MODULE 9 - MODULE 9 9a) Vibrio, Rickettsias and Spirilla...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: MODULE 9 9a) Vibrio, Rickettsias and Spirilla Vibrio and Photobacterium Vibrio: important human pathogen o Gram-negative, facultatively aerobic rods o Found mainly in fresh water or marine aquatic environments o Virbio cholera is human pathogen causing disease cholera, usually associated with poor water sanitation o Number of Vibrio strains that are not pathogenic Some are bioluminescent and associated with fish or squid Bioluminescence requires lucifersae enzyme Produced as result of gene expression at high population concentrations Rickettsias Most are obligate intracellular parasites Infect both humans and animals Closely related to mitochondria Can only replicate within host cell Mitochondria evolved from organisms that probably had similar relationship with their host cell Cause diseases Rocky mountain spotted fever and Q fever Have very restricted energy metabolism Many can only use glutamine and glutamate as nutrients which they acquire form host Rickettsias often transmitted by arthropod vectors Spirilla Spiral shaped bacteria Classified based on their spiral cell shape Very phylogenetically diverse grouping: all five subdivisions have been found to have this cell shape Members of this grouping may be distributed among other groups in future as other characteristics are considered in classification Bdellovibrio, of delta phylogenetic group o Attaches to prey bacteria o Introduced in periplasmic space o Multiply o Requirements: host organism gram-negative 9b) Budding and Stalked Bacteria and Gliding Myxobacteria Group of bacteria grouped together based on their cell type or division These organisms have unequal cell division in which division occurs in one region of the cell where a bud forms Most alpha, but some beta and gamma Unequal Cell Division Binary fission: rod shaped organism that elongates, septum forms, two cells that are identical Polar growth: growth only at one end of cell, parental cell still exists as well as daughter cell Simple budding: smaller bud that results in formation of daughter cell Budding from hyphae: long extrusion that forms, bud forms at end of that, bud comes off and then bud formation again Cell division of stalked organism Caulobacter: swarm of cells Stages in Hyphomicrobium cell cycle o Hyphae will form and lengthen o Copy of chromosome enters hyphae and travels toward forming bud o Forms swarmer cell, which matures and can swim away, can differentiate back in a non-swarmer cell o Parent cell with hyphae can continue to form buds Stages in Caulobacter cell cycle o Stalked cell is the only cell that can divide o Swarmer cell- loss of flagellum to form stalked cell o Stalked cell can then bud off swarmer cell Gliding Myxobacteria o Organisms that have a complex behaviour and development o Can communicate with each other and their development is dependent on this communication o Have very large chromosome because of complicated developmental process...
View Full Document

Page1 / 10

MODULE 9 - MODULE 9 9a) Vibrio, Rickettsias and Spirilla...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online