bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modelling the Electron‐Transfer Complex Between Aldehyde Oxidoreductase and Flavodoxin
Authors: Krippahl Ludwig , Palma P. Nuno , Moura Isabel , Moura José J. G. 
Published: August 2006

AbstractThree‐dimensional protein structures of the xanthine oxidase family show different solutions for the problem of transferring electrons between the flavin adenine dinucleotide (FAD) group and the molybdenum cofactor. In xanthine oxidase all the cofactors lie within domains of the same protein chain, whereas in CO dehydrogenase the Fe–S centres, FAD and Mo cofactors are enclosed in separate chains and the enzyme exists as a stable complex of all three. In aldehyde oxidoreductase, only Fe–S and Mo co‐factors are present in a single protein chain. Flavodoxin is docked to aldehyde oxidoreductase to mimic the flavin component on the intramolecular electron transfer chain of aanthine oxidase and CO dehydrogenase and, remarkably, the main features of the electron‐transfer pathway are observed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Chiral Molecules Containing Metal–Metal Bonds
Authors: Cotton F. Albert , Murillo Carlos A. 
Published: August 2006

AbstractMany chiral compounds having metal–metal bonds are now known in which the M–M unit is the chromophore. In this review they are classified as those where it is either (1) an inherently chiral chromophore owing to helical stacking of metal–ligand bonds, or (2) not inherently chiral but surrounded by a collection of ligands bearing chiral substituents. In only a few cases have the actual CD and/or ORD spectra been measured and analyzed. These include M2X4(PP)2 molecules (PP = a bridging diphosphane) and M2(O2CR)4 molcules where R is chiral. The more recently discovered helical extended metal atom chain (EMAC) molecules are also mentioned. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Blue green algae in the biological soil crusts of different regions of India
Authors: Tirkey J. , Adhikary S. P. 
Published: August 2006

AbstractBlue green algae (Cyanobacteria) occurring as biological soil crust intermingled with soil particles in the upper few millimeters of soil surfaces from different regions of India were studied. Sampling of crusts was done from four different soil types, i.e. laterite soils of the east coast, brown forest of soils of the east and central region, arid soils of the southern region and sandy soils of the west coast of India. One species each of the blue green algae Lyngbya arboricola, Scytonema ocellatum, Scytonema chiastum and Plectonema notatum as the dominant component in the four types of crust. Seve‐ ral other species of blue green algae belonging to genera Oscillatoria, Phormidium, Microcoleus, Nostoc, Aulosira, Calothrix, Hapalosiphon, Fischerella, Westiellopsis and Stigonema also appeared in the enrichment culture as minor components along with the dominant species. No other species of any other group of algae was a component of these crusts during the dry season. A total number of 48 species attributed to 15 different genera was encountered in different biological soil crusts of India. All these species are described with illustrations. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Contributions to the pollen morphology of the tribe Inuleae (subfamily Asteroideae‐Compositae) in the flora of Egypt
Authors: Osman A. K. 
Published: August 2006

AbstractThe pollen morphology of 18 species of tribe Inuleae belonging to 10 genera was examined by light and scanning microscopy. Pollen grains usually trizonocolpate to trizonocolporate rarely 4‐zonocolporate. Shape commonly oblate‐spheroidal to spheroidal, with some suboblate types. Tectum echinate to echinulate. Tectum in‐between the spines or spinules is sub‐psilate, perforate to scabrate or microreticulate. On the basis of the pollen class and the exine pattern, three distinct pollen types are recognized viz., Pollen type‐I: Anvillea garcinii, Pollen type‐II: Nauplius graveolens and Pollen type‐III: Pulicaria . Within the pollen types, pollen characters are significantly sufficient for characterization of the species. An interesting correlation observed is that the taxa having slightly thick exine (4–7 µm) with echinate or echinulate tectum. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Morphological, reproductive and mycobiota characters of three wild medicinal plants inhabiting Western Mediterranean coastal Land, Egypt
Authors: Abdel‐Hafez S. I. I. , El Naggar S. M. 
Published: August 2006

