bluuebunny/crossref_metadata_2025 huggingface dataset:
Laser threshold reduction in an all-spiro guest–host system
Authors: Schneider D. , Rabe T. , Riedl T. , Dobbertin T. , Kröger M. , Becker E. , Johannes H.-H. , Kowalsky W. , Weimann T. , Wang J. , Hinze P.
Published: September 2004

We report on stimulated emission in an all-spiro guest–host (G–H) system. Different doping concentrations of the guest molecule 2,2′,7,7′-tetrakis(2,2-diphenylvinyl)spiro-9,9′-bifluorene in the host material 2,7-bis(biphenyl-4-yl)-2′, 7′-di-tert-butyl-9,9′-spirobifluorene were investigated for amplified spontaneous emission (ASE) and distributed feedback (DFB) lasing. The ASE maximum could be shifted over 20nm by variation of the doping concentration. DFB lasing is observed in the pure host, the pure guest material, and in the G–H system. The laser wavelength can be tuned from 401.5 to 529.3nm by changing the grating period of the Bragg reflector and the doping concentration. A minimum threshold energy density of 6μJ∕cm2 was observed in second-order DFB structures for a doping concentration of 1.1%. In first-order DFB operation the threshold value could be further lowered to 320nJ∕cm2. These results render this material system an excellent candidate for stable and widely tunable lasers in the visible spectrum.
A comparison of underwater visual distance estimates made by scuba divers and a stereo-video system: implications for underwater visual census of reef fish abundance
Authors: Harvey Euan , Fletcher David , Shortis Mark R. , Kendrick Gary A.
Published: September 2004

Underwater visual census of reef fish by scuba divers is a widely used and useful technique for assessing the composition and abundance of reef fish assemblages, but suffers from several biases and errors. We compare the accuracy of underwater visual estimates of distance made by novice and experienced scientific divers and an underwater stereo-video system. We demonstrate the potential implications that distance errors may have on underwater visual census assessments of reef fish abundance. We also investigate how the accuracy and precision of scuba diver length estimates of fish is affected as distance increases. Distance was underestimated by both experienced (mean relative error = −11.7%, s.d. = 21.4%) and novice scientific divers (mean relative error = −5.0%, s.d. = 17.9%). For experienced scientific divers this error may potentially result in an 82% underestimate or 194% overestimate of the actual area censused, which will affect estimates of fish density. The stereo-video system also underestimated distance but to a much lesser degree (mean relative error = −0.9%, s.d. = 2.6%) and with less variability than the divers. There was no correlation between the relative error of length estimates and the distance of the fish away from the observer.
Age, growth and the potential for growth overfishing of spot (Leiostomus xanthurus) from the Chesapeake Bay, eastern USA
Authors: Piner Kevin R. , Jones Cynthia M.
Published: September 2004

Spot (Leiostomus xanthurus) are a popular commercial and sport fish in the Chesapeake Bay region (USA), but have not been managed with age-based models because of a lack of information on vital rates. This study determined that transversely sectioned otoliths were the most appropriate structure to age spot, and subsequently used those ages to estimate biological parameters and evaluate the potential for growth overfishing. Because spot are short-lived, this study explored estimating population parameters using both whole annulus counts and fractional ages. Although fractional ages may be more realistic, parameters estimated using fractions of a year should be interpreted with caution. Growth of spot was rapid (84% of length attained in the first year), the natural mortality rate was high (59% year−1), and the total mortality rate (natural + fishing) was very high (80–94% year−1). Spot maximised cohort biomass early in life (≈1 year) and were relatively impervious to growth overfishing. This study illustrates the difficulty in providing management advice for species that maximise cohort biomass about the same time as their first potential spawning event. This study also documents that high exploitation rates and size selective fishing gear probably affect estimates of population parameters.
The ecosystem effects of abalone fishing: a review
Authors: Jenkins Gregory P.
Published: September 2004

Although abalone fishing involves less damage to the habitat compared with other fishing methods, such as trawling and dredging and there are no problems of bycatch or discards, there are a number of issues relating to impact on the ecosystem. These issues include mechanical damage from anchors, catch bags and hoses, manipulation of predators and competitors by fishermen, and translocation of marine pests. The trophic impact of the removal of abalone would not be expected to be great, any impact may relate more to competition for space, for example, abalone may out-compete sea urchins for space when food is abundant. Therefore, the sea urchin population may be an ecological indicator of the impacts on the ecosystem of removing abalone. The data on the ecological impacts of abalone fishing are insufficient, and there have not been any direct experiments on the effects of varying abalone abundance on other ecosystem components. Recent studies on marine protected areas (MPAs) indicate that the ecological effects of fishing in reef systems may have had unexpected consequences. Abalone fishing offers a rare opportunity to trace the ecological effects of fishing, and to this end, a possible experimental framework is outlined.
Mitochondrial DNA reveals phylogenetic structuring and cryptic diversity in Australian freshwater macroinvertebrate assemblages
Authors: Baker Andrew M. , Hughes Jane M. , Dean John C. , Bunn Stuart E.
Published: September 2004

