bluuebunny/crossref_metadata_2025 huggingface dataset:
Asymmetric Iodolactamization Induced by Chiral Oxazolidine Auxiliary.
Authors: Shen Meihua , Li Chaozhong
Published: February 2005

For Abstract see ChemInform Abstract in Full Text.
Interaction of Hydroxylamine with Esters of 2‐Oxobutenoic Acids. Synthesis of 3‐Hydroximino‐1‐hydroxy‐2‐pyrrolidinones.
Authors: Katkevics M. , Korchagova E. , Ivanova T. , Slavinska V. , Lukevics E.
Published: February 2005

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A Novel Pyrrole Synthesis.
Authors: Agarwal Sameer , Knoelker Hans‐Joachim
Published: February 2005

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Indole Synthesis by Controlled Carbolithiation of o‐Aminostyrenes.
Authors: Kessler Albane , Coleman Claire M. , Charoenying Patchanee , O'Shea Donal F.
Published: February 2005

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Palladium‐Catalyzed Synthesis of N‐Aryl‐2‐benzylindolines via Tandem Arylation of 2‐Allylaniline: Control of Selectivity Through in situ Catalyst Modification.
Authors: Lira Ricardo , Wolfe John P.
Published: February 2005

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Convenient Synthesis of Pyrrole‐ and Indolecarboxylic Acid tert‐Butylesters.
Authors: Ludwig Joachim , Lehr Matthias
Published: February 2005

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Synthesis of a Number of Sulfoalkanoic and Sulfamido Acids on the Basis of N‐Acylated Indoline Derivatives.
Authors: Shalygina E. E. , Kobylinskii D. V. , Skorenko A. V. , Korikov P. V. , Solov'ev M. Yu. , Balakin K. V. , Dorogov M. V.
Published: February 2005

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Synthesis of Enantiopure Imidazolines Through a Ritter Reaction of 2‐(1‐Aminoalkyl)aziridines with Nitriles.
Authors: Concellon Jose M. , Riego Estela , Suarez Jose Ramon , Garcia‐Granda Santiago , Diaz M. Rosario
Published: February 2005

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Synthesis of Some 2‐[(Benzazole‐2‐yl)thio]‐diphenylmethylacetamide Derivatives and Their Antimicrobial Activity.
Authors: Turan‐Zitouni G. , Kaplancikli Z. A. , Ucucu Ue. , Oezdemir A. , Chevallet P. , Tunali Y.
Published: February 2005

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Efficient Conversion of O‐Substituted 3‐Hydroxy‐4‐imino‐oxazolidin‐2‐ones into O‐Substituted α‐Hydroxyamidoximes.
Authors: Kurz Thomas , Widyan Khalid
Published: February 2005

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Addition of Nitrile Oxides to Aryl Allyl Ethers.
Authors: Alksnis E. , Muravenko V. , Dirnens V. , Lukevics E.
Published: February 2005

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A One‐Pot Synthesis of Alkyl 5‐Amino‐2‐mercaptothiazole‐4‐carboxylates and Sulfur‐Claisen Type Rearrangement Reactions of the Corresponding S‐Allyl/Propargyl Compounds.
Authors: Ray Sibdas , Ghosh Sukla
Published: February 2005

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New Synthetic Approach to Cyclopenta‐Fused Heterocycles Based upon a Mild Nazarov Reaction. Part 2. Further Studies on the Torquoselectivity.
Authors: Prandi Cristina , Ferrali Alessandro , Guarna Antonio , Venturello Paolo , Occhiato Ernesto G.
Published: February 2005

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Synthesis and Cytotoxic Activity of 4‐Substituted 3‐Cyano‐6,6‐dimethyl‐5,6‐dihydro‐2‐pyranones.
Authors: Leite L. , Jansone D. , Fleisher M. , Kazhoka H. , Popelis J. , Veretennikova N. , Shestakova I. , Domracheva I. , Lukevics E.
Published: February 2005

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One‐Pot Synthesis of 12‐Hydroxy‐12H‐benzo[b]thioxanthene‐6,11‐diones from 1,4‐Naphthoquinone and o‐Acylbenzenethiols.
Authors: Kobayashi Kazuhiro , Umakoshi Hironobu , Matsunaga Akihiro , Tanmatsu Miyuki , Morikawa Osamu , Konishi Hisatoshi
Published: February 2005

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Ligand Effects in the Rh(II) Catalyzed Reaction of α‐Diazo Ketoamides.
Authors: Mejia‐Oneto Jose M. , Padwa Albert
Published: February 2005

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Synthesis of Dicyanopyridines.
Authors: Roblou Emmanuel , Sasaki Isabelle , Pezet Frederic , Ait‐Haddou Hassan , Vincendeau Sandrine
Published: February 2005

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Electroreductive Intramolecular Coupling of Aromatic β‐ and γ‐Imino Esters: A New Synthetic Method for N‐Alkoxycarbonyl‐2‐aryl‐3‐ones and cis‐2‐Aryl‐3‐ols of Pyrrolidines and Piperidines.
Authors: Kise Naoki , Ohya Kengo , Arimoto Kie , Yamashita Yutaka , Hirano Yuuki , Ono Tadahiro , Ueda Nasuo
Published: February 2005

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Activation of Pyridinium Salts for Electrophilic Acylation: A Method for Conversion of Pyridines into 3‐Acylpyridines.
Authors: Klapars A. , Vedejs E.
Published: February 2005

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Alkylation of Quinoline and Isoquinoline in the Presence of LiCl.
Authors: Chang Yu Mi , Park Young Sang , Lee Seung Hwan , Yoon Cheol Min
Published: February 2005

