Application of the dual-cell coulometric detector: a method for assaying monoamines and their metabolites

A new HPLC assay technique for monoamines and their metabolites, using a controlled potential coulometric detector equipped with a dual working electrode cell of fully porous graphite through which the samples flow, is described in comparison with a classical amperometric detector equipped with a glassy carbon electrode. Different potentials can be applied at each cell of the coulometric detector to improve sample resolution and detection sensitivity. The signal-to-noise ratio (s/n) calculated in similar conditions was 10 times lower for the coulometric detector than for the amperometric one. The dual-coulometric detector does not undergo daily decay or variation, and needs no particular care or preparation. It is therefore possible to achieve stable routine sensitivity in a range of 10 fmol. This new technique has been applied for assaying monoamines and their precursors and metabolites by direct injection of clear supernatant after centrifugation and for determination of catecholamine turnover in rat pineal gland and neuro- and adenohypophysis in samples purified by Al2O3 adsorption.     

Biological effects of low-level,very low-frequency (VLF) electric fields on the blood sedimentation rate

Experiments were performed to detect a possible effect on in vitro irradiated human blood samples. The erythrocyte sedimentation rate (ESR) and the bioimpedence of both treated with a low-level 1.59 kHz electrical field and untreated blood samples were measured. A statistically significant difference (P < 0.001) was found in the blood sedimentation rates between Controls and those exposed to VLF-field condition. The most striking result was that for a 20% of the blood samples analyzed under the influence of the VLF-field, the ESR tests were almost stopped by the latter, i.e. the blood sedimentation did not occur. Bioimpedance value of stopped blood samples were one order of magnitude lower than those of unirradiated samples.     

2,3-Butanediol production by Enterobacter aerogenes: selection of the optimal conditions and application to food industry residues

Optimum values of temperature, pH, and starting substrate concentration are experimentally determined for 2,3-butanediol production by Enterobacter aerogenes through three set of batch fermentations of synthetic glucose solutions. The results of tests carried out at variable temperature show an optimum of 39 °C and are used to estimate, for both fermentation and thermal inactivation, the activation enthalpies (7.19 and 23.6 kJ mol^у) and the related entropies (т.32 and т.27 kJ mol^у K^у). An optimum pH value of 6.0 is evidenced from batch runs at variable pH, whose results are also used to make reasonable hypotheses on the reaction controlling the metabolic pathway which leads to butanediol. The fermentability of different food industry wastes, namely starch hydrolysate, both raw and decoloured molasses, and whey, is finally checked.     

Rosuvastatin protects isolated hearts against ischemia-reperfusion injury: role of Akt-GSK-3β, metabolic environment,and mitochondrial permeability transition pore

Journal of Physiology and Biochemistry - The cardioprotective activity of rosuvastatin (R) is yet to be known. The objective of this study was to research whether R perfusion before global ischemia...     

Forty Years in the Making: Understanding the Molecular Mechanism of Peptide Regulation in Bacterial Development

Signal transduction systems are influenced by positive and negative forces resulting in an output reflecting the sum of the opposing forces. The Rap family of regulatory protein modules control the output of two-component signal transduction systems through protein∶protein and protein∶peptide interactions. These modules and their peptide regulators are found in complex signaling pathways, including the bacterial developmental pathway to sporulation, competence, and protease secretion. Two articles published in the current issue of PLOS Biology reveal by means of crystallographic analyses how the Rap proteins of bacilli are regulated by their inhibitor Phr peptide and provide a mechanistic explanation for a genetic phenotype isolated decades earlier. The Rap-Phr module of bacterial regulators was the prototype of a family that now extends to other bacterial signaling proteins that involve the use of the tetratricopeptide repeat structural fold. The results invite speculation regarding the potential exploitation of this module as a molecular tool for applications in therapeutic design and biotechnology.Cell signaling by oligopeptides is a critical component of the biology of eukaryotic and prokaryotic cells. In microorganisms such as Gram-positive bacteria, small peptides have been found to regulate a variety of cellular functions, providing the bacteria with the ability to communicate and change behavior of the same or of other species in response to conditions and perturbations of the environment [1]. Studies in the spore-forming model organism Bacillus subtilis were among the first to identify pathways in which peptide signaling played a regulatory role.     

Inside the “African Cattle Complex”: Animal Burials in the Holocene Central Sahara

Cattle pastoralism is an important trait of African cultures. Ethnographic studies describe the central role played by domestic cattle within many societies, highlighting its social and ideological value well beyond its mere function as ‘walking larder’. Historical depth of this African legacy has been repeatedly assessed in an archaeological perspective, mostly emphasizing a continental vision. Nevertheless, in-depth site-specific studies, with a few exceptions, are lacking. Despite the long tradition of a multi-disciplinary approach to the analysis of pastoral systems in Africa, rarely do early and middle Holocene archaeological contexts feature in the same area the combination of settlement, ceremonial and rock art features so as to be multi-dimensionally explored: the Messak plateau in the Libyan central Sahara represents an outstanding exception. Known for its rich Pleistocene occupation and abundant Holocene rock art, the region, through our research, has also shown to preserve the material evidence of a complex ritual dated to the Middle Pastoral (6080–5120 BP or 5200–3800 BC). This was centred on the frequent deposition in stone monuments of disarticulated animal remains, mostly cattle. Animal burials are known also from other African contexts, but regional extent of the phenomenon, state of preservation of monuments, and associated rock art make the Messak case unique. GIS analysis, excavation data, radiocarbon dating, zooarchaeological and isotopic (Sr, C, O) analyses of animal remains, and botanical information are used to explore this highly formalized ritual and the lifeways of a pastoral community in the Holocene Sahara.     

Enhancing the evaluation of PI3K inhibitors through 3D melanoma models

Targeted therapies for mutant BRAF metastatic melanoma are effective but not curative due to acquisition of resistance. PI3K signaling is a common mediator of therapy resistance in melanoma; thus, the need for effective PI3K inhibitors is critical. However, testing PI3K inhibitors in adherent cultures is not always reflective of their potential in vivo. To emphasize this, we compared PI3K inhibitors of different specificity in two‐ and three‐dimensional (2D, 3D) melanoma models and show that drug response predictions gain from evaluation using 3D models. Our results in 3D demonstrate the anti‐invasive potential of PI3K inhibitors and that drugs such as PX‐866 have beneficial activity in physiological models alone and when combined with BRAF inhibition. These assays finally help highlight pathway effectors that could be involved in drug response in different environments (e.g. p4E‐BP1). Our findings show the advantages of 3D melanoma models to enhance our understanding of PI3K inhibitors.     

Effect of transport and competition on ligand binding

We present a model to describe the physics of chemoreception in processes determined by competitive ligand binding. Our model describes the competition between various populations, such as ligands vs. blockers and receptors vs. decoys, in protein activation when diffusion is rate-determining. Full spatio-temporal solutions can be obtained numerically. The model structure is kept simple enough as to permit its easy generalization to describe a large subset of the manifold of possible situations occurring in nature. The power and simplicity of the proposed method are exhibited through the solution of several examples which are discussed in detail.