Cx43 Promotes Endothelial Cell Migration and Angiogenesis via the Tyrosine Phosphatase SHP-2

The gap junction protein connexin 43 (Cx43) is associated with increased cell migration and to related changes of the actin cytoskeleton, which is mediated via its C-terminal cytoplasmic tail and is independent of its channel function. Cx43 has been shown to possess an angiogenic potential, however, the role of Cx43 in endothelial cell migration has not yet been investigated. Here, we found that the knock-down of Cx43 by siRNA in human microvascular endothelial cells (HMEC) reduces migration, as assessed by a wound assay in vitro and impaired aortic vessel sprouting ex vivo. Immunoprecipitation of Cx43 revealed an interaction with the tyrosine phosphatase SHP-2, which enhanced its phosphatase activity, as observed in Cx43 expressing HeLa cells compared to cells treated with an empty vector. Interestingly, the expression of a dominant negative substrate trapping mutant SHP-2 (CS) in HMEC, via lentiviral transduction, also impaired endothelial migration to a similar extent as Cx43 siRNA compared to SHP-2 WT. Moreover, the reduction in endothelial migration upon Cx43 siRNA could not be rescued by the introduction of a constitutively active SHP-2 construct (EA). Our data demonstrate that Cx43 and SHP-2 mediate endothelial cell migration, revealing a novel interaction between Cx43 and SHP-2, which is essential for this process.     

Starch-Derived Products for Detergents

Recent developments in the formulation of detergents have been driven by a strong consumer demand for natural and biodegradable products. Detergent manufacturers responded to this demand with corresponding products and advertising slogans such as “fully biodegradable”, “natural” or even “double natural” to oust their competitors. In a detergent formulation, starch- derived products can in principle be used for the following purposes: as the hydrophilic head group in surfactants, as the starting material for (poly)carboxylate co-builders and as the backbone of bleaching activators. Non-ionic classical surfactants can be replaced by alkylpolyglucosides (APGs), a class of products completely based on renewable resources such as glucose and fatty alcohols derived from natural fatty acids. Sodium tripolyphosphate (STPP), the product responsible for the eutrophication of surface waters, can be substituted by a combination of an inorganic zeolite and highly oxidised starch (dicarboxylic starch) or by citrate. Acetylated polyols derived from hydrogenated carbohydrates such as sorbitol can take over the function of the petrochemically-based tetraacetyl ethylene diamine (TAED) used as activator to allow perborate bleaching at lower washing temperatures.     

Effect of radiographic positioning on interpretation of cubital joint congruity in dogs

OBJECTIVE: To ascertain effects of x-ray beam centering and limb position on apparent congruity of a normal cubital joint (elbow). ANIMALS: 6 skeletally mature male Treeing Walker Coonhounds without physical, radiographic, or gross evidence of elbow abnormalities. PROCEDURE: Relative movement among humerus, radius, and ulna and measured joint space width on mediolateral and craniocaudal radiographic views was compared, using various x-ray beam centering and limb positions. RESULTS: Highest agreement and greatest certainty on subjective determination of congruity was for the flexed 90 degrees mediolateral radiographic view with the x-ray beam centered on the elbow. Distortion artifact of the proximal ulnar measurements was significant when the x-ray beam was centered on the midpoint of the radius. On the mediolateral view, the humeroradial joint space became significantly wide when the elbow was flexed. On the craniocaudal view, maximal humeroradial joint space width was obtained when the x-ray beam bisected the angle of the joint or was angled +30 degrees toward the humerus. CONCLUSIONS: Artifact distortion of joint width affected objective and subjective assessment of elbow congruity when the limb was placed in extreme flexion or extension or when the x-ray beam was not centered over the area of interest. Optimal visualization of the humeroradial joint space on the craniocaudal view was achieved when the x-ray beam bisected the angle of the elbow or was slightly angled toward the humerus. CLINICAL RELEVANCE: Elbow congruity was best assessed on the flexed 90 degrees lateral radiographic view with the x-ray beam centered on the joint.     

Hypoxia-ischemia induces a rapid elevation of ubiquitin conjugate levels and ubiquitin immunoreactivity in the immature rat brain

Postnatal rats at 7 and 21 days of age were subjected to unilateral hypoxia-ischemia (H/I) by right carotid artery ligation followed by 1.5 to 2 hours of hypoxia (8% oxygen). Brains were frozen at specific intervals of recovery from 0 to 24 hours. Western blots of samples of right and left forebrain were immunodeveloped with a monoclonal antibody specific for ubiquitin, RHUb1. An elevation of ubiquitin conjugate levels in the right compared with the left forebrain of 7-day-old animals was detectable immediately following H/I and increased by close to 60% of control level within 1 hour of recovery. The conjugate immunoreactivity remained at this level for 6 hours but had declined to control levels by 24 hours of recovery. No such increase was observed in response to hypoxia alone. Similar changes were observed in samples from the 21-day-old rat brain. However, the elevation of ubiquitin conjugate levels was of slower onset and persisted longer than observed for the 7-day-old animals. Immunocytochemical studies of brain fixed by immersion in formaldehyde/acetone/methanol showed that ubiquitin-like immunoreactivity was increased in the right, but not left, cerebral cortex and hippocampus of animals subjected to H/I. The data suggest that elevated ubiquitination may represent a neuroprotective response to H/I.     

