bluuebunny/crossref_metadata_2025_split huggingface dataset:
Can Weakly Coordinating Anions Stabilize Mercury in Its Oxidation State +IV?
Authors: Riedel Sebastian , Straka Michal , Kaupp Martin 
Published: February 2005

AbstractWhile the thermochemical stability of gas‐phase HgF4 against F2 elimination was predicted by accurate quantum chemical calculations more than a decade ago, experimental verification of “truly transition‐metal” mercury(IV) chemistry is still lacking. This work uses detailed density functional calculations to explore alternative species that might provide access to condensed‐phase HgIV chemistry. The structures and thermochemical stabilities of complexes HgIVX4 and HgIVF2X2 (X−=AlF4−, Al2F7−, AsF6−, SbF6−, As2F11−, Sb2F11−, OSeF5−, OTeF5−) have been assessed and are compared with each other, with smaller gas‐phase HgX4 complexes, and with known related noble gas compounds. Most species eliminate F2 exothermically, with energies ranging from only about −60 kJ mol−1 to appreciable −180 kJ mol−1. The lower stability of these species compared to gas‐phase HgF4 is due to relatively high coordination numbers of six in the resulting HgII complexes that stabilize the elimination products. Complexes with AsF6 ligands appear more promising than their SbF6 analogues, due to differential aggregation effects in the HgII and HgIV states. HgF2X2 complexes with X−=OSeF5− or OTeF5− exhibit endothermic fluorine elimination and relatively weak interactions in the HgII products. However, elimination of the peroxidic (OEF5)2 coupling products of these ligands provides an alternative exothermic elimination pathway with energies between −120 and −130 kJ mol−1. While all of the complexes investigated here thus have one exothermic decomposition channel, there is indirect evidence that the reactions should exhibit nonnegligible activation barriers. A number of possible synthetic pathways towards the most interesting condensed‐phase HgIV target complexes are proposed.
Light and electron microscopic analysis of KChIP and Kv4 localization in rat cerebellar granule cells
Authors: Strassle Brian W. , Menegola Milena , Rhodes Kenneth J. , Trimmer James S. 
Published: February 2005

AbstractPotassium channels are key determinants of neuronal excitability. We recently identified KChIPs as a family of calcium binding proteins that coassociate and colocalize with Kv4 family potassium channels in mammalian brain (An et al. [2000] Nature 403:553). Here, we used light microscopic immunohistochemistry and multilabel immunofluorescence labeling, together with transmission electron microscopic immunohistochemistry, to examine the subcellular distribution of KChIPs and Kv4 channels in adult rat cerebellum. Light microscopic immunohistochemistry was performed on 40‐μm free‐floating sections using a diaminobenzidine labeling procedure. Multilabel immunofluorescence staining was performed on free‐floating sections and on 1‐μm ultrathin cryosections. Electron microscopic immunohistochemistry was performed using an immunoperoxidase pre‐embedding labeling procedure. By light microscopy, immunoperoxidase labeling showed that Kv4.2, Kv4.3, and KChIPs 1, 3, and 4 (but not KChIP2) were expressed at high levels in cerebellar granule cells (GCs). Kv4.2 and KChIP1 were highly expressed in GCs in rostral cerebellum, whereas Kv4.3 was more highly expressed in GCs in caudal cerebellum. Immunofluorescence labeling revealed that KChIP1 and Kv4.2 are concentrated in somata of cerebellar granule cells and in synaptic glomeruli that surround synaptophysin‐positive mossy fiber axon terminals. Electron microscopic analysis revealed that KChIP1 and Kv4.2 immunoreactivity is concentrated along the plasma membrane of cerebellar granule cell somata and dendrites. In synaptic glomeruli, KChIP1 and Kv4.2 immunoreactivity is concentrated along the granule cell dendritic membrane, but is not concentrated at postsynaptic densities. Taken together, these data suggest that A‐type potassium channels containing Kv4.2 and KChIP1, and perhaps also KChIP3 and 4, play a critical role in regulating postsynaptic excitability at the cerebellar mossy‐fiber/granule cell synapse. J. Comp. Neurol. 484:144–155, 2005. © 2005 Wiley‐Liss, Inc.
Neural control mechanisms of the pheromone‐triggered programmed behavior in male silkmoths revealed by double‐labeling of descending interneurons and a motor neuron
Authors: Wada Satoshi , Kanzaki Ryohei 
Published: February 2005

