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Sample records for antibacterial host defense

  1. A unique host defense pathway: TRIF mediates both antiviral and antibacterial immune responses

    OpenAIRE

    Hyun, Jinhee; Kanagavelu, Saravana; Fukata, Masayuki

    2012-01-01

    Both anti-viral and anti-bacterial host defense mechanisms involve TRIF signaling. TRIF provides early clearance of pathogens and coordination of a local inflammatory ensemble through an interferon cascade, while it may trigger organ damage. The multipotentiality of TRIF-mediated immune machinery may direct the fate of our continuous battle with microbes.

  2. A miniature mimic of host defense peptides with systemic antibacterial efficacy

    International Nuclear Information System (INIS)

    Oligomers of acylated lysines (OAKs) are synthetic mimics of host defense peptides (HDPs) with promising antimicrobial properties. Here we challenged the OAK concept for its ability to generate both systemically efficient and economically viable lead compounds for fighting multidrug-resistant bacteria. We describe the design and characterization of a miniature OAK composed of only 3 lysyls and 2 acyls (designated C12(ω7)K-β12) that preferentially targets gram-positive species by a bacteriostatic mode of action. To gain insight into the mechanism of action, we examined the interaction of OAK with various potential targets, including phospholipid bilayers, using surface plasmon resonance, and Langmuir monolayers, using insertion assays, epifluorescence microscopy, and grazing incidence X-ray diffraction, in a complementary manner. Collectively, the data support the notion that C12(ω7)K-β12 damages the plasma-membrane architecture similarly to HDPs, that is, following a near-classic 2-step interaction including high-affinity electrostatic adhesion and a subsequent shallow insertion that was limited to the phospholipid head group region. Notably, preliminary acute toxicity and efficacy studies performed with mouse models of infection have consolidated the potential of OAK for treating bacterial infections, including systemic treatments of methicillin-resistant Staphylococcus aureus. Such simple yet robust chemicals might be useful for various antibacterial applications while circumventing potential adverse effects associated with cytolytic compounds.

  3. Budesonide suppresses pulmonary antibacterial host defense by down-regulating cathelicidin-related antimicrobial peptide in allergic inflammation mice and in lung epithelial cells

    Directory of Open Access Journals (Sweden)

    Wang Peng

    2013-02-01

    Full Text Available Abstract Background Glucocorticoids are widely regarded as the most effective treatment for asthma. However, the direct impact of glucocorticoids on the innate immune system and antibacterial host defense during asthma remain unclear. Understanding the mechanisms underlying this process is critical to the clinical application of glucocorticoids for asthma therapy. After sensitization and challenge with ovalbumin (OVA, BALB/c mice were treated with inhaled budesonide and infected with Pseudomonas aeruginosa (P. aeruginosa. The number of viable bacteria in enflamed lungs was evaluated, and levels of interleukin-4 (IL-4 and interferon-γ (IFN-γ in serum were measured. A lung epithelial cell line was pretreated with budesonide. Levels of cathelicidin-related antimicrobial peptide (CRAMP were measured by immunohistochemistry and western blot analysis. Intracellular bacteria were observed in lung epithelial cells. Results Inhaled budesonide enhanced lung infection in allergic mice exposed to P. aeruginosa and increased the number of viable bacteria in lung tissue. Higher levels of IL-4 and lower levels of IFN-γ were observed in the serum. Budesonide decreased the expression of CRAMP, increased the number of internalized P. aeruginosa in OVA-challenged mice and in lung epithelial cell lines. These data indicate that inhaled budesonide can suppress pulmonary antibacterial host defense by down-regulating CRAMP in allergic inflammation mice and in cells in vitro. Conclusions Inhaled budesonide suppressed pulmonary antibacterial host defense in an asthmatic mouse model and in lung epithelium cells in vitro. This effect was dependent on the down-regulation of CRAMP.

  4. The Inflammasome in Host Defense

    Directory of Open Access Journals (Sweden)

    Gang Chen

    2009-12-01

    Full Text Available Nod-like receptors have emerged as an important family of sensors in host defense. These receptors are expressed in macrophages, dendritic cells and monocytes and play an important role in microbial immunity. Some Nod-like receptors form the inflammasome, a protein complex that activates caspase-1 in response to several stimuli. Caspase-1 activation leads to processing and secretion of pro-inflammatory cytokines such as interleukin (IL-1β and IL-18. Here, we discuss recent advances in the inflammasome field with an emphasis on host defense. We also compare differential requirements for inflammasome activation in dendritic cells, macrophages and monocytes.

  5. A Diverse Family of Host-Defense Peptides (Piscidins) Exhibit Specialized Anti-Bacterial and Anti-Protozoal Activities in Fishes.

    Science.gov (United States)

    Salger, Scott A; Cassady, Katherine R; Reading, Benjamin J; Noga, Edward J

    2016-01-01

    Conventional antibiotics and other chemical-based drugs are currently one of the most common methods used to control disease-related mortality in animal agriculture. Use of the innate immune system to decrease disease related mortalities is a novel alternative to conventional drugs. One component of the innate immune system is the host-defense peptides, also known as antimicrobial peptides. Host-defense peptides are typically small, amphipathic, α-helical peptides with a broad-spectrum of action against viral, bacterial, fungal, and/or protozoal pathogens. Piscidins are host-defense peptides first discovered in the hybrid striped bass (white bass, Morone chrysops, x striped bass, M. saxatilis). In this paper we identify four new piscidin isoforms in the hybrid striped bass and describe their tissue distributions. We also determine the progenitor species of origin of each piscidin (orthology) and propose a revised nomenclature for this newly described piscidin family based on a three class system. The Class I piscidins (22 amino acids in length; striped bass and white bass piscidin 1 and piscidin 3) show broad-spectrum activity against bacteria and ciliated protozoans, while the Class III piscidins (55 amino acids in length; striped bass and white bass piscidin 6 and striped bass piscidin 7) primarily show anti-protozoal activity. The Class II piscidins (44-46 amino acids in length; striped bass and white bass piscidin 4 and white bass piscidin 5) have a level of activity against bacteria and protozoans intermediate to Classes I and III. Knowledge of piscidin function and activity may help in the future development of disease-resistant lines of striped bass and white bass that could be used to produce superior hybrids for aquaculture. PMID:27552222

  6. Carp erythrodermatitis: host defense-pathogen interaction.

    OpenAIRE

    Pourreau, C.N.

    1990-01-01

    The outcome of a bacterial infection depends on the interaction between pathogen and host. The ability of the microbe to survive in the host depends on its invasive potential (i.e. spreading and multiplication), and its ability to obtain essential nutrients and to resist the host's defense system. On the other hand, the host's resistance to a bacterial attack depends on its physiological state, the intensity of the bacterial attack and the efficacy of the defense system to neutralize toxins a...

  7. Carp erythrodermatitis: host defense-pathogen interaction.

    NARCIS (Netherlands)

    Pourreau, C.N.

    1990-01-01

    The outcome of a bacterial infection depends on the interaction between pathogen and host. The ability of the microbe to survive in the host depends on its invasive potential (i.e. spreading and multiplication), and its ability to obtain essential nutrients and to resist the host's defense syste

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

    Science.gov (United States)

    Wang, Sheng; Li, Haoyang; L, 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, Staphhylococcu saureus, 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. PMID:27033469

  9. Revisiting Caspase-11 Function in Host Defense

    OpenAIRE

    Ng, Tessie M.; Monack, Denise M.

    2013-01-01

    Pro-inflammatory caspases play important roles in innate immunity. Much attention has focused on caspase-1, which acts to eliminate pathogens by obliterating their replicative niches as well as alerting the host to their presence. Emerging data now sheds light on the lesser-studied pro-inflammatory caspase-11 in the combat between host and pathogen. With new tools available, researchers are now further elucidating the mechanisms by which caspase-11 contributes to host defense. Here, we review...

  10. GENETIC BASIS OF MURINE ANTIBACTERIAL DEFENSE TO STREPTOCOCCAL LUNG INFECTION

    Science.gov (United States)

    To evaluate the effect of genetic background and toll-like receptor 2 on antibacterial defense to streptococcal infection, eight genetically diverse strains of mice (A/J, DBA/2J, CAST/Ei, FVB/NJ, BALB/cJ, C57BL/6J, 129/SvImJ, and C3H/HeJ) and tlr2-deficient mice (C57BL/6

  11. Hepcidin and Host Defense against Infectious Diseases

    OpenAIRE

    Michels, Kathryn; Nemeth, Elizabeta; Ganz, Tomas; Mehrad, Borna

    2015-01-01

    Hepcidin is the master regulator of iron homeostasis in vertebrates. The synthesis of hepcidin is induced by systemic iron levels and by inflammatory stimuli. While the role of hepcidin in iron regulation is well established, its contribution to host defense is emerging as complex and multifaceted. In this review, we summarize the literature on the role of hepcidin as a mediator of antimicrobial immunity. Hepcidin induction during infection causes depletion of extracellular iron, which is tho...

  12. Avian Antimicrobial Host Defense Peptides: From Biology to Therapeutic Applications

    Directory of Open Access Journals (Sweden)

    Guolong Zhang

    2014-02-01

    Full Text Available Host defense peptides (HDPs are an important first line of defense with antimicrobial and immunomoduatory properties. Because they act on the microbial membranes or host immune cells, HDPs pose a low risk of triggering microbial resistance and therefore, are being actively investigated as a novel class of antimicrobials and vaccine adjuvants. Cathelicidins and β-defensins are two major families of HDPs in avian species. More than a dozen HDPs exist in birds, with the genes in each HDP family clustered in a single chromosomal segment, apparently as a result of gene duplication and diversification. In contrast to their mammalian counterparts that adopt various spatial conformations, mature avian cathelicidins are mostly α-helical. Avian β-defensins, on the other hand, adopt triple-stranded β-sheet structures similar to their mammalian relatives. Besides classical β-defensins, a group of avian-specific β-defensin-related peptides, namely ovodefensins, exist with a different six-cysteine motif. Like their mammalian counterparts, avian cathelicidins and defensins are derived from either myeloid or epithelial origin expressed in a majority of tissues with broad-spectrum antibacterial and immune regulatory activities. Structure-function relationship studies with several avian HDPs have led to identification of the peptide analogs with potential for use as antimicrobials and vaccine adjuvants. Dietary modulation of endogenous HDP synthesis has also emerged as a promising alternative approach to disease control and prevention in chickens.

  13. Avian antimicrobial host defense peptides: from biology to therapeutic applications.

    Science.gov (United States)

    Zhang, Guolong; Sunkara, Lakshmi T

    2014-01-01

    Host defense peptides (HDPs) are an important first line of defense with antimicrobial and immunomoduatory properties. Because they act on the microbial membranes or host immune cells, HDPs pose a low risk of triggering microbial resistance and therefore, are being actively investigated as a novel class of antimicrobials and vaccine adjuvants. Cathelicidins and β-defensins are two major families of HDPs in avian species. More than a dozen HDPs exist in birds, with the genes in each HDP family clustered in a single chromosomal segment, apparently as a result of gene duplication and diversification. In contrast to their mammalian counterparts that adopt various spatial conformations, mature avian cathelicidins are mostly α-helical. Avian β-defensins, on the other hand, adopt triple-stranded β-sheet structures similar to their mammalian relatives. Besides classical β-defensins, a group of avian-specific β-defensin-related peptides, namely ovodefensins, exist with a different six-cysteine motif. Like their mammalian counterparts, avian cathelicidins and defensins are derived from either myeloid or epithelial origin expressed in a majority of tissues with broad-spectrum antibacterial and immune regulatory activities. Structure-function relationship studies with several avian HDPs have led to identification of the peptide analogs with potential for use as antimicrobials and vaccine adjuvants. Dietary modulation of endogenous HDP synthesis has also emerged as a promising alternative approach to disease control and prevention in chickens. PMID:24583933

  14. Molecular mechanisms of epithelial host defense in the airways

    OpenAIRE

    Vos, Joost Bastiaan

    2007-01-01

    Airway epithelial cells are indispensable for the host defense system in the lungs. Various strategies by which epithelial cells protect the lungs against inhaled pathogens have been described. In spite of that, the molecular mechanisms by which epithelial cells initiate and control the host defense response have not been explored systematically. In this thesis, the molecular mechanisms underlying the initiation and regulation of the early epithelial host defense response in the airways were ...

  15. Oncolytic Activities of Host Defense Peptides

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    Lars Steinstraesser

    2011-11-01

    Full Text Available Cancer continues to be a leading source of morbidity and mortality worldwide in spite of progress in oncolytic therapies. In addition, the incidence of cancers affecting the breast, kidney, prostate and skin among others continue to rise. Chemotherapeutic drugs are widely used in cancer treatment but have the serious drawback of nonspecific toxicity because these agents target any rapidly dividing cell without discriminating between healthy and malignant cells. In addition, many neoplasms eventually become resistant to conventional chemotherapy due to selection for multidrug-resistant variants. The limitations associated with existing chemotherapeutic drugs have stimulated the search for new oncolytic therapies. Host defense peptides (HDPs may represent a novel family of oncolytic agents that can avoid the shortcomings of conventional chemotherapy because they exhibit selective cytotoxicity against a broad spectrum of malignant human cells, including multi-drug-resistant neoplastic cells. Oncolytic activity by HDPs is usually via necrosis due to cell membrane lysis, but some HDPs can trigger apoptosis in cancer cells via mitochondrial membrane disruption. In addition, certain HDPs are anti-angiogenic which may inhibit cancer progression. This paper reviews oncolytic HDP studies in order to address the suitability of selected HDPs as oncolytic therapies.

  16. Host defense and hepatic metallothionein induction

    International Nuclear Information System (INIS)

    This is a brief review of my investigations to search a mechanism of the promotion of radioresistance in mice regarding the activation of host defense mechanism which seems to involve chemical as well as immunological protections. Intraperitoneal (i.p.) injection of a metal salt: MnCl2 (10mg Mn/kg) or of a biological response modifier (BRM): IL-1 (40 μg/kg) or OK432 (15mg/kg), or Chinese herbal medicine, Toki (270mg/kg) or Shigoka (250mg/kg), one day prior to 7.5 Gy of X-ray irradiation produced prominent radioprotection in mice. While i.p. injection of MgCl2 (10mg/kg), or PS-K (50mg/kg) or Lentinan (5mg/kg) showed none. The obtained dose reduction factor (DRF) was 1.2 - 1.3. Pretreated mice in which more than 4 or 5 times of hepatic metallothionein (MT) synthesis of the control level was observed showed prominent radioresistance, while pretreated mice in which hepatic MT induction was less than 3 times of the control showed no promotion of radioresistance. The administration of MnCl2, CdCl2, OK432 or Toki as well as skin excision, caused enhancement in superoxide anion production (SOA) in peripheral leukocytes measured by chemiluminescence response, which was due to an increase in the number of polymorphonuclear leukocytes (PMN). The increase in SOA in peripheral leukocytes and hepatic MT synthesis occurred almost concomitantly. The degree of radioresistance was also consistent with peripheral blood corpuscle counts measured on the 10th and 15th postirradiation days. We, therefore, speculate that the enhancement of radioresistance by the preirradiation treatment with a certain metal and/or BRM or stressful load might be established by a coordinating promotion between chemical and immunological protection mechanisms. (author)

  17. Host defense reinforces host–parasite cospeciation

    OpenAIRE

    Clayton, Dale H.; Bush, Sarah E.; Goates, Brad M.; Johnson, Kevin P.

    2003-01-01

    Cospeciation occurs when interacting groups, such as hosts and parasites, speciate in tandem, generating congruent phylogenies. Cospeciation can be a neutral process in which parasites speciate merely because they are isolated on diverging host islands. Adaptive evolution may also play a role, but this has seldom been tested. We explored the adaptive basis of cospeciation by using a model system consisting of feather lice (Columbicola) and their pigeon and dove hosts (Columbiformes). We recon...

  18. Interleukin 17-mediated host defense against candida albicans

    OpenAIRE

    Sparber, Florian; LeibundGut-Landmann, Salomé

    2015-01-01

    Candida albicans is part of the normal microbiota in most healthy individuals. However, it can cause opportunistic infections if host defenses are breached, with symptoms ranging from superficial lesions to severe systemic disease. The study of rare congenital defects in patients with chronic mucocutaneous candidiasis led to the identification of interleukin-17 (IL-17) as a key factor in host defense against mucosal fungal infection. Experimental infections in mice confirmed the critical role...

  19. Interleukin 17-Mediated Host Defense against Candida albicans

    OpenAIRE

    Florian Sparber; Salomé LeibundGut-Landmann

    2015-01-01

    Candida albicans is part of the normal microbiota in most healthy individuals. However, it can cause opportunistic infections if host defenses are breached, with symptoms ranging from superficial lesions to severe systemic disease. The study of rare congenital defects in patients with chronic mucocutaneous candidiasis led to the identification of interleukin-17 (IL-17) as a key factor in host defense against mucosal fungal infection. Experimental infections in mice confirmed the critical role...

  20. Pattern Recognition Receptors in Innate Immunity, Host Defense, and Immunopathology

    Science.gov (United States)

    Suresh, Rahul; Mosser, David M.

    2013-01-01

    Infection by pathogenic microbes initiates a set of complex interactions between the pathogen and the host mediated by pattern recognition receptors. Innate immune responses play direct roles in host defense during the early stages of infection, and they also exert a profound influence on the generation of the adaptive immune responses that ensue.…

  1. Antibacterial properties of contact defensive secretions in neotropical Crematogaster ants

    Directory of Open Access Journals (Sweden)

    Y Quinet

    2012-01-01

    Full Text Available Crematogaster ants use their contact venoms to compete with other ants. Although those venoms are used primarily as repellent and toxic secretions, they may have other functions. The present study aimed to test the antibacterial property of abdominal venom of three neotropical Crematogaster ant species (C. distans, C. pygmaea and C. rochai against gram-negative (Escherichia coli and Pseudomonas aeruginosa and gram-positive (Enterococcus faecalis and Staphylococcus aureus bacteria. Sterile filter paper was soaked with C. distans, C. pygmaea or C. rochai crude venom and placed on an agar dish that was inoculated with bacterial suspensions. The agar dish was incubated overnight at 37ºC and examined for zones of growth inhibition. For each tested venom and bacterial strain, three venom concentrations were used, with six replicates for each concentration: 1, 2 and 4 DGE (Dufour's gland equivalent. The venom of C. pygmaea, but not those of C. rochai and C. distans, inhibited the growth of all tested gram-positive and gram-negative bacterial strains. This is the first evidence of antibacterial properties of contact venoms in Crematogaster ants and it supports the claim that ant venoms are multifunctional. It is hypothesized that only C. pygmaea venom showed antibacterial activities due to its nesting habits.

  2. Crossing the Rubicon: New Roads Lead to Host Defense

    OpenAIRE

    Bradfield, Clinton J.; Kim, Bae-Hoon; MacMicking, John D.

    2012-01-01

    Rubicon is a protein known to engage the Beclin-1/Vps34-PI3K/UVRAG complex and inhibit endosome and autophagosomal fusion with lysosomes. Yang et al. (2012) uncover new roles for this adaptor protein within noncanonical p22phox or CARD9 complexes that regulate oxidative and cytokine responses in activated macrophages, respectively. Both complexes impact pathogen-specific host defense.

  3. Toll-Like Receptor Initiated Host Defense against Toxoplasma gondii

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    Eric Y. Denkers

    2010-01-01

    Full Text Available Toxoplasma gondii is an intracellular pathogen notable for its ability to establish a stable host-parasite relationship amongst a wide range of host species and in a large percentage of the human population. Toll-like receptor signaling through MyD88 is a critical pathway in initiating defense against this opportunistic protozoan and may also be a mediator of pathology during immune dysfunction. Other MyD88 independent signaling pathways are also involved in the host-parasite interaction. These responses can be triggered by the parasite itself, but interactions with the intestinal microbiota add additional complexity during enteric infection.

  4. Interleukin 17-Mediated Host Defense against Candida albicans

    Directory of Open Access Journals (Sweden)

    Florian Sparber

    2015-08-01

    Full Text Available Candida albicans is part of the normal microbiota in most healthy individuals. However, it can cause opportunistic infections if host defenses are breached, with symptoms ranging from superficial lesions to severe systemic disease. The study of rare congenital defects in patients with chronic mucocutaneous candidiasis led to the identification of interleukin-17 (IL-17 as a key factor in host defense against mucosal fungal infection. Experimental infections in mice confirmed the critical role of IL-17 in mucocutaneous immunity against C. albicans. Research on mouse models has also contributed importantly to our current understanding of the regulation of IL-17 production by different cellular sources and its effector functions in distinct tissues. In this review, we highlight recent findings on IL-17-mediated immunity against C. albicans in mouse and man.

  5. Butyrate enhances disease resistance of chickens by inducing antimicrobial host defense peptide gene expression.

    Science.gov (United States)

    Sunkara, Lakshmi T; Achanta, Mallika; Schreiber, Nicole B; Bommineni, Yugendar R; Dai, Gan; Jiang, Weiyu; Lamont, Susan; Lillehoj, Hyun S; Beker, Ali; Teeter, Robert G; Zhang, Guolong

    2011-01-01

    Host defense peptides (HDPs) constitute a large group of natural broad-spectrum antimicrobials and an important first line of immunity in virtually all forms of life. Specific augmentation of synthesis of endogenous HDPs may represent a promising antibiotic-alternative approach to disease control. In this study, we tested the hypothesis that exogenous administration of butyrate, a major type of short-chain fatty acids derived from bacterial fermentation of undigested dietary fiber, is capable of inducing HDPs and enhancing disease resistance in chickens. We have found that butyrate is a potent inducer of several, but not all, chicken HDPs in HD11 macrophages as well as in primary monocytes, bone marrow cells, and jejuna and cecal explants. In addition, butyrate treatment enhanced the antibacterial activity of chicken monocytes against Salmonella enteritidis, with a minimum impact on inflammatory cytokine production, phagocytosis, and oxidative burst capacities of the cells. Furthermore, feed supplementation with 0.1% butyrate led to a significant increase in HDP gene expression in the intestinal tract of chickens. More importantly, such a feeding strategy resulted in a nearly 10-fold reduction in the bacterial titer in the cecum following experimental infections with S. enteritidis. Collectively, the results indicated that butyrate-induced synthesis of endogenous HDPs is a phylogenetically conserved mechanism of innate host defense shared by mammals and aves, and that dietary supplementation of butyrate has potential for further development as a convenient antibiotic-alternative strategy to enhance host innate immunity and disease resistance. PMID:22073293

  6. Insights from human studies into the host defense against candidiasis

    OpenAIRE

    Filler, Scott G

    2011-01-01

    Candida spp. are the most common cause of mucosal and disseminated fungal infections in humans. Studies using mutant strains of mice have provided initial information about the roles of dectin-1, CARD9, and Th17 cytokines in the host defense against candidiasis. Recent technological advances have resulted in the identification of mutations in specific genes that predispose humans to develop candidal infection. The analysis of individuals with these mutations demonstrates that dectin-1 is crit...

  7. Histones as mediators of host defense, inflammation and thrombosis.

    Science.gov (United States)

    Hoeksema, Marloes; van Eijk, Martin; Haagsman, Henk P; Hartshorn, Kevan L

    2016-03-01

    Histones are known for their ability to bind to and regulate expression of DNA. However, histones are also present in cytoplasm and extracellular fluids where they serve host defense functions and promote inflammatory responses. Histones are a major component of neutrophil extracellular traps that contribute to bacterial killing but also to inflammatory injury. Histones can act as antimicrobial peptides and directly kill bacteria, fungi, parasites and viruses, in vitro and in a variety of animal hosts. In addition, histones can trigger inflammatory responses in some cases acting through Toll-like receptors or inflammasome pathways. Extracellular histones mediate organ injury (lung, liver), sepsis physiology, thrombocytopenia and thrombin generation and some proteins can bind histones and reduce these potentially harmful effects. PMID:26939619

  8. Necroptosis: The Trojan horse in cell autonomous antiviral host defense.

    Science.gov (United States)

    Mocarski, Edward S; Guo, Hongyan; Kaiser, William J

    2015-05-01

    Herpesviruses suppress cell death to assure sustained infection in their natural hosts. Murine cytomegalovirus (MCMV) encodes suppressors of apoptosis as well as M45-encoded viral inhibitor of RIP activation (vIRA) to block RIP homotypic interaction motif (RHIM)-signaling and recruitment of RIP3 (also called RIPK3), to prevent necroptosis. MCMV and human cytomegalovirus encode a viral inhibitor of caspase (Casp)8 activation to block apoptosis, an activity that unleashes necroptosis. Herpes simplex virus (HSV)1 and HSV2 incorporate both RHIM and Casp8 suppression strategies within UL39-encoded ICP6 and ICP10, respectively, which are herpesvirus-conserved homologs of MCMV M45. Both HSV proteins sensitize human cells to necroptosis by blocking Casp8 activity while preventing RHIM-dependent RIP3 activation and death. In mouse cells, HSV1 ICP6 interacts with RIP3 and, surprisingly, drives necroptosis. Thus, herpesviruses have illuminated the contribution of necoptosis to host defense in the natural host as well as its potential to restrict cross-species infections in nonnatural hosts. PMID:25819165

  9. Characterization of a proteolytically stable multifunctional host defense peptidomimetic

    DEFF Research Database (Denmark)

    Jahnsen, Rasmus D; Haney, Evan F; Franzyk, Henrik;

    2013-01-01

    The in vitro activity of a host defense peptidomimetic (HDM-4) was investigated. The compound exhibited an antimicrobial activity profile against a range of Gram-negative bacteria. HDM-4 permeabilized the outer membrane and partly depolarized the inner membrane at its minimal inhibitory concentra......The in vitro activity of a host defense peptidomimetic (HDM-4) was investigated. The compound exhibited an antimicrobial activity profile against a range of Gram-negative bacteria. HDM-4 permeabilized the outer membrane and partly depolarized the inner membrane at its minimal inhibitory......-target antibiotics. HDM-4 exhibited multispecies anti-biofilm activity at sub-MIC levels. Furthermore, HDM-4 modulated the immune response by inducing the release of the chemoattractants interleukin-8 (IL-8), monocyte chemotactic protein-1 (MCP-1), and MCP-3 from human peripheral blood mononuclear cells. In addition......, the compound suppressed lipopolysaccharide-mediated inflammation by reducing the release of the pro-inflammatory cytokines IL-6 and tumor necrosis factor-α....

  10. Green Tea Consumption after Intense Taekwondo Training Enhances Salivary Defense Factors and Antibacterial Capacity

    OpenAIRE

    Lin, Shiuan-Pey; Li, Chia-Yang; Suzuki, Katsuhiko; Chang, Chen-Kang; Chou, Kuei-Ming; Fang, Shih-Hua

    2014-01-01

    The aim of this study was to investigate the short-term effects of green tea consumption on selected salivary defense proteins, antibacterial capacity and anti-oxidation activity in taekwondo (TKD) athletes, following intensive training. Twenty-two TKD athletes performed a 2-hr TKD training session. After training, participants ingested green tea (T, caffeine 6 mg/kg and catechins 22 mg/kg) or an equal volume of water (W). Saliva samples were collected at three time points: before training (B...

  11. Epithelial antimicrobial peptides in host defense against infection

    Directory of Open Access Journals (Sweden)

    Bals Robert

    2000-10-01

    Full Text Available Abstract One component of host defense at mucosal surfaces seems to be epithelium-derived antimicrobial peptides. Antimicrobial peptides are classified on the basis of their structure and amino acid motifs. Peptides of the defensin, cathelicidin, and histatin classes are found in humans. In the airways, α-defensins and the cathelicidin LL-37/hCAP-18 originate from neutrophils. β-Defensins and LL-37/hCAP-18 are produced by the respiratory epithelium and the alveolar macrophage and secreted into the airway surface fluid. Beside their direct antimicrobial function, antimicrobial peptides have multiple roles as mediators of inflammation with effects on epithelial and inflammatory cells, influencing such diverse processes as proliferation, immune induction, wound healing, cytokine release, chemotaxis, protease-antiprotease balance, and redox homeostasis. Further, antimicrobial peptides qualify as prototypes of innovative drugs that might be used as antibiotics, anti-lipopolysaccharide drugs, or modifiers of inflammation.

  12. Granzyme A impairs host defense during Streptococcus pneumoniae pneumonia.

    Science.gov (United States)

    van den Boogaard, Florry E; van Gisbergen, Klaas P J M; Vernooy, Juanita H; Medema, Jan P; Roelofs, Joris J T H; van Zoelen, Marieke A D; Endeman, Henrik; Biesma, Douwe H; Boon, Louis; Van't Veer, Cornelis; de Vos, Alex F; van der Poll, Tom

    2016-08-01

    Streptococcus pneumoniae is the most common causative pathogen in community-acquired pneumonia (CAP). Granzyme A (GzmA) is a serine protease produced by a variety of cell types involved in the immune response. We sought to determine the role of GzmA on the host response during pneumococcal pneumonia. GzmA was measured in bronchoalveolar lavage fluid (BALF) harvested from CAP patients from the infected and contralateral uninfected side and in lung tissue slides from CAP patients and controls. In CAP patients, GzmA levels were increased in BALF obtained from the infected lung. Human lungs showed constitutive GzmA expression by both parenchymal and nonparenchymal cells. In an experimental setting, pneumonia was induced in wild-type (WT) and GzmA-deficient (GzmA(-/-)) mice by intranasal inoculation of S. pneumoniae In separate experiments, WT and GzmA(-/-) mice were treated with natural killer (NK) cell depleting antibodies. Upon infection with S. pneumoniae, GzmA(-/-) mice showed a better survival and lower bacterial counts in BALF and distant body sites compared with WT mice. Although NK cells showed strong GzmA expression, NK cell depletion did not influence bacterial loads in either WT or GzmA(-/-) mice. These results implicate that GzmA plays an unfavorable role in host defense during pneumococcal pneumonia by a mechanism that does not depend on NK cells. PMID:27343190

  13. Addicted? Reduced host resistance in populations with defensive symbionts.

    Science.gov (United States)

    Martinez, Julien; Cogni, Rodrigo; Cao, Chuan; Smith, Sophie; Illingworth, Christopher J R; Jiggins, Francis M

    2016-06-29

    Heritable symbionts that protect their hosts from pathogens have been described in a wide range of insect species. By reducing the incidence or severity of infection, these symbionts have the potential to reduce the strength of selection on genes in the insect genome that increase resistance. Therefore, the presence of such symbionts may slow down the evolution of resistance. Here we investigated this idea by exposing Drosophila melanogaster populations to infection with the pathogenic Drosophila C virus (DCV) in the presence or absence of Wolbachia, a heritable symbiont of arthropods that confers protection against viruses. After nine generations of selection, we found that resistance to DCV had increased in all populations. However, in the presence of Wolbachia the resistant allele of pastrel-a gene that has a major effect on resistance to DCV-was at a lower frequency than in the symbiont-free populations. This finding suggests that defensive symbionts have the potential to hamper the evolution of insect resistance genes, potentially leading to a state of evolutionary addiction where the genetically susceptible insect host mostly relies on its symbiont to fight pathogens. PMID:27335421

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

    Science.gov (United States)

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

    2015-11-01

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

  15. GENES, IN ADDITION TO TOLL-LIKE RECEPTOR 2, PLAY A ROLE IN ANTIBACTERIAL DEFENSE TO STREPTOCOCCAL PNEUMONIA

    Science.gov (United States)

    Streptococcus infection in human populations continues to be a major cause of morbidity and mortality. To evaluate the effect of genetic background and toll-like receptor 2 (TLR2) on antibacterial defense to streptococcal infection, eight genetically diverse strains of mic...

  16. Interleukin-33 Increases Antibacterial Defense by Activation of Inducible Nitric Oxide Synthase in Skin

    OpenAIRE

    Li, Changwei; Li, Hongquan; Jiang, Ziwei; Zhang, Tian; Wang, Yue; Li, Zhiheng; Wu, Yelin; Ji, Shizhao; Xiao, Shichu; Ryffel, Bernhard; Radek, Katherine A.; Xia, Zhaofan; Lai, Yuping

    2014-01-01

    Interleukin-33 (IL-33) is associated with multiple diseases, including asthma, rheumatoid arthritis, tissue injuries and infections. Although IL-33 has been indicated to be involved in Staphylococcus aureus (S. aureus) wound infection, little is known about how IL-33 is regulated as a mechanism to increase host defense against skin bacterial infections. To explore the underlying intricate mechanism we first evaluated the expression of IL-33 in skin from S. aureus-infected human patients. Comp...

  17. Hematopoietic but not endothelial cell MyD88 contributes to host defense during gram-negative pneumonia derived sepsis.

    Directory of Open Access Journals (Sweden)

    Miriam H P van Lieshout

    2014-09-01

    Full Text Available Klebsiella pneumoniae is an important cause of sepsis. The common Toll-like receptor adapter myeloid differentiation primary response gene (MyD88 is crucial for host defense against Klebsiella. Here we investigated the role of MyD88 in myeloid and endothelial cells during Klebsiella pneumosepsis. Mice deficient for MyD88 in myeloid (LysM-Myd88(-/- and myeloid plus endothelial (Tie2-Myd88(-/- cells showed enhanced lethality and bacterial growth. Tie2-Myd88(-/- mice reconstituted with control bone marrow, representing mice with a selective MyD88 deficiency in endothelial cells, showed an unremarkable antibacterial defense. Myeloid or endothelial cell MyD88 deficiency did not impact on lung pathology or distant organ injury during late stage sepsis, while LysM-Myd88(-/- mice demonstrated a strongly attenuated inflammatory response in the airways early after infection. These data suggest that myeloid but not endothelial MyD88 is important for host defense during gram-negative pneumonia derived sepsis.

  18. Antibacterial Peptide CecropinB2 Production via Various Host and Construct Systems

    Directory of Open Access Journals (Sweden)

    Wei-Shiang Lai

    2016-01-01

    Full Text Available Cecropin is a cationic antibacterial peptide composed of 35–39 residues. This peptide has been identified as possessing strong antibacterial activity and low toxicity against eukaryotic cells, and it has been claimed that some types of the cecropin family of peptides are capable of killing cancer cells. In this study, the host effect of cloning antibacterial peptide cecropinB2 was investigated. Three different host expression systems were chosen, i.e., Escherichia coli, Bacillus subtilis and Pichia pastoris. Two gene constructs, cecropinB2 (cecB2 and intein-cecropinB2 (INT-cecB2, were applied. Signal peptide and propeptide from Armigeres subalbatus were also attached to the gene construct. The results showed that the best host for cloning cecropinB2 was P. pastoris SMD1168 harboring the gene of pGAPzαC-prepro-cecB2 via Western blot confirmation. The cecropinB2 that was purified using immobilized-metal affinity chromatography resin showed strong antibacterial activity against the Gram-negative strains, including the multi-drug-resistant bacteria Acinetobacter baumannii.

  19. Molecular sabotage of host plant defenses by spider mites

    OpenAIRE

    Haring, M.A.; Schuurink, R.C.; Kant, M.R.; Villarroel Figueroa, C.A.

    2016-01-01

    Plants constitute an ample source of nutrients for a diversity of organisms that include viruses, microbes, nematodes, insects, and mites. To protect their resources, plants possess a robust immune system that establishes structural and biochemical defenses to fight invaders. Some of these defenses are highly effective but often are very costly to sustain. Thus plants have developed inducible defenses, i.e. they are only produced when needed, regulated by a highly interconnected network in wh...

  20. The effect of chronic exposure to tobacco smoke on the antibacterial defenses of the lung.

    Science.gov (United States)

    Huber, G L; Pochay, V E; Mahajan, V K; McCarthy, C R; Hinds, W C; Davies, P; Drath, D B; Sornberger, G C

    1977-01-01

    To evaluate the effects of cigarette smoking on the host defenses of the lung, male CD rats were exposed to fresh whole smoke for up to 60 consecutive days. Intrapulmonary deposition of smoke and animal exposure levels, quantified with decachlorobiphenyl and other smoke tracers, indicated a daily cigarette exposure equivalent to approximately a pack and a half per day in man. Pulmonary alveolar macrophage function in situ was quantified by the inactivation of an aerosolized challenge of Staphylococcus aureus six hours after inoculation. Controls (n=120) inactivated 88.8+/-0.64% of the staphylococci. Exposure to whole smoke did not impair intrapulmonary antistaphylococcal defenses, with inactivation rates of 89.8+/-0.97% (n=49) and 89.1+/-0.46% (n=74) at 30 and 60 days, respectively. Inactivation distribution frequency analysis in controls revealed that 7% of animals had inactivation values greater than two standard deviations from the mean. With prolonged exposure mean with less skewing towards the abnormal. Alveolar macrophages harvested from smoked animals were comparable in viability and in vitro antistaphylococcal activity to controls, appeared to be metabolically activated and had specific stereologic ultrastructural alterations. These studies indicate that chronic exposure to tobacco smoke does not impair, and in fact may stimulate, the host defenses of the lung, as evaluated by in vivo and in vitro pulmonary alveolar macrophage function. PMID:843645

  1. DMPD: The interferon regulatory factor family in host defense: mechanism of action. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17502370 The interferon regulatory factor family in host defense: mechanism of acti....html) (.csml) Show The interferon regulatory factor family in host defense: mechanism of action. PubmedID 1...7502370 Title The interferon regulatory factor family in host defense: mechanism

  2. Antibacterial activity of the sponge Suberites domuncula and its primmorphs: Potential basis for epibacterial chemical defense

    Digital Repository Service at National Institute of Oceanography (India)

    Thakur, N.L.; Hentschel, U.; Krasko, A; Pabel, C.T.; Anil, A; Mueller, W.E.G.

    ). Moreover, a recombinant perforin-like protein was cloned from S. domuncula that displayed strong antibacterial activity. Based on these observations, it is proposed that the sponge may be provided with a direct (by producing antibacterial metabolites...

  3. Host Defense Pathways: role of redundancy and compensation in infectious disease phenotypes

    OpenAIRE

    Nish, Simone; Medzhitov, Ruslan

    2011-01-01

    Innate host defense pathways consist of microbial sensors, their signaling pathways and the anti-microbial effector mechanisms. Several classes of host defense pathways are currently known, each comprising several pattern-recognition receptors that detect different types of pathogens. These pathways interact with one another in a variety of ways that can be categorized into cooperation, complementation and compensation. Understanding the principles of these interactions is important for bette...

  4. Host defenses against bacterial pore-forming toxins

    OpenAIRE

    Los, F.C.O.

    2011-01-01

    Pore-forming toxins (PFTs), the most common bacterial toxins, contribute to infection by perforating host cell membranes. Excessive use and lack of new development of antibiotics are causing increasing numbers of drug-resistant bacteria, like methicillin-resistant Staphylococcus aureus (MRSA) and Mycobacterium tuberculosis. A review of primary literature shows PFTs may form a viable target for new antibiotics, warranting their further investigation. This thesis describes three studies on host...

  5. Modification of FMDV anti-host defense mechanism

    OpenAIRE

    Guan, Suhua; Belsham, Graham

    2014-01-01

    Foot-and-mouth disease virus (FMDV) is the etiologic agent of FMD, an infectious and sometimes fatal viral disease that affects cloven-hoofed animals. The FMDV genome encodes a large polyprotein, the first component of which is the Leader protein. Unusually, within the picornavirus family, the FMDV Leader protein (Lpro) is a protease. This protease induces a very rapid inhibition of host cell cap-dependent protein synthesis within infected cells. This results from cleavage of the cellular tra...

  6. Diverse Functions of Pulmonary Collectins in Host Defense of the Lung

    OpenAIRE

    Yoshio Kuroki; Chiaki Nishitani; Shigeru Ariki

    2012-01-01

    Pulmonary surfactant is a mixture of lipids and proteins that covers alveolar surfaces and keeps alveoli from collapsing. Four specific proteins have been identified in surfactant. Among them, two C-type lectins, surfactant proteins A and D (SP-A and SP-D), are known to be implicated in host defense and regulation of inflammatory responses of the lung. These host defense lectins are structurally characterized by N-terminal collagen-like domains and lectin domains and are called pulmonary coll...

  7. Symbiotic Bacteria Enable Olive Fly Larvae to Overcome Host Defenses

    International Nuclear Information System (INIS)

    Ripe fruit offer readily available nutrients for many animals, including fruit fly larvae (Diptera: Tephritidae) and their associated rot-inducing bacteria. Yet, during most of their ontogeny, fruit remain chemically defended and effectively suppress herbivores and pathogens by high levels of secondary metabolites. Olive flies (Bactrocera oleae) are uniquely able to develop in unripe olives. Unlike other frugivorous tephritids, the larvae maintain bacteria confined within their midgut caeca. We examined the interaction between larvae, their associated bacteria, and fruit chemical defence, hypothesizing that bacterial contribution to larval development is contingent on the phenology of fruit defensive chemistry. We demonstrate that larvae require their natural complement of bacteria (Candidatus Erwinia dacicola: Enterobacteriaceae) in order to develop in unripe olives. Conversely, when feeding on ripe fruit, larval development proceeds independently of these bacteria. Our experiments suggest that bacteria counteract the inhibitory effect of oleuropein—the principal phenolic glycoside in unripe olives. In light of these results, we suggest that the unique symbiosis in olive flies, compared with other frugivorous tephritids, is understood by considering the relationship between the fly, bacteria and fruit chemistry. When applied in an evolutionary context, this approach may also point out the forces which shaped symbioses across the Tephritidae. (author)

  8. Unmasking host and microbial strategies in the Agrobacterium-plant defense tango.

    Science.gov (United States)

    Hwang, Elizabeth E; Wang, Melinda B; Bravo, Janis E; Banta, Lois M

    2015-01-01

    Coevolutionary forces drive adaptation of both plant-associated microbes and their hosts. Eloquently captured in the Red Queen Hypothesis, the complexity of each plant-pathogen relationship reflects escalating adversarial strategies, but also external biotic and abiotic pressures on both partners. Innate immune responses are triggered by highly conserved pathogen-associated molecular patterns, or PAMPs, that are harbingers of microbial presence. Upon cell surface receptor-mediated recognition of these pathogen-derived molecules, host plants mount a variety of physiological responses to limit pathogen survival and/or invasion. Successful pathogens often rely on secretion systems to translocate host-modulating effectors that subvert plant defenses, thereby increasing virulence. Host plants, in turn, have evolved to recognize these effectors, activating what has typically been characterized as a pathogen-specific form of immunity. Recent data support the notion that PAMP-triggered and effector-triggered defenses are complementary facets of a convergent, albeit differentially regulated, set of immune responses. This review highlights the key players in the plant's recognition and signal transduction pathways, with a focus on the aspects that may limit Agrobacterium tumefaciens infection and the ways it might overcome those defenses. Recent advances in the field include a growing appreciation for the contributions of cytoskeletal dynamics and membrane trafficking to the regulation of these exquisitely tuned defenses. Pathogen counter-defenses frequently manipulate the interwoven hormonal pathways that mediate host responses. Emerging systems-level analyses include host physiological factors such as circadian cycling. The existing literature indicates that varying or even conflicting results from different labs may well be attributable to environmental factors including time of day of infection, temperature, and/or developmental stage of the host plant. PMID:25873923

  9. Impairment of Host Defense against Disseminated Candidiasis in Mice Overexpressing GATA-3▿

    OpenAIRE

    Haraguchi, Norihiro; Ishii, Yukio; Morishima, Yuko; Yoh, Keigyou; Matsuno, Yosuke; Kikuchi, Norihiro; Sakamoto, Tohru; Takahashi, Satoru; HIZAWA, NOBUYUKI

    2010-01-01

    Candida species are the most common source of nosocomial invasive fungal infections. Previous studies have indicated that T-helper immune response is the critical host factor for susceptibility to Candida infection. The transcription factor GATA-3 is known as the master regulator for T-helper type 2 (Th2) differentiation. We therefore investigated the role of GATA-3 in the host defense against systemic Candida infection using GATA-3-overexpressing transgenic mice. The survival of GATA-3-overe...

  10. Sumoylation controls host anti-bacterial response to the gut invasive pathogen Shigella flexneri

    OpenAIRE

    Fritah, S.; Lhocine, N.; Golebiowski, F; Mounier, J; Andrieux, A.; Jouvion, G.; Hay, R T; Sansonetti, P; Dejean, A

    2014-01-01

    Shigella flexneri, the etiological agent of bacillary dysentery, invades the human colonic epithelium and causes its massive inflammatory destruction. Little is known about the post-translational modifications implicated in regulating the host defense pathway against Shigella. Here, we show that SUMO-2 impairs Shigella invasion of epithelial cells in vitro. Using mice haploinsufficient for the SUMO E2 enzyme, we found that sumoylation regulates intestinal permeability and is re...

  11. Fibrinogen Is at the Interface of Host Defense and Pathogen Virulence in Staphylococcus aureus Infection.

    Science.gov (United States)

    Ko, Ya-Ping; Flick, Matthew J

    2016-06-01

    Fibrinogen not only plays a pivotal role in hemostasis but also serves key roles in antimicrobial host defense. As a rapidly assembled provisional matrix protein, fibrin(ogen) can function as an early line of host protection by limiting bacterial growth, suppressing dissemination of microbes to distant sites, and mediating host bacterial killing. Fibrinogen-mediated host antimicrobial activity occurs predominantly through two general mechanisms, namely, fibrin matrices functioning as a protective barrier and fibrin(ogen) directly or indirectly driving host protective immune function. The potential of fibrin to limit bacterial infection and disease has been countered by numerous bacterial species evolving and maintaining virulence factors that engage hemostatic system components within vertebrate hosts. Bacterial factors have been isolated that simply bind fibrinogen or fibrin, promote fibrin polymer formation, or promote fibrin dissolution. Staphylococcus aureus is an opportunistic gram-positive bacterium, the causative agent of a wide range of human infectious diseases, and a prime example of a pathogen exquisitely sensitive to host fibrinogen. Indeed, current data suggest fibrinogen serves as a context-dependent determinant of host defense or pathogen virulence in Staphylococcus infection whose ultimate contribution is dictated by the expression of S. aureus virulence factors, the path of infection, and the tissue microenvironment. PMID:27056151

  12. Chapter 13. Physiology and ecology of host defense against microbial invaders

    Science.gov (United States)

    Insects mount a complex hierarchy of defenses that pathogens must overcome before successful infection is achieved. Behavioral avoidance and antiseptic behaviors by host insects reduce the degree of encounters between the insect and pathogens. Any pathogen that contacts or establishes on a potentia...

  13. Reed warbler hosts fine-tune their defenses to track three decades of cuckoo decline.

    Science.gov (United States)

    Thorogood, Rose; Davies, Nicholas B

    2013-12-01

    Interactions between avian hosts and brood parasites can provide a model for how animals adapt to a changing world. Reed warbler (Acrocephalus scirpaceus) hosts employ costly defenses to combat parasitism by common cuckoos (Cuculus canorus). During the past three decades cuckoos have declined markedly across England, reducing parasitism at our study site (Wicken Fen) from 24% of reed warbler nests in 1985 to 1% in 2012. Here we show with experiments that host mobbing and egg rejection defenses have tracked this decline in local parasitism risk: the proportion of reed warbler pairs mobbing adult cuckoos (assessed by responses to cuckoo mounts and models) has declined from 90% to 38%, and the proportion rejecting nonmimetic cuckoo eggs (assessed by responses to model eggs) has declined from 61% to 11%. This is despite no change in response to other nest enemies or mimetic model eggs. Individual variation in both defenses is predicted by parasitism risk during the host's egg-laying period. Furthermore, the response of our study population to temporal variation in parasitism risk can also explain spatial variation in egg rejection behavior in other populations across Europe. We suggest that spatial and temporal variation in parasitism risk has led to the evolution of plasticity in reed warbler defenses. PMID:24299407

  14. Virus-specific host miRNAs: antiviral defenses or promoters of persistent infection?

    OpenAIRE

    Mahajan, Vinay S.; Drake, Adam; Chen, Jianzhu

    2008-01-01

    The discovery of host-microRNA (miRNA) targets in the genomes of many vertebrate viruses indicates that the corresponding miRNAs are a part of the host’s innate antiviral defense. However, given that viruses evolve much faster than host miRNAs, it is surprising that viral variants lacking these “antiviral” miRNA target sequences have not become established. We present an alternate view that miRNAs are among the host molecules that viruses co-opt to suppress their own replication to evade immu...

  15. Cuckoos combat socially transmitted defenses of reed warbler hosts with a plumage polymorphism.

    Science.gov (United States)

    Thorogood, Rose; Davies, Nicholas B

    2012-08-01

    In predator-prey and host-parasite interactions, an individual's ability to combat an opponent often improves with experience--for example, by learning to identify enemy signals. Although learning occurs through individual experience, individuals can also assess threats from social information. Such recognition could promote the evolution of polymorphisms if socially transmitted defenses depend on enemy morph frequency. This would allow rare variants to evade detection. Female brood parasitic common cuckoos, Cuculus canorus, are either gray or rufous. The gray morph is a Batesian mimic whose hawk-like appearance deters host attack. Hosts reject this disguise through social learning, increasing their own defenses when they witness neighbors mobbing a cuckoo. Our experiments reveal that social learning is specific to the cuckoo morph that neighbors mob. Therefore, while neighbors alert hosts to local cuckoo activity, frequency-dependent social information selects for a cuckoo plumage polymorphism to thwart host detection. Our results suggest that selection for mimicry and polymorphisms comes not only from personal experience but also from social learning. PMID:22859487

  16. OXIDATIVE EPITHELIAL HOST DEFENSE IS REGULATED BY INFECTIOUS AND INFLAMMATORY STIMULI

    OpenAIRE

    Gattas, Monica Valencia; Forteza, Radia; Fragoso, Miryam A.; Fregien, Nevis; Salas, Pedro; Salathe, Matthias; Conner, Gregory E.

    2009-01-01

    Epithelia express oxidative anti-microbial protection that uses lactoperoxidase (LPO), hydrogen peroxide (H2O2) and thiocyanate to generate the reactive hypothiocyanite. Duox1 and Duox2, found in epithelia, are hypothesized to provide H2O2 for use by the LPO. To investigate regulation of oxidative LPO-mediated host defense by bacterial and inflammatory stimuli, LPO and Duox mRNA were followed in differentiated primary human airway epithelial cells, challenged with Pseudomonas aeruginosa flage...

  17. Plasma gelsolin improves lung host defense against pneumonia by enhancing macrophage NOS3 function

    OpenAIRE

    Yang, Zhiping; Chiou, Terry Ting-Yu; Stossel, Thomas P.; Kobzik, Lester

    2015-01-01

    Plasma gelsolin (pGSN) functions as part of the “extracellular actin-scavenging system,” but its potential to improve host defense against infection has not been studied. In a mouse model of primary pneumococcal pneumonia, recombinant human pGSN (rhu-pGSN) caused enhanced bacterial clearance, reduced acute inflammation, and improved survival. In vitro, rhu-pGSN rapidly improved lung macrophage uptake and killing of bacteria (Streptococcus pneumoniae, Escherichia coli, and Francisella tularens...

  18. Lymphotoxin organizes contributions to host defense and metabolic illness from innate lymphoid cells

    OpenAIRE

    Upadhyay, Vaibhav; Fu, Yang-Xin

    2013-01-01

    The lymphotoxin (LT)-pathway is a unique constituent branch of the Tumor Necrosis Superfamily (TNFSF). Use of LT is a critical mechanism by which fetal innate lymphoid cells regulate lymphoid organogenesis. Within recent years, adult innate lymphoid cells have been discovered to utilize this same pathway to regulate IL-22 and IL-23 production for host defense. Notably, genetic studies have linked polymorphisms in the genes encoding LTα to several phenotypes contributing to metabolic syndrome....

  19. Histone Deacetylases in Herpesvirus Replication and Virus-Stimulated Host Defense

    OpenAIRE

    Cristea, Ileana M.; Diner, Benjamin A.; Budayeva, Hanna G.; Guise, Amanda J.

    2013-01-01

    Emerging evidence highlights a critical role for protein acetylation during herpesvirus infection. As prominent modulators of protein acetylation, histone deacetylases (HDACs) are essential transcriptional and epigenetic regulators. Not surprisingly, viruses have evolved a wide array of mechanisms to subvert HDAC functions. Here, we review the mechanisms underlying HDAC regulation during herpesvirus infection. We next discuss the roles of acetylation in host defense against herpesvirus infect...

  20. Diverse Functions of Pulmonary Collectins in Host Defense of the Lung

    Directory of Open Access Journals (Sweden)

    Shigeru Ariki

    2012-01-01

    Full Text Available Pulmonary surfactant is a mixture of lipids and proteins that covers alveolar surfaces and keeps alveoli from collapsing. Four specific proteins have been identified in surfactant. Among them, two C-type lectins, surfactant proteins A and D (SP-A and SP-D, are known to be implicated in host defense and regulation of inflammatory responses of the lung. These host defense lectins are structurally characterized by N-terminal collagen-like domains and lectin domains and are called pulmonary collectins. They prevent dissemination of infectious microbes by their biological activities including agglutination and growth inhibition. They also promote clearance of microbes by enhancing phagocytosis in macrophages. In addition, they interact with the other pattern-recognition molecules, including Toll-like receptors (TLRs and TLR-associated molecules, CD14 and MD-2, and regulate inflammatory responses. Furthermore, recent studies have demonstrated that these collectins modulate functions of neutrophil-derived innate immune molecules by interacting with them. These findings indicate that pulmonary collectins play critical roles in host defense of the lung.

  1. DMPD: The role of type I interferon production by dendritic cells in host defense. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17544561 The role of type I interferon production by dendritic cells in host defens...tml) (.csml) Show The role of type I interferon production by dendritic cells in host defense. PubmedID 1754...4561 Title The role of type I interferon production by dendritic cells in host de

  2. DMPD: Toll-like receptors and the host defense against microbial pathogens: bringingspecificity to the innate-immune system. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 15075354 Toll-like receptors and the host defense against microbial pathogens: bringings... the host defense against microbial pathogens: bringingspecificity to the innate-...immune system. PubmedID 15075354 Title Toll-like receptors and the host defense against microbial pathogens: bringings

  3. The adaptor molecule Trif contributes to murine host defense during Leptospiral infection.

    Science.gov (United States)

    Jayaraman, Priya A; Devlin, Amy A; Miller, Jennifer C; Scholle, Frank

    2016-09-01

    Leptospirosis is a zoonotic disease and is caused by pathogenic species of the Leptospira genus, including Leptospira interrogans (L. interrogans). Humans, domestic and wild animals are susceptible to acute or chronic infection. The innate immune response is a critical defense mechanism against Leptospira interrogans, and has been investigated in mouse models. Murine Toll-like receptors (TLRs) have been shown to be key factors in sensing and responding to L. interrogans infection. Specifically, TLR2, TLR4 and the TLR adaptor molecule MyD88 are essential for host defense against L. interrogans; however, the role of the TLR adaptor molecule TIR-domain-containing adaptor-inducing interferon β (TRIF) in the response to L. interrogans has not been previously determined. In the present study, TRIF was found to play an important role during leptospiral infection. Following challenge with L. interrogans, Trif(-/-) mice exhibited delayed weight gain compared to wild-type mice. Moreover, Trif(-/-) mice exhibited an increase in L. interrogans burden in the kidneys, lungs, and blood at early time points (less than 7days post infection). Multiple components of the innate immune responses were dampened in response to leptospiral infection including transcription and production of cytokines, and the humoral response, which suggested that TRIF contributes to expression and production of cytokines important for the host defense against L. interrogans. PMID:27259371

  4. Acute radiation syndrome (ARS – treatment of the reduced host defense

    Directory of Open Access Journals (Sweden)

    Heslet L

    2012-01-01

    Full Text Available Lars Heslet1, Christiane Bay2, Steen Nepper-Christensen31Serendex ApS, Gentofte; 2University of Copenhagen, Medical Faculty, Copenhagen; 3Department of Head and Neck Surgery, Otorhinolaryngology, Køge University Hospital, Køge, DenmarkBackground: The current radiation threat from the Fukushima power plant accident has prompted rethinking of the contingency plan for prophylaxis and treatment of the acute radiation syndrome (ARS. The well-documented effect of the growth factors (granulocyte colony-stimulating factor [G-CSF] and granulocyte-macrophage colony-stimulating factor [GM-CSF] in acute radiation injury has become standard treatment for ARS in the United States, based on the fact that growth factors increase number and functions of both macrophages and granulocytes.Methods: Review of the current literature.Results: The lungs have their own host defense system, based on alveolar macrophages. After radiation exposure to the lungs, resting macrophages can no longer be transformed, not even during systemic administration of growth factors because G-CSF/GM-CSF does not penetrate the alveoli. Under normal circumstances, locally-produced GM-CSF receptors transform resting macrophages into fully immunocompetent dendritic cells in the sealed-off pulmonary compartment. However, GM-CSF is not expressed in radiation injured tissue due to defervescence of the macrophages. In order to maintain the macrophage’s important role in host defense after radiation exposure, it is hypothesized that it is necessary to administer the drug exogenously in order to uphold the barrier against exogenous and endogenous infections and possibly prevent the potentially lethal systemic infection, which is the main cause of death in ARS.Recommendation: Preemptive treatment should be initiated after suspected exposure of a radiation dose of at least ~2 Gy by prompt dosing of 250–400 µg GM-CSF/m2 or 5 µg/kg G-CSF administered systemically and concomitant inhalation of

  5. Viral RNA Silencing Suppressors (RSS): Novel Strategy of Viruses to Ablate the Host RNA Interference (RNAi) Defense System

    OpenAIRE

    Bivalkar-Mehla, Shalmali; Vakharia, Janaki; Mehla, Rajeev; Abreha, Measho; Kanwar, Jagat Rakesh; Tikoo, Akshay; Chauhan, Ashok

    2010-01-01

    Pathogenic viruses have developed a molecular defense arsenal for their survival by counteracting the host anti-viral system known as RNA interference (RNAi). Cellular RNAi, in addition to regulating gene expression through microRNAs, also serves as a barrier against invasive foreign nucleic acids. RNAi is conserved across the biological species, including plants, animals and invertebrates. Viruses in turn, have evolved mechanisms that can counteract this anti-viral defense of the host. Recen...

  6. Triticum mosaic poacevirus enlists P1 rather than HC-Pro to suppress RNA silencing-mediated host defense

    Science.gov (United States)

    RNA silencing, or posttranscriptional gene silencing (PTGS) is one of the most important defense mechanisms employed by higher plants and animals to defend against viral infections. Plant viruses evolved by adopting divergent proteins, even within single virus families, to counter this host defense ...

  7. NLRC4 and TLR5 each contribute to host defense in respiratory melioidosis.

    Directory of Open Access Journals (Sweden)

    T Eoin West

    2014-09-01

    Full Text Available Burkholderia pseudomallei causes the tropical infection melioidosis. Pneumonia is a common manifestation of melioidosis and is associated with high mortality. Understanding the key elements of host defense is essential to developing new therapeutics for melioidosis. As a flagellated bacterium encoding type III secretion systems, B. pseudomallei may trigger numerous host pathogen recognition receptors. TLR5 is a flagellin sensor located on the plasma membrane. NLRC4, along with NAIP proteins, assembles a canonical caspase-1-dependent inflammasome in the cytoplasm that responds to flagellin (in mice and type III secretion system components (in mice and humans. In a murine model of respiratory melioidosis, Tlr5 and Nlrc4 each contributed to survival. Mice deficient in both Tlr5 and Nlrc4 were not more susceptible than single knockout animals. Deficiency of Casp1/Casp11 resulted in impaired bacterial control in the lung and spleen; in the lung much of this effect was attributable to Nlrc4, despite relative preservation of pulmonary IL-1β production in Nlrc4(-/- mice. Histologically, deficiency of Casp1/Casp11 imparted more severe pulmonary inflammation than deficiency of Nlrc4. The human NLRC4 region polymorphism rs6757121 was associated with survival in melioidosis patients with pulmonary involvement. Co-inheritance of rs6757121 and a functional TLR5 polymorphism had an additive effect on survival. Our results show that NLRC4 and TLR5, key components of two flagellin sensing pathways, each contribute to host defense in respiratory melioidosis.

  8. Exploring the pharmacological potential of promiscuous host-defense peptides: from natural screenings to biotechnological applications

    Directory of Open Access Journals (Sweden)

    Osmar Nascimento Silva

    2011-11-01

    Full Text Available In the last few years, the number of bacteria with enhanced resistance to conventional antibiotics has dramatically increased. Most of such bacteria belong to regular microbial flora, becoming a real challenge, especially for immune-depressed patients. Since the treatment is sometimes extremely expensive, and in some circumstances completely inefficient for the most severe cases, researchers are still determined to discover novel compounds. Among them, host-defense peptides (HDPs have been found as the first natural barrier against microorganisms in nearly all living groups. This molecular class has been gaining attention every day for multiple reasons. For decades, it was believed that these defense peptides had been involved only with the permeation of the lipid bilayer in pathogen membranes, their main target. Currently, it is known that these peptides can bind to numerous targets, as well as lipids including proteins and carbohydrates, from the surface to deep within the cell. Moreover, by using in vivo models, it was shown that host-defense peptides could act both in pathogens and cognate hosts, improving immunological functions as well as acting through multiple pathways to control infections. This review focuses on structural and functional properties of HDP peptides and the additional strategies used to select them. Furthermore, strategies to avoid problems in large scale manufacture by using molecular and biochemical techniques will also be explored. In summary, this review intends to construct a bridge between academic research and pharmaceutical industry, providing novel insights into the utilization of HDPs against resistant bacterial strains that cause infections in humans.

  9. MyD88 Signaling Regulates Both Host Defense and Immunopathogenesis during Pneumocystis Infection

    OpenAIRE

    Bello-Irizarry, Sheila N.; Wang, Jing; Johnston, Carl J.; Gigliotti, Francis; Wright, Terry W.

    2013-01-01

    The immune response protects against Pneumocystis infection, but is also a key component of PcP-related immunopathogenesis. Signaling through MyD88 is critical for activation of immune pathways downstream of TLRs and IL-1 receptor. To determine whether MyD88 regulates normal host defense against Pneumocystis, non-immunosuppressed wild-type (WT) and MyD88 deficient mice were infected. MyD88−/− mice had higher early Pneumocystis burdens than WT mice, but mounted an effective adaptive immune res...

  10. Divergent roles of IL-23 and IL-12 in host defense against Klebsiella pneumoniae

    OpenAIRE

    Happel, Kyle I.; Dubin, Patricia J.; Zheng, Mingquan; Ghilardi, Nico; Lockhart, Christie; Quinton, Lee J.; Odden, Anthony R.; Shellito, Judd E.; Bagby, Gregory J.; Nelson, Steve; Kolls, Jay K.

    2005-01-01

    Interleukin (IL)-23 is a heterodimeric cytokine that shares the identical p40 subunit as IL-12 but exhibits a unique p19 subunit similar to IL-12 p35. IL-12/23 p40, interferon γ (IFN-γ), and IL-17 are critical for host defense against Klebsiella pneumoniae. In vitro, K. pneumoniae–pulsed dendritic cell culture supernatants elicit T cell IL-17 production in a IL-23–dependent manner. However, the importance of IL-23 during in vivo pulmonary challenge is unknown. We show that IL-12/23 p40–defici...

  11. Histone Deacetylases in Herpesvirus Replication and Virus-Stimulated Host Defense

    Directory of Open Access Journals (Sweden)

    Ileana M. Cristea

    2013-06-01

    Full Text Available Emerging evidence highlights a critical role for protein acetylation during herpesvirus infection. As prominent modulators of protein acetylation, histone deacetylases (HDACs are essential transcriptional and epigenetic regulators. Not surprisingly, viruses have evolved a wide array of mechanisms to subvert HDAC functions. Here, we review the mechanisms underlying HDAC regulation during herpesvirus infection. We next discuss the roles of acetylation in host defense against herpesvirus infection. Finally, we provide a perspective on the contribution of current mass spectrometry-based “omic” technologies to infectious disease research, offering a systems biology view of infection.