AbstractLeaf surface, pollen morphology and mycobiota as well as leaf spots have been investigated in three wild medicinal plant species [Fagonia cretica L.(Zygophyllaceae);Peganum harmalaL. (Peganaceae) andScorzonera undulataVahl (Asteraceae)] growing in Egypt. Thirty eight fungal species belonging to 18 genera were collected from leaf surfaces (15 genera and 32 species) and anthers/pollen grains (16/26) ofF. cretica,P. harmalaandS. undulataon Czapek‐Dox agar at 27 °C. There is basic similarity of mycobiota in the two microhabitats (leaf surface and anther/pollen grains) of the three wild medicinal plants with the most frequently encountered fungi wereAlternaria alternata, Cladosporium herbarum,andUlocladium botrytis.Also some members ofAspergillus, FusariumandStemphyliumwere only common in any of the two microhabitats. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Testa sculptures in Allium L. subg. Melanocrommyum (WEBB & BERTH.) Rouy (Alliaceae)
Authors: Fritsch R. M. , Kruse J. , Adler K. , Rutten T. 
Published: August 2006

AbstractThe sculptures and shape of the outer walls of seed epidermal cells were studied in a broad material from different sources. Convex periclinal walls with several to many large prominent sculptures (verrucae) occurred most often but generally the sculpturing was rather diverse. Most variable were the anticlinal walls. Mostly they were undulated with different amplitudes and wavelengths and belonged to three types (S‐like, U‐like, and Omega‐like undulation). Also transitions between these types occurred. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Impact of redox and transport processes in a riparian wetland on stream water quality in the Fichtelgebirge region, southern Germany
Authors: Lischeid G. , Kolb A. , Alewell C. , Paul S. 
Published: August 2006

AbstractBiologically mediated redox processes in the riparian zone, like denitrification, can have substantially beneficial impacts on stream water quality. The extent of these effects, however, depends greatly on the hydrological boundary conditions. The impact of hydrological processes on a wetland's nitrogen sink capacity was investigated in a forested riparian fen which is drained by a first‐order perennial stream. Here, we analysed the frequency distributions and time‐series of pH and nitrogen, silica, organic carbon and oxygen concentrations in throughfall, soil solution, groundwater and stream water, and the groundwater levels and stream discharges from a 3‐year period. During baseflow conditions, the stream was fed by discharging shallow, anoxic groundwater and by deep, oxic groundwater. Whereas the latter delivered considerable amounts of nitrogen (∼0·37 mg l−1) to the stream, the former was almost entirely depleted of nitrogen. During stormflow, near‐surface runoff in the upper 30 cm soil layer bypassed the denitrifying zone and added significant amounts to the nitrogen load of the stream. Nitrate‐nitrogen was close to 100% of deep groundwater and stream‐water nitrogen concentration. Stream‐water baseflow concentrations of nitrate, dissolved carbon and silica were about 1·6 mg l−1, 4 mg l−1 and 7·5 mg l−1 respectively, and >3 mg l−1, >10 mg l−1 and <4 mg l−1 respectively during discharge peaks. In addition to that macroscale bypassing effect, there was evidence for a corresponding microscale effect: Shallow groundwater sampled by soil suction cups indicated complete denitrification and lacked any seasonal signal of solute concentration, which was in contrast to piezometer samples from the same depth. Moreover, mean solute concentration in the piezometer samples resembled more that of suction‐cup samples from shallower depth than that of the same depth. We conclude that the soil solution cups sampled to a large extent the immobile soil‐water fraction. In contrast, the mobile fraction that was sampled by the piezometers exhibited substantially shorter residence time, thus being less exposed to denitrification, but predominating discharge of that layer to the stream. Consequently, assessing the nitrogen budget based on suction‐cup data tended to overestimate the nitrogen consumption in the riparian wetland. These effects are likely to become more important with the increased frequency and intensity of rainstorms that are expected due to climate change. Copyright © 2006 John Wiley & Sons, Ltd.
Hydrodynamics and geomorphic work of jökulhlaups (glacial outburst floods) from Kverkfjöll volcano, Iceland
Authors: Carrivick Jonathan L. 
Published: August 2006

