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Kinds of C3 Terms modified by C3 Selected AbstractsAn audit of the accuracy of fine needle aspiration using a liquid-based cytology system in the setting of a rapid access breast clinicCYTOPATHOLOGY, Issue 6 2002L. Joseph We have assessed the effectiveness and accuracy of reporting fine needle aspirates of the breast (FNAB) using a liquid-based cytology (LBC) system (the Cytospin® method) in the pressure situation of a rapid access clinic (RAC). We have reviewed every case from the RAC from June 1997 to February 2001 inclusive. There were 1322 cases, which accounted for 26% of the total FNAB received in our department over the period. There were 323 cancers and 999 benign cases in the group. The inadequate/nondiagnostic rate (C1) was 18%. The absolute sensitivity, including C1 cases, was 73% with the complete sensitivity being 90%. The groups of ,atypical, probably benign' (C3) and ,suspicious, probably malignant' (C4) accounted for a total of 6.2%. There were 28 false negative cases and 1 false positive case (a borderline phyllodes tumour). Comparing our results with the standards recommended by the NHSBSP has shown that the diagnosis of FNAB using this LBC method is feasible, accurate and reliable even in the pressure situation of a RAC. [source] An audit of ,equivocal' (C3) and ,suspicious' (C4) categories in fine needle aspiration cytology of the breastCYTOPATHOLOGY, Issue 4 2001R. A. Deb An audit of ,equivocal' (C3) and ,suspicious' (C4) categories in fine needle aspiration cytology of the breast We have audited the frequency of use and outcome of the ,equivocal/atypia probably benign' (C3) and ,suspicious of malignancy' (C4) category for breast cytology in our Unit. A total of 14 935 cytological specimens were reported by at least one of the three pathologists with a special interest in breast pathology, according to five categories of the NHSBSP guidelines for cytology reporting, 1992; 3.7% (555 cases) and 3.9% (587 cases) of cases were classified as equivocal (C3) and suspicious (C4), respectively, giving a total rate (C3 + C4) of 7.6%. Of the C3 cases, 68% were subsequently benign and 32% were malignant. Of the C4 cases, 19% were subsequently benign and 81% malignant. The commonest benign lesions in both categories were fibroadenomas (7.6% of C3 and 19.8% of C4), fibrocystic change (14.3% of C3 and 12.5% of C4), radial scars (6.2% of C3 and 10.4% of C4) and papillomas (6.2% of C3 and 6.3% of C4). Of the malignant lesions (particularly those classified as C3), a high proportion were low grade or special type cancers. The categories of atypia probably benign (C3) and suspicious of malignancy (C4) in breast cytology provide a strategy for classification of problematic or uncertain cases; this maintains the predictive value of the benign (C2) and malignant (C5) categories, and allows separation of these difficult cases into clinically useful groups with differing probabilities of malignancy. [source] RhoA/ROCK and Cdc42 regulate cell-cell contact and N-cadherin protein level during neurodetermination of P19 embryonal stem cellsDEVELOPMENTAL NEUROBIOLOGY, Issue 3 2004Isabel Laplante Abstract RhoGTPases regulate actin-based signaling cascades and cellular contacts. In neurogenesis, their action modulates cell migration, neuritogenesis, and synaptogenesis. Murine P19 embryonal stem cells differentiate to neurons upon aggregation in the presence of retinoic acid, and we previously showed that RhoA and Cdc42 RhoGTPases are sequentially up-regulated during neuroinduction, suggesting a role at this very early developmental stage. In this work, incubation of differentiating P19 cells with C3 toxin resulted in decreased aggregate cohesion and cadherin protein level. In contrast, C3 effects were not observed in cells overexpressing recombinant dominant active RhoA. On the other hand, C3 did not affect cadherin in uninduced cells and their postmitotic neuronal derivatives, respectively expressing E- and N-cadherin. RhoA is thus influential on cell aggregation and cadherin expression during a sensitive time window that corresponds to the switch of E- to N-cadherin. Cell treatment with Y27632 inhibitor of Rho-associated-kinase ROCK, or advanced overexpression of Cdc42 by gene transfer of a constitutively active form of the protein reproduced C3 effects. RhoA-antisense RNA also reduced cadherin level and the size of cell aggregates, and increased the generation of fibroblast-like cells relative to neurons following neuroinduction. Colchicin, a microtubule disrupter, but not cytochalasin B actin poison, importantly decreased cadherin in neurodifferentiating cells. Overall, our results indicate that the RhoA/ROCK pathway regulates cadherin protein level and cell-cell interactions during neurodetermination, with an impact on the efficiency of the process. The effect on cadherin seems to involve microtubules. The importance of correct timing of RhoA and Cdc42 functional expression in neurogenesis is also raised. © 2004 Wiley Periodicals, Inc. J Neurobiol 60: 289,307, 2004 [source] The Prestige oil spill.ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 9 2005Abstract In vitro biodegradation of the Prestige heavy fuel oil has been carried out using two microbial consortia obtained by enrichment in different substrates to simulate its environmental fate and potential utility for bioremediation. Different conditions, such as incubation time (i.e., 20 or 40 d), oil weathering, and addition of an oleophilic fertilizer (S200), were evaluated. Weathering slowed down the degradation of the fuel oil, probably because of the loss of lower and more labile components, but the addition of S200 enhanced significantly the extension of the biodegradation. n -Alkanes, alkylcyclohexanes, alkylbenzenes, and the two- to three-ring polycyclic aromatic hydrocarbons (PAHs) were degraded in 20 or 40 d of incubation of the original oil, whereas the biodegradation efficiency decreased for higher PAHs and with the increase of alkylation. Molecular markers were degraded according to the following sequence: Acyclic isoprenoids < diasteranes < C27 -steranes < ,,-steranes < homohopanes < monoaromatic steranes < triaromatic steranes. Isomeric selectivity was observed within the C1 - and C2 -phenanthrenes, dibenzothiophenes, pyrenes, and chrysenes, providing source and weathering indices