  12. mRNA expression profiling reveals a role of Helicobacter pylorivacuolating toxin in escaping host defense

    Institute of Scientific and Technical Information of China (English)

    Jian-Ping Yuan; Tao Li; Zhen-Hong Li; Gui-Zhen Yang; Bao-Yu Hu; Xiao-Dong Shi; Tie-Liu Shi; Shan-Qing Tong; Xiao-Kui Guo

    2004-01-01

    AIM: To study the immune response of host to Helicobacter pylori VacA.METHODS: The monocyte/macrophage-like U937 cells were infected with Helicobacter pylori vacA-positive strain NCTC 11638 or isogenic vacA-negative mutant. Differentially expressed genes were identified at 2, 6, 10, and 24 h postinfection by cDNA microarray. Differential expressions of some genes were confirmed by Northern blot.RESULTS: More than 100 genes altered their mRNA expression at different time points respectively, many of which were identified to be related to immune evasion.CONCLUSION: VacA is a crucial element for H pylorito escape from host immune defense by means of differentially regulating the expression of some related genes. These genes, previously known or unknown to be involved in the mechanism of immune evasion, deserve further investigation to unearth much more information complicated in the immune response.

  13. Aggregatibacter actinomycetemcomitans, a potent immunoregulator of the periodontal host defense system and alveolar bone homeostasis.

    Science.gov (United States)

    Herbert, B A; Novince, C M; Kirkwood, K L

    2016-06-01

    Aggregatibacter actinomycetemcomitans is a perio-pathogenic bacteria that has long been associated with localized aggressive periodontitis. The mechanisms of its pathogenicity have been studied in humans and preclinical experimental models. Although different serotypes of A. actinomycetemcomitans have differential virulence factor expression, A. actinomycetemcomitans cytolethal distending toxin (CDT), leukotoxin, and lipopolysaccharide (LPS) have been most extensively studied in the context of modulating the host immune response. Following colonization and attachment in the oral cavity, A. actinomycetemcomitans employs CDT, leukotoxin, and LPS to evade host innate defense mechanisms and drive a pathophysiologic inflammatory response. This supra-physiologic immune response state perturbs normal periodontal tissue remodeling/turnover and ultimately has catabolic effects on periodontal tissue homeostasis. In this review, we have divided the host response into two systems: non-hematopoietic and hematopoietic. Non-hematopoietic barriers include epithelium and fibroblasts that initiate the innate immune host response. The hematopoietic system contains lymphoid and myeloid-derived cell lineages that are responsible for expanding the immune response and driving the pathophysiologic inflammatory state in the local periodontal microenvironment. Effector systems and signaling transduction pathways activated and utilized in response to A. actinomycetemcomitans will be discussed to further delineate immune cell mechanisms during A. actinomycetemcomitans infection. Finally, we will discuss the osteo-immunomodulatory effects induced by A. actinomycetemcomitans and dissect the catabolic disruption of balanced osteoclast-osteoblast-mediated bone remodeling, which subsequently leads to net alveolar bone loss. PMID:26197893

  14. Adult Drosophila melanogaster evolved for antibacterial defense invest in infection-induced expression of both humoral and cellular immunity genes

    Directory of Open Access Journals (Sweden)

    McGraw Elizabeth A

    2011-08-01

    Full Text Available Abstract Background While the transcription of innate immunity genes in response to bacterial infection has been well-characterised in the Drosophila model, we recently demonstrated the capacity for such transcription to evolve in flies selected for improved antibacterial defense. Here we use this experimental system to examine how insects invest in constitutive versus infection-induced transcription of immunity genes. These two strategies carry with them different consequences with respect to energetic and pleiotropic costs and may be more or less effective in improving defense depending on whether the genes contribute to humoral or cellular aspects of immunity. Findings Contrary to expectation we show that selection preferentially increased the infection-induced expression of both cellular and humoral immunity genes. Given their functional roles, infection induced increases in expression were expected for the humoral genes, while increases in constitutive expression were expected for the cellular genes. We also report a restricted ability to improve transcription of immunity genes that is on the order of 2-3 fold regardless of total transcription level of the gene. Conclusions The evolved increases in infection-induced expression of the cellular genes may result from specific cross talk with humoral pathways or from generalised strategies for enhancing immunity gene transcription. A failure to see improvements in constitutive expression of the cellular genes suggests either that increases might come at too great a cost or that patterns of expression in adults are decoupled from the larval phase where increases would be most effective. The similarity in fold change increase across all immunity genes may suggest a shared mechanism for the evolution of increased transcription in small, discrete units such as duplication of cis-regulatory elements.

  15. Plasma gelsolin improves lung host defense against pneumonia by enhancing macrophage NOS3 function

    Science.gov (United States)

    Yang, Zhiping; Chiou, Terry Ting-Yu; Stossel, Thomas P.

    2015-01-01

    Plasma gelsolin (pGSN) functions as part of the “extracellular actin-scavenging system,” but its potential to improve host defense against infection has not been studied. In a mouse model of primary pneumococcal pneumonia, recombinant human pGSN (rhu-pGSN) caused enhanced bacterial clearance, reduced acute inflammation, and improved survival. In vitro, rhu-pGSN rapidly improved lung macrophage uptake and killing of bacteria (Streptococcus pneumoniae, Escherichia coli, and Francisella tularensis). pGSN triggers activating phosphorylation (Ser1177) of macrophage nitric oxide synthase type III (NOS3), an enzyme with important bactericidal functions in lung macrophages. rhu-pGSN failed to enhance bacterial killing by NOS3−/− macrophages in vitro or bacterial clearance in NOS3−/− mice in vivo. Prophylaxis with immunomodulators may be especially relevant for patients at risk for secondary bacterial pneumonia, e.g., after influenza. Treatment of mice with pGSN challenged with pneumococci on postinfluenza day 7 (the peak of enhanced susceptibility to secondary infection) caused a ∼15-fold improvement in bacterial clearance, reduced acute neutrophilic inflammation, and markedly improved survival, even without antibiotic therapy. pGSN is a potential immunomodulator for improving lung host defense against primary and secondary bacterial pneumonia. PMID:25957291

  16. The Role of Dectin-2 for Host Defense Against Disseminated Candidiasis.

    Science.gov (United States)

    Ifrim, Daniela C; Quintin, Jessica; Courjol, Flavie; Verschueren, Ineke; van Krieken, J Han; Koentgen, Frank; Fradin, Chantal; Gow, Neil A R; Joosten, Leo A B; van der Meer, Jos W M; van de Veerdonk, Frank; Netea, Mihai G

    2016-04-01

    Despite the fact that Candida albicans is an important human fungal pathogen and Dectin-2 is a major pattern recognition receptor for fungi, our knowledge regarding the role of Dectin-2 for the host defense against disseminated candidiasis is limited. Dectin-2 deficient (Dectin-2(-/-)) mice were more susceptible to systemic candidiasis, and the susceptibility was mirrored by an elevated fungal load in the kidneys that correlated with the presence of large inflammatory foci. Phagocytosis of Candida by the macrophages lacking the Dectin-2 receptor was moderately decreased, while production of most of the macrophage-derived cytokines from Dectin-2(-/-) mice with systemic candidiasis was decreased. No striking differences among several Candida mutants defective in mannans could be detected between naïve wild-type and Dectin-2(-/-) mice, apart from the β-mannan-deficient bmt1Δ/bmt2Δ/bmt5Δ triple mutant, suggesting that β-mannan may partially mask α-mannan detection, which is the major fungal structure recognized by Dectin-2. Deciphering the mechanisms responsible for host defense against the majority of C. albicans strains represents an important step in understanding the pathophysiology of systemic candidiasis, which might lead to the development of novel immunotherapeutic strategies. PMID:27046240

  17. Plasma gelsolin improves lung host defense against pneumonia by enhancing macrophage NOS3 function.

    Science.gov (United States)

    Yang, Zhiping; Chiou, Terry Ting-Yu; Stossel, Thomas P; Kobzik, Lester

    2015-07-01

    Plasma gelsolin (pGSN) functions as part of the "extracellular actin-scavenging system," but its potential to improve host defense against infection has not been studied. In a mouse model of primary pneumococcal pneumonia, recombinant human pGSN (rhu-pGSN) caused enhanced bacterial clearance, reduced acute inflammation, and improved survival. In vitro, rhu-pGSN rapidly improved lung macrophage uptake and killing of bacteria (Streptococcus pneumoniae, Escherichia coli, and Francisella tularensis). pGSN triggers activating phosphorylation (Ser(1177)) of macrophage nitric oxide synthase type III (NOS3), an enzyme with important bactericidal functions in lung macrophages. rhu-pGSN failed to enhance bacterial killing by NOS3(-/-) macrophages in vitro or bacterial clearance in NOS3(-/-) mice in vivo. Prophylaxis with immunomodulators may be especially relevant for patients at risk for secondary bacterial pneumonia, e.g., after influenza. Treatment of mice with pGSN challenged with pneumococci on postinfluenza day 7 (the peak of enhanced susceptibility to secondary infection) caused a ∼15-fold improvement in bacterial clearance, reduced acute neutrophilic inflammation, and markedly improved survival, even without antibiotic therapy. pGSN is a potential immunomodulator for improving lung host defense against primary and secondary bacterial pneumonia. PMID:25957291

  18. Effects of arsenic trioxide inhalation exposure on pulmonary antibacterial defenses in mice

    International Nuclear Information System (INIS)

    The effects of single and multiple (5 and 20) 3-h inhalation exposures to aerosols of arsenic trioxide on the pulmonary defense system of mice were investigated. Arsenic trioxide mist was generated from an aqueous solution and dried to produce particulate aerosols of 0. 4 micron mass median aerodynamic diameter. Aerosol mass concentration ranged from 125 to 1000 micrograms As/m3. Effects of the exposures were evaluated by determination of changes in susceptibility to experimentally induced streptococcal aerosol infection and in pulmonary bactericidal activity to 35S-labeled Klebsiella pneumoniae. Significant increases in mortality due to the infectious challenge and decreases in bactericidal activity were seen after single 3-h exposures to 270, 500, and 940 micrograms As/m3. Similarly, 5 or 20 multiple 3-h exposures to 500 micrograms As/m3 produced consistently significant increases in mortality and decreases in pulmonary bactericidal activity. At 125 or 250 micrograms As/m3, a decrease in bactericidal activity was seen only after 20 exposures to 250 micrograms/m3. Results from earlier studies with an arsenic-containing copper smelter dust were compared to these data. The possibility of the development of adaptation during multiple exposures to arsenic trioxide is also considered

  19. Roles of d-Amino Acids on the Bioactivity of Host Defense Peptides

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    Hao Li

    2016-06-01

    Full Text Available Host defense peptides (HDPs are positively-charged and amphipathic components of the innate immune system that have demonstrated great potential to become the next generation of broad spectrum therapeutic agents effective against a vast array of pathogens and tumor. As such, many approaches have been taken to improve the therapeutic efficacy of HDPs. Amongst these methods, the incorporation of d-amino acids (d-AA is an approach that has demonstrated consistent success in improving HDPs. Although, virtually all HDP review articles briefly mentioned about the role of d-AA, however it is rather surprising that no systematic review specifically dedicated to this topic exists. Given the impact that d-AA incorporation has on HDPs, this review aims to fill that void with a systematic discussion of the impact of d-AA on HDPs.

  20. Sequestration of host plant glucosinolates in the defensive hemolymph of the sawfly Athalia rosae.

    Science.gov (United States)

    Müller, C; Agerbirk, N; Olsen, C E; Boevé, J L; Schaffner, U; Brakefield, P M

    2001-12-01

    Interactions between insects and glucosinolate-containing plant species have been investigated for a long time. Although the glucosinolate-myrosinase system is believed to act as a defense mechanism against generalist herbivores and fungi, several specialist insects use these secondary metabolites for host plant finding and acceptance and can handle them physiologically. However, sequestration of glucosinolates in specialist herbivores has been less well studied. Larvae of the tumip sawfly Athalia rosae feed on several glucosinolate-containing plant species. When larvae are disturbed by antagonists, they release one or more small droplets of hemolymph from their integument. This "reflex bleeding" is used as a defense mechanism. Specific glucosinolate analysis, by conversion to desulfoglucosinolates and analysis of these by high-performance liquid chromatography coupled to diode array UV spectroscopy and mass spectrometry, revealed that larvae incorporate and concentrate the plant's characteristic glucosinolates from their hosts. Extracts of larvae that were reared on Sinapis alba contained sinalbin, even when the larvae were first starved for 22 hr and, thus, had empty guts. Hemolymph was analyzed from larvae that were reared on either S. alba, Brassica nigra, or Barbarea stricta. Leaves were analyzed from the same plants the larvae had fed on. Sinalbin (from S. alba), sinigrin (B. nigra), or glucobarbarin and glucobrassicin (B. stricta) were present in leaves in concentrations less than 1 micromol/g fresh weight, while the same glucosinolates could be detected in the larvae's hemolymph in concentrations between 10 and 31 micromol/g fresh weight, except that glucobrassicin was present only as a trace. In larval feces, only trace amounts of glucosinolates (sinalbin and sinigrin) could be detected. The glucosinolates were likewise found in freshly emerged adults, showing that the sequestered phytochemicals were transferred through the pupal stage. PMID:11789955

  1. The multifunctional host defense peptide SPLUNC1 is critical for homeostasis of the mammalian upper airway.

    Directory of Open Access Journals (Sweden)

    Glen McGillivary

    Full Text Available Otitis media (OM is a highly prevalent pediatric disease caused by normal flora of the nasopharynx that ascend the Eustachian tube and enter the middle ear. As OM is a disease of opportunity, it is critical to gain an increased understanding of immune system components that are operational in the upper airway and aid in prevention of this disease. SPLUNC1 is an antimicrobial host defense peptide that is hypothesized to contribute to the health of the airway both through bactericidal and non-bactericidal mechanisms. We used small interfering RNA (siRNA technology to knock down expression of the chinchilla ortholog of human SPLUNC1 (cSPLUNC1 to begin to determine the role that this protein played in prevention of OM. We showed that knock down of cSPLUNC1 expression did not impact survival of nontypeable Haemophilus influenzae, a predominant causative agent of OM, in the chinchilla middle ear under the conditions tested. In contrast, expression of cSPLUNC1 was essential for maintenance of middle ear pressure and efficient mucociliary clearance, key defense mechanisms of the tubotympanum. Collectively, our data have provided the first in vivo evidence that cSPLUNC1 functions to maintain homeostasis of the upper airway and, thereby, is critical for protection of the middle ear.

  2. Long-circulating bacteriophage as antibacterial agents.

    OpenAIRE

    Merril, C.R.; B. Biswas; Carlton, R; Jensen, N C; Creed, G J; Zullo, S; Adhya, S

    1996-01-01

    The increased prevalence of multidrug-resistant bacterial pathogens motivated us to attempt to enhance the therapeutic efficacy of bacteriophages. The therapeutic application of phages as antibacterial agents was impeded by several factors: (i) the failure to recognize the relatively narrow host range of phages; (ii) the presence of toxins in crude phage lysates; and (iii) a lack of appreciation for the capacity of mammalian host defense systems, particularly the organs of the reticuloendothe...

  3. Splenic autotransplantation in rabbits: no restoration of response to host defense

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Objective:TO explore the effectiveness of splenic tissue autotransplantation in restoring host defense. Methods: Rabbits were divided into three groups,Sham Operation(SO), Splenic Autotransplantation(SA)and Total Splenectomy(TS), and dynamic changes in histology and immunology were observed for over 24 weeks. Results: Histologic study shows that the white pulps were poorly developed and central arterioles disappeared in the regenerated splenic tissue. The weight of regenerated spleens recovered six months later in SA was 11% of that in SO, and was significantly reduced comparing with the implanted weight( P <0.05). Tere were no significant difference in the number of T lymphocytes and the levels of serum lysozyme among the three groups. A poor antibody response by the rabbits of SA and TS as compared to those of SO was noted after the primary intravenous administration with sheep red blood cells. After the challenge with type 3 pneumococci intravenously, pneumococcal clearance from bloodstream in SA did not differ significantly from that in TS,but was marKedly delayed compared with that in SO(P<0.01). Conclusion: The results indicate that the low quantity and poor quality of the regenerated spleens may contribute to the inferior immunoprotective ability of 1/3 splenic autotransplantation. Therefore, it implies that the regenerated spleens can not fully compensate the original one in im-munology, especially, host resistance to infection.

  4. Emerging Roles of the Host Defense Peptide LL-37 in Human Cancer and its Potential Therapeutic Applications

    OpenAIRE

    WU, WILLIAM K.K.; Wang, Guangshun; Coffelt, Seth B.; Betancourt, Aline M.; Lee, Chung W.; Fan, Daiming; Wu, Kaichun; Yu, Jun; Sung, Joseph J. Y.; Cho, Chi H.

    2010-01-01

    Human cathelicidin LL-37, a host defense peptide derived from leukocytes and epithelial cells, plays a crucial role in innate and adaptive immunity. Not only does it eliminate pathogenic microbes directly, LL-37 also modulates host immune responses. Emerging evidence from tumor biology studies indicates that LL-37 plays a prominent and complex role in carcinogenesis. While overexpression of LL-37 has been implicated in the development or progression of many human malignancies, including breas...

  5. Post-ejection nest-desertion of common cuckoo hosts : a second defense mechanism or avoiding reduced reproductive success?

    NARCIS (Netherlands)

    Moskat, Csaba; Rosendaal, Erik C.; Boers, Myra; Zoelei, Aniko; Ban, Miklos; Komdeur, Jan; Soler, M.

    2011-01-01

    Hosts of the common cuckoo (Cuculus canorus), an avian brood parasite, develop antiparasite defense mechanisms to increase their reproductive success. Ejection of the parasite egg and desertion of the parasitized nest are the most typical adaptations in response to brood parasitism, but nest deserti

  6. Feeding specialization and host-derived chemical defense in Chrysomeline leaf beetles did not lead to an evolutionary dead end

    OpenAIRE

    Termonia, Arnaud; Hsiao, Ting H.; Pasteels, Jacques M.; Milinkovitch, Michel C.

    2001-01-01

    Combination of molecular phylogenetic analyses of Chrysomelina beetles and chemical data of their defensive secretions indicate that two lineages independently developed, from an ancestral autogenous metabolism, an energetically efficient strategy that made the insect tightly dependent on the chemistry of the host plant. However, a lineage (the interrupta group) escaped this subordination through the development of a yet more derived mixed metabolism potentially co...

  7. Cigarette smoke modulates expression of human rhinovirus-induced airway epithelial host defense genes.

    Directory of Open Access Journals (Sweden)

    David Proud

    Full Text Available Human rhinovirus (HRV infections trigger acute exacerbations of chronic obstructive pulmonary disease (COPD and asthma. The human airway epithelial cell is the primary site of HRV infection and responds to infection with altered expression of multiple genes, the products of which could regulate the outcome to infection. Cigarette smoking aggravates asthma symptoms, and is also the predominant risk factor for the development and progression of COPD. We, therefore, examined whether cigarette smoke extract (CSE modulates viral responses by altering HRV-induced epithelial gene expression. Primary cultures of human bronchial epithelial cells were exposed to medium alone, CSE alone, purified HRV-16 alone or to HRV-16+ CSE. After 24 h, supernatants were collected and total cellular RNA was isolated. Gene array analysis was performed to examine mRNA expression. Additional experiments, using real-time RT-PCR, ELISA and/or western blotting, validated altered expression of selected gene products. CSE and HRV-16 each induced groups of genes that were largely independent of each other. When compared to gene expression in response to CSE alone, cells treated with HRV+CSE showed no obvious differences in CSE-induced gene expression. By contrast, compared to gene induction in response to HRV-16 alone, cells exposed to HRV+CSE showed marked suppression of expression of a number of HRV-induced genes associated with various functions, including antiviral defenses, inflammation, viral signaling and airway remodeling. These changes were not associated with altered expression of type I or type III interferons. Thus, CSE alters epithelial responses to HRV infection in a manner that may negatively impact antiviral and host defense outcomes.

  8. Macrophages from Patients with Cirrhotic Ascites Showed Function Alteration of Host Defense Receptor

    Science.gov (United States)

    Ahmed, Abdel Motaal M.; Kadaru, Abdel Gadir Y.; Omer, Ibtihal; Musa, Ahmed M.; Enan, Khalid; El Khidir, Isam M.; Williams, Roger

    2014-01-01

    Background Patients with cirrhotic ascites (PCA) are susceptible to spontaneous bacterial peritonitis (SBP) which has increased morbidity and mortality. Since some host defense aspects of peritoneal macrophages (PMф) from PCA are altered this study examined factors related to receptor-mediated phagocytosis. Methods Twelve PCA were studied. PMɸ were isolated from ascitic fluid (AF) samples removed from these patients. Uptake of mannose receptor (MR)-specific ligand, fluorescein isothiocyanate-mannosylated-bovine serum albumin (FITC-man-BSA), by patients' PMɸ and controls, a human monocytic cell line, was measured pre- and post-IL-4 treatment. Phagocytosis of FITC-labeled yeast particles by patients' PMɸ was measured pre- and post-IL-4 treatment. Fluorescence values were obtained using a spectrofuorometer. MRC1 gene was analyzed in blood samples from PCA and controls, healthy donors, using standard polymerase chain reaction (PCR) technique. Results Past SBP episode(s) were reported in 58.3% of patients. Mean AF volume analyzed per patient was 1.3L. PMɸ ratio in cell yield was 53.73% (SD 18.1). Mean uptake absorbance of patients' PMф was 0.0841 (SD 0.077) compared to 0.338 (SD 0.34) of controls, P = 0.023. Following IL-4 treatment absorbance increased to 0.297 (SD 0.28) in patients' PMф (P = 0.018 on paired sample t-test), and to 0.532 (SD 0.398 in controls (P = 0.053 on independent sample t-test). Mean phagocytosis absorbance of patients' PMф was 0.1250 (SD 0.032) before IL-4 treatment compared to 0.2300 (SD 0.104) after (P = 0.026). PCR analysis for MRC1 gene was negative in all PCA samples compared to positive results in all controls. Conclusion Since decreased phagocytosis and MR uptake were enhanced post-IL-4 treatment MR downregulation pre-treatment is plausible. Negative PCR results for MRC1 might suggest an anomaly, but this awaits further ellucidation. These altered host defense findings are relevant to infection pathophysiology, and their

  9. POU2AF1 Functions in the Human Airway Epithelium To Regulate Expression of Host Defense Genes.

    Science.gov (United States)

    Zhou, Haixia; Brekman, Angelika; Zuo, Wu-Lin; Ou, Xuemei; Shaykhiev, Renat; Agosto-Perez, Francisco J; Wang, Rui; Walters, Matthew S; Salit, Jacqueline; Strulovici-Barel, Yael; Staudt, Michelle R; Kaner, Robert J; Mezey, Jason G; Crystal, Ronald G; Wang, Guoqing

    2016-04-01

    In the process of seeking novel lung host defense regulators by analyzing genome-wide RNA sequence data from normal human airway epithelium, we detected expression of POU domain class 2-associating factor 1 (POU2AF1), a known transcription cofactor previously thought to be expressed only in lymphocytes. Lymphocyte contamination of human airway epithelial samples obtained by bronchoscopy and brushing was excluded by immunohistochemistry staining, the observation of upregulation of POU2AF1 in purified airway basal stem/progenitor cells undergoing differentiation, and analysis of differentiating single basal cell clones. Lentivirus-mediated upregulation of POU2AF1 in airway basal cells induced upregulation of host defense genes, including MX1, IFIT3, IFITM, and known POU2AF1 downstream genes HLA-DRA, ID2, ID3, IL6, and BCL6. Interestingly, expression of these genes paralleled changes of POU2AF1 expression during airway epithelium differentiation in vitro, suggesting POU2AF1 helps to maintain a host defense tone even in pathogen-free condition. Cigarette smoke, a known risk factor for airway infection, suppressed POU2AF1 expression both in vivo in humans and in vitro in human airway epithelial cultures, accompanied by deregulation of POU2AF1 downstream genes. Finally, enhancing POU2AF1 expression in human airway epithelium attenuated the suppression of host defense genes by smoking. Together, these findings suggest a novel function of POU2AF1 as a potential regulator of host defense genes in the human airway epithelium. PMID:26927796

  10. Rapid host defense against Aspergillus fumigatus involves alveolar macrophages with a predominance of alternatively activated phenotype.

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    Shikha Bhatia

    Full Text Available The ubiquitous fungus Aspergillus fumigatus is associated with chronic diseases such as invasive pulmonary aspergillosis in immunosuppressed patients and allergic bronchopulmonary aspergillosis (ABPA in patients with cystic fibrosis or severe asthma. Because of constant exposure to this fungus, it is critical for the host to exercise an immediate and decisive immune response to clear fungal spores to ward off disease. In this study, we observed that rapidly after infection by A. fumigatus, alveolar macrophages predominantly express Arginase 1 (Arg1, a key marker of alternatively activated macrophages (AAMs. The macrophages were also found to express Ym1 and CD206 that are also expressed by AAMs but not NOS2, which is expressed by classically activated macrophages. The expression of Arg1 was reduced in the absence of the known signaling axis, IL-4Rα/STAT6, for AAM development. While both Dectin-1 and TLR expressed on the cell surface have been shown to sense A. fumigatus, fungus-induced Arg1 expression in CD11c(+ alveolar macrophages was not dependent on either Dectin-1 or the adaptor MyD88 that mediates intracellular signaling by most TLRs. Alveolar macrophages from WT mice efficiently phagocytosed fungal conidia, but those from mice deficient in Dectin-1 showed impaired fungal uptake. Depletion of macrophages with clodronate-filled liposomes increased fungal burden in infected mice. Collectively, our studies suggest that alveolar macrophages, which predominantly acquire an AAM phenotype following A. fumigatus infection, have a protective role in defense against this fungus.

  11. A host defense mechanism involving CFTR-mediated bicarbonate secretion in bacterial prostatitis.

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    Chen Xie

    Full Text Available BACKGROUND: Prostatitis is associated with a characteristic increase in prostatic fluid pH; however, the underlying mechanism and its physiological significance have not been elucidated. METHODOLOGY/PRINCIPAL FINDINGS: In this study a primary culture of rat prostatic epithelial cells and a rat prostatitis model were used. Here we reported the involvement of CFTR, a cAMP-activated anion channel conducting both Cl(- and HCO(3(-, in mediating prostate HCO(3(- secretion and its possible role in bacterial killing. Upon Escherichia coli (E. coli-LPS challenge, the expression of CFTR and carbonic anhydrase II (CA II, along with several pro-inflammatory cytokines was up-regulated in the primary culture of rat prostate epithelial cells. Inhibiting CFTR function in vitro or in vivo resulted in reduced bacterial killing by prostate epithelial cells or the prostate. High HCO(3(- content (>50 mM, rather than alkaline pH, was found to be responsible for bacterial killing. The direct action of HCO(3(- on bacterial killing was confirmed by its ability to increase cAMP production and suppress bacterial initiation factors in E. coli. The relevance of the CFTR-mediated HCO(3(- secretion in humans was demonstrated by the upregulated expression of CFTR and CAII in human prostatitis tissues. CONCLUSIONS/SIGNIFICANCE: The CFTR and its mediated HCO(3(- secretion may be up-regulated in prostatitis as a host defense mechanism.

  12. Pathogenicity of Toxoplasma gondii through B-2 cell-mediated downregulation of host defense responses

    International Nuclear Information System (INIS)

    IFN-γ is the primary mediator of anti-parasite effector mechanisms against Toxoplasma gondii. After intraperitoneal infection with the Fukaya strain of T. gondii, unirradiated IFN-γ knock-out (GKO) mice transferred with wild type (WT) CD8+ effector T cells from infected mice failed to induce the production of IFN-γ and died, whereas irradiated (IR) GKO mice transferred with WT CD8+ T cells induced IFN-γ production and survived more than 6 months. IR GKO mice transferred with WT CD8+ T cells together with GKO B-2 cells died 8 days after infection, whereas those transferred with WT CD8+ T cells together with B-1a or T cells survived. B-2 cells of infected GKO mice activated CD11b+ cells for IL-4 production, and down-regulated NO release, STAT1 phosphorylation, and interferon regulatory factor-1 expression in the peritoneal exudates cells of IR GKO mice transferred with WT CD8+ T cells together with GKO B-2 cells after infection. Thus, B-2 cells in T. gondii-infected mice act as suppressor cells in the host defense of infected mice. (author)

  13. Microbial pathogens trigger host DNA double-strand breaks whose abundance is reduced by plant defense responses.

    Directory of Open Access Journals (Sweden)

    Junqi Song

    2014-04-01

    Full Text Available Immune responses and DNA damage repair are two fundamental processes that have been characterized extensively, but the links between them remain largely unknown. We report that multiple bacterial, fungal and oomycete plant pathogen species induce double-strand breaks (DSBs in host plant DNA. DNA damage detected by histone γ-H2AX abundance or DNA comet assays arose hours before the disease-associated necrosis caused by virulent Pseudomonas syringae pv. tomato. Necrosis-inducing paraquat did not cause detectable DSBs at similar stages after application. Non-pathogenic E. coli and Pseudomonas fluorescens bacteria also did not induce DSBs. Elevation of reactive oxygen species (ROS is common during plant immune responses, ROS are known DNA damaging agents, and the infection-induced host ROS burst has been implicated as a cause of host DNA damage in animal studies. However, we found that DSB formation in Arabidopsis in response to P. syringae infection still occurs in the absence of the infection-associated oxidative burst mediated by AtrbohD and AtrbohF. Plant MAMP receptor stimulation or application of defense-activating salicylic acid or jasmonic acid failed to induce a detectable level of DSBs in the absence of introduced pathogens, further suggesting that pathogen activities beyond host defense activation cause infection-induced DNA damage. The abundance of infection-induced DSBs was reduced by salicylic acid and NPR1-mediated defenses, and by certain R gene-mediated defenses. Infection-induced formation of γ-H2AX still occurred in Arabidopsis atr/atm double mutants, suggesting the presence of an alternative mediator of pathogen-induced H2AX phosphorylation. In summary, pathogenic microorganisms can induce plant DNA damage. Plant defense mechanisms help to suppress rather than promote this damage, thereby contributing to the maintenance of genome integrity in somatic tissues.

  14. 137 Interplay between host defenses and viral anti-defenses as a major factor of viral cytopathogenicity

    OpenAIRE

    Agol, Vadim I.

    2014-01-01

    The prevailing paradigm posits that virus-induced cellular injuries (cytopathic effect, CPE) are caused by hijacking of cellular substrates, energy, and infrastructure by the pathogens for the needs of their reproduction. However, this appears to be not the sole, and even not the most important, mechanism of cellular pathology triggered by viral infections. There is ground to believe that the most severe harm may come not from viral reproduction as such but rather from (miscalculated) host de...

  15. The Role of Surfactant in Lung Disease and Host Defense against Pulmonary Infections.

    Science.gov (United States)

    Han, SeungHye; Mallampalli, Rama K

    2015-05-01

    Pulmonary surfactant is essential for life as it lines the alveoli to lower surface tension, thereby preventing atelectasis during breathing. Surfactant is enriched with a relatively unique phospholipid, termed dipalmitoylphosphatidylcholine, and four surfactant-associated proteins, SP-A, SP-B, SP-C, and SP-D. The hydrophobic proteins, SP-B and SP-C, together with dipalmitoylphosphatidylcholine, confer surface tension-lowering properties to the material. The more hydrophilic surfactant components, SP-A and SP-D, participate in pulmonary host defense and modify immune responses. Specifically, SP-A and SP-D bind and partake in the clearance of a variety of bacterial, fungal, and viral pathogens and can dampen antigen-induced immune function of effector cells. Emerging data also show immunosuppressive actions of some surfactant-associated lipids, such as phosphatidylglycerol. Conversely, microbial pathogens in preclinical models impair surfactant synthesis and secretion, and microbial proteinases degrade surfactant-associated proteins. Deficiencies of surfactant components are classically observed in the neonatal respiratory distress syndrome, where surfactant replacement therapies have been the mainstay of treatment. However, functional or compositional deficiencies of surfactant are also observed in a variety of acute and chronic lung disorders. Increased surfactant is seen in pulmonary alveolar proteinosis, a disorder characterized by a functional deficiency of the granulocyte-macrophage colony-stimulating factor receptor or development of granulocyte-macrophage colony-stimulating factor antibodies. Genetic polymorphisms of some surfactant proteins such as SP-C are linked to interstitial pulmonary fibrosis. Here, we briefly review the composition, antimicrobial properties, and relevance of pulmonary surfactant to lung disorders and present its therapeutic implications. PMID:25742123

  16. Depression as sickness behavior? A test of the host defense hypothesis in a high pathogen population.

    Science.gov (United States)

    Stieglitz, Jonathan; Trumble, Benjamin C; Thompson, Melissa Emery; Blackwell, Aaron D; Kaplan, Hillard; Gurven, Michael

    2015-10-01

    Sadness is an emotion universally recognized across cultures, suggesting it plays an important functional role in regulating human behavior. Numerous adaptive explanations of persistent sadness interfering with daily functioning (hereafter "depression") have been proposed, but most do not explain frequent bidirectional associations between depression and greater immune activation. Here we test several predictions of the host defense hypothesis, which posits that depression is part of a broader coordinated evolved response to infection or tissue injury (i.e. "sickness behavior") that promotes energy conservation and reallocation to facilitate immune activation. In a high pathogen population of lean and relatively egalitarian Bolivian forager-horticulturalists, we test whether depression and its symptoms are associated with greater baseline concentration of immune biomarkers reliably associated with depression in Western populations (i.e. tumor necrosis factor alpha [TNF-α], interleukin-1 beta [IL-1β], interleukin-6 [IL-6], and C-reactive protein [CRP]). We also test whether greater pro-inflammatory cytokine responses to ex vivo antigen stimulation are associated with depression and its symptoms, which is expected if depression facilitates immune activation. These predictions are largely supported in a sample of older adult Tsimane (mean±SD age=53.2±11.0, range=34-85, n=649) after adjusting for potential confounders. Emotional, cognitive and somatic symptoms of depression are each associated with greater immune activation, both at baseline and in response to ex vivo stimulation. The association between depression and greater immune activation is therefore not unique to Western populations. While our findings are not predicted by other adaptive hypotheses of depression, they are not incompatible with those hypotheses and future research is necessary to isolate and test competing predictions. PMID:26044086

  17. The zebrafish embryo as a tool for screening and characterizing pleurocidin host-defense peptides as anti-cancer agents

    OpenAIRE

    Michael G. Morash; Douglas, Susan E.; Anna Robotham; Ridley, Christina M.; Gallant, Jeffrey W.; Soanes, Kelly H.

    2011-01-01

    SUMMARY The emergence of multidrug-resistant cancers and the lack of targeted therapies for many cancers underscore an unmet need for new therapeutics with novel modes of action towards cancer cells. Host-defense peptides often exhibit selective cytotoxicity towards cancer cells and show potential as anti-cancer therapeutics. Here, we screen 26 naturally occurring variants of the peptide pleurocidin for cytotoxic and anti-cancer activities, and investigate the underlying mechanism of action. ...

  18. An essential role for the NLRP3 inflammasome in host defense against the human fungal pathogen, Candida albicans

    OpenAIRE

    Hise, Amy G.; Tomalka, Jeffrey; Ganesan, Sandhya; Patel, Krupen; Hall, Brian A.; Brown, Gordon D.; Fitzgerald, Katherine A.

    2009-01-01

    Candida albicans is an opportunistic fungal pathogen causing life-threatening mucosal and systemic infections in immunocompromised humans. Using a murine model of mucosal Candida infection we investigated the role of the proinflammatory cytokine IL-1β in host-defense to Candida albicans. We find that the synthesis, processing and release of IL-1β in response to Candida are tightly controlled and first require transcriptional induction, followed by a second signal leading to caspase-1 mediated...

  19. The zebrafish embryo as a tool for screening and characterizing pleurocidin host-defense peptides as anti-cancer agents

    OpenAIRE

    Morash, Michael G.; Douglas, Susan E.; Anna Robotham; Ridley, Christina M.; Gallant, Jeffrey W.; Soanes, Kelly H.

    2011-01-01

    SUMMARY The emergence of multidrug-resistant cancers and the lack of targeted therapies for many cancers underscore an unmet need for new therapeutics with novel modes of action towards cancer cells. Host-defense peptides often exhibit selective cytotoxicity towards cancer cells and show potential as anti-cancer therapeutics. Here, we screen 26 naturally occurring variants of the peptide pleurocidin for cytotoxic and anti-cancer activities, and investigate the underlying mechanism of actio...

  20. Induction of Porcine Host Defense Peptide Gene Expression by Short-Chain Fatty Acids and Their Analogs

    OpenAIRE

    Zeng, Xiangfang; Sunkara, Lakshmi T; Jiang, Weiyu; Bible, Megan; Carter, Scott; Ma, Xi; Qiao, Shiyan; Zhang, Guolong

    2013-01-01

    Dietary modulation of the synthesis of endogenous host defense peptides (HDPs) represents a novel antimicrobial approach for disease control and prevention, particularly against antibiotic-resistant infections. However, HDP regulation by dietary compounds such as butyrate is species-dependent. To examine whether butyrate could induce HDP expression in pigs, we evaluated the expressions of a panel of porcine HDPs in IPEC-J2 intestinal epithelial cells, 3D4/31 macrophages, and primary monocytes...

  1. Morphine Disrupts Interleukin-23 (IL-23)/IL-17-Mediated Pulmonary Mucosal Host Defense against Streptococcus pneumoniae Infection▿

    OpenAIRE

    Ma, Jing; Wang, Jinghua; Wan, Jing; Charboneau, Richard; Chang, Yaping; Barke, Roderick A.; Roy, Sabita

    2009-01-01

    Streptococcus pneumoniae is a pathogen that causes serious respiratory disease and meningitis in the immunocompromised drug abuse population. However, the precise mechanisms by which drug abuse compromises the host immune defense to pulmonary S. pneumoniae infection is not fully understood. Using a well-established murine model of opiate abuse and S. pneumoniae lung infection, we explored the influence of morphine treatment on the interleukin-23 (IL-23)/IL-17 axis and related innate immunity....

  2. Spontaneous elaboration of transforming growth factor beta suppresses host defense against bacterial infection in autoimmune MRL/lpr mice

    OpenAIRE

    1994-01-01

    Infection with gram-negative and gram-positive bacteria remains a leading cause of death in patients with systemic lupus erythematosis (SLE), even in the absence of immunosuppressive therapy. To elucidate the mechanisms that underly the increased risk of infection observed in patients with systemic autoimmunity, we have investigated host defense against bacterial infection in a murine model of autoimmunity, the MRL/Mp-lpr/lpr (MRL/lpr) mouse. Our previous study implicated transforming growth ...

  3. Skin Electroporation of a Plasmid Encoding hCAP-18/LL-37 Host Defense Peptide Promotes Wound Healing

    OpenAIRE

    Steinstraesser, Lars; Lam, Martin C; Jacobsen, Frank; Porporato, Paolo E; Chereddy, Kiran Kumar; Becerikli, Mustafa; Stricker, Ingo; Hancock, Robert EW; Lehnhardt, Marcus; Sonveaux, Pierre; Préat, Véronique; Vandermeulen, Gaëlle

    2014-01-01

    Host defense peptides, in particular LL-37, are emerging as potential therapeutics for promoting wound healing and inhibiting bacterial growth. However, effective delivery of the LL-37 peptide remains limiting. We hypothesized that skin-targeted electroporation of a plasmid encoding hCAP-18/LL-37 would promote the healing of wounds. The plasmid was efficiently delivered to full-thickness skin wounds by electroporation and it induced expression of LL-37 in the epithelium. It significantly acce...

  4. Killing of trypanosomatid parasites by a modified bovine host defense peptide, BMAP-18.

    Directory of Open Access Journals (Sweden)

    Lee R Haines

    Full Text Available BACKGROUND: Tropical diseases caused by parasites continue to cause socioeconomic devastation that reverberates worldwide. There is a growing need for new control measures for many of these diseases due to increasing drug resistance exhibited by the parasites and problems with drug toxicity. One new approach is to apply host defense peptides (HDP; formerly called antimicrobial peptides to disease control, either to treat infected hosts, or to prevent disease transmission by interfering with parasites in their insect vectors. A potent anti-parasite effector is bovine myeloid antimicrobial peptide-27 (BMAP-27, a member of the cathelicidin family. Although BMAP-27 is a potent inhibitor of microbial growth, at higher concentrations it also exhibits cytotoxicity to mammalian cells. We tested the anti-parasite activity of BMAP-18, a truncated peptide that lacks the hydrophobic C-terminal sequence of the BMAP-27 parent molecule, an alteration that confers reduced toxicity to mammalian cells. METHODOLOGY/PRINCIPAL FINDINGS: BMAP-18 showed strong growth inhibitory activity against several species and life cycle stages of African trypanosomes, fish trypanosomes and Leishmania parasites in vitro. When compared to native BMAP-27, the truncated BMAP-18 peptide showed reduced cytotoxicity on a wide variety of mammalian and insect cells and on Sodalis glossindius, a bacterial symbiont of the tsetse vector. The fluorescent stain rhodamine 123 was used in immunofluorescence microscopy and flow cytometry experiments to show that BMAP-18 at low concentrations rapidly disrupted mitochondrial potential without obvious alteration of parasite plasma membranes, thus inducing death by apoptosis. Scanning electron microscopy revealed that higher concentrations of BMAP-18 induced membrane lesions in the parasites as early as 15 minutes after exposure, thus killing them by necrosis. In addition to direct killing of parasites, BMAP-18 was shown to inhibit LPS

  5. ELR chemokine signaling in host defense and disease in a viral model of central nervous system disease

    Directory of Open Access Journals (Sweden)

    Martin P Hosking

    2014-06-01

    Full Text Available Intracranial infection of the neurotropic JHM strain of mouse hepatitis virus (JHMV into the central nervous system (CNS of susceptible strains of mice results in an acute encephalomyelitis, accompanied by viral replication in glial cells and robust infiltration of virus-specific T cells that contribute to host defense through cytokine secretion and cytolytic activity. Mice that survive the acute stage of disease develop an immune-mediated demyelinating diseases characterized by viral persistence in white matter tracts and a chronic neuroinflammatory response dominated by T cells and macrophages. Early following JHMV infection, there is a dynamic expression of chemokines and chemokine receptors that contribute to neuroinflammation by regulating innate and adaptive immune responses as well influencing glial biology. In response to JHMV infection, we have shown that signaling through the chemokine receptor CXCR2 contributes to host defense through recruitment of polymorphonuclear cells (PMNs to the CNS that enhance permeability of the blood-brain-barrier (BBB and facilitating entry of virus-specific T cells into the parenchyma. Further, CXCR2 promotes the protection of oligodendroglia from cytokine-induced apoptosis and restricts the severity of demyelination. This review covers aspects related to the role of CXCR2 in host defense and disease in response to JHMV infection.

  6. Multitasking antimicrobial peptides, plant development, and host defense against biotic/abiotic stress

    Science.gov (United States)

    Crop losses due to pathogens are a major threat to global food security. Plants employ a multilayer defense system against pathogens including use of physical barriers (cell wall), induction of hypersensitive defense response (HR), resistance (R) proteins, and synthesis of antimicrobial peptides (AM...

  7. Thiamine induced resistance to Plasmopara viticola in grapevine and elicited host-defense responses, including HR like-cell death.

    Science.gov (United States)

    Boubakri, Hatem; Wahab, Mohamed Ali; Chong, Julie; Bertsch, Christophe; Mliki, Ahmed; Soustre-Gacougnolle, Isabelle

    2012-08-01

    Recently, thiamine (VitaminB1) has been shown to induce resistance against Pseudomonas syringae in Arabidopsis plants through priming of defense responses. In this paper, we have demonstrated the efficiency of thiamine to induce resistance against downy mildew caused by the oomycete Plasmopara viticola in a susceptible Vitis vinifera cultivar "Chardonnay" under glasshouse controlled conditions by providing a dual mode of action involving direct antifungal activity and elicitation of host-defense responses. Thiamine-induced defense responses included the generation of hydrogen peroxide (H(2)O(2)) in both grapevine suspension cultured cells (SCC) and plant leaves, upregulation of an array of defense-related genes and the induction of other defense responses at subcellular level such as callose deposition in stomata cells, phenolic compounds accumulation and hypersensitive response (HR) like-cell death. Epifluorescence microscopy studies revealed dramatic changes in P. viticola individual developmental stages during its colonization of the intercellular space of the leaf mesophyll in thiamine-treated plants. Collectively, our report evidenced the efficiency of thiamine in the control of downy mildew in grapevine by direct and indirect effects, suggesting that thiamine could be an attractive alternative to chemical fungicides in disease management in vineyards. PMID:22698755

  8. Structurally Distinct Bacterial TBC-like GAPs Link Arf GTPase to Rab1 Inactivation to Counteract Host Defenses

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Na; Zhu, Yongqun; Lu, Qiuhe; Hu, Liyan; Zheng, Yuqing; Shao, Feng (NIBS-China); (Zhejiang)

    2012-10-10

    Rab GTPases are frequent targets of vacuole-living bacterial pathogens for appropriate trafficking of the vacuole. Here we discover that bacterial effectors including VirA from nonvacuole Shigella flexneri and EspG from extracellular Enteropathogenic Escherichia coli (EPEC) harbor TBC-like dual-finger motifs and exhibits potent RabGAP activities. Specific inactivation of Rab1 by VirA/EspG disrupts ER-to-Golgi trafficking. S. flexneri intracellular persistence requires VirA TBC-like GAP activity that mediates bacterial escape from autophagy-mediated host defense. Rab1 inactivation by EspG severely blocks host secretory pathway, resulting in inhibited interleukin-8 secretion from infected cells. Crystal structures of VirA/EspG-Rab1-GDP-aluminum fluoride complexes highlight TBC-like catalytic role for the arginine and glutamine finger residues and reveal a 3D architecture distinct from that of the TBC domain. Structure of Arf6-EspG-Rab1 ternary complex illustrates a pathogenic signaling complex that rewires host Arf signaling to Rab1 inactivation. Structural distinctions of VirA/EspG further predict a possible extensive presence of TBC-like RabGAP effectors in counteracting various host defenses.

  9. Host defense against viral infection involves interferon mediated down-regulation of sterol biosynthesis.

    Directory of Open Access Journals (Sweden)

    Mathieu Blanc

    2011-03-01

    transcription level. The reduction in srebf2 gene transcription upon infection and IFN treatment is also found to be strictly dependent on ifnar1. Altogether these results show that type 1 IFN signaling is both necessary and sufficient for reducing the sterol metabolic network activity upon infection, thereby linking the regulation of the sterol pathway with interferon anti-viral defense responses. These findings bring a new link between sterol metabolism and interferon antiviral response and support the idea of using host metabolic modifiers of innate immunity as a potential antiviral strategy.

  10. A Systems Biology Approach to the Coordination of Defensive and Offensive Molecular Mechanisms in the Innate and Adaptive Host-Pathogen Interaction Networks.

    Science.gov (United States)

    Wu, Chia-Chou; Chen, Bor-Sen

    2016-01-01

    Infected zebrafish coordinates defensive and offensive molecular mechanisms in response to Candida albicans infections, and invasive C. albicans coordinates corresponding molecular mechanisms to interact with the host. However, knowledge of the ensuing infection-activated signaling networks in both host and pathogen and their interspecific crosstalk during the innate and adaptive phases of the infection processes remains incomplete. In the present study, dynamic network modeling, protein interaction databases, and dual transcriptome data from zebrafish and C. albicans during infection were used to infer infection-activated host-pathogen dynamic interaction networks. The consideration of host-pathogen dynamic interaction systems as innate and adaptive loops and subsequent comparisons of inferred innate and adaptive networks indicated previously unrecognized crosstalk between known pathways and suggested roles of immunological memory in the coordination of host defensive and offensive molecular mechanisms to achieve specific and powerful defense against pathogens. Moreover, pathogens enhance intraspecific crosstalk and abrogate host apoptosis to accommodate enhanced host defense mechanisms during the adaptive phase. Accordingly, links between physiological phenomena and changes in the coordination of defensive and offensive molecular mechanisms highlight the importance of host-pathogen molecular interaction networks, and consequent inferences of the host-pathogen relationship could be translated into biomedical applications. PMID:26881892

  11. Lipooligosaccharide structure is an important determinant in the resistance of Neisseria gonorrhoeae to antimicrobial agents of innate host defense

    Directory of Open Access Journals (Sweden)

    Jacqueline T Balthazar

    2011-02-01

    Full Text Available The strict human pathogen Neisseria gonorrhoeae has caused the sexually transmitted infection termed gonorrhea for thousands of years. Over the millennia, the gonococcus has likely evolved mechanisms to evade host defense systems that operate on the genital mucosal surfaces in both males and females. Past research has shown that the presence or modification of certain cell envelope structures can significantly impact levels of gonococcal susceptibility to host-derived antimicrobial compounds that bathe genital mucosal surfaces and participate in innate host defense against invading pathogens. In order to facilitate the identification of gonococcal genes that are important in determining levels of bacterial susceptibility to mediators of innate host defense, we used the Himar I mariner in vitro mutagenesis system to construct a transposon insertion library in strain F62. As proof of principle that this strategy would be suitable for this purpose, we screened the library for mutants expressing decreased susceptibility to the bacteriolytic action of normal human serum (NHS. We found that a transposon insertion in the lgtD gene, which encodes an N-acetylgalactosamine transferase involved in the extension of the α-chain of lipooligosaccharide (LOS, could confer decreased susceptibility of strain F62 to complement-mediated killing by NHS. By complementation and chemical analyses, we demonstrated both linkage of the transposon insertion to the NHS-resistance phenotype and chemical changes in LOS structure that resulted from loss of LgtD production. Further truncation of the LOS α-chain or loss of phosphoethanolamine (PEA from the lipid A region of LOS also impacted levels of NHS-resistance. PEA decoration of lipid A also increased gonococcal resistance to the model cationic antimicrobial polymyxin B. Taken together, we conclude that the Himar I mariner in vitro mutagenesis procedure can facilitate studies on structures involved in gonococcal

  12. M-CSF Mediates Host Defense during Bacterial Pneumonia by Promoting the Survival of Lung and Liver Mononuclear Phagocytes.

    Science.gov (United States)

    Bettina, Alexandra; Zhang, Zhimin; Michels, Kathryn; Cagnina, R Elaine; Vincent, Isaah S; Burdick, Marie D; Kadl, Alexandra; Mehrad, Borna

    2016-06-15

    Gram-negative bacterial pneumonia is a common and dangerous infection with diminishing treatment options due to increasing antibiotic resistance among causal pathogens. The mononuclear phagocyte system is a heterogeneous group of leukocytes composed of tissue-resident macrophages, dendritic cells, and monocyte-derived cells that are critical in defense against pneumonia, but mechanisms that regulate their maintenance and function during infection are poorly defined. M-CSF has myriad effects on mononuclear phagocytes but its role in pneumonia is unknown. We therefore tested the hypothesis that M-CSF is required for mononuclear phagocyte-mediated host defenses during bacterial pneumonia in a murine model of infection. Genetic deletion or immunoneutralization of M-CSF resulted in reduced survival, increased bacterial burden, and greater lung injury. M-CSF was necessary for the expansion of lung mononuclear phagocytes during infection but did not affect the number of bone marrow or blood monocytes, proliferation of precursors, or recruitment of leukocytes to the lungs. In contrast, M-CSF was essential to survival and antimicrobial functions of both lung and liver mononuclear phagocytes during pneumonia, and its absence resulted in bacterial dissemination to the liver and hepatic necrosis. We conclude that M-CSF is critical to host defenses against bacterial pneumonia by mediating survival and antimicrobial functions of mononuclear phagocytes in the lungs and liver. PMID:27183631

  13. Differential control of pre-invasive and post-invasive antibacterial defense by the Arabidopsis circadian clock.

    Science.gov (United States)

    Korneli, Christin; Danisman, Selahattin; Staiger, Dorothee

    2014-09-01

    Plants show a suite of inducible defense responses against bacterial pathogens. Here we investigate in detail the effect of the circadian clock on these reactions in Arabidopsis thaliana. The magnitude of immune responses elicited by flg22, by virulent and by avirulent Pseudomonas syringae strains depends on the time of day of inoculation. The oxidative burst is stronger when flg22 is infiltrated in the morning in wild-type plants but not in the arrhythmic clock mutant lux arrhythmo/phytoclock1 (pcl1), and thus is controlled by the endogenous clock. Similarly, when bacteria are syringe-infiltrated into the leaf, defense gene induction is higher and bacterial growth is suppressed more strongly after morning inoculation in wild-type but not in pcl1 plants. Furthermore, cell death associated with the hypersensitive response was found to be under clock control. Notably, the clock effect depends on the mode of infection: upon spray inoculation onto the leaf surface, defense gene induction is higher and bacterial growth is suppressed more strongly upon evening inoculation. This different phasing of pre-invasive and post-invasive defense relates to clock-regulated stomatal movement. In particular, TIME FOR COFFEE may impact pathogen defense via clock-regulated stomata movement apart from its known role in time-of-day-dependent jasmonate responses. Taken together, these data highlight the importance of the circadian clock for the control of different immune responses at distinct times of the day. PMID:24974385

  14. Relative roles of the cellular and humoral responses in the Drosophila host defense against three gram-positive bacterial infections.

    Directory of Open Access Journals (Sweden)

    Nadine T Nehme

    Full Text Available BACKGROUND: Two NF-kappaB signaling pathways, Toll and immune deficiency (imd, are required for survival to bacterial infections in Drosophila. In response to septic injury, these pathways mediate rapid transcriptional activation of distinct sets of effector molecules, including antimicrobial peptides, which are important components of a humoral defense response. However, it is less clear to what extent macrophage-like hemocytes contribute to host defense. METHODOLOGY/PRINCIPAL FINDINGS: In order to dissect the relative importance of humoral and cellular defenses after septic injury with three different gram-positive bacteria (Micrococcus luteus, Enterococcus faecalis, Staphylococcus aureus, we used latex bead pre-injection to ablate macrophage function in flies wildtype or mutant for various Toll and imd pathway components. We found that in all three infection models a compromised phagocytic system impaired fly survival--independently of concomitant Toll or imd pathway activation. Our data failed to confirm a role of the PGRP-SA and GNBP1 Pattern Recognition Receptors for phagocytosis of S. aureus. The Drosophila scavenger receptor Eater mediates the phagocytosis by hemocytes or S2 cells of E. faecalis and S. aureus, but not of M. luteus. In the case of M. luteus and E. faecalis, but not S. aureus, decreased survival due to defective phagocytosis could be compensated for by genetically enhancing the humoral immune response. CONCLUSIONS/SIGNIFICANCE: Our results underscore the fundamental importance of both cellular and humoral mechanisms in Drosophila immunity and shed light on the balance between these two arms of host defense depending on the invading pathogen.

  15. Stealth Proteins: In Silico Identification of a Novel Protein Family Rendering Bacterial Pathogens Invisible to Host Immune Defense.

    Directory of Open Access Journals (Sweden)

    2005-11-01

    Full Text Available There are a variety of bacterial defense strategies to survive in a hostile environment. Generation of extracellular polysaccharides has proved to be a simple but effective strategy against the host's innate immune system. A comparative genomics approach led us to identify a new protein family termed Stealth, most likely involved in the synthesis of extracellular polysaccharides. This protein family is characterized by a series of domains conserved across phylogeny from bacteria to eukaryotes. In bacteria, Stealth (previously characterized as SacB, XcbA, or WefC is encoded by subsets of strains mainly colonizing multicellular organisms, with evidence for a protective effect against the host innate immune defense. More specifically, integrating all the available information about Stealth proteins in bacteria, we propose that Stealth is a D-hexose-1-phosphoryl transferase involved in the synthesis of polysaccharides. In the animal kingdom, Stealth is strongly conserved across evolution from social amoebas to simple and complex multicellular organisms, such as Dictyostelium discoideum, hydra, and human. Based on the occurrence of Stealth in most Eukaryotes and a subset of Prokaryotes together with its potential role in extracellular polysaccharide synthesis, we propose that metazoan Stealth functions to regulate the innate immune system. Moreover, there is good reason to speculate that the acquisition and spread of Stealth could be responsible for future epidemic outbreaks of infectious diseases caused by a large variety of eubacterial pathogens. Our in silico identification of a homologous protein in the human host will help to elucidate the causes of Stealth-dependent virulence. At a more basic level, the characterization of the molecular and cellular function of Stealth proteins may shed light on fundamental mechanisms of innate immune defense against microbial invasion.

  16. Stealth proteins: in silico identification of a novel protein family rendering bacterial pathogens invisible to host immune defense.

    Directory of Open Access Journals (Sweden)

    Peter Sperisen

    2005-11-01

    Full Text Available There are a variety of bacterial defense strategies to survive in a hostile environment. Generation of extracellular polysaccharides has proved to be a simple but effective strategy against the host's innate immune system. A comparative genomics approach led us to identify a new protein family termed Stealth, most likely involved in the synthesis of extracellular polysaccharides. This protein family is characterized by a series of domains conserved across phylogeny from bacteria to eukaryotes. In bacteria, Stealth (previously characterized as SacB, XcbA, or WefC is encoded by subsets of strains mainly colonizing multicellular organisms, with evidence for a protective effect against the host innate immune defense. More specifically, integrating all the available information about Stealth proteins in bacteria, we propose that Stealth is a D-hexose-1-phosphoryl transferase involved in the synthesis of polysaccharides. In the animal kingdom, Stealth is strongly conserved across evolution from social amoebas to simple and complex multicellular organisms, such as Dictyostelium discoideum, hydra, and human. Based on the occurrence of Stealth in most Eukaryotes and a subset of Prokaryotes together with its potential role in extracellular polysaccharide synthesis, we propose that metazoan Stealth functions to regulate the innate immune system. Moreover, there is good reason to speculate that the acquisition and spread of Stealth could be responsible for future epidemic outbreaks of infectious diseases caused by a large variety of eubacterial pathogens. Our in silico identification of a homologous protein in the human host will help to elucidate the causes of Stealth-dependent virulence. At a more basic level, the characterization of the molecular and cellular function of Stealth proteins may shed light on fundamental mechanisms of innate immune defense against microbial invasion.

  17. Relationships among CFTR expression, HCO3- secretion, and host defense may inform gene- and cell-based cystic fibrosis therapies.

    Science.gov (United States)

    Shah, Viral S; Ernst, Sarah; Tang, Xiao Xiao; Karp, Philip H; Parker, Connor P; Ostedgaard, Lynda S; Welsh, Michael J

    2016-05-10

    Cystic fibrosis (CF) is caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) anion channel. Airway disease is the major source of morbidity and mortality. Successful implementation of gene- and cell-based therapies for CF airway disease requires knowledge of relationships among percentages of targeted cells, levels of CFTR expression, correction of electrolyte transport, and rescue of host defense defects. Previous studies suggested that, when ∼10-50% of airway epithelial cells expressed CFTR, they generated nearly wild-type levels of Cl(-) secretion; overexpressing CFTR offered no advantage compared with endogenous expression levels. However, recent discoveries focused attention on CFTR-mediated HCO3 (-) secretion and airway surface liquid (ASL) pH as critical for host defense and CF pathogenesis. Therefore, we generated porcine airway epithelia with varying ratios of CF and wild-type cells. Epithelia with a 50:50 mix secreted HCO3 (-) at half the rate of wild-type epithelia. Likewise, heterozygous epithelia (CFTR(+/-) or CFTR(+/∆F508)) expressed CFTR and secreted HCO3 (-) at ∼50% of wild-type values. ASL pH, antimicrobial activity, and viscosity showed similar relationships to the amount of CFTR. Overexpressing CFTR increased HCO3 (-) secretion to rates greater than wild type, but ASL pH did not exceed wild-type values. Thus, in contrast to Cl(-) secretion, the amount of CFTR is rate-limiting for HCO3 (-) secretion and for correcting host defense abnormalities. In addition, overexpressing CFTR might produce a greater benefit than expressing CFTR at wild-type levels when targeting small fractions of cells. These findings may also explain the risk of airway disease in CF carriers. PMID:27114540

  18. EBAG9 modulates host immune defense against tumor formation and metastasis by regulating cytotoxic activity of T lymphocytes

    OpenAIRE

    Miyazaki, T; Ikeda, K.; Horie-Inoue, K.; Kondo, T; Takahashi, S.; Inoue, S.

    2014-01-01

    Estrogen receptor-binding fragment-associated antigen 9 (EBAG9) is a primary estrogen-responsive gene that we previously identified in MCF-7 breast cancer cells using the CpG genomic binding-site cloning technique. The expression of EBAG9 protein is often upregulated in malignant tumors, suggesting that this protein is involved in cancer pathophysiology. In the present study, we investigated the role of EBAG9 in host defense against implanted tumors in Ebag9-knockout (Ebag9KO) mice. MB-49 mou...

  19. Effects of parasite pressure on parasite mortality and reproductive output in a rodent-flea system: inferring host defense trade-offs.

    Science.gov (United States)

    Warburton, Elizabeth M; Kam, Michael; Bar-Shira, Enav; Friedman, Aharon; Khokhlova, Irina S; Koren, Lee; Asfur, Mustafa; Geffen, Eli; Kiefer, Daniel; Krasnov, Boris R; Degen, A Allan

    2016-09-01

    Evaluating host resistance via parasite fitness helps place host-parasite relationships within evolutionary and ecological contexts; however, few studies consider both these processes simultaneously. We investigated how different levels of parasite pressure affect parasite mortality and reproductive success in relationship to host defense efforts, using the rodent Gerbillus nanus and the flea Xenopsylla conformis as a host-parasite system. Fifteen immune-naïve male rodents were infested with 20, 50, or 100 fleas for four weeks. During this time number of new imagoes produced per adult flea (our flea reproductive output metric), flea mortality, and change in circulating anti-flea immunoglobulin G (our measure of adaptive immune defense) were monitored. Three hypotheses guided this work: (1) increasing parasite pressure would heighten host defenses; (2) parasite mortality would increase and parasite reproductive output would decrease with increasing investment in host defense; and (3) hosts under high parasite pressure could invest in behavioral and/or immune responses. We predicted that at high infestation levels (a) parasite mortality would increase; (b) flea reproductive output per individual would decrease; and (c) host circulating anti-flea antibody levels would increase. The hypotheses were partially supported. Flea mortality significantly increased and flea reproductive output significantly decreased as flea pressure increased. Host adaptive immune defense did not significantly change with increasing flea pressure. Therefore, we inferred that investment in host behavioral defense, either alone or in combination with density-dependent effects, may be more efficient at increasing flea mortality and decreasing flea reproductive output than antibody production during initial infestation in this system. PMID:27130319

  20. Evidence for alteration of fungal endophyte community assembly by host defense compounds.

    Science.gov (United States)

    Saunders, Megan; Kohn, Linda Myra

    2009-01-01

    * Plant defense compounds are common stressors encountered by endophytes. Fungi readily evolve tolerance to these compounds, yet few studies have addressed the influence of intraspecific variation in defense compound production on endophyte colonization. We compared the influence of defense compound production on the composition of fungal endophyte communities in replicated field experiments. * Maize (Zea mays) produces benzoxazinoids (BXs), compounds with antifungal byproducts persistent in the environment. Fungi were isolated from leaf and root tissue of two maize genotypes that produce BXs, and a natural mutant that does not. Isolates representing the species recovered were tested for tolerance to 2-benzoxazolinone (BOA), a toxic BX byproduct. * In seedling roots and mature leaves, the community proportion with low BOA tolerance was significantly greater in BX nonproducers than producers. Mean isolation frequency of Fusarium species was up to 35 times higher in mature leaves of BX producers than nonproducers. * Fungal species with relatively high tolerance to BOA are more abundant in BX producing than BX nonproducing maize. Production of BXs may increase colonization by Fusarium species in maize, including agents of animal toxicosis and yield-reducing disease in maize. Overall, results indicate that production of defense compounds can significantly alter endophyte community assembly. PMID:19170900

  1. Host-pathogen interactions between the human innate immune system and Candida albicans - Understanding and modeling defense and evasion strategies

    Directory of Open Access Journals (Sweden)

    Sybille eDühring

    2015-06-01

    Full Text Available The diploid, polymorphic yeast Candida albicans is one of the most important humanpathogenic fungi. C. albicans can grow, proliferate and coexist as a commensal on or within thehuman host for a long time. Alterations in the host environment, however, can render C. albicansvirulent. In this review, we describe the immunological cross-talk between C. albicans and thehuman innate immune system. We give an overview in form of pairs of human defense strategiesincluding immunological mechanisms as well as general stressors such as nutrient limitation,pH, fever etc. and the corresponding fungal response and evasion mechanisms. FurthermoreComputational Systems Biology approaches to model and investigate these complex interactionare highlighted with a special focus on game-theoretical methods and agent-based models. Anoutlook on interesting questions to be tackled by Systems Biology regarding entangled defenseand evasion mechanisms is given.

