Transcriptomics of Haemophilus (Glässerella) parasuis serovar 5 subjected to culture conditions partially mimetic to natural infection for the search of new vaccine antigens

11 p.Haemophilus (Glässerella) parasuis is the etiological agent of Glässer’s disease in pigs. Control of this disorder has been traditionally based on bacterins. The search for alternative vaccines has focused mainly on the study of outer membrane proteins. This study investigates the transcriptome of H. (G.) parasuis serovar 5 subjected to in vitro conditions mimicking to those existing during an infection (high temperature and iron-restriction), with the aim of detecting the overexpression of genes coding proteins exposed on bacterial surface, which could represent good targets as vaccine candidates. The transcriptomic approach identified 13 upregulated genes coding surface proteins: TbpA, TbpB, HxuA, HxuB, HxuC, FhuA, FimD, TolC, an autotransporter, a protein with immunoglobulin folding domains, another large protein with a tetratricopeptide repeat and two small proteins that did not contain any known domains. Of these, the first six genes coded proteins being related to iron extraction. Six of the proteins have already been tested as vaccine antigens in murine and/or porcine infection models and showed protection against H. (G.) parasuis. However, the remaining seven have not yet been tested and, consequently, they could become useful as putative antigens in the prevention of Glässer’s disease. Anyway, the expression of this seven novel vaccine candidates should be shown in other serovars different from serovar 5.S

Heme Degrading Protein HemS Is Involved in Oxidative Stress Response of Bartonella henselae

Bartonellae are hemotropic bacteria, agents of emerging zoonoses. These bacteria are heme auxotroph Alphaproteobacteria which must import heme for supporting their growth, as they cannot synthesize it. Therefore, Bartonella genome encodes for a complete heme uptake system allowing the transportation of this compound across the outer membrane, the periplasm and the inner membranes. Heme has been proposed to be used as an iron source for Bartonella since these bacteria do not synthesize a complete system required for iron Fe3+uptake. Similarly to other bacteria which use heme as an iron source, Bartonellae must transport this compound into the cytoplasm and degrade it to allow the release of iron from the tetrapyrrole ring. For Bartonella, the gene cluster devoted to the synthesis of the complete heme uptake system also contains a gene encoding for a polypeptide that shares homologies with heme trafficking or degrading enzymes. Using complementation of an E. coli mutant strain impaired in heme degradation, we demonstrated that HemS from Bartonella henselae expressed in E. coli allows the release of iron from heme. Purified HemS from B. henselae binds heme and can degrade it in the presence of a suitable electron donor, ascorbate or NADPH-cytochrome P450 reductase. Knocking down the expression of HemS in B. henselae reduces its ability to face H2O2 induced oxidative stress

Acute Phase Proteins and Stress Hormone Responses in Patients with Newly Diagnosed Active Pulmonary Tuberculosis

INTRODUCTION : Despite the high burden of disease, there have been surprisingly few studies of the acute phase and plasma catecholamine/cortisol stress hormone responses in patients with active pulmonary tuberculosis. We wished to document acute phase reactant and stress hormone responses in patients with newly diagnosed, active pulmonary tuberculosis and to compare these responses to those of a group of surgical/medical cases with conditions other than tuberculosis. METHODS : This was a prospective study of consecutive patients with newly diagnosed pulmonary tuberculosis, admitted to a tertiary hospital in Johannesburg, South Africa, documenting demographic, clinical, routine laboratory, acute phase protein and stress hormone responses relative to those of the control group. RESULTS : TB patients had a higher body temperature and pulse rate, as well as a platelet counts, ferritin, CRP and dopamine levels, with a tendency to higher cortisol levels compared to the control group. Conversely, they had a lower BMI, haemoglobin, leucocyte count, MCV and epinephrine levels than the control group. CONCLUSIONS : Patients with active pulmonary tuberculosis were documented to mount an acute stress response which was more intense than that of a control group of patients with surgical/medical conditions other than tuberculosis.National Research Foundation of South Africahttp://link.springer.com/journal/4082016-02-28hb201