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Sample records for heterodimers alter borrelia

  1. TLR1/TLR2 heterodimers play an important role in the recognition of Borrelia spirochetes.

    PubMed

    Oosting, Marije; Ter Hofstede, Hadewych; Sturm, Patrick; Adema, Gosse J; Kullberg, Bart-Jan; van der Meer, Jos W M; Netea, Mihai G; Joosten, Leo A B

    2011-01-01

    After infection with Borrelia species, the risk for developing Lyme disease varies significantly between individuals. Recognition of Borrelia by the immune system is mediated by pattern recognition receptors (PRRs), such as TLRs. While TLR2 is the main recognition receptor for Borrelia spp., little is known about the role of TLR1 and TLR6, which both can form functionally active heterodimers with TLR2. Here we investigated the recognition of Borrelia by both murine and human TLR1 and TLR6. Peritoneal macrophages from TLR1- and TLR6- gene deficient mice were isolated and exposed to Borrelia. Human PBMCs were stimulated with Borrelia with or without specific TLR1 and TLR6 blocking using specific antibodies. Finally, the functional consequences of TLR polymorphisms on Borrelia-induced cytokine production were assessed. Splenocytes isolated from both TLR1-/- and TLR6-/- mice displayed a distorted Th1/Th2 cytokine balance after stimulation with B.burgdorferi, while no differences in pro-inflammatory cytokine production were observed. In contrast, blockade of TLR1 with specific neutralizing antibodies led to decreased cytokine production by human PBMCs after exposure to B.burgdorferi. Blockade of human TLR6 did not lead to suppression of cytokine production. When PBMCs from healthy individuals bearing polymorphisms in TLR1 were exposed to B.burgdorferi, a remarkably decreased in vitro cytokine production was observed in comparison to wild-type controls. TLR6 polymorphisms lead to a minor modified cytokine production. This study indicates a dominant role for TLR1/TLR2 heterodimers in the induction of the early inflammatory response by Borrelia spirochetes in humans. PMID:21998742

  2. Identification of Integrin β Subunit Mutations that Alter Heterodimer Function In SituD⃞

    PubMed Central

    Jannuzi, Alison L.; Bunch, Thomas A.; West, Robert F.; Brower, Danny L.

    2004-01-01

    We conducted a genetic screen for mutations in myospheroid, the gene encoding the Drosophila βPS integrin subunit, and identified point mutants in all of the structural domains of the protein. Surprisingly, we find that mutations in very strongly conserved residues will often allow sufficient integrin function to support the development of adult animals, including mutations in the ADMIDAS site and in a cytoplasmic NPXY motif. Many mutations in the I-like domain reduce integrin expression specifically when βPS is combined with activating αPS2 cytoplasmic mutations, indicating that integrins in the extended conformation are unstable relative to the inactive, bent heterodimers. Interestingly, the screen has identified alleles that show gain-of-function characteristics in cell culture, but have negative effects on animal development or viability. This is illustrated by the allele mysb58; available structural models suggest that the molecular lesion of mysb58, V409>D, should promote the “open” conformation of the β subunit I-like domain. This expectation is supported by the finding that αPS2βPS (V409>D) promotes adhesion and spreading of S2 cells more effectively than does wild-type αPS2βPS, even when βPS is paired with αPS2 containing activating cytoplasmic mutations. Finally, comparisons with the sequence of human β8 suggest that evolution has targeted the “mysb58” residue as a means of affecting integrin activity. PMID:15194810

  3. Ultraviolet-B Radiation Impacts Light-Mediated Turnover of the Photosystem II Reaction Center Heterodimer in Arabidopsis Mutants Altered in Phenolic Metabolism

    PubMed Central

    Booij-James, Isabelle S.; Dube, Shyam K.; Jansen, Marcel A.K.; Edelman, Marvin; Mattoo, Autar K.

    2000-01-01

    Ultraviolet-B (UV-B) radiation can have a negative impact on the growth and development of plants. Plants tolerant to UV-B alleviate these effects using UV-screening pigments that reduce the penetration of UV-B into mesophyll tissue. Little is known about the relative contribution of specific phenolic compounds to the screening capacity of leaves. The D1 and D2 proteins constituting the photosystem (PS) II reaction center heterodimer are targets of UV-B radiation and can be used as an in situ sensor for UV penetration into photosynthetic tissue. Degradation of these proteins occurs under very low fluences of UV-B, and is strongly accelerated in the presence of visible light. Using the D1-D2 degradation assay, we characterized UV-B sensitivity of Arabidopsis mutants (tt4, tt5, and fah1) that are genetically altered in their composition of phenolic compounds. We found that changes in phenol metabolism result in altered rates of PSII reaction center heterodimer degradation under mixtures of photosynthetically active radiation and UV-B. A comparison of D2 degradation kinetics showed increased UV sensitivity of the Landsberg (Landsberg erecta) tt5 mutant relative to the Landsberg tt4 mutant and the Landsberg wild type. Despite a lack of flavonoid accumulation, the tt4 mutant is not particularly UV sensitive. However, the tolerance of this mutant to UV-B may reflect the increased accumulation of sinapate esters that strongly absorb in the UV range, and may thus protect the plant against environmentally relevant UV-B radiation. This sinapate-mediated protection is less obvious for the tt4 mutant of Columbia ecotype, indicating that the relative contribution of particular phenolics to the total screening capacity varies with the genetic background. The role of sinapate esters in UV screening is further substantiated by the results with the fah1 mutant where absence of most of the sinapate esters results in a significantly accelerated degradation of D2 under mixed light

  4. Acylated proteins in Borrelia hermsii, Borrelia parkeri, Borrelia anserina, and Borrelia coriaceae.

    PubMed Central

    Sambri, V; Stefanelli, C; Rossoni, C; La Placa, M; Cevenini, R

    1993-01-01

    Borrelia hermsii, Borrelia parkeri, Borrelia anserina, and Borrelia coriaceae produced several lipoproteins identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography of bacteria grown in [3H]palmitate. Five major acylated proteins were demonstrated by sequential alkaline and acid hydrolysis. High-pressure liquid chromatography of isolated proteins confirmed that covalently bound radioactivity was represented by fatty acids. Images PMID:8285697

  5. Whole-Genome Sequences of Borrelia bissettii Borrelia valaisiana and Borrelia spielmanii

    SciTech Connect

    Schutzer S. E.; Dunn J.; Fraser-Liggett C. M.; Qiu W.-G.; Kraiczy P.; Mongodin E. F.; Luft B. J.; Casjens S. R.

    2012-01-01

    It has been known for decades that human Lyme disease is caused by the three spirochete species Borrelia burgdorferi, Borrelia afzelii, and Borrelia garinii. Recently, Borrelia valaisiana, Borrelia spielmanii, and Borrelia bissettii have been associated with Lyme disease. We report the complete genome sequences of B. valaisiana VS116, B. spielmanii A14S, and B. bissettii DN127.

  6. Interleukin-10 Alters Effector Functions of Multiple Genes Induced by Borrelia burgdorferi in Macrophages To Regulate Lyme Disease Inflammation ▿ †

    PubMed Central

    Gautam, Aarti; Dixit, Saurabh; Philipp, Mario T.; Singh, Shree R.; Morici, Lisa A.; Kaushal, Deepak; Dennis, Vida A.

    2011-01-01

    Interleukin-10 (IL-10) modulates inflammatory responses elicited in vitro and in vivo by Borrelia burgdorferi, the Lyme disease spirochete. How IL-10 modulates these inflammatory responses still remains elusive. We hypothesize that IL-10 inhibits effector functions of multiple genes induced by B. burgdorferi in macrophages to control concomitantly elicited inflammation. Because macrophages are essential in the initiation of inflammation, we used mouse J774 macrophages and live B. burgdorferi spirochetes as the model target cell and stimulant, respectively. First, we employed transcriptome profiling to identify genes that were induced by stimulation of cells with live spirochetes and that were perturbed by addition of IL-10 to spirochete cultures. Spirochetes significantly induced upregulation of 347 genes at both the 4-h and 24-h time points. IL-10 inhibited the expression levels, respectively, of 53 and 65 of the 4-h and 24-h genes, and potentiated, respectively, at 4 h and 24 h, 65 and 50 genes. Prominent among the novel identified IL-10-inhibited genes also validated by quantitative real-time PCR (qRT-PCR) were Toll-like receptor 1 (TLR1), TLR2, IRAK3, TRAF1, IRG1, PTGS2, MMP9, IFI44, IFIT1, and CD40. Proteome analysis using a multiplex enzyme-linked immunosorbent assay (ELISA) revealed the IL-10 modulation/and or potentiation of RANTES/CCL5, macrophage inflammatory protein 2 (MIP-2)/CXCL2, IP-10/CXCL10, MIP-1α/CCL3, granulocyte colony-stimulating factor (G-CSF)/CSF3, CXCL1, CXCL5, CCL2, CCL4, IL-6, tumor necrosis factor alpha (TNF-α), IL-1α, IL-1β, gamma interferon (IFN-γ), and IL-9. Similar results were obtained using sonicated spirochetes or lipoprotein as stimulants. Our data show that IL-10 alters effectors induced by B. burgdorferi in macrophages to control concomitantly elicited inflammatory responses. Moreover, for the first time, this study provides global insight into potential mechanisms used by IL-10 to control Lyme disease inflammation. PMID

  7. Substitution of specific cysteine residues in E1 glycoprotein of classical swine fever virus strain Brescia affects formation of E1-E2 heterodimers and alters virulence in swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    E1, along with E^rns and E2, is one of the three envelope glycoproteins of Classical Swine Fever Virus (CSFV). E1 and E2 are anchored to the virus envelope at their carboxyl termini and E^rns loosely associates with the viral envelope. In infected cells, E2 forms homodimers and heterodimers with E1,...

  8. Relapsing Fever Borreliae in Africa

    PubMed Central

    Elbir, Haitham; Raoult, Didier; Drancourt, Michel

    2013-01-01

    The study of relapsing fever borreliae in Africa has long suffered from the use of non-specific laboratory tools for the direct detection of these spirochetes in clinical and vector specimens. Accordingly, Borrelia hispanica, Borrelia crocidurae, Borrelia duttonii, and Borrelia recurrentis have traditionally been distinguished on the basis of geography and vector and the unproven hypothesis that each species was exclusive to one vector. The recent sequencing of three relapsing fever Borrelia genomes in our laboratory prompted the development of more specific tools and a reappraisal of the epidemiology in Africa. Five additional potential species still need to be cultured from clinical and vector sources in East Africa to further assess their uniqueness. Here, we review the molecular evidence of relapsing fever borreliae in hosts and ectoparasites in Africa and explore the diversity, geographical distribution, and vector association of these pathogens for Africans and travelers to Africa. PMID:23926141

  9. Coexistence of Phases in a Protein Heterodimer

    PubMed Central

    Krokhotin, Andrey; Liwo, Adam; Niemi, Antti J.; Scheraga, Harold A.

    2012-01-01

    A heterodimer consisting of two or more different kinds of proteins can display an enormous number of distinct molecular architectures. The conformational entropy is an essential ingredient in the Helmholtz free energy and, consequently, these heterodimers can have a very complex phase structure. Here, it is proposed that there is a state of proteins, in which the different components of a heterodimer exist in different phases. For this purpose, the structures in the protein data bank (PDB) have been analyzed, with radius of gyration as the order parameter. Two major classes of heterodimers with their protein components coexisting in different phases have been identified. An example is the PDB structure 3DXC. This is a transcriptionally active dimer. One of the components is an isoform of the intra-cellular domain of the Alzheimer-disease related amyloid precursor protein (AICD), and the other is a nuclear multidomain adaptor protein in the Fe65 family. It is concluded from the radius of gyration that neither of the two components in this dimer is in its own collapsed phase, corresponding to a biologically active protein. The UNRES energy function has been utilized to confirm that, if the two components are separated from each other, each of them collapses. The results presented in this work show that heterodimers whose protein components coexist in different phases, can have intriguing physical properties with potentially important biological consequences. PMID:22830730

  10. [Diseases produced by Borrelia].

    PubMed

    Escudero-Nieto, Raquel; Guerrero-Espejo, Antonio

    2005-04-01

    Lyme borreliosis, caused by Borrelia burgdorferi sensu lato, is a multi-organ infection with dermatological, rheumatological, neurological, and cardiac manifestations. The main characteristic is a skin lesion, named erythema migrans. Relapsing fever, caused by numerous species of Borrelia, is characterized by a periodic cycle of acute and afebrile episodes. The serological diagnosis of these infections has limited value in sensitivity, specificity and predictive values. Lyme borreliosis is usually diagnosed by recognition of a characteristic clinical picture with serological confirmation, and the diagnosis of relapsing fever relies on direct observation of spirochetes in peripherical blood. The elected treatment is almost always tetracycline for the young or for adults but not for pregnant women, although betalactamic (such as penicillin or 3rd generation cephalosporin for the central nervous system) or macrolides are indicated in several situations. The prognosis, with adequate treatment, is good. In the majority of Spanish regions, due to the low incidence of these diseases, the prophylactic antimicrobial treatment after a tick bite is not indicated. PMID:15826549

  11. Intramolecular Singlet Fission in Oligoacene Heterodimers.

    PubMed

    Sanders, Samuel N; Kumarasamy, Elango; Pun, Andrew B; Steigerwald, Michael L; Sfeir, Matthew Y; Campos, Luis M

    2016-03-01

    We investigate singlet fission (SF) in heterodimers comprising a pentacene unit covalently bonded to another acene as we systematically vary the singlet and triplet pair energies. We find that these energies control the SF process, where dimers undergo SF provided that the resulting triplet pair energy is similar or lower in energy than the singlet state. In these systems the singlet energy is determined by the lower-energy chromophore, and the rate of SF is found to be relatively independent of the driving force. However, triplet pair recombination in these heterodimers follows the energy gap law. The ability to tune the energies of these materials provides a key strategy to study and design new SF materials-an important process for third-generation photovoltaics. PMID:26836223

  12. Molecular Typing of Borrelia burgdorferi

    PubMed Central

    Wang, Guiqing; Liveris, Dionysios; Mukherjee, Priyanka; Jungnick, Sabrina; Margos, Gabriele; Schwartz, Ira

    2015-01-01

    Borrelia burgdorferi sensu lato is a group of spirochetes belonging to the genus Borrelia in the family of Spirochaetaceae. The spirochete is transmitted between reservoirs and hosts by ticks of the family Ixodidae. Infection with B. burgdorferi in humans causes Lyme disease or Lyme borreliosis. Currently, 20 Lyme disease-associated Borrelia species and more than 20 relapsing fever-associated Borrelia species have been described. Identification and differentiation of different Borrelia species and strains is largely dependent on analyses of their genetic characteristics. A variety of molecular techniques have been described for Borrelia isolate speciation, molecular epidemiology, and pathogenicity studies. In this unit, we focus on three basic protocols, PCR-RFLP-based typing of the rrs-rrlA and rrfA-rrlB ribosomal spacer, ospC typing, and MLST. These protocols can be employed alone or in combination for characterization of B. burgdorferi isolates or directly on uncultivated organisms in ticks, mammalian host reservoirs, and human clinical specimens. PMID:25082003

  13. Class A GPCR heterodimers: evidence from binding studies.

    PubMed

    Birdsall, Nigel J M

    2010-11-01

    There is a large body of experimental evidence that is compatible with the presence of heterodimers of the major A subclass of G protein-coupled receptors (GPCRs) and suggests that these heterodimers might have different functional properties from those of the monomers (or homodimers) of the individual receptors that engage in heterodimer formation. The question is whether there are allosteric interactions across the receptor-receptor interface of a heterodimer that modulate the binding properties of the heterodimer components and thereby change their pharmacology. In this review, I examine published experimental evidence from radioligand binding studies in the context of different models of allosterism and discuss a number of apparently discrepant results. The analysis suggests that more experimental data are required if equal, two-way, crossreceptor interactions within a GPCR heterodimer, at the level of binding, are to be unequivocally demonstrated. PMID:20870299

  14. Borrelia burgdorferi Infections in the United States

    PubMed Central

    Heymann, Warren R.

    2012-01-01

    It is becoming increasingly evident that the clinical presentation of infection with Borrelia burgdorferi varies greatly between different parts of the world. A growing number of European and Asian isolates of Lyme borreliae, differing from the American strain of Borrelia burgdorferi, have been identified in several different disorders. In light of the increasing number of reports describing an association between various cutaneous disorders and infection with Borrelia burgdorferi and the controversy that still remains over where Borrelia burgdorferi is truly pathogenic in these diseases, this review of the literature assesses the significance of these reports in substantiating these hypotheses, as such associations are important both diagnostically and therapeutically. PMID:22916311

  15. Genetics of Borrelia burgdorferi

    PubMed Central

    Brisson, Dustin; Drecktrah, Dan; Eggers, Christian H.; Samuels, D. Scott

    2013-01-01

    The spirochetes in the Borrelia burgdorferi sensu lato genospecies group cycle in nature between tick vectors and vertebrate hosts. The current assemblage of B. burgdorferi sensu lato, of which three species cause Lyme disease in humans, originated from a rapid species radiation that occurred near the origin of the clade. All of these species share a unique genome structure that is highly segmented and predominantly composed of linear replicons. One of the circular plasmids is a prophage that exists as several isoforms in each cell and can be transduced to other cells, likely contributing to an otherwise relatively anemic level of horizontal gene transfer, which nevertheless appears to be adequate to permit strong natural selection and adaptation in populations of B. burgdorferi. Although the molecular genetic toolbox is meager, several antibiotic-resistant mutants have been isolated, and the resistance alleles, as well as some exogenous genes, have been fashioned into markers to dissect gene function. Genetic studies have probed the role of the outer membrane lipoprotein OspC, which is maintained in nature by multiple niche polymorphisms and negative frequency-dependent selection. One of the most intriguing genetic systems in B. burgdorferi is vls recombination, which generates antigenic variation during infection of mammalian hosts. PMID:22974303

  16. A Fluorogenic Red Fluorescent Protein Heterodimer

    PubMed Central

    Alford, Spencer C.; Abdelfattah, Ahmed S.; Ding, Yidan; Campbell, Robert E.

    2012-01-01

    SUMMARY The expanding repertoire of genetically encoded biosensors constructed from variants of Aequorea victoria green fluorescent protein (GFP) enable the imaging of a variety of intracellular biochemical processes. To facilitate the imaging of multiple biosensors in a single cell, we undertook the development of a dimerization-dependent red fluorescent protein (ddRFP) that provides an alternative strategy for biosensor construction. An extensive process of rational engineering and directed protein evolution led to the discovery of a ddRFP with a Kd of 33 μM and a 10-fold increase in fluorescence upon heterodimer formation. We demonstrate that the dimerization-dependent fluorescence of ddRFP can be used for detection of a protein-protein interaction in vitro, imaging of the reversible Ca2+-dependent association of calmodulin and M13 in live cells, and imaging of caspase-3 activity during apoptosis. PMID:22444590

  17. Recombinant constructs of Borrelia burgdorferi

    DOEpatents

    Dattwyler, Raymond J.; Gomes-Solecki, Maria J. C.; Luft, Benjamin J.; Dunn, John J.

    2007-02-20

    Novel chimeric nucleic acids, encoding chimeric Borrelia proteins comprising OspC or an antigenic fragment thereof and OspA or an antigenic fragment thereof, are disclosed. Chimeric proteins encoded by the nucleic acid sequences are also disclosed. The chimeric proteins are useful as vaccine immunogens against Lyme borreliosis, as well as for immunodiagnostic reagents.

  18. Borrelia hispanica Relapsing Fever, Morocco

    PubMed Central

    Sarih, M’hammed; Garnier, Martine; Boudebouch, Najma; Bouattour, Ali; Rihani, Abdelaziz; Hassar, Mohammed; Gern, Lise; Postic, Danièle

    2009-01-01

    We found that 20.5% of patients with an unexplained fever in northwestern Morocco had tick-borne relapsing fever. Molecular detection specific for the 16S rRNA gene identified Borrelia hispanica. The noncoding intergenic spacer sequence domain showed high sensitivity and good resolution for this species. PMID:19861058

  19. Borrelia hispanica relapsing fever, Morocco.

    PubMed

    Sarih, M'hammed; Garnier, Martine; Boudebouch, Najma; Bouattour, Ali; Rihani, Abdelaziz; Hassar, Mohammed; Gern, Lise; Postic, Danièle; Cornet, Muriel

    2009-10-01

    We found that 20.5% of patients with an unexplained fever in northwestern Morocco had tick-borne relapsing fever. Molecular detection specific for the 16S rRNA gene identified Borrelia hispanica. The noncoding intergenic spacer sequence domain showed high sensitivity and good resolution for this species. PMID:19861058

  20. Comparison of Growth of Borrelia afzelii, Borrelia garinii, and Borrelia burgdorferi Sensu Stricto at Five Different Temperatures

    PubMed Central

    Veinović, Gorana; Ružić-Sabljić, Eva; Strle, Franc; Cerar, Tjaša

    2016-01-01

    Lyme borreliosis is caused by the spirochete Borrelia burgdorferi sensu lato, a fastidious bacterium that replicates slowly and requires special conditions to grow in the laboratory. Borrelia isolation from clinical material is a golden standard for microbiological diagnosis of borrelial infection. Important factors that affect in vitro borrelia growth are temperature of incubation and number of borrelia cells in the sample. The aim of the study was to assess the influence of temperature on borrelia growth and survival by evaluation and comparison of growth of 31 different borrelia strains at five different temperatures and to determine the influence of different inoculums on borrelia growth at different temperatures. Borreliae were cultured in the MKP medium; the initial and final number of spirochetes was determined by dark field microscopy using Neubauer counting chamber. The growth of borrelia was defined as final number of cells/mL after three days of incubation. For all three Borrelia species, the best growth was found at 33°C, followed by 37, 28, and 23°C, while no growth was detected at 4°C (P<0.05). The growth of B. afzelii species was weaker in comparison to the other two species at 23, 28, 33 and 37°C (P<0.05), respectively. There was no statistically significant difference between the growth of B. garinii and B. burgdorferi sensu stricto at 28, 33, and 37°C (P>0.05), respectively. Inoculum had statistically significant influence on growth of all three Borrelia species at all tested temperatures except at 4°C. PMID:27310556

  1. Comparison of Growth of Borrelia afzelii, Borrelia garinii, and Borrelia burgdorferi Sensu Stricto at Five Different Temperatures.

    PubMed

    Veinović, Gorana; Ružić-Sabljić, Eva; Strle, Franc; Cerar, Tjaša

    2016-01-01

    Lyme borreliosis is caused by the spirochete Borrelia burgdorferi sensu lato, a fastidious bacterium that replicates slowly and requires special conditions to grow in the laboratory. Borrelia isolation from clinical material is a golden standard for microbiological diagnosis of borrelial infection. Important factors that affect in vitro borrelia growth are temperature of incubation and number of borrelia cells in the sample. The aim of the study was to assess the influence of temperature on borrelia growth and survival by evaluation and comparison of growth of 31 different borrelia strains at five different temperatures and to determine the influence of different inoculums on borrelia growth at different temperatures. Borreliae were cultured in the MKP medium; the initial and final number of spirochetes was determined by dark field microscopy using Neubauer counting chamber. The growth of borrelia was defined as final number of cells/mL after three days of incubation. For all three Borrelia species, the best growth was found at 33°C, followed by 37, 28, and 23°C, while no growth was detected at 4°C (P<0.05). The growth of B. afzelii species was weaker in comparison to the other two species at 23, 28, 33 and 37°C (P<0.05), respectively. There was no statistically significant difference between the growth of B. garinii and B. burgdorferi sensu stricto at 28, 33, and 37°C (P>0.05), respectively. Inoculum had statistically significant influence on growth of all three Borrelia species at all tested temperatures except at 4°C. PMID:27310556

  2. Small Heterodimer Partner and Innate Immune Regulation

    PubMed Central

    Jin, Hyo Sun

    2016-01-01

    The nuclear receptor superfamily consists of the steroid and non-steroid hormone receptors and the orphan nuclear receptors. Small heterodimer partner (SHP) is an orphan family nuclear receptor that plays an essential role in the regulation of glucose and cholesterol metabolism. Recent studies reported a previously unidentified role for SHP in the regulation of innate immunity and inflammation. The innate immune system has a critical function in the initial response against a variety of microbial and danger signals. Activation of the innate immune response results in the induction of inflammatory cytokines and chemokines to promote anti-microbial effects. An excessive or uncontrolled inflammatory response is potentially harmful to the host, and can cause tissue damage or pathological threat. Therefore, the innate immune response should be tightly regulated to enhance host defense while preventing unwanted immune pathologic responses. In this review, we discuss recent studies showing that SHP is involved in the negative regulation of toll-like receptor-induced and NLRP3 (NACHT, LRR and PYD domains-containing protein 3)-mediated inflammatory responses in innate immune cells. Understanding the function of SHP in innate immune cells will allow us to prevent or modulate acute and chronic inflammation processes in cases where dysregulated innate immune activation results in damage to normal tissues. PMID:26754583

  3. Small Heterodimer Partner and Innate Immune Regulation.

    PubMed

    Yuk, Jae Min; Jin, Hyo Sun; Jo, Eun Kyeong

    2016-03-01

    The nuclear receptor superfamily consists of the steroid and non-steroid hormone receptors and the orphan nuclear receptors. Small heterodimer partner (SHP) is an orphan family nuclear receptor that plays an essential role in the regulation of glucose and cholesterol metabolism. Recent studies reported a previously unidentified role for SHP in the regulation of innate immunity and inflammation. The innate immune system has a critical function in the initial response against a variety of microbial and danger signals. Activation of the innate immune response results in the induction of inflammatory cytokines and chemokines to promote anti-microbial effects. An excessive or uncontrolled inflammatory response is potentially harmful to the host, and can cause tissue damage or pathological threat. Therefore, the innate immune response should be tightly regulated to enhance host defense while preventing unwanted immune pathologic responses. In this review, we discuss recent studies showing that SHP is involved in the negative regulation of toll-like receptor-induced and NLRP3 (NACHT, LRR and PYD domains-containing protein 3)-mediated inflammatory responses in innate immune cells. Understanding the function of SHP in innate immune cells will allow us to prevent or modulate acute and chronic inflammation processes in cases where dysregulated innate immune activation results in damage to normal tissues. PMID:26754583

  4. Design and Applications of Bispecific Heterodimers: Molecular Imaging and beyond

    PubMed Central

    2015-01-01

    Ligand-based molecular imaging probes have been designed with high affinity and specificity for monitoring biological process and responses. Single-target recognition by traditional probes can limit their applicability for disease detection and therapy because synergistic action between disease mediators and different receptors is often involved in disease progression. Consequently, probes that can recognize multiple targets should demonstrate higher targeting efficacy and specificity than their monospecific peers. This concept has been validated by multiple bispecific heterodimer-based imaging probes that have demonstrated promising results in several animal models. This review summarizes the design strategies for bispecific peptide- and antibody-based heterodimers and their applications in molecular targeting and imaging. The design and application of bispecific heterodimer-conjugated nanomaterials are also discussed. PMID:24738564

  5. Structural mechanism for signal transduction in RXR nuclear receptor heterodimers

    PubMed Central

    Kojetin, Douglas J.; Matta-Camacho, Edna; Hughes, Travis S.; Srinivasan, Sathish; Nwachukwu, Jerome C.; Cavett, Valerie; Nowak, Jason; Chalmers, Michael J.; Marciano, David P.; Kamenecka, Theodore M.; Shulman, Andrew I.; Rance, Mark; Griffin, Patrick R.; Bruning, John B.; Nettles, Kendall W.

    2015-01-01

    A subset of nuclear receptors (NRs) function as obligate heterodimers with retinoid X receptor (RXR), allowing integration of ligand-dependent signals across the dimer interface via an unknown structural mechanism. Using nuclear magnetic resonance (NMR) spectroscopy, x-ray crystallography and hydrogen/deuterium exchange (HDX) mass spectrometry, here we show an allosteric mechanism through which RXR co-operates with a permissive dimer partner, peroxisome proliferator-activated receptor (PPAR)-γ, while rendered generally unresponsive by a non-permissive dimer partner, thyroid hormone (TR) receptor. Amino acid residues that mediate this allosteric mechanism comprise an evolutionarily conserved network discovered by statistical coupling analysis (SCA). This SCA network acts as a signalling rheostat to integrate signals between dimer partners, ligands and coregulator-binding sites, thereby affecting signal transmission in RXR heterodimers. These findings define rules guiding how NRs integrate two ligand-dependent signalling pathways into RXR heterodimer-specific responses. PMID:26289479

  6. Multilocus sequence analysis of Borrelia bissettii strains from North America reveals a new Borrelia species, Borrelia kurtenbachii

    PubMed Central

    Margos, Gabriele; Hojgaard, Andrias; Lane, Robert S.; Cornet, Muriel; Fingerle, Volker; Rudenko, Nataliia; Ogden, Nicholas; Aanensen, David M.; Fish, Durland; Piesman, Joseph

    2010-01-01

    Using multilocus sequence analyses (MLSA), we investigated the phylogenetic relationship of spirochaete strains from North America previously assigned to the genospecies Borrelia bissettii. We amplified internal fragments of 8 housekeeping genes (clpA, clpX, nifS, pepX, pyrG, recG, rplB, and uvrA) located on the main linear chromosome by polymerase chain reaction. Phylogenetic analysis of concatenated sequences of the 8 loci showed that the B. bissettii clade consisted of 4 closely related clusters which included strains from California (including the type strain DN127-Cl9-2/p7) and Colorado that were isolated from Ixodes pacificus, I. spinipalpis, or infected reservoir hosts. Several strains isolated from I. scapularis clustered distantly from B. bissettii. Genetic distance analyses confirmed that these strains are more distant to B. bissettii than they are to B. carolinensis, a recently described Borrelia species, which suggests that they constitute a new Borrelia genospecies. We propose that it be named Borrelia kurtenbachii sp. nov. in honour of the late Klaus Kurtenbach. The data suggest that ecological differences between B. bissettii and the new Borrelia genospecies reflect different transmission cycles. In view of these findings, the distinct vertebrate host-tick vector associations and the distributions of B. bissettii and B. kurtenbachii require further investigation. PMID:21157575

  7. Fourier transform infrared spectroscopy of DNA from Borrelia burgdorferi sensu lato and Ixodes ricinus ticks.

    PubMed

    Muntean, Cristina M; Stefan, Razvan; Bindea, Maria; Cozma, Vasile

    2013-06-01

    In this work we present a method for detection of motile and immotile Borrelia burgdorferi genomic DNA, in relation with infectious and noninfectious spirochetes. An FT-IR study of DNA isolated from B. burgdorferi sensu lato strains and from positive and negative Ixodes ricinus ticks, respectively, is reported. Motile bacterial cells from the species B. burgdorferi sensu stricto, Borrelia garinii and Borrelia afzelii were of interest. Also, FT-IR absorbance spectra of DNA from immotile spirochetes of B. burgdorferi sensu stricto, in the absence and presence of different antibiotics (doxycycline, erythromycin, gentamicin, penicillin V or phenoxymethylpenicillin, tetracycline, respectively) were investigated. FT-IR spectra, providing a high molecular structural information, have been analyzed in the wavenumber range 400-1800 cm(-1). FT-IR signatures, spectroscopic band assignments and structural interpretations of these DNAs are reported. Spectral differences between FT-IR absorbances of DNAs from motile bacterial cells and immotile spirochetes, respectively, have been found. Particularly, alterations of the sugar-phosphate B-form chain in the case of DNA from Borrelia immotile cells, as compared with DNA from B. burgdorferi sensu lato motile cells have been observed. Based on this work, specific B. burgdorferi sensu lato and I. ricinus DNA-ligand interactions, respectively, might be further investigated using Fourier transform infrared spectroscopy. PMID:23563637

  8. Fourier transform infrared spectroscopy of DNA from Borrelia burgdorferi sensu lato and Ixodes ricinus ticks

    NASA Astrophysics Data System (ADS)

    Muntean, Cristina M.; Stefan, Razvan; Bindea, Maria; Cozma, Vasile

    2013-06-01

    In this work we present a method for detection of motile and immotile Borrelia burgdorferi genomic DNA, in relation with infectious and noninfectious spirochetes. An FT-IR study of DNA isolated from B. burgdorferi sensu lato strains and from positive and negative Ixodes ricinus ticks, respectively, is reported. Motile bacterial cells from the species B. burgdorferi sensu stricto, Borrelia garinii and Borrelia afzelii were of interest. Also, FT-IR absorbance spectra of DNA from immotile spirochetes of B. burgdorferi sensu stricto, in the absence and presence of different antibiotics (doxycycline, erythromycin, gentamicin, penicillin V or phenoxymethylpenicillin, tetracycline, respectively) were investigated. FT-IR spectra, providing a high molecular structural information, have been analyzed in the wavenumber range 400-1800 cm-1. FT-IR signatures, spectroscopic band assignments and structural interpretations of these DNAs are reported. Spectral differences between FT-IR absorbances of DNAs from motile bacterial cells and immotile spirochetes, respectively, have been found. Particularly, alterations of the sugar-phosphate B-form chain in the case of DNA from Borrelia immotile cells, as compared with DNA from B. burgdorferi sensu lato motile cells have been observed. Based on this work, specific B. burgdorferi sensu lato and I. ricinus DNA-ligand interactions, respectively, might be further investigated using Fourier transform infrared spectroscopy.

  9. Borrelia burgdorferi tissue morphologies and imaging methodologies.

    PubMed

    MacDonald, A B

    2013-08-01

    This manuscript offers an image presentation of diverse forms of Borrelia burgdorferi spirochetes which are not spiral or corkscrew shaped. Explanations are offered to justify the legitimacy of tissue forms of Borrelia which may confuse the inexperienced microscopic examiner and which may lead to the misdiagnosis of non-spiral forms as artifacts. Images from the author's personal collection of Borrelia burgdorferi images and a few select images of Borrelia burgdorferi from the peer-reviewed published literature are presented. A commentary justifying each of the image profiles and a survey of the imaging modalities utilized provides the reader with a frame of reference. Regularly spiraled Borrelia are rarely seen in solid tissues. A variety of straightened, undulating, and clipped-off profiles are demonstrated, and the structural basis for each image is explained. Tissue examination is a diagnostic tool and a quality control for judging the eradication or the persistence of borreliosis following attempts to eradicate the infection with antibiotic therapy. The presence or absence of chronic Lyme borreliosis may be objectively adjudicated by tissue examinations which demonstrate or which fail to show pathogenic microbes in patients who have received a full course of antibiotics. PMID:23479042

  10. Whole-Genome Sequences of Two Borrelia afzelii and Two Borrelia garinii Lyme Disease Agent Isolates

    PubMed Central

    Casjens, Sherwood R.; Mongodin, Emmanuel F.; Qiu, Wei-Gang; Dunn, John J.; Luft, Benjamin J.; Fraser-Liggett, Claire M.; Schutzer, Steve E.

    2011-01-01

    Human Lyme disease is commonly caused by several species of spirochetes in the Borrelia genus. In Eurasia these species are largely Borrelia afzelii, B. garinii, B. burgdorferi, and B. bavariensis sp. nov. Whole-genome sequencing is an excellent tool for investigating and understanding the influence of bacterial diversity on the pathogenesis and etiology of Lyme disease. We report here the whole-genome sequences of four isolates from two of the Borrelia species that cause human Lyme disease, B. afzelii isolates ACA-1 and PKo and B. garinii isolates PBr and Far04. PMID:22123755

  11. Whole-Genome Sequences of Two Borrelia afzelii and Two Borrelia garinii Lyme Disease Agent Isolates

    SciTech Connect

    Casjens, S.R.; Dunn, J.; Mongodin, E. F.; Qiu, W.-G.; Luft, B. J.; Fraser-Liggett, C. M.; Schutzer, S. E.

    2011-12-01

    Human Lyme disease is commonly caused by several species of spirochetes in the Borrelia genus. In Eurasia these species are largely Borrelia afzelii, B. garinii, B. burgdorferi, and B. bavariensis sp. nov. Whole-genome sequencing is an excellent tool for investigating and understanding the influence of bacterial diversity on the pathogenesis and etiology of Lyme disease. We report here the whole-genome sequences of four isolates from two of the Borrelia species that cause human Lyme disease, B. afzelii isolates ACA-1 and PKo and B. garinii isolates PBr and Far04.

  12. Quantifying the parameters of Prusiner's heterodimer model for prion replication

    NASA Astrophysics Data System (ADS)

    Li, Z. R.; Liu, G. R.; Mi, D.

    2005-02-01

    A novel approach for the determination of parameters in prion replication kinetics is developed based on Prusiner's heterodimer model. It is proposed to employ a simple 2D HP lattice model and a two-state transition theory to determine kinetic parameters that play the key role in the prion replication process. The simulation results reveal the most important facts observed in the prion diseases, including the long incubation time, rapid death following symptom manifestation, the effect of inoculation size, different mechanisms of the familial and infectious prion diseases, etc. Extensive simulation with various thermodynamic parameters shows that the Prusiner's heterodimer model is applicable, and the putative protein X plays a critical role in replication of the prion disease.

  13. Hemolytic activity of Borrelia burgdorferi.

    PubMed Central

    Williams, L R; Austin, F E

    1992-01-01

    Zones of beta-hemolysis occurred around colonies of Borrelia burgdorferi grown on Barbour-Stoenner-Kelly medium containing agarose and horse blood. Blood plates were inoculated with either the infective strain Sh-2-82 or noninfective strain B-31 in an overlay and incubated in a candle jar. Both strains of B. burgdorferi displayed beta-hemolysis after 1 to 2 weeks of incubation. The hemolytic activity diffused out from the borrelial colonies, eventually resulting in lysis of the entire blood plate. Hemolysis was most pronounced with horse blood and was less intense with bovine, sheep, and rabbit blood. Hemolysis was enhanced by hot-cold incubation, which is typical of phospholipase-like activities in other bacteria. Further characterization of the borrelial hemolysin by using a spectrophotometric assay revealed its presence in the supernatant fluids of stationary-phase cultures. Detection of the borrelial hemolytic activity was dependent on activation of the hemolysin by the reducing agent cysteine. This study provides the first evidence of hemolytic activity associated with B. burgdorferi. Images PMID:1639493

  14. Resonance coupling in plasmonic nanomatryoshka homo- and heterodimers

    NASA Astrophysics Data System (ADS)

    Ahmadivand, Arash; Sinha, Raju; Pala, Nezih

    2016-06-01

    Here, we examine the electromagnetic (EM) energy coupling and hybridization of plasmon resonances between closely spaced concentric nanoshells known as "nanomatryoshka" (NM) units in symmetric and antisymmetric compositions using the Finite Difference Time Domain (FDTD) analysis. Utilizing plasmon hybridization model, we calculated the energy level diagrams and verified that, in the symmetric dimer (in-phase mode in a homodimer), plasmonic bonding modes are dominant and tunable within the considered bandwidth. In contrast, in the antisymmetric dimer (out-of-phase mode in a heterodimer), due to the lack of the geometrical symmetry, new antibonding modes appear in the extinction profile, and this condition gives rise to repeal of dipolar field coupling. We also studied the extinction spectra and positions of the antibonding and bonding modes excited due to the energy coupling between silver and gold NM units in a heterodimer structure. Our analysis suggest abnormal shifts in the higher energy modes. We propose a method to analyze the behavior of multilayer concentric nanoshell particles in an antisymmetric orientation employing full dielectric function calculations and the Drude model based on interband transitions in metallic components. This study provides a method to predict the behavior of the higher energy plasmon resonant modes in entirely antisymmetric structures such as compositional heterodimers.

