bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential localization of cytoplasmic myosin ii isoforms a and b in avian interphase and dividing embryonic and immortalized cardiomyocytes and other cell types in vitro
Authors: Conrad Abigail H. , Conrad Gary W. , Jaffredo Thierry 
Published: February 2005

AbstractTwo principal isoforms of cytoplasmic myosin II, A and B (CMIIA and CMIIB), are present in different proportions in different tissues. Isoform‐specific monoclonal and polyclonal antibodies to avian CMIIA and CMIIB reveal the cellular distributions of these isoforms in interphase and dividing embryonic avian cardiac, intestinal epithellal, spleen, and dorsal root ganglia cells in primary cell culture. Embryonic cardiomyocytes react with antibodies to CMIIB but not to CMIIA, localize CMIIB in stress‐fiber‐like ‐structures during interphase, and markedly concentrate CMIIB in networks in the cleavage furrow during cytokinesis. In contrast, cardiac fibroblasts localize both CMIIA and CMIIB in stress fibers and networks during interphase, and demonstrate slight and independently regulated concentration of CMIIA and CMIIB in networks in their cleavage furrows. V‐myc‐immortalized cardiomyocytes, an established cell line, have regained the ability to express CMIIA, as well as CMIIB, and localize both CMIIA and CMIIB in stress fibers and networks in interphase cells and in cleavage furrows in dividing cells. Conversely, some intestinal epithelial, spleen, and dorsal root ganglia interphase cells express only CMIIA, organized primarily in networks. Of these, intestinal epithelial cells express both CMIIA and CMIIB when they divide, whereas some dividing cells from both spleen and dorsal root ganglia express only CMIIA and concentrate it in their cleavage furrows. These results suggest that within a given tissue, different cell types express different isoforms of CMII, and that cells expressing either CMIIA or CMIIB alone, or simultaneously, can form a cleavage furrow and divide.
Manipulation of bovine sperm metabolism and motility using anoxia and phosphodiesterase inhibitors
Authors: Schoff Patrick K. , First Neal L. 
Published: February 2005

AbstractBovine sperm that were subjected to extended anoxia (2.5 h) in the absence of glycolytic substrates then diluted into oxygenated medium were immotile but metabolically active, producing ATP from lactate via oxidative phosphorylation. In response to anoxia sperm ATP titers dropped from 15–20 μmoles/108 cells to 1–2 μmoles/108 cells in the first 5 min then remained extremely low until reoxygenation. Cyclic AMP titers declined slowly over the anoxic period, but did not show the same scale of depression as ATP. After dilution and re‐oxygenation ATP recovered to pre‐anoxia levels within 1 min, and cAMP rose to about the pre‐anoxia levels. However, motility, which varied quantitatively and qualitatively between ejaculates prior to anoxic treatment, was substantially depressed after extended anoxia in all cases; progressive motility was almost non‐existent in post‐anoxic sperm. Addition of isobutylmethylxanthine or Cibacron Blue F3GA, both putative phosphodiesterase inhibitors, stimulated a transient peak of cAMP, which was accompanied by motility stimulation. These techniques provide a protocol to manipulate and dissect the biochemical pathways of motility initiation in mammalian sperm.
Role of the cytoskeleton in the reaction of fibroblasts to multiple grooved substrata
Authors: Wójciak‐Stothard B. , Curtis A. S. G. , McGrath M. , Sommer I. , Wilkinson C. D. W. , Monaghan W. 
Published: February 2005

AbstractThe role of the cytoskeleton and cell attachments in the alignment of baby hamster kidney fibroblasts to ridge and groove substratum topography was investigated using confocal scanning microscopy. This was carried out with normal cells and cells treated with the cytoskeleton modifiers cytochalasin D, colcemid, and taxol. Actin was localised with fluorescent phalloidin. Tubulin, Vinculin, and intracellular adhesion molecule‐1 were visualised by indirect immunofluoresence. The spreading, elongation, and orientation of the cells after 24 h of culture in these conditions were measured on grooves of 5, 10, and 25 μm width and 0.5, 1, 2, and 5 μm depth. We have also observed events over the first 30 min of cell attachment. Five minutes after cell attachment, F‐actin condensations were seen close to the intersection of groove wall and ridge top, that is, at a topographic discontinuity. The condensations were often at right angles to the groove edge and showed a periodicity of 0.6 μm. Vinculin arrangement at the early stages of cell spreading was similar to that of actin. Organisation of the microtubule system followed later, becoming obvious at about 30 min after cell plating. The Curtis and Clark theory (that cell react to topography primarily at lines of discontinuity in the substratum by actin nucleation) is supported by these results. The use of cytoskeletal poisons did not entirely abolish cell reaction to grooves. Colocemid increased cell spreading and reduced cell orientation and elongation. Cytochalasin D reduced cell spreading, orientation, and elongation. Taxol reduced cell elongation but did not affect cell spreading and orientation. We conclude that the aggregation of actin along groove/ridge boundaries is a primary driving event in determining fibroblast orientation on microgrooved substrata.
cAMP/ATP relationship in the activation of trout sperm motility: Their interaction in membrane‐deprived models and in live spermatozoa
Authors: Cosson Marie‐Paule , Cosson Jacky , Andrè Françoise , Billard Roland 
Published: February 2005

