bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic Evolution of the Spanish Multidrug-Resistant
Salmonella enterica
4,5,12:i:- Monophasic Variant
Authors: Laorden Lorena , Herrera-León Silvia , Martínez Ilargi , Sanchez Ainhoa , Kromidas Lefteris , Bikandi Joseba , Rementeria Aitor , Echeita Aurora , Garaizar Javier
Published: October 2010

We analyzed a collection of 60
Salmonella enterica
4,5,12:i:- phage type U302 multidrug-resistant monophasic variant strains, isolated in Spain between 2000 and 2007. Most strains showed resistance to ampicillin (A), chloramphenicol (C), sulfamethoxazole (Su), gentamicin (G), streptomycin (S), tetracycline (T), and co-trimoxazole (SxT) (an ACSuGSTSxT resistance pattern). Only one pulsed-field gel electrophoresis (PFGE) type was detected, with 19 subtypes (Simpson's index of diversity [SID] = 0.89). Multiple-locus variable-number tandem-repeat analysis (MLVA) showed more variability, with 32 profiles (SID = 0.97), but only showed diversity at the STTR5 and STTR6 loci. PCR and sequencing demonstrated all strains contained the same allantoin-glyoxylate pathway deletion. Four types of deletions were detected in the
fljAB
operon, all starting at the same position, at the STM2758 gene, and followed by an IS
26
insertion. Furthermore, a representative set of strains of the four deletion types harbored plasmids with IS
26
. We propose that a
Salmonella enterica
serotype Typhimurium U302 multidrug-resistant (ACSuGSTSxT) strain, defective for the allantoin-glyoxylate pathway and containing IS
26
at plasmid pU302L, could be the ancestor of the variant in Spain.
Novel Multiplex PCR Using Dual-Priming Oligonucleotides for Detection and Discrimination of the
Mycobacterium tuberculosis
Complex and
M. bovis
BCG
Authors: Lee Hye Ryun , Kim So Yeon , Chang Ho Eun , Song Sang Hoon , Lee Hye Seung , Park Kyoung Un , Song Junghan , Kim Eui-Chong
Published: October 2010

We developed a novel multiplex PCR assay using dual-priming oligonucleotide primers targeting the
RD1
gene for simultaneous identification of the
Mycobacterium tuberculosis
complex and
M. bovis
bacillus Calmette-Guérin (BCG). This assay would be useful both for detection of the
M. tuberculosis
complex and for differentiation of
M. bovis
BCG from pathogenic
M. tuberculosis
complex species.
Innovation for Reducing Blood Culture Contamination: Initial Specimen Diversion Technique
Authors: Patton Richard G. , Schmitt Timothy
Published: October 2010

We hypothesized that diversion of the first milliliter of venipuncture blood—the initial specimen diversion technique (ISDT)—would eliminate incompletely sterilized fragments of skin from the culture specimen and significantly reduce our blood culture contamination rate (
R
). We studied our hypothesis prospectively beginning with our control culture (C) definition: one venipuncture with two sequentially obtained specimens, 10 ml each, the first specimen (M1) for aerobic and the second (M2) for anaerobic media. The test ISDT culture (D) was identical, with the exception that each was preceded by diverting a 1-ml sample (D
S
) from the same venipuncture. During the first of two sequential 9-month periods, we captured D versus C data (
n
= 3,733), where D
MX
R
and C
MX
R
are
R
for D and C specimens. Our hypothesis predicted D
S
would divert soiled skin fragments from D
M1
, and therefore, C
M1
R
would be significantly greater than D
M1
R
. This was confirmed by C
M1
R
(30/1,061 [2.8%]) less D
M1
R
(37/2,672 [1.4%];
P
= 0.005), which equals 1.4%. For the second 9-month follow-up period, data were compiled for all cultures (
n
= 4,143), where AD
MX
R
is
R
for all (A) diversion specimens, enabling comparison to test ISDT. Our hypothesis predicted no significant differences for test ISDT versus all ISDT. This was confirmed by D
M 1
R
(37/2,672 [1.4%]) versus AD
M 1
R
(42/4,143 [1.0%];
P
= 0.17) and D
M2
R
(21/2,672 [0.80%]) versus AD
M2
R
(39/4,143 [0.94%];
P
= 0.50). We conclude that our hypothesis is valid: venipuncture needles soil blood culture specimens with unsterilized skin fragments and increase
R
, and ISDT significantly reduces
R
from venipuncture-obtained blood culture specimens.
Performance of Commercial Enzyme-Linked Immunosorbent Assays for Detection of Antibodies to
Bordetella pertussis
Authors: Riffelmann M. , Thiel K. , Schmetz J. , Wirsing von Koenig C. H.
Published: October 2010

Measuring antibodies to
Bordetella pertussis
antigens is mostly done by enzyme-linked immunosorbent assays (ELISAs). We compared the performance of ELISA kits that were commercially available in Germany. Eleven measured IgG antibodies, and nine measured IgA antibodies. An in-house ELISA with purified antigens served as a reference method. Samples included two WHO reference preparations, the former Food and Drug Administration (FDA)/Center for Biologics Evaluation and Research (CBER) reference preparations, serum samples from patients with clinically suspected pertussis, and serum samples from patients having received a combined tetanus, diphtheria, and pertussis (Tdap) vaccination. Kits using pertussis toxin (PT) as an antigen showed linearity compared to the WHO Reference preparation (
r
2
between 0.82 and 0.99), and these kits could quantify antibodies according to the reference preparation. ELISA kits using mixed antigens showed no linear correlation to the reference preparations. Patient results were compared to results of in-house ELISAs using a dual cutoff of either ≥100 IU/ml anti-PT IgG or ≥40 IU/ml anti-PT IgG together with ≥12 IU/ml anti-PT IgA. The sensitivities of kits measuring IgG antibodies ranged between 0.84 and 1.00. The specificities of kits using PT as an antigen were between 0.81 and 0.93. The specificities of kits using mixed antigens were between 0.51 and 0.59 and were thus not acceptable. The sensitivities of kits measuring IgA antibodies ranged between 0.53 and 0.73, and the specificities were between 0.67 and 0.94, indicating that IgA antibodies may be of limited diagnostic value. Our data suggest that ELISAs should use purified PT as an antigen and be standardized to the 1st International Reference preparation.
Rapid Identification of Mycobacterial Whole Cells in Solid and Liquid Culture Media by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry
Authors: Lotz Aurélie , Ferroni Agnès , Beretti Jean-Luc , Dauphin Brunhilde , Carbonnelle Etienne , Guet-Revillet Hélène , Veziris Nicolas , Heym Béate , Jarlier Vincent , Gaillard Jean-Louis , Pierre-Audigier Catherine , Frapy Eric , Berche Patrick , Nassif Xavier , Bille Emmanuelle
Published: October 2010

