Halogen Bonding Controls Selectivity of FRET Substrate Probes for MMP-9

SummaryMatrix metalloproteinases (MMPs) are a large family of zinc-dependent endoproteases that catalyze cleavage of extracellular matrix and nonmatrix proteins. MMPs play a role in tissue remodeling, and their uncontrolled activity is associated with number of diseases, including tumor metastasis. Thus, there is a need to develop methods to monitor MMP activity, and number of probes has been previously described. The key problem many probes encounter is the issue of selectivity, since 23 human MMPs, despite playing different physiological roles, have structurally similar active sites. Here, we introduce the halogen bonding concept into the probe design and show that the probe containing iodine exhibits an unprecedented selectivity for MMP-9. We provide structure-based explanation for the selectivity, confirming that it is due to formation of the halogen bond that supports catalysis, and we highlight the value of exploring halogen bonding in the context of selective probe design

The effect of the carbon fibres diameter on cell response

W ramach pracy otrzymano włókninę zbudowaną z włókien o różnych średnicach i wielkości, której mikrostruktura posiada biomimetyczny charakter, tzn. składa się z włókien o średnicach zbliżonych do średnic włókien występujących w tkankach. Badania biologiczne wykazały, że włókna o niskich średnicach są gorzej tolerowane przez tkanki.A three dimensional fibrous material, made from fibres differing in diameters and porosity, has been designed and prepared. These materials will constitute a 3D scaffold containing fibrous components mimicking the structure of natural tissue. The biological studies indicate that the fibres with bigger diameter allow for more intense and quick regeneration of surrounding tissue

Mitochondrial DNA Variability in Bosnians and Slovenians

Summary Mitochondrial DNA variability in two Slavonic-speaking populations of the northwestern Balkan peninsula, Bosnians (N = 144) and Slovenians (N = 104), was studied by hypervariable segments I and II (HVS I and II) sequencing and restriction fragment-length polymorphism (RFLP) analysis of the mtDNA coding region

Neuronal Conduction of Excitation without Action Potentials Based on Ceramide Production

International audienceBACKGROUND: Action potentials are the classic mechanism by which neurons convey a state of excitation throughout their length, leading, after synaptic transmission, to the activation of other neurons and consequently to network functioning. Using an in vitro integrated model, we found previously that peripheral networks in the autonomic nervous system can organise an unconventional regulatory reflex of the digestive tract motility without action potentials. METHODOLOGY/PRINCIPAL FINDINGS: In this report, we used combined neuropharmacological and biochemical approaches to elucidate some steps of the mechanism that conveys excitation along the nerves fibres without action potentials. This mechanism requires the production of ceramide in membrane lipid rafts, which triggers in the cytoplasm an increase in intracellular calcium concentration, followed by activation of a neuronal nitric oxide synthase leading to local production of nitric oxide, and then to guanosine cyclic monophosphate. This sequence of second messengers is activated in cascade from rafts to rafts to ensure conduction of the excitation along the nerve fibres. CONCLUSIONS/SIGNIFICANCE: Our results indicate that second messengers are involved in neuronal conduction of excitation without action potentials. This mechanism represents the first evidence-to our knowledge-that excitation is carried along nerves independently of electrical signals. This unexpected ceramide-based conduction of excitation without action potentials along the autonomic nerve fibres opens up new prospects in our understanding of neuronal functioning

Structure-In Vitro Activity Relationships of Pentamidine Analogues and Dication-Substituted Bis-Benzimidazoles as New Antifungal Agents

Twenty analogues of pentamidine, 7 primary metabolites of pentamidine, and 30 dicationic substituted bis-benzimidazoles were screened for their inhibitory and fungicidal activities against Candida albicans and Cryptococcus neoformans. A majority of the compounds had MICs at which 80% of the strains were inhibited (MIC80s) comparable to those of amphotericin B and fluconazole. Unlike fluconazole, many of these compounds were found to have potent fungicidal activity. The most potent compound against C. albicans had an MIC80 of ≤0.09 μg/ml, and the most potent compound against C. neoformans had an MIC80 of 0.19 μg/ml. Selected compounds were also found to be active against Aspergillus fumigatus, Fusarium solani, Candida species other than C. albicans, and fluconazole-resistant strains of C. albicans and C. neoformans. It is clear from the data presented here that further studies on the structure-activity relationships, mechanisms of action and toxicities, and in vivo efficacies of these compounds are warranted to determine their clinical potential

Sex Steroids Induce Membrane Stress Responses and Virulence Properties in Pseudomonas aeruginosa.

