Search results for "algue"
showing 10 items of 21 documents
Prominence and centralization: a two-way contrast between lexical and epenthetic non-labial high vowels in Algherese Catalan
2015
Algherese Catalan has the peculiarity of presenting an inserted [i] vowel across words in order to avoid certain consonant codas. In this study, we compare five acoustic features of this epenthetic segment (i.e., duration, intensity, and the three first formants) with those of lexical /i/ vowels, both stressed and unstressed. The results indicate that the three vowels present differences only with respect to duration, F2 and, to a lesser extent, F3. The second formant values decline progressively from the lexical stressed vowels to the inserted unstressed segments, with lexical unstressed segments at an intermediate point. This gradation mirrors the relative prominence of each vowel. The di…
Ceratium furcoides (Levander) Langhans in reservoirs at the Ebro watershed, Spain and Sao Paulo state, Brazil
2022
This study compares the morphological characteristics of the dinoflagellate Ceratium furcoides from three Ebro basin reser¬voirs (Spain) and from six reservoirs at São Paulo state (Brazil) with the aim to identify the distinct morphotypes of Ceratium furcoides in Spain and Brazil. We studied the physical and chemical variables to determine the trophic state of each reservoir. Unlike Ceratium hirundinella, Ceratium furcoides is not a frequent species within the plankton community at Ebro Basin reservoirs, however, this species has been responsible of one monospecific bloom at El Val reservoir. Nevertheless, both Ce-ratium species are considered invasive in South America. Ceratium furcoides h…
Pulsed electric field (PEF) recovery of biomolecules from Chlorella: Extract efficiency, nutrient relative value, and algae morphology analysis
2023
This study investigated the effects of pulsed electric field (PEF) (3 kV/cm, 44 pulses, 99 kJ/kg), solvent (H2O or 50 % DMSO) and time (0, 10, 20, 30, 60, 90, 120 and 180 min) on the extraction of Chlorella antioxidant biomolecules and minerals. The results showed that PEF treatment increased the biomolecules recovery. For the extraction time of 120 min, more proteins and polyphenols were obtained using water, while more chlorophyll a and b, and carotenoids were obtained using 50 % DMSO as the extraction solvent. The extracts mineral concentration (PEF vs control) were analysed including Mg, P, Ca, Fe and Zn, and the Relative Nutrient Values results indicated that Chlorella H2O-extracts cou…
Influence of Geographical Location of Spirulina (Arthrospira platensis) on the Recovery of Bioactive Compounds Assisted by Pulsed Electric Fields
2022
Spirulina (Arthrospira platensis) has been consumed by humans since ancient times. It is rich in high added-value compounds such as chlorophylls, carotenoids and polyphenols. Pulsed electric fields (PEF) is an innovative non-thermal technique that improves the extraction of bioactive compounds from diverse sources. PEF pre-treatment (3 kV/cm, 100 kJ/kg) combined with supplementary extraction with binary solvents at different times was evaluated to obtain the optimal conditions for extraction. In addition, the results obtained were compared with conventional treatment (without PEF pre-treatment and constant shaking) and different strains of Spirulina from diverse geographical locations. The …
The impact of liquid-pressurized extracts of Spirulina, Chlorella and Phaedactylum tricornutum on in vitro antioxidant, antiinflammatory and bacteria…
2022
The impact of Spirulina, Chlorella and Phaeodactylum tricornutum (P. tricornutum) microalgal extracts obtained by pressurized liquid extraction (PLE) on antioxidant and anti-inflammatory activities, microbial growth and in vitro gut microbiota composition was evaluated. PLE, compared to conventional extraction, led to a significant (p < 0.05) increase in proteins, carbohydrates, polyphenols, and antioxidant capacities of the three microalgal extracts. Moreover, Spirulina and P. tricornutum extracts significantly (p < 0.05) reduced the in vitro activation of the inflammatory NF-κB pathway. The microalgal extracts had also an inhibitory effect on the pathogenic bacteria while potential benefi…
Modeling Macroalgal Forest Distribution at Mediterranean Scale: Present Status, Drivers of Changes and Insights for Conservation and Management
2020
Macroalgal forests are one of the most productive and valuable marine ecosystems, but yet strongly exposed to fragmentation and loss. Detailed large-scale information on their distribution is largely lacking, hindering conservation initiatives. In this study, a systematic effort to combine spatial data on Cystoseira C. Agardh canopies (Fucales, Phaeophyta) was carried out to develop a Habitat Suitability Model (HSM) at Mediterranean scale, providing critical tools to improve site prioritization for their management, restoration and protection. A georeferenced database on the occurrence of 20 Cystoseira species was produced collecting all the available information from published and grey lit…
Microalgae community structure analysis based on 18S rDNA amplification from DNA extracted directly from soil as a potential soil bioindicator
2005
International audience; Soil algae are photosynthetically active microorganisms showing changeable community structure, depending on the soil type, the agricultural practices and the application of pesticides. To characterise algal community structure, molecular approaches complementary to classical microbiological approaches based on the isolation and the culture of soil algae are required. Our study describes a polymerase chain reaction (PCR) approach targeting algal 18S rDNA sequences of desoxyribonucleic acid (DNA) samples extracted either from unialgal eukaryotic microalgae culture, complex assemblages of microalgae populations or natural soil communities. Our first results showed that…
Les microalgues et cyanobactéries des sols : quels apports pour l’écotoxicologie terrestre
2016
Les microorganismes photosynthétiques (cyanobactéries et microalgues) des sols pourraient constituer des bioindicateurs pertinents à l’égard des pressions phytosanitaires, à l’instar des milieux aquatiques. Néanmoins, les connaissances disponibles sur leur écologie dans les sols et leurs réponses aux stress sont limitées. Des développements méthodologiques (biochimiques et moléculaires) ont été réalisés afin d’identifier des marqueurs biochimiques et moléculaires pertinents pour décrire les effets de phytosanitaires sur la biomasse et la diversité des communautés microalgales. Des études en microcosmes contrôlés au laboratoire, complétés par des suivis au champ (systèmes de culture Biologiq…
Characterisation of NO synthases from the alga Klebsormidium nitens
2022
Nitric oxide (NO) is an important cellular signaling molecule regulating various physiological processes, in both animals and plants. In animals, NO synthesis is mainly catalyzed by NO synthase (NOS) enzymes. In plants, NOS-like activities sensitive to mammalian NOS inhibitors have been measured, although no sequences encoding mammalian NOS have been found in land plants. Interestingly, we identified NOS-like sequences in about twenty algae species. These latter include the filamentous Charophyta green algae Klebsormidium nitens, a biological model to study the early transition step from aquatic algae to land plants. Currently, two NOS were identified in K. nitens genome: i) KnNOS1 which po…
Assessment of cross-flow filtration as microalgae harvesting technique prior to anaerobic digestion: Evaluation of biomass integrity and energy demand
2018
[EN] In the present study, the effect of cross-flow filtration (CFF) on the overall valorization of Chlorella spp. microalgae as biogas was assessed. The effect of CFF on microalgae cell integrity was quantified in terms of viability which was correlated with the anaerobic biodegradability. The viability dropped as the biomass concentration increased, whereas anaerobic biodegradability increased linearly with the viability reduction. It was hypothesized that a stress-induced release and further accumulation of organic polymers during CFF increased the flux resistance which promoted harsher shear-stress conditions. Furthermore, the volume reduction as the concentration increased entailed an …