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Biogeneration of Volatile Organic Compounds in Microalgae-Based Systems
Published in Gokare A. Ravishankar, Ranga Rao Ambati, Handbook of Algal Technologies and Phytochemicals, 2019
Pricila Nass Pinheiro, Karem Rodrigues Vieira, Andriéli Borges Santos, Eduardo Jacob-Lopes, Leila Queiroz Zepka
Geosmin and 2-methylisoborneol (2-MIB) are synthesized through the isoprenoid pathways, isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMADP), and are the central intermediates in the isoprenoid biosynthesis. They can be produced in the mevalonate pathway (MVA) or methylerythritol phosphate (MEP) pathway. Subsequently these starter molecules are converted to immediate prenyl diphosphate precursors, such as geranyl diphosphate (GDP) and farnesyl diphosphate (FDP) (Liato and Aïder 2017; Meena et al. 2017). The cyclization of farnesyl diphosphate (FDP) to geosmin is catalyzed by geosmin synthase via three steps (farnesyl diphosphate to germacradienol, germacradienol to 8,10-dimethyl-1-octalin, and 8,10-dimethyl-1-octalin to geosmin) in cyanobacteria (Giglio et al. 2008). The 2-MIB synthase mechanism is based 2-C-methyltransferase catalyzed methylation of geranyl diphosphate, C10 monoterpene precursor, into 2-methylgeranyl diphosphate. Then, 2-MIB synthase catalyzes cyclization of the 2-methylgeranyl diphosphate to 2-MIB (Lee et al. 2017).
Characterizing Outdoor Air Using Microbial Volatile Organic Compounds (MVOCs)
Published in Raquel Cumeras, Xavier Correig, Volatile organic compound analysis in biomedical diagnosis applications, 2018
Sonia Garcia-Alcega, Frédéric Coulon
Apart from this, researchers do not analyze and report same MVOCs (García-Alcega et al., 2016), and MVOC contaminant concentration threshold and concentration limits are not consistent. For example, in a study of indoor air from buildings, Lorenz et al. (2002) identified the MVOCs 1-octen-3-ol, dimethyl disulfide and 3-methylfuran as the main indicators of microbial growth. The authors determined that there is an indoor microbial source of contamination when the detection of one of these MVOCs is present at concentrations above 50 ng m–3 or when the sum of eight MVOCs (1-octen-3-ol, 3-methylfurane, dimethyl disulfide, 3-methyl-1-butanol, 2-pentanol, 2-hexanone, 2-heptanone, 3-octanone) together with at least one of the 3 main MVOCs indicators of microbial growth equals or exceeds 500 ng m–3. Opposite to this, Korpi et al. (2009) suggested other limits for 3-methylfurane (≥ 200) and 1-octene-3-ol and 3-methyl-1-butanol ≥ 10000 ng m–3. This author also listed another MVOCs different from the ones reported by Lorenz et al. (geosmin ≥ 50, 2-isopropyl-3- methoxypyrazine ≥ 400, 2-methyl1-propanol and 2-methylisoborneol ≥ 1500, 2-octen-1-ol ≥ 15000 ng m–3).
Hazards associated with the microbiological contamination of cosmetics, toiletries and non-sterile pharmaceuticals
Published in R. M. Baird, S. F. Bloomfield, Microbial quality assurance in cosmetics, toiletries and non-sterile Pharmaceuticals, 2017
A variety of aroma-producing bacteria have long been identified (Omelianski 1923). Often their unpleasant odours are combined in spoiled products and are particularly disastrous in cosmetics and toiletries which depend so much on their own specific perfumes. Geosmin, a strongly earth-smelling neutral oil, is produced by some actinomycetes (Gerber and Lechevalier 1965) but the aromatic elements responsible for the typical smell of mould do not appear to have been identified. An alcoholic odour obviously indicates spoilage by yeast.
Metabolic and pharmacological profiling of Penicillium claviforme by a combination of experimental and bioinformatic approaches
Published in Annals of Medicine, 2022
Zafar Ali Shah, Khalid Khan, Zafar Iqbal, Tariq Masood, Hassan A. Hemeg, Abdur Rauf
Although the existence of geosmin was mentioned in the literature, it was not detected in our study. However, the presence of its precursor farnesyl was confirmed in this study [56,57]. According to the published literature, the production of metabolites in fungi depends on various factors such as nutrients and temperature [58].
A short guide to insect oviposition: when, where and how to lay an egg
Published in Journal of Neurogenetics, 2019
Kevin M. Cury, Benjamin Prud’homme, Nicolas Gompel
This model has been tested in D. melanogaster. Like most Drosophila species, D. melanogaster has a special relationship with fermenting or rotten substrates, in particular fruits. Flies are attracted by fruit odors and their olfactory system is tuned to the scent of the various metabolic compounds produced by the microorganisms growing on fruits, many of which mimic the scent of fruits (Mansourian & Stensmyr, 2015 for review). Some of these odors also modulate oviposition behavior, positively or negatively, through dedicated olfactory sensory receptors and neurons. Ethanol and acetic acid, produced during the fermentation process, elicit egg laying (Adolph, 1920; Chen & Amrein, 2017; Joseph, Devineni, King, & Heberlein, 2009). In addition, oviposition is stimulated by the leaf odor E2-hexenal, detected by Or7a (Lin, Prokop-Prigge, Preti, & Potter, 2015); by the volatile terpenes limonene and valencene, abundant in fruit of the Citrus family, detected by Or19a (Dweck et al., 2013); and by ethylphenols produced by yeast growing on fruit, detected by Or71a (Dweck et al., 2015). Of note, most of these oviposition-stimulating odors are otherwise not particularly attractive to females, suggesting instead that they specifically elicit oviposition when females are on, or very close to, the fruit. In parallel, females also detect olfactory cues that inhibit oviposition and which are produced by various threats that are common at or around oviposition sites. These deterrent odors include geosmin emanating from toxic molds, detected by Or56a (Stensmyr et al., 2012); phenol produced by pathogenic bacteria, detected by Or46a (Mansourian et al., 2016); and pheromones of parasitoid wasps, detected by Or49a (Ebrahim et al., 2015). The activation of the olfactory sensory neurons expressing each of these receptors is sufficient to evoke, or inhibit, oviposition behavior, suggesting that these neurons and the odors they detect play key roles in the decision to lay an egg on a particular substrate. Most of the ORs involved in oviposition behavior are narrowly tuned (except Or7A, see below), and the olfactory sensory neurons expressing these receptors appear to be part of neural circuits that are dedicated to specific functions associated with egg-laying behavior. The specialization of these neural circuits to particular compounds contrasts with the combinatorial coding that is usually required to process odors. This uncommon situation could result from the strong ecological relevance of the signals detected by these circuits (Haverkamp, Hansson, & Knaden, 2018).