A Combination Supplement of Fructo- and Xylo-Oligosaccharides Significantly Abrogates Oxidative Impairments and Neurotoxicity in Maternal/Fetal Milieu Following Gestational Exposure to Acrylamide in Rat

Neurochemical Research - Prebiotic oligosaccharides are demonstrated to confer a wide spectrum of physiological benefits during pregnancy. In view of this, focused attempts are being directed...     

Comparison of label-free and GFP multiphoton imaging of hair follicle-associated pluripotent (HAP) stem cells in mouse whiskers

Hair-follicle-associated pluripotent (HAP) stem cells can differentiate into many cell types, including neurons and heart muscle cells, and have been shown to repair peripheral nerves and the spinal cord in mice. HAP stem cells can be obtained from each individual patient for regenerative medicine which overcomes problems with immune rejection. Previously, we have demonstrated that genetically-encoded protein markers such as GFP in transgenic mice can be used to visualize HAP stem cells in vivo by multiphoton tomography. Detection and visualization of stem cells in vivo without exogenous labels such as GFP would be important for human application. In the present report, we demonstrate label-free visualization of hair follicle stem cells in mouse whiskers by multiphoton tomography due to the intrinsic fluorophores such as NAD(P)H/flavins. We compared multiphoton tomography of GFP-labeled HAP stem cells and unlabeled stem cells in isolated mouse whiskers. We show that observation of HAP stem cells by label-free multiphoton tomography is comparable to detection using GFP-labeled stem cells. The results described here have important implications for detection and isolation of human HAP stem cells for regenerative medicine.     

Better to Be in Bad Company than to Be Alone? Aedes Vectors Respond Differently to Breeding Site Quality in the Presence of Others

This study focuses on two competing species, Aedes aegypti and Aedes albopictus (Diptera: Culicidae), both invasive mosquitoes of the New World. Context-specific competition between immature forms inside containers seems to be an important determinant of the coexistence or displacement of each species in different regions of the world. Here, competition experiments developed at low density (one, two or three larvae) and receiving four different resource food concentration, were designed to test whether Ae. albopictus and Ae. aegypti respond differently to competition, and whether competition can be attributed to a simple division of resources. Three phenotypic traits - larval development, adult survival under starvation and wing length - were used as indicators of performance. Larvae of neither species were limited by resource concentration when they were alone, unlike when they developed with competitors. The presence of conspecifics affected Ae. aegypti and Ae. albopictus, inducing slower development, reduced survival and wing length. The response to resource limitation was different when developing with heterospecifics: Ae. aegypti developing with one heterospecific showed faster development, producing smaller adults with shorter lives, while in the presence of two competitors, development increased and adults lived longer. Aedes albopictus demonstrated a better performance when developing with heterospecifics, with no loss in their development period and improved adult survival. Overall, our results suggest that response to competition can not simply be attributed to the division of resources, and that larvae of both species presented large phenotypic plasticity in their response to the presence or absence of heterospecifics and conspecifics.     

The Influence of Arginine on the Response of Enamel Matrix Derivative (EMD) Proteins to Thermal Stress: Towards Improving the Stability of EMD-Based Products

In a current procedure for periodontal tissue regeneration, enamel matrix derivative (EMD), which is the active component, is mixed with a propylene glycol alginate (PGA) gel carrier and applied directly to the periodontal defect. Exposure of EMD to physiological conditions then causes it to precipitate. However, environmental changes during manufacture and storage may result in modifications to the conformation of the EMD proteins, and eventually premature phase separation of the gel and a loss in therapeutic effectiveness. The present work relates to efforts to improve the stability of EMD-based formulations such as Emdogain^™ through the incorporation of arginine, a well-known protein stabilizer, but one that to our knowledge has not so far been considered for this purpose. Representative EMD-buffer solutions with and without arginine were analyzed by 3D-dynamic light scattering, UV-Vis spectroscopy, transmission electron microscopy and Fourier transform infrared spectroscopy at different acidic pH and temperatures, T, in order to simulate the effect of pH variations and thermal stress during manufacture and storage. The results provided evidence that arginine may indeed stabilize EMD against irreversible aggregation with respect to variations in pH and T under these conditions. Moreover, stopped-flow transmittance measurements indicated arginine addition not to suppress precipitation of EMD from either the buffers or the PGA gel carrier when the pH was raised to 7, a fundamental requirement for dental applications.     

Historical demographic profiles and genetic variation of the East African Butana and Kenana indigenous dairy zebu cattle

Butana and Kenana breeds from Sudan are part of the East African zebu Bos indicus type of cattle. Unlike other indigenous zebu cattle in Africa, they are unique due to their reputation for high milk production and are regarded as dairy cattle, the only ones of their kind on the African continent. In this study, we sequenced the complete mitochondrial DNA (mtDNA) D‐loop of 70 animals to understand the maternal genetic variation, demographic profiles and history of the two breeds in relation to the history of cattle pastoralism on the African continent. Only taurine mtDNA sequences were identified. We found very high mtDNA diversity but low level of maternal genetic structure within and between the two breeds. Bayesian coalescent‐based analysis revealed different historical and demographic profiles for the two breeds, with an earlier population expansion in the Butana vis a vis the Kenana. The maternal ancestral populations of the two breeds may have diverged prior to their introduction into the African continent, with first the arrival of the ancestral Butana population. We also reveal distinct demographic history between the two breeds with the Butana showing a decline in its effective population size (N_e) in the recent past ~590 years. Our results provide new insights on the early history of cattle pastoralism in Sudan indicative of a large ancient effective population size.     

Protein stability and conformational rearrangements in lipid bilayers: linear gramicidin, a model system.

The replacement of four tryptophans in gramicidin A by four phenylalanines (gramicidin M) causes no change in the molecular fold of this dimeric peptide in a low dielectric isotropic organic solvent, but the molecular folds are dramatically different in a lipid bilayer environment. The indoles of gramicidin A interact with the anisotropic bilayer environment to induce a change in the molecular fold. The double-helical fold of gramicidin M, as opposed to the single-stranded structure of gramicidin A, is not compatible with ion conductance. Gramicidin A/gramicidin M hybrid structures have also been prepared, and like gramicidin M homodimers, these dimeric hybrids appear to have a double-helical fold, suggesting that a couple of indoles are being buried in the bilayer interstices. To achieve this equilibrium structure (i.e., minimum energy conformation), incubation at 68 degrees C for 2 days is required. Kinetically trapped metastable structures may be more common in lipid bilayers than in an aqueous isotropic environment. Structural characterizations in the bilayers were achieved with solid-state NMR-derived orientational constraints from uniformly aligned lipid bilayer samples, and characterizations in organic solvents were accomplished by solution NMR.