for the characterization of the heavy oil spill. Acyclic isoprenoids, C27 -steranes, C1 - and C2 -naphthalenes, phenanthrenes, and dibenzothiophenes were degraded completely when S200 was used. The ratios of the C2 - and C3 -alkyl homologues of fluoranthene/pyrene and chrysene/benzo[a]anthracene are proposed as source ratios in moderately degraded oils. The 4-methylpyrene and 3-methylchrysene were refractory enough to serve as conserved internal markers in assessing the degradation of the aromatic fraction in a manner similar to that of hopane, as used for the aliphatic fraction. [source] The effect of rising and sitting trot on back movements and head-neck position of the horseEQUINE VETERINARY JOURNAL, Issue 5 2009P. de COCQ Summary Reason for performing study: During trot, the rider can either rise from the saddle during every stride or remain seated. Rising trot is used frequently because it is widely assumed that it decreases the loading of the equine back. This has, however, not been demonstrated in an objective study. Objective: To determine the effects of rising and sitting trot on the movements of the horse. Hypothesis: Sitting trot has more extending effect on the horse's back than rising trot and also results in a higher head and neck position. Methods: Twelve horses and one rider were used. Kinematic data were captured at trot during over ground locomotion under 3 conditions: unloaded, rising trot and sitting trot. Back movements were calculated using a previously described method with a correction for trunk position. Head-neck position was expressed as extension and flexion of C1, C3 and C6, and vertical displacement of C1 and the bit. Results: Sitting trot had an overall extending effect on the back of horses when compared to the unloaded situation. In rising trot: the maximal flexion of the back was similar to the unloaded situation, while the maximal extension was similar to sitting trot; lateral bending of the back was larger than during the unloaded situation and sitting trot; and the horses held their heads lower than in the other conditions. The angle of C6 was more flexed in rising than in sitting trot. Conclusions and clinical relevance: The back movement during rising trot showed characteristics of both sitting trot and the unloaded condition. As the same maximal extension of the back is reached during rising and sitting trot, there is no reason to believe that rising trot was less challenging for the back. [source] Clinical findings, diagnosis, prevalence and predisposing factors for lameness localised to the middle carpal joint in young Standardbred racehorsesEQUINE VETERINARY JOURNAL, Issue 2 2006C. M. Steel Summary Reasons for performing study: Lameness related to the middle carpal joint (MCJ) occurs in up to 30% of young Standardbred horses in race training and the incidence increase with radiographic severity of third carpal bone (C3) sclerosis on DPr-DDIO (skyline) view of the carpus. Factors predisposing horses to carpal injury have not been well investigated. Objectives: To determine the importance of MCJ lameness as a cause of wastage in young Standardbred racehorses, stage of training at which it occurs and predisposing factors, and to describe clinical findings and diagnosis. Methods: Standardbred horses (n = 114) entering their first year of race training were examined at approximately 3-month intervals over 12,18 months. For 87 of the horses, a training diary was available and these horses were trained at 3 different stables, each using a different exercise regime. At each examination, forelimb conformation, MCJ effusion, MCJ lameness and radiographic findings were graded, and training history and reasons for lost training days recorded. Nuclear scintigraphy and exploratory arthroscopy were performed on a limited selection of horses. Results for horses that developed MCJ lameness during the study period were compared statistically with results for horses that did not. Results: Carpal lameness occurred in 28% of horses and was present in 56% with forelimb lameness. In most cases lameness was mild, bilateral and with little or no MCJ effusion and was attributed to subchondral bone pain associated with radiographic evidence of C3 sclerosis. Carpal lameness was the most common reason for >1 month's rest during the study period. It occurred at any stage of training but, in most cases, some speed training had begun. Of the variables studied, poor forelimb conformation and more intense speed training were predisposing factors. Conclusions and potential relevance: The information gained should assist in making recommendations regarding training young Standardbreds to reduce the incidence of MCJ lameness. However, further investigations to determine the optimal training regime are warranted. [source] C5a anaphylatoxin as a product of complement activation up-regulates the complement inhibitory factor H in rat Kupffer cellsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 11 2004Gerald Schlaf Abstract The 155-kDa complement regulator factor H (FH) is the predominant soluble regulatory protein of the complement system. It acts as a cofactor for the factor I-mediated conversion of the component C3b to iC3b, competes with factor B for a binding site on C3b and C3(H2O) and promotes the dissociation of the C3bBb complex. The primary site of synthesis is the liver, i.e. FH-specific mRNA and protein were identified in both hepatocytes (HC) and Kupffer cells (KC). Previous studies in rat primary HC and KC had shown that the proinflammatory cytokine IFN-, influences the balance between activation and inhibition of the complement system through up-regulation of the inhibitory FH. In this study we show that C5a, as a product of complement activation, stimulates the expression of FH-specific mRNA and protein in KC and thus induces a negative feedback. Quantitative-competitive RT-PCR showed an approximate threefold C5a-induced up-regulation of FH. ELISA analyses revealed a corresponding increase in FH protein in the supernatants of KC. The up-regulation of FH was completely inhibited by the C5a-blocking monoclonal antibody 6-9F. Furthermore, an involvement of LPS and IFN-, was excluded, which strongly indicates a direct effect of C5a on the expression of FH in KC. [source] Complement activation by both classical and alternative pathways is critical for the effector phase of arthritisEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 4 2004Albert Hietala Abstract To analyze the role of the classical and alternative pathways of complement activation in the effector phase of arthritis, we have induced arthritis in C3- and factor,B (FB)-deficient (C3,/, and FB,/,) DBA/1J mice using well-defined monoclonal IgG2b and IgG2a antibodies to type,II collagen. In control DBA/1J mice, severe swelling of the joints, destruction of cartilage and erosion of bone developed very rapidly with a 100% incidence and a peak on days,7,10. Although 75% of C3,/, mice developed arthritis, the clinical severity was very mild and the onset was delayed. Severity of arthritis in FB,/, mice ranked intermediate in comparison with C3,/, and control mice with an incidence of 100%. Immunohistochemical analysis of the inflamed joints demonstrated substantial reduction in macrophage and neutrophilic leukocyte infiltration in both C3,/, and FB,/, mice, thereby confirming the clinical findings. We conclude that both the classical and the alternative pathways of complement activation are involved in the effector phase of arthritis. [source] Antibody-mediated bacterial clearance from the lower respiratory tract of mice requires complement component C3EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 1 2004Elizabeth Abstract To assess the contribution of complement to respiratory immunity in the context of a natural bacterial infection, we used mice genetically deficient in complement components and the murine pathogen Bordetella bronchiseptica. Complement component C3 was not required for the control of bacterial infection or for the generation of infection-induced protective immunity. However, C3-deficient (C3,/,) mice were severely defective, compared to wild type, in vaccine-induced protective immunity. Adoptively transferred immune serum from convalescent wild-type or C3,/, animals rapidly cleared B.,bronchiseptica from the lungs of wild-type mice but did not affect its growth in C3,/, mice, indicating that the defect is not in the generation of protective immunity, but in its function. Immune serum was effective in C5-deficient mice but had little effect in the lungs of mice lacking either Fc, receptors (Fc,R) or CR3, suggesting bacterial clearance is not via direct complement-mediated lysis. Together, these data indicate that complement is required for antibody-mediated clearance of Bordetella and suggest the mechanism involves C3 opsonization of bacteria for phagocytosis that is both CR3- and Fc,R-dependent. [source] Complement receptors type 1 (CR1, CD35) and 2 (CR2, CD21) cooperate in the binding of hydrolyzed complement factor 3 (C3i) to human B lymphocytesEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 12 2003Graham, Quinton Leslie, Robert Abstract The C3b-binding receptor, CR1/CD35, supports CR2/CD21-mediated activation of complement by human B lymphocytes, possibly by associating with CR2 to promote or stabilize the binding of hydrolyzed C3 (C3i), the primary component of the AP convertase, C3i-Bb. To evaluate this hypothesis, we examined the uptake kinetics and binding equilibria for C3i dimer interaction with human blood cells in the absence and presence of CR1- and CR2-blocking mAb. C3i displayed dual uptake kinetics to B lymphocytes, comprising of rapid binding to CR1 and slower binding to CR2. The forward rate constants (k1) for CR1 and CR2, operating independently, differed ca. 9-fold (k1=193±9.4 and 22.2±6.0×103,M,1s,1, respectively). Equilibrium binding of C3i to B lymphocytes was also complex, varying in strength by ca. 13-fold over the C3i concentration range examined. The maximum association constant (Ka,,max=109±27.2×107,l/mole) was ca. 9- and 6-fold greater, respectively, than those for CR1 or CR2 acting alone (Ka=13.2±5.3 and 18.5±3.5×107,l/mole). The high avidity of the CR1-CR2 complex for C3i is consistent with its rates of C3i uptake and release being determined by CR1 and CR2, respectively. [source] Scandium-Catalyzed Polymerization of CH3(CH2)nCH=CH2 (n = 0,4): Remarkable Activity and Tacticity ControlEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 7 2009Benjamin D. Ward Abstract The C3 -symmetric trisoxazoline-supported scandium complex [Sc(iPr-trisox)(CH2SiMe3)3] (2) is highly active in the stereospecific polymerization of propene, 1-butene, 1-pentene, 1-hexene and 1-heptene, when activated with two equivalents of [Ph3C][B(C6F5)4]. The polymers thus produced were found to possess narrow molecular weight distributions and high levels of tacticity control (up to 99,% mmmm). Some insight into the nature of the active species was obtained by 1H, 13C and 29Si NMR experiments. In particular, the formation of two equivalents of Ph3CCH2SiMe3 at ambient temperature was observed alongside a C3 -symmetric scandium complex tentatively assigned as the dication [Sc(iPr-trisox)(CH2SiMe3)]2+.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] [Bis(guanidine)]zinc Complexes and Their Application in Lactide PolymerisationEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 36 2007Janna Börner Abstract The bis(guanidine)-stabilised zinc complexes [N1,N2 -bis(1,3-dimethylimidazolidin-2-ylidene)ethane-1,2-diamine]dichloridozinc(II), [Zn(DMEG2e)Cl2] (C1), diacetato[N1,N2 -bis(1,3-dimethylimidazolidin-2-ylidene)ethane-1,2-diamine]zinc(II),[Zn(DMEG2e)(CH3COO)2] (C2), and bis[N1,N2 -bis(1,3-dimethylimidazolidin-2-ylidene)ethane-1,2-diamine]zinc(II) bis(trifluoromethanesulfonate), [Zn(DMEG2e)2](CF3SO3)2 (C3), have been synthesised and completely characterised by means of X-ray structure analysis, NMR spectroscopy and mass spectrometry. These [bis(guanidine)]zinc complexes were investigated regarding their activity in the bulk polymerisation of D,L -lactide. It could be shown that these compounds are able to act as initiators for lactide polymerisation, and polylactides with molecular weights (Mw) of around 18000,59000 g/mol could be obtained. Variation of the reaction temperature revealed that the molecular weights decrease with increasing temperature. Additionally, the correlation of the intrinsic viscosity with the molecular weight demonstrates that the obtained polymers are linear and structurally homogeneous.