Science.gov

Sample records for additional host factors

  1. Host factors exploited by retroviruses.

    PubMed

    Goff, Stephen P

    2007-04-01

    Retroviruses make a long and complex journey from outside the cell to the nucleus in the early stages of infection, and then an equally long journey back out again in the late stages of infection. Ongoing efforts are identifying an enormous array of cellular proteins that are used by the viruses in the course of their travels. These host factors are potential new targets for therapeutic intervention.

  2. Host Factors in Enterovirus 71 Replication ▿

    PubMed Central

    Shih, Shin-Ru; Stollar, Victor; Li, Mei-Ling

    2011-01-01

    Enterovirus 71 (EV71) infections continue to remain an important public health problem around the world, especially in the Asia-Pacific region. There is a significant mortality rate following such infections, and there is neither any proven therapy nor a vaccine for EV71. This has spurred much fundamental research into the replication of the virus. In this review, we discuss recent work identifying host cell factors which regulate the synthesis of EV71 RNA and proteins. Three of these proteins, heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1), far-upstream element-binding protein 2 (FBP2), and FBP1 are nuclear proteins which in EV71-infected cells are relocalized to the cytoplasm, and they influence EV71 internal ribosome entry site (IRES) activity. hnRNP A1 stimulates IRES activity but can be replaced by hnRNP A2. FBP2 is a negative regulatory factor with respect to EV71 IRES activity, whereas FBP1 has the opposite effect. Two other proteins, hnRNP K and reticulon 3, are required for the efficient synthesis of viral RNA. The cleavage stimulation factor 64K subunit (CstF-64) is a host protein that is involved in the 3′ polyadenylation of cellular pre-mRNAs, and recent work suggests that in EV71-infected cells, it may be cleaved by the EV71 3C protease. Such a cleavage would impair the processing of pre-mRNA to mature mRNAs. Host cell proteins play an important role in the replication of EV71, but much work remains to be done in order to understand how they act. PMID:21715481

  3. Allergic sensitization: host-immune factors

    PubMed Central

    2014-01-01

    Allergic sensitization is the outcome of a complex interplay between the allergen and the host in a given environmental context. The first barrier encountered by an allergen on its way to sensitization is the mucosal epithelial layer. Allergic inflammatory diseases are accompanied by increased permeability of the epithelium, which is more susceptible to environmental triggers. Allergens and co-factors from the environment interact with innate immune receptors, such as Toll-like and protease-activated receptors on epithelial cells, stimulating them to produce cytokines that drive T-helper 2-like adaptive immunity in allergy-prone individuals. In this milieu, the next cells interacting with allergens are the dendritic cells lying just underneath the epithelium: plasmacytoid DCs, two types of conventional DCs (CD11b + and CD11b-), and monocyte-derived DCs. It is now becoming clear that CD11b+, cDCs, and moDCs are the inflammatory DCs that instruct naïve T cells to become Th2 cells. The simple paradigm of non-overlapping stable Th1 and Th2 subsets of T-helper cells is now rapidly being replaced by that of a more complex spectrum of different Th cells that together drive or control different aspects of allergic inflammation and display more plasticity in their cytokine profiles. At present, these include Th9, Th17, Th22, and Treg, in addition to Th1 and Th2. The spectrum of co-stimulatory signals coming from DCs determines which subset-characteristics will dominate. When IL-4 and/or IL-13 play a dominant role, B cells switch to IgE-production, a process that is more effective at young age. IgE-producing plasma cells have been shown to be long-lived, hiding in the bone-marrow or inflammatory tissues where they cannot easily be targeted by therapeutic intervention. Allergic sensitization is a complex interplay between the allergen in its environmental context and the tendency of the host’s innate and adaptive immune cells to be skewed towards allergic inflammation

  4. Host Cell Factors as Antiviral Targets in Arenavirus Infection

    PubMed Central

    Linero, Florencia N.; Sepúlveda, Claudia S.; Giovannoni, Federico; Castilla, Viviana; García, Cybele C.; Scolaro, Luis A.; Damonte, Elsa B.

    2012-01-01

    Among the members of the Arenaviridae family, Lassa virus and Junin virus generate periodic annual outbreaks of severe human hemorrhagic fever (HF) in endemic areas of West Africa and Argentina, respectively. Given the human health threat that arenaviruses represent and the lack of a specific and safe chemotherapy, the search for effective antiviral compounds is a continuous demanding effort. Since diverse host cell pathways and enzymes are used by RNA viruses to fulfill their replicative cycle, the targeting of a host process has turned an attractive antiviral approach in the last years for many unrelated virus types. This strategy has the additional benefit to reduce the serious challenge for therapy of RNA viruses to escape from drug effects through selection of resistant variants triggered by their high mutation rate. This article focuses on novel strategies to identify inhibitors for arenavirus therapy, analyzing the potential for antiviral developments of diverse host factors essential for virus infection. PMID:23170173

  5. [Research progress in HIV auxiliary proteins counteracting host restriction factors].

    PubMed

    Chen, Qian-Qian; Xu, Qing-Gang; Zhang, Chi-Yu

    2014-01-01

    Identification and functional analyses of antiviral restriction factors in hosts have become hot research topics. Four HIV restriction factors, APOBEC3G, Trim5alpha, Tetherin, and SAMHD1, have been identified in recent years. By encoding auxiliary proteins, lentiviruses can counteract host restriction factors. For example, the auxiliary proteins Vif, Vpu, and Vpx of HIV antagonize APOBEC3G, Tetherin, and SAMHD1, respectively. Furthermore, these auxiliary proteins enable the entry of HIV into host cells and influence the replication and pathogenicity of HIV. In this paper, we review the research progress in the functions of the three HIV auxiliary proteins that can antagonize the host restriction factors.

  6. Factors influencing host susceptibility to meningococcal disease.

    PubMed

    Winstanley, F P; Blackwell, C C; Weir, D M

    1985-01-01

    Host-parasite interactions influencing the development of the protective humoral immune response to Neisseria meningitidis are briefly reviewed. Possible consequences of the observed decreased titres of bactericidal activity specific for meningococcal serogroups A, B and C among patients with gonorrhoea are discussed with reference to: the epidemiology of the two diseases, the protective role of "natural" antibodies to the Neisseria species and the carriage rate of serogroupable strains of N. meningitidis among patients with gonorrhoea and a control population.

  7. 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

  8. Discovery of insect and human dengue virus host factors.

    PubMed

    Sessions, October M; Barrows, Nicholas J; Souza-Neto, Jayme A; Robinson, Timothy J; Hershey, Christine L; Rodgers, Mary A; Ramirez, Jose L; Dimopoulos, George; Yang, Priscilla L; Pearson, James L; Garcia-Blanco, Mariano A

    2009-04-23

    Dengue fever is the most frequent arthropod-borne viral disease of humans, with almost half of the world's population at risk of infection. The high prevalence, lack of an effective vaccine, and absence of specific treatment conspire to make dengue fever a global public health threat. Given their compact genomes, dengue viruses (DENV-1-4) and other flaviviruses probably require an extensive number of host factors; however, only a limited number of human, and an even smaller number of insect host factors, have been identified. Here we identify insect host factors required for DENV-2 propagation, by carrying out a genome-wide RNA interference screen in Drosophila melanogaster cells using a well-established 22,632 double-stranded RNA library. This screen identified 116 candidate dengue virus host factors (DVHFs). Although some were previously associated with flaviviruses (for example, V-ATPases and alpha-glucosidases), most of the DVHFs were newly implicated in dengue virus propagation. The dipteran DVHFs had 82 readily recognizable human homologues and, using a targeted short-interfering-RNA screen, we showed that 42 of these are human DVHFs. This indicates notable conservation of required factors between dipteran and human hosts. This work suggests new approaches to control infection in the insect vector and the mammalian host.

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

    PubMed

    Zheng, Yong-Hui; Jeang, Kuan-Teh; Tokunaga, Kenzo

    2012-12-20

    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.

  10. 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

  11. Host factors involved in retroviral budding and release.

    PubMed

    Martin-Serrano, Juan; Neil, Stuart J D

    2011-06-16

    The plasma membrane is the final barrier that enveloped viruses must cross during their egress from the infected cell. Here, we review recent insights into the cell biology of retroviral assembly and release; these insights have driven a new understanding of the host proteins, such as the ESCRT machinery, that are used by retroviruses to promote their final separation from the host cell. We also review antiviral host factors such as tetherin, which can directly inhibit the release of retroviral particles. These studies have illuminated the role of the lipid bilayer as the unexpected target for virus restriction by the innate immune response.

  12. Fundamental factors determining the nature of parasite aggregation in hosts.

    PubMed

    Gourbière, Sébastien; Morand, Serge; Waxman, David

    2015-01-01

    The distribution of parasites in hosts is typically aggregated: a few hosts harbour many parasites, while the remainder of hosts are virtually parasite free. The origin of this almost universal pattern is central to our understanding of host-parasite interactions; it affects many facets of their ecology and evolution. Despite this, the standard statistical framework used to characterize parasite aggregation does not describe the processes generating such a pattern. In this work, we have developed a mathematical framework for the distribution of parasites in hosts, starting from a simple statistical description in terms of two fundamental processes: the exposure of hosts to parasites and the infection success of parasites. This description allows the level of aggregation of parasites in hosts to be related to the random variation in these two processes and to true host heterogeneity. We show that random variation can generate an aggregated distribution and that the common view, that encounters and success are two equivalent filters, applies to the average parasite burden under neutral assumptions but it does not apply to the variance of the parasite burden, and it is not true when heterogeneity between hosts is incorporated in the model. We find that aggregation decreases linearly with the number of encounters, but it depends non-linearly on parasite success. We also find additional terms in the variance of the parasite burden which contribute to the actual level of aggregation in specific biological systems. We have derived the formal expressions of these contributions, and these provide new opportunities to analyse empirical data and tackle the complexity of the origin of aggregation in various host-parasite associations.

  13. A genome-wide genetic screen for host factors required for hepatitis C virus propagation

    PubMed Central

    Li, Qisheng; Brass, Abraham L.; Ng, Aylwin; Hu, Zongyi; Xavier, Ramnik J.; Liang, T. Jake; Elledge, Stephen J.

    2009-01-01

    Hepatitis C virus (HCV) infection is a major cause of end-stage liver disease and a leading indication for liver transplantation. Current therapy fails in many instances and is associated with significant side effects. HCV encodes only a few proteins and depends heavily on host factors for propagation. Each of these host dependencies is a potential therapeutic target. To find host factors required by HCV, we completed a genome-wide small interfering RNA (siRNA) screen using an infectious HCV cell culture system. We applied a two-part screening protocol to allow identification of host factors involved in the complete viral lifecycle. The candidate genes found included known or previously identified factors, and also implicate many additional host cell proteins in HCV infection. To create a more comprehensive view of HCV and host cell interactions, we performed a bioinformatic meta-analysis that integrates our data with those of previous functional and proteomic studies. The identification of host factors participating in the complete HCV lifecycle will both advance our understanding of HCV pathogenesis and illuminate therapeutic targets. PMID:19717417

  14. 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

  15. HIV suppression by host restriction factors and viral immune evasion.

    PubMed

    Jia, Xiaofei; Zhao, Qi; Xiong, Yong

    2015-04-01

    Antiviral restriction factors are an integral part of the host innate immune system that protects cells from viral pathogens, such as human immunodeficiency virus (HIV). Studies of the interactions between restriction factors and HIV have greatly advanced our understanding of both the viral life cycle and basic cell biology, as well as provided new opportunities for therapeutic intervention of viral infection. Here we review the recent developments towards establishing the structural and biochemical bases of HIV inhibition by, and viral countermeasures of, the restriction factors TRIM5, MxB, APOBEC3, SAMHD1, and BST2/tetherin.

  16. 14 CFR 1203.406 - Additional classification factors.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Additional classification factors. 1203.406... PROGRAM Guides for Original Classification § 1203.406 Additional classification factors. In determining the appropriate classification category, the following additional factors should be considered:...

  17. Shelter upgrading manual: host area shelters. Revisions and additions. Final report

    SciTech Connect

    Wilton, C.; Gabrielsen, B.L.; Tansley, R.S.

    1981-05-01

    The Shelter Upgrading Manual: Host Area Shelters, which was originally developed under Contract No. DCPA01-78-C-0215, Work Unit 1127H, is in looseleaf form to permit removal of pertinent worksheets and charts for developing upgrading plans for a specific building and to permit the addition of new and replacement material as the work progresses. The manual is one of a series being developed in support of the civil defense concept of crisis relocation planning and is designed to be used by planners in host areas. It presents a methodology for evaluating floors, roofs, and openings and develops a variety of ways to provide the necessary structural upgrading for blast and fallout protection. The revisions included here are based on a testing program and are generally in the area of modified survival ratings. Additional new material on expedient shelters is included in an appendix.

  18. The Host Specificities of Baculovirus per os Infectivity Factors.

    PubMed

    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

  19. CONTRIBUTION OF HOST-DERIVED TISSUE FACTOR TO TUMOR NEOVASCULARIZATION

    PubMed Central

    Yu, Joanne; May, Linda; Milsom, Chloe; Anderson, G. Mark; Weitz, Jeffrey I.; Luyendyk, James P.; Broze, George; Mackman, Nigel; Rak, Janusz

    2010-01-01

    Objective The role of host-derived tissue factor (TF) in tumor growth, angiogenesis and metastasis has hitherto been unclear, and was investigated in this study. Methods We compared tumor growth, vascularity and responses to cyclophosphamide (CTX) of tumors in wild type (wt) mice, or in animals with TF levels reduced by 99% (low-TF mice). Results Global growth rate of three different types of transplantable tumors (LLC, B16F1 and ES teratoma), or metastasis were unchanged in low-TF mice. However, several unexpected tumor/context-specific alterations were observed in these mice, including: (i) reduced tumor blood vessel size in B16F1 tumors; (ii) larger spleen size and greater tolerance to CTX toxicity in the LLC model; (iii) aborted tumor growth after inoculation of TF-deficient tumor cells (ES TF-/-) in low-TF mice. TF-deficient tumor cells grew readily in mice with normal TF levels, and attracted exclusively host-related blood vessels (without vasculogenic mimicry). We postulate that this complementarity may result from tumor-vascular transfer of TF-containing microvesicles, as we observed such transfer using human cancer cells (A431) and mouse endothelial cells, both in vitro and in vivo. Conclusions Our study points to an important, but context-dependent role of host TF in tumor formation, angiogenesis and therapy. PMID:18772494

  20. Hookworm virulence factors: making the most of the host.

    PubMed

    Periago, Maria V; Bethony, Jeffrey M

    2012-12-01

    Hookworm disease from Necator americanus and Ancylostoma duodenale affects approximately 700 million people, with N. americanus being the predominant species. Unlike other pathogens (e.g., bacterial infections), where "virulence" is described in regards to acute pathogenesis and case-fatality, hookworms are well-evolved, multicellular parasites that establish long-term infections in their human hosts with a subtle and chronic, but insidious, pathogenesis, usually in the form of iron deficiency anemia from parasite blood feeding that, over time, has devastating effects on the human host especially when it involves children or women of child bearing years. As such, many of the typical terms for "virulence factors" used in other reviews in this special edition cannot be applied to hookworm (e.g., "colonization", "invasion", "or "toxicity"); rather the virulence of hookworm infection comes in terms of their ability to maintain a chronic blood-feeding infection in the lumen of relatively healthy human hosts, an infection that is usually measured in years but can sometimes be measured in decades. In the current manuscript, we describe the routes of invasion hookworms take into their human hosts and the means by which they modulate the human immune system to maintain this long-term parasitism. Little data on hookworm infection comes from actual human infections; instead, much of the data is derived from observations of laboratory animal models, in which hookworms fail to establish this distinctive "chronic infection," either due to physiological or immunological responses of these animal models. Hence, the mode and effects of chronic immunity must be extrapolated from this very different sort of infection to humans. Herein, we aim to synthesize immunological information from both types of models in the context of immune regulation and protection in order to identify future research focuses for the development of new treatment alternatives (i.e. drugs and vaccines).

  1. 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

  2. 14 CFR 1203.406 - Additional classification factors.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 5 2013-01-01 2013-01-01 false Additional classification factors. 1203.406 Section 1203.406 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION INFORMATION SECURITY PROGRAM Guides for Original Classification § 1203.406 Additional classification factors. In...

  3. 14 CFR 1203.406 - Additional classification factors.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Additional classification factors. 1203.406 Section 1203.406 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION INFORMATION SECURITY PROGRAM Guides for Original Classification § 1203.406 Additional classification factors. In...

  4. 14 CFR 1203.406 - Additional classification factors.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 5 2012-01-01 2012-01-01 false Additional classification factors. 1203.406 Section 1203.406 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION INFORMATION SECURITY PROGRAM Guides for Original Classification § 1203.406 Additional classification factors. In...

  5. 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

  6. 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

  7. The DNase of gammaherpesviruses impairs recognition by virus-specific CD8+ T cells through an additional host shutoff function.

    PubMed

    Zuo, Jianmin; Thomas, Wendy; van Leeuwen, Daphne; Middeldorp, Jaap M; Wiertz, Emmanuel J H J; Ressing, Maaike E; Rowe, Martin

    2008-03-01

    The DNase/alkaline exonuclease (AE) genes are well conserved in all herpesvirus families, but recent studies have shown that the AE proteins of gammaherpesviruses such as Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) exhibit an additional function which shuts down host protein synthesis. One correlate of this additional shutoff function is that levels of cell surface HLA molecules are downregulated, raising the possibility that shutoff/AE genes of gammaherpesviruses might contribute to viral immune evasion. In this study, we show that both BGLF5 (EBV) and SOX (KSHV) shutoff/AE proteins do indeed impair the ability of virus-specific CD8+ T-cell clones to recognize endogenous antigen via HLA class I. Random mutagenesis of the BGLF5 gene enabled us to genetically separate the shutoff and AE functions and to demonstrate that the shutoff function was the critical factor determining whether BGLF5 mutants can impair T-cell recognition. These data provide further evidence that EBV has multiple mechanisms to modulate HLA class I-restricted T-cell responses, thus enabling the virus to replicate and persist in the immune-competent host.

  8. 14 CFR § 1203.406 - Additional classification factors.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 5 2014-01-01 2014-01-01 false Additional classification factors. § 1203.406 Section § 1203.406 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION INFORMATION SECURITY PROGRAM Guides for Original Classification § 1203.406 Additional classification...

  9. 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 ...

  10. Host genetic factors predisposing to HIV-associated neurocognitive disorder.

    PubMed

    Kallianpur, Asha R; Levine, Andrew J

    2014-09-01

    The success of combination antiretroviral therapy (cART) in transforming the lives of HIV-infected individuals with access to these drugs is tempered by the increasing threat of HIV-associated neurocognitive disorders (HAND) to their overall health and quality of life. Intensive investigations over the past two decades have underscored the role of host immune responses, inflammation, and monocyte-derived macrophages in HAND, but the precise pathogenic mechanisms underlying HAND remain only partially delineated. Complicating research efforts and therapeutic drug development are the sheer complexity of HAND phenotypes, diagnostic imprecision, and the growing intersection of chronic immune activation with aging-related comorbidities. Yet, genetic studies still offer a powerful means of advancing individualized care for HIV-infected individuals at risk. There is an urgent need for 1) longitudinal studies using consistent phenotypic definitions of HAND in HIV-infected subpopulations at very high risk of being adversely impacted, such as children, 2) tissue studies that correlate neuropathological changes in multiple brain regions with genomic markers in affected individuals and with changes at the RNA, epigenomic, and/or protein levels, and 3) genetic association studies using more sensitive subphenotypes of HAND. The NIH Brain Initiative and Human Connectome Project, coupled with rapidly evolving systems biology and machine learning approaches for analyzing high-throughput genetic, transcriptomic and epigenetic data, hold promise for identifying actionable biological processes and gene networks that underlie HAND. This review summarizes the current state of understanding of host genetic factors predisposing to HAND in light of past challenges and suggests some priorities for future research to advance the understanding and clinical management of HAND in the cART era. PMID:24996618

  11. A Horizontally Acquired Transcription Factor Coordinates Salmonella Adaptations to Host Microenvironments

    PubMed Central

    Rogers, Lindsay D.; Sanderson, Kristy L.; Gouw, Joost W.; Hartland, Elizabeth L.; Foster, Leonard J.

    2014-01-01

    ABSTRACT The transcription factors HilA and SsrB activate expression of two type III secretion systems (T3SSs) and cognate effectors that reprogram host cell functions to benefit infecting Salmonella in the host. These transcription factors, the secretion systems, and the effectors are all encoded by horizontally acquired genes. Using quantitative proteomics, we quantified the abundance of 2,149 proteins from hilA or ssrB Salmonella in vitro. Our results suggest that the HilA regulon does not extend significantly beyond proteins known to be involved in direct interactions with intestinal epithelium. On the other hand, SsrB influences the expression of a diverse range of proteins, many of which are ancestral to the acquisition of ssrB. In addition to the known regulon of T3SS-related proteins, we show that, through SodCI and bacterioferritin, SsrB controls resistance to reactive oxygen species and that SsrB down-regulates flagella and motility. This indicates that SsrB-controlled proteins not only redirect host cell membrane traffic to establish a supportive niche within host cells but also have adapted to the chemistry and physical constraints of that niche. PMID:25249283

  12. 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

  13. 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

  14. Evidence that the epidermal growth factor receptor on host cells confers reovirus infection efficiency.

    PubMed

    Strong, J E; Tang, D; Lee, P W

    1993-11-01

    Reovirus binds to multiple sialoglycoproteins on the host cell surface. In an attempt to probe additional specific determinants that dictate host cell susceptibility to reovirus infection, we found that two mouse cell lines (NR6 and B82) previously shown to express no endogenous epidermal growth factor (EGF) receptors were relatively resistant to reovirus infection, whereas the same cell lines transfected with the gene encoding the EGF receptor manifested significantly higher susceptibility as determined by induction of cytopathic effects, viral protein synthesis, and plaque titration. This enhancement of infection efficiency requires a functional EGF receptor since it was not observed in cells expressing a mutated (kinase-inactive) EGF receptor. The observed difference in infection efficiency is not due to differences in virus binding or internalization. These studies suggest that the reovirus infection process is closely coupled to the EGF receptor-mediated cell signal transduction pathway.

  15. 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

  16. 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

  17. Emerging functions as host cell factors - an encyclopedia of annexin-pathogen interactions.

    PubMed

    Kuehnl, Alexander; Musiol, Agnes; Raabe, Carsten A; Rescher, Ursula

    2016-10-01

    Emerging infectious diseases and drug-resistant infectious agents call for the development of innovative antimicrobial strategies. With pathogenicity now considered to arise from the complex and bi-directional interplay between a microbe and the host, host cell factor targeting has emerged as a promising approach that might overcome the limitations of classical antimicrobial drug development and could open up novel and efficient therapeutic strategies. Interaction with and modulation of host cell membranes is a recurrent theme in the host-microbe relationship. In this review, we provide an overview of what is currently known about the role of the Ca2+ dependent, membrane-binding annexin protein family in pathogen-host interactions, and discuss their emerging functions as host cell derived auxiliary proteins in microbe-host interactions and host cell targets.

  18. 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

  19. Identifying host genetic risk factors in the context of public health surveillance for invasive pneumococcal disease.

    PubMed

    Lingappa, Jairam R; Dumitrescu, Logan; Zimmer, Shanta M; Lynfield, Ruth; McNicholl, Janet M; Messonnier, Nancy E; Whitney, Cynthia G; Crawford, Dana C

    2011-01-01

    Host genetic factors that modify risk of pneumococcal disease may help target future public health interventions to individuals at highest risk of disease. We linked data from population-based surveillance for invasive pneumococcal disease (IPD) with state-based newborn dried bloodspot repositories to identify biological samples from individuals who developed invasive pneumococcal disease. Genomic DNA was extracted from 366 case and 732 anonymous control samples. TagSNPs were selected in 34 candidate genes thought to be associated with host response to invasive pneumococcal disease, and a total of 326 variants were successfully genotyped. Among 543 European Americans (EA) (182 cases and 361 controls), and 166 African Americans (AA) (53 cases and 113 controls), common variants in surfactant protein D (SFTPD) are consistently underrepresented in IPD. SFTPD variants with the strongest association for IPD are intronic rs17886286 (allelic OR 0.45, 95% confidence interval (CI) [0.25, 0.82], with p = 0.007) in EA and 5' flanking rs12219080 (allelic OR 0.32, 95%CI [0.13, 0.78], with p = 0.009) in AA. Variants in CD46 and IL1R1 are also associated with IPD in both EA and AA, but with effects in different directions; FAS, IL1B, IL4, IL10, IL12B, SFTPA1, SFTPB, and PTAFR variants are associated (p≤0.05) with IPD in EA or AA. We conclude that variants in SFTPD may protect against IPD in EA and AA and genetic variation in other host response pathways may also contribute to risk of IPD. While our associations are not corrected for multiple comparisons and therefore must be replicated in additional cohorts, this pilot study underscores the feasibility of integrating public health surveillance with existing, prospectively collected, newborn dried blood spot repositories to identify host genetic factors associated with infectious diseases.

  20. 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

  1. 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

  2. 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.

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

    PubMed

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

    2015-12-01

    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.

  4. The Golgi associated ERI3 is a Flavivirus host factor

    PubMed Central

    Ward, Alex Michael; Calvert, Meredith E. K.; Read, Leah R.; Kang, Seokyoung; Levitt, Brandt E.; Dimopoulos, George; Bradrick, Shelton S.; Gunaratne, Jayantha; Garcia-Blanco, Mariano A.

    2016-01-01

    Dengue virus (DENV) is a mosquito-borne Flavivirus classified into four serotypes (DENV-1-4) that causes Dengue fever (DF), Dengue hemorrhagic Fever (DHF) or Dengue shock syndrome (DSS). An estimated 390 million people are at risk for infection with DENV and there are no effective vaccines or therapeutics. We utilized RNA chromatography coupled with quantitative mass spectrometry (qMS) to identify host RNA binding proteins (RBPs) that interact with DENV-2 RNA. We identified ERI3 (also PRNPIP and PINT1), a putative 3′–5′ RNA exonuclease, which preferentially associates with DENV-2 genomic RNA via interactions with dumbbell structures in the 3′ UTR. ERI3 is required for accumulation of DENV-2 genomic RNA and production of infectious particles. Furthermore, the mosquito homologue of ERI3 is required for DENV-2 replication in adult Aedes aegypti mosquitos implying that the requirement for ERI3 is conserved in both DENV hosts. In human cells ERI3 localizes to the Golgi in uninfected cells, but relocalizes near sites of DENV-2 replication in infected cells. ERI3 is not required for maintaining DENV-2 RNA stability or translation of the viral polyprotein, but is required for viral RNA synthesis. Our results define a specific role for ERI3 and highlight the importance of Golgi proteins in DENV-2 replication. PMID:27682269

  5. Bacterial meningitis in the patient at risk: intrinsic risk factors and host defense mechanisms.

    PubMed

    Scheld, W M

    1984-05-15

    Bacterial meningitis remains a relatively common disease worldwide (40,000 cases per year in the United States) and the mortality rate has not improved in over 30 years. Certain host factors increase the risk of acquiring meningitis and include: age (increased at extremes of life), male sex, low socioeconomic status (crowding), black race, recent nasopharyngeal carriage of a virulent strain, absence of specific bactericidal antibody, maternal factors at birth (neonatal disease), various immunologic defects (neonates, antibody or terminal complement component deficiency, splenectomy, and immunosuppression including the acquired immune deficiency syndrome), and certain chronic diseases (such as alcoholism, cirrhosis, and diabetes mellitus). Bacterial meningitis represents an infection in an area of impaired host resistance. The blood-brain barrier is a major protective mechanism for the central nervous system against circulating bacteria. However, once bacteria gain entry into the subarachnoid space, host defenses are inadequate. Polymorphonuclear leukocytes are at a disadvantage in the fluid medium of the cerebrospinal fluid and surface phagocytosis is inefficient. In addition, antibody and complement concentrations are low (or absent) in purulent cerebrospinal fluid early in the disease course. Functional opsonic and bactericidal activity is lacking; therefore, efficient phagocytosis of encapsulated meningeal pathogens is limited. The result is huge population densities (often 10(7) to 10(8) cfu per milliliter) of bacteria in cerebrospinal fluid. This finding suggests that bactericidal antibiotics with cerebrospinal fluid concentrations much greater than the minimal bacterial concentration of the pathogen are optimal for therapy of meningitis; this principle has been shown in experimental animal models and supported by therapeutic studies in human subjects.

  6. 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

  7. 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

  8. [Host and environmental factors predisposing to cancer development].

    PubMed

    Kono, Suminori

    2010-04-01

    Descriptive epidemiology, particularly regarding the cancer pattern in Japanese and Koreans in the United States, indicates that lifestyle factors contribute substantially to the development of common cancers such as gastric, colorectal, breast and prostate cancers. Sex and age are important determinants of many cancers, and the variation in cancer incidence according to these factors is also indicative of the role of environmental factors. While cancer of first-degree relatives or parental cancer was related to an approximately 2-fold increased risk for most site-specific cancers, a large Scandinavian twin study suggested that the contribution of genetic factors was generally small and that a statistically significant effect of hereditable factors was observed only for prostate, colorectal and breast cancers. It was roughly estimated in this article that infectious agents contributed to 20% of incident cases of cancer in Japan. In a recent cohort study in Japan, it is estimated that 29% of male cancers and 3% of female cancers can be ascribed to smoking. Among other lifestyle factors, alcohol consumption and obesity have provided convincing evidence as factors conferring increased risks of various cancers. The increased risks of colorectal cancer and breast cancer associated with alcohol drinking have been recently acknowledged internationally. Among dietary factors, red meat, aflatoxin and beta-carotene are considered to increase risks of colorectal, liver and lung cancers, respectively. Vegetables and fruits probably decrease the risk of cancer at various sites, and calcium specifically decreases the risk of colorectal cancer. Evidence for increased risk of gastric cancer associated with salted foods is judged to be not sufficient, although a high-salt diet enhanced gastric cancer in animals infected with Helicobacter pylori. The role of dietary factors in cancer development will be more clearly established by research on gene-environment interaction focusing on

  9. 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

  10. 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

  11. 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.

  12. 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.

  13. Genetic risk factors for sclerotic graft-versus-host disease.

    PubMed

    Inamoto, Yoshihiro; Martin, Paul J; Flowers, Mary E D; Lee, Stephanie J; Carpenter, Paul A; Warren, Edus H; Geraghty, Daniel E; Lee, Ni; Boeckh, Michael J; Storer, Barry E; Levine, David M; Fan, Wenhong; Zhao, Lue-Ping; Hansen, John A

    2016-09-15

    Sclerotic graft-versus-host disease (GVHD) is a distinctive phenotype of chronic GVHD after allogeneic hematopoietic cell transplantation, characterized by fibrosis of skin or fascia. Sclerotic GVHD has clinical and histopathological similarities with systemic sclerosis, an autoimmune disease whose risk is influenced by genetic polymorphisms. We examined 13 candidate single-nucleotide polymorphisms (SNPs) that have a well-documented association with systemic sclerosis to determine whether these SNPs are also associated with the risk of sclerotic GVHD. The study cohort included 847 consecutive patients who were diagnosed with chronic GVHD. Genotyping was performed using microarrays, followed by imputation of unobserved SNPs. The donor rs10516487 (BANK1: B-cell scaffold protein with ankyrin repeats 1) TT genotype was associated with lower risk of sclerotic GVHD (hazard ratio [HR], 0.43; 95% confidence interval [CI], 0.21-0.87; P = .02). Donor and recipient rs2056626 (CD247: T-cell receptor ζ subunit) GG or GT genotypes were associated with higher risk of sclerotic GVHD (HR, 1.57; 95% CI, 1.13-2.18; P = .007 and HR, 1.66; 95% CI, 1.19-2.32; P = .003, respectively). Donor and recipient rs987870 (5'-flanking region of HLA-DPA1) CC genotypes were associated with higher risk of sclerotic GVHD (HR, 2.50; 95% CI, 1.22-5.11; P = .01 and HR, 2.13; 95% CI, 1.00-4.54; P = .05, respectively). In further analyses, the recipient DPA1*01:03∼DPB1*04:01 haplotype and certain amino acid substitutions in the recipient P1 peptide-binding pocket of the HLA-DP heterodimer were associated with risk of sclerotic GVHD. Genetic components associated with systemic sclerosis are also associated with sclerotic GVHD. HLA-DP-mediated antigen presentation, T-cell response, and B-cell activation have important roles in the pathogenic mechanisms of both diseases. PMID:27313329

  14. SAMHD1 host restriction factor: a link with innate immune sensing of retrovirus infection.

    PubMed

    Sze, Alexandre; Olagnier, David; Lin, Rongtuan; van Grevenynghe, Julien; Hiscott, John

    2013-12-13

    SAMHD1 [sterile alpha motif and histidine-aspartic domain (HD) containing protein 1] is the most recent addition to a unique group of host restriction factors that limit retroviral replication at distinct stages of the viral life cycle. SAMHD1 is a deoxynucleoside triphosphate triphosphohydrolase that degrades the intracellular pool of deoxynucleoside triphosphates available during early reverse transcription. SAMHD1 activity is blocked by the Vpx accessory function present in human immunodeficiency virus type 2 and SIVsm. Mutations in SAMHD1 are associated with the autoimmune disorder Aicardi-Goutières syndrome, thus emphasizing its role in regulation of the immune response. SAMHD1 antiretroviral activity is modulated by post-translational modifications, cell-cycle-dependent functions and cytokine-mediated changes. Innate receptors that sense retroviral DNA intermediates are the focus of intense study, and recent studies have established a link among SAMHD1 restriction, innate sensing of DNA and protective immune responses. Cell-cycle-dependent regulation of SAMHD1 by phosphorylation and the increasingly broad range of viruses inhibited by SAMHD1 further emphasize the importance of these mechanisms of host restriction. This review highlights current knowledge regarding SAMHD1 regulation and its impact on innate immune signaling and retroviral restriction.

  15. 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.

  16. 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

  17. 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

  18. 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

  19. 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.

