Domain Kingdom Bacteria Domain Kingdom Archaea and Viruses

Domain (Kingdom) Bacteria, Domain (Kingdom) Archaea, and Viruses Chapter 17

Outline v v v v v Introduction Features of Kingdoms (Domains) Bacteria and Archaea Domain Bacteria (Kingdom Bacteria) – The True Bacteria Human Relevance of the Unpigmented Purple, and Green Sulfur Bacteria Class Cyanobacteriae – The Cyanobacteria (Blue-Green Bacteria) Class Prochlorobacteriae – The Prochlorobacteria Kingdom Archaea (Domain Archaea) – The Archaebacteria Viruses Viroids and Prions

Introduction v v v Fossils of bacteria - 3. 5 billion years old Fossils of 1 st eukaryotic cells - 1. 3 billion years old 5, 000 species of bacteria recognized today • Each species found in astronomical numbers − Difficult to classify simple one-celled organisms = # of bacteria species uncertain − Strains of one species look alike Ø Clustered by what they do

Features of Kingdoms (Domains) Bacteria and Archaea v All have prokaryotic cells • No nuclear envelopes • Have long circular strand of DNA, ribosomes, membranes and plasmids • No membrane-bound organelles, such as plastids, mitochondria, dictyosomes, endoplasmic reticulum Section of Prochloron cell

Features of Kingdoms (Domains) Bacteria and Archaea v v v Nutrition • Primarily by absorption of food in solution through cell wall • Some by chemical reactions or by photosynthesis Reproduction predominately asexual, by fission • Fission - no mitosis, DNA strand duplicates and distributed to new cells No sexual reproduction – Genetic recombination facilitated by pili or by close contact of cells

v Features of Kingdoms (Domains) Bacteria and Archaea Cellular Detail and Reproduction of Bacteria Folds of plasma and other membranes perform some of functions of organelles in eukaryotic cells v Ribosomes present, but about ½ size of eukaryotic cells v Nucleoid - single chromosome in form of ring v 30 or 40 plasmids may be present • Plasmids - small circular DNA molecules that replicate independently of chromosome • Entire complement of plasmids consists of multiple copies of one or few different DNA molecules

v v Features of Kingdoms (Domains) Bacteria and Archaea Cellular Detail and Reproduction of Bacteria Mitosis does not occur Fission • 2 copies of duplicated chromosomes migrate to opposite ends of cell • Perpendicular walls and cell membranes formed in middle of cell • 2 new cells separate and enlarge to original size Replication of nucleoid

v Features of Kingdoms (Domains) Bacteria and Archaea Cellular Detail and Reproduction of Bacteria Fission cont’d. • May undergo fission every 10 - 20 minutes under ideal conditions − Usually exhaust food supplies and accumulate wastes New wall growing inward of dividing bacterial cell

v v Features of Kingdoms (Domains) Bacteria and Archaea Cellular Detail and Reproduction of Bacteria No gametes or zygotes, and no meiosis 3 Forms of Genetic Recombination: • Conjugation - DNA transferred from donor cell to recipient cell usually through pilus (plural: pili) • Transformation - living cell acquires DNA fragments released by dead cells • Transduction - DNA fragments carried from one cell to another by viruses Conjugation

v Features of Kingdoms (Domains) Bacteria and Archaea Size, Form, and Classification of Bacteria Most bacteria >2 or 3 μm in diameter v Occur in 3 forms: Cocci Spherical or elliptical Bacilli Rod-shaped or cylindrical Spirilla Helix or spiral

Features of Kingdoms (Domains) Bacteria and Archaea Size, Form, and Classification of Bacteria v Also classified by: • Presence of sheath around cells, hair-like or bud-like appendages, endospores, pili or flagella • Color • Mechanisms of movement • Biochemical characteristics • Reaction of cell walls to dye − Gram-negative − Gram-positive

Domain Bacteria (Kingdom Bacteria) – The True Bacteria v v True bacteria have muramic acid in cell walls, and different from archaebacteria in RNA bases, metabolism and lipids Phylum Bacteriophyta • Class Bacteriae - unpigmented, purple, and green sulfur bacteria − Most heterotrophic - cannot synthesize own food Ø Majority saprobes - food from nonliving organic matter Ø Some parasites - depend on living organisms for food

Domain Bacteria (Kingdom Bacteria) – The True Bacteria v Phylum Bacteriophyta • Autotrophic Bacteria - synthesize organic compounds from simple inorganic substances − Photosynthetic without producing O 2 Ø Purple Sulfur Bacteria - bacteriochlorophyll pigments, use H 2 S Ø Purple Nonsulfur Bacteria - bacteriochlorophyll pigments, use H 2 Ø Green Sulfur Bacteria - chlorobium chlorophyll pigments, use H 2 S − Photosynthetic and produce O 2 Ø Cyanobacteria and Chloroxybacteria