  2. Emerging roles of the host defense peptide LL-37 in human cancer and its potential therapeutic applications.

    Science.gov (United States)

    Wu, William K K; Wang, Guangshun; Coffelt, Seth B; Betancourt, Aline M; Lee, Chung W; Fan, Daiming; Wu, Kaichun; Yu, Jun; Sung, Joseph J Y; Cho, Chi H

    2010-10-15

    Human cathelicidin LL-37, a host defense peptide derived from leukocytes and epithelial cells, plays a crucial role in innate and adaptive immunity. Not only does LL-37 eliminate pathogenic microbes directly but also modulates host immune responses. Emerging evidence from tumor biology studies indicates that LL-37 plays a prominent and complex role in carcinogenesis. Although overexpression of LL-37 has been implicated in the development or progression of many human malignancies, including breast, ovarian and lung cancers, LL-37 suppresses tumorigenesis in gastric cancer. These data are beginning to unveil the intricate and contradictory functions of LL-37. The reasons for the tissue-specific function of LL-37 in carcinogenesis remain to be elucidated. Here, we review the relationship between LL-37, its fragments and cancer progression as well as discuss the potential therapeutic implications of targeting this peptide. PMID:20521250

  3. Haematophagous arthropod saliva and host defense system: a tale of tear and blood

    Directory of Open Access Journals (Sweden)

    Andrade Bruno B.

    2005-01-01

    Full Text Available The saliva from blood-feeding arthropod vectors is enriched with molecules that display diverse functions that mediate a successful blood meal. They function not only as weapons against host's haemostatic, inflammatory and immune responses but also as important tools to pathogen establishment. Parasites, virus and bacteria taking advantage of vectors' armament have adapted to facilitate their entry in the host. Today, many salivary molecules have been identified and characterized as new targets to the development of future vaccines. Here we focus on current information on vector's saliva and the molecules responsible to modify host's hemostasis and immune response, also regarding their role in disease transmission.

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

    OpenAIRE

    Miguel A. Mata; 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.

    2011-01-01

    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 occu...

  5. Chemical Inhibition of RNA Viruses Reveals REDD1 as Host Defense Factor

    OpenAIRE

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

    2011-01-01

    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 reverted NS1-mediated inhibition of host gene expression. A counter-screen for suppression of influenza virus cytotoxicity identified naphthalimides that inhibited replication of influenza virus and vesicular stomatitis virus. The mechanism of action was throu...

  6. Toxoplasma gondii TgIST co-opts host chromatin repressors dampening STAT1-dependent gene regulation and IFN-γ-mediated host defenses.

    Science.gov (United States)

    Gay, Gabrielle; Braun, Laurence; Brenier-Pinchart, Marie-Pierre; Vollaire, Julien; Josserand, Véronique; Bertini, Rose-Laurence; Varesano, Aurélie; Touquet, Bastien; De Bock, Pieter-Jan; Coute, Yohann; Tardieux, Isabelle; Bougdour, Alexandre; Hakimi, Mohamed-Ali

    2016-08-22

    An early hallmark of Toxoplasma gondii infection is the rapid control of the parasite population by a potent multifaceted innate immune response that engages resident and homing immune cells along with pro- and counter-inflammatory cytokines. In this context, IFN-γ activates a variety of T. gondii-targeting activities in immune and nonimmune cells but can also contribute to host immune pathology. T. gondii has evolved mechanisms to timely counteract the host IFN-γ defenses by interfering with the transcription of IFN-γ-stimulated genes. We now have identified TgIST (T. gondii inhibitor of STAT1 transcriptional activity) as a critical molecular switch that is secreted by intracellular parasites and traffics to the host cell nucleus where it inhibits STAT1-dependent proinflammatory gene expression. We show that TgIST not only sequesters STAT1 on dedicated loci but also promotes shaping of a nonpermissive chromatin through its capacity to recruit the nucleosome remodeling deacetylase (NuRD) transcriptional repressor. We found that during mice acute infection, TgIST-deficient parasites are rapidly eliminated by the homing Gr1(+) inflammatory monocytes, thus highlighting the protective role of TgIST against IFN-γ-mediated killing. By uncovering TgIST functions, this study brings novel evidence on how T. gondii has devised a molecular weapon of choice to take control over a ubiquitous immune gene expression mechanism in metazoans, as a way to promote long-term parasitism. PMID:27503074

  7. Host Defense and the Airway Epithelium: Frontline Responses That Protect against Bacterial Invasion and Pneumonia

    OpenAIRE

    Nicholas A. Eisele; Anderson, Deborah M.

    2011-01-01

    Airway epithelial cells are the first line of defense against invading microbes, and they protect themselves through the production of carbohydrate and protein matrices concentrated with antimicrobial products. In addition, they act as sentinels, expressing pattern recognition receptors that become activated upon sensing bacterial products and stimulate downstream recruitment and activation of immune cells which clear invading microbes. Bacterial pathogens that successfully colonize the lungs...

  8. Review: The intersection of surfactant homeostasis and innate host defense of the lung: lessons from newborn infants.

    Science.gov (United States)

    Whitsett, Jeffrey A

    2010-06-01

    The study of pulmonary surfactant, directed towards prevention and treatment of respiratory distress syndrome in preterm infants, led to the identification of novel proteins/genes that determine the synthesis, packaging, secretion, function, and catabolism of alveolar surfactant. The surfactant proteins, SP-A, SP-B, SP-C, and SP-D, and the surfactant lipid associated transporter, ABCA3, play critical roles in surfactant homeostasis. The study of their structure and function provided insight into a system that integrates the biophysical need to reduce surface tension in the alveoli and the innate host defenses required to maintain pulmonary structure and function after birth. Alveolar homeostasis depends on the intrinsic, multifunctional structures of the surfactant-associated proteins and the shared transcriptional regulatory modules that determine both the expression of genes involved in surfactant production as well as those critical for host defense. Identification of the surfactant proteins and the elucidation of the genetic networks regulating alveolar homeostasis have provided the basis for understanding and diagnosing rare and common pulmonary disorders, including respiratory distress syndrome, inherited disorders of surfactant homeostasis, and pulmonary alveolar proteinosis. PMID:20351134

  9. Important role for Toll-like receptor 9 in host defense against meningococcal sepsis

    DEFF Research Database (Denmark)

    Sjölinder, Hong; Mogensen, Trine; Kilian, Mogens;

    2008-01-01

    Neisseria meningitidis is a leading cause of meningitis and sepsis. The pathogenesis of meningococcal disease is determined by both bacterial virulence factors and the host inflammatory response. Toll-like receptors (TLRs) are prominent activators of the inflammatory response, and TLR2, -4, and -9...... have been reported to be involved in the host response to N. meningitidis. While TLR4 has been suggested to play an important role in early containment of infection, the roles of TLR2 and TLR9 in meningococcal disease are not well described. Using a model for meningococcal sepsis, we report that TLR9...

  10. Increased host investment in extrafloral nectar (EFN improves the efficiency of a mutualistic defensive service.

    Directory of Open Access Journals (Sweden)

    Marcia González-Teuber

    Full Text Available Extrafloral nectar (EFN plays an important role as plant indirect defence through the attraction of defending ants. Like all rewards produced in the context of a mutualism, however, EFN is in danger of being exploited by non-ant consumers that do not defend the plant against herbivores. Here we asked whether plants, by investing more in EFN, can improve their indirect defence, or rather increase the risk of losing this investment to EFN thieves. We used the obligate plant-ant Acacia-Pseudomyrmex system and examined experimentally in the field during the dry and the rainy seasons how variations in EFN secretion are related to (i ant activity, to (ii the ant-mediated defence against herbivores and (iii the exploitation of EFN by non-ant consumers. Extrafloral investment enhanced ant recruitment and was positively related to the ant mediated defence against herbivores. The ant-mediated protection from exploiters also increased in proportion to the nectar sugar concentration. Although the daily peak of EFN production coincided with the highest activity of EFN thieves, Pseudomyrmex ferrugineus ants protected this resource effectively from exploiters. Nevertheless, the defensive effects by ants differed among seasons. During the dry season, plants grew slower and secreted more EFN than in the rainy season, and thus, experienced a higher level of ant-mediated indirect defence. Our results show that an increased plant investment in an indirect defence trait can improve the resulting defensive service against both herbivores and exploiters. EFN secretion by obligate ant-plants represents a defensive trait for which the level of investment correlates positively with the beneficial effects obtained.

  11. In vitro and ex vivo effects of cyclosporin A on phagocytic host defenses against Aspergillus fumigatus.

    OpenAIRE

    Roilides, E.; Robinson, T.; T Sein; Pizzo, P A; Walsh, T J

    1994-01-01

    Because cyclosporin A (CsA) is extensively used as an immunosuppressive agent, its effects on phagocytic defenses against Aspergillus fumigatus were studied in vitro and ex vivo. After incubation with 10 to 250 ng of CsA per ml at 37 degrees C for 60 min, polymorphonuclear leukocytes (PMNs) exhibited unaltered superoxide anion (O2-) production in response to phorbol myristate acetate and N-formylmethionyl leucyl phenylalanine, whereas > or = 500 ng/ml significantly suppressed it (P < 0.01). M...

  12. Interferon-inducible CXC chemokines directly contribute to host defense against inhalational anthrax in a murine model of infection.

    Directory of Open Access Journals (Sweden)

    Matthew A Crawford

    Full Text Available Chemokines have been found to exert direct, defensin-like antimicrobial activity in vitro, suggesting that, in addition to orchestrating cellular accumulation and activation, chemokines may contribute directly to the innate host response against infection. No observations have been made, however, demonstrating direct chemokine-mediated promotion of host defense in vivo. Here, we show that the murine interferon-inducible CXC chemokines CXCL9, CXCL10, and CXCL11 each exert direct antimicrobial effects in vitro against Bacillus anthracis Sterne strain spores and bacilli including disruptions in spore germination and marked reductions in spore and bacilli viability as assessed using CFU determination and a fluorometric assay of metabolic activity. Similar chemokine-mediated antimicrobial activity was also observed against fully virulent Ames strain spores and encapsulated bacilli. Moreover, antibody-mediated neutralization of these CXC chemokines in vivo was found to significantly increase host susceptibility to pulmonary B. anthracis infection in a murine model of inhalational anthrax with disease progression characterized by systemic bacterial dissemination, toxemia, and host death. Neutralization of the shared chemokine receptor CXCR3, responsible for mediating cellular recruitment in response to CXCL9, CXCL10, and CXCL11, was not found to increase host susceptibility to inhalational anthrax. Taken together, our data demonstrate a novel, receptor-independent antimicrobial role for the interferon-inducible CXC chemokines in pulmonary innate immunity in vivo. These data also support an immunomodulatory approach for effectively treating and/or preventing pulmonary B. anthracis infection, as well as infections caused by pathogenic and potentially, multi-drug resistant bacteria including other spore-forming organisms.

  13. Antipredator defense of biological control agent Oxyops vitiosa is mediated by plant volatiles sequestered from the host plant Melaleuca quinquenervia.

    Science.gov (United States)

    Wheeler, G S; Massey, L M; Southwell, I A

    2002-02-01

    The weevil Oxyops vitiosa is an Australian species imported to Florida, USA, for the biological control of the invasive weed species Melaleuca quinquenervia. Larvae of this species feed on leaves of their host and produce a shiny orange secretion that covers the integument. When this secretion is applied at physiological concentrations to dog food bait, fire ant consumption and visitation are significantly reduced. Gas chromatographic analysis indicates that the larval secretion qualitatively and quantitatively resembles the terpenoid composition of the host foliage. When the combination of 10 major terpenoids from the O. vitiosa secretion was applied to dog food bait, fire ant consumption and visitation were reduced. When these 10 terpenoids were tested individually, the sesquiterpene viridiflorol was the most active component in decreasing fire ant consumption. Fire ant visitation was initially (15 min after initiation of the study) decreased for dog food bait treated with viridiflorol and the monoterpenes 1,8-cineole and alpha-terpineol. Fire ants continued to avoid the bait treated with viridiflorol at 18 microg/mg dog food for up to 6 hr after the initiation of the experiment. Moreover, ants avoided bait treated with 1.8 microg/mg for up to 3 hr. The concentrations of viridiflorol, 1,8-cineole, and alpha-terpineol in larval washes were about twice that of the host foliage, suggesting that the larvae sequester these plant-derived compounds for defense against generalist predators. PMID:11925069

  14. Secretory leukocyte protease inhibitor (SLPI), a multifunctional protein in the host defense response.

    Science.gov (United States)

    Majchrzak-Gorecka, Monika; Majewski, Pawel; Grygier, Beata; Murzyn, Krzysztof; Cichy, Joanna

    2016-04-01

    Secretory leukocyte protease inhibitor (SLPI), a ∼12kDa nonglycosylated cationic protein, is emerging as an important regulator of innate and adaptive immunity and as a component of tissue regenerative programs. First described as an inhibitor of serine proteases such as neutrophil elastase, this protein is increasingly recognized as a molecule that benefits the host via its anti-proteolytic, anti-microbial and immunomodulatory activities. Here, we discuss the diverse functions of SLPI. Moreover, we review several novel layers of SLPI-mediated control that protect the host from excessive/dysregulated inflammation typical of infectious, allergic and autoinflammatory diseases and that support healing responses through affecting cell proliferation, differentiation and apoptosis. PMID:26718149

  15. Antimicrobial Metabolites Produced by Epibiotic Bacteria: Their Role in Microbial Competition and Host Defense

    OpenAIRE

    Gil-Turnes, Maria S.

    1988-01-01

    Although many bacteria have the ability to produce antimicrobial compounds in culture, it is not clear wheather bacterial metabolites have an adaptive function in microbial competition. The work described in this thesis represents a new approach to microbial chemical ecology. Three examples are described where antimicrobial compounds produced by epibiotic bacteria protect the host from encroachment by other microorganisms. Embryos of the caridean shrimp Palaemon macrodactylus are p...

  16. Unmasking host and microbial strategies in the Agrobacterium-plant defense tango

    OpenAIRE

    Hwang, Elizabeth E.; Wang, Melinda B.; Bravo, Janis E.; Banta, Lois M

    2015-01-01

    Coevolutionary forces drive adaptation of both plant-associated microbes and their hosts. Eloquently captured in the Red Queen Hypothesis, the complexity of each plant–pathogen relationship reflects escalating adversarial strategies, but also external biotic and abiotic pressures on both partners. Innate immune responses are triggered by highly conserved pathogen-associated molecular patterns, or PAMPs, that are harbingers of microbial presence. Upon cell surface receptor-mediated recognition...

  17. Ticks and tick-borne pathogens at the cutaneous interface: host defenses, tick countermeasures, and a suitable environment for pathogen establishment.

    Science.gov (United States)

    Wikel, Stephen

    2013-01-01

    Ticks are unique among hematophagous arthropods by continuous attachment to host skin and blood feeding for days; complexity and diversity of biologically active molecules differentially expressed in saliva of tick species; their ability to modulate the host defenses of pain and itch, hemostasis, inflammation, innate and adaptive immunity, and wound healing; and, the diverse array of infectious agents they transmit. All of these interactions occur at the cutaneous interface in a complex sequence of carefully choreographed host defense responses and tick countermeasures resulting in an environment that facilitates successful blood feeding and establishment of tick-borne infectious agents within the host. Here, we examine diverse patterns of tick attachment to host skin, blood feeding mechanisms, salivary gland transcriptomes, bioactive molecules in tick saliva, timing of pathogen transmission, and host responses to tick bite. Ticks engage and modulate cutaneous and systemic immune defenses involving keratinocytes, natural killer cells, dendritic cells, T cell subpopulations (Th1, Th2, Th17, Treg), B cells, neutrophils, mast cells, basophils, endothelial cells, cytokines, chemokines, complement, and extracellular matrix. A framework is proposed that integrates tick induced changes of skin immune effectors with their ability to respond to tick-borne pathogens. Implications of these changes are addressed. What are the consequences of tick modulation of host cutaneous defenses? Does diversity of salivary gland transcriptomes determine differential modulation of host inflammation and immune defenses and therefore, in part, the clades of pathogens effectively transmitted by different tick species? Do ticks create an immunologically modified cutaneous environment that enhances specific pathogen establishment? Can tick saliva molecules be used to develop vaccines that block pathogen transmission? PMID:24312085

  18. Ticks and tick-borne pathogens at the cutaneous interface: host defenses, tick countermeasures, and a suitable environment for pathogen establishment

    Directory of Open Access Journals (Sweden)

    Stephen eWikel

    2013-11-01

    Full Text Available Ticks are unique among hematophagous arthropods by continuous attachment to host skin and blood feeding for days; complexity and diversity of biologically active molecules differentially expressed in saliva of tick species; their ability to modulate the host defenses of pain and itch, hemostasis, inflammation, innate and adaptive immunity, and wound healing; and, the diverse array of infectious agents they transmit. All of these interactions occur at the cutaneous interface in a complex sequence of carefully choreographed host defense responses and tick countermeasures resulting in an environment that facilitates successful blood feeding and establishment of tick-borne infectious agents within the host. Here, we examine diverse patterns of tick attachment to host skin, blood feeding mechanisms, salivary gland transcriptomes, bioactive molecules in tick saliva, timing of pathogen transmission, and host responses to tick bite. Ticks engage and modulate cutaneous and systemic immune defenses involving keratinocytes, natural killer cells, dendritic cells, T cell subpopulations (Th1, Th2, Th17, Treg , B cells, neutrophils, mast cells, basophils, endothelial cells, cytokines, chemokines, complement, and extracellular matrix. A framework is proposed that integrates tick induced changes of skin immune effectors with their ability to respond to tick-borne pathogens. Implications of these changes are addressed. What are the consequences of tick modulation of host cutaneous defenses? Does diversity of salivary gland transcriptomes determine differential modulation of host inflammation and immune defenses and therefore, in part, the clades of pathogens effectively transmitted by different tick species? Do ticks create an immunologically modified cutaneous environment that enhances specific pathogen establishment? Can tick saliva molecules be used to develop vaccines that block pathogen transmission?

  19. Exploration of Phage-Host Interactions in Fish Pathogen Vibrio anguillarum and Anti-Phage Defense Strategies

    DEFF Research Database (Denmark)

    Tan, Demeng

    repress ompK expression. It was demonstrated that QS controls the choice of anti-phage defense strategies in the V. anguillarum strain PF430-3, suggesting the presence of dynamic, temporary adaptations to phage infection pressure, while still securing the ability to produce a functional OmpK receptor. In...... bacterial pathogenicity development. Therefore, successful application of phage therapy in the treatment of vibriosis requires a detailed understanding of phage-host interactions, especially with regards to anti-phage defense mechanisms in the host. Part I. As a first approach, 24 V. anguillarum and 13...... conclusion, this thesis provides a first insight into the dynamic vibriophage-host interactions, indicating the complexity of phage therapy in the treatment of vibriosis, regarding the evolution of anti-phage defense mechanisms, gene regulation, quorum sensing, biofilm formation, as well as pathogenesis...

  20. NLRC4-driven production of IL-1β discriminates between pathogenic and commensal bacteria and promotes host intestinal defense.

    Science.gov (United States)

    Franchi, Luigi; Kamada, Nobuhiko; Nakamura, Yuumi; Burberry, Aaron; Kuffa, Peter; Suzuki, Shiho; Shaw, Michael H; Kim, Yun-Gi; Núñez, Gabriel

    2012-05-01

    Intestinal phagocytes transport oral antigens and promote immune tolerance, but their role in innate immune responses remains unclear. Here we found that intestinal phagocytes were anergic to ligands for Toll-like receptors (TLRs) or commensals but constitutively expressed the precursor to interleukin 1β (pro-IL-1β). After infection with pathogenic Salmonella or Pseudomonas, intestinal phagocytes produced mature IL-1β through the NLRC4 inflammasome but did not produce tumor necrosis factor (TNF) or IL-6. BALB/c mice deficient in NLRC4 or the IL-1 receptor were highly susceptible to orogastric but not intraperitoneal infection with Salmonella. That enhanced lethality was preceded by impaired expression of endothelial adhesion molecules, lower neutrophil recruitment and poor intestinal pathogen clearance. Thus, NLRC4-dependent production of IL-1β by intestinal phagocytes represents a specific response that discriminates pathogenic bacteria from commensal bacteria and contributes to host defense in the intestine. PMID:22484733

  1. NLRC4-driven interleukin-1β production discriminates between pathogenic and commensal bacteria and promotes host intestinal defense

    Science.gov (United States)

    Franchi, Luigi; Kamada, Nobuhiko; Nakamura, Yuumi; Burberry, Aaron; Kuffa, Peter; Suzuki, Shiho; Shaw, Michael H.; Kim, Yun-Gi; Núñez, Gabriel

    2012-01-01

    Intestinal phagocytes transport oral antigens and promote immune tolerance, but their role in innate immune responses remains unclear. Here we report that intestinal phagocytes are anergic to Toll-like receptor ligands or commensals, but constitutively express pro-interleukin-1β (proIL-1β). Upon infection with pathogenic Salmonella or Pseudomonas, intestinal phagocytes produce mature IL-1β through the NLRC4 inflammasome, but not tumor necrosis factor or IL-6. Mice deficient in NLRC4 or IL-1 receptor on a Balb/c background were highly susceptible to orogastric but not intraperitoneal infection with Salmonella. Increased lethality was preceded by impaired expression of endothelial adhesion molecules, lower neutrophil recruitment, and poor intestinal pathogen clearance. Thus, NLRC4-dependent IL-1β production by intestinal phagocytes represents a specific response discriminating pathogenic from commensal bacteria and contributes to host defense in the intestine. PMID:22484733

  2. Neuroinflammatory contributions to pain after SCI: roles for central glial mechanisms and nociceptor-mediated host defense.

    Science.gov (United States)

    Walters, Edgar T

    2014-08-01

    Neuropathic pain after spinal cord injury (SCI) is common, often intractable, and can be severely debilitating. A number of mechanisms have been proposed for this pain, which are discussed briefly, along with methods for revealing SCI pain in animal models, such as the recently applied conditioned place preference test. During the last decade, studies of animal models have shown that both central neuroinflammation and behavioral hypersensitivity (indirect reflex measures of pain) persist chronically after SCI. Interventions that reduce neuroinflammation have been found to ameliorate pain-related behavior, such as treatment with agents that inhibit the activation states of microglia and/or astroglia (including IL-10, minocycline, etanercept, propentofylline, ibudilast, licofelone, SP600125, carbenoxolone). Reversal of pain-related behavior has also been shown with disruption by an inhibitor (CR8) and/or genetic deletion of cell cycle-related proteins, deletion of a truncated receptor (trkB.T1) for brain-derived neurotrophic factor (BDNF), or reduction by antisense knockdown or an inhibitor (AMG9810) of the activity of channels (TRPV1 or Nav1.8) important for electrical activity in primary nociceptors. Nociceptor activity is known to drive central neuroinflammation in peripheral injury models, and nociceptors appear to be an integral component of host defense. Thus, emerging results suggest that spinal and systemic effects of SCI can activate nociceptor-mediated host defense responses that interact via neuroinflammatory signaling with complex central consequences of SCI to drive chronic pain. This broader view of SCI-induced neuroinflammation suggests new targets, and additional complications, for efforts to develop effective treatments for neuropathic SCI pain. PMID:25017887

  3. Pseudomonas fluorescens induces strain-dependent and strain-independent host plant responses in defense networks, primary metabolism and photosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Pelletier, Dale A [ORNL; Morrell-Falvey, Jennifer L [ORNL; Karve, Abhijit A [ORNL; Lu, Tse-Yuan S [ORNL; Tschaplinski, Timothy J [ORNL; Tuskan, Gerald A [ORNL; Chen, Jay [ORNL; Martin, Madhavi Z [ORNL; Jawdy, Sara [ORNL; Weston, David [ORNL; Doktycz, Mitchel John [ORNL; Schadt, Christopher Warren [ORNL

    2012-01-01

    Colonization of plants by nonpathogenic Pseudomonas fluorescens strains can confer enhanced defense capacity against a broad spectrum of pathogens. Few studies, however, have linked defense pathway regulation to primary metabolism and physiology. In this study, physiological data, metabolites, and transcript profiles are integrated to elucidate how molecular networks initiated at the root-microbe interface influence shoot metabolism and whole-plant performance. Experiments with Arabidopsis thaliana were performed using the newly identified P. fluorescens GM30 or P. fluorescens Pf-5 strains. Co-expression networks indicated that Pf-5 and GM30 induced a subnetwork specific to roots enriched for genes participating in RNA regulation, protein degradation, and hormonal metabolism. In contrast, only GM30 induced a subnetwork enriched for calcium signaling, sugar and nutrient signaling, and auxin metabolism, suggesting strain dependence in network architecture. In addition, one subnetwork present in shoots was enriched for genes in secondary metabolism, photosynthetic light reactions, and hormone metabolism. Metabolite analysis indicated that this network initiated changes in carbohydrate and amino acid metabolism. Consistent with this, we observed strain-specific responses in tryptophan and phenylalanine abundance. Both strains reduced host plant carbon gain and fitness, yet provided a clear fitness benefit when plants were challenged with the pathogen P. syringae DC3000.

  4. Localization and developmental expression of two chicken host defense peptides: cathelicidin-2 and avian β-defensin 9.

    Science.gov (United States)

    Cuperus, Tryntsje; van Dijk, Albert; Dwars, R Marius; Haagsman, Henk P

    2016-08-01

    In the first weeks of life young chickens are highly susceptible to infectious diseases due to immaturity of the immune system. Little is known about the expression of host defense peptides (HDPs) during this period. In this study we examined the expression pattern of two chicken HDPs, the cathelicidin CATH-2 and the β-defensin AvBD9 by immunohistochemistry in a set of organs from embryonic day 12 until four weeks posthatch. AvBD9 was predominantly found in enteroendocrine cells throughout the intestine, the first report of in vivo HDP expression in this cell type, and showed stable expression levels during development. CATH-2 was exclusively found in heterophils which decreased after hatch in most of the examined organs including spleen, bursa and small intestine. In the lung CATH-2 expression was biphasic and peaked at the first day posthatch. In short, CATH-2 and AvBD9 appear to be expressed in cell types strategically located to respond to infectious stimuli, suggesting these peptides play a role in embryonic and early posthatch defense. PMID:26972737

  5. Candida albicans modulates host defense by biosynthesizing the pro-resolving mediator resolvin E1.

    Directory of Open Access Journals (Sweden)

    Eric J Haas-Stapleton

    Full Text Available Candida albicans is an opportunistic fungal pathogen of humans that resides commensally on epithelial surfaces, but can cause inflammation when pathogenic. Resolvins are a class of anti-inflammatory lipids derived from omega-3 polyunsaturated fatty acids (PUFA that attenuate neutrophil migration during the resolution phase of inflammation. In this report we demonstrate that C. albicans biosynthesizes resolvins that are chemically identical to those produced by human cells. In contrast to the trans-cellular biosynthesis of human Resolvin E1 (RvE1, RvE1 biosynthesis in C. albicans occurs in the absence of other cellular partners. C. albicans biosynthesis of RvE1 is sensitive to lipoxygenase and cytochrome P450 monoxygenase inhibitors. We show that 10nM RvE1 reduces neutrophil chemotaxis in response to IL-8; 1nM RvE1 enhanced phagocytosis of Candida by human neutrophils, as well as intracellular ROS generation and killing, while having no direct affect on neutrophil motility. In a mouse model of systemic candidiasis, RvE1 stimulated clearance of the fungus from circulating blood. These results reveal an inter-species chemical signaling system that modulates host immune functions and may play a role in balancing host carriage of commensal and pathogenic C. albicans.

  6. C5a of Cynoglossus semilaevis has anaphylatoxin-like properties and promotes antibacterial and antiviral defense.

    Science.gov (United States)

    Li, Mo-Fei; Hu, Yong-Hua

    2016-07-01

    Activation of the complement system leads to the cleavage of component factor C5 into C5a and C5b. C5a can induce chemotaxis and inflammatory responses in mammals. The function of C5a in fish is poorly understood. In this study, we report the identification and analysis of a C5 homologue, CsC5, from tongue sole (Cynoglossus semilaevis). CsC5 is composed of 1683 amino acid residues that include an anaphylatoxin homologous domain. Expression of CsC5 could be detected in a variety of tissues and was up-regulated by bacterial or viral pathogen infection. Purified recombinant CsC5a (rCsC5a) could bind to peripheral blood leukocytes (PBL) and stimulate PBL chemotaxis, proliferation, respiratory burst, acid phosphatase activity, and phagocytosis. Tongue sole administered rCsC5a exhibited enhanced resistance against bacterial and viral infections. These results indicate that CsC5a is an anaphylatoxin with a role in innate immune defense against bacterial and viral infections. PMID:26934108

  7. Role of Nucleotide-Binding Oligomerization Domain-Containing (NOD 2 in Host Defense during Pneumococcal Pneumonia.

    Directory of Open Access Journals (Sweden)

    Tijmen J Hommes

    Full Text Available Streptococcus (S. pneumoniae is the most common causative pathogen in community-acquired pneumonia. Nucleotide-binding oligomerization domain-containing (NOD 2 is a pattern recognition receptor located in the cytosol of myeloid cells that is able to detect peptidoglycan fragments of S. pneumoniae. We here aimed to investigate the role of NOD2 in the host response during pneumococcal pneumonia. Phagocytosis of S. pneumoniae was studied in NOD2 deficient (Nod2-/- and wild-type (Wt alveolar macrophages and neutrophils in vitro. In subsequent in vivo experiments Nod2-/- and Wt mice were inoculated with serotype 2 S. pneumoniae (D39, an isogenic capsule locus deletion mutant (D39Δcps or serotype 3 S. pneumoniae (6303 via the airways, and bacterial growth and dissemination and the lung inflammatory response were evaluated. Nod2-/- alveolar macrophages and blood neutrophils displayed a reduced capacity to internalize pneumococci in vitro. During pneumonia caused by S. pneumoniae D39 Nod2-/- mice were indistinguishable from Wt mice with regard to bacterial loads in lungs and distant organs, lung pathology and neutrophil recruitment. While Nod2-/- and Wt mice also had similar bacterial loads after infection with the more virulent S. pneumoniae 6303 strain, Nod2-/- mice displayed a reduced bacterial clearance of the normally avirulent unencapsulated D39Δcps strain. These results suggest that NOD2 does not contribute to host defense during pneumococcal pneumonia and that the pneumococcal capsule impairs recognition of S. pneumoniae by NOD2.

  8. P58(IPK: a novel "CIHD" member of the host innate defense response against pathogenic virus infection.

    Directory of Open Access Journals (Sweden)

    Alan G Goodman

    2009-05-01

    Full Text Available To support their replication, viruses take advantage of numerous cellular factors and processes. Recent large-scale screens have identified hundreds of such factors, yet little is known about how viruses exploit any of these. Influenza virus infection post-translationally activates P58(IPK, a cellular inhibitor of the interferon-induced, dsRNA-activated eIF2alpha kinase, PKR. Here, we report that infection of P58(IPK knockout mice with influenza virus resulted in increased lung pathology, immune cell apoptosis, PKR activation, and mortality. Analysis of lung transcriptional profiles, including those induced by the reconstructed 1918 pandemic virus, revealed increased expression of genes associated with the cell death, immune, and inflammatory responses. These experiments represent the first use of a mammalian infection model to demonstrate the role of P58(IPK in the antiviral response. Our results suggest that P58(IPK represents a new class of molecule, a cellular inhibitor of the host defense (CIHD, as P58(IPK is activated during virus infection to inhibit virus-induced apoptosis and inflammation to prolong host survival, even while prolonging viral replication.

  9. Toll-like receptor 2 impairs host defense in gram-negative sepsis caused by Burkholderia pseudomallei (Melioidosis.

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    W Joost Wiersinga

    2007-07-01

    Full Text Available BACKGROUND: Toll-like receptors (TLRs are essential in host defense against pathogens by virtue of their capacity to detect microbes and initiate the immune response. TLR2 is seen as the most important receptor for gram-positive bacteria, while TLR4 is regarded as the gram-negative TLR. Melioidosis is a severe infection caused by the gram-negative bacterium, Burkholderia pseudomallei, that is endemic in Southeast Asia. We aimed to characterize the expression and function of TLRs in septic melioidosis. METHODS AND FINDINGS: Patient studies: 34 patients with melioidosis demonstrated increased expression of CD14, TLR1, TLR2, and TLR4 on the cell surfaces of monocytes and granulocytes, and increased CD14, TLR1, TLR2, TLR4, LY96 (also known as MD-2, TLR5, and TLR10 mRNA levels in purified monocytes and granulocytes when compared with healthy controls. In vitro experiments: Whole-blood and alveolar macrophages obtained from TLR2 and TLR4 knockout (KO mice were less responsive to B. pseudomallei in vitro, whereas in the reverse experiment, transfection of HEK293 cells with either TLR2 or TLR4 rendered these cells responsive to this bacterium. In addition, the lipopolysaccharide (LPS of B. pseudomallei signals through TLR2 and not through TLR4. Mouse studies: Surprisingly, TLR4 KO mice were indistinguishable from wild-type mice with respect to bacterial outgrowth and survival in experimentally induced melioidosis. In contrast, TLR2 KO mice displayed a markedly improved host defenses as reflected by a strong survival advantage together with decreased bacterial loads, reduced lung inflammation, and less distant-organ injury. CONCLUSIONS: Patients with melioidosis displayed an up-regulation of multiple TLRs in peripheral blood monocytes and granulocytes. Although both TLR2 and TLR4 contribute to cellular responsiveness to B. pseudomallei in vitro, TLR2 detects the LPS of B. pseudomallei, and only TLR2 impacts on the immune response of the intact host in

  10. Exposure to electronic cigarettes impairs pulmonary anti-bacterial and anti-viral defenses in a mouse model.

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    Thomas E Sussan

    Full Text Available Electronic cigarettes (E-cigs have experienced sharp increases in popularity over the past five years due to many factors, including aggressive marketing, increased restrictions on conventional cigarettes, and a perception that E-cigs are healthy alternatives to cigarettes. Despite this perception, studies on health effects in humans are extremely limited and in vivo animal models have not been generated. Presently, we determined that E-cig vapor contains 7 x 10(11 free radicals per puff. To determine whether E-cig exposure impacts pulmonary responses in mice, we developed an inhalation chamber for E-cig exposure. Mice that were exposed to E-cig vapor contained serum cotinine concentrations that are comparable to human E-cig users. E-cig exposure for 2 weeks produced a significant increase in oxidative stress and moderate macrophage-mediated inflammation. Since, COPD patients are susceptible to bacterial and viral infections, we tested effects of E-cigs on immune response. Mice that were exposed to E-cig vapor showed significantly impaired pulmonary bacterial clearance, compared to air-exposed mice, following an intranasal infection with Streptococcus pneumonia. This defective bacterial clearance was partially due to reduced phagocytosis by alveolar macrophages from E-cig exposed mice. In response to Influenza A virus infection, E-cig exposed mice displayed increased lung viral titers and enhanced virus-induced illness and mortality. In summary, this study reports a murine model of E-cig exposure and demonstrates that E-cig exposure elicits impaired pulmonary anti-microbial defenses. Hence, E-cig exposure as an alternative to cigarette smoking must be rigorously tested in users for their effects on immune response and susceptibility to bacterial and viral infections.

  11. Exposure to electronic cigarettes impairs pulmonary anti-bacterial and anti-viral defenses in a mouse model.

    Science.gov (United States)

    Sussan, Thomas E; Gajghate, Sachin; Thimmulappa, Rajesh K; Ma, Jinfang; Kim, Jung-Hyun; Sudini, Kuladeep; Consolini, Nicola; Cormier, Stephania A; Lomnicki, Slawo; Hasan, Farhana; Pekosz, Andrew; Biswal, Shyam

    2015-01-01

    Electronic cigarettes (E-cigs) have experienced sharp increases in popularity over the past five years due to many factors, including aggressive marketing, increased restrictions on conventional cigarettes, and a perception that E-cigs are healthy alternatives to cigarettes. Despite this perception, studies on health effects in humans are extremely limited and in vivo animal models have not been generated. Presently, we determined that E-cig vapor contains 7 x 10(11) free radicals per puff. To determine whether E-cig exposure impacts pulmonary responses in mice, we developed an inhalation chamber for E-cig exposure. Mice that were exposed to E-cig vapor contained serum cotinine concentrations that are comparable to human E-cig users. E-cig exposure for 2 weeks produced a significant increase in oxidative stress and moderate macrophage-mediated inflammation. Since, COPD patients are susceptible to bacterial and viral infections, we tested effects of E-cigs on immune response. Mice that were exposed to E-cig vapor showed significantly impaired pulmonary bacterial clearance, compared to air-exposed mice, following an intranasal infection with Streptococcus pneumonia. This defective bacterial clearance was partially due to reduced phagocytosis by alveolar macrophages from E-cig exposed mice. In response to Influenza A virus infection, E-cig exposed mice displayed increased lung viral titers and enhanced virus-induced illness and mortality. In summary, this study reports a murine model of E-cig exposure and demonstrates that E-cig exposure elicits impaired pulmonary anti-microbial defenses. Hence, E-cig exposure as an alternative to cigarette smoking must be rigorously tested in users for their effects on immune response and susceptibility to bacterial and viral infections. PMID:25651083

  12. Ticks and tick-borne pathogens at the cutaneous interface: host defenses, tick countermeasures, and a suitable environment for pathogen establishment

    OpenAIRE

    Stephen eWikel

    2013-01-01

    Ticks are unique among hematophagous arthropods by continuous attachment to host skin and blood feeding for days; complexity and diversity of biologically active molecules differentially expressed in saliva of tick species; their ability to modulate the host defenses of pain and itch, hemostasis, inflammation, innate and adaptive immunity, and wound healing; and, the diverse array of infectious agents they transmit. All of these interactions occur at the cutaneous interface in a complex seque...

  13. IRAK-M regulation and function in host defense and immune homeostasis

    Directory of Open Access Journals (Sweden)

    Leah L.N. Hubbard

    2010-06-01

    Full Text Available Antigen presenting cells (APCs of the innate immune system sense a wide range of pathogens via pattern recognition receptors (PRRs. Engagement of certain PRRs can induce production of pro-inflammatory mediators that facilitate effective clearance of pathogen. Toll-like receptors (TLRs are a well described group of PRRs that belong to the TLR/Interleukin-1 receptor (IL-1R superfamily. However, TLR/IL-1R induction of pro-inflammatory mediators must be regulated to prevent excessive inflammation and tissue damage. One molecule of recent interest that is known to inhibit TLR/IL-1R signaling is interleukin-1 receptor associated kinase (IRAK-M, also known as IRAK-3. IRAK-M is expressed in a number of immune and epithelial cells types, and through its inhibition of pro-inflammatory cytokine production, IRAK-M can regulate immune homeostasis and tolerance in a number of infectious and non-infectious diseases. Furthermore, use of IRAK-M deficient animals has increased our understanding of the importance of IRAK-M in regulating immune responsiveness to a variety of pathogens. Although IRAK-M expression is typically induced through TLR signaling, IRAK-M can also be expressed in response to various endogenous and exogenous soluble factors as well as cell surface and intracellular signaling molecules. This review will focus on clinical scenarios in which expression of IRAK-M is beneficial (as in early sepsis and those situations where IRAK-M expression is harmful to the host (as in cancer and following bone marrow transplant. There is strong rationale for therapeutic targeting of IRAK-M for clinical benefit. However, effective targeting will require a greater understanding of the transcriptional regulation of this gene.

  14. A Comparative Study of Lung Host Defense in Murine Obesity Models. Insights into Neutrophil Function.

    Science.gov (United States)

    Ubags, Niki D J; Burg, Elianne; Antkowiak, Maryellen; Wallace, Aaron M; Dilli, Estee; Bement, Jenna; Wargo, Matthew J; Poynter, Matthew E; Wouters, Emiel F M; Suratt, Benjamin T

    2016-08-01

    We have shown that obesity-associated attenuation of murine acute lung injury is driven, in part, by blunted neutrophil chemotaxis, yet differences were noted between the two models of obesity studied. We hypothesized that obesity-associated impairment of multiple neutrophil functions contributes to increased risk for respiratory infection but that such impairments may vary between murine models of obesity. We examined the most commonly used murine obesity models (diet-induced obesity, db/db, CPE(fat/fat), and ob/ob) using a Klebsiella pneumoniae pneumonia model and LPS-induced pneumonitis. Marrow-derived neutrophils from uninjured lean and obese mice were examined for in vitro functional responses. All obesity models showed impaired clearance of K. pneumoniae, but in differing temporal patterns. Failure to contain infection in obese mice was seen in the db/db model at both 24 and 48 hours, yet this defect was only evident at 24 hours in CPE(fat/fat) and ob/ob models, and at 48 hours in diet-induced obesity. LPS-induced airspace neutrophilia was decreased in all models, and associated with blood neutropenia in the ob/ob model but with leukocytosis in the others. Obese mouse neutrophils from all models demonstrated impaired chemotaxis, whereas neutrophil granulocyte colony-stimulating factor-mediated survival, LPS-induced cytokine transcription, and mitogen-activated protein kinase and signal transducer and activator of transcription 3 activation in response to LPS and granulocyte colony-stimulating factor, respectively, were variably impaired across the four models. Obesity-associated impairment of host response to lung infection is characterized by defects in neutrophil recruitment and survival. However, critical differences exist between commonly used mouse models of obesity and may reflect variable penetrance of elements of the metabolic syndrome, as well as other factors. PMID:27128821

  15. Neutrophil-mediated oxidative burst and host defense are controlled by a Vav-PLCgamma2 signaling axis in mice.

    Science.gov (United States)

    Graham, Daniel B; Robertson, Charles M; Bautista, Jhoanne; Mascarenhas, Francesca; Diacovo, M Julia; Montgrain, Vivianne; Lam, Siu Kit; Cremasco, Viviana; Dunne, W Michael; Faccio, Roberta; Coopersmith, Craig M; Swat, Wojciech

    2007-11-01

    Oxidative burst, a critical antimicrobial mechanism of neutrophils, involves the rapid generation and release of reactive oxygen intermediates (ROIs) by the NADPH oxidase complex. Genetic mutations in an NADPH oxidase subunit, gp91 (also referred to as NOX2), are associated with chronic granulomatous disease (CGD), which is characterized by recurrent and life-threatening microbial infections. To combat such infections, ROIs are produced by neutrophils after stimulation by integrin-dependent adhesion to the ECM in conjunction with stimulation from inflammatory mediators, or microbial components containing pathogen-associated molecular patterns. In this report, we provide genetic evidence that both the Vav family of Rho GTPase guanine nucleotide exchange factors (GEFs) and phospholipase C-gamma2 (PLC-gamma2) are critical mediators of adhesion-dependent ROI production by neutrophils in mice. We also demonstrated that Vav was critically required for neutrophil-dependent host defense against systemic infection by Staphylococcus aureus and Pseudomonas aeruginosa, 2 common pathogens associated with fatal cases of hospital-acquired pneumonia. We identified a molecular pathway in which Vav GEFs linked integrin-mediated signaling with PLC-gamma2 activation, release of intracellular Ca2+ cations, and generation of diacylglycerol to control assembly of the NADPH oxidase complex and ROI production by neutrophils. Taken together, our data indicate that integrin-dependent signals generated during neutrophil adhesion contribute to the activation of NADPH oxidase by a variety of distinct effector pathways, all of which require Vav. PMID:17932569

  16. Neutrophil-mediated oxidative burst and host defense are controlled by a Vav-PLCγ2 signaling axis in mice

    Science.gov (United States)

    Graham, Daniel B.; Robertson, Charles M.; Bautista, Jhoanne; Mascarenhas, Francesca; Diacovo, M. Julia; Montgrain, Vivianne; Lam, Siu Kit; Cremasco, Viviana; Dunne, W. Michael; Faccio, Roberta; Coopersmith, Craig M.; Swat, Wojciech

    2007-01-01

    Oxidative burst, a critical antimicrobial mechanism of neutrophils, involves the rapid generation and release of reactive oxygen intermediates (ROIs) by the NADPH oxidase complex. Genetic mutations in an NADPH oxidase subunit, gp91 (also referred to as NOX2), are associated with chronic granulomatous disease (CGD), which is characterized by recurrent and life-threatening microbial infections. To combat such infections, ROIs are produced by neutrophils after stimulation by integrin-dependent adhesion to the ECM in conjunction with stimulation from inflammatory mediators, or microbial components containing pathogen-associated molecular patterns. In this report, we provide genetic evidence that both the Vav family of Rho GTPase guanine nucleotide exchange factors (GEFs) and phospholipase C–γ2 (PLC-γ2) are critical mediators of adhesion-dependent ROI production by neutrophils in mice. We also demonstrated that Vav was critically required for neutrophil-dependent host defense against systemic infection by Staphylococcus aureus and Pseudomonas aeruginosa, 2 common pathogens associated with fatal cases of hospital-acquired pneumonia. We identified a molecular pathway in which Vav GEFs linked integrin-mediated signaling with PLC-γ2 activation, release of intracellular Ca2+ cations, and generation of diacylglycerol to control assembly of the NADPH oxidase complex and ROI production by neutrophils. Taken together, our data indicate that integrin-dependent signals generated during neutrophil adhesion contribute to the activation of NADPH oxidase by a variety of distinct effector pathways, all of which require Vav. PMID:17932569

  17. A novel form of bacterial resistance to the action of eukaryotic host defense peptides, the use of a lipid receptor.

    Science.gov (United States)

    Dennison, Sarah R; Harris, Frederick; Mura, Manuela; Morton, Leslie H G; Zvelindovsky, Andrei; Phoenix, David A

    2013-09-01

    Host defense peptides show great potential for development as new antimicrobial agents with novel mechanisms of action. However, a small number of resistance mechanisms to their action are known, and here, we report a novel bacterial resistance mechanism mediated by a lipid receptor. Maximin H5 from Bombina maxima bound anionic and zwitterionic membranes with low affinity (Kd > 225 μM) while showing a strong ability to lyse (>55%) and penetrate (π > 6.0 mN m(-1)) these membranes. However, the peptide bound Escherichia coli and 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine (DMPE) membranes with higher affinity (Kd 1.0 mN m(-1)). Increasing levels of membrane DMPE correlated with enhanced binding by the peptide (R(2) = 0.96) but inversely correlated with its lytic ability (R(2) = 0.98). Taken with molecular dynamic simulations, these results suggest that maximin H5 possesses membranolytic activity, primarily involving bilayer insertion of its strongly hydrophobic N-terminal region. However, this region was predicted to form multiple hydrogen bonds with phosphate and ammonium groups within PE head-groups, which in concert with charge-charge interactions anchor the peptide to the surface of E. coli membranes, inhibiting its membranolytic action. PMID:23895279

  18. The acute and sub-chronic exposures of goldfish to naphthenic acids induce different host defense responses.

    Science.gov (United States)

    Hagen, Mariel O; Garcia-Garcia, Erick; Oladiran, Ayoola; Karpman, Matthew; Mitchell, Scott; El-Din, Mohamed Gamal; Martin, Jonathan W; Belosevic, Miodrag

    2012-03-01

    Naphthenic acids (NAs) are believed to be the major toxic component in oil sands process-affected water (OSPW) produced by the oil sands mining industry in Northern Alberta, Canada. We recently reported that oral exposure to NAs alters mammalian immune responses, but the effect of OSPW or NAs on the immune mechanisms of aquatic organisms has not been fully elucidated. We analyzed the effects of acute and sub-chronic NAs exposures on goldfish immune responses by measuring the expression of three pro-inflammatory cytokine genes, antimicrobial functions of macrophages, and host defense after challenge with a protozoan pathogen (Trypanosoma carassii). One week after NAs exposure, fish exhibited increased expression of pro-inflammatory cytokines (IFNγ, IL-1β1, TNF-α2) in the gills, kidney and spleen. Primary macrophages from fish exposed to NAs for one week, exhibited increased production of nitric oxide and reactive oxygen intermediates. Goldfish exposed for one week to 20 mg/L NAs were more resistant to infection by T. carassii. In contrast, sub-chronic exposure of goldfish (12 weeks) to NAs resulted in decreased expression of pro-inflammatory cytokines in the gills, kidney and spleen. The sub-chronic exposure to NAs reduced the ability of goldfish to control the T. carassii infection, exemplified by a drastic increase in fish mortality and increased blood parasite loads. This is the first report analyzing the effects of OSPW contaminants on the immune system of aquatic vertebrates. We believe that the bioassays depicted in this work will be valuable tools for analyzing the efficacy of OSPW remediation techniques and assessment of diverse environmental pollutants. PMID:22227375

  19. Induction of porcine host defense peptide gene expression by short-chain fatty acids and their analogs.

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    Xiangfang Zeng

    Full Text Available Dietary modulation of the synthesis of endogenous host defense peptides (HDPs represents a novel antimicrobial approach for disease control and prevention, particularly against antibiotic-resistant infections. However, HDP regulation by dietary compounds such as butyrate is species-dependent. To examine whether butyrate could induce HDP expression in pigs, we evaluated the expressions of a panel of porcine HDPs in IPEC-J2 intestinal epithelial cells, 3D4/31 macrophages, and primary monocytes in response to sodium butyrate treatment by real-time PCR. We revealed that butyrate is a potent inducer of multiple, but not all, HDP genes. Porcine β-defensin 2 (pBD2, pBD3, epididymis protein 2 splicing variant C (pEP2C, and protegrins were induced markedly in response to butyrate, whereas pBD1 expression remained largely unaltered in any cell type. Additionally, a comparison of the HDP-inducing efficacy among saturated free fatty acids of different aliphatic chain lengths revealed that fatty acids containing 3-8 carbons showed an obvious induction of HDP expression in IPEC-J2 cells, with butyrate being the most potent and long-chain fatty acids having only a marginal effect. We further investigated a panel of butyrate analogs for their efficacy in HDP induction, and found glyceryl tributyrate, benzyl butyrate, and 4-phenylbutyrate to be comparable with butyrate. Identification of butyrate and several analogs with a strong capacity to induce HDP gene expression in pigs provides attractive candidates for further evaluation of their potential as novel alternatives to antibiotics in augmenting innate immunity and disease resistance of pigs.

  20. Requirement of Interleukin 17 Receptor Signaling for Lung Cxc Chemokine and Granulocyte Colony-Stimulating Factor Expression, Neutrophil Recruitment, and Host Defense

    OpenAIRE

    Ye, Peng; Rodriguez, Fred H.; Kanaly, Suzanne; Stocking, Kim L.; Schurr, Jill; Schwarzenberger, Paul; Oliver, Peter; Huang, Weitao; Zhang, Ping; Zhang, Jason; Shellito, Judd E.; Bagby, Greg J.; Nelson, Steve; Charrier, Keith; Peschon, Jacques J.

    2001-01-01

    Bacterial pneumonia is an increasing complication of HIV infection and inversely correlates with the CD4+ lymphocyte count. Interleukin (IL)-17 is a cytokine produced principally by CD4+ T cells, which induces granulopoiesis via granulocyte colony-stimulating factor (G-CSF) production and induces CXC chemokines. We hypothesized that IL-17 receptor (IL-17R) signaling is critical for G-CSF and CXC chemokine production and lung host defenses. To test this, we used a model of Klebsiella pneumonia...

  1. Peptidomic analysis of the extensive array of host-defense peptides in skin secretions of the dodecaploid frog Xenopus ruwenzoriensis (Pipidae).

    Science.gov (United States)

    Coquet, Laurent; Kolodziejek, Jolanta; Jouenne, Thierry; Nowotny, Norbert; King, Jay D; Conlon, J Michael

    2016-09-01

    The Uganda clawed frog Xenopus ruwenzoriensis with a karyotype of 2n=108 is one of the very few vertebrates with dodecaploid status. Peptidomic analysis of norepinephrine-stimulated skin secretions from this species led to the isolation and structural characterization of 23 host-defense peptides belonging to the following families: magainin (3 peptides), peptide glycine-leucine-amide (PGLa; 6 peptides), xenopsin precursor fragment (XPF; 3 peptides), caerulein precursor fragment (CPF; 8 peptides), and caerulein precursor fragment-related peptide (CPF-RP; 3 peptides). In addition, the secretions contained caerulein, identical to the peptide from Xenopus laevis, and two peptides that were identified as members of the trefoil factor family (TFF). The data indicate that silencing of the host-defense peptide genes following polyploidization has been appreciable and non-uniform. Consistent with data derived from comparison of nucleotide sequences of mitochrondrial and nuclear genes, cladistic analyses based upon the primary structures of the host-defense peptides provide support for an evolutionary scenario in which X. ruwenzoriensis arose from an allopolyploidization event involving an octoploid ancestor of the present-day frogs belonging to the Xenopus amieti species group and a tetraploid ancestor of Xenopus pygmaeus. PMID:27290612

  2. Survival to parasitoids in an insect hosting defensive symbionts: a multivariate approach to polymorphic traits affecting host use by its natural enemy.

    Directory of Open Access Journals (Sweden)

    Emilie Bilodeau

    Full Text Available Insect parasitoids and their insect hosts represent a wide range of parasitic trophic relations that can be used to understand the evolution of biotic diversity on earth. Testing theories of coevolution between hosts and parasites is based on factors directly involved in host susceptibility and parasitoid virulence. We used controlled encounters with potential hosts of the Aphidius ervi wasp to elucidate behavioral and other phenotypic traits of host Acyrthosiphon pisum that most contribute to success or failure of parasitism. The host aphid is at an advanced stage of specialization on different crop plants, and exhibits intra-population polymorphism for traits of parasitoid avoidance and resistance based on clonal variation of color morph and anti-parasitoid bacterial symbionts. Randomly selected aphid clones from alfalfa and clover were matched in 5 minute encounters with wasps of two parasitoid lineages deriving from hosts of each plant biotype in a replicated transplant experimental design. In addition to crop plant affiliation (alfalfa, clover, aphid clones were characterized for color morph (green, pink, Hamiltonella defensa and Regiella insecticola symbionts, and frequently used behaviors in encounters with A. ervi wasps. A total of 12 explanatory variables were examined using redundancy analysis (RDA to predict host survival or failure to A. ervi parasitism. Aphid color was the best univariate predictor, but was poorly predictive in the RDA model. In contrast, aphid host plant and symbionts were not significant univariate predictors, but significant predictors in the multivariate model. Aphid susceptibility to wasp acceptance as reflected in host attacks and oviposition clearly differed from its suitability to parasitism and progeny development. Parasitoid progeny were three times more likely to survive on clover than alfalfa host aphids, which was compensated by behaviorally adjusting eggs invested per host. Strong variation of the

  3. Dual role of Fcγ receptors in host defense and disease in Borrelia burgdorferi-infected mice

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    Alexia Anne Belperron

    2014-06-01

    Full Text Available Arthritis in mice infected with the Lyme disease spirochete, Borrelia burgdorferi, results from the influx of innate immune cells responding to the pathogen in the joint and is influenced in part by mouse genetics. Production of inflammatory cytokines by innate immune cells in vitro is largely mediated by Toll-like receptor (TLR interaction with Borrelia lipoproteins, yet surprisingly mice deficient in TLR2 or the TLR signaling molecule MyD88 still develop arthritis comparable to that seen in wild type mice after B. burgdorferi infection. These findings suggest that other, MyD88-independent inflammatory pathways can contribute to arthritis expression. Clearance of B. burgdorferi is dependent on the production of specific antibody and phagocytosis of the organism. As Fc receptors (FcγR are important for IgG-mediated clearance of immune complexes and opsonized particles by phagocytes, we examined the role that FcγR play in host defense and disease in B. burgdorferi-infected mice. B. burgdorferi-infected mice deficient in the Fc receptor common gamma chain (FcεRγ-/- mice harbored ~10 fold more spirochetes than similarly infected wild type mice, and this was associated with a transient increase in arthritis severity. While the elevated pathogen burdens seen in B. burgdorferi-infected MyD88-/- mice were not affected by concomitant deficiency in FcγR, arthritis was reduced in FcεRγ-/-MyD88-/- mice in comparison to wild type or single knockout mice. Gene expression analysis from infected joints demonstrated that absence of both MyD88 and FcγR lowers mRNA levels of proteins involved in inflammation, including Cxcl1 (KC, Xcr1 (Gpr5, IL-1beta, and C reactive protein. Taken together, our results demonstrate a role for FcγR-mediated immunity in limiting pathogen burden and arthritis in mice during the acute phase of B. burgdorferi infection, and further suggest that this pathway contributes to the arthritis that develops in B. burgdorferi

  4. NF-κB Inhibition after Cecal Ligation and Puncture Reduces Sepsis-Associated Lung Injury without Altering Bacterial Host Defense

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    Hui Li

    2013-01-01

    Full Text Available Introduction. Since the NF-κB pathway regulates both inflammation and host defense, it is uncertain whether interventions targeting NF-κB would be beneficial in sepsis. Based on the kinetics of the innate immune response, we postulated that selective NF-κB inhibition during a defined time period after the onset of sepsis would reduce acute lung injury without compromising bacterial host defense. Methods. Mice underwent cecal ligation and puncture (CLP. An NF-κB inhibitor, BMS-345541 (50 µg/g mice, was administered by peroral gavage beginning 2 hours after CLP and repeated at 6 hour intervals for 2 additional doses. Results. Mice treated with BMS-345541 after CLP showed reduced neutrophilic alveolitis and lower levels of KC in bronchoalveolar lavage fluid compared to mice treated with CLP+vehicle. In addition, mice treated with CLP+BMS had minimal histological evidence of lung injury and normal wet-dry ratios, indicating protection from acute lung injury. Treatment with the NF-κB inhibitor did not affect the ability of cultured macrophages to phagocytose bacteria and did not alter bacterial colony counts in blood, lung tissue, or peritoneal fluid at 24 hours after CLP. While BMS-345541 treatment did not alter mortality after CLP, our results showed a trend towards improved survival. Conclusion. Transiently blocking NF-κB activity after the onset of CLP-induced sepsis can effectively reduce acute lung injury in mice without compromising bacterial host defense or survival after CLP.

  5. Eosinophil-Derived Neurotoxin (EDN/RNase 2 and the Mouse Eosinophil-Associated RNases (mEars: Expanding Roles in Promoting Host Defense

    Directory of Open Access Journals (Sweden)

    Helene F. Rosenberg

    2015-07-01

    Full Text Available The eosinophil-derived neurotoxin (EDN/RNase2 and its divergent orthologs, the mouse eosinophil-associated RNases (mEars, are prominent secretory proteins of eosinophilic leukocytes and are all members of the larger family of RNase A-type ribonucleases. While EDN has broad antiviral activity, targeting RNA viruses via mechanisms that may require enzymatic activity, more recent studies have elucidated how these RNases may generate host defense via roles in promoting leukocyte activation, maturation, and chemotaxis. This review provides an update on recent discoveries, and highlights the versatility of this family in promoting innate immunity.

  6. Interleukin-17A Enhances Host Defense against Cryptococcal Lung Infection through Effects Mediated by Leukocyte Recruitment, Activation, and Gamma Interferon Production

    OpenAIRE

    Murdock, Benjamin J.; Huffnagle, Gary B.; Olszewski, Michal A.; Osterholzer, John J.

    2014-01-01

    Infection of C57BL/6 mice with the moderately virulent Cryptococcus neoformans strain 52D models the complex adaptive immune response observed in HIV-negative patients with persistent fungal lung infections. In this model, Th1 and Th2 responses evolve over time, yet the contribution of interleukin-17A (IL-17A) to antifungal host defense is unknown. In this study, we show that fungal lung infection promoted an increase in Th17 T cells that persisted to 8 weeks postinfection. Our comparison of ...

  7. Smuggling across the border: how arthropod-borne pathogens evade and exploit the host defense system of the skin.

    Science.gov (United States)

    Bernard, Quentin; Jaulhac, Benoit; Boulanger, Nathalie

    2014-05-01

    The skin is a critical barrier between hosts and pathogens in arthropod-borne diseases. It harbors many resident cells and specific immune cells to arrest or limit infections by secreting inflammatory molecules or by directly killing pathogens. However, some pathogens are able to use specific skin cells and arthropod saliva for their initial development, to hide from the host immune system, and to establish persistent infection in the vertebrate host. A better understanding of the initial mechanisms taking place in the skin should allow the development of new strategies to fight these vector-borne pathogens that are spread worldwide and are of major medical importance. PMID:24552683

  8. Role of Toll-like receptors in lung innate defense against invasive aspergillosis. Distinct impact in immunocompetent and immunocompromized hosts.

    OpenAIRE

    Chignard, Michel; Balloy, Viviane; Sallenave, Jean-Michel; Si-Tahar, Mustapha

    2007-01-01

    Toll-like receptors are key to pathogen recognition by a host and to the subsequent triggering of an innate immune response. Experimental and clinical evidence shows that defects in Toll-like receptors or in signaling pathways downstream from these receptors render hosts susceptible to various types of infection, including aspergillosis. Patients receiving an immunosuppressive regimen, including corticosteroid therapy or cytotoxic chemotherapy, are also susceptible to infections. Aspergillus ...

  9. Characterization of the host-defense peptides from skin secretions of Merlin's clawed frog Pseudhymenochirus merlini: insights into phylogenetic relationships among the Pipidae.

    Science.gov (United States)

    Conlon, J Michael; Prajeep, Manju; Mechkarska, Milena; Coquet, Laurent; Leprince, Jérôme; Jouenne, Thierry; Vaudry, Hubert; King, Jay D

    2013-12-01

    The family Pipidae comprises the genera Hymenochirus, Pipa, Pseudhymenochirus, Silurana, and Xenopus but phylogenetic relationships within the family are unclear. Peptidomic analysis of norepinephrine-stimulated skin secretions from Pseudhymenochirus merlini Chabanaud, 1920, the single species within the genus Pseudhymenochirus, led to identification of 13 host-defense peptides with antimicrobial activity. Two peptides (hymenochirin-1Pa and -1Pb) show structural similarity to hymenochirin-1B from Hymenochirus boettgeri and eight peptides (hymenochirin-5Pa, -5Pb, -5Pc, -5Pd, -5Pe, -5Pf, 5Pg and -5Ph) are structurally similar to each other and to hymenochirin-5B from H. boettgeri. Two peptides differing by a single amino acid (IKIPSFFRNILKKVGKEAVSLM/I AGALKQS), termed pseudhymenochirin-1Pa and -1Pb, and pseudhymenochirin-2Pa (GIFPIFAKLLGKVIKVASSLISKGRTE) do not resemble host-defense peptides previously isolated from pipid frogs. Hymenochirin-5Pe was the most abundant peptide in the secretions and hymenochirin-1Pa the most potent against Staphylococcus aureus (MIC=2.5μM) and Escherichia coli (MIC=10μM). The data support a close phylogenetic relationship between Hymenochirus and Pseudhymenochirus that is distinct from the Xenopodinae (Xenopus+Silurana) clade with Pipa sister-group to all other extant pipids. PMID:24212286

  10. Role of Toll-like receptors in lung innate defense against invasive aspergillosis. Distinct impact in immunocompetent and immunocompromized hosts.

