bluuebunny/crossref_metadata_2025 huggingface dataset:
The origin of cyanobacteria in Antarctic sea ice: marine or freshwater?
Authors: Koh Eileen Y. , Cowie Rebecca O. M. , Simpson Aimee M. , O'Toole Ronan , Ryan Ken G.
Published: April 2012

Cyanobacteria play an important role in the primary productivity of many ecosystems and are dominant in non‐marine polar environments. Apart from detecting low levels of cyanobacteria‐like pigments in the Southern Ocean, little effort has been spent in trying to elucidate Cyanobacteria in Antarctic sea ice. Here, we report the first use of culture, microscope, microarray and molecular techniques to show that marine Cyanobacteria are rare or absent in sea ice. Our infrequent positive signals were most closely related to freshwater Cyanobacteria from neighbouring terrestrial sources, which illustrates our techniques were sensitive enough to find sea‐ice cyanobacteria if they were present. It is still possible that minute quantity of marine cyanobacteria may exist in sea ice and do not contribute significantly to the polar marine ecosystems.
Properties of original impactors estimated from three‐dimensional analysis of whole Stardust tracks
Authors: GREENBERG Michael , EBEL Denton S.
Published: April 2012

Abstract– The Stardust mission captured comet Wild 2 particles in aerogel at 6.1 km s−1. We performed high‐resolution three‐dimensional imaging and X‐ray fluorescence mapping of whole cometary tracks in aerogel. We present the results of a survey of track structures using laser scanning confocal microscopy, including measurements of track volumes, entry hole size, and cross‐sectional profiles. We compare various methods for measuring track parameters. We demonstrate a methodology for discerning hypervelocity particle ablation rates using synchrotron‐based X‐ray fluorescence, combined with mass and volume estimates of original impactors derived from measured track properties. Finally, we present a rough framework for reconstruction of original impactor size, and volume of volatilized material, using our measured parameters. The bulk of this work is in direct support of nondestructive analysis and identification of cometary grains in whole tracks, and its eventual application to the reconstruction of the size, shape, porosity, and chemical composition of whole Stardust impactors.
Sulfur four isotope NanoSIMS analysis of comet‐81P/Wild 2 dust in impact craters on aluminum foil C2037N from NASA’s Stardust mission
Authors: HECK Philipp R. , HOPPE Peter , HUTH Joachim
Published: April 2012

Abstract– We present NanoSIMS four‐isotope S analyses of 24 comet Wild 2 dust impact residues in craters on aluminum foil C2037N returned by NASA’s Stardust mission. Except for one sample, all impact residues have normal S isotopic compositions within 2σ uncertainties of at least two S isotope ratios. This implies that most S‐rich Wild 2 dust impactors formed in the solar system. Instrumental isotope fractionation due to sample topography is the main contribution to our analytical uncertainty. One impact crater residue shows small anomalies of δ33S = −57 ± 17‰, and δ34S = −41 ± 17‰ (1σ uncertainties). Although this could be simply a statistical outlier or the fingerprint of a chemical isotope fractionation it is also possible that the observed anomaly results from the mixture of a cometary FeS particle with a small (150 nm diam.) presolar FeS supernova grain. This would translate into a presolar sulfide abundance of approximately 200 ppm.
In-vivo pharmacokinetics, tissue distribution and anti-tumour effect of hydroxycamptothecin delivered in oil-in-water submicron emulsions
Authors: Zhao Yong-Xing , Liu Dan-Xing , Liang Wen-Quan , Ye Zhi-Wei
Published: April 2012

Objectives

The aim of this study was to investigate the pharmacokinetics, tissue distribution and anti-tumour effect of hydroxycamptothecin submicron emulsions (HCPT-SEs).

Methods

HCPT-SEs or HCPT injection (HCPT-I) was administered intravenously into the tail vein of rats or S180 tumour-bearing mice.

Key findings

HCPT-SEs increased the plasma concentration of HCPT compared with HCPT-I at all time points. The AUC0-∞, elimination half-life and mean residence time of anionic submicron emulsions containing HCPT (HCPT-ASEs) and cationic submicron emulsions containing HCPT (HCPT-CSEs) were significantly greater than those of HCPT-I (P < 0.01). Especially, a prolonged elimination half-life was found for HCPT-CSEs. HCPT-CSEs and HCPT-ASEs resulted in a 7.9-fold and 3.1-fold increase in AUC0-6h of tumour compared with HCPT-I, respectively. The targeting efficiency (Te) of HCPT-ASEs and HCPT-CSEs indicated their selectivity to tumour and the Te of HCPT-CSEs was significantly higher than that of HCPT-ASEs (P < 0.01). The anti-tumour effect studies showed that HCPT-SEs improved the therapeutic efficiency of HCPT compared with HCPT-I. The percentage of tumour growth suppression rate of mice treated with HCPT-CSEs (2.0 mg HCPT eq./kg) increased 2.1 fold compared with that of HCPT-I.

Conclusions

Submicron emulsions can alter the pharmacokinetic characteristics and tissue distribution of HCPT, and enhance tumour targeting and anti-tumour activity.
The impact of treatment transitions between dialysis and transplantation on illness cognitions and quality of life – A prospective study
Authors: Griva Konstadina , Davenport Andrew , Harrison Michael , Newman Stanton P.
Published: April 2012

Objectives. Treatment transitions are frequent in end‐stage renal disease (ESRD) but little is known about cognitive responses pre‐ to post‐transplantation or after transplant failure. The purpose of this study was to examine changes in illness cognitions across treatment transitions between dialysis and transplantation and their impact on quality of life (QOL).

