bluuebunny/crossref_metadata_2025 huggingface dataset:
Antibiotic selection leads to inadvertent selection of nfxC‐type phenotypic mutants in Pseudomonas aeruginosa
Authors: Mooij Marlies J. , O'Connor Hazel F. , Tian Zhe‐Xian , Wang Yi‐Ping , Adams Claire , Morrissey John P. , O'Gara Fergal
Published: May 2010

Spontaneous nfxC‐type phenotypic mutants of Pseudomonas aeruginosa are characterized by chloramphenicol resistance and increased expression of the multidrug efflux pump, MexEF‐OprN. These mutants frequently arise during the propagation of bacteria in laboratory conditions. This study shows that some of the discrepancies in transcriptomic/phenotypic profiles of two rsmA mutants, PAZH13 (rsmA mutant in strain PAO1) and PAKΔrsmA, are due to the nfxC‐type nature of PAZH13. This indicates that awareness of the possible occurrence of these spontaneous nfxC‐type phenotypes is necessary. Screening of mexE levels could provide clarity when an nfxC‐type phenotype is suspected.
THE NECESSITY OF TOMORROW'S SEA BATTLE
Authors: Byrd Jeremy
Published: May 2010

abstract

In chapter 9 of De Interpretatione, Aristotle offers a defense of free will against the threat of fatalism. According to the traditional interpretation, Aristotle concedes the validity of the fatalist's arguments and then proceeds to reject the Principle of Bivalence in order to avoid the fatalist's conclusion. Assuming that the traditional interpretation is right on this point, it remains to be seen why Aristotle felt compelled to reject such an intuitive semantic principle rather than challenge the fatalist's inference from truth to necessity. The answer, I contend, lies in Aristotle's theory of truth and truthmakers.
“STANDING APART IN THE SHELTER OF THE CITY WALL”: THE CONTEMPLATIVE IDEAL VS. THE POLITICALLY ENGAGED PHILOSOPHER IN PLATO'S POLITICAL THEORY
Authors: McKeen Catherine
Published: May 2010

abstract

Natural philosophers seem to have good reasons to prefer that the kallipolis, the maximally just community of the Republic, is never realized. If such a community is realized, philosophers are under the obligation of a just demand that they govern. However, a life that contains governance as a significant part is not the happiest life a philosopher can live. The happiest life for a philosopher is one consisting entirely or largely in philosophical contemplation. I confront this puzzle by arguing that natural philosophers gain benefits in the kallipolis that are not available to them in other communities, primarily opportunities for correction and punishment. While other communities may offer philosophers more opportunities for philosophical contemplation, these communities do not provide a reliable mechanism for counteracting potentially dangerous moral blindness. In contrast to other communities, the kallipolis institutionalizes and reliably replicates the structures necessary for counteracting moral blindness.
Vertical and lateral drift corrections of scanning probe microscopy images
Authors: Rahe P. , Bechstein R. , Kühnle A.
Published: May 2010

A procedure is presented for image correction of scanning probe microscopy data that is distorted by linear thermal drift. The procedure is based on common ideas for drift correction, which the authors combine to a comprehensive step-by-step description of how to measure drift velocities in all three dimensions and how to correct the images using these velocities. The presented method does not require any knowledge about size or shape of the imaged structures. Thus, it is applicable to any type of scanning probe microscopy image, including images lacking periodic structures. Besides providing a simple, ready-to-use description of lateral and vertical drift correction, they derive all formulas needed from the model of linear drift.
Very compact design for a low-temperature tuning fork atomic force microscope
Authors: Wintjes N. , Lange M. , van Vörden D. , Karacuban H. , Utzat D. , Möller R.
Published: May 2010

The authors present a new design for a tuning fork based noncontact atomic force microscope. The very compact construction in the form of a cylinder with a diameter of only 3 cm and a height of 10 cm makes the microscope especially suitable for measurements at low temperatures. Thermal drift rates are found to be about 1 Å/h at 7 K. Furthermore, the design allows for in situ exchange of the tuning fork even at low temperatures. The performance of the microscope is demonstrated by topographic and spectroscopic measurements on a Ag(111) surface at room temperature and at a temperature of 7 K.
Application of the KolibriSensor® to combined atomic-resolution scanning tunneling microscopy and noncontact atomic-force microscopy imaging
Authors: Torbrügge Stefan , Schaff Oliver , Rychen Jörg
Published: May 2010

Combined atomic-resolution scanning tunneling microscopy (STM) and noncontact atomic-force microscopy (NC-AFM) studies are carried out with the piezoelectric KolibriSensor in ultrahigh vacuum at room temperature. The sensor exhibits a very low spectral deflection noise density of only 6.5 fm/Hz which favors in combination with its high spring constant of 540 000 N/m stable NC-AFM operation at subnanometer oscillation amplitudes. The authors present atomic-resolution imaging on the Si(111)(7×7) surface recorded in STM and NC-AFM feedback mode. They find that the tip surface distance during atomic-resolution imaging on silicon is much smaller for NC-AFM compared to STM. It is shown that atomic-resolution NC-AFM and dynamic STM images of the same area on the Si(111)(7×7) surface enable a discrimination of vacancies and adsorbates. Furthermore, the topography of graphite imaged in dynamic STM and NC-AFM feedback mode is compared.
A Global Protein Kinase and Phosphatase Interaction Network in Yeast
Authors: Breitkreutz Ashton , Choi Hyungwon , Sharom Jeffrey R. , Boucher Lorrie , Neduva Victor , Larsen Brett , Lin Zhen-Yuan , Breitkreutz Bobby-Joe , Stark Chris , Liu Guomin , Ahn Jessica , Dewar-Darch Danielle , Reguly Teresa , Tang Xiaojing , Almeida Ricardo , Qin Zhaohui Steve , Pawson Tony , Gingras Anne-Claude , Nesvizhskii Alexey I. , Tyers Mike
Published: May 2010

Budding Yeast Kinome Revealed

Covalent modification of proteins by phosphorylation is a primary means by which cells control the biochemical activities and functions of proteins. To better understand the full spectrum of cellular control mechanisms mediated by phosphorylation,

Breitkreutz
et al.