Classification of Amyloidosis by Model-Assisted Mass Spectrometry-Based Proteomics

Amyloidosis is a rare disease caused by the misfolding and extracellular aggregation of proteins as insoluble fibrillary deposits localized either in specific organs or systemically throughout the body. The organ targeted and the disease progression and outcome is highly dependent on the specific fibril-forming protein, and its accurate identification is essential to the choice of treatment. Mass spectrometry-based proteomics has become the method of choice for the identification of the amyloidogenic protein. Regrettably, this identification relies on manual and subjective interpretation of mass spectrometry data by an expert, which is undesirable and may bias diagnosis. To circumvent this, we developed a statistical model-assisted method for the unbiased identification of amyloid-containing biopsies and amyloidosis subtyping. Based on data from mass spectrometric analysis of amyloid-containing biopsies and corresponding controls. A Boruta method applied on a random forest classifier was applied to proteomics data obtained from the mass spectrometric analysis of 75 laser dissected Congo Red positive amyloid-containing biopsies and 78 Congo Red negative biopsies to identify novel “amyloid signature” proteins that included clusterin, fibulin-1, vitronectin complement component C9 and also three collagen proteins, as well as the well-known amyloid signature proteins apolipoprotein E, apolipoprotein A4, and serum amyloid P. A SVM learning algorithm were trained on the mass spectrometry data from the analysis of the 75 amyloid-containing biopsies and 78 amyloid-negative control biopsies. The trained algorithm performed superior in the discrimination of amyloid-containing biopsies from controls, with an accuracy of 1.0 when applied to a blinded mass spectrometry validation data set of 103 prospectively collected amyloid-containing biopsies. Moreover, our method successfully classified amyloidosis patients according to the subtype in 102 out of 103 blinded cases. Collectively, our model-assisted approach identified novel amyloid-associated proteins and demonstrated the use of mass spectrometry-based data in clinical diagnostics of disease by the unbiased and reliable model-assisted classification of amyloid deposits and of the specific amyloid subtype.     

From Molecular Clusters to Metal Nanoparticles

Different methods to prepare supported metal nanoparticles of uniform size are discussed. (i) Supported ruthenium particles were generated from Ru and Ru-Fe bimetallic molecular metal carbonyl cluster precursors (MCC). (ii) Gold nanoparticle formation in the supercage of Y zeolite was studied on Au/NaY, Au/HY and Au-Fe/HY system. (iii) Palladium nanoparticles were grown in liquid phase then deposited on an SiO₂ support or they were grown on the support surface in a solid-liquid interfacial layer. The particle size control was more efficient in the latter two cases than in the preparation starting from MCC.     

Reversible electrochemical insertion of anions in poly-p-phenylene from aqueous electrolytes

Poly-p-phenylene (PPP) was synthesized from benzene according to the Kovacic method. Electrodes were made from this electronic insulator by cold- or hot-pressing of the loose, brown powder, under the addition of 7.5 wt. % soot (Corax L^®, Degussa AG). The electrochemical insertion and removal of anions HSO⁻₄, ClO⁻₄ in this material in aqueous solutions of the corresponding acids was investigated by slow cyclic voltammetry.

Initially, only a surface layer of about 0.1 mm thickness takes part in the electrochemical processes, which are reversible. A maximum concentration of anions in the solid of [(−C₆H₄−)⁺₇ A⁻] is attainable. The maximum degree of insertion is equal to 0.14. The insertion potential U_I shifts strongly into the negative direction with increasing concentration c of the acid. A linear U_I/c relationship is observed as in the case of graphite, where the intercalation potential is more positive by 20–200 mV for the same electrolyte. The round trip current efficiency for the insertion/removal cycle increases with increasing acid concentration attaining 100% in 14 M H₂SO₄ or 11.3 M CHlO₄. For a given concentration, increases in the same order as with graphite (H₂SO₄ < HClO₄ < HBF₄), being somewhat lower for a given electrolyte composition. From anodic current limitation (j_lim = 5–10 mA cm⁻²), a diffusion coefficient of about D = 2 × 10⁻⁷ cm² s⁻¹ is derived for the transport of anions in the bulk of PPP. The striking similarity of our results to former findings with graphite is thoroughly discussed. Some general conclusions are derived thereof.     

Molecular Mechanisms of Taste Recognition: Considerations about the Role of Saliva

The gustatory system plays a critical role in determining food preferences and food intake, in addition to nutritive, energy and electrolyte balance. Fine tuning of the gustatory system is also crucial in this respect. The exact mechanisms that fine tune taste sensitivity are as of yet poorly defined, but it is clear that various effects of saliva on taste recognition are also involved. Specifically those metabolic polypeptides present in the saliva that were classically considered to be gut and appetite hormones (i.e., leptin, ghrelin, insulin, neuropeptide Y, peptide YY) were considered to play a pivotal role. Besides these, data clearly indicate the major role of several other salivary proteins, such as salivary carbonic anhydrase (gustin), proline-rich proteins, cystatins, alpha-amylases, histatins, salivary albumin and mucins. Other proteins like glucagon-like peptide-1, salivary immunoglobulin-A, zinc-α-2-glycoprotein, salivary lactoperoxidase, salivary prolactin-inducible protein and salivary molecular chaperone HSP70/HSPAs were also expected to play an important role. Furthermore, factors including salivary flow rate, buffer capacity and ionic composition of saliva should also be considered. In this paper, the current state of research related to the above and the overall emerging field of taste-related salivary research alongside basic principles of taste perception is reviewed.