scholarly journals Glycerol Monolaurate Inhibits Virulence Factor Production in Bacillus anthracis

2005 ◽  
Vol 49 (4) ◽  
pp. 1302-1305 ◽  
Author(s):  
Sara M. Vetter ◽  
Patrick M. Schlievert
Keyword(s):  
Bacillus Anthracis ◽  
Protective Antigen ◽  
Polyacrylamide Gel Electrophoresis ◽  
Lethal Factor ◽  
Sodium Dodecyl ◽  
The United States ◽  
Human Populations ◽  
Transcriptional Level ◽  
Mrna Levels ◽  
Glycerol Monolaurate

ABSTRACT Anthrax, caused by Bacillus anthracis, has been brought to the public's attention because of the 2001 bioterrorism attacks. However, anthrax is a disease that poses agricultural threats in the United States as well as human populations in Europe, China, Africa, and Australia. Glycerol monolaurate (GML) is a compound that has been shown to inhibit exotoxin production by Staphylococcus aureus and other gram-positive bacteria. Here, we study the effects of GML on growth and toxin production in B. anthracis. The Sterne strain of B. anthracis was grown to post-exponential phase with 0-, 10-, 15-, or 20-μg/ml concentrations of GML and then assayed quantitatively for protective antigen (PA) and lethal factor (LF). After 8 h, GML at concentrations greater than 20 μg/ml was bacteriostatic to growth of the organism. However, a 10-μg/ml concentration of GML was not growth inhibitory, but amounts of PA and LF made were greatly reduced. This effect was not global for all proteins when total secreted protein from culture fluids was examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Through quantitative reverse transcription-PCR assays, this toxin-inhibitory effect was shown to occur at the transcriptional level, since amounts of mRNA for pagA (PA), lef (LF), and cya (edema factor) were reduced. Surprisingly, mRNA levels of atxA, a regulator of exotoxin gene expression, rose in the presence of GML. These data will be useful in developing therapeutic tools to treat anthrax disease, whether in animals or humans. These results also suggest that mechanisms of virulence regulation exist independent of atxA.

scholarly journals Expression and Purification of the Recombinant Lethal Factor of Bacillus anthracis

1998 ◽  
Vol 66 (2) ◽  
pp. 862-865 ◽  
Author(s):  
Pankaj Gupta ◽  
Smriti Batra ◽  
Arun P. Chopra ◽  
Yogendra Singh ◽  
Rakesh Bhatnagar
Keyword(s):  
Bacillus Anthracis ◽  
Protective Antigen ◽  
Polyacrylamide Gel Electrophoresis ◽  
Lethal Factor ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Nitrilotriacetic Acid ◽  
Biologically Active ◽  
Liquid Chromatograph ◽  
E Coli

ABSTRACT The structural gene for the 90-kDa lethal factor (LF) isolated fromBacillus anthracis was expressed as a fusion protein with six histidine residues in Escherichia coli. Expression of LF in E. coli under the transcriptional regulation of the T5 promoter yielded a soluble cytosolic protein with an apparent molecular mass of 90 kDa, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Recombinant LF reacted with anti-LF antibodies. The protein was purified to homogeneity by nickel nitrilotriacetic acid affinity chromatography and gel filtration on a Sephacryl S-200 column followed by anion exchange on a fast-performance liquid chromatograph with a Resource-Q column. The yield of purified LF from this procedure was 1.5 mg/liter. In solution, trypsin cleaved protective antigen bound to native and recombinant LF with comparable affinities. In macrophage lysis assays, native and recombinant LF exhibited identical potencies. The results suggest that large amounts of biologically active LF can be purified by this procedure.

