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Biological Substrates (biological + substrate)
Selected Abstracts"Reverse degradomics", monitoring of proteolytic trimming by multi-CE and confocal detection of fluorescent substrates and reaction productsELECTROPHORESIS, Issue 13 2009Helene Piccard Abstract A platform for profiling of multiple proteolytic activities acting on one specific substrate, based on the use of a 96-channel capillary DNA sequencer with CE-LIF of labeled substrate peptides and reaction products is introduced. The approach consists of synthesis of a substrate peptide of interest, fluorescent labeling of the substrate, either aminoterminally by chemical coupling, or carboxyterminally by transglutaminase reaction, proteolysis by a biological mixture of proteases in the absence or presence of protease inhibitors, multi-channel analysis of substrate and reaction products, and data collection and processing. Intact substrate and reaction products, even when varying by only one amino acid, can be relatively semi-quantified in a high-throughput manner, yielding information on proteases acting in complex biological mixtures and without prepurification. Monitoring, classification and inhibition of multiple proteolytic activities are demonstrated on a model substrate, the aminoterminus of the mouse granulocyte chemotactic protein-2. In view of extensive processing of chemokines into various natural forms with different specific biological activities, and of the fragmentary knowledge of processing proteases, examples of processing by neutrophil degranulate, tumor cell culture fluids and plasma are provided. An example of selection and comparison of inhibitory mAbs illustrates that the platform is suitable for inhibitor screening. Whereas classical degradomics technologies analyze the substrate repertoire of one specific protease, here the complementary concept, namely the study of all proteases acting, in a biological context, on one specific substrate, is developed and tuned to identify key proteases and protease inhibitors for the processing of any biological substrate of interest. [source] Development of axonal pathways in the human fetal fronto-limbic brain: histochemical characterization and diffusion tensor imagingJOURNAL OF ANATOMY, Issue 4 2010Lana Vasung Abstract The development of cortical axonal pathways in the human brain begins during the transition between the embryonic and fetal period, happens in a series of sequential events, and leads to the establishment of major long trajectories by the neonatal period. We have correlated histochemical markers (acetylcholinesterase (AChE) histochemistry, antibody against synaptic protein SNAP-25 (SNAP-25-immunoreactivity) and neurofilament 200) with the diffusion tensor imaging (DTI) database in order to make a reconstruction of the origin, growth pattern and termination of the pathways in the period between 8 and 34 postconceptual weeks (PCW). Histological sections revealed that the initial outgrowth and formation of joined trajectories of subcortico-frontal pathways (external capsule, cerebral stalk,internal capsule) and limbic bundles (fornix, stria terminalis, amygdaloid radiation) occur by 10 PCW. As early as 11 PCW, major afferent fibers invade the corticostriatal junction. At 13,14 PCW, axonal pathways from the thalamus and basal forebrain approach the deep moiety of the cortical plate, causing the first lamination. The period between 15 and 18 PCW is dominated by elaboration of the periventricular crossroads, sagittal strata and spread of fibers in the subplate and marginal zone. Tracing of fibers in the subplate with DTI is unsuccessful due to the isotropy of this zone. Penetration of the cortical plate occurs after 24,26 PCW. In conclusion, frontal axonal pathways form the periventricular crossroads, sagittal strata and ,waiting' compartments during the path-finding and penetration of the cortical plate. Histochemistry is advantageous in the demonstration of a growth pattern, whereas DTI is unique for demonstrating axonal trajectories. The complexity of fibers is the biological substrate of selective vulnerability of the fetal white matter. [source] Colloidal soft matter as drug delivery systemJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 1 2009Giulia Bonacucina Abstract Growing interest is being dedicated to soft matter because of its potential in delivering any type of drugs. Since hydrophilic, lipophilic, small and big molecules can be loaded into these colloidal systems and administered through the parenteral or nonparenteral route, soft matter systems have been used to solve many biomedical and pharmaceutical problems. In fact, they make possible to overcome difficulties