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Synthesis of a Metallamacrocyclic Re(CO)3 Complex Using a Tridentate Bridging LigandEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 5 2004Thomas Brasey Abstract The reaction of [ReBr3(CO)3][NEt4]2 with 3-hydroxy-1,2,3-benzotriazine-4(3H)-one in the presence of base gave the ionic rhenium complex [ReBr(C7H4N3O2)(CO)3][NEt4] (2) which was crystallographically characterized. A neutral metallamacrocycle 3 was obtained upon abstraction of [NEt4]Br from complex 2. This complex cocrystallizes with an unusual C3 -symmetric [Ag(,2 -benzene)3(OH2)][BF4] complex as evidenced by single-crystal X-ray diffraction. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Event-related delta oscillatory responses of Alzheimer patientsEUROPEAN JOURNAL OF NEUROLOGY, Issue 6 2008G. Yener Background and purpose:, Alzheimer type of dementia (AD) is the most common neuropsychiatric morbidity in elderly individuals. Event-related oscillations (ERO) provide an useful tool for detecting subtle abnormalities of cognitive processes with high temporal resolution. Methods:, In the present report, event-related oscillations of patients with AD were analyzed by using a visual oddball paradigm. A total of 22 mild probable AD subjects according to NINCDS-ADRDA criteria and 20 age-, gender-, and education-matched healthy control subjects were compared. AD group consisted from 11 untreated patients and 11 patients treated with cholinesterase inhibitor. Oscillatory responses were recorded from 13 scalp electrodes. Results:, Significant differences in delta frequency range were seen between the groups by using repeated measures of anova analysis [F(9.120) = 2.228; P = 0.022]. Post-hoc analyses using Wilcoxon test showed that at mid- and left central regions, (Cz, C3) peak amplitudes of delta responses of healthy subjects were significantly higher than either group. Also cholinesterase inhibitors did not have effect on delta oscillatory responses. Conclusions:, Our findings imply that the delta oscillatory responses at central locations are highly instable in mild probable AD patients regardless of treatment when compared to the healthy aged controls. This study supports the importance of oscillatory event-related potentials for investigating AD brain dynamics. [source] Precise matching of olivo-cortical divergence and cortico-nuclear convergence between somatotopically corresponding areas in the medial C1 and medial C3 zones of the paravermal cerebellumEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2000R. Apps Abstract The paravermal cerebellar cortex contains three spatially separate zones (the C1, C3 and Y zones) which form a functionally coupled system involved in the control of voluntary limb movements. A series of ,modules' has been postulated, each defined by a set of olivary neurons with similar receptive fields, the cortical microzones innervated by these neurons and the group of deep cerebellar nuclear neurons upon which the microzones converge. A key feature of this modular organization is a correspondence between cortical input and output, irrespective of the zonal identity of the microzone. This was tested directly using a combined electrophysiological and bi-directional tracer technique in barbiturate-anaesthetized cats. During an initial operation, small injections of a mix of retrograde and anterograde tracer material (red beads combined with Fluoro-Ruby or green beads combined with biotinylated dextran amine or Fluoro-Emerald) were made into areas of the medial C1 and medial C3 zones in cerebellar lobule V characterized by olivo-cerebellar input from the ventral forelimb. The inferior olive and the deep cerebellar nuclei were then scrutinized for retrogradely labelled cells and anterogradely labelled axon terminals, respectively. For individual experiments, the degree of C1,C3 zone terminal field overlap in the nucleus interpositus anterior was plotted as a function of either the regional overlap of single-labelled cells or the proportion of double-labelled cells in the dorsal accessory olive. The results were highly positively correlated, indicating that cortico-nuclear convergence between parts of the two zones is in close proportion to the corresponding olivo-cerebellar divergence, entirely consistent with the modular hypothesis. [source] Short Synthesis of Orthogonally Protected 3,,12,-Diamino-5,-cholan-24-oic Acid, a Dipodal Steroid Scaffold for Combinatorial ChemistryEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 11 2007Dieter Verzele Abstract A short, practical, multigram-scale synthesis of C3,-NHAlloc, C12,-NHBoc-diamino-5,-cholan-24-oic acid 2 was developed, applying a new, straightforward synthetic strategy. Key features are the conservation of the carboxyl moiety at C24 during oxime reduction, the late differentiation between the C3 and C12 amino groups and the gradual separation of diastereomers during the synthesis. This orthogonally protected diamino steroid derivative can be used as starting point for the generation of steroid based dipodal peptide and non-peptide combinatorial libraries. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Effect of organic matter applications on 13C-NMR spectra of humic acids of soilEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 3 2008S. Dou Summary Much attention has been paid to improving soil fertility with organic matter (OM) application, which not only deals with organic wastes and protects the environment, but also maintains soil fertility and increases crop yields. Much research has also been on the effects of OM applications on the soil's physical, chemical and biological properties, but relatively less attention has been spent on humic substance (HS). In order to clarify the mechanism of improving soil fertility by applying OM, we analysed the changes of structural characteristics of humic acid (HA) from OM applications to soils by 13C-NMR, chemical analysis, thermal analysis, optical properties, IR and fluorescence spectroscopy. Samples of a brown soil (Paleudalf) and a paddy soil (an anthropogenic soil originating from Udifluvents) were collected from the plough layer of the long-term field experiment at Shenyang Agricultural University and Liaoning Provincial Alkali-Saline Soil Institute, respectively. Both field experiments included three treatments each: (i) brown soil, zero-treatment (CKbr) and two pig manure (PM) applications (O1 and O2) at annual rates of 0.9 t ha,1 and 1.8 t ha,1 of organic carbon, respectively; and (ii) paddy soil, zero-treatment (CKpad), pig manure (Op) and rice straw (Or) at annual rates of 2.62 t ha,1 and 1.43 t ha,1 of organic carbon, respectively. An incubation experiment was also carried out to test the field experiment on the brown soil, namely four treatments: zero-treatment (CKc), and three pig manure applications at rates of 30 g kg,1 (C1), 50 g kg,1 (C2) and 70 g kg,1 (C3), respectively. The total incubation was 180 days. The results indicated that number-average molecular weights (Mn), total acidity, aromaticity, excitation maximum wavelength (,Exmax), and the heat ratio of the high to moderate temperature exothermic regions (H3/H2) of the HA all decreased after OM application. The degree of activation (AD), the absorption intensity ratio of 2920 cm,1 to 1720 cm,1 in infrared spectra (IR2920/1720), alkyl C and O-alkyl C of the HA increased. The HA structure tended to become simpler and more aliphatic. [source] Properties of pyranose dehydrogenase purified from the litter-degrading fungus Agaricus xanthodermaFEBS JOURNAL, Issue 3 2007Magdalena Kujawa We purified an extracellular pyranose dehydrogenase (PDH) from the basidiomycete fungus Agaricus xanthoderma using ammonium sulfate fractionation and ion-exchange and hydrophobic interaction chromatography. The native enzyme is a monomeric glycoprotein (5% carbohydrate) containing a covalently bound FAD as its prosthetic group. The PDH polypeptide consists of 575 amino acids and has a molecular mass of 65 400 Da as determined by MALDI MS. On the basis of the primary structure of the mature protein, PDH is a member of the glucose,methanol,choline oxidoreductase family. We constructed a homology model of PDH using the 3D structure of glucose oxidase from Aspergillus niger as a template. This model suggests a novel type of bi-covalent flavinylation in PDH, 9- S -cysteinyl, 8-,- N3-histidyl FAD. The enzyme exhibits a broad sugar substrate tolerance, oxidizing structurally different aldopyranoses including monosaccharides and oligosaccharides as well as glycosides. Its preferred electron donor substrates are d -glucose, d -galactose, l -arabinose, and d -xylose. As shown by in situ NMR analysis, d -glucose and d -galactose are both oxidized at positions C2 and C3, yielding the corresponding didehydroaldoses (diketoaldoses) as the final reaction products. PDH shows no detectable activity with oxygen, and its reactivity towards electron acceptors is rather limited, reducing various substituted benzoquinones and complexed metal ions. The azino-bis-(3-ethylbenzthiazolin-6-sulfonic acid) cation radical and the ferricenium ion are the best electron acceptors, as judged by the catalytic efficiencies (kcat/Km). The enzyme may play a role in lignocellulose degradation. [source] Stereoselective biosynthesis of chloroarylpropane diols by the basidiomycete Bjerkandera adusta: exploring the roles of amino acids, pyruvate, glycerol and phenyl acetyl carbinolFEMS MICROBIOLOGY LETTERS, Issue 1 2003Peter James Silk Abstract Bjerkandera adusta produces many chlorometabolites including chlorinated anisyl metabolites (CAMs) and 1-arylpropane-1,2-diols (1, 2, 3, 4) as idiophasic metabolic products of l -phenylalanine. These diols are stereoselectively biosynthesized from a C7 -unit (benzylic, from l -phenylalanine) and a C2 -unit, of unknown origin, as predominantly erythro (1R,2S) enantiomers. Of the labeled amino acids tested as possible C2 -units, at the 4,10 mM level, none were found to efficiently label the 2,3-propane carbons of the diols. However, glycine (2- 13C), l -serine (2,3,3-d3) and l -methionine (methyl-d3) entered the biomethylation pathway. Neither pyruvate (2,3- 13C2), acetate (1,2- 13C2), acetaldehyde (d4) nor ethanol (ethyl-d5) labeled the 2,3-propane carbons of the diols at the 4,10 mM level. Pyruvate (2,3- 13C2) and l -serine (2,3,3-d3) (which also entered the biomethylation pathway) did, however, effectively label the 2,3-propane carbons of the ,-ketols and diols at the 40 mM level as evidenced by mass spectrometry. Glycerol (1,1,2,3,3-d5) also appeared to label one of the 2,3-propane carbons (ca. 5% as 2H2 in the C3 side chain) as suggested by mass spectrometric data and also entered the biomethylation pathway, likely via amino acid synthesis. Glycerol (through pyruvate), therefore, likely supplies C2 and C3 of the propane side chain with arylpropane diol biosynthesis. Incubation of B. adusta with synthetic [2- 2H1,2- 18O]-glycerol showed that neither 2H nor 18O were incorporated in the ,-ketols or diols. The oxygen atom on the C2 of the ketols/diols, therefore, does not appear to come from the oxygen atom on the C2 of glycerol. Glycerol, however, can readily form l -serine (which can then form pyruvate via PLP/serine dehydratase and involve transamination washing out the 18O label and providing the oxygen from water), and can then go on to label the C2 -unit. Labeled ,-ketol, phenyl acetyl carbinol (5) (PAC; ring-d5, 2,3- 13C2 propane) cultured with B. adusta leads to stereospecific reduction to the (1R,2S)-diol (6) (ring-d5 and 2,3- 13C2); in all other metabolites produced, the 2,3- 13C2 label is washed out. Incubation of the fungus with 4-fluorobenzaldehyde (13) produces a pooling of predominantly erythro (1R,2S) 1-(4,-fluorophenyl)-1,2-propane diol (18 as diacetate) (through the corresponding ,-ketols 16, 17). Blocking the para-position with fluorine thus appears to prevent ring oxygenation and also chlorination, forcing the conclusion that para-ring oxygenation precedes meta-chlorination. [source] Carbon sources of Amazonian fisheriesFISHERIES MANAGEMENT & ECOLOGY, Issue 4 2000E. Benedito-Cecilio Variation in the seasonal and spatial isotopic composition of plant C4 (aquatic macrophytes) and C3 (forest, C3 aquatic macrophytes and algae), and that of fish [Prochilodus nigricans Agassiz, Mylossoma duriventre (Cuvier), Colossoma macropomum (Cuvier), Semaprochilodus insignis (Schomburgk) and S. taeniurus Steindachner in the Amazon floodplain were analysed to test whether the fisheries deliver plant carbon to the population of Manaus in the same proportion as it is available in the floodplain. The contribution of C4 plants was significantly lower in 13C during the season of high water levels and increased toward the west of the basin. Mylossoma duriventre and C. macropomum changed ,13C levels, while the ,13C of P. nigricans and C. macropomum shifted spatially. The