(p.
1043
; see the Perspective by

Levy
et al.

) used mass spectrometry to identify proteins that interacted with the complete set of protein kinases from budding yeast and with other molecules, including phosphatases, which influence phosphorylation reactions. The results reveal a network of interacting protein kinases and phosphatases, and analysis of other interacting proteins suggests previously undiscovered roles for many of these enzymes.
Primordial Gravitational Waves and Cosmology
Authors: Krauss Lawrence M. , Dodelson Scott , Meyer Stephan
Published: May 2010

Astronomical Inflation

In astronomy, according to the theory of inflation, the universe underwent a period of extremely accelerated expansion when it was only a fraction of a second old. This process made the universe flat, isotropic, and homogeneous, and it explains how quantum mechanical seeds developed into the large-scale structure we observe today. The theory also predicts that gravitational waves were produced during the early inflationary phase. Alternative theories either predict no gravitational waves or waves with different properties.

Krauss
et al.

(p.
989
) review how primordial gravitational waves could provide information on the physics shortly after the Big Bang and how they could be detected indirectly through their imprint on the cosmic microwave background radiation—relic radiation from the Big Bang released when the universe became transparent to electromagnetic radiation.
Self-Assembly of Janus Dendrimers into Uniform Dendrimersomes and Other Complex Architectures
Authors: Percec Virgil , Wilson Daniela A. , Leowanawat Pawaret , Wilson Christopher J. , Hughes Andrew D. , Kaucher Mark S. , Hammer Daniel A. , Levine Dalia H. , Kim Anthony J. , Bates Frank S. , Davis Kevin P. , Lodge Timothy P. , Klein Michael L. , DeVane Russell H. , Aqad Emad , Rosen Brad M. , Argintaru Andreea O. , Sienkowska Monika J. , Rissanen Kari , Nummelin Sami , Ropponen Jarmo
Published: May 2010

Janus Drug Delivery Vehicle

Efficient drug delivery vehicles need to be produced in a limited size range and with uniform size distribution. The self-assembly of traditional small-molecule and polymeric amphiphiles has led to the production of micelles, liposomes, polymeric micelles, and polymersomes for use in drug delivery applications. Now,

Percec
et al.

(p.
1009
) describe the self-assembly of Janus-type (i.e., two-headed) dendrimers to produce monodisperse supramolecular constructs, termed “dendrimersomes,” and other complex architectures. The structures, which showed long-term stability as well as very narrow size distributions, were easily produced by the injection of an ethanolic solution of the dendrimer into water. The dendrimersomes could be loaded with the anticancer drug doxorubicin and exhibited controlled drug release with changing pH.
The Smart Electricity Grid and Scientific Research
Authors: Beyea Jan
Published: May 2010

Researchers have an interest in access to, and preservation of, data that will soon be collected by the smart electricity grid.
Identity Matters
Identity Economics
How Our Identities Shape Our Work, Wages, and Well-Being

by George A. Akerlof and Rachel E. Kranton

Princeton University Press, Princeton, NJ, 2010. 191 pp. $24.95, £16.95. ISBN 9780691146485.
Authors: Sugden Robert
Published: May 2010

Akerlof and Kranton argue for the importance of people's sense of identity (encompassing what is proper and what is forbidden) in understanding why individuals who face the same economic circumstances make different choices.
Salmonella
's Safety Catch
Authors: Collier R. John
Published: May 2010

Salmonella
determine when to secrete proteins into infected host cells by sensing the pH of their environment.
Banning Nuclear Tests
Authors: Corden Pierce S.
Published: May 2010

Throughout May 2010, a review of the treaty on the non-proliferation of Nuclear Weapons (NPT) is taking place at the United Nations, where its nearly 200 parties are considering the treaty's “state of health” and ways to eliminate nuclear weapons. This follows intense activity last month, in which the United States took important steps toward this goal. So it's crucial that the next important step not be missed: fully implementing the Comprehensive Nuclear-Test-Ban Treaty (CTBT). This requires U.S. ratification.
Synthetic Genome Brings New Life to Bacterium
Authors: Pennisi Elizabeth
Published: May 2010

In this week's
Science
Express, researchers
describe
the stepwise creation of a bacterial chromosome and the successful transfer of it into a bacterium, where it replaced the native DNA. Powered by the synthetic genome, that microbial cell began replicating and making a new set of proteins.
Will Britain's Coalition Wield the Funding Ax?
Authors: Clery Daniel
Published: May 2010

After 13 years of a Labour administration that greatly improved the lot of scientists, and with the government deficit at record levels, there is grave concern that research funding will be hit under Britain's new coalition government.
Former NIH Director Varmus to Head Cancer Institute
Authors: Kaiser Jocelyn
Published: May 2010

President Barack Obama announced on 17 May that he plans to appoint Nobel Prize–winning molecular biologist Harold Varmus director of the $5.1 billion National Cancer Institute.
A
Histoplasma capsulatum
-Specific IgG1 Isotype Monoclonal Antibody, H1C, to a 70-Kilodalton Cell Surface Protein Is Not Protective in Murine Histoplasmosis
Authors: Lopes Livia Cristina Liporagi , Guimarães Allan J. , de Cerqueira Mariana Duarte , Gómez Beatriz L. , Nosanchuk Joshua D.
Published: May 2010

