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Strong Reduction (strong + reduction)
Selected AbstractsSoils of a Mediterranean hot spot of biodiversity and endemism (Sardinia, Tyrrhenian Islands) are inhabited by pan-European, invasive species of Hypocrea/TrichodermaENVIRONMENTAL MICROBIOLOGY, Issue 1 2009Quirico Migheli Summary We have used a Mediterranean hot spot of biodiversity (the Island of Sardinia) to investigate the impact of abiotic factors on the distribution of species of the common soil fungus Trichoderma. To this end, we isolated 482 strains of Hypocrea/Trichoderma from 15 soils comprising undisturbed and disturbed environments (forest, shrub lands and undisturbed or extensively grazed grass steppes respectively). Isolates were identified at the species level by the oligonucleotide BarCode for Hypocrea/Trichoderma (TrichOKEY), sequence similarity analysis (Trichoblast) and phylogenetic inferences. The majority of the isolates were positively identified as pan-European and/or pan-global Hypocrea/Trichoderma species from sections Trichoderma and Pachybasium, comprising H. lixii/T. harzianum, T. gamsii, T. spirale, T. velutinum, T. hamatum, H. koningii/T. koningii, H. virens/T. virens, T. tomentosum, H. semiorbis, H. viridescens/T. viridescens, H. atroviridis/T. atroviride, T. asperellum, H. koningiopsis/T. koningiopsis and Trichoderma sp. Vd2. Only one isolate represented a new, undescribed species belonging to the Harzianum,Catoptron Clade. Internal transcribed spacer sequence analysis revealed only one potentially endemic internal transcribed spacer 1 allele of T. hamatum. All other species exhibited genotypes that were already found in Eurasia or in other continents. Only few cases of correlation of species occurrence with abiotic factors were recorded. The data suggest a strong reduction of native Hypocrea/Trichoderma diversity, which was replaced by extensive invasion of species from Eurasia, Africa and the Pacific Basin. [source] Physiological responses of Matricaria chamomilla to cadmium and copper excessENVIRONMENTAL TOXICOLOGY, Issue 1 2008Jozef Kovį Abstract Physiological responses of Matricaria chamomilla plants exposed to cadmium (Cd) and copper (Cu) excess (3, 60, and 120 ,M for 7 days) with special emphasis on phenolic metabolism were studied. Cu at 120 ,M reduced chamomile growth, especially in the roots where it was more abundant than Cd. Notwithstanding the low leaf Cu amount (37.5 ,g g,1 DW) in comparison with Cd (237.8 ,g g,1 DW) at 120 ,M, it caused reduction of biomass accumulation, Fv/Fm ratio and soluble proteins. In combination with high accumulation of phenolics, strong reduction of proteins and high GPX activity in the roots, this supports severe redox Cu properties. In terms of leaf phenylalanine ammonia-lyase (PAL) activity, it seems that Cd had a stimulatory effect during the course of the experiment, whereas Cu was found to stimulate it after 7-day exposure. The opposite trend was visible in the roots, where Cd had a stimulatory effect at high doses but Cu mainly at the highest dose. This supports the assumption of different PAL time dynamics under Cd and Cu excess. A dose of 60 and 120 ,M Cu led to 2- and 3-times higher root lignin accumulation while the same Cd doses increased it by 33 and 68%, respectively. A Cu dose of 120 ,M can be considered as limiting for chamomile growth under conditions of present research, while resistance to high Cd doses was confirmed. However, PAL and phenolics seemed to play an important role in detoxification of Cd- and Cu-induced oxidative stress. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2008. [source] PRECLINICAL STUDY: FULL ARTICLE: Altered architecture and functional consequences of the mesolimbic dopamine system in cannabis dependenceADDICTION BIOLOGY, Issue 3 2010Saturnino Spiga ABSTRACT Cannabinoid withdrawal produces a hypofunction of mesencephalic dopamine neurons that impinge upon medium spiny neurons (MSN) of the forebrain. After chronic treatment with two structurally different cannabinoid agonists, ,9 -tetrahydrocannabinol and CP55 940 (CP) rats were withdrawn spontaneously and pharmacologically with the CB1 antagonist SR141716A (SR). In these two conditions, evaluation of tyrosine hydroxylase (TH)-positive neurons revealed significant morphometrical reductions in the ventrotegmental area but not substantia nigra pars compacta of withdrawn rats. Similarly, confocal analysis of Golgi,Cox-stained sections of the nucleus accumbens revealed a decrease in the shell, but not the core, of the spines' density of withdrawn rats. Administration of the CB1 antagonist SR to control rats, provoked structural abnormalities reminiscent of those observed in withdrawal conditions and support the regulatory role of cannabinoids in neurogenesis, axonal growth and synaptogenesis by acting as eu-proliferative signals through the CB1 receptors. Further, these measures were incorporated into a realistic computational model that predicts a strong reduction in the excitability of morphologically altered MSN, yielding a significant reduction in action potential output. These pieces of evidence support the tenet that withdrawal from addictive compounds alters functioning of the mesolimbic system and provide direct morphological evidence for functional abnormalities associated with cannabinoid dependence at the level of dopaminergic neurons and their postsynaptic counterpart and are coherent with recent hypothesis underscoring a hypodopaminergic state as a distinctive feature of the ,addicted brain'. [source] In vivo blockade of neural activity alters dendritic development of neonatal CA1 pyramidal cellsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 10 2002Laurent Groc Abstract During development, neural activity has been proposed to promote neuronal growth. During the first postnatal week, the hippocampus is characterized by an oscillating neural network activity and a rapid neuronal growth. In the present study we tested in vivo, by injecting tetanus toxin into the hippocampus of P1 rats, whether this neural activity indeed promotes growth of pyramidal cells. We have previously shown that tetanus toxin injection leads to a strong reduction in the