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Synthesis of 6‐Phenanthridinones and Their Heterocyclic Analogues Through Palladium‐Catalyzed Sequential Aryl—Aryl and N‐Aryl Coupling.
Authors: Ferraccioli Raffaella , Carenzi Davide , Rombola Ottavio , Catellani Marta
Published: February 2005

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Synthesis of a New Tricyclic 3‐(Tetrazol‐5‐yl)pyridine System from 2‐(Azidomethyl)nicotinonitriles.
Authors: Bliznets Igor V. , Shorshnev Sergey V. , Aleksandrov Grigory G. , Stepanov Aleksandr E. , Lukyanov Sergey M.
Published: February 2005

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Synthesis of Disubstituted Imidazo[4,5‐b]pyridin‐2‐ones.
Authors: Kuethe Jeffrey T. , Wong Audrey , Davies Ian W.
Published: February 2005

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Conversion of 1,3‐Oxathiolanes to 1,4‐Oxathianes Using a Silylated Diazoester.
Authors: Ioannou Maria , Porter Michael J. , Saez Fabienne
Published: February 2005

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A Novel Pyrenophane Bearing Tetraazathiapentalene Skeleton.
Authors: Hayashi Hirokazu , Matsumura Noboru , Mizuno Kazuhiko
Published: February 2005

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Solution‐Phase Parallel Synthesis of an N‐Alkylated Dihydropteridinone Library from Fluorous Amino Acids.
Authors: Nagashima Tadamichi , Zhang Wei
Published: February 2005

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Lewis Acid Promoted Annulation of o‐Quinonediimines by Allylstannane: A Facile Synthesis of Quinoxaline Derivatives.
Authors: Nair Vijay , Dhanya R. , Rajesh C. , Bhadbhade Mohan M. , Manoj K.
Published: February 2005

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Novel Salicylaldehyde‐Based Mineral‐Supported Expeditious Synthesis of Benzoxazin‐2‐ones.
Authors: Yadav Lal Dhar S. , Kapoor Ritu
Published: February 2005

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Ammonium Ion Binding Property of Naphtho‐Crown Ethers Containing Thiazole as Sub‐Cyclic Unit.
Authors: Kim Hong‐Seok , Do Kyung Soon , Kim Ki Soon , Shim Jun Ho , Cha Geung Sig , Nam Hakhyun
Published: February 2005

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Stereospecific Deoxygenation of Phosphine Oxides with Retention of Configuration Using Triphenylphosphine or Triethyl Phosphite as an Oxygen Acceptor.
Authors: Wu Hai‐Chen , Yu Jin‐Quan , Spencer Jonathan B.
Published: February 2005

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Synthesis of Quinoline‐8‐selenol, Its Complex Compounds with Metals and Their Cytotoxic Activity.
Authors: Ashaks J. , Bankovsky Yu. , Zaruma D. , Shestakova I. , Domracheva I. , Nesterova A. , Lukevics E.
Published: February 2005

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Preparation of γ‐Siloxyallyltributylstannanes and Their Use in the Synthesis of (.+‐.)‐1‐Deoxy‐6,8a‐di‐epi‐castanospermine.
Authors: Chevallier Floris , Le Grognec Erwan , Beaudet Isabelle , Fliegel Florian , Evain Michel , Quintard Jean‐Paul
Published: February 2005

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Nickel‐Catalyzed Acylstannylation and Alkynylstannylation of 1,2‐Dienes.
Authors: Nakao Yoshiaki , Shirakawa Eiji , Tsuchimoto Teruhisa , Hiyama Tamejiro
Published: February 2005

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Novel Sesterterpenes from Leucosceptrum canum of Nepalese Origin.
Authors: Choudhary Muhammad Iqbal , Ranjit Rosa , Atta‐ur‐Rahman Atta‐ur‐Rahman , Hussain Sajjad , Devkota Krishna Prasad , Shrestha Tirtha Maiya , Parvez Masood
Published: February 2005

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An Improved Protocol for the SmI2‐Promoted C‐Alkylation of Peptides: Degradation and Functionalization of Serine Residues in Linear and Cyclic Peptides.
Authors: Blakskjaer Peter , Gavrila Adina , Andersen Lisbeth , Skrydstrup Troels
Published: February 2005

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Selective Hydroalkoxycarbonylation of Enamides to N‐Acyl Amino Acid Esters: Synthetic Applications and Theoretical Studies.
Authors: Beller M. , et al. et al.
Published: February 2005

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A New Homobifunctional p‐Nitro Phenyl Ester Coupling Reagent for the Preparation of Neoglycoproteins.
Authors: Wu Xiangyang , Ling Chang‐Chun , Bundle David R.
Published: February 2005

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CamTHP*OH: A Camphor‐Derived δ‐Lactol Auxiliary for the Effective Desymmetrization of Attached Glycinamide Residues. Asymmetric Synthesis of α‐Amino Carbonyl Compounds.
Authors: Dixon Darren J. , Horan Richard A. J. , Monck Nathaniel J. T.
Published: February 2005

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2‐Haloethyl 1‐Thioglycosides as New Tools in Glycoside Syntheses. Part 1. Preparation, Characteristics, General Reactions.
Authors: Krueger Andreas , Pyplo‐Schnieders Jutta , Redlich Hartmut , Winkelmann Paer
Published: February 2005

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Synthesis of 2‐Amino‐2‐deoxy‐β‐D‐galactopyranosyl‐ (1→4)‐2‐amino‐2‐deoxy‐β‐D‐galactopyranosides: Using Various 2‐Deoxy‐2‐phthalimido‐D‐galactopyranosyl Donors and Acceptors.
Authors: Vesely Jan , Ledvina Miroslav , Jindrich Jindrich , Trnka Tomas , Saman David
Published: February 2005

