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Sample records for lipopeptides induce systemic

  1. Synthetic ultrashort cationic lipopeptides induce systemic plant defense responses against bacterial and fungal pathogens.

    PubMed

    Brotman, Yariv; Makovitzki, Arik; Shai, Yechiel; Chet, Ilan; Viterbo, Ada

    2009-08-01

    A new family of synthetic, membrane-active, ultrashort lipopeptides composed of only four amino acids linked to fatty acids was tested for the ability to induce systemic resistance and defense responses in plants. We found that two peptides wherein the third residue is a d-enantiomer (italic), C16-KKKK and C16-KLLK, can induce medium alkalinization of tobacco suspension-cultured cells and expression of defense-related genes in cucumber and Arabidopsis seedlings. Moreover, these compounds can prime systemic induction of antimicrobial compounds in cucumber leaves similarly to the plant-beneficial fungus Trichoderma asperellum T203 and provide systemic protection against the phytopathogens Botrytis cinerea B05, Pseudomonas syringae pv. lachrimans, and P. syringae pv. tomato DC3000. Thus, short cationic lipopeptides are a new category of compounds with potentially high utility in the induction of systemic resistance in plants.

  2. Systemic resistance induced by Bacillus lipopeptides in Beta vulgaris reduces infection by the rhizomania disease vector Polymyxa betae.

    PubMed

    Desoignies, Nicolas; Schramme, Florence; Ongena, Marc; Legrève, Anne

    2013-05-01

    The control of rhizomania, one of the most important diseases of sugar beet caused by the Beet necrotic yellow vein virus, remains limited to varietal resistance. In this study, we investigated the putative action of Bacillus amylolequifaciens lipopeptides in achieving rhizomania biocontrol through the control of the virus vector Polymyxa betae. Some lipopeptides that are produced by bacteria, especially by plant growth-promoting rhizobacteria, have been found to induce systemic resistance in plants. We tested the impact of the elicitation of systemic resistance in sugar beet through lipopeptides on infection by P. betae. Lipopeptides were shown to effectively induce systemic resistance in both the roots and leaves of sugar beet, resulting in a significant reduction in P. betae infection. This article provides the first evidence that induced systemic resistance can reduce infection of sugar beet by P. betae.

  3. Intranasal administration of a synthetic lipopeptide without adjuvant induces systemic immune responses

    PubMed Central

    Benmohamed, Lbachir; Krishnan, Radhika; Auge, Catherine; Primus, James F; Diamond, Don J

    2002-01-01

    Parenteral injection of a lipopeptide containing a human leucocyte antigen (HLA)-A*0201-restricted cytotoxic T-lymphocyte (CTL) epitope from the human cytomegalovirus (HCMV) immunodominant matrix protein pp65 efficiently induces systemic CTL responses in HLA-A*0201 transgenic mice. In this study, we demonstrate that intranasal (i.n.) administration of this lipopeptide, covalently linked to a universal T helper (Th) epitope (PADRE), also induces potent systemic CTL responses. Immune responses were substantially reduced when the unlipidated peptide analogue was used (P<0·01). The induced CTL were CD8+, major histocompatibility complex (MHC) class I-restricted and CMV specific. Moreover, i.n. administration of this lipidated peptide elicited both systemic and local mucosal CD4+ T-cell proliferative responses, as well as antigen-specific delayed type hypersensitivity (DTH) immune responses. In contrast, mice receiving the unlipidated peptide analogue developed substantially reduced Th or DTH responses (P<0·05). These results highlight the usefulness and potential of lipopeptides delivered via mucosal routes as painless, safe, and non-invasive vaccines. PMID:11972639

  4. Endophytic Bacillus spp. produce antifungal lipopeptides and induce host defence gene expression in maize.

    PubMed

    Gond, Surendra K; Bergen, Marshall S; Torres, Mónica S; White, James F

    2015-03-01

    Endophytes are mutualistic symbionts within healthy plant tissues. In this study we isolated Bacillus spp. from seeds of several varieties of maize. Bacillus amyloliquifaciens or Bacillus subtilis were found to be present in all maize varieties examined in this study. To determine whether bacteria may produce antifungal compounds, generally lipopeptides in Bacillus spp., bacterial cultures were screened for production of lipopeptides. Lipopeptides were extracted by acid precipitation from liquid cultures of Bacillus spp. Lipopeptide extracts from Bacillus spp. isolated from Indian popcorn and yellow dent corn showed inhibitory activity against Fusarium moniliforme at 500μg per disk. Using MALDI-TOF mass spectrometry we detected the presence of antifungal iturin A, fengycin and bacillomycin in these isolates. PCR amplification also showed the presence of genes for iturin A and fengycin. B. subtilis (SG_JW.03) isolated from Indian popcorn showed strong inhibition of Arabidopsis seed mycoflora and enhanced seedling growth. We tested for the induction of defence gene expression in the host plant after treatment of plants with B. subtilis (SG_JW.03) and its lipopeptide extract using RT-qPCR. Roots of Indian popcorn seedlings treated with a suspension of B. subtilis (SG_JW.03) showed the induction of pathogenesis-related genes, including PR-1 and PR-4, which relate to plant defence against fungal pathogens. The lipopeptide extract alone did not increase the expression of these pathogenesis-related genes. Based on our study of maize endophytes, we hypothesize that, bacterial endophytes that naturally occur in many maize varieties may function to protect hosts by secreting antifungal lipopeptides that inhibit pathogens as well as inducing the up-regulation of pathogenesis-related genes of host plants (systemic acquired resistance).

  5. Role of phenazines and cyclic lipopeptides produced by pseudomonas sp. CMR12a in induced systemic resistance on rice and bean.

    PubMed

    Ma, Zongwang; Hua, Gia Khuong Hoang; Ongena, Marc; Höfte, Monica

    2016-08-25

    Pseudomonas sp. CMR12a produces two different classes of cyclic lipopeptides (CLPs) (orfamides and sessilins), which all play a role in direct antagonism against soilborne pathogens. Here we show that Pseudomonas sp. CMR12a is also able to induce systemic resistance to Magnaporthe oryzae on rice and to the web blight pathogen Rhizoctonia solani AG2-2 on bean. Plant assays with biosynthesis mutants of Pseudomonas sp. CMR12a impaired in the production of phenazines and/or CLPs and purified metabolites revealed that distinct bacterial determinants are responsible for inducing systemic resistance in these two pathosystems. In rice, mutants impaired in phenazine production completely lost their ability to induce systemic resistance, while a soil drench with pure phenazine-1-carboxamide (PCN) at a concentration of 0.1 or 1 μM was active in inducing resistance against M. oryzae. In bean, mutants that only produced phenazines, sessilins or orfamides were still able to induce systemic resistance against Rhizoctonia web blight, but a balanced production of these metabolites was needed. This study not only shows that Pseudomonas sp. CMR12a can protect rice to blast disease and bean to web blight disease, but also displays that the determinants involved in induced systemic resistance are plant, pathogen and concentration dependent.

  6. Induced systemic resistance responses in perennial ryegrass against Magnaporthe oryzae elicited by semi-purified surfactin lipopeptides and live cells of Bacillus amyloliquefaciens.

    PubMed

    Rahman, Alamgir; Uddin, Wakar; Wenner, Nancy G

    2015-08-01

    The suppressive ability of several strains of cyclic lipopeptide-producing Bacillus rhizobacteria to grey leaf spot disease caused by Magnaporthe oryzae has been documented previously; however, the underlying mechanism(s) involved in the induced systemic resistance (ISR) activity in perennial ryegrass (Lolium perenne L.) remains unknown. Root-drench application of solid-phase extraction (SPE)-enriched surfactin and live cells of mutant Bacillus amyloliquefaciens strain FZB42-AK3 (produces surfactin, but not bacillomycin D and fengycin) significantly reduced disease incidence and severity on perennial ryegrass. The application of the treatments revealed a pronounced multilayered ISR defence response activation via timely and enhanced accumulation of hydrogen peroxide (H2O2), elevated cell wall/apoplastic peroxidase activity, and deposition of callose and phenolic/polyphenolic compounds underneath the fungal appressoria in naïve leaves, which was significantly more intense in treated plants than in mock-treated controls. Moreover, a hypersensitive response (HR)-type reaction and enhanced expression of LpPrx (Prx, peroxidase), LpOXO4 (OXO, oxalate oxidase), LpPAL (PAL, phenylalanine ammonia lyase), LpLOXa (LOX, lipoxygenase), LpTHb (putative defensin) and LpDEFa (DEFa, putative defensin) in perennial ryegrass were associated with SPE-enriched surfactin and live AK3 cell treatments, acting as a second layer of defence when pre-invasive defence responses failed. The results indicate that ISR activity following surfactin perception may sensitize H2O2 -mediated defence responses, thereby providing perennial ryegrass with enhanced protection against M. oryzae.

  7. Development of a dendritic cell-targeting lipopeptide as an immunoadjuvant that inhibits tumor growth without inducing local inflammation.

    PubMed

    Akazawa, Takashi; Ohashi, Toshimitsu; Nakajima, Hiroko; Nishizawa, Yasuko; Kodama, Ken; Sugiura, Kikuya; Inaba, Toshio; Inoue, Norimitsu

    2014-12-15

    Materials used for the past 30 years as immunoadjuvants induce suboptimal antitumor immune responses and often cause undesirable local inflammation. Some bacterial lipopeptides that act as Toll-like receptor (TLR) 2 ligands activate immune cells as immunoadjuvants and induce antitumor effects. Here, we developed a new dendritic cell (DC)-targeting lipopeptide, h11c (P2C-ATPEDNGRSFS), which uses the CD11c-binding sequence of intracellular adhesion molecule-1 to selectively and efficiently activate DCs but not other immune cells. Although the h11c lipopeptide activated DCs similarly to an artificial lipopeptide, P2C-SKKKK (P2CSK4), via TLR2 in vitro, h11c induced more effective tumor inhibition than P2CSK4 at low doses in vivo with tumor antigens. Even without tumor antigens, h11c lipopeptide significantly inhibited tumor growth and induced tumor-specific cytotoxic T cells. P2CSK4 was retained subcutaneously at the vaccination site and induced severe local inflammation in in vivo experiments. In contrast, h11c was not retained at the vaccination site and was transported into the tumor within 24 hr. The recruitment of DCs into the tumor was induced by h11c more effectively, while P2CSK4 induced the accumulation of neutrophils leading to severe inflammation at the vaccination site. Because CD11b+ cells, but not CD11c+ cells, produced neutrophil chemotactic factors such as macrophage inflammatory protein (MIP)-2 in response to stimulation with TLR2 ligands, the DC-targeting lipopeptide h11c induced less MIP-2 production by splenocytes than P2CSK4. In this study, we succeeded in developing a novel immunoadjuvant, h11c, which effectively induces antitumor activity without adverse effects such as local inflammation via the selective activation of DCs.

  8. Synthetic mycoplasma-derived lipopeptide MALP-2 induces maturation and function of dendritic cells.

    PubMed

    Weigt, Henning; Mühlradt, Peter F; Emmendörffer, Andreas; Krug, Norbert; Braun, Armin

    2003-01-01

    Dendritic cells (DC) modulate immune responses depending on the nature of the antigens. Receptors capable of discriminating these antigens on the basis of the pathogen-associated molecular patterns (PAMP) belong to the Toll-like receptor (TLR) family. The macrophage-activating lipopeptide 2 kDa (MALP-2), a synthetic lipopeptide derived from Mycoplasma fermentans, signals through TLR-2 and TLR-6. The aim of this study was to examine whether MALP-2 can modulate the functional properties of human monocyte-derived DC. The effects of this treatment were compared to those of the TLR-4 agonist lipopolysaccharide (LPS). To ensure clinical applicability, DC were generated under serum-free conditions. MALP-2 and LPS stimulation induced the expression of CD83 and increased the expressions of CD80, CD86, HLA-ABC and CD40. Furthermore, both substances decreased the endocytotic capacity of DC and induced the release of bioactive TNF-alpha and IL-10, whereas LPS additionally increased IL-12 release. Pretreatment with both substances boosted the allostimulatory capacity of DC. In a coculture with autologous lymphocytes, either MALP-2 or LPS pretreated DC induced a marked proliferation of lymphocytes, but only DC prestimulated with MALP-2 activated lymphocytes to produce the cytokines IL-4, IL-5 and IFN-gamma. No polarisation of lymphocytes into T-helper (Th)1 or Th2 was detected. These data indicate that MALP-2 is a potential candidate to modulate DC for clinical applications.

  9. Pam2 lipopeptides systemically increase myeloid-derived suppressor cells through TLR2 signaling

    SciTech Connect

    Maruyama, Akira; Shime, Hiroaki Takeda, Yohei; Azuma, Masahiro; Matsumoto, Misako; Seya, Tsukasa

    2015-02-13

    Myeloid-derived suppressor cells (MDSCs) are immature myeloid cells that exhibit potent immunosuppressive activity. They are increased in tumor-bearing hosts and contribute to tumor development. Toll-like receptors (TLRs) on MDSCs may modulate the tumor-supporting properties of MDSCs through pattern-recognition. Pam2 lipopeptides represented by Pam2CSK4 serve as a TLR2 agonist to exert anti-tumor function by dendritic cell (DC)-priming that leads to NK cell activation and cytotoxic T cell proliferation. On the other hand, TLR2 enhances tumor cell progression/invasion by activating tumor-infiltrating macrophages. How MDSCs respond to TLR2 agonists has not yet been determined. In this study, we found intravenous administration of Pam2CSK4 systemically up-regulated the frequency of MDSCs in EG7 tumor-bearing mice. The frequency of tumor-infiltrating MDSCs was accordingly increased in response to Pam2CSK4. MDSCs were not increased by Pam2CSK4 stimuli in TLR2 knockout (KO) mice. Adoptive transfer experiments using CFSE-labeled MDSCs revealed that the TLR2-positive MDSCs survived long in tumor-bearing mice in response to Pam2CSK4 treatment. Since the increased MDSC population sustained immune-suppressive properties, our study suggests that Pam2CSK4-triggered TLR2 activation enhances the MDSC potential and suppress antitumor immune response in tumor microenvironment. - Highlights: • Pam2CSK4 administration induces systemic accumulation of CD11b{sup +}Gr1{sup +} MDSCs. • TLR2 is essential for Pam2CSK4-induced accumulation of CD11b{sup +}Gr1{sup +} MDSCs. • Pam2CSK4 supports survival of CD11b{sup +}Gr1{sup +} MDSCs in vivo.

  10. Ralstonia solanacearum lipopeptide induces chlamydospore development in fungi and facilitates bacterial entry into fungal tissues

    PubMed Central

    Spraker, Joseph E; Sanchez, Laura M; Lowe, Tiffany M; Dorrestein, Pieter C; Keller, Nancy P

    2016-01-01

    Ralstonia solanacearum is a globally distributed soil-borne plant pathogenic bacterium, which shares a broad ecological range with many plant- and soil-associated fungi. We sought to determine if R. solanacearum chemical communication directs symbiotic development of polymicrobial consortia. R. solanacearum produced a diffusible metabolite that induced conserved morphological differentiation in 34 species of fungi across three diverse taxa (Ascomycetes, Basidiomycetes and Zygomycetes). Fungi exposed to this metabolite formed chlamydospores, survival structures with thickened cell walls. Some chlamydospores internally harbored R. solanacearum, indicating a newly described endofungal lifestyle for this important plant pathogen. Using imaging mass spectrometry and peptidogenomics, we identified an undescribed lipopeptide, ralsolamycin, produced by an R. solanacearum non-ribosomal peptide synthetase-polyketide synthase hybrid. Inactivation of the hybrid non-ribosomal peptide synthetase-polyketide synthase gene, rmyA, abolished ralsolamycin synthesis. R. solanacearum mutants lacking ralsolamycin no longer induced chlamydospore development in fungal coculture and invaded fungal hyphae less well than wild-type. We propose that ralsolamycin contributes to the invasion of fungal hyphae and that the formation of chlamydospores may provide not only a specific niche for bacterial colonization but also enhanced survival for the partnering fungus. PMID:26943626

  11. Targeting the genital tract mucosa with a lipopeptide/recombinant adenovirus prime/boost vaccine induces potent and long-lasting CD8+ T cell immunity against herpes: importance of MyD88.

    PubMed

    Zhang, Xiuli; Dervillez, Xavier; Chentoufi, Aziz Alami; Badakhshan, Tina; Bettahi, Ilham; Benmohamed, Lbachir

    2012-11-01

    Targeting of the mucosal immune system of the genital tract with subunit vaccines has failed to induce potent and durable local CD8(+) T cell immunity, which is crucial for protection against many sexually transmitted viral pathogens, including HSV type 2 (HSV-2), which causes genital herpes. In this study, we aimed to investigate the potential of a novel lipopeptide/adenovirus type 5 (Lipo/rAdv5) prime/boost mucosal vaccine for induction of CD8(+) T cell immunity to protect the female genital tract from herpes. The lipopeptide vaccine and the rAdv5 vaccine express the immunodominant HSV-2 CD8(+) T cell epitope (gB(498-505)), and both were delivered intravaginally in the progesterone-induced B6 mouse model of genital herpes. Compared with mice immunized with the homologous lipopeptide/lipopeptide (Lipo/Lipo) vaccine, the Lipo/rAdv5 prime/boost immunized mice 1) developed potent and sustained HSV-specific CD8(+) T cells, detected in both the genital tract draining nodes and in the vaginal mucosa; 2) had significantly lower virus titers; 3) had decreased overt signs of genital herpes disease; and 4) did not succumb to lethal infection (p < 0.005) after intravaginal HSV-2 challenge. Polyfunctional CD8(+) T cells, producing IFN-γ, TNF-α, and IL-2 and exhibiting cytotoxic activity, were associated with protection (p < 0.005). The protective CD8(+) T cell response was significantly compromised in the absence of the adapter MyD88 (p = 0.0001). Taken together, these findings indicate that targeting of the vaginal mucosa with a Lipo/rAdv5 prime/boost vaccine elicits a potent, MyD88-dependent, and long-lasting mucosal CD8(+) T cell protective immunity against sexually transmitted herpes infection and disease.

  12. Fungal lipopeptide mating pheromones: a model system for the study of protein prenylation.

    PubMed Central

    Caldwell, G A; Naider, F; Becker, J M

    1995-01-01

    In a variety of fungal species, mating between haploid cells is initiated by the action of peptide pheromones. The identification and characterization of several fungal pheromones has revealed that they have common structural features classifying them as lipopeptides. In the course of biosynthesis, these pheromones undergo a series of posttranslational processing events prior to export. One common modification is the attachment of an isoprenoid group to the C terminus of the pheromone precursor. Genetic and biochemical investigations of this biosynthetic pathway have led to the elucidation of genes and enzymes which are responsible for isoprenylation of other polypeptides including the nuclear lamins, several vesicular transport proteins, and the oncogene product Ras. The alpha-factor of Saccharomyces cerevisiae serves as a model for studying the biosynthesis, export, and bioactivity of lipopeptide pheromones. In addition to being isoprenylated with a farnesyl group, the alpha-factor is secreted by a novel peptide export pathway utilizing a yeast homolog of the mammalian multidrug resistance P-glycoprotein. The identification of putative lipopeptide-encoding loci within other fungi, including the human immunodeficiency virus-associated opportunistic pathogen Cryptococcus neoformans and the plant pathogen Ustilago maydis, has stimulated much interest in understanding possible roles for pheromones in fungal proliferation and pathogenicity. Knowledge of variations within the processing, export, and receptor-mediated signal transduction pathways associated with different fungal lipopeptide pheromones will continue to provide insights into similar mechanisms which exist in higher eukaryotes. PMID:7565412

  13. Immunostimulation by Synthetic Lipopeptide-Based Vaccine Candidates: Structure-Activity Relationships

    PubMed Central

    Zaman, Mehfuz; Toth, Istvan

    2013-01-01

    Peptide-based vaccines offer several advantages over conventional whole organism or protein approaches by offering improved purity and specificity in inducing immune response. However, peptides alone are generally non-immunogenic. Concerns remain about the toxicity of adjuvants which are critical for immunogenicity of synthetic peptides. The use of lipopeptides in peptide vaccines is currently under intensive investigation because potent immune responses can be generated without the use of adjuvant (thus are self-adjuvanting). Several lipopeptides derived from microbial origin, and their synthetic versions or simpler fatty acid moieties impart this self-adjuvanting activity by signaling via Toll-like receptor 2 (TLR2). Engagement of this innate immune receptor on antigen-presenting cell leads to the initiation and development of potent immune responses. Therefore optimization of lipopeptides to enhance TLR2-mediated activation is a promising strategy for vaccine development. Considerable structure-activity relationships that determine TLR2 binding and consequent stimulation of innate immune responses have been investigated for a range of lipopeptides. In this mini review we address the development of lipopeptide vaccines, mechanism of TLR2 recognition, and immune activation. An overview is provided of the best studied lipopeptide vaccine systems. PMID:24130558

  14. Genetic and Functional Characterization of Cyclic Lipopeptide White-Line-Inducing Principle (WLIP) Production by Rice Rhizosphere Isolate Pseudomonas putida RW10S2

    PubMed Central

    Rokni-Zadeh, Hassan; Li, Wen; Sanchez-Rodriguez, Aminael; Sinnaeve, Davy; Rozenski, Jef; Martins, José C.

    2012-01-01

    The secondary metabolite mediating the GacS-dependent growth-inhibitory effect exerted by the rice rhizosphere isolate Pseudomonas putida RW10S2 on phytopathogenic Xanthomonas species was identified as white-line-inducing principle (WLIP), a member of the viscosin group of cyclic lipononadepsipeptides. WLIP producers are commonly referred to by the taxonomically invalid name “Pseudomonas reactans,” based on their capacity to reveal the presence of a nearby colony of Pseudomonas tolaasii by inducing the formation of a visible precipitate (“white line”) in agar medium between both colonies. This phenomenon is attributed to the interaction of WLIP with a cyclic lipopeptide of a distinct structural group, the fungitoxic tolaasin, and has found application as a diagnostic tool to identify tolaasin-producing bacteria pathogenic to mushrooms. The genes encoding the WLIP nonribosomal peptide synthetases WlpA, WlpB, and WlpC were identified in two separate genomic clusters (wlpR-wlpA and wlpBC) with an operon organization similar to that of the viscosin, massetolide, and entolysin biosynthetic systems. Expression of wlpR is dependent on gacS, and the encoded regulator of the LuxR family (WlpR) activates transcription of the biosynthetic genes and the linked export genes, which is not controlled by the RW10S2 quorum-sensing system PmrR/PmrI. In addition to linking the known phenotypes of white line production and hemolytic activity of a WLIP producer with WLIP biosynthesis, additional properties of ecological relevance conferred by WLIP production were identified, namely, antagonism against Xanthomonas and involvement in swarming and biofilm formation. PMID:22544260

  15. Histidine-Based Lipopeptides Enhance Cleavage of Nucleic Acids: Interactions with DNA and Hydrolytic Properties.

    PubMed

    Bélières, M; Déjugnat, C; Chouini-Lalanne, N

    2015-12-16

    Interaction studies and cleavage activity experiments were carried out between plasmid DNA and a series of histidine-based lipopeptides. Specific fluorescent probes (ethidium bromide, Hoechst 33342, and pyrene) were used to monitor intercalation, minor groove binding, and self-assembly of lipopeptides, respectively. Association between DNA and lipopeptides was thus evidenced, highlighting the importance of both histidine and hydrophobic tail in the interaction process. DNA cleavage in the presence of lipopeptides was then detected by gel electrophoresis and quantified, showing the importance of histidine and the involvement of its side-chain imidazole in the hydrolysis mechanism. These systems could then be developed as synthetic nucleases while raising concern of introducing histidine in the design of lipopeptide-based transfection vectors.

  16. Purification and antitumour activity of a lipopeptide biosurfactant produced by Bacillus natto TK-1.

    PubMed

    Cao, Xiao-Hong; Liao, Zhen-Yu; Wang, Chun-Ling; Cai, Ping; Yang, Wen-Yan; Lu, Mei-Fang; Huang, Guo-Wei

    2009-02-01

    An antitumour lipopeptide biosurfactant purified from Bacillus natto TK-1 was able to inhibit the proliferation of MCF-7 human breast-cancer cells in a dose- and time-dependent manner. The activity of lactate dehydrogenase release showed no significant difference between MCF-7 cells treated with lipopeptide and untreated controls. The antitumour activity of the lipopeptide in MCF-7 cells was associated with cell apoptosis determined by typical morphological changes and sub-G(1) peak in cell growth-phase distribution. The cell cycle was arrested at G(2)/M phase. In addition, the caspase activity assay revealed that lipopeptide-induced apoptosis in MCF-7 cells was associated with caspase 3.

  17. Lipopeptide biosurfactant viscosin enhances dispersal of Pseudomonas fluorescens SBW25 biofilms.

    PubMed

    Bonnichsen, Lise; Bygvraa Svenningsen, Nanna; Rybtke, Morten; de Bruijn, Irene; Raaijmakers, Jos M; Tolker-Nielsen, Tim; Nybroe, Ole

    2015-12-01

    Pseudomonads produce several lipopeptide biosurfactants that have antimicrobial properties but that also facilitate surface motility and influence biofilm formation. Detailed studies addressing the significance of lipopeptides for biofilm formation and architecture are rare. Hence, the present study sets out to determine the specific role of the lipopeptide viscosin in Pseudomonas fluorescens SBW25 biofilm formation, architecture and dispersal, and to relate viscA gene expression to viscosin production and effect. Initially, we compared biofilm formation of SBW25 and the viscosin-deficient mutant strain SBW25ΔviscA in static microtitre assays. These experiments demonstrated that viscosin had little influence on the amount of biofilm formed by SBW25 during the early stages of biofilm development. Later, however, SBW25 formed significantly less biofilm than SBW25ΔviscA. The indication that viscosin is involved in biofilm dispersal was confirmed by chemical complementation of the mutant biofilm. Furthermore, a fluorescent bioreporter showed that viscA expression was induced in biofilms 4 h prior to dispersal. Subsequent detailed studies of biofilms formed in flow cells for up to 5 days revealed that SBW25 and SBW25ΔviscA developed comparable biofilms dominated by well-defined, mushroom-shaped structures. Carbon starvation was required to obtain biofilm dispersal in this system. Dispersal of SBW25 biofilms was significantly greater than of SBW25ΔviscA biofilms after 3 h and, importantly, carbon starvation strongly induced viscA expression, in particular for cells that were apparently leaving the biofilm. Thus, the present study points to a role for viscosin-facilitated motility in dispersal of SBW25 biofilms.

  18. A recombinant lipoprotein containing an unsaturated fatty acid activates NF-kappaB through the TLR2 signaling pathway and induces a differential gene profile from a synthetic lipopeptide.

    PubMed

    Leng, Chih-Hsiang; Chen, Hsin-Wei; Chang, Li-Sheng; Liu, Hsueh-Hung; Liu, Hsin-Yu; Sher, Yuh-Pyng; Chang, Yu-Wen; Lien, Shu-Pei; Huang, Tzu-Yi; Chen, Mei-Yu; Chou, Ai-Hsiang; Chong, Pele; Liu, Shih-Jen

    2010-07-01

    The lipid moiety of a novel recombinant lipoprotein, which contains a dengue virus envelope protein domain 3, rlipo-D1E3, has been shown to activate antigen-presenting cells (APCs) as an intrinsic adjuvant. Because the lipid moiety of rlipo-D1E3 contains an unsaturated fatty acid, it is unclear if the receptor usage by bacterially derived lipoproteins is the same as that of the synthetic lipopeptide palmitoyl-3-Cys-Ser-(Lys)(4) (Pam3). In the present study, we show that the rlipo-D1E3 lipoprotein can induce the activation of spleen cells and bone marrow-derived dendritic cells (BM-DCs) in wild-type and TLR4-deficient mice, but not in TLR2(-/-) mice. After analyzing the co-receptor usage of TLR2 using TLR1(-/-) or TLR6(-/-) mice, the TLR2 signaling triggered by rlipo-D1E3 and Pam3 could use either TLR1 or TLR6 as a co-receptor. Analysis of the MAPK signaling pathway revealed that rlipo-D1E3 could initiate the phosphorylation of p38, ERK1/2 and JNK1/2 earlier than the synthetic lipopeptide. In addition, the expression levels of IL-23, IL-27 and MIP-1 alpha in BM-DCs stimulated by rlipo-D1E3 were higher than the expression levels in BM-DCs stimulated by Pam3. Taken together, these results demonstrate that different TLR2 ligands can promote various immune responses by inducing different levels of biological cytokines and chemokines.

  19. Production and identification of iturin A lipopeptide from Bacillus methyltrophicus TEB1 for control of Phoma tracheiphila.

    PubMed

    Kalai-Grami, Leila; Karkouch, Ines; Naili, Omar; Slimene, Imen Ben; Elkahoui, Salem; Zekri, Roudaina Ben; Touati, Ines; Mnari-Hattab, Monia; Hajlaoui, Mohamed Rabeh; Limam, Ferid

    2016-08-01

    A lipopeptide-producing endophytic Bacillus methyltrophicus TEB1 strain exhibited potent antifungal activity against Phoma tracheiphila. Lipopeptide production started at the early growth phase plateaued after 36 h of culture where it reduced the mycelium growth by 80%. The crude lipopeptide extract harvested at the stationary phase efficiently inhibited the growth of P. tracheiphila mycelium and MIC values displaying 50 and 90% inhibition of conidia germination were around 47.5 and 100 μg ml(-1) , respectively. Increasing lipopeptide extract till 3 mg ml(-1) induced 10% swelling and 3% crumbling of P. tracheiphila conidia whereas 5 mg ml(-1) induced 40% swelling and 20% crumbling. Mass spectrometry analysis of the lipopeptide extract indicated that surfactin production took place from 12 to 20 h, iturin A from 16 to 72 h, and fengycin from 12 to 72 h and that the main active compound against P. tracheiphila was identified as C15 iturin A lipopeptide. Iturin A appeared as a potential biological control agent able to substitute the currently used chemical pesticides in agriculture.

  20. Toll-like receptor 2- and 6-mediated stimulation by macrophage-activating lipopeptide 2 induces lipopolysaccharide (LPS) cross tolerance in mice, which results in protection from tumor necrosis factor alpha but in only partial protection from lethal LPS doses.

    PubMed

    Deiters, Ursula; Gumenscheimer, Marina; Galanos, Chris; Mühlradt, Peter F

    2003-08-01

    Patients or experimental animals previously exposed to lipopolysaccharide (LPS) become tolerant to further LPS challenge. We investigated the potential of the macrophage-activating lipopeptide 2 (MALP-2) to induce in vivo cross tolerance to tumor necrosis factor alpha (TNF-alpha) and LPS. MALP-2-induced tolerance could be of practical interest, as MALP-2 proved much less pyrogenic in rabbits than LPS. Whereas LPS signals via Toll-like receptor 4 (TLR4), MALP-2 uses TLR2 and TLR6. LPS-mediated cytokine release was studied in mice pretreated with intraperitoneal injections of MALP-2. No biologically active TNF-alpha could be detected in the serum of MALP-2-treated animals when challenged with LPS 24 or 72 h later, whereas suppression of LPS-dependent interleukin (IL)-6 lasted for only 24 h. Protection from lethal TNF-alpha shock was studied in galactosamine-treated mice. Dose dependently, MALP-2 prevented death from lethal TNF-alpha doses in TLR4(-/-) but not in TLR2(-/-) mice, with protection lasting from 5 to 24 h. To assay protection from LPS, mice were pretreated with MALP-2 doses of up to 10 micro g. Five and 24 h later, the animals were simultaneously sensitized and challenged by intravenous coinjection of galactosamine and a lethal dose of 50 ng of LPS. There was only limited protection (four of seven mice survived) when mice were challenged 5 h after MALP-2 pretreatment, and no protection when mice were challenged at later times. The high effectiveness of MALP-2 in suppressing TNF-alpha, the known ways of biological inactivation, and low pyrogenicity make MALP-2 a potential candidate for clinical use.

  1. Staphylococcal superantigen-like protein 3 binds to the Toll-like receptor 2 extracellular domain and inhibits cytokine production induced by Staphylococcus aureus, cell wall component, or lipopeptides in murine macrophages.

    PubMed

    Yokoyama, Ryosuke; Itoh, Saotomo; Kamoshida, Go; Takii, Takemasa; Fujii, Satoshi; Tsuji, Tsutomu; Onozaki, Kikuo

    2012-08-01

    Staphylococcal superantigen-like proteins (SSLs) are a family of exoproteins sharing structural similarity with superantigens, but no superantigenic activity. Corresponding host target proteins or receptors against a portion of SSLs in the family have been identified. In this study, we show that SSL3 specifically binds to Toll-like receptor 2 (TLR2) and inhibits the stimulation of macrophages by TLR2 ligands. An approximately 100-kDa protein was recovered by using recombinant His-tagged SSL3-conjugated Sepharose from the lysate of porcine spleen, and the protein was identified as porcine TLR2 by peptide mass fingerprinting analysis. The SSL3-conjugated Sepharose recovered human and mouse TLR2 but not TLR4 from human neutrophils and mouse macrophage RAW 264.7 cells, as well as a recombinant TLR2 extracellular domain chimera protein. The production levels of interleukin 12 (IL-12) from mouse macrophages treated with heat-killed Staphylococcus aureus and of tumor necrosis factor alpha (TNF-α) from RAW 264.7 cells induced by peptidoglycan or lipopeptide TLR2 ligands were strongly suppressed in the presence of SSL3. The mutation of consensus sialic acid-containing glycan-binding residues in SSL3 did not abrogate the binding ability to TLR2 or inhibitory activity on TLR2, indicating that the interaction of SSL3 with TLR2 was independent of the sialic acid-containing glycan-binding residues. These findings demonstrate that SSL3 is able to bind the extracellular domain of TLR2 and interfere with TLR2 function. The present study provides a novel mechanism of SSL3 in immune evasion of S. aureus via interfering with its recognition by innate immune cells.

  2. Removal of heavy metals from aqueous solution by lipopeptides and lipopeptides modified Na-montmorillonite.

    PubMed

    Zhu, Zhen; Gao, Chao; Wu, Yanliang; Sun, Lifei; Huang, Xiaolei; Ran, Wei; Shen, Qirong

    2013-11-01

    The removal of Cu(2+), Zn(2+), Cd(2+), Pb(2+) and Hg(2+) from aqueous solution by lipopeptides produced from solid-state fermentation (LPSSF) and LPSSF modified Na-montmorillonite clays (LPSSF/Na-MMT) was investigated. The results showed that the LPSSF had certain adsorption capability for the metal ions and the modification of Na-MMT with LPSSF at a weight ratio of 1:50 (LPSSF:Na-MMT) had the best adsorption capacity and adsorption rate. The adsorption of heavy metal ion on these adsorbents was monolayer sorption. And the rate limiting step of the adsorption process was thought as chemical sorption. The N-C-O and CC/CN groups of the LPSSF are the functional groups that were responsible for complexing the metal ions. The desorption rate of metal ions reached over 80% at 500 mg/L of LPSSF. The LPSSF/Na-MMT (1:50) was reusable and performed well in the complex system, indicating its potential application in wastewater treatment.

  3. Lipopeptide surfactants: Production, recovery and pore forming capacity.

    PubMed

    Inès, Mnif; Dhouha, Ghribi

    2015-09-01

    Lipopeptides are microbial surface active compounds produced by a wide variety of bacteria, fungi and yeast. They are characterized by highly structural diversity and have the ability to decrease the surface and interfacial tension at the surface and interface, respectively. Surfactin, iturin and fengycin of Bacillus subtilis are among the most studied lipopeptides. This review will present the main factors encountering lipopeptides production along with the techniques developed for their extraction and purification. Moreover, we will discuss their ability to form pores and destabilize biological membrane permitting their use as antimicrobial, hemolytic and antitumor agents. These open great potential applications in biomediacal, pharmaceutic and agriculture fields.

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

    PubMed Central

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

    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

  5. Human filarial Wolbachia lipopeptide directly activates human neutrophils in vitro.

    PubMed

    Tamarozzi, F; Wright, H L; Johnston, K L; Edwards, S W; Turner, J D; Taylor, M J

    2014-10-01

    The host inflammatory response to the Onchocerca volvulus endosymbiont, Wolbachia, is a major contributing factor in the development of chronic pathology in humans (onchocerciasis/river blindness). Recently, the toll-like pattern recognition receptor motif of the major inflammatory ligands of filarial Wolbachia, membrane-associated diacylated lipoproteins, was functionally defined in murine models of pathology, including mediation of neutrophil recruitment to the cornea. However, the extent to which human neutrophils can be activated in response to this Wolbachia pattern recognition motif is not known. Therefore, the responses of purified peripheral blood human neutrophils to a synthetic N-terminal diacylated lipopeptide (WoLP) of filarial Wolbachia peptidoglycan-associated lipoprotein (PAL) were characterized. WoLP exposure led to a dose-dependent activation of healthy, human neutrophils that included gross morphological alterations and modulation of surface expressed integrins involved in tethering, rolling and extravasation. WoLP exposure induced chemotaxis but not chemokinesis of neutrophils, and secretion of the major neutrophil chemokine, interleukin 8. WoLP also induced and primed the respiratory burst, and enhanced neutrophil survival by delay of apoptosis. These results indicate that the major inflammatory motif of filarial Wolbachia lipoproteins directly activates human neutrophils in vitro and promotes a molecular pathway by which human neutrophils are recruited to sites of Onchocerca parasitism.

  6. Process development and intensification for enhanced production of Bacillus lipopeptides.

    PubMed

    Rangarajan, Vivek; Clarke, Kim G

    2015-01-01

    The growing interest in Bacillus lipopeptides for high-value applications has driven process design, development and optimization for enhanced lipopeptide production. Traditional optimization approaches have been directed towards improving the overall titres by modification of media components and environmental parameters, almost exclusively in submerged cultures. Carbon and nitrogen sources, trace elements and oxygen availability have all been demonstrated to exhibit significant influences on lipopeptide yield, productivity and selectivity. This insight into process-linked kinetics, especially selectivity, has led to the introduction of novel process intensification and integration strategies which further promote process efficiency, and which include foam fractionation, inverse fluidization, rotating disc contacting and microfiltration with recycle. These strategies have not only transformed the production capabilities, but have also successfully integrated upstream production with downstream purification through cell retention and in situ product removal. This review analyses and critically discusses the impact of process conditions and process optimization strategies for improving lipopeptide production kinetics, specifically highlighting the emerging trend of process intensification and integration strategies and further, proposes a heuristic route to enhance lipopeptide production.

  7. Epithelial and Stromal Cells of Bovine Endometrium Have Roles in Innate Immunity and Initiate Inflammatory Responses to Bacterial Lipopeptides In Vitro via Toll-Like Receptors TLR2, TLR1, and TLR6

    PubMed Central

    Turner, Matthew L.; Cronin, James G.; Healey, Gareth D.

    2014-01-01

    Bacteria often infect the endometrium of cattle to cause endometritis, uterine disease, and infertility. Lipopeptides are commonly found among bacteria and are detected by the Toll-like receptor (TLR) cell surface receptor TLR2 on immune cells. Heterodimers of TLR2 with TLR1 or TLR6 activate MAPK and nuclear factor-κB intracellular signaling pathways to stimulate inflammatory responses. In the endometrium, epithelial and stromal cells are the first to encounter invading bacteria, so the present study explored whether endometrial cells can also mount inflammatory responses to bacterial lipopeptides via TLRs. The supernatants of pure populations of primary bovine endometrial epithelial and stromal cells accumulated the cytokine IL-6 and the chemokine IL-8 in response to triacylated or diacylated bacterial lipopeptides. The accumulation of IL-6 and IL-8 in response to triacylated lipopeptides was reduced by small interfering RNA targeting TLR2 or TLR1 but not TLR6, whereas cellular responses to diacylated lipopeptide were reduced by small interfering RNA targeting TLR2, TLR1, or TLR6. Both lipopeptides induced rapid phosphorylation of ERK1/2, p38, and nuclear factor-κB in endometrial cells, and inhibitors of ERK1/2 or p38 limited the accumulation of IL-6. The ovarian steroids estradiol and progesterone had little impact on inflammatory responses to lipopeptides. The endometrial epithelial and stromal cell responses to lipopeptides via TLR2, TLR1, and TLR6 provide a mechanism linking a wide range of bacterial infections to inflammation of the endometrium. PMID:24437488

  8. Epithelial and stromal cells of bovine endometrium have roles in innate immunity and initiate inflammatory responses to bacterial lipopeptides in vitro via Toll-like receptors TLR2, TLR1, and TLR6.

    PubMed

    Turner, Matthew L; Cronin, James G; Healey, Gareth D; Sheldon, Iain Martin

    2014-04-01

    Bacteria often infect the endometrium of cattle to cause endometritis, uterine disease, and infertility. Lipopeptides are commonly found among bacteria and are detected by the Toll-like receptor (TLR) cell surface receptor TLR2 on immune cells. Heterodimers of TLR2 with TLR1 or TLR6 activate MAPK and nuclear factor-κB intracellular signaling pathways to stimulate inflammatory responses. In the endometrium, epithelial and stromal cells are the first to encounter invading bacteria, so the present study explored whether endometrial cells can also mount inflammatory responses to bacterial lipopeptides via TLRs. The supernatants of pure populations of primary bovine endometrial epithelial and stromal cells accumulated the cytokine IL-6 and the chemokine IL-8 in response to triacylated or diacylated bacterial lipopeptides. The accumulation of IL-6 and IL-8 in response to triacylated lipopeptides was reduced by small interfering RNA targeting TLR2 or TLR1 but not TLR6, whereas cellular responses to diacylated lipopeptide were reduced by small interfering RNA targeting TLR2, TLR1, or TLR6. Both lipopeptides induced rapid phosphorylation of ERK1/2, p38, and nuclear factor-κB in endometrial cells, and inhibitors of ERK1/2 or p38 limited the accumulation of IL-6. The ovarian steroids estradiol and progesterone had little impact on inflammatory responses to lipopeptides. The endometrial epithelial and stromal cell responses to lipopeptides via TLR2, TLR1, and TLR6 provide a mechanism linking a wide range of bacterial infections to inflammation of the endometrium.

  9. Evaluation of a lipopeptide biosurfactant from Bacillus natto TK-1 as a potential source of anti-adhesive, antimicrobial and antitumor activities

    PubMed Central

    Cao, Xiao-Hong; Liao, Zhen-Yu; Wang, Chun-Ling; Yang, Wen-Yan; Lu, Mei-Fang

    2009-01-01

    A lipopeptide biosurfactant produced by Bacillus natto TK-1 has a strong surface activity. The biosurfactant was found to be an anti-adhesive agent against several bacterial strains, and also showed a broad spectrum of antimicrobial activity. The biosurfactant induced a significant reduction in tumor cells viability in a dose-dependent manner. PMID:24031375

  10. A Novel Lipopeptide from Skin Commensal Activates TLR2/CD36-p38 MAPK Signaling to Increase Antibacterial Defense against Bacterial Infection

    PubMed Central

    Li, Dongqing; Lei, Hu; Li, Zhiheng; Li, Hongquan; Wang, Yue; Lai, Yuping

    2013-01-01

    Staphylococcus epidermidis (S.epidermidis) plays important protective roles by directly producing or by stimulating hosts to produce antimicrobial peptides (AMPs) against pathogenic infections. Although several AMPs from S.epidermidis have been identified, molecules that stimulate hosts to produce AMPs remain largly unknown. Here we demonstrate that a new lipopeptide (named LP01) purified from S.epidermidis culture media has a unique structure with heneicosanoic acid (21 carbons) binding to lysine11 of a peptide chain. In vitro LP01 increased the expression of β-defensin 2(hBD2) and hBD3 in neonatal human epidermal keratinocytes(NHEK), leading to increased capacity of cell lysates to inhibit the growth of S.aureus. In vivo LP01 induced the expression of mouse β-defensin 4(mBD4) to decrease the survival of local S.aureus in skin and systemic S.aureus survival in liver. The induction of beta-defensins by LP01 was dependent on TLR2 as Tlr2-deficient mice had decreased mBD4. Furthermore, knockdown of CD36 decreased the expression of hBD2 and hBD3, and p38 MAPK inhibitor significantly inhibited the expression of hBDs induced by LP01.Taken together, these findings demonstrate that lipopeptide LP01 from normal commensal S.epidermidis increases antimicrobial peptide hBD2 and hBD3 expression via the activation of TLR2/CD36-p38 MAPK, thus enhancing antimicrobial defense against pathogenic infections. PMID:23472173

  11. A lipopeptide facilitate induction of Mycobacterium leprae killing in host cells.

    PubMed

    Maeda, Yumi; Tamura, Toshiki; Fukutomi, Yasuo; Mukai, Tetsu; Kai, Masanori; Makino, Masahiko

    2011-11-01

    Little is known of the direct microbicidal activity of T cells in leprosy, so a lipopeptide consisting of the N-terminal 13 amino acids lipopeptide (LipoK) of a 33-kD lipoprotein of Mycobacterium leprae, was synthesized. LipoK activated M. leprae infected human dendritic cells (DCs) to induce the production of IL-12. These activated DCs stimulated autologous CD4+ or CD8+ T cells towards type 1 immune response by inducing interferon-gamma secretion. T cell proliferation was also evident from the CFSE labeling of target CD4+ or CD8+ T cells. The direct microbicidal activity of T cells in the control of M. leprae multiplication is not well understood. The present study showed significant production of granulysin, granzyme B and perforin from these activated CD4+ and CD8+ T cells when stimulated with LipoK activated, M. leprae infected DCs. Assessment of the viability of M. leprae in DCs indicated LipoK mediated T cell-dependent killing of M. leprae. Remarkably, granulysin as well as granzyme B could directly kill M. leprae in vitro. Our results provide evidence that LipoK could facilitate M. leprae killing through the production of effector molecules granulysin and granzyme B in T cells.

  12. The Antimicrobial Compound Xantholysin Defines a New Group of Pseudomonas Cyclic Lipopeptides

    PubMed Central

    Li, Wen; Rokni-Zadeh, Hassan; De Vleeschouwer, Matthias; Ghequire, Maarten G. K.; Sinnaeve, Davy; Xie, Guan-Lin; Rozenski, Jef; Madder, Annemieke; Martins, José C.; De Mot, René

    2013-01-01

    The rhizosphere isolate Pseudomonas putida BW11M1 produces a mixture of cyclic lipopeptide congeners, designated xantholysins. Properties of the major compound xantholysin A, shared with several other Pseudomonas lipopeptides, include antifungal activity and toxicity to Gram-positive bacteria, a supportive role in biofilm formation, and facilitation of surface colonization through swarming. Atypical is the lipopeptide’s capacity to inhibit some Gram-negative bacteria, including several xanthomonads. The lipotetradecadepsipeptides are assembled by XtlA, XtlB and XtlC, three co-linearly operating non-ribosomal peptide synthetases (NRPSs) displaying similarity in modular architecture with the entolysin-producing enzymes of the entomopathogenic Pseudomonas entomophila L48. A shifted serine-incorporating unit in the eight-module enzyme XtlB elongating the central peptide moiety not only generates an amino acid sequence differing at several equivalent positions from entolysin, but also directs xantholysin’s macrocyclization into an octacyclic structure, distinct from the pentacyclic closure in entolysin. Relaxed fatty acid specificity during lipoinitiation by XtlA (acylation with 3-hydroxydodec-5-enoate instead of 3-hydroxydecanoate) and for incorporation of the ultimate amino acid by XtlC (valine instead of isoleucine) account for the production of the minor structural variants xantholysin C and B, respectively. Remarkably, the genetic backbones of the xantholysin and entolysin NRPS systems also bear pronounced phylogenetic similarity to those of the P. putida strains PCL1445 and RW10S2, albeit generating the seemingly structurally unrelated cyclic lipopeptides putisolvin (undecapeptide containing a cyclotetrapeptide) and WLIP (nonapeptide containing a cycloheptapeptide), respectively. This similarity includes the linked genes encoding the cognate LuxR-family regulator and tripartite export system components in addition to individual modules of the NRPS enzymes, and

  13. Infection-enhancing lipopeptides do not improve intranasal immunization of cotton rats with a delta-G candidate live-attenuated human respiratory syncytial virus vaccine.

    PubMed

    Tien Nguyen, D; Boes, Jolande; van Amerongen, Geert; van Remmerden, Yvonne; Yüksel, Selma; Guichelaar, Teun; Osterhaus, Albert D M E; de Swart, Rik L

    2013-12-01

    Development of live-attenuated human respiratory syncytial virus (HRSV) vaccines has proven to be difficult. Several vaccine candidates were found to be over-attenuated and displayed limited immunogenicity. Recently, we identified three synthetic cationic lipopeptides that enhanced paramyxovirus infections in vitro. The infection enhancement proved to be mediated by enhanced virus binding to target cells. We hypothesized that these lipopeptides can be used as adjuvants to promote immune responses induced by live-attenuated paramyxovirus vaccines. This hypothesis was tested in a vaccination and challenge model in cotton rats, using a previously described recombinant live-attenuated candidate HRSV vaccine lacking the gene encoding the G glycoprotein (rHRSVΔG). Surprisingly, intranasal vaccination of cotton rats with rHRSVΔG formulated in infection-enhancing lipopeptides resulted in reduced virus loads in nasopharyngeal lavages, reduced seroconversion levels and reduced protection from wild-type HRSV challenge. In conclusion, we were unable to demonstrate the feasibility of lipopeptides as adjuvants for a candidate live-attenuated HRSV vaccine in the cotton rat model.

  14. Short cationic lipopeptides as effective antibacterial agents: Design, physicochemical properties and biological evaluation.

    PubMed

    Azmi, Fazren; Elliott, Alysha G; Marasini, Nirmal; Ramu, Soumya; Ziora, Zyta; Kavanagh, Angela M; Blaskovich, Mark A T; Cooper, Matthew A; Skwarczynski, Mariusz; Toth, Istvan

    2016-05-15

    The spread of drug-resistant bacteria has imparted a sense of urgency in the search for new antibiotics. In an effort to develop a new generation of antibacterial agents, we have designed de novo charged lipopeptides inspired by natural antimicrobial peptides. These short lipopeptides are composed of cationic lysine and hydrophobic lipoamino acids that replicate the amphiphilic properties of natural antimicrobial peptides. The resultant lipopeptides were found to self-assemble into nanoparticles. Some were effective against a variety of Gram-positive bacteria, including strains resistant to methicillin, daptomycin and/or vancomycin. The lipopeptides were not toxic to human kidney and liver cell lines and were highly resistant to tryptic degradation. Transmission electron microscopy analysis of bacteria cells treated with lipopeptide showed membrane-damage and lysis with extrusion of cytosolic contents. With such properties in mind, these lipopeptides have the potential to be developed as new antibacterial agents against drug-resistant Gram-positive bacteria.

  15. Ecological and mechanistic insights into the direct and indirect antimicrobial properties of Bacillus subtilis lipopeptides on plant pathogens.

    PubMed

    Falardeau, J; Wise, C; Novitsky, L; Avis, T J

    2013-07-01

    Members of the genus Bacillus produce a wide variety of antimicrobial compounds. Cyclic lipopeptides (CLP) produced by Bacillus subtilis strains have been shown to protect host plants from a numbers of pathogens. The representative families of these CLP (surfactins, fengycins, and iturins) share a polypeptide ring linked to a lipid tail of varying length. CLP provide plant protection through a variety of unique mechanisms. Members of the surfactin and fengycin families elicit induced systemic resistance in certain host plants, and they also function by directly affecting the biological membranes of bacterial and fungal pathogens, mainly resulting in membrane pore formation. Specific pore forming mechanisms differ between CLP families, causing differential activities. CLP also may aid in enhanced B. subtilis colonization of the plant environment in addition to potentially preventing the adhesion of competitive microorganisms. Several recent studies have highlighted the control of plant pathogens by CLP-producing B. subtilis strains. Strong ecological advantages through multifaceted activities of CLP provide these strains with immense promise in controlling pathogens in a variety of plant ecosystems.

  16. Cellular responses of the late blight pathogen Phytophthora infestans to cyclic lipopeptide surfactants and their dependence on G proteins.

    PubMed

    van de Mortel, Judith E; Tran, Ha; Govers, Francine; Raaijmakers, Jos M

    2009-08-01

    Oomycete pathogens cause major yield losses for many crop plants, and their control depends heavily on agrochemicals. Cyclic lipopeptides (CLPs) were recently discovered as a new class of natural compounds with strong activities against oomycetes. The CLP massetolide A (Mass A), produced by Pseudomonas fluorescens, has zoosporicidal activity, induces systemic resistance, and reduces late blight in tomato. To gain further insight into the modes of action of CLPs, the effects of Mass A on pore formation, mycelial growth, sporangium formation, and zoospore behavior were investigated, as was the involvement of G proteins in the sensitivity of Phytophthora infestans to Mass A. The results showed that Mass A induced the formation of transmembrane pores with an estimated size of between 1.2 and 1.8 nm. Dose-response experiments revealed that zoospores were the most sensitive to Mass A, followed by mycelium and cysts. Mass A significantly reduced sporangium formation and caused increased branching and swelling of hyphae. At relatively low concentrations, Mass A induced encystment of zoospores. It had no effect on the chemotactic response of zoospores but did adversely affect zoospore autoaggregation. A loss-of-function transformant of P. infestans lacking the G-protein alpha subunit was more sensitive to Mass A, whereas a gain-of-function transformant required a higher Mass A concentration to interfere with zoospore aggregation. Results indicate that Mass A disturbs various developmental stages in the life cycle of P. infestans and suggest that the cellular responses of P. infestans to this CLP are, in part, dependent on G-protein signaling.

  17. Mebamamides A and B, Cyclic Lipopeptides Isolated from the Green Alga Derbesia marina.

    PubMed

    Iwasaki, Arihiro; Ohno, Osamu; Sumimoto, Shinpei; Matsubara, Teruhiko; Shimada, Satoshi; Sato, Toshinori; Suenaga, Kiyotake

    2015-04-24

    Mebamamides A and B, new lipopeptides with four d-amino acid residues and a 3,8-dihydroxy-9-methyldecanoic acid residue, were isolated from the green alga Derbesia marina. Their gross structures were elucidated by spectroscopic and ESI-ITMS analyses. The absolute configurations except for the two leucines were revealed based on chiral-phase HPLC analyses of the acid hydrolysate and a modified Mosher's method. A distinction between D-Leu and L-Leu in the sequence was established by the application of a dansyl-Edman method to the partial acid hydrolysate. Mebamamide A did not exhibit any growth inhibitory activity against HeLa and HL60 cells at 10 μM, and mebamamide B did not exhibit any growth inhibitory activity against those cells at 100 μM. Additionally, it was suggested that mebamamide B induced the differentiation of HL60 cells into macrophage-like cells at 100 μM.

  18. A54145, a new lipopeptide antibiotic complex: discovery, taxonomy, fermentation and HPLC.

    PubMed

    Boeck, L D; Papiska, H R; Wetzel, R W; Mynderse, J S; Fukuda, D S; Mertz, F P; Berry, D M

    1990-06-01

    A54145 is a complex of new lipopeptide antibiotics that inhibits Gram-positive bacteria and acts as a growth promotant for broiler chicks. Eight factors; A, B, C, D, E, F, A1 and B1; have been isolated and characterized. They contain four similar peptide nuclei, each of which is acylated with either an 2-decanoyl, n-decanoyl, or undecanoyl side chain. Taxonomic studies ascertained that the producing microorganism was a strain of Streptomyces fradiae. Fermentation studies determined that superior antibiotic yields were obtained in stirred bioreactors in a soybean flour-molasses medium employing a continuous glucose feed. These findings, interwoven with the selection of hyper-productive mutants, increased fermentation yields from less than 50 micrograms/ml to more than 1 mg/ml. An analytical HPLC system was developed for the identification and subsequent quantitation of each factor of the A54145 complex.

  19. Cationic Net Charge and Counter Ion Type as Antimicrobial Activity Determinant Factors of Short Lipopeptides.

    PubMed

    Greber, Katarzyna E; Dawgul, Malgorzata; Kamysz, Wojciech; Sawicki, Wieslaw

    2017-01-01

    To get a better insight into the antimicrobial potency of short cationic lipopeptides, 35 new entities were synthesized using solid phase peptide strategy. All newly obtained lipopeptides were designed to be positively charged from +1 to +4. This was achieved by introducing basic amino acid - lysine - into the lipopeptide structure and had a hydrophobic fatty acid chain attached. Lipopeptides were subjected to microbiological tests using reference strains of Gram-negative bacteria: Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris, Pseudomonas aeruginosa, Gram-positive bacteria: Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis, Enterococcus faecalis, and fungi: Candida albicans, Candida tropicalis, Aspergillus brasiliensis. The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and minimal fungicidal concentration (MFC) were established for each strain. The toxicity toward human cells was determined by hemolysis tests via minimum hemolytic concentration (MHC) determination. The effect of the trifluoroacetic acid (TFA) counter ion on the antimicrobial activity of lipopeptides was also examined by its removing and performing the antimicrobial tests using counter ion-free compounds. The study shows that lipopeptides are more potent against Gram-positive than Gram-negative strains. It was revealed that positive charge equals at least +2 is a necessary condition to observe significant antimicrobial activity, but only when it is balanced with a proper length of hydrophobic fatty acid chain. The hemolytic activity of lipopeptides strongly depends on amino acid composition of the hydrophilic portion of the molecule as well as fatty acid chain length. Compounds endowed with a greater positive charge were more toxic to human erythrocytes. This should be considered during new lipopeptide molecules design. Our studies also revealed the TFA counter ion has no significant effect on the antimicrobial behavior of cationic

  20. Isolation and characterization of diverse antimicrobial lipopeptides produced by Citrobacter and Enterobacter

    PubMed Central

    2013-01-01

    Background Increasing multidrug-resistance in bacteria resulted in a greater need to find alternative antimicrobial substances that can be used for clinical applications or preservation of food and dairy products. Research on antimicrobial peptides including lipopeptides exhibiting both narrow and broad spectrum inhibition activities is increasing in the recent past. Therefore, the present study was aimed at isolation and characterization of antimicrobial lipopeptide producing bacterial strains from fecal contaminated soil sample. Results The phenotypic and 16S rRNA gene sequence analysis of all isolates identified them as different species of Gram-negative genera Citrobacter and Enterobacter. They exhibited common phenotypic traits like citrate utilization, oxidase negative and facultative anaerobic growth. The HPLC analysis of solvent extracts obtained from cell free fermented broth revealed the presence of multiple antimicrobial lipopeptides. The comprehensive mass spectral analysis (MALDI-TOF MS and GC-MS) of HPLC purified fractions of different isolates revealed that the lipopeptides varied in their molecular weight between (m/z) 607.21 to 1536.16 Da. Isomers of mass ion m/z 984/985 Da was produced by all strains. The 1495 Da lipopeptides produced by strains S-3 and S-11 were fengycin analogues and most active against all strains. While amino acid analysis of lipopeptides suggested most of them had similar composition as in iturins, fengycins, kurstakins and surfactins, differences in their β-hydroxy fatty acid content proposed them to be isoforms of these lipopeptides. Conclusion Although antimicrobial producing strains can be used as biocontrol agents in food preservation, strains with ability to produce multiple antimicrobial lipopeptides have potential applications in biotechnology sectors such as pharmaceutical and cosmetic industry. This is the first report on antibacterial lipopeptides production by strains of Citrobacter and Enterobacter. PMID

  1. Cationic Net Charge and Counter Ion Type as Antimicrobial Activity Determinant Factors of Short Lipopeptides

    PubMed Central

    Greber, Katarzyna E.; Dawgul, Malgorzata; Kamysz, Wojciech; Sawicki, Wieslaw

    2017-01-01

    To get a better insight into the antimicrobial potency of short cationic lipopeptides, 35 new entities were synthesized using solid phase peptide strategy. All newly obtained lipopeptides were designed to be positively charged from +1 to +4. This was achieved by introducing basic amino acid - lysine - into the lipopeptide structure and had a hydrophobic fatty acid chain attached. Lipopeptides were subjected to microbiological tests using reference strains of Gram-negative bacteria: Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris, Pseudomonas aeruginosa, Gram-positive bacteria: Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis, Enterococcus faecalis, and fungi: Candida albicans, Candida tropicalis, Aspergillus brasiliensis. The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and minimal fungicidal concentration (MFC) were established for each strain. The toxicity toward human cells was determined by hemolysis tests via minimum hemolytic concentration (MHC) determination. The effect of the trifluoroacetic acid (TFA) counter ion on the antimicrobial activity of lipopeptides was also examined by its removing and performing the antimicrobial tests using counter ion-free compounds. The study shows that lipopeptides are more potent against Gram-positive than Gram-negative strains. It was revealed that positive charge equals at least +2 is a necessary condition to observe significant antimicrobial activity, but only when it is balanced with a proper length of hydrophobic fatty acid chain. The hemolytic activity of lipopeptides strongly depends on amino acid composition of the hydrophilic portion of the molecule as well as fatty acid chain length. Compounds endowed with a greater positive charge were more toxic to human erythrocytes. This should be considered during new lipopeptide molecules design. Our studies also revealed the TFA counter ion has no significant effect on the antimicrobial behavior of cationic

  2. Anabaenolysins, Novel Cytolytic Lipopeptides from Benthic Anabaena Cyanobacteria

    PubMed Central

    Jokela, Jouni; Oftedal, Linn; Herfindal, Lars; Permi, Perttu; Wahlsten, Matti; Døskeland, Stein Ove; Sivonen, Kaarina

    2012-01-01

    Two novel cyclic lipopeptides, anabaenolysin A and anabaenolysin B, were isolated from two benthic cyanobacterial strains of the genus Anabaena. This novel class of cyanobacterial lipopeptides has a general structure of a small peptide ring consisting of four amino acids from which two are proteinogenic and two unusual; glycine1, glycine2, 2-(3-amino-5-oxytetrahydrofuran-2-yl)-2-hydroxyacetic acid3 and a long unsaturated C18 β-amino acid4 with a conjugated triene structure. They are distinguished by the presence of a conjugated dienic structure in the C18 β-amino acid present in anabaenolysin A but not in anabaenolysin B. Conjugated triene structure generates a typical UV spectrum for anabaenolysins for easy recognition. Anabaenolysin A constituted up to 400 ppm of the cyanobacterial dry weight. We found evidence of thirteen variants of anabaenolysins in one cyanobacterial strain. This suggests that the anabaenolysins are an important class of secondary metabolites in benthic Anabaena cyanobacteria. Both anabaenolysin A and B had cytolytic activity on a number of mammalian cell lines. PMID:22829929

  3. Effect of glycoamphiphiles on the solubilization and dendritic cell uptake of a lipopeptide: a preliminary study.

    PubMed

    Bonnet, Dominique; Angyalosi, Gerhild; Demory, Alexandra; Santraine, Valérie; Boulet, Arnaud; Spriet, Corentin; Héliot, Laurent; Gras-Masse, Hélène; Grandjean, Cyrille

    2005-01-01

    The selective delivery of antigens to professional antigen-presenting cells represents a promising approach to improve vaccine efficacy. Addition of a glycoamphiphile to a lipopeptide, whose interest for vaccination is now well-established, greatly favors its solubilization in aqueous solutions through the formation of mixed vesicles. Flow cytometry experiments indicate that this formulation does not diminish the uptake of the lipopeptide by the dendritic cells (DCs). These preliminary results suggest a possible straightforward, noncovalent targeting of cocktail-lipopeptide vaccines to the DCs via carbohydrate receptor-mediated endocytosis.

  4. Locally applied macrophage-activating lipopeptide-2 (MALP-2) promotes early vascularization of implanted porous polyethylene (Medpor®).

    PubMed

    Laschke, M W; Augustin, V; Kleer, S; Tschernig, T; Menger, M D

    2014-11-01

    Porous polyethylene (Medpor®) is frequently used in craniofacial reconstructive surgery. Rapid vascularization of the biomaterial crucially contributes to its adequate incorporation without complications. Macrophage-activating lipopeptide-2 (MALP-2) is a toll-like receptor (TLR)-2/6 agonist with pro-angiogenic properties. Herein we analyzed whether local single-shot application of MALP-2 improves the angiogenic host tissue response to Medpor®. Medpor® (3 mm×3 mm×0.25 mm) was implanted into dorsal skinfold chambers of BALB/c mice topically exposed to different MALP-2 doses (0.1 and 0.5 μg) or vehicle (control). The vascularization of the implants and the inflammatory foreign body reaction was analyzed using intravital fluorescence microscopy, histology and immunohistochemistry over 14 days. MALP-2 treatment dose-dependently improved the vascularization of Medpor®, as indicated by a significantly higher functional microvessel density at the border and center of the implants when compared to controls. This was associated with a temporary increase of adherent leukocytes in host tissue venules during the first 3 days after implantation. At day 14, implants in MALP-2-treated chambers were surrounded by granulation tissue, which exhibited a significantly higher density of CD31-positive microvessels and number of F4/80-positive macrophages when compared to controls. Additional biomaterial-free chambers did not show any signs of angiogenesis when treated with MALP-2. This indicates that locally applied MALP-2 effectively stimulates the early vascularization of Medpor® without inducing any local or systemic side effects. Accordingly, this easy approach may further improve the rapid incorporation of this biomaterial at the implantation site.

  5. Innovative chemical synthesis and conformational hints on the lipopeptide liraglutide.

    PubMed

    Guryanov, Ivan; Bondesan, Alex; Visentini, Dario; Orlandin, Andrea; Biondi, Barbara; Toniolo, Claudio; Formaggio, Fernando; Ricci, Antonio; Zanon, Jacopo; Cabri, Walter

    2016-07-01

    Liraglutide is a new generation lipopeptide drug used for the treatment of type II diabetes. In this work, we describe new approaches for its preparation fully by chemical methods. The key step of these strategies is the synthesis in solution of the Lys/γ-Glu building block, Fmoc-Lys-(Pal-γ-Glu-OtBu)-OH, in which Lys and Glu residues are linked through their side chains and γ-Glu is N(α) -palmitoylated. This dipeptide derivative is then inserted into the peptide sequence on solid phase. As liraglutide is obtained with great purity and high yield, our approach can be particularly attractive for an industrial production. We also report here the results of a circular dichroism conformational analysis in a membrane mimetic environment that offers new insights into the mechanism of action of liraglutide. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

  6. Drug Delivery via Cell Membrane Fusion Using Lipopeptide Modified Liposomes

    PubMed Central

    2016-01-01

    Efficient delivery of drugs to living cells is still a major challenge. Currently, most methods rely on the endocytotic pathway resulting in low delivery efficiency due to limited endosomal escape and/or degradation in lysosomes. Here, we report a new method for direct drug delivery into the cytosol of live cells in vitro and invivo utilizing targeted membrane fusion between liposomes and live cells. A pair of complementary coiled-coil lipopeptides was embedded in the lipid bilayer of liposomes and cell membranes respectively, resulting in targeted membrane fusion with concomitant release of liposome encapsulated cargo including fluorescent dyes and the cytotoxic drug doxorubicin. Using a wide spectrum of endocytosis inhibitors and endosome trackers, we demonstrate that the major site of cargo release is at the plasma membrane. This method thus allows for the quick and efficient delivery of drugs and is expected to have many invitro, ex vivo, and invivo applications. PMID:27725960

  7. Induced Seismicity Monitoring System

    NASA Astrophysics Data System (ADS)

    Taylor, S. R.; Jarpe, S.; Harben, P.

    2014-12-01

    There are many seismological aspects associated with monitoring of permanent storage of carbon dioxide (CO2) in geologic formations. Many of these include monitoring underground gas migration through detailed tomographic studies of rock properties, integrity of the cap rock and micro seismicity with time. These types of studies require expensive deployments of surface and borehole sensors in the vicinity of the CO2 injection wells. Another problem that may exist in CO2 sequestration fields is the potential for damaging induced seismicity associated with fluid injection into the geologic reservoir. Seismic hazard monitoring in CO2 sequestration fields requires a seismic network over a spatially larger region possibly having stations in remote settings. Expensive observatory-grade seismic systems are not necessary for seismic hazard deployments or small-scale tomographic studies. Hazard monitoring requires accurate location of induced seismicity to magnitude levels only slightly less than that which can be felt at the surface (e.g. magnitude 1), and the frequencies of interest for tomographic analysis are ~1 Hz and greater. We have developed a seismo/acoustic smart sensor system that can achieve the goals necessary for induced seismicity monitoring in CO2 sequestration fields. The unit is inexpensive, lightweight, easy to deploy, can operate remotely under harsh conditions and features 9 channels of recording (currently 3C 4.5 Hz geophone, MEMS accelerometer and microphone). An on-board processor allows for satellite transmission of parameter data to a processing center. Continuous or event-detected data is kept on two removable flash SD cards of up to 64+ Gbytes each. If available, data can be transmitted via cell phone modem or picked up via site visits. Low-power consumption allows for autonomous operation using only a 10 watt solar panel and a gel-cell battery. The system has been successfully tested for long-term (> 6 months) remote operations over a wide range

  8. Structural Analysis of the Lipopeptide Produced by the Bacillus subtilis Mutant R2-104 with Mutagenesis.

    PubMed

    Meng, Yong; Zhao, Wei; You, Jia; Gang, Hong-Ze; Liu, Jin-Feng; Yang, Shi-Zhong; Ye, Ru-Qiang; Mu, Bo-Zhong

    2016-07-01

    The lipopeptide and its homologues are a kind of the five major biosurfactants with prominent interfacial and biological activities. A suite of mutagenesis method was adopted to expose a wild lipopeptide-producing strain Bacillus subtilis HSO121 to improve lipopeptide yield, and a stable mutant named R2-104 with a 2.0-fold production of lipopeptide was obtained. Compared to that of the wild strain HSO121, the lipopeptide produced by R2-104 showed a similar surface activity, but the course profiles of lipopeptide production during cultivation were different, with the peak yield of 500 mg at about 9 h by R2-104, and 400 mg at about 5 h by HSO121. The constituent abundance of the lipopeptide homologues produced by R2-104 was also different from that by HSO121. Combined methods of ESI-MS, GC-MS and MS-MS were applied for structural characterization of lipopeptide homologues, and it showed that the lipopeptides produced by R2-104 and HSO121 were attributed to a surfactin family with different constituents. The dominant constituent of the surfactin family produced by R2-104 was anteiso C15-surfactin with a relative content of 43.8 %, while the dominant one produced by HSO121was iso C14-surfactin with a relative content of 33.1 %.

  9. Cyclic Lipopeptides from Bacillus subtilis ABS–S14 Elicit Defense-Related Gene Expression in Citrus Fruit

    PubMed Central

    Waewthongrak, Waewruedee; Leelasuphakul, Wichitra; McCollum, Greg

    2014-01-01

    Effects of cyclic lipopeptides (CLPs) obtained from Bacillus subtilis ABS-S14 on eliciting defense-related gene transcription and activity of defense-related enzymes; glucanase (GLU), chitinase (CHI), peroxidase (POX) and lipoxygenase (LOX) in Citrus sinensis cv. Valencia fruit were determined. The maximum level of GLU transcripts induced in fruit treated with fengycin was significantly greatest among treatments at 48 h. Surfactin enhanced the LOX and POX transcripts. In parallel, corresponding enzyme activities were correlated with changes in gene expression observed in fruit inoculated with Penicillium digitatum following treatment with individual CLPs. Synergistic effects of fengycin and iturin A, fengycin and surfactin were shown in gene transcript of GLU and CHI, respectively, and surfactin induced POX and LOX gene expression of citrus flavedo without pathogen infection. These results suggest that fengycin and surfactin act as elicitors of defense-related gene expression in “Valencia” fruit following infection. PMID:25329301

  10. Cyclic LIPopeptides from Bacillus subtilis ABS-S14 elicit defense-related gene expression in citrus fruit.

    PubMed

    Waewthongrak, Waewruedee; Leelasuphakul, Wichitra; McCollum, Greg

    2014-01-01

    Effects of cyclic lipopeptides (CLPs) obtained from Bacillus subtilis ABS-S14 on eliciting defense-related gene transcription and activity of defense-related enzymes; glucanase (GLU), chitinase (CHI), peroxidase (POX) and lipoxygenase (LOX) in Citrus sinensis cv. Valencia fruit were determined. The maximum level of GLU transcripts induced in fruit treated with fengycin was significantly greatest among treatments at 48 h. Surfactin enhanced the LOX and POX transcripts. In parallel, corresponding enzyme activities were correlated with changes in gene expression observed in fruit inoculated with Penicillium digitatum following treatment with individual CLPs. Synergistic effects of fengycin and iturin A, fengycin and surfactin were shown in gene transcript of GLU and CHI, respectively, and surfactin induced POX and LOX gene expression of citrus flavedo without pathogen infection. These results suggest that fengycin and surfactin act as elicitors of defense-related gene expression in "Valencia" fruit following infection.

  11. Pyrexia, anorexia, adipsia, and depressed motor activity in rats during systemic inflammation induced by the Toll-like receptors-2 and -6 agonists MALP-2 and FSL-1.

    PubMed

    Hübschle, Thomas; Mütze, Jörg; Mühlradt, Peter F; Korte, Stefan; Gerstberger, Rüdiger; Roth, Joachim

    2006-01-01

    Macrophage-activating lipopeptide-2 (MALP-2) from Mycoplasma fermentans has been identified as a pathogen-associated molecular pattern of Mycoplasmas that causes activation of the innate immune system through the activation of the heterodimeric Toll-like receptors (TLRs)-2 and -6. The aim of this study was to characterize the ability of MALP-2 and a synthetic analog fibroblast-stimulating lipopeptide-1 (FSL-1; represents the NH2-terminal sequence of a lipoprotein from M. salivarium) to act as exogenous pyrogens, to induce formation of cytokines (endogenous pyrogens), and to cause sickness behavior, such as depressed motor activity, anorexia, and adipsia. For this purpose, body temperature, activity, food intake, and water intake were recorded for 3 days by use of telemetry devices in several groups of rats treated with MALP-2/FSL-1 or the respective control solutions. Intraperitoneal injections of FSL-1 caused fever at doses of 10 or 100 microg/kg, which was preceded by a pronounced phase of hypothermia in response to a dose of 1,000 microg/kg. The maximal fever (a peak of 1.5 degrees C above baseline) was caused by the 100 microg/kg dose with almost identical responses to both MALP-2 and FSL-1. Fever was accompanied by pronounced rises of the proinflammatory cytokines TNF and IL-6 in plasma. Treatment with the TLR-2 and -6 agonists further induced a dose-dependent manifestation of anorexia and adipsia, as well as a reduction of motor activity. We could thus demonstrate that activation of TLR-2 and -6 can induce systemic inflammation in rats accompanied by the classical signs of brain-controlled illness responses.

  12. Solubilization and stabilization of isolated photosystem I complex with lipopeptide detergents.

    PubMed

    Wang, Xiaoqiang; Huang, Guihong; Yu, Daoyong; Ge, Baosheng; Wang, Jiqian; Xu, Fengxi; Huang, Fang; Xu, Hai; Lu, Jian R

    2013-01-01

    It is difficult to maintain a target membrane protein in a soluble and functional form in aqueous solution without biological membranes. Use of surfactants can improve solubility, but it remains challenging to identify adequate surfactants that can improve solubility without damaging their native structures and biological functions. Here we report the use of a new class of lipopeptides to solubilize photosystem I (PS-I), a well known membrane protein complex. Changes in the molecular structure of these surfactants affected their amphiphilicity and the goal of this work was to exploit a delicate balance between detergency and biomimetic performance in PS-I solubilization via their binding capacity. Meanwhile, the effects of these surfactants on the thermal and structural stability and functionality of PS-I in aqueous solution were investigated by circular dichroism, fluorescence spectroscopy, SDS-PAGE analysis and O2 uptake measurements, respectively. Our studies showed that the solubility of PS-I depended on both the polarity and charge in the hydrophilic head of the lipopeptides and the length of its hydrophobic tail. The best performing lipopeptides in favour of PS-I solubility turned out to be C14DK and C16DK, which were comparable to the optimal amphiphilicity of the conventional chemical surfactants tested. Lipopeptides showed obvious advantages in enhancing PS-I thermostability over sugar surfactant DDM and some full peptide amphiphiles reported previously. Fluorescence spectroscopy along with SDS-PAGE analysis demonstrated that lipopeptides did not undermine the polypeptide composition and conformation of PS-I after solubilization; instead they showed better performance in improving the structural stability and integrity of this multi-subunit membrane protein than conventional detergents. Furthermore, O2 uptake measurements indicated that PS-I solubilized with lipopeptides maintained its functionality. The underlying mechanism for the favorable actions of

  13. An NLRP7-containing inflammasome mediates recognition of microbial lipopeptides in human macrophages.

    PubMed

    Khare, Sonal; Dorfleutner, Andrea; Bryan, Nicole B; Yun, Chawon; Radian, Alexander D; de Almeida, Lucia; Rojanasakul, Yon; Stehlik, Christian

    2012-03-23

    Cytosolic pathogen- and damage-associated molecular patterns are sensed by pattern recognition receptors, including members of the nucleotide-binding domain and leucine-rich repeat-containing gene family (NLR), which cause inflammasome assembly and caspase-1 activation to promote maturation and release of the inflammatory cytokines interleukin-1β (IL-1β) and IL-18 and induction of pyroptosis. However, the contribution of most of the NLRs to innate immunity, host defense, and inflammasome activation and their specific agonists are still unknown. Here we describe identification and characterization of an NLRP7 inflammasome in human macrophages, which is induced in response to microbial acylated lipopeptides. Activation of NLRP7 promoted ASC-dependent caspase-1 activation, IL-1β and IL-18 maturation, and restriction of intracellular bacterial replication, but not caspase-1-independent secretion of the proinflammatory cytokines IL-6 and tumor necrosis factor-α. Our study therefore increases our currently limited understanding of NLR activation, inflammasome assembly, and maturation of IL-1β and IL-18 in human macrophages.