AbstractLive trout spermatozoa initiate flagellar motility for only a short period (30 sec at 18°C) during which their mean beat frequency decreases steadily from 60 to 20 Hz. Motility then stops abruptly. Investigations of the activation of movement in demembranated sperm points to cyclic‐AMP being necessary for reactivation (half effect at 0.5μm) in some conditions. cAMP acts mainly by increasing the percentage of motile cells and not the beat frequency (BF) of the flagellar axoneme. Dibutyryl cAMP does not initiate movement or prolong motility of live sperm.The initiation of movement of demembranted trout sperm was investigated in various incubation conditions relative to previous phases of in vivo movement and to ATP concentration. In the absence of cAMP and in the presence of ATP lower than 25 μM, all sperm celi models were active with BF up to 15‐20 Hz whatever their previous physiological condition. In contrast, at ATP concentrations above 100 μM, the fraction of active spermatozoa decreased proportionally but the BF of the active ones increased so that, at 1 mM ATP up to 20 μM restored activity to 100% sperm models with a similar BF of 65 Hz.At ATP concentrations higher than 25 μM, cAMP was necessary in a concentration dependent manner in the reactivation, but not in the demembranation meduim. This dependence was found to be unrelated to a previous in vivo phase of movement. The antagonistic effects of ATP vs. cAMP were tested at various concentrations of both nucleotides: the apparent affinity for cAMP, measured as the concentration restoring movement of 50% cell models, was decreased from 15 nM at 0.1 mM ATP to 0.5 μM at 1 mM ATP; conversely, the affinity for ATP, measured as the concentration giving rise to the half maximal beat frequency, was not significautly affected when the concentration of cAMP was raised to 0.5 mM. Preincubation with phosphodiesterase (PDE) resulted in motility of 100% of sperm models even at low ATP concentration. This tends to show that cAMP must be constantly present to sustain motility.
Suppression of syntheses of high molecular weight nonmuscle tropomyosins in macrophages
Authors: Nakamura Yohko , Sakiyama Shigeru , Takenaga Keizo 
Published: February 2005

AbstractIn mouse fibroblasts, at least five TM isoforms are identified and they can be grouped into the high (TM1, TM2, and TM3) and low molecular weight TM isoforms (TM4 and TM5). Suppression of one of the high molecular weight tropomyosin (TM) isoforms in nonmuscle cells is implicated to be one of the causes for disorganization of actin microfilament bundles and subsequent changes in cell motility and cell shape. In this study, we studied the expression of tropomyosin isoforms in macrophages that exhibit high motility and ability to change cell shape. Two‐dimensional gel electrophoresis followed by Western blot analysis using polyclonal anti‐TM antiserum revealed that the high molecular weight TM isoforms were lacking in both resident and activated mouse peritoneal macrophages. Analyses of newly synthesized TM isoforms, Northern blot analyses using isoform‐specific cDNA probes, and immunostaining with monoclonal anti‐TM antibody that recognizes only the high molecular weight TM isoforms also demonstrated that the syntheses of the high molecular weight TM isoforms (TM1, TM2, and TM3) were completely suppressed, whereas the low molecular weight TM isoforms (TM4 and TM5) were expressed in macrophages. These results indicate that macrophages intrinsically lack the high molecular weight TM isoforms. In order to obtain information about cellular localization of the low molecular weight TM isoforms in macrophages, they were immunostained with polyclonal anti‐TM antiserum that recognizes both the high and low molecular weight TM isoforms. The results showed that the low molecular weight TM isoforms were co‐localized with F‐actin in punctate and short fibrous structures. In addition, we performed in situ hybridization analysis to examine localizations of the TM mRNAs in fibroblasts and macrophages. The results showed that TM mRNAs were localized throughout the cytoplasm. © 1995 Wiley‐Liss, Inc.
Actin filaments in honeybee‐flight muscle move collectively
Authors: Trombitéas K. , Pollack G. H. 
Published: February 2005