frequency of spontaneous GABA and glutamatergic synaptic currents, and to a complete blockade of the early neural network activity during the first postnatal week. Morphology of neurobiotin-filled CA1 pyramidal cells was analyzed at the end of the first postnatal week (P6,10). In activity-reduced neurons, the total length of basal dendritic tree was three times less than control. The number, but not the length, of basal dendritic branches was affected. The growth impairment was restricted to the basal dendrites. The apical dendrite, the axons, or the soma grew normally during activity deprivation. Thus, the in vivo neural activity in the neonate hippocampus seems to promote neuronal growth by initiating novel branches. [source] Assignment of the [4Fe-4S] clusters of Ech hydrogenase from Methanosarcina barkeri to individual subunits via the characterization of site-directed mutantsFEBS JOURNAL, Issue 18 2005Lucia Forzi Ech hydrogenase from Methanosarcina barkeri is a member of a distinct group of membrane-bound [NiFe] hydrogenases with sequence similarity to energy-conserving NADH:quinone oxidoreductase (complex I). The sequence of the enzyme predicts the binding of three [4Fe-4S] clusters, one by subunit EchC and two by subunit EchF. Previous studies had shown that two of these clusters could be fully reduced under 105 Pa of H2 at pH 7 giving rise to two distinct S½ electron paramagnetic resonance (EPR) signals, designated as the g = 1.89 and the g = 1.92 signal. Redox titrations at different pH values demonstrated that these two clusters had a pH-dependent midpoint potential indicating a function in ion pumping. To assign these signals to the subunits of the enzyme a set of M. barkeri mutants was generated in which seven of eight conserved cysteine residues in EchF were individually replaced by serine. EPR spectra recorded from the isolated mutant enzymes revealed a strong reduction or complete loss of the g = 1.92 signal whereas the g = 1.89 signal was still detectable as the major EPR signal in five mutant enzymes. It is concluded that the cluster giving rise to the g = 1.89 signal is the proximal cluster located in EchC and that the g = 1.92 signal results from one of the clusters of subunit EchF. The pH-dependence of these two [4Fe-4S] clusters suggests that they simultaneously mediate electron and proton transfer and thus could be an essential part of the proton-translocating machinery. [source] Biophysical characterization of the interaction of Limulus polyphemus endotoxin neutralizing protein with lipopolysaccharideFEBS JOURNAL, Issue 10 2004Jörg Andrä Endotoxin-neutralizing protein (ENP) of the horseshoe crab is one of the most potent neutralizers of endotoxins [bacterial lipopolysaccharide (LPS)]. Here, we report on the interaction of LPS with recombinant ENP using a variety of physical and biological techniques. In biological assays (Limulus amebocyte lysate and tumour necrosis factor-, induction in human mononuclear cells), ENP causes a strong reduction of the immunostimulatory ability of LPS in a dose-dependent manner. Concomitantly, the accessible negative surface charges of LPS and lipid A (zeta potential) are neutralized and even converted into positive values. The gel to liquid crystalline phase transitions of LPS and lipid A shift to higher temperatures indicative of a rigidification of the acyl chains, however, the only slight enhancement of the transition enthalpy indicates that the hydrophobic moiety is not strongly disturbed. The aggregate structure of lipid A is converted from a cubic into a multilamellar phase upon ENP binding, whereas the secondary structure of ENP does not change due to the interaction with LPS. ENP contains a hydrophobic binding site to which the dye 1-anilino-8-sulfonic acid binds at a Kd of 19 µm, which is displaced by LPS. Because lipopolysaccharide-binding protein (LBP) is not able to bind to LPS when ENP and LPS are preincubated, tight binding of ENP to LPS can be deduced with a Kd in the low nonomolar range. Importantly, ENP is able to incorporate by itself into target phospholipid liposomes, and is also able to mediate the intercalation of LPS into the liposomes thus acting as a transport protein in a manner similar to LBP. Thus, LPS,ENP complexes might enter target membranes of immunocompetent cells, but are not able to activate due to the ability of ENP to change LPS aggregates from an active into an inactive form. [source] Biogeochemical changes induced in uranium mining waste pile samples by uranyl nitrate treatments under anaerobic conditionsGEOBIOLOGY, Issue 3 2009A. GEISSLER Response of the subsurface soil bacterial community of a uranium mining waste pile to treatments with uranyl nitrate over different periods of time was studied under anaerobic conditions. The fate of the added U(VI) without supplementation with electron donors was investigated as well. By using 16S rRNA gene retrieval, we demonstrated that incubation with uranyl nitrate for 4 weeks resulted in a strong reduction in and even disappearance of some of the most predominant bacterial groups of the original sample. Instead, a strong proliferation of denitrifying and uranium-resistant populations of Rahnella spp. from Gammaproteobacteria and of Firmicutes occurred. After longer incubations for 14 weeks with uranyl nitrate, bacterial diversity increased and populations intrinsic to the untreated samples such as Bacteroidetes and Deltaproteobacteria propagated and replaced the above-mentioned uranium-resistant groups. This indicated that U(VI) was immobilized. Mössbauer spectroscopic analysis revealed an increased Fe(III) reduction by increasing the incubation time from four to 14 weeks. This result signified that Fe(III) was used as an electron acceptor by the bacterial community established at the later stages of the treatment. X-ray absorption spectroscopic analysis demonstrated that no detectable amounts of U(VI) were reduced to U(IV) in the time frames of the performed experiments. The reason for this observation is possibly due to the low level of electron donors in the studied oligotrophic environment. Time-resolved laser-induced fluorescence spectroscopic analysis demonstrated that most of the added U(VI) was