  14. Inhibition of fungal and bacterial plant pathogens in vitro and in planta with ultrashort cationic lipopeptides.

    PubMed

    Makovitzki, Arik; Viterbo, Ada; Brotman, Yariv; Chet, Ilan; Shai, Yechiel

    2007-10-01

    Plant diseases constitute an emerging threat to global food security. Many of the currently available antimicrobial agents for agriculture are highly toxic and nonbiodegradable and cause extended environmental pollution. Moreover, an increasing number of phytopathogens develop resistance to them. Recently, we have reported on a new family of ultrashort antimicrobial lipopeptides which are composed of only four amino acids linked to fatty acids (A. Makovitzki, D. Avrahami, and Y. Shai, Proc. Natl. Acad. Sci. USA 103:15997-16002, 2006). Here, we investigated the activities in vitro and in planta and the modes of action of these short lipopeptides against plant-pathogenic bacteria and fungi. They act rapidly, at low micromolar concentrations, on the membranes of the microorganisms via a lytic mechanism. In vitro microscopic analysis revealed wide-scale damage to the microorganism's membrane, in addition to inhibition of pathogen growth. In planta potent antifungal activity was demonstrated on cucumber fruits and leaves infected with the pathogen Botrytis cinerea as well as on corn leaves infected with Cochliobolus heterostrophus. Similarly, treatment with the lipopeptides of Arabidopsis leaves infected with the bacterial leaf pathogen Pseudomonas syringae efficiently and rapidly reduced the number of bacteria. Importantly, in contrast to what occurred with many native lipopeptides, no toxicity was observed on the plant tissues. These data suggest that the ultrashort lipopeptides could serve as native-like antimicrobial agents economically feasible for use in plant protection.

  15. The interaction mechanism between lipopeptide (daptomycin) and polyamidoamine (PAMAM) dendrimers.

    PubMed

    Chanvorachote, Boontarika; Qiu, Jiang; Muangsiri, Walaisiri; Nimmannit, Ubonthip; Kirsch, Lee E

    2015-04-01

    The interaction mechanism of lipopeptide antibiotic daptomycin and polyamidoamine (PAMAM) dendrimers was studied using fluorescence spectroscopy. The fluorescence changes observed are associated with daptomycin-dendrimer interactions. The binding isotherms were constructed by plotting the fluorescence difference at 460 nm from kynurenine (Kyn-13) of daptomycin in the presence and absence of dendrimer. A one-site and two-site binding model were quantitatively generated to estimate binding capacity and affinity constants from the isotherms. The shape of the binding isotherm and the dependence of the estimated capacity constants on dendrimer sizes and solvent pH values provide meaningful insight into the mechanism of interactions. A one-site binding model adequately describes the binding isotherm obtained under a variety of experimental conditions with dendrimers of various sizes in the optimal binding pH region 3.5 to 4.5. Comparing the pH-dependent binding capacity with the ionization profiles of daptomycin and dendrimer, the ionized aspartic acid residue (Asp-9) of daptomycin primarily interact with PAMAM cationic surface amine.

  16. Hydrocarbon-stapled lipopeptides exhibit selective antimicrobial activity.

    PubMed

    Jenner, Zachary B; Crittenden, Christopher M; Gonzalez, Martín; Brodbelt, Jennifer S; Bruns, Kerry A

    2017-01-10

    Antimicrobial peptides (AMPs) occur widely in nature and have been studied for their therapeutic potential. AMPs are of interest due to the large number of possible chemical structural combinations using natural and unnatural amino acids, with varying effects on their biological activities. Using physicochemical properties from known naturally occurring amphipathic cationic AMPs, several hydrocarbon-stapled lipopeptides (HSLPs) were designed, synthesized, and tested for antimicrobial properties. Peptides were chemically modified by N-terminal acylation, C-terminal amidation, and some were hydrocarbon stapled by intramolecular olefin metathesis. The effects of peptide length, amphipathic character, and stapling on antimicrobial activity were tested against Escherichia coli, three species of Gram-positive bacteria (Staphylococcus aureus, Bacillus megaterium, and Enterococcus faecalis), and two strains of Candida albicans. Peptides were shown to disrupt liposomes of different phospholipid composition, as measured by leakage of a fluorescent compound from vesicles. Peptides with (S)-2-(4'-pentenyl)-alanine substituted for L-alanine in a reference peptide showed a marked increase in antimicrobial activity, hemolysis, and membrane disruption. Stapled peptides exhibited slightly higher antimicrobial potency; those with greatest hydrophobic character showed the greatest hemolysis and liposome leakage, but lower antimicrobial activity. The results support a model of HSLPs as membrane-disruptive AMPs with potent antimicrobial activity and relatively low hemolytic potential at biologically active peptide concentrations. This article is protected by copyright. All rights reserved.

  17. Lipopeptide nanoparticles for potent and selective siRNA delivery in rodents and nonhuman primates.

    PubMed

    Dong, Yizhou; Love, Kevin T; Dorkin, J Robert; Sirirungruang, Sasilada; Zhang, Yunlong; Chen, Delai; Bogorad, Roman L; Yin, Hao; Chen, Yi; Vegas, Arturo J; Alabi, Christopher A; Sahay, Gaurav; Olejnik, Karsten T; Wang, Weiheng; Schroeder, Avi; Lytton-Jean, Abigail K R; Siegwart, Daniel J; Akinc, Akin; Barnes, Carmen; Barros, Scott A; Carioto, Mary; Fitzgerald, Kevin; Hettinger, Julia; Kumar, Varun; Novobrantseva, Tatiana I; Qin, June; Querbes, William; Koteliansky, Victor; Langer, Robert; Anderson, Daniel G

    2014-03-18

    siRNA therapeutics have promise for the treatment of a wide range of genetic disorders. Motivated by lipoproteins, we report lipopeptide nanoparticles as potent and selective siRNA carriers with a wide therapeutic index. Lead material cKK-E12 showed potent silencing effects in mice (ED50 ∼ 0.002 mg/kg), rats (ED50 < 0.01 mg/kg), and nonhuman primates (over 95% silencing at 0.3 mg/kg). Apolipoprotein E plays a significant role in the potency of cKK-E12 both in vitro and in vivo. cKK-E12 was highly selective toward liver parenchymal cell in vivo, with orders of magnitude lower doses needed to silence in hepatocytes compared with endothelial cells and immune cells in different organs. Toxicity studies showed that cKK-E12 was well tolerated in rats at a dose of 1 mg/kg (over 100-fold higher than the ED50). To our knowledge, this is the most efficacious and selective nonviral siRNA delivery system for gene silencing in hepatocytes reported to date.

  18. Macrophage-activating lipopeptide-2 exerts protective effects in a murine sepsis model.

    PubMed

    Zeckey, Christian; Tschernig, Thomas; Hildebrand, Frank; Frink, Michael; Frömke, Cornelia; Dorsch, Martina; Krettek, Christian; Barkhausen, Tanja

    2010-06-01

    It is still a major problem to achieve successful therapy in polymicrobial sepsis. Stimulation of the innate immune system via Toll-like receptors (TLRs) 2 and 6 had beneficial effects on chronic inflammatory disorders and a severe peritonitis model when administered 4 days before induction. In the present study, the hypothesis whether the TLR-2 and TLR-6 pathway can also be used as a therapeutic agent parallel to sepsis induction and several hours after the induction was tested. Therefore, the TLR-2 and TLR-6 agonist macrophage-activating lipopeptide 2 (MALP-2) was applied simultaneous to cecal ligation and puncture-sepsis induction and 6 h thereafter. Vehicle-treated animals served as controls. Survival, activity, cytokine levels at different time points, and pulmonary neutrophil infiltration were determined. Improved survival was found after both MALP-2 treatments in comparison with untreated controls. The treatment resulted in reduced monocyte chemotactic protein 1 levels in the plasma; furthermore, pulmonary infiltration by neutrophils was decreased. These results demonstrate a beneficial effect of MALP-2 as a therapeutic agent in polymicrobial sepsis in the cecal ligation and puncture mouse model.

  19. Additive and synergistic membrane permeabilization by antimicrobial (lipo)peptides and detergents.

    PubMed

    Patel, Hiren; Huynh, Quang; Bärlehner, Dominik; Heerklotz, Heiko

    2014-05-20

    Certain antibiotic peptides are thought to permeabilize membranes of pathogens by effects that are also observed for simple detergents, such as membrane thinning and disordering, asymmetric bilayer expansion, toroidal pore formation, and micellization. Here we test the hypothesis that such peptides act additively with detergents when applied in parallel. Additivity is defined analogously to a fractional inhibitory concentration index of unity, and the extent and mechanism of leakage is measured by the fluorescence lifetime-based vesicle leakage assay using calcein-loaded vesicles. Good additivity was found for the concerted action of magainin 2, the fungicidal lipopeptide class of surfactins from Bacillus subtilis QST713, and the detergent octyl glucoside, respectively, with the detergent C12EO8. Synergistic or superadditive action was observed for fengycins from B. subtilis, as well as the detergent CHAPS, when combined with C12EO8. The results illustrate two mechanisms of synergistic action: First, maximal leakage requires an optimum degree of heterogeneity in the system that may be achieved by mixing a graded with an all-or-none permeabilizer. (The optimal perturbation should be focused to certain defect structures, yet not to the extent that some vesicles are not affected at all.) Second, a cosurfactant may enhance the bioavailability of a poorly soluble peptide. The results are important for understanding the concerted action of membrane-permeabilizing compounds in biology as well as for optimizing formulations of such antimicrobials for medical applications or crop protection.

  20. Prevention and mitigation of acute radiation syndrome in mice by synthetic lipopeptide agonists of Toll-like receptor 2 (TLR2).

    PubMed

    Shakhov, Alexander N; Singh, Vijay K; Bone, Frederick; Cheney, Alec; Kononov, Yevgeniy; Krasnov, Peter; Bratanova-Toshkova, Troitza K; Shakhova, Vera V; Young, Jason; Weil, Michael M; Panoskaltsis-Mortari, Angela; Orschell, Christie M; Baker, Patricia S; Gudkov, Andrei; Feinstein, Elena

    2012-01-01

    Bacterial lipoproteins (BLP) induce innate immune responses in mammals by activating heterodimeric receptor complexes containing Toll-like receptor 2 (TLR2). TLR2 signaling results in nuclear factor-kappaB (NF-κB)-dependent upregulation of anti-apoptotic factors, anti-oxidants and cytokines, all of which have been implicated in radiation protection. Here we demonstrate that synthetic lipopeptides (sLP) that mimic the structure of naturally occurring mycoplasmal BLP significantly increase mouse survival following lethal total body irradiation (TBI) when administered between 48 hours before and 24 hours after irradiation. The TBI dose ranges against which sLP are effective indicate that sLP primarily impact the hematopoietic (HP) component of acute radiation syndrome. Indeed, sLP treatment accelerated recovery of bone marrow (BM) and spleen cellularity and ameliorated thrombocytopenia of irradiated mice. sLP did not improve survival of irradiated TLR2-knockout mice, confirming that sLP-mediated radioprotection requires TLR2. However, sLP was radioprotective in chimeric mice containing TLR2-null BM on a wild type background, indicating that radioprotection of the HP system by sLP is, at least in part, indirect and initiated in non-BM cells. sLP injection resulted in strong transient induction of multiple cytokines with known roles in hematopoiesis, including granulocyte colony-stimulating factor (G-CSF), keratinocyte chemoattractant (KC) and interleukin-6 (IL-6). sLP-induced cytokines, particularly G-CSF, are likely mediators of the radioprotective/mitigative activity of sLP. This study illustrates the strong potential of LP-based TLR2 agonists for anti-radiation prophylaxis and therapy in defense and medical scenarios.

  1. Prevention and Mitigation of Acute Radiation Syndrome in Mice by Synthetic Lipopeptide Agonists of Toll-Like Receptor 2 (TLR2)

    PubMed Central

    Shakhov, Alexander N.; Singh, Vijay K.; Bone, Frederick; Cheney, Alec; Kononov, Yevgeniy; Krasnov, Peter; Bratanova-Toshkova, Troitza K.; Shakhova, Vera V.; Young, Jason; Weil, Michael M.; Panoskaltsis-Mortari, Angela; Orschell, Christie M.; Baker, Patricia S.; Gudkov, Andrei; Feinstein, Elena

    2012-01-01

    Bacterial lipoproteins (BLP) induce innate immune responses in mammals by activating heterodimeric receptor complexes containing Toll-like receptor 2 (TLR2). TLR2 signaling results in nuclear factor-kappaB (NF-κB)-dependent upregulation of anti-apoptotic factors, anti-oxidants and cytokines, all of which have been implicated in radiation protection. Here we demonstrate that synthetic lipopeptides (sLP) that mimic the structure of naturally occurring mycoplasmal BLP significantly increase mouse survival following lethal total body irradiation (TBI) when administered between 48 hours before and 24 hours after irradiation. The TBI dose ranges against which sLP are effective indicate that sLP primarily impact the hematopoietic (HP) component of acute radiation syndrome. Indeed, sLP treatment accelerated recovery of bone marrow (BM) and spleen cellularity and ameliorated thrombocytopenia of irradiated mice. sLP did not improve survival of irradiated TLR2-knockout mice, confirming that sLP-mediated radioprotection requires TLR2. However, sLP was radioprotective in chimeric mice containing TLR2-null BM on a wild type background, indicating that radioprotection of the HP system by sLP is, at least in part, indirect and initiated in non-BM cells. sLP injection resulted in strong transient induction of multiple cytokines with known roles in hematopoiesis, including granulocyte colony-stimulating factor (G-CSF), keratinocyte chemoattractant (KC) and interleukin-6 (IL-6). sLP-induced cytokines, particularly G-CSF, are likely mediators of the radioprotective/mitigative activity of sLP. This study illustrates the strong potential of LP-based TLR2 agonists for anti-radiation prophylaxis and therapy in defense and medical scenarios. PMID:22479357

  2. Teaching 'old' polymyxins new tricks: new-generation lipopeptides targeting gram-negative 'superbugs'.

    PubMed

    Velkov, Tony; Roberts, Kade D; Nation, Roger L; Wang, Jiping; Thompson, Philip E; Li, Jian

    2014-05-16

    The antimicrobial lipopeptides polymyxin B and E (colistin) are being used as a 'last-line' therapy for infections caused by multidrug-resistant Gram-negative pathogens. Polymyxin resistance implies a total lack of antibiotics for the treatment of life-threatening infections caused by the Gram-negative 'superbugs'. This report details the structure-activity relationships (SAR) based design, in toto synthesis, and preclinical evaluation of a series of novel polymyxin lipopeptides with better antibacterial activity against polymyxin-resistant Gram-negative bacteria.

  3. Identification of lipopeptides produced by Bacillus subtilis Czk1 isolated from the aerial roots of rubber trees.

    PubMed

    He, C P; Fan, L Y; Wu, W H; Liang, Y Q; Li, R; Tang, W; Zheng, X L; Xiao, Y N; Liu, Z X; Zheng, F C

    2017-02-23

    We obtained a strain of Bacillus subtilis, which we named Czk1, from the aerial roots of rubber trees. This bacterial isolate exhibits strong antagonistic activity against Ganoderma pseudoferreum, Phellinus noxius, Helicobasidium compactum, Rigidoporus lignosus, Sphaerostilbe repens, and Colletotrichum gloeosporioides. Our earlier research has shown that the antagonistic activity of a fermentation supernatant Czk1 isolate produces a complex mixture of lipopeptides. In this study, we used methanol to extract crude lipopeptides, purified them using a Sephadex G-25 column, cloned the lipopeptide genes, and analyzed purified fractions by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS) to identify the lipopeptides from B. subtilis strain Czk1. The cloned lipopeptide genes included those that encode the enzymes lpa, ituD, sfp, and fenB. The crude lipopeptides were purified and found in five fractions. Further analysis revealed that five fractions of the purified composition contained members of the surfactin, iturin, fengycin, and bacillomycin families of antibiotics. This suggests that these lipopeptides from strain Czk1 have potential as plant disease biocontrol agents.

  4. Biophysical characterization of V3-lipopeptide liposomes influencing HIV-1 infectivity

    SciTech Connect

    Rizos, Apostolos K. . E-mail: Rizos@iesl.forth.gr; Baritaki, Stavroula; Tsikalas, Ioannis; Doetschman, David C.; Spandidos, Demetrios A.; Krambovitis, Elias; E-mail: krambo@imbb.forth.gr

    2007-04-20

    The V3-loop of the HIV-1 gp120 alters host cell immune function and modulates infectivity. We investigated biophysical parameters of liposome constructs with embedded lipopeptides from the principle neutralizing domain of the V3-loop and their influence on viral infectivity. Dynamic light scattering measurements showed liposome supramolecular structures with hydrodynamic radius of the order of 900 and 1300 nm for plain and V3-lipopeptide liposomes. Electron paramagnetic resonance measurements showed almost identical local microenvironment. The difference in liposome hydrodynamic radius was attributed to the fluctuating ionic environment of the V3-lipopeptide liposomes. In vitro HIV-1 infectivity assays showed that plain liposomes reduced virus production in all cell cultures, probably due to the hydrophobic nature of the aggregates. Liposomes carrying V3-lipopeptides with different cationic potentials restored and even enhanced infectivity (p < 0.05). These results highlight the need for elucidation of the involvement of lipid bilayers as dynamic components in supramolecular structures and in HIV-1 fusion mechanisms.

  5. Recognition of lipopeptide patterns by Toll-like receptor 2-Toll-like receptor 6 heterodimer.

    PubMed

    Kang, Jin Young; Nan, Xuehua; Jin, Mi Sun; Youn, Suk-Jun; Ryu, Young Hee; Mah, Shinjee; Han, Seung Hyun; Lee, Hayyoung; Paik, Sang-Gi; Lee, Jie-Oh

    2009-12-18

    Toll-like receptor 2 (TLR2) initiates potent immune responses by recognizing diacylated and triacylated lipopeptides. Its ligand specificity is controlled by whether it heterodimerizes with TLR1 or TLR6. We have determined the crystal structures of TLR2-TLR6-diacylated lipopeptide, TLR2-lipoteichoic acid, and TLR2-PE-DTPA complexes. PE-DTPA, 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine-N-diethylenetriaminepentaacetic acid, is a synthetic phospholipid derivative. Two major factors contribute to the ligand specificity of TLR2-TLR1 or TLR2-TLR6 heterodimers. First, the lipid channel of TLR6 is blocked by two phenylalanines. Simultaneous mutation of these phenylalanines made TLR2-TLR6 fully responsive not only to diacylated but also to triacylated lipopeptides. Second, the hydrophobic dimerization interface of TLR2-TLR6 is increased by 80%, which compensates for the lack of amide lipid interaction between the lipopeptide and TLR2-TLR6. The structures of the TLR2-lipoteichoic acid and the TLR2-PE-DTPA complexes demonstrate that a precise interaction pattern of the head group is essential for a robust immune response by TLR2 heterodimers.

  6. Cyclic lipopeptide profile of three Bacillus subtilus strains; antagonists of Fusarium head blight

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The cyclic lipopeptide profile of three Bacillus subtilis strains (AS 43.3, AS 43.4, and OH 131.1) was determined using mass spectroscopy. The strains are antagonists of Gibberella zeae and have been shown to be effective in reducing Fusarium head blight in wheat. Strains AS 43.3 and AS 43.4 produ...

  7. Second stage production of iturin A by induced germination of Bacillus subtilis RB14.

    PubMed

    Rahman, Mohammad Shahedur; Ano, Takashi; Shoda, Makoto

    2006-10-01

    Bacillus subtilis RB14, a dual producer of lipopeptide antibiotics iturin A and surfactin undergoes sporulation in the submerged fermentation and the production of these secondary metabolites becomes halted. In this study, production of lipopeptide antibiotics was investigated by induced germination of the spores by heat-activation and nutrient supplementation. The induced spores became metabolically active vegetative state and produced lipopeptide antibiotic iturin A that added up the total production at the end of the fermentation. However, additional production of surfactin was not observed. This second time iturin A production by the germinated cells from the spores was defined as second stage production.

  8. Antimicrobial and Insecticidal: Cyclic Lipopeptides and Hydrogen Cyanide Produced by Plant-Beneficial Pseudomonas Strains CHA0, CMR12a, and PCL1391 Contribute to Insect Killing.

    PubMed

    Flury, Pascale; Vesga, Pilar; Péchy-Tarr, Maria; Aellen, Nora; Dennert, Francesca; Hofer, Nicolas; Kupferschmied, Karent P; Kupferschmied, Peter; Metla, Zane; Ma, Zongwang; Siegfried, Sandra; de Weert, Sandra; Bloemberg, Guido; Höfte, Monica; Keel, Christoph J; Maurhofer, Monika

    2017-01-01

    Particular groups of plant-beneficial fluorescent pseudomonads are not only root colonizers that provide plant disease suppression, but in addition are able to infect and kill insect larvae. The mechanisms by which the bacteria manage to infest this alternative host, to overcome its immune system, and to ultimately kill the insect are still largely unknown. However, the investigation of the few virulence factors discovered so far, points to a highly multifactorial nature of insecticidal activity. Antimicrobial compounds produced by fluorescent pseudomonads are effective weapons against a vast diversity of organisms such as fungi, oomycetes, nematodes, and protozoa. Here, we investigated whether these compounds also contribute to insecticidal activity. We tested mutants of the highly insecticidal strains Pseudomonas protegens CHA0, Pseudomonas chlororaphis PCL1391, and Pseudomonas sp. CMR12a, defective for individual or multiple antimicrobial compounds, for injectable and oral activity against lepidopteran insect larvae. Moreover, we studied expression of biosynthesis genes for these antimicrobial compounds for the first time in insects. Our survey revealed that hydrogen cyanide and different types of cyclic lipopeptides contribute to insecticidal activity. Hydrogen cyanide was essential to full virulence of CHA0 and PCL1391 directly injected into the hemolymph. The cyclic lipopeptide orfamide produced by CHA0 and CMR12a was mainly important in oral infections. Mutants of CMR12a and PCL1391 impaired in the production of the cyclic lipopeptides sessilin and clp1391, respectively, showed reduced virulence in injection and feeding experiments. Although virulence of mutants lacking one or several of the other antimicrobial compounds, i.e., 2,4-diacetylphloroglucinol, phenazines, pyrrolnitrin, or pyoluteorin, was not reduced, these metabolites might still play a role in an insect background since all investigated biosynthetic genes for antimicrobial compounds of strain

  9. [Construction and evaluation of an engineered bacterial strain for producing lipopeptide under anoxic conditions].

    PubMed

    Liang, Xiao-long; Zhao, Feng; Shi, Rong-jiu; Ban, Yun-he; Zhou, Ji-dong; Han, Si-qin; Zhang, Ying

    2015-08-01

    Biosurfactant-facilitated oil recovery is one of the most important aspects of microbial enhanced oil recovery (MEOR). However, the biosurfactant production by biosurfactant-producing microorganisms, most of which are aerobes, is severely suppressed due to the in-situ anoxic conditions within oil reservoirs. In this research, we successfully engineered a strain JD-3, which could grow rapidly and produce lipopeptide under anoxic conditions, by protoplast confusion using a Bacillus amyloliquefaciens strain BQ-2 which produces biosurfactant aerobically, and a facultative anaerobic Pseudomonas stutzeri strain DQ-1 as parent strains. The alignment of 16S rDNA sequence (99% similarity) and comparisons of cell colony morphology showed that fusant JD-3 was closer to the parental strain B. amyloliquefaciens BQ-2. The surface tension of culture broth of fusant JD-3, after 36-hour cultivation under anaerobic conditions, decreased from initially 63.0 to 32.5 mN · m(-1). The results of thin layer chromatography and infrared spectrum analysis demonstrated that the biosurfactant produced by JD-3 was lipopeptide. The surface-active lipopeptide had a low critical micelle concentration (CMC) of 90 mg · L(-1) and presented a good ability to emulsify various hydrocarbons such as crude oil, liquid paraffin, and kerosene. Strain JD-3 could utilize peptone as nitrogen source and sucrose, glucose, glycerin or other common organics as carbon sources for anaerobic lipopeptide synthesis. The subculture of fusant JD-3 showed a stable lipopeptide-producing ability even after ten serial passages. All these results indicated that fusant JD-3 holds a great potential to microbially enhance oil recovery under anoxic conditions.

  10. Antimycoplasma properties and application in cell culture of surfactin, a lipopeptide antibiotic from Bacillus subtilis.

    PubMed

    Vollenbroich, D; Pauli, G; Ozel, M; Vater, J

    1997-01-01

    Surfactin, a cyclic lipopeptide antibiotic and biosurfactant produced by Bacillus subtilis, is well-known for its interactions with artificial and biomembrane systems (e.g., bacterial protoplasts or enveloped viruses). To assess the applicability of this antiviral and antibacterial drug, we determined the cytotoxicity of surfactin with a 50% cytotoxic concentration of 30 to 64 microM for a variety of human and animal cell lines in vitro. Concomitantly, we observed an improvement in proliferation rates and changes in the morphology of mycoplasma-contaminated mammalian cells after treatment with this drug. A single treatment over one passage led to complete removal of viable Mycoplasma hyorhinis cells from various adherent cell lines, and Mycoplasma orale was removed from nonadherent human T-lymphoid cell lines by double treatment. This effect was monitored by a DNA fluorescence test, an enzyme-linked immunosorbent assay, and two different PCR methods. Disintegration of the mycoplasma membranes as observed by electron microscopy indicated the mode of action of surfactin. Disintegration is obviously due to a physicochemical interaction of the membrane-active surfactant with the outer part of the lipid membrane bilayer, which causes permeability changes and at higher concentrations leads finally to disintegration of the mycoplasma membrane system by a detergent effect. The low cytotoxicity of surfactin for mammalian cells permits specific inactivation of mycoplasmas without significant deleterious effects on cell metabolism and the proliferation rate in cell culture. These results were used to develop a fast and simple method for complete and permanent inactivation of mycoplasmas in mammalian monolayer and suspension cell cultures.

  11. Lipopeptide als natürliche Adjuvantien für Impfstoffe aus Gram-negativen Bakterien

    NASA Astrophysics Data System (ADS)

    Schlecht, S.; Wiesmüller, K.-H.; Jung, G.; Bessler, W. G.

    1993-01-01

    Bacterial cell wall components such as lipopolysaccharide, a variety of membrane proteins, murein, and lipoprotein can act as immunoadjuvants for bacterial vaccines, thus enhancing protection from bacterial infections. Synthetically prepared N-terminal parts of the lipoprotein from Enterobacteria carrying three fatty acid residues or lipopeptide analogs containing one to four aminoacids bound to S-glycerylcysteine act as potent immunoadjuvants in vivo in combination with or covalently linked to antiges. Here we demonstrate that the supplementation of Salmonella vaccines with these synthetic lipopeptides significantly enhances their vaccine efficiency in mice. Variations in the native lipopeptide structure regarding chain length and amino acid sequence of the peptide moiety, as well as modifications of the lipoamino acid, lead to reduction or even complete loss of the adjuvant activity. The immunoadjuvant properties of the lipopeptides as described here are mediated by an enhancement of the humoral immune response.

  12. Purification and identification of Bacillus subtilis SPB1 lipopeptide biosurfactant exhibiting antifungal activity against Rhizoctonia bataticola and Rhizoctonia solani.

    PubMed

    Mnif, Inès; Grau-Campistany, Ariadna; Coronel-León, Jonathan; Hammami, Inès; Triki, Mohamed Ali; Manresa, Angeles; Ghribi, Dhouha

    2016-04-01

    This study reports the potential of a soil bacterium, Bacillus subtilis strain SPB1, to produce lipopeptide biosurfactants. Firstly, the crude lipopeptide mixture was tested for its inhibitory activity against phytopathogenic fungi. A minimal inhibitory concentration (MIC), an inhibitory concentration at 50% (IC50%), and an inhibitory concentration at 90% (IC90%) values were determined to be 0.04, 0.012, and 0.02 mg/ml, respectively, for Rhizoctonia bataticola with a fungistatic mode of action. For Rhizoctonia solani, a MIC, an IC50%, and IC90% values were determined to be 4, 0.25, and 3.3 mg/ml, respectively, with a fungicidal mode of action. For both of the fungi, a loss of sclerotial integrity, granulation and fragmentation of hyphal mycelia, followed by hyphal shriveling and cell lysis were observed with the treatment with SPB1 biosurfactant fraction. After extraction, separation, and purification, different lipopeptide compounds were identified in the culture filtrate of strain SPB1. Mass spectroscopic analysis confirmed the presence of different lipopeptide compounds consisting of surfactin isoforms with molecular weights of 1007, 1021, and 1035 Da; iturin isoforms with molecular weights of 1028, 1042, and 1056 Da; and fengycin isoforms with molecular weights of 1432 and 1446 Da. Two new clusters of lipopeptide isoforms with molecular weights of 1410 and 1424 Da and 973 and 987 Da, respectively, were also detected. This study reported the ability of a B. subtilis strain to co-produce lipopeptide isoforms with potential use as antifungal compounds.

  13. Wastewater treatment enhancement by applying a lipopeptide biosurfactant to a lignocellulosic biocomposite.

    PubMed

    Perez-Ameneiro, M; Vecino, X; Cruz, J M; Moldes, A B

    2015-10-20

    In this work, a natural lipopeptide biosurfactant obtained from corn steep liquor was included in the formulation of a lignocellulosic biocomposite used for the treatment of wastewater. The results obtained indicate that the dye sorption capacity of the hydrogel containing hydrolysed vineyard pruning waste can be significantly promoted via surfactant modification using natural detergents. The elimination of dye compounds and the removal of sulphates were increased around 10% and 62%, respectively, when the biocomposite modified with biosurfactant was used. This outcome can be intrinsically related to the rougher, rounder, more compact and better-emulsified sphere achieved after the addition of the lipopeptide biosurfactant. The bioadsorption process followed a pseudo-second order kinetic model and both intraparticle diffusion and liquid film diffusion were involved in the bioadsorption mechanism. Therefore, the utilisation of biosurfactants shows great potential in the formulation of eco-friendly adsorbents for environmental application.

  14. Cyclic lipopeptides as antibacterial agents - potent antibiotic activity mediated by intriguing mode of actions.

    PubMed

    Schneider, Tanja; Müller, Anna; Miess, Henrike; Gross, Harald

    2014-01-01

    Cyclic lipopeptides (CLPs) are a promising class of natural products with antibiotic properties. CLPs are amphiphilic molecules, composed of a fatty acid tail linked to a short oligopeptide which form a macrocylic ring structure. This review presents an overview of this class of antibiotics, focusing on the current and potential therapeutic applications and placing particular emphasis on the molecular modes of action of these compounds.

  15. Biocombinatorial Synthesis of Novel Lipopeptides by COM Domain-Mediated Reprogramming of the Plipastatin NRPS Complex

    PubMed Central

    Liu, Hongxia; Gao, Ling; Han, Jinzhi; Ma, Zhi; Lu, Zhaoxin; Dai, Chen; Zhang, Chong; Bie, Xiaomei

    2016-01-01

    Both donors and acceptors of communication-mediating (COM) domains are essential for coordinating intermolecular communication within nonribosomal peptides synthetases (NRPSs) complexes. Different sets of COM domains provide selectivity, allowing NRPSs to utilize different natural biosynthetic templates. In this study, novel lipopeptides were synthesized by reprogramming the plipastatin biosynthetic machinery. A Thr-to-Asp point mutation was sufficient to shift the selectivity of the donor COM domain of ppsB toward that of ppsD. Deletion and/or interchangeability established donor and acceptor function. Variations in acceptor COM domain did not result in novel product formation in the presence of its partner donor, whereas plipastatin formation was completely abrogated by altering donor modules. Five novel lipopeptides (cyclic pentapeptide, linear hexapeptide, nonapeptide, heptapeptide, and cyclic octapeptide) were identified and verified by high-resolution LC-ESI-MS/MS. In addition, we demonstrated the potential to generate novel strains with the antimicrobial activity by selecting compatible COM domains, and the novel lipopeptides exhibited antimicrobial activity against five of the fungal species at a contention of 31.25–125 μg/ml. PMID:27909427

  16. The Tunisian oasis ecosystem is a source of antagonistic Bacillus spp. producing diverse antifungal lipopeptides.

    PubMed

    El Arbi, Amel; Rochex, Alice; Chataigné, Gabrielle; Béchet, Max; Lecouturier, Didier; Arnauld, Ségolène; Gharsallah, Néji; Jacques, Philippe

    2016-01-01

    The use of microbial products has become a promising alternative approach to controlling plant diseases caused by phytopathogenic fungi. Bacteria isolated from the date palm tree rhizosphere of the Tunisian oasis ecosystem could provide new biocontrol microorganisms adapted to extreme conditions, such as drought, salinity and high temperature. The aim of this study was to screen bacteria isolated from the rhizosphere of the date palm tree for their ability to inhibit phytopathogenic fungi, and to identify molecules responsible for their antifungal activity. Screening for antifungal activity was performed on twenty-eight isolates. Five antagonistic isolates were selected and identified as different species of Bacillus using phenotypical methods and a molecular approach. The five antagonistic Bacillus isolated showed tolerance to abiotic stresses (high temperature, salinity, drought). Their ability to produce lipopeptides was investigated using a combination of two techniques: PCR amplification and MALDI-ToF mass spectrometry. Analyses revealed that the antagonistic isolates produced a high diversity of lipopeptides that belonged to surfactin, fengycin, iturin and kurstakin families. Their antagonistic activity, related to their capacity for producing diverse antifungal lipopeptides and their tolerance to abiotic stresses, highlighted Bacillus strains isolated from the rhizosphere of the date palm tree as potential biocontrol agents for combatting plant diseases in extreme environments.

  17. Lipopeptides as the Antifungal and Antibacterial Agents: Applications in Food Safety and Therapeutics

    PubMed Central

    Meena, Khem Raj; Kanwar, Shamsher S.

    2015-01-01

    A lot of crops are destroyed by the phytopathogens such as fungi, bacteria, and yeast leading to economic losses to the farmers. Members of the Bacillus genus are considered as the factories for the production of biologically active molecules that are potential inhibitors of growth of phytopathogens. Plant diseases constitute an emerging threat to global food security. Many of the currently available antimicrobial agents for agriculture are highly toxic and nonbiodegradable and thus cause extended environmental pollution. Moreover, an increasing number of phytopathogens have developed resistance to antimicrobial agents. The lipopeptides have been tried as potent versatile weapons to deal with a variety of phytopathogens. All the three families of Bacillus lipopeptides, namely, Surfactins, Iturins and Fengycins, have been explored for their antagonistic activities towards a wide range of phytopathogens including bacteria, fungi, and oomycetes. Iturin and Fengycin have antifungal activities, while Surfactin has broad range of potent antibacterial activities and this has also been used as larvicidal agent. Interestingly, lipopeptides being the molecules of biological origin are environmentally acceptable. PMID:25632392

  18. Efficiency of lipopeptide biosurfactants in removal of petroleum hydrocarbons and heavy metals from contaminated soil.

    PubMed

    Singh, Anil Kumar; Cameotra, Swaranjit Singh

    2013-10-01

    This study describes the potential application of lipopeptide biosurfactants in removal of petroleum hydrocarbons and heavy metals from the soil samples collected from industrial dumping site. High concentrations of heavy metals (like iron, lead, nickel, cadmium, copper, cobalt and zinc) and petroleum hydrocarbons were present in the contaminated soil samples. Lipopeptide biosurfactant, consisting of surfactin and fengycin was obtained from Bacillus subtilis A21. Soil washing with biosurfactant solution removed significant amount of petroleum hydrocarbon (64.5 %) and metals namely cadmium (44.2 %), cobalt (35.4 %), lead (40.3 %), nickel (32.2 %), copper (26.2 %) and zinc (32.07 %). Parameters like surfactant concentration, temperature, agitation condition and pH of the washing solution influenced the pollutant removing ability of biosurfactant mixture. Biosurfactant exhibited substantial hydrocarbon solubility above its critical micelle concentration. During washing, 50 % of biosurfactant was sorbed to the soil particles decreasing effective concentration during washing process. Biosurfactant washed soil exhibited 100 % mustard seed germination contradictory to water washed soil where no germination was observed. The results indicate that the soil washing with mixture of lipopeptide biosurfactants at concentrations above its critical micelle concentration can be an efficient and environment friendly approach for removing pollutants (petroleum hydrocarbon and heavy metals) from contaminated soil.

  19. Methods for the comprehensive structural elucidation of constitution and stereochemistry of lipopeptides.

    PubMed

    Gerhardt, Heike; Sievers-Engler, Adrian; Jahanshah, Ghazaleh; Pataj, Zoltán; Ianni, Federica; Gross, Harald; Lindner, Wolfgang; Lämmerhofer, Michael

    2016-01-08

    A panel of methods of general suitability for complete structural elucidation of the stereochemistry of cyclopeptides, depsipeptides and lipopeptides is presented and described in detail. The suitability of the proposed methods was exemplified on the lipopeptide poaeamide from Pseudomonas poae. Amino acid configurations have been assigned by direct LC enantiomer separation with Chiralpak ZWIX(+) and were confirmed by GC enantiomer separation on Chirasil L-Val. 3-Hydroxydecanoic acid absolute configuration was analyzed on Chiralpak ZWIX(+) and confirmed by injection on ZWIX(-) which showed opposite elution order. Plenty of d-amino acids have been found in this lipopeptide. It contained in total 5 Leu residues of which one had d-configuration. The position of the d-Leu in the peptide sequence was determined by pepsin and chemical digestions in combination with isolation of diagnostic peptide-fragments and subsequent identification of absolute configurations of the Leu residues. This allowed pinpointing the position of the d-amino acid. The complementarity of the peptide retention profiles on Chiralpak ZWIX column as compared to both RPLC and HILIC suggests its great utility as an alternative peptide separation tool.

  20. Probing the Penetration of Antimicrobial Polymyxin Lipopeptides into Gram-Negative Bacteria

    PubMed Central

    2015-01-01

    The dry antibiotic development pipeline coupled with the emergence of multidrug resistant Gram-negative ‘superbugs’ has driven the revival of the polymyxin lipopeptide antibiotics. Polymyxin resistance implies a total lack of antibiotics for the treatment of life-threatening infections. The lack of molecular imaging probes that possess native polymyxin-like antibacterial activity is a barrier to understanding the resistance mechanisms and the development of a new generation of polymyxin lipopeptides. Here we report the regioselective modification of the polymyxin B core scaffold at the N-terminus with the dansyl fluorophore to generate an active probe that mimics polymyxin B pharmacologically. Time-lapse laser scanning confocal microscopy imaging of the penetration of probe (1) into Gram-negative bacterial cells revealed that the probe initially accumulates in the outer membrane and subsequently penetrates into the inner membrane and finally the cytoplasm. The implementation of this polymyxin-mimetic probe will advance the development of platforms for the discovery of novel polymyxin lipopeptides with efficacy against polymyxin-resistant strains. PMID:24635310

  1. A Lipopeptide HIV-1/2 Fusion Inhibitor with Highly Potent in vitro, ex vivo and in vivo Antiviral Activity.

    PubMed

    Chong, Huihui; Xue, Jing; Xiong, Shengwen; Cong, Zhe; Ding, Xiaohui; Zhu, Yuanmei; Liu, Zixuan; Chen, Ting; Feng, Yifan; He, Lei; Guo, Yan; Wei, Qiang; Zhou, Yusen; Qin, Chuan; He, Yuxian

    2017-03-29

    Peptides derived from the C-terminal heptad repeat (CHR) region of the HIV-1 fusogenic protein gp41 are potent viral entry inhibitors, and currently enfuvirtide (T-20) is the only one for clinical use; however, emerging drug-resistance largely limits its efficacy. In this study, we generated a novel lipopeptide inhibitor, named LP-19, by integrating multiple design strategies, including an N-terminal M-T hook structure, HIV-2 sequence, intra-helical salt-bridges, and a membrane-anchoring lipid tail. LP-19 showed stable binding affinity and highly potent, broad and long-lasting antiviral activity. In in vitro studies, LP-19 efficiently inhibited HIV-1, HIV-2 and SIV-mediated cell fusion, viral entry and infection, and it was highly active against diverse subtypes of primary HIV-1 isolates and inhibitor-resistant mutants. The ex vivo studies demonstrated that LP-19 exhibited dramatically increased anti-HIV activity and extended half-life in rhesus macaques. In short-term monotherapy, LP-19 reduced the viral loads to undetectable levels in acutely and chronically SHIV-infected monkeys. Therefore, this study offers an ideal HIV-1/2 fusion inhibitor for clinical development and emphasizes the importance of the viral fusion step as a drug target.IMPORTANCE The peptide drug T-20 is the only viral fusion inhibitor in clinic, which is used in combination therapy of HIV-1 infection; however, it requires high dosage and easily induces drug-resistance, calling for a new drug with significantly improved pharmaceutical profiles. Here, we have developed a short lipopeptide-based fusion inhibitor termed LP-19, which mainly targets the conserved gp41 pocket site and shows highly potent inhibitory activity on HIV-1, HIV-2 and even SIV isolates. LP-19 exhibits dramatically increased antiviral activity and extended half-life in rhesus macaques, and it has potent therapeutic efficacy in SHIV-infected monkeys, highlighting its high potential as a new viral fusion inhibitor for clinical

  2. Purification and characterization of a novel lipopeptide from Streptomyces amritsarensis sp. nov. active against methicillin-resistant Staphylococcus aureus

    PubMed Central

    2014-01-01

    Nowadays antimicrobial lipopeptides are being widely exploited for developing potential therapeutic agents for treating bacterial infections. In the present study, we have purified and characterized an antimicrobial lipopeptide produced by Streptomyces amritsarensis sp. nov. (= MTCC 11845T = JCM 19660T). The lipopeptide was purified using silica gel chromatography, size exclusion chromatography and reverse phase- HPLC. The MS/MS analysis of the lipopeptide revealed that it has amino acid sequence as Ala-Thr-Gly-Ser-His-Gln and a long chain fatty acid tail with six times repeated the molecular mass of 161 Da which is corresponding to -C12H19. Based on the molecular mass (878.5 Da) and amino acid composition, the lipopeptide was identified as a novel lipopeptide. The MIC values of purified lipopeptide against Bacillus subtilis (MTCC 619), Staphylococcus epidermidis (MTCC 435), Mycobacterium smegmatis (MTCC 6) and clinical strain, Methicillin Resistant Staphylococcus aureus (MRSA) were found to be 10, 15, 25 and 45 μg/ml, respectively. It was completely stable at 70°C for 1 h and retained 81.8% activity after autoclaving (121°C for 15 min). It did not show any change in its activity profile between pH 5.0 - 9.0 and is stable to trypsin, proteinase K and lipase enzymes. It was found to be non-mutagenic against Salmonella typhimurium (TA98) and did not show cytotoxicity when checked against Chinese hamster ovary (CHO) cell line. In addition to antibacterial activity it also exhibits biosurfactant activity. PMID:25006539

  3. Cyclic lipopeptide antibiotics bind to the N-terminal domain of the prokaryotic Hsp90 to inhibit the chaperone activity.

    PubMed

    Minagawa, Shun; Kondoh, Yasumitsu; Sueoka, Keigo; Osada, Hiroyuki; Nakamoto, Hitoshi

    2011-04-01

    Chemical arrays were employed to screen ligands for HtpG, the prokaryotic homologue of Hsp (heat-shock protein) 90. We found that colistins and the closely related polymyxin B interact physically with HtpG. They bind to the N-terminal domain of HtpG specifically without affecting its ATPase activity. The interaction caused inhibition of chaperone function of HtpG that suppresses thermal aggregation of substrate proteins. Further studies were performed with one of these cyclic lipopeptide antibiotics, colistin sulfate salt. It inhibited the chaperone function of the N-terminal domain of HtpG. However, it inhibited neither the chaperone function of the middle domain of HtpG nor that of other molecular chaperones such as DnaK, the prokaryotic homologue of Hsp70, and small Hsp. The addition of colistin sulfate salt increased surface hydrophobicity of the N-terminal domain of HtpG and induced oligomerization of HtpG and its N-terminal domain. These structural changes are discussed in relation to the inhibition of the chaperone function.

  4. Synthesis and characterisation of self-assembled and self-adjuvanting asymmetric multi-epitope lipopeptides of ovalbumin.

    PubMed

    Eskandari, Sharareh; Stephenson, Rachel J; Fuaad, Abdullah Ahmad; Apte, Simon H; Doolan, Denise L; Toth, Istvan

    2015-01-12

    Designing a lipopeptide (LP) vaccine with a specific asymmetric arrangement of epitopes may result in an improved display of antigens, increasing host-cell recognition and immunogenicity. This study aimed to synthesise and characterise the physicochemical properties of a library of asymmetric LP-based vaccine candidates that contained multiple CD4(+) and CD8(+) T-cell epitopes from the model protein antigen, ovalbumin. These fully synthetic vaccine candidates were prepared by microwave-assisted solid phase peptide synthesis. The C12 or C16 lipoamino acids were coupled to the N or C terminus of the OVA CD4 peptide epitope. The OVA CD4 LPs and OVA CD8 peptide constructs were then conjugated using azide-alkyne Huisgen cycloaddition to give multivalent synthetic vaccines. Physiochemical characterisation of these vaccines showed a tendency to self-assemble in aqueous media. Changes in lipid length and position induced self-assembly with significant changes to their morphology and secondary structure as shown by transmission electron microscopy and circular dichroism.

  5. In vitro and in vivo characterization of CB-183,315, a novel lipopeptide antibiotic for treatment of Clostridium difficile.

    PubMed

    Mascio, Carmela T M; Mortin, Lawrence I; Howland, Karen T; Van Praagh, Andrew D G; Zhang, Shuxin; Arya, Anu; Chuong, Cun Lan; Kang, Chunfeng; Li, Tongchuan; Silverman, Jared A

    2012-10-01

    CB-183,315 is a novel lipopeptide antibiotic structurally related to daptomycin currently in phase 3 clinical development for Clostridium difficile-associated diarrhea (CDAD). We report here the in vitro mechanism of action, spontaneous resistance incidence, resistance by serial passage, time-kill kinetics, postantibiotic effect, and efficacy of CB-183,315 in a hamster model of lethal infection. In vitro data showed that CB-183,315 dissipated the membrane potential of Staphylococcus aureus without inducing changes in membrane permeability to small molecules. The rate of spontaneous resistance to CB-183,315 at 8× the MIC was below the limit of detection in C. difficile. Under selective pressure by serial passage with CB-183,315 against C. difficile, the susceptibility of the bacteria changed no more than 2-fold during 15 days of serial passages. At 16× the MIC, CB-183,315 produced a ≥3-log reduction of C. difficile in the time-kill assay. The postantibiotic effect of CB-183,315 at 8× the MIC was 0.9 h. At 80× the MIC the postantibiotic effect was more than 6 h. In the hamster model of CDAD, CB-183,315 and vancomycin both demonstrated potent efficacy in resolving initial disease onset, even at very low doses. After the conclusion of dosing, CB-183,315 and vancomycin showed a similar dose- and time-dependent pattern with respect to rates of CDAD recurrence.

  6. Modeling antimicrobial activity of lipopeptides from Bacillus amyloliquefaciens ES-2 against Shewanella putrefaciens in shrimp meat using a response surface method.

    PubMed

    Liu, Huanming; Sun, Lijun; Wang, Yaling; Lei, Xiaoling; Xu, Defeng

    2012-10-01

    Bacillus amyloliquefaciens ES-2 can produce antimicrobial lipopeptides, including surfactin and fengycin. In this study, the model of antimicrobial activity against Shewanella putrefaciens in shrimp meat by antimicrobial lipopeptides from B. amyloliquefaciens ES-2 was researched by response surface methodology. The results showed that S. putrefaciens had high sensitivity to antimicrobial lipopeptides, which had a MIC of 0.6 mg/ml. A quadratic mathematical model representative of the action of antimicrobial lipopeptides on S. putrefaciens in shrimp meat was developed as a function of concentration, time, and temperature. A reduction of S. putrefaciens cells of over 2 log cycles could be realized when the temperature was below 5.4°C, the time was over 6 h, and the concentration of the lipopeptides was over 0.3 mg/g.

  7. Simultaneous Determination of Absolute Configuration and Quantity of Lipopeptides Using Chiral Liquid Chromatography/Mass Spectrometry and Diastereomeric Internal Standards.

    PubMed

    Nemati, Reza; Dietz, Christopher; Anstadt, Emily; Clark, Robert; Smith, Michael; Nichols, Frank; Yao, Xudong

    2017-02-28

    Lipopeptides promote innate immune response and are related to disease pathology. To investigate the newly emerging roles of lipopeptides, accurate measurements of stereoisomers with multiple chiral centers are essential yet challenging. This work uses (3R)- and (3S)-(15-methyl-3-((13-methyltetradecanoyl)oxy)hexadecanoyl)glycyl-l-serine, abbreviated as l-serine-(R+S)-Lipid 654, to develop a method that combines chiral liquid chromatography, a diastereomeric mixture of isotopically labeled internal standards, and multiple reaction monitoring mass spectrometry. The new method allows for simultaneously determining the absolute configuration and quantity of stereoisomers of bacteria-derived lipopeptides. Total lipid extracts of nine evaluated bacteria strains had different amounts, but only the (R)-isoform of l-serine-Lipid 654. The developed method also allowed for the first quantitative analysis of hydrolysis of a nonphospholipid as a novel substrate of honey bee venom phospholipase A2.

  8. Antimicrobial and Insecticidal: Cyclic Lipopeptides and Hydrogen Cyanide Produced by Plant-Beneficial Pseudomonas Strains CHA0, CMR12a, and PCL1391 Contribute to Insect Killing

    PubMed Central

    Flury, Pascale; Vesga, Pilar; Péchy-Tarr, Maria; Aellen, Nora; Dennert, Francesca; Hofer, Nicolas; Kupferschmied, Karent P.; Kupferschmied, Peter; Metla, Zane; Ma, Zongwang; Siegfried, Sandra; de Weert, Sandra; Bloemberg, Guido; Höfte, Monica; Keel, Christoph J.; Maurhofer, Monika

    2017-01-01

    Particular groups of plant-beneficial fluorescent pseudomonads are not only root colonizers that provide plant disease suppression, but in addition are able to infect and kill insect larvae. The mechanisms by which the bacteria manage to infest this alternative host, to overcome its immune system, and to ultimately kill the insect are still largely unknown. However, the investigation of the few virulence factors discovered so far, points to a highly multifactorial nature of insecticidal activity. Antimicrobial compounds produced by fluorescent pseudomonads are effective weapons against a vast diversity of organisms such as fungi, oomycetes, nematodes, and protozoa. Here, we investigated whether these compounds also contribute to insecticidal activity. We tested mutants of the highly insecticidal strains Pseudomonas protegens CHA0, Pseudomonas chlororaphis PCL1391, and Pseudomonas sp. CMR12a, defective for individual or multiple antimicrobial compounds, for injectable and oral activity against lepidopteran insect larvae. Moreover, we studied expression of biosynthesis genes for these antimicrobial compounds for the first time in insects. Our survey revealed that hydrogen cyanide and different types of cyclic lipopeptides contribute to insecticidal activity. Hydrogen cyanide was essential to full virulence of CHA0 and PCL1391 directly injected into the hemolymph. The cyclic lipopeptide orfamide produced by CHA0 and CMR12a was mainly important in oral infections. Mutants of CMR12a and PCL1391 impaired in the production of the cyclic lipopeptides sessilin and clp1391, respectively, showed reduced virulence in injection and feeding experiments. Although virulence of mutants lacking one or several of the other antimicrobial compounds, i.e., 2,4-diacetylphloroglucinol, phenazines, pyrrolnitrin, or pyoluteorin, was not reduced, these metabolites might still play a role in an insect background since all investigated biosynthetic genes for antimicrobial compounds of strain

  9. Peptide hormones and lipopeptides: from self-assembly to therapeutic applications.

    PubMed

    Hutchinson, J A; Burholt, S; Hamley, I W

    2017-02-01

    This review describes the properties and activities of lipopeptides and peptide hormones and how the lipidation of peptide hormones could potentially produce therapeutic agents combating some of the most prevalent diseases and conditions. The self-assembly of these types of molecules is outlined, and how this can impact on bioactivity. Peptide hormones specific to the uptake of food and produced in the gastrointestinal tract are discussed in detail. The advantages of lipidated peptide hormones over natural peptide hormones are summarised, in terms of stability and renal clearance, with potential application as therapeutic agents. © 2017 The Authors Journal of Peptide Science published by European Peptide Society and John Wiley & Sons Ltd.

  10. Interaction of antimicrobial cyclic lipopeptides from Bacillus subtilis influences their effect on spore germination and membrane permeability in fungal plant pathogens.

    PubMed

    Liu, Jiajie; Hagberg, Ingrid; Novitsky, Laura; Hadj-Moussa, Hanane; Avis, Tyler J

    2014-11-01

    Bacillus subtilis cyclic lipopeptides are known to have various antimicrobial effects including different types of interactions with the cell membranes of plant pathogenic fungi. The various spectra of activities of the three main lipopeptide families (fengycins, iturins, and surfactins) seem to be linked to their respective mechanisms of action on the fungal biomembrane. Few studies have shown the combined effect of more than one family of lipopeptides on fungal plant pathogens. In an effort to understand the effect of producing multiple lipopeptide families, sensitivity and membrane permeability of spores from four fungal plant pathogens (Alternaria solani, Fusarium sambucinum, Rhizopus stolonifer, and Verticillium dahliae) were assayed in response to lipopeptides, both individually and as combined treatments. Results showed that inhibition of spores was highly variable depending on the tested fungus-lipopeptide treatment. Results also showed that inhibition of the spores was closely associated with SYTOX stain absorption suggesting effects of efficient treatments on membrane permeability. Combined lipopeptide treatments revealed additive, synergistic or sometimes mutual inhibition of beneficial effects.

  11. Acute and sub-chronic oral toxicity profiles of lipopeptides from Bacillus mojavensis A21 and evaluation of their in vitro anticoagulant activity.

    PubMed

    Ben Ayed, Hanen; Nasri, Rim; Jemil, Nawel; Ben Amor, Ikram; Gargouri, Jalel; Hmidet, Noomen; Nasri, Moncef

    2015-07-05

    The aim of the present study was to evaluate the acute and sub-chronic toxicity of lipopeptides mixture produced by Bacillus mojavensis A21 as well as their in vitro anticoagulant activity. A21 lipopeptides was given to mice at single dose from 75 mg to 1000 mg/kg body weight (bw). The median lethal dose (LD50) of A21 lipopeptides was about 550 mg/kg bw. Sub-chronic toxicity study for 28 days was done by daily oral administration of A21 lipopeptides at doses of 40 and 400 mg/kg bw in rats. Results showed that A21 lipopeptides did not cause any change in body weights and they did not produce any marked alterations in the hematological blood parameters including hematocrit concentration, hemoglobin level, white and red cells count. However, the platelets level decreased significantly compared to control value. Moreover, no significant differences in the serum biochemical characteristics were observed for rats treated by the lowest dose. In contrast, a little enhancement of alanine-aminotransferase (ALT) activity and decrease in total cholesterol were observed with the highest dose. A21 lipopeptides were also found to cause a prolongation of the thrombin time (TT), the prothrombin time (PT) and the activated partial thromboplastin time (APTT). Overall, A21 lipopeptides may be very promising compounds for therapeutic purposes.

  12. Abiogenic Syntheses of Lipoamino Acids and Lipopeptides and their Prebiotic Significance

    NASA Astrophysics Data System (ADS)

    Sproul, Gordon

    2015-12-01

    Researchers have formed peptide bonds under a variety of presumed prebiotic conditions. Here it is proposed that these same conditions would have also formed amide bonds between fatty acids and amino acids, producing phosphate-free amphipathic lipoamino acids and lipopeptides. These compounds are known to form vesicles and are ubiquitous in living organisms. They could represent molecules that provided protection by membranes as well as possibilities for proto-life metabolism . It is here demonstrated that when a fatty acid is heated with various amino acids, optimally in the presence of suitable salts or minerals, lipoamino acids are formed. Magnesium and potassium carbonates as well as iron (II) sulfide are found to be particularly useful in these reactions. In this manner N-lauroylglycine, N-lauroylalanine, N-stearoylalanine and several other lipoamino acids have been synthesized. Similarly, when glycylglycine was heated with lauric acid in the presence of magnesium carbonate, the lipopeptide N-lauroylglycylglycine was formed. Such compounds are proposed to have been critical precursors to the development of life.

  13. Enhanced production of mosquitocidal cyclic lipopeptide from Bacillus subtilis subsp. subtilis

    PubMed Central

    Manonmani, A.M.; Geetha, I.; Bhuvaneswari, S.

    2011-01-01

    Background & objectives: A cyclic lipopeptide, surfactin produced by a strain of Bacillus subtilis subsp. subtilis (VCRC B471) was found to exhibit activity against both the larval and pupal stages of mosquitoes. The present study was aimed at increasing the production of the mosquitocidal metabolite by modifying the conventional medium. Methods: Enhancement of mosquitocidal metabolite production was attempted by replacing the existing micronutrients of the conventional NYSM and supplementing the medium with additional amounts of glucose. The LC50 value of culture supernatant (CS) against the larval and pupal stages of Anopheles stephensi was determined. Crude mosquitocidal metabolite (CMM) was separated from the CS, identified by MALDI-TOF analysis and its LC50 dosage requirement for the pupal stage of the above mosquito species determined. Results: The medium containing a new composition of micronutrients and glucose up to 1 per cent resulted in increased metabolite production. The LC50 value of the CS obtained in the improved medium against larvae and pupae of An. stephensi was 5.57 and 0.71 μl/ml, respectively. The yield of CMM was doubled in the improved medium. MALDI-TOF analysis revealed that the CMM was surfactin. Interpretation & conclusions: The new improved medium enhanced the production of mosquitocidal metabolite as the dosage required for inciting 50 per cent mortality among the pupal stages of mosquitoes was only half of that required when the metabolite was produced in the conventional medium. The mosquitocidal metabolite was identified as surfactin, a cyclic lipopeptide and biosurfactant. PMID:22089610

  14. ATP binding by NLRP7 is required for inflammasome activation in response to bacterial lipopeptides.

    PubMed

    Radian, Alexander D; Khare, Sonal; Chu, Lan H; Dorfleutner, Andrea; Stehlik, Christian

    2015-10-01

    Nucleotide-binding oligimerization domain (NOD)-like receptors (NLRs) are pattern recognition receptors (PRRs) involved in innate immune responses. NLRs encode a central nucleotide-binding domain (NBD) consisting of the NAIP, CIITA, HET-E and TP1 (NACHT) domain and the NACHT associated domain (NAD), which facilitates receptor oligomerization and downstream inflammasome signaling. The NBD contains highly conserved regions, known as Walker motifs, that are required for nucleotide binding and hydrolysis. The NLR containing a PYRIN domain (PYD) 7 (NLRP7) has been recently shown to assemble an ASC and caspase-1-containing high molecular weight inflammasome complex in response to microbial acylated lipopeptides and Staphylococcus aureus infection. However, the molecular mechanism responsible for NLRP7 inflammasome activation is still elusive. Here we demonstrate that the NBD of NLRP7 is an ATP binding domain and has ATPase activity. We further show that an intact nucleotide-binding Walker A motif is required for NBD-mediated nucleotide binding and hydrolysis, oligomerization, and NLRP7 inflammasome formation and activity. Accordingly, THP-1 cells expressing a mutated Walker A motif display defective NLRP7 inflammasome activation, interleukin (IL)-1β release and pyroptosis in response to acylated lipopeptides and S. aureus infection. Taken together, our results provide novel insights into the mechanism of NLRP7 inflammasome assembly.

  15. Cyclic lipopeptides from Bacillus subtilis ABS-S14 elicit defense-related gene expression in citrus fruit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effects of cyclic lipopeptides obtained from B. subtilis ABS-S14 on eliciting defense-related gene transcription and activity of defense-related enzymes glucanase (GLU), chitinase (CHI), peroxidase (POX) and lipoxygenase (LOX) in Citrus sinensis cv. Valencia fruit were determined. The maximum level ...

  16. Self-Assembly of the Cyclic Lipopeptide Daptomycin: Spherical Micelle Formation Does Not Depend on the Presence of Calcium Chloride.

    PubMed

    Kirkham, Steven; Castelletto, Valeria; Hamley, Ian William; Inoue, Katsuaki; Rambo, Robert; Reza, Mehedi; Ruokolainen, Janne

    2016-07-18

    The cyclic lipopeptide Daptomycin, used as a treatment for infections where antimicrobial resistance is observed, is shown to self-assemble into spherical micelles above a critical aggregation concentration. Micelles are observed either in the absence or presence of CaCl2 , in contrast to claims in the literature that CaCl2 is required for micellization.

  17. Interactions between lipid-free apolipoprotein-AI and a lipopeptide incorporating the RGDS cell adhesion motif

    NASA Astrophysics Data System (ADS)

    Castelletto, V.; Hamley, I. W.; Reza, M.; Ruokolainen, J.

    2014-11-01

    The interaction of a designed bioactive lipopeptide C16-GGGRGDS, comprising a hexadecyl lipid chain attached to a functional heptapeptide, with the lipid-free apoliprotein, Apo-AI, is examined. This apolipoprotein is a major component of high density lipoprotein and it is involved in lipid metabolism and may serve as a biomarker for cardiovascular disease and Alzheimers' disease. We find via isothermal titration calorimetry that binding between the lipopeptide and Apo-AI occurs up to a saturation condition, just above equimolar for a 10.7 μM concentration of Apo-AI. A similar value is obtained from circular dichroism spectroscopy, which probes the reduction in α-helical secondary structure of Apo-AI upon addition of C16-GGGRGDS. Electron microscopy images show a persistence of fibrillar structures due to self-assembly of C16-GGGRGDS in mixtures with Apo-AI above the saturation binding condition. A small fraction of spheroidal or possibly ``nanodisc'' structures was observed. Small-angle X-ray scattering (SAXS) data for Apo-AI can be fitted using a published crystal structure of the Apo-AI dimer. The SAXS data for the lipopeptide/Apo-AI mixtures above the saturation binding conditions can be fitted to the contribution from fibrillar structures coexisting with flat discs corresponding to Apo-AI/lipopeptide aggregates.

  18. Biological control of Rhizoctonia root rot on bean by phenazine- and cyclic lipopeptide-producing Pseudomonas CMR12a

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pseudomonas CMR12a was previously selected as an efficient biocontrol strain producing phenazines and cyclic lipopeptides (CLPs). In this study, biocontrol capacity of Pseudomonas CMR12a against Rhizoctonia root rot of bean and the involvement of phenazines and CLPs in this ability were tested. Two ...

  19. A genital tract peptide epitope vaccine targeting TLR-2 efficiently induces local and systemic CD8 + T cells and protects against herpes simplex virus type 2 challenge

    PubMed Central

    Dasgupta, G; Nesburn, AB; Wu, M; Zhu, X; Carpenter, D; Wechsler, SL; You, S; BenMohamed, L

    2015-01-01

    The next generation of needle-free mucosal vaccines is being rationally designed according to rules that govern the way in which the epitopes are recognized by and stimulate the genital mucosal immune system. We hypothesized that synthetic peptide epitopes extended with an agonist of Toll-like receptor 2 (TLR-2), that are abundantly expressed by dendritic and epithelial cells of the vaginal mucosa, would lead to induction of protective immunity against genital herpes. To test this hypothesis, we intravaginally (IVAG) immunized wild-type B6, TLR-2 (TLR2 −/−) or myeloid differentiation factor 88 deficient (MyD88 −/−) mice with a herpes simplex virus type 2 (HSV-2) CD8 + T-cell peptide epitope extended by a palmitic acid moiety (a TLR-2 agonist). IVAG delivery of the lipopeptide generated HSV-2-specific memory CD8 + cytotoxic T cells both locally in the genital tract draining lymph nodes and systemically in the spleen. Moreover, lipopeptide-immunized TLR2 −/− and MyD88 −/− mice developed significantly less HSV-specific CD8 + T-cell response, earlier death, faster disease progression, and higher vaginal HSV-2 titers compared to lipopeptide-immunized wild-type B6 mice. IVAG immunization with self-adjuvanting lipid-tailed peptides appears to be a novel mucosal vaccine approach, which has attractive practical and immunological features. PMID:19129756

  20. Lipopeptide Nanoparticles: Development of Vaccines against Hookworm Parasite.

    PubMed

    Fuaad, Abdullah A H Ahmad; Pearson, Mark S; Pickering, Darren A; Becker, Luke; Zhao, Guangzu; Loukas, Alex C; Skwarczynski, Mariusz; Toth, Istvan

    2015-10-01

    Necator americanus (hookworm) infects over half a billion people worldwide. Anthelminthic drugs are commonly used to treat the infection; however, vaccination is a more favorable strategy to combat this parasite. We designed new B-cell peptide epitopes based on the aspartic protease of N. americanus (Na-APR-1). The peptides were conjugated to self-adjuvanting lipid core peptide (LCP) systems via stepwise solid-phase peptide synthesis (SPPS) and copper catalyst azide-alkyne cycloaddition (CuAAC) reactions. The LCP vaccine candidates were able to self-assemble into nanoparticles, were administered to mice without the use of additional adjuvant, and generated antibodies that recognized the parent epitope. However, only one LCP derivative was able to produce a high titer of antibodies specific to Na-APR-1; circular dichroism analyses of this compound showed a β-sheet conformation for the incorporated epitope. This study provides important insight in epitope and delivery system design for the development of a vaccine against hookworm infections.

  1. Induced topological pressure for topological dynamical systems

    SciTech Connect

    Xing, Zhitao; Chen, Ercai

    2015-02-15

    In this paper, inspired by the article [J. Jaerisch et al., Stochastics Dyn. 14, 1350016, pp. 1-30 (2014)], we introduce the induced topological pressure for a topological dynamical system. In particular, we prove a variational principle for the induced topological pressure.

  2. Production and characterization of Iturinic lipopeptides as antifungal agents and biosurfactants produced by a marine pinctada martensii-derived Bacillus mojavensis B0621A.

    PubMed

    Ma, Zongwang; Hu, Jiangchun

    2014-06-01

    Bacillus mojavensis B0621A was isolated from a pearl oyster Pinctada martensii collected from South China Sea. While screening for cyclic lipopeptides potentially useful as lead compounds for biological control against soil-bone fungal plant pathogens, three lipopeptides were isolated and purified from the fermentation broth of B. mojavensis B0621A via vacuum flash chromatography coupled with reversed-phase high performance liquid chromatography (RP-HPLC). The structural characterization and identification of these cyclic lipopeptides were performed by tandem mass spectrometry (MS/MS) combined with gas chromatography-mass spectrometry (GC-MS) analysis as well as chemical degradation. These lipopeptides were finally characterized as homologues of mojavensins, which contained identical amino acids back bones of asparagine1, tyrosine2, asparagine3, glutamine4, proline5, asparagine6, and asparagine7 and differed from each other by their saturated β-amino fatty acid chain residues, namely, iso-C14 mojavensin, iso-C16 mojavensin, and anteiso-C17 mojavensin, respectively. All lipopeptide isomers, especially iso-C16 mojavensin and anteiso-C17 mojavensin, displayed moderate antagonism and dose-dependent activity against several formae speciales of Fusarium oxysporum and presented surface tension activities. These properties demonstrated that the lipopeptides produced by B. mojavensis B0621A may be useful as biological control agent to fungal plant pathogens.

  3. Toll-like receptors are part of the innate immune defense system of sponges (demospongiae: Porifera).

    PubMed

    Wiens, Matthias; Korzhev, Michael; Perovic-Ottstadt, Sanja; Luthringer, Bérengère; Brandt, David; Klein, Stefanie; Müller, Werner E G

    2007-03-01

    During evolution and with the emergence of multicellular animals, the need arose to ward off foreign organisms that threaten the integrity of the animal body. Among many different receptors that participate in the recognition of microbial invaders, toll-like receptors (TLRs) play an essential role in mediating the innate immune response. After binding distinct microbial components, TLRs activate intracellular signaling cascades that result in an induced expression of diverse antimicrobial molecules. Because sponges (phylum Porifera) are filter feeders, they are abundantly exposed to microorganisms that represent a potential threat. Here, we describe the identification, cloning, and deduced protein sequence from 3 major elements of the poriferan innate response (to bacterial lipopeptides): the TLR, the IL-1 receptor-associated kinase-4-like protein (IRAK-4l), and a novel effector caspase from the demosponge Suberites domuncula. Each molecule shares significant sequence similarity with its homologues in higher Metazoa. Sequence homologies were found in particular within the family-specific domains toll/interleukin-1 receptor/resistance (TLR family), Ser/Thr/Tyr kinase domain (IRAK family), and CASc (caspase family). In addition, in situ hybridization and immunohistological analyses revealed an abundance of SDTLR (TLR) transcripts in epithelial layers of the sponge surface (exopinacoderm and endopinacoderm). Furthermore, it is shown that both SDTLR and SDIRAK-4 like (IRAK) are expressed constitutively, regardless of treatment with synthetic triacyl lipopeptide Pam(3)Cys-Ser-(Lys)(4). In contrast, SDCASL (caspase) expression is highly Pam(3)Cys-Ser-(Lys)(4) inducible. However, blocking of the lipopeptide with recombinant TLR prior to its application completely prevented the induced expression of this poriferan caspase. These results underscore that the phylogenetically oldest extant metazoan phylum is provided already with the signaling pathways of the antimicrobial

  4. Cyclic Lipopeptides with Herbicidal and Insecticidal Activities Produced by Bacillus clausii DTM1.

    PubMed

    Guo, Da-Le; Wan, Bo; Xiao, Shi-Ji; Allen, Sarah; Gu, Yu-Cheng; Ding, Li-Sheng; Zhoua, Yan

    2015-12-01

    Seven cyclic lipopeptide biosurfactants (1-7) were isolated for the first time from the fermentation broth of endophytic Bacillus clausii DTM1 and were identified as anteisoC13[Val7] surfactin-(L-Glu)-O-methyl-ester (1), anteisoC12[Val7] surfactin (2), anteisoC15[Val7] surfactin (3), isoC14[Leu7] surfactin (4), anteisoC12[Leu7] surfactin (5), nC13[Leu7] surfactin (6), and anteisoC14[Leu7] surfactin-(L-Glu)-O-methyl-ester (7); 1 has not been isolated before as a natural product from any source. Plate-based herbicide and insecticide bioassays showed that all compounds exhibited interesting insecticidal and herbicidal activities.

  5. Antimicrobial lipopeptide tridecaptin A1 selectively binds to Gram-negative lipid II

    PubMed Central

    Cochrane, Stephen A.; Findlay, Brandon; Bakhtiary, Alireza; Acedo, Jeella Z.; Rodriguez-Lopez, Eva M.; Mercier, Pascal; Vederas, John C.

    2016-01-01

    Tridecaptin A1 (TriA1) is a nonribosomal lipopeptide with selective antimicrobial activity against Gram-negative bacteria. Here we show that TriA1 exerts its bactericidal effect by binding to the bacterial cell-wall precursor lipid II on the inner membrane, disrupting the proton motive force. Biochemical and biophysical assays show that binding to the Gram-negative variant of lipid II is required for membrane disruption and that only the proton gradient is dispersed. The NMR solution structure of TriA1 in dodecylphosphocholine micelles with lipid II has been determined, and molecular modeling was used to provide a structural model of the TriA1–lipid II complex. These results suggest that TriA1 kills Gram-negative bacteria by a mechanism of action using a lipid-II–binding motif. PMID:27688760

  6. Antimicrobial lipopeptide tridecaptin A1 selectively binds to Gram-negative lipid II.

    PubMed

    Cochrane, Stephen A; Findlay, Brandon; Bakhtiary, Alireza; Acedo, Jeella Z; Rodriguez-Lopez, Eva M; Mercier, Pascal; Vederas, John C

    2016-10-11

    Tridecaptin A1 (TriA1) is a nonribosomal lipopeptide with selective antimicrobial activity against Gram-negative bacteria. Here we show that TriA1 exerts its bactericidal effect by binding to the bacterial cell-wall precursor lipid II on the inner membrane, disrupting the proton motive force. Biochemical and biophysical assays show that binding to the Gram-negative variant of lipid II is required for membrane disruption and that only the proton gradient is dispersed. The NMR solution structure of TriA1 in dodecylphosphocholine micelles with lipid II has been determined, and molecular modeling was used to provide a structural model of the TriA1-lipid II complex. These results suggest that TriA1 kills Gram-negative bacteria by a mechanism of action using a lipid-II-binding motif.

  7. Peptide hormones and lipopeptides: from self‐assembly to therapeutic applications

    PubMed Central

    Hutchinson, J. A.; Burholt, S.

    2017-01-01

    This review describes the properties and activities of lipopeptides and peptide hormones and how the lipidation of peptide hormones could potentially produce therapeutic agents combating some of the most prevalent diseases and conditions. The self‐assembly of these types of molecules is outlined, and how this can impact on bioactivity. Peptide hormones specific to the uptake of food and produced in the gastrointestinal tract are discussed in detail. The advantages of lipidated peptide hormones over natural peptide hormones are summarised, in terms of stability and renal clearance, with potential application as therapeutic agents. © 2017 The Authors Journal of Peptide Science published by European Peptide Society and John Wiley & Sons Ltd. PMID:28127868

  8. Application of lipopeptide biosurfactant isolated from a halophile: Bacillus tequilensis CH for inhibition of biofilm.

    PubMed

    Pradhan, Arun Kumar; Pradhan, Nilotpala; Mall, Gangotri; Panda, Himadri Tanaya; Sukla, Lala Behari; Panda, Prasanna Kumar; Mishra, Barada Kanta

    2013-11-01

    Biosurfactants are amphiphilic molecules having hydrophobic and hydrophilic moieties produced by various microorganisms. These molecules trigger the reduction of surface tension or interfacial tension in liquids. A biosurfactant-producing halophile was isolated from Lake Chilika, a brackish water lake of Odisha, India (19°41'39″N, 85°18'24″E). The halophile was identified as Bacillus tequilensis CH by biochemical tests and 16S rRNA gene sequencing and assigned accession no. KC851857 by GenBank. The biosurfactant produced by B. tequilensis CH was partially characterized as a lipopeptide using thin-layer chromatography, Fourier transform infrared spectroscopy, and nuclear magnetic resonance techniques. The minimum effective concentration of a biosurfactant for inhibition of pathogenic biofilm (Escherichia coli and Streptococcus mutans) on hydrophilic and hydrophobic surfaces was found to be 50 μg ml(-1). This finding has potential for a variety of applications.

  9. Crystal structure of a self-assembling lipopeptide detergent at 1.20 Å

    SciTech Connect

    Ho, Dona N.; Pomroy, Neil C.; Cuesta-Seijo, Jose A.; Prive, Gilbert G.

    2008-10-21

    Lipopeptide detergents (LPDs) are a new class of amphiphile designed specifically for the structural study of integral membrane proteins. The LPD monomer consists of a 25-residue peptide with fatty acyl chains linked to side chains located at positions 2 and 24 of the peptide. LPDs are designed to form {alpha}-helices that self-assemble into cylindrical micelles, providing a more natural interior acyl chain packing environment relative to traditional detergents. We have determined the crystal structure of LPD-12, an LPD coupled to two dodecanoic acids, to a resolution of 1.20 {angstrom}. The LPD-12 monomers adopt the target conformation and associate into cylindrical octamers as expected. Pairs of helices are strongly associated as Alacoil-type antiparallel dimers, and four of these dimers interact through much looser contacts into assemblies with approximate D{sub 2} symmetry. The aligned helices form a cylindrical shell with a hydrophilic exterior that protects an interior hydrophobic cavity containing the 16 LPD acyl chains. Over 90% of the methylene/methyl groups from the acylated side chains are visible in the micelle interiors, and {approx}90% of these adopt trans dihedral angle conformations. Dodecylmaltoside (DDM) was required for the crystallization of LPD-12, and we find 10-24 ordered DDM molecules associated with each LPD assembly, resulting in an overall micelle molecular weight of {approx}30 kDa. The structures confirm the major design objectives of the LPD framework, and reveal unexpected features that will be helpful in the engineering additional versions of lipopeptide amphiphiles.

  10. Hyper-inducible expression system for streptomycetes.

    PubMed

    Herai, Sachio; Hashimoto, Yoshiteru; Higashibata, Hiroki; Maseda, Hideaki; Ikeda, Haruo; Omura, Satoshi; Kobayashi, Michihiko

    2004-09-28

    Streptomycetes produce useful enzymes and a wide variety of secondary metabolites with potent biological activities (e.g., antibiotics, immunosuppressors, pesticides, etc.). Despite their importance in the pharmaceutical and agrochemical fields, there have been no reports for practical expression systems in streptomycetes. Here, we developed a "P(nitA)-NitR" system for regulatory gene expression in streptomycetes based on the expression mechanism of Rhodococcus rhodochrous J1 nitrilase, which is highly induced by an inexpensive and safe inducer, epsilon-caprolactam. Heterologous protein expression experiments demonstrated that the system allowed suppressed basal expression and hyper-inducible expression, yielding target protein levels of as high as approximately 40% of all soluble protein. Furthermore, the system functioned in important streptomycete strains. Thus, the P(nitA)-NitR system should be a powerful tool for improving the productivity of various useful products in streptomycetes.

  11. In silico analysis of nonribosomal peptide synthetases of Xanthomonas axonopodis pv. citri: identification of putative siderophore and lipopeptide biosynthetic genes.

    PubMed

    Etchegaray, Augusto; Silva-Stenico, Maria E; Moon, David H; Tsai, Siu M

    2004-01-01

    The genomes of the plant pathogens Xanthomonas axonopodis (Xac) and Xanthomonas campestris (Xcc) were analysed with the aim of deducing their ability to produce nonribosomal peptides. Nonribosomal peptide synthetase (NRPS) genes were identified in two separate loci of Xac. While the genes of locus 1 are common to both strains, locus 2 was only found in Xac. Dissection and phylogenetic analysis of the condensation and thioesterase domains of the NRPSs of loci 1 and 2 of Xac revealed homology, respectively, with siderophore and lipopeptide synthetases. Further analysis of locus 1 revealed genes related to polyketide and polyamine biosynthesis that could be involved in the assembly of substrates for siderophore biosynthesis in both strains. In vitro production of siderophores by both Xac and Xcc was confirmed. Since bacterial siderophores and lipopeptides can be pathogenic and are typically produced nonribosomally, these results suggest that the identified genes could be involved in phytotoxin production.

  12. Production and characterization of lipopeptide biosurfactant by a sponge-associated marine actinomycetes Nocardiopsis alba MSA10.