AbstractMale silkmoths, Bombyx mori, exhibit a characteristic zigzagging behavior consisting of straight‐line walking, zigzagging turns, and looping. The timing for shifting the turning direction is synchronized to the sideways head movements controlled by neck motor neurons (NMNs) including a cervical ventral NMN (cv1‐NMN). It has been suggested that this programmed behavior is instructed by two types of activity patterns descending from the brain and the thoracic ganglion: one is a phasic excitation and the other is a state‐dependent activity similar to the flipflop in electric memory circuits. These activities are shown by certain descending interneurons contained in two subsets of DNs, Group‐I and ‐II DNs. However, it is not yet well understood which DNs are directly related to instructing this behavior. In order to understand neural control mechanisms of this programmed behavior, we investigated the morphological relationship between these DNs and the cv1‐NMN, which is an index of this programmed behavior. We applied a double‐labeling technique combining backfilling of the cv1‐NMN and intracellular staining of single DNs. 3D confocal images revealed overlapping regions between the Group‐I, ‐II DNs and the cv1‐NMN. Group‐IIA and ‐IID, which showed typical flipflop activities, Group‐IIC DNs, which showed phasic excitation, and Group‐IB DNs, which showed long‐lasting inhibition had many overlapping regions on the cv1‐NMNs. Our results indicate that the programmed behavior is instructed by these types of DNs. J. Comp. Neurol. 484:168–182, 2005. © 2005 Wiley‐Liss, Inc.
Retinotectal transmission in the optic tectum of rainbow trout
Authors: Kinoshita Masae , Fukaya Masahiro , Tojima Takuro , Kojima Satoshi , Ando Hironori , Watanabe Masahiko , Urano Akihisa , Ito Etsuro 
Published: February 2005

AbstractRetinotectal transmission has not yet been well characterized at the cellular level in the optic tectum. To address this issue, we used a teleost, the rainbow trout, and characterized periventricular neurons as postsynaptic cells expected to receive the retinotectal inputs to the optic tectum. The somata of periventricular neurons are localized in the upper zone of the stratum periventriculare (SPV), whereas the lower zone of the SPV comprises the cell body layer of radial glial cells. Ca2+ imaging identified functional ionotropic glutamate receptors in periventricular neurons. We also cloned cDNAs encoding the NR1 subunit of N‐methyl‐D‐aspartic acid (NMDA) receptors and the GluR2 subunit of (±)‐α‐amino‐3‐hydroxy‐5‐methyl‐isoxazole‐4‐propionic acid (AMPA) receptors, and detected their mRNAs in periventricular neurons by in situ hybridization. The presence of the receptor subunit proteins was also confirmed in the dendrites of periventricular neurons by immunoblotting and immunohistochemistry. On the other hand, radial glial cells in the lower zone of the SPV did not respond to glutamate applications, and mRNA and immunoreactivities of ionotropic glutamate receptors were not detected in glial cells. The present findings suggest that glutamatergic transmission at synapses between retinotectal afferents and periventricular neurons is mediated by the functional NMDA and AMPA receptors. J. Comp. Neurol. 484:249–259, 2005. © 2005 Wiley‐Liss, Inc.
Growth hormone expression in the perinatal and postnatal rat lung
Authors: Beyea Jason A. , Olson David M. , Harvey Steve 
Published: February 2005

