bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pathogenicity and Immunogenicity of a Mutant Strain of
Listeria monocytogenes
in the Chicken Infection Model
Authors: Yin Yuelan , Tian Debin , Jiao Hongmei , Zhang Chenju , Pan Zhiming , Zhang Xiaoming , Wang Xiaobo , Jiao Xinan 
Published: January 2011

ABSTRACT

Listeria monocytogenes
has been exploited as a vaccine carrier based upon its ability to induce a strong cell-mediated immune response. At present, the safety of live, attenuated
L. monocytogenes
vaccines in patients is being studied in clinical trials.
L. monocytogenes
is also an attractive vaccine vector for use in poultry; however, the pathogenicity and immunogenicity of this organism in poultry remain to be fully elucidated. In this study, we investigated the pathogenicity and immunogenicity of an
actA
- and
plcB
-deficient
L. monocytogenes
strain, yzuLM4Δ
actA
/
plcB
, and its wild-type parent strain, yzuLM4, in an avian infection model. The results showed that the wild-type strain could infect ISA brown chickens, causing serious tissue disruptions, including various degrees of degeneration, necrotic lesions, and inflammatory cell infiltration in the liver, spleen, heart, and kidney. However, the mutant strain showed reduced virulence in embryonated eggs compared with that of the parent strain (the 50% lethal dose [LD
50
] was 3 logs higher). The mutant strain also showed low virulence in chickens and was rapidly eliminated by the host. There were no obvious pathological changes in tissue sections, but the mutant strain still retained the ability to stimulate high levels of antibody against the protein listeriolysin O (LLO). Booster immunization with the mutant strain led to rapid bacterial clearance from the livers and spleens of chickens challenged by the intramuscular route or the oral route. Collectively, our data suggest that the wild-type serotype 1/2a
L. monocytogenes
strain can cause serious disease in chickens but the mutant strain with a deletion of the
actA
and
plcB
genes is less virulent but induces a strong immune response. This mutant strain of
L. monocytogenes
is therefore a promising candidate as a safe and effective vector for the delivery of heterologous antigens to prevent zoonosis and infectious disease in poultry.
Full Serotype- and Group-Specific NS1 Capture Enzyme-Linked Immunosorbent Assay for Rapid Differential Diagnosis of Dengue Virus Infection
Authors: Ding Xixia , Hu Dongmei , Chen Yue , Di Biao , Jin Jing , Pan Yuxian , Qiu Liwen , Wang Yadi , Wen Kun , Wang Ming , Che Xiaoyan 
Published: January 2011

ABSTRACT

Dengue virus (DENV), a member of the
Flavivirus
family, has four distinct serotypes (DENV serotype 1 [DENV1], DENV2, DENV3, and DENV4) that require differentiation for the effective prevention of morbid disease. Early and rapid differentiation between flaviviruses remains challenging. Full assays combining four individual, serotype-specific and one group-specific nonstructural protein 1 (NS1) antigen capture enzyme-linked immunosorbent assays (ELISAs) based on monoclonal antibodies (MAbs) against DENV NS1 were developed and validated. The sensitivities and specificities of the full NS1 ELISAs were evaluated with viral cultures and dengue acute-phase sera. Four serotype-specific NS1 ELISAs displayed high specificities for the detection and differentiation of appropriate serotypes. The group-specific NS1 ELISA was broadly reactive with the four dengue virus serotypes. None of the NS1 ELISAs displayed cross-reactivity with the other flaviviruses or samples from febrile patients with non-dengue virus infections. The full serotype- and group-specific MAb-based NS1 capture ELISAs may provide tools for the early detection and typing of dengue infection, which is preferable to reverse transcriptase PCR (RT-PCR) for the rapid differential diagnosis of dengue virus infection in the field.
Identification of Surrogates and Correlates of Protection in Protective Immunity againstMycobacterium bovisInfection Induced in Neonatal Calves by Vaccination withM. bovisBCG Pasteur andM. bovisBCG Danish
Authors: Hope J. C. , Thom M. L. , McAulay M. , Mead E. , Vordermeier H. M. , Clifford D. , Hewinson R. G. , Villarreal-Ramos B. 
Published: January 2011

