Science.gov

Sample records for additional host factors

  1. [Host factors and viral factors in hepatitis C treatment].

    PubMed

    Sakamoto, Minoru; Enomoto, Nobuyuki

    2015-02-01

    In the interferon-based therapy for hepatitis C, host factors such as age, gender, liver fibrosis and steatosis are important as a therapeutic effect predictor, and viral factors such as HCV genotype, HCV viral load, HCV gene (IL28B, ITPA) are also important. In addition in genotype 1b, ISDR/IRRDR and core amino acid substitution are important. Also in the DAA treatment, viral factors are also important at the view of therapeutic effect and difficulty of acquisition of drug resistance mutation. In addition, the goal of treatment of hepatitis C are suppression of liver fibrosis progression and liver cancer and improvement of quality of life due to this (quality of life: QOL) and life prognosis, it is important to understand the host factors and HCV viral factors. PMID:25764672

  2. Host restriction factors for hepatitis C virus

    PubMed Central

    Zhou, Li-Ya; Zhang, Lei-Liang

    2016-01-01

    Host-hepatitis C virus (HCV) interactions have both informed fundamental concepts of viral replication and pathogenesis and provided novel insights into host cell biology. These findings are illustrated by the recent discovery of host-encoded factors that restrict HCV infection. In this review, we briefly discuss these restriction factors in different steps of HCV infection. In each case, we discuss how these restriction factors were identified, the mechanisms by which they inhibit HCV infection and their potential contribution to viral pathogenesis. PMID:26819515

  3. Additional hosts for Balansia epichloe in tall fescue pastures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The clavicipitalean fungi consist of a group of closely related species that are parasitic on grasses and sedges. These fungi are biotrophic and regarded as mutualist since they argument the hosts defenses to both biotic and abiotic stresses. The fungi consisted of species of Epichloe and Balansia...

  4. Selective recruitment of host factors by HSV-1 replication centers

    PubMed Central

    LANG, Feng-Chao; LI, Xin; VLADMIROVA, Olga; LI, Zhuo-Ran; CHEN, Gui-Jun; XIAO, Yu; LI, Li-Hong; LU, Dan-Feng; HAN, Hong-Bo; ZHOU, Ju-Min

    2015-01-01

    Herpes simplex virus type 1 (HSV-1) enters productive infection after infecting epithelial cells, where it controls the host nucleus to make viral proteins, starts viral DNA synthesis and assembles infectious virions. In this process, replicating viral genomes are organized into replication centers to facilitate viral growth. HSV-1 is known to use host factors, including host chromatin and host transcription regulators, to transcribe its genes; however, the invading virus also encounters host defense and stress responses to inhibit viral growth. Recently, we found that HSV-1 replication centers recruit host factor CTCF but exclude βH2A.X. Thus, HSV-1 replication centers may selectively recruit cellular factors needed for viral growth, while excluding host factors that are deleterious for viral transcription or replication. Here we report that the viral replication centers selectively excluded modified histone H3, including heterochromatin mark H3K9me3, H3S10P and active chromatin mark H3K4me3, but not unmodified H3. We found a dynamic association between the viral replication centers and host RNA polymerase II. The centers also recruited components of the DNA damage response pathway, including 53BP1, BRCA1 and host antiviral protein SP100. Importantly, we found that ATM kinase was needed for the recruitment of CTCF to the viral centers. These results suggest that the HSV-1 replication centers took advantage of host signaling pathways to actively recruit or exclude host factors to benefit viral growth. PMID:26018857

  5. Host factors governing resistance to Rhizoctonia solani

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the state of Washington, USA, annual losses of wheat attributed to soilborne necrotrophic fungal pathogens, such as Rhizoctonia solani, are estimated to be over US$100 million, and global estimates exceed US$1 billion. Host genetic resistance is a sustainable means of disease control that can be ...

  6. Neuroendocrine host factors and inflammatory disease susceptibility.

    PubMed Central

    Ligier, S; Sternberg, E M

    1999-01-01

    The etiology of autoimmune diseases is multifactorial, resulting from a combination of genetically predetermined host characteristics and environmental exposures. As the term autoimmune implies, immune dysfunction and dysregulated self-tolerance are key elements in the pathophysiology of all these diseases. The neuroendocrine and sympathetic nervous systems are increasingly recognized as modulators of the immune response at the levels of both early inflammation and specific immunity. As such, alterations in their response represent a potential mechanism by which pathologic autoimmunity may develop. Animal models of autoimmune diseases show pre-existing changes in neuroendocrine responses to a variety of stimuli, and both animal and human studies have shown altered stress responses in the setting of active immune activation. The potential role of the neuroendocrine system in linking environmental exposures and autoimmune diseases is 2-fold. First, it may represent a direct target for toxic compounds. Second, its inadequate function may result in the inappropriate response of the immune system to an environmental agent with immunogenic properties. This article reviews the relationship between autoimmune diseases and the neuroendocrine system and discusses the difficulties and pitfalls of investigating a physiologic response that is sensitive to such a multiplicity of environmental exposures. PMID:10502534

  7. Host restriction factors in retroviral infection: promises in virus-host interaction

    PubMed Central

    2012-01-01

    Retroviruses have an intricate life cycle. There is much to be learned from studying retrovirus-host interactions. Among retroviruses, the primate lentiviruses have one of the more complex genome structures with three categories of viral genes: structural, regulatory, and accessory genes. Over time, we have gained increasing understanding of the lentivirus life cycle from studying host factors that support virus replication. Similarly, studies on host restriction factors that inhibit viral replication have also made significant contributions to our knowledge. Here, we review recent progress on the rapidly growing field of restriction factors, focusing on the antiretroviral activities of APOBEC3G, TRIM5, tetherin, SAMHD1, MOV10, and cellular microRNAs (miRNAs), and the counter-activities of Vif, Vpu, Vpr, Vpx, and Nef. PMID:23254112

  8. The role of host genetic factors and host immunity in necrotic enteritis.

    PubMed

    Oh, Sung T; Lillehoj, Hyun S

    2016-06-01

    The increasing number of legislative restrictions and the voluntary withdrawal of antibiotic growth promoters worldwide will continue to impact poultry health and production. The rising incidence of Clostridium infections and development of necrotic enteritis (NE) in commercial chickens has been associated with the withdrawal of antibiotics. High-throughput genomic analysis of intestinal tissues from NE-afflicted chickens showed alterations in the local immunity and gut microbiota. Therefore, a better understanding of host- and environmentally related factors on Clostridium perfringens infections will be necessary for the development of effective sustainable strategies aimed to reduce the negative consequences of NE. In this short review, we summarize the current knowledge on the role of host genomics and immunity in NE. The limited progress in understanding the complexity of host-pathogen interactions in NE underscores the urgent need for more fundamental research in host immunity against Clostridium pathogens in order to develop effective control strategies against NE. PMID:26957203

  9. Interactions between host factors and the skin microbiome

    PubMed Central

    SanMiguel, Adam; Grice, Elizabeth A.

    2015-01-01

    The skin is colonized by an assemblage of microorganisms which, for the most part, peacefully coexist with their hosts. In some cases, these communities also provide vital functions to cutaneous health through the modulation of host factors. Recent studies have illuminated the role of anatomical skin site, gender, age, and the immune system in shaping the cutaneous ecosystem. Alterations to microbial communities have also been associated with, and likely contribute to, a number of cutaneous disorders. This review focuses on the host factors that shape and maintain skin microbial communities, and the reciprocal role of microbes in modulating skin immunity. A greater understanding of these interactions is critical to elucidating the forces that shape cutaneous populations and their contributions to skin homeostasis. This knowledge can also inform the tendency of perturbations to predispose and/or bring about certain skin disorders. PMID:25548803

  10. Host Cell Factors Involved in the Life Cycle of FMDV

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foot-and-Mouth Disease Virus (FMDV), like other RNA viruses, recruits various host cell factors to assist in translation and replication of the virus genome. While FMDV translation has been extensively investigated, much remains unknown regarding replication of the positive-sense RNA genome. In thi...

  11. Interaction between viral RNA silencing suppressors and host factors in plant immunity.

    PubMed

    Nakahara, Kenji S; Masuta, Chikara

    2014-08-01

    To elucidate events in the molecular arms race between the host and pathogen in evaluating plant immunity, a zigzag model is useful for uncovering aspects common to different host-pathogen interactions. By analogy of the steps in virus-host interactions with the steps in the standard zigzag model outlined in recent papers, we may regard RNA silencing as pattern-triggered immunity (PTI) against viruses, RNA silencing suppressors (RSSs) as effectors to overcome host RNA silencing and resistance gene (R-gene)-mediated defense as effector-triggered immunity (ETI) recognizing RSSs as avirulence proteins. However, because the standard zigzag model does not fully apply to some unique aspects in the interactions between a plant host and virus, we here defined a model especially designed for viruses. Although we simplified the phenomena involved in the virus-host interactions in the model, certain specific interactive steps can be explained by integrating additional host factors into the model. These host factors are thought to play an important role in maintaining the efficacy of the various steps in the main pathway of defense against viruses in this model for virus-plant interactions. For example, we propose candidates that may interact with viral RSSs to induce the resistance response. PMID:24875766

  12. Host Cell Factors in Filovirus Entry: Novel Players, New Insights

    PubMed Central

    Hofmann-Winkler, Heike; Kaup, Franziska; Pöhlmann, Stefan

    2012-01-01

    Filoviruses cause severe hemorrhagic fever in humans with high case-fatality rates. The cellular factors exploited by filoviruses for their spread constitute potential targets for intervention, but are incompletely defined. The viral glycoprotein (GP) mediates filovirus entry into host cells. Recent studies revealed important insights into the host cell molecules engaged by GP for cellular entry. The binding of GP to cellular lectins was found to concentrate virions onto susceptible cells and might contribute to the early and sustained infection of macrophages and dendritic cells, important viral targets. Tyrosine kinase receptors were shown to promote macropinocytic uptake of filoviruses into a subset of susceptible cells without binding to GP, while interactions between GP and human T cell Ig mucin 1 (TIM-1) might contribute to filovirus infection of mucosal epithelial cells. Moreover, GP engagement of the cholesterol transporter Niemann-Pick C1 was demonstrated to be essential for GP-mediated fusion of the viral envelope with a host cell membrane. Finally, mutagenic and structural analyses defined GP domains which interact with these host cell factors. Here, we will review the recent progress in elucidating the molecular interactions underlying filovirus entry and discuss their implications for our understanding of the viral cell tropism. PMID:23342362

  13. Legionella pneumophila glucosyltransferase inhibits host elongation factor 1A

    PubMed Central

    Belyi, Yury; Niggeweg, Ricarda; Opitz, Bastian; Vogelsgesang, Martin; Hippenstiel, Stefan; Wilm, Matthias; Aktories, Klaus

    2006-01-01

    Legionella pneumophila, the causal agent of Legionnaires' disease, is an intracellular parasite and invades and proliferates within different eukaryotic cells, including human alveolar macrophages. After several 100-fold multiplication within host cells, the pathogens are released for new invasion by induction of apoptosis or necrosis. Here we report that L. pneumophila produces a glucosyltransferase, which selectively modifies an ≈50-kDa mammalian protein by using UDP-glucose as a cosubstrate. MS analysis identified the protein substrate as the mammalian elongation factor (EF)1A. Legionella glucosyltransferase modifies its eukaryotic protein substrate at serine-53, which is located in the GTPase domain of the EF. Glucosylation of EF1A results in inhibition of eukaryotic protein synthesis and death of target cells. Our findings show a mode of inhibition of protein synthesis by microbial pathogens and offer a perspective for understanding of the host-pathogen interaction of L. pneumophila. PMID:17068130

  14. The Host Specificities of Baculovirus per os Infectivity Factors

    PubMed Central

    Song, Jingjiao; Wang, Xi; Hou, Dianhai; Huang, Huachao; Liu, Xijia; Deng, Fei; Wang, Hualin; Arif, Basil M.; Hu, Zhihong; Wang, Manli

    2016-01-01

    Baculoviruses are insect-specific pathogens with a generally narrow host ranges. Successful primary infection is initiated by the proper interaction of at least 8 conserved per os infectivity factors (PIFs) with the host’s midgut cells, a process that remains largely a mystery. In this study, we investigated the host specificities of the four core components of the PIF complex, P74, PIF1, PIF2 and PIF3 by using Helicoverpa armigera nucleopolyhedrovirus (HearNPV) backbone. The four pifs of HearNPV were replaced by their counterparts from a group I Autographa californica multiple nucleopolyhedrovirus (AcMNPV) or a group II Spodoptera litura nucleopolyhedrovirus (SpltNPV). Transfection and infection assays showed that all the recombinant viruses were able to produce infectious budded viruses (BVs) and were lethal to H. armigera larvae via intrahaemocoelic injection. However, feeding experiments using very high concentration of occlusion bodies demonstrated that all the recombinant viruses completely lost oral infectivity except SpltNPV pif3 substituted pif3-null HearNPV (vHaBacΔpif3-Sppif3-ph). Furthermore, bioassay result showed that the median lethal concentration (LC50) value of vHaBacΔpif3-Sppif3-ph was 23-fold higher than that of the control virus vHaBacΔpif3-Hapif3-ph, indicating that SpltNPV pif3 can only partially substitute the function of HearNPV pif3. These results suggested that most of PIFs tested have strict host specificities, which may account, at least in part, for the limited host ranges of baculoviruses. PMID:27454435

  15. Identification of FAM111A as an SV40 Host Range Restriction and Adenovirus Helper Factor

    PubMed Central

    Padi, Megha; Korkhin, Anna; James, Robert L.; Adelmant, Guillaume; Yoon, Rosa; Guo, Luxuan; Berrios, Christian; Zhang, Ying; Calderwood, Michael A.; Velmurgan, Soundarapandian; Cheng, Jingwei; Marto, Jarrod A.; Hill, David E.; Cusick, Michael E.; Vidal, Marc; Florens, Laurence; Washburn, Michael P.; Litovchick, Larisa; DeCaprio, James A.

    2012-01-01

    The small genome of polyomaviruses encodes a limited number of proteins that are highly dependent on interactions with host cell proteins for efficient viral replication. The SV40 large T antigen (LT) contains several discrete functional domains including the LXCXE or RB-binding motif, the DNA binding and helicase domains that contribute to the viral life cycle. In addition, the LT C-terminal region contains the host range and adenovirus helper functions required for lytic infection in certain restrictive cell types. To understand how LT affects the host cell to facilitate viral replication, we expressed full-length or functional domains of LT in cells, identified interacting host proteins and carried out expression profiling. LT perturbed the expression of p53 target genes and subsets of cell-cycle dependent genes regulated by the DREAM and the B-Myb-MuvB complexes. Affinity purification of LT followed by mass spectrometry revealed a specific interaction between the LT C-terminal region and FAM111A, a previously uncharacterized protein. Depletion of FAM111A recapitulated the effects of heterologous expression of the LT C-terminal region, including increased viral gene expression and lytic infection of SV40 host range mutants and adenovirus replication in restrictive cells. FAM111A functions as a host range restriction factor that is specifically targeted by SV40 LT. PMID:23093934

  16. Identification of FAM111A as an SV40 host range restriction and adenovirus helper factor.

    PubMed

    Fine, Debrah A; Rozenblatt-Rosen, Orit; Padi, Megha; Korkhin, Anna; James, Robert L; Adelmant, Guillaume; Yoon, Rosa; Guo, Luxuan; Berrios, Christian; Zhang, Ying; Calderwood, Michael A; Velmurgan, Soundarapandian; Cheng, Jingwei; Marto, Jarrod A; Hill, David E; Cusick, Michael E; Vidal, Marc; Florens, Laurence; Washburn, Michael P; Litovchick, Larisa; DeCaprio, James A

    2012-01-01

    The small genome of polyomaviruses encodes a limited number of proteins that are highly dependent on interactions with host cell proteins for efficient viral replication. The SV40 large T antigen (LT) contains several discrete functional domains including the LXCXE or RB-binding motif, the DNA binding and helicase domains that contribute to the viral life cycle. In addition, the LT C-terminal region contains the host range and adenovirus helper functions required for lytic infection in certain restrictive cell types. To understand how LT affects the host cell to facilitate viral replication, we expressed full-length or functional domains of LT in cells, identified interacting host proteins and carried out expression profiling. LT perturbed the expression of p53 target genes and subsets of cell-cycle dependent genes regulated by the DREAM and the B-Myb-MuvB complexes. Affinity purification of LT followed by mass spectrometry revealed a specific interaction between the LT C-terminal region and FAM111A, a previously uncharacterized protein. Depletion of FAM111A recapitulated the effects of heterologous expression of the LT C-terminal region, including increased viral gene expression and lytic infection of SV40 host range mutants and adenovirus replication in restrictive cells. FAM111A functions as a host range restriction factor that is specifically targeted by SV40 LT. PMID:23093934

  17. CRISPR Immunological Memory Requires a Host Factor for Specificity.

    PubMed

    Nuñez, James K; Bai, Lawrence; Harrington, Lucas B; Hinder, Tracey L; Doudna, Jennifer A

    2016-06-16

    Bacteria and archaea employ adaptive immunity against foreign genetic elements using CRISPR-Cas systems. To generate immunological memory, the Cas1-Cas2 protein complex captures 30-40 base pair segments of foreign DNA and catalyzes their integration into the host genome as unique spacer sequences. Although spacers are inserted strictly at the A-T-rich leader end of CRISPR loci in vivo, the molecular mechanism of leader-specific spacer integration remains poorly understood. Here we show that the E. coli integration host factor (IHF) protein is required for spacer acquisition in vivo and for integration into linear DNA in vitro. IHF binds to the leader sequence and induces a sharp DNA bend, allowing the Cas1-Cas2 integrase to catalyze the first integration reaction at the leader-repeat border. Together, these results reveal that Cas1-Cas2-mediated spacer integration requires IHF-induced target DNA bending and explain the elusive role of CRISPR leader sequences during spacer acquisition. PMID:27211867

  18. No Serological Evidence that Harbour Porpoises Are Additional Hosts of Influenza B Viruses

    PubMed Central

    Bodewes, Rogier; van de Bildt, Marco W. G.; van Elk, Cornelis E.; Bunskoek, Paulien E.; van de Vijver, David A. M. C.; Smits, Saskia L.; Osterhaus, Albert D. M. E.; Kuiken, Thijs

    2014-01-01

    Influenza A and B viruses circulate among humans causing epidemics almost annually. While various hosts for influenza A viruses exist, influenza B viruses have been detected only in humans and seals. However, recurrent infections of seals in Dutch coastal waters with influenza B viruses that are antigenetically distinct from influenza B viruses circulating among humans suggest that influenza B viruses have been introduced into this seal population by another, non-human, host. Harbour porpoises (Phocoena phocoena) are sympatric with seals in these waters and are also occasionally in close contact with humans after stranding and subsequent rehabilitation. In addition, virus attachment studies demonstrated that influenza B viruses can bind to cells of the respiratory tract of these animals. Therefore, we hypothesized that harbour porpoises might be a reservoir of influenza B viruses. In the present study, an unique set of serum samples from 79 harbour porpoises, stranded alive on the Dutch coast between 2003 and 2013, was tested for the presence of antibodies against influenza B viruses by use of the hemagglutination inhibition test and for antibodies against influenza A viruses by use of a competitive influenza A nucleoprotein ELISA. No antibodies were detected against either virus, suggesting that influenza A and B virus infections of harbour porpoises in Dutch coastal waters are not common, which was supported by statistical analysis of the dataset. PMID:24551217

  19. No serological evidence that harbour porpoises are additional hosts of influenza B viruses.

    PubMed

    Bodewes, Rogier; van de Bildt, Marco W G; van Elk, Cornelis E; Bunskoek, Paulien E; van de Vijver, David A M C; Smits, Saskia L; Osterhaus, Albert D M E; Kuiken, Thijs

    2014-01-01

    Influenza A and B viruses circulate among humans causing epidemics almost annually. While various hosts for influenza A viruses exist, influenza B viruses have been detected only in humans and seals. However, recurrent infections of seals in Dutch coastal waters with influenza B viruses that are antigenetically distinct from influenza B viruses circulating among humans suggest that influenza B viruses have been introduced into this seal population by another, non-human, host. Harbour porpoises (Phocoena phocoena) are sympatric with seals in these waters and are also occasionally in close contact with humans after stranding and subsequent rehabilitation. In addition, virus attachment studies demonstrated that influenza B viruses can bind to cells of the respiratory tract of these animals. Therefore, we hypothesized that harbour porpoises might be a reservoir of influenza B viruses. In the present study, an unique set of serum samples from 79 harbour porpoises, stranded alive on the Dutch coast between 2003 and 2013, was tested for the presence of antibodies against influenza B viruses by use of the hemagglutination inhibition test and for antibodies against influenza A viruses by use of a competitive influenza A nucleoprotein ELISA. No antibodies were detected against either virus, suggesting that influenza A and B virus infections of harbour porpoises in Dutch coastal waters are not common, which was supported by statistical analysis of the dataset. PMID:24551217

  20. Host genetic variation is a contributable factor for imperfectly-immunizing vaccination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vaccine protective efficacy is determined by multiple factors including host genetics, vaccine type, vaccine dosage, challenge virus virulence, challenge virus dose, and interval between vaccination and exposure to challenge viruses. About two decades ago, studies conducted to evaluate host genetic ...

  1. Early Vertebrate Evolution of the Host Restriction Factor Tetherin

    PubMed Central

    Heusinger, Elena; Kluge, Silvia F.; Kirchhoff, Frank

    2015-01-01

    release of newly formed progeny virions from infected cells. Although tetherin targets a broad range of enveloped viruses, including retro-, filo-, herpes-, and arenaviruses, the evolutionary origin of this restriction factor and its antiviral activity remained obscure. Here, we examined diverse vertebrate genomes for genes encoding cellular proteins that share with tetherin the highly unusual combination of an N-terminal transmembrane domain and a C-terminal glycosylphosphatidylinositol anchor. We show that tetherin orthologs are found in fish, reptiles, and birds and demonstrate that alligator tetherin efficiently inhibits the release of retroviral particles. Our findings identify tetherin as an evolutionarily ancient restriction factor and provide new important insights into the continuous arms race between viruses and their hosts. PMID:26401043

  2. Host factors determining the efficacy of hepatitis C treatment.

    PubMed

    Chuang, Wan-Long; Yu, Ming-Lung

    2013-01-01

    Combination therapy with pegylated interferon and ribavirin is the standard of care (SOC) for the treatment of chronic hepatitis C (CHC). Treating CHC with SOC may show a sustained virological response (SVR) in approximately 50-70 % of genotype 1 CHC patients and an SVR in 70-90 % of genotype 2 CHC patients. The genotype, baseline viral load, and viral kinetics (i.e., rapid virologic response and early virologic response) can be used as predictors of response-guided therapy. Nonetheless, host factors, e.g. age, ethnicity, insulin resistance, and genetic variations, may also play important roles in the SVR in CHC patients treated with SOC. Recent genome-wide association studies have demonstrated that single-nucleotide polymorphisms near the interleukin 28B gene (IL28B) were associated with SVR to treatment with SOC in CHC patients. The IL28B polymorphisms may contribute to the viral kinetics during treatment. Asian people have favorable IL28B polymorphisms. This factor may at least partly explain the high eradication rate of hepatitis C by SOC in Asia. Combination therapy with direct-acting antivirals (DAAs) and SOC can increase the SVR rates both in treatment-naïve and treatment-experienced patients. Although the IL28B polymorphisms also affect the SVR of triple therapy with SOC and first-generation protease inhibitors, pilot studies have demonstrated that potent DAAs might overcome the influence of IL28B polymorphisms. Thus, the treatment of hepatitis C virus infection could be simplified in the near future. PMID:23104468

  3. Deviance partitioning of host factors affecting parasitization in the European brown hare ( Lepus europaeus)

    NASA Astrophysics Data System (ADS)

    Alzaga, Vanesa; Tizzani, Paolo; Acevedo, Pelayo; Ruiz-Fons, Francisco; Vicente, Joaquín; Gortázar, Christian

    2009-10-01

    Deviance partitioning can provide new insights into the ecology of host-parasite interactions. We studied the host-related factors influencing parasite prevalence, abundance, and species richness in European brown hares ( Lepus europaeus) from northern Spain. We defined three groups of explanatory variables: host environment, host population, and individual factors. We hypothesised that parasite infection rates and species richness were determined by different host-related factors depending on the nature of the parasite (endo- or ectoparasite, direct or indirect life cycle). To assess the relative importance of these components, we used deviance partitioning, an innovative approach. The explained deviance (ED) was higher for parasite abundance models, followed by those of prevalence and then by species richness, suggesting that parasite abundance models may best describe the host factors influencing parasitization. Models for parasites with a direct life cycle yielded higher ED values than those for indirect life cycle ones. As a general trend, host individual factors explained the largest proportion of the ED, followed by host environmental factors and, finally, the interaction between host environmental and individual factors. Similar hierarchies were found for parasite prevalence, abundance, and species richness. Individual factors comprised the most relevant group of explanatory variables for both types of parasites. However, host environmental factors were also relevant in models for indirect life-cycle parasites. These findings are consistent with the idea of the host as the main habitat of the parasite; whereas, for indirect life-cycle parasites, transmission would be also modulated by environmental conditions. We suggest that parasitization can be used not only as an indicator of individual fitness but also as an indicator of environmental quality for the host. This research underlines the importance of monitoring parasite rates together with environmental

  4. Dynamic Regulation of Host Restriction Factor Expression over the Course of HIV-1 Infection In Vivo

    PubMed Central

    Abdel-Mohsen, Mohamed; Deng, Xutao; Hecht, Frederick M.; Pilcher, Christopher D.; Pillai, Satish K.; Nixon, Douglas F.

    2014-01-01

    In this study, we investigated the expression levels of host restriction factors in six untreated HIV-1-positive patients over the course of infection. We found that the host restriction factor gene expression profile consistently increased over time and was significantly associated with CD4+ T cell activation and viral load. Our data are among the first to demonstrate the dynamic nature of host restriction factors in vivo over time. PMID:25031350

  5. Select Host Restriction Factors Are Associated with HIV Persistence During Antiretroviral Therapy

    PubMed Central

    ABDEL-MOHSEN, Mohamed; WANG, Charlene; STRAIN, Matthew C.; LADA, Steven M.; DENG, Xutao; COCKERHAM, Leslie R.; PILCHER, Christopher D.; HECHT, Frederick M.; LIEGLER, Teri; RICHMAN, Douglas D.; DEEKS, Steven G.; PILLAI, Satish K.

    2015-01-01

    Objective The eradication of HIV necessitates elimination of the HIV latent reservoir. Identifying host determinants governing latency and reservoir size in the setting of antiretroviral therapy (ART) is an important step in developing strategies to cure HIV infection. We sought to determine the impact of cell-intrinsic immunity on the HIV latent reservoir. Design We investigated the relevance of a comprehensive panel of established anti-HIV-1 host restriction factors to multiple established virologic and immunologic measures of viral persistence in HIV-1-infected, ART-suppressed individuals. Methods We measured the mRNA expression of 42 anti-HIV-1 host restriction factors, levels of cell-associated HIV-1 RNA, levels of total pol and 2-LTR circle HIV-1 DNA, and immunophenotypes of CD4+ T cells in 72 HIV-1-infected subjects on suppressive ART (23 subjects initiated ART <1 year post-infection, and 49 subjects initiated ART >1 year post-infection). Correlations were analyzed using non-parametric tests. Results The enhanced expression of a few select host restriction factors, p21, schlafen 11, and PAF1, was strongly associated with reduced CD4+ T cell-associated HIV RNA during ART (p<0.001). In addition, our data suggested that ART perturbs the regulatory relationship between CD4+ T cell activation and restriction factor expression. Lastly, cell-intrinsic immune responses were significantly enhanced in subjects who initiated ART during early versus chronic infection, and may contribute to the reduced reservoir size observed in these individuals. Conclusions Intrinsic immune responses modulate HIV persistence during suppressive ART, and may be manipulated to enhance the efficacy of ART and promote viral eradication through reversal of latency in vivo. PMID:25602681

  6. Factors affecting host range in a generalist seed pathogen of semi-arid shrublands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    1. In weed biocontrol, the potential impact of the biocontrol organism on non-target species is a major concern traditionally addressed with laboratory experiments that measure potential or maximum host range. Several factors may operate to reduce realized host range relative to potential host rang...

  7. Human Genome-Wide RNAi Screen for Host Factors That Modulate Intracellular Salmonella Growth

    PubMed Central

    Thornbrough, Joshua M.; Hundley, Tom; Valdivia, Raphael; Worley, Micah J.

    2012-01-01

    Salmonella enterica is a bacterial pathogen of humans that can proliferate within epithelial cells as well as professional phagocytes of the immune system. While much has been learned about the microbial genes that influence the infectious process through decades of intensive research, relatively little is known about the host factors that affect infection. We performed a genome-wide siRNA screen to identify host genes that Salmonella enterica serovar Typhimurium (S. typhimurium) utilizes to facilitate growth within human epithelial cells. In this screen, with siRNAs targeting every predicted gene in the human genome, we identified 252 new human-host-susceptibility factors (HSFs) for S. typhimurium. We also identified 39 genes whose silencing results in increased intracellular growth of S. typhimurium. The HSFs identified are regulated most centrally by NFκB and associate with each other through an extremely dense network of interactions that center around a group of kinases. Most genes identified were not previously appreciated as playing roles in the intracellular lifecycle of S. enterica. Numerous HSFs identified with interesting characteristics that could play plausible roles in mediating intracellular microbial growth are discussed. Importantly, this study reveals significant overlap between the host network that supports S. typhimurium growth within human epithelial cells and the one that promotes the growth of Mycobacterium tuberculosis within human macrophages. In addition to providing much new information about the molecular mechanisms underlying S. enterica-host cell interplay, all 252 HSFs identified are candidates for new anti-microbial targets for controlling S. enterica infections, and some may provide broad-spectrum anti-microbial activity. PMID:22701604

  8. Screening for Host Factors Directly Interacting with RSV Protein: Microfluidics.

    PubMed

    Kipper, Sarit; Avrahami, Dorit; Bajorek, Monika; Gerber, Doron

    2016-01-01

    We present a high-throughput microfluidics platform to identify novel host cell binding partners of respiratory syncytial virus (RSV) matrix (M) protein. The device consists of thousands of reaction chambers controlled by micro-mechanical valves. The microfluidic device is mated to a microarray-printed custom-made gene library. These genes are then transcribed and translated on-chip, resulting in a protein array ready for binding to RSV M protein.Even small viral proteome, such as that of RSV, presents a challenge due to the fact that viral proteins are usually multifunctional and thus their interaction with the host is complex. Protein microarrays technology allows the interrogation of protein-protein interactions, which could possibly overcome obstacles by using conventional high throughput methods. Using microfluidics platform we have identified new host interactors of M involved in various cellular pathways. A number of microfluidics based assays have already provided novel insights into the virus-host interactome, and the results have important implications for future antiviral strategies aimed at targets of viral protein interactions with the host. PMID:27464694

  9. Improvement of modal scaling factors using mass additive technique

    NASA Technical Reports Server (NTRS)

    Zhang, Qiang; Allemang, Randall J.; Wei, Max L.; Brown, David L.

    1987-01-01

    A general investigation into the improvement of modal scaling factors of an experimental modal model using additive technique is discussed. Data base required by the proposed method consists of an experimental modal model (a set of complex eigenvalues and eigenvectors) of the original structure and a corresponding set of complex eigenvalues of the mass-added structure. Three analytical methods,i.e., first order and second order perturbation methods, and local eigenvalue modification technique, are proposed to predict the improved modal scaling factors. Difficulties encountered in scaling closely spaced modes are discussed. Methods to compute the necessary rotational modal vectors at the mass additive points are also proposed to increase the accuracy of the analytical prediction.

  10. Bifidobacteria-Host Interactions—An Update on Colonisation Factors

    PubMed Central

    Grimm, Verena; Westermann, Christina; Riedel, Christian U.

    2014-01-01

    Bifidobacteria are one of the predominant bacterial groups of the human intestinal microbiota and have important functional properties making them interesting for the food and dairy industries. Numerous in vitro and preclinical studies have shown beneficial effects of particular bifidobacterial strains or strain combinations on various health parameters of their hosts. This indicates the potential of bifidobacteria in alternative or supplementary therapeutic approaches in a number of diseased states. Based on these observations, bifidobacteria have attracted considerable interest by the food, dairy, and pharmaceutical industries and they are widely used as so-called probiotics. As a consequence of the rapidly increasing number of available bifidobacterial genome sequences and their analysis, there has been substantial progress in the identification of bifidobacterial structures involved in colonisation of and interaction with the host. With the present review, we aim to provide an update on the current knowledge on the mechanisms by which bifidobacteria colonise their hosts and exert health promoting effects. PMID:25295282

  11. Microsporidia Intracellular Development Relies on Myc Interaction Network Transcription Factors in the Host.

    PubMed

    Botts, Michael R; Cohen, Lianne B; Probert, Christopher S; Wu, Fengting; Troemel, Emily R

    2016-01-01

    Microsporidia are ubiquitous parasites that infect a wide range of animal hosts, and these fungal-related microbes undergo their entire replicative lifecycle inside of host cells. Despite being widespread in the environment and causing medical and agricultural harm, virtually nothing is known about the host factors important to facilitate their growth and development inside of host cells. Here, we perform a genetic screen to identify host transcription factors important for development of the microsporidian pathogen Nematocida parisii inside intestinal cells of its natural host, the nematode Caenorhabditis elegans Through this screen, we identified the C. elegans Myc family of transcription factors as key host regulators of microsporidia growth and development. The Mad-like transcription factor MDL-1, and the Max-like transcription factors MXL-1 and MXL-2 promote pathogen levels, while the Myc-Mondo-like transcription factor MML-1 inhibits pathogen levels. We used epistasis analysis to show that MDL-1 and MXL-1, which are thought to function as a heterodimer, appear to be acting canonically. In contrast, MXL-2 and MML-1, which are also thought to function as a heterodimer, appear to be acting in separate pathways (noncanonically) in the context of pathogen infection. We also found that both MDL-1::GFP and MML-1::GFP are expressed in intestinal cells during infection. These findings provide novel insight into the host transcription factors that regulate microsporidia development. PMID:27402359

  12. Microsporidia Intracellular Development Relies on Myc Interaction Network Transcription Factors in the Host

    PubMed Central

    Botts, Michael R.; Cohen, Lianne B.; Probert, Christopher S.; Wu, Fengting; Troemel, Emily R.

    2016-01-01

    Microsporidia are ubiquitous parasites that infect a wide range of animal hosts, and these fungal-related microbes undergo their entire replicative lifecycle inside of host cells. Despite being widespread in the environment and causing medical and agricultural harm, virtually nothing is known about the host factors important to facilitate their growth and development inside of host cells. Here, we perform a genetic screen to identify host transcription factors important for development of the microsporidian pathogen Nematocida parisii inside intestinal cells of its natural host, the nematode Caenorhabditis elegans. Through this screen, we identified the C. elegans Myc family of transcription factors as key host regulators of microsporidia growth and development. The Mad-like transcription factor MDL-1, and the Max-like transcription factors MXL-1 and MXL-2 promote pathogen levels, while the Myc-Mondo-like transcription factor MML-1 inhibits pathogen levels. We used epistasis analysis to show that MDL-1 and MXL-1, which are thought to function as a heterodimer, appear to be acting canonically. In contrast, MXL-2 and MML-1, which are also thought to function as a heterodimer, appear to be acting in separate pathways (noncanonically) in the context of pathogen infection. We also found that both MDL-1::GFP and MML-1::GFP are expressed in intestinal cells during infection. These findings provide novel insight into the host transcription factors that regulate microsporidia development. PMID:27402359

  13. The Pathogen-Host Interactions database (PHI-base): additions and future developments

    PubMed Central

    Urban, Martin; Pant, Rashmi; Raghunath, Arathi; Irvine, Alistair G.; Pedro, Helder; Hammond-Kosack, Kim E.

    2015-01-01

    Rapidly evolving pathogens cause a diverse array of diseases and epidemics that threaten crop yield, food security as well as human, animal and ecosystem health. To combat infection greater comparative knowledge is required on the pathogenic process in multiple species. The Pathogen-Host Interactions database (PHI-base) catalogues experimentally verified pathogenicity, virulence and effector genes from bacterial, fungal and protist pathogens. Mutant phenotypes are associated with gene information. The included pathogens infect a wide range of hosts including humans, animals, plants, insects, fish and other fungi. The current version, PHI-base 3.6, available at http://www.phi-base.org, stores information on 2875 genes, 4102 interactions, 110 host species, 160 pathogenic species (103 plant, 3 fungal and 54 animal infecting species) and 181 diseases drawn from 1243 references. Phenotypic and gene function information has been obtained by manual curation of the peer-reviewed literature. A controlled vocabulary consisting of nine high-level phenotype terms permits comparisons and data analysis across the taxonomic space. PHI-base phenotypes were mapped via their associated gene information to reference genomes available in Ensembl Genomes. Virulence genes and hotspots can be visualized directly in genome browsers. Future plans for PHI-base include development of tools facilitating community-led curation and inclusion of the corresponding host target(s). PMID:25414340

  14. Evidence for additive and interaction effects of host genotype and infection in malaria

    PubMed Central

    Idaghdour, Youssef; Quinlan, Jacklyn; Goulet, Jean-Philippe; Berghout, Joanne; Gbeha, Elias; Bruat, Vanessa; de Malliard, Thibault; Grenier, Jean-Christophe; Gomez, Selma; Gros, Philippe; Rahimy, Mohamed Chérif; Sanni, Ambaliou; Awadalla, Philip

    2012-01-01

    The host mechanisms responsible for protection against malaria remain poorly understood, with only a few protective genetic effects mapped in humans. Here, we characterize a host-specific genome-wide signature in whole-blood transcriptomes of Plasmodium falciparum-infected West African children and report a demonstration of genotype-by-infection interactions in vivo. Several associations involve transcripts sensitive to infection and implicate complement system, antigen processing and presentation, and T-cell activation (i.e., SLC39A8, C3AR1, FCGR3B, RAD21, RETN, LRRC25, SLC3A2, and TAPBP), including one association that validated a genome-wide association candidate gene (SCO1), implicating binding variation within a noncoding regulatory element. Gene expression profiles in mice infected with Plasmodium chabaudi revealed and validated similar responses and highlighted specific pathways and genes that are likely important responders in both hosts. These results suggest that host variation and its interplay with infection affect children’s ability to cope with infection and suggest a polygenic model mounted at the transcriptional level for susceptibility. PMID:22949651

  15. The Pathogen-Host Interactions database (PHI-base): additions and future developments.

    PubMed

    Urban, Martin; Pant, Rashmi; Raghunath, Arathi; Irvine, Alistair G; Pedro, Helder; Hammond-Kosack, Kim E

    2015-01-01

    Rapidly evolving pathogens cause a diverse array of diseases and epidemics that threaten crop yield, food security as well as human, animal and ecosystem health. To combat infection greater comparative knowledge is required on the pathogenic process in multiple species. The Pathogen-Host Interactions database (PHI-base) catalogues experimentally verified pathogenicity, virulence and effector genes from bacterial, fungal and protist pathogens. Mutant phenotypes are associated with gene information. The included pathogens infect a wide range of hosts including humans, animals, plants, insects, fish and other fungi. The current version, PHI-base 3.6, available at http://www.phi-base.org, stores information on 2875 genes, 4102 interactions, 110 host species, 160 pathogenic species (103 plant, 3 fungal and 54 animal infecting species) and 181 diseases drawn from 1243 references. Phenotypic and gene function information has been obtained by manual curation of the peer-reviewed literature. A controlled vocabulary consisting of nine high-level phenotype terms permits comparisons and data analysis across the taxonomic space. PHI-base phenotypes were mapped via their associated gene information to reference genomes available in Ensembl Genomes. Virulence genes and hotspots can be visualized directly in genome browsers. Future plans for PHI-base include development of tools facilitating community-led curation and inclusion of the corresponding host target(s). PMID:25414340

  16. Characterization of the Host Factors Required for Hepadnavirus Covalently Closed Circular (ccc) DNA Formation

    PubMed Central

    Zhou, Tianlun; Block, Timothy M.; Guo, Ju-Tao

    2012-01-01

    Synthesis of the covalently closed circular (ccc) DNA is a critical, but not well-understood step in the life cycle of hepadnaviruses. Our previous studies favor a model that removal of genome-linked viral DNA polymerase occurs in the cytoplasm and the resulting deproteinized relaxed circular DNA (DP-rcDNA) is subsequently transported into the nucleus and converted into cccDNA. In support of this model, our current study showed that deproteinization of viral double-stranded linear (dsl) DNA also took place in the cytoplasm. Furthermore, we demonstrated that Ku80, a component of non-homologous end joining DNA repair pathway, was essential for synthesis of cccDNA from dslDNA, but not rcDNA. In an attempt to identify additional host factors regulating cccDNA biosynthesis, we found that the DP-rcDNA was produced in all tested cell lines that supported DHBV DNA replication, but cccDNA was only synthesized in the cell lines that accumulated high levels of DP-rcDNA, except for NCI-H322M and MDBK cells, which failed to synthesize cccDNA despite of the existence of nuclear DP-rcDNA. The results thus imply that while removal of the genome-linked viral DNA polymerase is most likely catalyzed by viral or ubiquitous host function(s), nuclear factors required for the conversion of DP-rcDNA into cccDNA and/or its maintenance are deficient in the above two cell lines, which could be useful tools for identification of the elusive host factors essential for cccDNA biosynthesis or maintenance. PMID:22912842

  17. Iron acquisition from Pseudomonas aeruginosa siderophores by human phagocytes: an additional mechanism of host defense through iron sequestration?

    PubMed

    Britigan, B E; Rasmussen, G T; Olakanmi, O; Cox, C D

    2000-03-01

    Chelation of iron to iron-binding proteins is a strategy of host defense. Some pathogens counter this via the secretion of low-molecular-weight iron-chelating agents (siderophores). Human phagocytes possess a high-capacity mechanism for iron acquisition from low-molecular-weight iron chelates. Efficient acquisition and sequestration of iron bound to bacterial siderophores by host phagocytes could provide a secondary mechanism to limit microbial access to iron. In the present work we report that human neutrophils, macrophages, and myeloid cell lines can acquire iron from the two Pseudomonas aeruginosa siderophores. Analogous to iron acquisition from other low-molecular-weight chelates, iron acquisition from the siderophores is ATP independent, induced by multivalent cationic metals, and unaffected by inhibitors of endocytosis and pinocytosis. In vivo, this process could serve as an additional mechanism of host defense to limit iron availability to invading siderophore-producing microbes. PMID:10678937

  18. Iron Acquisition from Pseudomonas aeruginosa Siderophores by Human Phagocytes: an Additional Mechanism of Host Defense through Iron Sequestration?

    PubMed Central

    Britigan, Bradley E.; Rasmussen, George T.; Olakanmi, Oyebode; Cox, Charles D.

    2000-01-01

    Chelation of iron to iron-binding proteins is a strategy of host defense. Some pathogens counter this via the secretion of low-molecular-weight iron-chelating agents (siderophores). Human phagocytes possess a high-capacity mechanism for iron acquisition from low-molecular-weight iron chelates. Efficient acquisition and sequestration of iron bound to bacterial siderophores by host phagocytes could provide a secondary mechanism to limit microbial access to iron. In the present work we report that human neutrophils, macrophages, and myeloid cell lines can acquire iron from the two Pseudomonas aeruginosa siderophores. Analogous to iron acquisition from other low-molecular-weight chelates, iron acquisition from the siderophores is ATP independent, induced by multivalent cationic metals, and unaffected by inhibitors of endocytosis and pinocytosis. In vivo, this process could serve as an additional mechanism of host defense to limit iron availability to invading siderophore-producing microbes. PMID:10678937

  19. Targeting Host Factors to Treat West Nile and Dengue Viral Infections

    PubMed Central

    Krishnan, Manoj N.; Garcia-Blanco, Mariano A.

    2014-01-01

    West Nile (WNV) and Dengue (DENV) viruses are major arboviral human pathogens belonging to the genus Flavivirus. At the current time, there are no approved prophylactics (e.g., vaccines) or specific therapeutics available to prevent or treat human infections by these pathogens. Due to their minimal genome, these viruses require many host molecules for their replication and this offers a therapeutic avenue wherein host factors can be exploited as treatment targets. Since several host factors appear to be shared by many flaviviruses the strategy may result in pan-flaviviral inhibitors and may also attenuate the rapid emergence of drug resistant mutant viruses. The scope of this strategy is greatly enhanced by the recent en masse identification of host factors impacting on WNV and DENV infection. Excellent proof-of-principle experimental demonstrations for host-targeted control of infection and infection-induced pathogenesis have been reported for both WNV and DENV. These include exploiting not only those host factors supporting infection, but also targeting host processes contributing to pathogenesis and innate immune responses. While these early studies validated the host-targeting approach, extensive future investigations spanning a range of aspects are needed for a successful deployment in humans. PMID:24517970

  20. Targeting host factors to treat West Nile and dengue viral infections.

    PubMed

    Krishnan, Manoj N; Garcia-Blanco, Mariano A

    2014-02-01

    West Nile (WNV) and Dengue (DENV) viruses are major arboviral human pathogens belonging to the genus Flavivirus. At the current time, there are no approved prophylactics (e.g., vaccines) or specific therapeutics available to prevent or treat human infections by these pathogens. Due to their minimal genome, these viruses require many host molecules for their replication and this offers a therapeutic avenue wherein host factors can be exploited as treatment targets. Since several host factors appear to be shared by many flaviviruses the strategy may result in pan-flaviviral inhibitors and may also attenuate the rapid emergence of drug resistant mutant viruses. The scope of this strategy is greatly enhanced by the recent en masse identification of host factors impacting on WNV and DENV infection. Excellent proof-of-principle experimental demonstrations for host-targeted control of infection and infection-induced pathogenesis have been reported for both WNV and DENV. These include exploiting not only those host factors supporting infection, but also targeting host processes contributing to pathogenesis and innate immune responses. While these early studies validated the host-targeting approach, extensive future investigations spanning a range of aspects are needed for a successful deployment in humans. PMID:24517970

  1. Leishmania-encoded orthologs of macrophage migration inhibitory factor regulate host immunity to promote parasite persistence.

    PubMed

    Holowka, Thomas; Castilho, Tiago M; Garcia, Alvaro Baeza; Sun, Tiffany; McMahon-Pratt, Diane; Bucala, Richard

    2016-06-01

    Leishmania major encodes 2 orthologs of the cytokine macrophage migration inhibitory factor (MIF), whose functions in parasite growth or in the host-parasite interaction are unknown. To determine the importance of Leishmania-encoded MIF, both LmMIF genes were removed to produce an mif(-/-) strain of L. major This mutant strain replicated normally in vitro but had a 2-fold increased susceptibility to clearance by macrophages. Mice infected with mif(-/-) L. major, when compared to the wild-type strain, also showed a 3-fold reduction in parasite burden. Microarray and functional analyses revealed a reduced ability of mif(-/-) L. major to activate antigen-presenting cells, resulting in a 2-fold reduction in T-cell priming. In addition, there was a reduction in inflammation and effector CD4 T-cell formation in mif(-/-) L. major-infected mice when compared to mice infected with wild-type L. major Notably, effector CD4 T cells that developed during infection with mif(-/-) L. major demonstrated statistically significant differences in markers of functional exhaustion, including increased expression of IFN-γ and IL-7R, reduced expression of programmed death-1, and decreased apoptosis. These data support a role for LmMIF in promoting parasite persistence by manipulating the host response to increase the exhaustion and depletion of protective CD4 T cells.-Holowka, T., Castilho, T. M., Baeza Garcia, A., Sun, T., McMahon-Pratt, D., Bucala, R. Leishmania-encoded orthologs of macrophage migration inhibitory factor regulate host immunity to promote parasite persistence. PMID:26956417

  2. Virulence factors and strategies of Leptopilina spp.: selective responses in Drosophila hosts.

    PubMed

    Lee, Mark J; Kalamarz, Marta E; Paddibhatla, Indira; Small, Chiyedza; Rajwani, Roma; Govind, Shubha

    2009-01-01

    To ensure survival, parasitic wasps of Drosophila have evolved strategies to optimize host development to their advantage. They also produce virulence factors that allow them to overcome or evade host defense. Wasp infection provokes cellular and humoral defense reactions, resulting in alteration in gene expression of the host. The activation of these reactions is controlled by conserved mechanisms shared by other invertebrate and vertebrate animals. Application of genomics and bioinformatics approaches is beginning to reveal comparative host gene expression changes after infection by different parasitic wasps. We analyze this comparison in the context of host physiology and immune cells, as well as the biology of the venom factors that wasps introduce into their hosts during oviposition. We compare virulence strategies of Leptopilina boulardi and L. heterotoma, in relation to genome-wide changes in gene expression in the fly hosts after infection. This analysis highlights fundamental differences in the changes that the host undergoes in its immune and general physiology in response to the two parasitic wasps. Such a comparative approach has the potential of revealing mechanisms governing the evolution of pathogenicity and how it impacts host range. PMID:19773069

  3. Virulence Factors and Strategies of Leptopilina spp.: Selective Responses in Drosophila Hosts

    PubMed Central

    Lee, Mark J.; Kalamarz, Marta E.; Paddibhatla, Indira; Small, Chiyedza; Rajwani, Roma; Govind, Shubha

    2010-01-01

    To ensure survival, parasitic wasps of Drosophila have evolved strategies to optimize host development to their advantage. They also produce virulence factors that allow them to overcome or evade host defense. Wasp infection provokes cellular and humoral defense reactions, resulting in alteration in gene expression of the host. The activation of these reactions is controlled by conserved mechanisms shared by other invertebrate and vertebrate animals. Application of genomics and bioinformatics approaches is beginning to reveal comparative host gene expression changes after infection by different parasitic wasps. We analyze this comparison in the context of host physiology and immune cells, as well as the biology of the venom factors that wasps introduce into their hosts during oviposition. We compare virulence strategies of Leptopilina boulardi and L. heterotoma, in relation to genome-wide changes in gene expression in the fly hosts after infection. This analysis highlights fundamental differences in the changes that the host undergoes in its immune and general physiology in response to the two parasitic wasps. Such a comparative approach has the potential of revealing mechanisms governing the evolution of pathogenicity and how it impacts host range. PMID:19773069

  4. Bacterium-Generated Nitric Oxide Hijacks Host Tumor Necrosis Factor Alpha Signaling and Modulates the Host Cell Cycle In Vitro

    PubMed Central

    Mocca, Brian

    2012-01-01

    In mammalian cells, nitric oxide (NO·) is an important signal molecule with concentration-dependent and often controversial functions of promoting cell survival and inducing cell death. An inducible nitric oxide synthase (iNOS) in various mammalian cells produces higher levels of NO· from l-arginine upon infections to eliminate pathogens. In this study, we reveal novel pathogenic roles of NO· generated by bacteria in bacterium-host cell cocultures using Moraxella catarrhalis, a respiratory tract disease-causing bacterium, as a biological producer of NO·. We recently demonstrated that M. catarrhalis cells that express the nitrite reductase (AniA protein) can produce NO· by reducing nitrite. Our study suggests that, in the presence of pathophysiological levels of nitrite, this opportunistic pathogen hijacks host cell signaling and modulates host gene expression through its ability to produce NO· from nitrite. Bacterium-generated NO· significantly increases the secretion of tumor necrosis factor alpha (TNF-α) and modulates the expression of apoptotic proteins, therefore triggering host cell programmed death partially through TNF-α signaling. Furthermore, our study reveals that bacterium-generated NO· stalls host cell division and directly results in the death of dividing cells by reducing the levels of an essential regulator of cell division. This study provides unique insight into why NO· may exert more severe cytotoxic effects on fast growing cells, providing an important molecular basis for NO·-mediated pathogenesis in infections and possible therapeutic applications of NO·-releasing molecules in tumorigenesis. This study strongly suggests that bacterium-generated NO· can play important pathogenic roles during infections. PMID:22636782

  5. Yersinia virulence factors - a sophisticated arsenal for combating host defences.

    PubMed

    Atkinson, Steve; Williams, Paul

    2016-01-01

    The human pathogens Yersinia pseudotuberculosis and Yersinia enterocolitica cause enterocolitis, while Yersinia pestis is responsible for pneumonic, bubonic, and septicaemic plague. All three share an infection strategy that relies on a virulence factor arsenal to enable them to enter, adhere to, and colonise the host while evading host defences to avoid untimely clearance. Their arsenal includes a number of adhesins that allow the invading pathogens to establish a foothold in the host and to adhere to specific tissues later during infection. When the host innate immune system has been activated, all three pathogens produce a structure analogous to a hypodermic needle. In conjunction with the translocon, which forms a pore in the host membrane, the channel that is formed enables the transfer of six 'effector' proteins into the host cell cytoplasm. These proteins mimic host cell proteins but are more efficient than their native counterparts at modifying the host cell cytoskeleton, triggering the host cell suicide response. Such a sophisticated arsenal ensures that yersiniae maintain the upper hand despite the best efforts of the host to counteract the infecting pathogen. PMID:27347390

  6. Yersinia virulence factors - a sophisticated arsenal for combating host defences

    PubMed Central

    Atkinson, Steve; Williams, Paul

    2016-01-01

    The human pathogens Yersinia pseudotuberculosis and Yersinia enterocolitica cause enterocolitis, while Yersinia pestis is responsible for pneumonic, bubonic, and septicaemic plague. All three share an infection strategy that relies on a virulence factor arsenal to enable them to enter, adhere to, and colonise the host while evading host defences to avoid untimely clearance. Their arsenal includes a number of adhesins that allow the invading pathogens to establish a foothold in the host and to adhere to specific tissues later during infection. When the host innate immune system has been activated, all three pathogens produce a structure analogous to a hypodermic needle. In conjunction with the translocon, which forms a pore in the host membrane, the channel that is formed enables the transfer of six ‘effector’ proteins into the host cell cytoplasm. These proteins mimic host cell proteins but are more efficient than their native counterparts at modifying the host cell cytoskeleton, triggering the host cell suicide response. Such a sophisticated arsenal ensures that yersiniae maintain the upper hand despite the best efforts of the host to counteract the infecting pathogen. PMID:27347390

  7. Hepatitis C: viral and host factors associated with non-response to pegylated interferon plus ribavirin

    PubMed Central

    Asselah, Tarik; Estrabaud, Emilie; Bieche, Ivan; Lapalus, Martine; De Muynck, Simon; Vidaud, Michel; Saadoun, David; Soumelis, Vassili; Marcellin, Patrick

    2010-01-01

    Treatment for chronic hepatitis C virus (HCV) infection has evolved considerably in the last years. The standard of care (SOC) for HCV infection consists in the combination of pegylated interferon (PEG-IFN) plus ribavirin. However, it only induces a sustained virological response (SVR) in half of genotype 1-infected patients. Several viral and host factors have been associated with non-response: steatosis, obesity, insulin resistance, age, male sex, ethnicity and genotypes. Many studies have demonstrated that in non-responders, some interferon-stimulated genes were upregulated before treatment. Those findings associated to clinical, biochemical and histological data may help detect responders before starting any treatment. This is a very important issue because the standard treatment is physically and economically demanding. The future of HCV treatment would probably consist in the addition of specifically targeted antiviral therapy for HCV such as protease and/or polymerase inhibitors to the SOC. In genotype 1 patients, very promising results have been reported when the protease inhibitor telaprevir or boceprevir is added to the SOC. It increases the SVR rates from approximately 50% (PEG-IFN plus ribavirin) to 70% (for patients treated with a combination of PEG-IFN plus ribavirin plus telaprevir). Different elements are associated with non-response: (i) viral factors, (ii) host factors and (iii) molecular mechanisms induced by HCV proteins to inhibit the IFN signalling pathway. The goal of this review is to present the mechanisms of non-response, to overcome it and to identify factors that can help to predict the response to anti-HCV therapy. PMID:20633102

  8. Structural basis for antagonizing a host restriction factor by C7 family of poxvirus host-range proteins

    PubMed Central

    Meng, Xiangzhi; Krumm, Brian; Li, Yongchao; Deng, Junpeng; Xiang, Yan

    2015-01-01

    Human sterile alpha motif domain-containing 9 (SAMD9) protein is a host restriction factor for poxviruses, but it can be overcome by some poxvirus host-range proteins that share homology with vaccinia virus C7 protein. To understand the mechanism of action for this important family of host-range factors, we determined the crystal structures of C7 and myxoma virus M64, a C7 family member that is unable to antagonize SAMD9. Despite their different functions and only 23% sequence identity, the two proteins have very similar overall structures, displaying a previously unidentified fold comprised of a compact 12-stranded antiparallel β-sandwich wrapped in two short α helices. Extensive structure-guided mutagenesis of C7 identified three loops clustered on one edge of the β sandwich as critical for viral replication and binding with SAMD9. The loops are characterized with functionally important negatively charged, positively charged, and hydrophobic residues, respectively, together forming a unique “three-fingered molecular claw.” The key residues of the claw are not conserved in two C7 family members that do not antagonize SAMD9 but are conserved in distantly related C7 family members from four poxvirus genera that infect diverse mammalian species. Indeed, we found that all in the latter group of proteins bind SAMD9. Taken together, our data indicate that diverse mammalian poxviruses use a conserved molecular claw in a C7-like protein to target SAMD9 and overcome host restriction. PMID:26578811

  9. Identification and Structural Basis of Binding to Host Lung Glycogen by Streptococcal Virulence Factors

    SciTech Connect

    Lammerts van Bueren,A.; Higgins, M.; Wang, D.; Burke, R.; Boraston, A.

    2007-01-01

    The ability of pathogenic bacteria to recognize host glycans is often essential to their virulence. Here we report structure-function studies of previously uncharacterized glycogen-binding modules in the surface-anchored pullulanases from Streptococcus pneumoniae (SpuA) and Streptococcus pyogenes (PulA). Multivalent binding to glycogen leads to a strong interaction with alveolar type II cells in mouse lung tissue. X-ray crystal structures of the binding modules reveal a novel fusion of tandem modules into single, bivalent functional domains. In addition to indicating a structural basis for multivalent attachment, the structure of the SpuA modules in complex with carbohydrate provides insight into the molecular basis for glycogen specificity. This report provides the first evidence that intracellular lung glycogen may be a novel target of pathogenic streptococci and thus provides a rationale for the identification of the streptococcal {alpha}-glucan-metabolizing machinery as virulence factors.

  10. Identification and structural basis of binding to host lung glycogen by streptococcal virulence factors.

    PubMed

    van Bueren, Alicia Lammerts; Higgins, Melanie; Wang, Diana; Burke, Robert D; Boraston, Alisdair B

    2007-01-01

    The ability of pathogenic bacteria to recognize host glycans is often essential to their virulence. Here we report structure-function studies of previously uncharacterized glycogen-binding modules in the surface-anchored pullulanases from Streptococcus pneumoniae (SpuA) and Streptococcus pyogenes (PulA). Multivalent binding to glycogen leads to a strong interaction with alveolar type II cells in mouse lung tissue. X-ray crystal structures of the binding modules reveal a novel fusion of tandem modules into single, bivalent functional domains. In addition to indicating a structural basis for multivalent attachment, the structure of the SpuA modules in complex with carbohydrate provides insight into the molecular basis for glycogen specificity. This report provides the first evidence that intracellular lung glycogen may be a novel target of pathogenic streptococci and thus provides a rationale for the identification of the streptococcal alpha-glucan-metabolizing machinery as virulence factors. PMID:17187076

  11. Virus and Host Factors Affecting the Clinical Outcome of Bluetongue Virus Infection

    PubMed Central

    Caporale, Marco; Di Gialleonorado, Luigina; Janowicz, Anna; Wilkie, Gavin; Shaw, Andrew; Savini, Giovanni; Van Rijn, Piet A.; Mertens, Peter; Di Ventura, Mauro

    2014-01-01

    ABSTRACT Bluetongue is a major infectious disease of ruminants caused by bluetongue virus (BTV), an arbovirus transmitted by Culicoides. Here, we assessed virus and host factors influencing the clinical outcome of BTV infection using a single experimental framework. We investigated how mammalian host species, breed, age, BTV serotypes, and strains within a serotype affect the clinical course of bluetongue. Results obtained indicate that in small ruminants, there is a marked difference in the susceptibility to clinical disease induced by BTV at the host species level but less so at the breed level. No major differences in virulence were found between divergent serotypes (BTV-8 and BTV-2). However, we observed striking differences in virulence between closely related strains of the same serotype collected toward the beginning and the end of the European BTV-8 outbreak. As observed previously, differences in disease severity were also observed when animals were infected with either blood from a BTV-infected animal or from the same virus isolated in cell culture. Interestingly, with the exception of two silent mutations, full viral genome sequencing showed identical consensus sequences of the virus before and after cell culture isolation. However, deep sequencing analysis revealed a marked decrease in the genetic diversity of the viral population after passaging in mammalian cells. In contrast, passaging in Culicoides cells increased the overall number of low-frequency variants compared to virus never passaged in cell culture. Thus, Culicoides might be a source of new viral variants, and viral population diversity can be another factor influencing BTV virulence. IMPORTANCE Bluetongue is one of the major infectious diseases of ruminants. It is caused by an arbovirus known as bluetongue virus (BTV). The clinical outcome of BTV infection is extremely variable. We show that there are clear links between the severity of bluetongue and the mammalian host species infected

  12. Host and donor risk factors before and after liver transplantation that impact HCV recurrence.

    PubMed

    Berenguer, Marina

    2003-11-01

    1. The natural history of hepatitis C after liver transplantation is variable. Several factors, including those related to the virus, the host, the environment and the donor, are probably implicated in the outcome. 2. The immune status per se likely represents the main significant variable in influencing disease severity in hepatitis C virus-infected patients. Findings that support this statement include the higher aggressivity of hepatitis C in immunocompromised liver transplant recipients as compared with that observed in immunocompetent patients, both before and after the development of compensated cirrhosis, and the significant association described between the degree of immunosuppression and disease severity. 3. Similar to that observed in the immunocompetent population, the age at the time of infection (age of the donor) strongly affects posttransplantation hepatitis C virus-related disease progression. 4. Hepatitis C-related disease progression is faster in patients who underwent transplantation in recent years as compared with those who underwent transplantation in earlier cohorts. The increasing age of the donor and the use of stronger immunosuppression may, in part, explain the worse outcomes seen in recent years. 5. Additional host-related variables predictive of outcome include the immunogenetic background, the timing of recurrence, and the early histologic findings. PMID:14586894

  13. The correlated factors of the uneven performances of the CDM host countries

    NASA Astrophysics Data System (ADS)

    Zhu, Jinshan

    2012-03-01

    The Kyoto Protocol’s Clean Development Mechanism (CDM) has experienced a rapid growth. Up to 2010, 2763 projects have been registered, standing for about 433 million ton CO2 equivalent (CO2-eq.) of annual carbon credits. However, the performances of CDM host countries are remarkably unbalanced. Previous literature suggested that economic and investment conditions, energy intensity, energy structure, the share of annual carbon credits from high global warming potential (GWP) green house gas (GHG), capacity and institutional buildings of domestic CDM governance can play important roles in promoting CDM. This quantitative analysis shows that domestic economic and investment conditions are the most decisive factors determining the performance of the CDM host countries. Additionally, the influence of carbon intensity of energy consumption is relatively modest, and energy intensity of GDP as well as the share of annual carbon credits from high GWP GHG is less significant. Moreover, several leading CDM countries are not as successful as they seem to be, when the influences of their vast territories, distinguished economic and investment conditions are excluded. Therefore, to simply transplant the CDM governances of these countries can hardly guarantee that other countries will boost their carbon credit outputs.

  14. Induction of virulence factors in Giardia duodenalis independent of host attachment

    PubMed Central

    Emery, Samantha J.; Mirzaei, Mehdi; Vuong, Daniel; Pascovici, Dana; Chick, Joel M.; Lacey, Ernest; Haynes, Paul A.

    2016-01-01

    Giardia duodenalis is responsible for the majority of parasitic gastroenteritis in humans worldwide. Host-parasite interaction models in vitro provide insights into disease and virulence and help us to understand pathogenesis. Using HT-29 intestinal epithelial cells (IEC) as a model we have demonstrated that initial sensitisation by host secretions reduces proclivity for trophozoite attachment, while inducing virulence factors. Host soluble factors triggered up-regulation of membrane and secreted proteins, including Tenascins, Cathepsin-B precursor, cystatin, and numerous Variant-specific Surface Proteins (VSPs). By comparison, host-cell attached trophozoites up-regulated intracellular pathways for ubiquitination, reactive oxygen species (ROS) detoxification and production of pyridoxal phosphate (PLP). We reason that these results demonstrate early pathogenesis in Giardia involves two independent host-parasite interactions. Motile trophozoites respond to soluble secreted signals, which deter attachment and induce expression of virulence factors. Trophozoites attached to host cells, in contrast, respond by up-regulating intracellular pathways involved in clearance of ROS, thus anticipating the host defence response. PMID:26867958

  15. Induction of virulence factors in Giardia duodenalis independent of host attachment.

    PubMed

    Emery, Samantha J; Mirzaei, Mehdi; Vuong, Daniel; Pascovici, Dana; Chick, Joel M; Lacey, Ernest; Haynes, Paul A

    2016-01-01

    Giardia duodenalis is responsible for the majority of parasitic gastroenteritis in humans worldwide. Host-parasite interaction models in vitro provide insights into disease and virulence and help us to understand pathogenesis. Using HT-29 intestinal epithelial cells (IEC) as a model we have demonstrated that initial sensitisation by host secretions reduces proclivity for trophozoite attachment, while inducing virulence factors. Host soluble factors triggered up-regulation of membrane and secreted proteins, including Tenascins, Cathepsin-B precursor, cystatin, and numerous Variant-specific Surface Proteins (VSPs). By comparison, host-cell attached trophozoites up-regulated intracellular pathways for ubiquitination, reactive oxygen species (ROS) detoxification and production of pyridoxal phosphate (PLP). We reason that these results demonstrate early pathogenesis in Giardia involves two independent host-parasite interactions. Motile trophozoites respond to soluble secreted signals, which deter attachment and induce expression of virulence factors. Trophozoites attached to host cells, in contrast, respond by up-regulating intracellular pathways involved in clearance of ROS, thus anticipating the host defence response. PMID:26867958

  16. Additives

    NASA Technical Reports Server (NTRS)

    Smalheer, C. V.

    1973-01-01

    The chemistry of lubricant additives is discussed to show what the additives are chemically and what functions they perform in the lubrication of various kinds of equipment. Current theories regarding the mode of action of lubricant additives are presented. The additive groups discussed include the following: (1) detergents and dispersants, (2) corrosion inhibitors, (3) antioxidants, (4) viscosity index improvers, (5) pour point depressants, and (6) antifouling agents.

  17. Differential expression and interaction of host factors augment HIV-1 gene expression in neonatal mononuclear cells

    SciTech Connect

    Sundaravaradan, Vasudha; Mehta, Roshni; Harris, David T.; Zack, Jerome A.; Ahmad, Nafees

    2010-04-25

    We have previously shown a higher level of HIV-1 replication and gene expression in neonatal (cord) blood mononuclear cells (CBMC) compared with adult blood cells (PBMC), which could be due to differential expression of host factors. We performed the gene expression profile of CBMC and PBMC and found that 8013 genes were expressed at higher levels in CBMC than PBMC and 8028 genes in PBMC than CBMC, including 1181 and 1414 genes upregulated after HIV-1 infection in CBMC and PBMC, respectively. Several transcription factors (NF-kappaB, E2F, HAT-1, TFIIE, Cdk9, Cyclin T1), signal transducers (STAT3, STAT5A) and cytokines (IL-1beta, IL-6, IL-10) were upregulated in CBMC than PBMC, which are known to influence HIV-1 replication. In addition, a repressor of HIV-1 transcription, YY1, was down regulated in CBMC than PBMC and several matrix metalloproteinase (MMP-7, -12, -14) were significantly upregulated in HIV-1 infected CBMC than PBMC. Furthermore, we show that CBMC nuclear extracts interacted with a higher extent to HIV-1 LTR cis-acting sequences, including NF-kappaB, NFAT, AP1 and NF-IL6 compared with PBMC nuclear extracts and retroviral based short hairpin RNA (shRNA) for STAT3 and IL-6 down regulated their own and HIV-1 gene expression, signifying that these factors influenced differential HIV-1 gene expression in CBMC than PBMC.

  18. Genome-Wide Search for Host Association Factors during Ovine Progressive Pneumonia Virus Infection

    PubMed Central

    Quinn, Meghan; Xiang, Shi-Hua

    2016-01-01

    Ovine progressive pneumonia virus (OPPV) is an important virus that causes serious diseases in sheep and goats with a prevalence of 36% in the USA. Although OPPV was discovered more than half of a century ago, little is known about the infection and pathogenesis of this virus. In this report, we used RNA-seq technology to conduct a genome-wide probe for cellular factors that are associated with OPPV infection. A total of approximately 22,000 goat host genes were detected of which 657 were found to have been significantly up-regulated and 889 down-regulated at 12 hours post-infection. In addition to previously known restriction factors from other viral infections, a number of factors which may be specific for OPPV infection were uncovered. The data from this RNA-seq study will be helpful in our understanding of OPPV infection, and also for further study in the prevention and intervention of this viral disease. PMID:26950733

  19. Post-Transcriptional Control of LINE-1 Retrotransposition by Cellular Host Factors in Somatic Cells

    PubMed Central

    Pizarro, Javier G.; Cristofari, Gaël

    2016-01-01

    Long INterspersed Element-1 (LINE-1 or L1) retrotransposons form the only autonomously active family of transposable elements in humans. They are expressed and mobile in the germline, in embryonic stem cells and in the early embryo, but are silenced in most somatic tissues. Consistently, they play an important role in individual genome variations through insertional mutagenesis and sequence transduction, which occasionally lead to novel genetic diseases. In addition, they are reactivated in nearly half of the human epithelial cancers, contributing to tumor genome dynamics. The L1 element codes for two proteins, ORF1p and ORF2p, which are essential for its mobility. ORF1p is an RNA-binding protein with nucleic acid chaperone activity and ORF2p possesses endonuclease and reverse transcriptase activities. These proteins and the L1 RNA assemble into a ribonucleoprotein particle (L1 RNP), considered as the core of the retrotransposition machinery. The L1 RNP mediates the synthesis of new L1 copies upon cleavage of the target DNA and reverse transcription of the L1 RNA at the target site. The L1 element takes benefit of cellular host factors to complete its life cycle, however several cellular pathways also limit the cellular accumulation of L1 RNPs and their deleterious activities. Here, we review the known cellular host factors and pathways that regulate positively or negatively L1 retrotransposition at post-transcriptional level, in particular by interacting with the L1 machinery or L1 replication intermediates; and how they contribute to control L1 activity in somatic cells. PMID:27014690

  20. Role of viral and host factors in interferon based therapy of hepatitis C virus infection.

    PubMed

    Imran, Muhammad; Manzoor, Sobia; Ashraf, Javed; Khalid, Madiha; Tariq, Muqddas; Khaliq, Hafiza Madeha; Azam, Sikandar

    2013-01-01

    The current standard of care (SOC) for hepatitis C virus (HCV) infection is the combination of pegylated interferon (PEG-IFN), Ribavirin and protease inhibitor for HCV genotype 1. Nevertheless, this treatment is successful only in 70-80% of the patients. In addition, the treatment is not economical and is of immense physical burden for the subject. It has been established now, that virus-host interactions play a significant role in determining treatment outcomes. Therefore identifying biological markers that may predict the treatment response and hence treatment outcome would be useful. Both IFN and Ribavirin mainly act by modulating the immune system of the patient. Therefore, the treatment response is influenced by genetic variations of the human as well as the HCV genome. The goal of this review article is to summarize the impact of recent scientific advances in this area regarding the understanding of human and HCV genetic variations and their effect on treatment outcomes. Google scholar and PubMed have been used for literature research. Among the host factors, the most prominent associations are polymorphisms within the region of the interleukin 28B (IL28B) gene, but variations in other cytokine genes have also been linked with the treatment outcome. Among the viral factors, HCV genotypes are noteworthy. Moreover, for sustained virological responses (SVR), variations in core, p7, non-structural 2 (NS2), NS3 and NS5A genes are also important. However, all considered single nucleotide polymorphisms (SNPs) of IL28B and viral genotypes are the most important predictors for interferon based therapy of HCV infection. PMID:24079723

  1. Making Bunyaviruses Talk: Interrogation Tactics to Identify Host Factors Required for Infection

    PubMed Central

    Riblett, Amber M.; Doms, Robert W.

    2016-01-01

    The identification of host cellular genes that act as either proviral or antiviral factors has been aided by the development of an increasingly large number of high-throughput screening approaches. Here, we review recent advances in which these new technologies have been used to interrogate host genes for the ability to impact bunyavirus infection, both in terms of technical advances as well as a summary of biological insights gained from these studies. PMID:27187446

  2. A host cell membrane microdomain is a critical factor for organelle discharge by Toxoplasma gondii.

    PubMed

    Tahara, Michiru; Andrabi, Syed Bilal Ahmad; Matsubara, Ryuma; Aonuma, Hiroka; Nagamune, Kisaburo

    2016-10-01

    Host cell microdomains are involved in the attachment, entry, and replication of intracellular microbial pathogens. Entry into the host cell of Toxoplasma gondii and the subsequent survival of this protozoan parasite are tightly coupled with the proteins secreted from organelle called rhoptry. The rhoptry proteins are rapidly discharged into clusters of vesicles, called evacuoles, which are then delivered to parasitophorous vacuoles (PVs) or nucleus. In this study, we examined the roles of two host cell microdomain components, cholesterol and glycosylphosphatidylinositol (GPI), in evacuole formation. The acute depletion of cholesterol from the host cell plasma membrane blocked evacuole formation but not invasion. Whereas the lack of host cell GPI also altered evacuole formation but not invasion, instead inducing excess evacuole formation. The latter effect was not influenced by the evacuole-inhibiting effects of host cell cholesterol depletion, indicating the independent roles of host GPI and cholesterol in evacuole formation. In addition, the excess formation of evacuoles resulted in the enhanced recruitment of host mitochondria and endoplasmic reticulum to PVs, which in turn stimulated the growth of the parasite. PMID:27217289

  3. Host and microbiological factors related to dental caries development.

    PubMed

    De Soet, J J; van Gemert-Schriks, M C M; Laine, M L; van Amerongen, W E; Morré, S A; van Winkelhoff, A J

    2008-01-01

    Studies on dental caries suggest that in severe cases it may induce a systemic immune response. This occurs particularly when caries progresses into pulpal inflammation and results in abscess or fistula formation (AFF). We hypothesized that severe dental caries will affect the general health of children. The acute phase proteins alpha-1-acid glycoprotein (AGP), C-reactive protein (CRP) and the cytokine neopterin were chosen as parameters to monitor general health. Also, a polymorphism in the bacterial ligand CD14 (-260) was studied to investigate the relationship between genotype sensitivity for bacterial infections and AFF. In Suriname, children aged 6 years were recruited and enrolled into a dental care scheme, randomly assigned to 4 groups with different treatment strategies and monitored longitudinally. 348 children were included in the present study. Blood and saliva samples were taken at baseline and 1 year, and concentrations of serum AGP, CRP, neopterin, salivary Streptococcus mutans and CD14-260 C>T polymorphism were determined. There was no significant association between different treatment strategies and the serum parameters. Binary logistic regression analyses revealed a significant association between AFF as the outcome variable and the CD14 genotype and the concentrations of CRP and of neopterin as factors (p < 0.05). A significant negative association was found between the CD14-260 TT and AFF (p = 0.035, OR = 3.3) for the whole population. For children who had 4 or more carious lesions at baseline, the significance increased (p = 0.005, OR = 4.8), suggesting that the CD14-260 TT genotype was protective for AFF as a consequence of dental caries. PMID:18701824

  4. AP-42 ADDITIONS AND REVISIONS - TRANSPORTABILITY FACTORS FOR FUGITIVE DUST

    EPA Science Inventory

    The product is a table of factors, one for each county in the US, reflecting the portion of fugitive dust removed very close to the source via impaction on vegetation and similar mechanisms. Factors were based on land cover in area (county or grid cell) A praft final product was...

  5. Microbial Hub Taxa Link Host and Abiotic Factors to Plant Microbiome Variation.

    PubMed

    Agler, Matthew T; Ruhe, Jonas; Kroll, Samuel; Morhenn, Constanze; Kim, Sang-Tae; Weigel, Detlef; Kemen, Eric M

    2016-01-01

    Plant-associated microorganisms have been shown to critically affect host physiology and performance, suggesting that evolution and ecology of plants and animals can only be understood in a holobiont (host and its associated organisms) context. Host-associated microbial community structures are affected by abiotic and host factors, and increased attention is given to the role of the microbiome in interactions such as pathogen inhibition. However, little is known about how these factors act on the microbial community, and especially what role microbe-microbe interaction dynamics play. We have begun to address this knowledge gap for phyllosphere microbiomes of plants by simultaneously studying three major groups of Arabidopsis thaliana symbionts (bacteria, fungi and oomycetes) using a systems biology approach. We evaluated multiple potential factors of microbial community control: we sampled various wild A. thaliana populations at different times, performed field plantings with different host genotypes, and implemented successive host colonization experiments under lab conditions where abiotic factors, host genotype, and pathogen colonization was manipulated. Our results indicate that both abiotic factors and host genotype interact to affect plant colonization by all three groups of microbes. Considering microbe-microbe interactions, however, uncovered a network of interkingdom interactions with significant contributions to community structure. As in other scale-free networks, a small number of taxa, which we call microbial "hubs," are strongly interconnected and have a severe effect on communities. By documenting these microbe-microbe interactions, we uncover an important mechanism explaining how abiotic factors and host genotypic signatures control microbial communities. In short, they act directly on "hub" microbes, which, via microbe-microbe interactions, transmit the effects to the microbial community. We analyzed two "hub" microbes (the obligate biotrophic

  6. Microbial Hub Taxa Link Host and Abiotic Factors to Plant Microbiome Variation

    PubMed Central

    Agler, Matthew T.; Ruhe, Jonas; Kroll, Samuel; Morhenn, Constanze; Kim, Sang-Tae; Weigel, Detlef; Kemen, Eric M.