contribution of C4 to the fisheries yield was small. C3 plants (excluding phytoplankton) also contributed less than expected. This was explained by the importance of detritivores to the yield of the fisheries and the dependence of these species on algal carbon. [source] Life histories of Eucalanus bungii and Neocalanus cristatus (Copepoda: Calanoida) in the western subarctic Pacific OceanFISHERIES OCEANOGRAPHY, Issue 2004ATSUSHI TSUDA Abstract Life cycles of the large suspension-feeding copepods, Eucalanus bungii and Neocalanus cristatus were investigated by seasonal sampling in the western subarctic Pacific. Eucalanus bungii has a diapause from August to March at copepodite stages between copepodite 3 (C3) and C6 female. We propose that individuals with early birth dates are young of overwintering C5 and C6-females that develop to C4 in their birth year, while individuals with late birth dates are young of overwintering C4 that develop to C3 in their birth year. Thus, a majority of the population has annual generations alternating with biennial generations. Neocalanus cristatus showed life history almost identical to the population in the Alaskan gyre. Timing of the life cycle in N. cristatus is very close to that in the eastern subarctic gyre, but that of E. bungii is 2 months earlier than in the eastern subarctic. This difference is probably caused by the timing difference in the maximum primary production in the two areas and the plasticity of the life cycle strategy in E. bungii. [source] Can C4 plants contribute to aquatic food webs of subtropical streams?FRESHWATER BIOLOGY, Issue 6 2003Joanne E. Clapcott Summary 1. Recent stable isotope studies have revealed that C4 plants play a minor role in aquatic food webs, despite their often widespread distribution and production. We compared the breakdown of C3 (Eucalyptus) and C4 (Saccharum and Urochloa) plant litter in a small rain forest stream and used laboratory feeding experiments to determine their potential contribution to the aquatic food web. 2. All species of litter broke down at a fast rate in the stream, although Urochloa was significantly faster than Eucalyptus and Saccharum. This was consistent with the observed higher total organic nitrogen of Urochloa compared with the other two species. 3. The breakdown of Urochloa and Saccharum was, however, not associated with shredding invertebrates, which were poorly represented in leaf packs compared with the native Eucalyptus. The composition of the invertebrate fauna in packs of Urochloa quickly diverged from that of the other two species. 4. Feeding experiments using a common shredding aquatic insect Anisocentropus kirramus showed a distinct preference for Eucalyptus over both C4 species. Anisocentropus was observed to ingest C4 plant litter, particularly in the absence of other choices, and faecal material collected was clearly of C4 origin, as determined by stable isotope analysis. However, the stable carbon isotope values of the larvae did not shift away from their C3 signature in any of the feeding trials. 5. These data suggest that shredders avoid the consumption of C4 plants, in favour of native C3 species that appear to be of lower food quality (based on C : N ratios). Lower rates of consumption and lack of assimilation of C4 carbon also suggest that shredders may have a limited ability to process this material, even in the absence of alternative litter sources. Large scale clearing of forest and vegetation for C4 crops such as sugarcane will undoubtedly have important consequences for stream ecosystem function. [source] Carbon dioxide uptake, water relations and drought survival for Dudleya saxosa, the ,rock live-forever', growing in small soil volumesFUNCTIONAL ECOLOGY, Issue 4 2007P. S. NOBEL Summary 1Although many plants grow in rock crevices and other regions of small soil volume, including over 20 000 epiphytic and hemi-epiphytic species, analyses of the actual soil volume occupied, the water availability in that soil, the water-storage capacity in the shoots and underground organs, and the photosynthetic pathway utilized have rarely been combined. 2Dudleya saxosa (M.F. Jones) Britton and Rose (Crassulaceae), growing in the Sonoran Desert, has very shallow roots that occupied soil volumes averaging only 43 × 10,6 m3 per medium-sized plant. This volume of soil can hold about the same amount of water (10 g) as can be stored in the leaves, corm and roots combined (11 g), but at a sufficiently high water potential for transfer to the plant for less than 1 week after a substantial rainfall. 3About 80% of the net carbon dioxide uptake by D. saxosa over a 24-h period occurred during the daytime (C3) under wet conditions, the daily total decreasing by 34% and the pattern shifting to nocturnal net CO2 uptake (CAM) after 46 days' drought. Seventy-seven days' drought eliminated its daily net CO2 uptake. 4Stomatal frequency was only 67 mm,2 on the adaxial (upper) surface and twofold lower on the abaxial surface. The cuticle was thick, 34 µm for the adaxial surface. Leaves had 24 mesophyll cell layers, leading to a high mesophyll cell surface area per unit leaf area of 142. 5The three leaf anatomical features plus utilization of CAM increased net CO2 uptake per unit of water transpired, and helped D. saxosa thrive in a small soil volume, with the underground corm being a major supplier of water to the succulent leaves during 2.5 months of drought. The maximum water-holding capacity of the soil explored by the roots closely matched the maximum water-holding capacity of the plant, reflecting the conservative strategy used by D. saxosa in a stressful semi-arid environment. [source] C3,C4 composition and prior carbon dioxide treatment regulate the response of grassland carbon and water fluxes to carbon dioxideFUNCTIONAL ECOLOGY, Issue 1 2007H. W. POLLEY Summary 1Plants usually respond to carbon dioxide (CO2) enrichment by increasing photosynthesis and reducing transpiration, but these initial responses to CO2 may not be sustained. 2During May, July and October 2000, we measured the effects of temporarily increasing or decreasing CO2 concentration by 150,200 µmol mol,1 on daytime net ecosystem CO2 exchange (NEE) and water flux (evapotranspiration, ET) of C3,C4 grassland in central Texas, USA that had been exposed for three growing seasons to a CO2 gradient from 200 to 560 µmol mol,1. Grassland grown at subambient CO2 (< 365 µmol mol,1) was exposed for 2 days to an elevated CO2 gradient (> 365 µmol mol,1). Grassland grown at elevated CO2 was exposed for 2 days to a subambient gradient. Our objective was to determine whether growth CO2 affected the amount by which grassland NEE and ET responded to CO2 switching (sensitivity to CO2). 