bluuebunny/crossref_metadata_2025 huggingface dataset:
Nuclear Titin interacts with A- and B-type lamins in vitro and in vivo
Authors: Zastrow Michael S. , Flaherty Denise B. , Benian Guy M. , Wilson Katherine L.
Published: January 2006

Lamins form structural filaments in the nucleus. Mutations in A-type lamins cause muscular dystrophy, cardiomyopathy and other diseases, including progeroid syndromes. To identify new binding partners for lamin A, we carried out a two-hybrid screen with a human skeletal-muscle cDNA library, using the Ig-fold domain of lamin A as bait. The C-terminal region of titin was recovered twice. Previous investigators showed that nuclear isoforms of titin are essential for chromosome condensation during mitosis. Our titin fragment, which includes two regions unique to titin (M-is6 and M-is7), bound directly to both A- and B-type lamins in vitro. Titin binding to disease-causing lamin A mutants R527P and R482Q was reduced 50%. Studies in living cells suggested lamin-titin interactions were physiologically relevant. In Caenorhabditis elegans embryos, two independent C. elegans (Ce)-titin antibodies colocalized with Ce-lamin at the nuclear envelope. In lamin-downregulated [lmn-1(RNAi)] embryos, Ce-titin was undetectable at the nuclear envelope suggesting its localization or stability requires Ce-lamin. In human cells (HeLa), antibodies against the titin-specific domain M-is6 gave both diffuse and punctate intranuclear staining by indirect immunofluorescence, and recognized at least three bands larger than 1 MDa in immunoblots of isolated HeLa nuclei. In HeLa cells that transiently overexpressed a lamin-binding fragment of titin, nuclei became grossly misshapen and herniated at sites lacking lamin B. We conclude that the C-terminus of nuclear titin binds lamins in vivo and might contribute to nuclear organization during interphase.
Trafficking from CD63-positive late endocytic multivesicular bodies is essential for intracellular development of Chlamydia trachomatis
Authors: Beatty Wandy L.
Published: January 2006

Chlamydiae are obligate intracellular bacterial pathogens that replicate solely within the confines of a membrane-bound vacuole termed an inclusion. Within this protected organelle, chlamydiae acquire host-cell-derived biosynthetic precursors necessary for intracellular subsistence, yet the mechanisms and pathways responsible for this acquisition remain elusive. The present study identifies an interaction between the chlamydial inclusion and multivesicular bodies, complex organelles pivotal in protein and lipid transport that are positioned along the endosome-lysosome pathway, and intersect the exocytic pathway in various cell types. Resident protein and lipid constituents of multivesicular bodies colocalized with intracellular chlamydiae, with direct delivery of the resident protein CD63 to the chlamydial inclusion. Interruption of trafficking from multivesicular bodies by pharmacological inhibitors and exogenous antibodies subsequently disrupted sphingolipid delivery to the maturing chlamydial inclusion and intracellular bacterial growth. This study identifies a trafficking pathway from CD63-positive multivesicular bodies to the bacterial inclusion, a novel interaction that provides essential lipids necessary for maintenance of a productive intracellular infection.
PAIR2 is essential for homologous chromosome synapsis in rice meiosis I
Authors: Nonomura Ken-Ichi , Nakano Mutsuko , Eiguchi Mitsugu , Suzuki Tadzunu , Kurata Nori
Published: January 2006

The PAIR2 gene is required for homologous chromosome synapsis at meiosis I in rice (Oryza sativa L.) and encodes a HORMA-domain protein that is homologous to Saccharomyces cerevisiae HOP1 and Arabidopsis ASY1. Immunocytological and electron microscopic analyses indicate that PAIR2 proteins associate with axial elements (AEs) at leptotene and zygotene, and is removed from the AEs of arm regions when homologous chromosomes have been synapsed. Immunocytology against a centromeric histone H3 variant revealed that PAIR2 remains at centromeres until diakinesis, by which time the homologous centromeres had already been synapsed. However, neither precocious segregation of sister chromatids nor kinetochore dysfunction is observed, and AEs are normally assembled in the mutant. In the pair2-null mutant, homologous chromosome synapsis is completely eliminated. This study provides the first description of AE-associated protein in monocot plants and indicates that PAIR2 plays an essential role in promoting homologous chromosome synapsis. However, PAIR2 does not play a role in AE formation, sister chromatid cohesion at centromeres or kinetochore assembly in meiosis I of rice.
Suppressors of cytokine signaling (SOCS) 1 and SOCS3 interact with and modulate fibroblast growth factor receptor signaling
Authors: Ben-Zvi Tal , Yayon Avner , Gertler Arieh , Monsonego-Ornan Efrat
Published: January 2006