Domain Bacteria (Kingdom Bacteria) – The True Bacteria v Phylum Bacteriophyta • Autotrophic bacteria cont’d. − Chemotrophic Bacteria - obtain energy from various compounds or elements through oxidation Ø Iron Bacteria - transform soluble Fe to insoluble Ø Ø Sulfur Bacteria - convert H 2 S gas to S or S to SO 42 Hydrogen Bacteria – use H 2 derived from anaerobic or N 2 -fixing bacteria

Human Relevance of the Unpigmented, Purple, and Green Sulfur Bacteria v v Composting and compost • Bacteria decompose organic waste to form compost True bacteria and disease • Bacteria involved in diseases of plants, animals and humans, and in losses of food • Modes of access of disease bacteria – Air Ø Coughs, sneezes - saliva droplets contain bacteria Ø Diphtheria, whooping cough, some meningitis forms, pneumonia, strep throat, tuberculosis

Human Relevance of the Unpigmented, Purple, and Green Sulfur Bacteria v True bacteria and disease cont’d. • Modes of access of disease bacteria cont’d. − Contamination of food and drink Ø Food poisoning and diseases associated with natural disasters » Cholera, dysentery, Staphylococcus and Salmonella food poisoning Ø Legionnaire disease Ø Botulism Ø Escherichia coli

Human Relevance of the Unpigmented, Purple, and Green Sulfur Bacteria v True bacteria and disease cont’d. • Modes of access of disease bacteria cont’d. − Direct contact - enter through skin or mucus membranes Ø Syphilis, Gonorrhea, anthrax, brucellosis − Wounds Ø Tetanus and gas gangrene − Bites of insects and other organisms Ø Bubonic plague, tularemia, rickettsias, mycoplasmas, Lyme disease

Human Relevance of the Unpigmented, Purple, and Green Sulfur Bacteria v Koch’s Postulates - rules for proving particular microorganism cause of particular disease • Microorganism must be present in all cases of disease • Microorganism must be isolated from victim in pure culture • Microorganisms from pure culture must be able to infect hosts • Microorganism must be isolated from experimentallyinfected host and grown in pure culture for comparison with original culture

Human Relevance of the Unpigmented, Purple, and Green Sulfur Bacteria v True bacteria useful to humans • Biological Control organisms − Bacillus thuringiensis effective against caterpillars and worms Ø Multiplies in digestive tract and paralyzes gut − Bacillus popilliae - effective against Japanese beetle grubs • Bioremediation - use of living organisms in cleanup of toxic waste and pollution Affect of Bacillus thuringiensis on tomato hornworm

Human Relevance of the Unpigmented, Purple, and Green Sulfur Bacteria v True bacteria useful to humans cont’d. • Other useful bacteria − Human health - Lactobacillus acidophilus Ø Aids in digestion Ø Used for elimination of yeast infections − Dairy - buttermilk, sour cream, yogurt, cheese − Industrial - utilizes bacteria waste products Ø Solvents, explosives, ascorbic acid (vitamin C), citric acid

Class Cyanobacteriae – The Cyanobacteria (Blue-Green Bacteria) v Distinctions between cyanobacteria and traditional bacteria • Has chlorophyll a and O 2 produced from photosynthesis • Contain phycobilins • Can fix N 2 and produce O 2

Class Cyanobacteriae – The Cyanobacteria (Blue-Green Bacteria) v Distribution in diverse variety of habitats • Pools and ditches, particularly if polluted • Fresh and marine water, but not acidic water (plankton) • Waters of various temperatures hot springs at Yellowstone National Park • Often 1 st photosynthetic organisms after volcanic eruption • Symbiotic with other organisms Yellowstone – Amoebae, sea anemones, lichens, cycads

Class Cyanobacteriae – The Cyanobacteria (Blue-Green Bacteria) v Form, metabolism, and reproduction • Often chains, or colonies held together by gelatinous sheaths • Cells blue-green in color in ca. 50% of approximately 1, 500 spp. • Produce nitrogenous food reserve - cyanophycin • Flagella unknown

Class Cyanobacteriae – The Cyanobacteria (Blue-Green Bacteria) v Form, metabolism, and reproduction cont’d. • New cells by fission or fragmentation of colonies or filaments • Heterocyst - large colorless, N 2 -fixing cell • Akinetes - thick-walled cells that resist adverse conditions

