bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solution structures of stomoxyn and spinigerin, two insect antimicrobial peptides with an α‐helical conformation
Authors: Landon Céline , Meudal Hervé , Boulanger Nathalie , Bulet Philippe , Vovelle Françoise 
Published: September 2005

AbstractStomoxyn and spinigerin belong to the class of linear cysteine‐free insect antimicrobial peptides that kill a range of microorganisms, parasites, and some viruses but without any lytic activity against mammalian erythrocytes. Stomoxyn is localized in the gut epithelium of the nonvector stable fly that is sympatric with the trypanosome vector tsetse fly. Spinigerin is stored and secreted by hemocytes from the fungus‐growing termite. The structure of synthetic stomoxyn and spinigerin in aqueous solution and in TFE/water mixtures was analyzed by CD and NMR spectroscopy combined with molecular modeling calculations. Stomoxyn and spinigerin adopt a flexible random coil structure in water while both assume a stable helical structure in the presence of TFE. In 50% TFE, the structure of stomoxyn is typical of cecropins, including an amphipathic helix at the N‐terminus and a hydrophobic C‐terminus with helical features that probably fold in a helical conformation at higher TFE concentration. In contrast to stomoxyn, spinigerin acquires very rapidly a helical conformation. In 10% TFE the helix is highly bent and the structure is poorly defined. In 50% TFE, the helical structure is well defined all along its sequence, and the slightly bent α‐helix displays an amphiphilic character, as observed for magainin 2. The structural similarities between stomoxyn and cecropin A from Hyalophora cecropia and between spinigerin and magainin 2 suggest a similar mode of action on the bacterial membranes of both pairs of peptides. Our results also confirm that TFE induces helix formation and propagation for amino acids showing helical propensity in water but also enhances the helix propagation propensity of nonpolar β‐branched residues. © 2005 Wiley Periodicals, Inc. Biopolymers 81: 92–103, 2006This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Examination of dye–protein interaction by gel‐permeation chromatography
Authors: Sereikaite Jolanta , Bumelis Vladas‐Algirdas 
Published: September 2005

AbstractThe interaction of Cibacron blue F3G‐A with two therapeutic proteins, recombinant human growth hormone and recombinant human interferon‐α2b, has been examined by applying gel‐permeation chromatography in combination with the absorption difference spectroscopy. The complexes of these proteins with Cibacron blue F3G‐A have been isolated, and their absorbance spectra have been registered. The influence of Cibacron blue F3G‐A on the oligomeric state of proteins has been investigated. It was found that Cibacron blue F3G‐A promotes the generation of interferon‐α2b dimers at pH 5.0. Copyright © 2005 John Wiley & Sons, Ltd.
Aza‐Annulation of Polarized N,S‐ and N,N‐Ketene Acetals with Itaconic Anhydride: Synthesis of Novel Functionalized 1,2,3,4‐Tetrahydro‐2‐pyridones and Related Azabicycles.
Authors: Chakrabarti Sriparna , Panda Kausik , Misra Nimesh C. , Ila Hiriyakkanavar , Junjappa Hiriyakkanavar 
Published: September 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
Synthesis of Fluorous Nitrogen Ligands and Their Metal Complexes as Precatalysts for Applications in Alkane, Alkene, and Alcohol Oxidation, and Atom Transfer Radical Reactions
Authors: Vincent Jean‐Marc , Lastecoueres Dominique , Contel Maria , Laguna Mariano , Fish Richard H. 
Published: September 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
Catalytic enantioselective addition of indoles to arylnitroalkenes: An effective route to enantiomerically enriched tryptamine precursors
Authors: Bandini Marco , Garelli Andrea , Rovinetti Matteo , Tommasi Simona , Umani‐Ronchi Achille 
Published: September 2005

AbstractA new valuable catalytic protocol for the preparation of synthetically useful β‐indolyl nitro compounds bearing benzhydryl stereocenters is presented. The combined use of catalytic amounts of a commercially available chiral [SalenAlCl] complex and pyridine allowed, for the Friedel–Crafts alkylation reaction of indoles with aromatic nitro‐olefins to be carried out in good yields and enantioselectivity (up to 63% ee). © 2005 Wiley‐Liss, Inc. Chirality 17:522–529, 2005.
Chromosomal imbalances in laryngeal and hypopharyngeal cancers detected by comparative genomic hybridization
Authors: Juhász Attila , Balázs Margit , Sziklay István , Rákosy Zsuzsa , Treszl Andrea , Répássy Gábor , Ádány Róza 
Published: September 2005