AbstractJökulhlaups (glacial outburst floods) occur frequently within most glaciated regions of the world and cause rapid landscape change, infrastructure damage, and human disturbance. The largest jökulhlaups known to have occurred during the Holocene within Iceland drained from the northern margin of Vatnajökull and along the Jökulsá á Fjöllum. Some of these jökulhlaups originated from Kverkfjöll volcano and were routed through anastomosing, high gradient and hydraulically rough channels. Landforms and sediments preserved within these channels permit palaeoflow reconstructions.Kverkfjöll jökulhlaups were reconstructed using palaeocompetence (point measurements), slope–area (one‐dimensional), and depth‐averaged two‐dimensional (2D) hydrodynamic modelling techniques. The increasing complexity of 2D modelling required a range of assumptions, but produced information on both spatial and temporal variations in jökulhlaup characteristics. The jökulhlaups were volcanically triggered, had a linear‐rise hydrograph and a peak discharge of 50 000–100 000 m3s−1, which attenuated by 50–75% within 25 km. Frontal flow velocities were ∼2 m s−1; but, as stage increased, velocities reached 5–15m s−1. Peak instantaneous shear stress and stream power reached 1 × 104N m−2and 1 × 105W m−2respectively.Hydraulic parameters can be related to landform groups. A hierarchy of landforms is proposed, ranging from the highest energy zones (erosional gorges, scoured bedrock, cataracts, and spillways) to the lowest energy zones (of valley fills, bars, and slackwater deposits). Fluvial erosion of bedrock occurred in Kverkfjallarani above ∼3 m flow depth, ∼7m s−1flow velocity, ∼1 × 102N m−2shear stress, and 3 × 102W m−2stream power. Fluvial deposition occurred in Kverkfjallarani below ∼8 m flow depth, 11 m s−1flow velocity, 5 × 102N m−2shear stress, and 3 × 103W m−2stream power. Hence, erosional and depositional ‘envelopes’ have considerable overlap, probably due to transitional flow phenomena and the influence of upstream effects, such as hydraulic ponding and topographic constrictions, for example.Holocene Kverkfjöll jökulhlaups achieved geomorphic work comparable to that of other late Pleistocene ‘megafloods’. This work was a result of steep channel gradients, topographic channel constrictions, and high hydraulic roughness, rather than to extreme peak discharges. The Kverkfjöll jökulhlaups have implications for landscape evolution in north‐central Iceland, for water‐sediment inputs into the North Atlantic, and for recognizing jökulhlaups in the rock record. 2D hydrodynamic modelling is likely to be important for hazard mitigation in similar landscapes and upon other glaciated volcanoes, because it only requires an input hydrograph and a digital elevation model to run a model, rather than suites of geomorphological evidence and field‐surveyed valley cross‐sections, for example. Copyright © 2006 John Wiley & Sons, Ltd.
Ocular phenotype in a mouse gene knockout model for infantile neuronal ceroid lipofuscinosis
Authors: Lei Bo , Tullis Gregory E. , Kirk Mark D. , Zhang Keqing , Katz Martin L. 
Published: August 2006

AbstractMutations in the human protein palmitoyl thioesterase‐1 (PPT‐1) gene result in an autosomal recessive neurodegenerative disorder designated neuronal ceroid lipofuscinosis (NCL), type CLN1, or infantile NCL. Among the symptoms of the CLN1 disease are accumulation of autofluorescent lysosomal storage bodies in neurons and other cell types, seizures, motor and cognitive decline, blindness, and premature death. Development of an effective therapy for this disorder will be greatly assisted by the availability of suitable animal models. A mouse PPT‐1 gene knockout model has recently been generated. Studies were performed to determine whether the mouse model exhibits ocular features of the human CLN1 disorder. A progressive accumulation of autofluorescent storage material in all layers of the retina was observed in the PPT‐1 knockout mice. Accompanying the storage body accumulation was a modest loss of cells with nuclei in the outer and inner nuclear layers. As indicated by electroretinogram (ERG) responses, retinal function was only mildly impaired at 4 months of age but was severely impaired by 8 months, despite only modest changes in retinal morphology. The pupillary light reflex (PLR), on the other hand, was exaggerated in the knockout mice. The apparent anomaly between the ERG and the PLR findings suggests that disease‐related PLR changes may be due to changes in extraocular signal processing. The pronounced ocular phenotype in the PPT‐1 knockout mice makes these animals a good model for testing therapeutic interventions for treatment of the human CLN1 disorder. © 2006 Wiley‐Liss, Inc.
Plant and fruit characteristics of cactus pear (Opuntia spp.) cultivars in South Africa
Authors: Oelofse Rachel M , Labuschagne Maryke T , Potgieter Johan P 
Published: August 2006

