bluuebunny/crossref_metadata_2025 huggingface dataset:
Homo-Dimeric Spherulin 3a: A Single-Domain Member of the bg-Crystallin Superfamily
Authors: Kretschmar M. , Mayr E.-M. , Jaenicke R.
Published: September 2004

The βγ-crystallin superfamily of eye lens proteins comprises a class of structurally related members with a wide variety of different functions. Common features of these proteins are 1. the Greek-key motif of antiparallel β-sheets, called the crystallin fold, and 2. the high intrinsic long-term stability. Spherulin 3a (S3a), a dormant protein from the spherules of Physarum polycephalum, is the only known single-domain protein within the βγ-crystallin family. Based on sequence homology and ‘domain swapping’, it has been proposed to represent an evolutionary ancestor of present-day eye lens crystallins. Since S3a is highly expressed in spherulating plasmodia of P. polycephalum under a variety of stress conditions, it can be assumed that the protein may serve as a compatible solute in the cytosol of the slime mold. In order to investigate the stability and other physicochemical properties of a single-domain all-β protein, we isolated natural S3a. For the large-scale purification, the recombinant protein was cloned and expressed in Escherichia coli. The detailed spectral and biochemical analysis proved the recombinant protein to be authentic. In its native form, S3a is dimeric. Due to its exposed cysteine residues (Cys4), in the absence of reducing agents intermolecular disulfide cross-linking leads to the formation of higher oligomers. In order to preserve the native quaternary structure without aggregation artifacts in denaturation/renaturation experiments, the Cys4→Ser mutant (S3a C4S) was produced. Both the wild-type protein and its mutant are indistinguishable in their physicochemical properties. At pH 3–4, both proteins form a stable compact intermediate (A-state). Concentration-dependent thermal and chemical denaturation showed that the equilibrium unfolding of S3a obeys the simple two-state model with no significant occurrence of folding intermediates.
Plectin: A Cytolinker by Design
Authors: Steinböck F.A. , Wiche G.
Published: September 2004

Plectin is a cytoskeletal protein of > 500 kDa that forms dumbbell-shaped homodimers comprising a central parallel α-helical coiled coil rod domain flanked by globular domains, thus providing a molecular backbone ideally suited to mediate the protein's interactions with an array of other cytoskeletal elements. Plectin self-associates and interacts with actin and intermediate filament cytoskeleton networks at opposite ends, and it binds at both ends to the hemidesmosomal transmembrane protein integrin beta-4, and likely to other junctional proteins. The central coiled coil rod domain can form bridges over long stretches and serves as a flexible linker between the structurally diverse N-terminal domain and the highly conserved C-terminal domain. Plectin is also a target of p34cdc2kinase that regulates its dissociation from intermediate filaments during mitosis.
Regulation of the Sea Urchin Early H2A Histone Gene Expression Depends on the Modulator Element and on Sequences Located near the 3′ End
Authors: Palla F. , Melfi R. , Gaetano L. Di , Bonura C. , Anello L. , Alessandro C. , Spinelli G.
Published: September 2004

Transcription of the sea urchin early histone genes occurs transiently during early cleavage, reaching the maximum at the morula stage and declining to an undetectable level at the gastrula stage. To identify the regulatory elements responsible for the timing and the levels of transcription of the H2A gene, we used promoter binding studies in nuclear extracts and microinjection of a CAT transgene driven by the early H2A promoter. We found that morula and gastrula nuclear proteins produced indistinguishable DNase I footprint patterns on the H2A promoter. Two sites of interactions, centred on the modulator/enhancer and on the CCAAT box respectively, were detected. Deletion of the modulator or coinjection of an excess of modulator sequences severely affected the expression of two transgenes driven by the enhancer-less and modulator-containing H2A promoter. Finally, a DNA fragment containing 3′ coding and post-H2A spacer sequences, where upon silencing three micrococcal nuclease hypersensitive sites were previously mapped, specifically repressed at the gastrula stage the expression of the transgene driven by the H2A promoter. These results indicate that the modulator is essential for the expression of early H2A gene and that sequences for down-regulation are localized near the 3′ end of the H2A gene.
A Novel Way to Induce Erythroid Progenitor Self Renewal: Cooperation of c-Kit with the Erythropoietin Receptor
Authors: Wessely O. , Bauer A. , Quang C. Tran , Deiner E.-M. , Lindern M. von , Mellitzer G. , Steinlein P. , Ghysdael J. , Beug H.
Published: September 2004

Red blood cells are of vital importance for oxygen transport in vertebrates. Thus, their formation during development and homeostasis requires tight control of both progenitor proliferation and terminal red cell differentiation. Self renewal (i.e. long-term proliferation without differentiation) of committed erythroid progenitors has recently been shown to contribute to this regulation. Avian erythroid progenitors expressing the EGF receptor/c-ErbB (SCF/TGFα progenitors) can be induced to long-term proliferation by the c-ErbB ligand transforming growth factor α and the steroids estradiol and dexamethasone. These progenitors have not yet been described in mammals and their factor requirements are untypical for adult erythroid progenitors. Here we describe a second, distinct type of erythroid progenitor (EpoR progenitors) which can be established from freshly isolated bone marrow and is induced to self renew by ligands relevant for erythropoiesis, i.e. erythropoietin, stem cell factor, the ligand for c-Kit and the glucocorticoid receptor ligand dexamethasone. Limiting dilution cloning indicates that these EpoR progenitors are derived from normal BFU-E/CFU-E. For a detailed study, mEpoR progenitors were generated by retroviral expression of the murine Epo receptor in bone marrow erythroblasts. These progenitors carry out the normal erythroid differentiation program in recombinant differentiation factors only. We show that mEpoR progenitors are more mature than SCF/TGFα progenitors and also do no longer respond to transforming growth factor α and estradiol. In contrast they are now highly sensitive to low levels of thyroid hormone, facilitating their terminal maturation into erythrocytes.
An Unexpected Role for p53 in Augmenting SV40 Large T Antigen-Mediated Tumorigenesis
Authors: Herzig M. , Novatchkova M. , Christofori G.
Published: September 2004

