bluuebunny/crossref_metadata_2025 huggingface dataset:
Carbon—Carbon Bond Cleavage Reaction Using Metallocenes
Authors: Takahashi Tamotsu , Kanno Ken‐ichiro
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
Carboranes: From Small Organoboranes to Clusters
Authors: Berndt Armin , Hofmann Matthias , Siebert Walter , Wrackmeyer Bernd
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
Efficiency in Nonenzymatic Kinetic Resolution
Authors: Vedejs Edwin , Jure Mara
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
Chiral Catalysts in the Stereoselective Synthesis of Pyrrolidine Derivatives via Metallo‐Azomethine Ylides
Authors: Husinec Suren , Savic Vladimir
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
Activation of Allyl Alcohols as Allyl Cations, Allyl Anions, and Amphiphilic Allylic Species by Palladium
Authors: Tamaru Yoshinao
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
Organic Chemistry of Subvalent Transition Metal Complexes. Part 33. The Decomposition of Transition Metal Alkyls Revisited: Surprising Wellspring of Novel Reagents for Organic Synthesis
Authors: Eisch John J. , Adeosun Adetenu A. , Dutta Somnath , Fregene Paul O.
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
Recent Advances in Transition Metal Catalyzed Oxidation of Organic Substrates with Molecular Oxygen
Authors: Punniyamurthy T. , Velusamy Subbarayan , Iqbal Javed
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
Bioinorganic Photochemistry: Frontiers and Mechanisms
Authors: Szacilowski Konrad , Macyk Wojciech , Drzewiecka‐Matuszek Agnieszka , Brindell Malgorzata , Stochel Grazyna
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
Chemistry of Squaraine‐Derived Materials: Near‐IR Dyes, Low Band Gap Systems, and Cation Sensors
Authors: Ajayaghosh Ayyappanpillai
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
Advances in Singlet Oxygen Chemistry
Authors: Clennan Edward L. , Pace Andrea
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
Photocontrolling Peptide α Helices
Authors: Woolley G. Andrew
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
CH/π Hydrogen Bonds in Organic Reactions
Authors: Nishio M.
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
Rolf Huisgen: Some Highlights of His Contributions to Organic Chemistry
Authors: Ruechardt Christoph , Sauer Juergen , Sustmann Reiner
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
Catalytic Decomposition of Diazo Compounds as a Method for Generating Carbonyl‐Ylide Dipoles
Authors: Padwa Albert
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
Ionic Liquids with Fluorine‐Containing Cations
Authors: Xue Hong , Shreeve Jean'ne M.
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
Transition Metal Catalyzed ortho‐Functionalization in Organic Synthesis
Authors: Park Young Jun , Jun Chul‐Ho
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
The Latest Achievements in Thienothiophene Chemistry
Authors: Litvinov V. P.
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
Interlocked Molecules Containing Quaternary Azaaromatic Moieties
Authors: Sliwa Wanda , Zujewska Teresa
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
Recent Advances in Macrosphelide Synthesis
Authors: Matsuya Yuji , Nemoto Hideo
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
Development of Agonists/Antagonists for Protease‐Activated Receptors (PARs) and the Possible Therapeutic Application to Gastrointestinal Diseases
Authors: Sekiguchi Fumiko
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
p53 Activation by Small Molecules: Application in Oncology
Authors: Vassilev Lyubomir T.
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
Metallodendritic Catalysis: An Efficient Contribution to Green Chemistry
Authors: Astruc Didier
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
Synthesis of Single‐ and Multiple‐Stranded Cystine‐Rich Peptides
Authors: Moroder Luis , Musiol Hans‐Juergen , Goetz Marion , Renner Christian
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
Preparation of 1‐Azide Sugars
Authors: Hayashi Masahiko , Kawabata Hirotoshi
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
Hydrosilylations of Carbonyl and Imine Compounds
Authors: Nishiyama Hisao
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
Olefin Metathesis Directed to Organic Synthesis: Principles and Applications
Authors: Schmidt Bernd , Hermanns Jolanda
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
The Multifaceted Chemistry of Variously Substituted α,β‐Unsaturated Fischer Metal Carbenes
Authors: Wu Yao‐Ting , de Meijere Armin
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
Electronic Structure and Reactivity of Metal Carbenes
Authors: Strassner Thomas
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
Molecular Motors: Synthetic DNA‐Based Walkers Inspired by Kinesin
Authors: Kelly T. Ross
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
Strategies for Targeting Protein—Protein Interactions with Synthetic Agents
Authors: Yin Hang , Hamilton Andrew D.
Published: September 2005

For Abstract see ChemInform Abstract in Full Text.
Nicastrin controls aspects of photoreceptor neuron specification and differentiation in the Drosophila eye
Authors: Zhang Tianyi , Tran Susan , Clouser Christopher , Pignoni Francesca
Published: September 2005

