bluuebunny/crossref_metadata_2025_split huggingface dataset:
Importance of N‐linked glycosylation in the functional expression of murine CD1d1
Authors: Sriram Venkataraman , Willard Claire A. , Liu Jianyun , Brutkiewicz Randy R. 
Published: August 2007

SummaryThe mouse CD1d1 glycoprotein is specialized in presenting lipid antigens to a novel class of T cells called natural killer T (NKT) cells. CD1d1 is predicted to contain five potential N‐linked glycosylation sites (asparagine residues at positions 25, 38, 60, 128, and 183). Glycosylation has been shown to invariably affect the molecular and functional properties of various glycoproteins, and in the current report it was found that a conservative change of the individual endogenous asparagine residues in CD1d1 to glutamine differentially affected its functional expression. Although the maturation rate of the glycosylation mutants was comparable to that of wild type, they differed in their relative levels of surface expression and in their ability to stimulate NKT cells. Mutating all five glycosylation residues resulted in the absence of detectable CD1d1 expression, with a concomitant lack of NKT cell activation. Therefore, these results demonstrate that glycosylation plays a significant role in the functional expression of CD1d1.
Low‐temperature bitumen stiffness and viscous paraffinic nano‐ and micro‐domains by cryogenic AFM and PDM
Authors: MASSON J‐F. , LEBLOND V. , MARGESON J. , BUNDALO‐PERC S. 
Published: August 2007

SummaryIn an effort to better understand the structure and behaviour of bitumen in low temperature, we describe the first use of cryogenic atomic force microscopy and phase detection microscopy to characterize bitumen nano‐ and micro‐structures. The results were interpreted in light of glass transition temperatures (Tgs) for bitumen fractions. The domains visible by microscopy, the catana, peri and para phases, were attributed to domains rich in asphaltenes, naphthene and polar aromatics, and saturates, respectively. Between −10°C and −30°C, atomic force microscopy images revealed topographic features not visible in atomic force microscopy images acquired at room temperature. According to phase detection microscopy and Tgs, the features were assigned to viscous unfrozen saturates. Upon cooling to −72°C, unfrozen domains of 20–400 nm were observed. These domains were found in the paraphase rich in saturates and in the periphase rich in naphthene aromatics and polar aromatics. The findings indicate that new viscous domains form upon cooling to low temperatures owing to phase segregation, and that some bitumens are never entirely rigid in low temperatures.
The use of amphipathic polymers for cryo electron microscopy of NADH:ubiquinone oxidoreductase (complex I)
Authors: FLÖTENMEYER MATTHIAS , WEISS HANNS , TRIBET CHRISTOPHE , POPOT JEAN‐LUC , LEONARD KEVIN 
Published: August 2007

SummaryIn the three‐dimensional (3D) structure determination of macromolecules, cryo electron microscopy (cryo‐EM) is an important method for obtaining micrographs of unstained specimens for the single‐particle reconstruction approach. For cryo‐EM, proteins are fixed in a frozen hydrated state by quick‐freezing in a thin water layer on a holey carbon film. Cryo‐EM of detergent‐solubilized membrane proteins is hindered by the fact that detergents reduce the surface tension of water, so that it is difficult to control the ice thickness and the distribution of protein. Amphipols are a new class of amphipathic polymers designed to handle membrane proteins in aqueous solutions under particularly mild conditions. Amphipol A8‐35 stabilizes NADH:ubiquinone oxidoreductase (complex I) from Neurospora crassa and keeps it water‐soluble in the absence of free detergent. Electron microscope images of quick‐frozen complex I/A8‐35 samples were used for computer‐based single‐particle averaging and 3D reconstruction, and the reconstruction of unstained frozen‐hydrated particles compared with previous detergent‐based reconstructions. The potential of amphipols for cryo‐EM is discussed.
Recrystallization behaviour of the nickel‐based alloy 80 A during hot forming
Authors: MITSCHE S. , POELT P. , SOMMITSCH C. 
Published: August 2007

