Ultrasonic absorption studies of poly-benzyl-L-aspartate in mixed solvents, in relation to the helix-cell transition

Ultrasonic absorption measurements were carried out on solutions of polybenzyl-L -aspartate (PBLA) in chloroform–dichloroacetic acid (DCA) and in 1,2-dichloroethane (DCE)–DCA, in the range 3.9–155 MHZ . The helix–coil transition of PBLA produces an increase of absorption which is larger in CHCl₃–DCA than in DCE–DCA solutions. The influence of the solvent on the excess ultrasonic absorption suggests that solvation processes may be involved in these changes of absorption. The plots of the absorption vs. the volume fraction of DCA do not show any absorption maximum. This indicates that the ultrasonic absorption is not sensitive to the helix–coil equilibrium of PBLA in the frequency range investigated. A maximum value of 10⁹ S ^?1 has been obtained for the rate constant of growth of a helix region.     

Expression of Enterocin-P in HEK Platform: Evaluation of Its Cytotoxic Effects on Cancer Cell Lines and Its Potency to Interact with Cell-Surface Glycosaminoglycan by Molecular Modeling

International Journal of Peptide Research and Therapeutics - Cancer remains one of the leading causes of death worldwide. Introduction of natural compounds with anticancer properties can be an...     

Composition and Intraspecific Chemical Variability of Leaf Essential Oil of Laggera pterodonta from Côte d'Ivoire

The chemical composition of 44 leaf oil samples of Laggera pterodonta (DC.) Sch.Bip. ex Oliv. (Asteraceae) from Côte d'Ivoire was investigated, using combination of chromatographic (GC‐FID) and spectroscopic (GC/MS, ¹³C‐NMR) techniques. Two oil samples chosen according to their chromatographic profiles were submitted to column chromatography and all fractions of CC were analyzed by GC‐FID, GC/MS and ¹³C‐NMR. In total, 83 components accounting for 96.5 to 99.4 % of the whole chemical composition were identified. Significant variations were observed within terpene classes: monoterpene hydrocarbons (0.4–22.7 %), oxygenated monoterpenes (32.9–54.9 %), sesquiterpene hydrocarbons (18.6–38.3 %) and oxygenated sesquiterpenes (3.5–38.4 %). Thus, the 44 compositions were subjected to hierarchical cluster analysis (HCA) and principal component analysis (PCA). Two groups were differentiated according to their composition. All the samples contained 2,5‐dimethoxy‐p‐cymene, α‐humulene and (E)‐β‐caryophyllene among the main components. Other components were present at appreciable contents and allowed differentiation of two groups: sabinene and germacrene D for Group I; 10‐epi‐γ‐eudesmol and eudesm‐7(11)‐en‐4α‐ol for Group II. All the samples collected in Eastern Côte d'Ivoire constituted Group I, while samples collected in the Central area of the country constituted Group II.     

‘Have you got the Britísh?’: narratives of migration and settlement among Albanian-origin immigrants in London

Studies on migration and integration in Britain have noted the paucity of research on ‘new’ migrants, especially ‘illegal’ migrants and asylum seekers. This paper focuses on one understudied group – Albanian immigrants and their children – and looks at their migration and settlement, based on sixty interviews conducted in two phases either side of a 2003 mini-amnesty that gave many indefinite leave to remain. This regularization is the fulcrum around which our analytical narrative is built. Focusing on the interaction of migrants' agency with host-country structure, the paper shows that an unsettled asylum policy and delays in implementation have had deleterious effects on migrants' integration and sense of belonging, even after citizenship acquisition. As they search for a social and ethnic positioning within a multi-ethnic host society, the eventual realization of Albanians' migration project is accompanied by culture shock, intergenerational difference and ambivalence towards integration.     

Alpha-Synuclein Induces Lysosomal Rupture and Cathepsin Dependent Reactive Oxygen Species Following Endocytosis

α-synuclein dysregulation is a critical aspect of Parkinson''s disease pathology. Recent studies have observed that α-synuclein aggregates are cytotoxic to cells in culture and that this toxicity can be spread between cells. However, the molecular mechanisms governing this cytotoxicity and spread are poorly characterized. Recent studies of viruses and bacteria, which achieve their cytoplasmic entry by rupturing intracellular vesicles, have utilized the redistribution of galectin proteins as a tool to measure vesicle rupture by these organisms. Using this approach, we demonstrate that α-synuclein aggregates can induce the rupture of lysosomes following their endocytosis in neuronal cell lines. This rupture can be induced by the addition of α-synuclein aggregates directly into cells as well as by cell-to-cell transfer of α-synuclein. We also observe that lysosomal rupture by α-synuclein induces a cathepsin B dependent increase in reactive oxygen species (ROS) in target cells. Finally, we observe that α-synuclein aggregates can induce inflammasome activation in THP-1 cells. Lysosomal rupture is known to induce mitochondrial dysfunction and inflammation, both of which are well established aspects of Parkinson''s disease, thus connecting these aspects of Parkinson''s disease to the propagation of α-synuclein pathology in cells.     