Freshwater catchments of south-east Australia possess generally rich and diverse macroinvertebrate faunas, although the genetic structuring of these assemblages is poorly known. In this study, we assessed mitochondrial phylogenetic structure within four genera of macroinvertebrates from the Sydney Water Supply Catchment, south-east Australia: Euastacus (parastacid crayfish), Cheumatopsyche (hydropsychid caddisflies), Atalophlebia (leptophlebiid mayflies) and Paratya (atyid shrimp), with a view to prioritising areas of high diversity for future conservation efforts. We found extremely divergent (≈4–19%) cytochrome c oxidase subunit I (COI) lineages within all surveyed groups, many of which corresponded to recognised taxa, although there was also evidence of cryptic species within three genera; Euastacus, Atalophlebia and Paratya. Distributions of these three genera were associated with high altitude streams, above dam impoundments. Our results have important implications for management of the Sydney Water Supply Catchment. Future disturbance in this region is likely to be high and priority should be directed towards preserving the diversity of fauna in these upland areas. This comparative phylogenetic approach may have value as a means to focus and direct conservation efforts in other areas supporting high biodiversity.
Domain swapping is a consequence of minimal frustration
Authors: Yang Sichun , Cho Samuel S. , Levy Yaakov , Cheung Margaret S. , Levine Herbert , Wolynes Peter G. , Onuchic José N.
Published: September 2004

The same energy landscape principles associated with the folding of proteins into their monomeric conformations should also describe how these proteins oligomerize into domain-swapped conformations. We tested this hypothesis by using a simplified model for the epidermal growth factor receptor pathway substrate 8 src homology 3 domain protein, both of whose monomeric and domain-swapped structures have been solved. The model, which we call the symmetrized Gō-type model, incorporates only information regarding the monomeric conformation in an energy function for the dimer to predict the domain-swapped conformation. A striking preference for the correct domain-swapped structure was observed, indicating that overall monomer topology is a main determinant of the structure of domain-swapped dimers. Furthermore, we explore the free energy surface for domain swapping by using our model to characterize the mechanism of oligomerization.
A nontransgenic mouse model shows inducible amyloid-β (Aβ) peptide deposition and elucidates the role of apolipoprotein E in the amyloid cascade
Authors: Dolev Iftach , Michaelson Daniel M.
Published: September 2004

The amyloid-β (Aβ) peptide, a major pathological hallmark of Alzheimer's disease (AD), undergoes a cascade of interactions resulting in the formation of soluble aggregates and their conversion in the brain to insoluble deposits and mature senile plaques. Furthermore, the apoE4 isoform of apolipoprotein E (apoE), which is the major genetic risk factor of AD, is associated with increased Aβ deposition. It is not known how the different Aβ aggregates in the amyloid cascade are formed, contribute to the pathogenesis of AD, or are affected by apoE4. To investigate the initial aggregation stages underlying the amyloid cascade
in vivo
and how apoE affects them, we examined the effects of prolonged inhibition and subsequent reactivation of the Aβ-degrading protease neprilysin on deposition, disaggregation, and fibrillization of Aβ in apoE-transgenic and control mice. In control mice, intracerebroventricular infusion of thiorphan, which inhibits neprilysin, induced Aβ42 and Aβ40 deposition and fibrillization. On termination of thiorphan treatment, the number of Aβ deposits decreased, whereas the fibrillar Aβ deposits were unaffected. Similar treatments in apoE-deficient mice and mice transgenic for human apoE4 or apoE3 revealed that apoE4 enhances specifically the nucleation and aggregation of immunopositive Aβ deposits and that reversible disaggregation of these deposits and their irreversible conversion to fibrillar deposits are stimulated similarly by the different apoE isoforms. Deposition of Aβ and its enhancement by apoE4 were accompanied by increased astrogliosis both far from and near the Aβ deposits, suggesting that astrogliosis might be triggered by both insoluble and soluble Aβ aggregates.
129Xe on Ir(111): NMR study of xenon on a metal single crystal surface
Authors: Jänsch H. J. , Gerhard P. , Koch M.
Published: September 2004

NMR experiments of129Xe adsorbed on an iridium single crystal surface are reported. Very high nuclear polarization (Pz≈ 0.7) makes the experiment possible. A coverage of less then one monolayer is investigated on the Ir(111) surface with an area of 0.8 cm2. The observed resonance line shifts are very large and highly anisotropic. We find σiso= 1,032 ± 11 ppm and σan= 291 ± 33 ppm, which are far above the typical range of physisorption. The highly ordered substrate leads to homogeneous conditions for the xenon atoms, as seen in the narrow linewidth of 20 ppm. Chemical shifts under physisorption conditions are not large enough to totally explain the results. Knight shift can clearly be identified as the cause of the findings. This shift shows the presence of conduction electrons of the metallic substrate at the xenon nucleus and thus the mixing of metallic and atomic states at the Fermi level. Such mixing is in accordance with recent Hartree–Fock and density functional calculations of similar van der Waals adsorption systems. Quantitative comparisons, however, fail completely. The size and ratio of σanand σisoare pure ground-state properties in a structurally simple system. They are accessible to theory and provide detailed local information that can serve as a benchmark for theory.
Comparative
PRKAR1A
genotype–phenotype analyses in humans with Carney complex and
prkar1a
haploinsufficient mice
Authors: Veugelers Mark , Wilkes David , Burton Kimberly , McDermott Deborah A. , Song Yan , Goldstein Marsha M. , La Perle Krista , Vaughan Carl J. , O'Hagan Art , Bennett Kenneth R. , Meyer Beat J. , Legius Eric , Karttunen Mervi , Norio Reijo , Kaariainen Helena , Lavyne Michael , Neau Jean-Philippe , Richter Gert , Kirali Kaan , Farnsworth Alan , Stapleton Karen , Morelli Peter , Takanashi Yoshinori , Bamforth John-Steven , Eitelberger Franz , Noszian Irene , Manfroi Waldimiro , Powers James , Mochizuki Yoshihiko , Imai Tsuneo , Ko Gary T. C. , Driscoll Deborah A. , Goldmuntz Elizabeth , Edelberg Jay M. , Collins Amanda , Eccles Diana , Irvine Alan D. , McKnight G. Stanley , Basson Craig T.
Published: September 2004