Mycobacterial identification is based on several methods: conventional biochemical tests that require several weeks for accurate identification, and molecular tools that are now routinely used. However, these techniques are expensive and time-consuming. In this study, an alternative method was developed using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). This approach allows a characteristic mass spectral fingerprint to be obtained from whole inactivated mycobacterial cells. We engineered a strategy based on specific profiles in order to identify the most clinically relevant species of mycobacteria. To validate the mycobacterial database, a total of 311 strains belonging to 31 distinct species and 4 species complexes grown in Löwenstein-Jensen (LJ) and liquid (mycobacterium growth indicator tube [MGIT]) media were analyzed. No extraction step was required. Correct identifications were obtained for 97% of strains from LJ and 77% from MGIT media. No misidentification was noted. Our results, based on a very simple protocol, suggest that this system may represent a serious alternative for clinical laboratories to identify mycobacterial species.
Evaluation of the Cepheid Xpert
Clostridium difficile
Epi Assay for Diagnosis of
Clostridium difficile
Infection and Typing of the NAP1 Strain at a Cancer Hospital
Authors: Babady N. Esther , Stiles Jeffrey , Ruggiero Phyllis , Khosa Perminder , Huang David , Shuptar Susan , Kamboj Mini , Kiehn Timothy E.
Published: October 2010

Clostridium difficile
is the most common cause of health care-associated diarrhea. Accurate and rapid diagnosis is essential to improve patient outcome and prevent disease spread. We compared our two-step diagnostic algorithm, an enzyme immunoassay for glutamate dehydrogenase (GDH) followed by the cytotoxin neutralization test (CYT) with a turnaround time of 24 to 48 h, versus the Cepheid Xpert
C. difficile
Epi assay, a PCR-based assay with a turnaround time of <1 h. In the first phase of the study, only GDH-positive stool samples were tested by both CYT and Xpert PCR. Discordant results were resolved by toxigenic culture. In the second phase, all stool samples were tested by GDH and Xpert PCR. Only GDH-positive stools were further tested by CYT. Genotypic characterization of 45 Xpert PCR-positive stools was performed by sequencing of the
tcdC
gene and PCR ribotyping. In phase 1, the agreement between the GDH-CYT and the GDH-Xpert PCR was 72%. The sensitivities and specificities of GDH-CYT and GDH-Xpert PCR were 57% and 97% and 100% and 97%, respectively. In phase 2, the agreement between GDH-CYT and Xpert PCR alone was 95%. As in phase 1, sensitivity of the Xpert PCR was higher than that of the GDH-CYT. The correlation between PCR-ribotyping, sequencing, and Xpert PCR for detection of NAP1 strains was excellent (>90%). The excellent sensitivity and specificity and the rapid turnaround time of the Xpert PCR assay as well as its strain-typing capability make it an attractive option for diagnosis of
C. difficile
infection.
Cationic Lipid/DNA Complex-Adjuvanted Influenza A Virus Vaccination Induces Robust Cross-Protective Immunity
Authors: Hong David K. , Chang Stella , Botham Crystal M. , Giffon Thierry D. , Fairman Jeffery , Lewis David B.
Published: October 2010

Influenza A virus is a negative-strand segmented RNA virus in which antigenically distinct viral subtypes are defined by the hemagglutinin (HA) and neuraminidase (NA) major viral surface proteins. An ideal inactivated vaccine for influenza A virus would induce not only highly robust strain-specific humoral and T-cell immune responses but also cross-protective immunity in which an immune response to antigens from a particular viral subtype (e.g., H3N2) would protect against other viral subtypes (e.g., H1N1). Cross-protective immunity would help limit outbreaks from newly emerging antigenically novel strains. Here, we show in mice that the addition of cationic lipid/noncoding DNA complexes (CLDC) as adjuvant to whole inactivated influenza A virus vaccine induces significantly more robust adaptive immune responses both in quantity and quality than aluminum hydroxide (alum), which is currently the most widely used adjuvant in clinical human vaccination. CLDC-adjuvanted vaccine induced higher total influenza virus-specific IgG, particularly for the IgG2a/c subclass. Higher levels of multicytokine-producing influenza virus-specific CD4 and CD8 T cells were induced by CLDC-adjuvanted vaccine than with alum-adjuvanted vaccine. Importantly, CLDC-adjuvanted vaccine provided significant cross-protection from either a sublethal or lethal influenza A viral challenge with a different subtype than that used for vaccination. This superior cross-protection afforded by the CLDC adjuvant required CD8 T-cell recognition of viral peptides presented by classical major histocompatibility complex class I proteins. Together, these results suggest that CLDC has particular promise for vaccine strategies in which T cells play an important role and may offer new opportunities for more effective control of human influenza epidemics and pandemics by inactivated influenza virus vaccine.
Interferon-Induced Cell Membrane Proteins, IFITM3 and Tetherin, Inhibit Vesicular Stomatitis Virus Infection via Distinct Mechanisms
Authors: Weidner Jessica M. , Jiang Dong , Pan Xiao-Ben , Chang Jinhong , Block Timothy M. , Guo Ju-Tao
Published: October 2010

