Group XIV – Sheathed Bacteria
An important genus here is Sphaerotilus. Another is Leptothrix.
Motile bacteria join together and encase themselves in a sheath. Its flagella are lophotrichous (several at one pole). As cells reproduce by binary fisson, the sheath gets longer. When nutrients are exhausted, the bacteria leave the sheath.
This organism tends to form in steams when there is leaf fall. It uses many type of organic matter as its nutrients.
Sometimes it is referred to as ‘Sewage Fungus’ although it is not a fungus.
Leptothrix oxidizes FE2+ and Mn2+.
Group XV – Budding and Stalked Bacteria
In these bacteria, cell growth is not by binary fission. Rather at a single point on the ‘mother’ cell, and entirely new cell is formed. Genera that multiply in this way include:
• Hyphomicrobium
• Rhodomicrobium
Grown and reproduction of Hyphomicrobium
are seen in Appendix 7. Hyphomicrobium is a chemolithotroph. Rhodomicrobium is a budding bacterium that is phototrophic (it gets energy from light).
Stalked bacteria form structures (stalks) that are used to attach to solid objects. Genera that do this include:
• Caulobacter
• Gallionella
Reproduction of Caulobacter is depicted in Appendix 8. ภาษาไทย