bluuebunny/crossref_metadata_2025 huggingface dataset:
PMX464, a thiol‐reactive quinol and putative thioredoxin inhibitor, inhibits NF‐κB‐dependent proinflammatory activation of alveolar epithelial cells
Authors: Callister M E , Pinhu L , Catley M C , Westwell A D , Newton R , Leaver S K , Quinlan G J , Evans T W , Griffiths M J , Burke‐Gaffney A
Published: June 2008

Background and purpose:

Subtle changes in the intracellular reduction–oxidation (redox) state can modulate nuclear factor‐κB (NF‐κB) activity. Thioredoxin‐1 (Trx) is a small, ubiquitous, redox‐active thiol (‐SH) protein that, with thioredoxin reductase‐1 (TrxR), modifies the redox status of NF‐κB pathway components. PMX464 is a novel thiol‐reactive quinol thought to inhibit the Trx/TrxR system. The aim of this work was to investigate whether PMX464 inhibited NF‐κB‐mediated proinflammatory activation of human type II alveolar epithelial cells (A549).

Experimental approach:

Intercellular adhesion molecule‐1 (ICAM‐1), granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) and CXCL8, NF‐κB DNA binding, nuclear translocation of NF‐κB p65 subunit, IκBα degradation, IκB phosphorylation and IκB kinase (IKK) activity were assessed in A549 cells stimulated with IL‐1β with or without PMX464 pretreatment. Effects of PMX464 on ICAM‐1 expression in human lung microvascular endothelial cells (HLMVEC) were also investigated. For comparison, selected measurements (ICAM‐1 and IκB‐α phospho‐IκB‐α) were made on A549 cells after RNA interference‐mediated silencing (siRNA) of Trx.

Key results:

PMX464 reduced ICAM‐1, GM‐CSF and CXCL8 expression in IL‐1β‐stimulated A549 cells and ICAM‐1 in HLMVEC. PMX464 inhibited IL‐1β‐induced NF‐κB DNA binding, nuclear translocation of NF‐κB p65 subunit and factors involved in NF‐κB activation; specifically, IκBα degradation, IκB phosphorylation and IκB kinase (IKK) activity in A549. By contrast, Trx siRNA did not alter ICAM‐1 expression or IκBα degradation/phosphorylation in IL‐1β‐stimulated A549 cells.

Conclusion and implications:

PMX464 inhibits a proinflammatory response in A549 cells targeting the NFκB pathway above IKK. The lack of effect with Trx siRNA suggests that PMX464 acts on thiol proteins, in addition to Trx, to elicit anti‐inflammatory responses in lung epithelial cells.

British Journal of Pharmacology (2008) 155, 661–672; doi:fn1; published online 30 June 2008
Cancer and the blood–brain barrier: ‘Trojan horses’ for courses?
Authors: Mazza M , Uchegbu I F , Schätzlein A G
Published: June 2008

The blood–brain barrier (BBB) limits the bioavailability of most bioactive molecules and drugs in the CNS, leaving clinicians with only a few options for pharmacotherapy. In this issue Regina et al. demonstrate that a ‘Trojan horse’ drug conjugate, acting as a substrate of a physiological BBB receptor that facilitates transcytosis, significantly improves drug transport into the CNS. Specifically, the low‐density lipoprotein receptor‐related protein (LRP) is used to carry a conjugate of paclitaxel and Angiopep‐2, an aprotinin‐derived peptide, across the BBB. Interestingly, in its conjugated form paclitaxel circumvents the efflux pumps at the BBB but still retains its activity against microtubules. Importantly, the authors were able to demonstrate improved therapeutic efficacy of this approach in orthotopic models of primary and metastatic brain cancer. This proof‐of‐principle study thus represents a milestone for drug delivery across the BBB but also a starting point for studies exploring wider applicability and potential limitations of the approach.

British Journal of Pharmacology (2008) 155, 149–151; doi:fn1; published online 30 June 2008
Use of Complementary and Alternative Therapies by Overweight and Obese Adults
Authors: Bertisch Suzanne M. , Wee Christina C. , McCarthy Ellen P.
Published: June 2008

Objective: Obesity is associated with higher health‐care costs due, in part, to higher use of traditional health care. Few data are available on the relationship between obesity and the use of complementary and alternative medicine (CAM).

Methods and Procedures: We analyzed data on CAM use from the 2002 National Health Interview Survey (NHIS) Alternative Medicine Supplement (n = 31,044). We compared the use of CAM overall, within the past 12 months, between normal weight (BMI from 18 to <25), overweight (from 25 to <30), mildly obese (from 30 to <35), moderately obese (from 35 to <40), and extremely obese (>40) adults. For the primary analysis, our multivariable model was adjusted for sociodemographic factors, insurance status, medical conditions, and health behaviors. We performed additional analyses to explore the association of BMI and the use of seven CAM modalities.

Results: We found that adults with obesity have lower prevalence of use of yoga therapy, and similar prevalence of use of several CAM modalities, including relaxation techniques, natural herbs, massage, chiropractic medicine, tai chi, and acupuncture, compared to normal‐weight individuals. After adjustment for sociodemographic factors, insurance status, medical conditions, and health behaviors, adults with obesity were generally less likely to use most individual CAM modalities, although the magnitude of these differences were quite modest in many cases.

