微生物教程周德庆第三版课件chapter2 -1.pptVIP

Chapter 2 and Function Section 1 Bacteria I. Shape and Arrangement cocci rods (bacilli) vibrios helices spirilla Spirochaeta I. Shape and Arrangement I. Shape and Arrangement I. Shape and Arrangement I. Shape and Arrangement I. Shape and Arrangement II. Size II. Size III. Cell Structure and Function Peptidoglycan subunit composition (5) Aicd-fast staining and cell wall of acid-fast bacteria Acid-fast staining is another important differential staining procedure. A few species, particularly those in the genus Mycobacterium do not bind simple stains readily and must be stained by a harsher treatment: heating with a mixture of basic fuchsin and phenol (the Ziehl-Neelsen method). Once carbol fuchsin has penetrated with the aid of heat and phenol, acid-fast cells are not easily decolorized by an acid-alcohol wash and hence remain red cell wall of acid-fast bacteria Peptidoglycan + Outer Membrane-like Outer Membrane-like is composed of cord facter (or funicular facter),mycolic acid, polysaccharide(alternating ara and gal residues) and proteins. Cord facter is 6,6-dimycolytrehalose IV Reproduction of Bacteria Fission Binary fission Trinary fission Pelodictyo clathratiforme multiple fission Bdellovibrio (2) Budding Blastobacter Nitrobacter The procaryotic lack a membrane-delimited nucleus, but there are a few exceptions. The nuclear body of Gemmata obscuriglobus is bounded by two membranes. More work will be required to determine the functions of these membranes and how widespread this phenomenon is. Gemmata obscuriglobus Nuclear Body. An electron micrograph showing the membrane-bounded nuclear region . Note the central fibrillar area (F), the outer granular area (G), and the outer double-membrane structure (M). 6. Capsules, Slime Layers and S-layers Bacterial Capsules (a) Klebsiella pneumoniae, (b)Bacteroides glycocalyx Concept Capsule: Some bacteria have a layer of