Identification of a Hemin Utilization Protein of
            <i>Moraxella catarrhalis</i>
            (HumA)

Furano, Kristin; Campagnari, Anthony A.

doi:10.1128/iai.72.11.6426-6432.2004

Cited by 16 publications

(13 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…HumA, a 91.2-kDa OMP, originally described from M. catarrhalis isolate 7169, was found to bind directly to heme, and growth of a humA-deficient mutant was found to be impaired when heme was used as the sole iron source. Further, expression of the HumA protein was increased when the bacterium was grown in the presence of heme (46).…”

Section: Iron Acquisitionmentioning

confidence: 96%

“…Lactoferrin is the primary carrier of iron on mucosal surfaces, whereas transferrin is the most important iron carrier in serum, and the sequestration of iron is an important line of defense against pathogenic bacteria (119). The acquisition of iron by M. catarrhalis is mediated by several surface- exposed iron-binding proteins: two lactoferrin-binding proteins (LbpA and LbpB) (35), two transferrin-binding proteins (TbpA and TbpB) (154), CopB (4), the heme utilization protein (HumA), (46), and the M. catarrhalis hemoglobin utilization protein (MhuA) (47). M. catarrhalis strain ATCC 25240 was found to be able to utilize both human transferrin and lactoferrin as iron sources.…”

Section: Iron Acquisitionmentioning

confidence: 99%

See 1 more Smart Citation

Molecular Aspects ofMoraxella catarrhalisPathogenesis

Vries

Bootsma

Hays

et al. 2009

Microbiol Mol Biol Rev

View full text Add to dashboard Cite

SUMMARY In recent years, Moraxella catarrhalis has established its position as an important human mucosal pathogen, no longer being regarded as just a commensal bacterium. Further, current research in the field has led to a better understanding of the molecular mechanisms involved in M. catarrhalis pathogenesis, including mechanisms associated with cellular adherence, target cell invasion, modulation of the host's immune response, and metabolism. Additionally, in order to be successful in the host, M. catarrhalis has to be able to interact and compete with the commensal flora and overcome stressful environmental conditions, such as nutrient limitation. In this review, we provide a timely overview of the current understanding of the molecular mechanisms associated with M. catarrhalis virulence and pathogenesis.

show abstract

Section: Iron Acquisitionmentioning

confidence: 96%

Section: Iron Acquisitionmentioning

confidence: 99%

Molecular Aspects ofMoraxella catarrhalisPathogenesis

Vries

Bootsma

Hays

et al. 2009

Microbiol Mol Biol Rev

View full text Add to dashboard Cite

show abstract

“…Iron is a key nutrient that is functionally involved as a cofactor in various metabolic processes and is essential for both M. catarrhalis and its human host (56). The RH4 genome contains genes encoding components of many iron acquisition and transport systems (see Table S8 in the supplemental material), including all of the following M. catarrhalis proteins previously described as proteins involved in this process: lactoferrin binding proteins A and B (17), transferrin binding proteins A and B (74), heme utilization protein (25), M. catarrhalis hemoglobin utilization protein (26), CopB (1), and the main regulator of iron-responsive genes, Fur (24). In addition, iron may be acquired through degradation of heme, which is catalyzed by a heme oxygenase.…”

Section: Central Metabolic Pathwaysmentioning

confidence: 99%

Genome Analysis of Moraxella catarrhalis Strain RH4, a Human Respiratory Tract Pathogen

et al. 2010

View full text Add to dashboard Cite

Moraxella catarrhalis is an emerging human-restricted respiratory tract pathogen that is a common cause of childhood otitis media and exacerbations of chronic obstructive pulmonary disease in adults. Here, we report the first completely assembled and annotated genome sequence of an isolate of M. catarrhalis, strain RH4, which originally was isolated from blood of an infected patient. The RH4 genome consists of 1,863,286 nucleotides that form 1,886 protein-encoding genes. Comparison of the RH4 genome to the ATCC 43617 contigs demonstrated that the gene content of both strains is highly conserved. In silico phylogenetic analyses based on both 16S rRNA and multilocus sequence typing revealed that RH4 belongs to the seroresistant lineage. We were able to identify almost the entire repertoire of known M. catarrhalis virulence factors and mapped the members of the biosynthetic pathways for lipooligosaccharide, peptidoglycan, and type IV pili. Reconstruction of the central metabolic pathways suggested that RH4 relies on fatty acid and acetate metabolism, as the genes encoding the enzymes required for the glyoxylate pathway, the tricarboxylic acid cycle, the gluconeogenic pathway, the nonoxidative branch of the pentose phosphate pathway, the beta-oxidation pathway of fatty acids, and acetate metabolism were present. Moreover, pathways important for survival under challenging in vivo conditions, such as the iron-acquisition pathways, nitrogen metabolism, and oxidative stress responses, were identified. Finally, we showed by microarray expression profiling that ϳ88% of the predicted coding sequences are transcribed under in vitro conditions. Overall, these results provide a foundation for future research into the mechanisms of M. catarrhalis pathogenesis and vaccine development.Moraxella catarrhalis is an emerging human-restricted unencapsulated Gram-negative mucosal pathogen. Long considered to be a commensal of the upper respiratory tract, this bacterium has now firmly been established to be an etiological cause of otitis media (OM) and exacerbations of chronic obstructive pulmonary disease (COPD). It is the third most common cause of childhood OM after Haemophilus influenzae and Streptococcus pneumoniae (37, 64), and it is responsible for up to 20% of the cases (64, 65). Further, M. catarrhalis is the second most common cause of exacerbations of COPD after H. influenzae; it is responsible for 10 to 15% of the exacerbations and annually causes 2 to 4 million episodes in the United States (47, 60). Antibiotics are widely used for treatment of OM, but the high prevalence of this disease and the increasing incidence of antibiotic-resistant strains mean that multivalent vaccines, preferably vaccines with protective antigens for all three causative bacterial agents, must be developed (46).M. catarrhalis is able to colonize the mucosal surfaces of the middle ear in OM patients and the lower respiratory tract in COPD patients (31,60). Successful colonization of the human host is a complex process which requires the expression ...

show abstract

“…Whilst it is assumed that this pathogen has many mechanisms that are similar to those of other human mucosal pathogens, the only systems that have been reported involve iron acquisition through the use of transferrin, lactoferrin and haem (Campagnari et al, 1994;Furano & Campagnari, 2004;Schryvers et al, 1998;Stojiljkovic et al, 1996). As stated previously, iron is an essential element that is required for growth and metabolism of most bacteria and understanding the strategies of iron uptake for M. catarrhalis will provide important information relating to the ability of this pathogen to colonize and survive on host tissues.…”

Section: Discussionmentioning

confidence: 99%