AbstractThe cultivation of cactus pear requires low input and is therefore conducive to a sustainable system that will increase the efficiency and economic viability of the small and medium‐sized farms of low‐income farmers. The aim of this study was to determine fruit and plant characteristics of the 10 most commonly grown cactus pear cultivars in South Africa under rain‐fed, subtropical conditions. Skinners Court favoured vegetative growth. The fruit of Gymno Carpo had below average total soluble sugars. Roedtan had high cladode yield, while producing fruit of good quality, especially high total soluble sugar values, and quantity. Turpin and Meyers proved to have the highest fruit yield, fruit mass, cladode yield and number of cladodes pruned per plant. These cultivars can therefore be planted for both fruit production and for harvesting of cladodes for animal feed. Copyright © 2006 Society of Chemical Industry
Source and changes of proteinase activities of Indian anchovy (Stolephorus spp.) during fish sauce fermentation
Authors: Siringan Patcharin , Raksakulthai Nongnuch , Yongsawatdigul Jirawat 
Published: August 2006

AbstractTrypsin‐like proteinases exhibited the highest activity in viscera and muscle of Indian anchovy (Stolephorus spp.). The molecular weights (MWs) of proteinases in viscera were estimated to be 31, 35, 44, 49 and 57 kDa by activity staining in the presence of 4 mol L−1 NaCl. The MW of proteinase extracted from muscle was 56 kDa. This reflects that only one proteinase was extracted from muscle whereas five proteinases were extracted from viscera. Trypsin‐like, chymotrypsin‐like and cathepsin L‐like proteinases were found in commercial fish sauce samples throughout 12 months of fermentation, suggesting that these proteinases were stable at high salt concentrations (250–300 g kg−1 NaCl) and under acidic conditions (pH 5.2–5.8). In contrast, leucine aminopeptidase activity was detected only in the first month. The MWs of proteinases found in fish sauce after various fermentation periods were estimated to be 37, 47 and 53 kDa, which coincided with the MWs of proteinases found in Indian anchovy. Copyright © 2006 Society of Chemical Industry
A fast method for determining low‐molecular‐mass aliphatic carboxylic acids by high‐performance liquid chromatography–atmospheric pressure chemical ionization mass spectrometry
Authors: Käkölä Jaana , Alén Raimo 
Published: August 2006

AbstractA fast quantitative high‐performance liquid chromatographic separation method with atmospheric pressure chemical ionization mass spectrometric detection (HPLC‐APCI‐MS) was developed for the determination of low‐molecular‐mass aliphatic mono‐ and dicarboxylic acids typically present in different industrial process waters. A mixture of glycolic, lactic, α‐glucoisosaccharinic, oxalic, maleic, fumaric, succinic, malic, glutaric, methylsuccinic, and adipic acids was separated using an RP chromatographic system. Adipic acid was used as an internal standard to calculate correlation coefficients for the acids studied. The chromatographic analysis of these acids was primarily carried out by means of gradient elution with an aqueous formic acid solution (0.15%, pH 2.5) and methanol using a modified C18 stationary phase. Good acid separation could be obtained for all acids by optimizing the chromatographic conditions. The method provides a simple sample preparation and faster analysis time compared to the traditional gas chromatographic methods, thus enabling almost real‐time monitoring of these acids. Finally, the method developed was applied to the analysis of a complex mixture of aliphatic hydroxy carboxylic acids, which are formed as alkaline degradation products of carbohydrates during wood delignification and are present in the cooking spent liquor (black liquor).
Engineered Bio‐Active Polysaccharides from Heparin
Authors: Guimond Scott E. , Turnbull Jeremy E. , Yates Edwin A. 
Published: August 2006

AbstractSummary: Heparin, the well‐known anticoagulant polysaccharide, is also active in many other biological systems owing to its structural similarity to HS, but usually lacks selectivity because it is more highly sulfated. A series of straightforward chemical reactions (de‐O‐sulfation, de‐N‐sulfation and re‐N‐acetylation), carried out to partial or complete extent, were combined, resulting in a number of modified heparin polysaccharide derivatives with altered properties. These exhibited a range of abilities to promote cell signalling through the FGF/FGFR tyrosine kinase signalling system, in an in vitro cell assay with combinations of FGF‐1, ‐2, ‐3 and FGFR 1 and 3. One polysaccharide (N‐acetylated, 6‐O‐ and 2‐O‐sulfated heparin), with only a fraction (<10−3) of the anticoagulant activity of heparin (200 U · mg−1), promoted FGF‐2‐mediated angiogenesis (10‐fold) and therefore had an improved ratio of pro‐angiogenic activity to anticoagulant activity in excess of 104 compared to heparin. These results demonstrate that heparin‐derived polysaccharides can be engineered for selected activities and have potential in a wide range of medical, biotechnological and tissue‐engineering applications.Effect of selected engineered heparin polysaccharides on angiogenesis.magnified imageEffect of selected engineered heparin polysaccharides on angiogenesis.
Development of a Model Bladder Extracellular Matrix Combining Disulfide Cross‐Linked Hyaluronan with Decellularized Bladder Tissue
Authors: Brown Allison L. , Srokowski Elizabeth M. , Shu Xiao Z. , Prestwich Glenn D. , Woodhouse Kimberly A. 
Published: August 2006