SummaryThe dynamic recrystallization as well as meta‐dynamic and static recrystallization of the nickel‐based alloy 80A was investigated by means of electron backscatter diffraction (EBSD). Specimens were hot compressed at a temperature of 1120°C and a strain rate of 0.1/s at varying strain and soak times to describe the recrystallization behaviour. Various approaches were tested in order to differentiate between recrystallized and deformed grains based on EBSD data. The grain orientation spread was clearly found to be the most reliable procedure. A high twinning of the recrystallized grains was observed, and as a consequence the measured grain size was strongly dependent on whether the coherent and incoherent twin boundaries were regarded as genuine boundaries or removed.
The interpretation of indexing of high Σ CSL grain boundaries from ceramics
Authors: SHIH SHAO‐JU , PARK MYUNG‐BEOM , COCKAYNE DAVID J. H. 
Published: August 2007

SummaryElectron backscatter diffraction (EBSD) is a useful technique for measuring the orientation of individual grains and for determining grain boundary misorientations in polycrystals. However, its application to ceramics is more difficult than to metals, because the surface quality that can be achieved often makes the Kikuchi patterns blurred. As a consequence, it can be difficult, even for automated systems, to differentiate between different grain orientations, which have similar patterns. In this paper, we carry out EBSD analyses of SrTiO3 polycrystalline material prepared with different polishing methods, and we consider the effect of different criteria in interpreting the EBSD patterns from them. In particular, we investigate the CSL statistics using both the Palumbo and Aust and the Brandon criteria in this situation.
LEUCOCYTE ADHESION MOLECULES IN ISCHAEMIC RENAL INJURY: KIDNEY SPECIFIC PARADIGMS?
Authors: Rabb Hamid , Postler Gilbert 
Published: August 2007

1. Renal ischaemic–reperfusion injury (IRI) is an important cause of acute renal failure in native kidneys and in allografts.2. Leucocyte adhesion molecules CD11/CD18, intercellular adhesion molecule‐1 and selectins mediate cardiac, skin and muscle IRI in experimental models and recent studies have begun to evaluate their role in renal IRI.3. The CD11/CD18 has been shown to mediate renal IRI in rat models.4. Intercellular adhesion molecule‐1 has a more prominent role in mediating renal IRI than CD11/CD18 in both rat and mouse models. Blockade of both pathways together appears to provide synergistic protection.5. Unlike in heart and muscle, L‐selectin does not appear to mediate leucocyte recruitment to postischaemic kidney or tubular damage.6. Leucocyte adhesion molecules may mediate renal IRI by mechanisms other than simply leucocyte migration, such as signal transduction and cell transport.Presented at the Experimental Biology Symposium on the Role of Integrins in Acute Renal Failure, New Orleans, Louisiana, USA, 1997.
DIFFERENT MECHANISMS FOR [Ca2+]i OSCILLATIONS INDUCED BY CARBACHOL AND HIGH CONCENTRATIONS OF [Ca2+]o IN THE RAT VENTRICULAR MYOCYTE
Authors: Wang Hong‐Xin , Ouyang Ming , Zhang Wei‐Min , Sheng Jian‐Zhong , Wong Tak‐Ming 
Published: August 2007