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

    PubMed Central

    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. The Macrophage Migration Inhibitory Factor Homolog of Entamoeba histolytica Binds to and Immunomodulates Host Macrophages

    PubMed Central

    Moonah, Shannon N.; Abhyankar, Mayuresh M.; Haque, Rashidul

    2014-01-01

    The host inflammatory response contributes to the tissue damage that occurs during amebic colitis, with tumor necrosis factor alpha (TNF-α) being a key mediator of the gut inflammation observed. Mammalian macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that plays an important role in the exacerbation of a wide range of inflammatory diseases, including colitis. We identified a MIF gene homolog in the Entamoeba histolytica genome, raising the question of whether E. histolytica MIF (EhMIF) has proinflammatory activity similar to that of mammalian MIF. In this report, we describe the first functional characterization of EhMIF. Antibodies were prepared against recombinantly expressed EhMIF and used to demonstrate that EhMIF is expressed as a 12-kDa protein localized to the cytoplasm of trophozoites. In a manner similar to that of mammalian MIF, EhMIF interacted with the MIF receptor CD74 and bound to macrophages. EhMIF induced interleukin-6 (IL-6) production. In addition, EhMIF enhanced TNF-α secretion by amplifying TNF-α production by lipopolysaccharide (LPS)-stimulated macrophages and by inhibiting the glucocorticoid-mediated suppression of TNF-α secretion. EhMIF was expressed during human infection, as evidenced by the presence of anti-EhMIF antibodies in the sera of children living in an area where E. histolytica infection is endemic. Anti-EhMIF antibodies did not cross-react with human MIF. The ability of EhMIF to modulate host macrophage function may promote an exaggerated proinflammatory immune response and contribute to the tissue damage seen in amebic colitis. PMID:24818664

  2. A loss of function analysis of host factors influencing Vaccinia virus replication by RNA interference.

    PubMed

    Beard, Philippa M; Griffiths, Samantha J; Gonzalez, Orland; Haga, Ismar R; Pechenick Jowers, Tali; Reynolds, Danielle K; Wildenhain, Jan; Tekotte, Hille; Auer, Manfred; Tyers, Mike; Ghazal, Peter; Zimmer, Ralf; Haas, Jürgen

    2014-01-01

    Vaccinia virus (VACV) is a large, cytoplasmic, double-stranded DNA virus that requires complex interactions with host proteins in order to replicate. To explore these interactions a functional high throughput small interfering RNA (siRNA) screen targeting 6719 druggable cellular genes was undertaken to identify host factors (HF) influencing the replication and spread of an eGFP-tagged VACV. The experimental design incorporated a low multiplicity of infection, thereby enhancing detection of cellular proteins involved in cell-to-cell spread of VACV. The screen revealed 153 pro- and 149 anti-viral HFs that strongly influenced VACV replication. These HFs were investigated further by comparisons with transcriptional profiling data sets and HFs identified in RNAi screens of other viruses. In addition, functional and pathway analysis of the entire screen was carried out to highlight cellular mechanisms involved in VACV replication. This revealed, as anticipated, that many pro-viral HFs are involved in translation of mRNA and, unexpectedly, suggested that a range of proteins involved in cellular transcriptional processes and several DNA repair pathways possess anti-viral activity. Multiple components of the AMPK complex were found to act as pro-viral HFs, while several septins, a group of highly conserved GTP binding proteins with a role in sequestering intracellular bacteria, were identified as strong anti-viral VACV HFs. This screen has identified novel and previously unexplored roles for cellular factors in poxvirus replication. This advancement in our understanding of the VACV life cycle provides a reliable knowledge base for the improvement of poxvirus-based vaccine vectors and development of anti-viral theraputics.

  3. 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

  4. 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

  5. Genetic study of host factors in gastrocarcinogenesis in rats.

    PubMed

    Morino, K; Ohgaki, H; Matsukura, N; Kawachi, T; Sugimura, T

    1982-01-01

    The effects of genetic factors on gastrocarcinogenesis in rats were studied by giving 83 micrograms/ml of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in the drinking-water to ACI strain rats, Buffalo strain rats, and their F1 hybrid rats for eight months. Animals were sacrificed on the 505th experimental day and examined histologically. The incidences of gastric carcinoma were as follows (no. of carcinoma-bearing rats/no. of effective animals): ACI rats, 86% (12/14) of males and 53% (9/17) of females; Buffalo rats, 19% (3/16) of males and 0% (0/13) of females; F1 hybrids between ACI and Buffalo rats, 23% (7/30) of males and 3% (1/32) of females. The incidence of gastric carcinoma in F1 hybrids was significantly lower than that in ACI rats but not significantly different from that in Buffalo rats. These results suggest that resistance to gastrocarcinogenesis by MNNG is an autosomally dominant trait.

  6. 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...

  7. Functional analysis of host factors that mediate the intracellular lifestyle of Cryptococcus neoformans.

    PubMed

    Qin, Qing-Ming; Luo, Jijing; Lin, Xiaorong; Pei, Jianwu; Li, Lei; Ficht, Thomas A; de Figueiredo, Paul

    2011-06-01

    Cryptococcus neoformans (Cn), the major causative agent of human fungal meningoencephalitis, replicates within phagolysosomes of infected host cells. Despite more than a half-century of investigation into host-Cn interactions, host factors that mediate infection by this fungal pathogen remain obscure. Here, we describe the development of a system that employs Drosophila S2 cells and RNA interference (RNAi) to define and characterize Cn host factors. The system recapitulated salient aspects of fungal interactions with mammalian cells, including phagocytosis, intracellular trafficking, replication, cell-to-cell spread and escape of the pathogen from host cells. Fifty-seven evolutionarily conserved host factors were identified using this system, including 29 factors that had not been previously implicated in mediating fungal pathogenesis. Subsequent analysis indicated that Cn exploits host actin cytoskeletal elements, cell surface signaling molecules, and vesicle-mediated transport proteins to establish a replicative niche. Several host molecules known to be associated with autophagy (Atg), including Atg2, Atg5, Atg9 and Pi3K59F (a class III PI3-kinase) were also uncovered in our screen. Small interfering RNA (siRNA) mediated depletion of these autophagy proteins in murine RAW264.7 macrophages demonstrated their requirement during Cn infection, thereby validating findings obtained using the Drosophila S2 cell system. Immunofluorescence confocal microscopy analyses demonstrated that Atg5, LC3, Atg9a were recruited to the vicinity of Cn containing vacuoles (CnCvs) in the early stages of Cn infection. Pharmacological inhibition of autophagy and/or PI3-kinase activity further demonstrated a requirement for autophagy associated host proteins in supporting infection of mammalian cells by Cn. Finally, systematic trafficking studies indicated that CnCVs associated with Atg proteins, including Atg5, Atg9a and LC3, during trafficking to a terminal intracellular compartment that

  8. 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

  9. 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

  10. Biogeography and host-related factors trump parasite life history: limited congruence among the genetic structures of specific ectoparasitic lice and their rodent hosts.

    PubMed

    du Toit, Nina; van Vuuren, Bettine J; Matthee, Sonja; Matthee, Conrad A

    2013-10-01

    Parasites and hosts interact across both micro- and macroevolutionary scales where congruence among their phylogeographic and phylogenetic structures may be observed. Within southern Africa, the four-striped mouse genus, Rhabdomys, is parasitized by the ectoparasitic sucking louse, Polyplax arvicanthis. Molecular data recently suggested the presence of two cryptic species within P. arvicanthis that are sympatrically distributed across the distributions of four putative Rhabdomys species. We tested the hypotheses of phylogeographic congruence and cophylogeny among the two parasite lineages and the four host taxa, utilizing mitochondrial and nuclear sequence data. Despite the documented host-specificity of P. arvicanthis, limited phylogeographic correspondence and nonsignificant cophylogeny was observed. Instead, the parasite-host evolutionary history is characterized by limited codivergence and several duplication, sorting and host-switching events. Despite the elevated mutational rates found for P. arvicanthis, the spatial genetic structure was not more pronounced in the parasite lineages compared with the hosts. These findings may be partly attributed to larger effective population sizes of the parasite lineages, the vagility and social behaviour of Rhabdomys, and the lack of host-specificity observed in areas of host sympatry. Further, the patterns of genetic divergence within parasite and host lineages may also be largely attributed to historical biogeographic changes (expansion-contraction cycles). It is thus evident that the association between P. arvicanthis and Rhabdomys has been shaped by the synergistic effects of parasite traits, host-related factors and biogeography over evolutionary time.

  11. 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

  12. 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

  13. Identification of novel host factors via conserved domain search: Cns1 cochaperone is a novel restriction factor of tombusvirus replication in yeast.

    PubMed

    Lin, Jing-Yi; Nagy, Peter D

    2013-12-01

    A large number of host-encoded proteins affect the replication of plus-stranded RNA viruses by acting as susceptibility factors. Many other cellular proteins are known to function as restriction factors of viral infections. Previous studies with tomato bushy stunt tombusvirus (TBSV) in a yeast model host have revealed the inhibitory function of TPR (tetratricopeptide repeat) domain-containing cyclophilins, which are members of the large family of host prolyl isomerases, in TBSV replication. In this paper, we tested additional TPR-containing yeast proteins in a cell-free TBSV replication assay and identified the Cns1p cochaperone for heat shock protein 70 (Hsp70) and Hsp90 chaperones as a strong inhibitor of TBSV replication. Cns1p interacted with the viral replication proteins and inhibited the assembly of the viral replicase complex and viral RNA synthesis in vitro. Overexpression of Cns1p inhibited TBSV replication in yeast. The use of a temperature-sensitive (TS) mutant of Cns1p in yeast revealed that at a semipermissive temperature, TS Cns1p could not inhibit TBSV replication. Interestingly, Cns1p and the TPR-containing Cpr7p cyclophilin have similar inhibitory functions during TBSV replication, although some of the details of their viral restriction mechanisms are different. Our observations indicate that TPR-containing cellular proteins could act as virus restriction factors. PMID:24027337

  14. Human genome-wide RNAi screen reveals host factors required for enterovirus 71 replication

    PubMed Central

    Wu, Kan Xing; Phuektes, Patchara; Kumar, Pankaj; Goh, Germaine Yen Lin; Moreau, Dimitri; Chow, Vincent Tak Kwong; Bard, Frederic; Chu, Justin Jang Hann

    2016-01-01

    Enterovirus 71 (EV71) is a neurotropic enterovirus without antivirals or vaccine, and its host-pathogen interactions remain poorly understood. Here we use a human genome-wide RNAi screen to identify 256 host factors involved in EV71 replication in human rhabdomyosarcoma cells. Enrichment analyses reveal overrepresentation in processes like mitotic cell cycle and transcriptional regulation. We have carried out orthogonal experiments to characterize the roles of selected factors involved in cell cycle regulation and endoplasmatic reticulum-associated degradation. We demonstrate nuclear egress of CDK6 in EV71 infected cells, and identify CDK6 and AURKB as resistance factors. NGLY1, which co-localizes with EV71 replication complexes at the endoplasmatic reticulum, supports EV71 replication. We confirm importance of these factors for EV71 replication in a human neuronal cell line and for coxsackievirus A16 infection. A small molecule inhibitor of NGLY1 reduces EV71 replication. This study provides a comprehensive map of EV71 host factors and reveals potential antiviral targets. PMID:27748395

  15. Identification of host factors that regulate the influenza virus RNA polymerase activity.

    PubMed

    Momose, F; Handa, H; Nagata, K

    1996-01-01

    Transcription and replication of the influenza virus RNA genome take place in the nuclei of infected cells. Ribonucleoprotein (RNP) complexes consisting of viral RNA, RNA polymerase, and nucleocapsid protein (NP) are proven to be the catalytic unit for RNA synthesis, while it has been indicated that the viral RNA polymerase activity is modulated by host-derived nuclear factors. Here we have identified such host factors present in nuclear extracts prepared from uninfected HeLa cells with biochemical complementation assays using the in vitro RNA synthesis system. The stimulatory activity was not absorbed to phosphocellulose but was tightly bound to Q-Sepharose. The eluate recovered from Q-Sepharose was able to stimulate the RNA synthesis catalyzed by both RNP complexes and purified RNA polymerase and NP. The stimulatory activity was further separated into two distinct fractions, designated RAF-1 (RNA polymerase activating factor-1) and RAF-2 fractions, through phenyl-Sepharose column chromatography. When these fractions were fractionated through a gel filtration column, RAF-1 and RAF-2 activities were recovered in fractions corresponding to the molecular mass of 350 kDa and 60 kDa, respectively. Furthermore, the RAF-2 fraction was shown to contain an inhibitory activity, tentatively designated RIF-1 (RNA polymerase inhibitory factor-1). RIF-1 sedimented as fast as bovine serum albumin in glycerol density gradient centrifugation. Roles of these host factors are discussed in the context of viral RNA transcription and replication.

  16. 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

  17. Drosophila host model reveals new enterococcus faecalis quorum-sensing associated virulence factors.

    PubMed

    Teixeira, Neuza; Varahan, Sriram; Gorman, Matthew J; Palmer, Kelli L; Zaidman-Remy, Anna; Yokohata, Ryoji; Nakayama, Jiro; Hancock, Lynn E; Jacinto, António; Gilmore, Michael S; de Fátima Silva Lopes, Maria

    2013-01-01

    Enterococcus faecalis V583 is a vancomycin-resistant clinical isolate which belongs to the hospital-adapted clade, CC2. This strain harbours several factors that have been associated with virulence, including the fsr quorum-sensing regulatory system that is known to control the expression of GelE and SprE proteases. To discriminate between genes directly regulated by Fsr, and those indirectly regulated as the result of protease expression or activity, we compared gene expression in isogenic mutants of V583 variously defective in either Fsr quorum sensing or protease expression. Quorum sensing was artificially induced by addition of the quorum signal, GBAP, exogenously in a controlled manner. The Fsr regulon was found to be restricted to five genes, gelE, sprE, ef1097, ef1351 and ef1352. Twelve additional genes were found to be dependent on the presence of GBAP-induced proteases. Induction of GelE and SprE by GBAP via Fsr resulted in accumulation of mRNA encoding lrgAB, and this induction was found to be lytRS dependent. Drosophila infection was used to discern varying levels of toxicity stemming from mutations in the fsr quorum regulatory system and the genes that it regulates, highlighting the contribution of LrgAB and bacteriocin EF1097 to infection toxicity. A contribution of SprE to infection toxicity was also detected. This work brought to light new players in E. faecalis success as a pathogen and paves the way for future studies on host tolerance mechanisms to infections caused by this important nosocomial pathogen.

  18. 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

  19. 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

  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. 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

  2. The Cryptococcus neoformans Rim101 Transcription Factor Directly Regulates Genes Required for Adaptation to the Host

    PubMed Central

    O'Meara, Teresa R.; Xu, Wenjie; Selvig, Kyla M.; O'Meara, Matthew J.; Mitchell, Aaron P.

    2014-01-01

    The Rim101 protein is a conserved pH-responsive transcription factor that mediates important interactions between several fungal pathogens and the infected host. In the human fungal pathogen Cryptococcus neoformans, the Rim101 protein retains conserved functions to allow the microorganism to respond to changes in pH and other host stresses. This coordinated cellular response enables this fungus to effectively evade the host immune response. Preliminary studies suggest that this conserved transcription factor is uniquely regulated in C. neoformans both by the canonical pH-sensing pathway and by the cyclic AMP (cAMP)/protein kinase A (PKA) pathway. Here we present comparative transcriptional data that demonstrate a strong concordance between the downstream effectors of PKA and Rim101. To define Rim101-dependent gene expression during a murine lung infection, we used nanoString profiling of lung tissue infected with a wild-type or rim101Δ mutant strain. In this setting, we demonstrated that Rim101 controls the expression of multiple cell wall-biosynthetic genes, likely explaining the enhanced immunogenicity of the rim101Δ mutant. Despite its divergent upstream regulation, the C. neoformans Rim101 protein recognizes a conserved DNA binding motif. Using these data, we identified direct targets of this transcription factor, including genes involved in cell wall regulation. Therefore, the Rim101 protein directly controls cell wall changes required for the adaptation of C. neoformans to its host environment. Moreover, we propose that integration of the cAMP/PKA and pH-sensing pathways allows C. neoformans to respond to a broad range of host-specific signals. PMID:24324006

  3. Dengue virus therapeutic intervention strategies based on viral, vector and host factors involved in disease pathogenesis.

    PubMed

    Herrero, Lara J; Zakhary, Andrew; Gahan, Michelle E; Nelson, Michelle A; Herring, Belinda L; Hapel, Andrew J; Keller, Paul A; Obeysekera, Maheshi; Chen, Weiqiang; Sheng, Kuo-Ching; Taylor, Adam; Wolf, Stefan; Bettadapura, Jayaram; Broor, Shobha; Dar, Lalit; Mahalingam, Suresh

    2013-02-01

    Dengue virus (DV) is the most widespread arbovirus, being endemic in over 100 countries, and is estimated to cause 50 million infections annually. Viral factors, such as the genetic composition of the virus strain can play a role in determining the virus virulence and subsequent clinical disease severity. Virus vector competence plays an integral role in virus transmission and is a critical factor in determining the severity and impact of DV outbreaks. Host genetic variations in immune-related genes, including the human leukocyte antigen, have also been shown to correlate with clinical disease and thus may play a role in regulating disease severity. The host's immune system, however, appears to be the primary factor in DV pathogenesis with the delicate interplay of innate and acquired immunity playing a crucial role. Although current research of DV pathogenesis has been limited by the lack of an appropriate animal model, the development of DV therapeutics has been a primary focus of research groups around the world. In the past decade advances in both the development of vaccines and anti-virals have increased in dramatically. This review summarises the current understanding of viral, vector and host factors which contribute to dengue virus pathogenesis and how this knowledge is critically important in the development of pharmaceutical interventions. PMID:23103333

  4. Interleukin-22 and CD160 play additive roles in the host mucosal response to Clostridium difficile infection in mice

    PubMed Central

    Sadighi Akha, Amir A; McDermott, Andrew J; Theriot, Casey M; Carlson, Paul E; Frank, Charles R; McDonald, Roderick A; Falkowski, Nicole R; Bergin, Ingrid L; Young, Vincent B; Huffnagle, Gary B

    2015-01-01

    Our previous work has shown the significant up-regulation of Il22 and increased phosphorylation of signal transducer and activator of transcription 3 (STAT3) as part of the mucosal inflammatory response to Clostridium difficile infection in mice. Others have shown that phosphorylation of STAT3 at mucosal surfaces includes interleukin-22 (IL-22) and CD160-mediated components. The current study sought to determine the potential role(s) of IL-22 and/or CD160 in the mucosal response to C. difficile infection. Clostridium difficile-infected mice treated with anti-IL-22, anti-CD160 or a combination of the two showed significantly reduced STAT3 phosphorylation in comparison to C. difficile-infected mice that had not received either antibody. In addition, C. difficile-infected mice treated with anti-IL-22/CD160 induced a smaller set of genes, and at significantly lower levels than the untreated C. difficile-infected mice. The affected genes included pro-inflammatory chemokines and cytokines, and anti-microbial peptides. Furthermore, histopathological and flow cytometric assessments both showed a significantly reduced influx of neutrophils in C. difficile-infected mice treated with anti-IL-22/CD160. These data demonstrate that IL-22 and CD160 are together responsible for a significant fraction of the colonic STAT3 phosphorylation in C. difficile infection. They also underscore the additive effects of IL-22 and CD160 in mediating both the pro-inflammatory and pro-survival aspects of the host mucosal response in this infection. PMID:25327211

  5. 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

  6. 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

  7. Additions to the Encyrtidae and Mymaridae (Chalcidoidea) of India with new distribution and host records for some species

    PubMed Central

    Rameshkumar, A.; V, Naveen

    2015-01-01

    Abstract Background Encyrtidae and Mymaridae of India have not been surveyed in depth and hosts are not known for most of the species as the methods of collections used are passive and do not yield firsthand information on the hosts. Based on our ongoing surveys on the Encyrtidae and Mymaridae of India, we report here new distribution and host records for some species. New information Acmopolynema campylurum Xu and Lin, Litus cynipseus Haliday, Omyomymar glabrum Lin and Chiappini and Platystethynium Ogloblin (Mymaridae), and Rhytidothorax purpureiscutellum (Girault) (Encyrtidae) are reported for the first time from India. Anagyrus aquilonaris (Noyes and Hayat) is recorded as new to Arunachal Pradesh and Meghalaya. Paraphaenodiscus indicus Singh and Agarwal and Paraphaenodiscus monawari Bhuiya are recorded from south India for the first time, the latter on a new host, Pulvinaria polygonata. Chorizococcus sorghi Williams (Pseudococcidae) is reported as a host for Cryptanusia ajmerensis (Fatma & Shafee), for which no hosts are hitherto known and the male of Cryptanusia is documented for the first time. Aclerda sp. is recorded as a new host for Neastymachus axillaris Singh, Agarwal and Basha. PMID:26069438

  8. 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.

  9. 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.

  10. Gut Microbiome and Infant Health: Brain-Gut-Microbiota Axis and Host Genetic Factors

    PubMed Central

    Cong, Xiaomei; Xu, Wanli; Romisher, Rachael; Poveda, Samantha; Forte, Shaina; Starkweather, Angela; Henderson, Wendy A.

    2016-01-01

    The development of the neonatal gut microbiome is influenced by multiple factors, such as delivery mode, feeding, medication use, hospital environment, early life stress, and genetics. The dysbiosis of gut microbiota persists during infancy, especially in high-risk preterm infants who experience lengthy stays in the Neonatal intensive care unit (NICU). Infant microbiome evolutionary trajectory is essentially parallel with the host (infant) neurodevelopmental process and growth. The role of the gut microbiome, the brain-gut signaling system, and its interaction with the host genetics have been shown to be related to both short and long term infant health and bio-behavioral development. The investigation of potential dysbiosis patterns in early childhood is still lacking and few studies have addressed this host-microbiome co-developmental process. Further research spanning a variety of fields of study is needed to focus on the mechanisms of brain-gut-microbiota signaling system and the dynamic host-microbial interaction in the regulation of health, stress and development in human newborns. PMID:27698614

  11. Gut Microbiome and Infant Health: Brain-Gut-Microbiota Axis and Host Genetic Factors

    PubMed Central

    Cong, Xiaomei; Xu, Wanli; Romisher, Rachael; Poveda, Samantha; Forte, Shaina; Starkweather, Angela; Henderson, Wendy A.

    2016-01-01

    The development of the neonatal gut microbiome is influenced by multiple factors, such as delivery mode, feeding, medication use, hospital environment, early life stress, and genetics. The dysbiosis of gut microbiota persists during infancy, especially in high-risk preterm infants who experience lengthy stays in the Neonatal intensive care unit (NICU). Infant microbiome evolutionary trajectory is essentially parallel with the host (infant) neurodevelopmental process and growth. The role of the gut microbiome, the brain-gut signaling system, and its interaction with the host genetics have been shown to be related to both short and long term infant health and bio-behavioral development. The investigation of potential dysbiosis patterns in early childhood is still lacking and few studies have addressed this host-microbiome co-developmental process. Further research spanning a variety of fields of study is needed to focus on the mechanisms of brain-gut-microbiota signaling system and the dynamic host-microbial interaction in the regulation of health, stress and development in human newborns.

  12. Affinity Capture and Identification of Host Cell Factors Associated with Hepatitis C Virus (+) Strand Subgenomic RNA*

    PubMed Central

    Upadhyay, Alok; Dixit, Updesh; Manvar, Dinesh; Chaturvedi, Nootan; Pandey, Virendra N.

    2013-01-01

    Hepatitis C virus (HCV) infection leading to chronic hepatitis is a major factor in the causation of liver cirrhosis, hepatocellular carcinoma, and liver failure. This process may involve the interplay of various host cell factors, as well as the interaction of these factors with viral RNA and proteins. We report a novel strategy using a sequence-specific biotinylated peptide nucleic acid (PNA)-neamine conjugate targeted to HCV RNA for the in situ capture of subgenomic HCV (+) RNA, along with cellular and viral factors associated with it in MH14 host cells. Using this affinity capture system in conjunction with LC/MS/MS, we have identified 83 cellular factors and three viral proteins (NS5B, NS5A, and NS3–4a protease-helicase) associated with the viral genome. The capture was highly specific. These proteins were not scored with cured MH14 cells devoid of HCV replicons because of the absence of the target sequence in cells for the PNA-neamine probe and also because, unlike oligomeric DNA, cellular proteins have no affinity for PNA. The identified cellular factors belong to different functional groups, including signaling, oncogenic, chaperonin, transcriptional regulators, and RNA helicases as well as DEAD box proteins, ribosomal proteins, translational regulators/factors, and metabolic enzymes, that represent a diverse set of cellular factors associated with the HCV RNA genome. Small interfering RNA-mediated silencing of a diverse class of selected proteins in an HCV replicon cell line either enhanced or inhibited HCV replication/translation, suggesting that these cellular factors have regulatory roles in HCV replication. PMID:23429521

  13. Helicobacter pylori virulence genes and host genetic polymorphisms as risk factors for peptic ulcer disease.

    PubMed

    Miftahussurur, Muhammad; Yamaoka, Yoshio

    2015-01-01

    Helicobacter pylori infection plays an important role in the pathogenesis of peptic ulcer disease (PUD). Several factors have been proposed as possible H. pylori virulence determinants; for example, bacterial adhesins and gastric inflammation factors are associated with an increased risk of PUD. However, differences in bacterial virulence factors alone cannot explain the opposite ends of the PUD disease spectrum, that is duodenal and gastric ulcers; presumably, both bacterial and host factors contribute to the differential response. Carriers of the high-producer alleles of the pro-inflammatory cytokines IL-1B, IL-6, IL-8, IL-10, and TNF-α who also carry low-producer allele of anti-inflammatory cytokines have severe gastric mucosal inflammation, whereas carriers of the alternative alleles have mild inflammation. Recent reports have suggested that the PSCA and CYP2C19 ultra-rapid metabolizer genotypes are also associated with PUD.

  14. Helicobacter pylori virulence genes and host genetic polymorphisms as risk factors for peptic ulcer disease.

    PubMed

    Miftahussurur, Muhammad; Yamaoka, Yoshio

    2015-01-01

    Helicobacter pylori infection plays an important role in the pathogenesis of peptic ulcer disease (PUD). Several factors have been proposed as possible H. pylori virulence determinants; for example, bacterial adhesins and gastric inflammation factors are associated with an increased risk of PUD. However, differences in bacterial virulence factors alone cannot explain the opposite ends of the PUD disease spectrum, that is duodenal and gastric ulcers; presumably, both bacterial and host factors contribute to the differential response. Carriers of the high-producer alleles of the pro-inflammatory cytokines IL-1B, IL-6, IL-8, IL-10, and TNF-α who also carry low-producer allele of anti-inflammatory cytokines have severe gastric mucosal inflammation, whereas carriers of the alternative alleles have mild inflammation. Recent reports have suggested that the PSCA and CYP2C19 ultra-rapid metabolizer genotypes are also associated with PUD. PMID:26470920

  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.

  16. 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

  17. 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.

  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. 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

  20. 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

  1. 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

  2. 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

  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. 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

  5. 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

  6. 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

  7. 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.

  8. Tumour necrosis factor (TNF alpha) in leishmaniasis. I. TNF alpha mediates host protection against cutaneous leishmaniasis.

    PubMed Central

    Liew, F Y; Parkinson, C; Millott, S; Severn, A; Carrier, M

    1990-01-01

    Genetically resistant CBA mice developed significantly larger lesions to Leishmania major infection when they were injected with rabbit anti-tumour necrosis factor (TNF)-specific antibodies compared to control mice injected with normal rabbit immunoglobulin. BALB/c mice recovered from a previous infection following prophylactic sublethal irradiation also developed exacerbated lesions when treated with the anti-TNF antibody. Injection of TNF into the lesion of infected CBA mice significantly reduced the lesion development. Furthermore, TNF activates macrophages to kill Leishmania in vitro. These data demonstrate that TNF plays an important role in mediating host-protection against cutaneous leishmaniasis. PMID:2335376

  9. 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

  10. 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

    2015-01-01

    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

  11. 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

  12. 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

    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.

  13. 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

  14. Affinity proteomics reveals human host factors implicated in discrete stages of LINE-1 retrotransposition

    PubMed Central

    Taylor, Martin S.; LaCava, John; Mita, Paolo; Molloy, Kelly R.; Huang, Cheng Ran Lisa; Li, Donghui; Adney, Emily M.; Jiang, Hua; Burns, Kathleen H.; Chait, Brian T.; Rout, Michael P.; Boeke, Jef D.; Dai, Lixin

    2014-01-01

    LINE-1s are active human DNA parasites that are agents of genome dynamics in evolution and disease. These streamlined elements require host factors to complete their lifecycles, whereas hosts have developed mechanisms to combat retrotransposition’s mutagenic effects. As such, endogenous L1 expression levels are extremely low, creating a roadblock for detailed interactomic analyses. Here we describe a system to express and purify highly active L1 RNP complexes from human suspension cell culture and characterize the co-purified proteome, identifying 37 high-confidence candidate interactors. These datasets include known interactors PABPC1 and MOV10 and, with in-cell imaging studies, suggest existence of at least three types of compositionally and functionally distinct L1 RNPs. Among the novel findings, UPF1, a key nonsense-mediated decay factor, and PCNA, the polymerase-delta-associated sliding DNA clamp, were identified and validated. PCNA interacts with ORF2p via a PIP box motif; mechanistic studies suggest this occurs during or immediately after target-primed reverse transcription. PMID:24267889

  15. 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

  16. 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

  17. 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

  18. 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.

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

    PubMed Central

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

    2014-01-01

    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

  20. 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

  1. Host factors and genetic susceptibility to infections due to intracellular bacteria and fastidious organisms.

    PubMed

    Asner, S A; Morré, S A; Bochud, P-Y; Greub, G

    2014-12-01

    While genetic polymorphisms play a paramount role in tuberculosis (TB), less is known about their contribution to the severity of diseases caused by other intracellular bacteria and fastidious microorganisms. We searched electronic databases for observational studies reporting on host factors and genetic predisposition to infections caused by intracellular fastidious bacteria published up to 30 May 2014. The contribution of genetic polymorphisms was documented for TB. This includes genetic defects in the mononuclear phagocyte/T helper cell type 1 (Th1) pathway contributing to disseminated TB disease in children and genome-wide linkage analysis (GWAS) in reactivated pulmonary TB in adults. Similarly, experimental studies supported the role of host genetic factors in the clinical presentation of illnesses resulting from other fastidious intracellular bacteria. These include IL-6 -174G/C or low mannose-binding (MBL) polymorphisms, which are incriminated in chronic pulmonary conditions triggered by C. pneumoniae, type 2-like cytokine secretion polymorphisms, which are correlated with various clinical patterns of M. pneumoniae infections, and genetic variation in the NOD2 gene, which is an indicator of tubal pathology resulting from Chamydia trachomatis infections. Monocyte/macrophage migration and T lymphocyte recruitment defects are corroborated to ineffective granuloma formation observed among patients with chronic Q fever. Similar genetic polymorphisms have also been suggested for infections caused by T. whipplei although not confirmed yet. In conclusion, this review supports the paramount role of genetic factors in clinical presentations and severity of infections caused by intracellular fastidious bacteria. Genetic predisposition should be further explored through such as exome sequencing.

  2. 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

  3. Insulin-like growth factor I preserves host lean tissue mass in cancer cachexia.

    PubMed

    Ng, E H; Rock, C S; Lazarus, D D; Stiaino-Coico, L; Moldawer, L L; Lowry, S F

    1992-03-01

    Insulin-like growth factor I (IGF-I) has been implicated in the regulation and maintenance of skeletal muscle protein balance and thus may be of potential benefit in attenuating the cancer-cachectic process. To examine this hypothesis, 47 sham or tumor-implanted Fischer 344 rats were randomized to receive either continuous subcutaneous IGF-I (220 or 400 micrograms/day) or saline as control. In the tumor-bearing (TB) population, IGF-I-treated groups showed a dose-dependent increase in host weight gain (P less than 0.05), final carcass weight (P less than 0.05), and gastrocnemius muscle weights (P less than 0.05) and protein contents (0.50 +/- 0.02, 0.40 +/- 0.01, and 0.52 +/- 0.03 g/100 g host wt, for non-TB saline, TB saline, and TB 400 mg IGF-I groups, respectively; P less than 0.01, IGF-I vs. saline). Similar increases in muscle RNA and DNA contents (P less than 0.01) were induced by IGF-I treatment (P less than 0.05). IGF-I treatment in this rat sarcoma model significantly reduced the proportion of aneuploid cells in the tumor (aneuploid-to-diploid ratio: TB saline 1.1 +/- 0.2 vs. TB IGF-I 0.5 +/- 0.1; P less than 0.05). IGF-I treatment attenuated host muscle protein and lean tissue depletion without stimulation of tumor growth. The tumor aneuploid population was reduced in response to IGF-I treatment. Thus IGF-I may be a potential therapeutic agent in cancer-induced cachexia.

  4. Modulation of Bacterial Pathogenesis by Oppressive Aging Factors: Insights into Host-Pneumococcal Interaction Strategies

    PubMed Central

    Shivshankar, Pooja

    2012-01-01

    Streptococcus pneumonia, (Spn, the pneumococcus), is the leading cause of community-acquired pneumonia (CAP) and is responsible for 15–40% deaths in the elderly worldwide. A primed inflammatory status is a significant risk factor for the increased severity of infectious diseases among the elderly (≥65 years of age). Studies have shown that expression of host receptors that the pneumococci bind to invade the tissues are increased thereby increasing the susceptibility to pneumococcal challenge in aged mice. Cellular senescence, an age-related phenomenon that leads to cell cycle arrest may also contribute to increased inflammation in aged mice. Evidence of cellular senescence in aged lungs of humans and mice adds credits to the concept of inflammaging and enhanced bacterial ligands expression during aging. Furthermore, cell senescence has been shown to occur in age-associated lung pathologies such as idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD) that may predispose the elderly to pathogenic assaults, including S. pneumoniae. This review highlights the aspects of: chronic inflammation in the aged population; contribution of cellular senescence to age-associated inflammation and their impact on host receptor expression; and, increased susceptibility of fibrosis and emphysematous lesions-bearing lungs to microbial infections. PMID:24049644

  5. Adhesins and host serum factors drive Yop translocation by yersinia into professional phagocytes during animal infection.

    PubMed

    Maldonado-Arocho, Francisco J; Green, Carlos; Fisher, Michael L; Paczosa, Michelle K; Mecsas, Joan

    2013-01-01

    Yersinia delivers Yops into numerous types of cultured cells, but predominantly into professional phagocytes and B cells during animal infection. The basis for this cellular tropism during animal infection is not understood. This work demonstrates that efficient and specific Yop translocation into phagocytes by Yersinia pseudotuberculosis (Yptb) is a multi-factorial process requiring several adhesins and host complement. When WT Yptb or a multiple adhesin mutant strain, ΔailΔinvΔyadA, colonized tissues to comparable levels, ΔailΔinvΔyadA translocated Yops into significantly fewer cells, demonstrating that these adhesins are critical for translocation into high numbers of cells. However, phagocytes were still selectively targeted for translocation, indicating that other bacterial and/or host factors contribute to this function. Complement depletion showed that complement-restricted infection by ΔailΔinvΔyadA but not WT, indicating that adhesins disarm complement in mice either by prevention of opsonophagocytosis or by suppressing production of pro-inflammatory cytokines. Furthermore, in the absence of the three adhesins and complement, the spectrum of cells targeted for translocation was significantly altered, indicating that Yersinia adhesins and complement direct Yop translocation into neutrophils during animal infection. In summary, these findings demonstrate that in infected tissues, Yersinia uses adhesins both to disarm complement-dependent killing and to efficiently translocate Yops into phagocytes.

  6. 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

  7. 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

  8. 34 CFR 377.22 - What additional factors does the Secretary consider in making grants?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... PROJECTS TO INCREASE CLIENT CHOICE PROGRAM How Does the Secretary Make an Award? § 377.22 What additional factors does the Secretary consider in making grants? In addition to the criteria in § 377.21, the... strategies to increase client choice, in order to ensure that a variety of approaches are demonstrated...

  9. 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

  10. 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

  11. 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

  12. The Gut Microbiota Composition in Dichorionic Triplet Sets Suggests a Role for Host Genetic Factors

    PubMed Central

    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

  13. Studies on animal schistosomes in Peninsular Malaysia: record of naturally infected animals and additional hosts of Schistosoma spindale.

