Pressurized hot water-assisted recovery of crude residual agar from a never-dried algae industry waste stream: A Box-Behnken design approach

The potential of using pressurized hot water extraction to valorize the remaining crude agar in Gelidium sesquipedale waste stream after an initial industrial extraction was investigated. In this process, a four-factor Box-Behnken design was coupled with a response surface methodology. The impact of the operating temperature (°C), the internal pressure (bar), the extraction time (min), and the algae concentration (% w: v), as well as their quadratic effects and two-way interactions, on the physicochemical properties of the residual agar, was analyzed. The yield (%), gel strength (g/cm2), gelling temperature (°C), melting temperature (°C), 3,6-anhydrogalactose content (%), and the sulfate content (%) were all considered in the evaluation. A multiple regression statistical model was used to fit all the experimental responses to a second-order polynomial equation that confirmed the suitability of the approach. Temperature of 120 °C, low pressure of 3.28 bar, and an extended extraction time of 150 min along with a 3% (w: v) algae concentration were projected to be optimum conditions for a high extraction yield of 17.03%. The strength of the recovered agar hydrogel oscillated between a minimum of 25 g/cm2 and a maximum of 350 g/cm2. The key parameters impacting the fluctuation of the sulfate content in the recovered agar (2% ≤ sulfate content ≤10%, with R2 = 79.8%) appeared to be the temperature and the algae concentration, in addition to the quadratic effect of the solid concentration. By adjusting the parameters, the process can accommodate the physicochemical properties of agar for wider range of applications.European Commission, Horizon 2020 program through the Marie-Curie Individual Fellowship (H2020-MSCA-IF-2019), with regards to the ALGWAS-BIOR project (Grant agreement number 898804). This work was also supported by the Junta de Castilla y León (JCyL) and the European Regional Development Fund (ERDF) [grant numbers BU301P18 and BU050P20]; as well as the Agencia Estatal de Investigación [grant number AEI /10.13039/501100011033]

Influence of three commercial graphene derivatives on the catalytic properties of a lactobacillus plantarum α-l-Rhamnosidase when used as immobilization matrices

The modification of carbon nanomaterials with biological molecules paves the way toward their use in biomedical and biotechnological applications, such as next-generation biocatalytic processes, development of biosensors, implantable electronic devices, or drug delivery. In this study, different commercial graphene derivatives, namely, monolayer graphene oxide (GO), graphene oxide nanocolloids (GOCs), and polycarboxylate-functionalized graphene nanoplatelets (GNs), were compared as biomolecule carrier matrices. Detailed spectroscopic analyses showed that GO and GOC were similar in composition and functional group content and very different from GN, whereas divergent morphological characteristics were observed for each nanomaterial through microscopy analyses. The commercial α-l-rhamnosidase RhaB1 from the probiotic bacterium Lactobacillus plantarum, selected as a model biomolecule for its relevant role in the pharma and food industries, was directly immobilized on the different materials. The binding efficiency and biochemical properties of RhaB1–GO, RhaB1–GOC, and RhaB1–GN composites were analyzed. RhaB1–GO and RhaB1–GOC showed high binding efficiency, whereas the enzyme loading on GN, not tested in previous enzyme immobilization studies, was low. The enzyme showed contrasting changes when immobilized on the different material supports. The effect of pH on the activity of the three RhaB1-immobilized versions was similar to that observed for the free enzyme, whereas the activity–temperature profiles and the response to the presence of inhibitors varied significantly between the RhaB1 versions. In addition, the apparent Km for the immobilized and soluble enzymes did not change. Finally, the free RhaB1 and the immobilized enzyme in GOC showed the best storage and reutilization stability, keeping most of their initial activity after 8 weeks of storage at 4 °C and 10 reutilization cycles, respectively. This study shows, for the first time, that distinct commercial graphene derivatives can influence differently the catalytic properties of an enzyme during its immobilization.European Union’s H2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No. 691095, Ministerio de Economiá y Competitividad (CTQ2016-75023-C2-1-P, CTQ2015-70371- REDT MetDrugs Network), and Junta de Castilla y Leon- FEDER grants BU076U16, BU079U16 and UBU-11-A

