkaloids were analysed using quantitative liquid chromatography–UV photodiode array (HPLC-DAD) analyses. The volatile fraction in the headspace of the freshly ground cocoa was subjected to solid phase micro-extraction and analysed by gas chromatography–mass spectrometry (HS-SPME/GC-MS). Total polyphenol content was determined by the Folin–Ciocalteu method. Despite the reduced production of cocoa by the EETP801 cultivar in comparison with the CCN51 cultivar, the obtained produce is significantly richer in theobromine (130 mg vs. 170 mg per g of cacao), with CCN51 having a double concentration of theophylline (12.6 vs. 6.5 mg per g of cacao). Qualitatively, the two Amazonian cocoa samples had a similar polyphenolic composition (per the HPTLC fingerprint). HS-SPME/GC-MS analyses revealed that all the samples show a spontaneous emission profile mainly rich in non-terpene derivatives, of which hydrocarbons and pyrazines are the most abundant groups. The most represented volatile organic compound is n-tridecane for both EETP801 and CCN51. The variability in the artisan fermentation and roasting processes influenced certain aspects of the volatile composition as reflected by the trimethyl pyrazine/tetramethyl pyrazine ratio, which was zero in EETP-801 and lower than 1 in CCN51. Acetic acid was absent in CCN51 but significant (c.a. 5.5.%) in EETP801 and the commercial samples. The cultivar EETP801 is a viable option for a more ecologically conscious sector of the cocoa beverages consumer group. Full article

Due to the complexity of planning and constructing underground lines, construction challenges—such as close proximity and multi-line interactions—are increasingly being recognized, along with their associated safety hazards. The visual observation of tunnel deformation and changes in the surrounding strata is difficult. In this study, laboratory model experiments were conducted using a mixture of liquid paraffin, n-tridecane, and silica gel powder, combined in specific proportions to create a transparent material that simulates natural soft rock. The new tunnel was designed to simultaneously cross over and under two existing tunnels. The impact of the new tunnel on the existing tunnels was examined, with excavation length and soil layer thickness considered as the primary influencing factors. The results indicate that excavating the new tunnel causes settlement deformation in the tunnels above and heave deformation in the tunnels below. The magnitude of deformation increases as excavation progresses but decreases with the greater thickness of the soil interlayer. For an existing tunnel, variations in the thickness of the soil interlayer not only affect its own deformation but also disturb the tunnel on the opposite side. Therefore, to ensure safer and orderly urban tunnel construction and to address the “black box” effect, it is essential to study the deformation characteristics of existing tunnels and their surrounding rock during the construction of new tunnels. Full article

The Carabidae family, or ground beetles, is a wide and ecologically significant group within the Coleoptera order, known for its role as natural predators of agricultural pests and as bioindicators of ecosystem health. These beetles employ a variety of behavioral, morphological, and chemical defense strategies to protect themselves from predators. These mechanisms include gregariousness, stridulation, regurgitation, and chemical defenses, such as the secretion of irritating compounds from specialized glands. The defensive strategies of carabids are classified into passive and active systems, each with varying energetic costs. Chemical substances (e.g., Formic acid, Methacrylic acid, Tiglic acid, Ethacrilic acid, Isovaleric acid, Salicylaldehyde, 1,4-Benzoquinone, Toluquinone, 13-2Kt tridecan-2-one, Undecane, Tridecane, Pentadecane, M-cresol) are particularly important, as they serve to deter predators and combat pathogens like bacteria and fungi. Ground beetles utilize both polar and non-polar compounds in their defense, all contributing to their ecological success. This review explores the array of defensive mechanisms in the Carabidae family, highlighting experimental studies, field observations, and reviews published over the last five decades. The aim is to provide a comprehensive understanding of how these strategies enhance the survival and fitness of carabid beetles in their natural environments. Full article

The lubrication performance of the cylinder liner–piston ring (CLPR) is crucial for the energy efficiency and operating reliability of marine diesel engines. To enhance the boundary lubrication of marine engine oil, a 1,3-diketone fluid HPTD (1-(4-hexylphenyl) tridecane-1,3-dione, HPTD) was introduced as an ash-free friction modifier. Besides that, octadecylamine-functionalized nanocopper particles (ODA-Cu) were also added to the marine oil to improve its anti-wear behavior. Through cylinder-on-disk friction tests, the appropriate contents of HPTD and ODA-Cu were determined, which then formed hybrid additives and modified the engine oil. The tribological performance of the modified oil was analyzed under various normal loads, reciprocating frequencies, and testing temperatures. Based on the synergy of the tribochemical reaction of HPTD and the mending effect of ODA-Cu on the sliding surface, the modified oil not only had lower sulfated ash content but also exhibited superior lubrication performance (i.e., reduced coefficient of friction by 15%, smaller wear track by 43%, and higher maximum non-seizure load by 11%) than the pristine engine oil. The results of this study would be helpful for the design of novel hybrid eco-friendly additives for marine engine oil. Full article

