Chapter 14 Lecture Outline Domain Kingdom Bacteria Domain

Outline v Introduction v Features of Kingdoms (Domains) Bacteria and Archaea v Domain Bacteria (Kingdom Bacteria) – The True Bacteria v v 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 v Viruses v Viroids and Prions

Introduction v v v Fossils of bacteria - 3. 5 billion years old Fossils of first eukaryotic cells - 1. 3 billion years old Bacteria found in astronomical numbers today. • Approximately 10 million to 1 billion – Much debate as to method of classification

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 Nutrition: • Primarily by absorption of food in solution through cell wall • Some by chemical reactions or by photosynthesis v Reproduction predominately asexual, by fission. • Fission - No mitosis, DNA strand duplicates and is distributed to new cells. v No sexual reproduction • Genetic recombination facilitated by pili or by close contact of cells.

Features of Kingdoms (Domains) Bacteria and Archaea Cellular Detail and Reproduction of Bacteria v v Folds of plasma and other membranes perform some of functions of organelles in eukaryotic cells. Ribosomes present, but about half the size as those 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.

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

Features of Kingdoms (Domains) Bacteria and Archaea Cellular Detail and Reproduction of Bacteria v Fission: • 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

Features of Kingdoms (Domains) Bacteria and Archaea Cellular Detail and Reproduction of Bacteria v v Do not produce gametes or zygotes, and do not undergo meiosis Three Forms of Genetic Recombination: • Conjugation – DNA transferred from donor cell to recipient cell usually through pilus (pleural: pili). • Transformation – Living cell acquires DNA fragments released by dead cells. • Transduction – DNA fragments carried from one cell to another by viruses. Conjugation

Features of Kingdoms (Domains) Bacteria and Archaea v Size, Form, and Classification of Bacteria Most bacteria less than 2 or 3 micrometers in diameter. v Occur primarily in three 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, of hair-like or bud-like appendages, of endospores, of pili or of 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 are different from archaebacteria in their RNA bases, metabolism and lipids. Phylum Bacteriophyta • Class Bacteriae - Unpigmented, purple, and green sulfur bacteria – Most heterotrophic - Cannot synthesize own food o Majority saprobes - Food from nonliving organic matter « Responsible for decay and recycling of organic matter in soil o 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 oxygen o Purple sulfur bacteria - Bacteriochlorophyll pigments, use hydrogen sulfide o Purple nonsulfur bacteria - Bacteriochlorophyll pigments, use hydrogen o Green sulfur bacteria - Chlorobium chlorophyll pigments, use hydrogen sulfide Photosynthetic and produce oxygen - Cyanobacteria and chloroxybacteria

Domain Bacteria (Kingdom Bacteria) – The True Bacteria v Phylum Bacteriophyta • Autotrophic bacteria – Chemotrophic bacteria - Obtain energy from various compounds or elements through oxidation o Iron bacteria - Transform soluble iron to insoluble o Sulfur bacteria - Convert hydrogen sulfide gas to sulfur or sulfur to sulfate o Hydrogen bacteria - Use molecular hydrogen derived from anaerobic or nitrogen-fixing bacteria

Human Relevance of the Unpigmented, Purple, and Green Sulfur Bacteria v Composting and compost: • Bacteria decompose organic waste to form compost. v True bacteria and disease: • Bacteria involved in diseases of plants, animals and humans, and in losses of food • Modes of access of disease bacteria: – Access from the air o o Coughs, sneezes - Saliva droplets contain bacteria. 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: • Modes of access of disease bacteria: – Access through contamination of food and drink o Food poisoning and diseases associated with natural disasters « Cholera, dysentery, Staphylococcus and Salmonella food poisoning o Legionnaire disease o Botulism o Escherichia coli

Human Relevance of the Unpigmented, Purple, and Green Sulfur Bacteria v True bacteria and disease: • Modes of access of disease bacteria: – Access through direct contact - Enter through skin or mucus membranes o Syphilis, Gonorrhea, Chlamydia, anthrax, brucellosis – Access through wounds o Tetanus and gas gangrene – Access through bites of insects and other organisms o Bubonic plague, tularemia, rickettsias, mycoplasmas, Lyme disease

Human Relevance of the Unpigmented, Purple, and Green Sulfur Bacteria v Koch’s postulates - Rules for proving a particular microorganism is cause of a 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 experimentally -infected 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 o – 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: • Other useful bacteria – Human health - Lactobacillus acidophilus o Aids in digestion o Used for elimination of yeast infections – Dairy - Buttermilk, sour cream, yogurt, cheese – Industrial - Utilizes bacteria waste products o Solvents, explosives, ascorbic acid (vitamin C), citric acid

Class Cyanobacteriae – The Cyanobacteria (Blue-Green Bacteria) v Distinctions between traditional bacteria and cyanobacteria: • Cyanobacteria have chlorophyll a and oxygen is produced from photosynthesis. • Cyanobacteria contain phycobilins. • Cyanobacteria can both fix nitrogen and produce oxygen.