Interaction analysis of commercial graphene oxide nanoparticles with unicellular systems and biomolecules

The ability of commercial monolayer graphene oxide (GO) and graphene oxide nanocolloids (GOC) to interact with different unicellular systems and biomolecules was studied by analyzing the response of human alveolar carcinoma epithelial cells, the yeast Saccharomyces cerevisiae and the bacteria Vibrio fischeri to the presence of different nanoparticle concentrations, and by studying the binding affinity of different microbial enzymes, like the α-l-rhamnosidase enzyme RhaB1 from the bacteria Lactobacillus plantarum and the AbG β-d-glucosidase from Agrobacterium sp. (strain ATCC 21400). An analysis of cytotoxicity on human epithelial cell line A549, S. cerevisiae (colony forming units, ROS induction, genotoxicity) and V. fischeri (luminescence inhibition) cells determined the potential of both nanoparticle types to damage the selected unicellular systems. Also, the protein binding affinity of the graphene derivatives at different oxidation levels was analyzed. The reported results highlight the variability that can exist in terms of toxicological potential and binding affinity depending on the target organism or protein and the selected nanomaterial.European Union’s H2020 research and innovation programme under the Marie Skłodowska-Curie grant agreements Nº 691095, Nº 721642 and Nº 734873; Junta de Castilla y Leon-FEDER under grants Nº BU079U16, BU291P18 and BU022G18, and Ministerio de Economía y Competitividad CTQ2016-75023-C2-1-P and CTQ2015-70371-REDT MetDrugs Network (Spain

Reaction of non-symmetric schiff base metallo-ligand complexes possessing an oxime function with Ln ions

The preparation of non-symmetric Schiff base ligands possessing one oxime function that is associated to a second function such as pyrrole or phenol function is first described. These ligands, which possess inner N4 or N3O coordination sites, allow formation of cationic or neutral non-symmetric CuII or NiII metallo-ligand complexes under their mono- or di-deprotonated forms. In presence of Lanthanide ions the neutral complexes do not coordinate to the LnIII ions, the oxygen atom of the oxime function being only hydrogen-bonded to a water molecule that is linked to the LnIII ion. This surprising behavior allows for the isolation of LnIII ions by non-interacting metal complexes. Reaction of cationic NiII complexes possessing a protonated oxime function with LnIII ions leads to the formation of original and dianionic (Gd(NO3)5)2− entities that are well separated from each other. This work highlights the preparation of well isolated mononuclear LnIII entities into a matrix of diamagnetic metal complexes. These new complexes complete our previous work dealing with the complexing ability of the oxime function toward Lanthanide ions. It could open the way to the synthesis of new entities with interesting properties, such as single-ion magnets for exampl

Synthesis of Fluorogenic Arylureas and Amides and Their Interaction with Amines: A Competition between Turn-on Fluorescence and Organic Radicals on the Way to a Smart Label for Fish Freshness

We describe the synthesis of fluorogenic arylureas and amides and their interaction with primary or secondary amines under air and light in organic-aqueous mixtures to give rise to a new class of persistent organic radicals, described on the basis of their electron paramagnetic resonance (EPR), as well as UV–vis, fluorescence, NMR, and quantum mechanics calculations, and their prospective use as multi-signal reporters in a smart label for fish freshness.Funded by the NATO Science for Peace and Security Programme (Grant SPS G5536), the Junta de Castilla y León, Consejería de Educación y Cultura y Fondo Social Europeo (Grant BU263P18), and the Ministerio de Ciencia e Innovación (Grant PID2019-111215RB-100

Selectivity of a thiosemicarbazonatocopper(II) complex towards duplex RNA. Relevant noncovalent interactions both in solid state and solution

