Abstract only
The onset of irreversible shock upon exposure to certain pathogens can progress rapidly from onset of flu‐like symptoms to near‐untreatable illness. Our approach has been to ...characterize host responses, an approach that offers other benefits that include assessment of “progression of illness”. This can take into account not only time post‐exposure, but also exposure level and susceptibility due to personal factors. Our studies have characterized host gene expression responses to biological threat pathogenic agents as well as to common influenza and other flu‐like pathogens in order to gain an understanding of host responses that lead to irreversible, critical illness. These studies integrate the clinical pathophysiological findings with host‐omics, from 1–72 h post‐exposure, developing algorithms to correlate these massive datasets with the progression of illness and identification of early indicators of impending vascular leakage and eventual collapse. Definition of the biosignatures at various stages during the progression to lethality have revealed stage‐appropriate therapeutic targets have the potentialo to be used for intervention strategies.
Cell fusing agent virus (CFAV) is a positive strand RNA insect virus first isolated from a mosquito cell line. Based on viral morphology, phenotypic and phylogenetic studies, CFAV had been ...tentatively assigned to the genus Flavivirus (family Flaviviridae). The determination of the CFAV polyprotein complete sequence showed a putative serine protease domain analogue to the flaviviral NS2B/NS3 complex. This complex had been extensively studied, because it represented one of the main targets for antiflavivirus therapy development. We report herein the biochemical characterization of CFAV ΔNS2B-NS3pro protease complex. CFAV polyprotein sequence was computationally analysed to identify the amino-acid regions involved in protease activity. We designed, expressed and purified a catalytically active protease whose enzymatic properties were determined using fluorogenic substrates. Our results showed that, despite the low level of conservation of its amino-acid sequence, CFAV protease exhibited physico-chemical properties of other flaviviruses (high pH value requirement for optimal activity, inhibition by salt and preference for substrates featuring a basic residue at P₁ position).
We have found the domestic Yorkshire piglet (Sus scrofa) a suitable animal model for researching the pathogenesis of Staphylococcus enterotoxin B (SEB) and have used this model to demonstrate gross, ...histological and various clinical diagnostic parameters (body temp‐T, blood pressure‐BP, blood gasses‐BG) to characterize the clinical syndrome of SE intoxication. In this report we use thrombelastography (TEG) to investigate an additional clinical parameter in this model‐ the blood coagulation and fibrinolytic system to investigate coagulation changes. TEG is used to characterize, in vitro, formation and strength of the blood clot over time measuring the time to initial clot formation (r), evaluate a developing clot acceleration phase (k, α‐angle), strengthening (MA) and retraction. Thirty five 2–3 week old domestic piglets, approx. 4–8kg were injected intravenously with 300ug/kg purified SEB and then closely monitored for clinical progression of SEB intoxication using T, BP, BG and TEG to monitor SEB intoxication and track coagulation changes between 0 and 72 hours. Blood was drawn for baseline TEG analysis prior to SEB intoxication (n=33) and at various time points following intoxication. Our results demonstrate the piglets become significantly hypocoagulable (r, k, α‐angle values) following SEB intoxication by 36 hour then hypercoagulable after 48 hrs. This report may be the first use of TEG to assess the coagulation changes in SE induced shock in a porcine model.
Crimean-Congo hemorrhagic fever virus (CCHFV) is a virus that causes severe liver dysfunctions and hemorrhagic fever, with high mortality rate. Here, we show that CCHFV infection caused a massive ...lipidation of LC3 in hepatocytes. This lipidation was not dependent on ATG5, ATG7 or BECN1, and no signs for recruitment of the alternative ATG12-ATG3 pathway for lipidation was found. Both virus replication and protein synthesis were required for the lipidation of LC3. Despite an augmented transcription of SQSTM1, the amount of proteins did not show a massive and sustained increase in infected cells, indicating that degradation of SQSTM1 by macroautophagy/autophagy was still occurring. The genetic alteration of autophagy did not influence the production of CCHFV particles demonstrating that autophagy was not required for CCHFV replication. Thus, the results indicate that CCHFV multiplication imposes an overtly elevated level of LC3 mobilization that involves a possibly novel type of non-canonical lipidation.
Abbreviations: BECN1: Beclin 1; CCHF: Crimean-Congo hemorrhagic fever; CCHFV: Crimean-Congo hemorrhagic fever virus; CHX: cycloheximide; ER: endoplasmic reticulum; GFP: green fluorescent protein; GP: glycoproteins; MAP1LC3: microtubule associated protein 1 light chain 3; MOI: multiplicity of infection; n.i.: non-infected; NP: nucleoprotein; p.i.: post-infection; SQSTM1: sequestosome 1
A first outbreak of Ebola virus in West Africa Reynard, Olivier; Volchkov, Viktor; Peyrefitte, Christophe
M.S. Médecine sciences,
2014 Jun-Jul, 20140601, Letnik:
30, Številka:
6-7
Journal Article
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