    PubMed

    Gandhimathi, R; Seghal Kiran, G; Hema, T A; Selvin, Joseph; Rajeetha Raviji, T; Shanmughapriya, S

    2009-10-01

    A sponge-associated marine actinomycetes Nocardiopsis alba MSA10 was screened and evaluated for the production of biosurfactant. Biosurfactant production was confirmed by conventional screening methods including hemolytic activity, drop collapsing test, oil displacement method, lipase production and emulsification index. The active compound was extracted with three solvents including ethyl acetate, diethyl ether and dichloromethane. The diethyl ether extract was fractionated by TLC and semi-preparative HPLC to isolate the pure compound. In TLC, a single discrete spot was obtained with the R (f) 0.60 and it was extrapolated as valine. Based on the chemical characterization, the active compound was partially confirmed as lipopeptide. The optimum production was attained at pH 7, temperature 30 degrees C, and 1% salinity with glucose and peptone supplementation as carbon and nitrogen sources, respectively. Considering the biosurfactant production potential of N. alba, the strain could be developed for large-scale production of lipopeptide biosurfactant.

  13. Mass spectrometry identification of antifungal lipopeptides from Bacillus sp. BCLRB2 against Rhizoctonia solani and Sclerotinia sclerotiorum.

    PubMed

    Elkahoui, S; Djébali, N; Karkouch, I; Ibrahim, A Hadj; Kalai, L; Bachkovel, S; Tabbene, O; Limam, F

    2014-01-01

    This work aims to characterize the bioactive molecules produced by an antagonistic Bacillus sp. strain BCLRB2 isolated from healthy leaves of olive tree against Rhizoctonia solani and Sclerotinia sclerotiorum. The bacterial strain isolated showed a high and persistent antifungal activity against the two pathogens. The free-cell supernatant showed also a high antifungal activity against R. solani and at a lower extent against S. sclerotiorum. The partial purification of the antifungal substances with methanol gradient applied to C18 column binding the Bacillus BCLRB2 culture supernatant showed that the 20% and 60% methanol fractions had a high and specific activity against S. sclerotiorum and R. solani, respectively. The mass spectrometry identification of the compounds in the fraction specifically active against S. sclerotiorum revealed the presence of bacillomycin D C16 as a major lipopeptide. The fraction specifically active against R. solani contained bacillomycin D C15 and 2 unknown lipopeptides. The 80% methanol fraction had a moderate and a broad spectrum activity against the two pathogens and consisted from two iturin D (C13 and C14) as a major lipopeptides.

  14. Antifungal efficiency of a lipopeptide biosurfactant derived from Bacillus subtilis SPB1 versus the phytopathogenic fungus, Fusarium solani.

    PubMed

    Mnif, Ines; Hammami, Ines; Triki, Mohamed Ali; Azabou, Manel Cheffi; Ellouze-Chaabouni, Semia; Ghribi, Dhouha

    2015-11-01

    Bacillus subtilis SPB1 lipopeptides were evaluated as a natural antifungal agent against Fusarium solani infestation. In vitro antifungal assay showed a minimal inhibitory concentration of about 3 mg/ml with a fungicidal mode of action. In fact, treatment of F. solani by SPB1 lipopeptides generated excessive lyses of the mycelium and caused polynucleation and destruction of the related spores together with a total inhibition of spore production. Furthermore, an inhibition of germination potency accompanied with a high spore blowing was observed. Moreover, in order to be applied in agricultural field, in vivo antifungal activity was proved against the dry rot potato tubers caused by F. solani. Preventive treatment appeared as the most promising as after 20 days of fungi inoculation, rot invasion was reduced by almost 78%, in comparison to that of non-treated one. When treating infected tomato plants, disease symptoms were reduced by almost 100% when applying the curative method. Results of this study are very promising as it enables the use of the crude lipopeptide preparation of B. subtilis SPB1 as a potent natural fungicide that could effectively control the infection of F. solani in tomato and potato tubers at a concentration similar to the commercial fungicide hymexazol and therefore prevent the damage of olive tree.

  15. Inducing amnesia through systemic suppression

    PubMed Central

    Hulbert, Justin C.; Henson, Richard N.; Anderson, Michael C.

    2016-01-01

    Hippocampal damage profoundly disrupts the ability to store new memories of life events. Amnesic windows might also occur in healthy people due to disturbed hippocampal function arising during mental processes that systemically reduce hippocampal activity. Intentionally suppressing memory retrieval (retrieval stopping) reduces hippocampal activity via control mechanisms mediated by the lateral prefrontal cortex. Here we show that when people suppress retrieval given a reminder of an unwanted memory, they are considerably more likely to forget unrelated experiences from periods surrounding suppression. This amnesic shadow follows a dose-response function, becomes more pronounced after practice suppressing retrieval, exhibits characteristics indicating disturbed hippocampal function, and is predicted by reduced hippocampal activity. These findings indicate that stopping retrieval engages a suppression mechanism that broadly compromises hippocampal processes and that hippocampal stabilization processes can be interrupted strategically. Cognitively triggered amnesia constitutes an unrecognized forgetting process that may account for otherwise unexplained memory lapses following trauma. PMID:26977589

  16. Induced Systemic Resistance by Beneficial Microbes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Beneficial microbes in the microbiome of plant roots improve plant health. Induced systemic esistance (ISR) emerged as an important mechanism by which selected plant growth–promoting bacteria and fungi in the rhizosphere prime the whole plant body for enhanced defense against a broad range of pathog...

  17. Amphiphilic Lipopeptide-Mediated Transport of Insulin and Cell Membrane Penetration Mechanism.

    PubMed

    Zhang, Yu; Li, Lei; Han, Mei; Hu, Jiaoyin; Zhang, Liefeng

    2015-12-03

    Arginine octamer (R8) and its derivatives were developed in this study for the enhanced mucosal permeation of insulin. R8 was substituted with different aminos, then modified with stearic acid (SA). We found that the SAR6EW-insulin complex had stronger intermolecular interactions and higher complex stability. The amphiphilic lipopeptide (SAR6EW) was significantly more efficient for the permeation of insulin than R8 and R6EW both in vitro and in vivo. Interestingly, different cellular internalization mechanisms were observed for the complexes. When the effectiveness of the complexes in delivering insulin in vivo was examined, it was found that the SAR6EW-insulin complex provided a significant and sustained (six hours) reduction in the blood glucose levels of diabetic rats. The improved absorption could be the comprehensive result of stronger intermolecular interactions, better enzymatic stability, altered internalization pathways, and increased transportation efficacy. In addition, no sign of toxicity was observed after consecutive administrations of SAR6EW. These results demonstrate that SAR6EW is a promising epithelium permeation enhancer for insulin and suggest that the chemical modification of cell-penetrating peptides is a feasible strategy to enhance their potential.

  18. Synergistic fungicidal activity of the lipopeptide bacillomycin D with amphotericin B against pathogenic Candida species.

    PubMed

    Tabbene, Olfa; Di Grazia, Antonio; Azaiez, Sana; Ben Slimene, Imen; Elkahoui, Salem; Alfeddy, Mohamed Najib; Casciaro, Bruno; Luca, Vincenzo; Limam, Ferid; Mangoni, Maria Luisa

    2015-06-01

    In the present study, the synergism of the lipopeptide bacillomycin D in combination with the polyene amphotericin B against pathogenic Candida species is described along with their potential cytotoxicity against mammalian cells. Bacillomycin D inhibited the growth of various Candida species at minimal concentrations from 12.5 to 25 μg ml(-1). Furthermore, it showed a synergistic effect with the antifungal drug amphotericin B in inhibiting the growth of Candida strains, with fractional inhibitory concentration indices ranging from 0.28 to 0.5. Time killing studies revealed a >2-log reduction in the viability of Candida albicans ATCC 10231 cells after 3 h incubation with the combination amphotericin B plus bacillomycin D, at their subinhibitory concentration. Interestingly, when the two drugs were used together at those dosages displaying a synergism in the anti-Candida activity, no cytotoxic effect was observed against mammalian cells. Therefore, the combination bacillomycin D/amphotericin B may represent a valid alternative to conventional antifungals for topical treatment of C. albicans infections. To the best of our knowledge, this is the first report describing the in vitro interaction between the antifungal drug amphotericin B and bacillomycin D against pathogenic Candida species.

  19. Lipopeptides as main ingredients for inhibition of fungal phytopathogens by Bacillus subtilis/amyloliquefaciens

    PubMed Central

    Cawoy, Hélène; Debois, Delphine; Franzil, Laurent; De Pauw, Edwin; Thonart, Philippe; Ongena, Marc

    2015-01-01

    Some isolates of the Bacillus subtilis/amyloliquefaciens species are known for their plant protective activity against fungal phytopathogens. It is notably due to their genetic potential to form an impressive array of antibiotics including non-ribosomal lipopeptides (LPs). In the work presented here, we wanted to gain further insights into the relative role of these LPs in the global antifungal activity of B. subtilis/amyloliquefaciens. To that end, a comparative study was conducted involving multiple strains that were tested against four different phytopathogens. We combined various approaches to further exemplify that secretion of those LPs is a crucial trait in direct pathogen ward off and this can actually be generalized to all members of these species. Our data illustrate that for each LP family, the fungitoxic activity varies in function of the target species and that the production of iturins and fengycins is modulated by the presence of pathogens. Our data on the relative involvement of these LPs in the biocontrol activity and modulation of their production are discussed in the context of natural conditions in the rhizosphere. PMID:25529983

  20. Lipopeptide production by Bacillus subtilis R1 and its possible applications.

    PubMed

    Jha, Sujata S; Joshi, Sanket J; S J, Geetha

    The possible application of a bacterial strain - Bacillus subtilis R1, isolated from an oil contaminated desert site in India, as biocontrol agent and its biosurfactant in microbial enhanced oil recovery are discussed. The biosurfactant production in minimal medium was carried out at different temperatures and salt concentrations, where it produced an efficient biosurfactant at 30-45°C and in presence of up to 7% salt. It significantly reduced the surface tension from 66±1.25mN/m to 29±0.85mN/m within 24h. In order to enhance the biosurfactant production, random mutagenesis of B. subtilis R1 was performed using chemical mutagen - ethyl methanesulfonate. Majority of the isolated 42 mutants showed biosurfactant production, but the difference was statistically insignificant as compared with parent strain R1. Therefore none of the mutants were selected for further study, and only parent strain R1 was studied. The biosurfactant was quite stable under harsh conditions for up to 10 days. The biosurfactant was extracted and characterized as similar to the lipopeptide group - surfactins and fengycin. The crude oil displacement experiments using biosurfactant broth in sand pack glass columns showed 33±1.25% additional oil recovery. The strain also showed inhibition of various plant pathogenic fungi on potato dextrose agar medium.

  1. Nonribosomal peptide synthase gene clusters for lipopeptide biosynthesis in Bacillus subtilis 916 and their phenotypic functions.

    PubMed

    Luo, Chuping; Liu, Xuehui; Zhou, Huafei; Wang, Xiaoyu; Chen, Zhiyi

    2015-01-01

    Bacillus cyclic lipopeptides (LPs) have been well studied for their phytopathogen-antagonistic activities. Recently, research has shown that these LPs also contribute to the phenotypic features of Bacillus strains, such as hemolytic activity, swarming motility, biofilm formation, and colony morphology. Bacillus subtilis 916 not only coproduces the three families of well-known LPs, i.e., surfactins, bacillomycin Ls (iturin family), and fengycins, but also produces a new family of LP called locillomycins. The genome of B. subtilis 916 contains four nonribosomal peptide synthase (NRPS) gene clusters, srf, bmy, fen, and loc, which are responsible for the biosynthesis of surfactins, bacillomycin Ls, fengycins, and locillomycins, respectively. By studying B. subtilis 916 mutants lacking production of one, two, or three LPs, we attempted to unveil the connections between LPs and phenotypic features. We demonstrated that bacillomycin Ls and fengycins contribute mainly to antifungal activity. Although surfactins have weak antifungal activity in vitro, the strain mutated in srfAA had significantly decreased antifungal activity. This may be due to the impaired productions of fengycins and bacillomycin Ls. We also found that the disruption of any LP gene cluster other than fen resulted in a change in colony morphology. While surfactins and bacillomycin Ls play very important roles in hemolytic activity, swarming motility, and biofilm formation, the fengycins and locillomycins had little influence on these phenotypic features. In conclusion, B. subtilis 916 coproduces four families of LPs which contribute to the phenotypic features of B. subtilis 916 in an intricate way.

  2. Genome mining: Prediction of lipopeptides and polyketides from Bacillus and related Firmicutes

    PubMed Central

    Aleti, Gajender; Sessitsch, Angela; Brader, Günter

    2015-01-01

    Bacillus and related genera in the Bacillales within the Firmicutes harbor a variety of secondary metabolite gene clusters encoding polyketide synthases and non-ribosomal peptide synthetases responsible for remarkable diverse number of polyketides (PKs) and lipopeptides (LPs). These compounds may be utilized for medical and agricultural applications. Here, we summarize the knowledge on structural diversity and underlying gene clusters of LPs and PKs in the Bacillales. Moreover, we evaluate by using published prediction tools the potential metabolic capacity of these bacteria to produce type I PKs or LPs. The huge sequence repository of bacterial genomes and metagenomes provides the basis for such genome-mining to reveal the potential for novel structurally diverse secondary metabolites. The otherwise cumbersome task to isolate often unstable PKs and deduce their structure can be streamlined. Using web based prediction tools, we identified here several novel clusters of PKs and LPs from genomes deposited in the database. Our analysis suggests that a substantial fraction of predicted LPs and type I PKs are uncharacterized, and their functions remain to be studied. Known and predicted LPs and PKs occurred in the majority of the plant associated genera, predominantly in Bacillus and Paenibacillus. Surprisingly, many genera from other environments contain no or few of such compounds indicating the role of these secondary metabolites in plant-associated niches. PMID:25893081

  3. Isolation of a Paenibacillus sp. Strain and Structural Elucidation of Its Broad-Spectrum Lipopeptide Antibiotic

    PubMed Central

    Guo, Yaoqi; Huang, En; Yuan, Chunhua; Zhang, Liwen

    2012-01-01

    This research was initiated to search for novel antimicrobial compounds produced by food or environmental microorganisms. A new bacterial strain, designated OSY-SE, which produces a unique and potent antimicrobial agent was isolated from soil. The isolate was identified as a Paenibacillus sp. through cultural, biochemical, and genetic analyses. An antimicrobial compound was extracted from Paenibacillus OSY-SE with acetonitrile and purified using liquid chromatography. After analyses by mass spectrometry (MS) and nuclear magnetic resonance (NMR), the antimicrobial compound was determined to be a cyclic lipopeptide consisting of a C15 fatty acyl (FA) chain and 13 amino acids. The deduced sequence is FA-Orn-Val-Thr-Orn-Ser-Val-Lys-Ser-Ile-Pro-Val-Lys-Ile. The carboxyl-terminal Ile is connected to Thr by ester linkage. The new compound, designated paenibacterin, showed antagonistic activities against most Gram-positive and Gram-negative bacteria tested, including Listeria monocytogenes, methicillin-resistant Staphylococcus aureus, Escherichia coli O157:H7, and Salmonella enterica serovar Typhimurium. Paenibacterin is resistant to trypsin, lipase, α-glucosidase, and lysozyme. Its antimicrobial activity was lost after digestion by pronase and polymyxin acylase. Paenibacterin is readily soluble in water and fairly stable to exposure to heat and a wide range of pH values. The new isolate and its antimicrobial agent are being investigated for usefulness in food and medical applications. PMID:22367082

  4. Biofilm formation and lipopeptide antibiotic iturin A production in different peptone media.

    PubMed

    Zohora, Umme Salma; Rahman, Mohammad Shahedur; Ano, Takashi

    2009-01-01

    Biofilm fermentation is a newly developed promising technique in fermentation technology. In this study no.3 and no.3S media have been used for the lipopeptide antibiotic iturin A production by Bacillus subtilis RB14. The main component of no.3 and no.3S media is Polypepton and Polypepton S, respectively. B. subtilis RB14 produces thick stable biofilm and high amount of iturin A in no.3S medium. Whereas, impaired biofilm formation and lower iturin A production was observed in no.3 medium. From the analytical information it was observed that the amounts of metal ions, such as K(+), Ca(2+) and Mn(2+), cysteine and cellulose are lower in Polypepton compared to the Polypepton S. To investigate their effect on biofilm formation and iturin A production cysteine, cellulose, K(+), Ca(2+) and Mn(2+) were added respectively into the no.3 medium at similar amount that Polypepton S contains. It was observed that individual addition of K(+), Ca(2+), cysteine and cellulose had no effect on biofilm formation, cellular growth induction or iturin A production. However, when Mn(2+) was supplemented in no.3 medium, biofilm development was restored with an improved production of iturin A. Finally, combined addition of investigated substances into the no.3 medium resulted with highly folded, thick biofilm with high cellular growth and iturin A production compared to the original no.3 medium.

  5. Enzymatic resistance to the lipopeptide surfactin as identified through imaging mass spectrometry of bacterial competition

    PubMed Central

    Hoefler, B. Christopher; Gorzelnik, Karl V.; Yang, Jane Y.; Hendricks, Nathan; Dorrestein, Pieter C.; Straight, Paul D.

    2012-01-01

    Many species of bacteria secrete natural products that inhibit the growth or development of competing species. In turn, competitors may develop or acquire resistance to antagonistic molecules. Few studies have investigated the interplay of these countervailing forces in direct competition between two species. We have used an imaging mass spectrometry (IMS) approach to track metabolites exchanged between Bacillus subtilis and Streptomyces sp. Mg1 cultured together. Surfactin is a cyclic lipopeptide produced by B. subtilis that inhibits the formation of aerial hyphae by streptomycetes. IMS analysis exposed an addition of 18 mass units to surfactin in the agar proximal to Streptomyces sp. Mg1 but not other streptomycetes tested. The spatially resolved change in the mass of surfactin indicated hydrolysis of the molecule. We observed that the aerial growth of Streptomyces sp. Mg1 was resistant to inhibition by surfactin, which suggests that hydrolysis was a mechanism of resistance. To identify possible enzymes from Streptomyces sp. Mg1 with surfactin hydrolase activity, we isolated secreted proteins and identified candidates by mass spectrometry. We purified one candidate enzyme that hydrolyzed surfactin in vitro. We tested the role of this enzyme in surfactin resistance by deleting the corresponding gene from the S. Mg1 genome. We observed that aerial growth by the ΔsfhA mutant strain was now sensitive to surfactin. Our results identify an enzyme that hydrolyzes surfactin and confers resistance to aerial growth inhibition, which demonstrates the effective use of an IMS approach to track natural product modifications during interspecies competition. PMID:22826229

  6. Inducible gene expression systems and plant biotechnology.

    PubMed

    Corrado, Giandomenico; Karali, Marianthi

    2009-01-01

    Plant biotechnology relies heavily on the genetic manipulation of crops. Almost invariantly, the gene of interest is expressed in a constitutive fashion, although this may not be strictly necessary for several applications. Currently, there are several regulatable expression systems for the temporal, spatial and quantitative control of transgene activity. These molecular switches are based on components derived from different organisms, which range from viruses to higher eukaryotes. Many inducible systems have been designed for fundamental and applied research and since their initial development, they have become increasingly popular in plant molecular biology. This review covers a broad number of inducible expression systems examining their properties and relevance for plant biotechnology in its various guises, from molecular breeding to pharmaceutical and industrial applications. For each system, we examine some advantages and limitations, also in relation to the strategy on which they rely. Besides being necessary to control useful genes that may negatively affect crop yield and quality, we discuss that inducible systems can be also used to increase public acceptance of GMOs, reducing some of the most common concerns. Finally, we suggest some directions and future developments for their further diffusion in agriculture and biotechnology.

  7. Induced systemic resistance by beneficial microbes.

    PubMed

    Pieterse, Corné M J; Zamioudis, Christos; Berendsen, Roeland L; Weller, David M; Van Wees, Saskia C M; Bakker, Peter A H M

    2014-01-01

    Beneficial microbes in the microbiome of plant roots improve plant health. Induced systemic resistance (ISR) emerged as an important mechanism by which selected plant growth-promoting bacteria and fungi in the rhizosphere prime the whole plant body for enhanced defense against a broad range of pathogens and insect herbivores. A wide variety of root-associated mutualists, including Pseudomonas, Bacillus, Trichoderma, and mycorrhiza species sensitize the plant immune system for enhanced defense without directly activating costly defenses. This review focuses on molecular processes at the interface between plant roots and ISR-eliciting mutualists, and on the progress in our understanding of ISR signaling and systemic defense priming. The central role of the root-specific transcription factor MYB72 in the onset of ISR and the role of phytohormones and defense regulatory proteins in the expression of ISR in aboveground plant parts are highlighted. Finally, the ecological function of ISR-inducing microbes in the root microbiome is discussed.

  8. Effect of different Bacillus subtilis lipopeptides on surface hydrophobicity and adhesion of Bacillus cereus 98/4 spores to stainless steel and Teflon.

    PubMed

    Shakerifard, Parvin; Gancel, Frédérique; Jacques, Philippe; Faille, Christine

    2009-01-01

    Various lipopeptides produced by Bacillus subtilis were examined for their ability to modify the surface hydrophobicity of two substrata, stainless steel (SS) and Teflon. These modifications were evaluated by water contact angle measurements. The effects depended on the lipopeptide, its concentration, and the tested substratum. Treatment of SS with different concentrations of surfactin S1 showed an increase of the hydrophobicity between 1 and 100 mg l(-1). On the same substratum, fengycin increased hydrophobicity up to its critical micelle concentration (6.25 mg l(-1)). With higher concentrations of fengycin, hydrophobicity decreased. Surfactin, mycosubtilin, and iturin A decreased hydrophobicity on Teflon. The different effects of these three families of lipopeptides were related to their structural differences. A good correlation was shown between hydrophobicity modifications of surfaces and the attachment of B. cereus 98/4 spores. Enhancement in the hydrophobicity of the surfaces increased the number of adhering spores.

  9. Different Arms of the Adaptive Immune System Induced by a Combination Vaccine Work in Concert to Provide Enhanced Clearance of Influenza

    PubMed Central

    Cobbin, Joanna C. A.; Zeng, Weiguang; Jackson, David C.; Brown, Lorena E.

    2014-01-01

    Current split influenza virus vaccines that induce strain-specific neutralising antibodies provide some degree of protection against influenza infection but there is a clear need to improve their effectiveness. The constant antigenic drift of influenza viruses means that vaccines are often not an exact match to the circulating strain and so levels of relevant antibodies may not be sufficiently high to afford protection. In the situation where the emergent influenza virus is completely novel, as is the case with pandemic strains, existing vaccines may provide no benefit. In this study we tested the concept of a combination vaccine consisting of sub-optimal doses of split influenza virus vaccine mixed with a cross-protective T-cell inducing lipopeptide containing the TLR2 ligand Pam2Cys. Mice immunised with combination vaccines showed superior levels of lung viral clearance after challenge compared to either split virus or lipopeptide alone, mediated through activation of enhanced humoral and/or additional cellular responses. The mechanism of action of these vaccines was dependent on the route of administration, with intranasal administration being superior to subcutaneous and intramuscular routes, potentially through the induction of memory CD8+ T cells in the lungs. This immunisation strategy not only provides a mechanism for minimising the dose of split virus antigen but also, through the induction of cross-protective CD8+ T cells, proves a breadth of immunity to provide potential benefit upon encounter with serologically diverse influenza isolates. PMID:25522323

  10. Identification of S-(2,3-dihydroxypropyl)cystein in a macrophage-activating lipopeptide from Mycoplasma fermentans.

    PubMed

    Mühlradt, P F; Meyer, H; Jansen, R

    1996-06-18

    Mycoplasmas are capable of stimulating monocytes and macrophages to release cytokines, prostaglandins, and nitric oxide. The aim of this study was to characterize the chemical nature of the previously isolated [Mühlradt, P. F., & Frisch, M. (1994) Infect. Immun. 62, 3801-3807] macrophage-stimulating material "MDHM" from Mycoplasma fermentans. Mycoplasmas were delipidated, and MDHM activity was extracted with octyl glucoside and further purified by reversed-phase HPLC. Macrophage-stimulating activity was monitored by nitric oxide release from peritoneal macrophages from C3H/HeJ endotoxin low responder mice. HPLC-purified MDHM was rechromatographed on an analytic scale RP 18 column before and after proteinase K treatment. Proteinase treatment did not diminish biological activity but shifted MDHM elution toward higher lipophilicity, suggesting that the macrophage-stimulating activity might reside in the lipopeptide moiety of a lipoprotein. Proteinase K-treated MDHM was hydrolyzed, amino groups were dansylated, and the dansylated material was isolated by HPLC. Dansylated S-(2,3-dihydroxypropyl)cystein (glycerylcystein thioether), typical for Braun's murein lipoprotein, and Dns-Gly and Dns-Thr were identified by tandem mass spectrometry. These amino acids were isolated from biologically active but not from the neighboring inactive HPLC fractions. IR spectra from proteinase K-treated, HPLC-purified MDHM and those from the synthetic lipopeptide [2,3-bis(palmitoyloxy)-(2-RS)-propyl]-N-palmitoyl-(R)-CysSerSer AsnAla were very similar. The data, taken together, indicate that lipoproteins of a nature previously detected in eubacteria are expressed in M. fermentans and that at least one of these lipoproteins and a lipopeptide derived from it constitute the macrophage-activating principle MDHM from these mycoplasmas.

  11. Tauramamide, a lipopeptide antibiotic produced in culture by Brevibacillus laterosporus isolated from a marine habitat: structure elucidation and synthesis.

    PubMed

    Desjardine, Kelsey; Pereira, Alban; Wright, Helen; Matainaho, Teatulohi; Kelly, Michael; Andersen, Raymond J

    2007-12-01

    Tauramamide (1), a new lipopeptide antibiotic, is produced by cultures of the marine bacterial isolate Brevibacillus laterosporus PNG276 obtained from Papua New Guinea. Tauramamide was isolated as its methyl and ethyl esters 2 and 3, whose structures were elucidated by analysis of NMR, MS, and chemical degradation data. A total synthesis of tauramamide (1) and tauramamide ethyl ester (3) confirmed the structure proposed from spectroscopic analysis and provided the natural product for antimicrobial testing. Tauramamide (1) and ethyl ester 3 show potent and relatively selective inhibition of pathogenic Enterococcus sp.

  12. Bacillus spp. Isolated from Puba as a Source of Biosurfactants and Antimicrobial Lipopeptides

    PubMed Central

    Perez, Karla J.; Viana, Jaime dos Santos; Lopes, Fernanda C.; Pereira, Jamile Q.; dos Santos, Daniel M.; Oliveira, Jamil S.; Velho, Renata V.; Crispim, Silvia M.; Nicoli, Jacques R.; Brandelli, Adriano; Nardi, Regina M. D.

    2017-01-01

    Several products of industrial interest are produced by Bacillus, including enzymes, antibiotics, amino acids, insecticides, biosurfactants and bacteriocins. This study aimed to investigate the potential of two bacterial isolates (P5 and C3) from puba, a regional fermentation product from cassava, to produce multiple substances with antimicrobial and surface active properties. Phylogenetic analyses showed close relation of isolates P5 and C3 with Bacillus amyloliquefaciens and Bacillus thuringiensis, respectively. Notably, Bacillus sp. P5 showed antimicrobial activity against pathogens such as Listeria monocytogenes and Bacillus cereus, in addition to antifungal activity. The presence of genes encoding pre-subtilosin (sboA), malonyl CoA transacylase (ituD), and the putative transcriptional terminator of surfactin (sfp) were detected in Bacillus sp. P5, suggesting the production of the bacteriocin subtilosin A and the lipopeptides iturin A and surfactin by this strain. For Bacillus sp. C3 the presence of sboA and spas (subtilin) genes was observed by the first time in members of B. cereus cluster. Bacillus sp. P5 showed emulsifying capability on mineral oil, soybean biodiesel and toluene, while Bacillus sp. C3 showed emulsifying capability only on mineral oil. The reduction of the surface tension in culture medium was also observed for strain P5, confirming the production of surface-active compounds by this bacterium. Monoprotonated molecular species and adducts of sodium and potassium ions of surfactin, iturin, and fengycin were detected in the P5 culture medium. Comparative MS/MS spectra of the peak m/z 1030 (C14 surfactin A or C15 surfactin B [M+Na]+) and peak m/z 1079 (C15 iturin [M+Na]+) showed the same fragmentation profile of standards, confirming the molecular identification. In conclusion, Bacillus sp. P5 showed the best potential for the production of antifungal, antibacterial, and biosurfactant substances. PMID:28197131

  13. Bacillus spp. Isolated from Puba as a Source of Biosurfactants and Antimicrobial Lipopeptides.

    PubMed

    Perez, Karla J; Viana, Jaime Dos Santos; Lopes, Fernanda C; Pereira, Jamile Q; Dos Santos, Daniel M; Oliveira, Jamil S; Velho, Renata V; Crispim, Silvia M; Nicoli, Jacques R; Brandelli, Adriano; Nardi, Regina M D

    2017-01-01

    Several products of industrial interest are produced by Bacillus, including enzymes, antibiotics, amino acids, insecticides, biosurfactants and bacteriocins. This study aimed to investigate the potential of two bacterial isolates (P5 and C3) from puba, a regional fermentation product from cassava, to produce multiple substances with antimicrobial and surface active properties. Phylogenetic analyses showed close relation of isolates P5 and C3 with Bacillus amyloliquefaciens and Bacillus thuringiensis, respectively. Notably, Bacillus sp. P5 showed antimicrobial activity against pathogens such as Listeria monocytogenes and Bacillus cereus, in addition to antifungal activity. The presence of genes encoding pre-subtilosin (sboA), malonyl CoA transacylase (ituD), and the putative transcriptional terminator of surfactin (sfp) were detected in Bacillus sp. P5, suggesting the production of the bacteriocin subtilosin A and the lipopeptides iturin A and surfactin by this strain. For Bacillus sp. C3 the presence of sboA and spas (subtilin) genes was observed by the first time in members of B. cereus cluster. Bacillus sp. P5 showed emulsifying capability on mineral oil, soybean biodiesel and toluene, while Bacillus sp. C3 showed emulsifying capability only on mineral oil. The reduction of the surface tension in culture medium was also observed for strain P5, confirming the production of surface-active compounds by this bacterium. Monoprotonated molecular species and adducts of sodium and potassium ions of surfactin, iturin, and fengycin were detected in the P5 culture medium. Comparative MS/MS spectra of the peak m/z 1030 (C14 surfactin A or C15 surfactin B [M+Na](+)) and peak m/z 1079 (C15 iturin [M+Na](+)) showed the same fragmentation profile of standards, confirming the molecular identification. In conclusion, Bacillus sp. P5 showed the best potential for the production of antifungal, antibacterial, and biosurfactant substances.

  14. Isolation and partial characterization of cyclic lipopeptide antibiotics produced by Paenibacillus ehimensis B7

    PubMed Central

    2013-01-01

    Background The prevalence of drug-resistant bacteria has encouraged the search for novel antimicrobial compounds. Food-associated microorganisms, as a source of new antibiotics, have recently received considerable attention. The objective of this study was to find novel antimicrobial agents produced by food microorganisms. Results A bacterial strain B7, which has potent antimicrobial activity, was isolated from a sample of dairy waste. This strain was identified as Paenibacillus ehimensis based on the 16S rRNA gene sequence analysis, physiological and biochemical characterization. Two active compounds (PE1 and PE2) were obtained from P. ehimensis B7. Mass spectrometry (MS) analysis showed that the molecular masses of PE1 and PE2 were 1,114 and 1,100 Da, respectively. The tandem MS and amino acid analysis indicated that PE1 and PE2 were analogs of polypeptin, and PE2 was characterized as a new member of this family. Both compounds were active against all tested bacterial pathogens, including methicillin resistant Staphylococcus aureus, Escherichia coli, and pan-drug resistant Pseudomonas aeruginosa clinical isolate. Time-kill assays demonstrated that at 4 × MIC (minimum inhibitory concentration), PE1 and PE2 rapidly reduced the number of viable cells by at least 3-orders of magnitude, indicating that they were bactericidal antibiotics. Conclusions In the present work, two cationic lipopeptide antibiotics (PE1 and PE2) were isolated from P. ehimensis B7 and characterized. These two peptides showed broad antimicrobial activity against all tested human pathogens and are worthy of further study. PMID:23594351

  15. Biochemical, Genetic, and Zoosporicidal Properties of Cyclic Lipopeptide Surfactants Produced by Pseudomonas fluorescens

    PubMed Central

    de Souza, Jorge T.; de Boer, Marjan; de Waard, Pieter; van Beek, Teris A.; Raaijmakers, Jos M.

    2003-01-01

    Zoospores play an important role in the infection of plant and animal hosts by oomycetes and other zoosporic fungi. In this study, six fluorescent Pseudomonas isolates with zoosporicidal activities were obtained from the wheat rhizosphere. Zoospores of multiple oomycetes, including Pythium species, Albugo candida, and Phytophthora infestans, were rendered immotile within 30 s of exposure to cell suspensions or cell culture supernatants of the six isolates, and subsequent lysis occurred within 60 s. The representative strain SS101, identified as Pseudomonas fluorescens biovar II, reduced the surface tension of water from 73 to 30 mN m−1. The application of cell suspensions of strain SS101 to soil or hyacinth bulbs provided significant protection against root rot caused by Pythium intermedium. Five Tn5 mutants of strain SS101lacked the abilities to reduce the surface tension of water and to cause lysis of zoospores. Genetic characterization of two surfactant-deficient mutants showed that the transposons had integrated into condensation domains of peptide synthetases. A partially purified extract from strain SS101 reduced the surface tension of water to 30 mN m−1 and reached the critical micelle concentration at 25 μg ml−1. Reverse-phase high-performance liquid chromatography yielded eight different fractions, five of which had surface activity and caused lysis of zoospores. Mass spectrometry and nuclear magnetic resonance analyses allowed the identification of the main constituent as a cyclic lipopeptide (1,139 Da) containing nine amino acids and a 10-carbon hydroxy fatty acid. The other four zoosporicidal fractions were closely related to the main constituent, with molecular massesranging from 1,111 to 1,169 Da. PMID:14660362

  16. Biochemical, genetic, and zoosporicidal properties of cyclic lipopeptide surfactants produced by Pseudomonas fluorescens.

    PubMed

    De Souza, Jorge T; De Boer, Marjan; De Waard, Pieter; Van Beek, Teris A; Raaijmakers, Jos M

    2003-12-01

    Zoospores play an important role in the infection of plant and animal hosts by oomycetes and other zoosporic fungi. In this study, six fluorescent Pseudomonas isolates with zoosporicidal activities were obtained from the wheat rhizosphere. Zoospores of multiple oomycetes, including Pythium species, Albugo candida, and Phytophthora infestans, were rendered immotile within 30 s of exposure to cell suspensions or cell culture supernatants of the six isolates, and subsequent lysis occurred within 60 s. The representative strain SS101, identified as Pseudomonas fluorescens biovar II, reduced the surface tension of water from 73 to 30 mN m-1. The application of cell suspensions of strain SS101 to soil or hyacinth bulbs provided significant protection against root rot caused by Pythium intermedium. Five Tn5 mutants of strain SS101lacked the abilities to reduce the surface tension of water and to cause lysis of zoospores. Genetic characterization of two surfactant-deficient mutants showed that the transposons had integrated into condensation domains of peptide synthetases. A partially purified extract from strain SS101 reduced the surface tension of water to 30 mN m-1 and reached the critical micelle concentration at 25 micrograms ml-1. Reverse-phase high-performance liquid chromatography yielded eight different fractions, five of which had surface activity and caused lysis of zoospores. Mass spectrometry and nuclear magnetic resonance analyses allowed the identification of the main constituent as a cyclic lipopeptide (1,139 Da) containing nine amino acids and a 10-carbon hydroxy fatty acid. The other four zoosporicidal fractions were closely related to the main constituent, with molecular massesranging from 1,111 to 1,169 Da.

  17. Induced seismicity associated with enhanced geothermal system

    SciTech Connect

    Majer, Ernest; Majer, Ernest L.; Baria, Roy; Stark, Mitch; Oates, Stephen; Bommer, Julian; Smith, Bill; Asanuma, Hiroshi

    2006-09-26

    Enhanced Geothermal Systems (EGS) offer the potential to significantly add to the world energy inventory. As with any development of new technology, some aspects of the technology has been accepted by the general public, but some have not yet been accepted and await further clarification before such acceptance is possible. One of the issues associated with EGS is the role of microseismicity during the creation of the underground reservoir and the subsequent extraction of the energy. The primary objectives of this white paper are to present an up-to-date review of the state of knowledge about induced seismicity during the creation and operation of enhanced geothermal systems, and to point out the gaps in knowledge that if addressed will allow an improved understanding of the mechanisms generating the events as well as serve as a basis to develop successful protocols for monitoring and addressing community issues associated with such induced seismicity. The information was collected though literature searches as well as convening three workshops to gather information from a wide audience. Although microseismicity has been associated with the development of production and injection operations in a variety of geothermal regions, there have been no or few adverse physical effects on the operations or on surrounding communities. Still, there is public concern over the possible amount and magnitude of the seismicity associated with current and future EGS operations. It is pointed out that microseismicity has been successfully dealt with in a variety of non-geothermal as well as geothermal environments. Several case histories are also presented to illustrate a variety of technical and public acceptance issues. It is concluded that EGS Induced seismicity need not pose any threat to the development of geothermal resources if community issues are properly handled. In fact, induced seismicity provides benefits because it can be used as a monitoring tool to understand the

  18. Systemic immunotoxicity reactions induced by adjuvanted vaccines.

    PubMed

    Batista-Duharte, Alexander; Portuondo, Deivys; Pérez, O; Carlos, Iracilda Zeppone

    2014-05-01

    Vaccine safety is a topic of concern for the treated individual, the family, the health care personnel, and the others involved in vaccination programs as recipients or providers. Adjuvants are necessary components to warrant the efficacy of vaccines, however the overstimulation of the immune system is also associated with adverse effects. Local reactions are the most frequent manifestation of toxicity induced by adjuvanted vaccines and, with the exception of the acute phase response (APR), much less is known about the systemic reactions that follow vaccination. Their low frequency or subclinical expression meant that this matter has been neglected. In this review, various systemic reactions associated with immune stimulation will be addressed, including: APR, hypersensitivity, induction or worsening of autoimmune diseases, modification of hepatic metabolism and vascular leak syndrome (VLS), with an emphasis on the mechanism involved. Finally, the authors analyze the current focus of discussion about vaccine safety and opportunities to improve the design of new adjuvanted vaccines in the future.

  19. Inducing Systems Thinking in Consumer Societies

    NASA Astrophysics Data System (ADS)

    Minati, Gianfranco; Magliocca, Larry A.

    We introduce some core principles related to systems thinking: interaction, establishment of systems through organization and self-organization (emergence), and the constructivist role of the observer including the use of language. It is not effective to deal with systemic properties in a non-systemic way, by adopting a reductionist way of thinking, i.e., when properties acquired by systems are considered as properties possessed by objects. We consider the reduced language adopted in consumer societies as functional to maintain consumerist attitude. In consumer societies, language is suitable for maintaining people in the role of consumers with a limited ability to design and create. In this context freedom is intended as freedom of choice. To counteract this reduced language, we propose the diffusion of suitable games, cartoons, comics and pictures, images, concepts and words which can enrich everyday language, especially that of young people, and provide an effective way for inducing some elementary aspects of systems thinking in everyday life. The purpose is to have a language to design and develop things and not merely to select from what is already available. We list a number of proposals for the design of such games, stories and pictures.

  20. Characterization of antimicrobial lipopeptides produced by Bacillus sp. LM7 isolated from chungkookjang, a Korean traditional fermented soybean food.

    PubMed

    Lee, Mi-Hwa; Lee, Jiyeon; Nam, Young-Do; Lee, Jong Suk; Seo, Myung-Ji; Yi, Sung-Hun

    2016-03-16

    A wild-type microorganism exhibiting antimicrobial activities was isolated from the Korean traditional fermented soybean food Chungkookjang and identified as Bacillus sp. LM7. During its stationary growth phase, the microorganism secreted an antimicrobial substance, which we partially purified using a simple two-step procedure involving ammonium sulfate precipitation and heat treatment. The partially purified antimicrobial substance, Anti-LM7, was stable over a broad pH range (4.0-9.0) and at temperatures up to 80 °C for 30 min, and was resistant to most proteolytic enzymes and maintained its activity in 30% (v/v) organic solvents. Anti-LM7 inhibited the growth of a broad range of Gram-positive bacteria, including Bacillus cereus and Listeria monocytogenes, but it did not inhibit lactic acid bacteria such as Lactobacillus plantarum and Lactococcus lactis subsp. Lactis. Moreover, unlike commercially available nisin and polymyxin B, Anti-LM7 inhibited certain fungal strains. Lastly, liquid chromatography-mass spectrometry analysis of Anti-LM7 revealed that it contained eight lipopeptides belonging to two families: four bacillomycin D and four surfactin analogs. These Bacillus sp. LM7-produced heterogeneous lipopeptides exhibiting extremely high stability and a broad antimicrobial spectrum are likely to be closely related to the antimicrobial activity of Chungkookjang, and their identification presents an opportunity for application of the peptides in environmental bioremediation, pharmaceutical, cosmetic, and food industries.

  1. Self-assembly and interactions of short antimicrobial cationic lipopeptides with membrane lipids: ITC, FTIR and molecular dynamics studies.

    PubMed

    Sikorska, Emilia; Dawgul, Małgorzata; Greber, Katarzyna; Iłowska, Emilia; Pogorzelska, Aneta; Kamysz, Wojciech

    2014-10-01

    In this work, the self-organization and the behavior of the surfactant-like peptides in the presence of biological membrane models were studied. The studies were focused on synthetic palmitic acid-containing lipopeptides, C16-KK-NH2 (I), C16-KGK-NH2 (II) and C16-KKKK-NH2 (III). The self-assembly was explored by molecular dynamics simulations using a coarse-grained force field. The critical micellar concentration was estimated by the surface tension measurements. The thermodynamics of the peptides binding to the anionic and zwitterionic lipids were established using isothermal titration calorimetry (ITC). The influence of the peptides on the lipid acyl chain ordering was determined using FTIR spectroscopy. The compounds studied show surface-active properties with a distinct CMC over the millimolar range. An increase in the steric and electrostatic repulsion between polar head groups shifts the CMC toward higher values and reduces the aggregation number. An analysis of the peptide-membrane binding revealed a unique interplay between the initial electrostatic and the subsequent hydrophobic interactions enabling the lipopeptides to interact with the lipid bilayer. In the case of C16-KKKK-NH2 (III), compensation of the electrostatic and hydrophobic interactions upon binding to the anionic membrane has been suggested and consequently no overall binding effects were noticed in ITC thermograms and FTIR spectra.

  2. Key Impact of an Uncommon Plasmid on Bacillus amyloliquefaciens subsp. plantarum S499 Developmental Traits and Lipopeptide Production

    PubMed Central

    Molinatto, Giulia; Franzil, Laurent; Steels, Sébastien; Puopolo, Gerardo; Pertot, Ilaria; Ongena, Marc

    2017-01-01

    The rhizobacterium Bacillus amyloliquefaciens subsp. plantarum S499 (S499) is particularly efficient in terms of the production of cyclic lipopeptides, which are responsible for the high level of plant disease protection provided by this strain. Sequencing of the S499 genome has highlighted genetic differences and similarities with the closely related rhizobacterium B. amyloliquefaciens subsp. plantarum FZB42 (FZB42). More specifically, a rare 8008 bp plasmid (pS499) harboring a rap-phr cassette constitutes a major distinctive element between S499 and FZB42. By curing this plasmid, we demonstrated that its presence is crucial for preserving the typical physiology of S499 cells. Indeed, the growth rate and extracellular proteolytic activity were significantly affected in the cured strain (S499 P−). Furthermore, pS499 made a significant contribution to the regulation of cyclic lipopeptide production. Surfactins and fengycins were produced in higher quantities by S499 P−, whereas lower amounts of iturins were detected. In line with the increase in surfactin release, bacterial motility improved after curing, whereas the ability to form biofilm was reduced in vitro. The antagonistic effect against phytopathogenic fungi was also limited for S499 P−, most probably due to the reduction of iturin production. With the exception of this last aspect, S499 P− behavior fell between that of S499 and FZB42, suggesting a role for the plasmid in shaping some of the phenotypic differences observed in the two strains. PMID:28154555

  3. Antifungal Lipopeptides Produced by Bacillus sp. FJAT-14262 Isolated from Rhizosphere Soil of the Medicinal Plant Anoectochilus roxburghii.

    PubMed

    Chen, Qianqian; Liu, Bo; Wang, Jieping; Che, Jianmei; Liu, Guohong; Guan, Xiong

    2016-11-16

    This study aimed to develop biocontrol Bacillus and explore bacterial biocontrol substances. According to the blood agar test, strain FJAT-14262 was screened as a biosurfactant-producer. The biosurfactant-producing ability of FJAT-14262 was further confirmed by the oil spreading tests because of its amphipathic character. Furthermore, its fermentation supernatant could decrease the surface tension from 74.1 to 32.7 mN m(-1). Fourier transform infrared spectroscopy (FT-IR) analysis indicated that the biosurfactant produced by the strain FJAT-14262 was a kind of lipopeptides. Reverse-phase high-performance liquid chromatography (RP-HPLC) and liquid chromatography-mass spectrometry (LC-MS) analysis demonstrated that this lipopeptide contained surfactin with polar amino acids and hydrophobic fatty acid chains. Moreover, bioinformatic analysis revealed that the nonribosomal peptide synthetases genes srfAA, srfAB, and srfAC were structurally conserved in the FJAT-14262 genome. Importantly, the crude surfactant exhibited strong inhibitory activities against Fusarium oxysporum, suggesting that strain FJAT-14262 could be a potential biological control agent against Fusarium wilt.

  4. First report of a lipopeptide biosurfactant from thermophilic bacterium Aneurinibacillus thermoaerophilus MK01 newly isolated from municipal landfill site.

    PubMed

    Sharafi, Hakimeh; Abdoli, Mahya; Hajfarajollah, Hamidreza; Samie, Nima; Alidoust, Leila; Abbasi, Habib; Fooladi, Jamshid; Zahiri, Hossein Shahbani; Noghabi, Kambiz Akbari

    2014-07-01

    A biosurfactant-producing thermophile was isolated from the Kahrizak landfill of Tehran and identified as a bacterium belonging to the genus Aneurinibacillus. A thermostable lipopeptide-type biosurfactant was purified from the culture medium of this bacterium and showed stability in the temperature range of 20-90 °C and pH range of 5-10. The produced biosurfactant could reduce the surface tension of water from 72 to 43 mN/m with a CMC of 1.21 mg/mL. The strain growing at a temperature of 45 °C produces a substantial amount of 5 g/L of biosurfactant in the medium supplemented with sunflower oil as the sole carbon source. Response surface methodology was employed to optimize the biosurfactant production using sunflower oil, sodium nitrate, and yeast extract as variables. The optimization resulted in 6.75 g/L biosurfactant production, i.e., 35% improved as compared to the unoptimized condition. Thin-layer chromatography, FTIR spectroscopy, 1H-NMR spectroscopy, and biochemical composition analysis confirmed the lipopeptide structure of the biosurfactant.

  5. Lipopeptides, a novel protein, and volatile compounds contribute to the antifungal activity of the biocontrol agent Bacillus atrophaeus CAB-1.

    PubMed

    Zhang, Xiaoyun; Li, Baoqing; Wang, Ye; Guo, Qinggang; Lu, Xiuyun; Li, Shezeng; Ma, Ping

    2013-11-01

    Bacillus atrophaeus CAB-1 displays a high inhibitory activity against various fungal pathogens and suppresses cucumber powdery mildew and tomato gray mold. We extracted and identified lipopeptides and secreted proteins and volatile compounds produced by strain CAB-1 to investigate the mechanisms involved in its biocontrol performance. In vitro assays indicated all three types of products contributed to the antagonistic activity against the fungal pathogen Botrytis cinerea. Each of these components also effectively prevented the occurrence of the cucumber powdery mildew caused by Sphaerotheca fuliginea under greenhouse conditions. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry revealed that the major bioactive lipopeptide was fengycin A (C15-C17). We isolated the crude-secreted proteins of CAB-1 and purified a fraction with antifungal activity. This protein sequence shared a high identity with a putative phage-related pre-neck appendage protein, which has not been reported as an antifungal factor. The volatile compounds produced by CAB-1 were complex, including a range of alcohols, phenols, amines, and alkane amides. O-anisaldehyde represented one of the most abundant volatiles with the highest inhibition on the mycelial growth of B. cinerea. To our knowledge, this is the first report on profiling three types of antifungal substances in Bacilli and demonstrating their contributions to plant disease control.

  6. Brevibacillin, a cationic lipopeptide that binds to lipoteichoic acid and subsequently disrupts cytoplasmic membrane of Staphylococcus aureus.

    PubMed

    Yang, Xu; Huang, En; Yousef, Ahmed E

    2017-01-01

    Brevibacillin is a newly-discovered antimicrobial lipopeptide produced by Brevibacillus laterosporus OSY-I1. It is active against Gram-positive bacteria, including antibiotic resistant strains. This research was initiated to investigate the mechanism of action of brevibacillin against an indicator strain, Staphylococcus aureus ATCC 6538. Results of the study proved that brevibacillin binds to lipoteichoic acid (LTA) on cell wall before interacting with cell membrane. Additionally, brevibacillin disrupts S. aureus cytoplasmic membrane by increasing its permeability, depolarization and potassium leakage. Therefore, cytoplasmic membrane serves as a major target for brevibacillin. Despite the presence of multiple sites on S. aureus cell envelope, scanning electron microscope observation didn't reveal evidence of cell lysis or any morphological defects in cells treated with brevibacillin. Based on the results of this study, we propose that the electrostatic interaction between the cationic brevibacillin and the anionic LTA helped the accumulation of the antimicrobial agent at cell surface; this was followed by translocation of the lipopeptide to the cytoplasmic membrane and disrupting its vital functions.

  7. Antimicrobial Activity and Toxicity of the Major Lipopeptide Components of Polymyxin B and Colistin: Last-line Antibiotics against Multidrug-Resistant Gram-negative Bacteria

    PubMed Central

    Roberts, Kade D.; Azad, Mohammad A. K.; Wang, Jiping; Horne, Andrew S; Thompson, Philip E.; Nation, Roger L.; Velkov, Tony; Li, Jian

    2016-01-01

    Polymyxin B and colistin are currently used as a ‘last-line’ treatment for multidrug-resistant Gram-negative bacteria. However very little is known about the pharmacological differences between polymyxin B1, polymyxin B2, colistin A, colistin B, the major cyclic lipopeptides components present in polymyxin B and colistin products. Here, we report on the in vitro and in vivo antimicrobial activity and toxicity of these major lipopeptide components. All four lipopeptides had comparable MICs (<0.125–4 mg/L) against a panel of clinical Gram-negative isolates. They also had comparable in vivo antimicrobial activity (Δlog10 CFU/mL >-3) and nephrotoxicity (mild to moderate histological damage) in mouse models. However, polymyxin B1 and colistin A showed significantly higher (> 3-fold) in vitro apoptotic effect on human kidney proximal tubular HK-2 cells than polymyxin B2 and colistin B, respectively. Compared to the commercial polymyxin and colistin products, the individual lipopeptide components had slightly more in vivo antimicrobial activity. Our results highlight the need to re-assess pharmacopoeial standards for polymyxins B and colistin and to standardize the composition of the different commercial products of polymyxin antibiotics. PMID:27525307

  8. Use of capillary electrophoresis as a versatile tool to measure interaction constants between a KDR-binding PEGylated lipopeptide and pegylated phospholipid micelles.

    PubMed

    Poitevin, Martine; Tranquart, François; Cherkaoui, Samir

    2015-01-01

    In the frame of our molecular imaging activities, a PEGylated lipopeptide has been developed as a specific ligand for the human vascular endothelial growth factor receptor 2, which is considered as one of the important molecular marker of angiogenesis. In this study, the potential of affinity capillary electrophoresis (ACE) is evaluated to measure the interactions of an active PEGylated lipopeptide, its hydrolysis product and its precursor consisting of a peptide structure with different micelles including Brij-35, Tween-20, and pegylated phospholipids. Given the amphiphilic structure of the PEGylated lipopeptide, a MEKC method allowing the simultaneous separation of the compounds of interest was set up, using low percentages of acetonitrile. Analytes were resolved using a BGE consisting of 100 mM borate buffer pH 9.0, 1 mM Brij, and 25% acetonitrile. Optimized conditions were then used to perform ACE experiments. The affinity constants of the analytes with the micelles were calculated on the basis of their mobility decrease when surfactant concentration increased in the electrolyte. The use of different linearization models to estimate affinity constants was discussed and comparison of different surfactants was reported. PEGylated lipopeptide interacted more strongly with pegylated phospholipid micelles than with Brij-35 or Tween-20. Moreover, it is likely that the chemical structure of the compounds, and particularly the lipidic part of the molecules, significantly affects the interaction with micelles. In conclusion, the ACE method can be readily applied to investigate interactions of our targeting lipopeptides with various micelles currently used for the preparation of pharmaceutical vehicles.

  9. Effect of ester to amide or N-methylamide substitution on bacterial membrane depolarization and antibacterial activity of novel cyclic lipopeptides.

    PubMed

    Bionda, Nina; Fleeman, Renee M; Shaw, Lindsey N; Cudic, Predrag

    2013-08-01

    Cyclic lipopeptides derived from the fusaricidin/LI-F family of naturally occurring antibiotics represent particularly attractive candidates for the development of new antibacterial agents. In comparison with natural products, these derivatives may offer better stability under physiologically relevant conditions and lower nonspecific toxicity, while preserving their antibacterial activity. In this study we assessed the ability of cyclic lipodepsipeptide 1 and its analogues--amide 2, N-methylamide 3, and linear peptide 4--to interact with the cytoplasmic membranes of selected Gram-positive bacteria. We also investigated their bacteriostatic/bactericidal modes of action and in vivo potency by using a Galleria mellonella model of MRSA infection. Cyclic lipopeptides 1 and 2 depolarize the cytoplasmic membranes of Gram-positive bacteria in a concentration-dependent manner. The degree of membrane depolarization was influenced by the structural and physical properties of 1 and 2, with the more flexible and hydrophobic peptide 1 being most efficient. However, membrane depolarization does not correlate with bacterial cell lethality, suggesting that membrane-targeting activity is not the main mode of action for this class of antibacterial peptides. Conversely, substitution of the depsipeptide bond in 1 with an N-methylamide bond in 3, or its hydrolysis to peptide 4, lead to a complete loss of antibacterial activity and indicate that the conformation of cyclic lipopeptides plays a role in their antibacterial activities. Cyclic lipopeptides 1 and 2 are also capable of improving the survival of G. mellonella larvae infected with MRSA at varying efficiencies, reflecting their in vitro activities. Gaining more insight into the structure-activity relationship and mode of action of these cyclic lipopeptides may enable the development of new antibiotics of this class with improved antibacterial activity.

  10. Memory CD8(+) T cells elicited by HIV-1 lipopeptide vaccines display similar phenotypic profiles but differences in term of magnitude and multifunctionality compared with FLU- or EBV-specific memory T cells in humans.

    PubMed

    Figueiredo, Suzanne; Charmeteau, Benedicte; Surenaud, Mathieu; Salmon, Dominique; Launay, Odile; Guillet, Jean-Gérard; Hosmalin, Anne; Gahery, Hanne

    2014-01-16

    Differentiation marker, multifunctionality and magnitude analyses of specific-CD8(+) memory T cells are crucial to improve development of HIV vaccines designed to generate cell-mediated immunity. Therefore, we fully characterized the HIV-specific CD8(+) T cell responses induced in volunteers vaccinated with HIV lipopeptide vaccines for phenotypic markers, tetramer staining, cytokine secretion, and cytotoxic activities. The frequency of ex vivo CD8(+) T cells elicited by lipopeptide vaccines is very rare and central-memory phenotype and functions of these cells were been shown to be important in AIDS immunity. So, we expanded them using specific peptides to compare the memory T cell responses induced in volunteers by HIV vaccines with responses to influenza (FLU) or Epstein Barr virus (EBV). By analyzing the differentiation state of IFN-γ-secreting CD8(+) T cells, we found a CCR7(-)CD45RA(-)CD28(+int)/CD28(-) profile (>85%) belonging to a subset of intermediate-differentiated effector T cells for HIV, FLU, and EBV. We then assessed the quality of the response by measuring various T cell functions. The percentage of single IFN-γ T cell producers in response to HIV was 62% of the total of secreting T cells compared with 35% for FLU and EBV, dual and triple (IFN-γ/IL-2/CD107a) T cell producers could also be detected but at lower levels (8% compared with 37%). Finally, HIV-specific T cells secreted IFN-γ and TNF-α, but not the dual combination like FLU- and EBV-specific T cells. Thus, we found that the functional profile and magnitude of expanded HIV-specific CD8(+) T precursors were more limited than those of to FLU- and EBV-specific CD8(+) T cells. These data show that CD8(+) T cells induced by these HIV vaccines have a similar differentiation profile to FLU and EBV CD8(+) T cells, but that the vaccine potency to induce multifunctional T cells needs to be increased in order to improve vaccination strategies.

  11. Isolation and characterization of a lipopeptide bioemulsifier produced by Pseudomonas nitroreducens TSB.MJ10 isolated from a mangrove ecosystem.

    PubMed

    de Sousa, Trelita; Bhosle, Saroj

    2012-11-01

    Pseudomonas nitroreducens TSB.MJ10 exhibiting growth and bioemulsifier production with 0.5% sodium benzoate as the sole carbon source was isolated from a mangrove ecosystem in the vicinity of a petroleum pump. The bioemulsifier is a lipopeptide that is stable over a pH range of 5-11 and a temperature range of 20-90°C and showed emulsifying activity in the presence of relatively high NaCl concentrations (up to 25%). The bioemulsifier formed stable emulsions with aliphatic (hexadecane, n-heptane, cyclohexane), aromatic (xylene, benzene, toluene) and petroleum (gasoline, diesel, kerosene, crude oil) compounds. It exhibited a maximum emulsification activity with weathered crude oil (97%) and was capable of transforming the rheological behavior of the pseudoplastic to a Newtonian fluid. The results reveal the potential of the bioemulsifier for use in bioremediation of hydrocarbons in marine environments and in enhanced oil recovery.

  12. Biofilm inhibition and antimicrobial action of lipopeptide biosurfactant produced by heavy metal tolerant strain Bacillus cereus NK1.

    PubMed

    Sriram, Muthu Irulappan; Kalishwaralal, Kalimuthu; Deepak, Venkataraman; Gracerosepat, Raja; Srisakthi, Kandasamy; Gurunathan, Sangiliyandi

    2011-07-01

    Biosurfactants are worthful microbial amphiphilic molecules with efficient surface-active and biological properties applicable to several industries and processes. Among them lipopeptides represent a class of microbial surfactants with increasing scientific, therapeutic and biotechnological interests. A heavy metal tolerant Bacillus strain has been isolated and the biofilm inhibition and antimicrobial activity of biosurfactant produced by the strain have been studied. Biosurfactant production was confirmed by the conventional screening methods including hemolytic activity, drop collapsing test, oil displacement test, emulsification and lipase production assays. The biosurfactant produced by this strain was a lipopeptide and exhibited strong surface activity. The biosurfactant has been characterized using FTIR, TLC and HPLC. The minimum active dose of this biosurfactant when compared with the other chemical surfactants was found as 0.150±0.06 μg. The critical micelle concentration was found to be 45 mg/l. The biosurfactant was found to be stable and active over a wide range of pH, temperature and NaCl concentration. It was also able to emulsify a wide range of hydrocarbons and oils thereby extending its application for the bioremediation of oil contaminated sites. The biosurfactant exhibited significant reduction in biofilm formation by pathogens and showed potent antimicrobial activity against various gram positive, gram negative bacteria and fungi. Agar diffusion assay for heavy metal resistance showed that the isolate was resistant to ferrous, lead and zinc. Considering the biofilm inhibition and antimicrobial property of biosurfactant, it can be utilized as a potential therapeutic molecule for numerous microbial infections. The heavy metal resistance of the strain can also be harnessed as an invaluable biological tool for in situ bioremediation.

  13. Supramolecular gels from lipopeptide gelators: template improvement and strategies for the in-situ preparation of inorganic nanomaterials and for the dispersion of carbon nanomaterials.

    PubMed

    Delbecq, Frederic

    2014-07-01

    Lipopeptide amphiphiles are an important class of biobased and biomimetic surfactants that are easily prepared from the cheapest organic reagents, such as natural fatty and amino acids, and in many cases, the resulting compounds are able to harden not only common organic solvents but also waxes, water and ionic liquids. Well-tailored, these gelators can be selective for one variety of liquid, which leads to the formation of a robust gel that is able to incorporate various different elements. In this review, we attempted to provide our opinion regarding the molecular design of the lipopeptide gelator candidates. In addition, we summarized each type of element that is necessary for creating potent supramolecular gel templates that are useful for inorganic nano- and micro-material preparation. This review is not only limited to recent papers found in the literature; a portion of our unpublished results are also provided as a supplement to illustrate our point of view regarding this subject.

  14. Lipopeptide-based micellar and liposomal carriers: Influence of surface charge and particle size on cellular uptake into blood brain barrier cells.

    PubMed

    Sydow, Karl; Nikolenko, Heike; Lorenz, Dorothea; Müller, Rainer H; Dathe, Margitta

    2016-12-01

    Lipopeptide-based micelles and liposomes were found to differ in cell recognition and uptake mode into blood brain barrier (BBB) endothelial cells. Here we analyse the role of size and surface charge of micelles and liposomes composed of different lipopeptide sequences with respect to uptake into human brain capillary (HBMEC) and aortic (HAoEC) endothelial cells. Comparable to the dipalmitoylated apolipoprotein E-derived P2A2, lipopeptides of cationic poly-arginine (P2Rn), poly-lysine (P2Kn) and an anionic glutamic-acid sequence (P2En) self assemble into micelles (12-14nm in diameter) with high surface charge density, and bind to small (SUVs, about 24nm in diameter) and large (LUV, about 100nm in diameter) liposomes at variable lipid to peptide ratios. The interaction pattern of the resulting particles with endothelial cells is highly variable as revealed by confocal laser scanning microscopic (CLSM) and fluorescence assisted cell sorting (FACS) studies. Micelles and SUVs with high P2A2 density are efficiently and selectively internalized into HBMEC. P2Kn micelles strongly accumulate in both the cytosol and at the cell membrane, while the interaction of liposomes tagged with a low amount of P2A2 and P2Kn with the cells was reduced. Anionic micelles seem to dissociate in the presence of cells and P2En molecules incorporate into the cellular membrane whereas the negatively charged liposomes hardly interact with cells. Surprisingly, all poly-R-based particles show high selectivity for HBMEC compared to HAoEC, independent of particle size and peptide surface density. The P2Rn-mediated internalization is highly efficient and partially clathrin-dependent. The oligo-R lipopeptide is considered to be most promising to selectively transport different drug carriers into the blood brain barrier.

  15. Isolation and Structural Elucidation of Brevibacillin, an Antimicrobial Lipopeptide from Brevibacillus laterosporus That Combats Drug-Resistant Gram-Positive Bacteria

    PubMed Central

    Yang, Xu; Yuan, Chunhua; Zhang, Liwen

    2016-01-01

    A new environmental bacterial strain exhibited strong antimicrobial characteristics against methicillin-resistant Staphylococcus aureus, vancomycin-resistant strains of Enterococcus faecalis and Lactobacillus plantarum, and other Gram-positive bacteria. The producer strain, designated OSY-I1, was determined to be Brevibacillus laterosporus via morphological, biochemical, and genetic analyses. The antimicrobial agent was extracted from cells of OSY-I1 with isopropanol, purified by high-performance liquid chromatography, and structurally analyzed using mass spectrometry (MS) and nuclear magnetic resonance (NMR). The MS and NMR results, taken together, uncovered a linear lipopeptide consisting of 13 amino acids and an N-terminal C6 fatty acid (FA) chain, 2-hydroxy-3-methylpentanoic acid. The lipopeptide (FA-Dhb-Leu-Orn-Ile-Ile-Val-Lys-Val-Val-Lys-Tyr-Leu-valinol, where Dhb is α,β-didehydrobutyric acid and valinol is 2-amino-3-methyl-1-butanol) has a molecular mass of 1,583.0794 Da and contains three modified amino acid residues: α,β-didehydrobutyric acid, ornithine, and valinol. The compound, designated brevibacillin, was determined to be a member of a cationic lipopeptide antibiotic family. In addition to its potency against drug-resistant bacteria, brevibacillin also exhibited low MICs (1 to 8 μg/ml) against selected foodborne pathogenic and spoilage bacteria, such as Listeria monocytogenes, Bacillus cereus, and Alicyclobacillus acidoterrestris. Purified brevibacillin showed no sign of degradation when it was held at 80°C for 60 min, and it retained at least 50% of its antimicrobial activity when it was held for 22 h under acidic or alkaline conditions. On the basis of these findings, brevibacillin is a potent antimicrobial lipopeptide which is potentially useful to combat drug-resistant bacterial pathogens and foodborne pathogenic and spoilage bacteria. PMID:26921428

  16. Importance of the Long-Chain Fatty Acid Beta-Hydroxylating Cytochrome P450 Enzyme YbdT for Lipopeptide Biosynthesis in Bacillus subtilis Strain OKB105

    PubMed Central

    Youssef, Noha H.; Wofford, Neil; McInerney, Michael J.

    2011-01-01

    Bacillus species produce extracellular, surface-active lipopeptides such as surfactin that have wide applications in industry and medicine. The steps involved in the synthesis of 3-hydroxyacyl-coenzyme A (CoA) substrates needed for surfactin biosynthesis are not understood. Cell-free extracts of Bacillus subtilis strain OKB105 synthesized lipopeptide biosurfactants in presence of l-amino acids, myristic acid, coenzyme A, ATP, and H2O2, which suggested that 3-hydroxylation occurs prior to CoA ligation of the long chain fatty acids (LCFAs). We hypothesized that YbdT, a cytochrome P450 enzyme known to beta-hydroxylate LCFAs, functions to form 3-hydroxy fatty acids for lipopeptide biosynthesis. An in-frame mutation of ybdT was constructed and the resulting mutant strain (NHY1) produced predominantly non-hydroxylated lipopeptide with diminished biosurfactant and beta-hemolytic activities. Mass spectrometry showed that 95.6% of the fatty acids in the NHY1 biosurfactant were non-hydroxylated compared to only ∼61% in the OKB105 biosurfactant. Cell-free extracts of the NHY1 synthesized surfactin containing 3-hydroxymyristic acid from 3-hydroxymyristoyl-CoA at a specific activity similar to that of the wild type (17 ± 2 versus 17.4 ± 6 ng biosurfactant min−1·ng·protein−1, respectively). These results showed that the mutation did not affect any function needed to synthesize surfactin once the 3-hydroxyacyl-CoA substrate was formed and that YbdT functions to supply 3-hydroxy fatty acid for surfactin biosynthesis. The fact that YbdT is a peroxidase could explain why biosurfactant production is rarely observed in anaerobically grown Bacillus species. Manipulation of LCFA specificity of YbdT could provide a new route to produce biosurfactants with activities tailored to specific functions. PMID:21673922

  17. Isolation and Structural Elucidation of Brevibacillin, an Antimicrobial Lipopeptide from Brevibacillus laterosporus That Combats Drug-Resistant Gram-Positive Bacteria.

    PubMed

    Yang, Xu; Huang, En; Yuan, Chunhua; Zhang, Liwen; Yousef, Ahmed E

    2016-05-01

    A new environmental bacterial strain exhibited strong antimicrobial characteristics against methicillin-resistant Staphylococcus aureus, vancomycin-resistant strains of Enterococcus faecalis and Lactobacillus plantarum, and other Gram-positive bacteria. The producer strain, designated OSY-I1, was determined to be Brevibacillus laterosporusvia morphological, biochemical, and genetic analyses. The antimicrobial agent was extracted from cells of OSY-I1 with isopropanol, purified by high-performance liquid chromatography, and structurally analyzed using mass spectrometry (MS) and nuclear magnetic resonance (NMR). The MS and NMR results, taken together, uncovered a linear lipopeptide consisting of 13 amino acids and an N-terminal C6 fatty acid (FA) chain, 2-hydroxy-3-methylpentanoic acid. The lipopeptide (FA-Dhb-Leu-Orn-Ile-Ile-Val-Lys-Val-Val-Lys-Tyr-Leu-valinol, where Dhb is α,β-didehydrobutyric acid and valinol is 2-amino-3-methyl-1-butanol) has a molecular mass of 1,583.0794 Da and contains three modified amino acid residues: α,β-didehydrobutyric acid, ornithine, and valinol. The compound, designated brevibacillin, was determined to be a member of a cationic lipopeptide antibiotic family. In addition to its potency against drug-resistant bacteria, brevibacillin also exhibited low MICs (1 to 8 μg/ml) against selected foodborne pathogenic and spoilage bacteria, such as Listeria monocytogenes,Bacillus cereus, and Alicyclobacillus acidoterrestris Purified brevibacillin showed no sign of degradation when it was held at 80 °C for 60 min, and it retained at least 50% of its antimicrobial activity when it was held for 22 h under acidic or alkaline conditions. On the basis of these findings, brevibacillin is a potent antimicrobial lipopeptide which is potentially useful to combat drug-resistant bacterial pathogens and foodborne pathogenic and spoilage bacteria.

  18. Conformational analyses of bacillomycin D, a natural antimicrobial lipopeptide, alone or in interaction with lipid monolayers at the air-water interface.

    PubMed

    Nasir, Mehmet Nail; Besson, Françoise

    2012-12-01

    Bacillomycin D is a natural antimicrobial lipopeptide belonging to the iturin family. It is produced by Bacillus subtilis strains. Bacillomycin D is characterized by its strong antifungal and hemolytic properties, due to its interaction with the plasma membrane of sensitive cells. Until now, only few limited analyses were conducted to understand the biological activities of bacillomycin D at the molecular level. Our purpose was to analyze the conformation of bacillomycin D using IR spectroscopy and to model its interactions with cytoplasmic membranes using Langmuir interfacial monolayers. Our findings indicate that bacillomycin D contains turns and allow to model its three-dimensional structure. Bacillomycin D formed a monolayer film at the air-water interface and kept its turn conformation, as shown by polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS). To identify the membrane lipid target of bacillomycin D, its interactions with pure lipid monolayers were analyzed and an original behavior of the lipopeptide toward cholesterol-containing monolayers was shown. This original behavior was lost when bacillomycin D was interacting with pure cholesteryl acetate monolayers, suggesting the involvement of the alcohol group of cholesterol in the lipopeptide-cholesterol interaction.

  19. Self-Assembly of the Toll-Like Receptor Agonist Macrophage-Activating Lipopeptide MALP-2 and of Its Constituent Peptide.

    PubMed

    Castelletto, Valeria; Kirkham, Steven; Hamley, Ian W; Kowalczyk, Radoslaw; Rabe, Martin; Reza, Mehedi; Ruokolainen, Janne

    2016-02-08

    The self-assembly of the macrophage-activating lipopeptide MALP-2 in aqueous solution has been investigated and is compared to that of the constituent peptide GNNDESNISFKEK. MALP-2 is a toll-like receptor agonist lipopeptide with diverse potential biomedical applications and its self-assembly has not previously been examined. It is found to self-assemble, above a critical aggregation concentration (cac), into remarkable "fibre raft" structures, based on lateral aggregation of β-sheet based bilayer tapes. Peptide GNNDESNISFKEK also forms β-sheet structures above a cac, although the morphology is distinct, comprising highly extended and twisted tape structures. A detailed insight into the molecular packing within the MALP-2 raft and GNNDESNISFKEK nanotape structures is obtained through X-ray diffraction and small-angle X-ray scattering. These results point to the significant influence of the attached lipid chains on the self-assembly motif, which lead to the raft structure for the lipopeptide assemblies.

  20. The self-assembly of a cyclic lipopeptides mixture secreted by a B. megaterium strain and its implications on activity against a sensitive Bacillus species.

    PubMed

    Pueyo, Manuel T; Mutafci, Bruna A; Soto-Arriaza, Marco A; Di Mascio, Paolo; Carmona-Ribeiro, Ana M

    2014-01-01

    Cyclic lipopeptides are produced by a soil Bacillus megaterium strain and several other Bacillus species. In this work, they are detected both in the Bacillus intact cells and the cells culture medium by MALDI-TOF mass spectrometry. The cyclic lipopeptides self-assemble in water media producing negatively charged and large aggregates (300-800 nm of mean hydrodynamic radius) as evaluated by dynamic light scattering and zeta-potential analysis. The aggregate size depends on pH and ionic strength. However, it is not affected by changes in the osmolarity of the outer medium suggesting the absence of an internal aqueous compartment despite the occurrence of low molecular weight phospholipids in their composition as determined from inorganic phosphorus analysis. The activity against a sensitive Bacillus cereus strain was evaluated from inhibition halos and B. cereus lysis. Essential features determining the antibiotic activity on susceptible Bacillus cereus cells are the preserved cyclic moiety conferring cyclic lipopeptides resistance to proteases and the medium pH. The aggregates are inactive per se at the pH of the culture medium which is around 6 or below. The knock out of the sensitive cells only takes place when the aggregates are disassembled due to a high negative charge at pH above 6.

  1. The Self-Assembly of a Cyclic Lipopeptides Mixture Secreted by a B. megaterium Strain and Its Implications on Activity against a Sensitive Bacillus Species

    PubMed Central

    Pueyo, Manuel T.; Mutafci, Bruna A.; Soto-Arriaza, Marco A.; Di Mascio, Paolo; Carmona-Ribeiro, Ana M.

    2014-01-01

    Cyclic lipopeptides are produced by a soil Bacillus megaterium strain and several other Bacillus species. In this work, they are detected both in the Bacillus intact cells and the cells culture medium by MALDI-TOF mass spectrometry. The cyclic lipopeptides self-assemble in water media producing negatively charged and large aggregates (300–800 nm of mean hydrodynamic radius) as evaluated by dynamic light scattering and zeta-potential analysis. The aggregate size depends on pH and ionic strength. However, it is not affected by changes in the osmolarity of the outer medium suggesting the absence of an internal aqueous compartment despite the occurrence of low molecular weight phospholipids in their composition as determined from inorganic phosphorus analysis. The activity against a sensitive Bacillus cereus strain was evaluated from inhibition halos and B. cereus lysis. Essential features determining the antibiotic activity on susceptible Bacillus cereus cells are the preserved cyclic moiety conferring cyclic lipopeptides resistance to proteases and the medium pH. The aggregates are inactive per se at the pH of the culture medium which is around 6 or below. The knock out of the sensitive cells only takes place when the aggregates are disassembled due to a high negative charge at pH above 6. PMID:24816927

  2. The timing of induced resistance and induced susceptibility in the soybean-Mexican bean beetle system.

    PubMed

    Underwood, Nora C

    1998-04-01

    Induced plant responses to herbivory have been demonstrated in many systems. It has been suggested that the timing of these responses may influence the impact of induced resistance on herbivore populations, and may affect the evolution of induced defenses. This study used a bioassay to characterize the time course of systemic induced responses to Mexican bean beetle herbivory in four genotypes of soybeans. The results suggest that the time course of induced responses in this system is more complex than most previous studies have indicated. Herbivory provoked both rapid induced resistance and subsequent induced susceptibility to beetle feeding. All four genotypes of soybean induced significant resistance to beetle damage (beetles preferred undamaged to damaged plants) by 3 days after damage. By 15 days after damage, this resistance had decayed (beetles showed no preference for undamaged over damaged plants), and by 20 days after damage, all four genotypes exhibited significant induced susceptibility (beetles preferred previously damaged plants over undamaged plants). The magnitude of induced resistance in each genotype correlated strongly with the magnitude of induced susceptibility in that genotype.

  3. Characterization of an inducible oxidative stress system in Bacillus subtilis.

    PubMed

    Bol, D K; Yasbin, R E

    1990-06-01

    Exponentially growing cells of Bacillus subtilis demonstrated inducible protection against killing by hydrogen peroxide when prechallenged with a nonlethal dose of this oxidative agent. Cells deficient in a functional recE+ gene product were as much as 100 times more sensitive to the H2O2 but still exhibited an inducible protective response. Exposure to hydrogen peroxide also induced the recE(+)-dependent DNA damage-inducible (din) genes, the resident prophage, and the product of the recE+ gene itself. Thus hydrogen peroxide is capable of inducing the SOS-like or SOB system of B. subtilis. However, the induction of this DNA repair system by other DNA-damaging agents is not sufficient to activate the protective response to hydrogen peroxide. Therefore, at least one more regulatory network (besides the SOB system) that responds to oxidative stress must exist. Furthermore, the data presented indicate that a functional catalase gene is necessary for this protective response.

  4. Systemic cold-induced urticaria--clinical and laboratory characterization.

    PubMed

    Kivity, S; Schwartz, Y; Wolf, R; Topilsky, M

    1990-01-01

    Six patients are described with a history of cold-related urticaria in whom standard tests (water-immersion and ice-cube) did not induce symptoms. Only total-body cold exposure induced generalized urticaria. Systemic cold urticaria should, therefore, be included in the differential diagnosis of cold-dependent allergic disorders.

  5. Cyclic Lipopeptides of Bacillus amyloliquefaciens subsp. plantarum Colonizing the Lettuce Rhizosphere Enhance Plant Defense Responses Toward the Bottom Rot Pathogen Rhizoctonia solani.