bound by organic or inorganic phosphate phases both of biotic origin. [source] Climate change hastens the turnover of stream fish assemblagesGLOBAL CHANGE BIOLOGY, Issue 10 2008LAĖTITIA BUISSON Abstract Stream fish are expected to be significantly influenced by climate change, as they are ectothermic animals whose dispersal is limited within hydrographic networks. Nonetheless, they are also controlled by other physical factors that may prevent them moving to new thermally suitable sites. Using presence,absence records in 655 sites widespread throughout nine French river units, we predicted the potential future distribution of 30 common stream fish species facing temperature warming and change in precipitation regime. We also assessed the potential impacts on fish assemblages' structure and diversity. Only cold-water species, whose diversity is very low in French streams, were predicted to experience a strong reduction in the number of suitable sites. In contrast, most cool-water and warm-water fish species were projected to colonize many newly suitable sites. Considering that cold headwater streams are the most numerous on the Earth's surface, our results suggested that headwater species would undergo a deleterious effect of climate change, whereas downstream species would expand their range by migrating to sites located in intermediate streams or upstream. As a result, local species richness was forecasted to increase greatly and high turnover rates indicated future fundamental changes in assemblages' structure. Changes in assemblage composition were also positively related to the intensity of warming. Overall, these results (1) stressed the importance of accounting for both climatic and topographic factors when assessing the future distribution of riverine fish species and (2) may be viewed as a first estimation of climate change impacts on European freshwater fish assemblages. [source] Cholinergic suppression of excitatory synaptic responses in layer II of the medial entorhinal cortexHIPPOCAMPUS, Issue 2 2007Bassam N. Hamam Abstract Theta-frequency (4,12 Hz) electroencephalographic activity is thought to play a role in mechanisms mediating sensory and mnemonic processing in the entorhinal cortex and hippocampus, but the effects of acetylcholine on excitatory synaptic inputs to the entorhinal cortex are not well understood. Field excitatory postsynaptic potentials (fEPSPs) evoked by stimulation of the piriform (olfactory) cortex were recorded in the medial entorhinal cortex during behaviors associated with theta activity (active mobility) and were compared with those recorded during nontheta behaviors (awake immobility and slow wave sleep). Synaptic responses were smaller during behavioral activity than during awake immobility and sleep, and responses recorded during movement were largest during the negative phase of the theta rhythm. Systemic administration of cholinergic agonists reduced the amplitude of fEPSPs, and the muscarinic receptor blocker scopolamine strongly enhanced fEPSPs, suggesting that the theta-related suppression of fEPSPs is mediated in part by cholinergic inputs. The reduction in fEPSPs was investigated using in vitro intracellular recordings of EPSPs in Layer II neurons evoked by stimulation of Layer I afferents. Constant bath application of the muscarinic agonist carbachol depolarized membrane potential and suppressed EPSP amplitude in Layer II neurons. The suppression of EPSPs was not associated with a substantial change in input resistance, and could not be accounted for by a depolarization-induced reduction in driving force on the EPSP. The GABAA receptor-blocker bicuculline (50 ,M) did not prevent the cholinergic suppression of EPSPs, suggesting that the suppression is not dependent on inhibitory mechanisms. Paired-pulse facilitation of field and intracellular EPSPs were enhanced by carbachol, indicating that the suppression is likely due to inhibition of presynaptic glutamate release. These results indicate that, in addition to well known effects on postsynaptic conductances that increase cellular excitability, cholinergic activation in the entorhinal cortex results in a strong reduction in strength of excitatory synaptic inputs from the piriform cortex. © 2006 Wiley-Liss, Inc. [source] On being the right size: food-limited feedback on optimal body sizeJOURNAL OF ANIMAL ECOLOGY, Issue 4 2008Sinclair Anthony R.E An insular population of white-tailed deer Odocoileus virginianus introduced in 1896 to predator-free Anticosti Island, Quebec, has caused long-term changes in the plant community. Food quality declined as did body weight. Although different parameters of reproduction changed, overall reproductive rates remained similar, thus maintaining deer density and promoting further change in habitat. These results show (i) long-term feedbacks on carrying capacity, (ii) the mechanism for reduction of body mass, and (iii) the lack of strong reduction in reproductive rates to regulate the population at high density, a feature of Eutherians. They are relevant to mechanisms determining the evolution of vertebrate body sizes. [source] Fractionation of Electrograms and Linking of Activation During Pharmacologic Cardioversion of Persistent Atrial Fibrillation in the GoatJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 5 2004ZHAOLIANG SHAN M.D. Introduction: During atrial fibrillation (AF), there is fractionation of extracellular potentials due to head-to-tail interaction and slow conduction of fibrillation waves. We hypothesized that slowing of the rate of AF by infusion of a Class I drug would increase the degree of organization of AF. Methods and Results: Seven goats were instrumented with 83 epicardial electrodes on the left atrium, left atrial appendage, Bachmann's bundle, right atrium, and right atrial appendage. AF was induced and maintained by an automatic atrial fibrillator. After AF had persisted for 4 weeks, the Class IC drug cibenzoline was infused at a rate of 0.1 mg/kg/min. AF cycle length (AFCL), the percentage of fractionated potentials, conduction velocity (CV), and direction of propagation of the fibrillation waves were measured during baseline, after AFCL was increased by 20, 40, 60, and 