speciation of chitosan with low and high molecular weight carboxylates in aqueous solution

Quantitative data on the speciation of chitosan (310kDa) with low and high molecular weight carboxylates in aqueous solution are reported. The following carboxylic ligands were considered: monocarboxylate (butyrate); dicarboxylates (malonate, succinate, azelate); tricarboxylate (1,2,3-propanetricarboxylate); tetracarboxylate (1,2,3,4-butanetetracarboxylate); polyacrylates (2.0 and 20kDa); polymethacrylate (5.4kDa). The investigation was performed by potentiometry at t ¼ 25 � C, at low ionic strength (without addition of supporting electrolyte) and at I ¼ 0:15mol L � 1 (NaCl). For all the systems the formation of (chitosan)LHi species was found (L ¼carboxylic ligand; i ¼1 to 4 depending on the carboxylic ligand considered). The stability of proton–chitosan–carboxylate species depends on the number of carboxylic groups involved in the complexation, and it was possible to calculate a rough free energy value per bond DGn ¼� 15 � 2kJ mol � 1 . By using the stability data, the quantitative sequestering capacity of chitosan towards the carboxylates here considered [expressed as the–log(total chitosan concentration) necessary to bind 50% of carboxylate, i.e., pL50] was calculated for different pH values, at low ionic strength and at I ¼ 0:15mol L � 1 . The pL50 values, ranging from 3 to 7, show that chitosan is quite a strong sequestering agent towards carboxylates. Evidences were also obtained for the different behaviour between low and high molecular weight carboxylates

Filologia delle immagini

Engramma no. 195, “Filologia delle immagini”, edited by Maddalena Bassani, Concetta Cataldo, and Roberto Indovina, is a reflection on the iconography of myth and its re-elaboration on figured ceramics through the textual mediation of theatre. The essays here included explore the relationship between texts and images. The contributions by Concetta Cataldo, Antonio Maria Draià and Miriam Sabatucci are linked to the theme of “Pots & Plays” and accordingly analyze the interactions between Greek theatrical texts and vase painting of the fifth and the fourth centuries BC. Mariagrazia Ciani presents a review of Francesca Ghedini’s volume dedicated to history through images in the ancient world. We also include an interview with the actresses of the 2022 theatrical season and an update of the list of classic dramas performed by the Istituto Nazionale del Dramma Antico (INDA – National Institute of Ancient Drama) from 1914 to 2022 in Syracuse. Finally, a presentation of the exhibition “Argilla. Storie di viaggi. Un itinerario scientifico e didattico fra mari e millenni”, in Vicenza

Poly (ADP-ribose) polymerase 1 expression in fibroblasts of Down syndrome subjects

Abstract Down syndrome (DS) is the most common chromosomal disorder. It is featured by intellectual disability and is caused by trisomy 21. People with DS can develop some traits of Alzheimer disease at an earlier age than subjects without trisomy 21. Apoptosis is a programmed cell death process under both normal physiological and pathological conditions. Poly (ADP-ribose) polymerase 1 is a mediator of programmed-necrotic cell death and appears to be also involved in the apoptosis. The aim of the present work was to detect the intracellular distribution of PARP-1 protein using immunofluorescence techniques and the expression of PARP-1 mRNA in culture of fibroblasts of DS subjects. The analysis of the intracellular distribution of PARP-1 show a signal at the nuclear level in about 75 % of the cells of DS subjects with a slight uniformly fluorescent cytoplasm. In contrast, in about 65% of the analyzed fibroblasts of the normal subjects only a slight fluorescent was found. These observations have been confirmed by PARP-1 gene mRNA expression evaluation. The data obtained from this study strengthen the hypothesis that the over-expression of PARP-1 gene could have a role in the activation of the apoptotic pathways acting in the neurodegenerative processes in DS