    PubMed

    Inder Singh, K; Krishnasamy, M; Ambu, S; Rasul, R; Chong, N L

    1997-06-01

    Surveillance studies on cercarial dermatitis were carried out in paddy growing areas in Peninsular Malaysia. It was observed that dermatitis in paddy planters occurred in paddy fields which were cultivated using animals such as bafflos or fields where domestic animals were allowed to graze during the off planting season as these animals harbored the parasite. The causative agent of cercarial dermatitis was Schistosoma spindale. A total of 215 small mammals trapped from Alor Setar and 126 trapped from Labu were examined for the schistosome. In Alor Setar Bandicota indica, Rattus argentiventer and Rattus rattus diardii were the only wild mammals found to be infected with the parasite, while in the Labu areas only Rattus tiomanicus jalorensis was positive for the schistosome. The occurrence of S. spindale in R. argentiventer and R.r. diardii in Alor Setar and in R.t. jalorensis in Labu constitute new host and geographic distribution records of the schistosome.

  14. 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

  15. Orchestrating the Selection and Packaging of Genomic RNA by Retroviruses: An Ensemble of Viral and Host Factors

    PubMed Central

    Kaddis Maldonado, Rebecca J.; Parent, Leslie J.

    2016-01-01

    Infectious retrovirus particles contain two copies of unspliced viral RNA that serve as the viral genome. Unspliced retroviral RNA is transcribed in the nucleus by the host RNA polymerase II and has three potential fates: (1) it can be spliced into subgenomic messenger RNAs (mRNAs) for the translation of viral proteins; or it can remain unspliced to serve as either (2) the mRNA for the translation of Gag and Gag–Pol; or (3) the genomic RNA (gRNA) that is packaged into virions. The Gag structural protein recognizes and binds the unspliced viral RNA to select it as a genome, which is selected in preference to spliced viral RNAs and cellular RNAs. In this review, we summarize the current state of understanding about how retroviral packaging is orchestrated within the cell and explore potential new mechanisms based on recent discoveries in the field. We discuss the cis-acting elements in the unspliced viral RNA and the properties of the Gag protein that are required for their interaction. In addition, we discuss the role of host factors in influencing the fate of the newly transcribed viral RNA, current models for how retroviruses distinguish unspliced viral mRNA from viral genomic RNA, and the possible subcellular sites of genomic RNA dimerization and selection by Gag. Although this review centers primarily on the wealth of data available for the alpharetrovirus Rous sarcoma virus, in which a discrete RNA packaging sequence has been identified, we have also summarized the cis- and trans-acting factors as well as the mechanisms governing gRNA packaging of other retroviruses for comparison. PMID:27657110

  16. 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

  17. 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

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

    PubMed

    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

  19. 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

  20. Caenorhabditis elegans-based screen identifies Salmonella virulence factors required for conserved host-pathogen interactions.

    PubMed

    Tenor, Jennifer L; McCormick, Beth A; Ausubel, Frederick M; Aballay, Alejandro

    2004-06-01

    A Caenorhabditis elegans-Salmonella enterica host-pathogen model was used to identify both novel and previously known S. enterica virulence factors (HilA, HilD, InvH, SptP, RhuM, Spi4-F, PipA, VsdA, RepC, Sb25, RfaL, GmhA, LeuO, CstA, and RecC), including several related to the type III secretion system (TTSS) encoded in Salmonella pathogenicity island 1 (SPI-1). Mutants corresponding to presumptive novel virulence-related genes exhibited diminished ability to invade epithelial cells and/or to induce polymorphonuclear leukocyte migration in a tissue culture model of mammalian enteropathogenesis. When expressed in C. elegans intestinal cells, the S. enterica TTSS-exported effector protein SptP inhibited a conserved p38 MAPK signaling pathway and suppressed the diminished pathogenicity phenotype of an S. enterica sptP mutant. These results show that C. elegans is an attractive model to study the interaction between Salmonella effector proteins and components of the innate immune response, in part because there is a remarkable overlap between Salmonella virulence factors required for human and nematode pathogenesis.

  1. 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

  2. Modulation of Innate Host Factors by Mycobacterium avium Complex in Human Macrophages Includes Interleukin 17

    PubMed Central

    Vázquez, Nancy; Rekka, Sofia; Gliozzi, Maria; Feng, Carl G.; Amarnath, Shoba; Orenstein, Jan M.; Wahl, Sharon M.

    2012-01-01

    Background. Although opportunistic infections due to Mycobacterium avium complex (MAC) have been less common since the introduction of highly active antiretroviral therapy, globally, human immunodeficiency virus-1 (HIV-1)–positive patients remain predisposed to these infections. Absence of a properly functioning acquired immune response allows MAC persistence within macrophages localized in lymph nodes coinfected with HIV and MAC. Although a deficiency in interferon γ appears to play a part in the ability of MAC to deflect the macrophage-associated antimicrobial attack, questions about this process remain. Our study examines the ability of MAC to regulate interleukin 17 (IL-17), a proinflammatory cytokine involved in host cell recruitment. Methods. Coinfected lymph nodes were examined for IL-17 by immunohistochemical analysis. In vitro, macrophages exposed to mycobacteria were evaluated for transcription activities, proteins, and signaling pathways responsible for IL-17 expression. Infected macrophages were also analyzed for expression of interleukin 21 (IL-21) and negative regulators of immune responses. Results. Infection of macrophages triggered synthesis of IL-17, correlating with IL-17 expression by macrophages in coinfected lymph nodes. Infected macrophages exposed to exogenous IL-17 expressed CXCL10, which favors recruitment of new macrophages as targets for infection. Blockade of nuclear factor κ-light-chain-enhancer of activated B cells and mitogen-activated protein kinase pathways suppressed mycobacteria-induced IL-17 expression. MAC triggered expression of IL-21, IRF4, and STAT3 genes related to IL-17 regulation, as well as expression of the negative immunoregulators CD274(PD-L1) and suppressors of cytokine signaling. Conclusions. MAC-infected macrophages can provide an alternative source for IL-17 that favors accumulation of new targets for perpetuating bacterial and viral infection while suppressing host antimicrobial immune responses. PMID

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

    PubMed

    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

    2015-10-01

    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.

  4. 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

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

    PubMed

    Sun, Xingmin; Hirota, Simon A

    2015-02-01

    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 C. 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.

  6. Factors Influencing Host Plant Choice and Larval Performance in Bactericera cockerelli

    PubMed Central

    Prager, Sean M.; Esquivel, Isaac; Trumble, John T.

    2014-01-01

    Among the many topics of interest to ecologists studying associations between phytophagous insects and their host plants are the influence of natal host plant on future oviposition decisions and the mechanisms of generalist versus specialist host selection behavior. In this study, we examined the oviposition preferences, behavior and larval development of the tomato/potato psyllid, Bactericera cockerelli. By rearing psyllids with two distinct geographically-linked haplotypes on different host plants, we were able to examine the role of natal host plant and potential local adaptation on host plant usage. Choice bioassays among three host species demonstrated that psyllids from California had clear preferences that were influenced by natal plant. We further found that patterns in choice bioassays corresponded to observed feeding and movement responses. No-choice bioassays demonstrated that there is little to no association between development and host-plant choice for oviposition, while also indicating that host choice varies between haplotypes. These findings support the concept that mothers do not always choose oviposition sites optimally and also add support for the controversial Hopkins' host selection principle. PMID:24710468

  7. 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

  8. Interaction of MYC with Host Cell Factor-1 is meditated by the evolutionarily-conserved Myc box IV motif

    PubMed Central

    Thomas, Lance R.; Foshage, Audra M.; Weissmiller, April M.; Popay, Tessa M.; Grieb, Brian C.; Qualls, Susan J.; Ng, Victoria; Carboneau, Bethany; Lorey, Shelly; Eischen, Christine M.; Tansey, William P.

    2015-01-01

    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 cofactors 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 Myc box motifs (MbI, MbII, MbIIIa, and MbIIIb) have had a molecular function assigned to them, but the precise role of the remaining Myc box, 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 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

  9. 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

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

    PubMed

    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

    2010-11-01

    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

  11. The contribution of tumor and host tissue factor expression to oncogene-driven gliomagenesis.

    PubMed

    Magnus, Nathalie; Meehan, Brian; Garnier, Delphine; Hashemi, Maryam; Montermini, Laura; Lee, Tae Hoon; Milsom, Chloe; Pawlinski, Rafal; Ohlfest, John; Anderson, Mark; Mackman, Nigel; Rak, Janusz

    2014-11-14

    Glioblastoma multiforme (GBM) is an aggressive form of glial brain tumors, associated with angiogenesis, thrombosis, and upregulation of tissue factor (TF), the key cellular trigger of coagulation and signaling. Since TF is upregulated by oncogenic mutations occurring in different subsets of human brain tumors we investigated whether TF contributes to tumourigenesis driven by oncogenic activation of EGFR (EGFRvIII) and RAS pathways in the brain. Here we show that TF expression correlates with poor prognosis in glioma, but not in GBM. In situ, the TF protein expression is heterogeneously expressed in adult and pediatric gliomas. GBM cells harboring EGFRvIII (U373vIII) grow aggressively as xenografts in SCID mice and their progression is delayed by administration of monoclonal antibodies blocking coagulant (CNTO 859) and signaling (10H10) effects of TF in vivo. Mice in which TF gene is disrupted in the neuroectodermal lineage exhibit delayed progression of spontaneous brain tumors driven by oncogenic N-ras and SV40 large T antigen (SV40LT) expressed under the control of sleeping beauty transposase. Reduced host TF levels in low-TF/SCID hypomorphic mice mitigated growth of glioma subcutaneously but not in the brain. Thus, we suggest that tumor-associated TF may serve as therapeutic target in the context of oncogene-driven disease progression in a subset of glioma.

  12. 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

  13. Temporal SILAC-based quantitative proteomics identifies host factors involved in chikungunya virus replication.

    PubMed

    Treffers, Emmely E; Tas, Ali; Scholte, Florine E M; Van, Myrthe N; Heemskerk, Matthias T; de Ru, Arnoud H; Snijder, Eric J; van Hemert, Martijn J; van Veelen, Peter A

    2015-07-01

    Chikungunya virus (CHIKV) is an arthropod-borne reemerging human pathogen that generally causes a severe persisting arthritis. Since 2005, the virus has infected millions of people during outbreaks in Africa, Indian Ocean Islands, Asia, and South/Central America. Many steps of the replication and expression of CHIKV's 12-kb RNA genome are highly dependent on cellular factors, which thus constitute potential therapeutic targets. SILAC and LC-MS/MS were used to define the temporal dynamics of the cellular response to infection. Using samples harvested at 8, 10, and 12 h postinfection, over 4700 proteins were identified and per time point 2800-3500 proteins could be quantified in both biological replicates. At 8, 10, and 12 h postinfection, 13, 38, and 106 proteins, respectively, were differentially expressed. The majority of these proteins showed decreased abundance. Most subunits of the RNA polymerase II complex were progressively degraded, which likely contributes to the transcriptional host shut-off observed during CHIKV infection. Overexpression of four proteins that were significantly downregulated (Rho family GTPase 3 (Rnd3), DEAD box helicase 56 (DDX56), polo-like kinase 1 (Plk1), and ubiquitin-conjugating enzyme E2C (UbcH10) reduced susceptibility of cells to CHIKV infection, suggesting that infection-induced downregulation of these proteins is beneficial for CHIKV replication. All MS data have been deposited in the ProteomeXchange with identifier PXD001330 (http://proteomecentral.proteomexchange.org/dataset/PXD001330).

  14. 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

  15. 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

  16. 34 CFR 648.32 - 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? 648.32 Section 648.32 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION GRADUATE ASSISTANCE IN AREAS OF NATIONAL...

  17. 34 CFR 491.22 - 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? 491.22 Section 491.22 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION ADULT EDUCATION FOR THE...

  18. 34 CFR 491.22 - 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? 491.22 Section 491.22 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION ADULT EDUCATION FOR THE...

  19. 34 CFR 491.22 - 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? 491.22 Section 491.22 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION ADULT EDUCATION FOR THE...

  20. 34 CFR 491.22 - 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? 491.22 Section 491.22 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION ADULT EDUCATION FOR THE...

  1. 34 CFR 491.22 - 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? 491.22 Section 491.22 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION ADULT EDUCATION FOR THE...

  2. 34 CFR 636.22 - 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? 636.22 Section 636.22 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION URBAN COMMUNITY SERVICE PROGRAM How Does...

  3. 34 CFR 636.22 - What additional factors 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 factors does the Secretary consider? 636.22 Section 636.22 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION URBAN COMMUNITY SERVICE PROGRAM How Does...

  4. 34 CFR 636.22 - What additional factors 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 factors does the Secretary consider? 636.22 Section 636.22 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION URBAN COMMUNITY SERVICE PROGRAM How Does...

  5. 34 CFR 636.22 - What additional factors 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 factors does the Secretary consider? 636.22 Section 636.22 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION URBAN COMMUNITY SERVICE PROGRAM How Does...

  6. 34 CFR 636.22 - What additional factors 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 factors does the Secretary consider? 636.22 Section 636.22 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION URBAN COMMUNITY SERVICE PROGRAM How Does...

  7. 21 CFR 1311.115 - Additional requirements for two-factor authentication.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 9 2013-04-01 2013-04-01 false Additional requirements for two-factor authentication. 1311.115 Section 1311.115 Food and Drugs DRUG ENFORCEMENT ADMINISTRATION, DEPARTMENT OF JUSTICE... criteria of FIPS 140-2 Security Level 1, as incorporated by reference in § 1311.08, for...

  8. 21 CFR 1311.115 - Additional requirements for two-factor authentication.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 9 2012-04-01 2012-04-01 false Additional requirements for two-factor authentication. 1311.115 Section 1311.115 Food and Drugs DRUG ENFORCEMENT ADMINISTRATION, DEPARTMENT OF JUSTICE... criteria of FIPS 140-2 Security Level 1, as incorporated by reference in § 1311.08, for...

  9. 34 CFR 425.22 - 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? 425.22 Section 425.22 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION DEMONSTRATION PROJECTS FOR...

  10. 34 CFR 648.32 - What additional factors does the Secretary consider?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... private institutions of higher education. (Authority: 20 U.S.C. 1135-1135c) ... 34 Education 3 2011-07-01 2011-07-01 false What additional factors does the Secretary consider? 648.32 Section 648.32 Education Regulations of the Offices of the Department of Education...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  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. Geographical, genetic and functional diversity of antiretroviral host factor TRIMCyp in cynomolgus macaque (Macaca fascicularis).

    PubMed

    Saito, Akatsuki; Kono, Ken; Nomaguchi, Masako; Yasutomi, Yasuhiro; Adachi, Akio; Shioda, Tatsuo; Akari, Hirofumi; Nakayama, Emi E

    2012-03-01

    The antiretroviral factor tripartite motif protein 5 (TRIM5) gene-derived isoform (TRIMCyp) has been found in at least three species of Old World monkey: rhesus (Macaca mulatta), pig-tailed (Macaca nemestrina) and cynomolgus (Macaca fascicularis) macaques. Although the frequency of TRIMCyp has been well studied in rhesus and pig-tailed macaques, the frequency and prevalence of TRIMCyp in cynomolgus macaques remain to be definitively elucidated. Here, the geographical and genetic diversity of TRIM5α/TRIMCyp in cynomolgus macaques was studied in comparison with their anti-lentiviral activity. It was found that the frequency of TRIMCyp in a population in the Philippines was significantly higher than those in Indonesian and Malaysian populations. Major and minor haplotypes of cynomolgus macaque TRIMCyp with single nucleotide polymorphisms in the cyclophilin A domain were also found. The functional significance of the polymorphism in TRIMCyp was examined, and it was demonstrated that the major haplotype of TRIMCyp suppressed human immunodeficiency virus type 1 (HIV-1) but not HIV-2, whilst the minor haplotype of TRIMCyp suppressed HIV-2 but not HIV-1. The major haplotype of TRIMCyp did not restrict a monkey-tropic HIV-1 clone, NL-DT5R, which contains a capsid with the simian immunodeficiency virus-derived loop between α-helices 4 and 5 and the entire vif gene. These results indicate that polymorphisms of TRIMCyp affect its anti-lentiviral activity. Overall, the results of this study will help our understanding of the genetic background of cynomolgus macaque TRIMCyp, as well as the host factors composing species barriers of primate lentiviruses.

  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. 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

  19. 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.

  20. Isolation of an additional member of the fibroblast growth factor receptor family, FGFR-3.

    PubMed Central

    Keegan, K; Johnson, D E; Williams, L T; Hayman, M J

    1991-01-01

    The fibroblast growth factors are a family of polypeptide growth factors involved in a variety of activities including mitogenesis, angiogenesis, and wound healing. Fibroblast growth factor receptors (FGFRs) have previously been identified in chicken, mouse, and human and have been shown to contain an extracellular domain with either two or three immunoglobulin-like domains, a transmembrane domain, and a cytoplasmic tyrosine kinase domain. We have isolated a human cDNA for another tyrosine kinase receptor that is highly homologous to the previously described FGFR. Expression of this receptor cDNA in COS cells directs the expression of a 125-kDa glycoprotein. We demonstrate that this cDNA encodes a biologically active receptor by showing that human acidic and basic fibroblast growth factors activate this receptor as measured by 45Ca2+ efflux assays. These data establish the existence of an additional member of the FGFR family that we have named FGFR-3. Images PMID:1847508

  1. 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.

  2. 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

  3. Genome-wide screening using RNAi (RNA interference) to study host factors in viral replication and pathogenesis

    PubMed Central

    Houzet, Laurent; Jeang, Kuan-Teh

    2012-01-01

    With the recent development of siRNA and shRNA expression libraries, RNAi technology has been extensively employed to identify genes involved in diverse cellular processes, such as signal transduction, cell cycle, cancer biology and host-pathogen interactions. In the field of viral infection, this approach has already identified hundreds of new genes not previously known to be important for various virus lifecycles. In this brief review, we focus on recent studies performed using genome-wide RNAi-based screens in mammalian cells for the identification of essential host factors for viral infection and pathogenesis. PMID:21727185

  4. 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

  5. Positive regulation of Shigella flexneri virulence genes by integration host factor.

    PubMed Central

    Porter, M E; Dorman, C J

    1997-01-01

    In Shigella flexneri, expression of the plasmid-encoded virulence genes is regulated via a complex cascade involving DNA topology, specific transactivators, and the nucleoid-associated protein H-NS, which represses transcription under inappropriate environmental conditions. We have investigated the involvement of a second nucleoid-associated protein, integration host factor (IHF), in virulence gene expression. We found that transcription of the invasion-specific genes is repressed in a strain harboring an ihfA mutation, particularly on entry into the stationary phase. Expression of the virB gene, whose product is required for the activation of these structural genes, is also enhanced by IHF in the stationary phase. In contrast, the virF gene, which encodes an activator of virB, is stimulated by IHF in both the logarithmic and early stationary phases of growth, as is another virF-regulated gene, icsA. We have identified regions of the virF, virB, and icsA promoters which form IHF-dependent protein-DNA complexes in vitro and have located sequences within these regions with similarity to the consensus IHF binding site. Moreover, results from experiments in which the virF or virB gene was expressed constitutively confirm that IHF has a direct input at the level of both virF and virB transcription. Finally, we provide evidence that at the latter promoter, the primary role of IHF may be to overcome repression by the H-NS protein. To our knowledge, this is the first report of a role for IHF in controlling gene expression in S. flexneri. PMID:9352898

  6. 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

  7. Antibodies directed against Integration Host Factor Mediate Biofilm Clearance from Nasopore®

    PubMed Central

    Brandstetter, Kathleyn A.; Jurcisek, Joseph A.; Goodman, Steven D.; Bakaletz, Lauren O.; Das, Subinoy

    2014-01-01

    Objectives Intranasal resorbable packing, such as Nasopore®, is commonly used during sinus surgery despite a paucity of evidence that demonstrates clinical benefit. We theorized that Nasopore supports bacterial growth and biofilm formation. The DNABII family of bacterial nucleic acid binding proteins stabilizes the extracellular polymeric substance of the biofilm, thus protecting bacteria from host defenses and traditional antibiotics. We tested the hypothesis that use of anti-IHF antibodies in conjunction with antibiotics would enhance biofilm eradication from Nasopore. Study Design In vitro experiments. Methods Non-typeable Haemophilus influenzae (NTHI) biofilms were grown on Nasopore. Following 24-hour incubation, biofilms were incubated for an additional 16 hours with either: medium alone, naïve rabbit serum, rabbit anti-IHF serum, amoxicillin/clavulanate or anti-IHF serum + amoxicillin/clavulanate. COMSTAT analysis was performed on images of biofilms obtained via confocal microscopy. Results NTHI readily formed a biofilm on Nasopore. Treatment with amoxicillin/clavulanate alone mediated an increase in biomass by 92% to 6.63 μ2/μ3 compared to incubation in sterile medium alone (3.46 μ2/μ3). Treatment with anti-IHF alone reduced the biomass by 77% to 1.29 μ2/μ3 compared to incubation with naïve rabbit serum (5.53 μ2/μ3). Anti-IHF + amoxicillin/clavulanate reduced biomass by 88% to 0.66 μ2/μ3 (p<0.02) compared to incubation with naïve rabbit serum. Conclusion Antibiotics alone were ineffective in eradicating NTHI biofilms that had formed on Nasopore in vitro. Anti-IHF antibodies plus amoxicillin/clavulanate therapy synergistically reduced biofilm biomass by 88%. These data support clinical studies for the use of anti-IHF combined with antibiotics to reduce biofilm formation on intranasal packing. PMID:23670606

  8. Ecological and genetic factors influencing the transition between host-use strategies in sympatric Heliconius butterflies.

    PubMed

    Merrill, R M; Naisbit, R E; Mallet, J; Jiggins, C D

    2013-09-01

    Shifts in host-plant use by phytophagous insects have played a central role in their diversification. Evolving host-use strategies will reflect a trade-off between selection pressures. The ecological niche of herbivorous insects is partitioned along several dimensions, and if populations remain in contact, recombination will break down associations between relevant loci. As such, genetic architecture can profoundly affect the coordinated divergence of traits and subsequently the ability to exploit novel habitats. The closely related species Heliconius cydno and H. melpomene differ in mimetic colour pattern, habitat and host-plant use. We investigate the selection pressures and genetic basis underlying host-use differences in these two species. Host-plant surveys reveal that H. melpomene specializes on a single species of Passiflora. This is also true for the majority of other Heliconius species in secondary growth forest at our study site, as expected under a model of interspecific competition. In contrast, H. cydno, which uses closed-forest habitats where both Heliconius and Passiflora are less common, appears not to be restricted by competition and uses a broad selection of the available Passiflora. However, other selection pressures are likely involved, and field experiments reveal that early larval survival of both butterfly species is highest on Passiflora menispermifolia, but most markedly so for H. melpomene, the specialist on that host. Finally, we demonstrate an association between host-plant acceptance and colour pattern amongst interspecific hybrids, suggesting that major loci underlying these important ecological traits are physically linked in the genome. Together, our results reveal ecological and genetic associations between shifts in habitat, host use and mimetic colour pattern that have likely facilitated both speciation and coexistence.

  9. A paradigm for endosymbiotic life: cell differentiation of Rhizobium bacteria provoked by host plant factors.

    PubMed

    Kondorosi, Eva; Mergaert, Peter; Kereszt, Attila

    2013-01-01

    Symbiosis between Rhizobium bacteria and legumes leads to the formation of the root nodule. The endosymbiotic bacteria reside in polyploid host cells as membrane-surrounded vesicles where they reduce atmospheric nitrogen to support plant growth by supplying ammonia in exchange for carbon sources and energy. The morphology and physiology of endosymbionts, despite their common function, are highly divergent in different hosts. In galegoid plants, the endosymbionts are terminally differentiated, uncultivable polyploid cells, with remarkably elongated and even branched Y-shaped cells. Bacteroid differentiation is controlled by host peptides, many of which have antibacterial activity and require the bacterial function of BacA. Although the precise and combined action of several hundred host peptides and BacA has yet to be discovered, similarities, especially to certain insect-bacterium symbioses involving likewise host peptides for manipulation of endosymbionts, suggest convergent evolution. Rhizobium-legume symbiosis provides a rich source of information for understanding host-controlled endosymbiotic life in eukaryotic cells.

  10. Genetic Factors and Host Traits Predict Spore Morphology for a Butterfly Pathogen

    PubMed Central

    Sander, Sarah E.; Altizer, Sonia; de Roode, Jacobus C.; Davis, Andrew K.

    2013-01-01

    Monarch butterflies (Danaus plexippus) throughout the world are commonly infected by the specialist pathogen Ophryocystis elektroscirrha (OE). This protozoan is transmitted when larvae ingest infectious stages (spores) scattered onto host plant leaves by infected adults. Parasites replicate internally during larval and pupal stages, and adult monarchs emerge covered with millions of dormant spores on the outsides of their bodies. Across multiple monarch populations, OE varies in prevalence and virulence. Here, we examined geographic and genetic variation in OE spore morphology using clonal parasite lineages derived from each of four host populations (eastern and western North America, South Florida and Hawaii). Spores were harvested from experimentally inoculated, captive-reared adult monarchs. Using light microscopy and digital image analysis, we measured the size, shape and color of 30 replicate spores per host. Analyses examined predictors of spore morphology, including parasite source population and clone, parasite load, and the following host traits: family line, sex, wing area, and wing color (orange and black pigmentation). Results showed significant differences in spore size and shape among parasite clones, suggesting genetic determinants of morphological variation. Spore size also increased with monarch wing size, and monarchs with larger and darker orange wings tended to have darker colored spores, consistent with the idea that parasite development depends on variation in host quality and resources. We found no evidence for effects of source population on variation in spore morphology. Collectively, these results provide support for heritable variation in spore morphology and a role for host traits in affecting parasite development. PMID:26462429

  11. 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

    2016-09-01

    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.

  12. Expression of the transposase gene tnpA of Tn4652 is positively affected by integration host factor.

    PubMed

    Hõrak, R; Kivisaar, M

    1998-06-01

    Tn4652 is a derivative of the toluene degradation transposon Tn4651 that belongs to the Tn3 family of transposons (M. Tsuda and T. Iino, Mol. Gen. Genet. 210:270-276, 1987). We have sequenced the transposase gene tnpA of transposon Tn4652 and mapped its promoter to the right end of the element. The deduced amino acid sequence of tnpA revealed 96.2% identity with the putative transposase of Tn5041. Homology with other Tn3 family transposases was only moderate (about 20 to 24% identity), suggesting that Tn4652 and Tn5041 are distantly related members of the Tn3 family. Functional analysis of the tnpA promoter revealed that it is active in Pseudomonas putida but silent in Escherichia coli, indicating that some P. putida-specific factor is required for the transcription from this promoter. Additionally, tnpA promoter activity was shown to be modulated by integration host factor (IHF). The presence of an IHF-binding site upstream of the tnpA promoter enhanced the promoter activity. The positive role of IHF was also confirmed by the finding that the enhancing effect of IHF was not detected in the P. putida ihfA-deficient strain A8759. Moreover, the Tn4652 terminal sequences had a negative effect on transcription from the tnpA promoter in the ihfA-defective strain. This finding suggests that IHF not only enhances transcription from the tnpA promoter but also alleviates the negative effect of terminal sequences of Tn4652 on the promoter activity. Also, an in vitro binding assay demonstrated that both ends of Tn4652 bind IHF from a cell lysate of E. coli. PMID:9603867

  13. 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

  14. 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

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

    PubMed

    Datta De, Dipanjana; Roychoudhury, Susanta

    2015-03-14

    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.

  16. Tumor-host interactions as prognostic factors in the histologic assessment of carcinomas.

    PubMed

    Crissman, J D

    1986-01-01

    Many of these observations appear to define a reasonable hypothesis. High-grade or poorly differentiated malignant neoplasms have a shorter tumor-doubling time, are less cohesive, often with irregular borders, and tend to invade by small aggregates and individual tumor cells. The observation of the pattern of invasion provides considerable information on the aggressiveness of the neoplasm. The pattern of invasion appears to correlate with tumor cell cohesiveness, motility, loss of contact inhibition, excretion of enzymes, and other factors associated with aggressiveness in experimental models. It is clear that the pattern of tumor-host interaction indirectly reflects many of these parameters and provides major clues to the biologic potential of human carcinomas. These observations should be used to supplement the histologic and cytologic features commonly used to derive a tumor grade. Aggressive tumors are usually larger and are associated with a greater blood supply. Vascular invasion is more common in this situation and large veins may be invaded by tumor by intravascular growth. Penetration of small lymphatic and blood vessels is associated with a poor prognosis and involvement of large veins with intravascular extensions of tumor have the potential of releasing tumor cell aggregates or emboli into the venous circulation. These large tumor cell aggregates have been demonstrated to be associated with a higher efficiency of metastasis formation and infer a poorer prognosis. Why have I bothered with all this detail about the occurrence of circulating tumor cells and their relation to the development of metastases? It must be stressed that many malignant cells are being released into the circulation of cancer patients and few, if any, ever successfully complete the complex sequence leading to a metastatic focus. This has been termed "metastatic inefficiency." Other investigators have referred to the unique cells that have mastered the intricate sequence of steps

  17. 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.

  18. 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

  19. IHF is the limiting host factor in transposition of Pseudomonas putida transposon Tn4652 in stationary phase.

    PubMed

    Ilves, Heili; Hõrak, Rita; Teras, Riho; Kivisaar, Maia

    2004-03-01

    Transpositional activity of mobile elements is not constant. Conditional regulation of host factors involved in transposition may severely change the activity of mobile elements. We have demonstrated previously that transposition of Tn4652 in Pseudomonas putida is a stationary phase-specific event, which requires functional sigma S (Ilves et al., 2001, J Bacteriol 183: 5445-5448). We hypothesized that integration host factor (IHF), the concentration of which is increased in starving P. putida, might contribute to the transposition of Tn4652 as well. Here, we demonstrate that transposition of Tn4652 in stationary phase P. putida is essentially limited by the amount of IHF. No transposition of Tn4652 occurs in a P. putida ihfA-defective strain. Moreover, overexpression of IHF results in significant enhancement of transposition compared with the wild-type strain. This indicates that the amount of IHF is a bottleneck in Tn4652 transposition. Gel mobility shift and DNase I footprinting studies revealed that IHF is necessary for the binding of transposase to both transposon ends. In vitro, transposase can bind to inverted repeats of transposon only after the binding of IHF. The results obtained in this study indicate that, besides sigma S, IHF is another host factor that is implicated in the elevation of transposition in stationary phase. PMID:15009901

  20. Radiation-induced mouse chimeras: a cellular analysis of the major lymphoid compartments, factors affecting lethal graft versus host disease and host-tumor interactions

    SciTech Connect

    Almaraz, R.

    1981-01-01

    The major lymphoid compartments of allogeneic bone marrow chimeras were evaluated for the extent of cell chimerism and distribution of Thy 1 and la bearing cells. These chimeras contained lymphoid cell primarily of donor origin. The bone marrow compartment was a mixture of host and donor origin cells. The distribution of Thy 1 and la bearing cells was similar as in normal mice. The effect of adult thymectomy alone or followed by whole-body irradiation and bone marrow reconstitution on the distribution of the Thy 1 positive cells was also investigated. Thymectomy with or without WBI and bone marrow reconstitution significantly lowered the number of Thy 1 bearing cells in the blood and spleen. The number of la bearing cells did not appear to be affected by thymectomy. The role of circulating lymphoid cells in the incidence of lethal graft versus host disease (GVHD) in radiation induced fully allogeneic mouse chimeras was studied. Mice reconstituted with allogeneic bone marrow from bled donors had a statistically lower incidence of GVHD than those reconstituted with bone marrow from unbled donors. Addition of mature peripheral lymphocytes from blood to the reconstituting bone marrow cells from bled donors reduplicated the high incidence of lethal GVHD. It was demonstrated that the bone marrow of mice not exsanguinated prior to harvesting of bone marrow contained significant numbers of peripheral contaminating cells in the harvested bone marrow. The role of suppressor cell elimination in resisting tumor growth was investigated using radiation induced mouse chimeras. Local effects of irradiation alone at the site of tumor inoculation could account for this lack of growth.

  1. 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

  2. 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

  3. Arginine methylation enhances the RNA chaperone activity of the West Nile virus host factor AUF1 p45.

    PubMed

    Friedrich, Susann; Schmidt, Tobias; Schierhorn, Angelika; Lilie, Hauke; Szczepankiewicz, Grit; Bergs, Sandra; Liebert, Uwe G; Golbik, Ralph P; Behrens, Sven-Erik

    2016-10-01

    A prerequisite for the intracellular replication process of the Flavivirus West Nile virus (WNV) is the cyclization of the viral RNA genome, which enables the viral replicase to initiate RNA synthesis. Our earlier studies indicated that the p45 isoform of the cellular AU-rich element binding protein 1 (AUF1) has an RNA chaperone activity, which supports RNA cyclization and viral RNA synthesis by destabilizing a stem structure at the WNV RNA's 3'-end. Here we show that in mammalian cells, AUF1 p45 is consistently modified by arginine methylation of its C terminus. By a combination of different experimental approaches, we can demonstrate that the methyltransferase PRMT1 is necessary and sufficient for AUF1 p45 methylation and that PRMT1 is required for efficient WNV replication. Interestingly, in comparison to the nonmethylated AUF1 p45, the methylated AUF1 p45(aDMA) exhibits a significantly increased affinity to the WNV RNA termini. Further data also revealed that the RNA chaperone activity of AUF1 p45(aDMA) is improved and the methylated protein stimulates viral RNA synthesis considerably more efficiently than the nonmethylated AUF1 p45. In addition to its destabilizing RNA chaperone activity, we identified an RNA annealing activity of AUF1 p45, which is not affected by methylation. Arginine methylation of AUF1 p45 thus represents a specific determinant of its RNA chaperone activity while functioning as a WNV host factor. Our data suggest that the methylation modifies the conformation of AUF1 p45 and in this way affects its RNA binding and restructuring activities.

  4. 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

    2016-07-29

    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.

  5. 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

  6. Tracking the dynamic interplay between bacterial and host factors during pathogen-induced vacuole rupture in real time.

    PubMed

    Ray, Katrina; Bobard, Alexandre; Danckaert, Anne; Paz-Haftel, Irit; Clair, Caroline; Ehsani, Soudeh; Tang, Christoph; Sansonetti, Philippe; Tran, Guy Van Nhieu; Enninga, Jost

    2010-04-01

    Escape into the host cell cytosol following invasion of mammalian cells is a common strategy used by invasive pathogens. This requires membrane rupture of the vesicular or vacuolar compartment formed around the bacteria after uptake into the host cell. The mechanism of pathogen-induced disassembly of the vacuolar membrane is poorly understood. We established a novel, robust and sensitive fluorescence microscopy method that tracks the precise time point of vacuole rupture upon uptake of Gram-negative bacteria. This revealed that the enteroinvasive pathogen Shigella flexneri escapes rapidly, in less than 10 min, from the vacuole. Our method demonstrated the recruitment of host factors, such as RhoA, to the bacterial entry site and their continued presence at the point of vacuole rupture. We found a novel host marker for ruptured vacuoles, galectin-3, which appears instantly in the proximity of bacteria after escape into the cytosol. Furthermore, we show that the Salmonella effector proteins, SifA and PipB2, stabilize the vacuole membrane inhibiting bacterial escape from the vacuole. Our novel approach to track vacuole rupture is ideally suited for high-content and high-throughput approaches to identify the molecular and cellular mechanisms of membrane rupture during invasion by pathogens such as viruses, bacteria and parasites.

