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Ness S, Hilleringmann M. Streptococcus pneumoniae Type 1 Pilus - A Multifunctional Tool for Optimized Host Interaction. Front Microbiol 2021; 12:615924. [PMID: 33633703 PMCID: PMC7899983 DOI: 10.3389/fmicb.2021.615924] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 01/20/2021] [Indexed: 11/13/2022] Open
Abstract
Streptococcus pneumoniae represents a major Gram-positive human pathogen causing bacterial pneumonia, otitis media, meningitis, and other invasive diseases. Several pneumococcal isolates show increasing resistance rates against antibacterial agents. A variety of virulence factors promote pneumococcal pathogenicity with varying importance in different stages of host infection. Virulence related hair-like structures ("pili") are complex, surface located protein arrays supporting proper host interaction. In the last two decades different types of pneumococcal pili have been identified: pilus-1 (P1) and pilus-2 (P2) are formed by the catalytic activity of sortases that covalently assemble secreted polypeptide pilin subunits in a defined order and finally anchor the resulting pilus in the peptidoglycan. Within the long pilus fiber the presence of intramolecular isopeptide bonds confer high stability to the sequentially arranged individual pilins. This mini review will focus on S. pneumoniae TIGR4 P1 molecular architecture, the subunits it builds and provides insights into P1 sortase-mediated assembly. The complex P1 architecture (anchor-/backbone-/tip-subunits) allows the specific interaction with various target structures facilitating different steps of colonization, invasion and spreading within the host. Optimized pilin subunit confirmation supports P1 function under physiological conditions. Finally, aspects of P1- host interplay are summarized, including recent insights into P1 mechanobiology, which have important implications for P1 mediated pathogenesis.
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Affiliation(s)
| | - Markus Hilleringmann
- FG Protein Biochemistry & Cellular Microbiology, Department of Applied Sciences and Mechatronics, Munich University of Applied Sciences, Munich, Germany
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Polzer C, Ness S, Mohseni M, Kellerer T, Hilleringmann M, Rädler J, Hellerer T. Correlative two-color two-photon (2C2P) excitation STED microscopy. Biomed Opt Express 2019; 10:4516-4530. [PMID: 31565507 PMCID: PMC6757464 DOI: 10.1364/boe.10.004516] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/17/2019] [Accepted: 07/19/2019] [Indexed: 06/10/2023]
Abstract
We present a two-color two-photon stimulated emission depletion microscopy technique (2C2P-STED) that correlates a confocal image with a super-resolved image employing the inherent self-referencing mechanism of nonlinear excitation. The novel approach overcomes the substantial challenge posed by two different imaging modalities in laser-scanning fluorescence microscopy for colocalization on the nanometer scale. Demonstrating the principle of 2C2P-STED, we show for the first time super-resolved images of the gram-positive bacteria Streptococcus pneumoniae TIGR4 pilus type-1. A signal-to-noise ratio (SNR) greater than 10 was achieved in 2C2P excitation mode and approximately 70 nm details were resolved in 2P-STED.
