scholarly journals The Flat-Ribbon Configuration of the Periplasmic Flagella of Borrelia burgdorferi and Its Relationship to Motility and Morphology

2008 ◽  
Vol 191 (2) ◽  
pp. 600-607 ◽  
Author(s):  
Nyles W. Charon ◽  
Stuart F. Goldstein ◽  
Michael Marko ◽  
Chyongere Hsieh ◽  
Linda L. Gebhardt ◽  
...  
Keyword(s):  
Borrelia Burgdorferi ◽  
Direct Contact ◽  
Periplasmic Space ◽  
Membrane Blebs ◽  
Wave Morphology ◽  
Electron Cryotomography ◽  
Periplasmic Flagella ◽  
Conventional Electron Microscopy

ABSTRACT Electron cryotomography was used to analyze the structure of the Lyme disease spirochete, Borrelia burgdorferi. This methodology offers a new means for studying the native architecture of bacteria by eliminating the chemical fixing, dehydration, and staining steps of conventional electron microscopy. Using electron cryotomography, we noted that membrane blebs formed at the ends of the cells. These blebs may be precursors to vesicles that are released from cells grown in vivo and in vitro. We found that the periplasmic space of B. burgdorferi was quite narrow (16.0 nm) compared to those of Escherichia coli and Pseudomonas aeruginosa. However, in the vicinity of the periplasmic flagella, this space was considerably wider (42.3 nm). In contrast to previous results, the periplasmic flagella did not form a bundle but rather formed a tight-fitting ribbon that wraps around the protoplasmic cell cylinder in a right-handed sense. We show how the ribbon configuration of the assembled periplasmic flagella is more advantageous than a bundle for both swimming and forming the flat-wave morphology. Previous results indicate that B. burgdorferi motility is dependent on the rotation of the periplasmic flagella in generating backward-moving waves along the length of the cell. This swimming requires that the rotation of the flagella exerts force on the cell cylinder. Accordingly, a ribbon is more beneficial than a bundle, as this configuration allows each periplasmic flagellum to have direct contact with the cell cylinder in order to exert that force, and it minimizes interference between the rotating filaments.

scholarly journals Use of an Endogenous Plasmid Locus for Stable intransComplementation in Borrelia burgdorferi

2014 ◽  
Vol 81 (3) ◽  
pp. 1038-1046 ◽  
Author(s):  
Irene N. Kasumba ◽  
Aaron Bestor ◽  
Kit Tilly ◽  
Patricia A. Rosa
Keyword(s):  
Borrelia Burgdorferi ◽  
Shuttle Vector ◽  
Targeted Mutagenesis ◽  
Multiple Cloning Site ◽  
Stable Gene ◽  
Content Type ◽  
Shuttle Vectors ◽  
Stable Maintenance

ABSTRACTTargeted mutagenesis and complementation are important tools for studying genes of unknown function in the Lyme disease spirocheteBorrelia burgdorferi. A standard method of complementation is reintroduction of a wild-type copy of the targeted gene on a shuttle vector. However, shuttle vectors are present at higher copy numbers thanB. burgdorferiplasmids and are potentially unstable in the absence of selection, thereby complicating analyses in the mouse-tick infectious cycle.B. burgdorferihas over 20 plasmids, with some, such as linear plasmid 25 (lp25), carrying genes required by the spirochetein vivobut relatively unstable duringin vitrocultivation. We propose that complementation on an endogenous plasmid such as lp25 would overcome the copy number andin vivostability issues of shuttle vectors. In addition, insertion of a selectable marker on lp25 could ensure its stable maintenance by spirochetes in culture. Here, we describe the construction of a multipurpose allelic-exchange vector containing a multiple-cloning site and either of two selectable markers. This suicide vector directs insertion of the complementing gene into thebbe02locus, a site on lp25 that was previously shown to be nonessential during bothin vitroandin vivogrowth. We demonstrate the functional utility of this strategy by restoring infectivity to anospCmutant through complementation at this site on lp25 and stable maintenance of theospCgene throughout mouse infection. We conclude that this represents a convenient and widely applicable method for stable gene complementation inB. burgdorferi.

scholarly journals In vitro experiments of cerebral blood flow during aspiration thrombectomy: potential effects on cerebral perfusion pressure and collateral flow

