Environmental context of endophyte symbioses: Interacting effects of water stress and insect herbivory

Symbiotic associations between grasses and fungal endophytes are generally regarded as mutualistic, yet benefits to host plants may vary with environmental context. Previous studies have emphasized how endophytes influence plant responses to single stressors. In contrast, the outcome of endophyte-grass interactions under simultaneous biotic and abiotic stresses remains poorly explored. We hypothesized that benefits from endophyte symbiosis become most apparent in "complex" environments where hosts experience multiple stresses. We evaluated the performance of endophyte-infected (E+) vs. endophyte-uninfected (E-) Lolium multiflorum plants in a factorial experiment with water supply (control vs. drought) and insect herbivory (with aphids vs. without aphids). Endophyte infection delayed tiller production in well-watered plants, while water stress reduced tillering in E- plants. Endophyte mediation of herbivory tolerance was contingent on water supply. Whereas aphid herbivory was detrimental to E+ plants in well-watered soils, aphids interacted with drought stress in decreasing the reproductive output of E- but not E+ plants. Moreover, endophyte presence decreased aphid densities on drought-stressed plants only. Thus, endophyte symbiosis enhanced host tolerance to overlapping biotic and abiotic stresses, although infected plants failed to outgrow their uninfected counterparts. These results support the view that mutualistic endophyte effects may not arise in low-stress environments. © 2011 by The University of Chicago. All rights reserved.Fil: Miranda, M. Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Omacini, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Chaneton, Enrique Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentin

Microbial valorization of waste cooking oils for valuable compounds production a review

Waste cooking oils (WCO) are vegetable oils discarded after food frying and great amounts are produced worldwide. Its management is a challenge, due to the environmental risk of illegally disposal into rivers and landfills. The main approaches for WCO valorization included their incorporation as component of animal feed and biodiesel manufacturing. Yet, the development of new feasible approaches is attractive from an economic and ecological standpoint. Due to their composition in triglycerides, untreated WCO can be used as feedstock for microbial growth (several species are able to use them as carbon source) and production of added-value compounds. In this way, microbial valorization of WCO is a sustainable biotechnological approach to upgrade a waste into a renewable feedstock for bio-based industry, favoring the circular economy concept. The objective of this review is to highlight the potential use of WCO in bioprocesses as an alternative to other physicochemical treatments. Firstly, an introduction to WCO problematic is presented, describing most common applications used currently. Then, an extensive review on the use of WCO by microorganisms is shown, focusing on bacterial and fungi species and its exploitation for bioprocesses development to produce metabolites of industrial interest, such as biopolymers, biosurfactants, lipases and microbial lipids.This study was supported by the Portuguese Foundation for Science and Technology (FCT)under the scope of the project TUBITAK 2014 (TUBITAK/0009/2014), the strategic fund-ing of UID/BIO/04469/2019 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope ofNorte2020 - Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

Influence of Provenance, Subspecies, and Site on Wood Density in Eucalyptus Globulus Labill.

The wood density of Eucalyptus globulus was measured as basic density in 7-year-old trees from 37 provenances grown in three sites, on cores taken at breast height. The wood density was highly significantly influenced by provenance and very significantly by site. The across-site range of variation of wood density in the different provenances was between 486 kg/m3 and 430 kg/m3. The provenances of subspecies maidenii had a significantically higher density in relation to those from spp. globulus and bicostata (472 kg/m3 vs. 448 kg/m3 and 443 kg/m3). No correlation between growth and density was found

Biotechnological valorization of waste cooking oils: lipase and microbial lipids production by Yarrowia lipolytica

[Excerpt] Waste cooking oils (WCO) generated from vegetable oils used at high temperatures in food frying, cause environmental problems and must be reutilized. New strategies to valorize these wastes are attracting a great scientific interest due to the important advantages offered from an economic and environmental point of view. A microbial platform can be established to convert low-value hydrophobic substrates, such as waste cooking oils, to microbial lipids (single cell oil, SCO) and other value-added bioproducts, such as lipase. (...

Selection of yeast species for hydrocarbons and phenolic compounds degradation

[Excerpt] 1. Introduction. Large amounts of pollutant compounds are present in industrial effluents and, often, they are not totally degraded by physical and/or chemical methods before the discharge into the environment. Hydrocarbons and phenolic compounds are two examples of pollutants present in agro-industrial effluents, respectively in petroleum refinery effluents and olive mill wastewater (OMW). Biodegradation strategies involving microorganisms to simultaneously degrade these wastes and obtain high added-value products become an interesting approach, since the abundance of these compounds ensures the economic viability of bioprocesses while prevents major environmental problems. This work address the study of the ability of yeast species to grow on hydrocarbons and phenolic compounds as sole carbon and energy source. Moreover, the production of valuable compounds from these wastes was also assessed. [...]info:eu-repo/semantics/publishedVersio

Yarrowia lipolytica is a promising oleaginous yeast for bio-oils production from volatile fatty acids

