Biocompounds recovery from Spirulina by conventional and ohmic heating methodologies: chemical and biological properties

Extracting the totality of bio-compounds with industrial interest from Cyanobacterium is often prevented by the intrinsic rigidity of its cell wall. In this sense, the present study focuses on evaluating the influence thermal batch extraction (conventional extraction technologies) and ohmic heating (OH) assisted extraction (considered a greener alternative technology) in blue green microalgae Arthrospira platensis (Spirulina) cell disruption for bioactive fractions recovery. The proximal composition of Spirulina was initially determined. The maximum protein content (i.e., CPhycocyanin), total carbohydrates (TC) and total phenolic compounds (TPC) extracted in water at different times (30-120 min) and temperatures (30-51 ºC) was quantified after the conventional and OH- assisted extraction. The freeze-thawing process was used as control. The antioxidant activity (i.e., FRAP and DPPH assays) of the obtained extracts was assessed. Results showed that with the freeze-thawing process, traditionally used for the recovery of bio- compounds from Spirulina, the concentration of C-phycocyanin was approx. 42 mg/g of Spirulina, 26 mgGlcE/g Spirulina of TC and 9 mgGAE/g Spirulina of TPC. Using OH-assisted extraction, the maximum of C-Phycocyanin content obtained was 45 mg/g of Spirulina (obtained at 37 ºC, 30 min), the maximum carbohydrates content was 40 mgGlcE/g Spirulina and the maximum TPC was 10 mgGAE/g Spirulina. On the other hand, using conventional thermal treatment it can be observed that, under the same conditions, the bioactive compounds recovery decreased to 35 mg/g, 20 mgGlcE/g Spirulina for C-phycocyanin concentration and TC (p<0.05), respectively. The concentration in phenolic compounds is not so affected, but even so the ohmic heating potentiates the extraction of these secondary metabolites. The antioxidant activity of the extracts there was not different between conventional treatments andOH. Thus, the results indicated that OH is a good alternative to conventional methods aiming at the extraction of intracellular components with a decrease in processing time and energy costs associated with the extraction process, which together with an easy upscale make OH an interesting methodology for use in the industrial production of microalgae colorants and bioactive supplements.info:eu-repo/semantics/publishedVersio

Influence of thermal and electrical effects of ohmic heating on C-phycocyanin properties and biocompounds recovery from Spirulina platensis

Spirulina platensis is interesting for the food industry due to its overall composition and high content in C-phycocyanin. However, the sensitivity of C-phycocyanin makes its extraction a delicate process. The present study focuses on assessing the use of ohmic heating (OH) in the recovery of C-phycocyanin and other relevant compounds as an alternative method to freeze-thawing or conventional heating. Different ohmic and conventional heating treatments were applied both to purified C-phycocyanin and Spirulina powder. Evaluation of fluorescence and circular dichroism showed that moderated electric fields increased C-phycocyanin stability. This was confirmed in the extraction trials which revealed that OH assisted extraction at higher temperatures (44°C), and shorter times (30min) allowed significant higher extraction yield of C-phycocyanin (45 mg/gdw Spirulina), in comparison with conventional heating and freeze-thawing. OH allowed also up to 80% higher yields in phenolic compounds and carbohydrates.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit and BioTecNorte operation (NORTE-01-0145-FEDER000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. The study was also supported by the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant (MSCA-RISE; FODIAC; 778388) and project OH2O – POCI-01-0145-FEDER-029145 (FCT and COMPETE2020). Pedro Santos is recipient of a fellowship supported by a doctoral advanced training (call NORTE-69-2015-15), funded by the European Social Fund under the scope of Norte2020 - Programa Operacional Regional do Norte (NORTE-08-5369-FSE-000036).info:eu-repo/semantics/publishedVersio

Rotondas red eggplant: nutritional characterization and extractionof high added value biocompounds using emerging electrotechnologies

