EBIO 3400 1st Edition Lecture 3Outline of Last Lecture I. History of MicrobiologyOutline of Current Lecture II. History of PlaguesIII. Doctor influenceIV. Microbes in NatureV. Microbial Evolution and classificationVI. Molecular SystematicsCurrent LectureI. How plagues were thought to have spreada. Plague spreads rapidly because it blocks flea digestion – flea can have a blood meal but still feels starved and will jump from host to hostb. Throughout history, plague killed >200 million peoplec. Largely disappeared from Europe in the 19th century because better public healthunderstanding and doctors starting to figure out that microorganisms caused diseases so there were more effective quarantines d. Black rats replaced by brown ratsover a 200 year period so less susceptible to plaque than black ratse. People who survived the black death, a bigger population is probably more resistant than othersf. On microbes sideg. If wipe out all hosts then end up going extinct yourselfh. Goal as a pathogen is to reproduce, spread, and carry oni. Most human cases in the United States occur in two regions: 1) northern New Mexico, northern Arizona, and southern Colorado; and 2) California, southern Oregon, and far western Nevada. Plague also exists in Africa, Asia, and South AmericaII. Tyndallizationa. Named after Irish doctor John Tyndall (1820-1893)b. Was used to sterilize hard-to-sterilize liquids; traits of endospores to kill them because many endospores are heat activated - Boil for 20 minutes, cool overnight, boil again then repeat as neededc. Why does this work? 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.- Because many endospore formers (many Firmicutes, e.g. Bacillus and Clostridium spp.) have heat-activated endospores- That is they germinate after exposure to heat or other stresses- Goal: The first boiling of the process wakes up the endospore then cool to germinate (grow or vegetate) then susceptible to heating so boil again to kill them when in vegetative state then let it cool down so they can live and grow and boil them again before they grow new endospores -Phylum of bacteria: firmicutes found in some soils III. Robert Koch (1843-1910)a. German rural doctorb. In his spare time, he began to study anthrax - a disease of cattle and sheep and sometimes peoplec. He noticed “threads” in the blood of dead cattle- They were the bacilli that were the cause of the disease - but no one had proven it- Threads that have vegetative cells and forming endosporeswhich are linked to the disease- Healthy animals didn’t have the bacilli in their blood so he began to experiment with mice by injecting blood from sick cows into themd. Results:- The mice got sick and when he looked at their blood underthe microscope, he found the bacilli- To prove that the bacteria grew inside the mouse he put some blood from a sick mouse into the aqueous humor form an ox’s eye (sterile media) and the bacilli began to multiply!- Koch continued to keep this “culture” of bacilli growing, every day repeating his experiment by adding a tiny bit (dilution) of the infected drop into a new sterile one- After eight days, he took a drop of this culture - one that had not been inside a mouse, and injected it into a fresh, healthy mouse and the mouse was dead the next dayKey point: Could keep them growing over time in the sterile culture Koch and his potulates: 1) The disease organism must be present in sick animals and not present in healthy ones2) The organism must be cultivated (isolate) pure culture away from the patient’s body3) This culture, when inoculated into a healthy animal should produce the characteristic symptoms of the disease4) The organism can be re-isolated from these animalsIV. Fannie Hessea. Discovered that agar could be used as a solidifying agent for bacteriological media in 1882. - This greatly accelerated the development of MicrobiologyV. Paul Ehrlich and chemotherapya. Noticed bacteria picked up certain stains more readily than did mammalian tissueb. Success was with Salvarsan that killed Trypanosomes and Treponema pallidum. Early chemotherapeutic agents often had nasty side effects. It wasn't until the mid-1900s that very specific antibiotics were developed- Stains are often toxins - If a bacterium picks up these stains but not the human then it will hurt the bacteria andnot the human VII. A. Fleming a. Saw the Zone of inhibitionb. He discovered antibiotic by accident (Penicillium)c. Found a ring around the fungus: was killing or inhibiting the bacteria out VIII. Microbes in naturea. Non-medical Microb. MartinusBeijerinck (1851-1931)- Invented the Enrichment culture technique: use media that is designed to isolate specific metabolic groups from nature (e.g. N2-fixing bacteria and many other discoveries)i. Sergi Winogradsky (1856-1953)a. Winogradsky was the first to describe sulfur oxidizing bacteria such as Beggiatoab. These organisms are chemoautotrophs (fix CO2 without photosynthesis) and use chemicals as their energy sourcec. Sulfur granuoles in Beggiatoa which stores sulfur granules in its cytoplasmd. Eating sulfur and storing it as an extra food source for latere. 1922 Kluyver replaced Beijerinck at the University of Delft and ushered in the modern era of comparative biochemistry. Kluyver and van Niel proposed that all respiratory reactions (aerobic and anaerobic) could be summarized using thesimple formula: - AH2 + B -----> A + BH2For BeggiatoaH2S + O2 -----> So + H2OBeggiatoa is oxidizing H2SH2S is its energy source!Note: All reactions show: Oxidizing something to gain energy - Heterotrophic live by having something reduced combined with mostly oxygen and energy released - Beggiatoa is eating hydrogen sulfide, which is being reduced to water, and Oxygen is being oxidized to SVIII. Microbial evolution and classification - Classifying microorganisms: The grouping of organisms according to distinguishing characteristics that they shareWhy are taxonomy and systematics important? * Basis of all biology: knowing how they are all related to each other 1) Allows information to be organized so it can be easily accessed by all in the scientific community2) By knowing properties and characteristics, we can make predictions about related organisms. (“model organisms”)3) Allows for a common language. Enforces strict rules4)