L10- Yersinia Pestis- Micro 4120

Micro 4120 Exam 1

Characteristics of Y. pestis

gram-negative rod, bacteria, causative agent of the bubonic plague. Transmitted via fleas, rats are carriers.

Non-virulent strain KIM-D27 (pgm deficient)

An attenduated strain used for vaccines, missing 100 kilobases of it genome that encode for protein in the biosynthetic pathway of Yersiniabactin, which is a siderophore that scavenges iron and as such is a virulence factor

How the researcher was able to contract Y. pestis via KIM-D27

the researcher had hemochromastasis, which means there is a high level of iron in the blood. this allows Y. pestis to overcome the loss of Yersiniabactin and become virulent again.

Ways iron can be found

By itself (superoxide dismutase, methane monooxygenase), as a part of cofactors containing other types of metals (nitrogenases, hydrogenases), as a part of iron-sulfur clusters (ferredoxin), and as a part of organic cofactors (heme-containing enzymes/proteins).

Siderophores

low molecular weight molecules that are synthesized by bacteria/fungi and are excreted into the medium to sequester ferric iron (Fe 3+). Many different types of siderophores created and used by organisms, and each take up they type of siderophores they create

Siderophore makeup

3 components: The TonB-dependent outer membrane protein/receptor (allows active transport of iron or iron-containing substance across the outer membrane and into the periplasm). TonB-ExbB-ExbD complex (transmits the energy from the PMF to the membrane transporter in the outer membrane). ABC transporter (captures the iron once it is in the periplasm and transports it across the cytoplasmic membrane)

Methods for iron sequestering/scavenging

produce and secrete siderophores together with a siderophore receptor on the cell surface, bind an iron-protein to the cell-surface receptor and extract the iron, take up iron-bound molecules directly, bind a heme-containing protein to a cell-surface receptor and extract heme for transport, produce and secrete heme-binding proteins to sequester heme bound to hemoglobin.