Kingdom Monera What are PROKARYOTES? TEM of dividing cell No nucleus No chloroplasts No mitochondria They are ancient life forms known as bacteria Two major clades of bacteria Archaebacteria & Eubacteria Methanogens Extreme Thermophiles Extreme Halophiles Cyanobacteria Cyanobacteria (Blue-green algae) & other Gram negative bacteria Gram positive bacteria

Prokaryotes Lack Organelles (w/ 2 membranes) No nucleus No chloroplasts No mitochondria Other constituents? Cell walls; Storage molecules for N, P, C Gas vacuoles; Small ribosomes (70S) for protein synthesis but have DNA & RNA but have pigments, thylakoids & enzymes for PS but have respiratory chain & membranes

Geoclock Origin of life

Cyanophytes established early aerobic environments. Evolution of advanced aerobes “Primordial ANAEROBIC soup” 2 H 2 O + CO 2 2 H 2 O + CO 2  2 O 2 + CH 2 O + H 2 O

MYAERAPERIOD DOMINANT LIFE FORM 2Quaternary Age of angiosperms 65CenozoicTertiary 150Cretaceous Rise of angiosperms 200Jurassic Age of cycads 250MesozoicTriassic Rise of cycadophytes 300Permian Rise of conifers 350Carboniferous Age of lycopods, ferns, sphenopsids; Rise of mosses 400Devonian Age of vascular plants; 1st seed plants 450Silurian 1st vascular plants 500Ordovician Age of eukaryotic algae 600Cambrian Rise of eukaryotic algae and fungi 4500Precambrian Rise of prokaryotes More conventional geologic time table

Bacteria that are: Photosynthetic (convert light energy to food) Produce O 2 as a byproduct of photosynthesis Some have capacity to fix N 2 into NH 4 Some produce toxins Some have formed millions of years old stromatolites as living structures Division Cyanophyta TEM of dividing cell Cyanophytes have changed the path of evolution on earth

General features - defining characteristics Developmental lineages – using morphology to understand evolution Ecology – understanding roles in interacting with other species Evolution – diversity and change over time Commercial interests – exploit ecology Things we will cover

General features 150 genera 2000 species, Habitats: virtually everywhere OceansFreshwater SoilHotsprings Epiphytes Gram negative bacteria Morphological Range: Endophytes Cell Walls: Ancient organisms but well suited to earth’s habitats Unicells to complex multicell organisms Trichodesmium blooms can cover 2x10 6 km 2 and be seen via satellites NASA

Diversity

Being comprised of only 20% peptidoglycan, the cell wall of Gram-negative bacteria is much thinner than Gram-positive bacteria. Gram-negative bacteria have two unique regions which surround the outer plasma membrane: i) periplasmic space and ii) lipopolysaccharide layer. periplasmic space separates the outer plasma membrane from the peptido- glycan layer. lipopolysaccharide layer is adjacent to the exterior peptidoglycan layer Cell Walls

Pigments - photosynthesis General features Chlorophyll a Chlorophyll a Phycobilins Phycobilins Phycoerythrin Phycocyanin Allophycocyanin Others Carotenoids Carotenoids UV absorbing molecules UV absorbing molecules Storage Products Growth

Photosynthesis & Pigments Chl a Phycobilins sunlight Light energy is harvested by the cell Cell thylakoids Only specific colors are absorbed Other colors are reflected back to your eye Other colors are reflected back to your eye

C hlorophyll a Phytol Chain Tetrapyrrole Ring

Phycobilins Open tetrapyrrole phycocyanin phycoerythrin

Photosynthesis & Pigments Chlorophyll a Arrangement of light Arrangement of light harvesting structure is specific and detailed

Pigments - photosynthesis General features Chlorophyll a Chlorophyll a Phycobilins Phycobilins Phycoerythrin Phycocyanin Allophycocyanin Others Carotenoids Carotenoids UV absorbing molecules UV absorbing molecules Storage Products Starch (C) Starch (C) Cyanophycin (N) Cyanophycin (N) Poly P i bodies Poly P i bodies Growth

Storage products ATP Starch C = black O = red H = white C = green = blue = blue H = red = white = white P = purple

Cell walls ? Storage molecules for N, P, C ? Floatation? Small ribosomes (70S) DNA & RNA Pigments, thylakoids & enzymes for PS Respiratory chain & membranes General features What is in a typical cyanophyte cell?