Fibroblast growth factor receptor (FGFR) signaling is transduced by the mitogen-activated protein kinase (MAPK) cascade and the signal transducers and activators of transcription (STATs). Suppressors of cytokine signaling (SOCS) proteins are expressed in response to cytokine-inducible stimulation of STAT phosphorylation, acting in a negative-feedback mechanism to hinder the activities of these receptors. However, there are no data concerning the role of SOCS proteins in the regulation of fibroblast growth factor receptor (FGFR) signaling. In the present study, we show that activation of FGFR in chondrocytes induces the expression of SOCS1 and SOCS3 mRNA, and that these proteins are constitutively associated with FGFR3, as demonstrated by co-immunoprecipitation studies. Transfection of cells with FGFR3-GFP and SOCS1-CFP revealed their colocalization, clustered prominently in the perinuclear cytosolic part of the cell. The effect of the interaction between FGFR3 and SOCS1 on receptor activity was investigated in a chondrocytic cell line overexpressing SOCS1. In these cells, STAT1 phosphorylation is repressed, MAPK phosphorylation is elevated and prolonged, and FGFR3 downregulation is attenuated. Expression of osteopontin (OPN), which is directly upregulated by FGF in chondrocytes, was stimulated by lower levels of FGF in cells expressing SOCS1 compared with parental cells. Blocking of MAPK phosphorylation by PD98059 decreased OPN expression in both cell types, but this decrease was more marked in cells expressing SOCS1. The presented results suggest a novel interaction between the SOCS1 and SOCS3 proteins and the FGFR3 signaling pathway.
A molecular link A molecular link between Hairless and Pros26.4, a member of the AAA-ATPase subunits of the proteasome 19S regulatory particle inDrosophila
Authors: Müller Dominik , Nagel Anja C. , Maier Dieter , Preiss Anette
Published: January 2006

The proteasome is the major degradation machinery of the cell that regulates multiple cellular processes as diverse as cell cycle, signal transduction and gene expression. Recognition and unfolding of target proteins involves the regulatory cap whose base contains six AAA-ATPases that display reverse chaperone activity. One of them, Rpt2 (also known as S4), has an essential role in gating the degradative central core. We have isolated the orthologous gene Pros26.4 from Drosophila melanogaster as a molecular interaction partner of Hairless. Hairless plays a major role as antagonist of Notch signalling in Drosophila, prompting our interest in the Hairless-Pros26.4 interaction. We find that Pros26.4 negatively regulates Hairless at the genetic and molecular level. Depletion of Pros26.4 by using tissue-specific RNA interference (RNAi) resulted in a specific stabilization of the Hairless protein, but not in stabilization of the intracellular domain of Notch or the effector protein Suppressor of Hairless. Thus, the Hairless-Pros26.4 interaction provides a novel mechanism of positive regulation of Notch signalling.
The Shwachman-Bodian-Diamond syndrome gene encodes an RNA-binding protein that localizes to the pseudopod ofDictyosteliumamoebae during chemotaxis
Authors: Wessels Deborah , Srikantha Thyagarajan , Yi Song , Kuhl Spencer , Aravind L. , Soll David R.
Published: January 2006

The Shwachman-Bodian-Diamond syndrome (SBDS) is an autosomal disorder with multisystem defects. The Shwachman-Bodian-Diamond syndrome gene (SBDS), which contains mutations in a majority of SBDS patients, encodes a protein of unknown function, although it has been strongly implicated in RNA metabolism. There is also some evidence that it interacts with molecules that regulate cytoskeletal organization. Recently, it has been demonstrated by computer-assisted methods that the single behavioral defect of polymorphonuclear leukocytes (PMNs) of SBDS patients is the incapacity to orient correctly in a spatial gradient of chemoattractant. We considered using the social amoeba Dictyostelium discoideum, a model for PMN chemotaxis, an excellent system for elucidating the function of the SBDS protein. We first identified the homolog of SBDS in D. discoideum and found that the amino acids that are altered in human disease were conserved. Given that several proteins involved in chemotactic orientation localize to the pseudopods of cells undergoing chemotaxis, we tested whether the SBDS gene product did the same. We produced an SBDS-GFP chimeric in-frame fusion gene, and generated transformants either with multiple ectopic insertions of the fusion gene or multiple copies of a non-integrated plasmid carrying the fusion gene. In both cases, the SBDS-GFP protein was dispersed equally through the cytoplasm and pseudopods of cells migrating in buffer. However, we observed differential enrichment of SBDS in the pseudopods of cells treated with the chemoattractant cAMP, suggesting that the SBDS protein may play a role in chemotaxis. In light of these results, we discuss how SBDS might function during chemotaxis.
Dystroglycan: from biosynthesis to pathogenesis of human disease
Authors: Barresi Rita , Campbell Kevin P.
Published: January 2006

α- and β-dystroglycan constitute a membrane-spanning complex that connects the extracellular matrix to the cytoskeleton. Although a structural role for dystroglycan had been identified, biochemical and genetic discoveries have recently highlighted the significance of posttranslational processing for dystroglycan function. Glycosylation is the crucial modification that modulates the function of dystroglycan as a receptor for extracellular binding partners. It has become clear that perturbation of dystroglycan glycosylation is the central event in the pathogenesis of several complex disorders, and recent advances suggest that glycosylation could be modulated to ameliorate the pathological features. Our increased understanding of the mechanisms of interaction of dystroglycan with its ligands has become an essential tool in deciphering the biological processes related to the human diseases in which the proteins are implicated.
Of Myc and Mnt
Authors: Hooker C. William , Hurlin Peter J.
Published: January 2006

Deregulation of Myc expression is a common feature in cancer and leads to tumor formation in experimental model systems. There are several potential barriers that Myc must overcome in order to promote tumorigenesis, including its propensity to sensitize many cell types to apoptotic cell death. Myc activities appear also to be constrained and fine-tuned by a set of proteins that include the Mxd (formerly named Mad) family and the related protein Mnt. Like Myc-family proteins, Mxd and Mnt proteins use Max as a cofactor for DNA binding. But Mnt-Max and Mxd-Max complexes are transcriptional repressors and can antagonize the transcriptional activation function of Myc-Max. Studies examining the relationship between Myc, Mxd and Mnt proteins suggest that whereas Mnt plays a general role as a Myc antagonist, Mxd proteins have more specialized roles as Myc antagonist that is probably related to their more restricted expression patterns. The interplay between these proteins is postulated to fine-tune Myc activity for cell-cycle entry and exit, proliferation rate and apoptosis.
Three design experiments for computer-supported collaborative design
Authors: Seitamaa-Hakkarainen Pirita , Lahti Henna , Hakkarainen Kai
Published: January 2006