  15. Small Heterodimer Partner (NR0B2) Coordinates Nutrient Signaling and the Circadian Clock in Mice.

    PubMed

    Wu, Nan; Kim, Kang Ho; Zhou, Ying; Lee, Jae Man; Kettner, Nicole M; Mamrosh, Jennifer L; Choi, Sungwoo; Fu, Loning; Moore, David D

    2016-09-01

    Circadian rhythm regulates multiple metabolic processes and in turn is readily entrained by feeding-fasting cycles. However, the molecular mechanisms by which the peripheral clock senses nutrition availability remain largely unknown. Bile acids are under circadian control and also increase postprandially, serving as regulators of the fed state in the liver. Here, we show that nuclear receptor Small Heterodimer Partner (SHP), a regulator of bile acid metabolism, impacts the endogenous peripheral clock by directly regulating Bmal1. Bmal1-dependent gene expression is altered in Shp knockout mice, and liver clock adaptation is delayed in Shp knockout mice upon restricted feeding. These results identify SHP as a potential mediator connecting nutrient signaling with the circadian clock. PMID:27427832

  16. The dynamic proteome of Lyme disease Borrelia.

    PubMed

    Norris, Steven J

    2006-01-01

    The proteome of the spirochete bacterium Borrelia burgdorferi, the tick-borne agent of Lyme disease, has been characterized by two different approaches using mass spectrometry, providing a launching point for future studies on the dramatic changes in protein expression that occur during transmission of the bacterium between ticks and mammals. PMID:16563176

  17. Borrelia recurrentis in Head Lice, Ethiopia

    PubMed Central

    Boutellis, Amina; Mediannikov, Oleg; Bilcha, Kassahun Desalegn; Ali, Jemal; Campelo, Dayana; Barker, Stephen C.

    2013-01-01

    Since the 1800s, the only known vector of Borrelia recurrentis has been the body louse. In 2011, we found B. recurrentis DNA in 23% of head lice from patients with louse-borne relapsing fever in Ethiopia. Whether head lice can transmit these bacteria from one person to another remains to be determined. PMID:23648147

  18. Blood-Borne Candidatus Borrelia algerica in a Patient with Prolonged Fever in Oran, Algeria.

    PubMed

    Fotso Fotso, Aurélien; Angelakis, Emmanouil; Mouffok, Nadjet; Drancourt, Michel; Raoult, Didier

    2015-11-01

    To improve the knowledge base of Borrelia in north Africa, we tested 257 blood samples collected from febrile patients in Oran, Algeria, between January and December 2012 for Borrelia species using flagellin gene polymerase chain reaction sequencing. A sequence indicative of a new Borrelia sp. named Candidatus Borrelia algerica was detected in one blood sample. Further multispacer sequence typing indicated this Borrelia sp. had 97% similarity with Borrelia crocidurae, Borrelia duttonii, and Borrelia recurrentis. In silico comparison of Candidatus B. algerica spacer sequences with those of Borrelia hispanica and Borrelia garinii revealed 94% and 89% similarity, respectively. Candidatus B. algerica is a new relapsing fever Borrelia sp. detected in Oran. Further studies may help predict its epidemiological importance. PMID:26416117

  19. Virulence of recurrent infestations with Borrelia-infected ticks in a Borrelia-amplifying bird

    PubMed Central

    Heylen, Dieter J. A.; Müller, Wendt; Vermeulen, Anke; Sprong, Hein; Matthysen, Erik

    2015-01-01

    Lyme disease cases caused by Borrelia burgdorferi s.l. bacteria is increasing steadily in Europe, in part due to the expansion of the vector, Ixodes ricinus. Wild reservoir hosts are typically recurrently infested. Understanding the impact of these cumulative parasite exposures on the host’s health is, therefore, central to predict the distribution of tick populations and their pathogens. Here, we have experimentally investigated the symptoms of disease caused by recurrent infestations in a common songbird (Parus major). Birds were exposed three times in succession to ticks collected in a Borrelia endemic area. Health and immune measures were analyzed in order to investigate changes in response to tick infestation and Borrelia infection rate. Nitric oxide levels increased with the Borrelia infection rate, but this effect was increasingly counteracted by mounting tick infestation rates. Tick infestations equally reduced haematocrit during each cycle. But birds overcompensated in their response to tick feeding, having higher haematocrit values during tick-free periods depending on the number of ticks they had been previously exposed to. Body condition showed a similar overshooting response in function of the severity of the Borrelia infection. The observed overcompensation increases the bird’s energetic needs, which may result in an increase in transmission events. PMID:26553505

  20. Virulence of recurrent infestations with Borrelia-infected ticks in a Borrelia-amplifying bird

    NASA Astrophysics Data System (ADS)

    Heylen, Dieter J. A.; Müller, Wendt; Vermeulen, Anke; Sprong, Hein; Matthysen, Erik

    2015-11-01

    Lyme disease cases caused by Borrelia burgdorferi s.l. bacteria is increasing steadily in Europe, in part due to the expansion of the vector, Ixodes ricinus. Wild reservoir hosts are typically recurrently infested. Understanding the impact of these cumulative parasite exposures on the host’s health is, therefore, central to predict the distribution of tick populations and their pathogens. Here, we have experimentally investigated the symptoms of disease caused by recurrent infestations in a common songbird (Parus major). Birds were exposed three times in succession to ticks collected in a Borrelia endemic area. Health and immune measures were analyzed in order to investigate changes in response to tick infestation and Borrelia infection rate. Nitric oxide levels increased with the Borrelia infection rate, but this effect was increasingly counteracted by mounting tick infestation rates. Tick infestations equally reduced haematocrit during each cycle. But birds overcompensated in their response to tick feeding, having higher haematocrit values during tick-free periods depending on the number of ticks they had been previously exposed to. Body condition showed a similar overshooting response in function of the severity of the Borrelia infection. The observed overcompensation increases the bird’s energetic needs, which may result in an increase in transmission events.

  1. [Clinical aspects of Borrelia burgdorferi infections].

    PubMed

    Neubert, U

    1989-08-15

    Skin lesions due to Borrelia burgdorferi-like erythema migrans, lymphadenosis cutis benigna, and acrodermatitis chronica atrophicans - are hall-marks of a systemic infection, which tends to a chronically relapsing course. Even if the skin lesions are missing, or disappear spontaneously, the infection may persist and affect other organs. This presumption is supported by the outcome of a long-term follow-up study on seropositive forest workers. In association with meningopolyneuritis (Garin-Bujadoux-Bannwarth disease) and acrodermatitis chronica atrophicans - myositis and fasciitis have been recently reported as further possible manifestations of Borrelia burgdorferi infection. Borrelial infection during pregnancy should promptly be treated with antibiotics in high dosages, in order to prevent maternal-fetal transmission of borrelial organisms resulting in stillbirth or congenital defects of the newborn. PMID:2678790

  2. African Relapsing Fever Borreliae Genomospecies Revealed by Comparative Genomics

    PubMed Central

    Elbir, Haitham; Abi-Rached, Laurent; Pontarotti, Pierre; Yoosuf, Niyaz; Drancourt, Michel

    2014-01-01

    Background: Relapsing fever borreliae are vector-borne bacteria responsible for febrile infection in humans in North America, Africa, Asia, and in the Iberian Peninsula in Europe. Relapsing fever borreliae are phylogenetically closely related, yet they differ in pathogenicity and vectors. Their long-term taxonomy, based on geography and vector grouping, needs to be re-apprised in a genomic context. We therefore embarked into genomic analyses of relapsing fever borreliae, focusing on species found in Africa. Results: Genome-wide phylogenetic analyses group Old World Borrelia crocidurae, Borrelia hispanica, B. duttonii, and B. recurrentis in one clade, and New World Borrelia turicatae and Borrelia hermsii in a second clade. Accordingly, average nucleotide identity is 99% among B. duttonii, B. recurrentis, and B. crocidurae and 96% between latter borreliae and B. hispanica while the similarity is 86% between Old World and New World borreliae. Comparative genomics indicates that the Old World relapsing fever B. duttonii, B. recurrentis, B. crocidurae, and B. hispanica have a 2,514-gene pan genome and a 933-gene core genome that includes 788 chromosomal and 145 plasmidic genes. Analyzing the role that natural selection has played in the evolution of Old World borreliae species revealed that 55 loci were under positive diversifying selection, including loci coding for membrane, flagellar, and chemotaxis proteins, three categories associated with adaption to specific niches. Conclusion: Genomic analyses led to a reappraisal of the taxonomy of relapsing fever borreliae in Africa. These analyses suggest that B. crocidurae, B. duttonii, and B. recurrentis are ecotypes of a unique genomospecies, while B. hispanica is a distinct species. PMID:25229054

  3. Purine Salvage Pathways among Borrelia Species▿

    PubMed Central

    Pettersson, Jonas; Schrumpf, Merry E.; Raffel, Sandra J.; Porcella, Stephen F.; Guyard, Cyril; Lawrence, Kevin; Gherardini, Frank C.; Schwan, Tom G.

    2007-01-01

    Genome sequencing projects on two relapsing fever spirochetes, Borrelia hermsii and Borrelia turicatae, revealed differences in genes involved in purine metabolism and salvage compared to those in the Lyme disease spirochete Borrelia burgdorferi. The relapsing fever spirochetes contained six open reading frames that are absent from the B. burgdorferi genome. These genes included those for hypoxanthine-guanine phosphoribosyltransferase (hpt), adenylosuccinate synthase (purA), adenylosuccinate lyase (purB), auxiliary protein (nrdI), the ribonucleotide-diphosphate reductase alpha subunit (nrdE), and the ribonucleotide-diphosphate reductase beta subunit (nrdF). Southern blot assays with multiple Borrelia species and isolates confirmed the presence of these genes in the relapsing fever group of spirochetes but not in B. burgdorferi and related species. TaqMan real-time reverse transcription-PCR demonstrated that the chromosomal genes (hpt, purA, and purB) were transcribed in vitro and in mice. Phosphoribosyltransferase assays revealed that, in general, B. hermsii exhibited significantly higher activity than did the B. burgdorferi cell lysate, and enzymatic activity was observed with adenine, hypoxanthine, and guanine as substrates. B. burgdorferi showed low but detectable phosphoribosyltransferase activity with hypoxanthine even though the genome lacks a discernible ortholog to the hpt gene in the relapsing fever spirochetes. B. hermsii incorporated radiolabeled hypoxanthine into RNA and DNA to a much greater extent than did B. burgdorferi. This complete pathway for purine salvage in the relapsing fever spirochetes may contribute, in part, to these spirochetes achieving high cell densities in blood. PMID:17502392

  4. Laboratory Cultivation and Maintenance of Borrelia miyamotoi.

    PubMed

    Stone, Brandee L; Brissette, Catherine A

    2016-01-01

    Borrelia miyamotoi is a relapsing fever tick-borne pathogen found in Ixodes spp. (hard) ticks. In vitro culturing has proven difficult despite initial reports of cultures maintained in Barbour-Stoenner-Kelly-II (BSK-II) medium. The ability to culture in vitro opens many avenues for investigating the genetics and physiology of bacterial species. This unit describes methods for the maintenance and cultivation of B. miyamotoi in liquid medium. © 2016 by John Wiley & Sons, Inc. PMID:27517334

  5. Is Localized Scleroderma Caused by Borrelia burgdorferi?

    PubMed

    Zinchuk, Alexander N; Kalyuzhna, Lidiya D; Pasichna, Iryna A

    2016-09-01

    Despite considerable achievements in the study of localized scleroderma, the etiology of the disease has not been investigated completely. Borrelia burgdorferi-the agent of Lyme disease-is suggested to be one of the possible etiological factors of localized scleroderma. However, among scientists, this hypothesis is quite controversial. We have conducted investigations of the level of IgM and IgG class antibodies to B. burgdorferi in the serum of patients with localized scleroderma. To rationally substantiate the role of B. burgdorferi in the occurrence of localized scleroderma, thirty-two patients with localized scleroderma treated at an in-patient department were examined. The level of anti-Borrelia antibodies was determined in ELISA. Diagnostic levels of IgM and/or IgG were detected in 18.8% of patients with localized scleroderma, which is more than in the population (p < 0.01). Positive levels of anti-Borrelia antibodies in patients with localized scleroderma confirm the borreliosis nature of the disease, requiring conduction of complex antimicrobial treatment. PMID:27387068

  6. First isolation of Borrelia lusitaniae from a human patient.

    PubMed

    Collares-Pereira, M; Couceiro, S; Franca, I; Kurtenbach, K; Schäfer, S M; Vitorino, L; Gonçalves, L; Baptista, S; Vieira, M L; Cunha, C

    2004-03-01

    The first human isolate of Borrelia lusitaniae recovered from a Portuguese patient with suspected Lyme borreliosis is described. This isolate, from a chronic skin lesion, is also the first human isolate of Borrelia in Portugal. Different phenotypic and molecular methods are used to characterize it. PMID:15004107

  7. First Isolation of Borrelia lusitaniae from a Human Patient

    PubMed Central

    Collares-Pereira, M.; Couceiro, S.; Franca, I.; Kurtenbach, K.; Schäfer, S. M.; Vitorino, L.; Gonçalves, L.; Baptista, S.; Vieira, M. L.; Cunha, C.

    2004-01-01

    The first human isolate of Borrelia lusitaniae recovered from a Portuguese patient with suspected Lyme borreliosis is described. This isolate, from a chronic skin lesion, is also the first human isolate of Borrelia in Portugal. Different phenotypic and molecular methods are used to characterize it. PMID:15004107

  8. Monoclonal Antibodies for the Diagnosis of Borrelia crocidurae.

    PubMed

    Fotso Fotso, Aurélien; Mediannikov, Oleg; Nappez, Claude; Azza, Saïd; Raoult, Didier; Drancourt, Michel

    2016-01-01

    Relapsing fever borreliae, produced by ectoparasite-borne Borrelia species, cause mild to deadly bacteremia and miscarriage. In the perspective of developing inexpensive assays for the rapid detection of relapsing fever borreliae, we produced 12 monoclonal antibodies (MAbs) against Borrelia crocidurae and characterized the two exhibiting the highest titers. P3A10 MAb reacts with the 35.6-kDa flagellin B (flaB) of B. crocidurae while P6D9 MAb recognizes a 35.1-kDa variable-like protein (Vlp) in B. crocidurae and a 35.2-kDa Vlp in Borrelia duttonii. Indirect immunofluorescence assay incorporating relapsing fever and Lyme group borreliae and 11 blood-borne organisms responsible for fever in West Africa confirmed the reactivity of these two MAbs. Combining these two MAbs in indirect immunofluorescence assays detected relapsing fever borreliae including B. crocidurae in ticks and the blood of febrile Senegalese patients. Both antibodies could be incorporated into inexpensive and stable formats suited for the rapid point-of-care diagnosis of relapsing fever. These first-ever MAbs directed against African relapsing fever borreliae are available for the scientific community to promote research in this neglected field. PMID:26598566

  9. Quantification of Cooperativity in Heterodimer-DNA Binding Improves the Accuracy of Binding Specificity Models.

    PubMed

    Isakova, Alina; Berset, Yves; Hatzimanikatis, Vassily; Deplancke, Bart

    2016-05-01

    Many transcription factors (TFs) have the ability to cooperate on DNA elements as heterodimers. Despite the significance of TF heterodimerization for gene regulation, a quantitative understanding of cooperativity between various TF dimer partners and its impact on heterodimer DNA binding specificity models is still lacking. Here, we used a novel integrative approach, combining microfluidics-steered measurements of dimer-DNA assembly with mechanistic modeling of the implicated protein-protein-DNA interactions to quantitatively interrogate the cooperative DNA binding behavior of the adipogenic peroxisome proliferator-activated receptor γ (PPARγ):retinoid X receptor α (RXRα) heterodimer. Using the high throughput MITOMI (mechanically induced trapping of molecular interactions) platform, we derived equilibrium DNA binding data for PPARγ, RXRα, as well as the PPARγ:RXRα heterodimer to more than 300 target DNA sites and variants thereof. We then quantified cooperativity underlying heterodimer-DNA binding and derived an integrative heterodimer DNA binding constant. Using this cooperativity-inclusive constant, we were able to build a heterodimer-DNA binding specificity model that has superior predictive power than the one based on a regular one-site equilibrium. Our data further revealed that individual nucleotide substitutions within the target site affect the extent of cooperativity in PPARγ:RXRα-DNA binding. Our study therefore emphasizes the importance of assessing cooperativity when generating DNA binding specificity models for heterodimers. PMID:26912662

  10. Quantification of Cooperativity in Heterodimer-DNA Binding Improves the Accuracy of Binding Specificity Models*

    PubMed Central

    Isakova, Alina; Berset, Yves; Hatzimanikatis, Vassily; Deplancke, Bart

    2016-01-01

    Many transcription factors (TFs) have the ability to cooperate on DNA elements as heterodimers. Despite the significance of TF heterodimerization for gene regulation, a quantitative understanding of cooperativity between various TF dimer partners and its impact on heterodimer DNA binding specificity models is still lacking. Here, we used a novel integrative approach, combining microfluidics-steered measurements of dimer-DNA assembly with mechanistic modeling of the implicated protein-protein-DNA interactions to quantitatively interrogate the cooperative DNA binding behavior of the adipogenic peroxisome proliferator-activated receptor γ (PPARγ):retinoid X receptor α (RXRα) heterodimer. Using the high throughput MITOMI (mechanically induced trapping of molecular interactions) platform, we derived equilibrium DNA binding data for PPARγ, RXRα, as well as the PPARγ:RXRα heterodimer to more than 300 target DNA sites and variants thereof. We then quantified cooperativity underlying heterodimer-DNA binding and derived an integrative heterodimer DNA binding constant. Using this cooperativity-inclusive constant, we were able to build a heterodimer-DNA binding specificity model that has superior predictive power than the one based on a regular one-site equilibrium. Our data further revealed that individual nucleotide substitutions within the target site affect the extent of cooperativity in PPARγ:RXRα-DNA binding. Our study therefore emphasizes the importance of assessing cooperativity when generating DNA binding specificity models for heterodimers. PMID:26912662

  11. Convergent Synthesis of Two Fluorescent Ebselen-Coumarin Heterodimers.

    PubMed

    Küppers, Jim; Schulz-Fincke, Anna Christina; Palus, Jerzy; Giurg, Mirosław; Skarżewski, Jacek; Gütschow, Michael

    2016-01-01

    The organo-seleniumdrug ebselen exhibits a wide range of pharmacological effects that are predominantly due to its interference with redox systems catalyzed by seleno enzymes, e.g., glutathione peroxidase and thioredoxin reductase. Moreover, ebselen can covalently interact with thiol groups of several enzymes. According to its pleiotropic mode of action, ebselen has been investigated in clinical trials for the prevention and treatment of different ailments. Fluorescence-labeled probes containing ebselen are expected to be suitable for further biological and medicinal studies. We therefore designed and synthesized two coumarin-tagged activity-based probes bearing the ebselen warhead. The heterodimers differ by the nature of the spacer structure, for which-in the second compound-a PEG/two-amide spacer was introduced. The interaction of this probe and of ebselen with two cysteine proteases was investigated. PMID:27399725

  12. Synergistic transmembrane alignment of the antimicrobial heterodimer PGLa/magainin.

    PubMed

    Tremouilhac, Pierre; Strandberg, Erik; Wadhwani, Parvesh; Ulrich, Anne S

    2006-10-27

    The antimicrobial activity of amphipathic alpha-helical peptides is usually attributed to the formation of pores in bacterial membranes, but direct structural information about such a membrane-bound state is sparse. Solid state (2)H-NMR has previously shown that the antimicrobial peptide PGLa undergoes a concentration-dependent realignment from a surface-bound S-state to a tilted T-state. The corresponding change in helix tilt angle from 98 to 125 degrees was interpreted as the formation of PGLa/magainin heterodimers residing on the bilayer surface. Under no conditions so far, has an upright membrane-inserted I-state been observed in which a transmembrane helix alignment would be expected. Here, we have demonstrated that PGLa is able to assume such an I-state in a 1:1 mixture with magainin 2 at a peptide-to-lipid ratio as low as 1:100 in dimyristoylphosphatidylcholine/dimyristoylphosphatidylglycerol model membranes. This (2)H-NMR analysis is based on seven orientational constraints from Ala-3,3,3-d(3) substituted in a non-perturbing manner for four native Ala residues as well as two Ile and one Gly. The observed helix tilt of 158 degrees is rationalized by the formation of heterodimers. This structurally synergistic effect between the two related peptides from the skin of Xenopus laevis correlates very well with their known functional synergistic mode of action. To our knowledge, this example of PGLa is the first case where an alpha-helical antimicrobial peptide is directly shown to assume a transmembrane state that is compatible with the postulated toroidal wormhole pore structure. PMID:16877761

  13. Statistical analysis of the distribution of amino acids in Borrelia burgdorferi genome under different genetic codes

    NASA Astrophysics Data System (ADS)

    García, José A.; Alvarez, Samantha; Flores, Alejandro; Govezensky, Tzipe; Bobadilla, Juan R.; José, Marco V.

    2004-10-01

    The genetic code is considered to be universal. In order to test if some statistical properties of the coding bacterial genome were due to inherent properties of the genetic code, we compared the autocorrelation function, the scaling properties and the maximum entropy of the distribution of distances of amino acids in sequences obtained by translating protein-coding regions from the genome of Borrelia burgdorferi, under different genetic codes. Overall our results indicate that these properties are very stable to perturbations made by altering the genetic code. We also discuss the evolutionary likely implications of the present results.

  14. Genomic Characteristics of Chinese Borrelia burgdorferi Isolates

    PubMed Central

    Hou, Xuexia; Zhang, Lin; Zhang, Yuanyuan; Liu, Huixin; Liu, Wei; Chen, Chen; Wan, Kanglin

    2016-01-01

    In China, B. burgdorferi, B.garinii, B. afzelii and B. yangtze sp. nov have been reported; B.garinii and B. afzelii are the main pathogenic genotypes. But until now only one Chinese strain was reported with whole genome sequence. In order to further understand the genomic characteristics and diversity of Chinese Borrelia strains, 5 isolates from China were sequenced and compared with the whole genome sequences of strains in other areas. The results showed a high degree of conservation within the linear chromosome of Chinese strains, whereas plasmid showed a much larger diversity according to the majority genomic information of plasmids. The genome sequences of the five Chinese strains were compared with the corresponding reference strains, respectively, according to the genospecies. Pairwise analysis demonstrates that there are only 70 SNPs between the genomes of CS4 and B31. However, there are many more SNPs between the genomes of QX-S13 and VS116, PD91 and PBi, FP1 and PKo, R9 and Pko, respectively. Gene comparison showed some important different genes. OspA was one of the important different genes. Comparative genomic studies have found that OspA gene sequences of PD91 and R9 had great differences compared with the sequence of B31. OspA gene sequence of R9 had a 96bp deletion; OspA gene of PD91 had two deletions: 9bp and 10 bp. To conclude, we showed the genomic characteristics of four genotype Chinese B. burgdorferi strains. The genomic sequence of B. yangtze sp. nov and differences from B. valaisiana were first reported. Comparative analysis of Chinese strains with the different Borrelia species from other areas will help us to understand evolution and pathogenesis of Chinese Borrelia burgdorferi strains. PMID:27093540

  15. Borrelia infection and risk of non-Hodgkin lymphoma

    PubMed Central

    Melbye, Mads; Munksgaard, Lars; Smedby, Karin Ekström; Rostgaard, Klaus; Glimelius, Bengt; Chang, Ellen T.; Roos, Göran; Hansen, Mads; Adami, Hans-Olov; Hjalgrim, Henrik

    2008-01-01

    Reports of the presence of Borrelia burgdorferi DNA in malignant lymphomas have raised the hypothesis that infection with B burgdorferi may be causally related to non-Hodgkin lymphoma (NHL) development. We conducted a Danish-Swedish case-control study including 3055 NHL patients and 3187 population controls. History of tick bite or Borrelia infection was ascertained through structured telephone interviews and through enzyme-linked immunosorbent assay serum analyses for antibodies against B burgdorferi in a subset of 1579 patients and 1358 controls. Statistical associations with risk of NHL, including histologic subtypes, were assessed by logistic regression. Overall risk of NHL was not associated with self-reported history of tick bite (odds ratio [OR] = 1.0; 95% confidence interval: 0.9-1.1), Borrelia infection (OR = 1.3 [0.96-1.8]) or the presence of anti-Borrelia antibodies (OR = 1.3 [0.9-2.0]). However, in analyses of NHL subtypes, self-reported history of B burgdorferi infection (OR = 2.5 [1.2-5.1]) and seropositivity for anti-Borrelia antibodies (OR = 3.6 [1.8-7.4]) were both associated with risk of mantle cell lymphoma. Notably, this specific association was also observed in persons who did not recall Borrelia infection yet tested positive for anti-Borrelia antibodies (OR = 4.2 [2.0-8.9]). Our observations suggest a previously unreported association between B burgdorferi infection and risk of mantle cell lymphoma. PMID:18424667

  16. Relapsing Fever Borreliae: A Global Review.

    PubMed

    Cutler, Sally J

    2015-12-01

    Relapsing fever borreliae were notorious and feared infectious agents that earned their place in history through their devastating impact as causes of both epidemic and endemic infection. They are now considered more as an oddity, and their burden of infection is largely overshadowed by other infections such as malaria, which presents in a similar clinical way. Despite this, they remain the most common bacterial infection in some developing countries. Transmitted by soft ticks or lice, these fascinating spirochetes have evolved a myriad of mechanisms to survive within their diverse environments. PMID:26593261

  17. The NF45/NF90 Heterodimer Contributes to the Biogenesis of 60S Ribosomal Subunits and Influences Nucleolar Morphology

    PubMed Central

    Wandrey, Franziska; Montellese, Christian; Koos, Krisztian; Badertscher, Lukas; Bammert, Lukas; Cook, Atlanta G.; Zemp, Ivo; Horvath, Peter

    2015-01-01

    The interleukin enhancer binding factors ILF2 (NF45) and ILF3 (NF90/NF110) have been implicated in various cellular pathways, such as transcription, microRNA (miRNA) processing, DNA repair, and translation, in mammalian cells. Using tandem affinity purification, we identified human NF45 and NF90 as components of precursors to 60S (pre-60S) ribosomal subunits. NF45 and NF90 are enriched in nucleoli and cosediment with pre-60S ribosomal particles in density gradient analysis. We show that association of the NF45/NF90 heterodimer with pre-60S ribosomal particles requires the double-stranded RNA binding domains of NF90, while depletion of NF45 and NF90 by RNA interference leads to a defect in 60S biogenesis. Nucleoli of cells depleted of NF45 and NF90 have altered morphology and display a characteristic spherical shape. These effects are not due to impaired rRNA transcription or processing of the precursors to 28S rRNA. Consistent with a role of the NF45/NF90 heterodimer in nucleolar steps of 60S subunit biogenesis, downregulation of NF45 and NF90 leads to a p53 response, accompanied by induction of the cyclin-dependent kinase inhibitor p21/CIP1, which can be counteracted by depletion of RPL11. Together, these data indicate that NF45 and NF90 are novel higher-eukaryote-specific factors required for the maturation of 60S ribosomal subunits. PMID:26240280

  18. The orphan nuclear receptor small heterodimer partner mediates male infertility induced by diethylstilbestrol in mice

    PubMed Central

    Volle, David H.; Decourteix, Mélanie; Garo, Erwan; McNeilly, Judy; Fenichel, Patrick; Auwerx, Johan; McNeilly, Alan S.; Schoonjans, Kristina; Benahmed, Mohamed

    2009-01-01

    Studies in rodents have shown that male sexual function can be disrupted by fetal or neonatal administration of compounds that alter endocrine homeostasis, such as the synthetic nonsteroidal estrogen diethylstilbestrol (DES). Although the molecular basis for this effect remains unknown, estrogen receptors likely play a critical role in mediating DES-induced infertility. Recently, we showed that the orphan nuclear receptor small heterodimer partner (Nr0b2), which is both a target gene and a transcriptional repressor of estrogen receptors, controls testicular function by regulating germ cell entry into meiosis and testosterone synthesis. We therefore hypothesized that some of the harmful effects of DES on testes could be mediated through Nr0b2. Here, we present data demonstrating that Nr0b2 deficiency protected mice against the negative effects of DES on testis development and function. During postnatal development, Nr0b2-null mice were resistant to DES-mediated inhibition of germ cell differentiation, which may be the result of interference by Nr0b2 with retinoid signals that control meiosis. Adult Nr0b2-null male mice were also protected against the effects of DES; however, we suggest that this phenomenon was due to the removal of the repressive effects of Nr0b2 on steroidogenesis. Together, these data demonstrate that Nr0b2 plays a critical role in the pathophysiological changes induced by DES in the mouse testis. PMID:19884658

  19. Structure-guided development of heterodimer-selective GPCR ligands

    PubMed Central

    Hübner, Harald; Schellhorn, Tamara; Gienger, Marie; Schaab, Carolin; Kaindl, Jonas; Leeb, Laurin; Clark, Timothy; Möller, Dorothee; Gmeiner, Peter

    2016-01-01

    Crystal structures of G protein-coupled receptor (GPCR) ligand complexes allow a rational design of novel molecular probes and drugs. Here we report the structure-guided design, chemical synthesis and biological investigations of bivalent ligands for dopamine D2 receptor/neurotensin NTS1 receptor (D2R/NTS1R) heterodimers. The compounds of types 1–3 consist of three different D2R pharmacophores bound to an affinity-generating lipophilic appendage, a polyethylene glycol-based linker and the NTS1R agonist NT(8-13). The bivalent ligands show binding affinity in the picomolar range for cells coexpressing both GPCRs and unprecedented selectivity (up to three orders of magnitude), compared with cells that only express D2Rs. A functional switch is observed for the bivalent ligands 3b,c inhibiting cAMP formation in cells singly expressing D2Rs but stimulating cAMP accumulation in D2R/NTS1R-coexpressing cells. Moreover, the newly synthesized bivalent ligands show a strong, predominantly NTS1R-mediated β-arrestin-2 recruitment at the D2R/NTS1R-coexpressing cells. PMID:27457610

  20. Drosophila Stathmins Bind Tubulin Heterodimers with High and Variable Stoichiometries*

    PubMed Central

    Lachkar, Sylvie; Lebois, Marion; Steinmetz, Michel O.; Guichet, Antoine; Lal, Neha; Curmi, Patrick A.; Sobel, André; Ozon, Sylvie

    2010-01-01

    In vertebrates, stathmins form a family of proteins possessing two tubulin binding repeats (TBRs), which each binds one soluble tubulin heterodimer. The stathmins thus sequester two tubulins in a phosphorylation-dependent manner, providing a link between signal transduction and microtubule dynamics. In Drosophila, we show here that a single stathmin gene (stai) encodes a family of D-stathmin proteins. Two of the D-stathmins are maternally deposited and then restricted to germ cells, and the other two are detected in the nervous system during embryo development. Like in vertebrates, the nervous system-enriched stathmins contain an N-terminal domain involved in subcellular targeting. All the D-stathmins possess a domain containing three or four predicted TBRs, and we demonstrate here, using complementary biochemical and biophysical methods, that all four predicted TBR domains actually bind tubulin. D-stathmins can indeed bind up to four tubulins, the resulting complex being directly visualized by electron microscopy. Phylogenetic analysis shows that the presence of regulated multiple tubulin sites is a conserved characteristic of stathmins in invertebrates and allows us to predict key residues in stathmin for the binding of tubulin. Altogether, our results reveal that the single Drosophila stathmin gene codes for a stathmin family similar to the multigene vertebrate one, but with particular tubulin binding properties. PMID:20145240

  1. Drosophila stathmins bind tubulin heterodimers with high and variable stoichiometries.

    PubMed

    Lachkar, Sylvie; Lebois, Marion; Steinmetz, Michel O; Guichet, Antoine; Lal, Neha; Curmi, Patrick A; Sobel, André; Ozon, Sylvie

    2010-04-01

    In vertebrates, stathmins form a family of proteins possessing two tubulin binding repeats (TBRs), which each binds one soluble tubulin heterodimer. The stathmins thus sequester two tubulins in a phosphorylation-dependent manner, providing a link between signal transduction and microtubule dynamics. In Drosophila, we show here that a single stathmin gene (stai) encodes a family of D-stathmin proteins. Two of the D-stathmins are maternally deposited and then restricted to germ cells, and the other two are detected in the nervous system during embryo development. Like in vertebrates, the nervous system-enriched stathmins contain an N-terminal domain involved in subcellular targeting. All the D-stathmins possess a domain containing three or four predicted TBRs, and we demonstrate here, using complementary biochemical and biophysical methods, that all four predicted TBR domains actually bind tubulin. D-stathmins can indeed bind up to four tubulins, the resulting complex being directly visualized by electron microscopy. Phylogenetic analysis shows that the presence of regulated multiple tubulin sites is a conserved characteristic of stathmins in invertebrates and allows us to predict key residues in stathmin for the binding of tubulin. Altogether, our results reveal that the single Drosophila stathmin gene codes for a stathmin family similar to the multigene vertebrate one, but with particular tubulin binding properties. PMID:20145240

  2. Borrelia burgdorferi bind to epithelial cell proteoglycans.

    PubMed Central

    Isaacs, R D

    1994-01-01

    Borrelia burgdorferi adhere to mammalian cells in vitro but neither the ligand(s) nor the receptor(s) has (have) been clearly established. Using an in vitro attachment-inhibition assay, a B. burgdorferi attachment mechanism has been identified. Heparin, heparan sulfate, and dermatan sulfate reduced the attachment of virulent B. burgdorferi strain 297 to HeLa cells by approximately 60%. In addition, virulent, but not avirulent, B. burgdorferi strains B31, N40, and HB19 demonstrated heparin attachment-inhibition. Attachment to Chinese hamster ovary cells deficient in heparan sulfate proteoglycans was reduced by 68% compared to attachment to wild-type cells and was identical to attachment at maximum heparin inhibition to the wild-type cells. Pretreatment of HeLa cell monolayers with heparitinase, heparinase, and chondroitinase ABC, but not with chondroitinase AC, reduced borrelial attachment by approximately 50%. A moderately high affinity, low copy number, promiscuous B. burgdorferi glycosaminoglycan receptor was demonstrated by equilibrium binding studies. A 39-kD polypeptide, purified by heparin affinity chromatography from Triton X-100 extracts derived from virulent borrelia, was a candidate for this receptor. These studies indicate that one mode of B. burgdorferi attachment to eukaryotic cells is mediated by a borrelial glycosaminoglycan receptor attaching to surface-exposed proteoglycans on mammalian cells. Images PMID:8113413

  3. Colony formation and morphology in Borrelia burgdorferi.

    PubMed

    Kurtti, T J; Munderloh, U G; Johnson, R C; Ahlstrand, G G

    1987-11-01

    Two strains of Borrelia burgdorferi, B31 and 297, formed colonies when plated onto Barbour-Stoenner-Kelly medium solidified with agarose (1.3%) and incubated in a candle jar at 34 degrees C. Colonies differing in morphology were observed in both strains after 2 to 3 weeks of incubation. Strain B31 colonies were either compact, round (mean diameter, 0.43 mm), and restricted to the surface of the agarose medium or diffuse (mean diameter, 1.80 mm) and penetrating into the solid medium. Strain 297 colonies (mean diameter, 1.43 mm) either showed a raised center surrounded by a diffuse ring of spirochetes or consisted of numerous small spirochetal aggregates. Both colony types expanded into the agarose medium. Scanning electron and light microscopy confirmed that the colonies were formed by spirochetes. Twisted tangles of intertwined spirochetes were visible on the surface, with numerous spherical bodies among them, especially in the central regions. At the periphery, the borreliae were more loosely packed, and individual coils were discernible. PMID:3693538

  4. Proteome Analysis of Borrelia burgdorferi Response to Environmental Change

    SciTech Connect

    Angel, Thomas E.; Luft, Benjamin J.; Yang, Xiaohua; Nicora, Carrie D.; Camp, David G.; Jacobs, Jon M.; Smith, Richard D.

    2010-11-02

    We examined global changes in protein expression in the B31 strain of Borrelia burgdorferi, in response to two environmental cues (pH and temperature) chosen for their reported similarity to those encountered at different stages of the organism’s life cycle. Multidimensional nano-liquid chromatographic separations coupled with tandem mass spectrometry were used to examine the array of proteins (i.e., the proteome) of B. burgdorferi for different pH and temperature culture conditions. Changes in pH and temperature elicited in vitro adaptations of this spirochete known to cause Lyme disease and led to alterations in protein expression that are associated with increased microbial pathogenesis. We identified 1031 proteins that represent 59% of the annotated genome of B. burgdorferi and elucidated a core proteome of 414 proteins that were present in all environmental conditions investigated. Observed changes in protein abundances indicated varied replicon usage, as well as proteome functional distributions between the in vitro cell culture conditions. Surprisingly, the pH and temperature conditions that mimicked B. burgdorferi residing in the gut of a fed tick showed a marked reduction in protein diversity. Additionally, the results provide us with leading candidates for exploring how B. burgdorferi adapts to and is able to survive in a wide variety of environmental conditions and lay a foundation for planned in situ studies of B. burgdorferi isolated from the tick midgut and infected animals.

  5. Electronic structure of the primary electron donor of Blastochloris viridis heterodimer mutants : high field EPR study.

    SciTech Connect

    Ponomarenko, N. S.; Poluektov, O. G.; Bylina, E. J.; Norris, J. R.; Chemical Sciences and Engineering Division; Univ. of Chicago

    2010-09-01

    High-field electron paramagnetic resonance (HF EPR) has been employed to investigate the primary electron donor electronic structure of Blastochloris viridis heterodimer mutant reaction centers (RCs). In these mutants the amino acid substitution His(M200)Leu or His(L173)Leu eliminates a ligand to the primary electron donor, resulting in the loss of a magnesium in one of the constituent bacteriochlorophylls (BChl). Thus, the native BChl/BChl homodimer primary donor is converted into a BChl/bacteriopheophytin (BPhe) heterodimer. The heterodimer primary donor radical in chemically oxidized RCs exhibits a broadened EPR line indicating a highly asymmetric distribution of the unpaired electron over both dimer constituents. Observed triplet state EPR signals confirm localization of the excitation on the BChl half of the heterodimer primary donor. Theoretical simulation of the triplet EPR lineshapes clearly shows that, in the case of mutants, triplet states are formed by an intersystem crossing mechanism in contrast to the radical pair mechanism in wild type RCs. Photooxidation of the mutant RCs results in formation of a BPhe anion radical within the heterodimer pair. The accumulation of an intradimer BPhe anion is caused by the substantial loss of interaction between constituents of the heterodimer primary donor along with an increase in the reduction potential of the heterodimer primary donor D/D{sup +} couple. This allows oxidation of the cytochrome even at cryogenic temperatures and reduction of each constituent of the heterodimer primary donor individually. Despite a low yield of primary donor radicals, the enhancement of the semiquinone-iron pair EPR signals in these mutants indicates the presence of kinetically viable electron donors.

