Chapter 101.docx

Chapter 10 How to classify bacteria There are about 1.7 billion organisms To study they must be separated (organisms) into groups. Diversity – because of natural selection (survival) of stronger traits more suited for environmental Similarity – is due to relatedness, this comes from evolution Taxono...

Chapter 10 How to classify bacteria There are about 1.7 billion organisms To study they must be separated (organisms) into groups. Diversity – because of natural selection (survival) of stronger traits more suited for environmental Similarity – is due to relatedness, this comes from evolution Taxonomists They group organisms into categories called taxa. Look for things like: Growth requirements Morphology DNA Systematics or phologeny is the study of evolutionary history of organisms 1735 Carolus Linnaeus Introduces system of kingdoms Animal or plants 1800 kingdom protesta Animal, plants, fungi, algae, bacteria 1950s fungi get their own kingdom 1969 five kingdoms Animals Plants Fungi Protist Monera 1978 Woese things there should be one more level above kingdom, meaning domains. Kingdoms now into three domains. Domain Animalia Plantae Fungi Protista Eukaryea Monera, bacteria and archaea bacteria Domain bacteria Prokaryotes Archaea = also prokaryotes without peptidoglycan in cell walls Strange group Very very old RNA from 3.5 million years old Extreme habitats (Thermophilic, acidophiles) None of these are known to cause disease. Domain Eukereya are about 2.7 million years old Phylogenetic tree Organism grouped into taxa based on relationship from common ancestor Info from fossil record Becoming more popular to use rRNA sequencing Happens with bacteria constantly Species – group of organisms that interbreed with each other. They do not breed with other species. Least inclusive to most inclusive heiarchy Individual species – sapien Geneus – homo Family – homindae Order – primates Class – mammalia Phylum – chordata Kingdom – animalia Domain – eukarya Most to least is the most common way we see it. Did, Kara, play, cards, or family, games, Saturday Scientific Nomenclature Every organism is given two names (Binomial) Genes Species Used by scientist worldwide, so they known exactly what it is, regardless of what language you speak. Most based in Latin. Suffix for orders = ales For family = aceae In italic or underlined. Whole name then can be abbreviated. Classifying and identifying organisms Go to source – Bergy's manual of Detemitive Bacteriology 1923 was gold standard for lab ID of organisms Based on biochemical tests Can microbe ferment (fermentation abilities) Carbon source Enzymes produced Gram stain results What we do in class 2nd edition of Bergy’s manual of systems of archaea and bacteria Based largely on differences in rRNA sequences What bacteria you can have single strain or subset Chapter 11 Phylogenetic tree Proteobacteria Phylum Most of these are gram negative 5 groups Alpha Beta Gamma – biggest Delta Epsilon These are based nucleotide sequences, also on rRNA Alpha proteobacteria – oligotrophs – they live in environments low in nutrients. Found in deep oceans, deep soil, glacier ice. Makes nitrogen for other life forms Beta proteobacteria – Eutrophs – they live in nutrient rich environments. They like nitrogen and phospherous Gamma proteobacteria – most divers – this includes aerobic and anaerobic organisms Human pathogens Delta proteobacteria – mostly aerobic and gram negative. Many are important for sulfur cycle. Epsilon group – large group of gram negative, curved or spiral rods. Very fastidious *drama queen Alpha Genus Chlamydia: obligatory intracellular bacteria also an STD. Some species cause chlamydia, trachoma and pneumonia Rhizobium: this is nitrogen fixing organism. Will be found in soils. It forms symbiotic relationships legumes. (clover, alfalfa, beans) Rickettsia: obligate intercellular parasite. Transmitted by ticks. This is the cause of rocky mountain spotted fever. Can also cause Typhus. Beta Bordetella – aerobic – very fastidious Neisseria – requires moisture, high concentrations of CO2. Generally pathogenic. They can cause meningitis (bacterial or viral) can also be gonorrhea – can grow on chocolate agar. Gamma Largest and most diverse group. They have almost every shape and arrangement of cells. They have various metabolic and reproductive strategies. This is why its hard to study this group. Ribosomal studies are done, there are five subgroups. Purple sulfur bacteria Obligate anaerobes. They oxidize hydrogen sulfide to produce sulfur granules instead of O2. Don’t need oxygen. Found in hot springs, and stagnant water. Intracellular pathogens – facultative intracellular parasites. They can grow, reproduce inside and outside of hot cell. Genus Legionella – difficult to grow. Common to find in water, streams, water systems (air conditioning systems, hot water tanks, and hot tubs) Species L. pneumophilia – primarily human pathogen. It causes Legionaries disease. Spreads through water droplets. Named after vets attending a conference. 25 of them died. Was found in the air conditioning units. Coxiella burneti – obligate parasite – causes Q fever. Also known as zoonosis – can catch from animals. Humans infected by contaminated aerosols from domestic animals. People at risk are vets, slaughterhouses, farmers, ranchers. Isn’t terrible but feels like milk flu. Can be treated with antibiotics, not necessary though. Methane oxidizers Mathan is a green house gas. These use methane as carbon source. Would be better if we could use these to reduce methane in atmosphere. Facultative anaerobes Three families Enterobacteriaceae (aea = family) (enteric) IMViC – they inhibit intestinal tract of humans and animals. Most of them can ferment glucose. Can produce proteins bacteriocins. Bacteriocins can kill or inhibit other bacteria. Enteric will include: Estcheria, Salmonella, Shigella, Klebsiella, Serratia, proteus, Yersinia, Erwinia, enterobacteria and corynebacteria. Pseudomonads