Yeasts interface insect herbivores with their food plants. Communication depends on volatile metabolites, and decoding this chemical dialogue is key to understanding the ecology of insect-yeast interactions. This study explores the volatomes of eight yeast species which have been isolated from foliage, from flowers or fruit, and from plant-feeding insects. These yeasts each release a rich bouquet of volatile metabolites, including a suite of known insect attractants from plant and floral scent. This overlap underlines the phylogenetic dimension of insect-yeast associations, which according to the fossil record long predate the appearance of flowering plants. Volatome composition is characteristic for each species, aligns with yeast taxonomy, and is further reflected by a differential behavioral response of cotton leafworm larvae, which naturally feed on foliage of a wide spectrum of broad-leaved plants. Larval discrimination may establish and maintain associations with yeasts and is also a substrate for designing sustainable insect management techniques.

Vanillin is an aromatic aldehyde found as a component of lignocellulosic material, and in the cured pods of orchidaceae plants. Like other phenolic substances, vanillin has antimicrobial activity and can be extracted from lignin either by a thermo-chemical process or through microbial degradation. Vanillin, can serve as a model monomer in biodegradation studies of lignin. In the present study, a yeast isolated from decaying wood on the Faroe Islands, was identified as Cystobasidium laryngis strain FMYD002, based on internal transcribed spacer sequence analysis. It demonstrated the ability to convert vanillin to vanillyl alcohol, as detected by ultra-high performance liquid chromatography–quadrupole-time-of-flight. Structural analysis of vanillyl alcohol was carried out by using gas chromatography–mass spectrometry and 1H NMR spectroscopy, and further verified by synthesis. The reduction of vanillin to vanillyl alcohol has been documented for only a few species of fungi. However, to our knowledge, this biotransformation has not yet been reported for basidiomycetous yeast species, nor for any representative of the subphylum Pucciniomycotina. The biotransformation capability of the present strain might prove useful in the industrial utilisation of lignocellulosic residues.Electronic supplementary materialThe online version of this article (10.1186/s13568-018-0666-4) contains supplementary material, which is available to authorized users.

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Yeasts form mutualistic interactions with insects. Hallmarks of this 24 interaction include provision of essential nutrients, while insects facilitate yeast 25 dispersal and growth on plant substrates. A phylogenetically ancient, chemical 26 dialogue coordinates this interaction, where the vocabulary, the volatile chemicals 27 that mediate the insect response, remains largely unknown. Here, we employed gas 28 chromatography-mass spectrometry (GC-MS), followed by hierarchical cluster 29 (HCA) and orthogonal partial least square discriminant analysis (OPLS-DA), to 30 profile the volatomes of six Metschnikowia spp., Cryptococcus nemorosus and 31 brewer's yeast Saccharomyces cerevisiae. The yeasts, which are all found in 32 association with insects feeding on foliage or fruit, emit characteristic, species-33 specific volatile blends that reflect the phylogenetic context. Species-specificity of 34 these volatome profiles aligned with differential feeding of cotton leafworm larvae 35 Spodoptera littoralis on these yeasts. Bioactivity correlates with yeast ecology; 36 phylloplane species elicited a stronger response than fruit yeasts, and larval 37 discrimination may provide a mechanism for establishment of insect-yeast 38 associations. The yeast volatomes contained a suite of insect attractants known from 39 plant and especially floral headspace, including (Z)-hexenyl acetate, ethyl (2E,4Z)-40 deca-2,4-dienoate (pear ester), (3E)-4,8-dimethylnona-1,3,7-triene (DMNT), linalool, 41 α-terpineol, β-myrcene or (E,E)-a-farnesene. A wide overlap of yeast and plant 42 volatiles, notably floral scents further emphasizes the prominent role of yeasts in 43 plant-microbe-insect relationships including pollination. The knowledge of insect-44 Ljunggren et al. -p. 3 yeast interactions can be readily brought to practical application, live yeasts or yeast 45 metabolites mediating insect attraction provide an ample toolbox for the 46 development of sustainable insect management. 47 IMPORTANCE Yeasts interface insect herbivores with their food plants. 48 Communication depends on volatile metabolites, and decoding this chemical 49 dialogue is key to understanding the ecology of insect-yeast interactions. This study 50 explores the volatomes of eight yeast species which have been isolated from foliage, 51 flowers or fruit, and from plant-feeding insects. They each release a rich bouquet of 52 volatile metabolites, including a suite of known insect attractants from plant and 53 floral scent. This overlap underlines the phylogenetic dimension of insect-yeast 54 associations, which according to the fossil record, long predate the appearance of 55 flowering plants. Volatome composition is characteristic for each species, aligns with 56 yeast taxonomy, and is further reflected by a differential behavioural response of 57 cotton leafworm larvae, which naturally feed on foliage of a wide spectrum of broad-58 leaved plants. Larval discrimination may establish and maintain associations with 59 yeasts and is also a substrate for designing sustainabl...

Hedenström | (2020) Appropriate technology for soil remediation in tropical low-income countries -a pilot scale test of three different amendments for accelerated biodegradation of diesel fuel in Ultisol, Cogent

Synthetic and heavy metal antifungals are frequently used as wood preservatives. However, they exhibit relatively inert biodegradation and toxic properties when leached; this makes their replacement with environmentally degradable yet functional alternatives a key target in the wood protection industry. In this context, distilled fractions of raw thermomechanical pulp turpentine (TMP-T) from Picea abies were assessed for their wood protecting capabilities against wood-decaying fungi. Antifungal bioactivity of fractions and some of their combinations were screened on agar-plates against the brown-rot fungus Coniophora puteana. Addition of TMP-T fractions showed a significant fungal growth rate reduction, while mixtures indicated the presence of synergistic and antagonistic effects. One fraction, obtained after distilling 1 L TMP-T at 111-177 °C at 0.5 mbar, showed complete growth inhibition of Antrodia sinuosa, Serpula lacrymans, Serpula himantioides and significant inhibition of Antrodia serialis, Antrodia xantha, Gloeophyllum sepiarium, Heterobasidion parviporum at a concentration of 1000 ppm. This fraction was further examined for long-and medium-term effects on wood decay in microcosm soiljar and field experiment, respectively. The known antifungal compounds benzisothiazolinone, 2-octyl-4-isothiazolin-3-one, 3-iodo-2-propynyl N-butylcarbamate and two commercial wood preservatives were used as reference treatments. Commercial preservatives instilled long-term efficacy against C. puteana wood decay in a soil-jar microcosm experiment, but no noticeable protection with antifungal compounds or the present treatments was found. However, a moderate effect by the TMP-T fraction from the in vitro assay was observed and the TMP-turpentine distillation residue showed a similar fungal inhibition effect to the most potent commercial treatment after 29 months in the field.

Metal-semiconductor junctions and interfaces have been studied for many years due to their importance in applications such as semiconductor electronics and solar cells. However, semiconductor-metal networks are less studied because there is a lack of effective methods to fabricate such structures. Here, we report a novel Au–ZnO-based metal-semiconductor (M-S)n network in which ZnO nanowires were grown horizontally on gold particles and extended to reach the neighboring particles, forming an (M-S)n network. The (M-S)n network was further used as a gas sensor for sensing ethanol and acetone gases. The results show that the (M-S)n network is sensitive to ethanol (28.1 ppm) and acetone (22.3 ppm) gases and has the capacity to recognize the two gases based on differences in the saturation time. This study provides a method for producing a new type of metal-semiconductor network structure and demonstrates its application in gas sensing.