Geodesics around Weyl-Bach's Ring Solution

We explore some of the gravitational features of a uniform ring both in the Newtonian potential theory and in General Relativity. We use a spacetime associated to a Weyl static solution of the vacuum Einstein's equations with ring like singularity. The Newtonian motion for a test particle in the gravitational field of the ring is studied and compared with the corresponding geodesic motion in the given spacetime. We have found a relativistic peculiar attraction: free falling particle geodesics are lead to the inner rim but never hit the ring.Comment: 8 figures, 14 pages. LaTeX w/ subfigure, graphic

The complete genome sequence of Corynebacterium pseudotuberculosis FRC41 isolated from a 12-year-old girl with necrotizing lymphadenitis reveals insights into gene-regulatory networks contributing to virulence

Trost E, Ott L, Schneider J, et al. The complete genome sequence of Corynebacterium pseudotuberculosis FRC41 isolated from a 12-year-old girl with necrotizing lymphadenitis reveals insights into gene-regulatory networks contributing to virulence. BMC Genomics. 2010;11(1): 728

Evidence for Reductive Genome Evolution and Lateral Acquisition of Virulence Functions in Two Corynebacterium pseudotuberculosis Strains

Ruiz JC, D'Afonseca V, Silva A, et al. Evidence for Reductive Genome Evolution and Lateral Acquisition of Virulence Functions in Two Corynebacterium pseudotuberculosis Strains. PLoS ONE. 2011;6(4): e18551.Background: Corynebacterium pseudotuberculosis, a Gram-positive, facultative intracellular pathogen, is the etiologic agent of the disease known as caseous lymphadenitis (CL). CL mainly affects small ruminants, such as goats and sheep; it also causes infections in humans, though rarely. This species is distributed worldwide, but it has the most serious economic impact in Oceania, Africa and South America. Although C. pseudotuberculosis causes major health and productivity problems for livestock, little is known about the molecular basis of its pathogenicity. Methodology and Findings: We characterized two C. pseudotuberculosis genomes (Cp1002, isolated from goats; and CpC231, isolated from sheep). Analysis of the predicted genomes showed high similarity in genomic architecture, gene content and genetic order. When C. pseudotuberculosis was compared with other Corynebacterium species, it became evident that this pathogenic species has lost numerous genes, resulting in one of the smallest genomes in the genus. Other differences that could be part of the adaptation to pathogenicity include a lower GC content, of about 52%, and a reduced gene repertoire. The C. pseudotuberculosis genome also includes seven putative pathogenicity islands, which contain several classical virulence factors, including genes for fimbrial subunits, adhesion factors, iron uptake and secreted toxins. Additionally, all of the virulence factors in the islands have characteristics that indicate horizontal transfer. Conclusions: These particular genome characteristics of C. pseudotuberculosis, as well as its acquired virulence factors in pathogenicity islands, provide evidence of its lifestyle and of the pathogenicity pathways used by this pathogen in the infection process. All genomes cited in this study are available in the NCBI Genbank database (http://www.ncbi.nlm.nih.gov/genbank/) under accession numbers CP001809 and CP001829

Reannotation of the Corynebacterium diphtheriae NCTC13129 genome as a new approach to studying gene targets connected to virulence and pathogenicity in diphtheria.

Background: The reannotation of genomes already on file is a new approach to discovering new genetic elements and to make the genomes more descriptive and current with relevant features regarding the organism?s lifestyle. Within this approach, the present study aimed to reannotate the genome of the Gram-positive human pathogen Corynebacterium diphtheriae, which causes diphtheria. The deposit of massive amounts of information linked to other species of the genus Corynebacterium has facilitated the updating of the genomic interpretation of this microorganism. Additionally, the emergence of invasive disease by nontoxigenic strains of C. diphtheriae and the reemergence of diphtheria in partially immunized populations have given impetus to new studies in relation to its structural and functional genome. Results: In relation to structural genomics, 23 coding regions (coding sequences) were deleted and 71 new genes were added to the genome annotation. Nevertheless, all the pseudogenes were validated and ten new pseudogenes were created. In relation to functional genomics, about 57% of the genome annotation was updated and became functionally more informative. The product descriptions of 41% (973 proteins) were updated. Among them, 370 that were previously annotated as ?hypothetical proteins,? now have more informative descriptions. With the new annotation, the plasticity of the genome became evident, which shows improvements in the annotation of 13 pathogenicity islands already described in the literature. In addition, the large number of transposases and the presence of structural genes of bacteriophages make their genomic versatility evident. Contrasting with this reality, it also allowed the clarification of some aspects concerned with mechanisms used by C. diphtheriae to stop the invasion of the genome by bacteriophages, mediated by the clustered regularly interspaced short palindromic repeats region. Conclusion: The reannotation of the C. diphtheriae genome provided an improvement in annotation of the C. diphtheriae genome in several aspects, such as virulence characteristics and plasticity events. Moreover, the protocol used here can be extended to various other pathogens in order to improve the genomic information already on file in public databases and to minimize propagating errors. The reannotated archive and updated archive are available at: http://lgcm.icb.ufmg.br/pub/C_diphtheriae_reannotation.embl

Evidence for reductive genome evolution and lateral acquisition of virulence functions in two Corynebacterium pseudotuberculosis strains.