3The NEE per unit of leaf area was greater (16,20%) and ET was smaller (9,20%), on average, at the higher CO2 concentration during CO2 switching in May and July. The amount by which NEE increased at the higher CO2 level was smaller at elevated than subambient growth concentrations on both dates, but relationships between NEE response and growth CO2 were weak. Conversely, the effect of temporary CO2 change on ET did not depend on growth CO2. 4The ratio of NEE at high CO2 to NEE at low CO2 during CO2 change in July increased from 1·0 to 1·26 as the contribution of C3 cover to total cover increased from 26% to 96%. Conversely, in May, temporary CO2 enrichment reduced ET more in C4 - than C3 -dominated grassland. 5For this mesic grassland, sensitivity of NEE and ET to brief change in CO2 depended as much on the C3,C4 composition of vegetation as on physiological adjustments related to prior CO2 exposure. [source] Measuring natural abundance of 13C in respired CO2: variability and implications for non-invasive dietary analysisFUNCTIONAL ECOLOGY, Issue 6 2001S. E. PERKINS Summary 1,Three experiments were performed, using laboratory mice (Mus musculus) as a model species, to evaluate the potential of using measurements of carbon isotope ratios in expired CO2 for tracing diets. 2,Breath 13C signatures of mice fed a constant diet (,21·4, ± 0·35) reflected their diet, but were depleted by on average ,5·7,. Body mass, sex and age were independent and significant factors correlated with the variability of 13C enrichment in respired CO2. 3,Breath 13C signatures from starved mice (7 h) were lower than unstarved mice by 2·0,. Subsequently when starved mice were fed a small meal of a new diet, breath 13C signatures approached those of the new diets within 15 min, returning to preingestion levels after 105 min. 4,After a permanent diet switch 13C values of breath were not asymptotic within 6 days, possibly because of use of fat reserves during the daytime carrying an isotopic memory of the previous diet. Hence, individual breath 13C signatures may vary according to nutritive state and previous dietary history. 5,Interindividual variability was measured at 3·3,. The implications are that large samples of individuals will be required to distinguish between diets of different populations where the isotopic difference between their diets was small , for example, that expected between herbivorous and carnivorous diets. However, breath would be suitable for distinguishing between dietary intakes of individuals for food types that are isotopically more distinct , such as between C3 and C4 plants. [source] A QSAR analysis of toxicity of Aconitum alkaloidsFUNDAMENTAL & CLINICAL PHARMACOLOGY, Issue 6 2004Angélica M. Bello-Ramírez Abstract Biological activity of Aconitum alkaloids may be related to their toxicity rather than to a specific pharmacological action. A Quantitative structure-activity relationships (QSAR) analysis was performed on the following two groups of alkaloids: compounds with an aroyl/aroyloxy group at R14 position (yunaconitine, bulleyaconitine, aconitine, beiwutine, nagarine, 3-acetyl aconitine, and penduline), and compounds with the aroyloxy group at R4 position (N -deacetyllappaconitine, lappaconitine, ranaconitine, N -deacetylfinaconitine, N -deacetylranaconitine). The LD50 (,mol/kg) of the 12 alkaloids were obtained from the literature. LD50 was significantly lower in group 1 than in group 2. The steric and core,core repulsion energies were significantly higher in group 1. The total energy and heat of formation and electronic energies were significantly lower in group 1. The reactivity index of N, C1,, C4, and C6, were similar between groups. The reactivity index of C2, was significantly higher and the reactivity index of C3, and C5, were significantly lower in group 1. Log P and pKa were similar between groups. Molecular weight was significantly higher in group 1. A significant linear relationship was observed between log LD50 and either analgesic log ED50 or local anesthetic log ED50. The LD50/analgesic ED50 obtained from average values was 5.9 for group 1 and 5.0 for group 2. However, the LD50/local anesthetic ED50 was 40.4 and 318, respectively. The study supports that the analgesic effects of these alkaloids are secondary to their toxic effects whereas alkaloids from group 2 are susceptible to be further studied as local anesthetic agents. [source] Complement and its implications in cardiac ischemia/reperfusion: strategies to inhibit complementFUNDAMENTAL & CLINICAL PHARMACOLOGY, Issue 5 2001Tiphaine Monsinjon Although reperfusion of the ischemic myocardium is an absolute necessity to salvage tissue from eventual death, it is also associated with pathologic changes that represent either an acceleration of processes initiated during ischemia or new pathophysiological changes that were initiated after reperfusion. This so-called ,reperfusion injury' is accompanied by a marked inflammatory reaction, which contributes to tissue injury. In addition to the well known role of oxygen free radicals and white blood cells, activation of the complement system probably represents one of the major contributors of the inflammatory reaction upon reperfusion. The complement may be activated through three different pathways: the classical, the alternative, and the lectin pathway. During reperfusion, complement may be activated by exposure to intracellular components such as mitochondrial membranes or intermediate filaments. Two elements of the activated complement contribute directly or indirectly to damages: anaphylatoxins (C3a and C5a) and the membrane attack complex (MAC). C5a, the most potent chemotactic anaphylatoxin, may attract neutrophils to the site of inflammation, leading to superoxide production, while MAC is deposited over endothelial cells and smooth vessel cells, leading to cell injury. Experimental evidence suggests that tissue salvage may be achieved by inhibition of the complement pathway. As the complement is composed of a cascade of proteins, it provides numerous