EBIO 3400 1st Edition Lecture 6Outline of Last Lecture I. Prokaryotic cell structure Outline of Current Lecture II. Pelagibacter vs. E. ColiIII. The flagella motorIV. Gram - vs. gram +V. Chemotaxis VI. Storage GranulesVII. Archaea Current LecturePelagibacter:Common bacteria of the oceanImmobile Food being diffused to them Moves around in a random way: random walkBrownian motion: (random motion of particles suspended in a fluid)_________________________________________________________________________________E. ColiWell mixedHoward burg built the special microscope where you can track an individual cellSwim: with extremities spread out then all flagella are all in sync Random walk These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.What leaks out of human cell falls into beaker of E. coli and what happens to the E. Coli: Sugar, amino acidsE. Coli senses chemicals filling up his receptors swims longer in that direction, if senses the receptors are less full then will tumble (spread flagella rotation clockwise to counterclockwise) until find a direction that increases those receptors random walk Food: anything dying or falling in its experiment chemotaxis: way they sense their environment and behavior of how they respond to the bad and good energy sources (toward if good, away if bad) Biased random walk: less random disruptions, more toward the attractant I. The flagella motorComponentsA. Rotor= motor spins forces that translates through the shafB. Rings= bearings reduce friction, so rod can really spin and do the work on the outsideC. Rod= Shaf, does the rotation/spinning, propels forward II. Gram - flagella motor compared to gram +A. Gram - needs more support than gram + due to the thinner peptidoglycan layerso need bearings at each layer, more protective III. Chemotaxis Definition: movement of bacterium in response to chemical gradients A. Attractants cause a CCW rotation i. Flagella bundle together push cell forward  “run”B. Lower concentrations of attractants causes CW rotationi. Flagella bundle falls apart  “tumble”= bacterium briefly stops, then changes direction C. Random walk: caused by the alternating runs and tumbles i. Receptors detect attractant concentrations: sugars, amino acidsD. Biased random walk: Attractant concentration increases and prolongs run i. Causes a net movement of bacteria toward attractants (or away from repellents) IV. Spirochetes and there flagella structure A. Perplasmic flagella: rotary motor, their flagella (polar) are continued in periplasmic space in the organism wrap around they body between the cell wall and outersheathin a very tight fashion.Force translated along the whole body resulting in whole body rotation, move in very viscous (thick) environments i. A lot of them are anaerobic (live in mud), or pathogens ii. Very powerful bacteria V. Storage granules (a type of inclusion)Bacteria have the ability to store stuff in the cytoplasmA. Some are membrane bound, most aren’t B. Used for storage:- Carbon compounds and energy sources - Inorganic substances C. Fat storage (poly-beta-hydroxybutrate) in cytoplasm D. Sulfur granuoles in Beggiatoa- If the cell runs out of H2S it can oxidize the Sulfur to sulfuric acid- Stores sulfur and eats it later, not the best appetizing because it produces sulfuric acidE. Thiomargaritanamibiensis are not gram + bacteria but use H2S as an energy source and nitrate as an electron acceptor - As big as a fruit fly- So big because as much as 98% of their cell is filled up with a vacuole filled with nitrate - Eat their stored sulfur later using nitrogenF. MagnetosomesMembrane bound magnetic inclusions A. Linear inclusion that are basically magnets inside the cells B. Made from magnetic minerals C. Sense magnetic fields and follow these magnetic fields G. Magnetotactic BacteriaDiscovered by R.P Blakemore in 1975 Habitat: Live in low oxygen zones and sediment-water interface; found in fresh waters and marine environments around the world Rods, vibrioid, coccoid, or helical Polar flagella  Move geomagnetic north in northern hemisphere and geomagnetic south in southern hemisphereA. Magnetosome formation  Magnetosome particles are made of either magnetite (Fe3O4) or greigite (Fe3S4) Vesicle membranes / lipid bilayer Microaerobic conditions are required; generally non-magnetic when grown aerobicallyVI. Archaea 3 main classes: Euryarchaeota, Thaumarchaeota, CrenarchaeotaOfen though as extremophiles (but most are not) some don’t even have cell walls Similarities to bacteria  Archaea have generally the same shape, size, and appearance as bacteria. Most Archaea multiply by binary fission and move primarily by means of flagella. Phenotypic characters (micro-morphological and biochemical) can be used to distinguish the Archaea from the Bacteria and EucaryaA. Archaea membrane lipidsi. Have ether bonds instead of ester bonds ii. Have no fatty acids (unlike bacteria and Eucarya) and instead have side chains composed of repeating units of isoprene iii. The hydrophilic (charged group) on their membrane lipids can be many things other than phosphate (e.g. sugars, sulfate)B. Archaeal cell walls- No peptidoglycan - Have various types of cell wall including proteins, polysaccharides, glycoproteins, or pseudopeptidoglycan C. Similarites to eukaryotes- Archaea have more complex RNA polymerases than Bacteria, similar to Eucarya and histones that are similar to Eucarya.D. Metabolic differences• Archaea are extremely metabolically diverse• Archaea do not use the glycolysis pathway• Many archaea do not have functional Kreb’s cycle pathways- Many pathways and enzymes are only found in the Archaea, will be discussed such asmethanogenesis and other pathways laterD. Euryarchaeota- Occupy may different niches and have large diversity of metabolic types- Include the methanogens, the extreme halophiles and many extreme thermophiles (many use sulfur metabolism)- Best studied group of archaea: methanogens (make methane gas)A. Extreme Halophilic Euryarchaea- Require at least 9% NaCl for growth, may tolerate near saturation - 32%- Found in Dead Sea, Great Salt Lake, Heavily salted foods - Some can’t live without