  7. 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

  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. The late endosomal adaptor p14 is a macrophage host-defense factor against Salmonella infection.

    PubMed

    Taub, Nicole; Nairz, Manfred; Hilber, Diana; Hess, Michael W; Weiss, Günter; Huber, Lukas A

    2012-06-01

    The outcome of an infection depends on the balance between host resistance and bacterial virulence. Here, we show that the late endosomal adaptor p14 (also known as LAMTOR2) is one of the components for cellular host defense against the intracellular pathogen Salmonella enterica serovar Typhimurium. During Salmonella infection, the complex of p14 and MP1 is required for the accurately timed transport of Salmonella through the endolysosomal system. Loss of p14 opens a time window that allows Salmonella to populate a replication niche, in which early and late antimicrobial effector systems, comprising NADPH phagocytic oxidase and inducible nitric oxide synthase, respectively, are inappropriately activated. Thus, p14 supports the accurate transport of Salmonella through the endolysosomal system, thereby limiting bacterial replication in both, professional phagocytes and in non-phagocytic cells in vitro, and helps mice to successfully battle Salmonella infection in vivo.

  12. 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.

  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.

  14. Herpes simplex virus virion host shutoff protein requires a mammalian factor for efficient in vitro endoribonuclease activity.

    PubMed

    Lu, P; Jones, F E; Saffran, H A; Smiley, J R

    2001-02-01

    The virion host shutoff protein (vhs) of herpes simplex virus (HSV) triggers global shutoff of host protein synthesis and accelerated mRNA turnover during virus infection and induces endoribonucleolytic cleavage of exogenous RNA substrates when it is produced in a rabbit reticulocyte (RRL) in vitro translation system. Although vhs induces RNA turnover in the absence of other HSV gene products, it is not yet known whether cellular factors are required for its activity. As one approach to addressing this question, we expressed vhs in the budding yeast Saccharomyces cerevisiae. Expression of vhs inhibited colony formation, and the severity of this effect varied with the carbon source. The biological relevance of this effect was assessed by examining the activity of five mutant forms of vhs bearing previously characterized in-frame linker insertions. The results indicated a complete concordance between the growth inhibition phenotype in yeast and mammalian host cell shutoff. Despite these results, expression of vhs did not trigger global mRNA turnover in vivo, and cell extracts of yeast expressing vhs displayed little if any vhs-dependent endoribonuclease activity. However, activity was readily detected when such extracts were mixed with RRL. These data suggest that the vhs-dependent endoribonuclease requires one or more mammalian macromolecular factors for efficient activity.

  15. Coordinated destruction of cellular messages in translation complexes by the gammaherpesvirus host shutoff factor and the mammalian exonuclease Xrn1.

    PubMed

    Covarrubias, Sergio; Gaglia, Marta M; Kumar, G Renuka; Wong, Wesley; Jackson, Andrew O; Glaunsinger, Britt A

    2011-10-01

    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.

  16. 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.

  17. 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.

  18. [DISSEMINATED NONTUBERCULOUS MYCOBACTERIOSIS THAT IS POSITIVE FOR NEUTRALIZING ANTI-INTERFERON-GAMMA AUTOANTIBODIES: A NEW DISEASE CONCEPT BASED ON HOST FACTORS].

    PubMed

    Sakagami, Takuro

    2015-06-01

    Disseminated nontuberculous mycobacteriosis (NTM infection) is a disease that causes multiple organ lesions and occurs against an immunodeficiency background. Several host factors for this disease have been identified. Recently, neutralizing anti-interferon-γ autoantibodies (IFN-γ Ab) have been detected in some cases of disseminated NTM infection that had no previously known immunodeficiency, garnering attention as a new form of acquired immunodeficiency. We previously reported on methods for detecting IFN-γ Ab in clinical specimens as part of the diagnostic process that are being used to evaluate suspected cases at various institutions. Overseas reports of positive results were achieved by administration of the anti-CD20 antibody rituximab in addition to antibacterial chemotherapy in cases of intractable disseminated NTM infection that tested positive for IFN-γ Ab. This highlights the importance of diagnosis as well. Clinicians should consider the existence of this pathology. Although many host factors for NTM infection have yet to be identified, IFN-γ Ab positivity should be investigated further as a new disease concept, not only for its pathological dimensions but also from the standpoint of treatment strategies. In the future, more cases need to be examined and analyzed to obtain further epidemiological and pathological findings.

  19. Genome-wide analysis of host factors in nodavirus RNA replication.

    PubMed

    Hao, Linhui; Lindenbach, Brett; Wang, Xiaofeng; Dye, Billy; Kushner, David; He, Qiuling; Newton, Michael; Ahlquist, Paul

    2014-01-01

    Flock House virus (FHV), the best studied of the animal nodaviruses, has been used as a model for positive-strand RNA virus research. As one approach to identify host genes that affect FHV RNA replication, we performed a genome-wide analysis using a yeast single gene deletion library and a modified, reporter gene-expressing FHV derivative. A total of 4,491 yeast deletion mutants were tested for their ability to support FHV replication. Candidates for host genes modulating FHV replication were selected based on the initial genome-wide reporter gene assay and validated in repeated Northern blot assays for their ability to support wild type FHV RNA1 replication. Overall, 65 deletion strains were confirmed to show significant changes in the replication of both FHV genomic RNA1 and sub-genomic RNA3 with a false discovery rate of 5%. Among them, eight genes support FHV replication, since their deletion significantly reduced viral RNA accumulation, while 57 genes limit FHV replication, since their deletion increased FHV RNA accumulation. Of the gene products implicated in affecting FHV replication, three are localized to mitochondria, where FHV RNA replication occurs, 16 normally reside in the nucleus and may have indirect roles in FHV replication, and the remaining 46 are in the cytoplasm, with functions enriched in translation, RNA processing and trafficking. PMID:24752411

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

    PubMed

    González-Barrio, David; 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

    2015-09-01

    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.

  1. Virulence factor regulation and regulatory networks in Streptococcus pyogenes and their impact on pathogen-host interactions.

    PubMed

    Kreikemeyer, Bernd; McIver, Kevin S; Podbielski, Andreas

    2003-05-01

    Streptococcus pyogenes (group A streptococcus, GAS) is a very important human pathogen with remarkable adaptation capabilities. Survival within the harsh host surroundings requires sensing potential on the bacterial side, which leads in particular to coordinately regulated virulence factor expression. GAS 'stand-alone' response regulators (RRs) and two-component signal transduction systems (TCSs) link the signals from the host environment with adaptive responses of the bacterial cell. Numerous putative regulatory systems emerged from GAS genome sequences. Only three RRs [Mga, RofA-like protein (RALP) and Rgg/RopB] and three TCSs (CsrRS/CovRS, FasBCAX and Ihk/Irr) have been studied in some detail with respect to their growth-phase-dependent activity and their influence on GAS-host cell interaction. In particular, the Mga-, RALP- and Rgg/RopB-regulated pathways display interconnected activities that appear to influence GAS colonization, persistence and spreading mechanisms, in a growth-phase-related fashion. Here, we have summarized our current knowledge about these RRs and TCSs to highlight the questions that should be addressed in future research on GAS pathogenicity.

  2. Dual interaction of factor H with C3d and glycosaminoglycans in host-nonhost discrimination by complement.

    PubMed

    Kajander, Tommi; Lehtinen, Markus J; Hyvärinen, Satu; Bhattacharjee, Arnab; Leung, Elisa; Isenman, David E; Meri, Seppo; Goldman, Adrian; Jokiranta, T Sakari

    2011-02-15

    The alternative pathway of complement is important in innate immunity, attacking not only microbes but all unprotected biological surfaces through powerful amplification. It is unresolved how host and nonhost surfaces are distinguished at the molecular level, but key components are domains 19-20 of the complement regulator factor H (FH), which interact with host (i.e., nonactivator surface glycosaminoglycans or sialic acids) and the C3d part of C3b. Our structure of the FH19-20:C3d complex at 2.3-Å resolution shows that FH19-20 has two distinct binding sites, FH19 and FH20, for C3b. We show simultaneous binding of FH19 to C3b and FH20 to nonactivator surface glycosaminoglycans, and we show that both of these interactions are necessary for full binding of FH to C3b on nonactivator surfaces (i.e., for target discrimination). We also show that C3d could replace glycosaminoglycan binding to FH20, thus providing a feedback control for preventing excess C3b deposition and complement amplification. This explains the molecular basis of atypical hemolytic uremic syndrome, where mutations on the binding interfaces between FH19-20 and C3d or between FH20 and glycosaminoglycans lead to complement attack against host surfaces.

  3. 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.

  4. Additive Factors Do Not Imply Discrete Processing Stages: A Worked Example Using Models of the Stroop Task

    PubMed Central

    Stafford, Tom; Gurney, Kevin N.

    2011-01-01

    Previously, it has been shown experimentally that the psychophysical law known as Piéron’s Law holds for color intensity and that the size of the effect is additive with that of Stroop condition (Stafford et al., 2011). According to the additive factors method (Donders, 1868–1869/1969; Sternberg, 1998), additivity is assumed to indicate independent and discrete processing stages. We present computational modeling work, using an existing Parallel Distributed Processing model of the Stroop task (Cohen et al., 1990) and a standard model of decision making (Ratcliff, 1978). This demonstrates that additive factors can be successfully accounted for by existing single stage models of the Stroop effect. Consequently, it is not valid to infer either discrete stages or separate loci of effects from additive factors. Further, our modeling work suggests that information binding may be a more important architectural property for producing additive factors than discrete stages. PMID:22102842

  5. Proteome-scale identification and characterization of mitochondria targeting proteins of Mycobacterium avium subspecies paratuberculosis: Potential virulence factors modulating host mitochondrial function.

    PubMed

    Rana, Aarti; Kumar, Devender; Rub, Abdur; Akhter, Yusuf

    2015-07-01

    Mycobacterium avium subsp. paratuberculosis is the etiological agent of Johne's Disease among ruminants. During the course of infection, it expresses a number of proteins for its successful persistence inside the host that cause variety of physiological abnormalities in the host. Mitochondrion is one of the attractive targets for pathogenic bacteria. Employing a proteome-wide sequence and structural signature based approach we have identified 46 M. avium subsp. paratuberculosis proteins as potential targets for the host mitochondrial targeting. These may act as virulence factors modulating mitochondrial physiology for bacterial survival and immune evasion inside the host cells.

  6. 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

  7. 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

  8. 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

  9. Listeria monocytogenes PrsA2 Is Required for Virulence Factor Secretion and Bacterial Viability within the Host Cell Cytosol▿

    PubMed Central

    Alonzo, Francis; Freitag, Nancy E.

    2010-01-01

    In the course of establishing its replication niche within the cytosol of infected host cells, the facultative intracellular bacterial pathogen Listeria monocytogenes must efficiently regulate the secretion and activity of multiple virulence factors. L. monocytogenes encodes two predicted posttranslocation secretion chaperones, PrsA1 and PrsA2, and evidence suggests that PrsA2 has been specifically adapted for bacterial pathogenesis. PrsA-like chaperones have been identified in a number of Gram-positive bacteria, where they are reported to function at the bacterial membrane-cell wall interface to assist in the folding of proteins translocated across the membrane; in some cases, these proteins have been found to be essential for bacterial viability. In this study, the contributions of PrsA2 and PrsA1 to L. monocytogenes growth and protein secretion were investigated in vitro and in vivo. Neither PrsA2 nor PrsA1 was found to be essential for L. monocytogenes growth in broth culture; however, optimal bacterial viability was found to be dependent upon PrsA2 for L. monocytogenes located within the cytosol of host cells. Proteomic analyses of prsA2 mutant strains in the presence of a mutationally activated allele of the virulence regulator PrfA revealed a critical requirement for PrsA2 activity under conditions of PrfA activation, an event which normally takes place within the host cell cytosol. Despite a high degree of amino acid similarity, no detectable degree of functional overlap was observed between PrsA2 and PrsA1. Our results indicate a critical requirement for PrsA2 under conditions relevant to host cell infection. PMID:20823208

  10. 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

  11. Quantitative proteomic identification of host factors involved in the Salmonella typhimurium infection cycle.

    PubMed

    Kaloyanova, Dora; Vogels, Mijke; van Balkom, Bas W M; Helms, J Bernd

    2015-01-01

    Quantitative proteomics, based on stable isotope labeling by amino acids in cell culture (SILAC), can be used to identify host proteins involved in the intracellular interplay with pathogens. This method allows identification of proteins subject to degradation or upregulation in response to intracellular infection. It can also be used to study intracellular dynamics (trafficking) of proteins in response to the infection. Here, we describe the analysis of changes in protein profiles determined in Golgi-enriched fractions isolated from cells that were either mock-infected or infected with Salmonella typhimurium. Using the SILAC approach we were able to identify 105 proteins in Golgi-enriched fractions that were significantly changed in their abundance as a result of Salmonella infection.

  12. 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

  13. Additive cytotoxicity of different monoclonal antibody-cobra venom factor conjugates for human neuroblastoma cells.

    PubMed

    Juhl, H; Petrella, E C; Cheung, N K; Bredehorst, R; Vogel, C W

    1997-11-01

    Insufficient numbers of antigen molecules and heterogeneity of antigen expression on tumor cells are major factors limiting the immunotherapeutic potential of the few clinically useful monoclonal antibodies capable of mediating complement cytotoxicity and antibody-dependent cellular cytotoxicity. To overcome this limitation, we converted two non-cytotoxic monoclonal anti-neuroblastoma antibodies, designated 3E7 (IgG2b) and 8H9 (IgG1), and the non-cytotoxic F(ab')2 fragment of the cytotoxic monoclonal anti-GD2 antibody 3F8 (IgG3) into cytotoxic antibody conjugates by covalent attachment of cobra venom factor (CVF), a structural and functional homologue of the activated third component of complement. Competitive binding experiments confirmed the different specificities of the three antibodies. In the presence of human complement, all three antibody-CVF conjugates mediated selective complement-dependent lysis of human neuroblastoma cells. Consistent with the kinetics of the alternative pathway of complement, approximately seven hours incubation were required to reach maximum cytotoxicity of up to 25% for the 3E7-CVF conjugate, up to 60% for the 8H9-CVF conjugate, and up to 95% for the 3F8 F(ab')2-CVF conjugate. The different extent of maximal cytotoxic activity of the three conjugates was reflected by corresponding differences in the extent of binding of both unconjugated antibodies and the respective conjugates. Any combination of the three antibody-CVF conjugates caused an additive effect in complement-mediated lysis. Using a cocktail of all three conjugates, the extent of complement-mediated killing could be increased up to 100%. These data demonstrate that by coupling of CVF the relative large number of non-cytotoxic monoclonal anti-tumor antibodies of interesting specificity can be used to design cocktails of cytotoxic conjugates and, thereby, to overcome the problem of insufficient and heterogeneous antigen expression on tumor cells for immunotherapy.

  14. 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

  15. 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

  16. Specific requirement for translation initiation factor 4E or its isoform drives plant host susceptibility to Tobacco etch virus

    PubMed Central

    2014-01-01

    Background In plants, eIF4E translation initiation factors and their eIFiso4E isoforms are essential susceptibility factors for many RNA viruses, including potyviruses. Mutations altering these factors are a major source of resistance to the viruses. The eIF4E allelic series is associated with specific resistance spectra in crops such as Capsicum annum. Genetic evidence shows that potyviruses have a specific requirement for a given 4E isoform that depends on the host plant. For example, Tobacco etch virus (TEV) uses eIF4E1 to infect Capsicum annuum but uses eIFiso4E to infect Arabidopsis thaliana. Here, we investigated how TEV exploits different translation initiation factor isoforms to infect these two plant species. Results A complementation system was set up in Arabidopsis to test the restoration of systemic infection by TEV. Using this system, Arabidopsis susceptibility to TEV was complemented with a susceptible pepper eIF4E1 allele but not with a resistant allele. Therefore, in Arabidopsis, TEV can use the pepper eIF4E1 instead of the endogenous eIFiso4E isoform so is able to switch between translation initiation factor 4E isoform to infect the same host. Moreover, we show that overexpressing the pepper eIF4E1 alleles is sufficient to make Arabidopsis susceptible to an otherwise incompatible TEV strain. Lastly, we show that the resistant eIF4E1 allele is similarly overcome by a resistance-breaking TEV strain as in pepper, confirming that this Arabidopsis TEV-susceptibility complementation system is allele-specific. Conclusion We report here a complementation system in Arabidopsis that makes it possible to assess the role of pepper pvr2-eIF4E alleles in susceptibility to TEV. Heterologous complementation experiments showed that the idiosyncratic properties of the 4E and iso4E proteins create a major checkpoint for viral infection of different hosts. This system could be used to screen natural or induced eIF4E alleles to find and study alleles of interest for

  17. 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

  18. Serratia marcescens suppresses host cellular immunity via the production of an adhesion-inhibitory factor against immunosurveillance cells.

    PubMed

    Ishii, Kenichi; Adachi, Tatsuo; Hamamoto, Hiroshi; Sekimizu, Kazuhisa

    2014-02-28

    Injection of a culture supernatant of Serratia marcescens into the bloodstream of the silkworm Bombyx mori increased the number of freely circulating immunosurveillance cells (hemocytes). Using a bioassay with live silkworms, serralysin metalloprotease was purified from the culture supernatant and identified as the factor responsible for this activity. Serralysin inhibited the in vitro attachment of both silkworm hemocytes and murine peritoneal macrophages. Incubation of silkworm hemocytes or murine macrophages with serralysin resulted in degradation of the cellular immune factor BmSPH-1 or calreticulin, respectively. Furthermore, serralysin suppressed in vitro phagocytosis of bacteria by hemocytes and in vivo bacterial clearance in silkworms. Disruption of the ser gene in S. marcescens attenuated its host killing ability in silkworms and mice. These findings suggest that serralysin metalloprotease secreted by S. marcescens suppresses cellular immunity by decreasing the adhesive properties of immunosurveillance cells, thereby contributing to bacterial pathogenesis.

  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. 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.

  1. Wolbachia as an “Infectious” Extrinsic Factor Manipulating Host Signaling Pathways

    PubMed Central

    Negri, Ilaria

    2011-01-01

    Wolbachia pipientis is a widespread endosymbiont of filarial nematodes and arthropods. While in worms the symbiosis is obligate, in arthropods Wolbachia induces several reproductive manipulations (i.e., cytoplasmic incompatibility, parthenogenesis, feminization of genetic males, and male-killing) in order to increase the number of infected females. These various phenotypic effects may be linked to differences in host physiology, and in particular to endocrine-related processes governing growth, development, and reproduction. Indeed, a number of evidences links Wolbachia symbiosis to insulin and ecdysteroid signaling, two multilayered pathways known to work antagonistically, jointly or even independently for the regulation of different molecular networks. At present it is not clear whether Wolbachia manipulates one pathway, thus affecting other related metabolic networks, or if it targets both pathways, even interacting at several points in each of them. Interestingly, in view of the interplay between hormone signaling and epigenetic machinery, a direct influence of the “infection” on hormonal signaling involving ecdysteroids might be achievable through the manipulation of the host’s epigenetic pathways. PMID:22654845

  2. 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

  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. Interaction with host factors exacerbates Trypanosoma cruzi cell invasion capacity upon oral infection.

    PubMed

    Covarrubias, Charles; Cortez, Mauro; Ferreira, Daniele; Yoshida, Nobuko

    2007-12-01

    Outbreaks of severe acute Chagas' disease acquired by oral infection, leading to death in some cases, have occurred in recent years. Using the mouse model, we investigated the basis of such virulence by analyzing a Trypanosoma cruzi isolate, SC, from a patient with severe acute clinical symptoms, who was infected by oral route. It has previously been shown that, upon oral inoculation into mice, T. cruzi metacyclic trypomastigotes invade the gastric mucosal epithelium by engaging the stage-specific surface glycoprotein gp82, whereas the surface molecule gp90 functions as a down-modulator of cell invasion. We found that, when orally inoculated into mice, metacyclic forms of the SC isolate, which express high levels of gp90, produced high parasitemias and high mortality, in sharp contrast with the reduced infectivity in vitro. Upon recovery from the mouse stomach 1h after oral inoculation, the gp90 molecule of the parasites was completely degraded, and their entry into HeLa cells, as well as into Caco-2 cells, was increased. The gp82 molecule was more resistant to digestive action of the gastric juice. Host cell invasion of SC isolate metacyclic trypomastigotes was augmented in the presence of gastric mucin. No alteration in infectivity was observed in T. cruzi strains CL and G which were used as references and which express gp90 molecules resistant to degradation by gastric juice. Taken together, our findings suggest that the exacerbation of T. cruzi infectivity, such as observed upon interaction of the SC isolate with the mouse stomach components, may be responsible for the severity of acute Chagas' disease that has been reported in outbreaks of oral T. cruzi infection.

  5. Mechanisms employed by retroviruses to exploit host factors for translational control of a complicated proteome.

    PubMed

    Bolinger, Cheryl; Boris-Lawrie, Kathleen

    2009-01-01

    Retroviruses have evolved multiple strategies to direct the synthesis of a complex proteome from a single primary transcript. Their mechanisms are modulated by a breadth of virus-host interactions, which are of significant fundamental interest because they ultimately affect the efficiency of virus replication and disease pathogenesis. Motifs located within the untranslated region (UTR) of the retroviral RNA have established roles in transcriptional trans-activation, RNA packaging, and genome reverse transcription; and a growing literature has revealed a necessary role of the UTR in modulating the efficiency of viral protein synthesis. Examples include a 5' UTR post-transcriptional control element (PCE), present in at least eight retroviruses, that interacts with cellular RNA helicase A to facilitate cap-dependent polyribosome association; and 3' UTR constitutive transport element (CTE) of Mason-Pfizer monkey virus that interacts with Tap/NXF1 and SR protein 9G8 to facilitate RNA export and translational utilization. By contrast, nuclear protein hnRNP E1 negatively modulates HIV-1 Gag, Env, and Rev protein synthesis. Alternative initiation strategies by ribosomal frameshifting and leaky scanning enable polycistronic translation of the cap-dependent viral transcript. Other studies posit cap-independent translation initiation by internal ribosome entry at structural features of the 5' UTR of selected retroviruses. The retroviral armamentarium also commands mechanisms to counter cellular post-transcriptional innate defenses, including protein kinase R, 2',5'-oligoadenylate synthetase and the small RNA pathway. This review will discuss recent and historically-recognized insights into retrovirus translational control. The expanding knowledge of retroviral post-transcriptional control is vital to understanding the biology of the retroviral proteome. In a broad perspective, each new insight offers a prospective target for antiviral therapy and strategic improvement of gene

  6. 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

  7. The integration host factor of Escherichia coli binds to multiple sites at plasmid R6K gamma origin and is essential for replication.

    PubMed Central

    Filutowicz, M; Appelt, K

    1988-01-01

    Examination of the effect of the himA and himD mutants of E. coli on the maintenance of plasmid R6K has revealed that the gamma origin-containing replicons cannot be established in any of the mutants deficient in the production of E. coli Integration Host Factor (IHF). Contrary, the R6K derivatives containing other origins of the plasmid (alpha and/or beta) replicate in a host lacking functional IHF protein. We show that IHF protein binds specifically to a segment of the replication region which is essential for the activity of all three R6K origins. Mapping the IHF binding sequence with neocarzinostatin showed that the protein protects three segments of the origin: two strong binding sites reside within an AT-rich block, while the third, considerably weaker site is separated from the other two by a cluster of the seven 22 bp direct repeats. These seven repeats have been shown previously to bind the R6K-encoded initiator protein pi. We also demonstrate that the establishment of pi-origin complexes prior to IHF addition prevents the binding of the IHF protein to the gamma origin. The binding sequences of IHF and pi proteins do not overlap, therefore, we propose that the binding of pi protein alters the structure of the DNA and thereby prevents the subsequent binding of IHF protein. Images PMID:2967465

  8. 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

    ... EDUCATION DISABILITY AND REHABILITATION RESEARCH: SPECIAL PROJECTS AND DEMONSTRATIONS FOR SPINAL CORD INJURIES How Does the Secretary Make a Grant? § 359.32 What additional factors does the Secretary...

  9. 34 CFR 359.32 - What additional factors does the Secretary consider in making a grant under this program?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... EDUCATION DISABILITY AND REHABILITATION RESEARCH: SPECIAL PROJECTS AND DEMONSTRATIONS FOR SPINAL CORD INJURIES How Does the Secretary Make a Grant? § 359.32 What additional factors does the Secretary...

  10. 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

    ... EDUCATION DISABILITY AND REHABILITATION RESEARCH: SPECIAL PROJECTS AND DEMONSTRATIONS FOR SPINAL CORD INJURIES How Does the Secretary Make a Grant? § 359.32 What additional factors does the Secretary...

  11. 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

    ... EDUCATION DISABILITY AND REHABILITATION RESEARCH: SPECIAL PROJECTS AND DEMONSTRATIONS FOR SPINAL CORD INJURIES How Does the Secretary Make a Grant? § 359.32 What additional factors does the Secretary...

  12. 34 CFR 359.32 - What additional factors does the Secretary consider in making a grant under this program?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... EDUCATION DISABILITY AND REHABILITATION RESEARCH: SPECIAL PROJECTS AND DEMONSTRATIONS FOR SPINAL CORD INJURIES How Does the Secretary Make a Grant? § 359.32 What additional factors does the Secretary...

  13. 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

  14. [Factors involved in host-pathogen interaction for the risk of Hodgkin lymphoma induced by Epstein Barr virus].

    PubMed

    Torres Espíndola, Luz María; Arellano Galindo, José; Velazquez Cruz, Rafael; Castillejos López, Manuel de Jesús

    2013-09-01

    Hodgkin lymphoma (HL) is a neoplasm characterized by malignant cells called Reed Sternberg and Hodgkin's cells in the lymphatic system. Such cells comprise 1% of the tumor while the remainder is made up of lymphocytes, histiocytes, eosinophils and plasma non-neoplastic cells. The annual global incidence of HL is 3-10/100,000 inhabitants and is most commonly found in young adults. The mechanism by which cell transformation is accomplished is not entirely clear; however, some evidences suggest that oncogenic viruses like the Epstein Barr virus (EBV) may have a high impact on the pathogenesis of lymphoproliferation. Genetic and environmental factors could be involved, since it has been found a high incidence of HL among members of the same family. In Mexico, there have been studies to determine the prevalence of EBV in patients with HL and found the presence of this virus in up to 64.2% of the cases. EBV has been detected in the Reed Sternberg cells and Hodgkin cells in 50% of cases of classical HL. There is not a satisfactory explanation for this, but it has been proposed that geographic and immunological variabilities play a role in the positivity of EBV in HL. However, despite recent advances in the field, there is insufficient evidence to show a clear association between host factors, environment and pathogens, and the risk of lymphoproliferation leading to the development of HL. This review aims to give an overview about the risk factors that influence the interaction of host, pathogens and environment in the etiology of HL.

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

    PubMed

    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.

  16. Genomic analysis of host - Peste des petits ruminants vaccine viral transcriptome uncovers transcription factors modulating immune regulatory pathways.

    PubMed

    Manjunath, Siddappa; Kumar, Gandham Ravi; Mishra, Bishnu Prasad; Mishra, Bina; Sahoo, Aditya Prasad; Joshi, Chaitanya G; Tiwari, Ashok K; Rajak, Kaushal Kishore; Janga, Sarath Chandra

    2015-01-01

    Peste des petits ruminants (PPR), is an acute transboundary viral disease of economic importance, affecting goats and sheep. Mass vaccination programs around the world resulted in the decline of PPR outbreaks. Sungri 96 is a live attenuated vaccine, widely used in Northern India against PPR. This vaccine virus, isolated from goat works efficiently both in sheep and goat. Global gene expression changes under PPR vaccine virus infection are not yet well defined. Therefore, in this study we investigated the host-vaccine virus interactions by infecting the peripheral blood mononuclear cells isolated from goat with PPRV (Sungri 96 vaccine virus), to quantify the global changes in the transcriptomic signature by RNA-sequencing. Viral genome of Sungri 96 vaccine virus was assembled from the PPRV infected transcriptome confirming the infection and demonstrating the feasibility of building a complete non-host genome from the blood transcriptome. Comparison of infected transcriptome with control transcriptome revealed 985 differentially expressed genes. Functional analysis showed enrichment of immune regulatory pathways under PPRV infection. Key genes involved in immune system regulation, spliceosomal and apoptotic pathways were identified to be dysregulated. Network analysis revealed that the protein - protein interaction network among differentially expressed genes is significantly disrupted in infected state. Several genes encoding TFs that govern immune regulatory pathways were identified to co-regulate the differentially expressed genes. These data provide insights into the host - PPRV vaccine virus interactome for the first time. Our findings suggested dysregulation of immune regulatory pathways and genes encoding Transcription Factors (TFs) that govern these pathways in response to viral infection. PMID:25827022

  17. 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

  18. 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

  19. 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.

  20. Interactions of HIV and drugs of abuse: the importance of glia, neural progenitors, and host genetic factors.

    PubMed

    Hauser, Kurt F; Knapp, Pamela E

    2014-01-01

    Considerable insight has been gained into the comorbid, interactive effects of HIV and drug abuse in the brain using experimental models. This review, which considers opiates, methamphetamine, and cocaine, emphasizes the importance of host genetics and glial plasticity in driving the pathogenic neuron remodeling underlying neuro-acquired immunodeficiency syndrome and drug abuse comorbidity. Clinical findings are less concordant than experimental work, and the response of individuals to HIV and to drug abuse can vary tremendously. Host-genetic variability is important in determining viral tropism, neuropathogenesis, drug responses, and addictive behavior. However, genetic differences alone cannot account for individual variability in the brain "connectome." Environment and experience are critical determinants in the evolution of synaptic circuitry throughout life. Neurons and glia both exercise control over determinants of synaptic plasticity that are disrupted by HIV and drug abuse. Perivascular macrophages, microglia, and to a lesser extent astroglia can harbor the infection. Uninfected bystanders, especially astroglia, propagate and amplify inflammatory signals. Drug abuse by itself derails neuronal and glial function, and the outcome of chronic exposure is maladaptive plasticity. The negative consequences of coexposure to HIV and drug abuse are determined by numerous factors including genetics, sex, age, and multidrug exposure. Glia and some neurons are generated throughout life, and their progenitors appear to be targets of HIV and opiates/psychostimulants. The chronic nature of HIV and drug abuse appears to result in sustained alterations in the maturation and fate of neural progenitors, which may affect the balance of glial populations within multiple brain regions.

  1. 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

  2. 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

  3. 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.

  4. 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

  5. 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

  6. Both Host and Pathogen Factors Predispose to Escherichia coli Urinary-Source Bacteremia in Hospitalized Patients

    PubMed Central

    Marschall, Jonas; Zhang, Lixin; Foxman, Betsy; Warren, David K.; Henderson, Jeffrey P.

    2012-01-01

    Background. The urinary tract is the most common source for Escherichia coli bacteremia. Mortality from E. coli urinary-source bacteremia is higher than that from urinary tract infection. Predisposing factors for urinary-source E. coli bacteremia are poorly characterized. Methods. In order to identify urinary-source bacteremia risk factors, we conducted a 12-month prospective cohort study of adult inpatients with E. coli bacteriuria that were tested for bacteremia within ±1 day of the bacteriuria. Patients with bacteremia were compared with those without bacteremia. Bacterial isolates from urine were screened for 16 putative virulence genes using high-throughput dot-blot hybridization. Results. Twenty-four of 156 subjects (15%) had E. coli bacteremia. Bacteremic patients were more likely to have benign prostatic hyperplasia (56% vs 19%; P = .04), a history of urogenital surgery (63% vs 28%; P = .001), and presentation with hesitancy/retention (21% vs 4%; P = .002), fever (63% vs 38%; P = .02), and pyelonephritis (67% vs 41%; P = .02). The genes kpsMT (group II capsule) (17 [71%] vs 62 [47%]; P = .03) and prf (P-fimbriae family) (13 [54%] vs 40 [30%]; P = .02) were more frequent in the urinary strains from bacteremic patients. Symptoms of hesitancy/retention (odds ratio [OR], 7.8; 95% confidence interval [CI], 1.6–37), history of a urogenital procedure (OR, 5.4; 95% CI, 2–14.7), and presence of kpsMT (OR, 2.9; 95% CI, 1–8.2) independently predicted bacteremia. Conclusions. Bacteremia secondary to E. coli bacteriuria was frequent (15%) in those tested for it. Urinary stasis, surgical disruption of urogenital tissues, and a bacterial capsule characteristic contribute to systemic invasion by uropathogenic E. coli. PMID:22431806

  7. 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

  8. 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.

  9. [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.

  10. 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

  11. Angiogenic factors are associated with development of acute graft-versus-host disease after allogeneic hematopoietic stem cell transplantation.

    PubMed

    Nie, Di-min; Wu, Qiu-ling; Zhu, Xia-xia; Zhang, Ran; Zheng, Peng; Fang, Jun; You, Yong; Zhong, Zhao-dong; Xia, Ling-hui; Hong, Mei

    2015-10-01

    Acute graft-versus-host disease (aGVHD) is a serious complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, the mechanisms of aGVHD are not well understood. We aim to investigate the roles of the three angiogenic factors: angiopoietin-1 (Ang-1), Ang-2 and vascular endothelial growth factor (VEGF) in the development of aGVHD. Twenty-one patients who underwent allo-HSCT were included in our study. The dynamic changes of Ang-1, Ang-2 and VEGF were monitored in patients before and after allo-HSCT. In vitro, endothelial cells (ECs) were treated with TNF-β in the presence or absence of Ang-1, and then the Ang-2 level in the cell culture medium and the tubule formation by ECs were evaluated. After allo-HSCT, Ang-1, Ang-2 and VEGF all exhibited significant variation, suggesting these factors might be involved in the endothelial damage in transplantation. Patients with aGVHD had lower Ang-1 level at day 7 but higher Ang-2 level at day 21 than those without aGVHD, implying that Ang-1 may play a protective role in early phase yet Ang-2 is a promotion factor to aGVHD. In vitro, TNF-β promoted the release of Ang-2 by ECs and impaired tubule formation of ECs, which were both weakened by Ang-1, suggesting that Ang-1 may play a protective role in aGVHD by influencing the secretion of Ang-2, consistent with our in vivo tests. It is concluded that monitoring changes of these factors following allo-HSCT might help to identify patients at a high risk for aGVHD. PMID:26489624

  12. 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

  13. 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.

  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. 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.

  16. 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

  17. 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.

  18. 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

  19. 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

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

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ..., such as a password or response to a challenge question. (2) Something the practitioner is, biometric... modules or one-time-password devices. (c) If one factor is a biometric, the biometric subsystem...

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

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., such as a password or response to a challenge question. (2) Something the practitioner is, biometric... modules or one-time-password devices. (c) If one factor is a biometric, the biometric subsystem...