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Synthesis of 2′,3′‐Dideoxy‐6′,6′‐difluorocarbocyclic Nucleosides
Authors: Yang Yan‐Yan , Meng Wei‐Dong , Qing Feng‐Ling
Published: February 2005

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Down—Regulation of Human Deoxyuridine Triphosphate Nucleotidohydrolase (dUTPase) Using Small Interfering RNA (siRNA)
Authors: Williams M. V. , Studebaker A. W.
Published: February 2005

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Comparison of mRNA Expression Levels Determined with TAQ—Man and Competitive Template RT—PCR
Authors: Mauritz R. , Schwabe W. , Haeusler P. , Noordhuis P. , Smid K. , McLeod H. L. , Behnke D. , van Groeningen C. J. , Peters G. J.
Published: February 2005

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Intracellular Thymidylate Synthase Inhibition by Trifluorothymidine in FM3A Cells
Authors: Temmink O. H. , Comijn E. M. , Fukushima M. , Peters G. J.
Published: February 2005

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5‐Fluoro‐2′‐deoxyuridine Has Effects on Mitochondria in CEM T‐Lymphoblast Cells
Authors: Curbo S. , Johansson M. , Karlsson A.
Published: February 2005

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Combinations of 5‐Fluorouracil with UCN‐01 or Staurosporine
Authors: Sigmond J. , Comijn E. M. , Kamphuis J. A. E. , Peters G. J.
Published: February 2005

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Antiproliterative Activity and Mechanism of Action of Fatty Acid Derivatives of Arabinosylcytosine (ara‐C) in Leukemia and Solid Tumor Cell Lines
Authors: Bergmann A. M. , Kuiper C. M. , Myhren F. , Sandvold M. L. , Hendriks H. R. , Peters G. J.
Published: February 2005

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Combination Chemotherapy of BCNU and Didox Acts Synergystically in 9L Glioma Cells
Authors: Horvath Zsuzsanna , Bauer Wolfgang , Hoechtl Thomas , Saiko Philipp , Fritzer‐Szekeres Monika , Tihan Tarik , Szekeres Thomas
Published: February 2005

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Cyclic Nucleotides and Neuroblastoma Differentiation
Authors: Messian E. , Lupi F. , Barile L. , Giacomello A.
Published: February 2005

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2‐Alkyl‐2‐hydroxymethyl‐1,3‐propanediols in the Synthesis of Phospholipids
Authors: Savin G. A. , Kutsemako O. M.
Published: February 2005

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Novel Mannich Ketones of Oxazolidinones as Antibacterial Agents.
Authors: Srivastava Brijesh Kumar , Kapadnis Prashant B. , Pandya Purvi , Lohray Vidya Bhushan
Published: February 2005

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Synthesis of Nanomaterials Using Microemulsion Process
Authors: Kuiry Suresh C. , Seal Sudipta
Published: February 2005

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Inorganic Nanomaterials from Molecular Templates
Authors: Mathur Sanjay , Shen Hao
Published: February 2005

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Inorganic Fullerene‐Like Structures and Inorganic Nanotubes from 2‐D Layered Compounds
Authors: Tenne R.
Published: February 2005

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N—Rb (Nitrogen—Rubidium)
Authors: Sangster James
Published: February 2005

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Fundamentals of Biphasic Reactions in Water
Authors: Oenal Yuecel , Baerns Manfred , Claus Peter
Published: February 2005

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Organic Chemistry in Water
Authors: Lubineau Andre , Auge Jacques , Scherrmann Marie‐Christine
Published: February 2005

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Introduction
Authors: Cornils Boy , Herrmann Wolfgang A.
Published: February 2005

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The Use of Quasi‐Enantiomeric Isotopomers as Chiral Probes for Determining Stereoisomeric Purity
Authors: Eames Jason , Suggate Michael J.
Published: February 2005

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The α‐Hydroxy Ketone (α‐Ketol) and Related Rearrangements
Authors: Paquette Leo A. , Hofferberth John E.
Published: February 2005

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Raffaella Volpicelli and Livius Cotarca of the Zambon Group Look at a Key Area of Asymmetric Chemistry. Second Order Asymmetric Resolutions
Authors: Volpicelli Raffaella , Cotarca Livius
Published: February 2005

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Isocyanides and Related Compounds
Authors: Suginome M. , Ito Y.
Published: February 2005

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Introduction of the Cyano Group by Conjugate Addition
Authors: Podlech J.
Published: February 2005

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Introduction of the Cyano Group by Addition to an Imino Group
Authors: North M.
Published: February 2005

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Introduction of the Cyano Group by Addition to a Carbonyl Group
Authors: North M.
Published: February 2005

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Introduction of the Cyano Group by Substitution of Oxygen Functions
Authors: Subramanian L. R.
Published: February 2005

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Construction of the Cyano Group by Functional Group Transformation from a Nitrogen‐Containing Starting Material
Authors: Subramanian L. R.
Published: February 2005

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Construction of the Cyano Group by Functional Group Transformation from a Nitrogen‐Free Starting Material
Authors: Subramanian L. R.
Published: February 2005

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The Molecular Basis of Olfactory Chemoreception
Authors: Meierhenrich Uwe J. , Golebiowski Jerome , Fernandez Xavier , Cabrol‐Bass Daniel
Published: February 2005

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Prolegomena to Future Experimental Efforts on Genetic Code Engineering by Expanding Its Amino Acid Repertoire
Authors: Budisa Nediljko
Published: February 2005

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Beta‐Strand Mimetics
Authors: Loughlin Wendy A. , Tyndall Joel D. A. , Glenn Matthew P. , Fairlie David P.
Published: February 2005