Methods. In this longitudinal study, ESRD patients (N= 262) patients were followed up across treatment transitions over a 7‐year observation window using the Illness Perceptions Questionnaire, the Illness Effects Questionnaire, and measures of QOL. Study sample comprised the patients from this cohort who switched treatment modality (N= 60 post‐transplantation; N= 28 transplant failure). Data were collected while on dialysis or transplantation and at 6 months post‐treatment change.

Results. Significant changes in QOL and illness perceptions were found in treatment transitions with opposite patterns of either improvement or deterioration following transplantation or transplantation failure. Pre‐ to post‐transplantation, QOL improves and patients report less symptoms, lower consequences, and illness intrusiveness, more acute timeline and stronger control beliefs (ps < .01). QOL is diminished following transplant failure and patients report more symptoms, consequences, illness disruptiveness, more chronic timeline, and lower control. Changes in cognitions are associated with changes in QOL (R2= .469–.789).

Conclusions. Treatment transitions marked significant changes in illness perceptions that were associated with changes in QOL. Interventions to prepare patients for treatment transitions and prevent increasingly negative patterns of illness perceptions with transplant failure may serve towards maintaining or improving adjustment outcomes.

Statement of contribution

What is already known on this subject? 

Illness cognitions have been shown to predict health outcomes and to change in response to changes in health status. Treatment transitions between dialysis and transplantation are frequent in end stage renal disease but their effect on illness representations has not been explored.

What does this study add? 

The paper described results of the first study to prospectively explore changes in illness cognitions across treatment transitions between dialysis and transplantation and their impact on QOL outcomes. The paper documents dynamic changes in illness cognitions when treatment modality is changed in line with the predictions of a dynamic reassessment of illness perceptions and coping behaviour as described in Leventhal's Common Sense Model of Illness Behaviour.
Bubble Structures Between Two Walls in Ultrasonic Cavitation Erosion
Authors: Abouel-Kasem A. , Ahmed S. M.
Published: April 2012

The cavitation bubble structures for the stationary specimen method were clarified for various distances, h, between the stationary specimen and the horn-tip surface. The generated cavitation bubbles constituted a huge number of tiny bubbles and bubble clusters of different sizes. The maximum cluster size was 1.4 mm. The observed cavitation patterns systematically changed during tests from the subcavitating state to the supercavitating state with respect to the separation distance, h. For h <4 mm, the bubbles have a definite trajectory, and the pressure patterns manifest a circular shape as a result of streaming induced by ultrasonic cavitation. The feature morphology of the eroded surfaces revealed that the predominant failure mode was fatigue. In the light of the material failure features and the cavitation patterns, it is also deduced that the important mechanism to transfer the cavitation energy to the solid is shock pressures accompanied by collapsing clusters.
Micro-Magnetic Field Arrayed Surface for Ferrofluids Lubrication
Authors: Liao Sijie , Huang Wei , Wang Xiaolei
Published: April 2012

CoNiMnP permanent magnetic films have been electroplated into arrayed round dimples (with diameters from 100 μm to 700 μm) machined on the substrate surface (316 stainless steel). These films could be magnetized and could generate the arrayed micro-magnetic field. Compared with normal surfaces (316 stainless steel flat surfaces without any dimples or coatings), the frictional properties of such magnetic surfaces were investigated under different loads and sliding speeds when lubricated with ferrofluids using a friction test rig. Much attention was paid to the effect of the dimple sizes on the lubrication properties. In addition, the magnetic properties of the dimples arrayed surface were analyzed by finite element analysis software (Ansoft Maxwell 3D). The results show that there exists the optimized geometrical parameter of the arrayed magnetic surface, which displays the best tribological performance when lubricated with ferrofluids.
Normalized Ashurst-Hoover Scaling and a Comprehensive Viscosity Correlation for Compressed Liquids
Authors: Bair Scott , Laesecke Arno
Published: April 2012

The recent move toward physics-based elastohydrodynamics promises to yield advances in the understanding of the mechanisms of friction and film generation that were not possible a few years ago. However, the accurate correlation of the low-shear viscosity with temperature and pressure is an essential requirement. The Ashurst-Hoover thermodynamic scaling, which has been useful for thermal elastohydrodynamic simulation, is normalized here in a manner that maps the viscosity of three widely different liquids onto a master Stickel curve. The master curve can be represented by a combination of two exponential power law terms. These may be seen as expressions of different molecular interaction mechanisms similar to the two free-volume models of Batschinski-Hildebrand and Doolittle, respectively. The new correlation promises to yield more reasonable extrapolations to extreme conditions of temperature and pressure than free-volume models, and it removes the singularity that has prevented wide acceptance of free-volume models in numerical simulations.
Comparison of Two Control Methods for Minimally Invasive Surgical Instruments
Authors: Fan Chunman , Clogenson Hélène , Breedveld Paul , van den Dobbelsteen John J. , Dankelman Jenny
Published: April 2012

