10 Questions
What is the purpose of Bergey's Manual?
To classify and identify microorganisms
Which domain includes organisms with prokaryotic cells?
Bacteria
What distinguishes taxonomy from phylogeny?
Taxonomy provides universal names, phylogeny shows evolutionary relationships
How can a newly discovered microbe be classified by DNA fingerprinting?
By identifying its nucleic acid hybridization pattern
Which method can be used to identify an unknown bacterium through recognition of specific proteins?
Serological tests
What does a dichotomous key aim to achieve in microbiology classification?
Helping to identify organisms through a series of yes/no questions
Which method is NOT suitable for identifying microorganisms based on genetic information?
Serological tests
What is the main focus of phage typing in microbiology identification?
Determining phage susceptibility
In microbiology, what does rRNA sequencing primarily help determine?
The evolutionary relationships among microorganisms
What information does DNA fingerprinting provide for the classification of microorganisms?
Genetic relatedness
Study Notes
Taxonomy and Phylogeny
- Taxonomy: Science of classifying organisms, providing universal names for organisms
- Taxonomic categories: Taxon / Taxa
- Phylogeny or Systematics: Evolutionary history of a group of organisms
- Taxonomic hierarchy shows phylogenetic (evolutionary) relationships among organisms
- In 1969, living organisms were divided into five kingdoms
- In 1978, two types of prokaryotic cells were found, and their relationships were determined by rRNA sequencing
Classification of Microorganisms
- The three-domain system: Eubacteria, Archaea, and Eukarya
- Eubacteria: also known as "virtuosos"
- Archaea: also known as "weirdoes"
- Eukarya: also known as "predators and thieves"
- Scientific naming: binomial nomenclature (genus + specific epithet) is used worldwide
- Examples of scientific names:
- Escherichia coli
- Homo sapiens
- Klebsiella pneumoniae
- Pfiesteria piscicida
- Salmonella typhimurium
- Streptococcus pyogenes
- Penicillium chrysogenum
- Trypanosoma cruzi
Identification of Microorganisms
- Bergey's Manual: provides identification schemes for identifying bacteria and archaea
- Bergey's Manual of Determinative Bacteriology: focuses on morphology, differential staining, and biochemical tests
- Bergey's Manual of Systematic Bacteriology: focuses on phylogenetic information, based on rRNA sequencing
- Clinical laboratory identification methods:
- Morphological characteristics
- Numerical and rapid identification
- Differential staining (e.g. Gram staining, acid-fast staining)
- Biochemical tests (determines presence of bacterial enzymes)
- Serological tests:
- Involve reactions of microorganisms with specific antibodies
- Useful in determining the identity of strains and species, as well as relationships among organisms
- Examples: slide agglutination, ELISA, Western blot
- Phage typing: determines the susceptibility of bacteria to various phages
- Other identification methods:
- Ribotyping
- DNA fingerprinting
- PCR
- Nucleic acid hybridization
- DNA chips
- FISH
Species Definition
- Eukaryotic species: a group of closely related organisms that breed among themselves
- Prokaryotic species: a population of cells with similar characteristics (Bergey's Manual of Systematic Bacteriology is the standard reference on bacterial classification)
Explore the identification schemes for bacteria and archaea provided by Bergey's Manual, including morphology, differential staining, and biochemical tests. Learn about the phylogenetic information on bacteria available in Bergey's Manual of Systematic Bacteriology.
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