Discussion: Even though adults with obesity have a greater illness burden and higher utilization of traditional medical care, adults with higher BMIs were no more likely to use each of the individual CAM therapies studied. Additional research is needed to improve our understanding of CAM use by adults with obesity.
Adaptor protein Lnk associates with Tyr568 in c-Kit
Authors: Gueller Saskia , Gery Sigal , Nowak Verena , Liu Liqin , Serve Hubert , Koeffler H. Phillip
Published: July 2008

The adaptor protein Lnk is expressed in haemopoietic cells and plays a critical role in haemopoiesis. Animal model studies demonstrated that Lnk acts as a broad inhibitor of signalling pathways in haemopoietic lineages. Lnk belongs to a family of proteins sharing several structural motifs, including an SH2 (Src homology 2) domain which binds phosphotyrosine residues in various signal-transducing proteins. The SH2 domain is essential for Lnk-mediated negative regulation of several cytokine receptors [e.g. Mpl, EpoR (erythropoietin receptor), c-Kit]. Therefore inhibition of the binding of Lnk to cytokine receptors might lead to enhanced downstream signalling of the receptor and thereby to improved haemopoiesis in response to exposure to cytokines (e.g. erythropoietin in anaemic patients). This hypothesis led us to define the exact binding site of Lnk to the stem cell factor receptor c-Kit. Pull-down experiments using GST (glutathione transferase)-fusion proteins of the different domains of c-Kit showed that Lnk almost exclusively binds to the phosphorylated juxtamembrane domain. Binding of Lnk to the juxtamembrane domain was abolished by point mutation of Tyr568 and was competed by peptides with a phosphotyrosine residue at position 568. Co-immunoprecipitation with full-length wild-type or Y568F mutant c-Kit and Lnk confirmed these results, thus showing the importance of this phosphorylated tyrosine residue. Lnk bound directly to c-Kit without requiring other interacting partners. The identification of the binding site of Lnk to c-Kit will be useful to discover inhibitory molecules that prevent the binding of these two proteins, thus making haemopoietic cells more sensitive to growth factors.
The selectivity of inhibitors of protein kinase CK2: an update
Authors: Pagano Mario A. , Bain Jenny , Kazimierczuk Zygmunt , Sarno Stefania , Ruzzene Maria , Di Maira Giovanni , Elliott Matthew , Orzeszko Andrzej , Cozza Giorgio , Meggio Flavio , Pinna Lorenzo A.
Published: July 2008

CK2 (casein kinase 2) is a very pleiotropic serine/threonine protein kinase whose abnormally high constitutive activity has often been correlated to pathological conditions with special reference to neoplasia. The two most widely used cell permeable CK2 inhibitors, TBB (4,5,6,7-tetrabromo-1H-benzotriazole) and DMAT (2-dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole), are marketed as quite specific CK2 blockers. In the present study we show, by using a panel of approx. 80 protein kinases, that DMAT and its parent compound TBI (or TBBz; 4,5,6,7-tetrabromo-1H-benzimidazole) are potent inhibitors of several other kinases, with special reference to PIM (provirus integration site for Moloney murine leukaemia virus)1, PIM2, PIM3, PKD1 (protein kinase D1), HIPK2 (homeodomain-interacting protein kinase 2) and DYRK1a (dual-specificity tyrosine-phosphorylated and -regulated kinase 1a). In contrast, TBB is significantly more selective toward CK2, although it also inhibits PIM1 and PIM3. In an attempt to improve selectivity towards CK2 a library of 68 TBB/TBI-related compounds have been tested for their ability to discriminate between CK2, PIM1, HIPK2 and DYRK1a, ending up with seven compounds whose efficacy toward CK2 is markedly higher than that toward the second most inhibited kinase. Two of these, K64 (3,4,5,6,7-pentabromo-1H-indazole) and K66 (1-carboxymethyl-2-dimethylamino-4,5,6,7-tetrabromo-benzimidazole), display an overall selectivity much higher than TBB and DMAT when tested on a panel of 80 kinases and display similar efficacy as inducers of apoptosis.
English Speech Sound Development in Preschool-Aged Children From Bilingual English–Spanish Environments
Authors: Gildersleeve-Neumann Christina E. , Kester Ellen S. , Davis Barbara L. , Peña Elizabeth D.
Published: July 2008

Purpose

English speech acquisition by typically developing 3- to 4-year-old children with monolingual English was compared to English speech acquisition by typically developing 3- to 4-year-old children with bilingual English–Spanish backgrounds. We predicted that exposure to Spanish would not affect the English phonetic inventory but would increase error frequency and type in bilingual children.

Method

Single-word speech samples were collected from 33 children. Phonetically transcribed samples for the 3 groups (monolingual English children, English–Spanish bilingual children who were predominantly exposed to English, and English–Spanish bilingual children with relatively equal exposure to English and Spanish) were compared at 2 time points and for change over time for phonetic inventory, phoneme accuracy, and error pattern frequencies.

Results

Children demonstrated similar phonetic inventories. Some bilingual children produced Spanish phonemes in their English and produced few consonant cluster sequences. Bilingual children with relatively equal exposure to English and Spanish averaged more errors than did bilingual children who were predominantly exposed to English. Both bilingual groups showed higher error rates than English-only children overall, particularly for syllable-level error patterns. All language groups decreased in some error patterns, although the ones that decreased were not always the same across language groups. Some group differences of error patterns and accuracy were significant. Vowel error rates did not differ by language group.

Conclusion

Exposure to English and Spanish may result in a higher English error rate in typically developing bilinguals, including the application of Spanish phonological properties to English. Slightly higher error rates are likely typical for bilingual preschool-aged children. Change over time at these time points for all 3 groups was similar, suggesting that all will reach an adult-like system in English with exposure and practice.
Preschool Teachers' Fidelity in Implementing a Comprehensive Language-Rich Curriculum
Authors: Pence Khara L. , Justice Laura M. , Wiggins Alice K.
Published: July 2008

Purpose

This study examined preschool teachers' fidelity to the language-focused curriculum (LFC; B. Bunce, 1995), a comprehensive classroom curriculum designed to improve at-risk children’s language outcomes through targeted improvements to a classroom’s activity contexts (e.g., dramatic play, art, storybook reading) and instructional processes (e.g., teacher use of open-ended questions, recasts, and expansions). Specific aims included to (a) examine program differentiation by determining how measures of activity contexts and instructional processes differentiated treatment and comparison teachers, (b) determine treatment teachers' adherence to both activity contexts and instructional processes over an entire academic year, and (c) determine treatment teachers' reported quality of program delivery and comfort with curriculum implementation.

