华中农业大学：《微生物学》课程PPT教学课件（英文版）Chapter 3 The Prokaryotes

Chapter 3 The Prokaryotes

Chapter 3 The Prokaryotes

Chapter Outline 3.1 Bacteria 3.2 Actinomycetes 3.3 Cyanobacteria 3.4 Archaeobacteria 3.5 Other prokaryotes 3.6 Classification of bacteria

Chapter Outline 3.1 Bacteria 3.2 Actinomycetes 3.3 Cyanobacteria 3.4 Archaeobacteria 3.5 Other prokaryotes 3.6 Classification of bacteria

Concepts Microorganisms are too small to be seen without the use of a microscope.The techniques-such as sterilization and the use of culture medium are required to isolate and grow these microbes. Bacteria may be spherical (cocci),rod-shaped (bacilli),spiral,or filamentous. Most bacteria can be divided into gram-positive and gram- negative groups based on their cell wall structure and response to the Gram stain.Bacteria such as mycoplasmas lack a cell wall

Concepts • Microorganisms are too small to be seen without the use of a microscope. The techniques-such as sterilization and the use of culture medium are required to isolate and grow these microbes. • Bacteria may be spherical (cocci), rod-shaped (bacilli), spiral, or filamentous. • Most bacteria can be divided into gram-positive and gram￾negative groups based on their cell wall structure and response to the Gram stain. Bacteria such as mycoplasmas lack a cell wall

3.1 Bacteria Size,Shape,and Arrangement of Bacterial Cells Most bacteria fall within a range Cm=10-2meter from 0.2 to 2.0 um in diameter mm =10-3meter μm=10-6 meter and from 2 to Sum in length. nm=10-9meter They have a few basic shapes-spherical coccus (plural,cocci,meaning berries),rod-shaped bacillus (plural,bacilli,meaning little staffs),and spiral

Size, Shape, and Arrangement of Bacterial Cells They have a few basic shapes-spherical coccus (plural, cocci, meaning berries), rod-shaped bacillus (plural, bacilli, meaning little staffs), and spiral. Cm = 10-2 meter mm = 10-3 meter μm = 10-6 meter nm = 10-9 meter 3.1 Bacteria Most bacteria fall within a range from 0.2 to 2.0 μm in diameter and from 2 to 8μm in length

Representative Cell Shapes(Morphology)in Prokaryotes Budding and appendaged bacteria

How to identify an unknown bacterial species Factors: ·Morphology(shape) Chemical composition (often detected by staining reactions) Nutritional requirements 。 Biochemical activities Source of energy (sunlight or chemicals)

• Morphology (shape) • Chemical composition (often detected by staining reactions) • Nutritional requirements • Biochemical activities • Source of energy (sunlight or chemicals) How to identify an unknown bacterial species ? Factors:

Arrangement of Spherical Bacterial Cells diplococci streptococci tetracocci sarcinae staphylococci

Arrangement of Spherical Bacterial Cells

The Micrococcaceae The family Micrococcaceae contains gram-positive cocci,0.5-2.5 um in diameter,that divide in more than one plane to form regular or irregular clusters of cells.All are aerobic or facultatively anaerobic.The peptidoglycan di- amino acid is L-lysine. The three most important genera are: 1.Micrococcus 2.Staphylococcus 3.Streptococcus

The Micrococcaceae 1. Micrococcus 2. Staphylococcus 3. Streptococcus The family Micrococcaceae contains gram-positive cocci, 0.5-2.5 μm in diameter, that divide in more than one plane to form regular or irregular clusters of cells. All are aerobic or facultatively anaerobic. The peptidoglycan di￾amino acid is L-lysine. The three most important genera are:

Micrococcus-aerobic,gram-positive,catalase positive,cell arranges mainly in pairs,tetrads,or irregular clusters,nonmotile.They are often yellow, orange or red in color

Micrococcus – aerobic, gram-positive, catalase positive, cell arranges mainly in pairs, tetrads, or irregular clusters, nonmotile. They are often yellow, orange or red in color

staphylococci staphylococci Staphylococcus-facultatively anaerobic,gram- positive,usually form irregular clusters,nonmotile, catalase positive but oxidase negative,ferment glucose anaerobically

Staphylococcus - facultatively anaerobic, gram￾positive, usually form irregular clusters, nonmotile, catalase positive but oxidase negative, ferment glucose anaerobically. staphylococci staphylococci