AbstractIt is now established that the lung is a target site for pituitary growth hormone (GH) action, because pathophysiological states of pituitary GH excess and deficiency are associated with impaired pulmonary function. The onset of lung development and differentiation is, however, before the ontogenic differentiation of pituitary somatotrophs. GH may be involved, nevertheless, in lung development, because it is present in extrapituitary tissues of preimplantation mouse embryos and in the lung buds of embryonic chickens. The possibility that GH may be expressed in the rat lung during fetal and neonatal development, therefore, has been assessed. GH mRNA was detected in the lung, and its 693‐bp sequence was identical to that in the pituitary gland. By in situ hybridization, this transcript was found to be abundantly expressed in the lungs of embryonic day (ED) 17 rats in mesenchymal, mucosal epithelial, and smooth muscle cells. This transcript was expressed in neonates until at least day 14 postnatally and was localized to type I and II epithelial cells and to pulmonary tissue macrophages and alveolar macrophages. GH immunoreactivity paralleled GH mRNA cellular localization throughout the time course studied. This immunoreactivity was specific and was lost after antibody preabsorption. The perinatal and postnatal lung is, therefore, an extrapituitary site of GH gene expression during development. Given that the GH receptor is present in the lung from early development, lung GH may have autocrine and/or paracrine roles in lung growth or differentiation or in pulmonary function. Developmental Dynamics 232:1037–1046, 2005. © 2005 Wiley‐Liss, Inc.
Retinoic acid down‐regulates Tbx1 expression in vivo and in vitro
Authors: Roberts Catherine , Ivins Sarah M. , James Chela T. , Scambler Peter J. 
Published: February 2005

AbstractBoth Tbx1 and retinoic acid (RA) are key players in embryonic pharyngeal development; loss of Tbx1 produces DiGeorge syndrome‐like phenotypes in mouse models as does disruption of retinoic acid homeostasis. We have demonstrated that perturbation of retinoic acid levels in the avian embryo produces altered Tbx1 expression. In vitamin A‐deficient quails, which lack endogenous retinoic acid, Tbx1 expression patterns were disrupted early in development and expression was subsequently lost in all tissues. “Gain‐of‐function” experiments where RA‐soaked beads were grafted into the pharyngeal region produced localized down‐regulation of Tbx1 expression. In these embryos, analysis of Shh and Foxa2, upstream control factors for Tbx1, suggested that the effect of RA was independent of this regulatory pathway. Real‐time polymerase chain reaction analysis of retinoic acid‐treated P19 cells showed a dose‐dependent repression of Tbx1 by retinoic acid. Repression of Tbx1 transcript levels was first evident after 8–12 hr in culture in the presence of retinoic acid, and to achieve the highest levels of repression, de novo protein synthesis was required. Developmental Dynamics 232:928–938, 2005. © 2005 Wiley‐Liss, Inc.
Green Light Luminescence from ZnO/Dodecylamine Mesolamellar Nanocomposites Synthesized by Self‐Assembly
Authors: Wang Yu‐de , Zhang Shuo , Wu Xing‐hui 
Published: February 2005

AbstractThe synthesis, structural characterization and optical properties of a semiconducting zinc oxide based dodecylamine surfactant, mesolamellar zinc oxide/surfactant nanocomposite (Zn‐L) are described. XRD and TEM results showed the formation of a lamellar mesostructure with two layer spacings ca. 28 Å. A red‐shift in the absorption band edge of absorption spectrum and the green light photoluminescence of the resulted nanocomposite were observed at room temperature. The red‐shift of the absorption band edge and the room temperature photoluminescence (RTPL) of the Zn‐L nano‐composite might be induced by the dielectric confinement effect and the interfacial interaction between the ZnO and the surfactant, respectively. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
SH‐SS relationships in Ehrlich ascites tumor cells exposed to edathamil
Authors: Dipaolo Joseph A. 
Published: February 2005

AbstractBy means of an amperometric titration method, the acid soluble sulfhydryl, protein sulfhydryl, and disulfide content of Ehrlich ascites tumor cells were determined before and after exposure to edathamil. No statistically significant differences were found between exposed and control groups. The addition of edathamil did not alter oxygen utilization. Changes in the viscosity of cell cytoplasm were determined by observation of the movement of lipoid granules with a phase contrast microscope following high speed centrifugation. The decrease in viscosity observed with edathamil could be prevented by the addition of glutathione simultaneously or 30 minutes later. A shift from intermolecular SS to intramolecular SS during sol‐gel transformation is suggested by the increased viscosity following the addition of glutathione.
Osmoregulation in the amphibian egg the influence of calcium
Authors: Berntsson Karl‐Erik , Haglund Birgit , Løvtrup Søren 
Published: February 2005