Monoclonal antibodies to
Histoplasma capsulatum
can modify pathogenesis. We now show that monoclonal antibody H1C to a 70-kDa antigen increases intracellular fungal growth and reduces macrophage nitric oxide release but has no effect on fungal burden or survival in murine infection. This further demonstrates the complexities of host-pathogen interactions.
Evaluation of Effect of Specimen-Handling Parameters for Plasma Preparation Tubes on Viral Load Measurements Obtained by Using the Abbott RealTi
me
HIV-1 Load Assay
Authors: Fernandes Helen , Morosyuk Svetlana , Abravaya Klara , Ramanathan Madhuri , Rainen Lynne
Published: May 2010

HIV-1 viral load testing is essential to the management of HIV-1-infected patients, and proper specimen handling ensures accurate viral load (VL) results. This study was performed to (i) evaluate the effect of freezing plasma
in situ
in BD Vacutainer plasma preparation tubes (PPT) on the accuracy of HIV-1 viral load results using the Abbott RealTi
me
HIV-1 assay and (ii) evaluate the effect of whole-blood storage in the PPT for 6 h at room temperature prior to centrifugation (PPT6H) rather than 2 h as specified in the PPT product insert. Of the 64 HIV-positive subjects evaluated, 29 had average viral load counts of >40 copies/ml in at least one of the tubes tested and 35 subjects had a result of either “undetected target” or “below the limit of quantification” (LOQ) for all or some of the tubes regardless of handling condition. For the 29 subjects with VLs that were >LOQ, the mean biases between plasma from Vacutainer K
2
EDTA tubes and plasma frozen
in situ
in PPT and between K
2
EDTA tube plasma and plasma from PPT6H (log
10
copies/ml) were 0.005 and −0.001, respectively, and
r
2
was >0.92 for all correlations. We conclude that VLs determined from plasma frozen
in situ
in PPT are equivalent to VLs in K
2
EDTA tube plasma and can be used for accurate quantification of HIV-1 RNA in the Abbott RealTi
m
e HIV-1 assay. Furthermore specimens collected in PPT can be stored for 6 h at room temperature with no effect on viral load results as measured by the Abbott RealTi
m
e HIV-1 assay.
Mycobacterium haemophilum
as a Novel Etiology of Cervical Lymphadenitis in an Otherwise Healthy Adult Patient
Authors: Minani Theobald J. C. , Saubolle Michael A. , Yu Edwin , Sussland Zdenek
Published: May 2010

We describe a case and summarize six additional cases of cervical lymphadenitis in otherwise healthy adults caused by
Mycobacterium haemophilum
. The organism causes cervicofacial lymphadenitis in healthy children and severe disease in immunocompromised patients but has not been previously reported to cause cervical lymphadenitis in nonimmunocompromised, healthy adults.
Prevalence of
Salmonella enterica
in Poultry and Eggs in Uruguay during an Epidemic Due to
Salmonella enterica
Serovar Enteritidis
Authors: Betancor L. , Pereira M. , Martinez A. , Giossa G. , Fookes M. , Flores K. , Barrios P. , Repiso V. , Vignoli R. , Cordeiro N. , Algorta G. , Thomson N. , Maskell D. , Schelotto F. , Chabalgoity J. A.
Published: May 2010

Salmonella enterica
serovar Enteritidis (
S
. Enteritidis) is frequently associated with food-borne disease worldwide. Poultry-derived products are a major source. An epidemic of human infection with
S
. Enteritidis occurred in Uruguay, and to evaluate the extent of poultry contamination, we conducted a nationwide survey over 2 years that included the analysis of sera from 5,751 birds and 12,400 eggs. Serological evidence of infection with
Salmonella
group O:9 was found in 24.4% of the birds. All positive sera were retested with a gm flagellum-based enzyme-linked immunosorbent assay, and based on these results, the national prevalence of
S
. Enteritidis infection was estimated to be 6.3%. Salmonellae were recovered from 58 of 620 pools made up of 20 eggs each, demonstrating a prevalence of at least 1 in every 214 eggs. Surprisingly, the majority of the isolates were not
S
. Enteritidis. Thirty-nine isolates were typed as
S
. Derby, 9 as
S
. Gallinarum, 8 as
S
. Enteritidis, and 2 as
S
. Panama. Despite the highest prevalence in eggs,
S
. Derby was not isolated from humans in the period of analysis, suggesting a low capacity to infect humans. Microarray-based comparative genomic hybridization analysis of
S
. Derby and
S
. Enteritidis revealed more than 350 genetic differences.
S
. Derby lacked pathogenicity islands 13 and 14, the fimbrial
lpf
operon, and other regions encoding metabolic functions. Several of these regions are present not only in serovar Enteritidis but also in all sequenced strains of
S
. Typhimurium, suggesting that these regions might be related to the capacity of
Salmonella
to cause food-borne disease.
Enhancement of Autophagy during Lytic Replication by the Kaposi's Sarcoma-Associated Herpesvirus Replication and Transcription Activator
Authors: Wen Hui-Ju , Yang Zhilong , Zhou You , Wood Charles
Published: May 2010

Autophagy is one of two major degradation systems in eukaryotic cells. The degradation mechanism of autophagy is required to maintain the balance between the biosynthetic and catabolic processes and also contributes to defense against invading pathogens. Recent studies suggest that a number of viruses can evade or subvert the host cell autophagic pathway to enhance their own replication. Here, we investigated the effect of autophagy on the KSHV (Kaposi's sarcoma-associated herpesvirus) life cycle. We found that the inhibition of autophagy reduces KSHV lytic reactivation from latency, and an enhancement of autophagy can be detected during KSHV lytic replication. In addition, RTA (replication and transcription activator), an essential viral protein for KSHV lytic reactivation, is able to enhance the autophagic process, leading to an increase in the number of autophagic vacuoles, an increase in the level of the lipidated LC3 protein, and the formation of autolysosomes. Moreover, the inhibition of autophagy affects RTA-mediated lytic gene expression and viral DNA replication. These results suggest that RTA increases autophagy activation to facilitate KSHV lytic replication. This is the first report demonstrating that autophagy is involved in the lytic reactivation of KSHV.
Cellular Transcription Factor ZASC1 Regulates Murine Leukemia Virus Transcription
Authors: Bruce James W. , Hierl Michael , Young John A. T. , Ahlquist Paul
Published: May 2010