  2. MgtC as a Host-Induced Factor and Vaccine Candidate against Mycobacterium abscessus Infection.

    PubMed

    Le Moigne, Vincent; Belon, Claudine; Goulard, Céline; Accard, Geoffrey; Bernut, Audrey; Pitard, Bruno; Gaillard, Jean-Louis; Kremer, Laurent; Herrmann, Jean-Louis; Blanc-Potard, Anne-Béatrice

    2016-10-01

    Mycobacterium abscessus is an emerging pathogenic mycobacterium involved in pulmonary and mucocutaneous infections, presenting a serious threat for patients with cystic fibrosis (CF). The lack of an efficient treatment regimen and the emergence of multidrug resistance in clinical isolates require the development of new therapeutic strategies against this pathogen. Reverse genetics has revealed genes that are present in M. abscessus but absent from saprophytic mycobacteria and that are potentially involved in pathogenicity. Among them, MAB_3593 encodes MgtC, a known virulence factor involved in intramacrophage survival and adaptation to Mg(2+) deprivation in several major bacterial pathogens. Here, we demonstrated a strong induction of M. abscessus MgtC at both the transcriptional and translational levels when bacteria reside inside macrophages or upon Mg(2+) deprivation. Moreover, we showed that M. abscessus MgtC was recognized by sera from M. abscessus-infected CF patients. The intramacrophage growth (J774 or THP1 cells) of a M. abscessus knockout mgtC mutant was, however, not significantly impeded. Importantly, our results indicated that inhibition of MgtC in vivo through immunization with M. abscessus mgtC DNA, formulated with a tetrafunctional amphiphilic block copolymer, exerted a protective effect against an aerosolized M. abscessus challenge in CF (ΔF508 FVB) mice. The formulated DNA immunization was likely associated with the production of specific MgtC antibodies, which may stimulate a protective effect by counteracting MgtC activity during M. abscessus infection. These results emphasize the importance of M. abscessus MgtC in vivo and provide a basis for the development of novel therapeutic tools against pulmonary M. abscessus infections in CF patients. PMID:27481243

  3. 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

  4. 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

  5. Host risk factors, ultraviolet index of residence, and incident malignant melanoma in situ among US women and men.

    PubMed

    Walls, Andrew C; Han, Jiali; Li, Tricia; Qureshi, Abrar A

    2013-05-01

    The incidences of malignant melanoma in situ (MMIS) and invasive malignant melanoma are rising in the United States, but few studies have examined risk factors for MMIS. We evaluated the risk of MMIS according to the host phenotype and the ultraviolet index of the state of residence. Prospective data were collected via biennial questionnaires from 250,151 women and men aged ≥20 years in the Nurses' Health Study (1980-2008), the Nurses' Health Study 2 (1989-2009), and the Health Professionals Follow-up Study (1986-2008). During 7,144,820 person-years of follow-up, 888 incident MMIS lesions occurred, representing 33% of all incident malignant melanoma. Meta-analysis across the cohorts demonstrated that the presence of multiple nevi on the extremities conferred the highest relative risk for MMIS (relative risk = 3.18, 95% confidence interval: 2.59, 3.90). Family history of melanoma, number of severe sunburns, sunburn susceptibility, hair color, and Fitzpatrick skin types I, II, and III were significantly associated with an increased risk of MMIS. Conversely, the ultraviolet index of the state of residence at birth, at age 15 years, and at age 30 years was not associated with increased risk of MMIS. Continued study of MMIS and associated risk factors will help identify persons who are most at risk and elucidate the role of MMIS within the spectrum of cutaneous melanoma. PMID:23579556

  6. Salmonella typhimurium's transthyretin-like protein is a host-specific factor important in fecal survival in chickens.

    PubMed

    Hennebry, Sarah C; Sait, Leanne C; Mantena, Raju; Humphrey, Thomas J; Yang, Ji; Scott, Timothy; Kupz, Andreas; Richardson, Samantha J; Strugnell, Richard A

    2012-01-01

    The transthyretin-like protein (TLP) from Salmonella enterica subspecies I is a periplasmic protein with high level structural similarity to a protein found in mammals and fish. In humans, the protein homologue, transthyretin, binds and carries retinol and thyroxine, and a series of other, unrelated aromatic compounds. Here we show that the amino acid sequence of the TLP from different species, subspecies and serovars of the Salmonella genus is highly conserved and demonstrate that the TLP gene is constitutively expressed in S. Typhimurium and that copper and other divalent metal ions severely inhibit enzyme activity of the TLP, a cyclic amidohydrolase that hydrolyses 5-hydroxyisourate (5-HIU). In order to determine the in vivo role of the S. Typhimurium TLP, we constructed a strain of mouse-virulent S. Typhimurium SL1344 bearing a mutation in the TLP gene (SL1344 ΔyedX). We assessed the virulence of this strain via oral inoculation of mice and chickens. Whilst SL1344 ΔyedX induced a systemic infection in both organisms, the bacterial load detected in the faeces of infected chickens was significantly reduced when compared to the load of S. Typhimurium SL1344. These data demonstrate that the TLP gene is required for survival of S. Typhimurium in a high uric acid environment such as chicken faeces, and that metabolic traits of Salmonellae in natural and contrived hosts may be fundamentally different. Our data also highlight the importance of using appropriate animal models for the study of bacterial pathogenesis especially where host-specific virulence factors or traits are the subject of the study.

  7. 21 CFR 1311.115 - Additional requirements for two-factor authentication.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) separate from the computer to which the practitioner is gaining access. (b) If one factor is a hard token, it must be separate from the computer to which it is gaining access and must meet at least the criteria of FIPS 140-2 Security Level 1, as incorporated by reference in § 1311.08, for...

  8. The effect of nutritional additives on anti-infective factors in human milk.

    PubMed

    Quan, R; Yang, C; Rubinstein, S; Lewiston, N J; Stevenson, D K; Kerner, J A

    1994-06-01

    It has become a common practice to supplement human milk with a variety of additives to improve the nutritive content of the feeding for the premature infant. Twenty-two freshly frozen human milk samples were measured for lysozyme activity, total IgA, and specific IgA to Escherichia coli serotypes 01, 04, and 06. One mL aliquots were mixed with the following: 1 mL of Similac, Similac Special Care, Enfamil, Enfamil Premature Formula, and sterile water; 33 mL of Poly-Vi-Sol, 33 mg of Moducal, and 38 mg of breast-milk fortifier, and then reanalyzed. Significant decreases (41% to 74%) in lysozyme activity were seen with the addition of all formulas; breast-milk fortifier reduced activity by 19%, while no differences were seen with Moducal, sterile water, or Poly-Vi-Sol. No differences were seen in total IgA content, but some decreases were seen in specific IgA to E. coli serotypes 04 and 06. E. coli growth was determined after 3 1/2 hours of incubation at 37 degrees C after mixing. All cow-milk formulas enhanced E. coli growth; soy formulas and other additives preserved inhibition of bacterial growth. Nutritional additives can impair anti-infective properties of human milk, and such interplay should be considered in the decision on the feeding regimen of premature infants.

  9. 34 CFR 377.22 - What additional factors does the Secretary consider in making grants?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION DEMONSTRATION PROJECTS TO INCREASE CLIENT CHOICE PROGRAM How Does the Secretary Make an Award? § 377.22 What additional... strategies to increase client choice, in order to ensure that a variety of approaches are demonstrated...

  10. 34 CFR 377.22 - What additional factors does the Secretary consider in making grants?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION DEMONSTRATION PROJECTS TO INCREASE CLIENT CHOICE PROGRAM How Does the Secretary Make an Award? § 377.22 What additional... strategies to increase client choice, in order to ensure that a variety of approaches are demonstrated...

  11. Genome-wide screening and identification of factors affecting the biosynthesis of prodigiosin by Hahella chejuensis, using Escherichia coli as a surrogate host.

    PubMed

    Kwon, Soon-Kyeong; Park, Yon-Kyoung; Kim, Jihyun F

    2010-03-01

    A marine bacterium, Hahella chejuensis, recently has attracted attention due to its lytic activity against a red-tide dinoflagellate. The algicidal function originates from its red pigment, prodigiosin, which also exhibits immunosuppressive or anticancer activity. Genome sequencing and functional analysis revealed a gene set contained in the hap gene cluster that is responsible for the biosynthesis of prodigiosin. To screen for the factors affecting the prodigiosin biosynthesis, we constructed a plasmid library of the H. chejuensis genomic DNA, introduced it into Escherichia coli strains harboring the hap cluster, and observed changes in production of the red pigment. Among the screened clones, hapXY genes whose products constitute a two-component signal transduction system were elucidated as positive regulators of the pigment production. In addition, an Hfq-dependent, noncoding region located at one end of the hap cluster was confirmed to play roles in regulation. Identification of factors involved in the regulation of prodigiosin biosynthesis should help in understanding how the prodigiosin-biosynthetic pathway is organized and controlled and also aid in modulating the overexpression of prodigiosin in a heterologous host, such as E. coli, or in the natural producer, H. chejuensis.

  12. 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

  13. Identification of the key weather factors affecting overwintering success of Apolygus lucorum eggs in dead host tree branches.

    PubMed

    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.

  14. 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

  15. 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

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

    PubMed

    Wang, Bei; Zhang, Xiaoyu; Zhao, Zhendong

    2013-08-01

    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.

  17. 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

  18. 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.

  19. Decellularized allogeneic and xenogeneic tissue as a bioscaffold for regenerative medicine: factors that influence the host response.

    PubMed

    Badylak, Stephen F

    2014-07-01

    Biologic scaffold materials composed of mammalian extracellular matrix (ECM) are prepared by decellularization of source tissues harvested from either humans (allogeneic) or a variety of other (xenogeneic) species. These matrix scaffold materials are commonly regulated and used as surgical mesh materials for applications such as ventral hernia repair, musculotendinous tissue reconstruction, dura mater replacement, reconstructive breast surgery, pelvic floor reconstruction, and the treatment of cutaneous ulcers, among others. The clinical results for these applications vary widely for reasons which include characteristics of the source tissue, methods and efficacy of tissue decellularization, and methods of processing/manufacturing. However, the primary determinant of success or failure in the clinical setting is the response of the host to these implanted biologic scaffold materials. It is logical to question why any non-self biologic material, particularly a xenogeneic material, would not elicit an early and aggressive adverse immune response. The present manuscript briefly describes the known mechanisms by which these biologic scaffold materials can facilitate a constructive remodeling response, the known causative factors of an adverse response, and provides a general discussion of the role of the macrophage in determining outcome.

  20. Simultaneous Identification of Potential Pathogenicity Factors of Mycoplasma agalactiae in the Natural Ovine Host by Negative Selection.

    PubMed

    Hegde, Shivanand; Hegde, Shrilakshmi; Zimmermann, Martina; Flöck, Martina; Spergser, Joachim; Rosengarten, Renate; Chopra-Dewasthaly, Rohini

    2015-07-01

    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

  1. Interaction between the SifA virulence factor and its host target SKIP is essential for Salmonella pathogenesis.

    PubMed

    Diacovich, Lautaro; Dumont, Audrey; Lafitte, Daniel; Soprano, Elodie; Guilhon, Aude-Agnès; Bignon, Christophe; Gorvel, Jean-Pierre; Bourne, Yves; Méresse, Stéphane

    2009-11-27

    SifA is a Salmonella effector that is translocated into infected cells by the pathogenicity island 2-encoded type 3 secretion system. SifA is a critical virulence factor. Previous studies demonstrated that, upon translocation, SifA binds the pleckstrin homology motif of the eukaryotic host protein SKIP. In turn, the SifA-SKIP complex regulates the mobilization of the molecular motor kinesin-1 on the bacterial vacuole. SifA exhibits multiple domains containing functional motifs. Here we performed a molecular dissection and a mutational study of SifA to evaluate the relative contribution of the different domains to SifA functions. Biochemical and crystallographic analysis confirmed that the N-terminal domain of SifA is sufficient to interact with the pleckstrin homology domain of SKIP, forming a 1:1 complex with a micromolar dissociation constant. Mutation of the tryptophan residue in the WXXXE motif, which has been proposed to mimic active form of GTPase, deeply affected the stability and the translocation of SifA while mutations of the glutamic residue had no functional impact. A SifA L130D mutant that does not bind SKIP showed a DeltasifA-like phenotype both in infected cells and in the mouse model of infection. We concluded that the WXXXE motif is essential for maintaining the tertiary structure of SifA, the functions of which require the interaction with the eukaryotic protein SKIP.

  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. 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

  4. Specific Photocrosslinking of DNA-Protein Complexes: Identification of Contacts Between Integration Host Factor and Its Target DNA

    NASA Astrophysics Data System (ADS)

    Yang, Shu-Wei; Nash, Howard A.

    1994-12-01

    Azide moieties have been specifically placed in the backbone of DNA by chemical coupling between azidophenacyl bromide and uniquely positioned phosphorothioate residues. The derivatized DNA forms specific complexes with a DNA-binding protein and, following irradiation with 302-nm light, makes specific crosslinks to the protein. Isolation of this covalent complex, followed by tryptic digestion and Edman degradation of the resulting crosslinked peptide, identifies the portion of the protein that is near the derivatized segment of the target DNA. We use this method to probe the interaction between a specific DNA sequence and integration host factor (IHF) protein. A single IHF heterodimer is known to contact >25 bp of DNA and thereby introduce a sharp bend. Two segments of a typical IHF site were derivatized with aryl azide. Although the segments were separated by only 5 bp, they crosslinked to different subunits of IHF. The locations of the crosslinks support our current view for the way IHF protein binds to and bends its specific targets.

  5. Effects of energy restriction and wheel running on mammary carcinogenesis and host systemic factors in a rat model.

    PubMed

    Zhu, Zongjian; Jiang, Weiqin; Zacher, Jarrod H; Neil, Elizabeth S; McGinley, John N; Thompson, Henry J

    2012-03-01

    Limiting energy availability via diet or physical activity has health benefits; however, it is not known whether these interventions have similar effects on the development of cancer. Two questions were addressed as follows: (i) Does limiting energy availability by increasing physical activity have the same effect on mammary carcinogenesis as limiting caloric intake? and (ii) Are host systemic factors, implicated as risk biomarkers for breast cancer, similarly affected by these interventions? Female Sprague Dawley rats were injected with 50-mg 1-methyl-1-nitrosourea per kg body weight at 21 days of age and randomized to one of five groups (30 rats per group) as follows: (i) sham running wheel control; (ii) restricted fed to 85% of the sham control; (iii and iv) voluntary running in a motorized activity wheel (37 m/min) to a maximum of 3,500 m/d or 1,750 m/d; and (v) sedentary ad libitum fed control with no access to a running wheel. The three energetics interventions inhibited the carcinogenic response, reducing cancer incidence (P = 0.01), cancer multiplicity (P < 0.001), and cancer burden (P < 0.001) whereas prolonging cancer latency (P = 0.004) although differences among energetics interventions were not significant. Of the plasma biomarkers associated with the development of cancer, the energetics interventions reduced bioavailable insulin-like growth factor-1 (IGF-1), insulin, interleukin-6, serum amyloid protein, TNF-α, and leptin and increased IGF-binding protein 3 (IGFBP-3) and adiponectin. Plasma-fasting glucose, C-reactive protein, estradiol, and progesterone were unaffected. The plasma biomarkers of greatest value in predicting the carcinogenic response were adiponectin > IGF-1/IGFBP-3 > IGFBP-3 > leptin > IGF-1.

  6. 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

  7. 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

  8. 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

  9. Secreted effectors of the tomato leaf mould fungus Cladosporium fulvum are virulence factors that target host defense

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cladosporium fulvum is a biotrophic fungal pathogen that causes leaf mould of tomato. Inside the leaf, C. fulvum does not penetrate host cells or develop haustoria but remains confined to the intercellular space between mesophyll cells. Ten effector proteins that are secreted during host colonizatio...

  10. Diel activity of nymphal Dermacentor occidentalis and Ixodes pacificus (Acari: Ixodidae) in relation to meteorological factors and host activity periods.

    PubMed

    Lane, R S; Kleinjan, J E; Schoeler, G B

    1995-05-01

    Relation of diel activity and questing behavior of nymphal Dermacentor occidentalis Marx and Ixodes pacificus Cooley & Kohls to meteorological factors was investigated in a shaded versus a sun-exposed outdoor arena. Oak-woodland soil covered partially with leaf litter and small rocks, and 24 vertically oriented grass stems 2.5, 5.0, 10.0, and 20.0 cm tall were provided as substrate and potential questing sites. Tick activity and weather conditions were monitored bihourly during 15 diel (24-h) experiments (D. occidentalis, 8; I. pacificus, 7). In shade, D. occidentalis was active throughout the day, but questing occurred mainly at night and in the morning on grass stems or atop soil when temperatures were cool and relative humidities high. Ticks seemed to prefer to quest at heights between approximately 4 and 10 cm. The time of day and height at which D. occidentalis quested on grass stems coincided with the activity periods and size of its lagomorph and rodent hosts. Low percentages (< or = 15%) of I. pacificus nymphs (n = 100 or 200) were active atop soil or leaf litter at night or sporadically throughout the day, but none ascended grass stems. This finding was reconfirmed by monitoring diurnal behavior of nymphs in an outdoor aquarium having leaf litter as substrate; < or = 4% of 53 ticks were detected on the topmost layer of leaves and, of those, most I. pacificus were situated on the lower versus the upper surfaces of such leaves. Activity of I. pacificus was correlated positively with relative humidity and negatively with soil temperature in one experiment. In the sun-exposed arena, ticks of both species died within 9-11 d as daytime soil-surface temperatures sometimes reached maximums of 73-77 degrees C and relative humidities dropped to 14-24%. In contrast, D. occidentalis and I. pacificus survived for up to 6 and 8 wk, respectively, in the shaded arena. After its introduction into the shaded arena, the western fence lizard (Sceloporus occidentalis Baird

  11. 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

  12. 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

  13. Insulin resistance: an additional risk factor in the pathogenesis of cardiovascular disease in type 2 diabetes.

    PubMed

    Patel, Tushar P; Rawal, Komal; Bagchi, Ashim K; Akolkar, Gauri; Bernardes, Nathalia; Dias, Danielle da Silva; Gupta, Sarita; Singal, Pawan K

    2016-01-01

    Sedentary life style and high calorie dietary habits are prominent leading cause of metabolic syndrome in modern world. Obesity plays a central role in occurrence of various diseases like hyperinsulinemia, hyperglycemia and hyperlipidemia, which lead to insulin resistance and metabolic derangements like cardiovascular diseases (CVDs) mediated by oxidative stress. The mortality rate due to CVDs is on the rise in developing countries. Insulin resistance (IR) leads to micro or macro angiopathy, peripheral arterial dysfunction, hampered blood flow, hypertension, as well as the cardiomyocyte and the endothelial cell dysfunctions, thus increasing risk factors for coronary artery blockage, stroke and heart failure suggesting that there is a strong association between IR and CVDs. The plausible linkages between these two pathophysiological conditions are altered levels of insulin signaling proteins such as IR-β, IRS-1, PI3K, Akt, Glut4 and PGC-1α that hamper insulin-mediated glucose uptake as well as other functions of insulin in the cardiomyocytes and the endothelial cells of the heart. Reduced AMPK, PFK-2 and elevated levels of NADP(H)-dependent oxidases produced by activated M1 macrophages of the adipose tissue and elevated levels of circulating angiotensin are also cause of CVD in diabetes mellitus condition. Insulin sensitizers, angiotensin blockers, superoxide scavengers are used as therapeutics in the amelioration of CVD. It evidently becomes important to unravel the mechanisms of the association between IR and CVDs in order to formulate novel efficient drugs to treat patients suffering from insulin resistance-mediated cardiovascular diseases. The possible associations between insulin resistance and cardiovascular diseases are reviewed here. PMID:26542377

  14. 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...

  15. 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.

  16. Plasma Elevations of Tumor Necrosis Factor-Receptor-1 at Day 7 Post Allogeneic Transplant Correlate with Graft Versus Host Disease Severity and Overall Survival in Pediatric Patients

    PubMed Central

    Kitko, Carrie L.; Paczesny, Sophie; Yanik, Gregory; Braun, Thomas; Jones, Dawn; Whitfield, Joel; Choi, Sung W.; Hutchinson, Raymond J.; Ferrara, James L. M.; Levine, John E.

    2008-01-01

    Tumor necrosis factor-α (TNF-α) is known to play a role in the pathogenesis of graft-vs-host disease (GVHD), a cause of significant morbidity and treatment-related mortality (TRM) after allogeneic hematopoietic stem cell transplantation (HCT). We measured the concentration of TNF-Receptor-1 (TNFR1) in the plasma of HCT recipients as a surrogate marker for TNF-α both prior to transplant and at day 7 in 82 children who underwent a myeloablative allogeneic HCT at the University of Michigan between 2000 and 2005. GVHD grade II-IV developed in 49% of patients at a median of 20 days after HCT. Increases in TNFR1 level at day 7 post HCT, expressed as ratios compared to pre-transplant baseline, correlated with severity of GVHD (p=0.02). In addition, day 7 TNFR1 ratios > 2.5 baseline were associated with inferior 1 year overall survival (51% vs 74%, p=0.04). As an individual biomarker, TNFR1 lacks sufficient precision to be used as a predictor for the development of GVHD. However, increases in the concentration of TNFR1, which are detectable up to two weeks in advance of clinical manifestations of GVHD, correlate with survival in pediatric HCT patients. PMID:18541194

  17. The case of a city where 1 in 6 residents is a refugee: ecological factors and host community adaptation in successful resettlement.

    PubMed

    Smith, R Scott

    2008-12-01

    The notable success of an upstate New York community in resettling refugees raises the question of whether multiple waves of resettlement over a 15-year period have resulted in greater accommodation to refugees. Structured interviews based on transactional models of acculturation were used along with archival data to explore ecological factors supporting a host community's behavioral flexibility and perseverance in response to the influx of refugees. Evidence suggests that socioeconomic climate, historical background/social norms, and the organizational structure of agencies involved in resettlement moderate successful inclusion of refugees into a host community in a bidirectional process.

  18. Enterovirus-induced miR-141 contributes to shutoff of host protein translation by targeting the translation initiation factor eIF4E.

    PubMed

    Ho, Bing-Ching; Yu, Sung-Liang; Chen, Jeremy J W; Chang, Sui-Yuan; Yan, Bo-Shiun; Hong, Qi-Sheng; Singh, Sher; Kao, Chuan-Liang; Chen, Hsuan-Yu; Su, Kang-Yi; Li, Ker-Chau; Cheng, Chiou-Ling; Cheng, Hao-Wei; Lee, Jen-Yi; Lee, Chun-Nan; Yang, Pan-Chyr

    2011-01-20

    Viruses rely on the host translation machinery to complete their life cycles. Picornaviruses use an internal ribosome entry site to initiate cap-independent protein translation and in parallel host cap-dependent translation is shut off. This process is thought to occur primarily via cleavage of host translation initiation factors eIF4GI and eIF4GII by viral proteases. Here we describe another mechanism whereby miR-141 induced upon enterovirus infection targets the cap-dependent translation initiation factor, eIF4E, for shutoff of host protein synthesis. Knockdown of miR-141 reduces viral propagation, and silencing of eIF4E can completely reverse the inhibitory effect of the miR-141 antagomiR on viral propagation. Ectopic expression of miR-141 promotes the switch from cap-dependent to cap-independent translation. Moreover, we identified a transcription factor, EGR1, which is partly responsible for miR-141 induction in response to enterovirus infection. Our results suggest that upregulation of miR-141 upon enterovirus infection can facilitate viral propagation by expediting the translational switch.

  19. The ubiquitin ligase TRIM27 functions as a host restriction factor antagonized by Mycobacterium tuberculosis PtpA during mycobacterial infection

    PubMed Central

    Wang, Jing; Teng, Jade L. L.; Zhao, Dongdong; Ge, Pupu; Li, Bingxi; Woo, Patrick C. Y.; Liu, Cui Hua

    2016-01-01

    Macrophage-mediated innate immune responses play crucial roles in host defense against pathogens. Recent years have seen an explosion of host proteins that act as restriction factors blocking viral replication in infected cells. However, the essential factors restricting Mycobacterium tuberculosis (Mtb) and their regulatory roles during mycobacterial infection remain largely unknown. We previously reported that Mtb tyrosine phosphatase PtpA, a secreted effector protein required for intracellular survival of Mtb, inhibits innate immunity by co-opting the host ubiquitin system. Here, we identified a new PtpA-interacting host protein TRIM27, which is reported to possess a conserved RING domain and usually acts as an E3 ubiquitin ligase that interferes with various cellular processes. We further demonstrated that TRIM27 restricts survival of mycobacteria in macrophages by promoting innate immune responses and cell apoptosis. Interestingly, Mtb PtpA could antagonize TRIM27-promoted JNK/p38 MAPK pathway activation and cell apoptosis through competitively binding to the RING domain of TRIM27. TRIM27 probably works as a potential restriction factor for Mtb and its function is counteracted by Mtb effector proteins such as PtpA. Our study suggests a potential tuberculosis treatment via targeting of the TRIM27-PtpA interfaces. PMID:27698396

  20. Abiotic and biotic factors associated with tick population dynamics on a mammalian host: Ixodes hexagonus infesting otters, Lutra lutra.

    PubMed

    Sherrard-Smith, Ellie; Chadwick, Elizabeth; Cable, Joanne

    2012-01-01

    The Eurasian otter, Lutra lutra, hosts several parasites with zoonotic potential. As this semiaquatic mammal has large ranges across terrestrial, freshwater and marine habitats, it has the capacity for wide dispersion of pathogens. Despite this, parasites of otters have received relatively little attention. Here, we examine their ectoparasite load and assess whether this is influenced by abiotic or biotic variables. Climatic phenomena such as the North Atlantic Oscillation (NAO) affect weather conditions in northern Europe. Consequently parasite distributions, particularly species with life stages exposed to the external environment, can be affected. We assessed the extent to which inter-annual variations in large-scale weather patterns (specifically the NAO and Central England (CE) temperatures) and host characteristics influenced tick prevalence and intensity. Ectoparasites consisted of a single species, the nidiculous tick Ixodes hexagonus (prevalence = 24.3%; mean intensity = 7.2; range = 1-122; on n = 820 otter hosts). The prevalence, but not intensity of infestation, was associated with high CE temperatures, while both prevalence and intensity were associated with positive phases of the NAO. Such associations indicate that I. hexagonus are most abundant when weather conditions are warmer and wetter. Ticks were more prevalent on juvenile than sub-adult or adult otters, which probably reflects the length of time the hosts spend in the holt where these ticks quest. High tick number was associated with poor host condition, so either poor condition hosts are more susceptible to ticks, or tick infestations negatively impact on host condition. Otters are clearly an important and common host for I. hexagonus, which has implications for vector-borne diseases. This work is the first to consider the impacts of long-term weather patterns on I. hexagonus and uses wild-animal cadavers to illustrate the importance of abiotic and biotic pressures impacting parasitic

  1. 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

  2. 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

  3. [Identification of Host Factors Interacting with the Movement Protein of Apple Chlorotic Leaf Spot Virus by Yeast Two-Hybrid System].

    PubMed

    He, Yikun; Zhong, Min; Zhang, Yu; Wang, Yanan; Cao, Keqiang

    2015-03-01

    In order to identify host factors which interact with the movement protein (MP) of Apple chlorotic leaf spot virus (ACLSV), ACLSV MP was cloned into the bait vector pGBKT7 and used to screen a cDNA library of Malus sylvestris cv. R12740-7A, which had previously been constructed by yeast two-hybrid sequencing transformation. The protein functions of the identified host factors were determined according to their gene annotations in GenBank. The result showed that the bait plasmid pGBKT7-MP showed no virulence or self-activating effect on yeast strain Y2H Gold. Sixty-nine interactor proteins were identified, which were divided into the following 10 classes according to their described functions: hydrolases; pathogenesis-related proteins; DNA binding proteins; phosphatases; ligases; proteins with catalytic activity; phenylalanine ammonialyases; peroxidases; NAD binding proteins; and proteins of unknown function. Bioinformatic analysis of gene homology suggested that phosphatases, pathogenesis-related proteins and glyceraldehyde-3-phosphate dehydrogenase A may play an important role in the interaction between virus and host. This study may provide a theoretical basis for the further study of viral pathogenesis and virus-host interaction mechanisms.

  4. 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

  5. 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.

  6. 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

  7. 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.

  8. 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

  9. Host Protein Moloney Leukemia Virus 10 (MOV10) Acts as a Restriction Factor of Influenza A Virus by Inhibiting the Nuclear Import of the Viral Nucleoprotein

    PubMed Central

    Zhang, Junsong; Huang, Feng; Tan, Likai; Bai, Chuan; Chen, Bing; Liu, Jun; Liang, Juanran; Liu, Chao; Zhang, Shaoying; Lu, Gen; Chen, Yuan

    2016-01-01

    ABSTRACT The viral ribonucleoprotein (vRNP) complex of influenza A viruses (IAVs) contains an RNA-dependent RNA polymerase complex (RdRp) and nucleoprotein (NP) and is the functional unit for viral RNA transcription and replication. The vRNP complex is an important determinant of virus pathogenicity and host adaptation, implying that its function can be affected by host factors. In our study, we identified host protein Moloney leukemia virus 10 (MOV10) as an inhibitor of IAV replication, since depletion of MOV10 resulted in a significant increase in virus yield. MOV10 inhibited the polymerase activity in a minigenome system through RNA-mediated interaction with the NP subunit of vRNP complex. Importantly, we found that the interaction between MOV10 and NP prevented the binding of NP to importin-α, resulting in the retention of NP in the cytoplasm. Both the binding of MOV10 to NP and its inhibitory effect on polymerase activity were independent of its helicase activity. These results suggest that MOV10 acts as an anti-influenza virus factor through specifically inhibiting the nuclear transportation of NP and subsequently inhibiting the function of the vRNP complex. IMPORTANCE The interaction between the influenza virus vRNP complex and host factors is a major determinant of viral tropism and pathogenicity. Our study identified MOV10 as a novel host restriction factor for the influenza virus life cycle since it inhibited the viral growth rate. Conversely, importin-α has been shown as a determinant for influenza tropism and a positive regulator for viral polymerase activity in mammalian cells but not in avian cells. MOV10 disrupted the interaction between NP and importin-α, suggesting that MOV10 could also be an important host factor for influenza virus transmission and pathogenicity. Importantly, as an interferon (IFN)-inducible protein, MOV10 exerted a novel mechanism for IFNs to inhibit the replication of influenza viruses. Furthermore, our study potentially

  10. 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

  11. 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

  12. 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

  13. A murine host cell factor required for nicking of the dimer bridge of MVM recognizes two CG nucleotides displaced by 10 basepairs.

    PubMed

    Liu, Q; Astell, C R

    1996-10-01

    During replication of the minute virus of mice (MVM) genome, a dimer replicative form (RF) intermediate is resolved into two monomer RF molecules in such a way as to retain a unique sequence within the left hand hairpin terminus of the viral genome. Although the proposed mechanism for resolution of the dimer RF remains uncertain, it likely involves site-specific nicking of the dimer bridge. The RF contains two double-stranded copies of the viral genome joined by the extended 3' hairpin. Minor sequence asymmetries within the 3' hairpin allow the two halves of the dimer bridge to be distinguished. The A half contains the sequence [sequence: see text], whereas the B half contains the sequence [sequence: see text]. Using an in vitro assay, we show that only the B half of the MVM dimer bridge is nicked site-specifically when incubated with crude NS-1 protein (expressed in insect cells) and mouse LA9 cellular extract. When highly purified NS-1, the major nonstructural protein of MVM, is used in this nicking reaction, there is an absolute requirement for the LA9 cellular extract, suggesting a cellular factor (or factors) is (are) required. A series of mutations were created in the putative host factor binding region (HFBR) on the B half of the MVM dimer bridge adjacent to the NS-1 binding site. Nicking assays of these B half mutants showed that two CG motifs displaced by 10 nucleotides are important for nicking. Gel mobility shift assays demonstrated that a host factor(s) can bind to the HFBR of the B half of the dimer bridge and efficient binding depends on the presence of both CG motifs. Competitor DNA containing the wild-type HFBR sequence is able to specifically inhibit nicking of the B half, indicating that the host factor(s) bound to the HFBR is(are) essential for site-specific nicking to occur.

  14. 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

  15. Host Factors Influencing the Retrohoming Pathway of Group II Intron RmInt1, Which Has an Intron-Encoded Protein Naturally Devoid of Endonuclease Activity

    PubMed Central

    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

  16. Sterol Carrier Protein 2, a Critical Host Factor for Dengue Virus Infection, Alters the Cholesterol Distribution in Mosquito Aag2 Cells.

    PubMed

    Fu, Qiang; Inankur, Bahar; Yin, John; Striker, Rob; Lan, Que

    2015-09-01

    Host factors that enable dengue virus (DENV) to propagate in the mosquito host cells are unclear. It is known that cellular cholesterol plays an important role in the life cycle of DENV in human host cells but unknown if the lipid requirements differ for mosquito versus mammalian. In mosquito Aedes aegypti, sterol carrier protein 2 (SCP-2) is critical for cellular cholesterol homeostasis. In this study, we identified SCP-2 as a critical host factor for DENV production in mosquito Aag2 cells. Treatment with a small molecule commonly referred to as SCPI-1, (N-(4-{[4-(3,4-dichlorophenyl)-1,3-thiazol-2-yl]amino}phenyl)acetamide hydrobromide, a known inhibitor of SCP-2, or knockdown of SCP-2 dramatically repressed the virus production in mosquito but not mammalian cells. We showed that the intracellular cholesterol distribution in mosquito cells was altered by SCP-2 inhibitor treatment, suggesting that SCP-2-mediated cholesterol trafficking pathway is important for DENV viral production. A comparison of the effect of SCP-2 on mosquito and human cells suggests that SCPI-1 treatment decreases cholesterol in both cell lines, but this decrease in cholesterol only leads to a decline in viral titer in mosquito host cells, perhaps, owing to a more drastic effect on perinuclear cholesterol storages in mosquito cells that was absent in human cells. SCP-2 had no inhibitory effect on another enveloped RNA virus grown in mosquito cells, suggesting that SCP-2 does not have a generalized anti-cellular or antiviral effect. Our cell culture results imply that SCP-2 may play a limiting role in mosquito-dengue vector competence.

  17. 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 ...

  18. A zinc-binding citrus protein metallothionein can act as a plant defense factor by controlling host-selective ACR-toxin production.