Carney complex (CNC) is a familial multiple neoplasia syndrome characterized by cardiac and extracardiac myxomas in the setting of spotty skin pigmentation and endocrinopathy. We previously identified
PRKAR1A
(regulatory subunit 1α of protein kinase A) mutations in CNC. Mutational analyses of the
PRKAR1A
gene in 51 unrelated CNC probands now detect mutations in 65%. All mutations, except for one unique missense mutation, lead to
PRKAR1A
haploinsufficiency. Therefore, we studied the consequences of
prkar1a
haploinsufficiency in mice. Although we did not observe cardiac myxomas or altered pigmentation in
prkar1a
+/–
mice, we did observe some phenotypes similar to CNC, including altered heart rate variability. Moreover,
prkar1a
+/–
mice exhibited a marked propensity for extracardiac tumorigenesis. They developed sarcomas and hepatocellular carcinomas. Sarcomas were frequently associated with myxomatous differentiation. Tumors from
prkar1a
+/–
mice did not exhibit
prkar1a
loss of heterozygosity. Thus, we conclude that although PRKAR1A haploinsufficiency does predispose to tumorigenesis, distinct secondary genetic events are required for tumor formation.
L-SIGN (CD209L) and DC-SIGN (CD209) mediate transinfection of liver cells by hepatitis C virus
Authors: Cormier Emmanuel G. , Durso Robert J. , Tsamis Fotini , Boussemart Lise , Manix Catherine , Olson William C. , Gardner Jason P. , Dragic Tatjana
Published: September 2004

Target cell tropism of enveloped viruses is regulated by interactions between viral and cellular factors during transmission, dissemination, and replication within the host. Binding of viral envelope glycoproteins to specific cell-surface receptors determines susceptibility to viral entry. However, a number of cell-surface molecules bind viral envelope glycoproteins without mediating entry. Instead, they serve as capture receptors that disseminate viral particles to target organs or susceptible cells. We and others recently demonstrated that the C type lectins L-SIGN and DC-SIGN capture hepatitis C virus (HCV) by specific binding to envelope glycoprotein E2. In this study, we use an entry assay to demonstrate that HCV pseudoviruses captured by L-SIGN+ or DC-SIGN+ cells efficiently transinfect adjacent human liver cells. Virus capture and transinfection require internalization of the SIGN–HCV pseudovirus complex.In vivo, L-SIGN is largely expressed on endothelial cells in liver sinusoids, whereas DC-SIGN is expressed on dendritic cells. Capture of circulating HCV particles by these SIGN+ cells may facilitate virus infection of proximal hepatocytes and lymphocyte subpopulations and may be essential for the establishment of persistent infection.
Dissection of the role of MHC class II A and E genes in autoimmune susceptibility in murine lupus models with intragenic recombination
Authors: Zhang Danqing , Fujio Keishi , Jiang Yi , Zhao Jingyuan , Tada Norihiro , Sudo Katsuko , Tsurui Hiromichi , Nakamura Kazuhiro , Yamamoto Kazuhiko , Nishimura Hiroyuki , Shira Toshikazu , Hirose Sachiko
Published: September 2004

Systemic lupus erythematosus (SLE) is a multigenic autoimmune disease, and the major histocompatibility complex (MHC) class II polymorphism serves as a key genetic element. In SLE-prone (NZB × NZW)F1mice, the MHC H-2d/zheterozygosity (H-2dof NZB and H-2zof NZW) has a strong impact on disease; thus, congenic H-2d/dhomozygous F1mice do not develop severe disease. In this study, we usedEa-deficient intra-H-2 recombination to establish Ad/d-congenic (NZB × NZW)F1mice, with or without E molecule expression, and dissected the role of class II A and E molecules. Here we found that Ad/dhomozygous F1mice lacking E molecules developed severe SLE similar to that seen in wild-type F1 mice, including lupus nephritis, autoantibody production, and spontaneously occurring T cell activation. Additional evidence revealed that E molecules prevent the disease in a dose-dependent manner; however, the effect is greatly influenced by the haplotype of A molecules, because wild-type H-2d/zF1mice develop SLE, despite E molecule expression. Studies on the potential of dendritic cells to present a self-antigen chromatin indicated that dendritic cells from wild-type F1mice induced a greater response of chromatin-specific T cells than did those from Ad/dF1mice, irrespective of the presence or absence of E molecules, suggesting that the self-antigen presentation is mediated by A, but not by E, molecules. Our mouse models are useful for analyzing the molecular mechanisms by which MHC class II regions regulate the process of autoimmune responses.
A quenchable superhard carbon phase synthesized by cold compression of carbon nanotubes
Authors: Wang Zhongwu , Zhao Yusheng , Tait Kimberly , Liao Xiaozhou , Schiferl David , Zha Changsheng , Downs Robert T. , Qian Jiang , Zhu Yuntian , Shen Tongde
Published: September 2004

A quenchable superhard high-pressure carbon phase was synthesized by cold compression of carbon nanotubes. Carbon nanotubes were placed in a diamond anvil cell, and x-ray diffraction measurements were conducted to pressures of ≈100 GPa. A hexagonal carbon phase was formed at ≈75 GPa and preserved at room conditions. X-ray and transmission electron microscopy electron diffraction, as well as Raman spectroscopy at ambient conditions, explicitly indicate that this phase is a
sp
3
-rich hexagonal carbon polymorph, rather than hexagonal diamond. The cell parameters were refined to a
0
= 2.496(4) Å, c
0
= 4.123(8) Å, and V
0
= 22.24(7) Å
3
. There is a significant ratio of defects in this nonhomogeneous sample that contains regions with different stacking faults. In addition to the possibly existing amorphous carbon, an average density was estimated to be 3.6 ± 0.2 g/cm
3
, which is at least compatible to that of diamond (3.52 g/cm
3
). The bulk modulus was determined to be 447 GPa at fixed K′≡4, slightly greater than the reported value for diamond of ≈440–442 GPa. An indented mark, along with radial cracks on the diamond anvils, demonstrates that this hexagonal carbon is a superhard material, at least comparable in hardness to cubic diamond.
Rb is required for progression through myogenic differentiation but not maintenance of terminal differentiation
Authors: Huh Michael S. , Parker Maura H. , Scimè Anthony , Parks Robin , Rudnicki Michael A.
Published: September 2004

