MICROBIO

• Microbiology is the science dealing with the study of organisms that are individually too small to be seen by the naked eye which includes bacteria, fungi, viruses and protozoa.
• Microbiology is the study of microbes.
• Individual microbes can be observed only with the use of various types of microscopes.
• The two major categories of microbes are acellular microbes, also called infectious particles, which include viruses and prions, and cellular microbes, also called microorganisms.
• Carbol fuchsin (Primary stain) 5 min (heat) Acid alcohol (Wash) 15 seconds Methylene blue (Secondary stain) 1 min Acid fast - take up the primary stain (pink) Non acid fast - take up the secondary stain (blue) Stains for Special Structures Endospore stain - demonstrates spore structure in bacteria as well as free spores Capsule stain - demonstrates presence of capsules surrounding cells; also known as negative-staining; e.g., nigrosin or India ink Flagella stain - demonstrates presence and arrangement of flagella Cytoplasmic inclusion stains - identifies intracellular deposits of starch, glyc
• Simple staining procedure involves staining with methylene blue, which is merely used to stain the cells so that their size, shape, and morphologic arrangement can be determined.
• Structural staining procedures include capsule stains, flagella stains, and endospore stain, which are used to determine whether the organism is encapsulated, whether the organism possesses flagella and, if so, their number and location on the cell, and whether the organism is a spore-former and, if so, to determine whether the spores are terminal or subterminal spores.
• Differential staining procedures include Gram stain and Acid-fast stain, which are used to differentiate between Gram-positive and Gram-negative bacteria and to differentiate between acid-fast and non-acid-fast bacteria.
• Even before microorganisms were seen, some investigators suspected their existence and responsibility for disease.
• The Roman philosopher Lucretius and the physician Girolamo Fracastoro suggested that disease was caused by invisible living creatures.
• Heating an infusion to boiling for 10 mins destroys the heat-labile forms or vegetative cells.
• Allowing an infusion to remain at room temperature overnight allows most of the endospores to germinate to form vegetative cells that are easy to kill.
• Synthetic Biology is a field of science that aims to rebuild or create new life forms from scratch by combining different molecules from different species.
• In 2002, State University of New York, Stony Brook reconstructed poliovirus from separate poliovirus genes and proteins.
• In 2003, Craig Venter and his team assembled bacteriophage from “off-the-shelf” biomolecules.
• In 2004, researchers from Rockefeller University created small “vesicle reactors” with a vesicle wall made from egg white and cell contents from bacterial cell stripped of any genetic material.
• Agostino Bassi made the first specific causal association between microorganism and disease in 1834 by proving that a disease in silkworms was the result of a fungus infection.
• Louis Pasteur, known as the “Grandfather of Microbiology,” developed germ theory and conducted experiments that clearly indicated its correctness.
• Joseph Lister, known as the “Father of Antisepsis,” put to practical use the emerging concept that disease and infection were the result of invading microorganisms.
• Frannie Eilshemius Hesse, wife of Koch’s assistant, Walther Hesse, was the first to propose the use of agar to solidify a nutrient medium.
• Richard Petri, one of Koch’s assistants, developed the Petri dish (plate), a container for solid culture media.
• Robert Koch introduced the scientific approach to the field of medical microbiology.
• The earliest microscopic observations appear to have been made between 1625 and 1630 on bees and weevils by the Italian Francesco Stelluti, using a microscope supplied by Galileo.
• About 1674, the invisible world of microorganism was discovered by the Dutch merchant Anton van Leeuwenhoek.
• Leeuwenhoek was a Dutch merchant who used hand lenses to inspect the quality of cloth.
• Leeuwenhoek was inspired by Hooke’s Micrographia, and so he developed the skill of grinding lenses.
• Using only a single lens, no larger than a pinhead that magnified objects 200 x, Leeuwenhoek was able to observe animalcules.
• The Three Domain Classification is based on the similarities in the 16s rRNA sequence and groups all organisms into Three Domains: Bacteria, Archaea, and Eucarya.
• The Three Domain Classification includes the following kingdoms: Protista, Fungi, Plantae, and Animalia.
• The Three Domain Classification also includes the following phyla: Chordata, Ascomycota, and Proteobacteria.
• The Taxonomic Classification of Humans, Brewer’s Yeast and a Common Bacterium is: Human Being, Brewer’s Yeast, Escherichia coli.
• Major characteristics of bacteria include Morphological Characteristics, Chemical Composition, Cultural Characteristics, Metabolic Characteristics, Antigenic Characteristics, Genetic Characteristics, and Pathogenicity.
• Morphological Characteristics refer to cell shape, size and structure; cell arrangement; occurrence of special structures and developmental forms; staining reactions; motility and flagellar arrangement.
• Chemical Composition refers to the chemical constituents of the cell, for example, presence of lipopolysaccharide in cell walls, teichoic acids or capsule.
• Cultural Characteristics include nutritional requirements and physical conditions required for growth and the manner in which growth occurs.
• Metabolic Characteristics refer to the way in which the cells obtain and use their energy, carry out chemical reactions and regulate these reactions.
• Antigenic Characteristics are special large chemical components (antigens) of the cell, distinctive for certain kinds of microorganisms and antibodies are widely used as tools for the rapid identification of particular kinds of microorganisms.
• Genetic Characteristics are characteristics of the hereditary materials of the cells (deoxyribonucleic acid or DNA) and occurrence and function of other kinds of DNA that may be present, such as plasmids.
• Plasmids are circular DNA molecules that are capable of autonomous replication within bacterial cells and presence of this structure indicates the ability of the cell to make toxins (toxigenicity).
• Pathogenicity refers to the ability to cause disease in various plants or animals or other microorganisms.