AbstractTo investigate the pattern of actin‐filament translation in the intact myofibrillar matrix, we carried out electron micrographic experiments on the “rigor‐stretch” model of insect‐flight muscle. In this model, thin filaments are mechanically severed from their connections to the Z‐line and may then slide freely over the myosin filament when activated. The model is similar to the in vitro motility assay in that untethered actin filaments slide over myosin, but here the natural filament lattice is retained: sliding takes place through the lattice of thick filaments. We find, in this model, that while the extent of thin filament translation is variable from sarcomere to sarcomere, filaments never translate far enough to enter the opposite I‐band. Unlike the in vitro motility assay, where the actin filament translates over the entire thick filament even with “incorrectly” polarized crossbridges as the sole driver, in this intact filament‐lattice model, cross‐bridges are apparently unable to move filaments in both directions. We also find that the pattern of filament translation is collective. Although the extent of translation may vary among sarcomeres, in any given half‐sarcomere all actin filaments translate by the same degree. Further, the extent of translation is is the same in both halves of a given sarcomere. In rare instances where the extent of translation exhibited a transverse gradient across the myofibrillar half‐sarcomere, the gradient was similar on both sides of the sarcomere. Filament translation within the sarcomere is thus collective. Some mechanism ensures that nearby but distinctly separated actin filaments move together and that cooperative‐like behavior therefore extends to the supramolecular level.
Nebulette: A 107 kD nebulin‐like protein in cardiac muscle
Authors: Moncman Carole L. , Wang Kuan 
Published: February 2005

AbstractA 107‐kD protein has been identified in primary cultures of chicken embryonic cardiomyocytes by immunoprecipitations with certain anti‐nebulin monoclonal antibodies (mAbs). These mAbs, prepared against a fragment of human skeletal muscle nebulin located near the carboxyl terminus, detect a 107‐kD protein in extracts of adult chicken heart, adult mouse heart, and adult rabbit heart by immunoblot analysis. A partial cDNA corresponding to this protein has been isolated by immunological screening of a chicken heart cDNA expression vector library. The partial cDNA encodes a 380‐amino acid open reading frame composed entirely of nebulin‐like 35‐residue modules marked by the highly conserved sequence motifs: SXXXYK and TPD. The open reading frame exhibits 60–85% homology with skeletal muscle nebulins from a variety of species. This cDNA recognizes an ˜8‐kb transcript in cardiac RNA and does not hybridize to skeletal muscle RNAs by northern analysis. Immunofluorescence localization of this nebulin‐like protein in primary cultures of chicken cardiomyocytes and embryonic chicken cardiac myofibrils indicates that the protein is localized to the I‐Z‐I complex of the myofibrils, extending approximately 25% of the thin filament length. Comparisons of the distribution of this protein relative to actin, myosin, and titin in spreading cardiomyocytes suggest that the cardiac nebulin‐like protein becomes aligned with the nascent myofibrils early during myofibrillogenesis. To distinguish this petite nebulin‐like protein from the 600–900 kD skeletal muscle nebulin, we have named it nebulette. © 1995 Wiley‐Liss, Inc.
Polarity and nucleation of microtubules in polarized epithelial cells
Authors: Meads Tim , Schroer Trina A. 
Published: February 2005