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 – Principal photosynthetic organisms in plankton • Waters of various temperatures - Hot springs at Yellowstone National Park • Often first photosynthetic organisms after volcanic eruption Yellowstone • Symbiotic with other organisms – Amoebae, sea anemones, fungi (producing lichens), cycads

Class Cyanobacteriae – The Cyanobacteria (Blue-Green Bacteria) v Form, metabolism, and reproduction: • Often in chains, or colonies held together by gelatinous sheaths • Cells blue-green in color in about half of the approximately 1, 500 species. • Produce nitrogenous food reserve - Cyanophycin • Flagella unknown

Class Cyanobacteriae – The Cyanobacteria (Blue-Green Bacteria) v Form, metabolism, and reproduction: • New cells by fission, or by fragmentation of colonies or filaments. • In Nostoc and Anabaena, fragmentation often occurs at heterocyst. – – Heterocyst - Large colorless, nitrogen-fixing cell Also produce akinetes o Akinetes - Thick-walled cells that resist adverse conditions

Class Cyanobacteriae – The Cyanobacteria (Blue-Green Bacteria) v Cyanobacteria, chloroplasts, and oxygen • Thought that chloroplasts originated as cyanobacteria or prochlorobacteria living within other cells. • Fossils of cyanobacteria, 3. 5 billion years old, found in Australia. • 3 billion years ago, cyanobacteria produced oxygen as by- product of photosynthesis. • Oxygen accumulated in atmosphere, becoming substantial 1 billion years ago. • As oxygen accumulated, other photosynthetic organisms appeared and forms of aerobic respiration developed. • 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: • Cyanobacteria are among the many aquatic and photosynthetic organisms at the bottom of various food chains. • Often become abundant in bodies of fresh water in warmer months – Algal blooms o Can be poisonous to livestock • Food - Spirulina with significant vitamin content • Swimmers itch • Nitrogen fixation

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

Kingdom Archaea (Domain Archaea) – The Archaebacteria v v v Metabolism is 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 oxygen • Active only under anaerobic conditions – Energy derived from generation of methane gas from carbon dioxide and hydrogen.

Kingdom Archaea (Domain Archaea) – The Archaebacteria v Salt bacteria • Metabolism enables these bacteria 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 these species 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: • Methane bacteria produce methane gas as they digest organic wastes in absence of oxygen. – Methane may be used to furnish energy for engines, heating and cooking. – Methane has a high octane level and is clean and nonpolluting. – Methane produced on large-scale when organic wastes fed into methane digester. o Leftover sludge makes excellent fertilizer.

Viruses v Size and structure: • Represent interface between biochemistry and life – Lack cytoplasm or cellular structure o o o – Do not grow by increasing in size or dividing Do not respond to external stimuli Cannot move on their own Cannot carry on independent metabolism Inside living cells, they express their genes and use cellular machinery to produce more virus particles. Papavoviruses in a human wart About size of large molecules, 15 -300 nanometers

Viruses v Size and structure: • 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 number of identical structural units in their cores. • Bacteriophages - Viruses that attack bacteria

Viruses v Viral reproduction: • Viruses replicate at expense of their host cells. – Attach to susceptible cell – Penetrate to cell interior – DNA or RNA dictates synthesis of new molecules. – New viruses released from host cell. o – Host cell dies. Some can mutate very rapidly. o As a 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 alone amount to millions of hours. – Immunizations have dramatically decreased incidence of many viral diseases such as chicken pox, German measles, and mumps. • AIDS – Retrovirus - A virus with two identical nuclear strands o Evolves extremely quickly « About a million times faster than cellular organisms • Used to infect disease organisms of animals and plants – Ticks, insects, possibly gypsy moths

Viroids and Prions v Viroids - Circular strands of RNA that occur in nuclei of infected plant cells • Transmitted from plant to plant via pollen, ovules, or machinery – v Cause more than a 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 Introduction v Features of Kingdoms (Domains) Bacteria and Archaea v Domain Bacteria (Kingdom Bacteria) – The True Bacteria v v 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 v Viruses v Viroids and Prions