Nicastrin is a component of the Notch signaling pathway involved in proteolytic release of the Notch receptor intracellular domain. It has been postulated that intracellular Notch is required within the nucleus of fly eye progenitor cells to enhance (proneural enhancement) and then repress (lateral inhibition) transcription of proneural genes. We present here an analysis of Nicastrin function during eye development and find that Nicastrin is essential to early photoreceptor neuron development. Nicastrin mutant tissue displays neuronal loss or hyperplasia; these phenotypes can be rescued by targeted expression of an intracellular form of Notch. Thus, nuclear translocation of Notch and its direct regulation of gene expression appear to be critical to proneural enhancement as well as lateral inhibition. In addition, we show that Nicastrin as well as Notch are required to maintain normal R‐cell morphology, because the nuclei of mutant photoreceptor neurons cannot maintain their proper position. Thus, Notch signaling plays a role, not only in cell fate specification, but also in differentiation of photoreceptor neurons. Developmental Dynamics 234:590–601, 2005. © 2005 Wiley‐Liss, Inc.
The basic helix‐loop‐helix factor Hand2 regulates autonomic nervous system development
Authors: Morikawa Yuka , Dai Yan‐Shan , Hao Jianming , Bonin Christopher , Hwang Sunny , Cserjesi Peter
Published: September 2005

Mammalian autonomic nervous system (ANS) development requires the combinatorial action of a number of transcription factors, which include Mash1, Phox2b, and GATA3. Here we show that the bHLH transcription factor, Hand2 (dHAND), is expressed concurrently with Mash1 during sympathetic nervous system (SNS) development and that the expression of Hand2 is not dependent on Mash1. This suggests that these two bHLH factors work in parallel during SNS development. We also show that ectopic expression of Hand2 activates the neuronal program and promotes the acquisition of a phenotype corresponding to peripheral neurons including neurons of the SNS lineage in P19 embryonic carcinoma cells. We propose that Hand2 works in parallel with other members of the transcriptional network to regulate ANS developmental but can ectopically activate the program by a cross‐regulatory mechanism that includes the activation of Mash1. We show that this function is dependent on its interaction with the histone acetyltransferase p300/CBP, indicating that Hand2 functions to promote ANS development as part of a larger transcriptional complex. Developmental Dynamics 234:613–621, 2005. © 2005 Wiley‐Liss, Inc.
Short‐term lineage analysis of dorsally derived Olig3 cells in the developing spinal cord
Authors: Ding Lei , Takebayashi Hirohide , Watanabe Keisuke , Ohtsuki Toshiaki , Tanaka Kenji F. , Nabeshima Yo‐ichi , Chisaka Osamu , Ikenaka Kazuhiro , Ono Katsuhiko
Published: September 2005

We examined the migration and differentiation of cells expressing Olig3, a basic helix‐loop‐helix transcriptional factor, in the developing spinal cord. Distribution of Olig3 lineage cells was demonstrated with in situ hybridization and X‐gal staining in an Olig3‐lacZ knock‐in mouse. Olig3‐positive cells first appeared in the dorsal spinal cord, except for the roof plate. Some of the dorsal Olig3 lineage cells co‐expressed Islet1/2, Math1, or Brn3a, markers for dorsal interneuron. LacZ‐positive cells were observed in the ventral‐most part of the E10.5 spinal cord, suggesting that some dorsal Olig3 lineage cells migrate into the ventral‐most part by E10.5. Ventral‐ward migration of dorsal cells and contribution to commissural interneurons were substantiated by electroporation of EGFP expression plasmid in the dorsal spinal cord of chick embryo. Dorsal midline cells were also LacZ‐positive during development. These findings suggest that dorsal Olig3 cells contribute to dorsal midline cells and commissural interneurons at intermediate and ventral levels. Developmental Dynamics 234:622–632, 2005. © 2005 Wiley‐Liss, Inc.
Differential expression of regulator of G‐protein signaling R12 subfamily members during mouse development
Authors: Martin‐McCaffrey Luke , Hains Melinda D. , Pritchard Grant A. , Pajak Agnieszka , Dagnino Lina , Siderovski David P. , D'Souza Sudhir J.A.
Published: September 2005

Regulators of G‐protein Signaling (RGS proteins) are a multigene family of GTPase‐accelerating proteins for the Gα subunit of heterotrimeric G‐proteins. The mammalian R12 RGS protein subfamily is composed of RGS12 and RGS14, two proteins characterized by their multidomain architecture of hallmark RGS domain, tandem Ras‐binding domains (RBDs), and a second Gα interacting domain, the GoLoco motif. The Rgs12 gene generates multiple splice variants, the largest of which encodes N‐terminal PDZ and PTB domains in addition to the core RGS/RBD/GoLoco motifs. The Rgs14 gene encodes a protein similar to the non‐PDZ/PTB domain RGS12 splice variants. The spatiotemporal expression patterns of RGS12 and RGS14 proteins were examined by immunohistochemistry in a developmental series of postimplantation mouse embryo. We report that RGS12 splice variants exhibit differential spatiotemporal patterns of expression during postimplantation embryogenesis, suggesting nonoverlapping roles. In contrast, RGS14 is found ubiquitously throughout the postimplantation period. We conclude that R12 subfamily RGS proteins likely play significant and different roles in specific tissues and periods of mouse embryogenesis. Developmental Dynamics 234:438–444, 2005. © 2005 Wiley‐Liss, Inc.
Monocilia on chicken embryonic endocardium in low shear stress areas
Authors: Van der Heiden Kim , Groenendijk Bianca C.W. , Hierck Beerend P. , Hogers Bianca , Koerten Henk K. , Mommaas A. Mieke , Gittenberger‐de Groot Adriana C. , Poelmann Robert E.
Published: September 2005