    2016-01-01

    Plant-associated microorganisms have been shown to critically affect host physiology and performance, suggesting that evolution and ecology of plants and animals can only be understood in a holobiont (host and its associated organisms) context. Host-associated microbial community structures are affected by abiotic and host factors, and increased attention is given to the role of the microbiome in interactions such as pathogen inhibition. However, little is known about how these factors act on the microbial community, and especially what role microbe–microbe interaction dynamics play. We have begun to address this knowledge gap for phyllosphere microbiomes of plants by simultaneously studying three major groups of Arabidopsis thaliana symbionts (bacteria, fungi and oomycetes) using a systems biology approach. We evaluated multiple potential factors of microbial community control: we sampled various wild A. thaliana populations at different times, performed field plantings with different host genotypes, and implemented successive host colonization experiments under lab conditions where abiotic factors, host genotype, and pathogen colonization was manipulated. Our results indicate that both abiotic factors and host genotype interact to affect plant colonization by all three groups of microbes. Considering microbe–microbe interactions, however, uncovered a network of interkingdom interactions with significant contributions to community structure. As in other scale-free networks, a small number of taxa, which we call microbial “hubs,” are strongly interconnected and have a severe effect on communities. By documenting these microbe–microbe interactions, we uncover an important mechanism explaining how abiotic factors and host genotypic signatures control microbial communities. In short, they act directly on “hub” microbes, which, via microbe–microbe interactions, transmit the effects to the microbial community. We analyzed two “hub” microbes (the

  7. Trypanosoma cruzi-induced host immune system dysfunction: a rationale for parasite immunosuppressive factor(s) encoding gene targeting

    PubMed Central

    2001-01-01

    An intense suppression of T cell proliferation to mitogens and to antigens is observed in a large number of parasitic infections. The impairment of T cell proliferation also occurred during the acute phase of Chagas' disease, caused by the intracellular protozoan parasite Trypanosoma cruzi. A wealth of evidence has accumulated that illustrates the ability of T. cruzi released molecules to influence directly a variety of diverse immunological functions. In this paper, we review the data concerning the immunoregulatory effects of T. cruzi Tc24 (a B cell activator antigen) and Tc52 (an immunosuppressive protein) released molecules on the host immune system. The gene targeting approach developed to further explore the biological function(s) of Tc52 molecule, revealed interesting unexpected functional properties. Indeed, in addition to its immunusuppressive activity a direct or indirect involvement of Tc52 gene product alone or in combination with other cellular components in T. cruzi differentiation control mechanisms have been evidenced. Moreover, targeted Tc52 replacement allowed the obtention of parasite mutants exhibiting low virulence in vitro and in vivo. Thus, the generation of a complete deficiency state of virulence factors by gene targeting should provide a means to assess the importance of these factors in the pathophysiological processes and disease progression. It is hoped that such approaches might allow rational design of tools to control T. cruzi infections. PMID:12488621

  8. Tandem immunoprecipitation approach to identify HIV-1 Gag associated host factors.

    PubMed

    Gao, Wei; Li, Min; Zhang, Jingxin

    2014-07-01

    HIV-1 Gag by itself is able to assemble and release from host cells and thus serves as a simplified model to identify host factors involved in this stage of the HIV-1 life cycle. In this study, a tandem immunoprecipitation approach is taken to immunoprecipitate Gag-interacting host proteins from transfected 293T cells. It is demonstrated that with the tandem immunoprecipitation method Gag-interacting host factors can be precipitated more efficiently than by single-step immunoprecipitation. Gag proteins are found to interact with multiple RNA-binding proteins such as hnRNPs, nucleolin, EF1a and ribosomal proteins. Such interactions are mediated by cellular RNAs and the Gag Nuclear Capsid (NC) domain. Deletion of the NC domain results in removal of most of the RNA-binding proteins, as well as a reduction of the Gag releasing capability, which can be restored by replacing the deleted NC domain with another multimerization motif. Importantly, interactions between Gag and host factors are relevant functionally, as evidenced by significantly increased nucleolin protein in the cytoplasm where it is recruited into the Gag complex, and enhanced Gag release when nucleolin is over-expressed. PMID:24690621

  9. Industrial production of clotting factors: Challenges of expression, and choice of host cells.

    PubMed

    Kumar, Sampath R

    2015-07-01

    The development of recombinant forms of blood coagulation factors as safer alternatives to plasma derived factors marked a major advance in the treatment of common coagulation disorders. These are complex proteins, mostly enzymes or co-enzymes, involving multiple post-translational modifications, and therefore are difficult to express. This article reviews the nature of the expression challenges for the industrial production of these factors, vis-à-vis the translational and post-translational bottlenecks, as well as the choice of host cell lines for high-fidelity production. For achieving high productivities of vitamin K dependent proteins, which include factors II (prothrombin), VII, IX and X, and protein C, host cell limitation of γ-glutamyl carboxylation is a major bottleneck. Despite progress in addressing this, involvement of yet unidentified protein(s) impedes a complete cell engineering solution. Human factor VIII expresses at very low levels due to limitations at several steps in the protein secretion pathway. Protein and cell engineering, vector improvement and alternate host cells promise improvement in the productivity. Production of Von Willebrand factor is constrained by its large size, complex structure, and the need for extensive glycosylation and disulfide-bonded oligomerization. All the licensed therapeutic factors are produced in CHO, BHK or HEK293 cells. While HEK293 is a recent adoption, BHK cells appear to be disfavored. PMID:26099845

  10. The Role of Viral, Host, and Secondary Bacterial Factors in Influenza Pathogenesis

    PubMed Central

    Kash, John C.; Taubenberger, Jeffery K.

    2016-01-01

    Influenza A virus infections in humans generally cause self-limited infections, but can result in severe disease, secondary bacterial pneumonias, and death. Influenza viruses can replicate in epithelial cells throughout the respiratory tree and can cause tracheitis, bronchitis, bronchiolitis, diffuse alveolar damage with pulmonary edema and hemorrhage, and interstitial and airspace inflammation. The mechanisms by which influenza infections result in enhanced disease, including development of pneumonia and acute respiratory distress, are multifactorial, involving host, viral, and bacterial factors. Host factors that enhance risk of severe influenza disease include underlying comorbidities, such as cardiac and respiratory disease, immunosuppression, and pregnancy. Viral parameters enhancing disease risk include polymerase mutations associated with host switch and adaptation, viral proteins that modulate immune and antiviral responses, and virulence factors that increase disease severity, which can be especially prominent in pandemic viruses and some zoonotic influenza viruses causing human infections. Influenza viral infections result in damage to the respiratory epithelium that facilitates secondary infection with common bacterial pneumopathogens and can lead to secondary bacterial pneumonias that greatly contribute to respiratory distress, enhanced morbidity, and death. Understanding the molecular mechanisms by which influenza and secondary bacterial infections, coupled with the role of host risk factors, contribute to enhanced morbidity and mortality is essential to develop better therapeutic strategies to treat severe influenza. PMID:25747532

  11. Distinct immunoregulatory properties of macrophage migration inhibitory factors encoded by Eimeria parasites and their chicken host

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that plays an important role in host defense against a variety of microorganisms including protozoan parasites. Interestingly, some microbial pathogens also express a MIF-like protein, although its role in disease pathogenesi...

  12. Host factors in retroviral integration and the selection of integration target sites

    PubMed Central

    Craigie, Robert; Bushman, Frederic D.

    2015-01-01

    In order to replicate, a retrovirus must integrate a DNA copy of the viral RNA genome into a chromosome of the host cell. The study of retroviral integration has advanced considerably in the last few years. Here we focus on host factor interactions and the linked area of integration targeting. Genome-wide screens for cellular factors affecting HIV replication have identified a series of host cell proteins that may mediate subcellular trafficking of integration complexes, nuclear import, and integration target site selection. The cell transcriptional co-activator protein LEDGF/p75 has been identified as a tethering factor important for HIV integration, and recently, BET proteins (Brd2, 4, and 4) have been identified as tethering factors for the gammaretroviruses. A new class of HIV inhibitors has been developed targeting the HIV-1 IN-LEDGF binding site, though surprisingly these inhibitors appear to block assembly late during replication and do not act at the integration step. Going forward, genome-wide studies of HIV-host interactions offer many new starting points to investigate HIV replication and identify potential new inhibitor targets. PMID:26104434

  13. Host proteins interacting with the Moloney murine leukemia virus integrase: Multiple transcriptional regulators and chromatin binding factors

    PubMed Central

    Studamire, Barbara; Goff, Stephen P

    2008-01-01

    Background A critical step for retroviral replication is the stable integration of the provirus into the genome of its host. The viral integrase protein is key in this essential step of the retroviral life cycle. Although the basic mechanism of integration by mammalian retroviruses has been well characterized, the factors determining how viral integration events are targeted to particular regions of the genome or to regions of a particular DNA structure remain poorly defined. Significant questions remain regarding the influence of host proteins on the selection of target sites, on the repair of integration intermediates, and on the efficiency of integration. Results We describe the results of a yeast two-hybrid screen using Moloney murine leukemia virus integrase as bait to screen murine cDNA libraries for host proteins that interact with the integrase. We identified 27 proteins that interacted with different integrase fusion proteins. The identified proteins include chromatin remodeling, DNA repair and transcription factors (13 proteins); translational regulation factors, helicases, splicing factors and other RNA binding proteins (10 proteins); and transporters or miscellaneous factors (4 proteins). We confirmed the interaction of these proteins with integrase by testing them in the context of other yeast strains with GAL4-DNA binding domain-integrase fusions, and by in vitro binding assays between recombinant proteins. Subsequent analyses revealed that a number of the proteins identified as Mo-MLV integrase interactors also interact with HIV-1 integrase both in yeast and in vitro. Conclusion We identify several proteins interacting directly with both MoMLV and HIV-1 integrases that may be common to the integration reaction pathways of both viruses. Many of the proteins identified in the screen are logical interaction partners for integrase, and the validity of a number of the interactions are supported by other studies. In addition, we observe that some of the

  14. Role of virulence factors on host inflammatory response induced by diarrheagenic Escherichia coli pathotypes.

    PubMed

    Sanchez-Villamil, Javier; Navarro-Garcia, Fernando

    2015-01-01

    Pathogens are able to breach the intestinal barrier, and different bacterial species can display different abilities to colonize hosts and induce inflammation. Inflammatory response studies induced by enteropathogens as Escherichia coli are interesting since it has acquired diverse genetic mobile elements, leading to different E. coli pathotypes. Diarrheagenic E. coli secrete toxins, effectors and virulence factors that exploit the host cell functions to facilitate the bacterial colonization. Many bacterial proteins are delivered to the host cell for subverting the inflammatory response. Hereby, we have highlighted the specific processes used by E. coli pathotypes, by that subvert the inflammatory pathways. These mechanisms include an arrangement of pro- and anti-inflammatory responses to favor the appropriate environmental niche for the bacterial survival and growth. PMID:26059623

  15. Host Transcription Factors in the Immediate Pro-Inflammatory Response to the Parasitic Mite Psoroptes ovis

    PubMed Central

    Burgess, Stewart T. G.; McNeilly, Tom N.; Watkins, Craig A.; Nisbet, Alasdair J.; Huntley, John F.

    2011-01-01

    Background Sheep scab, caused by infestation with the ectoparasitic mite Psoroptes ovis, results in the rapid development of cutaneous inflammation and leads to the crusted skin lesions characteristic of the disease. We described previously the global host transcriptional response to infestation with P. ovis, elucidating elements of the inflammatory processes which lead to the development of a rapid and profound immune response. However, the mechanisms by which this response is instigated remain unclear. To identify novel methods of intervention a better understanding of the early events involved in triggering the immune response is essential. The objective of this study was to gain a clearer understanding of the mechanisms and signaling pathways involved in the instigation of the immediate pro-inflammatory response. Results Through a combination of transcription factor binding site enrichment and pathway analysis we identified key roles for a number of transcription factors in the instigation of cutaneous inflammation. In particular, defined roles were elucidated for the transcription factors NF-kB and AP-1 in the orchestration of the early pro-inflammatory response, with these factors being implicated in the activation of a suite of inflammatory mediators. Conclusions Interrogation of the host temporal response to P. ovis infestation has enabled the further identification of the mechanisms underlying the development of the immediate host pro-inflammatory response. This response involves key regulatory roles for the transcription factors NF-kB and AP-1. Pathway analysis demonstrated that the activation of these transcription factors may be triggered following a host LPS-type response, potentially involving TLR4-signalling and also lead to the intriguing possibility that this could be triggered by a P. ovis allergen. PMID:21915322

  16. Quantitative Proteomics Identifies Serum Response Factor Binding Protein 1 as a Host Factor for Hepatitis C Virus Entry.

    PubMed

    Gerold, Gisa; Meissner, Felix; Bruening, Janina; Welsch, Kathrin; Perin, Paula M; Baumert, Thomas F; Vondran, Florian W; Kaderali, Lars; Marcotrigiano, Joseph; Khan, Abdul G; Mann, Matthias; Rice, Charles M; Pietschmann, Thomas

    2015-08-01

    Hepatitis C virus (HCV) enters human hepatocytes through a multistep mechanism involving, among other host proteins, the virus receptor CD81. How CD81 governs HCV entry is poorly characterized, and CD81 protein interactions after virus binding remain elusive. We have developed a quantitative proteomics protocol to identify HCV-triggered CD81 interactions and found 26 dynamic binding partners. At least six of these proteins promote HCV infection, as indicated by RNAi. We further characterized serum response factor binding protein 1 (SRFBP1), which is recruited to CD81 during HCV uptake and supports HCV infection in hepatoma cells and primary human hepatocytes. SRFBP1 facilitates host cell penetration by all seven HCV genotypes, but not of vesicular stomatitis virus and human coronavirus. Thus, SRFBP1 is an HCV-specific, pan-genotypic host entry factor. These results demonstrate the use of quantitative proteomics to elucidate pathogen entry and underscore the importance of host protein-protein interactions during HCV invasion. PMID:26212323

  17. Novel Burkholderia mallei Virulence Factors Linked to Specific Host-Pathogen Protein Interactions*

    PubMed Central

    Memišević, Vesna; Zavaljevski, Nela; Pieper, Rembert; Rajagopala, Seesandra V.; Kwon, Keehwan; Townsend, Katherine; Yu, Chenggang; Yu, Xueping; DeShazer, David; Reifman, Jaques; Wallqvist, Anders

    2013-01-01

    Burkholderia mallei is an infectious intracellular pathogen whose virulence and resistance to antibiotics makes it a potential bioterrorism agent. Given its genetic origin as a commensal soil organism, it is equipped with an extensive and varied set of adapted mechanisms to cope with and modulate host-cell environments. One essential virulence mechanism constitutes the specialized secretion systems that are designed to penetrate host-cell membranes and insert pathogen proteins directly into the host cell's cytosol. However, the secretion systems' proteins and, in particular, their host targets are largely uncharacterized. Here, we used a combined in silico, in vitro, and in vivo approach to identify B. mallei proteins required for pathogenicity. We used bioinformatics tools, including orthology detection and ab initio predictions of secretion system proteins, as well as published experimental Burkholderia data to initially select a small number of proteins as putative virulence factors. We then used yeast two-hybrid assays against normalized whole human and whole murine proteome libraries to detect and identify interactions among each of these bacterial proteins and host proteins. Analysis of such interactions provided both verification of known virulence factors and identification of three new putative virulence proteins. We successfully created insertion mutants for each of these three proteins using the virulent B. mallei ATCC 23344 strain. We exposed BALB/c mice to mutant strains and the wild-type strain in an aerosol challenge model using lethal B. mallei doses. In each set of experiments, mice exposed to mutant strains survived for the 21-day duration of the experiment, whereas mice exposed to the wild-type strain rapidly died. Given their in vivo role in pathogenicity, and based on the yeast two-hybrid interaction data, these results point to the importance of these pathogen proteins in modulating host ubiquitination pathways, phagosomal escape, and actin

  18. Effects of Host Plant Factors on the Bacterial Communities Associated with Two Whitefly Sibling Species

    PubMed Central

    Su, Ming-Ming; Guo, Lei; Tao, Yun-Li; Zhang, You-Jun; Wan, Fang-Hao; Chu, Dong

    2016-01-01

    Background Although discrepancy in the specific traits and ecological characteristics of Bemisia tabaci between species are partially attributed to the B. tabaci-associated bacteria, the factors that affect the diversity of B. tabaci-associated bacteria are not well-understood. We used the metagenomic approach to characterize the B. tabaci-associated bacterial community because the approach is an effective tool to identify the bacteria. Methodology and Results To investigate the effects of the host plant and a virus, tomato yellow leaf curl virus (TYLCV), on the bacterial communities of B. tabaci sibling species B and Q, we analyzed the bacterial communities associated with whitefly B and Q collected from healthy cotton, healthy tomato, and TYLCV-infected tomato. The analysis used miseq-based sequencing of a variable region of the bacterial 16S rDNA gene. For the bacteria associated with B. tabaci, we found that the influence of the host plant species was greater than that of the whitefly cryptic species. With further analysis of host plants infected with the TYLCV, the virus had no significant effects on the B. tabaci-associated bacterial community. Conclusions The effects of different plant hosts and TYLCV-infection on the diversity of B. tabaci-associated bacterial communities were successfully analyzed in this study. To explain why B. tabaci sibling species with different host ranges differ in performance, the analysis of the bacterial community may be essential to the explanation. PMID:27008327

  19. Novel insights into human respiratory syncytial virus-host factor interactions through integrated proteomics and transcriptomics analysis

    PubMed Central

    Dapat, Clyde; Oshitani, Hitoshi

    2016-01-01

    ABSTRACT The lack of vaccine and limited antiviral options against respiratory syncytial virus (RSV) highlights the need for novel therapeutic strategies. One alternative is to develop drugs that target host factors required for viral replication. Several microarray and proteomics studies had been published to identify possible host factors that are affected during RSV replication. In order to obtain a comprehensive understanding of RSV-host interaction, we integrated available proteome and transcriptome datasets and used it to construct a virus-host interaction network. Then, we interrogated the network to identify host factors that are targeted by the virus and we searched for drugs from the DrugBank database that interact with these host factors, which may have potential applications in repositioning for future treatment options of RSV infection. PMID:26760927

  20. Genetic and immunological host factors associated with susceptibility to HIV-1 infection.

    PubMed

    Buchacz, K A; Wilkinson, D A; Krowka, J F; Koup, R A; Padian, N S

    1998-01-01

    The probability of HIV transmission depends on the interplay of many different factors related to infectiousness of the HIV-infected partner, susceptibility of the HIV-uninfected partner, and biological characteristics of HIV strains. Here, we review recent studies of host immunological and genetic factors which may affect susceptibility to HIV-1 infection. These factors are summarized in Table 1. We propose how to explore biological correlates of susceptibility to HIV-1 infection in epidemiological studies, discuss the strengths and limitations of this research, and address the implications for public health. PMID:9632989

  1. EHFPI: a database and analysis resource of essential host factors for pathogenic infection.

    PubMed

    Liu, Yang; Xie, Dafei; Han, Lu; Bai, Hui; Li, Fei; Wang, Shengqi; Bo, Xiaochen

    2015-01-01

    High-throughput screening and computational technology has greatly changed the face of microbiology in better understanding pathogen-host interactions. Genome-wide RNA interference (RNAi) screens have given rise to a new class of host genes designated as Essential Host Factors (EHFs), whose knockdown effects significantly influence pathogenic infections. Therefore, we present the first release of a manually-curated bioinformatics database and analysis resource EHFPI (Essential Host Factors for Pathogenic Infection, http://biotech.bmi.ac.cn/ehfpi). EHFPI captures detailed article, screen, pathogen and phenotype annotation information for a total of 4634 EHF genes of 25 clinically important pathogenic species. Notably, EHFPI also provides six powerful and data-integrative analysis tools, i.e. EHF Overlap Analysis, EHF-pathogen Network Analysis, Gene Enrichment Analysis, Pathogen Interacting Proteins (PIPs) Analysis, Drug Target Analysis and GWAS Candidate Gene Analysis, which advance the comprehensive understanding of the biological roles of EHF genes, as in diverse perspectives of protein-protein interaction network, drug targets and diseases/traits. The EHFPI web interface provides appropriate tools that allow efficient query of EHF data and visualization of custom-made analysis results. EHFPI data and tools shall keep available without charge and serve the microbiology, biomedicine and pharmaceutics research communities, to finally facilitate the development of diagnostics, prophylactics and therapeutics for human pathogens. PMID:25414353

  2. EHFPI: a database and analysis resource of essential host factors for pathogenic infection

    PubMed Central

    Liu, Yang; Xie, Dafei; Han, Lu; Bai, Hui; Li, Fei; Wang, Shengqi; Bo, Xiaochen

    2015-01-01

    High-throughput screening and computational technology has greatly changed the face of microbiology in better understanding pathogen–host interactions. Genome-wide RNA interference (RNAi) screens have given rise to a new class of host genes designated as Essential Host Factors (EHFs), whose knockdown effects significantly influence pathogenic infections. Therefore, we present the first release of a manually-curated bioinformatics database and analysis resource EHFPI (Essential Host Factors for Pathogenic Infection, http://biotech.bmi.ac.cn/ehfpi). EHFPI captures detailed article, screen, pathogen and phenotype annotation information for a total of 4634 EHF genes of 25 clinically important pathogenic species. Notably, EHFPI also provides six powerful and data-integrative analysis tools, i.e. EHF Overlap Analysis, EHF-pathogen Network Analysis, Gene Enrichment Analysis, Pathogen Interacting Proteins (PIPs) Analysis, Drug Target Analysis and GWAS Candidate Gene Analysis, which advance the comprehensive understanding of the biological roles of EHF genes, as in diverse perspectives of protein–protein interaction network, drug targets and diseases/traits. The EHFPI web interface provides appropriate tools that allow efficient query of EHF data and visualization of custom-made analysis results. EHFPI data and tools shall keep available without charge and serve the microbiology, biomedicine and pharmaceutics research communities, to finally facilitate the development of diagnostics, prophylactics and therapeutics for human pathogens. PMID:25414353

  3. Metallothionein differentially affects the host response to Listeria infection both with and without an additional stress from cold-restraint.

    PubMed

    Emeny, Rebecca T; Kasten-Jolly, Jane; Mondal, Tapan; Lynes, Michael A; Lawrence, David A

    2015-11-01

    Acute stress alters anti-bacterial defenses, but the neuroimmunological mechanisms underlying this association are not yet well understood. Metallothionein (MT), a cysteine-rich protein, is a stress response protein that is induced by a variety of chemical, biological, and psychological stressors, and MT has been shown to influence immune activities. We investigated MT's role in the management of anti-bacterial responses that occur during stress, using a C57BL/6 (B6) strain that has targeted disruptions of the Mt1 and Mt2 genes (B6-MTKO), and a B6 strain that has additional copies of Mt (B6-MTTGN). The well-characterized listeriosis model was used to examine immune mechanisms that are altered by a 1-h stress treatment (cold-restraint, CR) administered just prior to bacterial infection. Intriguingly, MT gene doses both greater and lower than that of wild-type (WT) B6 mice were associated with improved host defenses against Listeria monocytogenes (LM). This augmented protection was diminished by CR stress in the MTKO mice, but transgenic mice with additional MT copies had no CR stress-induced increase in their listerial burden. During the transition from innate to adaptive immunity, on day 3 after infection, oxidative burst and apoptosis were assessed by flow cytometric methods, and cytokine transcription was measured by real-time quantitative PCR. MT gene expression and CR-stress affected the expression of IL-6 and TNFα. Additionally, these genetic and environmental modulations altered the generation of ROS responses as well as the number of apoptotic cells in livers and spleens. Although the level of MT altered the listerial response, MT expression was equally elevated by listerial infection with or without CR stress. These results indicate the ability of MT to regulate immune response mechanisms and demonstrate that increased amounts of MT can eliminate the immunosuppression induced by CR. PMID:26267326

  4. CTXϕ: Exploring new alternatives in host factor-mediated filamentous phage replications.

    PubMed

    Martínez, Eriel; Campos-Gómez, Javier; Barre, François-Xavier

    2016-01-01

    For a long time Ff phages from Escherichia coli provided the majority of the knowledge about the rolling circle replication mechanism of filamentous phages. Host factors involved in coliphages replication have been fully identified. Based on these studies, the function of Rep protein as the accessory helicase directly implicated in filamentous phage replication was considered a paradigm. We recently reported that the replication of some filamentous phages from Vibrio cholerae, including the cholera toxin phage CTXϕ, depended on the accessory helicase UvrD instead of Rep. We also identified HU protein as one of the host factors involved in CTXϕ and VGJϕ replication. The requirement of UvrD and HU for rolling circle replication was previously reported in some family of plasmids but had no precedent in filamentous phages. Here, we enrich the discussion of our results and present new preliminary data highlighting remarkable divergence in the lifestyle of filamentous phages. PMID:27607139

  5. Functional genomics approach for the identification of human host factors supporting dengue viral propagation

    PubMed Central

    Barrows, Nicholas J.; Jamison, Sharon F.; Bradrick, Shelton S.; Le Sommer, Caroline; Kim, So Young; Pearson, James; Garcia-Blanco, Mariano A.

    2014-01-01

    Dengue virus (DENV) is endemic throughout tropical regions around the world and there are no approved treatments or anti-transmission agents currently available. Consequently, there exists an enormous unmet need to treat the human diseases caused by DENV and block viral transmission by the mosquito vector. RNAi screening represents an efficient method to expand the pool of known host factors that could become viable targets for treatments or provide rationale to consider available drugs as anti-DENV treatments. We developed a high throughput siRNA-based screening protocol that can identify human DENV host factors. The protocol herein describes the materials and the procedures necessary to screen a human cell line in order to identify genes which are either necessary for or restrict DENV propagation at any stage in the viral life cycle. PMID:24696344

  6. Bioinformatic identification of Mycobacterium tuberculosis proteins likely to target host cell mitochondria: virulence factors?

    PubMed Central

    2012-01-01

    Background M. tuberculosis infection either induces or inhibits host cell death, depending on the bacterial strain and the cell microenvironment. There is evidence suggesting a role for mitochondria in these processes. On the other hand, it has been shown that several bacterial proteins are able to target mitochondria, playing a critical role in bacterial pathogenesis and modulation of cell death. However, mycobacteria–derived proteins able to target host cell mitochondria are less studied. Results A bioinformaic analysis based on available genomic sequences of the common laboratory virulent reference strain Mycobacterium tuberculosis H37Rv, the avirulent strain H37Ra, the clinical isolate CDC1551, and M. bovis BCG Pasteur strain 1173P2, as well as of suitable bioinformatic tools (MitoProt II, PSORT II, and SignalP) for the in silico search for proteins likely to be secreted by mycobacteria that could target host cell mitochondria, showed that at least 19 M. tuberculosis proteins could possibly target host cell mitochondria. We experimentally tested this bioinformatic prediction on four M. tuberculosis recombinant proteins chosen from this list of 19 proteins (p27, PE_PGRS1, PE_PGRS33, and MT_1866). Confocal microscopy analyses showed that p27, and PE_PGRS33 proteins colocalize with mitochondria. Conclusions Based on the bioinformatic analysis of whole M. tuberculosis genome sequences, we propose that at least 19 out of 4,246 M. tuberculosis predicted proteins would be able to target host cell mitochondria and, in turn, control mitochondrial physiology. Interestingly, such a list of 19 proteins includes five members of a mycobacteria specific family of proteins (PE/PE_PGRS) thought to be virulence factors, and p27, a well known virulence factor. P27, and PE_PGRS33 proteins experimentally showed to target mitochondria in J774 cells. Our results suggest a link between mitochondrial targeting of M. tuberculosis proteins and virulence. PMID:23259719

  7. A Growth Initiation Factor for Host-Independent Derivatives of Bdellovibrio bacteriovorus

    PubMed Central

    Ishiguro, Edward E.

    1973-01-01

    Host-independent (H-I) derivatives of Bdellovibrio bacteriovorus 109 Davis could not be isolated when concentrated suspensions of host-dependent (H-D) cultures, washed free of spent medium, were plated on host-free media. However, H-I colonies did appear when spent broth was incorporated into the isolation medium, indicating the presence of a factor in the spent medium essential for the growth of H-I cells. This growth factor (GIF) was also present in cell-free extracts of Escherichia coli and a variety of other microorganisms including H-D and H-I derivatives of strain 109 Davis. GIF was heat stable, non-dialyzable, and present in both soluble and particulate fractions of extracts. Heating of extracts at 70 C for 10 min resulted in 10- to 40-fold stimulation in GIF activity, and evidence for a heat-labile inhibitor was obtained. Colonies appearing on host-free medium in these experiments were shown to be those of typical H-I derivatives by isolation and subsequent host-independent cultivation of these organisms. GIF was a conditional requirement dependent on age and size of inoculum for all H-I derivatives characterized. Although GIF stimulated the growth of washed exponential phase cells transferred to fresh medium, it was not essential for growth. However, it was essential for the initiation of growth of washed stationary phase cells from small inocula transferred to fresh medium. It is proposed that GIF is required to initiate growth of metabolically quiescent cells. Images PMID:4197902

  8. Bacterial factors exploit eukaryotic Rho GTPase signaling cascades to promote invasion and proliferation within their host

    PubMed Central

    Popoff, Michel R

    2014-01-01

    Actin cytoskeleton is a main target of many bacterial pathogens. Among the multiple regulation steps of the actin cytoskeleton, bacterial factors interact preferentially with RhoGTPases. Pathogens secrete either toxins which diffuse in the surrounding environment, or directly inject virulence factors into target cells. Bacterial toxins, which interfere with RhoGTPases, and to some extent with RasGTPases, catalyze a covalent modification (ADPribosylation, glucosylation, deamidation, adenylation, proteolysis) blocking these molecules in their active or inactive state, resulting in alteration of epithelial and/or endothelial barriers, which contributes to dissemination of bacteria in the host. Injected bacterial virulence factors preferentially manipulate the RhoGTPase signaling cascade by mimicry of eukaryotic regulatory proteins leading to local actin cytoskeleton rearrangement, which mediates bacterial entry into host cells or in contrast escape to phagocytosis and immune defense. Invasive bacteria can also manipulate RhoGTPase signaling through recognition and stimulation of cell surface receptor(s). Changes in RhoGTPase activation state is sensed by the innate immunity pathways and allows the host cell to adapt an appropriate defense response. PMID:25203748

  9. Genetic and environmental factors affecting host response to drugs and other chemical compounds in our environment.

    PubMed Central

    Vesell, E S; Passananti, G T

    1977-01-01

    Compared to laboratory animals, humans are extremely heterogenous with respect to the many factors that can influence the distribution and biological effects of toxic chemicals. This heterogeneity can prevent an accurate assessment of the impact of a particular toxic compound on the health of an individual subject. Some of the factors that can significantly modify the host response to certain drugs, which serve in this review as a model for environmental chemicals, are enumerated and discussed. Although the mechanisms by which many of these factors modify the biological effects of certain environmental chemicals and drugs have been determined in some cases, better definition of the nature of interactions between these factors and environmental chemicals in a particular individual is required at a biochemical and molecular level. Recommendations are offered for the further development of our knowledge concerning interactions between environmental chemicals and such factors in a particular individual. PMID:598349

  10. Host Factors and Biomarkers Associated with Poor Outcomes in Adults with Invasive Pneumococcal Disease

    PubMed Central

    Hanada, Shigeo; Iwata, Satoshi; Kishi, Kazuma; Morozumi, Miyuki; Chiba, Naoko; Wajima, Takeaki; Takata, Misako; Ubukata, Kimiko

    2016-01-01

    Background Invasive pneumococcal disease (IPD) causes considerable morbidity and mortality. We aimed to identify host factors and biomarkers associated with poor outcomes in adult patients with IPD in Japan, which has a rapidly-aging population. Methods In a large-scale surveillance study of 506 Japanese adults with IPD, we investigated the role of host factors, disease severity, biomarkers based on clinical laboratory data, treatment regimens, and bacterial factors on 28-day mortality. Results Overall mortality was 24.1%, and the mortality rate increased from 10.0% in patients aged ˂50 years to 33.1% in patients aged ≥80 years. Disease severity also increased 28-day mortality, from 12.5% among patients with bacteraemia without sepsis to 35.0% in patients with severe sepsis and 56.9% with septic shock. The death rate within 48 hours after admission was high at 54.9%. Risk factors for mortality identified by multivariate analysis were as follows: white blood cell (WBC) count <4000 cells/μL (odds ratio [OR], 6.9; 95% confidence interval [CI], 3.7–12.8, p < .001); age ≥80 years (OR, 6.5; 95% CI, 2.0–21.6, p = .002); serum creatinine ≥2.0 mg/dL (OR, 4.5; 95% CI, 2.5–8.1, p < .001); underlying liver disease (OR, 3.5; 95% CI, 1.6–7.8, p = .002); mechanical ventilation (OR, 3.0; 95% CI, 1.7–5.6, p < .001); and lactate dehydrogenase ≥300 IU/L (OR, 2.4; 95% CI, 1.4–4.0, p = .001). Pneumococcal serotype and drug resistance were not associated with poor outcomes. Conclusions Host factors, disease severity, and biomarkers, especially WBC counts and serum creatinine, were more important determinants of mortality than bacterial factors. PMID:26815915

  11. Energy transfer between a nanosystem and its host fluid: A multiscale factorization approach

    SciTech Connect

    Sereda, Yuriy V.; Espinosa-Duran, John M.; Ortoleva, Peter J.

    2014-02-21

    Energy transfer between a macromolecule or supramolecular assembly and a host medium is considered from the perspective of Newton's equations and Lie-Trotter factorization. The development starts by demonstrating that the energy of the molecule evolves slowly relative to the time scale of atomic collisions-vibrations. The energy is envisioned to be a coarse-grained variable that coevolves with the rapidly fluctuating atomistic degrees of freedom. Lie-Trotter factorization is shown to be a natural framework for expressing this coevolution. A mathematical formalism and workflow for efficient multiscale simulation of energy transfer is presented. Lactoferrin and human papilloma virus capsid-like structure are used for validation.

  12. Energy transfer between a nanosystem and its host fluid: A multiscale factorization approach

    NASA Astrophysics Data System (ADS)

    Sereda, Yuriy V.; Espinosa-Duran, John M.; Ortoleva, Peter J.

    2014-02-01

    Energy transfer between a macromolecule or supramolecular assembly and a host medium is considered from the perspective of Newton's equations and Lie-Trotter factorization. The development starts by demonstrating that the energy of the molecule evolves slowly relative to the time scale of atomic collisions-vibrations. The energy is envisioned to be a coarse-grained variable that coevolves with the rapidly fluctuating atomistic degrees of freedom. Lie-Trotter factorization is shown to be a natural framework for expressing this coevolution. A mathematical formalism and workflow for efficient multiscale simulation of energy transfer is presented. Lactoferrin and human papilloma virus capsid-like structure are used for validation.

  13. 21 CFR 1311.115 - Additional requirements for two-factor authentication.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Additional requirements for two-factor... Additional requirements for two-factor authentication. (a) To sign a controlled substance prescription, the... authentication protocol that uses two of the following three factors: (1) Something only the practitioner...

  14. Host co-factors of the retrovirus-like transposon Ty1

    PubMed Central

    2012-01-01

    Background Long-terminal repeat (LTR) retrotransposons have complex modes of mobility involving reverse transcription of their RNA genomes in cytoplasmic virus-like particles (VLPs) and integration of the cDNA copies into the host genome. The limited coding capacity of retrotransposons necessitates an extensive reliance on host co-factors; however, it has been challenging to identify co-factors that are required for endogenous retrotransposon mobility because retrotransposition is such a rare event. Results To circumvent the low frequency of Ty1 LTR-retrotransposon mobility in Saccharomyces cerevisiae, we used iterative synthetic genetic array (SGA) analysis to isolate host mutations that reduce retrotransposition. Query strains that harbor a chromosomal Ty1his3AI reporter element and either the rtt101Δ or med1Δ mutation, both of which confer a hypertransposition phenotype, were mated to 4,847 haploid ORF deletion strains. Retrotransposition was measured in the double mutant progeny, and a set of 275 ORF deletions that suppress the hypertransposition phenotypes of both rtt101Δ and med1Δ were identified. The corresponding set of 275 retrotransposition host factors (RHFs) includes 45 previously identified Ty1 or Ty3 co-factors. More than half of the RHF genes have statistically robust human homologs (E < 1 x 10-10). The level of unintegrated Ty1 cDNA in 181 rhfΔ single mutants was altered <2-fold, suggesting that the corresponding co-factors stimulate retrotransposition at a step after cDNA synthesis. However, deletion of 43 RHF genes, including specific ribosomal protein and ribosome biogenesis genes and RNA degradation, modification and transport genes resulted in low Ty1 cDNA levels. The level of Ty1 Gag but not RNA was reduced in ribosome biogenesis mutants bud21Δ, hcr1Δ, loc1Δ, and puf6Δ. Conclusion Ty1 retrotransposition is dependent on multiple co-factors acting at different steps in the replication cycle. Human orthologs of these RHFs are

  15. Chemical inhibition of RNA viruses reveals REDD1 as a host defense factor.

    PubMed

    Mata, Miguel A; Satterly, Neal; Versteeg, Gijs A; Frantz, Doug; Wei, Shuguang; Williams, Noelle; Schmolke, Mirco; Peña-Llopis, Samuel; Brugarolas, James; Forst, Christian V; White, Michael A; García-Sastre, Adolfo; Roth, Michael G; Fontoura, Beatriz M A

    2011-10-01

    A chemical genetics approach was taken to identify inhibitors of NS1, a major influenza A virus virulence factor that inhibits host gene expression. A high-throughput screen of 200,000 synthetic compounds identified small molecules that reversed NS1-mediated inhibition of host gene expression. A counterscreen for suppression of influenza virus cytotoxicity identified naphthalimides that inhibited replication of influenza virus and vesicular stomatitis virus (VSV). The mechanism of action occurs through activation of REDD1 expression and concomitant inhibition of mammalian target of rapamycin complex 1 (mTORC1) via TSC1-TSC2 complex. The antiviral activity of naphthalimides was abolished in REDD1(-/-) cells. Inhibition of REDD1 expression by viruses resulted in activation of the mTORC1 pathway. REDD1(-/-) cells prematurely upregulated viral proteins via mTORC1 activation and were permissive to virus replication. In contrast, cells conditionally expressing high concentrations of REDD1 downregulated the amount of viral protein. Thus, REDD1 is a new host defense factor, and chemical activation of REDD1 expression represents a potent antiviral intervention strategy. PMID:21909097

  16. Avian necrotic enteritis: experimental models, host immunity, pathogenesis, risk factors, and vaccine development.

    PubMed

    Lee, K W; Lillehoj, H S; Jeong, W; Jeoung, H Y; An, D J

    2011-07-01

    The increasing trends of legislative restrictions and voluntary removal of antibiotic growth promoters worldwide has already affected, and will continue to affect, poultry production and animal health. Necrotic enteritis (NE) is being considered among the most important infectious diseases in the current poultry production system globally, with an estimated annual economic loss of more than $2 billion, largely attributable to medical treatments and impaired growth performance. Thus, there is an urgent need to develop rational, alternative, and integrated management strategies not only to control NE, but also to prevent it. In both humans and many warm-blooded animals and birds, NE is caused by Clostridium perfringens, a gram-positive, anaerobic, spore-forming bacterium. To accomplish these goals, better understanding of host- and environmentally related factors on the development of NE and potential vaccination strategies against C. perfringens infection will be necessary. Furthermore, a reliable and reproducible NE disease model is needed for characterization of C. perfringens pathogenesis and host protective immunity. This review summarizes recent developments in NE disease models, pathogenesis, host immunity, risk factors, and vaccine development for C. perfringens-associated NE in poultry. PMID:21673152

  17. The Host Plant Metabolite Glucose Is the Precursor of Diffusible Signal Factor (DSF) Family Signals in Xanthomonas campestris

    PubMed Central

    Liu, Xiaoling; Wu, Ji'en; Lee, Jasmine; Chen, Shaohua; Cheng, Yingying; Zhang, Chunyan

    2015-01-01

    Plant pathogen Xanthomonas campestris pv. campestris produces cis-11-methyl-2-dodecenoic acid (diffusible signal factor [DSF]) as a cell-cell communication signal to regulate biofilm dispersal and virulence factor production. Previous studies have demonstrated that DSF biosynthesis is dependent on the presence of RpfF, an enoyl-coenzyme A (CoA) hydratase, but the DSF synthetic mechanism and the influence of the host plant on DSF biosynthesis are still not clear. We show here that exogenous addition of host plant juice or ethanol extract to the growth medium of X. campestris pv. campestris could significantly boost DSF family signal production. It was subsequently revealed that X. campestris pv. campestris produces not only DSF but also BDSF (cis-2-dodecenoic acid) and another novel DSF family signal, which was designated DSF-II. BDSF was originally identified in Burkholderia cenocepacia to be involved in regulation of motility, biofilm formation, and virulence in B. cenocepacia. Functional analysis suggested that DSF-II plays a role equal to that of DSF in regulation of biofilm dispersion and virulence factor production in X. campestris pv. campestris. Furthermore, chromatographic separation led to identification of glucose as a specific molecule stimulating DSF family signal biosynthesis in X. campestris pv. campestris. 13C-labeling experiments demonstrated that glucose acts as a substrate to provide a carbon element for DSF biosynthesis. The results of this study indicate that X. campestris pv. campestris could utilize a common metabolite of the host plant to enhance DSF family signal synthesis and therefore promote virulence. PMID:25681189

  18. The host plant metabolite glucose is the precursor of diffusible signal factor (DSF) family signals in Xanthomonas campestris.

    PubMed

    Deng, Yinyue; Liu, Xiaoling; Wu, Ji'en; Lee, Jasmine; Chen, Shaohua; Cheng, Yingying; Zhang, Chunyan; Zhang, Lian-Hui

    2015-04-01

    Plant pathogen Xanthomonas campestris pv. campestris produces cis-11-methyl-2-dodecenoic acid (diffusible signal factor [DSF]) as a cell-cell communication signal to regulate biofilm dispersal and virulence factor production. Previous studies have demonstrated that DSF biosynthesis is dependent on the presence of RpfF, an enoyl-coenzyme A (CoA) hydratase, but the DSF synthetic mechanism and the influence of the host plant on DSF biosynthesis are still not clear. We show here that exogenous addition of host plant juice or ethanol extract to the growth medium of X. campestris pv. campestris could significantly boost DSF family signal production. It was subsequently revealed that X. campestris pv. campestris produces not only DSF but also BDSF (cis-2-dodecenoic acid) and another novel DSF family signal, which was designated DSF-II. BDSF was originally identified in Burkholderia cenocepacia to be involved in regulation of motility, biofilm formation, and virulence in B. cenocepacia. Functional analysis suggested that DSF-II plays a role equal to that of DSF in regulation of biofilm dispersion and virulence factor production in X. campestris pv. campestris. Furthermore, chromatographic separation led to identification of glucose as a specific molecule stimulating DSF family signal biosynthesis in X. campestris pv. campestris. (13)C-labeling experiments demonstrated that glucose acts as a substrate to provide a carbon element for DSF biosynthesis. The results of this study indicate that X. campestris pv. campestris could utilize a common metabolite of the host plant to enhance DSF family signal synthesis and therefore promote virulence. PMID:25681189

  19. Dissecting host factors that regulate the early stages of tuberculosis infection.

    PubMed

    Agrawal, Neha; Bhattacharyya, Chandrika; Mukherjee, Ankur; Ullah, Ubaid; Pandit, Bhaswati; Rao, Kanury V S; Majumder, Partha P

    2016-09-01

    Incomplete understanding of mechanisms involved in the host-pathogen interactions constrains our efforts to eliminate tuberculosis. In many individuals, resulting from immune response to mycobacterial infection organised structures called granulomas are formed. To identify host responses that may control at least the early stages of infection, we employed an in vitro granuloma model. Here, human PBMCs were infected with live Mycobacterium tuberculosis in culture, and the appearance of granuloma-like structures was monitored over the next several days. Production of cytokines and chemokines in culture supernatants was monitored at various times, and the resulting temporal profiles were examined for possible correlations with either granuloma formation, or bacterial growth. While a positive association of TNF-α and IFN-γ secretion levels with extent of granuloma formation could clearly be identified, we were, however, unable to detect any statistically significant relationship between any cytokine/chemokine and bacterial growth. Examination of specific host cellular biochemical pathways revealed that either modulation of neutral lipid homeostasis through inhibition of the Gi-protein coupled receptor GPR109A, or regulation of host metabolic pathways through addition of vitamin D, provided a more effective means of controlling infection. A subsequent genotypic analysis for a select subset of genes belonging to pathways known to be significant for TB pathology revealed associations of polymorphisms with cytokine secretions and bacterial growth independently. Collectively therefore, the present study supports that key metabolic pathways of the host cell, rather than levels of relevant cytokines/chemokines might be more critical for regulating the intracellular mycobacterial load, in the context of granuloma formation. PMID:27553417

  20. Extracellular Vesicles from Trypanosoma brucei Mediate Virulence Factor Transfer and Cause Host Anemia.

    PubMed

    Szempruch, Anthony J; Sykes, Steven E; Kieft, Rudo; Dennison, Lauren; Becker, Allison C; Gartrell, Anzio; Martin, William J; Nakayasu, Ernesto S; Almeida, Igor C; Hajduk, Stephen L; Harrington, John M

    2016-01-14

    Intercellular communication between parasites and with host cells provides mechanisms for parasite development, immune evasion, and disease pathology. Bloodstream African trypanosomes produce membranous nanotubes that originate from the flagellar membrane and disassociate into free extracellular vesicles (EVs). Trypanosome EVs contain several flagellar proteins that contribute to virulence, and Trypanosoma brucei rhodesiense EVs contain the serum resistance-associated protein (SRA) necessary for human infectivity. T. b. rhodesiense EVs transfer SRA to non-human infectious trypanosomes, allowing evasion of human innate immunity. Trypanosome EVs can also fuse with mammalian erythrocytes, resulting in rapid erythrocyte clearance and anemia. These data indicate that trypanosome EVs are organelles mediating non-hereditary virulence factor transfer and causing host erythrocyte remodeling, inducing anemia. PMID:26771494

  1. Implications for risk assessment of host factors causing large pharmacokinetic variations

    SciTech Connect

    Vesell, E.S.

    1985-12-01

    Normal human subjects vary widely in their capacity to eliminate many drugs and environmental chemicals. These variations range in magnitude from fourfold to fortyfold depending on the drug and the population studied. Pharmacogenetics deals with only one of many host factors responsible for these large pharmacokinetic differences. Age, sex, diet and exposure to other drugs and chemicals, including oral contraceptives, ethanol and cigarette smoking, can alter the genetically determined rate at which a particular subject eliminates drugs and environmental chemicals. These elimination rates, therefore, are dynamic and change even in the same subject with time and condition. Regulatory legislation has only recently begun to recognize this very broad spectrum of human susceptibility and the existence of multiple special subgroups of particularly sensitive subjects. In setting standards for environmental chemicals, EPA and NIOSH have attempted to protect the most sensitive humans and should be encouraged to continue this policy. For some drugs and environmental chemicals, the commonly used safety factor of 100 may be too low; for these chemicals large, interindividual pharmacokinetic variations produced by pharmacogenetic and other host factors may make a safety factor of 400 or 500 more adequate.

  2. Networks of Host Factors that Interact with NS1 Protein of Influenza A Virus

    PubMed Central

    Thulasi Raman, Sathya N.; Zhou, Yan

    2016-01-01

    Pigs are an important host of influenza A viruses due to their ability to generate reassortant viruses with pandemic potential. NS1 protein of influenza A viruses is a key virulence factor and a major antagonist of innate immune responses. It is also involved in enhancing viral mRNA translation and regulation of virus replication. Being a protein with pleiotropic functions, NS1 has a variety of cellular interaction partners. Hence, studies on swine influenza viruses (SIV) and identification of swine influenza NS1-interacting host proteins is of great interest. Here, we constructed a recombinant SIV carrying a Strep-tag in the NS1 protein and infected primary swine respiratory epithelial cells (SRECs) with this virus. The Strep-tag sequence in the NS1 protein enabled us to purify intact, the NS1 protein and its interacting protein complex specifically. We identified cellular proteins present in the purified complex by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and generated a dataset of these proteins. 445 proteins were identified by LC-MS/MS and among them 192 proteins were selected by setting up a threshold based on MS parameters. The selected proteins were analyzed by bioinformatics and were categorized as belonging to different functional groups including translation, RNA processing, cytoskeleton, innate immunity, and apoptosis. Protein interaction networks were derived using these data and the NS1 interactions with some of the specific host factors were verified by immunoprecipitation. The novel proteins and the networks revealed in our study will be the potential candidates for targeted study of the molecular interaction of NS1 with host proteins, which will provide insights into the identification of new therapeutic targets to control influenza infection and disease pathogenesis. PMID:27199973

  3. Genetic dissection of Flaviviridae host factors through genome-scale CRISPR screens.

    PubMed

    Marceau, Caleb D; Puschnik, Andreas S; Majzoub, Karim; Ooi, Yaw Shin; Brewer, Susan M; Fuchs, Gabriele; Swaminathan, Kavya; Mata, Miguel A; Elias, Joshua E; Sarnow, Peter; Carette, Jan E

    2016-07-01

    The Flaviviridae are a family of viruses that cause severe human diseases. For example, dengue virus (DENV) is a rapidly emerging pathogen causing an estimated 100 million symptomatic infections annually worldwide. No approved antivirals are available to date and clinical trials with a tetravalent dengue vaccine showed disappointingly low protection rates. Hepatitis C virus (HCV) also remains a major medical problem, with 160 million chronically infected patients worldwide and only expensive treatments available. Despite distinct differences in their pathogenesis and modes of transmission, the two viruses share common replication strategies. A detailed understanding of the host functions that determine viral infection is lacking. Here we use a pooled CRISPR genetic screening strategy to comprehensively dissect host factors required for these two highly important Flaviviridae members. For DENV, we identified endoplasmic-reticulum (ER)-associated multi-protein complexes involved in signal sequence recognition, N-linked glycosylation and ER-associated degradation. DENV replication was nearly completely abrogated in cells deficient in the oligosaccharyltransferase (OST) complex. Mechanistic studies pinpointed viral RNA replication and not entry or translation as the crucial step requiring the OST complex. Moreover, we show that viral non-structural proteins bind to the OST complex. The identified ER-associated protein complexes were also important for infection by other mosquito-borne flaviviruses including Zika virus, an emerging pathogen causing severe birth defects. By contrast, the most significant genes identified in the HCV screen were distinct and included viral receptors, RNA-binding proteins and enzymes involved in metabolism. We found an unexpected link between intracellular flavin adenine dinucleotide (FAD) levels and HCV replication. This study shows notable divergence in host-depenency factors between DENV and HCV, and illuminates new host targets for

  4. Factors affecting patterns of Amblyomma triste (Acari: Ixodidae) parasitism in a rodent host.

    PubMed

    Colombo, Valeria C; Nava, Santiago; Antoniazzi, Leandro R; Monje, Lucas D; Racca, Andrea L; Guglielmone, Alberto A; Beldomenico, Pablo M

    2015-07-30

    Here we offer a multivariable analysis that explores associations of different factors (i.e., environmental, host parameters, presence of other ectoparasites) with the interaction of Amblyomma triste immature stages and one of its main hosts in Argentina, the rodent Akodon azarae. Monthly and for two years, we captured and sampled rodents at 16 points located at 4 different sites in the Parana River Delta region. The analyses were conducted with Generalized Linear Mixed Models with a negative binomial response (counts of larvae or nymphs). The independent variables assessed were: (a) environmental: trapping year, season, presence of cattle; type of vegetation (natural grassland or implanted forest); rodent abundance; (b) host parameters: body length; sex; body condition; blood cell counts; natural antibody titres; and (c) co-infestation with other ectoparasites: other stage of A. triste; Ixodes loricatus; lice; mites; and fleas. Two-way interaction terms deemed a priori as relevant were also included in the analysis. Larvae were affected by all environmental variables assessed and by the presence of other ectoparasites (lice, fleas and other tick species). Host factors significantly associated with larval count were sex and levels of natural antibodies. Nymphs were associated with season, presence of cattle, body condition, body length and with burdens of I. loricatus. In most cases, the direction and magnitude of the associations were context-dependent (many interaction terms were significant). The findings of greater significance and implications of our study are two. Firstly, as burdens of A. triste larvae and nymphs were greater where cattle were present, and larval tick burdens were higher in implanted forests, silvopastoral practices developing in the region may affect the population dynamics of A. triste, and consequently the eco-epidemiology of Rickettsia parkeri. Secondly, strong associations and numerous interactions with other ectoparasites suggest that

  5. Viral and host inflammation-related factors that can predict the prognosis of hepatocellular carcinoma.

    PubMed

    Chen, Liping; Zhang, Qi; Chang, Wenjun; Du, Yan; Zhang, Hongwei; Cao, Guangwen

    2012-09-01

    Hepatocellular carcinoma (HCC), a malignancy caused mainly by chronic infection with hepatitis B virus (HBV) and/or hepatitis C virus (HCV), is a highly fatal disease. Apart from clinical parameters like venous invasion and multinodularity, viral and host inflammation-related factors are important predictors of HCC prognosis after surgical treatment. The factors of prognostic value can be detected in the specimens of HCC patients. In preoperative peripheral blood, high HBV DNA and the genotypes and mutations of HBV or HCV, high neutrophil-to-lymphocyte ratio and high concentrations of macrophage migration inhibitory factor and osteopontin predict poor prognosis. In tumours, high ratios of neutrophil-to-CD8(+) T cell and Treg-to-CD8(+) T cell, high expression of pro-angiogenic factors such as hypoxia-inducible factor-1α and cell growth/survival factors such as CD24 and activation of inflammatory signalling pathways such as Wnt/β-catenin, nuclear factor-kappa B and signal transducer and activator of transcription 3 predict early recurrence. In peritumoural hepatic tissues, high HBV DNA, HBV mutations, high densities of macrophages, activated stellates and mast cells, high expression of macrophage colony-stimulating factor/its receptor and placental growth factor, Th1/Th2-like cytokine shift, inflammation-related signature and activation of carcinogenesis-related pathways predict late recurrence. Further studies should be focused on the development of a robust strategy by integrating the viral factors, inflammatory factors and clinical factors of complementary prognostic value to ensure high validity of the assessment for postoperative HCC prognosis. PMID:22325840

  6. Butterfly Larval Host Plant use in a Tropical Urban Context: Life History Associations, Herbivory, and Landscape Factors

    PubMed Central

    Tiple, Ashish D.; Khurad, Arun M.; Dennis, Roger L. H.

    2011-01-01

    This study examines butterfly larval host plants, herbivory and related life history attributes within Nagpur City, India. The larval host plants of 120 butterfly species are identified and their host specificity, life form, biotope, abundance and perennation recorded; of the 126 larval host plants, most are trees (49), with fewer herbs (43), shrubs (22), climbers (7) and stem parasites (2). They include 89 wild, 23 cultivated, 11 wild/cultivated and 3 exotic plant species; 78 are perennials, 43 annuals and 5 biannuals. Plants belonging to Poaceae and Fabaceae are most widely used by butterfly larvae. In addition to distinctions in host plant family affiliation, a number of significant differences between butterfly families have been identified in host use patterns: for life forms, biotopes, landforms, perennation, host specificity, egg batch size and ant associations. These differences arising from the development of a butterfly resource database have important implications for conserving butterfly species within the city area. Differences in overall butterfly population sizes within the city relate mainly to the number of host plants used, but other influences, including egg batch size and host specificity are identified. Much of the variation in population size is unaccounted for and points to the need to investigate larval host plant life history and strategies as population size is not simply dependent on host plant abundance. PMID:21864159

  7. Butterfly larval host plant use in a tropical urban context: life history associations, herbivory, and landscape factors.

    PubMed

    Tiple, Ashish D; Khurad, Arun M; Dennis, Roger L H

    2011-01-01

    This study examines butterfly larval host plants, herbivory and related life history attributes within Nagpur City, India. The larval host plants of 120 butterfly species are identified and their host specificity, life form, biotope, abundance and perennation recorded; of the 126 larval host plants, most are trees (49), with fewer herbs (43), shrubs (22), climbers (7) and stem parasites (2). They include 89 wild, 23 cultivated, 11 wild/cultivated and 3 exotic plant species; 78 are perennials, 43 annuals and 5 biannuals. Plants belonging to Poaceae and Fabaceae are most widely used by butterfly larvae. In addition to distinctions in host plant family affiliation, a number of significant differences between butterfly families have been identified in host use patterns: for life forms, biotopes, landforms, perennation, host specificity, egg batch size and ant associations. These differences arising from the development of a butterfly resource database have important implications for conserving butterfly species within the city area. Differences in overall butterfly population sizes within the city relate mainly to the number of host plants used, but other influences, including egg batch size and host specificity are identified. Much of the variation in population size is unaccounted for and points to the need to investigate larval host plant life history and strategies as population size is not simply dependent on host plant abundance. PMID:21864159

  8. Host and Microbial Factors in Regulation of T Cells in the Intestine

    PubMed Central

    Kim, Chang H.

    2013-01-01

    The intestine is divided into specialized tissue areas that provide distinct microenvironments for T cells. Regulation of T-cell responses in the gut has been a major focus of recent research activities in the field. T cells in the intestine are regulated by the interplay between host and microbial factors. In the small intestine, retinoic acid (RA) is a major tissue factor that plays important roles in regulation of immune responses. In the large intestine, the influence of RA diminishes, but that of commensal bacterial products increases. RA, gut microbiota, and inflammatory mediators co-regulate differentiation, distribution, and/or effector functions of T cells. Coordinated regulation of immune responses by these factors promotes well-balanced immunity and immune tolerance. Dysregulation of this process can increase infection and inflammatory diseases. PMID:23772228

  9. Environment-related and host-related factors affecting the occurrence of lice on rodents in Central Europe.

    PubMed

    Stanko, Michal; Fričová, Jana; Miklisová, Dana; Khokhlova, Irina S; Krasnov, Boris R

    2015-06-01

    We studied the effects of environment- (habitat, season) and host-related (sex, body mass) factors on the occurrence of four species of lice (Insecta:Phthiraptera:Anoplura) on six rodent species (Rodentia:Muridae). We asked how these factors influence the occurrence of lice on an individual host and whether different rodent-louse associations demonstrate consistent trends in these effects. We found significant effects of at least one environment-related and at least one host-related factor on the louse occurrence in five of six host-louse associations. The effect of habitat was significant in two associations with the occurrence of lice being more frequent in lowland than in mountain habitats. The effect of season was significant in five associations with a higher occurrence of infestation during the warm season in four associations and the cold season in one association. Host sex affected significantly the infestation by lice in three associations with a higher frequency of infestation in males. Host body mass affected the occurrence of lice in all five associations, being negative in wood mice and positive in voles. In conclusion, lice were influenced not only by the host- but also by environment-related factors. The effects of the latter could be mediated via life history parameters of a host. PMID:25651932

  10. Human Host Defense Peptide LL-37 Stimulates Virulence Factor Production and Adaptive Resistance in Pseudomonas aeruginosa

    PubMed Central

    Strempel, Nikola; Neidig, Anke; Nusser, Michael; Geffers, Robert; Vieillard, Julien; Lesouhaitier, Olivier; Brenner-Weiss, Gerald; Overhage, Joerg

    2013-01-01

    A multitude of different virulence factors as well as the ability to rapidly adapt to adverse environmental conditions are important features for the high pathogenicity of Pseudomonas aeruginosa. Both virulence and adaptive resistance are tightly controlled by a complex regulatory network and respond to external stimuli, such as host signals or antibiotic stress, in a highly specific manner. Here, we demonstrate that physiological concentrations of the human host defense peptide LL-37 promote virulence factor production as well as an adaptive resistance against fluoroquinolone and aminoglycoside antibiotics in P. aeruginosa PAO1. Microarray analyses of P. aeruginosa cells exposed to LL-37 revealed an upregulation of gene clusters involved in the production of quorum sensing molecules and secreted virulence factors (PQS, phenazine, hydrogen cyanide (HCN), elastase and rhamnolipids) and in lipopolysaccharide (LPS) modification as well as an induction of genes encoding multidrug efflux pumps MexCD-OprJ and MexGHI-OpmD. Accordingly, we detected significantly elevated levels of toxic metabolites and proteases in bacterial supernatants after LL-37 treatment. Pre-incubation of bacteria with LL-37 for 2 h led to a decreased susceptibility towards gentamicin and ciprofloxacin. Quantitative Realtime PCR results using a PAO1-pqsE mutant strain present evidence that the quinolone response protein and virulence regulator PqsE may be implicated in the regulation of the observed phenotype in response to LL-37. Further experiments with synthetic cationic antimicrobial peptides IDR-1018, 1037 and HHC-36 showed no induction of pqsE expression, suggesting a new role of PqsE as highly specific host stress sensor. PMID:24349231

  11. Human host defense peptide LL-37 stimulates virulence factor production and adaptive resistance in Pseudomonas aeruginosa.

    PubMed

    Strempel, Nikola; Neidig, Anke; Nusser, Michael; Geffers, Robert; Vieillard, Julien; Lesouhaitier, Olivier; Brenner-Weiss, Gerald; Overhage, Joerg

    2013-01-01

    A multitude of different virulence factors as well as the ability to rapidly adapt to adverse environmental conditions are important features for the high pathogenicity of Pseudomonas aeruginosa. Both virulence and adaptive resistance are tightly controlled by a complex regulatory network and respond to external stimuli, such as host signals or antibiotic stress, in a highly specific manner. Here, we demonstrate that physiological concentrations of the human host defense peptide LL-37 promote virulence factor production as well as an adaptive resistance against fluoroquinolone and aminoglycoside antibiotics in P. aeruginosa PAO1. Microarray analyses of P. aeruginosa cells exposed to LL-37 revealed an upregulation of gene clusters involved in the production of quorum sensing molecules and secreted virulence factors (PQS, phenazine, hydrogen cyanide (HCN), elastase and rhamnolipids) and in lipopolysaccharide (LPS) modification as well as an induction of genes encoding multidrug efflux pumps MexCD-OprJ and MexGHI-OpmD. Accordingly, we detected significantly elevated levels of toxic metabolites and proteases in bacterial supernatants after LL-37 treatment. Pre-incubation of bacteria with LL-37 for 2 h led to a decreased susceptibility towards gentamicin and ciprofloxacin. Quantitative Realtime PCR results using a PAO1-pqsE mutant strain present evidence that the quinolone response protein and virulence regulator PqsE may be implicated in the regulation of the observed phenotype in response to LL-37. Further experiments with synthetic cationic antimicrobial peptides IDR-1018, 1037 and HHC-36 showed no induction of pqsE expression, suggesting a new role of PqsE as highly specific host stress sensor. PMID:24349231

  12. Uptake of Host Cell Transforming Growth Factor-β by Trypanosoma cruzi Amastigotes in Cardiomyocytes

    PubMed Central

    Waghabi, Mariana C.; Keramidas, Michelle; Bailly, Sabine; Degrave, Wim; Mendonça-Lima, Leila; Soeiro, Maria de Nazaré C.; Meirelles, Maria de Nazareth L.; Paciornik, Sidnei; Araújo-Jorge, Tania C.; Feige, Jean-Jacques

    2005-01-01

    The cytokine transforming growth factor-β (TGF-β) plays various functions in the control of Trypanosoma cruzi infectivity and in the progression of Chagas’ disease. When we immunostained T. cruzi-infected cardiomyocytes (after either in vivo or in vitro infections) for TGF-β, we observed stronger immunoreactivity in parasites than in host cells. TGF-β immunoreactivity evolved during parasite cycle progression, with intense staining in amastigotes versus very faint staining in trypomastigotes. TGF-β was present on the surface of amastigotes, in the flagellar pocket, and in intraparasitic vesicles as revealed by electron microscopy. However, no ortholog TGF-β gene could be identified in the genome of T. cruzi by in silico analysis or by extensive polymerase chain reaction and reverse transcriptase-polymerase chain reaction studies. Immunoreactive TGF-β was most probably taken up by the parasite from the host cell cytoplasm because such an internalization process of biotinylated TGF-β could be observed in axenic amastigotes in vitro. These observations represent the first example of a novel mechanism by which a primitive unicellular protozoan can use host cell TGF-β to control its own intracellular life cycle. PMID:16192635

  13. A Multi-Host Approach for the Systematic Analysis of Virulence Factors in Cryptococcus neoformans

    PubMed Central

    Desalermos, Athanasios; Tan, Xiaojiang; Rajamuthiah, Rajmohan; Arvanitis, Marios; Wang, Yan; Li, Dedong; Kourkoumpetis, Themistoklis K.; Fuchs, Beth Burgwyn; Mylonakis, Eleftherios

    2015-01-01

    A multi-host approach was followed to screen a library of 1201 signature-tagged deletion strains of Cryptococcus neoformans mutants to identify previously unknown virulence factors. The primary screen was performed using a Caenorhabditis elegans–C. neoformans infection assay. The hits among these strains were reconfirmed as less virulent than the wild type in the insect Galleria mellonella–C. neoformans infection assay. After this 2-stage screen, and to prioritize hits, we performed serial evaluations of the selected strains, using the C. elegans model. All hit strains identified through these studies were validated in a murine model of systemic cryptococcosis. Twelve strains were identified through a stepwise screening assay. Among them, 4 (CSN1201, SRE1, RDI1, and YLR243W) were previously discovered, providing proof of principle for this approach, while the role of the remaining 8 genes (CKS101, CNC5600, YOL003C, CND1850, MLH3, HAP502, MSL5, and CNA2580) were not previously described in cryptococcal virulence. The multi-host approach is an efficient method of studying the pathogenesis of C. neoformans. We used diverse model hosts, C. elegans, G. mellonella, and mice, with physiological differences and identified 12 genes associated with mammalian infection. Our approach may be suitable for large pathogenesis screens. PMID:25114160

  14. Infection of human urethral epithelium with Neisseria gonorrhoeae elicits an upregulation of host anti-apoptotic factors and protects cells from staurosporine-induced apoptosis.

    PubMed

    Binnicker, Matthew J; Williams, Richard D; Apicella, Michael A

    2003-08-01

    In order to better understand the host response to an infection with Neisseria gonorrhoeae, microarray technology was used to analyse the gene expression profile between uninfected and infected human urethral epithelium. The anti-apoptotic genes bfl-1, cox-2 and c-IAP-2 were identified to be upregulated approximately eight-, four- or twofold, respectively, following infection. Subsequent assays including RT-PCR, real time RT-PCR and RNase protection confirmed the increased expression of these apoptotic regulators, and identified that a fourth anti-apoptotic factor, mcl-1, is also upregulated. RT-PCR and RNase protection also showed that key pro-apoptotic factors including bax, bad and bak do not change in expression. Furthermore, our studies demonstrated that infection with the gonococcus partially protects urethral epithelium from apoptosis induced by the protein kinase inhibitor, staurosporine (STS). This work shows that following infection with Neisseria gonorrhoeae, several host anti-apoptotic factors are upregulated. In addition, a gonococcal infection protects host cells from subsequent STS-induced death. The regulation of host cell death by the gonococcus may represent a mechanism employed by this pathogen to survive and proliferate in host epithelium. PMID:12864814

  15. 34 CFR 477.22 - What additional factors does the Secretary consider?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION STATE PROGRAM ANALYSIS ASSISTANCE AND POLICY STUDIES PROGRAM How Does the Secretary Make an Award? § 477.22 What additional factors does the... 34 Education 3 2011-07-01 2011-07-01 false What additional factors does the Secretary...

  16. Role of the host restriction factor APOBEC3 on papillomavirus evolution

    PubMed Central

    Warren, Cody J.; Van Doorslaer, Koenraad; Pandey, Ahwan; Espinosa, Joaquin M.; Pyeon, Dohun

    2016-01-01

    More than 270 different types of papillomaviruses have been discovered in a wide array of animal species. Despite the great diversity of papillomaviruses, little is known about the evolutionary processes that drive host tropism and the emergence of oncogenic genotypes. Although host defense mechanisms have evolved to interfere with various aspects of a virus life cycle, viruses have also coevolved copious strategies to avoid host antiviral restriction. Our and other studies have shown that the cytidine deaminase APOBEC3 family members edit HPV genomes and restrict virus infectivity. Thus, we hypothesized that host restriction by APOBEC3 served as selective pressure during papillomavirus evolution. To test this hypothesis, we analyzed the relative abundance of all dinucleotide sequences in full-length genomes of 274 papillomavirus types documented in the Papillomavirus Episteme database (PaVE). Here, we report that TC dinucleotides, the preferred target sequence of several human APOBEC3 proteins (hA3A, hA3B, hA3F, and hA3H), are highly depleted in papillomavirus genomes. Given that HPV infection is highly tissue-specific, the expression levels of APOBEC3 family members were analyzed. The basal expression levels of all APOBEC3 isoforms, excluding hA3B, are significantly higher in mucosal skin compared with cutaneous skin. Interestingly, we reveal that Alphapapillomaviruses (alpha-PVs), a majority of which infects anogenital mucosa, display the most dramatic reduction in TC dinucleotide content. Computer modeling and reconstruction of ancestral alpha-PV genomes suggest that TC depletion occurred after the alpha-PVs diverged from their most recent common ancestor. In addition, we found that TC depletion in alpha-PVs is greatly affected by protein coding potential. Taken together, our results suggest that PVs replicating in tissues with high APOBEC3 levels may have evolved to evade restriction by selecting for variants that contain reduced APOBEC3 target sites in their

  17. Endogenous growth factor stimulation of hemocyte proliferation induces resistance to Schistosoma mansoni challenge in the snail host.

    PubMed

    Pila, Emmanuel A; Gordy, Michelle A; Phillips, Valerie K; Kabore, Alethe L; Rudko, Sydney P; Hanington, Patrick C

    2016-05-10

    Digenean trematodes are a large, complex group of parasitic flatworms that infect an incredible diversity of organisms, including humans. Larval development of most digeneans takes place within a snail (Gastropoda). Compatibility between snails and digeneans is often very specific, such that suitable snail hosts define the geographical ranges of diseases caused by these worms. The immune cells (hemocytes) of a snail are sentinels that act as a crucial barrier to infection by larval digeneans. Hemocytes coordinate a robust and specific immunological response, participating directly in parasite killing by encapsulating and clearing the infection. Hemocyte proliferation and differentiation are influenced by unknown digenean-specific exogenous factors. However, we know nothing about the endogenous control of hemocyte development in any gastropod model. Here, we identify and functionally characterize a progranulin [Biomphalaria glabrata granulin (BgGRN)] from the snail B. glabrata, a natural host for the human blood fluke Schistosoma mansoni Granulins are growth factors that drive proliferation of immune cells in organisms, spanning the animal kingdom. We demonstrate that BgGRN induces proliferation of B. glabrata hemocytes, and specifically drives the production of an adherent hemocyte subset that participates centrally in the anti-digenean defense response. Additionally, we demonstrate that susceptible B. glabrata snails can be made resistant to infection with S. mansoni by first inducing hemocyte proliferation with BgGRN. This marks the functional characterization of an endogenous growth factor of a gastropod mollusc, and provides direct evidence of gain of resistance in a snail-digenean infection model using a defined factor to induce snail resistance to infection. PMID:27114544

  18. Multi-Faceted Proteomic Characterization of Host Protein Complement of Rift Valley Fever Virus Virions and Identification of Specific Heat Shock Proteins, Including HSP90, as Important Viral Host Factors

    PubMed Central

    Nuss, Jonathan E.; Kehn-Hall, Kylene; Benedict, Ashwini; Costantino, Julie; Ward, Michael; Peyser, Brian D.; Retterer, Cary J.; Tressler, Lyal E.; Wanner, Laura M.; McGovern, Hugh F.; Zaidi, Anum; Anthony, Scott M.; Kota, Krishna P.; Bavari, Sina; Hakami, Ramin M.

    2014-01-01

    Rift Valley fever is a potentially fatal disease of humans and domestic animals caused by Rift Valley fever virus (RVFV). Infection with RVFV in ruminants can cause near 100% abortion rates and recent outbreaks in naïve human populations have suggested case fatality rates of greater than thirty percent. To elucidate the roles that host proteins play during RVFV infection, proteomic analysis of RVFV virions was conducted using complementary analytical approaches, followed by functional validation studies of select identified host factors. Coupling the more traditional Gel LC/MS/MS approach (SDS PAGE followed by liquid chromatography tandem mass spectrometry) with an alternative technique that preserves protein complexes allowed the protein complement of these viral particles to be thoroughly examined. In addition to viral proteins present within the virions and virion-associated host proteins, multiple macromolecular complexes were identified. Bioinformatic analysis showed that host chaperones were among over-represented protein families associated with virions, and functional experiments using siRNA gene silencing and small molecule inhibitors identified several of these heat shock proteins, including heat shock protein 90 (HSP90), as important viral host factors. Further analysis indicated that HSP inhibition effects occur during the replication/transcription phase of the virus life cycle, leading to significant lowering of viral titers without compromising the functional capacity of released virions. Overall, these studies provide much needed further insight into interactions between RVFV and host cells, increasing our understanding of the infection process and suggesting novel strategies for anti-viral development. In particular, considering that several HSP90 inhibitors have been advancing through clinical trials for cancer treatment, these results also highlight the exciting potential of repurposing HSP90 inhibitors to treat RVF. PMID:24809507

  19. A High Throughput Assay for Screening Host Restriction Factors and Antivirals Targeting Influenza A Virus

    PubMed Central

    Wang, Lingyan; Li, Wenjun; Li, Shitao

    2016-01-01

    Influenza A virus (IAV) is a human respiratory pathogen that causes seasonal epidemics and occasional global pandemics with devastating levels of morbidity and mortality. Currently approved treatments against influenza are losing effectiveness, as new viral strains are often refractory to conventional treatments. Thus, there is an urgent need to find new therapeutic targets with which to develop novel antiviral drugs. The common strategy to discover new drug targets and antivirals is high throughput screening. However, most current screenings for IAV rely on the engineered virus carrying a reporter, which prevents the application to newly emerging wild type flu viruses, such as 2009 pandemic H1N1 flu. Here we developed a simple and sensitive screening assay for wild type IAV by quantitatively analyzing viral protein levels using a Dot Blot Assay in combination with the LI-COR Imaging System (DBALIS). We first validated DBALIS in overexpression and RNAi assays, which are suitable methods for screening host factors regulating viral infection. More importantly, we also validated and initiated drug screening using DBALIS. A pilot compound screening identified a small molecule that inhibited IAV infection. Taken together, our method represents a reliable and convenient high throughput assay for screening novel host factors and antiviral compounds. PMID:27375580

  20. A High Throughput Assay for Screening Host Restriction Factors and Antivirals Targeting Influenza A Virus.

    PubMed

    Wang, Lingyan; Li, Wenjun; Li, Shitao

    2016-01-01

    Influenza A virus (IAV) is a human respiratory pathogen that causes seasonal epidemics and occasional global pandemics with devastating levels of morbidity and mortality. Currently approved treatments against influenza are losing effectiveness, as new viral strains are often refractory to conventional treatments. Thus, there is an urgent need to find new therapeutic targets with which to develop novel antiviral drugs. The common strategy to discover new drug targets and antivirals is high throughput screening. However, most current screenings for IAV rely on the engineered virus carrying a reporter, which prevents the application to newly emerging wild type flu viruses, such as 2009 pandemic H1N1 flu. Here we developed a simple and sensitive screening assay for wild type IAV by quantitatively analyzing viral protein levels using a Dot Blot Assay in combination with the LI-COR Imaging System (DBALIS). We first validated DBALIS in overexpression and RNAi assays, which are suitable methods for screening host factors regulating viral infection. More importantly, we also validated and initiated drug screening using DBALIS. A pilot compound screening identified a small molecule that inhibited IAV infection. Taken together, our method represents a reliable and convenient high throughput assay for screening novel host factors and antiviral compounds. PMID:27375580

  1. Viral and host factors that contribute to pathogenicity of enterovirus 71.

    PubMed

    Huang, Hsing-I; Weng, Kuo-Feng; Shih, Shin-Ru

    2012-04-01

    The single-stranded RNA virus enterovirus 71 (EV71), which belongs to the Picornaviridae family, has caused epidemics worldwide, particularly in the Asia-Pacific region. Most EV71 infections result in mild clinical symptoms, including herpangina and hand, foot and mouth disease. However, serious pathological complications have also been reported, especially for young children. The mechanisms of EV71 disease progression remain unclear. The pathogenesis of adverse clinical outcomes may relate to many factors, including cell tropism, cell death and host immune responses. This article reviews the recent advances in the identification of factors determining EV71 cell tropism, the associated mechanisms of viral infection-induced cell death and the interplay between EV71 and immunity. PMID:22439724

  2. Host factors are dominant in the development of post-liver transplant non-alcoholic steatohepatitis

    PubMed Central

    Boga, Salih; Munoz-Abraham, Armando Salim; Rodriguez-Davalos, Manuel I; Emre, Sukru H; Jain, Dhanpat; Schilsky, Michael L

    2016-01-01

    Non-alcoholic fatty liver disease (NAFLD) is a recognized problem in patients after orthotopic liver transplantation and may lead to recurrent graft injury. As the increased demand for liver allografts fail to match the available supply of donor organs, split liver transplantation (SLT) has emerged as an important technique to increase the supply of liver grafts. SLT allows two transplants to occur from one donor organ, and provides a unique model for observing the pathogenesis of NAFLD with respect to the role of recipient environmental and genetic factors. Here we report on two recipients of a SLT from the same deceased donor where only one developed non-alcoholic steatohepatitis (NASH), suggesting that host factors are critical for the development of NASH. PMID:27239259

  3. Influence of Host Factors on Immunoglobulin G Concentration in Oral Fluid Specimens

    PubMed Central

    Granade, Timothy C.; Phillips, Susan K.; Kitson-Piggott, Wendy; Gomez, Perry; Mahabir, Bisram; Oleander, Herbert; George, J. Richard; Baggs, James; Parekh, Bharat

    2002-01-01

    The influence of host factors (tobacco use, dentition, bleeding gums, oral rinsing, nasal medications, and time since the last meal) on immunoglobulin G (IgG) concentration in oral fluids (OF) was determined by univariate and multivariate analysis. Significant differences in IgG concentration were found to be associated with human immunodeficiency virus (HIV) status (HIV antibody positive, +16.60 μg/ml, P = 0.0001), sex (female, +1.23 μg/ml, P = 0.004), dentition (+2.83 μg/ml, edentulous versus dentulous, P = 0.0001), bleeding gums (+6.35 μg/ml, P = 0.0001), and time since the last meal (+3.55 μg/ml, >6 h, P = 0.0001). These factors could impact diagnostic methods that rely on the immunoglobulin concentration in OF specimens. PMID:11777855

  4. Host factors are dominant in the development of post-liver transplant non-alcoholic steatohepatitis.

    PubMed

    Boga, Salih; Munoz-Abraham, Armando Salim; Rodriguez-Davalos, Manuel I; Emre, Sukru H; Jain, Dhanpat; Schilsky, Michael L

    2016-05-28

    Non-alcoholic fatty liver disease (NAFLD) is a recognized problem in patients after orthotopic liver transplantation and may lead to recurrent graft injury. As the increased demand for liver allografts fail to match the available supply of donor organs, split liver transplantation (SLT) has emerged as an important technique to increase the supply of liver grafts. SLT allows two transplants to occur from one donor organ, and provides a unique model for observing the pathogenesis of NAFLD with respect to the role of recipient environmental and genetic factors. Here we report on two recipients of a SLT from the same deceased donor where only one developed non-alcoholic steatohepatitis (NASH), suggesting that host factors are critical for the development of NASH. PMID:27239259

  5. Expression profile of host restriction factors in HIV-1 elite controllers

    PubMed Central

    2013-01-01

    Background Several host-encoded antiviral factors suppress HIV-1 replication in a cell-autonomous fashion in vitro. The relevance of these defenses to the control of HIV-1 in vivo remains to be elucidated. We hypothesized that cellular restriction of HIV-1 replication plays a significant role in the observed suppression of HIV-1 in "elite controllers", individuals who maintain undetectable levels of viremia in the absence of antiretroviral therapy (ART). We comprehensively compared the expression levels of 34 host restriction factors and cellular activation levels in CD4+ T cells and sorted T cell subsets between elite controllers, HIV-1-infected (untreated) non-controllers, ART-suppressed, and uninfected individuals. Results Expression of schlafen 11, a codon usage-based inhibitor of HIV-1 protein synthesis, was significantly elevated in CD4+ T cells from elite controllers as compared to both non-controllers (p = 0.048) and ART-suppressed individuals (p = 0.024), with this effect most apparent in central memory CD4+ T cells. Schlafen 11 expression levels were comparable between controllers and uninfected individuals. Cumulative restriction factor expression was positively correlated with CD4+ T cell activation (r2 = 0.597, p < 0.0001), viral load (r2 = 0.34, p = 0.015), and expression of ISG15 (r2 = 0.73, p < 0.0001), a marker of interferon exposure. APOBEC3C, APOBEC3D, CTR9, TRIM26, and TRIM32 were elevated in elite controllers with respect to ART-suppressed individuals, while levels were comparable to uninfected individuals and non-controllers. Conclusions Host restriction factor expression typically scales with cellular activation levels. However, the elevated mRNA and protein expression of schlafen 11, despite low activation and viral load, violates the global pattern and may be a signature characteristic of HIV-1 elite control. PMID:24131498

  6. Museum specimens reveal loss of pollen host plants as key factor driving wild bee decline in The Netherlands.

    PubMed

    Scheper, Jeroen; Reemer, Menno; van Kats, Ruud; Ozinga, Wim A; van der Linden, Giel T J; Schaminée, Joop H J; Siepel, Henk; Kleijn, David

    2014-12-01

    Evidence for declining populations of both wild and managed bees has raised concern about a potential global pollination crisis. Strategies to mitigate bee loss generally aim to enhance floral resources. However, we do not really know whether loss of preferred floral resources is the key driver of bee decline because accurate assessment of host plant preferences is difficult, particularly for species that have become rare. Here we examine whether population trends of wild bees in The Netherlands can be explained by trends in host plants, and how this relates to other factors such as climate change. We determined host plant preference of bee species using pollen loads on specimens in entomological collections that were collected before the onset of their decline, and used atlas data to quantify population trends of bee species and their host plants. We show that decline of preferred host plant species was one of two main factors associated with bee decline. Bee body size, the other main factor, was negatively related to population trend, which, because larger bee species have larger pollen requirements than smaller species, may also point toward food limitation as a key factor driving wild bee loss. Diet breadth and other potential factors such as length of flight period or climate change sensitivity were not important in explaining twentieth century bee population trends. These results highlight the species-specific nature of wild bee decline and indicate that mitigation strategies will only be effective if they target the specific host plants of declining species. PMID:25422416

  7. Comprehensive Assessment of Host Responses to Ionizing Radiation by Nuclear Factor-κB Bioluminescence Imaging-Guided Transcriptomic Analysis

    PubMed Central

    Chang, Chung-Ta; Lin, Ho; Ho, Tin-Yun; Li, Chia-Cheng; Lo, Hsin-Yi; Wu, Shih-Lu; Huang, Yi-Fang

    2011-01-01

    The aim of this study was to analyze the host responses to ionizing radiation by nuclear factor-κB (NF-κB) bioluminescence imaging-guided transcriptomic tool. Transgenic mice carrying the NF-κB-driven luciferase gene were exposed to a single dose of 8.5 Gy total-body irradiation. In vivo imaging showed that a maximal NF-κB-dependent bioluminescent intensity was observed at 3 h after irradiation and ex vivo imaging showed that liver, intestine, and brain displayed strong NF-κB activations. Microarray analysis of these organs showed that irradiation altered gene expression signatures in an organ-specific manner and several pathways associated with metabolism and immune system were significantly altered. Additionally, the upregulation of fatty acid binding protein 4, serum amyloid A2, and serum amyloid A3 genes, which participate in both inflammation and lipid metabolism, suggested that irradiation might affect the cross pathways of metabolism and inflammation. Moreover, the alteration of chemokine (CC-motif) ligand 5, chemokine (CC-motif) ligand 20, and Jagged 1 genes, which are involved in the inflammation and enterocyte proliferation, suggested that these genes might be involved in the radiation enteropathy. In conclusion, this report describes the comprehensive evaluation of host responses to ionizing radiation. Our findings provide the fundamental information about the in vivo NF-κB activity and transcriptomic pattern after irradiation. Moreover, novel targets involved in radiation injury are also suggested. PMID:21887294

  8. Risk factors for syngeneic graft-versus-host disease after adult hematopoietic cell transplantation.

    PubMed

    Adams, Kristina M; Holmberg, Leona A; Leisenring, Wendy; Fefer, Alexander; Guthrie, Katherine A; Tylee, Tracy S; McDonald, George B; Bensinger, William I; Nelson, J Lee

    2004-09-15

    Syngeneic graft-versus-host disease (sGVHD) has been described after hematopoietic cell transplantation (HCT) but remains poorly defined. We retrospectively reviewed adult syngeneic HCTs at our center (1980-2002) for sGVHD to investigate incidence, morbidity, and risk factors with a primary focus on parity. Among 119 transplantations, there were 21 cases of biopsy-proven sGVHD. The cumulative incidence was 18%, with multiorgan involvement in 6 cases and 1 death. sGVHD was more frequent when the donor was parous (32%) than nulliparous (9%) or male (13%; P =.03) and when the recipient was parous (31%) than nulliparous (7%) or male (13%; P =.02). Other univariable risk factors included older age (P <.01), busulfan/melphalan/thiotepa conditioning (P <.01), interleukin-2 (P =.02), HLA-A26 (P =.03), and more recent transplantation year (P <.01). Overall, risk factors were similar to those described in GVHD. Although an independent effect of parity could not be completely separated from other factors, donor and recipient pregnancy history merits further investigation. PMID:15117763

  9. Encapsidation of Host-Derived Factors Correlates with Enhanced Infectivity of Sindbis Virus

    PubMed Central

    Sokoloski, Kevin J.; Snyder, Anthony J.; Liu, Natalia H.; Hayes, Chelsea A.