  6. Noggin regulation of bone morphogenetic protein (BMP) 2/7 heterodimer activity in vitro

    PubMed Central

    Zhu, Wei; Kim, Jaehon; Cheng, Christina; Rawlins, Bernard A.; Boachie-Adjei, Oheneba; Crystal, Ronald G.; Hidaka, Chisa

    2010-01-01

    Bone morphogenic proteins (BMPs) are growth factors important for skeletal development and bone growth. Noggin, one of the soluble BMP antagonists, regulates the action of BMPs on mesenchymal precursor cells, partially through a feedback type of inhibition. In this study, we constructed a novel BMP2/7 ‘fusion gene’ that encodes both BMP2 and BMP7 genes in tandem by a linker. Polymerase chain reaction (PCR) and Western blotting showed that the BMP2/7 fusion gene construct led to the production of BMP2/7 heterodimers in A549 ‘producer’ cells. When applied to C2C12 myoblastic cells, BMP2/7 heterodimers increased alkaline phosphatase (ALP) activity and osteocalcin (OCN) expression (markers of osteoblastic differentiation) more effectively than either BMP2 or BMP7 homodimers. Moreover, this heterodimer induced significantly lower levels of Noggin expression in C2C12 cells than respective homodimers at similar doses. The addition of Noggin did not affect the heterodimer’s activities in increasing osteoblastic differentiation in C2C12 cells. In contrast, BMP2 and BMP7 homodimers were largely inhibited by Noggin. Our finding suggests that the ‘fusion gene’ construct led to the production of bioactive BMP2/7 heterodimers, which were not antagonized by Noggin as effectively as it to BMP homodimers. The weaker Noggin antagonism on BMP heterodimers compared to homodimers may contribute to increased osteogenic potency of heterodimers in vitro and in vivo. PMID:16488673

  7. Autophagy suppresses host adaptive immune responses toward Borrelia burgdorferi.

    PubMed

    Buffen, Kathrin; Oosting, Marije; Li, Yang; Kanneganti, Thirumala-Devi; Netea, Mihai G; Joosten, Leo A B

    2016-09-01

    We have previously demonstrated that inhibition of autophagy increased the Borrelia burgdorferi induced innate cytokine production in vitro, but little is known regarding the effect of autophagy on in vivo models of Borrelia infection. Here, we showed that ATG7-deficient mice that were intra-articular injected with Borrelia spirochetes displayed increased joint swelling, cell influx, and enhanced interleukin-1β and interleukin-6 production by inflamed synovial tissue. Because both interleukin-1β and interleukin-6 are linked to the development of adaptive immune responses, we examine the function of autophagy on Borrelia induced adaptive immunity. Human peripheral blood mononuclear cells treated with autophagy inhibitors showed an increase in interleukin-17, interleukin-22, and interferon-γ production in response to exposure to Borrelia burgdorferi. Increased IL-17 production was dependent on IL-1β release but, interestingly, not on interleukin-23 production. In addition, cytokine quantitative trait loci in ATG9B modulate the Borrelia induced interleukin-17 production. Because high levels of IL-17 have been found in patients with confirmed, severe, chronic borreliosis, we propose that the modulation of autophagy may be a potential target for anti-inflammatory therapy in patients with persistent Lyme disease. PMID:27101991

  8. Diversity and Distribution of Borrelia hermsii

    PubMed Central

    Raffel, Sandra J.; Schrumpf, Merry E.; Porcella, Stephen F.

    2007-01-01

    Borrelia hermsii is the most common cause of tickborne relapsing fever in North America. DNA sequences of the 16S–23S rDNA noncoding intergenic spacer (IGS) region were determined for 37 isolates of this spirochete. These sequences distinguished the 2 genomic groups of B. hermsii identified previously with other loci. Multiple IGS genotypes were identified among isolates from an island, which suggested that birds might play a role in dispersing these spirochetes in nature. In support of this theory, all stages of the tick vector Ornithodoros hermsi fed successfully on birds in the laboratory and advanced in their life cycle. B. hermsii produced a detectable spirochetemia in 1 chicken inoculated subcutaneously. Additional work is warranted to explore the role of birds as enzootic hosts for this relapsing fever spirochete. PMID:17552097

  9. Biomechanics of Borrelia burgdorferi Vascular Interactions.

    PubMed

    Ebady, Rhodaba; Niddam, Alexandra F; Boczula, Anna E; Kim, Yae Ram; Gupta, Nupur; Tang, Tian Tian; Odisho, Tanya; Zhi, Hui; Simmons, Craig A; Skare, Jon T; Moriarty, Tara J

    2016-09-01

    Systemic dissemination of microbes is critical for progression of many infectious diseases and is associated with most mortality due to bacterial infection. The physical mechanisms mediating a key dissemination step, bacterial association with vascular endothelia in blood vessels, remain unknown. Here, we show that endothelial interactions of the Lyme disease spirochete Borrelia burgdorferi under physiological shear stress mechanistically resemble selectin-dependent leukocyte rolling. Specifically, these interactions are mediated by transfer of mechanical load along a series of adhesion complexes and are stabilized by tethers and catch bond properties of the bacterial adhesin BBK32. Furthermore, we found that the forces imposed on adhesive bonds under flow may be small enough to permit active migration driven by bacterial flagellar motors. These findings provide insight into the biomechanics of bacterial-vascular interactions and demonstrate that disseminating bacteria and circulating host immune cells share widely conserved mechanisms for interacting with endothelia under physiological shear stress. PMID:27568563

  10. Molecular insight of isotypes specific β-tubulin interaction of tubulin heterodimer with noscapinoids.

    PubMed

    Santoshi, Seneha; Naik, Pradeep K

    2014-07-01

    Noscapine and its derivatives bind stoichiometrically to tubulin, alter its dynamic instability and thus effectively inhibit the cellular proliferation of a wide variety of cancer cells including many drug-resistant variants. The tubulin molecule is composed of α- and β-tubulin, which exist as various isotypes whose distribution and drug-binding properties are significantly different. Although the noscapinoids bind to a site overlapping with colchicine, their interaction is more biased towards β-tubulin. In fact, their precise interaction and binding affinity with specific isotypes of β-tubulin in the αβ-heterodimer has never been addressed. In this study, the binding affinity of a panel of noscapinoids with each type of tubulin was investigated computationally. We found that the binding score of a specific noscapinoid with each type of tubulin isotype is different. Specifically, amino-noscapine has the highest binding score of -6.4, -7.2, -7.4 and -7.3 kcal/mol with αβI, αβII, αβIII and αβIV isotypes, respectively. Similarly 10 showed higher binding affinity of -6.8 kcal/mol with αβV, whereas 8 had the highest binding affinity of -7.2, -7.1 and -7.2 kcal/mol, respectively with αβVI, αβVII and αβVIII isotypes. More importantly, both amino-noscapine and its clinical derivative, bromo-noscapine have the highest binding affinity of -46.2 and -38.1 kcal/mol against αβIII (overexpression of αβIII has been associated with resistance to a wide range of chemotherapeutic drugs for several human malignancies) as measured using MM-PBSA. Knowledge of the isotype specificity of the noscapinoids may allow for development of novel therapeutic agents based on this class of drugs. PMID:24916062

  11. New Borrelia species detected in ixodid ticks in Oromia, Ethiopia.

    PubMed

    Kumsa, Bersissa; Socolovschi, Cristina; Raoult, Didier; Parola, Philippe

    2015-04-01

    Little is known about Borrelia species transmitted by hard ticks in Ethiopia. The present study was conducted from November 2011 through March 2014 to address the occurrence and molecular identity of these bacteria in ixodid ticks infesting domestic animals in Oromia, Ethiopia. A total of 767 ixodid ticks collected from domestic animals were screened for Borrelia DNA by quantitative (q) real-time PCR followed by standard PCR and sequencing to identify the species. Overall, 3.8% (29/767) of the tested ticks were positive for Borrelia DNA, including 8/119 (6.7%) Amblyomma cohaerens, 1/42 (2.4%) Am. gemma, 3/53 (5.7%) Am. variegatum, 5/22 (22.7%) Amblyomma larvae, 3/60 (5%) Amblyomma nymphs, 2/139 (1.4%) Rhipicephalus (Boophilus) decoloratus, 2/31 (6.4%) Rh. decoloratus nymphs, and 5/118 (4.2%) Rh. pulchellus using 16S genus-specific qPCR. The prevalence of Borrelia DNA was significantly higher in genus Amblyomma (20/298, 6.7%) than in the genus Rhipicephalus (9/417, 2.1%) ticks (P=0.001). Sequencing of PCR products from the flaB and 16S rRNA genes of Borrelia spp. from Amblyomma ticks showed the presence of a new species between the relapsing fever and Lyme disease groups. However, Borrelia sp. detected in Rhipicephalus ticks clustered with B. theileri/B. lonestari. The human pathogenicity of the Borrelia sp. detected in Amblyomma ticks from Ethiopia has not yet been investigated, whereas the Borrelia sp. detected in Rhipicephalus ticks in our study is the causative agent of bovine borreliosis in cattle and may have veterinary importance in different parts of Ethiopia. Furthermore, the detection of previously unrecognized Borrelia species in Amblyomma and Rhipicephalus ticks in Ethiopia generates additional questions concerning the bacterial fauna in hard ticks and will prompt researchers to perform detailed studies for better understanding of ixodid ticks associated bacteria. PMID:25843811

  12. Short-term stability of Borrelia garinii in cerebrospinal fluid.

    PubMed

    Berenová, Dagmar; Krsek, Daniel; Šípková, Lenka; Lukavská, Alena; Malý, Marek; Kurzová, Zuzana; Hořejší, Jan; Kodym, Petr

    2016-01-01

    The aim of our study was to find out the optimal conditions for short-term storage of cerebrospinal fluid (CSF) samples for direct diagnosis of Lyme disease. A mixture of Borrelia-negative CSFs spiked with a defined amount of cultured Borrelia garinii was used. Borrelia stability was investigated over 7 days at four different temperatures [room temperature (RT), +4, -20 and -70 °C]. Quantitative changes in CSF Borrelia were measured by quantitative PCR (qPCR), and morphological changes in the spirochetes were observed by transmission electron microscopy (TEM). These qPCR results were statistically evaluated. We found +4 °C to be an optimal temperature for short-term storage of CSF samples intended for TEM observation. There was no significant difference between the temperatures tested in the average quantity of Borrelia measured by qPCR. On the contrary, electron optical diagnosis of frozen samples and samples stored at RT showed destructive morphological changes and decreased spirochete counts. Our results show that optimal conditions for the pre-analytical phase of investigation of one type of material can differ depending on the diagnostic method employed. PMID:26104540

  13. Transstadial transmission of Borrelia turcica in Hyalomma aegyptium ticks.

    PubMed

    Kalmár, Zsuzsa; Cozma, Vasile; Sprong, Hein; Jahfari, Setareh; D'Amico, Gianluca; Mărcuțan, Daniel I; Ionică, Angela M; Magdaş, Cristian; Modrý, David; Mihalca, Andrei D

    2015-01-01

    Borrelia turcica comprises the third major group of arthropod-transmitted borreliae and is phylogenetically divergent from other Borrelia groups. The novel group of Borrelia was initially isolated from Hyalomma aegyptium ticks in Turkey and it was recently found in blood and multiple organs of tortoises exported from Jordan to Japan. However, the ecology of these spirochetes and their development in ticks or the vertebrate hosts were not investigated in detail; our aims were to isolate the pathogen and to evaluate the possibility of transstadial transmission of Borrelia turcica by H. aegyptium ticks. Ticks were collected from Testudo graeca tortoises during the summer of 2013 from southeastern Romania. Engorged nymphs were successfully molted to the adult stage. Alive B. turcica was isolated from molted ticks by using Barbour-Stoenner-Kelly (BSK) II medium. Four pure cultures of spirochetes were obtained and analyzed by PCR and sequencing. Sequence analysis of glpQ, gyrB and flaB revealed 98%-100% similarities with B. turcica. H. aegyptium ticks collected from T. graeca tortoises were able to pass the infection with B. turcica via transstadial route, suggesting its vectorial capacity. PMID:25695663

  14. Transstadial Transmission of Borrelia turcica in Hyalomma aegyptium Ticks

    PubMed Central

    Kalmár, Zsuzsa; Cozma, Vasile; Sprong, Hein; Jahfari, Setareh; D’Amico, Gianluca; Mărcuțan, Daniel I.; Ionică, Angela M.; Magdaş, Cristian; Modrý, David; Mihalca, Andrei D.

    2015-01-01

    Borrelia turcica comprises the third major group of arthropod-transmitted borreliae and is phylogenetically divergent from other Borrelia groups. The novel group of Borrelia was initially isolated from Hyalomma aegyptium ticks in Turkey and it was recently found in blood and multiple organs of tortoises exported from Jordan to Japan. However, the ecology of these spirochetes and their development in ticks or the vertebrate hosts were not investigated in detail; our aims were to isolate the pathogen and to evaluate the possibility of transstadial transmission of Borrelia turcica by H. aegyptium ticks. Ticks were collected from Testudo graeca tortoises during the summer of 2013 from southeastern Romania. Engorged nymphs were successfully molted to the adult stage. Alive B. turcica was isolated from molted ticks by using Barbour-Stoenner-Kelly (BSK) II medium. Four pure cultures of spirochetes were obtained and analyzed by PCR and sequencing. Sequence analysis of glpQ, gyrB and flaB revealed 98%–100% similarities with B. turcica. H. aegyptium ticks collected from T. graeca tortoises were able to pass the infection with B. turcica via transstadial route, suggesting its vectorial capacity. PMID:25695663

  15. Global ecology and epidemiology of Borrelia garinii spirochetes

    PubMed Central

    Comstedt, Pär; Jakobsson, Tobias; Bergström, Sven

    2011-01-01

    Lyme borreliosis (LB) is a tick-transmitted infectious disease caused by Borrelia burgdorferi sensu lato (s. l.). In Europe, three different Borrelia species are the main causative agents of LB: B. burgdorferi sensu stricto (s.s.), Borrelia afzelii, and Borrelia garinii. The latter depends heavily on birds as its main reservoir hosts. In fact, birds can act both as biological carriers of Borrelia and transporters of infected ticks. The seasonal migration of many bird species not only aid in the spread of B. garinii to new foci but also influence the high level of diversity found within this species. B. garinii have been isolated not only from terrestrial birds in Europe, but also from seabirds worldwide, and homology between isolates in these two different infection cycles suggests an overlap and exchange of strains. In addition, it has been shown that birds can maintain and spread B. garinii genotypes associated with LB in humans. This review article discusses the importance of birds in the ecology and epidemiology of B. garinii spirochetes. PMID:22957111

  16. PCl3-C6H6 heterodimers: evidence for Pπ phosphorus bonding at low temperatures.

    PubMed

    Ramanathan, N; Sankaran, K; Sundararajan, K

    2016-07-28

    A phosphorous trichloride (PCl3)-benzene (C6H6) heterodimer was generated in a low temperature N2 matrix and was characterized using infrared spectroscopy. The structure of the heterodimer produced in the matrix isolation experiment was discerned through ab initio computations. Computations disclosed that the experimentally detected dimer is stabilized through strong non-covalent phosphorus bonded Pπ interaction, considered as a class of pnicogen bonding. This experimentally unmapped Pπ interaction so far has been reconnoitered using atoms in molecules and natural bond orbital and energy decomposition analyses. The influence of substitutions on both the PCl3 and C6H6 monomeric units of the heterodimer was subsequently examined to understand the strength of Pπ interaction as a result of these substitutions. PMID:27374927

  17. Active heterodimers are formed from human DNA topoisomerase II alpha and II beta isoforms.

    PubMed Central

    Biersack, H; Jensen, S; Gromova, I; Nielsen, I S; Westergaard, O; Andersen, A H

    1996-01-01

    DNA topoisomerase II is a nuclear enzyme essential for chromosome dynamics and DNA metabolism. In mammalian cells, two genetically and biochemically distinct topoisomerase II forms exist, which are designated topoisomerase II alpha and topoisomerase II beta. In our studies of human topoisomerase II, we have found that a substantial fraction of the enzyme exists as alpha/beta heterodimers in HeLa cells. The ability to form heterodimers was verified when human topoisomerases II alpha and II beta were coexpressed in yeast and investigated in a dimerization assay. Analysis of purified heterodimers shows that these enzymes maintain topoisomerase II specific catalytic activities. The natural existence of an active heterodimeric subclass of topoisomerase II merits attention whenever topoisomerases II alpha and II beta function, localization, and cell cycle regulation are investigated. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:8710863

  18. Tubulin-specific Chaperones: Components of a Molecular Machine that Assembles the α/β Heterodimer

    PubMed Central

    Tian, Guoling; Cowan, Nicholas J.

    2016-01-01

    The tubulin heterodimer consists of one α- and one β-tubulin polypeptide. Neither protein can partition to the native state or assemble into polymerization competent heterodimers without the concerted action of a series of chaperone proteins including five tubulin-specific chaperones termed TBCA-TBCE. TBCA and TBCB bind to and stabilize newly synthesized quasi-native β- and α-tubulin polypeptides following their generation via multiple rounds of ATP-dependent interaction with the cytosolic chaperonin, CCT. There is free exchange β-tubulin between TBCA and TBCD, and of α-tubulin between TBCB and TBCE, resulting in the formation of TBCD/β and TBCE/α, respectively. The latter two complexes interact, forming a supercomplex (TBCD/α/TBCD/β). Discharge of the native α/β heterodimer occurs via interaction of the supercomplex with TBCC, which results in the triggering of TBC-bound β-tubulin-bound (E-site) GTP hydrolysis. This reaction acts as a switch for disassembly of the supercomplex and the release of GDP-bound heterodimer, which becomes polymerization competent following spontaneous E-site exchange with GTP. The tubulin-specific chaperones thus function together as a tubulin assembly machine, marrying the α- and β-tubulin subunits into a tightly associated heterodimer. The existence of this evolutionarily conserved pathway explains why it has never proved possible to isolate α- or β-tubulin as stable independent entities in the absence of their cognate partners, and implies that each exists and is maintained in the heterodimer in a non-minimal energy state. Here we describe methods for the purification of recombinant TBC’s as biologically active proteins following their expression in a variety of host/vector systems. PMID:23973072

  19. Serological survey of Borrelia infection of dogs in Sapporo, Japan, where Borrelia garinii infection was previously detected

    PubMed Central

    UESAKA, Karin; MAEZAWA, Masaki; INOKUMA, Hisashi

    2015-01-01

    A serological survey of Borrelia infection of dogs was performed in Sapporo, Japan, where Borrelia garinii infection in dogs was detected in 2011. A total of 314 serum samples were collected from dogs that visited three animal hospitals in Sapporo from 2012 to 2014. The two-step evaluation method, involving screening ELISA followed by Western blot analysis, was used to detect antibodies against Borrelia species. A total of 34 samples were positive by ELISA. Among those 34 samples, 32 were positive for Borrelia spp. by Western blot. These findings suggest that the 32 dogs (10.2%) generated antibodies against Borrelia burgdorferi sensu lato, such as B. garinii or B. afzelii. Antibody positivity was 7.6% and 13.3% for dogs living in urban and rural areas, respectively. Dogs with a history of tick infestation showed a positive rate of 16.7%, which was higher, although not significantly, than the 6.7% among dogs without a history. PMID:26522809

  20. Serological survey of Borrelia infection of dogs in Sapporo, Japan, where Borrelia garinii infection was previously detected.

    PubMed

    Uesaka, Karin; Maezawa, Masaki; Inokuma, Hisashi

    2016-04-01

    A serological survey of Borrelia infection of dogs was performed in Sapporo, Japan, where Borrelia garinii infection in dogs was detected in 2011. A total of 314 serum samples were collected from dogs that visited three animal hospitals in Sapporo from 2012 to 2014. The two-step evaluation method, involving screening ELISA followed by Western blot analysis, was used to detect antibodies against Borrelia species. A total of 34 samples were positive by ELISA. Among those 34 samples, 32 were positive for Borrelia spp. by Western blot. These findings suggest that the 32 dogs (10.2%) generated antibodies against Borrelia burgdorferi sensu lato, such as B. garinii or B. afzelii. Antibody positivity was 7.6% and 13.3% for dogs living in urban and rural areas, respectively. Dogs with a history of tick infestation showed a positive rate of 16.7%, which was higher, although not significantly, than the 6.7% among dogs without a history. PMID:26522809

  1. New Targets for Renal Interstitial Fibrosis: Relaxin Family Peptide Receptor 1 - Angiotensin Type 2 Receptor Heterodimers

    PubMed Central

    Sasser, Jennifer M.

    2014-01-01

    Recent findings have shown that relaxin has potent anti-fibrotic effects within the kidney; however, the signal transduction mechanisms involved in the renoprotective effects of relaxin are not well understood. Chow et al demonstrate that the relaxin receptor, RXFP1, forms heterodimer complexes with the angiotensin type 2 receptor, AT2, even in the absence of ligand and that these heterodimer complexes are required for relaxin’s antifibrotic effects. These findings identify a previously unknown link between relaxin and angiotensin II signaling that could be a potential new target for slowing the progression of fibrotic renal diseases. PMID:24978374

  2. New targets for renal interstitial fibrosis: relaxin family peptide receptor 1-angiotensin type 2 receptor heterodimers.

    PubMed

    Sasser, Jennifer M

    2014-07-01

    The signal transduction mechanisms involved in the renoprotective effects of relaxin are not well understood. Chow et al. demonstrate that relaxin family peptide receptor 1 (RXFP1) forms heterodimer complexes with the angiotensin type 2 receptor (AT2), even in the absence of ligand, and that these heterodimers are required for relaxin's antifibrotic effects. These findings identify a previously unknown link between relaxin and angiotensin II signaling that could be a potential new target for slowing the progression of fibrotic renal diseases. PMID:24978374

  3. Rickettsiae and Borrelia burgdorferi in ixodid ticks.

    PubMed Central

    Magnarelli, L A; Andreadis, T G; Stafford, K C; Holland, C J

    1991-01-01

    Nymphs and adults of hard-bodied ticks were collected in Connecticut and tested by direct and indirect immunofluorescence staining methods for rickettsiae and Borrelia burgdorferi. Of the 609 Ixodes dammini ticks examined, 59 (9.7%) harbored rickettsialike microorganisms in hemocytes (blood cells). These bacteria reacted with fluorescein-conjugated antiserum to Ehrlichia canis, the etiologic agent of with fluorescein-conjugated antiserum to Ehrlichia canis, the etiologic agent of canine ehrlichiosis. Prevalence of infection ranged from 6.8 to 12.7% for males and females, respectively. Although the specific identities of the hemocytic rickettsialike organisms are unknown, they share antigens with ehrlichiae. Electron microscopy revealed rickettsiae in ovarian tissues of I. dammini that also had infected hemocytes. Rickettsialike organisms were also observed in the hemocytes of 5 (6.9%) of 73 Dermacentor variabilis ticks. In analyses for B. burgdorferi, 146 (23.7%) of 617 I. dammini ticks harbored these spirochetes in midguts. Hemocytic rickettsialike microorganisms coexisted with B. burgdorferi in 36 (6.7%) of the 537 nymphs and adults of I. dammini examined. I. dammini, with its broad host range, has the potential to acquire multiple microorganisms. Images PMID:1757551

  4. Intrauterine transmission of Borrelia burgdorferi in dogs.

    PubMed

    Gustafson, J M; Burgess, E C; Wachal, M D; Steinberg, H

    1993-06-01

    To determine whether intrauterine transmission of Borrelia burgdorferi could exist in dogs, 10 female Beagles were inoculated intradermally with approximately 1,000 B burgdorferi on day 1 of proestrus; inoculation was repeated every 2 weeks during the gestation period. Ten female control Beagles were similarly inoculated with phosphate-buffered saline solution. Prior to the start of the study, all females and 3 males used for breeding were seronegative for B burgdorferi on the basis of results of the indirect fluorescent antibody test and immunoblot (western analysis. Similarly, results of culture of blood for B burgdorferi were negative. All 20 of the females were bred naturally. Blood samples were collected weekly for serologic testing and culture. Blood samples were obtained from live pups on day 1 of life, then weekly until pups were 6 weeks old when they were euthanatized. Tissues were obtained for culture and testing by use of polymerase chain reaction (PCR). Of 10 spirochete-inoculated (SI) females, 8 became infected with B burgdorferi as evidenced by spirochete culture results and/or PCR-detected B burgdorferi DNA in the tissues of females or their pups. Of the 10 SI females, 8 delivered litters (3 to 7 pups) that had at least 1 neonatal or 6-week-old pup with B burgdorferi DNA-positive tissues (by PCR), and spirochetes were cultured from tissues from pups of 2 litters.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8323057

  5. Adherence of Borrelia burgdorferi to granulocytes of different animal species.

    PubMed

    Grassmann, B; Kopp, P A; Schmitt, M; Blobel, H

    1997-04-01

    Adherence of 4 Borrelia (B.) burgdorferi strains (z7/22, z7/27, z7/41, PBi) to polymorphonuclear granulocytes from different domestic animals (horses, cattle, sheep, dogs) was investigated. All 4 strains adhered to the granulocytes. Binding assays indicated that the adherence occurred between structures on the surface of the borreliae ("binding-sites") and on the membranes of the granulocytes ("receptors"). The "receptors" consisted of 4 fractions (A, B, C, and D) with components differing in molecular weight (MW) and binding activity for proteins on the surface of B. burgdorferi. Fraction A (MW 80000) had the highest binding activity for B. burgdorferi. PMID:9144911

  6. Renal lesions associated with Borrelia burgdorferi infection in a dog.

    PubMed

    Grauer, G F; Burgess, E C; Cooley, A J; Hagee, J H

    1988-07-15

    Borrelia burgdorferi infection was diagnosed serologically in a dog with lethargy, stiffness, and anorexia. Treatment with ampicillin and chloramphenicol did not alleviate the signs. Azotemia, proteinuria, cylindruria, pyuria, and hematuria developed over a 3-month period. Antibody titer for B burgdorferi remained high (1:8,192) during this time. Renal histopathologic findings included severe, chronic, diffuse, membranoproliferative glomerulonephritis and moderate chronic, multifocal, interstitial nephritis. Borrelia burgdorferi organisms were identified in renal tissue and in urine by results of immunofluorescent studies and bacteriologic culture, respectively. PMID:3403355

  7. Blackbirds Turdus merula as competent reservoirs for Borrelia turdi and Borrelia valaisiana in Portugal: evidence from a xenodiagnostic experiment.

    PubMed

    Norte, Ana C; Lopes de Carvalho, Isabel; Núncio, Maria S; Ramos, Jaime A; Gern, Lise

    2013-08-01

    To confirm that thrushes, such as blackbirds Turdus merula, play a role as reservoir for some Borrelia genospecies, we performed a xenodiagnostic experiment with blackbirds captured in a mixed wood located in Western Portugal where Borrelia turdi, an uncommon genospecies in Europe, was the most prevalent genospecies associated with birds. Two out of five birds harboured B. turdi infected Ixodes frontalis at the time of capture. Four out of five birds transmitted spirochaetes to Ixodes ricinus xenodiagnostic ticks: two birds transmitted Borrelia valaisiana to 25.7% and 10.5% of ticks, and two transmitted B. turdi to 6.4% and 5.4% of ticks. Our results showed that blackbirds transmit B. valaisiana and B. turdi to I. ricinus feeding larvae, acting as reservoir hosts for these genospecies in nature. PMID:23864576

  8. Subunit-selective mutagenesis indicates minimal polymerase activity in heterodimer-associated p51 HIV-1 reverse transcriptase.

    PubMed

    Le Grice, S F; Naas, T; Wohlgensinger, B; Schatz, O

    1991-12-01

    We have purified and determined functional parameters of reconstituted, recombinant HIV-1 reverse transcriptase (RT) heterodimers within which either the p66 or p51 polypeptide was selectively mutated in one or both aspartic acid residues constituting the proposed polymerase active site (-Y-M-D-D-). Heterodimers containing a mutated p51 polypeptide retain almost wild type levels of both RNA-dependent DNA polymerase and ribonuclease H (RNaseH) activity. In contrast, heterodimers whose p66 polypeptide was likewise mutated exhibit wild type RNaseH activity but are deficient in RNA-dependent DNA polymerase activity. These results indicate that in heterodimer RT, the p51 component cannot compensate for active site mutations eliminating the activity of p66, indirectly implying that solely the p66 aspartic acid residues of heterodimer are crucial for catalysis. PMID:1718745

  9. Function of a p24 Heterodimer in Morphogenesis and Protein Transport in Penicillium oxalicum

    PubMed Central

    Wang, Fangzhong; Liu, Kuimei; Han, Lijuan; Jiang, Baojie; Wang, Mingyu; Fang, Xu

    2015-01-01

    The lignocellulose degradation capacity of filamentous fungi has been widely studied because of their cellulase hypersecretion. The p24 proteins in eukaryotes serve important functions in this secretory pathway. However, little is known about the functions of the p24 proteins in filamentous fungi. In this study, four p24 proteins were identified in Penicillium oxalicum. Six p24 double-deletion strains were constructed, and further studies were carried out with the ΔerpΔpδ strain. The experimental results suggested that Erp and Pδ form a p24 heterodimer in vivo. This p24 heterodimer participates in important morphogenetic events, including sporulation, hyphal growth, and lateral branching. The results suggested that the p24 heterodimer mediates protein transport, particularly that of cellobiohydrolase. Analysis of the intracellular proteome revealed that the ΔerpΔpδ double mutant is under secretion stress due to attempts to remove proteins that are jammed in the endomembrane system. These results suggest that the p24 heterodimer participates in morphogenesis and protein transport. Compared with P. oxalicum Δerp, a greater number of cellular physiological pathways were impaired in ΔerpΔpδ. This finding may provide new insights into the secretory pathways of filamentous fungi. PMID:26149342

  10. Tomato y-glutamilhydrolases: expression, characterization, and evidence for heterodimer formation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It is known that GGH is active as a dimmer and that plants can have several GGH genes whose homodimeric products differ functionally. However, it is not known whether GGH dimers dissociate under in-vivo conditions, whether heterodimers form, or how heterodimerization impacts enzyme activity. These i...

  11. Quantitative Analysis of HER2-mediated Effects on HER2 and Epidermal Growth Factor Receptor Endocytosis: DISTRIBUTION OF HOMO- AND HETERODIMERS DEPENDS ON RELATIVE HER2 LEVELS

    SciTech Connect

    Hendriks, Bart S.; Opresko, Lee ); Wiley, H Steven ); Lauffenburger, Douglas A.

    2003-05-15

    Endocytic trafficking plays an important role in the regulation of the epidermal growth factor receptor (EGFR) family. Many cell types express multiple EGFR family members (including EGFR, HER2, HER3 and/or HER4) that interact to form an array of homo- and hetero-dimers. Differential trafficking of these receptors should strongly affect signaling through this system by changing substrate access and heterodimerization efficiency. Because of the complexity of these dynamic processes we used a quantitative, computational model to understand this system. As a test case, parameters characterizing EGFR and HER2 interactions were derived using experimental data obtained from mammary epithelial cells constructed to express different levels of HER2. With this data we were able to estimate receptor-specific internalization rate constants and dimer uncoupling rate constants. These parameters were not otherwise experimentally accessible due to the complex system interplay. Our models indicated that HER2:EGFR heterodimers traffic as single entities. Direct experiments using EGF and anti-HER2 and anti-EGFR antibodies using independently derived cell lines confirmed many of the predictions of the model. Furthermore, our model could predict the relationship between HER2 expression levels and the transient distribution of EGFR homodimers and heterodimers. Our results suggest that the levels of HER2 found on normal cells are barely at the threshold necessary to drive efficient heterodimerization. Thus, altering local HER2 concentrations in membrane microdomains could serve as an effective mechanism for regulating HER2 heterodimerization and could explain why HER2 overexpression found in some cancers have such a profound effect on cell physiology.

  12. Structural and spectropotentiometric analysis of Blastochloris viridis heterodimer mutant reaction center

    SciTech Connect

    Ponomarenko, Nina S.; Li, Liang; Marino, Antony R.; Tereshko, Valentina; Ostafin, Agnes; Popova, Julia A.; Bylina, Edward J.; Ismagilov, Rustem F.; Norris, Jr., James R.

    2010-07-22

    Heterodimer mutant reaction centers (RCs) of Blastochloris viridis were crystallized using microfluidic technology. In this mutant, a leucine residue replaced the histidine residue which had acted as a fifth ligand to the bacteriochlorophyll (BChl) of the primary electron donor dimer M site (HisM200). With the loss of the histidine-coordinated Mg, one bacteriochlorophyll of the special pair was converted into a bacteriopheophytin (BPhe), and the primary donor became a heterodimer supermolecule. The crystals had dimensions 400 x 100 x 100 {micro}m, belonged to space group P4{sub 3}2{sub 1}2, and were isomorphous to the ones reported earlier for the wild type (WT) strain. The structure was solved to a 2.5 {angstrom} resolution limit. Electron-density maps confirmed the replacement of the histidine residue and the absence of Mg. Structural changes in the heterodimer mutant RC relative to the WT included the absence of the water molecule that is typically positioned between the M side of the primary donor and the accessory BChl, a slight shift in the position of amino acids surrounding the site of the mutation, and the rotation of the M194 phenylalanine. The cytochrome subunit was anchored similarly as in the WT and had no detectable changes in its overall position. The highly conserved tyrosine L162, located between the primary donor and the highest potential heme C{sub 380}, revealed only a minor deviation of its hydroxyl group. Concomitantly to modification of the BChl molecule, the redox potential of the heterodimer primary donor increased relative to that of the WT organism (772 mV vs. 517 mV). The availability of this heterodimer mutant and its crystal structure provides opportunities for investigating changes in light-induced electron transfer that reflect differences in redox cascades.

  13. Tomato gamma-glutamylhydrolases: expression, characterization, and evidence for heterodimer formation.

    PubMed

    Akhtar, Tariq A; McQuinn, Ryan P; Naponelli, Valeria; Gregory, Jesse F; Giovannoni, James J; Hanson, Andrew D

    2008-10-01

    Folates typically have gamma-linked polyglutamyl tails that make them better enzyme substrates and worse transport substrates than the unglutamylated forms. The tail can be shortened or removed by the vacuolar enzyme gamma-glutamyl hydrolase (GGH). It is known that GGH is active only as a dimer and that plants can have several GGH genes whose homodimeric products differ functionally. However, it is not known whether GGH dimers dissociate under in vivo conditions, whether heterodimers form, or how heterodimerization impacts enzyme activity. These issues were explored using the GGH system of tomato (Solanum lycopersicum). Tomato has three GGH genes that, like those in other eudicots, apparently diverged recently. LeGGH1 and LeGGH2 are expressed in fruit and all other organs, whereas LeGGH3 is expressed mainly in flower buds. LeGGH1 and LeGGH2 homodimers differ in bond cleavage preference; the LeGGH3 homodimer is catalytically inactive. Homodimers did not dissociate in physiological conditions. When coexpressed in Escherichia coli, LeGGH1 and LeGGH2 formed heterodimers with an intermediate bond cleavage preference, whereas LeGGH3 formed heterodimers with LeGGH1 or LeGGH2 that had one-half the activity of the matching homodimer. E. coli cells expressing LeGGH2 showed approximately 85% reduction in folate polyglutamates, but cells expressing LeGGH3 did not, confirming that LeGGH2 can function in vivo and LeGGH3 cannot. The formation of LeGGH1-LeGGH2 heterodimers was demonstrated in planta using bimolecular fluorescence complementation. Plant GGH heterodimers thus appear to form wherever different GGH genes are expressed simultaneously and to have catalytic characteristics midway between those of the corresponding homodimers. PMID:18757550

  14. Borrelia burgdorferi visualized in Ixodes scapularis tick excrement by immunofluorescence.

    PubMed

    Patton, Toni G; Brandt, Kevin S; Gilmore, Robert D

    2012-11-01

    The enzootic cycle of Borrelia burgdorferi, the etiologic agent of Lyme disease, involves Ixodes spp. ticks and vertebrates. Resident tick Borrelia, harbored inside the midgut, are eventually expelled with the tick's saliva into the vertebrate host when a tick consumes a blood meal. During this 4- to 5-day feeding period I. scapularis will defecate onto the host's skin. Previously we detected borrelial DNA in tick feces throughout engorgement. In this study we report the microscopic examination for B. burgdorferi in nymphal excrement. Using immunofluorescence assays, we observed Borrelia in all mouse skin and capsule fecal swabs tested, although we could not culture the spirochetes. These results update our previous analysis by revealing that spirochetes can also be visualized in tick excrement. Furthermore, the results emphasize that borrelial contamination by defecation is a possibility, and that caution should be exercised by researchers investigating pathogen/host/vector interactions. The biological significance of the presence of non-culturable Borrelia in tick feces during engorgement is unclear. PMID:22651382

  15. Geographic Differences in Genetic Locus Linkages for Borrelia burgdorferi

    PubMed Central

    Travinsky, Bridgit; Bunikis, Jonas

    2010-01-01

    Borrelia burdorferi genotype in the northeastern United States is associated with Lyme borreliosis severity. Analysis of DNA sequences of the outer surface protein C gene and rrs-rrlA intergenic spacer from extracts of Ixodes spp. ticks in 3 US regions showed linkage disequilibrium between the 2 loci within a region but not consistently between regions. PMID:20587192

  16. Borrelia miyamotoi–Associated Neuroborreliosis in Immunocompromised Person

    PubMed Central

    Lobenstein, Sabine; Hermann, Beate; Margos, Gabriele; Fingerle, Volker

    2016-01-01

    Borrelia miyamotoi is a newly recognized human pathogen in the relapsing fever group of spirochetes. We investigated a case of B. miyamotoi infection of the central nervous system resembling B. burgdorferi–induced Lyme neuroborreliosis and determined that this emergent agent of central nervous system infection can be diagnosed with existing methods. PMID:27533748

  17. Borrelia burgdorferi Infection and Cutaneous Lyme Disease, Mexico

    PubMed Central

    Gordillo-Pérez, Guadalupe; Torres, Javier; Solórzano-Santos, Fortino; de Martino, Sylvie; Lipsker, Dan; Velázquez, Edmundo; Ramon, Guillermo; Onofre, Muñoz; Jaulhac, Benoit

    2007-01-01

    Four patients who had received tick bites while visiting forests in Mexico had skin lesions that met the case definition of erythema migrans, or borrelial lymphocytoma. Clinical diagnosis was supported with histologic, serologic, and molecular tests. This study suggests the Borrelia burgdorferi infection is in Mexico. PMID:18258006

  18. Borrelia miyamotoi-Associated Neuroborreliosis in Immunocompromised Person.

    PubMed

    Boden, Katharina; Lobenstein, Sabine; Hermann, Beate; Margos, Gabriele; Fingerle, Volker

    2016-09-01

    Borrelia miyamotoi is a newly recognized human pathogen in the relapsing fever group of spirochetes. We investigated a case of B. miyamotoi infection of the central nervous system resembling B. burgdorferi-induced Lyme neuroborreliosis and determined that this emergent agent of central nervous system infection can be diagnosed with existing methods. PMID:27533748

  19. Ménage à trois: Borrelia, dendritic cells, and tick saliva interactions.

    PubMed

    Mason, Lauren M K; Veerman, Christiaan C; Geijtenbeek, Teunis B H; Hovius, Joppe W R

    2014-02-01

    Borrelia burgdorferi sensu lato, the causative agent of Lyme borreliosis, is inoculated into the skin during an Ixodes tick bite where it is recognised and captured by dendritic cells (DCs). However, considering the propensity of Borrelia to disseminate, it would appear that DCs fall short in mounting a robust immune response against it. Many aspects of the DC-driven immune response to Borrelia have been examined. Recently, components of tick saliva have been identified that sabotage DC responses and aid Borrelia infection. In this review, we summarise what is currently known about the immune response of DCs to Borrelia and explore the mechanisms by which Borrelia manages to circumvent this immune response, with or without the help of tick salivary proteins. PMID:24388562

  20. Whole genome sequence of an unusual Borrelia burgdorferi sensu lato isolate

    SciTech Connect

    Casjens, S.R.; Dunn, J.; Fraser-Liggett, C. M.; Mongodin, E. F.; Qiu, W. G.; Luft, B. J.; Schutzer, S. E.

    2011-03-01

    Human Lyme disease is caused by a number of related Borrelia burgdorferi sensu lato species. We report here the complete genome sequence of Borrelia sp. isolate SV1 from Finland. This isolate is to date the closest known relative of B. burgdorferi sensu stricto, but it is sufficiently genetically distinct from that species that it and its close relatives warrant its candidacy for new-species status. We suggest that this isolate should be named 'Borrelia finlandensis.'