    Science.gov (United States)

    Chignard, Michel; Balloy, Viviane; Sallenave, Jean-Michel; Si-Tahar, Mustapha

    2007-09-01

    Toll-like receptors are key to pathogen recognition by a host and to the subsequent triggering of an innate immune response. Experimental and clinical evidence shows that defects in Toll-like receptors or in signaling pathways downstream from these receptors render hosts susceptible to various types of infection, including aspergillosis. Patients receiving an immunosuppressive regimen, including corticosteroid therapy or cytotoxic chemotherapy, are also susceptible to infections. Aspergillus fumigatus is an opportunistic pathogen that infects the lungs of immunosuppressed hosts. Here, we review the evidence that experimental inactivation of various Toll-like receptors and of their signaling pathways may worsen cases of invasive pulmonary aspergillosis. Moreover, the literature clearly indicates that the type of immunosuppression is very important, as it influences whether or not Toll-like receptors contribute to infection. The involvement of Toll-like receptors, based on the immunological status of the patient, should be considered if an immunosuppressive treatment must be administered. PMID:17604224

  11. Non-antibacterial tetracycline formulations: host-modulators in the treatment of periodontitis and relevant systemic diseases.

    Science.gov (United States)

    Golub, Lorne M; Elburki, Muna S; Walker, Clay; Ryan, Maria; Sorsa, Timo; Tenenbaum, Howard; Goldberg, Michael; Wolff, Mark; Gu, Ying

    2016-06-01

    Traditionally, the dental profession has primarily treated periodontitis using a mechanical/surgical, rather than a pharmaceutical, approach. However, based on experiments several decades ago which demonstrated that tetracyclines, unexpectedly, inhibit collagen- and bone-destructive mammalian-derived enzymes (e.g. the collagenases), and through non-antibiotic mechanisms, the concept of host-modulation therapy (HMT) was developed. Accordingly, two drug-development strategies evolved: (i) the development of non-antimicrobial formulations of doxycycline; and (ii) the chemical modification of tetracyclines to eliminate their antibiotic activity but retain (or even enhance) their anti-collagenase properties. Regarding the latter, these chemically modified tetracyclines (CMTs) showed efficacy in vitro, in animal models of periodontal (and relevant systemic) disease, and in preliminary clinical trials on patients with Kaposi's sarcoma (however, at the high doses used, photosensitivity was a significant side-effect). In the first strategy, subantimicrobial-dose doxycycline (SDD) demonstrated safety and efficacy in human clinical trials and was approved by the U S Food and Drug Administration (U S FDA) and in other countries for the treatment of periodontitis (20 mg, twice daily, i.e. once every 12 hours) adjunctive to scaling and root planing, and for chronic inflammatory skin diseases (40-mg sustained-release 'beads'). SDD also showed efficacy in patients with systemic diseases relevant to periodontitis, including diabetes mellitus and arthritis, and in postmenopausal women with local and systemic bone loss. Importantly, long-term administration of SDD, of up to 2 years, in clinical trials did not produce antibiotic side-effects. SDD (and in the future, new HMTs, such as low-dose CMT-3, resolvins and chemically modified curcumins) may shift the paradigm of periodontal therapy from a predominantly surgical approach to the greater use of medicinal/pharmacologic strategies

  12. DNA vaccination based on pyolysin co-immunized with IL-1β enhances host antibacterial immunity against Trueperella pyogenes infection.

    Science.gov (United States)

    Huang, Ting; Zhao, Kelei; Zhang, Ziqi; Tang, Ce; Zhang, Xiuyue; Yue, Bisong

    2016-06-24

    Trueperella pyogenes is a commensal and opportunistic pathogen normally causes mastitis, liver abscesses and pneumonia of economically important livestock. To date, no specific control measure was reported to prevent T. pyogenes infections. In this study, we first constructed a recombinant plasmid pVAX1-PLO based on the main virulent factor pyolysin gene as DNA vaccine against T. pyogenes infection. Subsequently, transient expression of pVAX1-PLO and pcDNA3.1/V5-fIL-1β were identified in Human embryonic kidney cells (HEK293T) by immunofluorescence assay. Humoral and cellular immune responses were evaluated in mice to compare the immunogenicity between different immunized groups. The results showed that the successful expression of PLO or fIL-1β protein was detected by confocal microscopy for cells transfected with plasmid pVAX1-PLO and/or pcDNA3.1/V5-fIL-1β. The mice immunized with pVAX1-PLO elicited a higher titer of PLO-specific antibody than the control group. The levels of IFN-γ and IL-2 were significantly increased in the pVAX1-PLO immunized mice, while the expression level of IL-4 was slightly increased but not significant. These findings suggested that the DNA vaccine pVAX1-PLO can primarily induce Th1 immune response. The residual Colony-Forming Units (CFUs) from the liver and peritoneal fluid were decreased obviously in the pVAX1-PLO treated mice compared with the control. Importantly, co-immunization with pcDNA3.1/V5-fIL-1β and pVAX1-PLO could enhance host humoral and cellular immune responses and significantly protect mouse from T. pyogenes infection. In conclusion, our study provides a promising strategy against T. pyogenes infections and implies the potential clinical application of combined DNA vaccines in diseases control. PMID:27091688

  13. A Virulence Essential CRN Effector of Phytophthora capsici Suppresses Host Defense and Induces Cell Death in Plant Nucleus

    OpenAIRE

    Mafurah, Joseph Juma; Ma, Huifei; Zhang, Meixiang; Xu, Jing; HE Feng; Ye, Tingyue; Shen, Danyu; Yanyu CHEN; Rajput, Nasir Ahmed; Dou, Daolong

    2015-01-01

    Phytophthora capsici is a soil-borne plant pathogen with a wide range of hosts. The pathogen secretes a large array of effectors during infection of host plants, including Crinkler (CRN) effectors. However, it remains largely unknown on the roles of these effectors in virulence especially in P. capsici. In this study, we identified a cell death-inducing CRN effector PcCRN4 using agroinfiltration approach. Transient expression of PcCRN4 gene induced cell death in N. benthamiana, N. tabacum and...

  14. Herbal Antibacterials: A Review

    OpenAIRE

    Chirag Modi; Shailesh Mody; Hitesh Patel; Ghanshyam Dudhatra; Avinash Kumar; Madhavi Awale

    2012-01-01

    Plants are rich source of antibacterial agents because they produce wide array of bioactive molecules, most of which probably evolved as chemical defense against predation or infection. A major part of the total population in developing countries still uses traditional folk medicine obtained from plant resources With an estimation of WHO that as many as 80% of world population living in rural areas rely on herbal traditional medicines as their primary health care, the study on properties and...

  15. Transcriptome Analysis Reveals Novel Entry Mechanisms and a Central Role of SRC in Host Defense during High Multiplicity Mycobacterial Infection.

    Directory of Open Access Journals (Sweden)

    Jay Zhang

    Full Text Available Mycobacterium tuberculosis (MTB infects an estimated one-third of the global population and is one of the main causes of mortality from an infectious agent. The characteristics of macrophages challenged by MTB with a high multiplicity of infection (MOI, which mimics both clinical disseminated infection and granuloma formation, are distinct from macrophages challenged with a low MOI. To better understand the cross talk between macrophage host cells and mycobacteria, we compared the transcription patterns of mouse macrophages infected with bacille Calmette-Guérin, H37Ra and M. smegmatis. Attention was focused on the changes in the abundance of transcripts related to immune system function. From the results of a transcriptome profiling study with a high mycobacterial MOI, we defined a pathogen-specific host gene expression pattern. The present study suggests that two integrins, ITGA5 and ITGAV, are novel cell surface receptors mediating mycobacterium entry into macrophages challenged with high MOI. Our results indicate that SRC likely plays a central role in regulating multiple unique signaling pathways activated by MTB infection. The integrated results increase our understanding of the molecular networks behind the host innate immune response and identify important targets that might be useful for the development of tuberculosis therapy.

  16. Cement-based radioactive waste hosts formed under elevated temperatures and pressures (FUETAP concretes) for Savannah River Plant high-level defense waste

    International Nuclear Information System (INIS)

    Concretes that are formed under elevated temperatures and pressures (called FUETAP) are effective hosts for high-level radioactive defense wastes. Tailored concretes developed at the Oak Ridge National Laboratory (ORNL) have been prepared from common Portland cements, fly ash, sand, clays, and waste products. These concretes are produced by accelerated curing under mild autoclave conditions (85 to 2000C, 0.1 to 1.5 MPa) for 24 h. The solids are subsequently dewatered (to remove unbound water) at 2500C for 24 h. The resulting products are strong (compressive strength, 40 to 100 MPa), leach resistant [plutonium leaches at the rate of 10 pg/(cm2.d)], and radiolytically stable, monolithic waste forms (total gas value = 0.005 molecule/100 eV). This report summarizes the results of a 4-year FUETAP development program for Savannah River Plant (SRP) high-level defense wastes. It addresses the major questions concerning the performance of concretes as radioactive waste forms. These include leachability, radiation stability, thermal stability, thermal conductivity, impact strength, permeability, phase complexity, and effect of waste composition

  17. Pseudomonas fluorescens induces strain-dependent and strain-independent host plant responses in defense networks, primary metabolism, photosynthesis, and fitness.

    Science.gov (United States)

    Weston, David J; Pelletier, Dale A; Morrell-Falvey, Jennifer L; Tschaplinski, Timothy J; Jawdy, Sara S; Lu, Tse-Yuan; Allen, Sara M; Melton, Sarah J; Martin, Madhavi Z; Schadt, Christopher W; Karve, Abhijit A; Chen, Jin-Gui; Yang, Xiaohan; Doktycz, Mitchel J; Tuskan, Gerald A

    2012-06-01

    Colonization of plants by nonpathogenic Pseudomonas fluorescens strains can confer enhanced defense capacity against a broad spectrum of pathogens. Few studies, however, have linked defense pathway regulation to primary metabolism and physiology. In this study, physiological data, metabolites, and transcript profiles are integrated to elucidate how molecular networks initiated at the root-microbe interface influence shoot metabolism and whole-plant performance. Experiments with Arabidopsis thaliana were performed using the newly identified P. fluorescens GM30 or P. fluorescens Pf-5 strains. Co-expression networks indicated that Pf-5 and GM30 induced a subnetwork specific to roots enriched for genes participating in RNA regulation, protein degradation, and hormonal metabolism. In contrast, only GM30 induced a subnetwork enriched for calcium signaling, sugar and nutrient signaling, and auxin metabolism, suggesting strain dependence in network architecture. In addition, one subnetwork present in shoots was enriched for genes in secondary metabolism, photosynthetic light reactions, and hormone metabolism. Metabolite analysis indicated that this network initiated changes in carbohydrate and amino acid metabolism. Consistent with this, we observed strain-specific responses in tryptophan and phenylalanine abundance. Both strains reduced host plant carbon gain and fitness, yet provided a clear fitness benefit when plants were challenged with the pathogen P. syringae DC3000. PMID:22375709

  18. Fire blight disease reactome: RNA-seq transcriptional profile of apple host plant defense responses to Erwinia amylovora pathogen infection.

    Science.gov (United States)

    Kamber, Tim; Buchmann, Jan P; Pothier, Joël F; Smits, Theo H M; Wicker, Thomas; Duffy, Brion

    2016-01-01

    The molecular basis of resistance and susceptibility of host plants to fire blight, a major disease threat to pome fruit production globally, is largely unknown. RNA-sequencing data from challenged and mock-inoculated flowers were analyzed to assess the susceptible response of apple to the fire blight pathogen Erwinia amylovora. In presence of the pathogen 1,080 transcripts were differentially expressed at 48 h post inoculation. These included putative disease resistance, stress, pathogen related, general metabolic, and phytohormone related genes. Reads, mapped to regions on the apple genome where no genes were assigned, were used to identify potential novel genes and open reading frames. To identify transcripts specifically expressed in response to E. amylovora, RT-PCRs were conducted and compared to the expression patterns of the fire blight biocontrol agent Pantoea vagans strain C9-1, another apple pathogen Pseudomonas syringae pv. papulans, and mock inoculated apple flowers. This led to the identification of a peroxidase superfamily gene that was lower expressed in response to E. amylovora suggesting a potential role in the susceptibility response. Overall, this study provides the first transcriptional profile by RNA-seq of the host plant during fire blight disease and insights into the response of susceptible apple plants to E. amylovora. PMID:26883568

  19. S100A8/A9 is not involved in host defense against murine urinary tract infection.

    Directory of Open Access Journals (Sweden)

    Mark C Dessing

    Full Text Available BACKGROUND: Inflammation is commonly followed by the release of endogenous proteins called danger associated molecular patterns (DAMPs that are able to warn the host for eminent danger. S100A8/A9 subunits are DAMPs that belong to the S100 family of calcium binding proteins. S100A8/A9 complexes induce an inflammatory response and their expression correlates with disease severity in several inflammatory disorders. S100A8/A9 promote endotoxin- and Escherichia (E. coli-induced sepsis showing its contribution in systemic infection. The role of S100A8/A9 during a local infection of the urinary tract system caused by E. coli remains unknown. METHODOLOGY/PRINCIPAL FINDINGS: We investigated the contribution of S100A8/A9 in acute urinary tract infection (UTI by instilling 2 different doses of uropathogenic E. coli transurethrally in wild type (WT and S100A9 knockout (KO mice. Subsequently, we determined bacterial outgrowth, neutrophilic infiltrate and inflammatory mediators in bladder and kidney 24 and 48 hours later. UTI resulted in a substantial increase of S100A8/A9 protein in bladder and kidney tissue of WT mice. S100A9 KO mice displayed similar bacterial load in bladder or kidney homogenate compared to WT mice using 2 different doses at 2 different time points. S100A9 deficiency had little effect on the inflammatory responses to E. Coli-induced UTI infection, as assessed by myeloperoxidase activity in bladder and kidneys, histopathologic analysis, and renal and bladder cytokine concentrations. CONCLUSIONS: We show that despite high S100A8/A9 expression in bladder and kidney tissue upon UTI, S100A8/A9 does not contribute to an effective host response against E. Coli in the urinary tract system.

  20. Direct activation of RIP3/MLKL-dependent necrosis by herpes simplex virus 1 (HSV-1) protein ICP6 triggers host antiviral defense

    Science.gov (United States)

    Wang, Xing; Li, Yun; Liu, Shan; Yu, Xiaoliang; Li, Lin; Shi, Cuilin; He, Wenhui; Li, Jun; Xu, Lei; Hu, Zhilin; Yu, Lu; Yang, Zhongxu; Chen, Qin; Ge, Lin; Zhang, Zili; Zhou, Biqi; Jiang, Xuejun; Chen, She; He, Sudan

    2014-01-01

    The receptor-interacting kinase-3 (RIP3) and its downstream substrate mixed lineage kinase domain-like protein (MLKL) have emerged as the key cellular components in programmed necrotic cell death. Receptors for the cytokines of tumor necrosis factor (TNF) family and Toll-like receptors (TLR) 3 and 4 are able to activate RIP3 through receptor-interacting kinase-1 and Toll/IL-1 receptor domain-containing adapter inducing IFN-β, respectively. This form of cell death has been implicated in the host-defense system. However, the molecular mechanisms that drive the activation of RIP3 by a variety of pathogens, other than the above-mentioned receptors, are largely unknown. Here, we report that human herpes simplex virus 1 (HSV-1) infection triggers RIP3-dependent necrosis. This process requires MLKL but is independent of TNF receptor, TLR3, cylindromatosis, and host RIP homotypic interaction motif-containing protein DNA-dependent activator of IFN regulatory factor. After HSV-1 infection, the viral ribonucleotide reductase large subunit (ICP6) interacts with RIP3. The formation of the ICP6–RIP3 complex requires the RHIM domains of both proteins. An HSV-1 ICP6 deletion mutant failed to cause effective necrosis of HSV-1–infected cells. Furthermore, ectopic expression of ICP6, but not RHIM mutant ICP6, directly activated RIP3/MLKL-mediated necrosis. Mice lacking RIP3 exhibited severely impaired control of HSV-1 replication and pathogenesis. Therefore, this study reveals a previously uncharacterized host antipathogen mechanism. PMID:25316792

  1. Matrix metalloproteinase-9 deficiency impairs host defense mechanisms against Streptococcus pneumoniae in a mouse model of bacterial meningitis.

    Science.gov (United States)

    Böttcher, Tobias; Spreer, Annette; Azeh, Ivo; Nau, Roland; Gerber, Joachim

    2003-03-01

    Matrix metalloproteinase-9 (MMP-9) appears to contribute to blood-brain barrier damage and neuronal injury in bacterial meningitis. To further explore the function of MMP-9 in meningeal inflammation, we injected 10(4) colony forming units (CFU) of a Streptoccocus pneumoniae type 3 strain into the right forebrain of MMP-9 deficient mice (MMP-9(-/-), n=16) and wild-type controls (129 x B6, n=15). The clinical course of the disease, leukocyte recruitment into the subarachnoid space and bacterial titers in the brain did not differ. Yet, clearance of the bacteria from blood (log CFU/ml 4.7 [3.8/5.4] vs. 3.6 [3.0/4.0]; P=0.005) and spleen homogenates (log CFU/ml 5.3 [4.8/5.5] vs. 4.0 [2.8/4.7]; P=0.01) was reduced in MMP-9 deficient mice. A reduced systemic bacterial clearance of MMP-9(-/-) mice was confirmed in experimental S. pneumoniae peritonitis/sepsis. This implies a compromised systemic, but not intracerebral host response against S. pneumoniae in MMP-9 deficiency. PMID:12581831

  2. A MyD88-dependent IFNγR-CCR2 signaling circuit is required for mobilization of monocytes and host defense against systemic bacterial challenge

    Institute of Scientific and Technical Information of China (English)

    Eric M Pietras; Lloyd S Miller; Carl T Johnson; Ryan M O'Connell; Paul W Dempsey; Genhong Cheng

    2011-01-01

    Monocytes are mobilized to sites of infection via interaction between the chemokine MCP-1 and its receptor, CCR2, at which point they differentiate into macrophages that mediate potent antimicrobial effects. In this study, we investigated the mechanisms by which monocytes are mobilized in response to systemic challenge with the intracellular bacterium Francisella tularensis. We found that mice deficient in MyD88, interferon-γ (IFNγ)R or CCR2 all had defects in the expansion of splenic monocyte populations upon F. tularensis challenge, and in control of F. tularensis infection. Interestingly, MyD88-deficient mice were defective in production of IFNγ, and IFNγR deficient mice exhibited defective production of MCP-1, the ligand for CCR2. Transplantation of IFNγR-deficient bone marrow (BM) into wild-type mice further suggested that mobilization of monocytes in response to F. tularensis challenge required IFNγR expression on BM-derived cells. These studies define a critical host defense circuit wherein MyD88-dependent IFNγ production signals via IFNγR expressed on BM-derived cells, resulting in MCP-1 production and activation of CCR2-dependent mobilization of monocytes in the innate immune response to systemic F. tularensis challenge.

  3. Leaf-mining by Phyllonorycter blancardella reprograms the host-leaf transcriptome to modulate phytohormones associated with nutrient mobilization and plant defense.

    Science.gov (United States)

    Zhang, Hui; Dugé de Bernonville, Thomas; Body, Mélanie; Glevarec, Gaëlle; Reichelt, Michael; Unsicker, Sybille; Bruneau, Maryline; Renou, Jean-Pierre; Huguet, Elisabeth; Dubreuil, Géraldine; Giron, David

    2016-01-01

    Phytohormones have long been hypothesized to play a key role in the interactions between plant-manipulating organisms and their host-plants such as insect-plant interactions that lead to gall or 'green-islands' induction. However, mechanistic understanding of how phytohormones operate in these plant reconfigurations is lacking due to limited information on the molecular and biochemical phytohormonal modulation following attack by plant-manipulating insects. In an attempt to fill this gap, the present study provides an extensive characterization of how the leaf-miner Phyllonorycter blancardella modulates the major phytohormones and the transcriptional activity of plant cells in leaves of Malus domestica. We show here, that cytokinins strongly accumulate in mined tissues despite a weak expression of plant cytokinin-related genes. Leaf-mining is also associated with enhanced biosynthesis of jasmonic acid precursors but not the active form, a weak alteration of the salicylic acid pathway and a clear inhibition of the abscisic acid pathway. Our study consolidates previous results suggesting that insects may produce and deliver cytokinins to the plant as a strategy to manipulate the physiology of the leaf to create a favorable nutritional environment. We also demonstrate that leaf-mining by P. blancardella leads to a strong reprogramming of the plant phytohormonal balance associated with increased nutrient mobilization, inhibition of leaf senescence and mitigation of plant direct and indirect defense. PMID:26068004

  4. Host-defense peptides from skin secretions of Fraser's clawed frog Xenopus fraseri (Pipidae): Further insight into the evolutionary history of the Xenopodinae.

    Science.gov (United States)

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

    2014-12-01

    Peptidomic analysis of norepinephrine-stimulated skin secretions of the tetraploid frog Xenopus fraseri Boulenger, 1905 (Pipidae) led to identification of 13 host-defense peptides. The primary structures of the peptides demonstrate that they belong to the magainin (3 peptides), peptide glycine-leucine-amide, PGLa (4 peptides), and xenopsin-precursor fragment, XPF (2 peptides) families, first identified in Xenopus laevis, together with caerulein precursor fragment-related peptides, CPF-RP (4 peptides), first identified in Silurana tropicalis. In addition, the secretions contain a molecular variant of xenopsin displaying the substitution Arg(4)→Lys compared with X. laevis xenopsin and peptide glycine-tyrosine-amide (PGYa) (GRIIPIYPEFERVFA KKVYPLY.NH2) whose function is unknown. The most potent antimicrobial peptide identified is CPF-RP-F1 (GFGSVLGKALKFGANLL.NH2) with MIC=12.5μM against Staphylococcus aureus and 50μM against Escherichia coli. On the basis of similarities in morphology and advertisement calls, X. fraseri has been placed in a species group that includes the octoploids Xenopus amieti and Xenopus andrei, and the tetraploid Xenopus pygmaeus. Cladistic analyses based upon the primary structures of magainin, PGLa, and CPF-RP peptides support a close evolutionary relationship between X. fraseri, X. amieti and X. andrei but suggest a more distant relationship with X. pygmaeus. PMID:25463057

  5. Herbal Antibacterials: A Review

    Directory of Open Access Journals (Sweden)

    Chirag Modi

    2012-02-01

    Full Text Available Plants are rich source of antibacterial agents because they produce wide array of bioactive molecules, most of which probably evolved as chemical defense against predation or infection. A major part of the total population in developing countries still uses traditional folk medicine obtained from plant resources With an estimation of WHO that as many as 80% of world population living in rural areas rely on herbal traditional medicines as their primary health care, the study on properties and uses of medicinal plants are getting growing interests. In recent years this interest to evaluate plants possessing antibacterial activity for various diseases is growing. Different solvent extracts (aqueous, alcohol and ethanol of leaves, flower and seed of various plants selected based on an ethnobotanical survey from India were subjected to in vitro antibacterial activity assay against Gram-positive and Gram-negative bacteria employing different diffusion method. Based on local use of common diseases and Ethnobotanical knowledge, an attempt has been made to assess the antibacterial properties of selected medicinal plants viz. Argemone mexicana (Shialkanta, Aster lanceolatus (White panicle, Capparis thonningii and Capparis tomentosa (Woolly caper bush, Cardiospermum halicacabum (Balloonvine, Cassia alata (Herpetic alata, Centaurea sclerolepis, Cinnamomum zeylanicum (Cinnamon, Curcuma longa (Turmeric, Cymbopogon nervatus, Ficus religiosa (Peepal, Indigofera aspalathoides (Ajara, Marrubium vulgare (Horehound, Medicago Spp.(Medick, Burclover, Morus alba (Mulberry, Ocimum sanctum (Tulsi, Origanum marjorana (Marjoram, Oxalis corniculata (Amli, Piper nigrum (Kala mirch, Plectranthus amboinicus (Indian borage, Patharchur, Plumeria acutifolia (Kachuchi, Salvadora persica (Piludi, Salvia repens and Syzygium aromaticum (Clove for potential antibacterial activity against some important bacterial strains, namely Bacillus subtilis, Bacillus cereus, Staphylococcus

  6. Protein and lipid interactions of mammalian antibacterial peptides

    OpenAIRE

    Wang, Yuqin

    2001-01-01

    Gene-encoded antibacterial peptides are multifunctional effector molecules and play an important role in host innate immunity. Upon stimulation, the mature active peptides are released from inactive precursors. Cathelicidins constitute a family of antibacterial peptides, which share a conserved N-terminal cathelin-like region followed by a variable C-terminal antibacterial domain. In addition to its antibacterial activity, LL-37, the only cathelicidin found in human, is ...

  7. Synergistic interaction among begomoviruses leads to the suppression of host defense-related gene expression and breakdown of resistance in chilli.

    Science.gov (United States)

    Singh, Ashish Kumar; Kushwaha, Nirbhay; Chakraborty, Supriya

    2016-05-01

    Chilli (Capsicum sp.) is one of the economically important spice and vegetable crops grown in India and suffers great losses due to the infection of begomoviruses. Conventional breeding approaches have resulted in development of a few cultivars of chilli resistant to begomoviruses. A severe leaf curl disease was observed on one such resistant chilli cultivar (Capsicum annuum cv. Kalyanpur Chanchal) grown in the experimental field of the Jawaharlal Nehru University, New Delhi. Four different viral genomic components namely, Chilli leaf curl virus (DNA A), Tomato leaf curl Bangladesh betasatellite (DNA β), Tomato leaf curl New Delhi virus (DNA A), and Tomato leaf curl Gujarat virus (DNA B) were associated with the severe leaf curl disease. Further, frequent association of these four genomic components was also observed in symptomatic plants of other chilli cultivars (Capsicum annuum cv. Kashi Anmol and Capsicum chinense cv. Bhut Jolokia) grown in the experimental field. Interaction studies among the isolated viral components revealed that Nicotiana benthamiana and chilli plants inoculated with four genomic components of begomoviruses exhibited severe leaf curl disease symptoms. In addition, this synergistic interaction resulted in increased viral DNA accumulation in infected plants. Resistant chilli plants co-inoculated with four genomic components of begomoviruses showed drastic reduction of host basal (ascorbate peroxidase, thionin, polyphenol oxidase) and specific defense-related gene (NBS-LRR) expression. Our results suggested that synergistic interaction among begomoviruses created permissive cellular environment in the resistant chilli plants which leads to breakdown of natural resistance, a phenomenon observed for the first time in chilli. PMID:26780359

  8. Disease interactions in a shared host plant: effects of pre-existing viral infection on cucurbit plant defense responses and resistance to bacterial wilt disease.

    Directory of Open Access Journals (Sweden)

    Lori R Shapiro

    Full Text Available Both biotic and abiotic stressors can elicit broad-spectrum plant resistance against subsequent pathogen challenges. However, we currently have little understanding of how such effects influence broader aspects of disease ecology and epidemiology in natural environments where plants interact with multiple antagonists simultaneously. In previous work, we have shown that healthy wild gourd plants (Cucurbita pepo ssp. texana contract a fatal bacterial wilt infection (caused by Erwinia tracheiphila at significantly higher rates than plants infected with Zucchini yellow mosaic virus (ZYMV. We recently reported evidence that this pattern is explained, at least in part, by reduced visitation of ZYMV-infected plants by the cucumber beetle vectors of E. tracheiphila. Here we examine whether ZYMV-infection may also directly elicit plant resistance to subsequent E. tracheiphila infection. In laboratory studies, we assayed the induction of key phytohormones (SA and JA in single and mixed infections of these pathogens, as well as in response to the feeding of A. vittatum cucumber beetles on healthy and infected plants. We also tracked the incidence and progression of wilt disease symptoms in plants with prior ZYMV infections. Our results indicate that ZYMV-infection slightly delays the progression of wilt symptoms, but does not significantly reduce E. tracheiphila infection success. This observation supports the hypothesis that reduced rates of wilt disease in ZYMV-infected plants reflect reduced visitation by beetle vectors. We also documented consistently strong SA responses to ZYMV infection, but limited responses to E. tracheiphila in the absence of ZYMV, suggesting that the latter pathogen may effectively evade or suppress plant defenses, although we observed no evidence of antagonistic cross-talk between SA and JA signaling pathways. We did, however, document effects of E. tracheiphila on induced responses to herbivory that may influence host

  9. IL-17A and Th17 Cells in Lung Inflammation: An Update on the Role of Th17 Cell Differentiation and IL-17R Signaling in Host Defense against Infection

    OpenAIRE

    Reen Wu; Li-Yin Hung; Hsing-Chuan Tsai; Sharlene Velichko

    2013-01-01

    The significance of Th17 cells and interleukin- (IL-)17A signaling in host defense and disease development has been demonstrated in various infection and autoimmune models. Numerous studies have indicated that Th17 cells and its signature cytokine IL-17A are critical to the airway's immune response against various bacteria and fungal infection. Cytokines such as IL-23, which are involved in Th17 differentiation, play a critical role in controlling Klebsiella pneumonia (K. pneumonia) infection...

  10. The Effect of Water Limitation on Volatile Emission, Tree Defense Response, and Brood Success of Dendroctonus ponderosae in Two Pine Hosts, Lodgepole, and Jack Pine

    OpenAIRE

    Lusebrink, Inka; Erbilgin, Nadir; Evenden, Maya L.

    2016-01-01

    The mountain pine beetle (MPB; Dendroctonus ponderosae) has recently expanded its range from lodgepole pine forest into the lodgepole × jack pine hybrid zone in central Alberta, within which it has attacked pure jack pine. This study tested the effects of water limitation on tree defense response of mature lodgepole and jack pine (Pinus contorta and Pinus banksiana) trees in the field. Tree defense response was initiated by inoculation of trees with the MPB-associated fungus Grosmannia clavig...

  11. Molecular cloning, recombinant expression and antibacterial activity analysis of hepcidin from Simensis crocodile (Crocodylus siamensis).

    Science.gov (United States)

    Hao, Juan; Li, Yan-Wei; Xie, Ming-Quan; Li, An-Xing

    2012-01-01

    Hepcidin, a cysteine-rich cationic antibacterial peptide, plays an important role in human defense against pathogen infection. However, its role in reptile immune response and whether it is involved in antibacterial immune have not yet been proven. In order to study the antibacterial activity of Crocodylus siamensis hepcidin (Cshepc), a common reptile which lives in topic region of Southeast Asia, a cDNA sequence of Cshepc was cloned, which included an open reading frame (ORF) of 300 bp encoding a 99 amino acid preprohepcidin. Cshepc has eight cysteines formed four conserved disulfide bridges, similarly to that of human's. Sequence analysis showed that Cshepc mature peptide was more conserved than that of preprohepcidin. Tissue expression analysis indicated that Cshepc transcripts were highly expressed in the liver, muscle and heart of C. siamensis. Recombinant expressed hepcidin could significantly inhibit the growth of the Gram-negative bacteria Escherichia coli and Aeromonas sobria as well as the Gram-positive bacterium Staphylococcus aureus, and Bacillus subtilis in vitro, suggesting that Cshepc, like human hepcidin could play a role in the antibacterial function in hosts innate immune response. PMID:22967859

  12. Immune defense in leaf-cutting ants: a cross-fostering approach.

    Science.gov (United States)

    Armitage, Sophie A O; Broch, Jens F; Marín, Hermogenes Fernández; Nash, David R; Boomsma, Jacobus J

    2011-06-01

    To ameliorate the impact of disease, social insects combine individual innate immune defenses with collective social defenses. This implies that there are different levels of selection acting on investment in immunity, each with their own trade-offs. We present the results of a cross-fostering experiment designed to address the influences of genotype and social rearing environment upon individual and social immune defenses. We used a multiply mating leaf-cutting ant, enabling us to test for patriline effects within a colony, as well as cross-colony matriline effects. The worker's father influenced both individual innate immunity (constitutive antibacterial activity) and the size of the metapleural gland, which secretes antimicrobial compounds and functions in individual and social defense, indicating multiple mating could have important consequences for both defense types. However, the primarily social defense, a Pseudonocardia bacteria that helps to control pathogens in the ants' fungus garden, showed a significant colony of origin by rearing environment interaction, whereby ants that acquired the bacteria of a foster colony obtained a less abundant cover of bacteria: one explanation for this pattern would be co-adaptation between host colonies and their vertically transmitted mutualist. These results illustrate the complexity of the selection pressures that affect the expression of multilevel immune defenses. PMID:21644963

  13. Antibacterials in Household Products

    Science.gov (United States)

    ... products such as soaps, detergents, health and skincare products and household cleaners. How do antibacterials work? ♦ Antibacterials may be ... contain triclosan or other biocide agents? Antibacterials in household products Are there any risks associated with triclosan-containing ...

  14. Antibacterial substance from mucus of a scleractinian coral,Symphyllia gigantea

    Institute of Scientific and Technical Information of China (English)

    CHEN Guohua; HUANG Liangmin; TAN Yehui; YIN Jianqiang; WANG Hankui; HUANG Hui; ZOU Kun; LI Ruiping

    2007-01-01

    Coral mucus covers the surface of coral and contains antibacterial substances as a first line of defense. Coral mucus not only enables the coral itself to resist disease, but also provides antibacterial agents for people. We collected mucus from a scleractinian coral (Symphyllia gigantea) at Sta. Sanya (China), then extracted the antibacterial substances using 10% glacial acetic acid with the help of antiprotease inhibitors, and tested the antibacterial activity by a terrestrial bacterium (Staphylococcus aurevs) and a marine bacterium (Vibrio anguillarum). The result showed that, there were antibacterial agents in the mucus, and their antibacterial activities were lost by treatment of the sample at 90 °C water for 10 min.

  15. Antibacterial Targets in Fatty Acid Biosynthesis

    OpenAIRE

    Wright, H. Tonie; Reynolds, Kevin A.

    2007-01-01

    The fatty acid biosynthesis pathway is an attractive but still largely unexploited target for development of new anti-bacterial agents. The extended use of the anti-tuberculosis drug isoniazid and the antiseptic triclosan, which are inhibitors of fatty acid biosynthesis, validates this pathway as a target for anti-bacterial development. Differences in subcellular organization of the bacterial and eukaryotic multi-enzyme fatty acid synthase systems offer the prospect of inhibitors with host vs...

  16. Neisseria gonorrhoeae modulates iron-limiting innate immune defenses in macrophages.

    Directory of Open Access Journals (Sweden)

    Susu M Zughaier

    Full Text Available Neisseria gonorrhoeae is a strict human pathogen that causes the sexually transmitted infection termed gonorrhea. The gonococcus can survive extracellularly and intracellularly, but in both environments the bacteria must acquire iron from host proteins for survival. However, upon infection the host uses a defensive response by limiting the bioavailability of iron by a number of mechanisms including the enhanced expression of hepcidin, the master iron-regulating hormone, which reduces iron uptake from the gut and retains iron in macrophages. The host also secretes the antibacterial protein NGAL, which sequesters bacterial siderophores and therefore inhibits bacterial growth. To learn whether intracellular gonococci can subvert this defensive response, we examined expression of host genes that encode proteins involved in modulating levels of intracellular iron. We found that N. gonorrhoeae can survive in association (tightly adherent and intracellular with monocytes and macrophages and upregulates a panel of its iron-responsive genes in this environment. We also found that gonococcal infection of human monocytes or murine macrophages resulted in the upregulation of hepcidin, NGAL, and NRAMP1 as well as downregulation of the expression of the gene encoding the short chain 3-hydroxybutyrate dehydrogenase (BDH2; BDH2 catalyzes the production of the mammalian siderophore 2,5-DHBA involved in chelating and detoxifying iron. Based on these findings, we propose that N. gonorrhoeae can subvert the iron-limiting innate immune defenses to facilitate iron acquisition and intracellular survival.

  17. Zebra chip-diseased potato tubers are characterized by increased levels of host secondary metabolites, amino acids, and defense-related proteins

    Science.gov (United States)

    Zebra chip disease, a serious threat to potato production in the United States and elsewhere, is associated with 'Cadidatus Liberibacter solacearum'. Little is known about host chemistry effects on zebra chip disease symptom development in potatoes (Solanum tuberosum). This research compared chemic...

  18. HostPhinder: A Phage Host Prediction Tool

    OpenAIRE

    Julia Villarroel; Kortine Annina Kleinheinz; Vanessa Isabell Jurtz; Henrike Zschach; Ole Lund; Morten Nielsen; Mette Voldby Larsen

    2016-01-01

    The current dramatic increase of antibiotic resistant bacteria has revitalised the interest in bacteriophages as alternative antibacterial treatment. Meanwhile, the development of bioinformatics methods for analysing genomic data places high-throughput approaches for phage characterization within reach. Here, we present HostPhinder, a tool aimed at predicting the bacterial host of phages by examining the phage genome sequence. Using a reference database of 2196 phages with known hosts, HostPh...

  19. Granuloma formation and host defense in chronic Mycobacterium tuberculosis infection requires PYCARD/ASC but not NLRP3 or caspase-1.

    Directory of Open Access Journals (Sweden)

    Erin McElvania Tekippe

    Full Text Available The NLR gene family mediates host immunity to various acute pathogenic stimuli, but its role in chronic infection is not known. This paper addressed the role of NLRP3 (NALP3, its adaptor protein PYCARD (ASC, and caspase-1 during infection with Mycobacterium tuberculosis (Mtb. Mtb infection of macrophages in culture induced IL-1beta secretion, and this requires the inflammasome components PYCARD, caspase-1, and NLRP3. However, in vivo Mtb aerosol infection of Nlrp3(-/-, Casp-1(-/-, and WT mice showed no differences in pulmonary IL-1beta production, bacterial burden, or long-term survival. In contrast, a significant role was observed for Pycard in host protection during chronic Mtb infection, as shown by an abrupt decrease in survival of Pycard(-/- mice. Decreased survival of Pycard(-/- animals was associated with defective granuloma formation. These data demonstrate that PYCARD exerts a novel inflammasome-independent role during chronic Mtb infection by containing the bacteria in granulomas.

  20. The Bark-Beetle-Associated Fungus, Endoconidiophora polonica, Utilizes the Phenolic Defense Compounds of Its Host as a Carbon Source1[OPEN

    Science.gov (United States)

    Wadke, Namita; Kandasamy, Dineshkumar; Vogel, Heiko; Wingfield, Brenda D.; Paetz, Christian

    2016-01-01

    Norway spruce (Picea abies) is periodically attacked by the bark beetle Ips typographus and its fungal associate, Endoconidiophora polonica, whose infection is thought to be required for successful beetle attack. Norway spruce produces terpenoid resins and phenolics in response to fungal and bark beetle invasion. However, how the fungal associate copes with these chemical defenses is still unclear. In this study, we investigated changes in the phenolic content of Norway spruce bark upon E. polonica infection and the biochemical factors mediating these changes. Although genes encoding the rate-limiting enzymes in Norway spruce stilbene and flavonoid biosynthesis were actively transcribed during fungal infection, there was a significant time-dependent decline of the corresponding metabolites in fungal lesions. In vitro feeding experiments with pure phenolics revealed that E. polonica transforms both stilbenes and flavonoids to muconoid-type ring-cleavage products, which are likely the first steps in the degradation of spruce defenses to substrates that can enter the tricarboxylic acid cycle. Four genes were identified in E. polonica that encode catechol dioxygenases carrying out these reactions. These enzymes catalyze the cleavage of phenolic rings with a vicinal dihydroxyl group to muconoid products accepting a wide range of Norway spruce-produced phenolics as substrates. The expression of these genes and E. polonica utilization of the most abundant spruce phenolics as carbon sources both correlated positively with fungal virulence in several strains. Thus, the pathways for the degradation of phenolic compounds in E. polonica, initiated by catechol dioxygenase action, are important to the infection, growth, and survival of this bark beetle-vectored fungus and may play a major role in the ability of I. typographus to colonize spruce trees. PMID:27208235

  1. Plant Defense against Insect Herbivores

    Directory of Open Access Journals (Sweden)

    Søren Bak

    2013-05-01

    Full Text Available Plants have been interacting with insects for several hundred million years, leading to complex defense approaches against various insect feeding strategies. Some defenses are constitutive while others are induced, although the insecticidal defense compound or protein classes are often similar. Insect herbivory induce several internal signals from the wounded tissues, including calcium ion fluxes, phosphorylation cascades and systemic- and jasmonate signaling. These are perceived in undamaged tissues, which thereafter reinforce their defense by producing different, mostly low molecular weight, defense compounds. These bioactive specialized plant defense compounds may repel or intoxicate insects, while defense proteins often interfere with their digestion. Volatiles are released upon herbivory to repel herbivores, attract predators or for communication between leaves or plants, and to induce defense responses. Plants also apply morphological features like waxes, trichomes and latices to make the feeding more difficult for the insects. Extrafloral nectar, food bodies and nesting or refuge sites are produced to accommodate and feed the predators of the herbivores. Meanwhile, herbivorous insects have adapted to resist plant defenses, and in some cases even sequester the compounds and reuse them in their own defense. Both plant defense and insect adaptation involve metabolic costs, so most plant-insect interactions reach a stand-off, where both host and herbivore survive although their development is suboptimal.

  2. Cellular transcriptional profiling in influenza A virus-infected lung epithelial cells: The role of the nonstructural NS1 protein in the evasion of the host innate defense and its potential contribution to pandemic influenza

    Science.gov (United States)

    Geiss, Gary K.; Salvatore, Mirella; Tumpey, Terrence M.; Carter, Victoria S.; Wang, Xiuyan; Basler, Christopher F.; Taubenberger, Jeffery K.; Bumgarner, Roger E.; Palese, Peter; Katze, Michael G.; García-Sastre, Adolfo

    2002-08-01

    The NS1 protein of influenza A virus contributes to viral pathogenesis, primarily by enabling the virus to disarm the host cell type IFN defense system. We examined the downstream effects of NS1 protein expression during influenza A virus infection on global cellular mRNA levels by measuring expression of over 13,000 cellular genes in response to infection with wild-type and mutant viruses in human lung epithelial cells. Influenza A/PR/8/34 virus infection resulted in a significant induction of genes involved in the IFN pathway. Deletion of the viral NS1 gene increased the number and magnitude of expression of cellular genes implicated in the IFN, NF-B, and other antiviral pathways. Interestingly, different IFN-induced genes showed different sensitivities to NS1-mediated inhibition of their expression. A recombinant virus with a C-terminal deletion in its NS1 gene induced an intermediate cellular mRNA expression pattern between wild-type and NS1 knockout viruses. Most significantly, a virus containing the 1918 pandemic NS1 gene was more efficient at blocking the expression of IFN-regulated genes than its parental influenza A/WSN/33 virus. Taken together, our results suggest that the cellular response to influenza A virus infection in human lung cells is significantly influenced by the sequence of the NS1 gene, demonstrating the importance of the NS1 protein in regulating the host cell response triggered by virus infection.

  3. A cupin domain-containing protein with a quercetinase activity (VdQase regulates Verticillium dahliae’s pathogenicity and contributes to counteracting host defenses

    Directory of Open Access Journals (Sweden)

    Abdel eElHadrami

    2015-06-01

    Full Text Available We previously identified rutin as part of potato root responses to its pathogen Verticillium dahliae. Rutin was directly toxic to the pathogen at doses greater than 160 μM, a threshold below which many V. dahliae pathogenicity-related genes were up-regulated. We identified and characterized a cupin domain-containing protein (VdQase with a dioxygenase activity and a potential role in V. dahliae-potato interactions. The pathogenicity of VdQase knock-out mutants generated through Agrobacterium tumefasciens-mediated transformation was significantly reduced on susceptible potato cultivar Kennebec compared to wild type isolates. Fluorescence microscopy revealed a higher accumulation of flavonols in the stems of infected potatoes and a higher concentration of rutin in the leaves in response to the VdQase mutants as compared to wild type isolates. This, along with the HPLC characterization of high residual and non-utilized quercetin in presence of the knockout mutants, indicates the involvement of VdQase in the catabolism of quercetin and possibly other flavonols in planta. Quantification of Salicylic and Jasmonic Acids (SA, JA in response to the mutants versus wild type isolates revealed involvement of VdQase in the interference with signaling, suggesting a role in pathogenicity. It is hypothesized that the by-product of dioxygenation 2-protocatechuoylphloroglucinolcarboxylic acid, after dissociating into phloroglucinol and protocatechuoyl moieties, becomes a starting point for benzoic acid and SA, thereby interfering with the JA pathway and affecting the interaction outcome. These events may be key factors for V. dahliae in countering potato defenses and becoming notorious in the rhizosphere.

  4. Fighting a losing battle: vigorous immune response countered by pathogen suppression of host defenses in the chytridiomycosis-susceptible frog Atelopus zeteki.

    Science.gov (United States)

    Ellison, Amy R; Savage, Anna E; DiRenzo, Grace V; Langhammer, Penny; Lips, Karen R; Zamudio, Kelly R

    2014-07-01

    The emergence of the disease chytridiomycosis caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd) has been implicated in dramatic global amphibian declines. Although many species have undergone catastrophic declines and/or extinctions, others appear to be unaffected or persist at reduced frequencies after Bd outbreaks. The reasons behind this variance in disease outcomes are poorly understood: differences in host immune responses have been proposed, yet previous studies suggest a lack of robust immune responses to Bd in susceptible species. Here, we sequenced transcriptomes from clutch-mates of a highly susceptible amphibian, Atelopus zeteki, with different infection histories. We found significant changes in expression of numerous genes involved in innate and inflammatory responses in infected frogs despite high susceptibility to chytridiomycosis. We show evidence of acquired immune responses generated against Bd, including increased expression of immunoglobulins and major histocompatibility complex genes. In addition, fungal-killing genes had significantly greater expression in frogs previously exposed to Bd compared with Bd-naïve frogs, including chitinase and serine-type proteases. However, our results appear to confirm recent in vitro evidence of immune suppression by Bd, demonstrated by decreased expression of lymphocyte genes in the spleen of infected compared with control frogs. We propose susceptibility to chytridiomycosis is not due to lack of Bd-specific immune responses but instead is caused by failure of those responses to be effective. Ineffective immune pathway activation and timing of antibody production are discussed as potential mechanisms. However, in light of our findings, suppression of key immune responses by Bd is likely an important factor in the lethality of this fungus. PMID:24841130

  5. Pathogen-mediated proteolysis of the cell death regulator RIPK1 and the host defense modulator RIPK2 in human aortic endothelial cells.

    Directory of Open Access Journals (Sweden)

    Andrés G Madrigal

    Full Text Available Porphyromonas gingivalis is the primary etiologic agent of periodontal disease that is associated with other human chronic inflammatory diseases, including atherosclerosis. The ability of P. gingivalis to invade and persist within human aortic endothelial cells (HAEC has been postulated to contribute to a low to moderate chronic state of inflammation, although how this is specifically achieved has not been well defined. In this study, we demonstrate that P. gingivalis infection of HAEC resulted in the rapid cleavage of receptor interacting protein 1 (RIPK1, a mediator of tumor necrosis factor (TNF receptor-1 (TNF-R1-induced cell activation or death, and RIPK2, a key mediator of both innate immune signaling and adaptive immunity. The cleavage of RIPK1 or RIPK2 was not observed in cells treated with apoptotic stimuli, or cells stimulated with agonists to TNF-R1, nucleotide oligomerization domain receptor 1(NOD1, NOD2, Toll-like receptor 2 (TLR2 or TLR4. P. gingivalis-induced cleavage of RIPK1 and RIPK2 was inhibited in the presence of a lysine-specific gingipain (Kgp inhibitor. RIPK1 and RIPK2 cleavage was not observed in HAEC treated with an isogenic mutant deficient in the lysine-specific gingipain, confirming a role for Kgp in the cleavage of RIPK1 and RIPK2. Similar proteolysis of poly (ADP-ribose polymerase (PARP was observed. We also demonstrated direct proteolysis of RIPK2 by P. gingivalis in a cell-free system which was abrogated in the presence of a Kgp-specific protease inhibitor. Our studies thus reveal an important role for pathogen-mediated modification of cellular kinases as a potential strategy for bacterial persistence within target host cells, which is associated with low-grade chronic inflammation, a hallmark of pathogen-mediated chronic inflammatory disorders.

  6. Immune defense in leaf-cutting ants

    DEFF Research Database (Denmark)

    Armitage, Sophie A O; Broch, Jens F; Marín, Hermogenes Fernández;

    2011-01-01

    To ameliorate the impact of disease, social insects combine individual innate immune defenses with collective social defenses. This implies that there are different levels of selection acting on investment in immunity, each with their own trade-offs. We present the results of a cross......-fostering experiment designed to address the influences of genotype and social rearing environment upon individual and social immune defenses. We used a multiply mating leaf-cutting ant, enabling us to test for patriline effects within a colony, as well as cross-colony matriline effects. The worker's father influenced...... both individual innate immunity (constitutive antibacterial activity) and the size of the metapleural gland, which secretes antimicrobial compounds and functions in individual and social defense, indicating multiple mating could have important consequences for both defense types. However, the primarily...

  7. Antimicrobial peptides in echinoderm host defense.

    Science.gov (United States)

    Li, Chun; Blencke, Hans-Matti; Haug, Tor; Stensvåg, Klara

    2015-03-01

    Antimicrobial peptides (AMPs) are important effector molecules in innate immunity. Here we briefly summarize characteristic traits of AMPs and their mechanisms of antimicrobial activity. Echinoderms live in a microbe-rich marine environment and are known to express a wide range of AMPs. We address two novel AMP families from coelomocytes of sea urchins: cysteine-rich AMPs (strongylocins) and heterodimeric AMPs (centrocins). These peptide families have conserved preprosequences, are present in both adults and pluteus stage larvae, have potent antimicrobial properties, and therefore appear to be important innate immune effectors. Strongylocins have a unique cysteine pattern compared to other cysteine-rich peptides, which suggests a novel AMP folding pattern. Centrocins and SdStrongylocin 2 contain brominated tryptophan residues in their native form. This review also includes AMPs isolated from other echinoderms, such as holothuroidins, fragments of beta-thymosin, and fragments of lectin (CEL-III). Echinoderm AMPs are crucial molecules for the understanding of echinoderm immunity, and their potent antimicrobial activity makes them potential precursors of novel drug leads. PMID:25445901

  8. Host-Defense Activities of Cyclotides

    Directory of Open Access Journals (Sweden)

    David J. Craik

    2012-02-01

    Full Text Available Cyclotides are plant mini-proteins whose natural function is thought to be to protect plants from pest or pathogens, particularly insect pests. They are approximately 30 amino acids in size and are characterized by a cyclic peptide backbone and a cystine knot arrangement of three conserved disulfide bonds. This article provides an overview of the reported pesticidal or toxic activities of cyclotides, discusses a possible common mechanism of action involving disruption of biological membranes in pest species, and describes methods that can be used to produce cyclotides for potential applications as novel pesticidal agents.

  9. Tobacco smoke. Effects on pulmonary host defense.

    Science.gov (United States)

    Drath, D B; Karnovsky, M L; Huber, G L

    1979-07-01

    Tobacco smoke affected both the metabolism and function of pulmonary alveolar macrophages (PAM). Phagocytosis of viable Staphylococcus aureus and inert starch particles was minimally but consistently depressed in PAM from rats exposed to tobacco smoke for six months. Oxygen consumption, superoxide and hydrogen peroxide release, and hexose monophosphate shunt activity were elevated in cells from smokers. Oxidation of glucose, labelled in the carbon-six position, remained unchanged. All observed effects of tobacco smoke on oxygen metabolism occurred during phagocytosis and did not affect the basal metabolism of the nonstimulated cell. PMID:225267

  10. Antioxidative defense

    Directory of Open Access Journals (Sweden)

    Stevanović Jelka

    2011-01-01

    Full Text Available Free radicals occur constantly during metabolism and take part in numerous physiological processes, such as: intra-cellular and inter-cellular signalization, gene expression, removal of damaged or senescent cells, and control of the tone of blood vessels. However, there is an increased quantity of free radicals in situations of so-called oxidative stress, when they cause serious damage to cellular membranes (peroxidation of their lipids, damage of membrane proteins, and similar, to interior cellular protein molecules, as well as DNA molecules and carbohydrates. This is precisely why the organism has developed numerous mechanisms for removing free radicals and/or preventing their production. Some of these are enzyme-related and include superoxide-dismutase, catalase, glutathione-peroxidase, and others. Other, non-enzyme mechanisms, imply antioxidative activities of vitamins E and C, provitamin A, coenzyme Q, reduced glutation, and others. Since free radicals can leave the cell that has produced them and become dispersed throughout the body, in addition to antioxidative defense that functions within cellular structures, antioxidant extra-cellular defense has also been developed. This is comprised by: transferrin, lactoferrin, haptoglobin, hemopexin, ceruloplasmin, albumins, extra-cellular isoform SOD, extracellular glutathione-peroxidase, glucose, bilirubin, urates, and many other molecules.

  11. PROPERTIES OF ANTIBACTERIAL MEDICATIONS

    Directory of Open Access Journals (Sweden)

    Boyko N. N.

    2014-01-01

    Full Text Available The possibility to use vector algebra theory for quantitative description of antibacterial medications and comparison of their properties has been shown. Mathematic formulas for description of medications’ antibacterial action basing on data of simple to use well method have been presented. This method allows evaluation of medications’ antibacterial activity and opportunity to choose the most active ones, as well as compare them with each other. It is noted that medications of natural origin are inferior to those of synthetic origin as for their antibacterial activity, and new galenic medications possess the most antimicrobial properties. The prospects of this method for pharmacoeconomic analysis of medications conducted in order to chose optimal cost/quality ratio has been demonstrated.

  12. Effect of Exogenous Surfactant Therapy on the Innate Host Defense Systems%外源性PS应用对早产儿先天性免疫系统的影响

    Institute of Scientific and Technical Information of China (English)

    王成祥; 常绍鸿

    2013-01-01

    Objective To investigate the levels of T lymphocytes and NK cells in peripheral blood of preterm infants who were treated with exogenous pulmonary surfactants(exPS). Methods From Jun. 2011 to Jan. 2012, 15 cases of preterm infants who were treated with exPS, selected over the same period 6 cases of full-term healthy infants, peripheral blood T lymphocytes and NK cells were detected and compared. Results The results showed that CD3+, CD4+, NK, and the ratio of CD4+/CD8+ in preterm infants than that in the control group. All of that in post-surfactant were significantly higher than that in pre-surfactant. Conclusion In preterm infants, Treatment with exPS apparently stimulated the innate host defense systems.%  目的研究外源性肺表面活性物质(pulmonary surfactant,PS)的应用对早产儿先天性免疫系统的影响。方法2011年6月-2012年1月于本院住院应用PS治疗的早产儿共15人,测定其应用前、应用后3d血清内外周血T淋巴细胞亚群和NK细胞的活性,并以健康足月儿6名为对照组。结果早产儿应用PS前,血清CD3+、CD4+、NK细胞数量及CD4+/CD8+比值均低于对照组,差异有统计学意义;而CD8+T细胞高于对照组;早产儿应用PS后3天CD3+、CD4+、NK细胞数量及CD4+/CD8+比值均有明显升高,差异有统计学意义;CD8+T细胞减少。结论应用外源性PS可有效提高早产儿先天性免疫系统的功能。

  13. Osteopontin That Is Elevated in the Airways during COPD Impairs the Antibacterial Activity of Common Innate Antibiotics.

    Directory of Open Access Journals (Sweden)

    Anele Gela

    Full Text Available Bacterial infections of the respiratory tract contribute to exacerbations and disease progression in chronic obstructive pulmonary disease (COPD. There is also an increased risk of invasive pneumococcal disease in COPD. The underlying mechanisms are not fully understood but include impaired mucociliary clearance and structural remodeling of the airways. In addition, antimicrobial proteins that are constitutively expressed or induced during inflammatory conditions are an important part of the airway innate host defense. In the present study, we show that osteopontin (OPN, a multifunctional glycoprotein that is highly upregulated in the airways of COPD patients co-localizes with several antimicrobial proteins expressed in the airways. In vitro, OPN bound lactoferrin, secretory leukocyte peptidase inhibitor (SLPI, midkine, human beta defensin-3 (hBD-3, and thymic stromal lymphopoietin (TSLP but showed low or no affinity for lysozyme and LL-37. Binding of OPN impaired the antibacterial activity against the important bacterial pathogens Streptococcus pneumoniae and Pseudomonas aeruginosa. Interestingly, OPN reduced lysozyme-induced killing of S. pneumoniae, a finding that could be explained by binding of OPN to the bacterial surface, thereby shielding the bacteria. A fragment of OPN generated by elastase of P. aeruginosa retained some inhibitory effect. Some antimicrobial proteins have additional functions. However, the muramidase-activity of lysozyme and the protease inhibitory function of SLPI were not affected by OPN. Taken together, OPN can contribute to the impairment of innate host defense by interfering with the function of antimicrobial proteins, thus increasing the vulnerability to acquire infections during COPD.

  14. Active cyber defense: enhancing national cyber defense

    OpenAIRE

    Wong, Tiong Pern.

    2011-01-01

    With increased dependency on the Internet, cyber attacks are fast becoming an attractive option for state adversaries, in part because of the ease of hiding one's identity. In response, governments around the world are taking measures to improve their national cyber defenses. However, these defenses, which are generally passive in nature, have been insufficient to address the threat. This thesis explores the possibility of employing active cyber defenses to improve cyber defenses at the na...

  15. BUTYRATE-MEDIATED GENOMIC CHANGES INVOLVED IN NON-SPECIFIC HOST DEFENSES, MATRIX REMODELING AND THE IMMUNE RESPONSE IN THE RUMEN EPITHELIUM OF COWS AFFLICTED WITH SUBACUTE RUMINAL ACIDOSIS

    Directory of Open Access Journals (Sweden)

    Louis Dionissopoulos

    2013-01-01

    involved in Non-Specific Host Defense (NSHD, Remodeling or adaptation (RM and Immune Response (IR. Of the 49 genes tested by qRT-PCR, 9 (LCN2, MMP1, MUC16, GPX2, CSTA, FUT1, SERPINE2, BCAM, RAC3 were upregulated, 20 (MTOR, AKIRIN2, NFKBIZ, NFKB2, ACVR2A, LAMB1, FRS2, PPARD, LBP, NEDD4L, SGK1, DEDD2, MAP3K8, PARD6B, PLIN2, ADA, HPGD, FMO5, BMP6, TCHH were downregulated and 20 were unchanged due to butyrate administration in the proximal gastrointestinal tract. These results demonstrate the potential protective effect and molecular mechanisms involved in a novel butyrate treatment for inflammatory gastrointestinal conditions.

  16. HostPhinder: A Phage Host Prediction Tool.

    Science.gov (United States)

    Villarroel, Julia; Kleinheinz, Kortine Annina; Jurtz, Vanessa Isabell; Zschach, Henrike; Lund, Ole; Nielsen, Morten; Larsen, Mette Voldby

    2016-01-01

    The current dramatic increase of antibiotic resistant bacteria has revitalised the interest in bacteriophages as alternative antibacterial treatment. Meanwhile, the development of bioinformatics methods for analysing genomic data places high-throughput approaches for phage characterization within reach. Here, we present HostPhinder, a tool aimed at predicting the bacterial host of phages by examining the phage genome sequence. Using a reference database of 2196 phages with known hosts, HostPhinder predicts the host species of a query phage as the host of the most genomically similar reference phages. As a measure of genomic similarity the number of co-occurring k-mers (DNA sequences of length k) is used. Using an independent evaluation set, HostPhinder was able to correctly predict host genus and species for 81% and 74% of the phages respectively, giving predictions for more phages than BLAST and significantly outperforming BLAST on phages for which both had predictions. HostPhinder predictions on phage draft genomes from the INTESTI phage cocktail corresponded well with the advertised targets of the cocktail. Our study indicates that for most phages genomic similarity correlates well with related bacterial hosts. HostPhinder is available as an interactive web service [1] and as a stand alone download from the Docker registry [2]. PMID:27153081

  17. Gramicidin D enhances the antibacterial activity of fluoride

    OpenAIRE

    Nelson1, James W.; ZHOU, ZHIYUAN; Breaker, Ronald R.

    2014-01-01

    Fluoride is a toxic anion found in many natural environments. One of the major bacterial defenses against fluoride is the cell envelope, which limits passage of the membrane-impermeant fluoride anion. Accordingly, compounds that enhance the permeability of bacterial membranes to fluoride should also enhance fluoride toxicity. In this study, we demonstrate that the pore-forming antibiotic gramicidin D increases fluoride uptake in B. subtilis and that the antibacterial activity of this compound...

  18. Dynamic defense workshop : from research to practice.

    Energy Technology Data Exchange (ETDEWEB)

    Crosby, Sean Michael; Doak, Justin E.; Haas, Jason J.; Helinski, Ryan; Lamb, Christopher C.

    2013-02-01

    On September 5th and 6th, 2012, the Dynamic Defense Workshop: From Research to Practice brought together researchers from academia, industry, and Sandia with the goals of increasing collaboration between Sandia National Laboratories and external organizations, de ning and un- derstanding dynamic, or moving target, defense concepts and directions, and gaining a greater understanding of the state of the art for dynamic defense. Through the workshop, we broadened and re ned our de nition and understanding, identi ed new approaches to inherent challenges, and de ned principles of dynamic defense. Half of the workshop was devoted to presentations of current state-of-the-art work. Presentation topics included areas such as the failure of current defenses, threats, techniques, goals of dynamic defense, theory, foundations of dynamic defense, future directions and open research questions related to dynamic defense. The remainder of the workshop was discussion, which was broken down into sessions on de ning challenges, applications to host or mobile environments, applications to enterprise network environments, exploring research and operational taxonomies, and determining how to apply scienti c rigor to and investigating the eld of dynamic defense.

  19. Antibacterial Applications of Nanodiamonds

    Directory of Open Access Journals (Sweden)

    Sabine Szunerits

    2016-04-01

    Full Text Available Bacterial infectious diseases, sharing clinical characteristics such as chronic inflammation and tissue damage, pose a major threat to human health. The steady increase of multidrug-resistant bacteria infections adds up to the current problems modern healthcare is facing. The treatment of bacterial infections with multi-resistant germs is very difficult, as the development of new antimicrobial drugs is hardly catching up with the development of antibiotic resistant pathogens. These and other considerations have generated an increased interest in the development of viable alternatives to antibiotics. A promising strategy is the use of nanomaterials with antibacterial character and of nanostructures displaying anti-adhesive activity against biofilms. Glycan-modified nanodiamonds (NDs revealed themselves to be of great promise as useful nanostructures for combating microbial infections. This review summarizes the current efforts in the synthesis of glycan-modified ND particles and evaluation of their antibacterial and anti-biofilm activities.