    2013-01-01

    The genus Alphavirus consists of a group of enveloped, single-stranded RNA viruses, many of which are transmitted by arthropods to a wide range of vertebrate host species. Here we report that Sindbis virus (SINV) produced from a representative mammalian cell line consists of at least two unique particle subpopulations, separable on the basis of virion density. In contrast, mosquito-derived SINV consists of a homogeneous population of particles. Our findings indicate that the denser particle subpopulation, SINVHeavy, is more infectious on a per-particle basis than SINVLight. SINV produced in mosquito cell lines (SINVC6/36) exhibited particle-to-PFU ratios similar to those observed for SINVHeavy. In mammalian cells, viral RNA was synthesized and accumulated more rapidly following infection with SINVHeavy or SINVC6/36 than following infection with SINVLight, due partly to enhanced translation of viral genomic RNA early in infection. Analysis of the individual particle subpopulations indicated that SINVHeavy and SINVC6/36 contain host-derived factors whose presence correlates with the enhanced translation, RNA synthesis, and infectivity observed for these particles. PMID:24006438

  10. GRA25 Is a Novel Virulence Factor of Toxoplasma gondii and Influences the Host Immune Response

    PubMed Central

    Shastri, Anjali J.; Marino, Nicole D.; Franco, Magdalena; Lodoen, Melissa B.

    2014-01-01

    The obligate intracellular parasite Toxoplasma gondii is able to infect a broad range of hosts and cell types due, in part, to the diverse arsenal of effectors it secretes into the host cell. Here, using genetic crosses between type II and type III Toxoplasma strains and quantitative trait locus (QTL) mapping of the changes they induce in macrophage gene expression, we identify a novel dense granule protein, GRA25. Encoded on chromosome IX, GRA25 is a phosphoprotein that is secreted outside the parasites and is found within the parasitophorous vacuole. In vitro experiments with a type II Δgra25 strain showed that macrophages infected with this strain secrete lower levels of CCL2 and CXCL1 than those infected with the wild-type or complemented control parasites. In vivo experiments showed that mice infected with a type II Δgra25 strain are able to survive an otherwise lethal dose of Toxoplasma tachyzoites and that complementation of the mutant with an ectopic copy of GRA25 largely rescues this phenotype. Interestingly, the type II and type III versions of GRA25 differ in endogenous expression levels; however, both are able to promote parasite expansion in vivo when expressed in a type II Δgra25 strain. These data establish GRA25 as a novel virulence factor and immune modulator. PMID:24711568

  11. Spatial, temporal and host factors structure the Ceratomyxa shasta (Myxozoa) population in the Klamath River basin.

    PubMed

    Atkinson, Stephen D; Bartholomew, Jerri L

    2010-10-01

    The myxozoan parasite Ceratomyxa shasta is a virulent pathogen of salmonid fish in the Klamath River, Oregon/California, USA. We previously defined four principal genotypes of the parasite (O, I, II, III) based on a trinucleotide repeat (ATC)(0-3) in Internal Transcribed Spacer region 1 sequences. Genotypes occur in sympatry and show marked host preference: I in Chinook salmon (Oncorhynchus tschawytscha) and II in non-native rainbow trout (O. mykiss). In the present study, we sequenced the parasite from river water samples collected in May, June and September at three localities below, above and between the Klamath's five dams. We also sampled adult and juvenile coho salmon (O. kisutch), steelhead trout (O. mykiss, anadromous form) and native redband rainbow trout (O. mykiss, freshwater form) and additional Chinook salmon and non-native rainbow trout. We found that the C. shasta population was highly structured spatially, temporally and with respect to fish host species. Genotype O was present in water throughout the basin but detected almost exclusively in steelhead and native rainbow trout. Genotype I was in water only below the dams and detected only in Chinook salmon. Genotype II was detected in coho salmon below the dams, and in non-native rainbow trout exposed both above and below the dams. The same genotypes were detected in adult and juvenile fish of the same species. These findings have major implications for the design of effective surveillance and control programs for this economically and ecologically important fish parasite. PMID:20601174

  12. MiR-22 promotes porcine reproductive and respiratory syndrome virus replication by targeting the host factor HO-1.

    PubMed

    Xiao, Shuqi; Du, Taofeng; Wang, Xue; Ni, Huaibao; Yan, Yunhuan; Li, Na; Zhang, Chong; Zhang, Angke; Gao, Jiming; Liu, Hongliang; Pu, Fengxing; Zhang, Gaiping; Zhou, En-Min

    2016-08-30

    Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most economically important viruses affecting the swine industry worldwide. MicroRNAs (miRNAs) play vital roles in virus-host interactions by regulating the expression of viral or host gene at posttranscriptional level. Our previous research showed that PRRSV infection down-regulates the expression of heme oxygenase-1 (HO-1), a pivotal cytoprotective enzyme, and overexpression of HO-1 inhibits PRRSV replication. In this study, we demonstrate that host miRNA miR-22 can downregulate HO-1 expression by directly targeting its 3' untranslated region. Suppression of HO-1 expression by miR-22 facilitates PRRSV replication. This work suggests that PRRSV may utilize cellular miRNA to modify antiviral host factor expression, enabling viral replication, which not only provides new insights into virus-host interactions during PRRSV infection, but also suggests potential therapies for PRRSV infection. PMID:27527787

  13. Canine parvovirus host range is determined by the specific conformation of an additional region of the capsid.

    PubMed Central

    Parker, J S; Parrish, C R

    1997-01-01

    We analyzed a region of the capsid of canine parvovirus (CPV) which determines the ability of the virus to infect canine cells. This region is distinct from those previously shown to determine the canine host range differences between CPV and feline panleukopenia virus. It lies on a ridge of the threefold spike of the capsid and is comprised of five interacting loops from three capsid protein monomers. We analyzed 12 mutants of CPV which contained amino acid changes in two adjacent loops exposed on the surface of this region. Nine mutants infected and grew in feline cells but were restricted in replication in one or the other of two canine cell lines tested. Three other mutants whose genomes contain mutations which affect one probable interchain bond were nonviable and could not be propagated in either canine or feline cells, although the VP1 and VP2 proteins from those mutants produced empty capsids when expressed from a plasmid vector. Although wild-type and mutant capsids bound to canine and feline cells in similar amounts, infection or viral DNA replication was greatly reduced after inoculation of canine cells with most of the mutants. The viral genomes of two host range-restricted mutants and two nonviable mutants replicated to wild-type levels in both feline and canine cells upon transfection with plasmid clones. The capsids of wild-type CPV and two mutants were similar in susceptibility to heat inactivation, but one of those mutants and one other were more stable against urea denaturation. Most mutations in this structural region altered the ability of monoclonal antibodies to recognize epitopes within a major neutralizing antigenic site, and that site could be subdivided into a number of distinct epitopes. These results argue that a specific structure of this region is required for CPV to retain its canine host range. PMID:9371580

  14. Macrophage Migration Inhibitory Factor Contributes to Host Defense against Acute Trypanosoma cruzi Infection

    PubMed Central

    Reyes, José L.; Terrazas, Luis I.; Espinoza, Bertha; Cruz-Robles, David; Soto, Virgilia; Rivera-Montoya, Irma; Gómez-García, Lorena; Snider, Heidi; Satoskar, Abhay R.; Rodríguez-Sosa, Miriam

    2006-01-01

    Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that is involved in the host defense against several pathogens. Here we used MIF−/− mice to determine the role of endogenous MIF in the regulation of the host immune response against Trypanosoma cruzi infection. MIF−/− mice displayed high levels of blood and tissue parasitemia, developed severe heart and skeletal muscle immunopathology, and succumbed to T. cruzi infection faster than MIF+/+ mice. The enhanced susceptibility of MIF−/− mice to T. cruzi was associated with reduced levels of proinflammatory cytokines, such as tumor necrosis factor alpha, interleukin-12 (IL-12), IL-18, gamma interferon (IFN-γ), and IL-1β, in their sera and reduced production of IL-12, IFN-γ, and IL-4 by spleen cells during the early phase of infection. At all time points, antigen-stimulated splenocytes from MIF+/+ and MIF−/− mice produced comparable levels of IL-10. MIF−/− mice also produced significantly less Th1-associated antigen-specific immunoglobulin G2a (IgG2a) throughout the infection, but both groups produced comparable levels of Th2-associated IgG1. Lastly, inflamed hearts from T. cruzi-infected MIF−/− mice expressed increased transcripts for IFN-γ, but fewer for IL-12 p35, IL-12 p40, IL-23, and inducible nitric oxide synthase, compared to MIF+/+ mice. Taken together, our findings show that MIF plays a role in controlling acute T. cruzi infection. PMID:16714544

  15. The gut microbiota composition in dichorionic triplet sets suggests a role for host genetic factors.

    PubMed

    Murphy, Kiera; O' Shea, Carol Anne; Ryan, C Anthony; Dempsey, Eugene M; O' Toole, Paul W; Stanton, Catherine; Ross, R Paul

    2015-01-01

    Monozygotic and dizygotic twin studies investigating the relative roles of host genetics and environmental factors in shaping gut microbiota composition have produced conflicting results. In this study, we investigated the gut microbiota composition of a healthy dichorionic triplet set. The dichorionic triplet set contained a pair of monozygotic twins and a fraternal sibling, with similar pre- and post-natal environmental conditions including feeding regime. V4 16S rRNA and rpoB amplicon pyrosequencing was employed to investigate microbiota composition, and the species and strain diversity of the culturable bifidobacterial population was also examined. At month 1, the monozygotic pair shared a similar microbiota distinct to the fraternal sibling. By month 12 however, the profile was more uniform between the three infants. Principal coordinate analysis (PCoA) of the microbiota composition revealed strong clustering of the monozygotic pair at month 1 and a separation of the fraternal infant. At months 2 and 3 the phylogenetic distance between the monozygotic pair and the fraternal sibling has greatly reduced and by month 12 the monozygotic pair no longer clustered separately from the fraternal infant. Pulse field gel electrophoresis (PFGE) analysis of the bifidobacterial population revealed a lack of strain diversity, with identical strains identified in all three infants at month 1 and 12. The microbiota of two antibiotic-treated dichorionic triplet sets was also investigated. Not surprisingly, in both triplet sets early life antibiotic administration appeared to be a major determinant of microbiota composition at month 1, irrespective of zygosity. By month 12, early antibiotic administration appeared to no longer exert such a strong influence on gut microbiota composition. We hypothesize that initially host genetics play a significant role in the composition of an individual's gut microbiota, unless an antibiotic intervention is given, but by month 12 environmental

  16. Highlights Regarding Host Predisposing Factors to Recurrent Vulvovaginal Candidiasis: Chronic Stress and Reduced Antioxidant Capacity.

    PubMed

    Akimoto-Gunther, Luciene; Bonfim-Mendonça, Patrícia de Souza; Takahachi, Gisele; Irie, Mary Mayumi T; Miyamoto, Sônia; Consolaro, Márcia Edilaine Lopes; Svidzinsk, Terezinha I Estivalet

    2016-01-01

    We studied host factors that could predispose women to develop recurrent vulvovaginal candidiasis (RVVC), including glycemia, insulin resistance, chronic stress, antioxidant capacity, overall immune status, local inflammation and vaginal microbiota. The presence of yeasts in vaginal culture was screened in 277 women, with or without signs and symptoms of VVC and RVVC. The presence of an inflammatory process and microbiota were analyzed through vaginal bacterioscopy and cervical-vaginal cytology, respectively. Fasting-blood samples were collected by standard venipuncture for biochemical analyses. Flow cytometry was employed to obtain the T helper/T cytotoxic lymphocyte ratio, and insulin resistance was assessed by the HOMA index (HI). Yeasts were isolated from 71 (26%) women: 23 (32.4%) with a positive culture but without symptoms (COL), 22 (31%) in an acute episode (VVC), and 26 (36.6%) with RVVC. C. albicans was the main yeast isolated in all clinical profiles. The control group (negative culture) comprised 206 women. Diabetes mellitus and insulin resistance were more associated with the positive-culture groups (COL, VVC and RVVC) than with negative ones. The RVVC group showed lower mean levels of cortisol than the control group and lower antioxidant capacity than all other groups. The T Helper/T cytotoxic lymphocyte ratio was similar in all groups. The RVVC group showed a similar level of vaginal inflammation to the control group, and lower than in the COL and VVC groups. Only the CVV group showed a reduction in vaginal lactobacillus microbiota. Our data suggest that both chronic stress (decreased early-morning cortisol levels) and reduced antioxidant capacity can be host predisposing factors to RVVC. PMID:27415762

  17. Highlights Regarding Host Predisposing Factors to Recurrent Vulvovaginal Candidiasis: Chronic Stress and Reduced Antioxidant Capacity

    PubMed Central

    Akimoto-Gunther, Luciene; Bonfim-Mendonça, Patrícia de Souza; Takahachi, Gisele; Irie, Mary Mayumi T.; Miyamoto, Sônia; Consolaro, Márcia Edilaine Lopes; Svidzinsk, Terezinha I. Estivalet

    2016-01-01

    We studied host factors that could predispose women to develop recurrent vulvovaginal candidiasis (RVVC), including glycemia, insulin resistance, chronic stress, antioxidant capacity, overall immune status, local inflammation and vaginal microbiota. The presence of yeasts in vaginal culture was screened in 277 women, with or without signs and symptoms of VVC and RVVC. The presence of an inflammatory process and microbiota were analyzed through vaginal bacterioscopy and cervical-vaginal cytology, respectively. Fasting-blood samples were collected by standard venipuncture for biochemical analyses. Flow cytometry was employed to obtain the T helper/T cytotoxic lymphocyte ratio, and insulin resistance was assessed by the HOMA index (HI). Yeasts were isolated from 71 (26%) women: 23 (32.4%) with a positive culture but without symptoms (COL), 22 (31%) in an acute episode (VVC), and 26 (36.6%) with RVVC. C. albicans was the main yeast isolated in all clinical profiles. The control group (negative culture) comprised 206 women. Diabetes mellitus and insulin resistance were more associated with the positive-culture groups (COL, VVC and RVVC) than with negative ones. The RVVC group showed lower mean levels of cortisol than the control group and lower antioxidant capacity than all other groups. The T Helper/T cytotoxic lymphocyte ratio was similar in all groups. The RVVC group showed a similar level of vaginal inflammation to the control group, and lower than in the COL and VVC groups. Only the CVV group showed a reduction in vaginal lactobacillus microbiota. Our data suggest that both chronic stress (decreased early-morning cortisol levels) and reduced antioxidant capacity can be host predisposing factors to RVVC. PMID:27415762

  18. New ex vivo reporter assay system reveals that σ factors of an unculturable pathogen control gene regulation involved in the host switching between insects and plants.

    PubMed

    Ishii, Yoshiko; Kakizawa, Shigeyuki; Oshima, Kenro

    2013-08-01

    Analysis of the environmental regulation of bacterial gene expression is important for understanding the nature, pathogenicity, and infection route of many pathogens. "Candidatus Phytoplasma asteris", onion yellows strain M (OY-M), is a phytopathogenic bacterium that is able to adapt to quite different host environments, including plants and insects, with a relatively small ~850 kb genome. The OY-M genome encodes two sigma (σ) factors, RpoD and FliA, that are homologous to Escherichia coli σ(70) and σ(28) , respectively. Previous studies show that gene expression of OY-M dramatically changes upon the response to insect and plant hosts. However, very little is known about the relationship between the two σ factors and gene regulatory systems in OY-M, because phytoplasma cannot currently be cultured in vitro. Here, we developed an Escherichia coli-based ex vivo reporter assay (EcERA) system to evaluate the transcriptional induction of phytoplasmal genes by the OY-M-derived σ factors. EcERA revealed that highly expressed genes in insect and plant hosts were regulated by RpoD and FliA, respectively. We also demonstrated that rpoD expression was significantly higher in insect than in plant hosts and fliA expression was similar between the hosts. These data indicate that phytoplasma-derived RpoD and FliA play key roles in the transcriptional switching mechanism during host switching between insects and plants. Our study will be invaluable to understand phytoplasmal transmission, virulence expression in plants, and the effect of infection on insect fitness. In addition, the novel EcERA system could be broadly applied to reveal transcriptional regulation mechanisms in other unculturable bacteria. PMID:23723081

  19. Bacteriophage Xp10 anti-termination factor p7 induces forward translocation by host RNA polymerase

    PubMed Central

    Zenkin, Nikolay; Severinov, Konstantin; Yuzenkova, Yulia

    2015-01-01

    Regulation of transcription elongation is based on response of RNA polymerase (RNAP) to various pause signals and is modulated by various accessory factors. Here we report that a 7 kDa protein p7 encoded by bacteriophage Xp10 acts as an elongation processivity factor of RNAP of host bacterium Xanthomonas oryzae, a major rice pathogen. Our data suggest that p7 stabilizes the upstream DNA duplex of the elongation complex thus disfavouring backtracking and promoting forward translocated states of the elongation complex. The p7-induced ‘pushing’ of RNAP and modification of RNAP contacts with the upstream edge of the transcription bubble lead to read-through of various types of pauses and termination signals and generally increase transcription processivity and elongation rate, contributing for transcription of an extremely long late genes operon of Xp10. Forward translocation was observed earlier upon the binding of unrelated bacterial elongation factor NusG, suggesting that this may be a general pathway of regulation of transcription elongation. PMID:26038312

  20. Regulatory network of microRNAs, target genes, transcription factors and host genes in endometrial cancer.

    PubMed

    Xue, Lu-Chen; Xu, Zhi-Wen; Wang, Kun-Hao; Wang, Ning; Zhang, Xiao-Xu; Wang, Shang

    2015-01-01

    Genes and microRNAs (miRNAs) have important roles in human oncology. However, most of the biological factors are reported in disperse form which makes it hard to discover the pathology. In this study, genes and miRNAs involved in human endometrial cancer(EC) were collected and formed into regulatory networks following their interactive relations, including miRNAs targeting genes, transcription factors (TFs) regulating miRNAs and miRNAs included in their host genes. Networks are constructed hierarchically at three levels: differentially expressed, related and global. Among the three, the differentially expressed network is the most important and fundamental network that contains the key genes and miRNAs in EC. The target genes, TFs and miRNAs are differentially expressed in EC so that any mutation in them may impact on EC development. Some key pathways in networks were highlighted to analyze how they interactively influence other factors and carcinogenesis. Upstream and downstream pathways of the differentially expressed genes and miRNAs were compared and analyzed. The purpose of this study was to partially reveal the deep regulatory mechanisms in EC using a new method that combines comprehensive genes and miRNAs together with their relationships. It may contribute to cancer prevention and gene therapy of EC. PMID:25684474

  1. 34 CFR 658.34 - What additional factors does the Secretary consider in selecting grant recipients?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... does the Secretary consider in selecting grant recipients? In addition to applying the selection criteria in, as appropriate §§ 658.31, 658.32, and 658.33, the Secretary, to the extent practicable and... 34 Education 3 2014-07-01 2014-07-01 false What additional factors does the Secretary consider...

  2. 34 CFR 658.34 - What additional factors does the Secretary consider in selecting grant recipients?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... does the Secretary consider in selecting grant recipients? In addition to applying the selection criteria in, as appropriate §§ 658.31, 658.32, and 658.33, the Secretary, to the extent practicable and... 34 Education 3 2013-07-01 2013-07-01 false What additional factors does the Secretary consider...

  3. 34 CFR 658.34 - What additional factors does the Secretary consider in selecting grant recipients?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... does the Secretary consider in selecting grant recipients? In addition to applying the selection criteria in, as appropriate §§ 658.31, 658.32, and 658.33, the Secretary, to the extent practicable and... 34 Education 3 2012-07-01 2012-07-01 false What additional factors does the Secretary consider...

  4. 34 CFR 658.34 - What additional factors does the Secretary consider in selecting grant recipients?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... does the Secretary consider in selecting grant recipients? In addition to applying the selection criteria in, as appropriate §§ 658.31, 658.32, and 658.33, the Secretary, to the extent practicable and... 34 Education 3 2011-07-01 2011-07-01 false What additional factors does the Secretary consider...

  5. Leptospira seroprevalence and associations between seropositivity, clinical disease and host factors in horses

    PubMed Central

    Båverud, V; Gunnarsson, A; Engvall, E Olsson; Franzén, P; Egenvall, A

    2009-01-01

    Background A cross-sectional study was carried out to determine the seroprevalence of different serovars of Leptospira spp. and their association with clinical disease and host factors in Swedish horses. Methods Sera from 2017 horses brought to equine clinics during 1997–98 were investigated. The sera were examined by microscopic agglutination test for the presence of antibodies against the following L. interrogans serovars: Bratislava strain Jez, Icterohaemorrhagiae strain Kantorowicz and Pomona strain Pomona and also L. kirschneri sv Grippotyphosa strain Duyster and L. borgpetersenii sv Sejroe strain M 84. Host factors, disease factors, season, pasture access and outdoor confinement variables were analysed with respect to seropositivity to sv Bratislava and Icterohaemorrhagiae. Multivariable logistic regression was used to model seropositivity to sv Bratislava and Icterohaemorrhagiae (seroprevalence > 8%). Results The seroprevalence, at a cut-off 1:100, were for sv Bratislava (16.6%), Icterohaemorrhagiae (8.3%), Sejroe (1.2%), Pomona (0.5%) and Grippotyphosa (0.4%). In the multivariable analysis, it was demonstrated that seroprevalence increased with age for sv Bratislava and Icterohaemorrhagiae. For sv Bratislava the seasons April – June and October – December and for sv Icterohaemorrhagiae October – December had higher seroprevalences than other seasons. Horses not used for racing had higher levels of seropositivity to sv Bratislava. Furthermore, horses with respiratory problems as well as horses with fatigue had higher levels of seropositivity to sv Bratislava. Ponies and coldbloods, and horses with access to pasture, had lower seroprevalence for sv Icterohaemorrhagiae. Healthy horses had lower seroprevalence for sv Icterohaemorrhagiae, than non-healthy horses. Conclusion There was no significant association between clinical signs and disease and positive titres to sv Bratislava (except for the association between respiratory problems and fatigue and

  6. Interaction of MYC with host cell factor-1 is mediated by the evolutionarily conserved Myc box IV motif.

    PubMed

    Thomas, L R; Foshage, A M; Weissmiller, A M; Popay, T M; Grieb, B C; Qualls, S J; Ng, V; Carboneau, B; Lorey, S; Eischen, C M; Tansey, W P

    2016-07-01

    The MYC family of oncogenes encodes a set of three related transcription factors that are overexpressed in many human tumors and contribute to the cancer-related deaths of more than 70,000 Americans every year. MYC proteins drive tumorigenesis by interacting with co-factors that enable them to regulate the expression of thousands of genes linked to cell growth, proliferation, metabolism and genome stability. One effective way to identify critical co-factors required for MYC function has been to focus on sequence motifs within MYC that are conserved throughout evolution, on the assumption that their conservation is driven by protein-protein interactions that are vital for MYC activity. In addition to their DNA-binding domains, MYC proteins carry five regions of high sequence conservation known as Myc boxes (Mb). To date, four of the Mb motifs (MbI, MbII, MbIIIa and MbIIIb) have had a molecular function assigned to them, but the precise role of the remaining Mb, MbIV, and the reason for its preservation in vertebrate Myc proteins, is unknown. Here, we show that MbIV is required for the association of MYC with the abundant transcriptional coregulator host cell factor-1 (HCF-1). We show that the invariant core of MbIV resembles the tetrapeptide HCF-binding motif (HBM) found in many HCF-interaction partners, and demonstrate that MYC interacts with HCF-1 in a manner indistinguishable from the prototypical HBM-containing protein VP16. Finally, we show that rationalized point mutations in MYC that disrupt interaction with HCF-1 attenuate the ability of MYC to drive tumorigenesis in mice. Together, these data expose a molecular function for MbIV and indicate that HCF-1 is an important co-factor for MYC. PMID:26522729

  7. Host-Specific Interactions with Environmental Factors Shape the Distribution of Symbiodinium across the Great Barrier Reef

    PubMed Central

    Tonk, Linda; Sampayo, Eugenia M.; Weeks, Scarla; Magno-Canto, Marites; Hoegh-Guldberg, Ove

    2013-01-01

    Background The endosymbiotic dinoflagellates (genus Symbiodinium) within coral reef invertebrates are critical to the survival of the holobiont. The genetic variability of Symbiodinium may contribute to the tolerance of the symbiotic association to elevated sea surface temperatures (SST). To assess the importance of factors such as the local environment, host identity and biogeography in driving Symbiodinium distributions on reef-wide scales, data from studies on reef invertebrate-Symbiodinium associations from the Great Barrier Reef (GBR) were compiled. Methodology/Principal Findings The resulting database consisted of 3717 entries from 26 studies. It was used to explore ecological patterns such as host-specificity and environmental drivers structuring community complexity using a multi-scalar approach. The data was analyzed in several ways: (i) frequently sampled host species were analyzed independently to investigate the influence of the environment on symbiont distributions, thereby excluding the influence of host specificity, (ii) host species distributions across sites were added as an environmental variable to determine the contribution of host identity on symbiont distribution, and (iii) data were pooled based on clade (broad genetic groups dividing the genus Symbiodinium) to investigate factors driving Symbiodinium distributions using lower taxonomic resolution. The results indicated that host species identity plays a dominant role in determining the distribution of Symbiodinium and environmental variables shape distributions on a host species-specific level. SST derived variables (especially SSTstdev) most often contributed to the selection of the best model. Clade level comparisons decreased the power of the predictive model indicating that it fails to incorporate the main drivers behind Symbiodinium distributions. Conclusions/Significance Including the influence of different host species on Symbiodinium distributional patterns improves our understanding

  8. New ex vivo reporter assay system reveals that σ factors of an unculturable pathogen control gene regulation involved in the host switching between insects and plants

    PubMed Central

    Ishii, Yoshiko; Kakizawa, Shigeyuki; Oshima, Kenro

    2013-01-01

    Abstract Analysis of the environmental regulation of bacterial gene expression is important for understanding the nature, pathogenicity, and infection route of many pathogens. “Candidatus Phytoplasma asteris”, onion yellows strain M (OY-M), is a phytopathogenic bacterium that is able to adapt to quite different host environments, including plants and insects, with a relatively small ∼850 kb genome. The OY-M genome encodes two sigma (σ) factors, RpoD and FliA, that are homologous to Escherichia coli σ70 and σ28, respectively. Previous studies show that gene expression of OY-M dramatically changes upon the response to insect and plant hosts. However, very little is known about the relationship between the two σ factors and gene regulatory systems in OY-M, because phytoplasma cannot currently be cultured in vitro. Here, we developed an Escherichia coli-based ex vivo reporter assay (EcERA) system to evaluate the transcriptional induction of phytoplasmal genes by the OY-M-derived σ factors. EcERA revealed that highly expressed genes in insect and plant hosts were regulated by RpoD and FliA, respectively. We also demonstrated that rpoD expression was significantly higher in insect than in plant hosts and fliA expression was similar between the hosts. These data indicate that phytoplasma-derived RpoD and FliA play key roles in the transcriptional switching mechanism during host switching between insects and plants. Our study will be invaluable to understand phytoplasmal transmission, virulence expression in plants, and the effect of infection on insect fitness. In addition, the novel EcERA system could be broadly applied to reveal transcriptional regulation mechanisms in other unculturable bacteria. Phytoplasma, an unculturable plant pathogen, could infect plant and insect cells, and dramatically changes their genes upon the response to these hosts. By a new system developed in this study, interactions between phytoplasma promoters and sigma factors were

  9. Chlamydia Infection Across Host Species Boundaries Promotes Distinct Sets of Transcribed Anti-Apoptotic Factors

    PubMed Central

    Messinger, Joshua E.; Nelton, Emmalin; Feeney, Colleen; Gondek, David C.

    2015-01-01

    Chlamydiae, obligate intracellular bacteria, cause significant human and veterinary associated diseases. Having emerged an estimated 700-million years ago, these bacteria have twice adapted to humans as a host species, causing sexually transmitted infection (C. trachomatis) and respiratory associated disease (C. pneumoniae). The principle mechanism of host cell defense against these intracellular bacteria is the induction of cell death via apoptosis. However, in the “arms race” of co-evolution, Chlamydiae have developed mechanisms to promote cell viability and inhibit cell death. Herein we examine the impact of Chlamydiae infection across multiple host species on transcription of anti-apoptotic genes. We found mostly distinct patterns of gene expression (Mcl1 and cIAPs) elicited by each pathogen-host pair indicating Chlamydiae infection across host species boundaries does not induce a universally shared host response. Understanding species specific host-pathogen interactions is paramount to deciphering how potential pathogens become emerging diseases. PMID:26779446

  10. Host and Bacterial Factors Involved in the Innate Ability of Mouse Macrophages To Eliminate Internalized Unopsonized Escherichia coli

    PubMed Central

    Hamrick, Terri S.; Havell, Edward A.; Horton, John R.; Orndorff, Paul E.

    2000-01-01

    In an effort to better understand genetic and cellular factors that influence innate immunity, we examined host and bacterial factors involved in the nonopsonic phagocytosis and killing of Escherichia coli K-12 by mouse macrophages. Unelicited (resident) peritoneal macrophages from five different mouse strains, BALB/c, C57BL/6, CD-1, C3H/HeJ, and C3H/HeN, were employed. Additional macrophage populations were obtained from CD-1 mice (bone marrow-derived macrophages). Also, for BALB/c and C57BL/6 mice, peritoneal macrophages elicited with either thioglycolate or proteose peptone, bone marrow-derived macrophages, and macrophage-like cell lines derived from the two strains were employed. Two E. coli K-12 strains that differed specifically in their abilities to produce type 1 pili containing the adhesive protein FimH were examined. The parameters used to assess macrophage bacteriocidal activity were (i) the killing of internalized (gentamicin-protected) E. coli during the approximately 4-h assay and (ii) the initial rate at which internalized E. coli were eliminated. Data on these parameters allowed the following conclusions: (i) unelicited or proteose peptone-elicited peritoneal macrophages were significantly better at eliminating internalized bacteria than thioglycolate-elicited peritoneal macrophages, bone marrow-derived macrophages, or macrophage cell lines; (ii) the host genetic background had no significant effect upon the ability of unelicited peritoneal macrophages to kill E. coli (even though the mouse strains differ widely in their in vivo susceptibilities to bacterial infection); and (iii) the FimH phenotype had no significant effect upon E. coli survival once the bacterium was inside a macrophage. Additionally, there was no correlation between the bacteriocidal effectiveness of a macrophage population and the number of bacteria bound per macrophage. However, macrophage populations that were the least bacteriocidal tended to bind higher ratios of FimH+ to Fim

  11. Propagation of pSC101 plasmids defective in binding of integration host factor.

    PubMed Central

    Biek, D P; Cohen, S N

    1992-01-01

    Integration host factor (IHF), a multifunctional protein of E. coli, normally is required for the replication of plasmid pSC101. T. T. Stenzel, P. Patel, and D. Bastia (Cell 49:709-717, 1987) have reported that IHF binds to a DNA locus near the pSC101 replication origin and enhances a static bend present in this region; mutation of the IHF binding site affects the plasmid's ability to replicate. We report here studies indicating that the requirement for IHF binding near the pSC101 replication origin is circumvented partially or completely by (i) mutation of the plasmid-encoded repA (replicase) gene or the chromosomally encoded topA gene, (ii) the presence on the plasmid of the pSC101 partition (par) locus, or (iii) replacement of the par locus by a strong transcriptional promoter. With the exception of the repA mutation, the factors that substitute for a functional origin region IHF binding site are known to alter plasmid topology by increasing negative DNA supercoiling, as does IHF itself. These results are consistent with the proposal that IHF binding near the pSC101 replication origin promotes plasmid replication by inducing a conformational change leading to formation of a repA-dependent DNA-protein complex. A variety of IHF-independent mechanisms can facilitate formation of the putative replication-initiation complex. PMID:1310092

  12. Host Genetic Risk Factors for West Nile Virus Infection and Disease Progression

    PubMed Central

    Bigham, Abigail W.; Buckingham, Kati J.; Husain, Sofia; Emond, Mary J.; Bofferding, Kathryn M.; Gildersleeve, Heidi; Rutherford, Ann; Astakhova, Natalia M.; Perelygin, Andrey A.; Busch, Michael P.; Murray, Kristy O.; Sejvar, James J.; Green, Sharone; Kriesel, John; Brinton, Margo A.; Bamshad, Michael

    2011-01-01

    West Nile virus (WNV), a category B pathogen endemic in parts of Africa, Asia and Europe, emerged in North America in 1999, and spread rapidly across the continental U.S. Outcomes of infection with WNV range from asymptomatic to severe neuroinvasive disease manifested as encephalitis, paralysis, and/or death. Neuroinvasive WNV disease occurs in less than one percent of cases, and although host genetic factors are thought to influence risk for symptomatic disease, the identity of these factors remains largely unknown. We tested 360 common haplotype tagging and/or functional SNPs in 86 genes that encode key regulators of immune function in 753 individuals infected with WNV including: 422 symptomatic WNV cases and 331 cases with asymptomatic infections. After applying a Bonferroni correction for multiple tests and controlling for population stratification, SNPs in IRF3 (OR 0.54, p = 0.035) and MX1, (OR 0.19, p = 0.014) were associated with symptomatic WNV infection and a single SNP in OAS1 (OR 9.79, p = 0.003) was associated with increased risk for West Nile encephalitis and paralysis (WNE/P). Together, these results suggest that genetic variation in the interferon response pathway is associated with both risk for symptomatic WNV infection and WNV disease progression. PMID:21935451

  13. Sphingosine kinase 2 is a chikungunya virus host factor co-localized with the viral replication complex

    PubMed Central

    Reid, St Patrick; Tritsch, Sarah R; Kota, Krishna; Chiang, Chih-Yuan; Dong, Lian; Kenny, Tara; Brueggemann, Ernest E; Ward, Michael D; Cazares, Lisa H; Bavari, Sina

    2015-01-01

    Chikungunya virus (CHIKV) is a re-emerging alphavirus which causes severe and prolonged arthralgic febrile illness. The recent global spread of the virus and lack of approved therapeutic options makes it imperative to gain greater insight into the molecular mechanisms underlying CHIKV pathogenesis, in particular host factors recruited by the virus. In the current study, we identify sphingosine kinase 2 (SK2) as a CHIKV host factor co-localized with the viral replication complex (VRC) during infection. SK2 was demonstrated to co-localize with viral RNA and nonstructural proteins. Targeted impairment of SK2 expression or function significantly inhibited CHIKV infection. Furthermore, affinity purification-mass spectrometry studies revealed that SK2 associates with a number of proteins involved in cellular gene expression specifically during viral infection, suggesting a role in replication. Collectively these results identify SK2 as a novel CHIKV host factor. PMID:26576339

  14. Are major behavioral and sociodemographic risk factors for mortality additive or multiplicative in their effects?

    PubMed

    Mehta, Neil; Preston, Samuel

    2016-04-01

    All individuals are subject to multiple risk factors for mortality. In this paper, we consider the nature of interactions between certain major sociodemographic and behavioral risk factors associated with all-cause mortality in the United States. We develop the formal logic pertaining to two forms of interaction between risk factors, additive and multiplicative relations. We then consider the general circumstances in which additive or multiplicative relations might be expected. We argue that expectations about interactions among socio-demographic variables, and their relation to behavioral variables, have been stated in terms of additivity. However, the statistical models typically used to estimate the relation between risk factors and mortality assume that risk factors act multiplicatively. We examine empirically the nature of interactions among five major risk factors associated with all-cause mortality: smoking, obesity, race, sex, and educational attainment. Data were drawn from the cross-sectional NHANES III (1988-1994) and NHANES 1999-2010 surveys, linked to death records through December 31, 2011. Our analytic sample comprised 35,604 respondents and 5369 deaths. We find that obesity is additive with each of the remaining four variables. We speculate that its additivity is a reflection of the fact that obese status is generally achieved later in life. For all pairings of socio-demographic variables, risks are multiplicative. For survival chances, it is much more dangerous to be poorly educated if you are black or if you are male. And it is much riskier to be a male if you are black. These traits, established at birth or during childhood, literally result in deadly combinations. We conclude that the identification of interactions among risk factors can cast valuable light on the nature of the process being studied. It also has public health implications by identifying especially vulnerable groups and by properly identifying the proportion of deaths

  15. The roles of host and pathogen factors and the innate immune response in the pathogenesis of Clostridium difficile infection

    PubMed Central

    Sun, Xingmin; Hirota, Simon A.

    2014-01-01

    Clostridium difficile (C. difficile) is the most common cause of nosocomial antibiotic-associated diarrhea and the etiologic agent of pseudomembranous colitis. The clinical manifestation of Clostridium difficile infection (CDI) is highly variable, from asymptomatic carriage, to mild self-limiting diarrhea, to the more severe pseudomembranous colitis. Furthermore, in extreme cases, colonic inflammation and tissue damage can lead to toxic megacolon, a condition requiring surgical intervention. C. difficile expresses two key virulence factors; the exotoxins, toxin A (TcdA) and toxin B (TcdB), which are glucosyltransferases that target host-cell monomeric GTPases. In addition, some hypervirulent strains produce a third toxin, binary toxin or C. difficile transferase (CDT), which may contribute to the pathogenesis of CDI. More recently, other factors such as surface layer proteins (SLPs) and flagellin have also been linked to the inflammatory responses observed in CDI. Although the adaptive immune response can influence the severity of CDI, the innate immune responses to C. difficile and its toxins play crucial roles in CDI onset, progression, and overall prognosis. Despite this, the innate immune responses in CDI have drawn relatively little attention from clinical researchers. Targeting these responses may prove useful clinically as adjuvant therapies, especially in refractory and/or recurrent CDI. This review will focus on recent advances in our understanding of how C. difficile and its toxins modulate innate immune responses that contribute to CDI pathogenesis. PMID:25242213

  16. The role of host genetic factors in respiratory tract infectious diseases: systematic review, meta-analyses and field synopsis

    PubMed Central

    Patarčić, Inga; Gelemanović, Andrea; Kirin, Mirna; Kolčić, Ivana; Theodoratou, Evropi; Baillie, Kenneth J.; de Jong, Menno D.; Rudan, Igor; Campbell, Harry; Polašek, Ozren

    2015-01-01

    Host genetic factors have frequently been implicated in respiratory infectious diseases, often with inconsistent results in replication studies. We identified 386 studies from the total of 24,823 studies identified in a systematic search of four bibliographic databases. We performed meta-analyses of studies on tuberculosis, influenza, respiratory syncytial virus, SARS-Coronavirus and pneumonia. One single-nucleotide polymorphism from IL4 gene was significant for pooled respiratory infections (rs2070874; 1.66 [1.29–2.14]). We also detected an association of TLR2 gene with tuberculosis (rs5743708; 3.19 [2.03–5.02]). Subset analyses identified CCL2 as an additional risk factor for tuberculosis (rs1024611; OR = 0.79 [0.72–0.88]). The IL4-TLR2-CCL2 axis could be a highly interesting target for translation towards clinical use. However, this conclusion is based on low credibility of evidence - almost 95% of all identified studies had strong risk of bias or confounding. Future studies must build upon larger-scale collaborations, but also strictly adhere to the highest evidence-based principles in study design, in order to reduce research waste and provide clinically translatable evidence. PMID:26524966

  17. Contribution of host-derived growth factors to in vivo growth of a transplantable murine mammary carcinoma.

    PubMed Central

    Davies, D. E.; Farmer, S.; White, J.; Senior, P. V.; Warnes, S. L.; Alexander, P.

    1994-01-01

    The contribution of host-derived growth factors to tumour growth in vivo was studied using the transplantable murine mammary carcinoma, MT1, grown in syngeneic mice. Promotion of growth of the mammary carcinoma by a factor(s) from the host was evident in experiments in which the carcinoma cells were inoculated intraperitoneally. In this environment, tumours develop as multiple solid nodules, each probably arising from an individual cell or a small cluster of cells. Tumour growth was found to occur in the peritoneal cavity following inoculation of 10(3) cells, but an inoculum of as few as ten cells grew if a leucocyte-rich exudate had first been induced. To determine which host-derived growth factors might contribute to growth of MT1, extracts of the tumour were first examined for growth factor activity. Fractionation of tumour extracts by either ion-exchange chromatography or gel filtration revealed several peaks of mitogenic activity, but none of this could be attributed to epidermal growth factor (EGF). Accordingly, an anti-EGF antibody was tested as a putative inhibitor of tumour growth as any effect of this antibody could be ascribed to removal of EGF derived from the host. The antibody was found to have potent anti-tumour activity when tested against MT1 tumours that had been inoculated into the peritoneal cavity. In contrast, the antibody had little effect on growth of the discrete tumour mass which formed when MT1 was transplanted subcutaneously. The results suggest that host-derived EGF contributes to establishment of microcolonies of MT1 carcinoma within the peritoneal cavity. This may be directly, by providing growth factors to supplement those produced by the tumour until it reaches a certain critical mass to sustain autocrine growth, or indirectly, by affecting the production of other growth-stimulatory factors or cytokines. PMID:8054274

  18. Propionibacterium acnes CAMP Factor and Host Acid Sphingomyelinase Contribute to Bacterial Virulence: Potential Targets for Inflammatory Acne Treatment

    PubMed Central

    Nakatsuji, Teruaki; Tang, De-chu C.; Zhang, Liangfang; Gallo, Richard L.; Huang, Chun-Ming

    2011-01-01

    Background In the progression of acne vulgaris, the disruption of follicular epithelia by an over-growth of Propionibacterium acnes (P. acnes) permits the bacteria to spread and become in contact with various skin and immune cells. Methodology/Principal Findings We have demonstrated in the present study that the Christie, Atkins, Munch-Peterson (CAMP) factor of P. acnes is a secretory protein with co-hemolytic activity with sphingomyelinase that can confer cytotoxicity to HaCaT keratinocytes and RAW264.7 macrophages. The CAMP factor from bacteria and acid sphingomyelinase (ASMase) from the host cells were simultaneously present in the culture supernatant only when the cells were co-cultured with P. acnes. Either anti-CAMP factor serum or desipramine, a selective ASMase inhibitor, significantly abrogated the P. acnes-induced cell death of HaCaT and RAW264.7 cells. Intradermal injection of ICR mouse ears with live P. acnes induced considerable ear inflammation, macrophage infiltration, and an increase in cellular soluble ASMase. Suppression of ASMase by systemic treatment with desipramine significantly reduced inflammatory reaction induced by intradermal injection with P. acnes, suggesting the contribution of host ASMase in P. acnes-induced inflammatory reaction in vivo. Vaccination of mice with CAMP factor elicited a protective immunity against P. acnes-induced ear inflammation, indicating the involvement of CAMP factor in P. acnes-induced inflammation. Most notably, suppression of both bacterial CAMP factor and host ASMase using vaccination and specific antibody injection, respectively, cooperatively alleviated P. acnes-induced inflammation. Conclusions/Significance These findings envision a novel infectious mechanism by which P. acnes CAMP factor may hijack host ASMase to amplify bacterial virulence to degrade and invade host cells. This work has identified both CAMP factor and ASMase as potential molecular targets for the development of drugs and vaccines against

  19. Natural and human induced factors influencing the abundance of Schistosoma host snails in Zambia.

    PubMed

    Monde, Concillia; Syampungani, Stephen; van den Brink, Paul J

    2016-06-01

    Schistosomiasis remains a global public health problem affecting about 240 million people. In Zambia, 2 million are infected while 3 million live with the risk of getting infected. Research and interventions relating to schistosomiasis are mainly linked to disease epidemiology. Malacological and ecological aspects of the disease are superficially understood. Developing effective control measures requires an understanding of interacting environmental and socioeconomic factors of host snails vis-a-vis schistosomiasis. Therefore, the present work involved collecting social and environmental data in a large field study in two zones in Zambia that are different in terms of temperature and rainfall amounts. Social data collected through questionnaires included demographic, educational and knowledge of schistosomiasis disease dynamics. Environmental data included physicochemical factors, aquatic plants and snails. Gender (P < 0.001) significantly influences livelihood strategies, while age (P = 0.069) and level of education (P = 0.086) have a moderate influence in zone I. In zone III, none of these factors (age, P = 0.378; gender, P = 0.311; education, P = 0.553) play a significant role. Environmental parameters explained 43 and 41 % variation in species composition for zones I and III, respectively. Most respondents' (52 %, 87 %) perception is that there are more cases of bilharzia in hot season than in other seasons (rainy season 23 %, 7 %; cold season 8 %, 0 % and year round 17 %, 6 %) for zone I and zone III, respectively. PMID:27230422

  20. The innate immune roles of host factors TRIM5α and Cyclophilin A on HIV-1 replication.

    PubMed

    Kuang, Yi-Qun; Liu, Hong-Liang; Zheng, Yong-Tang

    2015-10-01

    During the long-term evolutionary history, the interaction between virus and host has driven the first-line barrier, innate immunity, to invading pathogens. Innate immune factor TRIM5α and host peptidyl-prolyl cis-trans isomerase Cyclophilin A are two key players in the interaction between HIV-1 and host. Interestingly, Cyclophilin A is retrotransposed into the critical host gene, TRIM5, locus via LINE-1 element in some primate species including New World monkeys and Old World monkeys. This review aims to comprehensively discuss the sensing and immune activation procedures of TRIM5α innate signaling pathway through Cyclophilin A. It will then present the production of TRIMCyp chimeric gene and the different fusion patterns in primates. Finally, it will summarize the distinct restriction activity of TRIMCyp from different primates and explain the current understanding on the innate immune mechanisms involved in the early phase of the viral life cycle during HIV-1 replication. PMID:25894765

  1. Actin Recruitment to the Chlamydia Inclusion Is Spatiotemporally Regulated by a Mechanism That Requires Host and Bacterial Factors

    PubMed Central

    Chin, Elizabeth; Kirker, Kelly; Zuck, Meghan; James, Garth; Hybiske, Kevin

    2012-01-01

    The ability to exit host cells at the end of their developmental growth is a critical step for the intracellular bacterium Chlamydia. One exit strategy, extrusion, is mediated by host signaling pathways involved with actin polymerization. Here, we show that actin is recruited to the chlamydial inclusion as a late event, occurring after 20 hours post-infection (hpi) and only within a subpopulation of cells. This event increases significantly in prevalence and extent from 20 to 68 hpi, and actin coats strongly correlated with extrusions. In contrast to what has been reported for other intracellular pathogens, actin nucleation on Chlamydia inclusions did not ‘flash’, but rather exhibited moderate depolymerization dynamics. By using small molecule agents to selectively disrupt host signaling pathways involved with actin nucleation, modulate actin polymerization dynamics and also to disable the synthesis and secretion of chlamydial proteins, we further show that host and bacterial proteins are required for actin coat formation. Transient disruption of either host or bacterial signaling pathways resulted in rapid loss of coats in all infected cells and a reduction in extrusion formation. Inhibition of Chlamydia type III secretion also resulted in rapid loss of actin association on inclusions, thus implicating chlamydial effector proteins(s) as being central factors for engaging with host actin nucleating factors, such as formins. In conclusion, our data illuminate the host and bacterial driven process by which a dense actin matrix is dynamically nucleated and maintained on the Chlamydia inclusion. This late stage event is not ubiquitous for all infected cells in a population, and escalates in prevalence and extent throughout the developmental cycle of Chlamydia, culminating with their exit from the host cell by extrusion. The initiation of actin recruitment by Chlamydia appears to be novel, and may serve as an upstream determinant of the extrusion mechanism. PMID

  2. Individuality in gut microbiota composition is a complex polygenic trait shaped by multiple environmental and host genetic factors

    PubMed Central

    Benson, Andrew K.; Kelly, Scott A.; Legge, Ryan; Ma, Fangrui; Low, Soo Jen; Kim, Jaehyoung; Zhang, Min; Oh, Phaik Lyn; Nehrenberg, Derrick; Hua, Kunjie; Kachman, Stephen D.; Moriyama, Etsuko N.; Walter, Jens; Peterson, Daniel A.; Pomp, Daniel

    2010-01-01

    In vertebrates, including humans, individuals harbor gut microbial communities whose species composition and relative proportions of dominant microbial groups are tremendously varied. Although external and stochastic factors clearly contribute to the individuality of the microbiota, the fundamental principles dictating how environmental factors and host genetic factors combine to shape this complex ecosystem are largely unknown and require systematic study. Here we examined factors that affect microbiota composition in a large (n = 645) mouse advanced intercross line originating from a cross between C57BL/6J and an ICR-derived outbred line (HR). Quantitative pyrosequencing of the microbiota defined a core measurable microbiota (CMM) of 64 conserved taxonomic groups that varied quantitatively across most animals in the population. Although some of this variation can be explained by litter and cohort effects, individual host genotype had a measurable contribution. Testing of the CMM abundances for cosegregation with 530 fully informative SNP markers identified 18 host quantitative trait loci (QTL) that show significant or suggestive genome-wide linkage with relative abundances of specific microbial taxa. These QTL affect microbiota composition in three ways; some loci control individual microbial species, some control groups of related taxa, and some have putative pleiotropic effects on groups of distantly related organisms. These data provide clear evidence for the importance of host genetic control in shaping individual microbiome diversity in mammals, a key step toward understanding the factors that govern the assemblages of gut microbiota associated with complex diseases. PMID:20937875

  3. Human heme oxygenase 1 is a potential host cell factor against dengue virus replication

    PubMed Central

    Tseng, Chin-Kai; Lin, Chun-Kuang; Wu, Yu-Hsuan; Chen, Yen-Hsu; Chen, Wei-Chun; Young, Kung-Chia; Lee, Jin-Ching

    2016-01-01

    Dengue virus (DENV) infection and replication induces oxidative stress, which further contributes to the progression and pathogenesis of the DENV infection. Modulation of host antioxidant molecules may be a useful strategy for interfering with DENV replication. In this study, we showed that induction or exogenous overexpression of heme oxygenase-1 (HO-1), an antioxidant enzyme, effectively inhibited DENV replication in DENV-infected Huh-7 cells. This antiviral effect of HO-1 was attenuated by its inhibitor tin protoporphyrin (SnPP), suggesting that HO-1 was an important cellular factor against DENV replication. Biliverdin but not carbon monoxide and ferrous ions, which are products of the HO-1 on heme, mediated the HO-1-induced anti-DENV effect by non-competitively inhibiting DENV protease, with an inhibition constant (Ki) of 8.55 ± 0.38 μM. Moreover, HO-1 induction or its exogenous overexpression, rescued DENV-suppressed antiviral interferon response. Moreover, we showed that HO-1 induction by cobalt protoporphyrin (CoPP) and andrographolide, a natural product, as evidenced by a significant delay in the onset of disease and mortality, and virus load in the infected mice’s brains. These findings clearly revealed that a drug or therapy that induced the HO-1 signal pathway was a promising strategy for treating DENV infection. PMID:27553177

  4. Human heme oxygenase 1 is a potential host cell factor against dengue virus replication.

    PubMed

    Tseng, Chin-Kai; Lin, Chun-Kuang; Wu, Yu-Hsuan; Chen, Yen-Hsu; Chen, Wei-Chun; Young, Kung-Chia; Lee, Jin-Ching

    2016-01-01

    Dengue virus (DENV) infection and replication induces oxidative stress, which further contributes to the progression and pathogenesis of the DENV infection. Modulation of host antioxidant molecules may be a useful strategy for interfering with DENV replication. In this study, we showed that induction or exogenous overexpression of heme oxygenase-1 (HO-1), an antioxidant enzyme, effectively inhibited DENV replication in DENV-infected Huh-7 cells. This antiviral effect of HO-1 was attenuated by its inhibitor tin protoporphyrin (SnPP), suggesting that HO-1 was an important cellular factor against DENV replication. Biliverdin but not carbon monoxide and ferrous ions, which are products of the HO-1 on heme, mediated the HO-1-induced anti-DENV effect by non-competitively inhibiting DENV protease, with an inhibition constant (Ki) of 8.55 ± 0.38 μM. Moreover, HO-1 induction or its exogenous overexpression, rescued DENV-suppressed antiviral interferon response. Moreover, we showed that HO-1 induction by cobalt protoporphyrin (CoPP) and andrographolide, a natural product, as evidenced by a significant delay in the onset of disease and mortality, and virus load in the infected mice's brains. These findings clearly revealed that a drug or therapy that induced the HO-1 signal pathway was a promising strategy for treating DENV infection. PMID:27553177

  5. In vivo interaction of the Escherichia coli integration host factor with its specific binding sites.

    PubMed

    Engelhorn, M; Boccard, F; Murtin, C; Prentki, P; Geiselmann, J

    1995-08-11

    The histone-like protein integration host factor (IHF) of Escherichia coli binds to specific binding sites on the chromosome or on mobile genetic elements, and is involved in many cellular processes. We have analyzed the interaction of IHF with five different binding sites in vitro and in vivo using UV laser footprinting, a technique that probes the immediate environment and conformation of a segment of DNA. Using this generally applicable technique we can directly compare the binding modes and interaction strengths of a DNA binding protein in its physiological environment within the cell to measurements performed in vitro. We conclude that the interactions between IHF and its specific binding sites are identical in vitro and in vivo. The footprinting signal is consistent with the model of IHF-binding to DNA proposed by Yang and Nash (1989). The occupancy of binding sites varies with the concentration of IHF in the cell and allows to estimate the concentration of free IHF protein in the cell. PMID:7659518

  6. In vivo interaction of the Escherichia coli integration host factor with its specific binding sites.

    PubMed

    Engelhorn, M; Boccard, F; Murtin, C; Prentki, P; Geiselmann, J

    1995-09-11

    The histone-like protein integration host factor (IHF) of Escherichia coli binds to specific binding sites on the chromosome or on mobile genetic elements, and is involved in many cellular processes. We have analyzed the interaction of IHF with five different binding sites in vitro and in vivo using UV laser footprinting, a technique that probes the immediate environment and conformation of a segment of DNA. Using this generally applicable technique we can directly compare the binding modes and interaction strengths of a DNA binding protein in its physiological environment within the cell to measurements performed in vitro. We conclude that the interactions between IHF and its specific binding sites are identical in vitro and in vivo. The footprinting signal is consistent with the model of IHF-binding to DNA proposed by Yang and Nash (1989). The occupancy of binding sites varies with the concentration of IHF in the cell and allows to estimate the concentration of free IHF protein in the cell. PMID:7567442

  7. A Chromosomally Encoded Virulence Factor Protects the Lyme Disease Pathogen against Host-Adaptive Immunity

    PubMed Central

    Yang, Xiuli; Coleman, Adam S.; Anguita, Juan; Pal, Utpal

    2009-01-01

    Borrelia burgdorferi, the bacterial pathogen of Lyme borreliosis, differentially expresses select genes in vivo, likely contributing to microbial persistence and disease. Expression analysis of spirochete genes encoding potential membrane proteins showed that surface-located membrane protein 1 (lmp1) transcripts were expressed at high levels in the infected murine heart, especially during early stages of infection. Mice and humans with diagnosed Lyme borreliosis also developed antibodies against Lmp1. Deletion of lmp1 severely impaired the pathogen's ability to persist in diverse murine tissues including the heart, and to induce disease, which was restored upon chromosomal complementation of the mutant with the lmp1 gene. Lmp1 performs an immune-related rather than a metabolic function, as its deletion did not affect microbial persistence in immunodeficient mice, but significantly decreased spirochete resistance to the borreliacidal effects of anti-B. burgdorferi sera in a complement-independent manner. These data demonstrate the existence of a virulence factor that helps the pathogen evade host-acquired immune defense and establish persistent infection in mammals. PMID:19266024

  8. Tumor necrosis factor-alpha deficiency impairs host defense against Streptococcus pneumoniae

    PubMed Central

    Jeong, Dong-Gu; Seo, Jin-Hee; Heo, Seung-Ho; Choi, Yang-Kyu

    2015-01-01

    Streptococcus pneumoniae is a major human pathogen that is involved in community-acquired pneumonia. Tumor necrosis factor-alpha (TNF-α) is a pro-inflammatory cytokine that activates immune responses against infection, invasion, injury, or inflammation. To study the role of TNF-α during S. pneumoniae infection, a murine pneumococcal pneumonia model was used. We intranasally infected C57BL/6J wild-type (WT) and TNF-α knockout (KO) mice with S. pneumoniae D39 serotype 2. In TNF-α KO mice, continuous and distinct loss of body weight, and low survival rates were observed. Bacterial counts in the lungs and blood of TNF-α KO mice were significantly higher than those in WT mice. Histopathological lesions in the spleen of TNF-α KO mice were more severe than those in WT mice. In TNF-α KO mice, severe depletion of white pulp was observed and the number of apoptotic cells was significantly increased. Interferon-gamma (IFN-γ), IL-12p70 and IL-10 levels in serum were significantly increased in TNF-α KO mice. TNF-α is clearly involved in the regulation of S. pneumoniae infections. Early death and low survival rates of TNF-α KO mice were likely caused by a combination of impaired bacterial clearance and damage to the spleen. Our findings suggest that TNF-α plays a critical role in protecting the host from systemic S. pneumoniae infection. PMID:26155202

  9. Host Transmission of Salmonella enterica Serovar Typhimurium Is Controlled by Virulence Factors and Indigenous Intestinal Microbiota▿

    PubMed Central

    Lawley, Trevor D.; Bouley, Donna M.; Hoy, Yana E.; Gerke, Christine; Relman, David A.; Monack, Denise M.

    2008-01-01

    Transmission is an essential stage of a pathogen's life cycle and remains poorly understood. We describe here a model in which persistently infected 129X1/SvJ mice provide a natural model of Salmonella enterica serovar Typhimurium transmission. In this model only a subset of the infected mice, termed supershedders, shed high levels (>108 CFU/g) of Salmonella serovar Typhimurium in their feces and, as a result, rapidly transmit infection. While most Salmonella serovar Typhimurium-infected mice show signs of intestinal inflammation, only supershedder mice develop colitis. Development of the supershedder phenotype depends on the virulence determinants Salmonella pathogenicity islands 1 and 2, and it is characterized by mucosal invasion and, importantly, high luminal abundance of Salmonella serovar Typhimurium within the colon. Immunosuppression of infected mice does not induce the supershedder phenotype, demonstrating that the immune response is not the main determinant of Salmonella serovar Typhimurium levels within the colon. In contrast, treatment of mice with antibiotics that alter the health-associated indigenous intestinal microbiota rapidly induces the supershedder phenotype in infected mice and predisposes uninfected mice to the supershedder phenotype for several days. These results demonstrate that the intestinal microbiota plays a critical role in controlling Salmonella serovar Typhimurium infection, disease, and transmissibility. This novel model should facilitate the study of host, pathogen, and intestinal microbiota factors that contribute to infectious disease transmission. PMID:17967858

  10. Identification of Burkholderia cenocepacia Strain H111 Virulence Factors Using Nonmammalian Infection Hosts

    PubMed Central

    Schwager, Stephan; Agnoli, Kirsty; Köthe, Manuela; Feldmann, Friederike; Givskov, Michael; Carlier, Aurelien

    2013-01-01

    Burkholderia cenocepacia H111, a strain isolated from a cystic fibrosis patient, has been shown to effectively kill the nematode Caenorhabditis elegans. We used the C. elegans model of infection to screen a mini-Tn5 mutant library of B. cenocepacia H111 for attenuated virulence. Of the approximately 5,500 B. cenocepacia H111 random mini-Tn5 insertion mutants that were screened, 22 showed attenuated virulence in C. elegans. Except for the quorum-sensing regulator cepR, none of the mutated genes coded for the biosynthesis of classical virulence factors such as extracellular proteases or siderophores. Instead, the mutants contained insertions in metabolic and regulatory genes. Mutants attenuated in virulence in the C. elegans infection model were also tested in the Drosophila melanogaster pricking model, and those also attenuated in this model were further tested in Galleria mellonella. Six of the 22 mutants were attenuated in D. melanogaster, and five of these were less pathogenic in the G. mellonella model. We show that genes encoding enzymes of the purine, pyrimidine, and shikimate biosynthesis pathways are critical for virulence in multiple host models of infection. PMID:23090963

  11. TARGETING BACTERIAL INTEGRATION HOST FACTOR TO DISRUPT BIOFILMS ASSOCIATED WITH CYSTIC FIBROSIS

    PubMed Central

    Gustave, Jodi E.; Jurcisek, Joseph A.; McCoy, Karen S.; Goodman, Steven D.; Bakaletz, Lauren O.

    2012-01-01

    Background Identify whether the bacterial protein, Integration Host Factor (IHF), is present within sputum solids collected from Cystic Fibrosis (CF) patients and thus might contribute to the structural stability of biofilms within the lungs. Methods The presence of IHF in sputum was determined by immunohistochemistry. The role of IHF in stabilizing biofilms within sputum was tested in vitro wherein anti-IHF was used to attempt to dissolve sputum solids. Results Thirty-seven of 44 sputum samples (84%) were positive for anti-IHF staining. Treatment with anti-IHF or DNase of 6 representative samples, dissolved sputum solids significantly better than treatment with normal saline in vitro, and strong synergism was observed when these agents were used in combination. Conclusions IHF was detected in the majority of sputum samples from patients with CF and in vitro treatment with anti-IHF induced dissolution of sputum solids. These data support further investigation of IHF as a potential therapeutic target for patients with CF. PMID:23168017

  12. Host Genetic Factors Associated with Symptomatic Primary HIV Infection and Disease Progression among Argentinean Seroconverters

    PubMed Central

    Coloccini, Romina Soledad; Dilernia, Dario; Ghiglione, Yanina; Turk, Gabriela; Laufer, Natalia; Rubio, Andrea; Socías, María Eugenia; Figueroa, María Inés; Sued, Omar; Cahn, Pedro; Salomón, Horacio; Mangano, Andrea; Pando, María Ángeles

    2014-01-01

    Background Variants in HIV-coreceptor C-C chemokine receptor type 5 (CCR5) and Human leukocyte antigen (HLA) genes are the most important host genetic factors associated with HIV infection and disease progression. Our aim was to analyze the association of these genetic factors in the presence of clinical symptoms during Primary HIV Infection (PHI) and disease progression within the first year. Methods Seventy subjects diagnosed during PHI were studied (55 symptomatic and 15 asymptomatic). Viral load (VL) and CD4 T-cell count were evaluated. HIV progression was defined by presence of B or C events and/or CD4 T-cell counts <350 cell/mm3. CCR5 haplotypes were characterized by polymerase chain reaction and SDM-PCR-RFLP. HLA-I characterization was performed by Sequencing. Results Symptoms during PHI were significantly associated with lower frequency of CCR5-CF1 (1.8% vs. 26.7%, p = 0.006). Rapid progression was significantly associated with higher frequency of CCR5-CF2 (16.7% vs. 0%, p = 0.024) and HLA-A*11 (16.7% vs. 1.2%, p = 0.003) and lower frequency of HLA-C*3 (2.8% vs. 17.5%, p = 0.035). Higher baseline VL was significantly associated with presence of HLA-A*11, HLA-A*24, and absence of HLA-A*31 and HLA-B*57. Higher 6-month VL was significantly associated with presence of CCR5-HHE, HLA-A*24, HLA-B*53, and absence of HLA-A*31 and CCR5-CF1. Lower baseline CD4 T-cell count was significantly associated with presence of HLA-A*24/*33, HLA-B*53, CCR5-CF2 and absence of HLA-A*01/*23 and CCR5-HHA. Lower 6-month CD4 T-cell count was associated with presence of HLA-A*24 and HLA-B*53, and absence of HLA-A*01 and HLA-B*07/*39. Moreover, lower 12-month CD4 T-cell count was significantly associated with presence of HLA-A*33, HLA-B*14, HLA-C*08, CCR5-CF2, and absence of HLA-B*07 and HLA-C*07. Conclusion Several host factors were significantly associated with disease progression in PHI subjects. Most results agree with previous studies performed in other groups

  13. M062 Is a Host Range Factor Essential for Myxoma Virus Pathogenesis and Functions as an Antagonist of Host SAMD9 in Human Cells▿ †

    PubMed Central

    Liu, Jia; Wennier, Sonia; Zhang, Leiliang; McFadden, Grant

    2011-01-01

    Myxoma virus (MYXV) M062R is a functional homolog of the C7L family of host range genes from orthopoxviruses. We constructed a targeted M062R-knockout-MYXV (vMyxM062-KO) and characterized its properties in vitro and in vivo. In European rabbits, infection by vMyxM062-KO was completely asymptomatic. The surviving rabbits did not gain full protection against the subsequent lethal-dose challenge with wild-type MYXV. We also looked for cellular tropism defects in a variety of cultured cells. In all of the rabbit cells tested, vMyxM062-KO conducts an abortive infection, although it initiates viral DNA replication. In many, but not all, human cancer cells that are permissive for wild-type MYXV, vMyxM062-KO exhibited a profound replication defect. We categorized human cells tested into two groups: (i) type A, which support productive replication for wild-type MYXV but are unable to produce significant levels of progeny virus by vMyxM062-KO, and (ii) type B, which are permissive to infections by both wild-type MYXV and vMyxM062-KO. Furthermore, using proteomic strategies, we identified sterile α motif domain containing 9 (SAMD9), an interferon-regulated cellular protein implicated in human inflammatory disorders, as a unique host binding partner of M062 in human cells. Significantly, knocking down SAMD9 in type A human cancer cells led to a substantial rescue of vMyxM062-KO infection. In summary, M062 is a novel host range factor that controls productive MYXV replication in rabbit cells and in a wide variety of human cells. M062 also binds and antagonizes cellular SAMD9 in human cells, suggesting that SAMD9 is a novel innate antiviral factor against poxviruses. PMID:21248034

  14. Decoding Biomass-Sensing Regulons of Clostridium thermocellum Alternative Sigma-I Factors in a Heterologous Bacillus subtilis Host System

    PubMed Central

    Rozman Grinberg, Inna; Garty, Yuval; Bayer, Edward A.; Shoham, Yuval; Lamed, Raphael; Borovok, Ilya

    2016-01-01

    The Gram-positive, anaerobic, cellulolytic, thermophile Clostridium (Ruminiclostridium) thermocellum secretes a multi-enzyme system called the cellulosome to solubilize plant cell wall polysaccharides. During the saccharolytic process, the enzymatic composition of the cellulosome is modulated according to the type of polysaccharide(s) present in the environment. C. thermocellum has a set of eight alternative RNA polymerase sigma (σ) factors that are activated in response to extracellular polysaccharides and share sequence similarity to the Bacillus subtilis σI factor. The aim of the present work was to demonstrate whether individual C. thermocellum σI-like factors regulate specific cellulosomal genes, focusing on C. thermocellum σI6 and σI3 factors. To search for putative σI6- and σI3-dependent promoters, bioinformatic analysis of the upstream regions of the cellulosomal genes was performed. Because of the limited genetic tools available for C. thermocellum, the functionality of the predicted σI6- and σI3-dependent promoters was studied in B. subtilis as a heterologous host. This system enabled observation of the activation of 10 predicted σI6-dependent promoters associated with the C. thermocellum genes: sigI6 (itself, Clo1313_2778), xyn11B (Clo1313_0522), xyn10D (Clo1313_0177), xyn10Z (Clo1313_2635), xyn10Y (Clo1313_1305), cel9V (Clo1313_0349), cseP (Clo1313_2188), sigI1 (Clo1313_2174), cipA (Clo1313_0627), and rsgI5 (Clo1313_0985). Additionally, we observed the activation of 4 predicted σI3-dependent promoters associated with the C. thermocellum genes: sigI3 (itself, Clo1313_1911), pl11 (Clo1313_1983), ce12 (Clo1313_0693) and cipA. Our results suggest possible regulons of σI6 and σI3 in C. thermocellum, as well as the σI6 and σI3 promoter consensus sequences. The proposed -35 and -10 promoter consensus elements of σI6 are CNNAAA and CGAA, respectively. Additionally, a less conserved CGA sequence next to the C in the -35 element and a highly

  15. Decoding Biomass-Sensing Regulons of Clostridium thermocellum Alternative Sigma-I Factors in a Heterologous Bacillus subtilis Host System.

    PubMed

    Muñoz-Gutiérrez, Iván; Ortiz de Ora, Lizett; Rozman Grinberg, Inna; Garty, Yuval; Bayer, Edward A; Shoham, Yuval; Lamed, Raphael; Borovok, Ilya

    2016-01-01

    The Gram-positive, anaerobic, cellulolytic, thermophile Clostridium (Ruminiclostridium) thermocellum secretes a multi-enzyme system called the cellulosome to solubilize plant cell wall polysaccharides. During the saccharolytic process, the enzymatic composition of the cellulosome is modulated according to the type of polysaccharide(s) present in the environment. C. thermocellum has a set of eight alternative RNA polymerase sigma (σ) factors that are activated in response to extracellular polysaccharides and share sequence similarity to the Bacillus subtilis σI factor. The aim of the present work was to demonstrate whether individual C. thermocellum σI-like factors regulate specific cellulosomal genes, focusing on C. thermocellum σI6 and σI3 factors. To search for putative σI6- and σI3-dependent promoters, bioinformatic analysis of the upstream regions of the cellulosomal genes was performed. Because of the limited genetic tools available for C. thermocellum, the functionality of the predicted σI6- and σI3-dependent promoters was studied in B. subtilis as a heterologous host. This system enabled observation of the activation of 10 predicted σI6-dependent promoters associated with the C. thermocellum genes: sigI6 (itself, Clo1313_2778), xyn11B (Clo1313_0522), xyn10D (Clo1313_0177), xyn10Z (Clo1313_2635), xyn10Y (Clo1313_1305), cel9V (Clo1313_0349), cseP (Clo1313_2188), sigI1 (Clo1313_2174), cipA (Clo1313_0627), and rsgI5 (Clo1313_0985). Additionally, we observed the activation of 4 predicted σI3-dependent promoters associated with the C. thermocellum genes: sigI3 (itself, Clo1313_1911), pl11 (Clo1313_1983), ce12 (Clo1313_0693) and cipA. Our results suggest possible regulons of σI6 and σI3 in C. thermocellum, as well as the σI6 and σI3 promoter consensus sequences. The proposed -35 and -10 promoter consensus elements of σI6 are CNNAAA and CGAA, respectively. Additionally, a less conserved CGA sequence next to the C in the -35 element and a highly

  16. Host Immunological Factors Enhancing Mortality of Young Adults during the 1918 Influenza Pandemic

    PubMed Central

    McAuley, Julie L.; Kedzierska, Katherine; Brown, Lorena E.; Shanks, G. Dennis

    2015-01-01

    During the 1918 influenza pandemic, healthy young adults unusually succumbed to infection and were considered more vulnerable than young children and the elderly. The pathogenesis of this pandemic in the young adult population remains poorly understood. As this population is normally the least likely to die during seasonal influenza outbreaks, thought to be due to their appropriate pre-existing and robust immune responses protecting them from infection, we sought to review existing literature for immunological reasons for excessive mortality during the 1918 pandemic. We propose the novelty of the H1N1 pandemic virus to an H1N1 naïve immune system, the virulence of this virus, and dysfunctional host inflammatory and immunological responses, shaped by past influenza infections could have each contributed to their overall susceptibility. Additionally, in the young adult population, pre-exposure to past influenza infection of different subtypes, such as a H3N8 virus, during their infancy in 1889–1892, may have shaped immunological responses and enhanced vulnerability via humoral immunity effects with cross-reactive or non-neutralizing antibodies; excessive and/or ineffective cellular immunity from memory T lymphocytes; and innate dysfunctional inflammation. Multiple mechanisms likely contributed to the increased young adult mortality in 1918 and are the focus of this review. PMID:26347742

  17. More than Meets the Ear: A Factor Analysis of Student Impressions of Television Talk Show Hosts.

    ERIC Educational Resources Information Center

    Walker, James R.

    To identify the descriptors most frequently associated with four popular television talk show hosts and to isolate the fundamental dimensions of the images of those talk show hosts, a study surveyed 209 students from Memphis State University and the University of Arkansas (Little Rock) about their impressions of Johnny Carson, David Letterman,…

  18. 34 CFR 658.34 - What additional factors does the Secretary consider in selecting grant recipients?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 3 2010-07-01 2010-07-01 false What additional factors does the Secretary consider in selecting grant recipients? 658.34 Section 658.34 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION UNDERGRADUATE...

  19. 34 CFR 655.32 - What additional factors does the Secretary consider in making grant awards?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION INTERNATIONAL EDUCATION... Secretary consider in making grant awards? Except for 34 CFR parts 656, 657, and 661, to the extent... 34 Education 3 2010-07-01 2010-07-01 false What additional factors does the Secretary consider...