Simian virus 40 large T antigen transforms cells by sequestration and inactivation of the tumor suppressor proteins p53, retinoblastoma gene product (pRb), and the pRb-related proteins p107 and p130. Thus, the absence of functional p53 is expected to promote T antigen-mediated tumorigenesis. However, in a transgenic mouse model of T antigen-mediated β cell carcinogenesis (Rip1Tag2), tumor volumes are significantly diminished when these mice are intercrossed with p53-deficient mice. Whereas the incidence of β tumor cell apoptosis is unaffected, their proliferation rate is reduced in p53-deficient β cell tumors
Cmdr1, a Chicken P-Glycoprotein, Confers Multidrug Resistance and Interacts with Estradiol
Authors: Edelmann H.M.L. , Duchek P. , Rosenthal F.E. , Föger N. , Glackin C. , Kane S.E. , Kuchler K.
Published: September 2004

We have cloned from a chicken intestinal cDNA library Cmdr1, the first avian P-glycoprotein. Cmdr1 is 67% and 69% identical to proteins encoded by the human
Constitutive Expression of Interleukin-1beta (IL-1beta) in Rat Oligodendrocytes
Authors: Blasi F. , Riccio M. , Brogi A. , Strazza M. , Taddei M.L. , Romagnoli S. , Luddi A. , DAngelo R. , Santi S. , Costantino-Ceccarini E. , Melli M.
Published: September 2004

The RT-PCR analysis of RNA from progenitor and differentiated primary rat oligodendrocytes, and from the oligodendrocyte CG-4 cell line, shows the presence of the IL-1β mRNA, the type I IL-1 receptor and the IL-1 receptor accessory protein in these cells.
Yeast Cells Allow High-Level Expression and Formation of Polyomavirus-Like Particles
Authors: Sasnauskas K. , Buzaite O. , Vogel F. , Jandrig B. , Razanskas R. , Staniulis J. , Scherneck S. , Krüger D. H. , Ulrich R.
Published: September 2004

Polyomavirus-derived virus-like particles (VLPs) have been described as potential carriers for encapsidation of nucleic acids in gene therapy. Although VLPs can be generated inE. colior insect cells, the yeast expression system should be advantageous as it is well established for the biotechnological generation of products for human use, especially because they are free of toxins hazardous for humans. We selected the yeastSaccharomyces cerevisiaefor expression of the major capsid protein VP1 of a non-human polyomavirus, the hamster polyomavirus (HaPV). Two entire HaPV VP1- coding sequences, starting with the authentic and a second upstream ATG, respectively, were subcloned and expressed to high levels inSaccharomyces cerevisiae. The expressed VP1 assembled spontaneously into VLPs with a structure resembling that of the native HaPV capsid. Determination of the subcellular localization revealed a nuclear localization of some particles formed by the N-terminally extended VP1, whereas particles formed by the authentic VP1 were found mainly in the cytoplasmic compartment.
Purification and MALDI-MS Characterization of Stressin, a Stress-Associated Glycoprotein
Authors: Lauc G. , Peter-Katalinic J. , Dabelic S. , Flögel M.
Published: September 2004

Glycoconjugates have a whole spectrum of biological roles, from those that appear trivial to those that are crucial. Results accumulated in the past years indicate they might also play an important role in the response to stress, a complex physiological response of the human organism to various threats. We have recently identified stressin, a human serum glycoprotein, which was found to be increased under stress conditions. Here we report the purification of stressin from sera of professional soldiers and partial characterization of its protein and carbohydrate parts using lectin blotting and matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS).

Stressin was purified using a combination of ammonium sulfate precipitation, ion exchange chromatography, preparative gel electrophoresis and reverse-phase HPLC. It was found to be a highly glycosylated protein. Only 21.9 kDa (out of 36.7 kDa) was the protein part, whereas the remaining 40% of the mass originated from N-linked oligosaccharides. The carbohydrate part contained 12 sialic acids moieties, nearly 90% of which were lost due to post-source decay in the field-free tube.

Tryptic fragments were produced from glycosylated and deglycosylated stressin, separated by reverse-phase HPLC and their exact molecular masses were determined using MALDI-MS. Comparison with tryptic maps of other proteins in computer databases indicated that stressin does not correspond to any already described protein.
Trypsin from Pacifastacus leninsculus Hepatopancreas: Purification and cDNA Cloning of the Synthesized Zymogen
Authors: Hernández-Cortés P. , Cerenius L. , García-Carreño F. , Söderhäll K.
Published: September 2004

Trypsin was purified from crayfish,Pacifastacus leniusculus, hepatopancreas, and the gene that encoded this enzyme was cloned from a hepatopancreas cDNA library. Crayfish trypsin is synthesized as a zymogen according to the sequence of the putative precursor peptide. The authenticity of the trypsinogen is supported by the deduced amino acid sequence and confirmed by the N-terminal amino acid sequence of the mature protein. The enzyme has features characteristic of a trypsin, such as a specific binding pocket. Sequence comparison shows that crayfish trypsin is similar to those of other species, with the exception that six cysteine residues present in vertebrates are missing. Some structural characteristics, such as the length of the signal peptide and a calcium binding site, are similar to bacterial trypsin.
Molecular Mimicry between a Monoclonal Antibody and One Subunit of Crotoxin, a Heterodimeric Phospholipase A2 Neurotoxin
Authors: Choumet V. , Lafaye P. , Demangel C. , Bon C. , Mazié J.-C.
Published: September 2004