ABSTRACTVaccination of neonatal calves withMycobacterium bovisbacillus Calmette-Guérin (BCG) induces a significant degree of protection against infection with virulentM. bovis, the causative agent of bovine tuberculosis (bTB). We compared two strains of BCG, Pasteur and Danish, in order to confirm that the current European human vaccine strain (BCG Danish) induced protective immunity in calves, and we assessed immune responses to determine correlates of protection that could assist future vaccine evaluation in cattle. Both vaccine strains induced antigen (purified protein derivate [PPD])-specific gamma interferon (IFN-γ) in whole-blood cultures. These responses were not significantly different for BCG Pasteur and BCG Danish and peaked at week 2 to 4 postvaccination. Vaccination with either BCG Danish or BCG Pasteur induced significant protection against bTB, with reductions in both lesion score and bacteriological burden evident in both groups of vaccinated calves compared with nonvaccinated control calves. Measurement of IFN-γ-expressing T lymphocytes postvaccination and postchallenge revealed both correlates and surrogates of protective efficacy. The frequency of central memory T lymphocytes present at 12 weeks postvaccination (at the time ofM. bovischallenge) correlated significantly with protection. Conversely, the number of IFN-γ-expressing effector T cells present afterM. bovischallenge was correlated with disease. These results demonstrate that vaccination of neonatal calves with either BCG Pasteur or BCG Danish induces protective immune responses against TB. In addition, we show that measurement of antigen-specific T lymphocyte populations may provide a reliable means for identifying protective vaccine candidates.
Human Bocavirus as the Cause of a Life-Threatening Infection
Authors: Uršič Tina , Steyer Andrej , Kopriva Silvester , Kalan Gorazd , Krivec Uroš , Petrovec Miroslav 
Published: January 2011

ABSTRACT
Human bocavirus is a recently described respiratory pathogen. A case of a life-threatening human bocavirus infection of a previously healthy pediatric patient is described. An initial clinical presentation of acute bronchiolitis developed into an extremely severe course of disease characterized by pneumothorax, pneumomediastinum, and acute respiratory failure with pronounced air-leak syndrome.
Rotavirus Replication Requires a Functional Proteasome for Effective Assembly of Viroplasms
Authors: Contin R. , Arnoldi F. , Mano M. , Burrone O. R. 
Published: January 2011

ABSTRACTThe ubiquitin-proteasome system has been shown to play an important role in the replication cycle of different viruses. In this study, we describe a strong impairment of rotavirus replication upon inhibition of proteasomal activity. The effect was evidenced at the level of accumulation of viral proteins, viral RNA, and yield of infective particles. Kinetic studies revealed that the early steps of the replicative cycle following attachment, entry, and uncoating were clearly more sensitive to proteasome inhibition. We ruled out a direct inhibition of the viral polymerase activities and stability of viral proteins and found that the crucial step that was impaired by blocking proteasome activity was the assembly of new viroplasms. This was demonstrated by using chemical inhibitors of proteasome and by gene silencing using small interfering RNAs (siRNAs) specific for different proteasomal subunits and for the ubiquitin precursor RPS27A. In addition, we show that the effect of proteasome inhibition on virus infection is not due to increased levels of beta interferon (IFN-β).
Hepatitis B Virus X Protein Enhances Cisplatin-Induced Hepatotoxicity via a Mechanism Involving Degradation of Mcl-1
Authors: Hu Liang , Chen Lei , Li Liang , Sun HanYong , Yang GuangZhen , Chang YanXin , Tu QianQian , Wu MengChao , Wang HongYang 
Published: January 2011

ABSTRACTHepatitis B virus X protein (HBx) is implicated in the pathogenesis of hepatitis B virus (HBV)-associated liver diseases. However, whether HBx has the ability to disturb the susceptibility of hepatocytes to common chemotherapeutic agents remains incompletely understood. Here we demonstrate that HBx enhances cisplatin-induced hepatotoxicity by a mechanism involving degradation of Mcl-1, an antiapoptotic member of the Bcl-2 family. Ectopic expression of HBx sensitized hepatocytes to cisplatin-induced apoptosis, which was accompanied by a marked downregulation of Mcl-1 but not of Bcl-2 or Bcl-xL. Overexpression of Mcl-1 prevented HBx-induced proapoptotic and proinflammatory effects during cisplatin treatment bothin vitroandin vivo. HBx-induced dysregulation of Mcl-1 resulted mainly from posttranslational degradation rather than transcription repression. Moreover, a caspase-3 inhibitor effectively abrogated HBx-enhanced Mcl-1 degradation and cell death. Importantly, antioxidants blocked activation of caspase-3 and acceleration of Mcl-1 loss, as well as cell death, in HBx-expressing hepatocytes upon cisplatin exposurein vitroandin vivo. Collectively, these data implicate oxidative stress-dependent caspase-3-mediated degradation of Mcl-1 as a mechanism contributing to HBx-mediated sensitization of cisplatin-induced hepatotoxicity. A combination of cisplatin and antioxidants might provide more advantage than cisplatin alone in the treatment of cancer patients with chronic HBV infection.
Regulation of the Human Papillomavirus Type 18 E6/E6AP Ubiquitin Ligase Complex by the HECT Domain-Containing Protein EDD
Authors: Tomaić Vjekoslav , Pim David , Thomas Miranda , Massimi Paola , Myers Michael P. , Banks Lawrence 
Published: January 2011