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Zero‐field Splitting
Authors: Neese Frank
Published: February 2005

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Characterizing Two‐Bond NMR 13C—15N, 15N—15N, and 19F—15N Spin—Spin Coupling Constants Across Hydrogen Bonds Using ab initio EOM—CCSD Calculations
Authors: Del Bene Janet E.
Published: February 2005

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NMR Parameters in Proteins and Nucleic Acids
Authors: Case David A.
Published: February 2005

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Acid—Base Properties of Purine Residues and the Effect of Metal Ions: Quantification of Rare Nucleobase Tautomers
Authors: Sigel Helmut
Published: February 2005

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Tubulin content and synthesis in differentiating drosophila cells in culture
Authors: Berger Edward M. , Sloboda Roger D. , Ireland Robert C.
Published: February 2005

Drosophila Kc cells exposed to physiological doses of the moulting hormone, β‐ecdysone, elongate, become motile, and subsequently aggregate. This pattern of morphogenesis was found to require the assembly of a microtubular cytoskeleton. Tubulin content was significantly increased in hormone‐treated cells when compared to controls, as measured by a 3H‐colchicine‐binding assay. However, determinations of rates of tubulin synthesis and breakdown revealed no difference between control and hormone‐treated cells for either parameter. When tubulin content was assayed by methods that do not depend on colchicine‐binding activity, no difference between hormone‐treated and control cells was observed. These results are discussed in terms of a model in which β‐ecdysone affects the distribution of tubulin in “assembly‐active” and “assembly‐inactive” pools.
Invited review: Guidance cue patterns and cell migration in muiticeliuiar organisms
Authors: Katz Michael J. , Lasek Raymond J.
Published: February 2005

In multicellular organisms, guidance cues are either diffusible molecules or cellular or extracellular surfaces that are found in reproducible locations and that orient migrating cells and cell processes. The pattern of the guidance cues usually determines the complex in vivo migration routes of motile cells and cell processes. Within organisms, guidance cues are found to be organized in two general patterns: (a) broad gradients ‐ such as diffuse chemotactic gradients; (b) discrete routes (substrate pathways) ‐ such as chemotactic gradients confined to long channels, and such as the axon surface which represents a long specific highway for migrating Schwann cells.
Distribution of tubulin and actin in neurites and growth cones of differentiating nerve cells
Authors: Spooner Brian S. , Holladay Carter R.
Published: February 2005

Embryonic chick nerve cells, from dissociated dorsal root ganglia, were cultured on polylysine substrata and examined for tubulin and actin distribution by indirect immunofluorescence.

Antibodies generated against chick brain tubulin produced specific fluorescence in growth cones, neurites, and cell bodies without revealing distribution differences or substructure in the nerve cells. However, at reduced antitubulin concentrations, differences were resolved. Tubulin fluorescence remained uniform and intense in neurites and cell bodies, but exhibited reduced intensity and patterning in growth cones. Nonneuronal cells in the reduced intensity and patterning in growth cones. Nonneuronal cells in the cultures served as controls for typical cytoplasmic tubulin fluorescence distribution. Straining controls demonstrated that fluorescence resulted from tubulin‐antitubulin binding.

Analogous studies, using antibodies generated against chick brain actin, demonstrated distribution differences at reduced antiactin concentrations, including “hot spots” of intense fluorescence in growth cones and a paucity of fluorescence in neurites.
Microtubule sliding in cilia of the rabbit trachea and oviduct
Authors: Dirksen Ellen Roter , Zeira Michael
Published: February 2005

Evidence for active sliding of microtubules during ciliary activity has been demonstrated in a number of organisms: sea urchin sperm flagella, protozoan cilia, and mollusc gill cilia. Although there is evidence that active sliding also occurs in mammalian sperm flagella, there is little or no information on whether active sliding of microtubules also occurs in the short (5‐μm) cilia of the mammalian trachea or oviduct. Since these cilia are important in tracheobronchial clearance and ovum transport, respectively, it has been important to demonstrate that microtubule sliding is also involved in the activity of somatic cilia. Ciliated apical portions (cortices) and cilia were isolated from rabbit trachea and oviduct, using Triton X‐100 to demembranate the cilia. Most of the ciliated cortices reactivated upon addition of ATP, whereas isolated cilia reactivated to a lesser extent. When preparations of cilia were digested with trypsin before or after ATP addition, disintegration of axonemal doublets occurred with about the same frequency as reactivation. These events were recorded using Nomarski optics and dark‐field microscopy. When isolated cilia which had been digested by trypsin and exposed to ATP were also prepared for electron microscopy by negative staining, telescoping of doublet microtubules from axonemes could be shown. These results demonstrate that mammalian somatic ciliary doublet microtubules actively slide in a manner similar to that described for invertebrate cilia.
Effects of Triton‐extraction conditions on beat symmetry of sea urchin sperm flagella
Authors: Okuno M. , Brokaw C. J.
Published: February 2005

Potentially asymmetric spermatozoa are obtained when spermatozoa are demembranated in the presence of a low Ca2+/Mg2+ ion concentration ratio. They swim with asymmetric bending waves even when reactivated at low Ca2+ concentrations, and become more asymmetric when Ca2+ is increased. Potentially symmetric spermatozoa, which swim with symmetric bending waves at low Ca2+ and become asymmetric as the Ca2+ is increased, can be obtained by exposing the flagella to a high Ca2+/Mg2+ ratio, either during or subsequent to demembranation. The rate of this conversion is an increasing function of temperature and Triton concentration. Potentially symmetric spermatozoa can be reconverted to potential asymmetry, if the exposure to high Ca2+/Mg2+ is brief, and is terminated by addition of EGTA and Mg2+ before diluting the spermatozoa. The conversion to potential symmetry may involve removal of a labile component from the axoneme.
Abnormal myosin heavy chain variant associated with avian muscular dystrophy
Authors: Rushbrook Julie Ivory , Yuan Anna I , Stracher Alfred
Published: February 2005

Avian muscular dystrophy is characterized by the degeneration of fast white skeletal muscle fibers, with onset during development. Using a one‐dimensional peptide mapping technique, we have detected two forms of the myosin heavy chain in the fast white fibers of adult domestic chickens, one form characteristic of birds homozygous for muscular dystrophy, the other of their normal controls. Four dystrophic strains carrying the same gene for muscular dystrophy were examined.