2015 ◽  
Vol 8 (9) ◽  
pp. 969-972 ◽  
Author(s):  
Frank Lally ◽  
Mitra Soorani ◽  
Timothy Woo ◽  
Sanjeev Nayak ◽  
Changez Jadun ◽  
...  
Keyword(s):  
Direct Contact ◽  
Flow Direction ◽  
Flow Characteristics ◽  
Collateral Flow ◽  
In Vitro Experiments ◽  
Aspiration Thrombectomy ◽  
Flow Solver ◽  
Catheter Tip

BackgroundMechanical thrombectomy with stent retriever devices is associated with significantly better outcomes than thrombolysis alone in the treatment of acute ischemic stroke. Thrombus aspiration achieves high patency rates, but clinical outcomes are variable. The aim of this study was to examine the effect of different suction conditions on perfusate flow during aspiration thrombectomy.MethodsA computational fluid dynamics model of an aspiration device within a patent and occluded blood vessel was used to simulate flow characteristics using fluid flow solver software. A physical particulate flow model of a patent vessel and a vessel occluded by thrombus was then used to visualize flow direction and measure flow rates with the aspiration catheter placed 1–10 mm proximal of the thrombus, and recorded on video.ResultsThe mathematical model predicted that, in a patent vessel, perfusate is drawn from upstream of the catheter tip while, in an occluded system, perfusate is drawn from the vessel proximal to the device tip with no traction on the occlusion distal of the tip. The in vitro experiments confirmed the predictions of this model. In the occluded vessel aspiration had no effect on the thrombus unless the tip of the catheter was in direct contact with the thrombus.ConclusionsThese experiments suggest that aspiration is only effective if the catheter tip is in direct contact with the thrombus. If the catheter tip is not in contact with the thrombus, aspirate is drawn from the vessels proximal of the occlusion. This could affect collateral flow in vivo.

scholarly journals Reduced Immune Response to Borrelia burgdorferi in the Absence of γδ T Cells

2011 ◽  
Vol 79 (10) ◽  
pp. 3940-3946 ◽  
Author(s):  
Cuixia Shi ◽  
Bikash Sahay ◽  
Jennifer Q. Russell ◽  
Karen A. Fortner ◽  
Nicholas Hardin ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cells ◽  
Borrelia Burgdorferi ◽  
Adaptive Immune Response ◽  
Γδ T Cells ◽  
Content Type ◽  
Adaptive Immune ◽  
Cytokines And Chemokines

ABSTRACTLittle is known regarding the function of γδ T cells, although they accumulate at sites of inflammation in infections and autoimmune disorders. We previously observed that γδ T cellsin vitroare activated byBorrelia burgdorferiin a TLR2-dependent manner. We now observe that the activated γδ T cells can in turn stimulate dendritic cellsin vitroto produce cytokines and chemokines that are important for the adaptive immune response. This suggested thatin vivoγδ T cells may assist in activating the adaptive immune response. We examined this possibilityin vivoand observed that γδ T cells are activated and expand in number duringBorreliainfection, and this was reduced in the absence of TLR2. Furthermore, in the absence of γδ T cells, there was a significantly blunted response of adaptive immunity, as reflected in reduced expansion of T and B cells and reduced serum levels of anti-Borreliaantibodies, cytokines, and chemokines. This paralleled a greaterBorreliaburden in γδ-deficient mice as well as more cardiac inflammation. These findings are consistent with a model of γδ T cells functioning to promote the adaptive immune response during infection.

scholarly journals Role of the BBA64 Locus of Borrelia burgdorferi in Early Stages of Infectivity in a Murine Model of Lyme Disease

2007 ◽  
Vol 76 (1) ◽  
pp. 391-402 ◽  
Author(s):  
Mahulena Maruskova ◽  
M. Dolores Esteve-Gassent ◽  
Valerie L. Sexton ◽  
J. Seshu
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Immunoblot Analysis ◽  
Open Reading Frames ◽  
Mammalian Host ◽  
Environmental Signals ◽  
Significant Difference ◽  
Linear Plasmid 54