    PubMed

    Chowdhury, Soumitra Paul; Uhl, Jenny; Grosch, Rita; Alquéres, Sylvia; Pittroff, Sabrina; Dietel, Kristin; Schmitt-Kopplin, Philippe; Borriss, Rainer; Hartmann, Anton

    2015-09-01

    The commercially available inoculant Bacillus amyloliquefaciens FZB42 is able to considerably reduce lettuce bottom rot caused by Rhizoctonia solani. To understand the interaction between FZB42 and R. solani in the rhizosphere of lettuce, we used an axenic system with lettuce bacterized with FZB42 and inoculated with R. solani. Confocal laser scanning microscopy showed that FZB42 could delay the initial establishment of R. solani on the plants. To show which secondary metabolites of FZB42 are produced under these in-situ conditions, we developed an ultra-high performance liquid chromatography coupled to time of flight mass spectrometry-based method and identified surfactin, fengycin, and bacillomycin D in the lettuce rhizosphere. We hypothesized that lipopeptides and polyketides play a role in enhancing the plant defense responses in addition to the direct antagonistic effect toward R. solani and used a quantitative real-time polymerase chain reaction-based assay for marker genes involved in defense signaling pathways in lettuce. A significant higher expression of PDF 1.2 observed in the bacterized plants in response to subsequent pathogen challenge showed that FZB42 could enhance the lettuce defense response toward the fungal pathogen. To identify if surfactin or other nonribosomally synthesized secondary metabolites could elicit the observed enhanced defense gene expression, we examined two mutants of FZB42 deficient in production of surfactin and the lipopetides and polyketides, by expression analysis and pot experiments. In the absence of surfactin and other nonribosomally synthesized secondary metabolites, there was no enhanced PDF 1.2-mediated response to the pathogen challenge. Pot experiment results showed that the mutants failed to reduce disease incidence in lettuce as compared with the FZB42 wild type, indicating, that surfactin as well as other nonribosomally synthesized secondary metabolites play a role in the actual disease suppression and on lettuce

  6. Biological Role of Paenilarvins, Iturin-Like Lipopeptide Secondary Metabolites Produced by the Honey Bee Pathogen Paenibacillus larvae.

    PubMed

    Hertlein, Gillian; Seiffert, Marlene; Gensel, Sebastian; Garcia-Gonzalez, Eva; Ebeling, Julia; Skobalj, Ranko; Kuthning, Anja; Süssmuth, Roderich D; Genersch, Elke

    2016-01-01

    The Gram-positive bacterium Paenibacillus larvae (P. larvae) is the causative agent of a deadly honey bee brood disease called American Foulbrood (AFB). AFB is a notifiable epizootic in most countries and, hence, P. larvae is of considerable relevance for veterinarians and apiculturists alike. Over the last decade, much progress has been made in the understanding of the (patho)biology of P. larvae. Recently, several non-ribosomally produced peptides (NRP) and peptide/polyketide (NRP/PK) hybrids produced by P. larvae were identified. Among these NRPs were iturin-like lipopeptides, the paenilarvins A-C. Iturins are known to exhibit strong anti-fungal activity; for some iturins, cytotoxic activity towards mammalian erythrocytes and human cancer cell lines are described. We here present our results on the analysis of the natural function of the paenilarvins during pathogenesis of P. larvae infections. We demonstrated production of paenilarvins in infected larvae. However, we could neither demonstrate cytotoxicity of paenilarvins towards cultured insect cells nor towards larvae in feeding assays. Accordingly, exposure bioassays performed with larvae infected by wild-type P. larvae and a knockout mutant of P. larvae lacking production of paenilarvins did not substantiate a role for the paenilarvins as virulence factor. Further experiments are necessary to analyze the relevance of the paenilarvins' anti-fungal activity for P. larvae infections in the presence of fungal competitors in the larval midgut or cadaver.

  7. Biological Role of Paenilarvins, Iturin-Like Lipopeptide Secondary Metabolites Produced by the Honey Bee Pathogen Paenibacillus larvae

    PubMed Central

    Gensel, Sebastian; Garcia-Gonzalez, Eva; Ebeling, Julia; Skobalj, Ranko; Kuthning, Anja; Süssmuth, Roderich D.

    2016-01-01

    The Gram-positive bacterium Paenibacillus larvae (P. larvae) is the causative agent of a deadly honey bee brood disease called American Foulbrood (AFB). AFB is a notifiable epizootic in most countries and, hence, P. larvae is of considerable relevance for veterinarians and apiculturists alike. Over the last decade, much progress has been made in the understanding of the (patho)biology of P. larvae. Recently, several non-ribosomally produced peptides (NRP) and peptide/polyketide (NRP/PK) hybrids produced by P. larvae were identified. Among these NRPs were iturin-like lipopeptides, the paenilarvins A-C. Iturins are known to exhibit strong anti-fungal activity; for some iturins, cytotoxic activity towards mammalian erythrocytes and human cancer cell lines are described. We here present our results on the analysis of the natural function of the paenilarvins during pathogenesis of P. larvae infections. We demonstrated production of paenilarvins in infected larvae. However, we could neither demonstrate cytotoxicity of paenilarvins towards cultured insect cells nor towards larvae in feeding assays. Accordingly, exposure bioassays performed with larvae infected by wild-type P. larvae and a knockout mutant of P. larvae lacking production of paenilarvins did not substantiate a role for the paenilarvins as virulence factor. Further experiments are necessary to analyze the relevance of the paenilarvins’ anti-fungal activity for P. larvae infections in the presence of fungal competitors in the larval midgut or cadaver. PMID:27760211

  8. Lipopeptides from the Banyan Endophyte, Bacillus subtilis K1: Mass Spectrometric Characterization of a Library of Fengycins

    NASA Astrophysics Data System (ADS)

    Pathak, Khyati V.; Keharia, Haresh; Gupta, Kallol; Thakur, Suman S.; Balaram, Padmanabhan

    2012-10-01

    Mass spectrometric analysis of a banyan endophyte, Bacillus subtilis K1, extract showing broad spectrum antifungal activity revealed a complex mixture of lipopeptides, iturins, surfactins, and fengycins. Fractionation by reversed-phase high performance liquid chromatography (HPLC) facilitated a detailed analysis of fengycin microheterogeneity. Matrix assisted laser desorption ionization (MALDI) and electrospray ionization (ESI) mass spectrometric studies permitted the identification of several new fengycin variants. Four major sites of heterogeneity are identified: (1) N-terminus β-hydroxy fatty acid moiety, where chain length variation and the presence of unsaturation occur, (2) position 6 (Ala/Val/Ile/Leu), (3) position 10 (Val/Ile) within the macrocyclic ring, and (4) Gln to Glu replacement at position 8, resulting in fengycin variants that differ in mass by 1 Da. Diagnostic fragment ions provide a quick method for localizing the sites of variation in the macrocycle or the linear segment. Subsequent establishment of the sequences is achieved by MS/MS analysis of linear fengycin species produced by hydrolysis of the macrocyclic lactone. Unsaturation in the fatty acid chain and the presence of linear precursors in the B. subtilis K1 extract are also established by mass spectrometry. The anomalous distribution of intensities within isotopic multiplets is a diagnostic for Gln/Glu replacements. High resolution mass spectrometry facilitates the identification of fengycin species differing by 1 Da by localizing the variable position (Gln8/Glu8) in the fengycin variants.

  9. Lipid nanocapsule functionalization by lipopeptides derived from human papillomavirus type-16 capsid for nucleic acid delivery into cancer cells.

    PubMed

    Weyland, M; Griveau, A; Bejaud, J; Benoit, J-P; Coursaget, P; Garcion, E

    2013-10-01

    Plasmid DNA (pDNA) and small interfering RNAs (siRNAs) are very useful tools for the treatment of cancer. However, pDNA and siRNAs efficacy is restricted by their negative charge and susceptibility to degradation by endonucleases that prevent them penetrating tissue and cellular barriers such as the plasma and endolysosomal membranes. Viral vectors have some advantages but their use is largely limited by their immunogenicity. On the other hand, synthetic nanoparticles have advantage of being relatively non-immunogenic but their ability to deliver nucleic acids remains less efficient than their viral counterparts. The present study is focussed on the development and evaluation of biomimetic lipid nanocapsules (LNCs) functionalized with a L1 papillomavirus type-16 capsid-derived lipopeptide on their surface, for transfection of U87MG glioma cells and Caco-2 colorectal adenocarcinoma cells with pDNA or siRNAs. Since the L1-peptide has been described as a nuclear localization signal able to complex with nucleic acids and bind to heparan sulfate on the cell surface, the structure and function of L1-peptide bound to LNCs (L1-LNCs) were investigated. Although L1-LNCs were shown to complex with both pDNA and siRNAs, the pDNA-L1-LNC complexes showed only weak transfection efficiency. In contrast, siRNA-L1-LNC complexes appeared as effective repressors of targeted messengers.

  10. Detection of the Lipopeptide Pam3CSK4 Using a Hybridized Toll-like Receptor Electrochemical Sensor.

    PubMed

    She, Zhe; Topping, Kristin; Ma, Tianxiao; Zhao, Tiantian; Zhou, Wenxia; Kamal, Ajar; Ahmadi, Soha; Kraatz, Heinz-Bernhard

    2017-04-12

    Electrochemical detection of Pam3CSK4, a synthetic triacylated lipopeptide that mimics the structural moieties of its natural Gram negative bacterial pathogen-associated molecular pattern (PAMP) counterpart, has been achieved using hybridized toll-like receptors (TLR) combining TLR1 and TLR2 onto a single sensor surface. These sensors represent the first hybridized TLR sensors. The limit of detection for Pam3CSK4 attained was 7.5 μg/mL, which is within the same order of magnitude for that of the more labor-intensive and time-consuming cell-assay technique, 2.0 μg/mL. The results gathered in these electrochemical experiments show that sensors fabricated by immobilizing a mixture of cooperative TLR1 and -2 generate higher responses when exposed to the analyte in comparison to the control sensors fabricated using pure TLR1 or -2 standalone. A PAMP selectivity test was carried out in line with our inspiration from the mammalian innate immune response. TLRs1-5 as standalone biorecognition elements and the hybridized "TLR1 and 2" sensor surface were investigated, understanding the known TLR-PAMP interactions, through the exploitation of this electrochemical sensor fabrication technique. The experimental result is consistent with observations from previously published in vivo and in vitro studies, and it is the first demonstration of the simultaneous evaluation of electrochemical responses from multiple, unique fabricated TLR sensor surfaces against the same analyte.

  11. New Cyclic Lipopeptides of the Iturin Class Produced by Saltern-Derived Bacillus sp. KCB14S006

    PubMed Central

    Son, Sangkeun; Ko, Sung-Kyun; Jang, Mina; Kim, Jong Won; Kim, Gil Soo; Lee, Jae Kyoung; Jeon, Eun Soo; Futamura, Yushi; Ryoo, In-Ja; Lee, Jung-Sook; Oh, Hyuncheol; Hong, Young-Soo; Kim, Bo Yeon; Takahashi, Shunji; Osada, Hiroyuki; Jang, Jae-Hyuk; Ahn, Jong Seog

    2016-01-01

    Salterns, one of the most extreme natural hypersaline environments, are a rich source of halophilic and halotolerant microorganisms, but they remain largely underexplored ecological niches in the discovery of bioactive secondary metabolites. In continued efforts to investigate the metabolic potential of microbial populations from chemically underexplored sites, three new lipopeptides named iturin F1, iturin F2 and iturin A9 (1–3), along with iturin A8 (4), were isolated from Bacillus sp. KCB14S006 derived from a saltern. The structures of the isolated compounds were established by 1D-, 2D-NMR and HR-ESIMS, and their absolute configurations were determined by applying advanced Marfey’s method and CD spectroscopy. All isolates exhibited significant antifungal activities against various pathogenic fungi and moderate cytotoxic activities toward HeLa and srcts-NRK cell lines. Moreover, in an in vitro enzymatic assay, compound 4 showed a significant inhibitory activity against indoleamine 2,3-dioxygenase. PMID:27049393

  12. Antibiotic and Biosurfactant Properties of Cyclic Lipopeptides Produced by Fluorescent Pseudomonas spp. from the Sugar Beet Rhizosphere

    PubMed Central

    Nielsen, T. H.; Sørensen, D.; Tobiasen, C.; Andersen, J. B.; Christophersen, C.; Givskov, M.; Sørensen, J.

    2002-01-01

    Cyclic lipopeptides (CLPs) with antibiotic and biosurfactant properties are produced by a number of soil bacteria, including fluorescent Pseudomonas spp. To provide new and efficient strains for the biological control of root-pathogenic fungi in agricultural crops, we isolated approximately 600 fluorescent Pseudomonas spp. from two different agricultural soils by using three different growth media. CLP production was observed in a large proportion of the strains (approximately 60%) inhabiting the sandy soil, compared to a low proportion (approximately 6%) in the loamy soil. Chemical structure analysis revealed that all CLPs could be clustered into two major groups, each consisting of four subgroups. The two major groups varied primarily in the number of amino acids in the cyclic peptide moiety, while each of the subgroups could be differentiated by substitutions of specific amino acids in the peptide moiety. Production of specific CLPs could be affiliated with Pseudomonas fluorescens strain groups belonging to biotype I, V, or VI. In vitro analysis using both purified CLPs and whole-cell P. fluorescens preparations demonstrated that all CLPs exhibited strong biosurfactant properties and that some also had antibiotic properties towards root-pathogenic microfungi. The CLP-producing P. fluorescens strains provide a useful resource for selection of biological control agents, whether a single strain or a consortium of strains was used to maximize the synergistic effect of multiple antagonistic traits in the inoculum. PMID:12089023

  13. Lipid composition in a strain of Bacillus subtilis, a producer of iturin A lipopeptides that are active against uropathogenic bacteria.

    PubMed

    Bernat, Przemysław; Paraszkiewicz, Katarzyna; Siewiera, Paulina; Moryl, Magdalena; Płaza, Grażyna; Chojniak, Joanna

    2016-10-01

    Urinary tract infections are a common disease in humans. Therefore, new methods are needed to destroy biofilms that are formed by uropathogens. Iturin A lipopeptides (LPs) C14 and C15 are potent biosurfactants synthetized by the Bacillus subtilis I'1a strain. The biological activity of extracted LPs was confirmed by examining extracts from I'1a cultures against uropathogenic bacteria that had been isolated from biofilms on urinary catheters. Compared with cultures of DSM 3257, which produce surfactin at a relatively low level, the extract obtained from strain I'1a exhibited a greater inhibitory effect against both planktonic and sessile forms of Escherichia coli, Serratia marcescens, Enterobacter cloacae, Proteus mirabilis, Citrobacter freundii and Enterococcus faecalis. Moreover, cyclic LP biosurfactants may disturb the integrity of cytoplasmic membranes; therefore, we investigated the effects of synthetized LPs on fatty acids and phospholipids of B. subtilis. LPs and lipids were analyzed using GC-MS, LC-MS/MS and MALDI-TOF/TOF techniques. Compared with B. subtilis DSM 3257, membranes of the I'1a strain were characterized by an increased amount of anteiso fatty acids and a ten-fold higher ratio of phosphatidylglycerol (PG)-to-phosphatidylethanolamine (PE). Interestingly, in cultures of B. subtilis DSM 3257 supplemented with LP extracts of the I'1a strain, the PG-to-PE ratio was fourfold higher, and the amount of anteiso fatty acids was also increased.

  14. Migration-induced architectures of planetary systems.

    PubMed

    Szuszkiewicz, Ewa; Podlewska-Gaca, Edyta

    2012-06-01

    The recent increase in number of known multi-planet systems gives a unique opportunity to study the processes responsible for planetary formation and evolution. Special attention is given to the occurrence of mean-motion resonances, because they carry important information about the history of the planetary systems. At the early stages of the evolution, when planets are still embedded in a gaseous disc, the tidal interactions between the disc and planets cause the planetary orbital migration. The convergent differential migration of two planets embedded in a gaseous disc may result in the capture into a mean-motion resonance. The orbital migration taking place during the early phases of the planetary system formation may play an important role in shaping stable planetary configurations. An understanding of this stage of the evolution will provide insight on the most frequently formed architectures, which in turn are relevant for determining the planet habitability. The aim of this paper is to present the observational properties of these planetary systems which contain confirmed or suspected resonant configurations. A complete list of known systems with such configurations is given. This list will be kept by us updated from now on and it will be a valuable reference for studying the dynamics of extrasolar systems and testing theoretical predictions concerned with the origin and the evolution of planets, which are the most plausible places for existence and development of life.

  15. Cutaneous innate immune sensing of Toll-like receptor 2-6 ligands suppresses T cell immunity by inducing myeloid-derived suppressor cells.

    PubMed

    Skabytska, Yuliya; Wölbing, Florian; Günther, Claudia; Köberle, Martin; Kaesler, Susanne; Chen, Ko-Ming; Guenova, Emmanuella; Demircioglu, Doruk; Kempf, Wolfgang E; Volz, Thomas; Rammensee, Hans-Georg; Schaller, Martin; Röcken, Martin; Götz, Friedrich; Biedermann, Tilo

    2014-11-20

    Skin is constantly exposed to bacteria and antigens, and cutaneous innate immune sensing orchestrates adaptive immune responses. In its absence, skin pathogens can expand, entering deeper tissues and leading to life-threatening infectious diseases. To characterize skin-driven immunity better, we applied living bacteria, defined lipopeptides, and antigens cutaneously. We found suppression of immune responses due to cutaneous infection with Gram-positive S. aureus, which was based on bacterial lipopeptides. Skin exposure to Toll-like receptor (TLR)2-6-binding lipopeptides, but not TLR2-1-binding lipopeptides, potently suppressed immune responses through induction of Gr1(+)CD11b(+) myeloid-derived suppressor cells (MDSCs). Investigating human atopic dermatitis, in which Gram-positive bacteria accumulate, we detected high MDSC amounts in blood and skin. TLR2 activation in skin resident cells triggered interleukin-6 (IL-6), which induced suppressive MDSCs, which are then recruited to the skin suppressing T cell-mediated recall responses such as dermatitis. Thus, cutaneous bacteria can negatively regulate skin-driven immune responses by inducing MDSCs via TLR2-6 activation.

  16. Minocycline suppresses morphine-induced respiratory depression, suppresses morphine-induced reward, and enhances systemic morphine-induced analgesia

    PubMed Central

    Hutchinson, Mark R.; Northcutt, Alexis L.; Chao, Lindsey W.; Kearney, Jeffrey J.; Zhang, Yingning; Berkelhammer, Debra L.; Loram, Lisa C.; Rozeske, Robert R.; Bland, Sondra T.; Maier, Steven F.; Gleeson, Todd T.; Watkins, Linda R.

    2008-01-01

    Recent data suggest that opioids can activate immune-like cells of the central nervous system (glia). This opioid-induced glial activation is associated with decreased analgesia, owing to the release of proinflammatory mediators. Here we examine in rats whether the putative microglial inhibitor, minocycline, may affect morphine-induced respiratory depression and/or morphine-induced reward (conditioned place preference). Systemic co-administration of minocycline significantly attenuated morphine-induced reductions in tidal volume, minute volume, inspiratory force and expiratory force, but did not affect morphine-induced reductions in respiratory rate. Minocycline attenuation of respiratory depression was also paralleled with significant attenuation by minocycline of morphine-induced reductions in blood oxygen saturation. Minocycline also attenuated morphine conditioned place preference. Minocycline did not simply reduce all actions of morphine, as morphine analgesia was significantly potentiated by minocycline co-administration. Lastly, morphine dose-dependently increased cyclooxygenase-1 gene expression in a rat microglial cell line, an effect that was dose-dependently blocked by minocycline. Together, these data support that morphine can directly activate microglia in a minocycline-suppressible manner and suggest a pivotal role for minocycline-sensitive processes in the mechanisms of morphine-induced respiration depression, reward, and pain modulation. PMID:18706994

  17. Noise Induced Switching in Delayed Systems

    DTIC Science & Technology

    2012-04-27

    Hamiltonian . In many cases, as in general descriptions of finite population interactions [38], it is not possible to use the Lagrangian approach. In the general...the Hamiltonian or Lagrangian formulation will work to describe the trajectory of the switching optimal path. For additive noise, the second order...When considering dynamical systems with isolated feedback mechanisms or coupling devices to connect a network, there always exists a finite time for the

  18. A Lipopeptide-Based αvβ₃ Integrin-Targeted Ultrasound Contrast Agent for Molecular Imaging of Tumor Angiogenesis.

    PubMed

    Yan, Fei; Xu, Xiuxia; Chen, Yihan; Deng, Zhiting; Liu, Hongmei; Xu, Jianrong; Zhou, Jie; Tan, Guanghong; Wu, Junru; Zheng, Hairong

    2015-10-01

    The design and fabrication of targeted ultrasound contrast agents are key factors in the success of ultrasound molecular imaging applications. Here, we introduce a transformable αvβ3 integrin-targeted microbubble (MB) by incorporation of iRGD-lipopeptides into the MB membrane for non-invasive ultrasound imaging of tumor angiogenesis. First, the iRGD-lipopeptides were synthesized by conjugating iRGD peptides to distearoylphosphatidylethanolamine-polyethylene glycol 2000-maleimide. The resulting iRGD-lipopeptides were used for fabrication of the iRGD-carrying αvβ3 integrin-targeted MBs (iRGD-MBs). The binding specificity of iRGD-MBs for endothelial cells was found to be significantly stronger than that of control MBs (p < 0.01) under in vitro static and dynamic conditions. The binding of iRGD-MBs on the endothelial cells was competed off by pre-incubation with the anti-αv or anti-β3 antibody (p < 0.01). Ultrasound images taken of mice bearing 4T1 breast tumors after intravenous injections of iRGD-MBs or control MBs revealed strong contrast enhancement within the tumors from iRGD-MBs but not from the control MBs; the mean acoustic signal intensity was 10.71 ± 2.75 intensity units for iRGD-MBs versus 1.13 ± 0.18 intensity units for the control MBs (p < 0.01). The presence of αvβ3 integrin was confirmed by immunofluorescence staining. These data indicate that iRGD-MBs can be used as an ultrasound imaging probe for the non-invasive molecular imaging of tumor angiogenesis, and may have further implications for ultrasound image-guided tumor targeting drug delivery.

  19. Optical communication system performance with tracking error induced signal fading.

    NASA Technical Reports Server (NTRS)

    Tycz, M.; Fitzmaurice, M. W.; Premo, D. A.

    1973-01-01

    System performance is determined for an optical communication system using noncoherent detection in the presence of tracking error induced signal fading assuming (1) binary on-off modulation (OOK) with both fixed and adaptive threshold receivers, and (2) binary polarization modulation (BPM). BPM is shown to maintain its inherent 2- to 3-dB advantage over OOK when adaptive thresholding is used, and to have a substantially greater advantage when the OOK system is restricted to a fixed decision threshold.

  20. Bicarbonate trigger for inducing lipid accumulation in algal systems

    SciTech Connect

    Gardner, Robert; Peyton, Brent; Cooksey, Keith E.

    2015-08-04

    The present invention provides bicarbonate containing and/or bicarbonate-producing compositions and methods to induce lipid accumulation in an algae growth system, wherein the algae growth system is under light-dark cycling condition. By adding said compositions at a specific growth stage, said methods lead to much higher lipid accumulation and/or significantly reduced total time required for accumulating lipid in the algae growth system.

  1. Antillatoxin, a novel lipopeptide, enhances neurite outgrowth in immature cerebrocortical neurons through activation of voltage-gated sodium channels.

    PubMed

    Jabba, S V; Prakash, A; Dravid, S M; Gerwick, W H; Murray, T F

    2010-03-01

    Antillatoxin (ATX) is a structurally novel lipopeptide that activates voltage-gated sodium channels (VGSC) leading to sodium influx in cerebellar granule neurons and cerebrocortical neurons 8 to 9 days in vitro (Li et al., 2001; Cao et al., 2008). However, the precise recognition site for ATX on the VGSC remains to be defined. Inasmuch as elevation of intracellular sodium ([Na(+)](i)) may increase N-methyl-d-aspartate receptor (NMDAR)-mediated Ca(2+) influx, Na(+) may function as a signaling molecule. We hypothesized that ATX may enhance neurite outgrowth in cerebrocortical neurons by elevating [Na(+)](i) and augmenting NMDAR function. ATX (30-100 nM) robustly stimulated neurite outgrowth, and this enhancement was sensitive to the VGSC antagonist, tetrodotoxin. To unambiguously demonstrate the enhancement of NMDA receptor function by ATX, we recorded single-channel currents from cell-attached patches. ATX was found to increase the open probability of NMDA receptors. Na(+)-dependent up-regulation of NMDAR function has been shown to be regulated by Src family kinase (SFK) (Yu and Salter, 1998). The Src kinase inhibitor PP2 abrogated ATX-enhanced neurite outgrowth, suggesting a SFK involvement in this response. ATX-enhanced neurite outgrowth was also inhibited by the NMDAR antagonist, (5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine hydrogen maleate (MK-801), and the calmodulin-dependent kinase kinase (CaMKK) inhibitor, 1,8-naphthoylene benzimidazole-3-carboxylic acid (STO-609), demonstrating the requirement for NMDAR activation with subsequent downstream engagement of the Ca(2+)-dependent CaMKK pathway. These results with the structurally and mechanistically novel natural product, ATX, confirm and generalize our earlier results with a neurotoxin site 5 ligand. These data suggest that VGSC activators may represent a novel pharmacological strategy to regulate neuronal plasticity through NMDAR-dependent mechanisms.

  2. Biosynthesis, Chemical Structure, and Structure-Activity Relationship of Orfamide Lipopeptides Produced by Pseudomonas protegens and Related Species

    PubMed Central

    Ma, Zongwang; Geudens, Niels; Kieu, Nam P.; Sinnaeve, Davy; Ongena, Marc; Martins, José C.; Höfte, Monica

    2016-01-01

    Orfamide-type cyclic lipopeptides (CLPs) are biosurfactants produced by Pseudomonas and involved in lysis of oomycete zoospores, biocontrol of Rhizoctonia and insecticidal activity against aphids. In this study, we compared the biosynthesis, structural diversity, in vitro and in planta activities of orfamides produced by rhizosphere-derived Pseudomonas protegens and related Pseudomonas species. Genetic characterization together with chemical identification revealed that the main orfamide compound produced by the P. protegens group is orfamide A, while the related strains Pseudomonas sp. CMR5c and CMR12a produce orfamide B. Comparison of orfamide fingerprints led to the discovery of two new orfamide homologs (orfamide F and orfamide G) in Pseudomonas sp. CMR5c. The structures of these two CLPs were determined by nuclear magnetic resonance (NMR) and mass spectrometry (MS) analysis. Mutagenesis and complementation showed that orfamides determine the swarming motility of parental Pseudomonas sp. strain CMR5c and their production was regulated by luxR type regulators. Orfamide A and orfamide B differ only in the identity of a single amino acid, while orfamide B and orfamide G share the same amino acid sequence but differ in length of the fatty acid part. The biological activities of orfamide A, orfamide B, and orfamide G were compared in further bioassays. The three compounds were equally active against Magnaporthe oryzae on rice, against Rhizoctonia solani AG 4-HGI in in vitro assays, and caused zoospore lysis of Phytophthora and Pythium. Furthermore, we could show that orfamides decrease blast severity in rice plants by blocking appressorium formation in M. oryzae. Taken all together, our study shows that orfamides produced by P. protegens and related species have potential in biological control of a broad spectrum of fungal plant pathogens. PMID:27065956

  3. A new infusion pathway monitoring system utilizing electrostatic induced potential.

    PubMed

    Maki, Hiromichi; Yonezawa, Yoshiharu; Ogawa, Hidekuni; Ninomiya, Ishio; Sada, Kouji; Hamada, Shingo; Hahn, Alien W; Caldwell, W Morton

    2006-01-01

    We have developed a new infusion pathway monitoring system employing linear integrated circuits and a low-power 8-bit single chip microcomputer. The system is available for hospital and home use and it constantly monitors the intactness of the pathway. The sensor is an electro-conductive polymer electrode wrapped around the infusion polyvinyl chloride infusion tube. This records an AC (alternating current) voltage induced on the patient's body by electrostatic coupling from the normal 100 volt, 60 Hz AC power line wiring field in the patient's room. If the injection needle or infusion tube becomes detached, then the system detects changes in the induced AC voltage and alerts the nursing station, via the nurse call system or PHS (personal handy phone System).

  4. Misalignment induced aberration off-axis optical system

    NASA Astrophysics Data System (ADS)

    Pang, Zhihai; Fan, Xuewu; Ma, Zhen; Zou, Gangyi

    2016-10-01

    Through introducing transformed pupil vector and shifted center of aberration fields vector into the nodal aberration expansions of an axially symmetric optical system, the aberration expression in third order of an off-axis optical system and misaligned off-axis optical system are detailed. Nodal aberration characteristics of misaligned off-axis optical system are revealed only by analyzing the pupil decentration vector, aberration fields shifted vector and the aberration coefficients of the axially symmetric optical system. Actually, it is well demonstrated that the 3rd spherical aberration, 3rd coma, 3rd astigmatism in a misalignment off-axis system are comparable to the aberrations in a misalignment axially symmetric system. Otherwise it will not only induced constant 3rd spherical aberration but also constant 3rd coma and 3rd astigmatism over the field of view, when aligned an off-axis optical system elements with error axial spacing.

  5. Functional and molecular characterization of a lipopeptide surfactant from the marine sponge-associated eubacteria Bacillus licheniformis NIOT-AMKV06 of Andaman and Nicobar Islands, India.

    PubMed

    Lawrance, Anburajan; Balakrishnan, Meena; Joseph, Toms Cheriath; Sukumaran, Dheenan Palaiya; Valsalan, Vinithkumar Nambali; Gopal, Dharani; Ramalingam, Kirubagaran

    2014-05-15

    The production of a lipopeptide surfactant from the sponge-associated eubacteria Bacillus licheniformis NIOT-AMKV06 from the Andaman and Nicobar Islands was investigated. The highest production was attained with glucose and yeast extracts as the carbon and nitrogen sources (1.789 mg mL(-1)), respectively. The surfactant was highly stable over a pH range of 5.0-10 and a temperature range of 20-70°C with high NaCl concentrations. Excellent emulsification activity was exhibited by the purified surfactant with crude oil, kerosene, and diesel. A two-fold increase in surfactant production (3.0 mg mL(-1)) was observed using the newly formulated medium in this study. The surfactant biosynthesis gene cluster (sfp, sfpO, and srfA) from B. licheniformis NIOT-AMKV06 was heterologously expressed in Escherichia coli, and the production was increased three-fold (11.78 g L(-1)) over the original strain. The results confirm the potential of the surfactant for use in bioremediation of hydrocarbons in a marine environment and for enhanced oil recovery. To our knowledge, this is the first report on the ability of a hydrocarbon degrading B. licheniformis from marine sponges for the biosynthesis of a potent lipopeptide surfactant possessing characteristics of maximum stability, outstanding surfactant activity, and exceptional emulsifying capability.

  6. Application of extracellular lipopeptide biosurfactant produced by endophytic Bacillus subtilis K1 isolated from aerial roots of banyan (Ficus benghalensis) in microbially enhanced oil recovery (MEOR).

    PubMed

    Pathak, Khyati V; Keharia, Hareshkumar

    2014-02-01

    Bacillus subtilis K1 isolated from aerial roots of banyan tree secreted mixture of surfactins, iturins and fengycins with high degree of heterogeneity. The extracellular extract consisting of mixture of these cyclic lipopeptides exhibited very good emulsification activity as well as excellent emulsion stability. The culture accumulated maximum surfactant up to 48 h of growth during batch fermentation in Luria broth. The emulsion of hexane, heptane and octane prepared using 48-h-old culture supernatant of B. subtilis K1 remained stable up to 2 days while emulsion of four stroke engine oil remained stable for more than a year. The critical micelle concentration of crude lipopeptide biosurfactant extracted by acid precipitation from 48-h-old fermentation broth of B. subtilis K1 was found to be 20.5 μg/mL. The biosurfactant activity was found to be stable at 100 °C for 2 h, over a pH range of 6-12 h and over an NaCl concentration up to 10 % (w/v). The application of biosurfactant on laboratory scale sand pack column saturated with four stroke engine oil resulted in ~43 % enhanced oil recovery, suggesting its suitability in microbially enhanced oil recovery.

  7. Simulated systemic recurrent Mycoplasma infection in rats induces recurrent sickness responses without residual impairment in spatial learning and memory.

    PubMed

    Swanepoel, Tanya; Harvey, Brian H; Harden, Lois M; Laburn, Helen P; Mitchell, Duncan

    2012-02-01

    In spite of their prevalence and importance, recurrent acute infections seldom have been investigated in the laboratory. We set out to measure fever and sickness behaviour in simulated recurrent Mycoplasma infection; Mycoplasma is a common clinical cause of recurrent acute infection. Male Sprague-Dawley rats had radiotransponders implanted to measure abdominal temperature and cage activity. After recovery, rats received three intraperitoneal (I.P.) injections, 10 days apart, of either fibroblast-stimulating lipopeptide-1 (FLS-1), a pyrogenic moiety of Mycoplasma salivarium, at a dose of 500 μg.kg(-1) in 1 ml.kg(-1) phosphate-buffered saline (PBS), or vehicle (PBS, 1 ml.kg(-1)). Body mass and food intake were measured daily. For measurement of learning and memory, training in a Morris Water Maze commenced 10 days after the last of the three successive injections and continued daily for 4 days. Spatial memory was assessed on the following day. Hippocampal tissue of rats was collected on the day of the last exposure to the maze. Recurrent FSL-1 administration induced recurrent fevers (~1°C) for about 9h, recurrent lethargy (~40-60%) for 1 day, recurrent anorexia (~16-30%) for 1 day, and recurrent reductions in the rate of mass gain (~112%) for 1 day, but did not induce persistent stunting. Recurrent FSL-1 administration did not result in tolerance to fever, lethargy or anorexia. There was no residual histological damage to the hippocampus and no residual detrimental effect in learning or memory in rats. Though we cannot extrapolate our results directly to humans, clinical recurrent acute Mycoplasma infection may not impose a high risk of stunting or impaired spatial learning and memory.

  8. BIOCONAID System (Bionic Control of Acceleration Induced Dimming). Final Report.

    ERIC Educational Resources Information Center

    Rogers, Dana B.; And Others

    The system described represents a new technique for enhancing the fidelity of flight simulators during high acceleration maneuvers. This technique forces the simulator pilot into active participation and energy expenditure similar to the aircraft pilot undergoing actual accelerations. The Bionic Control of Acceleration Induced Dimming (BIOCONAID)…

  9. Data acquisition system used in radiation induced electrical degradation experiments

    SciTech Connect

    White, D.P.

    1995-04-01

    Radiation induced electrical degradation (RIED) of ceramic materials has recently been reported and is the topic of much research at the present time. The object of this report is to describe the data acquisition system for an experiment designed to study RIED at the High Flux Beam Reactor (HFBR) at Brookhaven National Laboratory.

  10. Fungal colonization of an Ordovician impact-induced hydrothermal system

    PubMed Central

    Ivarsson, Magnus; Broman, Curt; Sturkell, Erik; Ormö, Jens; Siljeström, Sandra; van Zuilen, Mark; Bengtson, Stefan

    2013-01-01

    Impacts are common geologic features on the terrestrial planets throughout the solar system, and on at least Earth and Mars impacts have induced hydrothermal convection. Impact-generated hydrothermal systems have been suggested to possess the same life supporting capability as hydrothermal systems associated with volcanic activity. However, evidence of fossil microbial colonization in impact-generated hydrothermal systems is scarce in the literature. Here we report of fossilized microorganisms in association with cavity-grown hydrothermal minerals from the 458 Ma Lockne impact structure, Sweden. Based on morphological characteristics the fossilized microorganisms are interpreted as fungi. We further infer the kerogenization of the microfossils, and thus the life span of the fungi, to be contemporaneous with the hydrothermal activity and migration of hydrocarbons in the system. Our results from the Lockne impact structure show that hydrothermal systems associated with impact structures can support colonization by microbial life. PMID:24336641

  11. Fungal colonization of an Ordovician impact-induced hydrothermal system.

    PubMed

    Ivarsson, Magnus; Broman, Curt; Sturkell, Erik; Ormö, Jens; Siljeström, Sandra; van Zuilen, Mark; Bengtson, Stefan

    2013-12-16

    Impacts are common geologic features on the terrestrial planets throughout the solar system, and on at least Earth and Mars impacts have induced hydrothermal convection. Impact-generated hydrothermal systems have been suggested to possess the same life supporting capability as hydrothermal systems associated with volcanic activity. However, evidence of fossil microbial colonization in impact-generated hydrothermal systems is scarce in the literature. Here we report of fossilized microorganisms in association with cavity-grown hydrothermal minerals from the 458 Ma Lockne impact structure, Sweden. Based on morphological characteristics the fossilized microorganisms are interpreted as fungi. We further infer the kerogenization of the microfossils, and thus the life span of the fungi, to be contemporaneous with the hydrothermal activity and migration of hydrocarbons in the system. Our results from the Lockne impact structure show that hydrothermal systems associated with impact structures can support colonization by microbial life.

  12. Non-linear system identification in flow-induced vibration

    SciTech Connect

    Spanos, P.D.; Zeldin, B.A.; Lu, R.

    1996-12-31

    The paper introduces a method of identification of non-linear systems encountered in marine engineering applications. The non-linearity is accounted for by a combination of linear subsystems and known zero-memory non-linear transformations; an equivalent linear multi-input-single-output (MISO) system is developed for the identification problem. The unknown transfer functions of the MISO system are identified by assembling a system of linear equations in the frequency domain. This system is solved by performing the Cholesky decomposition of a related matrix. It is shown that the proposed identification method can be interpreted as a {open_quotes}Gram-Schmidt{close_quotes} type of orthogonal decomposition of the input-output quantities of the equivalent MISO system. A numerical example involving the identification of unknown parameters of flow (ocean wave) induced forces on offshore structures elucidates the applicability of the proposed method.

  13. Code System to Calculate Tornado-Induced Flow Material Transport.

    SciTech Connect

    ANDRAE, R. W.

    1999-11-18

    Version: 00 TORAC models tornado-induced flows, pressures, and material transport within structures. Its use is directed toward nuclear fuel cycle facilities and their primary release pathway, the ventilation system. However, it is applicable to other structures and can model other airflow pathways within a facility. In a nuclear facility, this network system could include process cells, canyons, laboratory offices, corridors, and offgas systems. TORAC predicts flow through a network system that also includes ventilation system components such as filters, dampers, ducts, and blowers. These ventilation system components are connected to the rooms and corridors of the facility to form a complete network for moving air through the structure and, perhaps, maintaining pressure levels in certain areas. The material transport capability in TORAC is very basic and includes convection, depletion, entrainment, and filtration of material.

  14. Fungal colonization of an Ordovician impact-induced hydrothermal system

    NASA Astrophysics Data System (ADS)

    Ivarsson, Magnus; Broman, Curt; Sturkell, Erik; Ormö, Jens; Siljeström, Sandra; van Zuilen, Mark; Bengtson, Stefan

    2013-12-01

    Impacts are common geologic features on the terrestrial planets throughout the solar system, and on at least Earth and Mars impacts have induced hydrothermal convection. Impact-generated hydrothermal systems have been suggested to possess the same life supporting capability as hydrothermal systems associated with volcanic activity. However, evidence of fossil microbial colonization in impact-generated hydrothermal systems is scarce in the literature. Here we report of fossilized microorganisms in association with cavity-grown hydrothermal minerals from the 458 Ma Lockne impact structure, Sweden. Based on morphological characteristics the fossilized microorganisms are interpreted as fungi. We further infer the kerogenization of the microfossils, and thus the life span of the fungi, to be contemporaneous with the hydrothermal activity and migration of hydrocarbons in the system. Our results from the Lockne impact structure show that hydrothermal systems associated with impact structures can support colonization by microbial life.

  15. Cyclic Lipopeptide Biosynthetic Genes and Products, and Inhibitory Activity of Plant-Associated Bacillus against Phytopathogenic Bacteria

    PubMed Central

    Mora, Isabel; Cabrefiga, Jordi; Montesinos, Emilio

    2015-01-01

    The antibacterial activity against bacterial plant pathogens and its relationships with the presence of the cyclic lipopeptide (cLP) biosynthetic genes ituC (iturin), bmyB (bacillomycin), fenD (fengycin) and srfAA (surfactin), and their corresponding antimicrobial peptide products have been studied in a collection of 64 strains of Bacillus spp. isolated from plant environments. The most frequent antimicrobial peptide (AMP) genes were bmyB, srfAA and fenD (34-50% of isolates). Most isolates (98.4%) produced surfactin isoforms, 90.6% iturins and 79.7% fengycins. The antibacterial activity was very frequent and generally intense among the collection of strains because 75% of the isolates were active against at least 6 of the 8 bacterial plant pathogens tested. Hierarchical and correspondence analysis confirmed the presence of two clearly differentiated groups. One group consisted of Bacillus strains that showed a strong antibacterial activity, presented several cLPs genes and produced several isoforms of cLPs simultaneously, mainly composed of B. subtilis and B. amyloliquefaciens, although the last one was exclusive to this group. Another group was characterized by strains with very low or none antibacterial activity, that showed one or none of the cLP genes and produced a few or none of the corresponding cLPs, and was the most heterogenous group including B. subtilis, B. licheniformis, B. megaterium, B. pumilus, B. cereus and B. thuringiensis, although the last two were exclusive to this group. This work demonstrated that the antagonistic capacity of plant-associated Bacillus against plant pathogenic bacteria is related to the presence of cLP genes and to the production of the corresponding cLPs, and it is mainly associated to the species B. subtilis and B. amyloliquefaciens. Our findings would help to increase the yield and efficiency of screening methods to obtain candidate strains to biocontrol agents with a mechanism of action relaying on the production of

  16. Efficacy of FK463, a New Lipopeptide Antifungal Agent, in Mouse Models of Disseminated Candidiasis and Aspergillosis

    PubMed Central

    Ikeda, Fumiaki; Wakai, Yoshimi; Matsumoto, Satoru; Maki, Katsuyuki; Watabe, Etsuko; Tawara, Shuichi; Goto, Toshio; Watanabe, Yuji; Matsumoto, Fumio; Kuwahara, Shogo

    2000-01-01

    The efficacy of intravenous injection of FK463, a novel water-soluble lipopeptide, was evaluated in mouse models of disseminated candidiasis and aspergillosis and was compared with those of fluconazole (FLCZ) and amphotericin B (AMPH-B). In the candidiasis model, FK463 significantly prolonged the survival of intravenously infected mice at doses of 0.125 mg/kg of body weight or higher. In disseminated candidiasis caused by Candida species, including FLCZ-resistant Candida albicans, FK463 exhibited an efficacy 1.4 to 18 times inferior to that of AMPH-B, with 50% effective doses (ED50s) ranging from 0.21 to 1.00 mg/kg and 0.06 to 0.26 mg/kg, respectively, and was much more active than FLCZ. The protective effect of FK463 was not obviously influenced by the fungal inoculum size, the starting time of the treatment, or the immunosuppressed status of the host. The reduction in efficacy was less than that observed with FLCZ or AMPH-B. The efficacy of FK463 was also evaluated in the disseminated candidiasis target organ assay and was compared with those of FLCZ and AMPH-B. Efficacies were evaluated on the basis of a comparison between the mean log10 CFU in kidneys in the groups treated with antifungal agents and that in control group. A single dose of FK463 at 0.5 mg/kg or higher significantly reduced the viable counts in kidneys compared with the numbers of yeast cells before treatment, and its efficacy was comparable to that of AMPH-B, while FLCZ at 4 mg/kg showed only a suppressive effect on the growth of C. albicans in the kidneys. In the disseminated aspergillosis model, FK463 given at doses of 0.5 mg/kg or higher significantly prolonged the survival of mice infected intravenously with Aspergillus fumigatus conidia. The efficacy of FK463 was about 2 times inferior to that of AMPH-B, with ED50s ranging from 0.25 to 0.50 mg/kg and 0.11 to 0.29 mg/kg, respectively. These results indicate that FK463 may be a potent parenterally administered therapeutic agent for

  17. Induced systemic resistance (ISR) in plants: mechanism of action.

    PubMed

    Choudhary, Devendra K; Prakash, Anil; Johri, B N

    2007-12-01

    Plants possess a range of active defense apparatuses that can be actively expressed in response to biotic stresses (pathogens and parasites) of various scales (ranging from microscopic viruses to phytophagous insect). The timing of this defense response is critical and reflects on the difference between coping and succumbing to such biotic challenge of necrotizing pathogens/parasites. If defense mechanisms are triggered by a stimulus prior to infection by a plant pathogen, disease can be reduced. Induced resistance is a state of enhanced defensive capacity developed by a plant when appropriately stimulated. Systemic acquired resistance (SAR) and induced systemic resistance (ISR) are two forms of induced resistance wherein plant defenses are preconditioned by prior infection or treatment that results in resistance against subsequent challenge by a pathogen or parasite. Selected strains of plant growth-promoting rhizobacteria (PGPR) suppress diseases by antagonism between the bacteria and soil-borne pathogens as well as by inducing a systemic resistance in plant against both root and foliar pathogens. Rhizobacteria mediated ISR resembles that of pathogen induced SAR in that both types of induced resistance render uninfected plant parts more resistant towards a broad spectrum of plant pathogens. Several rhizobacteria trigger the salicylic acid (SA)-dependent SAR pathway by producing SA at the root surface whereas other rhizobacteria trigger different signaling pathway independent of SA. The existence of SA-independent ISR pathway has been studied in Arabidopsis thaliana, which is dependent on jasmonic acid (JA) and ethylene signaling. Specific Pseudomonas strains induce systemic resistance in viz., carnation, cucumber, radish, tobacco, and Arabidopsis, as evidenced by an enhanced defensive capacity upon challenge inoculation. Combination of ISR and SAR can increase protection against pathogens that are resisted through both pathways besides extended protection to a

  18. Acute Ozone-Induced Pulmonary and Systemic Metabolic ...

    EPA Pesticide Factsheets

    Acute ozone exposure increases circulating stress hormones and induces peripheral metabolic alterations in animals and humans. We hypothesized that the increase of adrenal-derived stress hormones is necessary for ozone-induced systemic metabolic effects and lung injury. Male Wistar-Kyoto rats (12 week-old) underwent total bilateral adrenalectomy (ADREX), adrenal demedullation (DEMED) or sham surgery (SHEM). After 4 day recovery, rats were exposed to air or ozone (1ppm), 4h/day for 1 or 2 days. Circulating adrenaline levels dropped to nearly zero in DEMED and ADREX rats relative to air-exposed SHAM. Corticosterone levels tended to be low in DEMED rats and dropped to nearly zero in ADREX rats. Adrenalectomy in air-exposed rats caused modest changes in metabolites and lung toxicity parameters. Ozone-induced hyperglycemia and glucose intolerance were markedly attenuated in DEMED with nearly complete reversal in ADREX rats. Ozone increased circulating epinephrine and corticosterone in SHAM but not in DEMED or ADREX rats. Free fatty acids and branched-chain amino acids tended to increase after ozone exposure in SHAM but not in DEMED or ADREX rats. Lung minute volume was not affected by surgery or ozone but ozone-induced labored breathing was less pronounced in ADREX rats. Ozone-induced increases in lung protein leakage and neutrophilic inflammation were markedly reduced in DEMED and ADREX rats (ADREX>DMED). Ozone-mediated decrease in circulating WBC in SHAM was not

  19. Membrane interactions of fusogenic coiled-coil peptides: implications for lipopeptide mediated vesicle fusion.

    PubMed

    Rabe, Martin; Schwieger, Christian; Zope, Harshal R; Versluis, Frank; Kros, Alexander

    2014-07-08

    Fusion of lipid membranes is an important natural process for the intra- and intercellular exchange of molecules. However, little is known about the actual fusion mechanism at the molecular level. In this study we examine a system that models the key features of this process. For the molecular recognition between opposing membranes two membrane anchored heterodimer coiled-coil forming peptides called 'E' (EIAALEK)3 and 'K' (KIAALKE)3 were used. Lipid monolayers and IR reflection absorption spectroscopy (IRRAS) revealed the interactions of the peptides 'E', 'K', and their parallel coiled-coil complex 'E/K' with the phospholipid membranes and thereby mimicked the pre- and postfusion states, respectively. The peptides adopted α-helical structures and were incorporated into the monolayers with parallel orientation. The strength of binding to the monolayer differed for the peptides and tethering them to the membrane increased the interactions even further. Remarkably, these interactions played a role even in the postfusion state. These findings shed light on important mechanistic details of the membrane fusion process in this model system. Furthermore, their implications will help to improve the rational design of new artificial membrane fusion systems, which have a wide range of potential applications in supramolecular chemistry and biomedicine.

  20. Imaging of Drug-induced Complications in the Gastrointestinal System.

    PubMed

    McGettigan, Melissa J; Menias, Christine O; Gao, Zhenqiang J; Mellnick, Vincent M; Hara, Amy K

    2016-01-01

    Drug-induced injury commonly affects the gastrointestinal and hepatobiliary systems because of the mechanisms of absorption and metabolism. In pill esophagitis, injury is frequently related to direct contact with the esophageal mucosa, resulting in small superficial ulcers in the mid esophagus. Nonsteroidal anti-inflammatory drugs can lead to gastrointestinal tract ulcers and small bowel mucosal diaphragms (thin weblike strictures). Injury to the pancreatic and hepatobiliary systems can manifest as pancreatitis, acute or chronic hepatitis, cholestasis, or steatosis and steatohepatitis (which may progress to cirrhosis). Various drugs may also insult the hepatic vasculature, resulting in Budd-Chiari and sinusoidal obstructive syndromes. Focal lesions such as hepatic adenomas may develop after use of oral contraceptives or anabolic steroids. Ultrasonography, computed tomography, and magnetic resonance imaging can aid in diagnosis of drug-induced injuries and often are necessary to exclude other causes.

  1. Ultrashort Laser Pulse Induced Electromagnetic Stress on Biological Macromolecular Systems.

    DTIC Science & Technology

    1979-11-01

    ULTRASHORT LASER PULSE INDUCED ~~~~~ ELECTROMAGNET IC STRESS ON BIOLOGICAL MACROMOLECULAR SYSTEMS Adam P. Bruckner , Ph.D. ( i~iiCJ. Michael ...AFSC, Brooks Air Force Base, Texas. Dr. John Taboada (RZL) was the Laboratory Project Scientjst..in...Charge When U.S. Goverrijie~t drawings...available to the general public , including foreignnations. Thi s technical report has been reviewed and is approved for publ i-cation. OHN TABOADA , Ph.D

  2. Lactose-Inducible System for Metabolic Engineering of Clostridium ljungdahlii

    PubMed Central

    Ueki, Toshiyuki; Nevin, Kelly P.; Lovley, Derek R.

    2014-01-01

    The development of tools for genetic manipulation of Clostridium ljungdahlii has increased its attractiveness as a chassis for autotrophic production of organic commodities and biofuels from syngas and microbial electrosynthesis and established it as a model organism for the study of the basic physiology of acetogenesis. In an attempt to expand the genetic toolbox for C. ljungdahlii, the possibility of adapting a lactose-inducible system for gene expression, previously reported for Clostridium perfringens, was investigated. The plasmid pAH2, originally developed for C. perfringens with a gusA reporter gene, functioned as an effective lactose-inducible system in C. ljungdahlii. Lactose induction of C. ljungdahlii containing pB1, in which the gene for the aldehyde/alcohol dehydrogenase AdhE1 was downstream of the lactose-inducible promoter, increased expression of adhE1 30-fold over the wild-type level, increasing ethanol production 1.5-fold, with a corresponding decrease in acetate production. Lactose-inducible expression of adhE1 in a strain in which adhE1 and the adhE1 homolog adhE2 had been deleted from the chromosome restored ethanol production to levels comparable to those in the wild-type strain. Inducing expression of adhE2 similarly failed to restore ethanol production, suggesting that adhE1 is the homolog responsible for ethanol production. Lactose-inducible expression of the four heterologous genes necessary to convert acetyl coenzyme A (acetyl-CoA) to acetone diverted ca. 60% of carbon flow to acetone production during growth on fructose, and 25% of carbon flow went to acetone when carbon monoxide was the electron donor. These studies demonstrate that the lactose-inducible system described here will be useful for redirecting carbon and electron flow for the biosynthesis of products more valuable than acetate. Furthermore, this tool should aid in optimizing microbial electrosynthesis and for basic studies on the physiology of acetogenesis. PMID:24509933

  3. Lactose-Inducible System for Metabolic Engineering of Clostridium ljungdahlii

    SciTech Connect

    Banerjee, A; Leang, C; Ueki, T; Nevin, KP; Lovley, DR

    2014-03-25

    The development of tools for genetic manipulation of Clostridium ljungdahlii has increased its attractiveness as a chassis for autotrophic production of organic commodities and biofuels from syngas and microbial electrosynthesis and established it as a model organism for the study of the basic physiology of acetogenesis. In an attempt to expand the genetic toolbox for C. ljungdahlii, the possibility of adapting a lactose-inducible system for gene expression, previously reported for Clostridium perfringens, was investigated. The plasmid pAH2, originally developed for C. perfringens with a gusA reporter gene, functioned as an effective lactose-inducible system in C. ljungdahlii. Lactose induction of C. ljungdahlii containing pB1, in which the gene for the aldehyde/alcohol dehydrogenase AdhE1 was downstream of the lactose-inducible promoter, increased expression of adhE1 30-fold over the wild-type level, increasing ethanol production 1.5-fold, with a corresponding decrease in acetate production. Lactose-inducible expression of adhE1 in a strain in which adhE1 and the adhE1 homolog adhE2 had been deleted from the chromosome restored ethanol production to levels comparable to those in the wild-type strain. Inducing expression of adhE2 similarly failed to restore ethanol production, suggesting that adhE1 is the homolog responsible for ethanol production. Lactose-inducible expression of the four heterologous genes necessary to convert acetyl coenzyme A (acetyl-CoA) to acetone diverted ca. 60% of carbon flow to acetone production during growth on fructose, and 25% of carbon flow went to acetone when carbon monoxide was the electron donor. These studies demonstrate that the lactose-inducible system described here will be useful for redirecting carbon and electron flow for the biosynthesis of products more valuable than acetate. Furthermore, this tool should aid in optimizing microbial electrosynthesis and for basic studies on the physiology of acetogenesis.

  4. A green-light inducible lytic system for cyanobacterial cells

    PubMed Central

    2014-01-01

    Background Cyanobacteria are an attractive candidate for the production of biofuel because of their ability to capture carbon dioxide by photosynthesis and grow on non-arable land. However, because huge quantities of water are required for cultivation, strict water management is one of the greatest issues in algae- and cyanobacteria-based biofuel production. In this study, we aim to construct a lytic cyanobacterium that can be regulated by a physical signal (green-light illumination) for future use in the recovery of biofuel related compounds. Results We introduced T4 bacteriophage-derived lysis genes encoding holin and endolysin under the control of the green-light regulated cpcG2 promoter in Synechocystis sp. PCC 6803. When cells harboring the lysis genes were illuminated with both red and green light, we observed a considerable decrease in growth rate, a significant increase in cellular phycocyanin released in the medium, and a considerable fraction of dead cells. These effects were not observed when these cells were illuminated with only red light, or when cells not containing the lysis genes were grown under either red light or red and green light. These results indicate that our constructed green-light inducible lytic system was clearly induced by green-light illumination, resulting in lytic cells that released intracellular phycocyanin into the culture supernatant. This property suggests a future possibility to construct photosynthetic genetically modified organisms that are unable to survive under sunlight exposure. Expression of the self-lysis system with green-light illumination was also found to greatly increase the fragility of the cell membrane, as determined by subjecting the induced cells to detergent, osmotic-shock, and freeze-thaw treatments. Conclusions A green-light inducible lytic system was constructed in Synechocystis sp. PCC 6803. The engineered lytic cyanobacterial cells should be beneficial for the recovery of biofuels and related compounds

  5. Towards the Understanding of Induced Seismicity in Enhanced Geothermal Systems

    SciTech Connect

    Gritto, Roland; Dreger, Douglas; Heidbach, Oliver

    2014-08-29

    This DOE funded project was a collaborative effort between Array Information Technology (AIT), the University of California at Berkeley (UCB), the Helmholtz Centre Potsdam - German Research Center for Geosciences (GFZ) and the Lawrence Berkeley National Laboratory (LBNL). It was also part of the European research project “GEISER”, an international collaboration with 11 European partners from six countries including universities, research centers and industry, with the goal to address and mitigate the problems associated with induced seismicity in Enhanced Geothermal Systems (EGS). The goal of the current project was to develop a combination of techniques, which evaluate the relationship between enhanced geothermal operations and the induced stress changes and associated earthquakes throughout the reservoir and the surrounding country rock. The project addressed the following questions: how enhanced geothermal activity changes the local and regional stress field; whether these activities can induce medium sized seismicity M > 3; (if so) how these events are correlated to geothermal activity in space and time; what is the largest possible event and strongest ground motion, and hence the potential hazard associated with these activities. The development of appropriate technology to thoroughly investigate and address these questions required a number of datasets to provide the different physical measurements distributed in space and time. Because such a dataset did not yet exist for an EGS system in the United State, we used current and past data from The Geysers geothermal field in northern California, which has been in operation since the 1960s. The research addressed the need to understand the causal mechanisms of induced seismicity, and demonstrated the advantage of imaging the physical properties and temporal changes of the reservoir. The work helped to model the relationship between injection and production and medium sized magnitude events that have

  6. Exposure of Mice to Topical Bovine Thrombin Induces Systemic Autoimmunity

    PubMed Central

    Schoenecker, Jonathan G.; Johnson, Rachel K.; Lesher, Aaron P.; Day, Jarrod D.; Love, Stephanie D.; Hoffman, Maureane R.; Ortel, Thomas L.; Parker, William; Lawson, Jeffrey H.

    2001-01-01

    Bovine thrombin is used as an aid to hemostasis in medical and surgical procedures. At least 500,000 Americans are exposed to this therapeutic annually and reports suggest that exposure is associated with the development of autoreactive antibodies. To determine whether bovine thrombin can induce pathological autoimmunity we exposed nonautoimmune-prone galactose-α1-3-galactose-deficient mice to the two bovine thrombin preparations currently approved for use in the United States. We found that, like humans exposed to bovine thrombin, mice developed an immune response against the therapeutic and the xenogeneic carbohydrate galactose-α1-3-galactose, and some mice developed autoantibodies against clotting factors. Further, unexpectedly, a single exposure to this therapeutic also induced autoimmunity with features characteristic of systemic lupus erythematosus including antibodies against nuclear antigens, native DNA, double-stranded DNA, and cardiolipin. High levels of these autoantibodies correlated with glomerulonephritis in all mice evaluated. This autoimmune syndrome was detected in mice 15 weeks after a secondary exposure to bovine thrombin and female mice were found to develop the syndrome at a significantly greater frequency than males. Thus, these studies indicate that exposure to bovine thrombin preparations can induce a pathological systemic autoimmune syndrome with lupus-like serology. PMID:11696457

  7. Platelets protect lung from injury induced by systemic inflammatory response

    PubMed Central

    Luo, Shuhua; Wang, Yabo; An, Qi; Chen, Hao; Zhao, Junfei; Zhang, Jie; Meng, Wentong; Du, Lei

    2017-01-01

    Systemic inflammatory responses can severely injure lungs, prompting efforts to explore how to attenuate such injury. Here we explored whether platelets can help attenuate lung injury in mice resulting from extracorporeal circulation (ECC)-induced systemic inflammatory responses. Mice were subjected to ECC for 30 min, then treated with phosphate-buffered saline, platelets, the GPIIb/IIIa inhibitor Tirofiban, or the combination of platelets and Tirofiban. Blood and lung tissues were harvested 60 min later, and lung injury and inflammatory status were assessed. As expected, ECC caused systemic inflammation and pulmonary dysfunction, and platelet transfusion resulted in significantly milder lung injury and higher lung function. It also led to greater numbers of circulating platelet-leukocyte aggregates and greater platelet accumulation in the lung. Platelet transfusion was associated with higher production of transforming growth factor-β and as well as lower levels of tumour necrosis factor-α and neutrophil elastase in plasma and lung. None of these platelet effects was observed in the presence of Tirofiban. Our results suggest that, at least under certain conditions, platelets can protect lung from injury induced by systemic inflammatory responses. PMID:28155889

  8. Expression of caveolin-1 and podocalyxin in rat lungs challenged with 2-kDa macrophage-activating lipopeptide and Flt3L.

    PubMed

    Tschernig, T; Pabst, R; Kasper, M; El-Hadi, Mustafa; Singh, B

    2014-04-01

    Caveolin-1 is one of the important regulators of vascular permeability in inflamed lungs. Podocalyxin is a CD34 protein expressed on vascular endothelium and has a role in podocyte development in the kidney. Few data are available on the expression of caveolin-1 and podocalyxin in lungs challenged with Toll-like receptor 2 (TLR2) agonists such as mycoplasma-derived macrophage activating lipopeptide or with immune modulators such as Fms-like tyrosine kinase receptor-3 ligand (Flt3L), which expands dendritic cell populations in the lung. Because of the significance of pathogen-derived molecules that act through TLR2 and of the role of immune modulators in lung physiology, we examine the immunohistochemical expression of caveolin-1 and podocalyxin in lungs from rats challenged with a 2-kDa macrophage-activating lipopeptide (MALP-2) and Flt3L. Normal rat lungs expressed caveolin-1 in alveolar septa, vascular endothelium and airway epithelium, especially along the lateral borders of epithelial cells but not in alveolar macrophages. MALP-2 and Flt3L decreased and increased, respectively, the expression of caveolin-1. Caveolin-1 expression seemed to increase in microvessels in bronchiole-associated lymphoid tissue (BALT) in Flt3L-challenged lungs but not in normal or MALP-2-treated lungs. Podocalyxin was absent in the epithelium and alveolar macrophages but was present in the vasculature of control, Flt3L- and MALP-2-treated rats. Compared with control and MALP-2-treated rats, Flt3L-treated lungs showed greater expression of podocalyxin in BALT vasculature and at the interface of monocytes and the endothelium. These immunohistochemical data describing the altered expression of caveolin-1 and podocalyxin in lungs treated with MALP-2 or Flt3L encourage further mechanistic studies on the role of podocalyxin and caveolin-1 in lung inflammation.

  9. An IPTG Inducible Conditional Expression System for Mycobacteria

    PubMed Central

    Ravishankar, Sudha; Ambady, Anisha; Ramu, Haripriya; Mudugal, Naina Vinay; Tunduguru, Ragadeepthi; Anbarasu, Anand; Sharma, Umender K.; Sambandamurthy, Vasan K.; Ramaiah, Sudha

    2015-01-01

    Conditional expression strains serve as a valuable tool to study the essentiality and to establish the vulnerability of a target under investigation in a drug discovery program. While essentiality implies an absolute requirement of a target function, vulnerability provides valuable information on the extent to which a target function needs to be depleted to achieve bacterial growth inhibition followed by cell death. The critical feature of an ideal conditional expression system is its ability to tightly regulate gene expression to achieve the full spectrum spanning from a high level of expression in order to support growth and near zero level of expression to mimic conditions of gene knockout. A number of bacterial conditional expression systems have been reported for use in mycobacteria. The utility of an isopropylthiogalactoside (IPTG) inducible system in mycobacteria has been reported for protein overexpression and anti-sense gene expression from a replicating multi-copy plasmid. Herein, we report the development of a versatile set of non-replicating IPTG inducible vectors for mycobacteria which can be used for generation of conditional expression strains through homologous recombination. The role of a single lac operator versus a double lac operator to regulate gene expression was evaluated by monitoring the expression levels of β-galactosidase in Mycobacterium smegmatis. These studies indicated a significant level of leaky expression from the vector with a single lac operator but none from the vector with double lac operator. The significance of the double lac operator vector for target validation was established by monitoring the growth kinetics of an inhA, a rpoB and a ftsZ conditional expression strain grown in the presence of different concentrations of IPTG. The utility of this inducible system in identifying target specific inhibitors was established by screening a focussed library of small molecules using an inhA and a rpoB conditional expression

  10. Inducible repair system in Haemophilus influenzae unaccompanied by mutation. [uv

    SciTech Connect

    Notani, N.K.; Setlow, J.K.

    1980-07-01

    Weigle reactivation of ultraviolet-irradiated HPlc1 phage was observed after ultraviolet or mitomycin C treatment of Haemophilus influenzae cells. The amount of reactivation was considerably increased when the treated cells were incubated in growth medium before infection. The presence of chloramphenicol during this incubation abolished the reactivation. No mutation of this phage accompanied the reactivation. When cells were treated so as to produce a maximal reactivation of phage, neither reactivation nor mutation of cells was observed. It is concluded that H. influenzae has an inducible repair system that is not accompanied by mutation.

  11. Characterization of Two Inducible Phosphate Transport Systems in Rhizobium tropici

    PubMed Central

    Botero, Lina M.; Al-Niemi, Thamir S.; McDermott, Timothy R.

    2000-01-01

    Rhizobium tropici forms nitrogen-fixing nodules on the roots of the common bean (Phaseolus vulgaris). Like other legume-Rhizobium symbioses, the bean-R. tropici association is sensitive to the availability of phosphate (Pi). To better understand phosphorus movement between the bacteroid and the host plant, Pi transport was characterized in R. tropici. We observed two Pi transport systems, a high-affinity system and a low-affinity system. To facilitate the study of these transport systems, a Tn5B22 transposon mutant lacking expression of the high-affinity transport system was isolated and used to characterize the low-affinity transport system in the absence of the high-affinity system. The Km and Vmax values for the low-affinity system were estimated to be 34 ± 3 μM Pi and 118 ± 8 nmol of Pi · min−1 · mg (dry weight) of cells−1, respectively, and the Km and Vmax values for the high-affinity system were 0.45 ± 0.01 μM Pi and 86 ± 5 nmol of Pi · min−1 · mg (dry weight) of cells−1, respectively. Both systems were inducible by Pi starvation and were also shock sensitive, which indicated that there was a periplasmic binding-protein component. Neither transport system appeared to be sensitive to the proton motive force dissipator carbonyl cyanide m-chlorophenylhydrazone, but Pi transport through both systems was eliminated by the ATPase inhibitor N,N′-dicyclohexylcarbodiimide; the Pi transport rate was correlated with the intracellular ATP concentration. Also, Pi movement through both systems appeared to be unidirectional, as no efflux or exchange was observed with either the wild-type strain or the mutant. These properties suggest that both Pi transport systems are ABC type systems. Analysis of the transposon insertion site revealed that the interrupted gene exhibited a high level of homology with kdpE, which in several bacteria encodes a cytoplasmic response regulator that governs responses to low potassium contents and/or changes in medium

  12. Biomedical implications of heavy metals induced imbalances in redox systems.

    PubMed

    Sharma, Bechan; Singh, Shweta; Siddiqi, Nikhat J

    2014-01-01

    Several workers have extensively worked out the metal induced toxicity and have reported the toxic and carcinogenic effects of metals in human and animals. It is well known that these metals play a crucial role in facilitating normal biological functions of cells as well. One of the major mechanisms associated with heavy metal toxicity has been attributed to generation of reactive oxygen and nitrogen species, which develops imbalance between the prooxidant elements and the antioxidants (reducing elements) in the body. In this process, a shift to the former is termed as oxidative stress. The oxidative stress mediated toxicity of heavy metals involves damage primarily to liver (hepatotoxicity), central nervous system (neurotoxicity), DNA (genotoxicity), and kidney (nephrotoxicity) in animals and humans. Heavy metals are reported to impact signaling cascade and associated factors leading to apoptosis. The present review illustrates an account of the current knowledge about the effects of heavy metals (mainly arsenic, lead, mercury, and cadmium) induced oxidative stress as well as the possible remedies of metal(s) toxicity through natural/synthetic antioxidants, which may render their effects by reducing the concentration of toxic metal(s). This paper primarily concerns the clinicopathological and biomedical implications of heavy metals induced oxidative stress and their toxicity management in mammals.

  13. Biomedical Implications of Heavy Metals Induced Imbalances in Redox Systems

    PubMed Central

    Singh, Shweta; Siddiqi, Nikhat J.

    2014-01-01

    Several workers have extensively worked out the metal induced toxicity and have reported the toxic and carcinogenic effects of metals in human and animals. It is well known that these metals play a crucial role in facilitating normal biological functions of cells as well. One of the major mechanisms associated with heavy metal toxicity has been attributed to generation of reactive oxygen and nitrogen species, which develops imbalance between the prooxidant elements and the antioxidants (reducing elements) in the body. In this process, a shift to the former is termed as oxidative stress. The oxidative stress mediated toxicity of heavy metals involves damage primarily to liver (hepatotoxicity), central nervous system (neurotoxicity), DNA (genotoxicity), and kidney (nephrotoxicity) in animals and humans. Heavy metals are reported to impact signaling cascade and associated factors leading to apoptosis. The present review illustrates an account of the current knowledge about the effects of heavy metals (mainly arsenic, lead, mercury, and cadmium) induced oxidative stress as well as the possible remedies of metal(s) toxicity through natural/synthetic antioxidants, which may render their effects by reducing the concentration of toxic metal(s). This paper primarily concerns the clinicopathological and biomedical implications of heavy metals induced oxidative stress and their toxicity management in mammals. PMID:25184144

  14. Unrelated toxin–antitoxin systems cooperate to induce persistence

    PubMed Central

    Fasani, Rick A.; Savageau, Michael A.

    2015-01-01

    Persisters are drug-tolerant bacteria that account for the majority of bacterial infections. They are not mutants, rather, they are slow-growing cells in an otherwise normally growing population. It is known that the frequency of persisters in a population is correlated with the number of toxin–antitoxin systems in the organism. Our previous work provided a mechanistic link between the two by showing how multiple toxin–antitoxin systems, which are present in nearly all bacteria, can cooperate to induce bistable toxin concentrations that result in a heterogeneous population of slow- and fast-growing cells. As such, the slow-growing persisters are a bet-hedging subpopulation maintained under normal conditions. For technical reasons, the model assumed that the kinetic parameters of the various toxin–antitoxin systems in the cell are identical, but experimental data indicate that they differ, sometimes dramatically. Thus, a critical question remains: whether toxin–antitoxin systems from the diverse families, often found together in a cell, with significantly different kinetics, can cooperate in a similar manner. Here, we characterize the interaction of toxin–antitoxin systems from many families that are unrelated and kinetically diverse, and identify the essential determinant for their cooperation. The generic architecture of toxin–antitoxin systems provides the potential for bistability, and our results show that even when they do not exhibit bistability alone, unrelated systems can be coupled by the growth rate to create a strongly bistable, hysteretic switch between normal (fast-growing) and persistent (slow-growing) states. Different combinations of kinetic parameters can produce similar toxic switching thresholds, and the proximity of the thresholds is the primary determinant of bistability. Stochastic fluctuations can spontaneously switch all of the toxin–antitoxin systems in a cell at once. The spontaneous switch creates a heterogeneous population

  15. Differential role of Dok1 and Dok2 in TLR2-induced inflammatory signaling in glia.

    PubMed

    Downer, Eric J; Johnston, Daniel G W; Lynch, Marina A

    2013-09-01

    Accumulating evidence continues to underpin the role of the innate immune system in pathologies associated with neuroinflammation. Innate immunity is regulated by pattern recognition receptors that detect pathogens, and in the case of Gram-positive bacteria, binding of bacterial lipopeptides to toll-like receptor (TLR)2 is emerging as an important mechanism controlling glial cell activation. In the present study, we employed the use of the synthetic bacterial lipoprotein and a selective TLR2 agonist, Pam3CSK4, to induce inflammatory signaling in microglia and astrocytes. The adaptor proteins, downstream of kinase (Dok)1 and Dok2, are known to have a role in negatively regulating the Ras-ERK signaling cascade, with downstream consequences on pro-inflammatory cytokine expression. Data presented herein demonstrate that TLR2 enhanced the tyrosine phosphorylation of Dok1 and Dok2 in astrocytes and microglia, and that knockdown of these adaptors using small interfering RNA robustly elevated TLR2-induced ERK activation. Importantly, TLR2-induced NF-κB activation, and IL-6 production was exacerbated in astrocytes transfected with Dok1 and Dok2 siRNA, indicating that both Dok proteins negatively regulate TLR2-induced inflammatory signaling in astrocytes. In contrast, Dok1 knockdown attenuated TLR2-induced NF-κB activation and IL-6 production in microglia, while Dok2 siRNA failed to affect TLR2-induced NF-κB activity and subsequent cytokine expression in this cell type. Overall, this indicates that Dok1 and Dok2 are novel adaptors for TLR2 in glial cells and importantly indicates that Dok1 and Dok2 differentially regulate TLR2-induced pro-inflammatory signaling in astrocytes and microglia.

  16. Anoxia induces thermotolerance in the locust flight system.

    PubMed

    Wu, B S; Lee, J K; Thompson, K M; Walker, V K; Moyes, C D; Robertson, R M

    2002-03-01

    Heat shock and anoxia are environmental stresses that are known to trigger similar cellular responses. In this study, we used the locust to examine stress cross-tolerance by investigating the consequences of a prior anoxic stress on the effects of a subsequent high-temperature stress. Anoxic stress and heat shock induced thermotolerance by increasing the ability of intact locusts to survive normally lethal temperatures. To determine whether induced thermotolerance observed in the intact animal was correlated with electrophysiological changes, we measured whole-cell K(+) currents and action potentials from locust neurons. K(+) currents recorded from thoracic neuron somata were reduced after anoxic stress and decreased with increases in temperature. Prior anoxic stress and heat shock increased the upper temperature limit for generation of an action potential during a subsequent heat stress. Although anoxia induced thermotolerance in the locust flight system, a prior heat shock did not protect locusts from a subsequent anoxic stress. To determine whether changes in bioenergetic status were implicated in whole-animal cross-tolerance, phosphagen levels and rates of mitochondrial respiration were assayed. Heat shock alone had no effect on bioenergetic status. Prior heat shock allowed rapid recovery after normally lethal heat stress but afforded no protection after a subsequent anoxic stress. Heat shock also afforded no protection against disruption of bioenergetic status after a subsequent exercise stress. These metabolite studies are consistent with the electrophysiological data that demonstrate that a prior exposure to anoxia can have protective effects against high-temperature stress but that heat shock does not induce tolerance to anoxia.

  17. Brain endocannabinoid system is involved in fluoxetine-induced anorexia.

    PubMed

    Zarate, Jon; Churruca, Itziar; Pascual, Jesús; Casis, Luis; Sallés, Joan; Echevarría, Enrique

    2008-06-01

    In order to describe the effects of chronic fluoxetine administration on the brain endocannabinoid system in lean and obese Zucker rats, brain immunostaining for the CB1 and CB1-phosphorylated cannabinoid receptors was carried out. Obese Zucker rats showed significantly increased the numbers of neural cells positively immunostained for the CB1-phosphorylated receptor in the striatum, compared to their lean litter-mates. Chronic fluoxetine administration decreased the number of neural cells immunostained for CB1-phosphorylated receptor in several striatal and hippocampal regions of obese Zucker rats, compared to controls treated with saline. In contrast, no change in CB1-phosphorylated receptor immunostaining was observed in fluoxetine-treated lean rats, with respect to controls. Taken together, these results suggest the involvement of the hippocampal and striatal endocannabinoid receptor system in fluoxetine-induced anorexia in lean and obese Zucker rats.

  18. Microwave-induced thermoacoustic imaging system based on flexible transducer

    NASA Astrophysics Data System (ADS)

    Ji, Zhong; Yang, Sihua; Xing, Da

    2016-10-01

    Microwave-induced thermoacoustic (TA) imaging combines the advantages of high imaging contrast due to electromagnetic absorption and high resolution of the ultrasound technology, and it is a potential alternative imaging technique for biomedical applications, particularly for breast tumor detection. The traditional TA system uses circular-scanning (CS) to obtain complete information to reconstruct a two-dimensional image, however, it needs a large operating space for rotation of the transducers and bulk of coupling medium limiting its medical applications. The linear-scanning (LS) system can overcome these problems partially but usually lose some information and cause image distortion. In this paper, in order to overcome above limitations, a TA imaging system with Sample-Cling-Scanning (SCS) model based on a flexible multi-element transducer is presented. It combines the advantages of both CS and LS modes, and overcome their limitations. Meanwhile, an adaptive back projection algorithm is presented to implement this scanning model. The experimental results show that the proposed system combines advantages including shape adaptation, information integrity, and efficient transmission. These advantages make it a preferred system for TA applications, especially in breast tumor detection.

  19. Insect eggs induce a systemic acquired resistance in Arabidopsis.

    PubMed

    Hilfiker, Olivier; Groux, Raphaël; Bruessow, Friederike; Kiefer, Karin; Zeier, Jürgen; Reymond, Philippe

    2014-12-01

    Although they constitute an inert stage of the insect's life, eggs trigger plant defences that lead to egg mortality or attraction of egg parasitoids. We recently found that salicylic acid (SA) accumulates in response to oviposition by the Large White butterfly Pieris brassicae, both in local and systemic leaves, and that plants activate a response that is similar to the recognition of pathogen-associated molecular patterns (PAMPs), which are involved in PAMP-triggered immunity (PTI). Here we discovered that natural oviposition by P. brassicae or treatment with egg extract inhibit growth of different Pseudomonas syringae strains in Arabidopsis through the activation of a systemic acquired resistance (SAR). This egg-induced SAR involves the metabolic SAR signal pipecolic acid, depends on ALD1 and FMO1, and is accompanied by a stronger induction of defence genes upon secondary infection. Although P. brassicae larvae showed a reduced performance when feeding on Pseudomonas syringae-infected plants, this effect was less pronounced when infected plants had been previously oviposited. Altogether, our results indicate that egg-induced SAR might have evolved as a strategy to prevent the detrimental effect of bacterial pathogens on feeding larvae.

  20. Alcohol induced changes in phosphoinositide signaling system in rat brain

    SciTech Connect

    Pandey, S.; Piano, M.; Schwertz, D.; Davis, J.; Pandey, G. )

    1991-03-11

    Agonist-induced phosphoinositide break down functions as a signal generating system in a manner similar to the C-AMP system. In order to examine if the changes produced by chronic ethanol treatment on membrane lipid composition and metabolism effect the cellular functions of the neuron, the authors have examined the effect of chronic ethanol exposure on norepinephrine (NE) serotonin (5HT) and calcium ionophore (CI) stimulated phosphoinositide (PI) hydrolysis in rat cortical slices. Rats were maintained on liber-decarli diet alcohol and control liquid diet containing isocaloric sucrose substitute for two months. They were then sacrificed and brain was removed for determination of PI turnover. 5HT stimulated {sup 3}H- inositol monophosphate ({sup 3}H-IPI) formation was significantly lower in the cortex of alcohol treated rats as compared to control rats. However, neither CI nor NE stimulated IP1 formation was significantly different from control rats. The results thus indicate that chronic exposure to ethanol decreases 5HT induced PI breakdown in rat cortex. In order to examine if this decrease is related to a decrease in 5HT2 receptors, or decreased in coupling of receptor to the effector pathway, the authors are currently determining the number and affinity of 5HT2 receptors in alcohol treated rats.

  1. Comparative proteomic analysis reveals intracellular targets for bacillomycin L to induce Rhizoctonia solani Kühn hyphal cell death.

