上海交通大学：《医学微生物》课程教学资源（PPT课件讲稿）英文版 chaper 2 Bacterial Morphology and Structure

Bacterial Morphology and Structure Xiao-Kui Guo phD http://basic.shsmu.edu.cn/pa / indexes

Bacterial Morphology and Structure Xiao-Kui Guo PhD http://basic.shsmu.edu.cn/passw/micro2/index.asp

SIZE OF BACTERIA Coccus ● Unit for measurement Micron or micrometer, um ③ Ium=10-3mm ●Size Varies with kinds of bacteria. and Streptobacillus also related to their age and external environment Staphylococcus Cocco-baciilus Light Human Eye ectron Microscope Microscope Microscopic Application Units and I meter or symbols 1,000 mm 100 mm 10 mm I mm 100 um 10 um I um 100 nm 10 nm I nm Fraction of 100 10. 103 106 107 10 109 Cocc sphere, 1u m e Bacilli: rods, 0.5-1 um in width-3 um in length e Spiral bacteria: 1-3 um in length and 0.3-0.6 um in width

SIZE OF BACTERIA ⚫ Unit for measurement : Micron or micrometer,μm: 1μm=10-3mm ⚫ Size: Varies with kinds of bacteria, and also related to their age and external environment. ⚫ Cocci: sphere, 1μm ⚫ Bacilli: rods , 0.5-1 μm in width -3 μm in length ⚫ Spiral bacteria: 1~3 μm in length and 0.3-0.6 μm in width

Structure of bacteria Essential structures Flagellum cell wal|细胞壁 Granular inclusion cell membrane细胞膜 Cytoplasm细胞质 nuclear materia|核质 membrane(if Cytoplasmic membrane Nucleoli Mesosome Pili 专 Particular structures capsule荚膜 fagella鞭毛 pili菌毛 spore芽胞

Structure of Bacteria Particular structures capsule 荚膜 flagella 鞭毛 pili 菌毛 spore 芽胞 Essential structures cell wall 细胞壁 cell membrane 细胞膜 Cytoplasm 细胞质 nuclear material 核质

1884: Christian Gram: First publication for the Gram stain method) Editor's note: I would like to testify that I have found the Gram method to be one of the best and for many cases the best method which I have ever used for staining Schizomycetes Flagellum Cell membrane ucleoid Cell wall Gram-positiYe Gram-negative outer membrane ●● Gram+ membrane toplasmcytoplasm Pili Gram periplasmic G ranule peptidoglycan Capsule Cell(inner)/membrane I Outer membrane Gram, C. 1884. Ueber die isolite Farbung Ribosomes der Schizomycete in SchnittAund Cell wall Trockenpraparaten. Fortschritte der Medicin, Vol 2, pages 185-189

Gram + Gram - Cell wall Cell (inner) membrane Outer membrane Ribosomes Granule Cell wall Cell membrane Nucleoid Capsule Flagellum Pili Gram, C. 1884. Ueber die isolirte Farbung der Schizomyceten in SchnittÄund Trockenpraparaten. Fortschritte der Medicin, Vol. 2, pages 185-189. 1884: Christian Gram: First publication for the Gram stain method) Editor's note: I would like to testify that I have found the Gram method to be one of the best and for many cases the best method which I have ever used for staining Schizomycetes

Cell wall Situation outmost portion membrane Cytoplasmic membrane Murein wall 15-30nm in thickness. 10% 25% of di weight a-n Gram-positive envelope envelope Gram Positive cell Envelope Gram Negative Cell Envelope Lipoteichoic Peptidogbycan-teichoic acid Lipopolysaccharide nodaPoBodastissGtng 合号98召暴 Peptidoglycan 880009809000800939310

Cell wall ⚫ Situation: outmost portion. 15-30nm in thickness, 10%- 25% of dry weight

Cell wall. Common peptidoglycan ayer o A backbone of N-acetyl glucosamine and N-acetylmuramic acid: Both discovered in grampositive and Gram negative bacteria. o A set of identical tetrapeptide side chain attached to N-acetyl-muramic acid: different components and binding modes in gram positive and Gram negative bacteria o A set ofidentical peptide cross bridges: only in grampositive bacteria NAM NAG CH,OH CH2OH CHOH H H OH OH H1C、点NHH H,C C-H O=C C=9..H3 Gly-Gly-Gly-Gly-Gly ly-Gly-Gly-Gly-Gly

Cell wall :Common peptidoglycan layer ⚫ A backbone of N-acetyl glucosamine and N-acetylmuramic acid: Both discovered in Grampositive and Gramnegative bacteria. ⚫ A set of identical tetrapeptide side chain attached to N-acetyl-muramic acid: different components and binding modes in Gram positive and Gram negative bacteria. ⚫ A set of identical peptide cross bridges: only in Gram positive bacteria

Staphylococcus aureus peptidoglycan E coli peptidoglycan The Effect of Lysozyme on the Cell Wall

Special components of Gram positive cell wa∥ Teichoic acid -associaed SPA/MPOTEIN

Special components of Gram positive cell wall Teichoic acid SPA / M POTEIN

Lipopolysaccharide Special components of Ketodeoxyoctonic acid Gram negative cell wall Glucosamine disaccharide Beta hydroxy fatty acids Madigan pPRotein( ipid A (LPS) Gram-negative Periplasm

Special components of Gram negative cell wall

Functions of cell wall o Maintaining the cell's characteristic shape -the rigid wall compensates for the flexibility of the phospholipid membrane and keeps the cell from assuming a spherical shape o Countering the effects of osmotic pressure o Providing attachment sites for bacteriophages o Providing a rigid platform for sur face appendages flagella, fimbriae, and pili all emanate from the wall and extend beyond it o Play an essential role in cell division o Be the sites of major antigenic determinants of the cell surface。 o Resistance of antibiotics

Functions of Cell Wall ⚫ Maintaining the cell's characteristic shape- the rigid wall compensates for the flexibility of the phospholipid membrane and keeps the cell from assuming a spherical shape ⚫ Countering the effects of osmotic pressure ⚫ Providing attachment sites for bacteriophages ⚫ Providing a rigid platform for surface appendages￾flagella, fimbriae, and pili all emanate from the wall and extend beyond it ⚫ Play an essential role in cell division ⚫ Be the sites of major antigenic determinants of the cell surface。 ⚫ Resistance of Antibiotics