You must have a long-sleeve lab coat to the knees and safety glasses with peripheral protection RCC Medical Supply th Ave # H103 Greeley, CO (970) % Discount on lab coats (must present student ID)

Humans and the Microbial World Chapter 1

Current Microbial Threats Measles (vaccine preventable) Polio (vaccine preventable) Whooping cough (pertussis; vaccine preventable) Severe acute respiratory syndrome (SARS CoV) Malaria Yellow fever virus West nile virus Tuberculosis Human immunodeficiency virus (HIV; AIDS) Hepatitis C virus Multidrug-resistant Staphylococcus aureus H5N1 Avian Influenza Nipah virus Hospitals

1.1 The World of Microorganisms Spontaneous Generation: Life from nonliving materials Disproved by Francesco Redi in late 1600s Showed that worms which appeared on rotting meat were from fly eggs Disproved again by Louis Pasteur in mid 1800s Showed that appearance of microbes in sterilized media was from air-borne bacteria Showed that sterilized materials remained sterile if kept isolated from the external environment

1.2 Microbiology: A Human Perspective Microorganisms cannot be seen without the aid of a microscope There are more than 200,000 known microbes Exist in virtually any environment that has water Exhibit tremendous biodiversity Compose the largest biomass group of living organisms

Nitrogen fixation: Converting atmospheric nitrogen (gas) to biomolecules (e.g., nucleic acids, amino acids) Oxygen production: Convert carbon dioxide to molecular oxygen (O 2 ) Degradation of organic materials Gastrointestinal tract Sewage treatment plants Vital activities of microorganisms

Food production: bread, beer Bioremediation: decontamination of hazardous wastes Useful products: ethanol fuel, antibiotics, amino acids Genetic engineering: pharmaceuticals, vaccines Genomics: genome sequencing permits understanding of disease mechanisms Applications of Microbiology

Infectious diseases have killed more people than all wars and natural disasters combined Outbreaks have changed the course of history Notable pandemics Spanish Flu ( ): 50 million global deaths Smallpox (middle ages): >100 millions deaths (est.) Plague (1300s-1800s): >100 million deaths (est.) Introduction of European diseases killed 30 to 40 million Native Americans (est.) Vaccines have dramatically decreased the incidence of infectious diseases, especially in children Medical microbiology

Re-emergence of “Old” Infectious Diseases Colorado has one of the lowest childhood vaccination rate in the U. S. Cases of whooping cough have increased in the last few years Many microbes have evolved antibiotic resistance Medical microbiology (cont.)

Emerging infectious diseases As humans encroach upon wild habitat, new infectious agents (microbes) are discovered These agents are typically hosted by animals and are termed zoonotic agents Medical microbiology (cont.) AgentHostDisease Ebola virusBatsEbola hemorrhagic fever SARS virusBatsSevere acute respiratory syndrome Sin Nombre virusDeer mouseHantavirus cardiopulmonary syndrome Nipah virusBatsNipah encephalitis Dengue virusMosquitosDengue fever; Dengue hemorrhagic fever Machupo virusVesper mouseBolivian hemorrhagic fever Avian influenza virusesVarious birdsInfluenza Some recently discovered agents and their animal hosts

1.3 The Microbial World Bacteria Procaryotes (no organelles) Most have rigid cell walls composed of peptidoglycan Archaea Similar to bacteria, but no peptidoglycan Often found in extreme environments (temperature, pH, high salt, etc.)

Eucarya Complex organelles Larger than bacteria and archaea Members Algae (photosynthesis) Fungi (single and multicelluar) Protozoa Nomenclature Genus is capitalized Species is not Both are italicized Example: Yersina pestis

1.4 Viruses, Viroids, and Prions Viruses Not considered living; they are complex macromolecules composed of nucleic acids and proteins (some have lipids) Noninfectious viruses are said to be inactivated; you cannot “kill” a virus (since they are not considered living organisms) Obligate intracellular parasites Tend to be species-specific Reside in a reservoir host in which they cause limited pathology or are chronic Disease usually occurs when the virus “jumps” species Deer mice permanently host Sin Nombre hantavirus without pathology (disease) Humans infected with SNV often develop hantavirus cardiopulmonary syndrome

Viroids Composed of RNA Smaller than viruses Rely on other viruses to replicate Best characterized in plants Prions Composed of proteins only Cause neurological disease, termed spongiform encephalopathy Can be transmitted to humans from some animals (e.g. “mad cow”)