  1. Fano resonance assisting plasmonic circular dichroism from nanorice heterodimers for extrinsic chirality

    PubMed Central

    Hu, Li; Huang, Yingzhou; Fang, Liang; Chen, Guo; Wei, Hua; Fang, Yurui

    2015-01-01

    In this work, the circular dichroisms (CD) of nanorice heterodimers consisting of two parallel arranged nanorices with the same size but different materials are investigated theoretically. Symmetry-breaking is introduced by using different materials and oblique incidence to achieve strong CD at the vicinity of Fano resonance peaks. We demonstrate that all Au-Ag heterodimers exhibit multipolar Fano resonances and strong CD effect. A simple quantitative analysis shows that the structure with larger Fano asymmetry factor has stronger CD. The intensity and peak positions of the CD effect can be flexibly tuned in a large range by changing particle size, shape, the inter-particle distance and surroundings. Furthermore, CD spectra exhibit high sensitivity to ambient medium in visible and near infrared regions. Our results here are beneficial for the design and application of high sensitive CD sensors and other related fields. PMID:26538460

  2. Heterodimer of two distinguishable atoms in a one-dimensional optical lattice

    SciTech Connect

    Odong, Otim; Sanders, Jerome C.; Javanainen, Juha

    2011-09-15

    Within the Bose-Hubbard model, we theoretically determine the stationary states of two distinguishable atoms in a one-dimensional optical lattice and compare with the case of two identical bosons. A heterodimer has odd-parity dissociated states that do not depend on the interactions between the atoms, and the lattice momenta of the two atomic species may have different averages even for a bound state of the dimer. We discuss methods to detect the dimer. The different distributions of the quasimomenta of the two species may be observed in suitable time-of-flight experiments. Also, an asymmetry in the lineshape as a function of the modulation frequency may reveal the presence of the odd-parity dissociated states when a heterodimer is dissociated by modulating the depth of the optical lattice.

  3. Transcriptional activation by heterodimers of the achaete-scute and daughterless gene products of Drosophila.

    PubMed Central

    Cabrera, C V; Alonso, M C

    1991-01-01

    The achaete-scute complex (AS-C) and the daughterless (da) genes encode helix-loop-helix proteins which have been shown to interact in vivo and to be required for neurogenesis. We show in vitro that heterodimers of three AS-C products with DA bind DNA strongly, whereas DA homodimers bind weakly and homo or heterocombinations of AS-C products not at all. Proteins unable to dimerize did not bind DNA. Target sequences for the heterodimers were found in the promoters of the hunchback and the achaete genes. Using sequences of the former we show that the DNA binding results obtained in vitro fully correlate with the ability of different combinations to activate the expression of a reporter gene in yeast. Embryos deficient for the lethal of scute gene fail to activate hunchback in some neural lineages in a pattern consistent with the lack of a member of a multigene family. Images PMID:1915272

  4. Characterization of disulfide-linked heterodimers containing apolipoprotein D in human plasma lipoproteins.

    PubMed

    Blanco-Vaca, F; Via, D P; Yang, C Y; Massey, J B; Pownall, H J

    1992-12-01

    Human plasma apolipoprotein (apo) D is a glycoprotein with an apparent molecular weight of 29,000 M(r). It is present, mainly, in high density lipoproteins (HDL) and very high density lipoproteins (VHDL). Western blot analysis of HDL and VHDL using rabbit antibodies to human apoD revealed major immunoreactive bands at 29,000 and 38,000 M(r), with minor bands ranging from 50,000 to and 80,000 M(r). Only the 29,000 M(r) band corresponding to apoD remained when the electrophoresis was conducted under reducing conditions, demonstrating that apoD is cross-linked to other proteins via disulfide bonds. The broad pattern of immunoreactivity was also observed under nonreducing conditions when the blood was collected into a solution of sulfhydryl-trapping reagents, or when these reagents were added to the isolated lipoproteins. These results indicated that the disulfide bonds were not the result of disulfide exchange during the experimental procedures. On the basis of amino acid sequencing and reactions to antibodies, the 38,000 M(r) band was identified as an apoD-apoA-II heterodimer. The apoD-apoA-II was also demonstrated in plasma. In both HDL and plasma, the apoD-apoA-II heterodimer constituted the major form of apoD. Disulfide-linked heterodimers of apoD and apoB-100 were also found in low and very low density lipoproteins, and in whole plasma. It is concluded that a fraction of human apoD, like other cysteine-containing apolipoproteins, exists as a disulfide-linked heterodimer with other apolipoproteins in all major human lipoprotein fractions. PMID:1479288

  5. Solution structure of the isolated histone H2A-H2B heterodimer.

    PubMed

    Moriwaki, Yoshihito; Yamane, Tsutomu; Ohtomo, Hideaki; Ikeguchi, Mitsunori; Kurita, Jun-Ichi; Sato, Masahiko; Nagadoi, Aritaka; Shimojo, Hideaki; Nishimura, Yoshifumi

    2016-01-01

    During chromatin-regulated processes, the histone H2A-H2B heterodimer functions dynamically in and out of the nucleosome. Although detailed crystal structures of nucleosomes have been established, that of the isolated full-length H2A-H2B heterodimer has remained elusive. Here, we have determined the solution structure of human H2A-H2B by NMR coupled with CS-Rosetta. H2A and H2B each contain a histone fold, comprising four α-helices and two β-strands (α1-β1-α2-β2-α3-αC), together with the long disordered N- and C-terminal H2A tails and the long N-terminal H2B tail. The N-terminal αN helix, C-terminal β3 strand, and 310 helix of H2A observed in the H2A-H2B nucleosome structure are disordered in isolated H2A-H2B. In addition, the H2A α1 and H2B αC helices are not well fixed in the heterodimer, and the H2A and H2B tails are not completely random coils. Comparison of hydrogen-deuterium exchange, fast hydrogen exchange, and {(1)H}-(15)N hetero-nuclear NOE data with the CS-Rosetta structure indicates that there is some conformation in the H2A 310 helical and H2B Lys11 regions, while the repression domain of H2B (residues 27-34) exhibits an extended string-like structure. This first structure of the isolated H2A-H2B heterodimer provides insight into its dynamic functions in chromatin. PMID:27181506

  6. Proton transfer in histidine-tryptophan heterodimers embedded in helium droplets

    NASA Astrophysics Data System (ADS)

    Bellina, Bruno; Merthe, Daniel J.; Kresin, Vitaly V.

    2015-03-01

    We used cold helium droplets as nano-scale reactors to form and ionize, by electron bombardment and charge transfer, aromatic amino acid heterodimers of histidine with tryptophan, methyl-tryptophan, and indole. The molecular interaction occurring through an N-H ṡ ṡ ṡ N hydrogen bond leads to a proton transfer from the indole group of tryptophan to the imidazole group of histidine in a radical cationic environment.

  7. Quantum Dot–Bridge–Fullerene Heterodimers with Controlled Photoinduced Electron Transfer

    SciTech Connect

    Cotlet, M.; Xu, Z.

    2011-06-27

    A series of donor-bridge-acceptor systems in the form of core/shell CdSe/ZnS quantum dot-bridge-fullerene heterodimers (see picture) with varying bridge length and varying quantum dot size were self-assembled by a surface-based stepwise method to demonstrate control of the rate and of the magnitude of fluctuations of photoinduced electron transfer at the single-molecule level.

  8. Proton transfer in histidine-tryptophan heterodimers embedded in helium droplets

    SciTech Connect

    Bellina, Bruno; Merthe, Daniel J.; Kresin, Vitaly V.

    2015-03-21

    We used cold helium droplets as nano-scale reactors to form and ionize, by electron bombardment and charge transfer, aromatic amino acid heterodimers of histidine with tryptophan, methyl-tryptophan, and indole. The molecular interaction occurring through an N–H ⋅ ⋅ ⋅ N hydrogen bond leads to a proton transfer from the indole group of tryptophan to the imidazole group of histidine in a radical cationic environment.

  9. Solution structure of the isolated histone H2A-H2B heterodimer

    PubMed Central

    Moriwaki, Yoshihito; Yamane, Tsutomu; Ohtomo, Hideaki; Ikeguchi, Mitsunori; Kurita, Jun-ichi; Sato, Masahiko; Nagadoi, Aritaka; Shimojo, Hideaki; Nishimura, Yoshifumi

    2016-01-01

    During chromatin-regulated processes, the histone H2A-H2B heterodimer functions dynamically in and out of the nucleosome. Although detailed crystal structures of nucleosomes have been established, that of the isolated full-length H2A-H2B heterodimer has remained elusive. Here, we have determined the solution structure of human H2A-H2B by NMR coupled with CS-Rosetta. H2A and H2B each contain a histone fold, comprising four α-helices and two β-strands (α1–β1–α2–β2–α3–αC), together with the long disordered N- and C-terminal H2A tails and the long N-terminal H2B tail. The N-terminal αN helix, C-terminal β3 strand, and 310 helix of H2A observed in the H2A-H2B nucleosome structure are disordered in isolated H2A-H2B. In addition, the H2A α1 and H2B αC helices are not well fixed in the heterodimer, and the H2A and H2B tails are not completely random coils. Comparison of hydrogen-deuterium exchange, fast hydrogen exchange, and {1H}-15N hetero-nuclear NOE data with the CS-Rosetta structure indicates that there is some conformation in the H2A 310 helical and H2B Lys11 regions, while the repression domain of H2B (residues 27–34) exhibits an extended string-like structure. This first structure of the isolated H2A-H2B heterodimer provides insight into its dynamic functions in chromatin. PMID:27181506

  10. Plasmon-mediated binding forces on gold or silver homodimer and heterodimer

    NASA Astrophysics Data System (ADS)

    Liaw, Jiunn-Woei; Kuo, Ting-Yu; Kuo, Mao-Kuen

    2016-02-01

    This study theoretically investigates plasmon-mediated optical binding forces, which are exerted on metal homo or heterodimers, induced by the normal illumination of a linearly polarized plane wave or Gaussian beam. Using the multiple multipole method, we analyzed the optical force in terms of Maxwell's stress tensor for various interparticle distance at some specific wavelengths. Numerical results show that for a given wavelength there are several stable equilibrium distances between two nanoparticles (NPs) of a homodimer, which are slightly shorter than some integer multiples of the wavelength in medium, such that metal dimer acts as bonded together. At these specific interparticle distances, the optical force between dimer is null and serves a restoring force, which is repulsive and attractive, respectively, as the two NPs are moving closer to and away from each other. The spring constant of the restoring force at the first stable equilibrium is always the largest, indicating that the first stable equilibrium distance is the most stable one. Moreover, the central line (orientation) of a dimer tends to be perpendicular to the polarization of light. For the cases of heterodimers, the phenomenon of stable equilibrium interparticle distance still exists, except there is an extra net photophoretic force drifting the heterodimer as one. Moreover, gradient force provided by a Gaussian beam may reduce the stability of these equilibriums, so larger NPs are preferred to stabilize a dimer under illumination of Gaussian beam. The finding may pave the way for using optical manipulation on the gold or silver colloidal self-assembly.

  11. Binary Toxin Subunits of Lysinibacillus sphaericus Are Monomeric and Form Heterodimers after In Vitro Activation

    PubMed Central

    Choong, Yeu Khai; Torres, Jaume; Boonserm, Panadda

    2016-01-01

    The binary toxin from Lysinibacillus sphaericus has been successfully used for controlling mosquito-transmitted diseases. An activation step shortens both subunits BinA and BinB before their interaction with membranes and internalization in midgut cells, but the precise role of this activation step is unknown. Herein, we show conclusively using three orthogonal biophysical techniques that protoxin subunits form only monomers in aqueous solution. However, in vitro activated toxins readily form heterodimers. This oligomeric state did not change after incubation of these heterodimers with detergent. These results are consistent with the evidence that maximal toxicity in mosquito larvae is achieved when the two subunits, BinA and BinB, are in a 1:1 molar ratio, and directly link proteolytic activation to heterodimerization. Formation of a heterodimer must thus be necessary for subsequent steps, e.g., interaction with membranes, or with a suitable receptor in susceptible mosquito species. Lastly, despite existing similarities between BinB C-terminal domain with domains 3 and 4 of pore-forming aerolysin, no aerolysin-like SDS-resistant heptameric oligomers were observed when the activated Bin subunits were incubated in the presence of detergents or lipidic membranes. PMID:27341696

  12. Cy3-Cy5 Covalent Heterodimers for Single-Molecule Photoswitching

    PubMed Central

    Conley, Nicholas R.; Biteen, Julie S.; Moerner, W. E.

    2009-01-01

    Covalent heterodimers of the Cy3 and Cy5 fluorophores have been prepared from commercially available starting materials and characterized at the single-molecule level. This system behaves as a discrete molecular photoswitch, in which photoexcitation of the Cy5 results in fluorescence emission or, with a much lower probability, causes the Cy5 to enter into a long-lived, but metastable, dark state. Photoinduced recovery of the emissive Cy5 is achieved by very low intensity excitation (5 W cm−2) of the Cy3 fluorophore at a shorter wavelength. A similar system consisting of proximal, but not covalently linked, Cy3 and Cy5 has found application in stochastic optical reconstruction microscopy (STORM), a single-molecule localization-based technique for super-resolution imaging that requires photoswitching. The covalent Cy3-Cy5 heterodimers described herein eliminate the need for probabilistic methods of situating the Cy3 and Cy5 in close proximity to enable photoswitching. As proof of principle, these heterodimers have been applied to super-resolution imaging of the tubular stalk structures of live Caulobacter crescentus bacterial cells. PMID:18754575

  13. Cy3-Cy5 covalent heterodimers for single-molecule photoswitching.

    PubMed

    Conley, Nicholas R; Biteen, Julie S; Moerner, W E

    2008-09-25

    Covalent heterodimers of the Cy3 and Cy5 fluorophores have been prepared from commercially available starting materials and characterized at the single-molecule level. This system behaves as a discrete molecular photoswitch, in which photoexcitation of the Cy5 results in fluorescence emission or, with a much lower probability, causes the Cy5 to enter into a long-lived, but metastable, dark state. Photoinduced recovery of the emissive Cy5 is achieved by very low intensity excitation (5 W cm(-2)) of the Cy3 fluorophore at a shorter wavelength. A similar system consisting of proximal, but not covalently linked, Cy3 and Cy5 has found application in stochastic optical reconstruction microscopy (STORM), a single-molecule localization-based technique for super-resolution imaging that requires photoswitching. The covalent Cy3-Cy5 heterodimers described herein eliminate the need for probabilistic methods of situating the Cy3 and Cy5 in close proximity to enable photoswitching. As proof of principle, these heterodimers have been applied to super-resolution imaging of the tubular stalk structures of live Caulobacter crescentus bacterial cells. PMID:18754575

  14. Catalytic Asymmetric Synthesis of Ketene Heterodimer β-Lactones: Scope and Limitations.

    PubMed

    Chen, Shi; Ibrahim, Ahmad A; Peraino, Nicholas J; Nalla, Divya; Mondal, Mukulesh; Van Raaphorst, Maxwell; Kerrigan, Nessan J

    2016-09-01

    In this article we describe extensive studies of the catalytic asymmetric heterodimerization of ketenes to give ketene heterodimer β-lactones. The optimal catalytic system was determined to be a cinchona alkaloid derivative (TMS-quinine or Me-quinidine). The desired ketene heterodimer β-lactones were obtained in good to excellent yields (up to 90%), with excellent levels of enantioselectivity (≥90% ee for 33 Z and E isomer examples), good to excellent (Z)-olefin isomer selectivity (≥90:10 for 20 examples), and excellent regioselectivity (only one regioisomer formed). Full details of catalyst development studies, catalyst loading investigations, substrate scope exploration, protocol innovations (including double in situ ketene generation for 7 examples), and an application to a cinnabaramide A intermediate are described. The addition of lithium perchlorate (1-2 equiv) as an additive to the alkaloid catalyst system was found to favor formation of the E isomer of the ketene heterodimer. Ten examples were formed with moderate to excellent (E)-olefin isomer selectivity (74:25 to 97:3) and with excellent enantioselectivity (84-98% ee). PMID:27490092

  15. Interaction between Borrelia burgdorferi and endothelium in vitro.

    PubMed

    Szczepanski, A; Furie, M B; Benach, J L; Lane, B P; Fleit, H B

    1990-05-01

    During the pathogenesis of Lyme disease, Borrelia burgdorferi spreads hematogenously from the site of a tick bite to several tissues throughout the body. The specific mechanism of spirochete emigration is presently unknown. Using cultured human umbilical vein endothelial cells, we found that Borrelia burgdorferi bound to the endothelial cells and to the subendothelial matrix. Low passage isolates adhered 22-30-fold greater than a strain maintained in culture continuously. Spirochete binding to subendothelial matrix was inhibited 48-63% by pretreatment of the matrix with anti-fibronectin antiserum. Spirochete migration across endothelial monolayers cultured on amniotic membrane was increased when the monolayers were damaged by chemical or physical means. Electron microscopic examination of spirochete-endothelial interactions demonstrated the presence of spirochetes in the intercellular junctions between endothelial cells as well as beneath the monolayers. Scanning electron microscopy identified a mechanism of transendothelial migration whereby spirochetes pass between cells into the amniotic membrane at areas where subendothelium is exposed. PMID:2332509

  16. [Diagnostic aspects of Borrelia-infections in dogs].

    PubMed

    Hovius, K E; Houwers, D J

    2007-08-15

    This paper discusses the problem of diagnosing borreliosis (Lyme disease) in dogs. A prospective cohort study in the Kempen district, a known Borrelia focus in The Netherlands, showed that dogs with the presumptive symptoms of borreliosis, episodic malaise and lameness, had significantly higher and longer lasting anti-Borrelia IgG titers than asymptomatic dogs. A small part of these dogs also had antibodies directed against the IR6 (C6) antigen which indicates persistent active Borrelia infection. A few typical case histories are presented. Dogs with episodic malaise and lameness with persistent high IgG titers are suspect of suffering from borreliosis. IR6 antibodies make this diagnosis likely. Initially, such patients should be treated with doxycyclin (10 mg/kg 1dd) for 10 days. If the symptoms recurr within a few months, a longer treatment (eg 6 weeks) should be considered. Bernese mountain dogs were strongly over-represented among the borreliosis patients in the cohort study and most high titered samples among those submitted for--diagnostic--serology appear to come from this breed, which suggests that these dogs have difficulties with clearing this tick-borne infection. PMID:17849909

  17. An Invasive Mammal (the Gray Squirrel, Sciurus carolinensis) Commonly Hosts Diverse and Atypical Genotypes of the Zoonotic Pathogen Borrelia burgdorferi Sensu Lato

    PubMed Central

    Magierecka, Agnieszka; Gilbert, Lucy; Edoff, Alissa; Brereton, Amelia; Kilbride, Elizabeth; Denwood, Matt; Birtles, Richard; Biek, Roman

    2015-01-01

    Invasive vertebrate species can act as hosts for endemic pathogens and may alter pathogen community composition and dynamics. For the zoonotic pathogen Borrelia burgdorferi sensu lato, the agent of Lyme borreliosis, recent work shows invasive rodent species can be of high epidemiological importance and may support host-specific strains. This study examined the role of gray squirrels (Sciurus carolinensis) (n = 679), an invasive species in the United Kingdom, as B. burgdorferi sensu lato hosts. We found that gray squirrels were frequently infested with Ixodes ricinus, the main vector of B. burgdorferi sensu lato in the United Kingdom, and 11.9% were infected with B. burgdorferi sensu lato. All four genospecies that occur in the United Kingdom were detected in gray squirrels, and unexpectedly, the bird-associated genospecies Borrelia garinii was most common. The second most frequent infection was with Borrelia afzelii. Genotyping of B. garinii and B. afzelii produced no evidence for strains associated with gray squirrels. Generalized linear mixed models (GLMM) identified tick infestation and date of capture as significant factors associated with B. burgdorferi sensu lato infection in gray squirrels, with infection elevated in early summer in squirrels infested with ticks. Invasive gray squirrels appear to become infected with locally circulating strains of B. burgdorferi sensu lato, and further studies are required to determine their role in community disease dynamics. Our findings highlight the fact that the role of introduced host species in B. burgdorferi sensu lato epidemiology can be highly variable and thus difficult to predict. PMID:25888168

  18. Detection of Borrelia burgdorferi sensu stricto and Borrelia garinii DNAs in patient with Hyperkeratosis lenticularis perstans (Flegel disease).

    PubMed

    Schwarzova, Katarina; Kozub, Peter; Szep, Zoltan; Golovchenko, Marina; Rudenko, Natasha

    2016-09-01

    Determination of the causative agent of erythema-like skin lesions in case of nonspecific superficial perivascular dermatitis was supported by histological examination and led to the latter diagnosis of Hyperkeratosis lenticularis perstans (Flegel disease) in patient. The presence of antibodies against Borrelia burgdorferi in patient serum was confirmed by a routine ELISA method and verified by Western blot technique. Skin biopsy and blood specimens were analyzed by PCR and multilocus sequence analysis (MLSA). Western blot method revealed IgG antibody response against two specific antigens, 17 and 83 kDa proteins. The recombinant test detected IgG antibody response against p100 and p41 antigens. The sequence analysis of amplicons from the selected genomic loci obtained from skin biopsy and serum samples revealed the presence of two species from B. burgdorferi sensu lato complex as a co-infection in this patient-B. burgdorferi sensu stricto (s.s.) and Borrelia garinii. PMID:26769152

  19. Evidence of In Vivo Existence of Borrelia Biofilm in Borrelial Lymphocytomas

    PubMed Central

    Sapi, E.; Balasubramanian, K.; Poruri, A.; Maghsoudlou, J. S.; Socarras, K. M.; Timmaraju, A. V.; Filush, K. R.; Gupta, K.; Shaikh, S.; Theophilus, P. A. S.; Luecke, D. F.; MacDonald, A.; Zelger, B.

    2016-01-01

    Lyme borreliosis, caused by the spirochete Borrelia burgdorferi sensu lato, has grown into a major public health problem. We recently identified a novel morphological form of B. burgdorferi, called biofilm, a structure that is well known to be highly resistant to antibiotics. However, there is no evidence of the existence of Borrelia biofilm in vivo; therefore, the main goal of this study was to determine the presence of Borrelia biofilm in infected human skin tissues. Archived skin biopsy tissues from borrelial lymphocytomas (BL) were reexamined for the presence of B. burgdorferi sensu lato using Borrelia-specific immunohistochemical staining (IHC), fluorescent in situ hybridization, combined fluorescent in situ hybridization (FISH)–IHC, polymerase chain reaction (PCR), and fluorescent and atomic force microscopy methods. Our morphological and histological analyses showed that significant amounts of Borrelia-positive spirochetes and aggregates exist in the BL tissues. Analyzing structures positive for Borrelia showed that aggregates, but not spirochetes, expressed biofilm markers such as protective layers of different mucopolysaccharides, especially alginate. Atomic force microscopy revealed additional hallmark biofilm features of the Borrelia/alginate-positive aggregates such as inside channels and surface protrusions. In summary, this is the first study that demonstrates the presence of Borrelia biofilm in human infected skin tissues. PMID:27141311

  20. Evidence of In Vivo Existence of Borrelia Biofilm in Borrelial Lymphocytomas.

    PubMed

    Sapi, E; Balasubramanian, K; Poruri, A; Maghsoudlou, J S; Socarras, K M; Timmaraju, A V; Filush, K R; Gupta, K; Shaikh, S; Theophilus, P A S; Luecke, D F; MacDonald, A; Zelger, B

    2016-03-01

    Lyme borreliosis, caused by the spirochete Borrelia burgdorferi sensu lato, has grown into a major public health problem. We recently identified a novel morphological form of B. burgdorferi, called biofilm, a structure that is well known to be highly resistant to antibiotics. However, there is no evidence of the existence of Borrelia biofilm in vivo; therefore, the main goal of this study was to determine the presence of Borrelia biofilm in infected human skin tissues. Archived skin biopsy tissues from borrelial lymphocytomas (BL) were reexamined for the presence of B. burgdorferi sensu lato using Borrelia-specific immunohistochemical staining (IHC), fluorescent in situ hybridization, combined fluorescent in situ hybridization (FISH)-IHC, polymerase chain reaction (PCR), and fluorescent and atomic force microscopy methods. Our morphological and histological analyses showed that significant amounts of Borrelia-positive spirochetes and aggregates exist in the BL tissues. Analyzing structures positive for Borrelia showed that aggregates, but not spirochetes, expressed biofilm markers such as protective layers of different mucopolysaccharides, especially alginate. Atomic force microscopy revealed additional hallmark biofilm features of the Borrelia/alginate-positive aggregates such as inside channels and surface protrusions. In summary, this is the first study that demonstrates the presence of Borrelia biofilm in human infected skin tissues. PMID:27141311

  1. A boy with a tight skin: Borrelia-associated early-onset morphea.

    PubMed

    Verberkt, Roos M; Janssen, Matthijs; Wesseling, Judit

    2014-01-01

    We present a case of a 16-year-old boy with morphea caused by Borrelia burgdorferi. We re-emphasise an immunohistochemical method, focus floating microscopy (FFM), to detect Borrelia burgdorferi spirochetes in tissue sections. Focus floating microscopy (FFM) proved to be more sensitive than polymerase chain reaction (PCR) and nearly equally specific. PMID:24093617

  2. Borrelia burgdorferi sensu lato in humans in a rural area of Paraná State, Brazil

    PubMed Central

    Gonçalves, Daniela Dib; Moura, Rodrigo Assunção; Nunes, Mônica; Carreira, Teresa; Vidotto, Odilon; Freitas, Julio Cesar; Vieira, Maria Luísa

    2015-01-01

    This study describes the detection of Borrelia garinii and Borrelia burgdorferi sensu stricto (s.s.) in Brazilian individuals using PCR and DNA sequencing. Our results suggest that these species are emerging pathogens in this country, and additional studies are necessary to determine the epidemiological characteristics of this disease in Brazil. PMID:26273276

  3. Borrelia burgdorferi sensu lato in humans in a rural area of Paraná State, Brazil.

    PubMed

    Gonçalves, Daniela Dib; Moura, Rodrigo Assunção; Nunes, Mônica; Carreira, Teresa; Vidotto, Odilon; Freitas, Julio Cesar; Vieira, Maria Luísa

    2015-06-01

    This study describes the detection of Borrelia garinii and Borrelia burgdorferi sensu stricto (s.s.) in Brazilian individuals using PCR and DNA sequencing. Our results suggest that these species are emerging pathogens in this country, and additional studies are necessary to determine the epidemiological characteristics of this disease in Brazil. PMID:26273276

  4. Genome Sequence of Borrelia chilensis VA1, a South American Member of the Lyme Borreliosis Group

    PubMed Central

    Huang, Weihua; Ojaimi, Caroline; Fallon, John T.; Travisany, Dante; Maass, Alejandro; Ivanova, Larisa; Tomova, Alexandra; González-Acuña, Daniel; Cabello, Felipe C.

    2015-01-01

    Borrelia chilensis strain VA1 is a recently described South American member of the Borrelia burgdorferi sensu lato complex from Chile. Whole-genome sequencing analysis determined its linear chromosome and plasmids lp54 and cp26, confirmed its membership in the Lyme borreliosis group, and will open new research avenues regarding its pathogenic potential. PMID:25676758

  5. Cooperation of Doxycycline with Phytochemicals and Micronutrients Against Active and Persistent Forms of Borrelia sp

    PubMed Central

    Goc, Anna; Niedzwiecki, Alexandra; Rath, Matthias

    2016-01-01

    Phytochemicals and micronutrients represent a growing theme in antimicrobial defense; however, little is known about their anti-borreliae effects of reciprocal cooperation with antibiotics. A better understanding of this aspect could advance our knowledge and help improve the efficacy of current approaches towards Borrelia sp. In this study, phytochemicals and micronutrients such as baicalein, luteolin, 10-HAD, iodine, rosmarinic acid, and monolaurin, as well as, vitamins D3 and C were tested in a combinations with doxycycline for their in vitro effectiveness against vegetative (spirochetes) and latent (rounded bodies, biofilm) forms of Borrelia burgdorferi and Borrelia garinii. Anti-borreliae effects were evaluated according to checkerboard assays and supported by statistical analysis. The results showed that combination of doxycycline with flavones such as baicalein and luteolin exhibited additive effects against all morphological forms of studied Borrelia sp. Doxycycline combined with iodine demonstrated additive effects against spirochetes and biofilm, whereas with fatty acids such as monolaurin and 10-HAD it produced FICIs of indifference. Additive anti-spirochetal effects were also observed when doxycycline was used with rosmarinic acid and both vitamins D3 and C. Antagonism was not observed in any of the cases. This data revealed the intrinsic anti-borreliae activity of doxycycline with tested phytochemicals and micronutrients indicating that their addition may enhance efficacy of this antibiotic in combating Borrelia sp. Especially the addition of flavones balcalein and luteolin to a doxycycline regimen could be explored further in defining more effective treatments against these bacteria. PMID:27570483

  6. Cooperation of Doxycycline with Phytochemicals and Micronutrients Against Active and Persistent Forms of Borrelia sp.

    PubMed

    Goc, Anna; Niedzwiecki, Alexandra; Rath, Matthias

    2016-01-01

    Phytochemicals and micronutrients represent a growing theme in antimicrobial defense; however, little is known about their anti-borreliae effects of reciprocal cooperation with antibiotics. A better understanding of this aspect could advance our knowledge and help improve the efficacy of current approaches towards Borrelia sp. In this study, phytochemicals and micronutrients such as baicalein, luteolin, 10-HAD, iodine, rosmarinic acid, and monolaurin, as well as, vitamins D3 and C were tested in a combinations with doxycycline for their in vitro effectiveness against vegetative (spirochetes) and latent (rounded bodies, biofilm) forms of Borrelia burgdorferi and Borrelia garinii. Anti-borreliae effects were evaluated according to checkerboard assays and supported by statistical analysis. The results showed that combination of doxycycline with flavones such as baicalein and luteolin exhibited additive effects against all morphological forms of studied Borrelia sp. Doxycycline combined with iodine demonstrated additive effects against spirochetes and biofilm, whereas with fatty acids such as monolaurin and 10-HAD it produced FICIs of indifference. Additive anti-spirochetal effects were also observed when doxycycline was used with rosmarinic acid and both vitamins D3 and C. Antagonism was not observed in any of the cases. This data revealed the intrinsic anti-borreliae activity of doxycycline with tested phytochemicals and micronutrients indicating that their addition may enhance efficacy of this antibiotic in combating Borrelia sp. Especially the addition of flavones balcalein and luteolin to a doxycycline regimen could be explored further in defining more effective treatments against these bacteria. PMID:27570483

  7. Variable exposure and immunological response to Lyme disease Borrelia among North Atlantic seabird species

    PubMed Central

    Staszewski, V; McCoy, K.D; Boulinier, T

    2008-01-01

    Colonial seabirds often breed in large aggregations. These individuals can be exposed to parasitism by the tick Ixodes uriae, but little is known about the circulation of pathogens carried by this ectoparasite, including Lyme disease Borrelia. Here we investigated the prevalence of antibodies (Ab) against Borrelia burgdorferi sensu lato in seabird species sampled at eight locations across the North Atlantic. Using enzyme-linked immunosorbent assay tests, we found that the prevalence of anti-Borrelia Ab in adult seabirds was 39.6% on average (over 444 individuals), but that it varied among colonies and species. Common guillemots showed higher seroprevalence (77.1%±5.9) than black-legged kittiwakes (18.6%±6.7) and Atlantic puffins (22.6%±6.3). Immunoblot-banding patterns of positive individuals, reflecting the variability of Borrelia antigens against which Ab were produced, also differed among locations and species, and did not tightly match the prevalence of Borrelia phylogroups previously identified in ticks collected from the same host individuals. These results represent the first report of the widespread prevalence of Ab against Borrelia within an assemblage of seabird species and demonstrate that Borrelia is an integrated aspect in the interaction between seabirds and ticks. More detailed studies on the dynamics of Borrelia within and among seabird species at different spatial scales will now be required to better understand the implications of this interaction for seabird ecology and the epidemiology of Lyme disease. PMID:18577503

  8. Mercury exposure as a model for deviation of cytokine responses in experimental Lyme arthritis: HgCl2 treatment decreases T helper cell type 1-like responses and arthritis severity but delays eradication of Borrelia burgdorferi in C3H/HeN mice

    PubMed Central

    Ekerfelt, C; Andersson, M; Olausson, A; Bergström, S; Hultman, P

    2007-01-01

    Lyme borreliosis is a complex infection, where some individuals develop so-called ‘chronic borreliosis’. The pathogenetic mechanisms are unknown, but the type of immune response is probably important for healing. A strong T helper cell type 1 (Th1)-like response has been suggested as crucial for eradication of Borrelia and for avoiding development of chronic disease. Many studies aimed at altering the Th1/Th2 balance in Lyme arthritis employed mice deficient in cytokine genes, but the outcome has not been clear-cut, due possibly to the high redundancy of cytokines. This study aimed at studying the importance of the Th1/Th2 balance in murine Borrelia arthritis by using the Th2-deviating effect of subtoxic doses of inorganic mercury. Ninety-eight C3H/HeN mice were divided into four groups: Borrelia-infected (Bb), Borrelia-infected exposed to HgCl2 (BbHg), controls exposed to HgCl2 alone and normal controls. Mice were killed on days 3, 16, 44 and 65 post-Borrelia inoculation. Arthritis severity was evaluated by histology, spirochaetal load determined by Borrelia culture, IgG2a- and IgE-levels analysed by enzyme-linked immunosorbemt assay (ELISA) and cytokine-secreting cells detected by enzyme-linked immunospot (ELISPOT). BbHg mice showed less severe histological arthritis, but delayed eradication of spirochaetes compared to Bb mice, associated with increased levels of IgE (Th2-induced) and decreased levels of IgG2a (Th1-induced), consistent with a Th2-deviation. Both the numbers of Th1 and Th2 cytokine-secreting cells were reduced in BbHg mice, possibly explained by the fact that numbers of cytokine-secreting cells do not correlate with cytokine concentration. In conclusion, this study supports the hypothesis that a Th1-like response is required for optimal eradication of Borrelia. PMID:17672870

  9. Associations of passerine birds, rabbits, and ticks with Borrelia miyamotoi and Borrelia andersonii in Michigan, U.S.A.

    PubMed Central

    2012-01-01

    Background Wild birds contribute to maintenance and dissemination of vectors and microbes, including those that impact human, domestic animal, and wildlife health. Here we elucidate roles of wild passerine birds, eastern cottontail rabbits (Sylvilagus floridanus), and Ixodes dentatus ticks in enzootic cycles of two spirochetes, Borrelia miyamotoi and B. andersonii in a region of Michigan where the zoonotic pathogen B. burgdorferi co-circulates. Methods Over a four-year period, wild birds (n = 19,631) and rabbits (n = 20) were inspected for tick presence and ear tissue was obtained from rabbits. Samples were tested for Borrelia spirochetes using nested PCR of the 16S-23S rRNA intergenic spacer region (IGS) and bidirectional DNA sequencing. Natural xenodiagnosis was used to implicate wildlife reservoirs. Results Ixodes dentatus, a tick that specializes on birds and rabbits and rarely bites humans, was the most common tick found, comprising 86.5% of the 12,432 ticks collected in the study. The relapsing fever group spirochete B. miyamotoi was documented for the first time in ticks removed from wild birds (0.7% minimum infection prevalence; MIP, in I. dentatus), and included two IGS strains. The majority of B. miyamotoi-positive ticks were removed from Northern Cardinals (Cardinalis cardinalis). Borrelia andersonii infected ticks removed from birds (1.6% MIP), ticks removed from rabbits (5.3% MIP), and rabbit ear biopsies (5%) comprised twelve novel IGS strains. Six species of wild birds were implicated as reservoirs for B. andersonii. Frequency of I. dentatus larval and nymphal co-feeding on birds was ten times greater than expected by chance. The relatively well-studied ecology of I. scapularis and the Lyme disease pathogen provides a context for understanding how the phenology of bird ticks may impact B. miyamotoi and B. andersonii prevalence and host associations. Conclusions Given the current invasion of I. scapularis, a human biting species that serves as a

  10. Potentially conflicting selective forces that shape the vls antigenic variation system in Borrelia burgdorferi

    PubMed Central

    Zhou, Wei; Brisson, Dustin

    2014-01-01

    Changing environmental conditions present an evolutionary challenge for all organisms. The environment of microbial pathogens, including the adaptive immune responses of the infected host, changes rapidly and is lethal to the pathogen lineages that cannot quickly adapt. The dynamic immune environment creates strong selective pressures favoring microbial pathogen lineages with antigenic variation systems that maximize the antigenic divergence among expressed antigenic variants. However, divergence among expressed antigens may be constrained by other molecular features such as the efficient expression of functional proteins. We computationally examined potential conflicting selection pressures on antigenic variation systems using the vls antigenic variation system in Borrelia burgdorferi as a model system. The vls system alters the sequence of the expressed antigen by recombining gene fragments from unexpressed but divergent ‘cassettes’ into the expression site, vlsE. The in silico analysis of natural and altered cassettes from seven lineages in the B. burgdorferi sensu lato species complex revealed that sites that are polymorphic among unexpressed cassettes, as well as the insertion/deletion mutations, are organized to maximize divergence among the expressed antigens within the constraints of translational ability and high translational efficiency. This study provides empirical evidence that conflicting selection pressures on antigenic variation systems can limit the potential antigenic divergence in order to maintain proper molecular function. PMID:24837669

  11. Borrelia burgdorferi sensu lato and co-infections with Anaplasma phagocytophilum and Rickettsia spp. in Ixodes ricinus in Hamburg, Germany.

    PubMed

    May, K; Jordan, D; Fingerle, V; Strube, C

    2015-12-01

    To obtain initial data on Borrelia burgdorferi sensu lato (Spirochaetales: Spirochaetaceae) in Ixodes ricinus (Ixodida: Ixodidae) ticks in Hamburg, Germany, 1400 questing ticks were collected by flagging at 10 different public recreation areas in 2011 and analysed using probe-based quantitative real-time polymerase chain reaction. The overall rate of infection with B. burgdorferi s.l. was 34.1%; 30.0% of adults were infected (36.7% of females and 26.0% of males), as were 34.5% of nymphs. Significant differences in tick infection rates were observed between the spring and summer/autumn months, as well as among sampling locations. Borrelia genospecies identification by reverse line blotting was successful in 43.6% of positive tick samples. The most frequent genospecies was Borrelia garinii/Borrelia bavariensis, followed by Borrelia afzelii, Borrelia valaisiana, B. burgdorferi sensu stricto, Borrelia spielmanii, Borrelia bissettii and Borrelia lusitaniae. Based on previously published data, co-infection of Borrelia and Rickettsiales spp. was determined in 25.8% of ticks. Overall, 22.9% of ticks were co-infected with Rickettsia spp. (Rickettsiales: Rickettsiaceae), 1.7% with Anaplasma phagocytophilum (Rickettsiales: Anaplasmataceae), and 1.2% with both pathogens. Study results show a high prevalence of Borrelia-positive ticks in recreation areas in the northern German city of Hamburg and the potential health risk to humans in these areas should not be underestimated. PMID:26096626

  12. Engineering of Immunoglobulin Fc Heterodimers Using Yeast Surface-Displayed Combinatorial Fc Library Screening

    PubMed Central

    Choi, Hye-Ji; Kim, Ye-Jin; Choi, Dong-Ki; Kim, Yong-Sung

    2015-01-01

    Immunoglobulin Fc heterodimers, which are useful scaffolds for the generation of bispecific antibodies, have been mostly generated through structure-based rational design methods that introduce asymmetric mutations into the CH3 homodimeric interface to favor heterodimeric Fc formation. Here, we report an approach to generate heterodimeric Fc variants through directed evolution combined with yeast surface display. We developed a combinatorial heterodimeric Fc library display system by mating two haploid yeast cell lines, one haploid cell line displayed an Fc chain library (displayed FcCH3A) with mutations in one CH3 domain (CH3A) on the yeast cell surface, and the other cell line secreted an Fc chain library (secreted FcCH3B) with mutations in the other CH3 domain (CH3B). In the mated cells, secreted FcCH3B is displayed on the cell surface through heterodimerization with the displayed FcCH3A, the detection of which enabled us to screen the library for heterodimeric Fc variants. We constructed combinatorial heterodimeric Fc libraries with simultaneous mutations in the homodimer-favoring electrostatic interaction pairs K370-E357/S364 or D399-K392/K409 at the CH3 domain interface. High-throughput screening of the libraries using flow cytometry yielded heterodimeric Fc variants with heterodimer-favoring CH3 domain interface mutation pairs, some of them showed high heterodimerization yields (~80–90%) with previously unidentified CH3 domain interface mutation pairs, such as hydrogen bonds and cation-π interactions. Our study provides a new approach for engineering Fc heterodimers that could be used to engineer other heterodimeric protein-protein interactions through directed evolution combined with yeast surface display. PMID:26675656

  13. Heterodimer Autorepression Loop: A Robust and Flexible Pulse-Generating Genetic Module

    NASA Astrophysics Data System (ADS)

    Lannoo, B.; Carlon, E.; Lefranc, M.