To investigate the requirement for pRb in myogenic differentiation, a floxed Rb allele was deleted either in proliferating myoblasts or after differentiation. Myf5-Cre mice, lacking pRb in myoblasts, died immediately at birth and exhibited high numbers of apoptotic nuclei and an almost complete absence of myofibers. In contrast, MCK-Cre mice, lacking pRb in differentiated fibers, were viable and exhibited a normal muscle phenotype and ability to regenerate. Induction of differentiation of Rb-deficient primary myoblasts resulted in high rates of apoptosis and a total inability to form multinucleated myotubes. Upon induction of differentiation, Rb-deficient myoblasts up-regulated myogenin, an immediate early marker of differentiation, but failed to down-regulate Pax7 and exhibited growth in low serum conditions. Primary myoblasts in which Rb was deleted after expression of differentiated MCK-Cre formed normal multinucleated myotubes that did not enter S-phase in response to serum stimulation. Therefore, Rb plays a crucial role in the switch from proliferation to differentiation rather than maintenance of the terminally differentiated state.
Transcription-dependent spatial arrangements of CFTR and adjacent genes in human cell nuclei
Authors: Zink Daniele , Amaral Margarida D. , Englmann Andreas , Lang Susanne , Clarke Luka A. , Rudolph Carsten , Alt Felix , Luther Kathrin , Braz Carla , Sadoni Nicolas , Rosenecker Joseph , Schindelhauer Dirk
Published: September 2004

We investigated in different human cell types nuclear positioning and transcriptional regulation of the functionally unrelated genes GASZ, CFTR, and CORTBP2, mapping to adjacent loci on human chromosome 7q31. When inactive, GASZ, CFTR, and CORTBP2 preferentially associated with the nuclear periphery and with perinuclear heterochromatin, whereas in their actively transcribed states the gene loci preferentially associated with euchromatin in the nuclear interior. Adjacent genes associated simultaneously with these distinct chromatin fractions localizing at different nuclear regions, in accordance with their individual transcriptional regulation. Although the nuclear localization of CFTR changed after altering its transcription levels, the transcriptional status of CFTR was not changed by driving this gene into a different nuclear environment. This implied that the transcriptional activity affected the nuclear positioning, and not vice versa. Together, the results show that small chromosomal subregions can display highly flexible nuclear organizations that are regulated at the level of individual genes in a transcription-dependent manner.
Mathematical modeling reveals threshold mechanism in CD95-induced apoptosis
Authors: Bentele M. , Lavrik I. , Ulrich M. , Stößer S. , Heermann D.W. , Kalthoff H. , Krammer P.H. , Eils R.
Published: September 2004

Mathematical modeling is required for understanding the complex behavior of large signal transduction networks. Previous attempts to model signal transduction pathways were often limited to small systems or based on qualitative data only. Here, we developed a mathematical modeling framework for understanding the complex signaling behavior of CD95(APO-1/Fas)-mediated apoptosis. Defects in the regulation of apoptosis result in serious diseases such as cancer, autoimmunity, and neurodegeneration. During the last decade many of the molecular mechanisms of apoptosis signaling have been examined and elucidated. A systemic understanding of apoptosis is, however, still missing. To address the complexity of apoptotic signaling we subdivided this system into subsystems of different information qualities. A new approach for sensitivity analysis within the mathematical model was key for the identification of critical system parameters and two essential system properties: modularity and robustness. Our model describes the regulation of apoptosis on a systems level and resolves the important question of a threshold mechanism for the regulation of apoptosis.
Myotubes differentiate optimally on substrates with tissue-like stiffness
Authors: Engler Adam J. , Griffin Maureen A. , Sen Shamik , Bönnemann Carsten G. , Sweeney H. Lee , Discher Dennis E.
Published: September 2004

Contractile myocytes provide a test of the hypothesis that cells sense their mechanical as well as molecular microenvironment, altering expression, organization, and/or morphology accordingly. Here, myoblasts were cultured on collagen strips attached to glass or polymer gels of varied elasticity. Subsequent fusion into myotubes occurs independent of substrate flexibility. However, myosin/actin striations emerge later only on gels with stiffness typical of normal muscle (passive Young's modulus, E ∼12 kPa). On glass and much softer or stiffer gels, including gels emulating stiff dystrophic muscle, cells do not striate. In addition, myotubes grown on top of a compliant bottom layer of glass-attached myotubes (but not softer fibroblasts) will striate, whereas the bottom cells will only assemble stress fibers and vinculin-rich adhesions. Unlike sarcomere formation, adhesion strength increases monotonically versus substrate stiffness with strongest adhesion on glass. These findings have major implications for in vivo introduction of stem cells into diseased or damaged striated muscle of altered mechanical composition.
Functional interaction between BLM helicase and 53BP1 in a Chk1-mediated pathway during S-phase arrest
Authors: Sengupta Sagar , Robles Ana I. , Linke Steven P. , Sinogeeva Natasha I. , Zhang Ran , Pedeux Remy , Ward Irene M. , Celeste Arkady , Nussenzweig André , Chen Junjie , Halazonetis Thanos D. , Harris Curtis C.
Published: September 2004