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Affiliation(s)
- Christoph Polzer
- Multiphoton Imaging Lab, Munich University of Applied Sciences, 80335 Munich, Germany
- Faculty of Physics, Soft Condensed Matter, Ludwig-Maximilians-University, 80539 Munich, Germany
| | - Stefan Ness
- FG Protein Biochemistry & Cellular Microbiology, University of Applied Sciences Munich, 80335 Munich, Germany
| | - Mojtaba Mohseni
- Multiphoton Imaging Lab, Munich University of Applied Sciences, 80335 Munich, Germany
| | - Thomas Kellerer
- Multiphoton Imaging Lab, Munich University of Applied Sciences, 80335 Munich, Germany
| | - Markus Hilleringmann
- FG Protein Biochemistry & Cellular Microbiology, University of Applied Sciences Munich, 80335 Munich, Germany
| | - Joachim Rädler
- Faculty of Physics, Soft Condensed Matter, Ludwig-Maximilians-University, 80539 Munich, Germany
| | - Thomas Hellerer
- Multiphoton Imaging Lab, Munich University of Applied Sciences, 80335 Munich, Germany
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Becke TD, Ness S, Kaufmann BK, Hartmann B, Schilling AF, Sudhop S, Hilleringmann M, Clausen-Schaumann H. Pilus-1 Backbone Protein RrgB of Streptococcus pneumoniae Binds Collagen I in a Force-Dependent Way. ACS Nano 2019; 13:7155-7165. [PMID: 31184856 DOI: 10.1021/acsnano.9b02587] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Attachment to host tissue is a prerequisite for successful host colonization and invasion of pathogens. Many pathogenic bacteria use surface appendices, called pili, to bind and firmly attach to host tissue surfaces. Although it has been speculated that the laterally positioned D3 domain of the pilus-1 backbone protein RrgB of Streptococcus pneumoniae may promote bacterial-host interaction, via adhesion to extracellular matrix molecules, such as collagen, earlier studies showed no affinity of RrgB to collagen I. Using atomic force microscopy-based single molecule force spectroscopy combined with lateral force microscopy, we show that under mechanical load, RrgB in fact binds to human collagen I in a force-dependent manner. We observe exceptionally strong interactions, with interaction forces reaching as much as 1500 pN, and we show that high force loading and shearing rates enhance and further strengthen the interaction. In addition, the affinity of RrgB to collagen I under mechanical load not only depends on the orientation of the D3 domain but also on the orientation of the collagen fibrils, relative to the pulling direction. Both exceptionally high binding forces and force-induced bond strengthening resemble the behavior of so-called catch bonds, which have recently been observed in bacterial adhesins, but have not been reported for multimeric backbone subunits of virulence related pili.
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Affiliation(s)
- Tanja D Becke
- Center for Applied Tissue Engineering and Regenerative Medicine , Munich University of Applied Sciences , 80335 Munich , Germany
- Center for NanoScience , Ludwig-Maximilians-Universität München , 80799 Munich , Germany
| | - Stefan Ness
- FG Protein Biochemistry and Cellular Microbiology , Munich University of Applied Sciences , 80335 Munich , Germany
| | - Benedikt K Kaufmann
- Center for Applied Tissue Engineering and Regenerative Medicine , Munich University of Applied Sciences , 80335 Munich , Germany
- Center for NanoScience , Ludwig-Maximilians-Universität München , 80799 Munich , Germany
| | - Bastian Hartmann
- Center for Applied Tissue Engineering and Regenerative Medicine , Munich University of Applied Sciences , 80335 Munich , Germany
- Center for NanoScience , Ludwig-Maximilians-Universität München , 80799 Munich , Germany
| | - Arndt F Schilling
- Clinic for Trauma Surgery, Orthopaedics, and Plastic Surgery , University Medical Center Göttingen , 37075 Göttingen , Germany
| | - Stefanie Sudhop
- Center for Applied Tissue Engineering and Regenerative Medicine , Munich University of Applied Sciences , 80335 Munich , Germany
- Center for NanoScience , Ludwig-Maximilians-Universität München , 80799 Munich , Germany
| | - Markus Hilleringmann
- FG Protein Biochemistry and Cellular Microbiology , Munich University of Applied Sciences , 80335 Munich , Germany
| | - Hauke Clausen-Schaumann
- Center for Applied Tissue Engineering and Regenerative Medicine , Munich University of Applied Sciences , 80335 Munich , Germany
- Center for NanoScience , Ludwig-Maximilians-Universität München , 80799 Munich , Germany