Crotoxin is a heterodimeric phospholipase A2neurotoxin formed by the non-covalent association of an acidic and non-toxic subunit, CA, and a basic and weakly toxic phospholipase A2, CB. The two subunits behave in a synergistic manner. CA enhances the lethal potency of CB by increasing its selectivity of action. The mAb A-56.36, directed against the non-toxic subunit CA, was previously shown to neutralize crotoxin toxicity by dissociating the crotoxin complex. In the present report, a polypeptide sequence similarity was observed between some CDRs of mAb A-56.36 and two regions of CB (pos. 60–80 and 95–110). Phage displayed peptides corresponding to VH2 and VH3 of mAb A-56.36 and to their homologous sequences in CB bind CA to different extents. This observation shows that mAb A-56.36 interacts with a region of CA involved in its interaction with CB, therefore mimicking the binding of CB to CA. A similar approach was used to determine the regions of ammodytoxin A and of agkistrodotoxin, two phospholipase A2neurotoxins similar to CB, which are involved in the formation of heterocomplexes with CA. The analysis of these data contributes to the determination of stretches of amino acids which could constitute the paratope of mAb A-56.36, as well as the region of association of CB with CA in crotoxin.
Superlinear Population Encoding of Dynamic Hand Trajectory in Primary Motor Cortex
Authors: Paninski Liam , Shoham Shy , Fellows Matthew R. , Hatsopoulos Nicholas G. , Donoghue John P.
Published: September 2004

Neural activity in primary motor cortex (MI) is known to correlate with hand position and velocity. Previous descriptions of this tuning have (1) been linear in position or velocity, (2) depended only instantaneously on these signals, and/or (3) not incorporated the effects of interneuronal dependencies on firing rate. We show here that many MI cells encode a superlinear function of the full time-varying hand trajectory. Approximately 20% of MI cells carry information in the hand trajectory beyond just the position, velocity, and acceleration at a single time lag. Moreover, approximately one-third of MI cells encode the trajectory in a significantly superlinear manner; as one consequence, even small position changes can dramatically modulate the gain of the velocity tuning of MI cells, in agreement with recent psychophysical evidence. We introduce a compact nonlinear “preferred trajectory” model that predicts the complex structure of the spatiotemporal tuning functions described in previous work. Finally, observing the activity of neighboring cells in the MI network significantly increases the predictability of the firing rate of a single MI cell; however, we find interneuronal dependencies in MI to be much more locked to external kinematic parameters than those described recently in the hippocampus. Nevertheless, this neighbor activity is approximately as informative as the hand velocity, supporting the view that neural encoding in MI is best understood at a population level.
Abl Tyrosine Kinase Promotes Dendrogenesis by Inducing Actin Cytoskeletal Rearrangements in Cooperation with Rho Family Small GTPases in Hippocampal Neurons
Authors: Jones Shiloh B. , Lu Hope Y. , Lu Qun
Published: September 2004

Nonreceptor tyrosine kinase Abl is an actin-binding protein and a key regulator of neuronal axonal development. Although Abl family kinases also are localized in dendrites and are implicated in postsynaptic functions, it is not clear how Abl kinases regulate dendritic morphogenesis. Using a developing hippocampal culture as a model, we found that the inhibition of Abl kinases by STI571 leads to a remarkable simplification of dendritic branching similar to the phenotype caused by an increased activity of small GTPase RhoA. Time-lapse microscopic imaging reveals a prominent reduction of dendritic branching. In contrast, neurons expressing a constitutively active v-ablconstruct (CA-Abl) show an exuberant microtubule-associated protein 2-positive (MAP2-positive) dendrite outgrowth, suggesting that Abl modulates dendritic growth. Biochemical assays using a glutathioneS-transferase pull-down method to determine GTP-bound active Rho GTPases demonstrate that Abl inhibition increases RhoA activity but has no effect on the activity of Rac1 or Cdc42. At the cellular level the alteration of Abl also changes actin organization consistent with RhoA inhibition. Suppression of the RhoA downstream effector Rho kinase reverses STI571-induced dendritic simplification, demonstrating that activity of the Rho pathway is responsible for the Abl-induced changes in dendrogenesis. Furthermore, CA-Abl-induced neurite outgrowth is blocked by the expression of a constitutively active RhoA construct. The CA-Abl phenotype is not affected by destabilization of microtubules but is reversed partially when actin filaments are stabilized with jasplakinolide. Together, these studies support a critical role for Abl kinases in regulating dendrogenesis by inducing actin cytoskeletal rearrangements in cooperation with Rho GTPases.
Activation of EGL-47, a Gαo-Coupled Receptor, Inhibits Function of Hermaphrodite-Specific Motor Neurons to RegulateCaenorhabditis elegansEgg-Laying Behavior
Authors: Moresco James J. , Koelle Michael R.
Published: September 2004