    PubMed

    Zhang, Bao; Qin, Yuxuan; Han, Yuzhu; Dong, Chunjuan; Li, Pinglan; Shang, Qingmao

    2016-09-01

    Bacillomycin L, a natural iturinic lipopeptide produced by Bacillus amyloliquefaciens, is characterized by strong antifungal activity against a variety of agronomically important filamentous fungi including Rhizoctonia solani Kühn. To further understand its antifungal actions, proteomes were comparatively studied within R. solani hyphal cells treated with or without bacillomycin L. The results show that 39 proteins were alternatively expressed within cells in response to this lipopeptide, which are involved in stress response, carbohydrate, amino acid and nucleotide metabolism, cellular component organization, calcium homeostasis, protein degradation, RNA processing, gene transcription, and others, suggesting that, in addition to inducing cell membrane permeabilization, iturin exhibits antibiotic activities by targeting intracellular molecules. Based on these results, a model of action of bacillomycin L against R. solani hyphal cells was proposed. Our study provides new insight into the antibiotic mechanisms of iturins.

  2. Ion beam induced luminescence (IBIL) system for imaging of radiation induced changes in materials

    NASA Astrophysics Data System (ADS)

    Marković, N.; Siketić, Z.; Cosic, D.; Jung, H. K.; Lee, N. H.; Han, W.-T.; Jakšić, M.

    2015-01-01

    The progress of construction on the new IBIL (ion beam induced luminescence) spectrometer installed at the ion microprobe facility of the Ruđer Bošković Institute (RBI) is reported. The IBIL system can be used with beams from either 6.0 MV Tandem Van de Graaff or 1.0 MV Tandetron accelerators. Components of the new apparatus and current experimental set-up are described in detail. Measurements with the new IBIL system were performed using a 2 MeV proton microbeam on three sets of samples. This paper gives a summary of the IBIL arrangement capabilities for various problems, emphasising the potential of this technique for radiation damage studies. Due to the relatively good sensitivity of the IBIL spectrometer, integration into the conventional ion beam analysis (IBA) microbeam setup is shown to be possible.

  3. Draft Genome Sequence of Pseudomonas fluorescens LMG 5329, a White Line-Inducing Principle-Producing Bioindicator for the Mushroom Pathogen Pseudomonas tolaasii

    PubMed Central

    Rokni-Zadeh, Hassan; Zarrineh, Peyman

    2013-01-01

    Pseudomonas tolaasii, the causative agent of Agaricus bisporus brown blotch disease, can be identified by the white line reaction, occurring upon confrontation of the tolaasin-producing mushroom pathogen with “Pseudomonas reactans,” producing the lipopeptide white line-inducing principle (WLIP). The draft genome sequence of the WLIP-producing indicator Pseudomonas fluorescens strain LMG 5329 is reported here. PMID:23887909

  4. Production of novel lipopeptide antibiotics related to A54145 by Streptomyces fradiae mutants blocked in biosynthesis of modified amino acids and assignment of lptJ, lptK and lptL gene functions.

    PubMed

    Alexander, Dylan C; Rock, Jessica; Gu, Jian-Qiao; Mascio, Carmela; Chu, Min; Brian, Paul; Baltz, Richard H

    2011-01-01

    A54145 is a complex of lipopeptide antibiotics produced by Streptomyces fradiae. A54145 factors are structurally related to daptomycin, with four modified amino acids, only one of which is present in daptomycin. We generated three mutants defective in lptJ, lptK or lptL, whose gene products are involved in the formation of hydroxy-Asn(3) (hAsn(3)) and methoxy-Asp(9) (moAsp(9)). Each of the mutants produced novel lipopeptides related to A54145 and the profiles allowed assignment of functions for those genes. We constructed strains carrying different combinations of these genes coupled with a mutation in the lptI gene involved in the biosynthesis of 3-methyl-Glu(12) (3mGlu(12)), and all recombinants produced novel lipopeptides. One of the compounds displayed very good antibacterial activity in the presence of bovine surfactant, which interacts with daptomycin or A54145E to inhibit their antibacterial activities.

  5. A Hybrid Non-Ribosomal Peptide/Polyketide Synthetase Containing Fatty-Acyl Ligase (FAAL) Synthesizes the β-Amino Fatty Acid Lipopeptides Puwainaphycins in the Cyanobacterium Cylindrospermum alatosporum

    PubMed Central

    Mareš, Jan; Hájek, Jan; Urajová, Petra; Kopecký, Jiří; Hrouzek, Pavel

    2014-01-01

    A putative operon encoding the biosynthetic pathway for the cytotoxic cyanobacterial lipopeptides puwainphycins was identified in Cylindrospermum alatosporum. Bioinformatics analysis enabled sequential prediction of puwainaphycin biosynthesis; this process is initiated by the activation of a fatty acid residue via fatty acyl-AMP ligase and continued by a multidomain non-ribosomal peptide synthetase/polyketide synthetase. High-resolution mass spectrometry and nuclear magnetic resonance spectroscopy measurements proved the production of puwainaphycin F/G congeners differing in FA chain length formed by either 3-amino-2-hydroxy-4-methyl dodecanoic acid (4-methyl-Ahdoa) or 3-amino-2-hydroxy-4-methyl tetradecanoic acid (4-methyl-Ahtea). Because only one puwainaphycin operon was recovered in the genome, we suggest that the fatty acyl-AMP ligase and one of the amino acid adenylation domains (Asn/Gln) show extended substrate specificity. Our results provide the first insight into the biosynthesis of frequently occurring β-amino fatty acid lipopeptides in cyanobacteria, which may facilitate analytical assessment and development of monitoring tools for cytotoxic cyanobacterial lipopeptides. PMID:25369527

  6. Stochastic resonance in tristable system induced by dichotomous noise

    NASA Astrophysics Data System (ADS)

    Shi, Peiming; Su, Xiao; Han, Dongying

    2016-11-01

    Stochastic resonance (SR) of a tristable system driven by dichotomous noise (DN) is investigated firstly by the mean signal-to-noise ratio gain (SNR-GM). Utilizing an efficiently numerical algorithm, we acquire the asymmetric DN accurately. Then the system responses and the SNR-GM as the signatures of the stochastic resonance are calculated by the fourth-order Runge-Kutta algorithm. It is founded that the change of system parameters a and c in a certain range can induce SR phenomenon. Moreover, with the increase of parameter c, the amplitude of SNR-GM increases and shows the trend of moving to the left. For the different state values of the symmetric DN, the SNR-GM will increase with the increase of state value a1 and b1 but only a highest peak and the interval of SR shift to the left. However, with the increase of forcing frequency, the SNR-GM decreases and the interval of SR moves to right. In addition to, the highest peak of SNR-GM will decrease with the increase of periodic signal amplitude. These results provide a reliable basis for how to realize the parameter selection of stochastic resonance in tristable system driven by DN.

  7. Experimental chaotic quantification in bistable vortex induced vibration systems

    NASA Astrophysics Data System (ADS)

    Huynh, B. H.; Tjahjowidodo, T.

    2017-02-01

    The study of energy harvesting by means of vortex induced vibration systems has been initiated a few years ago and it is considered to be potential as a low water current energy source. The energy harvester is realized by exposing an elastically supported blunt structure under water flow. However, it is realized that the system will only perform at a limited operating range (water flow) that is attributed to the resonance phenomenon that occurs only at a frequency that corresponds to the fluid flow. An introduction of nonlinear elements seems to be a prominent solution to overcome the problem. Among many nonlinear elements, a bistable spring is known to be able to improve the harvested power by a vortex induced vibrations (VIV) based energy converter at the low velocity water flows. However, it is also observed that chaotic vibrations will occur at different operating ranges that will erratically diminish the harvested power and cause a difficulty in controlling the system that is due to the unpredictability in motions of the VIV structure. In order to design a bistable VIV energy converter with improved harvested power and minimum negative effect of chaotic vibrations, the bifurcation map of the system for varying governing parameters is highly on demand. In this study, chaotic vibrations of a VIV energy converter enhanced by a bistable stiffness element are quantified in a wide range of the governing parameters, i.e. damping and bistable gap. Chaotic vibrations of the bistable VIV energy converter are simulated by utilization of a wake oscillator model and quantified based on the calculation of the Lyapunov exponent. Ultimately, a series of experiments of the system in a water tunnel, facilitated by a computer-based force-feedback testing platform, is carried out to validate the existence of chaotic responses. The main challenge in dealing with experimental data is in distinguishing chaotic response from noise-contaminated periodic responses as noise will smear

  8. Epigenetic regulation of inducible gene expression in the immune system.

    PubMed

    Lim, Pek Siew; Li, Jasmine; Holloway, Adele F; Rao, Sudha

    2013-07-01

    T cells are exquisitely poised to respond rapidly to pathogens and have proved an instructive model for exploring the regulation of inducible genes. Individual genes respond to antigenic stimulation in different ways, and it has become clear that the interplay between transcription factors and the chromatin platform of individual genes governs these responses. Our understanding of the complexity of the chromatin platform and the epigenetic mechanisms that contribute to transcriptional control has expanded dramatically in recent years. These mechanisms include the presence/absence of histone modification marks, which form an epigenetic signature to mark active or inactive genes. These signatures are dynamically added or removed by epigenetic enzymes, comprising an array of histone-modifying enzymes, including the more recently recognized chromatin-associated signalling kinases. In addition, chromatin-remodelling complexes physically alter the chromatin structure to regulate chromatin accessibility to transcriptional regulatory factors. The advent of genome-wide technologies has enabled characterization of the chromatin landscape of T cells in terms of histone occupancy, histone modification patterns and transcription factor association with specific genomic regulatory regions, generating a picture of the T-cell epigenome. Here, we discuss the multi-layered regulation of inducible gene expression in the immune system, focusing on the interplay between transcription factors, and the T-cell epigenome, including the role played by chromatin remodellers and epigenetic enzymes. We will also use IL2, a key inducible cytokine gene in T cells, as an example of how the different layers of epigenetic mechanisms regulate immune responsive genes during T-cell activation.

  9. Resveratrol induces chain interdigitation in DPPC cell membrane model systems.

    PubMed

    Longo, Elena; Ciuchi, Federica; Guzzi, Rita; Rizzuti, Bruno; Bartucci, Rosa

    2016-12-01

    Resveratrol is a natural polyphenol found in various plants with potential therapeutic activity as anti-oxidant, anti-inflammatory, cardioprotective and anti-tumoral. Lipid membranes are among cellular components that are targets of its action. In this work ESR of chain labeled lipids, calorimetry, X-ray diffraction and molecular docking are used to study the interaction of resveratrol with membrane model systems of dipalmitoylphosphatidylcholine (DPPC) as a function of resveratrol concentration (0-30 mol% of the lipid) and temperature (10-50°C). Resveratrol incorporated in DPPC bilayers induces considerable motional restriction at the lipid tail termini, removing the gradient of increasing mobility along the chain found in DPPC bilayers in the gel phase. In contrast, it leaves unperturbed the DPPC chain flexibility profile in the liquid-crystalline phase. At low concentration, resveratrol progressively reduces the pre-transition temperature and eliminates the pre-transition for content ≥5mol%. A reduced cooperativity and a downshift of the main transition temperature are observed, especially at high content. The typical diffraction pattern of DPPC multibilayers in the Lβ' phase is converted to a lamellar pattern with reduced d-spacing of untilted lipid chain in a hexagonal packing at 30 mol% of resveratrol. Molecular docking indicates that the energetically favoured anchoring site is the polar headgroup region, where resveratrol acts as a spacer. The overall results are consistent with the formation in DPPC of an interdigitated Lβi gel phase induced by 30 mol% resveratrol.

  10. Triple optomechanical induced transparency in a two-cavity system

    NASA Astrophysics Data System (ADS)

    Shi-Chao, Wu; Li-Guo, Qin; Jun, Jing; Guo-Hong, Yang; Zhong-Yang, Wang

    2016-05-01

    We theoretically investigate the optomechanical induced transparency (OMIT) phenomenon in a two-cavity system which is composed of two optomechanical cavities. Both of the cavities consist of a fixed mirror and a high-Q mechanical resonator, and they couple to each other via a common waveguide. We show that in the presence of a strong pump field applied to one cavity and a weak probe field applied to the other, a triple-OMIT can be observed in the output field at the probe frequency. The two mechanical resonators in the two cavities are identical, but they lead to different quantum interference pathways. The transparency windows are induced by the coupling of the two cavities and the optical pressure radiated to the mechanical resonators, which can be controlled via the power of the pump field and the coupling strength of the two cavities. Project supported by the Strategic Priority Research Program, China (Grant No. XDB01010200), the Hundred Talents Program of the Chinese Academy of Sciences (Grant No. Y321311401), and the National Natural Sciences Foundation of China (Grant Nos. 11347147 and 1547035).

  11. Is modulating virus virulence by induced systemic resistance realistic?

    PubMed

    Faoro, Franco; Gozzo, Franco

    2015-05-01

    Induction of plant resistance, either achieved by chemicals (systemic acquired resistance, SAR) or by rhizobacteria (induced systemic resistance, ISR) is a possible and/or complementary alternative to manage virus infections in crops. SAR mechanisms operating against viruses are diverse, depending on the pathosystem, and may inhibit virus replication as well as cell-to-cell and long-distance movement. Inhibition is often mediated by salicylic acid with the involvement of alternative oxidase and reactive oxygen species. However, salicylate may also stimulate a separate downstream pathway, leading to the induction of an additional mechanism, based on RNA-dependent RNA polymerase 1-mediated RNA silencing. Thus, SAR and RNA silencing would closely cooperate in the defence against virus infection. Despite tremendous recent progress in the knowledge of SAR mechanisms, only a few compounds, including benzothiadiazole and chitosan have been shown to reduce the severity of systemic virus disease in controlled environment and, more modestly, in open field. Finally, ISR induction, has proved to be a promising strategy to control virus disease, particularly by seed bacterization with a mixture of plant growth-promoting rhizobacteria. However, the use of any of these treatments should be integrated with cultivation practices that reduce vector pressure by the use of insecticides, or by Bt crops.

  12. Apparatus, system, and method for laser-induced breakdown spectroscopy

    SciTech Connect

    Effenberger, Jr., Andrew J; Scott, Jill R; McJunkin, Timothy R

    2014-11-18

    In laser-induced breakdown spectroscopy (LIBS), an apparatus includes a pulsed laser configured to generate a pulsed laser signal toward a sample, a constructive interference object and an optical element, each located in a path of light from the sample. The constructive interference object is configured to generate constructive interference patterns of the light. The optical element is configured to disperse the light. A LIBS system includes a first and a second optical element, and a data acquisition module. The data acquisition module is configured to determine an isotope measurement based, at least in part, on light received by an image sensor from the first and second optical elements. A method for performing LIBS includes generating a pulsed laser on a sample to generate light from a plasma, generating constructive interference patterns of the light, and dispersing the light into a plurality of wavelengths.

  13. Opioid system in L-DOPA-induced dyskinesia.

    PubMed

    Pan, Jing; Cai, Huaibin

    2017-01-01

    L-3, 4-Dihydroxyphenylalanine (L-DOPA)-induced dyskinesia (LID) is a major clinical complication in the treatment of Parkinson's disease (PD). This debilitating side effect likely reflects aberrant compensatory responses for a combination of dopaminergic neuron denervation and repeated L-DOPA administration. Abnormal endogenous opioid signal transduction pathways in basal ganglia have been well documented in LID. Opioid receptors have been targeted to alleviate the dyskinesia. However, the exact role of this altered opioid activity is remains under active investigation. In the present review, we discuss the current understanding of opioid signal transduction in the basal ganglia and how the malfunction of opioid signaling contributes to the pathophysiology of LID. Further study of the opioid system in LID may lead to new therapeutic targets and improved treatment of PD patients.

  14. Shock-induced turbulent flow in baffle systems

    SciTech Connect

    Kuhl, A.L.; Reichenbach, H.

    1993-07-01

    Experiments are described on shock propagation through 2-D aligned and staggered baffle systems. Flow visualization was provided by shadow and schlieren photography, recorded by the Cranz-Schardin camera. Also single-frame, infinite-fringe, color interferograms were used. Intuition suggests that this is a rather simple 2-D shock diffraction problem. However, flow visualization reveals that the flow rapidly evolved into a complex 3-D turbulent mixing problem. Mushroom-shaped mixing regions blocked the flow into the next baffle orifice. Thus energy was transferred from the directed kinetic energy (induced by the shock) to rotational energy of turbulent mixing, and then dissipated by molecular effects. These processes dramatically dissipate the strength of the shock wave. The experiments provide an excellent test case that could be used to assess the accuracy of computer code calculations of such problems.

  15. [Radiation-induced tumors of the nervous system in man].

    PubMed

    Hubert, D; Bertin, M

    1993-11-01

    The risk of developing a tumor of the nervous system in humans is analysed in several studies of populations, exposed to ionising radiation for medical reasons, or exposed to military or occupational radiation. The main data come from series of patients who underwent radiotherapy during childhood: a high incidence of tumors of the nervous system is found after irradiation of one to a few grays as treatment of a benign disease (especially tinea capitis), as well as after irradiation at higher doses of a few tens of grays for the treatment of cancer (in particular cerebral irradiation in acute lymphoblastic leukaemia). The type of radiation-induced tumors is variable, but meningioma is more frequent after low doses and glioma and sarcoma after higher doses used in the treatment of neoplastic diseases. A dose-effect relationship appeared between the risk of tumor of the nervous system and the radiation dose. The risk was higher when radiation was delivered at a younger age. Much less data are available after radiotherapy in the adulthood, but an increased risk of cerebral tumor appears in the series of ankylosing spondylitis patients. As for the exposures to radiodiagnosis exams, the main problem is the risk of cerebral tumor in children whose mother has undergone abdominal or pelvic X-rays during pregnancy. No risk of neurologic tumor was found in the A-bomb survivors irradiated at Hiroshima and Nagasaki. Occupational exposure to ionising radiation has been incriminated in the first radiologists exposed to high doses. In nuclear industry workers, the results of epidemiological studies are contradictory and at the present time it is not possible to link their radiologic exposure with a risk of tumor of the nervous system. In populations living near nuclear plants, mortality due to tumors of the nervous system was not increased.

  16. FGF-2 induces neuronal death through upregulation of system xc-.

    PubMed

    Liu, Xiaoqian; Albano, Rebecca; Lobner, Doug

    2014-02-14

    The cystine/glutamate antiporter (system xc-) transports cystine into cell in exchange for glutamate. Fibroblast growth factor-2 (FGF-2) upregulates system xc- selectively on astrocytes, which leads to increased cystine uptake, the substrate for glutathione production, and increased glutamate release. While increased intracellular glutathione can limit oxidative stress, the increased glutamate release can potentially lead to excitotoxicity to neurons. To test this hypothesis, mixed neuronal and glial cortical cultures were treated with FGF-2. Treatment with FGF-2 for 48 h caused a significant neuronal death in these cultures. Cell death was not observed in neuronal-enriched cultures, or astrocyte-enriched cultures, suggesting the toxicity was the result of neuron-glia interaction. Blocking system xc- eliminated the neuronal death as did the AMPA/kainate receptor antagonist 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo[f]quinoxaline-2,3-dione (NBQX), but not the NMDA receptor antagonist memantine. When cultures were exposed directly to glutamate, both NBQX and memantine blocked the neuronal toxicity. The mechanism of this altered profile of glutamate receptor mediated toxicity by FGF-2 is unclear. The selective calcium permeable AMPA receptor antagonist 1-naphthyl acetyl spermine (NASPM) failed to offer protection. The most likely explanation for the results is that 48 h FGF-2 treatment induces AMPA/kainate receptor toxicity through increased system xc- function resulting in increased release of glutamate. At the same time, FGF-2 alters the sensitivity of the neurons to glutamate toxicity in a manner that promotes selective AMPA/kainate receptor mediated toxicity.

  17. Local and systemic inflammatory responses to experimentally induced gingivitis.

    PubMed

    Leishman, Shaneen J; Seymour, Gregory J; Ford, Pauline J

    2013-01-01

    This study profiled the local and systemic inflammatory responses to experimentally induced gingivitis. Eight females participated in a 21-day experimental gingivitis model followed by a 14-day resolution phase. Bleeding on probing and plaque index scores were assessed before, during, and after resolution of gingival inflammation, and samples of saliva, GCF, and plasma were collected. Samples were assessed for biomarkers of inflammation using the BioPlex platform and ELISA. There were no significant changes in GCF levels of cytokines during the experimental phase; however, individual variability in cytokine profiles was noted. During resolution, mean GCF levels of IL-2, IL-6, and TNF-α decreased and were significantly lower than baseline levels (P = 0.003, P = 0.025, and P = 0.007, resp.). Furthermore, changes in GCF levels of IL-2, IL-6, and TNF-α during resolution correlated with changes in plaque index scores (r = 0.88, P = 0.004; r = 0.72, P = 0.042; r = 0.79, P = 0.019, resp.). Plasma levels of sICAM-1 increased significantly during the experimental phase (P = 0.002) and remained elevated and significantly higher than baseline levels during resolution (P < 0.001). These results support the concept that gingivitis adds to the systemic inflammatory burden of an individual.

  18. Monitoring induced denitrification in an artificial aquifer recharge system.

    NASA Astrophysics Data System (ADS)

    Grau-Martinez, Alba; Torrentó, Clara; Folch, Albert; Domènech, Cristina; Otero, Neus; Soler, Albert

    2014-05-01

    literature ɛN values of -4o and -22o respectively (Aravena and Robertson, 1998; Pauwels et al., 2000). Ongoing denitrification batch experiments will allow us to determine the specific nitrogen and oxygen isotopic fractionation induced by the organic reactive layer, in order to estimate more precisely the extent of denitrification during artificial aquifer recharge. These results confirmed that the reactive layer induces denitrification in the recharge ponds area, proving the usefulness of an isotopic approach to characterize water quality improvement occurring during artificial aquifer recharge. References 1. Aravena, R., Robertson, W.D., 1998. Use of multiple isotope tracers to evaluate denitrification in ground water: Study of nitrate from a large-flux septic system plume. Ground Water, 36(6): 975-982. 2. Pauwels, H., J.C., Kloppmann, W., 2000. Denitrification and mixing in a schist aquifer: Influence on water chemistry and isotopes. Chemical Geology, 168(3-4): 307-324. Acknowledgment This study was supported by the projects CGL2011-29975-C04-01 from the Spanish Government, 2009SGR-00103 from the Catalan Government and ENPI/2011/280-008 from the European Commission. Please fill in your abstract text.

  19. Acute systemic rapamycin induces neurobehavioral alterations in rats.

    PubMed

    Hadamitzky, Martin; Herring, Arne; Keyvani, Kathy; Doenlen, Raphael; Krügel, Ute; Bösche, Katharina; Orlowski, Kathrin; Engler, Harald; Schedlowski, Manfred

    2014-10-15

    Rapamycin is a drug with antiproliferative and immunosuppressive properties, widely used for prevention of acute graft rejection and cancer therapy. It specifically inhibits the activity of the mammalian target of rapamycin (mTOR), a protein kinase known to play an important role in cell growth, proliferation and antibody production. Clinical observations show that patients undergoing therapy with immunosuppressive drugs frequently suffer from affective disorders such as anxiety or depression. However, whether these symptoms are attributed to the action of the distinct compounds remains rather elusive. The present study investigated in rats neurobehavioral consequences of acute rapamycin treatment. Systemic administration of a single low dose rapamycin (3mg/kg) led to enhanced neuronal activity in the amygdala analyzed by intracerebral electroencephalography and FOS protein expression 90min after drug injection. Moreover, behavioral investigations revealed a rapamycin-induced increase in anxiety-related behaviors in the elevated plus-maze and in the open-field. The behavioral alterations correlated to enhanced amygdaloid expression of KLK8 and FKBP51, proteins that have been implicated in the development of anxiety and depression. Together, these results demonstrate that acute blockade of mTOR signaling by acute rapamycin administration not only causes changes in neuronal activity, but also leads to elevated protein expression in protein kinase pathways others than mTOR, contributing to the development of anxiety-like behavior. Given the pivotal role of the amygdala in mood regulation, associative learning, and modulation of cognitive functions, our findings raise the question whether therapy with rapamycin may induce alterations in patients neuropsychological functioning.

  20. Noise-induced transitions and resonant effects in nonlinear systems

    NASA Astrophysics Data System (ADS)

    Zaikin, Alexei

    2003-02-01

    Our every-day experience is connected with different acoustical noise or music. Usually noise plays the role of nuisance in any communication and destroys any order in a system. Similar optical effects are known: strong snowing or raining decreases quality of a vision. In contrast to these situations noisy stimuli can also play a positive constructive role, e.g. a driver can be more concentrated in a presence of quiet music. Transmission processes in neural systems are of especial interest from this point of view: excitation or information will be transmitted only in the case if a signal overcomes a threshold. Dr. Alexei Zaikin from the Potsdam University studies noise-induced phenomena in nonlinear systems from a theoretical point of view. Especially he is interested in the processes, in which noise influences the behaviour of a system twice: if the intensity of noise is over a threshold, it induces some regular structure that will be synchronized with the behaviour of neighbour elements. To obtain such a system with a threshold one needs one more noise source. Dr. Zaikin has analyzed further examples of such doubly stochastic effects and developed a concept of these new phenomena. These theoretical findings are important, because such processes can play a crucial role in neurophysics, technical communication devices and living sciences. Unsere alltägliche Erfahrung ist mit verschiedenen akustischen Einfluessen wie Lärm, aber auch Musik verbunden. Jeder weiss, wie Lärm stören kann und Kommunikation behindert oder gar unterbindet. Ähnliche optische Effekte sind bekannt: starkes Schneetreiben oder Regengüsse verschlechtern die Sicht und lassen uns Umrisse nur noch schemenhaft erkennen. Jedoch koennen ähnliche Stimuli auch sehr positive Auswirkungen haben: Autofahrer fahren bei leiser Musik konzentrierter -- die Behauptung von Schulkindern, nur bei dröhnenden Bässen die Mathehausaufgaben richtig rechnen zu können, ist allerdings nicht wissenschaftlich

  1. Inducing sex reversal of the urogenital system of marsupials.

    PubMed

    Renfree, Marilyn B; Chew, Keng Yih; Shaw, Geoff

    2014-01-01

    Marsupials differ from eutherian mammals in their reproductive strategy of delivering a highly altricial young after a short gestation. The young, with its undeveloped organ systems completes its development post-natally, usually within a pouch. The young is dependent on milk with a composition that varies through lactation to support its growth and changing needs as it matures over a lengthy period. Gonadal differentiation occurs after birth, providing a unique opportunity to examine the effects of hormonal manipulations on its sexual differentiation of the highly accessible young. In marsupials a difference in the migration of the urinary ducts around the genital ducts from eutherian mammals results in the unique tammar reproductive tract which has three vaginae and two cervices, and two distinctly separate uteri. In the tammar wallaby, a small member of the kangaroo family, we showed that virilisation of the Wolffian duct, prostate and phallus depends on an alternate androgen pathway, which has now been shown to be important for virilisation in humans. Through hormonal manipulations over differing time periods we have achieved sex reversal of both ovaries and testes, germ cells, genital ducts, prostate and phallus. Whilst we understand many of the mechanisms behind sexual differentiation there are still many lessons to be learned from understanding how sex reversal is achieved by using a model such as the tammar wallaby. This will help guide investigations into the major questions of how and why sex determination is achieved in other species. This review discusses the control and development of the marsupial urogenital system, largely drawn from our studies in the tammar wallaby and our ability to manipulate this system to induce sex reversal.

  2. Sewage Sludge Polycyclic Aromatic Hydrocarbon (PAH) Decontamination Technique Based on the Utilization of a Lipopeptide Biosurfactant Extracted from Corn Steep Liquor.

    PubMed

    Vecino, Xanel; Rodríguez-López, Lorena; Cruz, Jose M; Moldes, Ana B

    2015-08-19

    A decontamination technique based on the utilization of a lipopeptide biosurfactant extracted from corn steep liquor has been developed to eliminate polycyclic aromatic hydrocarbons (PAHs) from sewage sludge. High concentrations of PAHs were used during experiments observing that 408.3 mg/kg of naphthalene was almost completely mobilized and biodegraded, only 1.7% of naphthalene remained in the sewage sludge, whereas anthracene and pyrene were reduced up to 51.7 and 69.4%, respectively. The biodegradation of PAHs was fitted to several kinetic models (zero- and first-order kinetic models), observing good correlation coefficient values when biodegradation was described by the first-order kinetic model. Experimental results suggest that biosurfactant extracted from corn steep liquor may have great potential, as an ecofriendly washing agent, for the treatment of sewage sludge contaminated with PAHs. Therefore, in situ application of natural biosurfactants may be considered to be a good remediation alternative as they are not hazardous for water and soil organisms.

  3. Genome shuffling of Bacillus amyloliquefaciens for improving antimicrobial lipopeptide production and an analysis of relative gene expression using FQ RT-PCR.

    PubMed

    Zhao, Junfeng; Li, Yuanhong; Zhang, Chong; Yao, Zhengying; Zhang, Li; Bie, Xiaomei; Lu, Fengxia; Lu, Zhaoxin

    2012-06-01

    Genome shuffling is an efficient approach for the rapid improvement of the yield of secondary metabolites. This study was undertaken to enhance the yield of surfactin produced by Bacillus amyloliquefaciens ES-2-4 using genome shuffling and to examine changes in SrfA expression of the improved phenotype at the transcriptional level. Six strains with subtle improvements in lipopeptide yield were obtained from populations generated by ultraviolet irradiation, nitrosoguanidine, and ion beam mutagenesis. These strains were then subjected to recursive protoplast fusion. A strain library that was likely to yield positive colonies was created by fusing the lethal protoplasts obtained from both ultraviolet irradiation and heat treatments. After two rounds of genome shuffling, a high-yield recombinant F2-38 strain that exhibited 3.5- and 10.3-fold increases in surfactin production in shake flask and fermenter respectively, was obtained. Comparative analysis of synthetase gene expression was conducted between the initial and shuffled strains using FQ (fluorescent quantitation) RT-PCR. Delta CT (threshold cycle) relative quantitation analysis revealed that surfactin synthetase gene (srfA) expression at the transcriptional level in the F2-38 strain was 15.7-fold greater than in the ES-2-4 wild-type. The shuffled strain has a potential application in food and pharmaceutical industries. At the same time, the analysis of improved phenotypes will provide more valuable data for inverse metabolic engineering.

  4. Natural lipopeptide antibiotic tripropeptin C revitalizes and synergistically potentiates the activity of beta-lactams against methicillin-resistant Staphylococcus aureus.

    PubMed

    Hashizume, Hideki; Takahashi, Yoshiaki; Harada, Shigeko; Nomoto, Akio

    2015-06-01

    Tripropeptin C (TPPC) is a natural calcium-ion-dependent lipopeptide antibiotic that inhibits peptidoglycan biosynthesis by binding to prenyl pyrophosphate. It displays very potent antimicrobial activity both in vitro and in a mouse model of methicillin-resistant Staphylococcus aureus (MRSA) septicemia. The combination of TPPC with all classes of beta-lactams tested (including penam, carbapenem, cephem and oxacephem) showed highly synergistic (SYN) effects against MRSA strains, but not against methicillin-sensitive S. aureus strains. These SYN effects were observed with both a checkerboard methodology and a time-kill analysis. The TPPC analog, bis-methyl ester-TPPC, which has neither antimicrobial activity nor the ability to bind prenyl pyrophosphate, also potentiated the activity of beta-lactams. This result indicates that the mechanism of the SYN activity of TPPC is independent of its binding to prenyl pyrophosphate. Therefore, synergistically enhancing the anti-MRSA activities of TPPC and beta-lactams by combining them is a novel and potentially powerful therapeutic strategy for MRSA infections.

  5. Isolation and characterization of two new lipopeptide biosurfactants produced by Pseudomonas fluorescens BD5 isolated from water from the Arctic Archipelago of Svalbard.

    PubMed

    Janek, Tomasz; Łukaszewicz, Marcin; Rezanka, Tomas; Krasowska, Anna

    2010-08-01

    The arctic freshwater bacterium Pseudomonas fluorescens BD5 produces biosurfactants when grown on 2% glucose. Crude biosurfactants were extracted from a cell-free culture supernatant with ethyl acetate and purified by preparative reversed phase high performance liquid chromatography (RP-HPLC). The chemical structure of the purified biosurfactants, pseudofactin I and II, was analyzed by matrix assisted laser desorption/ionization time of flight (MALDI TOF) mass spectrometry and tandem mass spectrometry (MS/MS). Both compounds are novel cyclic lipopeptides with a palmitic acid connected to the terminal amino group of eighth amino acid in peptide moiety. The C-terminal carboxylic group of the last amino acid (Val or Leu) forms a lactone with the hydroxyl of Thr3. Pseudofactin II reduced the surface tension of water from 72 mN/m to 31.5 mN/m at a concentration of 72 mg/l. Its emulsification activity and stability was greater than that of the synthetic surfactants Tween 20 and Triton X-100; pseudofactins thus have a great potential for application in industrial fields such as bioremediation or biomedicine.

  6. Polyfunctional CD8(+) T cells are associated with the vaccination-induced control of a novel recombinant influenza virus expressing an HCV epitope.

    PubMed

    Tan, Amabel C L; Eriksson, Emily M Y; Kedzierska, Katherine; Deliyannis, Georgia; Valkenburg, Sophie A; Zeng, Weiguang; Jackson, David C

    2012-05-01

    In hepatitis C virus (HCV) infection, CD8(+) T cell responses have been shown to be important in viral clearance. Examining the efficacy of CD8(+) T cell vaccines against HCV has been limited by the lack of an HCV infectious model in mice and the differences between MHC restriction in humans and mice. Using HLA-A2 transgenic HHD mice, we demonstrate that intranasally delivered Pam2Cys-based lipopeptides containing HLA-A2-restricted HCV epitopes can induce polyfunctional CD8(+) T cell responses in several organs including the liver. To examine the activity of these responses in an infectious context, we developed a recombinant influenza virus that expresses the NS5B(2594-2602) epitope from non-structural protein 5B of hepatitis C virus (PR8-HCV(NS5B)). We showed that mice inoculated with a lipopeptide containing the NS5B epitope had reduced viral loads following challenge with the PR8-HCV(NS5B) virus. This reduction was associated with the induction of NS5B(2594-2602)-specific IFN-γ and TNF-α co-producing CD8(+) T cells. The T cell receptor usage in the NS5B(2594-2602) response was found to exhibit a Vβ8.1/8.2 bias that was characterized by a narrow repertoire and a common CDR3β motif. This work has identified CD8(+) T cell functions induced by lipopeptides that are associated with viral control and demonstrate the potential of lipopeptide-based vaccines as candidates for treatment of HCV infection.

  7. Inducibility of a molecular bioreporter system by heavy metals

    SciTech Connect

    Klimowski, L.; Rayms-Keller, A.; Olson, K.E.; Yang, R.S.H.; Tessari, J.; Carlson, J.; Beaty, B.

    1996-02-01

    The authors have developed a molecular bioreporter model for detecting an invertebrate response to heavy metals in streams. The bioreporter system, pMt2-luc, utilizes a Drosophila melanogaster metallothionein promoter to regulate luciferase expression in stably transformed mosquito cells.The LucC5 clone, which was isolated from pMt2-luc transformed, hygromycin-resistant C6/36 (Aedes albopictus) cells, demonstrated a 12-fold increase in luciferase-specific activity 48 h after exposure to 13 ppm copper (Cu). In addition to Cu, exposure of LucC5 cells to 19 ppm lead (Pb) or 3 ppm mercury (Hg) for 48 h induced luciferase expression threefold and fourfold, respectively. Exposures of up to 30 ppm arsenic (As), 8 ppm cadmium (Cd), 7 ppm chromium (Cr), or 5 ppm nickel (Ni) had no effect on luciferase induction. LucC5 cells exposed to metal mixtures of 13 ppm Cu and 19 ppm Pb yielded an additive response with a 14-fold increase in luciferase expression. When organic chemicals such as phenol (3 ppm) were mixed with 13 ppm Cu, 19 ppm Pb, or 3 ppm Hg a significant reduction in luciferase activity was noted. Additionally, atomic absorption spectroscopy suggested that two of the metals, Cu and Pb, show marked differences in accumulation within the LucC5 cell line.

  8. Methylglyoxal induces systemic symptoms of irritable bowel syndrome.

    PubMed

    Zhang, Shuang; Jiao, Taiwei; Chen, Yushuai; Gao, Nan; Zhang, Lili; Jiang, Min

    2014-01-01

    Patients with irritable bowel syndrome (IBS) show a wide range of symptoms including diarrhea, abdominal pain, changes in bowel habits, nausea, vomiting, headache, anxiety, depression and cognitive impairment. Methylglyoxal has been proved to be a potential toxic metabolite produced by intestinal bacteria. The present study was aimed at investigating the correlation between methylglyoxal and irritable bowel syndrome. Rats were treated with an enema infusion of methylglyoxal. Fecal water content, visceral sensitivity, behavioral tests and serum 5-hydroxytryptamine (5-HT) were assessed after methylglyoxal exposure. Our data showed that fecal water content was significantly higher than controls after methylglyoxal exposure except that of 30 mM group. Threshold volumes on balloon distension decreased in the treatment groups. All exposed rats showed obvious head scratching and grooming behavior and a decrease in sucrose preference. The serum 5-HT values were increased in 30, 60, 90 mM groups and decreased in 150 mM group. Our findings suggested that methylglyoxal could induce diarrhea, visceral hypersensitivity, headache as well as depression-like behaviors in rats, and might be the key role in triggering systemic symptoms of IBS.

  9. Methylglyoxal Induces Systemic Symptoms of Irritable Bowel Syndrome

    PubMed Central

    Zhang, Shuang; Jiao, Taiwei; Chen, Yushuai; Gao, Nan; Zhang, Lili; Jiang, Min

    2014-01-01

    Patients with irritable bowel syndrome (IBS) show a wide range of symptoms including diarrhea, abdominal pain, changes in bowel habits, nausea, vomiting, headache, anxiety, depression and cognitive impairment. Methylglyoxal has been proved to be a potential toxic metabolite produced by intestinal bacteria. The present study was aimed at investigating the correlation between methylglyoxal and irritable bowel syndrome. Rats were treated with an enema infusion of methylglyoxal. Fecal water content, visceral sensitivity, behavioral tests and serum 5-hydroxytryptamine (5-HT) were assessed after methylglyoxal exposure. Our data showed that fecal water content was significantly higher than controls after methylglyoxal exposure except that of 30 mM group. Threshold volumes on balloon distension decreased in the treatment groups. All exposed rats showed obvious head scratching and grooming behavior and a decrease in sucrose preference. The serum 5-HT values were increased in 30, 60, 90 mM groups and decreased in 150 mM group. Our findings suggested that methylglyoxal could induce diarrhea, visceral hypersensitivity, headache as well as depression-like behaviors in rats, and might be the key role in triggering systemic symptoms of IBS. PMID:25157984

  10. The rhizobacterial elicitor acetoin induces systemic resistance in Arabidopsis thaliana

    PubMed Central

    Rudrappa, Thimmaraju; Biedrzycki, Meredith L; Kunjeti, Sridhara G; Donofrio, Nicole M; Czymmek, Kirk J; Paré, Paul W

    2010-01-01

    The majority of plant growth promoting rhizobacteria (PGPR) confer plant immunity against a wide range of foliar diseases by activating plant defences that reduce a plant’s susceptibility to pathogen attack. Here we show that Arabidopsis thaliana (Col-0) plants exposed to Bacillus subtilis strain FB17 (hereafter FB17), results in reduced disease severity against Pseudomonas syringae pv. tomato DC3000 (hereafter DC3000) compared to plants without FB17 treatment. Exogenous application of the B. subtilis derived elicitor, acetoin (3-hydroxy-2-butanone), was found to trigger induced systemic resistance (ISR) and protect plants against DC3000 pathogenesis. Moreover, B. subtilis acetoin biosynthetic mutants that emitted reduced levels of acetoin conferred reduced protection to A. thaliana against pathogen infection. Further analysis using FB17 and defense-compromised mutants of A. thaliana indicated that resistance to DC3000 occurs via NPR1 and requires salicylic acid (SA)/ethylene (ET) whereas jasmonic acid (JA) is not essential. This study provides new insight into the role of rhizo-bacterial volatile components as elicitors of defense responses in plants. PMID:20585504

  11. A geomagnetically induced current warning system: model development and validation

    NASA Astrophysics Data System (ADS)

    McKay, A.; Clarke, E.; Reay, S.; Thomson, A.

    Geomagnetically Induced Currents (GIC), which can flow in technological systems at the Earth's surface, are a consequence of magnetic storms and Space Weather. A well-documented practical problem for the power transmission industry is that GIC can affect the lifetime and performance of transformers within the power grid. Operational mitigation is widely considered to be one of the best strategies to manage the Space Weather and GIC risk. Therefore in the UK a magnetic storm warning and GIC monitoring and analysis programme has been under development by the British Geological Survey and Scottish Power plc (the power grid operator for Central Scotland) since 1999. Under the auspices of the European Space Agency's service development activities BGS is developing the capability to meet two key user needs that have been identified. These needs are, firstly, the development of a near real-time solar wind shock/ geomagnetic storm warning, based on L1 solar wind data and, secondly, the development of an integrated surface geo-electric field and power grid network model that should allow prediction of GIC throughout the power grid in near real time. While the final goal is a `seamless package', the components of the package utilise diverse scientific techniques. We review progress to date with particular regard to the validation of the individual components of the package. The Scottish power grid response to the October 2003 magnetic storms is also discussed and model and validation data are presented.

  12. Leflunomide prevents ROS-induced systemic fibrosis in mice.

    PubMed

    Morin, Florence; Kavian, Niloufar; Chouzenoux, Sandrine; Cerles, Olivier; Nicco, Carole; Chéreau, Christiane; Batteux, Frédéric

    2017-03-30

    Systemic sclerosis (SSc) is a connective tissue disorder characterized by fibrosis of the skin and inner organs, vasculopathy and immunological abnormalities. Recent insights into the polarization of macrophages in scleroderma and into the implication of STAT6 and KLF4 in this process have prompted us to investigate the effects of the inhibition of STAT6 signaling pathway by leflunomide in mice. SSc was induced in BALB/c mice by daily subcutaneous injections of hypochlorous acid (HOCl) or bleomycin. Mice were treated (or not) every other day, for 4 or 6 weeks, by leflunomide. Skin and lung fibrosis as well as immunological features were studied. Mice exposed to HOCl developed a diffuse cutaneous SSc with pulmonary fibrosis and anti-DNA topoisomerase 1 auto-antibodies. STAT6 pathway was hyperactivated and KLF4 was overexpressed in the skin and the lungs of diseased mice. Their inhibition by leflunomide prevented skin and lung fibrosis. Moreover, the hyperproliferative and pro-oxidative phenotype of skin and lung fibroblasts was reversed by leflunomide. Beneficial immunological effects of leflunomide were associated with decreased activation of CD4+ and CD8+ T cells, B cell activation, decreased auto-antibodies production and restored polarization of macrophages in the spleen. The improvement provided by leflunomide in both mouse models of SSc provides a rationale for the evaluation of this immunomodulating drug in the management of patients affected by this disease.

  13. Acrolein consumption induces systemic dyslipidemia and lipoprotein modification

    SciTech Connect

    Conklin, Daniel J.; Barski, Oleg A.; Lesgards, Jean-Francois; Juvan, Peter; Rezen, Tadeja; Rozman, Damjana; Prough, Russell A.; Vladykovskaya, Elena; Liu, SiQi; Srivastava, Sanjay; Bhatnagar, Aruni

    2010-02-15

    Aldehydes such as acrolein are ubiquitous pollutants present in automobile exhaust, cigarette, wood, and coal smoke. Such aldehydes are also constituents of several food substances and are present in drinking water, irrigation canals, and effluents from manufacturing plants. Oral intake represents the most significant source of exposure to acrolein and related aldehydes. To study the effects of short-term oral exposure to acrolein on lipoprotein levels and metabolism, adult mice were gavage-fed 0.1 to 5 mg acrolein/kg bwt and changes in plasma lipoproteins were assessed. Changes in hepatic gene expression related to lipid metabolism and cytokines were examined by qRT-PCR analysis. Acrolein feeding did not affect body weight, blood urea nitrogen, plasma creatinine, electrolytes, cytokines or liver enzymes, but increased plasma cholesterol and triglycerides. Similar results were obtained with apoE-null mice. Plasma lipoproteins from acrolein-fed mice showed altered electrophoretic mobility on agarose gels. Chromatographic analysis revealed elevated VLDL cholesterol, phospholipids, and triglycerides levels with little change in LDL or HDL. NMR analysis indicated shifts from small to large VLDL and from large to medium-small LDL with no change in the size of HDL particles. Increased plasma VLDL was associated with a significant decrease in post-heparin plasma hepatic lipase activity and a decrease in hepatic expression of hepatic lipase. These observations suggest that oral exposure to acrolein could induce or exacerbate systemic dyslipidemia and thereby contribute to cardiovascular disease risk.

  14. Acrolein Consumption Induces Systemic Dyslipidemia and Lipoprotein Modification

    PubMed Central

    Conklin, Daniel J.; Barski, Oleg A.; Lesgards, Jean-Francois; Juvan, Peter; Rezen, Tadeja; Rozman, Damjana; Prough, Russell A.; Vladykovskaya, Elena; Liu, SiQi; Srivastava, Sanjay; Bhatnagar, Aruni

    2010-01-01

    Aldehydes such as acrolein are ubiquitous pollutants present in automobile exhaust, cigarette, wood, and coal smoke. Such aldehydes are also constituents of several food substances and are present in drinking water, irrigation canals, and effluents from manufacturing plants. Oral intake represents the most significant source of exposure to acrolein and related aldehydes. To study the effects of short-term oral exposure to acrolein on lipoprotein levels and metabolism, adult mice were gavage fed 0.1 to 5 mg acrolein/kg bwt and changes in plasma lipoproteins were assessed. Changes in hepatic gene expression related to lipid metabolism and cytokines were examined by qRT-PCR analysis. Acrolein feeding did not affect body weight, BUN, plasma creatinine, electrolytes, cytokines or liver enzymes, but increased plasma cholesterol and triglycerides. Similar results were obtained with apoE-null mice. Plasma lipoproteins from acrolein-fed mice showed altered electrophoretic mobility on agarose gels. Chromatographic analysis revealed elevated VLDL cholesterol, phospholipids, and triglycerides levels with little change in LDL or HDL. NMR analysis indicated shifts from small to large VLDL and from large to medium-small LDL with no change in the size of HDL particles. Increased plasma VLDL was associated with a significant decrease in post-heparin plasma hepatic lipase activity and a decrease in hepatic expression of hepatic lipase. These observations suggest that oral exposure to acrolein could induce or exacerbate systemic dyslipidemia and thereby contribute to cardiovascular disease risk. PMID:20034506

  15. Phase Jumps in an Electro-magnetically Induced Transparency System

    NASA Astrophysics Data System (ADS)

    Narducci, F. A.; Noble, J.; Welch, G. R.; Davis, J. P.

    2010-03-01

    We have taken a closer look at the dynamics of an EIT system when the relative phase of the two lasers is abruptly changed. The absorption of the probe field rapidly increases to a value that can exceed even the ordinary two-level absorption, then slowly decays back down to the induced transparency level. This system has been previously studied by some of us theoretically [1] and experimentally [2,3]. We show that the timescale for the rapid rise is set by the inverse bandwidth of the medium in the absence of the pump field and is therefore dramatically different for a room temperature cell as for a laser cooled sample. We also show that, surprisingly, the slow decay is not dependent on the ground state coherence time, but rather, the interplay between the Rabi frequencies and the excited state spontaneous emission rate. This suggests that, theoretically, the rise time can be made arbitrarily fast, while, simultaneously, the decay time can be made arbitrarily small or even zero. We draw a comparison with experiments performed in a warm cell and in experiments being conducted in a cold sample of atoms. [1] T. Abi-salloum, J.P. Davis, C. Lehman, E. Elliott, F.A. Narducci, J. Mod. Opt, 54, 2459-2471, (2007). [2] V.A. Sautenkov, H. Li, Y.V. Rostovtsev, G.R. Welch, J.P. Davis, F.A. Narducci, M. O. Scully, J. Mod. Opt, 55, 3093-3099, (2008). [3] V.A. Sautenkov, H. Li, Y.V. Rostovtsev, G.R. Welch, J.P. Davis, F.A. Narducci, M.O. Scully, J. Mod. Opt, 56, 975-979, (2009).

  16. Rapid laser induced energy transfer in atomic systems

    NASA Technical Reports Server (NTRS)

    Harris, S. E.; Young, J. F.

    1978-01-01

    Analytical and experimental studies of the rapid transfer of stored populations from metastable states to selected target states of a different species are reported. Both laser-induced or laser-switched collision and laser-induced two-photon spontaneous emission are described. It is shown that the laser-induced collision method is particularly useful in the visible and UV spectral regions. It has applications in photochemistry, gas-phase kinetics, and in high-power, high-energy gas-phase lasers. The anti-Stokes source is useful in the VUV and soft X-ray spectral regions.

  17. Protocol for Addressing Induced Seismicity Associated with Enhanced Geothermal Systems

    SciTech Connect

    Majer, Ernie; Nelson, James; Robertson-Tait, Ann; Savy, Jean; Wong, Ivan

    2012-01-01

    This Protocol is a living guidance document for geothermal developers, public officials, regulators and the general public that provides a set of general guidelines detailing useful steps to evaluate and manage the effects of induced seismicity related to EGS projects.

  18. A novel cold-inducible expression system for Bacillus subtilis.

    PubMed

    Thuy Le, Ai Thi; Schumann, Wolfgang

    2007-06-01

    Production of recombinant proteins at low temperatures is one strategy to prevent formation of protein aggregates and the use of an expensive inducer such as IPTG. We report on the construction of two expression vectors both containing the cold-inducible des promoter of Bacillus subtilis, where one allows intra- and the other extracellular synthesis of recombinant proteins. Production of recombinant proteins started within the first 30min after temperature downshock to 25 degrees C and continued for about 5h.

  19. Inducible and constitutive promoters for genetic systems in Sulfolobus acidocaldarius.

    PubMed

    Berkner, Silvia; Wlodkowski, Alexander; Albers, Sonja-Verena; Lipps, Georg

    2010-05-01

    Central to genetic work in any organism are the availability of a range of inducible and constitutive promoters. In this work we studied several promoters for use in the hyperthermophilic archaeon Sulfolobus acidocaldarius. The promoters were tested with the aid of an E. coli-Sulfolobus shuttle vector in reporter gene experiments. As the most suitable inducible promoter a maltose inducible promoter was identified. It comprises 266 bp of the sequence upstream of the gene coding for the maltose/maltotriose binding protein (mbp, Saci_1165). Induction is feasible with either maltose or dextrin at concentrations of 0.2-0.4%. The highest increase in expression (up to 17-fold) was observed in late exponential and stationary phase around 30-50 h after addition of dextrin. Whereas in the presence of glucose and xylose higher basal activity and reduced inducibility with maltose is observed, sucrose can be used in the growth medium additionally without affecting the basal activity or the inducibility. The minimal promoter region necessary could be narrowed down to 169 bp of the upstream sequence. The ABCE1 protein from S. solfataricus was successfully expressed under control of the inducible promoter with the shuttle vector pC and purified from the S. acidocaldarius culture with a yield of about 1 mg L(-1) culture. In addition we also determined the promoter strength of several constitutive promoters.

  20. Model system for investigating laser-induced subcellular microeffects

    NASA Astrophysics Data System (ADS)

    Huettmann, Gereon; Serbin, Jesper; Radt, Benno; Lange, Bjoern I.; Birngruber, Reginald

    2001-07-01

    Background: Laser induced protein denaturation is of fundamental interest for understanding the mechanisms of laser tissue interaction. Conjugates of nanoabsorbers coupled to proteins are presented as a model system for investigating ultrafast protein denaturation. Irradiation of the conjugates using repetitive picosecond laser pulses, which are only absorbed by the nanoabsorbers, could result in effects with a spatial confinement of less than 100 nm. Materials and Methods: Experiments were done with bovine intestinal alkaline phosphates (aP) coupled to 15 nm colloidal gold. This complex was irradiated at 527 nm wavelength and 35 ps pulse width with a varying number of pulses ranging form one up to 104. The radiant exposure per pulse was varied form 2 mJ/cm2 to 50 mJ/cm2. Denaturation was detected as a loss of protein function with the help of the fluorescence substrate 4MUP. Results and discussion: Irradiation did result in a steady decrease of the aP activity with increasing radiant exposures and increasing number of pulses. A maximal inactivation of 80% was reached with 104 pulses and 50 mJ/cm2 per pulse. The temperature in the particles and the surrounding water was calculated using Mie's formulas for the absorption of the nanometer gold particles and ana analytical solution of the equations for heat diffusion. With 50 mJ/cm2, the particles are heated above the melting point of gold. Since the temperature calculations strongly depend on changes in the state of matter of the particles and water, a very sophisticated thermal model is necessary to calculate exact temperatures. It is difficult to identify one of the possible mechanisms, thermal denaturation, photochemical denaturation or formation of micro bubbles from the dependance of the inactivation on pulse energy and number of applied pulses. Therefore, experiments are needed to further elucidate the damage mechanisms. In conclusion, denaturing proteins irreversibly via nanoabsorbers using picosecond laser

  1. Effect of Surotomycin, a Novel Cyclic Lipopeptide Antibiotic, on Intestinal Colonization with Vancomycin-Resistant Enterococci and Klebsiella pneumoniae in Mice.

    PubMed

    Deshpande, Abhishek; Hurless, Kelly; Cadnum, Jennifer L; Chesnel, Laurent; Gao, Lihong; Chan, Luisa; Kundrapu, Sirisha; Polinkovsky, Alexander; Donskey, Curtis J

    2016-06-01

    Surotomycin (formerly called CB-183,315) is a novel, orally administered cyclic lipopeptide antibacterial in development for the treatment of Clostridium difficile infection (CDI) that has potent activity against vancomycin-resistant enterococci (VRE) but limited activity against Gram-negative bacilli, including Bacteroides spp. We used a mouse model to investigate the impact of surotomycin exposure on the microbiome, and to test the consequences of the disruption on colonization by vancomycin-resistant enterococci (VRE) and extended-spectrum β-lactamase-producing Klebsiella pneumoniae (ESBL-KP), in comparison with the effects of oral vancomycin and metronidazole. Mice (8 per group) received saline, vancomycin, metronidazole, or surotomycin through an orogastric tube daily for 5 days and were challenged with 10(5) CFU of VRE or ESBL-KP administered through an orogastric tube on day 2 of treatment. The concentrations of the pathogens in stool were determined during and after treatment by plating on selective media. A second experiment was conducted to determine if the antibiotics would inhibit established VRE colonization. In comparison to controls, oral vancomycin promoted VRE and ESBL-KP overgrowth in stool (8 log10 to 10 log10 CFU/g; P < 0.001), whereas metronidazole did not (<4 log10 CFU/g; P > 0.5). Surotomycin promoted ESBL-KP overgrowth (>8 log10 CFU/g; P, <0.001 for comparison with saline controls) but not VRE overgrowth. Surotomycin suppressed preexisting VRE colonization, whereas metronidazole and vancomycin did not. These results suggest that treatment of CDI with surotomycin could reduce levels of VRE acquisition and overgrowth from those with agents such as vancomycin and metronidazole. However, surotomycin and vancomycin may promote colonization by antibiotic-resistant Gram-negative bacilli.

  2. Battacin (Octapeptin B5), a New Cyclic Lipopeptide Antibiotic from Paenibacillus tianmuensis Active against Multidrug-Resistant Gram-Negative Bacteria

    PubMed Central

    Qian, Chao-Dong; Teng, Yi; Zhao, Wen-Peng; Li, Ou; Fang, Sheng-Guo; Huang, Zhao-Hui; Gao, Hai-Chun

    2012-01-01

    Hospital-acquired infections caused by drug-resistant bacteria are a significant challenge to patient safety. Numerous clinical isolates resistant to almost all commercially available antibiotics have emerged. Thus, novel antimicrobial agents, specifically those for multidrug-resistant Gram-negative bacteria, are urgently needed. In the current study, we report the isolation, structure elucidation, and preliminary biological characterization of a new cationic lipopeptide antibiotic, battacin or octapeptin B5, produced from a Paenibacillus tianmuensis soil isolate. Battacin kills bacteria in vitro and has potent activity against Gram-negative bacteria, including multidrug-resistant and extremely drug-resistant clinical isolates. Hospital strains of Escherichia coli and Pseudomonas aeruginosa are the pathogens most sensitive to battacin, with MICs of 2 to 4 μg/ml. The ability of battacin to disrupt the outer membrane of Gram-negative bacteria is comparable to that of polymyxin B, the last-line therapy for infections caused by antibiotic-resistant Gram-negative bacteria. However, the capacity of battacin to permeate bacterial plasma membranes is less extensive than that of polymyxin B. The bactericidal kinetics of battacin correlate with the depolarization of the cell membrane, suggesting that battacin kills bacteria by disrupting the cytoplasmic membrane. Other studies indicate that battacin is less acutely toxic than polymyxin B and has potent in vivo biological activity against E. coli. Based on the findings of the current study, battacin may be considered a potential therapeutic agent for the treatment of infections caused by antibiotic-resistant Gram-negative bacteria. PMID:22183171

  3. Loss of GltB Inhibits Biofilm Formation and Biocontrol Efficiency of Bacillus subtilis Bs916 by Altering the Production of γ-Polyglutamate and Three Lipopeptides

    PubMed Central

    Luo, Chuping; Fang, Xianwen; Xiang, Yaping; Wang, Xiaoyu; Zhang, Rongsheng; Chen, Zhiyi

    2016-01-01

    Aims This study examined the contribution of GltB on biofilm formation and biocontrol efficiency of B. subtilis Bs916. Methods and Results The gltB gene was identified through a biofilm phenotype screen and a bioinformatics analysis of serious biofilm formation defects, and then a gltB single knockout mutant was constructed using homologous recombination. This mutant demonstrated severe deficits in biofilm formation and colonisation along with significantly altered production ofγ-polyglutamate (γ-PGA) and three lipopeptide antibiotics (LPs) as measured by a transcriptional analysis of both the wild type B. subtilis Bs916 and the gltB mutant. Consequently, the mutant strain retained almost no antifungal activity against Rhizoctonia solani and exhibited decreased biocontrol efficiency against rice sheath blight. Very few gltB mutant cells colonised the rice stem, and they exhibited no significant nutrient chemotaxis compared to the wild type B. subtilis Bs916. The mechanism underlying these deficits in the gltB mutant appears to be decreased significantly in production of γ-PGA and a reduction in the production of both bacillomycin L and fengycin. Biofilm restoration of gltB mutant by additionγ-PGA in the EM medium demonstrated that biofilm formation was able to restore significantly at 20 g/L. Conclusions GltB regulates biofilm formation by altering the production ofγ-PGA, the LPs bacillomycin L and fengcin and influences bacterial colonisation on the rice stem, which consequently leads to poor biocontrol efficiency against rice sheath blight. Significance and Impact of Study This is the first report of a key regulatory protein (GltB) that is involved in biofilm regulation and its regulation mechanism and biocontrol efficiency by B. subtilis. PMID:27223617

  4. Acute Ozone-Induced Pulmonary and Systemic Metabolic ...

    EPA Pesticide Factsheets

    Acute ozone exposure increases circulating stress hormones and induces metabolic alterations in animals and humans. We hypothesized that the increase of adrenal-derived stress hormones is necessary for both ozone-induced metabolic effects and lung injury. Male Wistar-Kyoto rats underwent adrenal demedullation (DEMED), total bilateral adrenalectomy (ADREX), or sham surgery (SHAM). After a 4 day recovery, rats were exposed to air or ozone (1ppm), 4h/day for 1 or 2 days. Circulating adrenaline levels dropped to nearly zero in DEMED and ADREX rats relative to air-exposed SHAM. Corticosterone levels tended to be low in DEMED rats and dropped to nearly zero in ADREX rats. Adrenalectomy in air-exposed rats caused modest changes in metabolites and lung toxicity parameters. Ozone-induced hyperglycemia and glucose intolerance were markedly attenuated in DEMED rats with nearly complete reversal in ADREX rats. Ozone increased circulating epinephrine and corticosterone in SHAM but not in DEMED or ADREX rats. Free fatty acids (p=0.15) and branched-chain amino acids increased after ozone exposure in SHAM but not in DEMED or ADREX rats. Lung minute volume was not affected by surgery or ozone but ozone-induced labored breathing was less pronounced in ADREX rats. Ozone-induced increases in lung protein leakage and neutrophilic inflammation were markedly reduced in DEMED and ADREX rats (ADREX>DMED). Ozone-mediated decreases in circulating white blood cells in SHAM were not obser

  5. [Zinc- and tin-induced apoptotic mechanisms in immune system and cranial nerve system].

    PubMed

    Tomiyama, Kenichi; Arakawa, Yasuaki

    2016-07-01

    This review explains the mechanisms of apoptosis related to the impacts of zinc deficiency and organotin exposure on the immune and central nervous systems. In the immune systems, both zinc deficiency and trialkyltin exposure lead to severe thymic atrophy and affect T-lymphocyte development through apoptosis of double positive stage pre-T-cells(CD4+/CD8+) in the cortex region. Their apoptosis are caused mainly through decrease in Bcl-2 expression, activation of ROS production/release, oxidative stress, mitochondrial cytochrome c release and activation of caspase cascade, with increases in glucocorticoids in zinc deficiency, without the involvement of glucocorticoid in organotin exposure In the central nervous system, both zinc deficiency and trialkyltin exposure reduce learning, memory and sensory functions through neuronal apoptosis caused by activation of ROS production/release, release of pro-apoptotic factors such as cytochrome c or apoptosis-inducing factor(AIF), with Fe excessive accumulation leading to ROS production and with depletion of hippocampus Zn (mossy fiber Zn) causing various Ca2+ channel disorder of synapse in the hippocampus, and with excessive accumulation of Ca through cAMP-dependent Ca(2+)-channel disorder by excessive PTH and cAMP excessive production in the olfactory systems such as olfactory epithelium and olfactory bulb.

  6. [Neuroprotective effects of semax in MPTP-induced disturbances of brain dopamine system].

    PubMed

    Levitskaia, N G; Sebentsova, E A; Andreeva, L A; Alfeeva, L Iu; Kamenskiĭ, A A; Miasoedov, N F

    2002-11-01

    Effects of an ACTH (4-10) analogue Semax (MEHFPGP) on behaviour of white rats with MPTP-induced disturbances of brain DA-system have been studied. It was shown that MPTP administration (25 mg/kg) reduced motor activity and auhmented the anxiety level in rats. Semax administration (daily intranasal 0.2 mg/kg) attenuated behaviour disturbances induced by neurotoxin. The observed protective action of Semax in rats with MFTP-induced DA system disturbances may be due to both its modulating influence on the brain DA system and peptide neuroprotective effects.

  7. Optomechanically induced transparency and absorption in hybridized optomechanical systems

    NASA Astrophysics Data System (ADS)

    Hou, B. P.; Wei, L. F.; Wang, S. J.

    2015-09-01

    We present the normal-mode splitting and optomechanically induced transparency or absorption phenomena in the strongly tunnel-coupled optomechanical cavities. In the probe output spectrum, there appear central transparency windows or absorption peaks around which two broad sidebands are symmetrically located. It has been confirmed by the quantitative findings that two broad sidebands, which include the distorted absorption peaks, indicate the normal-mode splitting of the two hybridized cavities, and central transparency windows or absorption peaks character the interference induced by the optomechanical interactions. Additionally, the switching from absorption to amplification can be realized by only adjusting the tunnel interaction. These spectrum properties can be used for the coherent control of light pulses via microfabricated optomechanical arrays.

  8. [Research of antioxidant defence system under alimentary induced oxidative stress].

    PubMed

    Kravchenko, Iu V; Mal'tsev, G Iu; Vasil'ev, A V

    2004-01-01

    Alimentary induced oxidative stress and its corrections in children and adults with homocysteine metabolism disorder are urgent problems for arteriosclerosis and cardiovascular disease prophylactics. For determination antioxidant status GSH-Px, SOD, GSH-reductase, catalase activities were detected. Effectiveness of Se-contained antioxidant complex "Selenec" was determined in experimental model with pubertal male Wistar rats. Including high value of methionine to semipurified diet with pyridoxine and folate deficiency induced oxidative stress. Lipid peroxidation substances were increased in blood, liver, intestine mucous tunic, aortal endothelium and myocardium. GSH-Px, SOD, GSH-reductase, catalase activities decreased significant compared to control. "Selenec" supplementation caused a decrease of thiobarbituric-reactive substances level, increasing SOD and catalase activity and decreasing GSH-Px and GSH-reductase activity in blood, liver, intestine mucous tunic, aorta and myocardium.

  9. Stress-induced obesity and the emotional nervous system.

    PubMed

    Dallman, Mary F

    2010-03-01

    Stress and emotional brain networks foster eating behaviors that can lead to obesity. The neural networks underlying the complex interactions among stressors, body, brain and food intake are now better understood. Stressors, by activating a neural stress-response network, bias cognition toward increased emotional activity and degraded executive function. This causes formed habits to be used rather than a cognitive appraisal of responses. Stress also induces secretion of glucocorticoids, which increases motivation for food, and insulin, which promotes food intake and obesity. Pleasurable feeding then reduces activity in the stress-response network, reinforcing the feeding habit. These effects of stressors emphasize the importance of teaching mental reappraisal techniques to restore responses from habitual to thoughtful, thus battling stress-induced obesity.

  10. Acute Ozone-Induced Pulmonary and Systemic Metabolic Effects are Diminished in Adrenalectomized Rats

    EPA Science Inventory

    Acute ozone exposure increases circulating stress hormones and induces peripheral metabolic alterations in animals and humans. We hypothesized that the increase of adrenal-derived stress hormones is necessary for ozone-induced systemic metabolic effects and lung injury. Male Wis...

  11. The highly efficient sex-inducing pheromone system of Volvox.

    PubMed

    Hallmann, A; Godl, K; Wenzl, S; Sumper, M

    1998-05-01

    The green alga Volvox is one of the simplest multicellular organisms and is capable of both asexual and sexual reproduction. Sexual development is initiated by a glycoprotein pheromone that acts at a concentration below 10(-16) M. The extracellular matrix (ECM) appears to play a key role in signal amplification: several ECM proteins contain a domain with homology to the sex-inducing pheromone.

  12. LOVTRAP, An Optogenetic System for Photo-induced Protein Dissociation

    PubMed Central

    Wang, Hui; Vilela, Marco; Winkler, Andreas; Tarnawski, Miroslaw; Schlichting, Ilme; Yumerefendi, Hayretin; Kuhlman, Brian; Liu, Rihe; Danuser, Gaudenz; Hahn, Klaus M

    2016-01-01

    Here we introduce LOVTRAP, an optogenetic approach for reversible, light-induced protein dissociation. LOVTRAP is based on protein A fragments that bind to the LOV domain only in the dark, with tunable kinetics and a >150-fold change in Kd. By reversibly sequestering proteins at mitochondria, we precisely modulated the proteins’ access to the cell edge, demonstrating a naturally occurring 3 mHz cell edge oscillation driven by interactions of Vav2, Rac1 and PI3K. PMID:27427858

  13. Development and application of an arabinose-inducible expression system by facilitating inducer uptake in Corynebacterium glutamicum.

    PubMed

    Zhang, Yun; Shang, Xiuling; Lai, Shujuan; Zhang, Guoqiang; Liang, Yong; Wen, Tingyi

    2012-08-01

    Corynebacterium glutamicum is currently used for the industrial production of a variety of biological materials. Many available inducible expression systems in this species use lac-derived promoters from Escherichia coli that exhibit much lower levels of inducible expression and leaky basal expression. We developed an arabinose-inducible expression system that contains the L-arabinose regulator AraC, the P(BAD) promoter from the araBAD operon, and the L-arabinose transporter AraE, all of which are derived from E. coli. The level of inducible P(BAD)-based expression could be modulated over a wide concentration range from 0.001 to 0.4% L-arabinose. This system tightly controlled the expression of the uracil phosphoribosyltransferase without leaky expression. When the gene encoding green fluorescent protein (GFP) was under the control of P(BAD) promoter, flow cytometry analysis showed that GFP was expressed in a highly homogeneous profile throughout the cell population. In contrast to the case in E. coli, P(BAD) induction was not significantly affected in the presence of different carbon sources in C. glutamicum, which makes it useful in fermentation applications. We used this system to regulate the expression of the odhI gene from C. glutamicum, which encodes an inhibitor of α-oxoglutarate dehydrogenase, resulting in high levels of glutamate production (up to 13.7 mM) under biotin nonlimiting conditions. This system provides an efficient tool available for molecular biology and metabolic engineering of C. glutamicum.

  14. Hyperfiltration-induced fractionation of lithium isotopes in geologic systems

    SciTech Connect

    Fritz, S.J.

    1991-01-01

    Hyperfiltration through clay membranes induces isotopic fractionation in which a solute's heavy isotope is depleted on the clay membrane's high-pressure side. It should be thus possible to delineate regions of high and low hydrostatic heads in the subsurface by plotting distributions of elements' isotopic ratios obtained through analyses of samples collected from opposing sides of aquitards. High degrees of hyperfiltration-induced fractionation should result when ions of a low atomic-weight element are hydraulically forced through a highly ideal clay membrane. This study gauges the magnitude of {sup 7}Li/{sup 6}Li fractionation during hyperfiltration through clay membranes. The results will yield baseline data against which hyperfiltration-induced isotopic fractionation of higher atomic-weight elements should be compared in future hydrogeochemical investigations. The following tasks were accomplished since April 1, 1990: (1) fabrication of the testing apparatus began, with estimated completion by March of 1991; (2) beneficiation of 450 grams of freeze-dried clay; (3) analytical standardization of {sup 7}LiCl and {sup 6}LiCl stock solutions; and (4) an experiment conducted on dialysis tubing testing the isotopic fractionation of Li isotopes during the evolution of an osmotic cell. Analytical measurements of the {sup 7}Li/{sup 6}Li ratios from this experiment have not yet been performed. 2 figs.

  15. Persistent high fever and systemic inflammation induced by percutaneous coronary intervention-related periaortitis

    PubMed Central

    Kakino, Takamori; Nakayama, Tomohiro; Yamamoto, Hideo

    2009-01-01

    After coronary catheterization, fever sometimes occurs, usually transiently. We report a very rare case that suggests persistent high fever and systemic inflammation might be caused by periaortitis induced by coronary catheterization including percutaneous coronary intervention. PMID:20057898

  16. Remarks on Generalized Uncertainty Principle Induced from Constraint System

    NASA Astrophysics Data System (ADS)

    Eune, Myungseok; Kim, Wontae

    2014-12-01

    The extended commutation relations for generalized uncertainty principle (GUP) have been based on the assumption of the minimal length in position. Instead of this assumption, we start with a constrained Hamiltonian system described by the conventional Poisson algebra and then impose appropriate second class constraints to this system. Consequently, we can show that the consistent Dirac brackets for this system are nothing, but the extended commutation relations describing the GUP.

  17. Liposomally encapsulated diclofenac for sonophoresis induced systemic delivery.

    PubMed

    Vyas, S P; Singh, R; Asati, R K

    1995-01-01

    Liposomes containing diclofenac, an anti-inflammatory agent were incorporated into an ointment base for topical application. The drug loaded liposomes were characterized for various physico-chemical attributes and drug efflux profile in in vitro. The systemic availability of drug from liposomes following topical application was evaluated in rats. The effect of sonophoresis on the drug release profile in vitro and systemic availability in vivo was established. The application of liposomal diclofenac resulted in localization of the drug at the site of application with slow systemic availability; however, with the application of ultrasound pulsed drug systemic levels could be achieved.

  18. Effects of System Dynamics on Friction-Induced Oscillations

    NASA Astrophysics Data System (ADS)

    Swayze, J. L.; Akay, A.

    1994-06-01

    In many mechanical systems, friction is the primary source of oscillations, often leading to unstable behavior of system components. In some cases, it is the non-linear nature of the friction force that causes a non-linear response of the system. In others, however, regardless of the type of friction force, the coupling between the modes of a system can be the primary reason for its non-linear behavior. In this paper, a simple model is given to demonstrate the stability characteristics of a mass with two degrees of freedom, excited by a steady friction force. The mass is compressed against a frictional surface by a combination of linear and torsional springs, similar to a brush held against a commutator in electric motors. System equations are developed using a constant friction coefficient. Results are obtained by observing the motion of the mass in the phase space.

  19. Inducible Expression of CXCL1 within the Central Nervous System Amplifies Viral-Induced Demyelination

    PubMed Central

    Marro, Brett S.; Grist, Jonathan J.

    2016-01-01

    The functional role of the ELR+ chemokine CXCL1 in host defense and disease following infection of the CNS with the neurotropic JHM strain of mouse hepatitis virus (JHMV) was examined. Mice in which expression of CXCL1 is under the control of a tetracycline-inducible promoter active within glial fibrillary acidic protein–positive cells were generated and this allowed for selectively increasing CNS expression of CXCL1 in response to JHMV infection and evaluating the effects on neuroinflammation, control of viral replication, and demyelination. Inducible expression of CNS-derived CXCL1 resulted in increased levels of CXCL1 protein within the serum, brain, and spinal cord that correlated with increased frequency of Ly6G+CD11b+ neutrophils present within the CNS. Elevated levels of CXCL1 did not influence the generation of virus-specific T cells, and there was no difference in control of JHMV replication compared with control mice, indicating that T cell infiltration into the CNS is CXCL1-independent. Sustained CXCL1 expression within the CNS resulted in increased mortality that correlated with elevated neutrophil infiltration, diminished numbers of mature oligodendrocytes, and an increase in the severity of demyelination. Neutrophil ablation in CXCL1-transgenic mice reduced the severity of demyelination in mice, arguing for a role for these cells in white matter damage. Collectively, these findings illustrate that sustained CXCL1 expression amplifies the severity of white matter damage and that neutrophils can contribute to this process in a model of viral-induced neurologic disease. PMID:26773148

  20. Complex nanoprecipitate structures induced by irradiation in immiscible alloy systems

    NASA Astrophysics Data System (ADS)

    Shu, Shipeng; Bellon, P.; Averback, R. S.

    2013-04-01

    We investigate the fundamentals of compositional patterning induced by energetic particle irradiation in model A-B substitutional binary alloys using kinetic Monte Carlo simulations. The study focuses on a type of nanostructure that was recently observed in dilute Cu-Fe and Cu-V alloys, where precipitates form within precipitates, a morphology that we term “cherry-pit” structures. The simulations show that the domain of stability of these cherry-pit structures depends on the thermodynamic and kinetic asymmetry between the A and B elements. In particular, both lower solubilities and diffusivities of A in B compared to those of B in A favor the stabilization of these cherry-pit structures for A-rich average compositions. The simulation results are rationalized by extending the analytic model introduced by Frost and Russell for irradiation-induced compositional patterning so as to include the possible formation of pits within precipitates. The simulations indicate also that the pits are dynamical structures that undergo nearly periodic cycles of nucleation, growth, and absorption by the matrix.

  1. Tet-On Systems For Doxycycline-inducible Gene Expression

    PubMed Central

    Das, Atze T.; Tenenbaum, Liliane; Berkhout, Ben

    2016-01-01

    The tetracycline-controlled Tet-Off and Tet-On gene expression systems are used to regulate the activity of genes in eukaryotic cells in diverse settings, varying from basic biological research to biotechnology and gene therapy applications. These systems are based on regulatory elements that control the activity of the tetracycline-resistance operon in bacteria. The Tet-Off system allows silencing of gene expression by administration of tetracycline (Tc) or tetracycline-derivatives like doxycycline (dox), whereas the Tet-On system allows activation of gene expression by dox. Since the initial design and construction of the original Tet-system, these bacterium-derived systems have been significantly improved for their function in eukaryotic cells. We here review how a dox-controlled HIV-1 variant was designed and used to greatly improve the activity and dox-sensitivity of the rtTA transcriptional activator component of the Tet-On system. These optimized rtTA variants require less dox for activation, which will reduce side effects and allow gene control in tissues where a relatively low dox level can be reached, such as the brain. PMID:27216914

  2. Noise-induced striped trajectories of Rossler systems

    NASA Astrophysics Data System (ADS)

    Huang, Zhi-Hua; Dong, Ya-Li

    2007-08-01

    In this paper, the generation of striped trajectories in phase space by noise-injection is considered. With suitable amplitudes of noise, the steady-state system orbits appear in rectangular striped shape. The relationship between the shape (including the range and the number of stripes) and some parameters is discussed. The result shows that noise can also generate the striped shape effectively and simply, which is similar to the newly-discovered striped pattern generated by controlled Rossler systems.

  3. Asymmetry-induced electric current rectification in permselective systems

    NASA Astrophysics Data System (ADS)

    Green, Yoav; Edri, Yaron; Yossifon, Gilad

    2015-09-01

    For a symmetric ion permselective system, in terms of geometry and bulk concentrations, the system response is also symmetric under opposite electric field polarity. In this work we derive an analytical solution for the concentration distribution, electric potential, and current-voltage response for a four-layered system comprised of two microchambers connected by two permselective regions of varying properties. It is shown that any additional asymmetry in the system, in terms of the geometry, bulk concentration, or surface charge property of the permselective regions, results in current rectification. Our work is divided into two parts: when both permselective regions have the same surface charge sign and the case of opposite signs. For the same sign case we are able to show that the system behaves as a dialytic battery while accounting for field-focusing effects. For the case of opposite signs (i.e., bipolar membrane), our system exhibits the behavior of a bipolar diode where the magnitude of the rectification can be of order 102-103 .