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Wood M, Althorpe T, Hatch M, Ness S, McPhee R, Minchinson S. A multifactorial appraisal of injury data of upper hamstring and hip injuries in elite field hockey players. J Sci Med Sport 2018. [DOI: 10.1016/j.jsams.2018.09.183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Becke TD, Ness S, Sudhop S, Gaub HE, Hilleringmann M, Schilling AF, Clausen-Schaumann H. Covalent Immobilization of Proteins for the Single Molecule Force Spectroscopy. J Vis Exp 2018. [PMID: 30176022 PMCID: PMC6128213 DOI: 10.3791/58167] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
In recent years, atomic force microscopy (AFM) based single molecule force spectroscopy (SMFS) extended our understanding of molecular properties and functions. It gave us the opportunity to explore a multiplicity of biophysical mechanisms, e.g., how bacterial adhesins bind to host surface receptors in more detail. Among other factors, the success of SMFS experiments depends on the functional and native immobilization of the biomolecules of interest on solid surfaces and AFM tips. Here, we describe a straightforward protocol for the covalent coupling of proteins to silicon surfaces using silane-PEG-carboxyls and the well-established N-hydroxysuccinimid/1-ethyl-3-(3-dimethyl-aminopropyl)carbodiimid (EDC/NHS) chemistry in order to explore the interaction of pilus-1 adhesin RrgA from the Gram-positive bacterium Streptococcus pneumoniae (S. pneumoniae) with the extracellular matrix protein fibronectin (Fn). Our results show that the surface functionalization leads to a homogenous distribution of Fn on the glass surface and to an appropriate concentration of RrgA on the AFM cantilever tip, apparent by the target value of up to 20% of interaction events during SMFS measurements and revealed that RrgA binds to Fn with a mean force of 52 pN. The protocol can be adjusted to couple via site specific free thiol groups. This results in a predefined protein or molecule orientation and is suitable for other biophysical applications besides the SMFS.
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Affiliation(s)
- Tanja D Becke
- Center for Applied Tissue Engineering and Regenerative Medicine, Munich University of Applied Sciences; FG Protein Biochemistry & Cellular Microbiology, Munich University of Applied Sciences; Center for Nano Science, Ludwig-Maximilians-Universität München;
| | - Stefan Ness
- FG Protein Biochemistry & Cellular Microbiology, Munich University of Applied Sciences
| | - Stefanie Sudhop
- Center for Applied Tissue Engineering and Regenerative Medicine, Munich University of Applied Sciences; Center for Nano Science, Ludwig-Maximilians-Universität München
| | - Hermann E Gaub
- Center for Nano Science, Ludwig-Maximilians-Universität München
| | - Markus Hilleringmann
- FG Protein Biochemistry & Cellular Microbiology, Munich University of Applied Sciences
| | - Arndt F Schilling
- Klinik für Unfallchirurgie, Orthopädie und Plastische Chirurgie, University Medical Center Göttingen
| | - Hauke Clausen-Schaumann
- Center for Applied Tissue Engineering and Regenerative Medicine, Munich University of Applied Sciences; Center for Nano Science, Ludwig-Maximilians-Universität München
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Becke TD, Ness S, Gürster R, Schilling AF, di Guilmi AM, Sudhop S, Hilleringmann M, Clausen-Schaumann H. Single Molecule Force Spectroscopy Reveals Two-Domain Binding Mode of Pilus-1 Tip Protein RrgA of Streptococcus pneumoniae to Fibronectin. ACS Nano 2018; 12:549-558. [PMID: 29298375 DOI: 10.1021/acsnano.7b07247] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
For host cell adhesion and invasion, surface piliation procures benefits for bacteria. A detailed investigation of how pili adhere to host cells is therefore a key aspect in understanding their role during infection. Streptococcus pneumoniae TIGR 4, a clinical relevant serotype 4 strain, is capable of expressing pilus-1 with terminal RrgA, an adhesin interacting with host extracellular matrix (ECM) proteins. We used single molecule force spectroscopy to investigate the binding of full-length RrgA and single RrgA domains to fibronectin. Our results show that full-length RrgA and its terminal domains D3 and D4 bind to fibronectin with forces of 51.6 (full length), 52.8 (D3), and 46.2 pN (D4) at force-loading rates of around 1500 pN/s. Selective saturation of D3 and D4 binding sites on fibronectin showed that both domains can interact simultaneously with fibronectin, revealing a two-domain binding mechanism for the pilus-1 tip protein. The high off rates and the corresponding short lifetime of the RrgA Fn bond (τ = 0.26 s) may enable piliated pneumococci to form and maintain a transient contact to fibronectin-containing host surfaces and thus to efficiently scan the surface for specific receptors promoting host cell adhesion and invasion. These molecular properties could be essential for S. pneumoniae pili to mediate initial contact to the host cells and-shared with other piliated Gram-positive bacteria-favor host invasion.