The purpose of the present article is to examine how virtual design studio environments can be used to aid collaborative designing and to describe some of our experiences in supporting collaborative design with such environments. The authors will introduce three design projects. These
were projects, respectively, for designing clothes for premature babies; conference bags; and tactile books for visually impaired children: they constitute a continuum in terms of being design experiments, each of which highlights certain perspectives on the virtual design process. Our approach,
in which the first author was acting as a teacher in each project, made it possible to address current problems faced in the field of virtual designing. The purpose of our design experiments is set up, foster, and investigate an iterative design process, in which previous observations and
lessons can be applied to the enhancement of educational settings and practices. The authors examined how participants create shared design ideas, to what extent users can be involved in the design process (participatory designing), and how expert knowledge is utilized. According to our experiments,
the progressive inquiry model can fruitfully be applied to collaborative designing to facilitate participants' interaction processes of developing design ideas and sharing their expertise through the virtual design studio.
Employability issues for fine art educators
Authors: Harbour Sophie
Published: January 2006

The aim of this article is to discuss the current challenges facing higher education in terms of graduate employment, with a particular focus on the issues affecting higher education institutions offering fine art programmes of study. The government agenda on widening participation
in higher education has meant that graduate employment has now become a fiercely disputed topic across the subject disciplines. More specifically, fine art has its own very particular set of issues in relation to the employment agenda and what this article aims to debate is whether institutions
offering fine art courses are currently doing enough to support their graduates in understanding what their possible employment routes may be.
Implementing work-based learning within masters' courses in design: A research evaluation of curriculum
Authors: Marsden Ken , Luczkowski Jeannette
Published: January 2006

This article has been developed from an internally funded educational research project undertaken to address the needs of a specific institution, namely Southampton Institute. However, the key issues described, which include learning contracts, information and communications technologies
(ICT), accreditation of prior experiential learning (AP[E]L) and placement schemes, have relevance to other higher education institutions (HEIs) associated with introducing work-based learning (WBL) within the design curriculum at postgraduate level. The article includes a review of recent
government documents, reports, websites and conference papers. The article not only locates the importance of design as a key player within the creative industries but also suggests how the postgraduate design curriculum can provide a viable opportunity for developing important employability
skills. Finally, the article discusses the background to, and definitions of, workbased learning, and concludes with an analysis of some the challenges and benefits involved with developing an effective and alternative mode of learning.
Book Reviews
Authors: Thomas Barbara E. , Jackson Barry
Published: January 2006

Managing Educational Development Projects: Effective Management for Maximum Impact
, Carole Baume, Paul Martin and Mantz Yorke (eds), (2003). London: Kogan Page, 224 pp., ISBN 07494 3882 7, Paperback, £22.50

Teaching for Quality Learning at University
,
John Biggs, (2003), 2nd edition. Buckingham: SRHE and Open University Press, 304pp, ISBN 0-335-21168-2 (pbk), £25
Stimulating critical thinking in the theoretically timid: the role and value of oral history assignments within an interdisciplinary context
Authors: Biddle-Perry Geraldine
Published: January 2006

The Cultural Studies Department at London College of Fashion introduced an Oral History unit in the Summer Term 2003, offering students the opportunity to engage in primary research by conducting oral history interviews, and develop critical arguments around their interpretation and
analysis. The unit aimed to contribute to a more culturally diverse curriculum, and enhance the learning experience and outcomes of participating students by offering a tangible demonstration of both the relevance of such research to the study of fashion and dress, and of the students' own
contribution to its furtherance. This article reflects on this experience; suggests some of the ways in which oral history assignments might stimulate critical thinking and independent research; explores how oral history methodology can be situated in relation to an interdisciplinary concept
of ‘research’; outlines how a dialogical approach to theory and practice might address student approaches to research and critical thinking in an interdisciplinary context.
Sutureless Skin Closure for Cleft Lip Repair
Authors: Mourougayan V.
Published: January 2006

Objective:

To study the quality of scars following the use of butyl cyanoacrylate to close the skin during cleft lip repair.

Design:

Nonrandomized prospective study.

Setting:

Tertiary care hospital.

Patients:

Patients (n = 104) with cleft lip and palate in combination of various degrees of cleft with the age group ranging from 3 months to 5 years.

Interventions:

Use of butyl cyanoacrylate to close the skin during cleft lip repair after inserting dermal stitches with delayed absorbable sutures.

Results:

None of the 104 patients required revision of the vertical scar, which was excellent in nature. No patients had complications such as wound infection, dehiscence, nasal obstruction, or eyelid adhesion.