The present study is the first report on the chemical and enantiomeric compositions of essential oils from the Ecuadorian species Gynoxys hallii Hieron., Gynoxys calyculisolvens Hieron., and Gynoxys azuayensis Cuatrec. All the volatile fractions presented a sesquiterpene-based chemical profile, typical of other volatile fractions from this genus. Both qualitative (GC-MS) and quantitative (GC-FID) chemical analyses were carried out on two stationary phases of different polarity (non-polar and polar). The main constituents of G. hallii essential oil on the two columns, respectively, were α-pinene (33.6–31.5%), (E)-β-caryophyllene (6.2–6.4%), germacrene D (35.7–38.3%), and bicyclogermacrene (3.8–4.0%). In G. calyculisolvens, the major compounds were α-pinene (11.2–11.0%), p-cymene (4.0–3.7%), α-copaene (3.6–3.7%), (E)-β-caryophyllene (8.1–8.3%), germacrene D (20.8–22.0%), and germacrene D-4-ol (8.4–8.6%). Finally, the main components of G. azuayensis were α-pinene (4.5–4.1%), germacrene D (14.1–12.4%), bicyclogermacrene (2.6–3.0%), tridecanal (6.4–6.2%), and spathulenol (7.8–7.1%). Furthermore, enantioselective analyses were conducted on the three volatile fractions, using two stationary phases based on β-cyclodextrins. As a result, twelve chiral components were investigated, detecting both enantiomerically pure compounds and scalemic mixtures with various enantiomeric excess. Full article

Background/Objectives: Biogenic volatile organic compounds (BVOCs), extensively studied in terrestrial plants with global emissions around 1 PgC yr⁻¹, are also produced by marine organisms. However, benthic species, especially seagrasses, are understudied despite their global distribution (177,000–600,000 km²). This study aims to examine BVOC emissions from key Mediterranean seagrass species (Cymodocea nodosa, Posidonia oceanica, Zostera noltei, and Zostera marina) in marine and coastal lagoon environments. Methods: BVOCs were collected using headspace solid-phase microextraction (HS-SPME) using divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fibers and analyzed by gas chromatography–mass spectrometry (GC-MS). Results: An important chemical diversity was found with a total of 92 volatile compounds (61 for Z. noltei, 59 for C. nodosa, 55 for P. oceanica, and 51 for Z. marina), from different biosynthetic pathways (e.g., terpenoids, benzenoids, and fatty acid derivatives) and with several types of chemical functions (e.g., alkanes, esters, aldehydes, and ketones) or heteroatoms (e.g., sulfur). No differences in chemical richness or diversity of compounds were observed between species. The four species shared 29 compounds enabling us to establish a specific chemical footprint for Mediterranean marine plants, including compounds like benzaldehyde, benzeneacetaldehyde, 8-heptadecene, heneicosane, heptadecane, nonadecane, octadecane, pentadecane, tetradecane, and tridecanal. PLS-DA and Heatmap show that the four species presented significantly different chemical profiles. The major compounds per species in relative abundance were isopropyl myristate for C. nodosa (25.6%), DMS for P. oceanica (39.3%), pentadecane for Z. marina (42.9%), and heptadecane for Z. noltei (46%). Conclusions: These results highlight the potential of BVOCs’ emission from seagrass ecosystems and reveal species-specific chemical markers. Full article