1. The purpose of the present study was to explore the different mechanisms of [Ca2+]i oscillations induced by high concentrations of either carbachol (CCh) or extracellular Ca2+ ([Ca2+]o). First, we compared the oscillations induced by CCh at concentrations of 100–300 μmol/L and [Ca2+]o (5 mmol/L) in the single rat ventricular myocyte. Second, we studied CCh‐ and [Ca2+]o‐induced [Ca2+]i oscillations following either interference with the production of inositol trisphosphate (IP3), reductions in cytosolic Ca2+ ([Ca2+]i), inhibition of Ca2+ influx and Na+–Ca2+ exchange or depletion of Ca2+ from its intracellular store.2. The [Ca2+]i oscillations induced by CCh were frequent and were superimposed on [Ca2+]i transients in electrically stimulated cells, whereas those induced by high [Ca2+]o were occasional and occurred in quiescent cells and between [Ca2+]i transients in electrically stimulated cells. In both cases, [Ca2+]i oscillations were preceded by an increase in resting levels of [Ca2+]i.3. Carbachol‐induced [Ca2+]i oscillations were accompanied by an increase in amplitude and prolongation of the time of decline to 80% of the peak of the [Ca2+]i transient, while high [Ca2+]o‐induced [Ca2+]i oscillations were the opposite.4. A reduction of [Ca2+]o to 0.1 mmol/L and treatment with Ni2+ or ryanodine or 1,2‐bis(2‐aminophenoxy)ethane‐N,N,N',N'‐tetraacetic acid AM (BAPTA‐AM) abolished the [Ca2+]i oscillations induced by both CCh and high [Ca2+]o.5. The calcium channel blockers verapamil and nifedipine and inhibitors of phospholipase C (neomycin and U‐73122) abolished the [Ca2+]i oscillations induced by CCh; Li+ accelerated the onset of the [Ca2+]i oscillations induced by CCh.6. These observations suggest that the mechanisms responsible for the [Ca2+]i oscillations induced by CCh and high [Ca2+]o are different from each other. Other than an increase in extracellular Ca2+ influx as a mechanism common for both CCh‐ and high [Ca2+]o‐induced [Ca2+]i oscillations, the CCh‐induced [Ca2+]i oscillations involve influx of Ca2+ via L‐type Ca2+ channels, Na+–Ca2+ exchange, mobilization of intracellular Ca2+ and IP3 production.
GLUCURONIDATION OF DIHYDROCODEINE BY HUMAN LIVER MICROSOMES AND THE EFFECT OF INHIBITORS
Authors: Kirkwood Lynette C , Nation Roger L , Somogyi* Andrew A 
Published: August 2007

1. Glucuronidation is the major route of metabolism of dihydrocodeine (DHC) and accounts for 25–30% of an oral dose in urine. The kinetics of DHC‐6‐glucuronide formation in liver microsomes from five human donors and the effect of a number of potential inhibitor drugs were examined using a newly developed and validated HPLC assay.2. The formation of DHC‐6‐glucuronide exhibited atypical kinetics that conformed to the Hill equation. The mean intrinsic dissociation constant (Ks) and maximum velocity (Vmax) values were 1566 μmol/L and 0.043 μmol/min per g, respectively. The Ks and Vmax values varied 1.5‐ and 3.5‐fold, respectively.3. Seven drugs were tested for inhibitory effects on DHC glucuronidation at low (50 μmol/L) and high (500 μmol/L) concentrations. At 50 μmol/L, only diclofenac produced greater than 50% inhibition, while at concentrations of 500 μmol/L inhibition was greater than 35% for diclofenac, amitriptyline, oxazepam, naproxen, chloramphenicol and probenecid, but not paracetamol.4. The present study found little interindividual variation in the activity of human liver microsomes for glucuronidation of DHC. Comparison of the results from the inhibition studies with those reported previously for codeine and morphine suggest that the UDP‐glucuronosyltransferase isoform UGT2B7 is involved in the glucuronidation of DHC.
THERAPEUTIC EFFECT OF ARGININE–GLYCINE–ASPARTIC ACID PEPTIDES IN ACUTE RENAL INJURY
Authors: Goligorsky Michael S , Noiri Eisei , Kessler Horst , Romanov Victor 
Published: August 2007

