Bacteria Cell shapes Cell group arrangements Bacterial cell
advertisement
Bacteriology - Exam 1 1 Bacteria size and organization Smallest living single celled organisms 0.2-2.0 microns 0.000002 - 0.000002 meters Chlamydia and Rickettsia Prokaryotic organization Nucleoid – chromosome with no membrane Few and simple internal organelles 2 Size scale 3 Bacteria on human cell photo 4 E. coli on a surgical needle SEM photo 5 Bacteria Cell shapes Cocci Coccobacilli Bacilli Curved or curled Vibrios Spirilla Spirochete Mycoplasma 6 Bacteria cell shapes photos 7 Mycoplasma pneumoniae AFB photo 8 Mycoplasma cells covering a host cell 9 Cell group arrangements Chains Diplo Strepto Filamentous – long branching chains Nocardia, Actinomyces Clusters Tetrads Sarcinae Staphylo Identification Colored stains 10 Arrangements of cocci 11 Cocci arrangement photos 12 Bacterial cell arrangements image BIO 205 - Spring 2007 1 Bacteriology - Exam 1 13 Filamentous bacteria photo 14 Filamentous bacteria SEM photo 15 Outer cell layers image 16 Glycocalyx – outer most layer Composition Polysaccharide gel Observed by stains Forms Slime layer - loose no shape Klebsiella pneumoniae Capsule – tighter, rigid Streptococcus pneumoniae Haemophilus influenzae Functions Protection Adherence Virulence/pathogenicity 17 Glycocalyx types image 18 Glycocalyx photos 19 Streptococcus glycocalyx 20 Glycocalyx and pathogenicity 21 Gram positive cell wall 1 layer Multiple-layers of Peptidoglycan inside the glycocalyx Wall Outside of the Plasma membrane Identification Gram stain – crystal violet 22 Gram positive cell wall image 23 Isolated Bacterial Cell Wall photo 24 Gram negative cell wall 2 layers Outer Membrane with a single peptidoglycan layer under this membrane Toxic wall compounds in outer membrane Endotoxins LPS – lipopolysaccharide Wall Outside of the Plasma membrane Identification Gram stain - safranin 25 Gram negative cell wall image 26 G + cell wall BIO 205 - Spring 2007 G - cell wall 2 Bacteriology - Exam 1 27 Gram stain picture 28 Acid fast cell wall 1 layer Wax integrated with peptidoglycan Similar to G+ cell walls Plasma membrane inside of wall Wax content varies Mycoplasmas>Mycobacteria>Nocardia Mycoplasmas almost pure wax wall Nocardia mostly peptidoglycan AFB qualities Plastic and durable Resists WBC’s and disinfectants Slow growth Identification Acid Fast Stain - carbolfuschin 29 Acid fast stain of sputum 30 Extracellular and periplasmic spaces Space between cell wall and plasma membrane Enzymes, nutrients, wastes 31 Periplasmic space in G- bacteria 32 Plasma membrane 33 Plasma membrane image 34 Plasma membrane 35 Plasma membrane 36 Flagella For movement Protein filament complex Rotational movement Example bacteria Escherichia, Chlamydia, Proteus Axial filaments - Treponema Flagella filaments attached along side of cell Cell rotates Identification Colored stains Antibodies 37 Flagella structure image 38 Bacteria flagella photos 39 Flagella stain photo 40 Flagella actions BIO 205 - Spring 2007 3 Bacteriology - Exam 1 41 Axial filament - Treponema 42 Pili Composition Protein filaments Shorter than flagella Functions Adherence pili - to host Conjugation or sex pili Gene exchange between bacteria Example bacteria E. coli, Streptococcus, most pathogenic bacteria 43 Bacteria with pili photo 44 Bacterial conjugation photo 45 Ligands Also called Fimbrae Small membrane attachment proteins Adherence to host receptors High specificity to host cell receptors Toxins – some damage host cells 46 Bacterial ligand on host receptors image 47 Internal storage granules Granules usually store nutrients Organic lipids, carbohydrates Inorganic minerals, salts 48 Storage granules photos 49 Endospores Endospore qualities Resistant dormant form no metabolic activity Dense keratin outer wall Sporulation -1 spore formed by 1 cell Spores formed in stress conditions Germination - 1 cell formed by 1 spore Example bacteria Clostridium, Bacillus, Chlamydia 50 Bacterial endospore formation image 51 Bacterial endospore photos BIO 205 - Spring 2007 4 Bacteriology - Exam 1 52 Bacterial genomic chromosome Nucleoid Single chromosome Circular Supercoiled DNA composition 53 Bacterial genomic nucleoid photo 54 E. coli chromosome extracted photo 55 Plasmid chromosome Secondary or extrachromosomal DNA Source Bacterial or viral transfer Transposons Intergrative DNA May be attached to genomic DNA 56 Cell and viral chromosomes image 57 Plasmid and genomic chromosome image 58 Genetic Identification Specific genes or fragments of DNA used for identification Genes or fragments must be specific to the organism 1. DNA probes Specific DNA probe attaches to exact match DNA fragment 2. Gene fingerprinting – RFLP Specific DNA fragment separated out of chromosome for I.D. Separated and identified 3. DNA microarray 59 DNA probe method image 1 60 DNA probe method image 2 61 RFLP – DNA fingerprinting 62 Microarray analysis 63 Immunological stain identification High specificity to anatomical feature Specific antibody developed for a specific target Antibody bonds to specific structures Antibody has a fluorescent or colored chemical attached to make it visible 64 Fluorescent antibody stain image 65 Fluorescent antibody stain photos BIO 205 - Spring 2007 5 Bacteriology - Exam 1 66 Bacterial Reproduction Binary fission Chromosomes replicate Cell expands and divides Rate – from 20 minutes to several days 67 Binary fission image 68 Bacterial chromosome replication image 69 Plaque or biofilm Layer or film produced by living organisms Cells within a plaque may be living or dead Bacterial plaque Large number of cells attached by glycocalyx Colony or glycocalyx matrix Plaques of even small sizes can produce life threatening responses 70 Bacterial colony close up photo 71 Coliform colonies on agar photo 72 Biofilm on tooth 73 Dental plaque image 74 Top surface view of a Bacterial biofilm 75 Taxonomic Levels Kingdom - Prokaryotae Division - Gracilicutes Class - Scotobacteria Order - Enterobacterales Family - Enterobacteraceae Genus - Escherichia Species - coli Strain – 0157:H7 E. coli 0157:H7 76 Taxonomic Levels image 77 Medically important bacterial groups Group criteria Cell wall composition Oxygen requirements Shape 78 Gram negative anaerobes Spirochetes Treponema BIO 205 - Spring 2007 6 Bacteriology - Exam 1 Borrelia Bacilli Bacteroides Fusobacterium 79 Gram negative aerobes Pseudomonads Vibrios – cholera Camphylobacter - spirilla Legionella Pasteurella Hemophilus Neisseria - coccobacilli Smallest bacteria Chlamydia – spore former Rickettsia - bacilli 80 Gram negative aerobic, bacilli Coliform or enteric Enterobacter Escherichia Salmonella Klebsiella Proteus Serratia Shigella 81 Gram positive, aerobic cocci Streptoccocus Staphylococcus Enterococcus Micrococcus 82 Acid Fast, aerobic bacilli Cell wall has wax and peptidoglycan Nocardia - small amount of wax Corynebacteria Mycobacteria Mycoplasmas - all wax wall, very small 83 Gram positive Spore forming anaerobes Clostridium Chlamydia BIO 205 - Spring 2007 7