80 ms, and shortly before cardioversion. Infusion of cibenzoline increased the mean of the median AFCLs from 96 ± 6 ms to 207 ± 43 ms (P < 0.0001). The temporal variation in AFCL in different parts of the atria was 8% to 20% during control and, with the exception of Bachmann's bundle, was not significantly reduced during cibenzoline infusion. CV decreased from 76 ± 14 ms to 52 ± 9 cm/s (P < 0.01). Cibenzoline increased the percentage of single potentials from 81%± 4% to 91%± 4% (P < 0.01) and decreased the incidence of double potentials from 14%± 4% to 7 ± 5% (P < 0.01) and multiple potentials from 5%±% to 1%± 2% (P < 0.001). Whereas during control, linking (consecutive waves propagating in the same direction) during seven or more beats occurred in 9%± 15% of the cycles, after cibenzoline the degree of linking had increased to 40%± 33% (P < 0.05). During the last two beats before cardioversion, there was a sudden prolongation in AFCL from 209 ± 37 ms to 284 ± 92 ms (P < 0.01) and a strong reduction in fractionated potentials (from 22%± 12% to 6%± 5%, P < 0.05). Conclusion: The Class IC drug cibenzoline causes a decrease in fractionation of fibrillation electrograms and an increase in the degree of linking during AF. This supports the observation that Class I drugs widen the excitable gap during AF. (J Cardiovasc Electrophysiol, Vol. 15, pp. 572-580, May 2004) [source] Haemopexin affects iron distribution and ferritin expression in mouse brainJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 10 2009Noemi Morello Abstract Haemopexin (Hx) is an acute phase plasma glycoprotein, mainly produced by the liver and released into plasma where it binds heme with high affinity and delivers it to the liver. This system provides protection against free heme-mediated oxidative stress, limits access by pathogens to heme and contributes to iron homeostasis by recycling heme iron. Hx protein has been found in the sciatic nerve, skeletal muscle, retina, brain and cerebrospinal fluid (CSF). Recently, a comparative proteomic analysis has shown an increase of Hx in CSF from patients with Alzheimer's disease, thus suggesting its involvement in heme detoxification in brain. Here, we report that Hx is synthesised in brain by the ventricular ependymal cells. To verify whether Hx is involved in heme scavenging in brain, and consequently, in the control of iron level, iron deposits and ferritin expression were analysed in cerebral regions known for iron accumulation. We show a twofold increase in the number of iron-loaded oligodendrocytes in the basal ganglia and thalamus of Hx-null mice compared to wild-type controls. Interestingly, there was no increase in H- and L-ferritin expression in these regions. This condition is common to several human neurological disorders such as Alzheimer's disease and Parkinson's disease in which iron loading is not associated with an adequate increase in ferritin expression. However, a strong reduction in the number of ferritin-positive cells was observed in the cerebral cortex of Hx-null animals. Consistent with increased iron deposits and inadequate ferritin expression, malondialdehyde level and Cu,Zn superoxide dismutase-1 expression were higher in the brain of Hx-null mice than in that of wild-type controls. These data demonstrate that Hx plays an important role in controlling iron distribution within brain, thus suggesting its involvement in iron-related neurodegenerative diseases. [source] Ethanol inhibits cold-menthol receptor TRPM8 by modulating its interaction with membrane phosphatidylinositol 4,5-bisphosphateJOURNAL OF NEUROCHEMISTRY, Issue 1 2007Jan Benedikt Abstract Ethanol has opposite effects on two members of the transient receptor potential (TRP) family of ion channels: it inhibits the cold-menthol receptor TRPM8, whereas it potentiates the activity of the heat- and capsaicin-gated vanilloid receptor TRPV1. Both thermosensitive cation channels are critically regulated by the membrane lipid, phosphatidylinositol 4,5-bisphosphate (PIP2). The effects of this phospholipid on TRPM8 and TRPV1 are also functionally opposite: PIP2 is necessary for the activation of TRPM8 but it constitutively inhibits TRPV1. This parallel led us to investigate the possible role of PIP2 in the ethanol-induced modulation of rat TRPM8, heterologously expressed in HEK293T cells. In this study, we characterize the effects of ethanol (0.1,10%) on whole-cell currents produced by menthol and by low temperature (< 17°C). We show that the inclusion of PIP2 in the intracellular solution results in a strong reduction in the ethanol-induced inhibition of menthol-evoked responses. Conversely, intracellular dialysis with anti-PIP2 antibody or with the PIP2 scavenger, poly l -lysine, enhanced the ethanol-induced inhibition of TRPM8. A 20 min pre-incubation with wortmannin caused a modest decrease in inhibition produced by 1% ethanol, indicating that the ethanol-induced inhibition is not mediated by lipid kinases. These findings suggest that ethanol inhibits TRPM8 by weakening the PIP2,TRPM8 channel interaction; a similar mechanism may contribute to the ethanol-mediated modulation of some other PIP2 -sensitive TRP channels. [source] L -NAME reverses quinolinic acid-induced toxicity in rat corticostriatal slices: Involvement of src family kinasesJOURNAL OF NEUROSCIENCE RESEARCH, Issue 12 2007Cinzia Mallozzi Abstract Quinolinic acid (QA) is an endogenous excitotoxin acting on N -methyl- d -aspartate receptors (NMDARs) that leads to the pathologic and neurochemical features similar to those observed in Huntington's disease (HD). The mechanism of QA toxicity also involves free radicals formation and oxidative stress. NMDARs are particularly vulnerable to the action of reactive oxygen species (ROS) and reactive nitrogen species (RNS) that can act as modulators of the activity of protein tyrosine kinases (PTKs) and phosphotyrosine phosphatases (PTPs). Because QA is able to activate neuronal nitric oxide synthase (nNOS) as well as to stimulate the NMDARs, we evaluated the effect of N,-Nitro- l -arginine-methyl ester (l -NAME), a selective nNOS inhibitor, on QA-induced neurotoxicity in rat corticostriatal slices. In electrophysiologic experiments we observed