  20. 34 CFR 490.22 - What additional factor does the Secretary consider?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 3 2010-07-01 2010-07-01 false What additional factor does the Secretary consider? 490.22 Section 490.22 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION LIFE SKILLS FOR STATE AND...

  1. 34 CFR 411.22 - What additional factors may the Secretary consider?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 34 Education 3 2013-07-01 2013-07-01 false What additional factors may the Secretary consider? 411.22 Section 411.22 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION VOCATIONAL EDUCATION RESEARCH...

  2. 34 CFR 401.22 - What additional factors may the Secretary consider?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 34 Education 3 2014-07-01 2014-07-01 false What additional factors may the Secretary consider? 401.22 Section 401.22 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION INDIAN VOCATIONAL EDUCATION PROGRAM...

  3. 34 CFR 401.22 - What additional factors may the Secretary consider?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 3 2010-07-01 2010-07-01 false What additional factors may the Secretary consider? 401.22 Section 401.22 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION INDIAN VOCATIONAL EDUCATION PROGRAM...

  4. 34 CFR 401.22 - What additional factors may the Secretary consider?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 34 Education 3 2013-07-01 2013-07-01 false What additional factors may the Secretary consider? 401.22 Section 401.22 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION INDIAN VOCATIONAL EDUCATION PROGRAM...

  5. 34 CFR 411.22 - What additional factors may the Secretary consider?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 3 2010-07-01 2010-07-01 false What additional factors may the Secretary consider? 411.22 Section 411.22 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION VOCATIONAL EDUCATION RESEARCH...

  6. 34 CFR 411.22 - What additional factors may the Secretary consider?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 34 Education 3 2011-07-01 2011-07-01 false What additional factors may the Secretary consider? 411.22 Section 411.22 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION VOCATIONAL EDUCATION RESEARCH...

  7. 34 CFR 401.22 - What additional factors may the Secretary consider?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 34 Education 3 2012-07-01 2012-07-01 false What additional factors may the Secretary consider? 401.22 Section 401.22 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION INDIAN VOCATIONAL EDUCATION PROGRAM...

  8. 34 CFR 411.22 - What additional factors may the Secretary consider?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 34 Education 3 2012-07-01 2012-07-01 false What additional factors may the Secretary consider? 411.22 Section 411.22 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION VOCATIONAL EDUCATION RESEARCH...

  9. 34 CFR 401.22 - What additional factors may the Secretary consider?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 34 Education 3 2011-07-01 2011-07-01 false What additional factors may the Secretary consider? 401.22 Section 401.22 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION INDIAN VOCATIONAL EDUCATION PROGRAM...

  10. 34 CFR 411.22 - What additional factors may the Secretary consider?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 34 Education 3 2014-07-01 2014-07-01 false What additional factors may the Secretary consider? 411.22 Section 411.22 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION VOCATIONAL EDUCATION RESEARCH...

  11. 34 CFR 472.23 - What additional factor does the Secretary consider?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 34 Education 3 2012-07-01 2012-07-01 false What additional factor does the Secretary consider? 472.23 Section 472.23 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION NATIONAL WORKPLACE LITERACY PROGRAM...

  12. 34 CFR 472.23 - What additional factor does the Secretary consider?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 34 Education 3 2014-07-01 2014-07-01 false What additional factor does the Secretary consider? 472.23 Section 472.23 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION NATIONAL WORKPLACE LITERACY PROGRAM...

  13. 34 CFR 472.23 - What additional factor does the Secretary consider?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 34 Education 3 2011-07-01 2011-07-01 false What additional factor does the Secretary consider? 472.23 Section 472.23 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION NATIONAL WORKPLACE LITERACY PROGRAM...

  14. 34 CFR 472.23 - What additional factor does the Secretary consider?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 3 2010-07-01 2010-07-01 false What additional factor does the Secretary consider? 472.23 Section 472.23 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION NATIONAL WORKPLACE LITERACY PROGRAM...

  15. 34 CFR 472.23 - What additional factor does the Secretary consider?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 34 Education 3 2013-07-01 2013-07-01 false What additional factor does the Secretary consider? 472.23 Section 472.23 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION NATIONAL WORKPLACE LITERACY PROGRAM...

  16. 34 CFR 655.32 - What additional factors does the Secretary consider in making grant awards?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... PROGRAMS-GENERAL PROVISIONS How Does the Secretary Make a Grant? § 655.32 What additional factors does the Secretary consider in making grant awards? Except for 34 CFR parts 656, 657, and 661, to the extent... making grant awards? 655.32 Section 655.32 Education Regulations of the Offices of the Department...

  17. 34 CFR 655.32 - What additional factors does the Secretary consider in making grant awards?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... PROGRAMS-GENERAL PROVISIONS How Does the Secretary Make a Grant? § 655.32 What additional factors does the Secretary consider in making grant awards? Except for 34 CFR parts 656, 657, and 661, to the extent... making grant awards? 655.32 Section 655.32 Education Regulations of the Offices of the Department...

  18. 34 CFR 655.32 - What additional factors does the Secretary consider in making grant awards?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... PROGRAMS-GENERAL PROVISIONS How Does the Secretary Make a Grant? § 655.32 What additional factors does the Secretary consider in making grant awards? Except for 34 CFR parts 656, 657, and 661, to the extent... making grant awards? 655.32 Section 655.32 Education Regulations of the Offices of the Department...

  19. 34 CFR 655.32 - What additional factors does the Secretary consider in making grant awards?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 34 Education 3 2014-07-01 2014-07-01 false What additional factors does the Secretary consider in making grant awards? 655.32 Section 655.32 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION INTERNATIONAL EDUCATION PROGRAMS-GENERAL PROVISIONS How Does...

  20. 34 CFR 477.22 - What additional factors does the Secretary consider?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 3 2010-07-01 2010-07-01 false What additional factors does the Secretary consider? 477.22 Section 477.22 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION STATE PROGRAM ANALYSIS ASSISTANCE...

  1. MTHFR homozygous mutation and additional risk factors for cerebral infarction in a large Italian family.

    PubMed

    Del Balzo, Francesca; Spalice, Alberto; Perla, Massimo; Properzi, Enrico; Iannetti, Paola

    2009-01-01

    Several cases with cerebral infarctions associated with the C677T mutation in the methylenetetrahydrofolate reductase gene (MTHFR) have been reported. Given the large number of asymptomatic individuals with the MTHFR mutation, additional risk factors for cerebral infarction should be considered. This study describes a large family with the MTHFR mutation and a combination of heterozygous factor V Leiden mutations and different additional exogenous and endogenous thrombogenic risk factors. Psychomotor retardation and a left fronto-insular infarct associated with the MTHFR mutation together with diminished factor VII and low level of protein C was documented in the first patient. In the second patient, generalized epilepsy and a malacic area in the right nucleus lenticularis was associated with the MTHFR mutation and a low level of protein C. In the third patient, right hemiparesis and a left fronto-temporal porencephalic cyst were documented, together with the MTHFR mutation and hyperhomocysteinemia. An extensive search of additional circumstantial and genetic thrombogenic risk factors should be useful for prophylaxis and prognosis of infants with cerebral infarctions associated with the MTHFR mutation and of their related family members. PMID:19068258

  2. Pathogenesis mediated by proviral host factors involved in translation and replication of plant positive-strand RNA viruses.

    PubMed

    Hyodo, Kiwamu; Okuno, Tetsuro

    2016-04-01

    Viral pathogenesis comes from complex interactions between viruses and hosts. All the processes of viral infection, including translation of viral factors and replication of viral genomes, define viral pathogenesis; therefore, molecular insights into the mechanisms underlying viral replication strategies unambiguously pave the way for our comprehensive understanding of viral pathogenesis and disease outcome, as well as for developing new antiviral strategies against plant virus disease. Recent studies of plant positive-strand RNA [(+)RNA] viruses have advanced our understanding of co-opted host factors and their roles in viral translation and replication. It is becoming clear that plant (+)RNA viruses harness host factors involved in membrane trafficking and lipid metabolism to establish the viral replication complex (VRC). In this review, we aim to discuss the contribution of co-opted host factors in translation and genome replication of plant (+)RNA viruses mainly focusing on those involved in the biogenesis of the VRC, which may act as a central hub in almost all the processes of viral infection as well as viral pathogenesis. PMID:26651023

  3. Identification of RNA Helicase A (RHA) as a New Host Factor in the Replication Cycle of FMDV

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foot-and-mouth disease virus (FMDV) as with other RNA viruses, recruits various host cell factors to assist in the translation and replication of the virus genome. In this study we investigated the role of RNA helicase A (RHA) in the life cycle of FMDV. Immunofluorescent microscopy combined with b...

  4. Biotic mortality factors affecting emerald ash borer (Agrilus planipennis) are highly dependent on life stage and host tree crown condition.

    PubMed

    Jennings, D E; Duan, J J; Shrewsbury, P M

    2015-10-01

    Emerald ash borer (EAB), Agrilus planipennis, is a serious invasive forest pest in North America responsible for killing tens to hundreds of millions of ash trees since it was accidentally introduced in the 1990 s. Although host-plant resistance and natural enemies are known to be important sources of mortality for EAB in Asia, less is known about the importance of different sources of mortality at recently colonized sites in the invaded range of EAB, and how these relate to host tree crown condition. To further our understanding of EAB population dynamics, we used a large-scale field experiment and life-table analyses to quantify the fates of EAB larvae and the relative importance of different biotic mortality factors at 12 recently colonized sites in Maryland. We found that the fates of larvae were highly dependent on EAB life stage and host tree crown condition. In relatively healthy trees (i.e., with a low EAB infestation) and for early instars, host tree resistance was the most important mortality factor. Conversely, in more unhealthy trees (i.e., with a moderate to high EAB infestation) and for later instars, parasitism and predation were the major sources of mortality. Life-table analyses also indicated how the lack of sufficient levels of host tree resistance and natural enemies contribute to rapid population growth of EAB at recently colonized sites. Our findings provide further evidence of the mechanisms by which EAB has been able to successfully establish and spread in North America. PMID:26072908

  5. Genome-wide association study identifies vitamin B5 biosynthesis as a host specificity factor in Campylobacter.

    PubMed

    Sheppard, Samuel K; Didelot, Xavier; Meric, Guillaume; Torralbo, Alicia; Jolley, Keith A; Kelly, David J; Bentley, Stephen D; Maiden, Martin C J; Parkhill, Julian; Falush, Daniel

    2013-07-16

    Genome-wide association studies have the potential to identify causal genetic factors underlying important phenotypes but have rarely been performed in bacteria. We present an association mapping method that takes into account the clonal population structure of bacteria and is applicable to both core and accessory genome variation. Campylobacter is a common cause of human gastroenteritis as a consequence of its proliferation in multiple farm animal species and its transmission via contaminated meat and poultry. We applied our association mapping method to identify the factors responsible for adaptation to cattle and chickens among 192 Campylobacter isolates from these and other host sources. Phylogenetic analysis implied frequent host switching but also showed that some lineages were strongly associated with particular hosts. A seven-gene region with a host association signal was found. Genes in this region were almost universally present in cattle but were frequently absent in isolates from chickens and wild birds. Three of the seven genes encoded vitamin B5 biosynthesis. We found that isolates from cattle were better able to grow in vitamin B5-depleted media and propose that this difference may be an adaptation to host diet. PMID:23818615

  6. New insights on the viral and host factors contributing to the airway pathogenesis caused by the respiratory syncytial virus.

    PubMed

    Lay, Margarita K; Bueno, Susan M; Gálvez, Nicolás; Riedel, Claudia A; Kalergis, Alexis M

    2016-09-01

    The respiratory syncytial virus (RSV) is the most prevalent etiological agent of lower respiratory tract infections and the first cause of hospitalization in infants due to respiratory disease worldwide. However, efforts to develop safe and effective vaccines and antivirals have been challenged by an incomplete understanding of the RSV pathogenesis and the host immune response to RSV infection in the airways. Here, we discuss recent advances in understanding the interaction between RSV and the epithelium to induce pathogenesis in the airways, such as the role of the RSV NS2 protein in the airway epithelium, as well as the events involved in the RSV entry process. In addition, we summarize the cellular factors produced by airway epithelial cells (AECs) in response to RSV infection that lead to the activation of innate and adaptive immune responses, inducing lung inflammation and disease. Further, we discuss the possible contribution of a recently identified cytokine, thymic stromal lymphopoitein (TSLP), in the lung immunopathology caused by RSV. PMID:26119025

  7. Regulation of the ndh gene of Escherichia coli by integration host factor and a novel regulator, Arr.

    PubMed

    Green, J; Anjum, M F; Guest, J R

    1997-09-01

    The ndh gene of Escherichia coli encodes the non-proton-translocating NADH dehydrogenase II. Expression of the ndh gene is subject to a complex network of regulatory controls at the transcriptional level. Under anaerobic conditions ndh is repressed by the regulator of fumarate and nitrate reduction (FNR). However, in the absence of FNR, ndh expression is activated by the amino acid response regulator (Arr) during anaerobic growth in rich medium. Expression of the ndh gene varies during the growth cycle in response to the intracellular concentration of the heat-stable DNA-binding protein, Fis. In this work two additional heat-stable proteins, integration host factor (IHF) and the histone-like protein HU were found to interact with the ndh promoter. IHF was shown to bind at three sites centred at +26, -17 and -58 in the ndh promoter (Kd = 10(-8) M), to prevent open-complex formation and to repress ndh transcription in vitro. Studies with an ndh-lacZ fusion confirmed that IHF represses ndh expression in vivo. Two putative binding sites for Arr, which overlap the two FNR boxes in the ndh promoter, were identified. Studies with the FNR-activated and amino-acid-inducible asparaginase II gene (ansB) showed that IHF and a component of the Arr-containing fraction (but not HU) interact with the corresponding ansB promoter. PMID:9308170

  8. Interaction of the human cytomegalovirus particle with the host cell induces hypoxia-inducible factor 1 alpha

    SciTech Connect

    McFarlane, Steven; Nicholl, Mary Jane; Sutherland, Jane S.; Preston, Chris M.

    2011-05-25

    The cellular protein hypoxia-inducible factor 1 alpha (HIF-1{alpha}) was induced after infection of human fibroblasts with human cytomegalovirus (HCMV). HCMV irradiated with ultraviolet light (uv-HCMV) also elicited the effect, demonstrating that the response was provoked by interaction of the infecting virion with the cell and that viral gene expression was not required. Although induction of HIF-1{alpha} was initiated by an early event, accumulation of the protein was not detected until 9 hours post infection, with levels increasing thereafter. Infection with uv-HCMV resulted in increased abundance of HIF-1{alpha}-specific RNA, indicating stimulation of transcription. In addition, greater phosphorylation of the protein kinase Akt was observed, and the activity of this enzyme was required for induction of HIF-1{alpha} to occur. HIF-1{alpha} controls the expression of many cellular gene products; therefore the findings reveal new ways in which interaction of the HCMV particle with the host cell may cause significant alterations to cellular physiology.

  9. Regulatory network analysis of transcription factors, microRNAs, target genes and host genes in human multiple myeloma.

    PubMed

    Huang, Zhuoyan; Xu, Zhiwen; Kunhao Wang, Kunhao Wang; Wang, Ning; Wang, Shang

    2015-11-01

    In recent years, molecular biologists have achieved great advance in micro RNA (miRNA) and gene investigation about the pathogenesis of multiple myeloma (MM). Existing research data of the transcription factors (TFs) and miRNAs is disperse and unorganized, which prevents researchers from investigating the mechanism and analyze regulatory pathways of MM systematically. In our research, regulatory interactions among miRNAs, TFs, host genes and target genes were imported to construct regulatory networks at three levels, including the abnormally expressed network and the related network as well as the global network. The abnormally expressed network was primary investigated cause it was an experimentally validated topological network, and it systematically explained the regulatory mechanism of MM. Its outstanding significance lies in that if we correct each abnormally expressed gene and miRNA to normal expression level by transcriptional control adjustment, thus the whole genetic expression network will return to normal state, and MM may not relapse. Additionally, analyses and comparisons to upstream as well as downstream of abnormally expressed miRNAs and genes in three networks highlighted some important regulators and key signaling pathways. For example, STAT3 and hsa-miR-125b, PIAS3 and hsa-miR-21 respectively formed self adaptation feedback regulations. The current research proposed a novel perspective to systematically explained the regulatory mechanism of MM and may contribute to further research and therapy of carcinomas. PMID:26687742

  10. Host-defense and trefoil factor family peptides in skin secretions of the Mawa clawed frog Xenopus boumbaensis (Pipidae).

    PubMed

    Conlon, J Michael; Mechkarska, Milena; Kolodziejek, Jolanta; Leprince, Jérôme; Coquet, Laurent; Jouenne, Thierry; Vaudry, Hubert; Nowotny, Norbert; King, Jay D

    2015-10-01

    Peptidomic analysis of norepinephrine-stimulated skin secretions from the octoploid Mawa clawed frog Xenopus boumbaensis Loumont, 1983 led to the identification and characterization of 15 host-defense peptides belonging to the magainin (two peptides), peptide glycine-leucine-amide (PGLa; three peptides), xenopsin precursor fragment (XPF; three peptides), caerulein precursor fragment (CPF; two peptides), and caerulein precursor fragment-related peptide (CPF-RP; five peptides) families. In addition, caerulein and three peptides with structural similarity to the trefoil factor family (TFF) peptides, xP2 and xP4 from Xenopus laevis were also present in the secretions. Consistent with data from comparisons of the nucleotides sequence of mitochondrial and nuclear genes, the primary structures of the peptides suggest a close phylogenetic relationship between X. boumbaensis and the octoploid frogs Xenopus amieti and Xenopus andrei. As the three species occupy disjunct ranges within Cameroon, it is suggested that they diverged from a common ancestor by allopatric speciation. PMID:25849343

  11. Intrinsic host restriction factors of human cytomegalovirus replication and mechanisms of viral escape.

    PubMed

    Landolfo, Santo; De Andrea, Marco; Dell'Oste, Valentina; Gugliesi, Francesca

    2016-08-12

    Before a pathogen even enters a cell, intrinsic immune defenses are active. This first-line defense is mediated by a variety of constitutively expressed cell proteins collectively termed "restriction factors" (RFs), and they form a vital element of the immune response to virus infections. Over time, however, viruses have evolved in a variety ways so that they are able to overcome these RF defenses via mechanisms that are specific for each virus. This review provides a summary of the universal characteristics of RFs, and goes on to focus on the strategies employed by some of the most important RFs in their attempt to control human cytomegalovirus (HCMV) infection. This is followed by a discussion of the counter-restriction mechanisms evolved by viruses to circumvent the host cell's intrinsic immune defenses. RFs include nuclear proteins IFN-γ inducible protein 16 (IFI16) (a Pyrin/HIN domain protein), Sp100, promyelocytic leukemia, and hDaxx; the latter three being the keys elements of nuclear domain 10 (ND10). IFI16 inhibits the synthesis of virus DNA by down-regulating UL54 transcription - a gene encoding a CMV DNA polymerase; in response, the virus antagonizes IFI16 via a process involving viral proteins UL97 and pp65 (pUL83), which results in the mislocalizing of IFI16 into the cytoplasm. In contrast, viral regulatory proteins, including pp71 and IE1, seek to modify or disrupt the ND10 proteins and thus block or reverse their inhibitory effects upon virus replication. All in all, detailed knowledge of these HCMV counter-restriction mechanisms will be fundamental for the future development of new strategies for combating HCMV infection and for identifying novel therapeutic agents. PMID:27563536

  12. Identification of TRAPPC8 as a Host Factor Required for Human Papillomavirus Cell Entry

    PubMed Central

    Ishii, Yoshiyuki; Nakahara, Tomomi; Kataoka, Michiyo; Kusumoto-Matsuo, Rika; Mori, Seiichiro; Takeuchi, Takamasa; Kukimoto, Iwao

    2013-01-01

    Human papillomavirus (HPV) is a non-enveloped virus composed of a circular DNA genome and two capsid proteins, L1 and L2. Multiple interactions between its capsid proteins and host cellular proteins are required for infectious HPV entry, including cell attachment and internalization, intracellular trafficking and viral genome transfer into the nucleus. Using two variants of HPV type 51, the Ma and Nu strains, we have previously reported that MaL2 is required for efficient pseudovirus (PsV) transduction. However, the cellular factors that confer this L2 dependency have not yet been identified. Here we report that the transport protein particle complex subunit 8 (TRAPPC8) specifically interacts with MaL2. TRAPPC8 knockdown in HeLa cells yielded reduced levels of reporter gene expression when inoculated with HPV51Ma, HPV16, and HPV31 PsVs. TRAPPC8 knockdown in HaCaT cells also showed reduced susceptibility to infection with authentic HPV31 virions, indicating that TRAPPC8 plays a crucial role in native HPV infection. Immunofluorescence microscopy revealed that the central region of TRAPPC8 was exposed on the cell surface and colocalized with inoculated PsVs. The entry of Ma, Nu, and L2-lacking PsVs into cells was equally impaired in TRAPPC8 knockdown HeLa cells, suggesting that TRAPPC8-dependent endocytosis plays an important role in HPV entry that is independent of L2 interaction. Finally, expression of GFP-fused L2 that can also interact with TRAPPC8 induced dispersal of the Golgi stack structure in HeLa cells, a phenotype also observed by TRAPPC8 knockdown. These results suggest that during viral intracellular trafficking, binding of L2 to TRAPPC8 inhibits its function resulting in Golgi destabilization, a process that may assist HPV genome escape from the trans-Golgi network. PMID:24244674

  13. Effect of stiffness and thickness ratio of host plate and piezoelectric patches on reduction of the stress concentration factor

    NASA Astrophysics Data System (ADS)

    Fesharaki, Javad Jafari; Madani, Seyed Ghasem; Golabi, Sa'id

    2016-06-01

    This paper focuses on the effects of stiffness ratio and thickness ratio on reducing stress concentration factor using piezoelectric patches in a rectangular plate with a hole, as a classical shape. Various locations of actuators and induction of positive/negative strains into the host plate are investigated and the best location of patches is presented. The study investigated the ratio effects and piezoelectric patches bounded on a rectangular host plate having various thicknesses and materials. Results show that the best position of actuators varies based on values of thickness and stiffness ratios of the host plate and piezoelectric patches. Also, the location of maximum stress concentration is transmitted from top and bottom of the hole to another point around the edge by changing the location of the piezoelectric actuators. To verify the results, some experimental tests are applied. The results show good agreement between the finite element analysis and experimental tests.

  14. Identification of RNA Binding Proteins Associated with Dengue Virus RNA in Infected Cells Reveals Temporally Distinct Host Factor Requirements

    PubMed Central

    Viktorovskaya, Olga V.; Greco, Todd M.; Cristea, Ileana M.; Thompson, Sunnie R.

    2016-01-01

    Background There are currently no vaccines or antivirals available for dengue virus infection, which can cause dengue hemorrhagic fever and death. A better understanding of the host pathogen interaction is required to develop effective therapies to treat DENV. In particular, very little is known about how cellular RNA binding proteins interact with viral RNAs. RNAs within cells are not naked; rather they are coated with proteins that affect localization, stability, translation and (for viruses) replication. Methodology/Principal Findings Seventy-nine novel RNA binding proteins for dengue virus (DENV) were identified by cross-linking proteins to dengue viral RNA during a live infection in human cells. These cellular proteins were specific and distinct from those previously identified for poliovirus, suggesting a specialized role for these factors in DENV amplification. Knockdown of these proteins demonstrated their function as viral host factors, with evidence for some factors acting early, while others late in infection. Their requirement by DENV for efficient amplification is likely specific, since protein knockdown did not impair the cell fitness for viral amplification of an unrelated virus. The protein abundances of these host factors were not significantly altered during DENV infection, suggesting their interaction with DENV RNA was due to specific recruitment mechanisms. However, at the global proteome level, DENV altered the abundances of proteins in particular classes, including transporter proteins, which were down regulated, and proteins in the ubiquitin proteasome pathway, which were up regulated. Conclusions/Significance The method for identification of host factors described here is robust and broadly applicable to all RNA viruses, providing an avenue to determine the conserved or distinct mechanisms through which diverse viruses manage the viral RNA within cells. This study significantly increases the number of cellular factors known to interact with

  15. Microscopy-based Assays for High-throughput Screening of Host Factors Involved in Brucella Infection of Hela Cells.

    PubMed

    Casanova, Alain; Low, Shyan H; Emmenlauer, Mario; Conde-Alvarez, Raquel; Salcedo, Suzana P; Gorvel, Jean-Pierre; Dehio, Christoph

    2016-01-01

    Brucella species are facultative intracellular pathogens that infect animals as their natural hosts. Transmission to humans is most commonly caused by direct contact with infected animals or by ingestion of contaminated food and can lead to severe chronic infections. Brucella can invade professional and non-professional phagocytic cells and replicates within endoplasmic reticulum (ER)-derived vacuoles. The host factors required for Brucella entry into host cells, avoidance of lysosomal degradation, and replication in the ER-like compartment remain largely unknown. Here we describe two assays to identify host factors involved in Brucella entry and replication in HeLa cells. The protocols describe the use of RNA interference, while alternative screening methods could be applied. The assays are based on the detection of fluorescently labeled bacteria in fluorescently labeled host cells using automated wide-field microscopy. The fluorescent images are analyzed using a standardized image analysis pipeline in CellProfiler which allows single cell-based infection scoring. In the endpoint assay, intracellular replication is measured two days after infection. This allows bacteria to traffic to their replicative niche where proliferation is initiated around 12 hr after bacterial entry. Brucella which have successfully established an intracellular niche will thus have strongly proliferated inside host cells. Since intracellular bacteria will greatly outnumber individual extracellular or intracellular non-replicative bacteria, a strain constitutively expressing GFP can be used. The strong GFP signal is then used to identify infected cells. In contrast, for the entry assay it is essential to differentiate between intracellular and extracellular bacteria. Here, a strain encoding for a tetracycline-inducible GFP is used. Induction of GFP with simultaneous inactivation of extracellular bacteria by gentamicin enables the differentiation between intracellular and extracellular

  16. Improved Growth Factor Directed Vascularization into Fibrin Constructs Through Inclusion of Additional Extracellular Molecules

    PubMed Central

    Smith, JD; Melhem, ME; Magge, KT; Waggoner, AS; Campbell, PG

    2009-01-01

    Using the chick chorioallantoic membrane assay (CAM) and a novel histological technique we investigated the ability of blood vessels to directly invade fibrin-based scaffolds. In our initial experiments utilizing vascular endothelial growth factor (VEGF165) we found no direct invasion. Instead, the fibrin was completely degraded and replaced with highly vascularized new tissue. Addition of fibroblast growth factor-2 (FGF-2), bone morphogenic protein-2 (BMP-2), or platelet-derived growth factor-BB (PDGF-BB) to the fibrin construct also did not result in construct vascularization. Because natural and regenerating tissues exhibit complex extracellular matrices (ECMs), we hypothesized that a more complex scaffold may improve blood vessel invasion. Addition of fibronectin, hyaluronic acid, and collagen type I within 20 mg/mL fibrin constructs resulted in no significant improvement. However, the same additive concentrations within 10 mg/mL fibrin constructs resulted in dramatic improvements, specifically with hyaluronic acid. Overall, we believe these results indicate the importance of structural and functional cues of not only in the initial scaffold but also as the construct is degraded and remodeled. Furthermore, the CAM assay may represent a useful model for understanding ECM interactions as well as for screening and designing tissue engineered scaffolds. PMID:17223139

  17. Pre-treatment factors associated with detecting additional brain metastases at stereotactic radiosurgery.

    PubMed

    Wardak, Zabi; Augustyn, Alexander; Zhu, Hong; Mickey, Bruce E; Whitworth, Louis A; Madden, Christopher J; Barnett, Samuel L; Abdulrahman, Ramzi E; Nedzi, Lucien A; Timmerman, Robert D; Choe, Kevin S

    2016-06-01

    The number of brain metastases identified on diagnostic magnetic resonance imaging (MRI) is a key factor in consideration of stereotactic radiosurgery (SRS). However, additional lesions are often detected on high-resolution SRS-planning MRI. We investigated pre-treatment clinical characteristics that are associated with finding additional metastases at SRS. Patients treated with SRS for brain metastases between the years of 2009-2014 comprised the study cohort. All patients underwent frame-fixed, 1 mm thick MRI on the day of SRS. Patient, tumor, and treatment characteristics were analyzed for an association with increase in number of metastases identified on SRS-planning MRI. 289 consecutive SRS cases were analyzed. 725 metastases were identified on pre-treatment MRI and 1062 metastases were identified on SRS-planning MRI. An increase in the number of metastases occurred in 34 % of the cases. On univariate analysis, more than four metastases and the diameter of the largest lesion were significantly associated with an increase in number of metastases on SRS-planning MRI. When stratified by the diameter of the largest lesion into <2, 2-3, or ≥3 cm, additional metastases were identified in 37, 29, and 18 %, respectively. While this increase in the number of metastases is largely due to the difference in imaging technique, the number and size of the metastases were also associated with finding additional lesions. These clinical factors may be considered when determining treatment options for brain metastases. PMID:26966096

  18. To be or not to be: The host genetic factor and beyond in Helicobacter pylori mediated gastro-duodenal diseases

    PubMed Central

    Datta De, Dipanjana; Roychoudhury, Susanta

    2015-01-01

    Helicobacter pylori (H. pylori) have long been associated with a spectrum of disease outcomes in the gastro-duodenal system. Heterogeneity in bacterial virulence factors or strains is not enough to explain the divergent disease phenotypes manifested by the infection. This review focuses on host genetic factors that are involved during infection and eventually are thought to influence the disease phenotype. We have summarized the different host genes that have been investigated for association studies in H. pylori mediated duodenal ulcer or gastric cancer. We discuss that as the bacteria co-evolved with the host; these host gene also show much variation across different ethnic population. We illustrate the allelic distribution of interleukin-1B, across different population which is one of the most popular candidate gene studied with respect to H. pylori infections. Further, we highlight that several polymorphisms in the pathway gene can by itself or collectively affect the acid secretion pathway axis (gastrin: somatostatin) thereby resulting in a spectrum of disease phenotype PMID:25780285

  19. Host Genetic Factors Affect Susceptibility to Norovirus Infections in Burkina Faso

    PubMed Central

    Nordgren, Johan; Nitiema, Léon W.; Ouermi, Djeneba; Simpore, Jacques; Svensson, Lennart

    2013-01-01

    Norovirus (NoV) constitutes the second most common viral pathogen causing pediatric diarrhea after rotavirus. In Africa, diarrhea is a major health problem in children, and yet few studies have been performed regarding NoV. The association of histo-blood group antigens (HBGA) and susceptibility to NoV infection is well established in Caucasian populations with non-secretors being resistant to many common NoV strains. No study regarding HBGA and NoV susceptibility has yet been performed in Africa. We collected 309 stool and 208 saliva samples from diarrheal children in Ouagadougou, Burkina Faso; May 2009 to March 2010. NoV was detected using real-time PCR, and genotyped by sequencing. Saliva samples were ABO, Lewis and secretor phenotyped using in house ELISA assays. NoV was detected in 12% (n = 37) of the samples. The genotype diversity was unusually large; overall the 37 positive samples belonged to 14 genotypes. Only children <2 years of age were NoV positive and the GII.4 NoVs were more frequent in the late dry season (Jan-May). NoV infections were observed less in children with the secretor-negative phenotype or blood group A (OR 0.18; p = 0.012 and OR 0.31; p = 0.054; respectively), with two non-secretors infected with genotypes GII.7 and GII.4 respectively. Lewis-negative (Lea−b−) children, representing 32% of the study population, were susceptible to GII, but were not infected with any NoV GI. GII.4 strains preferentially infected children with blood group B whereas secretor-positive children with blood group O were infected with the largest variety of genotypes. This is the first study identifying host genetic factors associated with susceptibility to NoV in an African population, and suggests that while the non-secretor phenotype provides protection; the Lewis b antigen is not necessary for GII infection. PMID:23894502

  20. Influence of temperature on symptom expression, detection of host factors in virus infected Piper nigrum L.

    PubMed

    Umadevi, P; Bhat, A I; Krishnamurthy, K S; Anandaraj, M

    2016-05-01

    Expression of symptoms in black pepper plants (Piper nigrum) infected with Piper yellow mottle virus (PYMoV) vary depending on the season, being high during summer months. Here, we explored the influence of temperature on symptom expression in PYMoV infected P. nigrum. Our controlled environment study revealed increase in virus titer, total proteins, IAA and reducing sugars when exposed to temperature stress. There was change in the 2-D separated protein before and after exposure. The 2-D proteomics LC-MS identified host and viral proteins suggesting virus-host interaction during symptom expression. The analysis as well as detection of host biochemical compounds may help in understanding the detailed mechanisms underlying the viral replication and damage to the crop, and thereby plan management strategies. PMID:27319055

  1. Synergistic and additive killing by antimicrobial factors found in human airway surface liquid.

    PubMed

    Singh, P K; Tack, B F; McCray, P B; Welsh, M J

    2000-11-01

    Airway surface liquid contains multiple factors thought to provide a first line of defense against bacteria deposited in the airways. Although the antimicrobial action of individual factors has been studied, less is known about how they work in combination. We examined the combined action of six antimicrobial peptides found in airway surface liquid. The paired combinations of lysozyme-lactoferrin, lysozyme-secretory leukocyte protease inhibitor (SLPI), and lactoferrin-SLPI were synergistic. The triple combination of lysozyme, lactoferrin, and SLPI showed even greater synergy. Other combinations involving the human beta-defensins, LL-37, and tobramycin (often administered to cystic fibrosis patients by inhalation) were additive. Because the airway surface liquid salt concentration may be elevated in cystic fibrosis patients, we examined the effect of salt on the synergistic combinations. As the ionic strength increased, synergistic interactions were lost. Our data suggest that the antibacterial potency of airway surface liquid may be significantly increased by synergistic and additive interactions between antimicrobial factors. These results also suggest that increased salt concentrations that may exist in cystic fibrosis could inhibit airway defenses by diminishing these synergistic interactions. PMID:11053013

  2. Genetic Structure in the Seabuckthorn Carpenter Moth (Holcocerus hippophaecolus) in China: The Role of Outbreak Events, Geographical and Host Factors

    PubMed Central

    Tao, Jing; Chen, Min; Zong, Shi-Xiang; Luo, You-Qing

    2012-01-01

    Understanding factors responsible for structuring genetic diversity is of fundamental importance in evolutionary biology. The seabuckthorn carpenter moth (Holcocerus hippophaecolus Hua) is a native species throughout the north of China and is considered the main threat to seabuckthorn, Hippophae rhamnoides L. We assessed the influence of outbreaks, environmental factors and host species in shaping the genetic variation and structure of H. hippophaecolus by using Amplified Fragment Length Polymorphism (AFLP) markers. We rejected the hypothesis that outbreak-associated genetic divergence exist, as evidenced by genetic clusters containing a combination of populations from historical outbreak areas, as well as non-outbreak areas. Although a small number of markers (4 of 933 loci) were identified as candidates under selection in response to population densities. H. hippophaecolus also did not follow an isolation-by-distance pattern. We rejected the hypothesis that outbreak and drought events were driving the genetic structure of H. hippophaecolus. Rather, the genetic structure appears to be influenced by various confounding bio-geographical factors. There were detectable genetic differences between H. hippophaecolus occupying different host trees from within the same geographic location. Host-associated genetic divergence should be confirmed by further investigation. PMID:22291983

  3. Identification of a Transcription Factor That Regulates Host Cell Exit and Virulence of Mycobacterium tuberculosis

    PubMed Central

    Srinivasan, Lalitha; Gurses, Serdar A.; Hurley, Benjamin E.; Miller, Jessica L.; Karakousis, Petros C.; Briken, Volker

    2016-01-01

    The interaction of Mycobacterium tuberculosis (Mtb) with host cell death signaling pathways is characterized by an initial anti-apoptotic phase followed by a pro-necrotic phase to allow for host cell exit of the bacteria. The bacterial modulators regulating necrosis induction are poorly understood. Here we describe the identification of a transcriptional repressor, Rv3167c responsible for regulating the escape of Mtb from the phagosome. Increased cytosolic localization of MtbΔRv3167c was accompanied by elevated levels of mitochondrial reactive oxygen species and reduced activation of the protein kinase Akt, and these events were critical for the induction of host cell necrosis and macroautophagy. The increase in necrosis led to an increase in bacterial virulence as reflected in higher bacterial burden and reduced survival of mice infected with MtbΔRv3167c. The regulon of Rv3167c thus contains the bacterial mediators involved in escape from the phagosome and host cell necrosis induction, both of which are crucial steps in the intracellular lifecycle and virulence of Mtb. PMID:27191591

  4. Host Factors Modulating RSV Infection: Use of Small Interfering RNAs to Probe Functional Importance.

    PubMed

    Caly, Leon; Li, Hong-Mei; Jans, David

    2016-01-01

    Although respiratory syncytial virus (RSV) is the leading cause of bronchiolitis and pneumonia in infants and the elderly worldwide [1], the protein-protein interactions between the host cell and virus remain poorly understood. We have used a focused small interfering RNA (siRNA) approach to knock-down and examine the role(s) of various host cell proteins. Here, we describe approaches for casein kinase 2α (CK2α) as a key example. We show how to study the effect of host gene (CK2α) knockdown using siRNA on cell-associated and released virus titers, using both quantitative RT-PCR, which measures the level of viral RNA, and plaque assay, which measures infectious virus directly. Both assays identified reduced viral titers with CK2α gene knock-down, indicating that it is likely required for efficient viral assembly and/or release. Effects were confirmed in RSV infected cells using the specific CK2α inhibitor 4,5,6,7-tetrabromobenzotriazole, revealing a similar reduction in viral titers as CK2α specific siRNA. This demonstrates that siRNA can be used to characterize critical host cell-RSV protein-protein interactions, and establishes CK2α as a future druggable target. PMID:27464690

  5. A Procedure for Estimating Enrollment and Cost Factors at Potential AFROTC Host-Sites.

    ERIC Educational Resources Information Center

    Alley, William E.; Berberich, George L.

    The development of effectiveness criteria for AFROTC detachments, and relationships between the criteria and various environmental and program characteristics are described. The objective of the study is the development of a method for estimating student enrollments and total operating costs at perspective host-site institutions by using…

  6. A host basal transcription factor is a key component for infection of rice by TALE-carrying bacteria

    PubMed Central

    Yuan, Meng; Ke, Yinggen; Huang, Renyan; Ma, Ling; Yang, Zeyu; Chu, Zhaohui; Xiao, Jinghua; Li, Xianghua; Wang, Shiping

    2016-01-01

    Transcription activator-like effectors (TALEs) are sequence-specific DNA binding proteins found in a range of plant pathogenic bacteria, where they play important roles in host-pathogen interactions. However, it has been unclear how TALEs, after they have been injected into the host cells, activate transcription of host genes required for infection success. Here, we show that the basal transcription factor IIA gamma subunit TFIIAγ5 from rice is a key component for infection by the TALE-carrying bacterium Xanthomonas oryzae pv. oryzae, the causal agent for bacterial blight. Direct interaction of several TALEs with TFIIAγ5 is required for activation of disease susceptibility genes. Conversely, reduced expression of the TFIIAγ5 host gene limits the induction of susceptibility genes and thus decreases bacterial blight symptoms. Suppression or mutation of TFIIAγ5 can also reduce bacterial streak, another devastating disease of rice caused by TALE-carrying X. oryzae pv. oryzicola. These results have important implications for formulating a widely applicable strategy with which to improve resistance of plants to TALE-carrying pathogens. DOI: http://dx.doi.org/10.7554/eLife.19605.001 PMID:27472897

  7. A host basal transcription factor is a key component for infection of rice by TALE-carrying bacteria.

    PubMed

    Yuan, Meng; Ke, Yinggen; Huang, Renyan; Ma, Ling; Yang, Zeyu; Chu, Zhaohui; Xiao, Jinghua; Li, Xianghua; Wang, Shiping

    2016-01-01

    Transcription activator-like effectors (TALEs) are sequence-specific DNA binding proteins found in a range of plant pathogenic bacteria, where they play important roles in host-pathogen interactions. However, it has been unclear how TALEs, after they have been injected into the host cells, activate transcription of host genes required for infection success. Here, we show that the basal transcription factor IIA gamma subunit TFIIAγ5 from rice is a key component for infection by the TALE-carrying bacterium Xanthomonas oryzae pv. oryzae, the causal agent for bacterial blight. Direct interaction of several TALEs with TFIIAγ5 is required for activation of disease susceptibility genes. Conversely, reduced expression of the TFIIAγ5 host gene limits the induction of susceptibility genes and thus decreases bacterial blight symptoms. Suppression or mutation of TFIIAγ5 can also reduce bacterial streak, another devastating disease of rice caused by TALE-carrying X. oryzae pv. oryzicola. These results have important implications for formulating a widely applicable strategy with which to improve resistance of plants to TALE-carrying pathogens. PMID:27472897

  8. Gonococcal porin IB activates NF-kappaB in human urethral epithelium and increases the expression of host antiapoptotic factors.

    PubMed

    Binnicker, Matthew J; Williams, Richard D; Apicella, Michael A

    2004-11-01

    Infection of human urethral epithelial cells (UECs) with Neisseria gonorrhoeae increases the transcription of several host antiapoptotic genes, including bfl-1, cox-2, and c-IAP-2. In order to identify the bacterial factor(s) responsible for eliciting these changes, the transcriptional status of apoptotic machinery was monitored in UECs challenged with certain gonococcal membrane components. Initially, we observed that infection of UECs with gentamicin-killed gonococci increased the expression of the antiapoptotic Bcl-2 family member, bfl-1. This observation indicated that viable, replicating bacteria are not required for induction of antiapoptotic gene expression. Confirming this observation, treatment of UECs with purified gonococcal membrane increased the expression of bfl-1, cox-2, and c-IAP-2. This finding suggested that a factor or multiple factors present in the outer membrane (OM) are responsible for altering UEC antiapoptotic gene expression. Interestingly, treatment of UECs with gonococcal porin IB (PorB IB), a major constituent of the OM, significantly increased the transcription of bfl-1, cox-2, and c-IAP-2. The upregulation of these genes by PorB IB was determined to be dependent on NF-kappaB activation, as inhibiting NF-kappaB blocked induced expression of these genes. This work demonstrates the altered expression of host apoptotic factors in response to gonococcal PorB IB and supports a model whereby UEC cell death may be modulated as a potential mechanism of bacterial survival and proliferation. PMID:15501771

  9. Validation-based insertional mutagenesis for identification of Nup214 as a host factor for EV71 replication in RD cells

    SciTech Connect

    Wang, Bei; Zhang, XiaoYu; Zhao, Zhendong

    2013-08-02

    Highlights: •We introduced a new mutagenesis strategy named VBIM to the viral research. •This method can identify either host factors or host restriction factors. •Using VBIM system, we identified Nup214 as a host factor for EV71 replication in RD cells. -- Abstract: Lentiviral validation-based insertional mutagenesis (VBIM) is a sophisticated, forward genetic approach that is used for the investigation of signal transduction in mammalian cells. Using VBIM, we conducted function-based genetic screening for host genes that affect enterovirus 71 (EV71) viral replication. This included host factors that are required for the life cycle of EV71 and host restriction factors that inhibit EV71 replication. Several cell clones, resistant to EV71, were produced using EV71 infection as a selection pressure and the nuclear pore protein 214 (Nup214) was identified as a host factor required for EV71 replication. In SD2-2, the corresponding VBIM lentivirus transformed clone, the expression of endogenous Nup214 was significantly down-regulated by the reverse inserted VBIM promoter. After Cre recombinase-mediated excision of the VBIM promoter, the expression of Nup214 recovered and the clone regained sensitivity to the EV71 infection. Furthermore, over-expression of Nup214 in the cells suggested that Nup214 was promoting EV71 replication. Results of this study indicate that a successful mutagenesis strategy has been established for screening host genes related to viral replication.

  10. Interferon Regulatory Factor 6 Has a Protective Role in the Host Response to Endotoxic Shock

    PubMed Central

    Volk, Paige; Moreland, Jessica G.; Dunnwald, Martine

    2016-01-01

    Interferon Regulatory Factor (IRF) 6, a member of the IRF family, is essential for epidermal and orofacial embryonic development. Irf6 is strongly expressed in keratinocytes, in which it regulates epidermal proliferation, differentiation, and migration. A recent role for Irf6 in Toll-like receptor 2-dependent chemokine gene expression was also reported in an epithelial cell line. However, a function for Irf6 in innate immune cells was not previously reported. In the present study, we investigated the expression and function of Irf6 in bone marrow-derived neutrophils and macrophages. We show here, using a conditional knockout of Irf6 in lysosymeM expressing cells, that Irf6 is required for resistance to LPS-induced endotoxic shock. In addition, Irf6-deficient bone marrow-derived neutrophils exhibited increased chemotactic index and velocity compared with wild-type cells in vitro. TLR4-specific KC and IL6 secretions were upregulated in Irf6-deficient bone marrow-derived macrophages in vitro. These cells also exhibited an increased level of phosphorylated IkBa. Collectively, our findings suggest a role for Irf6 in the resistance to endotoxic shock due to NFk-B-mediated alteration of cytokine production. PMID:27035130

  11. Delineating the Requirement for the Borrelia burgdorferi Virulence Factor OspC in the Mammalian Host

    PubMed Central

    Stewart, Philip E.; Wang, Xiaohui; Bueschel, Dawn M.; Clifton, Dawn R.; Grimm, Dorothee; Tilly, Kit; Carroll, James A.; Weis, Janis J.; Rosa, Patricia A.

    2006-01-01

    We previously demonstrated that outer surface protein C (OspC) of Borrelia burgdorferi is essential for establishing mammalian infection. However, the role of OspC in mammalian infection is unknown. Here, we report experiments designed to distinguish between two models of OspC function in the mammalian host: (i) OspC fulfills an essential physiological role for growth and host adaptation or (ii) OspC provides a protective role for evasion of components of the innate immune response. We found that a B. burgdorferi ospC mutant, previously demonstrated to be noninfectious in both immunocompetent and SCID mice, could survive in the relatively immune-privileged environment of dialysis membrane chambers implanted within the peritoneum of a rat. The ospC mutant also adapts to the mammalian environment, as determined by the protein profiles of the chamber-cultivated spirochetes. Therefore, OspC does not appear to provide a physiological function for the survival of B. burgdorferi within the mammalian host. The second model, evasion of the innate immune system, was tested by assessing the infectivity of the ospC mutant in mice deficient for myeloid differentiation protein 88 (MyD88). Recent studies have shown that B. burgdorferi is prevented from reaching high cell numbers in the mammalian host by MyD88-dependent signaling pathways. The ospC mutant was incapable of infecting MyD88-deficient mice, suggesting that the role of OspC cannot be related solely to evasion of MyD88-mediated innate immunity. These results reiterate the importance of OspC in mammalian infection and eliminate simple models of function for this enigmatic protein. PMID:16714587

  12. Host range and properties of the Pseudomonas aeruginosa R factor R1822.

    PubMed

    Olsen, R H; Shipley, P

    1973-02-01

    R1822, a plasmid specifying multiple drug resistances, has been transferred to a variety of species representative of related and unrelated genera. The host range of the plasmid includes Enterobacteriaceae, soil saprophytes, Neisseria perflava, and photosynthetic bacteria. With the acquisition of drug resistance(s), these strains became sensitive to a small, ribonuclease-sensitive bacteriophage, designated PRR1, isolated by enrichment from sewage. PMID:4632321

  13. Factors affecting the anthelmintic efficacy of papaya latex in vivo: host sex and intensity of infection.

    PubMed

    Luoga, Wenceslaus; Mansur, Fadlul; Lowe, Ann; Duce, Ian R; Buttle, David J; Behnke, Jerzy M

    2015-07-01

    The development of plant-derived cysteine proteinases, such as those in papaya latex, as novel anthelmintics requires that the variables affecting efficacy be fully evaluated. Here, we conducted two experiments, the first to test for any effect of host sex and the second to determine whether the intensity of the worm burden carried by mice would influence efficacy. In both experiments, we used the standard C3H mouse reference strain in which papaya latex supernatant (PLS) consistently shows >80 % reduction in Heligmosomoides bakeri worm burdens, but to broaden the perspective, we also included for comparison mice of other strains that are known to respond more poorly to treatment with papaya latex. Our results confirmed that there is a strong genetic influence affecting efficacy of PLS in removing adult worm burdens. However, there was no effect of host sex on efficacy (C3H and NIH) and no effect of infection intensity (C3H and BALB/c). These results offer optimism that plant-derived cysteine proteinases (CPs), such as these from papaya latex, can function as effective anthelmintics, with neither host sex nor infection intensity presenting further hurdles to impede their development for future medicinal and veterinary usage. PMID:25855350

  14. Coordinated Destruction of Cellular Messages in Translation Complexes by the Gammaherpesvirus Host Shutoff Factor and the Mammalian Exonuclease Xrn1

    PubMed Central

    Kumar, G. Renuka; Wong, Wesley; Jackson, Andrew O.; Glaunsinger, Britt A.

    2011-01-01

    Several viruses encode factors that promote host mRNA degradation to silence gene expression. It is unclear, however, whether cellular mRNA turnover pathways are engaged to assist in this process. In Kaposi's sarcoma-associated herpesvirus this phenotype is enacted by the host shutoff factor SOX. Here we show that SOX-induced mRNA turnover is a two-step process, in which mRNAs are first cleaved internally by SOX itself then degraded by the cellular exonuclease Xrn1. SOX therefore bypasses the regulatory steps of deadenylation and decapping normally required for Xrn1 activation. SOX is likely recruited to translating mRNAs, as it cosediments with translation initiation complexes and depletes polysomes. Cleaved mRNA intermediates accumulate in the 40S fraction, indicating that recognition occurs at an early stage of translation. This is the first example of a viral protein commandeering cellular mRNA turnover pathways to destroy host mRNAs, and suggests that Xrn1 is poised to deplete messages undergoing translation in mammalian cells. PMID:22046136

  15. Three WRKY transcription factors additively repress abscisic acid and gibberellin signaling in aleurone cells.

    PubMed

    Zhang, Liyuan; Gu, Lingkun; Ringler, Patricia; Smith, Stanley; Rushton, Paul J; Shen, Qingxi J

    2015-07-01

    Members of the WRKY transcription factor superfamily are essential for the regulation of many plant pathways. Functional redundancy due to duplications of WRKY transcription factors, however, complicates genetic analysis by allowing single-mutant plants to maintain wild-type phenotypes. Our analyses indicate that three group I WRKY genes, OsWRKY24, -53, and -70, act in a partially redundant manner. All three showed characteristics of typical WRKY transcription factors: each localized to nuclei and yeast one-hybrid assays indicated that they all bind to W-boxes, including those present in their own promoters. Quantitative real time-PCR (qRT-PCR) analyses indicated that the expression levels of the three WRKY genes varied in the different tissues tested. Particle bombardment-mediated transient expression analyses indicated that all three genes repress the GA and ABA signaling in a dosage-dependent manner. Combination of all three WRKY genes showed additive antagonism of ABA and GA signaling. These results suggest that these WRKY proteins function as negative transcriptional regulators of GA and ABA signaling. However, different combinations of these WRKY genes can lead to varied strengths in suppression of their targets. PMID:26025535

  16. Effect of Addition of Chin Strap on PAP Compliance, Nightly Duration of Use, and Other Factors

    PubMed Central

    Knowles, Shelley R.; O'Brien, Daniel T.; Zhang, Shiling; Devara, Anupama; Rowley, James A.

    2014-01-01

    Study Objectives: A chinstrap is potentially useful to reduce unintentional air leak by preventing mouth opening during PAP treatment. This study examines whether the addition of a chinstrap to PAP therapy has any effect on adherence, nightly duration of use, air leak, and residual AHI. Methods: This was a retrospective study performed at an AASM-accredited VAMC sleep center. Clinical sleep data of veterans (n = 124) prescribed PAP therapy for sleep apnea was evaluated, and the effect of chinstrap use vs non-use on the above parameters was assessed. Results: Chinstrap users had significantly greater PAP adherence, longer nightly duration of PAP use, lower residual AHI and lower leak compared to chinstrap non-users at first follow up visit. Conclusions: The addition of a chin strap to PAP therapy is a simple and inexpensive method of increasing PAP adherence. Citation: Knowles SR; O'Brien DT; Zhang S; Devara A; Rowley JA. Effect of addition of chin strap on PAP compliance, nightly duration of use, and other factors. J Clin Sleep Med 2014;10(4):377-383. PMID:24733982

  17. KAP1 Is a Host Restriction Factor That Promotes Human Adenovirus E1B-55K SUMO Modification

    PubMed Central

    Bürck, Carolin; Mund, Andreas; Berscheminski, Julia; Kieweg, Lisa; Müncheberg, Sarah

    2015-01-01

    ABSTRACT Once transported to the replication sites, human adenoviruses (HAdVs) need to ensure decondensation and transcriptional activation of their viral genomes to synthesize viral proteins and initiate steps to reprogram the host cell for viral replication. These early stages during adenoviral infection are poorly characterized but represent a decisive moment in the establishment of a productive infection. Here, we identify a novel host viral restriction factor, KAP1. This heterochromatin-associated transcription factor regulates the dynamic organization of the host chromatin structure via its ability to influence epigenetic marks and chromatin compaction. In response to DNA damage, KAP1 is phosphorylated and functionally inactive, resulting in chromatin relaxation. We discovered that KAP1 posttranslational modification is dramatically altered during HAdV infection to limit the antiviral capacity of this host restriction factor, which represents an essential step required for efficient viral replication. Conversely, we also observed during infection an HAdV-mediated decrease of KAP1 SUMO moieties, known to promote chromatin decondensation events. Based on our findings, we provide evidence that HAdV induces KAP1 deSUMOylation to minimize epigenetic gene silencing and to promote SUMO modification of E1B-55K by a so far unknown mechanism. IMPORTANCE Here we describe a novel cellular restriction factor for human adenovirus (HAdV) that sheds light on very early modulation processes in viral infection. We reported that chromatin formation and cellular SWI/SNF chromatin remodeling play key roles in HAdV transcriptional regulation. We observed that the cellular chromatin-associated factor and epigenetic reader SPOC1 represses HAdV infection and gene expression. Here, we illustrate the role of the SPOC1-interacting factor KAP1 during productive HAdV growth. KAP1 binds to the viral E1B-55K protein, promoting its SUMO modification, therefore illustrating a crucial step for

  18. Knockdown of specific host factors protects against influenza virus-induced cell death

    PubMed Central

    Tran, A T; Rahim, M N; Ranadheera, C; Kroeker, A; Cortens, J P; Opanubi, K J; Wilkins, J A; Coombs, K M

    2013-01-01

    Cell death is a characteristic consequence of cellular infection by influenza virus. Mounting evidence indicates the critical involvement of host-mediated cellular death pathways in promoting efficient influenza virus replication. Furthermore, it appears that many signaling pathways, such as NF-κB, formerly suspected to solely promote cell survival, can also be manipulated to induce cell death. Current understanding of the cell death pathways involved in influenza virus-mediated cytopathology and in virus replication is limited. This study was designed to identify host genes that are required for influenza-induced cell death. The approach was to perform genome-wide lentiviral-mediated human gene silencing in A549 cells and determine which genes could be silenced to provide resistance to influenza-induced cell death. The assay proved to be highly reproducible with 138 genes being identified in independent screens. The results were independently validated using siRNA to each of these candidates. Graded protection was observed in this screen with the silencing of any of 19 genes, each providing >85% protection. Three gene products, TNFSF13 (APRIL), TNFSF12-TNFSF13 (TWE-PRIL) and USP47, were selected because of the high levels of protection conferred by their silencing. Protein and mRNA silencing and protection from influenza-induced cell death was confirmed using multiple shRNA clones and siRNA, indicating the specificity of the effects. USP47 knockdown prevented proper viral entry into the host cell, whereas TNFSF12-13/TNFSF13 knockdown blocked a late stage in viral replication. This screening approach offers the means to identify a large number of potential candidates for the analysis of viral-induced cell death. These results may also have much broader applicability in defining regulatory mechanisms involved in cell survival. PMID:23949218

  19. Factors which Limit the Value of Additional Redundancy in Human Rated Launch Vehicle Systems

    NASA Technical Reports Server (NTRS)

    Anderson, Joel M.; Stott, James E.; Ring, Robert W.; Hatfield, Spencer; Kaltz, Gregory M.

    2008-01-01

    The National Aeronautics and Space Administration (NASA) has embarked on an ambitious program to return humans to the moon and beyond. As NASA moves forward in the development and design of new launch vehicles for future space exploration, it must fully consider the implications that rule-based requirements of redundancy or fault tolerance have on system reliability/risk. These considerations include common cause failure, increased system complexity, combined serial and parallel configurations, and the impact of design features implemented to control premature activation. These factors and others must be considered in trade studies to support design decisions that balance safety, reliability, performance and system complexity to achieve a relatively simple, operable system that provides the safest and most reliable system within the specified performance requirements. This paper describes conditions under which additional functional redundancy can impede improved system reliability. Examples from current NASA programs including the Ares I Upper Stage will be shown.

  20. Steroids Versus Steroids Plus Additional Agent in Frontline Treatment of Acute Graft-versus-Host Disease: A Systematic Review and Meta-Analysis of Randomized Trials.

    PubMed

    Rashidi, Armin; DiPersio, John F; Sandmaier, Brenda M; Colditz, Graham A; Weisdorf, Daniel J

    2016-06-01

    Despite extensive research in the last few decades, progress in treatment of acute graft-versus-host disease (aGVHD), a common complication of allogeneic hematopoietic cell transplantation (HCT), has been limited and steroids continue to be the standard frontline treatment. Randomized clinical trials (RCTs) have failed to find a beneficial effect of escalating immunosuppression using additional agents. Considering the small number of RCTs, limited sample sizes, and frequent early termination because of anticipated futility, we conducted a systematic review and an aggregate data meta-analysis to explore whether a true efficacy signal has been missed because of the limitations of individual RCTs. Seven reports met our inclusion criteria. The control arm in all studies was 2 mg/kg/day prednisone (or equivalent). The additional agent(s) used in the experimental arm(s) were higher-dose steroids, antithymocyte globulin, infliximab, anti-interleukin-2 receptor antibody (daclizumab and BT563), CD5-specific immunotoxin, and mycophenolate mofetil. Random effects meta-analysis revealed no efficacy signal in pooled response rates at various times points. Overall survival at 100 days was significantly worse in the experimental arm (relative risk [RR], .83; 95% confidence interval [CI], .74 to .94; P = .004, data from 3 studies) and showed a similar trend (albeit not statistically significantly) at 1 year as well (RR, .86; 95% CI, .68 to 1.09; P = .21, data from 5 studies). In conclusion, these results argue against the value of augmented generic immunosuppression beyond steroids for frontline treatment of aGVHD and emphasize the importance of developing alternative strategies. Novel forms of immunomodulation and targeted therapies against non-immune-related pathways may enhance the efficacy of steroids in this setting, and early predictive and prognostic biomarkers can help identify the subgroup of patients who would likely need treatments other than (or in addition to

  1. Nuclear Localization of the C1 Factor (Host Cell Factor) in Sensory Neurons Correlates with Reactivation of Herpes Simplex Virus from Latency

    NASA Astrophysics Data System (ADS)

    Kristie, Thomas M.; Vogel, Jodi L.; Sears, Amy E.

    1999-02-01

    After a primary infection, herpes simplex virus is maintained in a latent state in neurons of sensory ganglia until complex stimuli reactivate viral lytic replication. Although the mechanisms governing reactivation from the latent state remain unknown, the regulated expression of the viral immediate early genes represents a critical point in this process. These genes are controlled by transcription enhancer complexes whose assembly requires and is coordinated by the cellular C1 factor (host cell factor). In contrast to other tissues, the C1 factor is not detected in the nuclei of sensory neurons. Experimental conditions that induce the reactivation of herpes simplex virus in mouse model systems result in rapid nuclear localization of the protein, indicating that the C1 factor is sequestered in these cells until reactivation signals induce a redistribution of the protein. The regulated localization suggests that C1 is a critical switch determinant of the viral lytic-latent cycle.

  2. A Host-Specific Factor is Necessary for Efficient Folding of the Autotransporter Plasmid-Encoded Toxin

    PubMed Central

    Nemec, Kathleen N.; Scaglione, Patricia; Navarro-García, Fernando; Huerta, Jazmín; Tatulian, Suren A.; Teter, Ken

    2010-01-01

    Autotransporters are the most common virulence factors secreted from Gram-negative pathogens. Until recently, autotransporter folding and outer membrane translocation were thought to be self-mediated events that did not require accessory factors. Here, we report that two variants of the autotransporter plasmid-encoded toxin are secreted by a lab strain of Escherichia coli. Biophysical analysis and cell-based toxicity assays demonstrated that only one of the two variants was in a folded, active conformation. The misfolded variant was not produced by a pathogenic strain of enteroaggregative E. coli and did not result from protein overproduction in the lab strain of E. coli. Our data suggest a host-specific factor is required for efficient folding of plasmid-encoded toxin. PMID:19944129

  3. Enhancement of antibody production by growth factor addition in perfusion and hollow-fiber culture systems.

    PubMed

    Omasa, T; Kobayashi, M; Nishikawa, T; Shioya, S; Suga, K; Uemura, S; Kitani, Y; Imamura, Y

    1995-12-20

    The effects of the high-molecular-weight growth factors, transferrin and bovine serum albumin (BSA), on antibody production were analyzed quantitatively in continuous hollow-fiber cultivation over a period of 60 days. Transferrin enhanced cell growth but had no significant effect on the specific antibody production rate, whereas BSA significantly enhanced antibody production. The antibody production rate was increased 4- and 14-fold respectively by feeding BSA at 2 and 5 g L(-1) into the EC side of the system (the side connected to the cell-containing outer part of the hollow-fiber unit) compared with the production achieved without BSA. Addition of 5 g L(1) BSA into the IC side of the system (the side connected to the inner part of the hollow-fiber unit) resulted in a 2.5-fold increase in the antibody production rate. The effect of BSA was also analyzed using the perfusion culture system with a separation unit. When fresh medium containing either 2 or 5 g L(-1) BSA was fed into the reactor, both the specific growth rate and specific death rate increased, while the specific antibody production rate was increased 2- and 25-fold, respectively, by feeding BSA at these two concentrations compared with no addition. Comparing the two systems, the increase in the antibody production rate achieved with the hollow-fiber system was threefold greater than that in the perfusion culture system with the same concentration of BSA feeding. (c) 1995 John Wiley & Sons, Inc. PMID:18623537

  4. Regulatory Variation in HIV-1 Dependency Factor ZNRD1 Associates with Host Resistance to HIV-1 Acquisition

    PubMed Central

    An, Ping; Goedert, James J.; Donfield, Sharyne; Buchbinder, Susan; Kirk, Gregory D.; Detels, Roger; Winkler, Cheryl A.

    2014-01-01

    Background. ZNRD1 was identified as a host protein required for the completion of the human immunodeficiency virus (HIV) lifecycle in a genome-wide screen using small interfering RNA gene silencing. Subsequently, a genome-wide association study (GWAS) of host determinants for HIV-1 disease identified an association of single nucleotide polymorphisms (SNPs) in the ZNRD1 region with CD4+ T-cell depletion. Methods. We investigated the effects of SNPs in the ZNRD1 region on human immunodeficiency virus type 1 (HIV-1) infection and progression to clinical outcomes in 5 US-based HIV-1 longitudinal cohorts consisting of men who have sex with men, males with hemophilia, and injection drug users (IDUs) (n = 1865). SNP function was evaluated by electrophoretic mobility shift assay and promoter luciferase assay. Results. A haplotype in the ZNRD1 gene showed significant association with a 35% decreased risk of HIV-1 acquisition (OR = 0.65, 95% CI, .47–.89), independent of HLA-C rs9264942, in European Americans. The SNP rs3132130 tagging this haplotype, located in the ZNRD1 5′ upstream region, caused a loss of nuclear factor binding and decrease in ZNRD1 promoter activity. ZNRD1 variants also affected HIV-1 disease progression in European- and African-American cohorts. Conclusions. This study provides novel evidence that ZNRD1 polymorphism may confer host resistance to HIV-1 acquisition. PMID:24842830

  5. Characterization of Citrus sinensis transcription factors closely associated with the non-host response to Xanthomonas campestris pv. vesicatoria.

    PubMed

    Daurelio, Lucas D; Romero, María S; Petrocelli, Silvana; Merelo, Paz; Cortadi, Adriana A; Talón, Manuel; Tadeo, Francisco R; Orellano, Elena G

    2013-07-01

    Plants, when exposed to certain pathogens, may display a form of genotype-independent resistance, known as non-host response. In this study, the response of Citrus sinensis (sweet orange) leaves to Xanthomonas campestris pv. vesicatoria (Xcv), a pepper and tomato pathogenic bacterium, was analyzed through biochemical assays and cDNA microarray hybridization and compared with Asiatic citrus canker infection caused by Xanthomonas citri subsp. citri. Citrus leaves exposed to the non-host bacterium Xcv showed hypersensitive response (HR) symptoms (cell death), a defense mechanism common in plants but poorly understood in citrus. The HR response was accompanied by differentially expressed genes that are associated with biotic stress and cell death. Moreover, 58 transcription factors (TFs) were differentially regulated by Xcv in citrus leaves, including 26 TFs from the stress-associated families AP2-EREBP, bZip, Myb and WRKY. Remarkably, in silico analysis of the distribution of expressed sequence tags revealed that 10 of the 58 TFs, belonging to C2C2-GATA, C2H2, CCAAT, HSF, NAC and WRKY gene families, were specifically over-represented in citrus stress cDNA libraries. This study identified candidate TF genes for the regulation of key steps during the citrus non-host HR. Furthermore, these TFs might be useful in future strategies of molecular breeding for citrus disease resistance. PMID:23453188

  6. The addition of sirolimus to the graft-versus-host disease prophylaxis regimen in reduced intensity allogeneic stem cell transplantation for lymphoma: a multicentre randomized trial.

    PubMed

    Armand, Philippe; Kim, Haesook T; Sainvil, Marie-Michele; Lange, Paulina B; Giardino, Angela A; Bachanova, Veronika; Devine, Steven M; Waller, Edmund K; Jagirdar, Neera; Herrera, Alex F; Cutler, Corey; Ho, Vincent T; Koreth, John; Alyea, Edwin P; McAfee, Steven L; Soiffer, Robert J; Chen, Yi-Bin; Antin, Joseph H

    2016-04-01

    Inhibition of the mechanistic target of rapamycin (mTOR) pathway has clinical activity in lymphoma. The mTOR inhibitor sirolimus has been used in the prevention and treatment of graft-versus-host disease (GVHD) after allogeneic haematopoietic stem cell transplantation (HSCT). A retrospective study suggested that patients with lymphoma undergoing reduced intensity conditioning (RIC) HSCT who received sirolimus as part of their GVHD prophylaxis regimen had a lower rate of relapse. We therefore performed a multicentre randomized trial comparing tacrolimus, sirolimus and methotrexate to standard regimens in adult patients undergoing RIC HSCT for lymphoma in order to assess the possible benefit of sirolimus on HSCT outcome. 139 patients were randomized. There was no difference overall in 2-year overall survival, progression-free survival, relapse, non-relapse mortality or chronic GVHD. However, the sirolimus-containing arm had a significantly lower incidence of grade II-IV acute GVHD (9% vs. 25%, P = 0·015), which was more marked for unrelated donor grafts. In conclusion, the addition of sirolimus for GVHD prophylaxis in RIC HSCT is associated with no increased overall toxicity and a lower risk of acute GVHD, although it does not improve survival; this regimen is an acceptable option for GVHD prevention in RIC HSCT. This trial is registered at clinicaltrials.gov (NCT00928018). PMID:26729448

  7. Dual RNA-Sequencing of Eucalyptus nitens during Phytophthora cinnamomi Challenge Reveals Pathogen and Host Factors Influencing Compatibility

    PubMed Central

    Meyer, Febé E.; Shuey, Louise S.; Naidoo, Sitha; Mamni, Thandekile; Berger, Dave K.; Myburg, Alexander A.; van den Berg, Noëlani; Naidoo, Sanushka

    2016-01-01

    Damage caused by Phytophthora cinnamomi Rands remains an important concern on forest tree species. The pathogen causes root and collar rot, stem cankers, and dieback of various economically important Eucalyptus spp. In South Africa, susceptible cold tolerant Eucalyptus plantations have been affected by various Phytophthora spp. with P. cinnamomi considered one of the most virulent. The molecular basis of this compatible interaction is poorly understood. In this study, susceptible Eucalyptus nitens plants were stem inoculated with P. cinnamomi and tissue was harvested five days post inoculation. Dual RNA-sequencing, a technique which allows the concurrent detection of both pathogen and host transcripts during infection, was performed. Approximately 1% of the reads mapped to the draft genome of P. cinnamomi while 78% of the reads mapped to the Eucalyptus grandis genome. The highest expressed P. cinnamomi gene in planta was a putative crinkler effector (CRN1). Phylogenetic analysis indicated the high similarity of this P. cinnamomi CRN1 to that of Phytophthora infestans. Some CRN effectors are known to target host nuclei to suppress defense. In the host, over 1400 genes were significantly differentially expressed in comparison to mock inoculated trees, including suites of pathogenesis related (PR) genes. In particular, a PR-9 peroxidase gene with a high similarity to a Carica papaya PR-9 ortholog previously shown to be suppressed upon infection by Phytophthora palmivora was down-regulated two-fold. This PR-9 gene may represent a cross-species effector target during P. cinnamomi infection. This study identified pathogenicity factors, potential manipulation targets, and attempted host defense mechanisms activated by E. nitens that contributed to the susceptible outcome of the interaction. PMID:26973660

  8. Dual RNA-Sequencing of Eucalyptus nitens during Phytophthora cinnamomi Challenge Reveals Pathogen and Host Factors Influencing Compatibility.

    PubMed

    Meyer, Febé E; Shuey, Louise S; Naidoo, Sitha; Mamni, Thandekile; Berger, Dave K; Myburg, Alexander A; van den Berg, Noëlani; Naidoo, Sanushka

    2016-01-01

    Damage caused by Phytophthora cinnamomi Rands remains an important concern on forest tree species. The pathogen causes root and collar rot, stem cankers, and dieback of various economically important Eucalyptus spp. In South Africa, susceptible cold tolerant Eucalyptus plantations have been affected by various Phytophthora spp. with P. cinnamomi considered one of the most virulent. The molecular basis of this compatible interaction is poorly understood. In this study, susceptible Eucalyptus nitens plants were stem inoculated with P. cinnamomi and tissue was harvested five days post inoculation. Dual RNA-sequencing, a technique which allows the concurrent detection of both pathogen and host transcripts during infection, was performed. Approximately 1% of the reads mapped to the draft genome of P. cinnamomi while 78% of the reads mapped to the Eucalyptus grandis genome. The highest expressed P. cinnamomi gene in planta was a putative crinkler effector (CRN1). Phylogenetic analysis indicated the high similarity of this P. cinnamomi CRN1 to that of Phytophthora infestans. Some CRN effectors are known to target host nuclei to suppress defense. In the host, over 1400 genes were significantly differentially expressed in comparison to mock inoculated trees, including suites of pathogenesis related (PR) genes. In particular, a PR-9 peroxidase gene with a high similarity to a Carica papaya PR-9 ortholog previously shown to be suppressed upon infection by Phytophthora palmivora was down-regulated two-fold. This PR-9 gene may represent a cross-species effector target during P. cinnamomi infection. This study identified pathogenicity factors, potential manipulation targets, and attempted host defense mechanisms activated by E. nitens that contributed to the susceptible outcome of the interaction. PMID:26973660

  9. Recurrent invasive pneumococcal disease in children--host factors and vaccination response.

    PubMed

    Ingels, Helene Andrea Sinclair

    2015-07-01

    Streptococcus pneumoniae is still a leading cause of septicaemia, pneumonia and meningitis in young children world-wide with over half a million children dying annually from pneumococcal disease.  Some children are prone to repeated episodes of invasive pneumococcal disease (IPD) because of an underlying predisposing disease. Recurrent IPD (rIPD) is a rarity and published reports on rIPD are limited by having few children included, selected groups of patients or short follow-up periods. Deficiencies in the innate or adaptive immune system have been described in children with rIPD, but the frequency of immunodeficiency among such patients is unknown. The aim of this PhD thesis was to examine paediatric cases of laboratory-confirmed rIPD, over a 33-year period in Denmark, to determine risk factors and study aspects of the immunological background for this problem in children. In October 2007, a seven-valent pneumococcal conjugate vaccine (PCV7) was implemented in the Danish infant immunization programme. An additional aim of the thesis was to examine the impact of vaccination on a population level, following the first three years of general PCV7 vaccination in Denmark. The thesis consists of three papers, which are all directly or indirectly based on data retrieved from the National Streptococcus Pneumoniae Registry. This registry is nationwide and dates back to 1938. The registry contains data from all laboratory-confirmed cases of IPD in Denmark and is continually updated for national surveillance. In Paper 1, we conducted a 33-year retrospective nationwide study of paediatric rIPD. By using data from the National Streptococcus Pneumoniae Registry combined with clinical data from hospital records, we could describe one of the largest known cohorts of children (n:59) with rIPD . We covered epidemiological, microbiological, and clinical features of this clinical entity. Of all children experiencing rIPD, 47% had a known predisposing underlying disease at the time of

  10. Incidence, risk factors, and outcome of cytomegalovirus viremia and gastroenteritis in patients with gastrointestinal graft-versus-host disease.

    PubMed

    Bhutani, Divaya; Dyson, Gregory; Manasa, Richard; Deol, Abhinav; Ratanatharathorn, Voravit; Ayash, Lois; Abidi, Muneer; Lum, Lawrence G; Al-Kadhimi, Zaid; Uberti, Joseph P

    2015-01-01

    Gastrointestinal (GI) graft-versus-host disease (GVHD) is one of the most common causes of morbidity and mortality after allogeneic stem cell transplantation. In addition, cytomegalovirus (CMV) infection of the gastrointestinal tract can complicate the post-transplantation course of these patients and it can be difficult to differentiate the 2 diagnoses given that they can present with similar symptoms. We retrospectively analyzed 252 patients who were diagnosed with GI GVHD to evaluate the incidence, risk factors, and outcomes of CMV viremia and CMV gastroenteritis in these patients. The median age at the time of transplantation was 51 years, 35% were related donor transplantations, and 65% were unrelated donor transplantations. A total of 114 (45%) patients developed CMV viremia at a median of 34 days (range, 14 to 236 days) after transplantation. Only recipient CMV IgG serostatus was significantly associated with development of CMV viremia (P < .001). The incidence of CMV viremia with relation to donor (D) and recipient (R) CMV serostatus subgroups was as follows: D+/R+, 73%; D-/R+, 67%; D+/R-, 19%; and D-/R-, 0. A total of 31 patients were diagnosed with a biopsy-proven CMV gastroenteritis; 2 patients had evidence of CMV gastroenteritis and GVHD on the first biopsy and 29 on the second biopsy. Median time to development of CMV gastroenteritis was 52 days (range, 19 to 236 days) after transplantation. Using death as a competing risk, the cumulative incidence of CMV gastroenteritis at 1 year was 16.4%. The incidence of CMV gastroenteritis in relation to the donor/recipient serostatus was as follows: D+/R+, 22%; D-/R+, 31%; D+/R-, 12%; and D-/R-, 0. Median follow-up time for the 252 patients was 35.4 (95% CI 23.8 to 44.8) months. The estimated overall survival rate at 1 and 2 years was .45 (95% confidence interval [CI], .39 to .52) and .39 (95% CI, .33 to .46), respectively. Of the examined variables, those related to the overall survival were maximal clinical

  11. Incidence, Risk Factors, and Outcome of Cytomegalovirus Viremia and Gastroenteritis in Patients with Gastrointestinal Graft-versus-Host Disease

    PubMed Central

    Bhutani, Divaya; Dyson, Gregory; Manasa, Richard; Deol, Abhinav; Ratanatharathorn, Voravit; Ayash, Lois; Abidi, Muneer; Lum, Lawrence G.; Al-Kadhimi, Zaid; Uberti, Joseph P.

    2014-01-01

    Gastrointestinal (GI) graft-versus-host disease (GVHD) is 1 of the most common causes of morbidity and mortality after allogeneic stem cell transplantation. In addition, cytomegalovirus (CMV) infection of the gastrointestinal tract can complicate the post-transplantation course of these patients and it can be difficult to differentiate the 2 diagnoses given that they can present with similar symptoms. We retrospectively analyzed 252 patients who were diagnosed with GI GVHD to evaluate the incidence, risk factors, and outcomes of CMV viremia and CMV gastroenteritis in these patients. The median age at the time of transplantation was 51 years, 35% were related donor transplantations, and 65% were unrelated donor transplantations. A total of 114 (45%) patients developed CMV viremia a median of 34 days (range, 14 to 236 days) after transplantation. Only recipient CMV IgG serostatus was significantly associated with development of CMV viremia (P < .001). The incidence of CMV viremia with relation to donor (D) and recipient (R) CMV serostatus subgroups was as follows: D+/R+, 73%; D−/R+, 67%; D+/R−, 19%; and D−/R−, 0. A total of 31 patients were diagnosed with a biopsy-proven CMV gastroenteritis; 2 patients had evidence of CMV gastroenteritis and GVHD on the first biopsy and 29 on the second biopsy. Median time to development of CMV gastroenteritis was 52 days (range, 19 to 236 days) after transplantation. Using death as a competing risk, the cumulative incidence of CMV gastroenteritis at 1 year was 16.4%. The incidence of CMV gastroenteritis in relation to the donor/recipient serostatus was as follows: D+/R+, 22%; D−/R+, 31%; D+/R−, 12%; and D−/R−, 0. Median overall survival of the 252 patients was 35.4 (range, 23.8 to 44.8) months. The estimated overall survival rate at 1 and 2 years was .45 (95% confidence interval [CI], .39 to .52) and .39 (95% CI, .33 to .46), respectively. Of the examined variables, those related to the overall survival were maximal

  12. Deletion analysis of the fis promoter region in Escherichia coli: antagonistic effects of integration host factor and Fis.