AbstractMicrotubules oriented in the apicobasal axis of columnar epithelial cells arranged with a uniform polarity with minus ends toward the apical surface, suggesting that these cytoskeletal filaments might serve as a substrate for polarized movement of membrane vesicles within the cell. It is not known whether hepatocytes, a cuboidal epithelium in which transcellular transport is a requisite step in normal apical membrane biogenesis, contain microtubules arranged with a similar polarity. In the present study, we explore the question of microtubule polarity and possible mechanisms for nucleation in the epithelial cell lines WIF‐B (hepatocyte), Caco‐2 (intestine), and Madin‐Darby canine kidney (MDCK). Caco‐2 microtubules in the apicobasal axis had uniform polarity with minus ends nearest the apical surface. After cold and nocodazole‐induced depolymerization, microtubule regrowth initiated in the apical region in all three cell types. The apex of WIF‐B and Caco‐2 cells contained two pools of γ‐tubulin: one associated with centrosomes and the other delocalized under the apical membrane. Non‐centrosomal γ‐tubulin was present in complexes that sedimented between 10S and 29S; both forms could bind microtubules. The presence of both centrosomal and noncentrosomal γ‐tubulin in apical cytoplasm suggests multiple mechanisms by which microtubule nucleation might occur in epithelial cells. © 1995 Wiley‐Liss, Inc.
Silicon crystal growth from the melt: Analysis from atomic and macro scales
Authors: Kakimoto K. , Liu L. , Kitashima T. , Murakawa A. , Hashimoto Y. 
Published: February 2005

AbstractThe effect of impurity concentration on thermal conductivity of natural and isotope silicon by using equilibrium molecular dynamics simulation is investigated. It was found that the concentrations of the impurities such as boron, phosphor and arsene play an important role in the propagation of phonons in silicon crystals. It was also clarified that a mass difference of impurities and host crystals results in degradation of thermal conductivity of silicon. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Study of microindentation hardness of different planes of gadolinium calcium oxyborate single crystals
Authors: Sangwal K. , Kłos A. 
Published: February 2005

AbstractThe microhardnessHVof gadolinium calcium oxyborate single crystals has been investigated on the planes of different orientations as a function of applied load and indenter orientation. It was found that: (1) on the (010) plane microhardness is practically independent of indenter orientation and indenter diagonald, and is constant, (2) on the (100) and (001) planes both normal and reverse indentation size effects occur in the indentation diagonal intervals below and above a critical valuedc, and (3) at loads exceeding about 30 g all indentation impressions are accompanied by cracks, the formation of which does not depend on the orientations of indentations. The observations of indentation size effect were analysed by using Hays‐Kendall's approach, the proportional specimen resistance model of Li and Bradt, and the strain gradient plasticity theory. The analysis of the data revealed that: (1) indentation size effect on the different faces of gadmium calcium oxyborate may be explained satisfactorily by the proportional specimen resistance model and the strain gradient plasticity theory, (2) the models explain the dependence of microhardnessHVon indentation diagonaldin the ranged<dc, while for deformation atd>dcthe excess indentation pressure, and the energy associated with it, is expended in creating and developing radial and lateral cracks around indentations, and (3) in the ranged<dcthe load‐independent microhardnessH0on different planes changes in the sequence:H0(010) >H0(001) >H0(100), and may be explained in terms of the process of rupturing of successive planes perpendicular to the direction of penetration of indenter. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Instability of Al‐Cu‐Co single quasicrystals at low temperature
Authors: Bogdanowicz W. 
Published: February 2005

AbstractDecomposition process of the Al‐Cu‐Co single quasicrystals (falling apart into small pieces) after annealing at 100 °C for 20 h was studied by X‐ray topography, high‐resolution electron microscopy, X‐ray diffractometry and optical microscopy. It was found that the decomposition of the single quasicrystals is preceded by the creation of a large number of antiphase microdomains and the deformation of the clusters occurs in the two‐fold directions of [01$\bar 1$00] type. The decomposition begins with the propagation of cracks in the directions of [01$\bar 1$00] type. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
X‐ray characterization of thick GaN layers grown by HVPE
Authors: Korbutowicz R. , Kozłowski J. , Dumiszewska E. , Serafińczuk J. 
Published: February 2005

AbstractThe crystallographic structures of the various Metalorganic Vapour Phase Epitaxy (MOVPE) thin GaN epitaxial layers deposited on (00.1) sapphire substrates are described and compared with the structural properties of the thick gallium nitride layers deposited by Hydride Vapour Phase Epitaxy (HVPE) on the top of them. The crystallographic structure and the quality of epitaxial GaN layers obtained in this way are determined. Additionally thick HVPE GaN layers deposited on these composite substrates (MOVPE‐GaN/sapphire) are compared with the thick HVPE GaN layers grown directly on sapphire substrates. It was found that HVPE thick GaN epilayers on sapphire are comparable with the HVPE thick GaN layers deposited on composite substrates. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Evolution of stress and structure in Cu thin films
Authors: Chocyk D. , Zientarski T. , Proszynski A. , Pienkos T. , Gladyszewski L. , Gladyszewski G. 
Published: February 2005