  20. Antibacterial Applications of Nanodiamonds

    Science.gov (United States)

    Szunerits, Sabine; Barras, Alexandre; Boukherroub, Rabah

    2016-01-01

    Bacterial infectious diseases, sharing clinical characteristics such as chronic inflammation and tissue damage, pose a major threat to human health. The steady increase of multidrug-resistant bacteria infections adds up to the current problems modern healthcare is facing. The treatment of bacterial infections with multi-resistant germs is very difficult, as the development of new antimicrobial drugs is hardly catching up with the development of antibiotic resistant pathogens. These and other considerations have generated an increased interest in the development of viable alternatives to antibiotics. A promising strategy is the use of nanomaterials with antibacterial character and of nanostructures displaying anti-adhesive activity against biofilms. Glycan-modified nanodiamonds (NDs) revealed themselves to be of great promise as useful nanostructures for combating microbial infections. This review summarizes the current efforts in the synthesis of glycan-modified ND particles and evaluation of their antibacterial and anti-biofilm activities. PMID:27077871

  1. Antibacterial Au nanostructured surfaces

    Science.gov (United States)

    Wu, Songmei; Zuber, Flavia; Brugger, Juergen; Maniura-Weber, Katharina; Ren, Qun

    2016-01-01

    We present here a technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It was found that all the Au nanostructures, regardless their shapes, exhibited similar excellent antibacterial properties. A comparison of live cells attached to nanotopographic surfaces showed that the number of live S. aureus cells was technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It was found that all the Au nanostructures, regardless their shapes, exhibited similar excellent antibacterial properties. A comparison of live cells attached to nanotopographic surfaces showed that the number of live S. aureus cells was information (ESI) available. See DOI: 10.1039/c5nr06157a

  2. Antibacterial activity of Pterocarpus santalinus

    OpenAIRE

    Manjunatha B

    2006-01-01

    Antibacterial activity of leaf and stem bark of Pterocarpus santalinus (Fabaceae) was investigated. The antibacterial activity was tested against both Gram-positive and Gram-negative organisms. Among the two extracts tested, stem bark extract exhibited broad-spectrum antibacterial activity against the tested organisms. The stem bark extract showed maximum activity against Enterobacter aerogenes, Alcaligenes faecalis, Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris, Bacillus cere...

  3. Behavioral Strategies of Phorid Parasitoids and Responses of Their Hosts, the Leaf-Cutting Ants

    OpenAIRE

    Elizalde, Luciana; Folgarait, Patricia Julia

    2012-01-01

    Host-searching and oviposition behaviors of parasitoids, and defensive responses of the hosts, are fundamental in shaping the ecology of host-parasitoid interactions. In order to uncover key behavioral features for the little known interactions between phorid parasitoids (Diptera: Phoridae) and their leaf-cutting ant hosts (Formicidae: Attini), host-related behavioral strategies (i.e., host searching and oviposition) for 13 phorid species, and host defensive responses (i.e., hitchhikers and p...

  4. Understanding Defense Mechanisms.

    Science.gov (United States)

    Cramer, Phebe

    2015-12-01

    Understanding defense mechanisms is an important part of psychotherapy. In this article, we trace the history of the concept of defense, from its origin with Freud to current views. The issue of defense as an unconscious mechanism is examined. The question of whether defenses are pathological, as well as their relation to pathology, is discussed. The effect of psychotherapy on the use of defenses, and their relation to a therapeutic alliance is explored. A series of empirical research studies that demonstrate the functioning of defense mechanisms and that support the theory is presented. Research also shows that as part of normal development, different defenses emerge at different developmental periods, and that gender differences in defense use occur. PMID:26583439

  5. Antibacterial activities of antineoplastic agents.

    OpenAIRE

    Bodet, C A; Jorgensen, J H; Drutz, D J

    1985-01-01

    Fourteen antineoplastic agents were examined for in vitro antibacterial activity against 101 aerobic and anaerobic bacterial isolates representing indigenous human microflora and selected opportunistic pathogens. Only 5-fluorouracil, mitomycin, and etoposide demonstrated inhibitory effects at achievable plasma concentrations, while the remaining drugs lacked appreciable antibacterial activities.

  6. Innate defense regulator peptide 1018 in wound healing and wound infection.

    Directory of Open Access Journals (Sweden)

    Lars Steinstraesser

    Full Text Available Innate defense regulators (IDRs are synthetic immunomodulatory versions of natural host defense peptides (HDP. IDRs mediate protection against bacterial challenge in the absence of direct antimicrobial activity, representing a novel approach to anti-infective and anti-inflammatory therapy. Previously, we reported that IDR-1018 selectively induced chemokine responses and suppressed pro-inflammatory responses. As there has been an increasing appreciation for the ability of HDPs to modulate complex immune processes, including wound healing, we characterized the wound healing activities of IDR-1018 in vitro. Further, we investigated the efficacy of IDR-1018 in diabetic and non-diabetic wound healing models. In all experiments, IDR-1018 was compared to the human HDP LL-37 and HDP-derived wound healing peptide HB-107. IDR-1018 was significantly less cytotoxic in vitro as compared to either LL-37 or HB-107. Furthermore, administration of IDR-1018 resulted in a dose-dependent increase in fibroblast cellular respiration. In vivo, IDR-1018 demonstrated significantly accelerated wound healing in S. aureus infected porcine and non-diabetic but not in diabetic murine wounds. However, no significant differences in bacterial colonization were observed. Our investigation demonstrates that in addition to previously reported immunomodulatory activities IDR-1018 promotes wound healing independent of direct antibacterial activity. Interestingly, these effects were not observed in diabetic wounds. It is anticipated that the wound healing activities of IDR-1018 can be attributed to modulation of host immune pathways that are suppressed in diabetic wounds and provide further evidence of the multiple immunomodulatory activities of IDR-1018.

  7. Carbon Nanomaterials as Antibacterial Colloids

    Directory of Open Access Journals (Sweden)

    Michael Maas

    2016-07-01

    Full Text Available Carbon nanomaterials like graphene, carbon nanotubes, fullerenes and the various forms of diamond have attracted great attention for their vast potential regarding applications in electrical engineering and as biomaterials. The study of the antibacterial properties of carbon nanomaterials provides fundamental information on the possible toxicity and environmental impact of these materials. Furthermore, as a result of the increasing prevalence of resistant bacteria strains, the development of novel antibacterial materials is of great importance. This article reviews current research efforts on characterizing the antibacterial activity of carbon nanomaterials from the perspective of colloid and interface science. Building on these fundamental findings, recent functionalization strategies for enhancing the antibacterial effect of carbon nanomaterials are described. The review concludes with a comprehensive outlook that summarizes the most important discoveries and trends regarding antibacterial carbon nanomaterials.

  8. Molecular interactions between the specialist herbivore Manduca sexta (Lepidoptera, Sphingidae) and its natural host Nicotiana attenuata. I. Large-scale changes in the accumulation of growth- and defense-related plant mRNAs.

    Science.gov (United States)

    Hermsmeier, D; Schittko, U; Baldwin, I T

    2001-02-01

    Plants respond to herbivore attack with a dramatic functional reorganization that involves the activation of direct and indirect defenses and tolerance, which in turn make large demands on primary metabolism. Here we provide the first characterization of the transcriptional reorganization that occurs after insect attack in a model plant-herbivore system: Nicotiana attenuata Torr. ex Wats.-Manduca sexta. We used mRNA differential display to characterize one-twentieth of the insect-responsive transcriptome of N. attenuata and verified differential expression for 27 cDNAs. Northern analyses were used to study the effects of folivory and exposure to airborne methyl jasmonate and for kinetic analyses throughout a 16-h- light/8-h-dark cycle. Sequence similarity searches allowed putative functions to be assigned to 15 transcripts. Genes were related to photosynthesis, electron transport, cytoskeleton, carbon and nitrogen metabolism, signaling, and a group responding to stress, wounding, or invasion of pathogens. Overall, transcripts involved in photosynthesis were strongly down-regulated, whereas those responding to stress, wounding, and pathogens and involved in shifting carbon and nitrogen to defense were strongly up-regulated. The majority of transcripts responded similarly to airborne methyl jasmonate and folivory, and had tissue- and diurnal-specific patterns of expression. Transcripts encoding Thr deaminase (TD) and a putative retrotransposon were absent in control plants, but were strongly induced after herbivory. Full-length sequences were obtained for TD and the pathogen-inducible alpha-dioxygenase, PIOX. Effects of abiotic and biotic stimuli were investigated for transcripts encoding TD, importin alpha, PIOX, and a GAL83-like kinase cofactor. PMID:11161026

  9. Setting and Revising Antibacterial Susceptibility Breakpoints

    OpenAIRE

    Turnidge, John; PATERSON, DAVID L.

    2007-01-01

    Clinical microbiology laboratories need to communicate results of antibacterial susceptibility testing to prescribers. Sophisticated prescribers who are knowledgeable of the pharmacokinetics and pharmacodynamics of antibacterials may desire no more information than the MIC of the drug in question. However, most prescribers require interpretation of antibacterial susceptibility testing results. Breakpoints can assist in determining if an antibacterial is potentially useful in the treatment of ...

  10. Helical 1:1 α/Sulfono-γ-AA Heterogeneous Peptides with Antibacterial Activity.

    Science.gov (United States)

    She, Fengyu; Nimmagadda, Alekhya; Teng, Peng; Su, Ma; Zuo, Xiaobing; Cai, Jianfeng

    2016-05-01

    As one of the greatest threats facing the 21st century, antibiotic resistance is now a major public health concern. Host-defense peptides (HDPs) offer an alternative approach to combat emerging multi-drug-resistant bacteria. It is known that helical HDPs such as magainin 2 and its analogs adopt cationic amphipathic conformations upon interaction with bacterial membranes, leading to membrane disruption and subsequent bacterial cell death. We have previously shown that amphipathic sulfono-γ-AApeptides could mimic magainin 2 and exhibit bactericidal activity. In this article, we demonstrate for the first time that amphipathic helical 1:1 α/sulfono-γ-AA heterogeneous peptides, in which regular amino acids and sulfono-γ-AApeptide building blocks are alternatively present in a 1:1 pattern, display potent antibacterial activity against both Gram-positive and Gram-negative bacterial pathogens. Small angle X-ray scattering (SAXS) suggests that the lead sequences adopt defined helical structures. The subsequent studies including fluorescence microscopy and time-kill experiments indicate that these hybrid peptides exert antimicrobial activity by mimicking the mechanism of HDPs. Our findings may lead to the development of HDP-mimicking antimicrobial peptidomimetics that combat drug-resistant bacterial pathogens. In addition, our results also demonstrate the effective design of a new class of helical foldamer, which could be employed to interrogate other important biological targets such as protein-protein interactions in the future. PMID:27030636

  11. The Evolving Role of Chemical Synthesis in Antibacterial Drug Discovery

    OpenAIRE

    Wright, Peter M.; Seiple, Ian B.; Myers, Andrew G.

    2014-01-01

    The discovery and implementation of antibiotics in the early twentieth century transformed human health and wellbeing. Chemical synthesis enabled the development of the first antibacterial substances, organoarsenicals and sulfa drugs, but these were soon outshone by a host of more powerful and vastly more complex antibiotics from nature: penicillin, streptomycin, tetracycline, and erythromycin, among others. These primary defences are now significantly less effective as an unavoidable consequ...

  12. Takeover Defenses and Competition

    OpenAIRE

    Martijn Cremers; Vinay Nair; Urs Peyer

    2007-01-01

    This paper studies the interaction between takeover defenses and product market competition. We find that firms in more competitive industries have more takeover defenses. This is the opposite result from what one would expect if takeover defenses always constitute an inefficient outcome that increases agency costs and managerial entrenchment. A novel explantion is provided by considering the nature of the relationship between the firm and the product (or labor) market. For firms in industrie...

  13. Moving Target Defense

    CERN Document Server

    Jajodia, Sushil; Swarup, Vipin; Wang, Cliff; Wang, X Sean

    2011-01-01

    Moving Target Defense: Creating Asymmetric Uncertainty for Cyber Threats was developed by a group of leading researchers. It describes the fundamental challenges facing the research community and identifies new promising solution paths. Moving Target Defense which is motivated by the asymmetric costs borne by cyber defenders takes an advantage afforded to attackers and reverses it to advantage defenders. Moving Target Defense is enabled by technical trends in recent years, including virtualization and workload migration on commodity systems, widespread and redundant network connectivity, instr

  14. Norwegian cyber defense

    OpenAIRE

    Stensboel, Karl Birger

    2013-01-01

    Approved for public release; distribution is unlimited. This thesis postulates the need for a more proactive approach to cyber defense in Norway and offers recommendations about how Norway can be better prepared to counter cyber threats. It finds that Norways strategic infrastructure is vulnerable to cyber attacks and that Norway has no coherent strategy for meeting this challenge. The thesis argues that an effective cyber defense requires a wide range of offensive and defensive measures a...

  15. Antibacterial activity of Pterocarpus santalinus

    Directory of Open Access Journals (Sweden)

    Manjunatha B

    2006-01-01

    Full Text Available Antibacterial activity of leaf and stem bark of Pterocarpus santalinus (Fabaceae was investigated. The antibacterial activity was tested against both Gram-positive and Gram-negative organisms. Among the two extracts tested, stem bark extract exhibited broad-spectrum antibacterial activity against the tested organisms. The stem bark extract showed maximum activity against Enterobacter aerogenes, Alcaligenes faecalis, Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris, Bacillus cereus, Bacillus subtilis, Staphylococcus aureus . The leaf extract showed maximum activity against Escherichia coli, Alcaligenes faecalis, Enterobacter aerogenes and Pseudomonas aeruginosa . Both extracts exhibited concentration dependent activity.

  16. Defense Mechanisms: A Bibliography.

    Science.gov (United States)

    Pedrini, D. T.; Pedrini, Bonnie C.

    This bibliography includes studies of defense mechanisms, in general, and studies of multiple mechanisms. Defense mechanisms, briefly and simply defined, are the unconscious ego defendants against unpleasure, threat, or anxiety. Sigmund Freud deserves the clinical credit for studying many mechanisms and introducing them in professional literature.…

  17. Penitentiary integral defense

    Directory of Open Access Journals (Sweden)

    Francisco Javier Rodríguez Román

    2012-07-01

    Full Text Available Penitentiary integral defense is a set of techniques designed to solve the breach of the peace that may appear in the penitentiary world. This paper studies the scope and legal framework of penitentiary self-defense. This kind of self-defense is defined by the particular characteristics of a confinement context and a very specific regulation aimed at preserving the integrity of prisoners and penitentiary staff as well as prison facilities. A technical section illustrating the main penitentiary integral defense’s fundamentals and methods is also included. The defense methods showed here are: frisking, confinement cell entry, prisoner transfer, active resistance, aggressions between prisoners, standard defense equipment, handcuffs use, and techniques against holds, non-armed attacks and attacks with an edged weapon.

  18. Oral Immune Defense against Chronic Hyperplastic Candidosis

    OpenAIRE

    Musrati, Ahmed S Ali

    2008-01-01

    Candida yeast species are widespread opportunistic microbes, which are usually innocent opportunists unless the systemic or local defense system of the host becomes compromised. When they adhere on a fertile substrate such as moist and warm, protein-rich human mucosal membrane or biomaterial surface, they become activated and start to grow pseudo and real hyphae. Their growth is intricately guided by their ability to detect surface defects (providing secure hiding , thigmotropism) and nutrie...

  19. Integrated cyber defenses towards cyber defense doctrine

    OpenAIRE

    Cloud, Donald W.

    2007-01-01

    At the same time that the Department of Defense (DoD) has leveraged Network Centric Warfare concepts to increase the operational effectiveness of U.S. military forces and to gain decision superiority over adversaries, the DoD has become increasingly dependent upon the secure operations of computer networks and infrastructure. As a result, DoD computer network operations have become a vital center of gravity of U.S. military forces. Unfortunately, computer networks are growing faster than ...

  20. Unfolding Green Defense

    DEFF Research Database (Denmark)

    Larsen, Kristian Knus

    2015-01-01

    consumption in military operations, defense expenditure, energy security, and global climate change. The report then proceeds to introduce the NATO Green Defence Framework before exploring specific current uses of green technologies and green strategies for defense. The report concludes that a number of...... political, military, organizational, and technological challenges and possibilities are related to the development of green solutions for defense. Based on this conclusion the report argues that it is essential to comprehensively describe how a green solution is linked to a security challenge to develop...

  1. Auxins in defense strategies

    OpenAIRE

    Čarná, M. (Mária); Repka, V.; Skůpa, P. (Petr); Šturdík, E.

    2014-01-01

    Plant hormones operate in a very complex network where they regulate and control different vital mechanisms. They coordinate growth, development and defense via signaling involving different interactions of molecules. Activation of molecules responsible for regulation of plant immunity is mainly provided by salicylic and jasmonic acid signaling pathways. Similar to the signaling of these defense-associated plant hormones, auxin can also affect resistance to different pathogen groups and disea...

  2. PHENOMENON OF PSYCHOLOGICAL DEFENSE

    OpenAIRE

    Elena T. Sokolova

    2011-01-01

    The author discusses the controversial issues of formation and functioning of psychological defense mechanisms in ontogenesis and in personality disorders as they are represented in classical and contemporary psychoanalysis, in cognitivism and communication theory. The paper emphasizes the role of cognitive organization (style), sign-symbolic mediation, representative system of object relations and attachments in individual typological variability of the level organization of defense mechanis...

  3. Surfing China's National Defense

    Institute of Scientific and Technical Information of China (English)

    Ji Guilin

    2010-01-01

    @@ Following the start of its first test run on August 20, 2009, the website www.mod.gov.cn of the Ministry of National Defense (MOD) of the People's Republic of China has logged more than 2 billion hits,from many countries and regions including China, the United States,the United Kingdom, Japan, Australia and Singapore. China National Defense News reporters recently interviewed Ji Guilin, the website's Editor in Chief, on its performance and the feedback of netizens.

  4. Understanding Defensive Equity

    OpenAIRE

    Robert Novy-Marx

    2014-01-01

    High volatility and high beta stocks tilt strongly to small, unprofitable, and growth firms. These tilts explain the poor absolute performance of the most aggressive stocks. In conjunction with the well documented inability of the Fama and French three-factor model to price small growth stocks, especially unprofitable small growth stocks, these tilts also drive the abnormal performance of defensive equity (i.e., low volatility and/or low beta strategies). While defensive strategy performance ...

  5. Antibacterial Mechanism of Copper-bearing Antibacterial Stainless Steel against E.Coli

    Institute of Scientific and Technical Information of China (English)

    Li NAN; Weichao YANG; Yongqian LIU; Hui XU; Ying LI; Manqi L(U); Ke YANG

    2008-01-01

    A preliminary study was made on the antibacterial mechanism of copper-bearing antibacterial stainless steels against E.coli through experiments of microbiology such as EDTA (ethylenediaminetetraacetic acid) complex- ing, DNA smearing and AFM (atomic force microscope) observation. It was measured that the antibacterial stainless steels showed excellent antibacterial functions with antibacterial rate to E.coli over 99.99%. The antibacterial rate was weak if the bacteria solution was complexed by EDTA, indicating that the copper ions play a dominant role in the antibacterial effect of the antibacterial stainless steels. The electrophoresis experi- ment did not show the phenomenon of DNA smearing for E.coli after contacting antibacterial stainless steels, which meant that DNA of E.coli was not obviously damaged. It was observed by AFM that the morphology of E.coli changed a lot after contacting antibacterial stainless steels, such as cell walls being seriously changed and lots of contents in the cells being leaked.

  6. Antibacterial Cleaning Products and Drug Resistance

    OpenAIRE

    Aiello, Allison E.; Marshall, Bonnie; Levy, Stuart B.; Della-Latta, Phyllis; Lin, Susan X.; Larson, Elaine

    2005-01-01

    We examined whether household use of antibacterial cleaning and hygiene products is an emerging risk factor for carriage of antimicrobial drug–resistant bacteria on hands of household members. Households (N = 224) were randomized to use of antibacterial or nonantibacterial cleaning and hygiene products for 1 year. Logistic regression was used to assess the influence of antibacterial product use in homes. Antibacterial product use did not lead to a significant increase in antimicrobial drug re...

  7. Nest defenses and egg recognition of yellow-bellied prinia against cuckoo parasitism

    Science.gov (United States)

    Yang, Canchao; Wang, Longwu; Cheng, Shun-Jen; Hsu, Yu-Cheng; Liang, Wei; Møller, Anders Pape

    2014-09-01

    Parasites may, in multi-parasite systems, block the defenses of their hosts and thus thwart host recognition of parasites by frequency-dependent selection. Nest defenses as frontline may block or promote the subsequent stage of defenses such as egg recognition. We conducted comparative studies of the defensive strategies of a host of the Oriental cuckoo Cuculus optatus, the yellow-bellied prinia Prinia flaviventris, in mainland China with multiple species of cuckoos and in Taiwan with a single cuckoo species. Cuckoo hosts did not exhibit aggression toward cuckoos in the presence of multiple cuckoo species but showed strong aggressive defenses of hosts directed toward cuckoos in Taiwan. Furthermore, the cuckoo host in populations with a single cuckoo species was able to distinguish adults of its brood parasite, the Oriental cuckoo, from adult common cuckoos ( Cuculus canorus). This represents the first case in which a cuckoo host has been shown to specifically distinguish Oriental cuckoo, from other Cuculus species. Hosts ejected eggs at a higher rate in a single cuckoo species system than in a multi-species cuckoo system, which supports the strategy facilitation hypothesis. Granularity analysis of variation in egg phenotype based on avian vision modeling supported the egg signature hypothesis in hosts because Taiwanese prinias increased consistency in the appearance of their eggs within individual hosts thus favoring efficient discrimination against cuckoo eggs. This study significantly improves our knowledge of intraspecific variation in antiparasitism behavior of hosts between single- and multi-cuckoo systems.

  8. Antibacterial Properties of an Austenitic Antibacterial Stainless Steel and Its Security for Human Body

    Institute of Scientific and Technical Information of China (English)

    Ke YANG; Manqi L(U)

    2007-01-01

    An austenitic antibacterial stainless steel is reported in this paper. The very fine and dispersive ε-Cu precipitations in the matrix of the antibacterial steel after the antibacterial treatment endow the steel with antibacterial function. The antibacterial function is strong, long-term and broad-spectrum, and can be maintained even after repeated wear and long time dipping in water. The steel is safe for human body and could be used widely in daily application.

  9. Antibacterial Resistance Leadership Group: Open for Business

    OpenAIRE

    Chambers, Henry F.; Bartlett, John G.; Bonomo, Robert A.; Chiou, Christine; Cosgrove, Sara E.; CROSS, HEATHER R.; Daum, Robert S.; Downing, Michele; Evans, Scott R.; Knisely, Jane; Kreiswirth, Barry N.; Lautenbach, Ebbing; Mickley, Brenda S.; Patel, Robin; Pettigrew, Melinda M.

    2014-01-01

    The Antibacterial Resistance Leadership Group (ARLG) is tasked with prioritizing, designing, implementing, and conducting clinical studies to address antibacterial resistance. This article outlines clinical research resources and opportunities made available by ARLG and encourages submission of proposals that address antibacterial resistance.

  10. Defense-Inducing Volatiles: In Search of the Active Motif

    OpenAIRE

    Heil, Martin; Lion, Ulrich; Boland, Wilhelm

    2008-01-01

    Herbivore-induced volatile organic compounds (VOCs) are widely appreciated as an indirect defense mechanism since carnivorous arthropods use VOCs as cues for host localization and then attack herbivores. Another function of VOCs is plant–plant signaling. That VOCs elicit defensive responses in neighboring plants has been reported from various species, and different compounds have been found to be active. In order to search for a structural motif that characterizes active VOCs, we used lima be...

  11. Activation of Hepatic STAT3 Maintains Pulmonary Defense during Endotoxemia

    OpenAIRE

    Hilliard, Kristie L.; Allen, Eri; Traber, Katrina E.; Kim, Yuri; Wasserman, Gregory A.; Jones, Matthew R.; Mizgerd, Joseph P.; Quinton, Lee J.

    2015-01-01

    Pneumonia and infection-induced sepsis are worldwide public health concerns. Both pathologies elicit systemic inflammation and induce a robust acute-phase response (APR). Although APR activation is well regarded as a hallmark of infection, the direct contributions of liver activation to pulmonary defense during sepsis remain unclear. By targeting STAT3-dependent acute-phase changes in the liver, we evaluated the role of liver STAT3 activity in promoting host defense in the context of sepsis a...

  12. COP21: defense stakes

    International Nuclear Information System (INIS)

    The 21. Conference of the Parties (COP21) from the UN Framework Convention took place in Paris between November 30 and December 11, 2015. The challenge is to reach a universal agreement of fight against global warming and to control the carbon footprint of human activities. This topic is in the core of the Defense Ministry preoccupations. This special dossier takes stock of the question of defense issues linked with global warming. The dossier comprises 13 papers dealing with: 1 - COP21: defense stakes (Coldefy, A.); 2 - Warfare climate, a chance for peace (Hulot, N.); 3 - COP21 and defense (Aichi, L.); 4 - A war climate? (Tertrais, B.); 5 - Challenges the World has to face in the 21. century (Paillard, C.A.); 6 - Desertification: a time bomb in the heart of Sahel (Piodi, J.); 7 - The infrastructure department of defense in the fight against climate disturbance (Regnier, S.); 8 - Fight against global warming, a chance for the forces? (Volpi, J.L.); 9 - Sea and sustainable development (Descleves, E.); 10 - Rationales of Arctic's surrounding powers (Garcin, T.); 11 - Arctic: strategic stake (Granholm, N.; Wedin, L.); 12 - Strategic impact of Turkey's new energy choices (Pouvreau, A.); 13 - Climate and war: a brief historical outlook (Henninger, L.)

  13. Nanoparticles Encapsulated with LL37 and Serpin A1 Promotes Wound Healing and Synergistically Enhances Antibacterial Activity.

    Science.gov (United States)

    Fumakia, Miral; Ho, Emmanuel A

    2016-07-01

    Wound care is a serious healthcare concern, often complicated by prolonged inflammation and bacterial infection, which contributes significantly to mortality and morbidity. Agents commonly used to treat chronic wound infections are limited due to toxicity of the therapy, multifactorial etiology of chronic wounds, deep skin infections, lack of sustained controlled delivery of drugs, and development of drug resistance. LL37 is an endogenous host defense peptide possessing antimicrobial activity and is involved in the modulation of wound healing. Serpin A1 (A1) is an elastase inhibitor and has been shown to demonstrate wound-healing properties. Hence, our goal was to develop a topical combination nanomedicine for the controlled sustained delivery of LL37 and A1 at precise synergistic ratio combinations that will significantly promote wound closure, reduce bacterial contamination, and enhance anti-inflammatory activity. We have successfully developed the first solid lipid nanoparticle (SLN) formulation that can simultaneously deliver LL37 and A1 at specific ratios resulting in accelerated wound healing by promoting wound closure in BJ fibroblast cells and keratinocytes as well as synergistically enhancing antibacterial activity against S. aureus and E. coli in comparison to LL37 or A1 alone. PMID:27182713

  14. Antibacterial activity of the sponge Ircinia ramosa: Importance of its surface-associated bacteria

    Digital Repository Service at National Institute of Oceanography (India)

    Thakur, N.L.; Anil, A.C.

    inhibition by epibiota by Aus- tralian seaweeds. Biofouling 12:227–244. STIERLE, A. C., CARDELLINA, J. H., II, and SINGLETON, F. L. 1988. Marine Micrococcus produces metabolites ascribed to the sponge Tedania ignis. Experientia 44:1021. THOMPSON, J. E..., Ircinia ramosa, sponge-associated bacteria, fouling bacteria, epibiosis, chemical defense, antibacterial activity, nonpolar compounds, polar compounds. *To whom correspondence should be addressed. e-mail: acanil@csnio.ven.nic.in; acanil...

  15. Defensive Disclosure under Antitrust Enforcement

    OpenAIRE

    Bhaskarabhatla, Ajay; Pennings, Enrico

    2012-01-01

    textabstractWe formulate a simple model of optimal defensive disclosure by a monopolist facing uncertain antitrust enforcement and test its implications using unique data on defensive disclosures and patents by IBM during 1955-1989. Our results indicate that stronger antitrust enforcement leads to more defensive disclosure, that quality inventions are disclosed defensively, and that defensive disclosure served as an alternative but less successful mechanism to patenting at IBM in appropriatin...

  16. Defensive Disclosure under Antitrust Enforcement

    OpenAIRE

    Bhaskarabhatla, Ajay; Pennings, Enrico

    2012-01-01

    We formulate a simple model of optimal defensive disclosure by a dominant firm facing uncertain antitrust enforcement and test its implications using unique data on defensive disclosures and patents by IBM. Our results indicate that stronger antitrust enforcement leads to more defensive disclosure, that quality inventions are also disclosed defensively, and that defensive disclosure served as an alternative, but less successful, mechanism to patenting at IBM in appropriating returns from R&D....

  17. Defense waste management plan

    International Nuclear Information System (INIS)

    Defense high-level waste (HLW) and defense transuranic (TRU) waste are in interim storage at three sites, namely: at the Savannah River Plant, in South Carolina; at the Hanford Reservation, in Washington; and at the Idaho National Engineering Laboratory, in Idaho. Defense TRU waste is also in interim storage at the Oak Ridge National Laboratory, in Tennessee; at the Los Alamos National Laboratory, in New Mexico; and at the Nevada Test Site, in Nevada. (Figure E-2). This document describes a workable approach for the permanent disposal of high-level and transuranic waste from atomic energy defense activities. The plan does not address the disposal of suspect waste which has been conservatively considered to be high-level or transuranic waste but which can be shown to be low-level waste. This material will be processed and disposed of in accordance with low-level waste practices. The primary goal of this program is to utilize or dispose of high-level and transuranic waste routinely, safely, and effectively. This goal will include the disposal of the backlog of stored defense waste. A Reference Plan for each of the sites describes the sequence of steps leading to permanent disposal. No technological breakthroughs are required to implement the reference plan. Not all final decisions concerning the activities described in this document have been made. These decisions will depend on: completion of the National Environmental Policy Act process, authorization and appropriation of funds, agreements with states as appropriate, and in some cases, the results of pilot plant experiments and operational experience. The major elements of the reference plan for permanent disposal of defense high-level and transuranic waste are summarized

  18. 75 FR 76423 - Defense Intelligence Agency National Defense Intelligence College Board of Visitors Closed Meeting

    Science.gov (United States)

    2010-12-08

    ... of the Secretary Defense Intelligence Agency National Defense Intelligence College Board of Visitors Closed Meeting AGENCY: National Defense Intelligence College, Defense Intelligence Agency, Department of... a closed meeting of the Defense Intelligence Agency National Defense Intelligence College Board...

  19. 76 FR 28960 - Defense Intelligence Agency National Defense Intelligence College Board of Visitors Closed Meeting

    Science.gov (United States)

    2011-05-19

    ... of the Secretary Defense Intelligence Agency National Defense Intelligence College Board of Visitors Closed Meeting AGENCY: National Defense Intelligence College, Defense Intelligence Agency, Department of... a closed meeting of the Defense Intelligence Agency National Defense Intelligence College Board...

  20. Auxins in defense strategies

    Czech Academy of Sciences Publication Activity Database

    Čarná, Mária; Repka, V.; Skůpa, Petr; Šturdík, E.

    2014-01-01

    Roč. 69, č. 10 (2014), s. 1255-1263. ISSN 0006-3088 R&D Projects: GA TA ČR TA01011802 Institutional support: RVO:61389030 Keywords : auxin * defense responses * JA Subject RIV: GF - Plant Pathology, Vermin, Weed, Plant Protection Impact factor: 0.827, year: 2014

  1. Hanford defense waste studies

    International Nuclear Information System (INIS)

    PNL is assisting Rockwell Hanford Operations to prepare a programmatic environmental impact statement for the management of Hanford defense nuclear waste. The Ecological Sciences Department is leading the task of calculation of public radiation doses from a large matrix of potential routine and accidental releases of radionuclides to the environment

  2. Bioassay Guided Isolation of Antibacterial Compounds from Andrographis paniculata

    Directory of Open Access Journals (Sweden)

    A. Sule

    2011-01-01

    Full Text Available Problem statement: Chronic disease-causing bacteria of medical importance have developed resistance to antibiotics, hence, necessitating distinct and constant need for safe and efficient therapeutic agents. Plants are considered potent candidate for this aim. A way out of reducing antibiotic resistance and adverse effects on host is the employment of antibiotic resistance inhibitors of plant origin. Approach: About 5 kg pulverized Andrographis paniculata whole plant was macerated with MeOH at room temperature to get 305 g freeze dried MeOH extract. The bioautography of MeOH extract using Staphylococcus aureus and Proteus mirabilis as indicator organisms revealed the presence of two potent antibacterial compounds. MeOH extract was further fractionated and purified by silica gel column chromatography which led to the isolation of a diterpene lactone and an entlabdane diterpene glycoside upon crystallization with absolute ethanol. Results: Two antibacterial compounds viz., 3-O-β-D-glucosyl-14-deoxyandrographolide and 14-deoxyandrographolide were successfully isolated and characterized. Their structures were exclusively elucidated through spectroscopic methods (UV, IR, 1H- and 13C NMR. Conclusion: A. paniculata possesses antibacterial activity and could be potential source of a new class of antibiotics that might be useful for infectious disease chemotherapy and control.

  3. Cdc42 promotes host defenses against fatal infection

    DEFF Research Database (Denmark)

    Lee, Keunwook; Boyd, Kelli L; Parekh, Diptiben V;

    2013-01-01

    The small Rho GTPase, Cdc42, regulates key signaling pathways required for multiple cell functions including maintenance of shape, polarity, proliferation, invasion, migration, differentiation and morphogenesis. As the role of Cdc42-dependent signaling in fibroblasts in vivo is unknown, we...... attempted to specifically delete it in these cells by crossing the Cdc42(fl/fl) mouse with a FSP-1 cre mouse, which is thought to mediate recombination exclusively in fibroblasts. Surprisingly, the FSP-1cre;Cdc42(fl/fl) mice died at 3 weeks of age due to overwhelming suppurative upper airway infections that...... were associated with neutrophilia and lymphopenia. Even though major aberrations in lymphoid tissue development were present in the mice, the principal cause of death was severe migration and killing abnormalities of the neutrophil population resulting in an inability to control infection. We also...

  4. Modification of FMDV anti-host defense mechanism

    DEFF Research Database (Denmark)

    Guan, Suhua; Belsham, Graham

    Foot-and-mouth disease virus (FMDV) is the etiologic agent of FMD, an infectious and sometimes fatal viral disease that affects cloven-hoofed animals. The FMDV genome encodes a large polyprotein, the first component of which is the Leader protein. Unusually, within the picornavirus family, the FMDV...

  5. The bacteriome-mycobiome interaction and antifungal host defense

    NARCIS (Netherlands)

    Oever, J.T.; Netea, M.G.

    2014-01-01

    Large communities of microorganisms, collectively termed the microbiome, inhabit our body surfaces. With the advent of next-generation sequencing, the diversity and abundance of these communities are being unravelled. Besides an imporant role in metabolic processes, the microbiome is essential for p

  6. Bordetella adenylate cyclase toxin: a swift saboteur of host defense

    Czech Academy of Sciences Publication Activity Database

    Vojtová, Jana; Kamanová, Jana; Šebo, Peter

    2006-01-01

    Roč. 9, - (2006), s. 1-7. ISSN 1369-5274 R&D Projects: GA AV ČR IAA5020406; GA MŠk 1M0506 Institutional research plan: CEZ:AV0Z50200510 Keywords : cyaa * scanning electron microscopy * cyclase toxin Subject RIV: EE - Microbiology, Virology Impact factor: 7.445, year: 2006

  7. Osteopontin promotes host defense during Klebsiella pneumoniae-induced pneumonia

    NARCIS (Netherlands)

    G.J.W. van der Windt; J.J. Hoogerwerf; A.F. de Vos; S. Florquin; T. van der Poll

    2010-01-01

    Klebsiella pneumoniae is a common cause of nosocomial pneumonia. Osteopontin (OPN) is a phosphorylated glycoprotein involved in inflammatory processes, some of which is mediated by CD44. The aim of this study was to determine the role of OPN during K. pneumoniae-induced pneumonia. Wild-type (WT) and

  8. Defense styles of pedophilic offenders.

    Science.gov (United States)

    Drapeau, Martin; Beretta, Véronique; de Roten, Yves; Koerner, Annett; Despland, Jean-Nicolas

    2008-04-01

    This pilot study investigated the defense styles of pedophile sexual offenders. Interviews with 20 pedophiles and 20 controls were scored using the Defense Mechanisms Rating Scales. Results showed that pedophiles had a significantly lower overall defensive functioning score than the controls. Pedophiles used significantly fewer obsessional-level defenses but more major image-distorting and action-level defenses. Results also suggested differences in the prevalence of individual defenses where pedophiles used more dissociation, displacement, denial, autistic fantasy, splitting of object, projective identification, acting out, and passive aggressive behavior but less intellectualization and rationalization. PMID:17875603

  9. Inactivation of indispensable bacterial proteins by early proteins of bacteriophages: implication in antibacterial drug discovery.

    Science.gov (United States)

    Sau, S; Chattoraj, P; Ganguly, T; Chanda, P K; Mandal, N C

    2008-06-01

    Bacteriophages utilize host bacterial cellular machineries for their own reproduction and completion of life cycles. The early proteins that phage synthesize immediately after the entry of their genomes into bacterial cells participate in inhibiting host macromolecular biosynthesis, initiating phage-specific replication and synthesizing late proteins. Inhibition of synthesis of host macromolecules that eventually leads to cell death is generally performed by the physical and/or chemical modification of indispensable host proteins by early proteins. Interestingly, most modified bacterial proteins were shown to take part actively in phage-specific transcription and replication. Research on phages in last nine decades has demonstrated such lethal early proteins that interact with or chemically modify indispensable host proteins. Among the host proteins inhibited by lethal phage proteins, several are not inhibited by any chemical inhibitor available today. Under the context of widespread dissemination of antibiotic-resistant strains of pathogenic bacteria in recent years, the information of lethal phage proteins and cognate host proteins could be extremely invaluable as they may lead to the identification of novel antibacterial compounds. In this review, we summarize the current knowledge about some early phage proteins, their cognate host proteins and their mechanism of action and also describe how the above interacting proteins had been exploited in antibacterial drug discovery. PMID:18537683

  10. Two Dioryctria Species with Different Survival Strategies to Adapt to Chemical Defense of Host Plant Pinus koraiensis%红松的化学防御及冷杉梢斑螟和赤松梢斑螟的生存策略

    Institute of Scientific and Technical Information of China (English)

    王琪; 严善春; 徐波

    2012-01-01

    Dioryctria abietella and D. sylvestrella are close relative species in the same genus, and both endanger cones of Pinus koraiensis concomitantly, but their biological and ecological behaviors are quite different. To investigate the interactions between the host P. koraiensis chemical defense and physiological adaptation of the two D. species, we analyzed the larvae midgut detoxication enzymes and protective enzymes activities in lth, 3rd, Sth instars, and the defense enzymes in healthy, fed pine cones or top shoots at the corresponding period. The results showed that phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), peroxidase (POD), superoxide dismutase (SOD), catalase (CAT) activities in healthy cones and shoots were changed with the development stage. The two D. larvae feeding induced those defense enzymes activities significantly increased compared with healthy cones or tips. Detoxication enzymes and protective enzymes in the two D. species, which have different survival strategies, were quite different. D. abietella specifically fed on cone through larval stage, and their detoxication enzymes, S-transferase (GST), carboxylesterase (CarE), multi-function oxidase (MFO) in midgut were significantly higher than D. sylvestrella larvae that alternatively fed on cones and tips. There were no significant differences in superoxide dismutase (SOD) and chitinase (CT) activities in D. abietella and D. sylvestrella midgus, and the two protective enzymes activities were not related to whether transferred feeding. Phenoloxidase (PO) and peroxidase (POD) in D. sylvestrella midguts had higher activity compared with D. abietella, suggesting that the higher activity could facilitate them to avoid the threat of the transfer process. The results indicated that the physiological detoxification was the predominant survival strategies for D. abietella larvae to adapt to chemical defense of host plant, whereas D. sylvestrella larvae survived not only by carrying out the

  11. Antibacterial potency screening of Capparis zeylanica Linn

    Institute of Scientific and Technical Information of China (English)

    Rezaul Haque; Wahedul Islam; Selina Parween

    2016-01-01

    Objective: To conduct the antibacterial potency and minimum inhibitory concentration of extracts (n-hexane, acetone, chloroform and methanol) obtained from the root, leaf and stem of Capparis zeylanica. Methods: The powdered leaf, root and stem samples were Soxhlet extracted sequentially in n-hexane, acetone, chloroform and methanol. Antibacterial potency was evaluated by following the agar diffusion method and amoxicillin disc was used as a control. Results: In vitro antibacterial activity against 12 bacteria was performed with crude extracts. Among them, all the bacteria showed the moderate activity but chloroform and methanolic extracts showed promising antibacterial potency against Staphylococcus aureus, Sarcina lutea, Bacillus megaterium, Bacillus subtilis, Salmonella typhi and Shigella dysenteriae (leaf > root > stem). This activity was evaluated using disc diffusion method with a standard antibiotic, 30 µg/disc of amoxicillin. Conclusions: Strong antibacterial potency of chloroform and methanolic extracts provides new antibacterial compounds.

  12. EVALUATION OF ANTIBACTERIAL STUDIES IN HARSINGAAR

    Directory of Open Access Journals (Sweden)

    Ashish Kant Jain

    2013-07-01

    Full Text Available Plants are rich source of antibacterial agents, which could be control human diseases. Present investigation was an undertaken to evaluate the antibacterial of Harsinger (Nyctanthes arbortristis Linn against five important human pathogenic bacteria i.e. Escherichia coli, Staphylococcus aureus, Proteus vulgaris, Salmonella typhimurium and Pseudomonas aueruginosa by filter paper disc diffusion method. Dried leaves of Nyctanthes arbortristis were collected, washed, shade dried and powdered. Aqueous and methanol extracts were prepared and evaluate their antibacterial activity. The significant result of antibacterial activity was observed in aqueous as well as methanol leaves extract. The strongest antibacterial activity of aqueous leaves extract was observed in Pseudomonas aeruginosa with (22.00 mm zone of inhibition while the methanol leaves extract showed strongest antibacterial activity against Staphylococcus aureus with (28.00 mm maximum zone of inhibition.

  13. Bacillus anthracis and antibacterial agents.

    Science.gov (United States)

    Bryskier, A

    2002-08-01

    Anthrax is one of the oldest threats to humankind, and remains endemic in animals in many parts of the world. Human cases are infrequent, and some result from biological warfare. This review summarizes the current knowledge on the antibacterial activity of available antibiotics. For potential use in the most severe cases of anthrax, antibacterials need to exhibit potent in vitro activity, intracellular bioactivity, and suitable locations in lymph nodes. In animal models, it has been shown that doxycycline and fluoroquinolones are the most active compounds. There is a lack of data for animal models for macrolides and ketolides, some of them exhibiting good in vitro activity. However, systemic anthrax (inhalation or gastrointestinal) is mainly due to anthrax toxin, and therapy directed against intoxication is needed as basic treatment. PMID:12197869

  14. Washable and antibacterial superhydrophbic fabric

    Science.gov (United States)

    Ou, Junfei; Wang, Zhile; Wang, Fajun; Xue, Mingshan; Li, Wen; Amirfazli, Alidad

    2016-02-01

    Inspired by the high adherence of mussel and the excellent water repellency of lotus leaf, superhydrophobic fabric is fabricated via the sequential deposition of polydopamine, Ag2O, and 1H,1H,2H,2H-perfluorodecanethiol, which shows excellent washability and high anti-bacterial activity due to the strong interfacial interaction and the surface silver species as well as the non-wettability, respectively.

  15. Antibacterial potential of diamond nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Beranová, Jana; Seydlová, Gabriela; Kozak, Halyna; Benada, Oldřich; Fišer, Radovan; Artemenko, Anna; Konopásek, Ivo; Kromka, Alexander

    Ostrava: Tanger, 2014. ISBN 978-80-87294-55-0. [International Conference NANOCON /6./. 05.11.2014-07.11.2014, Brno] R&D Projects: GA ČR GAP108/12/0910 Institutional support: RVO:68378271 ; RVO:61388971 Keywords : diamond nanoparticles * antibacterial properties * Escherichia coli * Bacillus subtilis * DLS * XPS Subject RIV: BM - Solid Matter Physics ; Magnetism; EE - Microbiology, Virology (MBU-M)

  16. Natural antibacterial characteristics of honey

    OpenAIRE

    Pešić-Mikulec Dragana M.; Dugalić-Vrndić Nada; Baltić Milan Ž.

    2004-01-01

    Honey was used as a medicine in traditional medicine of the Ancient Times ever since the age of Hippocrates. Scientifically based investigations of the medicinal qualities of honey date back to the 19th century. There have been constant polemics, about the medicinal characteristics of honey and parameters that cause them, among scientists and apiculture experts. In this paper, we processed much data from literature, which indicate the antibacterial characteristics of honey through the experim...

  17. Indirect conductimetric assay of antibacterial activities.

    Science.gov (United States)

    Sawai, J; Doi, R; Maekawa, Y; Yoshikawa, T; Kojima, H

    2002-11-01

    The applicability of indirect conductimetric assays for evaluation of antibacterial activity was examined. The minimal inhibitory concentration (MIC) obtained by the indirect method was consistent with that by the direct conductimetric assay and the turbidity method. The indirect assay allows use of growth media, which cannot be used in the direct conductimetric assay, making it possible to evaluate the antibacterial activity of insoluble or slightly soluble materials with high turbidity, such as antibacterial ceramic powders. PMID:12407467

  18. Antibacterial phenolics from the mangrove Lumnitzera racemosa

    Digital Repository Service at National Institute of Oceanography (India)

    DeSouza, L.; Wahidullah, S.; PrabhaDevi

    and antifungal assays were performed using Agar well diffusion method2, 3 and MIC was determined by tube dilution method using Himedia Mueller-Hinton broth4. Streptomycin and nystatin were used as antibacterial and antifungal positive controls while solvent... reported the enhancement of antibacterial activity on mixing of quercetin with quercitrin, morin or rutin. There are conflicting reports on the antibacterial activity of quercetin probably owing to inter and intra-assay variation in susceptibility...

  19. Antibacterial and Antifungal Compounds from Marine Fungi

    OpenAIRE

    Lijian Xu; Wei Meng; Cong Cao; Jian Wang; Wenjun Shan; Qinggui Wang

    2015-01-01

    This paper reviews 116 new compounds with antifungal or antibacterial activities as well as 169 other known antimicrobial compounds, with a specific focus on January 2010 through March 2015. Furthermore, the phylogeny of the fungi producing these antibacterial or antifungal compounds was analyzed. The new methods used to isolate marine fungi that possess antibacterial or antifungal activities as well as the relationship between structure and activity are shown in this review.

  20. Amphibian immune defenses against chytridiomycosis: impacts of changing environments.

    Science.gov (United States)

    Rollins-Smith, Louise A; Ramsey, Jeremy P; Pask, James D; Reinert, Laura K; Woodhams, Douglas C

    2011-10-01

    Eco-immunology is the field of study that attempts to understand the functions of the immune system in the context of the host's environment. Amphibians are currently suffering devastating declines and extinctions in nearly all parts of the world due to the emerging infectious disease chytridiomycosis caused by the chytrid fungus, Batrachochytrium dendrobatidis. Because chytridiomycosis is a skin infection and remains confined to the skin, immune defenses of the skin are critical for survival. Skin defenses include secreted antimicrobial peptides and immunoglobulins as well as antifungal metabolites produced by symbiotic skin bacteria. Low temperatures, toxic chemicals, and stress inhibit the immune system and may impair natural defenses against B. dendrobatidis. Tadpoles' mouth parts can be infected by B. dendrobatidis. Damage to the mouth parts can impair growth, and the affected tadpoles maintain the pathogen in the environment even when adults have dispersed. Newly metamorphosing frogs appear to be especially vulnerable to infection and to the lethal effects of this pathogen because the immune system undergoes a dramatic reorganization at metamorphosis, and postmetamorphic defenses are not yet mature. Here we review our current understanding of amphibian immune defenses against B. dendrobatidis and the ability of the pathogen to resist those defenses. We also briefly review what is known about the impacts of temperature, environmental chemicals, and stress on the host-pathogen interactions and suggest future directions for research. PMID:21816807

  1. Cross talk in defense signaling

    OpenAIRE

    Koornneef, A.; Pieterse, C.M.J.

    2008-01-01

    Plants are equipped with an array of defense mechanisms to protect themselves against attack by herbivorous insects and microbial pathogens. Some of these defense mechanisms are preexisting, whereas others are only activated upon insect or pathogen invasion. Induced defense responses entail fitness costs. Therefore, plants possess elaborate regulatory mechanisms that efficiently coordinate the activation of attackerspecific defenses so that fitness costs are minimized, while optimal resistanc...

  2. Lysozyme-Based Antibacterial Nanomotors.

    Science.gov (United States)

    Kiristi, Melek; Singh, Virendra V; Esteban-Fernández de Ávila, Berta; Uygun, Murat; Soto, Fernando; Aktaş Uygun, Deniz; Wang, Joseph

    2015-09-22

    An effective and rapid bacterial killing nanotechnology strategy based on lysozyme-modified fuel-free nanomotors is demonstrated. The efficient antibacterial property of lysozyme, associated with the cleavage of glycosidic bonds of peptidoglycans present in the bacteria cell wall, has been combined with ultrasound (US)-propelled porous gold nanowire (p-AuNW) motors as biocompatible dynamic bacteria nanofighters. Coupling the antibacterial activity of the enzyme with the rapid movement of these p-AuNWs, along with the corresponding fluid dynamics, promotes enzyme-bacteria interactions and prevents surface aggregation of dead bacteria, resulting in a greatly enhanced bacteria-killing capability. The large active surface area of these nanoporous motors offers a significantly higher enzyme loading capacity compared to nonporous AuNWs, which results in a higher antimicrobial activity against Gram-positive and Gram-negative bacteria. Detailed characterization studies and control experiments provide useful insights into the underlying factors controlling the antibacterial performance of the new dynamic bacteria nanofighters. Rapid and effective killing of the Gram-positive Micrococcus lysodeikticus bacteria (69-84% within 1-5 min) is demonstrated. PMID:26308491

  3. Evolution of exocrine chemical defense in leaf beetles (Coleoptera: Chrysomelidae)

    OpenAIRE

    Pasteels, Jacques M.; Rowell-Rahier, Martine; Braekman, J.C.; Daloze, D.; Duffey, S.

    2009-01-01

    In this review we speculate on possible scenarios for the evolution of the very high diversity in chemical compounds liberated by exocrine glands of adults Chrysomelidae. Shift in host plant affinities and subsequent adaptation of the beetles to the plant toxins strongly influence the nature of the beetles' chemical defense.

  4. Animal Defenses against Infectious Agents: Is Damage Control More Important Than Pathogen Control?

    OpenAIRE

    Andrew F Read; Graham, Andrea L.; Lars Råberg

    2008-01-01

    The ability of hosts to withstand a given number of pathogens is a critical component of health. Now playing catch-up with plant biologists, animal biologists are starting to formally separate this form of defense from classical resistance.

  5. Plant defense against insect herbivores

    DEFF Research Database (Denmark)

    Fürstenberg-Hägg, Joel; Zagrobelny, Mika; Bak, Søren

    2013-01-01

    , defense compounds. These bioactive specialized plant defense compounds may repel or intoxicate insects, while defense proteins often interfere with their digestion. Volatiles are released upon herbivory to repel herbivores, attract predators or for communication between leaves or plants, and to induce...

  6. Defense Mechanisms in Group Counseling.

    Science.gov (United States)

    Clark, Arthur J.

    1992-01-01

    Presents considerations and strategies for conceptualizing, recognizing, and modifying defense mechanisms through the group counseling process. Provides awareness of defense mechanisms in planning for and implementation of group counseling, describes interaction patterns for identifying defenses among group participants, and clarifies modification…

  7. Defense on the Move: Ant-Based Cyber Defense

    Energy Technology Data Exchange (ETDEWEB)

    Fink, Glenn A.; Haack, Jereme N.; McKinnon, Archibald D.; Fulp, Errin W.

    2014-04-15

    Many common cyber defenses (like firewalls and IDS) are as static as trench warfare allowing the attacker freedom to probe them at will. The concept of Moving Target Defense (MTD) adds dynamism to the defender side, but puts the systems to be defended themselves in motion, potentially at great cost to the defender. An alternative approach is a mobile resilient defense that removes attackers’ ability to rely on prior experience without requiring motion in the protected infrastructure itself. The defensive technology absorbs most of the cost of motion, is resilient to attack, and is unpredictable to attackers. The Ant-Based Cyber Defense (ABCD) is a mobile resilient defense providing a set of roaming, bio-inspired, digital-ant agents working with stationary agents in a hierarchy headed by a human supervisor. The ABCD approach provides a resilient, extensible, and flexible defense that can scale to large, multi-enterprise infrastructures like the smart electric grid.

  8. Defense Mechanisms of Rosaceous Plants against Fire Blight Pathogen Erwinia amylovora

    OpenAIRE

    Vrancken, Kristof; HOLTAPPELS, Michelle; Valcke, Roland; Schoofs, H.; Deckers, T; Bylemans, D.

    2014-01-01

    Plants are host to an important amount of infectious diseases caused by a vast array of fungi, bacteria, viruses and nematodes. In great contrast to the mammalian immune system composed of specialized and mobile defense cells such as lymphocytes, plants have to rely on the ability of each cell to recognize a pathogen and the signals emanating from the infection site to generate several defense mechanisms, either in a preformed or an inducible way. Inducible defense responses are triggered whe...

  9. Immunity, suicide or both? Ecological determinants for the combined evolution of anti-pathogen defense systems

    OpenAIRE

    Iranzo, Jaime; Lobkovsky, Alexander E.; Wolf, Yuri I.; Koonin, Eugene V.

    2015-01-01

    Background Parasite-host arms race is one of the key factors in the evolution of life. Most cellular life forms, in particular prokaryotes, possess diverse forms of defense against pathogens including innate immunity, adaptive immunity and programmed cell death (altruistic suicide). Coevolution of these different but interacting defense strategies yields complex evolutionary regimes. Results We develop and extensively analyze a computational model of coevolution of different defense strategie...

  10. Colorado potato beetle manipulates plant defenses in local and systemic leaves

    OpenAIRE

    Chung, Seung Ho; Rosa, Cristina; Hoover, Kelli; Luthe, Dawn S; Felton, Gary W.

    2013-01-01

    Herbivore microbial associates can affect diverse interactions between plants and insect herbivores. Some insect symbionts enable herbivores to expand host plant range or to facilitate host plant use by modifying plant physiology. However, little attention has been paid to the role of herbivore-associated microbes in manipulating plant defenses. We have recently shown that Colorado potato beetle secrete the symbiotic bacteria to suppress plant defenses. The bacteria in oral secretions from th...

  11. Antibacterial activity of Pseudoalteromonas in the coral holobiont.

    Science.gov (United States)

    Shnit-Orland, Maya; Sivan, Alex; Kushmaro, Ariel

    2012-11-01

    Corals harbor diverse and abundant prokaryotic populations. Bacterial communities residing in the coral mucus layer may be either pathogenic or symbiotic. Some species may produce antibiotics as a method of controlling populations of competing microbial species. The present study characterizes cultivable Pseudoalteromonas sp. isolated from the mucus layer of different coral species from the northern Gulf of Eilat, Red Sea, Israel. Six mucus-associated Pseudoalteromonas spp. obtained from different coral species were screened for antibacterial activity against 23 tester strains. Five of the six Pseudoalteromonas strains demonstrated extracellular antibacterial activity against Gram-positive-but not Gram-negative-tester strains. Active substances secreted into the cell-free supernatant are heat-tolerant and inhibit growth of Bacillus cereus, Staphylococcus aureus, and of ten endogenous Gram-positive marine bacteria isolated from corals. The Pseudoalteromonas spp. isolated from Red sea corals aligned in a phylogenetic tree with previously isolated Pseudoalteromonas spp. of marine origin that demonstrated antimicrobial activity. These results suggest that coral mucus-associated Pseudoalteromonas may play a protective role in the coral holobiont's defense against potential Gram-positive coral pathogens. PMID:22767125

  12. Modulation of pulmonary defense mechanisms by acute exposures to nitrogen dioxide

    International Nuclear Information System (INIS)

    The effect of acute exposures to NO2 on the antibacterial defenses of the murine lung was assessed following inhalation challenges with Staphylococcus aureus, Proteus mirabilis, and Pasteurella pneumotropica. With S. aureus pulmonary antibacterial defenses were suppressed at NO2 levels of 4.0 ppm and greater. Exposure to 10.0 ppm enhanced the intrapulmonary killing of P. mirabilis which correlated with an increase in the phagocytic cell populations lavaged from the lungs; at 20.0 ppm bactericidal activity against P. mirabilis was impaired. Pulmonary antibacterial defenses against P. pneumotropica were impaired at 10.0 ppm which correlated with a decrease in the retrieved phagocytic lung cell population. Reversing the order of treatment (ie., NO2 exposure prior to bacterial challenge) raised the threshold concentration for NO2-induced impairment of intrapulmonary bacterial killing. With S. aureus the effect was not observed at 5.0 ppm but at 10.0 ppm and with P. mirabilis not at 20.0 ppm but at 30.0 ppm intrapulmonary killing was enhanced. Exposures up to 20.0 ppm of NO2 did not effect the physical translocation mechanisms of the lung as quantitated by declines in pulmonary radiotracer activity following aerogenic challenge with 32P-labeled staphylococci

  13. Inducible direct plant defense against insect herbivores: A review

    Institute of Scientific and Technical Information of China (English)

    Ming-Shun Chen

    2008-01-01

    Plants respond to insect herbivory with responses broadly known as direct defenses, indirect defenses, and tolerance. Direct defenses include all plant traits that affect susceptibility of host plants by themselves. Overall categories of direct plant defenses against insect herbivores include limiting food supply, reducing nutrient value, reducing preference, disrupting physical structures, and inhibiting chemical pathways of the attacking insect. Major known defense chemicals include plant secondary metabolites, protein inhibitors of insect digestive enzymes, proteases, lectins, amino acid deaminases and oxidases. Multiple factors with additive or even synergistic impact are usually involved in defense against a specific insect species, and factors of major importance to one insect species may only be of secondary importance or not effective at all against another insect species. Extensive qualitative and quantitative high throughput analyses of temporal and spatial variations in gene expression, protein level and activity, and metabolite concentration will accelerate not only the understanding of the overall mechanisms of direct defense, but also accelerate the identification of specific targets for enhancement of plant resistance for agriculture.

  14. Phenomenon of Psychological Defense

    Directory of Open Access Journals (Sweden)

    Elena T. Sokolova

    2011-01-01

    Full Text Available The author discusses the controversial issues of formation and functioning of psy¬chological defense mechanisms in ontogenesis and in personality disorders as they are represented in classical and contemporary psychoanalysis, in cognitivism and communication theory. The paper emphasizes the role of cognitive organi¬zation (style, sign-symbolic mediation, representative system of object relations and attachments in individual typological variability of the level organization of ciency of personal and social adaptation, in maturity and mental health of personality

  15. Antibacterial activity of selected Myanmar medicinal plants

    International Nuclear Information System (INIS)

    Thirteen plants which are traditionally used for the treatment of dysentery and diarrhoea in Myanmar were selected and tested for antibacterial activity by using agar disc diffusion technique. Polar and nonpolar solvents were employed for extraction of plants. The minimum inhibitory concentration (MIC) of the extracts with the most significant predominant activity were evaluated by plate dilution method. The plants Eugenia jambolana, Quisqualis indica, Leucaena glauca and Euphorbia splendens var. 1 were found to show significant antibacterial activity. It was also observed that extracts using nonpolar solvents did not show any antibacterial activity and extracts using polar solvents showed antibacterial activity on tested bacteria, indicating that the active chemical compound responsible for the antibacterial action must be a polar soluble compound. (author)

  16. DEFENSE PROGRAMS RISK MANAGEMENT FRAMEWORK

    Directory of Open Access Journals (Sweden)

    Constantin PREDA

    2012-01-01

    Full Text Available For the past years defense programs have faced delays in delivering defense capabilities and budget overruns. Stakeholders are looking for ways to improve program management and the decision making process given the very fluid and uncertain economic and political environment. Consequently, they have increasingly resorted to risk management as the main management tool for achieving defense programs objectives and for delivering the defense capabilities strongly needed for the soldiers on the ground on time and within limited defense budgets. Following a risk management based decision-making approach the stakeholders are expected not only to protect program objectives against a wide range of risks but, at the same time, to take advantage of the opportunities to increase the likelihood of program success. The prerequisite for making risk management the main tool for achieving defense programs objectives is the design and implementation of a strong risk management framework as a foundation providing an efficient and effective application of the best risk management practices. The aim of this paper is to examine the risk management framework for defense programs based on the ISO 31000:2009 standard, best risk management practices and the defense programs’ needs and particularities. For the purposes of this article, the term of defense programs refers to joint defense programs.

  17. Control Processes and Defense Mechanisms

    OpenAIRE

    HOROWITZ, MARDI; Cooper, Steven; FRIDHANDLER, BRAM; Perry, J. Christopher; Bond, Michael; VAILLANT, GEORGE

    1992-01-01

    Defense-mechanism theory and control-process theory are related psychodynamic approaches to explaining and classifying how people ward off emotional upsets. Although both theories explain defensive maneuvers in the same motivational terms, each defines categories different1y. Classic categories define defense mechanisms at a relatively macroscopic level, whereas control-process theory aims at relatively microgenetic analysis of how cognitive maneuvers—involving what is th...

  18. Plant Defense against Insect Herbivores

    OpenAIRE

    Søren Bak; Joel Fürstenberg-Hägg; Mika Zagrobelny

    2013-01-01

    Plants have been interacting with insects for several hundred million years, leading to complex defense approaches against various insect feeding strategies. Some defenses are constitutive while others are induced, although the insecticidal defense compound or protein classes are often similar. Insect herbivory induce several internal signals from the wounded tissues, including calcium ion fluxes, phosphorylation cascades and systemic- and jasmonate signaling. These are perceived in undamaged...

  19. Commentary—Defensive Marketing Strategies

    OpenAIRE

    John R. Hauser; Steven M. Shugan

    2008-01-01

    For every new product and service entrant, there are usually many incumbents who must defend their positions in the market. Hence, defensive strategy is as least as critical as new-product strategy. Our 1983 article argued that defensive strategy critically depends on the distribution of buyer preferences and the position of the new entrant relative to the position of the incumbent in a multidimensional attribute space. Since the appearance of our 1983 article in , research in defensive strat...

  20. Teaching Psychological Defense Mechanisms: "The Defense Mechanisms Game."

    Science.gov (United States)

    Waugh, Charles G.

    1980-01-01

    Presents the rules for an educational game in which students reinforce psychology lecture material by creating and dramatizing defense mechanisms such as reaction formation, displacement, and fantasy. Provides definitions and examples of the various defense mechanisms that can be portrayed. (JP)

  1. Antibacterial Resistance in African Catfish Aquaculture: a Review

    OpenAIRE

    Madubuike U. ANYANWU; Chah, Kennedy F.

    2016-01-01

    Antibacterial resistance (AR) is currently one of the greatest threats to mankind as it constitutes health crisis. Extensive use of antibacterial agents in human and veterinary medicine, and farm crops have resulted in emergence of antibacterial-resistant organisms in different environmental settings including aquaculture. Antibacterial resistance in aquaculture is a serious global concern because antibacterial resistance genes (ARGs) can be transferred easily from aquaculture setting to othe...