Fermentation, Purification, and Characterization of Protective Antigen from a Recombinant, Avirulent Strain ofBacillus anthracis

1998 ◽  
Vol 64 (3) ◽  
pp. 982-991 ◽  
Author(s):  
J. W. Farchaus ◽  
W. J. Ribot ◽  
S. Jendrek ◽  
S. F. Little
Keyword(s):  
Gel Electrophoresis ◽  
Protective Antigen ◽  
Polyacrylamide Gel Electrophoresis ◽  
Lethal Factor ◽  
Sodium Dodecyl ◽  
The United States ◽  
Reversed Phase ◽  
Avirulent Strain ◽  
Purification And Characterization

ABSTRACT Bacillus anthracis, the etiologic agent for anthrax, produces two bipartite, AB-type exotoxins, edema toxin and lethal toxin. The B subunit of both exotoxins is an M r83,000 protein termed protective antigen (PA). The human anthrax vaccine currently licensed for use in the United States consists primarily of this protein adsorbed onto aluminum oxyhydroxide. This report describes the production of PA from a recombinant, asporogenic, nontoxigenic, and nonencapsulated host strain of B. anthracis and the subsequent purification and characterization of the protein product. Fermentation in a high-tryptone, high-yeast-extract medium under nonlimiting aeration produced 20 to 30 mg of secreted PA per liter. Secreted protease activity under these fermentation conditions was low and was inhibited more than 95% by the addition of EDTA. A purity of 88 to 93% was achieved for PA by diafiltration and anion-exchange chromatography, while greater than 95% final purity was achieved with an additional hydrophobic interaction chromatography step. The purity of the PA product was characterized by reversed-phase high-pressure liquid chromatography, sodium dodecyl sulfate (SDS)-capillary electrophoresis, capillary isoelectric focusing, native gel electrophoresis, and SDS-polyacrylamide gel electrophoresis. The biological activity of the PA, when combined with excess lethal factor in the macrophage cell lysis assay, was comparable to previously reported values.

scholarly journals Metalloproteinase Inhibitors, Nonantimicrobial Chemically Modified Tetracyclines, and Ilomastat Block Bacillus anthracis Lethal Factor Activity in Viable Cells

2005 ◽  
Vol 73 (11) ◽  
pp. 7548-7557 ◽  
Author(s):  
Salih S. Kocer ◽  
Stephen G. Walker ◽  
Brad Zerler ◽  
Lorne M. Golub ◽  
Sanford R. Simon
Keyword(s):  
Bacillus Anthracis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Lethal Factor ◽  
Sodium Dodecyl ◽  
Viable Cell ◽  
Lethal Toxin ◽  
Mitogen Activated Protein Kinase ◽  
Metalloproteinase Inhibitors ◽  
Mitogen Activated Protein ◽  
Chemically Modified Tetracyclines

ABSTRACT Lethal toxin, produced by the bacterium Bacillus anthracis, is a major contributor to morbidity and mortality in animals and humans who have contracted anthrax. One component of this toxin, lethal factor (LF), proteolytically inactivates members of the mitogen-activated protein kinase kinase (MAPKK or MEK) family. In this study we show that CMT-300, CMT-308, and Ilomastat, agents initially characterized as matrix metalloproteinase inhibitors which are in early stages of development as pharmaceuticals, effectively inhibit the zinc metalloproteinase activity of LF. All three inhibitors, CMT-300, CMT-308, and Ilomastat, inhibit LF-mediated cleavage of a synthetic peptide substrate based on the N-terminal domain of MEKs. Inhibition of LF-mediated MEK proteolysis by all three agents was also achieved using lysates of the human monocytoid line MonoMac 6 as sources of MAPKKs and visualization of the extent of cleavage after separation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by detection by Western blotting. Finally, we have demonstrated inhibition of intracellular MEKs in viable human monocytes and MonoMac 6 cells by these agents after incubation of the cells with a reconstituted preparation of recombinant lethal toxin. All three agents are effective inhibitors when incubated with LF prior to exposure to cells, while the CMTs, but not Ilomastat, are also effective when added after LF has already entered the viable cell targets. These results offer promise for strategies to combat effects of the lethal toxin of B. anthracis.

scholarly journals Study of Immunization against Anthrax with the Purified Recombinant Protective Antigen of Bacillus anthracis