AbstractBackgroundThe prognostic divergence of laryngeal and hypopharyngeal carcinomas is well known. Hypopharyngeal tumors are characterized by frequent metastasis formation and local recurrence, which is the source of the unfavorable prognosis of this subtype. The aim of this study was to define chromosomal alterations associated with the aggressive behavior of hypopharyngeal tumors.MethodsTwenty‐nine head and neck squamous cell carcinomas (larynx n = 14 and hypopharynx n = 15) were analyzed by comparative genomic hybridization (CGH). Fluorescence in situ hybridization (FISH) was used to validate the CGH data and to compare the amplification pattern of the most frequently altered gene (cyclin‐D1, CCND1) located on 11q13.ResultsThe average number of genetic alterations was significantly higher in the hypopharyngeal tumors (P = 0.02). A good correlation of FISH and CGH data were seen. Gains on 11q13 were present in both subtypes, whereas amplification of CCND1 was associated with the aggressive phenotype by FISH. Chromosomal alteration, which was rarely detected in hypopharyngeal tumors but was observed in more than 50% of laryngeal carcinomas, was 8q gain.ConclusionOur CGH and FISH data show that head and neck squamous cell carcinomas contain complex cytogenetic alterations and further support the hypothesis that different molecular pathways are responsible for the progression of differently localized tumors of the upper aerodigestive tract. © 2005 International Society for Analytical Cytology
Flow cytometer in the infrared: Inexpensive modifications to a commercial instrument
Authors: Stewart Carleton C. , Woodring Mitchell L. , Podniesinski Edward , Gray Brian 
Published: September 2005

AbstractBackgroundThe application of molecules that fluoresce in the infrared (IR) region to measure cell products would be enhanced by a flow cytometer capable of measuring them. To our knowledge, none exist at this time. Accordingly, we have developed such an instrument.MethodsA Becton Dickinson LSR flow cytometer was modified to include a small 785‐nm IR diode laser the size of a C cell battery with 44‐mW output power. The instrument was modified further to accommodate this laser in addition to a 405‐nm solid‐state laser, a 488‐nm air‐cooled argon laser, and a 658‐nm solid‐state laser. Because the IR laser is dangerous to the eye, the laser beams were viewed for optical alignment using a CCD camera and video monitor. An avalanche photodiode was used in place of a photomultiplier tube because its detection sensitivity in the IR region is superior.ResultsTo assess performance, scatter and florescence measurements were made using microspheres that fluoresce in the IR region, and human leukocytes were stained with CD45 biotin followed by a streptavidin conjugated with an IR dye. An avalanche photodiode was 2.3 to 2.8 times more sensitive than a photomultiplier tube for detecting IR fluorescence. Cells stained with CD45 biotin and avidin conjugated with an IR dye could easily be resolved and their fluorescence quantified; there was virtually no autofluorescence. In addition, a lipophilic membrane dye that emits in the IR region was studied. HL60 cells were stained with this dye and they exhibited bright fluorescence intensity.ConclusionA commercial instrument could be modified to accommodate an IR laser for exciting dyes that fluoresce in the IR region. This new capability will extend the range of fluorescence that can be measured by flow cytometry. © 2005 International Society for Analytical Cytology
Selective photoreactions in a programmable array microscope (PAM): Photoinitiated polymerization, photodecaging, and photochromic conversion
Authors: Fulwyler Mack , Hanley Quentin S. , Schnetter Christoph , Young Ian T. , Jares‐Erijman Elizabeth A. , Arndt‐Jovin Donna J. , Jovin Thomas M. 
Published: September 2005

AbstractBackgroundInnovative thinking and experimentation were the hallmarks of Mack Fulwyler's approach to research. This report summarizes some of the ideas and their early realizations that he pursued in the field of imaging cytometry, work that was not published before his untimely death, although he composed the initial draft of this report.MethodsIncluded are related experiments implemented in the programmable array microscope (PAM) devised for patterned illumination and detection, the instrument that Mack Fulwyler employed during a sabbatical leave in Göttingen in 1998. Despite being the originator of instrumentation for flow cytometry and sorting, Mack Fulwyler was intensely interested in imaging systems, recognizing their ability to resolve cellular details obscured by the whole cell signals generally acquired in flow. At one point, these interests merged with those of two other authors (I.T.Y. and T.M.J.), leading to the Image Cytometry and Sorting (ICAS) strategy and project. A major goal was uncomplicated rare cell detection and isolation using a sequential process of cellular labeling via suitable probes, whole field imaging, and selective area‐restricted photoinduced reactions designed to encapsulate and/or chemically or physically tag cells in a manner permitting subsequent fractionation by bulk techniques.Results and ConclusionThis publication features photoinduced polymerization, photodecaging, photoactivation, and photochromic conversion reactions carried out by Fulwyler and/or the other authors with the PAM, employing operator designated patterns and locations in various samples. Photopolymerization of polyethylene glycol‐diacrylate to a gel‐like structure allowing the specific selection of objects (cells) for further analysis and processing techniques was the approach explored personally by Mack Fulwyler in relation to the ICAS concept. © 2005 International Society for Analytical Cytology
Flow cytometric analysis of fluorescence in situ hybridization with dye dilution and DNA staining (flow‐FISH‐DDD) to determine telomere length dynamics in proliferating cells
Authors: Potter Alan J. , Wener Mark H. 
Published: September 2005