AbstractSummary: In this work we investigate the feasibility of modifying porcine‐derived BAM to include HA with a view to developing a model, artificial extracellular matrix for the study of bladder cell‐matrix interactions. HA‐DPTH was incorporated into BAM disks and then cross‐linked oxidatively to a disulfide containing hydrogel. Disks were seeded with bladder smooth muscle cells (BSMC) and UEC under three culture configurations and incubated for 3, 7, and 14 d. At each time point, matrix contraction was measured, and media supernatants assayed for cell‐secreted gelatinase activity. To evaluate cell adherence and organization, triple immunofluorescent labeling of cell nuclei, actin cytoskeleton, and focal contacts was performed. HA‐modified BAM exhibited a significant increase in matrix contraction and induced a higher level of cell‐secreted gelatinase activity compared to unmodified BAM. Immunofluorescent labeling demonstrated that BSMCs remained adherent to both scaffold types over time. The distribution and organization of the cytoskeleton and focal contacts did not appear to be altered by the presence of HA. Interestingly, cellular infiltration into modified BAM was evident by 7 d and continued beyond 14 d, while BSMCs seeded onto unmodified BAM remained localized to the surface out to 14 d, with minimal infiltration evident only at day 28. These differences in cell infiltration support the gelatinase activity results. Increases in cell migration and matrix proteolysis in the presence of HA may be contributing factors toward BAM remodeling leading to increased matrix contraction with time. The model ECM developed in this work will be utilized for future studies aimed at elucidating the mechanisms controlling key remodeling events associated with bladder repair.Matrix contraction of cell‐seeded BAM scaffolds.magnified imageMatrix contraction of cell‐seeded BAM scaffolds.
Water, Solute, and Segmental Dynamics in Polysaccharide Hydrogels
Authors: Cavalieri Francesca , Chiessi Ester , Finelli Ivana , Natali Francesca , Paradossi Gaio , Telling Mark F. 
Published: August 2006

AbstractSummary: Polysaccharide hydrogels have found several applications in the food industry, in biomedicine, and cosmetics. The study of polysaccharide hydrogels offers a challenging scenario of intrinsic heterogeneities in the crosslinking density and large time and space ranges that characterize a number of dynamic processes entailing segmental motions, water diffusion, and small‐molecule diffusion. The understanding of such complex features is essential because of the extensive use of polysaccharidic moieties in the food industry, biomedical devices, and cosmetics. The study of phenomena occurring at the nanoscale to the mesoscale requires the combination of investigative tools to probe different time and distance scales and the structural characterization of the networks by established methodologies such as swelling and elastic modulus measurements. Elastic and quasielastic neutron scattering, and fluorescence recovery after photobleaching are emerging methodologies in this field. In this feature article we focus, somewhat arbitrarily, on these new approaches because other techniques, such as low‐resolution proton NMR relaxometry and rheology, have been already described thoroughly in the literature. Case examples of polysaccharide hydrogels studied by neutron scattering and fluorescence recovery are presented here as contributions to the comprehension of the dynamic behavior of physical and chemical hydrogels based on polysaccharides.Quasielastic incoherent neutron scattering experiment on a Sephadex hydrogel sample at different temperatures.magnified imageQuasielastic incoherent neutron scattering experiment on a Sephadex hydrogel sample at different temperatures.
A Reactive Flame Retardant as a Poly(propylene)‐Sized Glass Adhesion Promoter
Authors: Dvir Haim , Gottlieb Moshe 
Published: August 2006

AbstractSummary: Contact‐mode AFM adhesion strength measurements were employed in order to investigate the capability of PBBMA FR as an adhesion promoter in PP composites. The reactive FR exhibited superior coupling properties in comparison to conventional coupling agents such as PP‐g‐ma introduced in reinforced PP composites.AFM image showing the recess carved out by the AFM tip in a PBBMA layer deposited on glass treated with APS.magnified imageAFM image showing the recess carved out by the AFM tip in a PBBMA layer deposited on glass treated with APS.