    PubMed

    Nishimura, Satoshi; Tatano, Satoshi; Miyamoto, Yoko; Ohtani, Kouhei; Fukumoto, Takeshi; Gomi, Kenji; Tada, Yasuomi; Ichimura, Kazuya; Akimitsu, Kazuya

    2013-01-01

    Metallothionein is a small cysteine-rich protein known to have a metal-binding function. We isolated three different lengths of rough lemon cDNAs encoding a metallothionein (RlemMT1, RlemMT2 and RlemMT3), and only RlemMT1-recombinant protein had zinc-binding activity. Appropriate concentration of zinc is an essential micronutrient for living organisms, while excess zinc is toxic. Zinc also stimulates the production of host-selective ACR-toxin for citrus leaf spot pathogen of Alternaria alternata rough lemon pathotype. Trapping of zinc by RlemMT1-recombinant protein or by a zinc-scavenging agent in the culture medium caused suppression of ACR-toxin production by the fungus. Since ACR-toxin is the disease determinant for A. alternata rough lemon pathotype, addition of RlemMT1 to the inoculum suspension led to a significant decrease in symptoms on rough lemon leaves as a result of reduced ACR-toxin production from the zinc trap around infection sites. RlemMT1-overexpression mutant of A. alternata rough lemon pathotype also produced less ACR-toxin and reduced virulence on rough lemon. This suppression was caused by an interruption of zinc absorption by cells from the trapping of the mineral by RlemMT1 and an excess supplement of ZnSO(4) restored toxin production and pathogenicity. Based on these results, we propose that zinc adsorbents including metallothionein likely can act as a plant defense factor by controlling toxin biosynthesis via inhibition of zinc absorption by the pathogen.

  19. The Yersinia Virulence Factor YopM Hijacks Host Kinases to Inhibit Type III Effector-Triggered Activation of the Pyrin Inflammasome.

    PubMed

    Chung, Lawton K; Park, Yong Hwan; Zheng, Yueting; Brodsky, Igor E; Hearing, Patrick; Kastner, Daniel L; Chae, Jae Jin; Bliska, James B

    2016-09-14

    Pathogenic Yersinia, including Y. pestis, the agent of plague in humans, and Y. pseudotuberculosis, the related enteric pathogen, deliver virulence effectors into host cells via a prototypical type III secretion system to promote pathogenesis. These effectors, termed Yersinia outer proteins (Yops), modulate multiple host signaling responses. Studies in Y. pestis and Y. pseudotuberculosis have shown that YopM suppresses infection-induced inflammasome activation; however, the underlying molecular mechanism is largely unknown. Here we show that YopM specifically restricts the pyrin inflammasome, which is triggered by the RhoA-inactivating enzymatic activities of YopE and YopT, in Y. pseudotuberculosis-infected macrophages. The attenuation of a yopM mutant is fully reversed in pyrin knockout mice, demonstrating that YopM inhibits pyrin to promote virulence. Mechanistically, YopM recruits and activates the host kinases PRK1 and PRK2 to negatively regulate pyrin by phosphorylation. These results show how a virulence factor can hijack host kinases to inhibit effector-triggered pyrin inflammasome activation. PMID:27569559

  20. 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

  1. Low edge safety factor operation and passive disruption avoidance in current carrying plasmas by the addition of stellarator rotational transform

    NASA Astrophysics Data System (ADS)

    Pandya, M. D.; ArchMiller, M. C.; Cianciosa, M. R.; Ennis, D. A.; Hanson, J. D.; Hartwell, G. J.; Hebert, J. D.; Herfindal, J. L.; Knowlton, S. F.; Ma, X.; Massidda, S.; Maurer, D. A.; Roberds, N. A.; Traverso, P. J.

    2015-11-01

    Low edge safety factor operation at a value less than two ( q (a )=1 /ι̷tot(a )<2 ) is routine on the Compact Toroidal Hybrid device with the addition of sufficient external rotational transform. Presently, the operational space of this current carrying stellarator extends down to q (a )=1.2 without significant n = 1 kink mode activity after the initial plasma current rise phase of the discharge. The disruption dynamics of these low edge safety factor plasmas depend upon the fraction of helical field rotational transform from external stellarator coils to that generated by the plasma current. We observe that with approximately 10% of the total rotational transform supplied by the stellarator coils, low edge q disruptions are passively suppressed and avoided even though q(a) < 2. When the plasma does disrupt, the instability precursors measured and implicated as the cause are internal tearing modes with poloidal, m, and toroidal, n, helical mode numbers of m /n =3 /2 and 4/3 observed on external magnetic sensors and m /n =1 /1 activity observed on core soft x-ray emissivity measurements. Even though the edge safety factor passes through and becomes much less than q(a) < 2, external n = 1 kink mode activity does not appear to play a significant role in the disruption phenomenology observed.

  2. 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

    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

    2013-12-01

    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

  3. 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

  4. Quantitative Proteomic Analysis of Host-virus Interactions Reveals a Role for Golgi Brefeldin A Resistance Factor 1 (GBF1) in Dengue Infection*

    PubMed Central

    Carpp, Lindsay N.; Rogers, Richard S.; Moritz, Robert L.; Aitchison, John D.

    2014-01-01

    Dengue virus is considered to be the most important mosquito-borne virus worldwide and poses formidable economic and health care burdens on many tropical and subtropical countries. Dengue infection induces drastic rearrangement of host endoplasmic reticulum membranes into complex membranous structures housing replication complexes; the contribution(s) of host proteins and pathways to this process is poorly understood but is likely to be mediated by protein-protein interactions. We have developed an approach for obtaining high confidence protein-protein interaction data by employing affinity tags and quantitative proteomics, in the context of viral infection, followed by robust statistical analysis. Using this approach, we identified high confidence interactors of NS5, the viral polymerase, and NS3, the helicase/protease. Quantitative proteomics allowed us to exclude a large number of presumably nonspecific interactors from our data sets and imparted a high level of confidence to our resulting data sets. We identified 53 host proteins reproducibly associated with NS5 and 41 with NS3, with 13 of these candidates present in both data sets. The host factors identified have diverse functions, including retrograde Golgi-to-endoplasmic reticulum transport, biosynthesis of long-chain fatty-acyl-coenzyme As, and in the unfolded protein response. We selected GBF1, a guanine nucleotide exchange factor responsible for ARF activation, from the NS5 data set for follow up and functional validation. We show that GBF1 plays a critical role early in dengue infection that is independent of its role in the maintenance of Golgi structure. Importantly, the approach described here can be applied to virtually any organism/system as a tool for better understanding its molecular interactions. PMID:24855065

  5. Global repression of host-associated genes of the Lyme disease spirochete through post-transcriptional modulation of the alternative sigma factor RpoS.

    PubMed

    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.

  6. The Staphylococcus aureus Protein Sbi Acts as a Complement Inhibitor and Forms a Tripartite Complex with Host Complement Factor H and C3b

    PubMed Central

    van den Elsen, Jean; Burman, Julia; Hälbich, Steffi; Richter, Julia; Skerka, Christine; Zipfel, Peter F.

    2008-01-01

    The Gram-positive bacterium Staphylococcus aureus, similar to other pathogens, binds human complement regulators Factor H and Factor H related protein 1 (FHR-1) from human serum. Here we identify the secreted protein Sbi (Staphylococcus aureus binder of IgG) as a ligand that interacts with Factor H by a—to our knowledge—new type of interaction. Factor H binds to Sbi in combination with C3b or C3d, and forms tripartite Sbi∶C3∶Factor H complexes. Apparently, the type of C3 influences the stability of the complex; surface plasmon resonance studies revealed a higher stability of C3d complexed to Sbi, as compared to C3b or C3. As part of this tripartite complex, Factor H is functionally active and displays complement regulatory activity. Sbi, by recruiting Factor H and C3b, acts as a potent complement inhibitor, and inhibits alternative pathway-mediated lyses of rabbit erythrocytes by human serum and sera of other species. Thus, Sbi is a multifunctional bacterial protein, which binds host complement components Factor H and C3 as well as IgG and β2-glycoprotein I and interferes with innate immune recognition. PMID:19112495

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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.

  13. 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

  14. Soluble tumour necrosis factor (TNF)-receptor levels in serum as markers of anti-viral host reactivity

    PubMed Central

    Bartholdy, C; Nansen, A; Marker, O; Thomsen, A R

    1999-01-01

    The role of soluble receptors for TNF-α (sTNF-Rs) as markers of virus-induced host responses was studied by the use of murine model infections. A marked elevation in serum levels of sTNF-R75, but not sTNF-R55, was found 1 day after infection with vesicular stomatitis virus (VSV). In mice infected with lymphocytic choriomeningitis virus (LCMV), an early increase was also revealed, but peak levels of sTNF-R75 were observed later temporally related to maximal T cell-mediated anti-viral activity. Analysing different well characterized knockout mice, it was found that elevated release of sTNF-R75 into serum early after VSV infection was independent of T cells, whereas interferon (IFN)-α/β seemed to be a major mediator. In contrast, increased release of sTNF-R75 into serum 8 days post-LCMV infection was mediated via T cells but independently of both CD40 ligand and IFN-γ. A simple correlation between release of sTNF-Rs in vivo and macrophage activation in vitro was not present. These findings indicate that sTNF-R75 is indeed a sensitive marker of both innate and specific cell-mediated host reactivity during viral infection, but it is not correlated to a single immunological parameter. PMID:10337022

  15. 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

  16. 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

  17. A host-factor interaction and localization map for a plant-adapted rhabdovirus implicates cytoplasm-tethered transcription activators in cell-to-cell movement.

    PubMed

    Min, Byoung-Eun; Martin, Kathleen; Wang, Renyuan; Tafelmeyer, Petra; Bridges, Max; Goodin, Michael

    2010-11-01

    To identify host factors that play critical roles in processes, including cell-to-cell movement of plant-adapted rhabdoviruses, we constructed and validated a high-resolution Nicotiana benthamiana yeast two-hybrid library. The library was screened with the putative movement protein (sc4), nucleocapsid (N), and matrix (M) proteins of Sonchus yellow net virus (SYNV). This resulted in identification of 31 potential host factors. Steady-state localization studies using autofluorescent protein fusions to full-length clones of interactors were conducted in transgenic N. benthamiana marker lines. Bimolecular fluorescence complementation assays were used to validate two-hybrid interactions. The sc4 interactor, sc4i21, localized to microtubules. The N interactor, Ni67, localized to punctuate loci on the endoplasmic reticulum. These two proteins are 84% identical homologues of the Arabidopsis phloem-associated transcription activator AtVOZ1, and contain functional nuclear localization signals. Sc4i17 is a microtubule-associated motor protein. The M interactor, Mi7, is a nuclear-localized transcription factor. Combined with a binary interaction map for SYNV proteins, our data support a model in which the SYNV nucleocapsids are exported from the nucleus and moved cell-to-cell by transcription activators tethered in the cytoplasm.

  18. 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

  19. 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.

  20. Additional cytosine inside mitochondrial C-tract D-loop as a progression risk factor in oral precancer cases

    PubMed Central

    Pandey, Rahul; Mehrotra, Divya; Mahdi, Abbas Ali; Sarin, Rajiv; Kowtal, Pradnya

    2014-01-01

    Introduction Alterations inside Polycytosine tract (C-tract) of mitochondrial DNA (mtDNA) have been described in many different tumor types. The Poly-Cytosine region is located within the mtDNA D-loop region which acts as point of mitochondrial replication origin. A suggested pathogenesis is that it interferes with the replication process of mtDNA which in turn affects the mitochondrial functioning and generates disease. Methodology 100 premalignant cases (50 leukoplakia & 50 oral submucous fibrosis) were selected and the mitochondrial DNA were isolated from the lesion tissues and from the blood samples. Polycytosine tract in mtDNA was sequenced by direct capillary sequencing. Results 40 (25 leukoplakia & 15 oral submucous fibrosis) patients harbored lesions that displayed one additional cytosine after nucleotide thymidine (7CT6C) at nt position 316 in C-tract of mtDNA which were absent in corresponding mtDNA derived from blood samples. Conclusion Our results show an additional cytosine in the mtDNA at polycytosine site in oral precancer cases. It is postulated that any increase/decrease in the number of cytosine residues in the Poly-Cytosine region may affect the rate of mtDNA replication by impairing the binding of polymerase and other transacting factors. By promoting mitochondrial genomic instability, it may have a central role in the dysregulation of mtDNA functioning, for example alterations in energy metabolism that may promote tumor development. We, therefore, report and propose that this alteration may represent the early development of oral cancer. Further studies with large number of samples are needed in to confirm the role of such mutation in carcinogenesis. PMID:25737911

  1. 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.

  2. 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

  3. 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

  4. 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

  5. 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

  6. Effects of Factor XIII Deficiency on Thromboelastography. Thromboelastography with Calcium and Streptokinase Addition is more Sensitive than Solubility Tests

    PubMed Central

    Martinuzzo, M.; Barrera, L.; Altuna, D.; Baña, F. Tisi; Bieti, J.; Amigo, Q.; D’Adamo, M.; López, M.S.; Oyhamburu, J.; Otaso, J.C.

    2016-01-01

    Background Homozygous or double heterozygous factor XIII (FXIII) deficiency is characterized by soft tissue hematomas, intracranial and delayed spontaneous bleeding. Alterations of thromboelastography (TEG) parameters in these patients have been reported. The aim of the study was to show results of TEG, TEG Lysis (Lys 60) induced by subthreshold concentrations of streptokinase (SK), and to compare them to the clot solubility studies results in samples of a 1-year-old girl with homozygous or double heterozygous FXIII deficiency. Case A year one girl with a history of bleeding from the umbilical cord. During her first year of life, several hematomas appeared in soft upper limb tissue after punctures for vaccination and a gluteal hematoma. One additional sample of a heterozygous patient and three samples of acquired FXIII deficiency were also evaluated. Materials and Methods Clotting tests, von Willebrand factor (vWF) antigen and activity, plasma FXIII-A subunit (pFXIII-A) were measured by an immunoturbidimetric assay in a photo-optical coagulometer. Solubility tests were performed with Ca2+-5 M urea and thrombin-2% acetic acid. Basal and post-FXIII concentrate infusion samples were studied. TEG was performed with CaCl2 or CaCl2 + SK (3.2 U/mL) in a Thromboelastograph. Results Prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time, fibrinogen, factor VIIIc, vWF, and platelet aggregation were normal. Antigenic pFXIII-A subunit was < 2%. TEG, evaluated at diagnosis and post FXIII concentrate infusion (pFXIII-A= 37%), presented a normal reaction time (R), 8 min, prolonged k (14 and 11min respectively), a low Maximum-Amplitude (MA) ( 39 and 52 mm respectively), and Clot Lysis (Lys60) slightly increased (23 and 30% respectively). In the sample at diagnosis, clot solubility was abnormal, 50 and 45 min with Ca-Urea and thrombin-acetic acid, respectively, but normal (>16 hours) 1-day post-FXIII infusion. Analysis of FXIII deficient and normal

  7. Effects of Factor XIII Deficiency on Thromboelastography. Thromboelastography with Calcium and Streptokinase Addition is more Sensitive than Solubility Tests

    PubMed Central

    Martinuzzo, M.; Barrera, L.; Altuna, D.; Baña, F. Tisi; Bieti, J.; Amigo, Q.; D’Adamo, M.; López, M.S.; Oyhamburu, J.; Otaso, J.C.

    2016-01-01

    Background Homozygous or double heterozygous factor XIII (FXIII) deficiency is characterized by soft tissue hematomas, intracranial and delayed spontaneous bleeding. Alterations of thromboelastography (TEG) parameters in these patients have been reported. The aim of the study was to show results of TEG, TEG Lysis (Lys 60) induced by subthreshold concentrations of streptokinase (SK), and to compare them to the clot solubility studies results in samples of a 1-year-old girl with homozygous or double heterozygous FXIII deficiency. Case A year one girl with a history of bleeding from the umbilical cord. During her first year of life, several hematomas appeared in soft upper limb tissue after punctures for vaccination and a gluteal hematoma. One additional sample of a heterozygous patient and three samples of acquired FXIII deficiency were also evaluated. Materials and Methods Clotting tests, von Willebrand factor (vWF) antigen and activity, plasma FXIII-A subunit (pFXIII-A) were measured by an immunoturbidimetric assay in a photo-optical coagulometer. Solubility tests were performed with Ca2+-5 M urea and thrombin-2% acetic acid. Basal and post-FXIII concentrate infusion samples were studied. TEG was performed with CaCl2 or CaCl2 + SK (3.2 U/mL) in a Thromboelastograph. Results Prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time, fibrinogen, factor VIIIc, vWF, and platelet aggregation were normal. Antigenic pFXIII-A subunit was < 2%. TEG, evaluated at diagnosis and post FXIII concentrate infusion (pFXIII-A= 37%), presented a normal reaction time (R), 8 min, prolonged k (14 and 11min respectively), a low Maximum-Amplitude (MA) ( 39 and 52 mm respectively), and Clot Lysis (Lys60) slightly increased (23 and 30% respectively). In the sample at diagnosis, clot solubility was abnormal, 50 and 45 min with Ca-Urea and thrombin-acetic acid, respectively, but normal (>16 hours) 1-day post-FXIII infusion. Analysis of FXIII deficient and normal

  8. Host Phylogeny Determines Viral Persistence and Replication in Novel Hosts

    PubMed Central

    Longdon, Ben; Hadfield, Jarrod D.; Webster, Claire L.

    2011-01-01

    Pathogens switching to new hosts can result in the emergence of new infectious diseases, and determining which species are likely to be sources of such host shifts is essential to understanding disease threats to both humans and wildlife. However, the factors that determine whether a pathogen can infect a novel host are poorly understood. We have examined the ability of three host-specific RNA-viruses (Drosophila sigma viruses from the family Rhabdoviridae) to persist and replicate in 51 different species of Drosophilidae. Using a novel analytical approach we found that the host phylogeny could explain most of the variation in viral replication and persistence between different host species. This effect is partly driven by viruses reaching a higher titre in those novel hosts most closely related to the original host. However, there is also a strong effect of host phylogeny that is independent of the distance from the original host, with viral titres being similar in groups of related hosts. Most of this effect could be explained by variation in general susceptibility to all three sigma viruses, as there is a strong phylogenetic correlation in the titres of the three viruses. These results suggest that the source of new emerging diseases may often be predictable from the host phylogeny, but that the effect may be more complex than simply causing most host shifts to occur between closely related hosts. PMID:21966271

  9. 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

  10. 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

  11. The benefit of additional oviposition targets for a polyphagous butterfly.

    PubMed

    Johansson, Josefin; Bergström, Anders; Janz, Niklas

    2007-01-01

    While the reasons for the prevalence of specialists over generalists among herbivorous insects have been at the focus of much interest, less effort has been put into understanding the polyphagous exceptions. Recent studies have suggested that these exceptions may be important for insect diversification, which calls for a better understanding of the potential factors that can lead to an increased host plant repertoire. Females of the Nymphalid butterfly, Polygonia c-album, were used to test if egg output and/or likelihood of finding a host increased with the addition of a secondary host. There was no effect of prior eggs on the host for willingness to oviposit on a plant. The main experiments were conducted both in small laboratory cages and in large outdoor experimental arenas. No positive effect was found when another oviposition target was added in small cages in the laboratory. On the other hand, in the outdoor arenas the females more often found a host to oviposit on and had a higher egg output when they had access to an additional host, even though the second host was lower in their preference hierarchy. The difference between these experiments was attributed to searching for acceptable host plants within a patch, a factor that was included in the large cages but not in the small. When host availability is limited, adding oviposition targets can potentially act to counterbalance specialization and thus favor the evolution of generalization.

  12. The Role of Host Factors and Bacterial Virulence Genes in the Development of Pyelonephritis Caused by Escherichia coli in Renal Transplant Recipients

    PubMed Central

    Siliano, Priscila Reina; Rocha, Lillian Andrade; Osmar Medina-Pestana, José

    2010-01-01

    Background and objectives: The aim of this study was to determine the role of host factors and bacterial virulence genes in the development of pyelonephritis caused by Escherichia coli in renal transplant (Tx) recipients. Design, setting, participants, & measurements: A total of 328 E. coli isolates from cases of cystitis (Cys; n = 239) or pyelonephritis (PN; n = 89), with 169 from renal Tx recipients, were subjected to molecular analyses to identify P-fimbria subunits (PapC, PapG II, and PapGIII), G- and M-fimbriae, and aerobactin. The presence of antibiotic resistance was also determined. Parameters such as gender, age, immunosuppression regimens, causes of ESRD, kidney donor, intraoperative anastomosis, use of double J stent, trimethoprim/sulfamethoxazole (TMP/SMZ) prophylaxis, and time after Tx were evaluated. Results: A multivariate analysis showed a significant association between PN and renal Tx. In renal Tx recipients, the risk of occurrence of PN was significantly higher among males and for those no longer receiving TMP/SMZ prophylaxis. E. coli strains isolated from PN presented a lower prevalence of papGIII and lower rates of resistance to pipemidic acid. Although papGII was more prevalent in PN than in Cys, it was not independently associated with PN. Conclusions: These findings suggested that renal Tx increases the risk for PN, and the male sex represented a host factor independently associated with risk, whereas the prophylaxis with TMP/SMZ was protective. The lack of papGIII and low resistance to first-generation quinolones were bacterial-independent risk factors for PN in Tx. PMID:20448070

  13. Yip1A, a novel host factor for the activation of the IRE1 pathway of the unfolded protein response during Brucella infection.

    PubMed

    Taguchi, Yuki; Imaoka, Koichi; Kataoka, Michiyo; Uda, Akihiko; Nakatsu, Daiki; Horii-Okazaki, Sakuya; Kunishige, Rina; Kano, Fumi; Murata, Masayuki

    2015-03-01

    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

  14. 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

  15. 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

  16. Construction and analysis of regulatory genetic networks in cervical cancer based on involved microRNAs, target genes, transcription factors and host genes.

    PubMed

    Wang, Ning; Xu, Zhiwen; Wang, Kunhao; Zhu, Minghui; Li, Yang

    2014-04-01

    Over recent years, genes and microRNA (miRNA/miR) have been considered as key biological factors in human carcinogenesis. During cancer development, genes may act as multiple identities, including target genes of miRNA, transcription factors and host genes. The present study concentrated on the regulatory networks consisting of the biological factors involved in cervical cancer in order to investigate their features and affect on this specific pathology. Numerous raw data was collected and organized into purposeful structures, and adaptive procedures were defined for application to the prepared data. The networks were therefore built with the factors as basic components according to their interacting associations. The networks were constructed at three levels of interdependency, including a differentially-expressed network, a related network and a global network. Comparisons and analyses were made at a systematic level rather than from an isolated gene or miRNA. Critical hubs were extracted in the core networks and notable features were discussed, including self-adaption feedback regulation. The present study expounds the pathogenesis from a novel point of view and is proposed to provide inspiration for further investigation and therapy.

  17. Spatial and temporal structuring of arbuscular mycorrhizal communities is differentially influenced by abiotic factors and host crop in a semi-arid prairie agroecosystem.

    PubMed

    Bainard, Luke D; Bainard, Jillian D; Hamel, Chantal; Gan, Yantai

    2014-05-01

    Agroecosystems are dynamic systems that experience frequent chemical inputs and changes in plant cover. The objective of this study was to test whether abiotic (soil chemical properties and climate) and biotic (plant host identity) factors influence the spatial and temporal structuring of arbuscular mycorrhizal fungal (AMF) communities in a semi-arid prairie agroecosystem. 454 GS FLX+ high-throughput sequencing technology was successfully utilized to characterize the AMF communities based on long reads (mean length: 751.7 bp) and generated high-resolution data with excellent taxonomic coverage. The composition of the AMF community colonizing roots of the three crops (pea, lentil, and wheat) significantly differed, but plant host identity had a minimal effect on the composition of the AMF community in the soil. We observed a temporal shift in the composition of AMF communities in the roots and surrounding soil of the crops during the growing season. This temporal shift was particularly evident in the root-associated AMF community and was correlated with soil phosphate flux and climatic variables. In contrast, the spatial structuring of the AMF community in the site was correlated with soil pH and electrical conductivity. Individual AMF taxa were significantly correlated with pH, electrical conductivity, and phosphate flux, and these relationships were phylogenetically conserved at the genus level within the Glomeromycota.

  18. Differential effects of abiotic factors and host plant traits on diversity and community composition of root-colonizing arbuscular mycorrhizal fungi in a salt-stressed ecosystem.

    PubMed

    Guo, Xiaohong; Gong, Jun

    2014-02-01

    Arbuscular mycorrhizal fungi (AMF) were investigated in roots of 18 host plant species in a salinized south coastal plain of Laizhou Bay, China. From 18 clone libraries of 18S rRNA genes, all of the 22 AMF phylotypes were identified into Glomus, of which 18 and 4 were classified in group A and B in the phylogenetic tree, respectively. The phylotypes related to morphologically defined Glomus species occurred generally in soil with higher salinity. AMF phylotype richness, Shannon index, and evenness were not significantly different between root samples from halophytes vs. non-halophytes, invades vs. natives, or annuals vs. perennials. However, AMF diversity estimates frequently differed along the saline gradient or among locations, but not among pH gradients. Moreover, UniFrac tests showed that both plant traits (salt tolerance, life style or origin) and abiotic factors (salinity, pH, or location) significantly affected the community composition of AMF colonizers. Redundancy and variation partitioning analyses revealed that soil salinity and pH, which respectively explained 6.9 and 4.2 % of the variation, were the most influential abiotic variables in shaping the AMF community structure. The presented data indicate that salt tolerance, life style, and origin traits of host species may not significantly affect the AMF diversity in roots, but do influence the community composition in this salinized ecosystem. The findings also highlight the importance of soil salinity and pH in driving the distribution of AMF in plant and soil systems.

  19. Mexican American First-Generation Students' Perceptions of Siblings and Additional Factors Influencing Their College Choice Process

    ERIC Educational Resources Information Center

    Elias McAllister, Dora

    2012-01-01

    The purpose of this study was to understand the factors influencing the college choice process of Mexican American first-generation students who had an older sibling with college experience. While a considerable amount of research exists on factors influencing the college choice process of first-generation college students, and a few studies…

  20. 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

  1. 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

  2. Multiple viral mutations rather than host factors cause defective measles virus gene expression in a subacute sclerosing panencephalitis cell line.

    PubMed Central

    Cattaneo, R; Schmid, A; Billeter, M A; Sheppard, R D; Udem, S A

    1988-01-01

    A measles virus (MV) genome originally derived from brain cells of a subacute sclerosing panencephalitis patient expressed in IP-3-Ca cells an unstable MV matrix protein and was unable to produce virus particles. Transfection of this MV genome into other cell lines did not relieve these defects, showing that they are ultimately encoded by viral mutations. However, these defects were partially relieved in a weakly infectious virus which emerged from IP-3-Ca cells and which produced a matrix protein of intermediate stability. The sequences of several cDNAs related to the unstable and intermediately stable matrix proteins showed many differences in comparison with a stable matrix protein sequence and even appreciable heterogeneity among themselves. Nevertheless, partial restoration of matrix protein stability could be ascribed to a single additional amino acid change. From an examination of additional genes, we estimated that, on average, each MV genome in IP-3-Ca cells differs from the others in 30 to 40 of its 16,000 bases. The role of extreme variability of RNA virus genomes in persistent viral infections is discussed in the context of the pathogenesis of subacute sclerosing panencephalitis and of other human diseases of suspected viral etiology. Images PMID:3346948

  3. Comparing mechanisms of host manipulation across host and parasite taxa.

    PubMed

    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.

  4. 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.

  5. 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

  6. Impact of trap architecture, adjacent habitats, abiotic factors, and host plant phenology on captures of plum curculio (Coleoptera: Curculionidae) adults.

    PubMed

    Lafleur, Gérald; Chouinard, Gérald; Vincent, Charles; Cormier, Daniel

    2007-06-01

    Pyramid traps, 2.44 m and 3.66 m in height, were compared with standard-sized pyramid traps, 1.22 m in height, to assess the impact of trap architecture on captures of adult plum curculio, Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae), in two apple (Malus spp.) orchards and a blueberry (Vaccinium spp.) planting. The effects of adjacent habitat (organic orchard versus wooded areas), abiotic factors, and phenological stages of apple also were assessed to determine whether these variables influenced trap captures. Standard-sized pyramidal traps captured significantly more adults than larger trap variants. In the apple orchards, most adults (70-80%) were captured before petal fall with the exception of blocks adjacent to the organic orchard (25%). Significantly more adults were captured along the edge of an apple orchard (managed using an integrated pest management strategy) facing an organic apple orchard (76%) than along the edge facing wooded areas (24%). There was a significant positive correlation between daily trap captures and mean daily temperatures before petal fall in apple orchards.

  7. Viral and host factors associated with the HIV-1 viral load setpoint in adults from Mbeya Region, Tanzania

    PubMed Central

    Saathoff, Elmar; Pritsch, Michael; Geldmacher, Christof; Koehler, Rebecca N.; Maboko, Leonard; Maganga, Lucas; Geis, Steffen; McCutchan, Francine E.; Kijak, Gustavo H.; Kim, Jerome H.; Arroyo, Miguel A.; Gerhardt, Martina; Tovanabutra, Sodsai; Robb, Merlin L.; Williamson, Carolyn; Michael, Nelson L.; Hoelscher, Michael

    2010-01-01

    Background The viral load setpoint (VLS) is an important predictor of HIV disease progression, but there is a lack of information regarding the VLS and its possible determinants in African populations. Methods Initially HIV negative adults from three distinct groups (female barworkers, females and males from the general population) were followed for up to four years. The VLS was calculated for 108 seroconverters and associations of the VLS with possible risk factors were analyzed using univariate and multivariate regression. Results The median VLS for female barworkers, females and males from the general population were 69,850, 28,600 and 158,000 RNA copies/ml respectively. Significant associations with an elevated viral load were observed for male gender (Risk Ratio (RR)=1.83, 95% confidence interval (95%CI)=1.14–2.93), the expression of harmful HLA I alleles (RR=1.73, 95%CI=1.13–2.66) and multiple infection with different HIV-1 subtypes (RR=1.65, 95%CI =1.03–2.66). Barworkers were considerably more often infected with different HIV-1 subtypes than participants from the general population. Conclusions Our study confirms that gender and the expression of different HLA class I alleles are important determinants of the viremia at VLS and it also corroborates an earlier finding that multiple infection with different HIV-1 subtypes is associated with a higher VLS. PMID:20632457

  8. 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

  9. 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.

  10. Acquisition of natural humoral immunity to P. falciparum in early life in Benin: impact of clinical, environmental and host factors

    PubMed Central

    Dechavanne, Célia; Sadissou, Ibrahim; Bouraima, Aziz; Ahouangninou, Claude; Amoussa, Roukiyath; Milet, Jacqueline; Moutairou, Kabirou; Massougbodji, Achille; Theisen, Michael; Remarque, Edmond J.; Courtin, David; Nuel, Gregory; Migot-Nabias, Florence; Garcia, André

    2016-01-01

    To our knowledge, effects of age, placental malaria infection, infections during follow-up, nutritional habits, sickle-cell trait and individual exposure to Anopheles bites were never explored together in a study focusing on the acquisition of malaria antibody responses among infants living in endemic areas.Five hundred and sixty-seven Beninese infants were weekly followed-up from birth to 18 months of age. Immunoglobulin G (IgG), IgG1 and IgG3 specific for 5 malaria antigens were measured every 3 months. A linear mixed model was used to analyze the effect of each variable on the acquisition of antimalarial antibodies in 6-to18-month old infants in univariate and multivariate analyses. Placental malaria, nutrition intakes and sickle-cell trait did not influence the infant antibody levels to P. falciparum antigens. In contrary, age, malaria antibody levels at birth, previous and present malaria infections as well as exposure to Anopheles bites were significantly associated with the natural acquisition of malaria antibodies in 6-to18-month old Beninese infants. This study highlighted inescapable factors to consider simultaneously in an immuno-epidemiological study or a vaccine trial in early life. PMID:27670685

  11. 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

  12. Coxiella subversion of intracellular host signaling.

    PubMed

    Hussain, S Kauser; Voth, Daniel E

    2012-01-01

    Coxiella burnetii is a highly infectious bacterial pathogen that replicates in a specialized vacuole inside eukaryotic cells. Due to a prolonged growth cycle, Coxiella continuously manipulates cellular processes to generate this parasitophorous vacuole (PV) and promote host cell viability. Here, we discuss recent findings that indicate Coxiella modulates several host signaling pathways to influence survival and ensure intracellular replication. The pathogen actively inhibits apoptotic cell death and activates the pro-survival kinases Akt and Erk1/2 to promote host viability. Coxiella's anti-apoptotic activity also involves the interface between autophagy and apoptosis, which is regulated by the interaction of autophagy-related Beclin-1 and anti-apoptotic Bcl-2. Additionally, Coxiella requires host kinase activity for PV biogenesis and maintenance. Thus, signaling modulation by Coxiella is critical for multiple aspects of host cell parasitism. Collectively, recent signaling studies have enhanced our understanding of the unique Coxiella-host cell interaction. Identification of bacterial factors that regulate signaling events will further our ability to model this intriguing infectious process.

  13. 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...

  14. 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

  15. 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.

  16. Silencing of the host factor eIF(iso)4E gene confers plum pox virus resistance in plum.

    PubMed

    Wang, Xinhua; Kohalmi, Susanne E; Svircev, Antonet; Wang, Aiming; Sanfaçon, Hélène; Tian, Lining

    2013-01-01

    Plum pox virus (PPV) causes the most economically-devastating viral disease in Prunus species. Unfortunately, few natural resistance genes are available for the control of PPV. Recessive resistance to some potyviruses is associated with mutations of eukaryotic translation initiation factor 4E (eIF4E) or its isoform eIF(iso)4E. In this study, we used an RNA silencing approach to manipulate the expression of eIF4E and eIF(iso)4E towards the development of PPV resistance in Prunus species. The eIF4E and eIF(iso)4E genes were cloned from plum (Prunus domestica L.). The sequence identity between plum eIF4E and eIF(iso)4E coding sequences is 60.4% at the nucleotide level and 52.1% at the amino acid level. Quantitative real-time RT-PCR analysis showed that these two genes have a similar expression pattern in different tissues. Transgenes allowing the production of hairpin RNAs of plum eIF4E or eIF(iso)4E were introduced into plum via Agrobacterium-mediated transformation. Gene expression analysis confirmed specific reduced expression of eIF4E or eIF(iso)4E in the transgenic lines and this was associated with the accumulation of siRNAs. Transgenic plants were challenged with PPV-D strain and resistance was evaluated by measuring the concentration of viral RNA. Eighty-two percent of the eIF(iso)4E silenced transgenic plants were resistant to PPV, while eIF4E silenced transgenic plants did not show PPV resistance. Physical interaction between PPV-VPg and plum eIF(iso)4E was confirmed. In contrast, no PPV-VPg/eIF4E interaction was observed. These results indicate that eIF(iso)4E is involved in PPV infection in plum, and that silencing of eIF(iso)4E expression can lead to PPV resistance in Prunus species.

  17. 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%.

  18. 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

  19. Fusion of Legionella pneumophila outer membrane vesicles with eukaryotic membrane systems is a mechanism to deliver pathogen factors to host cell membranes.

    PubMed

    Jäger, Jens; Keese, Susanne; Roessle, Manfred; Steinert, Michael; Schromm, Andra B

    2015-05-01

    The formation and release of outer membrane vesicles (OMVs) is a phenomenon observed in many bacteria, including Legionella pneumophila. During infection, this human pathogen primarily invades alveolar macrophages and replicates within a unique membrane-bound compartment termed Legionella-containing vacuole. In the current study, we analysed the membrane architecture of L. pneumophila OMVs by small-angle X-ray scattering and biophysically characterized OMV membranes. We investigated the interaction of L. pneumophila OMVs with model membranes by Förster resonance energy transfer and Fourier transform infrared spectroscopy. These experiments demonstrated the incorporation of OMV membrane material into liposomes composed of different eukaryotic phospholipids, revealing an endogenous property of OMVs to fuse with eukaryotic membranes. Cellular co-incubation experiments showed a dose- and time-dependent binding of fluorophore-labelled OMVs to macrophages. Trypan blue quenching experiments disclosed a rapid internalization of OMVs into macrophages at 37 and 4 °C. Purified OMVs induced tumour necrosis factor-α production in human macrophages at concentrations starting at 300 ng ml(-1). Experiments on HEK293-TLR2 and TLR4/MD-2 cell lines demonstrated a dominance of TLR2-dependent signalling pathways. In summary, we demonstrate binding, internalization and biological activity of L. pneumophila OMVs on human macrophages. Our data support OMV membrane fusion as a mechanism for the remote delivery of virulence factors to host cells.