ABSTRACT Borrelia burgdorferi, the causative agent of Lyme disease, undergoes rapid adaptive gene expression in response to environmental signals encountered during different stages of its life cycle in the arthropod vector or the mammalian host. Among all the plasmid-encoded genes of B. burgdorferi, several linear plasmid 54 (lp54)-encoded open reading frames (ORFs) exhibit the greatest differential expression in response to mammalian host-specific temperature, pH, and other uncharacterized signals. These ORFs include members of the paralogous gene family 54 (pgf 54), such as BBA64, BBA65, and BBA66, present on lp54. In an attempt to correlate transcriptional up-regulation of these pgf 54 members to their role in infectivity, we inactivated BBA64 and characterized the phenotype of this mutant both in vitro and in vivo. There were no major differences in the protein profiles between the BBA64 mutant and the control strains, while immunoblot analysis indicated that inactivation of BBA64 resulted in increased levels of BBA65. Moreover, there was no significant difference in the ability of the BBA64 mutant to infect C3H/HeN mice compared to that of its parental or complemented control strains as determined by culturing of viable spirochetes from infected tissues. However, enumeration of spirochetes using quantitative real-time PCR revealed tissue-specific differences, suggesting a minimal role for BBA64 in the survival of B. burgdorferi in select tissues. Infectivity analysis of the BBA64 mutant suggests that B. burgdorferi may utilize multiple determinants to establish infection in mammalian hosts.

scholarly journals Natural chromatin is heterogeneous and self-associates in vitro

2018 ◽  
Vol 29 (13) ◽  
pp. 1652-1663 ◽  
Author(s):  
Shujun Cai ◽  
Yajiao Song ◽  
Chen Chen ◽  
Jian Shi ◽  
Lu Gan
Keyword(s):  
Divalent Cations ◽  
Large Mass ◽  
Higher Order ◽  
Linker Histone ◽  
Order Structure ◽  
Face To Face ◽  
Chromatin Packing ◽  
Electron Cryotomography

The 30-nm fiber is commonly formed by oligonucleosome arrays in vitro but rarely found inside cells. To determine how chromatin higher-order structure is controlled, we used electron cryotomography (cryo-ET) to study the undigested natural chromatin released from two single-celled organisms in which 30-nm fibers have not been observed in vivo: picoplankton and yeast. In the presence of divalent cations, most of the chromatin from both organisms is condensed into a large mass in vitro. Rare irregular 30-nm fibers, some of which include face-to-face nucleosome interactions, do form at the periphery of this mass. In the absence of divalent cations, picoplankton chromatin decondenses into open zigzags. By contrast, yeast chromatin mostly remains condensed, with very few open motifs. Yeast chromatin packing is largely unchanged in the absence of linker histone and mildly decondensed when histones are more acetylated. Natural chromatin is therefore generally nonpermissive of regular motifs, even at the level of oligonucleosomes.

scholarly journals Active and Passive Immunity against Borrelia burgdorferi Decorin Binding Protein A (DbpA) Protects against Infection

1998 ◽  
Vol 66 (5) ◽  
pp. 2143-2153 ◽  
Author(s):  
Mark S. Hanson ◽  
David R. Cassatt ◽  
Betty P. Guo ◽  
Nita K. Patel ◽  
Michael P. McCarthy ◽  
...  
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Low Dose ◽  
Early Stage ◽  
Protein A ◽  
Sensu Stricto ◽  
Passive Immunity ◽  
In Vitro Growth

ABSTRACT Borrelia burgdorferi, the spirochete that causes Lyme disease, binds decorin, a collagen-associated extracellular matrix proteoglycan found in the skin (the site of entry for the spirochete) and in many other tissues. Two borrelial adhesins that recognize this proteoglycan, decorin binding proteins A and B (DbpA and DbpB, respectively), have recently been identified. Infection of mice by low-dose B. burgdorferi challenge elicited antibodies against DbpA and DbpB that were sustained at high levels, suggesting that these antigens are expressed in vivo. Scanning immunoelectron microscopy showed that DbpA was surface accessible on intact borreliae. Passive administration of DbpA antiserum protected mice from infection following challenge with heterologous B. burgdorferi sensu stricto isolates, even when serum administration was delayed for up to 4 days after challenge. DbpA is the first antigen target identified that is capable of mediating immune resolution of early, localizedB. burgdorferi infections. DbpA immunization also protected mice from B. burgdorferi challenge; DbpB immunization was much less effective. DbpA antiserum inhibited in vitro growth of manyB. burgdorferi sensu lato isolates of diverse geographic, phylogenetic, and clinical origins. In combination, these findings support a role for DbpA in the immunoprophylaxis of Lyme disease and suggest that DbpA vaccines have the potential to eliminate early-stageB. burgdorferi infections.

