Atrazine-Induced Chlorosis in Synechococcus elongatus Cells

The effects of a widely used herbicide, atrazine, on the freshwater cyanobacterium Synechococcus elongatus were studied. The cyanobacteria were exposed to varying concentrations of atrazine (0.025, 0.05, 0.1, 0.25, and 0.75 µM) for 96 h. Different parameters such as growth, autofluorescence of chlorophyll a, pigment content, volume, and internal granularityof the cells were determined daily. Differences were detected between cultures with and cultures without atrazine for the parameters analyzed. Atrazine exposure induced the process of chlorosis in cyanobacterial cells, given that this herbicide has an effect on photosynthesis, chlorotic subpopulations having low values of chlorophyll a autofluorescence. More unpigmented subpopulations (chlorotic) appeared as the atrazine concentration increased and better growth rates resulted. Atrazine also induced changes in cell volume and internal granularity, these being most apparent after 48 h of exposure and in cultures with higher atrazine concentrations (0.25 and 0.75 µM).Xunta de Galicia; PGIDT01MAM10302P

Flow cytometric analysis of the encystment process induced by paraquat exposure in Haematococcus pluvialis (Chlorophyceae)

The freshwater microalga Haematococcus pluvialis exhibits a unique morphological response to environmental stress, accumulating carotenoid pigment during encystment. The complexity of characterizing the different cell stages and monitoring the pigment cell content during the life cycle of this microalga is one of the main problems reported when assessing astaxanthin accumulation and degradation. Therefore, with the aim of studying the potential encystment response in this microalga by means of flow cytometry (FCM), we induced oxidative stress in cultures of vegetative growing cells by treating them with paraquat, a known generator of superoxide anion radicals. Two flow cytometric approaches were successfully used to monitor the effect of oxidative stress on morphological changes and genesis of carotenoids in H. pluvialis: (1) a cytometric characterization of different cell types based on analysis of the fluorescence of chlorophyll a vs the fluorescence of astaxanthin, and (2) staining with the fluorochromes hydroethidium (HE) and dihydrorhodamine 123 (DHR), in order to measure the in vivo intracellular levels of reactive oxygen species (ROS). FCM data showed that astaxanthin accumulation during encystment hampers the production of ROS. Furthermore, the cell content of astaxanthin seems to be a good indicator of the extent to which H. pluvialis cells undergo oxidative stress, and also of how the cells defend themselves under stress conditions.Xunta de Galicia; INCITE08ENA103032E

Removal of triazine herbicides from freshwater systems using photosynthetic microorganisms

[Abstract]The uptake of the triazine herbicides, atrazine and terbutryn, was determined for two freshwater photosynthetic microorganisms, the green microalga Chlorella vulgaris and the cyanobacterium Synechococcus elongatus. An extremely rapid uptake of both pesticides was recorded, although uptake rate was lower for the cyanobacterium, mainly for atrazine. Other parameters related to the herbicide bioconcentration capacity of these microorganisms were also studied. Growth rate, biomass, and cell viability in cultures containing herbicide were clearly affected by herbicide uptake. Herbicide toxicity and microalgae sensitivity were used to determine the effectiveness of the bioconcentration process and the stability of herbicide removal. C. vulgaris showed higher bioconcentration capability for these two triazine herbicides than S. elongatus, especially with regard to terbutryn. This study supports the usefulness of such microorganisms, as a bioremediation technique in freshwater systems polluted with triazine herbicides.Xunta de Galicia; PGIDIT04RFO103946P

Physiological response of freshwater microalga (Chlorella vulgaris) to triazine and phenylurea herbicides

[Abstract]The effects of two herbicides used wide-spread, isoproturon (phenylurea) and terbutryn (triazine), on growth, dry weight, elemental composition, photosynthetic pigments and protein content, and cell volume assayed by flow cytometry in the freshwater microalgae Chlorella vulgaris were studied. Different parameters for algal activity show widely different sensitivities to these aquatic pollutants. After 96 h of herbicide exposure, terbutryn was the strongest inhibitor of growth, giving an EC50 value for growth twice lower than that for isoproturon cultures (EC50 terbutryn=0.097 μM; EC50 isoproturon=0.199 μM). However, lower concentrations of the triazine herbicide provoked an increase in the cellular density and growth rate of this microalga, not observed in the phenylurea-treated cultures. Cellular volume and dry weight of C. vulgaris cells were increased strongly in the presence of isoproturon and terbutryn. Other cellular parameters, such as pigment and protein content, were stimulated with both herbicides at higher concentrations.Xunta de Galicia; PGIDT01MAM10302P

