Welcome to Microbiology 1

1. Welcome to Microbiology 1 • Introduction to microbiology • Types of Microorganisms • Taxonomy • Historical Perspective of Microbiology and the Golden Age of Microbiology • Microbes and human disease

2. What is Microbiology • Microbes or microorganisms are minute living things that are usually unable to be viewed with the naked eye • What are some examples of microbes? • Bacteria, fungi, protozoa, algae, viruses are examples • Some are pathogenic “germ” refers to a rapidly growing cell

3. Uses of Non Pathogenic Microbes • Microbes • Decompose organic waste • Are produces of oxygen in the ecosystem • Food technology – beer, wine, cheese, bread all fermentation processes • Industrial technology – produce industrial chemicals such as ethyl alcohol and acetone • Genetic engineering • Bioremediation

4. Pictures of Microbes

5. Impact of Microbes on Earth • Ubiquitous • Only form of life for over half of earths entire history so show them some respect • Humans have co-evolved with microbes • In earth’s early history microbes were responsible for creating an oxygen based atmosphere

6. Evolutionary Timeline

7. Evolution • The oldest known fossils are prokaryotes, such as bacteria 3.1billion years old • So these organisms have been around for a while • Using today as a reference point what do you think a million days ago was? • 731 B.C. • My point is that the evolutionary time line is difficult to comprehend

8. A Sampling of Early Life Bangiomorpha pubescens Sexually Reproducing red Alga 1.2 byo Stromatolites with layers of Cyanobacteria abundant 2.7 bya Prokaryotic cells 3.5 byo

9. Size Matters

10. Prokaryotic vs. Eukaryotic • Prokaryotic cells • No nucleus • No membrane bound organelles • Cell wall • Mode of transportation • Eukaryotic cells • Nucleus • Membrane bound organelles • Usually no cell wall – exception fungi • Where do viruses and prions fit into this picture

11. a Bacterial cell (prokaryotic) cytoplasm DNA plasma membrane Prokaryotic Cell

12. Eukaryotic Cell

13. Viruses

14. Viruses

15. Classification of Microbes

16. Terminology in Micro Bio • Eukaryotic Species • A group of closely related organisms that breed among themselves • Prokaryotic species • A population of cells with similar characteristics • Clone population of cells derived from a single cell • Strain genetically different cells within a clone • Viral Species • Population of viruses with similar characteristics that occupies a particular ecological niche

17. Terminology in Micro Bio • Species – a collection of bacterial cells which share an overall similar pattern of traits in contrast to other bacteria whose pattern differs significantly • strain or variety – a culture derived from a single parent that differs in structure or metabolism from other cultures of that species (biovars, morphovars) • Type – a subspecies that can show differences in antigenic makeup (serotype or serovar), susceptibility to bacterial viruses (phage type) and in pathogenicity (pathotype)

18. Major Microbes Studied In Microbiology 1 • Archae Bacteria • Eubacteria • Fungi • Molds • Yeast • Protazoans • Virues and Prions • Helminths

19. Archaea Bacteria • Modern archaea still live in the remaining habitats on the earth that resemble harsh ancient conditions • Often called extremophiles • Methanogens • Halophiles • Hyperthermophiles • Have adapted to multiple combinations of heat, salt, acid, pH, pressure, and atmosphere • Evidence is accumulation that they are actually more closely related to Eukarya than Bacteria because they share a number of rRNA sequences

20. Eubacteria • Three Basic Shapes • Rods, cocci, spirelle • Gram negative or gram positive • Only a small percentage are pathogenic

21. Algae • Are single celled microscopic organisms but some marine algae are large complex organisms • Eukaryotic • All algae photosynthesize their own food • Important source of food for other organism • Only one of medical importance – Prototheca having lost its chlorophyll

22. Examples of Autotrophic Algae

23. Fungi • Fungi are organisms whose cells are eukaryotic • Differ from plants because they are not autotropic • Differ from animals because they have a cell wall • Microscopic Fungi include • Molds • Yeast