Estrogen, a major female sex steroid hormone, has been shown to promote the selection of mucoid Pseudomonas aeruginosa in the airways of patients with chronic respiratory diseases, including cystic fibrosis. This results in long-term persistence, poorer clinical outcomes, and limited therapeutic options. In this study, we demonstrate that at physiological concentrations, sex steroids, including testosterone and estriol, induce membrane stress responses in P. aeruginosa This is characterized by increased virulence and consequent inflammation and release of proinflammatory outer membrane vesicles promoting in vivo persistence of the bacteria. The steroid-induced P. aeruginosa response correlates with the molecular polarity of the hormones and membrane fluidic properties of the bacteria. This novel mechanism of interaction between sex steroids and P. aeruginosa explicates the reported increased disease severity observed in females with cystic fibrosis and provides evidence for the therapeutic potential of the modulation of sex steroids to achieve better clinical outcomes in patients with hormone-responsive strains.IMPORTANCE Molecular mechanisms by which sex steroids interact with P. aeruginosa to modulate its virulence have yet to be reported. Our work provides the first characterization of a steroid-induced membrane stress mechanism promoting P. aeruginosa virulence, which includes the release of proinflammatory outer membrane vesicles, resulting in inflammation, host tissue damage, and reduced bacterial clearance. We further demonstrate that at nanomolar (physiological) concentrations, male and female sex steroids promote virulence in clinical strains of P. aeruginosa based on their dynamic membrane fluidic properties. This work provides, for the first-time, mechanistic insight to better understand and predict the P. aeruginosa related response to sex steroids and explain the interindividual patient variability observed in respiratory diseases such as cystic fibrosis that are complicated by gender differences and chronic P. aeruginosa infection

Smart Antennas and Front-End Modules in Q-band for Backhaul Networks

[EN] As mobile operators face increasing density of base stations as well as growing bandwidth requirements, mobile backhaul has become the new challenge. This article defines the architecture for future mobile backhaul networks as proposed in the framework of the FP7 EU SARABAND project. This solution exploits a new and wider frequency spectrum band, the Q-band (40.5 43.5 GHz), to provide massive amounts of capacity. However, for the full deployment of such backhaul networks, new technology development in the Q-band must be addressed. In particular, this article gives an overview of the disruptive technology on antennas and front-end modules developed within this project.Vilar Mateo, R.; Martí Sendra, J.; Czarny, R.; Sypek, M.; Makowski, M.; Martel, C.; Crepin, T.... (2014). Smart Antennas and Front-End Modules in Q-band for Backhaul Networks. Microwave Journal. S:28-34. http://hdl.handle.net/10251/52765S2834

Induced topological changes in DNA complexes: influence of DNA sequences and small molecule structures

Heterocyclic diamidines are compounds with antiparasitic properties that target the minor groove of kinetoplast DNA. The mechanism of action of these compounds is unknown, but topological changes to DNA structures are likely to be involved. In this study, we have developed a polyacrylamide gel electrophoresis-based screening method to determine topological effects of heterocyclic diamidines on four minor groove target sequences: AAAAA, TTTAA, AAATT and ATATA. The AAAAA and AAATT sequences have the largest intrinsic bend, whereas the TTTAA and ATATA sequences are relatively straight. The changes caused by binding of the compounds are sequence dependent, but generally the topological effects on AAAAA and AAATT are similar as are the effects on TTTAA and ATATA. A total of 13 compounds with a variety of structural differences were evaluated for topological changes to DNA. All compounds decrease the mobility of the ATATA sequence that is consistent with decreased minor groove width and bending of the relatively straight DNA into the minor groove. Similar, but generally smaller, effects are seen with TTTAA. The intrinsically bent AAAAA and AAATT sequences, which have more narrow minor grooves, have smaller mobility changes on binding that are consistent with increased or decreased bending depending on compound structure

Antihypertensive Treatment Differentially Affects Vascular Sphingolipid Biology in Spontaneously Hypertensive Rats

We have previously shown that essential hypertension in humans and spontaneously hypertensive rats (SHR), is associated with increased levels of ceramide and marked alterations in sphingolipid biology. Pharmacological elevation of ceramide in isolated carotid arteries of SHR leads to vasoconstriction via a calcium-independent phospholipase A2, cyclooxygenase-1 and thromboxane synthase-dependent release of thromboxane A2. This phenomenon is almost absent in vessels from normotensive Wistar Kyoto (WKY) rats. Here we investigated whether lowering of blood pressure can reverse elevated ceramide levels and reduce ceramide-mediated contractions in SHR. Methods and Findings For this purpose SHR were treated for 4 weeks with the angiotensin II type 1 receptor antagonist losartan or the vasodilator hydralazine. Both drugs decreased blood pressure equally (SBP untreated SHR: 191±7 mmHg, losartan: 125±5 mmHg and hydralazine: 113±14 mmHg). The blood pressure lowering was associated with a 20–25% reduction in vascular ceramide levels and improved endothelial function of isolated carotid arteries in both groups. Interestingly, losartan, but not hydralazine treatment, markedly reduced sphingomyelinase-induced contractions. While both drugs lowered cyclooxygenase-1 expression, only losartan and not hydralazine, reduced the endothelial expression of calcium-independent phospholipase A2. The latter finding may explain the effect of losartan treatment on sphingomyelinase-induced vascular contraction. Conclusion In summary, this study corroborates the importance of sphingolipid biology in blood pressure control and specifically shows that blood pressure lowering reduces vascular ceramide levels in SHR and that losartan treatment, but not blood pressure lowering per se, reduces ceramide-mediated arterial contractions