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Affiliation(s)
- Tanja D Becke
- Department for Plastic Surgery and Hand Surgery, Klinikum Rechts der Isar, Technische Universität München , 81675 Munich, Germany
- Center for NanoScience, Ludwig-Maximilians-Universität München , 80799 Munich, Germany
| | | | | | - Arndt F Schilling
- Department for Plastic Surgery and Hand Surgery, Klinikum Rechts der Isar, Technische Universität München , 81675 Munich, Germany
- Klinik für Unfallchirurgie, Orthopädie und Plastische Chirurgie, University Medical Center Göttingen , 37075 Göttingen, Germany
| | | | - Stefanie Sudhop
- Center for NanoScience, Ludwig-Maximilians-Universität München , 80799 Munich, Germany
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Mittelman NS, Divers TJ, Engiles JB, Gerhold R, Ness S, Scrivani PV, Southard T, Johnson AL. Parelaphostrongylus tenuis Cerebrospinal Nematodiasis in a Horse with Cervical Scoliosis and Meningomyelitis. J Vet Intern Med 2017; 31:890-893. [PMID: 28317172 PMCID: PMC5435076 DOI: 10.1111/jvim.14691] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 01/16/2017] [Accepted: 02/14/2017] [Indexed: 11/28/2022] Open
Abstract
There are reports of horses with acute onset acquired cervical scoliosis and cutaneous analgesia. The underlying dorsal gray column myelitis that produces these neurologic signs has been only presumptively attributed to migration of Parelaphostrongylus tenuis within the spinal cord. Despite previous confirmation brain by polymerase chain reaction testing, of P. tenuis within the brain of horses by polymerase chain reaction testing, genetic testing has failed to definitively identify the presence of this parasite in cases of equine myelitis. This case report provides molecular confirmation via polymerase chain reaction of P. tenuis within the cervical spinal cord of a horse with scoliosis and cutaneous analgesia.
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Affiliation(s)
- N S Mittelman
- New Bolton Center at the University of Pennsylvania School of Veterinary Medicine Kennett Square, PA
| | - T J Divers
- Cornell University College of Veterinary Medicine Equine and Farm Animal Hospital, Ithaca, NY
| | - J B Engiles
- New Bolton Center at the University of Pennsylvania School of Veterinary Medicine Kennett Square, PA
| | - R Gerhold
- University of Tennessee College of Veterinary Medicine, Knoxville, TN
| | - S Ness
- Cornell University College of Veterinary Medicine Equine and Farm Animal Hospital, Ithaca, NY
| | - P V Scrivani
- Cornell University College of Veterinary Medicine Equine and Farm Animal Hospital, Ithaca, NY
| | - T Southard
- Cornell University College of Veterinary Medicine Equine and Farm Animal Hospital, Ithaca, NY
| | - A L Johnson
- New Bolton Center at the University of Pennsylvania School of Veterinary Medicine Kennett Square, PA
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Novotny E, Renfroe B, Yardi N, Nordli D, Ness S, Wang S, Weber T, Kurland CL, Yuen E, Eerdekens M, Venkatraman L, Nye JS, Ford L. Randomized trial of adjunctive topiramate therapy in infants with refractory partial seizures. Neurology 2010; 74:714-20. [PMID: 20089937 DOI: 10.1212/wnl.0b013e3181d1cd4c] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To evaluate the efficacy and safety of adjunctive topiramate (sprinkle capsules or oral liquid) in reducing daily rates of partial-onset seizures (POS) in infants with refractory POS. METHODS In this double-blind, placebo-controlled, parallel-group, international study, infants (n = 149) with clinical or EEG evidence of refractory POS