1998 ◽  
Vol 66 (7) ◽  
pp. 3447-3448 ◽  
Author(s):  
Yogendra Singh ◽  
Bruce E. Ivins ◽  
Stephen H. Leppla
Keyword(s):  
Biological Activity ◽  
Bacillus Anthracis ◽  
Guinea Pigs ◽  
Protective Antigen ◽  
Lethal Factor ◽  
The United States ◽  
Anthrax Toxin ◽  
Local Pain ◽  
Edema Factor ◽  
Recombinant Protective Antigen

ABSTRACT Protective antigen (PA) of anthrax toxin is the major component of human anthrax vaccine. Currently available human vaccines in the United States and Europe consist of alum-precipitated supernatant material from cultures of toxigenic, nonencapsulated strains of Bacillus anthracis. Immunization with these vaccines requires several boosters and occasionally causes local pain and edema. We previously described the biological activity of a nontoxic mutant of PA expressed in Bacillus subtilis. In the present study, we evaluated the efficacy of the purified mutant PA protein alone or in combination with the lethal factor and edema factor components of anthrax toxin to protect against anthrax. Both mutant and native PA preparations elicited high anti-PA titers in Hartley guinea pigs. Mutant PA alone and in combination with lethal factor and edema factor completely protected the guinea pigs from B. anthracis spore challenge. The results suggest that the mutant PA protein may be used to develop an effective recombinant vaccine against anthrax.

The Recovery of Factor VIII from Fresh-Frozen, Indated and Outdated Human Plasma

1976 ◽  
Vol 36 (01) ◽  
pp. 071-077 ◽  
Author(s):  
Daniel E. Whitman ◽  
Mary Ellen Switzer ◽  
Patrick A. McKee
Keyword(s):  
Factor Viii ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
The United States ◽  
Fresh Frozen Plasma ◽  
Red Cross ◽  
Random Samples ◽  
Fresh Frozen ◽  
Factor Viii Concentrates ◽  
Frozen Plasma

SummaryThe availability of factor VIII concentrates is frequently a limitation in the management of classical hemophilia. Such concentrates are prepared from fresh or fresh-frozen plasma. A significant volume of plasma in the United States becomes “indated”, i. e., in contact with red blood cells for 24 hours at 4°, and is therefore not used to prepare factor VIII concentrates. To evaluate this possible resource, partially purified factor VIII was prepared from random samples of fresh-frozen, indated and outdated plasma. The yield of factor VIII protein and procoagulant activity from indated plasma was about the same as that from fresh-frozen plasma. The yield from outdated plasma was substantially less. After further purification, factor VIII from the three sources gave a single subunit band when reduced and analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. These results indicate that the approximately 287,000 liters of indated plasma processed annually by the American National Red Cross (ANRC) could be used to prepare factor VIII concentrates of good quality. This resource alone could quadruple the supply of factor VIII available for therapy.

scholarly journals Detection of Anthrax Toxin in the Serum of Animals Infected with Bacillus anthracis by Using Engineered Immunoassays

2006 ◽  
Vol 13 (6) ◽  
pp. 671-677 ◽  
Author(s):  
Robert Mabry ◽  
Kathleen Brasky ◽  
Robert Geiger ◽  
Ricardo Carrion ◽  
Gene B. Hubbard ◽  
...  
Keyword(s):  
Bacillus Anthracis ◽  
Protective Antigen ◽  
Lethal Factor ◽  
Systemic Circulation ◽  
Rapid Identification ◽  
Anthrax Toxin ◽  
Soluble Form ◽  
Before And After

ABSTRACT Several strategies that target anthrax toxin are being developed as therapies for infection by Bacillus anthracis. Although the action of the tripartite anthrax toxin has been extensively studied in vitro, relatively little is known about the presence of toxins during an infection in vivo. We developed a series of sensitive sandwich enzyme-linked immunosorbent assays (ELISAs) for detection of both the protective antigen (PA) and lethal factor (LF) components of the anthrax exotoxin in serum. The assays utilize as capture agents an engineered high-affinity antibody to PA, a soluble form of the extracellular domain of the anthrax toxin receptor (ANTXR2/CMG2), or PA itself. Sandwich immunoassays were used to detect and quantify PA and LF in animals infected with the Ames or Vollum strains of anthrax spores. PA and LF were detected before and after signs of toxemia were observed, with increasing levels reported in the late stages of the infection. These results represent the detection of free PA and LF by ELISA in the systemic circulation of two animal models exposed to either of the two fully virulent strains of anthrax. Simple anthrax toxin detection ELISAs could prove useful in the evaluation of potential therapies and possibly as a clinical diagnostic to complement other strategies for the rapid identification of B. anthracis infection.