Bloom's syndrome is a rare autosomal recessive genetic disorder characterized by chromosomal aberrations, genetic instability, and cancer predisposition, all of which may be the result of abnormal signal transduction during DNA damage recognition. Here, we show that BLM is an intermediate responder to stalled DNA replication forks. BLM colocalized and physically interacted with the DNA damage response proteins 53BP1 and H2AX. Although BLM facilitated physical interaction between p53 and 53BP1, 53BP1 was required for efficient accumulation of both BLM and p53 at the sites of stalled replication. The accumulation of BLM/53BP1 foci and the physical interaction between them was independent of γ-H2AX. The active Chk1 kinase was essential for both the accurate focal colocalization of 53BP1 with BLM and the consequent stabilization of BLM. Once the ATR/Chk1- and 53BP1-mediated signal from replicational stress is received, BLM functions in multiple downstream repair processes, thereby fulfilling its role as a caretaker tumor suppressor.
YidC family members are involved in the membrane insertion, lateral integration, folding, and assembly of membrane proteins
Authors: Dalbey Ross E. , Kuhn Andreas
Published: September 2004

Members of the YidC family exist in all three domains of life, where they control the assembly of a large variety of membrane protein complexes that function as transporters, energy devices, or sensor proteins. Recent studies in bacteria have shown that YidC functions on its own as a membrane protein insertase independent of the Sec protein–conducting channel. YidC can also assist in the lateral integration and folding of membrane proteins that insert into the membrane via the Sec pathway.
Direct Sequencing of SARS-Coronavirus S and N Genes from Clinical Specimens Shows Limited Variation
Authors: Tong Suxiang , Lingappa Jairam R. , Chen Qi , Shu Bo , LaMonte Ashley C. , Cook Byron T. , Birge Charryse , Wang Chern Shur-wern , Liu Xin , Galloway Renee , Le Quynh Mai , Wai Fu Ng , Yang Jyh-Yuan , Butany Jagdish , Comer James A. , Monroe Stephan S. , Beard Suzanne R. , Ksiazek Thomas G. , Erdman Dean , Rota Paul A. , Pallansch Mark A. , Anderson Larry J.
Published: September 2004

Severe acute respiratory syndrome-associated coronavirus (SARS-CoV) emerged, in November 2002, as a novel agent causing severe respiratory illness. To study sequence variation in the SARS-CoV genome, we determined the nucleic acid sequence of the S and N genes directly from clinical specimens from 10 patients—1 specimen with no matched SARS-CoV isolate, from 2 patients; multiple specimens from 3 patients; and matched clinical-specimen/ cell-culture-isolate pairs from 6 patients. We identified 3 nucleotide substitutions that were most likely due to natural variation and 2 substitutions that arose after cell-culture passage of the virus. These data demonstrate the overall stability of the S and N genes of SARS-CoV over 3 months during which a minimum of 4 generations for transmission events occurred. These findings are a part of the expanding investigation of the evolution of how this virus adapts to a new host.
Neutralizing Antibodies in Patients with Severe Acute Respiratory Syndrome-Associated Coronavirus Infection
Authors: Yuchun Nie , Guangwen Wang , Xuanling Shi , Hong Zhang , Yan Qiu , Zhongping He , Wei Wang , Gewei Lian , Xiaolei Yin , Liying Du , Lili Ren , Jianwei Wang , Xiong He , Taisheng Li , Hongkui Deng , Mingxiao Ding
Published: September 2004

Background . Severe acute respiratory syndrome (SARS)-associated coronavirus (SARS-CoV) is the principal etiologic agent of SARS. We analyzed serum samples obtained from 623 patients with SARS in Beijing, to determine whether infection with SARS-CoV can elicit neutralizing antibodies (NAbs).

Methods . We developed a highly sensitive and safe neutralization assay using the SARS-CoV pseudotyped virus and used this assay to determine the titers of the NAbs in serum samples from patients with SARS.

Results . We found that 85.9% of serum samples contained NAbs against SARS-CoV and that most of the NAb activities could be attributed to immunoglobulin G. The NAbs became detectable first at 5–10 days after the onset of symptoms, and their levels peaked at 20–30 days and then were sustained for >150 days. The serum samples could neutralize the pseudotype particles bearing the spike glycoproteins from different SARS-CoV strains, suggesting that the NAbs to SARS-CoV were broadly reactive.

Conclusions . NAbs to SARS-CoV are broadly elicited in patients with SARS and, according to their kinetics, may correlate with viral load during the early stages of the disease. These results suggest that it is possible to develop effective vaccines against SARS and that NAbs provide a potential strategy for treating patients with SARS.
Septin Ring Assembly Requires Concerted Action of Polarisome Components, a PAK Kinase Cla4p, and the Actin Cytoskeleton inSaccharomyces cerevisiae
Authors: Kadota Jun , Yamamoto Takaharu , Yoshiuchi Shiro , Bi Erfei , Tanaka Kazuma
Published: September 2004

Septins are filament-forming proteins that function in cytokinesis in a wide variety of organisms. In budding yeast, the small GTPase Cdc42p triggers the recruitment of septins to the incipient budding site and the assembly of septins into a ring. We herein report that Bni1p and Cla4p, effectors of Cdc42p, are required for the assembly of the septin ring during the initiation of budding but not for its maintenance after the ring converts to a septin collar. In bni1Δ cla4-75-td mutant, septins were recruited to the incipient budding site. However, the septin ring was not assembled, and septins remained at the polarized growing sites. Bni1p, a formin family protein, is a member of the polarisome complex with Spa2p, Bud6p, and Pea2p. All spa2Δ cla4-75-td, bud6Δ cla4-75-td, and pea2Δ cla4-75-td mutants showed defects in septin ring assembly. Bni1p stimulates actin polymerization for the formation of actin cables. Point mutants of BNI1 that are specifically defective in actin cable formation also exhibited septin ring assembly defects in the absence of Cla4p. Consistently, treatment of cla4Δ mutant with the actin inhibitor latrunculin A inhibited septin ring assembly. Our results suggest that polarisome components and Cla4p are required for the initial assembly of the septin ring and that the actin cytoskeleton is involved in this process.
Stable and Dynamic Axes of Polarity Use Distinct Formin Isoforms in Budding Yeast
Authors: Pruyne David , Gao Lina , Bi Erfei , Bretscher Anthony
Published: September 2004