No differences were detected in the embryonic heavy chain peptide maps of normal and dystrophic chickens, consistent with the developmental onset of the condition. Differences were also absent from the peptide maps of heavy chains from slow red fibers, which are unaffected in dystrophy. No dystrophy‐specific peptide map differences were detected in the three light chains. Analysis of peptide maps of rod and the heavy chain component of subfragment‐1 from normal and dystrophic heavy chains indicates the presence of amino acid sequence differences in the two proteins.
Invited review: The role of nucleotide triphosphate in actin and tubulin assembly and function
Authors: Weisenberg Richard C.
Published: February 2005

Both actin and tubulin, the major proteins of the cytoskeleton, bind nucleotide triphosphate (NTP) and exhibit the phenomenon of “polymerization‐coupled” NTP hydrolysis. In this report I review the nature of polymerization‐coupled NTP hydrolysis, and its possible role in the cellular function of actin and tubulin. Polymerization‐coupled hydrolysis may be viewed as simply reflecting differences in the NTPase activity of free subunit as compared to polymer. Making assumptions concerning the values of various rate constants, it is possible to write expressions for the effects of NTP hydrolysis on the kinetics of polymerization. The role of NTP hydrolysis may be viewed in at least three different ways: (1) Hydrolysis alters the kinetics of assembly and disassembly. This leads to a consideration of the role of subunit flow in microtubule and microfilament function. (2) Hydrolysis is an essentially irreversible step that separates the assembly and disassembly reactions. This suggests a role of NTP in the regulation of polymer content during cellular cycles of assembly and disassembly. (3) NTP may allow transient stabilization of intersubunit bonds. This suggests a role of NTP in nucleation and possible regulation of nonequilibrium states of assembly.
A motile system of singlet microtubules in spermatozoa
Authors: Baccetti B. , Burrini A. G. , Dallai R. , Pallini V.
Published: February 2005

In this report we demonstrate that in the coccid insects Pseudococcus, Phenacoccus, and Planococcus the whole spermatozoon is made up by a nuclear central core surrounded by two complete and one incomplete turns of concentric microtubule palisades. Microtubules of the outer row are linked by a system of short projections 6 nm long; those of the inner row are linked to each other by similar arms; a second system of 6 nm arms links the tubules of each inner row to those of the respective outer row. All these systems of arms are longitudinally spaced every ∼ 12 nm. The motility of this spermatozoon is due to waves progressing from the posterior extremity to the anterior one. By SDS polyacrylamide gel electrophoresis a group of high molecular weight polypeptides is detected, one of which migrates in coincidence with the A dynein band from sea urchin sperm. Our data suggest that occurrence in coccid spermatozoon of a motility due to singlet tubules‐dynein interaction.
Motive force of cytoplasmic streaming during plasmodial mitosis of physarum polycephalum
Authors: Gotoh Kuniyasu , Kuroda Kiyoko
Published: February 2005

The relationship between mitosis and cytoplasmic streaming in the plasmodium of Physarum polycephalum was investigated by simultaneously conducting the following three experiments: (1) identification of the mitotic stages under phase contrast optics, (2) measurement of the rate of oriented migration of the plasmodium on an agar ribbon, and (3) measurement of the motive force of cytoplasmic streaming by the double‐chamber method of Kamiya.

The migration of the plasmodium almost stopped during synchronous mitosis and the motive force of the flow decreased to 1/4 of the normal level in this period. Gelation of the endoplasm did not occur during the mitotic period, and thus the cessation of the plasmodial migration must have been caused by the diminution of the motive force responsible for cytoplasmic streaming.
Chromosome movement during meiotic prophase in crane‐fly spermatocytes. I. Observations on living cells and the effects of cyanide and cold treatment
Authors: Lafountain James R.
Published: February 2005

Meiotic prophase in spermatocytes of the crane fly, Nephrotoma suturalis, involves both the condensation and the movement of bivalent chromosomes. Since crane flies have only four bivalents that appear highly condensed during late prophase, changes of position and orientation of those bivalents relative to one another can be seen easily in living cells. Chromosome movement during the final 1 to 2 hr of diakinesis was analyzed in detail. Maximal velocities of prophase movements were between 0.1 and 1 μM/min. Metakinetic movements during prometaphase have similar velocities. To assess the physiological basis of prophase movements, experiments employing cyanide and cold treatment were performed. Prophase movements were abolished completely by cyanide, and, for the most part, the velocities of chromosomes in the cold at 2°C and 6°C were less than that of untreated cells at 22°C. The results suggest that prophase movements are energy dependent and may involve an enzyme‐catalyzed process occurring in close association with the nuclear envelope.
Multiple effects of ethanol and 5‐hydroxytryptamine on the gill cilia of mytilus edulis
Authors: Sanderson Michael J. , Satir Peter
Published: February 2005

The lateral (L) cilia on an isolated filament from the gill of Mytilus edulis remain arrested at the end of their recovery stroke (hands up) when perfused with artificial sea water (ASW). The laterofrontal (LF) cilia continue to be active. The addition of 10% ethanol (ETOH) to the ASW perfusate arrests the LF cilia in a hands‐up posture; the L cilia remain undisturbed. By contrast, 10−6 M 5‐hydroxytryptamine (5HT) in ASW activates the L cilia and arrests the LF cilia at the end of their effective stroke (hands down). Continued perfusion with 10% ETOH (v/v) in ASW/5HT restores activity to the LF cilia but arrests the L cilia (hands up). These effects are reversible and independent of external Ca2+.