    2016-07-01

    We investigate the dynamics of the heterodimer autorepression loop (HAL), a small genetic module in which a protein A acts as an autorepressor and binds to a second protein B to form an A B dimer. For suitable values of the rate constants, the HAL produces pulses of A alternating with pulses of B . By means of analytical and numerical calculations, we show that the duration of A pulses is extremely robust against variation of the rate constants while the duration of the B pulses can be flexibly adjusted. The HAL is thus a minimal genetic module generating robust pulses with a tunable duration, an interesting property for cellular signaling.

  14. Improved method for assembly of hemeprotein neuronal NO-synthase heterodimers.

    PubMed

    Morishima, Yoshihiro; Zhang, Haoming; Lau, Miranda; Osawa, Yoichi

    2016-10-15

    The assembly of mutated and wild type monomers into functional heterodimeric hemeproteins has provided important mechanistic insights. As in the case of NO synthase (NOS), the existing methods to make such heterodimeric NOSs are inefficient and labor intensive with typical yields of about 5%. We have found that expression of neuronal NOS heterodimers in insect cells, where we take advantage of an exogenous heme-triggered chaperone-assisted assembly process, provides an approximately 43% yield in heterodimeric NOS. In contrast, in Escherichia coli little heterodimerization occurred. Thus, insect cells are preferred and may represent a valuable method for assembly of other dimeric hemeproteins. PMID:27487179

  15. Farnesoid X Receptor Agonist Represses Cytochrome P450 2D6 Expression by Upregulating Small Heterodimer Partner.

    PubMed

    Pan, Xian; Lee, Yoon-Kwang; Jeong, Hyunyoung

    2015-07-01

    Cytochrome P450 2D6 (CYP2D6) is a major drug-metabolizing enzyme responsible for eliminating approximately 20% of marketed drugs. Studies have shown that differential transcriptional regulation of CYP2D6 may contribute to large interindividual variability in CYP2D6-mediated drug metabolism. However, the factors governing CYP2D6 transcription are largely unknown. We previously demonstrated small heterodimer partner (SHP) as a novel transcriptional repressor of CYP2D6 expression. SHP is a representative target gene of the farnesoid X receptor (FXR). The objective of this study is to investigate whether an agonist of FXR, 3-(2,6-dichlorophenyl)-4-(3'-carboxy-2-chlorostilben-4-yl)oxymethyl-5-isopropylisoxazole (GW4064), alters CYP2D6 expression and activity. In CYP2D6-humanized transgenic mice, GW4064 decreased hepatic CYP2D6 expression and activity (by 2-fold) while increasing SHP expression (by 2-fold) and SHP recruitment to the CYP2D6 promoter. CYP2D6 repression by GW4064 was abrogated in Shp(-/-);CYP2D6 mice, indicating a critical role of SHP in CYP2D6 regulation by GW4064. Also, GW4064 decreased CYP2D6 expression (by 2-fold) in primary human hepatocytes, suggesting that the results obtained in CYP2D6-humanized transgenic mice can be translated to humans. This proof of concept study provides evidence for CYP2D6 regulation by an inducer of SHP expression, namely, the FXR agonist GW4064. PMID:25926433

  16. Heterodimers and homodimers of inhibin subunits have different paracrine action in the modulation of luteinizing hormone-stimulated androgen biosynthesis

    SciTech Connect

    Hsueh, A.J.W.; Dahl, K.D.; Vaughan, J.; Tucker, E.; Rivier, J.; Bardin, C.W.; Vale, W.

    1987-07-01

    Inhibin, a gonadal hormone capable of preferential suppression of pituitary follicle-stimulating hormone (FSH) secretion, has recently been purified. The major form of this protein is an ..cap alpha beta.. heterodimer encoded by two separate genes. In contrast to the FSH-suppressing action of the ..cap alpha beta.. heterodimer, the ..beta beta.. homodimer stimulates FSH secretion. Luteinizing hormone (LH)-secreting pituitary cells and gonadal androgen-producing cells have long been shown to form a closed-loop feedback axis. Based on recent studies demonstrated the FSH stimulation of inhibin biosynthesis by ovarian granulosa and testis Sertoli cells, an additional closed-loop feedback axis exists between pituitary FSH- and gonadal inhibin-producing cells. Because uncharacterized Sertoli cell factors have been suggested to either stimulate or inhibit androgen production by testicular Leydig cells, the authors have tested the intragonadal paracrine actions of heterodimers and homodimers of inhibin subunits. In primary cultures of testis cells, the ..cap alpha beta.. heterodimer of inhibin enhances Leydig cell androgen biosynthesis stimulated by LH, whereas the ..beta beta.. homodimer suppresses androgen production. The data indicate that the inhibin-related gene products synthesized by Sertoli and granulosa cells may form heterodimers or homodimers to serve as intragonadal paracrine signals in the modulation of LH-stimulated androgen biosynthesis and allow cross-communication between the two feedback loops.

  17. Prevalence of Borrelia burgdorferi sensu lato in ticks from eastern China.

    PubMed

    Hou, Juan; Ling, Feng; Chai, Chengliang; Lu, Ye; Yu, Xianghua; Lin, Junfen; Sun, Jimin; Chang, Yue; Ye, Xiaodong; Gu, Shiping; Pang, Weilong; Wang, Chengwei; Zheng, Xiaohua; Jiang, Jianmin; Chen, Zhiping; Gong, Zhenyu

    2015-02-01

    To explore the tick distribution and prevalence of Borrelia in Zhejiang Province, we performed a survey in nine sites. A total of 447 adult ticks of 11 species were captured and the dominant tick species were Haemaphysalis longicornis and Ixodes sinensis and the abundance of tick species in different areas varied significantly. Overall, 4.70% of the ticks were polymerase chain reaction (PCR) positive for Borrelia. The average PCR positive rates were 5.19% for H. longicornis, 3.45% for Amblyomma testudinarium, 1.06% for I. sinensis, 5.00% for Rhipicephalus (Boophilus) microplus, and 19.44% for Ixodes granulatus, respectively. No Borrelia DNA was detected in Rhiphicephalus haemaphysaloides, Haemaphysalis yeni, Dermacentor taiwanensis, Haemaphysalis hystricis, Hyalomna asiaticum, and Ixodes ovatus. The prevalence of Borrelia was significantly different among tick species and the prevalence in I. granulatus was significantly higher than that in other tick species. Of note, experimentally confirmed vectors for B. burgdorferi s.l. including I. sinensis and I. granulatus were found in Zhejiang Province. Two species of B. burgdorferi s.l. exist in Zhejiang Province of which 12 sequences were most similar to the sequence of Borrelia garinii and nine sequences were most similar to the sequence of Borrelia valaisiana or Borrelia yangtze sp. nov. PMID:25548382

  18. Borrelia infection in Ixodes pararicinus ticks (Acari: Ixodidae) from northwestern Argentina.

    PubMed

    Nava, Santiago; Barbieri, Amalia M; Maya, Leticia; Colina, Rodney; Mangold, Atilio J; Labruna, Marcelo B; Venzal, José M

    2014-11-01

    The aim of this work was to describe for the first time the presence of Borrelia burgdorferi sensu lato infecting ticks in Argentina. Unfed specimens of Ixodes pararicinus collected from vegetation in Jujuy Province were tested for Borrelia infection by PCR targeting the gene flagellin (fla), the rrfA-rrlB intergenic spacer region (IGS) and the 16S rDNA (rrs) gene. One male and one female of I. pararicinus collected in Jujuy were found to be positive to Borrelia infection with the three molecular markers tested. Phylogenetically, the Borrelia found in I. pararicinus from Jujuy belongs to the B. burgdorferi s.l complex, and it was similar to one of the genospecies detected in I. aragaoi from Uruguay. Also, this genospecies is closely related to two genospecies known from USA, Borrelia americana and the Borrelia sp. genospecies 1. The epidemiological risk that implies the infection with Borrelia in I. paracinus ticks from Argentina appears to be low because the genospecies detected is not suspected of having clinical relevance and there are no records of Ixodes ticks biting humans in the southern cone of South America. Further studies are needed to assess accurately if there is risk of borreliosis transmitted by ticks in South America. PMID:24979685

  19. Prevalence of Borrelia burgdorferi s. l. in Ixodes ricinus ticks from four localities in Bavaria, Germany.

    PubMed

    Vögerl, Maria; Zubriková, Dana; Pfister, Kurt

    2012-01-01

    As a part of a larger survey a total of 599 Ixodes ricinus ticks collected from four locations (Neustadt an der Waldnaab, Amberg, Poppenricht and Lintach) in the north of the Upper Palatinate in Bavaria were investigated for infection with Borrelia burgdorferi sensu lato (s. l.) species using the 5S-23S intergenic spacer of rRNA gene as a target in a nested PCR (Rijpkema et al., 1995) and a sequencing method. Overall, 15.8% ticks were infected with B. burgdorferi s. I. Borrelia afzelii (43.1%) was the predominant genospecies, followed by Borrelia valaisiana (14.7%), Borrelia garinii (13.7%) and Borrelia burgdorferi sensu stricto (6.3%). Also Borrelia spielmanii was found (1.1%). Of the infected ticks, 21.1% harbored multiple infections with B. burgdorferi s. I. The highest number of infected ticks was found in Amberg (22.5%) and the lowest number in Neustadt an der Waldnaab (11.9%). In Poppenricht and Lintach, the numbers of infected ticks were 12% and 18.7%, respectively. Human pathogenic Borrelia species were found to be prevalent at each study site thus representing the potential risk for people living and visiting these areas. PMID:23045802

  20. Whole-Genome Sequences of Thirteen Isolates of Borrelia burgdorferi

    SciTech Connect

    Schutzer S. E.; Dunn J.; Fraser-Liggett, C. M.; Casjens, S. R.; Qiu, W.-G.; Mongodin, E. F.; Luft, B. J.

    2011-02-01

    Borrelia burgdorferi is a causative agent of Lyme disease in North America and Eurasia. The first complete genome sequence of B. burgdorferi strain 31, available for more than a decade, has assisted research on the pathogenesis of Lyme disease. Because a single genome sequence is not sufficient to understand the relationship between genotypic and geographic variation and disease phenotype, we determined the whole-genome sequences of 13 additional B. burgdorferi isolates that span the range of natural variation. These sequences should allow improved understanding of pathogenesis and provide a foundation for novel detection, diagnosis, and prevention strategies.

  1. Production in Pichia pastoris of protein-based polymers with small heterodimer-forming blocks.

    PubMed

    Domeradzka, Natalia E; Werten, Marc W T; de Vries, Renko; de Wolf, Frits A

    2016-05-01

    Some combinations of leucine zipper peptides are capable of forming α-helical heterodimeric coiled coils with very high affinity. These can be used as physical cross-linkers in the design of protein-based polymers that form supramolecular structures, for example hydrogels, upon mixing solutions containing the complementary blocks. Such two-component physical networks are of interest for many applications in biomedicine, pharmaceutics, and diagnostics. This article describes the efficient secretory production of A and B type leucine zipper peptides fused to protein-based polymers in Pichia pastoris. By adjusting the fermentation conditions, we were able to significantly reduce undesirable proteolytic degradation. The formation of A-B heterodimers in mixtures of the purified products was confirmed by size exclusion chromatography. Our results demonstrate that protein-based polymers incorporating functional heterodimer-forming blocks can be produced with P. pastoris in sufficient quantities for use in future supramolecular self-assembly studies and in various applications. Biotechnol. Bioeng. 2016;113: 953-960. © 2015 Wiley Periodicals, Inc. PMID:26479855

  2. Taste substance binding elicits conformational change of taste receptor T1r heterodimer extracellular domains.

    PubMed

    Nango, Eriko; Akiyama, Shuji; Maki-Yonekura, Saori; Ashikawa, Yuji; Kusakabe, Yuko; Krayukhina, Elena; Maruno, Takahiro; Uchiyama, Susumu; Nuemket, Nipawan; Yonekura, Koji; Shimizu, Madoka; Atsumi, Nanako; Yasui, Norihisa; Hikima, Takaaki; Yamamoto, Masaki; Kobayashi, Yuji; Yamashita, Atsuko

    2016-01-01

    Sweet and umami tastes are perceived by T1r taste receptors in oral cavity. T1rs are class C G-protein coupled receptors (GPCRs), and the extracellular ligand binding domains (LBDs) of T1r1/T1r3 and T1r2/T1r3 heterodimers are responsible for binding of chemical substances eliciting umami or sweet taste. However, molecular analyses of T1r have been hampered due to the difficulties in recombinant expression and protein purification, and thus little is known about mechanisms for taste perception. Here we show the first molecular view of reception of a taste substance by a taste receptor, where the binding of the taste substance elicits a different conformational state of T1r2/T1r3 LBD heterodimer. Electron microscopy has showed a characteristic dimeric structure. Förster resonance energy transfer and X-ray solution scattering have revealed the transition of the dimerization manner of the ligand binding domains, from a widely spread to compactly organized state upon taste substance binding, which may correspond to distinct receptor functional states. PMID:27160511

  3. Taste substance binding elicits conformational change of taste receptor T1r heterodimer extracellular domains

    PubMed Central

    Nango, Eriko; Akiyama, Shuji; Maki-Yonekura, Saori; Ashikawa, Yuji; Kusakabe, Yuko; Krayukhina, Elena; Maruno, Takahiro; Uchiyama, Susumu; Nuemket, Nipawan; Yonekura, Koji; Shimizu, Madoka; Atsumi, Nanako; Yasui, Norihisa; Hikima, Takaaki; Yamamoto, Masaki; Kobayashi, Yuji; Yamashita, Atsuko

    2016-01-01

    Sweet and umami tastes are perceived by T1r taste receptors in oral cavity. T1rs are class C G-protein coupled receptors (GPCRs), and the extracellular ligand binding domains (LBDs) of T1r1/T1r3 and T1r2/T1r3 heterodimers are responsible for binding of chemical substances eliciting umami or sweet taste. However, molecular analyses of T1r have been hampered due to the difficulties in recombinant expression and protein purification, and thus little is known about mechanisms for taste perception. Here we show the first molecular view of reception of a taste substance by a taste receptor, where the binding of the taste substance elicits a different conformational state of T1r2/T1r3 LBD heterodimer. Electron microscopy has showed a characteristic dimeric structure. Förster resonance energy transfer and X-ray solution scattering have revealed the transition of the dimerization manner of the ligand binding domains, from a widely spread to compactly organized state upon taste substance binding, which may correspond to distinct receptor functional states. PMID:27160511

  4. Early Cytokine Release in Response to Live Borrelia burgdorferi Sensu Lato Spirochetes Is Largely Complement Independent

    PubMed Central

    Säve, Susanne; Bergström, Sven; Forsberg, Pia; Jonsson, Nina; Ernerudh, Jan; Ekdahl, Kristina N.

    2014-01-01

    Aim Here we investigated the role of complement activation in phagocytosis and the release of cytokines and chemokines in response to two clinical isolates: Borrelia afzelii K78, which is resistant to complement-mediated lysis, and Borrelia garinii LU59, which is complement-sensitive. Methods Borrelia spirochetes were incubated in hirudin plasma, or hirudin-anticoagulated whole blood. Complement activation was measured as the generation of C3a and sC5b-9. Binding of the complement components C3, factor H, C4, and C4BP to the bacterial surfaces was analyzed. The importance of complement activation on phagocytosis, and on the release of cytokines and chemokines, was investigated using inhibitors acting at different levels of the complement cascade. Results 1) Borrelia garinii LU59 induced significantly higher complement activation than did Borrelia afzelii K78. 2) Borrelia afzelii K78 recruited higher amounts of factor H resulting in significantly lower C3 binding. 3) Both Borrelia strains were efficiently phagocytized by granulocytes and monocytes, with substantial inhibition by complement blockade at the levels of C3 and C5. 4) The release of the pro-inflammatory cytokines and chemokines IL-1β, IL-6, TNF, CCL20, and CXCL8, together with the anti-inflammatory IL-10, were increased the most (by>10-fold after exposure to Borrelia). 5) Both strains induced a similar release of cytokines and chemokines, which in contrast to the phagocytosis, was almost totally unaffected by complement blockade. Conclusions Our results show that complement activation plays an important role in the process of phagocytosis but not in the subsequent cytokine release in response to live Borrelia spirochetes. PMID:25265036

  5. Infection of Ixodes ricinus (Acari: Ixodidae) by Borrelia burgdorferi sensu lato in North Africa

    USGS Publications Warehouse

    Zhioua, E.; Bouattour, A.; Hu, C.M.; Gharbi, M.; Aeschliman, A.; Ginsberg, H.S.; Gern, L.

    1999-01-01

    Free-living adult Ixodes ricinus L. were collected in Amdoun, situated in the Kroumiry mountains in northwestern Tunisia (North Africa). Using direct fluorescence antibody assay, the infection rate of field-collected I. ricinus by Borrelia burgdorferi sensu lato was 30.5% (n = 72). No difference in infection rate was observed between male and female ticks. Spirochetes that had been isolated from I. ricinus from Ain Drahim (Kroumiry Mountains) in 1988 were identified as Borrelia lusitaniae (formerly genospecies PotiB2). This is the first identification of a genospecies of Borrelia burgdorferi sensu lato from the continent of Africa.

  6. BB0323 function is essential for Borrelia burgdorferi virulence and persistence through tick-rodent transmission cycle

    PubMed Central

    Zhang, Xinyue; Yang, Xiuli; Kumar, Manish; Pal, Utpal

    2010-01-01

    Borrelia burgdorferi bb0323 encodes an immunogenic protein in mammalian hosts including humans. An analysis of bb0323 expression in vivo showed variable transcription throughout the spirochete infection cycle, with elevated expression during tick-mouse transmission. Deletion of bb0323 in infectious B. burgdorferi did not affect microbial survival in vitro, despite significant alterations in growth kinetics and cell morphology. bb0323 mutants were unable to infect either mice or ticks, and were quickly eliminated from immunocompetent and immunodeficient hosts and the vector, within the first few days of inoculation. Chromosomal complementation of the mutant with native bb0323 and phenotypic analysis in vivo indicated the significant restoration of spirochete virulence and persistence throughout the mouse-tick infection cycle. BB0323 may serve an indispensable physiological function that is more pronounced during microbial persistence and transitions between the host and the vector in vivo. Strategies to interfere with BB0323 function may interrupt the infectious cycle of spirochetes. PMID:19754308

  7. Case Report: Bilateral diaphragmatic dysfunction due to Borrelia Burgdorferi

    PubMed Central

    Basunaid, Suhail; van der Grinten, Chris; Cobben, Nicole; Otte, Astrid; Sprooten, Roy; Gernot, Rohde

    2014-01-01

    Summary: In this case report we describe a rare case of bilateral diaphragmatic dysfunction due to Lyme disease. Case report: A 62-years-old male presented to the hospital because of flu-like symptoms. During initial evaluation a bilateral diaphragmatic weakness with orthopnea and nocturnal hypoventilation was observed, without a known aetiology. Bilateral diaphragmatic paralysis was confirmed by fluoroscopy with a positive sniff test. The patient was referred to our centre for chronic non-invasive nocturnal ventilation (cNPPV). Subsequent investigations revealed evidence of anti- Borrelia seroactivity in EIA-IgG and IgG-blot, suggesting a recent infection with Lyme disease, and resulted in a 4-week treatment with oral doxycycline. The symptoms of nocturnal hypoventilation were successfully improved with cNPPV. However, our patient still shows impaired diaphragmatic function but he is no longer fully dependent on nocturnal ventilatory support.     Conclusion: Lyme disease should be considered in the differential diagnosis of diaphragmatic dysfunction. It is a tick-borne illness caused by one of the three pathogenic species of the spirochete Borrelia burgdorferi, present in Europe. A delay in recognizing the symptoms can negatively affect the success of treatment. Non-invasive mechanical ventilation (NIV) is considered a treatment option for patients with diaphragmatic paralysis. PMID:25671085

  8. [Case of Borrelia brainstem encephalitis presenting with severe dysphagia].

    PubMed

    Kawano, Yuji; Shigeto, Hiroshi; Shiraishi, Yoshimasa; Ohyagi, Yasumasa; Kira, Jun-Ichi

    2010-04-01

    We report the case of a 30-year-old man who developed severe dysphagia owing to neuroborreliosis. He showed dysphagia, diplopia, hiccups, and walking difficulty Neurological examination revealed mild disturbance of consciousness, diplopia on left lateral gaze, left-side-dominant blephaloptosis, gaze-evoked horizontal nystagmus on left lateral gaze, mild bilateral muscle weakness, palatoplegia, dysphagia, dysarthria, and truncal ataxia An increased pharyngeal reflex caused dysphagia in this patient. An EEG revealed intermittent high amplitude slow wave activity. However, head MRI, blood count, serum chemistry, and cerebrospinal fluid examination showed no abnormality. Initially, brainstem encephalitis with unknown etiology was diagnosed. The hiccups, diplopia, and ptosis were improved by corticosteroid therapy, but other symptoms were refractory to corticosteroid therapy and IVIg. After these immunotherapies, anti-Borrelia IgG and IgM antibodies were found to be positive, and symptoms, including dysphagia, were improved by doxycycline and cefotaxime. Because the clinical symptoms of Borrelia infection are widely variable, neuroborreliosis should be considered in patients with brainstem encephalitis refractory to conventional immunotherapies. PMID:20411811

  9. Antigenic variation with a twist--the Borrelia story.

    PubMed

    Norris, Steven J

    2006-06-01

    A common mechanism of immune evasion in pathogenic bacteria and protozoa is antigenic variation, in which genetic or epigenetic changes result in rapid, sequential shifts in a surface-exposed antigen. In this issue of Molecular Microbiology, Dai et al. provide the most complete description to date of the vlp/vsp antigenic variation system of the relapsing fever spirochaete, Borrelia hermsii. This elaborate, plasmid-encoded system involves an expression site that can acquire either variable large protein (vlp) or variable small protein (vsp) surface lipoprotein genes from 59 different archival copies. The archival vlp and vsp genes are arranged in clusters on at least five different plasmids. Gene conversion occurs through recombination events at upstream homology sequences (UHS) found in each gene copy, and at downstream homology sequences (DHS) found periodically among the vlp/vsp archival genes. Previous studies have shown that antigenic variation in relapsing fever Borrelia not only permits the evasion of host antibody responses, but can also result in changes in neurotropism and other pathogenic properties. The vlsE antigenic variation locus of Lyme disease spirochaetes, although similar in sequence to the relapsing fever vlp genes, has evolved a completely different antigenic variation mechanism involving segmental recombination from a contiguous array of vls silent cassettes. These two systems thus appear to represent divergence from a common precursor followed by functional convergence to create two distinct antigenic variation processes. PMID:16796669

  10. Apparent Role for Borrelia burgdorferi LuxS during Mammalian Infection

    PubMed Central

    Arnold, William K.; Savage, Christina R.; Antonicello, Alyssa D.

    2015-01-01

    The Lyme disease spirochete, Borrelia burgdorferi, controls protein expression patterns during its tick-mammal infection cycle. Earlier studies demonstrated that B. burgdorferi synthesizes 4,5-dihydroxy-2,3-pentanedione (autoinducer-2 [AI-2]) and responds to AI-2 by measurably changing production of several infection-associated proteins. luxS mutants, which are unable to produce AI-2, exhibit altered production of several proteins. B. burgdorferi cannot utilize the other product of LuxS, homocysteine, indicating that phenotypes of luxS mutants are not due to the absence of that molecule. Although a previous study found that a luxS mutant was capable of infecting mice, a critical caveat to those results is that bacterial loads were not quantified. To more precisely determine whether LuxS serves a role in mammalian infection, mice were simultaneously inoculated with congenic wild-type and luxS strains, and bacterial numbers were assessed using quantitative PCR. The wild-type bacteria substantially outcompeted the mutants, suggesting that LuxS performs a significant function during mammalian infection. These data also provide further evidence that nonquantitative infection studies do not necessarily provide conclusive results and that regulatory factors may not make all-or-none, black-or-white contributions to infectivity. PMID:25605770

  11. Evidence that BosR (BB0647) Is a Positive Autoregulator in Borrelia burgdorferi.

    PubMed

    Ouyang, Zhiming; Zhou, Jianli; Norgard, Michael V

    2016-09-01

    Borrelia burgdorferi survives in nature through a complex tick-mammalian life cycle. During its transit between ticks and mammalian hosts, B. burgdorferi must dramatically alter its outer surface profile in order to interact with and adapt to these two diverse niches. It has been established that the regulator BosR (BB0647) in B. burgdorferi plays important roles in modulating borrelial host adaptation. However, to date, how bosR expression itself is controlled in B. burgdorferi remains largely unknown. Previously, it has been shown that DNA sequences upstream of BosR harbor multiple sites for the binding of recombinant BosR, suggesting that BosR may influence its own expression in B. burgdorferi However, direct experimental evidence supporting this putative autoregulation of BosR has been lacking. Here, we investigated the expression of bosR throughout the tick-mammal life cycle of B. burgdorferi via quantitative reverse transcription (RT)-PCR analyses. Our data indicated that bosR is expressed not only during mouse infection, but also during the tick acquisition, intermolt, and transmission phases. Further investigation revealed that bosR expression in B. burgdorferi is influenced by environmental stimuli, such as temperature shift and pH change. By employing luciferase reporter assays, we also identified two promoters potentially driving bosR transcription. Our study offers strong support for the long-postulated function of BosR as an autoregulator in B. burgdorferi. PMID:27324485

  12. Seasonal prevalence of Borrelia burgdorferi in natural populations of white-footed mice, Peromyscus leucopus.

    PubMed

    Anderson, J F; Johnson, R C; Magnarelli, L A

    1987-08-01

    Borrelia burgdorferi, the etiologic agent of Lyme disease, was isolated from 111 of 237 Peromyscus leucopus captured during all seasons of the year. Borreliae were cultured from tissues of the spleen (101 mice), left kidney (76 mice), and right kidney (73 mice), from blood (12 mice), and from one fetus. Mice were infected during the winter, when immature Ixodes dammini were inactive. The prevalence of infection during the winter (less than or equal to 33%) was more than twofold lower than that during the summer (ca. 75%), a time when nymphal ticks are abundant. Overwintering, infected mice are reservoir hosts for subadult ticks that begin feeding in early spring. Twenty white-footed mice from which B. burgdorferi was isolated from tissues of spleen or kidney but not from blood were parasitized by larval I. dammini or Dermacentor variabilis which harbored borreliae. We conclude that these mice were infectious to feeding ticks, even though borreliae were not isolated from blood. PMID:3624451

  13. Sensitivity of Borrelia genospecies to serum complement from different animals and human: a host-pathogen relationship.

    PubMed

    Bhide, Mangesh R; Travnicek, Milan; Levkutova, Maria; Curlik, Jan; Revajova, Viera; Levkut, Mikulas

    2005-02-01

    Different Borrelia species and serotypes were tested for their sensitivity to serum complement from various animals and human. Complement-mediated Borrelia killing in cattle, European bison and deer was higher irrespective of the Borrelia species whereas in other animals and human it was intermediate and Borrelia species-dependent. Activation of the alternative complement pathway by particular Borrelia strain was in correlation with its sensitivity or resistance. These results support the incompetent reservoir nature of cattle, European bison, red, roe and fallow deer, at the same time present the probable reservoir nature of mouflon, dog, wolf, cat and lynx. In short, this study reviews Borrelia-host relationship and its relevance in reservoir competence nature of animals. PMID:15681146

  14. SMRT isoforms mediate repression and anti-repression of nuclear receptor heterodimers.

    PubMed Central

    Chen, J D; Umesono, K; Evans, R M

    1996-01-01

    Transcriptional repression represents an important component in the regulation of cell differentiation and oncogenesis mediated by nuclear hormone receptors. Hormones act to relieve repression, thus allowing receptors to function as transcriptional activators. The transcriptional corepressor SMRT was identified as a silencing mediator for retinoid and thyroid hormone receptors. SMRT is highly related to another corepressor, N-CoR, suggesting the existence of a new family of receptor-interacting proteins. We demonstrate that SMRT is a ubiquitous nuclear protein that interacts with unliganded receptor heterodimers in mammalian cells. Furthermore, expression of the receptor-interacting domain of SMRT acts as an antirepressor, suggesting the potential importance of splicing variants as modulators of thyroid hormone and retinoic acid signaling. Images Fig. 1 Fig. 2 Fig. 4 Fig. 5 PMID:8755515

  15. A New Borrelia Species Defined by Multilocus Sequence Analysis of Housekeeping Genes▿ †

    PubMed Central

    Margos, Gabriele; Vollmer, Stephanie A.; Cornet, Muriel; Garnier, Martine; Fingerle, Volker; Wilske, Bettina; Bormane, Antra; Vitorino, Liliana; Collares-Pereira, Margarida; Drancourt, Michel; Kurtenbach, Klaus

    2009-01-01

    Analysis of Lyme borreliosis (LB) spirochetes, using a novel multilocus sequence analysis scheme, revealed that OspA serotype 4 strains (a rodent-associated ecotype) of Borrelia garinii were sufficiently genetically distinct from bird-associated B. garinii strains to deserve species status. We suggest that OspA serotype 4 strains be raised to species status and named Borrelia bavariensis sp. nov. The rooted phylogenetic trees provide novel insights into the evolutionary history of LB spirochetes. PMID:19542332

  16. Response Regulator Heterodimer Formation Controls a Key Stage in Streptomyces Development

    PubMed Central

    Al-Bassam, Mahmoud M.; Bibb, Maureen J.; Bush, Matthew J.; Chandra, Govind; Buttner, Mark J.

    2014-01-01

    The orphan, atypical response regulators BldM and WhiI each play critical roles in Streptomyces differentiation. BldM is required for the formation of aerial hyphae, and WhiI is required for the differentiation of these reproductive structures into mature spores. To gain insight into BldM function, we defined the genome-wide BldM regulon using ChIP-Seq and transcriptional profiling. BldM target genes clustered into two groups based on their whi gene dependency. Expression of Group I genes depended on bldM but was independent of all the whi genes, and biochemical experiments showed that Group I promoters were controlled by a BldM homodimer. In contrast, Group II genes were expressed later than Group I genes and their expression depended not only on bldM but also on whiI and whiG (encoding the sigma factor that activates whiI). Additional ChIP-Seq analysis showed that BldM Group II genes were also direct targets of WhiI and that in vivo binding of WhiI to these promoters depended on BldM and vice versa. We go on to demonstrate that BldM and WhiI form a functional heterodimer that controls Group II promoters, serving to integrate signals from two distinct developmental pathways. The BldM-WhiI system thus exemplifies the potential of response regulator heterodimer formation as a mechanism to expand the signaling capabilities of bacterial cells. PMID:25101778

  17. Primary charge separation within P870* in wild type and heterodimer mutants in femtosecond time domain.

    PubMed

    Khatypov, R A; Khmelnitskiy, A Yu; Khristin, A M; Fufina, T Yu; Vasilieva, L G; Shuvalov, V A

    2012-08-01

    Primary charge separation dynamics in the reaction center (RC) of purple bacterium Rhodobacter sphaeroides and its P870 heterodimer mutants have been studied using femtosecond time-resolved spectroscopy with 20 and 40fs excitation at 870nm at 293K. Absorbance increase in the 1060-1130nm region that is presumably attributed to P(A)(δ+) cation radical molecule as a part of mixed state with a charge transfer character P*(P(A)(δ+)P(B)(δ-)) was found. This state appears at 120-180fs time delay in the wild type RC and even faster in H(L173)L and H(M202)L heterodimer mutants and precedes electron transfer (ET) to B(A) bacteriochlorophyll with absorption band at 1020nm in WT. The formation of the P(A)(δ+)B(A)(δ-) state is a result of the electron transfer from P*(P(A)(δ+)P(B)(δ-)) to the primary electron acceptor B(A) (still mixed with P*) with the apparent time delay of ~1.1ps. Next step of ET is accompanied by the 3-ps appearance of bacteriopheophytin a(-) (H(A)(-)) band at 960nm. The study of the wave packet formation upon 20-fs illumination has shown that the vibration energy of the wave packet promotes reversible overcoming of an energy barrier between two potential energy surfaces P* and P*(P(A)(δ+)B(A)(δ-)) at ~500fs. For longer excitation pulses (40fs) this promotion is absent and tunneling through an energy barrier takes about 3ps. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial. PMID:22209778

  18. Synanthropic birds influence the distribution of Borrelia species: analysis of Ixodes ricinus ticks feeding on passerine birds.

    PubMed

    Dubska, Lenka; Literak, Ivan; Kocianova, Elena; Taragelova, Veronika; Sverakova, Veronika; Sychra, Oldrich; Hromadko, Miloslav

    2011-02-01

    Ixodes ricinus ticks collected from 835 birds and from vegetation in the Czech Republic were analyzed. Host-seeking ticks (n = 427) were infected predominantly by Borrelia afzelii (25%). Ticks (n = 1,012) from songbirds (Passeriformes) were infected commonly by Borrelia garinii (12.1%) and Borrelia valaisiana (13.4%). Juveniles of synanthropic birds, Eurasian blackbirds (Turdus merula) and song thrushes (Turdus philomelos), were major reservoir hosts of B. garinii. PMID:21148704

  19. Both Homo and Heterodimers of Marek's Disease Virus Encoded Meq Protein Contribute to Transformation of Lymphocytes in Chickens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Marek’s disease virus (MDV) elicits T-cell lymphomas in chickens. The MDV genome encodes an oncoprotein, Meq, with similarity to the Jun/Fos family of proteins. Similar to Jun, the leucine zipper region of Meq allows the formation of homo- and heterodimers. We have previously shown that Meq homodime...

  20. Synthesis of heterodimer radionuclide nanoparticles for magnetic resonance and single-photon emission computed tomography dual-modality imaging

    NASA Astrophysics Data System (ADS)

    Zhu, Jing; Zhang, Bin; Tian, Jian; Wang, Jiaqing; Chong, Yu; Wang, Xin; Deng, Yaoyao; Tang, Minghua; Li, Yonggang; Ge, Cuicui; Pan, Yue; Gu, Hongwei

    2015-02-01

    We report a facile synthesis of bifunctional Fe3O4-Ag125I heterodimers for use as dual-modality imaging agents in magnetic resonance (MR) and single-photon emission computed tomography (SPECT). We introduced 125I, which is a clinically used radioisotope, as a SPECT reporter, into Fe3O4-Ag heterodimer nanoparticles to provide a new type of bifunctional contrast agent for MRI and SPECT imaging.We report a facile synthesis of bifunctional Fe3O4-Ag125I heterodimers for use as dual-modality imaging agents in magnetic resonance (MR) and single-photon emission computed tomography (SPECT). We introduced 125I, which is a clinically used radioisotope, as a SPECT reporter, into Fe3O4-Ag heterodimer nanoparticles to provide a new type of bifunctional contrast agent for MRI and SPECT imaging. Electronic supplementary information (ESI) available: Details of general experimental procedures, TEM image. See DOI: 10.1039/c4nr07255c

  1. Turning a Negative into a Positive: Conversion of a Homodimer into a Heterodimer Using Negative State Repertoires.

    PubMed

    Davey, James A; Chica, Roberto A

    2016-04-01

    In this issue of Structure, Leaver-Fay et al. (2016) engineer bispecific antibodies using multistate computational protein design with negative state repertoires. In combination with additional mutations selected rationally, they produced antibodies that assembled as heterodimers with up to 93% purity. PMID:27050684

  2. A Versatile Self-Assembly Strategy for the Synthesis of Shape-Selected Colloidal Noble Metal Nanoparticle Heterodimers

    PubMed Central

    2014-01-01

    The self-assembly of individual nanoparticles into dimers—so-called heterodimers—is relevant for a broad range of applications, in particular in the vibrant field of nanoplasmonics and nanooptics. In this paper we report the synthesis and characterization of material- and shape-selected nanoparticle heterodimers assembled from individual particles via electrostatic interaction. The versatility of the synthetic strategy is shown by assembling combinations of metal particles of different shapes, sizes, and metal compositions like a gold sphere (90 nm) with either a gold cube (35 nm), gold rhombic dodecahedron (50 nm), palladium truncated cube (120 nm), palladium rhombic dodecahedron (110 nm), palladium octahedron (130 nm), or palladium cubes (25 and 70 nm) as well as a silver sphere (90 nm) with palladium cubes (25 and 70 nm). The obtained heterodimer combinations are characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), scanning transmission electron microscopy–energy dispersive X-ray spectroscopy (STEM-EDX), dynamic light scattering (DLS), and zeta-potential measurements. We describe the optimal experimental conditions to achieve the highest yield of heterodimers compared to other aggregates. The experimental results have been rationalized using theoretical modeling. A proof-of-principle experiment where individual Au–Pd heterodimers are exploited for indirect plasmonic sensing of hydrogen finally illustrates the potential of these structures to probe catalytic processes at the single particle level. PMID:24580549

  3. A heterodimer of human 3'-phospho-adenosine-5'-phosphosulphate (PAPS) synthases is a new sulphate activating complex

    SciTech Connect

    Grum, Daniel; Boom, Johannes van den; Neumann, Daniel; Matena, Anja; Link, Nina M.; Mueller, Jonathan W.

    2010-05-07

    3'-Phospho-adenosine-5'-phosphosulphate (PAPS) synthases are fundamental to mammalian sulphate metabolism. These enzymes have recently been linked to a rising number of human diseases. Despite many studies, it is not yet understood how the mammalian PAPS synthases 1 and 2 interact with each other. We provide first evidence for heterodimerisation of these two enzymes by pull-down assays and Foerster resonance energy transfer (FRET) measurements. Kinetics of dimer dissociation/association indicates that these heterodimers form as soon as PAPSS1 and -S2 encounter each other in solution. Affinity of the homo- and heterodimers were found to be in the low nanomolar range using anisotropy measurements employing proteins labelled with the fluorescent dye IAEDANS that - in spite of its low quantum yield - is well suited for anisotropy due to its large Stokes shift. Within its kinase domain, the PAPS synthase heterodimer displays similar substrate inhibition by adenosine-5'-phosphosulphate (APS) as the homodimers. Due to divergent catalytic efficacies of PAPSS1 and -S2, the heterodimer might be a way of regulating PAPS synthase function within mammalian cells.

  4. The proportion of hybrid heterodimers in homozygous or doubly heterozygous beta chain variant hemoglobinopathies associated with alpha chain hemoglobin variants.

