Bacteria are classified into four categories according to shared characteristics, these categories are then divided into groups, and the groups are divided further into subgroups. The ninth group of bacteria contains only two sub

The developmental cycle ends with the release of the chlamydiae from the host cell. Several modes of release have been proposed but it is unclear what actually happens (3). One mode of release is lysis of the host cells followed by the release of the chlamydiae. In this mode of release the inclusions burst inside the host cell, disrupting host cellular organelles. Another mechanism of release "in some host cells is as follows; the inclusion is extruded through a focal distention of the cytoplasmic membrane of the host cell without apparently affecting the rest of the cell surface" (3). Here the host cell continues its normal functions and is not destroyed. The inclusion must somehow be opened outside of the cell, possible by lysis caused by the growing bodies within it. In both cases there is no preferential release of elementary bodies and reticulate bodies and intermediate bodies are also released at the same time. At this point the elementary bodies continue the cycle anew by infecting new host cells.

In the sense that chlamydiae change form between infecting and multiplying they can be compared to viruses. Viruses have extracellular and intracellular forms. In the extracellular form the virus is in the form described in the previous paragraph. When the virus infects the host cell it leaves behind its capsid and envelope so that only its nucleic acid enters the host cell. The viral nucleic acid is replicated by host cell machinery. So both chlamydiae and viruses, including the herpesviruses, have an extracellular form that attaches to the host cell and an intracellular form that replicates or is replicated in the host cell.

Translocase activity in intracellular parasites was first demonstrated in R. prowazekii by Winkler (1976). Within host cells the rickettsiae received ATP from their host by exchanging an ADP for it, but if the host ATP was unavailable the rickettsiae would make the ATP on their own. Chlamydiae exchange ADP for host ATP just as the rickettsiae but they are unable to synthesize their own ATP. Viruses, including the Herpes virus have no metabolic capacity of their own, they must always use host machinery to get energy and for the synthesis of all their macromolecules.

Before discussing the host-parasite interactions the developmental cycle of chlamydiae need to be mentioned briefly. Chlamydiae alternate between two cell types called elementary bodies and reticulate bodies. The elementary bodies are released from infected host cells and enter uninfected host cells. In

Some common words found in the essay are:
Bacteria Chlamydias, ATP Viruses, Disease Chlamydia, Rickettsia Herpes, host cell, host cells, reticulate bodies, elementary bodies, Rickettsias Chlamydias, References Cited, James Rickettsia, Prentice Hall, chlamydiae host, bodies reticulate, chlamydial cell, Madigan Michael, Williams Williams, bodies reticulate bodies, chlamydiae host cells, bodies elementary, cell walls, outer membrane, bodies elementary bodies, chlamydial cell walls, bodies intermediate bodies,
Approximate Word count = 1722
Approximate Pages = 7 (250 words per page double spaced)