  4. An expert system for diagnosing environmentally induced spacecraft anomalies

    NASA Technical Reports Server (NTRS)

    Rolincik, Mark; Lauriente, Michael; Koons, Harry C.; Gorney, David

    1992-01-01

    A new rule-based, machine independent analytical tool was designed for diagnosing spacecraft anomalies using an expert system. Expert systems provide an effective method for saving knowledge, allow computers to sift through large amounts of data pinpointing significant parts, and most importantly, use heuristics in addition to algorithms, which allow approximate reasoning and inference and the ability to attack problems not rigidly defined. The knowledge base consists of over two-hundred (200) rules and provides links to historical and environmental databases. The environmental causes considered are bulk charging, single event upsets (SEU), surface charging, and total radiation dose. The system's driver translates forward chaining rules into a backward chaining sequence, prompting the user for information pertinent to the causes considered. The use of heuristics frees the user from searching through large amounts of irrelevant information and allows the user to input partial information (varying degrees of confidence in an answer) or 'unknown' to any question. The modularity of the expert system allows for easy updates and modifications. It not only provides scientists with needed risk analysis and confidence not found in algorithmic programs, but is also an effective learning tool, and the window implementation makes it very easy to use. The system currently runs on a Micro VAX II at Goddard Space Flight Center (GSFC). The inference engine used is NASA's C Language Integrated Production System (CLIPS).

  5. Climate-induced tree mortality: Earth system consequences

    USGS Publications Warehouse

    Adams, Henry D.; Macalady, Alison K.; Breshears, David D.; Allen, Craig D.; Stephenson, Nathan L.; Saleska, Scott; Huxman, Travis E.; McDowell, Nathan G.

    2010-01-01

    One of the greatest uncertainties in global environmental change is predicting changes in feedbacks between the biosphere and the Earth system. Terrestrial ecosystems and, in particular, forests exert strong controls on the global carbon cycle and influence regional hydrology and climatology directly through water and surface energy budgets [Bonan, 2008; Chapin et al., 2008].According to new research, tree mortality associated with elevated temperatures and drought has the potential to rapidly alter forest ecosystems, potentially affecting feedbacks to the Earth system [Allen et al., 2010]. Several lines of recent research demonstrate how tree mortality rates in forests may be sensitive to climate change—particularly warming and drying. This emerging consequence of global change has important effects on Earth system processes (Figure 1).

  6. CD-REST: a system for extracting chemical-induced disease relation in literature.

    PubMed

    Xu, Jun; Wu, Yonghui; Zhang, Yaoyun; Wang, Jingqi; Lee, Hee-Jin; Xu, Hua

    2016-01-01

    Mining chemical-induced disease relations embedded in the vast biomedical literature could facilitate a wide range of computational biomedical applications, such as pharmacovigilance. The BioCreative V organized a Chemical Disease Relation (CDR) Track regarding chemical-induced disease relation extraction from biomedical literature in 2015. We participated in all subtasks of this challenge. In this article, we present our participation system Chemical Disease Relation Extraction SysTem (CD-REST), an end-to-end system for extracting chemical-induced disease relations in biomedical literature. CD-REST consists of two main components: (1) a chemical and disease named entity recognition and normalization module, which employs the Conditional Random Fields algorithm for entity recognition and a Vector Space Model-based approach for normalization; and (2) a relation extraction module that classifies both sentence-level and document-level candidate drug-disease pairs by support vector machines. Our system achieved the best performance on the chemical-induced disease relation extraction subtask in the BioCreative V CDR Track, demonstrating the effectiveness of our proposed machine learning-based approaches for automatic extraction of chemical-induced disease relations in biomedical literature. The CD-REST system provides web services using HTTP POST request. The web services can be accessed fromhttp://clinicalnlptool.com/cdr The online CD-REST demonstration system is available athttp://clinicalnlptool.com/cdr/cdr.html. Database URL:http://clinicalnlptool.com/cdr;http://clinicalnlptool.com/cdr/cdr.html.

  7. Shear-induced solidification of athermal systems with weak attraction

    NASA Astrophysics Data System (ADS)

    Zheng, Wen; Liu, Hao; Xu, Ning

    2016-12-01

    We find that unjammed packings of frictionless particles with rather weak attraction can always be driven into solidlike states by shear. The structure of shear-driven solids evolves continuously with packing fraction from gel-like to jamminglike, but is almost independent of the shear stress. In contrast, both the density of vibrational states (DOVS) and force network evolve progressively with the shear stress. There exists a packing fraction independent shear stress σc, at which the shear-driven solids are isostatic and have a flattened DOVS. Solidlike states induced by a shear stress greater than σc possess properties of marginally jammed solids and are thus strictly defined shear jammed states. Below σc, shear-driven solids with rather different structures are all under isostaticity and share common features in the DOVS and force network. Our study leads to a jamming phase diagram for weakly attractive particles, which reveals the significance of the shear stress in determining properties of shear-driven solids and the connections and distinctions between jamminglike and gel-like states.

  8. Perspectives of induced pluripotent stem cells for cardiovascular system regeneration

    PubMed Central

    Csöbönyeiová, Mária; Polák, Štefan

    2015-01-01

    Induced pluripotent stem cells (iPSCs) hold great promise for basic research and regenerative medicine. They offer the same advantages as embryonic stem cells (ESCs) and moreover new perspectives for personalized medicine. iPSCs can be generated from adult somatic tissues by over-expression of a few defined transcription factors, including Oct4, Sox2, Klf4, and c-myc. For regenerative medicine in particular, the technology provides great hope for patients with incurable diseases or potentially fatal disorders such as heart failure. The endogenous regenerative potentials of adult hearts are extremely limited and insufficient to compensate for myocardial loss occurring after myocardial infarction. Recent discoveries have demonstrated that iPSCs have the potential to significantly advance future cardiovascular regenerative therapies. Moreover, iPSCs can be generated from somatic cells of patients with genetic basis for their disease. This human iPSC derivates offer tremendous potential for new disease models. This paper reviews current applications of iPSCs in cardiovascular regenerative medicine and discusses progress in modeling cardiovascular diseases using iPSCs-derived cardiac cells. PMID:25595188

  9. Wounding induces local resistance but systemic susceptibility to Botrytis cinerea in pepper plants.

    PubMed

    García, Tania; Gutiérrez, Jorge; Veloso, Javier; Gago-Fuentes, Raquel; Díaz, José

    2015-03-15

    Cotyledon wounding in pepper caused the early generation of hydrogen peroxide both locally (cotyledons) and systemically (upper true leaves). However, 72 h later there is a different wound response between local and systemic organs, as shown by resistance to the pathogenic fungus Botrytis cinerea, that increased locally and decreased systemically. Signaling by ethylene and jasmonic acid was assessed by using two inhibitors: 1-methylcyclopropene (MCP, inhibitor of ethylene receptors) and ibuprofen (inhibitor of jasmonate biosynthesis). MCP did not affect the modulation of resistance levels to Botrytis by wounding, ruling out the involvement of ethylene signaling. Ibuprofen did not inhibit wound-induced resistance at the local level, but inhibited wound-induced systemic susceptibility. Moreover, changes of biochemical and structural defenses in response to wounding were studied. Peroxidase activity and the expression of a peroxidase gene (CAPO1) increased locally as a response to wounding, but no changes were observed systemically. Lignin deposition was induced in wounded cotyledons, but was repressed in systemic leaves of wounded plants, whereas soluble phenolics did not change locally and decreased systemically. The expression of two other genes involved in plant defense (CABPR1 and CASC1) was also differentially regulated locally and systemically, pointing to a generalized increase in plant defenses at the local level and a systemic decrease as a response to wounding. Wound-induced defenses at the local level coincided with resistance to the necrotroph fungus B. cinerea, whereas depleted defenses in systemic leaves of wounded plants correlated to induced susceptibility against this pathogen. It may be that the local response acts as a sink of energy resources to mount a defense against pathogens, whereas in systemic organs the resources for defense are lower.

  10. Construction of a stress-induced system in Escherichia coli for efficient polyhydroxyalkanoates production.

    PubMed

    Kang, Zhen; Wang, Qian; Zhang, Haojun; Qi, Qingsheng

    2008-05-01

    In the application of engineered Escherichia coli in industrial polyhydroxybutyrate production process, one of the major concerns is the induction of the metabolic pathway. In this study, we developed a stress-induced system by which the PHB biosynthesis pathways can be induced under stress conditions. Fermentation results showed that recombinant E. coli DH5alpha (pQKZ103) harboring this system was able to accumulate polyhydroxybutyrate up to 85.8% of cell dry weight in minimal glucose medium without adding any inducer. Growth experiment with GFP as a reporter indicated that the induction of this system happened at the late exponential phase and was sensitive to stressed environment. This system can also be applied in many other biotechnological processes.

  11. Oxidative damage of the male reproductive system induced by paraquat.

    PubMed

    Chen, Qing; Zhang, Xin; Zhao, Jin-Yan; Lu, Xiao-Ning; Zheng, Peng-Sheng; Xue, Xiang

    2016-10-20

    The effects of paraquat (PQ) on the male reproductive system are unclear. In this study, male rats were divided into four groups (0, 0.5, 2, and 8 mg/kg) and treated with PQ by oral gavage for 8 weeks. At the end of the experiment, a significant decline in sperm count, motility, and viability and an increase in teratospermia were observed in the PQ-treated group (P < 0.05). Further investigation found that PQ resulted in enhanced lipid peroxidation and more apoptosis in the testis tissues, and apoptosis was likely to be associated with activation of the mitochondrial pathway. In summary, our study demonstrated oxidative damage due to PQ on the male reproductive system.

  12. Robotic reactions: delay-induced patterns in autonomous vehicle systems.

    PubMed

    Orosz, Gábor; Moehlis, Jeff; Bullo, Francesco

    2010-02-01

    Fundamental design principles are presented for vehicle systems governed by autonomous cruise control devices. By analyzing the corresponding delay differential equations, it is shown that for any car-following model short-wavelength oscillations can appear due to robotic reaction times, and that there are tradeoffs between the time delay and the control gains. The analytical findings are demonstrated on an optimal velocity model using numerical continuation and numerical simulation.

  13. Relapsed hydroxychloroquine induced thrombocytopenia in systemic lupus erythematosus patient.

    PubMed

    Antón Vázquez, Vanesa; Pascual, Luis; Corominas, Héctor; Giménez Torrecilla, Isabel

    2016-06-02

    Hydroxychloroquine is used in the long-term therapy of systemic lupus erythematosus (SLE). Although considered to be a safe treatment, side effects have been documented. An uncommon side effect is thrombocytopenia. In order to establish the diagnosis of thrombocytopenia secondary to Hydroxychloroquine, non-pharmacological causes must be ruled out and it is necessary to determine a recurrence after re-exposure to the drug. We present one case of severe thrombocytopenia occurring in a patient with SLE undergoing treatment with Hydroxychloroquine.

  14. Flow-Induced Control of Pattern Formation in Chemical Systems

    NASA Astrophysics Data System (ADS)

    Berenstein, Igal; Beta, Carsten

    Since Alan Turing's seminal paper in 1952, the study of spatio-temporal patterns that arise in systems of reacting and diffusing components has grown into an immense and vibrant realm of scientific research. This field includes not only chemical systems but spans many areas of science as diverse as cell and developmental biology, ecology, geosciences, or semiconductor physics. For several decades research in this field has concentrated on the vast variety of patterns that can emerge in reaction-diffusion systems and on the underlying instabilities. In the 1990s, stimulated by the pioneering work of Ott, Grebogi and Yorke, control of pattern formation arose as a new topical focus and gradually developed into an entire new field of research. On the one hand, research interests concentrated on control and suppression of undesired dynamical states, in particular on control of chaos. On the other hand, the design and engineering of particular space-time patterns became a major focus in this field that motivates ongoing scientific effort until today...

  15. Virgin coconut oil supplementation ameliorates cyclophosphamide-induced systemic toxicity in mice.

    PubMed

    Nair, S S; Manalil, J J; Ramavarma, S K; Suseela, I M; Thekkepatt, A; Raghavamenon, A C

    2016-02-01

    Virgin coconut oil (VCO) is an unrefined kernal oil, prepared from Cocos nucifera L., having substantial nutritional and medicinal value. Experimental studies have suggested its antioxidant, anti-inflammatory, immunostimulatory and hypolipidemic effects. The present study assesses its effect on formalin-induced chronic inflammation and cyclophosphamide (CTX)-induced systemic toxicity in murine models. Oral administration of VCO effectively reduced formalin-induced paw oedema in mice with more or less similar efficacy as that of diclofenac. The CTX-induced hike in blood urea, creatinine, thiobarbituric acid reactive substances (TBARS) and liver marker enzymes in mice was marginally decreased by VCO (8 g/kg body weight) ingestion orally. The liver and kidney catalase, superoxide dismutase and glutathione peroxidase activities, together with cellular glutathione and TBARS levels, were found to be improved in these animals. Overall the study reveals the protective efficacy of VCO against secondary toxicity induced by CTX possibly through its antioxidant and anti-inflammatory properties.

  16. Flow-induced vibration and instability of some nuclear-reactor-system components. [PWR

    SciTech Connect

    Chen, S.S.

    1983-01-01

    The high-velocity coolant flowing through a reactor system component is a source of energy that can induce component vibration and instability. In fact, many reactor components have suffered from excessive vibration and/or dynamic instability. The potential for detrimental flow-induced vibration makes it necessary that design engineers give detailed considerations to the flow-induced vibration problems. Flow-induced-vibration studies have been performed in many countries. Significant progress has been made in understanding the different phenomena and development of design guidelines to avoid damaging vibration. The purpose of this paper is to present an overview of the recent progress in several selected areas, to discuss some new results and to indentify future research needs. Specifically, the following areas will be presented: examples of flow-induced-vibration problems in reactor components; excitation mechanisms and component response characteristics; instability mechanisms and stability criteria; design considerations; and future research needs.

  17. Local and systemic biochemical alterations induced by Bothrops atrox snake venom in mice

    PubMed Central

    de Souza, Carlos AT; Kayano, Anderson M; Setúbal, Sulamita S; Pontes, Adriana S; Furtado, Juliana L; Kwasniewski, Fábio H; Zaqueo, Kayena D; Soares, Andreimar M; Stábeli, Rodrigo G; Zuliani, Juliana P

    2012-01-01

    The local and systemic alterations induced by Bothrops atrox snake venom (BaV) injection in mice were studied. BaV induced superoxide production by migrated neutrophils, mast cell degranulation and phagocytosis by macrophages. Moreover, BaV caused hemorrhage in dorsum of mice after 2hr post- injection. Three hours post-injection in gastrocnemius muscle, we also observed myonecrosis, which was assessed by the determination of serum and tissue CK besides the release of urea, but not creatinine and uric acid, indicating kidney alterations. BaV also induced the release of LDH and transaminases (ALT and AST) indicating tissue and liver abnormalities. In conclusion, the data indicate that BaV induces events of local and systemic importance. PMID:23487552

  18. Bistability of the naturally induced lactose utilization system of Escherichia coli

    NASA Astrophysics Data System (ADS)

    Stajic, Jelena; Wall, Michael

    2006-03-01

    In the absence of the preferred sugar glucose, lactose utilization machinery in the bacterium E. coli is activated. The genetic circuit responsible for this response, lac operon, has been observed to exhibit bistability when induced by an artificial inducer, TMG. Here we investigate conditions under which bistability might be observed in response to lactose. The aim of our study is to establish whether the natural system exhibits bistability, as is often assumed despite the lack of experimental support.

  19. Gut Microbiota-Induced Immunoglobulin G Controls Systemic Infection by Symbiotic Bacteria and Pathogens

    PubMed Central

    Zeng, Melody Y.; Cisalpino, Daniel; Varadarajan, Saranyaraajan; Hellman, Judith; Warren, H. Shaw; Cascalho, Marilia; Inohara, Naohiro; Núñez, Gabriel

    2016-01-01

    The gut microbiota is compartmentalized in the intestinal lumen and induces local immune responses, but it remains unknown whether the gut microbiota can induce systemic response and contribute to systemic immunity. We report that selective gut symbiotic gram-negative bacteria were able to disseminate systemically to induce immunoglobulin G (IgG) response, which primarily targeted gram-negative bacterial antigens and conferred protection against systemic infections by E. coli and Salmonella by directly coating bacteria to promote killing by phagocytes. T cells and Toll-like receptor 4 on B cells were important in the generation of microbiota-specific IgG. We identified murein lipoprotein (MLP), a highly conserved gram-negative outer membrane protein, as a major antigen that induced systemic IgG homeostatically in both mice and humans. Administration of anti-MLP IgG conferred crucial protection against systemic Salmonella infection. Thus, our findings reveal an important function for the gut microbiota in combating systemic infection through the induction of protective IgG. PMID:26944199

  20. Gadolinium contrast agent-induced CD163+ ferroportin+ osteogenic cells in nephrogenic systemic fibrosis.

    PubMed

    Swaminathan, Sundararaman; Bose, Chhanda; Shah, Sudhir V; Hall, Kimberly A; Hiatt, Kim M

    2013-09-01

    Gadolinium-based contrast agents are linked to nephrogenic systemic fibrosis in patients with renal insufficiency. The pathology of nephrogenic systemic fibrosis is characterized by abnormal tissue repair: fibrosis and ectopic ossification. The mechanisms by which gadolinium could induce fibrosis and ossification are not known. We examined in vitro the effect of a gadolinium-based contrast agent on human peripheral blood mononuclear cells for phenotype and function relevant to the pathology of nephrogenic systemic fibrosis using immunofluorescence, flow cytometry, real-time PCR, and osteogenic assays. We also examined tissues from patients with nephrogenic systemic fibrosis, using IHC to identify the presence of cells with phenotype induced by gadolinium. Gadolinium contrast induced differentiation of human peripheral blood mononuclear cells into a unique cellular phenotype--CD163(+) cells expressing proteins involved in fibrosis and bone formation. These cells express fibroblast growth factor (FGF)23, osteoblast transcription factors Runt-related transcription factor 2, and osterix, and show an osteogenic phenotype in in vitro assays. We show in vivo the presence of CD163(+)/procollagen-1(+)/osteocalcin(+) cells in the fibrotic and calcified tissues of nephrogenic systemic fibrosis patients. Gadolinium contrast-induced CD163(+)/ferroportin(+)/FGF23(+) cells with osteogenic potential may play a role in systemic fibrosis and ectopic ossification in nephrogenic systemic fibrosis.

  1. Insult-induced adaptive plasticity of the auditory system

    PubMed Central

    Gold, Joshua R.; Bajo, Victoria M.

    2014-01-01

    The brain displays a remarkable capacity for both widespread and region-specific modifications in response to environmental challenges, with adaptive processes bringing about the reweighing of connections in neural networks putatively required for optimizing performance and behavior. As an avenue for investigation, studies centered around changes in the mammalian auditory system, extending from the brainstem to the cortex, have revealed a plethora of mechanisms that operate in the context of sensory disruption after insult, be it lesion-, noise trauma, drug-, or age-related. Of particular interest in recent work are those aspects of auditory processing which, after sensory disruption, change at multiple—if not all—levels of the auditory hierarchy. These include changes in excitatory, inhibitory and neuromodulatory networks, consistent with theories of homeostatic plasticity; functional alterations in gene expression and in protein levels; as well as broader network processing effects with cognitive and behavioral implications. Nevertheless, there abounds substantial debate regarding which of these processes may only be sequelae of the original insult, and which may, in fact, be maladaptively compelling further degradation of the organism's competence to cope with its disrupted sensory context. In this review, we aim to examine how the mammalian auditory system responds in the wake of particular insults, and to disambiguate how the changes that develop might underlie a correlated class of phantom disorders, including tinnitus and hyperacusis, which putatively are brought about through maladaptive neuroplastic disruptions to auditory networks governing the spatial and temporal processing of acoustic sensory information. PMID:24904256

  2. Novel and tightly regulated resorcinol and cumate-inducible expression systems for Streptomyces and other actinobacteria.

    PubMed

    Horbal, Liliya; Fedorenko, Victor; Luzhetskyy, Andriy

    2014-10-01

    Inducible expression is a versatile genetic tool for controlling gene transcription, determining gene functions and other uses. Herein, we describe our attempts to create several inducible systems based on a cumate or a resorcinol switch, a hammerhead ribozyme, the LacI repressor, and isopropyl β-d-thiogalactopyranoside (IPTG). We successfully developed a new cumate (p-isopropylbenzoic acid)-inducible gene switch in actinobacteria that is based on the CymR regulator, the operator sequence (cmt) from the Pseudomonas putida cumate degradation operon and P21 synthetic promoter. Resorcinol-inducible expression system is also functional and is composed of the RolR regulator and the PA3 promoter fused with the operator (rolO) from the Corynebacterium glutamicum resorcinol catabolic operon. Using the gusA (β-glucuronidase) gene as a reporter, we showed that the newly generated expression systems are tightly regulated and hyper-inducible. The activity of the uninduced promoters is negligible in both cases. Whereas the induction factor reaches 45 for Streptomyces albus in the case of cumate switch and 33 in the case of resorcinol toggle. The systems are also dose-dependent, which allows the modulation of gene expression even from a single promoter. In addition, the cumate system is versatile, given that it is functional in different actinomycetes. Finally, these systems are nontoxic and inexpensive, as these are characteristics of cumate and resorcinol, and they are easy to use because inducers are water-soluble and easily penetrate cells. Therefore, the P21-cmt-CymR and PA3-rolO-RolR systems are powerful tools for engineering actinobacteria.

  3. Mechanistic insight into the norepinephrine-induced fibrosis in systemic sclerosis

    PubMed Central

    Uehara, Akihito; Motegi, Sei-ichiro; Yamada, Kazuya; Uchiyama, Akihiko; Perera, Buddhini; Toki, Sayaka; Ogino, Sachiko; Yokoyama, Yoko; Takeuchi, Yuko; Ishikawa, Osamu

    2016-01-01

    Raynaud’s phenomenon is frequently observed in systemic sclerosis (SSc) patients, and cold- or stress-induced norepinephrine (NE) has been speculated to be associated with vasoconstriction. Objective was to elucidate the role of NE in fibrosis in SSc. IL-6 is a potent stimulator of collagen production in fibroblasts. NE enhanced IL-6 production and proliferation more significantly in SSc fibroblasts than in normal fibroblasts. Furthermore, the production of IL-6 and phosphorylation of p38 in SSc fibroblasts was enhanced by adrenergic receptor (AR)β agonist, isoproterenol, but not ARα agonist, oxymetazoline. ARβ blocker, propranolol, inhibited NE-induced IL-6 production and phosphorylation of p38 in SSc fibroblasts. NE-induced IL-6 was significantly inhibited by p38 inhibitor, SB203580, suggesting that NE-induced phosphorylation of p38 via ARβ enhances IL-6 production in SSc fibroblasts. NE-induced phosphorylation of ERK1/2 via ARα inhibited IL-6 production in SSc fibroblasts. Combined treatment with NE and endothelin-1 resulted in an additive increase in IL-6 production in SSc fibroblasts. NE-induced IL-6/IL-6 receptor trans-signaling increased the production of collagen type I in SSc fibroblasts, and both propranolol and SB203580 inhibited NE-induced collagen production. These results suggest that cold exposure and/or emotional stress-induced NE might contribute to the skin fibrosis via potentiation of IL-6 production from fibroblasts in SSc. PMID:27650973

  4. Growth-induced non-stoichiometry in complex oxide systems

    NASA Astrophysics Data System (ADS)

    Breckenfeld, Eric

    Complex perovskite oxides have been studied extensively over the past few decades due to their wide range of functional properties and relative ease of epitaxial synthesis. These two factors have allowed such oxide systems to see a multitude of applications including sensors, memory, thermal management, and energy harvesting. The ability to access so many different functionalities is owed largely to the chemical diversity available to the perovskite unit cell, opening the door for metal-insulator-transitions, ferroelectricity, and superconductivity, to name a few. However, the same chemical diversity that enables so many potential applications also opens the door for a myriad of chemistry-related defects. Separating out the relative contributions of such extrinsic (or defect-driven) effects from the intrinsic material properties is crucial to enabling the use of these materials in high-performance, next-generation devices. In this work, we examine several model systems in order to explore the relationship between the pulsed laser deposition growth process, the film chemistry, and the subsequent effects on the defect landscape and film properties. We show that small changes to the laser fluence can have a marked impact on the chemical composition of the film, leading to cation stoichiometry deviations as large as 10% in SrTiO3, LaAlO3, and NdNiO3 systems. We demonstrate that such chemical deviations can lead to significant changes in the bulk thermal and dielectric properties of SrTiO3 and LaAlO3 films. We have also investigated the interface between SrTiO3 and LaAlO3, which has been studied extensively over the past 8 years due to the supposed presence of a 2-dimensional electron gas (2DEG). Our results indicate that the presence of cation defects in the LaAlO3 has a profound impact on the electronic properties of the 2DEG interface. Finally, we have similarly shown that cation non-stoichiometry can cause the metal-insulator-transition material NdNiO3 to behave

  5. Tyre induced vibrations of the car-trailer system

    NASA Astrophysics Data System (ADS)

    Beregi, S.; Takács, D.; Stépán, G.

    2016-02-01

    The lateral and yaw dynamics of the car-trailer combination are analysed by means of a single track model. The equations of motion are derived rigorously by means of the Appell-Gibbs equations for constant longitudinal velocity of the vehicle. The tyres are described with the help of the so-called delayed tyre model, which is based on a brush model with pure rolling contact. The lateral forces and aligning torques of the tyre/road interaction are calculated via the instantaneous lateral deformations in the contact patches. The linear stability analysis of the rectilinear motion is performed via the analytically determined characteristic function of the system. Stability charts are constructed with respect to the vehicle longitudinal velocity and the payload position on the trailer. Self-excited lateral vibrations are detected with different vibration modes at low and at high longitudinal speeds of the vehicle. The effects of the tyre parameters are also investigated.

  6. Central nervous system dysfunction in obesity-induced hypertension.

    PubMed

    Head, Geoffrey A; Lim, Kyungjoon; Barzel, Benjamin; Burke, Sandra L; Davern, Pamela J

    2014-09-01

    The activation of the sympathetic nervous system is a major mechanism underlying both human and experimental models of obesity-related hypertension. While insulin and the adipokine leptin have long been thought to contribute to obesity-related neurogenic mechanisms, the evidence is now very strong that they play a major role, shown particularly in animal studies using selective receptor antagonists. There is not just maintenance of leptin's sympatho-excitatory actions as previously suggested but considerable amplification particularly in renal sympathetic nervous activity. Importantly, these changes are not dependent on short-term elevation or reduction in plasma leptin or insulin, but require some weeks to develop indicating a slow "neural adaptivity" within hypothalamic signalling. These effects can be carried across generations even when offspring are raised on a normal diet. A better understanding of the underlying mechanism should be a high research priority given the prevalence of obesity not just in the current population but also for future generations.

  7. Triggered Swarms and Induced Aftershock Sequences in Geothermal Systems

    NASA Astrophysics Data System (ADS)

    Shcherbakov, R.; Turcotte, D. L.; Yikilmaz, M. B.; Kellogg, L. H.; Rundle, J. B.

    2015-12-01

    Natural geothermal systems, which are used for energy generation, are usually associated with high seismic activity. This can be related to the large-scale injection and extraction of fluids to enhance geothermal recovery. This results in the changes of the pore pressure and pore-elastic stress field and can stimulate the occurrence of earthquakes. These systems are also prone to triggering of seismicity by the passage of seismic waves generated by large distant main shocks. In this study, we analyze clustering and triggering of seismicity at several geothermal fields in California. Particularly, we consider the seismicity at the Geysers, Coso, and Salton Sea geothermal fields. We analyze aftershock sequences generated by local large events with magnitudes greater than 4.0 and earthquake swarms generated by several significant long distant main shocks. We show that the rate of the aftershock sequences generated by the local large events in the two days before and two days after the reference event can be modelled reasonably well by the time dependent Epidemic Type Aftershock Sequence (ETAS) model. On the other hand, the swarms of activity triggered by large distant earthquakes cannot be described by the ETAS model. To model the increase in the rate of seismicity associated with triggering by large distant main shocks we introduce an additional time-dependent triggering mechanism into the ETAS model. In almost all cases the frequency-magnitude statistics of triggered sequences follow Gutenberg-Richter scaling to a good approximation. The analysis indicates that the seismicity triggered by relatively large local events can initiate sequences similar to regular aftershock sequences. In contrast, the distant main shocks trigger swarm like activity with faster decaying rates.

  8. Screening system for drug-induced arrhythmogenic risk combining a patch clamp and heart simulator

    PubMed Central

    Okada, Jun-ichi; Yoshinaga, Takashi; Kurokawa, Junko; Washio, Takumi; Furukawa, Tetsushi; Sawada, Kohei; Sugiura, Seiryo; Hisada, Toshiaki

    2015-01-01

    To save time and cost for drug discovery, a paradigm shift in cardiotoxicity testing is required. We introduce a novel screening system for drug-induced arrhythmogenic risk that combines in vitro pharmacological assays and a multiscale heart simulator. For 12 drugs reported to have varying cardiotoxicity risks, dose-inhibition curves were determined for six ion channels using automated patch clamp systems. By manipulating the channel models implemented in a heart simulator consisting of more than 20 million myocyte models, we simulated a standard electrocardiogram (ECG) under various doses of drugs. When the drug concentrations were increased from therapeutic levels, each drug induced a concentration-dependent characteristic type of ventricular arrhythmia, whereas no arrhythmias were observed at any dose with drugs known to be safe. We have shown that our system combining in vitro and in silico technologies can predict drug-induced arrhythmogenic risk reliably and efficiently. PMID:26601174

  9. Dual coupled-resonator system for plasmon-induced transparency and slow light effect

    NASA Astrophysics Data System (ADS)

    Wang, Qinghao; Meng, Hongyun; Huang, Ben; Wang, Huihao; Zhang, Xing; Yu, Wei; Tan, Chunhua; Huang, Xuguang; Li, Shuti

    2016-12-01

    We proposed a dual coupled-resonator system based on the metal-insulator-metal bus waveguide and numerically investigated the plasmon-induced transparency and slow light effect with the Finite-Difference Time-Domain simulations in this paper. The electromagnetically induced transparency-like spectral response will occur between two adjacent stub resonators with detuned resonant wavelength due to the phase-coupled effect. The transmissivity and group index equations were been deduced, which indicated that the system can achieve the effect of the multiple electromagnetically induced transparency-like and slow light. With the optimization, the single peak transmission can reach to as high as 92%, dual PIT transmission peaks appear, as well as group index can reach over 75. These characteristics indicate multiple applications of our system in integrated optical circuits.

  10. A self-inducible heterologous protein expression system in Escherichia coli

    PubMed Central

    Briand, L.; Marcion, G.; Kriznik, A.; Heydel, J. M.; Artur, Y.; Garrido, C.; Seigneuric, R.; Neiers, F.

    2016-01-01

    Escherichia coli is an important experimental, medical and industrial cell factory for recombinant protein production. The inducible lac promoter is one of the most commonly used promoters for heterologous protein expression in E. coli. Isopropyl-β-D-thiogalactoside (IPTG) is currently the most efficient molecular inducer for regulating this promoter’s transcriptional activity. However, limitations have been observed in large-scale and microplate production, including toxicity, cost and culture monitoring. Here, we report the novel SILEX (Self-InducibLe Expression) system, which is a convenient, cost-effective alternative that does not require cell density monitoring or IPTG induction. We demonstrate the broad utility of the presented self-inducible method for a panel of diverse proteins produced in large amounts. The SILEX system is compatible with all classical culture media and growth temperatures and allows protein expression modulation. Importantly, the SILEX system is proven to be efficient for protein expression screening on a microplate scale. PMID:27611846

  11. Colored Noise Induced Bistable Switch in the Genetic Toggle Switch Systems.

    PubMed

    Wang, Pei; Lü, Jinhu; Yu, Xinghuo

    2015-01-01

    Noise can induce various dynamical behaviors in nonlinear systems. White noise perturbed systems have been extensively investigated during the last decades. In gene networks, experimentally observed extrinsic noise is colored. As an attempt, we investigate the genetic toggle switch systems perturbed by colored extrinsic noise and with kinetic parameters. Compared with white noise perturbed systems, we show there also exists optimal colored noise strength to induce the best stochastic switch behaviors in the single toggle switch, and the best synchronized switching in the networked systems, which demonstrate that noise-induced optimal switch behaviors are widely in existence. Moreover, under a wide range of system parameter regions, we find there exist wider ranges of white and colored noises strengths to induce good switch and synchronization behaviors, respectively; therefore, white noise is beneficial for switch and colored noise is beneficial for population synchronization. Our observations are very robust to extrinsic stimulus strength, cell density, and diffusion rate. Finally, based on the Waddington's epigenetic landscape and the Wiener-Khintchine theorem, physical mechanisms underlying the observations are interpreted. Our investigations can provide guidelines for experimental design, and have potential clinical implications in gene therapy and synthetic biology.

  12. PeaT1-induced systemic acquired resistance in tobacco follows salicylic acid-dependent pathway.

    PubMed

    Zhang, Wei; Yang, Xiufen; Qiu, Dewen; Guo, Lihua; Zeng, Hongmei; Mao, Jianjun; Gao, Qiufeng

    2011-04-01

    Systemic acquired resistance (SAR) is an inducible defense mechanism which plays a central role in protecting plants from pathogen attack. A new elicitor, PeaT1 from Alternaria tenuissima, was expressed in Escherichia coil and characterized with systemic acquired resistance to tobacco mosaic virus (TMV). PeaT1-treated plants exhibited enhanced systemic resistance with a significant reduction in number and size of TMV lesions on wild tobacco leaves as compared with control. The quantitative analysis of TMV CP gene expression with real-time quantitative PCR showed there was reduction in TMV virus concentration after PeaT1 treatment. Similarly, peroxidase (POD) activity and lignin increased significantly after PeaT1 treatment. The real-time quantitative PCR revealed that PeaT1 also induced the systemic accumulation of pathogenesis-related gene, PR-1a and PR-1b which are the markers of systemic acquired resistance (SAR), NPR1 gene for salicylic acid (SA) signal transduction pathway and PAL gene for SA synthesis. The accumulation of SA and the failure in development of similar level of resistance as in wild type tobacco plants in PeaT1 treated nahG transgenic tobacco plants indicated that PeaT1-induced resistance depended on SA accumulation. The present work suggested that the molecular mechanism of PeaT1 inducing disease resistance in tobacco was likely through the systemic acquired resistance pathway mediated by salicylic acid and the NPR1 gene.

  13. Geometrically Induced Nonlinearity in Materials and Structural Systems

    NASA Astrophysics Data System (ADS)

    Ebrahimi, Hamid

    For structural analysis there are three sources of nonlinear behavior. The corresponding nonlinear effects are identified by material, geometry and boundary condition nonlinearities. Here in the present work we focused on nonlinear behavior of structural systems that arises from geometry and specifically tackled three problems: nonlinearity in shell structures, nonlinearity in scale-substrate systems and nonlinearity is cellular solids. Firstly, we present a new instability that is observed in the indentation of a highly ellipsoidal shell by a horizontal plate. Above a critical indentation depth, the plate loses contact with the shell in a series of well-defined `blisters' along the long axis of the ellipsoid. We characterize the onset of this instability and explain it using scaling arguments, numerical simulations and experiments. We also characterize the properties of the blistering pattern by showing how the number of blisters and their size depend on both the geometrical properties of the shell and the indentation but not on the shell's elastic modulus. This blistering instability may be used to determine the thickness of highly ellipsoidal shells simply by squashing them between two plates. For the second problem, we investigate the nonlinear mechanical effects of biomimetic scale like attachments on the behavior of an elastic substrate brought about by the contact interaction of scales in pure bending using qualitative experiments, analytical models and detailed finite element analysis. Our results reveal the existence of three distinct kinematic phases of operation spanning linear, nonlinear and rigid behavior driven by kinematic interactions of scales. The response of the modified elastic beam strongly depends on the size and spatial overlap of rigid scales. The nonlinearity is perceptible even in relatively small strain regime and without invoking material level complexities of either the scales or the substrate. And lastly, we develop a new class of two

  14. Heavy oil fractions induce negative influences on mouse immune system.

    PubMed

    Nishimoto, Sogo; Kanda, Kota; Yamawaki, Manami; Okabe, Masaaki; Akiyama, Koichi; Kakinuma, Yoshimi; Sugahara, Takuya

    2009-10-01

    It is well known that heavy oil such as pollutant caused serious influences on the marine ecosystem. We may suffer from various disorders in our body via intake of marine foods polluted with heavy oil. However the influences of heavy oil on our immune system have not yet been clarified. Here we show the effects of heavy oil extracts, water-soluble fraction (WSF), methanol-soluble fraction (MSF) and ethanol-soluble fraction (ESF), on immunoglobulin production of mouse splenocytes. All extracts increased IgA productivity of splenocytes. In oral administration, shrinkage of the immune organs such as spleen or thymus was observed in only WSF-administrated mice at least during 7 days. The amount of IgG production level in splenocytes cultured medium and sera were reduced by each extract administration. A flowcytometry method, to monitor splenocytes of WSF-administrated mice, has been set up using double staining with B and T cell-specific surface antibody. The results from cell population analysis indicated that B cells, including plasma cells producing antibody were reduced. The decrease in IgG level in sera was caused by reduction of plasma cells in spleen. Hence, it is suggested that reduction of Ig production was affected by the chemical compounds contained in WSF possibly such as polycyclic aromatic hydrocarbons (PAHs) through the estrogen receptor expressed in lymphocytes.

  15. Docetaxel-Induced Systemic Sclerosis with Internal Organ Involvement Masquerading as Congestive Heart Failure

    PubMed Central

    Vemulapalli, Raghavendra C.; Gupta, Amit; Shreve, Maria E.; Rees, Della A.

    2017-01-01

    Systemic sclerosis, or scleroderma, is a complex medical disorder characterized by limited or diffuse skin thickening with frequent involvement of internal organs such as lungs, gastrointestinal tract, or kidneys. Docetaxel is a chemotherapeutic agent which has been associated with cutaneous side effects. An uncommon cutaneous side effect of docetaxel is scleroderma-like skin changes that extend from limited to diffuse cutaneous systemic sclerosis. Several case reports have been published regarding the association of docetaxel and systemic sclerosis. However, those reports demonstrated the association between docetaxel and scleroderma-like skin changes without internal organ involvement. Here, we report a case of systemic sclerosis with pulmonary arterial hypertension and a microangiopathic kidney involvement induced by docetaxel chemotherapy. After an exhaustive literature review, this could be the first case of docetaxel-induced systemic sclerosis involving internal organs. PMID:28265474

  16. Docetaxel-Induced Systemic Sclerosis with Internal Organ Involvement Masquerading as Congestive Heart Failure.

    PubMed

    Park, Bumsoo; Vemulapalli, Raghavendra C; Gupta, Amit; Shreve, Maria E; Rees, Della A

    2017-01-01

    Systemic sclerosis, or scleroderma, is a complex medical disorder characterized by limited or diffuse skin thickening with frequent involvement of internal organs such as lungs, gastrointestinal tract, or kidneys. Docetaxel is a chemotherapeutic agent which has been associated with cutaneous side effects. An uncommon cutaneous side effect of docetaxel is scleroderma-like skin changes that extend from limited to diffuse cutaneous systemic sclerosis. Several case reports have been published regarding the association of docetaxel and systemic sclerosis. However, those reports demonstrated the association between docetaxel and scleroderma-like skin changes without internal organ involvement. Here, we report a case of systemic sclerosis with pulmonary arterial hypertension and a microangiopathic kidney involvement induced by docetaxel chemotherapy. After an exhaustive literature review, this could be the first case of docetaxel-induced systemic sclerosis involving internal organs.

  17. Construction of an inducible cell-communication system that amplifies Salmonella gene expression in tumor tissue.

    PubMed

    Dai, Yumei; Toley, Bhushan J; Swofford, Charles A; Forbes, Neil S

    2013-06-01

    Bacterial therapies have the potential to overcome resistances that cause chemotherapies to fail. When using bacteria to produce anticancer agents in tumors, triggering gene expression is necessary to prevent systemic toxicity. The use of chemical triggers, however, is hampered by poor delivery of inducing molecules, which reduces the number of activated bacteria. To solve this problem, we created a cell-communication system that enables activated bacteria to induce inactive neighbors. We hypothesized that introducing cell communication into Salmonella would improve direct triggering strategies by increasing protein production, increasing sensitivity to inducer molecules, and enabling expression in tumor tissue. To test these hypotheses we integrated the PBAD promoter into the quorum-sensing machinery from Vibrio fischeri. The expression of a fluorescent reporter gene was compared to expression from non-communicating controls. Function in three-dimensional tissue was tested in a tumor-on-a-chip device. Bacterial communication increased fluorescence 40-fold and increased sensitivity to inducer molecules more than 10,000-fold. The system enabled bacteria to activate neighbors and increased the time-scale of protein production. Gene expression was controllable and tightly regulated. At the optimal inducing signal, communicating bacteria produced 350 times more protein than non-communicating bacteria. The cell-communication system created in this study has uses beyond cancer therapy, including protein manufacturing, bioremediation and biosensing. It would enable amplified induction of gene expression in any environment that limits availability of inducer molecules. Ultimately, because inducible cellular communication enables gene expression in tissue, it will be a critical component of bacterial anticancer therapies.

  18. Products of an Artificially Induced Hydrothermal System at Yucca Mountain

    SciTech Connect

    S. Levy

    2000-08-07

    Studies of mineral deposition in the recent geologic past at Yucca Mountain, Nevada, address competing hypotheses of hydrothermal alteration and deposition from percolating groundwater. The secondary minerals being studied are calcite-opal deposits in fractures and lithophysal cavities of ash-flow tuffs exposed in the Exploratory Studies Facility (ESF), a 7.7-km tunnel excavated by the Yucca Mountain Site Characterization Project within Yucca Mountain. An underground field test in the ESF provided information about the minerals deposited by a short-lived artificial hydrothermal system and an opportunity for comparison of test products with the natural secondary minerals. The heating phase lasted nine months, followed by a nine-month cooling period. Natural pore fluids were the only source of water during the thermal test. Condensation and reflux of water driven away from the heater produced fluid flow in certain fractures and intersecting boreholes. The mineralogic products of the thermal test are calcite-gypsum aggregates of less than 4-micrometer crystals and amorphous silica as glassy scale less than 0.2 mm thick and as mounds of tubules with diameters less than 0.7 micrometers. The minute crystal sizes of calcite and gypsum from the field test are very different from the predominantly coarser calcite crystals (up to cm scale) in natural secondary-mineral deposits at the site. The complex micrometer-scale textures of the amorphous silica differ from the simple forms of opal spherules and coatings in the natural deposits, even though some natural spherules are as small as 1 micrometer. These differences suggest that the natural minerals, especially if they were of hydrothermal origin, may have developed coarser or simpler forms during subsequent episodes of dissolution and redeposition. The presence of gypsum among the test products and its absence from the natural secondary-mineral assemblage may indicate a higher degree of evaporation during the test than

  19. Storm-induced response of a nearshore-bar system

    USGS Publications Warehouse

    Sallenger, A.H.; Holman, R.A.; Birkemeier, W.A.

    1985-01-01

    A nearshore-bar system was surveyed periodically through a storm and the following recovery period. The data showed a very rapid response of morphology to changing wave conditions and allowed various models on bar formation to be tested. Under low-energy conditions prior to the storm a small bar was surveyed 13 m offshore. Both the high reflectivity of the beach and the cross-shore distance to the bar are consistent with a model of sediment convergence at the node or antinode of a standing wave of incident period. Such a small-scale bar may be a common feature on beaches with steep foreshores and more gentle offshore slopes. With the increase in wave height during the storm, the bar became better developed and migrated offshore at rates up to 2.2 m h-1. The bar maintained its form in that the ratio of trough depth to crest depth ( ht hc) remained roughly constant. The bar was in no way related to processes which would cause the convergence of sediment in the breaker zone; through most of the storm the bar-crest distance offshore was typically only 10% of the surf-zone width. Analysis of the bar distance offshore in terms of a standing wave motion showed that the causative wave period must have been much longer than that of incident waves, probably on the order of a minute. Surf-zone wave data showed significant energy in the infragravity band at these periods although no definite link has been made. After the height of the storm, the bar had a crescentic morphology. The development of this morphology occurred very rapidly with parts of the bar migrating onshore at rates up to 1.2 m h-1. In contrast to the storm, during the recovery period ht hc varied by nearly a factor of three. Analysis of the offshore and longshore length scales showed the bar to be similar to one which would be generated by a standing mode 1 edge wave of period on the order of one minute. ?? 1985.

  20. Ameliorative Effect of Ginsenoside Rg1 on Lipopolysaccharide-Induced Cognitive Impairment: Role of Cholinergic System.

    PubMed

    Jin, Yang; Peng, Jian; Wang, Xiaona; Zhang, Dong; Wang, Tianyin

    2017-01-11

    Bacterial endotoxin lipopolysaccharide (LPS) can induce systemic inflammation, and therefore disrupt learning and memory processes. Ginsenoside Rg1, a major bioactive component of ginseng, is shown to greatly improve cognitive function. The present study was designed to further investigate whether administration of ginsenoside Rg1 can ameliorate LPS-induced cognitive impairment in the Y-maze and Morris water maze (MWM) task, and to explore the underlying mechanisms. Results showed that exposure to LPS (500 μg/kg) significantly impaired working and spatial memory and that repeated treatment with ginsenoside Rg1 (200 mg/kg/day, for 30 days) could effectively alleviate the LPS-induced cognitive decline as indicated by increased working and spatial memory in the Y-maze and MWM tests. Furthermore, ginsenoside Rg1 treatment prevented LPS-induced decrease of acetylcholine (ACh) levels and increase of acetylcholinesterase (AChE) activity. Ginsenoside Rg1 treatment also reverted the decrease of alpha7 nicotinic acetylcholine receptor (α7 nAChR) protein expression in the prefrontal cortex (PFC) and hippocampus of LPS-treated rats. These findings suggest that ginsenoside Rg1 has protective effect against LPS-induced cognitive deficit and that prevention of LPS-induced changes in cholinergic system is crucial to this ameliorating effect.

  1. System for stable β-estradiol-inducible gene expression in the moss Physcomitrella patens.

    PubMed

    Kubo, Minoru; Imai, Akihiro; Nishiyama, Tomoaki; Ishikawa, Masaki; Sato, Yoshikatsu; Kurata, Tetsuya; Hiwatashi, Yuji; Reski, Ralf; Hasebe, Mitsuyasu

    2013-01-01

    Inducible transgene expression provides a useful tool to analyze gene function. The moss Physcomitrellapatens is a model basal land plant with well-developed research tools, including a high efficiency of gene targeting and substantial genomics resources. However, current systems for controlled transgene expression remain limited. Here we report the development of an estrogen receptor mediated inducible gene expression system, based on the system used in flowering plants. After identifying the appropriate promoters to drive the chimeric transducer, we succeeded in inducing transcription over 1,000-fold after 24 h incubation with β-estradiol. The P. patens system was also effective for high-level long-term induction of gene expression; transcript levels of the activated gene were maintained for at least seven days on medium containing β-estradiol. We also established two potentially neutral targeting sites and a set of vectors for reproducible expression of two transgenes. This β-estradiol-dependent system will be useful to test genes individually or in combination, allowing stable, inducible transgenic expression in P. patens.

  2. High molecular weight RNAs and small interfering RNAs induce systemic posttranscriptional gene silencing in plants

    PubMed Central

    Klahre, Ulrich; Crété, Patrice; Leuenberger, Sabrina A.; Iglesias, Victor A.; Meins, Frederick

    2002-01-01

    Posttranscriptional gene silencing (PTGS) in transgenic plants is an epigenetic form of RNA degradation related to PTGS and RNA interference (RNAi) in fungi and animals. Evidence suggests that transgene loci and RNA viruses can generate double-stranded RNAs similar in sequence to the transcribed region of target genes, which then undergo endonucleolytic cleavage to generate small interfering RNAs (siRNA) that promote degradation of cognate RNAs. The silent state in transgenic plants and in Caenorhabditis elegans can spread systemically, implying that mobile silencing signals exist. Neither the chemical nature of these signals nor their exact source in the PTGS pathway is known. Here, we use a positive marker system and real-time monitoring of green fluorescent protein expression to show that large sense, antisense, and double-stranded RNAs as well as double-stranded siRNAs delivered biolistically into plant cells trigger silencing capable of spreading locally and systemically. Systemically silenced leaves show greatly reduced levels of target RNA and accumulate siRNAs, confirming that RNA can induce systemic PTGS. The induced siRNAs represent parts of the target RNA that are outside of the region of homology with the triggering siRNA. Our results imply that siRNAs themselves or intermediates induced by siRNAs could comprise silencing signals and that these signals induce self-amplifying production of siRNAs. PMID:12181491

  3. Oleanolic Acid Induces the Type III Secretion System of Ralstonia solanacearum

    PubMed Central

    Wu, Dousheng; Ding, Wei; Zhang, Yong; Liu, Xuejiao; Yang, Liang

    2015-01-01

    Ralstonia solanacearum, the causal agent of bacterial wilt, can naturally infect a wide range of host plants. The type III secretion system (T3SS) is a major virulence determinant in this bacterium. Studies have shown that plant-derived compounds are able to inhibit or induce the T3SS in some plant pathogenic bacteria, though no specific T3SS inhibitor or inducer has yet been identified in R. solanacearum. In this study, a total of 50 different compounds were screened and almost half of them (22 of 50) significantly inhibited or induced the T3SS expression of R. solanacearum. Based on the strong induction activity on T3SS, the T3SS inducer oleanolic acid (OA) was chosen for further study. We found that OA induced the expression of T3SS through the HrpG-HrpB pathway. Some type III effector genes were induced in T3SS inducing medium supplemented with OA. In addition, OA targeted only the T3SS and did not affect other virulence determinants. Finally, we observed that induction of T3SS by OA accelerated disease progress on tobacco. Overall our results suggest that plant-derived compounds are an abundant source of R. solanacearum T3SS regulators, which could prove useful as tools to interrogate the regulation of this key virulence pathway. PMID:26732647

  4. Characterization of the yeast copper-inducible promoter system in Arabidopsis thaliana

    NASA Technical Reports Server (NTRS)

    Granger, C. L.; Cyr, R. J.

    2001-01-01

    Inducible promoters or gene-switches are used to both spatially and temporally regulate gene expression. Such regulation can provide information concerning the function of a gene in a developmental context as well as avoid potential harmful effects due to overexpression. A gfp construct under the control of a copper-inducible promoter was introduced into Arabidopsis thaliana (L.) Heynh. and the regulatory parameters of this inducible promoter were determined. Here, we describe the time-course of up- and down-regulation of GFP expression in response to copper level, the optimal regulatory levels of copper, and the tissue specificity of expression in three transgenic lines. We conclude that the copper-inducible promoter system may be useful in regulating the time and location of gene expression in A. thaliana.

  5. Installation of Induced Current Measurement Systems in Substations and Analysis of GIC Data during Geomagnetic Storms

    NASA Astrophysics Data System (ADS)

    Choi, Kyu-Cheol; Park, Mi-Young; Ryu, Youngsoo; Hong, Youngsu; Yi, Jong-Hyuk; Park, Sung-Won; Kim, Jae-Hun

    2015-12-01

    Coronal Mass Ejections (CME), which originate from active regions of the Sun's surface, e.g., sunspots, result in geomagnetic storms on Earth. The variation of the Earth's geomagnetic field during such storms induces surface currents that could cause breakdowns in electricity power grids. Hence, it is essential to both monitor Geomagnetically Induced Currents (GICs) in real time and analyze previous GIC data. In 2012, in order to monitor the variation of GICs, the Korean Space Weather Center (KSWC) installed an induced current measurement system at SINGAPYEONG Substation, which is equipped with 765 kV extra-high-voltage transformers. Furthermore, in 2014, two induced current measurement systems were installed on the 345 kV high-voltage transformers at the MIGEUM and SINPOCHEON substations. This paper reports the installation process of the induced current measurement systems at these three substations. Furthermore, it presents the results of both an analysis performed using GIC data measured at the SINGAPYEONG Substation during periods of geomagnetic storms from July 2013 through April 2015 and the comparison between the obtained GIC data and magnetic field variation (dH/dt) data measured at the Icheon geomagnetic observatory.

  6. Constraints to herbivore-induced systemic responses: bidirectional signaling along orthostichies in Nicotiana attenuata.

    PubMed

    Schittko, Ursula; Baldwin, Ian T

    2003-03-01

    We investigated the impact of leaf vascular connections on systemically transmitted herbivore-induced gene expression in Nicotiana attenuata. Although systemic signaling is clearly associated with the plant vascular system, few studies consider vascular architecture when measuring systemically induced defenses. N. attenuata is a plant with dispersed phyllotaxis approximating 3/8 in the rosette stage of growth. We mimicked Manduca sexta herbivory by introducing larval regurgitant to wounds produced with a standardized continuous mechanical wounding and investigated mRNA accumulation of genes. Herbivory in N. attenuata induces the expression of genes coding for a proteinase inhibitor protein (PI), threonine deaminase (TD, EC 4.3.1.19), a luminal-binding protein (BiP), and an alpha-dioxygenase (alpha-DOX). We measured the systemic response of sink leaves when orthostichous (growing at an angular distance of 0 degrees) source leaves were treated, and vice versa, and compared it to the systemic response of leaves growing at the maximum angular distance of 180 degrees. Vascular architecture clearly controlled the intensity of systemic mRNA accumulation within the 4-hr time frame of the experiment. In addition, we found signal translocation to be bidirectional, travelling from source to sink as well as from sink to source leaves, which argues against a phloem-based assimilate-linked signal identity.

  7. A LabVIEW-Based Virtual Instrument System for Laser-Induced Fluorescence Spectroscopy.

    PubMed

    Wu, Qijun; Wang, Lufei; Zu, Lily

    2011-01-01

    We report the design and operation of a Virtual Instrument (VI) system based on LabVIEW 2009 for laser-induced fluorescence experiments. This system achieves synchronous control of equipment and acquisition of real-time fluorescence data communicating with a single computer via GPIB, USB, RS232, and parallel ports. The reported VI system can also accomplish data display, saving, and analysis, and printing the results. The VI system performs sequences of operations automatically, and this system has been successfully applied to obtain the excitation and dispersion spectra of α-methylnaphthalene. The reported VI system opens up new possibilities for researchers and increases the efficiency and precision of experiments. The design and operation of the VI system are described in detail in this paper, and the advantages that this system can provide are highlighted.

  8. A LabVIEW-Based Virtual Instrument System for Laser-Induced Fluorescence Spectroscopy

    PubMed Central

    Wu, Qijun; Wang, Lufei; Zu, Lily

    2011-01-01

    We report the design and operation of a Virtual Instrument (VI) system based on LabVIEW 2009 for laser-induced fluorescence experiments. This system achieves synchronous control of equipment and acquisition of real-time fluorescence data communicating with a single computer via GPIB, USB, RS232, and parallel ports. The reported VI system can also accomplish data display, saving, and analysis, and printing the results. The VI system performs sequences of operations automatically, and this system has been successfully applied to obtain the excitation and dispersion spectra of α-methylnaphthalene. The reported VI system opens up new possibilities for researchers and increases the efficiency and precision of experiments. The design and operation of the VI system are described in detail in this paper, and the advantages that this system can provide are highlighted. PMID:22013388

  9. Syringe-pump-induced fluctuation in all-aqueous microfluidic system implications for flow rate accuracy.

    PubMed

    Li, Zida; Mak, Sze Yi; Sauret, Alban; Shum, Ho Cheung

    2014-02-21

    We report a new method to display the minute fluctuations induced by syringe pumps on microfluidic flows by using a liquid-liquid system with an ultralow interfacial tension. We demonstrate that the stepper motor inside the pump is a source of fluctuations in microfluidic flows by comparing the frequencies of the ripples observed at the interface to that of the pulsation of the stepper motor. We also quantify the fluctuations induced at different flow rates, using syringes of different diameters, and using different syringe pumps with different advancing distances per step. Our work provides a way to predict the frequency of the fluctuation that the driving syringe pump induces on a microfluidic system and suggests that syringe pumps can be a source of fluctuations in microfluidic flows, thus contributing to the polydispersity of the resulting droplets.

  10. Three-pathway electromagnetically induced transparency in coupled-cavity optomechanical system.

    PubMed

    Lei, Fu-Chuan; Gao, Ming; Du, Chunguang; Jing, Qing-Li; Long, Gui-Lu

    2015-05-04

    Recently Qu and Agarwal [Phys. Rev. A 22, 031802 (2013)] found a three-pathway electromagnetically induced absorption (TEIA) phenomenon within a mechanically coupled two-cavity system, where there exist a sharp EIA dip in the broad electromagnetically induced transparency peak in the transmission spectrum. In this work, we study the response of a probe light in a pair of directly coupled microcavities with one mechanical mode. We find that in addition to the sharp TEIA dip within a broad EIT window as found by Qu and Agarwal, three-pathway electromagnetically induced transparency (TEIT) within the broad EIT window could also exist under certain conditions. We give explicit physical explanations and detailed calculations. Our results provide a method for controlling transition between TEIA and TEIT in coupled optomechanical systems, and reveal the multiple pathways interference is versatile for controlling light.

  11. Sleep-active neuron specification and sleep induction require FLP-11 neuropeptides to systemically induce sleep.

    PubMed

    Turek, Michal; Besseling, Judith; Spies, Jan-Philipp; König, Sabine; Bringmann, Henrik

    2016-03-07

    Sleep is an essential behavioral state. It is induced by conserved sleep-active neurons that express GABA. However, little is known about how sleep neuron function is determined and how sleep neurons change physiology and behavior systemically. Here, we investigated sleep in Caenorhabditis elegans, which is induced by the single sleep-active neuron RIS. We found that the transcription factor LIM-6, which specifies GABAergic function, in parallel determines sleep neuron function through the expression of APTF-1, which specifies the expression of FLP-11 neuropeptides. Surprisingly FLP-11, and not GABA, is the major component that determines the sleep-promoting function of RIS. FLP-11 is constantly expressed in RIS. At sleep onset RIS depolarizes and releases FLP-11 to induce a systemic sleep state.

  12. Sleep-active neuron specification and sleep induction require FLP-11 neuropeptides to systemically induce sleep

    PubMed Central

    Turek, Michal; Besseling, Judith; Spies, Jan-Philipp; König, Sabine; Bringmann, Henrik

    2016-01-01

    Sleep is an essential behavioral state. It is induced by conserved sleep-active neurons that express GABA. However, little is known about how sleep neuron function is determined and how sleep neurons change physiology and behavior systemically. Here, we investigated sleep in Caenorhabditis elegans, which is induced by the single sleep-active neuron RIS. We found that the transcription factor LIM-6, which specifies GABAergic function, in parallel determines sleep neuron function through the expression of APTF-1, which specifies the expression of FLP-11 neuropeptides. Surprisingly FLP-11, and not GABA, is the major component that determines the sleep-promoting function of RIS. FLP-11 is constantly expressed in RIS. At sleep onset RIS depolarizes and releases FLP-11 to induce a systemic sleep state. DOI: http://dx.doi.org/10.7554/eLife.12499.001 PMID:26949257

  13. PPS nanoparticles as versatile delivery system to induce systemic and broad mucosal immunity after intranasal administration.

    PubMed

    Stano, Armando; van der Vlies, André J; Martino, Mikael M; Swartz, Melody A; Hubbell, Jeffrey A; Simeoni, Eleonora

    2011-01-17

    Degradable polymer nanoparticles (NPs, 50 nm) based on polypropylene sulfide (PPS) were conjugated to thiolated antigen and adjuvant proteins by reversible disulfide bonds and evaluated in mucosal vaccination. Ovalbumin was used as a model antigen, and antigen-conjugated NPs were administered intranasally in the mouse. We show penetration of nasal mucosae, transit via M cells, and uptake by antigen-presenting cells in the nasal-associated lymphoid tissue. Ovalbumin-conjugated NPs induced cytotoxic T lymphocytic responses in lung and spleen tissues, as well as humoral response in mucosal airways. Co-conjugation of the TLR5 ligand flagellin further enhanced humoral responses in the airways as well as in the distant vaginal and rectal mucosal compartments and induced cellular immune responses with a Th1 bias, in contrast with free flagellin. The PPS NP platform thus appears interesting as a platform for intranasally-administered mucosal vaccination for inducing broad mucosal immunity.

  14. CD-REST: a system for extracting chemical-induced disease relation in literature

    PubMed Central

    Xu, Jun; Wu, Yonghui; Zhang, Yaoyun; Wang, Jingqi; Lee, Hee-Jin; Xu, Hua

    2016-01-01

    Mining chemical-induced disease relations embedded in the vast biomedical literature could facilitate a wide range of computational biomedical applications, such as pharmacovigilance. The BioCreative V organized a Chemical Disease Relation (CDR) Track regarding chemical-induced disease relation extraction from biomedical literature in 2015. We participated in all subtasks of this challenge. In this article, we present our participation system Chemical Disease Relation Extraction SysTem (CD-REST), an end-to-end system for extracting chemical-induced disease relations in biomedical literature. CD-REST consists of two main components: (1) a chemical and disease named entity recognition and normalization module, which employs the Conditional Random Fields algorithm for entity recognition and a Vector Space Model-based approach for normalization; and (2) a relation extraction module that classifies both sentence-level and document-level candidate drug–disease pairs by support vector machines. Our system achieved the best performance on the chemical-induced disease relation extraction subtask in the BioCreative V CDR Track, demonstrating the effectiveness of our proposed machine learning-based approaches for automatic extraction of chemical-induced disease relations in biomedical literature. The CD-REST system provides web services using HTTP POST request. The web services can be accessed from http://clinicalnlptool.com/cdr. The online CD-REST demonstration system is available at http://clinicalnlptool.com/cdr/cdr.html. Database URL: http://clinicalnlptool.com/cdr; http://clinicalnlptool.com/cdr/cdr.html PMID:27016700

  15. Spin-orbit-coupling-induced magnetic heterostructure in the bilayer Bose-Hubbard system

    NASA Astrophysics Data System (ADS)

    Xiong, Bo; Zheng, Jun-hui; Lin, Yu-Ju; Wang, Daw-wei

    2016-12-01

    We investigate the magnetic phases of a bilayer system of ultracold bosons in the presence of Raman-induced spin-orbit (SO) coupling and laser-assisted interlayer tunneling. We consider this bilayer system in the Mott-insulating regime where on-site two-body interactions exceed all the tunneling terms. In such a system there exists a rich set of spin textures including hetero-ferromagnetic, heterochiral magnetic, and chiral magnetic phases with interlayer antiferromagnetic. In particular, the heterochiral magnetic phase induced by SO coupling occurs extremely rarely in solid-state materials. We theoretically analyze the contribution of interlayer ferromagnetic interaction to the formation of these magnetic phases, including interactions that arise from laser-assisted tunneling, stagger "magnetic field," and antisymmetric exchange, i.e., Dzyaloshinskii-Moriya interactions. Finally, we detail an experimental setup that produces the desired interactions in a system of cold alkali-metal atoms.

  16. CRH engagement of the locus coeruleus noradrenergic system mediates stress-induced anxiety

    PubMed Central

    McCall, Jordan G.; Al-Hasani, Ream; Siuda, Edward R.; Hong, Daniel Y.; Norris, Aaron J.; Ford, Christopher P.; Bruchas, Michael R.

    2015-01-01

    Summary The locus coeruleus noradrenergic (LC-NE) system is one of the first systems engaged following a stressful event. While numerous groups have demonstrated that LC-NE neurons are activated by many different stressors, the underlying neural circuitry and the role of this activity in generating stress-induced anxiety has not been elucidated. Using a combination of in vivo chemogenetics, optogenetics, and retrograde tracing we determine that increased tonic activity of the LC-NE system is necessary and sufficient for stress-induced anxiety and aversion. Selective inhibition of LC-NE neurons during stress prevents subsequent anxiety-like behavior. Exogenously increasing tonic, but not phasic, activity of LC-NE neurons is alone sufficient for anxiety-like and aversive behavior. Furthermore, endogenous corticotropin releasing hormone+ (CRH+) LC inputs from the amygdala increase tonic LC activity, inducing anxiety-like behaviors. These studies position the LC-NE system as a critical mediator of acute stress-induced anxiety and offer a potential intervention for preventing stress-related affective disorders. PMID:26212712

  17. Role of endocannabinoid and glutamatergic systems in DOI-induced head-twitch response in mice.

    PubMed

    Egashira, Nobuaki; Shirakawa, Atsunori; Okuno, Ryoko; Mishima, Kenichi; Iwasaki, Katsunori; Oishi, Ryozo; Fujiwara, Michihiro

    2011-07-01

    We previously reported that systemic administration of the endocannabinoid anandamide inhibited the head-twitches induced by the hallucinogenic drug 2,5-dimethoxy-4-iodoamphetamine (DOI) in mice, which is mediated via the activation of 5-HT(2A) receptors. Endocannabinoid and glutamatergic systems have been suggested to modulate the function of 5-HT(2A) receptors. In the present study, we further investigated the role of endocannabinoid and glutamatergic systems in DOI-induced head-twitch response in mice. An anandamide transport inhibitor AM404 (0.3-3mg/kg, i.p.), a fatty acid amide hydrolase inhibitor URB597 (0.1-10mg/kg, i.p.), a glutamate release inhibitor riluzole (0.3 and 1mg/kg, i.p.), a natural glutamate analog l-glutamylethylamide (theanine, 1 and 3mg/kg, p.o.) and an α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptor antagonist NBQX (0.01-0.3mg/kg, i.p.) significantly inhibited DOI-induced head-twitch response. The AMPA receptor positive modulator aniracetam (30 or 100mg/kg, p.o.) reversed inhibition of head-twitch response by NBQX and URB597. These findings indicated that endocannabinoid and glutamatergic systems participate in the mechanism of action of DOI to induce head-twitch response.

  18. Experimental distinction of Autler-Townes splitting from electromagnetically induced transparency using coupled mechanical oscillators system

    PubMed Central

    Liu, Jingliang; Yang, Hujiang; Wang, Chuan; Xu, Kun; Xiao, Jinghua

    2016-01-01

    Here we experimentally demonstrated the electromagnetically induced transparency (EIT) and Autler-Townes splitting (ATS) effects in mechanical coupled pendulums. The analogue of EIT and ATS has been studied in mechanical systems and the intrinsic physics between these two phenomena are also been discussed. Exploiting the Akaike Information Criterion, we discern the ATS effect from EIT effect in our experimental results. PMID:26751738

  19. CRH Engagement of the Locus Coeruleus Noradrenergic System Mediates Stress-Induced Anxiety.

    PubMed

    McCall, Jordan G; Al-Hasani, Ream; Siuda, Edward R; Hong, Daniel Y; Norris, Aaron J; Ford, Christopher P; Bruchas, Michael R

    2015-08-05

    The locus coeruleus noradrenergic (LC-NE) system is one of the first systems engaged following a stressful event. While numerous groups have demonstrated that LC-NE neurons are activated by many different stressors, the underlying neural circuitry and the role of this activity in generating stress-induced anxiety has not been elucidated. Using a combination of in vivo chemogenetics, optogenetics, and retrograde tracing, we determine that increased tonic activity of the LC-NE system is necessary and sufficient for stress-induced anxiety and aversion. Selective inhibition of LC-NE neurons during stress prevents subsequent anxiety-like behavior. Exogenously increasing tonic, but not phasic, activity of LC-NE neurons is alone sufficient for anxiety-like and aversive behavior. Furthermore, endogenous corticotropin-releasing hormone(+) (CRH(+)) LC inputs from the amygdala increase tonic LC activity, inducing anxiety-like behaviors. These studies position the LC-NE system as a critical mediator of acute stress-induced anxiety and offer a potential intervention for preventing stress-related affective disorders.

  20. AIR PARTICULATE POLLUTION EXPOSURE INDUCES SYSTEMIC OXIDATIVE STRESS IN HEALTHY MICE

    EPA Science Inventory

    Air particulate pollution exposure induces systemic oxidative stress in healthy mice

    Elizabeth S Roberts1 and Kevin L Dreher2. 1 College or Veterinary Medicine, NC State University, Raleigh, NC , 2US Environmental Protection Agency, NHEERL, RTP, NC

    Epidemiological s...

  1. Glycerol-3-phosphate is a critical mobile inducer of systemic immunity in plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glycerol-3-phosphate (G3P) is an important metabolite that contributes to the growth and disease-related physiologies of prokaryotes, plants, animals and humans alike. Here we show that G3P serves as the inducer of an important form of broad-spectrum immunity in plants, termed systemic acquired resi...

  2. A Doxycycline-Inducible System for Genetic Correction of iPSC Disease Models.

    PubMed

    Sim, Xiuli; Cardenas-Diaz, Fabian L; French, Deborah L; Gadue, Paul

    2016-01-01

    Patient-derived induced pluripotent stem cells (iPSCs) are valuable tools for the study of developmental biology and disease modeling. In both applications, genetic correction of patient iPSCs is a powerful method to understand the specific contribution of a gene(s) in development or diseased state(s). Here, we describe a protocol for the targeted integration of a doxycycline-inducible transgene expression system in a safe harbor site in iPSCs. Our gene targeting strategy uses zinc finger nucleases (ZFNs) to enhance homologous recombination at the AAVS1 safe harbor locus, thus increasing the efficiency of the site-specific integration of the two targeting vectors that make up the doxycycline-inducible system. Importantly, the use of dual-drug selection in our system increases the efficiency of positive selection for double-targeted clones to >50 %, permitting a less laborious screening process. If desired, this protocol can also be adapted to allow the use of tissue-specific promoters to drive gene expression instead of the doxycycline-inducible promoter (TRE). Additionally, this protocol is also compatible with the use of Transcription-Activator-Like Effector Nucleases (TALENs) or Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas9 system in place of ZFNs.

  3. EFFECTS OF SYSTEMIC NEUTROPHIL DEPLETION ON LPS-INDUCED AIRWAY DISEASE

    EPA Science Inventory

    Effects of Systemic Neutrophil Depletion on LPS-induced Airway Disease
    Jordan D. Savov, Stephen H. Gavett*, David M. Brass, Daniel L. Costa*, David A. Schwartz
    Pulmonary and Critical Care Division, Dept of Medicine ? Duke University Medical Center
    * National Health and E...

  4. Thermodynamic studies of induced antiferroelectric phases in chiral and racemic systems

    NASA Astrophysics Data System (ADS)

    Filipowicz, M.; Kula, P.; Czuprynski, Krzysztof

    2004-09-01

    Bi- and multicomponent mixtures consisted of two groups of synclinic chiral esters: first one with a partially fluorinated terminal chain and the second one with hydrogenated terminal chain have been used for investigations. For some systems the induction of the anticlinic smectic CA* phase was observed. Enthalpies of the phase transitions for the systems with induced smectic CA phase upon compositions and specific heat were measured by DSC method.

  5. Calculation of the induced currents and forces for a hybrid magnetic levitation system

    SciTech Connect

    Albertz, D.; Dappen, S.; Henneberger, G.

    1997-03-01

    This paper presents the calculation of the induced currents and forces for a 3D non-linear eddy current field problem with ferromagnetic moving conductors. The {rvec A}, V-{rvec A} formulation is used in combination with four different gauging methods to stabilize the solution process. To consider non-rectangular shapes of geometries tetrahedral elements were employed. The computation procedure is applied to a hybrid magnetic levitation system of a contactless and frictionless conveyance system.

  6. Computer circuit analysis of induced currents in the MFTF-B magnet system

    SciTech Connect

    Magnuson, G.D.; Woods, E.L.

    1981-10-23

    An analysis was made of the induced current behavior of the MFTF-B magnet system. Although the magnet system consists of 22 coils, because of its symmetry we considered only 11 coils in the analysis. Various combinations of the coils were dumped either singly or in groups, with the current behavior in all magnets calculated as a function of time after initiation of the dump.

  7. Numerical results on noise-induced dynamics in the subthreshold regime for thermoacoustic systems

    NASA Astrophysics Data System (ADS)

    Gupta, Vikrant; Saurabh, Aditya; Paschereit, Christian Oliver; Kabiraj, Lipika

    2017-03-01

    Thermoacoustic instability is a serious issue in practical combustion systems. Such systems are inherently noisy, and hence the influence of noise on the dynamics of thermoacoustic instability is an aspect of practical importance. The present work is motivated by a recent report on the experimental observation of coherence resonance, or noise-induced coherence with a resonance-like dependence on the noise intensity as the system approaches the stability margin, for a prototypical premixed laminar flame combustor (Kabiraj et al., Phys. Rev. E, 4 (2015)). We numerically investigate representative thermoacoustic models for such noise-induced dynamics. Similar to the experiments, we study variation in system dynamics in response to variations in the noise intensity and in a critical control parameter as the systems approach their stability margins. The qualitative match identified between experimental results and observations in the representative models investigated here confirms that coherence resonance is a feature of thermoacoustic systems. We also extend the experimental results, which were limited to the case of subcritical Hopf bifurcation, to the case of supercritical Hopf bifurcation. We identify that the phenomenon has qualitative differences for the systems undergoing transition via subcritical and supercritical Hopf bifurcations. Two important practical implications are associated with the findings. Firstly, the increase in noise-induced coherence as the system approaches the onset of thermoacoustic instability can be considered as a precursor to the instability. Secondly, the dependence of noise-induced dynamics on the bifurcation type can be utilised to distinguish between subcritical and supercritical bifurcation prior to the onset of the instability.

  8. Periodontal disease exacerbates systemic ovariectomy-induced bone loss in mice.

    PubMed

    Anbinder, Ana Lia; Moraes, Renata M; Lima, Gabriela M G; Oliveira, Felipe E; Campos, Débora R C; Rossoni, Rodnei D; Oliveira, Luciane D; Junqueira, Juliana C; Ma, Yun; Elefteriou, Florent

    2016-02-01

    Periodontal pathogens and/or inflammatory products from periodontitis participate in the development or progression of systemic diseases. In this context, periodontitis acts as a modifying factor to systemic health, including diabetes and cardiovascular diseases. Osteoporosis is an increasingly prevalent condition in our aging population and considered a risk factor for periodontal disease, but the effect of periodontitis on systemic bone homeostasis is unknown. We thus evaluated the effects of experimental periodontitis (EP) on systemic bone loss and the influence of estrogen deficiency in this context, using a mouse model of combined periodontitis and osteoporosis. Experimental periodontitis (EP) was induced by a ligature insertion around the mandibular first molars and Porphyromonas gingivalis infection. Three-dimensional microcomputed tomographic analyses performed 48days following infection revealed that EP and ovariectomy (OVX) induced a significantly higher femoral and mandibular bone loss compared to EP or OVX alone. EP alone did not induce systemic bone loss. In addition, the EP+OVX and EP groups showed significantly higher levels of tumor necrosis factor (TNF)-α than OVX and control groups at end point. These results suggest that periodontitis could be a risk factor for systemic bone loss, especially in post-menopausal women, and warrant further clinical investigations to confirm this association and propose adapted prophylactic and curative therapies.

  9. Efficient calculation of many-body induced electrostatics in molecular systems.

    PubMed

    McLaughlin, Keith; Cioce, Christian R; Pham, Tony; Belof, Jonathan L; Space, Brian

    2013-11-14

    Potential energy functions including many-body polarization are in widespread use in simulations of aqueous and biological systems, metal-organics, molecular clusters, and other systems where electronically induced redistribution of charge among local atomic sites is of importance. The polarization interactions, treated here via the methods of Thole and Applequist, while long-ranged, can be computed for moderate-sized periodic systems with extremely high accuracy by extending Ewald summation to the induced fields as demonstrated by Nymand, Sala, and others. These full Ewald polarization calculations, however, are expensive and often limited to very small systems, particularly in Monte Carlo simulations, which may require energy evaluation over several hundred-thousand configurations. For such situations, it shall be shown that sufficiently accurate computation of the polarization energy can be produced in a fraction of the central processing unit (CPU) time by neglecting the long-range extension to the induced fields while applying the long-range treatments of Ewald or Wolf to the static fields; these methods, denoted Ewald E-Static and Wolf E-Static (WES), respectively, provide an effective means to obtain polarization energies for intermediate and large systems including those with several thousand polarizable sites in a fraction of the CPU time. Furthermore, we shall demonstrate a means to optimize the damping for WES calculations via extrapolation from smaller trial systems.

  10. A theoretical analysis of the feasibility of a singularity-induced micro-electroporation system.

    PubMed

    Troszak, Gregory D; Rubinsky, Boris

    2011-04-08

    Electroporation, the permeabilization of the cell membrane lipid bilayer due to a pulsed electric field, has important implications in the biotechnology, medicine, and food industries. Traditional macro and micro-electroporation devices have facing electrodes, and require significant potential differences to induce electroporation. The goal of this theoretical study is to investigate the feasibility of singularity-induced micro-electroporation; an electroporation configuration aimed at minimizing the potential differences required to induce electroporation by separating adjacent electrodes with a nanometer-scale insulator. In particular, this study aims to understand the effect of (1) insulator thickness and (2) electrode kinetics on electric field distributions in the singularity-induced micro-electroporation configuration. A non-dimensional primary current distribution model of the micro-electroporation channel shows that while increasing insulator thickness results in smaller electric field magnitudes, electroporation can still be performed with insulators thick enough to be made with microfabrication techniques. Furthermore, a secondary current distribution model of the singularity-induced micro-electroporation configuration with inert platinum electrodes and water electrolyte indicates that electrode kinetics do not inhibit charge transfer to the extent that prohibitively large potential differences are required to perform electroporation. These results indicate that singularity-induced micro-electroporation could be used to develop an electroporation system that consumes minimal power, making it suitable for remote applications such as the sterilization of water and other liquids.