Rotondas Red Eggplant belongs to the family of Solanum aethiopicum species, cultivated in a specific area of Potenza (Basilicata, Italy) and has gained the Protected Designation of Origin certification. Recently, Red Eggplant was associated with different biological properties, related to health benefits, as antioxidant, hypoglycemic, antihypertensive and hypolipidemic, probably due to its chemical composition. The search for "greener" technologies has been one of the focus of research, having in mind industrial applications. In this sense, electrotechnologies, such as ohmic heating (OH), have been explored, showing to have potentially lower energy costs, higher extraction yields, being less time consuming and increasing the biocompounds chemical stability. The aim of this study was to determine the chemical/nutritional composition of Red Eggplant and to assess conventional and OH methods in the extraction and recovery of the main bio-compounds present in this material. Red Eggplant was characterized for the nutritional profile (AOAC procedures): proteins, carbohydrates, total extractives, lipids, ash and minerals. The selected conditions for the extraction of the main biocompounds, for conventional and OH methods, were: solid/liquid ratio 1:10 (w:v), 80 °C, 25 min and water or mixture of 50% (v/v) ethanol/water as a solvent. Subsequently, assays were carried out to determine the content of proteins (Bradford), total carbohydrates (phenolsulfuric acid) and phenolics (Folin-Ciocalteu), and antioxidant activity (FRAP and DPPH) of the obtained extracts. Monosaccharides profile after hydrolysis and phenolics were also quantified by HPLC. Results showed that carbohydrates were the major macronutrient, followed by protein, lipids and ash. K, Ca and Mg were the major minerals. Regarding the monosaccharide composition, glucose, fructose, xylose and arabinose were the most abundant sugars. Ethanolic extractives represented approximately 46 % of the Red Eggplant composition. Independently of the solvent, higher amounts of polyphenols, proteins and carbohydrates were extracted when OH was applied. Moreover, OH extracts showed greater antioxidant activity compared to extracts obtained by the conventional extraction method. According to the polyphenol profile of the extracts the main compounds found were taxifolin, rutin and rosmarinic acid. These results demonstrate the potential of this vegetable to be used for nutraceuticals or functional food.The authors wish to thank for the financial support to funding program Marie Skłodowska-Curie grant (MSCA-RISE; FODIAC; 778388). Pedro Santos is recipient of a fellowship supported by a doctoral advanced training (call NORTE-69-2015-15), funded by the European Social Fund under the scope of Norte2020 - Programa Operacional Regional do Norte (NORTE-08-5369-FSE-000036). Zlatina Genisheva is supported by the project OH2O (POCI-01-0145-FEDER-029145) funded by FCT and Fundo Europeu de Desenvolvimento Regional (FEDER) under the scope of Programa Operacional de Competividade e Internacionalizaçao (POCI)-COMPETE 2020 and Portugal 2020.info:eu-repo/semantics/publishedVersio

Thr 163 Phosphorylation Causes Mcl-1 Stabilization when Degradation is Independent of the Adjacent GSK3-Targeted Phosphodegron, Promoting Drug Resistance in Cancer

The antiapoptotic Bcl-2 family member Mcl-1 is a PEST protein (containing sequences enriched in proline, glutamic acid, serine, and threonine) and is subject to rapid degradation via multiple pathways. Impaired degradation leading to the maintenance of Mcl-1 expression is an important determinant of drug resistance in cancer. Phosphorylation at Thr 163 in the PEST region, stimulated by 12-O-tetradecanoylphorbol acetic acid (TPA)-induced activation of extracellular signal-regulated kinase (ERK), is associated with Mcl-1 stabilization in BL41-3 Burkitt lymphoma cells. This contrasts with the observation that Thr 163 phosphorylation in normal fibroblasts primes glycogen synthase kinase (GSK3)-induced phosphorylation at Ser 159, producing a phosphodegron that targets Mcl-1 for degradation. In the present follow-up studies in BL41-3 cells, Mcl-1 degradation was found to be independent of the GSK3-mediated pathway, providing a parallel to emerging findings showing that Mcl-1 degradation through this pathway is lost in many different types of cancer. Findings in Mcl-1-transfected CHO cells corroborated those in BL41-3 cells in that the GSK3-targeted phosphodegron did not play a major role in Mcl-1 degradation, and a phosphomimetic T163E mutation resulted in marked Mcl-1 stabilization. TPA-treated BL41-3 cells, in addition to exhibiting Thr 163 phosphorylation and Mcl-1 stabilization, exhibited an ∼10-fold increase in resistance to multiple chemotherapeutic agents, including Ara-C, etoposide, vinblastine, or cisplatin. In these cancer cells in which Mcl-1 degradation is not dependent on the GSK3/phosphodegron-targeted pathway, ERK activation and Thr 163 phosphorylation are associated with pronounced Mcl-1 stabilization and drug resistance – effects that can be suppressed by inhibition of ERK activation

New Insight on the Bioactivity of Solanum aethiopicum Linn. Growing in Basilicata Region (Italy): Phytochemical Characterization, Liposomal Incorporation, and Antioxidant Effects