Conclusions:

Quality of the scar following the closure of skin of cleft lip repair using butyl cyanoacrylate was considered excellent.
Linking lipids, Alzheimer's and LXRs?
Authors: Patel Nilay V. , Forman Barry Marc
Published: January 2006

Deposition of the β-amyloid (Aβ) peptide is thought to underlie development of Alzheimer's disease (AD). This pathological linkage has spurred considerable interest in therapeutic strategies to reduce Aβ production. It is becoming increasingly clear that altered cholesterol homeostasis can modulate Aβ production and/or accumulation. In this review, we discuss the molecular pathology of AD, the cholesterol connection and recent data suggesting that the oxysterol receptor, liver X receptor LXR (NR1H2 and NR1H3), may modulate these events.
Single-step purification of full-length human androgen receptor
Authors: Juzumiene Dalia , Chang Ching-yi , Fan Daju , Hartney Tanya , Norris John D. , McDonnell Donald P.
Published: January 2006

The full-length human androgen receptor with an N-terminal biotin acceptor peptide tag was overexpressed in Spodoptera frugiperda cells in the presence of 1 μM dihydrotestosterone. Site-specific biotinylation of BAP was achieved in vivo by co-expression of E. coli biotin holoenzyme synthetase. The androgen receptor was purified by single-step affinity chromatography using Streptavidin Mutein Matrix under native conditions. The resultant protein was active, stable, 95% homogeneous, and we obtained sufficient yield for use in functional and structural studies.
Detection of designer steroids
Authors: Yuan Xiaohui , Forman Barry Marc
Published: January 2006

Illicit use of performance-enhancing steroids has proliferated among a wide range of professional and amateur athletes. This problem has attracted broad public attention and has led the United States Congress to draft legislation that proposes frequent testing of athletes. However, current testing protocols are inadequate as athletes can evade detection by using novel steroids that are unknown to authorities. We have developed a strategy that overcomes this limitation by virtue of its ability to detect “designer steroids” without prior knowledge of their existence.
Corepressors: Custom Tailoring and Alterations While you Wait
Authors: Goodson Michael , Jonas Brian A. , Privalsky Martin A.
Published: January 2006

A diverse cadre of metazoan transcription factors mediate repression by recruiting protein complexes containing the SMRT (silencing mediator of retinoid and thyroid hormone receptor) or N-CoR (nuclear receptor corepressor) corepressors. SMRT and N-CoR nucleate the assembly of still larger corepressor complexes that perform the specific molecular incantations necessary to confer transcriptional repression. Although SMRT and N-CoR are paralogs and possess similar molecular architectures and mechanistic strategies, they nonetheless exhibit distinct molecular and biological properties. It is now clear that the functions of both SMRT and N-CoR are further diversified through alternative mRNA splicing, yielding a series of corepressor protein variants that participate in distinctive transcription factor partnerships and display distinguishable repression properties. This review will discuss what is known about the structure and actions of SMRT, N-CoR, and their splicing variants, and how alternative splicing may allow the functions of these corepressors to be adapted and tailored to different cells and to different developmental stages.
Chaperoning steroid hormone signaling via reversible acetylation
Authors: Kovacs Jeffrey J. , Cohen Todd J. , Yao Tso-Pang
Published: January 2006

Glucocorticoid receptor (GR) and related steroid hormone receptors are ligand-dependent transcription factors whose regulation is critical for both homeostasis and diseases. The structural maturation of the GR has been shown to require the Hsp90 molecular chaperone complex. Evidence indicates that Hsp90-dependent maturation is critical for GR ligand binding capacity and activity. While the role for Hsp90 in GR function is well established, the regulation of this process is not well understood. Here we discuss a recent finding that identifies reversible protein acetylation controlled by the deacetylase HDAC6 as a novel mechanism that regulates Hsp90-dependent GR maturation. We will also speculate on the implications of this finding in steroid hormone signaling, oncogenic transformation and its potential therapeutic utility.
Overview of Anti‐Infective Drug Development
Authors: Barrett John F.
Published: January 2006

The identification and clinical development of an antibiotic as a new chemical entity (NCE) can take up to a decade to complete. The goal of this effort is to identify agents that inhibit and/or kill pathogenic bacteria. Outlined in this unit is a series of key “strategic protocols” utilized for drug development in this area. Included are the identification of the target and the hit/lead, as well as lead optimization for identifying a clinical candidate. The clinical development of a new antimicrobial agent can take 5 to 7 years to complete, depending on the clinical plan. This unit is designed to provide an overview of key aspects of antibacterial drug development and provide an introduction for subsequent units in this chapter that provide more detailed protocols for identifying and testing antimicrobial drugs.
Overview of Antibacterial Target Selection
Authors: Pucci Michael J.
Published: January 2006

Research in microbial genomics has yielded a vast amount of DNA sequence data and a number of new or improved tools for defining the bacterial genome. These findings have dramatically increased the number of potential antibacterial targets, particularly enzymatic sites, and have greatly enhanced their characterization.Potential targets are prioritized according to necessity for survival (essentiality), spectrum, and selectivity using a combination of bioinformatic analyses and experimental results. Experimental methods such as mutagenesis and conditional expression techniques are used to assess essentiality in vitro or virulence in vivo in animal hosts.
Basic Microbiological Techniques Used in Antibacterial Drug Discovery
Authors: Motyl Mary , Dorso Karen , Barrett John , Giacobbe Robert
Published: January 2006

In vitro assessment of activity is crucial to the development of antibacterial agents. Several basic clinical microbiology procedures for this evaluation are provided in this unit, including determination of the minimum inhibitor concentration (MIC), kill curves, and synergy testing. These techniques yield information on in vitro efficacy, cidal‐versus‐static activity, and the potential for synergy with other agents.
Primary Rodent Infection Models for Testing Antibacterial Compound Efficacy In Vivo
Authors: Marra Andrea , Girard Dennis
Published: January 2006