  11. Low-dose effect of ethanol on locomotor activity induced by activation of the mesolimbic system.

    PubMed

    Milton, G V; Randall, P K; Erickson, C K

    1995-06-01

    Four experiments were designed to study the ability of 0.5 g/kg ethanol (EtOH) intraperitoneally to modify locomotor activity induced by drugs that interact with different sites in the mesolimbic system (MLS) of male Sprague-Dawley rats. Locomotor activity was measured in a doughnut-shaped circular arena after various treatments. EtOH alone did not alter locomotor activity in any of the experiments. Amphetamine (AMP, intraperitoneally or intraaccumbens) increased locomotor activity in a dose-dependent manner, and the presence of EtOH attenuated AMP-induced locomotor activity. Bilateral infusion of GABAA antagonist picrotoxin (PIC) into the ventral tegmental area also increased locomotor activity in a dose-dependent manner, and the presence of EtOH attenuated PIC-induced locomotor activity. On the other hand, the interaction between bilateral infusion of mu-receptor agonist Tyr-D-Ala-Gly-NMe-Phe-Gly-ol (DAGO) and EtOH on locomotor activity is complex. The highest dose of DAGO that significantly increased locomotor activity was not affected by the presence of EtOH. But, with lower doses of DAGO that either had no effect or a small increase in locomotor activity, the combination of EtOH and DAGO increased and attenuated locomotor activity, respectively. Results from this study support our hypothesis that a low dose of EtOH that does not modify behavior can interact with neurotransmitter systems in the brain and modify drug-induced locomotor activity. Modification of this drug-induced locomotor activity by a low dose of EtOH is dependent on the rate of ongoing locomotor behavior induced by drug and the neurotransmitter substrate that the drug modified to induce locomotor behavior.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. Regulation of Diet-Induced Adipose Tissue and Systemic Inflammation by Salicylates and Pioglitazone

    PubMed Central

    Kamei, Nozomu; Shimada, Takeshi; Liu, Libin; Moore, Kristin; Woo, Ju Rang; Shoelson, Steven E.; Lee, Jongsoon

    2013-01-01

    It is increasingly accepted that chronic inflammation participates in obesity-induced insulin resistance and type 2 diabetes (T2D). Salicylates and thiazolidinediones (TZDs) both have anti-inflammatory and anti-hyperglycemic properties. The present study compared the effects of these drugs on obesity-induced inflammation in adipose tissue (AT) and AT macrophages (ATMs), as well as the metabolic and immunological phenotypes of the animal models. Both drugs improved high fat diet (HFD)-induced insulin resistance. However, salicylates did not affect AT and ATM inflammation, whereas Pioglitazone improved these parameters. Interestingly, HFD and the drug treatments all modulated systemic inflammation as assessed by changes in circulating immune cell numbers and activation states. HFD increased the numbers of circulating white blood cells, neutrophils, and a pro-inflammatory monocyte subpopulation (Ly6Chi), whereas salicylates and Pioglitazone normalized these cell numbers. The drug treatments also decreased circulating lymphocyte numbers. These data suggest that obesity induces systemic inflammation by regulating circulating immune cell phenotypes and that anti-diabetic interventions suppress systemic inflammation by normalizing circulating immune phenotypes. PMID:24376593

  13. Compositional trends of radiation-induced effects in ternary systems of chalcogenide glasses

    NASA Astrophysics Data System (ADS)

    Kovalskiy, A.

    2003-01-01

    The effect of gamma-irradiation on the optical transmittance spectra of pseudobinary stoichiometric and non-stoichiometric cuts of ternary systems of chalcogenide glasses was studied. The application of chemical-bond approach is proposed to explain the features of compositional dependencies of radiation-induced effects in these materials. It is shown that free volume concept must be taken into consideration at the presence of different radiation-sensitive structural units. The creation processes of coordination defects connected with the formation of free volume and coupled with the capability of the constituent atoms to passivation are the main factors determining the magnitude of the radiation-induced effects in chalcogenide glasses.

  14. Aerodynamic design of a Coanda induced force and thruster anti-torque system

    NASA Technical Reports Server (NTRS)

    Velkoff, Henry R.; Tung, Chee

    1991-01-01

    A general method of analysis of the external and internal aerodynamics of a generic Coanda induced circulation anti-torque system is presented. The technique gives moment about the yaw axis and download induced on the boom as well as the force developed by an aft jet. The external flows including downwash, wake swirl and the boom circulation are considered. The internal flow and losses through the duct, fan, blown slots, cascades and nozzle are considered on a step-by-step basis. Limited comparison is made with open data where available.

  15. Numerical analysis of mixing by electrothermal induced flow in microfluidic systems

    PubMed Central

    Feng, J. J.; Krishnamoorthy, S.; Sundaram, S.

    2007-01-01

    An electrothermal flow induced chaotic mixing in microfluidic systems is studied analytically and numerically. The flow is induced due to the Coulombic and dielectric forces arising from the variation of the dielectric properties with respect to the temperature in the presence of an electric field. The numerical model is validated using an analytical solution derived for basic flow patterns in a simplified geometry. The computational model has been used to illustrate the mixing in microcavity and T-sensor constructs. The simulations predict the chaotic nature of the mixing process, where the material interface evolution shows exponential growth. PMID:19693379

  16. Oxcarbazepine-induced drug rash with eosinophilia and systemic symptoms syndrome presenting as exfoliative dermatitis.

    PubMed

    Saha, Mahimanjan; Gorai, Surajit; Madhab, Vaswatee

    2016-01-01

    Drug rash with eosinophilia and systemic symptoms (DRESS) syndrome is a type of severe adverse cutaneous drug reaction characterized by fever, skin eruption, hematological abnormalities, and internal organ involvement. Although anticonvulsant drugs are mainly implicated in DRESS, newer anticonvulsants such as oxcarbazepine-induced definite cases of DRESS syndrome are rare and oxcarbazepine-induced DRESS syndrome presenting as exfoliative dermatitis is even rarer. We report a case of a 35-year-old male who developed DRESS syndrome presenting as exfoliative dermatitis after taking oxcarbazepine for 3 weeks.

  17. Hopf-bifurcation-delay-induced bursting patterns in a modified circuit system

    NASA Astrophysics Data System (ADS)

    Han, Xiujing; Xia, Fubing; Ji, Peng; Bi, Qinsheng; Kurths, Jürgen

    2016-07-01

    Based on Hopf bifurcation delay, we present two novel delay-induced bursting patterns in a modified van der Pol-Duffing circuit system. These delay-induced bursting patterns are classified as compound "delayed supHopf/fold cycle-subHopf/supHopf" bursting and "subHopf/supHopf" bursting via "delayed supHopf/supHopf" hysteresis loop, respectively. Our results show that Hopf bifurcation delay plays a decisive role in the generation of these two bursting patterns, which enriches the routes to bursting and deepens the understanding of underlying mechanisms of bursting.

  18. Quantification of MDL-induced signal degradation in MIMO-OFDM mode-division multiplexing systems.

    PubMed

    Tian, Yu; Li, Juhao; Zhu, Paikun; Wu, Zhongying; Chen, Yuanxiang; He, Yongqi; Chen, Zhangyuan

    2016-08-22

    Mode-division multiplexing (MDM) transmission over few-mode optical fiber has emerged as a promising technology to enhance transmission capacity, in which multiple-input-multiple-output (MIMO) digital signal processing (DSP) after coherent detection is used to demultiplex the signals. Compared with conventional single-mode systems, MIMO-MDM systems suffer non-recoverable signal degradation induced by mode-dependent loss (MDL). In this paper, the MDL-induced signal degradation in orthogonal-frequency-division-multiplexing (OFDM) MDM systems is theoretically quantified in terms of mode-average error vector magnitude (EVM) through frequency domain norm analysis. A novel scalar MDL metric is proposed considering the probability distribution of the practical MDM input signals, and a closed-form expression for EVM measured after zero-force (ZF) MIMO equalization is derived. Simulation results show that the EVM estimations utilizing the novel MDL metric remain unbiased for unrepeated links. For a 6 × 100 km 20-mode MDM transmission system, the estimation accuracy is improved by more than 90% compared with that utilizing traditional condition number (CN) based MDL metric. The proposed MDL metric can be used to predict the MDL-induced SNR penalty in a theoretical manner, which will be beneficial for the design of practical MIMO-MDM systems.

  19. Patient inducement, provider priorities, and resource allocation in public mental health systems.

    PubMed

    Sinaiko, Anna D; McGuire, Thomas G

    2006-12-01

    Public mental health systems are increasingly facing demands from the criminal justice system and social services agencies to provide services and support in cases in which mental illness contributes to crime, homelessness, or poverty. In this article we analyze how policies from outside public mental health systems affect resource allocation within these systems, using examples from criminal justice. These policies use two types of mechanisms: inducing patients to consume treatment (by offering rewards or imposing penalties) and inducing clinicians to provide treatment (by creating priorities). We propose a classification of these social policies based on whether they affect demand through rewards or penalties or supply through priorities. We then relate the classification to data on patients treated in public systems to evaluate the current prevalence and potential for growth in these outside demands. These inducements impose a set of nonobvious costs on other patients who are not targeted by the policies. Furthermore, they create incentives for both patients and providers to modify their behavior in order to take advantage of rewards, avoid penalties, or better compete for resources with prioritized patients. We consider some policy implications for avoiding unintended consequences of these policies.

  20. Study on a gas transport system based on thermal induced flow

    NASA Astrophysics Data System (ADS)

    Matsumoto, Hiroaki; Mihara, Kai; Yamagishi, Daigo; Morokuma, Takayuki

    2016-11-01

    In this study, the performance of a rarefied gas transport system which works by thermal induced flow was studied experimentally. The driving force of the pump system presented in this study is thermal creep flow around the edge of a small circular plate. The thermal induced flow is generated by irradiating the plates, which are colored black on one side and white on the other. The system was constructed by arranging a series of such plates in a glass pipe which was connected to two vessels and irradiated with an infrared lamp. It was observed that the ratio of pressures in the two vessels was about 96% when the temperature difference between the black and white surfaces of the plates was about 40 °C.

  1. An Assessment of Remote Visual Testing System Capabilities for the Detection of Service Induced Cracking

    SciTech Connect

    Anderson, Michael T.; Cumblidge, Stephen E.; Doctor, Steven R.

    2005-09-01

    Remote visual testing is typically employed to ascertain the condition of materials in components that are inaccessible for direct examination. In the power and petrochemical industries, remote visual testing is used to assess whether service-related degradation is being manifested that, if left unchecked, may eventually impair the structural reliability of a component. Several codes and standards require that visual examinations be periodically conducted. Many of these inspections must be performed remotely due to harsh environments or design geometries of the subject components. This paper describes the attributes and limitations of remote visual testing, performance demonstration standards for camera systems, typical dimensions for service-induced cracking phenomena, and an assessment of the reliability of remote video camera systems at finding cracks. Because many forms of service-induced cracks have very small crack opening dimensions, the reliability of remote visual testing may not be adequate to ensure component integrity, given the capabilities of current camera systems and application practices.

  2. Plasmonic electromagnetically induced transparency in metallic nanoparticle-quantum dot hybrid systems

    NASA Astrophysics Data System (ADS)

    Hatef, Ali; Sadeghi, Seyed M.; Singh, Mahi R.

    2012-02-01

    We study the variation of the energy absorption rate in a hybrid semiconductor quantum dot-metallic nanoparticle system doped in a photonic crystal. The quantum dot is taken as a three-level V-configuration system and is driven by two applied fields (probe and control). We consider that one of the excitonic resonance frequencies is near to the plasmonic resonance frequency of the metallic nanoparticle, and is driven by the probe field. The other excitonic resonance frequency is far from both the plasmonic resonance frequency and the photonic bandgap edge, and is driven by the control field. In the absence of the photonic crystal we found that the system supports three excitonic-induced transparencies in the energy absorption spectrum of the metallic nanoparticle. We show that the photonic crystal allows us to manipulate the frequencies of such excitonic-induced transparencies and the amplitude of the energy absorption rate.

  3. Interleukin-6 and lung inflammation: evidence for a causative role in inducing respiratory system resistance increments.

    PubMed

    Rubini, Alessandro

    2013-10-01

    Interleukin-6 is a multifunctional cytokine that has been shown to be increased in some pathological conditions involving the respiratory system such as those experimentally induced in animals or spontaneously occurring in humans. Experimental data demonstrating that interleukin-6 plays a significant role in commonly occurring respiratory system inflammatory diseases are reviewed here. Those diseases, i.e. asthma and chronic obstructive pulmonary disease, are characterised by mechanical derangements of the respiratory system, for the most part due to increased elastance and airway resistance. Recent findings showing that interleukin-6 has a causative role in determining an increase in airway resistance are reviewed. The end-inflation occlusion method was used to study the mechanical properties of the respiratory system before and after interleukin-6 administration. The cytokine was shown to induce significant, dose-dependent increments in both the resistive pressure dissipation due to frictional forces opposing the airflow in the airway (ohmic resistance) and the additional resistive pressure dissipation due to the visco-elastic properties of the system, i.e. stress relaxation (visco-elastic resistance). There were no alterations in respiratory system elastance. Even when administered to healthy mammals, interleukin-6 determines a significant effect on respiratory system resistance causing an increase in the mechanical work of breathing during inspiration. IL-6 hypothetically plays an active role in the pathogenesis of respiratory system diseases and the mechanisms that may be involved are discussed here.

  4. Efficient in vivo regulation of cytidine deaminase expression in the haematopoietic system using a doxycycline-inducible lentiviral vector system.

    PubMed

    Lachmann, N; Brennig, S; Pfaff, N; Schermeier, H; Dahlmann, J; Phaltane, R; Gruh, I; Modlich, U; Schambach, A; Baum, C; Moritz, T

    2013-03-01

    Regulated transgene expression may reduce transgene-specific and genotoxic risks associated with gene therapy. To prove this concept, we have investigated the suitability of doxycycline (Dox)-inducible human cytidine deaminase (hCDD) overexpression from lentiviral vectors to mediate effective myeloprotection while circumventing the lymphotoxicity observed with constitutive CDD activity. Rapid Dox-mediated transgene induction associated with a 6-17-fold increase in drug resistance was observed in 32D and primary murine bone marrow (BM) cells. Moreover, robust Dox-regulated transgene expression in the entire haematopoietic system was demonstrated for primary and secondary recipients of hCDD-transduced R26-M2rtTA transgenic BM cells. Furthermore, mice were significantly protected from myelosuppressive chemotherapy as evidenced by accelerated recovery of granulocytes (1.9±0.6 vs 1.3±0.3, P=0.034) and platelets (883±194 vs 584±160 10(3) per μl, P=0.011). Minimal transgene expression in the non-induced state and no overt cellular toxicities including lymphotoxicity were detected. Thus, using a relevant murine transplant model our data provide conclusive evidence that drug-resistance transgenes can be expressed in a regulated fashion in the lymphohaematopoietic system, and that Dox-inducible systems may be used to reduce myelotoxic side effect of anticancer chemotherapy or to avoid side effects of high constitutive transgene expression.

  5. Effect of bentonite on radiation induced dissolution of UO2 in an aqueous system

    NASA Astrophysics Data System (ADS)

    Barreiro Fidalgo, Alexandre; Sundin, Sara; Jonsson, Mats

    2014-04-01

    In order to elucidate the impact of bentonite on the process of radiation induced oxidative dissolution of UO2 in an aqueous system, the dissolution of U(VI) and consumption of H2O2 over time has been studied. In addition, γ-irradiation experiments were performed to study a more relevant and complex system, serving as a comparison with the previously stated system. In both cases, the experiments revealed that the presence of bentonite in water could either delay or prevent in part the release of uranium to the environment. The cause is mainly attributed to the scavenging of radiolytic oxidants rather than to the adsorption of uranium onto bentonite.

  6. Flowing recirculated-water system for inducing laboratory spawning of sea lampreys

    USGS Publications Warehouse

    Fredricks, Kim T.; Seelye, James G.

    1995-01-01

    We describe a water-recirculating system for inducing spawning of sea lampreys (Petromyzon marinus) held under laboratory conditions. Water temperature in the system was gradually increased to and maintained at 18 +/- 2 degrees C, the optimal temperature for spawning. About 10% freshwater was added daily to prevent buildup of waste products. Sea lampreys were provided substrate (approximately 3-6 cm in diameter) to build nests, and a water velocity of 0.2-0.3 m/s was maintained with an electric trolling motor. Sea lampreys held in this system exhibited characteristic spawning behavior. Prolarvae produced from artificial fertilization of gametes developed according to the standard timeline.

  7. Identical synchronization of chaotic secure communication systems with channel induced coherence resonance

    NASA Astrophysics Data System (ADS)

    Sepantaie, Marc M.; Namazi, Nader M.; Sepantaie, Amir M.

    2016-05-01

    This paper is devoted to addressing the synchronization, and detection of random binary data exposed to inherent channel variations existing in Free Space Optical (FSO) communication systems. This task is achieved by utilizing the identical synchronization methodology of Lorenz chaotic communication system, and its synergetic interaction in adversities imposed by the FSO channel. Moreover, the Lorenz system has been analyzed, and revealed to induce Stochastic Resonance (SR) once exposed to Additive White Gaussian Noise (AWGN). In particular, the resiliency of the Lorenz chaotic system, in light of channel adversities, has been attributed to the success of the proposed communication system. Furthermore, this paper advocates the use of Haar wavelet transform for enhanced detection capability of the proposed chaotic communication system, which utilizes Chaotic Parameter Modulation (CPM) technique for means of transmission.

  8. Inactivated Influenza Vaccine That Provides Rapid, Innate-Immune-System-Mediated Protection and Subsequent Long-Term Adaptive Immunity

    PubMed Central

    Wong, Chinn Yi; Mifsud, Edin J.; Edenborough, Kathryn M.; Sekiya, Toshiki; Tan, Amabel C. L.; Mercuri, Francesca; Rockman, Steve; Chen, Weisan; Turner, Stephen J.; Doherty, Peter C.; Kelso, Anne; Brown, Lorena E.; Jackson, David C.

    2015-01-01

    ABSTRACT The continual threat to global health posed by influenza has led to increased efforts to improve the effectiveness of influenza vaccines for use in epidemics and pandemics. We show in this study that formulation of a low dose of inactivated detergent-split influenza vaccine with a Toll-like receptor 2 (TLR2) agonist-based lipopeptide adjuvant (R4Pam2Cys) provides (i) immediate, antigen-independent immunity mediated by the innate immune system and (ii) significant enhancement of antigen-dependent immunity which exhibits an increased breadth of effector function. Intranasal administration of mice with vaccine formulated with R4Pam2Cys but not vaccine alone provides protection against both homologous and serologically distinct (heterologous) viral strains within a day of administration. Vaccination in the presence of R4Pam2Cys subsequently also induces high levels of systemic IgM, IgG1, and IgG2b antibodies and pulmonary IgA antibodies that inhibit hemagglutination (HA) and neuraminidase (NA) activities of homologous but not heterologous virus. Improved primary virus nucleoprotein (NP)-specific CD8+ T cell responses are also induced by the use of R4Pam2Cys and are associated with robust recall responses to provide heterologous protection. These protective effects are demonstrated in wild-type and antibody-deficient animals but not in those depleted of CD8+ T cells. Using a contact-dependent virus transmission model, we also found that heterologous virus transmission from vaccinated mice to naive mice is significantly reduced. These results demonstrate the potential of adding a TLR2 agonist to an existing seasonal influenza vaccine to improve its utility by inducing immediate short-term nonspecific antiviral protection and also antigen-specific responses to provide homologous and heterologous immunity. PMID:26507227

  9. Drug-induced systemic lupus erythematosus in a child after 3 years of treatment with carbamazepine.

    PubMed

    Molina-Ruiz, Ana María; Lasanta, Begoña; Barcia, Ana; Pérez-Vega, Elisa; Requena, Luis

    2017-02-01

    Drug-induced lupus erythematosus (DILE) is a less severe variant of systemic lupus erythematosus (SLE) that generally resolves within weeks or months after the withdrawal of the implicated drug. DILE is unusual during childhood, with the most frequent age of presentation being at 50-70 years of age. Among different drugs, most commonly procainamide and hydralazine have been implicated as a cause of DILE. However carbamazepine (CBZ) is considered a low-risk drug and very few cases have been reported in children. We describe the case of CBZ-induced SLE in a 9-year-old girl following 3 years of CBZ therapy. This case report shows that drug-induced SLE is an important side-effect to be considered, even after long-term treatment with CBZ, and also during childhood.

  10. Disorder-induced bound states within an adatom-quantum wire system

    NASA Astrophysics Data System (ADS)

    Magnetta, Bradley; Ordonez, Gonzalo

    2014-03-01

    Bound states induced by disorder are theoretically observed within a quantum wire and adatom system. The quantum wire is modeled as an array of quantum wells with random energies and exhibits Anderson Localization. By varying the energy of our adatom and adjusting the tunneling strength between the adatom and the quantum wire we observe disorder-induced bound states between the the adatom and its attached point. The characteristics of these disorder-induced bound states are greatly influenced by the site of interest on the quantum wire. Utilizing random quantum wires and disordered superlattices to produce bound states may offer flexibility in fabrication as well as provide grounds for energy transmission in photovoltaics.

  11. Interleukin-6 and Lung Inflammation: Evidences of A Causing Role in Inducing Respiratory System Resistance Increments.

    PubMed

    Rubini, Alessandro

    2013-07-10

    Interleukin-6 has been shown to be increased in various pathological conditions involving the lungs, both experimentally induced in animals, or spontaneously occurring in humans. Experimental data demonstrating a significant role of interleukin-6 in commonly occurring respiratory system inflammatory diseases are reviewed. These diseases, i.e. asthma and chronic obstructive pulmonary disease, are characterised by respiratory system mechanical derangement, most of all because increased elastance and airway resistance. Recent findings showing a causative role of interleukin-6 in determining an airway resistance increment are reviewed. By applying the end-inflation occlusion method to study respiratory system mechanical properties before and after interleukin-6 administration, it was shown that this cytokine induced significant increments in both the resistive pressure dissipation due to frictional forces opposing the airflow in the airway (ohmic resistance), and in the additional resistive pressure dissipation due to the visco-elastic properties of the system, i.e. stress relaxation (visco-elastic resistance). A dose-dependent effect was also demonstrated. No effects were instead detected on respiratory system elastance. Even solely administrated in healthy mammals, interleukin-6 exhibits a significant effect on respiratory system resistances, leading to increased inspiratory muscle mechanical work of breathing. Thus, IL-6 may play an active role in the pathogenesis of respiratory system diseases. The possible involved mechanisms are discussed.

  12. Left ventricular dysfunction induced by cold exposure in patients with systemic sclerosis

    SciTech Connect

    Ellis, W.W.; Baer, A.N.; Robertson, R.M.; Pincus, T.; Kronenberg, M.W.

    1986-03-01

    Raynaud's phenomenon and cardiac abnormalities are frequent in patients with systemic sclerosis. Radionuclide ventriculograms were obtained in 16 patients with Raynaud's phenomenon and systemic sclerosis or the related CREST syndrome and in 11 normal volunteers in order to evaluate changes in left ventricular function that might be induced by exposure to cold. Left ventricular regional wall motion abnormalities developed in nine of 16 patients during cooling compared with only one of 11 control subjects, despite a comparable rise in mean arterial pressure (p less than 0.02). The abnormalities occurred in seven of 11 patients with systemic sclerosis, one of four with CREST syndrome, and one with Raynaud's disease. To test the potential protective effect of nifedipine, radionuclide ventriculograms were then obtained during cooling after sublingual nifedipine (20 mg). Only five of 13 patients had wall motion abnormalities, and the severity of the abnormalities was significantly less than during the first cooling period (p = 0.03). Five of eight patients who had cold-induced wall motion abnormalities during the first cooling period had none after nifedipine, whereas two other patients demonstrated small abnormalities only during the second cooling period after treatment with nifedipine. It is concluded that cold induces segmental myocardial dysfunction in patients with systemic sclerosis and that nifedipine may blunt the severity of this abnormal response.

  13. Laser-induced damage threshold of camera sensors and micro-opto-electro-mechanical systems

    NASA Astrophysics Data System (ADS)

    Schwarz, Bastian; Ritt, Gunnar; Körber, Michael; Eberle, Bernd

    2016-10-01

    The continuous development of laser systems towards more compact and efficient devices constitutes an increasing threat to electro-optical imaging sensors such as complementary metal-oxide-semiconductors (CMOS) and charge-coupled devices (CCD). These types of electronic sensors are used in day-to-day life but also in military or civil security applications. In camera systems dedicated to specific tasks, also micro-opto-electro-mechanical systems (MOEMS) like a digital micromirror device (DMD) are part of the optical setup. In such systems, the DMD can be located at an intermediate focal plane of the optics and it is also susceptible to laser damage. The goal of our work is to enhance the knowledge of damaging effects on such devices exposed to laser light. The experimental setup for the investigation of laser-induced damage is described in detail. As laser sources both pulsed lasers and continuous-wave (CW) lasers are used. The laser-induced damage threshold (LIDT) is determined by the single-shot method by increasing the pulse energy from pulse to pulse or in the case of CW-lasers, by increasing the laser power. Furthermore, we investigate the morphology of laser-induced damage patterns and the dependence of the number of destructed device elements on the laser pulse energy or laser power. In addition to the destruction of single pixels, we observe aftereffects like persisting dead columns or rows of pixels in the sensor image.

  14. Current-induced forces in mesoscopic systems: A scattering-matrix approach.

    PubMed

    Bode, Niels; Kusminskiy, Silvia Viola; Egger, Reinhold; von Oppen, Felix

    2012-01-01

    Nanoelectromechanical systems are characterized by an intimate connection between electronic and mechanical degrees of freedom. Due to the nanoscopic scale, current flowing through the system noticeably impacts upons the vibrational dynamics of the device, complementing the effect of the vibrational modes on the electronic dynamics. We employ the scattering-matrix approach to quantum transport in order to develop a unified theory of nanoelectromechanical systems out of equilibrium. For a slow mechanical mode the current can be obtained from the Landauer-Büttiker formula in the strictly adiabatic limit. The leading correction to the adiabatic limit reduces to Brouwer's formula for the current of a quantum pump in the absence of a bias voltage. The principal results of the present paper are the scattering-matrix expressions for the current-induced forces acting on the mechanical degrees of freedom. These forces control the Langevin dynamics of the mechanical modes. Specifically, we derive expressions for the (typically nonconservative) mean force, for the (possibly negative) damping force, an effective "Lorentz" force that exists even for time-reversal-invariant systems, and the fluctuating Langevin force originating from Nyquist and shot noise of the current flow. We apply our general formalism to several simple models that illustrate the peculiar nature of the current-induced forces. Specifically, we find that in out-of-equilibrium situations the current-induced forces can destabilize the mechanical vibrations and cause limit-cycle dynamics.

  15. Measurement and Analysis of CN Violet System in Laser-Induced Plasma

    NASA Astrophysics Data System (ADS)

    Behery, Sultan A.; Parigger, Christian G.

    2014-03-01

    Pulsed, infrared Nd:YAG laser radiation is utilized to ablate material from carbon-containing samples in air. Time-resolved measurements of the micro-plasma show well-developed diatomic spectra of the CN violet system. Of Interest are interferences from the C2 Deslandres D'Azambuja system in the CN spectra, as previously noted in experiments with CO2 laser radiation focused into CO2 gas expanding into air. The recombination emission spectra from diatomic species, e.g., CN or C2, clearly indicate temperatures in excess of 6000 Kelvin. Studies of the CO2 TEA laser-induced micro-plasmas show these highly excited, high-temperature molecular transitions several tens of microseconds after plasma generation, mixed with signatures of Stark-broadened atomic lines. Spectroscopic fitting with accurate molecular line strengths of superposed emission spectra is of current interest, including study of the C2 Deslandres D'Azambuja system near the 4-4 band of the CN Δv = 0 sequence of the CN B2Σ+ --> X2Σ+ Violet System. In addition, discussed are physics phenomena associated with laser-induced optical breakdown. Laser-induced plasma applications include characterization of carbon and nitrogen containing materials.

  16. Systemic resistance to gray mold induced in tomato by benzothiadiazole and Trichoderma harzianum T39.

    PubMed

    Harel, Yael Meller; Mehari, Zeraye Haile; Rav-David, Dalia; Elad, Yigal

    2014-02-01

    Gray mold (Botrytis cinerea) is an important disease of tomato (Solanum lycopersicum). This study examined defense-related gene expression involved in the resistance to B. cinerea that is induced in tomato plants by benzothiadiazole and Trichoderma harzianum T39 soil drench. In whole plants, transcriptional changes related to salicylic acid and ethylene were induced by the application of a 0.01% benzothiadiazole solution, whereas changes related to jasmonic acid were induced by the application of a 0.4% T39 suspension. On detached leaves, soil treatment by T39 led to enhanced resistance to B. cinerea infection that was proportional to the concentration of the T39 suspension. By 5 days after pathogen inoculation, the plants that had received the 0.04% T39 drench exhibited 62% less severe disease than the untreated plants. The 0.4% T39 drench led to an 84% reduction in disease severity. Observations of B. cinerea infection in leaves harvested from plants grown in the treated soils revealed that drenching with a T39 suspension induces systemic resistance against B. cinerea and primes salicylic acid- and ethylene-related gene expression in a manner proportional to the concentration of the biocontrol agent. Benzothiadiazole treatment induced resistance to gray mold independently of salicylic acid and led to strong priming of two genes known to be involved in defense against B. cinerea, Pti5 and PI2.

  17. Pumping-induced drawdown and stream depletion in a leaky aquifer system

    USGS Publications Warehouse

    Butler, J.J.; Zhan, X.; Zlotnik, V.A.

    2007-01-01

    The impact of ground water pumping on nearby streams is often estimated using analytic models of the interconnected stream-aquifer system. A common assumption of these models is that the pumped aquifer is underlain by an impermeable formation. A new semianalytic solution for drawdown and stream depletion has been developed that does not require this assumption. This solution shows that pumping-induced flow (leakage) through an underlying aquitard can be an important recharge mechanism in many stream-aquifer systems. The relative importance of this source of recharge increases with the distance between the pumping well and the stream. The distance at which leakage becomes the primary component of the pumping-induced recharge depends on the specific properties of the aquifer, aquitard, and streambed. Even when the aquitard is orders of magnitude less transmissive than the aquifer, leakage can be an important recharge mechanism because of the large surface area over which it occurs. Failure to consider aquitard leakage can lead to large overestimations of both the drawdown produced by pumping and the contribution of stream depletion to the pumping-induced recharge. The ramifications for water resources management and water rights adjudication can be significant. A hypothetical example helps illustrate these points and demonstrates that more attention should be given to estimating the properties of aquitards underlying stream-aquifer systems. The solution presented here should serve as a relatively simple but versatile tool for practical assessments of pumping-induced stream-aquifer interactions. However, this solution should not be used for such assessments without site-specific data that indicate pumping has induced leakage through the aquitard. ?? 2006 National Ground Water Association.

  18. Adipose-Derived Mesenchymal Stem Cells Prevent Systemic Bone Loss in Collagen-Induced Arthritis

    PubMed Central

    Garimella, Manasa G.; Kour, Supinder; Piprode, Vikrant; Mittal, Monika; Kumar, Anil; Rani, Lekha; Pote, Satish T.; Mishra, Gyan C.; Chattopadhyay, Naibedya

    2015-01-01

    Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammatory synovitis leading to joint destruction and systemic bone loss. The inflammation-induced bone loss is mediated by increased osteoclast formation and function. Current antirheumatic therapies primarily target suppression of inflammatory cascade with limited or no success in controlling progression of bone destruction. Mesenchymal stem cells (MSCs) by virtue of their tissue repair and immunomodulatory properties have shown promising results in various autoimmune and degenerative diseases. However, the role of MSCs in prevention of bone destruction in RA is not yet understood. In this study, we investigated the effect of adipose-derived MSCs (ASCs) on in vitro formation of bone-resorbing osteoclasts and pathological bone loss in the mouse collagen-induced arthritis (CIA) model of RA. We observed that ASCs significantly inhibited receptor activator of NF-κB ligand (RANKL)–induced osteoclastogenesis in both a contact-dependent and -independent manner. Additionally, ASCs inhibited RANKL-induced osteoclastogenesis in the presence of proinflammatory cytokines such as TNF-α, IL-17, and IL-1β. Furthermore, treatment with ASCs at the onset of CIA significantly reduced clinical symptoms and joint pathology. Interestingly, ASCs protected periarticular and systemic bone loss in CIA mice by maintaining trabecular bone structure. We further observed that treatment with ASCs reduced osteoclast precursors in bone marrow, resulting in decreased osteoclastogenesis. Moreover, ASCs suppressed autoimmune T cell responses and increased the percentages of peripheral regulatory T and B cells. Thus, we provide strong evidence that ASCs ameliorate inflammation-induced systemic bone loss in CIA mice by reducing osteoclast precursors and promoting immune tolerance. PMID:26538398

  19. Neuromodulatory effects of the dorsal hippocampal endocannabinoid system in dextromethorphan/morphine-induced amnesia.

    PubMed

    Ghasemzadeh, Zahra; Rezayof, Ameneh

    2017-01-05

    Dextromethorphan which is an active ingredient in many cough medicines has been previously shown to potentiate amnesic effect of morphine in rats. However, the effect of dextromethorphan, that is also a noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist, in combination with morphine on hippocampus-based long term memory has not been well characterized. The aim of the present study was to assess the possible role of endocannabinoid system of the dorsal hippocampus in dextromethorphan /morphine-induced amnesia. Our results showed that intraperitoneal (i.p.) injection of morphine (5mg/kg) or dextromethorphan (5-15mg/kg) before testing the passive avoidance learning induced amnesia. Combination of ineffective doses of dextromethorphan (7.5mg/kg, i.p.) and morphine (2mg/kg, i.p.) also produced amnesia, suggesting the enhancing effects of the drugs. To assess the effect of the activation or inhibition of the dorsal hippocampal cannabinoid CB1 receptors on this amnesia, ACPA or AM251 as selective receptor agonists or antagonists were respectively injected into the CA1 regions before systemic injection of dextromethorphan and morphine. Interestingly, intra-CA1 microinjection of ACPA (0.5-1ng/rat) improved the amnesic effect of dextromethorphan /morphine combination. The microinjection of AM251 into the CA1 region enhanced the response of the combination of dextromethorphan /morphine in inducing amnesia. Moreover, Intra-CA1 microinjection of AM251 inhibited the improving effect of ACPA on dextromethorphan /morphine-induced amnesia. It is important to note that intra-CA1 microinjection of the same doses of the agonist or antagonist by itself had no effects on memory formation. Thus, it can be concluded that the dorsal hippocampal endocannabinoid system, via CB1 receptor-dependent mechanism, may be involved in morphine/dextromethorphan -induced amnesia.

  20. Familial hypercholesterolemia impairs exercise-induced systemic vasodilation due to reduced NO bioavailability.

    PubMed

    de Beer, Vincent J; Merkus, Daphne; Bender, Shawn B; Tharp, Darla L; Bowles, Douglas K; Duncker, Dirk J; Laughlin, M Harold

    2013-12-01

    Hypercholesterolemia impairs endothelial function [e.g., the nitric oxide (NO)-cyclic GMP-phosphodiesterase 5 (PDE5) pathway], limits shear stress-induced vasodilation, and is therefore expected to reduce exercise-induced vasodilation. To assess the actual effects of hypercholesterolemia on endothelial function and exercise-induced vasodilation, we compared the effects of endothelial NO synthase (eNOS) and PDE5 inhibition in chronically instrumented Yucatan (Control) and Rapacz familial hypercholesterolemic (FH) swine, at rest and during treadmill exercise. The increases in systemic vascular conductance produced by ATP (relative to nitroprusside) and exercise were blunted in FH compared with Control swine. The vasoconstrictor response to eNOS inhibition, with nitro-l-arginine (NLA), was attenuated in FH compared with Control swine, both at rest and during exercise. Furthermore, whereas the vasodilator response to nitroprusside was enhanced slightly, the vasodilator response to PDE5 inhibition, with EMD360527, was reduced in FH compared with Control swine. Finally, in the pulmonary circulation, FH resulted in attenuated vasodilator responses to ATP, while maintaining the responses to both NLA and EMD360527. In conclusion, hypercholesterolemia reduces exercise-induced vasodilation in the systemic but not the pulmonary circulation. This reduction appears to be the principal result of a decrease in NO bioavailability, which is mitigated by a lower PDE5 activity.

  1. Urtica dioica leaves modulates muscarinic cholinergic system in the hippocampus of streptozotocin-induced diabetic mice.

    PubMed

    Patel, Sita Sharan; Parashar, Arun; Udayabanu, Malairaman

    2015-06-01

    Diabetes mellitus is a chronic metabolic disorder and has been associated with cognitive dysfunction. In our earlier study, chronic Urtica dioica (UD) treatment significantly ameliorated diabetes induced associative and spatial memory deficit in mice. The present study was designed to explore the effect of UD leaves extract on muscarinic cholinergic system, which has long been known to be involved in cognition. Streptozotocin (STZ) (50 mg/kg, i.p., consecutively for 5 days) was used to induce diabetes followed by treatment with UD extract (50 mg/kg, oral) or rosiglitazone (5 mg/kg, oral) for 8 weeks. STZ-induced diabetic mice showed significant reduction in hippocampal muscarinic acetylcholine receptor-1 and choline acetyltransferase expressions. Chronic diabetes significantly up-regulated the protein expression of acetylcholinesterase associated with oxidative stress in hippocampus. Besides, STZ-induced diabetic mice showed hypolocomotion with up-regulation of muscarinic acetylcholine receptor-4 expression in striatum. Chronic UD treatment significantly attenuated the cholinergic dysfunction and oxidative stress in the hippocampus of diabetic mice. UD had no effect on locomotor activity and muscarinic acetylcholine receptor-4 expression in striatum. In conclusion, UD leaves extract has potential to reverse diabetes mediated alteration in muscarinic cholinergic system in hippocampus and thereby improve memory functions.

  2. Acute Resistance Exercise Induces Antinociception by Activation of the Endocannabinoid System in Rats

    PubMed Central

    Galdino, Giovane; Romero, Thiago; da Silva, José Felippe Pinho; Aguiar, Daniele; de Paula, Ana Maria; Cruz, Jader; Parrella, Cosimo; Piscitelli, Fabiana; Duarte, Igor; Di Marzo, Vincenzo; Perez, Andrea

    2014-01-01

    Background Resistance exercise (RE) is also known as strength training, and it is performed to increase the strength and mass of muscles, bone strength and metabolism. RE has been increasingly prescribed for pain relief. However, the endogenous mechanisms underlying this antinociceptive effect are still largely unexplored. Thus, we investigated the involvement of the endocannabinoid system in RE-induced antinociception. Methods Male Wistar rats were submitted to acute RE in a weight-lifting model. The nociceptive threshold was measured by a mechanical nociceptive test (paw pressure) before and after exercise. To investigate the involvement of cannabinoid receptors and endocannabinoids in RE-induced antinociception, cannabinoid receptor inverse agonists, endocannabinoid metabolizing enzyme inhibitors and an anandamide reuptake inhibitor were injected before RE. After RE, CB1 cannabinoid receptors were quantified in rat brain tissue by Western blot and immunofluorescence. In addition, endocannabinoid plasma levels were measured by isotope dilution-liquid chromatography mass spectrometry. Results RE-induced antinociception was prevented by preinjection with CB1 and CB2 cannabinoid receptor inverse agonists. By contrast, preadministration of metabolizing enzyme inhibitors and the anandamide reuptake inhibitor prolonged and enhanced this effect. RE also produced an increase in the expression and activation of CB1 cannabinoid receptors in rat brain tissue and in the dorsolateral and ventrolateral periaqueductal regions and an increase of endocannabinoid plasma levels. Conclusion The present study suggests that a single session of RE activates the endocannabinoid system to induce antinociception. PMID:24977916

  3. Renal Denervation Improves the Baroreflex and GABA System in Chronic Kidney Disease-induced Hypertension

    PubMed Central

    Chen, Hsin-Hung; Cheng, Pei-Wen; Ho, Wen-Yu; Lu, Pei-Jung; Lai, Chi-Cheng; Tseng, Yang-Ming; Fang, Hua-Chang; Sun, Gwo-Ching; Hsiao, Michael; Liu, Chun-Peng; Tseng, Ching-Jiunn

    2016-01-01

    Hypertensive rats with chronic kidney disease (CKD) exhibit enhanced gamma-aminobutyric acid (GABA)B receptor function and regulation within the nucleus tractus solitarii (NTS). For CKD with hypertension, renal denervation (RD) interrupts the afferent renal sympathetic nerves, which are connecting to the NTS. The objective of the present study was to investigate how RD improves CKD-induced hypertension. Rats underwent 5/6 nephrectomy for 8 weeks, which induced CKD and hypertension. RD was induced by applying phenol to surround the renal artery in CKD. RD improved blood pressure (BP) by lowering sympathetic nerve activity and markedly restored the baroreflex response in CKD. The GABAB receptor expression was increased in the NTS of CKD; moreover, the central GABA levels were reduced in the cerebrospinal fluid, and the peripheral GABA levels were increased in the serum. RD restored the glutamic acid decarboxylase activity in the NTS in CKD, similar to the effect observed for central treatment with baclofen, and the systemic administration of gabapentin reduced BP. RD slightly improved renal function and cardiac load in CKD. RD may improve CKD-induced hypertension by modulating the baroreflex response, improving GABA system dysfunction and preventing the development and reducing the severity of cardiorenal syndrome type 4 in CKD rats. PMID:27917928

  4. Individual differences in the locus coeruleus-norepinephrine system: Relevance to stress-induced cardiovascular vulnerability.

    PubMed

    Wood, Christopher S; Valentino, Rita J; Wood, Susan K

    2017-04-01

    Repeated exposure to psychosocial stress is a robust sympathomimetic stressor and as such has adverse effects on cardiovascular health. While the neurocircuitry involved remains unclear, the physiological and anatomical characteristics of the locus coeruleus (LC)-norepinephrine (NE) system suggest that it is poised to contribute to stress-induced cardiovascular vulnerability. A major theme throughout is to review studies that shed light on the role that the LC may play in individual differences in vulnerability to social stress-induced cardiovascular dysfunction. Recent findings are discussed that support a unique plasticity in afferent regulation of the LC, resulting in either excitatory or inhibitory input to the LC during establishment of different stress coping strategies. This contrasting regulation of the LC by either afferent regulation, or distinct differences in stress-induced neuroinflammation would translate to differences in cardiovascular regulation and may serve as the basis for individual differences in the cardiopathological consequences of social stress. The goal of this review is to highlight recent developments in the interplay between the LC-NE and cardiovascular systems during repeated stress in an effort to advance therapeutic treatments for the development of stress-induced cardiovascular vulnerability.

  5. Sensory-induced plasticity of motor pattern selection in the lobster stomatogastric nervous system.

    PubMed

    Nargeot, R; Moulins, M

    1997-08-01

    In a previous study, a bilateral sensory input pathway to the crustacean stomatogastric nervous system was reported to induce the functional switching of an identified motor neuron (VD) from one rhythm generating neural network (the pyloric circuit) to another (the cardiac sac network). In the present in vitro study on the spiny lobster, Palinurus vulgaris, we have shown that under certain conditions, repetitive trains of phasic stimulation (1 s, 40 Hz) of one of these sensory nerves elicits either an increase or a decrease in efficacy of the VD switching response. In preparations showing no previous sign either of increase or decrease in VD switching, either response can be induced by prior conditioning stimulation. The increasing effect can be induced by unpaired conditioning stimulation of the contralateral sensory nerve. Conversely, the decrease in switching efficacy is obtained by pairing stimulation of the sensory-motor pathway with that applied to its contralateral partner. Both the experimentally induced increase and decrease in VD switching are long-lasting, remaining observable for at least 20 min and in some cases up to 3 h after the original conditioning procedure. Our results suggest that this system provides a suitable 'simple' model for the analysis of experience-related plasticity of the switching of a neuron from one network to another.

  6. Evidence for GABA-Induced Systemic GABA Accumulation in Arabidopsis upon Wounding

    PubMed Central

    Scholz, Sandra S.; Malabarba, Jaiana; Reichelt, Michael; Heyer, Monika; Ludewig, Frank; Mithöfer, Axel

    2017-01-01

    The non-proteinogenic amino acid γ-aminobutyric acid (GABA) is present in all plant species analyzed so far. Its synthesis is stimulated by either acidic conditions occurring after tissue disruption or higher cytosolic calcium level. In mammals, GABA acts as inhibitory neurotransmitter but its function in plants is still not well understood. Besides its involvement in abiotic stress resistance, GABA has a role in the jasmonate-independent defense against invertebrate pests. While the biochemical basis for GABA accumulation in wounded leaves is obvious, the underlying mechanisms for wounding-induced GABA accumulation in systemic leaves remained unclear. Here, the Arabidopsis thaliana knock-out mutant lines pop2-5, unable to degrade GABA, and tpc1-2, lacking a wounding-induced systemic cytosolic calcium elevation, were employed for a comprehensive investigation of systemic GABA accumulation. A wounding-induced systemic GABA accumulation was detected in tpc1-2 plants demonstrating that an increased calcium level was not involved. Similarly, after both mechanical wounding and Spodoptera littoralis feeding, GABA accumulation in pop2-5 plants was significantly higher in local and systemic leaves, compared to wild-type plants. Consequently, larvae feeding on these GABA-enriched mutant plants grew significantly less. Upon exogenous application of a D2-labeled GABA to wounded leaves of pop2-5 plants, its uptake but no translocation to unwounded leaves was detected. In contrast, an accumulation of endogenous GABA was observed in vascular connected systemic leaves. These results suggest that the systemic accumulation of GABA upon wounding does not depend on the translocation of GABA or on an increase in cytosolic calcium. PMID:28382046

  7. Neuroinflammation and oxidative stress in rostral ventrolateral medulla contribute to neurogenic hypertension induced by systemic inflammation

    PubMed Central

    2012-01-01

    Background In addition to systemic inflammation, neuroinflammation in the brain, which enhances sympathetic drive, plays a significant role in cardiovascular diseases, including hypertension. Oxidative stress in rostral ventrolateral medulla (RVLM) that augments sympathetic outflow to blood vessels is involved in neural mechanism of hypertension. We investigated whether neuroinflammation and oxidative stress in RVLM contribute to hypertension following chronic systemic inflammation. Methods In normotensive Sprague-Dawley rats, systemic inflammation was induced by infusion of Escherichia coli lipopolysaccharide (LPS) into the peritoneal cavity via an osmotic minipump. Systemic arterial pressure and heart rate were measured under conscious conditions by the non-invasive tail-cuff method. The level of the inflammatory markers in plasma or RVLM was analyzed by ELISA. Protein expression was evaluated by Western blot or immunohistochemistry. Tissue level of superoxide anion (O2·-) in RVLM was determined using the oxidation-sensitive fluorescent probe dihydroethidium. Pharmacological agents were delivered either via infusion into the cisterna magna with an osmotic minipump or microinjection bilaterally into RVLM. Results Intraperitoneal infusion of LPS (1.2 mg/kg/day) for 14 days promoted sustained hypertension and induced a significant increase in plasma level of C-reactive protein, tumor necrosis factor-α (TNF-α), or interleukin-1β (IL-1β). This LPS-induced systemic inflammation was accompanied by activation of microglia, augmentation of IL-1β, IL-6, or TNF-α protein expression, and O2·- production in RVLM, all of which were blunted by intracisternal infusion of a cycloxygenase-2 (COX-2) inhibitor, NS398; an inhibitor of microglial activation, minocycline; or a cytokine synthesis inhibitor, pentoxifylline. Neuroinflammation in RVLM was also associated with a COX-2-dependent downregulation of endothelial nitric oxide synthase and an upregulation of

  8. Identification and counteraction of microbe-induced corrosion in metallic systems

    SciTech Connect

    Stein, A.A.

    1986-11-01

    Biological attack of metallic systems is a longstanding problem that affects all structural materials in a variety of environment and systems. Corrosion of buried pipelines by sulfate-reducing bacteria has been studied by the petrochemical industry for years. In the power industry, corrosion studies have focused on condensers and service water systems where slime, barnacles, clams, and other macro-organisms are easily detected. Efforts have been made to eliminate the effect of these organisms through the use of chlorination, back-flushing, organic coatings, or thermal shock. The objective was to maintain component performance by eliminating biofouling and reducing metallic corrosion. Recently, it has been recognized that corrosion caused by micro-organisms can occur even in very clean systems. This article gives guidelines for the identification and counteraction of microbe-induced corrosion in metallic systems.

  9. Task-Induced Symmetry and Reduction in Kinematic Systems with Application to Needle Steering.

    PubMed

    Kallem, Vinutha; Chang, Dong Eui; Cowan, Noah J

    2007-10-29

    Lie group symmetry in a mechanical system can lead to a dimensional reduction in its dynamical equations. Typically, the symmetries that one exploits are intrinsic to the mechanical system at hand, e.g. invariance of the system's Lagrangian to some group of motions. In the present work we consider symmetries that arise from an extrinsic control task, rather than the intrinsic structure of configuration space, constraints, or system dynamics. We illustrate this technique with several examples. In the examples, the reduction enables us to design essentially global feedback controllers on the reduced systems.We apply task-induced symmetry and reduction to a recently developed 6 DOF kinematic model of steerable bevel-tip needles. The resulting controllers cause the needle tip to track a subspace of its configuration space. We envision that the methodology presented in this paper will form the basis for a new planning and control framework for needle steering.

  10. DESIGN OF MIRRORS AND APODIZATION FUNCTIONS IN PHASE-INDUCED AMPLITUDE APODIZATION SYSTEMS

    SciTech Connect

    Cady, Eric

    2012-08-01

    Phase-induced amplitude apodization (PIAA) coronagraphs are a promising technology for imaging exoplanets, with the potential to detect Earth-like planets around Sun-like stars. A PIAA system nominally consists of a pair of mirrors that reshape incident light without attenuation, coupled with one or more apodizers to mitigate diffraction effects or provide additional beam shaping to produce a desired output profile. We present a set of equations that allow apodizers to be chosen for any given pair of mirrors, or conversely mirror shapes chosen for given apodizers, to produce an arbitrary amplitude profile at the output of the system. We show how classical PIAA systems may be designed by this method and present the design of a novel four-mirror system with higher throughput than a standard two-mirror system. We also discuss the limitations due to diffraction and the design steps that may be taken to mitigate them.

  11. Systems and methods for locating and imaging proppant in an induced fracture

    SciTech Connect

    Aldridge, David F.; Bartel, Lewis C.

    2016-02-02

    Born Scattering Inversion (BSI) systems and methods are disclosed. A BSI system may be incorporated in a well system for accessing natural gas, oil and geothermal reserves in a geologic formation beneath the surface of the Earth. The BSI system may be used to generate a three-dimensional image of a proppant-filled hydraulically-induced fracture in the geologic formation. The BSI system may include computing equipment and sensors for measuring electromagnetic fields in the vicinity of the fracture before and after the fracture is generated, adjusting the parameters of a first Born approximation model of a scattered component of the surface electromagnetic fields using the measured electromagnetic fields, and generating the image of the proppant-filled fracture using the adjusted parameters.

  12. Delayed effort-induced swelling with myofasciitis and systemic manifestations: A so far unrecognized type of pressure-induced urticaria

    PubMed Central

    Bursztejn, Anne-Claire; Lipsker, Dan

    2017-01-01

    Abstract Diseases characterized by recurrent symptoms with prolonged intervals without any clinical manifestations can pose diagnostic difficulties. Some diagnoses will be obvious but other situations can be very challenging. To nosologically delineate a new entity characterized by recurrent flares of induration of the forearms and legs with swelling of the extremities accompanied by intense fatigue and variable other symptoms. Retrospective observational study of patients recorded from 2000 to 2015. All patients included were seen during a consultation at the Dermatology Department of the University Hospital of Strasbourg, France. We retrieved the medical records from patients seen and recorded over the last 16 years having induration of the extremities, the forearm and the legs occurring between 4 and 12 hours after a physical effort accompanied by systemic signs that lasted for a few days. We analyzed in detail the clinical and biological features, evolution, and treatments of these patients. We included 6 males, with a mean age of 47 years; mean age at disease onset was 42. All patients were initially misdiagnosed as having rheumatic disorders. The mean delay before diagnosis was 5 years. The main complaint was painful induration or muscle soreness of the forearms and the legs associated with transient functional impairment and prolonged asthenia for a mean duration of 3.5 days. Induration of the deep soft tissues was very suggestive of myofasciitis. The delay between the triggering physical effort and the swelling was between 6 and 12 hours. Physical effort as triggering factor was never spontaneously mentioned. Two patients had partial response to high dose antihistamines and 2 other patients to the interleukin-1 inhibitor anakinra. One patient responded to hydroxychloroquine. The very stereotypical presentation in those 6 patients suggests that this is a recognizable entity characterized by effort-induced induration of forearms and/or legs, due to deep

  13. The oxidative stress-inducible cystine/glutamate antiporter, system x (c) (-) : cystine supplier and beyond.

    PubMed

    Conrad, Marcus; Sato, Hideyo

    2012-01-01

    The oxidative stress-inducible cystine/glutamate exchange system, system x (c) (-) , transports one molecule of cystine, the oxidized form of cysteine, into cells and thereby releases one molecule of glutamate into the extracellular space. It consists of two protein components, the 4F2 heavy chain, necessary for membrane location of the heterodimer, and the xCT protein, responsible for transport activity. Previously, system x (c) (-) has been regarded to be a mere supplier of cysteine to cells for the synthesis of proteins and the antioxidant glutathione (GSH). In that sense, oxygen, electrophilic agents, and bacterial lipopolysaccharide trigger xCT expression to accommodate with increased oxidative stress by stimulating GSH biosynthesis. However, emerging evidence established that system x (c) (-) may act on its own as a GSH-independent redox system by sustaining a redox cycle over the plasma membrane. Hallmarks of this cycle are cystine uptake, intracellular reduction to cysteine and secretion of the surplus of cysteine into the extracellular space. Consequently, increased levels of extracellular cysteine provide a reducing microenvironment required for proper cell signaling and communication, e.g. as already shown for the mechanism of T cell activation. By contrast, the enhanced release of glutamate in exchange with cystine may trigger neurodegeneration due to glutamate-induced cytotoxic processes. This review aims to provide a comprehensive picture from the early days of system x (c) (-) research up to now.

  14. Optical Analog to Electromagnetically Induced Transparency in Cascaded Ring-Resonator Systems

    PubMed Central

    Wang, Yonghua; Zheng, Hua; Xue, Chenyang; Zhang, Wendong

    2016-01-01

    The analogue of electromagnetically induced transparency in optical methods has shown great potential in slow light and sensing applications. Here, we experimentally demonstrated a coupled resonator induced transparency system with three cascaded ring coupled resonators in a silicon chip. The structure was modeled by using the transfer matrix method. Influences of various parameters including coupling ratio of couplers, waveguide loss and additional loss of couplers on transmission characteristic and group index have been investigated theoretically and numerically in detail. The transmission character of the system was measured by the vertical grating coupling method. The enhanced quality factor reached 1.22 × 105. In addition, we further test the temperature performance of the device. The results provide a new method for the manipulation of light in highly integrated optical circuits and sensing applications. PMID:27463720

  15. Quantum dynamics of a two-state system induced by a chirped zero-area pulse

    NASA Astrophysics Data System (ADS)

    Lee, Han-gyeol; Song, Yunheung; Kim, Hyosub; Jo, Hanlae; Ahn, Jaewook

    2016-02-01

    It is well known that area pulses make Rabi oscillation and chirped pulses in the adiabatic interaction regime induce complete population inversion of a two-state system. Here we show that chirped zero-area pulses could engineer an interplay between the adiabatic evolution and Rabi-like rotations. In a proof-of-principle experiment utilizing spectral chirping of femtosecond laser pulses with a resonant spectral hole, we demonstrate that the chirped zero-area pulses could induce, for example, complete population inversion and return of the cold rubidium atom two-state system. Experimental result agrees well with the theoretically considered overall dynamics, which could be approximately modeled to a Ramsey-like three-pulse interaction, where the x and z rotations are driven by the hole and the main pulse, respectively.

  16. Inducible protein expression in Drosophila Schneider 2 cells using the lac operator-repressor system.

    PubMed

    Wakiyama, Motoaki; Muramatsu, Reiko; Kaitsu, Yoko; Ikeda, Mariko; Yokoyama, Shigeyuki

    2011-12-01

    Schneider line 2 cells, derived from Drosophila melanogaster, can be used as a highly versatile gene expression system. Two powerful promoters derived from the actin5C (Ac5) and metallothionein (Mtn) genes are available. The Mtn promoter can be used for the inducible expression of heterologous proteins unsuitable for constitutive expression. However, to circumvent using CuSO(4) or CdCl(2) as inducers of the Mtn promoter, we created a modified Ac5 promoter, Ac5LacO, in which two short lac operator sequences are embedded. Expression from the Ac5LacO promoter was regulated with co-expression of the lac repressor and IPTG. More than 25-fold induction of firefly luciferase expression was achieved in transient transfection experiments. Furthermore, we demonstrated that the lac operator-repressor regulatory system functioned in chromosomally integrated cell lines.

  17. Alterations in the hippocampal endocannabinoid system in diet-induced obese mice.

    PubMed

    Massa, Federico; Mancini, Giacomo; Schmidt, Helmut; Steindel, Frauke; Mackie, Ken; Angioni, Carlo; Oliet, Stéphane H R; Geisslinger, Gerd; Lutz, Beat

    2010-05-05

    The endocannabinoid (eCB) system plays central roles in the regulation of food intake and energy expenditure. Its alteration in activity contributes to the development and maintenance of obesity. Stimulation of the cannabinoid receptor type 1 (CB(1) receptor) increases feeding, enhances reward aspects of eating, and promotes lipogenesis, whereas its blockade decreases appetite, sustains weight loss, increases insulin sensitivity, and alleviates dysregulation of lipid metabolism. The hypothesis has been put forward that the eCB system is overactive in obesity. Hippocampal circuits are not directly involved in the neuronal control of food intake and appetite, but they play important roles in hedonic aspects of eating. We investigated the possibility whether or not diet-induced obesity (DIO) alters the functioning of the hippocampal eCB system. We found that levels of the two eCBs, 2-arachidonoyl glycerol (2-AG) and anandamide, were increased in the hippocampus from DIO mice, with a concomitant increase of the 2-AG synthesizing enzyme diacylglycerol lipase-alpha and increased CB(1) receptor immunoreactivity in CA1 and CA3 regions, whereas CB(1) receptor agonist-induced [(35)S]GTPgammaS binding was unchanged. eCB-mediated synaptic plasticity was changed in the CA1 region, as depolarization-induced suppression of inhibition and long-term depression of inhibitory synapses were enhanced. Functionality of CB(1) receptors in GABAergic neurons was furthermore revealed, as mice specifically lacking CB(1) receptors on this neuronal population were partly resistant to DIO. Our results show that DIO-induced changes in the eCB system affect not only tissues directly involved in the metabolic regulation but also brain regions mediating hedonic aspects of eating and influencing cognitive processes.

  18. Ir doping-induced superconductivity in the SmFeAsO system.

    PubMed

    Chen, Yong Liang; Cheng, Cui Hua; Cui, Ya Jing; Zhang, Han; Zhang, Yong; Yang, Ye; Zhao, Yong

    2009-08-05

    The 5d transition metal Ir is successfully doped for Fe in SmFeAsO to induce superconductivity with T(c) = 16 K at a doping level of approximately 15 atom %. Ir doping decreases the As-Fe-As bond angle, beta; this behavior is different from the change in beta for the system with doping charges in the charge-reservoir layers.

  19. Analyzing electrostatic induced damage risk to reticles with an in situ e-reticle system

    NASA Astrophysics Data System (ADS)

    Tu, Richard; Sebald, Thomas

    2009-12-01

    E-Reticle system is an electrostatic field test device, which has the form factor of a conventional six inch quartz production reticle. The E-Reticle was used to assess the ESD damage risks in a mask cleaning tool. Test results indicate that a reticle may see higher than ITRS recommended electrostatic potential specifications when mechanical operations and cold DIW rinse start and in progress, hence seeing increased probability of electrostatic induced damages.

  20. Apparatus and Method for Elimination of Polarization-Induced Fading in Fiber-optic Sensor System

    NASA Technical Reports Server (NTRS)

    Chan, Hon Man (Inventor); Parker, Jr., Allen R. (Inventor)

    2015-01-01

    The invention is an apparatus and method of eliminating polarization-induced fading in interferometric fiber-optic sensor system having a wavelength-swept laser optical signal. The interferometric return signal from the sensor arms are combined and provided to a multi-optical path detector assembly and ultimately to a data acquisition and processing unit by way of a switch that is time synchronized with the laser scan sweep cycle.

  1. Coherent HF Radar System for the Study of Natural and Heater Induced Ionospheric Irregularities

    DTIC Science & Technology

    1993-06-01

    Services HF Active Auroral Research Program ( HAARP ) in Alaska. The DPS characterizes the bulk parameters of the ionosphere including changes of the...electron density, plasma structure and the plasma convection. In the absence of the HAARP facility at the present time, the high latitude ionosphere at...AD-A273 804 COHERENT HF RADAR SYSTEM FOR THE STUDY OF NATURAL AND HEATER INDUCED IONOSPHERIC IRREGULARITIES Bodo W. Reinisch James L. Scali D. Mark

  2. Noise-Induced Phase Locking and Frequency Mixing in an Optical Bistable System with Delayed Feedback

    NASA Astrophysics Data System (ADS)

    Misono, Masatoshi; Miyakawa, Kenji

    2011-11-01

    The interplay between stochastic resonance (SR) and coherence resonance (CR) is experimentally studied in an optical bistable system with a time-delayed feedback loop. We demonstrate that the phase of the noise-induced motion is locked to that of the periodic input when the ratio of their frequencies is a simple rational number. We also demonstrate that the interplay between SR and CR generates frequency-mixed modes, and that the efficiency of frequency mixing is enhanced by the optimum noise.

  3. A System Design Requirements Tool for Satellite Communications through Nuclear-Induced Scintillation

    DTIC Science & Technology

    1987-04-10

    DOCUMENT NUMBER BMO-TR-87-19 A SYSTEM DESIGN REQUIREM4ENTS TOOL FOR SATELLITE COMMNICATIONS THROUGH NUCLEAR-INDUCED SCINTILILATION *~MA Acoesslon For NT...parameters. Several contractors, most notably Mission Research Corporation , have contributed to the development of this model. The full DNA model was never...Performance," Briefing Mission Research Corporation , Santa Barbara, CA (no date). 26. Dana, "Antenna Impulse Response Functions, Theory and Applications

  4. Extracellular Vesicles Mediate Radiation-Induced Systemic Bystander Signals in the Bone Marrow and Spleen

    PubMed Central

    Szatmári, Tünde; Kis, Dávid; Bogdándi, Enikő Noémi; Benedek, Anett; Bright, Scott; Bowler, Deborah; Persa, Eszter; Kis, Enikő; Balogh, Andrea; Naszályi, Lívia N.; Kadhim, Munira; Sáfrány, Géza; Lumniczky, Katalin

    2017-01-01

    Radiation-induced bystander effects refer to the induction of biological changes in cells not directly hit by radiation implying that the number of cells affected by radiation is larger than the actual number of irradiated cells. Recent in vitro studies suggest the role of extracellular vesicles (EVs) in mediating radiation-induced bystander signals, but in vivo investigations are still lacking. Here, we report an in vivo study investigating the role of EVs in mediating radiation effects. C57BL/6 mice were total-body irradiated with X-rays (0.1, 0.25, 2 Gy), and 24 h later, EVs were isolated from the bone marrow (BM) and were intravenously injected into unirradiated (so-called bystander) animals. EV-induced systemic effects were compared to radiation effects in the directly irradiated animals. Similar to direct radiation, EVs from irradiated mice induced complex DNA damage in EV-recipient animals, manifested in an increased level of chromosomal aberrations and the activation of the DNA damage response. However, while DNA damage after direct irradiation increased with the dose, EV-induced effects peaked at lower doses. A significantly reduced hematopoietic stem cell pool in the BM as well as CD4+ and CD8+ lymphocyte pool in the spleen was detected in mice injected with EVs isolated from animals irradiated with 2 Gy. These EV-induced alterations were comparable to changes present in the directly irradiated mice. The pool of TLR4-expressing dendritic cells was different in the directly irradiated mice, where it increased after 2 Gy and in the EV-recipient animals, where it strongly decreased in a dose-independent manner. A panel of eight differentially expressed microRNAs (miRNA) was identified in the EVs originating from both low- and high-dose-irradiated mice, with a predicted involvement in pathways related to DNA damage repair, hematopoietic, and immune system regulation, suggesting a direct involvement of these pathways in mediating radiation-induced

  5. Rate-of-Change Dependence of the Performance of Two CGM Systems During Induced Glucose Swings

    PubMed Central

    Pleus, Stefan; Schoemaker, Michael; Morgenstern, Karin; Schmelzeisen-Redeker, Günther; Haug, Cornelia; Link, Manuela; Zschornack, Eva; Freckmann, Guido

    2015-01-01

    Introduction: The accuracy of continuous glucose monitoring (CGM) systems is often assessed with respect to blood glucose (BG) readings. CGM readings are affected by a physiological and a technical time delay when compared to BG readings. In this analysis, the dependence of CGM performance parameters on the BG rate of change was investigated for 2 CGM systems. Methods: Data from a previously published study were retrospectively analyzed. An established CGM system (Dexcom G4, Dexcom, San Diego, CA; system A) and a prototype system (Roche Diagnostics GmbH, Mannheim, Germany; system B) with 2 sensors each were worn by 10 subjects in parallel. Glucose swings were induced to achieve rapidly changing BG concentrations. Mean absolute relative differences (MARD) were calculated in different BG rate-of-change categories. In addition, sensor-to-sensor precision was assessed. Results: At BG rates of change of –1 mg/dl/min to 0 mg/dl/min and 0 mg/dl/min to +1 mg/dl/min, MARD results were 12.6% and 11.3% for system A and 8.2% and 10.0% for system B. At rapidly changing BG concentrations (<–3 mg/dl/min and ≥+3 mg/dl/min), higher MARD results were found for both systems, but system B was less affected (system A: 24.9% and 29.6%, system B: 10.6% and 16.3%). The impact of rate of change on sensor-to-sensor precision was less pronounced. Conclusions: Both systems were affected by rapidly changing BG concentrations to some degree, although system B was mostly unaffected by decreasing BG concentrations. It would seem that technological advancements in CGM systems might allow for a more precise tracking of BG concentrations even at rapidly changing BG concentrations. PMID:25852074

  6. System for measurement of small vibrations at material interfaces induced by electrostrictive forces

    SciTech Connect

    Ali, J.S.; Joines, W.T.

    1985-10-01

    The mechanisms of interaction of ELF and ELF-modulated RF fields with biological systems is presently an active area of research. Some models propose that field-induced forces may influence certain observed biological effects such as RF hearing and calcium ion efflux. To investigate the validity of the field-induced force model for the calcium-ion efflux effect, a system is needed which is capable of exposing samples to ELF fields or to ELF-modulated RF fields. At the same time the induced vibration caused by the forces of electrostriction must be monitored preferably by a noncontacting method. A microwave phase-sensitive receiver was designed to sense the small vibrations. Limitations on the receiver sensitivity imposed by phase noise is discussed. Phase noise measurement systems were designed and used to characterize the key receiver components. A limiting amplifier in the IF section of the receiver eliminates the need for knowledge of the reflection coefficient of the object of interest for quantitative vibration measurements.

  7. Control of absence seizures induced by the pathways connected to SRN in corticothalamic system.

    PubMed

    Hu, Bing; Guo, Daqing; Wang, Qingyun

    2015-06-01

    The cerebral cortex, thalamus and basal ganglia together form an important network in the brain, which is closely related to several nerve diseases, such as parkinson disease, epilepsy seizure and so on. Absence seizure can be characterized by 2-4 Hz oscillatory activity, and it can be induced by abnormal interactions between the cerebral cortex and thalamus. Many experimental results have also shown that basal ganglia are a key neural structure, which closely links the corticothalamic system in the brain. Presently, we use a corticothalamic-basal ganglia model to study which pathways in corticothalamic system can induce absence seizures and how these oscillatory activities can be controlled by projections from the substantia nigra pars reticulata (SNr) to the thalamic reticular nucleus (TRN) or the specific relay nuclei (SRN) of the thalamus. By tuning the projection strength of the pathway "Excitatory pyramidal cortex-SRN", "SRN-Excitatory pyramidal cortex" and "SRN-TRN" respectively, different firing states including absence seizures can appear. This indicates that absence seizures can be induced by tuning the connection strength of the considered pathway. In addition, typical absence epilepsy seizure state "spike-and-slow wave discharges" can be controlled by adjusting the activation level of the SNr as the pathways SNr-SRN and SNr-TRN open independently or together. Our results emphasize the importance of basal ganglia in controlling absence seizures in the corticothalamic system, and can provide a potential idea for the clinical treatment.

  8. Brucella spp. lumazine synthase: a novel adjuvant and antigen delivery system to effectively induce oral immunity.

    PubMed

    Rosas, Gabriela; Fragoso, Gladis; Ainciart, Natalia; Esquivel-Guadarrama, Fernando; Santana, Angélica; Bobes, Raúl J; Ramírez-Pliego, Oscar; Toledo, Andrea; Cruz-Revilla, Carmen; Meneses, Gabriela; Berguer, Paula; Goldbaum, Fernando A; Sciutto, Edda

    2006-04-01

    Brucella lumazine synthase (BLS) has been previously used with success as a delivery system for systemic immunization against murine cysticercosis. We herein determined the usefulness of BLS as a new antigen-delivery system and mucosal-adjuvant using KETc1, one of the peptides of the anti-cysticercosis vaccine. A protection of up to 98% was induced when KETc1 was used as a chimera fused to BLS. Used as adjuvant of KETc1, BLS also induced a high level of protection (79%), which did not significantly differ from that induced by the cholera toxin (74%). KETc1 and BLS administered separately also reduced the parasite load. KETc1 administered orally as a chimera, and to a lesser extent with BLS as adjuvant, elicited IgG and IgA specific antibodies, which were detectable both in fecal extracts and in sera, and increased B and CD4 activated cells. BLS-KETc1 also increased the levels of transcription of TNF-alpha, IL-2 and IFNgamma in Peyer's patches, and in spleen, only increased TNF-alpha was observed. Overall, these results showed that BLS can be used as both an antigen-carrier and as an adjuvant in the design of new oral subunit vaccines.

  9. Methamphetamine-induced changes in the mice hippocampal neuropeptide Y system: implications for memory impairment.

    PubMed

    Gonçalves, Joana; Baptista, Sofia; Olesen, Mikkel V; Fontes-Ribeiro, Carlos; Malva, João O; Woldbye, David P; Silva, Ana P

    2012-12-01

    Methamphetamine (METH) is a psychostimulant drug that causes irreversible brain damage leading to several neurological and psychiatric abnormalities, including cognitive deficits. Neuropeptide Y (NPY) is abundant in the mammalian central nervous system (CNS) and has several important functions, being involved in learning and memory processing. It has been demonstrated that METH induces significant alteration in mice striatal NPY, Y(1) and Y(2) receptor mRNA levels. However, the impact of this drug on the hippocampal NPY system and its consequences remain unknown. Thus, in this study, we investigated the effect of METH intoxication on mouse hippocampal NPY levels, NPY receptors function, and memory performance. Results show that METH increased NPY, Y(2) and Y(5) receptor mRNA levels, as well as total NPY binding accounted by opposite up- and down-regulation of Y(2) and Y(1) functional binding, respectively. Moreover, METH-induced impairment in memory performance and AKT/mammalian target of rapamycin pathway were both prevented by the Y(2) receptor antagonist, BIIE0246. These findings demonstrate that METH interferes with the hippocampal NPY system, which seems to be associated with memory failure. Overall, we concluded that Y(2) receptors are involved in memory deficits induced by METH intoxication.

  10. Mechanotransduction-Induced Lipid Production System with High Robustness and Controllability for Microalgae

    PubMed Central

    Cho, Myung Kwon; Shin, Hwa Sung

    2016-01-01

    Microalgae lipids are a promising energy source, but current biochemical methods of lipid-inductions such as nitrogen deprivation have low process robustness and controllability. Recently, use of mechanotransduction based membrane distortion by applying compression stress in a 2D-microsystem was suggested as a way to overcome these limitations of biochemical induction. However, reproduction in large numbers of cells without cell death has been difficult to overcome because compression for direct membrane distortion reduces culture volume and leads to cell death due to nutrient deprivation. In this study, a mechanotransduction-induced lipid production (MDLP) system that redirects elastic microbeads to induce membrane distortion of microalgae with alleviating cell death was developed. This system resulted in accumulation of lipid in as little as 4 hr. Once compressed, porous microbeads absorb media and swell simultaneously while homogeneously inducing compression stress of microalgae. The absorbed media within beads could be supplied to adjacent cells and could minimize cell death from nutrient deficiency. All mechanotransduction was confirmed by measuring upregulation of calcium influx and Mat3 genes. The microbeads ensured robustness and controllability in repeated compression/de-compression processes. Overall, the MDLP system has potential for use as a fundamental biodiesel process that requires robustness and controllability. PMID:27609701

  11. Mechanotransduction-Induced Lipid Production System with High Robustness and Controllability for Microalgae

    NASA Astrophysics Data System (ADS)

    Cho, Myung Kwon; Shin, Hwa Sung

    2016-09-01

    Microalgae lipids are a promising energy source, but current biochemical methods of lipid-inductions such as nitrogen deprivation have low process robustness and controllability. Recently, use of mechanotransduction based membrane distortion by applying compression stress in a 2D-microsystem was suggested as a way to overcome these limitations of biochemical induction. However, reproduction in large numbers of cells without cell death has been difficult to overcome because compression for direct membrane distortion reduces culture volume and leads to cell death due to nutrient deprivation. In this study, a mechanotransduction-induced lipid production (MDLP) system that redirects elastic microbeads to induce membrane distortion of microalgae with alleviating cell death was developed. This system resulted in accumulation of lipid in as little as 4 hr. Once compressed, porous microbeads absorb media and swell simultaneously while homogeneously inducing compression stress of microalgae. The absorbed media within beads could be supplied to adjacent cells and could minimize cell death from nutrient deficiency. All mechanotransduction was confirmed by measuring upregulation of calcium influx and Mat3 genes. The microbeads ensured robustness and controllability in repeated compression/de-compression processes. Overall, the MDLP system has potential for use as a fundamental biodiesel process that requires robustness and controllability.

  12. Dexamethasone loaded nanoparticles exert protective effects against Cisplatin-induced hearing loss by systemic administration.

    PubMed

    Sun, Changling; Wang, Xueling; Chen, Dongye; Lin, Xin; Yu, Dehong; Wu, Hao

    2016-04-21

    Ototoxicity is one of the most important adverse effects of cisplatin chemotherapy. As a common treatment of acute sensorineural hearing loss, systemic administration of steroids was demonstrated ineffective against cisplatin-induced hearing loss (CIHL) in published studies. The current study aimed to evaluate the potential protective effect of dexamethasone (DEX) encapsulated in polyethyleneglycol-coated polylactic acid (PEG-PLA) nanoparticles (DEX-NPs) against cisplatin-induced hearing loss following systemic administration. DEX was fabricated into PEG-PLA nanoparticles using emulsion and evaporation technique as previously reported. DEX or DEX-NPs was administered intraperitoneally to guinea pigs 1h before cisplatin administration. Auditory brainstem response (ABR) threshold shifts were measured at four frequencies (4, 8, 16, and 24kHz) 1 day before and three days after cisplatin injection. Cochlear morphology was examined to evaluate inner ear injury induced by cisplatin exposure. A single dose of DEX-NPs 1h before cisplatin treatment resulted in a significant preservation of the functional and structural properties of the cochlea, which was equivalent to the effect of multidose (3 days) DEX injection. In contrast, no significant protective effect was observed by single dose injection of DEX. The results of histological examination of the cochleae were consistent with the functional measurements. In conclusion, a single dose DEX-NPs significantly attenuated cisplatin ototoxicity in guinea pigs after systemic administration at both histological and functional levels indicating the potential therapeutic benefits of these nanoparticles for enhancing the delivery of DEX in acute sensorineural hearing loss.

  13. The endocannabinoid system mediates aerobic exercise-induced antinociception in rats.

    PubMed

    Galdino, Giovane; Romero, Thiago R L; Silva, José Felipe P; Aguiar, Daniele C; de Paula, Ana Maria; Cruz, Jader S; Parrella, Cosimo; Piscitelli, Fabiana; Duarte, Igor D; Di Marzo, Vincenzo; Perez, Andrea C

    2014-02-01

    Exercise-induced antinociception is widely described in the literature, but the mechanisms involved in this phenomenon are poorly understood. Systemic (s.c.) and central (i.t., i.c.v.) pretreatment with CB₁ and CB₂ cannabinoid receptor antagonists (AM251 and AM630) blocked the antinociception induced by an aerobic exercise (AE) protocol in both mechanical and thermal nociceptive tests. Western blot analysis revealed an increase and activation of CB₁ receptors in the rat brain, and immunofluorescence analysis demonstrated an increase of activation and expression of CB₁ receptors in neurons of the periaqueductal gray matter (PAG) after exercise. Additionally, pretreatment (s.c., i.t. and i.c.v.) with endocannabinoid metabolizing enzyme inhibitors (MAFP and JZL184) and an anandamide reuptake inhibitor (VDM11) prolonged and intensified this antinociceptive effect. These results indicate that exercise could activate the endocannabinoid system, producing antinociception. Supporting this hypothesis, liquid-chromatography/mass-spectrometry measurements demonstrated that plasma levels of endocannabinoids (anandamide and 2-arachidonoylglycerol) and of anandamide-related mediators (palmitoylethanolamide and oleoylethanolamide) were increased after AE. Therefore, these results suggest that the endocannabinoid system mediates aerobic exercise-induced antinociception at peripheral and central levels.

  14. Expression of Streptococcus pneumoniae Bacteriocins Is Induced by Antibiotics via Regulatory Interplay with the Competence System.

    PubMed

    Kjos, Morten; Miller, Eric; Slager, Jelle; Lake, Frank B; Gericke, Oliver; Roberts, Ian S; Rozen, Daniel E; Veening, Jan-Willem

    2016-02-01

    Pneumococcal bacteriocins (pneumocins) are antibacterial toxins that mediate intra-species competition within the human host. However, the triggers of pneumocin expression are poorly understood. Using RNA-sequencing, we mapped the regulon of the pneumocin cluster (blp) of Streptococcus pneumoniae D39. Furthermore, by analogy with pneumococcal competence, we show that several antibiotics activate the blp-genes. Using real-time gene expression measurements we show that while the promoter driving expression of the two-component regulatory system blpR/H is constitutive, the remaining blp-promoters that control pneumocin expression, immunity and the inducer peptide BlpC, are pH-dependent and induced in the late exponential phase. Intriguingly, competence for genetic transformation, mediated by the paralogous ComD/E two-component quorum system, is induced by the same environmental cues. To test for interplay between these regulatory systems, we quantified the regulatory response to the addition of synthetic BlpC and competence-stimulating peptide (CSP). Supporting the idea of such interplay, we found that immediately upon addition of CSP, the blp-promoters were activated in a comD/E-dependent manner. After a delay, blp-expression was highly induced and was strictly dependent on blpRH and blpC. This raised the question of the mechanism of BlpC export, since bioinformatic analysis showed that the genes encoding the putative exporter for BlpC, blpAB, are not intact in strain D39 and most other strains. By contrast, all sequenced pneumococcal strains contain intact comAB genes, encoding the transport system for CSP. Consistent with the idea that comAB mediate BlpC export, we finally show that high-level expression of the blp-genes requires comAB. Together, our results demonstrate that regulation of pneumocin expression is intertwined with competence, explaining why certain antibiotics induce blp-expression. Antibiotic-induced pneumocin expression might therefore have

  15. Positronium-dipole induced resonances in e +-H and e +-alkali systems

    NASA Astrophysics Data System (ADS)

    Umair, M.; Jonsell, S.