in the formulation and delivery of poorly water-soluble drug molecules, settle some stability issues typical of biological drug molecules, design parenteral sustained release forms and provide functionalized soft particles that are very effective in drug targeting. This review deals with the important role that colloids play in the drug delivery and targeting, with particular attention to the more currently used systems such as microemulsions, organogels, liposomes, micelles, and dendrimers. Though significant progress has been made in drug targeting, some challenges still remain. Further efforts will be required to better understand the characteristics of targets and to discover new ones. In-depth knowledge of the physico-chemical structure and properties of the systems used for targeting is fundamental for understanding the mechanism of interaction with the biological substrate and the consequent drug release. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:1,42, 2009 [source] Exceptionally preserved conulariids and an edrioasteroid from the Hunsrück Slate (Lower Devonian, SW Germany)PALAEONTOLOGY, Issue 2 2010HEYO VAN ITEN Abstract:, Nineteen partial specimens of Conularia sp., together with an articulated agelacrinitid edrioasteroid and several discinid brachiopods, occur in close association with a probable biological substrate on a small slab of silty Hunsrück Slate (Lower Devonian, Emsian) from Bundenbach, Germany. Most of the conulariids occur in V-like pairs or in a single cluster of 12 specimens arranged in a fan-like radial pattern. Together with the edrioasteroid and (possibly) brachiopods, the conulariids probably were attached to the substrate in life and then were buried and possibly killed by a single influx of silty mud. The apertural end of many of the conulariids is partially covered by inwardly folded short lappets, which may have closed in response to rapid (but gentle) burial. Rock matrix in the apertural region of the peridermal cavity of nearly all of the conulariids exhibits irregular, variably dense concentrations of pyrite. The concentrations occur almost exclusively within the conulariids, where they probably formed as a result of the decay of retracted conulariid soft parts. Although the concentrations lack clearly defined anatomical features that can be unambiguously homologized with particular anatomical structures of any extant taxon, their form and distribution within the conulariids are consistent with the hypothesis that conulariids were polypoid scyphozoans. [source] Adsorption of 6-mercaptopurine and 6-mercaptopurine-ribosideon silver colloid: A pH-dependent surface-enhanced Raman spectroscopy and density functional theory study.BIOPOLYMERS, Issue 6 2005Abstract Surface-enhanced Raman spectroscopy (SERS) has been applied to characterize the interaction of 6-mercaptopurine-ribose (6MPR), an active drug used in chemotherapy of acute lymphoblastic leukemia, with a model biological substrate at therapeutic concentrations and as function of the pH value. Therefore, a detailed vibrational analysis of crystalline and solvated (6MPR) based on Density Functional Theory (DFT) calculations of the thion and thiol tautomers has been performed. 6MPR adopts the thion tautomeric form in the polycrystalline state. The SERS spectra of 6MPR and 6-mercaptopurine (6MP) recorded on silver colloid provided evidence that the ribose derivative shows different adsorption behavior compared with the free base. Under acidic conditions, the adsorption of 6MPR on the metal surface via the N7 and possibly S atoms was proposed to have a perpendicular orientation, while 6MP is probably adsorbed through the N9 and N3 atoms. Under basic conditions both molecules are adsorbed through the N1 and possibly S atoms, but 6MP has a more tilted orientation on the silver colloidal surface while 6MPR adopts a perpendicular orientation. The reorientation of the 6MPR molecule on the surface starts at pH 8 while in the case of 6MP the reorientation starts around pH 6. Under basic conditions, the presence of the anionic molecular species for both molecules is suggested. The deprotonation of 6MP is completed at pH 8 while the deprotonation of the riboside is finished at pH 10. For low drug concentrations under neutral conditions and for pH values 8 and 9, 6MPR interacts with the substrate through both N7 and N1 atoms, possibly forming two differently adsorbed species, while for 6MP only one species adsorbed via N1 was evidenced. © 2005 Wiley Periodicals, Inc. Biopolymers 78: 298,310, 2005 This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source] Age effects on the regulation of adult hippocampal neurogenesis by physical activity and environmental enrichment