During cardiovascular development, fluid shear stress patterns change dramatically due to extensive remodeling. This biomechanical force has been shown to drive gene expression in endothelial cells and, consequently, is considered to play a role in cardiovascular development. The mechanism by which endothelial cells sense shear stress is still unidentified. In this study, we postulate that primary cilia function as fluid shear stress sensors of endothelial cells. Such a function already has been attributed to primary cilia on epithelial cells of the adult kidney and of Hensen's node in the embryo where they transduce mechanical signals into an intracellular Ca2+ signaling response. Recently, primary cilia were observed on human umbilical vein endothelial cells. These primary cilia disassembled when subjected to high shear stress levels. Whereas endocardial–endothelial cells have been reported to be more shear responsive than endothelial cells, cilia are not detected, thus far, on endocardial cells. In the present study, we use field emission scanning electron microscopy to show shear stress‐related regional differences in cell protrusions within the cardiovasculature of the developing chicken. Furthermore, we identify one of these cell protrusions as a monocilium with monoclonal antibodies against acetylated and detyrosinated alpha‐tubulin. The distribution pattern of the monocilia was compared to the chicken embryonic expression pattern of the high shear stress marker Krüppel‐like factor‐2. We demonstrate the presence of monocilia on endocardial–endothelial cells in areas of low shear stress and postulate that they are immotile primary cilia, which function as fluid shear stress sensors. Developmental Dynamics 235:19–28, 2006. © 2005 Wiley‐Liss, Inc.
Message in a bottle: Role of the 70‐kDa heat shock protein family in anti‐tumor immunity
Authors: Calderwood Stuart K. , Theriault Jimmy R. , Gong Jianlin
Published: September 2005

Extracellular heat shock protein 70 (HSP70) is a potent agent for tumor immunotherapy, which can break tolerance to tumor‐associated antigens and cause specific tumor cell killing by cytotoxic CD8+ T cells. The pro‐immune effects of extracellular HSP70 are, to some extent, extensions of its molecular properties as an intracellular stress protein. The HSP70 are characterized by massive inducibility after stress, preventing cell death by inhibiting aggregation of cell proteins and directly antagonizing multiple cell death pathways. HSP70 family members possess a domain in the C terminus that chaperones unfolded proteins and peptides, and a N‐terminal ATPase domain that controls the opening and closing of the peptide binding domain. These properties not only enable intracellular HSP70 to inhibit tumor apoptosis, but also promote formation of stable complexes with cytoplasmic tumor antigens that can then escape intact from dying cells to interact with antigen‐processing cells (APC) and stimulate anti‐tumor immunity. HSP70 may be released from tumors undergoing therapy at high local extracellular concentrations, and send a danger signal to the host leading to APC activation. Extracellular HSP70 bind to high‐affinity receptors on APC, leading to activation of maturation and re‐presentation of the peptide antigen cargo of HSP70 by the APC. The ability of HSP70‐peptide complexes (HSP70‐PC) to break tolerance and cause tumor regression employs these dual properties as signaling ligand and antigen transporter. HSP70‐PC thus coordinately activate innate immune responses and deliver antigens for re‐presentation by MHC class I and II molecules on the APC cell surface, leading to specific anti‐tumor immunity.
Vaccine route, dose and type of delivery vector determine patterns of primary CD8+ T cell responses
Authors: Estcourt Marie J. , Létourneau Sven , McMichael Andrew J. , Hanke Tomáš
Published: September 2005

The dynamics of primary CD8+ T cell responses following administration of modified virus Ankara (MVA)‐ and DNA‐vectored vaccines was investigated in a mouse model. To overcome the low frequency of naive antigen‐specific precursors and follow the early expansion events, naive CFSE‐labelled T cell receptor‐transgenic F5 lymphocytes were transferred into syngeneic non‐transgenic recipients prior to vaccination. Using the i.d., i.v. and i.m. routes and increasing recombinant MVA (rMVA) vaccine doses, the primary response was analysed on a divisional basis at local and distant lymphoid organs at various times after vaccination. The results indicated that F5 cell divisions were initiated in the local draining lymph nodes and cells only after five to six divisions appeared at more distant sites. The rMVA dose affected frequencies of cells entering division and at the peak response. When priming induced by rMVA and plasmid DNA was compared, dramatic differences in the cycling patterns were observed with plasmid DNA inducing a response slower and more sustained over the first 2 wk than rMVA. Both rMVA and DNA induced comparable IFN‐γ production, which increased with cell divisions. Taken together, the vaccine type, dose and route have a strong influence on the spatial and temporal patterns of initial T cell responses.

