BIO 326R 1st Edition Lecture 25 Outline of Last Lecture I. Endosporesa. Resistanceb. Mxyococcusc. siderophoresOutline of Current Lecture I. Siderophoresa. IronII. Heterocystsa. Cyanobacteriab. Endosymbiotic theoryIII. Biofilmsa. Polymeric matrixb. Dnase treatmentIV. Archaeaa. Bacteria vs. archaea vs. eukaryaCurrent LectureSiderophores- Secreted outside the cell- Bind Fe3+o Nearly all bacteria need iron to liveo Very limiting element—not very accessible Ex: bacteria that live in the human body—the body has lots of iron but it is mostly bound up by oxygen in hemoglobin- small molecules secreted by a bacteria that bind iron with a high affinityo only Fe3+ (not 2)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.- receptors in the outer membrane that uptake iron for the siderophore (see Fe Transcportslide for an image and more details)o bacteria does this in low iron conditions, like in the human body- costs energy to bring Fe3+ into the cell- need iron because it serves as an enzyme cofactor for several cell process such as respirationo carries electrons well- some bacteria evolve their own receptors to use other bacteria’s siderophoresHeterocysts- cyanobacteriao photosynthetic bacteria, blue-green algae- main contributors to changing the Earth’s atmosphere to an oxidizing one through CO2 fixation and photosynthesis- endosymbiotic theoryo idea that chloroplasts came from cyanobacteria and mitochondria came from proteobacteria (Rickettsiales)o cyanobacteria and proteobacteria were taken up by eukaryotic cells and evolved within into chloroplasts and mitochondria, respectively, and formed a symbiotic relationship the relationship between chloroplasts and cyanobacteria and mitochondria and proteobacteria was discovered using a dendogram- heterocysts are made by cyanobacteriao fix nitrogen—nitrogenase is an issue (just as for Rhizobia) doesn’t work in O2 conditions and the cell is photosynthetic (liberates oxygen), so they can not exist together- differentiation of vegetative (normal) cells into heterocysts allows to fix nitrogen anaerobically while maintaining oxygenic photosynthesis- heterocysts don’t do photosynthesis anymoreo how can it grow? The vegetative cells feed the heterocysts carbon in the form of glucoseo heterocysts feed vegetative cells fixed nitrogen- heterocysts are terminally differentiatedo cannot revert back to normal cell- produced/spaces evenly every 10-12 cyanobacterial cells- add three membranes to vegetative cello reduces oxygen uptakeBiofilms- exopolymeric matrixo can be polysaccharide or proteino also includes DNA—important medical discovery prevalent in ALL biofilms if you treat with dnase, they dissolve- Dnase= human enzyme that degrades DNAArchaea Domain-- ComparisonBacteria Archaea Eukarya Size 1-4 microns 1-4 microns >5 micronsMembrane bound nucleusNo No YesOperons Yes Yes NoCell wall and componentsPeptidoglycan—muramic acid (NAG and NAM)Pseudopeptidoglycan—NAG but no NAM (GlcNac but no muramic acid)No PG—NAG but no NAM (GlcNac but nomuramic acid)Lipids Ester-linked Ether-linked Ester-linkedCell membrane Bilayer Single layer—two heads connected by same tailsbilayerRNAP Simple Complex (more subunits)Complex (more subunitd)ribosome 70s—chloraphenicol sensitive (antibiotic that inhibits protein synthesis)70s—chloraphenicol insensitive80s—chloraphenicol insensitive - No discovered pathogenic archaea- Many extremophileso Ex: can survive at 120 degrees Celsius—temperature that we sterilize at Use iron as an electron acceptor- Methanogenso Live in cowso Produce methaneo Reduce CO2o Obligate
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