Method

Fourteen preschool teachers were randomly assigned to implement the LFC or to maintain their prevailing curriculum. Fidelity was measured 3 times over an academic year using a curriculum fidelity checklist.

Results

LFC teachers exhibited fidelity to activity contexts more readily than to instructional processes. Teacher use of language-focused instructional processes was relatively low even after a year of LFC implementation.

Conclusion

This study supports the need for speech-language pathologists to work closely with preschool educators to implement the activity contexts and instructional processes associated with high-quality preschool language-learning environments.
Knowledge of Morphologically Complex Words: A Developmental Study of Older Children and Young Adolescents
Authors: Nippold Marilyn A. , Sun Lei
Published: July 2008

Purpose

This study examined knowledge of derived nominals (e.g., measurement, prediction) and derived adjectives (e.g., algebraic, molecular) in older children and young adolescents. Little was known about students' comprehension of these morphologically complex words that occur in textbooks that are used in public schools to teach challenging subjects such as science, mathematics, social studies, health, and literature.

Method

The Word Knowledge Task (WKT), designed for the present study, was used to examine participants' comprehension of 15 derived nominals and 15 derived adjectives that were selected from state-adopted textbooks. This written, multiple-choice task was administered to 10-year-old children and 13-year-old adolescents (N= 94) who were attending public schools. All participants spoke English and were typical achievers.

Results

The findings indicated that the adolescents outperformed the children on both types of derived words; the derived nominals were more difficult than the derived adjectives for both groups; and comprehension was associated with frequency of occurrence in print, with easier words generally more common than more difficult ones.

Implications

Knowledge of morphologically complex words such as derived nominals and derived adjectives is a late linguistic attainment. Given the importance of these words for academic success, instructional programs are needed to ensure that children and adolescents are able to learn their meanings using appropriate strategies.
Nonspeech Oral Motor Treatment Issues Related to Children With Developmental Speech Sound Disorders
Authors: Ruscello Dennis M.
Published: July 2008

Purpose

This article examines nonspeech oral motor treatments (NSOMTs) in the population of clients with developmental speech sound disorders. NSOMTs are a collection of nonspeech methods and procedures that claim to influence tongue, lip, and jaw resting postures; increase strength; improve muscle tone; facilitate range of motion; and develop muscle control. In the case of developmental speech sound disorders, NSOMTs are employed before or simultaneous with actual speech production treatment.

Method

First, NSOMTs are defined for the reader, and there is a discussion of NSOMTs under the categories of active muscle exercise, passive muscle exercise, and sensory stimulation. Second, different theories underlying NSOMTs along with the implications of the theories are discussed. Finally, a review of pertinent investigations is presented.

Results

The application of NSOMTs is questionable due to a number of reservations that include (a) the implied cause of developmental speech sound disorders, (b) neurophysiologic differences between the limbs and oral musculature, (c) the development of new theories of movement and movement control, and (d) the paucity of research literature concerning NSOMTs.

Clinical Implication

There is no substantive evidence to support NSOMTs as interventions for children with developmental speech sound disorders.
Band offset of InGaAs(N)∕GaAs interfaces from first principles
Authors: Komsa Hannu-Pekka , Arola Eero , Rantala Tapio T.
Published: June 2008

Valence-band offsets of the InGaAs∕GaAs(001) and InGaAsN∕GaAs(001) interfaces are calculated from first principles. For InGaAs, we study the concentrations up to 25% of indium and for InGaAsN up to 12.5% of indium with 3% of nitrogen. Even though the band offset of the InGaAs∕GaAs interface has a nearly linear dependence on the indium concentration, band offset of the InGaAsN∕GaAs interface is strongly influenced by the amount of In–N bonds. Even a type-II band offset is found in the case of all indium located near to nitrogen and low strain of the InGaAsN layer.
Design of arbitrarily shaped concentrators based on conformally optical transformation of nonuniform rational B-spline surfaces
Authors: Jiang Wei Xiang , Cui Tie Jun , Cheng Qiang , Chin Jessie Yao , Yang Xin Mi , Liu Ruopeng , Smith David R.
Published: June 2008

We study the design of arbitrarily shaped electromagnetic (EM) concentrators and their potential applications. To obtain closed-form formulas of EM parameters for an arbitrarily shaped concentrator, we employ nonuniform rational B-spline (NURBS) to represent the geometrical boundary. Using the conformally optical transformation of NURBS surfaces, we propose the analytical design of arbitrarily shaped concentrators, which are composed of anisotropic and inhomogeneous metamaterials with closed-form constitutive tensors. The designed concentrators are numerically validated by full-wave simulations, which show perfectly directed EM behaviors. As one of the potential applications, we demonstrate a way to amplify plane waves using a rectangular concentrator, which is much more efficient and easier than the existing techniques. Using NURBS expands the generality of the transformation optics and could lead toward making a very general tool that would interface with commercial softwares such as 3D STUDIOMAX and MAYA.
GaN for x-ray detection
Authors: Duboz Jean-Yves , Laügt Marguerite , Schenk David , Beaumont Bernard , Reverchon Jean-Luc , Wieck Andreas D. , Zimmerling Tino
Published: June 2008