that slice perfusion with QA induced a strong reduction of field potential (FP) amplitude, followed by a partial recovery at the end of the QA washout. In the presence of l -NAME the recovery of FP amplitude was significantly increased with respect to QA alone. In synaptosomes, prepared from corticostriatal slices after the electrophysiologic recordings, we observed that l -NAME pre-incubation reversed the QA-mediated inhibitory effects on protein tyrosine phosphorylation pattern, c-src, lyn, and fyn kinase activities and tyrosine phosphorylation of NMDAR subunit NR2B, whereas the PTP activity was not recovered in the presence of l -NAME. These findings suggest that NO plays a key role in the molecular mechanisms of QA-mediated excitotoxicity in experimental model of HD. © 2007 Wiley-Liss, Inc. [source] Thermodynamic origin of the chiral recognition of tryptophan on teicoplanin and teicoplanin aglycone stationary phasesJOURNAL OF SEPARATION SCIENCE, JSS, Issue 5 2005Mohamed Haroun Abstract The D-, L-tryptophan binding and the chiral recognition properties of the teicoplanin and teicoplanin aglycone (TAG) chiral stationary phase (CSPs) were compared at various column temperatures. The solute adsorption isotherms (bi-Langmuir model) were determined for both the two CSPs using the perturbation method. It was demonstrated that the sugar units were involved in the reduction of the apparent enantioselectivity through two phenomena: (i) the inhibition of some enantioselective contacts with low-affinity binding regions of the aglycone and (ii) a decrease in the stereoselective properties of the aglycone high-affinity binding pocket. The phenomenon (ii) was governed by both a decrease in the ratio of the enantiomer adsorption constant and a strong reduction of the site accessibility for D- and L-tryptophan. In addition, a temperature effect study was performed to investigate the chiral recognition mechanism at the aglycone high-affinity pocket. An enthalpy-entropy compensation analysis derived from the Grunwald model as well as the comparison with the literature data demonstrated that the enantioselective binding mode was dependent on an interface dehydration process. The change in the enantioselective process observed between the TAG and teicoplanin CSP was characterized by a difference of ca. 2,3 ordered water molecules released from the species interface. [source] Homozygous Defects In Lmna, Encoding Lamin A/C Nuclear-Envelope Proteins, Cause Autosomal Recessive Axonal Neuropathy In Human (Charcot-Marie-Tooth Disorder Type 2) And MouseJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 3 2002A De Sandre-Giovannoli The Charcot-Marie-Tooth (CMT) disorders comprise a group of clinically and genetically heterogeneous hereditary motor and sensory neuropathies, which are mainly characterized by muscle weakness and wasting, foot deformities, and electrophysiological, as well as histological, changes. A subtype, CMT2, is defined by a slight or absent reduction of nerve-conduction velocities together with the loss of large myelinated fibers and axonal degeneration. CMT2 phenotypes are also characterized by a large genetic heterogeneity, although only two genes-NF-L and KIF1Bbeta-have been identified to date. Homozygosity mapping in inbred Algerian families with autosomal recessive CMT2 (AR-CMT2) provided evidence of linkage to chromosome 1q21.2-q21.3 in two families (Z(max) = 4.14). All patients shared a common homozygous ancestral haplotype that was suggestive of a founder mutation as the cause of the phenotype. A unique homozygous mutation in LMNA (which encodes lamin A/C, a component of the nuclear envelope) was identified in all affected members and in additional patients with CMT2 from a third, unrelated family. Ultrastructural explor- ation of sciatic nerves of LMNA null (i.e., ,/,) mice was performed and revealed a strong reduction of axon density, axonal enlargement, and the presence of nonmyelinated axons, all of which were highly similar to the phenotypes of human peripheral axonopathies. The finding of site-specific amino acid substitutions in limb-girdle muscular dystrophy type 1B, autosomal dominant Emery-Dreifuss muscular dystrophy, dilated cardiomyopathy type 1A, autosomal dominant partial lipodystrophy, and, now, AR-CMT2 suggests the existence of distinct functional domains in lamin A/C that are essential for the maintenance and integrity of different cell lineages. To our knowledge, this report constitutes the first evidence of the recessive inheritance of a mutation that causes CMT2; additionally, we suggest that mutations in LMNA may also be the cause of the genetically overlapping disorder CMT2B1. [source] Nutrient requirements of ephemeral plant species from wet, mesotrophic soilsJOURNAL OF VEGETATION SCIENCE, Issue 3 2001Emiel; Brouwer van der Meijden (1996) Abstract. Nanocyperion plant communities occur on wet, more or less nutrient-poor and sparsely vegetated soils in temperate climates and are characterized by tiny, very shortlived plant species. Most of these have become locally extinct. It is generally assumed that drainage and eutrophication were the most important reasons for this decrease. However, chemical analysis of soil pore water from plots on growth sites of these ephemerals showed that phosphorus availability was relatively high. In a greenhouse experiment, the growth of ephemeral species was strongly limited by the amount of available phosphorus, whereas there was little or no limitation to the growth of other plant species from this habitat. At low phosphorus concentrations, the ephemeral species reached their reproductive phase within the same period, but showed a strong reduction in the amount of flowers that were produced. We concluded that ephemeral species in particular require a minimum amount of phosphorus for reproduction. Other species on nutrient-poor, wet soils have a longer life span and can postpone flowering in nutrient-poor soils. In contrast to other short-lived plant species from the same habitat, the growth of ephemeral species was barely stimulated by enhanced nitrogen availability. Apparently, the ephemerals are adapted to low nitrogen concentrations. The occurrence on nitrogen-poor