Laparoscopic surgery is performed with long and slender instruments through one or several incisions in the abdominal wall. Steerable instruments with flexible distal tips have been developed for improving the ease of access to anatomic structures. However, the development of an intuitive and efficient control method for such steerable instruments remains a challenge. To determine which interface are most intuitive and effective to control steerable instruments, the current study evaluates the performance of novices in orienting the tip of a steerable laparoscopic forceps using thumb control or wrist control. Using two steerable instruments, one controlled by the thumb and the other by the wrist, 24 novices were divided into two groups that had to carry out an experimental task in an EndoTrainer with one of the two instruments. The participants had to orient the tip of the instrument relative to five targets that were presented in a random order. After a break, the participants switched to a second measurement session with the other instrument, followed by a third measurement session with the first instrument. Each participant performed the task 240 times over the three measurement sessions. The performance was assessed by measuring the performance time, using a questionnaire and grading the work load. The performance time showed a significant learning curve for each control method. The shortest performance time was recorded during the third session with both control methods (42.7 s for thumb control and 44.6 s for wrist control). A significant difference in the performance time was observed in the second session (p <0.02) but not in the first and third session. The questionnaire showed that most participants had a preference for thumb control. After a brief training period, thumb control and wrist control did not reveal significant differences in task performance. However, thumb control was strongly preferred by the participants due to the perceptive feeling in performance.
Evaluation of hybrid depth scanning for carbon‐ion radiotherapy
Authors: Inaniwa Taku , Furukawa Takuji , Kanematsu Nobuyuki , Mori Shinichiro , Mizushima Kota , Sato Shinji , Toshito Toshiyuki , Shirai Toshiyuki , Noda Koji
Published: April 2012

Purpose:

In radiotherapy with a scanned carbon‐ion beam, its Bragg peak is shifted along the depth direction either by inserting the range shifter plates or by changing the beam‐extraction energy of a synchrotron. In the former technique (range shifter scanning: RS), the range shifter plates broaden the beam size and produce secondary fragments through nuclear reactions. In the latter technique (active‐energy scanning: ES), it may take several seconds to change the beam energy depending on the synchrotron operation cycle, leading to a long treatment time. The authors propose a hybrid depth scan technique (hybrid scanning: HS), where several beam energies are used in conjunction with the range shifter plates for finer range shift. In this study, HS is evaluated from the viewpoints of dose distribution and treatment time.

Methods:

Assuming realistic accelerator and beam‐delivery systems, the authors performed computer simulations usingGEANT4 Monte Carlo code for beam modeling and a treatment planning system to evaluate HS. Three target volumes with the same dimensions of 60 × 60 × 60 mm3 were generated at depths of 45, 85, and 125 mm in water phantom, and uniform clinical dose was planned for these targets. The sizes of lateral dose falloff and the peak to plateau ratio defined as the ratio of the clinical dose averaged over the target to the clinical dose at the entrance as well as the treatment time were compared among the three depth scan techniques.

Results:

The sizes of lateral dose falloffs at the center of SOBP are 11.4, 8.5, and 5.9 mm for the three targets in RS, while they are 5.7, 4.8, and 4.6 mm in ES and 6.6, 5.7, and 5.0 mm in HS, respectively. The peak to plateau ratios are 1.39, 1.96, and 2.15 in RS, while they are 1.48, 2.04, and 2.19 in ES and 1.47, 2.03, and 2.18 in HS, respectively. The treatment times are 128.7, 128.6, and 128.6 s in ES, while they are 61.2, 54.6, and 47.8 s in RS and 43.2, 44.1, and 44.7 s in HS, respectively. The multiple scattering and the nuclear reaction by range shifter degraded the beam qualities such as lateral dose falloff and peak to plateau ratio, which was especially pronounced for the shallow target in RS. The depth scan timing was limited by accelerator cycle in ES. That increased the treatment time by a few times.

Conclusions:

This study revealed that HS can provide dose distributions with steeper lateral dose falloffs and higher peak to plateau ratio comparing to RS and comparable to ES. In addition, the treatment time can be considerably reduced in HS compared to ES.
Comment on “Universality in the Evolution of Orientation Columns in the Visual Cortex”
Authors: Meng Yicong , Tanaka Shigeru , Poon Chi-Sang
Published: April 2012

Kaschube
et al
. (Reports, 19 November 2010, p. 1113) argue that pinwheel density in three mammalian species follows a universal constant of π as predicted by their orientation-selective suppressive long-range connectivity model. We dispute their conclusions and suggest that a simple brain size–pinwheel density scaling law suffices in predicting the self-organized and disorganized orientation maps from primates to rodents.
Engaging Undergraduates in Global Health Technology Innovation
Authors: Richards-Kortum Rebecca , Gray Lauren Vestewig , Oden Maria
Published: April 2012

“Appropriate Design for Global Health,” the IBI Prize–winning module, primes students to respond to global health challenges with novel technological solutions.
Multiblock Polymers: Panacea or Pandora’s Box?
Authors: Bates Frank S. , Hillmyer Marc A. , Lodge Timothy P. , Bates Christopher M. , Delaney Kris T. , Fredrickson Glenn H.
Published: April 2012

Getting Around the Block

Diblock copolymers provide a rich variety of morphologies that depend on the length of the polymer blocks, the overall fraction of each block, and their chemical dissimilarity. New synthetic methods have made it possible to make copolymers with three or more components and in a range of chemical architectures. However, this growth in design choices can offer too many variables to work with, and rational design is important, especially when trying to transform small-scale products in engineered commodities.

Bates
et al.