See accompanying commentary http://dx.doi.org/10.1002/eji.200535335
Bench‐scale evaluation of advanced oxidation processes for treatment of a cyanide‐contaminated wastewater from an engine manufacturing facility
Authors: Ford Jack , Hernandez Rafael , Zappi Mark
Published: September 2005

Advanced oxidation processes (AOPs) are aggressive chemical oxidation techniques that are characterized by the formation of hydroxyl radicals. This treatability study evaluated the performance of the following AOPs for treating cyanide‐contaminated wastewater from an engine manufacturing company: low‐pressure ultraviolet (LPUV) light/ozone (O3), medium‐pressure UV (MPUV)/hydrogen peroxide (H2O2), MPUV/O3/H2O2, and peroxone (combination of O3 and H2O2). A bench‐scale reactor was used to examine the relative effectiveness of each AOP for removal of both cyanide and total organic carbon (TOC) from the wastewater. Initial cyanide concentration of the water was 0.6 mg/L. The experiments were run for 1 h. The LPUV/O3 process removed 18 and 60% of the initial cyanide and TOC in the wastewater, respectively. The changes in TOC observed with the evaluated peroxone schemes (5% O3/100 mg/L H2O2 and 1% O3/100 mg/L H2O2) were almost identical to those seen with the LPUV/O3 system. The combination of medium‐pressure UV and 500 mg/L H2O2 performed best among the AOPs in the study with respect to cyanide removal. Surprisingly low removal of TOC was observed, indicating a low potential for hydroxyl radicals to remove the organic fraction from this wastewater. A combination of all the results indicates that the main mechanisms of TOC and cyanide removal are volatilization and photolysis, respectively. The results of the treatability study were used in designing a water treatment system currently in operation at the engine manufacturing facility. © 2005 American Institute of Chemical Engineers Environ Prog, 2005
The order of genetic events associated with colorectal cancer progression inferred from meta‐analysis of copy number changes
Authors: Diep Chieu B. , Kleivi Kristine , Ribeiro Franclim R. , Teixeira Manuel R. , Lindgjærde Ole C. , Lothe Ragnhild A.
Published: September 2005

To identify chromosomal aberrations that differentiate among the Dukes' stages of colorectal cancer (CRC) as well as those that are responsible for the progression into liver metastases, we performed a meta‐analysis of data obtained from 31 comparative genomic hybridization (CGH) studies comprising a total of 859 CRCs. Individual copy number profiles for 373 primary tumors and 102 liver metastases were recorded and several statistical analyses, such as frequency, multivariate logistic regression, and trend tests, were performed. In addition, time of occurrence analysis was applied for the first time to copy number changes identified by CGH, and each genomic imbalance was thereby classified as an early or late event in colorectal tumorigenesis. By combining data from the different statistical tests, we present a novel genetic pathway for CRC progression that distinguishes the Dukes' stages and identifies early and late events in both primary carcinomas and liver metastases. Results from the combined analyses suggest that losses at 17p and 18 and gains of 8q, 13q, and 20 occur early in the establishment of primary CRCs, whereas loss of 4p is associated with the transition from Dukes' A to B–D. Deletion of 8p and gains of 7p and 17q are correlated with the transition from primary tumor to liver metastasis, whereas losses of 14q and gains of 1q, 11, 12p, and 19 are late events. We supplement these findings with a list of potential target genes for the specific alterations from a publicly available microarray expression dataset of CRC. This article contains Supplementary Material available at http://www.interscience.wiley.com/jpages/1045‐2257/suppmat. © 2005 Wiley‐Liss, Inc.
Self‐motion and the origin of differential spatial scaling along the septo‐temporal axis of the hippocampus
Authors: Maurer Andrew P. , VanRhoads Shea R. , Sutherland Gary R. , Lipa Peter , McNaughton Bruce L.
Published: September 2005

Spatial scaling of place specific activity in the hippocampus varies systematically from the septal pole (high resolution) to the temporal pole (low resolution). Place fields get progressively larger, and the probability of observing a field in a given environment gets progressively smaller. It was previously found that decoupling movement in space from ambulation, by having the animal actively ride on a mobile platform, results in marked enlargement of the spatial scale factor in the dorsal hippocampus and a reduction in the increase in theta rhythm power with running speed, suggesting that a self‐motion signal determines the spatial scale at which the hippocampal population vector updates. These results led to the hypothesis that the gain of the self‐motion signal may vary systematically along the septo‐temporal axis of the hippocampus. To test this hypothesis, EEG theta rhythm and ensembles of CA1 pyramidal cells and interneurons were recorded from the extreme dorsal and middle portions of the hippocampus. Pyramidal cell population vectors representing successive locations became decorrelated over substantially shorter distances in the dorsal than in the middle hippocampus. Dorsal pyramidal cells had smaller place fields, higher mean and peak firing rates, and higher intrinsic oscillation frequencies during track running than that of middle pyramidal cells. Both dorsal pyramidal cells and interneurons had more elevated mean rates during running, compared with rest, than that of the corresponding cell classes in the middle hippocampus, and both cell classes increased their rates more as a function of speed in the dorsal hippocampus.

