Biodiversity of Microorganisms PDF

Animal Plant  Biodiversity of Microoorganisms Cell organization Procaryotes Eucaryotes Unicellular Unicellular Multicellular Archaeabac...

Animal Plant  Biodiversity of Microoorganisms Cell organization Procaryotes Eucaryotes Unicellular Unicellular Multicellular Archaeabac Fungi Fungi Eubacteria Protista teria (Yeast) (Mycetae) Mold Algae Protozoae Mushroom (Real fungi) Animal Plant 2  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Procaryotes (Unicellular) Bacteria and Archaea 3 Procaryote : cell structure  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Bacterial and Archaea Structure and Function prokaryotes differ from eukaryotes in size and simplicity – most lack internal membrane systems – term prokaryotes is becoming blurred – this text will use Bacteria and Archaea prokaryotes are divided into two taxa – Bacteria and Archaea 5  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Size, Shape, and Arrangement shape – cocci and rods most common – various others arrangement – determined by plane of division – determined by separation or not size - varies 6  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Shape and Arrangement-1 cocci (s., coccus) – spheres – diplococci (s., diplococcus) – pairs – streptococci – chains – staphylococci – grape-like clusters – tetrads – 4 cocci in a square – sarcinae – cubic configuration of 8 cocci 7  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Shape and Arrangement-2 bacilli (s., bacillus) – rods – coccobacilli – very short rods vibrios – resemble rods, comma shaped spirilla (s., spirillum) – rigid helices spirochetes – flexible helices 8  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.1 Cocci (Coccus) and Rods Shape Streptococcus agalactae Staphylococcus aureus Bacillus megaterium 9  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Shape and Arrangement-3 mycelium – network of long, multinucleate filaments pleomorphic – organisms that are variable in shape Archaea – pleomorphic, branched, flat, square, other unique shapes 10  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.2 Vibrio cholerae Rhodospirillum rubrum 11 Archea  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Differences of archea and bacteria https://opentextbc.ca/biology2eopens tax/chapter/structure-of- prokaryotes-bacteria-and-archaea/ 12  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Size smallest – 0.3 (Mycoplasma) average rod – 1.1 - 1.5 x 2 – 6 μm (E. coli) very large – 600 x 80 μm Epulopiscium fishelsoni 13  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.3 14  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.4 Epulopiscium fishelsoni – a giant bacteria 15  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Size – Shape Relationship important for nutrient uptake surface to volume ratio (S/V) small size may be protective mechanism from predation 16  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.5 17  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cell Organization Archaea and Bacteria Common Features : Structures & Functions Cell envelope – 3 layers Cytoplasm External structures 18  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Table 3.1 19  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.6 Morphology of a bacterial cell 20  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Bacterial Cell Envelope 1. Plasma membrane 2. Cell wall 3. Layers outside the cell wall 21  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1. Bacterial Plasma Membrane absolute requirement for all living organisms some bacteria also have internal membrane systems 22  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Plasma Membrane Functions encompasses the cytoplasm selectively permeable barrier interacts with external environment – receptors for detection of and response to chemicals in surroundings – transport systems – metabolic processes 23  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fluid Mosaic Model of Membrane Structure lipid bilayers with floating proteins – amphipathic lipids polar ends (hydrophilic – interact with water) non-polar tails (hydrophobic – insoluble in water) – membrane proteins 24  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fluid Mosaic Model of Membrane Structure Figure 3.7 25  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. The Asymmetry of Most Membrane Lipids Figure 3.8 26  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Membrane Proteins peripheral – loosely connected to membrane – easily removed integral – amphipathic – embedded within membrane – carry out important functions – may exist as microdomains 27  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Bacterial Lipids saturation levels of membrane lipids reflect the environmental conditions such as temperature bacterial membranes lack sterols but do contain sterol-like molecules, hopanoids – stabilize membrane – found in petroleum 28  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.9 Membrane Steroids and Hopanoids 29  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 2. Bacterial Cell Wall peptidoglycan (murein) – rigid structure that lies just outside the cell membrane – two types based on Gram stain gram positive – stain purple; thick peptidoglycan gram negative – stain pink or red; thin peptidoglycan and outer membrane 30  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.10 31  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cell Wall Functions maintains shape of the bacterium – almost all bacteria have one helps protect cell from osmotic lysis helps protect from toxic materials may contribute to pathogenicity 32  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Peptidoglycan Structure meshlike polymer of identical subunits forming long strands – two alternating sugars N-acetylglucosamine (NAG) N- acetylmuramic acid – alternating D- and L- amino acids 33  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.11 34  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Strands Are Crosslinked peptidoglycan strands have a helical shape peptidoglycan chains are crosslinked by peptides for strength – interbridges may form – peptidoglycan sacs – interconnected networks – various structures occur 35  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.12 36  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.13 37  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.14 Gram +ve