The potential of GaN based materials for x-ray detection is investigated. The absorption coefficient in GaN is measured as a function of photon energy between 6 and 40keV. Metal-semiconductor-metal photodetectors are fabricated and characterized. The response dependence on bias, the temporal dynamics, and the response dependence on detector geometry all together point toward a mixing of photovoltaic and photoconductive effects. Thanks to a large photoconductive gain, the detector has a decent responsivity at the expense of a large response time.
Integration of site-controlled pyramidal quantum dots and photonic crystal membrane cavities
Authors: Gallo P. , Felici M. , Dwir B. , Atlasov K. A. , Karlsson K. F. , Rudra A. , Mohan A. , Biasiol G. , Sorba L. , Kapon E.
Published: June 2008

The authors demonstrate the deterministic coupling between a single, site-controlled InGaAs∕GaAs pyramidal quantum dot (QD) and a photonic crystal membrane cavity defect. The growth of self-ordered pyramidal QDs in small (300nm base side) tetrahedral recesses etched on (111)B GaAs substrates was developed in order to allow their integration within the thin GaAs membranes. Accurate (better than 50nm) positioning of the QD with respect to the optical cavity mode is achieved reproducibly owing to the site control. Coupling of the dot emission with the cavity mode is evidenced in photoluminescence measurements. The deterministic positioning of the pyramidal QDs and the control of their emission spectrum opens the way for devices based on QDs integrated with coupled nanocavities.
Capacitance transient and current-/capacitance-voltage study of direct silicon bonded (110)∕(100) interface
Authors: Yu Xuegong , Lu Jinggang , Rozgonyi George
Published: June 2008

This letter has developed a procedure for quantitatively evaluating the electrical levels at a (110)∕(100) interfacial grain boundary (GB) in p-type direct silicon bonded wafers by combining current-/capacitance-voltage (I-V,C-V) and capacitance transient techniques. It is found that GB states can be positively charged and induce a high potential barrier. The local distribution of charge density deduced from I-V∕C-V measurements shows that the state density is constant, ∼2×1012cm−2, in the energy range Ev+0.36–0.50eV. Meanwhile, capacitance transient technique reveals the states in the energy range Ev+0.33–0.43eV with capture cross sections of 10−17cm2, and the state density is consistent with the results by I-V∕C-V deconvolution.
Identification of dispersion-dependent hexagonal cavity modes of an individual ZnO nanonail
Authors: Liu Jinzhang , Lee Soonil , Ahn Y. H. , Park Ji-Yong , Koh Ken Ha , Park Kyung Ho
Published: June 2008

The hexagonal resonator characteristics of an individual ZnO-nanonail’s head were investigated via spatially resolved cathodoluminescence (CL) at room temperature. The positions of most of distinct CL peaks in visible range were well matched to those of whispering gallery modes (WGMs) of a hexagonal dielectric cavity when we took birefringence and dispersion of refractive indices into account. The broad and weak peaks for TE polarization in long wavelength range were consistent with refractive-index values below the threshold for total internal inflection. CL peaks that were not matched to WGMs were identified as either triangular quasi-WGM or Fabry–Pérot resonance modes.
Giant microwave tunability in FeGaB/lead magnesium niobate-lead titanate multiferroic composites
Authors: Lou J. , Reed D. , Pettiford C. , Liu M. , Han P. , Dong S. , Sun N. X.
Published: June 2008

Giant magnetoelectric coupling at both microwave frequencies and dc was observed in an FeGaB/lead magnesium niobate-lead titanate microwave multiferroic composite. A record high microwave frequency tunability of Δf=900MHz or Δf∕f=58% was demonstrated with the change of an external electric field from −6to+2kV∕cm. A strong electric field dependence of magnetic hysteresis loops was also observed. Such multiferroic composite provides great opportunities for electrostatically tunable microwave devices.
Comparison of leakage behaviors in p- and n-type metal-oxide-semiconductor capacitors with hafnium silicon oxynitride gate dielectric by electron-beam-induced current
Authors: Chen Jun , Sekiguchi Takashi , Fukata Naoki , Takase Masami , Chikyo Toyohiro , Yamabe Kikuo , Hasunuma Ryu , Sato Motoyuki , Nara Yasuo , Yamada Keisaku
Published: June 2008

The gate leakage behaviors of p- and n-type metal-oxide-semiconductor (p−∕nMOS) capacitors with hafnium silicon oxynitride (HfSiON) gate dielectric were microscopically investigated by electron-beam-induced current (EBIC) technique. Carrier separated EBIC measurement has found that in nonstressed samples, hole conduction in pMOS is significantly enhanced by trap-assisted tunneling, while electron conduction in nMOS is independent of traps. After voltage stress, traps are induced in nMOS and enhanced electron conduction.
Tunable generation of Bessel beams with a fluidic axicon
Authors: Milne Graham , Jeffries Gavin D. M. , Chiu Daniel T.
Published: June 2008

This paper describes a tunable fluidic conical lens, or axicon, for the generation and dynamic reconfiguration of Bessel beams. When illuminated with a Gaussian laser beam, our fluidic axicon generates a diverging beam with an annular cross section. By varying the refractive index of the solution that fills our device, we can vary easily the spatial properties of the resulting Bessel beam.
Dependence of antibody-mediated presentation of antigen on FcRn
Authors: Qiao Shuo-Wang , Kobayashi Kanna , Johansen Finn-Eirik , Sollid Ludvig M. , Andersen Jan Terje , Milford Edgar , Roopenian Derry C. , Lencer Wayne I. , Blumberg Richard S.
Published: July 2008