Tetherin and IFITM3 are recently identified interferon-induced cellular proteins that restrict infections by retroviruses and filoviruses and of influenza virus and flaviviruses, respectively. In our efforts to further explore their antiviral activities against other viruses and determine their antiviral mechanisms, we found that the two antiviral proteins potently inhibit the infection of vesicular stomatitis virus (VSV), a prototype member of the
Rhabdoviridae
family. Taking advantage of this well-studied virus infection system, we show that although both tetherin and IFITM3 are plasma membrane proteins, tetherin inhibits virion particle release from infected cells, while IFITM3 disrupts an early event after endocytosis of virion particles but before primary transcription of incoming viral genomes. Furthermore, we demonstrate that both the N-terminal 21 amino acid residues and C-terminal transmembrane region of IFITM3 are required for its antiviral activity. Collectively, our work sheds light on the mechanisms by which tetherin and IFITM3 restrict infection with rhabdoviruses and possibly other pathogenic viruses.
Microevolution of Canine Influenza Virus in Shelters and Its Molecular Epidemiology in the United States
Authors: Hayward Jessica J. , Dubovi Edward J. , Scarlett Janet M. , Janeczko Stephanie , Holmes Edward C. , Parrish Colin R.
Published: October 2010

Canine influenza virus (CIV) emerged around 2000 when an equine influenza virus (EIV) was transmitted to dogs in Florida. After 2003, the canine virus was carried by infected greyhounds to various parts of the United States and then became established in several large animal shelters, where it has continued to circulate. To better understand the evolution of CIV since its emergence, and particularly its microevolution in spatially restricted populations, we examined multiple gene segments of CIV from dogs resident in two large animal shelters in New York City during the period 2006 to 2009. In particular, we focused on viruses circulating in the two shelters in 2008 and 2009, which we found shared a common ancestor. While viruses in each shelter were generally monophyletic, we observed some gene flow between them. These shelter sequences were compared to earlier CIV isolates. The shelter viruses differed in 1 to 6 amino acids in each gene segment compared to viruses isolated in Florida between 2003 and 2005 and in Colorado in 2006 and 2008. A comparison of the sequences of equine and canine viruses revealed amino acid replacements that distinguished the viruses from the two hosts, but no clear evidence of positive selection indicative of host adaptation was detected, suggesting that any host range adaptation in CIV occurred early in the emergence of this virus or even before it transferred to dogs.
Cytoplasmic Poly(A) Binding Proteins Regulate Telomerase Activity and Cell Growth in Human Papillomavirus Type 16 E6-Expressing Keratinocytes
Authors: Katzenellenbogen Rachel A. , Vliet-Gregg Portia , Xu Mei , Galloway Denise A.
Published: October 2010

The high-risk human papillomavirus (HPV) E6 and E7 oncoproteins are critical to the immortalization of keratinocytes. HPV type 16 (HPV16) E6 interacts with endogenous proteins to activate hTERT, the catalytic subunit of telomerase, thus avoiding cellular senescence signals. NFX1-123, the longer splice variant of NFX1, interacts with HPV16 E6, as well as cytoplasmic poly(A) binding proteins 1 and 4 (PABPC1 and PABPC4). HPV16 E6 affects hTERT expression posttranscriptionally through NFX1-123, as NFX1-123 interacts with hTERT mRNA and stabilizes it, leading to greater telomerase activity. The PAM2 motif of NFX1-123, with which it binds PABPCs, is required for the posttranscriptional regulation of hTERT by HPV16 E6 and NFX1-123. There is increasing evidence that RNA and DNA viruses utilize RNA-processing proteins, and specifically PABPCs, in the normal virus life cycle, and there is also evidence that RNA-processing proteins are perturbed in cancers. Here, we show that PABPCs are critical in hTERT regulation by HPV16 E6. Although the amount and cellular localization of PABPCs were largely unchanged in cervical cancer cell lines with or without HPV16 and in human foreskin keratinocytes (HFKs) with or without HPV16 E6, knockdown of PABPCs decreased hTERT mRNA and telomerase activity and overexpression of PABPC4 increased these in HPV16 E6-expressing HFKs. In contrast, knockdown of PABPCs in C33A cells had no effect on hTERT mRNA or telomerase activity. Additionally, overexpression of PABPC4 and hTERT led to greater growth of cultured HPV16 E6-expressing HFKs. This is the first evidence that PABPCs have a targeted role in hTERT regulation leading to a growth advantage in cells expressing HPV16 E6.
The Matrix Protein of Vesicular Stomatitis Virus Binds Dynamin for Efficient Viral Assembly
Authors: Raux Hélène , Obiang Linda , Richard Nicolas , Harper Francis , Blondel Danielle , Gaudin Yves
Published: October 2010