  2. Induction, selection and antibacterial activity of the antibacterial peptides from lepldopteran insect cultured cell lines

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    We induced 3 cell lines that were in vitro cultured from Lepidoptera with heat inactivated Escherichia coil DH5α to stimulate the antibacterial peptide followed by antibacterial activity assay,induction dynamic research and Tricine sodium dodecyl sulfate-polyacrylamide gel electrophoresis (Tricine SDS-PAGE) experiment.The antibacterial activity of the induced BTI-Tn-5B1 cell line was the highest,and the antibacterial activity increased gradually to the highest level in 16 hours after stimulation.A new antibacterial peptide with a molecular weight of about 8000 Da was preferentially induced in Trichoplusia ni BTI-Tn-5B1 ceils in 16 hours after stimulation.Antibacterial activity assays indicated that it had inhibition against Staphylococcus aureus,Escherichia coli K12D31 and Salmonella derby.It has especially strong inhibition against Gram-negative bacteria such as Escherichia coli KI2D31 and Salmonella derby.

  3. Recurrent Gene Duplication Diversifies Genome Defense Repertoire in Drosophila.

    Science.gov (United States)

    Levine, Mia T; Vander Wende, Helen M; Hsieh, Emily; Baker, EmilyClare P; Malik, Harmit S

    2016-07-01

    Transposable elements (TEs) comprise large fractions of many eukaryotic genomes and imperil host genome integrity. The host genome combats these challenges by encoding proteins that silence TE activity. Both the introduction of new TEs via horizontal transfer and TE sequence evolution requires constant innovation of host-encoded TE silencing machinery to keep pace with TEs. One form of host innovation is the adaptation of existing, single-copy host genes. Indeed, host suppressors of TE replication often harbor signatures of positive selection. Such signatures are especially evident in genes encoding the piwi-interacting-RNA pathway of gene silencing, for example, the female germline-restricted TE silencer, HP1D/Rhino Host genomes can also innovate via gene duplication and divergence. However, the importance of gene family expansions, contractions, and gene turnover to host genome defense has been largely unexplored. Here, we functionally characterize Oxpecker, a young, tandem duplicate gene of HP1D/rhino We demonstrate that Oxpecker supports female fertility in Drosophila melanogaster and silences several TE families that are incompletely silenced by HP1D/Rhino in the female germline. We further show that, like Oxpecker, at least ten additional, structurally diverse, HP1D/rhino-derived daughter and "granddaughter" genes emerged during a short 15-million year period of Drosophila evolution. These young paralogs are transcribed primarily in germline tissues, where the genetic conflict between host genomes and TEs plays out. Our findings suggest that gene family expansion is an underappreciated yet potent evolutionary mechanism of genome defense diversification. PMID:26979388

  4. Antibacterial phenylpropanoid glycosides from Paulownia tomentosa Steud.

    Science.gov (United States)

    Kang, K H; Jang, S K; Kim, B K; Park, M K

    1994-12-01

    The butanol extract of Paulownia tomentosa stem showed antibacterial activity against Staphylococcus aureus (SG511, 285 and 503), Streptococcus pyogenes (A308 and A77) and Streptococcus faecium MD8b etc. The most active compound of the extract was identified to be campneoside I, which had a minimal inhibitory concentration (MIC) of 150 micrograms/ml against Streptococcus and Staphylococcus species. From such antibacterial activity, the methoxy group of campneoside I was postulated to be the essential element for the antibacterial activity. PMID:10319161

  5. Construction of a Metagenomic DNA Library of Sponge Symbionts and Screening of Antibacterial Metabolites

    Institute of Scientific and Technical Information of China (English)

    CHEN Juan; ZHU Tianjiao; LI Dehai; CUI Chengbin; FANG Yuchun; LIU Hongbing; LIU Peipei; GU Qianqun; ZHU Weiming

    2006-01-01

    To study the bioactive metabolites produced by sponge-derived uncultured symbionts, a metagenomic DNA library of the symbionts of sponge Gelliodes gracilis was constructed. The average size of DNA inserts in the library was 20 kb. This library was screened for antibiotic activity using paper disc assaying. Two clones displayed the antibacterial activity against Micrococcus tetragenus. The metabolites of these two clones were analyzed through HPLC. The result showed that their metabolites were quite different from those of the host E. coli DH5α and the host containing vector pHZ132. This study may present a new approach to exploring bioactive metabolites of sponge symbionts.

  6. Assertion and Defense Mechanism Preference.

    Science.gov (United States)

    Massong, Stefan R.; And Others

    1982-01-01

    Investigated whether assertive and nonassertive individuals differ in defense mechanisms they most typically rely on when confronted with interpersonal stress and conflict. Results indicated assertive males and females both endorsed the most adaptive defense mechanism cluster, whereas nonassertive males and females endorsed more primitive defense…

  7. Recent advances in understanding the antibacterial properties of flavonoids.

    Science.gov (United States)

    Cushnie, T P Tim; Lamb, Andrew J

    2011-08-01

    Antibiotic resistance is a major global problem and there is a pressing need to develop new therapeutic agents. Flavonoids are a family of plant-derived compounds with potentially exploitable activities, including direct antibacterial activity, synergism with antibiotics, and suppression of bacterial virulence. In this review, recent advances towards understanding these properties are described. Information is presented on the ten most potently antibacterial flavonoids as well as the five most synergistic flavonoid-antibiotic combinations tested in the last 6 years (identified from PubMed and ScienceDirect). Top of these respective lists are panduratin A, with minimum inhibitory concentrations (MICs) of 0.06-2.0 μg/mL against Staphylococcus aureus, and epicatechin gallate, which reduces oxacillin MICs as much as 512-fold. Research seeking to improve such activity and understand structure-activity relationships is discussed. Proposed mechanisms of action are also discussed. In addition to direct and synergistic activities, flavonoids inhibit a number of bacterial virulence factors, including quorum-sensing signal receptors, enzymes and toxins. Evidence of these molecular effects at the cellular level include in vitro inhibition of biofilm formation, inhibition of bacterial attachment to host ligands, and neutralisation of toxicity towards cultured human cells. In vivo evidence of disruption of bacterial pathogenesis includes demonstrated efficacy against Helicobacter pylori infection and S. aureus α-toxin intoxication. PMID:21514796

  8. Optical control of antibacterial activity

    Science.gov (United States)

    Velema, Willem A.; van der Berg, Jan Pieter; Hansen, Mickel J.; Szymanski, Wiktor; Driessen, Arnold J. M.; Feringa, Ben L.

    2013-11-01

    Bacterial resistance is a major problem in the modern world, stemming in part from the build-up of antibiotics in the environment. Novel molecular approaches that enable an externally triggered increase in antibiotic activity with high spatiotemporal resolution and auto-inactivation are highly desirable. Here we report a responsive, broad-spectrum, antibacterial agent that can be temporally activated with light, whereupon it auto-inactivates on the scale of hours. The use of such a ‘smart’ antibiotic might prevent the build-up of active antimicrobial material in the environment. Reversible optical control over active drug concentration enables us to obtain pharmacodynamic information. Precisely localized control of activity is achieved, allowing the growth of bacteria to be confined to defined patterns, which has potential for the development of treatments that avoid interference with the endogenous microbial population in other parts of the organism.

  9. Antibacterial activity of Parmelia perlata

    Institute of Scientific and Technical Information of China (English)

    Alwar Vidyalakshmi; Kandaswamy Kruthika

    2012-01-01

    Objective: To test efficacy of Parmelia perlata (P. perlata), which is used in traditional medicine for rapid wound healing against test bacteria that cause wound infections. Methods: Different solvents such as methanol, ethyl acetate and acetone were used for extraction of P. perlata. The sensitivity of the test bacteria to solvent extracts of P. perlata was tested by measuring the zone of inhibition on growth media and by determining the minimal inhibitory concentration and minimal bactericidal concentration. Results: Methanol, ethyl acetate and acetone extracts of P.perlata have shown inhibitory activity against Staphylococcus aureus (S.aureus). Conclusions: The results of the present study indicate that P. perlata has potential antibacterial compounds againstS.aureus that causes multitude of skin infections among human beings. Development of drugs from natural compounds can help us to combat antibiotic-resistant bacteria.

  10. Dendritic nanocomposite for delivery of antibacterial agent

    Institute of Scientific and Technical Information of China (English)

    Pureti Madhu Kumar; PSrinivasa Babu; Shaik Rasheed; Ramadoss Karthikeyan

    2013-01-01

    Objective: To develop and explore the use of PEGylated poly (propylene imine) dendritic architecture for the delivery of an anti bacterial bioactive, Trimethoprim. Methods: For this study, PEGylated poly(propylene imine) dendritic architecture was synthesized and loaded with Trimethoprim and targeted to the resistant producing strains of both gram positive and gram negative. The antibacterial activity was carried out by agar well-diffusion method to compare zone of inhibition with standard drug and plain PPI dendrimer. Results: The study showed that the Trimethoprim loaded dendrimer has significant antibacterial activity than the plain PPI dendrimer, but standard drug was not shown zone of inhibition upon both microorganisms butKlebsiella pneumoniae (K. pneumoniae) the pure drug showed activity. Conclusions: In this study antibacterial activity of synthesized system is also relatively safer and holds potential to deliver any other antibacterial agent to the resistant producing strains.

  11. Technical Soddi Defenses: The Trojan Horse Defense Revisited

    OpenAIRE

    Chad Steel

    2014-01-01

    In 2004, the Trojan horse defense was at a crossroads, with two child pornography cases where it was successfully employed in the United Kingdom, resulting in acquittals.  The original Trojan horse defense has now become part of the more general “technical SODDI” defense, which includes the possibility of unknown actors using unsecured Wi-Fi connections or having physical access to a computer to perform criminal acts.  In the past ten years, it has failed to be effective in the United States ...

  12. Antibacterial activity of polyphenols of Garcinia indica

    OpenAIRE

    Lakshmi, C.; K Akshaya Kumar; T J Dennis; T. S. S. P. N. S. Sanath Kumar

    2011-01-01

    The aim of present work is to study the antibacterial activity of polyphenols isolated from the ethyl acetate soluble of methanol extract of stem bark of Garcinia indica against Staphylococcus aureus, Salmonella typhi and Escherichia coli by paper disc method. The results showed good antibacterial activity against S. aureus at higher concentrations, moderate at lower concentrations, against S. typhi moderate at higher concentrations but no activity against E. coli even at higher concentration...

  13. Antibacterial Activity of Polyphenols of Garcinia Indica

    OpenAIRE

    Lakshmi, C.; Kumar, K. Akshaya; T J Dennis; Kumar, T. S. S. P. N. S. Sanath

    2011-01-01

    The aim of present work is to study the antibacterial activity of polyphenols isolated from the ethyl acetate soluble of methanol extract of stem bark of Garcinia indica against Staphylococcus aureus, Salmonella typhi and Escherichia coli by paper disc method. The results showed good antibacterial activity against S. aureus at higher concentrations, moderate at lower concentrations, against S. typhi moderate at higher concentrations but no activity against E. coli even at higher concentration...

  14. Antibacterial Effect of Human Amnion Membrane

    OpenAIRE

    Kashani, L. (MD; Okhly, M. (BSc); Ghaemi, EA. (PhD); N. Behnampour; Kashani, E. (MD; Okhly, HO. (BSc); Fendereski, S. (BSc); Bazoori, M. (BSc; Falsafi, L. (MSc)

    2015-01-01

    Background and Objective: Along with antibiotics, the use of biological methods to combat bacteria is notably considered. A natural barrier such as amniotic membrane is one of the ways of dealing with bacterial infections. The aim of this study was to determine the antibacterial effect of human amniotic membrane. Materials and Methods: This descriptive study was performed in Dezyani teaching Hospital of Gorgan University of Medical Sciences, Iran. To evaluate the antibacterial activity agains...

  15. Antibacterial activity of mushroom Osmoporus odoratus

    Directory of Open Access Journals (Sweden)

    Sivakumar R

    2006-01-01

    Full Text Available The petroleum ether, chloroform, acetone and water extracts of mushroom Osmoporus odoratus were selected for examine the antibacterial activity against Staphylococcus aureus, Streptococcus pyogenes, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa by disc diffusion method using Muller Hinton agar media. And the extracts were compared with that of standard ampicillin (30 µg and chloramphenicol (30 µg. The water extract alone showed antibacterial activity against the tested organisms and the results were comparable with that of ampicillin rather than chloramphenicol.

  16. Copper-polymer nanocomposites: An excellent and cost-effective biocide for use on antibacterial surfaces.

    Science.gov (United States)

    Tamayo, Laura; Azócar, Manuel; Kogan, Marcelo; Riveros, Ana; Páez, Maritza

    2016-12-01

    The development of polymer nanocomposites with antimicrobial properties has been a key factor for controlling or inhibiting the growth of microorganisms and preventing foodborne diseases and nosocomial infections. Commercially available antibacterial products based on silver-polymer are the most widely used despite the fact that copper is considerably less expensive. The incorporation of copper nanoparticles as antibacterial agents in polymeric matrices to generate copper-polymer nanocomposites have presented excellent results in inhibiting the growth of a broad spectrum of microorganisms. The potential applications in food packaging, medical devices, textiles and pharmaceuticals and water treatment have generated an increasing number of investigations on preparing copper based nanocomposites and alternative polymeric matrices, as potential hosts of nano-modifiers. This review presents a comprehensive compilation of previous published work on the subject, mainly related to the antimicrobial activity of copper polymer nanocomposites. Within all the phenomenology associated to antibacterial effects we highlight the possible mechanisms of action. We discuss the differences in the susceptibility of Gram negative and positive bacteria to the antibacterial activity of nanocomposites, and influencing factors. As well, the main applications of copper polymer-metal nanocomposites are described, considering their physical and chemical characteristics. Finally, some commercially available copper-polymer nanocomposites are described. PMID:27612841

  17. Arabidopsis defense response against Fusarium oxysporum.

    Science.gov (United States)

    Berrocal-Lobo, Marta; Molina, Antonio

    2008-03-01

    The plant fungal pathogen Fusarium oxysporum (Fox) is the causal agent of root rot or wilt diseases in several plant species, including crops such as tomato (Solanum lycopersicum), banana (Musa sapientum) and asparagus (Asparagus officinalis). Colonization of plants by Fox leads to the necrosis of the infected tissues, a subsequent collapse of vascular vessels and decay of the plant. Plant resistance to Fox appears to be monogenic or oligogenic depending on the host. Perception of Fox by plants follows the concept of elicitor-induced immune response, which in turn activates several plant defense signaling pathways. Here, we review the Fox-derived elicitors identified so far and the interaction among the different signaling pathways mediating plant resistance to Fox. PMID:18289920

  18. Strengthening MT6D Defenses with Darknet and Honeypot capabilities

    OpenAIRE

    Basam, Dileep Kumar

    2015-01-01

    With the ever increasing adoption of IPv6, there has been a growing concern for security and privacy of IPv6 networks. Mechanisms like the Moving Target IPv6 Defense (MT6D) leverage the immense address space available with the new 128-bit addressing scheme to improve security and privacy of IPv6 networks. MT6D allows participating hosts to hop onto new addresses, that are cryptographically computed, without any disruption to ongoing conversations. However, there is no feedback mechani...

  19. Defense Strategies Against Modern Botnets

    CERN Document Server

    Stankovic, Srdjan

    2009-01-01

    Botnets are networks of compromised computers with malicious code which are remotely controlled and which are used for starting distributed denial of service (DDoS) attacks, sending enormous number of e-mails (SPAM) and other sorts of attacks. Defense against modern Botnets is a real challenge. This paper offers several strategies for defense against Botnets with a list and description of measures and activities which should be carried out in order to establish successful defense. The paper also offers parallel preview of the strategies with their advantages and disadvantages considered in accordance with various criteria.

  20. Molecular strategies of plant defense and insect counter-defense

    Institute of Scientific and Technical Information of China (English)

    KEYANZHU-SALZMAN; JIAN-LONGBI; TONG-XIANLIU

    2005-01-01

    The prediction of human population growth worldwide indicates there will be a need to substantially increase food production in order to meet the demand on food supply.This can be achieved in part by the effective management of insect pests. Since plants have co-evolved with herbivorous insects for millions of years, they have developed an array of defense genes to protect themselves against a wide variety of chewing and sucking insects.Using these naturally-occurring genes via genetic engineering represents an environmentally friendly insect pest-control measure. Insects, however, have been actively evolving adaptive mechanisms to evade natural plant defenses. Such evolved adaptability undoubtedly has helped insects during the last century to rapidly overcome a great many humanimposed management practices and agents, including chemical insecticides and genetically engineered plants. Thus, better understanding of the molecular and genetic basis of plant defense and insect counter-defense mechanisms is imperative, not only from a basic science perspective, but also for biotechnology-based pest control practice. In this review, we emphasize the recent advance and understanding of molecular strategies of attack-counterattack and defense-counter-defense between plants and their herbivores.

  1. Multiaction antibacterial nanofibrous membranes fabricated by electrospinning: an excellent system for antibacterial applications

    International Nuclear Information System (INIS)

    In this paper, novel multiaction antibacterial nanofibrous membranes containing apatite, Ag, AgBr and TiO2 as four active components were fabricated by an electrospinning technique. In this antibacterial membrane, each component serves a different function: the hydroxyapatite acts as the adsorption material for capturing bacteria, the Ag nanoparticles act as the release-active antibacterial agent, the AgBr nanoparticles act as the visible sensitive and release-active antibacterial agent, and the TiO2 acts as the UV sensitive antibacterial material and substrate for other functional components. Using E. coli as the typical testing organism, such multicomponent membranes exhibit excellent antimicrobial activity under UV light, visible light or in a dark environment. The significant antibacterial properties may be due to the synergetic action of the four major functional components, and the unique porous structure and high surface area of the nanofibrous membrane. It takes only 20 min for the bacteria to be completely (99.9%) destroyed under visible light. Even in a dark environment, about 50 min is enough to kill all of the bacteria. Compared to the four component system in powder form reported previously, the addition of the electrospun membrane could significantly improve the antibacterial inactivation of E. coli under the same evaluation conditions. Besides the superior antimicrobial capability, the permanence of the antibacterial activity of the prepared free-standing membranes was also demonstrated in repeated applications.

  2. Defensive strategies in rugby union.

    Science.gov (United States)

    Hendricks, Sharief; Roode, Brad; Matthews, Bevan; Lambert, Michael

    2013-08-01

    Success in rugby union competition is dependent partly on the defensive strategies of a team. Despite this, little empirical evidence exists about effective defensive strategies used during play. This study attempted to identify defensive characteristics associated with increased likelihood of a successful outcome in rugby union, while considering the game situation. Twenty-one matches of the 2010 Super 14 competition were analysed, amounting to 2,394 coded tackle contacts. The likelihood of the defending team winning the breakdown (the post-tackle contact situation where opposing teams compete for possession of the ball) increased as the match progressed. Defensive speed, measured as the speed of the defence in response to the attacking line, was a statistically significant predictor of breakdown wins and preventing the attacking team from advancing towards the gain line. Identifying the relative effectiveness of such strategies allows understanding of rugby match behaviour and may be applied to improve organisation, design, training, teaching and learning the game. PMID:24422340

  3. Defense Meteorological Satellite Program (DMSP)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Defense Meteorological Satellite Program (DMSP) satellites collect visible and infrared cloud imagery as well as monitoring the atmospheric, oceanographic,...

  4. Antimicrobial defense of the earthworm

    Czech Academy of Sciences Publication Activity Database

    Bilej, Martin; De Baetselier, P.; Beschin, A.

    2000-01-01

    Roč. 45, č. 4 (2000), s. 283-300. ISSN 0015-5632 R&D Projects: GA ČR GA310/99/1385; GA ČR GA310/00/1372 Institutional research plan: CEZ:AV0Z5020903 Keywords : cellular defense mechanisms * humoral defense mechanisms Subject RIV: EE - Microbiology, Virology Impact factor: 0.752, year: 2000

  5. Prulifloxacin: a new antibacterial fluoroquinolone.

    Science.gov (United States)

    Prats, Guillem; Rossi, Vilma; Salvatori, Enrica; Mirelis, Beatriz

    2006-02-01

    In the last few years, the antimicrobial activity, efficacy and relative safety of fluoroquinolones have made them attractive for the treatment of community-acquired and nosocomial infections. Prulifloxacin is a new fluoroquinolone antibacterial agent with a broad spectrum of activity against Gram-positive and -negative bacteria. Prulifloxacin is available for oral use, and after absorption is metabolized in to the active form, ulifloxacin. It exhibits good penetration in target tissues and a long elimination half-life, allowing once-daily administration. A number of randomized, controlled clinical trials carried out in Europe demonstrated the efficacy of prulifloxacin in the treatment of urinary tract (acute uncomplicated and complicated) and respiratory tract infections (acute exacerbations of chronic bronchitis), in comparison with the most widely used drugs such as ciprofloxacin, co-amoxiclav and pefloxacin. Prulifloxacin was generally well tolerated. The most frequent adverse reactions observed in clinical trials were gastric pain, diarrhea, nausea and skin rash. This review focuses on the characteristics of prulifloxacin, summarizing the relevant preclinical and clinical data. PMID:16441207

  6. Modulation of pulmonary defense mechanisms by acute exposures to nitrogen dioxide. [Staphylococcus aureus; Proteus mirabilis; Pasteurella pneumotropica

    Energy Technology Data Exchange (ETDEWEB)

    Jakab, G.J.

    1987-02-01

    The effect of acute exposures to NO/sub 2/ on the antibacterial defenses of the murine lung was assessed following inhalation challenges with Staphylococcus aureus, Proteus mirabilis, and Pasteurella pneumotropica. With S. aureus pulmonary antibacterial defenses were suppressed at NO/sub 2/ levels of 4.0 ppm and greater. Exposure to 10.0 ppm enhanced the intrapulmonary killing of P. mirabilis which correlated with an increase in the phagocytic cell populations lavaged from the lungs; at 20.0 ppm bactericidal activity against P. mirabilis was impaired. Pulmonary antibacterial defenses against P. pneumotropica were impaired at 10.0 ppm which correlated with a decrease in the retrieved phagocytic lung cell population. Reversing the order of treatment (ie., NO/sub 2/ exposure prior to bacterial challenge) raised the threshold concentration for NO/sub 2/-induced impairment of intrapulmonary bacterial killing. With S. aureus the effect was not observed at 5.0 ppm but at 10.0 ppm and with P. mirabilis not at 20.0 ppm but at 30.0 ppm intrapulmonary killing was enhanced. Exposures up to 20.0 ppm of NO/sub 2/ did not effect the physical translocation mechanisms of the lung as quantitated by declines in pulmonary radiotracer activity following aerogenic challenge with /sup 32/P-labeled staphylococci.

  7. Proteomic Characterization of Host Response to Yersinia pestis

    Energy Technology Data Exchange (ETDEWEB)

    Chromy, B; Perkins, J; Heidbrink, J; Gonzales, A; Murhpy, G; Fitch, J P; McCutchen-Maloney, S

    2004-05-11

    Host-pathogen interactions result in protein expression changes within both the host and the pathogen. Here, results from proteomic characterization of host response following exposure to Yersinia pestis, the causative agent of plague, and to two near neighbors, Y. pseudotuberculosis and Y. enterocolitica, are reported. Human monocyte-like cells were chosen as a model for macrophage immune response to pathogen exposure. Two-dimensional electrophoresis followed by mass spectrometry was used to identify host proteins with differential expression following exposure to these three closely related Yersinia species. This comparative proteomic characterization of host response clearly shows that host protein expression patterns are distinct for the different pathogen exposures, and contributes to further understanding of Y. pestis virulence and host defense mechanisms. This work also lays the foundation for future studies aimed at defining biomarkers for presymptomatic detection of plague.

  8. Sustained Release of Antibacterial Lipopeptides from Biodegradable Polymers against Oral Pathogens.

    Science.gov (United States)

    Eckhard, Lea H; Houri-Haddad, Yael; Sol, Asaf; Zeharia, Rotem; Shai, Yechiel; Beyth, Shaul; Domb, Abraham J; Bachrach, Gilad; Beyth, Nurit

    2016-01-01

    The development of antibacterial drugs to overcome various pathogenic species, which inhabit the oral cavity, faces several challenges, such as salivary flow and enzymatic activity that restrict dosage retention. Owing to their amphipathic nature, antimicrobial peptides (AMPs) serve as the first line of defense of the innate immune system. The ability to synthesize different types of AMPs enables exploitation of their advantages as alternatives to antibiotics. Sustained release of AMPs incorporated in biodegradable polymers can be advantageous in maintaining high levels of the peptides. In this study, four potent ultra-short lipopeptides, conjugated to an aliphatic acid chain (16C) were incorporated in two different biodegradable polymers: poly (lactic acid co castor oil) (PLACO) and ricinoleic acid-based poly (ester-anhydride) (P(SA-RA)) for sustained release. The lipopeptide and polymer formulations were tested for antibacterial activity during one week, by turbidometric measurements of bacterial outgrowth, anti-biofilm activity by live/dead staining, biocompatibility by hemolysis and XTT colorimetric assays, mode of action by fluorescence-activated cell sorting (FACS) and release profile by a fluorometric assay. The results show that an antibacterial and anti-biofilm effect, as well as membrane disruption, can be achieved by the use of a formulation of lipopeptide incorporated in biodegradable polymer. PMID:27606830

  9. Technical Soddi Defenses: The Trojan Horse Defense Revisited

    Directory of Open Access Journals (Sweden)

    Chad Steel

    2014-12-01

    Full Text Available In 2004, the Trojan horse defense was at a crossroads, with two child pornography cases where it was successfully employed in the United Kingdom, resulting in acquittals.  The original Trojan horse defense has now become part of the more general “technical SODDI” defense, which includes the possibility of unknown actors using unsecured Wi-Fi connections or having physical access to a computer to perform criminal acts.  In the past ten years, it has failed to be effective in the United States for criminal cases, with no published acquittals in cases where it was the primary defense.  In the criminal cases where it has been used as leverage in plea negotiations, there has been either poor forensics performed by the prosecution or political pressure to resolve a matter.  On the civil side, however, the defense has been wildly successful, effectively shutting down large John Doe copyright infringement litigation against non-commercial violators.  

  10. Seaweed Polysaccharides and Derived Oligosaccharides Stimulate Defense Responses and Protection Against Pathogens in Plants

    Directory of Open Access Journals (Sweden)

    Alejandra Moenne

    2011-11-01

    Full Text Available Plants interact with the environment by sensing “non-self” molecules called elicitors derived from pathogens or other sources. These molecules bind to specific receptors located in the plasma membrane and trigger defense responses leading to protection against pathogens. In particular, it has been shown that cell wall and storage polysaccharides from green, brown and red seaweeds (marine macroalgae corresponding to ulvans, alginates, fucans, laminarin and carrageenans can trigger defense responses in plants enhancing protection against pathogens. In addition, oligosaccharides obtained by depolymerization of seaweed polysaccharides also induce protection against viral, fungal and bacterial infections in plants. In particular, most seaweed polysaccharides and derived oligosaccharides trigger an initial oxidative burst at local level and the activation of salicylic (SA, jasmonic acid (JA and/or ethylene signaling pathways at systemic level. The activation of these signaling pathways leads to an increased expression of genes encoding: (i Pathogenesis-Related (PR proteins with antifungal and antibacterial activities; (ii defense enzymes such as pheylalanine ammonia lyase (PAL and lipoxygenase (LOX which determine accumulation of phenylpropanoid compounds (PPCs and oxylipins with antiviral, antifugal and antibacterial activities and iii enzymes involved in synthesis of terpenes, terpenoids and/or alkaloids having antimicrobial activities. Thus, seaweed polysaccharides and their derived oligosaccharides induced the accumulation of proteins and compounds with antimicrobial activities that determine, at least in part, the enhanced protection against pathogens in plants.

  11. Tunable, antibacterial activity of silicone polyether surfactants.

    Science.gov (United States)

    Khan, Madiha F; Zepeda-Velazquez, Laura; Brook, Michael A

    2015-08-01

    Silicone surfactants are used in a variety of applications, however, limited data is available on the relationship between surfactant structure and biological activity. A series of seven nonionic, silicone polyether surfactants with known structures was tested for in vitro antibacterial activity against Escherichia coli BL21. The compounds varied in their hydrophobic head, comprised of branched silicone structures with 3-10 siloxane linkages and, in two cases, phenyl substitution, and hydrophilic tail of 8-44 poly(ethylene glycol) units. The surfactants were tested at three concentrations: below, at, and above their Critical Micelle Concentrations (CMC) against 5 concentrations of E. coli BL21 in a three-step assay comprised of a 14-24h turbidometric screen, a live-dead stain and viable colony counts. The bacterial concentration had little effect on antibacterial activity. For most of the surfactants, antibacterial activity was higher at concentrations above the CMC. Surfactants with smaller silicone head groups had as much as 4 times the bioactivity of surfactants with larger groups, with the smallest hydrophobe exhibiting potency equivalent to sodium dodecyl sulfate (SDS). Smaller PEG chains were similarly associated with higher potency. These data link lower micelle stability and enhanced permeability of smaller silicone head groups to antibacterial activity. The results demonstrate that simple manipulation of nonionic silicone polyether structure leads to significant changes in antibacterial activity. PMID:26057244

  12. Antibacterial Effect of Human Amnion Membrane

    Directory of Open Access Journals (Sweden)

    Kashani, L. (MD

    2015-01-01

    Full Text Available Background and Objective: Along with antibiotics, the use of biological methods to combat bacteria is notably considered. A natural barrier such as amniotic membrane is one of the ways of dealing with bacterial infections. The aim of this study was to determine the antibacterial effect of human amniotic membrane. Materials and Methods: This descriptive study was performed in Dezyani teaching Hospital of Gorgan University of Medical Sciences, Iran. To evaluate the antibacterial activity against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli bacteria, 20 amniotic membranes were obtained from postpartum mothers and examined by repeated dilution, diffusion and extraction techniques. Data were collected by observation method and described by mean and standard deviation. Results: The antibacterial activity was found in 15% of the samples against Staphylococcus Aureus and Pseudomonas aeruginosa, while no antibacterial activity was found against E. coli. Given the 15% positive responses, "Diffusion" and "repeated dilution" techniques were more effective in investigating the antibacterial effect of amniotic membrane. Conclusion: The results show the probability of antimicrobial effect of amniotic membrane tissue and it seems that this property can be affected by many factors.

  13. Antibacterial resistance: Current problems and possible solutions

    Directory of Open Access Journals (Sweden)

    Sharma Rashmi

    2005-03-01

    Full Text Available Antimicrobial resistance is a natural biological phenomenon of response of microbes to the selective pressure of an antimicrobial drug. Resistance may be inherent, which explains the phenomenon of opportunistic infection or acquired. Concern about the resistance increased in the late 1990′s and since then, many governmental and agency reports have been published regarding the agricultural use of antibacterials, advising less use of antibacterials, appropriate choice of antibacterials and regimens, prevention of cross-infection and development of new antibacterials. The emergence of multidrug resistant strains of Gram-negative bacteria (Pseudomonas, Klebsiella, Enterobacter, Acinetobacter, Salmonella species and Gram-positve organisms (Staphylococcus, Enterococcus, Streptococcus species is the more worrisome in the present therapeutic scenario. Multidrug - resistant tuberculosis is another serious public health problems. Resistance to some agents can be overcome by modifying the dosage regimens (e.g., using high-dose therapy or inhibiting the resistance mechanism (e.g., beta-lactamase inhibitors, whereas other mechanisms of resistance can only be overcome by using an agent from a different class. It is urgently required to ban the sale of antibiotics without prescription, to use antibiotics more judiciously in hospitals by intensive teaching of the principles of the use of antibiotics and to establish better control measures for nosocomial infections. Thus, it is highly recommended that practicing physicians should become aware of the magnitude of existing problem of antibacterial resistance and help in fighting this deadly threat by rational prescribing.

  14. Toxicity and antibacterial assessment of chitosan-coated silver nanoparticles on human pathogens and macrophage cells

    Directory of Open Access Journals (Sweden)

    Jena P

    2012-04-01

    Full Text Available Prajna Jena1, Soumitra Mohanty1, Rojee Mallick1, Biju Jacob2, Avinash Sonawane11School of Biotechnology, KIIT University, Bhubaneswar, Orissa, India; 2Center for Innovation, Technopark Technology Business Incubator, Bangalore, Karnataka, IndiaBackground: Pathogenic bacteria are able to develop various strategies to counteract the bactericidal action of antibiotics. Silver nanoparticles (AgNPs have emerged as a potential alternative to conventional antibiotics because of their potent antimicrobial properties. The purpose of this study was to synthesize chitosan-stabilized AgNPs (CS-AgNPs and test for their cytotoxic, genotoxic, macrophage cell uptake, antibacterial, and antibiofilm activities.Methods: AgNPs were synthesized using chitosan as both a stabilizing and a reducing agent. Antibacterial activity was determined by colony-forming unit assay and scanning electron microscopy. Genotoxic and cytotoxic activity were determined by DNA fragmentation, comet, and MTT [3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide] assays. Cellular uptake and intracellular antibacterial activity were tested on macrophages.Results: CS-AgNPs exhibited potent antibacterial activity against different human pathogens and also impeded bacterial biofilm formation. Scanning electron microscopy analysis indicated that CS-AgNPs kill bacteria by disrupting the cell membrane. CS-AgNPs showed no significant cytotoxic or DNA damage effect on macrophages at the bactericidal dose. Propidium iodide staining indicated active endocytosis of CS-AgNPs resulting in reduced intracellular bacterial survival in macrophages.Conclusion: The present study concludes that at a specific dose, chitosan-based AgNPs kill bacteria without harming the host cells, thus representing a potential template for the design of antibacterial agents to decrease bacterial colonization and to overcome the problem of drug resistance.Keywords: chitosan-silver nanoparticles, antibiofilm, cytotoxicity

  15. INSURMOUNTABLE HEAT: THE EVOLUTION AND PERSISTENCE OF DEFENSIVE HYPERTHERMIA.

    Science.gov (United States)

    Clint, Edward; Fessler, Daniel M T

    2016-03-01

    Fever, the rise in body temperature set point in response to infection or injury, is a highly conserved trait among vertebrates, and documented in many arthropods. Fever is known to reduce illness duration and mortality. These observations present an evolutionary puzzle: why has fever continued to be an effective response to fast-evolving pathogenic microbes across diverse phyla, and probably over countless millions of years? Framing fever as part of a more general thermal manipulation strategy that we term defensive hyperthermia, we hypothesize that the solution lies in the independent contributions to pathogen fitness played by virulence and infectivity. A host organism deploying defensive hyperthermia alters the ecological environment of an invading pathogen. To the extent that the pathogen evolves to be able to function effectively at elevated temperatures, it disadvantages itself at infecting the next (thermonormative) host, becoming more likely to be thwarted by that host's immune system and outcompeted by wild ecotype conspecifics (a genetically distinct strain adapted to specific environmental conditions) that, although more vulnerable to elevated temperatures, operate more effectively at the host's normal temperature. We evaluate this hypothesis in light of existing evidence concerning pathogen thermal specialization, and discuss theoretical and translational implications of this model. PMID:27192778

  16. MgO nanoparticles as antibacterial agent: preparation and activity

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Zhen-Xing, E-mail: tangzhenxing@126.com [Department of Food Science, Anqing, Vocational and Technical College, Anqing, Anhui (China); Lv, Bin-Feng [Date Palm Research Center, King Faisal University, (Saudi Arabia)

    2014-07-15

    Bacterial pollution is a great risk for human health. Nanotechnology offers a way to develop new inorganic antibacterial agents. Nano-inorganic metal oxide has a potential to reduce bacterial contamination. MgO is an important inorganic oxide and has been widely used in many fields. Many studies have shown that MgO nanoparticles have good antibacterial activity. Therefore, in this paper, the main synthesis methods, antibacterial activity and antibacterial mechanisms of MgO nanoparticles are reviewed. (author)

  17. MgO nanoparticles as antibacterial agent: preparation and activity

    Directory of Open Access Journals (Sweden)

    Zhen-Xing Tang

    2014-09-01

    Full Text Available Bacterial pollution is a great risk for human health. Nanotechnology offers a way to develop new inorganic antibacterial agents. Nano-inorganic metal oxide has a potential to reduce bacterial contamination. MgO is an important inorganic oxide and has been widely used in many fields. Many studies have shown that MgO nanoparticles have good antibacterial activity. Therefore, in this paper, the main synthesis methods, antibacterial activity and antibacterial mechanisms of MgO nanoparticles are reviewed.

  18. The pathogen-actin connection: A platform for defense signaling in plants

    Energy Technology Data Exchange (ETDEWEB)

    Day, B; Henty, Jessica L; Porter, K J; Staiger, Chris J

    2011-09-08

    The cytoskeleton, a dynamic network of cytoplasmic polymers, plays a central role in numerous fundamental processes, such as development, reproduction, and cellular responses to biotic and abiotic stimuli. As a platform for innate immune responses in mammalian cells, the actin cytoskeleton is a central component in the organization and activation of host defenses, including signaling and cellular repair. In plants, our understanding of the genetic and biochemical responses in both pathogen and host that are required for virulence and resistance has grown enormously. Additional advances in live-cell imaging of cytoskeletal dynamics have markedly altered our view of actin turnover in plants. In this review, we outline current knowledge of host resistance following pathogen perception, both in terms of the genetic interactions that mediate defense signaling, as well as the biochemical and cellular processes that are required for defense signaling.

  19. Regulation of Defense-related Gene Expression during Plant-Pathogen Interactions

    OpenAIRE

    Cramer, C L; Weissenborn, D.; Cottingham, C. K.; Denbow, C. J.; Eisenback, J. D.; Radin, D. N.; Yu, X.

    1993-01-01

    Plants have evolved a broad array of defense mechanisms involved in disease resistance. These include synthesis of phytoalexin antibiotics and proteinase inhibitors, deposition of cell wall materials, and accumulation of hydrolytic enzymes such as chitinases. Resistance appears to depend on the ability of the host to recognize the pathogen rapidly and induce these defense responses in order to limit pathogen spread. Application of molecular technologies has yielded significant new information...

  20. The Role of Hyaluronan in Innate Defense Responses of the Intestine

    OpenAIRE

    de la Motte, Carol A; Sean P Kessler

    2015-01-01

    Hyaluronan is an abundant extracellular matrix component prevalent in the vertebrate intestinal tract. Here we discuss what is known about hyaluronan distribution during homeostasis and inflammatory diseases of the gut and discuss ways in which this glycosaminoglycan can participate in regulating innate host defense mechanisms. These natural responses include mechanisms promoting rapid leukocyte recruitment after bacterial challenge/colon tissue damage as well as promoting epithelial defense ...

  1. Alveolar macrophages and lung surfactant in the defense against Cryptococcus neoformans

    OpenAIRE

    Gross, Norma Teresa

    2000-01-01

    Cryptococcus neoformans causes disease mainly in immunosuppressed patients, especially those with AIDS, and on corticosteroids. The yeast is normally inhaled and the lung is the primary site of infection, where the alveolar macrophages (AM) provide a first line of host defense. The aim of this thesis was to study immune responses of AM and immunomodulatory functions of lung surfactant phospholipids in the defense against C. neoformans, using the rat or rabbit as animal model...

  2. ROS signaling, phytohormone signaling and toxin tolerance: defense mechanisms in Arabidopsis thaliana against Botrytis cinerea

    OpenAIRE

    Cui, Fuqiang

    2014-01-01

    To face the constant challenges from numerous pathogens in the environment, sophisticated defense systems have evolved in plants. Reactive oxygen species (ROS) and phytohormones are important cellular compounds that regulate plant defense systems to overcome biotic stresses from different pathogens. Against biotrophic pathogens, which require living host cells, hypersensitive cell death response (HR), a type of programed cell death mediated by ROS and salicylic acid (SA), is effective for imm...

  3. FACTORS THAT INFLUENCE THE SUPPRESSION OF PULMONARY ANTIBACTERIAL DEFENSES IN MICE EXPOSED TO OZONE

    Science.gov (United States)

    Exposure to ozone (03) has been shown to increase susceptibility of mice to bacterial infection; however the underlying mechanism has not been well elucidated. his study investigated the effect Of 03 exposure on the ability of mice to combat an infectious challenge of Streptococc...

  4. Regulation of antibacterial defense in the small intestine by the nuclear bile acid receptor

    Science.gov (United States)

    Inagaki, Takeshi; Moschetta, Antonio; Lee, Youn-Kyoung; Peng, Li; Zhao, Guixiang; Downes, Michael; Yu, Ruth T.; Shelton, John M.; Richardson, James A.; Repa, Joyce J.; Mangelsdorf, David J.; Kliewer, Steven A.

    2006-03-01

    Obstruction of bile flow results in bacterial proliferation and mucosal injury in the small intestine that can lead to the translocation of bacteria across the epithelial barrier and systemic infection. These adverse effects of biliary obstruction can be inhibited by administration of bile acids. Here we show that the farnesoid X receptor (FXR), a nuclear receptor for bile acids, induces genes involved in enteroprotection and inhibits bacterial overgrowth and mucosal injury in ileum caused by bile duct ligation. Mice lacking FXR have increased ileal levels of bacteria and a compromised epithelial barrier. These findings reveal a central role for FXR in protecting the distal small intestine from bacterial invasion and suggest that FXR agonists may prevent epithelial deterioration and bacterial translocation in patients with impaired bile flow. bacteria | biliary obstruction | epithelial barrier | ileum

  5. Effective antibacterials: at what cost? The economics of antibacterial resistance and its control.

    Science.gov (United States)

    White, Anthony R

    2011-09-01

    The original and successful business model of return on investment being sufficiently attractive to the pharmaceutical industry to encourage development of new antibacterial molecules and related diagnostics has been compromised by increasing development costs and regulatory hurdles, resulting in a decreasing chance of success and financial return. The supply of new effective agents is diminishing along with the number of companies engaged in antibacterial research and development. The BSAC Working Party on The Urgent Need:Regenerating Antibacterial Drug Discovery and Development identified the need to establish, communicate and apply the true health and economic value of antibacterials, along with the adoption of meaningful incentives, as part of the future model for antibacterial development. Robust data are needed on the cost of resistance and ineffective treatment of bacterial infection, along with national and local holistic analyses of the cost-benefit of antibacterials. An understanding of the true health and economic value of antibacterials and the cost of resistance across healthcare systems needs to be generated, communicated and used in order to set a pricing and reimbursement structure that is commensurate with value. The development and economic model of antibacterial use needs to be rebuilt based on this value through dialogue with the various stakeholders, including the pharmaceutical industry, and alternative incentives from 'push' to 'pull' and funding models, such as public/private partnerships, agreed. A research and development model that succeeds in developing and delivering new antibacterial agents that address the health needs of society from start to finish, 'from cradle to grave', must be established. PMID:21700625

  6. A ribosome-inactivating protein in a Drosophila defensive symbiont.

    Science.gov (United States)

    Hamilton, Phineas T; Peng, Fangni; Boulanger, Martin J; Perlman, Steve J

    2016-01-12

    Vertically transmitted symbionts that protect their hosts against parasites and pathogens are well known from insects, yet the underlying mechanisms of symbiont-mediated defense are largely unclear. A striking example of an ecologically important defensive symbiosis involves the woodland fly Drosophila neotestacea, which is protected by the bacterial endosymbiont Spiroplasma when parasitized by the nematode Howardula aoronymphium. The benefit of this defense strategy has led to the rapid spread of Spiroplasma throughout the range of D. neotestacea, although the molecular basis for this protection has been unresolved. Here, we show that Spiroplasma encodes a ribosome-inactivating protein (RIP) related to Shiga-like toxins from enterohemorrhagic Escherichia coli and that Howardula ribosomal RNA (rRNA) is depurinated during Spiroplasma-mediated protection of D. neotestacea. First, we show that recombinant Spiroplasma RIP catalyzes depurination of 28S rRNAs in a cell-free assay, as well as Howardula rRNA in vitro at the canonical RIP target site within the α-sarcin/ricin loop (SRL) of 28S rRNA. We then show that Howardula parasites in Spiroplasma-infected flies show a strong signal of rRNA depurination consistent with RIP-dependent modification and large decreases in the proportion of 28S rRNA intact at the α-sarcin/ricin loop. Notably, host 28S rRNA is largely unaffected, suggesting targeted specificity. Collectively, our study identifies a novel RIP in an insect defensive symbiont and suggests an underlying RIP-dependent mechanism in Spiroplasma-mediated defense. PMID:26712000

  7. A Hierarchal System of Defense Mechanisms.

    Science.gov (United States)

    Lee, Gerald

    1979-01-01

    Constructs a hierarchy of defense mechanisms through the addition of the concepts of secondary and tertiary defenses to the already existing psychoanalytic defenses and increases the explanatory power of the concept of defense. Research generated from this theoretical model is presented. (Author/BEF)

  8. Antibacterial Activity of Punica granatum Linn.

    Directory of Open Access Journals (Sweden)

    Kenan Tunç

    2013-08-01

    Full Text Available In this study, it was investigated that the extracts (ethanol, aceton, methanol, ethyl acetat obtained from fruit peels of the plant to whether has antibacterial effect against Streptococcus mitis CNCTC 4/77, Streptococcus salivarius CNCTC 64/59, Streptococcus mutans CNCTC 8/77, Staphylococcus epidermidis ATCC 12228, Staphylococcus aureus ATCC 29213, Escherichia coli ATCC 25922, Salmonella abony NCTC 6017, Salmonella typhimurium ATCC 14028, Enterococcus faecalis ATCC 29212, Bacillus subtilis ATCC 6633 bacteria strains in vitro. The antibacterial activity of extracts was evaluated according to disc diffusion method. It has been determined that pomegranate peel's extract had the highest inhibition zone diameters ( 18-30 mm against S. epidermidis and S. aureus bacteria strains. The antibacterial activity of plant against Streptococcus mitis is determined in this study for the first time.

  9. Trusted Hosts in Host Identity Protocol (HIP)

    OpenAIRE

    K.C., Amir

    2012-01-01

    The goal of the project was to study the possibilities to establish trusted hosts in Host Identity Protocol (HIP) and implement certificate handling in HIP packets. The time complexity and performance while using certificates in HIP packets was also measured. The research project was carried out at Arcada University of Applied Sciences in collaboration with Helsinki University. The project aimed to implement standard x.509 certification of the public key used as HI (Host Identity) to deri...

  10. Ancient host-pathogen associations maintained by specificity of chemotaxis and antibiosis.

    OpenAIRE

    Gerardo, Nicole M.; Jacobs, Sarah R.; Currie, Cameron R; Mueller, Ulrich G.

    2006-01-01

    Switching by parasites to novel hosts has profound effects on ecological and evolutionary disease dynamics. Switching requires that parasites are able to establish contact with novel hosts and to overcome host defenses. For most host–parasite associations, it is unclear as to what specific mechanisms prevent infection of novel hosts. Here, we show that parasitic fungal species in the genus Escovopsis, which attack and consume the fungi cultivated by fungus-growing ants, are attracted to their...

  11. Actinopyga lecanora Hydrolysates as Natural Antibacterial Agents

    Directory of Open Access Journals (Sweden)

    Raheleh Ghanbari

    2012-12-01

    Full Text Available Actinopyga lecanora, a type of sea cucumber commonly known as stone fish with relatively high protein content, was explored as raw material for bioactive peptides production. Six proteolytic enzymes, namely alcalase, papain, pepsin, trypsin, bromelain and flavourzyme were used to hydrolyze A. lecanora at different times and their respective degrees of hydrolysis (DH were calculated. Subsequently, antibacterial activity of the A. lecanora hydrolysates, against some common pathogenic Gram positive bacteria (Bacillus subtilis and Staphylococcus aureus and Gram negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Pseudomonas sp. were evaluated. Papain hydrolysis showed the highest DH value (89.44%, followed by alcalase hydrolysis (83.35%. Bromelain hydrolysate after one and seven hours of hydrolysis exhibited the highest antibacterial activities against Pseudomonas sp., P. aeruginosa and E. coli at 51.85%, 30.07% and 30.45%, respectively compared to the other hydrolysates. Protein hydrolysate generated by papain after 8 h hydrolysis showed maximum antibacterial activity against S. aureus at 20.19%. The potent hydrolysates were further fractionated using RP-HPLC and antibacterial activity of the collected fractions from each hydrolysate were evaluated, wherein among them only three fractions from the bromelain hydrolysates exhibited inhibitory activities against Pseudomonas sp., P. aeruginosa and E. coli at 24%, 25.5% and 27.1%, respectively and one fraction of papain hydrolysate showed antibacterial activity of 33.1% against S. aureus. The evaluation of the relationship between DH and antibacterial activities of papain and bromelain hydrolysates revealed a meaningful correlation of four and six order functions.

  12. Host stress hormones alter vector feeding preferences, success, and productivity.

    Science.gov (United States)

    Gervasi, Stephanie S; Burkett-Cadena, Nathan; Burgan, Sarah C; Schrey, Aaron W; Hassan, Hassan K; Unnasch, Thomas R; Martin, Lynn B

    2016-08-17

    Stress hormones might represent a key link between individual-level infection outcome, population-level parasite transmission, and zoonotic disease risk. Although the effects of stress on immunity are well known, stress hormones could also affect host-vector interactions via modification of host behaviours or vector-feeding patterns and subsequent reproductive success. Here, we experimentally manipulated songbird stress hormones and examined subsequent feeding preferences, feeding success, and productivity of mosquito vectors in addition to defensive behaviours of hosts. Despite being more defensive, birds with elevated stress hormone concentrations were approximately twice as likely to be fed on by mosquitoes compared to control birds. Moreover, stress hormones altered the relationship between the timing of laying and clutch size in blood-fed mosquitoes. Our results suggest that host stress could affect the transmission dynamics of vector-borne parasites via multiple pathways. PMID:27512147

  13. Avoid, attack or do both? Behavioral and physiological adaptations in natural enemies faced with novel hosts

    Directory of Open Access Journals (Sweden)

    Brown Sam P

    2005-11-01

    Full Text Available Abstract Background Confronted with well-defended, novel hosts, should an enemy invest in avoidance of these hosts (behavioral adaptation, neutralization of the defensive innovation (physiological adaptation or both? Although simultaneous investment in both adaptations may first appear to be redundant, several empirical studies have suggested a reinforcement of physiological resistance to host defenses with additional avoidance behaviors. To explain this paradox, we develop a mathematical model describing the joint evolution of behavioral and physiological adaptations on the part of natural enemies to their host defenses. Our specific goals are (i to derive the conditions that may favor the simultaneous investment in avoidance and physiological resistance and (ii to study the factors that govern the relative investment in each adaptation mode. Results Our results show that (i a simultaneous investment may be optimal if the fitness costs of the adaptive traits are accelerating and the probability of encountering defended hosts is low. When (i holds, we find that (ii the more that defended hosts are rare and/or spatially aggregated, the more behavioral adaptation is favored. Conclusion Despite their interference, physiological resistance to host defensive innovations and avoidance of these same defenses are two strategies in which it may be optimal for an enemy to invest in simultaneously. The relative allocation to each strategy greatly depends on host spatial structure. We discuss the implications of our findings for the management of invasive plant species and the management of pest resistance to new crop protectants or varieties.

  14. Construction of predictive promoter models on the example of antibacterial response of human epithelial cells

    Directory of Open Access Journals (Sweden)

    Wingender Edgar

    2005-01-01

    Full Text Available Abstract Background Binding of a bacteria to a eukaryotic cell triggers a complex network of interactions in and between both cells. P. aeruginosa is a pathogen that causes acute and chronic lung infections by interacting with the pulmonary epithelial cells. We use this example for examining the ways of triggering the response of the eukaryotic cell(s, leading us to a better understanding of the details of the inflammatory process in general. Results Considering a set of genes co-expressed during the antibacterial response of human lung epithelial cells, we constructed a promoter model for the search of additional target genes potentially involved in the same cell response. The model construction is based on the consideration of pair-wise combinations of transcription factor binding sites (TFBS. It has been shown that the antibacterial response of human epithelial cells is triggered by at least two distinct pathways. We therefore supposed that there are two subsets of promoters activated by each of them. Optimally, they should be "complementary" in the sense of appearing in complementary subsets of the (+-training set. We developed the concept of complementary pairs, i.e., two mutually exclusive pairs of TFBS, each of which should be found in one of the two complementary subsets. Conclusions We suggest a simple, but exhaustive method for searching for TFBS pairs which characterize the whole (+-training set, as well as for complementary pairs. Applying this method, we came up with a promoter model of antibacterial response genes that consists of one TFBS pair which should be found in the whole training set and four complementary pairs. We applied this model to screening of 13,000 upstream regions of human genes and identified 430 new target genes which are potentially involved in antibacterial defense mechanisms.

  15. Evaluation of Antibacterial Potentiality of a Cyclopenta Naphthalene Tetraol Terpenoid Isolated from Curcuma caesia Roxb.

    Directory of Open Access Journals (Sweden)

    Padma Chatterjee

    2014-03-01

    Full Text Available The assessment of antibacterial potentiality of 2,3,4,8a,9,9a-hexamethyl-2,3,3a,4,4a,5,8,8a,9,9a – decahydro - 1H – cyclopenta [b] naphthalene -1,2,3a,4a-tetraol was the primary objective of this paper followed by its physicochemical characterization. Chemical characterisation of 2, 3, 4, 8a, 9, 9a-hexamethyl-2,3,3a,4,4a,5,8,8a,9,9a-decahydro-1H-cyclopenta [b] naphthalene-1,2,3a,4a-tetraol was done through UV, IR (FT-IR, HRMS and NMR spectroscopic techniques. Assessment of its antibacterial activity was performed using agar cup method and disc diffusion assay respectively. The antibacterial compound was terpenoid in nature and identified as 2, 3, 4, 8a, 9, 9a-hexamethyl-2,3,3a,4,4a,5,8,8a,9,9a-decahydro-1H-cyclopenta [b] naphthalene-1,2,3a,4a-tetraol. The MIC values tested against different plant pathogenic fungi and bacteria are different. The MIC values of this compound was 365 μg/ml, 274 μg/ml, 389 μg/ml, 443 μg/ml tested against the bacterium Serratia marcescens, Erwinia herbicola, Xanthomonas sp. and Arthrobacter chlorophenolicus respectively. Best of our knowledge this was the first report of presence of 2, 3, 4, 8a, 9, 9a-hexamethyl-2, 3, 3a, 4, 4a, 5, 8, 8a, 9, 9a-decahydro-1H-cyclopenta [b] naphthalene-1,2,3a,4a-tetraol in plants. Due to its antibacterial property it may function in plant defense or commercialize as an ecofriendly crop protectant.

  16. Transcriptome dynamics of a broad host-range cyanophage and its hosts.

    Science.gov (United States)

    Doron, Shany; Fedida, Ayalla; Hernández-Prieto, Miguel A; Sabehi, Gazalah; Karunker, Iris; Stazic, Damir; Feingersch, Roi; Steglich, Claudia; Futschik, Matthias; Lindell, Debbie; Sorek, Rotem

    2016-06-01

    Cyanobacteria are highly abundant in the oceans and are constantly exposed to lytic viruses. The T4-like cyanomyoviruses are abundant in the marine environment and have broad host-ranges relative to other cyanophages. It is currently unknown whether broad host-range phages specifically tailor their infection program for each host, or employ the same program irrespective of the host infected. Also unknown is how different hosts respond to infection by the same phage. Here we used microarray and RNA-seq analyses to investigate the interaction between the Syn9 T4-like cyanophage and three phylogenetically, ecologically and genomically distinct marine Synechococcus strains: WH7803, WH8102 and WH8109. Strikingly, Syn9 led a nearly identical infection and transcriptional program in all three hosts. Different to previous assumptions for T4-like cyanophages, three temporally regulated gene expression classes were observed. Furthermore, a novel regulatory element controlled early-gene transcription, and host-like promoters drove middle gene transcription, different to the regulatory paradigm for T4. Similar results were found for the P-TIM40 phage during infection of Prochlorococcus NATL2A. Moreover, genomic and metagenomic analyses indicate that these regulatory elements are abundant and conserved among T4-like cyanophages. In contrast to the near-identical transcriptional program employed by Syn9, host responses to infection involved host-specific genes primarily located in hypervariable genomic islands, substantiating islands as a major axis of phage-cyanobacteria interactions. Our findings suggest that the ability of broad host-range phages to infect multiple hosts is more likely dependent on the effectiveness of host defense strategies than on differential tailoring of the infection process by the phage. PMID:26623542

  17. Strategic defense initiative: critical issues

    Energy Technology Data Exchange (ETDEWEB)

    Nuckolls, J.H.

    1985-06-01

    The objectives of the Strategic Defense Initiative (SDI) as outlined by President Reagan are discussed. The principal objective for SDI is as a defense against ballistic missiles. Soviet objections and a summary of US-USSR dialogue on the subject are reviewed. Most US studies have been critical of SDI. Four critical issues are addressed in depth: are defense weapons technologically feasible which have high economic leverage relative to offensive ballistic missiles; would the defense feasibility and leverage be degraded or enhanced in the technological race between weapons innovation and countermeasures; could stability be achieved during and after the transition to the defense dominated world envisioned by SDI proponents; would the deployment of high leverage defensive weapons increase or decrease the security of NATO Europe, and the probability of major conventional or nuclear wars. The issue of SDI may lead to a paradox that contains the seeds of catastrophe. The author concludes by warning that nuclear disarmament may eliminate the highly successful deterrent mechanism for avoiding another major world war. In a world made safe for major conventional wars by the apparent ''elimination'' of nuclear weapons, the leaders in a conventional World War III - involving unimaginable suffering, hatred, terror, and death - would be strongly motivated to introduce nuclear weapons in the crucial decisive battles. Even if diplomacy could ''eliminate'' nuclear weapons, man's knowledge of nuclear weapons can never be eliminated. The paradox is the attempt to eliminate nuclear weapons may maximize the probability of their use. (DMC)

  18. Parasotoid communities and genetic structure: host plant does not matter

    OpenAIRE

    Jourdie, Violaine; Turlings, Ted

    2008-01-01

    Plant-insect interactions have long been studied and reveal intricate mechanisms. Plants are capable of defending themselves both directly by poisoning insect herbivores and indirectly by emitting volatile compounds that are used by the natural enemies to localize their host. In response, insects have evolved strategies to defeat plant defense mechanisms. Because insect pests are affected by plant signals, their natural enemies also bear these effects. As host plant can affect the physiology ...

  19. Factors affecting larval tick feeding success: host, density and time

    OpenAIRE

    Cami R Jones; Brunner, Jesse L.; Scoles, Glen A.; Jeb P Owen

    2015-01-01

    Background Ectoparasites rely on blood-feeding to sustain activity, support development and produce offspring. Blood-feeding is also a route for transmission of diverse vector-borne pathogens. The likelihood of successfully feeding is thus an important aspect of ectoparasite population dynamics and pathogen transmission. Factors that affect blood-feeding include ectoparasite density, host defenses, and ages of the host and ectoparasite. How these factors interact to affect feeding success is ...

  20. RNase 7 in Cutaneous Defense

    Science.gov (United States)

    Rademacher, Franziska; Simanski, Maren; Harder, Jürgen

    2016-01-01

    RNase 7 belongs to the RNase A superfamily and exhibits a broad spectrum of antimicrobial activity against various microorganisms. RNase 7 is expressed in human skin, and expression in keratinocytes can be induced by cytokines and microbes. These properties suggest that RNase 7 participates in innate cutaneous defense. In this review, we provide an overview about the role of RNase 7 in cutaneous defense with focus on the molecular mechanism of the antimicrobial activity of RNase 7, the regulation of RNase 7 expression, and the role of RNase 7 in skin diseases. PMID:27089327

  1. 76 FR 28757 - Defense Logistics Agency Revised Regulation 1000.22, Environmental Considerations in Defense...

    Science.gov (United States)

    2011-05-18

    ...-6221. Hand Delivery/Courier: Mr. Phillip R. Dawson, Defense Logistics Agency, DLA Installation Support... of the Secretary Defense Logistics Agency Revised Regulation 1000.22, Environmental Considerations in Defense Logistics Agency Actions AGENCY: Defense Logistics Agency, Department of Defense. ACTION:...

  2. 76 FR 53119 - Defense Logistics Agency Revised Regulation 1000.22, Environmental Considerations in Defense...

    Science.gov (United States)

    2011-08-25

    ... of Availability (NOA) in the Federal Register (76 FR 28757) announcing the revised Defense Logistics... Office of the Secretary Defense Logistics Agency Revised Regulation 1000.22, Environmental Considerations in Defense Logistics Agency Actions AGENCY: Defense Logistics Agency, Department of Defense....

  3. Are you my symbiont? Microbial polymorphic toxins and antimicrobial compounds as honest signals of beneficial symbiotic defensive traits.

    Science.gov (United States)

    Hillman, Kai; Goodrich-Blair, Heidi

    2016-06-01

    In defensive symbioses where microbes benefit their host by killing competitors, predators or parasites, natural selection should favor the transmission of microbes with the most beneficial defensive traits. During the initiation of symbiosis, the host's ability to accurately pre-assess a symbiont's beneficial traits would be a selective advantage. We propose that one mechanism by which a host could recognize and select a beneficial partner would be if the latter displayed an honest signal of its defensive or other symbiotic capabilities. As one example, we suggest that polymorphic toxins and their surface receptors, which are involved in inter-microbial competition and predator killing activities, can be honest signals that facilitate partner choice in defensive symbioses. PMID:27128187

  4. [Tuberculosis in compromised hosts].

    Science.gov (United States)

    2003-11-01

    Recent development of tuberculosis in Japan tends to converge on a specific high risk group. The proportion of tuberculosis developing particularly from the compromised hosts in the high risk group is especially high. At this symposium, therefore, we took up diabetes mellitus, gastrectomy, dialysis, AIDS and the elderly for discussion. Many new findings and useful reports for practical medical treatment are submitted; why these compromised hosts are predisposed to tuberculosis, tuberculosis diagnostic and remedial notes of those compromised hosts etc. It is an important question for the future to study how to prevent tuberculosis from these compromised hosts. 1. Tuberculosis in diabetes mellitus: aggravation and its immunological mechanism: Kazuyoshi KAWAKAMI (Department of Internal Medicine, Division of Infectious Diseases, Graduate School and Faculty of Medicine, University of the Ryukyus). It has been well documented that diabetes mellitus (DM) is a major aggravating factor in tuberculosis. The onset of this disease is more frequent in DM patients than in individuals with any underlying diseases. However, the precise mechanism of this finding remains to be fully understood. Earlier studies reported that the migration, phagocytosis and bactericidal activity of neutrophils are all impaired in DM patients, which is related to their reduced host defense to infection with extracellular bacteria, such as S. aureus and E. colli. Host defense to mycobacterial infection is largely mediated by cellular immunity, and Th1-related cytokines, such as IFN-gamma and IL-12, play a central role in this response. It is reported that serum level of these cytokines and their production by peripheral blood mononuclear cells (PBMC) are reduced in tuberculosis patients with DM, and this is supposed to be involved in the high incidence of tuberculosis in DM. Our study observed similar findings and furthermore indicated that IFN-gamma and IL-12 production by BCG-stimulated PBMC was lower

  5. Host-parasitoid relationships of Anagyrus sp. near pseudococci (Girault), (Hymenoptera, Encyrtidae), as a basis to improve biological control of pest mealybugs (Hemiptera, Pseudococcidae)

    OpenAIRE

    Bugila, Abdalbaset Abusalah Ali

    2014-01-01

    The host-parasitoid relationships of Anagyrus sp. nr. pseudococci were investigated, including host selection behavior, host defenses, host suitability and parasitoid functional response in relation to five mealybug species with different phylogenetic relationships and geographical origins: i) a Mediterranean native species, Planococcus ficus, with a long co-evolutionary history with the parasitoid; ii) three alien species, Planococcus citri, Pseudococcus calceolariae and Pseud...