(p. 434) review the opportunities and complexities that exist when working in this expanded playground of block copolymers.
An Early-Branching Microbialite Cyanobacterium Forms Intracellular Carbonates
Authors: Couradeau Estelle , Benzerara Karim , Gérard Emmanuelle , Moreira David , Bernard Sylvain , Brown Gordon E. , López-García Purificación
Published: April 2012

Keep It Inside

Some cyanobacteria form solid-phase calcium carbonate precipitates as a consequence of fixing CO
2
during photosynthesis. Usually, such carbonates form extracellularly near the surface of the cells, sometimes generating structures called stromatolites. In a biofilm growing on carbonate deposits in Lake Alchichica, Mexico,

Couradeau
et al.

(p. 459; see the Perspective by

Riding

) discovered one species of cyanobacteria that also precipitates amorphous carbonate particles internally. Because the structure and chemical composition of these carbonates is distinct from those formed extracellularly, there may be cellular control over the mineralization process. These precipitates may influence physiological processes such as cell buoyancy and the sequestration of excess alkalinity generated during photosynthesis.
Origins and Genetic Legacy of Neolithic Farmers and Hunter-Gatherers in Europe
Authors: Skoglund Pontus , Malmström Helena , Raghavan Maanasa , Storå Jan , Hall Per , Willerslev Eske , Gilbert M. Thomas P. , Götherström Anders , Jakobsson Mattias
Published: April 2012

Farmer Displaced European Hunters

Our understanding of prehistoric demography and human evolution has been improved by analysis of ancient DNA.

Skoglund
et al.

(p. 466) describe the retrieval and analysis of genomic DNA from ancient (~5000-year-old) northern European Neolithic individuals within modern Sweden. These include three hunter-gatherers from the Pitted Ware Culture horizon and one farmer ascribed to the Mid-Neolithic North-Central TRB culture. The hunter-gatherers displayed a distinct genetic signature, similar to that of extant northern Europeans, whereas the farmer's genetic signature more closely resembled southern Europeans, suggesting migration and admixture during the spread of farming.
Function and Molecular Mechanism of Acetylation in Autophagy Regulation
Authors: Yi Cong , Ma Meisheng , Ran Leili , Zheng Jingxiang , Tong Jingjing , Zhu Jing , Ma Chengying , Sun Yufen , Zhang Shaojin , Feng Wenzhi , Zhu Liyuan , Le Yan , Gong Xingqi , Yan Xianghua , Hong Bing , Jiang Fen-Jun , Xie Zhiping , Miao Di , Deng Haiteng , Yu Li
Published: April 2012

Acetylation and Autophagy

Autophagy allows cells to digest their own components when necessary to survive stressful conditions.

Lin
et al.

(p. 477) and

Yi
et al.

(p. 474) describe signaling mechanisms in mammalian cells and yeast, respectively, by which autophagy is regulated by protein acetylation. In mammalian cells deprived of serum, the acetyltransferase TIP60 was activated by phosphorylation by the protein kinase GSK3 (glycogen synthase kinase 3). TIP60's target appeared to be a protein kinase central to autophagy regulation, ULK1. This activating pathway was required for autophagy in the absence of serum, but was not needed for autophagy in cells deprived of glucose. In the yeast
Saccharomyces cerevisiae
starved of nitrogen, another acetylation mechanism was uncovered. Starvation led to activation of the histone acetyltransferase Esa1, which acetylated the protein Atg3, a key component of the autophagy machinery, thus increasing its interaction with another autophagy protein, Atg8.
GSK3-TIP60-ULK1 Signaling Pathway Links Growth Factor Deprivation to Autophagy
Authors: Lin Shu-Yong , Li Terytty Yang , Liu Qing , Zhang Cixiong , Li Xiaotong , Chen Yan , Zhang Shi-Meng , Lian Guili , Liu Qi , Ruan Ka , Wang Zhen , Zhang Chen-Song , Chien Kun-Yi , Wu Jiawei , Li Qinxi , Han Jiahuai , Lin Sheng-Cai
Published: April 2012

Acetylation and Autophagy

Autophagy allows cells to digest their own components when necessary to survive stressful conditions.

Lin
et al.

(p. 477) and

Yi
et al.

(p. 474) describe signaling mechanisms in mammalian cells and yeast, respectively, by which autophagy is regulated by protein acetylation. In mammalian cells deprived of serum, the acetyltransferase TIP60 was activated by phosphorylation by the protein kinase GSK3 (glycogen synthase kinase 3). TIP60's target appeared to be a protein kinase central to autophagy regulation, ULK1. This activating pathway was required for autophagy in the absence of serum, but was not needed for autophagy in cells deprived of glucose. In the yeast
Saccharomyces cerevisiae
starved of nitrogen, another acetylation mechanism was uncovered. Starvation led to activation of the histone acetyltransferase Esa1, which acetylated the protein Atg3, a key component of the autophagy machinery, thus increasing its interaction with another autophagy protein, Atg8.
In Situ Evolutionary Rate Measurements Show Ecological Success of Recently Emerged Bacterial Hybrids
Authors: Denef Vincent J. , Banfield Jillian F.
Published: April 2012

Acid Rate

The low species richness of the acid mine drainage in the Richmond Mine (Iron Mountain, California, USA) provides an excellent opportunity to study microbial process on a genome scale in real time.
Denef and Banfield
(p. 462; see the Perspective by