Matrix proteins (M) direct the process of assembly and budding of viruses belonging to the
Mononegavirales
order. Using the two-hybrid system, the amino-terminal part of vesicular stomatitis virus (VSV) M was shown to interact with dynamin pleckstrin homology domain. This interaction was confirmed by coimmunoprecipitation of both proteins in cells transfected by a plasmid encoding a c-myc-tagged dynamin and infected by VSV. A role for dynamin in the viral cycle (in addition to its role in virion endocytosis) was suggested by the fact that a late stage of the viral cycle was sensitive to dynasore. By alanine scanning, we identified a single mutation of M protein that abolished this interaction and reduced virus yield. The adaptation of mutant virus (M.L4A) occurred rapidly, allowing the isolation of revertants, among which the M protein, despite having an amino acid sequence distinct from that of the wild type, recovered a significant level of interaction with dynamin. This proved that the mutant phenotype was due to the loss of interaction between M and dynamin. The infectious cycle of the mutant virus M.L4A was blocked at a late stage, resulting in a quasi-absence of bullet-shaped viruses in the process of budding at the cell membrane. This was associated with an accumulation of nucleocapsids at the periphery of the cell and a different pattern of VSV glycoprotein localization. Finally, we showed that M-dynamin interaction affects clathrin-dependent endocytosis. Our study suggests that hijacking the endocytic pathway might be an important feature for enveloped virus assembly and budding at the plasma membrane.
Identification of Specific Determinants of Human APOBEC3F, APOBEC3C, and APOBEC3DE and African Green Monkey APOBEC3F That Interact with HIV-1 Vif
Authors: Smith Jessica L. , Pathak Vinay K.
Published: October 2010

Human APOBEC3F (hA3F) and human APOBEC3G (hA3G) are potent anti-human immunodeficiency virus (anti-HIV) host factors that suppress viral replication by hypermutating the viral genome, inhibiting reverse transcription, and hindering integration. To overcome hA3F and hA3G, HIV-1 encodes Vif, which binds and targets these host proteins for proteasomal degradation. Previously, we reported that the hA3F-Vif interactions that lead to hA3F degradation are located in the region comprising amino acids 283 to 300. We have now performed mutational analysis of this region and found that the
289
EFLARH
294
amino acids contribute to hA3F-Vif binding and are critical for A3F's sensitivity to Vif. Mutants in which E289 is mutated significantly increase hA3F's ability to inhibit viral infectivity in the presence of Vif, and coimmunoprecipitation assays show that binding of Vif to the E289K mutant is decreased. We examined the role of the EFLARH sequence in other A3 proteins, including human A3C (hA3C), human A3DE (hA3DE), African green monkey A3F (agmA3F), and rhesus macaque A3F (rhA3F). hA3C, hA3DE, and agmA3F were all susceptible to degradation induced by HIV-1 Vif, while rhA3F was not. Mutagenesis of the glutamate in the EFLARH sites of hA3C, hA3DE, and agmA3F decreases the susceptibilities of these proteins to Vif-induced degradation. Together, these results indicate that the EFLARH region in hA3F, hA3C, hA3DE, and agmA3F interacts with HIV-1 Vif and that this interaction plays a role in the Vif-mediated proteasomal degradation of these A3 proteins. These studies identify a conserved region in 3 of 7 human A3 proteins that is critical for degradation mediated by HIV-1 Vif and provide structural insights into the hA3F-Vif interactions that could facilitate the development of a novel class of anti-HIV agents.
The Nucleotides on the Stem-Loop RNA Structure in the Junction Region of the Hepatitis E Virus Genome Are Critical for Virus Replication
Authors: Cao Dianjun , Huang Yao-Wei , Meng Xiang-Jin
Published: October 2010

The roles of conserved nucleotides on the stem-loop (SL) structure in the intergenic region of the hepatitis E virus (HEV) genome in virus replication were determined by using Huh7 cells transfected with HEV SL mutant replicons containing reporter genes. One or two nucleotide mutations of the AGA motif on the loop significantly reduced HEV replication, and three or more nucleotide mutations on the loop abolished HEV replication. Mutations on the stem and of the subgenome start sequence also significantly inhibited HEV replication. The results indicated that both the sequence and the SL structure in the junction region play important roles in HEV replication.
Physical Interaction between the Herpes Simplex Virus Type 1 Exonuclease, UL12, and the DNA Double-Strand Break-Sensing MRN Complex
Authors: Balasubramanian Nandakumar , Bai Ping , Buchek Gregory , Korza George , Weller Sandra K.
Published: October 2010

The herpes simplex virus type 1 (HSV-1) alkaline nuclease, encoded by the UL12 gene, plays an important role in HSV-1 replication, as a UL12 null mutant displays a severe growth defect. The HSV-1 alkaline exonuclease UL12 interacts with the viral single-stranded DNA binding protein ICP8 and promotes strand exchange
in vitro
in conjunction with ICP8. We proposed that UL12 and ICP8 form a two-subunit recombinase reminiscent of the phage lambda Red α/β recombination system and that the viral and cellular recombinases contribute to viral genome replication through a homologous recombination-dependent DNA replication mechanism. To test this hypothesis, we identified cellular interaction partners of UL12 by using coimmunoprecipitation. We report for the first time a specific interaction between UL12 and components of the cellular MRN complex, an important factor in the ATM-mediated homologous recombination repair (HRR) pathway. This interaction is detected early during infection and does not require viral DNA or other viral or cellular proteins. The region of UL12 responsible for the interaction has been mapped to the first 125 residues, and coimmunoprecipitation can be abolished by deletion of residues 100 to 126. These observations support the hypothesis that cellular and viral recombination factors work together to promote efficient HSV-1 growth.
Suppression of Innate Immune Pathology by Regulatory T Cells during Influenza A Virus Infection of Immunodeficient Mice
Authors: Antunes Inês , Kassiotis George
Published: October 2010