The neonatal Fc receptor for IgG (FcRn) is a distant member of the MHC class I protein family. It binds IgG and albumin in a pH-dependent manner and protects these from catabolism by diverting them from a degradative fate in lysosomes. In addition, FcRn-mediated IgG transport across epithelial barriers is responsible for the transmission of IgG from mother to infant and can also enhance IgG-mediated antigen uptake across mucosal epithelia. We now show a previously undescribed role for FcRn in mediating the presentation of antigens by dendritic cells when antigens are present as a complex with antibody by uniquely directing multimeric immune complexes, but not monomeric IgG, to lysosomes.
Agonist-selective signaling is determined by the receptor location within the membrane domains
Authors: Zheng Hui , Chu Ji , Qiu Yu , Loh Horace H. , Law Ping-Yee
Published: July 2008

The basis for agonist-selective signaling was investigated by using the μ-opioid receptor (MOR) as a model. In the absence of agonist, MOR located within the lipid raft domains, whereas etorphine, but not morphine, induced the translocation of MOR from lipid raft to nonraft domains, similar to the action of methyl-β-cyclodextrin. The etorphine-induced MOR translocation required the dissociation of the receptor from Gαi2 first and then the binding of β-arrestin. In contrast, the low affinity of the morphine–MOR complex for β-arrestin and the rebinding of Gαi2 after GTP hydrolysis retained the complex within the lipid raft domains. Disruption of the MOR–Gαi2 interaction, either by deleting the
276
RRITR
280
sequence of MOR or knocking down the level of Gαi2, resulted in the translocation of MOR to the nonraft domains. In addition, lipid raft location of MOR was critical for G protein-dependent signaling, such as etorphine- and morphine-mediated inhibition of adenylyl cyclase activity and morphine-induced ERK phosphorylation, whereas β-arrestin-dependent, etorphine-induced ERK phosphorylation required MOR to translocate into the nonraft domains. Thus, agonist-selective signaling is regulated by the location of MOR, which is determined by interactions of MOR with G proteins and β-arrestin.
Transcription factor MEF2C influences neural stem/progenitor cell differentiation and maturation
in vivo
Authors: Li Hao , Radford Jonathan C. , Ragusa Michael J. , Shea Katherine L. , McKercher Scott R. , Zaremba Jeffrey D. , Soussou Walid , Nie Zhiguo , Kang Yeon-Joo , Nakanishi Nobuki , Okamoto Shu-ichi , Roberts Amanda J. , Schwarz John J. , Lipton Stuart A.
Published: July 2008

Emerging evidence suggests that myocyte enhancer factor 2 (MEF2) transcription factors act as effectors of neurogenesis in the brain, with MEF2C the predominant isoform in developing cerebrocortex. Here, we show that conditional knockout of
Mef2c
in nestin-expressing neural stem/progenitor cells (NSCs) impaired neuronal differentiation
in vivo
, resulting in aberrant compaction and smaller somal size. NSC proliferation and survival were not affected. Conditional null mice surviving to adulthood manifested more immature electrophysiological network properties and severe behavioral deficits reminiscent of Rett syndrome, an autism-related disorder. Our data support a crucial role for MEF2C in programming early neuronal differentiation and proper distribution within the layers of the neocortex.
Gene
1.7
of bacteriophage T7 confers sensitivity of phage growth to dideoxythymidine
Authors: Tran Ngoc Q. , Rezende Lisa F. , Qimron Udi , Richardson Charles C. , Tabor Stanley
Published: July 2008

Bacteriophage T7 DNA polymerase efficiently incorporates dideoxynucleotides into DNA, resulting in chain termination. Dideoxythymidine (ddT) present in the medium at levels not toxic to
Escherichia coli
inhibits phage T7. We isolated 95 T7 phage mutants that were resistant to ddT. All contained a mutation in T7 gene
1.7
, a nonessential gene of unknown function. When gene
1.7
was expressed from a plasmid, T7 phage resistant to ddT still arose; analysis of 36 of these mutants revealed that all had a single mutation in gene
5
, which encodes T7 DNA polymerase. This mutation changes tyrosine-526 to phenylalanine, which is known to increase dramatically the ability of T7 DNA polymerase to discriminate against dideoxynucleotides. DNA synthesis in cells infected with wild-type T7 phage was inhibited by ddT, suggesting that it resulted in chain termination of DNA synthesis in the presence of gene 1.7 protein. Overexpression of gene
1.7
from a plasmid rendered
E. coli
cells sensitive to ddT, indicating that no other T7 proteins are required to confer sensitivity to ddT.
Lahemaa: The Paradox of the USSR's First National Park*
Authors: Smurr Robert W.
Published: June 2008

[A] place belongs forever to whoever claims it the hardest, remembers it most obsessively, wrenches it from itself, shapes it, renders it, loves it so radically that he remakes it in his own image.

Joan Didion, TheWhite Album

The residents of Lahemaa have evolved into Lahemaa folk, who look upon the park with the eyes of a caretaker, who preserve and protect it … [they] have developed a keen interest in looking after their home and environment.

