Poly(N-isopropylacrylamide-co-N-vinylpyrrolidone) thermoresponsive microspheres: The low drug loading ensures the pulsatile release mechanism

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Cardiolipin drives cytochrome c proapoptotic and antiapoptotic actions

""\\"Cytochrome c (cytc) is pivotal in mitochondrial respiration and apoptosis. The heme-Fe-atom of native hexacoordinated horse heart cytc (hhcytc) displays a very low reactivity toward ligands and does not exhibit catalytic properties. However, on interaction with cardiolipin (CL), hhcytc changes its tertiary structure disrupting the heme-Fe-Met80 distal bond. The CL-hhcytc complex displays a very low midpoint potential, out of the range required for its physiological role, binds CO and NO with high affinity, facilitates peroxynitrite isomerization to NO(3)(-), and displays peroxidase activity. As a whole, the CL-hhcytc complex could play either proapoptotic effects, catalyzing lipid peroxidation and the subsequent hhcytc release into the cytoplasm, or antiapoptotic actions, such as scavenging peroxynitrite (i.e., protecting the mitochondrion from reactive nitrogen and oxygen species), and binding of CO and NO (i.e., inhibiting lipid peroxidation and hhcytc traslocation). Here, the CL-driven allosteric modulation of hhcytc properties is reviewed, highlighting proapoptotic and antiapoptotic actions. (C) 2011 IUBMB IUBMB Life, 63(3): 160-165, 2011\\""

Ibuprofen modulates allosterically NO dissociation from ferrous nitrosylated human serum heme-albumin by binding to three sites

Human serum albumin (HSA) is a monomeric allosteric protein. Here, the effect of ibuprofen on denitrosylation kinetics (k(off)) and spectroscopic properties of HSA-heme-Fe(II)-NO is reported. The k(off) value increases from (1.4 +/- 0.2) x 10(-4) s(-1), in the absence of the drug, to (9.5 +/- 1.2) x 10(-3) s(-1), in the presence of 1.0 x 10(-2) M ibuprofen, at pH 7.0 and 10.0 degrees C. From the dependence of k(off) on the drug concentration, values of the dissociation equilibrium constant for ibuprofen binding to to HSA-heme-Fe(II)-NO (K-1 = (3.1 +/- 0.4) x 10(-7) M, K-2= (1.7 +/- 0.2) x 10(-4) M. and K-3 (2.2 +/- .2) x 10(-3) M) were determined. The K-3 value corresponds to the HSA-heme-Fe(II)-NO determined by monitoring drug-dependent absorbance spectroscopic changes (H = (2.6 +/- 0.3) x 10(-3) M). Present data indicate that ibuprofen binds to the FA3-FA4 cleft (Sudlow's site II), to the FA6 site, and possibly to the FA2 pocket, inducing the hexa-coordination of HSA-heme-Fe(II)-NO and triggering the heme-ligand dissociation kinetics. (C) 2009 Elsevier Inc. All rights reserved

Ferrous Campylobacter jejuni truncated hemoglobin P displays an extremely high reactivity for cyanide - A comparative study

Campylobacter jejuni hosts two hemoglobins (Hbs). The Camplylobacter jejuni single-domain Hb (called Cgb) is homologous to the globin domain of flavohemoglobin, and it has been proposed to protect the bacterium against nitrosative stress. The second Hb is called Ctb (hereafter Cj-trHbP), belongs to truncated Hb group III, and has been hypothesized to be involved in O 2 chemistry. Here, the kinetics and thermodynamics of cyanide binding to ferric and ferrous Cj-trHbP [Cj-trHbP(III) and Cj-trHbP(II), respectively] are reported and analyzed in parallel with those of related heme proteins, with particular reference to those from Mycobacterium tuberculosis. The affinity of cyanide for Cj-trHbP(II) is higher than that reported for any known (in)vertebrate globin by more than three orders of magnitude (K = 1.2 × 10-6 m). This can be fully attributed to the highest (ever observed for a ferrous Hb) cyanide-binding association rate constant (kon = 3.3 × 103 m-1·s-1), even though the binding process displays a rate-limiting step (kmax = 9.1 s -1). Cj-trHbP(III) shows a very high affinity for cyanide (L = 5.8 × 10-9 m); however, cyanide association kinetics are independent of cyanide concentration, displaying a rate-limiting step (l max = 2.0 × 10-3 s-1). Values of the first-order rate constant for cyanide dissociation from Cj-trHbP(II)-cyanide and Cj-trHbP(III)-cyanide (koff =5.0 × 10-3 s -1 and loff ≥ 1 × 10-4 s-1, respectively) are similar to those reported for (in)vertebrate globins. The very high affinity of cyanide for Cj-trHbP(II), reminiscent of that of horseradish peroxidase(II), suggests that this globin may participate in cyanide detoxification. © 2008 The Authors