The viral infection of higher vertebrates elicits potent innate and adaptive host immunity. However, an excessive or inappropriate immune response also may lead to host pathology that often is more severe than the direct effects of viral replication. Therefore, several mechanisms exist that regulate the magnitude and class of the immune response. Here, we have examined the potential involvement of regulatory T (Treg) cells in limiting pathology induced by influenza A virus (IAV) infection. Using lymphocyte-deficient mice as hosts, we showed that Treg cell reconstitution resulted in a significant delay in weight loss and prolonged survival following infection. The adoptively transferred Treg cells did not affect the high rate of IAV replication in the lungs of lymphocyte-deficient hosts, and therefore their disease-ameliorating effect was mediated through the suppression of innate immune pathology. Mechanistically, Treg cells reduced the accumulation and altered the distribution of monocytes/macrophages in the lungs of IAV-infected hosts. This reduction in lung monocytosis was associated with a specific delay in monocyte chemotactic protein-2 (MCP-2) induction in the infected lungs. Nevertheless, Treg cells failed to prevent the eventual development of severe disease in lymphocyte-deficient hosts, which likely was caused by the ongoing IAV replication. Indeed, using T-cell-deficient mice, which mounted a T-cell-independent B cell response to IAV, we further showed that the combination of virus-neutralizing antibodies and transferred Treg cells led to the complete prevention of clinical disease following IAV infection. Taken together, these results suggested that innate immune pathology and virus-induced pathology are the two main contributors to pathogenesis during IAV infection.
Cyclin T1/CDK9 Interacts with Influenza A Virus Polymerase and Facilitates Its Association with Cellular RNA Polymerase II
Authors: Zhang Junjie , Li Gang , Ye Xin
Published: October 2010

Influenza virus RNA-dependent RNA polymerase scavenges the 5′ cap from host pre-mRNA to prime viral transcription initiation. It is also well established that viral RNA-dependent RNA polymerase (vRNP) associates with cellular RNA polymerase II (Pol II), on which viral replication depends. Here we report that cyclin T1/CDK9 can interact with influenza virus polymerase and facilitate its association with cellular Pol II. The immunodepletion of cyclin T1/CDK9 totally abolished the association of vRNP with the C-terminal domain (CTD) Ser-2-phosphorylated form of RNA polymerase II. Further studies showed that overexpression of cyclin T1/CDK9 increased the transcription activity of vRNP, while knockdown of cyclin T1/CDK9 impaired viral replication. Our results suggest that cyclin T1/CDK9 serves as an adapter to mediate the interaction of vRNP and RNA Pol II and promote viral transcription.
Common Inbred Strains of the Laboratory Mouse That Are Susceptible to Infection by Mouse Xenotropic Gammaretroviruses and the Human-Derived Retrovirus XMRV
Authors: Baliji Surendranath , Liu Qingping , Kozak Christine A.
Published: October 2010

Laboratory mouse strains carry endogenous copies of the xenotropic mouse leukemia viruses (X-MLVs), named for their inability to infect cells of the laboratory mouse. This resistance to exogenous infection is due to a nonpermissive variant of the XPR1 gammaretrovirus receptor, a resistance that also limitsin vivoexpression of germ line X-MLV proviruses capable of producing infectious virus. Because laboratory mice vary widely in their proviral contents and in their virus expression patterns, we screened inbred strains for sequence and functional variants of the XPR1 receptor. We also typed inbred strains and wild mouse species for an endogenous provirus,Bxv1, that is capable of producing infectious X-MLV and that also contributes to the generation of pathogenic recombinant MLVs. We identified the activeBxv1provirus in many common inbred strains and in some JapaneseMus molossinusmice but in none of the other wild mouse species that carry X-MLVs. Our screening forXpr1variants identified the permissiveXpr1sxvallele in 7 strains of laboratory mice, including aBxv1-positive strain, F/St, which is characterized by lifelong X-MLV viremia. Cells from three strains carryingXpr1sxv, namely, SWR, SJL, and SIM.R, were shown to be infectable by X-MLV and XMRV; these strains carry different alleles atFv1and vary in their sensitivities to specific X/P-MLV isolates and XMRV. Several strains withXpr1sxvlack the activeBxv1provirus or other endogenous X-MLVs and may provide a useful model system to evaluate thein vivospread of these gammaretroviruses and their disease potential in their natural host.
The C-Terminal End of Parainfluenza Virus 5 NP Protein Is Important for Virus-Like Particle Production and M-NP Protein Interaction
Authors: Schmitt Phuong Tieu , Ray Greeshma , Schmitt Anthony P.
Published: October 2010

Enveloped virus particles are formed by budding from infected-cell membranes. For paramyxoviruses, viral matrix (M) proteins are key drivers of virus assembly and budding. However, other paramyxovirus proteins, including glycoproteins, nucleocapsid (NP or N) proteins, and C proteins, are also important for particle formation in some cases. To investigate the role of NP protein in parainfluenza virus 5 (PIV5) particle formation, NP protein truncation and substitution mutants were analyzed. Alterations near the C-terminal end of NP protein completely disrupted its virus-like particle (VLP) production function and significantly impaired M-NP protein interaction. Recombinant viruses with altered NP proteins were generated, and these viruses acquired second-site mutations. Recombinant viruses propagated in Vero cells acquired mutations that mainly affected components of the viral polymerase, while recombinant viruses propagated in MDBK cells acquired mutations that mainly affected the viral M protein. Two of the Vero-propagated viruses acquired the same mutation, V/P(S157F), found previously to be responsible for elevated viral gene expression induced by a well-characterized variant of PIV5, P/V-CPI
−
. Vero-propagated viruses caused elevated viral protein synthesis and spread rapidly through infected monolayers by direct cell-cell fusion, bypassing the need to bud infectious virions. Both Vero- and MDBK-propagated viruses exhibited infectivity defects and altered polypeptide composition, consistent with poor incorporation of viral ribonucleoprotein complexes (RNPs) into budding virions. Second-site mutations affecting M protein restored interaction with altered NP proteins in some cases and improved VLP production. These results suggest that multiple avenues are available to paramyxoviruses for overcoming defects in M-NP protein interaction.
International trade versus public health during the FCTC negotiations, 1999-2003
Authors: Mamudu Hadii M , Hammond Ross , Glantz Stanton A
Published: October 2010

Objective

To examine why the Framework Convention on Tobacco Control did not include an explicit trade provision and delineate the central arguments in the debate over trade provision during the negotiations.