Nutraceutical Potential of Phenolics from `Brava´ and `Mansa´ Extra-Virgin Olive Oils on the Inhibition of Enzymes Associated to Neurodegenerative Disorders in Comparison with Those of `Picual´ and `Cornicabra´

The increasing interest in theMediterranean diet is based on the protective effects against several diseases, including neurodegenerative disorders. Polyphenol-rich functional foods have been proposed to be unique supplementary and nutraceutical treatments for these disorders. Extra-virgin olive oils (EVOOs) obtained from 0Brava0 and 0Mansa0, varieties recently identified from Galicia (northwestern Spain), were selected for in vitro screening to evaluate their capacity to inhibit key enzymes involved in Alzheimer0s disease (AD) (acetylcholinesterase (AChE), butyrylcholinesterase (BuChE) and 5-lipoxygenase (5-LOX)), major depressive disorder (MDD) and Parkinson0s disease (PD) (monoamine oxidases: hMAO-A and hMAO-B respectively). 0Brava0 oil exhibited the best inhibitory activity against all enzymes, when they are compared to 0Mansa0 oil: BuChE (IC50 = 245 ± 5 and 591 ± 23 mg.mL-1), 5-LOX (IC50 = 45 ± 7 and 106±14 mg.mL-1), hMAO-A (IC50 = 30 ± 1 and 72 ± 10 mg.mL-1) and hMAO-B (IC50 = 191 ± 8 and 208 ±14 mg.mL-1), respectively. The inhibitory capacity of the phenolic extracts could be associated with the content of secoiridoids, lignans and phenolic acids.This work received financial support from Programa de Cooperación Interreg V-A España—Portugal (POCTEP) 2014–2020 (projects Ref.: 0181_NANOEATERS_01_E and Ref: 0377_IBERPHENOL_6_E)

Evaluation of the neuroprotective and antidiabetic potential of phenol-rich extracts from virgin olive oils by in vitro assays

In this work, phenol-rich extracts from ‘Cornicabra’ and ‘Picual’ virgin-olive oils (EVOOs) were examined, for the first time, to establish their capacity to inhibit key enzymes involved in Alzheimer's disease (AD) (acetylcholinesterase (AChE), butyrylcholinesterase (BuChE) and 5-lipoxygenase (LOX)), major depressive disorder (MDD) and Parkinson's disease (PD) (monoamine oxidases: hMAO-A and hMAO-B respectively), and diabetes mellitus (DM) (α-glucosidase and α-amylase). ‘Cornicabra’ displayed the best inhibitory activity against all enzymes, when compared to ‘Picual’: BuChE (IC50 = 156 ± 4 and 308 ± 33 mg mL−1), LOX (IC50 = 26 ± 0.5 and 37 ± 3 mg mL−1), hMAO-A (IC50 = 20 ± 2 and 37 ± 0.2 mg mL−1), hMAO-B (IC50 = 131 ± 7 and 215 ± 13 mg mL−1) and α-glucosidase (IC50 = 154 ± 17 and 251 ± 31 mg mL−1), respectively. The behaviour observed can be associated with the higher content of secoiridoids, lignans and phenolic acids in ‘Cornicabra’ EVOO.POCTEP | Ref. 0377_IBERPHENOL_6_EFundação para a Ciência e a Tecnologia | Ref. UID/QUI/50006/2013Norte Portugal Regional Operational Programme | Ref. NORTE-01-0145-FEDER-000024Xunta de Galici

Contribution of critical doses of iprovalicarb, mepanipyrim and tetraconazole to the generation of volatile compounds from Monastrell-based wines

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGThe individual effects of iprovalicarb, mepanipyrim, and tetraconazole on the volatile composition and aromatic profile of Monastrell-based wines were evaluated. To date, no studies about the effect of these fungicides on Monastrell-based wines are available, and the effect on other grape varieties is also unknown. Fungicides were added separately in the cellar to the grape must at two concentration levels (4 and 10 mg/kg for iprovalicarb and mepanipyrim and 1 and 2.5 mg/kg for tetraconazole). The aromatic composition of the final wines was analysed by gas chromatography using flame ionisation and ion trap mass selective detectors. In the presence of fungicides, the most significant variations were observed for isoamyl acetate and 2-phenylethyl acetate (increasing between 20 and 43% compared with the control wine) and ethyl caprate and caprylate (increasing between 12 and 68%). Consequently, treated wines showed a higher global odourant intensity, with increased fresh fruit notes.Ministerio de Economía y Competitividad | Ref. AGL2015-66491-C2-1-RAgencia Estatal de Investigación | Ref. PID2019-105061RB-C2