This unit describes three primary screening models for evaluating antibacterial efficacy. Included are systemic bacterial infection (peritonitis), pulmonary infection, also known as respiratory tract infection or RTI, and thigh lesion. All of these infection models can be performed in inexpensive, outbred mice and, as such, offer the advantage of being compound‐sparing while allowing the testing of sufficient numbers to obtain statistically significant results early in the drug development process.
Nucleobase Protection with Allyloxycarbonyl
Authors: Hyodo Mamoru , Hayakawa Yoshihiro
Published: January 2006

This unit describes protocols for preparation of N‐allyloxycarbonyl‐protected 5′‐O‐(4,4′‐dimethoxytrityl)‐2′‐deoxyribonucleosides and 2′‐O‐(tert‐butyldimethylsilyl)‐5′‐O‐(4,4′‐dimethoxytrityl)ribonucleosides. These provide useful building blocks not only for synthesis of natural oligonucleotides but also for artificial analogs with chemically sensitive (particularly, base‐labile) modified nucleoside bases or internucleotide linkages. These protected nucleosides are stable to conditions used for conversion to the corresponding nucleoside phosphoramidites and subsequent oligonucleotide synthesis, and the N‐allyloxycarbonyl protecting group can be easily and cleanly removed by an organopalladium‐catalyzed reaction under mild, nearly neutral conditions.
Isolation of Human Monocyte Populations
Authors: Wahl Larry M. , Wahl Sharon M. , Smythies Lesley E. , Smith Phillip D.
Published: January 2006

This unit describes the isolation of monocytes from lymphocytes by adherence, gradient sedimentation on colloidal silica particles, and flow cytometry. Because the first two methods can result in cell activation (induction of gene expression or protein secretion), and the third is technically difficult, a fourth protocol is presented which describes counterflow centrifugal elutriation. This latter procedure can be used to isolate large numbers of purified, nonactivated monocytes.
Isolation and Purification of Human Intestinal Macrophages
Authors: Smythies Lesley E. , Wahl Larry M. , Smith Philip D.
Published: January 2006

The gastrointestinal mucosa contained within the lamina propria is the largest reservoir of macrophages in the human body. The isolation and study of this population of cells is important for understanding host defense and the pathogenesis of inflammation in the gastrointestinal mucosa. This unit describes methods that can be used to isolate and purify intestinal macrophages. Sources of intestinal tissue that can be used for this isolation include human subjects undergoing gastrojejunostomy for obesity, organ‐transplantation donors, or the noninflamed margin of resected segments of small intestine from subjects undergoing resection for surgically indicated reasons.
Isolation of Lipid Droplets from Cells by Density Gradient Centrifugation
Authors: Brasaemle Dawn L. , Wolins Nathan E.
Published: January 2006

Lipid droplets are organelles found in most mammalian cells, as well as various plant tissues and yeast. They are composed of a core of neutral lipids surrounded by a membrane monolayer of phospholipids and cholesterol into which specific proteins are embedded. This unit provides protocols for isolating lipid droplets from mammalian cells by discontinuous density gradient centrifugation.
Isolation of Zymogen Granules from Rat Pancreas
Authors: Rindler Michael J.
Published: January 2006

This unit describes methods for preparing zymogen granules from rat pancreas. Zymogen granules are storage organelles in pancreatic acinar cells containing digestive enzymes that are released into the pancreatic duct. The protocols in this unit take advantage of the large size (up to 1 µm diameter) and high density (>1.20 g/cm3 on sucrose gradients) of the granules as compared to other cellular organelles. They use a combination of differential sedimentation and density gradient separation to accomplish the purification. Similar procedures can be used to isolate zymogen granules from mouse pancreas and canine pancreas. A protocol for preparing zymogen granules from dog pancreas is also included.
Analysis of the Cell Cycle Using Xenopus Egg Extracts
Authors: Kornbluth Sally , Yang Jing , Powers Maureen
Published: January 2006

In this unit, Xenopus eggs are isolated from hormonally primed female frogs, and then the extract is treated with cyclohexamide so it remains in interphase of the cell cycle. In the presence of sperm chromatin and ATP, membrane vesicles in the extract fuse to assemble nuclei, making the extract suitable for studies of DNA replication and nuclear transport.
Modeling of a multiannular photocatalytic reactor for perchloroethylene degradation in air
Authors: Imoberdorf Gustavo E. , Cassano Alberto E. , Alfano Orlando M. , Irazoqui Horacio A.
Published: January 2006

The full modeling and simulation of a multiannular photocatalytic reactor requires a thorough physical analysis of all the concurrent phenomena determinant of its performance: momentum and mass transfer in the homogeneous, nonuniform, fluid phases; radiation transfer in the fluid phases and across the flow physical boundaries; and heterogeneous photocatalytic reaction kinetics. In a previous work, an expression of the intrinsic kinetics for the degradation of perchloroethylene (PCE) based on a plausible reaction mechanism was proposed and experimentally validated. In this work, this expression is used in the physical modeling and mathematical simulation of a multiannular, bench‐scale reactor. The reactor shows good effectiveness for the PCE degradation in polluted moist air. A radiation field model was developed to predict the local superficial rate of photon absorption (LSRPA) at each point on the reactor catalytic walls, which is needed to evaluate the local reaction rate. A 2‐D mass balance was developed taking into account the intrinsic kinetics, as well as mass‐transfer rate processes and the LSRPA calculated with the radiation field model equations. Predicted conversions show good agreement with experimental results with a root mean square error < 5.6%. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Titelbild: Self‐Organizing β‐Sheet Lipopeptide Monolayers as Template for the Mineralization of CaCO3 (Angew. Chem. 5/2006)
Authors: Cavalli Silvia , Popescu Daniela C. , Tellers Emily E. , Vos Matthijn R. J. , Pichon Benoît P. , Overhand Mark , Rapaport Hanna , Sommerdijk Nico A. J. M. , Kros Alexander
Published: January 2006