Following the detergent extraction of the filament, all gill cilia are inactive. The addition of 0.2 mM ATP in the presence of low Ca2+ (< 10−7 M) reactivates all model cilia. Under these conditions, 5HT can no longer inhibit the activity of LF cilia and is not required for the activation of the L cilia. This suggests that 5HT acts at a membrane level. An increase in free Ca2+ (> 10−6 M) arrests the L cilia hands up; the LF cilia remain active. Further Ca2+ increase (> 10−3 M) induces hands‐up arrest of the LF cilia, confirming that the Ca2+ threshold of the two ciliary types is different by several orders of magnitude.

The addition of 10% ETOH in low Ca2+ to demembranated reactivated cilia arrests the L cilia hands up while the LF cilia continue to beat. Ten percent ETOH appears to interact with the axoneme, mimicking the effect of high Ca2+ and with the membrane to increase Ca2+ permeability and possibly to inactivate 5HT receptors. These results are discussed in terms of axonemal switching mechanisms and the physiological control of filter feeding in the lamellibranch gill.
In situ demonstration of actin in normal and injured ocular tissues using 7‐nitrobenz‐2‐oxa‐1,3‐diazole phallacidin
Authors: Gordon Sheldon R. , Essner Edward , Rothstein Howard
Published: February 2005

The fluorescent derivative of the actin‐binding toxin phallacidin, 7‐nitrobenz‐2‐oxa‐1,3 diazole phallacidin, has been used to cytologically demonstrate the presence of actin in lens epithelium, corneal endothelium, and retinal pigment epithelium. In these noninjured tissues, no stress fibers are observed and fluorescence is confined mainly to an area at or near the cell membrane, although some diffuse cytoplasmic staining can also be seen. However, following injury to either the lens epithelium or corneal endothelium of rats and frogs, stress fibers are detected, but only in those cells that migrate into the wound area. Cells on the periphery of each tissue do not partake in would repair and thus maintain their normal appearance. After the tissue has regenerated, stress fibers disappear, and those cells involved in the injury response return to their normal morphology.

When rabbit corneal endothelium is placed in tissue culture, stress fibers are observed as the cells migrate away from the initial explant. Upon reaching confluency, these cells spread out and each is surrounded by thick actin‐containing bands. Furthermore, they exhibit some stress cables within their cytoplasm. This is in contrast to their appearance in vivo where stress fibers are absent and fluorescence is limited to a region near the cell membrane.
Motility of the 6 + 0 flagellum of lecudina tuzetae
Authors: Goldstein Stuart F. , Schrével Joseph
Published: February 2005

The male gametes of the parasitic protozoan, Lecudina tuzetae, have a motile flagellum with a “6 + O” ultrastructure ‘Schrével and Besse, 1975’. These gametes were isolated from the cysts in which they develop and were observed and photographed under a variety of conditions. The flagella beat continuously, without stopping and starting, with a beat period of about 2 sec. They can beat in solutions whose viscosities are greater than 0.5 Nsm−2 (l Nsm−2 = 103 cP). The waveform can be approximated by a series of helical arcs and interconnecting straight regions that travel from the base to the tip. The helical regions have a radius of curvature of 3.2 μm and subtend a final angle of 1.7 radians. The straight portions are 2.0 μm in length. There are two sets of opposing bends, but they do not originate in the same plane. The resulting waveform is an approximately helical coil, with a pitch of 9.8 μm, a pitch angle of 0.6 radian and a peak‐to‐peak amplitude of 2.3 μm. The sense of the coil is left handed. The axoneme twists during beating. The main differences between the movement of this flagellum and that of typical 9 + 2 flagella are a low beat frequency and three‐dimensional bends that produce relatively little forward movement of the cell. Twisting is discussed as a means of discriminating between some types of models of flagellar motility.
Three‐dimensional organization of microtubules and microfilaments of the basal body apparatus of ciliated respiratory epithelium
Authors: Gordon Ronald E.
Published: February 2005

This is a descriptive study showing the three‐dimensional interrelationship of cytoskeletal elements at the apex of ciliated cells of rat respiratory epithelium. Tissue specimens were serially thin sectioned in various planes and examined by transmission electron microscopy. Thicker sections were also cut at various angles and analyzed stereoscopically. Other specimens were cleared of soluble molecules by glycerination or Triton‐X 100 treatment and sectioned as described above. It was found that C microtubules from the triplets of each basal body diverge from the A and B microtubules, run a short distance, and converge at the basal foot. These microtubules or other microtubules arising anew then dispersed deeper into the cytoplasm. The C fibers also interdigitated with other microtubules running perpendicular to them and parallel to the ciliated surface. Ten‐nanometer intermediate filaments were organized in parallel sheets between adjacent basal bodies. Sixnanometer actin filaments were distributed throughout the apical cytoplasm. Neighboring basal bodies were linked to one another by microtubules and microfilaments. Basal bodies from each cell appear to be structured for stability, flexibility, and arranged to operate as a single unit.
Effects of trifluoperazine upon the calcium‐dependent ciliary arrest response of freshwater mussel gill lateral cells
Authors: Reed William , Lebduska Stephen , Satir Peter
Published: February 2005

Calmodulin (CaM) isolated from freshwater mussel gill has been shown to be present in fractions derived solely from epithelial cells of whole gill tissue. This CaM has been used to activate bovine brain phosphodiesterase (PDE) and the dose dependence of trifluoperazine‐dihydrochloride (TFP)‐mediated inhibition of activation has been investigated. The dose‐response curve yields an apparent K1 of 20 μM and suggests that at low concentration (up to 40 μM) TFP inhibits PDE activity in the presence of Ca2+, not by direct action on the enzyme, but by a shunt that negates the effect of mussel gill CaM.