Every year, approximately 931 million tons of food waste (FW) are generated worldwide. The discharge of FW in the landfill has a negative environmental impact due to water and soil pollution and GHG emission. Volatile fatty acids (VFAs), produced by anaerobic fermentation of FW, can be used as a substrate by oleaginous yeasts to produce bio-oils. The bioconversion of pure VFAs into Y. lipolytica biomass and bio-oils was affected by oxygenation conditions in batch cultures carried out in a stirred-tank bioreactor. Approximately 3-fold enhancement in lipids concentration was obtained by increasing the agitation and aeration rates. Two-stage batch cultures (1st stage growth in glucose; 2nd stage bio-oils production in VFAs) proved to be an effective approach to improve lipids accumulation from pure VFAs. The highest lipid content was attained in conditions of dissolved oxygen concentration of 45% of saturation during the lipogenic phase. Y. lipolytica also accumulated lipids in food waste-derived VFAs, particularly in two-stage batch cultures (1st stage growth in VFAs; 2nd stage bio-oils production in crude glycerol). These bio-oils are promising feedstock for the biodiesel industry and the estimated fuel properties of biodiesel are in accordance with international standards.info:eu-repo/semantics/publishedVersio

Dissolved oxygen effect on microbial lipids production by Yarrowia lipolytica from volatile fatty acids

Volatile fatty acids (VFAs) can be obtained from organic wastes through acidogenic fermentation and the yeast Yarrowia lipolytica can use those VFAs for the biosynthesis of lipids. Oxygen is an important factor of the bioconversion process of VFAs into microbial lipids by Y. lipolytica, thus the effect of oxygenation was evaluated in batch cultures of the yeast for two different strains, varying the stirring and air flow rates. The increase of dissolved oxygen concentration improved lipid production by Y. lipolytica W29 and Y. lipolytica NCYC 2904 in glucose and VFAs (acetate, propionate and butyrate) medium. The strain NCYC 2904 accumulated higher intracellular lipids (22%, w/w) than strain W29 (12%, w/w) with differences in lipids composition. Lipids of strain W29 were mainly composed by linoleic acid (up to 47%) and oleic acid (up to 31%) and NCYC 2904 accumulated predominantly oleic acid (around 56%). For both strains, the unsaturated fraction (> 70%) exceeded the saturated one. Since fatty acid composition in Y. lipolytica are similar to common vegetable oils (usually used for biodiesel production), these lipids are a potential feedstock for biofuels production.Projects TUBITAK/0009/2014; UID/BIO/04469/2019, grant SFRH/BD/129592/2017. BioTecNorte (NORTE-01-0145-FEDER000004).info:eu-repo/semantics/publishedVersio

Bioconversion of volatile fatty acids into microbial lipids by Yarrowia lipolytica

Volatile fatty acids (VFAs) are short chain fatty acids that can be obtained from organic wastes through acidogenic fermentation and can be used as carbon source for microbial lipids production. The bioconversion of acetate, propionate and butyrate into microbial lipids by Yarrowia lipolytica W29 was evaluated, and the yeast shown the ability to grow using VFA as carbon source and accumulate lipids intracellularly (around 5 % of dry cell mass). The addition of a co-substrate (glucose or glycerol) to VFA-based medium led to an enhancement of cellular growth and lipid content of the cells. The highest lipids concentration of around 1 g/L was obtained in batch cultures carried out with a mixture of VFAs and glycerol. Notwithstanding the low lipid content obtained in this work, Y. lipolytica demonstrated the ability to metabolize VFAs and convert them to microbial lipids, which can be used for biodiesel production.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the project TÜBITAK 2014 (TUBITAK/0009/2014) and of the strategic funding of UID/BIO/04469 unit and COMPETE 2020 (POCI-01-0145-FEDER006684), Post-Doctoral grant (SFRH/BPD/101034/2014), Doctoral grant (SFRH/BD/129592/2017) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

Yeast as a model organism for studying the evolution of non-standard genetic codes

During the last 30 years, a number of alterations to the standard genetic code have been uncovered both in prokaryotes and eukaryotic nuclear and mitochondrial genomes. But, the study of the evolutionary pathways and molecular mechanisms of codon identity redefinition has been largely ignored due to the assumption that non-standard genetic codes can only evolve through neutral evolutionary mechanisms and that they have no functional significance. The recent discovery of a genetic code change in the genus Candida that evolved through an ambiguous messenger RNA decoding mechanism is bringing that naive assumption to an abrupt end by showing, in a rather dramatic way, that genetic code changes have profound physiological and evolutionary consequences for the species that redefine codon identity. In this paper, the recent data on the evolution of the Candida genetic code are reviewed and an experimental framework based on forced evolution, molecular genetics and comparative and functional genomics methodologies is put forward for the study of non-standard genetic codes and genetic code ambiguity in general. Additionally, the importance of using Saccharomyces cerevisiae as a model organism for elucidating the evolutionary pathway of the Candida and other genetic code changes is emphasised.publishe

Remarks on the Vietoris sequence and corresponding convolution formulas

In this paper we consider the so-called Vietoris sequence, a sequence of rational numbers of the form ck=12k(k⌊k2⌋), k= 0, 1, ⋯. This sequence plays an important role in many applications and has received a lot of attention over the years. In this work we present the main properties of the Vietoris sequence, having in mind its role in the context of hypercomplex function theory. Properties and patterns of the convolution triangles associated with (ck)k are also presented.Research at CMAT was partially financed by Portuguese funds through FCT - Funda¸c˜ao para a Ciˆencia e a Tecnologia, within the Projects UIDB/00013/2020 and UIDP/00013/2020. Research at CIDMA has been financed by FCT, within the Projects UIDB/04106/2020 and UIDP/04106/2020