ABSTRACT
Human papillomavirus (HPV) E6 oncoproteins target many cellular proteins for ubiquitin-mediated proteasomal degradation. In the case of p53, this is mediated principally by the E6AP ubiquitin ligase. Several studies have reported that E6 can target certain of its substrates in an apparently E6AP-independent fashion and that several of these substrates vary in the degree to which they are degraded by E6 at different stages of malignancy. To more fully understand the regulation of the E6AP/E6 proteolytic targeting complex, we performed a mass spectroscopic analysis of HPV type 18 (HPV-18) E6 protein complexes and identified the HECT domain-containing ubiquitin ligase EDD as a new HPV-18 E6 binding partner. We show that EDD can interact independently with both E6 and E6AP. Furthermore, EDD appears to regulate E6AP expression levels independently of E6, and loss of EDD stimulates the proteolytic activity of the E6/E6AP complex. Conversely, higher levels of EDD expression protect a number of substrates from E6-induced degradation, partly as a consequence of lower levels of E6 and E6AP expression. Intriguingly, reduction in EDD expression levels in HPV-18-positive HeLa cells enhances cell resistance to apoptotic and growth arrest stimuli. These studies suggest that changes in the levels of EDD expression during different stages of the viral life cycle or during malignancy could have a profound effect upon the ability of E6 to target various substrates for proteolytic degradation and thereby directly influence the development of HPV-induced malignancy.
Recombinant Sendai Viruses Expressing Fusion Proteins with Two Furin Cleavage Sites Mimic the Syncytial and Receptor-Independent Infection Properties of Respiratory Syncytial Virus
Authors: Rawling Joanna , Cano Olga , Garcin Dominique , Kolakofsky Daniel , Melero José A. 
Published: January 2011

ABSTRACTCell entry by paramyxoviruses requires fusion between viral and cellular membranes. Paramyxovirus infection also gives rise to the formation of multinuclear, fused cells (syncytia). Both types of fusion are mediated by the viral fusion (F) protein, which requires proteolytic processing at a basic cleavage site in order to be active for fusion. In common with most paramyxoviruses, fusion mediated by Sendai virus F protein (FSeV) requires coexpression of the homologous attachment (hemagglutinin-neuraminidase [HN]) protein, which binds to cell surface sialic acid receptors. In contrast, respiratory syncytial virus fusion protein (FRSV) is capable of fusing membranes in the absence of the viral attachment (G) protein. Moreover, FRSVis unique among paramyxovirus fusion proteins since FRSVpossesses two multibasic cleavage sites, which are separated by an intervening region of 27 amino acids. We have previously shown that insertion of both FRSVcleavage sites in FSeVdecreases dependency on the HN attachment protein for syncytium formation in transfected cells. We now describe recombinant Sendai viruses (rSeV) that express mutant F proteins containing one or both FRSVcleavage sites. All cleavage-site mutant viruses displayed reduced thermostability, with double-cleavage-site mutants exhibiting a hyperfusogenic phenotype in infected cells. Furthermore, insertion of both FRSVcleavage sites in FSeVreduced dependency on the interaction of HN with sialic acid for infection, thus mimicking the unique ability of RSV to fuse and infect cells in the absence of a separate attachment protein.
Superparamagnetic Nanoparticle Capture of Prions for Amplification
Authors: Miller Michael B. , Supattapone Surachai 
Published: January 2011