  20. Risk Factors, Pattern and Clinical Outcome of Acute Graft Versus Host Disease in Acute Leukemia Patients Undergoing Allogeneic Stem Cell Transplant.

    PubMed

    Gupta, Alok; Punatar, Sachin; Gawande, Jayant; Mathew, Libin; Bagal, Bhausaheb; Kannan, Sadhana; Khattry, Navin

    2015-12-01

    We sought to determine risk factors, pattern and outcome of acute graft versus host disease (aGVHD) in seventy-seven acute leukemia patients who underwent allogeneic stem cell transplant at our centre from January 2008 to March 2013. GVHD prophylaxis with cyclosporine-methotrexate or cyclosporine-mycophenolate mofetil was used. Patients were divided in 2 groups, grade II-IV aGVHD (group A) and grade 0-I aGVHD (group B). Incidence of any grade and grade II-IV aGVHD was 44 and 18 %, respectively. The most common site of aGVHD was gastro-intestinal tract (65 %) followed by skin (35 %). Higher total nucleated cell (TNC) dose infused was associated with increased incidence of grade II-IV aGVHD. Incidence of relapse and incidence of slippage of chimerism was 21 and 36 % in group A while 37 and 27 % in group B respectively. Transplant related mortality (TRM) was 21 % in group A and 13 % in group B. Probability of OS and RFS at 4 years was 63 and 34 % in group A compared with 40 and 38 % in group B, respectively. We conclude that higher TNC dose infused is a risk factor for grade II-IV aGVHD with gut being the commonest site. Grade II-IV aGVHD did not have a significant impact on incidence of relapse, TRM and OS.

  1. TMPRSS2 Is a Host Factor That Is Essential for Pneumotropism and Pathogenicity of H7N9 Influenza A Virus in Mice

    PubMed Central

    Tarnow, Carolin; Engels, Géraldine; Arendt, Annika; Schwalm, Folker; Sediri, Hanna; Preuss, Annette; Nelson, Peter S.; Garten, Wolfgang; Klenk, Hans-Dieter; Gabriel, Gülsah

    2014-01-01

    ABSTRACT Cleavage of the hemagglutinin (HA) by host proteases is essential for the infectivity of influenza viruses. Here, we analyzed the role of the serine protease TMPRSS2, which activates HA in the human respiratory tract, in pathogenesis in a mouse model. Replication of the human H7N9 isolate A/Anhui/1/13 and of human H1N1 and H3N2 viruses was compared in TMPRSS2 knockout (TMPRSS2−/−) and wild-type (WT) mice. Knockout of TMPRSS2 expression inhibited H7N9 influenza virus replication in explants of murine tracheas, bronchi, and lungs. H1N1 virus replication was also strongly suppressed in airway explants of TMPRSS2−/− mice, while H3N2 virus replication was only marginally affected. H7N9 and H1N1 viruses were apathogenic in TMPRSS2−/− mice, whereas WT mice developed severe disease with mortality rates of 100% and 20%, respectively. In contrast, all H3N2 infected TMPRSS2−/− and WT mice succumbed to lethal infection. Cleavage analysis showed that H7 and H1 are efficiently activated by TMPRSS2, whereas H3 is less susceptible to the protease. Our data demonstrate that TMPRSS2 is a host factor that is essential for pneumotropism and pathogenicity of H7N9 and H1N1 influenza virus in mice. In contrast, replication of H3N2 virus appears to depend on another, not yet identified protease, supporting the concept that human influenza viruses differ in protease specificity. IMPORTANCE Cleavage of the hemagglutinin (HA) by host proteases is essential for the infectivity of influenza virus, but little is known about its relevance for pathogenesis in mammals. Here, we show that knockout mice that do not express the HA-activating protease TMPRSS2 are resistant to pulmonary disease with lethal outcome when infected with influenza A viruses of subtypes H7N9 and H1N1, whereas they are not protected from lethal H3N2 virus infection. These findings demonstrate that human influenza viruses differ in protease specificity, and that expression of the appropriate protease

  2. 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

  3. Use of lice to identify cowbird hosts

    USGS Publications Warehouse

    Hahn, D.C.; Price, R.D.; Osenton, P.C.

    2000-01-01

    The host specificity of avian lice (Phthiraptera) may be utilized by biologists to investigate the brood parasitism patterns of Brown-headed Cowbirds (Molothrus ater). As nestlings, brood parasites have a unique opportunity to encounter lice that are typically host specific. Lice are permanent hemimetabolic ectoparasites, a group found strictly on the body of the host, and they are transferred almost exclusively by bodily contact between hosts during care of young and at copulation. We investigated whether cowbird nestlings become infested with avian lice from their host parents and carry these lice away when they fledge, in effect bearing ectoparasite indicators of the species that raised them. The technique of examining the lice on cowbird fledglings to identify their foster parents would be much less costly than hiring a team of experts to determine parasitism patterns in the conventional way by finding hundreds of songbird nests. We examined 244 cowbird fledglings and found that they carried a rich fauna of lice representing 11 species and six genera, almost the entire spectrum of louse genera known to occur on passerines. We also examined 320 songbirds from 30 species, all known hosts of the Brown-headed Cowbird. As a group the host birds bore a diversity of louse species comparable to that on the fledgling cowbirds: 13 species of lice from seven genera. In contrast, most individual passerine host species yielded only 1 or 2 louse species, significantly fewer than the cowbird fledglings (p < 0.0001). Of 44 fledgling cowbirds carrying lice, 11 were linked to their probable avian foster parents via louse indicators, and these are the Wood Thrush and Red-winged Blackbird. Eighteen additional fledglings were linked to one of two possible foster parents. We concluded that cowbird fledglings do carry away host lice and this survey technique provides a partial assessment of local community parasitism patterns. The incomplete state of passerine louse taxonomy requires

  4. Factors affecting the microbial and chemical composition of silage. III. Effect of urea additions on maize silage.

    PubMed

    Mahmoud, S A; Abd-el-Hafez, A; Zaki, M M; Saleh, E A

    1978-01-01

    The effect of urea additions on the microbiological and chemical properties of silage, produced from young maize plants (Darawa stage), was studied. Urea treatments, i.e., 0.25%, 0.50%, 0.75%, and 1.00%, stimulated higher densities of the desired microorganisms than the control, while undesired organisms showed lower counts (proteolytic and saccharolytic anaerobes). Addition of 0.25 to 0.50% or urea resulted in the production of high quality silage with pleasant small and high nutritive value, as confirmed by the various microbiological and chemical analyses conducted. Higher levels (0.75 and 1.00%) of urea decreased the quality of the product. PMID:29417

  5. c-Fos: an AP-1 transcription factor with an additional cytoplasmic, non-genomic lipid synthesis activation capacity.

    PubMed

    Caputto, Beatriz L; Cardozo Gizzi, Andrés M; Gil, Germán A

    2014-09-01

    The mechanisms that co-ordinately activate lipid synthesis when high rates of membrane biogenesis are needed to support cell growth are largely unknown. c-Fos, a well known AP-1 transcription factor, has emerged as a unique protein with the capacity to associate to specific enzymes of the pathway of synthesis of phospholipids at the endoplasmic reticulum and activate their synthesis to accompany genomic decisions of growth. Herein, we discuss this cytoplasmic, non-genomic effect of c-Fos in the context of other mechanisms that have been proposed to regulate lipid synthesis.

  6. 42 CFR 136.408 - What are other factors, in addition to the minimum standards of character, that may be considered...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false What are other factors, in addition to the minimum standards of character, that may be considered in determining placement of an individual in a position that involves regular contact with or control over Indian children? 136.408 Section 136.408 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT...

  7. 42 CFR 136.408 - What are other factors, in addition to the minimum standards of character, that may be considered...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false What are other factors, in addition to the minimum standards of character, that may be considered in determining placement of an individual in a position that involves regular contact with or control over Indian children? 136.408 Section 136.408 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT...

  8. Ameliorative effects of telmisartan on the inflammatory response and impaired spatial memory in a rat model of Alzheimer's disease incorporating additional cerebrovascular disease factors.

    PubMed

    Shindo, Taro; Takasaki, Kotaro; Uchida, Kanako; Onimura, Rika; Kubota, Kaori; Uchida, Naoki; Irie, Keiichi; Katsurabayashi, Shutaro; Mishima, Kenichi; Nishimura, Ryoji; Fujiwara, Michihiro; Iwasaki, Katsunori

    2012-01-01

    Telmisartan, an angiotensin type 1 receptor blocker, is used in the management of hypertension to control blood pressure. In addition, telmisartan has a partial agonistic effect on peroxisome proliferator activated receptor γ (PPARγ). Recently, the effects of telmisartan on spatial memory or the inflammatory response were monitored in a mouse model of Alzheimer's disease (AD). However, to date, no studies have investigated the ameliorative effects of telmisartan on impaired spatial memory and the inflammatory response in an AD animal model incorporating additional cerebrovascular disease factors. In this study, we examined the effect of telmisartan on spatial memory impairment and the inflammatory response in a rat model of AD incorporating additional cerebrovascular disease factors. Rats were subjected to cerebral ischemia and an intracerebroventricular injection of oligomeric or aggregated amyloid-β (Aβ). Oral administration of telmisartan (0.3, 1, 3 mg/kg/d) seven days after ischemia and Aβ treatment resulted in better performance in the eight arm radial maze task in a dose-dependent manner. Telmisartan also reduced tumor necrosis factor α mRNA expression in the hippocampal region of rats with impaired spatial memory. These effects of telmisartan were antagonized by GW9662, an antagonist of PPARγ. These results suggest that telmisartan has ameliorative effects on the impairment of spatial memory in a rat model of AD incorporating additional cerebrovascular disease factors via its anti-inflammatory effect.

  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. Structural basis for the requirement of additional factors for MLL1 SET domain activity and recognition of epigenetic marks.

    PubMed

    Southall, Stacey M; Wong, Poon-Sheng; Odho, Zain; Roe, S Mark; Wilson, Jon R

    2009-01-30

    The mixed-lineage leukemia protein MLL1 is a transcriptional regulator with an essential role in early development and hematopoiesis. The biological function of MLL1 is mediated by the histone H3K4 methyltransferase activity of the carboxyl-terminal SET domain. We have determined the crystal structure of the MLL1 SET domain in complex with cofactor product AdoHcy and a histone H3 peptide. This structure indicates that, in order to form a well-ordered active site, a highly variable but essential component of the SET domain must be repositioned. To test this idea, we compared the effect of the addition of MLL complex members on methyltransferase activity and show that both RbBP5 and Ash2L but not Wdr5 stimulate activity. Additionally, we have determined the effect of posttranslational modifications on histone H3 residues downstream and upstream from the target lysine and provide a structural explanation for why H3T3 phosphorylation and H3K9 acetylation regulate activity. PMID:19187761

  11. Epidermal growth factor (EGF)-receptor is phosphorylated at threonine-654 in A431 cells following EGF addition

    SciTech Connect

    Whiteley, B.; Glaser, L.

    1986-05-01

    It has been shown that activation of protein kinase C by tumor-promoting phorbol diesters causes phorphorylation of the EGF-receptor at threonine-654 and is believed to thereby regulate the EGF receptor tyrosine kinase and EGF binding activity. In their present studies, /sup 32/P-labeled A431 cells were treated with and without 10 nM phorbol 12-myristate 13-acetate (PMA), or with 200 ng/ml EGF. Analysis of /sup 32/P-labeled EGF receptor tryptic phosphopeptides by reverse-phase HPLC confirmed the known effects of PMA and revealed that EGF caused phosphorylation at threonine-654 as well as various tyrosine residues. This effect occurred as early as 1 minute after EGF addition and was maximal after 5 minutes. The magnitude of the response appears to be 50% of a 15 minute treatment with 10 nM PMA. Direct measurement of diacylglycerol using an E. coli diacylglycerol kinase confirmed that EGF-stimulated phosphoinositide turnover could cause very rapid activation of protein kinase C. These results imply that protein kinase C is playing a role in negative modulation of EGF-receptor activity following EGF addition to A431 cells.

  12. 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.

  13. 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.

  14. Transcription from fusion promoters generated during transposition of transposon Tn4652 is positively affected by integration host factor in Pseudomonas putida.

    PubMed

    Teras, R; Hõrak, R; Kivisaar, M

    2000-02-01

    We have previously shown that both ends of the Tn3 family transposon Tn4652 contain integration host factor (IHF) binding sites and that IHF positively regulates expression of the Tn4652 transposase gene tnpA in Pseudomonas putida (R. Hõrak, and M. Kivisaar, J. Bacteriol. 180:2822-2829, 1998). Tn4652 can activate silent genes by creating fusion promoters during the transposition. The promoters are created as fusions between the -35 hexamer provided by the terminal inverted repeats of Tn4652 and the -10 hexamers in the target DNA. Two fusion promoters, PRA1 and PLA1, that contain sequences of the right and left termini of Tn4652, respectively, were chosen for the study of mechanisms of transcription activation. Gel mobility shift analysis using crude extracts from P. putida cells allowed us to detect specific binding of P. putida IHF to the ends of the transposon Tn4652. We found that the rate of transcription from the fusion promoter PRA1 is enhanced by IHF. Notably, the positive effect of IHF on transcription from the promoter PRA1 appeared only when cells of P. putida reached the stationary growth phase. We speculate that the intracellular concentration of IHF might be critical for the in vivo effect of IHF on transcription from the fusion promoters in P. putida. In the case of PLA1, the mechanism of transcription modulation by IHF is different than that observed for PRA1. Our results demonstrate that transcription of neighboring genes from outwardly directed promoters at the ends of a mobile DNA element could be influenced by the same factors that control transposition of the element. PMID:10633090

  15. Seasonal variation in abiotic factors and ferulic acid toxicity in snail-attractant pellets against the intermediate host snail Lymnaea acuminata.

    PubMed

    Agrahari, P; Singh, D K

    2013-11-01

    Laboratory evaluation was made to access the seasonal variations in abiotic environmental factors temperature, pH, dissolved oxygen, carbon dioxide, electrical conductivity and ferulic acid toxicity in snail-attractant pellets (SAP) against the intermediate host snail Lymnaea acuminata in each month of the years 2010 and 2011. On the basis of a 24-h toxicity assay, it was noted that lethal concentration values of 4.03, 3.73% and 4.45% in SAP containing starch and 4.16, 4.23% and 4.29% in SAP containing proline during the months of May, June and September, respectively, were most effective in killing the snails, while SAP containing starch/proline + ferulic acid was least effective in the month of January/February (24-h lethal concentration value was 7.67%/7.63% in SAP). There was a significant positive correlation between lethal concentration value of ferulic acid containing SAP and levels of dissolved O2 /pH of water in corresponding months. On the contrary, a negative correlation was observed between lethal concentration value and dissolved CO2 /temperature of test water in the same months. To ascertain that such a relationship between toxicity and abiotic factors is not co-incidental, the nervous tissue of treated (40% and 80% of 24-h lethal concentration value) and control group of snails was assayed for the activity of acetylcholinesterase (AChE) in each of the 12 months of the same year. There was a maximum inhibition of 58.43% of AChE, in snails exposed to 80% of the 24-h lethal concentration value of ferulic acid + starch in the month of May. This work shows conclusively that the best time to control snail population with SAP containing ferulic acid is during the months of May, June and September.

  16. 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

  17. Influence of physico-chemical factors on leaching of chemical additives from aluminium foils used for packaging of food materials.

    PubMed

    Ojha, Priyanka; Ojha, C S; Sharma, V P

    2007-01-01

    In recent years, the use of aluminium foils to wrap foodstuff and commodities has been increased to a great extent. Aluminium was found to leach out from the foil in different simulants particularly in distilled water, acidic and alkaline medium at 60 +/- 2 degrees C for 2 hours and 40 +/- 2 degrees C for 24 hours. The migration was found to be above the permissible limit as laid down by WHO guidelines, that is of 0.2 mg/L of water. The protocol used for this study was based on the recommendation of Bureau of Indian Standard regarding the migration of chemical additives from packaging materials used to pack food items. Migration of the aluminium metal was found significantly higher in acidic and aqueous medium in comparison to alcoholic and saline medium. Higher temperature conditions also enhanced the rate of migration of aluminium in acidic and aqueous medium. Leaching of aluminium metal occurred in double distilled water, acetic acid 3%, normal saline and sodium carbonate, except ethanol 8%, in which aluminium migration was below the detection limit of the instrument where three brands of the aluminium foil samples studied.

  18. 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.

  19. 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

  20. 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

  1. 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...

  2. Symbolic integration of a product of two spherical Bessel functions with an additional exponential and polynomial factor

    NASA Astrophysics Data System (ADS)

    Gebremariam, B.; Duguet, T.; Bogner, S. K.

    2010-06-01

    We present a Mathematica package that performs the symbolic calculation of integrals of the form ∫0∞exj(x)j(x)dx where j(x) and j(x) denote spherical Bessel functions of integer orders, with ν⩾0 and μ⩾0. With the real parameter u>0 and the integer n, convergence of the integral requires that n+ν+μ⩾0. The package provides analytical result for the integral in its most simplified form. In cases where direct Mathematica implementations succeed in evaluating these integrals, the novel symbolic method implemented in this work obtains the same result and in general, it takes a fraction of the time required for the direct implementation. We test the accuracy of such analytical expressions by comparing the results with their numerical counterparts. Program summaryProgram title: SymbBesselJInteg Catalogue identifier: AEFY_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEFY_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.: 275 934 No. of bytes in distributed program, including test data, etc.: 399 705 Distribution format: tar.gz Programming language: Mathematica 7.1 Computer: Any computer running Mathematica 6.0 and later versions. Operating system: Windows Xp, Linux/Unix. RAM: 256 Mb Classification: 5. Nature of problem: Integration, both analytical and numerical, of products of two spherical Bessel functions with an exponential and polynomial multiplying factor can be a very complex task depending on the orders of the spherical Bessel functions. The Mathematica package discussed in this paper solves this problem using a novel symbolic approach. Solution method: The problem is first cast into a related limit problem which can be broken into two related subproblems involving exponential and exponential integral functions. Solving the cores of each

  3. 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

  4. 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

  5. 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

  6. 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.

  7. Limited Agreement of Independent RNAi Screens for Virus-Required Host Genes Owes More to False-Negative than False-Positive Factors

    PubMed Central

    Wang, Zhishi; Craven, Mark; Newton, Michael A.; Ahlquist, Paul

    2013-01-01

    Systematic, genome-wide RNA interference (RNAi) analysis is a powerful approach to identify gene functions that support or modulate selected biological processes. An emerging challenge shared with some other genome-wide approaches is that independent RNAi studies often show limited agreement in their lists of implicated genes. To better understand this, we analyzed four genome-wide RNAi studies that identified host genes involved in influenza virus replication. These studies collectively identified and validated the roles of 614 cell genes, but pair-wise overlap among the four gene lists was only 3% to 15% (average 6.7%). However, a number of functional categories were overrepresented in multiple studies. The pair-wise overlap of these enriched-category lists was high, ∼19%, implying more agreement among studies than apparent at the gene level. Probing this further, we found that the gene lists implicated by independent studies were highly connected in interacting networks by independent functional measures such as protein-protein interactions, at rates significantly higher than predicted by chance. We also developed a general, model-based approach to gauge the effects of false-positive and false-negative factors and to estimate, from a limited number of studies, the total number of genes involved in a process. For influenza virus replication, this novel statistical approach estimates the total number of cell genes involved to be ∼2,800. This and multiple other aspects of our experimental and computational results imply that, when following good quality control practices, the low overlap between studies is primarily due to false negatives rather than false-positive gene identifications. These results and methods have implications for and applications to multiple forms of genome-wide analysis. PMID:24068911

  8. Turnip Mosaic Virus Genome-Linked Protein VPg Binds C-Terminal Region of Cap-Bound Initiation Factor 4E Orthologue Without Exhibiting Host Cellular Specificity

    PubMed Central

    Okade, Hayato; Fujita, Yuki; Miyamoto, Saori; Tomoo, Koji; Muto, Shinji; Miyoshi, Hiroshi; Natsuaki, Tomohide; Rhoads, Robert E.; Ishida, Toshimasa

    2014-01-01

    To investigate the binding specificity of turnip mosaic virus (TuMV) viral protein-genome linked (VPg) with translation initiation factor 4E, we evaluated here the kinetic parameters for the interactions of human eIF4E, Caenorhabditis elegans IFE-3 and IFE-5 and Arabidopsis eIFiso4E, by surface plasmon resonance (SPR). The results indicated that TuMV VPg does not show a binding preference for Arabidopsis eIFiso4E, even though it is from a host species whereas the other eIF4E orthologues are not. Surprisingly, the effect of m7GTP on both the rate constants and equilibrium binding constants for the interactions of VPg differed for the four eIF4E orthologues. In the case of eIFiso4E and IFE-3, m7GTP increased kon, but for eIF4E and IFE-5, it decreased kon. To provide insight into the structural basis for these differences in VPg binding, tertiary structures of the eIF4E orthologues were predicted on the basis of the previously determined crystal structure of m7GpppA-bound human eIF4E. The results suggested that in cap-bound eIF4E orthologues, the VPg binds to the C-terminal region, which constitutes one side of the entrance to the cap-binding pocket, whereas in the cap-free state, VPg binds to the widely opened cap-binding pocket and its surrounding region. The binding of VPg to the C-terminal region was confirmed by the SPR analyses of N- or C-terminal residues-deleted eIF4E orthologues. PMID:19122207

  9. 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

  10. Polymorphisms in host genes encoding NOSII, C-reactive protein, and adhesion molecules thrombospondin and E-selectin are risk factors for Plasmodium falciparum malaria in India.

    PubMed

    Kanchan, K; Pati, S S; Mohanty, S; Mishra, S K; Sharma, S K; Awasthi, S; Venkatesh, V; Habib, S

    2015-10-01

    Cytoadherence of Plasmodium falciparum-infected red blood cells (RBCs) in host microvasculature and complex regulation of the immune response are important contributors to the clinical outcome of disease. We tested the association of 23 single nucleotide polymorphisms (SNPs) and a microsatellite repeat in adhesion molecule genes THBS1 and ESEL, and immune regulatory molecule genes NOSII, CRP, and MBL2 with falciparum malaria in populations residing in a malaria-endemic and a non-endemic region of India. The THBS1 haplotype CCCCA (rs1478604, rs7170682, rs2664141, rs12912082, rs3743125) was a risk factor in the endemic region (relative risk = 3.78) and an ESEL SNP (rs5368, His468Tyr) associated with cerebral malaria (CM) [CM vs. non-cerebral malaria (NCM), odds ratio (OR) = 2.23, p = 0.03]. In the non-endemic region, an ESEL 3'UTR SNP (rs5359) associated with enhanced risk of disease (OR = 3.62, p = 1 × 10(-4)) and the CT genotype of the CRP promoter SNP (C/T/A) strongly associated with protection (severe vs. control, OR = 0.29, p = 6 × 10(-5)). Long repeat alleles of the NOSII promoter microsatellite (CCTTT)n exhibited strong association with protection and the NOSII ATG haplotype (rs3729508, rs2297520, rs9282801) was strongly protective against severe malaria in both regions (endemic, severe vs. control, OR = 0.05, p = 0.0001; non-endemic, severe vs. control, OR = 0.3, p = 1 × 10(-5)). Our results suggest differential contribution of variants of the investigated genes in determining the outcome of malaria in Indian populations.

  11. 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.

  12. Analysis of Air Toxics From NOAA WP-3 Aircraft Measurements During the TexAQS 2006 Campaign: Comparison With Emission Inventories and Additive Inhalation Risk Factors

    NASA Astrophysics Data System (ADS)

    Del Negro, L. A.; Warneke, C.; de Gouw, J. A.; Atlas, E.; Lueb, R.; Zhu, X.; Pope, L.; Schauffler, S.; Hendershot, R.; Washenfelder, R.; Fried, A.; Richter, D.; Walega, J. G.; Weibring, P.

    2007-12-01

    Benzene and nine other air toxics classified as human carcinogens by the International Agency for Research on Cancer (IARC) were measured from the NOAA WP-3 aircraft during the TexAQS 2006 campaign. In-situ measurements of benzene, measured with a PTR-MS instrument, are used to estimate emission fluxes for comparison with point source emission inventories developed by the Texas Commission on Environmental Quality. Mean and median mixing ratios for benzene, acetaldehyde, formaldehyde, 1,3-butadiene, carbon tetrachloride, chloroform, 1,2-dichloroethane, dibromoethane, dichloromethane, and vinyl chloride, encountered over the city of Houston during the campaign, are combined with inhalation unit risk factor values developed by the California Environmental Protection Agency and the United States Environmental Protection Agency to estimate the additive inhalation risk factor. This additive risk factor represents the risk associated with lifetime (70 year) exposure at the levels measured and should not be used as an absolute indicator of risk to individuals. However, the results are useful for assessments of changing relative risk over time, and for identifying dominant contributions to the overall air toxic risk.

  13. 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

  14. 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

  15. 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.

  16. The effect of host nutritional quality on multiple components of Trichogramma brassicae fitness.

    PubMed

    Kishani Farahani, H; Ashouri, A; Zibaee, A; Abroon, P; Alford, L

    2016-10-01

    For parasitoids, the host represents the sole source of nutrients for the developing immature. Subsequently, host quality is an important factor affecting immature development and the resulting fitness of the emerging parasitoid, with impacts on fecundity, longevity and offspring sex ratio. Host age is an integral component of host quality and a key factor in host selection by the female parasitoid. The current study aimed to investigate the effect of decreasing host quality (determined by increasing host age) on adult life history traits (size, wing loading, longevity, and fecundity) and nutritional reserves (protein, lipid and glycogen concentrations) of the parasitoid Trichogramma brassicae. Higher quality hosts resulted in the production of larger offspring with increased resource reserves and enhanced mobility. One-day-old eggs contained significantly more protein and triglyceride than 25- and 45-day-old eggs. Quality of host and fitness of reared wasps decreased due to host aging. Parasitoids reared on 1-day-old hosts were larger, with greater fecundity and longevity, a reduced wind loading index, and produced a higher proportion of female offspring when compared with those reared on 25- and 45-day-old hosts. In addition, wasps reared on 1-day-old hosts contained higher energy resources, as determined by triglyceride, glycogen and protein reserves, which are essential to successful offspring production. One-day-old hosts can therefore be considered as the best age for producing wasps with greater fitness, since they contain the highest amount of protein, glycogen, and triglyceride. This has implications for the mass rearing of T. brassicae and enhancing the efficacy of this biological control agent. PMID:27215662

  17. The effect of host nutritional quality on multiple components of Trichogramma brassicae fitness.

    PubMed

    Kishani Farahani, H; Ashouri, A; Zibaee, A; Abroon, P; Alford, L

    2016-10-01

    For parasitoids, the host represents the sole source of nutrients for the developing immature. Subsequently, host quality is an important factor affecting immature development and the resulting fitness of the emerging parasitoid, with impacts on fecundity, longevity and offspring sex ratio. Host age is an integral component of host quality and a key factor in host selection by the female parasitoid. The current study aimed to investigate the effect of decreasing host quality (determined by increasing host age) on adult life history traits (size, wing loading, longevity, and fecundity) and nutritional reserves (protein, lipid and glycogen concentrations) of the parasitoid Trichogramma brassicae. Higher quality hosts resulted in the production of larger offspring with increased resource reserves and enhanced mobility. One-day-old eggs contained significantly more protein and triglyceride than 25- and 45-day-old eggs. Quality of host and fitness of reared wasps decreased due to host aging. Parasitoids reared on 1-day-old hosts were larger, with greater fecundity and longevity, a reduced wind loading index, and produced a higher proportion of female offspring when compared with those reared on 25- and 45-day-old hosts. In addition, wasps reared on 1-day-old hosts contained higher energy resources, as determined by triglyceride, glycogen and protein reserves, which are essential to successful offspring production. One-day-old hosts can therefore be considered as the best age for producing wasps with greater fitness, since they contain the highest amount of protein, glycogen, and triglyceride. This has implications for the mass rearing of T. brassicae and enhancing the efficacy of this biological control agent.

  18. 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

  19. 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.

  20. 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...

  1. A mathematical modelling framework for linked within-host and between-host dynamics for infections with free-living pathogens in the environment.

    PubMed

    Garira, Winston; Mathebula, Dephney; Netshikweta, Rendani

    2014-10-01

    In this study we develop a mathematical modelling framework for linking the within-host and between-host dynamics of infections with free-living pathogens in the environment. The resulting linked models are sometimes called immuno-epidemiological models. However, there is still no generalised framework for linking the within-host and between-host dynamics of infectious diseases. Furthermore, for infections with free-living pathogens in the environment, there is an additional stumbling block in that there is a gap in knowledge on how environmental factors (through water, air, soil, food, fomites, etc.) alter many aspects of such infections including susceptibility to infective dose, persistence of infection, pathogen shedding and severity of the disease. In this work, we link the two subsystems (within-host and between-host models) by identifying the within-host and between-host variables and parameters associated with the environmental dynamics of the pathogen and then design a feedback of the variables and parameters across the within-host and between-host models using human schistosomiasis as a case study. We study the mathematical properties of the linked model and show that the model is epidemiologically well-posed. Using results from the analysis of the endemic equilibrium expression, the disease reproductive number R0, and numerical simulations of the full model, we adequately account for the reciprocal influence of the linked within-host and between-host models. In particular, we illustrate that for human schistosomiasis, the outcome of infection at the individual level determines if, when and how much the individual host will further transmit the infectious agent into the environment, eventually affecting the spread of the infection in the host population. We expect the conceptual modelling framework developed here to be applicable to many infectious disease with free-living pathogens in the environment beyond the specific disease system of human

  2. Characterization of DNA Binding Property of the HIV-1 Host Factor and Tumor Suppressor Protein Integrase Interactor 1 (INI1/hSNF5)

    PubMed Central

    Das, Supratik; Thangamuniyandi, Muruganandan; Dasgupta, Saumya; Chongdar, Nipa; Kumar, Gopinatha Suresh; Basu, Gautam

    2013-01-01

    Integrase Interactor 1 (INI1/hSNF5) is a component of the hSWI/SNF chromatin remodeling complex. The INI1 gene is either deleted or mutated in rhabdoid cancers like ATRT (Atypical terratoid and rhabdoid tumor). INI1 is also a host factor for HIV-1 replication. INI1 binds DNA non-specifically. However, the mechanism of DNA binding and its biological role are unknown. From agarose gel retardation assay (AGRA), Ni-NTA pull-down and atomic force microscopy (AFM) studies we show that amino acids 105–183 of INI1 comprise the minimal DNA binding domain (DBD). The INI1 DBD is absent in plants and in yeast SNF5. It is present in Caenorhabditis elegans SNF5, Drosophila melanogaster homologue SNR1 and is a highly conserved domain in vertebrates. The DNA binding property of this domain in SNR1, that is only 58% identical to INI1/hSNF5, is conserved. Analytical ultracentrifugation studies of INI1 DBD and INI1 DBD:DNA complexes at different concentrations show that the DBD exists as a monomer at low protein concentration and two molecules of monomer binds one molecule of DNA. At high protein concentration, it exists as a dimer and binds two DNA molecules. Furthermore, isothermal calorimetry (ITC) experiments demonstrate that the DBD monomer binds DNA with a stoichiometry (N) of ∼0.5 and Kd  = 0.94 µM whereas the DBD dimer binds two DNA molecules sequentially with K’d1 = 222 µM and K’d2 = 1.16 µM. Monomeric DBD binding to DNA is enthalpy driven (ΔH = –29.9 KJ/mole). Dimeric DBD binding to DNA is sequential with the first binding event driven by positive entropy (ΔH’1 = 115.7 KJ/mole, TΔS’1 = 136.8 KJ/mole) and the second binding event driven by negative enthalpy (ΔH’2 = –106.3 KJ/mole, TΔS’2 = –75.7 KJ/mole). Our model for INI1 DBD binding to DNA provides new insights into the mechanism of DNA binding by INI1. PMID:23861745

  3. Surveillance of feral swine for Trichinella spp. and Toxoplasma gondii in the USA and host-related factors associated with infection.

    PubMed

    Hill, D E; Dubey, J P; Baroch, J A; Swafford, S R; Fournet, V F; Hawkins-Cooper, D; Pyburn, D G; Schmit, B S; Gamble, H R; Pedersen, K; Ferreira, L R; Verma, S K; Ying, Y; Kwok, O C H; Feidas, H; Theodoropoulos, G

    2014-10-15

    Trichinella spp. and Toxoplasma gondii are important zoonotic parasites that infect warm blooded animals and humans worldwide. Among domesticated food animals, pigs are the main host for Trichinella spiralis. Pigs, chickens, sheep, and goats are known to be infected with T. gondii at varying rates, depending on husbandry. Infections in wildlife with these parasites are generally higher than in domesticated species. Feral swine act as reservoirs of infection in the sylvatic ecosystem for Trichinella spp. and T. gondii, acting as sources of infection for peridomestic carnivores whose home ranges overlap with domestic pigs. Feral swine can have direct contact with non-biosecure domestic pigs, presenting opportunity for direct disease transmission through cannibalistic behavior. Determination of the prevalence of Trichinella spp. and T. gondii infection in feral swine is needed to understand the risk of transmission of these parasites to domestic pigs. A cross-sectional serological survey was conducted between 2006 and 2010 to estimate the antibody prevalence of Trichinella spp. and T. gondii and risk factors associated with infection in feral swine in the USA. Serum samples were tested from 3247 feral pigs from 32 states; results are reported from 26 states. Maximum entropy ecological niche modeling and spatial scan statistic were utilized to predict the geographic range and to examine clusters of infection of Trichinella spp. and T. gondii in feral pigs. The seroprevalence of antibodies to Trichinella spp. and T. gondii was 3.0% and 17.7%, respectively. Species distribution modeling indicated that the most probable distribution areas for both parasites was similar, concentrated primarily in the South and the Midwest regions of the USA. A follow up survey conducted during 2012-2013 revealed that 2.9% of 984 sampled feral swine were seropositive for Trichinella spp., and 28.4% were seropositive for T. gondii. Three hundred and thirty (330) tongues were collected from

  4. Specific and non-specific interactions of integration host factor with DNA: thermodynamic evidence for disruption of multiple IHF surface salt-bridges coupled to DNA binding.