Bud growth in yeast is guided by myosin-driven delivery of secretory vesicles from the mother cell to the bud. We find transport occurs along two sets of actin cables assembled by two formin isoforms. The Bnr1p formin assembles cables that radiate from the bud neck into the mother, providing a stable mother-bud axis. These cables also depend on septins at the neck and are required for efficient transport from the mother to the bud. The Bni1p formin assembles cables that line the bud cortex and target vesicles to varying locations in the bud. Loss of these cables results in morphological defects as vesicles accumulate at the neck. Assembly of these cables depends on continued polarized secretion, suggesting vesicular transport provides a positive feedback signal for Bni1p activation, possibly by rho-proteins. By coupling different formin isoforms to unique cortical landmarks, yeast uses common cytoskeletal elements to maintain stable and dynamic axes in the same cell.
The Fission Yeast Kinetochore Component Spc7 Associates with the EB1 Family Member Mal3 and Is Required for Kinetochore–Spindle Association
Authors: Kerres Anne , Vietmeier-Decker Corina , Ortiz Jennifer , Karig Inga , Beuter Christoph , Hegemann Johannes , Lechner Johannes , Fleig Ursula
Published: September 2004

A critical aspect of mitosis is the interaction of the kinetochore with spindle microtubules. Fission yeast Mal3 is a member of the EB1 family of microtubule plus-end binding proteins, which have been implicated in this process. However, the Mal3 interaction partner at the kinetochore had not been identified. Here, we show that the mal3 mutant phenotype can be suppressed by the presence of extra Spc7, an essential kinetochore protein associated with the central centromere region. Mal3 and Spc7 interact physically as both proteins can be coimmunoprecipitated. Overexpression of a Spc7 variant severely compromises kinetochore–microtubule interaction, indicating that the Spc7 protein plays a role in this process. Spc7 function seems to be conserved because, Spc105, a Saccharomyces cerevisiae homolog of Spc7, identified by mass spectrometry as a component of the conserved Ndc80 complex, can rescue mal3 mutant strains.
CCN2 (Connective Tissue Growth Factor) Promotes Fibroblast Adhesion to Fibronectin
Authors: Chen Yunliang , Abraham David J. , Shi-wen Xu , Pearson Jeremy D. , Black Carol M. , Lyons Karen M. , Leask Andrew
Published: September 2004

In vivo, CCN2 (connective tissue growth factor) promotes angiogenesis, osteogenesis, tissue repair, and fibrosis, through largely unknown mechanisms. In vitro, CCN2 promotes cell adhesion in a variety of systems via integrins and heparin sulfate proteoglycans (HSPGs). However, the physiological relevance of CCN2-mediated cell adhesion is unknown. Here, we find that HSPGs and the mitogen-activated protein kinase kinase/extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase cascade are required for adult human dermal fibroblasts to adhere to CCN2. Endogenous CCN2 directly binds fibronectin and the fibronectin receptors integrins α4 β1 and α5 and syndecan 4. Using Ccn2-/- mouse embryonic fibroblasts, we show that loss of endogenous CCN2 results in impaired spreading on fibronectin, delayed α-smooth muscle actin stress fiber formation, and reduced ERK and focal adhesion kinase phosphorylation. These results suggest that a physiological role of CCN2 is to potentiate the ability of fibroblasts to spread on fibronectin, which may be important in modulating fibroblast adhesion to the provisional matrix during tissue development and wound healing. These results are consistent with the notion that a principal function of CCN2 is to modulate receptor/ligand interactions in vivo.
On the Choice of Appropriate Development
Strategy: Insights Gained from CGE Modelling of
the Mozambican Economy
Authors: Jensen Henning Tarp , Tarp Finn
Published: September 2004

This paper uses a 1997 Computable General Equilibrium (CGE) model to analyse three strategies which Mozambique can pursue in furthering a sustainable development process. They include (i) agriculture-first, (ii) agricultural-development-led-industrialisation (ADLI) and (iii) a primary-sector export-oriented strategy. ADLI dominates the two other approaches and the distributional implications of ADLI are attractive. We also find that there are important synergy effects to be reaped from balanced agricultural and agro-industrial development, and the primarysector export-oriented strategy represents a potentially significant set of complementary policies. Finally, the importance of taking structural differences among household groupings into account when formulating comprehensive pro-equity and anti-poverty development strategies is prominent.
Vascular endothelial growth factor‐C gene therapy restores lymphatic flow across incision wounds
Authors: Saaristo Anne , Tammela Tuomas , Timonen Jari , Yla-Herttuala Seppo , Tukiainen Erkki , Asko-Seljavaara Sirpa , Alitalo Kari
Published: September 2004