Methods

Triangulate interviews with participants in the FCTC negotiations, the FCTC negotiations documents, and tobacco industry documents.

Results

An explicit FCTC trade provision on relation between international trade and public health became a contentious issue during the negotiations. As a result, two conflicting positions, health-over-trade and opposition to health-over-trade emerged. Opposition to explicit trade language giving health priority was by both tobacco industry and countries that generally supported strong FCTC provisions because of concerns over ‘disguised protectionism’ and setting a precedent whereby governments could forfeit their obligations under pre-existing treaties. Owing to lack of consensus among political actors involved in the negotiations, a compromise position eliminating any mention of trade emerged, which was predicated on belief among some in the public health community that public health would prevail in future trade versus health conflicts.

Conclusion

The absence of an explicit FCTC trade provision was due to a political compromise rather than the impact of international trade agreements and decisions on public health and lack of consensus among health advocates. This failure to include an explicit trade provision in the FCTC suggests that the public health community should become more involved in trade and health issues at all levels of governance and press the FCTC Conference of the Parties for clarification of this critical issue.
The role of parents, friends and teachers in adolescents' cigarette smoking and tombak dipping in Sudan
Authors: El-Amin Salma El-Tayeb , Nwaru Bright I , Ginawi Ibrahim , Pisani Paola , Hakama Matti
Published: October 2010

Objective

To assess the influence of smoking and tombak (local smokeless tobacco) dipping by parents, teachers and friends on cigarette smoking and tombak dipping by school-going Sudanese adolescents.

Methods

This was a school-based cross-sectional survey was conducted in 2005–2006. Logistic regression was used for the analysis. A total of 4277 Sudanese school-going adolescents (aged 11–17 years) from 23 schools who completed an anonymous self-administered questionnaire on the use of tobacco products. Main outcome measures were self-reported tobacco use during the previous month defined current tobacco use. Ever smoking, tombak dipping and other tobacco products were also considered as outcomes.

Results

After adjusting for sex, age and school grade, adolescents' smoking habits were strongly associated with the habit in their parents and friends and, more weakly, with tombak dipping by teachers. When adjusted for each other, the association with smoking in friends was unaffected and remained significant (prevalence OR (POR) of having ever smoked was 1.94, 95% CI 1.64 to 2.29; OR of being current smoker was 3.77, 95% CI 2.80 to 5.07). Tobacco smoking in friends was positively associated with adolescents ever tombak dipping (POR 1.81, 95% CI 1.41 to 2.33) and current dipping (OR 3.33, 95% CI 2.20 to 5.05). The association with parental habits was reduced but still significantly elevated. Tombak dipping by teachers was only associated with adolescents ever tobacco smoking.

Conclusions

Tobacco use by parents, teachers and friends was associated with adolescents' tobacco habits. The influence of friends was the strongest. In developing programmes against adolescents' tobacco habits, there is need to target the influence of these ‘significant others’. Sudan needs to develop and implement comprehensive anti-smoking and anti-tombak dipping legislation to reduce the growing prevalence of such habits.
Faunal assemblages from the upper Horseshoe Canyon Formation, an early Maastrichtian cool-climate assemblage from Alberta, with special reference to theAlbertosaurus sarcophagusbonebedThis article is one of a series of papers published in this Special Issue on the themeAlbertosaurus.
Authors: Larson Derek W. , Brinkman Donald B. , Bell Phil R.
Published: October 2010

The faunal assemblage from the early Maastrichtian portion of the Horseshoe Canyon Formation is described on the basis of four new vertebrate microfossil localities and remains from the Albertosaurus bonebed. All of the localities sampled were deposited during a cool, dry climate at a palaeolatitude of ∼58°N. Thus, these assemblages provide insight into a northern cool-climate assemblage in the early Maastrichtian of western North America. This fauna is characterized by the presence of taxa with more northern affinities, such as Holostean A, champsosaurs, Troodon , and toothed birds. Warm-climate taxa, such as crocodylians, large and diverse turtles, and albanerpetontids are notable in their absence. The Albertosaurus bonebed locality at the top of unit 4 of the Horseshoe Canyon Formation was deposited during the initial stages of a trend to a warmer and wetter climate that is represented in unit 5. The bonebed shares many taxa with the underlying vertebrate microfossil localities. However, a notable difference is the presence of Atrociraptor marshalli from the Albertosaurus bonebed but not the other localities in the upper Horseshoe Canyon Formation. The presence of Atrociraptor may be attributable to this change in climate rather than local ecological conditions. Also, the assemblages are different in the paucity of fish remains in the bonebed, and the relative rarity of shed hadrosaur teeth. The low abundance of aquatic taxa and rarity of shed teeth of hadrosaurs indicate that the locality is largely autochthonous, with little material being transported into the site.
Palaeopathological changes in a population of Albertosaurus sarcophagus from the Upper Cretaceous Horseshoe Canyon Formation of Alberta, CanadaThis article is one of a series of papers published in this Special Issue on the theme Albertosaurus.
Authors: Bell Phil R.
Published: October 2010

Over the past decade, excavations of a monodominant theropod bonebed from the lower Maastrichtian beds of the Horseshoe Canyon Formation have recovered a minimum number of 26 individuals of the tyrannosaur, Albertosaurus sarcophagus . Examination of skeletal elements from the bonebed revealed a small number of abnormalities from at least two individuals. These include bony spurs (enthesophytes) of unknown origin on three pedal phalanges. Well-healed fracture calluses are present on two rib shafts and a gastralia element. The left dentary of one adult preserves both healed and unhealed parallel bite marks and a perforative lesion attributable to a partially healed, mechanically induced puncture wound. Unfortunately, the limited range in the types and frequencies of pathological changes provides only little information on the distribution of such phenomena but may be suggestive of the overall “health” of the population.
A new articulated freshwater fish (Clupeomorpha, Ellimmichthyiformes) from the Horseshoe Canyon Formation, Maastrichtian, of Alberta, CanadaThis article is one of a series of papers published in this Special Issue on the themeAlbertosaurus.
Authors: Newbrey Michael G. , Murray Alison M. , Brinkman Donald B. , Wilson Mark V. H. , Neuman Andrew G.
Published: October 2010