    PubMed Central

    Pratt, T S; Steiner, T; Feldman, L S; Walker, K A; Osuna, R

    1997-01-01

    Fis is a small DNA-binding and -bending protein in Escherichia coli that is involved in several different biological processes, including stimulation of specialized DNA recombination events and regulation of gene expression. fis protein and mRNA levels rapidly increase during early logarithmic growth phase in response to a nutritional upshift but become virtually undetectable during late logarithmic and stationary phases. We present evidence that the growth phase-dependent fis expression pattern is not determined by changes in mRNA stability, arguing in favor of regulation at the level of transcription. DNA deletion analysis of the fis promoter (fis P) region indicated that DNA sequences from -166 to -81, -36 to -26, and +107 to +366 relative to the transcription start site are required for maximum expression. A DNA sequence resembling the integration host factor (IHF) binding site centered approximately at -114 showed DNase I cleavage protection by IHF. In ihf cells, maximum cellular levels of fis mRNA were decreased more than 3-fold and transcription from fis P on a plasmid was decreased about 3.8-fold compared to those in cells expressing wild-type IHF. In addition, a mutation in the ihf binding site resulted in a 76 and 61% reduction in transcription from fis P on a plasmid in the presence or absence of Fis, respectively. Insertions of 5 or 10 bp between this ihf site and fis P suggest that IHF functions in a position-dependent manner. We conclude that IHF plays a role in stimulating transcription from fis P by interacting with a site centered approximately at -114 relative to the start of transcription. We also showed that although the fis P region contains six Fis binding sites, Fis site II (centered at -42) played a predominant role in autoregulation, Fis sites I and III (centered at +26 and -83, respectively) seemingly played smaller roles, and no role in negative autoregulation could be attributed to Fis sites IV, V, and VI (located upstream of site III

  13. Host and Environmental Factors Modulate the Exposure of Free-Ranging and Farmed Red Deer (Cervus elaphus) to Coxiella burnetii

    PubMed Central

    Velasco Ávila, Ana Luisa; Boadella, Mariana; Beltrán-Beck, Beatriz; Barasona, José Ángel; Santos, João P. V.; Queirós, João; García-Pérez, Ana L.; Barral, Marta; Ruiz-Fons, Francisco

    2015-01-01

    The control of multihost pathogens, such as Coxiella burnetii, should rely on accurate information about the roles played by the main hosts. We aimed to determine the involvement of the red deer (Cervus elaphus) in the ecology of C. burnetii. We predicted that red deer populations from broad geographic areas within a European context would be exposed to C. burnetii, and therefore, we hypothesized that a series of factors would modulate the exposure of red deer to C. burnetii. To test this hypothesis, we designed a retrospective survey of 47 Iberian red deer populations from which 1,751 serum samples and 489 spleen samples were collected. Sera were analyzed by enzyme-linked immunosorbent assays (ELISA) in order to estimate exposure to C. burnetii, and spleen samples were analyzed by PCR in order to estimate the prevalence of systemic infections. Thereafter, we gathered 23 variables—within environmental, host, and management factors—potentially modulating the risk of exposure of deer to C. burnetii, and we performed multivariate statistical analyses to identify the main risk factors. Twenty-three populations were seropositive (48.9%), and C. burnetii DNA in the spleen was detected in 50% of the populations analyzed. The statistical analyses reflect the complexity of C. burnetii ecology and suggest that although red deer may maintain the circulation of C. burnetii without third species, the most frequent scenario probably includes other wild and domestic host species. These findings, taken together with previous evidence of C. burnetii shedding by naturally infected red deer, point at this wild ungulate as a true reservoir for C. burnetii and an important node in the life cycle of C. burnetii, at least in the Iberian Peninsula. PMID:26150466

  14. Baculovirus DNA Replication-Specific Expression Factors Trigger Apoptosis and Shutoff of Host Protein Synthesis during Infection▿

    PubMed Central

    Schultz, Kimberly L. W.; Friesen, Paul D.

    2009-01-01

    Apoptosis is an important antivirus defense. To define the poorly understood pathways by which invertebrates respond to viruses by inducing apoptosis, we have identified replication events that trigger apoptosis in baculovirus-infected cells. We used RNA silencing to ablate factors required for multiplication of Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV). Transfection with double-stranded RNA (dsRNA) complementary to the AcMNPV late expression factors (lefs) that are designated as replicative lefs (lef-1, lef-2, lef-3, lef-11, p143, dnapol, and ie-1/ie-0) blocked virus DNA synthesis and late gene expression in permissive Spodoptera frugiperda cells. dsRNAs specific to designated nonreplicative lefs (lef-8, lef-9, p47, and pp31) blocked late gene expression without affecting virus DNA replication. Thus, both classes of lefs functioned during infection as defined. Silencing the replicative lefs prevented AcMNPV-induced apoptosis of Spodoptera cells, whereas silencing the nonreplicative lefs did not. Thus, the activity of replicative lefs or virus DNA replication is sufficient to trigger apoptosis. Confirming this conclusion, AcMNPV-induced apoptosis was suppressed by silencing the replicative lefs in cells from a divergent species, Drosophila melanogaster. Silencing replicative but not nonreplicative lefs also abrogated AcMNPV-induced shutdown of host protein synthesis, suggesting that virus DNA replication triggers inhibition of host biosynthetic processes and that apoptosis and translational arrest are linked. Our findings suggest that baculovirus DNA replication triggers a host cell response similar to the DNA damage response in vertebrates, which causes translational arrest and apoptosis. Pathways for detecting virus invasion and triggering apoptosis may therefore be conserved between insects and mammals. PMID:19706708

  15. Integrating products of Bessel functions with an additional exponential or rational factor

    NASA Astrophysics Data System (ADS)

    Van Deun, Joris; Cools, Ronald

    2008-04-01

    We provide two MATLAB programs to compute integrals of the form ex∏i=1kJν_i(ax)dxand 0∞xr+x∏i=1kJν_i(ax)dx with Jν_i(x) the Bessel function of the first kind and (real) order ν. The parameter m is a real number such that ∑ν+m>-1 (to assure integrability near zero), r is real and the numbers c and a are all strictly positive. The program can deliver accurate error estimates. Program summaryProgram title: BESSELINTR, BESSELINTC Catalogue identifier: AEAH_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEAH_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 1601 No. of bytes in distributed program, including test data, etc.: 13 161 Distribution format: tar.gz Programming language: Matlab (version ⩾6.5), Octave (version ⩾2.1.69) Computer: All supporting Matlab or Octave Operating system: All supporting Matlab or Octave RAM: For k Bessel functions our program needs approximately ( 500+140k) double precision variables Classification: 4.11 Nature of problem: The problem consists in integrating an arbitrary product of Bessel functions with an additional rational or exponential factor over a semi-infinite interval. Difficulties arise from the irregular oscillatory behaviour and the possible slow decay of the integrand, which prevents truncation at a finite point. Solution method: The interval of integration is split into a finite and infinite part. The integral over the finite part is computed using Gauss-Legendre quadrature. The integrand on the infinite part is approximated using asymptotic expansions and this approximation is integrated exactly with the aid of the upper incomplete gamma function. In the case where a rational factor is present, this factor is first expanded in a Taylor series around infinity. Restrictions: Some (and eventually all

  16. Genome-wide CRISPR screen reveals novel host factors required for Staphylococcus aureus α-hemolysin-mediated toxicity

    PubMed Central

    Virreira Winter, Sebastian; Zychlinsky, Arturo; Bardoel, Bart W.

    2016-01-01

    Staphylococcus aureus causes a wide variety of infections and antibiotic resistant strains are a major problem in hospitals. One of the best studied virulence factors of S. aureus is the pore-forming toxin alpha hemolysin (αHL) whose mechanism of action is incompletely understood. We performed a genome-wide loss-of-function screen using CRISPR/Cas9 technology to identify host targets required for αHL susceptibility in human myeloid cells. We found gRNAs for ten genes enriched after intoxication with αHL and focused on the top five hits. Besides a disintegrin and metalloproteinase domain-containing protein 10 (ADAM10), the host receptor for αHL, we identified three proteins, Sys1 golgi trafficking protein (SYS1), ADP-ribosylation factor 1 (ARFRP1), and tetraspanin-14 (TSPAN14) which regulate the presentation of ADAM10 on the plasma membrane post-translationally. Interestingly, we also showed that cells lacking sphingomyelin synthase 1 (SGMS1) resist αHL intoxication, but have only a slightly reduced ADAM10 surface expression. SGMS1 regulates lipid raft formation, suggesting that αHL requires these membrane microdomains for attachment and cytotoxicity. PMID:27066838

  17. Innate immunity in HIV-1 infection: epithelial and non-specific host factors of mucosal immunity- a workshop report.

    PubMed

    Nittayananta, W; Weinberg, A; Malamud, D; Moyes, D; Webster-Cyriaque, J; Ghosh, S

    2016-04-01

    The interplay between HIV-1 and epithelial cells represents a critical aspect in mucosal HIV-1 transmission. Epithelial cells lining the oral cavity cover subepithelial tissues, which contain virus-susceptible host cells including CD4(+) T lymphocytes, monocytes/macrophages, and dendritic cells. Oral epithelia are among the sites of first exposure to both cell-free and cell-associated virus HIV-1 through breast-feeding and oral-genital contact. However, oral mucosa is considered to be naturally resistant to HIV-1 transmission. Oral epithelial cells have been shown to play a crucial role in innate host defense. Nevertheless, it is not clear to what degree these local innate immune factors contribute to HIV-1 resistance of the oral mucosa. This review paper addressed the following issues that were discussed at the 7th World Workshop on Oral Health and Disease in AIDS held in Hyderabad, India, during November 6-9, 2014: (i) What is the fate of HIV-1 after interactions with oral epithelial cells?; (ii) What are the keratinocyte and other anti-HIV effector oral factors, and how do they contribute to mucosal protection?; (iii) How can HIV-1 interactions with oral epithelium affect activation and populations of local immune cells?; (iv) How can HIV-1 interactions alter functions of oral epithelial cells? PMID:27109285

  18. Network analysis of microRNAs, transcription factors, target genes and host genes in human anaplastic astrocytoma

    PubMed Central

    XUE, LUCHEN; XU, ZHIWEN; WANG, KUNHAO; WANG, NING; ZHANG, XIAOXU; WANG, SHANG

    2016-01-01

    Numerous studies have investigated the roles played by various genes and microRNAs (miRNAs) in neoplasms, including anaplastic astrocytoma (AA). However, the specific regulatory mechanisms involving these genes and miRNAs remain unclear. In the present study, associated biological factors (miRNAs, transcription factors, target genes and host genes) from existing studies of human AA were combined methodically through the interactions between genes and miRNAs, as opposed to studying one or several. Three regulatory networks, including abnormally expressed, related and global networks were constructed with the aim of identifying significant gene and miRNA pathways. Each network is composed of three associations between miRNAs targeted at genes, transcription factors (TFs) regulating miRNAs and miRNAs located on their host genes. Among these, the abnormally expressed network, which involves the pathways of previously identified abnormally expressed genes and miRNAs, partially indicated the regulatory mechanism underlying AA. The network contains numerous abnormal regulation associations when AA emerges. By modifying the abnormally expressed network factors to a normal expression pattern, the faulty regulation may be corrected and tumorigenesis of AA may be prevented. Certain specific pathways are highlighted in AA, for example PTEN which is targeted by miR-21 and miR-106b, regulates miR-25 which in turn targets TP53. PTEN and miR-21 have been observed to form feedback loops. Furthermore, by comparing and analyzing the pathway predecessors and successors of abnormally expressed genes and miRNAs in three networks, similarities and differences of regulatory pathways may be identified and proposed. In summary, the present study aids in elucidating the occurrence, mechanism, prevention and treatment of AA. These results may aid further investigation into therapeutic approaches for this disease. PMID:27347075

  19. Factors conditioning the habitat of bilharziasis intermediate hosts of the family Planorbidae

    PubMed Central

    Abdel Malek, Emile

    1958-01-01

    In this article, the author examines certain physical, chemical and biological characteristics of water-bodies which make them suitable or unsuitable as habitats for planorbid snails acting as vectors of bilharziasis. The principal conditioning factors appear to be: amount of food available; extent of the growth of aquatic weeds; oxygen content of the water; amount of sunlight able to penetrate the water; strength of the current; nature of the substratum; ionic composition of the water; and presence or absence of parasites and predators. Several of these factors are interdependent. Although there are differences between the various species in their habitat requirements, their ranges of tolerance were found to overlap greatly. The optimum conditions are similar for all species, but extremes are tolerated better by some species than by others. Theoretically, extremes of certain factors should be capable of eliminating snails from a body of water; in practice such extremes rarely occur, and the absence of vectors must be attributed to the combined effect of several factors. Although certain parasites and predators exterminate vectors in the laboratory, the author considers it unlikely that they would do so in nature, as under laboratory conditions the biological balance is disturbed to the disadvantage of the snail. The data available are still too scanty for an exact assessment to be made of the importance of individual environmental factors in controlling the size of vector populations; but this review of present knowledge indicates the lines along which further investigation can be most profitably pursued. PMID:13573113

  20. Network and pathway analysis of microRNAs, transcription factors, target genes and host genes in human glioma

    PubMed Central

    ZHANG, YING; ZHAO, SHISHUN; XU, ZHIWEN

    2016-01-01

    To date, there has been rapid development with regard to gene and microRNA (miR/miRNA) research in gliomas. However, the regulatory mechanisms of the associated genes and miRNAs remain unclear. In the present study, the genes, miRNAs and transcription factors (TFs) were considered as elements in the regulatory network, and focus was placed on the associations between TFs and miRNAs, miRNAs and target genes, and miRNAs and host genes. In order to show the regulatory correlation clearly, all the elements were investigated and three regulatory networks, namely the differentially-expressed, related and global networks, were constructed. Certain important pathways were highlighted, with analysis of the similarities and differences among the networks. Next, the upstream and downstream elements of differentially-expressed genes, miRNAs and predicted TFs were listed. The most notable aspect of the present study was the three levels of network, particularly the differentially-expressed network, since the differentially-expressed associations that these networks provide appear at the initial stages of cancers such as glioma. If the states of the differentially-expressed associations can be adjusted to the normal state via alterations in regulatory associations, which were also recorded in the study networks and tables, it is likely that cancer can be regulated or even avoided. In the present study, the differentially-expressed network illuminated the pathogenesis of glioma; for example, a TF can regulate one or more miRNAs, and a target gene can be targeted by one or more miRNAs. Therefore, the host genes and target genes, the host genes and TFs, and the target genes and TFs indirectly affect each other through miRNAs. The association also exists between TFs and TFs, target genes and target genes, and host genes and host genes. The present study also demonstrated self-adaption associations and circle-regulations. The related network further described the regulatory mechanism

  1. Stimulated production of steroids in Inonotus obliquus by host factors from birch.

    PubMed

    Wang, Lian-Xia; Lu, Zhen-Ming; Geng, Yan; Zhang, Xiao-Mei; Xu, Guo-Hua; Shi, Jin-Song; Xu, Zheng-Hong

    2014-12-01

    Steroids was considered as one of the bioactive components in Inonotus obliquus, while this kind of secondary metabolites are less accumulated in cultured mycelia. In this study, effect of extracts from bark and core of host-related species, birch (Betula platyphylla Suk.), on steroid production of I. obliquus in submerged culture were evaluated. The results showed that all dosages (0.01 and 0.1 g/L) of aqueous extracts and methanol extracts from birch bark and birch core possessed significantly stimulatory effect on steroid production of I. obliquus (P < 0.05). Among the eight extracts, the aqueous extract (0.01 g/L) from birch bark gave the highest steroid production (225.5 ± 8.7 mg/L), which is 97.3% higher than that of the control group. The aqueous extract (0.01 and 0.1 g/L) from birch bark could simultaneously stimulated mycelial growth and steroid content, while the methanol extract from birch bark only elevated the steroid content. High performance liquid chromatography analysis showed that productions of betulin, ergosterol, cholesterol, lanosterol, stigmasterol, and sitosterol in I. obliquus simultaneously increased in the presence of aqueous extract and methanol extract from birch bark. The results presented herein indicate that extracts from birch bark could act as an inducer for steroid biosynthesis of I. obliquus. PMID:25027706

  2. Tumor-host interactions in the gallbladder suppress distal angiogenesis and tumor growth: involvement of transforming growth factor beta1.

    PubMed

    Gohongi, T; Fukumura, D; Boucher, Y; Yun, C O; Soff, G A; Compton, C; Todoroki, T; Jain, R K

    1999-10-01

    Angiogenesis inhibitors produced by a primary tumor can create a systemic anti-angiogenic environment and maintain metastatic tumor cells in a state of dormancy. We show here that the gallbladder microenvironment modulates the production of transforming growth factor (TGF)-beta1, a multifunctional cytokine that functions as an endogenous anti-angiogenic and anti-tumor factor in a cranial window preparation. We found that a wide variety of human gallbladder tumors express TGF-beta1 irrespective of histologic type. We implanted a gel impregnated with basic fibroblast growth factor or Mz-ChA-2 tumor in the cranial windows of mice without tumors or mice with subcutaneous or gallbladder tumors to study angiogenesis and tumor growth at a secondary site. Angiogenesis, leukocyte-endothelial interaction in vessels and tumor growth in the cranial window were substantially inhibited in mice with gallbladder tumors. The concentration of TGF-beta1 in the plasma of mice with gallbladder tumors was 300% higher than that in the plasma of mice without tumors or with subcutaneous tumors. In contrast, there was no difference in the plasma levels of other anti- and pro-angiogenic factors. Treatment with neutralizing antibody against TGF-beta1 reversed both angiogenesis suppression and inhibition of leukocyte rolling induced by gallbladder tumors. TGF-beta1 also inhibited Mz-ChA-2 tumor cell proliferation. Our results indicate that the production of anti-angiogenesis/proliferation factors is regulated by tumor-host interactions. PMID:10502827

  3. Spatial and seasonal factors are key determinants in the aggregation of helminths in their definitive hosts: Pseudamphistomum truncatum in otters (Lutra lutra).

    PubMed

    Sherrard-Smith, E; Perkins, S E; Chadwick, E A; Cable, J

    2015-01-01

    Parasites are typically aggregated within their host populations. The most heavily infected hosts are frequently cited as targets for optimal disease control. Yet a heavily infected individual is not necessarily highly infective and does not automatically contribute a higher proportion of infective parasitic stages than a host with fewer parasites. Here, Pseudamphistomum truncatum (Opisthorchiida) parasitic infection within the definitive otter host (Lutra lutra) is used as a model system. The hypothesis tested is that variation in parasite abundance, aggregation and egg production (fecundity, as a proxy of host infectivity) can be explained by abiotic (season and region) or biotic (host age, sex and body condition) factors. Parasite abundance was affected most strongly by the biotic factors of age and body condition, such that adults and otters with a higher condition index had heavier infections than sub-adults or those with a lower condition index, whilst there were no significant differences in parasite abundance among the seasons, regions (ecological regions defined by river catchment boundaries) or host sexes. Conversely, parasite aggregation was affected most strongly by the abiotic factors of season and region, which were supported by four different measures of parasite aggregation (the corrected moment estimate k, Taylor's Power Law, the Index of Discrepancy D, and Boulinier's J). Pseudamphistomum truncatum was highly aggregated within otters, with aggregation stronger in the Midlands (England) and Wales than in the southwestern region of the United Kingdom. Overall, more parasites were found in fewer hosts during the summer, which coincides with the summer peak in parasite fecundity. Combined, these data suggest that (i) few otters carry the majority of P. truncatum parasites and that there are more infective stages (eggs) produced during summer; and (ii) abiotic factors are most influential when describing parasite aggregation whilst biotic factors have

  4. Intrinsic host restriction factors of human cytomegalovirus replication and mechanisms of viral escape

    PubMed Central

    Landolfo, Santo; De Andrea, Marco; Dell’Oste, Valentina; Gugliesi, Francesca

    2016-01-01

    Before a pathogen even enters a cell, intrinsic immune defenses are active. This first-line defense is mediated by a variety of constitutively expressed cell proteins collectively termed “restriction factors” (RFs), and they form a vital element of the immune response to virus infections. Over time, however, viruses have evolved in a variety ways so that they are able to overcome these RF defenses via mechanisms that are specific for each virus. This review provides a summary of the universal characteristics of RFs, and goes on to focus on the strategies employed by some of the most important RFs in their attempt to control human cytomegalovirus (HCMV) infection. This is followed by a discussion of the counter-restriction mechanisms evolved by viruses to circumvent the host cell’s intrinsic immune defenses. RFs include nuclear proteins IFN-γ inducible protein 16 (IFI16) (a Pyrin/HIN domain protein), Sp100, promyelocytic leukemia, and hDaxx; the latter three being the keys elements of nuclear domain 10 (ND10). IFI16 inhibits the synthesis of virus DNA by down-regulating UL54 transcription - a gene encoding a CMV DNA polymerase; in response, the virus antagonizes IFI16 via a process involving viral proteins UL97 and pp65 (pUL83), which results in the mislocalizing of IFI16 into the cytoplasm. In contrast, viral regulatory proteins, including pp71 and IE1, seek to modify or disrupt the ND10 proteins and thus block or reverse their inhibitory effects upon virus replication. All in all, detailed knowledge of these HCMV counter-restriction mechanisms will be fundamental for the future development of new strategies for combating HCMV infection and for identifying novel therapeutic agents. PMID:27563536

  5. Bacterial evasion of host immune defense: Yersinia enterocolitica encodes a suppressor for tumor necrosis factor alpha expression.

    PubMed Central

    Beuscher, H U; Rödel, F; Forsberg, A; Röllinghoff, M

    1995-01-01

    The ability of the enteropathogenic Yersinia enterocolitica to survive and proliferate in host tissue depends on a 70-kb plasmid known to encode a number of released Yersinia outer proteins that act as virulence factors by inducing cytotoxicity and inhibiting phagocytosis. This study demonstrates that one of the Yersinia outer proteins, the 41-kDa YopB, suppresses the production of tumor necrosis factor alpha (TNF-alpha), a macrophage-derived cytokine with central roles in the regulation of immune and inflammatory responses to infection. This conclusion is based on several lines of evidence. First, in macrophage cultures, suppression of TNF-alpha mRNA expression was induced by culture supernatant (CS+) of plasmid-bearing yersiniae, the effect which was blocked by anti-YopB antiserum. Second, suppression of TNF-alpha production, but not of interleukin-1 (IL-1) and IL-6, was induced by purified YopB. Third, in Yersinia-infected mice, no increase in TNF-alpha mRNA expression was observed in Peyer's patches, the primary site of bacterial invasion, compared with IL-1 (alpha and beta) mRNA. Finally, administration of anti-YopB antiserum to mice prior to infection with Y. enterocolitica increased TNF activity levels in Peyer's patches and coincided with a reduction in bacterial growth. The results thus provide direct evidence for a secreted eubacterial virulence factor that mediates selective suppression of TNF-alpha production. Although suppression of this single cytokine response is probably not sufficient to facilitate survival of the infecting organisms, the results suggest that suppression of TNF-alpha production by YopB significantly contributes to the evasion of Y. enterocolitica from antibacterial host defense. PMID:7890384

  6. Bacterial modulins: a novel class of virulence factors which cause host tissue pathology by inducing cytokine synthesis.

    PubMed Central

    Henderson, B; Poole, S; Wilson, M

    1996-01-01

    Cytokines are a diverse group of proteins and glycoproteins which have potent and wide-ranging effects on eukaryotic cell function and are now recognized as important mediators of tissue pathology in infectious diseases. It is increasingly recognized that for many bacterial species, cytokine induction is a major virulence mechanism. Until recent years, the only bacterial component known to stimulate cytokine synthesis was lipopolysaccharide (LPS). It is only within the past decade that it has been clearly shown that many components associated with the bacterial cell wall, including proteins, glycoproteins, lipoproteins, carbohydrates, and lipids, have the capacity to stimulate mammalian cells to produce a diverse array of cytokines. It has been established that many of these cytokine-inducing molecules act by mechanisms distinct from that of LPS, and thus their activities are not due to LPS contamination. Bacteria produce a wide range of virulence factors which cause host tissue pathology, and these diverse factors have been grouped into four families: adhesins, aggressins, impedins, and invasins. We suggest that the array of bacterial cytokine-inducing molecules represents a new class of bacterial virulence factor, and, by analogy with the known virulence families, we suggest the term "modulin" to describe these molecules, because the action of cytokines is to modulate eukaryotic cell behavior. This review summarizes our current understanding of cytokine biology in relation to tissue homeostasis and disease and concisely reviews the current literature on the cytokine-inducing molecules produced by gram-negative and gram-positive bacteria, with an emphasis on the cellular mechanisms responsible for cytokine induction. We propose that modulins, by controlling the host immune and inflammatory responses, maintain the large commensal flora that all multicellular organisms support. PMID:8801436

  7. Tumor and Host Factors Controlling Antitumor Immunity and Efficacy of Cancer Immunotherapy

    PubMed Central

    Spranger, Stefani; Sivan, Ayelet; Corrales, Leticia; Gajewski, Thomas F.

    2016-01-01

    Despite recent clinical advances in immunotherapy, a fraction of cancer patients fails to respond to these interventions. Evidence from preclinical mouse models as well as clinical samples has provided evidence that the extent of activated T cell infiltration within the tumor microenvironment is associated with clinical response to immunotherapies including checkpoint blockade. Therefore, understanding the molecular mechanisms mediating the lack of T cell infiltration into the tumor microenvironment will be instrumental for the development of new therapeutic strategies to render those patients immunotherapy responsive. Recent data have suggested that major sources of intersubject heterogeneity include differences in somatic mutations in specific oncogene pathways between cancers of individual subjects and also environmental factors including commensal microbial composition. Successful identification of such causal factors should lead to new therapeutic approaches that may facilitate T cell entry into noninflamed tumors and expand the fraction of patients capable of responding to novel immunotherapies. PMID:26923000

  8. Host immunity to Bacillus anthracis lethal factor and other immunogens: implications for vaccine design.

    PubMed

    Altmann, Daniel M

    2015-03-01

    Infections of humans with Bacillus anthracis are an issue with respect to the biothreat both to civilians and military personnel, infections of individuals by infected livestock in endemic regions and, recently, infections of intravenous drug users injecting anthrax-contaminated heroin. Existing vaccination regimens are reliant on protective antigen neutralization induced by repeated boosts with the AVA or AVP vaccines. However, there is ongoing interest in updated approaches in light of the intensive booster regime and extent of reactogenicity inherent in the current protocols. Several other immunogens from the B. anthracis proteome have been characterized in recent years, including lethal factor. Lethal factor induces strong CD4 T-cell immunity and encompasses immunodominant epitopes of relevance across diverse HLA polymorphisms. Taken together, recent studies emphasize the potential benefits of vaccines able to confer synergistic immunity to protective antigen and to other immunogens, targeting both B-cell and T-cell repertoires. PMID:25400140

  9. Inhibition of host cell RNA polymerase III-mediated transcription by poliovirus: Inactivation of specific transcription factors

    SciTech Connect

    Fradkin, L.G.; Yoshinaga, S.K.; Berk, A.J.; Dasgupta, A.

    1987-11-01

    The inhibition of transcription by RNA polymerase III in poliovirus-infected cells was studied. Experiments utilizing two different cell lines showed that the initiation step of transcription by RNA polymerase III was impaired by infection of these cells with the virus. The observed inhibition of transcription was not due to shut-off of host cell protein synthesis by poliovirus. Among four distinct components required for accurate transcription in vitro from cloned DNA templates, activities of RNA polymerase III and transcription factor TFIIIA were not significantly affected by virus infection. The activity of transcription factor TFIIIC, the limiting component required for transcription of RNA polymerase III genes, was severely inhibited in infected cells, whereas that of transcription factor TFIIIB was inhibited to a lesser extent. The sequence-specific DNA-binding of TFIIIC to the adenovirus VA1 gene internal promoted, however, was not altered by infection of cells with the virus. The authors conclude that (i) at least two transcription factors, TFIIIB and TFIIIC, are inhibited by infection of cells with poliovirtus, (ii) inactivation of TFIIIC does not involve destruction of its DNA-binding domain, and (iii) sequence-specific DNA binding by TFIIIC may be necessary but is not sufficient for the formation of productive transcription complexes.

  10. No Major Host Genetic Risk Factor Contributed to A(H1N1)2009 Influenza Severity.

    PubMed

    Garcia-Etxebarria, Koldo; Bracho, María Alma; Galán, Juan Carlos; Pumarola, Tomàs; Castilla, Jesús; Ortiz de Lejarazu, Raúl; Rodríguez-Dominguez, Mario; Quintela, Inés; Bonet, Núria; Garcia-Garcerà, Marc; Domínguez, Angela; González-Candelas, Fernando; Calafell, Francesc

    2015-01-01

    While most patients affected by the influenza A(H1N1) pandemic experienced mild symptoms, a small fraction required hospitalization, often without concomitant factors that could explain such a severe course. We hypothesize that host genetic factors could contribute to aggravate the disease. To test this hypothesis, we compared the allele frequencies of 547,296 genome-wide single nucleotide polymorphisms (SNPs) between 49 severe and 107 mild confirmed influenza A cases, as well as against a general population sample of 549 individuals. When comparing severe vs. mild influenza A cases, only one SNP was close to the conventional p = 5×10-8. This SNP, rs28454025, sits in an intron of the GSK233 gene, which is involved in a neural development, but seems not to have any connections with immunological or inflammatory functions. Indirectly, a previous association reported with CD55 was replicated. Although sample sizes are low, we show that the statistical power in our design was sufficient to detect highly-penetrant, quasi-Mendelian genetic factors. Hence, and assuming that rs28454025 is likely to be a false positive, no major genetic factor was detected that could explain poor influenza A course. PMID:26379185

  11. No Major Host Genetic Risk Factor Contributed to A(H1N1)2009 Influenza Severity

    PubMed Central

    Garcia-Etxebarria, Koldo; Bracho, María Alma; Galán, Juan Carlos; Pumarola, Tomàs; Castilla, Jesús; Ortiz de Lejarazu, Raúl; Rodríguez-Dominguez, Mario; Quintela, Inés; Bonet, Núria; Garcia-Garcerà, Marc; Domínguez, Angela; González-Candelas, Fernando; Calafell, Francesc

    2015-01-01

    While most patients affected by the influenza A(H1N1) pandemic experienced mild symptoms, a small fraction required hospitalization, often without concomitant factors that could explain such a severe course. We hypothesize that host genetic factors could contribute to aggravate the disease. To test this hypothesis, we compared the allele frequencies of 547,296 genome-wide single nucleotide polymorphisms (SNPs) between 49 severe and 107 mild confirmed influenza A cases, as well as against a general population sample of 549 individuals. When comparing severe vs. mild influenza A cases, only one SNP was close to the conventional p = 5×10−8. This SNP, rs28454025, sits in an intron of the GSK233 gene, which is involved in a neural development, but seems not to have any connections with immunological or inflammatory functions. Indirectly, a previous association reported with CD55 was replicated. Although sample sizes are low, we show that the statistical power in our design was sufficient to detect highly-penetrant, quasi-Mendelian genetic factors. Hence, and assuming that rs28454025 is likely to be a false positive, no major genetic factor was detected that could explain poor influenza A course. PMID:26379185

  12. Tissue Destruction Induced by Porphyromonas gingivalis Infection in a Mouse Chamber Model Is Associated with Host Tumor Necrosis Factor Generation

    PubMed Central

    Lin, Yuh-Yih; Huang, Jan-Hung; Lai, Yo-Yin; Huang, Han-Ching; Hu, Suh-Woan

    2005-01-01

    Intrachamber challenge with Porphyromonas gingivalis strain 381 in a mouse subcutaneous chamber model results in a local infection that progresses to exfoliation of the chambers within 15 days. This study was designed to elucidate the contribution of host reactions to tissue destruction manifested by chamber exfoliation in animals infected with P. gingivalis. Chamber fluids showed increasing levels of prostaglandin E2 with infection, and the levels of tumor necrosis factor (TNF) in chamber fluids peaked just before chamber exfoliation. Intraperitoneal injection of a TNF inhibitor, thalidomide (TH), reduced the number of exfoliated chambers, while indomethacin had no effect. Exogenous TNF in chambers without bacterial infection did not cause chamber exfoliation but induced neutrophil infiltration. In a dual-chamber model, two chambers were implanted in the same mouse. One chamber was infected with P. gingivalis, and 9 days later exogenous TNF was added to the other chamber. Altogether, 66.67% of uninfected chambers were exfoliated between day 11 and day 16, although no bacteria were recovered from uninfected chambers. TH treatment alleviated both infected and uninfected chamber exfoliation. In this study, tissue destruction caused by P. gingivalis 381 infection was due to the elevation of the TNF levels and not due to local bacterial activities. Our results further indicate that local infection by P. gingivalis 381, a nondisseminating strain, actually has systemic effects on the host pathological outcome. PMID:16299286

  13. The Role of Host and Microbial Factors in the Pathogenesis of Pneumococcal Bacteraemia Arising from a Single Bacterial Cell Bottleneck

    PubMed Central

    Furi, Leonardo; Braccini, Tiziana; Manso, Ana Sousa; Pammolli, Andrea; Wang, Bo; Vivi, Antonio; Tassini, Maria; van Rooijen, Nico; Pozzi, Gianni; Ricci, Susanna; Andrew, Peter W.; Koedel, Uwe; Moxon, E. Richard; Oggioni, Marco R.

    2014-01-01

    The pathogenesis of bacteraemia after challenge with one million pneumococci of three isogenic variants was investigated. Sequential analyses of blood samples indicated that most episodes of bacteraemia were monoclonal events providing compelling evidence for a single bacterial cell bottleneck at the origin of invasive disease. With respect to host determinants, results identified novel properties of splenic macrophages and a role for neutrophils in early clearance of pneumococci. Concerning microbial factors, whole genome sequencing provided genetic evidence for the clonal origin of the bacteraemia and identified SNPs in distinct sub-units of F0/F1 ATPase in the majority of the ex vivo isolates. When compared to parental organisms of the inoculum, ex-vivo pneumococci with mutant alleles of the F0/F1 ATPase had acquired the capacity to grow at low pH at the cost of the capacity to grow at high pH. Although founded by a single cell, the genotypes of pneumococci in septicaemic mice indicate strong selective pressure for fitness, emphasising the within-host complexity of the pathogenesis of invasive disease. PMID:24651834

  14. CryoEM analysis of capsid assembly and structural changes upon interactions with a host restriction factor, TRIM5α.

    PubMed

    Zhao, Gongpu; Zhang, Peijun

    2014-01-01

    After virus fusion with a target cell, the viral core is released into the host cell cytoplasm and undergoes a controlled disassembly process, termed uncoating, before or as reverse transcription takes place. The cellular protein TRIM5α is a host cell restriction factor that blocks HIV-1 infection in rhesus macaque cells by targeting the viral capsid and inducing premature uncoating. The molecular mechanism of the interaction between capsid and TRIM5α remains unclear. Here, we describe an approach that utilizes cryo-electron microscopy (cryoEM) to examine the structural changes exerted on HIV-1 capsid (CA) assembly by TRIM5α binding. The TRIM5α interaction sites on CA assembly were further dissected by combining cryoEM with pair-wise cysteine mutations that crosslink CA either within a CA hexamer or between CA hexamers. Based on the structural information from cryoEM and crosslinking results from in vitro CA assemblies and purified intact HIV-1 cores, we demonstrate that direct binding of TRIM5α CC-SPRY domains to the viral capsid results in disruption and fragmentation of the surface lattice of HIV-1 capsid, specifically at inter-hexamer interfaces. The method described here can be easily adopted to study other important interactions in multi-protein complexes. PMID:24158810

  15. Host factors associated with serologic inflammatory markers assessed using multiplex assays.

    PubMed

    McKay, Heather S; Bream, Jay H; Margolick, Joseph B; Martínez-Maza, Otoniel; Phair, John P; Rinaldo, Charles R; Abraham, Alison G; Jacobson, Lisa P

    2016-09-01

    Chronic systemic inflammation contributes to the development of adverse health conditions, yet the influence of fixed and modifiable risk factors on many serologic biomarkers of inflammation remains largely unknown. Serum concentrations of twenty-three biomarkers, including C-reactive protein (CRP), cytokines (CXCL11, CXCL8, CXCL10, CCL2, CCL13, CCL4, CCL17, CXCL13, IL-10, IL-12p70, IL-6, TNF-α, IL-2, IFN-γ, IL-1β, GM-CSF, BAFF), and soluble immune receptors (sCD14, sIL-2Rα, sCD27, sgp130, sTNF-R2) were measured longitudinally using multiplexed immunometric assays in 250 HIV-uninfected men followed in the Multicenter AIDS Cohort Study (1984-2009). Generalized gamma regression was used to determine the statistical significance of factors associated with each biomarker. After accounting for age, race, and education, and for analysis of multiple biomarkers, higher concentrations of specific individual biomarkers were significantly (P<0.002) associated with hypertension, obesity, hepatitis C infection, stimulant use, and diabetes and lower concentrations with hypercholesterolemia. These associations should be taken into account in epidemiological studies of these biomarkers, and may provide potential targets for disease prevention and treatment. PMID:27295613

  16. NIK1, a host factor specialized in antiviral defense or a novel general regulator of plant immunity?

    PubMed

    Machado, Joao P B; Brustolini, Otavio J B; Mendes, Giselle C; Santos, Anésia A; Fontes, Elizabeth P B

    2015-11-01

    NIK1 is a receptor-like kinase involved in plant antiviral immunity. Although NIK1 is structurally similar to the plant immune factor BAK1, which is a key regulator in plant immunity to bacterial pathogens, the NIK1-mediated defenses do not resemble BAK1 signaling cascades. The underlying mechanism for NIK1 antiviral immunity has recently been uncovered. NIK1 activation mediates the translocation of RPL10 to the nucleus, where it interacts with LIMYB to fully down-regulate translational machinery genes, resulting in translation inhibition of host and viral mRNAs and enhanced tolerance to begomovirus. Therefore, the NIK1 antiviral immunity response culminates in global translation suppression, which represents a new paradigm for plant antiviral defenses. Interestingly, transcriptomic analyses in nik1 mutant suggest that NIK1 may suppress antibacterial immune responses, indicating a possible opposite effect of NIK1 in bacterial and viral infections. PMID:26335701

  17. Relative Importance and Additive Effects of Maternal and Infant Risk Factors on Childhood Asthma

    PubMed Central

    Rosas-Salazar, Christian; James, Kristina; Escobar, Gabriel; Gebretsadik, Tebeb; Li, Sherian Xu; Carroll, Kecia N.; Walsh, Eileen; Mitchel, Edward; Das, Suman; Kumar, Rajesh; Yu, Chang; Dupont, William D.; Hartert, Tina V.

    2016-01-01

    Background Environmental exposures that occur in utero and during early life may contribute to the development of childhood asthma through alteration of the human microbiome. The objectives of this study were to estimate the cumulative effect and relative importance of environmental exposures on the risk of childhood asthma. Methods We conducted a population-based birth cohort study of mother-child dyads who were born between 1995 and 2003 and were continuously enrolled in the PRIMA (Prevention of RSV: Impact on Morbidity and Asthma) cohort. The individual and cumulative impact of maternal urinary tract infections (UTI) during pregnancy, maternal colonization with group B streptococcus (GBS), mode of delivery, infant antibiotic use, and older siblings at home, on the risk of childhood asthma were estimated using logistic regression. Dose-response effect on childhood asthma risk was assessed for continuous risk factors: number of maternal UTIs during pregnancy, courses of infant antibiotics, and number of older siblings at home. We further assessed and compared the relative importance of these exposures on the asthma risk. In a subgroup of children for whom maternal antibiotic use during pregnancy information was available, the effect of maternal antibiotic use on the risk of childhood asthma was estimated. Results Among 136,098 singleton birth infants, 13.29% developed asthma. In both univariate and adjusted analyses, maternal UTI during pregnancy (odds ratio [OR] 1.2, 95% confidence interval [CI] 1.18, 1.25; adjusted OR [AOR] 1.04, 95%CI 1.02, 1.07 for every additional UTI) and infant antibiotic use (OR 1.21, 95%CI 1.20, 1.22; AOR 1.16, 95%CI 1.15, 1.17 for every additional course) were associated with an increased risk of childhood asthma, while having older siblings at home (OR 0.92, 95%CI 0.91, 0.93; AOR 0.85, 95%CI 0.84, 0.87 for each additional sibling) was associated with a decreased risk of childhood asthma, in a dose-dependent manner. Compared with vaginal

  18. Quantitative Proteomics Identifies Host Factors Modulated during Acute Hepatitis E Virus Infection in the Swine Model

    PubMed Central

    Rogée, Sophie; Le Gall, Morgane; Chafey, Philippe; Bouquet, Jérôme; Cordonnier, Nathalie; Frederici, Christian

    2014-01-01

    ABSTRACT Hepatitis E virus (HEV) causes acute enterically transmitted hepatitis. In industrialized countries, it is a zoonotic disease, with swine being the major reservoir of human HEV contamination. The occurrence and severity of the disease are variable, with clinical symptoms ranging from asymptomatic to self-limiting acute hepatitis, chronic infection, or fulminant hepatitis. In the absence of a robust cell culture system or small-animal models, the HEV life cycle and pathological process remain unclear. To characterize HEV pathogenesis and virulence mechanisms, a quantitative proteomic analysis was carried out to identify cellular factors and pathways modulated during acute infection of swine. Three groups of pigs were inoculated with three different strains of swine HEV to evaluate the possible role of viral determinants in pathogenesis. Liver samples were analyzed by a differential proteomic approach, two-dimensional difference in gel electrophoresis, and 61 modulated proteins were identified by mass spectroscopy. The results obtained show that the three HEV strains replicate similarly in swine and that they modulate several cellular pathways, suggesting that HEV impairs several cellular processes, which can account for the various types of disease expression. Several proteins, such as heterogeneous nuclear ribonucleoprotein K, apolipoprotein E, and prohibitin, known to be involved in other viral life cycles, were upregulated in HEV-infected livers. Some differences were observed between the three strains, suggesting that HEV's genetic variability may induce variations in pathogenesis. This comparative analysis of the liver proteome modulated during infection with three different strains of HEV genotype 3 provides an important basis for further investigations on the factors involved in HEV replication and the mechanism of HEV pathogenesis. IMPORTANCE Hepatitis E virus (HEV) is responsible for acute hepatitis, with clinical symptoms ranging from asymptomatic

  19. Reciprocal expression of integration host factor and HU in the developmental cycle and infectivity of Legionella pneumophila.

    PubMed

    Morash, Michael G; Brassinga, Ann Karen C; Warthan, Michelle; Gourabathini, Poornima; Garduño, Rafael A; Goodman, Steven D; Hoffman, Paul S

    2009-04-01

    Legionella pneumophila is an intracellular parasite of protozoa that differentiates late in infection into metabolically dormant cysts that are highly infectious. Regulation of this process is poorly understood. Here we report that the small DNA binding regulatory proteins integration host factor (IHF) and HU are reciprocally expressed over the developmental cycle, with HU expressed during exponential phase and IHF expressed postexponentially. To assess the role of these regulatory proteins in development, chromosomal deletions were constructed. Single (ihfA or ihfB) and double deletion (Deltaihf) IHF mutants failed to grow in Acanthamoeba castellanii unless complemented in trans when expressed temporally from the ihfA promoter but not under P(tac) (isopropyl-beta-d-thiogalactopyranoside). In contrast, IHF mutants were infectious for HeLa cells, though electron microscopic examination revealed defects in late-stage cyst morphogenesis (thickened cell wall, intracytoplasmic membranes, and inclusions of poly-beta-hydroxybutyrate), and were depressed for the developmental marker MagA. Green fluorescent protein promoter fusion assays indicated that IHF and the stationary-phase sigma factor RpoS were required for full postexponential expression of magA. Finally, defects in cyst morphogenesis noted for Deltaihf mutants in HeLa cells correlated with a loss of both detergent resistance and hyperinfectivity compared with results for wild-type cysts. These studies establish IHF and HU as markers of developmental stages and show that IHF function is required for both differentiation and full virulence of L. pneumophila in natural amoebic hosts. PMID:19201975

  20. 21 CFR 1311.115 - Additional requirements for two-factor authentication.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... authentication. 1311.115 Section 1311.115 Food and Drugs DRUG ENFORCEMENT ADMINISTRATION, DEPARTMENT OF JUSTICE... requirements for two-factor authentication. (a) To sign a controlled substance prescription, the electronic... authentication protocol that uses two of the following three factors: (1) Something only the practitioner...

  1. 21 CFR 1311.115 - Additional requirements for two-factor authentication.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... authentication. 1311.115 Section 1311.115 Food and Drugs DRUG ENFORCEMENT ADMINISTRATION, DEPARTMENT OF JUSTICE... requirements for two-factor authentication. (a) To sign a controlled substance prescription, the electronic... authentication protocol that uses two of the following three factors: (1) Something only the practitioner...

  2. 21 CFR 1311.115 - Additional requirements for two-factor authentication.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... authentication. 1311.115 Section 1311.115 Food and Drugs DRUG ENFORCEMENT ADMINISTRATION, DEPARTMENT OF JUSTICE... requirements for two-factor authentication. (a) To sign a controlled substance prescription, the electronic... authentication protocol that uses two of the following three factors: (1) Something only the practitioner...

  3. 21 CFR 1311.115 - Additional requirements for two-factor authentication.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... authentication. 1311.115 Section 1311.115 Food and Drugs DRUG ENFORCEMENT ADMINISTRATION, DEPARTMENT OF JUSTICE... requirements for two-factor authentication. (a) To sign a controlled substance prescription, the electronic... authentication protocol that uses two of the following three factors: (1) Something only the practitioner...

  4. [Validation of the modified algorithm for predicting host susceptibility to viruses taking into account susceptibility parameters of primary target cell cultures and natural immunity factors].

    PubMed

    Zhukov, V A; Shishkina, L N; Safatov, A S; Sergeev, A A; P'iankov, O V; Petrishchenko, V A; Zaĭtsev, B N; Toporkov, V S; Sergeev, A N; Nesvizhskiĭ, Iu V; Vorob'ev, A A

    2010-01-01

    The paper presents results of testing a modified algorithm for predicting virus ID50 values in a host of interest by extrapolation from a model host taking into account immune neutralizing factors and thermal inactivation of the virus. The method was tested for A/Aichi/2/68 influenza virus in SPF Wistar rats, SPF CD-1 mice and conventional ICR mice. Each species was used as a host of interest while the other two served as model hosts. Primary lung and trachea cells and secretory factors of the rats' airway epithelium were used to measure parameters needed for the purpose of prediction. Predicted ID50 values were not significantly different (p = 0.05) from those experimentally measured in vivo. The study was supported by ISTC/DARPA Agreement 450p. PMID:20608042

  5. Integration host factor and LuxR synergistically bind DNA to coactivate quorum-sensing genes in Vibrio harveyi.

    PubMed

    Chaparian, Ryan R; Olney, Stephen G; Hustmyer, Christine M; Rowe-Magnus, Dean A; van Kessel, Julia C

    2016-09-01

    The cell-cell signaling process called quorum sensing allows bacteria to control behaviors in response to changes in population density. In Vibrio harveyi, the master quorum-sensing transcription factor LuxR is a member of the TetR family of transcription factors that both activates and represses genes to coordinate group behaviors, including bioluminescence. Here, we show that integration host factor (IHF) is a key coactivator of the luxCDABE bioluminescence genes that is required together with LuxR for precise timing and expression levels of bioluminescence during quorum sensing. IHF binds to multiple sites in the luxCDABE promoter and bends the DNA in vitro. IHF and LuxR synergistically bind luxCDABE promoter DNA at overlapping, essential binding sites that are required for maximal gene expression in vivo. RNA-seq analysis demonstrated that IHF regulates 300 genes in V. harveyi, and among these are a core set of 19 genes that are also directly bound and regulated by LuxR. We validated these global analyses by demonstrating that both IHF and LuxR are required for transcriptional activation of the osmotic stress response genes betIBA-proXWV. These data suggest that IHF plays an integral role in one mechanism of transcriptional activation by the LuxR-type family of quorum-sensing regulators in vibrios. PMID:27191515

  6. Structural Basis of the Novel S. pneumoniae Virulence Factor, GHIP, a Glycosyl Hydrolase 25 Participating in Host-Cell Invasion

    PubMed Central

    Niu, Siqiang; Luo, Miao; Tang, Jian; Zhou, Hua; Zhang, Yangli; Min, Xun; Cai, Xuefei; Zhang, Wenlu; Xu, Wenchu; Li, Defeng; Ding, Jingjin; Hu, Yonglin; Wang, Dacheng; Huang, Ailong

    2013-01-01

    Pathogenic bacteria produce a wide variety of virulence factors that are considered to be potential antibiotic targets. In this study, we report the crystal structure of a novel S. pneumoniae virulence factor, GHIP, which is a streptococcus-specific glycosyl hydrolase. This novel structure exhibits an α/β-barrel fold that slightly differs from other characterized hydrolases. The GHIP active site, located at the negatively charged groove in the barrel, is very similar to the active site in known peptidoglycan hydrolases. Functionally, GHIP exhibited weak enzymatic activity to hydrolyze the PNP-(GlcNAc)5 peptidoglycan by the general acid/base catalytic mechanism. Animal experiments demonstrated a marked attenuation of S. pneumoniae-mediated virulence in mice infected by ΔGHIP-deficient strains, suggesting that GHIP functions as a novel S. pneumoniae virulence factor. Furthermore, GHIP participates in allowing S. pneumoniae to colonize the nasopharynx and invade host epithelial cells. Taken together, these findings suggest that GHIP can potentially serve as an antibiotic target to effectively treat streptococcus-mediated infection. PMID:23874703

  7. Global analysis of ion dependence unveils hidden steps in DNA binding and bending by integration host factor

    NASA Astrophysics Data System (ADS)

    Vivas, Paula; Velmurugu, Yogambigai; Kuznetsov, Serguei V.; Rice, Phoebe A.; Ansari, Anjum

    2013-09-01

    Proteins that recognize and bind to specific sites on DNA often distort the DNA at these sites. The rates at which these DNA distortions occur are considered to be important in the ability of these proteins to discriminate between specific and nonspecific sites. These rates have proven difficult to measure for most protein-DNA complexes in part because of the difficulty in separating the kinetics of unimolecular conformational rearrangements (DNA bending and kinking) from the kinetics of bimolecular complex association and dissociation. A notable exception is the Integration Host Factor (IHF), a eubacterial architectural protein involved in chromosomal compaction and DNA recombination, which binds with subnanomolar affinity to specific DNA sites and bends them into sharp U-turns. The unimolecular DNA bending kinetics has been resolved using both stopped-flow and laser temperature-jump perturbation. Here we expand our investigation by presenting a global analysis of the ionic strength dependence of specific binding affinity and relaxation kinetics of an IHF-DNA complex. This analysis enables us to obtain each of the underlying elementary rates (DNA bending/unbending and protein-DNA association/dissociation), and their ionic strength dependence, even under conditions where the two processes are coupled. Our analysis indicates interesting differences in the ionic strength dependence of the bi- versus unimolecular steps. At moderate [KCl] (100-500 mM), nearly all the ionic strength dependence to the overall equilibrium binding affinity appears in the bimolecular association/dissociation of an initial, presumably weakly bent, encounter complex, with a slope SKbi ≈ 8 describing the loglog-dependence of the equilibrium constant to form this complex on [KCl]. In contrast, the unimolecular equilibrium constant to form the fully wrapped specific complex from the initial complex is nearly independent of [KCl], with SKuni < 0.5. This result is counterintuitive because there

  8. Reduced Simian Immunodeficiency Virus Replication in Macrophages of Sooty Mangabeys Is Associated with Increased Expression of Host Restriction Factors

    PubMed Central

    Mir, Kiran D.; Mavigner, Maud; Wang, Charlene; Paiardini, Mirko; Sodora, Donald L.; Chahroudi, Ann M.; Bosinger, Steven E.

    2015-01-01

    ABSTRACT Macrophages are target cells of HIV/SIV infection that may play a role in AIDS pathogenesis and contribute to the long-lived reservoir of latently infected cells during antiretroviral therapy (ART). In previous work, we and others have shown that during pathogenic SIV infection of rhesus macaques (RMs), rapid disease progression is associated with high levels of in vivo macrophage infection. In contrast, during nonpathogenic SIV infection of sooty mangabeys (SMs), neither spontaneous nor experimental CD4+ T cell depletion results in substantial levels of in vivo macrophage infection. To test the hypothesis that SM macrophages are intrinsically more resistant to SIV infection than RM macrophages, we undertook an in vitro comparative assessment of monocyte-derived macrophages (MDMs) from both nonhuman primate species. Using the primary isolate SIVM949, which replicates well in lymphocytes from both RMs and SMs, we found that infection of RM macrophages resulted in persistent SIV-RNA production while SIV-RNA levels in SM macrophage cultures decreased 10- to 100-fold over a similar temporal course of in vitro infection. To explore potential mechanisms responsible for the lower levels of SIV replication and/or production in macrophages from SMs we comparatively assessed, in the two studied species, the expression of the SIV coreceptor as well as the expression of a number of host restriction factors. While previous studies showed that SM monocytes express lower levels of CCR5 (but not CD4) than RM monocytes, the level of CCR5 expression in MDMs was similar in the two species. Interestingly, we found that SM macrophages exhibited a significantly greater increase in the expression of tetherin (P = 0.003) and TRIM22 (P = 0.0006) in response to alpha interferon stimulation and increased expression of multiple host restriction factors in response to lipopolysaccharide stimulation and exposure to SIV. Overall, these findings confirm, in an in vitro infection system

  9. The Symbiosis-Related ERN Transcription Factors Act in Concert to Coordinate Rhizobial Host Root Infection.

    PubMed

    Cerri, Marion R; Frances, Lisa; Kelner, Audrey; Fournier, Joëlle; Middleton, Patrick H; Auriac, Marie-Christine; Mysore, Kirankumar S; Wen, Jiangqi; Erard, Monique; Barker, David G; Oldroyd, Giles E; de Carvalho-Niebel, Fernanda

    2016-06-01

    Legumes improve their mineral nutrition through nitrogen-fixing root nodule symbioses with soil rhizobia. Rhizobial infection of legumes is regulated by a number of transcription factors, including ERF Required for Nodulation1 (ERN1). Medicago truncatula plants defective in ERN1 are unable to nodulate, but still exhibit early symbiotic responses including rhizobial infection. ERN1 has a close homolog, ERN2, which shows partially overlapping expression patterns. Here we show that ern2 mutants exhibit a later nodulation phenotype than ern1, being able to form nodules but with signs of premature senescence. Molecular characterization of the ern2-1 mutation reveals a key role for a conserved threonine for both DNA binding and transcriptional activity. In contrast to either single mutant, the double ern1-1 ern2-1 line is completely unable to initiate infection or nodule development. The strong ern1-1 ern2-1 phenotype demonstrates functional redundancy between these two transcriptional regulators and reveals the essential role of ERN1/ERN2 to coordinately induce rhizobial infection and nodule organogenesis. While ERN1/ERN2 act in concert in the root epidermis, only ERN1 can efficiently allow the development of mature nodules in the cortex, probably through an independent pathway. Together, these findings reveal the key roles that ERN1/ERN2 play at the very earliest stages of root nodule development. PMID:27208242

  10. A Leishmania Ortholog of Macrophage Migration Inhibitory Factor Modulates Host Macrophage Responses1

    PubMed Central

    Kamir, Daniela; Zierow, Swen; Leng, Lin; Cho, Yoonsang; Diaz, Yira; Griffith, Jason; McDonald, Courtney; Merk, Melanie; Mitchell, Robert A.; Trent, John; Chen, Yibang; Kwong, Yuen-Kwan Amy; Xiong, Huabao; Vermeire, Jon; Cappello, Michael; McMahon-Pratt, Diane; Walker, John; Bernhagen, Jurgen; Lolis, Elias; Bucala, Richard

    2009-01-01

    Parasitic organisms have evolved specialized strategies to evade immune defense mechanisms. We describe herein an ortholog of the cytokine, macrophage migration inhibitory factor (MIF), which is produced by the obligate intracellular parasite, Leishmania major. The Leishmania MIF protein, Lm1740MIF, shows significant structural homology with human MIF as revealed by a high-resolution x-ray crystal structure (1.03 Å). Differences between the two proteins in the N-terminal tautomerization site are evident, and we provide evidence for the selective, species-specific inhibition of MIF by small-molecule antagonists that target this site. Lm1740MIF shows significant binding interaction with the MIF receptor, CD74 (Kd = 2.9 × 10−8 M). Like its mammalian counterpart, Lm1740MIF induces ERK1/2 MAP kinase activation in a CD74-dependent manner and inhibits the activation-induced apoptosis of macrophages. The ability of Lm1740MIF to inhibit apoptosis may facilitate the persistence of Leishmania within the macrophage and contribute to its evasion from immune destruction. PMID:18523291

  11. siRNA Screen Identifies Trafficking Host Factors that Modulate Alphavirus Infection.

    PubMed

    Radoshitzky, Sheli R; Pegoraro, Gianluca; Chī, Xi Olì; D Ng, Lián; Chiang, Chih-Yuan; Jozwick, Lucas; Clester, Jeremiah C; Cooper, Christopher L; Courier, Duane; Langan, David P; Underwood, Knashka; Kuehl, Kathleen A; Sun, Mei G; Caì, Yíngyún; Yú, Shu Qìng; Burk, Robin; Zamani, Rouzbeh; Kota, Krishna; Kuhn, Jens H; Bavari, Sina

    2016-03-01

    Little is known about the repertoire of cellular factors involved in the replication of pathogenic alphaviruses. To uncover molecular regulators of alphavirus infection, and to identify candidate drug targets, we performed a high-content imaging-based siRNA screen. We revealed an actin-remodeling pathway involving Rac1, PIP5K1- α, and Arp3, as essential for infection by pathogenic alphaviruses. Infection causes cellular actin rearrangements into large bundles of actin filaments termed actin foci. Actin foci are generated late in infection concomitantly with alphavirus envelope (E2) expression and are dependent on the activities of Rac1 and Arp3. E2 associates with actin in alphavirus-infected cells and co-localizes with Rac1-PIP5K1-α along actin filaments in the context of actin foci. Finally, Rac1, Arp3, and actin polymerization inhibitors interfere with E2 trafficking from the trans-Golgi network to the cell surface, suggesting a plausible model in which transport of E2 to the cell surface is mediated via Rac1- and Arp3-dependent actin remodeling. PMID:27031835

  12. A Leishmania Ortholog of Macrophage Migration Inhibitory Factor Modulates Host Macrophage Responses

    SciTech Connect

    Kamir,D.; Zierow, S.; Leng, L.; Cho, Y.; Diaz, Y.; Griffith, J.; McDonald, C.; Merk, M.; Mitchell, R.; et al

    2008-01-01

    Parasitic organisms have evolved specialized strategies to evade immune defense mechanisms. We describe herein an ortholog of the cytokine, macrophage migration inhibitory factor (MIF), which is produced by the obligate intracellular parasite, Leishmania major. The Leishmania MIF protein, Lm1740MIF, shows significant structural homology with human MIF as revealed by a high-resolution x-ray crystal structure (1.03 A). Differences between the two proteins in the N-terminal tautomerization site are evident, and we provide evidence for the selective, species-specific inhibition of MIF by small-molecule antagonists that target this site. Lm1740MIF shows significant binding interaction with the MIF receptor, CD74 (K(d) = 2.9 x 10(-8) M). Like its mammalian counterpart, Lm1740MIF induces ERK1/2 MAP kinase activation in a CD74-dependent manner and inhibits the activation-induced apoptosis of macrophages. The ability of Lm1740MIF to inhibit apoptosis may facilitate the persistence of Leishmania within the macrophage and contribute to its evasion from immune destruction.

  13. siRNA Screen Identifies Trafficking Host Factors that Modulate Alphavirus Infection

    PubMed Central

    Radoshitzky, Sheli R.; Pegoraro, Gianluca; Chī, Xiǎolì; Dǒng, Lián; Chiang, Chih-Yuan; Jozwick, Lucas; Clester, Jeremiah C.; Cooper, Christopher L.; Courier, Duane; Langan, David P.; Underwood, Knashka; Kuehl, Kathleen A.; Sun, Mei G.; Caì, Yíngyún; Yú, Shuǐqìng; Burk, Robin; Zamani, Rouzbeh; Kota, Krishna; Kuhn, Jens H.; Bavari, Sina

    2016-01-01

    Little is known about the repertoire of cellular factors involved in the replication of pathogenic alphaviruses. To uncover molecular regulators of alphavirus infection, and to identify candidate drug targets, we performed a high-content imaging-based siRNA screen. We revealed an actin-remodeling pathway involving Rac1, PIP5K1- α, and Arp3, as essential for infection by pathogenic alphaviruses. Infection causes cellular actin rearrangements into large bundles of actin filaments termed actin foci. Actin foci are generated late in infection concomitantly with alphavirus envelope (E2) expression and are dependent on the activities of Rac1 and Arp3. E2 associates with actin in alphavirus-infected cells and co-localizes with Rac1–PIP5K1-α along actin filaments in the context of actin foci. Finally, Rac1, Arp3, and actin polymerization inhibitors interfere with E2 trafficking from the trans-Golgi network to the cell surface, suggesting a plausible model in which transport of E2 to the cell surface is mediated via Rac1- and Arp3-dependent actin remodeling. PMID:27031835

  14. Network analysis of microRNAs, transcription factors, target genes and host genes in nasopharyngeal carcinoma

    PubMed Central

    WANG, HAO; XU, ZHIWEN; MA, MENGYAO; WANG, NING; WANG, KUNHAO

    2016-01-01

    Numerous studies on the morbidity of nasopharyngeal carcinoma (NPC) have identified several genes, microRNAs (miRNAs or miRs) and transcription factors (TFs) that influence the pathogenesis of NPC. However, summarizing all the regulatory networks involved in NPC is challenging. In the present study, the genes, miRNAs and TFs involved in NPC were considered as the nodes of the so-called regulatory network, and the associations between them were investigated. To clearly represent these associations, three regulatory networks were built seperately, namely, the differentially expressed network, the associated network and the global network. The differentially expressed network is the most important one of these three networks, since its nodes are differentially expressed genes whose mutations may lead to the development of NPC. Therefore, by modifying the aberrant expression of those genes that are differentially expressed in this network, their dysregulation may be corrected and the tumorigenesis of NPC may thus be prevented. Analysis of the aforementioned three networks highlighted the importance of certain pathways, such as self-adaptation pathways, in the development of NPC. For example, cyclin D1 (CCND1) was observed to regulate Homo sapiens-miR-20a, which in turn targeted CCND1. The present study conducted a systematic analysis of the pathogenesis of NPC through the three aforementioned regulatory networks, and provided a theoretical model for biologists. Future studies are required to evaluate the influence of the highlighted pathways in NPC. PMID:27313701

  15. Gastrointestinal parasites in relation to host traits and group factors in wild meerkats Suricata suricatta.

    PubMed

    Leclaire, Sarah; Faulkner, Charles T

    2014-06-01

    Meerkats are one of the most endearing of South African's wildlife celebrities and one of the most highly studied social mammals. However, although parasites are widely recognized as important regulatory factors in animal population, basic knowledge on meerkats' parasites is lacking. Here 100 fresh fecal samples of wild meerkats were examined for the presence of endoparasitic infection. Endoparasitic taxa identified by the presence of eggs or oocysts included Toxocara suricattae, Oxynema suricattae, Pseudandrya suricattae, Cystoisospora sp. and Eimeria sp. Non-specific diagnoses were made for parasites in the Order Strongylida, Order Spirurida and coccidian based on the morphology and size of the eggs and oocysts. The prevalence of infection with T. suricattae and the strongylate species increased with age, while prevalence of coccidia and intensity of infection by the strongylate species increased with decreasing group size, suggesting that stress associated with living in smaller group may increase susceptibility to parasitism. Moreover, parasite communities were more similar between individuals from the same group than between individuals from different groups, suggesting an important role of the environment in parasite infestation. We did not detect any differences between males and females. This study represents the first detailed report of gastrointestinal parasites in wild meerkats, and is a key starting point for future studies on the effect of endoparasite load in the life history of this species. PMID:24560215

  16. 34 CFR 377.22 - What additional factors does the Secretary consider in making grants?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Secretary considers the following factors in making grants under this program: (a) The diversity of... funded projects. (b) The diversity of clients to be served, in order to ensure that a variety...

  17. 34 CFR 377.22 - What additional factors does the Secretary consider in making grants?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Secretary considers the following factors in making grants under this program: (a) The diversity of... funded projects. (b) The diversity of clients to be served, in order to ensure that a variety...

  18. 34 CFR 377.22 - What additional factors does the Secretary consider in making grants?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Secretary considers the following factors in making grants under this program: (a) The diversity of... funded projects. (b) The diversity of clients to be served, in order to ensure that a variety...

  19. 34 CFR 377.22 - What additional factors does the Secretary consider in making grants?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Secretary considers the following factors in making grants under this program: (a) The diversity of... funded projects. (b) The diversity of clients to be served, in order to ensure that a variety...

  20. 34 CFR 377.22 - What additional factors does the Secretary consider in making grants?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Secretary considers the following factors in making grants under this program: (a) The diversity of... funded projects. (b) The diversity of clients to be served, in order to ensure that a variety...

  1. Lactobacilli and Bifidobacteria in Human Breast Milk: Influence of Antibiotherapy and Other Host and Clinical Factors

    PubMed Central

    Soto, Ana; Martín, Virginia; Jiménez, Esther; Mader, Isabelle; Rodríguez, Juan M.; Fernández, Leonides

    2014-01-01

    ABSTRACT Objective: The objective of this work was to study the lactobacilli and bifidobacteria population in human milk of healthy women, and to investigate the influence that several factors (including antibioteraphy during pregnancy and lactation, country and date of birth, delivery mode, or infant age) may exert on such population. Methods: A total of 160 women living in Germany or Austria provided the breast milk samples. Initially, 66 samples were randomly selected and cultured on MRS-Cys agar plates. Then, the presence of DNA from the genera Lactobacillus and Bifidobacterium, and from most of the Lactobacillus and Bifidobacterium species that were isolated, was assessed by qualitative polymerase chain reaction (PCR) using genus- and species-specific primers. Results: Lactobacilli and bifidobacteria could be isolated from the milk of 27 (40.91%) and 7 (10.61%), respectively, of the 66 cultured samples. On the contrary, Lactobacillus and Bifidobacterium sequences were detected by PCR in 108 (67.50%) and 41 (25.62%), respectively, of the 160 samples analyzed. The Lactobacillus species most frequently isolated and detected was L salivarius (35.00%), followed by L fermentum (25.00%) and L gasseri (21.88%), whereas B breve (13.75%) was the bifidobacterial species most commonly recovered and whose DNA was most regularly found. The number of lactobacilli- or bifidobacteria-positive samples was significantly lower in women who had received antibiotherapy during pregnancy or lactation. Conclusions: Our results suggest that either the presence of lactobacilli and/or bifidobacteria or their DNA may constitute good markers of a healthy human milk microbiota that has not been altered by the use of antibiotics. PMID:24590211

  2. Reciprocal impact of host factors and Helicobacter pylori genotypes on gastric diseases

    PubMed Central

    Honarmand-Jahromy, Sahar; Siavoshi, Farideh; Malekzadeh, Reza; Nejad Sattari, Taher; Latifi-Navid, Saeid

    2015-01-01

    .2%); vacA s2m1 was the least common genotype (3%). The vacA s1 allele was found to be a risk factor for DU, vacA s2 for CG, and vacA s1 and vacA s2 for GU (all P < 0.05). The vacA s2m2 genotype was associated with the development of CG and GU compared to DU (P < 0.05). No correlation was found between vacA m or cagA and gastric diseases. CONCLUSION: The outcome of H. pylori infection is the result of interaction between bacterial genotypes and the age and sex of infected individuals. PMID:26309357

  3. Genotype is an important determinant factor of host susceptibility to periodontitis in the Collaborative Cross and inbred mouse populations

    PubMed Central

    2013-01-01

    Background Periodontal infection (Periodontitis) is a chronic inflammatory disease, which results in the breakdown of the supporting tissues of the teeth. Previous epidemiological studies have suggested that resistance to chronic periodontitis is controlled to some extent by genetic factors of the host. The aim of this study was to determine the phenotypic response of inbred and Collaborative Cross (CC) mouse populations to periodontal bacterial challenge, using an experimental periodontitis model. In this model, mice are co-infected with Porphyromonas gingivalis and Fusobacterium nucleatum, bacterial strains associated with human periodontal disease. Six weeks following the infection, the maxillary jaws were harvested and analyzed for alveolar bone loss relative to uninfected controls, using computerized microtomography (microCT). Initially, four commercial inbred mouse strains were examined to calibrate the procedure and test for gender effects. Subsequently, we applied the same protocol to 23 lines (at inbreeding generations 10–18) from the newly developed mouse genetic reference population, the Collaborative Cross (CC) to determine heritability and genetic variation of control bone volume prior to infection (CBV, naïve bone volume around the teeth of uninfected mice), and residual bone volume (RBV, bone volume after infection) and loss of bone volume (LBV, the difference between CBV and RBV) following infection. Results BALB/CJ mice were highly susceptible (P<0.05) whereas DBA/2J, C57BL/6J and A/J mice were resistant. Six lines of the tested CC population were susceptible, whereas the remaining lines were resistant to alveolar bone loss. Gender effects on bone volume were tested across the four inbred and 23 CC lines, and found not to be significant. Based on ANOVA analyses, broad-sense heritabilities were statistically significant and equal to 0.4 for CBV and 0.2 for LBV. Conclusions The moderate heritability values indicate that the variation in host

  4. hnRNPL and nucleolin bind LINE-1 RNA and function as host factors to modulate retrotransposition

    PubMed Central

    Peddigari, Suresh; Li, Patrick Wai-Lun; Rabe, Jennifer L.; Martin, Sandra L.

    2013-01-01

    Long INterspersed Element one (LINE-1, or L1), is a widely distributed, autonomous retrotransposon in mammalian genomes. During retrotransposition, L1 RNA functions first as a dicistronic mRNA and then as a template for cDNA synthesis. Previously, we defined internal ribosome entry sequences (IRESs) upstream of both ORFs (ORF1 and ORF2) in the dicistronic mRNA encoded by mouse L1. Here, RNA affinity chromatography was used to isolate cellular proteins that bind these regions of L1 RNA. Four proteins, the heterogeneous nuclear ribonucleoproteins (hnRNPs) R, Q and L, and nucleolin (NCL), appeared to interact specifically with the ORF2 IRES. These were depleted from HeLa cells to examine their effects on L1 IRES-mediated translation and L1 retrotransposition. NCL knockdown specifically reduced the ORF2 IRES activity, L1 and L1-assisted Alu retrotransposition without altering L1 RNA or protein abundance. These findings are consistent with NCL acting as an IRES trans-acting factor (ITAF) for ORF2 translation and hence a positive host factor for L1 retrotransposition. In contrast, hnRNPL knockdown dramatically increased L1 retrotransposition as well as L1 RNA and ORF1 protein, indicating that this cellular protein normally interferes with retrotransposition. Thus, hnRNPL joins a small, but growing list of cellular proteins that are potent negative regulators of L1 retrotransposition. PMID:23161687

  5. hnRNPL and nucleolin bind LINE-1 RNA and function as host factors to modulate retrotransposition.

    PubMed

    Peddigari, Suresh; Li, Patrick Wai-Lun; Rabe, Jennifer L; Martin, Sandra L

    2013-01-01

    Long INterspersed Element one (LINE-1, or L1), is a widely distributed, autonomous retrotransposon in mammalian genomes. During retrotransposition, L1 RNA functions first as a dicistronic mRNA and then as a template for cDNA synthesis. Previously, we defined internal ribosome entry sequences (IRESs) upstream of both ORFs (ORF1 and ORF2) in the dicistronic mRNA encoded by mouse L1. Here, RNA affinity chromatography was used to isolate cellular proteins that bind these regions of L1 RNA. Four proteins, the heterogeneous nuclear ribonucleoproteins (hnRNPs) R, Q and L, and nucleolin (NCL), appeared to interact specifically with the ORF2 IRES. These were depleted from HeLa cells to examine their effects on L1 IRES-mediated translation and L1 retrotransposition. NCL knockdown specifically reduced the ORF2 IRES activity, L1 and L1-assisted Alu retrotransposition without altering L1 RNA or protein abundance. These findings are consistent with NCL acting as an IRES trans-acting factor (ITAF) for ORF2 translation and hence a positive host factor for L1 retrotransposition. In contrast, hnRNPL knockdown dramatically increased L1 retrotransposition as well as L1 RNA and ORF1 protein, indicating that this cellular protein normally interferes with retrotransposition. Thus, hnRNPL joins a small, but growing list of cellular proteins that are potent negative regulators of L1 retrotransposition. PMID:23161687

  6. Microinjection of Francisella tularensis and Listeria monocytogenes reveals the importance of bacterial and host factors for successful replication.

    PubMed

    Meyer, Lena; Bröms, Jeanette E; Liu, Xijia; Rottenberg, Martin E; Sjöstedt, Anders

    2015-08-01

    Certain intracellular bacteria use the host cell cytosol as the replicative niche. Although it has been hypothesized that the successful exploitation of this compartment requires a unique metabolic adaptation, supportive evidence is lacking. For Francisella tularensis, many genes of the Francisella pathogenicity island (FPI) are essential for intracellular growth, and therefore, FPI mutants are useful tools for understanding the prerequisites of intracytosolic replication. We compared the growth of bacteria taken up by phagocytic or nonphagocytic cells with that of bacteria microinjected directly into the host cytosol, using the live vaccine strain (LVS) of F. tularensis; five selected FPI mutants thereof, i.e., ΔiglA, ΔiglÇ ΔiglG, ΔiglI, and ΔpdpE strains; and Listeria monocytogenes. After uptake in bone marrow-derived macrophages (BMDM), ASC(-/-) BMDM, MyD88(-/-) BMDM, J774 cells, or HeLa cells, LVS, ΔpdpE and ΔiglG mutants, and L. monocytogenes replicated efficiently in all five cell types, whereas the ΔiglA and ΔiglC mutants showed no replication. After microinjection, all 7 strains showed effective replication in J774 macrophages, ASC(-/-) BMDM, and HeLa cells. In contrast to the rapid replication in other cell types, L. monocytogenes showed no replication in MyD88(-/-) BMDM and LVS showed no replication in either BMDM or MyD88(-/-) BMDM after microinjection. Our data suggest that the mechanisms of bacterial uptake as well as the permissiveness of the cytosolic compartment per se are important factors for the intracytosolic replication. Notably, none of the investigated FPI proteins was found to be essential for intracytosolic replication after microinjection. PMID:26034213

  7. Microinjection of Francisella tularensis and Listeria monocytogenes Reveals the Importance of Bacterial and Host Factors for Successful Replication

    PubMed Central

    Meyer, Lena; Bröms, Jeanette E.; Liu, Xijia; Rottenberg, Martin E.

    2015-01-01

    Certain intracellular bacteria use the host cell cytosol as the replicative niche. Although it has been hypothesized that the successful exploitation of this compartment requires a unique metabolic adaptation, supportive evidence is lacking. For Francisella tularensis, many genes of the Francisella pathogenicity island (FPI) are essential for intracellular growth, and therefore, FPI mutants are useful tools for understanding the prerequisites of intracytosolic replication. We compared the growth of bacteria taken up by phagocytic or nonphagocytic cells with that of bacteria microinjected directly into the host cytosol, using the live vaccine strain (LVS) of F. tularensis; five selected FPI mutants thereof, i.e., ΔiglA, ΔiglÇ ΔiglG, ΔiglI, and ΔpdpE strains; and Listeria monocytogenes. After uptake in bone marrow-derived macrophages (BMDM), ASC−/− BMDM, MyD88−/− BMDM, J774 cells, or HeLa cells, LVS, ΔpdpE and ΔiglG mutants, and L. monocytogenes replicated efficiently in all five cell types, whereas the ΔiglA and ΔiglC mutants showed no replication. After microinjection, all 7 strains showed effective replication in J774 macrophages, ASC−/− BMDM, and HeLa cells. In contrast to the rapid replication in other cell types, L. monocytogenes showed no replication in MyD88−/− BMDM and LVS showed no replication in either BMDM or MyD88−/− BMDM after microinjection. Our data suggest that the mechanisms of bacterial uptake as well as the permissiveness of the cytosolic compartment per se are important factors for the intracytosolic replication. Notably, none of the investigated FPI proteins was found to be essential for intracytosolic replication after microinjection. PMID:26034213

  8. Effect of ferrite addition above the base ferrite on the coupling factor of wireless power transfer for vehicle applications

    NASA Astrophysics Data System (ADS)

    Batra, T.; Schaltz, E.; Ahn, S.

    2015-05-01

    Power transfer capability of wireless power transfer systems is highly dependent on the magnetic design of the primary and secondary inductors and is measured quantitatively by the coupling factor. The inductors are designed by placing the coil over a ferrite base to increase the coupling factor and reduce magnetic emissions to the surroundings. Effect of adding extra ferrite above the base ferrite at different physical locations on the self-inductance, mutual inductance, and coupling factor is under investigation in this paper. The addition can increase or decrease the mutual inductance depending on the placement of ferrite. Also, the addition of ferrite increases the self-inductance of the coils, and there is a probability for an overall decrease in the coupling factor. Correct placement of ferrite, on the other hand, can increase the coupling factor relatively higher than the base ferrite as it is closer to the other inductor. Ferrite being a heavy compound of iron increases the inductor weight significantly and needs to be added judiciously. Four zones have been identified in the paper, which shows different sensitivity to addition of ferrite in terms of the two inductances and coupling factor. Simulation and measurement results are presented for different air gaps between the coils and at different gap distances between the ferrite base and added ferrite. This paper is beneficial in improving the coupling factor while adding minimum weight to wireless power transfer system.