The amplitude, but not the frequency of fissure recorded theta rhythm, increased more as a function of running speed in the dorsal than in the middle hippocampus. We conclude that variation in the neuronal response to movement speed is the likely basis for the systematic variation in spatial scaling along the septo‐temporal axis of the hippocampus. © 2005 Wiley‐Liss, Inc.
Dual phase and rate coding in hippocampal place cells: Theoretical significance and relationship to entorhinal grid cells
Authors: O'Keefe John , Burgess Neil
Published: September 2005

We review the ideas and data behind the hypothesis that hippocampal pyramidal cells encode information by their phase of firing relative to the theta rhythm of the EEG. Particular focus is given to the further hypothesis that variations in firing rate can encode information independently from that encoded by firing phase. We discuss possible explanation of the phase‐precession effect in terms of interference between two independent oscillatory influences on the pyramidal cell membrane potential, and the extent to which firing phase reflects internal dynamics or external (environmental) variables. Finally, we propose a model of the firing of the recently discovered “grid cells” in entorhinal cortex as part of a path‐integration system, in combination with place cells and head‐direction cells. © 2005 Wiley‐Liss, Inc.
The influence of prematurity, maternal anxiety, and infants' neurobiological risk on mother–infant interactions
Authors: Schmücker Gesine , Brisch Karl‐Heinz , Köhntop Brigitte , Betzler Susanne , Österle Margret , Pohlandt Frank , Pokorny Dan , Laucht Manfred , Kächele Horst , Buchheim Anna
Published: September 2005

In this study, we investigated how the birth of a very low birth weight preterm (VLBW) infant influences the mother–infant interaction at 3 months. We also focused on the impact of the infant's neurobiological risk and maternal anxiety, and their interaction. The comparison of the VLBW preterm sample (n = 79) with an external full‐term sample (n = 35) showed mother–infant interactions of the families with the preterm infant to be more vocally responsive during the interaction, but less facially responsive during the interaction. Additionally, higher levels of maternal anxiety were associated with preterm infants being less facially responsive in interaction with their mother. While neurobiological risk of the infant played a part in this association, with higher risk infants also being less facially responsive, the relationship with maternal anxiety and the mother–child interaction was stronger. How these findings may influence therapeutic interventions is discussed.
Application of torsion angle molecular dynamics for efficient sampling of protein conformations
Authors: Chen Jianhan , Im Wonpil , Brooks Charles L.
Published: September 2005

We investigate the application of torsion angle molecular dynamics (TAMD) to augment conformational sampling of peptides and proteins. Interesting conformational changes in proteins mainly involve torsional degrees of freedom. Carrying out molecular dynamics in torsion space does not only explicitly sample the most relevant degrees of freedom, but also allows larger integration time steps with elimination of the bond and angle degrees of freedom. However, the covalent geometry needs to be fixed during internal coordinate dynamics, which can introduce severe distortions to the underlying potential surface in the extensively parameterized modern Cartesian‐based protein force fields. A “projection” approach (Katritch et al. J Comput Chem 2003, 24, 254–265) is extended to construct an accurate internal coordinate force field (ICFF) from a source Cartesian force field. Torsion crossterm corrections constructed from local molecular fragments, together with softened van der Waals and electrostatic interactions, are used to recover the potential surface and incorporate implicit bond and angle flexibility. MD simulations of dipeptide models demonstrate that full flexibility in both the backbone ϕ/ψ and side chain χ1 angles are virtually restored. The efficacy of TAMD in enhancing conformational sampling is then further examined by folding simulations of small peptides and refinement experiments of protein NMR structures. The results show that an increase of several fold in conformational sampling efficiency can be reliably achieved. The current study also reveals some complicated intrinsic properties of internal coordinate dynamics, beyond energy conservation, that can limit the maximum size of the integration time step and thus the achievable gain in sampling efficiency. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 1565–1578, 2005
Calculation of rotational partition functions by an efficient Monte Carlo importance sampling technique
Authors: Tafipolsky M. , Schmid R.
Published: September 2005

The evaluation of the classical rotational partition function represented by a configuration integral over all external and internal rotational degrees of freedom of nonrigid chain polyatomic molecules is described. The method of Pitzer and Gwinn is used to correct the classical partition function for quantum mechanical effects at low temperatures. The internal rotor hindrance and all coupling arising from the external and internal rotational degrees of freedom are explicitly taken into account. Importance sampling Monte Carlo based on the adaptive VEGAS algorithm to perform multidimensional integration is implemented within the TINKER program package. A multidimensional potential energy hypersurface is calculated with the MM3(2000) molecular mechanics force field. Numerical tests are performed on a number of small n‐alkanes (from ethane to octane), for which the absolute entropies calculated at three different temperatures are compared both with the experimental values and with the previous theoretical results. The application of a more efficient importance sampling technique developed here results in a substantial reduction of statistical errors in the evaluation of the configuration integral for a given number of Monte Carlo steps. Error estimates for the calculated entropies are given, and possible sources of systematic errors, and their importance for a reliable prediction of the absolute entropy, are discussed. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 1579–1591, 2005
A comparison of the cholinesterases of an oyster (Crassostrea virginica) and a clam (Macrocallista nimbosa)
Authors: Roop Tom , Greenberg Michael J.
Published: September 2005