Ilmar Epner, “15 aastat Lahemaa Rahvusparkii”
Elections, Legitimacy, Media and Democracy: The Case of Georgia
Authors: Davis Sue
Published: June 2008

Elections are one of the major ways in which democratic governments maintain legitimacy. Do elections serve the same functions in transitioning, non-democratic, or semi-democratic systems? Perhaps the relationship between elections and legitimacy is different in systems that are not fully democratic? And what of the media? Is their role the same or is the role they play dependent upon the type of system in which they exist? The Republic of Georgia offers an interesting case in which to look at these relationships. I would posit that in transitioning, non-democratic, and semi-democratic systems, elections serve a different function than in a fully democratic society and the media are one tool that leaders in such systems can use to enhance their legitimacy. When non-democratic leaders enjoy popularity, there is no need to finesse the media since positive coverage is easy to come by when you are popular. But if your popularity is waning and democratic habits are not well ingrained, the temptation to overtly or covertly subvert the media can be quite intense. So instead of maintaining legitimacy, elections may serve to create legitimacy or at least the appearance of legitimacy when legitimacy is lacking. To that end, regimes and leaders cannot afford to lose, and moreover need to win, elections by large margins if their legitimacy is questionable. Therefore, control over the media is more important when this is the case. In fact, there may be an inverse relationship between media freedom and regime insecurity, as the insecurity of the regime goes up, the freedom of the media goes down. Couple this tendency with the fact that the media in these transitioning systems have not fully become a “fourth estate” that is strong, independent, and can hold the government and political leaders accountable and you have a climate in which the media are harassed, biased, and often co-opted. Georgia, through the 2000 presidential election, is such a political system.
The Roma in Post-Communist Eastern Europe: Questions of Ethnic Conflict and Ethnic Peace
Authors: Crowe David M.
Published: June 2008

The collapse of communism in Central and Eastern Europe promised bold opportunities for the various ethnic groups populating that vast, diverse region. Yet if history had any lessons to teach these groups it was that democracy, or at least the political systems that emerged in the midst of the rubble of the Berlin Wall between 1989 and 1991, was no guarantor of whatever idealized rights the region's ethnic groups hoped would come in the wake of the collapse of the communist dictatorships that had dominated these parts of Europe for decades. Communism, had, in many instances, done nothing more than stifle the festering ethnic tensions that had exploded in the nineteenth century and short-circuited the complex, lengthy process of resolving these conflicts. Consequently, for those knowledgeable about the essence of these conflicts, it should have come as no surprise that Yugoslavia, for example, was torn asunder by ethnic violence so terrifying that it took the intervention of the Western world's great powers to end the most violent aspects of these wars of ethnicity.
Cleavage of the signaling mucin Msb2 by the aspartyl protease Yps1 is required for MAPK activation in yeast
Authors: Vadaie Nadia , Dionne Heather , Akajagbor Darowan S. , Nickerson Seth R. , Krysan Damian J. , Cullen Paul J.
Published: June 2008

Signaling mucins are cell adhesion molecules that activate RAS/RHO guanosine triphosphatases and their effector mitogen-activated protein kinase (MAPK) pathways. We found that the Saccharomyces cerevisiae mucin Msb2p, which functions at the head of the Cdc42p-dependent MAPK pathway that controls filamentous growth, is processed into secreted and cell-associated forms. Cleavage of the extracellular inhibitory domain of Msb2p by the aspartyl protease Yps1p generated the active form of the protein by a mechanism incorporating cellular nutritional status. Activated Msb2p functioned through the tetraspan protein Sho1p to induce MAPK activation as well as cell polarization, which involved the Cdc42p guanine nucleotide exchange factor Cdc24p. We postulate that cleavage-dependent activation is a general feature of signaling mucins, which brings to light a novel regulatory aspect of this class of signaling adhesion molecule.
SERCA pump activity is physiologically regulated by presenilin and regulates amyloid β production
Authors: Green Kim N. , Demuro Angelo , Akbari Yama , Hitt Brian D. , Smith Ian F. , Parker Ian , LaFerla Frank M.
Published: June 2008

In addition to disrupting the regulated intramembraneous proteolysis of key substrates, mutations in the presenilins also alter calcium homeostasis, but the mechanism linking presenilins and calcium regulation is unresolved. At rest, cytosolic Ca2+ is maintained at low levels by pumping Ca2+ into stores in the endoplasmic reticulum (ER) via the sarco ER Ca2+-ATPase (SERCA) pumps. We show that SERCA activity is diminished in fibroblasts lacking both PS1 and PS2 genes, despite elevated SERCA2b steady-state levels, and we show that presenilins and SERCA physically interact. Enhancing presenilin levels in Xenopus laevis oocytes accelerates clearance of cytosolic Ca2+, whereas higher levels of SERCA2b phenocopy PS1 overexpression, accelerating Ca2+ clearance and exaggerating inositol 1,4,5-trisphosphate–mediated Ca2+ liberation. The critical role that SERCA2b plays in the pathogenesis of Alzheimer's disease is underscored by our findings that modulating SERCA activity alters amyloid β production. Our results point to a physiological role for the presenilins in Ca2+ signaling via regulation of the SERCA pump.
Involvement of autophagy in trypsinogen activation within the pancreatic acinar cells
Authors: Hashimoto Daisuke , Ohmuraya Masaki , Hirota Masahiko , Yamamoto Akitsugu , Suyama Koichi , Ida Satoshi , Okumura Yuushi , Takahashi Etsuhisa , Kido Hiroshi , Araki Kimi , Baba Hideo , Mizushima Noboru , Yamamura Ken-ichi
Published: June 2008

Autophagy is mostly a nonselective bulk degradation system within cells. Recent reports indicate that autophagy can act both as a protector and killer of the cell depending on the stage of the disease or the surrounding cellular environment (for review see Cuervo, A.M. 2004. Trends Cell Biol. 14:70–77). We found that cytoplasmic vacuoles induced in pancreatic acinar cells by experimental pancreatitis were autophagic in origin, as demonstrated by microtubule-associated protein 1 light chain 3 expression and electron microscopy experiments. To analyze the role of macroautophagy in acute pancreatitis, we produced conditional knockout mice lacking the autophagy-related 5 gene in acinar cells. Acute pancreatitis was not observed, except for very mild edema in a restricted area, in conditional knockout mice. Unexpectedly, trypsinogen activation was greatly reduced in the absence of autophagy. These results suggest that autophagy exerts devastating effects in pancreatic acinar cells by activation of trypsinogen to trypsin in the early stage of acute pancreatitis through delivering trypsinogen to the lysosome.
Rho-GTPase–dependent filamentous actin dynamics coordinate vesicle targeting and exocytosis during tip growth
Authors: Lee Yong Jik , Szumlanski Amy , Nielsen Erik , Yang Zhenbiao
Published: June 2008