ABSTRACT

Prion diseases are associated with the presence of PrP
Sc
, a disease-associated misfolded conformer of the prion protein. We report that superparamagnetic nanoparticles bind PrP
Sc
molecules efficiently and specifically, permitting magnetic separation of prions from a sample mixture. Captured PrP
Sc
molecules retain the activity to seed protein misfolding cyclic amplification (PMCA) reactions, enabling the rapid concentration of dilute prions to improve detection. Furthermore, superparamagnetic nanoparticles clear contaminated solutions of PrP
Sc
. Our findings suggest that coupling magnetic nanoparticle capture with PMCA could accelerate and improve prion detection. Magnetic nanoparticles may also be useful for developing a nontoxic prion decontamination method for biologically derived products.
Histone Demethylase JMJD2A Regulates Kaposi's Sarcoma-Associated Herpesvirus Replication and Is Targeted by a Viral Transcriptional Factor
Authors: Chang Pei-Ching , Fitzgerald Latricia D. , Hsia Datsun A. , Izumiya Yoshihiro , Wu Chun-Yi , Hsieh Wen-Ping , Lin Su-Fang , Campbell Mel , Lam Kit S. , Luciw Paul A. , Tepper Clifford G. , Kung Hsing-Jien 
Published: January 2011

ABSTRACT

The switch between the latency and lytic cycles of Kaposi's sarcoma-associated herpesvirus (KSHV) is accompanied by specific alterations of histone codes. Recently, comprehensive analysis of histone modifications of KSHV showed the deposition of H3K27me3 across the KSHV genome with two specific regions occupied by the heterochromatin marker H3K9me3. Here, we show that knockdown of JMJD2A, an H3K9me3 demethylase, attenuates viral titers, whereas its overexpression increases KSHV reactivation. JMJD2A is localized in regions of latent viral chromosomes that are deficient in the H3K9me3 mark, indicating that JMJD2A may be responsible for the low level of this mark on viral chromatin. The presence of JMJD2A on the latent genome maintains H3K9 in unmethylated form and signals the readiness of specific sets of viral genes to be reactivated. The demethylase activity of JMJD2A is important for KSHV reactivation, because a demethylase-deficient mutant cannot restore the JMJD2A knockdown phenotype. Interestingly, we found that the KSHV encoded K-bZIP associated with JMJD2A, resulting in the inhibition of demethylase activity of JMJD2A both
in vivo
and
in vitro
. Inhibition of JMJD2A by K-bZIP is likely due to a physical interaction which blocks substrate accessibility. A consequence of such an inhibition is increasing global levels of H3K9me3 and gene silencing. Consistently, K-bZIP overexpression resulted in a repression of ∼80% of the ≥2-fold differentially regulated genes compared to results for the uninduced control cells. The consequences of K-bZIP targeting JMJD2A during viral replication will be discussed. To our knowledge, this is the first description of a viral product shown to be a potent inhibitor of a host cellular histone demethylase.
High oesophageal web formation in association with heterotopic gastric mucosa (the gastric inlet patch): a small case series
Authors: Ainley Eric J 
Published: January 2011

BackgroundUpper oesophageal webs or rings have rarely been reported in association with heterotopic gastric mucosa (HGM).ObjectiveTo describe the finding of oesophageal webs in association with HGM.DesignSmall case series.SettingPatients presenting with dysphagia to an open access hospital dysphagia clinic.PatientsSix cases were found.InterventionsSymptomatic improvement is demonstrated with oesophageal dilatation in symptomatic patients.Main outcome measurementsSymptomatic improvement.ResultsThe six cases which are described here demonstrate that a web or ring exactly matches the distribution of the heterotopic mucosa, can occur at both proximal and distal squamo-columnar junctions and the inlet patches may be multiple with multiple rings. A radiological double web sign is described.LimitationsA rare condition with a small number of patients.ConclusionsEffective treatment can be by oesophageal dilatation and acid suppression. The cause of web formation is thought to be due to heterotopic acid production and is analogous to the Schatzki ring.
CLASSES DE STEINITZ D'EXTENSIONS NON ABÉLIENNES À GROUPE DE GALOIS D'ORDRE 16 OU EXTRASPÉCIAL D'ORDRE 32 ET PROBLÈME DE PLONGEMENT
Authors: SBEITY FARAH , SODAÏGUI BOUCHAÏB 
Published: January 2011