Caenorhabditis elegansegg-laying behavior is inhibited by neurotransmitter signaling through the neural G-protein Gαoand serves as a model for analyzing Gαosignaling. Mutations that alter egg-laying frequency have identified genes encoding a number of signaling proteins that act with Gαo, but the receptors that activate Gαoremain mostly uncharacterized. To further analyze Gαosignaling, we cloned theegl-47gene, which was identified by two dominant mutations that severely inhibit egg laying.egl-47encodes two orphan G-protein-coupled receptor isoforms, which share all seven transmembrane domains but have different extracellular N termini. Both dominant mutations change the same alanine to valine in the sixth transmembrane domain, resulting in constitutively activated receptors. Deletion of theegl-47gene caused no detectable egg-laying defects, suggesting that EGL-47 functions redundantly, or it inhibits egg laying under specific circumstances as yet unidentified. Using promoter::green fluorescent protein transgenes, we found that EGL-47 is expressed in a number of neurons, including the hermaphrodite-specific neurons (HSNs) that innervate the egg-laying muscles to stimulate contraction. Transgenic expression of constitutively active EGL-47 or constitutively active Gαospecifically in the HSNs was sufficient to inhibit egg-laying behavior. Our results suggest that EGL-47 regulates egg laying by activating Gαoin the HSN motor neurons to inhibit their activity. Because several neurotransmitters act through Gαoto inhibit HSN function, it appears that loss of any one receptor, such as EGL-47, causes only mild defects. Gαoapparently integrates signaling from multiple receptors in the HSNs, including EGL-47, to set the frequency of egg-laying behavior.
CXCR3-Dependent Microglial Recruitment Is Essential for Dendrite Loss after Brain Lesion
Authors: Rappert Angelika , Bechmann Ingo , Pivneva Tatyana , Mahlo Jacqueline , Biber Knut , Nolte Christiane , Kovac Adam D. , Gerard Craig , Boddeke Hendrikus W. G. M. , Nitsch Robert , Kettenmann Helmut
Published: September 2004

Microglia are the resident macrophage population of the CNS and are considered its major immunocompetent elements. They are activated by any type of brain pathology and can migrate to the lesion site. The chemokine CXCL10 is expressed in neurons in response to brain injury and is a signaling candidate for activating microglia and directing them to the lesion site. We recently identified CXCR3, the corresponding receptor for CXCL10, in microglia and demonstrated that this receptor system controls microglial migration. We have now tested the impact of CXCR3 signaling on cellular responses after entorhinal cortex lesion. In wild-type mice, microglia migrate within the first 3 d after lesion into the zone of axonal degeneration, where 8 d after lesion denervated dendrites of interneurons are subsequently lost. In contrast, the recruitment of microglia was impaired in CXCR3 knock-out mice, and, strikingly, denervated distal dendrites were maintained in zones of axonal degeneration. No differences between wild-type and knock-out mice were observed after facial nerve axotomy, as a lesion model for assessing microglial proliferation. This shows that CXCR3 signaling is crucial in microglia recruitment but not proliferation, and this recruitment is an essential element for neuronal reorganization.
Altered Expression of the δ Subunit of the GABAAReceptor in a Mouse Model of Temporal Lobe Epilepsy
Authors: Peng Zechun , Huang Christine S. , Stell Brandon M. , Mody Istvan , Houser Carolyn R.
Published: September 2004

δ Subunit-containing GABAAreceptors are located predominantly at nonsynaptic sites in the dentate gyrus where they may play important roles in controlling neuronal excitability through tonic inhibition and responses to GABA spillover. Immunohistochemical methods were used to determine whether δ subunit expression was altered after pilocarpine-induced status epilepticus in C57BL/6 mice in ways that could increase excitability of the dentate gyrus. In pilocarpine-treated animals, the normal diffuse labeling of the δ subunit in the dentate molecular layer was decreased by 4 d after status epilepticus (latent period) and remained low throughout the period of chronic seizures. In contrast, diffuse labeling of α4 and γ2 subunits, potentially interrelated GABAAreceptor subunits, was increased during the chronic period. Interestingly, δ subunit labeling of many interneurons progressively increased after pilocarpine treatment. Consistent with the observed changes in δ subunit labeling, physiological studies revealed increased excitability in the dentate gyrus of slices obtained from the pilocarpine-treated mice and demonstrated that physiological concentrations of the neurosteroid tetrahydrodeoxycorticosterone were less effective in reducing excitability in the pilocarpine-treated animals than in controls. The findings support the idea that alterations in nonsynaptic δ subunit-containing GABAAreceptors in both principal cells and interneurons could contribute to increased seizure susceptibility in the hippocampal formation in a temporal lobe epilepsy model.
Spinal Dorsal Horn Calcium Channel α2δ-1 Subunit Upregulation Contributes to Peripheral Nerve Injury-Induced Tactile Allodynia
Authors: Li Chun-Ying , Song Yan-Hua , Higuera Emiliano S. , Luo Z. David
Published: September 2004

