1. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Brock Biology of Microorganisms Twelfth Edition Madigan / Martinko Dunlap / Clark Bacteria : Gram-Positive and Other Bacteria Chapter 16 Lectures by Buchan & LeCleir

2. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings I. Overview of Gram-Positive and Other Bacteria  Bacteria has many other phyla, including  Gram-positive bacteria  Large group of mostly chemoorganotrophic  Cyanobacteria  Oxygeneic phototrophs that have evolutionary roots near those of gram- positive bacteria  Phylogenetically early-branching phyla  Such as Aquifex  Other morphologically distinct groups

3. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings II. Gram-Positive Bacteria and Actinobacteria  16.1Nonsporulating Gram-Positive Bacteria  16.2Endospore-Forming Gram-Positive Bacteria  16.3Cell-Wall-Less Gram-Positive Bacteria: The Mycoplasmas  16.4Actinobacteria: Coryneform and Propionic Acid Bacteria  16.5Actinobacteria: Mycobacterium  16.6Filamentous Actinobacteria: Streptomyces and Relatives

4. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings II. Gram-Positive Bacteria and Actinobacteria  Gram-positive bacteria are a large and diverse group  Previously divided into two groups  High G+C (Actinobacteria), >50% G+C  Low G+C <50% G+C

5. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.1 Nonsporulating Gram-Positive Bacteria  Key genera: Staphylococcus, Micrococcus, Streptococcus, Lactobacillus, Sarcina  Staphylococcus and Micrococcus  Aerobic, cocci  Resistant to reduced water potential  Tolerate high salt  Many species are pigmented  Staphylococcus aureus

6. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.1 Nonsporulating Gram-Positive Bacteria  Sarcina  Obligate anaerobes  Extremely acid tolerant  Can inhabit and grow in stomachs of monogastric animals

7. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.1 Nonsporulating Gram-Positive Bacteria  Streptococcus  Homofermentative  Play important roles in production of buttermilk, silage, and other products  Some species are pathogenic  Lactococcus: genera of dairy significance  Enterococcus: genera of fecal origin

8. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.1 Nonsporulating Gram-Positive Bacteria  Lactobacillus  Rod-shaped  Common in dairy products  Resistant to acidic conditions  Grow in pH as low as 4

9. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.1 Nonsporulating Gram-Positive Bacteria  Listeria  Gram-positive coccobacilli  Form chains 3–5 cells long  Require full oxic or microoxic conditions for growth

10. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Distinguishing Features of Major Gram-Positive Cocci

11. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Staphylococcus aureus Figure 16.1

12. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Sarcina Figure 16.2

13. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Differentiation of the Principal Genera of Lactic Acid Bacteria

14. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Gram-Positive Cocci Figure 16.3 Lactococcus lactis Streptococcus sp.

15. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Differential Characteristics Complete hemolysis (β-hemolysis): due to hemolysins (e.g. streptolysin O or S). Antigenic groups are divided based on the presence of specific carbohydrate antigens.

16. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Lactobacillus species Figure 16.4 Lactobacillus acidophilus Lactobacillus brevis Lactobacillus delbrueckii

17. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.2 Endospore-Forming Gram-Positive Bacteria  Key Genera: Bacillus, Clostridium, Sporosarcina, Heliobacterium  Distinguished on the basis of cell morphology, shape and cellular position of endospore  Generally found in soils  Endospores are advantageous for soil microorganisms

18. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Major Genera of Endospore-Forming Bacteria

19. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.2 Endospore-Forming Gram-Positive Bacteria  Bacillus and Paenibacillus  Many produce extracellular hydrolytic enzymes that break down polymers  Many bacilli produce antibiotics  Paenibacillus popilliae and Bacillus thuringiensis produce insect larvicides

20. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Characteristics of Representative Species of Bacilli

21. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Toxic Parasporal Crystal in Bacillus thuringiensis Figure 16.6

22. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.2 Endospore-Forming Gram-Positive Bacteria  Clostridium  Lack a respiratory chain, anaerobic  Some Clostridia perform Stickland reactions  Metabolism of pair of amino acids  Mainly found in anaerobic pockets in the soil  Also live in mammalian intestinal tract  Some are pathogenic; cause diseases such as botulism, tetanus, and gas gangrene

23. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Characteristics of Some Groups of Clostridia

24. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Clostridium Species and Endospore Location Figure 16.5 Clostridium cadaveris Terminal endospores Clostridium sporogenes Subterminal endospores Clostridium bifermentans Central endspores

25. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.2 Endospore-Forming Gram-Positive Bacteria  Sporosarcina  Unique among endospore formers because cells are cocci instead of rods  Strictly aerobic, spherical cells  Common in soils

26. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Sporsarcina ureae Figure 16.7

27. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.2 Endospore-Forming Gram-Positive Bacteria  Heliobacteria  Phototrophic gram-positive bacteria  Anoxygenic phototrophs  Produce bacteriochlorophyll g  Strict anaerobes  Reside in soils and also in highly alkaline environments (i.e., soda lakes and alkaline soils)  Have nitrogen-fixation capabilities

28. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Cells and Endospores of Heliobacteria Figure 16.8 Heliobacillus mobilis Heliophilum fasciatum Heliobacterium gestii

29. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.3 Cell-Wall-Less Gram-Positive Bacteria: Mycoplasmas  Key genera: Mycoplasma, Spiroplasma  Lack cell walls  Some of the smallest organisms capable of autonomous growth  Parasites that inhabit animal and plant hosts  Key components of peptidoglycan are missing - Muramic acid and diaminopimelic acid  Mycoplasma cells are pleomorphic  Cells may be cocci or filaments of various lengths

30. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Major Characteristics of Mycoplasmas

31. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.3 Cell-Wall-Less Gram-Positive Bacteria: Mycoplasmas  Spiroplasma  Helical or spiral-shaped wall-less cells  Rotary screw motility  Isolated from ticks, hemolymph and gut of insects, vascular plant fluids, and insects that feed on the fluids

32. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Mycoplasma mycoides Figure 16.9

33. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings “Fried Egg” Appearance of Mycoplasma Colonies on Agar Figure 16.10 Dense central core

34. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Spiroplasma from Hemolymph of D. pseudoobscura Figure 16.11 “Sex ratio” spiroplasma

35. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.4 Actinobacteria: Coryneform & Propionic Acid Bacteria  Key genera: Corynebacterium, Arthrobacter, Propionibacterium  Actinobacteria form their own phylum - High G+C gram-positive bacteria  Over 30 taxonomic families  Rod to filamentous, usually aerobic  Mostly harmless commensals (Mycobacterium are notable exceptions)  Valuable for antibiotics and certain fermented dairy products

36. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.4 Actinobacteria: Coryneform & Propionic Acid Bacteria  Corynebacterium  Gram-positive, aerobic, non-motile, rod-shaped  Form club-shaped, irregular-shaped, or V-shaped cell arrangements  Extremely diverse  Arthrobacter  Primarily soil organisms  Remarkably resistant to dessication and starvation

37. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.4 Actinobacteria: Coryneform & Propionic Acid Bacteria  Propionic Acid Bacteria  First discovered in Swiss cheese  Gram-positive anaerobes  Have metabolic strategy called secondary fermentation  Obtain energy from fermentation products produced by other bacteria - Propionibacterium: lactic acid - Propionigenium: succinate

38. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Snapping Division in Arthrobacter crystallopoietes Figure 16.12

39. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Cell Division in Arthrobacter crystallopoietes Figure 16.13

40. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Stages in Life Cycle of Arthrobacter globiformis Figure 6.14 Rods to coccoid forms

41. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.5 Actinobacteria: Mycobacterium  Mycobacterium  Rod-shaped organisms, exhibit acid-fastness  First discovered by Robert Koch  Not readily stained by Gram stain because of high surface lipid content  Cells are somewhat pleomorphic  Separated into two groups: slow and fast growers  Classified into three groups based on pigmentation

42. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Acid-Fast Stain (Ziehl-Neelsen Stain) Figure 16.15 Basic fuchsin and phenol – heating – washing (DW) – acid alcohol –wash – methylene blue - Acid-fast organism: red - Non-acid-fast organism: blue

43. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Characteristic Colony Morphology of Mycobacteria Figure 16.16 M. tuberculosis colony Colony of virulent M. tuberculosis at an early stage M. avium colonies

44. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Structure of Cord Factor, a Mycobacterial Glycolipid Figure 16.17 6,6’-dimycolyltrehalose

45. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.6 Filamentous Actinobacteria: Streptomyces & Others  Key genera: Streptomyces, Actinomyces  Filamentous, gram-positive bacteria  Produce mycelium analogous to mycelium of filamentous fungi  Over 500 species of Streptomyces are recognized  Streptomyces spores are called conidia (in the aerial mycelium sporophores)  Primarily soil microorganisms, responsible for earthy odor of soil (geosmins)  Strict aerobes that produce many extracellular enzymes

46. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.6 Filamentous Actinobacteria: Streptomyces & Others  Streptomyces  50% of all isolated Streptomyces produce antibiotics  Over 500 distinct antibiotics produced by Streptomyces  Some produce more than one antibiotic  Genomes are typically quite large (8 Mbp and larger)  Knowledge of the ecology of Streptomyces remains poor

47. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Nocardia Figure 16.18

48. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Spore-Bearing Structures of Actinomycetes Figure 16.19 Streptomyces sp.

49. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Spore Formation in Streptomyces Figure 16.20

50. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Colonies of Streptomyces Figure 16.22

51. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Antibiotics from Streptomyces Figure 16.23 Streptomyces coelicolor and red-colored antibiotic undecylprodigiosin

52. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Some Common Antibiotics Synthesized by Streptomyces

53. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings III. Cyanobacteria and Prochlorophytes  16.7Cyanobacteria  16.8Prochlorophytes

54. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.7 Cyanobacteria  Key genera: Synechococcus, Oscillatoria, Nostoc  Oxygenic phototrophs  Impressive morphological diversity  Unicellular (divide by binary fission)  Unicellular (divide by multiple fission)  Filamentous (with heterocysts)  Filamentous (nonheterocystous)  Branching filamentous

55. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Genera and Grouping of Cyanobacteria

56. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Cyanobacteria : the Five Major Morphologies Figure 16.24a-c GloeotheceDermocarpaOscillatoria

57. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Cyanobacteria : the Five Major Morphologies Figure 16.24d-e Anabaena Fischerella

58. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.7 Cyanobacteria  Most species are obligate phototrophs - chlorophyll a and phycobilins ( Red algae also has chlorophyll a and phycobilin)  Many cyanobacteria produce potent neurotoxins  Widely distributed in terrestrial, freshwater, and marine habitats  Can be phototrophic component of lichens  Often form extensive crusts in desert soils

59. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Thylakoids in Cyanobacteria Figure 16.25 Synecoccus lividus

60. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Thylakoids in Cyanobacteria Figure 16.25

61. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.7 Cyanobacteria  Gas vesicles are found in many cyanobacteria  Help maintain buoyancy  Keep cell in water column where there is light  Heterocysts are rounded, enlarged cells  Anoxic environment inside heterocyst  Site for nitrogen fixation  Nitrogenase is sensitive to oxygen  Lack photosystem II and low in phycobilin pigments  Unable to fix CO 2

62. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.7 Cyanobacteria

63. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.7 Cyanobacteria  Cyanophycin  A copolymer of Asp and Arg  Nnitrogen storage product  Also an energy reserve - arginine dihydrolase system (arginine deiminase, ornithine carbamoyl transferase, and carbamate kinase) * Arg + H 2 O → citrulline + NH 3 citrulline + Pi → ornithine + carbomoyl phosphate carbomoyl phosphate + ADP → ATP + NH 3 + CO 2 (Net: Arg + ADP + Pi + H 2 O → ornithine +2NH 3 + CO 2 + ATP)  Many cyanobacteria display gliding motility

64. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.7 Cyanobacteria

65. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.8 Prochlorophytes  Key genera: Prochloron, Prochlorothrix, and Prochlorococcus  Oxygenic phototrophs  Prochloron was first prochlorophyte discovered - contains chlorophylls a and b - No phycobilins

66. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Electron Micrograph of the Prochlorophyte Prochloron Figure 16.28 Prochloron

67. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.8 Prochlorophytes  Prochlorothrix  Have chlorophylls a and b and lacks phycobilins  Prochlorococcus  Found in euphotic zone of the open oceans  The smallest and most abundant photosynthetic microorganism on Earth (?)  0.5–0.8 micrometers in diameter  10 5 Prochlorococcus per milliliter of seawater  Produce divinyl chlorophyll a (not the true chlorophyll a), chlorophyll b, and alpha-carotene

68. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Filamentous Prochlorothrix and Acaryochloris Figure 16.29 Phase Contrast Electron Micrograph of Thin Section Acaryochlorus, Thin Section Prochlorothrix Contain chlorophyll a and b

69. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings IV. Chlamydia  16.9The Chlamydia

70. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.9 The Chlamydia  Key genera: Chlamydia, Chlamydophila  Obligately parasitic with poor metabolic capacities  One of the simplest biochemical capacities of all known bacteria  Currently a cause of one of the leading sexually transmitted diseases

71. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.9 The Chlamydia

72. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.9 The Chlamydia

73. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Chlamydia Figure 16.30 Chlamydia psittaci

74. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings The Infection Cycle of Chlamydia Figure 16.31a

75. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings The Infection Cycle of Chlamydia Figure 16.31b Human Chlamydial Infection

76. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings V. Planctomyces/ Pirellula  16.10 Planctomyces/Pirellula: A phylogenetically unique stalked bacterium

77. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.10 Planctomyces: A Phylogenetically Unique Bacterium  Key genera: Planctomyces, Pirellula, Gemmata  Planctomyces is a budding bacterium  Facultative aerobic chemoorganotroph  Stalked  Primarily aquatic  Extensive cell compartmentalization including a membrane-enclosed nuclear structure

78. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Planctomyces maris Figure 16.32

79. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Gemmata : a Nucleated Bacterium Figure 16.33

80. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings VI. The Verrucomicrobia  16.11 Verrucomicrobium and Prosthecobacter

81. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.11 Verrucomicrobium and Prosthecobacter  Key genera: Verrucomicrobium  Form cytoplasmic extensions called prosthecae  Produce two prosthecae per cell  Aerobic to facultative aerobic bacteria  Inhabit freshwater and marine environments as well as forest and agricultural soils

82. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Verrucomicrobium spinosum Figure 16.34

83. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings VII. The Flavobacteria  16.12 Bacteroides and Flavobacterium  16.13 Acidobacteria

84. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.12 Bacteroides and Flavobacterium  Key genera: Bacteroides, Flavobacterium  Bacteroides  Obligately anaerobic  Numerically dominant bacterium in human intestinal tract  Synthesize sphingolipids, which are normally found in mammalian tissues  Flavobacteria  Found primarily in aquatic environments  Aerobic, nutritionally restricted, frequently yellow-pigmented  Other genera are psychrophilic (i.e., Polaribacter)

85. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Sphingolipids Figure 16.35 Glycerol Sphingosine Carboxy group of fatty acid A number of compounds

86. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.13 Acidobacteria  Key genera: Acidobacterium, Geothrix, Holophaga  Gram-negative chemoorganotrophs  Abundant in soils, freshwater habitats, hot spring microbial mats, wastewater treatment reactors, and sewage sludge  16S rRNA gene evidence of up to 6 major groups  Most are still uncultured

87. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings VIII. The Cytophaga Group  16.14 Cytophaga and Relatives

88. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.14 Cytophaga and Relatives  Key genera: Cytophaga, Flexibacter, Rhodothermus and Salinibacter  Long, slender gram-negative rods  Move by gliding  Many Cytophaga digest polysaccharides such as cellulose or chitin  Some are fish pathogens  Cytophaga and Sporocytophaga are obligately aerobic and probably account for much of the oxic cellulose digestion

89. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Cytophaga and Sporocytophaga Figure 16.36a-b Streak of Cytophaga Species Hydrolyzing Agar in Petri Dish Colonies of Sporocytophaga Growing on Cellulose

90. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Cytophaga and Sporocytophaga Figure 16.36c-d Cytophaga hutchinsonii Sporocytophaga myxococcoides

91. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.14 Cytophaga and Relatives  Flexibacter differs from Cytophaga because they require complex media for growth and are not cellulolytic  Common in freshwater saprophytes and soils  None have been identified as pathogenic  Rhodothermus and Salinibacter  Gram-negative, red or yellow pigmented, obligately aerobic  Salinibacter is the most salt tolerant of all Bacteria

92. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings IX. Green Sulfur Bacteria  16.15 Chlorobium and Other Green Sulfur Bacteria

93. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.15 Chlorobium and Other Green Sulfur Bacteria  Key genera: Chlorobium, Chlorobaculum, Prosthecochloris, Chlorochromatium  Green sulfur bacteria are phylogenetically distinct, non-motile, anoxygenic phototrophs  Bacteriochlorophyll a + either bacteriochlorophylls c, d, or e  Utilize H 2 S as an electron donor and oxidize it to SO 4 2-  Autotrophy is supported using a reversal in the citric acid cycle  Have chlorosomes: oblong bacteriochlorophyll-rich bodies bounded by a thin membrane (a lipid monolayer)  Green- and brown-colored species exist

94. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Green and Brown Chlorobia Chlorobaculum tepidum Chlorobaculum phaeobacteroides

95. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Phototrophic Green Sulfur Bacteria Figure 16.37 Chlorobium limicolaChlorobium clathratiforme

96. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Chlorobaculum tepidum Figure 16.38 Chlorobaculum tepidum: a thermophilic green sulfur bacterium Chlorosome

97. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Chlorobaculum tepidum Figure 16.38 chlorosomes

98. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Genera and Characteristics of Green Sulfur Bacteria

99. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.15 Chlorobium and Other Green Sulfur Bacteria  Green sulfur bacteria inhabit anoxic environments rich in H 2 S  Some green sulfur bacteria form consortia  Involves the green sulfur bacterium and a chemoorganotrophic bacterium  Phototrophic member is called epibiont  Epibiont is physically attached to nonphototrophic cell

100. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.15 Chlorobium and Other Green Sulfur Bacteria Chlorochromatium aggregatum Differential contrast DAPI-stained Stained with phylogenetic probe

101. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.16 Spirochetes  Key genera: Spirochaeta, Treponema, Cristispira, Leptospira, Borrelia  Gram-negative, motile, and tightly coiled  Widespread in aquatic environments and in animals  Have endoflagella: located in the periplasm of the cell  Classified into 8 genera based on habitat, pathogenicity, phylogeny, and morphological and physiological characteristics  Also found in the rumen of animals

102. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Morphology of Spirochetes Figure 16.41 Spirochaeta stenostrepta Spirochaeta plicatilis Same magnification

103. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Motility in Spirochetes Figure 16.42

104. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.16 Spirochetes  Spirochaeta  Free-living, anaerobic and facultatively anaerobic spirochetes  Cristispira  Found in nature, primarily in the crystalline style of mollusks  No Cristipara have yet been cultured  Treponema  Anaerobic host-associated spirochetes that are commensal or parasites of humans

105. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.16 Spirochetes  Borrelia  Majority are human or animal pathogens  Borrelia burgdorferi is the causative agent of Lyme disease  B. burgdorferi has a linear chromosome  Leptospira and Leptonema  Strictly anaerobic spirochetes  Rodents are the natural host of Leptospira  Cause of leptospirosis in humans

106. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Cristispira Figure 16.44

107. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Treponema and Borrelia Figure 16.44 Treponema saccharophilum Borrelia burgdorferii Regularly coiled Irregularly coiled

108. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings XI. Deinococci  16.17 Deinococcus and Thermus

109. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.17 Deinococcus and Thermus  Thermus  Thermophilic, aerobic, organotrophic  Source of Taq DNA polymerase  Deinococcus  Gram-positive, aerobic, organotrophic  Most are red or pink due to carotenoids  Resist UV radiation, gamma radiation, and desiccation  Resistant to most mutagenic agents

110. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings The Radiation-Resistant Coccus Deinococcus radiodurans Figure 16.45 Outer membrane layer Nucleoid

111. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings XII. The Green Nonsulfur Bacteria  16.18 Chloroflexus and Relatives

112. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.18 Chloroflexus and Relatives  Key genera: Chloroflexus, Heliothrix, Roseiflexus  Chloroflexus  Thermophilic filamentous bacteria  Form thick microbial mats in neutral to alkaline hot springs  Grows best phototrophically, can grow photoautotrophically  Bacteriochlorophylls a and c  Has chlosomes

113. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.18 Chloroflexus and Relatives  Thermomicrobium  Chemotrophic, strictly aerobic, gram-negative rod  Grow optimally in complex media at 75 o C  Membrane lipids - Have 1,2-dialcohols (instead of glycerol) - Have neither ester nor ether linkage  Lack peptidoglycan

114. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings The Unusual Lipids of Thermomicrobium Figure 16.46 13-methyl-1,2-nonadecaediol of Thermomicrobium roseum Bilayer membrane Fatty acid Phosphate

115. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Green Nonsulfur Bacteria Figure 16.47 Chloroflexus aurantiacus Oscillochloris sp. Chloronema sp. Right: C. Aurantiacus Left: Roseiflexus sp.

116. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings XIII. Hyperthermophilic Bacteria  16.19 Thermotoga and Thermodesulfobacterium  16.20 Aquifex, Thermocrinis, and Relatives  Hyperthermophile: optimal temperature is > 80 o C

117. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.19 Thermotoga and Thermodesulfobacterium  Key genera: Thermotoga, Thermodesulfobacterium  Thermotoga  Rod-shaped, hyperthermophile (can grow at 90°C)  Anaerobic, fermentative, chemoorganotroph  20% of genes likely originated from Archaea (contains many genes that show strong homology to genes from hyperthermophilic Archaea)

118. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Hyperthermophilic Bacteria Figure 16.48 Thermotoga maritima (temperature optimum: 80 o C) Aquifex pyrophilus (temperature optimum: 85 o C)

119. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.19 Thermotoga and Thermodesulfobacterium  Thermodesulfobacterium  Thermophilic (temp. opt. 70 o C), sulfate-reducing bacterium  Strict anaerobe  Unable to utilize acetate as electron donor  Lipids - Ether-linked (instead of ester-linked) - Contain C 17 hydrocarbon along with some fatty acids (instead of phytanyl, the polyisoprenoid C 20 hydrocarbon in Archaea)

120. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Thermodesulfobacterium Figure 16.49

121. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.20 Aquifex, Thermocrinis, and Relatives  Key genera: Aquifex and Thermocrinis  Aquifex  Obligately chemolithotrophic hyperthermophile - H 2, S o, and S 2 O 3 2- as electron donors - O 2 or NO 3- as electron acceptors - Reverse TCA cycle for CO 2 fixation  Most thermophilic of all Bacteria - Opt. temp. 85°C, max. temp. 95°C  1.55 Mbp genome

122. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Hyperthermophilic Bacteria Figure 16.48 Thermotoga maritima (temperature optimum: 80 o C) Aquifex pyrophilus (temperature optimum: 85 o C)

123. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.20 Aquifex, Thermocrinis, and Relatives  Thermocrinis  Chemolithotrophic hyperthermophile - H 2, S o, and S 2 O 3 2- as electron donors - O 2 as electron acceptor - Reverse TCA cycle for CO 2 fixation  Opt. temp. 80°C  Grow as filamentous pink “streamers” in nature - In static culture: grow as individual rod-shaped cells

124. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings Thermocrinis ruber Figure 16.50 85°C outflow, Yellow Stone National Park

125. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings XIV. Nitrospira and Deferribacter  16.21 Nitrospira, Deferribacter, and Relatives

126. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings 16.21 Nitrospira, Deferribacter, and Relatives  Key genera: Nitrospira, Deferribacter  Relatively little is known about these organisms  Chemolithotrophs or chemoorganotrophs  Thermophiles or mesophiles  Identified by ribosomal RNA sequencing

127. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings  Nitrospira group  Nitrospira - Chemolithotroph: NO 2 - as an electron donor - Horizontal transfer of genes involved in nitrification from nitrifying Proteobacteria to Nitrospira? (or vice versa?) - Most of nitrite oxdized in nature is probably due to the activities of Nitrospira ( ∵ Nitrospira is much more common than Nitrobacter in nature ) 16.21 Nitrospira, Deferribacter, and Relatives

128. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings  Nitrospira group  Leptospirillum - Iron-oxidizing chemolithotroph - Responsible for much of the acid mine drainage  Thermodesulfovibrio - Thermophilic sulfate-reducing bacterium - inhabits hot spring microbial mats 16.21 Nitrospira, Deferribacter, and Relatives

129. Copyright © 2009 Pearson Education Inc., publishing as Pearson Benjamin Cummings  Deferribacter group  Deferribacter - Obligately anaerobic - Anaerobic respiration with a variety of electron acceptors (e.g. Fe 3+ and Mn 4+ )  Geovibrio - Obligately anaerobic - Anaerobic respiration with a variety of electron acceptors (e.g. Fe 3+ and Mn 4+ )  Flexistipes - Obligately anaerobic, fermentative 16.21 Nitrospira, Deferribacter, and Relatives