AbstractBackgroundTelomeres shorten during DNA replication; extensive erosion of telomeres likely promotes replicative senescence and chromosomal instability. Telomere length in individual cells has been quantified by flow cytometric analysis of fluorescence in situ hybridization (flow‐FISH). To determine the rate of telomere attrition (telomere erosion per cell division), we combined flow‐FISH with dye dilution and DNA staining (flow‐FISH‐DDD) and measured telomere‐specific fluorescence in proliferating cells identified by cell generation and cell cycle phase.MethodsPeripheral blood mononuclear cells (PBMC) were stained with the cell division tracking dye carboxyfluorescein diacetate succinimidyl ester (CFSE), stimulated with phytohemagglutinin (PHA), grown for 5–6 days, hybridized with a telomere sequence‐specific peptide nucleic acid fluorescent probe (PNA‐Cy5), counterstained with DAPI, and analyzed by flow cytometry. The cell cycle distribution and cell division generations were respectively identified by analysis of DAPI emission and deconvolution of CFSE emission, and Cy5 emission was used to determine telomere‐specific fluorescence, an indicator of telomere length, in each cell.ResultsIn stimulated PBMC, in each cell cycle phase, the telomere‐specific fluorescence diminished with increasing cell generation. The rate of decline of the telomere‐specific fluorescence per cell generation did not significantly differ between cell cycle phases.ConclusionsApplication of flow‐FISH‐DDD to measure mean telomere length and the rate of telomere attrition in proliferating cells may find use in studies of ageing and disease, the effects of telomere‐modifying agents, and variability between individuals. © 2005 International Society for Analytical Cytology
Lens and retina formation require expression of Pitx3 in Xenopus pre‐lens ectoderm
Authors: Khosrowshahian Farhad , Wolanski Marian , Chang Wing Y. , Fujiki Kazuhiro , Jacobs Larry , Crawford Michael J. 
Published: September 2005

AbstractPitx3 is expressed in tissues fated to contribute to eye development, namely, neurula stage ectoderm and prechordal mesoderm, then presumptive lens ectoderm, placode, and finally lens. Pitx3 overexpression alters lens, optic cup, optic nerve, and diencephalon development. Many of the induced anomalies are attributable to midline deficits; however, as assessed by molecular markers, ectopic Pitx3 appears to temporarily enlarge the lens field. These changes are usually insufficient to generate either ectopic lenses to enlarge the eye that eventually differentiates. Conversely, use of a repressor chimera or of antisense morpholinos alters early expression of marker genes, and later inhibits lens development, thereby abrogating retinal induction. Reciprocal grafting experiments using wild‐type and morpholino‐treated tissues demonstrate that Pitx3 expression in the presumptive lens ectoderm is required for lens formation. Contradictory to recent assertions that retina can form in the absence of a lens, the expression of Pitx3 in the presumptive lens ectoderm is critical for retina development. Developmental Dynamics 234:577–589, 2005. © 2005 Wiley‐Liss, Inc.
Cross‐presentation of oral antigens by liver sinusoidal endothelial cells leads to CD8 T cell tolerance
Authors: Limmer Andreas , Ohl Jutta , Wingender Gerhard , Berg Martina , Jüngerkes Frank , Schumak Beatrix , Djandji Dominik , Scholz Kai , Klevenz Alexandra , Hegenbarth Silke , Momburg Frank , Hämmerling Günter J. , Arnold Bernd , Knolle Percy A. 
Published: September 2005