Peripheral nerve injury induces upregulation of the calcium channel α2δ-1 structural subunit in dorsal root ganglia (DRG) and dorsal spinal cord of spinal nerve-ligated rats with neuropathic pain, suggesting a role of the calcium channel α2δ-1 subunit in central sensitization. To investigate whether spinal dorsal horn α2δ-1 subunit upregulation derives from increased DRG α2δ-1 subunit and plays a causal role in neuropathic pain development, we examined spinal dorsal hornα2δ-1 subunit expression with or without dorsal rhizotomy in spinal nerve-ligated rats and its correlation with tactile allodynia, a neuropathic pain state defined as reduced thresholds to non-noxious tactile stimulation. We also examined the effects of intrathecal α2δ-1 antisense oligonucleotides on α2δ-1 subunit expression and neuropathic allodynia in the nerve-ligated rats. Our data indicated that spinal nerve injury resulted in time-dependentα2δ-1 subunit upregulation in the spinal dorsal horn that correlated temporally with neuropathic allodynia development and maintenance. Dorsal rhizotomy diminished basal level expression and blocked injury-induced expression of the spinal dorsal hornα2δ-1 subunit and reversed injury-induced tactile allodynia. In addition, intrathecal α2δ-1 antisense oligonucleotides blocked injury-induced dorsal horn α2δ-1 subunit upregulation and diminished tactile allodynia. These findings indicate that α2δ-1 subunit basal expression occurs presynaptically and postsynaptically in spinal dorsal horn. Nerve injury induces mainly presynaptic α2δ-1 subunit expression that derives from increased α2δ-1 subunit in injured DRG neurons. Thus, changes in presynaptic α2δ-1 subunit expression contribute to injury-induced spinal neuroplasticity and central sensitization that underlies neuropathic pain development and maintenance.
Expression of Central Glucocorticoid Receptors after Peripheral Nerve Injury Contributes to Neuropathic Pain Behaviors in Rats
Authors: Wang Shuxing , Lim Grewo , Zeng Qing , Sung Backil , Ai Yulan , Guo Gongshe , Yang Liling , Mao Jianren
Published: September 2004

Peripheral glucocorticoid receptors (GRs) play a significant role in the anti-inflammatory effects of glucocorticoids; however, the role of central GRs in nociceptive behaviors after peripheral nerve injury (neuropathic pain behaviors) remains unknown. Here we show that the development of neuropathic pain behaviors (thermal hyperalgesia and mechanical allodynia) induced by chronic constriction nerve injury (CCI) in rats was attenuated by either the GR antagonist RU38486 (4 = 2 > 1 = 0.5 μg) or a GR antisense oligonucleotide administered intrathecally twice daily for postoperative days 1-6. The development of thermal hyperalgesia and mechanical allodynia after CCI also was prevented in adrenalectomized rats, whereas the GR agonist dexamethasone (100 μg/kg) given subcutaneously twice daily for postoperative day 1-6 restored CCI-induced neuropathic pain behaviors in the adrenalectomized rats. Mechanistically, CCI induced a time-dependent and region-specific expression of neuronal GRs primarily within the spinal cord dorsal horn ipsilateral to nerve injury, which showed a time course parallel to that of the development of neuropathic pain behaviors. Moreover, the expression of neuronal GR after CCI was mediated in part through an elevated spinal level of interleukin-6 (IL-6) and protein kinase Cγ (PKCγ), because intrathecal treatment with an IL-6 antiserum, a PKC inhibitor (cheryrithrine), or PKCγ knock-out substantially reduced the expression of neuronal GRs as well as neuropathic pain behaviors after CCI. These findings indicate a central role of neuronal GRs in the mechanisms of neuropathic pain behaviors in rats and suggest a potential role for GR antagonists in clinical management of neuropathic pain.
Metro/Nonmetro Residence, Nonmarital Conception, and Conception Outcomes*
Authors: Albrecht Don E. , Albrecht Carol Mulford
Published: September 2004

Abstract  Two of the most significant changes affecting U.S. society during the 20th century were transformations in family structure and the transition from a nonmetropolitan/farm society to a largely metropolitan society. In this study, classic sociological theory, developed to understand differences between metro and nonmetro society, was employed. Despite contentions that the residence variable is no longer viable, we hypothesized that nonmetro interaction patterns would result in nonmetro residents making more traditional and conservative choices relative to family formation. Analysis of data from the 1995 National Survey of Family Growth provided support for these contentions. Nonmetropolitan women were significantly more likely than metropolitan women to be married at the time of conception. Further, when comparing women who were not married at conception, nonmetro women were significantly more likely than metro women to get married prior to the birth of the child, and were significantly more likely to have the pregnancy result in a live birth.
New! Improved? The Transformation of the Global Agrifood System*
Authors: Busch Lawrence , Bain Carmen
Published: September 2004

Abstract The last decade has witnessed a dramatic rise in global trade in food and agricultural products. While much analysis has focused on the role of the World Trade Organization (WTO) in this process, we argue that other forms of regulation are of far greater consequence. In this paper, we examine changes in the agrifood systemmade possibleby the WTO and we assess the rise of global private standards. We argue that the new global rules, regulations, and institutions implemented by the WTO have facilitated the ability of the private agrifood sector to consolidate and expand internationally. Of particular importance is the growing influence of food retailers as they rapidly become more global and oligopolistic. The article concludes that today it is the private sector, and retailers in particular, together with private standards that are at the center of the transformation of the global agrifood system.
The New Landform's Here! The New Landform's Here! We're Somebody Now!! The Role of Discursive Practices on Place Identity*
Authors: Petrzelka Peggy
Published: September 2004

Abstract  On the border of western Iowa, a new landform—the “Loess Hills,” is being created. While scientific discourse surrounding the landform has been on going for a century, “discovery” of the landform by local residents is a recent occurrence, stimulated by socioeconomic changes resulting from the “farm crisis.” As this case study shows, the initial scientific discourse and claims, as presented in a series of publications, established the uniqueness and rarity of the hills in scientific terms. Through a complexity of discursive practices, this internalized scientific community discussion was brought into broader public conversations. Aspects of the discursive practices have been taken on by residents at the local level and appropriation of the “Loess Hills” name and facts attributed to the landform has resulted in reshaping place identity among rural residents and altering the traditional power position within the region, with “hill people” now becoming “Loess Hills People.”
Continuity and Change in Place Stratification: Spatial Inequality and Middle‐Range Territorial Units*
Authors: Lobao Linda
Published: September 2004