  6. Systemic defense signaling in tomato

    Institute of Scientific and Technical Information of China (English)

    LI Changbao; SUN Jiaqiang; JIANG Hongling; WU Xiaoyan; LI Chuanyou

    2005-01-01

    The wound-inducible expression of proteinase inhibitors (PIs) genes in tomato provides a powerful model system to elucidate the signal transduction pathway of sys- temic defense response. An increasing body of evidence indi- cates that systemin and jasmonic acid (JA) work in the same signaling pathway to activate the expression of PIs and other defense-related genes. However, little is known about how systemin and JA interact to regulate cell to cell communica- tion over long distances. Genetic analysis of the systemin/JA signaling pathway in tomato plants provides a unique opportunity to dissect the mechanism by which peptide and oxylipin signals interact to coordinate systemic expression of defense-related genes. Previously, it has been proposed that systemin is the long-distance mobile signal for systemic expression of defense related genes. However, recent genetic approach provided new evidence that jasmonic acid, rather than systemin, functions as the systemic wound signal, and that the peptide systemin works to regulate the biosynthesis of JA.

  7. What Happens After the Defense?

    DEFF Research Database (Denmark)

    Feldtmann, Birgit

    2015-01-01

    who has attempted to attack the master’s vessel and whose distress is the direct result of lawful self-defense by PCASP? This is the question at the heart of this article, which argues that there are certain post incident obligations and that it is crucial to address these obligations at the flag...

  8. Soviet debate on missile defense

    Energy Technology Data Exchange (ETDEWEB)

    Parrott, B.

    1987-04-01

    Although the Strategic Defense Initiative (SDI) is meant to cope with the danger of a Soviet nuclear attack, the recent US debate over SDI has paid surprisingly little attention to Soviet views of ballistic missile defense. Despite the existence of a substantial body of pertinent scholarship, the debate has failed to take adequate account of major changes in Soviet ballistic missile defense policy since the mid-1960s. It has also neglected the links between current Soviet military policy and broader Soviet political and economic choices. The Soviets regard SDI not as a novel undertaking to reduce the risks of nuclear war but as an extension of the geopolitical competition between the superpowers. This competition has been dominated in the 1980s, in the Soviet view, by sharply increased US assertiveness and the decline of detente. Viewing SDI as a manifestation of these general trends, Soviet decision makers find the prospect of an unregulated race in ballistic missile defenses and military space technologies deeply unsettling. The deterioration of superpower relations has raised serious doubts in Moscow about the wisdom of Soviet external policy during the 1970s and has provoked sharp internal differences over policy toward the US. Already highly suspicious of the Reagan administration, the elite is united by a general conviction that SDI is an American gambit that may ultimately undercut past Soviet strategic gains and pose a grave new threat to Soviet security. 14 references.

  9. Characterization of antibacterial silver coated yarns.

    Science.gov (United States)

    Pollini, M; Russo, M; Licciulli, A; Sannino, A; Maffezzoli, A

    2009-11-01

    Surface treatments of textile fibers and fabrics significantly increase their performances for specific biomedical applications. Nowadays, silver is the most used antibacterial agent with a number of advantages. Among them, it is worth to note the high degree of biocompatibility, an excellent resistance to sterilization conditions, antibacterial properties with respect to different bacteria associated with a long-term of antibacterial efficiency. However, there are only a few antibacterial fibres available, mainly synthetic with high production cost and limited effectiveness. Cotton yarns with antimicrobial properties are most suitable for wound healing applications and other medical treatments thanks to their excellent moisture absorbance while synthetic based fibres are most suitable for industrial applications such as automotive tapestry and air filters. The silver-coated fibers were developed applying an innovative and low cost silver deposition technique for natural and synthetic fibers or yarns. The structure and morphology of the silver nanoclusters on the fibers was observed by scanning electron microscopy (SEM), atomic force microscopy analysis (AFM) and XRD analysis, and quantitatively confirmed by thermogravimetric analysis (TGA) measurements. Good silver coating stability has been confirmed performing several industrial washing. Antimicrobial tests with Escherichia coli were performed. PMID:19526328

  10. Radiation modified cotton fibrils for antibacterial applications

    International Nuclear Information System (INIS)

    Full text: Quaternary ammonium groups, well known antibacterial agents, have been incorporated covalently onto cotton fabric via radiation induced grafting of (2-(Acryloyloxy)ethyl)trimethylammonium chloride (AETC) on to cotton fabric by mutual irradiation grafting technique using 60Co-gamma radiation source in presence of 2- Hydroxyethylmethacrylate (HEMA). Various experimental parameters have been optimized for development of antibacterial grafted cotton fabric. Grafting extent increased with dose but was an inverse function of dose rate. Grafting yield increased linearly with HEMA concentration but was not affected by AETC concentration in feed. N2 ambient was most effective during grafting. The grafted sample show significantly higher water uptake and water retention properties. Antibacterial activity of polymer, co-polymer and grafted samples were tested against four bacteria S. aureus, E.coli, B.cereus and P.fluorescens. The minimum bactericidal concentration (MBC) of poly(AETC) was in range 0.0025-0.2% depending on the bacteria. MBC followed the order S.aureus ∼ B.cereus< E.coli< P.fluorescens. The co-polymer of AETC and HEMA was found to be effective against S.aureus and B.cereus only. Antibacterial assay showed variations in activity between pure polymer and grafted cotton. The activity of grafted samples was less in comparison pure polymer, which may be due to its bound state on cotton

  11. Antibacterial properties of polyaniline-silver films

    Czech Academy of Sciences Publication Activity Database

    Kuceková, Z.; Kašpárková, V.; Humpolíček, P.; Ševčíková, P.; Stejskal, Jaroslav

    2013-01-01

    Roč. 67, č. 8 (2013), s. 1103-1108. ISSN 0366-6352 R&D Projects: GA ČR(CZ) GA13-08944S Institutional support: RVO:61389013 Keywords : polyaniline * silver * antibacterial properties Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.193, year: 2013

  12. Synthetic and Antibacterial Studies of Quinolinylchalcones

    Science.gov (United States)

    Azad, Muhammad; Munawar, Munawar Ali; Athar, Makshoof

    A series of quinolinyl chalcones have been prepared by the condensation of N-substituted-3-acetyl-4-hydroxyquinolin-2(1H)-ones with different aromatic aldehydes using conventional heating and ultrasound-assisted methods. The percentage yields are considerably increased in ultrasound-assisted method. The prepared chalcone derivatives were assayed for antibacterial and cytotoxicity and were found to be active.

  13. DRUG-INTERACTIONS WITH QUINOLONE ANTIBACTERIALS

    NARCIS (Netherlands)

    BROUWERS, JRBJ

    1992-01-01

    The quinolone antibacterials are prone to many interactions with other drugs. Quinolone absorption is markedly reduced with antacids containing aluminium, magnesium and/or calcium and therapeutic failure may result. Other metallic ion-containing drugs, such as sucralfate, iron salts, and zinc salts,

  14. Antibacterial effect of protamine assayed by impedimetry

    DEFF Research Database (Denmark)

    Johansen, Charlotte; Gill, T.; Gram, Lone

    1995-01-01

    Impedimetric measurements were used to assay the antibacterial effect of protamine. A good linear correlation between the impedance detection time and the initial cell counts was obtained (r = 0 . 99, n = 2). As basic peptides may cause clumping of cells, this correlation curve was used when...

  15. Antibacterial paperboard packaging using microfibrillated cellulose.

    Science.gov (United States)

    Lavoine, Nathalie; Desloges, Isabelle; Manship, Brigitte; Bras, Julien

    2015-09-01

    The industry and consumers are focusing more and more on the development of biodegradable and lightweight food-packaging materials, which could better preserve the quality of the food and improve its shelf-life. In an attempt to meet these requirements, this study presents a novel bio-substrate able to contain active bio-molecules for future food-packaging applications. Based on a paperboard substrate, the development of an antibacterial bio-packaging material is, therein, achieved using a chlorhexidine digluconate (CHX) solution as a model of an antibacterial molecule, mixed with microfibrillated cellulose (MFC) and used as coating onto paperboard samples. AFM and FE-SEM analyses were performed to underline the nanoporous MFC network able to trap and to progressively release the CHX molecules. The release study of CHX was conducted in an aqueous medium and showed a lower proportion (20 %) of CHX released when using MFC. This led to the constant release of low amounts of CHX over 40 h. Antibacterial tests were carried out to assess the preservation of the antibacterial activity of the samples after the release studies. Samples remained active against Bacillus subtilis, with better results being obtained when MFC was used. The preservation of the quality of a model food was finally evaluated paving the way for future promising applications in the food packaging industry. PMID:26344972

  16. Plants versus Fungi and Oomycetes: Pathogenesis, Defense and Counter-Defense in the Proteomics Era

    Directory of Open Access Journals (Sweden)

    Abdelbasset El Hadrami

    2012-06-01

    Full Text Available Plant-fungi and plant-oomycete interactions have been studied at the proteomic level for many decades. However, it is only in the last few years, with the development of new approaches, combined with bioinformatics data mining tools, gel staining, and analytical instruments, such as 2D-PAGE/nanoflow-LC-MS/MS, that proteomic approaches thrived. They allow screening and analysis, at the sub-cellular level, of peptides and proteins resulting from plants, pathogens, and their interactions. They also highlight post-translational modifications to proteins, e.g., glycosylation, phosphorylation or cleavage. However, many challenges are encountered during in planta studies aimed at stressing details of host defenses and fungal and oomycete pathogenicity determinants during interactions. Dissecting the mechanisms of such host-pathogen systems, including pathogen counter-defenses, will ensure a step ahead towards understanding current outcomes of interactions from a co-evolutionary point of view, and eventually move a step forward in building more durable strategies for management of diseases caused by fungi and oomycetes. Unraveling intricacies of more complex proteomic interactions that involve additional microbes, i.e., PGPRs and symbiotic fungi, which strengthen plant defenses will generate valuable information on how pathosystems actually function in nature, and thereby provide clues to solving disease problems that engender major losses in crops every year.

  17. Role of Interleukin-17 in defense against pseudomonas aeruginosa infection in lungs

    OpenAIRE

    Xu, Xilin; Shao, Bing; Wang, Ran; ZHOU, SIJING; Tang, Zhongzhi; Lu, Weihua; XIONG, SHENGDAO

    2014-01-01

    Background: Pseudomonas aeruginosa may cause severe or even fatal infection in hosts with immunodeficiency. Interleukin-17 (IL-17) is a newly discovered pro-inflammatory cytokine, which promotes the recruitment and activation of neutrophils in the respiratory tract by inducing release of chemokine C-X-C. Objective: This study was conducted to explore the role of IL-17 in host defense against acute pseudomonas aeruginosa infection in lungs. Methods: The expression of IL-17 and its downstream e...

  18. The Barrier to Autointegration Factor: Interlocking Antiviral Defense with Genome Maintenance.

    Science.gov (United States)

    Wiebe, Matthew S; Jamin, Augusta

    2016-04-15

    Intrinsic defenses targeting foreign DNA are one facet of the cellular armament tasked with protecting host genomic integrity. The DNA binding protein BAF (barrier to autointegration factor) contributes to multiple aspects of genome maintenance and intercepts retrovirus, poxvirus, and herpesvirus genomes during infection. In this gem, we discuss the unique position BAF occupies at the virus-host interface and how both viral and cellular mechanisms may regulate its capacity to act as a pro- or antiviral effector targeting viral DNA. PMID:26842478

  19. Tick-Host Specificity

    OpenAIRE

    Hoogstraal, H.; Aeschlimann, André

    2010-01-01

    A review the various patterns of tick-host relationships are discussed in detail in order to answer the following questions : 1. How, when and where did host specificity of each parasite group evolve ? 2. How strict is specificity in each case ? 3. Why and under what circumstances does specificity break down ? The authors present several definitions which characterize the various degrees of parasitic specificity existing today between ticks and their hosts. Tick-host relationships are ...

  20. A tritrophic signal that attracts parasitoids to host-damaged plants withstands disruption by non-host herbivores

    Directory of Open Access Journals (Sweden)

    Turlings Ted CJ

    2010-11-01

    Full Text Available Abstract Background Volatiles emitted by herbivore-infested plants are highly attractive to parasitoids and therefore have been proposed to be part of an indirect plant defense strategy. However, this proposed function of the plant-provided signals remains controversial, and it is unclear how specific and reliable the signals are under natural conditions with simultaneous feeding by multiple herbivores. Phloem feeders in particular are assumed to interfere with plant defense responses. Therefore, we investigated how attack by the piercing-sucking cicadellid Euscelidius variegatus influences signaling by maize plants in response to the chewing herbivore Spodoptera littoralis. Results The parasitoid Cotesia marginiventris strongly preferred volatiles of plants infested with its host S. littoralis. Overall, the volatile emissions induced by S. littoralis and E. variegatus were similar, but higher levels of certain wound-released compounds may have allowed the wasps to specifically recognize plants infested by hosts. Expression levels of defense marker genes and further behavioral bioassays with the parasitoid showed that neither the physiological defense responses nor the attractiveness of S. littoralis infested plants were altered by simultaneous E. variegatus attack. Conclusions Our findings imply that plant defense responses to herbivory can be more robust than generally assumed and that ensuing volatiles convey specific information about the type of herbivore that is attacking a plant, even in complex situations with multiple herbivores. Hence, the results of this study support the notion that herbivore-induced plant volatiles may be part of a plant's indirect defense stratagem.

  1. Susceptibility of Porphyromonas gingivalis and Streptococcus mutans to Antibacterial Effect from Mammea americana

    Directory of Open Access Journals (Sweden)

    Alejandra Herrera Herrera

    2014-01-01

    Full Text Available The development of periodontal disease and dental caries is influenced by several factors, such as microorganisms of bacterial biofilm or commensal bacteria in the mouth. These microorganisms trigger inflammatory and immune responses in the host. Currently, medicinal plants are treatment options for these oral diseases. Mammea americana extracts have reported antimicrobial effects against several microorganisms. Nevertheless, this effect is unknown against oral bacteria. Therefore, the aim of this study was to evaluate the antibacterial effect of M. americana extract against Porphyromonas gingivalis and Streptococcus mutans. For this, an experimental study was conducted. Ethanolic extract was obtained from seeds of M. americana (one oil phase and one ethanolic phase. The strains of Porphyromonas gingivalis ATCC 33277 and Streptococcus mutans ATCC 25175 were exposed to this extract to evaluate its antibacterial effect. Antibacterial activity was observed with the two phases of M. americana extract on P. gingivalis and S. mutans with lower MICs (minimum inhibitory concentration. Also, bactericidal and bacteriostatic activity was detected against S. mutans, depending on the concentration of the extract, while on M. americana extract presented only bacteriostatic activity against P. gingivalis. These findings provide important and promising information allowing for further exploration in the future.

  2. Activation of Hepatic STAT3 Maintains Pulmonary Defense during Endotoxemia.

    Science.gov (United States)

    Hilliard, Kristie L; Allen, Eri; Traber, Katrina E; Kim, Yuri; Wasserman, Gregory A; Jones, Matthew R; Mizgerd, Joseph P; Quinton, Lee J

    2015-10-01

    Pneumonia and infection-induced sepsis are worldwide public health concerns. Both pathologies elicit systemic inflammation and induce a robust acute-phase response (APR). Although APR activation is well regarded as a hallmark of infection, the direct contributions of liver activation to pulmonary defense during sepsis remain unclear. By targeting STAT3-dependent acute-phase changes in the liver, we evaluated the role of liver STAT3 activity in promoting host defense in the context of sepsis and pneumonia. We employed a two-hit endotoxemia/pneumonia model, whereby administration of 18 h of intraperitoneal lipopolysaccharide (LPS; 5 mg/kg of body weight) was followed by intratracheal Escherichia coli (10(6) CFU) in wild-type mice or those lacking hepatocyte STAT3 (hepSTAT3(-/-)). Pneumonia alone (without endotoxemia) was effectively controlled in the absence of liver STAT3. Following endotoxemia and pneumonia, however, hepSTAT3(-/-) mice, with significantly reduced levels of circulating and airspace acute-phase proteins, exhibited significantly elevated lung and blood bacterial burdens and mortality. These data suggested that STAT3-dependent liver responses are necessary to promote host defense. While neither recruited airspace neutrophils nor lung injury was altered in endotoxemic hepSTAT3(-/-) mice, alveolar macrophage reactive oxygen species generation was significantly decreased. Additionally, bronchoalveolar lavage fluid from this group of hepSTAT3(-/-) mice allowed greater bacterial growth ex vivo. These results suggest that hepatic STAT3 activation promotes both cellular and humoral lung defenses. Taken together, induction of liver STAT3-dependent gene expression programs is essential to countering the deleterious consequences of sepsis on pneumonia susceptibility. PMID:26216424

  3. Incompatibility between plant-derived defensive chemistry and immune response of two sphingid herbivores.

    Science.gov (United States)

    Lampert, Evan C; Bowers, M Deane

    2015-01-01

    Herbivorous insects use several different defenses against predators and parasites, and tradeoffs among defensive traits may occur if these traits are energetically demanding. Chemical defense and immune response potentially can interact, and both can be influenced by host plant chemistry. Two closely related caterpillars in the lepidopteran family Sphingidae are both attacked by the same specialist endoparasitoid species but have mostly non-overlapping host plant ranges that differ in secondary chemistry. Ceratomia catalpae is a specialist on Catalpa and also will feed on Chilopsis, which both produce iridoid glycosides. Ceratomia undulosa consumes members of the Oleaceae, which produce seco-iridoid glycosides. Immune response of the two species on a typical host plant species (Catalpa bignonioides for C. catalpa; Fraxinus americana for C. undulosa) was compared using a melanization assay, and did not differ. In a second experiment, the iridoid glycoside catalpol was added to the diets of both insects, and growth rate, mass, chemical defense, and immune response were evaluated. Increased dietary catalpol weakened the immune response of C. undulosa and altered the development rate of C. catalpae by prolonging the third instar and accelerating the fourth instar. Catalpol sequestration was negatively correlated with immune response of C. catalpae, while C. undulosa was unable to sequester catalpol. These results show that immune response can be negatively influenced by increasing concentrations of sequestered defensive compounds. PMID:25516226

  4. Department of Defense PERSEREC (DOD PERSEREC)

    Data.gov (United States)

    Social Security Administration — The purpose of this agreement is for SSA to verify SSN information for Defense Manpower Data Center (DMDC) of the Department of Defense. DMDC will use the SSA data...

  5. Defense Programs Transportation Risk Assessment

    International Nuclear Information System (INIS)

    This paper provides an overview of the methodology used in a probabilistic transportation risk assessment conducted to assess the probabilities and consequences of inadvertent dispersal of radioactive materials arising from severe transportation accidents. The model was developed for the Defense Program Transportation Risk Assessment (DPTRA) study. The analysis incorporates several enhancements relative to previous risk assessments of hazardous materials transportation including newly-developed statistics on the frequencies and severities of tractor semitrailer accidents and detailed route characterization using the 1990 Census data

  6. Territorial Defense, Education, and Interculturalism

    OpenAIRE

    Claudia Patricia Sierra Pardo

    2011-01-01

    The article carries out a series of reflections regarding the social and economic conditions in which the cultivation of oil palm affected the Bajo Atrato region of the Department of Chocó at the end of the nineteen nineties. It also discusses the actions carried out by communities, companies, and organizations in solidarity with the region’s cause, since these expressions make it possible to understand the role of organization and education in territorial defense processes. Finally, the arti...

  7. Second Line of Defense Spares Program

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, Dale L.; Holmes, Aimee E.; Muller, George; Mercier, Theresa M.; Brigantic, Robert T.; Perkins, Casey J.; Cooley, Scott K.; Thorsen, Darlene E.

    2012-11-20

    During Fiscal Year 2012, a team from the Pacific Northwest National Laboratory (PNNL) conducted an assessment and analysis of the Second Line of Defense (SLD) Sustainability spare parts program. Spare parts management touches many aspects of the SLD Sustainability Program including contracting and integration of Local Maintenance Providers (LMP), equipment vendors, analyses and metrics on program performance, system state of health, and maintenance practices. Standardized spares management will provide better data for decisions during site transition phase and will facilitate transition to host country sustainability ownership. The effort was coordinated with related SLD Sustainability Program initiatives, including a configuration items baselining initiative, a metrics initiative, and a maintenance initiative. The spares study has also led to pilot programs for sourcing alternatives that include regional intermediate inventories and partnering agreements that leverage existing supply chains. Many partners from the SLD Sustainability program contributed to and were consulted in the course of the study. This document provides a description of the findings, recommendations, and implemented solutions that have resulted from the study.

  8. Host-Bacteria Crosstalk at the Dentogingival Junction

    Directory of Open Access Journals (Sweden)

    M. T. Pöllänen

    2012-01-01

    Full Text Available The dentogingival junction is of crucial importance in periodontal host defense both structurally and functionally. Oral bacteria exert a constant challenge to the host cells and tissues at the dentogingival junction. The host response is set up to eliminate the pathogens by the innate and adaptive defense mechanisms. In health, the commensal bacteria and the host defense mechanisms are in a dynamic steady state. During periodontal disease progression, the dental bacterial plaque, junctional epithelium (JE, inflammatory cells, connective tissue, and bone all go through a series of changes. The tissue homeostasis is turned into tissue destruction and progression of periodontitis. The classical study of Slots showed that in the bacterial plaque, the most remarkable change is the shift from gram-positive aerobic and facultatively anaerobic flora to a predominantly gram-negative and anaerobic flora. This has been later confirmed by several other studies. Furthermore, not only the shift of the bacterial flora to a more pathogenic one, but also bacterial growth as a biofilm on the tooth surface, allows the bacteria to communicate with each other and exert their virulence aimed at favoring their growth. This paper focuses on host-bacteria crosstalk at the dentogingival junction and the models studying it in vitro.

  9. CSRF Vulnerabilities and Defensive Techniques

    Directory of Open Access Journals (Sweden)

    Rupali D. Kombade

    2012-02-01

    Full Text Available Web applications are now part of day to day life due to their user friendly environment as well as advancement of technology to provide internet facilities, but these web applications brought lot of threats with them and these threats are continuously growing, one of the these threat is Cross Site Request Forgery(CSRF. CSRF attack is immerged as serious threat to web applications which based on the vulnerabilities present in the normal request response pattern of HTTP protocol. It is difficult to detect and hence it is present in most of the existing web applications. CSRF attack occurs when a malicious web site causes a user’s web browser to perform an unwanted action on a trusted site. It is listed in OWASP’s top ten Web Application attacks list. In this survey paper we will study CSRF attack, CSRF vulnerabilities and its defensive measures. We have compared various defense mechanisms to analyse the best defense mechanism. This study will help us to build strong and robust CSRF protection mechanism.

  10. Nicotine's Defensive Function in Nature

    Directory of Open Access Journals (Sweden)

    Steppuhn Anke

    2004-01-01

    Full Text Available Plants produce metabolites that directly decrease herbivore performance, and as a consequence, herbivores are selected for resistance to these metabolites. To determine whether these metabolites actually function as defenses requires measuring the performance of plants that are altered only in the production of a certain metabolite. To date, the defensive value of most plant resistance traits has not been demonstrated in nature. We transformed native tobacco(Nicotiana attenuata with a consensus fragment of its two putrescine N-methyl transferase (pmt genes in either antisense or inverted-repeat (IRpmt orientations. Only the latter reduced (by greater than 95% constitutive and inducible nicotine. With D4-nicotinic acid (NA, we demonstrate that silencing pmt inhibits nicotine production, while the excess NA dimerizes to form anatabine. Larvae of the nicotine-adapted herbivore Manduca sexta (tobacco hornworm grew faster and, like the beetle Diabrotica undecimpunctata, preferred IRpmt plants in choice tests. When planted in their native habitat, IRpmt plants were attacked more frequently and, compared to wild-type plants, lost 3-fold more leaf area from a variety of native herbivores, of which the beet armyworm, Spodoptera exigua, and Trimerotropis spp. grasshoppers caused the most damage. These results provide strong evidence that nicotine functions as an efficient defense in nature and highlights the value of transgenic techniques for ecological research.

  11. Defense gene expression profiling of a wheat-Pseudomonas biocontrol interaction

    Science.gov (United States)

    In wheat (Triticum aestivum), specific root-colonizing strains of the bacterium P. fluorescens confer protection against soilborne fungal pathogens, but their role in inducing host defense responses is not fully known. To address this information gap, we sorted and annotated over 16,745 root-expres...

  12. A novel mechanism for NETosis provides antimicrobial defense at the oral mucosa

    DEFF Research Database (Denmark)

    Mohanty, Tirthankar; Sjögren, Jonathan; Kahn, Fredrik;

    2015-01-01

    Neutrophils are essential for host defense at the oral mucosa and neutropenia or functional neutrophil defects lead to disordered oral homeostasis. We found that neutrophils from the oral mucosa harvested from morning saliva had released neutrophil extracellular traps (undergone NETosis) in vivo...

  13. Genome adaptations of a tripartite motif protein for retroviral defense in cattle and sheep

    Science.gov (United States)

    Tripartite motif (TRIM) genes encode proteins composed of RING, B-box, and coiled coil motif domains. Primate TRIM5' has been shown to be a primary determinant of retroviral host cell range restriction in primates. TRIM5 restriction was originally thought to be a primate-specific defense mechanism...

  14. Quantifying the dynamics of viruses and the cellular immune response of the host

    NARCIS (Netherlands)

    Althaus, C.L.

    2009-01-01

    Infections can be caused by viruses, which attack certain cells within an infected host. However, the immune system of the host has evolved remarkable defense mechanisms that counter against an infection. In particular, so-called cytotoxic T lymphocytes can recognize and eliminate infected cells. Th

  15. 22 CFR 120.6 - Defense article.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Defense article. 120.6 Section 120.6 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS PURPOSE AND DEFINITIONS § 120.6 Defense article. Defense article means any item or technical data designated in § 121.1 of this...

  16. Teaching Gibb's Taxonomy of Defensiveness through Performance

    Science.gov (United States)

    Thomson, Deborah M.

    2008-01-01

    The topic of defensiveness resonates with students, who are generally eager to learn how to prevent it. Gibb's taxonomy of defensive/supportive behaviors is widely published and used today. According to Gibb, defensiveness occurs when a communicator puts substantial effort into defending him/herself from a perceived communicative threat. This…

  17. Evaluation of in vitro antibacterial effect of room curing polymethylmethacrylate material adding nano-silver base inorganic antibacterial agents

    International Nuclear Information System (INIS)

    Objective: To investigate the antibacterial effect of room curing polymethylmethacrylate (PMMA) material adding nano-silver base inorganic antibacterial agent and to detect the changes of its mechanical property. Methods: Nano-silver base inorganic antibacterial agent was added to the room curing PMMA material in the range of 0.5% -3.0% at an interval of 0.5% by ball milling specimen. Antibacterial rates of the specimens were detected by film method. Bending strength, impact strength, and wear resistance of the specimens were respectively detected on electronic universal testing machine, impact test machine and friction and wear test machine. Results: The antibacterial rates of Streptococcus mutans and Candida albicans were more than 50% when antibiotics content was 1.0% . The antibacterial rates of Streptococcus mutans and Candida albicans were more than 90% when the antibiotics content was 2.5% . The three mechanical properties were increased compared with control group when the antibacterial agents were in the range of 1.0% -1.5% . Then the three mechanical properties were decreased with the increasing of antimicrobial concentration. When the antibiotics content was 2.0% , the wear resistance had significant difference compared with control group (P<0.05); when the antibiotics content was 2.5% , the bending strength and impact strength had significant difference compared with control group (P<0.05). Conclusion: The antibacterial effect of room curing PMMA adding nano-silver base inorganic antibacterial agent is ideal. The antibacterial rate is increased gradually with the increasing content of antibacterial agents. There is no significant effect on the mechanical properties of room curing PMMA material, but the antibacterial effects are satisfied when the content of antibacterial agents is 2.0% . (authors)

  18. Synthesis of highly efficient antibacterial agent Ag doped ZnO nanorods: Structural, Raman and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Jan, Tariq; Iqbal, Javed, E-mail: javed.saggu@iiu.edu.pk [Laboratory of Nanoscience and Technology, Department of Physics, International Islamic University Islamabad (Pakistan); Ismail, Muhammad [Institute of Biomedical and Genetic Engineering (IBGE), Islamabad (Pakistan); Mahmood, Arshad [Nano Devices Labs, National Institute of Lasers and Optronics, Islamabad (Pakistan)

    2014-04-21

    Here, synthesis, structural, morphological, Raman, optical properties and antibacterial activity of undoped and Ag doped ZnO nanorods by chemical co-precipitation technique have been reported. Structural analysis has revealed that Ag doping cannot deteriorate the structure of ZnO and wurtzite phase is maintained. Lattice constants are found to be decreased with the Ag doping. Fourier transform infrared and Raman spectroscopy also confirm the X-ray diffraction results. Scanning electron microscopy results have demonstrated the formation of ZnO nanorods with average diameter and length of 96 nm and 700 nm, respectively. Raman spectroscopy results suggest that the Ag doping enhances the number of defects in ZnO crystal. It has been found from optical study that Ag doping results in positional shift of band edge absorption peak. This is attributed to the successful incorporation of Ag dopant into ZnO host matrix. The antibacterial activity of prepared nanorods has been determined by two different methods and compared to that of undoped ZnO nanorods. Ag doped ZnO nanorods exhibit excellent antibacterial activity as compared to that of undoped ZnO nanorods. This excellent antibacterial activity may be attributed to the presence of oxygen vacancies and Zn{sup 2+} interstitial defects. Our preliminary findings suggest that Ag doped ZnO nanorods can be used externally to control the spreading of infections related with tested bacterial strains.

  19. ANTIBACTERIAL PROPERTIES AND DRYING EFFECTS OF FLAX DENIM AND ANTIBACTERIAL PROPERTIES OF NONWOVEN FLAX FABRIC

    Directory of Open Access Journals (Sweden)

    David T.W. Chun

    2010-02-01

    Full Text Available A modification of “AATCC Test Method 100-1999” was used for assaying for bacteriostatic/antibacterial properties of denim containing various flax concentrations. Since no direct evidence that increasing the flax content of fabric imparted the fabric with increased bacteriostatic properties was found against the control bacteria, Staphylococcus aureus and Klebsiella pneumoniae, other possible explanations for the long held presumption that flax fabric exhibited antibacterial properties was sought. Because the appearance of having antibacterial or bacteriostatic properties might be imitated if the flax content would decrease the time fabric would be moist enough for bacterial growth, the effect of drying was evaluated. When flax fabric was saturated and the moisture lost during incubation was measured, there was no improved drying associated with increased flax content. When untreated nonwoven flax was evaluated as possibly containing more ‘antibacterial’ or bacteriostatic components than scoured nonwoven flax material, the population densities increased. This increase suggests that the unscoured nonwoven flax contain compo-nents that support bacterial growth to the extent that bacteriostatic or antibacterial components, if any, are overwhelmed by the components that support bacterial growth. In tests involving the control bacteria, Staphylococcus aureus and Klebsiella pneumoniae, increasing the flax content of flax fabric did not demonstrate increased antibacterial properties.

  20. Light-activated polymethylmethacrylate nanofibers with antibacterial activity.

    Science.gov (United States)

    Elashnikov, Roman; Lyutakov, Oleksiy; Ulbrich, Pavel; Svorcik, Vaclav

    2016-07-01

    The creation of an antibacterial material with triggerable properties enables us to avoid the overuse or misuse of antibacterial substances and, thus, prevent the emergence of resistant bacterial strains. As a potential light-activated antibacterial material, polymethylmethacrylate (PMMA) nanofibers doped with silver nanoparticles (AgNPs) and meso-tetraphenylporphyrin (TPP) were prepared by electrospinning. TPP was chosen as an effectively reactive oxygen species (ROS) producer. Antibacterial tests on Staphylococcus epidermidis (S. epidermidis) and Enterococcus faecalis (E. faecalis) showed the excellent light-triggerable antibacterial activity of the doped materials. Upon light irradiation at the wavelength corresponding to the TPP absorption peak (405nm), antibacterial activity dramatically increased, mostly due to the release of AgNPs from the polymer matrix. Furthermore, under prolonged light irradiation, the AgNPs/TPP/PMMA nanofibers, displayed enhanced longevity and photothermal stability. Thus, our results suggest that the proposed material is a promising option for the photodynamic inactivation of bacteria. PMID:27127048

  1. Diversity and antibacterial activity of phyllosticta species

    Directory of Open Access Journals (Sweden)

    E. Chukeatirote

    2015-01-01

    Full Text Available Phyllosticta fungi are widely distributed and appear to have different lifestyles. Although some Phyllosticta species are known to cause plant diseases, others are useful due to their bioactive metabolites. In this study, we screened and isolated the Phyllosticta fungi from several plant specimens. In total, 67 Phyllosticta isolates were identified based on their distinct morphological characteristics. Of these, 18 isolates were pathogens and 49 isolates were endophytes. Besides, 61 isolates (91% were identified as P. capitalensis indicating its widespread distribution. Thirty Phyllosticta isolates were then selected for studying their antibacterial activity. For this, the fungal strains were cultured in potato dextrose broth and cultivated at 27 C for 2 weeks. The fungal mycelia were removed and the culture supernatants were extracted using ethyl acetate. Antibacterial activity screening was then carried out using an agar disc diffusion assay. Our data showed that most Phyllosticta crude extracts (87% were active and could inhibit at least one of the testing bacteria.

  2. 76 FR 72391 - Defense Logistics Agency Revised Regulation 1000.22, Environmental Considerations in Defense...

    Science.gov (United States)

    2011-11-23

    ... (DLA) published a Notice of Availability (NOA) in the Federal Register (76 FR 28757) announcing the... of the Secretary Defense Logistics Agency Revised Regulation 1000.22, Environmental Considerations in Defense Logistics Agency Actions AGENCY: Defense Logistics Agency, Department of Defense. ACTION:...

  3. Effect of a gall-inducing psylloid, Pseudophacopteron alstonium Yang et Li (Hemiptera: Phacopteronidae) on defensive chemistry of Alstonia scholaris (L.) R. Br. (Gentianales: Apocynaceae)

    OpenAIRE

    Yang, Zhen-De; Lv, Wen-Ling; Zheng, Xia-Lin; Yu, Shu-Zhong; Li, Ming

    2016-01-01

    Gall-inducing insect species are capable to escape from defence of host plant species. However, effect of gall-inducing insects on defensive mechanism of host plants is still unclear. The present study was conducted to evaluate the possible chemical changes in the defensive system of Alstonia scholaris (L.) R. Br. (Gentianales: Apocynaceae) caused by Pseudophacopteron alstonium Yang et Li (Hemiptera: Phacopteronidae) feeding. Total phenolic and tannin, peroxidase, superoxide dismutase, catala...

  4. Antibacterial biodegradable Mg-Ag alloys

    Directory of Open Access Journals (Sweden)

    D Tie

    2013-06-01

    Full Text Available The use of magnesium alloys as degradable metals for biomedical applications is a topic of ongoing research and the demand for multifunctional materials is increasing. Hence, binary Mg-Ag alloys were designed as implant materials to combine the favourable properties of magnesium with the well-known antibacterial property of silver. In this study, three Mg-Ag alloys, Mg2Ag, Mg4Ag and Mg6Ag that contain 1.87 %, 3.82 % and 6.00 % silver by weight, respectively, were cast and processed with solution (T4 and aging (T6 heat treatment.The metallurgical analysis and phase identification showed that all alloys contained Mg4Ag as the dominant β phase. After heat treatment, the mechanical properties of all Mg-Ag alloys were significantly improved and the corrosion rate was also significantly reduced, due to presence of silver. Mg(OH2 and MgO present the main magnesium corrosion products, while AgCl was found as the corresponding primary silver corrosion product. Immersion tests, under cell culture conditions, demonstrated that the silver content did not significantly shift the pH and magnesium ion release. In vitro tests, with both primary osteoblasts and cell lines (MG63, RAW 264.7, revealed that Mg-Ag alloys show negligible cytotoxicity and sound cytocompatibility. Antibacterial assays, performed in a dynamic bioreactor system, proved that the alloys reduce the viability of two common pathogenic bacteria, Staphylococcus aureus (DSMZ 20231 and Staphylococcus epidermidis (DSMZ 3269, and the results showed that the killing rate of the alloys against tested bacteria exceeded 90%. In summary, biodegradable Mg-Ag alloys are cytocompatible materials with adjustable mechanical and corrosion properties and show promising antibacterial activity, which indicates their potential as antibacterial biodegradable implant materials.

  5. Antibacterial nanofiber materials activated by light

    Czech Academy of Sciences Publication Activity Database

    Jesenská, S.; Plištil, L.; Kubát, Pavel; Lang, Kamil; Brožová, Libuše; Popelka, Štěpán; Szatmáry, Lórant; Mosinger, Jiří

    99A, č. 4 (2011), s. 676-683. ISSN 1549-3296 R&D Projects: GA ČR GAP208/10/1678 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z40320502; CEZ:AV0Z40500505 Keywords : antibacterial nanofiber materials * photoactive * singlet oxygen Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.625, year: 2011

  6. Chemical Composition and Antibacterial Effects of

    OpenAIRE

    SS Saei Dehkordi; H Tajik; Moradi, M; A Jafari Dehkordi; Ghasemi, S.

    2009-01-01

    Introduction & Objective: Rosmarinus officinalis L. as a member of the Lamiaceae family and lysozyme as a natural antibacterial agent is important in food microbiology, because of its characteristics. The aim of the present study was to determine the chemical composition and anti-listerial activity of Rosmarinus officinalis essential oil (REO) alone and in combination with lysozyme for enhancement of anti-listerial activity of both substances. Materials & Methods: Rosmarinus officinalis ...

  7. Honey: its medicinal property and antibacterial activity

    OpenAIRE

    Mandal, Manisha Deb; Mandal, Shyamapada

    2011-01-01

    Indeed, medicinal importance of honey has been documented in the world's oldest medical literatures, and since the ancient times, it has been known to possess antimicrobial property as well as wound-healing activity. The healing property of honey is due to the fact that it offers antibacterial activity, maintains a moist wound condition, and its high viscosity helps to provide a protective barrier to prevent infection. Its immunomodulatory property is relevant to wound repair too. The antimic...

  8. Actinopyga lecanora Hydrolysates as Natural Antibacterial Agents

    OpenAIRE

    Raheleh Ghanbari; Afshin Ebrahimpour; Azizah Abdul-Hamid; Amin Ismail; Nazamid Saari

    2012-01-01

    Actinopyga lecanora, a type of sea cucumber commonly known as stone fish with relatively high protein content, was explored as raw material for bioactive peptides production. Six proteolytic enzymes, namely alcalase, papain, pepsin, trypsin, bromelain and flavourzyme were used to hydrolyze A. lecanora at different times and their respective degrees of hydrolysis (DH) were calculated. Subsequently, antibacterial activity of the A. lecanora hydrolysates, against some common pathogenic Gram posi...

  9. Investigation of the antibacterial activity of pioglitazone

    Directory of Open Access Journals (Sweden)

    Alzoubi KH

    2011-09-01

    Full Text Available Majed M Masadeh1, Nizar M Mhaidat2, Sayer I Al-Azzam2, Karem H Alzoubi21Department of Pharmaceutical Technology; 2Department of Clinical Pharmacy, Faculty of Pharmacy, Jordan University of Science and Technology, Irbid, JordanPurpose: To evaluate the antibacterial potential of pioglitazone, a member of the thiazolidinediones class of drugs, against Gram-positive (Streptococcus pneumoniae and Gram-negative (Escherichia coli and Klebsiella pneumoniae bacteria.Methods: Susceptibility testing was done using the antibiotic disk diffusion method and the minimal inhibitory concentration (MIC of pioglitazone was measured according to the broth micro incubation standard method.Results: Pioglitazone induced a dose-dependent antibacterial activity in which the optimal concentration was 80 µM. Furthermore, results indicated that while E. coli was sensitive (MIC = 31.25 ± 3.87 mg/L to pioglitazone-induced cytotoxicity, S. pneumoniae and K. pneumoniae were resistant (MIC = 62.5 ± 3.77 mg/L and MIC = 62.5 ± 4.14 mg/L, respectively. Moreover, pretreatment of bacteria with a suboptimal concentration of pioglitazone (40 µM before adding amoxicillin, cephalexin, co-trimoxazole, or ciprofloxacin enhanced the antibacterial activity of all agents except co-trimoxazole. This enhancing effect was particularly seen against K. pneumoniae.Conclusion: These results indicate the possibility of a new and potentially important pioglitazone effect and the authors’ ongoing studies aim to illustrate the mechanism(s by which this antibacterial effect is induced.Keywords: pioglitazone, susceptibility testing, antibiotics, diabetes 

  10. Similarity analysis, synthesis, and bioassay of antibacterial cyclic peptidomimetics

    Directory of Open Access Journals (Sweden)

    Workalemahu M. Berhanu

    2012-07-01

    Full Text Available The chemical similarity of antibacterial cyclic peptides and peptidomimetics was studied in order to identify new promising cyclic scaffolds. A large descriptor space coupled with cluster analysis was employed to digitize known antibacterial structures and to gauge the potential of new peptidomimetic macrocycles, which were conveniently synthesized by acylbenzotriazole methodology. Some of the synthesized compounds were tested against an array of microorganisms and showed antibacterial activity against Bordetella bronchistepica, Micrococcus luteus, and Salmonella typhimurium.

  11. Similarity analysis, synthesis, and bioassay of antibacterial cyclic peptidomimetics

    Science.gov (United States)

    Berhanu, Workalemahu M; Ibrahim, Mohamed A; Pillai, Girinath G; Oliferenko, Alexander A; Khelashvili, Levan; Jabeen, Farukh; Mirza, Bushra; Ansari, Farzana Latif; ul-Haq, Ihsan; El-Feky, Said A

    2012-01-01

    Summary The chemical similarity of antibacterial cyclic peptides and peptidomimetics was studied in order to identify new promising cyclic scaffolds. A large descriptor space coupled with cluster analysis was employed to digitize known antibacterial structures and to gauge the potential of new peptidomimetic macrocycles, which were conveniently synthesized by acylbenzotriazole methodology. Some of the synthesized compounds were tested against an array of microorganisms and showed antibacterial activity against Bordetella bronchistepica, Micrococcus luteus, and Salmonella typhimurium. PMID:23019443

  12. The antibacterial paradox: essential drugs, effectiveness, and cost.

    OpenAIRE

    Fasehun, F.

    1999-01-01

    The concept proposed by WHO of an essential drugs list that should comprise drugs corresponding to the health needs of the majority of the people has been embraced by countries, which have adapted it to their needs. In this study, the essential antibacterial drug lists of 16 countries chosen from the six WHO regions are reviewed. Most of these countries include 73% of WHO-recommended essential antibacterials on their lists. However, most are lacking reserve antibacterials, and even some main ...

  13. Synthesis, SAR and antibacterial studies on novel chalcone oxazolidinone hybrids.

    Science.gov (United States)

    Selvakumar, N; Kumar, G Sunil; Azhagan, A Malar; Rajulu, G Govinda; Sharma, Shikha; Kumar, M Sitaram; Das, Jagattaran; Iqbal, Javed; Trehan, Sanjay

    2007-04-01

    With an intention to synergise the antibacterial activity of chalcones and oxazolidinones, several hybrid compounds possessing both chalcone and oxazolidinone moieties were synthesized and tested for antibacterial activity. The hybrid molecules containing heterocycles instead of aromatic ring were found to be active. A SAR study with various heterocycles resulted in a lead molecule 20, which was converted to one of the potent antibacterial compounds 27. PMID:17150281

  14. EVALUATION OF ANTIBACTERIAL ACTIVITY OF CAFFEINE

    Directory of Open Access Journals (Sweden)

    Pawar Pruthviraj

    2011-04-01

    Full Text Available The present study was carried out with water soluble portion and pure solvent of the acetone, ethanol, methanol, acetonitrile, water extracts of leaves and leaf buds of Camellia sinensis (green tea, and beans of Coffea arabica (coffee. Caffeine (3,7-dihydro-1, 3,7-trimethyl-1H-purine-2,6-dione was isolated from both plants using a liquid-liquid extraction method, detected on thin layer chromatography (TLC plates in comparison with standard caffeine, which served as a positive control. After performing the gross behavioral study, the Antibacterial activity was evaluated against Gram-negative bacteria included; Escherichia coli, Proteus mirabilis, Klebsiella pneumonia and Pseudomonas aeruginosa Both compounds at a concentration of 2 mg/ml showed similar antibacterial activities against all tested bacteria, except for P. mirabilis, and the highest inhibitory effect was observed against P. aeruginosa using a modified agar diffusion method. The minimal inhibitory concentration (MIC of caffeine was determined using a broth microdilution method in 96 multi-well microtitre plates. MIC values ranged from 65.5 to 250.0 µg/ml for the caffeine isolated from coffee and 65.5 to 500.0 µg/ml for green tea caffeine. Combination results showed additive effects against most pathogenic bacteria especially for P. aeruginosa, using both antibacterial assays.

  15. HostPhinder: A Phage Host Prediction Tool

    DEFF Research Database (Denmark)

    Villarroel, Julia; Kleinheinz, Kortine Annina; Jurtz, Vanessa Isabell;

    2016-01-01

    The current dramatic increase of antibiotic resistant bacteria has revitalised the interest in bacteriophages as alternative antibacterial treatment. Meanwhile, the development of bioinformatics methods for analysing genomic data places high-throughput approaches for phage characterization within...

  16. Towards Identify Selective Antibacterial Peptides Based on Abstracts Meaning.

    Science.gov (United States)

    Barbosa-Santillán, Liliana I; Sánchez-Escobar, Juan J; Calixto-Romo, M Angeles; Barbosa-Santillán, Luis F

    2016-01-01

    We present an Identify Selective Antibacterial Peptides (ISAP) approach based on abstracts meaning. Laboratories and researchers have significantly increased the report of their discoveries related to antibacterial peptides in primary publications. It is important to find antibacterial peptides that have been reported in primary publications because they can produce antibiotics of different generations that attack and destroy the bacteria. Unfortunately, researchers used heterogeneous forms of natural language to describe their discoveries (sometimes without the sequence of the peptides). Thus, we propose that learning the words meaning instead of the antibacterial peptides sequence is possible to identify and predict antibacterial peptides reported in the PubMed engine. The ISAP approach consists of two stages: training and discovering. ISAP founds that the 35% of the abstracts sample had antibacterial peptides and we tested in the updated Antimicrobial Peptide Database 2 (APD2). ISAP predicted that 45% of the abstracts had antibacterial peptides. That is, ISAP found that 810 antibacterial peptides were not classified like that, so they are not reported in APD2. As a result, this new search tool would complement the APD2 with a set of peptides that are candidates to be antibacterial. Finally, 20% of the abstracts were not semantic related to APD2. PMID:27366202

  17. Antibacterial Resistance in African Catfish Aquaculture: a Review

    Directory of Open Access Journals (Sweden)

    Madubuike U. ANYANWU

    2016-03-01

    Full Text Available Antibacterial resistance (AR is currently one of the greatest threats to mankind as it constitutes health crisis. Extensive use of antibacterial agents in human and veterinary medicine, and farm crops have resulted in emergence of antibacterial-resistant organisms in different environmental settings including aquaculture. Antibacterial resistance in aquaculture is a serious global concern because antibacterial resistance genes (ARGs can be transferred easily from aquaculture setting to other ecosystems and the food chain. African catfish (ACF aquaculture has increased at a phenomenal rate through a continuous process of intensification, expansion and diversification. Risk of bacterial diseases has also increased and consequently there is increased use of antibacterial agents for treatment. Antibacterial resistance in ACF aquaculture has huge impact on the food chain and thus represents risk to public and animal health. In “one health” approach of curbing AR, knowledge of the sources, mechanisms and magnitude of AR in ACF aquaculture and its potential impact on the food chain is important in designing and prioritizing monitoring programs that may generate data that would be relevant for performing quantitative risk assessments, implementation of antibacterial stewardship plans, and developing effective treatment strategies for the control of ACF disease and reducing risk to public health. This review provides insight on the sources, mechanisms, prevalence and impact of antibacterial resistance in ACF aquaculture environment, a setting where the impact of AR is neglected or underestimated.

  18. Priming of antiherbivore defensive responses in plants

    Institute of Scientific and Technical Information of China (English)

    Jinwon Kim; Gary W.Felton

    2013-01-01

    Defense priming is defined as increased readiness of defense induction.A growing body of literature indicates that plants (or intact parts of a plant) are primed in anticipation of impending environmental stresses,both biotic and abiotic,and upon the following stimulus,induce defenses more quickly and strongly.For instance,some plants previously exposed to herbivore-inducible plant volatiles (HIPVs) from neighboring plants under herbivore attack show faster or stronger defense activation and enhanced insect resistance when challenged with secondary insect feeding.Research on priming of antiherbivore defense has been limited to the HIPV-mediated mechanism until recently,but significant advances were made in the past three years,including non-HIPV-mediated defense priming,epigenetic modifications as the molecular mechanism of priming,and others.It is timely to consider the advances in research on defense priming in the plantinsect interactions.

  19. Non-antibacterial tetracycline formulations: clinical applications in dentistry and medicine

    Directory of Open Access Journals (Sweden)

    Ying Gu

    2012-10-01

    Full Text Available In 1983, it was first reported that tetracyclines (TCs can modulate the host response, including (but not limited to inhibition of pathologic matrix metalloproteinase (MMP activity, and by mechanisms unrelated to the antibacterial properties of these drugs. Soon thereafter, strategies were developed to generate non-antibacterial formulations (subantimicrobial-dose doxycycline; SDD and compositions (chemically modified tetracyclines; CMTs of TCs as host-modulating drugs to treat periodontal and other inflammatory diseases. This review focuses on the history and rationale for the development of: (a SDD which led to two government-approved medications, one for periodontitis and the other for acne/rosacea and (b CMTs, which led to the identification of the active site of the drugs responsible for MMP inhibition and to studies demonstrating evidence of efficacy of the most potent of these, CMT-3, as an anti-angiogenesis agent in patients with the cancer, Kaposi's sarcoma, and as a potential treatment for a fatal lung disease (acute respiratory distress syndrome; ARDS. In addition, this review discusses a number of clinical studies, some up to 2 years’ duration, demonstrating evidence of safety and efficacy of SDD formulations in humans with oral inflammatory diseases (periodontitis, pemphigoid as well as medical diseases, including rheumatoid arthritis, post-menopausal osteopenia, type II diabetes, cardiovascular diseases, and a rare and fatal lung disease, lymphangioleiomyomatosis.

  20. Web hosting for dummies

    CERN Document Server

    Pollock, Peter

    2013-01-01

    Host your own website or blog with this unique guide If you'd like to make the leap from a hosted environment to a self-hosted service, this book is for you. You may be making the move from casual blogging to professional blogging. Or, you might already be self-hosting, but want a good guide to show you how to get more out of your plan. In simple, easy-to-understand language, this helpful book breaks down all the functions of web hosting for self-hosted users, from setting up new e-mail accounts to backing up and securing your site, analyzing server logs, choosing a platform to ins

  1. Positive selection of HIV host factors and the evolution of lentivirus genes

    OpenAIRE

    Lengauer Thomas; Bożek Katarzyna

    2010-01-01

    Abstract Background Positive selection of host proteins that interact with pathogens can indicate factors relevant for infection and potentially be a measure of pathogen driven evolution. Results Our analysis of 1439 primate genes and 175 lentivirus genomes points to specific host factors of high genetic variability that could account for differences in susceptibility to disease and indicate specific mechanisms of host defense and pathogen adaptation. We find that the largest amount of geneti...

  2. Digenean larvae—the cause and beneficiaries of the changes in host snails’ thermal behavior

    OpenAIRE

    Żbikowska, Elżbieta; Żbikowski, Janusz

    2015-01-01

    Parasite-induced changes in host’s thermal preferences not only can be interpreted as a physiological defense response of the host but also can represent a pathological manifestation of the parasite. Both may become established in host-parasite relationships if they are beneficial for at least one of the counterparts. This study investigates parasite-induced changes in the thermoregulatory behavior of first intermediate hosts of Digenea (i.e. Lymnaea stagnalis and Planorbarius corneus), infec...

  3. Host Adaptation Is Contingent upon the Infection Route Taken by Pathogens

    OpenAIRE

    Martins, Nelson E.; Faria, Vitor G.; Teixeira, Luis; Magalhães, Sara; Sucena, Élio

    2013-01-01

    Author Summary Pathogens enter their hosts through several routes, the most common being ingestion (oral infection) and breaches in the cuticle (systemic infection). Several studies have shown that these infection routes strongly affect the evolution of pathogen virulence, though little attention has been given to the role of host evolution in this process. Here, we study the effect of infection route on the evolution of host defenses, using Drosophila melanogaster and its natural pathogen Ps...

  4. FUETAP concrete - an alternative radioactive waste host

    International Nuclear Information System (INIS)

    These tailored autoclaved concretes (FUETAP concentrates) offer a number of advantages as hosts for a wide variety of radioactive wastes. They are formed at low temperatures and pressures (1000C and 0.1 MPa) from readily available raw materials and require no new processing technology. The extreme latitude in concrete formulations ensures the acceptance of the gamut of waste materials. The leachability of nuclides from the resulting ceramic-like concretes is quite low with essentially no prospect of pressure build-up from long-term self-irradiation in the final storage containers. The solids are thermally stable up to at least 9000C. Additional studies are in progress to verify that FUETAP concretes are acceptable alternative waste hosts for defense, TRU, and commercial high-level radioactive waste. (orig.)

  5. SQL Injection Attacks and Defense

    CERN Document Server

    Clarke, Justin

    2012-01-01

    SQL Injection Attacks and Defense, First Edition: Winner of the Best Book Bejtlich Read Award "SQL injection is probably the number one problem for any server-side application, and this book unequaled in its coverage." -Richard Bejtlich, Tao Security blog SQL injection represents one of the most dangerous and well-known, yet misunderstood, security vulnerabilities on the Internet, largely because there is no central repository of information available for penetration testers, IT security consultants and practitioners, and web/software developers to turn to for help. SQL Injection Att

  6. Cyber defense and situational awareness

    CERN Document Server

    Kott, Alexander; Erbacher, Robert F

    2015-01-01

    This book is the first publication to give a comprehensive, structured treatment to the important topic of situational awareness in cyber defense. It presents the subject in a logical, consistent, continuous discourse, covering key topics such as formation of cyber situational awareness, visualization and human factors, automated learning and inference, use of ontologies and metrics, predicting and assessing impact of cyber attacks, and achieving resilience of cyber and physical mission. Chapters include case studies, recent research results and practical insights described specifically for th

  7. Territorial Defense, Education, and Interculturalism

    Directory of Open Access Journals (Sweden)

    Claudia Patricia Sierra Pardo

    2011-10-01

    Full Text Available The article carries out a series of reflections regarding the social and economic conditions in which the cultivation of oil palm affected the Bajo Atrato region of the Department of Chocó at the end of the nineteen nineties. It also discusses the actions carried out by communities, companies, and organizations in solidarity with the region’s cause, since these expressions make it possible to understand the role of organization and education in territorial defense processes. Finally, the article examines the different tensions, struggles, challenges, and contradictions inherent to these types of processes.

  8. Application of SYNROC to high-level defense wastes

    International Nuclear Information System (INIS)

    The SYNROC method for immobilization of high-level nuclear reactor wastes is currently being applied to US defense wastes in tank storage at Savannah River, South Carolina. The minerals zirconolite, perovskite, and hollandite are used in SYNROC D formulations to immobilize fission products and actinides that comprise up to 10% of defense waste sludges and coexisting solutions. Additional phases in SYNROC D are nepheline, the host phase for sodium; and spinel, the host for excess aluminum and iron. Up to 70 wt % of calcined sludge can be incorporated with 30 wt % of SYNROC additives to produce a waste form consisting of 10% nepheline, 30% spinel, and approximately 20% each of the radioactive waste-bearing phases. Urea coprecipitation and spray drying/calcining methods have been used in the laboratory to produce homogeneous, reactive ceramic powders. Hot pressing and sintering at temperatures from 1000 to 11000C result in waste form products with greater than 97% of theoretical density. Hot isostatic pressing has recently been implemented as a processing alternative. Characterization of waste-form mineralogy has been done by means of XRD, SEM, and electron microprobe. Leaching of SYNROC D samples is currently being carried out. Assessment of radiation damage effects and physical properties of SYNROC D will commence in FY 81

  9. Application of SYNROC to high-level defense wastes

    International Nuclear Information System (INIS)

    The SYNROC method for immobilization of high-level nuclear reactor wastes is currently being applied to US defense wastes in tank storage at Savannah River, South Carolina. The minerals zirconolite, perovskite, and hollandite are used in SYNROC D formulations to immobilize fission products and actinides that comprise up to 10% of defense waste sludges and coexisting solutions. Additional phase in SYNROC D are nepheline, the host phase for sodium; and spinel, the host for excess aluminum and iron. Up to 70 wt % of calcined sludge can be incorporated with 30 wt % of SYNROC additives to produce a waste form consisting of 10% nepheline, 30% spinel, and approximately 20% each of the radioactive waste-bearing phases. Urea coprecipitation and spray drying/calcining methods have been used in the laboratory to produce homogeneous, reactive ceramic powders. Hot pressing and sintering at temperatures from 1000 to 11000C result in waste form products with greater than 97% of theoretical density. Hot isostatic pressing has recently been implemented as a processing alternative. Characterization of waste-form mineralogy has been done by means of XRD, SEM, and electron microprobe. Leaching of SYNROC D samples is currently being carried out. Assessment of radiation damage effects and physical properties of SYNROC D will commence in FY81

  10. A novel role for β2-microglobulin: a precursor of antibacterial chemokine in respiratory epithelial cells.

    Science.gov (United States)

    Chiou, Shean-Jaw; Wang, Chan-Chi; Tseng, Yan-Shen; Lee, Yen-Jung; Chen, Shih-Chieh; Chou, Chi-Hsien; Chuang, Lea-Yea; Hong, Yi-Ren; Lu, Chi-Yu; Chiu, Chien-Chih; Chignard, Michel

    2016-01-01

    We analyzed a panel of cationic molecules secreted in the culture medium of human respiratory epithelial cells (REC) upon activation by IL-1β and different pathogen-associated molecular patterns. A 9 kDa fragment derived from β2-microglobulin (B2M) was identified and named shed 9 kDa B2M (sB2M-9). The primary structure of sB2M-9 was revealed to increase its pI value that potentially could play an important role in innate defense. sB2M-9 exhibits antibacterial activity against Gram positive Staphylococcus aureus (SA) but not against Gram negative Klebsiella pneumonia (KP). Upon its binding to SA, sB2M-9 induces clumps, a phenomenon not observed with B2M. Migration of THP-1 monocytes exposed to SA clumps was significantly greater than that to SA without clumps. sB2M-9 binds to SA, more likely as a chemokine, to facilitate THP-1 migration. As a whole, we demonstrated that REC release a novel chemokine with antibacterial activity that is shed from B2M to facilitate THP-1 migration. PMID:27503241

  11. Enhancing antibacterial activity of surface-grafted chitosan with immobilized lysozyme on bioinspired stainless steel substrates.

    Science.gov (United States)

    Yuan, Shaojun; Yin, Jia; Jiang, Wei; Liang, Bin; Pehkonen, S O; Choong, Cleo

    2013-06-01

    Bacterial infections have been widely recognized as a major cause of the failure of medical implants and devices. One promising strategy to reduce the incidence of infections is to impart the material surfaces with bactericidal function for inhibiting bacterial adhesion and biofilm formation. In this study, stainless steel (SS) surface was first activated by a biomimetic dopamine anchor to provide active amino groups, followed by covalently immobilizing chitosan (CS) with glutaraldehyde (GA) as a bifunctional linker. Hen egg white lysozyme, a natural defensive enzyme, was finally conjugated to the grafted chitosan to enhance biocidal functionality. The antibacterial assay results demonstrated substantial enhancement in bactericidal efficiency against Staphylococcus aureus (S. aureus) on the lysozyme-immobilized SS substrates under the neutral pH conditions as compared to the chitosan-grafted SS substrates. With the inherent advantages of robust anchoring ability of dopamine and specific functionality of lysozyme, the metallic substrates can be readily tailored with antibacterial property to combat biomaterial-centered infection for potential biomedical applications. PMID:23434686

  12. Analysis of gene expression from the Wolbachia genome of a filarial nematode supports both metabolic and defensive roles within the symbiosis.

    Science.gov (United States)

    Darby, Alistair C; Armstrong, Stuart D; Bah, Germanus S; Kaur, Gaganjot; Hughes, Margaret A; Kay, Suzanne M; Koldkjær, Pia; Rainbow, Lucille; Radford, Alan D; Blaxter, Mark L; Tanya, Vincent N; Trees, Alexander J; Cordaux, Richard; Wastling, Jonathan M; Makepeace, Benjamin L

    2012-12-01

    The α-proteobacterium Wolbachia is probably the most prevalent, vertically transmitted symbiont on Earth. In contrast with its wide distribution in arthropods, Wolbachia is restricted to one family of animal-parasitic nematodes, the Onchocercidae. This includes filarial pathogens such as Onchocerca volvulus, the cause of human onchocerciasis, or river blindness. The symbiosis between filariae and Wolbachia is obligate, although the basis of this dependency is not fully understood. Previous studies suggested that Wolbachia may provision metabolites (e.g., haem, riboflavin, and nucleotides) and/or contribute to immune defense. Importantly, Wolbachia is restricted to somatic tissues in adult male worms, whereas females also harbor bacteria in the germline. We sought to characterize the nature of the symbiosis between Wolbachia and O. ochengi, a bovine parasite representing the closest relative of O. volvulus. First, we sequenced the complete genome of Wolbachia strain wOo, which revealed an inability to synthesize riboflavin de novo. Using RNA-seq, we also generated endobacterial transcriptomes from male soma and female germline. In the soma, transcripts for membrane transport and respiration were up-regulated, while the gonad exhibited enrichment for DNA replication and translation. The most abundant Wolbachia proteins, as determined by geLC-MS, included ligands for mammalian Toll-like receptors. Enzymes involved in nucleotide synthesis were dominant among metabolism-related proteins, whereas the haem biosynthetic pathway was poorly represented. We conclude that Wolbachia may have a mitochondrion-like function in the soma, generating ATP for its host. Moreover, the abundance of immunogenic proteins in wOo suggests a role in diverting the immune system toward an ineffective antibacterial response. PMID:22919073

  13. Analysis and design of a cooperative weapon assignment module for advanced battle manager of a ballistic missile defense system

    OpenAIRE

    Brown, Willie D.

    2006-01-01

    The United States is in the midst of an ambitious effort to build and deploy a wide range of ballistic missile defense systems. These ballistic missile defense systems will be effective against a host of current and postulated threats from ballistic missiles. In this thesis study, we explore the process of enhancing the effectiveness of weapon assignment for a system of systems. First, analysis of information is drawn from current proposed system of the ABM and its construction from the ...