    PubMed

    Krauss, J S

    2000-10-01

    Four alpha genes exist on chromosome 16, but one or more of these genes can be deleted in association with Hemoglobin (Hb)G-Philadelphia in cis to alpha-thalassemia-2 in African-Americans. Therefore, the proportion of HbG-Philadelphia in HbG heterozygotes is trimodal at about 25% for alphaGalpha/alpha alpha, 33% for alphaG-/alpha alpha, and 50% for alphaG-/alpha alpha in patients with HbA. Those who are homozygous or doubly heterozygous for beta chain variants (betaX2 or betaXbetaY) have neither HbA nor the alpha chain variant (alphaX2 betaA2), but have hybrid heterodimers (alphaX2 betaX2). The proportion of hybrid heterodimers here should also be trimodal mirroring alpha gene status. Eleven patients were identified: 4 with Hb SSG, 3 with Hb SCG, and 1 each with Hb OCG, HbSSMontgomery, HbSSChicago, and HbSSBourmedes. Heterodimer proportions were: 43.3 +/- 1.5, 33.5 +/- 2.3, and 15.8 +/- 1.1% for 2, 3, and 4 respective alpha genes which had been studied in 8/11 of the patients (r = 0.98), implying that the prime determinant of the proportion of hybrid heterodimers in this patient group is the number of functional alpha genes. PMID:11045763

  5. Recognition of Borrelia burgdorferi by NOD2 is central for the induction of an inflammatory reaction.

    PubMed

    Oosting, Marije; Berende, Anneleen; Sturm, Patrick; Ter Hofstede, Hadewych J M; de Jong, Dirk J; Kanneganti, Thirumala-Devi; van der Meer, Jos W M; Kullberg, Bart-Jan; Netea, Mihai G; Joosten, Leo A B

    2010-06-15

    Toll-like receptor 2 (TLR2) plays an important role in the recognition of Borrelia bacteria, the causative agent of Lyme disease, but the existence and importance of additional receptors in this process has been hypothesized. In the present study, we confirmed the role played by TLR2 in the recognition of Borrelia bacteria but also demonstrated a crucial role for the intracellular peptidoglycan receptor NOD2 for sensing the spirochete. Cells from individuals who were homozygous for the loss-of-function mutation 3020insC in the NOD2 gene were defective with respect to cytokine release after stimulation with Borrelia species, and this was confirmed in peritoneal macrophages from mice lacking RICK, the adaptor molecule used by NOD2. In contrast, NOD1 played no major role in the recognition of Borrelia spirochetes. This raises the intriguing possibility that recognition of Borrelia spirochetes is exerted by TLR2 in combination with NOD2 and that both receptors are necessary for an effective induction of cytokines by Borrelia species. The interplay between TLR2 and NOD2 might not only be necessary for the induction of a proper immune response but may also contribute to inflammatory-induced pathology. PMID:20441518

  6. Sylvatic maintenance of Borrelia burgdorferi (Spirochaetales) in Northern California: untangling the web of transmission.

    PubMed

    Brown, R N; Peot, M A; Lane, R S

    2006-07-01

    Lyme borreliosis is associated with several genospecies of Borrelia burgdorferi sensu lato (s.l.) (Spirochaetales), but human disease has been associated only with Borrelia burgdorferi sensu stricto (s.s.) Johnson, Schmid, Hyde, Steigerwalt & Brenner in the western United States. Restriction fragment length polymorphism (RFLP) analysis of rrf-rrl amplicons from 124 tick and mammalian isolates from various habitats yielded 13 RFLP patterns. Of these patterns, six were patterns previously associated either with Borrelia bissettii Postic, Marti Ras, Lane, Hendson & Baranton or Borrelia burgdorferi s.s., and the remaining seven patterns belonged to diverse and previously uncharacterized Borrelia spp. Uncharacterized Borrelia spp. were cultured most frequently from Ixodes spinipalpis Hadwen & Nuttall and California kangaroo rats, Dipodomys californicus Merriam, inhabiting grasslands, and B. bissettii from I. spinipalpis and dusky-footed woodrats, Neotoma fuscipes Baird, associated with oak woodlands or chaparral. B. burgdorferi s.s. typically was isolated from host-seeking Ixodes pacificus Cooley & Kohls collected in dense oak woodlands, woodland-grass, or redwood forests. Although some isolates of B. burgdorferi s.s. were cultured from woodrats, there was no clear association of this human pathogen with any vertebrate host. These findings, along with recent evidence indicating that the western gray squirrel, Sciurus griseus Ord, may be an important reservoir of B. burgdorferi s.s. in Californian oak woodlands, suggest that our earlier hypothesis implicating an enzootic cycle involving woodrats and I. spinipalpis is insufficient to account for observed patterns of infection in nature. PMID:16892634

  7. Transovarial transmission of Borrelia spirochetes by Ixodes scapularis: a summary of the literature and recent observations.

    PubMed

    Rollend, Lindsay; Fish, Durland; Childs, James E

    2013-02-01

    Transovarial transmission (TOT) of Borrelia burgdorferi (sensu lato), the agent of Lyme disease, by the Ixodes persulcatus group of hard ticks (Ixodidae) has frequently been reported in the literature since the discovery of Lyme disease 1982. Evidence for and against TOT by B. burgdorferi has led to uncertainty and confusion in the literature, causing misconceptions that may have public health consequences. In this report, we review the published information implicating B. burgdorferi as a bacterium transovarially transmitted among ticks of the Ixodes persulcatus group and present new data indicating the transovarially transmitted agent is actually Borrelia miyamotoi. B. miyamotoi, first described in 1995, is antigenically and phylogenetically related to B. burgdorferi, although more closely related to the relapsing fever-group Borrelia typically transmitted by soft ticks (Argasidae). Borrelia infections of unfed larvae derived from egg clutches of wild-caught Ixodes scapularis are demonstrated to result from transovarial transmission of B. miyamotoi, not B. burgdorferi. The presence of this second Borrelia species, apparently sympatric with B. burgdorferi worldwide also may explain other confusing observations reported on Borrelia/Ixodes relationships. PMID:23238242

  8. Heterodimers and homodimers of inhibin subunits have different paracrine action in the modulation of luteinizing hormone-stimulated androgen biosynthesis.

    PubMed Central

    Hsueh, A J; Dahl, K D; Vaughan, J; Tucker, E; Rivier, J; Bardin, C W; Vale, W

    1987-01-01

    Inhibin, a gonadal hormone capable of preferential suppression of pituitary follicle-stimulating hormone (FSH) secretion, has recently been purified. The major form of this protein is an alpha beta heterodimer encoded by two separate genes. In contrast to the FSH-suppressing action of the alpha beta heterodimer, the beta beta homodimer stimulates FSH secretion. Luteinizing hormone (LH)-secreting pituitary cells and gonadal androgen-producing cells have long been shown to form a closed-loop feedback axis. Based on recent studies demonstrating the FSH stimulation of inhibin biosynthesis by ovarian granulosa and testis Sertoli cells, an additional closed-loop feedback axis exists between pituitary FSH- and gonadal inhibin-producing cells. Because uncharacterized Sertoli cell factors have been suggested to either stimulate or inhibit androgen production by testicular Leydig cells, we have tested the intragonadal paracrine actions of heterodimers and homodimers of inhibin subunits. In primary cultures of testis cells, the alpha beta heterodimer of inhibin enhances Leydig cell androgen biosynthesis stimulated by LH, whereas the beta beta homodimer suppresses androgen production. Furthermore, similar modulatory actions of inhibin-related proteins were found in cultured ovarian theca-interstitial cells and theca explants treated with LH. In contrast, treatment with the inhibin-related proteins alone did not affect gonadal steroidogenesis. Our data indicate that the inhibin-related gene products synthesized by Sertoli and granulosa cells may form heterodimers or homodimers to serve as intragonadal paracrine signals in the modulation of LH-stimulated androgen biosynthesis and allow cross-communication between the two feedback loops. PMID:3474640

  9. BB0744 Affects Tissue Tropism and Spatial Distribution of Borrelia burgdorferi.

    PubMed

    Wager, Beau; Shaw, Dana K; Groshong, Ashley M; Blevins, Jon S; Skare, Jon T

    2015-09-01

    Borrelia burgdorferi, the etiologic agent of Lyme disease, produces a variety of proteins that promote survival and colonization in both the Ixodes species vector and various mammalian hosts. We initially identified BB0744 (also known as p83/100) by screening for B. burgdorferi strain B31 proteins that bind to α1β1 integrin and hypothesized that, given the presence of a signal peptide, BB0744 may be a surface-exposed protein. In contrast to this expectation, localization studies suggested that BB0744 resides in the periplasm. Despite its subsurface location, we were interested in testing whether BB0744 is required for borrelial pathogenesis. To this end, a bb0744 deletion was isolated in a B. burgdorferi strain B31 infectious background, complemented, and queried for the role of BB0744 following experimental infection. A combination of bioluminescent imaging, cultivation of infected tissues, and quantitative PCR (qPCR) demonstrated that Δbb0744 mutant B. burgdorferi bacteria were attenuated in the ability to colonize heart tissue, as well as skin locations distal to the site of infection. Furthermore, qPCR indicated a significantly reduced spirochetal load in distal skin and joint tissue infected with Δbb0744 mutant B. burgdorferi. Complementation with bb0744 restored infectivity, indicating that the defect seen in Δbb0744 mutant B. burgdorferi was due to the loss of BB0744. Taken together, these results suggest that BB0744 is necessary for tissue tropism, particularly in heart tissue, alters the ability of B. burgdorferi to disseminate efficiently, or both. Additional studies are warranted to address the mechanism employed by BB0744 that alters the pathogenic potential of B. burgdorferi. PMID:26150534

  10. BB0744 Affects Tissue Tropism and Spatial Distribution of Borrelia burgdorferi

    PubMed Central

    Wager, Beau; Shaw, Dana K.; Groshong, Ashley M.; Blevins, Jon S.

    2015-01-01

    Borrelia burgdorferi, the etiologic agent of Lyme disease, produces a variety of proteins that promote survival and colonization in both the Ixodes species vector and various mammalian hosts. We initially identified BB0744 (also known as p83/100) by screening for B. burgdorferi strain B31 proteins that bind to α1β1 integrin and hypothesized that, given the presence of a signal peptide, BB0744 may be a surface-exposed protein. In contrast to this expectation, localization studies suggested that BB0744 resides in the periplasm. Despite its subsurface location, we were interested in testing whether BB0744 is required for borrelial pathogenesis. To this end, a bb0744 deletion was isolated in a B. burgdorferi strain B31 infectious background, complemented, and queried for the role of BB0744 following experimental infection. A combination of bioluminescent imaging, cultivation of infected tissues, and quantitative PCR (qPCR) demonstrated that Δbb0744 mutant B. burgdorferi bacteria were attenuated in the ability to colonize heart tissue, as well as skin locations distal to the site of infection. Furthermore, qPCR indicated a significantly reduced spirochetal load in distal skin and joint tissue infected with Δbb0744 mutant B. burgdorferi. Complementation with bb0744 restored infectivity, indicating that the defect seen in Δbb0744 mutant B. burgdorferi was due to the loss of BB0744. Taken together, these results suggest that BB0744 is necessary for tissue tropism, particularly in heart tissue, alters the ability of B. burgdorferi to disseminate efficiently, or both. Additional studies are warranted to address the mechanism employed by BB0744 that alters the pathogenic potential of B. burgdorferi. PMID:26150534

  11. Molecular identification of Borrelia genus in questing hard ticks from Portugal: Phylogenetic characterization of two novel Relapsing Fever-like Borrelia sp.

    PubMed

    Nunes, Mónica; Parreira, Ricardo; Maia, Carla; Lopes, Nádia; Fingerle, Volker; Vieira, M Luísa

    2016-06-01

    In the last decades, several studies have reported pathogenic species of Borrelia related to those that cause Tick-borne Relapsing Fever (RF), but unexpectedly suggesting their transmission by hard ticks, known vectors of Borrelia burgdorferi sensu lato (B. burgdorferi s.l.) species, rather than by soft ticks. This study was designed to update the presence of B. burgdorferi s.l. species in ticks from several districts of mainland Portugal, where Ixodes ricinus had been previously described. Ticks (a total of 2915 specimens) were collected in seven districts throughout the country, and analyzed using molecular methods. Three nested-PCR protocols, targeting the flagellin gene (flaB), the intergenic spacer region (IGS) located between 5S and 23S rRNA, and the glpQ gene, and a conventional PCR targeting the 16S rRNA, were used for Borrelia DNA detection. Borrelia DNA was detected in 3% of the ticks from Braga, Vila Real, Lisboa, Setúbal, Évora and Faro districts. The obtained amplicons were sequenced and analyzed by BLASTn, and 15/63 (24%) matched with homologous sequences from Borrelia lusitaniae and 15/63 (24%) with B. garinii, being these the most prevalent species. DNA from B. burgdorferi sensu stricto (s.s.), B. valaisiana and B. afzelii were detected in 7/63 (11%), 6/63 (10%), and 2/63 (3%) of the specimens, respectively. Unexpectedly, DNA sequence (flaB) analysis from eight (13%) samples, two from Rhipicephalus sanguineus and six from Haemaphysalis punctata tick species, revealed high homology with RF-like Borrelia. Phylogenetic analyses obtained from three genetic markers (16S rRNA, flaB, and glpQ) confirmed their congruent inclusion in a strongly supported RF cluster, where they segregated in two subgroups which differ from the other Relapsing Fever species. Therefore, the results confirm the circulation of multiple species of B. burgdorferi s.l. over a wide geographic range, covering most of the Portuguese mainland territory. Surprisingly, the obtained data

  12. Enhancement of Borrelia burgdorferi PCR by uracil N-glycosylase.

    PubMed Central

    Loewy, Z G; Mecca, J; Diaco, R

    1994-01-01

    Uracil DNA glycosylases are DNA repair enzymes present in virtually every organism. These enzymes function by excising from DNA uracil residues resulting from either misincorporation of dUMP residues by a DNA polymerase or deamination of cytosine. Recently, the enzyme has been exploited in PCRs as a means for controlling carryover contamination from previously amplified DNA. When the enzyme is used in amplifications of Borrelia burgdorferi target sequences, we have observed an enhancement in signal detected by a microwell plate DNA hybridization assay. This increase in signal is dependent upon the length of the target, is titratable with enzyme concentration, and has been observed with amplifications performed with both symmetric and asymmetric PCR profiles. The enhancement is shown to occur at the level of the target genomic DNA. PMID:8126168

  13. Persister Development by Borrelia burgdorferi Populations In Vitro.

    PubMed

    Caskey, John R; Embers, Monica E

    2015-10-01

    Doxycycline is an antibiotic commonly used to treat Lyme disease and other bacterial infections. The MIC and minimum bactericidal concentration (MBC) for Borrelia burgdorferi have been investigated by different groups but were experimentally established in this study as a function of input cell density. We demonstrated that B. burgdorferi treated in the stationary phase has a higher probability of regrowth following removal of antibiotic. In addition, we determined experimentally and mathematically that the spirochetes which persist posttreatment do not have a longer lag phase but exhibit a lower growth rate than untreated spirochetes. Finally, we found that treating the spirochetes by pulse-dosing did not eliminate growth or reduce the persister population in vitro. From these data, we propose that B. burgdorferi persister development is stochastic and driven by slowed growth. PMID:26248368

  14. Molecular Identification of Borrelia miyamotoi in Ixodes ricinus from Portugal.

    PubMed

    Nunes, Mónica; Parreira, Ricardo; Lopes, Nádia; Maia, Carla; Carreira, Teresa; Sousa, Carmelita; Faria, Sofia; Campino, Lenea; Vieira, M Luísa

    2015-08-01

    Borrelia miyamotoi, a relapsing fever spirochete, has been found recently in Ixodes ricinus ticks; however, little is known about its spatial distribution and potential local impact on human health. A total of 640 ticks (447 nymphs and 193 adults) collected throughout Portugal were analyzed using two nested PCR protocols, one targeting the flagellin gene and the other the internal transcribed space region between the 5S and the 23S rRNA. As a result, B. miyamotoi was detected, for the first time, in one guesting I. ricinus nymph collected in the Lisboa district. In addition, a prevalence of 11% (71/640) for B. burgdorferi sensu lato was obtained. Even though no human relapsing fever cases due to infection by B. miyamotoi have been reported yet in Portugal, surveillance must be improved to provide better insight into the prevalence and distribution of this spirochete in ticks. PMID:26273814

  15. Lipid Exchange between Borrelia burgdorferi and Host Cells

    PubMed Central

    Crowley, Jameson T.; Toledo, Alvaro M.; LaRocca, Timothy J.; Coleman, James L.; London, Erwin; Benach, Jorge L.

    2013-01-01

    Borrelia burgdorferi, the agent of Lyme disease, has cholesterol and cholesterol-glycolipids that are essential for bacterial fitness, are antigenic, and could be important in mediating interactions with cells of the eukaryotic host. We show that the spirochetes can acquire cholesterol from plasma membranes of epithelial cells. In addition, through fluorescent and confocal microscopy combined with biochemical approaches, we demonstrated that B. burgdorferi labeled with the fluorescent cholesterol analog BODIPY-cholesterol or 3H-labeled cholesterol transfer both cholesterol and cholesterol-glycolipids to HeLa cells. The transfer occurs through two different mechanisms, by direct contact between the bacteria and eukaryotic cell and/or through release of outer membrane vesicles. Thus, two-way lipid exchange between spirochetes and host cells can occur. This lipid exchange could be an important process that contributes to the pathogenesis of Lyme disease. PMID:23326230

  16. Bullying Borrelia: when the culture of science is under attack.

    PubMed

    Auwaerter, Paul G; Melia, Michael T

    2012-01-01

    Although Lyme disease responds to short courses of antibiotics, tick-borne Borrelia burgdorferi has been advanced by some as a frequent explanation for medically unexplained symptoms such as continual fatigue, musculoskeletal pains, and subjective neurocognitive dysfunction. Often called "chronic Lyme disease" by adherents of this philosophy, it is loosely defined, and practitioners liberally prescribe nostrums, including prolonged antimicrobial therapies, in a belief that this eradicates suspected infection. Perhaps due to the lack of supportive data, proponents of this theory have developed their own meetings, literature, activist groups, and substantial internet activities to advance their views. Forces motivating this movement are explored, as are tactics used to advance non-scientific ideas that have included legal action and garnering legislative endorsement. While neither logical nor evidence-based, "chronic Lyme disease" harnesses corrosive energies that taint modern medicine and society. PMID:23303970

  17. Susceptibility of selected rodent species from Colorado to Borrelia burgdorferi.

    PubMed

    Ubico, S R; McLean, R G; Cooksey, L M

    1996-04-01

    To determine the susceptibility of some common Colorado (USA) rodent species to Borrelia burgdorferi, pregnant Peromyscus maniculatus, Tamias minimus, and Spermophilus lateralis were trapped in May 1990 and kept in quarantine until their young were old enough to be used in the experiment. Six to eight 8-wk-old individuals of each of the Colorado species and, for comparison, eight laboratory raised P. leucopus were subcutaneously inoculated with > or = 10(5) spirochetes in 0.1 ml in July 1990. Tissue specimens were collected for isolation from these animals through April 1991. Spirochetes were isolated from blood, ear, bladder, kidney, spleen, liver, and eye in Barbour-Stoener-Kelly (BSK) medium from P. maniculatus, P. leucopus and T. minimus. Spirochetes were isolated from at least one tissue from all of these animals and no isolations were obtained from any of the S. lateralis. Thus, three of the four rodent species tested are susceptible to, and could harbor, B. burgdorferi. PMID:8722268

  18. Borrelia burgdorferi infection and Lyme disease in children.

    PubMed

    Esposito, Susanna; Bosis, Samantha; Sabatini, Caterina; Tagliaferri, Laura; Principi, Nicola

    2013-03-01

    Lyme disease is a multisystem disease that frequently affects children. It is caused by a group of related spirochetes, Borrelia burgdorferi sensu lato, that are transmitted by ticks belonging to species of the genus Ixodes. The clinical characteristics of Lyme disease in pediatrics resemble those observed in adults, although the symptoms may last for a shorter time and the outcome may be better. However, identifying Lyme disease in children can be significantly more difficult because some of its signs and symptoms can be similar to those of other common pediatric clinical manifestations. Finally, the diagnostic and therapeutic approach to childhood Lyme disease is frequently not codified, and guidelines specifically prepared for adults are used for children without having been validated. This review of the currently available data will evaluate what may be the best approach to the diagnosis and treatment of B. burgdorferi infection and disease in the pediatric population. PMID:23141587

  19. Bullying Borrelia: When the Culture of Science is Under Attack

    PubMed Central

    Auwaerter, Paul G.; Melia, Michael T.

    2012-01-01

    Although Lyme disease responds to short courses of antibiotics, tick-borne Borrelia burgdorferi has been advanced by some as a frequent explanation for medically unexplained symptoms such as continual fatigue, musculoskeletal pains, and subjective neurocognitive dysfunction. Often called “chronic Lyme disease” by adherents of this philosophy, it is loosely defined, and practitioners liberally prescribe nostrums, including prolonged antimicrobial therapies, in a belief that this eradicates suspected infection. Perhaps due to the lack of supportive data, proponents of this theory have developed their own meetings, literature, activist groups, and substantial internet activities to advance their views. Forces motivating this movement are explored, as are tactics used to advance non-scientific ideas that have included legal action and garnering legislative endorsement. While neither logical nor evidence-based, “chronic Lyme disease” harnesses corrosive energies that taint modern medicine and society. PMID:23303970

  20. Nanoscopic Localization of Surface-Exposed Antigens of Borrelia burgdorferi.

    PubMed

    Lemgruber, Leandro; Sant'Anna, Celso; Griffths, Caron; Abud, Yuri; Mhlanga, Musa; Wallich, Reinhard; Frischknecht, Friedrich

    2015-06-01

    Borrelia burgdorferi sensu lato, the causative agent of Lyme disease, is transmitted to humans through the bite of infected Ixodes spp. ticks. Successful infection of vertebrate hosts necessitates sophisticated means of the pathogen to escape the vertebrates' immune system. One strategy employed by Lyme disease spirochetes to evade adaptive immunity involves a highly coordinated regulation of the expression of outer surface proteins that is vital for infection, dissemination, and persistence. Here we characterized the expression pattern of bacterial surface antigens using different microscopy techniques, from fluorescent wide field to super-resolution and immunogold-scanning electron microscopy. A fluorescent strain of B. burgdorferi spirochetes was labeled with monoclonal antibodies directed against various bacterial surface antigens. Our results indicate that OspA is more evenly distributed over the surface than OspB and OspC that were present as punctate areas. PMID:25739645

  1. Borrelia burgdorferi mutant lacking Osp: biological and immunological characterization.

    PubMed Central

    Sadziene, A; Thomas, D D; Barbour, A G

    1995-01-01

    All Borrelia burgdorferi sensu lato isolates characterized to date have one or a combination of several major outer surface proteins (Osps). Mutants of B. burgdorferi lacking Osps were selected with polyclonal or monoclonal antibodies at a frequency of 10(-6) to 10(-5). One mutant that lacked OspA, -B, -C, and -D was further characterized. It was distinguished from the OspA+B+ cells by its (i) autoaggregation and slower growth rate, (ii) decreased plating efficiency on solid medium, (iii) serum and complement sensitivity, and (iv) diminished capacity to adhere to human umbilical vein endothelial cells. The Osp-less mutant was unable to evoke a detectable immune response after intradermal live cell immunization even though mutant survived in mouse skin for the same duration as wild-type cells. Polyclonal mouse serum raised against Osp-less cells inhibited growth of the mutant but not of wild-type cells, an indication that other antigens are present on the surface of the Osp-less mutant. Two types of monoclonal antibodies (MAbs) with growth-inhibiting properties for mutant cells were identified. The first type bound to a 13-kDa surface protein of B. burgdorferi sensu stricto and of B. afzelii. The MIC of the Fab fragment of one MAb of this type was 0.2 micrograms/ml. The second type of MAb to the Osp-less mutant did not bind to B. burgdorferi components by Western blotting (immunoblotting) but did not bind to unfixed, viable cells in immunofluorescence and growth inhibition assays. These studies revealed possible functions Osp proteins in borrelias, specifically serum resistance, and indicated that in the absence of Osp proteins, other antigens are expressed or become accessible at the cell surface. PMID:7890424

  2. Borrelia miyamotoi Infection in Nature and in Humans

    PubMed Central

    Krause, Peter J.; Fish, Durland; Narasimhan, Sukanya; Barbour, Alan G.

    2015-01-01

    Borrelia miyamotoi is a relapsing fever Borrelia group spirochete that is transmitted by the same hard-bodied (ixodid) tick species that transmit the agents of Lyme disease. It was discovered in 1994 in Ixodes persulcatus ticks in Japan. B. miyamotoi species phylogenetically cluster with the relapsing fever group spirochetes, which usually are transmitted by soft-bodied (argasid) ticks or lice. B. miyamotoi infects at least six Ixodes tick species in North America and Eurasia that transmit Lyme disease group spirochetes and may use small rodents and birds as reservoirs. Human cases of B. miyamotoi infection were first reported in 2011 in Russia and subsequently in the United States, Europe, and Japan. These reports document the public health importance of B. miyamotoi, as human B. miyamotoi infection appears to be comparable in frequency to babesiosis or human granulocytic anaplasmosis in some areas and may cause severe disease, including meningoencephalitis. The most common clinical manifestations of B. miyamotoi infection are fever, fatigue, headache, chills, myalgia, arthralgia, and nausea. Symptoms of B. miyamotoi infection generally resolve within a week of the start of antibiotic therapy. B. miyamotoi infection should be considered in patients with acute febrile illness who have been exposed to Ixodes ticks in a region where Lyme disease occurs. Because clinical manifestations are non-specific, etiologic diagnosis requires confirmation by blood smear examination, PCR, antibody assay, in vitro cultivation, and/or isolation by animal inoculation. Antibiotics that have been used effectively include doxycycline for uncomplicated B. miyamotoi infection in adults and ceftriaxone or penicillin G for meningoencephalitis. PMID:25700888

  3. Transmission Dynamics of Borrelia turicatae from the Arthropod Vector

    PubMed Central

    Boyle, William K.; Wilder, Hannah K.; Lawrence, Amanda M.; Lopez, Job E.

    2014-01-01

    Background With the global distribution, morbidity, and mortality associated with tick and louse-borne relapsing fever spirochetes, it is important to understand the dynamics of vector colonization by the bacteria and transmission to the host. Tick-borne relapsing fever spirochetes are blood-borne pathogens transmitted through the saliva of soft ticks, yet little is known about the transmission capability of these pathogens during the relatively short bloodmeal. This study was therefore initiated to understand the transmission dynamics of the relapsing fever spirochete Borrelia turicatae from the vector Ornithodoros turicata, and the subsequent dissemination of the bacteria upon entry into murine blood. Methodology/Principal Findings To determine the minimum number of ticks required to transmit spirochetes, one to three infected O. turicata were allowed to feed to repletion on individual mice. Murine infection and dissemination of the spirochetes was evaluated by dark field microscopy of blood, quantitative PCR, and immunoblotting against B. turicatae protein lysates and a recombinant antigen, the Borrelia immunogenic protein A. Transmission frequencies were also determined by interrupting the bloodmeal 15 seconds after tick attachment. Scanning electron microscopy (SEM) was performed on infected salivary glands to detect spirochetes within acini lumen and excretory ducts. Furthermore, spirochete colonization and dissemination from the bite site was investigated by feeding infected O. turicata on the ears of mice, removing the attachment site after engorment, and evaluating murine infection. Conclusion/Significance Our findings demonstrated that three ticks provided a sufficient infectious dose to infect nearly all animals, and B. turicatae was transmitted within seconds of tick attachment. Spirochetes were also detected in acini lumen of salivary glands by SEM. Upon host entry, B. turicatae did not require colonization of the bite site to establish murine

  4. Discovery and Targeted Proteomics on Cutaneous Biopsies Infected by Borrelia to Investigate Lyme Disease*

    PubMed Central

    Schnell, Gilles; Boeuf, Amandine; Westermann, Benoît; Jaulhac, Benoît; Lipsker, Dan; Carapito, Christine; Boulanger, Nathalie; Ehret-Sabatier, Laurence

    2015-01-01

    Lyme disease is the most important vector-borne disease in the Northern hemisphere and represents a major public health challenge with insufficient means of reliable diagnosis. Skin is rarely investigated in proteomics but constitutes in the case of Lyme disease the key interface where the pathogens can enter, persist, and multiply. Therefore, we investigated proteomics on skin samples to detect Borrelia proteins directly in cutaneous biopsies in a robust and specific way. We first set up a discovery gel prefractionation-LC-MS/MS approach on a murine model infected by Borrelia burgdorferi sensu stricto that allowed the identification of 25 Borrelia proteins among more than 1300 mouse proteins. Then we developed a targeted gel prefractionation-LC-selected reaction monitoring (SRM) assay to detect 9/33 Borrelia proteins/peptides in mouse skin tissue samples using heavy labeled synthetic peptides. We successfully transferred this assay from the mouse model to human skin biopsies (naturally infected by Borrelia), and we were able to detect two Borrelia proteins: OspC and flagellin. Considering the extreme variability of OspC, we developed an extended SRM assay to target a large set of variants. This assay afforded the detection of nine peptides belonging to either OspC or flagellin in human skin biopsies. We further shortened the sample preparation and showed that Borrelia is detectable in mouse and human skin biopsies by directly using a liquid digestion followed by LC-SRM analysis without any prefractionation. This study thus shows that a targeted SRM approach is a promising tool for the early direct diagnosis of Lyme disease with high sensitivity (<10 fmol of OspC/mg of human skin biopsy). PMID:25713121

  5. Borrelia-induced cytokine production is mediated by spleen tyrosine kinase (Syk) but is Dectin-1 and Dectin-2 independent.

    PubMed

    Oosting, Marije; Buffen, Kathrin; Cheng, Shih-Chin; Verschueren, Ineke C; Koentgen, Frank; van de Veerdonk, Frank L; Netea, Mihai G; Joosten, Leo A B

    2015-12-01

    Although it is known that Borrelia species express sugar-like structures on their outer surface, not much is known about the role of these structures in immune recognition by host cells. Fungi, like Candida albicans, are mainly recognized by C-type lectin receptors, in specific Dectin-1 and Dectin-2. In this study we assessed the role of Dectin-1 and Dectin-2 in the recognition process of Borrelia spirochetes. Using specific inhibitors against these receptors on human cells did not influenced cytokine production. Individuals carrying a SNP leading to an early stop codon in the DECTIN-1 gene also did not lead to differential induction of Borrelia-dependent cytokines. After injection of live Borrelia into knee joints of Dectin-2 deficient mice a trend towards lower inflammation was observed. Inhibition of Syk in human cells resulted in lower cytokine production after Borrelia stimulation. In conclusion, Dectin-1 and Dectin-2 seem not to play a major role in Borrelia recognition or Borrelia-induced inflammation. However, Syk seems to be involved in Borrelia-induced cytokine production. PMID:26297607

  6. Bile acids inhibit duodenal secretin expression via orphan nuclear receptor small heterodimer partner (SHP).

    PubMed

    Lam, Ian P Y; Lee, Leo T O; Choi, Hueng-Sik; Alpini, Gianfranco; Chow, Billy K C

    2009-07-01

    Small heterodimer partner (SHP) is an orphan nuclear receptor in which gene expression can be upregulated by bile acids. It regulates its target genes by repressing the transcriptional activities of other nuclear receptors including NeuroD, which has been shown to regulate secretin gene expression. Here, we evaluated the regulation on duodenal secretin gene expression by SHP and selected bile acids, cholic acid (CA) and chenodeoxycholic acid (CDCA). In vitro treatment of CDCA or fexaramine elevated the SHP transcript level and occupancy on secretin promoter. The increase in the SHP level, induced by bile acid treatment or overexpression, reduced secretin gene expression, whereas this gene inhibitory effect was reversed by silencing of endogenous SHP. In in vivo studies, double-immunofluorescence staining demonstrated the coexpression of secretin and SHP in mouse duodenum. Feeding mice with 1% CA-enriched rodent chow resulted in upregulation of SHP and a concomitant decrease in secretin transcript and protein levels in duodenum compared with the control group fed with normal chow. A diet enriched with 5% cholestyramine led to a decrease in SHP level and a corresponding increase in secretin expression. Overall, this study showed that bile acids via SHP inhibit duodenal secretin gene expression. Because secretin is a key hormone that stimulates bile flow in cholangiocytes, this pathway thus provides a novel means to modulate secretin-stimulated choleresis in response to intraduodenal bile acids. PMID:19372104

  7. The small heterodimer partner is a gonadal gatekeeper of sexual maturation in male mice

    PubMed Central

    Volle, David H.; Duggavathi, Rajesha; Magnier, Benjamin C.; Houten, Sander M.; Cummins, Carolyn L.; Lobaccaro, Jean-Marc A.; Verhoeven, Guido; Schoonjans, Kristina; Auwerx, Johan

    2007-01-01

    The small heterodimer partner (SHP) is an atypical nuclear receptor known mainly for its role in bile acid homeostasis in the enterohepatic tract. We explore here the role of SHP in the testis. SHP is expressed in the interstitial compartment of the adult testes, which contain the Leydig cells. SHP there inhibits the expression of steroidogenic genes, on the one hand by inhibiting the expression of the nuclear receptors steroidogenic factor-1 and liver receptor homolog-1 (lrh-1), and on the other hand by directly repressing the transcriptional activity of LRH-1. Consequently, in SHP knockout mice, testicular testosterone synthesis is increased independently of the hypothalamus–pituitary axis. Independent of its action on androgen synthesis, SHP also determines the timing of germ cell differentiation by controlling testicular retinoic acid metabolism. Through the inhibition of the transcriptional activity of retinoic acid receptors, SHP controls the expression of stimulated by retinoic acid gene 8 (stra8)—a gene that is indispensable for germ cell meiosis and differentiation. Together, our data demonstrate new roles for SHP in testicular androgen and retinoic acid metabolism, making SHP a testicular gatekeeper of the timing of male sexual maturation. PMID:17289919

  8. Small heterodimer partner interacts with NLRP3 and negatively regulates activation of the NLRP3 inflammasome

    PubMed Central

    Yang, Chul-Su; Kim, Jwa-Jin; Kim, Tae Sung; Lee, Phil Young; Kim, Soo Yeon; Lee, Hye-Mi; Shin, Dong-Min; Nguyen, Loi T.; Lee, Moo-Seung; Jin, Hyo Sun; Kim, Kwang-Kyu; Lee, Chul-Ho; Kim, Myung Hee; Park, Sung Goo; Kim, Jin-Man; Choi, Hueng-Sik; Jo, Eun-Kyeong

    2015-01-01

    Excessive activation of the NLRP3 inflammasome results in damaging inflammation, yet the regulators of this process remain poorly defined. Herein, we show that the orphan nuclear receptor small heterodimer partner (SHP) is a negative regulator of NLRP3 inflammasome activation. NLRP3 inflammasome activation leads to an interaction between SHP and NLRP3, proteins that are both recruited to mitochondria. Overexpression of SHP competitively inhibits binding of NLRP3 to apoptosis-associated speck-like protein containing a CARD (ASC). SHP deficiency results in increased secretion of proinflammatory cytokines IL-1β and IL-18, and excessive pathologic responses typically observed in mouse models of kidney tubular necrosis and peritoneal gout. Notably, the loss of SHP results in accumulation of damaged mitochondria and a sustained interaction between NLRP3 and ASC in the endoplasmic reticulum. These data are suggestive of a role for SHP in controlling NLRP3 inflammasome activation through a mechanism involving interaction with NLRP3 and maintenance of mitochondrial homeostasis. PMID:25655831

  9. The Smc5-Smc6 heterodimer associates with DNA through several independent binding domains

    PubMed Central

    Roy, Marc-André; Dhanaraman, Thillaivillalan; D’Amours, Damien

    2015-01-01

    The Smc5-6 complex is required for the maintenance of genome integrity through its functions in DNA repair and chromosome biogenesis. However, the specific mode of action of Smc5 and Smc6 in these processes remains largely unknown. We previously showed that individual components of the Smc5-Smc6 complex bind strongly to DNA as monomers, despite the absence of a canonical DNA-binding domain (DBD) in these proteins. How heterodimerization of Smc5-6 affects its binding to DNA, and which parts of the SMC molecules confer DNA-binding activity is not known at present. To address this knowledge gap, we characterized the functional domains of the Smc5-6 heterodimer and identify two DBDs in each SMC molecule. The first DBD is located within the SMC hinge region and its adjacent coiled-coil arms, while the second is found in the conserved ATPase head domain. These DBDs can independently recapitulate the substrate preference of the full-length Smc5 and Smc6 proteins. We also show that heterodimerization of full-length proteins specifically increases the affinity of the resulting complex for double-stranded DNA substrates. Collectively, our findings provide critical insights into the structural requirements for effective binding of the Smc5-6 complex to DNA repair substrates in vitro and in live cells. PMID:25984708

  10. Occurrence of Borrelia burgdorferi s.l. in different genera of mosquitoes (Culicidae) in Central Europe.

    PubMed

    Melaun, Christian; Zotzmann, Sina; Santaella, Vanesa Garcia; Werblow, Antje; Zumkowski-Xylander, Helga; Kraiczy, Peter; Klimpel, Sven

    2016-03-01

    Lyme disease or Lyme borreliosis is a vector-borne infectious disease caused by spirochetes of the Borrelia burgdorferi sensu lato complex. Some stages of the borrelial transmission cycle in ticks (transstadial, feeding and co-feeding) can potentially occur also in insects, particularly in mosquitoes. In the present study, adult as well as larval mosquitoes were collected at 42 different geographical locations throughout Germany. This is the first study, in which German mosquitoes were analyzed for the presence of Borrelia spp. Targeting two specific borrelial genes, flaB and ospA encoding for the subunit B of flagellin and the outer surface protein A, the results show that DNA of Borrelia afzelii, Borrelia bavariensis and Borrelia garinii could be detected in ten Culicidae species comprising four distinct genera (Aedes, Culiseta, Culex, and Ochlerotatus). Positive samples also include adult specimens raised in the laboratory from wild-caught larvae indicating that transstadial and/or transovarial transmission might occur within a given mosquito population. PMID:26631488

  11. Differences in binding behavior of (-)-epigallocatechin gallate to β-lactoglobulin heterodimers (AB) compared to homodimers (A) and (B).

    PubMed

    Keppler, Julia K; Martin, Dierk; Garamus, Vasil M; Schwarz, Karin

    2015-11-01

    The lipocalin β-lactoglobulin (β-LG) exists in different natural genetic variants--of which β-LG A and B are predominant in bovine milk. At physiological conditions the protein dimerizes--building homodimers of β-LG A and β-LG B and heterodimers of β-LG AB. Although β-LG is one of the most intensely characterized lipocalins, the interaction behavior of ligands with hetero- and homodimers of β-LG is largely unknown. The present findings revealed significant differences for hetero- and homodimers regarding ligand binding capacity as tested with a model ligand (i.e. surface binding (-)-epigallocatechin gallate (EGCG)). These findings were confirmed using FT-IR, where the addition of EGCG influenced the β-sheet backbone of homodimer A and B with significantly higher intensity compared to heterodimer AB. Further, shape analysis by SAXS revealed oligomerization of both types of dimers upon addition of EGCG; however, homodimer A and B produced significantly larger aggregates compared to the heterodimer AB. In summary, the present study revealed that EGCG showed significantly different interaction reactivity (binding sites, aggregation size and conformational changes) to the hetero and homodimers of β-LG in the order β-LG A > B > AB. The results suggest that conformational differences between homodimers and heterodimers strongly influence the EGCG binding ability. This may also occur with other polyphenols and ligands of β-LG and gives not only important information for β-LG binding studies, but may also apply for polymorphisms of other self-aggregating lipocalins. PMID:26038095

  12. The enzyme engineering of mutant homodimer and heterodimer of coproporphyinogen oxidase contributes to new insight into hereditary coproporphyria and harderoporphyria.

