Bartonella quintana: Difference between revisions
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==Cell structure and metabolism== | ==Cell structure and metabolism== | ||
A number of bacterial pathogens have evolved for accumulating hemin in order to satisfy their iron, proporphyrin ring, or cytcochrome cofactor requirements. However, early studies with B. quintana indicated that iron is the critical component provided by hemin supplements (15). The transport of iron from hemin is a TonB-dependent process that requires the synthesis of a surface-membrane receptor to facilitate the binding of the ligand. Next, a protein in the periplasmic space transports the hemin to the cytoplasmic membrane, and finally a permease brings the molecule into the bacterial cell (16). | |||
In early 1960’s, Vinson first cultured B. quintana in axenic media, either in blood–enriched agar or in broth with amino acids, yeast extract, and fetal bovine serum (2). These microorganisms obtain their source of energy from succinate, pyruvate, and glutamate but unable to use glucose. In addition, bicarbonate is essential for B. quintana as a source of carbon dioxide (1). Because Bartonella spp. are the only bacterial pathogens that engage in hemotrophy (erythrocyte parasitism), all Bartonella species require erythrocytes or hemin supplements in order to grow in vitro. B. quintana has the highest hemin requirement (20 to 40 µg/ml of medium) for a bacterium (15). There is a family of hemin binding proteins (HbpA, HbpB, HbpC, HbpD, and HbpE) that is synthesized by B. quintana and is served as hemin receptors (18). However, the reason for this unique characterization of B. quintana hemin requirement and mechanism is still unclear. Although HbpA plays a role in the ability of B. quintana to acquire hemin from the environment (abiotic or biotic), antibiotics specific for HbpA may inhibit the ligand-receptor interaction (17). Because HbpA is only one of the eight membrane-associated proteins in the organism, hemin binding is not abolished in the presence of anti-HbpA Fab fragments. The exact localization and involvement in iron acquisition of the additional hemin-binding membrane proteins is currently under investigation (18). | |||
Edited by | Pili and specialized extensions of the outer membrane are thought to play an important role in adhesin to nucleated cells. Pili structures in B. henselae, B. quintana, B. tribocorum, and B. alsatica posses type IV pili. Twitching motility and self-aggregation are specific properties typical for this type of pili (19). | ||
Edited by Rani Thamawatankul, student of Rachel Larsen at UCSD. | |||
==Ecology== | ==Ecology== | ||
Revision as of 03:39, 5 June 2007
A Microbial Biorealm page on the genus Bartonella quintana
Classification
Gram-negative rod shape
Higher order taxa
Domain:Bacteria, Phylum: Proteobacteria, Class: Alpha Proteobacteria, Order: Rhizobiales, Family: Bartonellacaea
Edited by Rani Thamawatanakul, student of Rachel Larsen at UCSD.
Genus
Genus species: Bartonella Quintana
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NCBI: Taxonomy |
Edited by Rani Thamawatankul, student of Rachel Larsen at UCSD.
Description and significance
Bartonella quintana was formally classified in the Rickettsiaceae family as the obligately intracellular (cannot reproduce outside the host cell) Rochalimaea quintana (28). The difference between Rickettsia and Rochalimaea was the chemical composition in their genomic structure. Rickettsia species have a low level of guanine and cytosine (28.5 – 33.3 mol%) but Rochalimaea and Bartonella species have a higher level (39.0 – 40.0 mol%). The description of these species has increased by the availability of modern taxonomic methods. Few techniques would include DNA hybridization and 16 rRNA gene sequence comparison (4).
B. quintana as opposed to related species, B. bacilliformis and B. clarrideiae that posses flagella uses a twitching movement caused by fimbriae. B.quintana is a facultative, Gram-negative bacilli belonging to 2 subgroup of proteobacteria. The dimensions of the bacterium is 0.3 – 0,5 m wide and 1-1.7 m long (7). It can be cultured in media containing blood or hemin and in a moist 5-10% carbon dioxide atmosphere at 30C to 37C (5). Because B. quintana is a slow-growing bacterium, primary isolations are available 12 to 14 days after B. quintana has been embedded and incubated in blood agar at 37C. Unfortunately, incubation periods could last as long as 45 days that is necessary for primary isolations (3).