Cholinesterase activities in the hearts and ganglia of an oyster (Crassostrea virginica) and a venerid clam (Macrocallista nimbosa) were measured and compared. Tissue extracts were partially purified by ammonium sulfate fractionation followed by gel column chromatography. Enzymatic activity was assayed spectrophotometrically; substrates were acetyl‐, butyryl‐, and propionylthiocholine (ATC, BTC, PTC). Kinetic constants characterizing each enzyme were derived. At all substrate concentrations, the hydrolysis rates of both clam enzymes were in the order: BTC > PTC > ATC. With oyster enzymes the ranking was ATC ≥ PTC > BTC. The specific activities of oyster heart and ganglion enzymes were similar. In contrast, clam ganglion extracts were 75–100 times more active than clam heart extracts and, with any substrate, had greater activity than either oyster enzyme. All enzyme preparations proved to be homogeneous on the bases of constant substrate activity ratios in successive column fractions, and of intermediate velocities with mixed substrates. Six cholinesterase inhibitors were tested. The specific acetylcholinesterase antagonist, B.W. 62c47, was much more effective against oyster enzymes, while the specific antibutylcholinesterase, iso‐OMPA, almost totally inhibited clam enzyme activity, but had little effect on oyster. Eserine was the most effective inhibitor of both enzymes. In conclusion, the enzymes in oyster tissues are acetylcholinesterases, while clam enzymes are butyrylcholinesterases. Nevertheless, clam ganglion esterase is sifficiently active to hydrolyze the physiological substrate, acetyl‐choline. These results explain the long‐observed differences in isolated heart pharmacology between ostreid and venerid bivalves.
Thermosensitivity of pattern formation in a ciliate Chilodonella cucullulus
Authors: Kaczanowska Janina , Kiersnowska Mauryla
Published: September 2005

During divisional morphogenesis of the ciliate protozoan Chilodonella cucullulus different thermosensitivity is observed at early and advanced stages of development.

Thermic shocks (of 31 or 32°C) applied to cells early in division bring about resorption of new developing cortical organelles, while the same shocks do not prevent further development and cell division if applied to advanced dividers. Thus as in many other cells a transition point in thermosensitivity occurs during the cell cycle.

The period before the transition point corresponds to primary pattern formation of primordia of new cortical organelles, the post transitional period corresponds to final pattern formation of sets of organelles for offspring. In control (unheated) cells some simultaneous processes of differentiation and dedifferentiation are observed both in the pre‐transitional and post‐transitional periods. Therefore the stability of development at high temperature which is attained in the post‐transitional period concerns specific selection of organelles for further development rather than over‐all stability of formed structures.

The effect of preincubation at low temperature and at mild temperature on thermosensitivity at 31°C is compared. Cells preincubated at low temperature can go through one round of divisional morphogenesis, while those preincubated at mild temperature are not able to do this; instead they regress into a resorption stage. Cells preincubated at low temperature and shifted to high temperature also sometimes manifest abnormalities in the number and disposition of contractile vacuole pores (CVPs). Hence in these cells thermosensitivity of pattern formation is demonstrated.
Hypoxia: A succinate‐fumarate electron shuttle between peripheral cells and lung
Authors: Cascarano Joseph , Ades Ibrahim Z. , O'Connor John D.
Published: September 2005

The objective of this investigation was to determine if the succinate that accumulates in anoxic or hypoxic tissues of mammals is (a) increased in concentration in the blood, (b) excreted in the urine or (c) recycled in some manner. Rats were subjected to 0.4 atm and the plasma analyzed for succinate and fumarate at 2 hours, 24 hours and 28 days. Significant increases of succinate or succinate plus fumarate were obtained at 2 hours and at 28 days at 0.4 atm. Analysis of 24‐hour samples of urine obtained from controls and animals at 0.4 atm for 28 days demonstrated that no substantial increase in succinate excretion occurred with acclimation. Lung slices were incubated in Krebs‐Ringer bicarbonate and succinate and gassed with O2:CO2 (95:5). Such oxygenated lung slices not only utilized succinate but produced a comparable quantity of fumarate plus malate. It is concluded that succinate produced from fumarate and α‐ketoglutarate in peripheral hypoxic tissue is transported by the blood to the oxygenated lungs. There it is oxidized to fumarate and recycled as fumarate and malate to the periphery. In this way metabolites can act as electron shuttles between peripheral cells and lung.
Breakdown of the germinal vesicle in pig oocytes in vivo and in vitro
Authors: Motlík Jan , Fulka Josef
Published: September 2005

The breakdown of the pig germinal vesicle (GV) was studied in follicular oocytes matured in vivo and in vitro. For better characterization, the whole process was divided into four well‐defined stages, based on the chromatin changes, and on nucleolus and nuclear membrane disappearance. In the intact germinal vesicle (GV I) nuclear membrane and nucleolus are clearly visible and chromatin forms a ring or horseshoe around the nucleolus. In the GV II a few orceinpositive structures (chromocenters) on the nuclear membrane can be detected. For the GV III slightly stained chromatin clumps, localized especially around the nucleolus, and the beginning of strand formation are typical. In the last stage ‐ GV IV ‐ the nuclear membrane is less distinct and the nucleolus disappears completely. Chromatin is seen as an irregular network or as individual bivalents. According to these criteria GV breakdown in vivo was completed in most oocytes between 20 to 24 hours after HCG injection. In culture a similar stage of development was reached between 16 to 20 hours. This difference in the progress of nuclear changes appeared at the beginning of nuclear maturation and remained unchanged throughout the whole period studied.
Morphology and kinetics of the hamster sperm acrosome reaction
Authors: Talbot Prudence , Franklin L. E.
Published: September 2005