Die Entschlüsselung der Vorgänge bei der Biomineralisierung könnte dem Aufbau organisch‐anorganischer Hybridmaterialien mit besonderen Eigenschaften neue Perspektiven eröffnen. N. Sommerdijk und A. Kros et al. beschreiben in ihrer Zuschrift auf S. 753 ff., wie wichtig das Adaptionsvermögen selbstorganisierter β‐Faltblatt‐Lipopeptidmonoschichten ist, die als Template beim Wachstum anorganischer Calcitphasen wirken. (Titelbildgestaltung: Hugo Simões)
Profiling in vitro drug release from subcutaneous implants: a review of current status and potential implications on drug product development
Authors: Iyer Sunil S. , Barr William H. , Karnes H. Thomas
Published: January 2006

This review presents current methods and strategies for studying the release characteristics of drugs from subcutaneous implant dosage forms. Implants are dosage forms that are subcutaneously placed with the aid of surgery or a hypodermic needle, and are designed to release drugs over a prolonged period of time. In most cases, the objective of a release test is to identify sufficiently discriminatory procedures that in turn would provide data to set meaningful specifications. Additional information obtained from successful in vitro–in vivo correlations (IVIVC) and accelerated drug release tests are extremely useful during drug product development.

Although several workers have employed different methods to monitor drug release from these dosage forms, the use of the compendial Apparatus 4 (flow‐through) device has been recommended in a publication on FIP/AAPS Guidelines for drug release testing of modified release dosage forms. However, most of method development with this device has focused on oral immediate or controlled release dosage forms and little published information is available on implants. Two recent reports on workshops provide useful information on methods to evaluate drug release from controlled‐release parenterals such as implants, including IVIVC and accelerated release testing. Details on such studies, however, are generally not found in the literature; possibly because of the high proprietary value of methodologies for establishing release specifications of implant dosage forms. This article reviews the current status of methodologies used in the investigation of drug release from subcutaneous implants with an emphasis on mechanistic, product development and regulatory perspectives. Copyright © 2006 John Wiley & Sons, Ltd.
Generation of free radicals and electrochemiluminescence from simple aromatic molecules in aqueous solutions
Authors: Ala‐Kleme Timo , Kulmala Sakari , Jiang Qinghong
Published: January 2006

Oxide‐covered aluminium electrodes were used to demonstrate that aromatic compounds, such as the simple derivatives of benzene, can be electrochemically excited at cathodically pulse‐polarized conductor/insulator/electrolyte (C/I/E) tunnel junction electrodes (e.g. oxide‐covered aluminium electrodes). The primary cathodic process at these electrodes was a tunnel emission of hot electrons into an aqueous electrolyte solution. Fluorescence (FL) and electrochemiluminescence (ECL) spectra were compared and the dependence of the electrochemiluminescence on the concentrations of benzene, toluene, phenol, p‐cresol and aniline were measured and detailed mechanisms for the present electrochemiluminescence are proposed. Copyright © 2006 John Wiley & Sons, Ltd.
Study on the redox state dependent γ(CH) vibrational modes of the c‐type heme
Authors: Dörr Sabine , Wolpert Martina , Hellwig Petra
Published: January 2006

Absorbance Fourier transform infrared (FTIR) spectra of model compounds for heme proteins such as protoporphyrin‐IX, hemin, and hematin have been directly compared to the data of electrochemically induced FTIR difference spectra of small c‐type proteins, i.e., microperoxidase‐11, and cytochrome c. A band at 840–830 cm−1 occurring in all studied samples dominated the spectra. The position of this vibrational mode depends on pH and the oxidation state, and could be assigned to the γ(CH) mode of the porphyrin ring. Further features, such as the ring vibrations sensitive for the presence of iron and its oxidation state, are shown in the low‐frequency infrared region between 750 and 650 cm−1. © 2006 Wiley Periodicals, Inc. Biopolymers 82:349–352, 2006

This 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
Large‐amplitude fast motions in double‐stranded DNA driven by solvent thermal fluctuations
Authors: Shih Chia C. , Georghiou Solon
Published: January 2006

The nature of the internal dynamics of double‐stranded DNA in aqueous environment remains to be established. We consider the motions to stem from thermal fluctuations/dissipations of the harmonic modes of beads (bases and sugars) in a cylindrical geometry that are tracked through the stochastic Langevin trajectories; these are characterized by parameters obtained from published data. The present approach has allowed a comparative study of the dynamics for DNA lengths in the range of 20–600 base pairs. For this range, we find that rotational motions about directions parallel to the helix axis (opening, twist) and perpendicular to it (propeller‐twist, roll) contribute significantly to the dynamics. For a 20‐mer at a solvent viscosity of 1 cP, the calculated fluorescence anisotropy profile exhibits a fast decay in the subnanosecond range due to large‐amplitude fluctuations at the mesoscopic level. This feature reproduces the experimental behavior well, and suggests a possible way for the initiation of biological processes: they may be suddenly triggered on this scale through the occurrence of favorable thermal fluctuations. This analysis also reveals that, as is the case for a 20‐mer, the dynamics of longer N‐mers are dominated by internal motions, and are modulated by the viscosity of the solvent, in agreement with our previous experimental observations. Moreover, the model indicates that occurrence of partially concerted rotations of the bases due to thermal fluctuations can possibly be sustained over a DNA length of the order of 100 Å at 1 ns, suggesting a possible mechanism for action‐at‐a‐distance in transcription. © 2006 Wiley Periodicals, Inc. Biopolymers 81: 450–463, 2006