in the APP23 mouse model of Alzheimer diseaseHIPPOCAMPUS, Issue 10 2009Sebastian Mirochnic Abstract An active lifestyle is to some degree protective against Alzheimer's disease (AD), but the biological basis for this benefit is still far from clear. We hypothesize that physical and cognitive activity increase a reserve for plasticity by increasing adult neurogenesis in the hippocampal dentate gyrus (DG). We thus assessed how age affects the response to activity in the murine APP23 model of AD compared with wild type (WT) controls and studied the effects of physical exercise (RUN) and environmental enrichment (ENR) in comparison with standard housing (CTR) at two different ages (6 months and 18 months) and in both genotypes. At 18 months, both activity paradigms reduced the hippocampal human A,1-42/A,1-40 ratio when compared with CTR, despite a stable plaque load in the hippocampus. At this age, both RUN and ENR increased the number of newborn granule cells in the DG of APP23 mice when compared with CTR, whereas the levels of regulation were equivalent to those in WT mice under the same housing conditions. At 6 months, however, neurogenesis in ENR but not RUN mice responded like the WT. Quantifying the number of cells at the doublecortin-positive stage in relation to the number of cells on postmitotic stages we found that ENR overproportionally increased the number of the DCX-positive "late" progenitor cells, indicative of an increased potential to recruit even more new neurons. In summary, the biological substrates for activity-dependent regulation of adult hippocampal neurogenesis were preserved in the APP23 mice. We thus propose that in this model, ENR even more than RUN might contribute to a "neurogenic reserve" despite a stable plaque load and that age affects the outcome of an interaction based on "activity." © 2009 Wiley-Liss, Inc. [source] Computational studies of electron-transfer processes in old yellow enzymeINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 6 2001Ginger M. Chateauneuf Abstract Old Yellow Enzyme (OYE) is a flavoenzyme that was first isolated from brewer's bottom yeast. Homologues have been identified in other strains of yeast, bacteria, and plants. In plants, the OYE homologue functions enzymatically in the synthesis of plant hormones, but the biological function of OYE in yeast is still unknown. Flavin mononucleotide (FMN) is the cofactor that is noncovalently bound in the enzyme. OYE binds several phenolic ligands that serve as models for reactive biological substrates. These complexes have broad long-wavelength absorption bands, which have been ascribed to charge-transfer interactions, with the phenolate anion acting as the electron donor and the FMN as the acceptor [Abramovitz, A. S.; Massey, V. J Bio Chem 1976, 251, 5327,5336]. The computational characterization of these electronic transitions in the active site will help in understanding the biological processes in the enzyme. It was found that at several levels of computational methods, and through computationally mutating relevant amino acids, a charge-transfer process is occurring. This result agrees with previous experimental work and is consistent with all ultraviolet,visible spectrophotometric data. The preliminary results for the computational studies of these electron-transfer processes will be presented. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001 [source] Cytosolic NADP phosphatases I and II from Arthrobacter sp. strain KM: Implication in regulation of NAD+/NADP+ balanceJOURNAL OF BASIC MICROBIOLOGY, Issue 3 2004Shigeyuki Kawai NADP phosphatase (NADPase) is an enzyme that converts NADP+ into NAD+ through dephosphorylation of NADP+, and is considered to be one of the possible candidates for regulation of the NAD+/NADP+ balance in vivo. In order to obtain an intrinsic NADPase, the NADP+ -degrading activity in a membrane-free cell extract of a Gram-positive bacterium, Arthrobacter sp. strain KM, was first assessed and demonstrated to be mainly achieved through the NADPase reaction, indicating NADPase is essential for degradation of NADP+ and therefore for regulation of the NAD+/NADP+ balance in cytosol. Then, the isolation of cytosolic NADPase was attempted using NADP+ as a substrate. Two NADPase isozymes, designated as NADPases I and II, were purified from the cell extract of the bacterium, and were indicated to be the sole cytosolic NADPases regulating the balance of NAD+/NADP+. NADPases I and II are homodimers of 32 and 30 kDa subunits, respectively, and most active at pH 7,8. The N-terminal amino acid sequences of the two enzymes are similar to each other. Among the biological substrates tested, both enzymes showed the highest activity toward NADP+ and NADPH. AMP, ADP, and pyridoxal 5,-phosphate were also dephosphorylated, but to lower extents. Comparison of the features of NADPases I and II with those of other acid phosphatases possessing NADPase activity suggested that NADPases I and II are novel enzymes participating in regulation of the NAD+/NADP+ balance in the cytosol. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Decision-Making Biases, Antisocial Personality, and Early-Onset AlcoholismALCOHOLISM, Issue 7 2000Carlos A. Mazas Background: Disinhibited, antisocial traits increase the risk for early-onset alcoholism. Research also suggests that decision biases which favor immediate large rewards regardless of long-term consequences may be important mechanisms associated with the biological substrates of antisocial traits. This study tested the hypothesis that early-onset alcoholism with antisocial personality (ASP) would be associated with favoring immediate larger rewards despite their being associated with long-term losses. Methods: Twenty-seven early-onset alcoholics with and without a diagnosis of ASP, eight subjects with ASP but no alcohol dependence, and 32 controls were tested on a task that manipulated the magnitude of immediate rewards and the magnitude of long-term punishments. The sample was recruited from the community via advertisements. Results: Compared with subjects without ASP, subjects with ASP favored larger immediate rewards despite long-term losses regardless of alcohol dependence; however, they learned to shift their decisions in a more advantageous direction over time. A disadvantageous decision bias also was associated with drinking greater quantities of alcohol and having a lower IQ. Conclusions: This study suggests that ASP in a young adult noninstitutionalized sample was associated with a pattern of disadvantageous decision making similar to that observed in patients with antisocial behavioral characteristics associated with lesions in the ventromedial frontal cortex. The data also suggest that this pattern of disadvantageous decision making is associated with consuming larger quantities of alcohol but not consuming alcohol more frequently. [source] The relationship between the electrospray ionization behaviour and biological activity of some phosphino Cu(I) complexesRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 11 2010Francesco Tisato Electrospray ionization mass spectrometry was usefully employed for the characterization of three phosphino copper(I) complexes of medicinal interest. This technique revealed that the original [CuL4]+ pro-drugs (L,=,hydrophilic tertiary phosphine) underwent dissociation with production of coordinative unsaturated [CuL3]+ and [CuL2]+ species, which represented key intermediates for the activation of potential biological properties. The more favoured was the displacement of the ligands from the [CuL4]+ parent complex, the more favoured was in turn the possibility for the metal ion to directly interact with biological substrates, including pharmacological targets related to cancer proliferation. An inverse correlation between the stability and the cytotoxic activity of the three copper(I) complexes investigated has been clearly established. Copyright © 2010 John Wiley & Sons, Ltd. [source] The temperament of pre-term, low birth weight infants and its potential biological substratesRESEARCH IN NURSING & HEALTH, Issue 6 2004Sandra J. Weiss Abstract Temperament profiles of pre-term, low birth weight (LBW) infants were assessed at 6 months of age using standardized norms from the Revised Infant Temperament Questionnaire (RITQ). The contributions of perinatal risk, ethnicity, and gender to various temperament dimensions were examined. The sample included 152 infants with a mean birth weight of 1687 g and a mean gestational age of 31 weeks. Eighty percent of the infants were classified as having temperaments that were difficult to manage. Irregularity of the infants' biorhythms, slowness in their ability to adapt to changes, and distractibility were the most problematic. Birth weight, gestational age, and gender were not associated with temperament. Perinatal morbidity was related to the temperament dimension of infant persistence, with implications for the infant's attention span and task performance. Euro American infants were rated as more persistent and less intense in emotional expression than were infants of other ethnic groups. Results suggest the need for a more direct assessment of the effects of neurobiological processes on development of temperament phenotypes and for measurement of temperament that is socioculturally appropriate. © 2004 Wiley Periodicals, Inc. Res Nurs Health 27:392,402, 2004 [source] | ||||||||||||||||