The morphology and kinetics of the normal acrosome reaction were examined in vitro using hamster sperm incubated in detoxified sera. The reaction involved either swelling and elevation or crenulation and fragmentation of the acrosomal cap. Swelling and elevation occurred during both normal and degenerative reactions, as reported by others. Crenulation with subsequent fragmentation of the cap was observed during normal reactions. Early crenulation of the acrosome could be induced by cold shock (5°C, 25 minutes), but this did not decrease the incubation time required (at 37°C) for completion of the normal reaction. In appropriate sera, the occurrence of normal and degenerative acrosome reactions in motile sperm was significantly separated in time to study the reactions independently. The duration of the normal reaction, i.e., the time between the first morphological change in the acrosome (initiation) until the actual detachment of the cap (termination) was estimated to be 20 minutes. Saline dilution of these sera delayed initiation of the reaction and increased the duration of the reaction once it had started. Data from cold‐shock and serum dilution experiments indicate that the mechanisms which govern the initiation and termination of the normal reaction are independently variable, and further suggest that initiation involves a change in membrane permeability and that termination includes membrane vesiculation.
The development of the oxygen permeability of the avian egg shell and its membranes during incubation
Authors: Lomholt Jens Peter
Published: September 2005

The O2‐permeability of the avian egg shell and shell membranes is initially low (≅0.1·10−6 ml O2 STP‐sec−1·cm−2mmHg−1) during incubation but increases about 10‐fold after the first week. This increase correlates with a decline in water content of the membranes. A major increase in colloid osmotic pressure (up to 50 cm Hg) occurs and is the suggested cause for the onset of rapid removal of water from the membranes. A high membrane water content correlates with low O2‐permeability and vice versa. The final degree of membrane hydration reached during incubation is independent of ambient humidity; that is, the O2‐permeability of the shell and its membranes is controlled by conditions inside the egg. An hypothesis is presented to explain the profound increase in O2‐permeability while the rate of water loss from the egg remains stable during incubation. The removal of water from the shell membranes by the increased colloid osmotic pressure will increase the number of gas filled channels in the membranes which in turn will increase the O2‐permeability. In spite of the change in water content, the water vapor pressure in the shell membranes will always be very close to that of a free water surface and water loss will hence be determined by the ambient humidity and the porosity of the mineral shell.
Epithelial stratification in the developing chick cornea
Authors: Nuttall Robert P.
Published: September 2005

The process of epithelial stratification was studied in the embryonic chick corneal epithelium between 10 and 21 days of incubation. Information was collected on the DNA synthetic activity occurring in individual cell layers, on cell density changes in the basal layer, and on mitotic spindle orientation in each cell layer before, during, and upon the completion of layer formation.

Prior to the initiation of stratification, mitotic spindles are oriented parallel to the basement membrane interface. This orientation changes to predominantly vertically directed spindles as layer formation proceeds. Later, the majority of the spindles are horizontally aligned once more. This pattern was observed as each successive cell layer formed. The possible relationship between the spindle data and that obtained on DNA synthetic activity and cell density changes is discussed in terms of the role these factors might play in layer formation in the cornea, as well as in other stratified epithelia.
Evidence for the presence of nasal salt glands in the roadrunner and the Coturnix quail
Authors: Dunson William A. , Dunson Margaret K. , Ohmart Robert D.
Published: September 2005

The purpose of this investigation was to determine whether or not the nasal glands of the roadrunner and the Coturnix quail show cytological specializations for salt secretion. In addition, the Na‐K ATPase content of the quail gland was determined before and after drinking of saline solutions, in an effort to evaluate the functional status of the gland. The ability to maintain weight while drinking salt water was also measured as a general index of tolerance to saline conditions. The ultrastructure of the nasal glands of the roadrunner injected with salt and of quail drinking 200 mM NaCl was similar to that of salt glands in reptiles and the fresh‐water acclimated duck. Numerous lateral cell evaginations and abundant mitochondria were present in the principal cell types. There was a significant increase in quail nasal gland Na‐K ATPase when young birds were offered only saline solutions to drink. The ability of Coturnix quail to maintain weight while drinking saline solutions improves with age and at adulthood is comparable to that of some North American desert quail. Roadrunners were previously known to possess functional salt glands whereas quail were not. However the characteristic fine structure and the high Na‐K ATPase content of the quail nasal gland suggest that it is a salt gland.
Cytophotometric study of nuclear proteins during embryogenesis in two nematode species, Ascaris lumbricoides and Panagrellus silusiae
Authors: Pasternak J. , Barrell R.
Published: September 2005