    PubMed

    Holbrook, J A; Tsodikov, O V; Saecker, R M; Record, M T

    2001-07-01

    Site-specific DNA binding of architectural protein integration host factor (IHF) is involved in formation of functional multiprotein-DNA assemblies in Escherichia coli, while non-specific binding of IHF and other histone-like proteins serves to structure the nucleoid. Here, we report an isothermal titration calorimetry study of the thermodynamics of binding IHF to a 34 bp fragment composed entirely of the specific H' site from lambda-phage DNA. At low to moderate [K(+)] (60-100 mM), strong competition is observed between specific and non-specific binding as a result of a low specificity ratio (approximately 10(2)) and a very small non-specific site size. In this [K(+)] range, both specific and non-specific binding are enthalpy-driven, with large negative enthalpy, entropy and heat capacity changes and binding constants that are insensitive to [K(+)]. Above 100 mM K(+), only specific binding is observed, and both the binding constant and the magnitudes of enthalpy, entropy and heat capacity changes all decrease strongly with increasing [K(+)]. When interpreted in the context of the structure of the specific complex, the thermodynamics provide compelling evidence for a previously unrecognized design principle by which proteins that form extensive binding interfaces with nucleic acids control binding constants, binding site sizes and effects of temperature and ion concentrations on stability and specificity. We propose that up to 22 of the 23 IHF cationic side-chains that are located within 6 A of DNA phosphate oxygen atoms in the complex, are masked in the absence of DNA by pairing with anionic carboxylate groups in intramolecular salt-bridges (dehydrated ion-pairs). These salt-bridges increase in stability with increasing temperature and decreasing [K(+)]. To explain the unusual thermodynamics of IHF-DNA interactions, we propose that both specific and non-specific binding at low [K(+)] require disruption of salt-bridges (as many as 18 for specific binding) whereupon

  5. 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

  6. 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.

  7. 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.

  8. 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...

  9. 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...

  10. Outpatient Management of Postbiopsy Pneumothorax with Small-Caliber Chest Tubes: Factors Affecting the Need for Prolonged Drainage and Additional Interventions

    SciTech Connect

    Gupta, Sanjay Hicks, Marshall E.; Wallace, Michael J.; Ahrar, Kamran; Madoff, David C.; Murthy, Ravi

    2008-03-15

    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 for pain control (n = 2). No further interventions were required in 146 patients (76.4%), with successful removal of the chest tubes the day after the biopsy procedure. Prolonged catheter drainage (mean, 4.3 days) was required in 44 patients (23%). Nineteen patients (9.9%) underwent additional interventions for management of pneumothorax. Presence of emphysema was noted more frequently in patients who required additional interventions or prolonged chest tube drainage than in those who did not (51.1% vs. 24.7%; p = 0.001).We conclude that use of the Heimlich valve allows safe and successful outpatient treatment of most patients requiring chest tube placement for postbiopsy pneumothorax. Additional interventions or prolonged chest tube drainage are needed more frequently in patients with emphysema in the needle path.

  11. Transcriptional Regulation of Zein Gene Expression in Maize through the Additive and Synergistic Action of opaque2, Prolamine-Box Binding Factor, and O2 Heterodimerizing Proteins

    PubMed Central

    Zhang, Zhiyong; Yang, Jun; Wu, Yongrui

    2015-01-01

    Maize (Zea mays) zeins are some of the most abundant cereal seed storage proteins (SSPs). Their abundance influences kernel hardness but compromises its nutritional quality. Transcription factors regulating the expression of zein and other SSP genes in cereals are endosperm-specific and homologs of maize opaque2 (O2) and prolamine-box binding factor (PBF). This study demonstrates that the ubiquitously expressed transcription factors, O2 heterodimerizing proteins (OHPs), specifically regulate 27-kD γ-zein gene expression (through binding to an O2-like box in its promoter) and interact with PBF. The zein content of double mutants OhpRNAi;o2 and PbfRNAi;o2 and the triple mutant PbfRNAi;OhpRNAi;o2 is reduced by 83, 89, and 90%, respectively, compared with the wild type. The triple mutant developed the smallest zein protein bodies, which were merely one-tenth the wild type’s size. Total protein levels in these mutants were maintained in a relatively constant range through proteome rebalancing. These data show that OHPs, O2, and PBF are master regulators of zein storage protein synthesis, acting in an additive and synergistic mode. The differential expression patterns of OHP and O2 genes may cause the slight differences in the timing of 27-kD γ-zein and 22-kD α-zein accumulation during protein body formation. PMID:25901087

  12. Graft monocytic myeloid-derived suppressor cell content predicts the risk of acute graft-versus-host disease after allogeneic transplantation of granulocyte colony-stimulating factor-mobilized peripheral blood stem cells.

    PubMed

    Vendramin, Antonio; Gimondi, Silvia; Bermema, Anisa; Longoni, Paolo; Rizzitano, Sara; Corradini, Paolo; Carniti, Cristiana

    2014-12-01

    Myeloid-derived suppressor cells (MDSCs) are powerful immunomodulatory cells that in mice play a role in infectious and inflammatory disorders, including acute graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation. Their relevance in clinical acute GVHD is poorly known. We analyzed whether granulocyte colony-stimulating factor (G-CSF) administration, used to mobilize hematopoietic stem cells, affected the frequency of MDSCs in the peripheral blood stem cell grafts of 60 unrelated donors. In addition, we evaluated whether the MDSC content in the peripheral blood stem cell grafts affected the occurrence of acute GVHD in patients undergoing unrelated donor allogeneic stem cell transplantation. Systemic treatment with G-CSF induces an expansion of myeloid cells displaying the phenotype of monocytic MDSCs (Lin(low/neg)HLA-DR(-)CD11b(+)CD33(+)CD14(+)) with the ability to suppress alloreactive T cells in vitro, therefore meeting the definition of MDSCs. Monocytic MDSC dose was the only graft parameter to predict acute GVHD. The cumulative incidence of acute GVHD at 180 days after transplantation for recipients receiving monocytic MDSC doses below and above the median was 63% and 22%, respectively (P = .02). The number of monocytic MDSCs infused did not impact the relapse rate or the transplant-related mortality rate (P > .05). Although further prospective studies involving larger sample size are needed to validate the exact monocytic MDSC graft dose that protects from acute GVHD, our results strongly suggest the modulation of G-CSF might be used to affect monocytic MDSCs graft cell doses for prevention of acute GVHD.

  13. Ethanol production by recombinant hosts

    DOEpatents

    Ingram, Lonnie O.; Beall, David S.; Burchhardt, Gerhard F. H.; Guimaraes, Walter V.; Ohta, Kazuyoshi; Wood, Brent E.; Shanmugam, Keelnatham T.

    1995-01-01

    Novel plasmids comprising genes which code for the alcohol dehydrogenase and pyruvate decarboxylase are described. Also described are recombinant hosts which have been transformed with genes coding for alcohol dehydrogenase and pyruvate. By virtue of their transformation with these genes, the recombinant hosts are capable of producing significant amounts of ethanol as a fermentation product. Also disclosed are methods for increasing the growth of recombinant hosts and methods for reducing the accumulation of undesirable metabolic products in the growth medium of these hosts. Also disclosed are recombinant host capable of producing significant amounts of ethanol as a fermentation product of oligosaccharides and plasmids comprising genes encoding polysaccharases, in addition to the genes described above which code for the alcohol dehydrogenase and pyruvate decarboxylase. Further, methods are described for producing ethanol from oligomeric feedstock using the recombinant hosts described above. Also provided is a method for enhancing the production of functional proteins in a recombinant host comprising overexpressing an adhB gene in the host. Further provided are process designs for fermenting oligosaccharide-containing biomass to ethanol.

  14. Ethanol production by recombinant hosts

    DOEpatents

    Fowler, David E.; Horton, Philip G.; Ben-Bassat, Arie

    1996-01-01

    Novel plasmids comprising genes which code for the alcohol dehydrogenase and pyruvate decarboxylase are described. Also described are recombinant hosts which have been transformed with genes coding for alcohol dehydrogenase and pyruvate. By virtue of their transformation with these genes, the recombinant hosts are capable of producing significant amounts of ethanol as a fermentation product. Also disclosed are methods for increasing the growth of recombinant hosts and methods for reducing the accumulation of undesirable metabolic products in the growth medium of these hosts. Also disclosed are recombinant host capable of producing significant amounts of ethanol as a fermentation product of oligosaccharides and plasmids comprising genes encoding polysaccharases, in addition to the genes described above which code for the alcohol dehydrogenase and pyruvate decarboxylase. Further, methods are described for producing ethanol from oligomeric feedstock using the recombinant hosts described above. Also provided is a method for enhancing the production of functional proteins in a recombinant host comprising overexpressing an adhB gene in the host. Further provided are process designs for fermenting oligosaccharide-containing biomass to ethanol.

  15. Castrating parasites and colonial hosts.

    PubMed

    Hartikainen, H; Okamura, B

    2012-04-01

    Trajectories of life-history traits such as growth and reproduction generally level off with age and increasing size. However, colonial animals may exhibit indefinite, exponential growth via modular iteration thus providing a long-lived host source for parasite exploitation. In addition, modular iteration entails a lack of germ line sequestration. Castration of such hosts by parasites may therefore be impermanent or precluded, unlike the general case for unitary animal hosts. Despite these intriguing correlates of coloniality, patterns of colonial host exploitation have not been well studied. We examined these patterns by characterizing the responses of a myxozoan endoparasite, Tetracapsuloides bryosalmonae, and its colonial bryozoan host, Fredericella sultana, to 3 different resource levels. We show that (1) the development of infectious stages nearly always castrates colonies regardless of host condition, (2) castration reduces partial mortality and (3) development of transmission stages is resource-mediated. Unlike familiar castrator-host systems, this system appears to be characterized by periodic rather than permanent castration. Periodic castration may be permitted by 2 key life history traits: developmental cycling of the parasite between quiescent (covert infections) and virulent infectious stages (overt infections) and the absence of germ line sequestration which allows host reproduction in between bouts of castration.

  16. Host genetics and population structure effects on parasitic disease.

    PubMed

    Williams-Blangero, Sarah; Criscione, Charles D; VandeBerg, John L; Correa-Oliveira, Rodrigo; Williams, Kimberly D; Subedi, Janardan; Kent, Jack W; Williams, Jeff; Kumar, Satish; Blangero, John

    2012-03-19

    Host genetic factors exert significant influences on differential susceptibility to many infectious diseases. In addition, population structure of both host and parasite may influence disease distribution patterns. In this study, we assess the effects of population structure on infectious disease in two populations in which host genetic factors influencing susceptibility to parasitic disease have been extensively studied. The first population is the Jirel population of eastern Nepal that has been the subject of research on the determinants of differential susceptibility to soil-transmitted helminth infections. The second group is a Brazilian population residing in an area endemic for Trypanosoma cruzi infection that has been assessed for genetic influences on differential disease progression in Chagas disease. For measures of Ascaris worm burden, within-population host genetic effects are generally more important than host population structure factors in determining patterns of infectious disease. No significant influences of population structure on measures associated with progression of cardiac disease in individuals who were seropositive for T. cruzi infection were found.

  17. Food additives

    PubMed Central

    Spencer, Michael

    1974-01-01

    Food additives are discussed from the food technology point of view. The reasons for their use are summarized: (1) to protect food from chemical and microbiological attack; (2) to even out seasonal supplies; (3) to improve their eating quality; (4) to improve their nutritional value. The various types of food additives are considered, e.g. colours, flavours, emulsifiers, bread and flour additives, preservatives, and nutritional additives. The paper concludes with consideration of those circumstances in which the use of additives is (a) justified and (b) unjustified. PMID:4467857

  18. Liver Fibrosis, Host Genetic and Hepatitis C Virus Related Parameters as Predictive Factors of Response to Therapy against Hepatitis C Virus in HIV/HCV Coinfected Patients

    PubMed Central

    Corchado, Sara; López-Cortés, Luis F.; Rivero-Juárez, Antonio; Torres-Cornejo, Almudena; Rivero, Antonio; Márquez-Coello, Mercedes; Girón-González, José-Antonio

    2014-01-01

    Objective To establish the role of liver fibrosis as a predictive tool of response to pegylated interferon alpha (Peg-IFN) and ribavirin (RBV) treatment in human immunodeficiency (HIV)/hepatitis C virus (HCV) coinfected patients, in addition to recognized predictive factors (HCV load, HCV genotype, IL-28B polymorphism). Patients and Methods A sample of 267 HIV/HCV coinfected patients was treated with Peg-IFN and RBV. Predictive factors of rapid (RVR) and sustained (SVR) virological response were analyzed. Independent variables were age, sex, IL28B, −238 TNF-α and −592 IL-10 polymorphisms, HCV genotype, HCV-RNA levels, significant fibrosis or cirrhosis and CD4+ T cell count. Results Patients infected by HCV genotype 1 (n = 187) showed RVR and SVR in 12% and 39% of cases, respectively. The parameters associated with RVR were IL28B genotype CC and plasma HCV-RNA levels <600000 IU/ml. Advanced liver fibrosis was negatively associated with SVR in patients without RVR. A SVR was obtained in 42% of subjects with HCV genotype 4, and the independent factors associated with SVR were IL28B genotype CC and an HCV-RNA <600000 IU/ml. A SVR was obtained in 66% of patients with HCV genotypes 2/3; in this case, the independent parameter associated with SVR was the absence of significant liver fibrosis. TNF-α and IL-10 polymorphisms were not associated with SVR, although a significantly higher percentage of −238 TNF-α genotype GG was detected in patients with significant liver fibrosis. Conclusions In HIV/HCV coinfected patients with HCV genotypes 1 or 4, RVR, mainly influenced by genotype IL28B and HCV-RNA levels, reliably predicted SVR after 4 weeks of therapy with Peg-IFN plus RBV. In patients infected by HCV genotype 3, an elevated relapse rate compromised the influence of RVR on SVR. Relapses were related to the presence of advanced liver fibrosis. Liver cirrhosis was associated with a −238 TNF-α polymorphism in these patients. PMID:25013899

  19. Temporal Assessment of the Impact of Exposure to Cow Feces inTwo Watersheds by Multiple Host-Specific PCR Assays

    EPA Science Inventory

    Fecal exposure in two watersheds with different management histories was assessed by tracking cattle fecal bacterial populations using multiple host-specific PCR assays. In addition, environmental factors affecting the occurrence of these markers were identified. Each assay was t...

  20. Additive influence of genetic predisposition and conventional risk factors in the incidence of coronary heart disease: a population-based study in Greece

    PubMed Central

    Yiannakouris, Nikos; Katsoulis, Michail; Trichopoulou, Antonia; Ordovas, Jose M; Trichopoulos, Dimitrios

    2014-01-01

    Objectives An additive genetic risk score (GRS) for coronary heart disease (CHD) has previously been associated with incident CHD in the population-based Greek European Prospective Investigation into Cancer and nutrition (EPIC) cohort. In this study, we explore GRS-‘environment’ joint actions on CHD for several conventional cardiovascular risk factors (ConvRFs), including smoking, hypertension, type-2 diabetes mellitus (T2DM), body mass index (BMI), physical activity and adherence to the Mediterranean diet. Design A case–control study. Setting The general Greek population of the EPIC study. Participants and outcome measures 477 patients with medically confirmed incident CHD and 1271 controls participated in this study. We estimated the ORs for CHD by dividing participants at higher or lower GRS and, alternatively, at higher or lower ConvRF, and calculated the relative excess risk due to interaction (RERI) as a measure of deviation from additivity. Results The joint presence of higher GRS and higher risk ConvRF was in all instances associated with an increased risk of CHD, compared with the joint presence of lower GRS and lower risk ConvRF. The OR (95% CI) was 1.7 (1.2 to 2.4) for smoking, 2.7 (1.9 to 3.8) for hypertension, 4.1 (2.8 to 6.1) for T2DM, 1.9 (1.4 to 2.5) for lower physical activity, 2.0 (1.3 to 3.2) for high BMI and 1.5 (1.1 to 2.1) for poor adherence to the Mediterranean diet. In all instances, RERI values were fairly small and not statistically significant, suggesting that the GRS and the ConvRFs do not have effects beyond additivity. Conclusions Genetic predisposition to CHD, operationalised through a multilocus GRS, and ConvRFs have essentially additive effects on CHD risk. PMID:24500614

  1. The Wheat Ethylene Response Factor Transcription Factor PATHOGEN-INDUCED ERF1 Mediates Host Responses to Both the Necrotrophic Pathogen Rhizoctonia cerealis and Freezing Stresses1[C][W][OPEN

    PubMed Central

    Zhu, Xiuliang; Qi, Lin; Liu, Xin; Cai, Shibin; Xu, Huijun; Huang, Rongfeng; Li, Jiarui; Wei, Xuening; Zhang, Zengyan

    2014-01-01

    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

  2. The host immunological response to cancer therapy: An emerging concept in tumor biology

    SciTech Connect

    Voloshin, Tali; Voest, Emile E.; Shaked, Yuval

    2013-07-01

    Almost any type of anti-cancer treatment including chemotherapy, radiation, surgery and targeted drugs can induce host molecular and cellular immunological effects which, in turn, can lead to tumor outgrowth and relapse despite an initial successful therapy outcome. Tumor relapse due to host immunological effects is attributed to angiogenesis, tumor cell dissemination from the primary tumors and seeding at metastatic sites. This short review will describe the types of host cells that participate in this process, the types of factors secreted from the host following therapy that can promote tumor re-growth, and the possible implications of this unique and yet only partially-known process. It is postulated that blocking these specific immunological effects in the reactive host in response to cancer therapy may aid in identifying new host-dependent targets for cancer, which in combination with conventional treatments can prolong therapy efficacy and extend survival. Additional studies investigating this specific research direction—both in preclinical models and in the clinical setting are essential in order to advance our understanding of how tumors relapse and evade therapy. -- Highlights: • Cancer therapy induces host molecular and cellular pro-tumorigenic effects. • Host effects in response to therapy may promote tumor relapse and metastasis. • The reactive host consists of immunological mediators promoting tumor re-growth. • Blocking therapy-induced host mediators may improve outcome.

  3. Stretching human mesenchymal stromal cells on stiffness-customized collagen type I generates a smooth muscle marker profile without growth factor addition

    PubMed Central

    Rothdiener, Miriam; Hegemann, Miriam; Uynuk-Ool, Tatiana; Walters, Brandan; Papugy, Piruntha; Nguyen, Phong; Claus, Valentin; Seeger, Tanja; Stoeckle, Ulrich; Boehme, Karen A.; Aicher, Wilhelm K.; Stegemann, Jan P.; Hart, Melanie L.; Kurz, Bodo; Klein, Gerd; Rolauffs, Bernd

    2016-01-01

    Using matrix elasticity and cyclic stretch have been investigated for inducing mesenchymal stromal cell (MSC) differentiation towards the smooth muscle cell (SMC) lineage but not in combination. We hypothesized that combining lineage-specific stiffness with cyclic stretch would result in a significantly increased expression of SMC markers, compared to non-stretched controls. First, we generated dense collagen type I sheets by mechanically compressing collagen hydrogels. Atomic force microscopy revealed a nanoscale stiffness range known to support myogenic differentiation. Further characterization revealed viscoelasticity and stable biomechanical properties under cyclic stretch with >99% viable adherent human MSC. MSCs on collagen sheets demonstrated a significantly increased mRNA but not protein expression of SMC markers, compared to on culture flasks. However, cyclic stretch of MSCs on collagen sheets significantly increased both mRNA and protein expression of α-smooth muscle actin, transgelin, and calponin versus plastic and non-stretched sheets. Thus, lineage-specific stiffness and cyclic stretch can be applied together for inducing MSC differentiation towards SMCs without the addition of recombinant growth factors or other soluble factors. This represents a novel stimulation method for modulating the phenotype of MSCs towards SMCs that could easily be incorporated into currently available methodologies to obtain a more targeted control of MSC phenotype. PMID:27775041

  4. Short-term salivary acetaldehyde increase due to direct exposure to alcoholic beverages as an additional cancer risk factor beyond ethanol metabolism

    PubMed Central

    2011-01-01

    Background An increasing body of evidence now implicates acetaldehyde as a major underlying factor for the carcinogenicity of alcoholic beverages and especially for oesophageal and oral cancer. Acetaldehyde associated with alcohol consumption is regarded as 'carcinogenic to humans' (IARC Group 1), with sufficient evidence available for the oesophagus, head and neck as sites of carcinogenicity. At present, research into the mechanistic aspects of acetaldehyde-related oral cancer has been focused on salivary acetaldehyde that is formed either from ethanol metabolism in the epithelia or from microbial oxidation of ethanol by the oral microflora. This study was conducted to evaluate the role of the acetaldehyde that is found as a component of alcoholic beverages as an additional factor in the aetiology of oral cancer. Methods Salivary acetaldehyde levels were determined in the context of sensory analysis of different alcoholic beverages (beer, cider, wine, sherry, vodka, calvados, grape marc spirit, tequila, cherry spirit), without swallowing, to exclude systemic ethanol metabolism. Results The rinsing of the mouth for 30 seconds with an alcoholic beverage is able to increase salivary acetaldehyde above levels previously judged to be carcinogenic in vitro, with levels up to 1000 μM in cases of beverages with extreme acetaldehyde content. In general, the highest salivary acetaldehyde concentration was found in all cases in the saliva 30 sec after using the beverages (average 353 μM). The average concentration then decreased at the 2-min (156 μM), 5-min (76 μM) and 10-min (40 μM) sampling points. The salivary acetaldehyde concentration depends primarily on the direct ingestion of acetaldehyde contained in the beverages at the 30-sec sampling, while the influence of the metabolic formation from ethanol becomes the major factor at the 2-min sampling point. Conclusions This study offers a plausible mechanism to explain the increased risk for oral cancer associated with

  5. Changes in diet, cardiovascular risk factors and modelled cardiovascular risk following diagnosis of diabetes: 1-year results from the ADDITION-Cambridge trial cohort

    PubMed Central

    Savory, L A; Griffin, S J; Williams, K M; Prevost, A T; Kinmonth, A-L; Wareham, N J; Simmons, R K

    2014-01-01

    Aims To describe change in self-reported diet and plasma vitamin C, and to examine associations between change in diet and cardiovascular disease risk factors and modelled 10-year cardiovascular disease risk in the year following diagnosis of Type 2 diabetes. Methods Eight hundred and sixty-seven individuals with screen-detected diabetes underwent assessment of self-reported diet, plasma vitamin C, cardiovascular disease risk factors and modelled cardiovascular disease risk at baseline and 1 year (n = 736) in the ADDITION-Cambridge trial. Multivariable linear regression was used to quantify the association between change in diet and cardiovascular disease risk at 1 year, adjusting for change in physical activity and cardio-protective medication. Results Participants reported significant reductions in energy, fat and sodium intake, and increases in fruit, vegetable and fibre intake over 1 year. The reduction in energy was equivalent to an average-sized chocolate bar; the increase in fruit was equal to one plum per day. There was a small increase in plasma vitamin C levels. Increases in fruit intake and plasma vitamin C were associated with small reductions in anthropometric and metabolic risk factors. Increased vegetable intake was associated with an increase in BMI and waist circumference. Reductions in fat, energy and sodium intake were associated with reduction in HbA1c, waist circumference and total cholesterol/modelled cardiovascular disease risk, respectively. Conclusions Improvements in dietary behaviour in this screen-detected population were associated with small reductions in cardiovascular disease risk, independently of change in cardio-protective medication and physical activity. Dietary change may have a role to play in the reduction of cardiovascular disease risk following diagnosis of diabetes. PMID:24102972

  6. A Risk Score with Additional Four Independent Factors to Predict the Incidence and Recovery from Metabolic Syndrome: Development and Validation in Large Japanese Cohorts

    PubMed Central

    Obokata, Masaru; Negishi, Kazuaki; Ohyama, Yoshiaki; Okada, Haruka; Imai, Kunihiko; Kurabayashi, Masahiko

    2015-01-01

    Background Although many risk factors for Metabolic syndrome (MetS) have been reported, there is no clinical score that predicts its incidence. The purposes of this study were to create and validate a risk score for predicting both incidence and recovery from MetS in a large cohort. Methods Subjects without MetS at enrollment (n = 13,634) were randomly divided into 2 groups and followed to record incidence of MetS. We also examined recovery from it in rest 2,743 individuals with prevalent MetS. Results During median follow-up of 3.0 years, 878 subjects in the derivation and 757 in validation cohorts developed MetS. Multiple logistic regression analysis identified 12 independent variables from the derivation cohort and initial score for subsequent MetS was created, which showed good discrimination both in the derivation (c-statistics 0.82) and validation cohorts (0.83). The predictability of the initial score for recovery from MetS was tested in the 2,743 MetS population (906 subjects recovered from MetS), where nine variables (including age, sex, γ-glutamyl transpeptidase, uric acid and five MetS diagnostic criteria constituents.) remained significant. Then, the final score was created using the nine variables. This score significantly predicted both the recovery from MetS (c-statistics 0.70, p<0.001, 78% sensitivity and 54% specificity) and incident MetS (c-statistics 0.80) with an incremental discriminative ability over the model derived from five factors used in the diagnosis of MetS (continuous net reclassification improvement: 0.35, p < 0.001 and integrated discrimination improvement: 0.01, p<0.001). Conclusions We identified four additional independent risk factors associated with subsequent MetS, developed and validated a risk score to predict both incident and recovery from MetS. PMID:26230621

  7. Identification and characterization of transforming growth factor β-activated kinase 1 from Litopenaeus vannamei involved in anti-bacterial host defense.

    PubMed

    Wang, Sheng; Li, Haoyang; Lǚ, Kai; Qian, Zhe; Weng, Shaoping; He, Jianguo; Li, Chaozheng

    2016-05-01

    LvTAK1, a member of transforming growth factor β-activated kinase 1 (TAK1) families, has been identified from Litopenaeus vannamei in this study. The full length of LvTAK1 is 2670 bp, including a 2277 bp open reading frame (ORF) that encoded a putative protein of 758 amino acids with a calculated molecular weight of ∼83.4 kDa LvTAK1 expression was most abundant in muscles and was up-regulated in gills after LPS, Vibrio parahaemolyticus, Staphylococcus aureus, Poly (I:C) and WSSV challenge. Both in vivo and in vitro experiments indicated that LvTAK1 could activate the expression of several antimicrobial peptide genes (AMPs). In addition, the dsRNA-mediated knockdown of LvTAK1 enhanced the susceptibility of shrimps to Vibrio parahaemolyticus, a kind of Gram-negative bacteria. These results suggested LvTAK1 played important roles in anti-bacterial infection. CoIP and subcellular localization assay demonstrated that LvTAK1 could interact with its binding protein LvTAB2, a key component of IMD pathway. Moreover, over-expression of LvTAK1 in Drosophila S2 cell could strongly induce the promoter activity of Diptericin (Dpt), a typical AMP which is used to read out of the activation of IMD pathway. These findings suggested that LvTAK1 could function as a component of IMD pathway. Interestingly, with the over-expression of LvTAK1 in S2 cell, the promoter activity of Metchnikowin (Mtk), a main target gene of Toll/Dif pathway, was up-regulated over 30 times, suggesting that LvTAK1 may also take part in signal transduction of the Toll pathway. In conclusion, we provided some evidences that the involvement of LvTAK1 in the regulation of both Toll and IMD pathways, as well as innate immune against bacterial infection in shrimp.

  8. Molecular phylogenies reveal host-specific divergence of Ophiocordyceps unilateralis sensu lato following its host ants.

    PubMed

    Kobmoo, N; Mongkolsamrit, S; Tasanathai, K; Thanakitpipattana, D; Luangsa-Ard, J J

    2012-06-01

    Ophiocordyceps unilateralis (Hypocreales, Ascomycetes) is an entomopathogenic fungus specific to formicine ants (Formicinae, Hymenoptera). Previous works have shown that the carpenter ant Camponotus leonardi acts as the principal host with occasional infections of ants from the genus Polyrhachis (sister genus of Camponotus). Observations were made on the permanent plots of Mo Singto, Khao Yai National Park of Thailand according to which O. unilateralis was found to occur predominantly on three host species: C. leonardi, C. saundersi and P. furcata. Molecular phylogenies of the elongation factor 1-α and β-Tubulin genes indicate a separation of O. unilateralis samples into three clades, reflecting specificity to each of the three different ant species. Samples collected from P. furcata and from C. leonardi were found to form sister groups with samples from C. saundersi forming an outgroup to the latter. Additional samples collected from unidentified ant species of Camponotus and Polyrhachis were positioned as outgroups to those samples on identified species. These results demonstrate that O. unilateralis is clearly not a single phylogenetic species and comprises at least three species that are specific to different host ant species. These cryptic species may arise through recent events of speciation driven by their specificity to host ant species.

  9. Molecular phylogenies reveal host-specific divergence of Ophiocordyceps unilateralis sensu lato following its host ants.

    PubMed

    Kobmoo, N; Mongkolsamrit, S; Tasanathai, K; Thanakitpipattana, D; Luangsa-Ard, J J

    2012-06-01

    Ophiocordyceps unilateralis (Hypocreales, Ascomycetes) is an entomopathogenic fungus specific to formicine ants (Formicinae, Hymenoptera). Previous works have shown that the carpenter ant Camponotus leonardi acts as the principal host with occasional infections of ants from the genus Polyrhachis (sister genus of Camponotus). Observations were made on the permanent plots of Mo Singto, Khao Yai National Park of Thailand according to which O. unilateralis was found to occur predominantly on three host species: C. leonardi, C. saundersi and P. furcata. Molecular phylogenies of the elongation factor 1-α and β-Tubulin genes indicate a separation of O. unilateralis samples into three clades, reflecting specificity to each of the three different ant species. Samples collected from P. furcata and from C. leonardi were found to form sister groups with samples from C. saundersi forming an outgroup to the latter. Additional samples collected from unidentified ant species of Camponotus and Polyrhachis were positioned as outgroups to those samples on identified species. These results demonstrate that O. unilateralis is clearly not a single phylogenetic species and comprises at least three species that are specific to different host ant species. These cryptic species may arise through recent events of speciation driven by their specificity to host ant species. PMID:22494010

  10. Genetic architecture underlying host choice differentiation in the sympatric host races of Lochmaea capreae leaf beetles.

    PubMed

    Soudi, Shaghayegh; Reinhold, Klaus; Engqvist, Leif

    2016-04-01

    Speciation in herbivorous insects has received considerable attention during the last few decades. Much of this group's diversity originates from adaptive population divergence onto different host plants, which often involves the evolution of specialized patterns of host choice behaviour. Differences in host choice often translates directly into divergence in mating sites, and therefore positive assortative mating will be created which will act as a strong barrier to gene flow. In this study, we first explored whether host choice is a genetically determined trait in the sympatric willow and birch host races of the leaf feeding beetle Lochmaea capreae, or whether larval experience influences adult host choice. Once we had established that host choice is a genetically based trait we determined its genetic architecture. To achieve this, we employed a reciprocal transplant design in which offspring from pure willow and birch cross-types, F1, F2 and backcrosses were raised on each host plant and their preference was determined upon reaching adulthood. We then applied joint-scaling analysis to uncover the genetic architecture of host preference. Our results suggest that rearing host does not have a pronounced effect on adult's host choice; rather the segregation pattern implies the existence of genetic loci affecting host choice in these host races. The joint-scaling analysis revealed that population differences in host choice are mainly influenced by the contribution of additive genetic effects and also maternally inherited cytoplasmic effects. We explore the implications of our findings for evolutionary dynamics of sympatric host race formation and speciation.

  11. HIV-Host Interactions: Implications for Vaccine Design

    PubMed Central

    Haynes, Barton F.; Shaw, George M.; Korber, Bette; Kelsoe, Garnett; Sodroski, Joseph; Hahn, Beatrice H.; Borrow, Persephone; McMichael, Andrew J.

    2016-01-01

    Summary Development of an effective AIDS vaccine is a global priority. However, the extreme diversity of human immunodeficiency virus type 1 (HIV-1), which is a consequence of its propensity to mutate to escape immune responses, along with host factors that prevent the elicitation of protective immune responses, continue to hinder vaccine development. Breakthroughs in understanding of the biology of the transmitted virus, the structure and nature of its envelope trimer, vaccine-induced CD8 T cell control in primates, and host control of broadly neutralizing antibody elicitation have given rise to new vaccine strategies. Despite this promise, emerging data from preclinical trials reinforce the need for gaining additional insight into virus – host biology in order to facilitate the development of a successful vaccine. PMID:26922989

  12. Macrophage Migration Inhibitory Factor (MIF) of the protozoan parasite Eimeria influences the components of the immune system of its host, the chicken

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Macrophage migration inhibitory factor (MIF) is a soluble factor produced by sensitized T lymphocytes that inhibits the random migration of macrophages. Homologues of MIF from invertebrates have been identified making it an interesting molecule from a functional perspective. In the present study, ...

  13. Fat and starch as additive risk factors for milk fat depression in dairy diets containing corn dried distillers grains with solubles.

    PubMed

    Ramirez Ramirez, H A; Castillo Lopez, E; Harvatine, K J; Kononoff, P J

    2015-03-01

    Two experiments were conducted to evaluate the additive effects of starch and fat as risk factors associated with milk fat depression in dairy diets containing corn dried distillers grains with solubles. In experiment 1, 4 multiparous ruminally cannulated Holstein cows, averaging 114±14 d in milk and 662±52 kg of body weight, were randomly assigned to 4 treatments in a 4×4 Latin square to determine the effect of these risk factors on rumen fermentation and milk fatty acid profile. In each 21-d period, cows were assigned to 1 of 4 dietary treatments: a control diet (CON; ether extract 5.2%, starch 19%); CON with added oil (OL; ether extract 6.4%, starch 18%); CON with added starch (STR; ether extract 5.5%, starch 22%); and CON with added oil and starch (COMBO; ether extract 6.5%, starch 23%). After completion of experiment 1, milk production response was evaluated in a second experiment with a similar approach to diet formulation. Twenty Holstein cows, 12 primiparous and 8 multiparous, averaging 117±17 d in milk and 641±82 kg, were used in replicated 4×4 Latin squares with 21-d periods. Results from experiment 1 showed that ruminal pH was not affected by treatment averaging 5.87±0.08. Molar proportion of propionate in rumen fluid was greatest on the COMBO diet, followed by OL and STR, and lowest for CON. The concentration of trans-10,cis-12 conjugated linoleic acid in milk fat increased with the COMBO diet. Adding oil, starch, or a combination of both resulted in lower concentration and yield of fatty acids<16 carbons. Compared with the control, OL and STR resulted in 13% lower concentration, whereas the COMBO diet resulted in a 27% reduction; similarly yield was reduced by 24% with the OL and STR treatments and 54% with the COMBO diet. In experiment 2, milk yield, milk protein percentage, and milk protein yield were similar across treatments, averaging 26.6±1.01 kg/d, 3.2±0.05%, and 0.84±0.03 kg/d, respectively. Fat-corrected milk was greatest for CON, 26

  14. Dynamics of host plant use and species diversity in Polygonia butterflies (Nymphalidae).

    PubMed

    Weingartner, E; Wahlberg, N; Nylin, S

    2006-03-01

    The ability of insects to utilize different host plants has been suggested to be a dynamic and transient phase. During or after this phase, species can shift to novel host plants or respecialize on ancestral ones. Expanding the range of host plants might also be a factor leading to higher levels of net speciation rates. In this paper, we have studied the possible importance of host plant range for diversification in the genus Polygonia (Nymphalidae, Nymphalini). We have compared species richness between sistergroups in order to find out if there are any differences in number of species between clades including species that utilize only the ancestral