  9. Calcifying nanoparticles (nanobacteria): an additional potential factor for urolithiasis in space flight crews.

    PubMed

    Jones, Jeffrey A; Ciftcioglu, Neva; Schmid, Josef F; Barr, Yael R; Griffith, Donald

    2009-01-01

    Spaceflight-induced microgravity appears to be a risk factor for the development of urinary calculi, resulting in urolithiasis during and after spaceflight. Calcifying nanoparticles, or nanobacteria, multiply more rapidly in simulated microgravity and create external shells of calcium phosphate. The question arises whether calcifying nanoparticles are nidi for calculi and contribute to the development of clinically significant urolithiasis in those who are predisposed to the development of urinary calculi because of intrinsic or extrinsic factors. This case report describes a calculus recovered after flight from an astronaut that, on morphologic and immunochemical analysis (including specific monoclonal antibody staining), demonstrated characteristics of calcifying nanoparticles. PMID:18718644

  10. siRNA Screening Identifies the Host Hexokinase 2 (HK2) Gene as an Important Hypoxia-Inducible Transcription Factor 1 (HIF-1) Target Gene in Toxoplasma gondii-Infected Cells

    PubMed Central

    Menendez, Matthew T.; Teygong, Crystal; Wade, Kristin; Florimond, Celia

    2015-01-01

    ABSTRACT Although it is established that oxygen availability regulates cellular metabolism and growth, little is known regarding how intracellular pathogens use host factors to grow at physiological oxygen levels. Therefore, large-scale human small interfering RNA screening was performed to identify host genes important for growth of the intracellular protozoan parasite Toxoplasma gondii at tissue oxygen tensions. Among the genes identified by this screen, we focused on the hexokinase 2 (HK2) gene because its expression is regulated by hypoxia-inducible transcription factor 1 (HIF-1), which is important for Toxoplasma growth. Toxoplasma increases host HK2 transcript and protein levels in a HIF-1-dependent manner. In addition, parasite growth at 3% oxygen is restored in HIF-1-deficient cells transfected with HK2 expression plasmids. Both HIF-1 activation and HK2 expression were accompanied by increases in host glycolytic flux, suggesting that enhanced HK2 expression in parasite-infected cells is functionally significant. Parasite dependence on host HK2 and HIF-1 expression is not restricted to transformed cell lines, as both are required for parasite growth in nontransformed C2C12 myoblasts and HK2 is upregulated in vivo following infection. While HK2 is normally associated with the cytoplasmic face of the outer mitochondrial membrane at physiological O2 levels, HK2 relocalizes to the host cytoplasm following infection, a process that is required for parasite growth at 3% oxygen. Taken together, our findings show that HIF-1-dependent expression and relocalization of HK2 represent a novel mechanism by which Toxoplasma establishes its replicative niche at tissue oxygen tensions. PMID:26106078

  11. Identification of the Key Weather Factors Affecting Overwintering Success of Apolygus lucorum Eggs in Dead Host Tree Branches

    PubMed Central

    Pan, Hongsheng; Liu, Bing; Lu, Yanhui; Desneux, Nicolas

    2014-01-01

    Understanding the effects of weather on insect population dynamics is crucial to simulate and forecast pest outbreaks, which is becoming increasingly important with the effects of climate change. The mirid bug Apolygus lucorum is an important pest on cotton, fruit trees and other crops in China, and primarily lays its eggs on dead parts of tree branches in the fall for subsequent overwintering. As such, the eggs that hatch the following spring are most strongly affected by ambient weather factors, rather than by host plant biology. In this study, we investigated the effects of three major weather factors: temperature, relative humidity and rainfall, on the hatching rate of A. lucorum eggs overwintering on dead branches of Chinese date tree (Ziziphus jujuba). Under laboratory conditions, rainfall (simulated via soaking) was necessary for the hatching of overwintering A. lucorum eggs. In the absence of rainfall (unsoaked branches), very few nymphs successfully emerged under any of the tested combinations of temperature and relative humidity. In contrast, following simulated rainfall, the hatching rate of the overwintering eggs increased dramatically. Hatching rate and developmental rate were positively correlated with relative humidity and temperature, respectively. Under field conditions, the abundance of nymphs derived from overwintering eggs was positively correlated with rainfall amount during the spring seasons of 2009–2013, while the same was not true for temperature and relative humidity. Overall, our findings indicate that rainfall is the most important factor affecting the hatching rate of overwintering A. lucorum eggs on dead plant parts and nymph population levels during the spring season. It provides the basic information for precisely forecasting the emergence of A. lucorum and subsequently timely managing its population in spring, which will make it possible to regional control of this insect pest widely occurring in multiple crops in summer. PMID

  12. A Granulin-Like Growth Factor Secreted by the Carcinogenic Liver Fluke, Opisthorchis viverrini, Promotes Proliferation of Host Cells

    PubMed Central

    Smout, Michael J.; Laha, Thewarach; Mulvenna, Jason; Sripa, Banchob; Suttiprapa, Sutas; Jones, Alun; Brindley, Paul J.; Loukas, Alex

    2009-01-01

    The human liver fluke, Opisthorchis viverrini, infects millions of people throughout south-east Asia and is a major cause of cholangiocarcinoma, or cancer of the bile ducts. The mechanisms by which chronic infection with O. viverrini results in cholangiocarcinogenesis are multi-factorial, but one such mechanism is the secretion of parasite proteins with mitogenic properties into the bile ducts, driving cell proliferation and creating a tumorigenic environment. Using a proteomic approach, we identified a homologue of human granulin, a potent growth factor involved in cell proliferation and wound healing, in the excretory/secretory (ES) products of the parasite. O. viverrini granulin, termed Ov-GRN-1, was expressed in most parasite tissues, particularly the gut and tegument. Furthermore, Ov-GRN-1 was detected in situ on the surface of biliary epithelial cells of hamsters experimentally infected with O. viverrini. Recombinant Ov-GRN-1 was expressed in E. coli and refolded from inclusion bodies. Refolded protein stimulated proliferation of murine fibroblasts at nanomolar concentrations, and proliferation was inhibited by the MAPK kinase inhibitor, U0126. Antibodies raised to recombinant Ov-GRN-1 inhibited the ability of O. viverrini ES products to induce proliferation of murine fibroblasts and a human cholangiocarcinoma cell line in vitro, indicating that Ov-GRN-1 is the major growth factor present in O. viverrini ES products. This is the first report of a secreted growth factor from a parasitic worm that induces proliferation of host cells, and supports a role for this fluke protein in establishment of a tumorigenic environment that may ultimately manifest as cholangiocarcinoma. PMID:19816559

  13. Factor analysis models for structuring covariance matrices of additive genetic effects: a Bayesian implementation

    PubMed Central

    de los Campos, Gustavo; Gianola, Daniel

    2007-01-01

    Multivariate linear models are increasingly important in quantitative genetics. In high dimensional specifications, factor analysis (FA) may provide an avenue for structuring (co)variance matrices, thus reducing the number of parameters needed for describing (co)dispersion. We describe how FA can be used to model genetic effects in the context of a multivariate linear mixed model. An orthogonal common factor structure is used to model genetic effects under Gaussian assumption, so that the marginal likelihood is multivariate normal with a structured genetic (co)variance matrix. Under standard prior assumptions, all fully conditional distributions have closed form, and samples from the joint posterior distribution can be obtained via Gibbs sampling. The model and the algorithm developed for its Bayesian implementation were used to describe five repeated records of milk yield in dairy cattle, and a one common FA model was compared with a standard multiple trait model. The Bayesian Information Criterion favored the FA model. PMID:17897592

  14. Binding of Host Factors Influences Internalization and Intracellular Trafficking of Streptococcus uberis in Bovine Mammary Epithelial Cells

    PubMed Central

    Almeida, Raul A.; Dunlap, John R.; Oliver, Stephen P.

    2010-01-01

    We showed that internalization of Streptococcus uberis into bovine mammary epithelial cells occurred through receptor- (RME) and caveolae-mediated endocytosis (CME). We reported also that treatment of S. uberis with host proteins including lactoferrin (LF) enhanced its internalization into host cells. Since the underlying mechanism(s) involved in such enhancement was unknown we investigated if preincubation of S. uberis with host proteins drives internalization of this pathogen into host cells through CME. Thus, experiments involving coculture of collagen-, fibronectin-, and LF-pretreated S. uberis with bovine mammary epithelial cells treated with RME and CME inhibitors were conducted. Results showed that internalization of host proteins-pretreated S. uberis into mammary epithelial cells treated with RME inhibitors was higher than that of untreated controls. These results suggest that pretreatment with selected host proteins commits S. uberis to CME, thus avoiding intracellular bactericidal mechanisms and allowing its persistence into bovine mammary epithelial cells. PMID:20614000

  15. Additive relationship between serum fibroblast growth factor 21 level and coronary artery disease

    PubMed Central

    2013-01-01

    Background Expression and activity of the fibroblast growth factor (FGF) 21 hormone-like protein are associated with development of several metabolic disorders. This study was designed to investigate whether serum FGF21 level was also associated with the metabolic syndrome-related cardiovascular disease, atherosclerosis, and its clinical features in a Chinese cohort. Methods Two-hundred-and-fifty-three subjects visiting the Cardiology Department (Sixth People's Hospital affiliated to Shanghai JiaoTong University) were examined by coronary arteriography (to diagnose coronary artery disease (CAD)) and hepatic ultrasonography (to diagnose non-alcoholic fatty liver disease (NAFLD)). Serum FGF21 level was measured by enzyme-linked immunosorbent assay and analyzed for correlation to subject and clinical characteristics. The independent factors of CAD were determined by multivariate logistic regression analysis. Results Subjects with NAFLD showed significantly higher serum FGF21 than those without NAFLD (388.0 pg/mL (253.0-655.4) vs. 273.3 pg/mL (164.9-383.7), P < 0.01). Subjects with CAD showed significantly higher serum FGF21, regardless of NAFLD diagnosis (P < 0.05). Serum FGF21 level significantly elevated with the increasing number of metabolic disorders (P for trend < 0.01). After adjustment of age, sex, and BMI, FGF21 was positively correlated with total cholesterol (P < 0.05) and triglyceride (P < 0.01). FGF21 was identified as an independent factor of CAD (odds ratio = 2.984, 95% confidence interval: 1.014-8.786, P < 0.05). Conclusions Increased level of serum FGF21 is associated with NAFLD, metabolic disorders and CAD. PMID:23981342

  16. Molecular cloning and expression of an additional epidermal growth factor receptor-related gene.

    PubMed Central

    Plowman, G D; Whitney, G S; Neubauer, M G; Green, J M; McDonald, V L; Todaro, G J; Shoyab, M

    1990-01-01

    Epidermal growth factor (EGF), transforming growth factor alpha (TGF-alpha), and amphiregulin are structurally and functionally related growth regulatory proteins. These secreted polypeptides all bind to the 170-kDa cell-surface EGF receptor, activating its intrinsic kinase activity. However, amphiregulin exhibits different activities than EGF and TGF-alpha in a number of biological assays. Amphiregulin only partially competes with EGF for binding EGF receptor, and amphiregulin does not induce anchorage-independent growth of normal rat kidney cells (NRK) in the presence of TGF-beta. Amphiregulin also appears to abrogate the stimulatory effect of TGF-alpha on the growth of several aggressive epithelial carcinomas that overexpress EGF receptor. These findings suggest that amphiregulin may interact with a separate receptor in certain cell types. Here we report the cloning of another member of the human EGF receptor (HER) family of receptor tyrosine kinases, which we have named "HER3/ERRB3." The cDNA was isolated from a human carcinoma cell line, and its 6-kilobase transcript was identified in various human tissues. We have generated peptide-specific antisera that recognizes the 160-kDa HER3 protein when transiently expressed in COS cells. These reagents will allow us to determine whether HER3 binds amphiregulin or other growth regulatory proteins and what role HER3 protein plays in the regulation of cell growth. Images PMID:2164210

  17. 34 CFR 359.32 - What additional factors does the Secretary consider in making a grant under this program?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 2 2010-07-01 2010-07-01 false What additional factors does the Secretary consider in making a grant under this program? 359.32 Section 359.32 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION DISABILITY AND...

  18. 34 CFR 359.32 - What additional factors does the Secretary consider in making a grant under this program?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 34 Education 2 2014-07-01 2013-07-01 true What additional factors does the Secretary consider in making a grant under this program? 359.32 Section 359.32 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION DISABILITY AND...

  19. 34 CFR 359.32 - What additional factors does the Secretary consider in making a grant under this program?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 34 Education 2 2012-07-01 2012-07-01 false What additional factors does the Secretary consider in making a grant under this program? 359.32 Section 359.32 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION DISABILITY AND...

  20. Host genetic factors in American cutaneous leishmaniasis: a critical appraisal of studies conducted in an endemic area of Brazil.

    PubMed

    Castellucci, Léa Cristina; Almeida, Lucas Frederico de; Jamieson, Sarra Elisabeth; Fakiola, Michaela; Carvalho, Edgar Marcelino de; Blackwell, Jenefer Mary

    2014-06-01

    American cutaneous leishmaniasis (ACL) is a vector-transmitted infectious disease with an estimated 1.5 million new cases per year. In Brazil, ACL represents a significant public health problem, with approximately 30,000 new reported cases annually, representing an incidence of 18.5 cases per 100,000 inhabitants. Corte de Pedra is in a region endemic for ACL in the state of Bahia (BA), northeastern Brazil, with 500-1,300 patients treated annually. Over the last decade, population and family-based candidate gene studies were conducted in Corte de Pedra, founded on previous knowledge from studies on mice and humans. Notwithstanding limitations related to sample size and power, these studies contribute important genetic biomarkers that identify novel pathways of disease pathogenesis and possible new therapeutic targets. The present paper is a narrative review about ACL immunogenetics in BA, highlighting in particular the interacting roles of the wound healing gene FLI1 with interleukin-6 and genes SMAD2 and SMAD3 of the transforming growth factor beta signalling pathway. This research highlights the need for well-powered genetic and functional studies on Leishmania braziliensis infection as essential to define and validate the role of host genes in determining resistance/susceptibility regarding this disease. PMID:24863979

  1. Experimental induced avian E. coli salpingitis: Significant impact of strain and host factors on the clinical and pathological outcome.

    PubMed

    Olsen, Rikke Heidemann; Thøfner, Ida Cecilie Naundrup; Pors, Susanne Elisabeth; Pires Dos Santos, Teresa; Christensen, Jens Peter

    2016-05-30

    Several types of Escherichia coli have been associated with extra-intestinal infections in poultry, however, they may vary significantly in their virulence potential. The aim of the present study was to investigate the virulence of five strains of E. coli obtained from different disease manifestations or from the cloacae of a healthy chicken. The virulence potential of the strains were evaluated in an avian experimental model for ascending infections, and experiments were conducted in both layers and broiler breeders. The clinical outcome of infection was highly depending on the challenge strain, however, not significantly reflecting the origin of the strain. In general, broiler breeders had a more severe clinical outcomes of infection compared to layers, but major with-in group diversity was observed for all challenge strains of clinical origin. A single strain of ST95 (phylogroup B2) had a distinct ability to cause disease. Results of the study shows major differences in virulence of different strains of E. coli in ascending infections; however, there was no indication of tissue-specific adaptation, since strains obtained from lesions unrelated to the reproductive system were fully capable of causing experimental infection. In conclusion, the study provides evidence for the clinical outcome of infection with E. coli in poultry is largely influenced by the specific strain as well as individual host factors. PMID:27139030

  2. Manipulation of host factors optimizes the pathogenesis of western equine encephalitis virus infections in mice for antiviral drug development.

    PubMed

    Blakely, Pennelope K; Delekta, Phillip C; Miller, David J; Irani, David N

    2015-02-01

    While alphaviruses spread naturally via mosquito vectors, some can also be transmitted as aerosols making them potential bioterrorism agents. One such pathogen, western equine encephalitis virus (WEEV), causes fatal human encephalitis via multiple routes of infection and thus presumably via multiple mechanisms. Although WEEV also produces acute encephalitis in non-human primates, a small animal model that recapitulates features of human disease would be useful for both pathogenesis studies and to evaluate candidate antiviral therapies. We have optimized conditions to infect mice with a low passage isolate of WEEV, thereby allowing detailed investigation of virus tropism, replication, neuroinvasion, and neurovirulence. We find that host factors strongly influence disease outcome, and in particular, that age, gender, and genetic background all have significant effects on disease susceptibility independent of virus tropism or replication within the central nervous system. Our data show that experimental variables can be adjusted in mice to recapitulate disease features known to occur in both non-human primates and humans, thus aiding further study of WEEV pathogenesis and providing a realistic therapeutic window for antiviral drug delivery. PMID:25361697

  3. Manipulation of host factors optimizes the pathogenesis of western equine encephalitis virus infections in mice for antiviral drug development

    PubMed Central

    Blakely, Pennelope K.; Delekta, Phillip C.; Miller, David J.; Irani, David N.

    2014-01-01

    While alphaviruses spread naturally via mosquito vectors, some can also be transmitted as aerosols making them potential bioterrorism agents. One such pathogen, western equine encephalitis virus (WEEV), causes fatal human encephalitis via multiple routes of infection and thus presumably via multiple mechanisms. Although WEEV also produces acute encephalitis in non-human primates, a small animal model that recapitulates features of human disease would be useful for both pathogenesis studies and to evaluate candidate antiviral therapies. We have optimized conditions to infect mice with a low passage isolate of WEEV, thereby allowing detailed investigation of virus tropism, replication, neuroinvasion, and neurovirulence. We find that host factors strongly influence disease outcome, and in particular that age, gender and genetic background all have significant effects on disease susceptibility independent of virus tropism or replication within the central nervous system. Our data show that experimental variables can be adjusted in mice to recapitulate disease features known to occur in both non-human primates and humans, thus aiding further study of WEEV pathogenesis and providing a realistic therapeutic window for antiviral drug delivery. PMID:25361697

  4. Simultaneous Identification of Potential Pathogenicity Factors of Mycoplasma agalactiae in the Natural Ovine Host by Negative Selection

    PubMed Central

    Hegde, Shivanand; Hegde, Shrilakshmi; Zimmermann, Martina; Flöck, Martina; Spergser, Joachim; Rosengarten, Renate

    2015-01-01

    Mycoplasmas possess complex pathogenicity determinants that are largely unknown at the molecular level. Mycoplasma agalactiae serves as a useful model to study the molecular basis of mycoplasma pathogenicity. The generation and in vivo screening of a transposon mutant library of M. agalactiae were employed to unravel its host colonization factors. Tn4001mod mutants were sequenced using a novel sequencing method, and functionally heterogeneous pools containing 15 to 19 selected mutants were screened simultaneously through two successive cycles of sheep intramammary infections. A PCR-based negative selection method was employed to identify mutants that failed to colonize the udders and draining lymph nodes in the animals. A total of 14 different mutants found to be absent from ≥95% of samples were identified and subsequently verified via a second round of stringent confirmatory screening where 100% absence was considered attenuation. Using this criterion, seven mutants with insertions in genes MAG1050, MAG2540, MAG3390, uhpT, eutD, adhT, and MAG4460 were not recovered from any of the infected animals. Among the attenuated mutants, many contain disruptions in hypothetical genes, implying their previously unknown role in M. agalactiae pathogenicity. These data indicate the putative role of functionally different genes, including hypothetical ones, in the pathogenesis of M. agalactiae. Defining the precise functions of the identified genes is anticipated to increase our understanding of M. agalactiae infections and to develop successful intervention strategies against it. PMID:25916984

  5. Correlation of biological activity with computationally derived structural features from transmembrane hetero-dimers of HIV-1 Vpu with host factors.

    PubMed

    Li, Li-Hua; Fischer, Wolfgang B

    2014-04-01

    Vpu is an 81 amino acid type I integral membrane protein encoded by human immunodeficiency virus type 1 (HIV-1). It is identified to support viral release by potentially forming ion and substrate conducting channels and by modulating the function of host factors. The focus is on the interaction of the transmembrane domains of Vpu with those of host factors using a combination of molecular dynamics simulations and docking approach. Binding poses and adopted tilt angles of the dimers are analyzed and correlated with experimentally derived activity data from literature. Vpu activity is driven by dimerization with the host protein via its alanine rim Ala-8/11/15/19. Tight binding is shown by an almost parallel alignment of the helices in the dimers. Less parallel alignment is proposed to correlate with lower activity. This article is part of a Special Issue entitled: Viral Membrane Proteins - Channels for Cellular Networking. PMID:24036078

  6. Additional thyroid dose factor from transportation sources in Russia after the Chernobyl disaster.

    PubMed Central

    Parshkov, E M; Chebotareva, I V; Sokolov, V A; Dallas, C E

    1997-01-01

    Beginning approximately 4 years after the Chernobyl nuclear accident a steady increase in the incidence of thyroid cancer was observed in children and adolescents of the Bryansk Oblast, which received the highest level of radionuclide contaminants in Russia. We examined the spatial relationship between the residence location of patients with identified thyroid cancer (0-18 years old at the time of the accident) and a number of geographic parameters to better account for the etiology of thyroid cancer spatial distribution. Geographic parameters analyzed included spatial distribution of 137Cs and 131I in soil, population demographics, measurements and reconstructions. of absorbed thyroid 131I doses in the population, and maps of major transportation arteries. An interesting finding is the lack of a consistent correlation between the spatial distribution of radionuclides in the soil and thyroid cancer incidence. Instead, most of the thyroid cancer cases were diagnosed in settlements situated on major railways and roads. Correlating population with thyroid cancer cases and transportation arteries reveals a much higher cancer rate on or near major roads and railways than at a distance from them, again independent of radionuclide soil concentration. There are other important factors, of course, that must be considered in future evaluations of this phenomenon. These include the influence of iodine endemic zones, genetic predisposition to thyroid cancer, and duration of residence time in contaminated areas. The feasibility of radionuclide transport on railways and roads is discussed, together with the vectors for transfer of the contaminants to the human population. Developing a model to reconstruct the radiation dose to the thyroid over time in this geographic region is proposed in light of the impact of transportation arteries. Specific studies are outlined to provide the data necessary to develop this model as well as to better characterize the feasibility and

  7. Polymorphism of adhesion molecule CD31 is not a significant risk factor for graft-versus-host disease.

    PubMed

    Nichols, W C; Antin, J H; Lunetta, K L; Terry, V H; Hertel, C E; Wheatley, M A; Arnold, N D; Siemieniak, D R; Boehnke, M; Ginsburg, D

    1996-12-15

    Mismatch between bone marrow transplant (BMT) patient and donor for an amino acid polymorphism within the adhesion molecule CD31 has recently been reported to increase risk for the development of graft-versus-host disease (GVHD). We further examined this association in a larger series of 301 BMT patients (227 with grade III/IV GVHD and 74 with grade 0 GVHD) and their HLA-identical sibling donors. CD31 genotypes were determined by polymerase chain reaction and restriction endonuclease digestion. The role of mismatch at the CD31 locus in the development of GVHD was assessed by analyzing the extent of CD31 identity and CD31 compatibility among the grade 0 GVHD and grade III/IV GVHD sibling pairs. No significant association between CD31 mismatch and the development of severe GVHD was detected in our overall patient population. Sixty-three percent of grade III/IV GVHD sibling pairs and 69% of grade 0 GVHD sibling pairs had CD31 genotypes that were identical (P = .36, odds ratio = 1.30). In addition, neither the grade 0 GVHD group (P = .10) nor the grade III/IV GVHD group (P = .27) differed significantly from the expected probability of identity between sibling pairs. Mismatch at the CD31 polymorphism between recipients and donors showed no consistent association with the development of GVHD. Current evidence does not support the value of CD31 mismatch in the selection of BMT donors. PMID:8977234

  8. Coagulation Factor IX Mediates Serotype-Specific Binding of Species A Adenoviruses to Host Cells ▿ †

    PubMed Central

    Lenman, Annasara; Müller, Steffen; Nygren, Mari I.; Frängsmyr, Lars; Stehle, Thilo; Arnberg, Niklas

    2011-01-01

    Human species A adenoviruses (HAdVs) comprise three serotypes: HAdV-12, -18, and -31. These viruses are common pathogens and cause systemic infections that usually involve the airways and/or intestine. In immunocompromised individuals, species A adenoviruses in general, and HAdV-31 in particular, cause life-threatening infections. By combining binding and infection experiments, we demonstrate that coagulation factor IX (FIX) efficiently enhances binding and infection by HAdV-18 and HAdV-31, but not by HAdV-12, in epithelial cells originating from the airways or intestine. This is markedly different from the mechanism for HAdV-5 and other human adenoviruses, which utilize coagulation factor X (FX) for infection of host cells. Surface plasmon resonance experiments revealed that the affinity of the HAdV-31 hexon-FIX interaction is higher than that of the HAdV-5 hexon-FX interaction and that the half-lives of these interactions are profoundly different. Moreover, both HAdV-31–FIX and HAdV-5–FX complexes bind to heparan sulfate-containing glycosaminoglycans (GAGs) on target cells, but binding studies utilizing cells expressing specific GAGs and GAG-cleaving enzymes revealed differences in GAG dependence and specificity between these two complexes. These findings add to our understanding of the intricate infection pathways used by human adenoviruses, and they may contribute to better design of HAdV-based vectors for gene and cancer therapy. Furthermore, the interaction between the HAdV-31 hexon and FIX may also serve as a target for antiviral treatment. PMID:21976659

  9. Borna disease virus-induced neuronal degeneration dependent on host genetic background and prevented by soluble factors

    PubMed Central

    Wu, Yuan-Ju; Schulz, Herbert; Lin, Chia-Ching; Saar, Kathrin; Patone, Giannino; Fischer, Heike; Hübner, Norbert; Heimrich, Bernd; Schwemmle, Martin

    2013-01-01

    Infection of newborn rats with Borne disease virus (BDV) results in selective degeneration of granule cell neurons of the dentate gyrus (DG). To study cellular countermechanisms that might prevent this pathology, we screened for rat strains resistant to this BDV-induced neuronal degeneration. To this end, we infected hippocampal slice cultures of different rat strains with BDV and analyzed for the preservation of the DG. Whereas infected cultures of five rat strains, including Lewis (LEW) rats, exhibited a disrupted DG cytoarchitecture, slices of three other rat strains, including Sprague–Dawley (SD), were unaffected. However, efficiency of viral replication was comparable in susceptible and resistant cultures. Moreover, these rat strain–dependent differences in vulnerability were replicated in vivo in neonatally infected LEW and SD rats. Intriguingly, conditioned media from uninfected cultures of both LEW and SD rats could prevent BDV-induced DG damage in infected LEW hippocampal cultures, whereas infection with BDV suppressed the availability of these factors from LEW but not in SD hippocampal cultures. To gain further insights into the genetic basis for this rat strain–dependent susceptibility, we analyzed DG granule cell survival in BDV-infected cultures of hippocampal neurons derived from the F1 and F2 offspring of the crossing of SD and LEW rats. Genome-wide association analysis revealed one resistance locus on chromosome (chr) 6q16 in SD rats and, surprisingly, a locus on chr3q21-23 that was associated with susceptibility. Thus, BDV-induced neuronal degeneration is dependent on the host genetic background and is prevented by soluble protective factors in the disease-resistant SD rat strain. PMID:23319640

  10. Viral and host factors induce macrophage activation and loss of Toll Like Receptor tolerance in chronic HCV infection

    PubMed Central

    Dolganiuc, Angela; Norkina, Oxana; Kodys, Karen; Catalano, Donna; Bakis, Gennadiy; Marshall, Christopher; Mandrekar, Pranoti; Szabo, Gyongyi

    2007-01-01

    Background&Aims Persistent inflammation contributes to progression of liver damage in chronic HCV (cHCV) infection. Repeated exposure to Toll like receptor (TLR) ligands results in tolerance, a protective mechanism aimed at limiting inflammation. Methods Monocytes/macrophages were repeatedly stimulated via pro-inflammatory cytokine-inducing TLRs and evaluated for activation markers. Results Unlike monocytes (Mo) of controls or patients with non-alcoholic steatohepatitis, the Mo of cHCV patients were hyper-responsive and failed to show homo- or hetero-tolerance to TLR ligands, manifested by elevated TNFα production. Serum levels of IFNγ, endotoxin (TLR4 ligand) and HCV core protein (TLR2 ligand) were elevated in cHCV patients suggesting potential mechanisms for in vivo monocyte pre-activation. Treatment of normal monocytes with IFNγ resulted in loss of tolerance to LPS or HCV core protein. Further, we found increased levels of MyD88-IRAK1 complexes and NFκB activity both in monocytes of cHCV patients and in normal monocytes that lost TLR tolerance after IFNγ+LPS pretreatment. In vitro differentiation of TLR tolerant cHCV monocytes into macrophages restored their capacity to exhibit TLR tolerance to LPS and HCV core protein and this could be reversed by administration of IFNγ. cHCV patients exhibited increased TNFα in the circulation and in the liver. In cHCV livers we found Kupffer cell/macrophage activation indicated by increased CD163 and CD33 expression. Conclusions We identified that host-derived factors (IFNγ and endotoxin) and viral factors (HCV core protein) act in tandem to induce and maintain monocyte/macrophage activation, thus favoring persistent inflammation in patients with cHCV infection. PMID:17916356

  11. Dendritic Cell-Lymphocyte Cross Talk Downregulates Host Restriction Factor SAMHD1 and Stimulates HIV-1 Replication in Dendritic Cells

    PubMed Central

    Biedma, Marina Elizabeth; Lederle, Alexandre; Peressin, Maryse; Lambotin, Mélanie; Proust, Alizé; Decoville, Thomas; Schmidt, Sylvie; Laumond, Géraldine

    2014-01-01

    ABSTRACT Human immunodeficiency virus type 1 (HIV-1) replication in dendritic cells (DCs) is restricted by SAMHD1. This factor is counteracted by the viral protein Vpx; Vpx is found in HIV-2 and simian immunodeficiency virus (SIV) from sooty mangabeys (SIVsm) or from macaques (SIVmac) but is absent from HIV-1. We previously observed that HIV-1 replication in immature DCs is stimulated by cocultivation with primary T and B lymphocytes, suggesting that HIV-1 restriction in DCs may be overcome under coculture conditions. Here, we aimed to decipher the mechanism of SAMHD1-mediated restriction in DC-lymphocyte coculture. We found that coculture with lymphocytes downregulated SAMHD1 expression and was associated with increased HIV-1 replication in DCs. Moreover, in infected DC-T lymphocyte cocultures, DCs acquired maturation status and secreted type 1 interferon (alpha interferon [IFN-α]). The blockade of DC-lymphocyte cross talk by anti-ICAM-1 antibody markedly inhibited the stimulation of HIV-1 replication and prevented the downregulation of SAMHD1 expression in cocultured DCs. These results demonstrate that, in contrast to purified DCs, cross talk with lymphocytes downregulates SAMHD1 expression in DCs, triggering HIV-1 replication and an antiviral immune response. Therefore, HIV-1 replication and immune sensing by DCs should be investigated in more physiologically relevant models of DC/lymphocyte coculture. IMPORTANCE SAMHD1 restricts HIV-1 replication in dendritic cells (DCs). Here, we demonstrate that, in a coculture model of DCs and lymphocytes mimicking early mucosal HIV-1 infection, stimulation of HIV-1 replication in DCs is associated with downregulation of SAMHD1 expression and activation of innate immune sensing by DCs. We propose that DC-lymphocyte cross talk occurring in vivo modulates host restriction factor SAMHD1, promoting HIV-1 replication in cellular reservoirs and stimulating immune sensing. PMID:24574390

  12. A critical role for the host mediator macrophage migration inhibitory factor in the pathogenesis of malarial anemia

    PubMed Central

    McDevitt, Michael A.; Xie, Jianlin; Shanmugasundaram, Ganapathy; Griffith, Jason; Liu, Aihua; McDonald, Courtney; Thuma, Philip; Gordeuk, Victor R.; Metz, Christine N.; Mitchell, Robert; Keefer, Jeffrey; David, John; Leng, Lin; Bucala, Richard

    2006-01-01

    The pathogenesis of malarial anemia is multifactorial, and the mechanisms responsible for its high mortality are poorly understood. Studies indicate that host mediators produced during malaria infection may suppress erythroid progenitor development (Miller, K.L., J.C. Schooley, K.L. Smith, B. Kullgren, L.J. Mahlmann, and P.H. Silverman. 1989. Exp. Hematol. 17:379–385; Yap, G.S., and M.M. Stevenson. 1991. Ann. NY Acad. Sci. 628:279–281). We describe an intrinsic role for macrophage migration inhibitory factor (MIF) in the development of the anemic complications and bone marrow suppression that are associated with malaria infection. At concentrations found in the circulation of malaria-infected patients, MIF suppressed erythropoietin-dependent erythroid colony formation. MIF synergized with tumor necrosis factor and γ interferon, which are known antagonists of hematopoiesis, even when these cytokines were present in subinhibitory concentrations. MIF inhibited erythroid differentiation and hemoglobin production, and it antagonized the pattern of mitogen-activated protein kinase phosphorylation that normally occurs during erythroid progenitor differentiation. Infection of MIF knockout mice with Plasmodium chabaudi resulted in less severe anemia, improved erythroid progenitor development, and increased survival compared with wild-type controls. We also found that human mononuclear cells carrying highly expressed MIF alleles produced more MIF when stimulated with the malarial product hemozoin compared with cells carrying low expression MIF alleles. These data suggest that polymorphisms at the MIF locus may influence the levels of MIF produced in the innate response to malaria infection and the likelihood of anemic complications. PMID:16636133

  13. Factors predicting response and graft-versus-host disease after donor lymphocyte infusions: a study on 593 infusions.

    PubMed

    Raiola, A M; Van Lint, M T; Valbonesi, M; Lamparelli, T; Gualandi, F; Occhini, D; Bregante, S; di Grazia, C; Dominietto, A; Soracco, M; Romagnani, C; Vassallo, F; Casini, M; Bruno, B; Frassoni, F; Bacigalupo, A

    2003-04-01

    In the present study, we analyze factors predicting graft-versus-host disease (GvHD) and response after donor lymphocyte infusions (DLI). A total of 100 patients received 593 DLI between June 1990 and December 2000 in a bulk dose (n=14) or in escalating dose infusions (n=86). Patients were analyzed after stratification for type of relapse: (1). molecular relapse (n=6), (2). cytogenetic relapse (n=20), (3). chronic phase of chronic myeloid leukemia (CML) or complete remission of other disease post chemotherapy (n=24), (4). CML in accelerated/blastic phase (n=14), (5). resistant disease not responding to chemotherapy (n=36). The proportion of responders to DLI in these five groups was 100, 90, 75, 36 and 0% (P<0.0001). Factors predicting response by multivariate analysis were type of relapse (P<0.0001), post-DLI GvHD (P=0.005), pancytopenia (P=0.008), and a diagnosis of CML (P=0.04). Acute GvHD (grades II-IV) occurred in 21 patients (21%), and correlated in multivariate analysis with pancytopenia and less than four DLI. Other predictors of GvHD were the number of CD3+cells/infusion and serum levels of gamma-glutamyl transferase (gammaGT). The actuarial probability of treatment-related mortality was 9% for HLA identical siblings and 44% for alternative donor transplants (P=0.006). Response to DLI is predicted by tumor burden and is associated with GvHD and pancytopenia. PMID:12692609

  14. SEASONAL ECOLOGY OF BEMISIA TABACI IN ARIZONA: LOW TEMPERATURE AND HOST PLANT EFFECTS ON FIELD POPULATIONS AND ASSOCIATED MORTALITY FACTORS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The current ongoing study has examined seasonality and mortality patterns of B. tabaci on different hosts during the year. Plots of six representative host plants (broccoli, cantaloupe, cotton, alfalfa, Lantana and various weeds) were established at the Yuma, Maricopa and Marana Agricultural Centers...

  15. The interplay of host genetic factors and Epstein-Barr virus in the development of nasopharyngeal carcinoma

    PubMed Central

    Lung, Maria Li; Cheung, Arthur Kwok Leung; Ko, Josephine Mun Yee; Lung, Hong Lok; Cheng, Yue; Dai, Wei

    2014-01-01

    The interplay between host cell genetics and Epstein-Barr virus (EBV) infection contributes to the development of nasopharyngeal carcinoma (NPC). Understanding the host genetic and epigenetic alterations and the influence of EBV on cell signaling and host gene regulation will aid in understanding the molecular pathogenesis of NPC and provide useful biomarkers and targets for diagnosis and therapy. In this review, we provide an update of the oncogenes and tumor suppressor genes associated with NPC, as well as genes associated with NPC risk including those involved in carcinogen detoxification and DNA repair. We also describe the importance of host genetics that govern the human leukocyte antigen (HLA) complex and immune responses, and we describe the impact of EBV infection on host cell signaling changes and epigenetic regulation of gene expression. High-power genomic sequencing approaches are needed to elucidate the genetic basis for inherited susceptibility to NPC and to identify the genes and pathways driving its molecular pathogenesis. PMID:25367335

  16. Aitchbone hanging and ageing period are additive factors influencing pork eating quality.

    PubMed

    Channon, H A; Taverner, M R; D'Souza, D N; Warner, R D

    2014-01-01

    The effects of abattoir, carcase weight (60 or 80 kg HCW), hanging method (Achilles or aitchbone) and ageing period (2 or 7 day post-slaughter) on eating quality attributes of pork were investigated in this 3×2×2×2 factorial study. A total of 144 Large White×Landrace female pigs were slaughtered at one of three abattoirs and sides hung from either the Achilles tendon or the aitchbone. After 24 h chilling, loin (M. longissimus thoracis et lumborum) and topside (M. semimembranosus) muscles were individually vacuum packaged and aged for 2 or 7 days post-slaughter. Consumers (n=852) evaluated eating quality. Neither abattoir nor carcase weight influenced tenderness, flavour or overall liking of pork. Improvements in tenderness, flavour and overall liking were found due to aitchbone hanging (P<0.001) and ageing (P<0.001) for 7 days compared with Achilles-hung carcases and pork aged for 2 days, respectively. This study demonstrated that aitchbone hanging and 7 day ageing can improve eating quality, but these effects were additive as the interaction term was not significant. PMID:24013699

  17. Electrical inhibition of lens epithelial cell proliferation: an additional factor in secondary cataract?

    PubMed Central

    Wang, Entong; Reid, Brian; Lois, Noemi; Forrester, John V.; McCaig, Colin D.; Zhao, Min

    2005-01-01

    Cataract is the most common cause of blindness but is at least curable by surgery. Unfortunately, many patients gradually develop the complication of posterior capsule opacification (PCO) or secondary cataract. This arises from stimulated cell growth within the lens capsule and can greatly impair vision. It is not fully understood why residual lens epithelial cell growth occurs after surgery. We propose and show that cataract surgery might remove an important inhibitory factor for lens cell growth, namely electric fields. The lens generates a unique pattern of electric currents constantly flowing out from the equator and entering the anterior and posterior poles. We show here that cutting and removing part of the anterior capsule as in cataract surgery significantly decreases the equatorial outward electric currents. Application of electric fields in culture inhibits proliferation of human lens epithelial cells. This inhibitory effect is likely to be mediated through a cell cycle control mechanism that decreases entry of cells into S phase from G1 phase by decreasing the G1-specific cell cycle protein cyclin E and increasing the cyclin-Cdk complex inhibitor p27kip1. Capsulorrhexis in vivo, which reduced endogenous lens electric fields, significantly increased LEC growth. This, together with our previous findings that electric fields have significant effects on the direction of lens cell migration, points to a controlling mechanism for the aberrant cell growth in posterior capsule opacification. A novel approach to control growth of lens epithelial cells using electric fields combined with other controlling mechanisms may be more effective in the prevention and treatment of this common complication of cataract surgery. PMID:15764648

  18. Ostertagia ostertagi macrophage migration inhibition factor is present at all developmental stages and may cross-regulate host functions through host receptor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Macrophage migration inhibition factor (MIF) of Ostertagia ostertagi, a parasitic nematode infecting the bovine abomasum, is characterized in the present study. Phylogenetic analysis indicates that there appears to be at least 3 OoMIFs encoded by distinct transcripts, including OoMIF1a, OoMIF1b, and...

  19. Postzygotic isolating factor in sympatric speciation in Rhagoletis flies: reduced response of hybrids to parental host-fruit odors.

    PubMed

    Linn, Charles E; Dambroski, Hattie R; Feder, Jeffrey L; Berlocher, Stewart H; Nojima, Satoshi; Roelofs, Wendell L

    2004-12-21

    Rhagoletis pomonella is a model for sympatric speciation (divergence without geographic isolation) by means of host-plant shifts. Many Rhagoletis species are known to use fruit odor as a key olfactory cue to distinguish among their respective host plants. Because Rhagoletis rendezvous on or near the unabscised fruit of their hosts to mate, behavioral preferences for fruit odor translate directly into premating reproductive isolation among flies. Here, we report that reciprocal F(1) hybrids between the apple and hawthorn host races of R. pomonella, as well as between the host races and an undescribed sibling species infesting Cornus florida (flowering dogwood) do not respond to host fruit volatiles in wind-tunnel assays at doses that elicit maximal directed flight in parental flies. The reduced ability of hybrids to orient to fruit volatiles could result from a conflict between neural pathways for preference and avoidance behaviors, and it suggests that hybrids might suffer a fitness disadvantage for finding fruit in nature. Therefore, host-specific mating may play a dual role as an important postzygotic as well as a premating reproductive barrier to isolate sympatric Rhagoletis flies. PMID:15591346

  20. Optimization of five environmental factors to increase beta-propeller phytase production in Pichia pastoris and impact on the physiological response of the host.

    PubMed

    Viader-Salvadó, José M; Castillo-Galván, Miguel; Fuentes-Garibay, José A; Iracheta-Cárdenas, María M; Guerrero-Olazarán, Martha

    2013-01-01

    Recently, we engineered Pichia pastoris Mut(s) strains to produce several beta-propeller phytases, one from Bacillus subtilis and the others designed by a structure-guided consensus approach. Furthermore, we demonstrated the ability of P. pastoris to produce and secrete these phytases in an active form in shake-flask cultures. In the present work, we used a design of experiments strategy (Simplex optimization method) to optimize five environmental factors that define the culture conditions in the induction step to increase beta-propeller phytase production in P. pastoris bioreactor cultures. With the optimization process, up to 347,682 U (82,814 U/L or 6.4 g/L culture medium) of phytase at 68 h of induction was achieved. In addition, the impact of the optimization process on the physiological response of the host was evaluated. The results indicate that the increase in extracellular phytase production through the optimization process was correlated with an increase in metabolic activity of P. pastoris, shown by an increase in oxygen demand and methanol consumption, that increase the specific growth rate. The increase in extracellular phytase production also occurred with a decrease in extracellular protease activity. Moreover, the optimized culture conditions increased the recombinant protein secretion by up to 88%, along with the extracellular phytase production efficiency per cell. PMID:24123973

  1. The chromosome localization and the HCF repeats of the human host cell factor gene (HCFC1) are conserved in the mouse homologue

    SciTech Connect

    Frattini, A.; Faranda, S.; Sacco, M.G.; Villa, A.; Vezzoni, P.

    1996-03-01

    The gene encoding the human host cell factor (HCFC1) has recently been cloned and mapped to Xq28. HCFC1 codes for a family of related polypeptides that apparently arise from posttranslational processing. Six extremely conserved 19-amino-acid (aa)-long motifs, unique to HCFC1 and located in the middle of the protein, could play a role in this processing or could be instrumental to the physiological role of the protein. Alternatively, these repeats could have arisen from recent duplications and may not have any specific function. To resolve this issue, we cloned the homologous region from the mouse Hcfc1 gene and demonstrated that the 19-aa motifs are extremely conserved in sequence, number, and genomic organization, while the {open_quotes}linker{close_quotes} region between the third and fourth repeat is not. This suggests an important function for these repeats. In addition, by RT-PCR analysis of human RNA and comparison to the human genomic sequence, an alternative transcript including a 44-aa in-frame insertion, driving from the 3{prime} nd of intron 18, was found. The significance of this alternative transcript is unknown, since it was not detectable in the mouse. The mouse Hcfc1 gene maps to a region syntenic to Xq28, and, as in human, is in close proximity to the Renin-binding protein gene, in a 100-kb region also including the L1cam and Vasopressin receptor type 2 genes. 8 refs., 2 figs.

  2. Myxoma virus M064 is a novel member of the poxvirus C7L superfamily of host range factors that controls the kinetics of myxomatosis in European rabbits.

    PubMed

    Liu, Jia; Wennier, Sonia; Moussatche, Nissin; Reinhard, Mary; Condit, Richard; McFadden, Grant

    2012-05-01

    The myxoma virus (MYXV) carries three tandem C7L-like host range genes (M062R, M063R, and M064R). However, despite the fact that the sequences of these three genes are similar, they possess very distinctive functions in vivo. The role of M064 in MYXV pathogenesis was investigated and compared to the roles of M062 and M063. We report that M064 is a virulence factor that contributes to MYXV pathogenesis but lacks the host range properties associated with M062 and M063. PMID:22379095

  3. Genome-Wide Small Interfering RNA Screens Reveal VAMP3 as a Novel Host Factor Required for Uukuniemi Virus Late Penetration

    PubMed Central

    Meier, Roger; Franceschini, Andrea; Horvath, Peter; Tetard, Marilou; Mancini, Roberta; von Mering, Christian; Helenius, Ari

    2014-01-01

    ABSTRACT The Bunyaviridae constitute a large family of enveloped animal viruses, many of which are important emerging pathogens. How bunyaviruses enter and infect mammalian cells remains largely uncharacterized. We used two genome-wide silencing screens with distinct small interfering RNA (siRNA) libraries to investigate host proteins required during infection of human cells by the bunyavirus Uukuniemi virus (UUKV), a late-penetrating virus. Sequence analysis of the libraries revealed that many siRNAs in the screens inhibited infection by silencing not only the intended targets but additional genes in a microRNA (miRNA)-like manner. That the 7-nucleotide seed regions in the siRNAs can cause a perturbation in infection was confirmed by using synthetic miRNAs (miRs). One of the miRs tested, miR-142-3p, was shown to interfere with the intracellular trafficking of incoming viruses by regulating the v-SNARE VAMP3, a strong hit shared by both siRNA screens. Inactivation of VAMP3 by the tetanus toxin led to a block in infection. Using fluorescence-based techniques in fixed and live cells, we found that the viruses enter VAMP3+ endosomal vesicles 5 min after internalization and that colocalization was maximal 15 min thereafter. At this time, LAMP1 was associated with the VAMP3+ virus-containing endosomes. In cells depleted of VAMP3, viruses were mainly trapped in LAMP1-negative compartments. Together, our results indicated that UUKV relies on VAMP3 for penetration, providing an indication of added complexity in the trafficking of viruses through the endocytic network. IMPORTANCE Bunyaviruses represent a growing threat to humans and livestock globally. Unfortunately, relatively little is known about these emerging pathogens. We report here the first human genome-wide siRNA screens for a bunyavirus. The screens resulted in the identification of 562 host cell factors with a potential role in cell entry and virus replication. To demonstrate the robustness of our approach, we

  4. Molecular Dissection of Mycobacterium tuberculosis Integration Host Factor Reveals Novel Insights into the Mode of DNA Binding and Nucleoid Compaction*

    PubMed Central

    Sharadamma, Narayanaswamy; Harshavardhana, Yadumurthy; Ravishankar, Apoorva; Anand, Praveen; Chandra, Nagasuma; Muniyappa, K.

    2014-01-01

    The annotated whole-genome sequence of Mycobacterium tuberculosis revealed that Rv1388 (Mtihf) is likely to encode for a putative 20-kDa integration host factor (mIHF). However, very little is known about the functional properties of mIHF or the organization of the mycobacterial nucleoid. Molecular modeling of the mIHF three-dimensional structure, based on the cocrystal structure of Streptomyces coelicolor IHF duplex DNA, a bona fide relative of mIHF, revealed the presence of Arg-170, Arg-171, and Arg-173, which might be involved in DNA binding, and a conserved proline (Pro-150) in the tight turn. The phenotypic sensitivity of Escherichia coli ΔihfA and ΔihfB strains to UV and methyl methanesulfonate could be complemented with the wild-type Mtihf but not its alleles bearing mutations in the DNA-binding residues. Protein-DNA interaction assays revealed that wild-type mIHF, but not its DNA-binding variants, binds with high affinity to fragments containing attB and attP sites and curved DNA. Strikingly, the functionally important amino acid residues of mIHF and the mechanism(s) underlying its binding to DNA, DNA bending, and site-specific recombination are fundamentally different from that of E. coli IHFαβ. Furthermore, we reveal novel insights into IHF-mediated DNA compaction depending on the placement of its preferred binding sites; mIHF promotes DNA compaction into nucleoid-like or higher order filamentous structures. We therefore propose that mIHF is a distinct member of a subfamily of proteins that serve as essential cofactors in site-specific recombination and nucleoid organization and that these findings represent a significant advance in our understanding of the role(s) of nucleoid-associated proteins. PMID:25324543

  5. A Novel, Broad-Spectrum Inhibitor of Enterovirus Replication That Targets Host Cell Factor Phosphatidylinositol 4-Kinase IIIβ

    PubMed Central

    van der Schaar, Hilde M.; Leyssen, Pieter; Thibaut, Hendrik J.; de Palma, Armando; van der Linden, Lonneke; Lanke, Kjerstin H. W.; Lacroix, Céline; Verbeken, Erik; Conrath, Katja; MacLeod, Angus M.; Mitchell, Dale R.; Palmer, Nicholas J.; van de Poël, Hervé; Andrews, Martin

    2013-01-01

    Despite their high clinical and socioeconomic impacts, there is currently no approved antiviral therapy for the prophylaxis or treatment of enterovirus infections. Here we report on a novel inhibitor of enterovirus replication, compound 1, 2-fluoro-4-(2-methyl-8-(3-(methylsulfonyl)benzylamino)imidazo[1,2-a]pyrazin-3-yl)phenol. This compound exhibited a broad spectrum of antiviral activity, as it inhibited all tested species of enteroviruses and rhinoviruses, with 50% effective concentrations ranging between 4 and 71 nM. After a lengthy resistance selection process, coxsackievirus mutants resistant to compound 1 were isolated that carried substitutions in their 3A protein. Remarkably, the same substitutions were recently shown to provide resistance to inhibitors of phosphatidylinositol 4-kinase IIIβ (PI4KIIIβ), a lipid kinase that is essential for enterovirus replication, suggesting that compound 1 may also target this host factor. Accordingly, compound 1 directly inhibited PI4KIIIβ in an in vitro kinase activity assay. Furthermore, the compound strongly reduced the PI 4-phosphate levels of the Golgi complex in cells. Rescue of coxsackievirus replication in the presence of compound 1 by a mutant PI4KIIIβ carrying a substitution in its ATP-binding pocket revealed that the compound directly binds the kinase at this site. Finally, we determined that an analogue of compound 1, 3-(3-fluoro-4-methoxyphenyl)-2-methyl-N-(pyridin-4-ylmethyl)imidazo[1,2-a]pyrazin-8-amine, is well tolerated in mice and has a dose-dependent protective activity in a coxsackievirus serotype B4-induced pancreatitis model. PMID:23896472

  6. The release of transforming growth factor-beta following haemorrhage: its role as a mediator of host immunosuppression.

    PubMed Central

    Ayala, A; Meldrum, D R; Perrin, M M; Chaudry, I H

    1993-01-01

    Haemorrhage in the absence of trauma is reported to induce a profound depression in cell-mediated immunity. Recent studies have drawn attention to the cytokine transforming growth factor-beta (TGF-beta) that, while important in wound healing, also has marked immunosuppressive effects. The aim of this study was to determine whether: (1) haemorrhage induces an increase in circulating TGF-beta and if this is associated with the loss of host immunoresponsiveness; and (2) administration of monoclonal antibody (mAb) to TGF-beta following haemorrhage ablates these changes. To determine this, C3H/HeN mice were bled to and maintained at a mean arterial pressure of 35 mmHg for 1 hr. This required removing approximately 50% of the circulating blood volume. Following this period of hypotension, the mice were adequately resuscitated. Blood samples obtained at 24 and 72 hr, but not at 2 hr, following haemorrhage showed a significant elevation in plasma TGF-beta levels when compared to shams. At 24 hr, the increase of TGF-beta in the plasma was associated with decreases in both concanavalin A (Con A)-induced splenocyte proliferation and splenic macrophage antigen presentation. Treating animals with neutralizing antibody (animals received 200 micrograms mAb against bovine TGF-beta 1,2,3/mouse intraarterially) not only reduced the levels of TGF-beta in the blood at 24 hr, but also restored splenocyte functions, such as Con A-induced proliferation, interleukin-2 (IL-2) release, and the capacity of splenic macrophages to present antigen. However, elevated levels of prostaglandin E2 (PGE2) seen in plasma during haemorrhage were only partially depressed by the antibody treatment. These results indicate that the release of TGF-beta contributes to the protracted (> or = 24 hr) suppression of cell-mediated immunity following haemorrhage. PMID:8406575

  7. An siRNA Screen Identifies the U2 snRNP Spliceosome as a Host Restriction Factor for Recombinant Adeno-associated Viruses

    PubMed Central

    Schreiber, Claire A.; Sakuma, Toshie; Izumiya, Yoshihiro; Holditch, Sara J.; Hickey, Raymond D.; Bressin, Robert K.; Basu, Upamanyu; Koide, Kazunori; Asokan, Aravind; Ikeda, Yasuhiro

    2015-01-01

    Adeno-associated viruses (AAV) have evolved to exploit the dynamic reorganization of host cell machinery during co-infection by adenoviruses and other helper viruses. In the absence of helper viruses, host factors such as the proteasome and DNA damage response machinery have been shown to effectively inhibit AAV transduction by restricting processes ranging from nuclear entry to second-strand DNA synthesis. To identify host factors that might affect other key steps in AAV infection, we screened an siRNA library that revealed several candidate genes including the PHD finger-like domain protein 5A (PHF5A), a U2 snRNP-associated protein. Disruption of PHF5A expression selectively enhanced transgene expression from AAV by increasing transcript levels and appears to influence a step after second-strand synthesis in a serotype and cell type-independent manner. Genetic disruption of U2 snRNP and associated proteins, such as SF3B1 and U2AF1, also increased expression from AAV vector, suggesting the critical role of U2 snRNP spliceosome complex in this host-mediated restriction. Notably, adenoviral co-infection and U2 snRNP inhibition appeared to target a common pathway in increasing expression from AAV vectors. Moreover, pharmacological inhibition of U2 snRNP by meayamycin B, a potent SF3B1 inhibitor, substantially enhanced AAV vector transduction of clinically relevant cell types. Further analysis suggested that U2 snRNP proteins suppress AAV vector transgene expression through direct recognition of intact AAV capsids. In summary, we identify U2 snRNP and associated splicing factors, which are known to be affected during adenoviral infection, as novel host restriction factors that effectively limit AAV transgene expression. Concurrently, we postulate that pharmacological/genetic manipulation of components of the spliceosomal machinery might enable more effective gene transfer modalities with recombinant AAV vectors. PMID:26244496

  8. Toward an Integrated Linkage Map of Common Bean. III. Mapping Genetic Factors Controlling Host-Bacteria Interactions

    PubMed Central

    Nodari, R. O.; Tsai, S. M.; Guzman, P.; Gilbertson, R. L.; Gepts, P.

    1993-01-01

    Restriction fragment length polymorphism (RFLP)-based genetic linkage maps allow us to dissect the genetic control of quantitative traits (QT) by locating individual quantitative trait loci (QTLs) on the linkage map and determining their type of gene action and the magnitude of their contribution to the phenotype of the QT. We have performed such an analysis for two traits in common bean, involving interactions between the plant host and bacteria, namely Rhizobium nodule number (NN) and resistance to common bacterial blight (CBB) caused by Xanthomonas campestris pv. phaseoli. Analyses were conducted in the progeny of a cross between BAT93 (fewer nodules; moderately resistant to CBB) and Jalo EEP558 (more nodules; susceptible to CBB). An RFLP-based linkage map for common bean based on 152 markers had previously been derived in the F(2) of this cross. Seventy F(2)-derived F(3) families were inoculated in separate greenhouse experiments with Rhizobium tropici strain UMR1899 or X. c. pv. phaseoli isolate isolate W18. Regression and interval mapping analyses were used to identify genomic regions involved in the genetic control of these traits. These two methods identified the same genomic regions for each trait, with a few exceptions. For each trait, at least four putative QTLs were identified, which accounted for approximately 50% and 75% of the phenotypic variation in NN and CBB resistance, respectively. A chromosome region on linkage group D7 carried factor(s) influencing both traits. In all other cases, the putative QTLs affecting NN and CBB were located in different linkage groups or in the same linkage group, but far apart (more than 50 cM). Both BAT93 and Jalo EEP558 contributed alleles associated with higher NN, whereas CBB resistance was always associated with BAT93 alleles. Further investigations are needed to determine whether the QTLs for NN and CBB on linkage group D7 represent linked genes or the same gene with pleiotropic effects. Identification of the

  9. A Novel Approach - The Propensity to Propagate (PTP) Method for Controlling for Host Factors in Studying the Transmission of Mycobacterium Tuberculosis

    PubMed Central

    Nebenzahl-Guimaraes, Hanna; Borgdorff, Martien W.; Murray, Megan B.; van Soolingen, Dick

    2014-01-01

    Rationale Understanding the genetic variations among Mycobacterium tuberculosis (MTB) strains with differential ability to transmit would be a major step forward in preventing transmission. Objectives To describe a method to extend conventional proxy measures of transmissibility by adjusting for patient-related factors, thus strengthening the causal association found with bacterial factors. Methods Clinical, demographic and molecular fingerprinting data were obtained during routine surveillance of verified MTB cases reported in the Netherlands between 1993 and 2011, and the phylogenetic lineages of the isolates were inferred. Odds ratios for host risk factors for clustering were used to obtain a measure of each patient's and cluster's propensity to propagate (CPP). Mean and median cluster sizes across different categories of CPP were compared amongst four different phylogenetic lineages. Results Both mean and median cluster size grew with increasing CPP category. On average, CPP values from Euro-American lineage strains were higher than Beijing and EAI strains. There were no significant differences between the mean and median cluster sizes among the four phylogenetic lineages within each CPP category. Conclusions Our finding that the distribution of CPP scores was unequal across four different phylogenetic lineages supports the notion that host-related factors should be controlled for to attain comparability in measuring the different phylogenetic lineages' ability to propagate. Although Euro-American strains were more likely to be in clusters in an unadjusted analysis, no significant differences among the four lineages persisted after we controlled for host factors. PMID:24849817

  10. Tissue-specific factors additively increase the probability of the all-or-none formation of a hypersensitive site.

    PubMed Central

    Boyes, J; Felsenfeld, G

    1996-01-01

    DNase I-hypersensitive sites lack a canonical nucleosome and have binding sites for various transcription factors. To understand how the hypersensitivity is generated and maintained, we studied the chicken erythroid-specific beta(A)/epsilon globin gene enhancer, a region where both tissue-specific and ubiquitous transcription factors can bind. Constructions containing mutations of this enhancer were stably introduced into a chicken erythroid cell line. We found that the hypersensitivity was determined primarily by the erythroid factors and that their binding additively increased the accessibility. The fraction of accessible sites in clonal cell lines was quantitated using restriction endonucleases; these data implied that the formation of each hypersensitive site was an all-or-none phenomenon. Use of DNase I and micrococcal nuclease probes further indicated that the size of the hypersensitive site was influenced by the binding of transcription factors which then determined the length of the nucleosome-free gap. Our data are consistent with a model in which hypersensitive sites are generated stochastically: mutations that reduce the number of bound factors reduce the probability that these factors will prevail over a nucleosome; thus, the fraction of sites in the population that are accessible is also diminished. Images PMID:8665857

  11. Identification of Cholesterol 25-Hydroxylase as a Novel Host Restriction Factor and a Part of the Primary Innate Immune Responses against Hepatitis C Virus Infection

    PubMed Central

    Xiang, Yu; Tang, Jing-Jie; Tao, Wanyin; Cao, Xuezhi; Song, Bao-Liang

    2015-01-01

    ABSTRACT Hepatitis C virus (HCV), a single-stranded positive-sense RNA virus of the Flaviviridae family, causes chronic liver diseases, including hepatitis, cirrhosis, and cancer. HCV infection is critically dependent on host lipid metabolism, which contributes to all stages of the viral life cycle, including virus entry, replication, assembly, and release. 25-Hydroxycholesterol (25HC) plays a critical role in regulating lipid metabolism, modulating immune responses, and suppressing viral pathogens. In this study, we showed that 25HC and its synthesizing enzyme cholesterol 25-hydroxylase (CH25H) efficiently inhibit HCV infection at a postentry stage. CH25H inhibits HCV infection by suppressing the maturation of SREBPs, critical transcription factors for host lipid biosynthesis. Interestingly, CH25H is upregulated upon poly(I·C) treatment or HCV infection in hepatocytes, which triggers type I and III interferon responses, suggesting that the CH25H induction constitutes a part of host innate immune response. To our surprise, in contrast to studies in mice, CH25H is not induced by interferons in human cells and knockdown of STAT-1 has no effect on the induction of CH25H, suggesting CH25H is not an interferon-stimulated gene in humans but rather represents a primary and direct host response to viral infection. Finally, knockdown of CH25H in human hepatocytes significantly increases HCV infection. In summary, our results demonstrate that CH25H constitutes a primary innate response against HCV infection through regulating host lipid metabolism. Manipulation of CH25H expression and function should provide a new strategy for anti-HCV therapeutics. IMPORTANCE Recent studies have expanded the critical roles of oxysterols in regulating immune response and antagonizing viral pathogens. Here, we showed that one of the oxysterols, 25HC and its synthesizing enzyme CH25H efficiently inhibit HCV infection at a postentry stage via suppressing the maturation of transcription factor

  12. Disentangling the relative importance of host tree community, abiotic environment and spatial factors on ectomycorrhizal fungal assemblages along an elevation gradient.

    PubMed

    Matsuoka, Shunsuke; Mori, Akira S; Kawaguchi, Eri; Hobara, Satoru; Osono, Takashi

    2016-05-01

    Recent studies have shown that changes in community compositions of ectomycorrhizal (ECM) fungi along elevation gradients are mainly affected by changes in host tree communities and/or in abiotic environments. However, few studies have taken the effects of processes related to fungal dispersal (i.e. spatial processes) into account and distinguished the effects of host community, abiotic environment and spatial processes on community composition along elevation gradients. This has left unclear the relative importance of these factors in structuring the ECM community assemblages. To address this, we investigated the community composition of ECM fungi along an elevation gradient in northern Japan with 454 meta-barcoding. We found that the community composition of ECM fungi changed along the elevation and that all three factors jointly affected the compositional changes. We separated the magnitude of importance of the three factors in structuring ECM fungal communities and found that most of the spatial variation in ECM fungal community was explained by host communities and abiotic environments. Our results suggest that while biotic and/or abiotic environments can be important factors in determining the ECM fungal community composition along an elevation gradient, spatial processes may also be a primary determinant. PMID:26917782

  13. The wheat ethylene response factor transcription factor pathogen-induced ERF1 mediates host responses to both the necrotrophic pathogen Rhizoctonia cerealis and freezing stresses.

    PubMed

    Zhu, Xiuliang; Qi, Lin; Liu, Xin; Cai, Shibin; Xu, Huijun; Huang, Rongfeng; Li, Jiarui; Wei, Xuening; Zhang, Zengyan

    2014-03-01

    Sharp eyespot disease (primarily caused by the pathogen Rhizoctonia cerealis) and freezing stress are important yield limitations for the production of wheat (Triticum aestivum). Here, we report new insights into the function and underlying mechanisms of an ethylene response factor (ERF) in wheat, Pathogen-Induced ERF1 (TaPIE1), in host responses to R. cerealis and freezing stresses. TaPIE1-overexpressing transgenic wheat exhibited significantly enhanced resistance to both R. cerealis and freezing stresses, whereas TaPIE1-underexpressing wheat plants were more susceptible to both stresses relative to control plants. Following both stress treatments, electrolyte leakage and hydrogen peroxide content were significantly reduced, and both proline and soluble sugar contents were elevated in TaPIE1-overexpressing wheat, whereas these physiological traits in TaPIE1-underexpressing wheat exhibited the opposite trend. Microarray and quantitative reverse transcription-polymerase chain reaction analyses of TaPIE1-overexpressing and -underexpressing wheat plants indicated that TaPIE1 activated a subset of defense- and stress-related genes. Assays of DNA binding by electrophoretic mobility shift and transient expression in tobacco (Nicotiana tabacum) showed that the GCC boxes in the promoters of TaPIE1-activated genes were essential for transactivation by TaPIE1. The transactivation activity of TaPIE1 and the expression of TaPIE1-activated defense- and stress-related genes were significantly elevated following R. cerealis, freezing, and exogenous ethylene treatments. TaPIE1-mediated responses to R. cerealis and freezing were positively modulated by ethylene biosynthesis. These data suggest that TaPIE1 positively regulates the defense responses to R. cerealis and freezing stresses by activating defense- and stress-related genes downstream of the ethylene signaling pathway and by modulating related physiological traits in wheat. PMID:24424323

  14. New insights into the transition pathway from nonspecific to specific complex of DNA with Escherichia coli integration host factor.

    PubMed

    Vivas, Paula; Kuznetsov, Serguei V; Ansari, Anjum

    2008-05-15

    To elucidate the nature of the transition-state ensemble along the reaction pathway from a nonspecific protein-DNA complex to the specific complex, we have carried out measurements of DNA bending/unbending dynamics on a cognate DNA substrate in complex with integration host factor (IHF), an architectural protein from E. coli that bends its cognate site by approximately 180 degrees . We use a laser temperature jump to perturb the IHF-DNA complex and monitor the relaxation kinetics with time-resolved FRET measurements on DNA substrates end-labeled with a FRET pair. Previously, we showed that spontaneous bending/kinking of DNA, from thermal disruption of base-pairing/-stacking interactions, may be the rate-limiting step in the formation of the specific complex (Kuznetsov, S. V.; Sugimura, S.; Vivas, P.; Crothers, D. M.; Ansari, A. Proc. Natl. Acad. Sci. USA 2006, 103, 18515). Here, we probe the effect of varying [KCl], which affects the stability of the complex, on this rate-limiting step. We find that below approximately 250 mM KCl, the observed relaxation kinetics are from the unimolecular bending/unbending of DNA, and the relaxation rate kr is independent of [KCl]. Above approximately 300 mM KCl, dissociation of the IHF-DNA complex becomes significant, and the observed relaxation process includes contributions from the association/dissociation step, with kr decreasing with increasing [KCl]. The DNA bending step occurs with a positive activation enthalpy, despite the large negative enthalpy change reported for the specific IHF-DNA complex (Holbrook, J. A.; Tsodikov, O. V.; Saecker, R. M.; Record, M. T., Jr. J. Mol. Biol. 2001, 310, 379). Our conclusion from these studies is that in the uphill climb to the transition state, the DNA is kinked, but with no release of ions, as indicated by the salt-independent behavior of k(r) at low [KCl]. Any release of ions in the unimolecular process, together with conformational changes in the protein-DNA complex that facilitate

  15. Host Factors That Interact with the Pestivirus N-Terminal Protease, Npro, Are Components of the Ribonucleoprotein Complex

    PubMed Central

    Jefferson, Matthew; Donaszi-Ivanov, Andras; Pollen, Sean; Dalmay, Tamas; Saalbach, Gerhard

    2014-01-01

    ABSTRACT The viral N-terminal protease Npro of pestiviruses counteracts cellular antiviral defenses through inhibition of IRF3. Here we used mass spectrometry to identify a new role for Npro through its interaction with over 55 associated proteins, mainly ribosomal proteins and ribonucleoproteins, including RNA helicase A (DHX9), Y-box binding protein (YBX1), DDX3, DDX5, eIF3, IGF2BP1, multiple myeloma tumor protein 2, interleukin enhancer binding factor 3 (IEBP3), guanine nucleotide binding protein 3, and polyadenylate-binding protein 1 (PABP-1). These are components of the translation machinery, ribonucleoprotein particles (RNPs), and stress granules. Significantly, we found that stress granule formation was inhibited in MDBK cells infected with a noncytopathic bovine viral diarrhea virus (BVDV) strain, Kyle. However, ribonucleoproteins binding to Npro did not inhibit these proteins from aggregating into stress granules. Npro interacted with YBX1 though its TRASH domain, since the mutant C112R protein with an inactive TRASH domain no longer redistributed to stress granules. Interestingly, RNA helicase A and La autoantigen relocated from a nuclear location to form cytoplasmic granules with Npro. To address a proviral role for Npro in RNP granules, we investigated whether Npro affected RNA interference (RNAi), since interacting proteins are involved in RISC function during RNA silencing. Using glyceraldehyde-3-phosphate dehydrogenase (GAPDH) silencing with small interfering RNAs (siRNAs) followed by Northern blotting of GAPDH, expression of Npro had no effect on RNAi silencing activity, contrasting with other viral suppressors of interferon. We propose that Npro is involved with virus RNA translation in the cytoplasm for virus particle production, and when translation is inhibited following stress, it redistributes to the replication complex. IMPORTANCE Although the pestivirus N-terminal protease, Npro, has been shown to have an important role in degrading IRF3 to

  16. Trypanosome infection in dromedary camels in Eastern Ethiopia: Prevalence, relative performance of diagnostic tools and host related risk factors.

    PubMed

    Fikru, Regassa; Andualem, Yimer; Getachew, Terefe; Menten, Joris; Hasker, Epco; Merga, Bekana; Goddeeris, Bruno Maria; Büscher, Philippe

    2015-07-30

    A cross-sectional study was conducted in Chifra and Dewe districts of Afar region, Eastern Ethiopia, to determine the prevalence, agreement between diagnostic tests and host related risk factors of trypanosome infection in camel. An overall prevalence of 2%, 24.1%, 21.3%, 9.5% and 7.8% was recorded with respectively Giemsa stained thin blood smear, CATT/T. evansi, RoTat1.2 PCR, 18S PCR and ITS-1PCR in a cohort of 399 animals. Only one T. vivax infection was confirmed by TvPRAC PCR indicating T. evansi as the predominant species affecting camels in the study area. No single animal was positive when tested with T. evansi type B specific EVAB PCR. There was slight agreement between the CATT/T. evansi and the molecular tests. Among the PCR methods, RoTat 1.2 PCR yielded a significantly higher positivity rate compared to 18S PCR and ITS-1 PCR. There was no significant difference in the positivity rate observed in each gender of camels (p>0.05). The positivity rate was significantly higher in camels with poor body condition and in older animals when tested using the CATT/T.evansi or RoTat 1.2 PCR (p>0.05). Camels that tested positive with all tests had significantly lower PCV's (p<0.05). This study provides further evidence that T. evansi is endemic in the Afar region of Ethiopia. The latent class analysis indicated an estimate overall prevalence of 19% (95% CI: 13-28). Moreover, the model indicated low sensitivity of CATT/T. evansi (43%) and the PCR tests (39-53%) but higher specificity of the PCR tests (86-99%) and low specificity of CATT/T. evansi (80%). This study suggests that improved sensitivity and reliability of the tests would help diagnosis of trypanosomosis. Further studies are required to determine the prevalence of clinical disease and losses due to trypanosomosis. PMID:26071981

  17. Global Genetic Differentiation in a Cosmopolitan Pest of Stored Beans: Effects of Geography, Host-Plant Usage and Anthropogenic Factors

    PubMed Central

    Tuda, Midori; Kagoshima, Kumiko; Toquenaga, Yukihiko; Arnqvist, Göran

    2014-01-01

    Genetic differentiation can be promoted allopatrically by geographic isolation of populations due to limited dispersal ability and diversification over time or sympatrically through, for example, host-race formation. In crop pests, the trading of crops across the world can lead to intermixing of genetically distinct pest populations. However, our understanding of the importance of allopatric and sympatric genetic differentiation in the face of anthropogenic genetic intermixing is limited. Here, we examined global sequence variation in two mitochondrial and one nuclear genes in the seed beetle Callosobruchus maculatus that uses different legumes as hosts. We analyzed 180 samples from 42 populations of this stored bean pest from tropical and subtropical continents and archipelagos: Africa, the Middle East, South and Southeast Asia, Oceania and South America. For the mitochondrial genes, there was weak but significant genetic differentiation across continents/archipelagos. Further, we found pronounced differentiation among subregions within continents/archipelagos both globally and within Africa but not within Asia. We suggest that multiple introductions into Asia and subsequent intermixing within Asia have generated this pattern. The isolation by distance hypothesis was supported globally (with or without continents controlled) but not when host species was restricted to cowpeas Vigna unguiculata, the ancestral host of C. maculatus. We also document significant among-host differentiation both globally and within Asia, but not within Africa. We failed to reject a scenario of a constant population size in the recent past combined with selective neutrality for the mitochondrial genes. We conclude that mitochondrial DNA differentiation is primarily due to geographic isolation within Africa and to multiple invasions by different alleles, followed by host shifts, within Asia. The weak inter-continental differentiation is most likely due to frequent inter-continental gene

  18. Global genetic differentiation in a cosmopolitan pest of stored beans: effects of geography, host-plant usage and anthropogenic factors.

    PubMed

    Tuda, Midori; Kagoshima, Kumiko; Toquenaga, Yukihiko; Arnqvist, Göran

    2014-01-01

    Genetic differentiation can be promoted allopatrically by geographic isolation of populations due to limited dispersal ability and diversification over time or sympatrically through, for example, host-race formation. In crop pests, the trading of crops across the world can lead to intermixing of genetically distinct pest populations. However, our understanding of the importance of allopatric and sympatric genetic differentiation in the face of anthropogenic genetic intermixing is limited. Here, we examined global sequence variation in two mitochondrial and one nuclear genes in the seed beetle Callosobruchus maculatus that uses different legumes as hosts. We analyzed 180 samples from 42 populations of this stored bean pest from tropical and subtropical continents and archipelagos: Africa, the Middle East, South and Southeast Asia, Oceania and South America. For the mitochondrial genes, there was weak but significant genetic differentiation across continents/archipelagos. Further, we found pronounced differentiation among subregions within continents/archipelagos both globally and within Africa but not within Asia. We suggest that multiple introductions into Asia and subsequent intermixing within Asia have generated this pattern. The isolation by distance hypothesis was supported globally (with or without continents controlled) but not when host species was restricted to cowpeas Vigna unguiculata, the ancestral host of C. maculatus. We also document significant among-host differentiation both globally and within Asia, but not within Africa. We failed to reject a scenario of a constant population size in the recent past combined with selective neutrality for the mitochondrial genes. We conclude that mitochondrial DNA differentiation is primarily due to geographic isolation within Africa and to multiple invasions by different alleles, followed by host shifts, within Asia. The weak inter-continental differentiation is most likely due to frequent inter-continental gene

  19. Host Factors Influencing the Retrohoming Pathway of Group II Intron RmInt1, Which Has an Intron-Encoded Protein Naturally Devoid of Endonuclease Activity.

    PubMed

    Nisa-Martínez, Rafael; Molina-Sánchez, María Dolores; Toro, Nicolás

    2016-01-01

    Bacterial group II introns are self-splicing catalytic RNAs and mobile retroelements that have an open reading frame encoding an intron-encoded protein (IEP) with reverse transcriptase (RT) and RNA splicing or maturase activity. Some IEPs carry a DNA endonuclease (En) domain, which is required to cleave the bottom strand downstream from the intron-insertion site for target DNA-primed reverse transcription (TPRT) of the inserted intron RNA. Host factors complete the insertion of the intron. By contrast, the major retrohoming pathway of introns with IEPs naturally lacking endonuclease activity, like the Sinorhizobium meliloti intron RmInt1, is thought to involve insertion of the intron RNA into the template for lagging strand DNA synthesis ahead of the replication fork, with possible use of the nascent strand to prime reverse transcription of the intron RNA. The host factors influencing the retrohoming pathway of such introns have not yet been described. Here, we identify key candidates likely to be involved in early and late steps of RmInt1 retrohoming. Some of these host factors are common to En+ group II intron retrohoming, but some have different functions. Our results also suggest that the retrohoming process of RmInt1 may be less dependent on the intracellular free Mg2+ concentration than those of other group II introns. PMID:27588750

  20. Biotic mortality factors affecting emerald ash borer (Agrilus planipennis) are highly dependent on life stage and host tree crown condition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Emerald ash borer (EAB), Agrilus planipennis, is a serious invasive forest pest in North America responsible for killing tens to hundreds of millions of ash trees since it was accidentally introduced in the 1990’s. Although host plant resistance and natural enemies are known to be important sources ...

  1. The effects of genotype and infant weight on adult plasma levels of fibrinogen, factor VII, and LDL cholesterol are additive.