scholarly journals Injection of Staphylococcus aureus EDIN by the Bacillus anthracis Protective Antigen Machinery Induces Vascular Permeability

2009 ◽  
Vol 77 (9) ◽  
pp. 3596-3601 ◽  
Author(s):  
Monica Rolando ◽  
Patrick Munro ◽  
Caroline Stefani ◽  
Patrick Auberger ◽  
Gilles Flatau ◽  
...  
Keyword(s):  
Bacillus Anthracis ◽  
Vascular Permeability ◽  
Protective Antigen ◽  
Lethal Factor ◽  
Vascular Leakage ◽  
Host Cells ◽  
Mitogen Activated Protein Kinase ◽  
Systemic Injection ◽  
Pulmonary Endothelium ◽  
Endothelium Permeability

ABSTRACT Systemic injection of Bacillus anthracis lethal toxin (LT) produces vascular leakage and animal death. Recent studies suggest that LT triggers direct endothelial cell cytotoxicity that is responsible for the vascular leakage. LT is composed of heptamers of protective antigen (PA), which drives the endocytosis and translocation into host cells of the lethal factor (LF), a mitogen-activated protein kinase kinase protease. Here we investigated the consequences of injection of an endothelium-permeabilizing factor using LT as a “molecular syringe.” To this end, we generated the chimeric factor LE, corresponding to the PA-binding domain of LF (LF1-254) fused to EDIN exoenzyme. EDIN ADP ribosylates RhoA, leading to actin cable disruption and formation of transcellular tunnels in endothelial cells. We report that systemic injection of LET (LE plus PA) triggers a PA-dependent increase in the pulmonary endothelium permeability. We also report that native LT induces a progressive loss of endothelium barrier function. We established that there is a direct correlation between the extent of endothelium permeability induced by LT and the cytotoxic activity of LT. This suggests new ways to design therapeutic drugs against anthrax directed toward vascular permeability.

scholarly journals Comparative Secretome Analyses of Three Bacillus anthracis Strains with Variant Plasmid Contents

2005 ◽  
Vol 73 (6) ◽  
pp. 3646-3658 ◽  
Author(s):  
Janine M. Lamonica ◽  
MaryAnn Wagner ◽  
Michel Eschenbrenner ◽  
Leanne E. Williams ◽  
Tabbi L. Miller ◽  
...  
Keyword(s):  
Bacillus Anthracis ◽  
Protective Antigen ◽  
Isocitrate Lyase ◽  
Lethal Factor ◽  
Protein A ◽  
Surface Protein ◽  
Computer Assisted ◽  
Two Dimensional Gel Electrophoresis ◽  
Peptide Mass ◽  
Proteomic Approach

ABSTRACT Bacillus anthracis, the causative agent of anthrax, secretes numerous proteins into the extracellular environment during infection. A comparative proteomic approach was employed to elucidate the differences among the extracellular proteomes (secretomes) of three isogenic strains of B. anthracis that differed solely in their plasmid contents. The strains utilized were the wild-type virulent B. anthracis RA3 (pXO1+ pXO2+) and its two nonpathogenic derivative strains: the toxigenic, nonencapsulated RA3R (pXO1+ pXO2−) and the totally cured, nontoxigenic, nonencapsulated RA3:00 (pXO1− pXO2−). Comparative proteomics using two-dimensional gel electrophoresis followed by computer-assisted gel image analysis was performed to reveal unique, up-regulated, or down-regulated secretome proteins among the strains. In total, 57 protein spots, representing 26 different proteins encoded on the chromosome or pXO1, were identified by peptide mass fingerprinting. S-layer-derived proteins, such as Sap and EA1, were most frequently observed. Many sporulation-associated enzymes were found to be overexpressed in strains containing pXO1+. This study also provides evidence that pXO2 is necessary for the maximal expression of the pXO1-encoded toxins lethal factor (LF), edema factor (EF), and protective antigen (PA). Several newly identified putative virulence factors were observed; these include enolase, a high-affinity zinc uptake transporter, the peroxide stress-related alkyl hydroperoxide reductase, isocitrate lyase, and the cell surface protein A.