Thiosemicarbazones and their metal derivatives have long been screened as antitumor agents, and their interactions with DNA have been analysed. Herein, we describe the synthesis and characterization of compounds containing [CuL]+ entities (HL = pyridine-2-carbaldehyde thiosemicarbazone) and adenine, cytosine or 9-methylguanine, and some of their corresponding nucleotides. For the first time, crystal structures of adenine- and 9-methylguanine-containing thiosemicarbazone complexes are reported. To the best of our knowledge, the first study on the affinity thiosemicarbazone–RNA is also provided here. Experimental and computational studies have shown that [CuL(OH2)]+ entities at low concentration intercalate into dsRNA poly(rA)·poly(rU) through strong hydrogen bonds involving uracil residues and π–π stacking interactions. In fact, noncovalent interactions are present both in the solid state and in solution. This behaviour diverges from that observed with DNA duplexes and creates an optimistic outlook in achieving selective binding to RNA for subsequent possible medical applications.Obra Social “la Caixa” (OSLC-2012-007), Ministerio de Economía y Competitividad and FEDER funds (CTQ2013-48937-C2-1-P, CTQ2015-70371- REDT, MAT2012-34740 and CTQ2014-58812-C2-2-R), Junta de Castilla y León (BU237U13), the Basque Government (IT-779- 13), Gerencia Regional de Salud, Consejería de Sanidad, Junta de Castilla y León (GRS 1023/A/14 and GR172)

Synthesis, crystal structure, spectroscopic characterization, DFT calculations and cytotoxicity assays of a new cu(II) complex with an acylhydrazone Ligand derived from thiophene

A new Cu(II) complex is synthetized by the reaction of copper nitrate and a N-acylhydrazone ligand obtained from the condensation of o-vanillin and 2-thiophecarbohydrazide (H2L). The solid-state structure of [Cu(HL)(H2O)](NO3)·H2O, or CuHL for simplicity, was determined by X-ray diffraction. In the cationic complex, the copper center is in a nearly squared planar environment with the nitrate interacting as a counterion. CuHL was characterized by spectroscopic techniques, including solid-state FTIR, Raman, electron paramagnetic resonance (EPR) and diffuse reflectance and solution UV-Vis electronic spectroscopy. Calculations based on the density functional theory (DFT) assisted the interpretation and assignment of the spectroscopic data. The complex does not show relevant antioxidant activity evaluated by the radical cation of 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) method, being even less active than the free ligand as a radical quencher. Cytotoxicity assays of CuHL against three human tumor cell lines, namely MG-63, A549 and HT-29, revealed an important enhancement of the effectiveness as compared with both the ligand and the free metal ion. Moreover, its cytotoxic effect was remarkably stronger than that of the reference metallodrug cisplatin in all cancer cell lines tested, a promissory result in the search for new metallodrugs of essential transition metals.Fil: Rodríguez, María R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; ArgentinaFil: Balsa, Lucia Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; ArgentinaFil: Piro, Oscar Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Etcheverría, Gustavo A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: García Tojal, Javier. Universidad de Burgos; EspañaFil: Pis Diez, Reinaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; ArgentinaFil: Leon, Ignacio Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; ArgentinaFil: Parajón Costa, Beatriz Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; ArgentinaFil: Gonzalez Baro, Ana Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; Argentin

Revisiting the thiosemicarbazonecopper(II) reaction with glutathione. Activity against colorectal carcinoma cell lines

Thiosemicarbazones (TSCs), and their copper derivatives, have been extensively studied mainly due to the potential applications as antitumor compounds. A part of the biological activity of the TSC-CuII complexes rests on their reactivity against cell reductants, as glutathione (GSH). The present paper describes the structure of the [Cu(PTSC)(ONO2)]n compound (1) (HPTSC =pyridine-2-carbaldehyde thiosemicarbazone) and its spectroscopic and magnetic properties. ESI studies performed on the reaction of GSH with 1 and the analogous [{Cu (PTSC*)(ONO2)}2] derivative (2, HPTSC* =pyridine-2-carbaldehyde 4N-methylthiosemicarbazone) show the absence of peaks related with TSC-Cu-GSH species. However GSH-Cu ones are detected, in good agreement with the release of CuI ions after reduction in the experimental conditions. The reactivity of 1 and 2 with cytochrome c and myoglobin and their activities against HT-29 and SW-480 colon carcinoma cell lines are compared with those shown by the free HPTSC and HPTSC* ligands.Obra Social “la Caixa” (OSLC-2012-007), Ministerio de Economía y Competitividad and FEDER funds (CTQ2013-48937-C2-1-P, CTQ2015-70371-REDT, MAT2015-66441-P, BIO2015-67358-C2-2-P), Junta de Castilla y León (BU237U13), Gerencia Regional de Salud, Consejería de Sanidad, Junta de Castilla y León (GRS 1023/A/14), the Basque Government (project IT-779-13