This 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
Towards Polyoxometalate‐Integrated Nanosystems
Authors: Long De‐Liang , Cronin Leroy
Published: January 2006

Polyoxometalates represent a diverse range of molecular clusters with an almost unmatched range of physical properties and the ability to form structures that can bridge several length scales. The new building block principles that have been discovered are beginning to allow the design of complex clusters with desired properties and structures; several structural types and novel physical properties are examined herein. The overall message that is presented throughout is the possibility that polyoxometalate clusters could be excellent candidates to be exploited in the development of functional nanosystems or nanodevices. The concepts that underpin the development of nanoscale devices are discussed briefly, as are the considerable challenges that must be overcome to realise polyoxometalate‐based functional nanosystems.
Manganese‐Substituted Carbonic Anhydrase as a New Peroxidase
Authors: Okrasa Krzysztof , Kazlauskas Romas J.
Published: January 2006

Carbonic anhydrase is a zinc metalloenzyme that catalyzes the hydration of carbon dioxide to bicarbonate. Replacing the active‐site zinc with manganese yielded manganese‐substituted carbonic anhydrase (CA[Mn]), which shows peroxidase activity with a bicarbonate‐dependent mechanism. In the presence of bicarbonate and hydrogen peroxide, (CA[Mn]) catalyzed the efficient oxidation of o‐dianisidine with kcat/KM=1.4×106 m−1 s−1, which is comparable to that for horseradish peroxidase, kcat/KM=57×106 m−1 s−1. CA[Mn] also catalyzed the moderately enantioselective epoxidation of olefins to epoxides (E=5 for p‐chlorostyrene) in the presence of an amino‐alcohol buffer, such as N,N‐bis(2‐hydroxyethyl)‐2‐aminoethanesulfonic acid (BES). This enantioselectivity is similar to that for natural heme‐based peroxidases, but has the advantage that CA[Mn] avoids the formation of aldehyde side products. CA[Mn] degrades during the epoxidation limiting the yield of the epoxidations to <12 %. Replacement of active‐site residues Asn62, His64, Asn67, Gln92, or Thr200 with alanine by site‐directed mutagenesis decreased the enantioselectivity demonstrating that the active site controls the enantioselectivity of the epoxidation.
Synthesis of Polyphosphazene with Pendent Perfluorobutylsulfonylimide Group
Authors: Zhang Zheng‐Bo , Wang Xin‐Zeng , Nie Jin
Published: January 2006

A new polyphosphazene with perfluorobutylsulfonylimide as a pendent group has been prepared. The structure of the polymer and its properties were characterized by 1H NMR, 19F NMR, IR spectra, gel permeation chromatography, and thermogravimetric analysis.
An Efficient Synthesis of New Polyether Dendrimers Based on the A2B Type Monomer from 5‐Hydroxyisophthalic Acid
Authors: Shi Zi‐Fa , Zhou Zhao‐Li , Cao Xiao‐Ping
Published: January 2006

Long chain branched dendrimers 1,2 and 3were easily prepared according to the convergent strategy based on the A2B type monomer from 5‐hydroxyisophthalic acid. These dendrimers have a nucleophilic phenol focal group, which is useful to further chemistry.
Influence of Emulsifiers on the Synthesis of Insulin‐loaded Nanocapsules in Double Emulsion
Authors: Zhu Yin‐Yan , Zhang Gao‐Yong , Hong Xin‐Lin , Dong Jin‐Feng , Xia Bi‐Lai
Published: January 2006

Insulin entrapped nanocapsules to use polylactide (PLA) as the encapsulating material were prepared through a modified water‐in‐oil‐in‐water (W/O/W) emulsification and solvent evaporation method. The average particle size of PLA nanocapsules obtained was decreased to (181.5±8.4) nm, and capably adjusted from 180 to 370 nm by using different types and content of nonionic emulsifiers. The influence of emulsifiers on property of nanocapsules was discussed in detail. The effects of spans and tweens to modify the size of the nanocapsules were different, which can be due to the distribution of the surfactants on the inner interface between the inner water and oil of the double emulsion. The encapsulation efficiency and drug release of nanocapsules were affected obviously by the content and type of emulsifiers.
In situ Chemical Deposition of Polyaniline on Activated Carbon for Electrochemical Capacitors
Authors: Zhou Zhang‐Hua , Cai Nai‐Cai , Zeng Yan , Zhou Yun‐Hong
Published: January 2006

Polyaniline (PA) film was chemically deposited onto the surface of activated carbon (AC) uniformly. Chemical deposition was carried out in 0.1 mol/L aniline plus 0.5 mol/L H2SO4 solution adopting V2O5·nH2O coated on the surface of activated carbon as oxidant. The surface morphologies and structures of the composite materials were characterized by scanning electron microscopy and FT‐IR spectra. The electrochemical properties of the composite material electrodes were studied by cyclic voltammetry and constant current charge/discharge tests in 1 mol/L H2SO4 solutions. The specific capacitance of composite materials was exhibited as high as 237.5 F/g at a current density of 1.0 A/g compared with a value of 120 F/g for pure carbon electrode. Good power characteristic and good stability of composite electrodes were also demonstrated.
Iodine Catalyzed Three‐component Strecker‐type Synthesis of α‐Aminonitriles from Aldehydes, Amines and Tributyltin Cyanide
Authors: Wang Hong‐She , Zhao Li‐Fang , Du Zhi‐Ming
Published: January 2006