Abstract Sociologists have produced large, well‐known literatures on inequality across geographic territory at two ends of the spatial scale continuum, within the city and across nation‐states. In this paper, I discuss a different scale of focus, subnational stratification processes across middle‐range spatial units, those between the city and nation‐state. While characterizing much contemporary rural sociological research, this approach to spatial inequality does not tend to be seen as a coherent tradition that cross‐cuts substantive areas. First, I discuss why attention to subnational inequality, rural regions, and middle‐range spatial units are important to social science understanding of stratification processes. Second, I provide an overview of contemporary research traditions in rural sociology which, taken together, form a distinct and innovative approach to spatial inequality. Third, I draw from my own work to explain how factors affecting socioeconomic inequalities across middle‐range territorial units may be conceptualized and provide two sets of empirical examples. Finally, I discuss what should be done in terms of furthering rural sociology's regional approach to spatial inequality.
Examining the Association between Hazardous Waste Facilities and Rural “Brain Drain”*
Authors: Hunter Lori M. , Sutton Jeannette
Published: September 2004

Abstract  Rural communities are increasingly being faced with the prospect of accepting facilities characterized as “opportunity‐threat,” such as facilities that generate, treat, store, or otherwise dispose of hazardous wastes. Such facilities may offer economic gains through jobs and tax revenue, although they may also act as environmental “disamenities.” This analysis examines the possibility that the presence of such facilities equates with lower loss of rural human capital, a question as yet unexamined on a national scale within the academic literature. Making use of secondary data from several different sources, we examine the association between age‐ and education‐specific outmigration and 1) the number of hazardous waste facilities, 2) the number of large quantity hazardous waste generators, and 3) the number of hazardous waste landfills and incinerators across rural counties within the 48 contiguous states. Our findings suggest that the presence of hazardous waste facilities does not clearly equate with reductions in rural “brain drain.”
Poverty, Welfare, and the Livelihood Strategies of Nonmetropolitan Single Mothers*
Authors: Brown J. Brian , Lichter Daniel T.
Published: September 2004

Abstract  Using the National Survey of Family Growth, we document nonmetropolitan and metropolitan single mothers' economic livelihood strategies. We have three objectives: (1) examine differences in employment, cohabitation, co‐residence with other adults, and welfare receipt; (2) evaluate how these livelihood strategies are associated with economic well‐being; and (3) identify key metro‐nonmetro differences in the effectiveness of these livelihood strategies in improving the economic well‐being of single mothers. We find surprisingly similar livelihood strategies in nonmetropolitan and metropolitan areas. Employment, cohabitation, and co‐residence are strongly associated with economic well‐being. However, nonmetro single mothers are less likely than metropolitan mothers to benefit economically from full‐time employment. Given our results, “work‐first” policies are likely to be less efficacious in nonmetropolitan areas. Indeed, nonmetropolitan single mothers are often “triply disadvantaged” compared to their metro counterparts; they experience higher rates of poverty, higher barriers to welfare receipt, and lower economic returns from other livelihood strategies.
Engineered Second Harmonic Generation in Photonic‐Crystal Slabs Consisting of Centrosymmetric Materials
Authors: Luo X. , Ishihara T.
Published: September 2004

Second harmonic generation (SHG) based on a quadrupole effect in photonic‐crystal slabs (PCSs) consisting of centrosymmetric materials is presented. The results show that SHG occurs when the pump mode with an asymmetric electromagnetic field distribution is coupled with the eigenmode of the PCS. Theoretical and experimental studies also show that the phase match condition can be achieved without resorting to birefringence or a quasi‐phase‐match condition when two conditions coincide: the fundamental mode and the second harmonic mode are the eigenmodes of the PCS, and they can be excited simultaneously by tuning the dispersion curves so that they cross by changing the thickness of the waveguide layer. The concept of the asymmetry of the electromagnetic field spatial mode can be used in a microcavity to obtain harmonic generation.
Hole Transport in Poly(phenylene vinylene)/Methanofullerene Bulk‐Heterojunction Solar Cells
Authors: Melzer C. , Koop E. J. , Mihailetchi V. D. , Blom P. W. M.
Published: September 2004

A fundamental limitation of the photocurrent of solar cells based on a blend of poly(2‐methoxy‐5‐(3′,7′‐dimethyloctyloxy)‐p‐phenylene vinylene) (MDMO‐PPV) and [6,6]‐phenyl C61‐butyric acid methyl ester (PCBM) is caused by the mobility of the slowest charge‐carrier species, the holes in the MDMO‐PPV. In order to allow the experimentally observed photocurrents electrostatically, a hole mobility of at least 10–8 m2 V–1 s–1 is required, which exceeds the observed hole mobility in pristine MDMO‐PPV by more than two orders of magnitude. However, from space‐charge‐limited conduction, admittance spectroscopy, and transient electroluminescence measurements, we found a hole mobility of 2 × 10–8 m2 V–1 s–1 for the MDMO‐PPV phase in the blend at room temperature. Consequently, the charge‐carrier transport in a MDMO‐PPV:PCBM‐based solar cell is much more balanced than previously assumed, which is a necessary requirement for the reported high fill factors of above 50 %.
Kinetic Study of Homogeneous Alkene Hydrogenation by Model Discrimination
Authors: Greiner Lasse , Ternbach Michel Brik
Published: September 2004