DeLong

) report the further analysis of metagenomic data from 24 microbial biofilm samples collected over 8 years, at different sites. High-throughput, shotgun sequencing of the DNA was used to look for high-frequency, single-nucleotide polymorphisms in six genotypic variants of a chemolithoautotroph,
Leptospirillum
group II, the dominant primary producer and iron-oxidizer. Thirteen samples collected at one site over 5 years were analyzed to infer the accumulation of single-nucleotide substitutions for free-living populations over time. A series of very recent branching points in the phylogenetic tree that arose via homologous recombination were revealed.
A 920-Kilometer Optical Fiber Link for Frequency Metrology at the 19th Decimal Place
Authors: Predehl K. , Grosche G. , Raupach S. M. F. , Droste S. , Terra O. , Alnis J. , Legero Th. , Hänsch T. W. , Udem Th. , Holzwarth R. , Schnatz H.
Published: April 2012

Synchronize Watches

Time standards based on the energy-level transitions of atoms and ions provide the most accurate and precise methods of time keeping. Measurements made in one laboratory and in another must be done with clocks that have been synchronized and calibrated to ensure that the same measurement is being made. Such clocks, however, are not particularly mobile and are housed in national metrology labs.

Predehl
et al.

(p. 441; see the Perspective by

Warrington

) linked two optical clocks separated by over 900 kilometers using optical fiber to show that the clocks can be synchronized, with the clocks showing a frequency stability better than 3.7 × 10
−19
. Such long-distance synchronization should allow for tests of fundamental physics, such as general relativity and quantum electrodynamics.
Revealing the Angular Symmetry of Chemical Bonds by Atomic Force Microscopy
Authors: Welker Joachim , Giessibl Franz J.
Published: April 2012

Working the Angles on Chemical Bonding

The forces exerted by chemical bonds depend not only on the distances between atoms but also upon the angles between them.
Welker and Giessibl
(p. 444; see the cover) probed the angular dependence of the CO molecule adsorbed on top of a copper atom on an atomically flat Cu(111) surface using both atomic force microscopy and scanning tunneling microscopy (STM). Probe tips with three different tip-atom-symmetry environments were used. All three tips delivered similar STM images, but force probes revealed the angular dependence of the CO bond to the surface and provided data for a model of the changes in bond energy.
Two Atomic Clocks Ticking as One
Authors: Warrington Bruce
Published: April 2012

Optical fiber networks allow synchronization of distant optical clocks, which tick too fast to be linked via satellite signals.
A Hard Life for Cyanobacteria
Authors: Riding Robert
Published: April 2012

The discovery of calcification inside present-day cyanobacteria raises questions about their geologic record.
Despite Gains, Malnutrition Among China's Rural Poor Sparks Concern
Authors: Stone Richard
Published: April 2012

The Chinese Center for Disease Control and Prevention is seeking to improve nutrition for infants and young children and this year plans to double the 100-strong scientific staff of its Institute of Nutrition and Health.
Textbook Electrodynamics May Contradict Relativity
Authors: Cho Adrian
Published: April 2012

A scientist claims that the classic formula for the force exerted by electric and magnetic fields—the so-called Lorentz force—clashes with Einstein's special theory of relativity.
The Greenhouse Is Making the Water-Poor Even Poorer
Authors: Kerr Richard A.
Published: April 2012

A new study of the ocean's changing salinity in this week's issue of
Science
confirms that a strengthening greenhouse will increase precipitation where it is already relatively high and decrease it where it is already low.
Mutagenesis of the DI/DIII Linker in Dengue Virus Envelope Protein Impairs Viral Particle Assembly
Authors: de Wispelaere Melissanne , Yang Priscilla L.
Published: April 2012

The dengue virus (DV) envelope (E) protein is important in mediating viral entry and assembly of progeny virus during cellular infection. Domains I and III (DI and DIII, respectively) of the DV E protein are connected by a highly conserved but poorly ordered region, the DI/DIII linker. Although the flexibility of the DI/DIII linker is thought to be important for accommodating the structural rearrangements undergone by the E protein during viral entry, the function of the linker in the DV infectious cycle is not well understood. In this study, we performed site-directed mutagenesis on conserved residues in the DI/DIII linker of the DV2 E protein and showed that the resulting mutations had little or no effect on the entry process but greatly affected virus assembly. Biochemical fractionation and immunofluorescence microscopy experiments performed on infectious virus as well as in a virus-like particle (VLP) system indicate that the DI/DIII linker mutants express the DV structural proteins at the sites of particle assembly near the ER but fail to form infectious particles. This defect is not due to disruption of E's interaction with prM and pr in immature and mature virions, respectively. Serial passaging of the DV2 mutant E-Y299F led to the identification of a mutation in the membrane-proximal stem region of E that fully compensates for the assembly defect of this DI/DIII linker mutant. Together, our results suggest a critical and previously unidentified role for the E protein DI/DIII linker region during the DV2 assembly process.
Mutations Conferring Resistance to Viral DNA Polymerase Inhibitors in Camelpox Virus Give Different Drug-Susceptibility Profiles in Vaccinia Virus
Authors: Duraffour Sophie , Andrei Graciela , Topalis Dimitri , Krečmerová Marcela , Crance Jean-Marc , Garin Daniel , Snoeck Robert
Published: April 2012