The dynamic activity of tip-localized filamentous actin (F-actin) in pollen tubes is controlled by counteracting RIC4 and RIC3 pathways downstream of the ROP1 guanosine triphosphatase promoting actin assembly and disassembly, respectively. We show here that ROP1 activation is required for both the polar accumulation and the exocytosis of vesicles at the plasma membrane apex. The apical accumulation of exocytic vesicles oscillated in phase with, but slightly behind, apical actin assembly and was enhanced by overexpression of RIC4. However, RIC4 overexpression inhibited exocytosis, and this inhibition could be suppressed by latrunculin B treatment or RIC3 overexpression. We conclude that RIC4-dependent actin assembly is required for polar vesicle accumulation, whereas RIC3-mediated actin disassembly is required for exocytosis. Thus ROP1-dependent F-actin dynamics control tip growth through spatiotemporal coordination of vesicle targeting and exocytosis.
Loss of miRNA biogenesis induces p19Arf-p53 signaling and senescence in primary cells
Authors: Mudhasani Rajini , Zhu Zhiqing , Hutvagner Gyorgy , Eischen Christine M. , Lyle Stephen , Hall Lisa L. , Lawrence Jeanne B. , Imbalzano Anthony N. , Jones Stephen N.
Published: June 2008

Dicer, an enzyme involved in microRNA (miRNA) maturation, is required for proper cell differentiation and embryogenesis in mammals. Recent evidence indicates that Dicer and miRNA may also regulate tumorigenesis. To better characterize the role of miRNA in primary cell growth, we generated Dicer-conditional mice. Ablation of Dicer and loss of mature miRNAs in embryonic fibroblasts up-regulated p19Arf and p53 levels, inhibited cell proliferation, and induced a premature senescence phenotype that was also observed in vivo after Dicer ablation in the developing limb and in adult skin. Furthermore, deletion of the Ink4a/Arf or p53 locus could rescue fibroblasts from premature senescence induced by Dicer ablation. Although levels of Ras and Myc oncoproteins appeared unaltered, loss of Dicer resulted in increased DNA damage and p53 activity in these cells. These results reveal that loss of miRNA biogenesis activates a DNA damage checkpoint, up-regulates p19Arf-p53 signaling, and induces senescence in primary cells.
A Close Association of RyRs with Highly Dense Clusters of Ca2+-activated Cl− Channels Underlies the Activation of STICs by Ca2+ Sparks in Mouse Airway Smooth Muscle
Authors: Bao Rongfeng , Lifshitz Lawrence M. , Tuft Richard A. , Bellvé Karl , Fogarty Kevin E. , ZhuGe Ronghua
Published: June 2008

Ca2+ sparks are highly localized, transient releases of Ca2+ from sarcoplasmic reticulum through ryanodine receptors (RyRs). In smooth muscle, Ca2+ sparks trigger spontaneous transient outward currents (STOCs) by opening nearby clusters of large-conductance Ca2+-activated K+ channels, and also gate Ca2+-activated Cl− (Cl(Ca)) channels to induce spontaneous transient inward currents (STICs). While the molecular mechanisms underlying the activation of STOCs by Ca2+ sparks is well understood, little information is available on how Ca2+ sparks activate STICs. In the present study, we investigated the spatial organization of RyRs and Cl(Ca) channels in spark sites in airway myocytes from mouse. Ca2+ sparks and STICs were simultaneously recorded, respectively, with high-speed, widefield digital microscopy and whole-cell patch-clamp. An image-based approach was applied to measure the Ca2+ current underlying a Ca2+ spark (ICa(spark)), with an appropriate correction for endogenous fixed Ca2+ buffer, which was characterized by flash photolysis of NPEGTA. We found that ICa(spark) rises to a peak in 9 ms and decays with a single exponential with a time constant of 12 ms, suggesting that Ca2+ sparks result from the nonsimultaneous opening and closure of multiple RyRs. The onset of the STIC lags the onset of the ICa(spark) by less than 3 ms, and its rising phase matches the duration of the ICa(spark). We further determined that Cl(Ca) channels on average are exposed to a [Ca2+] of 2.4 μM or greater during Ca2+ sparks. The area of the plasma membrane reaching this level is <600 nm in radius, as revealed by the spatiotemporal profile of [Ca2+] produced by a reaction-diffusion simulation with measured ICa(spark). Finally we estimated that the number of Cl(Ca) channels localized in Ca2+ spark sites could account for all the Cl(Ca) channels in the entire cell. Taken together these results lead us to propose a model in which RyRs and Cl(Ca) channels in Ca2+ spark sites localize near to each other, and, moreover, Cl(Ca) channels concentrate in an area with a radius of ∼600 nm, where their density reaches as high as 300 channels/μm2. This model reveals that Cl(Ca) channels are tightly controlled by Ca2+ sparks via local Ca2+ signaling.
Intracellular Proton Regulation of ClC-0
Authors: Zifarelli Giovanni , Murgia Anna Rosa , Soliani Paolo , Pusch Michael
Published: June 2008

