The cell-envelope of Mycobacterium tuberculosis plays a key role in bacterial virulence and antibiotic resistance. Little is known about the molecular mechanisms of regulation of cell-envelope formation. Here, we elucidate functional and structural properties of RNase AS, which modulates M. tuberculosis cell-envelope properties and strongly impacts bacterial virulence in vivo. The structure of ...

The populations of pathogens in individual hosts have many of the characteristics of multicellular organisms, or individuals. These populations go through a life cycle within a host and they reproduce by founding daughter populations in new hosts. Natural selection shapes the life history characteristics of pathogen populations--life expectancy, trade-offs in the allocation of resources between...

Heydrick, Fred P. (Fort Detrick, Frederick, Md.), Ralph F. Wachter, and Henry J. Hearn, Jr. Host influence on the characteristics of Venezuelan equine encephalomyelitis virus. J. Bacteriol. 91:2343-2348. 1966.-Alterations in plaque size, virulence, and lipid content of Venezuelan equine encephalomyelitis (VEE) virus were examined for possible interrelationships among these properties during 10 ...

Legionella pneumophila is a gram-negative bacterial species that is ubiquitous in almost any aqueous environment. It is the agent of Legionnaires' disease, an acute and often under-reported form of pneumonia. In mammals, L. pneumophila replicates inside macrophages within a modified vacuole. Many protein regulators have been identified that control virulence-related properties, including RpoS, ...

Microbes that protect their hosts from pathogens are widespread in nature and are attractive disease control agents. Given that pathogen adaptation to barriers against infection can drive changes in pathogen virulence, 'defensive microbes' may shape disease severity. Here we show that co-evolving a microbe with host-protective properties (Enterococcus faecalis) and a pathogen (Staphylococcus au...

Bacterial virulence proteins, which have been classified on structure of virulence, causes several diseases. For instance, Adhesins play an important role in the host cells. They are inserted DNA sequences for a variety of virulence properties. Several important methods conducted for the prediction of bacterial virulence proteins for finding new drugs or vaccines. In this study, we propose a me...

After isolating three clones of Trypanosoma cruzi (Bolivia), we first characterized them according to parasitaemia, pleomorphism and virulence, and then histopathologically. The study's interest lies on the hypothesis that clonal evolution of T. cruzi has a major impact on biologically relevant properties of this parasite. Data obtained from the studies of parasitaemia, pleomorphism and virulen...

background and aims: the aim of this study was to determine the virulence and antibiotic resistance properties of streptococcus agalactiae (s. agalactiae) and streptococcus uberis (s. uberis) isolated from the ruminant’s sub-clinical mastitic milk in iran. materials and methods: positive samples in the cmt test were cultured and s. agalactiae and s. uberis have been identified using biochemical...

An unanswered question concerning prevalence and disease severity of Chlamydia trachomatis genital infection is whether more prevalent strains or strains more likely to cause serious disease complications are causally associated with specific virulence attributes. The major method for distinguishing chlamydial strains is based on differences in the major outer membrane protein (MOMP). A subset ...

background and objectives: enteropathogenic escherichia coli (epec) divided into two groups typical and atypical (aspect). the main virulence genes are located in a pathogenicity island called lee ( locus of enterocyte effacement ). lee frequently inserted in trna genes of selc , pheu and phev in the bacterial chromosome. tepec and aepec strains have some differences in their pathogenicity. the...