    PubMed Central

    Henry, J A; Bolla, M; Osmond, C; Fall, C; Barker, D J; Humphries, S E

    1997-01-01

    High circulating levels of cholesterol, particularly low density lipoprotein (LDL) cholesterol and the clotting factors fibrinogen and factor VII, are associated with increased risk of myocardial infarction. Variations in the plasma levels of these factors are determined in part by polymorphisms in the genes concerned and also by weight at 1 year (infant weight). We have looked at the possibility of interactions between these genetic factors and infant weight in a sample of 290 men and 192 women from Hertfordshire using the beta-fibrinogen G/A-455, factor VII R353Q, and ApoE polymorphisms. The rare allele frequencies of the three polymorphisms were 0.19 for beta-fibrinogen, 0.10 for factor VII, and 0.07 and 0.13 for the 2 and 4 alleles of ApoE, and these frequencies were not different in subjects of different infant weight. In this sample, the polymorphisms showed the expected effects on plasma levels of fibrinogen, factor VII, and LDL cholesterol. The A-455 allele was associated with higher fibrinogen levels but the effect was only statistically significant in women (p = 0.003). The R353 allele was associated with higher factor VII activity in both men and women (p < 0.0001 for both). The ApoE2 allele was associated with lower levels of LDL cholesterol (p = 0.03 in men, p = 0.006 in women), while the ApoE4 allele was associated with higher levels (p < 0.001 in men, not significant in women). In this sample of men and women the effect of low infant weight was only associated with significant effects on fibrinogen and LDL cholesterol in the group of men (p = 0.005 and p = 0.008 respectively). Compared with the E3E3 subjects, the LDL lowering effect of the E2 allele and the raising effect of the E4 allele was greater in those with low infant weight compared with those with high infant weight (low v high infant weight for E2: 12.7% v 9.4%; for E4 12.7% v 8.5%). Although in this sample the interactive effect did not reach statistical significance, the additive effect

  2. Loss in CD4 T-cell responses to multiple epitopes in influenza due to expression of one additional MHC class II molecule in the host

    PubMed Central

    Nayak, Jennifer L; Sant, Andrea J

    2012-01-01

    An understanding of factors controlling CD4 T-cell immunodominance is needed to pursue CD4 T-cell epitope-driven vaccine design, yet our understanding of this in humans is limited by the complexity of potential MHC class II molecule expression. In the studies described here, we took advantage of genetically restricted, well-defined mouse strains to better understand the effect of increasing MHC class II molecule diversity on the CD4 T-cell repertoire and the resulting anti-influenza immunodominance hierarchy. Interferon-γ ELISPOT assays were implemented to directly quantify CD4 T-cell responses to I-Ab and I-As restricted peptide epitopes following primary influenza virus infection in parental and F1 hybrid strains. We found striking and asymmetric declines in the magnitude of many peptide-specific responses in F1 animals. These declines could not be accounted for by the lower surface density of MHC class II on the cell or by antigen-presenting cells failing to stimulate T cells with lower avidity T-cell receptors. Given the large diversity of MHC class II expressed in humans, these findings have important implications for the rational design of peptide-based vaccines that are based on the premise that CD4 T-cell epitope specificity can be predicted by a simple cataloguing of an individual’s MHC class II genotype. PMID:22747522

  3. Genetics, experience, and host-plant preference in Eurosta solidaginis: implications for host shifts and speciation.

    PubMed

    Craig, T P; Horner, J D; Itami, J K

    2001-04-01

    Host-associated mating is crucial in maintaining the partial reproductive isolation between the host races of Eurosta solidaginis (Diptera: Tephritidae), a fly that forms galls on Solidago altissima and S. gigantea. (We refer to flies reared from S. gigantea as gigantea flies and those reared from S. altissima as altissima flies.) We measured the host preference of males and females of both host races, F1 hybrids between the host races, F2, and backcrosses to both host races. Male and female altissima flies and female gigantea flies had high host fidelity, whereas male gigantea flies had low host fidelity. This result suggests that there may be gene flow between the host races due to nonassortative mating that occurs when male gigantea mate with altissima females on S. altissima. This indicates assortative-mating mechanisms in addition to host-associated mating are required to produce the partial reproductive isolation between the host races that has been observed. Nongenetic factors had no influence on host preference. Larval conditioning did not influence host preference: reciprocal F1 hybrids reared in S. altissima and S. gigantea both preferred S. gigantea. Adult experience had no impact on host preference: females preferred their natal host plant regardless of which host they encountered first as an adult. The hypothesis that maternal effects influence preferences was rejected because male and female flies did not show a consistent preference for the host plant of their mother. We also found no evidence that preference was a sex-linked trait because F1 and backcrosses to the host races with different combinations of X chromosomes from the two host races preferred S. gigantea. Our results indicate that host preference is not determined by a large number of genes because preference of hybrids did not correspond to the proportion of the genome derived from each host race. The strength of the ovipuncture preference for S. gigantea by gigantea females, the females

  4. Invasion biology in non-free-living species: interactions between abiotic (climatic) and biotic (host availability) factors in geographical space in crayfish commensals (Ostracoda, Entocytheridae)

    PubMed Central

    Mestre, Alexandre; Aguilar-Alberola, Josep A; Baldry, David; Balkis, Husamettin; Ellis, Adam; Gil-Delgado, Jose A; Grabow, Karsten; Klobučar, Göran; Kouba, Antonín; Maguire, Ivana; Martens, Andreas; Mülayim, Ayşegül; Rueda, Juan; Scharf, Burkhard; Soes, Menno; S Monrós, Juan; Mesquita-Joanes, Francesc

    2013-01-01

    In invasion processes, both abiotic and biotic factors are considered essential, but the latter are usually disregarded when modeling the potential spread of exotic species. In the framework of set theory, interactions between biotic (B), abiotic (A), and movement-related (M) factors in the geographical space can be hypothesized with BAM diagrams and tested using ecological niche models (ENMs) to estimate A and B areas. The main aim of our survey was to evaluate the interactions between abiotic (climatic) and biotic (host availability) factors in geographical space for exotic symbionts (i.e., non-free-living species), using ENM techniques combined with a BAM framework and using exotic Entocytheridae (Ostracoda) found in Europe as model organisms. We carried out an extensive survey to evaluate the distribution of entocytherids hosted by crayfish in Europe by checking 94 European localities and 12 crayfish species. Both exotic entocytherid species found, Ankylocythere sinuosa and Uncinocythere occidentalis, were widely distributed in W Europe living on the exotic crayfish species Procambarus clarkii and Pacifastacus leniusculus, respectively. No entocytherids were observed in the remaining crayfish species. The suitable area for A. sinuosa was mainly restricted by its own limitations to minimum temperatures in W and N Europe and precipitation seasonality in circum-Mediterranean areas. Uncinocythere occidentalis was mostly restricted by host availability in circum-Mediterranean regions due to limitations of P. leniusculus to higher precipitation seasonality and maximum temperatures. The combination of ENMs with set theory allows studying the invasive biology of symbionts and provides clues about biogeographic barriers due to abiotic or biotic factors limiting the expansion of the symbiont in different regions of the invasive range. The relative importance of abiotic and biotic factors on geographical space can then be assessed and applied in conservation plans. This

  5. Hosts and parasites as aliens.

    PubMed

    Taraschewski, H

    2006-06-01

    Over the past decades, various free-living animals (hosts) and their parasites have invaded recipient areas in which they had not previously occurred, thus gaining the status of aliens or exotics. In general this happened to a low extent for hundreds of years. With variable frequency, invasions have been followed by the dispersal and establishment of non-indigenous species, whether host or parasite. In the literature thus far, colonizations by both hosts and parasites have not been treated and reviewed together, although both are usually interwoven in various ways. As to those factors permitting invasive success and colonization strength, various hypotheses have been put forward depending on the scientific background of respective authors and on the conspicuousness of certain invasions. Researchers who have tried to analyse characteristic developmental patterns, the speed of dispersal or the degree of genetic divergence in populations of alien species have come to different conclusions. Among parasitologists, the applied aspects of parasite invasions, such as the negative effects on economically important hosts, have long been at the centre of interest. In this contribution, invasions by hosts as well as parasites are considered comparatively, revealing many similarities and a few differences. Two helminths, the liver fluke, Fasciola hepatica, of cattle and sheep and the swimbladder nematode, Anguillicola crassus, of eels are shown to be useful as model parasites for the study of animal invasions and environmental global change. Introductions of F. hepatica have been associated with imports of cattle or other grazing animals. In various target areas, susceptible lymnaeid snails serving as intermediate hosts were either naturally present and/or were introduced from the donor continent of the parasite (Europe) and/or from other regions which were not within the original range of the parasite, partly reflecting progressive stages of a global biota change. In several

  6. Global Repression of Host-Associated Genes of the Lyme Disease Spirochete through Post-Transcriptional Modulation of the Alternative Sigma Factor RpoS

    PubMed Central

    Dulebohn, Daniel P.; Hayes, Beth M.; Rosa, Patricia A.

    2014-01-01

    Borrelia burgdorferi, the agent of Lyme disease, is a vector-borne pathogen that transits between Ixodes ticks and vertebrate hosts. During the natural infectious cycle, spirochetes must globally adjust their transcriptome to survive in these dissimilar environments. One way B. burgdorferi accomplishes this is through the use of alternative sigma factors to direct transcription of specific genes. RpoS, one of only three sigma factors in B. burgdorferi, controls expression of genes required during tick-transmission and infection of the mammalian host. How spirochetes switch between different sigma factors during the infectious cycle has remained elusive. Here we establish a role for a novel protein, BBD18, in the regulation of the virulence-associated sigma factor RpoS. Constitutive expression of BBD18 repressed transcription of RpoS-dependent genes to levels equivalent to those observed in an rpoS mutant. Consistent with the global loss of RpoS-dependent transcripts, we were unable to detect RpoS protein. However, constitutive expression of BBD18 did not diminish the amount of rpoS transcript, indicating post-transcriptional regulation of RpoS by BBD18. Interestingly, BBD18-mediated repression of RpoS is independent of both the rpoS promoter and the 5’ untranslated region, suggesting a mechanism of protein destabilization rather than translational control. We propose that BBD18 is a novel regulator of RpoS and its activity likely represents a first step in the transition from an RpoS-ON to an RpoS-OFF state, when spirochetes transition from the host to the tick vector. PMID:24671196

  7. Lentiviral hepatitis B pseudotype entry requires sodium taurocholate co-transporting polypeptide and additional hepatocyte-specific factors.

    PubMed

    Meredith, L W; Hu, K; Cheng, X; Howard, C R; Baumert, T F; Balfe, P; van de Graaf, K F; Protzer, U; McKeating, J A

    2016-01-01

    Hepatitis B virus (HBV) is one of the world's major unconquered infections, resulting in progressive liver disease, and current treatments rarely cure infection. A limitation to discovering new therapies is our limited knowledge of HBV entry and dissemination pathways that hinders the development of in vitro culture systems. To address this gap in our understanding we optimized the genesis of infectious lentiviral pseudoparticles (HBVpps). The recent discovery that the bile salt transporter sodium taurocholate co-transporting polypeptide (NTCP) acts as a receptor for HBV enabled us to assess the receptor dependency of HBVpp infection. HBVpps preferentially infect hepatoma cells expressing NTCP, whereas other non-liver cells engineered to express NTCP do not support infection, suggesting that additional hepatocyte-specific factors are required for HBVpp internalization. These results highlight the value of the HBVpp system to dissect the pathways of HBV entry and dissemination. PMID:26474824

  8. Insulin receptor isoform A and insulin-like growth factor II as additional treatment targets in human osteosarcoma.

    PubMed

    Avnet, Sofia; Sciacca, Laura; Salerno, Manuela; Gancitano, Giovanni; Cassarino, Maria Francesca; Longhi, Alessandra; Zakikhani, Mahvash; Carboni, Joan M; Gottardis, Marco; Giunti, Armando; Pollak, Michael; Vigneri, Riccardo; Baldini, Nicola

    2009-03-15

    Despite the frequent presence of an insulin-like growth factor I receptor (IGFIR)-mediated autocrine loop in osteosarcoma (OS), interfering with this target was only moderately effective in preclinical studies. Here, we considered other members of the IGF system that might be involved in the molecular pathology of OS. We found that, among 45 patients with OS, IGF-I and IGFBP-3 serum levels were significantly lower, and IGF-II serum levels significantly higher, than healthy controls. Increased IGF-II values were associated with a decreased disease-free survival. After tumor removal, both IGF-I and IGF-II levels returned to normal values. In 23 of 45 patients, we obtained tissue specimens and found that all expressed high mRNA level of IGF-II and >IGF-I. Also, isoform A of the insulin receptor (IR-A) was expressed at high level in addition to IGFIR and IR-A/IGFIR hybrids receptors (HR(A)). These receptors were also expressed in OS cell lines, and simultaneous impairment of IGFIR, IR, and Hybrid-Rs by monoclonal antibodies, siRNA, or the tyrosine kinase inhibitor BMS-536924, which blocks both IGFIR and IR, was more effective than selective anti-IGFIR strategies. Also, anti-IGF-II-siRNA treatment in low-serum conditions significantly inhibited MG-63 OS cells that have an autocrine circuit for IGF-II. In summary, IGF-II rather than IGF-I is the predominant growth factor produced by OS cells, and three different receptors (IR-A, HR(A), and IGFIR) act complementarily for an IGF-II-mediated constitutive autocrine loop, in addition to the previously shown IGFIR/IGF-I circuit. Cotargeting IGFIR and IR-A is more effective than targeting IGF-IR alone in inhibiting OS growth. PMID:19258511

  9. Microsporidia-Host Interactions

    PubMed Central

    Szumowski, Suzannah C.; Troemel, Emily R.

    2015-01-01

    Microsporidia comprise one of the largest groups of obligate intracellular pathogens and can infect virtually all animals, but host response to these fungal-related microbes has been poorly understood. Several new studies of the host transcriptional response to microsporidia infection have found infection-induced regulation of genes involved in innate immunity, ubiquitylation, metabolism, and hormonal signaling. In addition, microsporidia have recently been shown to exploit host recycling endocytosis for exit from intestinal cells, and to interact with host degradation pathways. Microsporidia infection has also been shown to profoundly affect behavior in insect hosts. Altogether, these and other recent findings are providing much-needed insight into the underlying mechanisms of microsporidia interaction with host animals. PMID:25847674

  10. 25 CFR 39.1101 - Addition of pre-kindergarten as a weight factor to the Indian School Equalization Formula in...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Addition of pre-kindergarten as a weight factor to the Indian School Equalization Formula in fiscal year 1982. 39.1101 Section 39.1101 Indians BUREAU OF INDIAN... Programs § 39.1101 Addition of pre-kindergarten as a weight factor to the Indian School...

  11. 25 CFR 39.1101 - Addition of pre-kindergarten as a weight factor to the Indian School Equalization Formula in...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Addition of pre-kindergarten as a weight factor to the Indian School Equalization Formula in fiscal year 1982. 39.1101 Section 39.1101 Indians BUREAU OF INDIAN... Programs § 39.1101 Addition of pre-kindergarten as a weight factor to the Indian School...

  12. 25 CFR 39.1101 - Addition of pre-kindergarten as a weight factor to the Indian School Equalization Formula in...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Addition of pre-kindergarten as a weight factor to the Indian School Equalization Formula in fiscal year 1982. 39.1101 Section 39.1101 Indians BUREAU OF INDIAN... Programs § 39.1101 Addition of pre-kindergarten as a weight factor to the Indian School...

  13. 25 CFR 39.1101 - Addition of pre-kindergarten as a weight factor to the Indian School Equalization Formula in...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Addition of pre-kindergarten as a weight factor to the Indian School Equalization Formula in fiscal year 1982. 39.1101 Section 39.1101 Indians BUREAU OF INDIAN... Programs § 39.1101 Addition of pre-kindergarten as a weight factor to the Indian School...

  14. 25 CFR 39.1101 - Addition of pre-kindergarten as a weight factor to the Indian School Equalization Formula in...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Addition of pre-kindergarten as a weight factor to the Indian School Equalization Formula in fiscal year 1982. 39.1101 Section 39.1101 Indians BUREAU OF INDIAN... Programs § 39.1101 Addition of pre-kindergarten as a weight factor to the Indian School...

  15. Exchange of hosts: can agaonid fig wasps reproduce successfully in the figs of non-host Ficus?

    NASA Astrophysics Data System (ADS)

    Yang, Pei; Li, Zongbo; Peng, Yanqiong; Yang, Darong

    2012-03-01

    In the obligate mutualism between figs ( Ficus) and their specific pollinators (Chalcidoidea, Agaonidae), each species of fig wasp typically reproduces in figs of a single host species. Host specificity is maintained largely because pollinators are attracted to tree-specific volatiles released from their host figs, but whether the wasps can reproduce if they enter figs of non-host species is unclear. We investigated the reproductive success of Ceratosolen emarginatus (associated with Ficus auriculata) and Ceratosolen sp. (associated with F. hainanensis) in atypical hosts by experimentally introducing foundresses into host and non-host figs. F. auriculata figs entered by Ceratosolen sp. were more likely to abort than if entered by C. emarginatus, but abortion of F. hainanensis figs was not affected by pollinator species. Single C. emarginatus foundresses produced more but smaller offspring in F. hainanensis than in their normal host. Conversely Ceratosolen sp. produced fewer but larger offspring in F. auriculata than in their normal host, probably as a result of having longer to develop. Mean style length differences, relative to the lengths of the wasps' ovipositors, may have dictated the number of offspring produced, with oviposition made easier by the shorter styles in F. hainanensis figs. Our results imply that, in addition to morphological constraints and tree-specific volatiles, reduced reproductive success in atypical hosts can be another factor maintaining host specificity, but for other species only behavioural changes are required for host switching to occur.

  16. HOST PLANT UTILIZATION, HOST RANGE OSCILLATIONS AND DIVERSIFICATION IN NYMPHALID BUTTERFLIES: A PHYLOGENETIC INVESTIGATION

    PubMed Central

    Nylin, Sören; Slove, Jessica; Janz, Niklas

    2014-01-01

    It has been suggested that phenotypic plasticity is a major factor in the diversification of life, and that variation in host range in phytophagous insects is a good model for investigating this claim. We explore the use of angiosperm plants as hosts for nymphalid butterflies, and in particular the evidence for past oscillations in host range and how they are linked to host shifts and to diversification. At the level of orders of plants, a relatively simple pattern of host use and host shifts emerges, despite the 100 million years of history of the family Nymphalidae. We review the evidence that these host shifts and the accompanying diversifications were associated with transient polyphagous stages, as suggested by the “oscillation hypothesis.” In addition, we investigate all currently polyphagous nymphalid species and demonstrate that the state of polyphagy is rare, has a weak phylogenetic signal, and a very apical distribution in the phylogeny; we argue that these are signs of its transient nature. We contrast our results with data from the bark beetles Dendroctonus, in which a more specialized host use is instead the apical state. We conclude that plasticity in host use is likely to have contributed to diversification in nymphalid butterflies. PMID:24372598

  17. The Glycoproteins of All Filovirus Species Use the Same Host Factors for Entry into Bat and Human Cells but Entry Efficiency Is Species Dependent

    PubMed Central

    Hoffmann, Markus; González Hernández, Mariana; Berger, Elisabeth; Marzi, Andrea; Pöhlmann, Stefan

    2016-01-01

    Ebola and marburgviruses, members of the family Filoviridae, can cause severe hemorrhagic fever in humans. The ongoing Ebola virus (EBOV) disease epidemic in Western Africa claimed more than 11,300 lives and was associated with secondary cases outside Africa, demonstrating that filoviruses pose a global health threat. Bats constitute an important natural reservoir of filoviruses, including viruses of the recently identified Cuevavirus genus within the Filoviridae family. However, the interactions of filoviruses with bat cells are incompletely understood. Here, we investigated whether filoviruses employ different strategies to enter human and bat cells. For this, we examined host cell entry driven by glycoproteins (GP) from all filovirus species into cell lines of human and fruit bat origin. We show that all GPs were able to mediate entry into human and most fruit bat cell lines with roughly comparable efficiency. In contrast, the efficiency of entry into the cell line EidNi/41 derived from a straw-colored fruit bat varied markedly between the GPs of different filovirus species. Furthermore, inhibition studies demonstrated that filoviruses employ the same host cell factors for entry into human, non-human primate and fruit bat cell lines, including cysteine proteases, two pore channels and NPC1 (Niemann-Pick C1 molecule). Finally, processing of GP by furin and the presence of the mucin-like domain in GP were dispensable for entry into both human and bat cell lines. Collectively, these results show that filoviruses rely on the same host cell factors for entry into human and fruit bat cells, although the efficiency of the usage of these factors might differ between filovirus species. PMID:26901159

  18. The Glycoproteins of All Filovirus Species Use the Same Host Factors for Entry into Bat and Human Cells but Entry Efficiency Is Species Dependent.

    PubMed

    Hoffmann, Markus; González Hernández, Mariana; Berger, Elisabeth; Marzi, Andrea; Pöhlmann, Stefan

    2016-01-01

    Ebola and marburgviruses, members of the family Filoviridae, can cause severe hemorrhagic fever in humans. The ongoing Ebola virus (EBOV) disease epidemic in Western Africa claimed more than 11,300 lives and was associated with secondary cases outside Africa, demonstrating that filoviruses pose a global health threat. Bats constitute an important natural reservoir of filoviruses, including viruses of the recently identified Cuevavirus genus within the Filoviridae family. However, the interactions of filoviruses with bat cells are incompletely understood. Here, we investigated whether filoviruses employ different strategies to enter human and bat cells. For this, we examined host cell entry driven by glycoproteins (GP) from all filovirus species into cell lines of human and fruit bat origin. We show that all GPs were able to mediate entry into human and most fruit bat cell lines with roughly comparable efficiency. In contrast, the efficiency of entry into the cell line EidNi/41 derived from a straw-colored fruit bat varied markedly between the GPs of different filovirus species. Furthermore, inhibition studies demonstrated that filoviruses employ the same host cell factors for entry into human, non-human primate and fruit bat cell lines, including cysteine proteases, two pore channels and NPC1 (Niemann-Pick C1 molecule). Finally, processing of GP by furin and the presence of the mucin-like domain in GP were dispensable for entry into both human and bat cell lines. Collectively, these results show that filoviruses rely on the same host cell factors for entry into human and fruit bat cells, although the efficiency of the usage of these factors might differ between filovirus species. PMID:26901159

  19. Parasite host range and the evolution of host resistance.

    PubMed

    Gorter, F A; Hall, A R; Buckling, A; Scanlan, P D

    2015-05-01

    Parasite host range plays a pivotal role in the evolution and ecology of hosts and the emergence of infectious disease. Although the factors that promote host range and the epidemiological consequences of variation in host range are relatively well characterized, the effect of parasite host range on host resistance evolution is less well understood. In this study, we tested the impact of parasite host range on host resistance evolution. To do so, we used the host bacterium Pseudomonas fluorescens SBW25 and a diverse suite of coevolved viral parasites (lytic bacteriophage Φ2) with variable host ranges (defined here as the number of host genotypes that can be infected) as our experimental model organisms. Our results show that resistance evolution to coevolved phages occurred at a much lower rate than to ancestral phage (approximately 50% vs. 100%), but the host range of coevolved phages did not influence the likelihood of resistance evolution. We also show that the host range of both single parasites and populations of parasites does not affect the breadth of the resulting resistance range in a naïve host but that hosts that evolve resistance to single parasites are more likely to resist other (genetically) more closely related parasites as a correlated response. These findings have important implications for our understanding of resistance evolution in natural populations of bacteria and viruses and other host-parasite combinations with similar underlying infection genetics, as well as the development of phage therapy. PMID:25851735

  20. Sequence determination of a new parrot bornavirus-5 strain in Japan: implications of clade-specific sequence diversity in the regions interacting with host factors.

    PubMed

    Komorizono, Ryo; Makino, Akiko; Horie, Masayuki; Honda, Tomoyuki; Tomonaga, Keizo

    2016-06-01

    In this study, the genome sequence of a new parrot bornavirus-5 (PaBV-5) detected in Eclectus roratus was determined. Phylogenetic analysis showed that the genus Bornavirus is divided into three major clades and that PaBV-5 belongs to clade 2, which contains avian viruses that exhibit infectivity to mammalian cells. Sequence comparisons of the regions known to interact with host factors indicated that the clade 2 avian viruses possess sequences intermediate between the clade 1 mammalian viruses and the clade 3 avian viruses, suggesting that the identified regions might contribute to the differences in virological properties between the three clades. PMID:27166599

  1. Type 1 Diabetes in the Spanish Population: additional factors to Class II HLA-DR3 and -DR4

    PubMed Central

    Urcelay, Elena; Santiago, José L; de la Calle, Hermenegildo; Martínez, Alfonso; Méndez, Julián; Ibarra, José M; Maluenda, Carlos; Fernández-Arquero, Miguel; de la Concha, Emilio G

    2005-01-01

    Background The Major Histocompatibility Complex is the main genetic contributor to susceptibility to type 1 diabetes (T1D); genome-wide scans have consistently mapped increased predisposition to this region. The highest disease risk has been associated with HLA-DR3 and HLA-DR4. In particular, the DR3-positive ancestral haplotype 18.2 was reported as highly diabetogenic. We aimed to corroborate whether this haplotype increases the susceptibility conferred by the DQ2-DR3 alleles in a Mediterranean population. We also searched for additional susceptibility factors to the classic DQ2-DR3 and DQ8-DR4. Results Genetic MHC markers were analysed in a case-control study with 302 T1D patients and 529 ethnically matched controls. DR3-TNFa1b5 carrier rate was significantly higher in DR3-positive heterozygous T1D patients than in DR3-positive heterozygous controls (p = 0.0019; odds ratio OR [95% confidence interval CI] = 2.26 [1.3–3.93]). This data was confirmed analysing the allelic frequency, which includes the information corresponding to the DR3-homozygous individuals (p = 0.001; OR = 2.09) and by using the Arlequin software to check the DR3-positive haplotypes (p = 0.004;OR = 1.93). The present results provide strong evidence of a second susceptibility region in the ancestral haplotype 18.2 in the Spanish population. Moreover, we searched for T1D susceptibility factors in addition to the MHC classical ones, within the DR2-DQ6/DR3-DQ2/DR4-DQ8 negative population. Several genetic markers in both MHC class II (DQA1*0101-DQB1*0501 [p = 0.007;OR = 2.81], DQA1*0201-DQB1*0202 [p = 0.03; OR = 2.35]) and III (TNFa2b1 [p = 0.01 OR = 2.74], BAT-2*2 [p = 0.004; OR = 3.19]) were found. These different alleles associated with T1D were not independent and we observed linkage disequilibrium among them leading us to describe two new risk haplotypes (DQA1*0101-DQB1*0501-TNFa2b1 and DQA1*0201-DQB1*0202- BAT-2*2). Finally, we studied a T1D susceptibility/protection marker located in

  2. Rapid Virulence Annotation (RVA): Identification of virulence factors using a bacterial genome library and multiple invertebrate hosts

    PubMed Central

    Waterfield, Nicholas R.; Sanchez-Contreras, Maria; Eleftherianos, Ioannis; Dowling, Andrea; Yang, Guowei; Wilkinson, Paul; Parkhill, Julian; Thomson, Nicholas; Reynolds, Stuart E.; Bode, Helge B.; Dorus, Steven; ffrench-Constant, Richard H.

    2008-01-01

    Current sequence databases now contain numerous whole genome sequences of pathogenic bacteria. However, many of the predicted genes lack any functional annotation. We describe an assumption-free approach, Rapid Virulence Annotation (RVA), for the high-throughput parallel screening of genomic libraries against four different taxa: insects, nematodes, amoeba, and mammalian macrophages. These hosts represent different aspects of both the vertebrate and invertebrate immune system. Here, we apply RVA to the emerging human pathogen Photorhabdus asymbiotica using “gain of toxicity” assays of recombinant Escherichia coli clones. We describe a wealth of potential virulence loci and attribute biological function to several putative genomic islands, which may then be further characterized using conventional molecular techniques. The application of RVA to other pathogen genomes promises to ascribe biological function to otherwise uncharacterized virulence genes. PMID:18838673

  3. Randomised Controlled Feasibility Trial of an Evidence-Informed Behavioural Intervention for Obese Adults with Additional Risk Factors

    PubMed Central

    Sniehotta, Falko F.; Dombrowski, Stephan U.; Avenell, Alison; Johnston, Marie; McDonald, Suzanne; Murchie, Peter; Ramsay, Craig R.; Robertson, Kim; Araujo-Soares, Vera

    2011-01-01

    Background Interventions for dietary and physical activity changes in obese adults may be less effective for participants with additional obesity-related risk factors and co-morbidities than for otherwise healthy individuals. This study aimed to test the feasibility and acceptability of the recruitment, allocation, measurement, retention and intervention procedures of a randomised controlled trial of an intervention to improve physical activity and dietary practices amongst obese adults with additional obesity related risk factors. Method Pilot single centre open-labelled outcome assessor-blinded randomised controlled trial of obese (Body Mass Index (BMI)≥30 kg/m2) adults (age≥18 y) with obesity related co-morbidities such as type 2 diabetes, impaired glucose tolerance or hypertension. Participants were randomly allocated to a manual-based group intervention or a leaflet control condition in accordance to a 2∶1 allocation ratio. Primary outcome was acceptability and feasibility of trial procedures, secondary outcomes included measures of body composition, physical activity, food intake and psychological process measures. Results Out of 806 potentially eligible individuals identified through list searches in two primary care general medical practices N = 81 participants (63% female; mean-age = 56.56(11.44); mean-BMI = 36.73(6.06)) with 2.35(1.47) co-morbidities were randomised. Scottish Index of Multiple Deprivation (SIMD) was the only significant predictor of providing consent to take part in the study (higher chances of consent for invitees with lower levels of deprivation). Participant flowcharts, qualitative and quantitative feedback suggested good acceptance and feasibility of intervention procedures but 34.6% of randomised participants were lost to follow-up due to overly high measurement burden and sub-optimal retention procedures. Participants in the intervention group showed positive trends for most psychological, behavioural and body

  4. Sodium Benzoate, a Metabolite of Cinnamon and a Food Additive, Upregulates Ciliary Neurotrophic Factor in Astrocytes and Oligodendrocytes.

    PubMed

    Modi, Khushbu K; Jana, Malabendu; Mondal, Susanta; Pahan, Kalipada

    2015-11-01

    Ciliary neurotrophic factor (CNTF) is a promyelinating trophic factor that plays an important role in multiple sclerosis (MS). However, mechanisms by which CNTF expression could be increased in the brain are poorly understood. Recently we have discovered anti-inflammatory and immunomodulatory activities of sodium benzoate (NaB), a metabolite of cinnamon and a widely-used food additive. Here, we delineate that NaB is also capable of increasing the mRNA and protein expression of CNTF in primary mouse astrocytes and oligodendrocytes and primary human astrocytes. Accordingly, oral administration of NaB and cinnamon led to the upregulation of astroglial and oligodendroglial CNTF in vivo in mouse brain. Induction of experimental allergic encephalomyelitis, an animal model of MS, reduced the level of CNTF in the brain, which was restored by oral administration of cinnamon. While investigating underlying mechanisms, we observed that NaB induced the activation of protein kinase A (PKA) and H-89, an inhibitor of PKA, abrogated NaB-induced expression of CNTF. The activation of cAMP response element binding (CREB) protein by NaB, the recruitment of CREB and CREB-binding protein to the CNTF promoter by NaB and the abrogation of NaB-induced expression of CNTF in astrocytes by siRNA knockdown of CREB suggest that NaB increases the expression of CNTF via the activation of CREB. These results highlight a novel myelinogenic property of NaB and cinnamon, which may be of benefit for MS and other demyelinating disorders. PMID:26399250

  5. Analysis of host genetic factors influencing African trypanosome species infection in a cohort of Tanzanian Bos indicus cattle.

    PubMed

    Karimuribo, Esron D; Morrison, Liam J; Black, Alana; Turner, C Michael R; Kambarage, Dominic M; Ballingall, Keith T

    2011-06-30

    Trypanosomosis caused by infection with protozoan parasites of the genus Trypanosoma is a major health constraint to cattle production in many African countries. One hundred and seventy one Bos indicus cattle from traditional pastoral Maasai (87) and more intensively managed Boran (84) animals in Tanzania were screened by PCR for the presence of African animal trypanosomes (Trypanosoma congolense, Trypanosoma vivax and Trypanosoma brucei), using blood samples archived on FTA cards. All cattle screened for trypanosomes were also genotyped at the highly polymorphic major histocompatibility complex (MHC) class II DRB3 locus to investigate possible associations between host MHC and trypanosome infection. Overall, 23.4% of the 171 cattle tested positive for at least one of the three trypanosome species. The prevalence of individual trypanosome species was 8.8% (T. congolense), 4.7% (T. vivax) and 15.8% (T. brucei). The high prevalence of T. brucei compared with T. congolense and T. vivax was unexpected as this species has previously been considered to be of lesser importance in terms of African bovine trypanosomosis. Significantly higher numbers of Maasai cattle were infected with T. brucei (23.0%, p=0.009) and T. congolense (13.8%, p=0.019) compared with Boran cattle (8.3% and 3.6%, respectively). Analysis of BoLA-DRB3 diversity in this cohort identified extensive allelic diversity. Thirty-three BoLA-DRB3 PCR-RFLP defined alleles were identified. One allele (DRB3*15) was significantly associated with an increased risk (odds ratio, OR=2.71, p=0.034) of T. brucei infection and three alleles (DRB3*35, *16 and *23) were associated with increased risk of T. congolense infection. While further work is required to dissect the role of these alleles in susceptibility to T. brucei and T. congolense infections, this study demonstrates the utility of FTA archived blood samples in combined molecular analyses of both host and pathogen. PMID:21377802

  6. Risk Factors for Steroid-Refractory Acute Graft-versus-Host Disease after Allogeneic Stem Cell Transplantation from Matched Related or Unrelated Donors.

    PubMed

    Calmettes, Claire; Vigouroux, Stéphane; Labopin, Myriam; Tabrizi, Reza; Turlure, Pascal; Lafarge, Xavier; Marit, Gérald; Pigneux, Arnaud; Leguay, Thibaut; Bouabdallah, Krimo; Dilhuydy, Marie-Sarah; Duclos, Cédric; Mohr, Catherine; Lascaux, Axelle; Dumas, Pierre-Yves; Dimicoli-Salazar, Sophie; Saint-Lézer, Arnaud; Milpied, Noël

    2015-05-01

    We performed a retrospective study to identify pretransplantation risk factors for steroid-refractory (SR) acute graft-versus host disease (aGVHD) after allogeneic stem cell transplantation from matched donors in 630 adult patients who underwent transplantation at our center between 2000 and 2012. The cumulative incidence (CI) of SR aGVHD was 11.3% ± 2.3%. The identified independent risk factors were matched unrelated donor (hazard ratio [HR], 2.52; P = .001), female donor for male recipient (HR, 1.84; P = .023) and absence of antithymocyte globulin (HR, 2.02; P = .005). Three risk groups were defined according to the presence of these risk factors. In the whole cohort, the CI of SR aGVHD was 3.5% ± 1.7% in the low-risk group (0 risk factor, n = 115), 9.3% ± 1.6% in the intermediate-risk group (1 risk factor, n = 323), and 19.3% ± 2.9% in the high-risk group (2 or 3 risk factors, n = 192). Our study suggests that pretransplantation characteristics might help identify patients at high risk for SR aGVHD. A risk adapted first-line treatment of aGVHD could be evaluated in those patients. PMID:25617807

  7. Additional diagnostic and clinical value of anti-cyclic citrullinated peptide antibodies compared with rheumatoid factor isotypes in rheumatoid arthritis.

    PubMed

    Vallbracht, Inka; Helmke, Klaus

    2005-07-01

    In the past decade significant advantages have been made in the treatment of rheumatoid arthritis (RA) and therapeutic strategies have changed a lot. These days, highly effective disease modifying anti-rheumatic drugs enable intervention early in the disease process, in order to prevent major joint damage. For years, serological support in the diagnosis of RA has been limited to the presence of rheumatoid factors, although not very specific for RA. During the last years a variety of circulating non-RF antibodies have been discovered and reported to be of potential diagnostic value. CCP2 proved to be a very disease-specific and even sensitive marker for RA. In addition to the diagnostic properties, CCP showed to be a good prognostic marker, CCP helps to predict the erosive or nonerosive progression of the disease, and CCP is already present early in the disease. This diagnostic tool enables the clinician to choose the optimal therapeutic management for each single RA patient. PMID:16081030

  8. Are delta-aminolevulinate dehydratase inhibition and metal concentrations additional factors for the age-related cognitive decline?

    PubMed

    Baierle, Marília; Charão, Mariele F; Göethel, Gabriela; Barth, Anelise; Fracasso, Rafael; Bubols, Guilherme; Sauer, Elisa; Campanharo, Sarah C; Rocha, Rafael C C; Saint'Pierre, Tatiana D; Bordignon, Suelen; Zibetti, Murilo; Trentini, Clarissa M; Avila, Daiana S; Gioda, Adriana; Garcia, Solange C

    2014-01-01

    Aging is often accompanied by cognitive impairments and influenced by oxidative status and chemical imbalances. Thus, this study was conducted to examine whether age-related cognitive deficit is associated with oxidative damage, especially with inhibition of the enzyme delta-aminolevulinate dehydratase (ALA-D), as well as to verify the influence of some metals in the enzyme activity and cognitive performance. Blood ALA-D activity, essential (Fe, Zn, Cu, Se) and non-essential metals (Pb, Cd, Hg, As, Cr, Ni, V) were measured in 50 elderly and 20 healthy young subjects. Cognitive function was assessed by tests from Consortium to Establish a Registry for Alzheimer's Disease (CERAD) battery and other. The elderly group presented decreased ALA-D activity compared to the young group. The index of ALA-D reactivation was similar to both study groups, but negatively associated with metals. The mean levels of essential metals were within the reference values, while the most toxic metals were above them in both groups. Cognitive function impairments were observed in elderly group and were associated with decreased ALA-D activity, with lower levels of Se and higher levels of toxic metals (Hg and V). Results suggest that the reduced ALA-D activity in elderly can be an additional factor involved in cognitive decline, since its inhibition throughout life could lead to accumulation of the neurotoxic compound ALA. Toxic metals were found to contribute to cognitive decline and also to influence ALA-D reactivation. PMID:25329536

  9. The cis-acting replication element of the Hepatitis C virus genome recruits host factors that influence viral replication and translation.

    PubMed

    Ríos-Marco, Pablo; Romero-López, Cristina; Berzal-Herranz, Alfredo

    2016-01-01

    The cis-acting replication element (CRE) of the hepatitis C virus (HCV) RNA genome is a region of conserved sequence and structure at the 3' end of the open reading frame. It participates in a complex and dynamic RNA-RNA interaction network involving, among others, essential functional domains of the 3' untranslated region and the internal ribosome entry site located at the 5' terminus of the viral genome. A proper balance between all these contacts is critical for the control of viral replication and translation, and is likely dependent on host factors. Proteomic analyses identified a collection of proteins from a hepatoma cell line as CRE-interacting candidates. A large fraction of these were RNA-binding proteins sharing highly conserved RNA recognition motifs. The vast majority of these proteins were validated by bioinformatics tools that consider RNA-protein secondary structure. Further characterization of representative proteins indicated that hnRNPA1 and HMGB1 exerted negative effects on viral replication in a subgenomic HCV replication system. Furthermore DDX5 and PARP1 knockdown reduced the HCV IRES activity, suggesting an involvement of these proteins in HCV translation. The identification of all these host factors provides new clues regarding the function of the CRE during viral cycle progression. PMID:27165399

  10. The cis-acting replication element of the Hepatitis C virus genome recruits host factors that influence viral replication and translation

    PubMed Central

    Ríos-Marco, Pablo; Romero-López, Cristina; Berzal-Herranz, Alfredo

    2016-01-01

    The cis-acting replication element (CRE) of the hepatitis C virus (HCV) RNA genome is a region of conserved sequence and structure at the 3′ end of the open reading frame. It participates in a complex and dynamic RNA-RNA interaction network involving, among others, essential functional domains of the 3′ untranslated region and the internal ribosome entry site located at the 5′ terminus of the viral genome. A proper balance between all these contacts is critical for the control of viral replication and translation, and is likely dependent on host factors. Proteomic analyses identified a collection of proteins from a hepatoma cell line as CRE-interacting candidates. A large fraction of these were RNA-binding proteins sharing highly conserved RNA recognition motifs. The vast majority of these proteins were validated by bioinformatics tools that consider RNA-protein secondary structure. Further characterization of representative proteins indicated that hnRNPA1 and HMGB1 exerted negative effects on viral replication in a subgenomic HCV replication system. Furthermore DDX5 and PARP1 knockdown reduced the HCV IRES activity, suggesting an involvement of these proteins in HCV translation. The identification of all these host factors provides new clues regarding the function of the CRE during viral cycle progression. PMID:27165399

  11. MC1R variation and melanoma risk in relation to host/clinical and environmental factors in CDKN2A positive and negative melanoma patients.

    PubMed

    Ghiorzo, Paola; Bonelli, Luigina; Pastorino, Lorenza; Bruno, William; Barile, Monica; Andreotti, Virginia; Nasti, Sabina; Battistuzzi, Linda; Grosso, Marco; Bianchi-Scarrà, Giovanna; Queirolo, Paola

    2012-09-01

    Host, environmental and genetic factors differently modulate cutaneous melanoma (CM) risk across populations. Currently, the main genetic risk determinants are germline mutations in the major known high-risk susceptibility genes, CDKN2A and CDK4, and variants of the low-risk gene MC1R, which is key in the pigmentation process. This case-control study aimed at investigating the influence of the main host and environmental risk factors and of MC1R variation on CM risk in 390 CDKN2A-negative and 49 CDKN2A-positive Italian individuals. Multivariate analysis showed that MC1R variation, number of nevi and childhood sunburns doubled CM risk in CDKN2A-negative individuals. In CDKN2A-positive individuals, family history of CM and presence of atypical nevi, rather than MC1R status, modified risk (20.75- and 2.83-fold, respectively). Occupational sun exposure increased CM risk (three to sixfold) in both CDKN2A-negative and CDKN2A-positive individuals, reflecting the occupational habits of the Ligurian population and the geographical position of Liguria. PMID:22804906

  12. Comparative Sigma Factor-mRNA Levels in Mycobacterium marinum under Stress Conditions and during Host Infection.

    PubMed

    Pettersson, B M Fredrik; Das, Sarbashis; Behra, Phani Rama Krishna; Jordan, Heather R; Ramesh, Malavika; Mallick, Amrita; Root, Kate M; Cheramie, Martin N; de la Cruz Melara, Irma; Small, Pamela L C; Dasgupta, Santanu; Ennis, Don G; Kirsebom, Leif A

    2015-01-01

    We have used RNASeq and qRT-PCR to study mRNA levels for all σ-factors in different Mycobacterium marinum strains under various growth and stress conditions. We also studied their levels in M. marinum from infected fish and mosquito larvae. The annotated σ-factors were expressed and transcripts varied in relation to growth and stress conditions. Some were highly abundant such as sigA, sigB, sigC, sigD, sigE and sigH while others were not. The σ-factor mRNA profiles were similar after heat stress, during infection of fish and mosquito larvae. The similarity also applies to some of the known heat shock genes such as the α-crystallin gene. Therefore, it seems probable that the physiological state of M. marinum is similar when exposed to these different conditions. Moreover, the mosquito larvae data suggest that this is the state that the fish encounter when infected, at least with respect to σ-factor mRNA levels. Comparative genomic analysis of σ-factor gene localizations in three M. marinum strains and Mycobacterium tuberculosis H37Rv revealed chromosomal rearrangements that changed the localization of especially sigA, sigB, sigD, sigE, sigF and sigJ after the divergence of these two species. This may explain the variation in species-specific expression upon exposure to different growth conditions. PMID:26445268

  13. Comparative Sigma Factor-mRNA Levels in Mycobacterium marinum under Stress Conditions and during Host Infection

    PubMed Central

    Pettersson, B. M. Fredrik; Das, Sarbashis; Behra, Phani Rama Krishna; Jordan, Heather R.; Ramesh, Malavika; Mallick, Amrita; Root, Kate M.; Cheramie, Martin N.; de la Cruz Melara, Irma; Small, Pamela L. C.; Dasgupta, Santanu; Ennis, Don G.; Kirsebom, Leif A.

    2015-01-01

    We have used RNASeq and qRT-PCR to study mRNA levels for all σ-factors in different Mycobacterium marinum strains under various growth and stress conditions. We also studied their levels in M. marinum from infected fish and mosquito larvae. The annotated σ-factors were expressed and transcripts varied in relation to growth and stress conditions. Some were highly abundant such as sigA, sigB, sigC, sigD, sigE and sigH while others were not. The σ-factor mRNA profiles were similar after heat stress, during infection of fish and mosquito larvae. The similarity also applies to some of the known heat shock genes such as the α-crystallin gene. Therefore, it seems probable that the physiological state of M. marinum is similar when exposed to these different conditions. Moreover, the mosquito larvae data suggest that this is the state that the fish encounter when infected, at least with respect to σ-factor mRNA levels. Comparative genomic analysis of σ-factor gene localizations in three M. marinum strains and Mycobacterium tuberculosis H37Rv revealed chromosomal rearrangements that changed the localization of especially sigA, sigB, sigD, sigE, sigF and sigJ after the divergence of these two species. This may explain the variation in species-specific expression upon exposure to different growth conditions. PMID:26445268

  14. Post-Transcriptional Regulation of the Sef1 Transcription Factor Controls the Virulence of Candida albicans in Its Mammalian Host

    PubMed Central

    Chen, Changbin; Noble, Suzanne M.

    2012-01-01

    The yeast Candida albicans transitions between distinct lifestyles as a normal component of the human gastrointestinal microbiome and the most common agent of disseminated fungal disease. We previously identified Sef1 as a novel Cys6Zn2 DNA binding protein that plays an essential role in C. albicans virulence by activating the transcription of iron uptake genes in iron-poor environments such as the host bloodstream and internal organs. Conversely, in the iron-replete gastrointestinal tract, persistence as a commensal requires the transcriptional repressor Sfu1, which represses SEF1 and genes for iron uptake. Here, we describe an unexpected, transcription-independent role for Sfu1 in the direct inhibition of Sef1 function through protein complex formation and localization in the cytoplasm, where Sef1 is destabilized. Under iron-limiting conditions, Sef1 forms an alternative complex with the putative kinase, Ssn3, resulting in its phosphorylation, nuclear localization, and transcriptional activity. Analysis of sfu1 and ssn3 mutants in a mammalian model of disseminated candidiasis indicates that these post-transcriptional regulatory mechanisms serve as a means for precise titration of C. albicans virulence. PMID:23133381

  15. TUMOR AND HOST FACTORS THAT MAY LIMIT EFFICACY OF CHEMOTHERAPY IN NON-SMALL CELL AND SMALL CELL LUNG CANCER

    PubMed Central

    Stewart, David J.

    2010-01-01

    While chemotherapy provides useful palliation, advanced lung cancer remains incurable since those tumors that are initially sensitive to therapy rapidly develop acquired resistance. Resistance may arise from impaired drug delivery, extracellular factors, decreased drug uptake into tumor cells, increased drug efflux, drug inactivation by detoxifying factors, decreased drug activation or binding to target, altered target, increased damage repair, tolerance of damage, decreased proapoptotic factors, increased antiapoptotic factors, or altered cell cycling or transcription factors. Factors for which there is now substantial clinical evidence of a link to small cell lung cancer (SCLC) resistance to chemotherapy include MRP (for platinum-based combination chemotherapy) and MDR1/P-gp (for non-platinum agents). SPECT MIBI and Tc-TF scanning appears to predict chemotherapy benefit in SCLC. In non-small cell lung cancer (NSCLC), the strongest clinical evidence is for taxane resistance with elevated expression or mutation of class III β-tubulin (and possibly α tubulin), platinum resistance and expression of ERCC1 or BCRP, gemcitabine resistance and RRM1 expression, and resistance to several agents and COX-2 expression (although COX-2 inhibitors have had minimal impact on drug efficacy clinically). Tumors expressing high BRCA1 may have increased resistance to platinums but increased sensitivity to taxanes. Limited early clinical data suggest that chemotherapy resistance in NSCLC may also be increased with decreased expression of cyclin B1 or of Eg5, or with increased expression of ICAM, matrilysin, osteopontin, DDH, survivin, PCDGF, caveolin-1, p21WAF1/CIP1, or 14-3-3sigma, and that IGF-1R inhibitors may increase efficacy of chemotherapy, particularly in squamous cell carcinomas. Equivocal data (with some positive studies but other negative studies) suggest that NSCLC tumors with some EGFR mutations may have increased sensitivity to chemotherapy, while K-ras mutations and

  16. Tumor and host factors that may limit efficacy of chemotherapy in non-small cell and small cell lung cancer.

    PubMed

    Stewart, David J

    2010-09-01

    While chemotherapy provides useful palliation, advanced lung cancer remains incurable since those tumors that are initially sensitive to therapy rapidly develop acquired resistance. Resistance may arise from impaired drug delivery, extracellular factors, decreased drug uptake into tumor cells, increased drug efflux, drug inactivation by detoxifying factors, decreased drug activation or binding to target, altered target, increased damage repair, tolerance of damage, decreased proapoptotic factors, increased antiapoptotic factors, or altered cell cycling or transcription factors. Factors for which there is now substantial clinical evidence of a link to small cell lung cancer (SCLC) resistance to chemotherapy include MRP (for platinum-based combination chemotherapy) and MDR1/P-gp (for non-platinum agents). SPECT MIBI and Tc-TF scanning appears to predict chemotherapy benefit in SCLC. In non-small cell lung cancer (NSCLC), the strongest clinical evidence is for taxane resistance with elevated expression or mutation of class III beta-tubulin (and possibly alpha tubulin), platinum resistance and expression of ERCC1 or BCRP, gemcitabine resistance and RRM1 expression, and resistance to several agents and COX-2 expression (although COX-2 inhibitors have had minimal impact on drug efficacy clinically). Tumors expressing high BRCA1 may have increased resistance to platinums but increased sensitivity to taxanes. Limited early clinical data suggest that chemotherapy resistance in NSCLC may also be increased with decreased expression of cyclin B1 or of Eg5, or with increased expression of ICAM, matrilysin, osteopontin, DDH, survivin, PCDGF, caveolin-1, p21WAF1/CIP1, or 14-3-3sigma, and that IGF-1R inhibitors may increase efficacy of chemotherapy, particularly in squamous cell carcinomas. Equivocal data (with some positive studies but other negative studies) suggest that NSCLC tumors with some EGFR mutations may have increased sensitivity to chemotherapy, while K-ras mutations

  17. HIV-1 Resistance to the Capsid-Targeting Inhibitor PF74 Results in Altered Dependence on Host Factors Required for Virus Nuclear Entry

    PubMed Central

    Zhou, Jing; Price, Amanda J.; Halambage, Upul D.; James, Leo C.

    2015-01-01

    ABSTRACT During HIV-1 infection of cells, the viral capsid plays critical roles in reverse transcription and nuclear entry of the virus. The capsid-targeting small molecule PF74 inhibits HIV-1 at early stages of infection. HIV-1 resistance to PF74 is complex, requiring multiple amino acid substitutions in the viral CA protein. Here we report the identification and analysis of a novel PF74-resistant mutant encoding amino acid changes in both domains of CA, three of which are near the pocket where PF74 binds. Interestingly, the mutant virus retained partial PF74 binding, and its replication was stimulated by the compound. The mutant capsid structure was not significantly perturbed by binding of PF74; rather, the mutations inhibited capsid interactions with CPSF6 and Nup153 and altered HIV-1 dependence on these host factors and on TNPO3. Moreover, the replication of the mutant virus was markedly impaired in activated primary CD4+ T cells and macrophages. Our results suggest that HIV-1 escapes a capsid-targeting small molecule inhibitor by altering the virus's dependence on host factors normally required for entry into the nucleus. They further imply that clinical resistance to inhibitors targeting the PF74 binding pocket is likely to be strongly limited by functional constraints on HIV-1 evolution. IMPORTANCE The HIV-1 capsid plays critical roles in early steps of infection and is an attractive target for therapy. Here we show that selection for resistance to a capsid-targeting small molecule inhibitor can result in viral dependence on the compound. The mutant virus was debilitated in primary T cells and macrophages—cellular targets of infection in vivo. The mutations also altered the virus's dependence on cellular factors that are normally required for HIV-1 entry into the nucleus. This work provides new information regarding mechanisms of HIV-1 resistance that should be useful in efforts to develop clinically useful drugs targeting the HIV-1 capsid. PMID:26109731

  18. Circulating Angiogenic Factors Associated with Response and Survival in Patients with Acute Graft-Versus-Host Disease: Results from BMT CTN 0302 and 0802

    PubMed Central

    Holtan, Shernan G.; Verneris, Michael R.; Schultz, Kirk R.; Newell, Laura F.; Meyers, Gabrielle; He, Fiona; DeFor, Todd E.; Vercellotti, Gregory M.; Slungaard, Arne; MacMillan, Margaret L.; Cooley, Sarah A.; Blazar, Bruce R.; Panoskaltsis-Mortari, Angela; Weisdorf, Daniel J.

    2015-01-01

    Circulating angiogenic factors (AF) reflect tissue healing capacity, although some AF can also contribute to inflammation and are indicative of endothelial dysfunction. The AF milieu in acute graft-versus-host disease (aGVHD) has not been broadly characterized. We hypothesized that patients with abundant AF involved in repair/regeneration vs. those mediating damage/inflammation would have improved outcomes. Circulating AF known predominantly for repair/regeneration (epidermal growth factor [EGF], fibroblast growth factor-1 and -2, heparin binding-EGF-like growth factor, vascular endothelial growth factor-A, -C, and -D) and for damage/inflammation (angiopoietin-2, endothelin-1, soluble endoglin [sEng], follistatin [FS], leptin, placental growth factor [PlGF]) were measured in a discovery set of HCT recipients with grade III/IV aGVHD versus controls, then validated in two aGVHD cohorts enrolled in Blood and Marrow Transplant Clinical Trials Network (BMT CTN) trials 0302 (N=105, serum) and 0802 (N=158, plasma) versus controls without aGVHD (N=53, serum). Levels of EGF and VEGF-A were lower than controls at the onset of aGVHD in both trials and higher with complete response to first-line aGVHD therapy in CTN 0802. FS and PlGF were elevated in aGVHD measured in either serum or plasma. At day 28 after initial aGVHD therapy, elevated FS was an independent negative prognostic factor for survival in both cohorts (hazard ratio 9.3 in CTN 0302, 2.8 in CTN 0802). These data suggest that circulating AF are associated with clinical outcomes after aGVHD and thus may contribute to both pathogenesis and recovery. PMID:25759146

  19. A Plasmodium falciparum PHIST protein binds the virulence factor PfEMP1 and comigrates to knobs on the host cell surface

    PubMed Central

    Oberli, Alexander; Slater, Leanne M.; Cutts, Erin; Brand, Françoise; Mundwiler-Pachlatko, Esther; Rusch, Sebastian; Masik, Martin F. G.; Erat, Michèle C.; Beck, Hans-Peter; Vakonakis, Ioannis

    2014-01-01

    Uniquely among malaria parasites, Plasmodium falciparum-infected erythrocytes (iRBCs) develop membrane protrusions, known as knobs, where the parasite adhesion receptor P. falciparum erythrocyte membrane protein 1 (PfEMP1) clusters. Knob formation and the associated iRBC adherence to host endothelium are directly linked to the severity of malaria and are functional manifestations of protein export from the parasite to the iRBC. A family of exported proteins featuring Plasmodium helical interspersed subtelomeric (PHIST) domains has attracted attention, with members being implicated in host-parasite protein interactions and differentially regulated in severe disease and among parasite isolates. Here, we show that PHIST member PFE1605w binds the PfEMP1 intracellular segment directly with Kd = 5 ± 0.6 μM, comigrates with PfEMP1 during export, and locates in knobs. PHIST variants that do not locate in knobs (MAL8P1.4) or bind PfEMP1 30 times more weakly (PFI1780w) used as controls did not display the same pattern. We resolved the first crystallographic structure of a PHIST protein and derived a partial model of the PHIST-PfEMP1 interaction from nuclear magnetic resonance. We propose that PFE1605w reinforces the PfEMP1-cytoskeletal connection in knobs and discuss the possible role of PHIST proteins as interaction hubs in the parasite exportome.—Oberli, A., Slater, L. M., Cutts, E., Brand, F., Mundwiler-Pachlatko, E., Rusch, S., Masik, M. F. G., Erat, M. C., Beck, H.-P., Vakonakis, I. A Plasmodium falciparum PHIST protein binds the virulence factor PfEMP1 and comigrates to knobs on the host cell surface. PMID:24983468

  20. Yip1A, a Novel Host Factor for the Activation of the IRE1 Pathway of the Unfolded Protein Response during Brucella Infection

    PubMed Central

    Taguchi, Yuki; Imaoka, Koichi; Kataoka, Michiyo; Uda, Akihiko; Nakatsu, Daiki; Horii-Okazaki, Sakuya; Kunishige, Rina; Kano, Fumi; Murata, Masayuki

    2015-01-01

    Brucella species replicate within host cells in the form of endoplasmic reticulum (ER)-derived vacuoles. The mechanisms by which the bacteria are sequestered into such vacuoles and obtain a continuous membrane supply for their replication remain to be elucidated. In the present study, we provided several lines of evidence that demonstrate the mechanism by which B. abortus acquires the ER-derived membrane. First, during Brucella infection, the IRE1 pathway, but not the PERK and ATF6 pathways, of the unfolded protein response (UPR) was activated in a time-dependent manner, and the COPII vesicle components Sar1, Sec23, and Sec24D were upregulated. Second, a marked accretion of ER-derived vacuoles was observed around replicating bacteria using fluorescent microscopy and electron microscopy. Third, we identified a novel host factor, Yip1A, for the activation of the IRE1 pathway in response to both tunicamycin treatment and infection with B. abortus. We found that Yip1A is responsible for the phosphorylation of IRE1 through high-order assembly of Ire1 molecules at ER exit sites (ERES) under the UPR conditions. In Yip1A-knockdown cells, B. abortus failed to generate the ER-derived vacuoles, and remained in endosomal/lysosomal compartments. These results indicate that the activation of the IRE1 pathway and the subsequent formation of ER-derived vacuoles are critical for B. abortus to establish a safe replication niche, and that Yip1A is indispensable for these processes. Furthermore, we showed that the autophagy-related proteins Atg9 and WIPI1, but not DFCP1, were required for the biogenesis of the ER-derived membrane compartments.  On the basis of our findings, we propose a model for intracellular Brucella replication that exploits the host UPR and ER-derived vacuole formation machineries, both of which depend on Yip1A-mediated IRE1 activation. PMID:25742138

  1. Elongation Factor-1α Is a Novel Protein Associated with Host Cell Invasion and a Potential Protective Antigen of Cryptosporidium parvum *

    PubMed Central

    Matsubayashi, Makoto; Teramoto-Kimata, Isao; Uni, Shigehiko; Lillehoj, Hyun S.; Matsuda, Haruo; Furuya, Masaru; Tani, Hiroyuki; Sasai, Kazumi

    2013-01-01

    The phylum Apicomplexa comprises obligate intracellular parasites that infect vertebrates. All invasive forms of Apicomplexa possess an apical complex, a unique assembly of organelles localized to the anterior end of the cell and involved in host cell invasion. Previously, we generated a chicken monoclonal antibody (mAb), 6D-12-G10, with specificity for an antigen located in the apical cytoskeleton of Eimeria acervulina sporozoites. This antigen was highly conserved among Apicomplexan parasites, including other Eimeria spp., Toxoplasma, Neospora, and Cryptosporidium. In the present study, we identified the apical cytoskeletal antigen of Cryptosporidium parvum (C. parvum) and further characterized this antigen in C. parvum to assess its potential as a target molecule against cryptosporidiosis. Indirect immunofluorescence demonstrated that the reactivity of 6D-12-G10 with C. parvum sporozoites was similar to those of anti-β- and anti-γ-tubulins antibodies. Immunoelectron microscopy with the 6D-12-G10 mAb detected the antigen both on the sporozoite surface and underneath the inner membrane at the apical region of zoites. The 6D-12-G10 mAb significantly inhibited in vitro host cell invasion by C. parvum. MALDI-TOF/MS and LC-MS/MS analysis of tryptic peptides revealed that the mAb 6D-12-G10 target antigen was elongation factor-1α (EF-1α). These results indicate that C. parvum EF-1α plays an essential role in mediating host cell entry by the parasite and, as such, could be a candidate vaccine antigen against cryptosporidiosis. PMID:24085304

  2. Host innate inflammatory factors and staphylococcal protein A influence the duration of human Staphylococcus aureus nasal carriage

    PubMed Central

    Cole, Amy L.; Muthukrishnan, Gowrishankar; Chong, Christine; Beavis, Ashley; Eade, Colleen R.; Wood, Matthew P.; Deichen, Michael G.; Cole, Alexander M.

    2016-01-01

    Human Staphylococcus aureus (SA) nasal carriage provides a reservoir for the dissemination of infectious strains; however, factors regulating the establishment and persistence of nasal colonization are mostly unknown. We measured carriage duration and nasal fluid inflammatory markers after nasally inoculating healthy participants with their previously isolated SA strains. Ten out of 15 studies resulted in rapid clearance (9±6 days) that corresponded with upregulated chemokines, growth factors, and predominantly Th1-type cytokines, but not IL-17. Nasal SA persistence corresponded with elevated baseline levels of MIP-1β, IL-1β, and IL-6, no induction of inflammatory factors post-inoculation, and decreased IL-1RA:IL-1β ratio. SA-expressed staphylococcal protein A (SpA) levels correlated positively with carriage duration. Competitive inoculation studies revealed that isogenic SpA knockout (ΔSpA) strains were cleared faster than wild-type only in participants with upregulated inflammatory markers post-inoculation. The remaining participants did not mount an inflammatory response and did not clear either strain. ΔSpA strains demonstrated lower growth rates in carrier nasal fluids and lower survival rates when incubated with neutrophils. Collectively, the presented studies identify innate immune effectors that cooperatively modulate nasal carriage duration, and confirm SpA as a bacterial co-determinant of SA nasal carriage. PMID:26838052

  3. Identification and Functional Characterization of Rca1, a Transcription Factor Involved in both Antifungal Susceptibility and Host Response in Candida albicans

    PubMed Central

    Vandeputte, Patrick; Pradervand, Sylvain; Ischer, Françoise; Coste, Alix T.; Ferrari, Sélène; Harshman, Keith

    2012-01-01

    The identification of novel transcription factors associated with antifungal response may allow the discovery of fungus-specific targets for new therapeutic strategies. A collection of 241 Candida albicans transcriptional regulator mutants was screened for altered susceptibility to fluconazole, caspofungin, amphotericin B, and 5-fluorocytosine. Thirteen of these mutants not yet identified in terms of their role in antifungal response were further investigated, and the function of one of them, a mutant of orf19.6102 (RCA1), was characterized by transcriptome analysis. Strand-specific RNA sequencing and phenotypic tests assigned Rca1 as the regulator of hyphal formation through the cyclic AMP/protein kinase A (cAMP/PKA) signaling pathway and the transcription factor Efg1, but also probably through its interaction with a transcriptional repressor, most likely Tup1. The mechanisms responsible for the high level of resistance to caspofungin and fluconazole observed resulting from RCA1 deletion were investigated. From our observations, we propose that caspofungin resistance was the consequence of the deregulation of cell wall gene expression and that fluconazole resistance was linked to the modulation of the cAMP/PKA signaling pathway activity. In conclusion, our large-scale screening of a C. albicans transcription factor mutant collection allowed the identification of new effectors of the response to antifungals. The functional characterization of Rca1 assigned this transcription factor and its downstream targets as promising candidates for the development of new therapeutic strategies, as Rca1 influences host sensing, hyphal development, and antifungal response. PMID:22581526

  4. Pediatric spinal epidural abscess in an immunocompetent host without risk factors: Case report and review of the literature

    PubMed Central

    Vergori, Alessandra; Cerase, Alfonso; Migliorini, Lucia; Pluchino, Maria Grazia; Oliveri, Giuseppe; Arrigucci, Umberto; De Luca, Andrea; Montagnani, Francesca

    2015-01-01

    Spinal epidural abscesses (SEAs) are unusual bacterial infections, with possible devastating neurologic sequelae. Despite abundance of case series in adults, reports in children are scanty. We describe a spontaneous SEA due to methicillin susceptible Staphylococcus aureus (MSSA) in a previously healthy 15-year old male, and we perform a literature review regarding management of pediatric SEAs without risk factors, from 2001 to 2014. We found a total of 12 cases (8 males, average age 9.6 years). Clinical presentation was mainly fever, back pain and elevation of inflammation markers. All cases were initially misdiagnosed. Lumbar puncture was performed in 36% of patients. Etiological diagnosis was obtained in 8 cases. MSSA was isolated in 4 patients, methicillin-resistant S. aureus in 1 patient, and S. aureus with unknown susceptibility patterns in 2 cases. The average of therapy duration was 6 weeks. Patients’ spine was always evaluated by gadolinium-enhanced magnetic resonance imaging; most abscesses were localized at thoracic and lumbar area, without osteomyelitis. In 8 cases, laminectomy and/or abscess drainage were performed in association with medical therapy; 3 cases were successfully treated with antimicrobial therapy only; no data were available in one case. A good outcome was obtained in all patients, except a reported residual headache and paraspinal pain lasting for 3 years. The rarity and the possible differential diagnosis can lead to underestimate SEA occurrence in children without risk factors. It seems therefore essential to maintain a high attention to pediatric SEAs. A prompt diagnosis and adequate therapy are essential prognostic factors for remission. PMID:26793474

  5. HIV-1 Vif Versus the APOBEC3 Cytidine Deaminases: An Intracellular Duel Between Pathogen and Host Restriction Factors

    PubMed Central

    Wissing, Silke; Galloway, Nicole L. K.; Greene, Warner C.

    2010-01-01

    The Vif protein of HIV is essential for the effective propagation of this pathogenic retrovirus in vivo. Vif acts by preventing virion encapsidation of two potent antiviral factors, the APOBEC3G and APOBEC3F cytidine deaminases. Decreased encapsidation in part involves Vif-mediated recruitment of a ubiquitin E3 ligase complex that promotes polyubiquitylation and proteasome-mediated degradation of APOBEC3G/F. The resultant decline in intracellular levels of these enzymes leads to decreased encapsidation of APOBECG/F into budding virions. This review discusses recent advances in our understanding of the dynamic interplay of Vif with the antiviral APOBEC3 enzymes. PMID:20538015

  6. HIV-1 Vif versus the APOBEC3 cytidine deaminases: an intracellular duel between pathogen and host restriction factors.

    PubMed

    Wissing, Silke; Galloway, Nicole L K; Greene, Warner C

    2010-10-01

    The Vif protein of HIV is essential for the effective propagation of this pathogenic retrovirus in vivo. Vif acts by preventing virion encapsidation of two potent antiviral factors, the APOBEC3G and APOBEC3F cytidine deaminases. Decreased encapsidation in part involves Vif-mediated recruitment of a ubiquitin E3 ligase complex that promotes polyubiquitylation and proteasome-mediated degradation of APOBEC3G/F. The resultant decline in intracellular levels of these enzymes leads to decreased encapsidation of APOBECG/F into budding virions. This review discusses recent advances in our understanding of the dynamic interplay of Vif with the antiviral APOBEC3 enzymes. PMID:20538015

  7. Inhibition of hepatitis B virus replication by a dNTPase-dependent function of the host restriction factor SAMHD1.

    PubMed

    Jeong, Gi Uk; Park, Il-Hyun; Ahn, Kwangseog; Ahn, Byung-Yoon

    2016-08-01

    SAMHD1 is a cellular protein that possesses dNTPase activity and inhibits retroviruses and DNA viruses through the depletion of cellular dNTPs. However, recent evidence suggests the existence of alternative or additional mechanisms that involve novel nuclease activities. Hepatitis B virus is a DNA virus but resembles retroviruses in that its DNA genome is synthesized via reverse transcription of an RNA transcript. SAMHD1 was shown to inhibit the expression and replication of a transfected HBV DNA. We further investigated the antiviral mechanisms in a newly developed infection assay. Our data indicated that SAMHD1 exerts a profound antiviral effect. In addition, unlike previous findings, our results demonstrate the essential role of SAMHD1 dNTPase. SAMHD1 did not affect virion-derived cccDNA and gene expression but specifically inhibited viral DNA synthesis. These results indicate that SAMHD1 inhibits HBV replication at the reverse transcription step, most likely through the depletion of cellular dNTPs. PMID:27179347

  8. Host and environmental factors defining the epidemiology of type 1 diabetes mellitus in a group of Lebanese children and young adults.

    PubMed

    Zalloua, P A; Terwedow, H; Shbaklo, H; Halaby, G; Xu, X; Azar, S T

    2003-06-01

    The effect of a number of host and environmental factors on the onset of type 1 diabetes mellitus (DM1) in a group of Lebanese children and young adults was studied. Results showed that DM1 in a group of 253 patients presented no gender preference and that the age of onset was similar in both genders. The overall body mass index reflected good metabolic control. HbA1c had a mean value of 8.98%, suggesting poor glucose control. Family history of DM1 and type 2 diabetes mellitus as well as consanguinity in patients' families were not different from those reported in the literature. Finally, onset of DM1 showed seasonal variation, peaking during winter months. DM1 showed a higher prevalence of onset among children born first and a decreased incidence as birth order increased. This study provides valuable data for the diagnosis, control and prevention of DM1 in children. PMID:12880126

  9. Virulence factors in fungal pathogens of man.

    PubMed

    Brunke, Sascha; Mogavero, Selene; Kasper, Lydia; Hube, Bernhard

    2016-08-01

    Human fungal pathogens are a commonly underestimated cause of severe diseases associated with high morbidity and mortality. Like other pathogens, their survival and growth in the host, as well as subsequent host damage, is thought to be mediated by virulence factors which set them apart from harmless microbes. In this review, we describe and discuss commonly employed strategies for fungal survival and growth in the host and how these affect the host-fungus interactions to lead to disease. While many of these strategies require host-specific virulence factors, more generally any fitness factor which allows growth under host-like conditions can be required for pathogenesis. Furthermore, we briefly summarize how different fungal pathogens are thought to damage the host. We find that in addition to a core of common activities relevant for growth, different groups of fungi employ different strategies which in spite of (or together with) the host's response can lead to disease. PMID:27257746

  10. Population differences in host immune factors may influence survival of Gunnison's prairie dogs (Cynomys Gunnisoni) during plague outbreaks

    USGS Publications Warehouse

    Busch, Joseph D.; Van Andel, Roger; Cordova, Jennifer; Colman, Rebecca E.; Keim, Paul; Rocke, Tonie E.; Leid, Jeff G.; Van Pelt, William E.; Wagner, David M.

    2011-01-01

    Over the past 40 yr, epizootics of plague (Yersinia pestis) in northern Arizona have reduced populations of the Gunnison’s prairie dog (Cynomys gunnisoni), with the exception of a large population found in the Aubrey Valley (AV). To examine potential mechanisms accounting for their survival, we collected prairie dog serum samples in 2005–2006 from AV and a neighboring population near Seligman (SE), Arizona. We quantified gene expression at 58 diverse immune proteins using a multiplexed enzyme-linked immunosorbent assay panel. We found a subset of proteins important in coagulation and inflammation (tissue factor [TF], calbindin [Cal], and thrombopoietin [TPO]) and T-cell responses (CD40L and CD40) that were present in AV at levels two to eight times greater than SE. These results suggest that AV and SE animals might differ in their ability to mount an immune response.

  11. Population differences in host immune factors may influence survival of Gunnison's prairie dogs (Cynomys gunnisoni) during plague outbreaks.

    PubMed

    Busch, Joseph D; Van Andel, Roger; Cordova, Jennifer; Colman, Rebecca E; Keim, Paul; Rocke, Tonie E; Leid, Jeff G; Van Pelt, William E; Wagner, David M

    2011-10-01

    Over the past 40 yr, epizootics of plague (Yersinia pestis) in northern Arizona have reduced populations of the Gunnison's prairie dog (Cynomys gunnisoni), with the exception of a large population found in the Aubrey Valley (AV). To examine potential mechanisms accounting for their survival, we collected prairie dog serum samples in 2005-2006 from AV and a neighboring population near Seligman (SE), Arizona. We quantified gene expression at 58 diverse immune proteins using a multiplexed enzyme-linked immunosorbent assay panel. We found a subset of proteins important in coagulation and inflammation (tissue factor [TF], calbindin [Cal], and thrombopoietin [TPO]) and T-cell responses (CD40L and CD40) that were present in AV at levels two to eight times greater than SE. These results suggest that AV and SE animals might differ in their ability to mount an immune response. PMID:22102668

  12. Prognostic Factors on the Graft-versus-Host Disease-Free and Relapse-Free Survival after Adult Allogeneic Hematopoietic Stem Cell Transplantation

    PubMed Central

    Liu, Yao-Chung; Chien, Sheng-Hsuan; Fan, Nai-Wen; Hu, Ming-Hung; Gau, Jyh-Pyng; Liu, Chia-Jen; Yu, Yuan-Bin; Hsiao, Liang-Tsai; Chiou, Tzeon-Jye; Tzeng, Cheng-Hwai; Chen, Po-Min; Liu, Jin-Hwang

    2016-01-01

    The cure of hematologic disorders by allogeneic hematopoietic stem cell transplantation (HSCT) is often associated with major complications resulting in poor outcome, including graft-versus-host disease (GVHD), relapse, and death. A novel composite endpoint of GVHD-free/relapse-free survival (GRFS) in which events include grades 3-4 acute GVHD, chronic GVHD requiring systemic therapy, relapse, or death is censored to completely characterize the survival without mortality or ongoing morbidity. In this regard, studies attempting to identify the prognostic factors of GRFS are quite scarce. Thus, we reviewed 377 adult patients undergoing allogeneic HSCT between 2003 and 2013. The 1- and 2-year GRFS were 40.8% and 36.5%, respectively, significantly worse than overall survival and disease-free survival (log-rank p < 0.001). European Group for Blood and Marrow Transplantation (EBMT) risk score > 2 (p < 0.001) and hematologic malignancy (p = 0.033) were poor prognostic factors for 1-year GRFS. For 2-year GRFS, EBMT risk score > 2 (p < 0.001), being male (p = 0.028), and hematologic malignancy (p = 0.010) were significant for poor outcome. The events between 1-year GRFS and 2-year GRFS predominantly increased in relapsed patients. With prognostic factors of GRFS, we could evaluate the probability of real recovery following HSCT without ongoing morbidity. PMID:27123006

  13. The Symbiosis-Related ERN Transcription Factors Act in Concert to Coordinate Rhizobial Host Root Infection1[OPEN

    PubMed Central

    Cerri, Marion R.; Frances, Lisa; Kelner, Audrey; Middleton, Patrick H.; Auriac, Marie-Christine; Mysore, Kirankumar S.; Erard, Monique; Barker, David G.

    2016-01-01

    Legumes improve their mineral nutrition through nitrogen-fixing root nodule symbioses with soil rhizobia. Rhizobial infection of legumes is regulated by a number of transcription factors, including ERF Required for Nodulation1 (ERN1). Medicago truncatula plants defective in ERN1 are unable to nodulate, but still exhibit early symbiotic responses including rhizobial infection. ERN1 has a close homolog, ERN2, which shows partially overlapping expression patterns. Here we show that ern2 mutants exhibit a later nodulation phenotype than ern1, being able to form nodules but with signs of premature senescence. Molecular characterization of the ern2-1 mutation reveals a key role for a conserved threonine for both DNA binding and transcriptional activity. In contrast to either single mutant, the double ern1-1 ern2-1 line is completely unable to initiate infection or nodule development. The strong ern1-1 ern2-1 phenotype demonstrates functional redundancy between these two transcriptional regulators and reveals the essential role of ERN1/ERN2 to coordinately induce rhizobial infection and nodule organogenesis. While ERN1/ERN2 act in concert in the root epidermis, only ERN1 can efficiently allow the development of mature nodules in the cortex, probably through an independent pathway. Together, these findings reveal the key roles that ERN1/ERN2 play at the very earliest stages of root nodule development. PMID:27208242

  14. A Systematic Analysis of Host Factors Reveals a Med23-Interferon-λ Regulatory Axis against Herpes Simplex Virus Type 1 Replication

    PubMed Central

    Griffiths, Samantha J.; Koegl, Manfred; Boutell, Chris; Zenner, Helen L.; Crump, Colin M.; Pica, Francesca; Gonzalez, Orland; Friedel, Caroline C.; Barry, Gerald; Martin, Kim; Craigon, Marie H.; Chen, Rui; Kaza, Lakshmi N.; Fossum, Even; Fazakerley, John K.; Efstathiou, Stacey; Volpi, Antonio; Zimmer, Ralf; Ghazal, Peter; Haas, Jürgen

    2013-01-01

    Herpes simplex virus type 1 (HSV-1) is a neurotropic virus causing vesicular oral or genital skin lesions, meningitis and other diseases particularly harmful in immunocompromised individuals. To comprehensively investigate the complex interaction between HSV-1 and its host we combined two genome-scale screens for host factors (HFs) involved in virus replication. A yeast two-hybrid screen for protein interactions and a RNA interference (RNAi) screen with a druggable genome small interfering RNA (siRNA) library confirmed existing and identified novel HFs which functionally influence HSV-1 infection. Bioinformatic analyses found the 358 HFs were enriched for several pathways and multi-protein complexes. Of particular interest was the identification of Med23 as a strongly anti-viral component of the largely pro-viral Mediator complex, which links specific transcription factors to RNA polymerase II. The anti-viral effect of Med23 on HSV-1 replication was confirmed in gain-of-function gene overexpression experiments, and this inhibitory effect was specific to HSV-1, as a range of other viruses including Vaccinia virus and Semliki Forest virus were unaffected by Med23 depletion. We found Med23 significantly upregulated expression of the type III interferon family (IFN-λ) at the mRNA and protein level by directly interacting with the transcription factor IRF7. The synergistic effect of Med23 and IRF7 on IFN-λ induction suggests this is the major transcription factor for IFN-λ expression. Genotypic analysis of patients suffering recurrent orofacial HSV-1 outbreaks, previously shown to be deficient in IFN-λ secretion, found a significant correlation with a single nucleotide polymorphism in the IFN-λ3 (IL28b) promoter strongly linked to Hepatitis C disease and treatment outcome. This paper describes a link between Med23 and IFN-λ, provides evidence for the crucial role of IFN-λ in HSV-1 immune control, and highlights the power of integrative genome-scale approaches to

  15. Selective factors associated with the evolution of codon usage in natural populations of arboviruses and their practical application to infer possible hosts for emerging viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Arboviruses (arthropod borne viruses) have life cycles that include both vertebrate and invertebrate hosts with substantial differences in vector and host specificity between different viruses. Most arboviruses utilize RNA for their genetic material and are completely dependent on host tRNAs for the...

  16. Influence of Mortality Factors and Host Resistance on the Population Dynamics of Emerald Ash Borer (Coleoptera: Buprestidae) in Urban Forests.

    PubMed

    Macquarrie, Chris J K; Scharbach, Roger

    2015-02-01

    The success of emerald ash borer (Agrilus planipennis Fairmaire) in North America is hypothesized to be due to both the lack of significant natural enemies permitting easy establishment and a population of trees that lack the ability to defend themselves, which allows populations to grow unchecked. Since its discovery in 2002, a number of studies have examined mortality factors of the insect in forests, but none have examined the role of natural enemies and other mortality agents in the urban forest. This is significant because it is in the urban forest where the emerald ash borer has had the most significant economic impacts. We studied populations in urban forests in three municipalities in Ontario, Canada, between 2010 and 2012 using life tables and stage-specific survivorship to analyze data from a split-rearing manipulative experiment. We found that there was little overall mortality caused by natural enemies; most mortality we did observe was caused by disease. Stage-specific survivorship was lowest in small and large larvae, supporting previous observations of high mortality in these two stages. We also used our data to test the hypothesis that mortality and density in emerald ash borer are linked. Our results support the prediction of a negative relationship between mortality and density. However, the relationship varies between insects developing in the crown and those in the trunk of the tree. This relationship was significant because when incorporated with previous findings, it suggests a mechanism and hypothesis to explain the outbreak dynamics of the emerald ash borer. PMID:26308819

  17. Molecular expression and characterization of a homologue of host cytokine macrophage migration inhibitory factor from Trichinella spp.

    PubMed

    Wu, Z; Boonmars, T; Nagano, I; Nakada, T; Takahashi, Y

    2003-06-01

    A homologue of cytokine macrophage migration inhibitory factor (MIF) from complementary DNA (cDNA) of Trichinella spiralis and Trichinella pseudospiralis was expressed in Escherichia coli and characterized. The sequence analysis indicated that the predicted amino acid sequence has an identity of 57 and 44% with the MIF of nematodes Trichuris trichiura and Brugia malayi respectively, and 41 and 40% with that of a human and a mouse, respectively. The identity in sequences of cDNA and amino acids between T. spiralis and T. pseudospiralis was 91 and 86%, respectively. Western blot analysis showed that anti-MIF antibodies positively stained proteins from the extracts of adult worms or muscle larvae migrating at about 12.5 kDa (3 isoforms with isoelectric point 5.23, 5.72, and 6.29). Semiquantitative reverse transcriptase-polymerase chain reaction revealed that the gene was expressed in various developmental stages, including in adult worms, newborn larvae, precyst muscle larvae, and postcyst muscle larvae, although there was difference in the expression level among these stages. The immunohistochemical analysis showed the MIF exists in the muscle cells of the body wall and some stichocytes of larvae. Histopathology of T. spiralis-infected muscles revealed an accumulation of mononuclear cells around the worms, and immunocytochemical staining showed these cells were not macrophages. Mononuclear cells, including macrophages, were, however, observed in cardiac muscles where the parasite did not encyst. Macrophages accumulated around the Sephadex beads transplanted in mice subcutaneously, but this accumulation was profoundly inhibited when the beads were pretreated with MIF recombinant protein. PMID:12880250

  18. An Additional Potential Factor for Kidney Stone Formation during Space Flights: Calcifying Nanoparticles (Nanobacteria): A Case Report

    NASA Technical Reports Server (NTRS)

    Jones, Jeffrey A.; Ciftcioglu, Neva; Schmid, Joseph; Griffith, Donald

    2007-01-01

    Spaceflight-induced microgravity appears to be a risk factor for the development of urinary calculi due to skeletal calcium liberation and other undefined factors, resulting in stone disease in crewmembers during and after spaceflight. Calcifying nanoparticles, or nanobacteria, reproduce at a more rapid rate in simulated microgravity conditions and create external shells of calcium phosphate in the form of apatite. The questions arises whether calcifying nanoparticles are niduses for calculi and contribute to the development of clinical stone disease in humans, who possess environmental factors predisposing to the development of urinary calculi and potentially impaired immunological defenses during spaceflight. A case of a urinary calculus passed from an astronaut post-flight with morphological characteristics of calcifying nanoparticles and staining positive for a calcifying nanoparticle unique antigen, is presented.