Synthesis, spectroscopic and X-ray characterization of a copper(II) complex with the Schiff base derived from pyridoxal and aminoguanidine: NMR spectral studies of the ligand

A copper(II) complex with the pyridoxal-aminoguanidine (PL-AG) Schiff base adduct, as an organic compound of the very potent biological activity and promising pharmacological importance in the treatment of diabetic complications, has been prepared and characterized. The X-ray structural analysis of the [CuCl2(PL-AG)] complex showed that it has a distorted pseudo-square-pyramidal (4+1) structure with the tridentate ONN Schiff base in the equatorial plane, with the Cu-O(1), Cu-N(1) and Cu-N(3) bond lengths of 1.917(2)A, 1.930(2)A and 1.984(2)A, respectively. The bond length of the equatorial Cu-Cl(1) is 2.279(1)A, while that of the apical Cu-Cl(2) is 2.792(1)A. Pyridoxal fragment is coordinated in its zwitterionic form. In addition to the X-ray structural analysis, the complex was characterized by IR spectrometric, conductometric and magnetic techniques, and the ligand itself by IR, 1H and 13C NMR spectra.     

Synthesis and antibacterial studies of binaphthyl-based tripeptoids. Part 1

An efficient synthesis of 29 new binaphthyl-based neutral, and mono- and di-cationic, peptoids is described. Some of these compounds had antibacterial activities with MIC values of 1.9–3.9 μg/mL against Staphylococcus aureus. One peptoid had a MIC value of 6 μg/mL against a methicillin-resistant strain of S. aureus (MRSA) and a MIC value of 2 μg/mL against vancomycin-resistant strains of enterococci (VRE).     

Thyroid hormones, cytokines, physical training and metabolic control.

During the acute training response, peripheral cellular mechanisms are mainly metabolostatic to achieve energy supply. During prolonged training, glycogen deficiency occurs; this is associated with increased expression of local cytokines, and decreased insulin secretion and beta-adrenergic stimulation and lipolysis in adipose tissue which looses energy. This is indicated by decrease of adipocyte hormone leptin, which has inhibitory effects on excitatory hypothalamic neurons. Leptin, insulin, and cytokines such as interleukin 6 (IL-6) contribute to the metabolic error signal to the hypothalamus which result in decrease of hypothalamic release hormones and sympathoadrenergic stimulation. Thyroid stimulating hormone (TSH) is correlated to the metabolic hormones leptin and insulin, and may be used as indicator of metabolic control. Because the hypothalamus integrates various error signals (metabolic, hormonal, sensory afferents, and central stimuli), the pituitary's releasing hormones represent the functional status of an athlete. Long-term overtraining will lead to downregulation of hypothalamic hormonal and sympathoadrenergic responses, catabolism, and fatigue. These changes contribute to myopathy with predominant expression of slow muscle fiber type and inadequacy in performance. Thyroid hormones are closely involved in the training response and metabolic control.     

Interaction between hydroxystilbamidine and DNA. II. Temperature jump relaxation study. Dynamics of nucleic acids and polynucleotides.

A temperature-jump relaxation study of the interaction of hydroxystilbamidine with DNA and synthetic polynucleotides has been performed. Two concentration dependent relaxation times tau1 and tau2 have been observed in the submillisecond range when detecting relaxation effects by means of light absorption. The longer of these two times (tau1) is also observed when using "blue" or "red" fluorescence detection. In the longer time scale the "red" fluorescence shows no other relaxation but the blue fluorescence shows two additional relaxation processes (tau3 and tau4) which correspond to an increase of fluorescence with temperature and which are independent of concentration. The experimental results clearly indicate that tau1 and tau2 are associated with the binding of the dye to strong and weak binding sites, respectively. A kinetic model is given to explain the results. It allows the determination of the four rate constants for the two binding reactions and yields equilibrium association constants in good agreement with those obtained from stoichiometric studies. The study of the effect of temperature, nature of the polymer, ionic strength and fraction of bound dye on tau3 and tau4 indicates that the dye acts only as a "blue" fluorescence probe of some processes involving the DNA or polynucleotide alone. These processes appear to be related with the dynamic structure of the polymers.