1. Previous studies from our laboratory have suggested that arginine–glycine–aspartic acid (RGD) peptides, serving as a decoy, may prevent tubular obstruction in the ischaemic model of acute renal failure. Specifically, we have demonstrated that: (i) stressed tubular epithelial cells reverse the polarity of integrin receptors from the predominantly basolateral location to the apical cell membrane as a part of a more generalized process of the loss of epithelial cell polarity; (ii) depletion of integrins expressed on the basal cell surface leads to the loss of anchorage to the basement membrane and cell desquamation; (iii) expression of integrin receptors on the apical cell membrane leads to indiscriminate interactions (e.g. the adhesion of desquamated cells to the cells remaining in situ), thus initiating the process of tubular obstruction; and (iv) conglomeration of the desquamated cells via integrin receptors further aggravates tubular obstruction.2. Importantly, these integrin‐based interactions can be blocked by synthetic RGD peptides. The linear RGD peptide injected into the renal artery upon release of the renal artery clamp prevented the elevation of proximal tubular hydrostatic pressure characteristically seen in animals with renal ischaemia that received injection of the vehicle of an inactive peptide.3. In vivo study of RGD peptides in ischaemic acute renal failure in rats demonstrated attenuation of renal injury and accelerated recovery of renal function.4. Using linear RGD peptide labelled with 99mTc, we have shown that this probe was retained in ischaemic kidneys.5. To visualize RGD binding sites at the cellular level, we performed a mapping using fluorescent derivatives of two RGD peptides, a cyclic biotinylated (Bt)‐RGD peptide and a linear Rhodamine green‐labelled (RhoG)‐RGD peptide.6. The findings suggest that the binding sites for RGD peptide are represented by the αVβ3 integrin in the vasculature and some desquamated cells, whereas the majority of the desquamated cells bind Bt‐RGD via β1 integrins.7. These findings were further tested using cultured endothelial cells co‐incubated with leucocytes. When co‐incubation experiments were performed in the presence of cyclic RGD pentapeptide, the adhesion of HL‐60 cells to both control and hypoxic endothelial monolayers was significantly reduced.Presented at the Experimental Biology Symposium on the Role of Integrins in Acute Renal Failure, New Orleans, Louisiana, USA, 1997.
BATHTUB‐TYPE CURVES IN RELIABILITY AND BEYOND
Authors: Bebbington Mark , Lai Chin‐Diew , Zitikis Ričardas 
Published: August 2007

SummaryFinding optimal, or at least good, maintenance and repair policies is crucial in reliability engineering. Likewise, describing life phases of human mortality is important when determining social policy or insurance premiums. In these tasks, one searches for distributions to fit data and then makes inferences about the population(s). In the present paper, we focus on bathtub‐type distributions and provide a view of certain problems, methods and solutions, and a few challenges, that can be encountered in reliability engineering, survival analysis, demography and actuarial science.
NONPARAMETRIC METHOD FOR ESTIMATING THE SIZE OF AN OPEN POPULATION USING MARGINAL DATA FROM REPEATED MULTIPLE LISTS
Authors: Liu Danping , Yip Paul S. F. , Huggins Richard M. 
Published: August 2007

SummaryKernel smoothing methods are used to extend the Poisson log‐linear approach to the estimation of the size of population using multiple lists to an open population when the multiple lists are recorded at each time point. The data is marginal as only the lists at each time point are available and the transitions of individuals between lists at different time points are not observable. Our analysis is motivated by and applied to data on the number of drug addicts in the Hong Kong Special Administrative Region.
ETHEPHON (2‐CHLOROETHYLPHOSPHONIC ACID) EFFECTS ON SCENEDESMUS QUADRICAUDA (CHLOROPHYCEAE)1,2
Authors: Chapman Richard W. , Vance B. Dwain 
Published: August 2007

SUMMARYGrowth of Scenedesmus quadricauda (Turp.) Bréb. was significantly increased when the cultures were grown in Ethephon 68–241 (2‐chloroethylphosphonic acid) at concentrations of 0.001–1.0 μg · ml−1. At 0.1 μg · ml−1, Ethephon caused a significant increase in RNA levels on a dry weight basis. Total protein and DNA levels increased but not significantly. These data indicate that ethylene, the decomposition product of Ethephon at physiological pH, has some effect on the metabolism of algae.
PHYLOGENETIC RELATIONSHIPS OFCAULERPA(CHLOROPHYTA) BASED ON COMPARATIVE CHLOROPLAST ULTRASTRUCTURE1,2
Authors: Calvert Harry E. , Dawes Clinton J. , Borowitzka Michael A. 
Published: August 2007