Background: Corynebacterium pseudotuberculosis, a Gram-positive, facultative intracellular pathogen, is the etiologic agent of the disease known as caseous lymphadenitis (CL). CL mainly affects small ruminants, such as goats and sheep; it also causes infections in humans, though rarely. This species is distributed worldwide, but it has the most serious economic impact in Oceania, Africa and South America. Although C. pseudotuberculosis causes major health and productivity problems for livestock, little is known about the molecular basis of its pathogenicity. Methodology and Findings: We characterized two C. pseudotuberculosis genomes (Cp1002, isolated from goats; and CpC231, isolated from sheep). Analysis of the predicted genomes showed high similarity in genomic architecture, gene content and genetic order. When C. pseudotuberculosis was compared with other Corynebacterium species, it became evident that this pathogenic species has lost numerous genes, resulting in one of the smallest genomes in the genus. Other differences that could be part of the adaptation to pathogenicity include a lower GC content, of about 52%, and a reduced gene repertoire. The C. pseudotuberculosis genome also includes seven putative pathogenicity islands, which contain several classical virulence factors, including genes for fimbrial subunits, adhesion factors, iron uptake and secreted toxins. Additionally, all of the virulence factors in the islands have characteristics that indicate horizontal transfer. Conclusions: These particular genome characteristics of C. pseudotuberculosis, as well as its acquired virulence factors in pathogenicity islands, provide evidence of its lifestyle and of the pathogenicity pathways used by this pathogen in the infection process. All genomes cited in this study are available in the NCBI Genbank database (http://www.ncbi.nlm.nih.gov/ genbank/) under accession numbers CP001809 and CP001829.Made available in DSpace on 2018-05-11T00:36:49Z (GMT). No. of bitstreams: 1 journal.pone.0018551.pdf: 394055 bytes, checksum: 9a23eb5b1d44e130bf137337fc894796 (MD5) Previous issue date: 2012-02-08bitstream/item/53621/1/journal.pone.0018551.pd

Evidence for reductive genome evolution and lateral acquisition of virulence functions in two Corynebacterium pseudotuberculosis strains.

Background: Corynebacterium pseudotuberculosis, a Gram-positive, facultative intracellular pathogen, is the etiologic agent of the disease known as caseous lymphadenitis (CL). CL mainly affects small ruminants, such as goats and sheep; it also causes infections in humans, though rarely. This species is distributed worldwide, but it has the most serious economic impact in Oceania, Africa and South America. Although C. pseudotuberculosis causes major health and productivity problems for livestock, little is known about the molecular basis of its pathogenicity. Methodology and Findings: We characterized two C. pseudotuberculosis genomes (Cp1002, isolated from goats; and CpC231, isolated from sheep). Analysis of the predicted genomes showed high similarity in genomic architecture, gene content and genetic order. When C. pseudotuberculosis was compared with other Corynebacterium species, it became evident that this pathogenic species has lost numerous genes, resulting in one of the smallest genomes in the genus. Other differences that could be part of the adaptation to pathogenicity include a lower GC content, of about 52%, and a reduced gene repertoire. The C. pseudotuberculosis genome also includes seven putative pathogenicity islands, which contain several classical virulence factors, including genes for fimbrial subunits, adhesion factors, iron uptake and secreted toxins. Additionally, all of the virulence factors in the islands have characteristics that indicate horizontal transfer. Conclusions: These particular genome characteristics of C. pseudotuberculosis, as well as its acquired virulence factors in pathogenicity islands, provide evidence of its lifestyle and of the pathogenicity pathways used by this pathogen in the infection process. All genomes cited in this study are available in the NCBI Genbank database (http://www.ncbi.nlm.nih.gov/genbank/) under accession numbers CP001809 and CP001829.201

Pangenomic Study of Corynebacterium diphtheriae That Provides Insights into the Genomic Diversity of Pathogenic Isolates from Cases of Classical Diphtheria, Endocarditis, and Pneumonia

Trost E, Blom J, de Castro Soares S, et al. Pangenomic Study of Corynebacterium diphtheriae That Provides Insights into the Genomic Diversity of Pathogenic Isolates from Cases of Classical Diphtheria, Endocarditis, and Pneumonia. Journal of bacteriology. 2012;194(12):3199-3215.Corynebacterium diphtheriae is one of the most prominent human pathogens and the causative agent of the communicable disease diphtheria. The genomes of 12 strains isolated from patients with classical diphtheria, endocarditis, and pneumonia were completely sequenced and annotated. Including the genome of C. diphtheriae NCTC 13129, we herewith present a comprehensive comparative analysis of 13 strains and the first characterization of the pangenome of the species C. diphtheriae. Comparative genomics showed extensive synteny and revealed a core genome consisting of 1,632 conserved genes. The pangenome currently comprises 4,786 protein-coding regions and increases at an average of 65 unique genes per newly sequenced strain. Analysis of prophages carrying the diphtheria toxin gene tox revealed that the toxoid vaccine producer C. diphtheriae Park-Williams no. 8 has been lysogenized by two copies of the omega(tox)(+) phage, whereas C. diphtheriae 31A harbors a hitherto-unknown tox(+) corynephage. DNA binding sites of the tox-controlling regulator DtxR were detected by genome-wide motif searches. Comparative content analysis showed that the DtxR regulons exhibit marked differences due to gene gain, gene loss, partial gene deletion, and DtxR binding site depletion. Most predicted pathogenicity islands of C. diphtheriae revealed characteristics of horizontal gene transfer. The majority of these islands encode subunits of adhesive pili, which can play important roles in adhesion of C. diphtheriae to different host tissues. All sequenced isolates contain at least two pilus gene clusters. It appears that variation in the distributed genome is a common strategy of C. diphtheriae to establish differences in host-pathogen interactions