Microbes in Our Lives Microorganisms are organisms that are too small to be seen with the unaided eye. “Germ” refers to a rapidly growing cell.

WHY STUDY MICROBIOLOGY Public Health Applications Food Applications Industrial Applications Biofuels Applications Biopharmaceutical applications

Microorganisms Decompose organic waste Are producers in the ecosystem by photosynthesis Produce industrial chemicals such as ethanol and acetone Produce fermented foods such as vinegar, cheese, and bread

Scientific Names Are italicized or underlined. The genus is capitalized and the specific epithet is lower case. Are “Latinized” and used worldwide. May be descriptive or honor a scientist.

Scientific Names Staphylococcus aureus Describes the clustered arrangement of the cells (staphylo-) and the golden color of the colonies (aur-).

Scientific Names Escherichia coli Honors the discoverer, Theodor Escherich, and describes the bacterium’s habitat–the large intestine or colon.

Bacteria Prokaryotes Peptidoglycan cell walls Binary fission For energy, use organic chemicals, inorganic chemicals, or photosynthesis Figure 1.1a

Viruses Acellular Consist of DNA or RNA core Core is surrounded by a protein coat. Coat may be enclosed in a lipid envelope. Viruses are replicated only when they are in a living host cell. Figure 1.1e

Fungi Eukaryotes Chitin cell walls Use organic chemicals for energy. Molds and mushrooms are multicellular consisting of masses of mycelia, which are composed of filaments called hyphae. Yeasts are unicellular. Figure 1.1b

Modern Developments in Microbiology Bacteriology is the study of bacteria. Mycology is the study of fungi. Parasitology is the study of protozoa and parasitic worms. Recent advances in genomics, the study of an organism’s genes, have provided new tools for classifying microorganisms.

Modern Developments in Microbiology Immunology is the study of immunity. Figure 1.4 (3 of 3)

Modern Developments in Microbiology Virology is the study of viruses. Recombinant DNA is DNA made from two different sources. In the 1960s, Paul Berg inserted animal DNA into bacterial DNA and the bacteria produced an animal protein. Recombinant DNA technology, or genetic engineering, involves microbial genetics and molecular biology.

Bioremediation Bacteria degrade organic matter in sewage. Bacteria degrade or detoxify pollutants such as oil and mercury. UN 2.1

Biological Insecticides Microbes that are pathogenic to insects are alternatives to chemical pesticides in preventing insect damage to agricultural crops and disease transmission. Bacillus thuringiensis infections are fatal in many insects but harmless to other animals, including humans, and to plants.

Modern Biotechnology and Genetic Engineering Biotechnology, the use of microbes to produce foods and chemicals, is centuries old. Genetic engineering is a new technique for biotechnology. Through genetic engineering, bacteria and fungi can produce a variety of proteins including vaccines and enzymes.

Modern Biotechnology and Genetic Engineering (continued) Missing or defective genes in human cells can be replaced in gene therapy. Genetically modified bacteria are used to protect crops from insects and from freezing.

Microbes and Human Disease Bacteria were once classified as plants giving rise to use of the term flora for microbes. This term has been replaced by microbiota. Microbes normally present in and on the human body are called normal microbiota.

Normal Microbiota Normal microbiota prevent growth of pathogens. Normal microbiota produce growth factors such as folic acid and vitamin K.

Infectious Diseases When a pathogen overcomes the host’s resistance, disease results. Emerging infectious diseases (EID): New diseases and diseases increasing in incidence.

Exam Questions Definitions Differentiate cell walls of Gram +ve & Gram –ve bacteria Prokaryote Vs Eukaryote Nutrition, environment, staining

Chemical Constituents Bacterial Membrane Structures Structure Chemical Constituents     Plasma Membrane     Phospholipids, proteins, enzymes for energy, membrane potential, transport.     Cell Wall             Gram +ve Bacteria           Peptidoglycan     Glycan chains of GlcNAc and MurNAc cross linked by peptide bridge.           Teichoic Acid     Polyribitol phosphate or glycerol phosphate cross linked to peptidoglycan.           Lipoteichoic Acid     Lipid linked teichoic acid.        Gram -ve Bacteria     Thinner version of that found in Gram positive bacteria.           Periplasmic Space     Enzymes involved in transport, degradation, and synthesis.           Outer Membrane     Phospholipids with saturated fatty acids.              Proteins     Porins, lipoprotein, transport proteins.              LPS     Lipid A, core polysaccharide, O antigen.     Other Structures        Capsule     Polysaccharides (disaccharides and trisaccharides) and polypeptides.        Pili     Pilin, adhesins.        Flagellum     Motor proteins, flagellin.     Proteins     M proteins of streptococci (for example). Bacterial Membrane Structures

Functions Of The Bacterial Envelope Component(s)    Structural Rigidity    All.    Packaging Of Internal Contents    Permeability Barrier    Outer membrane or plasma membrane.    Metabolic Uptake    Membranes and periplasmic transport proteins, porins, permeases.    Energy Production    Plasma membrane.    Adhesion To Host Cells    Pili, proteins, teichoic acid.    Immune Recognition By Host    All outer structures.    Escape From Host Recognition    Capsule, M protein.    Antibiotic Sensitivity    Peptidoglycan synthetic enzymes.    Antibiotic Resistance    Outer membrane.    Motility    Flagella.    Mating    Pili.    Adhesion