Cu(ii) and Zn(ii) complexes with a poly-functional ligand derived from o-vanillin and thiophene. Crystal structure, physicochemical properties, theoretical studies and cytotoxicity assays against human breast cancer cells

The interaction of a poly-functional ligand derived from o-vanillin and 2-thiophenemethylamine (oVATPNH2) with transition metal ions Cu(II) and Zn(II) leads to the formation of stable coordination compounds, namely [Cu(oVATPNH2)2] and [Zn(oVATPNH2)2]. Their crystal structures have been determined by X-ray diffraction methods. Two molecules of the deprotonated ligand acting in a bidentate fashion build a nearly square planar environment around Cu(II) and a distorted tetrahedral coordination arrangement for Zn(II). The complexes were characterized by spectroscopic techniques, including solid state FTIR, Raman, EPR and diffuse reflectance and solution UV-vis and EPR. Their thermal behavior has been analyzed by means of TGA and DTA. DFT theoretical studies, using computational methods based on DFT, were employed to assist the interpretation and assignment of spectroscopic data. Cytotoxicity assays against two human breast cancer cell lines, namely MCF-7 and MDA-MB-231, revealed an enhancement of the effectiveness of the complexes as compared with both the ligand and the free metal ions. The results for the copper compound are promising, as its cytotoxic effect was stronger than the reference metallodrug cisplatin in both cancer cell lines tested.CONICET-CCT-La Plata (PIP 0651 and 0034), ANPCyT (PICT 2016-1574) and UNLP (11/X-473) (Argentina) and also by Consejerı´a de Educacio´n CyL and FFEDER BU076U16, BU022G18 and Ministerio de Economı´a y Competitividad CTQ2016-75023-C2-1-P and CTQ2015-70371- REDT MetDrugs Network (Spai

Synthesis, crystal structure and cytotoxicity assays of a copper(II) nitrate complex with a tridentate ONO acylhydrazone ligand. Spectroscopic and theoretical studies of the complex and its ligand

The new copper complex, [Cu(HL)(OH2)2](NO3), including the tridentate N-acyhydrazone derived from 4-hydroxy-benzohydrazide and 2-hydroxy-3-methoxybenzaldehyde, (H2L), has been synthesized and characterized in the solid state and in solution by spectroscopic (FTIR, Ra, UV–vis, EPR) methods. The results were compared with those obtained for the hydrazone ligand and complemented with computational methods based on DFT. The crystal structure of the complex has been determined by X-ray diffraction. It crystallizes in the triclinic space group with Z = 2. The Cu(II) ion is in a distorted square pyramidal environment, coordinated to a planar HL- anion acting as a tridentate ligand. The 5-fold coordination is completed with two water molecules. It is arranged in the lattice as H-bonded ribbon-like polymers that extends along the [1 2 1] crystal direction. The cytotoxicity of the complex together with that of the H2L ligand and the copper ion were evaluated in vitro against five different human cancer cell lines namely A549 (lung), MG-63 (bone), MCF-7 and MDA-MB-231 (breast) and Jurkat (leukemia). The copper complex inhibits the cell viability in a dose dependent manner with a greater potency than the H2L ligand and the free copper ion displaying even higher antitumor activity than the well-known anticancer metallodrug cisplatin.CONICET (PIP 11220130100651CO and PIP 0034), UNLP (111/X673) and ANPCyT (PICT 2014-2223) of Argentina. Consejería de Educación CyL and FFEDER BU076U16, BU022G18 and Ministerio de Economía y Competitividad CTQ2016-75023-C2-1-P and CTQ2015-70371-REDTMetDrugs Network (Spain