Effects of Ethanolic Extract of Cynara cardunculus (Artichoke) Leaves on Neuroinflammatory and Neurochemical Parameters in a Diet-Induced Mice Obesity Model

Neurochemical Research - This study aimed to evaluate the effect of Cynara cardunculus leaf ethanol extract on inflammatory and oxidative stress parameters in the hypothalamus, prefrontal cortex,...     

Genetic Analysis of Connective Tissue Growth Factor as an Effector of Transforming Growth Factor β Signaling and Cardiac Remodeling

The matricellular secreted protein connective tissue growth factor (CTGF) is upregulated in response to cardiac injury or with transforming growth factor β (TGF-β) stimulation, where it has been suggested to function as a fibrotic effector. Here we generated transgenic mice with inducible heart-specific CTGF overexpression, mice with heart-specific expression of an activated TGF-β mutant protein, mice with heart-specific deletion of Ctgf, and mice in which Ctgf was also deleted from fibroblasts in the heart. Remarkably, neither gain nor loss of CTGF in the heart affected cardiac pathology and propensity toward early lethality due to TGF-β overactivation in the heart. Also, neither heart-specific Ctgf deletion nor CTGF overexpression altered cardiac remodeling and function with aging or after multiple acute stress stimuli. Cardiac fibrosis was also unchanged by modulation of CTGF levels in the heart with aging, pressure overload, agonist infusion, or TGF-β overexpression. However, CTGF mildly altered the overall cardiac response to TGF-β when pressure overload stimulation was applied. CTGF has been proposed to function as a critical TGF-β effector in underlying tissue remodeling and fibrosis throughout the body, although our results suggest that CTGF is of minimal importance and is an unlikely therapeutic vantage point for the heart.     

Determination of hepatitis delta virus ribozyme N(–1) nucleobase and functional group specificity using internal competition kinetics

Biological catalysis involves interactions distant from the site of chemistry that can position the substrate for reaction. Catalysis of RNA 2′-O-transphosphorylation by the hepatitis delta virus (HDV) ribozyme is sensitive to the identity of the N(–1) nucleotide flanking the reactive phosphoryl group. However, the interactions that affect the conformation of this position, and in turn the 2′O nucleophile, are unclear. Here, we describe the application of multiple substrate internal competition kinetic analyses to understand how the N(–1) nucleobase contributes to HDV catalysis and test the utility of this approach for RNA structure–function studies. Internal competition reactions containing all four substrate sequence variants at the N(–1) position in reactions using ribozyme active site mutations at A77 and A78 were used to test a proposed base-pairing interaction. Mutants A78U, A78G, and A79G retain significant catalytic activity but do not alter the specificity for the N(–1) nucleobase. Effects of nucleobase analog substitutions at N(–1) indicate that U is preferred due to the ability to donate an H-bond in the Watson–Crick face and avoid minor groove steric clash. The results provide information essential for evaluating models of the HDV active site and illustrate multiple substrate kinetic analyses as a practical approach for characterizing structure–function relationships in RNA reactions.     

Purification and some properties of an extracellular acid protease from <Emphasis Type="Italic">Aspergillus</Emphasis><Emphasis Type="Italic">clavatus</Emphasis>

Acid proteases represent an important group of enzymes, widely used in food, beverage and pharmaceutical industries. For most of these applications the enzymatic preparation must be at least partially purified and free of substances that could change the characteristics of the product or the process. Fungal proteases have replaced other sources because they are easily obtained mainly from Mucor, Rhizopus, Penicillium and Aspergillus species. A strain of Aspergillus clavatus was selected by producing high level of acid protease activity. An extracellular aspartatic protease from this strain was purified 37.2 times with 37% recovery using (NH₄)₂SO₄ fractionation and ion-exchange chromatography. The enzyme was found to be monomeric having a molecular mass of 30.4 kDa. The purified enzyme is an acid protease with optimum pH of 5.5 and temperature for optimum activity of 50 °C. Its high pH stability was verified in the range of 3.5–6.5. The acid protease was strongly inhibited by Hg⁺² and partially inhibited by Cu⁺², Zn⁺² and Mn⁺². The enzyme was sensitive to denaturing agent SDS and activated by thiol-containing reducing agent dithiotreitol (DTT). The protease activity was not influenced by iodoacetic acid, E-64 and PMSF, while it was lightly actived by EDTA and totally inhibited by pepstatin, with a K_i of 7.8 μM, indicating that is an aspartic protease. A. clavatus acid protease presents interesting characteristics for biotechnological process, such as cheese and flavor manufacture and dietary supplements, in which activity and stability in acid pH are required.     

AXY8 encodes an α-fucosidase, underscoring the importance of apoplastic metabolism on the fine structure of Arabidopsis cell wall polysaccharides

An Arabidopsis thaliana mutant with an altered structure of its hemicellulose xyloglucan (XyG; axy-8) identified by a forward genetic screen facilitating oligosaccharide mass profiling was characterized. axy8 exhibits increased XyG fucosylation and the occurrence of XyG fragments not present in the wild-type plant. AXY8 was identified to encode an α-fucosidase acting on XyG that was previously designated FUC95A. Green fluorescent protein fusion localization studies and analysis of nascent XyG in microsomal preparations demonstrated that this glycosylhydrolase acts mainly on XyG in the apoplast. Detailed structural analysis of XyG in axy8 gave unique insights into the role of the fucosidase in XyG metabolism in vivo. The genetic evidence indicates that the activity of glycosylhydrolases in the apoplast plays a major role in generating the heterogeneity of XyG side chains in the wall. Furthermore, without the dominant apoplastic glycosylhydrolases, the XyG structure in the wall is mainly composed of XXXG and XXFG subunits.     

The nature and perception of fluctuations in human musical rhythms

Although human musical performances represent one of the most valuable achievements of mankind, the best musicians perform imperfectly. Musical rhythms are not entirely accurate and thus inevitably deviate from the ideal beat pattern. Nevertheless, computer generated perfect beat patterns are frequently devalued by listeners due to a perceived lack of human touch. Professional audio editing software therefore offers a humanizing feature which artificially generates rhythmic fluctuations. However, the built-in humanizing units are essentially random number generators producing only simple uncorrelated fluctuations. Here, for the first time, we establish long-range fluctuations as an inevitable natural companion of both simple and complex human rhythmic performances. Moreover, we demonstrate that listeners strongly prefer long-range correlated fluctuations in musical rhythms. Thus, the favorable fluctuation type for humanizing interbeat intervals coincides with the one generically inherent in human musical performances.