Microbes effect on the planet is found in carbon nitrogen cycling disease pathology food use as model organisms industrial applications What is Microbiology study of microbes prokary bacteria and archeae euk algae protozoa fungi Lecture 2 Size need electron microscopy to see virus Prok all cell life have ribosomes cytoplasm fluid that ribosomes suspended in nucleoid circular DNA no membrane inclusions for energy stores magnetic material to orient it no membrane not in all microorgs cell wall structural rigidity not for permeability barrier cell membrane lipopolysacc layer outer membrane permeability barrier in some flagellum pili fimbriae extend from cell Euk DNA in nucleus Ribosomes on ER protein synthesis sim in structure and function Nuclear pores Lysosomes secretory vesicles cell walls composition is different Mitochondria energy generating organelle cilia move fluid substrate across surface of cell not related to prok flagella fimbria pili prok and euk flagella are different Germ Theory 1546 Fracastorius On Contagion syphilis typhus 1835 Bassi de Lodi fungus disease on silkworm 1st microorg recognized as contagious animal disease 1847 Semmelweis wash hands in bleach reduced fever doctors transfer disease from cadaver to patient b c they didn t wash hands 1854 Snow Cholera outbreak 1860 Pasteur sterilized broths inoculate to grow bacteria not spontaneous growth 1870 Lister disinfect surgical instrument and clean wounds 1890 Koch create pure cultures Koch s postulate suspected organism present in all cases of disease and absent from healthy grow suspected in pure culture all same microorgs isolated colonies using streak technique inoculate healthy animal with suspected cells if animal healthy this is not disease causing microbe if animal gets disease reisolate organisms and show that it is the SAME as culture grown before method that can be applied to many areas of research Microscopy 1590 Janssen made first compound microscope 1660 Hooke detailed observations drawings 1676 Leeuwenhoek first to observe microorgs saw them move bend shape Microbe microscopic life forms usu only seen w microscope 1mm 0 1um to 1000 um Electron microscopy light mic limits resolution b c of visible wavelengths TEM flat appearance see lots of detail in cell separation b w membrane and wall bright dark spots nucleus parts SEM 3D pictures sim resolution to TEM Light microscope can see euglena RBC bacterial cells but NOT viruses too small Lecture 3 Human cell 10 um diameter Ribosomes present Cytoskeleton supports in all Centrioles in animals Have membranous organelles Prok v Euk 1 um length diameter Ribosomes present Cytoskeleton gives shape in some No centrioles No nucleus ER golgi lysosomes peroxisome vacuole vesicles mitochondira chloroplast No cilia Some have fimbriae and pili Cytoplasmic membrane lacks carbs and sterols CM has glycolipids glycoprotoines sterols Cytosol Endospores in some Small ribosome 70s Single circular chromosomes w o histones Inclusions in most Cytosol No endospores Large ribosome 80s Multiple linear chromosomes w histones Inclusions in some Some have cilia No fimbriae and pili Grouping organisms taxonomy longer the branch on phylogenetic tree farther they are away from each other more evolutionary distance more changes made to 16s RNA Systematic Microbio compare to known groups in est classification place in appropriate group all bacteria referred to according to binomial nomenclature Genus species report characteristics in Bergey s Manual encyclopedia of species Morphology of prokaryotes Coccus spherical cells Coccobacillus short rods Bacillus rod shaped Vibrio curved rod shaped Spirillum spiral Spirochete thinner spiral move by twisting way through environment corkscrew Pleomorphic shape not regular observed as being characteristic of microbe Lecture 4 Seeing things under microscope pigmented things easy to see contrast against background stains bind to charged molecules create contrast from background types 1 simple flood slide w stain cells take up stain 2 complex differential use 1 reagent steps dyes to stain Example gram stain tells about cell wall structure endospore stain Gram Stain differential differentiate based on peptidoglycan Gram positive thick PG gram negative thin PG and an outer membrane some do not stain steps 1 flood heat fixed w crystal violet all cells purple 2 add iodine solution all cells stay purple 3 decolorize w alcohol gram are purple gram are colorless 4 counterstain w safranin G purple G pink red Peptidoglycan made of NAG N acetalglucosamine NAM N acetalmuramic acid repeating in a backbone linked by beta 1 4 linkage NAM NAG strands wrap around cell outside cytoplasmic membrane to add strength strands cross link attach tetrapeptide as crossbridge Gram positive cell wall teichoic acid attached to phospholipid bilayer some not attached attached to PG cell wall instead are polymers of phosphates and carbons glucose AA cell wall can have proteins that take up nutrients make cell wall Gram negative cell surface thinner PG and one more layer than g periplasmic space b w outer and cytoplasmic membrane 2nd permeability barrier called outer membrane outer membrane has lipid sugar LPS decorations extending from it and recognizes microorgs porins in PG cell wall allow things to pass lipid bilyaer permeability barrier under cell wall PG is great target for antibotics b c all cells have PG G less affected by penicillin b c of the outer membrane that serves as a permeability barrier penicillin is kind of big molec so won t cross as easily needs to be transported G more affected b c outside is the PG Cell walls function in maintaining cell shape giving rigidity attachment sites for proteins do NOT prevent small molecules from entering cytoplasm Mycobacteria bacterial gram exception long chains of C molecules waxy substance on cell layer that prevents dye from absorbing won t see anything with gram stain Archaea bacterial gram exception cell walls are pseudomurein some can be stained w gram stain reagents but outcomes don t correspond to cell wall structure like it does with typical bacteria have S layer crystallized proteins on surface that provide another barrier b w org and environ Endospores gram exception differentiated bacterial cell type process sim to cell division 1 DNA replicated 2 DNA aligns along axis 3 CM invaginates to form forespore 4 CM grows engulfs forespore w in 2nd membrane vegetative cell s DNA disintegrates 5 cortex deposited b w membranes