To determine whether CaM is physiologically significant for ciliary activity in the mussel gill, the effect of TFP upon the Ca2+‐dependent ciliary arrest response of the lateral (L) cells of the gill has been examined. Detergent‐treated permeabilized epithelial L cell models are scored for ciliary activity after transfer to reactivation solutions that vary in their free Ca2+ and TFP content. At 10−5 M free Ca2+ (pCa 5), maximum recovery from arrest is observed for TFP concentrations in the range of 25 to 30 μM. TFP‐mediated recovery from arrest is never complete, suggesting that in the presence of sufficient Ca2+ the drug irreversibly damages a certain fraction of axonemes. At pCa 7 the cilia reactivate and 25–30.
Electromechanical coupling in cilia I. Effects of depolarizing voltage steps
Authors: De Peyer Jacques E. , Machemer Hans
Published: February 2005

We have studied quantitative aspects of ciliary motor responses to membrane depolarization in the ciliate Stylonychia using voltage clamp and high‐speed cinematograhpy techniques and employing computer‐processing methods for evaluation. Depolarizations beyond 4 mV activate the cirri (compound cilia) which are at rest in the absence of a stimulus. The power stroke of activiated cirri is oriented toward the cell anterior. The frequency and duration of beating increase with rising depolarization. With very large positive stimuli (≥ 150 mV) activation of the response is delayed until the end of the voltage step (“off‐response”). The peak frequecy is essentially unaltered during sustained depolarization. The frequency drops exponentially following repolarization of the membrane. The time constant of the decay in ciliary activity rises with the amplitude, not with the duration of the depolarization. The ciliary motor response is most adequately represented by the number of evoked ciliary cycles (ciliary work), and appears to be related to the amplitude of the depolarization.
Electromechanical coupling in cilia II. Effects of hyperpolarizing voltage steps
Authors: De Peyer Jacques E. , Machemer Hans
Published: February 2005

We have studied the motor responses to membrane hyperpolarization of the marginal cirri in Stylonychia using voltage‐clamp, high‐speed cinematography, and computer‐processing techniques. The cirri started beating when voltage step amplitudes rose beyond 5 mV. The power stroke was oriented toward the posterior cell and (hyperpolarizing motor activation). The frequency rose slightly during a voltage step, and decreased with similar rates for 100 ms following the step end. Amplitude and duration of the step tended to increase the motor response of the cirri. The late response declined exponentially. The time constant of the decay rose with the step amplitude. Among three response parameters tested (frequency, duration, number of cycles), the number of evoked ciliary cycles was best correlated with the amplitude of the hyperpolarization. Comparisons with the responses to depolarizing voltage steps reveal similarities in the relaxation of ciliary activity which appears to be uncoupled, in part, from the electric membrane events during the voltage stimulus.
Microtubule capping structures at the tips of tracheal cilia: Evidence for their firm attachment during ciliary bend formation and the restriction of microtubule sliding
Authors: Dentler William L. , Lecluyse E. L.
Published: February 2005

The distal tips of the central pair and A‐microtubules are capped in mammalian and avian tracheal cilia. The capping structures are similar to those found in protozoan cilia and flagella [Dentler, 1981], and consist of a central microtubule cap that links the central microtubules to the membrane or to the ciliary crown and A‐microtubule plugs that insert into the lumen of each of the A‐microtubule plugs is bound to the central microtubule cap by distal filaments. The ends of the central and outer doublet microtubules are tightly bound to the cap in both intact and in demembranated and reactivated tracheal cilia. Analysis of the displacement of the microtubule tips in cilia fixed at various bend angles revealed that the displacements of A‐microtubules are only partially in agreement with those predicted by the sliding filament model [Satir, 1968]. These results are discussed with respect to the regulation of microtubule sliding in capped cilia and the role of the microtubule capping structures in microtubule assembly.
The intracellular movement of endocytic vesicles in cultured granulosa cells
Authors: Herman Brian , Albertini David F.
Published: February 2005

Ligand binding to cell surface receptors induces rapid internalization of ligandreceptor complexes by receptor mediated endocytosis. We have examined the intracellular movement of endocytic vesicles, induced by the lectin concanavalin A (Con A), in cultured rat ovarian granulosa cells using fluorescence and electron microscopy. Within 20 minutes of ligand treatment at 37°C, numerous Con A‐containing endocytic vesicles form, which migrate to the cell center by 60 minutes. Double label fluorescence microscopy, using fluorescien‐Con‐A and rhodamine immunofluorescent staining of tubulin or vimentin, indicates that during vesicle migration microtubules and 10‐nm filaments are altered in their organization. By 30 minutes, vesicles are associated with microtubule bundles, which subsequently collapse around the nucleus. Similarly, 10‐nm filaments accumulate around the nucleus in conjunction with the perinuclear aggregation of endocytic vesicles. Electron microscopy of Con A‐horseradish peroxidase‐labeled cells demonstrates that endocytic vesicles fuse to form large receptosome‐like structures during intracellular migration and these structures are associated with cytoplasmic microtubules and 10‐nm filaments. Taxol, a drug that stabilizes microtubules, prevents endocytic vesicle translocation to the Golgi region. Nocodazole, which causes microtubule disassembly, results in the collapse of 10‐nm filaments and the central aggregation of endocytic vesicles. The data indicate that the cytoskeleton participates in the directed intracellular movement of endocytic vesicles; the possible subcellular basis for this movement is discussed.
Two different monoclonal antibodies to alpha‐tubulin inhibit the bending of reactivated sea urchin spermatozoa
Authors: Asai David J. , Thompson William C. , Wilson Leslie , Brokaw Charles J.
Published: February 2005