Model discrimination is one of the methods of choice to obtain a valid kinetic description of a catalytic reaction with minimal experimental effort. It allows fast judgement of catalyst behavior and its suitability for process development. Using dynamic experiments and modeling, the kinetics of a homogeneous hydrogenation with cationic rhodium‐PyrPhos {[Rh(PyrPhos)(COD)]BF4} were investigated. A set of three batch experiments allowed the discrimination between 6 models. Qualitative and quantitative descriptions of the kinetic behavior could be derived. Most importantly, evidence for catalyst deactivation was gained.
An Efficient and Improved Method for the Preparation of Nitriles from Primary Amides and Aldoximes†
Authors: Narsaiah A. Venkat , Nagaiah K.
Published: September 2004

The pivaloyl chloride‐pyridine system has been utilized as a novel and efficient reagent for the preparation of nitriles from primary amides and aldoximes. The reaction proceeds smoothly under mild reaction conditions and the products are obtained in excellent yields. This method is applicable to a wide range of substrates including aromatic, heterocyclic and aliphatic species. The dehydration takes place at room temperature in the case of primary amides and dichloromethane at reflux temperature is required for rapid conversion in the case of aldoximes.
Insights into the Cerium Chloride‐Catalyzed Grignard Addition to Esters
Authors: Conlon David A. , Kumke Daniel , Moeder Charles , Hardiman Michelle , Hutson Gerri , Sailer Laura
Published: September 2004

Addition of methylmagnesium chloride to ester 1 in the presence of cerium chloride gave significantly better yields of the tertiary alcohol 2 than the reaction performed in the absence of cerium chloride. The beneficial effect of added cerium chloride is postulated to be due to suppression of the enolization of the ketone intermediate. The use of properly “activated” anhydrous cerium chloride which is proposed to generate a less basic, more nucleophilic species to overcome this undesired reaction was found to be critical. The activated cerium chloride was identified as the known seven‐coordinate THF solvate, [CeCl(μ‐Cl)2(THF)2]n. Inactive crystal forms were also identified and the key parameters for formation of the active form were delineated.
Geminal Bis(sulfoximine)s: Synthesis and Applications in Asymmetric Catalysis
Authors: Reggelin M. , Weinberger H. , Spohr V.
Published: September 2004

A number of C2‐symmetrical geminal bis(sulfoximine)s have been prepared for the first time and used as ligands in boron‐mediated reductions of acetophenone and copper complex‐catalyzed 1,4‐additions of diethylzinc to 2‐cyclohexenone. The copper complex of bis(sulfoximine) 46 was found to be highly active in this type of reaction, furnishing the addition product in nearly quantitative yield even at −90 °C. From the reaction of bis(sulfoximine) 42 with Cu(OTf)2 a copper complex was isolated and characterized by X‐ray structural analysis. A mixture of SES‐Cl and NaN3 in acetonitrile was found to behave like SES‐N3 in FeCl2‐mediated iminations of sulfoxides, affording the corresponding sulfoximines with complete retention of the sulfur configuration.
Mutation screen of the brain derived neurotrophic factor gene (BDNF): Identification of several genetic variants and association studies in patients with obesity, eating disorders, and attention‐deficit/hyperactivity disorder
Authors: Friedel S. , Fontenla Horro F. , Wermter A.K. , Geller F. , Dempfle A. , Reichwald K. , Smidt J. , Brönner G. , Konrad K. , Herpertz‐Dahlmann B. , Warnke A. , Hemminger U. , Linder M. , Kiefl H. , Goldschmidt H.P. , Siegfried W. , Remschmidt H. , Hinney A. , Hebebrand J.
Published: September 2004

Several lines of evidence indicate an involvement of brain derived neurotrophic factor (BDNF) in body weight regulation and activity: heterozygous Bdnf knockout mice (Bdnf+/−) are hyperphagic, obese, and hyperactive; furthermore, central infusion of BDNF leads to severe, dose‐dependent appetite suppression and weight loss in rats. We searched for the role of BDNF variants in obesity, eating disorders, and attention‐deficit/hyperactivity disorder (ADHD). A mutation screen (SSCP and DHPLC) of the translated region of BDNF in 183 extremely obese children and adolescents and 187 underweight students was performed. Additionally, we genotyped two common polymorphisms (rs6265: p.V66M; c.−46C > T) in 118 patients with anorexia nervosa, 80 patients with bulimia nervosa, 88 patients with ADHD, and 96 normal weight controls. Three rare variants (c.5C > T: p.T2I; c.273G > A; c.*137A > G) and the known polymorphism (p.V66M) were identified. A role of the I2 allele in the etiology of obesity cannot be excluded. We found no association between p.V66M or the additionally genotyped variant c.−46C > T and obesity, ADHD or eating disorders. This article contains supplementary material, which may be viewed at the American Journal of Medical Genetics website at http://www.interscience.wiley.com/jpages/0148‐7299:1/suppmat/index.html. © 2004 Wiley‐Liss, Inc.
The keratins and their disorders
Authors: Rugg Elizabeth L. , Leigh Irene M.
Published: September 2004

Diseases caused by mutations in gene encoding keratin intermediate filaments (IF) are characterized by a loss of structural integrity in the cells expressing those keratins in vivo. This is manifested as cell fragility, compensatory epidermal hyperkeratosis, and keratin filament aggregation in some affected tissues. Keratin disorders are a novel molecular category including quite different phenotypes such as epidermolysis bullosa simplex (EBS), bullous congenital ichthyosiform erthroderma (BCIE), pachyonychia congenital (PC), steatocystoma multiplex, ichthyosis bullosa of Siemens (IBS), and white sponge nevus (WSN) of the orogenital mucosa. © 2004 Wiley‐Liss, Inc.
Brainstem pathology in DYT1 primary torsion dystonia
Authors: McNaught Kevin St. P. , Kapustin Alexander , Jackson Tehone , Jengelley Toni‐Ann , JnoBaptiste Ruth , Shashidharan Pullanipally , Perl Daniel P. , Pasik Pedro , Olanow C. Warren
Published: September 2004