    PubMed

    Kim, Dao Hoang Thien; Hino, Ryoko; Adachi, Yuka; Kobori, Akio; Taketani, Shigeru

    2013-12-01

    Hereditary coproporphyria (HCP) is an autosomal dominant-inherited disease of haem biosynthesis caused by partial deficiency of the enzyme coproporphyrinogen oxidase (CPOX). Patients with HCP show <50% of normal activity and those with the rare autosomal recessive harderoporphyria accumulate harderoporphyrinogen, an intermediate porphyrin of the CPOX reaction. To clarify the relationship of the low enzyme activity with these diseases, we expressed mutant CPOX carrying His-tag from these porphyria patients and co-expressed mutant CPOX carrying His-tag and normal CPOX carrying HA-tag in a tandem fashion in Escherichia coli. Purification of the His-tag-containing enzyme revealed that the His-enzyme forms a heterodimer in association with the HA-enzyme, and analysis using a cross-link reagent confirmed that the enzyme is a dimer (∼70 kDa). Then, we expressed homo- and heterodimers composed of the wild-type (wt) and engineered mutants of the enzyme or mutants from HCP patients. The monomer form of mutated CPOX did not show any activity and homodimeric enzymes derived from HCP mutant showed low activity (<20% of the control). Some mutations of amino acids 401-404 were associated with marked accumulation of harderoporphyrinogen, with a decrease in the production of protoporphyrinogen, whereas K404E derived from patients with harderoporphyria produced less harderoporphyrinogen. The heterodimers with wt and mutated subunits from HCP patients showed low protoporphyrinogen producing activity. These results show that the substitution of amino acids from R401 to K404 results in extremely low enzyme activity with either mutant homodimer or heterodimers containing normal and mutated subunits and can be linked to HCP disease. PMID:24078084

  13. Two CheW coupling proteins are essential in a chemosensory pathway of Borrelia burgdorferi

    PubMed Central

    Zhang, Kai; Liu, Jun; Tu, Youbin; Xu, Hongbin; Charon, Nyles W.; Li, Chunhao

    2012-01-01

    SUMMARY In the model organism Escherichia coli, the coupling protein CheW, which bridges the chemoreceptors and histidine kinase CheA, is essential for chemotaxis. Unlike the situation in E. coli, Borrelia burgdorferi, the causative agent of Lyme disease, has three cheW homologues (cheW1, cheW2, and cheW3). Here, a comprehensive approach is utilized to investigate the roles of the three cheWs in chemotaxis of B. burgdorferi. First, genetic studies indicated that both the cheW1 and cheW3 genes are essential for chemotaxis, as the mutants had altered swimming behaviors and were non-chemotactic. Second, immunofluorescence and cryo-electron tomography studies suggested that both CheW1 and CheW3 are involved in the assembly of chemoreceptor arrays at the cell poles. In contrast to cheW1 and cheW3, cheW2 is dispensable for chemotaxis and assembly of the chemoreceptor arrays. Finally, immunoprecipitation studies demonstrated that the three CheWs interact with different CheAs: CheW1 and CheW3 interact with CheA2 whereas CheW2 binds to CheA1. Collectively, our results indicate that CheW1 and CheW3 are incorporated into one chemosensory pathway that is essential for B. burgdorferi chemotaxis. Although many bacteria have more than one homologue of CheW, to our knowledge, this report provides the first experimental evidence that two CheW proteins co-exist in one chemosensory pathway and that both are essential for chemotaxis. PMID:22780444

  14. Endophilin B2 promotes inner mitochondrial membrane degradation by forming heterodimers with Endophilin B1 during mitophagy

    PubMed Central

    Wang, Yi-Han; Wang, Jiu-Qiang; Wang, Qiaochu; Wang, Yun; Guo, Caixia; Chen, Quan; Chai, Tuanyao; Tang, Tie-Shan

    2016-01-01

    Mitochondrial sequestration by autophagosomes is a key step in mitophagy while the mechanisms mediating this process are not fully understood. It has been reported that Endophilin B1 (EB1) promotes mitochondrial sequestration by binding and shaping membrane. However, the role of EB1 homolog Endophilin B2 (EB2) in mitophagy remains unclear. Here we report that EB2 plays an indispensable role in mitochondria sequestration and inner mitochondrial membrane (IMM) protein degradation during mitophagy. Similar to EB1, EB2 aggregates into foci and then translocates to damaged mitochondria. Loss of either EB2 and/or EB1 significantly enervates the foci translocation to fragmented mitochondria and IMM degradation, and the EB1/EB2 heterodimer formed by EB1/EB2 interaction promotes the above process. We noticed that, it is the dimer domain of EB2 but not that of EB1 mediating the heterodimer formation, manifesting the importance of EB2 in mitophagy. Furthermore, we demonstrate that the EB foci formation is closely regulated by the PINK1-Parkin signaling pathway. From these results, we propose that EB1/EB2 heterodimers may serve as linkers between damaged mitochondria and phagophores during mitophagy. PMID:27112121

  15. Effect of heterodimer partner RXR{alpha} on PPAR{gamma} activation function-2 helix in solution

    SciTech Connect

    Lu Jianyun Chen Minghe; Stanley, Susan E.; Li, Ellen

    2008-01-04

    The structural mechanism of allosteric communication between retinoid X receptor (RXR) and its heterodimer partners remains controversial. As a first step towards addressing this question, we report a nuclear magnetic resonance (NMR) study on the GW1929-bound peroxisome proliferator-activated receptor gamma (PPAR{gamma}) ligand-binding domain (LBD) with and without the 9-cis-retinoic acid (9cRA)-bound RXR{alpha} LBD. Sequence-specific {sup 13}C{sup {alpha}}, {sup 13}C{sup {beta}}, and {sup 13}CO resonance assignments have been established for over 95% of the 275 residues in the PPAR{gamma} LBD monomer. The {sup 1}HN, {sup 15}N, and {sup 13}CO chemical shift perturbations induced by the RXR{alpha} LBD binding are located at not only the heterodimer interface that includes the C-terminal residue Y477 but also residues Y473 and K474 in the activation function-2 (AF-2) helix. This result suggests that 9cRA-bound RXR{alpha} can affect the PPAR{gamma} AF-2 helix in solution and demonstrates that NMR is a powerful new tool for studying the mechanism of allosteric ligand activation in RXR heterodimers.

  16. Insights into MHC class I peptide loading from the structure of the Tapasin-ERp57 thiol oxidoreductase heterodimer

    SciTech Connect

    Dong, G.; Wearsch, P.A.; Peaper, D.R.; Cresswell, P.; Reinisch, K.M.

    2009-03-02

    Tapasin is a glycoprotein critical for loading major histocompatibility complex (MHC) class I molecules with high-affinity peptides. It functions within the multimeric peptide-loading complex (PLC) as a disulfide-linked, stable heterodimer with the thiol oxidoreductase ERp57, and this covalent interaction is required to support optimal PLC activity. Here, we present the 2.6 {angstrom} resolution structure of the tapasin-ERp57 core of the PLC. The structure revealed that tapasin interacts with both ERp57 catalytic domains, accounting for the stability of the heterodimer, and provided an example of a protein disulfide isomerase family member interacting with substrate. Mutational analysis identified a conserved surface on tapasin that interacted with MHC class I molecules and was critical for peptide loading and editing functions of the tapasin-ERp57 heterodimer. By combining the tapasin-ERp57 structure with those of other defined PLC components, we present a molecular model that illuminates the processes involved in MHC class I peptide loading.

  17. Requirements for the construction of antibody heterodimers for the direction of lysis of tumors by human T cells.

    PubMed Central

    Scott, C F; Blättler, W A; Lambert, J M; Kalish, R S; Morimoto, C; Schlossman, S F

    1988-01-01

    We constructed a series of MAb heterodimers consisting of the J5 (anti-common acute lymphoblastic leukemia antigen [CALLA]) antibody and antibodies to a variety of structures present on the surface of activated human T cells, including CD3 antigen (T cell receptor-associated glycoproteins), CD2 antigen (T11/E-rosette receptor), CD25 antigen (IL-2 receptor), and the transferrin receptor. We tested the ability of these heterodimers to direct a CD2 + CD3 + CD8 + CD4 - CD25 + transferrin receptor + MHC-restricted human cytolytic T lymphocyte (CTL) clone to lyse a CALLA + human tumor in vitro. Only heterodimers containing an anti-CD3 antibody or activating antibodies to CD2 could direct the clone to lyse these human tumor targets, even when the clone was additionally activated with anti-CD3 or anti-CD2 antibodies. Our findings may have implications in the design of strategies for the use of such reagents in the treatment of human neoplasia. Images PMID:2966815

  18. Nanobody-aided structure determination of the EpsI:EpsJ pseudopilin heterodimer from Vibrio vulnificus

    PubMed Central

    Korotkov, Konstantin V.; Hol, Wim G.J.; Steyaert, Jan

    2014-01-01

    Pseudopilins form the central pseudopilus of the sophisticated bacterial type 2 secretion systems. The crystallization of the EpsI:EpsJ pseudopilin heterodimer from Vibrio vulnificus was greatly accelerated by the use of nanobodies, which are the smallest antigen-binding fragments derived from heavy-chain only camelid antibodies. Seven anti-EpsI:EpsJ nanobodies were generated and co-crystallization of EpsI:EpsJ nano-body complexes yielded several crystal forms very rapidly. In the structure solved, the nanobodies are arranged in planes throughout the crystal lattice, linking layers of EpsI:EpsJ heterodimers. The EpsI:EpsJ dimer observed confirms a right-handed architecture of the pseudopilus, but, compared to a previous structure of the EpsI:EpsJ heterodimer, EpsI differs 6° in orientation with respect to EpsJ; one loop of EpsJ is shifted by ~5 Å due to interactions with the nanobody; and a second loop of EpsJ underwent a major change of 17 Å without contacts with the nanobody. Clearly, nanobodies accelerate dramatically the crystallization of recalcitrant protein complexes and can reveal conformational flexibility not observed before. PMID:19118632

  19. In vitro activities of faropenem, ertapenem, imipenem and meropenem against Borrelia burgdorferi s.l.

    PubMed

    Rödel, Rebecca; Freyer, Alexandra; Bittner, Thomas; Schäfer, Volker; Hunfeld, Klaus-Peter

    2007-07-01

    Little is known about the in vitro activity of penems and carbapenems against the spirochete Borrelia burgdorferi. Here, faropenem, ertapenem, imipenem and meropenem as well as the third-generation cephalosporin ceftriaxone and tobramycin were tested in vitro against 11 isolates of the B. burgdorferi sensu lato complex. On a microg/mL basis, ertapenem was the most potent carbapenem (minimal inhibitory concentration (MIC) range: 0.015-0.125 microg/mL), with in vitro activity comparable with that of ceftriaxone against Borrelia. These findings are supported by the results of time-kill experiments in a Borrelia afzelii skin isolate, demonstrating a >3 log10 unit (99.9%) reduction of the inoculum after 96 h of exposure to either drug at a concentration of three log2 unit dilutions above the respective MIC. PMID:17512703

  20. [Suspected syphilis during pregnancy due to cross reactions in Borrelia infection].

    PubMed

    Enders, G; Biber, M; Baier, R; Hlobil, H; Wellensiek, H J

    1988-09-30

    A weakly positive titre (1:20) in the Treponema pallidum haemagglutination test and a highly positive titre (1:1280) in the fluorescence Treponema antibody absorption test, but negative result for IgM antibodies, were found in the serum of a 23-year-old pregnant woman. The cardiolipin microflocculation test was at first borderline positive, but negative on repeat. In the absence of a history of syphilis tests for Borrelia antibodies were performed. Those for antibodies against B. burgdorferi were highly positive in the ELISA test (550 units), in the indirect Borrelia immunofluorescence test 1:1280 for IgG antibodies and 1:160 for IgM antibodies. In the Borrelia-specific indirect haemagglutination test, which measures both IgG and IgM antibodies, the titres were 1:640 to 1:1280. These results confirmed the presence of an infection with B. burgdorferi and not with Treponema pallidum. PMID:3048959

  1. How do Lyme Borrelia Organisms Cause Disease? The Quest for Virulence Determinants#

    PubMed Central

    Norris, Steven J

    2012-01-01

    Lyme disease Borrelia are invasive, nontoxigenic, persistent pathogens, and little is known about their mechanisms of pathogenesis. In our laboratory, a signature-tagged mutagenesis (STM) library of over 4,000 Borrelia burgdorferi transposon mutants has been constructed and is being screened for infectivity in mice. In this manner, a global view of the virulence determinants (factors required for full infectivity) is being developed. Additionally, the mechanisms of immune evasion involving the VMP-like system (vls) are under analysis, and cryo-electron microscopy is providing a detailed view of the three-dimensional structure of B. burgdorferi. These approaches will contribute to the improved understanding of how Lyme disease Borrelia cause disease. PMID:23091573

  2. The anti-borreliae efficacy of phytochemicals and micronutrients: an update.

    PubMed

    Goc, Anna; Rath, Matthias

    2016-06-01

    Naturally occurring substances have been used for centuries to fight against various pathogens. They serve as a source for new chemical entities or provide options to already existing therapeutics. While there is an increasing interest in studying antimicrobial properties of naturally derived agents, little is known about their effects against Borrelia burgdorferi sensu lato, the causative pathogens of Lyme disease. A better understanding of this aspect could advance knowledge about pathophysiology of these bacteria and help improve the efficacy of current approaches against Lyme disease. Here, we review all naturally occurring substances scientifically evaluated to date, including plant extracts, their metabolites, and micronutrients, against vegetative (spirochetes) and latent (rounded bodies, biofilm) forms of Borrelia sp. This summary reveals the potent anti-borreliae activity of several of these natural compounds indicating their potential in enhancing the efficacy of current treatments for Lyme disease, and offering new options to already existing therapeutic regiments. PMID:27536352

  3. The anti-borreliae efficacy of phytochemicals and micronutrients: an update

    PubMed Central

    Goc, Anna; Rath, Matthias

    2016-01-01

    Naturally occurring substances have been used for centuries to fight against various pathogens. They serve as a source for new chemical entities or provide options to already existing therapeutics. While there is an increasing interest in studying antimicrobial properties of naturally derived agents, little is known about their effects against Borrelia burgdorferi sensu lato, the causative pathogens of Lyme disease. A better understanding of this aspect could advance knowledge about pathophysiology of these bacteria and help improve the efficacy of current approaches against Lyme disease. Here, we review all naturally occurring substances scientifically evaluated to date, including plant extracts, their metabolites, and micronutrients, against vegetative (spirochetes) and latent (rounded bodies, biofilm) forms of Borrelia sp. This summary reveals the potent anti-borreliae activity of several of these natural compounds indicating their potential in enhancing the efficacy of current treatments for Lyme disease, and offering new options to already existing therapeutic regiments. PMID:27536352

  4. Borrelia bavariensis sp. nov. is widely distributed in Europe and Asia.

    PubMed

    Margos, Gabriele; Wilske, Bettina; Sing, Andreas; Hizo-Teufel, Cecilia; Cao, Wu-Chun; Chu, Chenyi; Scholz, Holger; Straubinger, Reinhard K; Fingerle, Volker

    2013-11-01

    Since the original description of Borrelia bavariensis sp. nov. in 2009, additional samples available from humans and ticks from Europe and Mongolia, respectively, have been used to further characterize Borrelia strains belonging to this group of spirochaetes that utilize rodents as reservoir hosts. These investigations suggested the presence of related strains in Europe and Asia and confirmed their status as representing a distinct species. Furthermore, samples that were investigated by researchers from China and Japan confirm the ecological relationship of members of this proposed species with rodents and suggest that it has a wide distribution in Eurasia. Here, we use phylogenetic and genetic distance analyses to validate B. bavariensis sp. nov. as a species within the Borrelia burgdorferi sensu lato species complex. The type strain is PBi(T) ( = DSM 23469(T) = BAA-2496(T)). PMID:23838444

  5. Borrelia infection in small mammals in West Africa and its relationship with tick occurrence inside burrows.

    PubMed

    Diatta, Georges; Duplantier, Jean-Marc; Granjon, Laurent; Bâ, Khalilou; Chauvancy, Gilles; Ndiaye, Mady; Trape, Jean-François

    2015-12-01

    Tick-borne relapsing fever (TBRF) is a zoonotic disease caused by several Borrelia species transmitted to humans by Ornithodoros tick vectors. In West Africa, Borrelia crocidurae is a common cause of disease in many rural populations. Small mammals act as reservoirs of infection. We report here the results of surveys that investigated the occurrence of B. crocidurae infection in rodents and insectivores from eight countries of West and Central Africa. Animals were identified at the species level and tested for Borrelia either by examination of thick blood film, intra-peritoneal inoculation of blood or brain tissues into laboratory mice, or by molecular techniques. A total of 4358 small mammals belonging to 38 species and 7 families were collected, including 3225 specimens collected in areas where the occurrence of Ornithodoros sonrai tick in rodent burrows was documented, and 1133 in areas where this tick was absent. In areas with O. sonrai, Borrelia infection was demonstrated in 287 of 3109 (9.2%) small mammals tested, and none was documented in 1004 animals tested from other areas. There was no relationship between the occurrence of Rhipicephalus, Hyaloma and Argas ticks in burrows and the distribution of Borrelia infection in small mammals. The 287 specimens infected by Borrelia belonged to 15 rodent and shrew species, including three Saharo-Sahelian species - Gerbillus gerbillus, Gerbillus occiduus and Gerbillus tarabuli - identified as reservoirs for TBRF with a distribution restricted to this area. In Sudan and Sudano-Sahelian areas, Arvicanthis niloticus, Mastomys erythroleucus and Mastomys huberti were the main reservoir of infection. Although most small mammals species collected had a large distribution in West and Central Africa, the fact that only animals collected in areas with O. sonrai were found infected suggest that this tick is the only vector of TBRF in rodents and insectivores in this part of Africa. PMID:26327444

  6. The polar 2e/12c bond in phenalenyl-azaphenalenyl hetero-dimers: Stronger stacking interaction and fascinating interlayer charge transfer

    NASA Astrophysics Data System (ADS)

    Zhong, Rong-Lin; Xu, Hong-Liang; Li, Zhi-Ru

    2016-08-01

    An increasing number of chemists have focused on the two-electron/multicenter bond (2e/mc) that was first introduced to interpret the bonding mechanism of radical dimers. Herein, we report the polar two-electron/twelve center (2e/12c) bonding character in a series of phenalenyl-azaphenalenyl radical hetero-dimers. Interestingly, the bonding energy of weaker polar hetero-dimer (P-TAP) is dominated by the overlap of the two different singly occupied molecular orbital of radicals, while that of stronger polar hetero-dimer (P-HAP) is dominated by the electrostatic attraction. Results show that the difference between the electronegativity of the monomers plays a prominent role in the essential attribution of the polar 2e/12c bond. Correspondingly, a stronger stacking interaction in the hetero-dimer could be effectively achieved by increasing the difference of nitrogen atoms number between the monomers. It is worthy of note that an interesting interlayer charge transfer character is induced in the polar hetero-dimers, which is dependent on the difference between the electronegativity of the monomers. It is our expectation that the new knowledge about the bonding nature of radical hetero-dimers might provide important information for designing radical based functional materials with various applications.

  7. Serological Detection of Borrelia burgdorferi among Horses in Korea

    PubMed Central

    Lee, Seung-Hun; Yun, Sun-Hee; Choi, Eunsang; Park, Yong-Soo; Lee, Sang-Eun; Cho, Gil-Jae; Kwon, Oh-Deog; Kwak, Dongmi

    2016-01-01

    Lyme disease is a tick-borne zoonotic infectious disease caused by Borrelia burgdorferi. The present study assessed the infection status of B. burgdorferi among horses reared in Korea using ELISA and PCR. Between 2009 and 2013, blood samples were collected from 727 horses throughout Korea. Data for each animal including age, gender, breed, and region of sample collection were used for epidemiological analysis. Overall, 38 (5.2%; true prevalence: 5.5%) of 727 horses were seropositive by ELISA. There were statistically significant differences according to breed and region (P<0.001) whose differences might be attributed to the ecology of vector ticks and climate conditions. Using 2 nested PCR, none of the samples tested positive for B. burgdorferi. Thus, a positive ELISA result can indicate only that the tested horse was previously exposed to B. burgdorferi, with no certainty over the time of exposure. Since global warming is likely to increase the abundance of ticks in Korea, continuous monitoring of tick-borne diseases in Korean horses is needed. PMID:26951987

  8. Pleomorphic forms of Borrelia burgdorferi induce distinct immune responses.

    PubMed

    Meriläinen, Leena; Brander, Heini; Herranen, Anni; Schwarzbach, Armin; Gilbert, Leona

    2016-01-01

    Borrelia burgdorferi is the causative agent of tick-borne Lyme disease. As a response to environmental stress B. burgdorferi can change its morphology to a round body form. The role of B. burgdorferi pleomorphic forms in Lyme disease pathogenesis has long been debated and unclear. Here, we demonstrated that round bodies were processed differently in differentiated macrophages, consequently inducing distinct immune responses compared to spirochetes in vitro. Colocalization analysis indicated that the F-actin participates in internalization of both forms. However, round bodies end up less in macrophage lysosomes than spirochetes suggesting that there are differences in processing of these forms in phagocytic cells. Furthermore, round bodies stimulated distinct cytokine and chemokine production in these cells. We confirmed that spirochetes and round bodies present different protein profiles and antigenicity. In a Western blot analysis Lyme disease patients had more intense responses to round bodies when compared to spirochetes. These results suggest that round bodies have a role in Lyme disease pathogenesis. PMID:27139815

  9. The Elastic Basis for the Shape of Borrelia burgdorferi

    PubMed Central

    Dombrowski, Christopher; Kan, Wanxi; Motaleb, Md. Abdul; Charon, Nyles W.; Goldstein, Raymond E.; Wolgemuth, Charles W.

    2009-01-01

    The mechanisms that determine bacterial shape are in many ways poorly understood. A prime example is the Lyme disease spirochete, Borrelia burgdorferi (B. burgdorferi), which mechanically couples its motility organelles, helical flagella, to its rod-shaped cell body, producing a striking flat-wave morphology. A mathematical model is developed here that accounts for the elastic coupling of the flagella to the cell cylinder and shows that the flat-wave morphology is in fact a natural consequence of the geometrical and material properties of the components. Observations of purified periplasmic flagella show two flagellar conformations. The mathematical model suggests that the larger waveform flagellum is the more relevant for determining the shape of B. burgdorferi. Optical trapping experiments were used to measure directly the mechanical properties of these spirochetes. These results imply relative stiffnesses of the two components, which confirm the predictions of the model and show that the morphology of B. burgdorferi is completely determined by the elastic properties of the flagella and cell body. This approach is applicable to a variety of other structures in which the shape of the composite system is markedly different from that of the individual components, such as coiled-coil domains in proteins and the eukaryotic axoneme. PMID:19486665

  10. Membrane topology of Borrelia burgdorferi and Treponema pallidum lipoproteins.

    PubMed Central

    Jones, J D; Bourell, K W; Norgard, M V; Radolf, J D

    1995-01-01

    A critical issue regarding the molecular architectures of Treponema pallidum and Borrelia burgdorferi, the agents of venereal syphilis and Lyme disease, respectively, concerns the membrane topologies of their major lipoprotein immunogens. A related question is whether these lipid-modified membrane proteins form intramembranous particles during freeze fracture electron microscopy. To address these issues, native borrelial and treponemal lipoproteins were reconstituted into liposomes of diverse composition. The importance of the covalently associated lipids for membrane association of lipoproteins was revealed by the observation that nonlipidated recombinant forms of both B. burgdorferi OspA and the T. pallidum 47-kDa immunogen (Tpp47) showed very weak or no binding to model bilayer vesicles. In contrast to control liposomes reconstituted with bacteriorhodopsin or bovine rhodopsin, two well-characterized transmembrane proteins, none of the lipoprotein-liposomes contained particles when examined by freeze fracture electron microscopy. To extend these findings to prokaryotic lipoproteins with relatively amphiphilic polypeptides, similar experiments were conducted with a recombinant nonlipidated form of Escherichia coli TraT, a lipoprotein which has putative transmembrane domains. The nonlipidated TraT oligomers bound vesicles derived from E. coli lipids but, surprisingly, did not form particles in the freeze-fractured liposomes. These findings support (i) a proposed topology of spirochetal lipoproteins in which the polypeptide is extrinsic to the membrane surface and (ii) the contention that particles visualized in freeze-fractured spirochetal membranes represent poorly characterized transmembrane proteins. PMID:7790053

  11. aadA Confers Streptomycin Resistance in Borrelia burgdorferi

    PubMed Central

    Frank, Kristi L.; Bundle, Sharyl F.; Kresge, Michele E.; Eggers, Christian H.; Samuels, D. Scott

    2003-01-01

    To enhance genetic manipulation of the Lyme disease spirochete Borrelia burgdorferi, we assayed the aadA gene for the ability to confer resistance to the antibiotics spectinomycin and streptomycin. Using the previously described pBSV2 as a backbone, a shuttle vector, termed pKFSS1, which carries the aadA open reading frame fused to the B. burgdorferi flgB promoter was constructed. The hybrid flgB promoter-aadA cassette confers resistance to spectinomycin and streptomycin in both B. burgdorferi and Escherichia coli. pKFSS1 has a replication origin derived from the 9-kb circular plasmid and can be comaintained in B. burgdorferi with extant shuttle vector pCE320, which has a replication origin derived from a 32-kb circular plasmid, or pBSV2, despite the fact that pKFSS1 and pBSV2 have the same replication origin. Our results demonstrate the availability of a new selectable marker and shuttle vector for genetically dissecting B. burgdorferi at the molecular level. PMID:14594849

  12. Immunogenic integral membrane proteins of Borrelia burgdorferi are lipoproteins.

    PubMed

    Brandt, M E; Riley, B S; Radolf, J D; Norgard, M V

    1990-04-01

    The pathogenic spirochete Borrelia burgdorferi contains a set of integral membrane proteins which were selectively extracted into the detergent phase upon solubilization of intact B. burgdorferi with the nonionic detergent Triton X-114. Virtually all of these hydrophobic proteins were recognized by antibodies in pooled sera from patients with chronic Lyme arthritis, demonstrating that proteins partitioning into the detergent phase of Triton X-114 encompass the major B. burgdorferi immunogens. Furthermore, most of these immunogenic proteins, including the previously characterized OspA and OspB membrane antigens, could be biosynthetically labeled when B. burgdorferi was incubated in vitro with [3H]palmitate. The OspA and OspB antigens were radioimmunoprecipitated from [3H]palmitate-labeled detergent-phase proteins with monoclonal antibodies, and [3H]palmitate was recovered unaltered from these proteins after sequential alkaline and acid hydrolyses. The combined results provide formal confirmation that the major B. burgdorferi immunogens extracted by Triton X-114 are lipoproteins. The demonstration that B. burgdorferi integral membrane antigens are lipoproteins may explain the basis of their immunogenicity and may help to improve our understanding of the surface topology of B. burgdorferi. PMID:2318538

  13. Linear and Circular Plasmid Content in Borrelia burgdorferi Clinical Isolates

    PubMed Central

    Iyer, Radha; Kalu, Ogori; Purser, Joye; Norris, Steven; Stevenson, Brian; Schwartz, Ira

    2003-01-01

    The genome of Borrelia burgdorferi, the etiologic agent of Lyme disease, is composed of a linear chromosome and more than 20 linear and circular plasmids. Typically, plasmid content analysis has been carried out by pulsed-field gel electrophoresis and confirmed by Southern hybridization. However, multiple plasmids of virtually identical sizes (e.g., lp28 and cp32) complicate the interpretation of such data. The present study was undertaken to investigate the complete plasmid complements of B. burgdorferi clinical isolates cultivated from patients from a single region where early Lyme disease is endemic. A total of 21 isolates obtained from the skin biopsy or blood samples of Lyme disease patients were examined for their complete plasmid complements by Southern hybridization and plasmid-specific PCR analysis. All clinical isolates harbored at least six of the nine previously characterized cp32s. Fourteen isolates harbored all B31-like linear plasmids, and seven isolates simultaneously lacked lp56, lp38, and some segments of lp28-1. The distinctive plasmid profile observed in these seven isolates was specific to organisms that had ribosomal spacer type 2 and pulsed-field gel type A, which implies a clonal origin for this genotype. The presence of nearly identical complements of multiple linear and circular plasmids in all of the human isolates suggests that these plasmids may be particularly necessary for infection, adaptation, and/or maintenance in the infected host. PMID:12819050

  14. Serological Detection of Borrelia burgdorferi among Horses in Korea.

    PubMed

    Lee, Seung-Hun; Yun, Sun-Hee; Choi, Eunsang; Park, Yong-Soo; Lee, Sang-Eun; Cho, Gil-Jae; Kwon, Oh-Deog; Kwak, Dongmi

    2016-02-01

    Lyme disease is a tick-borne zoonotic infectious disease caused by Borrelia burgdorferi. The present study assessed the infection status of B. burgdorferi among horses reared in Korea using ELISA and PCR. Between 2009 and 2013, blood samples were collected from 727 horses throughout Korea. Data for each animal including age, gender, breed, and region of sample collection were used for epidemiological analysis. Overall, 38 (5.2%; true prevalence: 5.5%) of 727 horses were seropositive by ELISA. There were statistically significant differences according to breed and region (P<0.001) whose differences might be attributed to the ecology of vector ticks and climate conditions. Using 2 nested PCR, none of the samples tested positive for B. burgdorferi. Thus, a positive ELISA result can indicate only that the tested horse was previously exposed to B. burgdorferi, with no certainty over the time of exposure. Since global warming is likely to increase the abundance of ticks in Korea, continuous monitoring of tick-borne diseases in Korean horses is needed. PMID:26951987

  15. PCR in laboratory diagnosis of human Borrelia burgdorferi infections.

    PubMed Central

    Schmidt, B L

    1997-01-01

    The laboratory diagnosis of Lyme borreliosis, the most prevalent vector-borne disease in the United States and endemic in parts of Europe and Asia, is currently based on serology with known limitations. Direct demonstration of Borrelia burgdorferi by culture may require weeks, while enzyme-linked immunosorbent assays for antigen detection often lack sensitivity. The development of the PCR has offered a new dimension in the diagnosis. Capable of amplifying minute amounts of DNA into billions of copies in just a few hours, PCR facilitates the sensitive and specific detection of DNA or RNA of pathogenic organisms. This review is restricted to applications of PCR methods in the diagnosis of human B. burgdorferi infections. In the first section, methodological aspects, e.g., sample preparation, target selection, primers and PCR methods, and detection and control of inhibition and contamination, are highlighted. In the second part, emphasis is placed on diagnostic aspects, where PCR results in patients with dermatological, neurological, joint, and ocular manifestations of the disease are discussed. Here, special attention is given to monitoring treatment efficacy by PCR tests. Last, specific guidelines on how to interpret PCR results, together with the advantages and limitations of these new techniques, are presented. PMID:8993863

  16. Distribution of Borrelia burgdorferi in host mice in Pennsylvania.

    PubMed Central

    Lord, R D; Lord, V R; Humphreys, J G; McLean, R G

    1994-01-01

    Host mice (Peromyscus leucopus and Peromyscus maniculatus) were sampled throughout the state of Pennsylvania to determine the geographical and ecological distribution of the Lyme disease spirochete Borrelia burgdorferi. All 67 counties of the state were sampled. A total of 1,619 mice were captured from a total of 157 sites during the period 1990 to 1993 for an overall capture rate of 29.69%. A total of 112 (6.92%) isolations of B. burgdorferi were made. The distribution of isolations revealed the reason for the correlated distribution of human cases of Lyme disease in the state. Significantly more mice were captured and significantly more isolations were made from hemlock (Tsuga canadensis) habitat than from deciduous species forest. Nevertheless, high isolation rates from counties of the southeastern corner of the state illustrate well that hemlock habitat is not essential. Evidence suggests that in some areas, transmission between mice is occurring in some way other than through ticks as vectors. Host mice proved useful for determining the geographical and ecological distribution of B. burgdorferi. PMID:7814489

  17. Virulent strain associated outer membrane proteins of Borrelia burgdorferi.

    PubMed Central

    Skare, J T; Shang, E S; Foley, D M; Blanco, D R; Champion, C I; Mirzabekov, T; Sokolov, Y; Kagan, B L; Miller, J N; Lovett, M A

    1995-01-01

    We have isolated and purified outer membrane vesicles (OMV) from Borrelia burgdorferi strain B31 based on methods developed for isolation of Treponema pallidum OMV. Purified OMV exhibited distinct porin activities with conductances of 0.6 and 12.6 nano-Siemen and had no detectable beta-NADH oxidase activity indicating their outer membrane origin and their lack of inner membrane contamination, respectively. Hydrophobic proteins were identified by phase partitioning with Triton X-114. Most of these hydrophobic membrane proteins were not acylated, suggesting that they are outer membrane-spanning proteins. Identification of palmitate-labeled lipoproteins revealed that several were enriched in the OMV, several were enriched in the protoplasmic cylinder inner membrane fraction, and others were found exclusively associated with the inner membrane. The protein composition of OMV changed significantly with successive in vitro cultivation of strain B31. Using antiserum with specificity for virulent strain B31, we identified OMV antigens on the surface of the spirochete and identified proteins whose presence in OMV could be correlated with virulence and protective immunity in the rabbit Lyme disease model. These virulent strain associated outer membrane-spanning proteins may provide new insight into the pathogenesis of Lyme disease. Images PMID:7593626

  18. Morphological and biochemical features of Borrelia burgdorferi pleomorphic forms

    PubMed Central

    Herranen, Anni; Schwarzbach, Armin; Gilbert, Leona

    2015-01-01

    The spirochaete bacterium Borrelia burgdorferi sensu lato is the causative agent of Lyme disease, the most common tick-borne infection in the northern hemisphere. There is a long-standing debate regarding the role of pleomorphic forms in Lyme disease pathogenesis, while very little is known about the characteristics of these morphological variants. Here, we present a comprehensive analysis of B. burgdorferi pleomorphic formation in different culturing conditions at physiological temperature. Interestingly, human serum induced the bacterium to change its morphology to round bodies (RBs). In addition, biofilm-like colonies in suspension were found to be part of B. burgdorferi’s normal in vitro growth. Further studies provided evidence that spherical RBs had an intact and flexible cell envelope, demonstrating that they are not cell wall deficient, or degenerative as previously implied. However, the RBs displayed lower metabolic activity compared with spirochaetes. Furthermore, our results indicated that the different pleomorphic variants were distinguishable by having unique biochemical signatures. Consequently, pleomorphic B. burgdorferi should be taken into consideration as being clinically relevant and influence the development of novel diagnostics and treatment protocols. PMID:25564498

  19. Subunit isoform selectivity in assembly of Na,K-ATPase α-β heterodimers.

    PubMed

    Tokhtaeva, Elmira; Clifford, Rebecca J; Kaplan, Jack H; Sachs, George; Vagin, Olga

    2012-07-27

    To catalyze ion transport, the Na,K-ATPase must contain one α and one β subunit. When expressed by transfection in various expression systems, each of the four α subunit isoforms can assemble with each of the three β subunit isoforms and form an active enzyme, suggesting the absence of selective α-β isoform assembly. However, it is unknown whether in vivo conditions the α-β assembly is random or isoform-specific. The α(2)-β(2) complex was selectively immunoprecipitated by both anti-α(2) and anti-β(2) antibodies from extracts of mouse brain, which contains cells co-expressing multiple Na,K-ATPase isoforms. Neither α(1)-β(2) nor α(2)-β(1) complexes were detected in the immunoprecipitates. Furthermore, in MDCK cells co-expressing α(1), β(1), and β(2) isoforms, a greater fraction of the β(2) subunits was unassembled with α(1) as compared with that of the β(1) subunits, indicating preferential association of the α(1) isoform with the β(1) isoform. In addition, the α(1)-β(2) complex was less resistant to various detergents than the α(1)-β(1) complex isolated from MDCK cells or the α(2)-β(2) complex isolated from mouse brain. Therefore, the diversity of the α-β Na,K-ATPase heterodimers in vivo is determined not only by cell-specific co-expression of particular isoforms, but also by selective association of the α and β subunit isoforms. PMID:22696220

  20. Small heterodimer partner overexpression partially protects against liver tumor development in farnesoid X receptor knockout mice

    SciTech Connect

    Li, Guodong; Kong, Bo; Zhu, Yan; Zhan, Le; Williams, Jessica A.; Tawfik, Ossama; Kassel, Karen M.; Luyendyk, James P.; Wang, Li; Guo, Grace L.

    2013-10-15

    Farnesoid X receptor (FXR, Nr1h4) and small heterodimer partner (SHP, Nr0b2) are nuclear receptors that are critical to liver homeostasis. Induction of SHP serves as a major mechanism of FXR in suppressing gene expression. Both FXR{sup −/−} and SHP{sup −/−} mice develop spontaneous hepatocellular carcinoma (HCC). SHP is one of the most strongly induced genes by FXR in the liver and is a tumor suppressor, therefore, we hypothesized that deficiency of SHP contributes to HCC development in the livers of FXR{sup −/−} mice and therefore, increased SHP expression in FXR{sup −/−} mice reduces liver tumorigenesis. To test this hypothesis, we generated FXR{sup −/−} mice with overexpression of SHP in hepatocytes (FXR{sup −/−}/SHP{sup Tg}) and determined the contribution of SHP in HCC development in FXR{sup −/−} mice. Hepatocyte-specific SHP overexpression did not affect liver tumor incidence or size in FXR{sup −/−} mice. However, SHP overexpression led to a lower grade of dysplasia, reduced indicator cell proliferation and increased apoptosis. All tumor-bearing mice had increased serum bile acid levels and IL-6 levels, which was associated with activation of hepatic STAT3. In conclusion, SHP partially protects FXR{sup −/−} mice from HCC formation by reducing tumor malignancy. However, disrupted bile acid homeostasis by FXR deficiency leads to inflammation and injury, which ultimately results in uncontrolled cell proliferation and tumorigenesis in the liver. - Highlights: • SHP does not prevent HCC incidence nor size in FXR KO mice but reduces malignancy. • Increased SHP promotes apoptosis. • Bile acids and inflammation maybe critical for HCC formation with FXR deficiency.

  1. Human cyclooxygenase-2 is a sequence homodimer that functions as a conformational heterodimer.

    PubMed

    Dong, Liang; Vecchio, Alex J; Sharma, Narayan P; Jurban, Brice J; Malkowski, Michael G; Smith, William L

    2011-05-27

    Prostaglandin endoperoxide H synthases 1 and 2, also known as cyclooxygenases (COXs) 1 and 2, convert arachidonic acid (AA) to prostaglandin endoperoxide H(2). Prostaglandin endoperoxide H synthases are targets of nonspecific nonsteroidal anti-inflammatory drugs and COX-2-specific inhibitors called coxibs. PGHS-2 is a sequence homodimer. Each monomer has a peroxidase and a COX active site. We find that human PGHS-2 functions as a conformational heterodimer having a catalytic monomer (E(cat)) and an allosteric monomer (E(allo)). Heme binds tightly only to the peroxidase site of E(cat), whereas substrates, as well as certain inhibitors (e.g. celecoxib), bind the COX site of E(cat). E(cat) is regulated by E(allo) in a manner dependent on what ligand is bound to E(allo). Substrate and nonsubstrate fatty acids (FAs) and some COX inhibitors (e.g. naproxen) preferentially bind to the COX site of E(allo). AA can bind to E(cat) and E(allo), but the affinity of AA for E(allo) is 25 times that for E(cat). Palmitic acid, an efficacious stimulator of human PGHS-2, binds only E(allo) in palmitic acid/murine PGHS-2 co-crystals. Nonsubstrate FAs can potentiate or attenuate actions of COX inhibitors depending on the FA and whether the inhibitor binds E(cat) or E(allo). Our studies suggest that the concentration and composition of the free FA pool in the environment in which PGHS-2 functions in cells, the FA tone, is a key factor regulating PGHS-2 activity and its responses to COX inhibitors. We suggest that differences in FA tone occurring with different diets will likely affect both base-line prostanoid synthesis and responses to COX inhibitors. PMID:21467029

  2. [Borrelia burgdorferi sensu lato in ixodid ticks from Ostrava slag heaps].