AbstractAfter ingestion, oral antigens distribute systemically and provoke T cell stimulation outside the gastrointestinal tract. Within the liver, scavenger liver sinusoidal endothelial cells (LSEC) eliminate blood‐borne antigens and induce T cell tolerance. Here we investigated whether LSEC contribute to oral tolerance. Oral antigens were efficiently cross‐presented on H‐2Kb by LSEC to naive CD8 T cells. Cross‐presentation efficiency in LSEC but not dendritic cells was increased by antigen‐exposure to heat or low pH. Mechanistically, cross‐presentation in LSEC requires endosomal maturation, involves hsc73 and proteasomal degradation. H‐2Kb‐restricted cross‐presentation of oral antigens by LSEC in vivo induced CD8 T cell priming and led to development of CD8 T cell tolerance in two independent experimental systems. Adoptive transfer of LSEC from mice fed with antigen (ovalbumin) into RAG2–/– knockout mice, previously reconstituted with naive ovalbumin‐specific CD8 T cells, prevented development of specific cytotoxicity and expression of IFN‐γ in CD8 T cells. Using a new transgenic mouse line expressing H‐2Kb only on endothelial cells, we have demonstrated that oral antigen administration leads to tolerance in H‐2Kb‐restricted CD8 T cells. Collectively, our data demonstrate a participation of the liver, in particular scavenger LSEC, in development of CD8 T cell tolerance towards oral antigens.
The BTG/TOB family protein TIS21 regulates stage‐specific proliferation of developing thymocytes
Authors: Konrad Mark A. P. , Zúñiga‐Pflücker Juan Carlos 
Published: September 2005

AbstractAs thymocytes undergo differentiation in the thymus, they progress through distinct phases of quiescence and proliferation. Identifying cellular mechanisms that maintain thymocytes in a non‐dividing state is critical to fully understand T cell development. A member of the B cell translocation gene/transducer of ErbB‐2 (BTG/TOB) family of anti‐proliferative proteins was identified as a key mediator of the quiescent state in peripheral anergic and unstimulated T cells. Here, we demonstrate that the BTG/TOB family member TPA‐inducible sequence 21 (TIS21) is expressed in quiescent CD44+CD25– early progenitor thymocytes and CD44–CD25+ cells prior to TCR β‐selection. However, TIS21 expression is decreased in proliferating CD25+CD44+ progenitor thymocytes and CD25lowCD44– β‐selected cells, suggesting that its regulated expression may enable thymocytes to remain quiescent in the absence of mitogenic signals. We addressed the role of TIS21 in regulating thymocyte stage‐specific expansion by ectopically expressing TIS21 in developing thymocytes and hematopoietic progenitors. Dysregulated expression of TIS21 inhibited the expansion of thymocytes even in the presence of endogenous mitogenic signals, while thymocyte differentiation was unimpeded. These findings imply that the intracellular mechanisms regulating thymocyte differentiation and proliferation, which are induced downstream of developmental cues, function independently during early T cell development.
Base‐Induced Trifluoroethanolysis of Acyclic Di‐ and Trihalogeno Ketones: Favorskii Rearrangement and [4+3] Cycloaddition
Authors: Föhlisch Baldur , Franz Thilo , Kreiselmeier Günter 
Published: September 2005

AbstractReactions of five acyclic dihalogeno‐ and trihalogeno ketones, representing the α,α‐, α,α′‐, α,α,α‐ and α,α,α′‐di‐ and trihalogeno substitution pattern, with sodium 2,2,2‐trifluoroethoxide in 2,2,2‐trifluoroethanol (NaTFE/TFE) in the presence of furan were investigated with the aim of obtaining [4+3] cycloadducts of the corresponding oxyallyl intermediates. Preference of Favorskii rearrangement over cycloaddition was observed with dichloromethyl isobutyl ketone (1a) and 1,3‐dibromobutan‐2‐one (12) that formed mainly the trifluoroethyl esters of 3‐chloro‐2‐isopropylpropanoic acid (9a), and (Z)‐but‐2‐enoic acid (isocrotonic acid) (13), respectively. 9a was dehydrohalogenated to form trifluoroethyl 3‐isopropylacrylate (11a). [4+3] Cycloaddition was favored with the 1,1,3‐trihalogenobutan‐2‐ones 24 and 25, leading to 2,4‐dihalogenated 8‐oxabicyclo[3.2.1]oct‐6‐en‐3‐ones (26, 27) as a mixture of endo‐exo‐stereoisomers. With trichloromethyl isobutyl ketone (30) the isomeric 2,4‐dichloro‐substituted oxabicycles (34) were formed in lithium perchlorate/diethyl ether/furan/triethylamine, while in NaTFE/TFE solvolytic displacement of one chloro substituent occurred, providing 2‐chloro‐4‐trifluoroethoxy‐4‐isopropyl‐8‐oxabicyclo[3.2.1]oct‐6‐en‐3‐one (36). By analogy, 27 reacted with sodium methoxide/methanol to form the methoxy‐substituted oxabicycles 39a and 39b. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Postmenopausal hormone therapy and breast cancer risk: The multiethnic cohort
Authors: Lee Sulggi , Kolonel Laurence , Wilkens Lynne , Wan Peggy , Henderson Brian , Pike Malcolm 
Published: September 2005