Codonopsis convolvulacea is a highly valued Chinese medicinal plant containing diverse bioactive compounds. While roots/tubers have been the main medicinal parts used in practice, leaves and stems may also harbor valuable phytochemicals. However, research comparing volatiles across tissues is lacking. This study performed metabolomic profiling of leaves, stems, and tubers of C. convolvulacea to elucidate tissue-specific accumulation patterns of volatile metabolites. Ultra-high performance liquid chromatography–tandem mass spectrometry identified 302 compounds, belonging to 14 classes. Multivariate analysis clearly differentiated the metabolic profiles of the three tissues. Numerous differentially accumulated metabolites (DAMs) were detected, especially terpenoids and esters. The leaves contained more terpenoids, ester, and alcohol. The stems accumulated higher levels of terpenoids, heterocyclics, and alkaloids with pharmaceutical potential. The tubers were enriched with carbohydrates like sugars and starch, befitting their storage role, but still retained reasonable amounts of valuable volatiles. The characterization of tissue-specific metabolic signatures provides a foundation for the selective utilization of C. convolvulacea parts. Key metabolites identified include niacinamide, p-cymene, tridecanal, benzeneacetic acid, benzene, and carveol. Leaves, stems, and tubers could be targeted for antioxidants, drug development, and tonics/nutraceuticals, respectively. The metabolomic insights can also guide breeding strategies to enhance the bioactive compound content in specific tissues. This study demonstrates the value of tissue-specific metabolite profiling for informing the phytochemical exploitation and genetic improvement of medicinal plants. Full article

In response to the escalating demand for sustainable agricultural methodologies, the utilization of microbial volatile organic compounds (VOCs) as antagonists against phytopathogens has emerged as a viable eco-friendly alternative. Microbial volatiles exhibit rapid diffusion rates, facilitating prompt chemical interactions. Moreover, microorganisms possess the capacity to emit volatiles constitutively, as well as in response to biological interactions and environmental stimuli. In addition to volatile compounds, these bacteria demonstrate the ability to produce soluble metabolites with antifungal properties, such as APE Vf, pyoverdin, and fragin. In this study, we identified two Pseudomonas strains (BJa3 and MCal1) capable of inhibiting the in vitro mycelial growth of the phytopathogenic fungus Aspergillus flavus, which serves as the causal agent of diseases in sugarcane and maize. Utilizing GC/MS analysis, we detected 47 distinct VOCs which were produced by these bacterial strains. Notably, certain volatile compounds, including 1-heptoxydecane and tridecan-2-one, emerged as primary candidates for inhibiting fungal growth. These compounds belong to essential chemical classes previously documented for their antifungal activity, while others represent novel molecules. Furthermore, examination via confocal microscopy unveiled significant morphological alterations, particularly in the cell wall, of mycelia exposed to VOCs emitted by both Pseudomonas species. These findings underscore the potential of the identified BJa3 and MCal1 Pseudomonas strains as promising agents for fungal biocontrol in agricultural crops. Full article

Sol g 2 is the major protein in Solenopsis geminata fire ant venom. It shares the highest sequence identity with Sol i 2 (S. invicta) and shares high structural homology with LmaPBP (pheromone-binding protein (PBP) from the cockroach Leucophaea maderae). We examined the specific Sol g 2 protein ligands from fire ant venom. The results revealed that the protein naturally formed complexes with hydrocarbons, including decane, undecane, dodecane, and tridecane, in aqueous venom solutions. Decane showed the highest affinity binding (K_d) with the recombinant Sol g 2.1 protein (rSol g 2.1). Surprisingly, the mixture of alkanes exhibited a higher binding affinity with the rSol g 2.1 protein compared to a single one, which is related to molecular docking simulations, revealing allosteric binding sites in the Sol g 2.1 protein model. In the trail-following bioassay, we observed that a mixture of the protein sol g 2.1 and hydrocarbons elicited S. geminata worker ants to follow trails for a longer time and distance compared to a mixture containing only hydrocarbons. This suggests that Sol g 2.1 protein may delay the evaporation of the hydrocarbons. Interestingly, the piperidine alkaloids extracted have the highest attraction to the ants. Therefore, the mixture of hydrocarbons and piperidines had a synergistic effect on the trail-following of ants when both were added to the protein. Full article

In this study, we developed a thermal storage medium comprising porous activated carbon filled with organic phase-change materials (PCMs) that utilizes the latent heat of phase-change to absorb heat during heating and release heat during cooling. For the activated carbon, we used both charcoal-based powdered activated carbon (250–350 mesh) and granular activated carbon. The organic phase-change materials used in the experiments were dodecane, tridecane, tetradecane, and pentadecane. Material properties such as thermal conductivity, latent heat, and melting temperature range were evaluated experimentally and theoretically, with the results observed to be consistent. The cyclic thermal performance of the proposed medium was also evaluated. Notably, filling the activated carbon with a mixture of organic PCMs resulted in the highest temperature-moderating effect. The procedure and results presented in this study are expected to aid in further improvement in the performance of thermal storage media containing PCM where stable temperatures are required, including building heating and cooling. Full article