Edema and insufficient blood perfusion are common problems in reconstructive surgery. The blood vasculature is reconstructed in microvascular flaps, whereas lymphatic vessel function is lost after surgical incision. Here, we demonstrate that vascular endothelial growth factor C (VEGF‐C) gene transfer can be used to reconstruct a lymphatic vessel network severed by incision of skin flaps. We used adenoviral VEGF‐C gene transfer at the edges of epigastric skin flaps in mice. Our results show that VEGF‐C gene expression results in the formation of anastomoses between the lymphatic vessels of the skin flap and the surrounding lymphatic vasculature. Some spontaneous lymphangiogenesis also took place in the control mice, but the lymphatic vessels generated remained nonfunctional even 2 months postoperatively. In contrast, the VEGF‐C treated mice demonstrated persistent lymphatic vessel function during the 2 month follow‐up despite the transient nature of the adenoviral VEGF‐C gene expression. The restoration of lymphatic function by VEGF‐C in skin flaps provides new tools to promote vascular perfusion and to reduce tissue edema in skin and muscle flaps. These results have important implications for the prevention and treatment of surgically induced secondary lymphedema.
Identification of insulin receptor substrate proteins as key molecules for the TβR‐V/LRP‐1‐mediated growth inhibitory signaling cascade in epithelial and myeloid cells
Authors: Shian Huang Shuan , M. Leal Sandra , Chen Chun-Lin , Liu I-Hua , San Huang Jung
Published: September 2004

The type V TGF‐β receptor (TβR‐V) mediates IGF‐independent growth inhibition by IGFBP‐3 and mediates growth inhibition by TGF‐β 1 in concert with the other TGF‐β receptor types. TβR‐V was recently found to be identical to LRP‐1. Here we find that insulin and (Q3A4Y15L16) IGF‐I (an IGF‐I analog that has a low affinity for IGFBP‐3) antagonize growth inhibition by IGFBP‐3 in mink lung epithelial cells (Mv1Lu cells) stimulated by serum. In these cells, IGFBP‐3 induces serine‐specific dephosphorylation of IRS‐1 and IRS‐2. The IGFBP‐3‐induced dephosphorylation of IRS‐2 is prevented by cotreatment of cells with insulin, (Q3A4Y15L16) IGF‐I, or TβR‐V/LRP‐1 antagonists. The magnitude of the IRS‐2 dephosphorylation induced by IGFBP‐3 positively correlates with the degree of growth inhibition by IGFBP‐3 in Mv1Lu cells and mutant cells derived from Mv1Lu cells. Stable transfection of murine 32D myeloid cells (which lack endogenous IRS proteins and are insensitive to growth inhibition by IGFBP‐3) with IRS‐1 or IRS‐2 cDNA confers sensitivity to growth inhibition by IGFBP‐3; this IRS‐mediated growth inhibition can be completely reversed by insulin in 32D cells stably expressing IRS‐2 and the insulin receptor. These results suggest that IRS‐1 and IRS‐2 are key molecules for the TβR‐V/LRP‐1‐mediated growth inhibitory signaling cascade.
Galectin‐3/AGE‐receptor 3 knockout mice show accelerated AGE‐induced glomerular injury: evidence for a protective role of galectin‐3 as an AGE receptor
Authors: Iacobini Carla , Menini Stefano , Oddi Giovanna , Ricci Carlo , Amadio Lorena , Pricci Flavia , Olivieri Antonella , Sorcini Mariella , Di Mario Umberto , Pesce Carlo , Pugliese Giuseppe
Published: September 2004

We previously showed that mice lacking galectin‐3/AGE‐receptor 3 develop accelerated diabetic glomerulopathy. To further investigate the role of galectin‐3/AGE‐receptor function in the pathogenesis of diabetic renal disease, galectin‐3 knockout (KO) and coeval wild‐type (WT) mice were injected for 3 months with 30 μg/day of Nε‐carboxymethyllysine (CML)‐modified or unmodified mouse serum albumin (MSA). Despite receiving equal doses of CML, KO had higher circulating and renal AGE levels and showed more marked renal functional and structural changes than WT mice, with significantly higher proteinuria, albuminuria, glomerular, and mesangial area and glomerular sclerosis index. Renal 4‐hydroxy‐2‐nonenal content and NFκB activation were also more pronounced in KO‐CML vs. WT‐CML. Kidney mRNA levels of fibronectin, laminin, collagen IV, and TGF‐β were up‐regulated, whereas those of matrix metalloproteinase‐2 and ‐14 were down‐regulated, again more markedly in KO‐CML than WT‐CML mice. Basal and CML‐induced RAGE and 80K‐H mRNA levels were higher in KO vs. WT mice. MSA injection did not produce any significant effect in both genotypes. The association of galectin‐3 ablation with enhanced susceptibility to AGE‐induced renal disease, increased AGE levels and signaling, and altered AGE‐receptor pattern indicates that galectin‐3 is operating in vivo as an AGE receptor to afford protection toward AGE‐dependent tissue injury.
Sweet Liking, Novelty Seeking, and Gender Predict Alcoholic Status
Authors: Kampov‐Polevoy Alexey B. , Eick C , Boland G , Khalitov E , Crews F T.
Published: September 2004

Background:The relationship between a hedonic response to sweet taste and a propensity to excessive alcohol drinking is supported by both animal and human studies. There is evidence indicating that the tendency to rate more concentrated sweet solutions as the most pleasurable (i.e., sweet liking) is associated with the genetic vulnerability to alcoholism. However, sweet liking by itself is insufficient to predict the alcoholic status of the individual. Our previous study indicated that alcoholic status can be predicted by a combination of hedonic response to sweet taste and personality profile as measured by the Tridimensional Personality Questionnaire (TPQ). This study was designed to further test this hypothesis.

Methods:Participants were 165 patients admitted to a residential treatment program for the treatment of alcoholism, drug dependence and/or interpersonal problems secondary to substance‐abusing family members. In addition to a routine medical examination, on the 24th day after admission, patients completed the TPQ, the standard sweet taste test was conducted, and paternal family history of alcoholism was evaluated.