scholarly journals Antitumor in vitro and in vivo effects of lipid composites of cisplatin and ferromagnetic nanoparticles capsulated by carbonic coating

2010 ◽  
Vol 9 (1) ◽  
pp. 9-16 ◽  
Author(s):  
S. A. Antipov ◽  
T. A. Feduschak ◽  
O. V. Kokorev ◽  
Ye. A. Gereng ◽  
G. Ts. Dambayev ◽  
...  
Keyword(s):  
Direct Contact ◽  
Malignant Cell ◽  
Cytostatic Drug ◽  
Ferromagnetic Nanoparticles ◽  
Biotechnological Approach ◽  
Adenocarcinoma Cells ◽  
In Vivo Effects ◽  
Stimulation Of

An investigation of in vitro and in vivo reaction of adenocarcinoma cells in conditions of direct contact with composites designed in a base of phospholipid concentrate, cisplatin and nanoparticles (diameter less than 10 nm) of iron capsulated by carbonic coating was the aim of paper. Their antitumor effect has been established to be conditioned by direct cytotoxic relatively elective action on malignant cell and, on the other hand, by stimulation of tumor node fibrosis. Proposed biotechnological approach that used low doses of cytostatic drug (1/10 LD50) and nanoferromagnetic particles (2 mg/kg) may be useful to design magnetocontrollable regimes for regional immuno(bio)therapy of cancer and its metastases.

scholarly journals Bactericidal Activity of Octenidine to Various Genospecies of Borrelia burgdorferi, Sensu Lato Spirochetes in Vitro and in Vivo

2017 ◽  
Vol 66 (2) ◽  
pp. 259-263 ◽  
Author(s):  
Stanisława Tylewska-Wierzbanowska ◽  
Urszula Roguska ◽  
Grażyna Lewandowska ◽  
Tomasz Chmielewski
Keyword(s):  
Borrelia Burgdorferi ◽  
Bactericidal Activity ◽  
Reliable Method ◽  
Bactericidal Effect ◽  
Sensu Stricto ◽  
Borrelia Burgdorferi Sensu Lato ◽  
Bactericidal Action ◽  
Speed Up

The aim of our studies was to invent a reliable method for detection of bactericidal activity of disinfectants against Borrelia burgdorferi in suspension (in vitro) and in cell line cultures (in vivo). In the suspension method, 0.01 % octenidine at 20°C and 35°C was bactericidal to Borrelia afzeli; Borrelia garini, B. burgdorferi sensu stricto after 5 minutes treatment. Increase of the temperature to 35°C speed up the bactericidal effect to 1 minute. The bactericidal action of octenidine towards B. burgdorferi spirochetes growing in fibroblasts was less effective and needed a longer time to kill them than in the suspension.

scholarly journals Monkeypox Transmission, Need and Treatment of Humans with an Antiviral Drug

2017 ◽  
Vol 4 (2) ◽  
pp. 77-79
Author(s):  
Chanda Jabeen ◽  
Gulshan Umbreen
Keyword(s):  
Direct Contact ◽  
Infected Animal ◽  
Antiviral Drug ◽  
Zoonotic Disease ◽  
Genetic Changes ◽  
The Family

Monkeypox is a viral zoonotic disease belongs to the family Poxviridae and Orthopoxvirus genus. Transmission of monkey pox is through direct contact with infected animal and blood. Human to human transmission occur through respiratory route but previously so many studies are conducted to prove that monkey pox viruse was not transmitted through the respiratory route both in animals and humans. But now monkey pox is able to survive in humans due to genetic changes and human to human transmission is possible. Because it can be used as bioweapon, So there is a great need of having an antiviral drug which is effective against monkey pox virus.ST 246 proved effective in vivo and in vitro in infected animals and trials done safely on non-infected humans but no data is available about the effectiveness of ST 246 on monkey pox or Orthopox infected human treated with ST 246.Int. J. Soc. Sc. Manage. Vol. 4, Issue-2: 77-79 

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