To identify cellular processes involved in retroviral infection, we employed a high-volume forward genetic screen of insertionally mutagenized somatic cells using a murine leukemia virus (MLV) vector. This approach identified a clonal cell line that exhibited approximately 10-fold reduced gene expression from MLV vectors following infection despite supporting normal levels of MLV reverse transcription and integration. The defect in this cell line was specific for the MLV long terminal repeat (LTR) promoter, as normal levels of reporter gene expression were obtained from both an internal cytomegalovirus (CMV) promoter contained within an LTR-defective MLV vector and LTR expression from an avian sarcoma and leukosis virus (ASLV) vector. Complementation and shRNA knockdown experiments demonstrated that the defective gene in these cells is ZASC1 (ZNF639), a transcription factor with strong links to cancer and inherited ataxias. We demonstrated that ZASC1 is a sequence-specific DNA binding protein with three closely related binding sites located within the MLV LTR promoter, but it does not bind to the ASLV promoter. Mutating these putative ZASC1 binding sites significantly reduced levels of MLV gene expression. While wild-type ZASC1 activated expression from the MLV promoter, a green fluorescent protein-ZASC1 fusion protein showed dominant-negative inhibition of MLV gene expression. These studies identify the cellular transcription factor ZASC1 as an activator of MLV gene expression and provide tools that should be useful in studying the links between ZASC1 and human diseases.
Structural Basis for the Inhibition of RNase H Activity of HIV-1 Reverse Transcriptase by RNase H Active Site-Directed Inhibitors
Authors: Su Hua-Poo , Yan Youwei , Prasad G. Sridhar , Smith Robert F. , Daniels Christopher L. , Abeywickrema Pravien D. , Reid John C. , Loughran H. Marie , Kornienko Maria , Sharma Sujata , Grobler Jay A. , Xu Bei , Sardana Vinod , Allison Timothy J. , Williams Peter D. , Darke Paul L. , Hazuda Daria J. , Munshi Sanjeev
Published: May 2010

HIV/AIDS continues to be a menace to public health. Several drugs currently on the market have successfully improved the ability to manage the viral burden in infected patients. However, new drugs are needed to combat the rapid emergence of mutated forms of the virus that are resistant to existing therapies. Currently, approved drugs target three of the four major enzyme activities encoded by the virus that are critical to the HIV life cycle. Although a number of inhibitors of HIV RNase H activity have been reported, few inhibit by directly engaging the RNase H active site. Here, we describe structures of naphthyridinone-containing inhibitors bound to the RNase H active site. This class of compounds binds to the active site via two metal ions that are coordinated by catalytic site residues, D443, E478, D498, and D549. The directionality of the naphthyridinone pharmacophore is restricted by the ordering of D549 and H539 in the RNase H domain. In addition, one of the naphthyridinone-based compounds was found to bind at a second site close to the polymerase active site and non-nucleoside/nucleotide inhibitor sites in a metal-independent manner. Further characterization, using fluorescence-based thermal denaturation and a crystal structure of the isolated RNase H domain reveals that this compound can also bind the RNase H site and retains the metal-dependent binding mode of this class of molecules. These structures provide a means for structurally guided design of novel RNase H inhibitors.
The Proteasome Inhibitor Velcade Enhances rather than Reduces Disease in Mouse Hepatitis Coronavirus-Infected Mice
Authors: Raaben Matthijs , Grinwis Guy C. M. , Rottier Peter J. M. , de Haan Cornelis A. M.
Published: May 2010

Many viruses, including coronaviruses (CoVs), depend on a functional cellular proteasome for efficient infectionin vitro. Hence, the proteasome inhibitor Velcade (bortezomib), a clinically approved anticancer drug, shown in an accompanying study (M. Raaben et al., J. Virol. 84:7869-7879, 2010) to strongly inhibit mouse hepatitis CoV (MHV) infection in cultured cells, seemed an attractive candidate for testing its antiviral propertiesin vivo. Surprisingly, however, the drug did not reduce replication of the virus in mice. Rather, inhibition of the proteasome caused enhanced infection with lethal outcome, calling for caution when using this type of drug during infection.
Potential for the
Anopheles gambiae
Densonucleosis Virus To Act as an “Evolution-Proof” Biopesticide
Authors: Ren Xiaoxia , Rasgon Jason L.
Published: May 2010

“Evolution-proof” or “late-life-acting” insecticides (LLAIs) preferentially kill older adult mosquitoes and are of extreme interest to control vector-borne diseases such as malaria. We used quantitative PCR to assess whether the
Anopheles gambiae
densonucleosis virus (AgDNV) had potential as an LLAI. After infection, AgDNV titers increased modestly during larval development but replicated slower than the host cells, resulting in a significant decrease in the normalized virus titer during larval and pupal development. Normalized virus titers dramatically increased after adult emergence, peaking in 7- to 10-day-old adults. Unlike other DNVs, AgDNV does not significantly replicate in preadult mosquitoes but rather preferentially replicates in older adults. The natural dynamics of AgDNV make it ideal for expression of insect-specific toxin genes as a biological LLAI.
Congregation of Orthopoxvirus Virions in Cytoplasmic A-Type Inclusions Is Mediated by Interactions of a Bridging Protein (A26p) with a Matrix Protein (ATIp) and a Virion Membrane-Associated Protein (A27p)
Authors: Howard Amanda R. , Weisberg Andrea S. , Moss Bernard
Published: May 2010

