《微生物学》课程教学课件（PPT讲稿）The impact of microorganisms on human affairs

The impact of microorganisms on human affairs Agriculture Food N2 fixation Food preservation Nutrient cycling Fermented foods Animal husbandry Food additives Disease Identifying new diseases Treatment and cure Disease prevention Energy/Environment Biotechnology Biofuels (methane and ethanol) Bioremediation Genetically modified organisms Microbial mining Production of pharmaceuticals Gene therapy for certain diseases

The impact of microorganisms on human affairs

Important Persons in Microbiology History 1684 Antonie van Leeuwenhoek(discovery of bacteria) 1857-1864 Louis Pasteur(lactic acid fermentation, yeast alcohol fermentation, spontaneous generation theory “ swan neck flasks”) 1881-1884 Robert Koch(pure culture, cause of tuberculosis, Koch's postulates, cause of (EEL) cholera 1889 Martinus Beijerinck(concept of a virus) 1929 Alexander Fleming(discovery of penicilin) 1953 James Watson, Francis Crick(DNA structure) 1983 Luc Montagnier( discovery of HIv)

Important Persons in Microbiology History 1684 Antonie van Leeuwenhoek (discovery of bacteria) 1857-1864 Louis Pasteur (lactic acid fermentation, yeast alcohol fermentation, spontaneous generation theory “swan neck flasks”) 1881-1884 Robert Koch (pure culture, cause of tuberculosis, Koch’s postulates, cause of (霍乱) cholera） 1889 Martinus Beijerinck (concept of a virus) 1929 Alexander Fleming (discovery of penicilin) 1953 James Watson, Francis Crick (DNA structure) 1983 Luc Montagnier (discovery of HIV)

Prokaryotic Cell (versus Eukaryotic Cell) Not compartmentalized Cell membranes lack sterols(e.g. cholesterol) Single circular chromosome Ribosomal are 70s with subunits 30S (16S rRNA) 50s(5s& 23s rRNA)

Prokaryotic Cell (versus Eukaryotic Cell) • Not compartmentalized • Cell membranes lack sterols (e.g. cholesterol) • Single circular chromosome • Ribosomal are 70S with – subunits 30S (16S rRNA) – 50S (5S & 23S rRNA)

2. Shape and arrangement Coccus or Cocci R pirillum or spirilla Spirochete Budding and appendaged coding and appendaged t Filamentous

Coccus or Cocci Rod Spirillum or Spirilla Spirochete Budding and appendaged Filamentous 2.Shape and arrangement

Procaryoic cell organization Flagello Granular inclusion Ribosomes Cell aQ wall / outer membrane(if present Cytoplasmic Cytoplasm Capsule membrane Nucleoid Mesosome

Procaryoic cell organization

Mesosome invagination of the plasma membrane in the shape of vesicles, tubules, or lamellae Functions 1. cell wall formation during division 2. play a role in chromosome replicaton and distribution to daughter cells

Mesosome: invaginationa of the plasma membrane in the shape of vesicles, tubules, or lamellae. Functions: 1.cell wall formation during division. 2.play a role in chromosome replicaton and distribution to daughter cells

Making Wall-less forms Result from action of -enzymes lytic for cell wall -antibiotics inhibiting peptidoglycan biosynthesis Wall-less bacteria that dont replicate -spheroplasts (with outer membrane)? protoplasts(no outer membrane).? Wall-less bacteria that replicate -L forms Naturally Wall-less Genus Mycoplasma

Making Wall-less forms • Result from action of: –enzymes lytic for cell wall –antibiotics inhibiting peptidoglycan biosynthesis • Wall-less bacteria that don’t replicate: –spheroplasts (with outer membrane)? –protoplasts (no outer membrane). ? • Wall-less bacteria that replicate –L forms Naturally Wall-less Genus Mycloplasma

INCLUSIONS Within the cytoplasm of procaryotic(and eucaryotic) cells are several kinds of reserve deposits, known as inclusions. Some inclusions are common to a wide variety of bacteria. whereas others are limited to a small number of species and therefore serve as a basis for identification. Among the more prominent bacterial inclusions are the following Carbon storage polymers- PHB and glycogen Phosphate polymers Sulfur granules Gas Vacuoles

Within the cytoplasm of procaryotic (and eucaryotic) cells are several kinds of reserve deposits, known as inclusions. Some inclusions are common to a wide variety of bacteria, whereas others are limited to a small number of species and therefore serve as a basis for identification. Among the more prominent bacterial inclusions are the following: Carbon storage polymers – PHB and glycogen Phosphate polymers Sulfur Granules Gas Vacuoles INCLUSIONS

Gram Positive Gram Negative Fixation Crystal violet lodine treatment Decolorization Counter stain safranin

L-alanine D-glutamic acid L-lysine/Diaminopimelic acid D-alanine D-alanine Peptidoglycan ○○○ Muramic acid Glucosamine

Peptidoglycan Muramic acid Glucosamine L-alanine D-glutamic acid L-lysine/Diaminopimelic acid D-alanine D-alanine