were randomly allocated (1:1:1:1) to receive adjunctive topiramate 5, 15, or 25 mg/kg/d or placebo for 20 days. The primary variable was the median percentage reductions in daily POS rate from baseline to final assessment as recorded on a 48-hour video-EEG. RESULTS Of the 149 infants (mean age 12 months) included in the intent-to-treat analysis set, 130 completed the study. Median percentage reduction from baseline in daily POS rate was not significantly different (p = 0.97) between topiramate 25 mg/kg (20.4%) and placebo (13.1%). Lower doses were not formally tested, but nominal p values for comparisons with placebo were not significant (15-mg/kg/d dose: p = 0.97; 5-mg/kg/d dose: p = 0.91). Treatment-emergent fever, diarrhea, vomiting, anorexia, weight decrease, somnolence, and viral infection occurred more frequently (> or = 10% difference) with topiramate than with placebo. CONCLUSION In infants aged 1-24 months, topiramate 5, 15, or 25 mg/kg/d was not effective as adjunctive treatment for refractory partial-onset seizures. No new safety concerns associated with topiramate use were noted. CLASSIFICATION OF EVIDENCE This interventional study provides Class I evidence that topiramate 5, 15, or 25 mg/kg/d compared with placebo does not significantly reduce seizure rates in infants aged 1 month to 2 years with refractory partial-onset seizures.
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Affiliation(s)
- E Novotny
- University of Washington, Seattle, WA, USA.
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9
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Ness S, de Graaff RAG, Abrahams JP, Pannu NS. CRANK - new methods for automated structure solution. Acta Crystallogr A 2004. [DOI: 10.1107/s0108767304099702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Ness S, Martin R, Kindler AM, Paetzel M, Gold M, Jensen SE, Jones JB, Strynadka NC. Structure-based design guides the improved efficacy of deacylation transition state analogue inhibitors of TEM-1 beta-Lactamase(,). Biochemistry 2000; 39:5312-21. [PMID: 10820001 DOI: 10.1021/bi992505b] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Transition state analogue boronic acid inhibitors mimicking the structures and interactions of good penicillin substrates for the TEM-1 beta-lactamase of Escherchia coli were designed using graphic analyses based on the enzyme's 1.7 A crystallographic structure. The synthesis of two of these transition state analogues, (1R)-1-phenylacetamido-2-(3-carboxyphenyl)ethylboronic acid (1) and (1R)-1-acetamido-2-(3-carboxy-2-hydroxyphenyl)ethylboronic acid (2), is reported. Kinetic measurements show that, as designed, compounds 1 and 2 are highly effective deacylation transition state analogue inhibitors of TEM-1 beta-lactamase, with inhibition constants of 5.9 and 13 nM, respectively. These values identify them as among the most potent competitive inhibitors yet reported for a beta-lactamase. The best inhibitor of the current series was (1R)-1-phenylacetamido-2-(3-carboxyphenyl)ethylboronic acid (1, K(I) = 5.9 nM), which resembles most closely the best known substrate of TEM-1, benzylpenicillin (penicillin G). The high-resolution crystallographic structures of these two inhibitors covalently bound to TEM-1 are also described. In addition to verifying the design features, these two structures show interesting and unanticipated changes in the active site area, including strong hydrogen bond formation, water displacement, and rearrangement of side chains. The structures provide new insights into the further design of this potent class of beta-lactamase inhibitors.