Food extract’s biological effect and its improvement using nanotechnologies is one of the challenges of the last and the future decades; for this reason, the antioxidant effect of scarlet eggplant extract liposomal incorporation was investigated. Scarlet eggplant (Solanum aethiopicum L.) is a member of the Solanaceae family, and it is one of the most consumed vegetables in tropical Africa and south of Italy. This study investigated the antioxidant activity and the phytochemical composition of S. aethiopicum grown in the Basilicata Region for the first time. The whole fruit, peel, and pulp were subjected to ethanolic exhaustive maceration extraction, and all extracts were investigated. The HPLC-DAD analysis revealed the presence of ten phenolic compounds, including hydroxycinnamic acids, flavanones, flavanols, and four carotenoids (one xanthophyll and three carotenes). The peel extract was the most promising, active, and the richest in specialized metabolites; hence, it was tested on HepG2 cell lines and incorporated into liposomes. The nanoincorporation enhanced the peel extract’s antioxidant activity, resulting in a reduction of the concentration used. Furthermore, the extract improved the expression of endogenous antioxidants, such as ABCG2, CAT, and NQO1, presumably through the Nrf2 pathway

Mean-field cooperativity in chemical kinetics

We consider cooperative reactions and we study the effects of the interaction strength among the system components on the reaction rate, hence realizing a connection between microscopic and macroscopic observables. Our approach is based on statistical mechanics models and it is developed analytically via mean-field techniques. First of all, we show that, when the coupling strength is set positive, the model is able to consistently recover all the various cooperative measures previously introduced, hence obtaining a single unifying framework. Furthermore, we introduce a criterion to discriminate between weak and strong cooperativity, based on a measure of "susceptibility". We also properly extend the model in order to account for multiple attachments phenomena: this is realized by incorporating within the model $p$-body interactions, whose non-trivial cooperative capability is investigated too.Comment: 25 pages, 4 figure

Detección de leptospiras patógenas en tejido renal de murciélagos de Corrientes, Argentina

Existen muchos animales que participan en la transmisión de diferentes serovares de leptospiras. Los murciélagos han acrecentado su presencia en zonas urbanas; este cambio de hábitat se atribuye a razones de origen antropogénico y ha elevado las probabilidades de contacto entre quirópteros, seres humanos y animales domésticos. El objetivo del trabajo fue identificar, mediante una reacción en cadena de la polimerasa (PCR sencilla), la infección natural de especies de leptospiras patógenas en quirópteros colectados durante los años 2010 a 2012 en la ciudad de Corrientes. Para la captura se utilizaron redes de mano y trampas balde. La identificación de los quirópteros se efectuó en base a su características fenotípicas y morfométricas, determinándose la presencia de ejemplares de tres de las cuatro familias existentes en Argentina. Los animales fueron sacrificados bajo anestesia de hidrato de cloral 20%, obteniéndose muestras de tejido renal. Se realizó el procedimiento de extracción de ácido desoxirribonucleico; se amplificaron 2 genes en PCR sencillas separadas, un gen mitocondrial, mt DNA 12S/16S como control de especie y luego, en las mismas muestras, se amplificó parte de los genes LipL32. Se detectó presencia de ADN de leptospiras en el 20% de los quirópteros, siendo éste el primer hallazgo por PCR publicado para murciélagos del país. Revelar la presencia de ADN de leptospiras resulta de gran importancia, debido a su utilidad en los casos en que la búsqueda molecular del patógeno ha sido no detectable

Detección y diferenciación molecular de Leptospira sp. utilizando diferentes técnicas de extracción de ADN

Existen diversas estrategias diagnósticas para identificar leptospiras, siendo la reacción en cadena de la polimerasa (PCR) una técnica de alta sensibilidad y especificidad. El presente trabajo tuvo como objetivo optimizar técnicas de extracción de ADN a partir de cultivos bacterianos y establecer condiciones de PCR multiplex para diferenciar leptospiras saprófitas de patógenas. Para ello se ensayaron técnicas de bromuro de cetiltrimetil amonio (CTAB) y hervido (boiling). Se analizaron dos secuencias de ácidos nucleicos, correspondientes a una fracción de un gen conservado en ambos grupos de bacterias (ARNr 16S) y otra procedente de una fracción de un gen (LipL32) presente sólo en especies de leptospiras patógenas, las cuales dieron amplicones de 474 y 430 pb respectivamente, utilizándose como controles positivos de amplificación muestras de cultivos bacterianos de Leptospira icteroahemorragiae, L. canicola y apatógena (Patoc I), utilizando agua como control negativo. Se concluyó que no existen diferencias en la perdurabilidad del ADN extraído a partir de cepas de referencia al comparar el método de digestión con el detergente CTAB y el de boiling y sus variantes. Considerando el más bajo costo y menor tiempo de desarrollo, este último resultó la mejor alternativa para la obtención de moldes para amplificación por PCR

Detección de Leishmania (Viannia) braziliensis en gato doméstico de Corrientes, Argentina, por técnicas de biología molecular

Ruiz, R.M.; Ramírez, N.N.; Alegre, A.E.; Bastiani, C.E.; De Biasio, M.B.: Detección de Leishmania (Viannia) braziliensis en gato doméstico de Corrientes, Argentina, por técnicas de biología molecular. Rev vet 26: 2, 147-150, 2015