AbstractEvolution of stresses developing in Cu thin films during and after deposition by thermal evaporation in UHV system is studied. Thin films were deposited on 100 µm thick Si substrate at room temperature. Deposition rates for the films were changed between 0.2 Å/s and 2.0 Å/s, while the total thickness was changed from 7.7 nm to 155 nm. Deformation analysis of crystalline lattice and microstructure was performed by x‐ray diffraction measurements (θ‐2θ scans, “sin2ψ” method). The surface morphology of film was studied by atomic force microscopy. The average stress in the films was determined by measuring the radius of curvature of samples. For thin films three stages of stress evolution (compressive, tensile and compressive) were we distinguished. This behavior is characteristic for materials with a Volmer‐Weber mode. A three‐dimensional molecular dynamics technique was applied for simulating the stress calculation during thin film growth. The results obtained from the simulation are consistent with the experimental results. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ontogeny of urine preference and its relationship to NH4Cl preference and sodium hunger in suckling rat pups
Authors: Leshem Micah , del Canho Sonia 
Published: February 2005

AbstractWe chart the postnatal ontogeny of urine preference in the suckling rat. Twelve‐day‐old sucklings, when offered urine, NH4Cl, or NaCl, ingest more urine and NH4Cl than NaCl. When rendered sodium hungry by ivc renin or by sodium depletion, these sucklings prefer urine and NH4Cl to NaCl, dilute urine, or an NaCl and KCl mineral mix equimolar to urine; however, by 18 days of age, urine and NH4Cl are no longer preferred to NaCl. Hence, urine preference in the suckling may be specific and preparatory for the variety of purposes urine preference serves in the adult rat, and it might guide the pup to urinary sodium in the nest. Since preference for urine and NH4Cl covary during postnatal development, the high preference for NH4Cl in midterm sucklings might be because its ammonium flavor is similar to urine. © 2005 Wiley Periodicals, Inc. Dev Psychobiol 46: 111–117, 2005.
Upper and lower body functional asymmetries in the newborn: Do they have the same lateral biases?
Authors: Domellöf Erik , Hopkins Brian , Rönnqvist Louise 
Published: February 2005

AbstractIt is still an open question as to whether functional asymmetries in the human newborn derive from a single lateralized system or multiple subsystems based on different neural mechanisms. In the present study, asymmetries in head turning were compared to those in leg movements during stepping and placing, with the latter also being related to differences in leg mass. The effects of an active versus an inactive state or condition were examined for all three behaviors. No overall lateral biases were found for head turning or for the first foot to move in stepping and placing, and there were no concordances among them; however, there was an asymmetry in that the left foot had a shorter onset latency when compared to the right foot for both stepping and placing. Findings are discussed in terms of what they imply about underlying neural systems that have a bearing on expressions of newborn laterality, and also with regard to the impact of methodological differences in this area of study. © 2005 Wiley Periodicals, Inc. Dev Psychobiol 46: 133–140, 2005.
Ontogeny of the transition from killer to caregiver in dwarf hamsters (Phodopus campbelli) with biparental care
Authors: Vella Emily T. , Evans Christopher C. D. , Ng Michelle W. S. , Wynne‐Edwards Katherine E. 
Published: February 2005

AbstractBiparental Phodopus campbelli and uniparental P. sungorus juvenile litters (2 males, 2 females) both consumed amniotic fluid and placenta during the birth of younger siblings. Three days later, P. campbelli juveniles were most responsive to a displaced younger sibling. Thus, P. campbelli are responsive to pups as juvenile alloparents and as new parents; however, at intervening ages, infanticidal attack (bite) was seen. At 5, 7, 9, 11, or 13 weeks of age, male and female P. campbelli were given a 5‐min test with an unrelated, 3‐day‐old, anesthetized pup. Females attacked more often than males, yet pup‐retrieval rates did not differ. Female aggression increased with age and was replaced by retrieval behavior 3 days after parturition. Male attack ceased after a birth, but parental behavior did not increase, remaining below the rate for new fathers tested with their own awake pup. Over repeated testing, behavior in one test did not predict behavior in another. Transitions from caregiving alloparent to infanticidal adult and back to parental care were clear in females, but less discrete with this stimulus paradigm in these highly paternal males. © 2005 Wiley Periodicals, Inc. Dev Psychobiol 46: 75–85, 2005.