Class Cyanobacteriae – The Cyanobacteria (Blue-Green Bacteria) v Cyanobacteria, chloroplasts, and O 2 • Chloroplasts originated as cyanobacteria or prochlorobacteria living within other cells • Fossils of cyanobacteria, 3. 5 bya, found in Australia • 3 bya, cyanobacteria produced O 2 as by-product of photosynthesis • O 2 accumulated in atmosphere, becoming substantial 1 bya • Accumulation of O 2 resulted in appearance of other photosynthetic organisms and forms of aerobic respiration • In last half billion years enough ozone for UV shield and for photosynthetic organisms to survive on land

Class Cyanobacteriae – The Cyanobacteria (Blue-Green Bacteria) v Human relevance of the cyanobacteria • Among many aquatic and photosynthetic organisms at bottom of various food chains • Often abundant in bodies of fresh water in warmer months − Algal Blooms - can be poisonous to livestock • Food - Spirulina with significant vitamin content • Swimmers itch • N 2 fixation

Class Prochlorobacteriae – The Prochlorobacteria v v Have chlorophylls a and b, but no phycobilins • Adds to theory that chloroplasts originated from cells living within cells of other organisms Cell structure and chemistry similar to cyanobacteria and other true bacteria Prochloron

Kingdom Archaea (Domain Archaea) – The Archaebacteria v v v Metabolism fundamentally different from other lines of bacteria Differ from true bacteria by unique sequences of bases in RNA, by lack of muramic acid in walls, and by production of distinct lipids Methane Bacteria • Killed by O 2 • Active only under anaerobic conditions − Energy from generation of CH 4 from CO 2 and H 2

Kingdom Archaea (Domain Archaea) – The Archaebacteria v Salt Bacteria • Metabolism enables to thrive under extreme salinity − Carry out simple photosynthesis with aid of bacterial rhodopsin Lake Bonneville, Utah with very high salt content

Kingdom Archaea (Domain Archaea) – The Archaebacteria v Sulfolobus Bacteria • Occur in sulfur hot springs • Metabolism allows to thrive at very high temperatures − Mostly in vicinity of 80 o. C (170 o. F), some even higher • Shape of ribosomes and chemistry of sulfolobus bacteria distinguishes them from other archaebacteria, true bacteria and eukaryotes

Kingdom Archaea (Domain Archaea) – The Archaebacteria v Human relevance of the archaebacteria • CH 4 bacteria produce CH 4 as they digest organic wastes in absence of O 2 − May be used to furnish energy for engines, heating and cooking − Has high octane level and clean and nonpolluting − Produced on large-scale when organic wastes fed into CH 4 digester Ø Leftover sludge makes excellent fertilizer

Viruses • Size and structure: • Represent interface between biochemistry and life − Lack cytoplasm or cellular structure − Don’t grow by increasing in − − size or dividing Don’t respond to external stimuli Can’t move on their own Can’t carry on independent metabolism Express their genes and produce more virus particles using host cell Papavoviruses in a human wart • About size of large molecules, 15 -300 nm

Viruses v Size and structure cont’d. • Consist of nucleic acid core surrounded by protein coat • Architecture of protein coat varies − 20 -sided, or head and tail • Core consists of DNA or RNA, not both • Classified according to DNA or RNA, then according to size and shape, nature of protein coats, and # of identical structural units in cores Bacteriophage • Bacteriophages - viruses that attack bacteria

Viruses v Viral reproduction • Viruses replicate at expense of host cells − Attach to susceptible cell − Penetrate to cell interior − DNA or RNA dictates synthesis of new molecules − New viruses released from host cell Ø Host cell dies • Some can mutate very rapidly – As result, new vaccines need to be developed Bacteriophage replication

Viruses v Human relevance of viruses • Annual loss in work time due to common cold and influenza viruses amount to millions of hours − Immunizations dramatically decreased incidence of many viral diseases (i. e. , chicken pox, German measles, and mumps) • AIDS − Retrovirus - virus with 2 identical nuclear strands Ø Evolves extremely quickly » ~1 million times faster than cellular organisms • Used to infect disease organisms of animals and plants − Ticks, insects, possibly gypsy moths

Viroids and Prions v v Viroids - circular strands of RNA that occur in nuclei of infected plant cells • Transmitted from plant to plant via pollen, ovules, or machinery − Cause more than dozen plant diseases Prions - appear to be particles of protein that cause diseases of animals and humans • Believed to cause disease by inducing abnormal folding of proteins in brain, resulting in brain damage − Cruetzfeldt-Jacob disease

Review v v v v v Introduction Features of Kingdoms (Domains) Bacteria and Archaea Domain Bacteria (Kingdom Bacteria) – The True Bacteria Human Relevance of the Unpigmented Purple, and Green Sulfur Bacteria Class Cyanobacteriae – The Cyanobacteria (Blue-Green Bacteria) Class Prochlorobacteriae – The Prochlorobacteria Kingdom Archaea (Domain Archaea) – The Archaebacteria Viruses Viroids and Prions