Horseshoeichthys armaserratus , gen. et sp. nov., (Clupeomorpha: Ellimmichthyiformes: Sorbinichthyidae) is described from the Horseshoe Canyon Formation (Maastrichtian), Albertosaurus bonebed locality, Alberta, Canada. Horseshoeichthys armaserratus is classified as an ellimmichthyiform based on the following characters: the presence of a sixth infraorbital with a sensory canal that leads to the fifth infraorbital, absence of a supraorbital bone, subrectangular predorsal scutes, parietals in contact with each other at the midline, and two supramaxillae. The specimen is classified in the Sorbinichthyidae Family as it has abdominal ribs articulating in pits on the centra, posterior spines on predorsal scutes, and absence of a median spine on predorsal scutes. A new genus and species is proposed based on the presence of (anteriorly) Y-shaped mesethmoid, supraorbital, subrectangular predorsal scutes with coarse, rounded serrae on the posterior margin and a large anterior projection, scales with serrae on the circuli, and two postcleithra. This specimen represents the first freshwater ellimmichthyiform from the Upper Cretaceous of North America and the highest paleolatitude (59°N) occurrence known for the family. Furthermore, the dentary and centra have distinctive morphologies that are matched by specimens in microvertebrate localities from three underlying formations, including the Milk River Formation (Santonian), which indicates at least a 14 million year history for this lineage.
Reactions of toluquinone – cyclopentadiene Diels –Alder epoxide adducts with nucleophiles under heterogeneous conditions
Authors: von Richthofen Andreas A. , Cardoso Filho José E. P. , Marzorati Liliana , Zukerman-Schpector Julio , Tiekink Edward R.T. , Di Vitta Claudio
Published: October 2010

Toluquinone–cyclopentadiene Diels–Alder epoxide adducts react with sulfur and oxygen nucleophiles under heterogeneous conditions, leading to products resulting from the epoxide ring opening and from skeletal rearrangement, respectively. Pyrolysis of the sulfanyl adducts gave the new 3-sulfanyltoluquinones (1).
One-pot synthesis of β-diketimine ligands
Authors: El-Zoghbi Ibrahim , Ased Aysha , Oguadinma Paul O. , Tchirioua Ekou , Schaper Frank
Published: October 2010

Symmetric N,N′-dialkyl-2-amino-4-imino-pent-2-enes (nacnacRH) can be prepared in high yields in a simple one-pot reaction from acetylacetone and 2 equiv. of amine. Optimized conditions require the azeotropic removal of water, use of a minimum amount of solvent, and of 1 equiv. of acid. Either para-toluenesulfonic acid, hydrochloric acid, or a mixture of both can be employed, with the latter being most advantageous. Symmetric nacnacRH are thus obtained in higher than 95% purity and with 65% yield for R = Me and 80%–95% yields for R = n-Pr, i-Pr, i-Bu, Bn, Cy, and (+)-CH(Me)Ph.
A convenient route to distannanes, oligostannanes, and polystannanes
Authors: Khan Aman , Gossage Robert A. , Foucher Daniel A.
Published: October 2010

The quantitative conversion of the tertiary stannane (n-Bu)3SnH (2) into (n-Bu)6Sn2 (4) was achieved by heating the neat hydride material under low pressure or under closed inert atmosphere conditions. A 31% conversion of Ph3SnH (3) to Ph6Sn2 (5) was also observed under low pressure; however, under closed inert atmosphere conditions afforded Ph4Sn (6) as the major product. A mixed distannane, (n-Bu)3SnSnPh3 (7), can also be prepared in good yield utilizing an equal molar ratio of 2 and 3 and the same reaction conditions used to prepare 4. This solvent-free, catalyst-free route to distannanes was extended to a secondary stannane, (n-Bu)2SnH2 (8), which yielded evidence (NMR) for hydride terminated distannane H(n-Bu)2SnSn(n-Bu)2H (9), the polystannane [(n-Bu)2Sn]n (10), and various cyclic stannanes [(n-Bu)2Sn]n=5,6 (11, 12). Further evidence for 10 was afforded by gel permeation chromatography (GPC) where a broad, moderate molecular weight, but highly dispersed polymer, was obtained (Mw = 1.8 × 104 Da, polydispersity index (PDI) = 6.9) and a characteristic UV–vis absorbance (λmax) of ≈370 nm observed.
PHASE STRUCTURE OF A FOUR- AND EIGHT-FERMION INTERACTION MODEL AT FINITE TEMPERATURE AND CHEMICAL POTENTIAL IN ARBITRARY DIMENSIONS
Authors: HAYASHI MASAKO , INAGAKI TOMOHIRO , SAKAMOTO WATARU
Published: October 2010

The phase structure of a four- and eight-fermion interaction model is investigated at finite temperature and chemical potential in arbitrary space–time dimensions, 2 ≤ D < 4. The effective potential and the gap equation are calculated in the leading order of the 1/N expansion. If the first order phase transition takes place, the phase boundary dividing the symmetric and the broken phase is modified by the eight-fermion interaction.
THE GENERALIZED BREIT OPERATOR OF A LONG-RANGE TYPE IN THE FRAMEWORK OF THE SECOND-ORDER EFFECTS OF QUANTUM ELECTRODYNAMICS
Authors: YU. LAZUR V. , MYHALYNA S. I. , REITY O. K.
Published: October 2010