Some orthopoxviruses, e.g., the cowpox, ectromelia, and raccoonpox viruses, form large, discrete cytoplasmic inclusions within which mature virions (MVs) are embedded by a process called occlusion. These inclusions, which may protect occluded MVs in the environment, are composed of aggregates of the A-type inclusion protein (ATIp), which is truncated in orthopoxviruses such as vaccinia virus (VACV) and variola virus that fail to form inclusions. In addition to an intact ATIp, occlusion requires the A26 protein (A26p). Although VACV contains a functional A26p, determined by complementation of a cowpox virus occlusion-defective mutant, its role in occlusion was unknown. We found that restoration of the full-length ATI gene was sufficient for VACV inclusion formation and the ensuing occlusion of MVs. A26p was present in inclusions even when virion assembly was inhibited, suggesting a direct interaction of A26p with ATIp. Analysis of a panel of ATIp mutants indicated that the C-terminal repeat region was required for inclusion formation and the N-terminal domain for interaction with A26p and occlusion. A26p is tethered to MVs via interaction with the A27 protein (A27p); A27p was not required for association of A26p with ATIp but was necessary for occlusion. In addition, the C-terminal domain of A26p, which mediates A26p-A27p interactions, was necessary but insufficient for occlusion. Taken together, the data suggest a model for occlusion in which A26p has a bridging role between ATIp and A27p, and A27p provides a link to the MV membrane.
Autographa californica
Multiple Nucleopolyhedrovirus
ac76
Is Involved in Intranuclear Microvesicle Formation
Authors: Hu Zhaoyang , Yuan Meijin , Wu Wenbi , Liu Chao , Yang Kai , Pang Yi
Published: May 2010

In this study, we characterized
Autographa californica
multiple nucleopolyhedrovirus (AcMNPV)
orf76
(
ac76
), which is a highly conserved gene of unknown function in lepidopteran baculoviruses. Transcriptional analysis of
ac76
revealed that transcription of multiple overlapping multicistronic transcripts initiates from a canonical TAAG late-transcription start motif but terminates at different 3′ ends at 24 h postinfection in AcMNPV-infected Sf9 cells. To investigate the role of
ac76
in the baculovirus life cycle, an
ac76
-knockout virus was constructed using an AcMNPV bacmid system. Microscopy, titration assays, and Western blot analysis demonstrated that the resulting
ac76
-knockout virus was unable to produce budded viruses. Quantitative real-time PCR analysis demonstrated that
ac76
deletion did not affect viral DNA synthesis. Electron microscopy showed that virus-induced intranuclear microvesicles as well as occlusion-derived virions were never observed in cells transfected with the
ac76
-knockout virus. Confocal microscopy analysis revealed that Ac76 was predominantly localized to the ring zone of nuclei during the late phase of infection. This suggests that
ac76
plays a role in intranuclear microvesicle formation. To the best of our knowledge, this is the first baculovirus gene identified to be involved in intranuclear microvesicle formation.
Tyrosine Residues in the Cytoplasmic Domains Affect Sorting and Fusion Activity of the Nipah Virus Glycoproteins in Polarized Epithelial Cells
Authors: Weise Carolin , Erbar Stephanie , Lamp Boris , Vogt Carola , Diederich Sandra , Maisner Andrea
Published: May 2010

The highly pathogenic Nipah virus (NiV) is aerially transmitted and causes a systemic infection after entering the respiratory tract. Airway epithelia are thus important targets in primary infection. Furthermore, virus replication in the mucosal surfaces of the respiratory or urinary tract in later phases of infection is essential for virus shedding and transmission. So far, the mechanisms of NiV replication in epithelial cells are poorly elucidated. In the present study, we provide evidence that bipolar targeting of the two NiV surface glycoproteins G and F is of biological importance for fusion in polarized epithelia. We demonstrate that infection of polarized cells induces focus formation, with both glycoproteins located at lateral membranes of infected cells adjacent to uninfected cells. Supporting the idea of a direct spread of infection via lateral cell-to-cell fusion, we could identify basolateral targeting signals in the cytoplasmic domains of both NiV glycoproteins. Tyrosine 525 in the F protein is part of an endocytosis signal and is also responsible for basolateral sorting. Surprisingly, we identified a dityrosine motif at position 28/29 in the G protein, which mediates polarized targeting. A dileucine motif predicted to function as sorting signal is not involved. Mutation of the targeting signal in one of the NiV glycoproteins prevented the fusion of polarized cells, suggesting that basolateral or bipolar F and G expression facilitates the spread of NiV within epithelial cell monolayers, thereby contributing to efficient virus spread in mucosal surfaces in early and late phases of infection.
Avian Reovirus Nonstructural Protein p17-Induced G
2
/M Cell Cycle Arrest and Host Cellular Protein Translation Shutoff Involve Activation of p53-Dependent Pathways
Authors: Chulu Julius L. C. , Huang Wei R. , Wang L. , Shih Wen L. , Liu Hung J.
Published: May 2010