Some CLC proteins function as passive Cl− ion channels whereas others are secondary active chloride/proton antiporters. Voltage-dependent gating of the model Torpedo channel ClC-0 is modulated by intracellular and extracellular pH, possibly reflecting a mechanistic relationship with the chloride/proton coupling of CLC antiporters. We used inside-out patch clamp measurements and mutagenesis to explore the dependence of the fast gating mechanism of ClC-0 on intracellular pH and to identify the putative intracellular proton acceptor(s). Among the tested residues (S123, K129, R133, K149, E166, F214L, S224, E226, V227, C229, R305, R312, C415, H472, F418, V419, P420, and Y512) only mutants of E166, F214, and F418 qualitatively changed the pHint dependence. No tested amino acid emerged as a valid candidate for being a pH sensor. A detailed kinetic analysis of the dependence of fast gate relaxations on pHint and [Cl−]int provided quantitative constraints on possible mechanistic models of gating. In one particular model, a proton is generated by the dissociation of a water molecule in an intrapore chloride ion binding site. The proton is delivered to the side chain of E166 leading to the opening of the channel, while the hydroxyl ion is stabilized in the internal/central anion binding site. Deuterium isotope effects confirm that proton transfer is rate limiting for fast gate opening and that channel closure depends mostly on the concentration of OH− ions. The gating model is in natural agreement with the finding that only the closing rate constant, but not the opening rate constant, depends on pHint and [Cl−]int.
Screening for Carriage of Methicillin-Resistant Staphylococcus aureus Shortly After Exposure May Lead to False-Negative Results
Authors: Evison John , Mühlemann Kathrin
Published: June 2008

We evaluated a double screening strategy for carriage of methicillin-resistant Staphylococcus aureus (MRSA) in patients exposed to a newly detected MRSA carrier. If the first screening of the exposed patient yielded negative results, screening was repeated 4 days later. This strategy detected 12 (28%) of the 43 new MRSA carriers identified during the study period. The results suggest that there is an incubation period before MRSA carriage is detectable.
The optimized interpolation of fish positions and speeds in an array of fixed acoustic receivers
Authors: Hedger Richard D. , Martin François , Dodson Julian J. , Hatin Daniel , Caron François , Whoriskey Fred G.
Published: June 2008

Hedger, R. D., Martin, F., Dodson, J, J., Hatin, D., Caron, F., and Whoriskey, F. G. 2008. The optimized interpolation of fish positions and speeds in an array of fixed acoustic receivers. – ICES Journal of Marine Science, 65: 1248–1259. The principal method for interpolating the positions and speeds of tagged fish within an array of fixed acoustic receivers is the weighted-mean method, which uses a box-kernel estimator, one of the simplest smoothing options available. This study aimed to determine the relative error of alternative, non-parametric regression methods for estimating these parameters. It was achieved by predicting the positions and speeds of three paths made through a dense array of fixed acoustic receivers within a coastal embayment (Gaspé Bay, Québec, Canada) by a boat with a GPS trailing an ultrasonic transmitter. Transmitter positions and speeds were estimated from the receiver data using kernel estimators, with box and normal kernels and the kernel size determined arbitrarily, and by several non-parametric methods, i.e. a kernel estimator, a smoothing spline, and local polynomial regression, with the kernel size or smoothing span determined by cross-validation. Prediction error of the kernel estimator was highly dependent upon kernel size, and a normal kernel produced less error than the box kernel. Of the methods using cross-validation, local polynomial regression produced least error, suggesting it as the optimal method for interpolation. Prediction error was also strongly dependent on array density. The local polynomial regression method was used to determine the movement patterns of a sample of tagged Atlantic salmon (Salmo salar) smolt and kelt, and American eel (Anguilla rostrata). Analysis of the estimates from local polynomial regression suggested that this was a suitable method for monitoring patterns of fish movement.
A cellular isolation system for real-time single-cell oxygen consumption monitoring
Authors: Dragavon Joe , Molter Tim , Young Cody , Strovas Tim , McQuaide Sarah , Holl Mark , Zhang Meng , Cookson Brad , Jen Alex , Lidstrom Mary , Meldrum Deirdre , Burgess Lloyd
Published: July 2008

The development of a cellular isolation system (CIS) that enables the monitoring of single-cell oxygen consumption rates in real time is presented. The CIS was developed through a multidisciplinary effort within the Microscale Life Sciences Center (MLSC) at the University of Washington. The system comprises arrays of microwells containing Pt-porphyrin-embedded polystyrene microspheres as the reporter chemistry, a lid actuator system and a gated intensified imaging camera, all mounted on a temperature-stabilized confocal microscope platform. Oxygen consumption determination experiments were performed on RAW264.7 mouse macrophage cells as proof of principle. Repeatable and consistent measurements indicate that the oxygen measurements did not adversely affect the physiological state of the cells measured. The observation of physiological rates in real time allows studies of cell-to-cell heterogeneity in oxygen consumption rate to be performed. Such studies have implications in understanding the role of mitochondrial function in the progression of inflammatory-based diseases, and in diagnosing and treating such diseases.
Lab-on-a-chip technologies for proteomic analysis from isolated cells
Authors: Sedgwick H , Caron F , Monaghan P.B , Kolch W , Cooper J.M
Published: July 2008

Lab-on-a-chip systems offer a versatile environment in which low numbers of cells and molecules can be manipulated, captured, detected and analysed. We describe here a microfluidic device that allows the isolation, electroporation and lysis of single cells. A431 human epithelial carcinoma cells, expressing a green fluorescent protein-labelled actin, were trapped by dielectrophoresis within an integrated lab-on-a-chip device containing saw-tooth microelectrodes. Using these same trapping electrodes, on-chip electroporation was performed, resulting in cell lysis. Protein release was monitored by confocal fluorescence microscopy.