  19. Dispersal of a defensive symbiont depends on contact between hosts, host health, and host size.

    PubMed

    Hopkins, Skylar R; Boyle, Lindsey J; Belden, Lisa K; Wojdak, Jeremy M

    2015-10-01

    Symbiont dispersal is necessary for the maintenance of defense mutualisms in space and time, and the distribution of symbionts among hosts should be intricately tied to symbiont dispersal behaviors. However, we know surprisingly little about how most defensive symbionts find and choose advantageous hosts or what cues trigger symbionts to disperse from their current hosts. In a series of six experiments, we explored the dispersal ecology of an oligochaete worm (Chaetogaster limnaei) that protects snail hosts from infection by larval trematode parasites. Specifically, we determined the factors that affected net symbiont dispersal from a current "donor" host to a new "receiver" host. Symbionts rarely dispersed unless hosts directly came in contact with one another. However, symbionts overcame their reluctance to disperse across the open environment if the donor host died. When hosts came in direct contact, net symbiont dispersal varied with both host size and trematode infection status, whereas symbiont density did not influence the probability of symbiont dispersal. Together, these experiments show that symbiont dispersal is not a constant, random process, as is often assumed in symbiont dispersal models, but rather the probability of dispersal varies with ecological conditions and among individual hosts. The observed heterogeneity in dispersal rates among hosts may help to explain symbiont aggregation among snail hosts in nature. PMID:25964062

  20. Employing Lead Thiocyanate Additive to Reduce the Hysteresis and Boost the Fill Factor of Planar Perovskite Solar Cells.

    PubMed

    Ke, Weijun; Xiao, Chuanxiao; Wang, Changlei; Saparov, Bayrammurad; Duan, Hsin-Sheng; Zhao, Dewei; Xiao, Zewen; Schulz, Philip; Harvey, Steven P; Liao, Weiqiang; Meng, Weiwei; Yu, Yue; Cimaroli, Alexander J; Jiang, Chun-Sheng; Zhu, Kai; Al-Jassim, Mowafak; Fang, Guojia; Mitzi, David B; Yan, Yanfa

    2016-07-01

    Lead thiocyanate in the perovskite precursor can increase the grain size of a perovskite thin film and reduce the conductivity of the grain boundaries, leading to perovskite solar cells with reduced hysteresis and enhanced fill factor. A planar perovskite solar cell with grain boundary and interface passivation achieves a steady-state efficiency of 18.42%. PMID:27145346

  1. Host cell factor-1 recruitment to E2F-bound and cell-cycle-control genes is mediated by THAP11 and ZNF143.

    PubMed

    Parker, J Brandon; Yin, Hanwei; Vinckevicius, Aurimas; Chakravarti, Debabrata

    2014-11-01

    Host cell factor-1 (HCF-1) is a metazoan transcriptional coregulator essential for cell-cycle progression and cell proliferation. Current models suggest a mechanism whereby HCF-1 functions as a direct coregulator of E2F proteins, facilitating the expression of genes necessary for cell proliferation. In this report, we show that HCF-1 recruitment to numerous E2F-bound promoters is mediated by the concerted action of zinc finger transcription factors THAP11 and ZNF143, rather than E2F proteins directly. THAP11, ZNF143, and HCF-1 form a mutually dependent complex on chromatin, which is independent of E2F occupancy. Disruption of the THAP11/ZNF143/HCF-1 complex results in altered expression of cell-cycle control genes and leads to reduced cell proliferation, cell-cycle progression, and cell viability. These data establish a model in which a THAP11/ZNF143/HCF-1 complex is a critical component of the transcriptional regulatory network governing cell proliferation. PMID:25437553

  2. Host Cell Factor-1 Recruitment to E2F-bound and Cell Cycle Control Genes is Mediated by THAP11 and ZNF143

    PubMed Central

    Parker, J. Brandon; Yin, Hanwei; Vinckevicius, Aurimas; Chakravarti, Debabrata

    2014-01-01

    Summary Host cell factor-1 (HCF-1) is a metazoan transcriptional co-regulator essential for cell cycle progression and cell proliferation. Current models suggest a mechanism whereby HCF-1 functions as a direct co-regulator of E2F proteins, facilitating the expression of genes necessary for cell proliferation. In this report, we show that HCF-1 recruitment to numerous E2F-bound promoters is mediated by the concerted action of zinc finger transcription factors THAP11 and ZNF143, rather than E2F proteins directly. THAP11, ZNF143, and HCF-1 form a mutually dependent complex on chromatin, which is independent of E2F occupancy. Disruption of the THAP11/ZNF143/HCF-1 complex results in altered expression of cell cycle control genes and leads to reduced cell proliferation, cell cycle progression, and cell viability. These data establish a new model which suggests that a THAP11/ZNF143/HCF-1 complex is a critical component of the transcriptional regulatory network governing cell proliferation. PMID:25437553

  3. A Host KH RNA-Binding Protein Is a Susceptibility Factor Targeted by an RXLR Effector to Promote Late Blight Disease☆

    PubMed Central

    Wang, Xiaodan; Boevink, Petra; McLellan, Hazel; Armstrong, Miles; Bukharova, Tatyana; Qin, Zhiwei; Birch, Paul R.J.

    2015-01-01

    Plant pathogens deliver effector proteins that alter host processes to create an environment conducive to colonization. Attention has focused on identifying the targets of effectors and how their manipulation facilitates disease. RXLR effector Pi04089 from the potato blight pathogen Phytophthora infestans accumulates in the host nucleus and enhances colonization when transiently expressed in planta. Its nuclear localization is required for enhanced P. infestans colonization. Pi04089 interacts in yeast and in planta with a putative potato K-homology (KH) RNA-binding protein, StKRBP1. Co-localization of Pi04089 and StKRBP1, and bimolecular fluorescence complementation between them, indicate they associate at nuclear speckles. StKRBP1 protein levels increased when it was co-expressed with Pi04089. Indeed, such accumulation of StKRBP1 was observed also on the first day of leaf colonization by the pathogen. Remarkably, overexpression of StKRBP1 significantly enhances P. infestans infection. Mutation of the nucleotide-binding motif GxxG to GDDG in all three KH domains of StKRBP1 abolishes its interaction with Pi04089, its localization to nuclear speckles, and its increased accumulation when co-expressed with the effector. Moreover, the mutant StKRBP1 protein no longer enhances leaf colonization by P. infestans, implying that nucleotide binding is likely required for this activity. We thus argue that StKRBP1 can be regarded as a susceptibility factor, as its activity is beneficial to the pathogen. PMID:25936676

  4. Integration Host Factor (IHF) binds to the promoter region of the phtD operon involved in phaseolotoxin synthesis in P. syringae pv. phaseolicola NPS3121

    PubMed Central

    2011-01-01

    Background Pseudomonas syringae pv. phaseolicola, the causal agent of halo blight disease in beans, produces a toxin known as phaseolotoxin, in whose synthesis participate a group of genes organized within the genome in a region known as the "Pht cluster". This region, which is thought to have been acquired by horizontal gene transfer, includes 5 transcriptional units, two monocistronic (argK, phtL) and three polycistronic (phtA, phtD, phtM), whose expression is temperature dependent. So far, the regulatory mechanisms involved in phaseolotoxin synthesis have not been elucidated and the only well-established fact is the requirement of low temperatures for its synthesis. In this work, we searched for regulatory proteins that could be involved in phaseolotoxin synthesis, focusing on the regulation of the phtD operon. Results In this study we identified the global regulator IHF (Integration Host Factor), which binds to the promoter region of the phtD operon, exerting a negative effect on the expression of this operon. This is the first regulatory protein identified as part of the phaseolotoxin synthesis system. Our findings suggest that the Pht cluster was similarly regulated in the ancestral cluster by IHF or similar protein, and integrated into the global regulatory mechanism of P. syringae pv. phaseolicola, after the horizontal gene transfer event by using the host IHF protein. Conclusion This study identifies the IHF protein as one element involved in the regulation of phaseolotoxin synthesis in P. syringae pv. phaseolicola NPS3121 and provides new insights into the regulatory mechanisms involved in phaseolotoxin production. PMID:21542933

  5. Overexpression of hepatocyte growth factor in SBMA model mice has an additive effect on combination therapy with castration.

    PubMed

    Ding, Ying; Adachi, Hiroaki; Katsuno, Masahisa; Huang, Zhe; Jiang, Yue-Mei; Kondo, Naohide; Iida, Madoka; Tohnai, Genki; Nakatsuji, Hideaki; Funakoshi, Hiroshi; Nakamura, Toshikazu; Sobue, Gen

    2015-12-25

    Spinal and bulbar muscular atrophy (SBMA) is an inherited motor neuron disease caused by the expansion of a polyglutamine (polyQ)-encoding tract within the androgen receptor (AR) gene. The pathologic features of SBMA are motor neuron loss in the spinal cord and brainstem and diffuse nuclear accumulation and nuclear inclusions of mutant AR in residual motor neurons and certain visceral organs. Hepatocyte growth factor (HGF) is a polypeptide growth factor which has neuroprotective properties. To investigate whether HGF overexpression can affect disease progression in a mouse model of SBMA, we crossed SBMA transgenic model mice expressing an AR gene with an expanded CAG repeat with mice overexpressing HGF. Here, we report that high expression of HGF induces Akt phosphorylation and modestly ameliorated motor symptoms in an SBMA transgenic mouse model treated with or without castration. These findings suggest that HGF overexpression can provide a potential therapeutic avenue as a combination therapy with disease-modifying therapies in SBMA. PMID:26551462

  6. Smoking and polymorphisms in xenobiotic metabolism and DNA repair genes are additive risk factors affecting bladder cancer in Northern Tunisia.

    PubMed

    Rouissi, Kamel; Ouerhani, Slah; Hamrita, Bechr; Bougatef, Karim; Marrakchi, Raja; Cherif, Mohamed; Ben Slama, Mohamed Riadh; Bouzouita, Mohamed; Chebil, Mohamed; Ben Ammar Elgaaied, Amel

    2011-12-01

    Cancer epidemiology has undergone marked development since the nineteen-fifties. One of the most spectacular and specific contributions was the demonstration of the massive effect of smoking and genetic polymorphisms on the occurrence of bladder cancer. The tobacco carcinogens are metabolized by various xenobiotic metabolizing enzymes, such as the super-families of N-acetyltransferases (NAT) and glutathione S-transferases (GST). DNA repair is essential to an individual's ability to respond to damage caused by tobacco carcinogens. Alterations in DNA repair genes may affect cancer risk by influencing individual susceptibility to this environmental exposure. Polymorphisms in NAT2, GST and DNA repair genes alter the ability of these enzymes to metabolize carcinogens or to repair alterations caused by this process. We have conducted a case-control study to assess the role of smoking, slow NAT2 variants, GSTM1 and GSTT1 null, and XPC, XPD, XPG nucleotide excision-repair (NER) genotypes in bladder cancer development in North Tunisia. Taken alone, each gene unless NAT2 did not appear to be a factor affecting bladder cancer susceptibility. For the NAT2 slow acetylator genotypes, the NAT2*5/*7 diplotype was found to have a 7-fold increased risk to develop bladder cancer (OR = 7.14; 95% CI: 1.30-51.41). However, in tobacco consumers, we have shown that Null GSTM1, Wild GSTT1, Slow NAT2, XPC (CC) and XPG (CC) are genetic risk factors for the disease. When combined together in susceptible individuals compared to protected individuals these risk factors give an elevated OR (OR = 61). So, we have shown a strong cumulative effect of tobacco and different combinations of studied genetic risk factors which lead to a great susceptibility to bladder cancer. PMID:21647780

  7. Risk Factors for Acute Graft-Versus-Host Disease After Human Leukocyte Antigen–Identical Sibling Transplants for Adults With Leukemia

    PubMed Central

    Hahn, Theresa; McCarthy, Philip L.; Zhang, Mei-Jie; Wang, Dan; Arora, Mukta; Frangoul, Haydar; Gale, Robert Peter; Hale, Gregory A.; Horan, John; Isola, Luis; Maziarz, Richard T.; van Rood, Jon J.; Gupta, Vikas; Halter, Joerg; Reddy, Vijay; Tiberghien, Pierre; Litzow, Mark; Anasetti, Claudio; Pavletic, Stephen; Ringdén, Olle

    2008-01-01

    Purpose Acute graft-versus-host disease (GVHD) causes substantial morbidity and mortality after human leukocyte antigen (HLA)-identical sibling transplants. No large registry studies of acute GVHD risk factors have been reported in two decades. Risk factors may have changed in this interval as transplant-related techniques have evolved. Patients and Methods Acute GVHD risk factors were analyzed in 1,960 adults after HLA-identical sibling myeloablative transplant for acute myeloid leukemia (AML), acute lymphocytic leukemia (ALL), or chronic myeloid leukemia (CML) reported by 226 centers worldwide to the Center for International Blood and Marrow Transplant Research from 1995 to 2002. Outcome was measured as time from transplant to onset of grade 2 to 4 acute GVHD, with death without acute GVHD as a competing risk. Results Cumulative incidence of grade 2 to 4 acute GVHD was 35% (95% CI, 33% to 37%). In multivariable analyses, factors significantly associated with grade 2 to 4 acute GVHD were cyclophosphamide + total-body irradiation versus busulfan + cyclophosphamide (relative risk [RR] = 1.4; P < .0001), blood cell versus bone marrow grafts in patients age 18 to 39 years (RR = 1.43; P = .0023), recipient age 40 and older versus age 18 to 39 years receiving bone marrow grafts (RR = 1.44; P = .0005), CML versus AML/ALL (RR = 1.35; P = .0003), white/Black versus Asian/Hispanic race (RR = 1.54; P = .0003), Karnofsky performance score less than 90 versus 90 to 100 (RR = 1.27; P = .014), and recipient/donor cytomegalovirus-seronegative versus either positive (RR = 1.20; P = .04). Stratification by disease showed the same significant predictors of grade 2 to 4 acute GVHD for CML; however, KPS and cytomegalovirus serostatus were not significant predictors for AML/ALL. Conclusion This analysis confirmed several previously reported risk factors for grade 2 to 4 acute GVHD. However, several new factors were identified whereas others are no longer significant. These new data may

  8. Food additives.

    PubMed

    Berglund, F

    1978-01-01

    The use of additives to food fulfils many purposes, as shown by the index issued by the Codex Committee on Food Additives: Acids, bases and salts; Preservatives, Antioxidants and antioxidant synergists; Anticaking agents; Colours; Emulfifiers; Thickening agents; Flour-treatment agents; Extraction solvents; Carrier solvents; Flavours (synthetic); Flavour enhancers; Non-nutritive sweeteners; Processing aids; Enzyme preparations. Many additives occur naturally in foods, but this does not exclude toxicity at higher levels. Some food additives are nutrients, or even essential nutritents, e.g. NaCl. Examples are known of food additives causing toxicity in man even when used according to regulations, e.g. cobalt in beer. In other instances, poisoning has been due to carry-over, e.g. by nitrate in cheese whey - when used for artificial feed for infants. Poisonings also occur as the result of the permitted substance being added at too high levels, by accident or carelessness, e.g. nitrite in fish. Finally, there are examples of hypersensitivity to food additives, e.g. to tartrazine and other food colours. The toxicological evaluation, based on animal feeding studies, may be complicated by impurities, e.g. orthotoluene-sulfonamide in saccharin; by transformation or disappearance of the additive in food processing in storage, e.g. bisulfite in raisins; by reaction products with food constituents, e.g. formation of ethylurethane from diethyl pyrocarbonate; by metabolic transformation products, e.g. formation in the gut of cyclohexylamine from cyclamate. Metabolic end products may differ in experimental animals and in man: guanylic acid and inosinic acid are metabolized to allantoin in the rat but to uric acid in man. The magnitude of the safety margin in man of the Acceptable Daily Intake (ADI) is not identical to the "safety factor" used when calculating the ADI. The symptoms of Chinese Restaurant Syndrome, although not hazardous, furthermore illustrate that the whole ADI

  9. Breeding site selection by coho salmon (Oncorhynchus kisutch) in relation to large wood additions and factors that influence reproductive success

    USGS Publications Warehouse

    Clark, Steven M.; Dunham, Jason B.; McEnroe, Jeffery R.; Lightcap, Scott W.

    2014-01-01

    The fitness of female Pacific salmon (Oncorhynchus spp.) with respect to breeding behavior can be partitioned into at least four fitness components: survival to reproduction, competition for breeding sites, success of egg incubation, and suitability of the local environment near breeding sites for early rearing of juveniles. We evaluated the relative influences of habitat features linked to these fitness components with respect to selection of breeding sites by coho salmon (Oncorhynchus kisutch). We also evaluated associations between breeding site selection and additions of large wood, as the latter were introduced into the study system as a means of restoring habitat conditions to benefit coho salmon. We used a model selection approach to organize specific habitat features into groupings reflecting fitness components and influences of large wood. Results of this work suggest that female coho salmon likely select breeding sites based on a wide range of habitat features linked to all four hypothesized fitness components. More specifically, model parameter estimates indicated that breeding site selection was most strongly influenced by proximity to pool-tail crests and deeper water (mean and maximum depths). Linkages between large wood and breeding site selection were less clear. Overall, our findings suggest that breeding site selection by coho salmon is influenced by a suite of fitness components in addition to the egg incubation environment, which has been the emphasis of much work in the past.

  10. Comparing mechanisms of host manipulation across host and parasite taxa

    USGS Publications Warehouse

    Lafferty, Kevin D.; Shaw, Jenny C.

    2013-01-01

    Parasites affect host behavior in several ways. They can alter activity, microhabitats or both. For trophically transmitted parasites (the focus of our study), decreased activity might impair the ability of hosts to respond to final-host predators, and increased activity and altered microhabitat choice might increase contact rates between hosts and final-host predators. In an analysis of trophically transmitted parasites, more parasite groups altered activity than altered microhabitat choice. Parasites that infected vertebrates were more likely to impair the host’s reaction to predators, whereas parasites that infected invertebrates were more likely to increase the host’s contact with predators. The site of infection might affect how parasites manipulate their hosts. For instance, parasites in the central nervous system seem particularly suited to manipulating host behavior. Manipulative parasites commonly occupy the body cavity, muscles and central nervous systems of their hosts. Acanthocephalans in the data set differed from other taxa in that they occurred exclusively in the body cavity of invertebrates. In addition, they were more likely to alter microhabitat choice than activity. Parasites in the body cavity (across parasite types) were more likely to be associated with increased host contact with predators. Parasites can manipulate the host through energetic drain, but most parasites use more sophisticated means. For instance, parasites target four physiological systems that shape behavior in both invertebrates and vertebrates: neural, endocrine, neuromodulatory and immunomodulatory. The interconnections between these systems make it difficult to isolate specific mechanisms of host behavioral manipulation.

  11. Fungal sensing of host environment.

    PubMed

    Braunsdorf, C; Mailänder-Sánchez, D; Schaller, M

    2016-09-01

    To survive inside a host, fungi have to adapt to a changing and often hostile environment and therefore need the ability to recognize what is going on around them. To adapt to different host niches, they need to sense external conditions such as temperature, pH and to recognize specific host factors. The ability to respond to physiological changes inside the host, independent of being in a commensal, pathogenic or even symbiotic context, implicates mechanisms for sensing of specific host factors. Because the cell wall is constantly in contact with the surrounding, fungi express receptors on the surface of their cell wall, such as pheromone receptors, which have important roles, besides mediating chemotropism for mating. We are not restricting the discussion to the human host because the receptors and mechanisms used by different fungal species to sense their environment are often similar even for plant pathogens. Furthermore, the natural habitat of opportunistic pathogenic fungi with the potential to cause infection in a human host is in soil and on plants. While the hosts' mechanisms of sensing fungal pathogens have been addressed in the literature, the focus of this review is to fill the gap, giving an overview on fungal sensing of a host-(ile) environment. Expanding our knowledge on host-fungal interactions is extremely important to prevent and treat diseases of pathogenic fungi, which are important issues in human health and agriculture but also to understand the delicate balance of fungal symbionts in our ecosystem. PMID:27155351

  12. Escherichia coli integration host factor bends the DNA at the ends of IS1 and in an insertion hotspot with multiple IHF binding sites.

    PubMed Central

    Prentki, P; Chandler, M; Galas, D J

    1987-01-01

    The integration host factor of Escherichia coli (IHF) is a small, histone-like protein which participates in the integration of bacteriophage lambda into the E. coli chromosome and in a number of regulatory processes. Our recent footprinting analysis has shown that IHF binds specifically to the ends of the transposable element IS1, as well as to several sites within a short segment of the plasmid pBR322. We have extended our studies of the binding of the IHF molecule to these sites in vitro using a gel retardation assay. We report here that IHF bends the DNA upon binding, as judged from the strong cyclic dependence of the protein-induced mobility shift on the position of the binding site. Using cloned, synthetic ends of IS1 as substrates, we have found that some mutations within the conserved bases of the IHF consensus binding sequence abolish binding, and that alterations of the flanking sequences can greatly reduce IHF binding. The presence of multiple IHF sites on a single DNA fragment increases binding very little, indicating that IHF does not bind cooperatively in this complex. We discuss the possibility that DNA bending is related to the role IHF plays in forming and stabilizing nucleoprotein complexes, and suggest that bending at the IHF sites may be important to its diverse effects in the cell. Images Fig. 3. Fig. 4. Fig. 5. PMID:2822395

  13. Autogenous Translational Regulation of the Borna Disease Virus Negative Control Factor X from Polycistronic mRNA Using Host RNA Helicases

    PubMed Central

    Watanabe, Yohei; Ohtaki, Naohiro; Hayashi, Yohei; Ikuta, Kazuyoshi; Tomonaga, Keizo

    2009-01-01

    Borna disease virus (BDV) is a nonsegmented, negative-strand RNA virus that employs several unique strategies for gene expression. The shortest transcript of BDV, X/P mRNA, encodes at least three open reading frames (ORFs): upstream ORF (uORF), X, and P in the 5′ to 3′ direction. The X is a negative regulator of viral polymerase activity, while the P phosphoprotein is a necessary cofactor of the polymerase complex, suggesting that the translation of X is controlled rigorously, depending on viral replication. However, the translation mechanism used by the X/P polycistronic mRNA has not been determined in detail. Here we demonstrate that the X/P mRNA autogenously regulates the translation of X via interaction with host factors. Transient transfection of cDNA clones corresponding to the X/P mRNA revealed that the X ORF is translated predominantly by uORF-termination-coupled reinitiation, the efficiency of which is upregulated by expression of P. We found that P may enhance ribosomal reinitiation at the X ORF by inhibition of the interaction of the DEAD-box RNA helicase DDX21 with the 5′ untranslated region of X/P mRNA, via interference with its phosphorylation. Our results not only demonstrate a unique translational control of viral regulatory protein, but also elucidate a previously unknown mechanism of regulation of polycistronic mRNA translation using RNA helicases. PMID:19893625

  14. Anthracycline inhibits recruitment of hypoxia-inducible transcription factors and suppresses tumor cell migration and cardiac angiogenic response in the host.

    PubMed

    Tanaka, Tetsuhiro; Yamaguchi, Junna; Shoji, Kumi; Nangaku, Masaomi

    2012-10-12

    Anthracycline chemotherapeutic agents of the topoisomerase inhibitor family are widely used for the treatment of various tumors. Although targeted tumor tissues are generally situated in a hypoxic environment, the connection between efficacy of anthracycline agents and cellular hypoxia response has not been investigated in depth. Here, we report that doxorubicin (DXR) impairs the transcriptional response of the hypoxia-inducible factor (HIF) by inhibiting the binding of the HIF heterodimer to the consensus -RCGTG- enhancer element. This pleiotropic effect retarded migration of von Hippel-Lindau (VHL)-defective renal cell carcinoma and that of VHL-competent renal cell carcinoma in hypoxia. This effect was accompanied by a coordinated down-regulation of HIF target lysyl oxidase (LOX) family members LOX, LOX-like2 (LOXL2), and LOXL4. Furthermore, DXR suppressed HIF target genes in tumor xenografts, inhibited cardiac induction of HIF targets in rats with acute anemia, and impaired the angiogenic response in the isoproterenol-induced heart failure model, which may account for the clinical fragility of doxorubicin cardiomyopathy. Collectively, these findings highlight the impaired hypoxia response by anthracycline agents affecting both tumors and organs of the cancer host and offer a promising opportunity to develop HIF inhibitors using DXR as a chemical template. PMID:22908232

  15. Host translation shutoff mediated by non-structural protein 2 is a critical factor in the antiviral state resistance of Venezuelan equine encephalitis virus.

    PubMed

    Bhalla, Nishank; Sun, Chengqun; Metthew Lam, L K; Gardner, Christina L; Ryman, Kate D; Klimstra, William B

    2016-09-01

    Most previous studies of interferon-alpha/beta (IFN-α/β) response antagonism by alphaviruses have focused upon interruption of IFN-α/β induction and/or receptor signaling cascades. Infection of mice with Venezuelan equine encephalitis alphavirus (VEEV) or Sindbis virus (SINV) induces serum IFN-α/β, that elicits a systemic antiviral state in uninfected cells successfully controlling SINV but not VEEV replication. Furthermore, VEEV replication is more resistant than that of SINV to a pre-existing antiviral state in vitro. While host macromolecular shutoff is proposed as a major antagonist of IFN-α/β induction, the underlying mechanisms of alphavirus resistance to a pre-existing antiviral state are not fully defined, nor is the mechanism for the greater resistance of VEEV. Here, we have separated viral transcription and translation shutoff with multiple alphaviruses, identified the viral proteins that induce each activity, and demonstrated that VEEV nonstructural protein 2-induced translation shutoff is likely a critical factor in enhanced antiviral state resistance of this alphavirus. PMID:27318152

  16. Role of Granulocyte Macrophage Colony-Stimulating Factor in Host Defense Against Pulmonary Cryptococcus neoformans Infection during Murine Allergic Bronchopulmonary Mycosis

    PubMed Central

    Chen, Gwo-Hsiao; Olszewski, Michal A.; McDonald, Roderick A.; Wells, Jason C.; Paine, Robert; Huffnagle, Gary B.; Toews, Galen B.

    2007-01-01

    We investigated the role of granulocyte macrophage colony-stimulating factor (GM-CSF) in host defense in a murine model of pulmonary cryptococcosis induced by intratracheal inoculation of Cryptococcus neoformans. Pulmonary C. neoformans infection of C57BL/6 mice is an established model of an allergic bronchopulmonary mycosis. Our objective was to determine whether GM-CSF regulates the pulmonary Th2 immune response in C. neoformans-infected C57BL/6 mice. Long-term pulmonary fungistasis was lost in GM-CSF knockout (GM−/−) mice, resulting in increased pulmonary burden of fungi between weeks 3 and 5. GM-CSF was required for the early influx of macrophages and CD4 and CD8 T cells into the lungs but was not required later in the infection. Lack of GM-CSF also resulted in reduced eosinophil recruitment and delayed recruitment of mononuclear cells into the airspace. Macrophages from GM+/+ mice showed numerous hallmarks of alternatively activated macrophages: higher numbers of intracellular cryptococci, YM1 crystals, and induction of CCL17. These hallmarks are absent in macrophages from GM−/− mice. Mucus-producing goblet cells were abundantly present within the bronchial epithelial layer in GM+/+ mice but not in GM−/− mice at week 5 after infection. Production of both Th1 and Th2 cytokines was impaired in the absence of GM-CSF, consistent with both reduced C. neoformans clearance and absence of allergic lung pathology. PMID:17322386

  17. Characterization and Risk Factor Analysis of Osteoporosis in a Large Cohort of Patients with Chronic Graft-versus-Host Disease.

    PubMed

    Pirsl, Filip; Curtis, Lauren M; Steinberg, Seth M; Tella, Sri Harsha; Katić, Mašenjka; Dobbin, Marnie; Hsu, Jennifer; Hakim, Fran T; Mays, Jacqueline W; Im, Annie P; Pulanić, Dražen; Mitchell, Sandra A; Baruffaldi, Judy; Masuch, Licia; Halverson, David C; Gress, Ronald E; Barsony, Julianna; Pavletic, Steven Z

    2016-08-01

    The National Institutes of Health Chronic Graft-versus-Host Disease (cGVHD) Consensus Project Ancillary and Supportive Care Guidelines recommend annual assessment of bone mineral density (BMD) to monitor bone health. The study of osteoporosis in patients with cGVHD has been limited to small numbers of patients, and the guidelines are based on experience with other chronic diseases and expert opinion. We hypothesized that the prevalence of osteoporosis is high in a cohort of 258 patients with moderate to severe cGVHD because of prolonged exposure to risk factors for osteoporosis after allogeneic hematopoietic stem cell transplantation. We defined osteoporosis using BMD criteria (T-score ≤-2.5) at 3 anatomic sites-the femoral neck (FN), lumbar spine (LS), and total hip (TH)-and characterized risk factors through univariate and multivariate analyses. We found that low body weight (FN, P < .0001; LS, P = .0002; TH, P < .0001), malnutrition (FN, P = .0002; LS, P = .03; TH, P = .0076), higher platelet count (FN, P = .0065; TH, P = .0025), higher average National Institutes of Health organ score (FN, P = .038), higher prednisone dose (LS, P = .032), lower complement component 3 (LS, P = .0073), and physical inactivity (FN, P = .01) were associated with osteoporosis in at least 1 site. T-scores were significantly lower in the FN compared with the LS or TH (P < .0001 for both). The prevalence of osteoporosis and osteopenia was high (17% and 60%, respectively), supporting current recommendations for frequent monitoring of BMD. The association of higher platelet count in patients with cGVHD and osteoporosis has not been reported previously and represents a new area of interest in the study of osteoporosis after allogeneic hematopoietic stem cell transplantation. PMID:27118572

  18. Host immune gene polymorphisms in combination with clinical and demographic factors predict late survival in diffuse large B-cell lymphoma patients in the pre-rituximab era

    PubMed Central

    Habermann, Thomas M.; Wang, Sophia S.; Maurer, Matthew J.; Morton, Lindsay M.; Lynch, Charles F.; Ansell, Stephen M.; Hartge, Patricia; Severson, Richard K.; Rothman, Nathaniel; Davis, Scott; Geyer, Susan M.; Cozen, Wendy; Chanock, Stephen J.

    2008-01-01

    To evaluate the hypothesis that host germ line variation in immune genes is associated with overall survival in diffuse large B-cell lymphoma (DLBCL), we genotyped 73 single nucleotide polymorphisms (SNPs) from 44 candidate genes in 365 DLBCL patients diagnosed from 1998 to 2000. We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for the association of SNPs with survival after adjusting for clinical factors. During follow-up, 96 (26%) patients died, and the median follow-up was 57 months for surviving patients. The observed survival of this cohort was consistent with population-based estimates conditioned on surviving 12 months. An IL10 haplotype (global P = .03) and SNPs in IL8RB (rs1126580; HRAG/GG = 2.11; CI, 1.28-3.50), IL1A (rs1800587; HRCT/TT = 1.90; CI, 1.26-2.87), TNF (rs1800629; HRAG/GG = 1.44; CI, 0.95-2.18), and IL4R (rs2107356; HRCC/CT = 1.97; CI, 1.01-3.83) were the strongest predictors of overall survival. A risk score that combined the latter 4 SNPs with clinical factors was strongly associated with survival in a Cox model (P = 6.0 × 10−11). Kaplan-Meier 5-year survival estimates for low, intermediate-low, intermediate-high, and high-risk patients were 94%, 79%, 60%, and 48%, respectively. These data support a role for germ line variation in immune genes, particularly genes associated with a proinflammatory state, as predictors of late survival in DLBCL. PMID:18633131

  19. Host, vehicular and environmental factors responsible for road traffic crashes in a nigerian city: identifiable issues for road traffic injury control

    PubMed Central

    Adeoye, Peter Oladapo; Kadri, Dotun Musiliu; Bello, Jibril Oyekunle; Ofoegbu, Chima Kingsley Pascal; Abdur-Rahman, Lukman Olajide; Adekanye, Adedeji Olugbenga; Solagberu, Babatunde Akeeb

    2014-01-01

    Introduction Road traffic injury (RTI) has assumed major public health importance world-wide and the burden is heavier on the health-care infrastructure of countries in Sub-Saharan Africa. In Nigeria, RTI is the leading cause of trauma related morbidity and mortality. While there are some published epidemiological reports on RTI in the region, studies on the mechanism of causation of road traffic crashes (RTC) are not available. Methods Over a 9-month period, we prospectively captured the 571 victims of RTC presenting to a single tertiary health care center in Nigeria. Data collected include demographic data, Mechanism of causation of RTC, Injuries sustained and outcomes. Results Over three-quarters of the victims are young people and half were either traders (27.5%) or students (20%). Pedestrians, motorcycle riders and open truck occupants (people sitting at the rear loading compartment of trucks) often had fatal injuries. Analysis of collision patterns showed that lone crashes were the most frequent though car-to-motorcycle crashes caused a quarter of the deaths. Host factors (over-speeding driver, driver misjudgment, sleeping driver etc.) were responsible for four-fifths of the crashes while vehicular and environmental factors accounted for the remaining. On binary regression analysis, head injured victims had higher odds of dying than the non-head injured (Odds ratio = 6.5). Conclusion This paper elucidates the mechanisms of causation of and types of injuries sustained following RTC in Nigeria and thus provide opportunities for prevention and control of this unacceptable situation. PMID:25780490

  20. Improvement of low bioavailability of a novel factor Xa inhibitor through formulation of cationic additives in its oral dosage form.

    PubMed

    Fujii, Yoshimine; Kanamaru, Taro; Kikuchi, Hiroshi; Nakagami, Hiroaki; Yamashita, Shinji; Akashi, Mitsuru; Sakuma, Shinji

    2011-12-15

    A clinical trial of (2S)-2-[4-[[(3S)-1-acetimidoyl-3-pyrrolidinyl]oxy]phenyl]-3-(7-amidino-2-naphtyl) propanoic acid (DX-9065) revealed that its oral bioavailability was only 3% when it was administered as a conventional capsule formulation. The low bioavailability of DX-9065 was likely caused by both its poor membrane permeability and its electrostatic interaction with anionic bile acids. We hypothesized that DX-9065 absorption would be enhanced when the cationic drug was free from the complex through its replacement with other cationic substances. Polystyrene nanospheres coated with cationic poly(vinylamine) and cholestyramine, which is clinically used as a cholesterol-lowering agent, dramatically prevented DX-9065 from interacting with chenodeoxycholic acid in vitro. Successive animal experiments showed that bioavailability of DX-9065 administered with these cationic substances was 2-3 times that of DX-9065 administered solely. A dry syrup formulation with one-half of a minimal cholesterol-lowering equivalent dose of cholestyramine was designed, and the clinical trial was resumed. A 1.3-fold increase in bioavailability of DX-9065 was observed when the dry syrup was administered. We successfully demonstrated that DX-9065 absorption was enhanced when the drug was administered with cationic additives; however, it appeared that the absorption-enhancing function of cholestyramine largely depended on its dose. The dose escalation is probably prerequisite for the significant improvement of DX-9065 absorption in humans. PMID:22001539

  1. Host defenses trigger salmonella's arsenal.

    PubMed

    Keestra, A Marijke; Bäumler, Andreas J

    2011-03-17

    Salmonella survives in macrophages by using a molecular syringe to deliver proteins into the host-cell cytosol where they manipulate phagocyte physiology. Arpaia and colleagues (Arpaia et al., 2011) show that deployment of this virulence factor is triggered by the very responses that are intended to confer host resistance. PMID:21402352

  2. Baseline Prediction of Combination Therapy Outcome in Hepatitis C Virus 1b Infected Patients by Discriminant Analysis Using Viral and Host Factors

    PubMed Central

    Saludes, Verónica; Bracho, Maria Alma; Valero, Oliver; Ardèvol, Mercè; Planas, Ramón; González-Candelas, Fernando; Ausina, Vicente; Martró, Elisa

    2010-01-01

    Background Current treatment of chronic hepatitis C virus (HCV) infection has limited efficacy −especially among genotype 1 infected patients−, is costly, and involves severe side effects. Thus, predicting non-response is of major interest for both patient wellbeing and health care expense. At present, treatment cannot be individualized on the basis of any baseline predictor of response. We aimed to identify pre-treatment clinical and virological parameters associated with treatment failure, as well as to assess whether therapy outcome could be predicted at baseline. Methodology Forty-three HCV subtype 1b (HCV-1b) chronically infected patients treated with pegylated-interferon alpha plus ribavirin were retrospectively studied (21 responders and 22 non-responders). Host (gender, age, weight, transaminase levels, fibrosis stage, and source of infection) and viral-related factors (viral load, and genetic variability in the E1–E2 and Core regions) were assessed. Logistic regression and discriminant analyses were used to develop predictive models. A “leave-one-out” cross-validation method was used to assess the reliability of the discriminant models. Principal Findings Lower alanine transaminase levels (ALT, p = 0.009), a higher number of quasispecies variants in the E1–E2 region (number of haplotypes, nHap_E1–E2) (p = 0.003), and the absence of both amino acid arginine at position 70 and leucine at position 91 in the Core region (p = 0.039) were significantly associated with treatment failure. Therapy outcome was most accurately predicted by discriminant analysis (90.5% sensitivity and 95.5% specificity, 85.7% sensitivity and 81.8% specificity after cross-validation); the most significant variables included in the predictive model were the Core amino acid pattern, the nHap_E1–E2, and gamma-glutamyl transferase and ALT levels. Conclusions and Significance Discriminant analysis has been shown as a useful tool to predict treatment outcome using

  3. Corticotropin-releasing factor receptors CRF1 and CRF2 exert both additive and opposing influences on defensive startle behavior.

    PubMed

    Risbrough, Victoria B; Hauger, Richard L; Roberts, Amanda L; Vale, Wylie W; Geyer, Mark A

    2004-07-21

    The corticotropin-releasing factor (CRF) receptors (CRF1 and CRF2) are crucial mediators of physiological and behavioral responses to stress. In animals, CRF1 appears to primarily mediate CRF-induced anxiety-like responses, but the role of CRF2 during stress is still unclear. Here we report the effects of CRF1 and CRF2 on the magnitude and plasticity of defensive startle responses in mice. Startle plasticity is measured by inhibition of startle by sensory stimuli, i.e., prepulse inhibition (PPI), and is disrupted in patients with panic or posttraumatic stress disorders in which CRF neurotransmission may be overactive. Pharmacological blockade of CRF1 reversed both CRF-induced increases in startle and CRF-induced deficits in PPI. CRF2 blockade attenuated high-dose but not low-dose CRF-induced increases in startle and reduced PPI. Conversely, activation of CRF2 enhanced PPI. CRF had no effect on startle and increased PPI in CRF1 knock-out mice. These data indicate that CRF receptors act in concert to increase the magnitude of defensive startle yet in opposition to regulate the flexibility of startle. These data support a new model of respective CRF receptor roles in stress-related behavior such that, although both receptors enhance the magnitude of defensive responses, CRF1 receptors contravene, whereas CRF2 receptors enhance, the impact of sensory information on defensive behavior. We hypothesize that excessive CRF1 activation combined with reduced CRF2 signaling may contribute to information processing deficits seen in panic and posttraumatic stress disorder patients and support CRF1-specific pharmacotherapy. PMID:15269266

  4. The severity of retinal pathology in homozygous Crb1rd8/rd8 mice is dependent on additional genetic factors

    PubMed Central

    Luhmann, Ulrich F.O.; Carvalho, Livia S.; Holthaus, Sophia-Martha kleine; Cowing, Jill A.; Greenaway, Simon; Chu, Colin J.; Herrmann, Philipp; Smith, Alexander J.; Munro, Peter M.G.; Potter, Paul; Bainbridge, James W.B.; Ali, Robin R.

    2015-01-01

    Understanding phenotype–genotype correlations in retinal degeneration is a major challenge. Mutations in CRB1 lead to a spectrum of autosomal recessive retinal dystrophies with variable phenotypes suggesting the influence of modifying factors. To establish the contribution of the genetic background to phenotypic variability associated with the Crb1rd8/rd8 mutation, we compared the retinal pathology of Crb1rd8/rd8/J inbred mice with that of two Crb1rd8/rd8 lines backcrossed with C57BL/6JOlaHsd mice. Topical endoscopic fundal imaging and scanning laser ophthalmoscopy fundus images of all three Crb1rd8/rd8 lines showed a significant increase in the number of inferior retinal lesions that was strikingly variable between the lines. Optical coherence tomography, semithin, ultrastructural morphology and assessment of inflammatory and vascular marker by immunohistochemistry and quantitative reverse transcriptase-polymerase chain reaction revealed that the lesions were associated with photoreceptor death, Müller and microglia activation and telangiectasia-like vascular remodelling—features that were stable in the inbred, variable in the second, but virtually absent in the third Crb1rd8/rd8 line, even at 12 months of age. This suggests that the Crb1rd8/rd8 mutation is necessary, but not sufficient for the development of these degenerative features. By whole-genome SNP analysis of the genotype–phenotype correlation, a candidate region on chromosome 15 was identified. This may carry one or more genetic modifiers for the manifestation of the retinal pathology associated with mutations in Crb1. This study also provides insight into the nature of the retinal vascular lesions that likely represent a clinical correlate for the formation of retinal telangiectasia or Coats-like vasculopathy in patients with CRB1 mutations that are thought to depend on such genetic modifiers. PMID:25147295

  5. The severity of retinal pathology in homozygous Crb1rd8/rd8 mice is dependent on additional genetic factors.

    PubMed

    Luhmann, Ulrich F O; Carvalho, Livia S; Holthaus, Sophia-Martha Kleine; Cowing, Jill A; Greenaway, Simon; Chu, Colin J; Herrmann, Philipp; Smith, Alexander J; Munro, Peter M G; Potter, Paul; Bainbridge, James W B; Ali, Robin R

    2015-01-01

    Understanding phenotype-genotype correlations in retinal degeneration is a major challenge. Mutations in CRB1 lead to a spectrum of autosomal recessive retinal dystrophies with variable phenotypes suggesting the influence of modifying factors. To establish the contribution of the genetic background to phenotypic variability associated with the Crb1(rd8/rd8) mutation, we compared the retinal pathology of Crb1(rd8/rd8)/J inbred mice with that of two Crb1(rd8/rd8) lines backcrossed with C57BL/6JOlaHsd mice. Topical endoscopic fundal imaging and scanning laser ophthalmoscopy fundus images of all three Crb1(rd8/rd8) lines showed a significant increase in the number of inferior retinal lesions that was strikingly variable between the lines. Optical coherence tomography, semithin, ultrastructural morphology and assessment of inflammatory and vascular marker by immunohistochemistry and quantitative reverse transcriptase-polymerase chain reaction revealed that the lesions were associated with photoreceptor death, Müller and microglia activation and telangiectasia-like vascular remodelling-features that were stable in the inbred, variable in the second, but virtually absent in the third Crb1(rd8/rd8) line, even at 12 months of age. This suggests that the Crb1(rd8/rd8) mutation is necessary, but not sufficient for the development of these degenerative features. By whole-genome SNP analysis of the genotype-phenotype correlation, a candidate region on chromosome 15 was identified. This may carry one or more genetic modifiers for the manifestation of the retinal pathology associated with mutations in Crb1. This study also provides insight into the nature of the retinal vascular lesions that likely represent a clinical correlate for the formation of retinal telangiectasia or Coats-like vasculopathy in patients with CRB1 mutations that are thought to depend on such genetic modifiers. PMID:25147295

  6. Physiological basis of tolerance to complete submergence in rice involves genetic factors in addition to the SUB1 gene.

    PubMed

    Singh, Sudhanshu; Mackill, David J; Ismail, Abdelbagi M

    2014-01-01

    1 lines. This suggests the possibility of further improvements in submergence tolerance by incorporating additional traits present in FR13A or other similar landraces. PMID:25281725

  7. Physiological basis of tolerance to complete submergence in rice involves genetic factors in addition to the SUB1 gene

    PubMed Central

    Singh, Sudhanshu; Mackill, David J.; Ismail, Abdelbagi M.

    2014-01-01

    1 lines. This suggests the possibility of further improvements in submergence tolerance by incorporating additional traits present in FR13A or other similar landraces. PMID:25281725

  8. Temporal Assessment of the Impact of Exposure to Cow Feces in Two Watersheds by Multiple Host-Specific PCR Assays

    EPA Science Inventory

    Exposure to feces in two watersheds with different management histories was assessed by tracking cattle feces bacterial populations using multiple host-specific PCR assays. In addition, environmental factors affecting the occurrence of these markers were identified. Each assay wa...

  9. Mutations in Encephalomyocarditis Virus 3A Protein Uncouple the Dependency of Genome Replication on Host Factors Phosphatidylinositol 4-Kinase IIIα and Oxysterol-Binding Protein

    PubMed Central

    Dorobantu, Cristina M.; Albulescu, Lucian; Lyoo, Heyrhyoung; van Kampen, Mirjam; De Francesco, Raffaele; Lohmann, Volker; Harak, Christian; van der Schaar, Hilde M.; Strating, Jeroen R. P. M.; Gorbalenya, Alexander E.

    2016-01-01

    ABSTRACT Positive-strand RNA [(+)RNA] viruses are true masters of reprogramming host lipid trafficking and synthesis to support virus genome replication. Via their membrane-associated 3A protein, picornaviruses of the genus Enterovirus (e.g., poliovirus, coxsackievirus, and rhinovirus) subvert Golgi complex-localized phosphatidylinositol 4-kinase IIIβ (PI4KB) to generate “replication organelles” (ROs) enriched in phosphatidylinositol 4-phosphate (PI4P). PI4P lipids serve to accumulate oxysterol-binding protein (OSBP), which subsequently transfers cholesterol to the ROs in a PI4P-dependent manner. Single-point mutations in 3A render enteroviruses resistant to both PI4KB and OSBP inhibition, indicating coupled dependency on these host factors. Recently, we showed that encephalomyocarditis virus (EMCV), a picornavirus that belongs to the Cardiovirus genus, also builds PI4P/cholesterol-enriched ROs. Like the hepatitis C virus (HCV) of the Flaviviridae family, it does so by hijacking the endoplasmic reticulum (ER)-localized phosphatidylinositol 4-kinase IIIα (PI4KA). Here we provide genetic evidence for the critical involvement of EMCV protein 3A in this process. Using a genetic screening approach, we selected EMCV mutants with single amino acid substitutions in 3A, which rescued RNA virus replication upon small interfering RNA (siRNA) knockdown or pharmacological inhibition of PI4KA. In the presence of PI4KA inhibitors, the mutants no longer induced PI4P, OSBP, or cholesterol accumulation at ROs, which aggregated into large cytoplasmic clusters. In contrast to the enterovirus escape mutants, we observed little if any cross-resistance of EMCV mutants to OSBP inhibitors, indicating an uncoupled level of dependency of their RNA replication on PI4KA and OSBP activities. This report may contribute to a better understanding of the roles of PI4KA and OSBP in membrane modifications induced by (+)RNA viruses. IMPORTANCE Positive-strand RNA viruses modulate lipid

  10. Mutations in Encephalomyocarditis Virus 3A Protein Uncouple the Dependency of Genome Replication on Host Factors Phosphatidylinositol 4-Kinase IIIα and Oxysterol-Binding Protein.

    PubMed

    Dorobantu, Cristina M; Albulescu, Lucian; Lyoo, Heyrhyoung; van Kampen, Mirjam; De Francesco, Raffaele; Lohmann, Volker; Harak, Christian; van der Schaar, Hilde M; Strating, Jeroen R P M; Gorbalenya, Alexander E; van Kuppeveld, Frank J M

    2016-01-01

    Positive-strand RNA [(+)RNA] viruses are true masters of reprogramming host lipid trafficking and synthesis to support virus genome replication. Via their membrane-associated 3A protein, picornaviruses of the genus Enterovirus (e.g., poliovirus, coxsackievirus, and rhinovirus) subvert Golgi complex-localized phosphatidylinositol 4-kinase IIIβ (PI4KB) to generate "replication organelles" (ROs) enriched in phosphatidylinositol 4-phosphate (PI4P). PI4P lipids serve to accumulate oxysterol-binding protein (OSBP), which subsequently transfers cholesterol to the ROs in a PI4P-dependent manner. Single-point mutations in 3A render enteroviruses resistant to both PI4KB and OSBP inhibition, indicating coupled dependency on these host factors. Recently, we showed that encephalomyocarditis virus (EMCV), a picornavirus that belongs to the Cardiovirus genus, also builds PI4P/cholesterol-enriched ROs. Like the hepatitis C virus (HCV) of the Flaviviridae family, it does so by hijacking the endoplasmic reticulum (ER)-localized phosphatidylinositol 4-kinase IIIα (PI4KA). Here we provide genetic evidence for the critical involvement of EMCV protein 3A in this process. Using a genetic screening approach, we selected EMCV mutants with single amino acid substitutions in 3A, which rescued RNA virus replication upon small interfering RNA (siRNA) knockdown or pharmacological inhibition of PI4KA. In the presence of PI4KA inhibitors, the mutants no longer induced PI4P, OSBP, or cholesterol accumulation at ROs, which aggregated into large cytoplasmic clusters. In contrast to the enterovirus escape mutants, we observed little if any cross-resistance of EMCV mutants to OSBP inhibitors, indicating an uncoupled level of dependency of their RNA replication on PI4KA and OSBP activities. This report may contribute to a better understanding of the roles of PI4KA and OSBP in membrane modifications induced by (+)RNA viruses. IMPORTANCE Positive-strand RNA viruses modulate lipid homeostasis to

  11. Host preferences in host-seeking and blood-fed mosquitoes in Switzerland.

    PubMed

    Schönenberger, A C; Wagner, S; Tuten, H C; Schaffner, F; Torgerson, P; Furrer, S; Mathis, A; Silaghi, C

    2016-03-01

    The avian zoonotic agent for West Nile virus (WNV) can cause neuroinvasive disease in horses and humans and is expanding its range in Europe. Analyses of the risk for transmission to these hosts in non-endemic areas are necessary. Host preferences of mosquitoes (Diptera: Culicidae), the main vectors of WNV, were determined in Switzerland using animal-baited trap (horse, chickens) experiments at a natural and a periurban site. This was undertaken on four occasions during May-September 2014. In addition, the hosts of 505 blood-fed mosquitoes collected in a zoo and in the field were determined. Mosquito data obtained in the animal bait experiments were corrected for host weight and body surface area and by Kleiber's scaling factor. Collections of 11-14 different mosquito species were achieved with these approaches. Statistically significant host preferences were identified in three species in both approaches. The other species showed opportunistic feeding behaviours to varying extents. Specifically, the invasive species Hulecoeteomyia japonica (= Aedes japonicus) was identified for the first time as feeding on avians in nature. Abundance data, spatiotemporal activity and laboratory vector competence for WNV suggested that, in addition to the main WNV vector Culex pipiens, H. japonica and Aedimorphus vexans (= Aedes vexans) are the most likely candidate bridge vectors for WNV transmission in Switzerland. PMID:26685926

  12. Host Responses to Biofilm.

    PubMed

    Watters, C; Fleming, D; Bishop, D; Rumbaugh, K P

    2016-01-01

    From birth to death the human host immune system interacts with bacterial cells. Biofilms are communities of microbes embedded in matrices composed of extracellular polymeric substance (EPS), and have been implicated in both the healthy microbiome and disease states. The immune system recognizes many different bacterial patterns, molecules, and antigens, but these components can be camouflaged in the biofilm mode of growth. Instead, immune cells come into contact with components of the EPS matrix, a diverse, hydrated mixture of extracellular DNA (bacterial and host), proteins, polysaccharides, and lipids. As bacterial cells transition from planktonic to biofilm-associated they produce small molecules, which can increase inflammation, induce cell death, and even cause necrosis. To survive, invading bacteria must overcome the epithelial barrier, host microbiome, complement, and a variety of leukocytes. If bacteria can evade these initial cell populations they have an increased chance at surviving and causing ongoing disease in the host. Planktonic cells are readily cleared, but biofilms reduce the effectiveness of both polymorphonuclear neutrophils and macrophages. In addition, in the presence of these cells, biofilm formation is actively enhanced, and components of host immune cells are assimilated into the EPS matrix. While pathogenic biofilms contribute to states of chronic inflammation, probiotic Lactobacillus biofilms cause a negligible immune response and, in states of inflammation, exhibit robust antiinflammatory properties. These probiotic biofilms colonize and protect the gut and vagina, and have been implicated in improved healing of damaged skin. Overall, biofilms stimulate a unique immune response that we are only beginning to understand. PMID:27571696

  13. Integration Host Factor is required for FarR repression of the farAB-encoded efflux pump of Neisseria gonorrhoeae.

    PubMed

    Lee, Eun-Hee; Hill, Stuart A; Napier, Ruth; Shafer, William M

    2006-06-01

    The farAB operon encodes an efflux pump system that mediates the resistance of Neisseria gonorrhoeae to antimicrobial long-chain fatty acids. We previously observed that expression of farAB is negatively regulated by the FarR repressor. In this study, we examined the molecular mechanism by which FarR represses expression of farAB. DNase I footprinting analysis, coupled with a deletion analysis of the farAB promoter region, indicated that FarR binds to three sites (termed sites A, B and C) within the DNA sequence upstream of farA; genetic analysis revealed, however, that site B is not required for FarR repression of farAB. This repression also required the presence of Integration Host Factor (IHF), which was found to bind to sequences located between FarR binding sites A and C. We determined that IHF binding to the farAB promoter region could inhibit transcription in vitro and that such binding induced a bending of the target DNA, which we propose to be important in regulating this operon. IHF binding to the promoter region was found to stabilize the binding of FarR to its binding sites A and C and as a consequence, enhanced repression of farAB expression mediated by FarR. We propose a model in which expression of the farAB-encoded efflux pump in N. gonorrhoeae is modulated by the DNA binding activities of FarR and IHF. PMID:16796676

  14. Assessment of the Electronic Factors Determining the Thermodynamics of "Oxidative Addition" of C-H and N-H Bonds to Ir(I) Complexes.

    PubMed

    Wang, David Y; Choliy, Yuriy; Haibach, Michael C; Hartwig, John F; Krogh-Jespersen, Karsten; Goldman, Alan S

    2016-01-13

    A study of electronic factors governing the thermodynamics of C-H and N-H bond addition to Ir(I) complexes was conducted. DFT calculations were performed on an extensive series of trans-(PH3)2IrXL complexes (L = NH3 and CO; X = various monodentate ligands) to parametrize the relative σ- and π-donating/withdrawing properties of the various ligands, X. Computed energies of oxidative addition of methane to a series of three- and four-coordinate Ir(I) complexes bearing an ancillary ligand, X, were correlated with the resulting (σ(X), π(X)) parameter set. Regression analysis indicates that the thermodynamics of addition of methane to trans-(PH3)2IrX are generally strongly disfavored by increased σ-donation from the ligand X, in contradiction to widely held views on oxidative addition. The trend for oxidative addition of methane to four-coordinate Ir(I) was closely related to that observed for the three-coordinate complexes, albeit slightly more complicated. The computational analysis was found to be consistent with the rates of reductive elimination of benzene from a series of isoelectronic Ir(III) phenyl hydride complexes, measured experimentally in this work and previously reported. Extending the analysis of ancillary ligand energetic effects to the oxidative addition of ammonia to three-coordinate Ir(I) complexes leads to the conclusion that increasing σ-donation by X also disfavors oxidative addition of N-H bonds to trans-(PH3)2IrX. However, coordination of NH3 to the Ir(I) center is disfavored even more strongly by increasing σ-donation by X, which explains why the few documented examples of H-NH2 oxidative addition to transition metals involve complexes with strongly σ-donating ligands situated trans to the site of addition. An orbital-based rationale for the observed results is presented. PMID:26652221

  15. Mixed Lineage Leukemia 5 (MLL5) Protein Regulates Cell Cycle Progression and E2F1-responsive Gene Expression via Association with Host Cell Factor-1 (HCF-1)*

    PubMed Central

    Zhou, Peipei; Wang, Zhilong; Yuan, Xiujie; Zhou, Cuihong; Liu, Lulu; Wan, Xiaoling; Zhang, Feng; Ding, Xiaodan; Wang, Chuangui; Xiong, Sidong; Wang, Zhen; Yuan, Jinduo; Li, Qiang; Zhang, Yan

    2013-01-01

    Trithorax group proteins methylate lysine 4 of histone 3 (H3K4) at active gene promoters. MLL5 protein, a member of the Trithorax protein family, has been implicated in the control of the cell cycle progression; however, the underlying molecular mechanism(s) have not been fully determined. In this study, we found that the MLL5 protein can associate with the cell cycle regulator “host cell factor” (HCF-1). The interaction between MLL5 and HCF-1 is mediated by the “HCF-1 binding motif” (HBM) of the MLL5 protein and the Kelch domain of the HCF-1 protein. Confocal microscopy showed that the MLL5 protein largely colocalized with HCF-1 in the nucleus. Knockdown of MLL5 resulted in reduced cell proliferation and cell cycle arrest in the G1 phase. Moreover, down-regulation of E2F1 target gene expression and decreased H3K4me3 levels at E2F1-responsive promoters were observed in MLL5 knockdown cells. Additionally, the core subunits, including ASH2L, RBBP5, and WDR5, that are necessary for effective H3K4 methyltransferase activities of the Trithorax protein complexes, were absent in the MLL5 complex, suggesting that a distinct mechanism may be used by MLL5 for exerting its H3K4 methyltransferase activity. Together, our findings demonstrate that MLL5 could associate with HCF-1 and then be recruited to E2F1-responsive promoters to stimulate H3K4 trimethylation and transcriptional activation, thereby facilitating the cell cycle G1 to S phase transition. PMID:23629655

  16. Integration Host Factor Is Required for RpoN-Dependent hrpL Gene Expression and Controls Motility by Positively Regulating rsmB sRNA in Erwinia amylovora.

    PubMed

    Lee, Jae Hoon; Zhao, Youfu

    2016-01-01

    Erwinia amylovora requires an hrp-type III secretion system (T3SS) to cause disease. It has been reported that HrpL, the master regulator of T3SS, is transcriptionally regulated by sigma factor 54 (RpoN), YhbH, and HrpS. In this study, the role of integration host factor (IHF) in regulating hrpL and T3SS gene expression was investigated. IHF is a nucleoid-associated protein that regulates gene expression by influencing nucleoid structure and DNA bending. Our results showed that both ihfA and ihfB mutants of E. amylovora did not induce necrotic lesions on pear fruits. Growth of both mutants was greatly reduced, and expression of the hrpL and T3SS genes was significantly down-regulated as compared with those of the wild type. In addition, expression of the ihfA, but not the ihfB gene, was under auto-suppression by IHF. Furthermore, both ihfA and ihfB mutants were hypermotile, due to significantly reduced expression of small RNA (sRNA) rsmB. Electrophoresis mobility shift assay further confirmed that IHF binds to the promoters of the hrpL and ihfA genes, as well as the rsmB sRNA gene. These results indicate that IHF is required for RpoN-dependent hrpL gene expression and virulence, and controls motility by positively regulating the rsmB sRNA in E. amylovora. PMID:26368515

  17. Proteome-Wide Overexpression of Host Proteins for Identification of Factors Affecting Tombusvirus RNA Replication: an Inhibitory Role of Protein Kinase C

    PubMed Central

    Shah Nawaz-ul-Rehman, Muhammad; Martinez-Ochoa, Natalia; Pascal, Helene; Sasvari, Zsuzsanna; Herbst, Christin; Xu, Kai; Baker, Jannine; Sharma, Monika; Herbst, Alan

    2012-01-01

    To identify host genes affecting replication of Tomato bushy stunt virus (TBSV), a small model positive-stranded RNA virus, we overexpressed 5,500 yeast proteins individually in Saccharomyces cerevisiae, which supports TBSV replication. In total, we identified 141 host proteins, and overexpression of 40 of those increased and the remainder decreased the accumulation of a TBSV replicon RNA. Interestingly, 36 yeast proteins were identified previously by various screens, greatly strengthening the relevance of these host proteins in TBSV replication. To validate the results from the screen, we studied the effect of protein kinase C1 (Pkc1), a conserved host kinase involved in many cellular processes, which inhibited TBSV replication when overexpressed. Using a temperature-sensitive mutant of Pkc1p revealed a high level of TBSV replication at a semipermissive temperature, further supporting the idea that Pkc1p is an inhibitor of TBSV RNA replication. A direct inhibitory effect of Pkc1p was shown in a cell-free yeast extract-based TBSV replication assay, in which Pkc1p likely phosphorylates viral replication proteins, decreasing their abilities to bind to the viral RNA. We also show that cercosporamide, a specific inhibitor of Pkc-like kinases, leads to increased TBSV replication in yeast, in plant single cells, and in whole plants, suggesting that Pkc-related pathways are potent inhibitors of TBSV in several hosts. PMID:22718827

  18. Novel Host-Related Virulence Factors Are Encoded by Squirrelpox Virus, the Main Causative Agent of Epidemic Disease in Red Squirrels in the UK

    PubMed Central

    Kjær, Karina Hansen; Wood, Ann R.; Hughes, Margaret; Martensen, Pia Møller; Radford, Alan D.; Hall, Neil; Chantrey, Julian

    2014-01-01

    Squirrelpox virus (SQPV) shows little evidence for morbidity or mortality in North American grey squirrels (Sciurus carolinensis), in which the virus is endemic. However, more recently the virus has emerged to cause epidemics with high mortality in Eurasian red squirrels (S. vulgaris) in Great Britain, which are now threatened. Here we report the genome sequence of SQPV. Comparison with other Poxviridae revealed a core set of poxvirus genes, the phylogeny of which showed SQPV to be in a new Chordopoxvirus subfamily between the Molluscipoxviruses and Parapoxviruses. A number of SQPV genes were related to virulence, including three major histocomaptibility class I homologs, and one CD47 homolog. In addition, a novel potential virulence factor showing homology to mammalian oligoadenylate synthetase (OAS) was identified. This family of proteins normally causes activation of an endoribonuclease (RNaseL) within infected cells. The putative function of this novel SQPV protein was predicted in silico. PMID:24983354

  19. Phloem restriction of viroids in three citrus hosts is overcome by grafting with Etrog citron: potential involvement of a translocatable factor.

    PubMed

    Bani-Hashemian, Seyed Mehdi; Pensabene-Bellavia, Giovanni; Duran-Vila, Nuria; Serra, Pedro

    2015-08-01

    Viroid systemic spread involves cell-to-cell movement from initially infected cells via plasmodesmata, long-distance movement within the phloem and again cell-to-cell movement to invade distal tissues including the mesophyll. Citrus exocortis viroid (CEVd), hop stunt viroid, citrus bent leaf viroid, citrus dwarfing viroid, citrus bark cracking viroid and citrus viroid V remained phloem restricted when singly infecting Citrus karna, Citrus aurantium and Poncirus trifoliata, but not Etrog citron, where they were additionally detected in mesophyll protoplasts. However, when CEVd-infected C. karna was side-grafted with Etrog citron--with the resulting plants being composed of a C. karna stock and an Etrog citron branch--the viroid was detected in mesophyll protoplasts of the former, thus indicating that the ability of Etrog citron to support viroid invasion of non-vascular tissues was transferred to the stock. Further results suggest that a translocatable factor from Etrog citron mediates this viroid trafficking. PMID:25888624

  20. Anuran Host Species Influences Site Fidelity of Halipegus occidualis.

    PubMed

    Stigge, Heather A; Bolek, Matthew G

    2016-02-01

    Helminths often demonstrate preferential site selection in which a parasite will only occur in 1 microhabitat or a restricted portion of its fundamental niche within its host. However, factors responsible for helminth site specificity are poorly understood, and very little is known about how these factors vary among multiple host species. Some helminths, such as Halipegus occidualis, have been reported from different habitats (stomach or under the tongue) within multiple anuran host species, suggesting that the site selected varies within anuran species. This study examined the site selection by H. occidualis in 7 definitive anuran host species using experimental infections. Then, the site fidelity of H. occidualis was further tested by transplanting worms from under the tongue to the stomach and vice versa in different anuran host combinations, and the movement of worms was recorded. Halipegus occidualis individuals occupied the habitat under the tongue in 6 of 7 anuran species. However, worms always occupied the stomach of American bullfrogs (Lithobates catesbeianus) and were never found under the tongue or in the mouth of these hosts. More importantly, all worms remained in the original habitat when transplanted from the stomach to the stomach or the buccal cavity to the buccal cavity within another individual of the same amphibian species. However, when worms were transplanted from the stomach to the buccal cavity or vice versa in the same host species, the worms always migrated back to the original habitat. The main contribution of this study is that it experimentally documented the variability in the site fidelity of H. occidualis within multiple definitive host species and determined that site fidelity is not as strongly conserved in this genus as suggested previously. Additionally, this work suggests that the variation in site selection in different host species could lead to speciation of the parasites. PMID:26412569

  1. Survival to Parasitoids in an Insect Hosting Defensive Symbionts: A Multivariate Approach to Polymorphic Traits Affecting Host Use by Its Natural Enemy

    PubMed Central

    Bilodeau, Emilie; Guay, Jean-Frédéric; Turgeon, Julie; Cloutier, Conrad

    2013-01-01

    Insect parasitoids and their insect hosts represent a wide range of parasitic trophic relations that can be used to understand the evolution of biotic diversity on earth. Testing theories of coevolution between hosts and parasites is based on factors directly involved in host susceptibility and parasitoid virulence. We used controlled encounters with potential hosts of the Aphidius ervi wasp to elucidate behavioral and other phenotypic traits of host Acyrthosiphon pisum that most contribute to success or failure of parasitism. The host aphid is at an advanced stage of specialization on different crop plants, and exhibits intra-population polymorphism for traits of parasitoid avoidance and resistance based on clonal variation of color morph and anti-parasitoid bacterial symbionts. Randomly selected aphid clones from alfalfa and clover were matched in 5 minute encounters with wasps of two parasitoid lineages deriving from hosts of each plant biotype in a replicated transplant experimental design. In addition to crop plant affiliation (alfalfa, clover), aphid clones were characterized for color morph (green, pink), Hamiltonella defensa and Regiella insecticola symbionts, and frequently used behaviors in encounters with A. ervi wasps. A total of 12 explanatory variables were examined using redundancy analysis (RDA) to predict host survival or failure to A. ervi parasitism. Aphid color was the best univariate predictor, but was poorly predictive in the RDA model. In contrast, aphid host plant and symbionts were not significant univariate predictors, but significant predictors in the multivariate model. Aphid susceptibility to wasp acceptance as reflected in host attacks and oviposition clearly differed from its suitability to parasitism and progeny development. Parasitoid progeny were three times more likely to survive on clover than alfalfa host aphids, which was compensated by behaviorally adjusting eggs invested per host. Strong variation of the predictive power of

  2. Host Genetic Factors and Dendritic Cell Responses Associated with the Outcome of Interferon/Ribavirin Treatment in HIV-1/HCV Co-Infected Individuals

    PubMed Central

    Sehgal, Mohit; Zeremski, Marija; Talal, Andrew H.; Khan, Zafar K.; Capocasale, Renold; Philip, Ramila; Jain, Pooja

    2015-01-01

    HIV-1/HCV co-infection is a significant health problem. Highly active antiretroviral treatment (HAART) against HIV-1 has proved to be fairly successful. On the other hand, direct acting antiviral drugs against HCV have improved cure rates but high cost and development of drug resistance are important concerns. Therefore PEGylated interferon (PEG-IFN) and ribavirin (RBV) still remain essential components of HCV treatment, and identification of host factors that predict IFN/RBV treatment response is necessary for effective clinical management of HCV infection. Impaired dendritic cell (DC) and T cell responses are associated with HCV persistence. It has been shown that IFN/RBV treatment enhances HCV-specific T cell functions and it is likely that functional restoration of DCs is the underlying cause. To test this hypothesis, we utilized an antibody cocktail (consisting of DC maturation, adhesion and other surface markers) to perform comprehensive phenotypic characterization of myeloid DCs (mDCs) and plasmacytoid DCs (pDCs) in a cohort of HIV-1/HCV co-infected individuals undergoing IFN/RBV treatment. Our results show that pre-treatment frequencies of mDCs are lower in non-responders (NRs) compared to responders (SVRs) and healthy controls. Although, the treatment was able to restore the frequency of mDCs in NRs, it downregulated the frequency of CCR7+, CD54+ and CD62L+ mDCs. Pre-treatment frequencies of pDCs were lower in NRs and decreased further upon treatment. Compared to SVRs, NRs exhibited higher ratio of PD-L1+/CD86+ pDCs prior to treatment; and this ratio remained high even after treatment. These findings demonstrate that enumeration and phenotypic assessment of DCs before/during therapy can help predict the treatment outcome. We also show that before treatment, PBMCs from SVRs secrete higher amounts of IFN-γ compared to controls and NRs. Upon genotyping IFNL3 polymorphisms rs12979860, rs4803217 and ss469415590, we found rs12979860 to be a better predictor of

  3. Understanding host switching through ecological fitting

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Despite the fact that parasites are highly specialized to their hosts, extensive empirical evidence demonstrates that host switching rather than co-speciation is the most important factor influencing the origin of host-parasite associations. Ecological fitting in sloppy fitness space has been propos...

  4. Multiple host shifts by the emerging honeybee parasite, Varroa jacobsoni.

    PubMed

    Roberts, J M K; Anderson, D L; Tay, W T

    2015-05-01

    Host shifts are a key mechanism of parasite evolution and responsible for the emergence of many economically important pathogens. Varroa destructor has been a major factor in global honeybee (Apis mellifera) declines since shifting hosts from the Asian honeybee (Apis cerana) > 50 years ago. Until recently, only two haplotypes of V. destructor (Korea and Japan) had successfully host shifted to A. mellifera. In 2008, the sister species V. jacobsoni was found for the first time parasitizing A. mellifera in Papua New Guinea (PNG). This recent host shift presents a serious threat to world apiculture but also provides the opportunity to examine host shifting in this system. We used 12 microsatellites to compare genetic variation of V. jacobsoni on A. mellifera in PNG with mites on A. cerana in both PNG and surrounding regions. We identified two distinct lineages of V. jacobsoni reproducing on A. mellifera in PNG. Our analysis indicated independent host shift events have occurred through small numbers of mites shifting from local A. cerana populations. Additional lineages were found in the neighbouring Papua and Solomon Islands that had partially host shifted to A. mellifera, that is producing immature offspring on drone brood only. These mites were likely in transition to full colonization of A. mellifera. Significant population structure between mites on the different hosts suggested host shifted V. jacobsoni populations may not still reproduce on A. cerana, although limited gene flow may exist. Our studies provide further insight into parasite host shift evolution and help characterize this new Varroa mite threat to A. mellifera worldwide. PMID:25846956

  5. Mlc is a transcriptional activator with a key role in integrating cyclic AMP receptor protein and integration host factor regulation of leukotoxin RNA synthesis in Aggregatibacter actinomycetemcomitans

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aggregatibacter actinomycetemcomitans, a periodontal pathogen, synthesizes leukotoxin (LtxA), a protein that helps the bacterium evade the host immune response. Transcription of the ltxA operon is induced during anaerobic growth. The cAMP receptor protein (CRP) indirectly increases ltxA expression...

  6. New Host Factors Important for Respiratory Syncytial Virus (RSV) Replication Revealed by a Novel Microfluidics Screen for Interactors of Matrix (M) Protein*

    PubMed Central

    Kipper, Sarit; Hamad, Samar; Caly, Leon; Avrahami, Dorit; Bacharach, Eran; Jans, David A.; Gerber, Doron; Bajorek, Monika

    2015-01-01

    Although human respiratory syncytial virus (RSV) is the most common cause of bronchiolitis and pneumonia in infants and elderly worldwide, there is no licensed RSV vaccine or effective drug treatment available. The RSV Matrix protein plays key roles in virus life cycle, being found in the nucleus early in infection in a transcriptional inhibitory role, and later localizing in viral inclusion bodies before coordinating viral assembly and budding at the plasma membrane. In this study, we used a novel, high throughput microfluidics platform and custom human open reading frame library to identify novel host cell binding partners of RSV matrix. Novel interactors identified included proteins involved in host transcription regulation, the innate immunity response, cytoskeletal regulation, membrane remodeling, and cellular trafficking. A number of these interactions were confirmed by immunoprecipitation and cellular colocalization approaches. Importantly, the physiological significance of matrix interaction with the actin-binding protein cofilin 1, caveolae protein Caveolin 2, and the zinc finger protein ZNF502 was confirmed. siRNA knockdown of the host protein levels resulted in reduced RSV virus production in infected cells. These results have important implications for future antiviral strategies aimed at targets of RSV matrix in the host cell. PMID:25556234

  7. A ToxA-like protein from Cochliobolus heterostrophus induces light-dependent leaf necrosis and acts as a virulence factor with host selectivity on maize

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ToxA, the first discovered fungal proteinaceous host-selective toxin (HST), was originally identified in 1989 from the tan spot fungus Pyrenophora tritici-repentis (Ptr). About 25 years later, a homolog was identified in the leaf/glume blotch fungus Stagonospora nodorum (Parastagonospora nodorum), ...

  8. Elongation Factor-1a is a novel protein associated with host cell invasion and a potential protective antigen of Cryptosporidium parvum*

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The phylum Apicomplexa comprises obligate intracellular parasites that infect vertebrates. All invasive forms of Apicomplexa possess a unique complex of organelles at the anterior end, referred to as the apical complex, which is involved in host cell invasion. Previously, we generated the chicken m...

  9. Phenylethynyl Containing Reactive Additives

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Smith, Joseph G., Jr. (Inventor); Hergenrother, Paul M. (Inventor)

    2002-01-01

    Phenylethynyl containing reactive additives were prepared from aromatic diamine, containing phenylethvnvl groups and various ratios of phthalic anhydride and 4-phenylethynviphthalic anhydride in glacial acetic acid to form the imide in one step or in N-methyl-2-pvrrolidinone to form the amide acid intermediate. The reactive additives were mixed in various amounts (10% to 90%) with oligomers containing either terminal or pendent phenylethynyl groups (or both) to reduce the melt viscosity and thereby enhance processability. Upon thermal cure, the additives react and become chemically incorporated into the matrix and effect an increase in crosslink density relative to that of the host resin. This resultant increase in crosslink density has advantageous consequences on the cured resin properties such as higher glass transition temperature and higher modulus as compared to that of the host resin.

  10. Use of a Generalized Additive Model to Investigate Key Abiotic Factors Affecting Microcystin Cellular Quotas in Heavy Bloom Areas of Lake Taihu

    PubMed Central

    Tao, Min; Xie, Ping; Chen, Jun; Qin, Boqiang; Zhang, Dawen; Niu, Yuan; Zhang, Meng; Wang, Qing; Wu, Laiyan

    2012-01-01

    Lake Taihu is the third largest freshwater lake in China and is suffering from serious cyanobacterial blooms with the associated drinking water contamination by microcystin (MC) for millions of citizens. So far, most studies on MCs have been limited to two small bays, while systematic research on the whole lake is lacking. To explain the variations in MC concentrations during cyanobacterial bloom, a large-scale survey at 30 sites across the lake was conducted monthly in 2008. The health risks of MC exposure were high, especially in the northern area. Both Microcystis abundance and MC cellular quotas presented positive correlations with MC concentration in the bloom seasons, suggesting that the toxic risks during Microcystis proliferations were affected by variations in both Microcystis density and MC production per Microcystis cell. Use of a powerful predictive modeling tool named generalized additive model (GAM) helped visualize significant effects of abiotic factors related to carbon fixation and proliferation of Microcystis (conductivity, dissolved inorganic carbon (DIC), water temperature and pH) on MC cellular quotas from recruitment period of Microcystis to the bloom seasons, suggesting the possible use of these factors, in addition to Microcystis abundance, as warning signs to predict toxic events in the future. The interesting relationship between macrophytes and MC cellular quotas of Microcystis (i.e., high MC cellular quotas in the presence of macrophytes) needs further investigation. PMID:22384128

  11. Use of a generalized additive model to investigate key abiotic factors affecting microcystin cellular quotas in heavy bloom areas of Lake Taihu.

    PubMed

    Tao, Min; Xie, Ping; Chen, Jun; Qin, Boqiang; Zhang, Dawen; Niu, Yuan; Zhang, Meng; Wang, Qing; Wu, Laiyan

    2012-01-01

    Lake Taihu is the third largest freshwater lake in China and is suffering from serious cyanobacterial blooms with the associated drinking water contamination by microcystin (MC) for millions of citizens. So far, most studies on MCs have been limited to two small bays, while systematic research on the whole lake is lacking. To explain the variations in MC concentrations during cyanobacterial bloom, a large-scale survey at 30 sites across the lake was conducted monthly in 2008. The health risks of MC exposure were high, especially in the northern area. Both Microcystis abundance and MC cellular quotas presented positive correlations with MC concentration in the bloom seasons, suggesting that the toxic risks during Microcystis proliferations were affected by variations in both Microcystis density and MC production per Microcystis cell. Use of a powerful predictive modeling tool named generalized additive model (GAM) helped visualize significant effects of abiotic factors related to carbon fixation and proliferation of Microcystis (conductivity, dissolved inorganic carbon (DIC), water temperature and pH) on MC cellular quotas from recruitment period of Microcystis to the bloom seasons, suggesting the possible use of these factors, in addition to Microcystis abundance, as warning signs to predict toxic events in the future. The interesting relationship between macrophytes and MC cellular quotas of Microcystis (i.e., high MC cellular quotas in the presence of macrophytes) needs further investigation. PMID:22384128

  12. Outpatient management of postbiopsy pneumothorax with small-caliber chest tubes: factors affecting the need for prolonged drainage and additional interventions.

    PubMed

    Gupta, Sanjay; Hicks, Marshall E; Wallace, Michael J; Ahrar, Kamran; Madoff, David C; Murthy, Ravi

    2008-01-01

    The aim of this study was to evaluate the efficacy of outpatient management of postbiopsy pneumothoraces with small-caliber chest tubes and to assess the factors that influence the need for prolonged drainage or additional interventions. We evaluated the medical records of patients who were treated with small-caliber chest tubes attached to Heimlich valves for pneumothoraces resulting from image-guided transthoracic needle biopsy to determine the hospital admission rates, the number of days the catheters were left in place, and the need for further interventions. We also evaluated the patient, lesion, and biopsy technique characteristics to determine their influence on the need for prolonged catheter drainage or additional interventions. Of the 191 patients included in our study, 178 (93.2%) were treated as outpatients. Ten patients (5.2%) were admitted for chest tube-related problems, either for underwater suction (n = 8) or f