The effects of avian reovirus (ARV) p17 protein on cell cycle progression and host cellular protein translation were studied. ARV infection and ARV p17 transfection resulted in the accumulation of infected and/or transfected cells in the G
2
/M phase of the cell cycle. The accumulation of cells in the G
2
/M phase was accompanied by upregulation and phosphorylation of the G
2
/M-phase proteins ATM, p53, p21
cip1/waf1
, Cdc2, cyclin B1, Chk1, Chk2, and Cdc25C, suggesting that p17 induces a G
2
/M cell cycle arrest through activation of the ATM/p53/p21
cip1/waf1
/Cdc2/cyclin B1 and ATM/Chk1/Chk2/Cdc25C pathways. The G
2
/M cell cycle arrest resulted in increased virus replication. In the present study, we also provide evidence demonstrating that p17 protein is responsible for ARV-induced host cellular protein translation shutoff. Increased phosphorylation levels of the eukaryotic translation elongation factor 2 (eEF2) and initiation factor eIF2α and reduced phosphorylation levels of the eukaryotic translation initiation factors eIF4E, eIF4B, and eIF4G, as well as 4E-BP1 and Mnk-1 in p17-transfected cells, demonstrated that ARV p17 suppresses translation initiation factors and translation elongation factors to induce host cellular protein translation shutoff. Inhibition of mTOR by rapamycin resulted in a decrease in the levels of phosphorylated 4E-BP1, eIF4B, and eIF4G and an increase in the levels eEF2 but did not affect ARV replication, suggesting that ARV replication was not hindered by inhibition of cap-dependent translation. Taken together, our data indicate that ARV p17-induced G
2
/M arrest and host cellular translation shutoff resulted in increased ARV replication.
Force field for in-plane vibrations of terephthalonitrile
Authors: Arenas Juan F. , Marcos Juan I. , Ramírez Francisco J.
Published: May 2010

The general quadratic force field for the in-plane vibrations of terephthalonitrile was calculated by the semi-empirical MINDO/3 method. This force field was refined to the frequencies observed experimentally for terephthalonitrile and isotopic shifts of terephthalonitrile-[15N2]. The refined frequencies reproduce the experimental data with errors less than 0.5%. The normal coordinates and the force field in internal coordinates were also calculated from the refined field.
Electroanalytical chemistry of vanadium complexes. Comparison of the voltammetric features of amavadine with those of the vanadium complexes with iminodiacetic acid and methyliminodiacetic acid
Authors: Meier Roland , Frank Harald , Kirmse Reinhard , Salzer Reiner , Stach Joachim , Werner Gerhard , Otto Matthias
Published: May 2010

The voltammetric behaviour of amavadine (AV) was found to be considerably different from that of the complexes of VO2+ with methyliminodiacetic acid (MIDA) and iminodiacetic acid (IDA). To get an insight in the rather complicated reduction mechanism of the latter complexes the reductions of V(III) (MIDA) and V(III) (IDA) have been studied for comparison. The species V(III) (MIDA)2 and V(III) (IDA)2 are reduced to the appropriate V(II) complexes in a chemically reversible process. VO(MIDA)2 and VO(IDA)2 are reduced to the same complexes via an ECE mechanism. The investigation of the electroreduction of AV shows that this process is not reversible in the chemical sense. As a probable explanation, the conclusion was drawn that AV and the usual V(IV)O-iminocarboxylato complexes differ in their structures.
Ultrafiltration of silica sols
Authors: Stakić Milan , Milonjić Slobodan , Pavasović Vladeta , Ilić Zoja
Published: May 2010

Ultrafiltration of three laboratory made silica and two commercial silica sols was studied using Amicon YC membrane in a 200 ml capacity batch-cell. The effect of silica particle size, stirring conditions, pressure, pH and silica contents on ultrafiltration was investigated. The results obtained indicate that the smaller particles have, disregarding the stirring conditions, lower filtration flux. The differences observed in filtration flux are more pronounced in the conditions without stirring. The obtained value of the membrane resistance is independent of the conditions investigated (stirring, pressure, pH, silica contents and particle size). The values of the resistance of polarized solids, specific resistance, and the mass of gel per membrane surface unit were calculated for all experimental conditions.
Determination of the absolute configuration of secondary alcohols by modified Horeau's method using HPLC
Authors: Svatoš Aleš , Valterová Irena , Fábryová Anna , Vrkoč Jan
Published: May 2010

A method for determination of absolute configuration of secondary alcohols, based on a modified Horeau's method, has been developed. The ratio of (1R,2'S)- and (1R,2'R)-N-[1-(1-naphthyl)-ethyl]-2-phenylbutanamides (V and VI, respectively) was determined by HPLC on a straight phase. The method was tested on a series of steroid and terpene model compounds and was used in the determination of absolute configuration of 15-ripperten-3α-ol (XV), the defense substance of Nasutitermes nigriceps termites. The sensibility of the determination is 100 nmol of the alcohol.
Free chymotrypsin-catalyzed synthesis of peptide bond in aliphatic alcohols with low water content
Authors: Čeřovský Václav , Martinek Karel
Published: May 2010

The effect of water content on free chymotrypsin-catalyzed reaction of Ac-Tyr-OEt with HBr.Gly-NH2 in triethylamine-containing 2-propanol was studied. Maximum yield of dipeptide Ac-Tyr-Gly-NH2 was obtained in 2-propanol with 2% of water. Lower water content retards the reaction. Although higher water content accellerates the process, the yield of the dipeptide is reduced by enzymatically catalyzed hydrolysis of Ac-Tyr-OEt. The studied reaction proceeds analogously also in other aliphatic alcohols woth low content of water except in methanol; it does not take place in dimethylformamide or dimethyl sulfoxide containing 2% or 20% of water. In 2-propanol with 2% or 5% of water, syntheses of the protected amino-terminal oxytocine and vasopressin tripeptide, as well as other model peptides, were studied. In all the described experiments, α-chymotrypsin without any stabilization or immobilization was employed.
Reduction of thermodynamic constitutive equations for fluid mixtures using form invariance
Authors: Samohýl Ivan
Published: May 2010

Balances of mass, momentum and its moment, energy, and entropy in Truesdell's model of n-constituent mixtures have the property of form invariance: a certain change of primitive properties by means of 2n-1 arbitrary quantities does not cause a change in their form. This arbitrariness can be used to make also the constitutive equations for partial thermodynamic quantities independent of the transport quantities (e.g. on temperature gradients or deformation rates). The classical method of Coleman and Noll used in rational thermodynamics of fluid mixtures namely permits to obtain such an independence with constitutive equations for thermodynamic quantities of mixtures only, and not for the partial quantities.
Ab initio study of the configuration and protonation of thiocarbamic acid
Authors: Remko Milan
Published: May 2010

