Identifying Bacteria and Prokaryotes

Identifying Bacteria

• Bergey's Manual of Determinative Bacteriology provides identification schemes for bacteria and archaea based on morphology, differential staining, and biochemical tests.
• Bergey's Manual of Systematic Bacteriology provides phylogenetic information on bacteria and archaea based on rRNA sequencing.

Laboratory Identification

• Morphological characteristics are useful for identifying eukaryotes.
• Numerical and rapid identification methods are used.
• Differential staining techniques include Gram staining and acid-fast staining.
• Biochemical tests determine the presence of bacterial enzymes.

Serology

• Involves reactions of microorganisms with specific antibodies.
• Useful for identifying strains and species, and determining relationships among organisms.
• Techniques include slide agglutination, ELISA, and Western blot.

Phage Typing

• Involves determining the susceptibility of bacterial species and strains to various phages.

Genetics

• DNA fingerprinting: uses restriction enzymes to produce DNA fragments (fingerprints) to determine genetic similarities.
• Ribotyping: uses rRNA sequencing to identify organisms.
• Polymerase chain reaction (PCR) amplifies small amounts of microbial DNA in a sample.

Nucleic Acid Hybridization

• Involves the bonding of single-stranded DNA or RNA from related organisms to form a double-stranded molecule.
• Applications include Southern blotting, DNA chips, and Fluorescent In Situ Hybridization (FISH).

Taxonomy

• The Three-Domain System: Eubacteria, Archaea, and Eukarya.
• Endosymbiotic Theory: explains the origin of eukaryotes.

Scientific Nomenclature

• Common names vary with language and geography.
• Binomial Nomenclature (genus + specific epithet) is used worldwide and is a universal standard.
• Examples of scientific names include Escherichia coli and Homo sapiens.