Ebolavirus and Marburgvirus: insight the Filoviridae family

Ebolavirus and Marburgvirus (belonging to the Filoviridae family) emerged four decades ago and cause epidemics of haemorrhagic fever with high case-fatality rates. The genome of filoviruses encodes seven proteins. No significant homology is observed between filovirus proteins and any known macromolecule. Moreover, Marburgvirus and Ebolavirus show significant differences in protein homology. The natural maintenance cycle of filoviruses is unknown, the natural reservoir, the mode of transmission, the epidemic disease generation, and temporal dynamics are unclear. Lastly, Ebolavirus and Marburgvirus are considered as potential biological weapons. Vaccine appears the unique therapeutic frontier. Here, molecular and clinical aspects of filoviral haemorrhagic fevers are summarized

The key role played by charge in the interaction of cytochrome c with cardiolipin

Cytochrome c undergoes structural variations upon binding of cardiolipin, one of the phospholipids constituting the mitochondrial membrane. Although several mechanisms governing cytochrome c/cardiolipin (cyt c/CL) recognition have been proposed, the interpretation of the process remains, at least in part, unknown. To better define the steps characterizing the cyt c-CL interaction, the role of Lys72 and Lys73, two residues thought to be important in the protein/lipid binding interaction, were recently investigated by mutagenesis. The substitution of the two (positively charged) Lys residues with Asn revealed that such mutations cancel the CL-dependent peroxidase activity of cyt c; furthermore, CL does not interact with the Lys72Asn mutant. In the present paper, we extend our study to the Lys → Arg mutants to investigate the influence exerted by the charge possessed by the residues located at positions 72 and 73 on the cyt c/CL interaction. On the basis of the present work a number of overall conclusions can be drawn: (i) position 72 must be occupied by a positively charged residue to assure cyt c/CL recognition; (ii) the Arg residues located at positions 72 and 73 permit cyt c to react with CL; (iii) the replacement of Lys72 with Arg weakens the second (low-affinity) binding transition; (iv) the Lys73Arg mutation strongly increases the peroxidase activity of the CL-bound protein

L'Università per la formazione delle educatrici e degli educatori al patrimonio storico-artistico: riflessioni a partire da una prima mappatura nazionale

L’ormai imprescindibile necessità educativa e comunicativa delle istituzioni museali invoca una sempre crescente specializza-zione dei professionisti incaricati di queste funzioni. Sebbene i re-quisiti delle educatrici e degli educatori, delle e dei responsabili dei servizi educativi siano ormai saldamente individuati, la nostra legislazione non riconosce tali figure professionali, aprendo di fatto a uno scollamento tra le necessità dei luoghi e degli istituti della cultura e i percorsi di formazione. Questi ultimi, non trovando riscon-tro nel riconoscimento professionale e dovendo rispondere a precise norme ministeriali in merito alla costruzione dei curricula formativi offerti ai vari livelli, dai diplomi di laurea ai corsi di dotto-rato, non possono che basare le proprie aperture didattiche all’educazione al patrimonio sulle sensibilità dei singoli Atenei, se non dei singoli docenti. Per verificare l’effettiva offerta formativa attualmente proposta dagli atenei nazionali è stata svolta una prima mappatura nazionale sui corsi di laurea di I e II livello, Scuole di Specializzazione e Master di I e II livello, in ambito storico-artistico

Staphylococcus aureus enterotoxin b down-regulates the expression of transforming growth factor-beta (TGF-β) signaling transducers in human glioblastoma

Background: It has been revealed that Staphylococcus aureus enterotoxin B (SEB) may feature anti-cancer and anti-metastatic advantages due to its ability to modify cell immunity processes and signaling pathways. Glioblastoma is one of the most aggressive human cancers; it has a high mortality nature, which makes it an attractive area for the development of novel therapies. Objectives: We examined whether the SEB could exert its growth inhibitory effects on glioblastoma cells partially through the manipulation of a key tumor growth factor termed transforming growth factor-beta (TGF-β). Materials and Methods: A human primary glioblastoma cell line, U87, was treated with different concentrations of SEB. The cell quantity was measured by the MTT assay at different exposure times. For molecular assessments, total ribonucleic acid (RNA) was extracted from either non-treated or SEB-treated cells. Subsequently, the gene expression of TGF-β transducers, smad2/3, at the messenger RNA (mRNA) level, was analyzed via a quantitative real-time polymerase chain reaction (qPCR) using the SYBR Green method. Significant differences between cell viability and gene expression levels were determined (Prism 5.0 software) using a one-way analysis of variance (ANOVA) test. Results: We reported that SEB could effectively down-regulate smad2/3 expression in glioblastoma cells at concentrations as quantity as 1 µg/mL and 2 µg/mL (P < 0.05 and P < 0.01, respectively). The SEB concentrations effective at regulating smad2/3 expression were correlated with those used to inhibit the proliferation of glioblastoma cells. Our results also showed that SEB was able to decrease smad2/3 expression at the mRNA level in a concentration- and time-dependent manner. Conclusions: We suggested that SEB could represent an agent that can significantly decrease smad2/3 expression in glioblastoma cells, leading to moderate TGF-β growth signaling and the reduction of tumor cell proliferation. © 2016, Ahvaz Jundishapur University of Medical Sciences