Humans are the reservoir of the bacterium but the mode of transmission comes directly from a human body louse, Pediculus humanus corporis (20). During asymptomatic period, B. quintana is located in the erythrocytes and has been detected in erythroblasts at the bone marrow (12). Also, bacillary angiomatosis infection is caused by B. quintana having an affinity for endothelial cells, leading to angioproliferative lesions (13).
Currently, B. quintana is unique among bacterial pathogens it has reemerged as an opportunistic infectious agent primarily in immunocompromised patients, especially individuals suffering with HIV infection. It also causes a febrile disease among alcoholic individuals and the homeless populations in the cities in United States and Europe called “urban trench fever” (11). B. quintana infections can manifest as bacillary angiomatosis, bacillary peliosis, endocarditis, and chronic bacteremia, which could be life-threatening if these conditions occurred concurrently (7).
Edited by Rani Thamawatankul, student of Rachel Larsen at UCSD.
Genome structure
B. quintana’s genome is composed of a single circular chromosome containing 1,581,384 bp. In addition, 1,308 genes that have been identified only but 26 genes are unique to B. quintana. It has been recently discovered that the genome sequence of B. quintana is a derivative of the larger 1.9 Mb genome of B. henselae. B. quintana does not contain genomic islands coding for filamentous hemgglutinin found in B. henselae (14). Southern blots indicated that all five pathogenic Bartonella spp. posses hbpA homlogs, which encodes an integral membrane protein localized at the outer membrane and surface exposed. HbpA is the first potential virulence determinant characterized from B. quintana (18). In addition, both B. quintana and B. henselae genomes are shortened versions of chromosome 1 from the highly related pathogen Brucella melitensis (14).
Edited by Rani Thamawatankul, student of Rachel Larsen at UCSD.
Cell structure and metabolism
A number of bacterial pathogens have evolved for accumulating hemin in order to satisfy their iron, proporphyrin ring, or cytcochrome cofactor requirements. However, early studies with B. quintana indicated that iron is the critical component provided by hemin supplements (15). The transport of iron from hemin is a TonB-dependent process that requires the synthesis of a surface-membrane receptor to facilitate the binding of the ligand. Next, a protein in the periplasmic space transports the hemin to the cytoplasmic membrane, and finally a permease brings the molecule into the bacterial cell (16).
In early 1960’s, Vinson first cultured B. quintana in axenic media, either in blood–enriched agar or in broth with amino acids, yeast extract, and fetal bovine serum (2). These microorganisms obtain their source of energy from succinate, pyruvate, and glutamate but unable to use glucose. In addition, bicarbonate is essential for B. quintana as a source of carbon dioxide (1). Because Bartonella spp. are the only bacterial pathogens that engage in hemotrophy (erythrocyte parasitism), all Bartonella species require erythrocytes or hemin supplements in order to grow in vitro. B. quintana has the highest hemin requirement (20 to 40 µg/ml of medium) for a bacterium (15). There is a family of hemin binding proteins (HbpA, HbpB, HbpC, HbpD, and HbpE) that is synthesized by B. quintana and is served as hemin receptors (18). However, the reason for this unique characterization of B. quintana hemin requirement and mechanism is still unclear. Although HbpA plays a role in the ability of B. quintana to acquire hemin from the environment (abiotic or biotic), antibiotics specific for HbpA may inhibit the ligand-receptor interaction (17). Because HbpA is only one of the eight membrane-associated proteins in the organism, hemin binding is not abolished in the presence of anti-HbpA Fab fragments. The exact localization and involvement in iron acquisition of the additional hemin-binding membrane proteins is currently under investigation (18).
Pili and specialized extensions of the outer membrane are thought to play an important role in adhesin to nucleated cells. Pili structures in B. henselae, B. quintana, B. tribocorum, and B. alsatica posses type IV pili. Twitching motility and self-aggregation are specific properties typical for this type of pili (19).
Edited by Rani Thamawatankul, student of Rachel Larsen at UCSD.
Ecology
Describe any interactions with other organisms (included eukaryotes), contributions to the environment, effect on environment, etc.
Pathology
Treponema denticola is a bacterial pathogen and plant plastid. It causes periodontal disease and gum inflammation.
How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.
Edited by Neena Patel, student of Rachel Larsen at UCSD.
Application to Biotechnology
Does this organism produce any useful compounds or enzymes? What are they and how are they used?
Current Research
Enter summaries of the most recent research here--at least three required
References
example:
Edited by student of Rachel Larsen and Kit Pogliano