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Affiliation(s)
- S Ness
- Department of Biochemistry and Molecular Biology, University of British Columbia, 2146 Health Sciences Mall, Vancouver, British Columbia, Canada
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Zagariya A, Mungre S, Lovis R, Birrer M, Ness S, Thimmapaya B, Pope R. Tumor necrosis factor alpha gene regulation: enhancement of C/EBPbeta-induced activation by c-Jun. Mol Cell Biol 1998; 18:2815-24. [PMID: 9566900 PMCID: PMC110660 DOI: 10.1128/mcb.18.5.2815] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/1997] [Accepted: 02/12/1998] [Indexed: 02/07/2023] Open
Abstract
Tumor necrosis factor alpha (TNF alpha) is a key regulatory cytokine whose expression is controlled by a complex set of stimuli in a variety of cell types. Previously, we found that the monocyte/macrophage-enriched nuclear transcription factor C/EBPbeta played an important role in the regulation of the TNF alpha gene in myelomonocytic cells. Abundant evidence suggests that other transcription factors participate as well. Here we have analyzed interactions between C/EBPbeta and c-Jun, a component of the ubiquitously expressed AP-1 complex. In phorbol myristate acetate (PMA)-treated Jurkat T cells, which did not possess endogenous C/EBPbeta, expression of c-Jun by itself had relatively little effect on TNF alpha promoter activity. However, the combination of C/EBPbeta and c-Jun was synergistic, resulting in greater than 130-fold activation. This effect required both the leucine zipper and DNA binding domains, but not the transactivation domain, of c-Jun, plus the AP-1 binding site centered 102/103 bp upstream of the transcription start site in the TNF alpha promoter. To determine if C/EBPbeta and c-Jun might cooperate to regulate the cellular TNF alpha gene in myelomonocytic cells, U937 cells that possess endogenous C/EBPbeta and were stably transfected with either wild-type c-Jun or the transactivation domain deletion mutant (TAM-67) were examined. U937 cells expressing ectopic wild-type c-Jun or TAM-67 secreted over threefold more TNF alpha than the control line in response to PMA plus lipopolysaccharide. Transient transfection of the U937 cells expressing TAM-67 suggested that TAM-67 binding to the -106/-99-bp AP-1 binding site cooperated with endogenous C/EBPbeta in the activation of the -120 TNF alpha promoter-reporter. DNA binding assays using oligonucleotides derived from the TNF alpha promoter suggested that C/EBPbeta and c-Jun interact in vitro and that the interaction may be DNA dependent. Our data demonstrate that the TNF alpha gene is regulated by the interaction of the ubiquitous AP-1 complex protein c-Jun and the monocyte/macrophage-enriched transcription factor C/EBPbeta and that this interaction contributes to the expression of the cellular TNF alpha gene in myelomonocytic cells. This interaction was unique in that it did not require the c-Jun transactivation domain, providing new insight into the cell-type-specific regulation of the TNF alpha gene.
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Affiliation(s)
- A Zagariya
- Department of Medicine, and Veterans Administration Lakeside Medical Center, Northwestern University Medical School, Chicago, Illinois 60611, USA
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12
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Abstract
The magnetic resonance absorption spectrum, T1 and T2 relaxation time distributions, and magnetization transfer properties of ex vivo breast tissue have been characterized at 1.5 T and 37 degrees C. The fraction of fibroglandular tissue within individual tissue samples (n = 31) was inferred from the tissue volumetric water content obtained by integration of resolvable broad-line fat and water resonances. The spectroscopically estimated water content was strongly correlated with that extracted enzymatically (Pearson correlation coefficient 0.98, P < < 0.01), which enabled the assignment of principal relaxation components for fibroglandular tissue (T2=0.04+/-0.01, T1=1.33+/-0.24 s), and for adipose tissue (T2=0.13+/-0.01, T1=0.23+/-0.01 s, and T2=0.38+/-0.03, T1=0.62+/-0.16 s). Th e relaxation components for fibroglandular tissue exhibited strong magnetization transfer, whereas those for adipose tissue showed little magnetization transfer effect. These results ultimately have applicability to the optimization of clinical magnetic resonance imaging and research investigations of the breast.