AbstractDeterminations of the permeability coefficient for water show that the osmotic behavior of amphibian eggs (ovarian and coelomic eggs from Rana temporaria) cannot be accounted for by this factor alone. Comparison of the cortical stiffness of coelomic eggs with vitelline membrane in iso‐ and hypotonic solutions indicate that a mechanical tension develops under hypotonic conditions, strong enough to resist osmotic swelling.In Ca++‐free media preservation of this tension is interfered with, but the effect is observed only after exposure for some hours.Ca++ does not change the diffusion coefficient for water in the egg cytoplasm, nor the permeability coefficient for water through the cell membrane. Neither is the Young's modulus for the vitelline membrane influenced. A slight effect of Ca++ on the cortical stiffness of naked coelomic eggs was observed. In hypotonic Ca++‐free media no resistance to swelling develops in these eggs, and they disintegrate after a rather short time.To determine the permeability to water the rate of D2O — H2O exchange was measured with the Cartesian diver balance. The stiffness was determined with a cell elastimeter described by Mitchison and Swann, and the osmotic swelling was determined by measuring the egg diameter with an eyepiece screw micrometer.
Effect of ethanol on electrolyte transport and electrogenesis in animal tissues
Authors: Israel‐Jacard Y. , Kalant H. 
Published: February 2005

AbstractEthanol 0.087 M (400 mg/100 ml) did not affect the initial loss of K+ from guinea‐pig brain cortex slices at the start of incubation, but significantly inhibited the subsequent reaccumulation of K+. Ethanol 0.098 M (450 mg/100 ml) also significantly inhibited the active reaccumulation of K+ by pre‐cooled rabbit kidney cortex slices.In vivo experiments with an electric eel indicated that ethanol in concentrations of 100 to 700 mg/100 ml (22 to 152 mM) significantly diminished the frequency of spontaneous low‐voltage electrogenesis.These findings, together with others in the literature, suggest that ethanol inhibits the active transport of cations by many types of cell, at concentrations relevant to non‐lethal intoxication.
Calcium uptake in glycerol‐extracted rabbit psoas muscle fibers. I. Biochemical properties and conditions for uptake
Authors: Elison C. , Fairhurst A. S. , Howell J. N. , Jenden D. J. 
Published: February 2005

AbstractRabbit psoas muscle fibers, extracted in 50% (w/v) glycerol for 20 hours, concentrate up to 300 μmol calcium per gm protein when placed in a suitable electrolyte environment at pH 6.5 containing ATP and 47Ca in the form of a Ca/EGTA metal buffer system. This property is retained at [Ca++] down to 2 × 10−8 M, the lowest studied. The kinetics of Ca pickup are consistent with a mathematical model based on diffusion of Ca as the rate‐limiting factor. The pickup is dependent upon ATP and is increased by inclusion of CP or PEP. It is promoted by oxalate, fluoride, phosphate and pyrophosphate, which share the property of forming relatively insoluble calcium salts. Ability to concentrate calcium disappears on prolonged extraction in glycerol and after preincubation with desoxycholate.These properties are similar to those previously described for a granular fraction of muscle homogenates, and it is concluded that both are probably attributable to functional remnants of sarcoplasmic reticulum.
Studies on the transport of carbohydrate in Crithidia luciliae
Authors: Min Hong S. 
Published: February 2005

AbstractThe entrance of carbohydrates into the cells of C. luciliae has been studied, using the non‐utilizable monosaccharides: L‐sorbose, D‐xylose, L‐xylose, D‐arabinose, L‐arabinose, L‐rhamnose, D‐lyxose, D‐2‐deoxyglucose, and L‐fucose; all nine sugars entered the cell. At 0.5 mM external concentration the rate of increase in intracellular concentration is constant for all sugars until the intracellular concentrations equal or exceed the extracellular concentration. At 20 mM external concentration, the rate of increase of intracellular concentration decreases continuously and the maximum intracellular concentration never exceeds the extracellular concentration. There is competition between monosaccharides presented simultaneously to the cells and the transport mechanism shows enormously greater affinity for glucose than for other monosaccharides. The rate of carbohydrate entrance is inhibited 50% and 70% by KCN(10−4 M) and DNP(10−5 M) respectively at 0.5 mM external concentrations. However, these inhibitors do not affect transport from external concentrations of the order of 0.02 M. These data are interpreted as indicating two mechanisms for carbohydrate entrance: (a) an active transport mechanism, active at low external concentration and dependent upon a supply of metabolic energy; (b) facilitated diffusion, of importance only at high external concentrations. These results are compared with those reported in the literature for other types of cells.
Absorption of fat in the alimentary canal of Tilapia mossambica (Peters) (Teleostei)
Authors: Sivadas P. 
Published: February 2005