  14. Defense mutualisms enhance plant diversification.

    Science.gov (United States)

    Weber, Marjorie G; Agrawal, Anurag A

    2014-11-18

    The ability of plants to form mutualistic relationships with animal defenders has long been suspected to influence their evolutionary success, both by decreasing extinction risk and by increasing opportunity for speciation through an expanded realized niche. Nonetheless, the hypothesis that defense mutualisms consistently enhance plant diversification across lineages has not been well tested due to a lack of phenotypic and phylogenetic information. Using a global analysis, we show that the >100 vascular plant families in which species have evolved extrafloral nectaries (EFNs), sugar-secreting organs that recruit arthropod mutualists, have twofold higher diversification rates than families that lack species with EFNs. Zooming in on six distantly related plant clades, trait-dependent diversification models confirmed the tendency for lineages with EFNs to display increased rates of diversification. These results were consistent across methodological approaches. Inference using reversible-jump Markov chain Monte Carlo (MCMC) to model the placement and number of rate shifts revealed that high net diversification rates in EFN clades were driven by an increased number of positive rate shifts following EFN evolution compared with sister clades, suggesting that EFNs may be indirect facilitators of diversification. Our replicated analysis indicates that defense mutualisms put lineages on a path toward increased diversification rates within and between clades, and is concordant with the hypothesis that mutualistic interactions with animals can have an impact on deep macroevolutionary patterns and enhance plant diversity. PMID:25349406

  15. For a NATO defensive deterrent

    International Nuclear Information System (INIS)

    This paper proposes that NATO should adopt, in a gradual and orderly fashion, a grand strategy and accompanying posture distinctly different from its present one. The strategy the author recommends has variously been termed non-provocative defence, defence-only defence, or defensive deterrence, employs the latter term here. By it the author means a militarily sound strategy relying solely on conventional weapons so long as the enemy uses only conventional weapons, and a posture that is unambiguously capable only of defence. Secure, second-strike nuclear forces would be retained for deterrence of any nuclear use by the opponent. This goal is consistent with the goal stated in Frank Barnaby's companion paper in this volume; here however the author lays the emphasis on political and politico-military rationales for a defensive deterrent. The paper begins with two brief arguments why a shift in NATO strategy is needed, advances some distinctions among the possible alternatives, and then presents some seven rationales for its recommended policy

  16. Application of Defense Technology Commonly Used in Boxing Match

    Institute of Scientific and Technical Information of China (English)

    Zhixiao Li[1; Jianjun Liu[2

    2015-01-01

    Boxing defense technology is a kind of techniques to prevent the opponent from attacking successfully. Boxing is a kind of sports that needs close cooperation between attack and defense. Attack is used for defense, where there is no attack, there will be no defense, and vice versa. Defense technology is the foundation of attack technology, therefore, defense is of vital importance in boxing match.

  17. Turnabout Is Fair Play: Herbivory-Induced Plant Chitinases Excreted in Fall Armyworm Frass Suppress Herbivore Defenses in Maize.

    Science.gov (United States)

    Ray, Swayamjit; Alves, Patrick C M S; Ahmad, Imtiaz; Gaffoor, Iffa; Acevedo, Flor E; Peiffer, Michelle; Jin, Shan; Han, Yang; Shakeel, Samina; Felton, Gary W; Luthe, Dawn S

    2016-05-01

    The perception of herbivory by plants is known to be triggered by the deposition of insect-derived factors such as saliva and oral secretions, oviposition materials, and even feces. Such insect-derived materials harbor chemical cues that may elicit herbivore and/or pathogen-induced defenses in plants. Several insect-derived molecules that trigger herbivore-induced defenses in plants are known; however, insect-derived molecules suppressing them are largely unknown. In this study, we identified two plant chitinases from fall armyworm (Spodoptera frugiperda) larval frass that suppress herbivore defenses while simultaneously inducing pathogen defenses in maize (Zea mays). Fall armyworm larvae feed in enclosed whorls of maize plants, where frass accumulates over extended periods of time in close proximity to damaged leaf tissue. Our study shows that maize chitinases, Pr4 and Endochitinase A, are induced during herbivory and subsequently deposited on the host with the feces. These plant chitinases mediate the suppression of herbivore-induced defenses, thereby increasing the performance of the insect on the host. Pr4 and Endochitinase A also trigger the antagonistic pathogen defense pathway in maize and suppress fungal pathogen growth on maize leaves. Frass-induced suppression of herbivore defenses by deposition of the plant-derived chitinases Pr4 and Endochitinase A is a unique way an insect can co-opt the plant's defense proteins for its own benefit. It is also a phenomenon unlike the induction of herbivore defenses by insect oral secretions in most host-herbivore systems. PMID:26979328

  18. Two Novel Antibacterial Flavonoids from Myrsine Africana L.

    Institute of Scientific and Technical Information of China (English)

    KANG,Lu; ZHOU,Jian-Xia; SHEN,Zheng-Wu

    2007-01-01

    Two novel flavonoids, myrsininone A (1), an isoflavone and myrsininone B (2), a flavanone, with very strong antibacterial activities, were isolated from the stems of Myrsine africana L. Their structures were elucidated by extensive spectroscopic analyses. The antibacterial activities were determined by modified Resazuric MIC methods.

  19. Cationic amphiphilic non-hemolytic polyacrylates with superior antibacterial activity.

    Science.gov (United States)

    Punia, Ashish; He, Edward; Lee, Kevin; Banerjee, Probal; Yang, Nan-Loh

    2014-07-01

    Acrylic copolymers with appropriate compositions of counits having cationic charge with 2-carbon and 6-carbon spacer arms can show superior antibacterial activities with concomitant very low hemolytic effect. These amphiphilic copolymers represent one of the most promising synthetic polymer antibacterial systems reported. PMID:24854366

  20. Antibacterial activity of mushroom Osmoporus odoratus

    OpenAIRE

    Sivakumar R; Vetrichelvan T; Rajendran N; Devi M; Sundaramoorthi K; Shankar ASK; Shanmugam S

    2006-01-01

    The petroleum ether, chloroform, acetone and water extracts of mushroom Osmoporus odoratus were selected for examine the antibacterial activity against Staphylococcus aureus, Streptococcus pyogenes, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa by disc diffusion method using Muller Hinton agar media. And the extracts were compared with that of standard ampicillin (30 µg) and chloramphenicol (30 µg). The water extract alone showed antibacterial activity aga...

  1. Facilitating Antibacterial Drug Development in a Time of Great Need.

    Science.gov (United States)

    Cox, Edward; Cavaleri, Marco; Eichler, Hans-Georg; Woodcock, Janet; Borio, Luciana

    2016-08-15

    The continued development of new antibacterial drugs is critical to meet patient and public health needs. In this editorial, authors from the US Food and Drug Administration and European Medicines Agency reflect on the role of public-private partnerships and the development of clinical trials networks as agents to guide and perform quality studies of antibacterial drugs. PMID:27481949

  2. Soluble Eggshell Mebrane Protein:Antibacterial Property and Biodegradability

    Institute of Scientific and Technical Information of China (English)

    YI Feng; YU Jian; LI Qiang; GUO Zhaoxia

    2007-01-01

    The antibacterial property and biodegradability of soluble eggshell membrane protein (SEP)are reported. Unlike the natural eggshell membrane (ESM), SEP does not possess antibacterial property against E.coli. The biodegradation tests with trypsin show that both ESM and SEP are biodegradable.

  3. Protein Interactions in Genome Maintenance as Novel Antibacterial Targets

    OpenAIRE

    Marceau, Aimee H; Bernstein, Douglas A.; Walsh, Brian W.; Shapiro, Walker; Simmons, Lyle A.; Keck, James L.

    2013-01-01

    Antibacterial compounds typically act by directly inhibiting essential bacterial enzyme activities. Although this general mechanism of action has fueled traditional antibiotic discovery efforts for decades, new antibiotic development has not kept pace with the emergence of drug resistant bacterial strains. These limitations have severely restricted the therapeutic tools available for treating bacterial infections. Here we test an alternative antibacterial lead-compound identification strategy...

  4. In Vitro Antibacterial Activity of Ibuprofen and Acetaminophen

    OpenAIRE

    AL-Janabi, Ali Abdul Hussein S.

    2010-01-01

    Background: Ibuprofen and acetaminophen are common chemical agents that have anti-inflammatory, antipyretic, and analgesic activity. Aims: To detect any potential antibacterial effects of ibuprofen and acetaminophen on pathogenic bacteria. Materials and methods: Ibuprofen and acetaminophen were tested for antibacterial activity against seven isolates of bacteria including gram positive bacteria (Staphylococci aureus and Bacillus subtilis) and gram negative bacteria (E. coli, Enterobacter a...

  5. Defensive complexity in antagonistic coevolution

    OpenAIRE

    Chastain, Erick; Antia, Rustom; Bergstrom, Carl T.

    2012-01-01

    One strategy for winning a coevolutionary struggle is to evolve rapidly. Most of the literature on host-pathogen coevolution focuses on this phenomenon, and looks for consequent evidence of coevolutionary arms races. An alternative strategy, less often considered in the literature, is to deter rapid evolutionary change by the opponent. To study how this can be done, we construct an evolutionary game between a controller that must process information, and an adversary that can tamper with this...

  6. Parasitic wasp responses to symbiont-based defense in aphids

    Directory of Open Access Journals (Sweden)

    Oliver Kerry M

    2012-02-01

    Full Text Available Abstract Background Recent findings indicate that several insect lineages receive protection against particular natural enemies through infection with heritable symbionts, but little is yet known about whether enemies are able to discriminate and respond to symbiont-based defense. The pea aphid, Acyrthosiphon pisum, receives protection against the parasitic wasp, Aphidius ervi, when infected with the bacterial symbiont Hamiltonella defensa and its associated bacteriophage APSE (Acyrthosiphon pisum secondary endosymbiont. Internally developing parasitoid wasps, such as A. ervi, use maternal and embryonic factors to create an environment suitable for developing wasps. If more than one parasitoid egg is deposited into a single aphid host (superparasitism, then additional complements of these factors may contribute to the successful development of the single parasitoid that emerges. Results We performed experiments to determine if superparasitism is a tactic allowing wasps to overcome symbiont-mediated defense. We found that the deposition of two eggs into symbiont-protected aphids significantly increased rates of successful parasitism relative to singly parasitized aphids. We then conducted behavioral assays to determine whether A. ervi selectively superparasitizes H. defensa-infected aphids. In choice tests, we found that A. ervi tends to deposit a single egg in uninfected aphids, but two or more eggs in H. defensa-infected aphids, indicating that oviposition choices may be largely determined by infection status. Finally, we identified differences in the quantity of the trans-β-farnesene, the major component of aphid alarm pheromone, between H. defensa-infected and uninfected aphids, which may form the basis for discrimination. Conclusions Here we show that the parasitic wasp A. ervi discriminates among symbiont-infected and uninfected aphids, and changes its oviposition behavior in a way that increases the likelihood of overcoming symbiont

  7. Self-organized defensive behavior in honeybees

    OpenAIRE

    Millor, J.; Pham-Delegue, M; Deneubourg, J. L.; Camazine, S

    1999-01-01

    We investigated the defensive behavior of honeybees under controlled experimental conditions. During an attack on two identical targets, the spatial distribution of stings varied as a function of the total number of stings, evincing the classic “pitchfork bifurcation” phenomenon of nonlinear dynamics. The experimental results support a model of defensive behavior based on a self-organizing mechanism. The model helps to explain several of the characteristic features of the honeybee defensive r...

  8. Defense spending and interregional labor migration.

    Science.gov (United States)

    Ellis, M; Barff, R; Markusen, A R

    1993-04-01

    The impact of defense-related industry on labor migration within the United States is analyzed using census data for the period 1975-1980. The results "suggest that workers follow jobs in the defense industry, rather than vice versa, and indicate that a process of defense-related regional labor pool formation, amplified by interstate migration, adds to the volume of interregional labor flows." PMID:12286235

  9. Mechanisms of plant defense against insect herbivores

    OpenAIRE

    War, Abdul Rashid; Paulraj, Michael Gabriel; Ahmad, Tariq; BUHROO, Abdul Ahad; Hussain, Barkat; Ignacimuthu, Savarimuthu; Sharma, Hari Chand

    2012-01-01

    Plants respond to herbivory through various morphological, biochemicals, and molecular mechanisms to counter/offset the effects of herbivore attack. The biochemical mechanisms of defense against the herbivores are wide-ranging, highly dynamic, and are mediated both by direct and indirect defenses. The defensive compounds are either produced constitutively or in response to plant damage, and affect feeding, growth, and survival of herbivores. In addition, plants also release volatile organic c...

  10. THE DEFENSE PLANNING SYSTEMS AND THEIR IMPLICATIONS

    Directory of Open Access Journals (Sweden)

    Laszlo STICZ

    2010-01-01

    Full Text Available Defense planning in the Alliance is a fundamental element of the arrangements which enable its member countries to enjoy the crucial political, military and resource advantages of collective defense and other common military efforts to enhance security and stability. In this respect, the aim of this paper is to outline the role of the Armed Forces and the specific processes aiming to achieve the ultimate goal of a nation regarding national security, with focus on defense planning and the PDPS.

  11. Defense Transuranic Waste Program Strategy Document

    International Nuclear Information System (INIS)

    The Defense Transuranic Waste Program (DTWP) Strategy Document presents the general strategy for managing transuranic (TRU) waste materials generated during defense and research activities regulated by the US Department of Energy. The Strategy Document includes discussion of objectives and activities relating to the entire Defense Transuranic Waste Program. However, the primary focus is on the specific management responsibilities of the Transuranic Waste Lead Organization (TLO). The document also includes an updated summary of progress on TLO-managed activities over the past year

  12. In Vitro Antibacterial Activity of Essential Oils against Streptococcus pyogenes.

    Science.gov (United States)

    Sfeir, Julien; Lefrançois, Corinne; Baudoux, Dominique; Derbré, Séverine; Licznar, Patricia

    2013-01-01

    Streptococcus pyogenes plays an important role in the pathogenesis of tonsillitis. The present study was conducted to evaluate the in vitro antibacterial activities of 18 essential oils chemotypes from aromatic medicinal plants against S. pyogenes. Antibacterial activity of essential oils was investigated using disc diffusion method. Minimum Inhibitory Concentration of essential oils showing an important antibacterial activity was measured using broth dilution method. Out of 18 essential oils tested, 14 showed antibacterial activity against S. pyogenes. Among them Cinnamomum verum, Cymbopogon citratus, Thymus vulgaris CT thymol, Origanum compactum, and Satureja montana essential oils exhibited significant antibacterial activity. The in vitro results reported here suggest that, for patients suffering from bacterial throat infections, if aromatherapy is used, these essential oils, considered as potential antimicrobial agents, should be preferred. PMID:23662123

  13. The Antibacterial Applications of Graphene and Its Derivatives.

    Science.gov (United States)

    Shi, Lin; Chen, Jiongrun; Teng, Lijing; Wang, Lin; Zhu, Guanglin; Liu, Sa; Luo, Zhengtang; Shi, Xuetao; Wang, Yingjun; Ren, Li

    2016-08-01

    Graphene materials have unique structures and outstanding thermal, optical, mechanical and electronic properties. In the last decade, these materials have attracted substantial interest in the field of nanomaterials, with applications ranging from biosensors to biomedicine. Among these applications, great advances have been made in the field of antibacterial agents. Here, recent advancements in the use of graphene and its derivatives as antibacterial agents are reviewed. Graphene is used in three forms: the pristine form; mixed with other antibacterial agents, such as Ag and chitosan; or with a base material, such as poly (N-vinylcarbazole) (PVK) and poly (lactic acid) (PLA). The main mechanisms proposed to explain the antibacterial behaviors of graphene and its derivatives are the membrane stress hypothesis, the oxidative stress hypothesis, the entrapment hypothesis, the electron transfer hypothesis and the photothermal hypothesis. This review describes contributions to improving these promising materials for antibacterial applications. PMID:27389848

  14. Synthesis and antibacterial evaluation of macrocyclic diarylheptanoid derivatives.

    Science.gov (United States)

    Lin, Hao; Bruhn, David F; Maddox, Marcus M; Singh, Aman P; Lee, Richard E; Sun, Dianqing

    2016-08-15

    Bacterial infections, caused by Mycobacterium tuberculosis and other problematic bacterial pathogens, continue to pose a significant threat to global public health. As such, new chemotype antibacterial agents are desperately needed to fuel and strengthen the antibacterial drug discovery and development pipeline. As part of our antibacterial research program to develop natural product-inspired new antibacterial agents, here we report synthesis, antibacterial evaluation, and structure-activity relationship studies of an extended chemical library of macrocyclic diarylheptanoids with diverse amine, amide, urea, and sulfonamide functionalities. Results of this study have produced macrocyclic geranylamine and 4-fluorophenethylamine substituted derivatives, exhibiting moderate to good activity against M. tuberculosis and selected Gram-positive bacterial pathogens. PMID:27406794

  15. Future prospects of antibacterial metal nanoparticles as enzyme inhibitor.

    Science.gov (United States)

    Ahmed, Khan Behlol Ayaz; Raman, Thiagarajan; Veerappan, Anbazhagan

    2016-11-01

    Nanoparticles are being widely used as antibacterial agents with metal nanoparticles emerging as the most efficient antibacterial agents. There have been many studies which have reported the mechanism of antibacterial activity of nanoparticles on bacteria. In this review we aim to emphasize on all the possible mechanisms which are involved in the antibacterial activity of nanoparticles and also to understand their mode of action and role as bacterial enzyme inhibitor by comparing their antibacterial mechanism to that of antibiotics with enzyme inhibition as a major mechanism. With the emergence of widespread antibiotic resistance, nanoparticles offer a better alternative to our conventional arsenal of antibiotics. Once the biological safety of these nanoparticles is addressed, these nanoparticles can be of great medical importance in our fight against bacterial infections. PMID:27524096

  16. In Vitro Antibacterial Activity of Essential Oils against Streptococcus pyogenes

    Directory of Open Access Journals (Sweden)

    Julien Sfeir

    2013-01-01

    Full Text Available Streptococcus pyogenes plays an important role in the pathogenesis of tonsillitis. The present study was conducted to evaluate the in vitro antibacterial activities of 18 essential oils chemotypes from aromatic medicinal plants against S. pyogenes. Antibacterial activity of essential oils was investigated using disc diffusion method. Minimum Inhibitory Concentration of essential oils showing an important antibacterial activity was measured using broth dilution method. Out of 18 essential oils tested, 14 showed antibacterial activity against S. pyogenes. Among them Cinnamomum verum, Cymbopogon citratus, Thymus vulgaris CT thymol, Origanum compactum, and Satureja montana essential oils exhibited significant antibacterial activity. The in vitro results reported here suggest that, for patients suffering from bacterial throat infections, if aromatherapy is used, these essential oils, considered as potential antimicrobial agents, should be preferred.

  17. Antibacterial biodegradable Mg-Ag alloys

    OpenAIRE

    D Tie; F Feyerabend; W-D Müller; Schade, R; Liefeith, K; KU Kainer; Willumeit, R.

    2013-01-01

    The use of magnesium alloys as degradable metals for biomedical applications is a topic of ongoing research and the demand for multifunctional materials is increasing. Hence, binary Mg-Ag alloys were designed as implant materials to combine the favourable properties of magnesium with the well-known antibacterial property of silver. In this study, three Mg-Ag alloys, Mg2Ag, Mg4Ag and Mg6Ag that contain 1.87 %, 3.82 % and 6.00 % silver by weight, respectively, were cast and processed with solut...

  18. Antibacterial Mg-Ag biodegradable alloys

    OpenAIRE

    Tie, Di

    2013-01-01

    The use of magnesium alloys as degradable metals for biomedical applications is topic of ongoing research. As a further aspect, the demand for multifunctional materials is increasing. Hence, binary Mg-Ag alloys were designed to combine the favourable properties of magnesium with the wellknown antibacterial property of silver. In this study, three Mg-Ag alloys, Mg2Ag, Mg4Ag and Mg6Ag which contain 1.87%, 3.82% and 6.00% silver by weight respectively were casted and processed with solution and ...

  19. Antioxidant and antibacterial properties of capsaicine microemulsions

    OpenAIRE

    CRISTIAN DIMA; GIGI COMAN; MIHAELA COTÂRLEŢ; PETRU ALEXE; ŞTEFAN DIMA

    2013-01-01

    The aim of this study was to prepare capsaicin microemulsions and to assess their antioxidant and antibacterial properties. Pseudoternare phase diagrams were made and were highlighted O/W/S/CoS weight ratios corresponding to microemulsion states. The oil phase (O) was soybean oil and for the aqueous phase (W) was used a mixture of water and glycerol in a ratio of 4:1 (wt/wt). As a surfactant (S) was used Tween 40 and cosurfactant (CoS) was ethanol in the mass ratio S:CoS = 2:1. Viscosimetr...

  20. Chemical and antibacterial constituents of Skimmia anquetelia.

    Science.gov (United States)

    Sharma, Rajni Kant; Negi, Devendra Singh; Gibbons, Simon; Otsuka, Hideaki

    2008-02-01

    Investigation of the leaves of Skimmia anquetelia (Rutaceae) led to the isolation of a new coumarin glucoside 7,8-dihdroxy-6-[3'-beta- D-glucopyranosyloxy-2'(xi)-hydroxy-3'-methylbutyl]-coumarin ( 1) together with five known coumarins: 6-(2,3-dihydroxy-3-methylbutyl)-7-methoxycoumarin ( 2), skimmin ( 3), osthol ( 4), esculetin ( 5) and scopuletin ( 6). The antibacterial activity of compounds 1 and 3 was also investigated against the plant bacterial pathogens Agrobacterium tumifaciens, Pseudomonas syringae and Pactobacterium carotovorum. Structures were determined on the basis of analyses of spectral evidence including 1D, 2 D NMR (COSY, HMQC, HMBC and NOESY) and mass spectroscopy. PMID:18240101

  1. Synthesis and Antibacterial Activity of Thiophenes

    Directory of Open Access Journals (Sweden)

    Wedad M. Al-Adiwish

    2012-01-01

    Full Text Available 2-[Bis(methylthiomethylene]propanedinitrile 1a reacted in one-pot successively with piperidine, sodium sulfide, chloroacetonitrile, and potassium carbonate to afford 3-amino-5-(1-piperidinyl-2,4-thiophenedicarbonitrile 2a. Similar reaction using the last three reagents with ethyl 2-cyano-3,3-bis(methylthioacrylate 1b produced ethyl 4-amino-5-cyano-2-(methylthiothiophene-3-carboxylate 2b. The synthesized compounds were characterized by using FT-IR, 1H-NMR, 13C-NMR, and mass spectral data. Antibacterial activities of the synthesized compounds are also reported.

  2. Detection of the antibacterial activity of chitosan

    OpenAIRE

    Mayer, Gerd; Claußen, Tatjana; Heisig, Peter

    2007-01-01

    Using three bacterial strains the antibacterial activity of Chitoskin®, a chitosan-containing wound-dressing, was investigated by determining the viable bacterial cell count in liquid cultures in the absence and presence of Chitoskin®. Results were compared to those obtained for cellulose and silver-laminated cellulose.While the pure cellulose wound-dressing had no impact on the bacterial growth, Chitoskin® and, to an even greater extend, silver-laminated cellulose reduced the viable cell cou...

  3. Low power unattended defense reactor

    International Nuclear Information System (INIS)

    A small, low power, passive, nuclear reactor electric power supply has been designed for unattended defense applications. Through innovative utilization of existing proven technologies and components, a highly reliable, walk-away safe design has been obtained. Operating at a thermal power level of 200 kWt, the reactor uses low enrichment uranium fuel in a graphite block core to generate heat that is transferred through heat pipes to a thermoelectric (TE) converter. Waste heat is removed from the TEs by circulation of ambient air. Because such a power supply offers the promise of minimal operation and maintenance (O and M) costs as well as no fuel logistics, it is particularly attractive for remote, unattended applications such as the North Warning System

  4. Civil defense should be mandatory

    International Nuclear Information System (INIS)

    In this paper, the author exposes myths about the effects of nuclear weapons so that the U.S. can begin the necessary task of a mandatory civil defense program. An all-out nuclear war between Russia and the United States would be the worst catastrophe in history, a tragedy so huge it is difficult to comprehend. Even so, it would be far from the end of human life on earth. The dangers from nuclear weapons have been distorted and exaggerated for varied reasons. These exaggerations have become demoralizing myths, believed by millions of Americans. The author has found that many people see no sense in talking about details of survival skills. Only after they have begun to question the truth of these myths do they become interested, under normal peacetime conditions, in acquiring nuclear war survival skills. The author examines the most harmful of the myths about nuclear war dangers, along with some of the grim facts

  5. Department of Defense, Deployment Health Clinical Center

    Science.gov (United States)

    ... Psychological Health Policy Library Search psychological health and deployment-related policies and directives, including service-specific policies, published by the Defense Department, Congress ...

  6. Defense styles in Intermittent Explosive Disorder.

    Science.gov (United States)

    Puhalla, Alexander A; McCloskey, Michael S; Brickman, Lauren J; Fauber, Robert; Coccaro, Emil F

    2016-04-30

    The overreliance on immature and/or neurotic defense mechanisms, as opposed to more mature defensive functioning has been linked to several psychiatric disorders. However, to date, the role of defense styles among individuals with Intermittent Explosive Disorder (IED) has not been examined. Given that individuals with IED display difficulties controlling their anger and aggression, one might expect these individuals to exhibit more immature and less mature defense styles. The current study compared participants with IED to a personality disorder (PD) comparison group, as well as to healthy volunteers (HV) on the Defense Style Questionnaire, a self-report measure that assesses the extent to which individuals endorse using mature, immature, and neurotic defense styles. Subjects with IED had significantly higher scores than both comparison groups on immature defense styles and exhibited lower scores on mature defense mechanisms. Hierarchical regression of significant defense style subscales showed that higher levels of acting out and lower levels of sublimation uniquely discriminated participants with IED from the PD and HV comparison groups. PMID:27086223

  7. Bacteria-host relationship: ubiquitin ligases as weapons of invasion.

    Science.gov (United States)

    Maculins, Timurs; Fiskin, Evgenij; Bhogaraju, Sagar; Dikic, Ivan

    2016-04-01

    Eukaryotic cells utilize the ubiquitin (Ub) system for maintaining a balanced functioning of cellular pathways. Although the Ub system is exclusive to eukaryotes, prokaryotic bacteria have developed an armory of Ub ligase enzymes that are capable of employing the Ub systems of various hosts, ranging from plant to animal cells. These enzymes have been acquired through the evolution and can be classified into three main classes, RING (really interesting new gene), HECT (homologous to the E6-AP carboxyl terminus) and NEL (novel E3 ligases). In this review we describe the roles played by different classes of bacterial Ub ligases in infection and pathogenicity. We also provide an overview of the different mechanisms by which bacteria mimic specific components of the host Ub system and outline the gaps in our current understanding of their functions. Additionally, we discuss approaches and experimental tools for validating this class of enzymes as potential novel antibacterial therapy targets. PMID:26964724

  8. Dectin-1-Dependent Interleukin-22 Contributes to Early Innate Lung Defense against Aspergillus fumigatus

    OpenAIRE

    Gessner, Melissa A.; Werner, Jessica L.; Lilly, Lauren M.; Nelson, Michael P.; Metz, Allison E.; Dunaway, Chad W; Chan, Yvonne R.; Ouyang, Wenjun; Brown, Gordon D.; Weaver, Casey T.; Steele, Chad

    2012-01-01

    We have previously reported that mice deficient in the beta-glucan receptor Dectin-1 displayed increased susceptibility to Aspergillus fumigatus lung infection in the presence of lower interleukin 23 (IL-23) and IL-17A production in the lungs and have reported a role for IL-17A in lung defense. As IL-23 is also thought to control the production of IL-22, we examined the role of Dectin-1 in IL-22 production, as well as the role of IL-22 in innate host defense against A. fumigatus. Here, we sho...

  9. A viral suppressor protein inhibits host RNA silencing by hooking up with Argonautes

    KAUST Repository

    Jin, Hailing

    2010-05-01

    RNA viruses are particularly vulnerable to RNAi-based defenses in the host, and thus have evolved specific proteins, known as viral suppressors of RNA silencing (VSRs), as a counterdefense. In this issue of Genes & Development, Azevedo and colleagues (pp. 904-915) discovered that P38, the VSR of Turnip crinkle virus, uses its glycine/tryptophane (GW) motifs as an ARGONAUTE (AGO) hook to attract and disarm the host\\'s essential effector of RNA silencing. Several GW motif-containing cellular proteins are known to be important partners of AGOs in RNA silencing effector complexes in yeast, plants, and animals. The GW motif appears to be a versatile and effective tool for regulating the activities of RNA silencing pathways, and the use of GW mimicry to compete for and inhibit host AGOs may be a strategy used by many pathogens to counteract host RNAi-based defenses. © 2010 by Cold Spring Harbor Laboratory Press.

  10. Agrobacterium infection and plant defense-transformation success hangs by a thread.

    Science.gov (United States)

    Pitzschke, Andrea

    2013-01-01

    The value of Agrobacterium tumefaciens for plant molecular biologists cannot be appreciated enough. This soil-borne pathogen has the unique capability to transfer DNA (T-DNA) into plant systems. Gene transfer involves both bacterial and host factors, and it is the orchestration of these factors that determines the success of transformation. Some plant species readily accept integration of foreign DNA, while others are recalcitrant. The timing and intensity of the microbially activated host defense repertoire sets the switch to "yes" or "no." This repertoire is comprised of the specific induction of mitogen-activated protein kinases (MAPKs), defense gene expression, production of reactive oxygen species (ROS) and hormonal adjustments. Agrobacterium tumefaciens abuses components of the host immunity system it mimics plant protein functions and manipulates hormone levels to bypass or override plant defenses. A better understanding of the ongoing molecular battle between agrobacteria and attacked hosts paves the way toward developing transformation protocols for recalcitrant plant species. This review highlights recent findings in agrobacterial transformation research conducted in diverse plant species. Efficiency-limiting factors, both of plant and bacterial origin, are summarized and discussed in a thought-provoking manner. PMID:24391655

  11. Host exploitation strategies of the social parasite Maculinea alcon

    DEFF Research Database (Denmark)

    Fürst, Matthias Alois

    . Throughout the first instars M. alcon lives on a specific food plant, however, in the last instar before pupation it develops into an obligate social parasite, posing a considerably cost to its host ant colony. I here focus on the different exploitation strategies of M. alcon throughout its lifecycle and the...... the nest where it will feed on ant regurgitations and ant brood. It is thus crucial for the caterpillar's survival to attract the host ant, get picked up and brought back to the ant's colony. My study shows that 3rd and 4th instar caterpillars are distinct from each other not only morphologically but...... caterpillar constitutes a fitness cost to infected host ant colonies, the host ants are expected to have developed defense mechanisms in response to the presence of the social parasite. I was able to demonstrate that the efficiency of ant colonies to defend themselves against intruders depends on a multitude...

  12. Antibacterial, Antifungal and Cytotoxic Activities of Tuberous Roots of Amorphophallus campanulatus

    OpenAIRE

    Khan, Alam; Rahman, Moizur; Islam, Shariful

    2007-01-01

    Antibacterial, antifungal and cytotoxic activities of ethanol extract of tuberous roots of Amorphophallus campanulatus were studied. Disc diffusion technique was used to determine in vitro antibacterial and antifungal activities. Cytotoxicity was determined against brine shrimp nauplii. In addition, minimum inhibitory concentration (MIC) was determined using serial dilution technique to determine antibacterial potency. The extract showed significant antibacterial activities against four gram-...

  13. The antibacterial effect of nitric oxide against ESBL-producing uropathogenic E. coli is improved by combination with miconazole and polymyxin B nonapeptide

    OpenAIRE

    Bang, Charlotte Sahlberg; Kinnunen, Annica; Karlsson, Marie; Önnberg, Anna; Söderquist, Bo; Persson, Katarina

    2014-01-01

    Background Nitric oxide (NO) is produced as part of the host immune response to bacterial infections, including urinary tract infections. The enzyme flavohemoglobin, coded by the hmp gene, is involved in protecting bacterial cells from the toxic effects of NO and represents a potentially interesting target for development of novel treatment concepts against resistant uropathogenic bacteria. The aim of the present study was to investigate if the in vitro antibacterial effects of NO can be enha...

  14. Silver Nanoparticles as Potential Antibacterial Agents

    Directory of Open Access Journals (Sweden)

    Gianluigi Franci

    2015-05-01

    Full Text Available Multi-drug resistance is a growing problem in the treatment of infectious diseases and the widespread use of broad-spectrum antibiotics has produced antibiotic resistance for many human bacterial pathogens. Advances in nanotechnology have opened new horizons in nanomedicine, allowing the synthesis of nanoparticles that can be assembled into complex architectures. Novel studies and technologies are devoted to understanding the mechanisms of disease for the design of new drugs, but unfortunately infectious diseases continue to be a major health burden worldwide. Since ancient times, silver was known for its anti-bacterial effects and for centuries it has been used for prevention and control of disparate infections. Currently nanotechnology and nanomaterials are fully integrated in common applications and objects that we use every day. In addition, the silver nanoparticles are attracting much interest because of their potent antibacterial activity. Many studies have also shown an important activity of silver nanoparticles against bacterial biofilms. This review aims to summarize the emerging efforts to address current challenges and solutions in the treatment of infectious diseases, particularly the use of nanosilver antimicrobials.

  15. Quaternary Ammonium Polyethyleneimine: Antibacterial Activity Ira

    International Nuclear Information System (INIS)

    Quaternary ammonium polyethyleneimine- (QA-PEI-) based nanoparticles were synthesized using two synthetic methods, reductive amination and N-alkylation. According to the first method, QA-PEI nanoparticles were synthesized by cross-linking with glutaraldehyde followed by reductive amination with octanal and further N-methylation with methyl iodide. The second method is based on crosslinking with dialkyl halide followed by N-alkylation with octyl halide and further N-methylation with methyl iodide. QA-PEI nanoparticles completely inhibited bacterial growth (>106 bacteria), including both Gram-positive, that is, Staphylococcus aureus at 80 μ/mL, and Gram-negative, that is, Escherichia coli at 320 μ/mL. Activity analysis revealed that the degree of alkylation and N-methylation of the QA-PEI nanoparticles plays a significant role in antibacterial activity of the reagent. The most potent compound was octyl alkylated QA-PEI alkylated at 1 : 1 mole ratio (primary amine of PEI monomer units/alkylating agent). Also, cytotoxicity studies on MAT-LyLu and MBT cell lines were performed with QA-PEI nanoparticles. These findings confirm previous reports that poly cations bearing quaternary ammonium moieties inhibit bacterial growth in vitro and have a potential use as additives in medical devices which need antibacterial properties.

  16. Silver nanoparticles as potential antibacterial agents.

    Science.gov (United States)

    Franci, Gianluigi; Falanga, Annarita; Galdiero, Stefania; Palomba, Luciana; Rai, Mahendra; Morelli, Giancarlo; Galdiero, Massimiliano

    2015-01-01

    Multi-drug resistance is a growing problem in the treatment of infectious diseases and the widespread use of broad-spectrum antibiotics has produced antibiotic resistance for many human bacterial pathogens. Advances in nanotechnology have opened new horizons in nanomedicine, allowing the synthesis of nanoparticles that can be assembled into complex architectures. Novel studies and technologies are devoted to understanding the mechanisms of disease for the design of new drugs, but unfortunately infectious diseases continue to be a major health burden worldwide. Since ancient times, silver was known for its anti-bacterial effects and for centuries it has been used for prevention and control of disparate infections. Currently nanotechnology and nanomaterials are fully integrated in common applications and objects that we use every day. In addition, the silver nanoparticles are attracting much interest because of their potent antibacterial activity. Many studies have also shown an important activity of silver nanoparticles against bacterial biofilms. This review aims to summarize the emerging efforts to address current challenges and solutions in the treatment of infectious diseases, particularly the use of nanosilver antimicrobials. PMID:25993417

  17. Antibacterial ceramic for sandbox. Sunabayo kokin ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, K. (Ishizuka Glass Co. Ltd. Nagoya (Japan))

    1993-10-01

    Sands in sandboxes in parks have been called into question of being contaminated by colon bacilli and spawns from ascarides. This paper introduces an antibacterial ceramic for sandbox developed as a new material effective to help reduce the contamination. The ceramic uses natural sand as the main raw material, which is added with borax and silver to contain silver ions that have bacteria and fungus resistance and deodorizing effect. The ceramic has an average grain size ranging from 0.5 mm to 0.7 mm, and is so devised as to match specific gravity, grain size and shape of the sand, hence no separation and segregation can occur. The result of weatherability and antibacterial strength tests on sand for a sandbox mixed with the ceramic at 1% suggests that its efficacy lasts for about three years. Its actual use is under observation. Its efficacy has been verified in a test that measures a survival factor of spawns from dog ascardides contacted with aqueous solution containing the ceramic at 1%. Safety and sanitation tests have proved the ceramic a highly safe product that conforms to the food sanitation law. 5 refs., 3 figs., 3 tabs.

  18. Photodynamic antibacterial effect of graphene quantum dots.

    Science.gov (United States)

    Ristic, Biljana Z; Milenkovic, Marina M; Dakic, Ivana R; Todorovic-Markovic, Biljana M; Milosavljevic, Momir S; Budimir, Milica D; Paunovic, Verica G; Dramicanin, Miroslav D; Markovic, Zoran M; Trajkovic, Vladimir S

    2014-05-01

    Synthesis of new antibacterial agents is becoming increasingly important in light of the emerging antibiotic resistance. In the present study we report that electrochemically produced graphene quantum dots (GQD), a new class of carbon nanoparticles, generate reactive oxygen species when photoexcited (470 nm, 1 W), and kill two strains of pathogenic bacteria, methicillin-resistant Staphylococcus aureus and Escherichia coli. Bacterial killing was demonstrated by the reduction in number of bacterial colonies in a standard plate count method, the increase in propidium iodide uptake confirming the cell membrane damage, as well as by morphological defects visualized by atomic force microscopy. The induction of oxidative stress in bacteria exposed to photoexcited GQD was confirmed by staining with a redox-sensitive fluorochrome dihydrorhodamine 123. Neither GQD nor light exposure alone were able to cause oxidative stress and reduce the viability of bacteria. Importantly, mouse spleen cells were markedly less sensitive in the same experimental conditions, thus indicating a fairly selective antibacterial photodynamic action of GQD. PMID:24612819

  19. Investment in defense and cost of predator-induced defense along a resource gradient

    DEFF Research Database (Denmark)

    Steiner, Uli

    2007-01-01

    this study, I exposed tadpoles to caged predators along a resource gradient in order to estimate investment in defense and costs of defense by assessing predator-induced plasticity. Induced defenses included increased tail depth, reduced feeding, and reduced swimming activity; costs associated with...

  20. Five Ochna species have high antibacterial activity and more than ten antibacterial compounds

    Directory of Open Access Journals (Sweden)

    Jacobus N. Eloff

    2012-01-01

    Full Text Available New measures to control infections in humans and other animals are continuously being sought because of the increasing resistance of bacteria to antibiotics. In a wide tree screening survey of the antimicrobial activity of extracts of tree leaves (www.up.ac.za/phyto, Ochna pulchra, a small tree found widely in southern Africa, had good antibacterial activity. We therefore investigated the antibacterial activity of acetone leaf extracts of some other available Ochna spp. Antibacterial activity and the number of antibacterial compounds in acetone leaf extracts of Ochna natalitia, Ochna pretoriensis, O. pulchra, Ochna gamostigmata and Ochna serullata were determined with a tetrazolium violet serial microplate dilution assay and bioautography against Staphylococcus aureus, Escherichia coli, Enterococcus faecalis and Pseudomonas aeruginosa, bacteria commonly associated with nosocomial infections. The percentage yields of the extracts varied from 2.5% to 8%. The minimum inhibitory concentrations of the five species ranged from 40 µg/mL to 1250 µg/mL. E. coli was sensitive to all the extracts. The O. pretoriensis extract was the most active with minimum inhibitory concentrations of 0.065 mg/mL and 0.039 mg/mL against E. coli and E. faecalis, respectively. The O. pretoriensis extract also had the highest total activities of 923 mL/g and 1538 mL/g, indicating that the acetone extract from 1 g of dried plant material could be diluted to 923 mL or 1538 mL and would still kill these bacteria. Based on the bioautography results, the two most active species, O. pretoriensis and O. pulchra, contained at least 10 antibacterial compounds with similar Rf values. Some of these antibacterial compounds were polar and others were non-polar. Variation in the chemical composition of the species

  1. Competition for Manganese at the Host-Pathogen Interface.

    Science.gov (United States)

    Kelliher, J L; Kehl-Fie, T E

    2016-01-01

    Transition metals such as manganese are essential nutrients for both pathogen and host. Vertebrates exploit this necessity to combat invading microbes by restricting access to these critical nutrients, a defense known as nutritional immunity. During infection, the host uses several mechanisms to impose manganese limitation. These include removal of manganese from the phagolysosome, sequestration of extracellular manganese, and utilization of other metals to prevent bacterial acquisition of manganese. In order to cause disease, pathogens employ a variety of mechanisms that enable them to adapt to and counter nutritional immunity. These adaptations include, but are likely not limited to, manganese-sensing regulators and high-affinity manganese transporters. Even though successful pathogens can overcome host-imposed manganese starvation, this defense inhibits manganese-dependent processes, reducing the ability of these microbes to cause disease. While the full impact of host-imposed manganese starvation on bacteria is unknown, critical bacterial virulence factors such as superoxide dismutases are inhibited. This chapter will review the factors involved in the competition for manganese at the host-pathogen interface and discuss the impact that limiting the availability of this metal has on invading bacteria. PMID:27571690

  2. The Defense Mechanisms of Coronary Patients.

    Science.gov (United States)

    Peglar, Marian; Borgen, Fred H.

    1984-01-01

    Tested 73 male inpatients with coronary heart disease on the Defense Mechanisms Inventory, State-Trait Anxiety Inventory, and a perception of health measure. Subjects were followed for five years. Principalization was discovered to be the most successful and projection the least successful defense. (JAC)

  3. Protecting the Self: Defense Mechanisms in Action

    Science.gov (United States)

    Cramer, Phebe

    2006-01-01

    Integrating theory, research, and practical applications, this book provides a comprehensive examination of defense mechanisms and their role in both normal development and psychopathology. The author describes how children and adults mobilize specific kinds of defenses to maintain their psychological equilibrium and preserve self-esteem,…

  4. Policy implications of the Strategic Defense Initiative

    International Nuclear Information System (INIS)

    Specific topics include: the technological feasibility of proposed components and architectures; the compatibility of the proposed systems with existing and proposed arms control agreements, with special emphasis upon the ABM Treaty, Outer Space Treaty, the Defense and Space Treaty, and the START Treaty; the compatibility of proposed systems with classical warfare doctrine and the four modern strategic nuclear doctrines of Massive Retaliation, Assured Destruction, Countervailing and Flexible Response; the economics of strategic defense including an assessment of overall governmental spending, of the suballocation for defense, and of the feasibility of defensive systems which are cost-effective at the margin; and, in summary, an assessment of the New Strategic Concept which balances arms control, offensive forces, and defensive forces. This study falls within the realm of defense policy analysis in that it attempts to determine whether the administration's proposed Strategic Defense Initiative, as well as the long-term strategic defensive systems derived from SDI research, constitute efficient, desirable allocation of scarce government resources - especially in a period of seemingly relaxed superpower tensions and numerous demands upon those resources

  5. Survival of Bemisia tabaci and activity of plant defense-related enzymes in genotypes of Capsicum annuum L.

    OpenAIRE

    Luis Latournerie-Moreno; Alex Ic-Caamal; Esaú Ruiz-Sánchez; Horacio Ballina-Gómez; Ignacio Islas-Flores; Wilberth Chan-Cupul; Daniel González-Mendoza

    2015-01-01

    The whitefly Bemisia tabaci (Gennadius, 1889) is a major plant pest of horticultural crops from the families Solanaceae, Fabaceae and Cucurbitaceae in Neotropical areas. The exploration of host plant resistance and their biochemical mechanisms offers an excellent alternative to better understand factors affecting the interaction between phytophagous insect and host plant. We evaluated the survival of B. tabaci in landrace genotypes of Capsicum annuum L., and the activity of plant defense-rela...

  6. Cirrhosis-induced defects in innate pulmonary defenses against Streptococcus pneumoniae

    Directory of Open Access Journals (Sweden)

    Vander Top Elizabeth A

    2007-10-01

    Full Text Available Abstract Background The risk of mortality from pneumonia caused by Streptococcus pneumoniae is increased in patients with cirrhosis. However, the specific pneumococcal virulence factors and host immune defects responsible for this finding have not been clearly established. This study used a cirrhotic rat model of pneumococcal pneumonia to identify defect(s in innate pulmonary defenses in the cirrhotic host and to determine the impact of the pneumococcal toxin pneumolysin on these defenses in the setting of severe cirrhosis. Results No cirrhosis-associated defects in mucociliary clearance of pneumococci were found in these studies, but early intrapulmonary killing of the organisms before the arrival of neutrophils was significantly impaired. This defect was exacerbated by pneumolysin production in cirrhotic but not in control rats. Neutrophil-mediated killing of a particularly virulent type 3 pneumococcal strain also was significantly diminished within the lungs of cirrhotic rats with ascites. Levels of lysozyme and complement component C3 were both significantly reduced in bronchoalveolar lavage fluid from cirrhotic rats. Finally, complement deposition was reduced on the surface of pneumococci recovered from the lungs of cirrhotic rats in comparison to organisms recovered from the lungs of control animals. Conclusion Increased mortality from pneumococcal pneumonia in this cirrhotic host is related to defects in both early pre-neutrophil- and later neutrophil-mediated pulmonary killing of the organisms. The fact that pneumolysin production impaired pre-neutrophil-mediated pneumococcal killing in cirrhotic but not control rats suggests that pneumolysin may be particularly detrimental to this defense mechanism in the severely cirrhotic host. The decrease in neutrophil-mediated killing of pneumococci within the lungs of the cirrhotic host is related to insufficient deposition of host proteins such as complement C3 on their surfaces. Pneumolysin

  7. ANTIBACTERIAL ACTIVITY OF GINGER OIL AGAINST FOOD BORN PATHOGENS

    International Nuclear Information System (INIS)

    This study was carried out to investigate the antibacterial activity of ginger oil against Food Born pathogens and the effect of heating, microwave heating and gamma irradiation on microbiological quality and antibacterial activity of ginger oil. Growth and survival of A. hydrophila and L. monocytogenes in broth media and carrot juice with different concentrations of ginger oil was also studied. Gram-negative bacteria were more resistant than gram-positive bacteria. Heating at 800C for 10 min did not change the antibacterial activity of ginger oil, whereas heating at 1000C for 5 min and autoclaving at 1210C for 15 min caused slight reduction in antibacterial activity in most microorganisms tested. Heating by microwave of ginger oil destroyed its antibacterial activity against B. cereus although it still works against other microorganisms tested. The dose 6 kGy caused slight reduction in antibacterial activity of ginger oil, whereas the dose 10 kGy caused markedly reduction in antibacterial activity of ginger oil against most microorganisms tested. Ginger oil was more effective on L. monocytogenes as compared with its effect on A. hydrophila in tryptone soya broth at 40C or 250C. Supplementation of ginger oil with carrot juice was more effective on A. hydrophila and L. monocytogenes than in tryptone soya broth and this effect was increased with increasing the time of incubation and the concentration of ginger oil. These results support the notion that plant essential oils may have an important role as pharmaceuticals and food preservatives

  8. Antibacterial effects of Solanum tuberosum peel ethanol extract in vitro

    Directory of Open Access Journals (Sweden)

    Amanpour Raana

    2015-04-01

    Full Text Available Introduction: Today, medicinal plants are being widely used due to being natural, available, and cheaper than synthetic drugs and having minimum side effects. Since there were reports about the antibacterial properties of Solanum tuberosum (SE, the aim of this study was to investigate the antibacterial effects of SE ethanol extract in vitro condition on Streptococcus pyogenes, Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella pneumoniae. Methods: Ethanol extract of SE peel was prepared by maceration method. Initially, antibacterial activity of ethanol extract of SE was qualitatively determined by disk diffusion test; then, the minimum inhibitory concentration and minimum bactericidal concentration were qualitatively determined by micro-dilution method. Results: SE peel extract had antibacterial properties and its effect was more pronounced on gram-positive bacteria, especially S. aureus (0.62±0.00 mg/ml. The extract had antibacterial activity on gram-negative bacteria, P. aeruginosa, too (8.33±2.88 mg/ml. Conclusion: SE peel extract has antibacterial activity and its effect on gram-positive bacteria was more pronounced than the investigated gram-negative bacteria. Therefore, it is suggested that SE peel constituent compounds be determined and to determine the exact mechanism of its antibacterial properties, and more comprehensive research be done to apply it, clinically.

  9. Antibacterial Activity of Dental Cements Containing Quaternary Ammonium Polyethylenimine Nanoparticles

    International Nuclear Information System (INIS)

    Glass ionomer cements (GICs) are commonly used for cementing full cast crown restorations. Regrettably, although the dental cements fill the gap between the tooth and the crown, bacterial micro leakage may occur, resulting in secondary caries. As micro leakage cannot be completely prevented, GCS possessing antibacterial properties are in demand. In the present study the antibacterial activity of insoluble, cross-linked quaternary ammonium polyethylenimine (Qp) nanoparticles incorporated at 1% w/w in two clinically available GCS were studied. The antibacterial activity was tested against Streptococcus mutans and Lactobacillus casei using the direct contact test (Dct) and the agar diffusion test (Ad). Using the direct contact test, antibacterial activity (P<0.05) was found in both tested GICs with incorporated QPEI nanoparticles, the effect lasting for at least one month. However, the ADT showed no inhibition halo in the test bacteria, indicating that the antimicrobial nanoparticles do not diffuse into the agar. The results show that the incorporation of QPEI nanoparticles in glass ionomer cements has a long-lasting antibacterial effect against Streptococcus mutans and Lactobacillus casei. Changing the antibacterial properties of glass ionomer cements by incorporating QPEI antibacterial nanoparticles may prolong the clinical performance of dental crowns.

  10. Antibacterial Effect of Diclofenac Sodium on Enterococcus faecalis

    Directory of Open Access Journals (Sweden)

    Amin Salemmilani

    2013-01-01

    Full Text Available Objective: Non-steroidal anti-inflammatory drugs (NSAIDs have shown antibacterial activity in some recent studies. The aim of this study was to evaluate the antibacterial effect of diclofenac against Enterococcus faecalis (E. faecalis as a resistant endodontic bacterium in comparison with ibuprofen, calcium hydroxide and amoxicillin.Materials and Methods: The antibacterial activity of materials was evaluated using agar diffusion test and tube dilution method. Mixtures of 400 mg/ml of materials were prepared. The bacteria were seeded on 10 Muller-Hinton agar culture plates. Thirty microliter of each test material was placed in each well punched in agar plates. After incubation, the zone of bacterial inhibition was measured. Minimum inhibitory concentration (MIC of the test materials was determined by agar dilution method. One-way Analysis of Variance (ANOVA followed by Sidak post hoc test was used to compare the mean zone of microbial growth in the groups.Results: There were significant differences between the two groups (p< 0.05. Results of the agar diffusion test showed that antibiotics (amoxicillin, gentamycin had the greatest antibacterial activity followed by NSAIDs (ibuprofen, diclofenac. Ca(OH2 failed to show antibacterial activity. Diclofenac and ibuprofen showed distinct antibacterial activity against E. faecalis in 50 µg/ml and above concentrations.Conclusion: Within the limitations of this in vitro study, it is concluded that diclofenac and ibuprofen have significantly more pronounced antibacterial activity against E. faecalis in comparison with Ca(OH2.

  11. Antibacterial kaolinite/urea/chlorhexidine nanocomposites: Experiment and molecular modelling

    International Nuclear Information System (INIS)

    Clay minerals are commonly used materials in pharmaceutical production both as inorganic carriers or active agents. The purpose of this study is the preparation and characterization of clay/antibacterial drug hybrids which can be further included in drug delivery systems for treatment oral infections. Novel nanocomposites with antibacterial properties were successfully prepared by ion exchange reaction from two types of kaolinite/urea intercalates and chlorhexidine diacetate. Intercalation compounds of kaolinite were prepared by reaction with solid urea in the absence of solvents (dry method) as well as with urea aqueous solution (wet method). The antibacterial activity of two prepared samples against Enterococcus faecalis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa was evaluated by finding the minimum inhibitory concentration (MIC). Antibacterial studies of both samples showed the lowest MIC values (0.01%, w/v) after 1 day against E. faecalis, E. coli and S. aureus. A slightly worse antibacterial activity was observed against P. aeruginosa (MIC 0.12%, w/v) after 1 day. Since samples showed very good antibacterial activity, especially after 1 day of action, this means that these samples can be used as long-acting antibacterial materials. Prepared samples were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The experimental data are supported by results of molecular modelling.

  12. Antibacterial kaolinite/urea/chlorhexidine nanocomposites: Experiment and molecular modelling

    Energy Technology Data Exchange (ETDEWEB)

    Holešová, Sylva, E-mail: sylva.holesova@vsb.cz [Nanotechnology Centre, VŠB – Technical University of Ostrava, 17.listopadu 15/2172, CZ-708 33 Ostrava, Poruba (Czech Republic); IT4Innovations Centre of Excellence, VŠB – Technical University of Ostrava, 17.listopadu 15/2172, CZ-708 33 Ostrava, Poruba (Czech Republic); Valášková, Marta; Hlaváč, Dominik [Nanotechnology Centre, VŠB – Technical University of Ostrava, 17.listopadu 15/2172, CZ-708 33 Ostrava, Poruba (Czech Republic); IT4Innovations Centre of Excellence, VŠB – Technical University of Ostrava, 17.listopadu 15/2172, CZ-708 33 Ostrava, Poruba (Czech Republic); Madejová, Jana [Institute of Inorganic Chemistry, SAS, Dúbravská cesta 9, SK-845 36 Bratislava (Slovakia); Samlíková, Magda; Tokarský, Jonáš [Nanotechnology Centre, VŠB – Technical University of Ostrava, 17.listopadu 15/2172, CZ-708 33 Ostrava, Poruba (Czech Republic); IT4Innovations Centre of Excellence, VŠB – Technical University of Ostrava, 17.listopadu 15/2172, CZ-708 33 Ostrava, Poruba (Czech Republic); Pazdziora, Erich [Institute of Public Health Ostrava, Centre of Clinical Laboratories, Partyzánské náměstí 7, CZ-702 00 Ostrava (Czech Republic)

    2014-06-01

    Clay minerals are commonly used materials in pharmaceutical production both as inorganic carriers or active agents. The purpose of this study is the preparation and characterization of clay/antibacterial drug hybrids which can be further included in drug delivery systems for treatment oral infections. Novel nanocomposites with antibacterial properties were successfully prepared by ion exchange reaction from two types of kaolinite/urea intercalates and chlorhexidine diacetate. Intercalation compounds of kaolinite were prepared by reaction with solid urea in the absence of solvents (dry method) as well as with urea aqueous solution (wet method). The antibacterial activity of two prepared samples against Enterococcus faecalis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa was evaluated by finding the minimum inhibitory concentration (MIC). Antibacterial studies of both samples showed the lowest MIC values (0.01%, w/v) after 1 day against E. faecalis, E. coli and S. aureus. A slightly worse antibacterial activity was observed against P. aeruginosa (MIC 0.12%, w/v) after 1 day. Since samples showed very good antibacterial activity, especially after 1 day of action, this means that these samples can be used as long-acting antibacterial materials. Prepared samples were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The experimental data are supported by results of molecular modelling.

  13. Uncovering the transcriptional control of "Bartonella henselae" host adaptation factors

    OpenAIRE

    Québatte, Maxime

    2014-01-01

    A recurrent theme in bacterial pathogenicity is the understanding of the regulatory events necessary for a given pathogen to progress through its infection cycle while resisting the host defense mechanisms. This progression typically requires the coordinated expression of defined sub-portions of the virulence repertoire at the same time as others need to be tightly repressed or degraded. This so-called adaptive response is ultimately linked to the ability of the pathogen to sense its direct e...

  14. Primitive defenses: cognitive aspects and therapeutic handling.

    Science.gov (United States)

    Groh, L S

    In this paper the primitive defenses first described by Melanie Klein under the label of "schizoid mechanisms" are examined. The defenses considered are splitting the pathological uses of identification and projective identification, and the psychotic forms of denial. This examination is twofold: (1) the cognitive aspects of these defenses as described in terms of concepts developed by Jean Piaget; (2) concrete examples of the operation of these defenses during the treatment of schizophrenic patients are given and the effects of interventions based on the cognitive analysis are described. It is stressed that at times interventions, such as interpretation and confrontation, based on cognitive analysis, can temporarily and in some instances even permanently stop the operation of these defenses, allowing emotionally meaningful material to emerge which expedites the therapeutic process. PMID:7429737

  15. Exopolysacharides from White Rot Fungi and Their Antibacterial Studies

    Directory of Open Access Journals (Sweden)

    V. Pranitha

    2016-06-01

    Full Text Available In current investigation exopolysacharides are produced from the Trametes sp. and antibacterial activity of exopolysaccharides (EPS was studied. The antibacterial effect of EPS was observed that they were most effective against gram-positive bacteria, especially B. subtilis and S.aureaus with a zone of inhibition 24 mm and 28 mm, respectively, at a concentration of 80 mg/ml. Moreover, with the increasing concentration, the EPS showed significant increase in antibacterial activity. The activity was lowest in the inhibition of gram-negative bacterium, E. coli and P aerogenosa at a low concentration whose inhibition zones are between 5 to 15mm.

  16. Synthesis and antibacterial properties of copper nanoparticles for Salmonella typhi

    Science.gov (United States)

    Jaiswal, Anamika; Gaherwal, S.; Lodhi, Pavitra Devi; Singh, Jaiveer; Kaurav, Netram; Shrivastava, M. M. P.

    2016-05-01

    In this study, the antibacterial properties of Cu nanoparitcles (Cu-NPs) were investigated against Salmonella typhi. The Cu-NPs were prepared by the reduction of cupper acetate with the help of ethylene glycol (EG), then sample was characterized by XRD for its average particle size identification. The antibacterial activity assessed by well diffusion and disc diffusion method on different concentration of nanoparticles. It was found that these Cu-NPs showed antibacterial activity in form of zone inhibition, wherein, zone of inhibition increased with increase in concentration of Cu-NPs.

  17. Silverleaf whitefly induces salicylic acid defenses and suppresses effectual jasmonic acid defenses.

    Science.gov (United States)

    Zarate, Sonia I; Kempema, Louisa A; Walling, Linda L

    2007-02-01

    The basal defenses important in curtailing the development of the phloem-feeding silverleaf whitefly (Bemisia tabaci type B; SLWF) on Arabidopsis (Arabidopsis thaliana) were investigated. Sentinel defense gene RNAs were monitored in SLWF-infested and control plants. Salicylic acid (SA)-responsive gene transcripts accumulated locally (PR1, BGL2, PR5, SID2, EDS5, PAD4) and systemically (PR1, BGL2, PR5) during SLWF nymph feeding. In contrast, jasmonic acid (JA)- and ethylene-dependent RNAs (PDF1.2, VSP1, HEL, THI2.1, FAD3, ERS1, ERF1) were repressed or not modulated in SLWF-infested leaves. To test for a role of SA and JA pathways in basal defense, SLWF development on mutant and transgenic lines that constitutively activate or impair defense pathways was determined. By monitoring the percentage of SLWF nymphs in each instar, we show that mutants that activate SA defenses (cim10) or impair JA defenses (coi1) accelerated SLWF nymphal development. Reciprocally, mutants that activate JA defenses (cev1) or impair SA defenses (npr1, NahG) slowed SLWF nymphal development. Furthermore, when npr1 plants, which do not activate downstream SA defenses, were treated with methyl jasmonate, a dramatic delay in nymph development was observed. Collectively, these results showed that SLWF-repressed, JA-regulated defenses were associated with basal defense to the SLWF. PMID:17189328

  18. Silverleaf Whitefly Induces Salicylic Acid Defenses and Suppresses Effectual Jasmonic Acid Defenses1[W][OA

    Science.gov (United States)

    Zarate, Sonia I.; Kempema, Louisa A.; Walling, Linda L.

    2007-01-01

    The basal defenses important in curtailing the development of the phloem-feeding silverleaf whitefly (Bemisia tabaci type B; SLWF) on Arabidopsis (Arabidopsis thaliana) were investigated. Sentinel defense gene RNAs were monitored in SLWF-infested and control plants. Salicylic acid (SA)-responsive gene transcripts accumulated locally (PR1, BGL2, PR5, SID2, EDS5, PAD4) and systemically (PR1, BGL2, PR5) during SLWF nymph feeding. In contrast, jasmonic acid (JA)- and ethylene-dependent RNAs (PDF1.2, VSP1, HEL, THI2.1, FAD3, ERS1, ERF1) were repressed or not modulated in SLWF-infested leaves. To test for a role of SA and JA pathways in basal defense, SLWF development on mutant and transgenic lines that constitutively activate or impair defense pathways was determined. By monitoring the percentage of SLWF nymphs in each instar, we show that mutants that activate SA defenses (cim10) or impair JA defenses (coi1) accelerated SLWF nymphal development. Reciprocally, mutants that activate JA defenses (cev1) or impair SA defenses (npr1, NahG) slowed SLWF nymphal development. Furthermore, when npr1 plants, which do not activate downstream SA defenses, were treated with methyl jasmonate, a dramatic delay in nymph development was observed. Collectively, these results showed that SLWF-repressed, JA-regulated defenses were associated with basal defense to the SLWF. PMID:17189328

  19. Addition of antibacterial agents to MMA-TBB dentin bonding systems--influence on tensile bond strength and antibacterial effect.

    Science.gov (United States)

    Kudou, Y; Obara, K; Kawashima, T; Kubota, M; Abe, S; Endo, T; Komatsu, M; Okuda, R

    2000-03-01

    To produce a bonding system which has both high bond strength and antibacterial properties, an antibacterial agent (vancomycin: VCM or metronidazol: MN) was added to the PMMA powder of 4-META/MMA-TBB resin (CB). The influence of the addition of an antibacterial agent on tensile bond strength to dentin and the antibacterial effect were investigated in this study. Forty-seven freshly extracted bovine first or second incisors were used to measure the tensile bond strength to dentin. The bond strengths to bovine dentin were not significantly decreased by addition of VCM (1%, 2%, 5%), or MN (1%) to CB (p diffusion method, analyzing the appearance of the inhibition zone around a resin disk following anaerobic culturing. The resin disks containing VCM showed antibacterial effects on all of the strains examined; the widths of the inhibition zones were 4-15 mm. The resin disks containing MN showed antibacterial effects on three strains; the widths of the inhibition zones were 0-4 mm. It was thus possible to produce a bonding system with both antibacterial effect and high tensile bond strength by addition of VCM to PMMA powder. PMID:11219091

  20. Design, Synthesis, Molecular Docking, and Antibacterial Evaluation of Some Novel Flouroquinolone Derivatives as Potent Antibacterial Agent

    Directory of Open Access Journals (Sweden)

    Mehul M. Patel

    2014-01-01

    Full Text Available Objective. Quinolone moiety is an important class of nitrogen containing heterocycles widely used as key building blocks for medicinal agents. It exhibits a wide spectrum of pharmacophores and has bactericidal, antiviral, antimalarial, and anticancer activities. In view of the reported antimicrobial activity of various fluoroquinolones, the importance of the C-7 substituents is that they exhibit potent antimicrobial activities. Our objective was to synthesize newer quinolone analogues with increasing bulk at C-7 position of the main 6-fluoroquinolone scaffold to produce the target compounds which have potent antimicrobial activity. Methods. A novel series of 1-ethyl-6-fluoro-4-oxo-7-{4-[2-(4-substituted phenyl-2-(substituted-ethyl]-1-piperazinyl}-1,4-dihydroquinoline-3-carboxylic acid derivatives were synthesized. To understand the interaction of binding sites with bacterial protein receptor, the docking study was performed using topoisomerase II DNA gyrase enzymes (PDB ID: 2XCT by Schrodinger’s Maestro program. In vitro antibacterial activity of the synthesized compounds was studied and the MIC value was calculated by the broth dilution method. Results. Among all the synthesized compounds, some compounds showed potent antimicrobial activity. The compound 8g exhibited good antibacterial activity. Conclusion. This investigation identified the potent antibacterial agents against certain infections.