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Affiliation(s)
- S J Graham
- Department of Medical Biophysics, University of Toronto, Ontario, Canada
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Abstract
OBJECTIVE Using a novel minimally invasive (< or = 1.4 mm) technique to sample minuscule (0.5 microliter) amounts of dermal interstitial fluid (ISF), we assessed the accuracy of its glucose concentrations in predicting concurrently measured venous plasma and capillary plasma glucose concentrations. RESEARCH DESIGN AND METHODS A total of 67 adult (37 male and 30 female) volunteers (57 with and 10 without diabetes) with venous plasma glucose levels from 1.6 to 28.4 mmol/l underwent forearm ISF, antecubetal venous, and fingertip capillary sampling. RESULTS Rank correlations were 0.974 for ISF 1 vs. 2, 0.954 for ISF vs. venous, 0.935 for ISF vs. capillary, and 0.987 for venous vs. capillary. Median absolute differences were 0.53 mmol/l for ISF 1 vs. 2, 1.33 mmol/l for ISF vs. venous, 1.06 mmol/l for ISF vs. capillary, and 0.56 mmol/l for capillary vs. venous. Equations expressing ISF glucose as a function of venous and capillary glucose and equations expressing capillary glucose as a function of venous glucose had slopes of 0.995, 0.936, and 1.021, respectively (none significantly different from unity), and intercepts of 1.03 mmol/l (P = 0.024), 0.94 mmol/l (P = 0.131), and 0.56 mmol/l (P = 0.041), respectively. Error grid analysis of ISF vs. venous glucose and of capillary vs. venous glucose showed that 97% of the measurements fell within grids A and B. CONCLUSIONS Dermal ISF sampling is a bloodless minimally invasive technique that provides a medium for glucose measurement, the concentrations of which closely reflect ambient glycemia to a degree comparable with that of capillary glucose measurements.
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Affiliation(s)
- F J Service
- Division of Endocrinology, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA.
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Ness S, Hart T, Read R. GAMMA: a new docking program utilizing an advanced evolution system algorithm as an engine. Acta Crystallogr A 1996. [DOI: 10.1107/s0108767396095499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Abstract
The C11A mutant of SV40 large T antigen is unable to support the replication of viral origin containing DNA (ori-DNA) in vivo or in vitro. The mutation within C11A at residue 522 (pro-->ser) is located within the presumptive ATPase region of T antigen. While C11A T antigen was previously reported to be defective in ATPase and DNA helicase activities, it was shown to be capable of binding specifically to DNA containing the viral replication origin. As the positions of many conditional mutations of SV40 T antigen are located within the ATPase domain we asked whether C11A might also exhibit temperature-sensitive defects. We found that several activities of C11A T antigen are conditionally defective. C11A T antigen was able to hydrolyze ATP, assemble into hexamers, and display ATP-dependent alterations in DNA binding and ori-DNA structure at 33 degrees but not 41 degrees. Wild-type T antigen did not exhibit temperature-sensitive defects in these activities. C11A T antigen was completely unable to unwind ori-DNA at either temperature. This defect in unwinding was trans-dominant; C11A T antigen inhibited ori-DNA unwinding by wild-type T antigen. These data show that a mutant displaying a nonconditional defective phenotype may contain a subset of relevant properties that are temperature sensitive.
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Affiliation(s)
- H E Lorimer
- Department of Biological Sciences, Columbia University, New York, New York 10027
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Fuerstenberg S, Beug H, Introna M, Khazaie K, Muñoz A, Ness S, Nordström K, Sap J, Stanley I, Zenke M. Ectopic expression of the erythrocyte band 3 anion exchange protein, using a new avian retrovirus vector. J Virol 1990; 64:5891-902. [PMID: 2173771 PMCID: PMC248754 DOI: 10.1128/jvi.64.12.5891-5902.1990] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
A retrovirus vector was constructed from the genome of avian erythroblastosis virus ES4. The v-erbA sequences of avian erythroblastosis virus were replaced by those coding for neomycin phosphotransferase, creating a gag-neo fusion protein which provides G418 resistance as a selectable marker. The v-erbB sequences following the splice acceptor were replaced by a cloning linker allowing insertion of foreign genes. The vector has been tested in conjunction with several helper viruses for the transmission of G418 resistance, titer, stability, transcription, and the transduction and expression of foreign genes in both chicken embryo fibroblasts and the QT6 quail cell line. The results show that the vector is capable of producing high titers of Neor virus from stably integrated proviruses. These proviruses express a balanced ratio of genome length to spliced transcripts which are efficiently translated into protein. Using the Escherichia coli beta-galactosidase gene cloned into the vector as a test construct, expression of enzyme activity could be detected in 90 to 95% of transfected target cells and in 80 to 85% of subsequently infected cells. In addition, a cDNA encoding the avian erythrocyte band 3 anion exchange protein has been expressed from the vector in both chicken embryo fibroblasts and QT6 cells and appears to function as an active, plasma membrane-based anion transporter. The ectopic expression of band 3 protein provides a visual marker for vector function in these cells.