Pigments - photosynthesis General features Chlorophyll a Chlorophyll a Phycobilins Phycobilins Phycoerythrin Phycocyanin Allophycocyanin Others Carotenoids Carotenoids UV absorbing molecules UV absorbing molecules Storage Products Starch (C) Starch (C) Cyanophycin (N) Cyanophycin (N) Poly P i bodies Poly P i bodies Growth Every cell can  Every cell can  True branching True branching False branching False branching Multicellular organisms: Multicellular organisms: Fragments regrow “Spores” “Spores” regrow Akinetes germinate Branching Branching

Growth & morphology Binary Fission (cell division) Produces genetically identical “offspring” or twins Increases the numbers of cells in the population by exponential growth, 2 n Cell division for unicells Cell division for unicells:    8  16 cells Divisions may be every 15 to 20 min

Growth & morphology Unicell populations grow rapidly Starting with 1 cell: 10 rounds of division  1,000 + cells It’s not unusual to have 10 6 to 10 8 cells / mL in “blooms” It’s not unusual to have 10 6 to 10 8 cells / mL in “blooms” Cyanotech ponds

Developmental lineages Evaluate adult form to gain insight in possible evolutionary processes. Step-by-step acquisition of new traits via genetic change. Examine reproductive cells and other characters as additional data. Useful means to construct evolutionary hypotheses to test with molecular data.

Growth & morphology Order Chroococcales Evolution has taken a simple shape Developmental Lineage #1 to more complex but related forms to more complex but related forms: Multicellular genera Multicellular genera All cells appear virtually identical - internally Genetic change

Order Chroococcales Merismopedia Diversity Microcystis

Growth & morphology Coordinated binary fission of all cells in colony 1 colony 2 colonies Multicellular organisms divide but increase the number of entities in the population 

Growth & morphology Order Chamaesiphonales Developmental Lineage #2 Evolution has taken a simple shape: attachment to the substrate attachment to the substrate spores released from upper end of cell spores released from upper end of cell

Growth & morphology Evolution has taken a simple shape: constrained cells into chains constrained cells into chains formed arrays of trichome(s) in sheaths formed arrays of trichome(s) in sheaths trichome (no sheath evident) trichome + sheath (filament) Developmental Lineage #3 Order Nostocales trichomes + sheath false branching can result

Diversity Order Nostocales

Growth & morphology Order Nostocales False branching 1. Rupture of sheath and cells : 2. Remaining cells at both ends continue to grow 3. Both trichomes push through weakened sheath What to look for? Is there a change in the plane of cell division?

New Cell Types Nitrogen fixation supports protein synthesis 1. Low N in environment 2. Cell differentiates as a specialized cell, the heterocyst 3. Creates setting for Nitrogenase enzyme 4. Enzyme converts N 2  NH 4 + polar heterocysts Order Nostocales

Growth & morphology Order Nostocales Nitrogen fixation & Azolla in rice fields replace fertilizers 1. Low N in environment 2. Heterocysts differentiate 3. Enzyme converts N 2  NH Water fern benefits from fertilizer intercalary heterocysts 5. Rice fields are more productive

Other cell types Order Nostocales Akinete Anabaena

Cool stuff

Growth & morphology Developmental Lineage #4 Order Stigonematales Evolution has taken a simple shape: formed arrays of cells that divide in 2 directions (planes) formed arrays of cells that divide in 2 directions (planes) True branching Multiseriate tissues

Growth & morphology Order Stigonematales True branching 1. No rupture of sheath or cells : 2. Cells divide in two planes 3. Create new structures, branches What to look for? Is there a change in the plane of cell division?

Growth & morphology Complex tissue Order Stigonematales Multicellular Multicellular Organized multiseriate layers Organized multiseriate layers Cell dimorphism Cell dimorphism

Vocabulary prokaryote thylakoidchloroplast mitochondrion eukaryote heterocystakinete multiseriate phycobilins phycobilisome binary fission nucleus trichomesheath false branching nitrogenase Azolla Anabaena uniseriate accessory pigment true branching photosynthesis Lyngbya Stigonema

Who am I?

National Geographic: An underworld of hydrogen sulfide harbors life-forms awesome and awful: Margulis, L. (1970). Origin of eukaryotic cells. Yale University Press, New Haven. Scientific American Extremophiles: Mereschowsky, C., (1910). Theorie der zwei Plasmaarten als Grundlage der Symbiogenesis, einer neuen Lehre von der Entstehung der Organismen., Biol. Centr. 30, , Mereschowsky, C., (1905). Über Natur und Ursprung der Chromatophoren im Pflanzenreiche., Biol. Centr. 25, & NASA interactive page Powers of ten interactive page: Reading & Viewing Viewing

Saratoga Springs NY / Picture credits