Soient k un corps de nombres et Cl (k) son groupe des classes. Soit Γ un groupe non abélien d'ordre 16, ou un groupe extraspécial d'ordre 32. Soit Rm(k, Γ) le sous-ensemble de Cl (k) formé par les éléments qui sont réalisables par les classes de Steinitz d'extensions galoisiennes de k, modérément ramifiées et dont le groupe de Galois est isomorphe à Γ. Lorsque Γ est le groupe modulaire d'ordre 16, on suppose que k contienne une racine primitive 4ème de l'unité. Dans cet article on montre que Rm(k, Γ) est le groupe Cl (k) tout entier si le nombre des classes de k est impair. On étudie un problème de plongement en liaison avec les classes de Steinitz dans la perspective de l'étude des classes galoisiennes réalisables. On prouve que pour tout c ∈ Cl (k), il existe une extension quadratique de k, modérée, dont la classe de Steinitz est c, et qui est plongeable dans une extension galoisienne de k, modérée et à groupe de Galois isomorphe à Γ. Let k be a number field and Cl (k) its class group. Let Γ be a nonabelian group of order 16 or an extra-special group of order 32. Let Rm(k, Γ) be the subset of Cl (k) consisting of those classes which are realizable as Steinitz classes of tame Galois extensions of k with Galois group isomorphic to Γ. When Γ is the modular group of order 16, we assume that k contains a primitive 4th root of unity. In the present paper, we show that Rm(k, Γ) is the full group Cl (k) if the class number of k is odd. We study an embedding problem connected with Steinitz classes in the perspective of studying realizable Galois module classes. We prove that for all c∈ Cl (k), there exist a tame quadratic extension of k, with Steinitz class c, and which is embeddable in a tame Galois extension of k with Galois group isomorphic to Γ.
THE DEVELOPMENT AND STABILITY ANALYSIS OF A NONLINEAR GROWTH MODEL FOR MICROORGANISMS
Authors: LI YUHONG , MEN HONG , THOMSON GARETH , TIAN FANGBAO 
Published: January 2011

A nonlinear dynamic model of microbial growth is established based on the theories of the diffusion response of thermodynamics and the chemotactic response of biology. Except for the two traditional variables, i.e. the density of bacteria and the concentration of attractant, the pH value, a crucial influencing factor to the microbial growth, is also considered in this model. The pH effect on the microbial growth is taken as a Gaussian function G0e-(φ- φc)2/G1, where G0, G1 and φc are constants, φ represents the pH value and φc represents the critical pH value that best fits for microbial growth. To study the effects of the reproduction rate of the bacteria and the pH value on the stability of the system, three parameters a, G0 and G1 are studied in detail, where a denotes the reproduction rate of the bacteria, G0 denotes the impacting intensity of the pH value to microbial growth and G1 denotes the bacterial adaptability to the pH value. When the effect of the pH value of the solution which microorganisms live in is ignored in the governing equations of the model, the microbial system is more stable with larger a. When the effect of the bacterial chemotaxis is ignored, the microbial system is more stable with the larger G1 and more unstable with the larger G0 for φ0 > φc. However, the stability of the microbial system is almost unaffected by the variation G0 and G1 and it is always stable for φ0 < φc under the assumed conditions in this paper. In the whole system model, it is more unstable with larger G1 and more stable with larger G0 for φ0 < φc. The system is more stable with larger G1 and more unstable with larger G0 for φ0 > φc. However, the system is more unstable with larger a for φ0 < φc and the stability of the system is almost unaffected by a for φ0 > φc. The results obtained in this study provide a biophysical insight into the understanding of the growth and stability behavior of microorganisms.
Granite-related ore deposits: an introduction
Authors: Sial A. N. , Bettencourt Jorge S. , De Campos Cristina P. , Ferreira Valderez P. 
Published: January 2011

Abstract
A symposium on Mineralization Associated with Granitic Magmatism was held within the framework of the 33rd IGC in Oslo, Norway, in August 2008. While our initial idea was to bring together field, experimental, and theoretical studies in order to review and summarize the current ideas and recent progress on granite-related mineralization systems, we were caught by surprise realizing that participants were inclined to focus more on ore deposits related to granitic magmatism. This spontaneous shift from granites, the major intended focus of the symposium, to mineralization associated with them, spawned the idea for a special issue on this theme and ultimately to the nine papers assembled here, chosen from about 60 scientific contributions at the symposium. Around twenty oral presentations were given and forty posters were presented at the meeting; the 60 papers were grouped according to the current main granite-related ore systems, as follows; granite-pegmatite, skarn and greisen-veins, porphyry, orogenic gold, intrusion-related, epithermal and porphyry-related gold and base metal, iron oxide–copper–gold (IOCG), and special case studies.