AbstractEpidemiological studies indicate that menopausal estrogen‐progestin therapy (EPT) use is associated with an increase in breast cancer risk. Further data are needed on whether this association varies by specific prognostic factors and ethnicity. We conducted a cohort study among 55,371 African‐American, Native Hawaiian, Japanese‐American, Latina and White postmenopausal women aged 45–75 years old in the Multiethnic Cohort Study (MEC). A total of 1,615 incident invasive breast cancer cases were identified over an average of 7.3 years. Adjusted relative risks (RRs) were computed for the various forms of hormone therapy (HT). Assuming current users continued HT use to the end of follow‐up, current EPT use was associated with a 29% increased risk of breast cancer per 5 years of use (95% confidence interval (CI) = 23–35%), and current estrogen therapy (ET) use with a 10% increase in risk per 5 years of use (95% CI = 5–16%). These figures increased to only a very small extent when we adjusted for the estimated ˜3% of such women who stop HT use per year of follow‐up. EPT and ET use were associated with greater risk among leaner women, but the increase in risk with EPT use was still very evident in women with BMI ≥30 kg/m2. Current EPT use was associated with increased risk for ER+/PR+, ER+/PR‐ and ER‐/PR‐ tumors. There was little difference in risk by stage of disease or histologic subtype. The increase with EPT use was clearly seen in all 5 ethnic groups; and the increase with ET in 4 of the 5 groups. © 2005 Wiley‐Liss, Inc.
Overexpression of ORC subunits and increased ORC‐chromatin association in transformed mammalian cells
Authors: McNairn Adrian J. , Gilbert David M. 
Published: September 2005

AbstractThe origin recognition complex (ORC) is a conserved heterohexamer required for the formation of pre‐replication (pre‐RC) complexes at origins of DNA replication. Many studies of ORC subunits have been carried out in transformed human cell lines but the properties of ORC in primary cells have not been addressed. Here, we compare the expression levels and chromatin‐association of ORC subunits in HeLa cells to the primary human cell line, WI38, and a virally transformed derivative of WI38, VA13. ORC subunits 2 and 4 were highly overexpressed in both HeLa and VA13, whereas ORC1 levels were elevated in VA13 but considerably higher in HeLa cells. Cellular extraction revealed that the proportion of ORC2 and ORC4 subunits bound to chromatin was similar in all three cell lines throughout the cell‐cycle. In contrast, very little ORC1 was associated with chromatin after extraction of primary WI38 cells, whereas the majority of overexpressed ORC1 in both HeLa and VA13 co‐fractionated with chromatin throughout the cell‐cycle. Although none of the cell lines displayed significant changes in the levels or chromatin‐association of ORC during the cell‐cycle, the chromatin‐associated fraction of ORC1 displayed an increase in apparent molecular weight during S‐phase. Similar experiments comparing immortalized CHO cells to an isogenic virally transformed derivative revealed no changes in levels of ORC subunits but an increase in the proportion of all three ORC subunits associated with chromatin. These results demonstrate a complex influence of cellular immortalization and transformation properties on the expression and regulation of ORC subunits. These results extend the potential link between cancer and deregulation of pre‐RC proteins, and underscore the importance of considering the transformation status of cell lines when working with these proteins. J. Cell. Biochem. © 2005 Wiley‐Liss, Inc.
Force field validation for nucleic acid simulations: Comparing energies and dynamics of a DNA dodecamer
Authors: Jha Shantenu , Coveney Peter V. , Laughton Charles A. 
Published: September 2005

AbstractImportant questions exist regarding the quality of force fields used in molecular dynamics (MD) simulations and their interoperable use with other available MD implementations. NAMD is one of the most efficient and scalable parallel molecular dynamics codes for large‐scale biomolecular simulations in the open source domain. It is the aim of this article to analyze and compare the dynamics of a benchmark DNA dodecamer d(CTTTTGCAAAAG)2 system, including its binding to a specific drug molecule arising from the use of various simulation protocols in NAMD using Amber98, with the dynamics arising from simulations of the same dodecamer using Amber98 in the AMBER package, one of the most well‐established simulation codes for nucleic acids. Based upon a set of validation benchmarks, the details of which are discussed, we find that nucleic acid simulations using NAMD give meaningful results and that the essential features of the resulting dynamics are similar to those arising from the AMBER package. This sets the stage for reliable large‐scale simulations of nucleic acids using NAMD. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 1617–1627, 2005