Characterization of virgin olive oils produced with autochthonous Galician varieties

The interest of Galician oil producers (NW Spain) in recovering the ancient autochthonous olive varieties Brava and Mansa has increased substantially in recent years. Virgin olive oils produced by co-crushing both varieties in two different proportions, reflecting the usual and most common practice adopted in this region, have gradually emerged for the production of virgin olive oils. Herein, the sensory and chemical characteristics of such oils were characterized by quality and genuineness-related parameters. The results of chemical analysis are discussed in terms of their effective contribution to the sensory profile, which suggests useful recommendations for olive oil producers to improve the quality of oils. Antioxidant compounds, together with aromas and coloured pigments were determined, and their contribution in determining the functional value and the sensory properties of oils was investigated. In general, given the high levels of phenolic compounds (ranging between 254 and 375 mg/kg oil), tocopherols (about 165 mg/kg oil) and carotenoids (10-12 mg/kg oil); these are oils with long stability, especially under dark storage conditions, because stability is reinforced with the contribution of chlorophylls (15-22 mg/kg oil). A major content of phenolic compounds, as well as a predominance of trans-2-hexen-1-al within odor-active compounds (from 897 to 1645 μg/kg oil), responsible for bitter sensory notes. This characterization allows to developing new antioxidant-rich and flavour-rich VOOs, when co-crushing with a higher proportion of Brava olives, satisfying the consumers' demand in having access to more healthy dishes and peculiar sensory attributes

Singular olive oils from a recently discovered Spanish North-Western cultivar: an exhaustive 3-year study of their chemical composition and in-vitro antidiabetic potential

In this work, the quality and physicochemical parameters, phenolic composition, and antidiabetic potential of olive oils obtained from olives belonging to centenarian olive trees of the so-called ‘Mansa de Figueiredo’ cultivar were evaluated during three consecutive crop seasons (2017–2019). The oils produced during the three crop years were classified as extra virgin based on the quality-related indices, sensory analysis, and the genuineness-related parameters. In addition, LC-ESI-TOF MS was used to get a comprehensive characterisation of the phenolic fraction while LC-ESI-IT MS was applied for quantitation purposes. The content of phenolic compounds (ranging from 1837 to 2434 mg/kg) was significantly affected by the harvest year due to the environmental conditions and ripening index. Furthermore, although significant differences in the inhibitory effects against the α-glucosidase enzyme for the EVOOs extracted throughout the three successive years were detected, all the studied EVOOs exhibited a stronger inhibitor effect than that found for acarbose.Agencia Estatal de Investigación | Ref. RTI2018-098633-B-I00FEDER/Junta de Andalucía | Ref. P20_00263FEDER/Junta de Andalucía | Ref. B-AGR-416-UGR18Ministerio de Universidades | Ref. FPU19/0070

Mepanipyrim residues on pasteurized red must influence the volatile derived compounds from Saccharomyces cerevisiae metabolism

The impact of mepanipyrim (Mep) and its corresponding commercial formulation (Mep Form) on Saccharomyces cerevisiae metabolites was assessed, separately, by using laboratory-scale wine fermentation assays on pasteurized red must. The presence of Mep did not alter the fermentation course. With regard to volatiles formed at the intracellular level by fermenting yeast cells, Mep residues affected mainly the acetate and ethyl ester biochemical pathways. In particular, the target acetates showed a notorious increment, >90%, in presence of commercial Mep Form at the higher dose assayed. The addition of Mep and Mep Form, at both tested levels, highly increased ethyl caprylate (between 42 and 63%) and ethyl caprate (between 36 and 60%) contents as the same as their respective fatty acid precursors. No important effects were observed on colour and non-volatile pyranoanthocyanins, probably due to the low anthocyanin content characteristic of pasteurized musts.Xunta de Galicia | Ref. EM2013/004POCTEP | Ref. 0377_IBERPHENOL_6_EMinisterio de Economía y Competitividad | Ref. AGL2015-66491-C2-1-