Cidofovir or (S)-HPMPC is one of the three antiviral drugs that might be used for the treatment of orthopoxvirus infections. (S)-HPMPC and its 2,6-diaminopurine counterpart, (S)-HPMPDAP, have been described to select,in vitro, for drug resistance mutations in the viral DNA polymerase (E9L) gene of vaccinia virus (VACV). Here, to extend our knowledge of drug resistance development among orthopoxviruses, we selected,in vitro, camelpox viruses (CMLV) resistant to (S)-HPMPDAP and identified a single amino acid change, T831I, and a double mutation, A314V+A684V, within E9L. The production of recombinant CMLV and VACV carrying these amino acid substitutions (T831I, A314V, or A314V+A684V) demonstrated clearly their involvement in conferring reduced sensitivity to viral DNA polymerase inhibitors, including (S)-HPMPDAP. Both CMLV and VACV harboring the A314V change showed comparable drug-susceptibility profiles to various antivirals and similar impairments in viral growth. In contrast, the single change T831I and the double change A314V+A684V in VACV were responsible for increased levels of drug resistance and for cross-resistance to viral DNA polymerase antivirals that were not observed with their CMLV counterparts. Each amino acid change accounted for an attenuated phenotype of VACVin vivo. Modeling of E9L suggested that the T→I change at position 831 might abolish hydrogen bonds between E9L and the DNA backbone and have a direct impact on the incorporation of the acyclic nucleoside phosphonates. Our findings demonstrate that drug-resistance development in two related orthopoxvirus species may impact drug-susceptibility profiles and viral fitness differently.
Antiviral Antibodies and T Cells Are Present in the Foreskin of Simian Immunodeficiency Virus-Infected Rhesus Macaques
Authors: Rothaeusler Kristina , Ma Zhong-Min , Qureshi Huma , Carroll Timothy D. , Rourke Tracy , McChesney Michael B. , Miller Christopher J.
Published: April 2012

No information exists regarding immune responses to human immunodeficiency virus (HIV) infection in the foreskin or glans of the human penis, although this is a key tissue for HIV transmission. To address this gap, we characterized antiviral immune responses in foreskin of male rhesus macaques (RMs) inoculated with simian immunodeficiency virus (SIV) strain SIVmac251 by penile foreskin exposure. We found a complete population of immune cells in the foreskin and glans of normal RMs, although B cells were less common than CD4+and CD8+T cells. IgG-secreting cells were detected by enzyme-linked immunospot (ELISPOT) assay in cell suspensions made from the foreskin. In the foreskin and glans of SIV-infected RMs, although B cells were less common than CD4+and CD8+T cells, SIV-specific IgG antibody was present in foreskin secretions. In addition, cytokine-secreting SIV-specific CD8+T cells were readily found in cell suspensions made from the foreskin. Although potential HIV target cells were found in and under the epithelium covering all penile surfaces, the presence of antiviral effector B and T cells in the foreskin suggests that vaccines may be able to elicit immunity in this critical site to protect men from acquiring HIV.
Base Pairing between Hepatitis C Virus RNA and MicroRNA 122 3′ of Its Seed Sequence Is Essential for Genome Stabilization and Production of Infectious Virus
Authors: Shimakami Tetsuro , Yamane Daisuke , Welsch Christoph , Hensley Lucinda , Jangra Rohit K. , Lemon Stanley M.
Published: April 2012

MicroRNA 122 (miR-122) facilitates hepatitis C virus (HCV) replication by recruiting an RNA-induced silencing complex (RISC)-like complex containing argonaute 2 (Ago2) to the 5′ end of the HCV genome, thereby stabilizing the viral RNA. This requires base pairing between the miR-122 “seed sequence” (nucleotides [nt] 2 to 8) and two sequences near the 5′ end of the HCV RNA: S1 (nt 22 to 28) and S2 (nt 38 to 43). However, recent reports suggest that additional base pair interactions occur between HCV RNA and miR-122. We searched 606 sequences from a public database (genotypes 1 to 6) and identified two conserved, putatively single-stranded RNA segments, upstream of S1 (nt 2 and 3) and S2 (nt 30 to 34), with potential for base pairing to miR-122 (nt 15 and 16 and nt 13 to 16, respectively). Mutagenesis and genetic complementation experiments confirmed that HCV nt 2 and 3 pair with nt 15 and 16 of miR-122 bound to S1, while HCV nt 30 to 33 pair with nt 13 to 16 of miR-122 at S2. In genotype 1 and 6 HCV, nt 4 also base pairs with nt 14 of miR-122. These 3′ supplementary base pair interactions of miR-122 are functionally important and are required for Ago2 recruitment to HCV RNA by miR-122, miR-122-mediated stabilization of HCV RNA, and production of infectious virus. However, while complementary mutations at HCV nt 30 and 31 efficiently rescued the activity of a 15C,16C miR-122 mutant targeting S2, similar mutations at nt 2 and 3 failed to rescue Ago2 recruitment at S1. These data add to the current understanding of miR-122 interactions with HCV RNA but indicate that base pairing between miR-122 and the 5′ 43 nt of the HCV genome is more complex than suggested by existing models.
The Influenza A Virus PB2, PA, NP, and M Segments Play a Pivotal Role during Genome Packaging
Authors: Gao Qinshan , Chou Yi-Ying , Doğanay Sultan , Vafabakhsh Reza , Ha Taekjip , Palese Peter
Published: April 2012