Albertia edulis is known as Puruí, and its leaf tea is used in the hypoglycemic and antihypertensive treatments of the Amazon native population. This study aimed to evaluate the phytochemical composition and antioxidant properties of the Puruí pulp fruit. The hydroethanolic (LFP-E), ethyl acetate (LFP-A), and volatile concentrate (LPF-V) extracts of Puruí lyophilized fruit pulp were analyzed via LC-ISI-IT-MS, GC, and GC-MS. Moreover, total phenolic and flavonoid content (TPC and TFC) and TEAC/ABTS and DPPH assays were conducted to determine their antioxidant capacity. Compounds palmitic acid, methyl linolenate, methyl linoleate, palmitic alcohol, benzene acetaldehyde, tridecanal, and furfural were mainly identified in the LPF-V extract. Compounds caffeic and quinic acids, genipin, annonaine, 3′-7-dimethoxy-3-hydroxyflavone, 4′-hydroxy-5,7-dimethoxyflavone, 6-hydroxy-7-epigardoside methyl ester, baicalin, and phloretin-2-O-apiofuranosyl-glucopyranoside were mainly identified in the LFP-E and LFP-A extracts. For LFP-E and LFP-A extracts, TPC values were 5.75 ± 0.75 and 66.75 ± 3.1 mg GAE/g; TFC values were 1.14 ± 0.65 and 50.97 ± 1.2 mg QE/g; DPPH assay showed EC₅₀ values of 1021.65 ± 5.9 and 133.60 ± 3.9 µg/mL; and TEAC/ABTS assay showed values of 28.36 ± 3.7 and 142.26 ± 2.2 µM TE/g. Alibertia edulis fruits are significant sources of phenolic compounds, also showing significant antioxidant capacity. The Puruí fruit seems promising for developing innovative and healthy products for the nutritional food market. Full article

Rice (Oryza sativa L.) is an important food crop in Taiwan, among which fragrant rice is highly regarded for its special aroma when cooked. During the storage of fragrant rice, the aroma components will change, which will affect the aroma quality of fragrant rice. Therefore, headspace solid-phase microextraction (HS-SPME) was used in this study, combined with gas chromatography and gas chromatography-mass spectrometry, to analyze the difference in the aroma components of Taikeng No. 4 (TK4), Tainung No. 71 (TN71), Kaohsiung No. 147 (KH147), and Taichung No. 194 (TC194) fragrant rice. A total of 28 aroma components were identified in the four varieties of fragrant rice, and the main components were all Nonanal. Among them, TK4 contains a very high content of hydrocarbons, including Tridecane and Dodecane; TN71, KH147, and TC194 contain mainly aldehydes such as Nonanal and Hexanal. During different storage times, the contents of alcohols, monoterpenes, aromatic aldehydes, and furans increased with storage time, while the content of aliphatic aldehydes decreased with storage time. After storage, the fragrant rice samples showed a tendency for the total volatile component content to decrease, with the most pronounced reduction observed in Nonanal content. Full article

The human body releases numerous volatile organic compounds (VOCs) through tissues and various body fluids, including breath. These compounds form a specific chemical profile that may be used to detect the colorectal cancer CRC-related changes in human metabolism and thereby diagnose this type of cancer. The main goal of this study was to investigate the volatile signatures formed by VOCs released from the CRC tissue. For this purpose, headspace solid-phase microextraction gas chromatography-mass spectrometry was applied. In total, 163 compounds were detected. Both cancerous and non-cancerous tissues emitted 138 common VOCs. Ten volatiles (2-butanone; dodecane; benzaldehyde; pyridine; octane; 2-pentanone; toluene; p-xylene; n-pentane; 2-methyl-2-propanol) occurred in at least 90% of both types of samples; 1-propanol in cancer tissue (86% in normal one), acetone in normal tissue (82% in cancer one). Four compounds (1-propanol, pyridine, isoprene, methyl thiolacetate) were found to have increased emissions from cancer tissue, whereas eleven showed reduced release from this type of tissue (2-butanone; 2-pentanone; 2-methyl-2-propanol; ethyl acetate; 3-methyl-1-butanol; d-limonene; tetradecane; dodecanal; tridecane; 2-ethyl-1-hexanol; cyclohexanone). The outcomes of this study provide evidence that the VOCs signature of the CRC tissue is altered by the CRC. The volatile constituents of this distinct signature can be emitted through exhalation and serve as potential biomarkers for identifying the presence of CRC. Reliable identification of the VOCs associated with CRC is essential to guide and tune the development of advanced sensor technologies that can effectively and sensitively detect and quantify these markers. Full article