    2017-02-01

    We derive general universal scaling relations governing resonances induced by the dipole moment of excited positronium interacting with atomic ions. A single non-universal parameter, which contains all the system-dependent information, is defined. Our results are compared to numerical calculations, using complex scaling, for S, P, and D-wave resonances below the positronium n = 2 threshold in the {{e}}+-(H, Li, Na, K) systems. The energy and width ratios of the successive resonances are found to agree well with the analytically derived scaling law.

  16. Modeling the induced mutation process in bacterial cells with defects in excision repair system

    NASA Astrophysics Data System (ADS)

    Bugay, A. N.; Vasilyeva, M. A.; Krasavin, E. A.; Parkhomenko, A. Yu.

    2015-12-01

    A mathematical model of the UV-induced mutation process in Escherichia coli cells with defects in the uvrA and polA genes has been developed. The model describes in detail the reaction kinetics for the excision repair system. The number of mismatches as a result of translesion synthesis is calculated for both wild-type and mutant cells. The effect of temporal modulation of the number of single-stranded DNA during postreplication repair has been predicted. A comparison of effectiveness of different repair systems has been conducted.

  17. Electromagnetically induced transparency in a cascade-type quantum well subband system under intense picosecond excitation

    NASA Astrophysics Data System (ADS)

    Hanna, S.; Eichenberg, B.; Firsov, D. A.; Vorobjev, L. E.; Ustinov, V. M.; Seilmeier, A.

    2016-01-01

    The coherent light-matter interaction in a 4-level cascade-type subband system of an asymmetric GaAs/AlGaAs quantum well structure is studied in pump-probe transmission experiments with picosecond (ps) time resolution. Coupling two excited subbands by an intense mid-infrared laser pulse at low sample temperatures is found to result in a substantially increased transparency of the fundamental e1-e2 transition. We find a reduction of the absorption coefficient by ~80%, which is one of the most pronounced electromagnetically induced transparency in solid state systems observed so far.

  18. Derivation of Intestinal Organoids from Human Induced Pluripotent Stem Cells for Use as an Infection System.

    PubMed

    Forbester, Jessica L; Hannan, Nicholas; Vallier, Ludovic; Dougan, Gordon

    2016-08-31

    Intestinal human organoids (iHOs) provide an effective system for studying the intestinal epithelium and its interaction with various stimuli. By using combinations of different signaling factors, human induced pluripotent stem cells (hIPSCs) can be driven to differentiate down the intestinal lineage. Here, we describe the process for this differentiation, including the derivation of hindgut from hIPSCs, embedding hindgut into a pro-intestinal culture system and passaging the resulting iHOs. We then describe how to carry out microinjections to introduce bacteria to the apical side of the intestinal epithelial cells (IECs).

  19. Non-equilibrium Phenomenon between Electron and Lattice Systems Induced by the Peltier Effect

    NASA Astrophysics Data System (ADS)

    Iwasaki, Hideo; Hori, Hidenobu; Sasaki, Shosuke

    2005-08-01

    Temperature distributions of the electron and lattice systems induced by the Peltier effect have been precisely measured by improved Harman method, where the temperature differences (Δ Tel and Δ Tla) have been independently evaluated for several terminal lengths (LV) in thermoelectric materials (Bi,Sb)2Te3. Both temperature distributions have different behaviors in the stationary state, that is, the LV dependences of Δ Tel and Δ Tla show positive and negative curvatures, respectively. It is also indicated that the temperature difference has a linear relation to LV in the whole system and the observed non-equilibrium phenomenon is consistent with a law of the conservation of heat quantity.

  20. Neuroprotective effect of didymin on hydrogen peroxide-induced injury in the neuronal membrane system.

    PubMed

    Morelli, Sabrina; Piscioneri, Antonella; Salerno, Simona; Al-Fageeh, Mohamed B; Drioli, Enrico; De Bartolo, Loredana

    2014-01-01

    In this study, the flavonoid didymin was administered in vitro in neuronal cells after hydrogen peroxide (H2O2)-induced injury (neurorescue) in order to investigate the effects of this natural molecule on cell damage in a neuronal membrane system. The results showed the effects of didymin in neuronal cells by using a polycaprolactone biodegradable membrane system as an in vitro model. Two major findings are presented in this study: first is the antioxidant property of didymin and, second, for the first time we provide evidence concerning its ability to rescue neuronal cells from oxidative damage. Didymin showed radical scavenging activities and it protected the neuronal cells against H2O2-induced neurotoxicity. Didymin increased cell viability, decreased intracellular reactive oxygen species generation, stimulated superoxide dismutase, catalase and glutathione peroxidase activity in neuronal cells which were previously insulted with H2O2. In addition, didymin strikingly inhibited H2O2-induced mitochondrial dysfunctions in terms of reduction of mitochondria membrane potential and the activation of cleaved caspase-3, and also decreased dramatically the H2O2-induced phosphorylation of c-Jun N-terminal kinase. Therefore, this molecule is capable of inducing recovery from oxidative damage, and promoting and/or restoring normal cellular conditions. Moreover, the mechanism underlying the protective effects of didymin in H2O2-injured neuronal cells might be related to the activation of antioxidant defense enzymes as well as to the inhibition of apoptotic features, such as p-JNK and caspase-3 activation. These data suggest that didymin may be a potential therapeutic molecule for the treatment of neurodegenerative disorders associated with oxidative stress.

  1. Plasma membrane redox system in the control of stress-induced apoptosis.

    PubMed

    Villalba, J M; Navas, P

    2000-01-01

    The plasma membrane of animal cells contains an electron transport system based on coenzyme Q (CoQ) reductases. Cytochrome b5 reductase is NADH-specific and reduces CoQ through a one-electron reaction mechanism. DT-diaphorase also reduces CoQ, although through a two-electron reaction mechanism using both NADH and NADPH, which may be particularly important under oxidative stress conditions. Because reduced CoQ protects membranes against peroxidations, and also maintains the reduced forms of exogenous antioxidants such as alpha-tocopherol and ascorbate, this molecule can be considered a central component of the plasma membrane antioxidant system. Stress-induced apoptosis is mediated by the activation of plasma membrane-bound neutral sphingomyelinase, which releases ceramide to the cytosol. Ceramide-dependent caspase activation is part of the apoptosis pathway. The reduced components of the plasma membrane antioxidant system, mainly CoQ, prevent both lipid peroxidation and sphingomyelinase activation. This results in the prevention of ceramide accumulation and caspase 3 activation and, as consequence, apoptosis is inhibited. We propose the hypothesis that antioxidant protective function of the plasma membrane redox system can be enough to protect cells against the externally induced mild oxidative stress. If this system is overwhelmed, intracellular mechanisms of protection are required to avoid activation of the apoptosis pathway.

  2. An optically coupled system for quantitative monitoring of MRI-induced RF currents into long conductors.

    PubMed

    Zanchi, Marta G; Venook, Ross; Pauly, John M; Scott, Greig C

    2010-01-01

    The currents induced in long conductors such as guidewires by the radio-frequency (RF) field in magnetic resonance imaging (MRI) are responsible for potentially dangerous heating of surrounding media, such as tissue. This paper presents an optically coupled system with the potential to quantitatively measure the RF currents induced on these conductors. The system uses a self shielded toroid transducer and active circuitry to modulate a high speed light-emitting-diode transmitter. Plastic fiber guides the light to a photodiode receiver and transimpedance amplifier. System validation included a series of experiments with bare wires that compared wire tip heating by fluoroptic thermometers with the RF current sensor response. Validations were performed on a custom whole body 64 MHz birdcage test platform and on a 1.5 T MRI scanner. With this system, a variety of phenomena were demonstrated including cable trap current attenuation, lossy dielectric Q-spoiling and even transverse electromagnetic wave node patterns. This system should find applications in studies of MRI RF safety for interventional devices such as pacemaker leads, and guidewires. In particular, variations of this device could potentially act as a realtime safety monitor during MRI guided interventions.

  3. Light-induced fluorescence endoscopy (LIFE) imaging system for early cancer detection

    NASA Astrophysics Data System (ADS)

    Zeng, Haishan; MacAulay, Calum E.; Lam, Stephen; Palcic, Branko

    1999-09-01

    This paper summarizes our experiences on the development of a Light Induced Fluorescence Endoscopy (LIFE) imaging system for early cancer detection in the respiratory and gastrointestinal tract. The system utilizes tissue autofluorescence to provide real time video imaging of the examined organ. No exogenous fluorescent tumor markers are needed. It is used by a physician in adjunct to conventional white-light endoscopy. Suspicious areas are identified in pseudo color to guide biopsy. A multi- center clinical trial has demonstrated that in the lung, the relative sensitivity of white-light imaging + LIFE imaging vs. white-light imaging alone was 6.3 for intraepithelial neoplastic lesion detection and 2.71 when invasive carcinomas were also included. The following issues will be discussed: (1) spectroscopy study design for imaging system development; (2) architecture of the imaging systems; (3) different imaging modalities (white-light imaging, dual channel fluorescence imaging, and combined fluorescence/reflectance imaging); and (4) clinical applications.

  4. An impurity-induced gap system as a quantum data bus for quantum state transfer

    SciTech Connect

    Chen, Bing; Li, Yong; Song, Z.; Sun, C.-P.

    2014-09-15

    We introduce a tight-binding chain with a single impurity to act as a quantum data bus for perfect quantum state transfer. Our proposal is based on the weak coupling limit of the two outermost quantum dots to the data bus, which is a gapped system induced by the impurity. By connecting two quantum dots to two sites of the data bus, the system can accomplish a high-fidelity and long-distance quantum state transfer. Numerical simulations for finite system show that the numerical and analytical results of the effective coupling strength agree well with each other. Moreover, we study the robustness of this quantum communication protocol in the presence of disorder in the couplings between the nearest-neighbor quantum dots. We find that the gap of the system plays an important role in robust quantum state transfer.

  5. Long-term maintenance of human induced pluripotent stem cells by automated cell culture system

    PubMed Central

    Konagaya, Shuhei; Ando, Takeshi; Yamauchi, Toshiaki; Suemori, Hirofumi; Iwata, Hiroo

    2015-01-01

    Pluripotent stem cells, such as embryonic stem cells and induced pluripotent stem (iPS) cells, are regarded as new sources for cell replacement therapy. These cells can unlimitedly expand under undifferentiated conditions and be differentiated into multiple cell types. Automated culture systems enable the large-scale production of cells. In addition to reducing the time and effort of researchers, an automated culture system improves the reproducibility of cell cultures. In the present study, we newly designed a fully automated cell culture system for human iPS maintenance. Using an automated culture system, hiPS cells maintained their undifferentiated state for 60 days. Automatically prepared hiPS cells had a potency of differentiation into three germ layer cells including dopaminergic neurons and pancreatic cells. PMID:26573336

  6. Normally occurring intersexuality and testosterone induced plasticity in the copulatory system of adult leopard geckos.

    PubMed

    Holmes, Melissa M; Putz, Oliver; Crews, David; Wade, Juli

    2005-04-01

    The copulatory neuromuscular system of lizards is highly sexually dimorphic. Adult males possess bilateral penises called hemipenes, which are independently controlled by two muscles, the retractor penis magnus (RPM) and transversus penis (TPN). These structures are not obvious in adult females. However, in adult female leopard geckos (Eublepharis macularius), testosterone induces hemipene growth. We investigated whether these structures develop de novo in adulthood or are histologically present as rudimentary structures in the female leopard gecko. We also investigated the extent of sexual dimorphisms and plasticity in the associated neuromuscular components. To do this, we compared copulatory morphology (sizes of hemipenes, RPM and TPN muscle fibers, and associated motoneurons, as well as motoneuron and RPM fiber number) in adult females treated with testosterone, control females, and control males. All of the geckos possessed hemipenes, RPMs and TPNs, but these structures were indeed vestigial in control females. Testosterone induced striking increases in hemipene and copulatory muscle fiber size in females, but not to levels equivalent to control males. In parallel, males with increased levels of androgenic activity had larger hemipenes, suggesting naturally occurring steroid-induced plasticity. Copulatory motoneurons were not sexually dimorphic in size or number, and these measures did not respond to testosterone. The data demonstrate that the copulatory system of leopard geckos, in which gonadal sex is determined by egg incubation temperature, differs from that of many species (both reptilian and mammalian) with genotypic sex determination. Indeed, the system is remarkable in that adult females have normally occurring intersex characteristics and they exhibit substantial steroid-induced morphological plasticity in adulthood.

  7. Constitutive and inducible co-expression systems for non-viral osteoinductive gene therapy.

    PubMed

    Feichtinger, G A; Hacobian, A; Hofmann, A T; Wassermann, K; Zimmermann, A; van Griensven, M; Redl, H

    2014-02-19

    Tissue regenerative gene therapy requires expression strategies that deliver therapeutic effective amounts of transgenes. As physiological expression patterns are more complex than high-level expression of a singular therapeutic gene, we aimed at constitutive or inducible co-expression of 2 transgenes simultaneously. Co-expression of human bone morphogenetic protein 2 and 7 (BMP2/7) from constitutively expressing and doxycycline inducible plasmids was evaluated in vitro in C2C12 cells with osteocalcin reporter gene assays and standard assays for osteogenic differentiation. The constitutive systems were additionally tested in an in vivo pilot for ectopic bone formation after repeated naked DNA injection to murine muscle tissue. Inductor controlled differentiation was demonstrated in vitro for inducible co-expression. Both co-expression systems, inducible and constitutive, achieved significantly better osteogenic differentiation than single factor expression. The potency of the constitutive co-expression systems was dependent on relative expression cassette topology. In vivo, ectopic bone formation was demonstrated in 6/13 animals (46% bone formation efficacy) at days 14 and 28 in hind limb muscles as proven by in vivo µCT and histological evaluation. In vitro findings demonstrated that the devised single vector BMP2/7 co-expression strategy mediates superior osteoinduction, can be applied in an inductor controlled fashion and that its efficiency is dependent on expression cassette topology. In vivo results indicatethatco-expression of BMP2/7 applied by non-viral naked DNA gene transfer effectively mediates bone formation without the application of biomaterials, cells or recombinant growth factors, offering a promising alternative to current treatment strategies with potential for clinical translation in the future.

  8. Pump RIN-induced impairments in unrepeatered transmission systems using distributed Raman amplifier.

    PubMed

    Cheng, Jingchi; Tang, Ming; Lau, Alan Pak Tao; Lu, Chao; Wang, Liang; Dong, Zhenhua; Bilal, Syed Muhammad; Fu, Songnian; Shum, Perry Ping; Liu, Deming

    2015-05-04

    High spectral efficiency modulation format based unrepeatered transmission systems using distributed Raman amplifier (DRA) have attracted much attention recently. To enhance the reach and optimize system performance, careful design of DRA is required based on the analysis of various types of impairments and their balance. In this paper, we study various pump RIN induced distortions on high spectral efficiency modulation formats. The vector theory of both 1st and higher-order stimulated Raman scattering (SRS) effect using Jones-matrix formalism is presented. The pump RIN will induce three types of distortion on high spectral efficiency signals: intensity noise stemming from SRS, phase noise stemming from cross phase modulation (XPM), and polarization crosstalk stemming from cross polarization modulation (XPolM). An analytical model for the statistical property of relative phase noise (RPN) in higher order DRA without dealing with complex vector theory is derived. The impact of pump RIN induced impairments are analyzed in polarization-multiplexed (PM)-QPSK and PM-16QAM-based unrepeatered systems simulations using 1st, 2nd and 3rd-order forward pumped Raman amplifier. It is shown that at realistic RIN levels, negligible impairments will be induced to PM-QPSK signals in 1st and 2nd order DRA, while non-negligible impairments will occur in 3rd order case. PM-16QAM signals suffer more penalties compared to PM-QPSK with the same on-off gain where both 2nd and 3rd order DRA will cause non-negligible performance degradations. We also investigate the performance of digital signal processing (DSP) algorithms to mitigate such impairments.

  9. A fatal cytokine-induced systemic inflammatory response reveals a critical role for NK cells.

    PubMed

    Carson, W E; Yu, H; Dierksheide, J; Pfeffer, K; Bouchard, P; Clark, R; Durbin, J; Baldwin, A S; Peschon, J; Johnson, P R; Ku, G; Baumann, H; Caligiuri, M A

    1999-04-15

    The mechanism of cytokine-induced shock remains poorly understood. The combination of IL-2 and IL-12 has synergistic antitumor activity in vivo, yet has been associated with significant toxicity. We examined the effects of IL-2 plus IL-12 in a murine model and found that the daily, simultaneous administration of IL-2 and IL-12 resulted in shock and 100% mortality within 4 to 12 days depending on the strain employed. Mice treated with IL-2 plus IL-12 exhibited NK cell apoptosis, pulmonary edema, degenerative lesions of the gastrointestinal tract, and elevated serum levels of proinflammatory cytokines and acute phase reactants. The actions of TNF-alpha, IFN-gamma, macrophage-inflammatory protein-1alpha, IL-1, IL-1-converting enzyme, Fas, perforin, inducible nitric oxide synthase, and STAT1 did not contribute to the observed toxicity, nor did B or T cells. However, toxicity and death from treatment with IL-2 plus IL-12 could be completely abrogated by elimination of NK cells. These results suggest that the fatal systemic inflammatory response induced by this cytokine treatment is critically dependent upon NK cells, but does not appear to be mediated by the known effector molecules of this cellular compartment. These data may provide insight into the pathogenesis of cytokine-induced shock in humans.

  10. Mating-Induced Increase in Germline Stem Cells via the Neuroendocrine System in Female Drosophila

    PubMed Central

    Ameku, Tomotsune

    2016-01-01

    Mating and gametogenesis are two essential components of animal reproduction. Gametogenesis must be modulated by the need for gametes, yet little is known of how mating, a process that utilizes gametes, may modulate the process of gametogenesis. Here, we report that mating stimulates female germline stem cell (GSC) proliferation in Drosophila melanogaster. Mating-induced increase in GSC number is not simply owing to the indirect effect of emission of stored eggs, but rather is stimulated by a male-derived Sex Peptide (SP) and its receptor SPR, the components of a canonical neuronal pathway that induces a post-mating behavioral switch in females. We show that ecdysteroid, the major insect steroid hormone, regulates mating-induced GSC proliferation independently of insulin signaling. Ovarian ecdysteroid level increases after mating and transmits its signal directly through the ecdysone receptor expressed in the ovarian niche to increase the number of GSCs. Impairment of ovarian ecdysteroid biosynthesis disrupts mating-induced increase in GSCs as well as egg production. Importantly, feeding of ecdysteroid rescues the decrease in GSC number caused by impairment of neuronal SP signaling. Our study illustrates how female GSC activity is coordinately regulated by the neuroendocrine system to sustain reproductive success in response to mating. PMID:27310920

  11. Synthetic promoters consisting of defined cis-acting elements link multiple signaling pathways to probenazole-inducible system * #

    PubMed Central

    Zhu, Zheng; Gao, Jiong; Yang, Jin-xiao; Wang, Xiao-yan; Ren, Guo-dong; Ding, Yu-long; Kuai, Ben-ke

    2015-01-01

    Probenazole (3-allyloxy-1,2-benzisothiazole-1,1-dioxide, PBZ), the active component of Oryzemate, could induce systemic acquired resistance (SAR) in plants through the induction of salicylic acid (SA) biosynthesis. As a widely used chemical inducer, PBZ is a good prospect for establishing a new chemical-inducible system. We first designed artificially synthetic promoters with tandem copies of a single type of cis-element (SARE, JERE, GCC, GST1, HSRE, and W-box) that could mediate the expression of the β-glucuronidase (GUS) reporter gene in plants upon PBZ treatment. Then we combined different types of elements in order to improve inducibility in the PBZ-inducible system. On the other hand, we were surprised to find that the cis-elements, which are responsive to jasmonic acid (JA) and ethylene, also responded to PBZ, implying that SA, JA, and ethylene pathways also would play important roles in PBZ’s action. Further analysis demonstrated that PBZ also induced early events of innate immunity via a signaling pathway in which Ca2+ influx and mitogen-activated protein kinase (MAPK) activity were involved. We constructed synthesized artificial promoters to establish a PBZ chemical-inducible system, and preliminarily explored SA, JA, ethylene, calcium, and MAPK signaling pathways via PBZ-inducible system, which could provide an insight for in-depth study. PMID:25845359

  12. Prevention effects of Schisandra polysaccharide on radiation-induced immune system dysfunction.

    PubMed

    Zhao, Lian-Mei; Jia, Yun-Long; Ma, Ming; Duan, Yu-Qing; Liu, Li-Hua

    2015-05-01

    In this study, we investigate the efficacy of SP (Schisandra polysaccharide) in prevention of radiation-induced immune dysfunction and discussed the underlying mechanisms with a Bal/bc mouse model. The data demonstrated that SP could reverse the decreases in the number of white blood cells and lymphocytes in peripheral blood. In addition, the immunoglobulin G (IgG) and complement C3 in blood serum were all decreased after radiation and SP could restore this radiation disorder. Furthermore, SP could reverse the deregulation of CD3(+)CD4(+) and CD3(+)CD8(+) T cell subsets in peripheral blood and thymus of mice after radiotherapy. We also performed terminal dexynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) and Immunohistochemistry (IHC) to investigate the apoptosis and underlying mechanisms of SP in thymus. Data showed that radiation-induced apoptosis of thymocytes could be reversed by SP through inducing upregulation of Bcl-2 expression and downregulation of Fas and Bax levels. Furthermore, SP has no any side-effects on immunity of normal mice. In conclusion, our results indicated that SP could effectively prevent immune injury during radiotherapy by protecting the immune system. This valuable information should be of assistance in choosing a rational design for therapeutic interventions of prevention immune system damage in the radiation treatment.

  13. Variability of Inducible Expression across the Hematopoietic System of Tetracycline Transactivator Transgenic Mice

    PubMed Central

    Takiguchi, Megumi; Dow, Lukas E.; Prier, Julia E.; Carmichael, Catherine L.; Kile, Benjamin T.; Turner, Stephen J.; Lowe, Scott W.; Huang, David C. S.; Dickins, Ross A.

    2013-01-01

    The tetracycline (tet)-regulated expression system allows for the inducible overexpression of protein-coding genes, or inducible gene knockdown based on expression of short hairpin RNAs (shRNAs). The system is widely used in mice, however it requires robust expression of a tet transactivator protein (tTA or rtTA) in the cell type of interest. Here we used an in vivo tet-regulated fluorescent reporter approach to characterise inducible gene/shRNA expression across a range of hematopoietic cell types of several commonly used transgenic tet transactivator mouse strains. We find that even in strains where the tet transactivator is expressed from a nominally ubiquitous promoter, the efficiency of tet-regulated expression can be highly variable between hematopoietic lineages and between differentiation stages within a lineage. In some cases tet-regulated reporter expression differs markedly between cells within a discrete, immunophenotypically defined population, suggesting mosaic transactivator expression. A recently developed CAG-rtTA3 transgenic mouse displays intense and efficient reporter expression in most blood cell types, establishing this strain as a highly effective tool for probing hematopoietic development and disease. These findings have important implications for interpreting tet-regulated hematopoietic phenotypes in mice, and identify mouse strains that provide optimal tet-regulated expression in particular hematopoietic progenitor cell types and mature blood lineages. PMID:23326559

  14. Reversible shear-induced crystallization above equilibrium freezing temperature in a lyotropic surfactant system

    PubMed Central

    Rathee, Vikram; Krishnaswamy, Rema; Pal, Antara; Raghunathan, V. A.; Impéror-Clerc, Marianne; Pansu, Brigitte; Sood, A. K.

    2013-01-01

    We demonstrate a unique shear-induced crystallization phenomenon above the equilibrium freezing temperature in weakly swollen isotropic and lamellar mesophases with bilayers formed in a cationic-anionic mixed surfactant system. Synchrotron rheological X-ray diffraction study reveals the crystallization transition to be reversible under shear (i.e., on stopping the shear, the nonequilibrium crystalline phase melts back to the equilibrium mesophase). This is different from the shear-driven crystallization below , which is irreversible. Rheological optical observations show that the growth of the crystalline phase occurs through a preordering of the phase to an phase induced by shear flow, before the nucleation of the phase. Shear diagram of the phase constructed in the parameter space of shear rate vs. temperature exhibits and transitions above the equilibrium crystallization temperature , in addition to the irreversible shear-driven nucleation of in the phase below . In addition to revealing a unique class of nonequilibrium phase transition, the present study urges a unique approach toward understanding shear-induced phenomena in concentrated mesophases of mixed amphiphilic systems. PMID:23986497

  15. High-Pressure Induced New Phases and Properties in Typical Molecular Systems

    NASA Astrophysics Data System (ADS)

    Cui, Tian

    2013-06-01

    High pressure introduces new phases by the rearrangement of atoms and reconfigurations of electronic states in materials, often with new physical and chemical phenomena. Study of the new phases in typical molecular systems under high pressure is an interesting subject, such as energy storage materials of solid hydrogen and polymeric nitrogen, hydrogen-rich compound with high-Tc superconductivity under high pressure, high pressure induced metallization of hydrogen, etc. High-pressure structures and pressure-induced phase transitions in the typical molecular solids, such as solid iodine, CHBr3, N2/CN, HBr/HCl, hydrogen-rich compounds (H2S, ZrH2, AsH3, BaReH9, etc.), and group IVA hydrides (Si2H6, Ge2H6, Sn2H6, etc.) are investigated extensively by means of first-principles density functional theory and extensive prediction strategies (molecular dynamics simulation, simulated annealing, soft mode phase transition, random structure-searching method and evolutionary methodology etc.). The new structures and new properties derived from pressure-induced phase transitions in these typical molecular systems have been observed. It is showed that high pressure provides a path for producing new materials with new properties.

  16. Thymoquinone ameliorates lead-induced suppression of the antioxidant system in rat kidneys

    PubMed Central

    Mabrouk, Aymen; Cheikh, Hassen Ben

    2016-01-01

    Objective Alteration of the antioxidant status in the kidneys may be related to lead (Pb) intoxication. The present study aimed to investigate the possible beneficial effect of thymoquinone (TQ), the major active ingredient of the volatile oil of Nigella sativa seeds, on Pb-induced renal antioxidant defense system impairment. Methods A total of thirty two healthy adult male Wistar rats were randomly divided into four equal groups as follows: a control group, which received no treatment; a Pb group, which was exposed to 2,000 ppm of Pb acetate in drinking water; a Pb-TQ group, which was cotreated with Pb plus TQ (5 mg/kg/day, per os); and a TQ group receiving only TQ. All treatments were applied for five weeks. Results TQ alone did not induce any significant changes in the antioxidant defense system. By contrast, Pb exposure significantly decreased reduced glutathione level and superoxide dismutase, glutathione peroxidase, catalase, and glutathione reductase activities in the renal tissue. Interestingly, supplementation with TQ significantly improved the affected antioxidant parameters. Conclusion Our data are the first to provide evidence on the protective effect of TQ against Pb-induced renal antioxidant capacity impairment and suggest that this component might be a clinically promising alternative in Pb nephrotoxicity. PMID:27052350

  17. Seismic Hazard Analysis as a Controlling Technique of Induced Seismicity in Geothermal Systems

    NASA Astrophysics Data System (ADS)

    Convertito, V.; Sharma, N.; Maercklin, N.; Emolo, A.; Zollo, A.

    2011-12-01

    The effect of induced seismicity of geothermal systems during stimulation and fluid circulation can cover a wide range of values from light and unfelt to severe and damaging. If the design of a modern geothermal system requires the largest efficiency to be obtained from the social point of view it is required that the system could be managed in order to reduce possible impact in advance. In this framework, automatic control of the seismic response of the stimulated reservoir is nowadays mandatory, particularly in proximity of densely populated areas. Recently, techniques have been proposed for this purpose mainly based on the concept of the traffic light. This system provides a tool to decide the level of stimulation rate based on the real-time analysis of the induced seismicity and the ongoing ground motion values. However, in some cases the induced effect can be delayed with respect to the time when the reservoir is stimulated. Thus, a controlling system technique able to estimate the ground motion levels for different time scales can help to better control the geothermal system. Here we present an adaptation of the classical probabilistic seismic hazard analysis to the case where the seismicity rate as well as the propagation medium properties are not constant with time. We use a non-homogeneous seismicity model for modeling purposes, in which the seismicity rate and b-value of the recurrence relationship change with time. Additionally, as a further controlling procedure, we propose a moving time window analysis of the recorded peak ground-motion values aimed at monitoring the changes in the propagation medium. In fact, for the same set of magnitude values recorded at the same stations, we expect that on average peak ground motion values attenuate in same way. As a consequence, the residual differences can be reasonably ascribed to changes in medium properties. These changes can be modeled and directly introduced in the hazard integral. We applied the proposed

  18. A Wireless Intracranial Brain Deformation Sensing System for Blast-Induced Traumatic Brain Injury

    PubMed Central

    Song, S.; Race, N. S.; Kim, A.; Zhang, T.; Shi, R.; Ziaie, B.

    2015-01-01

    Blast-induced traumatic brain injury (bTBI) has been linked to a multitude of delayed-onset neurodegenerative and neuropsychiatric disorders, but complete understanding of their pathogenesis remains elusive. To develop mechanistic relationships between bTBI and post-blast neurological sequelae, it is imperative to characterize the initiating traumatic mechanical events leading to eventual alterations of cell, tissue, and organ structure and function. This paper presents a wireless sensing system capable of monitoring the intracranial brain deformation in real-time during the event of a bTBI. The system consists of an implantable soft magnet and an external head-mounted magnetic sensor that is able to measure the field in three dimensions. The change in the relative position of the soft magnet WITH respect to the external sensor as the result of the blast wave induces changes in the magnetic field. The magnetic field data in turn is used to extract the temporal and spatial motion of the brain under the blast wave in real-time. The system has temporal and spatial resolutions of 5 μs and 10 μm. Following the characterization and validation of the sensor system, we measured brain deformations in a live rodent during a bTBI. PMID:26586273

  19. Transmission stability and Raman-induced amplitude dynamics in multichannel soliton-based optical waveguide systems

    NASA Astrophysics Data System (ADS)

    Peleg, Avner; Nguyen, Quan M.; Tran, Thinh P.

    2016-12-01

    We study transmission stability and dynamics of pulse amplitudes in N-channel soliton-based optical waveguide systems, taking into account second-order dispersion, Kerr nonlinearity, delayed Raman response, and frequency dependent linear gain-loss. We carry out numerical simulations with systems of N coupled nonlinear Schrödinger (NLS) equations and compare the results with the predictions of a simplified predator-prey model for Raman-induced amplitude dynamics. Coupled-NLS simulations for single-fiber transmission with 2 ≤ N ≤ 4 frequency channels show stable oscillatory dynamics of soliton amplitudes at short-to-intermediate distances, in excellent agreement with the predator-prey model's predictions. However, at larger distances, we observe transmission destabilization due to resonant formation of radiative sidebands, which is caused by Kerr nonlinearity. The presence of linear gain-loss in a single fiber leads to a limited increase in transmission stability. Significantly stronger enhancement of transmission stability is achieved in a nonlinear N-waveguide coupler due to efficient suppression of radiative sideband generation by the linear gain-loss. As a result, the distances along which stable Raman-induced dynamics of soliton amplitudes is observed are significantly larger in the waveguide coupler system compared with the single-fiber system.

  20. Autophagy Genes Enhance Murine Gammaherpesvirus 68 Reactivation From Latency by Preventing Virus-induced Systemic Inflammation

    PubMed Central

    Park, Sunmin; Buck, Michael D.; Desai, Chandni; Zhang, Xin; Loginicheva, Ekaterina; Martinez, Jennifer; Freeman, Michael L.; Saitoh, Tatsuya; Akira, Shizuo; Guan, Jun-Lin; He, You-Wen; Blackman, Marcia A.; Handley, Scott A.; Levine, Beth; Green, Douglas R.; Reese, Tiffany A.; Artyomov, Maxim N.; Virgin, Herbert W.

    2016-01-01

    SUMMARY Host genes that regulate systemic inflammation upon chronic viral infection are incompletely understood. Murine γ-herpesvirus 68 (MHV68) infection is characterized by latency in macrophages, and reactivation is inhibited by Interferon-γ (IFN-γ). Using a Lysozyme-M-cre (LysMcre) expression system, we show that deletion of autophagy-related (Atg) genes Fip200, beclin 1, Atg14, Atg16L1, Atg7, Atg3, and Atg5, in the myeloid compartment, inhibited MHV68 reactivation in macrophages. Atg5-deficiency did not alter reactivation from B cells, and effects on reactivation from macrophages were not explained by alterations in productive viral replication or the establishment of latency. Rather, chronic MHV68 infection triggered increased systemic inflammation, increased T cell production of IFN-γ and an IFN-γ-induced transcriptional signature in macrophages from Atg gene-deficient mice. The Atg5-related reactivation defect was partially reversed by neutralization of IFN-γ. Thus Atg genes in myeloid cells dampen virus-induced systemic inflammation, creating an environment that fosters efficient MHV68 reactivation from latency. PMID:26764599

  1. Immune System Modifications Induced in a Mouse Model of Chronic Exposure to (90)Sr.

    PubMed

    Synhaeve, Nicholas; Musilli, Stefania; Stefani, Johanna; Nicolas, Nour; Delissen, Olivia; Dublineau, Isabelle; Bertho, Jean-Marc

    2016-03-01

    Strontium 90 ((90)Sr) remains in the environment long after a major nuclear disaster occurs. As a result, populations living on contaminated land are potentially exposed to daily ingesting of low quantities of (90)Sr. The potential long-term health effects of such chronic contamination are unknown. In this study, we used a mouse model to evaluate the effects of (90)Sr ingestion on the immune system, the animals were chronically exposed to (90)Sr in drinking water at a concentration of 20 kBq/l, for a daily ingestion of 80-100 Bq/day. This resulted in a reduced number of CD19(+) B lymphocytes in the bone marrow and spleen in steady-state conditions. In contrast, the results from a vaccine experiment performed as a functional test of the immune system showed that in response to T-dependent antigens, there was a reduction in IgG specific to tetanus toxin (TT), a balanced Th1/Th2 response inducer antigen, but not to keyhole limpet hemocyanin (KLH), a strong Th2 response inducer antigen. This was accompanied by a reduction in Th1 cells in the spleen, consistent with the observed reduction in specific IgG concentration. The precise mechanisms by which (90)Sr acts on the immune system remain to be elucidated. However, our results suggest that (90)Sr ingestion may be responsible for some of the reported effects of internal contamination on the immune system in civilian populations exposed to the Chernobyl fallout.

  2. Phase transition induced by a shock wave in hard-sphere and hard-disk systems.

    PubMed

    Zhao, Nanrong; Sugiyama, Masaru; Ruggeri, Tommaso

    2008-08-07

    Dynamic phase transition induced by a shock wave in hard-sphere and hard-disk systems is studied on the basis of the system of Euler equations with caloric and thermal equations of state. First, Rankine-Hugoniot conditions are analyzed. The quantitative classification of Hugoniot types in terms of the thermodynamic quantities of the unperturbed state (the state before a shock wave) and the shock strength is made. Especially Hugoniot in typical two possible cases (P-1 and P-2) of the phase transition is analyzed in detail. In the case P-1 the phase transition occurs between a metastable liquid state and a stable solid state, and in the case P-2 the phase transition occurs through coexistence states, when the shock strength changes. Second, the admissibility of the two cases is discussed from a viewpoint of the recent mathematical theory of shock waves, and a rule with the use of the maximum entropy production rate is proposed as the rule for selecting the most probable one among the possible cases, that is, the most suitable constitutive equation that predicts the most probable shock wave. According to the rule, the constitutive equation in the case P-2 is the most promising one in the dynamic phase transition. It is emphasized that hard-sphere and hard-disk systems are suitable reference systems for studying shock wave phenomena including the shock-induced phase transition in more realistic condensed matters.

  3. Engineered absorption enhancement and induced transparency in coupled molecular and plasmonic resonator systems.

    PubMed

    Adato, Ronen; Artar, Alp; Erramilli, Shyamsunder; Altug, Hatice

    2013-06-12

    Coupled plasmonic resonators have become the subject of significant research interest in recent years as they provide a route to dramatically enhanced light-matter interactions. Often, the design of these coupled mode systems draws intuition and inspiration from analogies to atomic and molecular physics systems. In particular, they have been shown to mimic quantum interference effects, such as electromagnetically induced transparency (EIT) and Fano resonances. This analogy also been used to describe the surface-enhanced absorption effect where a plasmonic resonance is coupled to a weak molecular resonance. These important phenomena are typically described using simple driven harmonic (or linear) oscillators (i.e., mass-on-a-spring) coupled to each other. In this work, we demonstrate the importance of an essential interdependence between the rate at which the system can be driven by an external field and its damping rate through radiative loss. This link is required in systems exhibiting time-reversal symmetry and energy conservation. Not only does it ensure an accurate and physically consistent description of resonant systems but leads directly to interesting new effects. Significantly, we demonstrate this dependence to predict a transition between EIT and electromagnetically induced absorption that is solely a function of the ratio of the radiative to intrinsic loss rates in coupled resonator systems. Leveraging the temporal coupled mode theory, we introduce a unique and intuitive picture that accurately describes these effects in coupled plasmonic/molecular and fully plasmonic systems. We demonstrate our approach's key features and advantages analytically as well as experimentally through surface-enhanced absorption spectroscopy and plasmonic metamaterial applications.

  4. Deciphering the hormonal signalling network behind the systemic resistance induced by Trichoderma harzianum in tomato

    PubMed Central

    Martínez-Medina, Ainhoa; Fernández, Iván; Sánchez-Guzmán, María J.; Jung, Sabine C.; Pascual, Jose A.; Pozo, María J.

    2013-01-01

    Root colonization by selected Trichoderma isolates can activate in the plant a systemic defense response that is effective against a broad-spectrum of plant pathogens. Diverse plant hormones play pivotal roles in the regulation of the defense signaling network that leads to the induction of systemic resistance triggered by beneficial organisms [induced systemic resistance (ISR)]. Among them, jasmonic acid (JA) and ethylene (ET) signaling pathways are generally essential for ISR. However, Trichoderma ISR (TISR) is believed to involve a wider variety of signaling routes, interconnected in a complex network of cross-communicating hormone pathways. Using tomato as a model, an integrative analysis of the main mechanisms involved in the systemic resistance induced by Trichoderma harzianum against the necrotrophic leaf pathogen Botrytis cinerea was performed. Root colonization by T. harzianum rendered the leaves more resistant to B. cinerea independently of major effects on plant nutrition. The analysis of disease development in shoots of tomato mutant lines impaired in the synthesis of the key defense-related hormones JA, ET, salicylic acid (SA), and abscisic acid (ABA), and the peptide prosystemin (PS) evidenced the requirement of intact JA, SA, and ABA signaling pathways for a functional TISR. Expression analysis of several hormone-related marker genes point to the role of priming for enhanced JA-dependent defense responses upon pathogen infection. Together, our results indicate that although TISR induced in tomato against necrotrophs is mainly based on boosted JA-dependent responses, the pathways regulated by the plant hormones SA- and ABA are also required for successful TISR development. PMID:23805146

  5. Surveillance of systemic trafficking of macrophages induced by UHMWPE particles in nude mice by noninvasive imaging.

    PubMed

    Ren, Pei-Gen; Huang, Zhinong; Ma, Ting; Biswal, Sandip; Smith, Robert L; Goodman, Stuart B

    2010-09-01

    Macrophages constitute a major part of the cell response to wear particles produced at articulating and nonarticulating interfaces of joint replacements. This foreign body reaction can result in periprosthetic osteolysis and implant loosening. We demonstrate that ultra-high molecular weight polyethylene (UHMWPE) particles induce systemic trafficking of macrophages by noninvasive in vivo imaging and immunohistochemistry. The distal femora of nude mice were injected with 60 mg/mL UHMWPE suspension or saline alone. Reporter RAW264.7 macrophages that stably expressed the bioluminescent reporter gene and the fluorescence reporter gene were injected intravenously. Bioluminescence imaging was performed using an in vivo imaging system immediately after macrophage injection and at 2-day intervals. Compared with the nonoperated contralateral femora, at day 4, 6, and 8, the bioluminescent signal of femora containing UHMWPE suspension increased 1.30 +/- 0.09-, 2.36 +/- 0.92-, and 10.32 +/- 7.61-fold, respectively. The values at same time points for saline-injected control group were 1.08 +/- 0.07-, 1.14 +/- 0.27-, and 1.14 +/- 0.35-fold, respectively. The relative bioluminescence of the UHMWPE group was higher at all postinjection days and significantly greater than the saline group at day 8 (p < 0.05). Histological analysis confirmed the presence of reporter macrophages within the medullary canal of mice with implanted UHMWPE particles. The presence of UHMWPE particles induced enhanced bone remodeling activity. Clinically relevant UHMWPE particles stimulated the systemic recruitment of macrophages during an early time course using the murine femoral implant model. Interference with systemic macrophage trafficking may potentially mitigate UHMWPE particle-induced periprosthetic osteolysis.

  6. Deciphering the hormonal signalling network behind the systemic resistance induced by Trichoderma harzianum in tomato.

    PubMed

    Martínez-Medina, Ainhoa; Fernández, Iván; Sánchez-Guzmán, María J; Jung, Sabine C; Pascual, Jose A; Pozo, María J

    2013-01-01

    Root colonization by selected Trichoderma isolates can activate in the plant a systemic defense response that is effective against a broad-spectrum of plant pathogens. Diverse plant hormones play pivotal roles in the regulation of the defense signaling network that leads to the induction of systemic resistance triggered by beneficial organisms [induced systemic resistance (ISR)]. Among them, jasmonic acid (JA) and ethylene (ET) signaling pathways are generally essential for ISR. However, Trichoderma ISR (TISR) is believed to involve a wider variety of signaling routes, interconnected in a complex network of cross-communicating hormone pathways. Using tomato as a model, an integrative analysis of the main mechanisms involved in the systemic resistance induced by Trichoderma harzianum against the necrotrophic leaf pathogen Botrytis cinerea was performed. Root colonization by T. harzianum rendered the leaves more resistant to B. cinerea independently of major effects on plant nutrition. The analysis of disease development in shoots of tomato mutant lines impaired in the synthesis of the key defense-related hormones JA, ET, salicylic acid (SA), and abscisic acid (ABA), and the peptide prosystemin (PS) evidenced the requirement of intact JA, SA, and ABA signaling pathways for a functional TISR. Expression analysis of several hormone-related marker genes point to the role of priming for enhanced JA-dependent defense responses upon pathogen infection. Together, our results indicate that although TISR induced in tomato against necrotrophs is mainly based on boosted JA-dependent responses, the pathways regulated by the plant hormones SA- and ABA are also required for successful TISR development.

  7. Role of brain dopaminergic system in the adrenomedullin-induced diuresis and natriuresis.

    PubMed

    Díaz, Emilia; Silva, María; Israel, Anita

    2003-11-01

    Intracerebroventricular (IVT) administration of adrenomedullin (AM) to conscious male hydrated rats increases urinary volume and sodium excretion. The possible involvement of brain dopamine (DA) system on the renal action of IVT-AM was investigated. AM-induced diuretic and natriuretic action was prevented following selective central dopaminergic denervation with 6-hydroxydopamine (6OHDA) in combination with desmethylimipramine (DMI). Selective D(2) DA receptor antagonism with haloperidol, sulpiride, and remoxipride; or with the D(1) DA receptor antagonist, SCH 23390, blunted the increase in urinary volume and sodium excretion induced by IVT-AM. The present results suggest that AM acts centrally, at least in part, via an interaction with endogenous DA through the activation of both DA D(1)/D(2) receptor subtype.

  8. Squeezing induced high-efficiency diffraction grating in two-level system.

    PubMed

    Cheng, Guang-Ling; Chen, Ai-Xi

    2017-02-20

    We show the effect of squeezed vacuum on laser-induced grating in a weak standing-wave-driving two-level atomic system. Using the optical Bloch equation and the Floquet harmonic expansion, we obtain the linear response of the medium with respect to the probe field, which determines the transmission spectrum and diffraction intensity. At the presence of the squeezing, the grating with large intensity both in the first- and higher-order directions can be obtainable even though the driving is relatively weak. The responsible mechanism is due to squeezing-induced gain accompanied by the large dispersion. Based on the spatial gain and phase modulations, the first- and high-order diffraction intensities simultaneously could have the large values. Such a scheme we present could have potential applications in implementing lensless imaging and developing the photon devices in quantum information processing.

  9. Induced cholesteric systems based on some cyano derivatives as host phases

    NASA Astrophysics Data System (ADS)

    Shkolnikova, Natalya I.; Kutulya, Lidiya A.; Vashchenko, V. V.; Fedoryako, A. P.; Lapanik, V. I.; Posledovich, N. R.

    2002-12-01

    Macroscopical properties of some induced cholesteric compositions based on 4-pentyl-4'-cyano derivatives of biphenyl and phenylcyclohexane as host phases have been investigated. The series of N-arylidene derivatives of (S)-1-phenylethylamine with varied both rigid moiety of the N-arylidene fragment and terminal substituent was used as chiral dopants. The influence of the chiral dopant molecular structure as well as of physical properties of the host phases used on the helical twisting power, the temperature dependence of the induced helical pitch and the N* mesophase thermal stability has been characterized. It has been concluded that the distinctions in properties of the LC systems containing the OCH2 and COO linking groups are caused by their different conformational states.

  10. Reversal of hepatitis B virus-induced systemic immune tolerance by intrinsic innate immune stimulation.

    PubMed

    Han, Qiuju; Lan, Peixiang; Zhang, Jian; Zhang, Cai; Tian, Zhigang

    2013-08-01

    Systemic immune tolerance induced by chronic hepatitis B virus (HBV) infection is a significant question, but the mechanism of which remains unclear. In this mini-review, we summarize the impaired innate and adaptive immune responses involved in immune tolerance in chronic HBV infection. Furthermore, we delineate a novel dual functional small RNA to inhibit HBV replication and stimulate innate immunity against HBV, which proposed a promising immunotherapeutic intervention to interrupt HBV-induced immunotolerance. A mouse model of HBV persistence was established and used to observe the immune tolerant to HBV vaccination, the cell-intrinsic immune tolerance of which might be reversed by chemically synthesized dual functional small RNA (3p-hepatitis B Virus X gene [HBx]-small interfering RNA) in vitro experiments and by biologically constructed dual functional vector (single-stranded RNA-HBx- short hairpin RNA) in vivo experiment using HBV-carrier mice.

  11. Diet-induced hypercholesterolemia impaired testicular steroidogenesis in mice through the renin-angiotensin system.

    PubMed

    Martínez-Martos, José M; Arrazola, Marce; Mayas, María D; Carrera-González, María P; García, María J; Ramírez-Expósito, María J

    2011-08-01

    Hypercholesterolemia and low testosterone concentrations in men are associated with a high risk factor for atherosclerosis. It is known that cholesterol serves as the major precursor for the synthesis of the sex hormones. The bioactive peptides of the renin-angiotensin-system localized in the gonads play a key role in the relation between cholesterol and testosterone by modulating steroidogenesis and inhibiting testosterone production. In the present work, we evaluated the effects of diet-induced hypercholesterolemia on circulating testosterone levels and its relationship with the testicular RAS-regulating specific aminopeptidase activities in male mouse. A significant decrease in serum circulating levels of testosterone was observed after induced hypercholesterolemia. The changes found in aminopeptidase activities suggest a role of Ang III and Ang IV in the regulation of steroidogenesis.

  12. Photonic lattice simulation of dissipation-induced correlations in bosonic systems

    PubMed Central

    Rai, Amit; Lee, Changhyoup; Noh, Changsuk; Angelakis, Dimitris G.

    2015-01-01

    We propose an optical simulation of dissipation-induced correlations in one-dimensional (1D) interacting bosonic systems, using a two-dimensional (2D) array of linear photonic waveguides and only classical light. We show that for the case of two bosons in a 1D lattice, one can simulate on-site two-body dissipative dynamics using a linear 2D waveguide array with lossy diagonal waveguides. The intensity distribution of the propagating light directly maps out the wave function, allowing one to observe the dissipation-induced correlations with simple measurements. Beyond the on-site model, we also show that a generalised model containing nearest-neighbour dissipative interaction can be engineered and probed in the proposed set-up. PMID:25708778

  13. Numerical analysis of noise-induced oscillating bistability in a prey-predator plankton system

    NASA Astrophysics Data System (ADS)

    Ryashko, Lev

    2013-10-01

    Stochastic cycles of the Truscott-Brindley (TB) model for predator-prey plankton system are studied. For weak noise, random trajectories are concentrated in the small neighborhood of the unforced deterministic cycle. As the noise intensity increases, in the Canard-like cycles zone of the TB model, the stochastic trajectories begin to split into two parts. This new noise-induced phenomenon is investigated using numerical simulation of random trajectories and stochastic sensitivity functions (SSF) technique. It is shown that the intensity of noise generating this splitting bifurcation significantly depends on the stochastic sensitivity of cycles. Using the SSF technique, we find a critical value of the parameter corresponding to the supersensitive cycle. For this critical value, a comparative parametrical analysis of the stochastic cycle splitting is presented. An interplay of this noise-induced phenomenon with local instability of Canard cycles is discussed.

  14. Boundary-induced dynamics in one-dimensional topological systems and memory effects of edge modes

    NASA Astrophysics Data System (ADS)

    He, Yan; Chien, Chih-Chun

    2016-07-01

    Dynamics induced by a change of boundary conditions reveals rate-dependent signatures associated with topological properties in one-dimensional Kitaev chain and SSH model. While the perturbation from a change of the boundary propagates into the bulk, the density of topological edge modes in the case of transforming to open boundary condition reaches steady states. The steady-state density depends on the transformation rate of the boundary and serves as an illustration of quantum memory effects in topological systems. Moreover, while a link is physically broken as the boundary condition changes, some correlation functions can remain finite across the broken link and keep a record of the initial condition. By testing those phenomena in the nontopological regimes of the two models, none of the interesting signatures of memory effects can be observed. Our results thus contrast the importance of topological properties in boundary-induced dynamics.

  15. Induced-charge electrokinetics, bipolar current, and concentration polarization in a microchannel-Nafion-membrane system

    NASA Astrophysics Data System (ADS)

    Park, Sinwook; Yossifon, Gilad

    2016-06-01

    The presence of a floating electrode array located within the depletion layer formed due to concentration polarization across a microchannel-membrane interface device may produce not only induced-charge electro-osmosis (ICEO) but also bipolar current resulting from the induced Faradaic reaction. It has been shown that there exists an optimal thickness of a thin dielectric coating that is sufficient to suppress bipolar currents but still enables ICEO vortices that stir the depletion layer, thereby affecting the system's current-voltage response. In addition, the use of alternating-current electro-osmosis by activating electrodes results in further enhancement of the fluid stirring and opens new routes for on-demand spatiotemporal control of the depletion layer length.

  16. Conditional control of dendritic cell factor 1 expression by a tetracycline-inducible system.

    PubMed

    Yan, H; Huang, C; Yang, M; Guo, J; Wang, J; Feng, R; Wen, T

    2015-05-08

    Dendritic cell factor 1 plays important roles in neural stem cells differentiation and in glioma cells proliferation, migration, and invasion. Here, we used a tetracycline—inducible system that regulates the expression of Dendritic cell factor 1 in glioma cells. We constructed two tet—inducible vectors, pTRE—EGFP—DCF1 and pTRE—LJM1—DCF1, by modifying the promoter PCMV. In the absence of tetracycline or doxycycline, the expression of Dendritic cell factor 1 in cells co—transfected with pTRE—EGFP—DCF1 or pTRE—LJM1—EGFP—DCF1 and ptTS—Neo was suppressed through binding of the tetracyline—controlled transcriptional suppressor to tetracycline response element, and the suppression was released by the addition of doxycycline. Our work has laid foundations for potential clinical application of cancer therapy in realizing artificial regulation of gene.

  17. Novel features of an inducible defense system in larval tree frogs (Hyla chrysoscelis).

    PubMed

    Richardson, Jonathan L

    2006-03-01

    Organisms in aquatic ecosystems must often tolerate variable environmental conditions, including an uncertain risk of predation. Individuals that can maintain plastic defenses against predation will increase their survival when predators are present, but will not incur the costs of these defenses when the risk of predation is low and the defense is not induced. Larvae of the pond-breeding anuran Hyla chrysoscelis develop a conspicuous phenotype in the presence of predators consisting of a brightly colored tail and a deeper tail fin. In this study, I attempted to identify the source of the chemical signal that induces this defensive morphology in this species. I tested whether metabolites alone, originating from the prey but passing through the predator, were able to induce the same morphological response as the combination of alarm signals released directly by attacked conspecifics, and metabolites. I used morphometric and tail conspicuousness data to assess tadpole response to the perceived risk of predation by larval odonate predators (Anax junius). I also tested whether this inducing cue could be recognized across species by measuring the morphological response of H. chrysoscelis tadpoles exposed to cues emitted when tadpoles of a closely related genus (Pseudacris crucifer) were consumed. Tadpoles exhibited a clean graded response of both overall shape and tail morphology in response to all cues, corresponding to their relative reliability as indicators of a risk of predation. H. chrysoscelis tadpoles were also able to respond to cues emitted when tadpoles of a closely related genus were consumed by predators. These results illustrate that tadpoles of this species are able to respond to metabolites alone without alarm signals, and that interspecific chemical communication is a primary mechanism for predator avoidance in this inducible defense system.

  18. Effect of systemic infection induced by Pseudomonas aeruginosa on the brain uptake of colistin in mice.

    PubMed

    Jin, Liang; Li, Jian; Nation, Roger L; Nicolazzo, Joseph A

    2012-10-01

    In view of reports of colistin-induced neurotoxicity in infected patients, the aim of this study was to assess whether the integrity of the blood-brain barrier (BBB) and the brain uptake of colistin are altered in the presence of systemic Pseudomonas aeruginosa infection. Bacteremia was confirmed 8 h after intramuscular administration of P. aeruginosa ATCC 27853 to Swiss Outbred mice, at which time a single subcutaneous dose of colistin sulfate (40 mg/kg of body weight) or an intravenous dose of [(14)C]sucrose (2 μCi) was administered. Despite a substantial elevation in plasma levels of the proinflammatory cytokines tumor necrosis factor alpha, interleukin-1β, and interleukin-6 during bacterial infection, the brain uptake of colistin was similar between infected and noninfected mice with AUC(brain)/AUC(plasma) (where AUC(brain) is the area under the brain concentration-time curve and AUC(plasma) is the area under the plasma concentration-time curve) ratios of 0.023 and 0.024, respectively. Similarly, the brain-to-plasma ratios of [(14)C]sucrose were no different between infected and noninfected mice, consistent with a lack of effect of bacteremia on BBB integrity. To further correlate any relationship between BBB disruption and plasma levels of proinflammatory cytokines, BBB integrity, colistin brain uptake, and plasma proinflammatory cytokines were measured following the administration of Salmonella enterica lipopolysaccharide (LPS), an agent known to induce BBB disruption. Despite LPS inducing a 4-fold increase in colistin brain uptake and a significant (P < 0.05) 1.2-fold increase in [(14)C]sucrose BBB penetration, plasma cytokine levels were lower with LPS treatment relative to those obtained with bacterial infection with P. aeruginosa. This study demonstrates that the brain uptake of colistin is not increased in mice during P. aeruginosa-induced systemic bacteremia despite a significant increase in plasma levels of three proinflammatory cytokines.

  19. Consolidated Laser-Induced Fluorescence Diagnostic Systems for the NASA Ames Arc Jet Facilities

    NASA Technical Reports Server (NTRS)

    Grinstead, Jay H.; Wilder, Michael C.; Porter, Barry J.; Brown, Jeffrey D.; Yeung, Dickson; Battazzo, Stephen J.; Brubaker, Timothy R.

    2016-01-01

    The spectroscopic diagnostic technique of two photon absorption laser-induced fluorescence (TALIF) of atomic species for non-intrusive arc jet flow property measurement was first implemented at NASA Ames in the mid-1990s. Use of TALIF expanded at NASA Ames and to NASA Johnson's arc jet facility in the late 2000s. In 2013-2014, NASA combined the agency's large-scale arc jet test capabilities at NASA Ames. Concurrent with that effort, the agency also sponsored a project to establish two comprehensive LIF diagnostic systems for the Aerodynamic Heating Facility (AHF) and Interaction Heating Facility (IHF) arc jets. The scope of the project enabled further engineering development of the existing IHF LIF system as well as the complete reconstruction of the original AHF LIF system. The updated LIF systems are identical in design and capability. They represent the culmination of over 20 years of development experience in transitioning a specialized laboratory research tool into a measurement system for large-scale, high-demand test facilities. This paper documents the overall system design from measurement requirements to implementation. Representative data from the redeveloped AHF and IHF LIF systems are also presented.

  20. Consolidated Laser-Induced Fluorescence Diagnostic Systems for the NASA Ames Arc Jet Facilities

    NASA Technical Reports Server (NTRS)

    Grinstead, Jay H.; Wilder, Michael C.; Porter, Barry J.; Brown, Jeffrey D.; Yeung, Dickson; Battazzo, Stephen J.; Brubaker, Timothy R.

    2016-01-01

    The spectroscopic diagnostic technique of two photon absorption laser-induced fluorescence (LIF) of atomic species for non-intrusive arc jet flow property measurement was first implemented at NASA Ames in the mid-1990s. In 2013-2014, NASA combined the agency's large-scale arc jet test capabilities at NASA Ames. Concurrent with that effort, the agency also sponsored a project to establish two comprehensive LIF diagnostic systems for the Aerodynamic Heating Facility (AHF) and Interaction Heating Facility (IHF) arc jets. The scope of the project enabled further engineering development of the existing IHF LIF system as well as the complete reconstruction of the AHF LIF system. The updated LIF systems are identical in design and capability. They represent the culmination of over 20 years of development experience in transitioning a specialized laboratory research tool into a measurement system for large-scale, high-demand test facilities. This paper will document the latest improvements of the LIF system design and demonstrations of the redeveloped AHF and IHF LIF systems.

  1. Consolidated Laser-Induced Fluorescence Diagnostic Systems for the NASA Ames Arc Jet Facilities

    NASA Technical Reports Server (NTRS)

    Grinstead, Jay; Wilder, Michael C.; Porter, Barry; Brown, Jeff; Yeung, Dickson; Battazzo, Steve; Brubaker, Tim

    2016-01-01

    The spectroscopic diagnostic technique of two photon absorption laser-induced fluorescence (TALIF) of atomic species for non-intrusive arc jet flow property measurement was first implemented at NASA Ames in the mid-1990s. Use of TALIF expanded at NASA Ames and to NASA Johnsons arc jet facility in the late 2000s. In 2013-2014, NASA combined the agency's large-scale arc jet test capabilities at NASA Ames. Concurrent with that effort, the agency also sponsored a project to establish two comprehensive LIF diagnostic systems for the Aerodynamic Heating Facility (AHF) and Interaction Heating Facility (IHF) arc jets. The scope of the project enabled further engineering development of the existing IHF LIF system as well as the complete reconstruction of the original AHF LIF system. The updated LIF systems are identical in design and capability. They represent the culmination of over 20 years of development experience in transitioning a specialized laboratory research tool into a measurement system for large-scale, high-demand test facilities. This paper documents the overall system design from measurement requirements to implementation. Representative data from the redeveloped AHF and IHF LIF systems are also presented.

  2. Interactions between adrenergic systems, anaesthetic and TRH analogue induced analeptic effects on VBT transmission.

    PubMed

    Clarke, K A; Djouhri, L

    1991-09-01

    Previous behavioural and electrophysiological studies have indicated an antinarcotic action of thyrotropin-releasing hormone (TRH) and its analogues in antagonizing the action of CNS depressant drugs, including baclofen and a variety of anesthetics. While beta-adrenergic receptors are implicated in the level of anaesthesia/arousal, whether the analeptic action of TRH involves adrenergic systems for its expression is uncertain. The object of the present experiments, therefore, was to examine interactions between adrenergic systems and the anti-anaesthetic effects of TRH analogue CG3703. It was found that pretreatment with the beta-block (+/-)propranolol did not abolish or reduce the ability of CG3703 to antagonize urethane-induced depression of VBT transmission. These results suggest therefore, that beta-adrenergic systems are unlikely to be involved in the anti-anaesthetic effect of the tripeptide.

  3. Interaction-induced persistent-current enhancement in frustrated bosonic systems

    NASA Astrophysics Data System (ADS)

    Kerala Varma, Vipin; Sánchez, Ramsés J.

    2015-07-01

    We investigate the effect of next-nearest-neighbor hopping on the zero-temperature Drude weight or superfluidity in mesoscopic one-dimensional systems of (a) a single particle with quasidisorder (Aubry-André model) and (b) hard-core bosons with nearest-neighbor interaction. We show that there is an interaction-induced enhancement of the Drude weight when the next-nearest-neighbor hopping is frustrated for the many-body system. The observed nonmonotonic behavior of the Drude weight occurs because the repulsive interactions first suppress the frustration in the system, leading to a rise in the Drude weight, whereas at much larger interaction strengths the charge density wave fluctuations set in the insulator and the Drude weight drops. The present paper reveals a scenario in which a persistent flow enhancement is plausible in the presence of kinetic frustration and repulsive interactions.

  4. Hantavirus-induced pathogenesis in mice with a humanized immune system.

    PubMed

    Kobak, Lidija; Raftery, Martin J; Voigt, Sebastian; Kühl, Anja A; Kilic, Ergin; Kurth, Andreas; Witkowski, Peter; Hofmann, Jörg; Nitsche, Andreas; Schaade, Lars; Krüger, Detlev H; Schönrich, Günther

    2015-06-01

    Hantaviruses are emerging zoonotic pathogens that can cause severe disease in humans. Clinical observations suggest that human immune components contribute to hantavirus-induced pathology. To address this issue we generated mice with a humanized immune system. Hantavirus infection of these animals resulted in systemic infection associated with weight loss, decreased activity, ruffled fur and inflammatory infiltrates of lung tissue. Intriguingly, after infection, humanized mice harbouring human leukocyte antigen (HLA) class I-restricted human CD8+ T cells started to lose weight earlier (day 10) than HLA class I-negative humanized mice (day 15). Moreover, in these mice the number of human platelets dropped by 77 % whereas the number of murine platelets did not change, illustrating how differences between rodent and human haemato-lymphoid systems may contribute to disease development. To our knowledge this is the first description of a humanized mouse model of hantavirus infection, and our results indicate a role for human immune cells in hantaviral pathogenesis.

  5. Flowing-recirculated water system for inducing spawning phase sea lampreys to spawn in the laboratory

    USGS Publications Warehouse

    Fredricks, Kim T.; Seelye, James G.

    1995-01-01

    We describe a water-recirculating system for inducing spawning of sea lampreys (Petromyzon marinus) held under laboratory conditions. Water temperature in the system was gradually increased to and maintained at 18 ± 2°C, the optimal temperature for spawning. About 10% freshwater was added daily to prevent buildup of waste products. Sea lampreys were provided substrate (approximately 3–6 cm in diameter) to build nests, and a water velocity of 0.2–0.3 m!s was maintained with an electric trolling motor. Sea lampreys held in this system exhibited characteristic spawning behavior. Prolarvae produced from artificial fertilization of gametes developed according to the standard timeline.

  6. Involvement of the dopaminergic system in the central orexin-induced antinociceptive action against colonic distension in conscious rats.

    PubMed

    Okumura, Toshikatsu; Nozu, Tsukasa; Kumei, Shima; Takakusaki, Kaoru; Miyagishi, Saori; Ohhira, Masumi

    2015-09-25

    We have recently demonstrated that orexin acts centrally in the brain to induce antinociceptive action against colonic distension through orexin 1 receptors in conscious rats. Although the dopaminergic system can induce antinociceptive action for somatic pain, the association between changes in the dopaminergic system and visceral pain perception has not been investigated. In the present study, we hypothesized that the dopaminergic system may be involved in visceral nociception, and if so, the dopaminergic system may mediate the orexin-induced visceral antinociception. Visceral sensation was evaluated using the colonic distension-induced abdominal withdrawal reflex (AWR) in conscious rats. Intracisternal injection of D1 (SKF38398) or D2 (quinpirole) dopamine receptor agonist increased the threshold volume of colonic distension-induced AWR in a dose-dependent manner. Pretreatment with either the D1 or D2 dopamine receptor antagonist (SCH23390 or sulpiride, respectively) potently blocked the centrally injected orexin-A-induced antinociceptive action against colonic distension. These results suggest for the first time that dopaminergic signaling via D1 and D2 dopamine receptors in the brain may induce visceral antinociception and that the dopaminergic signaling may be involved in the central orexin-induced antinociceptive action against colonic distension.

  7. [Laser-induced breakdown spectroscopy system for elements analysis in high-temperature and vacuum environment].

    PubMed

    Pan, Cong-Yuan; Du, Xue-Wei; An, Ning; Han, Zhen-Yu; Wang, Sheng-Bo; Wei, Wei; Wang, Qiu-Ping

    2013-12-01

    Laser-induced breakdown spectroscopy (LIBS) is one of the most promising technologies to be applied to metallurgical composition online monitoring in these days. In order to study the spectral characters of LIBS spectrum and to investigate the quantitative analysis method of material composition under vacuum and high temperature environment, a LIBS measurement system was designed and set up which can be used for conducting experiments with high-temperature or molten samples in different vacuum environment. The system consists of a Q-switched Nd : YAG laser used as the light source, lens with different focus lengths used for laser focusing and spectrum signal collecting, a spectrometer used for detecting the signal of LIBS spectrums, and a vacuum system for holding and heating the samples while supplying a vacuum environment. The vacuum was achieved and maintained by a vacuum pump and an electric induction furnace was used for heating the system. The induction coil was integrated to the vacuum system by attaching to a ceramic sealing flange. The system was installed and testified, and the results indicate that the vacuum of the system can reach 1X 10(-4) Pa without heating, while the heating temperature could be about 1 600 degreeC, the system can be used for melting metal samples such as steel and aluminum and get the LIBS spectrum of the samples at the same time. Utilizing this system, LIBS experiments were conducted using standard steel samples under different vacuum or high-temperature conditions. Results of comparison between LIBS spectrums of solid steel samples under different vacuum were achieved, and so are the spectrums of molten and solid steel samples under vacuum environment. Through data processing and theoretical analyzing of these spectrums, the initial results of those experiments are in good agreement with the results that are presently reported, which indicates that the whole system functions well and is available for molten metal LIBS experiment

  8. Defective lipoprotein sorting induces lolA expression through the Rcs stress response phosphorelay system.

    PubMed

    Tao, Kazuyuki; Narita, Shin-Ichiro; Tokuda, Hajime

    2012-07-01

    The Escherichia coli LolA protein is a lipoprotein-specific chaperone that carries lipoproteins from the inner to the outer membrane. A dominant negative LolA mutant, LolA(I93C/F140C), in which both (93)Ile and (140)Phe are replaced by Cys, binds tightly to the lipoprotein-dedicated ABC transporter LolCDE complex on the inner membrane and therefore inhibits the detachment of outer membrane-specific lipoproteins from the inner membrane. We found that the expression of this mutant strongly induced lolA gene transcription. The depletion of the LolA or LolB protein also triggered lolA gene transcription, indicating that the inhibition of outer membrane lipoprotein transport triggers lolA transcription. To elucidate the mechanism, we isolated mutants that are unable to induce lolA transcription using the lacZ gene fused to the lolA promoter as a reporter and found that the Rcs phosphorelay system directly regulates lolA transcription. An outer membrane lipoprotein, RcsF, was essential for this activation, while the coactivator RcsA was dispensable. Taking the observation that an RcsF mutant localized in the inner membrane constitutively activated the Rcs phosphorelay system into consideration, the results shown here strongly suggest that correct lipoprotein sorting to the outer membrane is monitored by RcsF, which plays a key role in the Rcs stress response system.

  9. Bit Error Rate Performance Limitations Due to Raman Amplifier Induced Crosstalk in a WDM Transmission System

    NASA Astrophysics Data System (ADS)

    Tithi, F. H.; Majumder, S. P.

    2017-03-01

    Analysis is carried out for a single span wavelength division multiplexing (WDM) transmission system with distributed Raman amplification to find the effect of amplifier induced crosstalk on the bit error rate (BER) with different system parameters. The results are evaluated in terms of crosstalk power induced in a WDM channel due to Raman amplification, optical signal to crosstalk ratio (OSCR) and BER at any distance for different pump power and number of WDM channels. The results show that the WDM system suffers power penalty due to crosstalk which is significant at higher pump power, higher channel separation and number of WDM channel. It is noticed that at a BER 10-9, the power penalty is 8.7 dB and 10.5 dB for the length of 180 km and number of WDM channel N=32 and 64 respectively when the pump power is 20 mW and is higher at high pump power. Analytical results are validated by simulation.

  10. Laser-induced disruption of systemically administered liposomes for targeted drug delivery

    NASA Astrophysics Data System (ADS)

    Mackanos, Mark A.; Larabi, Malika; Shinde, Rajesh; Simanovskii, Dmitrii M.; Guccione, Samira; Contag, Christopher H.

    2009-07-01

    Liposomal formulations of drugs have been shown to enhance drug efficacy by prolonging circulation time, increasing local concentration and reducing off-target effects. Controlled release from these formulations would increase their utility, and hyperthermia has been explored as a stimulus for targeted delivery of encapsulated drugs. Use of lasers as a thermal source could provide improved control over the release of the drug from the liposomes with minimal collateral tissue damage. Appropriate methods for assessing local release after systemic delivery would aid in testing and development of better formulations. We use in vivo bioluminescence imaging to investigate the spatiotemporal distribution of luciferin, used as a model small molecule, and demonstrate laser-induced release from liposomes in animal models after systemic delivery. These liposomes were tested for luciferin release between 37 and 45 °C in PBS and serum using bioluminescence measurements. In vivo studies were performed on transgenic reporter mice that express luciferase constitutively throughout the body, thus providing a noninvasive readout for controlled release following systemic delivery. An Nd:YLF laser was used (527 nm) to heat tissues and induce rupture of the intravenously delivered liposomes in target tissues. These data demonstrate laser-mediated control of small molecule delivery using thermally sensitive liposomal formulations.

  11. Sensitive electrochemical measurement of hydroxyl radical generation induced by the xanthine-xanthine oxidase system.

    PubMed

    Tatsumi, Hirosuke; Tsuchiya, Yui; Sakamoto, Koichi

    2014-12-15

    A sensitive electrochemical measurement system for hydroxyl radical (OH) was developed using enzyme-catalyzed signal amplification. In the presence of 2,6-xylenol as a trapping agent, glucose as a substrate, and pyrroloquinoline quinone-dependent glucose dehydrogenase (PQQ-GDH) as a catalyst, the amperometric signal of the trapping adduct 2,6-dimethylhydroquinone (DMHQ) produced by the hydroxylation of 2,6-xylenol was able to be amplified and detected sensitively. The limit of detection (signal/noise [S/N]=3) for DMHQ was 1 nM. There was no significant interference from urate and other oxidizable compounds in the reaction mixture at the applied potential of 0V versus Ag/AgCl. This method was employed to observe the OH generation induced by the xanthine-xanthine oxidase (XO) system. The reaction rates of the DMHQ production induced from the xanthine-XO system in the presence and absence of various Fe(III) complexes and proteins were compared. Those with a free coordination site on the Fe atom effectively enhanced the OH generation.

  12. A Low Cost Simulation System to Demonstrate Pilot Induced Oscillation Phenomenon

    NASA Technical Reports Server (NTRS)

    Ali, Syed Firasat

    1997-01-01

    A flight simulation system with graphics and software on Silicon Graphics computer workstations has been installed in the Flight Vehicle Design Laboratory at Tuskegee University. The system has F-15E flight simulation software from NASA Dryden which uses the graphics of SGI flight simulation demos. On the system, thus installed, a study of pilot induced oscillations is planned for future work. Preliminary research is conducted by obtaining two sets of straight level flights with pilot in the loop. In one set of flights no additional delay is used between the stick input and the appearance of airplane response on the computer monitor. In another set of flights, a 500 ms additional delay is used. The flight data is analyzed to find cross correlations between deflections of control surfaces and response of the airplane. The pilot dynamics features depicted from cross correlations of straight level flights are discussed in this report. The correlations presented here will serve as reference material for the corresponding correlations in a future study of pitch attitude tracking tasks involving pilot induced oscillations.

  13. System Voltage Potential-Induced Degradation Mechanisms in PV Modules and Methods for Test: Preprint

    SciTech Connect

    Hacke, P.; Terwilliger, K.; Smith, R.; Glick, S.; Pankow, J.; Kempe, M.; Kurtz, S.; Bennett, I.; Kloos, M.

    2011-07-01

    Over the past decade, degradation and power loss have been observed in PV modules resulting from the stress exerted by system voltage bias. This is due in part to qualification tests and standards that do not adequately evaluate for the durability of modules to the long-term effects of high voltage bias experienced in fielded arrays. High voltage can lead to module degradation by multiple mechanisms. The extent of the voltage bias degradation is linked to the leakage current or coulombs passed from the silicon active layer through the encapsulant and glass to the grounded module frame, which can be experimentally determined; however, competing processes make the effect non-linear and history-dependent. Appropriate testing methods and stress levels are described that demonstrate module durability to system voltage potential-induced degradation (PID) mechanisms. This information, along with outdoor testing that is in progress, is used to estimate the acceleration factors needed to evaluate the durability of modules to system voltage stress. Na-rich precipitates are observed on the cell surface after stressing the module to induce PID in damp heat with negative bias applied to the active layer.

  14. System Voltage Potential-Induced Degradation Mechanisms in PV Modules and Methods for Test

    SciTech Connect

    Hacke, P.; Terwilliger, K.; Smith, R.; Glick, S.; Pankow, J.; Kempe, M.; Kurtz, S.; Bennett, I.; Kloos, M.

    2011-01-01

    Over the past decade, degradation and power loss have been observed in PV modules resulting from the stress exerted by system voltage bias. This is due in part to qualification tests and standards that do not adequately evaluate for the durability of modules to the long-term effects of high voltage bias experienced in fielded arrays. High voltage can lead to module degradation by multiple mechanisms. The extent of the voltage bias degradation is linked to the leakage current or culombs passed from the silicon active layer through the encapsulant and glass to the grounded module frame, which can be experimentally determined; however, competing processes make the effect non-linear and history-dependent. Appropriate testing methods and stress levels are described that demonstrate module durability to system voltage potential-induced degradation (PID) mechanisms. This information, along with outdoor testing that is in progress, is used to estimate the acceleration factors needed to evaluate the durability of modules to system voltage stress. Na-rich precipitates are observed on the cell surface after stressing the module to induce PID in damp heat with negative bias applied to the active layer.

  15. Development of glucose measurement system based on pulsed laser-induced ultrasonic method

    NASA Astrophysics Data System (ADS)

    Ren, Zhong; Wan, Bin; Liu, Guodong; Xiong, Zhihua

    2016-09-01

    In this study, a kind of glucose measurement system based on pulsed-induced ultrasonic technique was established. In this system, the lateral detection mode was used, the Nd: YAG pumped optical parametric oscillator (OPO) pulsed laser was used as the excitation source, the high sensitivity ultrasonic transducer was used as the signal detector to capture the photoacoustic signals of the glucose. In the experiments, the real-time photoacoustic signals of glucose aqueous solutions with different concentrations were captured by ultrasonic transducer and digital oscilloscope. Moreover, the photoacoustic peak-to-peak values were gotten in the wavelength range from 1300nm to 2300nm. The characteristic absorption wavelengths of glucose were determined via the difference spectral method and second derivative method. In addition, the prediction models of predicting glucose concentrations were established via the multivariable linear regression algorithm and the optimal prediction model of corresponding optimal wavelengths. Results showed that the performance of the glucose system based on the pulsed-induced ultrasonic detection method was feasible. Therefore, the measurement scheme and prediction model have some potential value in the fields of non-invasive monitoring the concentration of the glucose gradient, especially in the food safety and biomedical fields.

  16. Shock-induced phase transition in systems of hard spheres with internal degrees of freedom

    NASA Astrophysics Data System (ADS)

    Taniguchi, Shigeru; Mentrelli, Andrea; Zhao, Nanrong; Ruggeri, Tommaso; Sugiyama, Masaru

    2010-06-01

    Shock waves and shock-induced phase transitions are theoretically and numerically studied on the basis of the system of Euler equations with caloric and thermal equations of state for a system of hard spheres with internal degrees of freedom. First, by choosing the unperturbed state (the state before the shock wave) in the liquid phase, the Rankine-Hugoniot conditions are studied and their solutions are classified on the basis of the phase of the perturbed state (the state after the shock wave), being a shock-induced phase transition possible under certain conditions. With this regard, the important role of the internal degrees of freedom is shown explicitly. Second, the admissibility (stability) of shock waves is studied by means of the results obtained by Liu in the theory of hyperbolic systems. It is shown that another type of instability of a shock wave can exist even though the perturbed state is thermodynamically stable. Numerical calculations have been performed in order to confirm the theoretical results in the case of admissible shocks and to obtain the actual evolution of the wave profiles in the case of inadmissible shocks (shock splitting phenomena).

  17. Use of microgravity sensors for quantification of space shuttle orbiter vernier reaction control system induced environments

    NASA Technical Reports Server (NTRS)

    Friend, Robert B.

    1998-01-01

    In the modeling of spacecraft dynamics it is important to accurately characterize the environment in which the vehicle operates, including the environments induced by the vehicle itself. On the Space Shuttle these induced environmental factors include reaction control system plume. Knowledge of these environments is necessary for performance of control systems and loads analyses, estimation of disturbances due to thruster firings, and accurate state vector propagation. During the STS-71 mission, while the Orbiter was performing attitude control for the mated Orbiter/Mir stack, it was noted that the autopilot was limi