20 - 12/27/11 microbiology 8-year course 1 Chlamydiae...

Info iconThis preview shows pages 1–10. 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

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

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: 12/27/11 microbiology 8-year course 1 Chlamydiae 12/27/11 microbiology 8-year course 2 Biological Features Structure and chemical composition Developmental cycle Staining properties Antigens Growth and metabolism Characteristics of host-parasite relationship Classification 12/27/11 microbiology 8-year course 3 Structure and chemical composition a nonreplicating, infectious particle called the elementary body (EB) an intracytoplasmic form called the reticulate body (RB) 12/27/11 microbiology 8-year course 4 Structure and chemical composition 12/27/11 microbiology 8-year course 5 Structure and chemical composition The elementary body, which is covered by a rigid cell wall, contains a DNA genome with a molecular weight of 66 X 107 (about 600 genes, one-quarter of the genetic information present in the DNA of Escherichia coli ). A cryptic DNA plasmid (7,498 base pairs) is also found. It contains an open reading frame for a gene involved in DNA replication. the elementary body contains an RNA polymerase responsible for the transcription of the DNA genome after entry into the host cell cytoplasm and the initiation of the growth cycle. Ribosomes and ribosomal subunits are present in the elementary bodies. Throughout the developmental cycle, the DNA genome, proteins, and ribosomes are retained in the membrane-bound reticulate body. 12/27/11 microbiology 8-year course 6 Developmental cycle EBs attach to the microvilli of susceptive cells. Penetration into the host cell via endocytosis or pinocytosis and forming phagosomes Fusion of lysomes with the EB-containing phagosome are inhibited EBs reorganize into the metabolically active RBs. RBs synthesize their own DNA, RNA and protein but lack the necessary metabolic pathways to produce high-energy phosphate compounds. Energy parasites . RBs replicate by binary fission and inclusion forms. RBs begin reorganizing into EBs. Cell ruptures and releasesthe infective Ebs. The developmental cycle takes 24 48 hours. 12/27/11 microbiology 8-year course 7 Developmental cycle 12/27/11 microbiology 8-year course 8 Staining properties EBs stain purple with Giemsa stain in contrast to the blue of host cell cytoplasm. RBs stain blue with Giemsa stain. The Gram reaction of chlamydiae is negative or variable and is not useful in identification. Inclusions stain brightly by immunofluorescence ,with group-specific,species-specific, or serovar-specific antibodies. 12/27/11 microbiology 8-year course 9 Antigens Group(fenus)-specific antigens: heat-stable LPS as an immunodominant component. Antibody to these antigens can be detected by CF and immunofluorescence Species-specific or serovar-specific antigens Antigens are mainly outer membrane proteins(MOMP)....
View Full Document

This note was uploaded on 12/27/2011 for the course STEP 1 taught by Professor Dr.aslam during the Fall '11 term at Montgomery College.

Page1 / 42

20 - 12/27/11 microbiology 8-year course 1 Chlamydiae...

This preview shows document pages 1 - 10. Sign up to view the full document.

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