and relatively phosphorus-rich soils suggests that this community may be very sensitive to nitrogen deposition. Reduced phosphorus availability below the minimum requirements of ephemerals, for example after acidification or the exclusion of human activities, has possibly contributed to the decrease of ephemeral plant species. [source] Immiscible Poly(L -lactide)/Poly(, -caprolactone) Blends: Influence of the Addition of a Poly(L -lactide)-Poly(oxyethylene) Block Copolymer on Thermal Behavior and MorphologyMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 7 2004Giovanni Maglio Abstract Summary: A binary blend of poly (L -lactide) (PLLA) and poly(, -caprolactone) (PCL) of composition 70:30 by weight was prepared using a twin screw miniextruder and investigated by differential scanning calorimetry (DSC), optical microscopy and scanning electron microscopy (SEM). Ternary 70:30:2 blends were also obtained by adding either a diblock copolymer of PLLA and poly(oxyethylene) (PEO) or a triblock PLLA-PCL-PLLA copolymer as a third component. Optical microscopy revealed that the domain size of dispersed PCL domains is reduced by one order of magnitude in the presence of both copolymers. SEM confirmed the strong reduction in particle size upon the addition of the copolymers, with an indication of an enhanced emulsifying effect in the case of the PLLA-PEO copolymer. These results are analyzed on the basis of solubility parameters of the blend components. Optical micrograph of M3EG2 blend melt quenched at 125,°C. [source] Investigation of the Reaction Between Benzophenone and Trimethylaluminium: A Source of Novel Aluminic Activator for Single-site Olefin Polymerization CatalystsMACROMOLECULAR SYMPOSIA, Issue 1 2005Thomas Dalet Abstract The reaction between benzophenone and TMA was investigated in details at 20,°C for different TMA/benzophenone (r) ratios. For r,=,2, a heterodimer µ-(1,1-diphenylethoxy)-µ-methyl-tetramethyldialuminium (B) is only formed. The latter was found able to activate MeDIP(2,6-iPrPh)2FeCl2 catalyst towards ethylene polymerization. Such catalytic system leads to the formation of high molar mass polyethylene with a broad molar mass distribution, without the presence of oligomers, that is attributed to a strong reduction of the transfer reaction to TMA. [source] A role for the Escherichia coli H-NS-like protein StpA in OmpF porin expression through modulation of micF RNA stabilityMOLECULAR MICROBIOLOGY, Issue 1 2000Padraig Deighan When a wild-type strain of Escherichia coli and its stpA, hns and stpA hns mutant derivatives were compared by two-dimensional protein gel electrophoresis, the levels of expression of several proteins were found to vary. One of these was identified as the outer membrane porin protein, OmpF. In the stpA hns double mutant, the level of OmpF was downregulated dramatically, whereas in hns or stpA single mutants, it was affected only slightly. Transcription from the ompF promoter was reduced by 64% in the double mutant; however, the level of ompF mRNA was reduced by 96%. This post-transcriptional expression was found to result from a strong reduction in the half-life of ompF message in the double mutant. The micF antisense RNA was shown to be involved in OmpF regulation by StpA using a strain deleted for micF. Moreover, micF antisense RNA accumulated considerably in an stpA hns background. Transcriptional data from a micF,lacZ fusion and measurements of micF RNA half-life confirmed that this was caused by transcriptional derepression of micF as a result of the hns lesion and increased micF RNA stability due to the absence of StpA (a known RNA chaperone). These data suggest a novel facet to the regulation of OmpF expression, namely destabilization of micF RNA by StpA. [source] Influence of genetic variation in CYP3A4 and ABCB1 on dose decrease or switching during simvastatin and atorvastatin therapy,PHARMACOEPIDEMIOLOGY AND DRUG SAFETY, Issue 1 2010Matthijs L. Becker PharmD Abstract Purpose Simvastatin and atorvastatin are metabolized by the CYP3A4 enzyme and transported by the ABCB1 transporter. We studied whether the polymorphism CYP3A4*1B and the polymorphisms C1236T, G2677A/T and C3435T in the ABCB1 gene were associated with a decrease of the prescribed dose or a switch to another cholesterol lowering drug during simvastatin and atorvastatin therapy. These events may indicate that statin plasma levels were too high and resulted in an adverse drug reaction or a too strong reduction in cholesterol level. Methods We identified 1239 incident simvastatin and atorvastatin users in the Rotterdam Study, a population-based cohort study. Associations between the polymorphisms in the CYP3A4 and ABCB1 gene and the time to a decrease in dose or a switch to another cholesterol lowering drug were studied using Cox proportional hazards. Results Simvastatin and atorvastatin users with the CYP3A4*1B variant G allele had a lower risk (HR 0.46; 95%CI 0.24,0.90) for these events than users with the wild-type AA genotype. No significant associations were found for the ABCB1 polymorphisms. The association with the CYP3A4*1B polymorphism was found in women (HR 0.33; 95%CI 0.12,0.89) and was non-significant in men (HR 0.69 95%CI 0.28,1.70). This association was stronger in patients with the ABCB1 3435T variant allele versus the G allele. Conclusion In simvastatin and atorvastatin users, the CYP3A4*1B G allele is associated with a lower risk of elevated statin plasma levels, particularly in women and in users with the ABCB1 3435T variant allele. Copyright © 2009 John Wiley & Sons, Ltd. [source] Growth of GaN quantum dots on nonpolar A -plane SiC by molecular-beam epitaxyPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 15 2006S. Founta Abstract We report on A -plane GaN quantum dots in AlN, grown on A -plane 6H SiC substrates by plasma-assisted molecular-beam epitaxy. AFM imaging revealed a strong alignment of the dots along the [100] direction that we correlated with the anisotropic morphology of the AlN buffer layer. A vertical correlation of these dots was evidenced by high resolution transmission electron microscopy on superlattice samples with an AlN spacer thickness of 5 nm. Time-resolved spectroscopy performed on both C -plane and A -plane samples revealed much shorter radiative lifetimes for the A -plane dots, indicating a strong reduction of the internal electric field with respect to the one present in their C -plane counterparts. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Defects and structure of µc-SiOx:H deposited by PECVDPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3-4 2010Lihong Xiao Abstract Electronic transport and paramagnetic defects detected by Electron Spin Resonance (ESR) in both intrinsic and Two-dimensional phononless VRH conduction in arrays of Ge/Si quantum dotsPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2004A. I. Yakimov Abstract We report measurements of a two-dimensional variable-range hopping conductance in delta-doped Ge/Si heterostructures with a layer of Ge nanometer-scale quantum dots. We found that the conductance , vs. temperature T follows the Efros-Shklovskii behavior , = ,0 exp[,(T0/T )1/2] with the temperatureindependent prefactor ,0 , e2/h. A strong reduction of the measured value of T0 from that calculated for single-particle hopping was observed. All these results provide a manifestation of interaction-driven many-electron correlated hopping in dense arrays of quantum dots. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] The BOS loci of Arabidopsis are required for resistance to Botrytis cinerea infectionTHE PLANT JOURNAL, Issue 4 2004Paola Veronese Summary Three Botrytis -susceptible mutants bos2, bos3, and bos4 which define independent and novel genetic loci required for Arabidopsis resistance to Botrytis cinerea were isolated. The bos2 mutant is susceptible to B. cinerea but retains wild-type levels of resistance to other pathogens tested, indicative of a defect in a response pathway more specific to B. cinerea. The bos3 and bos4 mutants also show increased susceptibility to Alternaria brassicicola, another necrotrophic pathogen, suggesting a broader role for these loci in resistance. bos4 shows the broadest range of effects on resistance, being more susceptible to avirulent strain of Pseudomonas syringae pv. tomato. Interestingly, bos3 is more resistant than wild-type plants to virulent strains of the biotrophic pathogen Peronospora parasitica and the bacterial pathogen P. syringae pv. tomato. The Pathogenesis Related gene 1 (PR-1), a molecular marker of the salicylic acid (SA)-dependent resistance pathway, shows a wild-type pattern of expression in bos2, while in bos3 this gene was expressed at elevated levels, both constitutively and in response to pathogen challenge. In bos4 plants, PR-1 expression was reduced compared with wild type in response to B. cinerea and SA. In bos3, the mutant most susceptible to B. cinerea and with the highest expression of PR-1, removal of SA resulted in reduced PR-1 expression but no change to the B. cinerea response. Expression of the plant defensin gene PDF1-2 was generally lower in bos mutants compared with wild-type plants, with a particularly strong reduction in bos3. Production of the phytoalexin camalexin is another well-characterized plant defense response. The bos2 and bos4 mutants accumulate reduced levels of camalexin whereas bos3 accumulates significantly higher levels of camalexin than wild-type plants in response to B. cinerea. The BOS2, BOS3, and BOS4 loci may affect camalexin levels and responsiveness to ethylene and jasmonate. The three new mutants appear to mediate disease responses through mechanisms independent of the previously described BOS1 gene. Based on the differences in the phenotypes of the bos mutants, it appears that they affect different points in defense response pathways. [source] Role of allatostatin-like factors from the brain of Tenebrio molitor females,ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 4 2009O. Wasielewski Abstract The effect of brain extract from females of freshly emerged Tenebrio molitor on ovary, oocyte development, total protein content of hemolymph, and ovary was studied in 4-day-old adult mealworm females. Injections of extracts of 2-brain equivalents into intact (unligatured) Tenebrio females did not affect ovarian and oocyte development. Injections of ligated females, however, with 2-brain equivalents on day 1 and 2 after adult emergence strongly inhibited ovarian growth and oocyte development. At day 4, ligated and injected females did not develop their ovaries and pre-vitellogenic oocytes were not found. The changes in ovarian development correlated with an increase in the concentration of soluble proteins in the hemolymph as compared with the saline-injected controls. Additionally, a strong reduction of total protein content in ovarian tissue was observed. Reverse phase HPLC separation of a methanolic brain extract of T. molitor females showed that fraction 5 has a similar retention time to synthetic cockroach allatostatin. Fraction 5 was eluted at 12.88,min, which was closest to the internal standard Dippu-AST I, which eluted at 12.77,min. An ELISA of fraction 5 from the methanolic brain extract using antibodies against allatostatins Grybi-AST A1 and Grybi-AST B1 from cricket Gryllus bimaculatus showed that fraction 5 cross-reacted with Grybi-AST A1 antibodies. The cross-reactivity was similar to the synthetic allatostatin from D. punctata, which was used as a positive control. These observations demonstrate a possible role for allatostatin-like brain factor(s) in regulating the reproductive cycle of Tenebrio molitor. © 2009 Wiley Periodicals, Inc. [source] Trade-off between immune stimulation and expression of storage protein genesARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 2 2009Anete P. Lourenēo Abstract Proteins stored in insect hemolymph may serve as a source of amino acids and energy for metabolism and development. The expression of the main storage proteins was assessed in bacterial-challenged honey bees using real-time (RT)-PCR and Western blot. After ensuring that the immune system had been activated by measuring the ensuing expression of the innate immune response genes, defensin-1 (def-1) and prophenoloxidase (proPO), we verified the expression of four genes encoding storage proteins. The levels of vitellogenin (vg) mRNA and of the respective