Patterns of nuclear protein changes during embryogenesis in two nematode systems: Ascaris lumbricoides and Panagrellus silusiae were examined microspectrophotometrically. In both species, development is accompanied by an extensive loss of basic nuclear protein as noted by the diminished intranuclear binding of both the Sakaguchi reagent and fluorodinitrobenzene chromophore. The alkaline fast green (pH 8.1) procedure stained both nuclear and cytoplasmic regions of interphase cells to a similar extent throughout embryogenesis. In cells at metaphase the chromosomes bound the fast green dye intensely while the cytoplasm continued to give a positive reaction. Relative Feulgen stainability of nuclei during embryonic development varied between species. In Ascaris, the one‐celled stage nucleus was Feulgen‐negative and the LI juvenile somatic nuclei yielded a mean Feulgen‐DNA value which was considerably less than a postdiminution diploid DNA equivalent. In Panagrellus, the nuclei of one‐celled stage embryos contain DNA in excess of a 4C quantity which subsequently is reduced during embryonic divisions. As in Ascaris the nuclei of Panagrellus, LI juveniles give hypodiploid Feulgen‐DNA values. The significance of these changes remains to be determined.
Cytophotometric analysis of basic nuclear proteins during gametogenesis in the free‐living nematode Panagrellus silusiae
Authors: Pasternak J. , Barrell R.
Published: September 2005

The cytochemical staining characteristics of basic nuclear proteins during gametogenesis in both sexes of the free‐living nematode Panagrellus silusiae were monitored by absorption microspectrophotometry. During spermatogenesis, the levels of both of the nuclear‐bound Sakaguchi and 1‐fluoro‐2, 4‐dinitrobenzene (FDNB) reagents per Feulgen‐DNA content increase prior to meiosis and subsequently drop off during spermiogenesis. During oogenesis, the amount of Sakaguchi‐protein to DNA ratio rises slightly whereas the FDNB‐protein to DNA ratio undergoes a meagre decline. Since the oocyte of Panagrellus accumulates DNA in excess of a 4C DNA equivalent, the relative constancy of the ratio of basic nuclear protein content to DNA amount during oogenesis signifies that these proteins are being continuously produced during oocyte maturation. After treatment with alkaline fast green (pH 8.1) the cytoplasmic and nuclear regions of the gonocytes of both sexes yield such an intense reaction that microspectrophotometric measurements could not be taken. The basis of the cytoplasmic staining reaction to the fast green (pH 8.1) dye was not determined. The rapid, highly deterministic programme of embryogenesis in Panagrellus may require a substantial stockpiling of basic nuclear proteins duing oogenesis.
Testis specific phosphoglycerate kinase B in mouse
Authors: Vandeberg J. L. , Cooper D. W. , Close P. J.
Published: September 2005

Mammals possess two genetically distinct forms of phosphoglycerate kinase (PGK). Only the X‐linked PGK‐A isozyme is detectable by electrophoresis of somatic and ovarian tissues of the mouse and of most other eutherian mammals studied to date. The PGK‐B isozyme is highly active in testes and epididymides which contain spermatozoa, as well as in semen. PGK‐B activity is first detectable in testes of 22‐day‐old mice and shows rapid increase concomitant with germ cell proliferation until day 40, after which activity increases only slightly. Two allelic isozymes (F and S) in mice express equal enzyme activity and are inherited in an autosomal codominant manner. One is equally as heat stable as PGK‐A; the other is heat labile. Two of the 33 strains tested express neither F nor S, but do express a faintly staining PGK band which is of slightly faster mobility than F and which is absent from the other stains. This may represent a third allelic isozyme of PGK‐B with reduced enzyme activity.
X‐ray induced inhibition of DNA synthesis and mitosis in internal tissues during the initiation of limb regeneration in the adult newt
Authors: Wertz Richard L. , Donaldson Donald J. , Mason James M.
Published: September 2005

Left front limbs of adult male newts were given 2000r of X‐irradiation at least four weeks prior to amputation of both forelimbs. Internal stump tissues were evaluated for the ability to incorporate 3H‐thymidine and accumulate colchicine‐blocked mitotic figures. In otherwise uninjured limbs, irradiation stimulated low levels of DNA synthesis which did not increase significantly after amputation. Thus, as soon as DNA synthesis increased significantly in normal limbs as a result of amputation, it was demonstrably higher than in X‐rayed limbs. In general, mitotic activity in both groups reflected the DNA synthetic rates. Since others have shown that denervation at the time of amputation blocks subsequent mitosis in internal stump tissues yet allows normal levels of DNA synthesis for eight days, we conclude that X‐irradiation and denervation prevent cell division in potential blastema cells by different mechanisms.
The role of extracellular material in chick neurulation. I. Effects of concanavalin A
Authors: Lee Hsin‐Yi , Sheffield Joel B. , Nagele Robert G. , Kalmus Gerhard W.
Published: September 2005

The distribution of extracellular material (ECM) in developing neuroepithelium of stage 8+ chick embryos was investigated using lanthanum nitrate. The temporal changes in the distribution of ECM was correlated with the ongoing morphogenetic movements. The most striking finding was that as the folds were about to meet, thick dense ECM appeared between leading edges. Concanavalin A inhibited neural tube closure by binding to cell surfaces and disrupting the usual distribution of ECM in developing neuroepithelium.
Hydration measurements on individual Artemia cysts
Authors: Clegg James S.
Published: September 2005

The water contents of individual cysts of the brine shrimp, Artemia salina, equilibrated at different relative vapor pressures of water, have been measured using tritiated water. These measured hydration levels compared favorably with those calculated from measurements on large populations of cysts using gravimetric methods. Therefore, studies of cyst hydration using large populations can be interpreted in terms of the behavior of individual cysts.