The ab initio SCF method was applied to a conformation study of thiocarbamic acid. The 3-21 G calculations revealed that the trans isomer with the O-H···S intramolecular hydrogen bond is more stable than the cis isomer. The calculated rotational barrier for the rotation about the central C-N bond is very high, 125.5 kJ mol-1; this value, however, decreased to 106.2 kJ mol-1 by electron correlation determined at the 2nd order Moller-Plesset perturbation level. Proton affinities for the protonation of the electronegative atoms in the acid increase in the order of the atoms N, O and S. Changes in the Mulliken gross atomic populations are examined in dependence on the configuration and protonation of the acid.
Determination of the density of solids by means of a solid pycnometric substance
Authors: Medek Jiří , Weishauptová Zuzana
Published: May 2010

A new method has been developed for determination of apparent density of porous powdered materials, which uses a suitable plastic solid substance as the pycnometric medium. In this method a mixture of the tested and pycnometric substances is compressed in a pressing device up to the pressure, at which the pycnometric substance undergoes plastic deformation and fills completely all intergranular voids between particles of the tested material. The rheologic properties of the pycnometric substance prevent its penetration into coarse pores, which makes the method especially suitable for determination of apparent density of coarsely porous materials. The method can be used also for determination of true density of non-porous powdered materials.
An infrared study of interactions in the system sodium tert-butoxide-tetrahydrofuran
Authors: Matějka Libor , Lochmann Lubomír , Schmidt Pavel
Published: May 2010

The adduct of sodium tert-butoxide (t-BuONa) with tetrahydrofuran (THF) was studied by measuring changes of infrared spectra in the range 900-1100 cm-1. Alkoxide autoassociation and solvation of this associate by tetrahydrofuran play a role in adduct formation. In hydrocarbon solvents in the presence of minor amounts of THF, higher t-BuONa associates are dissociated, the preffered form being a tetramer solvated by three THF molecules. At large excess of THF, the tetramer is solvated by four THF molecules. The stability constant of the adduct, referred to one Na-O bond, is 5.01.
Kinetics of ethylbenzene hydrogenolytic dealkylation on Ni-Al2O3 catalyst
Authors: Uk Kim Chong , Jeřábek Karel , Prokop Zdeněk , Setínek Karel
Published: May 2010

Kinetic equation was found for dealkylation of ethylbenzene at the presence of hydrogen on a Ni-Al2O3 catalyst at 330 °C which indicates a complicated course of this vapor phase catalytic reaction. Similar character of reaction course showed also the demethylation of toluene on the same kind of catalyst and at the same reaction conditions. These results differ from results obtained for this reaction previously.
Continuous monitoring of ammonia in the atmosphere using an aerodisperse enrichment unit
Authors: Večeřa Zbyněk , Janák Jaroslav , Pisca Stanislav , Rezbárik Jan
Published: May 2010

Continuous monitoring of low concentrations of ammonia in the gas phase is described. The rather low limit of detection is achieved by the absorption of ammonia from the atmosphere in the polydispersed aerosol of water and by the selective detection of ammonia in the concentrate by means of the gas-phase ion-selective NH3-electrode (ISE-NH3). The worked out monitor is computer-controlled and it was used in the veterinary service for testing the microclima of buildings for agricultural use. The reliability of the method was checked by the reference standard method.
Evaluation of colour changes of screened acid-base indicators
Authors: Lemr Karel , Kotouček Milan
Published: May 2010

Based on computer-assisted calculations, six screened indicators were prepared and used for visual titration end point indication. Three of them were evaluated in terms of objective colour characteristics. Their colour changes were characterized in the CIE-xy (1931) international colorimetric system, by the Helmholtz coordinates, complementary Qx, Qy coordinates, perceptibility and course of the ΔJ/ΔpH = f(pH) function. In addition, new indices were introduced, viz. partial quality indices IE, Ip and Im, related with the colour difference between the two indicator species (IE), their colour purity (Ip) and the experimenter's ability to remember the colour in the titration end point (Im). Summed up, the three indices constitute the total quality index of the chemical indicator It. These indices were employed for comparing the single and the corresponding screened indicators.
Spectrophotometric and polarographic study of the efficiency of the chemical destruction of some antineoplastic pharmaceuticals
Authors: Barek Jiří , Zima Jiří
Published: May 2010

The efficiency of the chemical destruction of some antineoplastic pharmaceuticals was studied using visible and ultraviolet spectrophotometry and differential pulse polarography. Doxorubicin, Daunorubicin, Vincristine, Vinblastine, Methotrexate and Dichlomethotrexate are destroyed best by oxidatin with potassium permanganate, while some derivatives of N-nitrosourea (Lomustine, Chlorozotocin) are best destroyed by denitrosation with hydrobromic acid. The efficiency of the decomposition can readily be studied by spectrophotometry or differential pulse polarography.
Voltammetric determination of trace amounts of aluminium
Authors: Stará Věra , Kopanica Miloslav
Published: May 2010

Aluminium is determined voltammetrically in the form of the aluminium complex with Acid Alizarin Violet N in an acetate buffer of pH 5.2 using a hanging mercury drop electrode and the d.c. or differential pulse technique. A linear dependence between the peak current and the aluminium concentration was obtained in the range from 2.10-8 to 5.10-6 mol l-1. The interfering effect of copper, lead and cadmium is eliminated by the auxiliary complex forming reagent-glycine.
Optimal catalyst activity distribution in fixed-bed reactor with catalyst deactivation
Authors: Markoš Jozef , Brunovská Alena
Published: May 2010