SUMMARYThe ultrastructure of chloroplasts from 28 of the 73 species ofCaulerpaLamouroux (Chlorophyta, Caulerpales) has been studied to aid in interpreting phylogenetic relationships among the 12 recognized sections. Variations of systematic value include pyrenoid occurrence and fine structure, thylakoid architecture and amount of photosynthate storage. Comparisons of field and culture specimens indicate these characters are consistent. Chloroplast thylakoids are grouped into bands, with the distribution of bands differing among species. In the most common arrangement, bands are evenly distributed throughout the chloroplast. A few species show lateral displacement of bands whereas others have a majority of bands arranged at one end of the chloroplast. Starch is stored cither as one or two large grains (> 1 μm diam.) or numerous small grains (< 0.5 μm diam.). Electron‐transparent regions are common in other species in which chloroplasts rarely store starch. Simple, embedded pyrenoids are present in several species of section Sedoideae. An opaque region occurs in chloroplasts ofC. elongatawhich may represent an intermediate stage in the evolutionary loss of the pyrenoid. It is suggested that the chloroplast ofCaulerpaevolved, from a large, complex, pyrenoid‐containing organelle housing both photosynthetic and amylogenic functions, to a small, structurally simpler one, specialized for photosynthesis alone. A phylogeny of the 12 sections ofCaulerpais constructed, based on chloroplast evolution which agrees with an earlier morphology‐based hypothesis on the origin and evolution ofCaulerpa.
PHASED DIVISION OF PERIDINIUM CINCTUM F. WESTII (DINOPHYCEAE) AND DEVELOPMENT OF THE LAKE KINNERET (ISRAEL) BLOOM1,2
Authors: Pollingher Utsa , Serruya Colette 
Published: August 2007

SUMMARYThe yearly bloom of Peridinium cinctum f. westii (Lemm.) Lef. in Lake Kinneret is described and compared with the distribution of dinoflagellates in other freshwater bodies. The physical conditions required by the Wyatt and Horwood model do not fit the actual physical events accompanying the onset of the bloom. In situ measurements of the percentage of cells in division were undertaken to clarify various points about the internal dynamics of the population. The exponential increase of the population occurs when the diurnal percentage of cells in division is not higher than 10–15%. This percentage increases up to 45% in late February–March, but does not cause any increase of population. At this period, the loss rate is nearly equal to the rate of cell increase and is interpreted as massive mortality.
CACHONINA ILLDEFINA SP. NOV. (DINOPHYCEAE): CHLOROPLAST TUBULES AND DEGENERATION OF THE PYRENOID1
Authors: Herman Eliot Mark , Sweeney Beatrice M. 
Published: August 2007

SUMMARYA new species of the dinoflagellate genus Cachonina, C. illdefina sp. nov., was isolated from a red tide off El Capitan State Park, Santa Barbara County, California, in October 1973. The organism is light yellowgreen in color with deeply incised girdle and sulcal grooves. Electron microscopy of the organism, revealed a typical dinokaryotic nucleus. The chloroplasts of the organism are connected, and often contain microtubule‐like elements, 25 nm diam. The pyrenoids are characterized as excluding chloroplast thylakoids and ribosomes, although containing an amorphous matrix and numerous tubular invaginations from the cytoplasm. The pyrenoids become detached from the chloroplasts and degenerate into small vesicles. C. illdefina is not bioluminescent.
LONG‐TERM EFFECTS OF MANIPULATING LIGHT INTENSITY AND NUTRIENT ENRICHMENT ON THE STRUCTURE OF A SALT MARSH DIATOM COMMUNITY1,2
Authors: Michael J. Sullivan 
Published: August 2007

