Identifying Human Host Cell Protein Targets of the Bartonella Effector Protein (Bep) Fic Domains

<p>The genus Bartonellae represents an increasing number of emerging bacterial pathogens that utilises an unusual infection strategy, parasitising the red blood cells of their mammalian host. The most common species to infect humans are B. henselae and B. quintana. B. henselae is transmitted between cats by the cat flea, although occasionally infects humans via cat scratches or bites, causing cat-scratch disease (CSD). CSD is characterised by enlarged tender lymph nodes and fever. B. henselae also infects the endothelial cells of both its hosts; likely a factor in disease progression. B. quintana, the cause of trench fever during WWI, is spread people by the body louse. Trench fever is characterised by relapsing fever, headache, and bone pain. B. quintana is also able to infect human endothelial cells. These bacteria secrete a range of Bartonella effector proteins (Beps) via a Type IV secretion system, directly into endothelial cells, subverting host cell processes and resulting in internalisation of the bacteria. Beps have a range of functions, many of which are not fully characterised. B. henselae secretes three Beps (BepA-C) that contain a filamentation induced by cAMP (Fic) domain and a Bartonella Intracellular Delivery (BID) domain, with BepA being the best studied. BepA’s BID domain is responsible for intracellular delivery as well as inhibition of apoptosis by the host cell, however the exact function of the Fic domain remains unknown. Fic-containing bacterial toxins catalyse the transfer of an AMP moiety from ATP onto a host cell protein. This AMPylation frequently inactivates these proteins resulting in disrupted host cell processes and cytotoxicity. BepA has previously been shown to possess AMPylation activity, although the host target protein(s) are unknown. Evidence suggests that these proteins are novel targets. The aim of this study was to create protein constructs containing these Fic domains, and to develop techniques to identify the host cell target proteins post AMPylation. To this end, both a fluorescent ATP analogue and a fluorescent click chemistry based approach were utilised. While no target protein was identified, a basic methodology was developed for protein production and target protein identification that could be further developed.</p>

Identifying Human Host Cell Protein Targets of the Bartonella Effector Protein (Bep) Fic Domains

<p>The genus Bartonellae represents an increasing number of emerging bacterial pathogens that utilises an unusual infection strategy, parasitising the red blood cells of their mammalian host. The most common species to infect humans are B. henselae and B. quintana. B. henselae is transmitted between cats by the cat flea, although occasionally infects humans via cat scratches or bites, causing cat-scratch disease (CSD). CSD is characterised by enlarged tender lymph nodes and fever. B. henselae also infects the endothelial cells of both its hosts; likely a factor in disease progression. B. quintana, the cause of trench fever during WWI, is spread people by the body louse. Trench fever is characterised by relapsing fever, headache, and bone pain. B. quintana is also able to infect human endothelial cells. These bacteria secrete a range of Bartonella effector proteins (Beps) via a Type IV secretion system, directly into endothelial cells, subverting host cell processes and resulting in internalisation of the bacteria. Beps have a range of functions, many of which are not fully characterised. B. henselae secretes three Beps (BepA-C) that contain a filamentation induced by cAMP (Fic) domain and a Bartonella Intracellular Delivery (BID) domain, with BepA being the best studied. BepA’s BID domain is responsible for intracellular delivery as well as inhibition of apoptosis by the host cell, however the exact function of the Fic domain remains unknown. Fic-containing bacterial toxins catalyse the transfer of an AMP moiety from ATP onto a host cell protein. This AMPylation frequently inactivates these proteins resulting in disrupted host cell processes and cytotoxicity. BepA has previously been shown to possess AMPylation activity, although the host target protein(s) are unknown. Evidence suggests that these proteins are novel targets. The aim of this study was to create protein constructs containing these Fic domains, and to develop techniques to identify the host cell target proteins post AMPylation. To this end, both a fluorescent ATP analogue and a fluorescent click chemistry based approach were utilised. While no target protein was identified, a basic methodology was developed for protein production and target protein identification that could be further developed.</p>

Written on the Body

This chapter examines the language of illness, sickness, and death in war-time use – in a domain which offered its own conflicted spaces of both erasure and over-lexicalisation, and euphemism alongside dysphemism. As Clark’s ‘Words in War-Time’, records, popular discourses of health readily appropriated military metaphors in ways that evoked other synergies between Home and active fronts (‘If your line of health is “weakly held” strengthen your forces with Bovril’, as advertising in the Scotsman announced in March 1915). In contrast, human vulnerabilities as embedded in trench warfare as literal rather than metaphorical process yielded a rapidly expanding lexicon, evident in the shifting understanding of trench foot, trench fever, and frostbite, or the reorientation of the diction of nerves and nerviness in which shellshock (and raid-shock on the Home Front) can remain prominent legacies.

Five millennia of Bartonella quintana bacteremia

ABSTRACTBartonella quintana caused trench fever in the framework of two World Wars and is now recognized as an agent of re-emerging infection. Many reports indicated the popularity of B. quintana exposure since the 90s. For evaluating its prevalence in ancient populations, we used real-time PCR to detect B. quintana DNA in 400 teeth collected from 145 individuals dating from the 1st to 19th centuries in nine archeological sites with the presence of negative controls. Fisher’s exact test was used to compare the prevalence of B. quintana detection in civil and military populations. B. quintana DNA was confirmed in a total of 28/145 (19.3%) individuals, comprising 78 citizens and 67 soldiers, 20.1% and 17.9% of which were positive for B. quintana bacteremia, respectively. This study collected previous studies on these ancient samples and showed that the presence of B. quintana infection followed the course of time in human history; a total of 14/15 sites from five European countries had a positive prevalence. The positive rate in soldiers was higher than those of citizens, with 20% and 18.8%, respectively, in the 18th - 19th centuries, but the difference in frequency was not significant. These results confirmed the role of dental pulp in diagnosing B. quintana bacteremia in ancient populations and showed the incidence of B. quintana in both citizens and soldiers. Many recent findings contributed to understanding the coevolution of the relationship between B. quintana and humans.