The genomes of influenza A viruses consist of eight negative-strand RNA segments. Recent studies suggest that influenza viruses are able to specifically package their segmented genomes into the progeny virions. Segment-specific packaging signals of influenza virus RNAs (vRNAs) are located in the 5′ and 3′ noncoding regions, as well as in the terminal regions, of the open reading frames. How these packaging signals function during genome packaging remains unclear. Previously, we generated a 7-segmented virus in which the hemagglutinin (HA) and neuraminidase (NA) segments of the influenza A/Puerto Rico/8/34 virus were replaced by a chimeric influenza C virus hemagglutinin/esterase/fusion (HEF) segment carrying the HA packaging sequences. The robust growth of the HEF virus suggested that the NA segment is not required for the packaging of other segments. In this study, in order to determine the roles of the other seven segments during influenza A virus genome assembly, we continued to use this HEF virus as a tool and analyzed the effects of replacing the packaging sequences of other segments with those of the NA segment. Our results showed that deleting the packaging signals of the PB1, HA, or NS segment had no effect on the growth of the HEF virus, while growth was greatly impaired when the packaging sequence of the PB2, PA, nucleoprotein (NP), or matrix (M) segment was removed. These results indicate that the PB2, PA, NP, and M segments play a more important role than the remaining four vRNAs during the genome-packaging process.
Comparison of the Host Immune Response to Herpes Simplex Virus 1 (HSV-1) and HSV-2 at Two Different Mucosal Sites
Authors: Zheng Min , Conrady Christopher D. , Ward Julie M. , Bryant-Hudson Katie M. , Carr Daniel J. J.
Published: April 2012

A study was undertaken to compare the host immune responses to herpes simplex virus 1 (HSV-1) and HSV-2 infection by the ocular or genital route in mice. Titers of HSV-2 from tissue samples were elevated regardless of the route of infection. The elevation in titers of HSV-2, including cell infiltration and cytokine/chemokine levels in the central nervous system relative to those found following HSV-1 infection, was correlative with inflammation. These results underscore a dichotomy between the host immune responses to closely related alphaherpesviruses.
Loss of Cytoskeletal Transport during Egress Critically Attenuates Ectromelia Virus Infection
In Vivo
Authors: Lynn Helena , Horsington Jacquelyn , Ter Lee Kuan , Han Shuyi , Chew Yee Lian , Diefenbach Russell J. , Way Michael , Chaudhri Geeta , Karupiah Gunasegaran , Newsome Timothy P.
Published: April 2012

Egress of wrapped virus (WV) to the cell periphery following vaccinia virus (VACV) replication is dependent on interactions with the microtubule motor complex kinesin-1 and is mediated by the viral envelope protein A36. Here we report that ectromelia virus (ECTV), a related orthopoxvirus and the causative agent of mousepox, encodes an A36 homologue (ECTV-Mos-142) that is highly conserved despite a large truncation at the C terminus. Deleting the ECTV A36R gene leads to a reduction in the number of extracellular viruses formed and to a reduced plaque size, consistent with a role in microtubule transport. We also observed a complete loss of virus-associated actin comets, another phenotype dependent on A36 expression during VACV infection. ECTV ΔA36R was severely attenuated when used to infect the normally susceptible BALB/c mouse strain. ECTV ΔA36R replication and spread from the draining lymph nodes to the liver and spleen were significantly reduced in BALB/c mice and in Rag-1-deficient mice, which lack T and B lymphocytes. The dramatic reduction in ECTV ΔA36R titers early during the course of infection was not associated with an augmented immune response. Taken together, these findings demonstrate the critical role that subcellular transport pathways play not only in orthopoxvirus infection in an
in vitro
context but also during orthopoxvirus pathogenesis in a natural host. Furthermore, despite the attenuation of the mutant virus, we found that infection nonetheless induced protective immunity in mice, suggesting that orthopoxvirus vectors with A36 deletions may be considered another safe vaccine alternative.
Isoflavone Agonists of IRF-3 Dependent Signaling Have Antiviral Activity against RNA Viruses
Authors: Bedard Kristin M. , Wang Myra L. , Proll Sean C. , Loo Yueh-Ming , Katze Michael G. , Gale Michael , Iadonato Shawn P.
Published: April 2012

There is a growing need for novel antiviral therapies that are broad spectrum, effective, and not subject to resistance due to viral mutations. Using high-throughput screening methods, including computational docking studies and an interferon-stimulated gene 54 (ISG54)-luciferase reporter assay, we identified a class of isoflavone compounds that act as specific agonists of innate immune signaling pathways and cause activation of the interferon regulatory factor (IRF-3) transcription factor. The isoflavone compounds activated the ISG54 promoter, mediated nuclear translocation of IRF-3, and displayed highly potent activity against hepatitis C virus (HCV) and influenza virus. Additionally, these agonists efficiently activated IRF-3 in the presence of the HCV protease NS3-4A, which is known to blunt the host immune response. Furthermore, genomic studies showed that discrete innate immune pathways centered on IRF signaling were regulated following agonist treatment without causing global changes in host gene expression. Following treatment, the expression of only 64 cellular genes was significantly induced. This report provides the first evidence that innate immune pathways dependent on IRF-3 can be successfully targeted by small-molecule drugs for the development of novel broad-spectrum antiviral compounds.
Dynamic Interactions between Bombyx mori Nucleopolyhedrovirus and Its Host Cells Revealed by Transcriptome Analysis
Authors: Xue Jian , Qiao Nan , Zhang Wei , Cheng Ruo-Lin , Zhang Xiao-Qin , Bao Yan-Yuan , Xu Yi-Peng , Gu Lin-Zhu , Han Jing-Dong Jackie , Zhang Chuan-Xi
Published: April 2012