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Affiliation(s)
- S Fuerstenberg
- Department of Molecular Biology, Karolinska Institute, Stockholm, Sweden
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17
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Leutz A, Damm K, Sterneck E, Kowenz E, Ness S, Frank R, Gausepohl H, Pan YC, Smart J, Hayman M. Molecular cloning of the chicken myelomonocytic growth factor (cMGF) reveals relationship to interleukin 6 and granulocyte colony stimulating factor. EMBO J 1989; 8:175-81. [PMID: 2785450 PMCID: PMC400787 DOI: 10.1002/j.1460-2075.1989.tb03362.x] [Citation(s) in RCA: 106] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Normal as well as retrovirally transformed avian myeloid precursor cells require the colony stimulating factor cMGF for their survival, proliferation and colony formation in vitro. cMGF has been shown to be a glycoprotein which is active in the picomolar concentration range. Co-expression of kinase type oncogenes in v-myb or v-myc transformed myeloid cells induces cMGF expression and confers factor independence via an autocrine mechanism. Here we describe the molecular cloning of cMGF from a myeloblast cDNA library and show that it is a 201 amino acid residue secretory protein which is modified by signal peptide cleavage and glycosylation during translocation into the lumen of membrane vesicles. A bacterially expressed trpE-cMGF fusion protein induces proliferation of E26 transformed myeloblasts in a cMGF bioassay suggesting that glycosylation is not absolutely necessary for biological activity. Sequence comparison reveals that cMGF is distantly related to G-CSF and IL-6.
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Affiliation(s)
- A Leutz
- European Molecular Biology Laboratory, Heidelberg, FRG
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18
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Christie KE, Håvarstein LS, Djupvik HO, Ness S, Endresen C. Characterization of a new serotype of infectious pancreatic necrosis virus isolated from Atlantic salmon. Arch Virol 1988; 103:167-77. [PMID: 3214272 DOI: 10.1007/bf01311090] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Virus particles isolated from hatchery reared fish with infectious pancreatic necrosis (IPN) were neutralized by homologous immune sera but not by immune sera raised against IPN virus serotype 1, 2, and 3. This virus isolate, called the N1 strain, was detected in one year old Atlantic salmon (Salmo salar) during an outbreak with histopathological lesions of IPN and slightly increased mortality. The polypeptide pattern of N1 virus differed markedly from that of the three classical IPN virus serotypes. Double stranded RNA isolated from the N1 virus particles, co-migrated during agarose gel electrophoresis with nucleic acid isolated from the IPN virus Jasper and Ab strains. Nucleic acid hybridizations using low stringency washing conditions and a synthetic DNA oligonucleotide probe (representing the 3' end of the A segment of the Jasper strain) gave positive results with the IPN virus Jasper, Ab, Sp, and N1 strains. The results presented in this paper show that the N1 isolate differs immunologically and biochemically from the IPN virus serotypes 1, 2, and 3 and may represent a new serotype of IPNV.
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Affiliation(s)
- K E Christie
- Norbio A/S, Lab. of Biotechnology, University of Bergen, Norway
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19
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Hobbs B, Ness S. Rationale for and long term care of indwelling arterial infusion systems. Oncol Nurs Forum 1977; 4:6-7. [PMID: 247475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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