Detection and Fate of Bacillus anthracis (Sterne) Vegetative Cells and Spores Added to Bulk Tank Milk†

2003 ◽  
Vol 66 (12) ◽  
pp. 2349-2354 ◽  
Author(s):  
MICHAEL L. PERDUE ◽  
JEFF KARNS ◽  
JIM HIGGINS ◽  
JO ANN VAN KESSEL
Keyword(s):  
Bacillus Anthracis ◽  
Protective Antigen ◽  
Lethal Factor ◽  
Raw Milk ◽  
Molecular Data ◽  
Molecular Techniques ◽  
Nucleotide Sequence Analysis ◽  
Vegetative Cells ◽  
Bulk Tank Milk ◽  
Bulk Tank

A preparation of Bacillus anthracis (Sterne strain) spores was used to evaluate commercially available reagents and portable equipment for detecting anthrax contamination by using real-time PCR and was used to assess the fate of spores added directly to bulk tank milk. The Ruggedized Advanced Pathogen Identification Device (RAPID) was employed to detect spores in raw milk down to a concentration of 2,500 spores per ml. Commercially available primers and probes developed to detect either the protective antigen gene or the lethal factor gene both provided easily read positive signals with the RAPID following extraction from milk with a commercially available DNA extraction kit. Nucleotide sequence analysis of the vrrA gene with the use of DNA extracted from spiked milk provided molecular data that readily identified the spores as B. anthracis with a 100% BLAST match to the Sterne and Ames strains and easily distinguished them from B. cereus. Physical-fate and thermal-stability studies demonstrated that spores and vegetative cells have a strong affinity for the cream fraction of whole milk. A single treatment at standard pasteurization temperatures, while 100% lethal to vegetative cells, had no effect on spore viability even 14 days after the treatment. Twenty-four hours after the first treatment, a second treatment at 72°C for 15 s reduced the viability of the population by ca. 99% but still did not kill all of the spores. From these studies, we conclude that standard pasteurization techniques for milk would have little effect on the viability of B. anthracis spores and that raw or pasteurized milk poses no obstacles to the rapid detection of the spores by molecular techniques.

scholarly journals Studies on the Production of Fungal Peroxidases inAspergillus niger

2000 ◽  
Vol 66 (7) ◽  
pp. 3016-3023 ◽  
Author(s):  
Ana Conesa ◽  
Cees A. M. J. J. van den Hondel ◽  
Peter J. Punt
Keyword(s):  
Lignin Peroxidase ◽  
Manganese Peroxidase ◽  
Culture Medium ◽  
Specific Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Limiting Factors ◽  
Efficient Production ◽  
Mrna Levels ◽  
Extracellular Medium

ABSTRACT To get insight into the limiting factors existing for the efficient production of fungal peroxidase in filamentous fungi, the expression of the Phanerochaete chrysosporium lignin peroxidase H8 (lipA) and manganese peroxidase (MnP) H4 (mnp1) genes in Aspergillus niger has been studied. For this purpose, a protease-deficient A. niger strain and different expression cassettes have been used. Northern blotting experiments indicated high steady-state mRNA levels for the recombinant genes. Manganese peroxidase was secreted into the culture medium as an active protein. The recombinant protein showed specific activity and a spectrum profile similar to those of the native enzyme, was correctly processed at its N terminus, and had a slightly lower mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Recombinant MnP production could be increased up to 100 mg/liter upon hemoglobin supplementation of the culture medium. Lignin peroxidase was also secreted into the extracellular medium, although the protein was not active, presumably due to incorrect processing of the secreted enzyme. Expression of the lipA and mnp1 genes fused to the A. niger glucoamylase gene did not result in improved production yields.

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