Although microarray and expressed sequence tag (EST)-based approaches have been used to profile gene expression during baculovirus infection, the response of host genes to baculovirus infection and the interaction between baculovirus and its host remain largely unknown. To determine the host response to
Bombyx mori
nucleopolyhedrovirus infection and the dynamic interaction between the virus and its host, eight digital gene expression libraries were examined in a Bm5 cell line before infection and at 1.5, 3, 6, 12, 24, 48, and 96 h postinfection. Gene set enrichment analysis of differentially expressed genes at each time point following infection showed that gene sets including cytoskeleton, transcription, translation, energy metabolism, iron ion metabolism, and the ubiquitin-proteasome pathway were altered after viral infection. In addition, a time course depicting protein-protein interaction networks between the baculovirus and the host were constructed and revealed that viral proteins interact with a multitude of cellular machineries, such as the proteasome, cytoskeleton, and spliceosome. Several viral proteins, including IE2, CG30, PE38, and PK-1/2, were predicted to play key roles in mediating virus-host interactions. Based on these results, we tested the role of the ubiquitin-proteasome pathway and iron ion metabolism in the viral infection cycle. Treatment with a proteasome inhibitor and deferoxamine mesylate
in vitro
and
in vivo
confirmed that these pathways regulate viral infection. Taken together, these findings provide new insights into the interaction between the baculovirus and its host and identify molecular mechanisms that can be used to block viral infection and improve baculovirus expression systems.
Hepatitis C Virus Attachment Mediated by Apolipoprotein E Binding to Cell Surface Heparan Sulfate
Authors: Jiang Jieyun , Cun Wei , Wu Xianfang , Shi Qing , Tang Hengli , Luo Guangxiang
Published: April 2012

Viruses are known to use virally encoded envelope proteins for cell attachment, which is the very first step of virus infection. In the present study, we have obtained substantial evidence demonstrating that hepatitis C virus (HCV) uses the cellular protein apolipoprotein E (apoE) for its attachment to cells. An apoE-specific monoclonal antibody was able to efficiently block HCV attachment to the hepatoma cell line Huh-7.5 as well as primary human hepatocytes. After HCV bound to cells, however, anti-apoE antibody was unable to inhibit virus infection. Conversely, the HCV E2-specific monoclonal antibody CBH5 did not affect HCV attachment but potently inhibited HCV entry. Similarly, small interfering RNA-mediated knockdown of the key HCV receptor/coreceptor molecules CD81, claudin-1, low-density lipoprotein receptor (LDLr), occludin, and SR-BI did not affect HCV attachment but efficiently suppressed HCV infection, suggesting their important roles in HCV infection at postattachment steps. Strikingly, removal of heparan sulfate from the cell surface by treatment with heparinase blocked HCV attachment. Likewise, substitutions of the positively charged amino acids with neutral or negatively charged residues in the receptor-binding region of apoE resulted in a reduction of apoE-mediating HCV infection. More importantly, mutations of the arginine and lysine to alanine or glutamic acid in the receptor-binding region ablated the heparin-binding activity of apoE, as determined by an
in vitro
heparin pulldown assay. HCV attachment could also be inhibited by a synthetic peptide derived from the apoE receptor-binding region. Collectively, these findings demonstrate that apoE mediates HCV attachment through specific interactions with cell surface heparan sulfate.
Spinal Nerve Root Electroacupuncture for Symptomatic Treatment of Lumbar Spinal Canal Stenosis Unresponsive to Standard Acupuncture: A Prospective Case Series
Authors: Inoue Motohiro , Nakajima Miwa , Hojo Tatsuya , Kitakoji Hiroshi , Itoi Megumi
Published: April 2012

Objective

To study the effectiveness of electroacupuncture of the spinal nerve root using a selective spinal nerve block technique for the treatment of lumbar and lower limb symptoms in patients with lumbar spinal canal stenosis.

Methods

Subjects were 17 patients with spinal canal stenosis who did not respond to 2 months of general conservative treatment and conventional acupuncture. Under x-ray fluoroscopy, two acupuncture needles were inserted as close as possible to the relevant nerve root, as determined by subjective symptoms and x-ray and MRI findings, and low-frequency electroacupuncture stimulation was performed (10 Hz, 10 min). Patients received 3–5 once-weekly treatments, and were evaluated immediately before and after each treatment and 3 months after completion of treatment.

Results

After the first nerve root electroacupuncture stimulation, scores for lumbar and lower limb symptoms improved significantly (low back pain, p<0.05; lower limb pain, p<0.05; lower limb dysaesthesia, p<0.01) with some improvement in continuous walking distance. Symptom scores and continuous walking distance showed further improvement before the final treatment (p<0.01), and a significant sustained improvement was observed 3 months after completion of treatment (p<0.01).

Conclusion

Lumbar and lower limb symptoms, for which conventional acupuncture and general conservative treatment had been ineffective, improved significantly during a course of electroacupuncture to the spinal nerve root, showing sustained improvement even 3 months after completion of treatment. The mechanisms of these effects may involve activation of the pain inhibition system and improvement of nerve blood flow.