cell wall 38  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.15 Diamino acids present in PDG meso- diaminopimelic acid L-lysine 39  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.16 Different forms of PDG structures in bacteria 40  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Gram-Positive Cell Walls composed primarily of peptidoglycan may also contain large amounts of teichoic acids (negatively charged) – help maintain cell envelop – protect from environmental substances – may bind to host cells some gram-positive bacteria have layer of proteins on surface of peptidoglycan 41  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Periplasmic Space of Gram + Bacteria lies between plasma membrane and cell wall and is smaller than that of gram-negative bacteria periplasm has relatively few proteins enzymes secreted by gram-positive bacteria are called exoenzymes – aid in degradation of large nutrients 42  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.17 43  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.18 44  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Gram-Negative Cell Walls more complex than gram positive consist of a thin layer of peptidoglycan surrounded by an outer membrane outer membrane composed of lipids, lipoproteins, and lipopolysaccharide (LPS) no teichoic acids 45  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Gram-Negative Cell Walls peptidoglycan is ~5-10% of cell wall weight periplasmic space differs from that in gram-positive cells – may constitute 20–40% of cell volume – many enzymes present in periplasm hydrolytic enzymes, transport proteins and other proteins 46  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Gram-Negative Cell Walls outer membrane lies outside the thin peptidoglycan layer Braun’s lipoproteins connect outer membrane to peptidoglycan other adhesion sites reported 47  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.19 48  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Lipopolysaccharides (LPSs) consists of three parts – lipid A – core polysaccharide – O side chain (O antigen) lipid A embedded in outer membrane core polysaccharide, O side chain extend out from the cell 49  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.20 50  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Importance of LPS contributes to negative charge on cell surface helps stabilize outer membrane structure may contribute to attachment to surfaces and biofilm formation creates a permeability barrier protection from host defenses (O antigen) can act as an endotoxin (lipid A) 51  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Gram-Negative Outer Membrane Permeability more permeable than plasma membrane due to presence of porin proteins and transporter proteins – porin proteins form channels through which small molecules (600–700 daltons) can pass 52  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.21 53  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mechanism of Gram Stain Reaction Gram stain reaction due to nature of cell wall shrinkage of the pores of peptidoglycan layer of gram-positive cells – constriction prevents loss of crystal violet during decolorization step thinner peptidoglycan layer and larger pores of gram-negative bacteria does not prevent loss of crystal violet 54  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Osmotic Protection hypotonic environments – solute concentration outside the cell is less than inside the cell – water moves into cell and cell swells – cell wall protects from lysis hypertonic environments – solute concentration outside the cell is greater than inside – water leaves the cell – plasmolysis occurs 55  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Evidence of Protective Nature of the Cell Wall lysozyme breaks the bond between N- acetyl glucosamine and N-acetylmuramic acid penicillin inhibits peptidoglycan synthesis if cells are treated with either of the above they will lyse if they are in a hypotonic solution 56  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Loss of Cell Wall May Survive in Isotonic Environments protoplasts spheroplasts Mycoplasma – does not produce a cell wall – plasma membrane more resistant to osmotic pressure 57  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.22 58  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 3. Components Outside of the Cell Wall outermost layer in the cell envelope glycocalyx – capsules and slime layers – S layers aid in attachment to solid surfaces – e.g., biofilms in plants and animals 59  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Capsules usually composed of polysaccharides well organized and not easily removed from cell visible in light microscope protective advantages – resistant to phagocytosis – protect from dessication – exclude viruses and detergents 60  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Slime Layers similar to capsules except diffuse, unorganized and easily removed slime may aid in motility 61  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.23 62  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.24 63  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. S Layers regularly structured layers of protein or glycoprotein that self- assemble – in gram-negative bacteria the S layer adheres to outer membrane – in gram-positive bacteria it is associated with the peptidoglycan surface 64  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.25 65  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. S Layer Functions protect from ion and pH fluctuations, osmotic stress, enzymes, and predation maintains shape and rigidity promotes adhesion to surfaces protects from host defenses potential use in nanotechnology – S layer spontaneously associates 66  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Industrial products from LPS Home work for discussion: 1. Give some examples of LPS or other outer cell wall components which are produced industrially. 