Two monoclonal antibodies reactive for α‐tubulin but not for β‐tubulin have been prepared, characterized in terms of their relative binding to tubulins from differnt sources by a solid‐phase binding assay, immunoautoradiography, and indirect immunofluorescence, and utilized to study flagellar motility. Our results demonstrate that α‐tubulins from different species, and even from different tissues of the same species, are nonidentical. Especially interesting was the observation that one of the antibodies, Ab2, immunofluorescently stained microtubules of chick embryo fibroblast cells, but was completely unreactive for microtubules of rat kangaroo (PtK2) fibroblasts; a different antibody, Ab1, stained both cell types. Results of these and additional experiments clearly show that Ab1 and Ab2 recognize discrete and different epitopes on α‐tubulin.

Monoclonal antitubulins Ab1 and Ab2 each inhibited the bend amplitude of reactivated sea urchin spermatozoa without affecting beat frequencies or the ability of the outer doublet microtubules to slide past each other in elastase‐digested models. These results, together with those obtained previously using rabbit polyclonal antitubulin antibodies [Asai and Brokaw, 1980], demonstrate that inhibition of bend amplitude is a common property of antitubulin antibodies and is not due to the binding of antibodies to one specific site on the axoneme. Our results suggest that tubulin subunit conformational changes may occur on the outer doublet lattice and may be integrally involved in the mechanism and control of flagellar bending.
Identification of fibrinogen derivatives in the triton‐insoluble residue of human blood platelets
Authors: Casella J. F. , Masiello N. C. , Lin S. , Bell W. , Zucker M. B.
Published: February 2005

Several proteins (eg, actin, myosin, and actin‐binding protein) in the Tritoninsoluble residue of thrombin‐stimulated platelets are important in the formation of cytoskeletal structures. Electrophoretic analyses have shown that unidentified protein bands of 68,000, 55,000, and 48–50,000 daltons are also present in larger amounts after thrombin stimulation. Since these molecular weights correspond roughly to those of the α, β, and γ chains of fibrin, and since fibrinogen is found in platelet α‐granules, these bands were compared to those obtained when purified fibrinogen was treated with thrombin, exposed to 1% Triton X‐100‐5 mM EGTA, and the resultant Triton‐insoluble residue sedimented. Identification of the 68,000‐, 55,000‐, and 48‐‐50,000‐dalton bands as fibrinogen derivatives was confirmed by identifying them in comigration studies and in autoradiographs of Triton‐insoluble residues of platelets that were electrophoretically transferred to nitrocellulose paper and treated with antifibrinogen antibody and 125I‐protein A. Furthermore, if the platelet suspension was treated with thrombin in the presence of calcium ions, protein bands characteristic of the action of Factor XIII on fibrin were observed, active platelet Factor XIII apparently having been made available by lysis of platelets during preparation. Making use of the electrophoretic properties of tubulin recently described by Best et al [1981], comigration studies using hog brain tubulin indicated that tubulin is not present in significant amounts in the Triton‐insoluble residue of platelets as previously suggested. The identification of these proteins as fibrinogen derivatives does not demonstrate a physiological interaction between fibrin and the platelet cytoskeleton, since fibrin is Tritoninsoluble and can be pelleted even in the absence of platelet cytoskeletons.
Flagellar rootlets as myonemal elements for pusule contractility in dinoflagellates
Authors: Cachon Jean , Cachon Monique , Boillot Annie
Published: February 2005

Flagellar rootlets play an important role in “primitive motile systems.” They are made of filaments able to contract by twisting and Ca+2 binding. The pusules of Dinoflagellates appear to be under the control of large bundles of 2.4 nm nonactin filaments that correspond to the striated rootlets of their two flagella.
Nocodazole pretreatment in anaphase selectively reduces anaphase B in PtK1 cells
Authors: Snyder Judith A. , Vogt Sandra I. , McLelland Sandra L.
Published: February 2005

During early anaphase PtK1 cells were briefly treated with the rapidly reversible microtubule (MT) poison nocodazole. This treatment abruptly stopped chromosome motion and effected a large decrease in spindle birefringence. On removal of the drug, chromosome to pole motion (anaphase A) returned, though at a lesser rate but not extent than untreated cells. In most cases elongation of the pole‐pole distance (anaphase B) also occured, at both a rate and to an extent less than in untreated cells. During the recovery period following drug arrest spindle birefringence did not return to pretreatment levels. Electron microscopic analysis of nocodazole arrested, or arrested and released, cells revealed extensive disassembly of the nonkinetochore class of MTs (nkMTs), particularly evident in the astral region. Microtubules seen in the interzone region were largely fragments of midbody precursors. Kinetochore MTs (kMTs) appeared to be unaffected by the brief drug treatment chosen for these experiments. Analysis of MT profiles seen in transverse sections of the interzone region indicated in treated and released cells approximately 60% fewer MTs. This may suggest that chromosome motion during anaphase is not dependent on interactions between kMTs and nkMTs and separation of the spindle poles can occur in the presence of disrupted interzonal MTs.