protein were significantly lowered in bees injected with bacteria or water only (injury). An equivalent response was observed in orally-infected bees. The levels of apolipophorin II/I (apoLp-II/I) and hexamerin (hex 70a) mRNAs did not significantly change, but levels of Hex 70a protein subunit showed a substantial decay after bacterial challenge or injury. Infection also caused a strong reduction in the levels of apoLp-III transcripts. Our findings are consistent with a down-regulation of the expression and accumulation of storage proteins as a consequence of activation of the immune system, suggesting that this phenomenon represents a strategy to redirect resources to combat injury or infection. © 2009 Wiley Periodicals, Inc. [source] Platelet CD62 expression and PDGFAB secretion in patients undergoing PTCA and treatment with abciximabBRITISH JOURNAL OF CLINICAL PHARMACOLOGY, Issue 6 2001J. Graff Aims, To investigate a correlation of the platelet activation marker CD62 and secretion of the growth factor PDGF from platelets in coronary patients under therapy with the GPIIb/IIIa-inhibitor abciximab. Methods, Flow cytometric assessment of fibrinogen binding (GPIIb/IIIa-binding site) and CD62 expression, as well as PDGF release of human platelets (immunoassay) and platelet aggregation with 20 µm ADP and 2 µg ml,1 collagen were evaluated in nine patients with stable coronary artery disease. Patients were undergoing elective balloon angioplasty and were treated with aspirin (100 mg day,1), heparin (ACT < 220 s) and abciximab (bolus and infusion over 12 h). Blood samples were obtained before initiation of abciximab therapy (under aspirin and heparin) (I), 3 h after angioplasty under abciximab (II) and 12 h after termination of abciximab infusion (III). Results, Compared with sample I before abciximab therapy, fibrinogen binding was reduced to 37% (± 34 s.d., P < 0.05) (II) and 55% (± 40 s.d., P < 0.05) (III). Reduced fibrinogen binding also led to a significant reduction of the aggregation response to ADP (down to 37% ± 20) and collagen (down to 0%). Mean fluorescence intensity of CD62-expression was 78 units (± 20 s.d.) (I), 72 units (± 14 s.d.) (II) and 64 units (± 12 s.d., P < 0.05) (III). PDGF release from isolated, washed platelets was 99 (± 33 s.d.) ng/109 platelets at (I), 82 (± 31 s.d.) ng/109 platelets and 96 (± 30 s.d.) ng/109 platelets. Conclusions, The results indicate that despite a strong reduction of GPIIb/IIIa-binding and platelet aggregation, CD62 as a marker of platelet secretion and the secretion product PDGF were only slightly reduced under abciximab treatment. No direct correlation between CD62 expression and PDGF release could be demonstrated. [source] Torsional Barriers in Aromatic Molecular Clusters as Probe of the Electronic Properties of the ChromophoreCHEMPHYSCHEM, Issue 11 2004Christoph Jacoby Dr. Abstract We present a computer program that is capable of fitting n -fold torsional barriers Vn(n=2,6) and torsional constants F simultaneously to high- and low-resolution spectroscopic data of different isotopomeric internal rotors. The program has been utilized to fit independently barriers and torsional constants for both electronic states of several aromatic clusters. The constant F of the ammonia moiety in the phenol,ammonia cluster is shown to decrease upon electronic excitation, thus imaging the formation of a hydrogen-bonded complex between the phenoxy radical and the NH4 radical in the excited state. In contrast, for the naphthol,ammonia 1:1 clusters no change of F of ammonia could be found. For phenol,methanol cluster we found a decrease of F upon excitation which points to a stronger hydrogen bond between phenol and methanol in the excited state. A strong reduction of the torsional barrier upon excitation points to the formation of a methoxonium radical in a similar photoreaction as in phenol,ammonia cluster. For the phenol,water system we postulate the same mechanism, a photoreaction, which leads to a translocated hydrogen atom in the S1 state what can be deduced from the change of the torsional constant upon electronic excitation. [source] Detection and distribution of probiotic Escherichia coli Nissle 1917 clones in swine herds in GermanyJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2006S. Kleta Abstract Aims:, To verify the presence of Escherichia coli Nissle 1917 as a natural isolate in swine and to characterize in vitro probiotic properties as well as in vivo persistence in a feeding experiment. Methods and Results:, During studies on the intestinal microflora of pigs, we isolated E. coli Nissle 1917 sporadically from a pig population over a period of 1 year. The identity of the isolates as E. coli Nissle 1917 was verified by serotyping, Nissle-specific PCR, macrorestriction analysis (pulsed field gel electrophoresis) and the determination of in vitro probiotic properties in invasion and adhesion assays using a porcine intestinal epithelial cell line. Both the E. coli isolates and the E. coli Nissle 1917 strain showed strong reductions in adhesion of porcine enteropathogenic E. coli and invasion of Salmonella typhimurium with epithelial cells in vitro, with a probiotic effect. Screening of five epidemiologically unlinked swine farms and two wild boar groups showed one farm positive for E. coli Nissle 1917. A feeding experiment with four piglets showed viable E. coli Nissle 1917 in the intestine of three animals. Conclusions:, The results of this study suggest that the E. coli Nissle 1917 strain is already partially established in swine herds, but the colonization of individual animals is variable. Significance and Impact of the Study:, We report natural, long-term colonization and transmission of the probiotic E. coli Nissle 1917 strain in a swine herd, characterized individual persistence and colonization properties in swine and established an in vitro porcine intestinal epithelial cell model of probiotic action. The results of this study would have implications in the use of this strain as a probiotic in swine and contribute to a better understanding of the individual nature of intestinal bacterial persistence and establishment. [source]
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