SUMMARYThe long‐term effects of manipulating light intensity and nutrient enrichment on the structural characteristics of a diatom community inhabiting the sediments beneath a pure stand of dwarfSpartina alternifloraLoisel. were investigated over a yearly cycle. Clipping or shading the cord grass cover, or phosphorus enrichment caused significant decreases in both species diversity (H') and the number of diatom species, whereas nitrogen enrichment only significantly decreased the latter parameter. Of the 105 diatom taxa identified, only 10 were restricted to certain of the 12 study areas; and of these, 8 occurred exclusively in the clipped habitats. An analysis of variance (light × nutrient × collection date) involving 19 of the most abundant taxa revealed that certain experimental treatments had significant effects on the relative abundances of each and every taxon. However, attempts to group taxa with similar response patterns proved unsuccessful because of the frequent significance of the 3‐way interaction term. Synthesis of these results with earlier work by the author showed that differences in structure of diatom communities inhabiting the sediments beneath the 3 dominant marsh grasses were not primarily caused by differences in reduction of light intensity by their grass canopies, and that clipping of the cord grass produced a shift in community structure towards that characteristic of a salt panne algal mat.
KINETICS OF SILICIC ACID UPTAKE AND RATES OF SILICA DISSOLUTION IN THE MARINE DIATOM THALASSIOSIRA PSEUDONANA1,2
Authors: Nelson David M. , Goering John J. , Kilham Susan S. , Guillard Robert R. L. 
Published: August 2007

SUMMARYTracer techniques using the stable isotope 30Si were used to measure rates of silicic acid uptake and silica dissolution in silicon replete and silicon depleted populations of 2 clones of the marine diatom Thalassiosira pseudonana Hasle & Heimdal. Uptake kinetics were describable using the Michaelis‐Menten equation for enzyme kinetics, and no threshold concentration for uptake was evident. The maximum specific uptake rate of the estuarine clone 3H (0.062–0.092 · h−1) was higher than that of the Sargasso Sea clone 13‐1 (0.028–0.031 · h−1), but half‐saturation constants for uptake by the 2 clones were not measurably different (0.8–2.3 μM for 3H; 1.4–1.5 μM for 13‐1). There was little or no light dependence of uptake in populations grown under optimal light conditions prior to the experiment. Exponentially growing populations released silicic acid to the medium by dissolution of cellular silica at rates ranging from 6.5 to 15% of the maximum uptake rate.
SEXUAL ISOLATION BETWEEN A EUROPEAN AND AN AMERICAN POPULATION OF ECTOCARPUS SILICULOSUS (PHAEOPHYTA)1
Authors: Müller Dieter G. 
Published: August 2007

SUMMARYSexual plants of Northeastern American Ectocarpus siliculosus (Dilhw.) Lyngb. have been isolated and cultured. Female gametes produce a volatile sex hormone acting on male gametes. Combination of American and European gametes shows that the initial step of the sexual reaction (attraction of male gametes) works normally, whereas interaction of cell surfaces and fusion of gametes is prevented.
KINETICS OF EXTRACELLULAR RELEASE IN AXENIC ALGAE AND IN MIXED ALGAL‐BACTERIAL CULTURES: SIGNIFICANCE IN ESTIMATION OF TOTAL (GROSS) PHYTOPLANKTON EXCRETION RATES1
Authors: Nalewajko C. , Dunstall T. G. , Shear H. 
Published: August 2007

SUMMARYIn axenic Chlorella pyrenoidosa Chick cultures, extracellular release was linear with time, but plateau‐type curves were obtained in cultures with added bacteria. Initial rates of excretion were identical in both, systems. Kinetics of extracellular release in axenic Anabaena flos‐aquae (Lyng.) Bréb. cultures were more complex than in Chlorella but the initial excretion rates were identical in axenic and mixed algal‐bacterial cultures. In lakewater, extracellular release kinetics resemble the pattern in mixed Chlorella‐bacteria cultures. An explanation is an initial lag in bacterial utilization of algal extracellular products. As a result, both in situ and in the laboratory, consecutive short, experiments give higher excretion rates than single long incubations. It is suggested that the former are close to total or gross extracellular release rates whereas the latter give net values, detecting only substances not, removed by heterotrophs.