Clostridium perfringens causes necrotic enteritis in chickens, and alpha-toxin has been suggested to be a key virulence determinant. Analysis of the alpha-toxin of 25 chicken-derived C. perfringens strains demonstrated high homology to mammal-derived strains rather than to the only avian-derived C. perfringens alpha-toxin sequence reported previously.

The virulence of the uropathogenic E. coli strain 536 (O6:K15:H31) which produces the S-fimbrial adhesin (Sfa+), is serum-resistant (Sre+) and hemolytic (Hly+) and its derivatives were assessed in five different animal models. Cloned hemolysin (hly) determinants from the chromosomes of O6, O18 and O75 E. coli strains and from the plasmid pHly152 were introduced into the spontaneous Sfa-, Sre-, ...

Background Janibacter melonis and other member of this genus are known to cause bacteremia and serious clinical comorbidities, but there is no study reporting about pathogenicity attributes of J. melonis. Janibacter terrae is known to cause lethal infection. Reporting the genome of J. melonis CD11-4 and comparative genomics with other members of genus has provided some novel insights that can e...

The staphylococcal accessory regulator (encoded by sarA) is an important global regulator of virulence factor biosynthesis in Staphylococcus aureus. To further characterize its role in virulence determinant production, an sarA knockout mutant was created by insertion of a kanamycin antibiotic resistance cassette into the sarA gene. N-terminal sequencing of exoproteins down-regulated by sarA ide...

We report here the 3.8-Mb genome sequence of Kocuria polaris strain CD08_4, an isolate from the duodenal mucosa of a celiac disease patient. The genome consists of specific virulence determinant genes, antibiotic resistance genes, genes for coping with oxidative stress, and genes responsible for iron acquisition and metabolism, suggestive of its pathogenic attributes.

Some Newcastle disease virus (NDV) variants isolated from pigeons (pigeon paramyxovirus type 1; PPMV-1) do not show their full virulence potential for domestic chickens but may become virulent upon spread in these animals. In this study we examined the molecular changes responsible for this gain of virulence by passaging a low-pathogenic PPMV-1 isolate in chickens. Complete genome sequencing of...

we study the set of all determinants of adjacency matrices of graphs with a given number of vertices. using brendan mckay's data base of small graphs, determinants of graphs with at most $9$ vertices are computed so that the number of non-isomorphic graphs with given vertices whose determinants are all equal to a number is exhibited in a table. using an idea of m. newman, it is proved that if $...

The bacterial plant pathogen Pseudomonas syringae pv. tomato DC3000 (DC3000) causes disease in Arabidopsis thaliana and tomato plants, and it elicits the hypersensitive response in nonhost plants such as Nicotiana tabacum and Nicotiana benthamiana. While these events chiefly depend upon the type III protein secretion system and the effector proteins that this system translocates into plant cell...

Toxoplasma gondii is an opportunistic intracellular parasite which induces a highly strong type 1 cytokine response. The present study focuses on defining the factors influencing the outcome of infection with tachyzoites of the type I, highly lethal RH strain, relative to the type II, low virulence strain ME49. Infection with the RH strain led to widespread parasite dissemination and rapid deat...