The problem of interaction of two quasimolecular electrons located at an arbitrary distance from each other and near different atoms (nuclei) is solved. The interaction is considered as a second-order effect of quantum electrodynamics in the coordinate representation. It is shown that a consistent account for the natural condition of the interaction symmetry with respect to both electrons leads to an additional contribution to the relativistic interaction of the two quasimolecular electrons compared with both the standard Breit operator and the generalized Breit operator known previously. The generalized Breit–Pauli operator and the operator of electric dipole–dipole interaction of two quasimolecular electrons located at an arbitrary distance from each other are obtained. Modern methods of accounting for the relativistic and correlative effects in the problem of ion–atom interactions are discussed.
EFFECT OF EXTERNAL MAGNETIC FIELD AND STUDY OF DENSITY OF STATES OF SUPERCONDUCTIVITY IN RNi2B2C
Authors: SAHOO B. K. , PANDA B. N.
Published: October 2010

A microscopic theoretical study of external magnetic field effect on superconductivity and density of states (DOS) in rare earth nickel borocarbide superconductors ( RNi 2 B 2 C ) is reported here. A Hamiltonian model is used to describe the system to which a BCS-type Cooper pairing mechanism is added. The expression for SC order parameter (z) is calculated by the Green's function technique of D. N. Zubarev. The variation of superconducting gap with temperature is investigated at different external magnetic fields. The phase diagram between temperature (θ) and critical magnetic field (bc) agrees with experimental observations. The gap edges in the DOS appear at ±2z in the absence of external magnetic field. On the application of external magnetic field in the DOS, the gap edges appear at ±(z - b) which resembles the tunneling conductance of STM experiment.
ELECTRICAL AND MAGNETIC PROPERTIES OF LOW-TEMPERATURE SINTERED xTiO2+(1-x)Ni0.2Cu0.2Zn0.62O(Fe2O3)0.98 CERAMICS
Authors: SU LI-NA , LIU PENG , HE YING , MU CHUN-HONG , ZHOU JIAN-PING , CAO LEI , LIU CHENG , ZHANG HUAI-WU , YAO GUO-GUANG
Published: October 2010

For the purpose of multi-layer chip electromagnetic interference (EMI) filters, a series of x TiO 2 + (1 - x) Ni 0.2 Cu 0.2 Zn 0.62 O ( Fe 2 O 3)0.98 ( NiCuZn ferrite) (0 ≤ x ≤ 60 wt .%) composite ceramics were primarily prepared by a solid-state reaction method. With addition of 3 wt.% Bi 2 O 3, all the ceramics can be sintered at 900°C. The effects of composition x on the sintering behaviors, phase compositions and electromagnetic properties of TiO 2+ NiCuZn ferrite ceramics were investigated. The X-ray diffraction (XRD) results showed that the ceramics were composed of NiCuZn , Fe 3 Ti 3 O 10 and TiO 2 phases. Scanning electron micrographs showed that 10 wt.% TiO 2 to 90 wt.% Ni 0.2 Cu 0.2 Zn 0.62 O ( Fe 2 O 3)0.98 ceramics had small grain size and high density. With an increase of TiO 2 content x, the value of εr decreased and the component with 10 wt.% TiO 2 had maximum relative dielectric constant. The permeability and the saturation magnetization decreased gradually with increasing TiO 2 content, and the permeability curve exhibited excellent stability of frequency. The composite materials with 10 wt.% TiO 2 showed typical magnetic hysteresis of the magnetic materials. For the specimens with 10 wt.% TiO 2 to 90 wt.% Ni 0.2 Cu 0.2 Zn 0.62 O ( Fe 2 O 3)0.98, the good dielectric (εr = 50) and magnetic properties (μ = 30, tan δ| 10 MHz = 0.13) have been obtained at 900°C.
THERMAL STABILITY OF ENERGY-EMISSION FROM CdTe NANOCRYSTALS EMBEDDED IN SiO2 THIN FILMS
Authors: LEVICHEV S. , CHAHBOUN A. , ROLO A. G. , CONDE O. , GOMES M. J. M.
Published: October 2010

CdTe -doped SiO 2 thin films were produced by RF magnetron co-sputtering technique. Presence of CdTe nanocrystals inside the silica matrix was confirmed by Raman spectroscopy and grazing incidence X-ray diffraction. The samples demonstrate size dependent photoluminescence. Temperature dependent photoluminescence measurements were carried out in the temperature range 15–295 K and revealed energy-emission thermal stability. This feature can be usefully applied in a production of light-emitting diodes with wavelength stability in a wide temperature range.
DOPING AND TEMPERATURE DEPENDENCE OF SUPERFLUID DENSITY IN KINETIC ENERGY DRIVEN CUPRATE SUPERCONDUCTORS
Authors: HUANG ZHEYU , ZHAO HUAISONG , FENG SHIPING
Published: October 2010

Within the kinetic energy driven superconducting mechanism, the doping and temperature dependence of the superfluid density in cuprate superconductors is studied throughout the superconducting dome. It is shown that the superfluid density shows a crossover from the linear temperature dependence at low temperatures to a nonlinear one in the extremely low temperatures. In analogy to the dome-like shape of the doping dependent superconducting transition temperature, the maximal zero-temperature superfluid density occurs around the critical doping δ ≈ 0.195, and then decreases in both lower doped and higher doped regimes.
ON THE STRUCTURE OF THE KNEADING SPACE OF BIMODAL DEGREE ONE CIRCLE MAPS
Authors: ALSEDÀ LL. , FALCÓ A.
Published: October 2010

In this paper, we introduce an index space and two ⋆-like operators that can be used to describe bifurcations for parametrized families of degree one circle maps. Using these topological tools, we give a description of the kneading space, that is, the set of all dynamical combinatorial types for the class of all bimodal degree one circle maps considered as dynamical systems.