Most Pathogens That Acquire Access By Way Of The Pores And Skin
Few, if any, other microbial products have been as extensively studied as bacterial endotoxins. Perhaps it’s applicable that a molecule with such essential biologic effects on the host, and one produced by so many bacterial pathogens, should be the subject of intense investigation. Some micro organism (e.g., Rickettsia species) can develop solely within eukaryotic cells, whereas others (e.g., Salmonella species) invade cells however do not require them for development.
A) Body temperature is reset in the hypothalamus.B) Fever occurs.C) IL-1 is released.D) LPS is released from gram-negative micro organism.E) Phagocytes ingest gram-negative micro organism. All of the next micro organism release endotoxin EXCEPTA) Clostridium botulinum.B) Salmonella typhi.C) Neisseria meningitidis.D) Proteus vulgaris.E) Haemophilus influenzae. Which of the next statements about staphylococcal enterotoxin is FALSE? A) It causes vomiting.B) It causes diarrhea.C) It is an exotoxin.D) It is produced by Staphylococcus aureus growing in the host’s intestines.E) It is a superantigen. The fimbriae of Neisseria gonorrhea and enteropathogenic E.
Generally, The Ld50 For Exotoxins Is Much Higher Than The Ld50 For Endotoxins
Other bacteria have evolved elaborate mechanisms to extract the iron from host proteins (Fig. 7-6). Siderophores are substances produced by many bacteria to seize iron from the host. The absence of iron triggers transcription of the genes coding for the enzymes that synthesize siderophores, as well as for a set of surface protein receptors that recognize siderophores carrying certain iron. The binding constants of the siderophores for iron are so high that even iron certain to transferrin and lactoferrin is confiscated and brought up by the bacterial cells.
The release of apo-HasA from the receptor is performed in an power-driven process by HasB (Paquelin et al., 2001). This recycling process for HasA is only noticed within the presence of heme, which can also be required for the induction of hasB expression (Rossi et al., 2003; Wandersman and Delepelaire, 2012). The Has system is negatively regulated by iron and Fur, and positively regulated by a sigma and anti-sigma signaling cascade triggered by heme-loaded hemophore binding to HasR (Rossi et al., 2003; Cwerman et al., 2006). Systems with similarity to Has have been reported in P. aeruginosa (Letoffe et al., 1998), P. fluorescens (Idei et al., 1999), and Y. The contribution of the Has system to the virulence of Y.