2. Give examples of products from archea 67  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Archaeal Cell Envelopes differ from bacterial envelopes in the molecular makeup and organization – S layer may be only component outside plasma membrane – some lack cell wall – capsules and slime layers are rare 68  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Archaeal Membranes composed of unique lipids – isoprene units (five carbon, branched) – ether linkages rather than ester linkages to glycerol some have a monolayer structure instead of a bilayer structure 69  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.26 70  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.27 71  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Archaeal Cell Walls Differ from Bacterial Cell Walls lack peptidoglycan most common cell wall is S layer may have protein sheath external to S layer S layer may be outside membrane and separated by pseudomurein pseudomurein may be outermost layer – similar to gram-positive microorganisms 72  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.28 73  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.29 74  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Bacterial and Archaeal Cytoplasmic Structures Cytoskeleton Intracytoplasmic membranes Inclusions Ribosomes Nucleoid and plasmids 75  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Protoplast and Cytoplasm protoplast is plasma membrane and everything within cytoplasm - material bounded by the plasmid membrane 76  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. The Cytoskeleton homologs of all 3 eukaryotic cytoskeletal elements have been identified in bacteria and 2 in archaea functions are similar as in eukaryotes – Role in cell division, protein localization, and determination of cell shape 77  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Table 3.2 78  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Best Studied Examples FtsZ – many bacteria and archaea – forms ring during septum formation in cell division MreB – many rods, some archaea – maintains shape by positioning peptidoglycan synthesis machinery CreS – rare, maintains curve shape 79  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.30 80  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Intracytoplasmic Membranes plasma membrane infoldings – observed in many photosynthetic bacteria analogous to thylakoids of chloroplasts reactions centers for ATP formation – observed in many bacteria with high respiratory activity anammoxosome in Planctomycetes – organelle – site of anaerobic ammonia oxidation 81  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.31 82  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.32 83  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Inclusions granules of organic or inorganic material that are stockpiled by the cell for future use some are enclosed by a single-layered membrane – membranes vary in composition – some made of proteins; others contain lipids – may be referred to as microcompartments 84  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Storage Inclusions storage of nutrients, metabolic end products, energy, building blocks glycogen storage carbon storage – poly-β-hydroxybutyrate (PHB) phosphate - Polyphosphate (Volutin) amino acids - cyanophycin granules 85  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.33 86  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.34 87  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Microcompartments not bound by membranes but compartmentalized for a specific function carboxysomes - CO2 fixing bacteria – contain the enzyme ribulose-1,5,- bisphosphate carboxylase (Rubisco), enzyme used for CO2 fixation 88  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.35 89  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Other Inclusions gas vacuoles – found in aquatic, photosynthetic bacteria and archaea – provide buoyancy in gas vesicles magnetosomes – found in aquatic bacteria – magnetite particles for orientation in Earth’s magnetic field – cytoskeletal protein MamK helps form magnetosome chain 90  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.36 91  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.37 92  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Ribosomes complex structures – consisting of protein and RNA – sites of protein synthesis entire ribosome – bacterial and archaea ribosome = 70S – eukaryotic (80S) S = Svedburg unit bacterial and archaeal ribosomal RNA – 16S small subunit – 23S and 5S in large subunit – archaea has additional 5.8S (also seen in eukaryotic large subunit) proteins vary – archaea more similar to eukarya than to bacteria 93  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.38 94  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. The Nucleoid irregularly shaped region in bacteria and archaea usually not membrane bound (few exceptions) location of chromosome and associated proteins usually 1 – a closed circular, double-stranded DNA molecule supercoiling and nucleoid proteins (HU) probably aid in folding – nucleoid proteins differ from histones 95  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.39 96  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Plasmids extrachromosomal DNA – found in bacteria, archaea, some fungi – usually small, closed circular DNA molecules exist and replicate independently of chromosome – episomes – may integrate into chromosome contain few genes that are non-essential – confer selective advantage to host (e.g., drug resistance) 97  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Plasmids may exist in many copies in cell inherited stably during cell division curing is the loss of a plasmid classification of plasmids based on mode of existence, spread, and function see Table 3.3 98  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Table 3.3 99  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. External Structures extend beyond the cell envelop in bacteria and archaea function – protection, attachment to surfaces, horizontal gene transfer, cell movement pili and fimbriae flagella 100  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Pili and Fimbriae fimbriae (s., fimbria); pili (s., pillus) – short, thin, hairlike, proteinaceous appendages (up to 1,000/cell) – mediate attachment to surfaces – some (type IV fimbriae) required for motility or DNA uptake sex pili (s., pilus) – similar to fimbriae except longer, thicker, and less numerous (1-10/cell) – genes for formation found on plasmids – required for conjugation 101  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.40 102  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Flagella threadlike, locomotor appendages extending outward from plasma membrane and cell wall functions – motility and swarming behavior – attachment to