LDOC1 expression in fibroblasts of patients with Down syndrome

Abstract Down syndrome (DS) is characterised by intellectual disability and is caused by trisomy 21. Apoptosis is a programmed cell death process and is involved in neurodegenerative diseases such as Alzheimer. People with DS can develop some traits of Alzheimer disease at an earlier age than subjects without trisomy 21. The leucine zipper, down regulated in cancer 1 (LDOC1) appears to be involved in the apoptotic pathways. The aim of the present work was to detect the presence of intracellular synthesis of LDOC1 protein and LDOC1 mRNA in fibroblast cultures from DS subjects. The western blot shows the presence of LDOC1 protein in fibroblasts of DS subjects but no evidence of LDOC1 protein in fibroblasts of normal subjects. LDOC1 gene mRNA expression is increased in fibroblasts from DS subjects compared to fibroblasts from normal subjects. The data obtained from this study strengthen the hypothesis that the over-expression of LDOC1 gene could play a role in determining the phenotype of individuals with DS but does not exclude that this results from apoptotic mechanisms

Speciation Studies of Bifunctional 3-Hydroxy-4-Pyridinone Ligands in the Presence of Zn2+ at Different Ionic Strengths and Temperatures

The acid-base properties of two bifunctional 3-hydroxy-4-pyridinone ligands and their chelating capacity towards Zn2+, an essential bio-metal cation, were investigated in NaCl aqueous solutions by potentiometric, UV-Vis spectrophotometric, and 1H NMR spectroscopic titrations, carried out at 0.15 ≤ I/mol -1 ≤ 1.00 and 288.15 ≤ T/K ≤ 310.15. A study at I = 0.15 mol L-1 and T = 298.15 K was also performed for other three Zn2+/Lz- systems, with ligands belonging to the same family of compounds. The processing of experimental data allowed the determination of protonation and stability constants, which showed accordance with the data obtained from the different analytical techniques used, and with those reported in the literature for the same class of compounds. ESI-MS spectrometric measurements provided support for the formation of the different Zn2+/ligand species, while computational molecular simulations allowed information to be gained on the metal-ligand coordination. The dependence on ionic strength and the temperature of equilibrium constants were investigated by means of the extended Debye-Hückel model, the classical specific ion interaction theory, and the van't Hoff equations, respectively

Combining nitric oxide release with anti-inflammatory activity preserves nigrostriatal dopaminergic innervation and prevents motor impairment in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine model of Parkinson's disease

Background Current evidence suggests a role of neuroinflammation in the pathogenesis of Parkinson's disease (PD) and in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of basal ganglia injury. Reportedly, nonsteroidal anti-inflammatory drugs (NSAIDs) mitigate DAergic neurotoxicity in rodent models of PD. Consistent with these findings, epidemiological analysis indicated that certain NSAIDs may prevent or delay the progression of PD. However, a serious impediment of chronic NSAID therapy, particularly in the elderly, is gastric, renal and cardiac toxicity. Nitric oxide (NO)-donating NSAIDs, have a safer profile while maintaining anti-inflammatory activity of parent compounds. We have investigated the oral activity of the NO-donating derivative of flurbiprofen, [2-fluoro-α-methyl (1,1'-biphenyl)-4-acetic-4-(nitrooxy)butyl ester], HCT1026 (30 mg kg-1 daily in rodent chow) in mice exposed to the parkinsonian neurotoxin MPTP. Methods Ageing mice were fed with a control, flurbiprofen, or HCT1026 diet starting ten days before MPTP administration and continuing for all the experimental period. Striatal high affinity synaptosomial dopamine up-take, motor coordination assessed with the rotarod, tyrosine hydroxylase (TH)- and dopamine transporter (DAT) fiber staining, stereological cell counts, immunoblotting and gene expression analyses were used to assess MPTP-induced nigrostriatal DAergic toxicity and glial activation 1-40 days post-MPTP. Results HCT1026 was well tolerated and did not cause any measurable toxic effect, whereas flurbiprofen fed mice showed severe gastrointestinal side-effects. HCT1026 efficiently counteracted motor impairment and reversed MPTP-induced decreased synaptosomal [3H]dopamine uptake, TH- and DAT-stained fibers in striatum and TH+ neuron loss in subtantia nigra pars compacta (SNpc), as opposed to age-matched mice fed with a control diet. These effects were associated to a significant decrease in reactive macrophage antigen-1 (Mac-1)-positive microglial cells within the striatum and ventral midbrain, decreased expression of iNOS, Mac-1 and NADPH oxidase (PHOX), and downregulation of 3-Nitrotyrosine, a peroxynitrite finger print, in SNpc DAergic neurons. Conclusions Oral treatment with HCT1026 has a safe profile and a significant efficacy in counteracting MPTP-induced dopaminergic (DAergic) neurotoxicity, motor impairment and microglia activation in ageing mice. HCT1026 provides a novel promising approach towards the development of effective pharmacological neuroprotective strategies against PD