In this paper the influence of the active catalyst location in a pellet on fixed-bed catalytic reactor performance is described. The optimal activity distribution as a function of an economic parameter (ratio of product and catalyst costs), Thiele modulus and Damkohler number is estimated.
Estimation of the catalyst pellet activity distribution from experimental kinetic data
Authors: Brunovská Alena , Remiarová Bibiana , Lebrun Carlo
Published: May 2010

In this paper a method of catalyst pellet activity distribution estimation from experimental kinetic data is described. Measurements of outlet concentration from a laboratory continuous stirred single-pellet reactor vs feed rate for ethylene hydrogenation on Pt/alumina pellet are used as kinetic data. To find the best estimate the gradient method is employed and the gradient is computed with the help of the adjoint equation. The estimated activity distribution is compared with the Pt distribution obtained by the scanning electron microscope.
Acid-catalyzed rearrangements of an A(1)-nor-triterpenoid 2α,3α-epoxide
Authors: Klinot Jiří , Liška Jiří , Forgáčová Alena , Buděšínský Miloš , Protiva Jiří , Hilgard Stanislav , Vystrčil Alois
Published: May 2010

Reactions of 2α,3α-epoxide X, derived from 19β,28-epoxy-A(1)-nor-18α-oleanane, with acids proceed with migration of the 10β-methyl group into the position 2β, giving rise to unsaturated alcohols XII and XIV and diene IX. Reaction with boron trifluoride etherate afforded ketone XI in addition to XII and XIV. Olefin VIII rearranged in acidic medium to give olefins XXVI and XXVII. The rearranged products were converted into other derivatives and their structure was established by 1H and 13C NMR, IR, UV and mass spectra.
Formation of spiro adduct from N-methyl-N-(2,4,6-trinitrophenyl)glycine anion
Authors: Macháček Vladimír , Čegan Alexandr , Sedlák Miloš , Štěrba Vojeslav
Published: May 2010

The intramolecular nucleophilic addition of N-methyl-N-(2,4,6-trinitrophenyl)glycine anion in methanol-dimethyl sulfoxide mixtures produces spiro[(3-methyl-5-oxazolidinone)-2,1'-(2',4',6'-trinitrobenzenide)]. The spiro adduct has been identified by means of 1H and 13C NMR spectroscopy. This is the first case when the formation of a Meisenheimer adduct with carboxylate ion is observed. Logarithm of the equilibrium constant of adduct formation increases linearly with the mole fraction of dimethyl sulfoxide in its mixture with methanol.
Study of conformation of α-narcotine N-oxide and related compounds
Authors: Uhrín Dušan , Proksa Bohumil
Published: May 2010

Conformation of quaternary derivatives of (-)-α-narcotine (I) in solution was investigated using α-narcotine N-oxide hydrochloride (IV) as the model compound. In solution, compound IV exists predominantly in the form with torsion angle H-C(1)-C(9)-H of about 270° and with half-chair conformation of the isoquinoline tetrahydropyridine ring.
Synthesis and antimicrobial activity of some 3-oxo-3H-pyrido[3,2,1-kl]phenoxazine-2-carboxylic acids
Authors: Rádl Stanislav , Zikán Viktor
Published: May 2010

Reaction of ethyl 1,4-dihydro-8-hydroxy-4-oxo-3-quinolinecarboxylates XIIIa-XIIIc with 2,4-dinitrochlorobenzene in N,N-dimethylformamide in the presence of sodium hydrogen carbonate yields appropriate ethyl 3-oxo-3H-pyrido[3,2,1-kl]phenoxazine-2-carboxylates XIVa-XIVc. Similar reaction of XIIIa and XIIIb in aqueous solution yields mixtures of the respective ester (XIVa and XIVb, respectively) and acid (XIVd and XIVe, respectively). Compounds XIVg-XIVj were prepared by usual methods. The compounds prepared were tested for their antimicrobial activity in vitro.
Automated chloridite and amidite synthesis of oligodeoxyribonucleotides on a long chain support using amidine protected purine nucleosides
Authors: Arnold Luboš , Točík Zdeněk , Bradková Eliška , Hostomský Zdeněk , Pačes Václav , Smrt Jiří
Published: May 2010

Preparation of solid supports with long aliphatic spacer for the oligonucleotide synthesis is described. Automated synthesis of oligodeoxyribonucleotides using in situ prepared methylchlorophosphite intermediates from amidine protected purine nucleosides is described. Phosphoramidite synthesis of oligodeoxyribonucleotides mediated by 1-methylimidazole trifluoromethanesulfonate is described. Novel isolation of crude oligonucleotides by ethanol precipitation of potassium salts is described.
Polarographic studies on renaturation of urea-denatured human serum albumin
Authors: Chmelík Josef , Anzenbacher Pavel , Kalous Vítěz
Published: May 2010

The renaturation of the two main components of human serum albumin, i.e. of mercaptalbumin and nonmercaptalbumin, was studied polarographically. It has been demonstrated that renaturation of both proteins after 1-min denaturation in 8M urea is reversible. By contrast, renaturation after 200 min denaturation in 8M urea is an irreversible process; the characteristics of renatured mercaptalbumin differ more from the properties of the native protein than the characteristics of nonmercaptalbumin. The studies of the kinetics of renaturation of both proteins have shown that the renaturation can be represented by a two-state model. This means that the existence of stable intermediary products during the renaturation process was not determined polarographically.
Adsorption of carbon monoxide on the iridium fcc (112) surface: Topological study
Authors: Pancíř Jiří , Haslingerová Ivana
Published: May 2010

A semi-empirical topological method was applied to a study of an Ir(112) surface as well as to both a nondissociative and dissociative chemisorption on this surface. In all cases studied an attachment of carbon to the surface is energetically more favorable than an attachment of oxygen. The preferential capture of the CO molecule on atop sites is remarkable. The capture on n-fold hollow positions as well as the dissociative chemisorption of carbon monoxide on the Ir(112) surface are energetically prohibited.