surfaces – may be virulence factors 103  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Bacterial Flagella thin, rigid protein structures that cannot be observed with bright-field microscope unless specially stained ultrastructure composed of three parts pattern of flagellation varies 104  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Patterns of Flagella Distribution monotrichous – one flagellum polar flagellum – flagellum at end of cell amphitrichous – one flagellum at each end of cell lophotrichous – cluster of flagella at one or both ends peritrichous – spread over entire surface of cell 105  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.41 106  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Three Parts of Flagella filament – extends from cell surface to the tip – hollow, rigid cylinder – composed of the protein flagellin – some bacteria have a sheath around filament hook – links filament to basal body basal body – series of rings that drive flagellar motor 107  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.42 108  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Flagellar Synthesis complex process involving many genes and gene products new molecules of flagellin are transported through the hollow filament using Type III-like secretion system filament subunits self-assemble with help of filament cap growth is from tip, not base 109  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.43 110  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Differences of Archaeal Flagella flagella thinner more than one type of flagellin protein flagellum are not hollow hook and basal body difficult to distinguish more related to Type IV secretions systems growth occurs at the base, not the end 111  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.44 112  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Motility Flagellar movement Spirochete motility Twitching motility Gliding motility 113  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Motility Bacteria and Archaea have directed movement chemotaxis – move toward chemical attractants such as nutrients, away from harmful substances move in response to temperature, light, oxygen, osmotic pressure, and gravity 114  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Bacterial Flagellar Movement flagellum rotates like a propeller – very rapid rotation up to 1100 revolutions/sec – in general, counterclockwise (CCW) rotation causes forward motion (run) – in general, clockwise rotation (CW) disrupts run causing cell to stop and tumble 115  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.45 116  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mechanism of Flagellar Movement flagellum is 2 part motor producing torque rotor – C (FliG protein) ring and MS ring turn and interact with stator stator - Mot A and Mot B proteins – form channel through plasma membrane – protons move through Mot A and Mot B channels and produce energy through proton motive force – torque powers rotation of the basal body and filament 117  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.46 118  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Spirochete Motility multiple flagella form axial fibril which winds around the cell flagella remain in periplasmic space inside outer sheath corkscrew shape exhibits flexing and spinning movements 119  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.47 120  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Twitching and Gliding Motility may involve Type IV pili and slime twitching – pili at ends of cell – short, intermittent, jerky motions – cells are in contact with each other and surface gliding – smooth movements 121  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Myxococcus xanthus Movement social – Type IV pili move together in large groups of cells adventurous (Gliding) – alime released moves cell forward – adhesion complexes move in track provided by cytoskeleton 122  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.48 123  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chemotaxis movement toward a chemical attractant or away from a chemical repellent changing concentrations of chemical attractants and chemical repellents bind chemoreceptors of chemosensing system 124  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.49 125  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chemotaxis in presence of attractant (b) tumbling frequency is intermittently reduced and runs in direction of attractant are longer behavior of bacterium is altered by temporal concentration of chemical chemotaxis away from repellent involves similar but opposite responses 126  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.50 127  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. The Bacterial Endospore complex, dormant structure formed by some bacteria various locations within the cell resistant to numerous environmental conditions – heat – radiation – chemicals – desiccation 128  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.51 129  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Endospore Structure spore surrounded by thin covering called exosporium thick layers of protein form the spore coat cortex, beneath the coat, thick peptidoglycan core has nucleoid and ribosomes 130  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.52 131  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. What Makes an Endospore so Resistant? calcium (complexed with dipicolinic acid) small, acid-soluble, DNA-binding proteins (SASPs) dehydrated core spore coat and exosporium protect 132  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Sporulation process of endospore formation occurs in a hours (up to 10 hours) normally commences when growth ceases because of lack of nutrients complex multistage process 133  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 3.53 134  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Germination transformation Figure 3.54 of endospore into vegetative cell complex, multistage process 135  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Formation of Vegetative Cell activation – prepares spores for germination – often results from treatments like heating germination – environmental nutrients are detected – spore swelling and rupture of absorption of spore coat – loss of resistance – increased metabolic activity outgrowth - emergence of vegetative cell 136