BACKGROUND Mucoviscosity-associated gene A (magA) is proposed to play a decisive role in the pathogenesis of liver abscesses due to Klebsiella pneumoniae. Although some investigators consider MagA to be a putative O-antigen ligase, it is also reportedly associated with the K1 antigen. METHODS Using magA-positive serotype K1 K. pneumoniae STL43 isolated from a patient with liver abscess, we co...

Bacterial genes involved in the biomineralization of magnetic nanoparticles in magnetotactic bacteria have recently been proposed as reporters for magnetic resonance imaging (MRI). In such systems, the expression of the bacterial genes in mammalian cells purportedly leads to greater concentrations of intracellular iron or the biomineralization of iron oxides, thus leading to an enhancement in r...

Magnetic resonance imaging (MRI) is routinely used to obtain anatomical images that have greatly advanced biomedical research and clinical health care today, but the full potential of MRI in providing functional, physiological, and molecular information is only beginning to emerge. In this work, we sought to provide a gene expression marker for MRI based on bacterial magnetosomes, tiny magnets ...

Mucoviscosity-associated gene A (magA) of Klebsiella pneumoniae contributes to K1 capsular polysaccharide (CPS) biosynthesis. Based on sequence homology and gene alignment, the magA gene has been predicted to encode a Wzy-type CPS polymerase. Sequence alignment with the Wzy_C and RfaL protein families (which catalyze CPS or lipopolysaccharide (LPS) biosynthesis) and topological analysis has sug...

Legionella pneumophila displays a biphasic developmental cycle in which replicating forms (RFs) differentiate postexponentially into highly infectious, cyst-like mature intracellular forms (MIFs). Using comparative protein profile analyses (MIFs versus RFs), we identified a 20-kDa protein, previously annotated as "Mip-like" protein, that was enriched in MIFs. However, this 20-kDa protein shared...

Magnetospirillum sp. AMB-l is a freshwater magnetic bacterium which synthesizes intracellular particles of magnetite (Fe304). A genomic DNA fragment required for synthesis of magnetic particles, was previously isolated from a non-magnetic transposon Tn5 mutant. We have determined the complete nucleotide sequence of this fragment. The 2975 bp region contains two putative open reading frames (ORF...

BACKGROUND The association of the magA gene with the hypermucoviscosity phenotype relevant to the pathogenesis of Klebsiella pneumoniae liver abscess has been reported in Taiwan. Similarly, the rmpA gene, known as a positive regulator of extracapsular polysaccharide synthesis that confers a mucoid phenotype, may be another candidate gene causing hypermucoviscosity. However, the association of r...

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Primary Klebsiella pneumoniae liver abscess complicated with metastatic meningitis or endophthalmitis is a globally emerging infectious disease. Its pathogenic mechanism remains unclear. The bacterial virulence factors were explored by comparing clinical isolates. Differences in mucoviscosity were observed between strains that caused primary liver abscess (invasive) and those that did not (noni...

The relationship of mucoviscosity-associated (magA) and/or regulator of mucoid phenotype (rmpA) genes to the Klebsiella pneumoniae hypermucoviscosity (HMV) phenotype has been reported. We previously demonstrated that rmpA+ K. pneumoniae can cause serious disease in African green monkeys and isolated rmpA+ and magA+ HMV K. pneumoniae from other species of non-human primates. To rapidly screen Af...