Chapter 1 Microbiology History BSCI223 Exam 1 Study Guide Leeuwenhoek the first person to discover microbes The only kind of microbe he did not discover was the virus which can only be seen with an electron microscope He began the use of a simple microscope Hans and Zacharias Janssen produced the first compound microscope Hooke noticed the first biological materials cells Linnaeus developed the taxonomy system which is used to name plants and animals and group similar organisms together Hieronymous Fracastorius the first known discussion on contagious infection Agostino Bassi de Lodi described the first case of a microorganism causing a disease a disease affecting silkworms caused by a fungus Semmelweis realized women and children were dying of fevers began the process of washing hands and using bleach to reduce disease Spontaneous generation the idea that living things came from nonliving matter Ex maggots came from meat Redi disproved the idea of spontaneous generation by showing that flies did not come from meat when meat was protected Pasteur used an experimental design with swan neck flasks and controls to boil infusions to investigate spontaneous generation He further disproved spontaneous generation and added to the idea that there are microbes in the air He also proved that bacteria cause fermentation John Snow mapped out where people were getting diseases from certain water sources Lister advocated for disinfection of surgical instruments between patient and cleaning wounds Buchner discovered enzymes and metabolism Industrial microbiology where microbes are used to manufacture products Ex pasteurization in milk cheese alcohol bread antibiotics vitamins laundry enzymes Germ theory of disease the idea that microorganisms are responsible for diseases Pathogen a term used to describe a microorganism that causes a disease Koch helped modify the scientific method to prove that a given pathogen caused a specific disease He also contributed to staining techniques use of Petri dishes lab techniques and sterilization Developed Koch s postulates to show how to prove the cause of any infectious disease Epidemiology the study of the occurrence distribution and spread of disease in humans Jenner invented vaccination and immunity Immunology the study of the body s specific defenses against pathogens Molecular biology concerned with genome sequencing Helps predict evolutionary relationships establish taxonomic categories and identify the existence of microbes that haven t yet been discovered Bioremediation the use of living bacteria fungi and algae to detoxify polluted environments Microbes are also useful for decaying dead organisms and recycling chemicals such as carbon nitrogen and sulfur There are 3 domains of life bacteria archaea and eukarya which are determined by different ribosomal nucleotide sequences Types of Microbial Prokaryotes Bacteria have walls composed of peptidoglycan asexual reproduction most don t cause diseases and are beneficial to our health Archaea have any walls with puesdopeptidoglycan asexual reproduction extreme environments have different rDNA sequences than bacteria Types of Microbial Eukaryotes Algae photosynthetic organisms that can be either multi or unicellular They make their own food from carbon dioxide and sunlight They provide oxygen to Earth Ex seaweed kelp chlorella Protozoa single celled usually capable of locomotion known as the first animals Ex amoeba euglena paramecium Fungi obtain their food from other organisms can be either multi or unicellular usually bare spores Ex molds yeast Overall Role of Microbes Help support all living organisms Nitrogen fixation Replenish oxygen on Earth Degrade organic waste material Help for discoveries about eukaryotic cells We use the fossil record to determine when life began There is evidence that microbes were present as far back as 3 75 billion years ago The first microbes no longer exist They grew in the absence of air in very high temperatures Microbes are typically indestructible Bacteria are versatile and adaptable Can grow at high temperatures different salt contents various levels of pressure and all different pHs Bacteria have evolved ways to live in environments that we cannot They are not simple They are the most prevalent life form on Earth The make up more biomass than any other life form There are more microbes on in the human body than cells Chapter 4 Microscopy We use micrometers um to measure the size of cells Microscopy is concerned with Wavelength the human eye sees visible light through the electromagnetic spectrum Magnification the apparent increase in size of an object Resolution the ability to distinguish between objects that are close together Contrast the differences in intensity between two objects or the object and its background Bright field microscope used for visualization of stained specimens includes a compound microscope which is what we use in the lab Arm supports the body and is the part to grasp when carrying the microscope Body tube connects the ocular lens with the nosepiece Nosepiece rotating part to which the three objective lenses are Objectives lenses that magnify images 4x 10x 40x 100x The 100x objective uses oil immersion to view a specimen Ocular lens lens that magnifies the real image another ten attached times Stage supports the microscope slide Condenser concentrates the light before it passes through the specimen Iris diaphragm regulates the amount of light entering the condenser Coarse adjustment brings the specimen into initial focus Moves the stage up and down Fine adjustment brings the specimen into final focus Dark field microscope used for viewing live unstained specimens that are motile or have an unusual shape Phase contrast microscope uses light for viewing live specimen that would be damaged or altered by attaching them to slide or staining them Electron microscopes helps distinguish structures that are smaller than 200 nm Provide a detailed view of the smallest bacteria viruses cellular structures and molecules Transmission electron microscope TEM reveals much of the internal details not visible through light microscopy Shoots a beam of electrons that produces an image on a fluorescent screen Can t view whole specimens Scanning electron microscope SEM three dimensional and realistic images of whole specimens only magnifies the external surface of a specimen Staining used to help view colorless organisms and create more contrast between structures