    PubMed

    Jarosová, V; Rudolf, I; Halouzka, J; Hubálek, Z

    2009-04-01

    In 2005 and 2006, Ixodes ricinus ticks were collected on two slag (waste rock) heaps from coal mines in the Ostrava area (North Moravia/Silesia, Czech Republic), Oskar (site A) and Emma (site B), partially covered by vegetation including trees, and at a control forest site near Hlucín (site C). The mean numbers of L. ricinus nymphs and imagoes flagged per person-hour were high: 35.3 nymphs and 12.7 imagoes, at site A, 23.3 and 26.0, respectively, at site B, and 25.4 and 16.8, respectively, at control site C. Using dark-field microscopy, 100 nymphs and 100 imagoes (50 females and 50 males) from each site were examined for borreliae. The mean prevalence rates of Borrelia burgdorferi sensu lato in nymphs and imagoes were 10.0% and 12.0%, respectively, at site A, 10.0% and 24.0%, respectively, at site B, and 13.0% and 17.0%, respectively, at site C. Differences in the prevalence of borreliae in nymphal and adult ticks from the slag heaps and control site were insignificant, but adult ticks from site B compared to site A contained borreliae significantly more frequently. The mean numbers of nymphs and imagoes infected with borreliae flagged per person-hour were 3.3 and 1.2, respectively at site A, 1.5 and 2.9, respectively, at site B, and 3.1 and 2.6, respectively, at site C. Isolation experiments for borreliae were carried out only in 16 ticks containing higher numbers of borreliae, with eight of these being culture-positive. The cultured borreliae were identified by PCR-RFLP as B. garinii (3 isolates: two from site B, one from site C), B. afzelii (4 isolates: one from site A, three from site B) and B. burgdorferi s.s. (one isolate from site A). Surprisingly, the results suggest that slag heaps, when covered by woody vegetation and frequented by humans, could theoretically pose roughly the same LB transmission risk to humans as common forest biotopes. PMID:19526923

  3. Vascular Endothelial Growth Factor/Placental Growth Factor Heterodimer Levels in Preterm Infants with Bronchopulmonary Dysplasia.

    PubMed

    Procianoy, Renato S; Hentges, Cláudia R; Silveira, Rita C

    2016-04-01

    Background Bronchopulmonary dysplasia (BPD) is associated with changes in pulmonary angiogenesis. However, the role of the vascular endothelial growth factor/placental growth factor (VEGF/PlGF) heterodimer, an antiangiogenic factor, remains unknown in this disease. Objective To compare VEGF/PlGF levels in preterm infants with and without BPD. Methods This study was approved by the Institutional Review Board. Preterm neonates with birth weight <2,000 g and gestational age ≤34 weeks were included. Exclusion criteria were: neonates transferred from other institutions after 72 hours of life; death before blood collection; presence of major congenital malformations, inborn errors of metabolism, and early sepsis; and mothers with multiple pregnancies, TORCH infections, HIV infection, or autoimmune diseases. BPD was defined as the need for oxygen therapy for a period equal to or greater than 28 days, accompanied by radiographic changes compatible with the disease. Blood was collected from neonates in the first 72 hours of life. VEGF/PlGF levels were measured using the enzyme-linked immunosorbent assay method. The chi-square test, t-test, Mann-Whitney test, analysis of variance, and Kruskal-Wallis test were used for statistical analysis. Variables found to be significant in the univariate analysis were included in the multivariate analysis. Results Seventy-three patients were included (19 with BPD, 43 without BPD, and 11 neonates who died in the first 28 days of life), with a mean (SD) gestational age of 30.32 (2.88) weeks and birth weight of 1,288 (462) g. Median VEGF/PlGF levels were higher in the groups with BPD and death in the first 28 days of life than in the group without BPD (16.46 [IQR, 12.19-44.57] and 20.64 [IQR, 13.39-50.22], respectively, vs. 9.14 [IQR, 0.02-20.64] pg/mL], p < 0.001). Higher VEGF/P1GF levels remained associated with BPD and death in the first 28 days of life in the multivariate analysis. Conclusion Higher plasma VEGF

  4. Atomic Simulation of Complex DNA DSBs and the Interactions with the Ku70/80 Heterodimer

    NASA Technical Reports Server (NTRS)

    Hu, Shaowen; Cucinotta, Francis A.

    2011-01-01

    DNA double strand breaks (DSBs) induced by ionizing radiation (IR) usually contain modified bases such as 8-oxo-7,8-dihydroguanine (8-oxoG) and thymine glycol, apurinic/apyrimidinic (AP) sites, 2-deoxyribonolactone, or single-strand breaks (SSBs). The presence of such lesions in close proximity to the DSB terminus makes the DNA nicks more difficult to repair and rejoin than endogenously induced simple DSBs, and as such a major determinant of the biological effects of high linear energy transfer (LET) radiation as encountered in space travel. In this study we conducted molecular dynamics simulations on a series of DNA duplexes with various complex lesions of 8-oxoG and AP sites, in an effort to investigate the effects of such lesions to the structural integrity and stability of DNA after insulted by IR. We also simulated the interaction of such complex DSBs with the Ku70/80 heterodimer, the first protein in mammalian cells to embark the non-homologous end joining (NHEJ) DNA repair pathway. The results indicate, compared to DNA with simple DSBs, the complex lesions can enhance the hydrogen bonds opening rate at the DNA terminus, and increase the mobility of the whole duplex, thus they present more deleterious effects to the genome integrity if not captured and repaired promptly in cells. Simulations also demonstrate the binding of Ku drastically reduces structural disruption and flexibility caused by the complex lesions, and the interactions of Ku with complex DSBs have a different potential energy landscape from the bound structure with simple DSB. In all complex DSBs systems, the binding of DSB terminus with Ku70 is softened while the binding of the middle duplex with Ku80 is tightened. This energy shift may help the Ku protein to secure at the DSB terminus for a longer time, so that other end processing factors or repair pathways can proceed at the lesions before NHEJ repair process starts. These atomic simulations may provide valuable new insight into the

  5. Borrelia hermsii Acquisition Order in Superinfected Ticks Determines Transmission Efficiency

    PubMed Central

    Raffel, Sandra J.; Schwan, Tom G.

    2013-01-01

    Multilocus sequence typing of Borrelia hermsii isolates reveals its divergence into two major genomic groups (GG), but no differences in transmission efficiency or host pathogenicity are associated with these genotypes. To compare GGI and GGII in the tick-host infection cycle, we first determined if spirochetes from the two groups could superinfect the tick vector Ornithodoros hermsi. We infected mice with isolates from each group and fed ticks sequentially on these mice. We then fed the infected ticks on naive mice and measured GGI and GGII spirochete densities in vector and host, using quantitative PCR of genotype-specific chromosomal DNA sequences. Sequential feedings resulted in dual tick infections, showing that GGI or GGII primary acquisition did not block superinfection by a secondary agent. On transmission to naive mice at short intervals after acquisition, ticks with primary GGI and secondary GGII spirochete infections caused mixed GGI and GGII infections in mice. However, ticks with primary GGII and secondary GGI spirochete infections caused only GGII infections with all isolate pairs examined. At longer intervals after acquisition, the exclusion of GGI by GGII spirochetes declined and cotransmission predominated. We then examined GGI and GGII spirochetemia in mice following single inoculation and coinoculation by needle and found that GGI spirochete densities were reduced on multiple days when coinoculated with GGII. These findings indicate that dual GGI-GGII spirochete infections can persist in ticks and that transmission to a vertebrate host is dependent on the order of tick acquisition and the interval between acquisition and transmission events. PMID:23716615

  6. Patterns and regulation of ribosomal RNA transcription in Borrelia burgdorferi

    PubMed Central

    2011-01-01

    Background Borrelia burgdorferi contains one 16S and two tandem sets of 23S-5S ribosomal (r) RNA genes whose patterns of transcription and regulation are unknown but are likely to be critical for survival and persistence in its hosts. Results RT-PCR of B. burgdorferi N40 and B31 revealed three rRNA region transcripts: 16S rRNA-alanine transfer RNA (tRNAAla); tRNAIle; and both sets of 23S-5S rRNA. At 34°C, there were no differences in growth rate or in accumulation of total protein, DNA and RNA in B31 cultured in Barbour-Stoenner-Kelly (BSK)-H whether rabbit serum was present or not. At 23°C, B31 grew more slowly in serum-containing BSK-H than at 34°C. DNA per cell was higher in cells in exponential as compared to stationary phase at either temperature; protein per cell was similar at both temperatures in both phases. Similar amounts of rRNA were produced in exponential phase at both temperatures, and rRNA was down-regulated in stationary phase at either temperature. Interestingly, a relBbu deletion mutant unable to generate (p)ppGpp did not down-regulate rRNA at transition to stationary phase in serum-containing BSK-H at 34°C, similar to the relaxed phenotype of E. coli relA mutants. Conclusions We conclude that rRNA transcription in B. burgdorferi is complex and regulated both by growth phase and by the stringent response but not by temperature-modulated growth rate. PMID:21251259

  7. Fatty acids of Treponema pallidum and Borrelia burgdorferi lipoproteins.

    PubMed Central

    Belisle, J T; Brandt, M E; Radolf, J D; Norgard, M V

    1994-01-01

    A fundamental ultrastructural feature shared by the spirochetal pathogens Treponema pallidum subsp. pallidum (T. pallidum) and Borrelia burgdorferi, the etiological agents of venereal syphilis and Lyme disease, respectively, is that their most abundant membrane proteins contain covalently attached fatty acids. In this study, we identified the fatty acids covalently bound to lipoproteins of B. burgdorferi and T. pallidum and examined potential acyl donors to these molecules. Palmitate was the predominant fatty acid of both B. burgdorferi and T. pallidum lipoproteins. T. pallidum lipoproteins also contained substantial amounts of stearate, a fatty acid not typically prevalent in prokaryotic lipoproteins. In both spirochetes, the fatty acids of cellular lipids differed from those of their respective lipoproteins. To characterize phospholipids in these organisms, spirochetes were metabolically labeled with [3H]palmitate or [3H]oleate; B. burgdorferi contained only phosphatidylglycerol and phosphatidylcholine, while T. pallidum contained phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, and cardiolipin. Although palmitate predominated in the lipoproteins, there were no apparent differences in the incorporation of these two fatty acids into phospholipids (putative acyl donors). Phospholipase A1 and A2 digestion of phosphatidylcholine from B. burgdorferi and T. pallidum labeled with either [3H]palmitate or [3H]oleate also revealed that neither fatty acid was incorporated preferentially into the 1 and 2 positions (potential acyl donor sites) of the glycerol backbone. The combined findings suggest that fatty acid utilization during lipoprotein synthesis is determined largely by the fatty acid specificities of the lipoprotein acyl transferases. These findings also provide the basis for ongoing efforts to elucidate the relationship between lipoprotein acylation and the physiological functions and inflammatory

  8. Babesia microti, human babesiosis, and Borrelia burgdorferi in Connecticut.

    PubMed Central

    Anderson, J F; Mintz, E D; Gadbaw, J J; Magnarelli, L A

    1991-01-01

    Babesia microti was isolated from a white-footed mouse (Peromyscus leucopus) that was captured in southeastern Connecticut in 1988, when the first human case of babesiosis acquired in Connecticut was recognized. To date, 13 cases of babesiosis have been reported in Connecticut, the largest number of human cases reported on the mainland United States. Two of nine patients quiried remembered a prior tick bite. Since Babesia parasites are known to be vectored only by ticks, we surmise that 12 of these infections were acquired via tick bites; 1 was obtained by blood transfusion (the patient was 46 years of age) from an endemically infected donor. The ages of the patients with tick-acquired babesiosis ranged from 61 to 95 years. Two patients died with active infections, and one patient died from chronic obstructive pulmonary disease soon after treatment with clindamycin and quinine. Indirect fluorescent-antibody titers of blood samples drawn at the time of hospitalization for 11 patients and at the time of active infection for 1 asymptomatic person ranged from 1:1,024 to 1:4,096. Five of eight patients with babesiosis also had significant immunoglobulin G or immunoglobulin M titers (1:640 to 1:5,120) to Borrelia burgdorferi. B. microti was isolated in Syrian hamsters inoculated with blood from 7 of 12 patients tested and was also isolated from mice captured in six towns. The peridomestic nature of the disease was demonstrated by isolating the parasite from white-footed mice captured in or near the yards of eight different patients. Of 59 mice tested, 27 were positive and 25 were coinfected with B. burgdorferi. The isolation of B. microti from a white-footed mouse captured in north-central Connecticut (West Hartford), away from the focus of human infections in southeastern Connecticut, suggests that this pathogen may spread into other areas where Ixodes dammini, the tick vector, becomes established. PMID:1757548

  9. Two Boundaries Separate Borrelia burgdorferi Populations in North America

    PubMed Central

    Tsao, Jean I.; Castillo-Ramírez, Santiago; Girard, Yvette A.; Hamer, Sarah A.; Hoen, Anne Gatewood; Lane, Robert S.; Raper, Steve L.; Ogden, Nicholas H.

    2012-01-01

    Understanding the spread of infectious diseases is crucial for implementing effective control measures. For this, it is important to obtain information on the contemporary population structure of a disease agent and to infer the evolutionary processes that may have shaped it. Here, we investigate on a continental scale the population structure of Borrelia burgdorferi, the causative agent of Lyme borreliosis (LB), a tick-borne disease, in North America. We test the hypothesis that the observed population structure is congruent with recent population expansions and that these were preceded by bottlenecks mostly likely caused by the near extirpation in the 1900s of hosts required for sustaining tick populations. Multilocus sequence typing and complementary population analytical tools were used to evaluate B. burgdorferi samples collected in the Northeastern, Upper Midwestern, and Far-Western United States and Canada. The spatial distribution of sequence types (STs) and inferred population boundaries suggest that the current populations are geographically separated. One major population boundary separated western B. burgdorferi populations transmitted by Ixodes pacificus in California from Eastern populations transmitted by I. scapularis; the other divided Midwestern and Northeastern populations. However, populations from all three regions were genetically closely related. Together, our findings suggest that although the contemporary populations of North American B. burgdorferi now comprise three geographically separated subpopulations with no or limited gene flow among them, they arose from a common ancestral population. A comparative analysis of the B. burgdorferi outer surface protein C (ospC) gene revealed novel linkages and provides additional insights into the genetic characteristics of strains. PMID:22729536

  10. Differential Expression of Borrelia burgdorferi Proteins during Growth In Vitro

    PubMed Central

    Ramamoorthy, Ramesh; Philipp, Mario T.

    1998-01-01

    In an earlier paper we described the transcriptionally regulated differential levels of expression of two lipoproteins of Borrelia burgdorferi, P35 and P7.5, during growth of the spirochetes in culture from logarithmic phase to stationary phase (K. J. Indest, R. Ramamoorthy, M. Solé, R. D. Gilmore, B. J. B. Johnson, and M. T. Philipp, Infect. Immun. 65:1165–1171, 1997). Here we further assess this phenomenon by investigating whether the expression of other antigens of B. burgdorferi, including some well-characterized ones, are also regulated in a growth-phase-dependent manner in vitro. These studies revealed 13 additional antigens, including OspC, BmpD, and GroEL, that were upregulated 2- to 66-fold and a 28-kDa protein that was downregulated 2- to 10-fold, during the interval between the logarithmic- and stationary-growth phases. Unlike with these in vitro-regulated proteins, the levels of expression of OspA, OspB, P72, flagellin, and BmpA remained unchanged throughout growth of the spirochetes in culture. Furthermore, ospAB, bmpAB, groEL, and fla all exhibited similar mRNA profiles, which is consistent with the constitutive expression of these genes. By contrast, the mRNA and protein profiles of ospC and bmpD indicated regulated expression of these genes. While bmpD exhibited a spike in mRNA expression in early stationary phase, ospC maintained a relatively higher level of mRNA throughout culture. These findings demonstrate that there are additional genes besides P7.5 and P35 whose regulated expression can be investigated in vitro and which may thus serve as models to facilitate the study of regulatory mechanisms in an organism that cycles between an arthropod and a vertebrate host. PMID:9784512

  11. A relapsing fever group Borrelia sp. similar to Borrelia lonestari found among wild sika deer (Cervus nippon yesoensis) and Haemaphysalis spp. ticks in Hokkaido, Japan.

    PubMed

    Lee, Kyunglee; Takano, Ai; Taylor, Kyle; Sashika, Mariko; Shimozuru, Michito; Konnai, Satoru; Kawabata, Hiroki; Tsubota, Toshio

    2014-10-01

    A relapsing fever Borrelia sp. similar to Borrelia lonestari (herein referred to as B. lonestari-like) was detected from wild sika deer (Cervus nippon yesoensis) and Haemaphysalis ticks in the eastern part of Hokkaido, Japan. The total prevalence of this Borrelia sp. in tested deer blood samples was 10.6% using conventional PCR and real-time PCR. The prevalence was significantly higher in deer fawns compared to adults (21.9% and 9.4%, respectively). Additionally, there was significant regional difference between our two sampling areas, Shiretoko and Shibetsu with 17% and 2.8% prevalence, respectively. Regional differences were also found in tick species collected from field and on deer. In the Shiretoko region, Haemaphysalis spp. were more abundant than Ixodes spp., while in Shibetsu, Ixodes spp. were more abundant. Using real-time PCR analysis, B. lonestari-like was detected from 2 out of 290 adult Haemaphysalis spp. ticks and 4 out of 76 pools of nymphs. This is the first report of a B. lonestari-like organism in Haemaphysalis spp. ticks, and the first phylogenetic analysis of this B. lonestari-like organism in Asia. Based on our results, Haemaphysalis spp. are the most likely candidates to act as a vector for B. lonestari-like; furthermore, regional variation of B. lonestari-like prevalence in sika deer may be dependent on the population distribution of these ticks. PMID:25108784

  12. Assembly of a Functional Beta Interferon Enhanceosome Is Dependent on ATF-2–c-jun Heterodimer Orientation

    PubMed Central

    Falvo, James V.; Parekh, Bhavin S.; Lin, Charles H.; Fraenkel, Ernest; Maniatis, Tom

    2000-01-01

    Heterodimeric transcription factors, including the basic region-leucine zipper (bZIP) protein ATF-2–c-jun, are well-characterized components of an enhanceosome that mediates virus induction of the human beta interferon (IFN-β) gene. Here we report that within the IFN-β enhanceosome the ATF-2–c-jun heterodimer binds in a specific orientation, which is required for assembly of a complex between ATF-2–c-jun and interferon regulatory factor 3 (IRF-3). We demonstrate that correct orientation of the ATF-2–c-jun binding site is required for virus induction of the IFN-β gene and for IRF-3-dependent activation of a composite ATF-2– c-jun–IRF site in the IFN-β promoter. We also show that in vitro the DNA-bound ATF-2–c-jun heterodimer adopts a fixed orientation upon the binding of IRF-3 at an adjacent site in the IFN-β enhancer and that the DNA-binding domain of IRF-3 is sufficient to mediate this effect. In addition, we show that the DNA-binding domain of ATF-2 is necessary and sufficient for selective protein-protein interactions with IRF-3. Strikingly, in vivo chromatin immunoprecipitation experiments with IFN-β reporter constructs reveal that recruitment of IRF-3 to the IFN-β promoter upon virus infection is dependent on the orientation of the ATF-2–c-jun heterodimer binding site. These observations demonstrate functional and physical cooperativity between the bZIP and IRF transcription factor families and illustrate the critical role of heterodimeric transcription factors in formation of the IFN-β enhanceosome. PMID:10848607

  13. Structural Basis for a Munc13–1 Homodimer to Munc13–1/RIM Heterodimer Switch

    PubMed Central

    Lu, Jun; Machius, Mischa; Dulubova, Irina; Dai, Han; Südhof, Thomas C; Tomchick, Diana R

    2006-01-01

    C 2 domains are well characterized as Ca 2+/phospholipid-binding modules, but little is known about how they mediate protein–protein interactions. In neurons, a Munc13–1 C 2A-domain/RIM zinc-finger domain (ZF) heterodimer couples synaptic vesicle priming to presynaptic plasticity. We now show that the Munc13–1 C 2A domain homodimerizes, and that homodimerization competes with Munc13–1/RIM heterodimerization. X-ray diffraction studies guided by nuclear magnetic resonance (NMR) experiments reveal the crystal structures of the Munc13–1 C 2A-domain homodimer and the Munc13–1 C 2A-domain/RIM ZF heterodimer at 1.44 Å and 1.78 Å resolution, respectively. The C 2A domain adopts a β-sandwich structure with a four-stranded concave side that mediates homodimerization, leading to the formation of an eight-stranded β-barrel. In contrast, heterodimerization involves the bottom tip of the C 2A-domain β-sandwich and a C-terminal α-helical extension, which wrap around the RIM ZF domain. Our results describe the structural basis for a Munc13–1 homodimer–Munc13–1/RIM heterodimer switch that may be crucial for vesicle priming and presynaptic plasticity, uncovering at the same time an unexpected versatility of C 2 domains as protein–protein interaction modules, and illustrating the power of combining NMR spectroscopy and X-ray crystallography to study protein complexes. PMID:16732694

  14. Multiple bHLH Proteins form Heterodimers to Mediate CRY2-Dependent Regulation of Flowering-Time in Arabidopsis

    PubMed Central

    Li, Kunwu; Liu, Hongtao; Lin, Chentao

    2013-01-01

    Arabidopsis thaliana cryptochrome 2 (CRY2) mediates light control of flowering time. CIB1 (CRY2-interacting bHLH 1) specifically interacts with CRY2 in response to blue light to activate the transcription of FT (Flowering Locus T). In vitro, CIB1 binds to the canonical E-box (CACGTG, also referred to as G-box) with much higher affinity than its interaction with non-canonical E-box (CANNTG) DNA sequences. However, in vivo, CIB1 binds to the chromatin region of the FT promoter, which only contains the non-canonical E-box sequences. Here, we show that CRY2 also interacts with at least CIB5, in response to blue light, but not in darkness or in response to other wavelengths of light. Our genetic analysis demonstrates that CIB1, CIB2, CIB4, and CIB5 act redundantly to activate the transcription of FT and that they are positive regulators of CRY2 mediated flowering. More importantly, CIB1 and other CIBs proteins form heterodimers, and some of the heterodimers have a higher binding affinity than the CIB homodimers to the non-canonical E-box in the in vitro DNA-binding assays. This result explains why in vitro CIB1 and other CIBs bind to the canonical E-box (G-box) with a higher affinity, whereas they are all associated with the non-canonical E-boxes at the FT promoter in vivo. Consistent with the hypothesis that different CIB proteins play similar roles in the CRY2-midiated blue light signaling, the expression of CIB proteins is regulated specifically by blue light. Our study demonstrates that CIBs function redundantly in regulating CRY2-dependent flowering, and that different CIBs form heterodimers to interact with the non-canonical E-box DNA in vivo. PMID:24130508

  15. Chromosome and Plasmids of the Tick-Borne Relapsing Fever Agent Borrelia hermsii.

    PubMed

    Barbour, Alan G

    2016-01-01

    The zoonotic pathogen Borrelia hermsii bears its multiple paralogous genes for variable antigens on several linear plasmids. Application of combined long-read and short-read next-generation sequencing provided complete sequences for antigen-encoding plasmids as well as other linear and circular plasmids and the linear chromosome of the genome. PMID:27284141

  16. Antibodies against Borrelia burgdorferi sensu lato among Adults, Germany, 2008–2011

    PubMed Central

    Fingerle, Volker; Klier, Christiane; Thamm, Michael; Stark, Klaus

    2015-01-01

    To assess Borrelia burgdorferi sensu lato (the cause of Lyme borreliosis) seropositivity in Germany, we tested serum samples from health survey (2008–2011) participants. Seroprevalence was 5.8% among women and 13.0% among men; infection risk was highest among persons >60 years of age. Public health interventions, including education about risk factors and preventive measures, are needed. PMID:25531140

  17. Antibodies against Borrelia burgdorferi sensu lato among Adults, Germany, 2008-2011.

    PubMed

    Wilking, Hendrik; Fingerle, Volker; Klier, Christiane; Thamm, Michael; Stark, Klaus

    2015-01-01

    To assess Borrelia burgdorferi sensu lato (the cause of Lyme borreliosis) seropositivity in Germany, we tested serum samples from health survey (2008-2011) participants. Seroprevalence was 5.8% among women and 13.0% among men; infection risk was highest among persons >60 years of age. Public health interventions, including education about risk factors and preventive measures, are needed. PMID:25531140

  18. Bird-feeding ticks transstadially transmit Borrelia burgdorferi that infect Syrian hamsters.

    PubMed

    Anderson, J F; Magnarelli, L A; Stafford, K C

    1990-01-01

    Bird-feeding Ixodes dammini ticks were documented for the first time to successfully molt and transstadially pass Borrelia burgdorferi spirochetes that were indistinguishable by sodium dodecyl sulfate-polyacrylamide gel electrophoresis from the type B31 strain. Forty-six of 73 blood-engorged larvae and 50 of 66 fully-fed nymphs, removed from wild-caught birds, successfully molted. Borreliae were isolated from 21 of 78 partially- and fully-fed larvae off birds, including six specimens that molted. Spirochete-positive cultures also were obtained from 35 of 60 partially- and fully-fed nymphs that had fed from birds, including 20 nymphs that molted into adult ticks. Transstadially passed borreliae by bird-feeding larval and nymphal I. dammini were infectious to hamsters, leading us to suggest that these ticks are capable of subsequently transmitting infectious spirochetes to mammals, including humans. An isolated of B. burgdorferi, recovered from a bird-feeding larval Ixodes dentatus, was indistinguishable by sodium dodecyl sulfate-polyacrylamide gel electrophoresis from the B31 strain. This isolate, unlike another from I. dentatus off a cottontail rabbit (Sylvilagus floridanus), had a protein band with a molecular weight of approximately 31,000 that reacted with murine monoclonal antibodies H3TS and H5332 in western blot analysis. Thus, closely related borreliae are present in both I. dentatus and I. dammini. PMID:2304189

  19. The Lyme disease agent Borrelia burgdorferi requires BB0690, a Dps homologue, to persist within ticks.

    PubMed

    Li, Xin; Pal, Utpal; Ramamoorthi, Nandhini; Liu, Xianzhong; Desrosiers, Daniel C; Eggers, Christian H; Anderson, John F; Radolf, Justin D; Fikrig, Erol

    2007-02-01

    Borrelia burgdorferi survives in an enzootic cycle, and Dps proteins protect DNA against damage during starvation or oxidative stress. The role of a Dps homologue encoded by Borrelia in spirochaete survival was assessed. Dps-deficient spirochaetes were infectious in mice via needle-inoculation at the dose of 10(5) spirochaetes. Larval ticks successfully acquired Dps-deficient spirochaetes via a blood meal on mice. However, after extended periods within unfed nymphs, the Dps-deficient spirochaetes failed to be transmitted to a new host when nymphs fed. Our data suggest that Dps functions to protect the spirochaetes during dormancy in unfed ticks, and in its absence, the spirochaetes become susceptible during tick feeding. dps is differentially expressed in vivo- low in mice and high in ticks - but constitutively expressed in vitro, showing little change during growth or in response to oxidative stress. Borrelia Dps forms a dodecameric complex capable of sequestering iron. The Dps-deficient spirochaetes showed no defect in starvation and oxidative stress assays, perhaps due to the lack of iron in spirochaetes grown in vitro. Dps is critical for spirochaete persistence within ticks, and strategies to interfere with Dps could potentially reduce Borrelia populations in nature and thereby influence the incidence of Lyme disease. PMID:17181780

  20. Borrelia miyamotoi Infection in Patients from Upper Midwestern United States, 2014–2015

    PubMed Central

    Jobe, Dean A.; Lovrich, Steven D.; Oldenburg, Darby G.; Kowalski, Todd J.

    2016-01-01

    We confirmed Borrelia miyamotoi infection in 7 patients who had contracted an illness while near La Crosse, Wisconsin, USA, an area where Ixodes scapularis ticks are endemic. B. miyamatoi infection should now be considered among differential diagnoses for patients from the midwestern United States who have signs and symptoms suggestive of tickborne illness. PMID:27434048

  1. Chromosome and Plasmids of the Tick-Borne Relapsing Fever Agent Borrelia hermsii

    PubMed Central

    2016-01-01

    The zoonotic pathogen Borrelia hermsii bears its multiple paralogous genes for variable antigens on several linear plasmids. Application of combined long-read and short-read next-generation sequencing provided complete sequences for antigen-encoding plasmids as well as other linear and circular plasmids and the linear chromosome of the genome. PMID:27284141

  2. Treatment with Doxycycline of Generalized Annular Elastolytic Giant Cell Granuloma Associated with Borrelia burgdorferi Infection

    PubMed Central

    Tas, B; Caglar, A; Ozdemir, B

    2015-01-01

    ABSTRACT This is a case of generalized annular elastolytic giant cell granuloma (AEGCG) associated with borrelia infection and genes of p-30, p-31, p-39. A possible cross-mediated reaction from the T-cell type which might have induced the AEGCG is discussed from the concept of “heat-shock proteins (HSPs) and molecular mimicry”. PMID:26624605

  3. Lyme Borrelia positive serology associated with spontaneous abortion in an endemic Italian area.

    PubMed

    Carlomagno, G; Luksa, V; Candussi, G; Rizzi, G M; Trevisan, G

    1988-01-01

    Lyme borreliosis acquired during pregnancy may be associated with stillbirth and fetal malformations. This paper reports preliminary results of a study intended to evaluate the frequency of Borrelia burgdorferi infection associated with spontaneous abortion in an endemic Italian area. PMID:3252658

  4. Role of outer membrane architecture in immune evasion by Treponema pallidum and Borrelia burgdorferi.

    PubMed

    Radolf, J D

    1994-09-01

    Combined ultrastructural and molecular studies have revealed that the syphilis and Lyme-disease spirochetes, Treponema pallidum and Borrelia burgdorferi, have distinctive molecular architectures. Both organisms persist in their hosts and have strategies for immune evasion that include the use of rare, poorly immunogenic surface-exposed proteins as potential virulence determinants. PMID:7812663

  5. Proteomic Analysis of Lyme Disease: Global Protein Comparison of Three Strains of Borrelia burgdorferi

    SciTech Connect

    Jacobs, Jon M.; Yang, Xiaohua; Luft, Benjamin J.; Dunn, John J.; Camp, David G.; Smith, Richard D.

    2005-04-01

    The Borrelia burgdorferi spirochete is the causative agent of Lyme disease, the most common tick-borne disease in the United States. It has been studied extensively to help understand its pathogenicity of infection and how it can persist in different mammalian hosts. We report the proteomic analysis of the archetype B. burgdorferi B31 strain and two other strains (ND40, and JD-1) having different Borrelia pathotypes using strong cation exchange fractionation of proteolytic peptides followed by high-resolution, reversed phase capillary liquid chromatography coupled with ion trap tandem mass spectrometric (LC-MS/MS) analysis. Protein identification was facilitated by the availability of the complete B31 genome sequence. A total of 665 Borrelia proteins were identified representing ~38 % coverage of the theoretical B31 proteome. A significant overlap was observed between the identified proteins in direct comparisons between any two strains (>72%), but distinct differences were observed among identified hypothetical and outer membrane proteins of the three strains. Such a concurrent proteomic overview of three Borrelia strains based upon only the B31 genome sequence is shown to provide significant insights into the presence or absence of specific proteins and a broad overall comparison among strains.

  6. Borrelia miyamotoi Infection in Patients from Upper Midwestern United States, 2014-2015.

    PubMed

    Jobe, Dean A; Lovrich, Steven D; Oldenburg, Darby G; Kowalski, Todd J; Callister, Steven M

    2016-08-01

    We confirmed Borrelia miyamotoi infection in 7 patients who had contracted an illness while near La Crosse, Wisconsin, USA, an area where Ixodes scapularis ticks are endemic. B. miyamatoi infection should now be considered among differential diagnoses for patients from the midwestern United States who have signs and symptoms suggestive of tickborne illness. PMID:27434048

  7. Potent activation of dopamine D3/D2 heterodimers by the antiparkinsonian agents, S32504, pramipexole and ropinirole.

    PubMed

    Maggio, Roberto; Scarselli, Marco; Novi, Francesca; Millan, Mark J; Corsini, Giovanni U

    2003-11-01

    Recombinant, human dopamine D3 and D2 receptors form functional heterodimers upon co-expression in COS-7 cells. Herein, actions of the antiparkinsonian agents, S32504, ropinirole and pramipexole, at D3/D2L heterodimers were compared to their effects at the respective monomers and at split, chimeric D3trunk/D2tail and D2trunk/D3tail receptors: the trunk incorporated transmembrane domains (TDs) I-V and the tail TDs VI and VII. In binding assays with the antagonist [3H]nemonapride, all agonists were potent ligands of D3 receptors showing, respectively, 100-, 18- and 56-fold lower affinity at D2L receptors, mimicking the selective D3 receptor antagonist, S33084 (100-fold). At D3trunk/D2tail receptors, except for ropinirole, all drugs showed lower affinities than at D3 sites, whereas for D2trunk/D3tail receptors, affinities of all drugs were higher than at D2L sites. The proportion of high affinity binding sites recognized by S32504, pramipexole and ropinirole in membranes derived from cells co-expressing D3 and D2L sites was higher than in an equivalent mixture of membranes from cells expressing D3 or D2L sites, consistent with the promotion of heterodimer formation. In contrast, the percentage of high and low affinity sites (biphasic isotherms) recognized by S33084 was identical. Functional actions were determined by co-transfection of a chimeric adenylyl cyclase (AC)-V/VI insensitive to D3 receptors. Accordingly, D3 receptor-transfected cells were irresponsive whereas, in D2L receptor-transfected cells, agonists suppressed forskolin-stimulated cAMP production with modest potencies. In cells co-transfected with D3 and D2L receptors, S32504, ropinirole and pramipexole potently suppressed AC-V/VI with EC50s 33-, 19- and 11-fold lower than at D2L receptors, respectively. S32504 also suppressed AC-V/VI activity at split D3trunk/D2tail and D2trunk/D3tail chimeras transfected into COS-7 cells. In conclusion, antiparkinson agents behave as potent agonists at D3/D2

  8. Transcriptional Profiling the 150 kb Linear Megaplasmid of Borrelia turicatae Suggests a Role in Vector Colonization and Initiating Mammalian Infection

    PubMed Central

    Wilder, Hannah K.; Raffel, Sandra J.; Barbour, Alan G.; Porcella, Stephen F.; Sturdevant, Daniel E.; Vaisvil, Benjamin; Kapatral, Vinayak; Schmitt, Daniel P.; Schwan, Tom G.; Lopez, Job E.

    2016-01-01

    Adaptation is key for survival as vector-borne pathogens transmit between the arthropod and vertebrate, and temperature change is an environmental signal inducing alterations in gene expression of tick-borne spirochetes. While plasmids are often associated with adaptation, complex genomes of relapsing fever spirochetes have hindered progress in understanding the mechanisms of vector colonization and transmission. We utilized recent advances in genome sequencing to generate the most complete version of the Borrelia turicatae 150 kb linear megaplasmid (lp150). Additionally, a transcriptional analysis of open reading frames (ORFs) in lp150 was conducted and identified regions that were up-regulated during in vitro cultivation at tick-like growth temperatures (22°C), relative to bacteria grown at 35°C and infected murine blood. Evaluation of the 3’ end of lp150 identified a cluster of ORFs that code for putative surface lipoproteins. With a microbe’s surface proteome serving important roles in pathogenesis, we confirmed the ORFs expression in vitro and in the tick compared to spirochetes infecting murine blood. Transcriptional evaluation of lp150 indicates the plasmid likely has essential roles in vector colonization and/or initiating mammalian infection. These results also provide a much needed transcriptional framework to delineate the molecular mechanisms utilized by relapsing fever spirochetes during their enzootic cycle. PMID:26845332

  9. Transcriptional Profiling the 150 kb Linear Megaplasmid of Borrelia turicatae Suggests a Role in Vector Colonization and Initiating Mammalian Infection.

    PubMed

    Wilder, Hannah K; Raffel, Sandra J; Barbour, Alan G; Porcella, Stephen F; Sturdevant, Daniel E; Vaisvil, Benjamin; Kapatral, Vinayak; Schmitt, Daniel P; Schwan, Tom G; Lopez, Job E

    2016-01-01

    Adaptation is key for survival as vector-borne pathogens transmit between the arthropod and vertebrate, and temperature change is an environmental signal inducing alterations in gene expression of tick-borne spirochetes. While plasmids are often associated with adaptation, complex genomes of relapsing fever spirochetes have hindered progress in understanding the mechanisms of vector colonization and transmission. We utilized recent advances in genome sequencing to generate the most complete version of the Borrelia turicatae 150 kb linear megaplasmid (lp150). Additionally, a transcriptional analysis of open reading frames (ORFs) in lp150 was conducted and identified regions that were up-regulated during in vitro cultivation at tick-like growth temperatures (22°C), relative to bacteria grown at 35°C and infected murine blood. Evaluation of the 3' end of lp150 identified a cluster of ORFs that code for putative surface lipoproteins. With a microbe's surface proteome serving important roles in pathogenesis, we confirmed the ORFs expression in vitro and in the tick compared to spirochetes infecting murine blood. Transcriptional evaluation of lp150 indicates the plasmid likely has essential roles in vector colonization and/or initiating mammalian infection. These results also provide a much needed transcriptional framework to delineate the molecular mechanisms utilized by relapsing fever spirochetes during their enzootic cycle. PMID:26845332

  10. Comparative Genome Hybridization Reveals Substantial Variation among Clinical Isolates of Borrelia burgdorferi Sensu Stricto with Different Pathogenic Properties

    PubMed Central

    Terekhova, Darya; Iyer, Radha; Wormser, Gary P.; Schwartz, Ira

    2006-01-01

    Clinical and murine studies suggest that there is a differential pathogenicity of different genotypes of Borrelia burgdorferi, the spirochetal agent of Lyme disease. Comparative genome hybridization was used to explore the relationship between different genotypes. The chromosomes of all studied isolates were highly conserved (>93%) with respect to both sequence and gene order. Plasmid sequences were substantially more diverse. Plasmids lp54, cp26, and cp32 were present in all tested isolates, and their sequences and gene order were conserved. The majority of linear plasmids showed variation both in terms of presence among different isolates and in terms of sequence and gene order. The data strongly imply that all B. burgdorferi clinical isolates contain linear plasmids related to each other, but the structure of these replicons may vary substantially from isolate to isolate. These alterations include deletions and presumed rearrangements that are likely to result in unique plasmid elements in many isolates. There is a strong correlation between complete genome hybridization profiles and other typing methods, which, in turn, also correlate to differences in pathogenicity. Because there is substantially less variation in the chromosomal and circular plasmid portions of the genome, the major differences in open reading frame content and genomic diversity among isolates are linear plasmid driven. PMID:16923879