Filologia delle immagini. Editoriale di Engramma 195

Engramma no. 195, “Filologia delle immagini”, edited by Maddalena Bassani, Concetta Cataldo, and Roberto Indovina, is a reflection on the iconography of myth and its re-elaboration on figured ceramics through the textual mediation of theatre. The essays here included explore the relationship between texts and images. The contributions by Concetta Cataldo, Antonio Maria Draià and Miriam Sabatucci are linked to the theme of “Pots & Plays” and accordingly analyze the interactions between Greek theatrical texts and vase painting of the fifth and the fourth centuries BC. Mariagrazia Ciani presents a review of Francesca Ghedini’s volume dedicated to history through images in the ancient world. We also include an interview with the actresses of the 2022 theatrical season and an update of the list of classic dramas performed by the Istituto Nazionale del Dramma Antico (INDA – National Institute of Ancient Drama) from 1914 to 2022 in Syracuse. Finally, a presentation of the exhibition “Argilla. Storie di viaggi. Un itinerario scientifico e didattico fra mari e millenni”, in Vicenza

Chaetomorpha linum in the bioremediation of aquaculture wastewater: Optimization of nutrient removal efficiency at the laboratory scale

Marine pollution from aquaculture wastewater is a widespread and increasing ecological problem. Algae, with their ability to remove surplus nutrients from wastewater, are a good tool for achieving more sustainable aquaculture. In this study, the capability of different biomasses of Chaetomorpha linum and Cladophora prolifera for the bioremediation of nutrient-rich (ammonium, nitrate and phosphate) seawater was compared. The results suggest that 10 g L−1C. linum is an excellent candidate for aquaculture wastewater bioremediation. However, the bioremediation efficiency of C. linum was significantly affected by seasonality, with the greatest performance in nutrient removal exhibited by algae harvested in summer. C. linum harvested in winter and acclimated to lab conditions for two months, significantly improved the removal efficiency of both ammonium and nitrate, while worsening that of phosphate. Irrespective of season and acclimation, the simultaneous presence of ammonium and nitrate in seawater strongly inhibited nitrate removal. Thus, we propose the use of a two-step system, tested at the laboratory scale, in which nutrient-enriched seawater can pass through two different algal ponds. C. linum was able to achieve almost complete removal of ammonium in 24 h in the first step, while the second step improved both nitrate and phosphate removal efficiency. The two-step system is an effective innovation for the use of algae in bioremediation of aquaculture wastewaters.Marine pollution from aquaculture wastewater is a widespread and increasing ecological problem. Algae, with their ability to remove surplus nutrients from wastewater, are a good tool for achieving more sustainable aquaculture. In this study, the capability of different biomasses of Chaetomorpha linum and Cladophora prolifera for the bioremediation of nutrient-rich (ammonium, nitrate and phosphate) seawater was compared. The results suggest that 10 g L−1C. linum is an excellent candidate for aquaculture wastewater bioremediation. However, the bioremediation efficiency of C. linum was significantly affected by seasonality, with the greatest performance in nutrient removal exhibited by algae harvested in summer. C. linum harvested in winter and acclimated to lab conditions for two months, significantly improved the removal efficiency of both ammonium and nitrate, while worsening that of phosphate. Irrespective of season and acclimation, the simultaneous presence of ammonium and nitrate in seawater strongly inhibited nitrate removal. Thus, we propose the use of a two-step system, tested at the laboratory scale, in which nutrient-enriched seawater can pass through two different algal ponds. C. linum was able to achieve almost complete removal of ammonium in 24 h in the first step, while the second step improved both nitrate and phosphate removal efficiency. The two-step system is an effective innovation for the use of algae in bioremediation of aquaculture wastewaters