Bacteria and Archaea Image Getty Images Learning Objectives Distinguish a bacterial cell from a eukaryotic Distinguish the two major kinds of Bacterial Distinguish Archaea from Bacteria Eukarya Describe the evidence that links Archaea to Discuss the importance of Bacteria and EUKARYA cell cells Eukarya Archaea ARCHAEA BACTERIA Bacteria and Archaea lack a nucleus Vibrio Bacteria Proteobacteria Prokaryotes before nucleus Prokaryotes is not a monophyletic group Methanococcus Archaea Euryachaeota nucleus and other organelles cells metabolism DNA etc EUKARYA ARCHAEA BACTERIA Chlamydomonas Eukarya Archaeplastida Oldest Fossils of Life on Earth are of Bacteria 3 5 3 8 billion years ago Therefore bacteria were around for about 2 billion years all by themselves before eukaryotes made an appearance Stromatolites Phylogenetic diversity ARCHAEA CRENARCHAEOTA THAUMARCHAEOTA EURYARCHAEOTA PROTEOBACTERIA FIRMICUT ES ACTINOBACTERIA R I A E T C A B O N A Y C BACTERIA PVC GROUP OPISTHOKONTS animals fungi and allies EUKARYA AMOEBOZOA amoebas and slime molds EXCAVATA euglenids parasites symbiotes SAR brown algae alveolates forams cercozoans radiolarians ARCHAEPLASTIDA PLANTS green plants red plants and allies In more than 3 billion years life has diverged greatly in all the 3 domains BASAL EXTREMOPHIL ES P U O R G B C F I S P R O C H A E T E S C H L O R O F D E I T N H O L E X I E C R O M C U C S U S Check out the Tree of Life web site www tolweb org if you are interested in learning more about such things Bacterial diversity as revealed by metagenomic studies Microbes make up most of the phylogenetic diversity on Earth Most microbial groups are only known from DNA sequences specifically of the 16S ribosomal gene Hug et al 2016 Morphology of bacteria Variable shapes Presence of structures such as flagella and fimbriae Spirochete Stalked Cocci Rods Filaments Morphology of bacteria Relative Size Comparison in sizes of viruses bacteria and eukaryotic cells Comparative sizes of various prokaryotes Stop Check this out Candidatus Ca Thiomargarita magnifica Gram staining behavior correlates to the type of cell wall and presence absence of an outer membrane BASAL EXTREMOPHIL ES DEINOCOCCUS THERMUS CHLOROFLEXI SPIROCHAETES FCB GROUP PVC GROUP CYANOBACTER IA ACTINOBACTERI A FIRMICUTES I A R E T C A B Phylogenetic distribution of gram negative and gram positive bacteria gram negative Gram positive bacteria may be monophyletic gram negative are not PROTEOBACTERIA gram negative gram positive Most Bacteria make their cell walls out of a substance called peptidoglycan which is made from both protein and carbohydrate gram negative Outer membrane gram positive The peptidoglycan wall is a common target for organisms that kill or otherwise inhibit the growth of Bacteria Cell Wall Plasma membrane cytosol Penicillin Penicillin Alexander Fleming Penicllium fungi Physiological tests to identity species of bacteria Physiological tests API strips identify species within Enterobacteriaeae some gram positive bacteria and yeasts Analytical Profile Index 20 miniature biochemical tests carbon catabolism enzyme activity etc Most Bacteria are heterotrophic using respiration or fermentation BASAL EXTREMOPHILE S DEINOCOCCUS THERMUS CHLOROFLEXI Almost all Bacteria are capable of glycolysis Most can perform some kinds of respiration aerobic or anaerobic suggesting that carbon catabolism was invented once in the common ancestor However the ability of a given bacterium to use a particular carbon source e g citrate glycerol etc varies depending on the genes present SPIROCHAETES FCB GROUP PVC GROUP CYANOBACTERIA ACTINOBACTERIA I H T W S P U O R G S H P O R T O R E T E H FIRMICUTES PROTEOBACTERIA BASAL EXTREMOPHILE S DEINOCOCCUS THERMUS CHLOROFLEXI SPIROCHAETES FCB GROUP PVC GROUP CYANOBACTERI A ACTINOBACTERIA P H O T O T R O P H S G R O U P S W T H I FIRMICUTE S PROTEOBACTERIA However photosynthesis is present in many groups as well Bacteria affect us in many ways both positive and negative Many bacteria are the cause of human diseases Others are opportunistic and can cause diseases when given the chance Stomach ulcers Tuberculosis Leprosy Mycobacterium leprae Sexually transmitted diseases a Gonorrhea b Syphilis c Chlamydia d Lyme disease Bubonic plague Many many many more Bacteria affect us in many ways both positive and negative Some bacteria also cause problems for our crops Fire Blights Spots Cankers or Weeps Cankers and Leaf Spots Witch s Brooms Yellows and Stunts Cyanobacteria Anabaena with heterocysts Bacteria affect us in many ways both positive and negative But some bacteria turn out to be useful Food production yogurts cheeses vinegars etc Bacillus thuringiensis Bt is used as an insecticide Many bacteria are used in bioremediation A lot of our antibiotics are made by other bacteria Without bacteria we d quickly run out of organic nitrogen Used in biotechnology e g in molecular cloning Penicillin type antibiotics are often much more effective against gram positive bacteria compared to gram negative bacteria Why A gram negative bacteria mutate at a higher rate and become resistant quicker B The outer membrane of gram negative bacteria slows the ability of the antibiotic to reach the peptidoglycan and affect the cells C gram positive cells need to have a thicker cell wall and thus need more peptidoglycan to survive D the positive charge on the gram positive cells attracts the penicillin from the solution much more strongly than the negative charge on the gram negative cells If you took a flask full of bacteria and a flask full of chickenpox virus and added glucose i e food to both and let them sit for a day what would you expect to happen in the flask of bacteria A Nothing will happen B The number of bacteria in the flask will increase C The number of bacteria in the flask will go down what would you expect to happen in the flask of viruses A Nothing will happen B The number of viruses in the flask will increase C The number of viruses in the flask will go down The sister clade of bacteria is the group Archaea Eukarya 4000 3000 2000 1000 0 1 Cell membrane composition mya Synapomorphies 2 Information nucleic acid processing and storage 3 Metabolic enzymes 4 DNA Homology of multiple genes BACTERIA ARCHAEA EUKARYA Many traits What are the Archaea like Discovered in the 1970s based on DNA evidence They look and act a lot like Bacteria smaller than Eukaryotes no nucleus circular chromosome Some have stranger shapes squares sheets