24. Molds • Molds are typically multicellular organisms that grow as long filaments called hyphae • Hyphae interwine to make up the body of the mold • Reproduce sexually and asexually by spores • Penicillium chrysogenum – mold which produces penicillin

25. Yeast • Unicellular and typically oval to round • Reproduction asexually by budding and sexually with spores • Saccharomyces cerevisiae causes bread to rise and produces alcohol from sugar • Candida albicans causes yeast infections in women

26. Examples of Molds and Yeast Saccharomycescerevisiae Penicilliumchrysogenum

27. Protista • Single eukaryotic cells • Subcellular organelles • Food vacuoles • Contractile vacuoles • Plant like • Fungi like • Animal like

28. Example Protazoans Amoeba Paramecium Trypanosomabrucei

29. Viruses • Living and non-living • Acellular • DNA or RNA as genomes • Budding or lytic life cycles

30. Classification of Microbes • Taxonomy – classification of microbes • The science of classifying organisms • Provides universal names for organisms • Provides a reference for identifying organisms

31. Classification of Microbes • Taxonomy • Systematics or phylogeny • The study of the evolutionary history of organisms • All species inventory (2001-2025) • To identify all species of life on earth

32. A History of Phylogenetic Trees • First contained two kingdoms • Plants and animals • Eventually a third kingdom was added • Protista • Finally Whittaker proposed the fourth kingdom for bacteria and a fifth kingdom for fungi

34. Taxonomic Scheme • Initially protozoans and various other relatively simple organisms have been placed in a heterogeneous grouping • Kingdom Protista • Such a lumping of disparate groups is artificial due to the lack of phylogenetic evidence • Goal of taxonomy is to reflect as accurately as possible evolutionary affinities • Much new molecular biological data is reshuffling some classifications

35. Different Taxonomy Systems

36. Leedale Classification Scheme • Kingdom Protista is abandoned • Now four kingdoms • Leedale’s system assigns each of the various protistan taxa to one of the three major kingdoms to which it is most closely related • All autotrophic protists are plants • Slime molds are fungi • Protozoans belong to animalia

37. Leedale’s Four Kingdom Approach • Places unicellular organisms with the multicellular groups with which they appear to have the closest evolutionary relationship • More accurately reflects phylogenetic affinities

38. Yet Another System - Woese

39. Classification of Microbes

40. Taxonomic Hierarchy Taxonomic Hierarchy Domain Kingdom Phylum Class Order Family Genus Species Dumb Kings Play Chess On Funny Green Squares

41. Sample Taxonomy

42. Binomial system of nomenclature Taxonomic Hierarchy Domain Kingdom Phylum Class Order Family Genus Species Binomal Nomenclature uses the Genus and Species name to identify each creature.

43. Binomial Nomenclature • Each name is derived from Latin • Specific way to write each name • The first word is capitalized • Name is in italics • After the name has been written out once completely in a scientific paper the genus name may be abbreviated • Staphylococcus aureus • S. aureus

44. History of Microbiolgoy • First microbes were observed in 1673 • In 1665 Robert Hooke (English) reported that living things were composed of little boxes or cells

45. First Microscope 1673-1723, Antoni van Leeuwenhoek (Dutch) described live microorganisms that he observed in teeth scrapings, rain water, and peppercorn infusions.

46. Spontaneous Generation • Many believed in spontaneous generation • Life can arise from non-living matter Aristotle 384-322 B.C. • 1668 Italian physician Francesco Redi performed an experiment to disprove spontaneous generation • How could you disprove spontaneous generation by experimentation

47. Redi’s Experiment

48. Redi’s Experiments Redi filled six jars with decaying meat.

49. Biogenesis • Rudolf Virchow (German) presented a hypothesis of biogenesis • Biogenesis – living cells can only arise from preexisting living cells • Louis Pasteur was instrumental in disproving spontaneous generation

50. So now there are two hypotheses: The hypothesis that living organisms arise from nonliving matter is called spontaneous generation. According to spontaneous generation, a “vital force’ Forms life. The Alternative hypothesis, that the living organisms arise from preexisting life, is called biogenesis.