sites for pharmacological interventions during acute myocardial infarction. Although various strategies aimed at modulating the complement system have been tested, the ideal approach probably consists of maintaining the activity of C3 (a central protein of the complement cascade) and inhibiting the later events implicated in ischemia/reperfusion and also in targeting inhibition in a tissue-specific manner. [source] Complement Activation in Emergency Department Patients With Severe SepsisACADEMIC EMERGENCY MEDICINE, Issue 4 2010John G. Younger Abstract Objectives:, This study assessed the extent and mechanism of complement activation in community-acquired sepsis at presentation to the emergency department (ED) and following 24 hours of quantitative resuscitation. Methods:, A prospective pilot study of patients with severe sepsis and healthy controls was conducted among individuals presenting to a tertiary care ED. Resuscitation, including antibiotics and therapies to normalize central venous and mean arterial pressure (MAP) and central venous oxygenation, was performed on all patients. Serum levels of Factor Bb (alternative pathway), C4d (classical and mannose-binding lectin [MBL] pathway), C3, C3a, and C5a were determined at presentation and 24 hours later among patients. Results:, Twenty patients and 10 healthy volunteer controls were enrolled. Compared to volunteers, all proteins measured were abnormally higher among septic patients (C4d 3.5-fold; Factor Bb 6.1-fold; C3 0.8-fold; C3a 11.6-fold; C5a 1.8-fold). Elevations in C5a were most strongly correlated with alternative pathway activation. Surprisingly, a slight but significant inverse relationship between illness severity (by sequential organ failure assessment [SOFA] score) and C5a levels at presentation was noted. Twenty-four hours of structured resuscitation did not, on average, affect any of the mediators studied. Conclusions:, Patients with community-acquired sepsis have extensive complement activation, particularly of the alternative pathway, at the time of presentation that was not significantly reversed by 24 hours of aggressive resuscitation. ACADEMIC EMERGENCY MEDICINE,2010; 17:353,359 © 2010 by the Society for Academic Emergency Medicine [source] Speleothem preservation and diagenesis in South African hominin sites implications for paleoenvironments and geochronologyGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 5 2009Philip J. Hopley Plio-Pleistocene speleothems from australopithecine-bearing caves of South Africa have the potential to yield paleoenvironmental and geochronological information using isotope geochemistry. Prior to such studies it is important to assess the preservation of geochemical signals within the calcitic and aragonitic speleothems, given the tendency of aragonitic speleothems to recrystallize to calcite. This study documents the geochemical suitability of speleothems from the principal hominin-bearing deposits of South Africa. We use petrography, together with stable isotope and trace element analysis, to identify the occurrence of primary aragonite, primary calcite, and secondary calcite. This study highlights the presence of diagenetic alteration at many of the sites, often observed as interbedded primary and secondary fabrics. Trace element and stable isotopic values distinguish primary calcite from secondary calcite and offer insights into geochemical aspects of the past cave environment. ,13C values of the primary and secondary calcites range from +6 to ,9, and ,18O values range from ,4 to ,6,. The data are thus typical of meteoric calcites with highly variable ,13C and relatively invariant ,18O. High carbon isotope values in these deposits are associated with the effects of recrystallization and rapid outgassing of CO2 during precipitation. Mg/Ca and Sr/Ca ratios differ between primary and secondary calcite speleothems, aiding their identification. Carbon and oxygen isotope values in primary calcite reflect the proportion of C3 and C4 vegetation in the local environment and the oxygen isotope composition of rainfall. Primary calcite speleothems preserve the pristine geochemical signals vital for ongoing paleoenvironmental and geochronological research. © 2009 Wiley Periodicals, Inc. [source] Palaeomagnetism, rock magnetism and geochemistry of Jurassic dykes and correlative redbeds, Massachusetts, USAGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2000Suzanne A. McEnroe Jurassic diabase dykes, sills and sedimentary rocks in central Massachusetts were sampled for palaeomagnetic analysis. The intrusions fall into three of the chemical types for eastern North American diabases: high TiO2 quartz-normative (Holden); low TiO2 quartz-normative (Ware); and high Fe2O3 quartz-normative (Pelham,Loudville). The characteristic magnetizations in the majority of intrusive samples unblock between 550 °C and 580 °C, with Curie temperatures in a discrete interval between 556 °C and 580 °C. The dominant remanence in the diabases is carried by C1 to C3 oxidation-exsolved titanomagnetite occurring as euhedral grains, as fine needles or dust in the matrix, as devitrifed glass, and as fine magnetite-ilmenite-silicate symplectite. In some dykes, titanomagnetite was further modified by deuteric oxidation during post-magmatic cooling, creating titanomaghematite and/or a granulation of the magnetite. Palaeopoles for the three diabase groups are: Holden, 60.1°N, 80.5°E, A95 = 4.1°; Ware, 73.5°N, 85.8°E, A95 = 3.9°; and Pelham,Loudville, 65.3°N, 95.6°E, A95 = 4.1°. These data are combined with samples from two stratigraphic sections through the Early Jurassic part of the Sugarloaf Formation in the Deerfield Basin representing both fine-grained mudstones and coarser arkoses. These haematite-dominated rocks reveal several components of magnetization, a steep recent field direction, an intermediate secondary diagenetic overprint direction in both mudstones and arkoses, and a high-temperature shallow primary direction found only in the mudstones. Palaeopoles for the Sugarloaf Formation are: mudstones, 57.7°N, 81.3°E, A95 = 9.1°; and arkoses, 75.1°N, 131.6°E, A95 = 5.9°. Based on the new palaeomagnetic data reported here, the North American plate in the Middle Jurassic was at higher palaeolatitudes than indicated by the present North American apparent polar wander path. [source] | ||||||||||||||||||||||||||||||||||||||||