Results:Sweet liking was strongly associated with a paternal history of alcoholism. The odds of receiving an alcohol dependence diagnosis were shown to increase, on the average, by 11% for every one‐point increase in the TPQ novelty‐seeking score in sweet‐liking but not in sweet‐disliking subjects. Gender contributed independently to the probability of alcohol dependence, with males exhibiting higher rates of alcoholism than females.

Conclusions:These findings support the hypothesis that a hedonic response to sweet taste is associated with a genetic risk for alcoholism. Alcoholic status may be predicted by a combination of sweet liking, the TPQ novelty‐seeking score, and gender in a mixed group of alcoholic, polysubstance‐dependent, and psychiatric patients.
Effects of Naltrexone and Nalmefene on Subjective Response to Alcohol Among Non‐Treatment‐Seeking Alcoholics and Social Drinkers
Authors: Drobes David J. , Anton Raymond F. , Thomas Suzanne E. , Voronin Konstantin
Published: September 2004

Background: Despite the relative success of opiate antagonist medication within controlled clinical trials for alcoholism, laboratory studies have not fully examined potential mechanisms for their efficacy in alcohol‐dependent persons. The present study evaluated the impact of naltrexone and nalmefene on craving and subjective effects after a moderate alcohol dose among non‐treatment‐seeking alcoholics (n = 125) and social drinkers (n = 90).

Methods: Participants were randomly assigned to receive placebo, naltrexone (titrated to 50 mg/day), or nalmefene (titrated to 40 mg/day) for seven days before an alcohol challenge clinical laboratory session. During the clinical laboratory session, a drink of alcohol (0.4 mg/kg for men, 0.34 mg/kg for women) was provided in a bar‐like setting. The effects of the alcohol dose on subjective craving, stimulation, and sedation were measured before having free access to alcohol.

Results: Alcoholics reported higher levels of craving than social drinkers before and after the drink as well as higher levels of alcohol‐induced stimulation. Both opiate antagonist medications suppressed initial increases in craving and stimulation.

Conclusions: These findings demonstrate that both naltrexone and nalmefene are associated with reduced alcohol‐induced craving and stimulation among alcoholics who are not actively attempting to reduce drinking. These data provide insights into potential mechanisms that may underlie opiate antagonists’ effects in the context of treatment.
Ethanol Inhibits Gap‐Junctional Coupling Between P19 Cells
Authors: Wentlandt Kirsten , Kushnir Moshe , Naus Christian C. G. , Carlen Peter L.
Published: September 2004

Background: Gap junctions are plaques of multiple intercellular channels that connect the cytoplasm of adjacent cells. They provide both electrical and metabolic coupling and are an essential element in normal growth, development, and physiology. Little research exists on the relationship between alcohol administration and gap‐junctional function or expression. This study looks at the function and expression of gap junctions after incubation and withdrawal of ethanol with P19 cell cultures.

Methods: Gap‐junctional communication was assessed after 24 and 48 hr of exposure to 20 and 40 mM ethanol and after a 24‐hr withdrawal period. The seeding technique was used, and diacyl‐3,3′‐indocarbocyanine iodide/calcein–stained donor cells were seeded on an unstained monolayer and then reviewed by confocal microscope and counted by flow cytometry. Analysis of connexin (Cx) proteins was performed by Western blot, gel electrophoresis, and immunoblots with antibodies for Cx26 and Cx43.

Results: All treatment regimens produced similar results, reducing dye coupling by more than 50% without recovery after a 24‐hr withdrawal period. Exposing the cells to 20 mM ethanol for 48 hr did not significantly change the levels of Cx26 protein, but ethanol significantly decreased the levels of Cx43 in cultured P19 cells.

Conclusions: This study illustrates that ethanol can inhibit gap‐junction function in the P19 cell line. Chronic exposure to 20 mM ethanol selectively decreased the levels of Cx43 protein in the membrane fraction of the cell cultures.
Toward the Attainment of Low‐Risk Drinking Goals: A 10‐Year Progress Report
Authors: Dawson Deborah A. , Grant Bridget F. , Stinson Frederick S. , Chou Patricia S.
Published: September 2004

Background: The Healthy People 2010 goals include reducing the proportion of U.S. adults whose alcohol consumption exceeds recommended daily and weekly limits, relative to baseline levels observed in 1991–1992. To date, there has been no assessment of initial progress toward attaining these goals.

Methods: Consumption data from the 1991–1992 National Longitudinal Alcohol Epidemiology Survey (n= 42,862) and the 2001–2003 National Epidemiologic Survey on Alcohol and Related Conditions (n= 43,093) were used to evaluate the trend in the proportion of U.S. adults adhering to and exceeding recommended drinking limits. These included weekly limits of no more than 14 standard drinks for men and no more than 7 standard drinks for women and daily limits of no more than 4 standard drinks for men and 3 standard drinks for women. The percentages exceeding the limits are compared for the two time periods, for the total adult population and sociodemographic subgroups, and the association between risk drinking and sociodemographic characteristics is disaggregated into a series of conditional odds ratios.

Results: The proportion of U.S. adults classified as regular drinkers whose intake exceeded recommended daily or weekly limits declined from 32.1% to 29.3% in the 10‐year period. The reduction in risk drinking occurred solely among persons who exceeded the daily drinking limits less than once a week but did not exceed the weekly limits. There was a very small but significant increase in the proportion of adults exceeding the weekly limits, from 9.4% to 10.3%. Reduction of sociodemographic disparities in adherence to drinking limits was limited.

Conclusions: Progress to date is limited and may reflect changes in population composition rather than changes in drinking habits. Attainment of Healthy People goals and reduction of disparities in risk drinking will require sustained effort and more targeted prevention programs.