DYT1 dystonia is a severe form of young‐onset dystonia caused by a mutation in the gene that encodes for the protein torsinA, which is thought to play a role in protein transport and degradation. We describe, for the first time to our knowledge, perinuclear inclusion bodies in the midbrain reticular formation and periaqueductal gray in four clinically documented and genetically confirmed DYT1 patients but not in controls. The inclusions were located within cholinergic and other neurons in the pedunculopontine nucleus, cuneiform nucleus, and griseum centrale mesencephali and stained positively for ubiquitin, torsinA, and the nuclear envelope protein lamin A/C. No evidence of inclusion body formation was detected in the substantia nigra pars compacta, striatum, hippocampus, or selected regions of the cerebral cortex. We also noted tau/ubiquitin‐immunoreactive aggregates in pigmented neurons of the substantia nigra pars compacta and locus coeruleus in all four DYT1 dystonia cases, but not in controls. This study supports the notion that DYT1 dystonia is associated with impaired protein handling and the nuclear envelope. The role of the pedunculopontine and cuneiform nuclei, and related brainstem other involved brainstem structures in mediating motor activity and muscle tone also suggest that alterations in these structures, in mediating motor activity and controlling muscle tone suggests that alterations in these structures could underlie the pathophysiology of DYT1 dystonia. Ann Neurol 2004
Crystallographic report: [Diaqua bis(2,2′‐bipyridine)(µ‐naphthalene‐1,4,5,8‐tetracarboxylato)]dizinc(II) tetrahydrate
Authors: Zhao Xiao‐Jun , Tao Jun
Published: September 2004

The title complex features a two‐dimensional polymeric structure owing to the presence of µ4‐bridging naphthalene‐1,4,5,8‐tetracarboxylate ligands. The trigonal bipyramidal coordination geometry for zinc is completed by a chelating 2,2′‐bipyridine and a water molecule. Copyright © 2004 John Wiley & Sons, Ltd.
Crystallographic report: Diphenyltin(IV) N‐salicylidenevalinate
Authors: Yin Han Dong , Wang Qi Bao
Published: September 2004

The title compound, {Ph2Sn[2‐OC6H4CHNCHCH(CH3)2COO]}, is a five‐coordinated monomer with trigonal bipyramidal tin and with the axial positions occupied by oxygen atoms derived from the tridentate ligand. Copyright © 2004 John Wiley & Sons, Ltd.
Modeling aerobic carbon oxidation and storage by integrating respirometric, titrimetric, and off‐gas CO2 measurements
Authors: Pratt Steven , Yuan Zhiguo , Keller Jurg
Published: September 2004

A method for detailed investigation of aerobic carbon degradation processes by microorganisms is presented. The method relies on an integrated use of the respirometric, titrimetric, and off‐gas CO2 measurements. The oxygen uptake rate (OUR), hydrogen ion production rate (HPR), and the carbon dioxide transfer rate (CTR) resulting from the biological as well as physicochemical processes, coupled with a metabolic model characterizing both the growth and carbon storage processes, enables the comprehensive study of the carbon degradation processes. The method allows the formation of carbon storage products and the biomass growth rates to be estimated without requiring any off‐line biomass or liquid‐phase measurements, although the practical identifiability of the system could be improved with additional measurements. Furthermore, the combined yield for biomass growth and carbon storage is identifiable, along with the affinity constant with respect to the carbon substrate. However, the individual yields for growth and carbon storage are not identifiable without further knowledge about the metabolic pathways employed by the microorganisms in the carbon conversion. This is true even when more process variables are measured. The method is applied to the aerobic carbon substrate degradation by a full‐scale sludge using acetate as an example carbon source. The sludge was able to quickly take up the substrate and store it as poly‐β‐hydroxybutyrate (PHB). The PHB formation rate was a few times faster than the biomass growth rate, which was confirmed by off‐line liquid‐ and solid‐phase analysis. The estimated combined yield for biomass growth and carbon storage compared closely to that determined from the theoretical yields reported in literature based on thermodynamics. This suggests that the theoretical yields may be used as default parameters for modeling purposes. © 2004 Wiley Periodicals, Inc.
Stochastic modeling of the phase‐variable pap operon regulation in uropathogenic Escherichia coli
Authors: Jarboe Laura R. , Beckwith David , Liao James C.
Published: September 2004

Regulation of the pap operon in uropathogenic Escherichia coli is phase variable. This phase variation arises from competition between regulatory proteins at two sites within the regulatory region, GATCdist and GATCprox. We have used the available literature data to design a stochastic model of the molecular interactions of pap regulation and expression during growth in a non‐glucose environment at 37°C. The resulting wild‐type model is consistent with reported data. The wild‐type model served as a basis for two “in silico” mutant models for investigating the role of key regulatory components, the GATCdist binding site and the PapI interaction with Lrp at the GATCprox site. Our results show that competition at GATCdist is required for phase variation, as previously reported. However, our results suggest that removal of competition at GATCdist does not affect initial state dependence. Additionally, the PapI involvement in Lrp translocation from GATCprox to GATCdist is required for the initial state dependence but not for phase variation. Our results also predict that pap expression is maximized at low growth rates and minimized at high growth rates. These predictions provide a basis for further experimental investigation. © 2004 Wiley Periodicals, Inc.