A simple and efficient one‐pot method has been developed for the synthesis of α‐aminonitriles from aldehydes, amines and tributyltin cyanide in the presence of a catalytic amount of iodine with high yields. The reactions proceeded smoothly at room temperature via very simple procedure.
β‐Tosylamino and β‐Hydroxyl Substituted α‐Diazocarbonyl Compounds: X‐ray Structure and 1,2‐Migrations under Photochemical Condition
Authors: Ma Ming , Yan Zhao , Zhang Shi‐Wei , Wang Jian‐Bo
Published: January 2006

As a continuation of the investigation on 1,2‐migration of metal carbene and free carbene, two X‐ray structures of β‐substituted α‐diazocarbonyl compounds were obtained. The relationship between the structure and 1,2‐migratory aptitude was discussed and an exploratory photochemical study of the diazo compounds presented.
Two‐photon Dissociation Study of Carbon Disulfide in Acetonitrile at 266 nm
Authors: Fang Hao‐Jie , Zhang Ren‐Xi , Ouyang Bin , Zhu Cheng‐Zhu , Dong Wen‐Bo , Hou Hui‐Qi
Published: January 2006

Using laser flash photolysis/transient absorption technique for the study of two photon photodissociation of carbon disulfide in acetonitrile solution at 266 nm, the transient UV‐Vis absorption spectrum of Rydberg state CS2 (6sσg) within 240–370 nm and subsequent dissociation product CS (α3Π) with the maximum absorption at 260 nm were directly observed. The lifetime of CS (α3Π) in the nitrogen and oxygen saturated solution is also studied in our experiment.
Chemiluminescence of ClO3−‐SO32−‐Rh6G‐SDBS System and Its Application to the Determination of Sulfite
Authors: Chen Xiang‐Lei , Zhao Li‐Xia , Lin Jin‐Ming
Published: January 2006

Based on the micelle synergism mechanism, a chemiluminescence (CL) flow system for the determination of sulfite was described. The CL signal generated from the reaction of chlorate with sulfite in acidic solution was very weak, while the interfusion of sodium dodecylbenzenesulfonate (SDBS) resulted in a highly chemiluminescent intensity. The major goal of this work was to investigate and develop the SDBS micelle synergetic CL system. The mechanism was proposed and proved by spectrometry. The results indicated that the unique structure of SDBS micelles promoted the aggregation of rhodamine 6G (Rh6G) and a much easier energy transfer, leading to a marked shift to red in the CL emission. This CL system was developed for the determination of sulfite and the concentration of sulfite was proportional to the CL intensity in the range of 5.0×10−8–1.0×10−5 mol/L with the detection limit of 1.7×10−8 mol/L (S/N=3). The relative standard deviation was 3.3% for 1.0×10−6 mol/L sulfite solution with eleven repeated measurements. This method was successfully applied to the determination of sulfite in powder sugar.
A Rapid and Convenient Synthetic Route to Novel 1,5‐Benzodiazepine Derivatives of 5‐Methyl‐3‐phenyl‐2‐oxo‐Δ4‐1,3,4‐oxadiazolines from p‐Acetylphenylsydnone and Their Pharmacological Activity
Authors: Kamble Ravindra R. , SUDHA Belagur S.
Published: January 2006

A simple and high yielding method for the integration of 1,5‐benzodiazepines integrated with 5‐methyl‐2‐oxo‐3‐phenyl‐Δ4‐1,3,4‐oxadiazolines in 75%–90% yield by microwave irradiation is devised. Microwave‐accelerated reaction was compared with thermal method. All the compounds were characterized by physical, analytical and spectral (IR, 1H NMR, MS) data. Title compounds were screened for preliminary pharmacological activities.
Resonance Light Scattering Imaging Detection of Single Suprahelical Species of DNA Induced by Porphine‐5,10,15,20‐tetrakis(p‐phenyltrimethylaminium)
Authors: Liu Xi‐Dong , Huang Cheng‐Zhi , Guo Hong‐Ping , Huang Yu‐Ming
Published: January 2006

A resonance light scattering (RLS) imaging method was proposed based on imaging and measuring the RLS features of single suprahelical species of DNA, and its application to DNA assay was also investigated. In acidic medium, porphine‐5,10,15,20‐tetrakis(p‐phenyltrimethylaminium) (PTPTMA), could stack along the molecular surface of DNA with the mode of long‐range assembly to induce the formation of suprahelical species of DNA, resulting in strong RLS signals in the range of 450–510 nm. Under the excitation of 488 nm light beam of argon ion laser source, single suprahelical species could be observed with the aid of a common microscope due to the strong scattered light emitted by the suprahelical species. By capturing the RLS images of the single suprahelical species with a cooled charge coupled device (CCD) camera, and analyzing the RLS data, herein an RLS imaging method of DNA was proposed based on the linear relationship between the counts of suprahelical species in the detection focus plane and the concentration of DNA in nanograms. When 1.8??µmol/L PTPTMA was employed, both calf thymus DNA (ct DNA) and fish sperm DNA (fs DNA) in the range of 25–1100 ng/mL could be detected with the limits of detection lower than 25 ng/mL (3σ). Four synthetic samples were detected satisfactorily with relative standard deviations less than 5.1%.