AbstractStudies on the absorption of fat in Tilapia mossambica point out the existence of a differential absorptive behavior in the different limbs of intestine. It appears that the relative increase in fat absorption in the anterior limb of the intestine is dependent on its functional status. It has also been pointed out that the sudanophilic lipid in its particulate form is transferred from the lumen of the intestine to the absorptive cell through the spindle shaped canals.
Limiting factors involved in CO2 production by starved and X‐irradiated starved yeast cells
Authors: Spoerl Edward , Doyle R. J. , Thompson M. E. 
Published: February 2005

AbstractStudies of reduced CO2 production by starved yeast cells were carried out to localize the site limiting this process and responsible for a greater production by irradiated cells. Cell‐free extracts prepared before and after starvation of cells, and from irradiated and unirradiated cells, showed similar hexokinase activity and produced similar amounts of CO2. These results demonstrated that rate limiting glycolytic enzymes did not decay during starvation, were not induced during a lag period in CO2 production which could be overcome by glucose incubation, and were not responsible for differences in CO2 production between irradiated and unirradiated cells. Possible limiting factors involved in these differences include glucose transport as a consequence of differential decay during starvation, restricted cofactor synthesis and an enzymic binding or compartmentalization.
Pressure‐temperature effects on the form‐stability and movements of Euglena gracilis var. Z.
Authors: Byrne John , Marsland Douglas 
Published: February 2005

AbstractThe phytoflagellate, Euglena gracilis var Z, maintained in a chemically defined culture medium, was subjected to various high hydrostatic pressures (10,000–15,000 psi) at various temperatures (15° 20° and 25°C). The effects on form stability, locomotion, euglenoid movement and flagellatory activity were observed at various times after the application of pressure.The pressure‐temperature relations of form stability clearly show that the supporting gel structures of the cell, presumably the peripheral gelated cytoplasm and the pellicle, may be identified as Type II systems in the Freundlich classification, since they undergo solational weakening with increasing pressure and with decreasing temperature. The gelational state of these structures appears to be unusually high, however, since at each given temperature, an usually high intensity of pressure is required to produce an observable loss of stability, i.e. a rounding up of the normally elongate cells.Flagellatory movement continued even at the highest pressure, but locomotion was abolished in all rounded and partly rounded individuals. Euglenoid movement ceased at relatively lower pressure (about 10,000 psi).The rounding of the euglena, even at maximum pressures, was not accompanied by any cytolysis. In this respect, euglena resembles amoeba and other sarcodinans, rather than paramecium and other ciliates.Euglena exhibited a rapid transient post‐pressure contraction, similar to that which has been described in several other protistan forms. No irreversible changes were observed. Normal form and activity reappeared in almost all specimens within about five minutes, subsequent to decompression.
Red Cell and plasma sodium and potassium changes in the San Diego pocket mouse during hibernation
Authors: Andrus William DeW. , Starr Stuart E. , Strathmann Richard R. 
Published: February 2005

AbstractAs compared to that of active animals, blood from P. fallax torpid at an ambient temperature (TA) of 15°C (hibernation) shows a decrease in red cell K and increases in cell Na and plasma K, and analyses of blood from animals hypothermic at TA = 25°C (aestivation) suggest increases in cell Na and plasma K. Blood electrolyte metabolism of this hibernating rodent shows no special resistance to hypothermia.
The influence of rat and frog liver enzymes on the hydrolysis of ortho and pyrophosphoric esters of thiamine
Authors: Singer‐Altbeker Rina , Ber Artur 
Published: February 2005

AbstractHomogenates of rat and frog liver were incubated with ThDP and ThMP at different pHs.The products of hydrolysis were identified by paper chromatography.In experiments carried out at pH 9 with ThDP as substrate in the presence of rat liver, the spot corresponding to Th did not appear on the chromatogram. This was in contrast with parallel experiments with frog liver. ThMP from commercial source behaved differently toward enzymatic decomposition than ThMP originating from hydrolysis of ThDP. Attempts have been made to explain these differences.