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Biology Dept

CSU, Stanislaus

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Lecture 1

Microbiology Review Reading: pg. 7-68

• Changing view as to scope and type of diseases

• Prokaryote vs. Eukaryote (fig. 1.1, pg. 7)

• Macroparasites vs. microparasites

• Intracellular vs. extracellular pothogens

• Systems of classification (fig. 1.2, pg. 9)

• Bacteria

o Structure (fig. 2.2, pg. 12)

o Nutrition

o Growth and division (fig. 2.3, pg. 13)

o Gene expression (fig. 2.4, pg. 15)

o Extrachromosomal elements

o Mutation and gene transfer

§ Mutation

§ Gene transfer and recombination

§ Transformation

§ Transduction

§ Conjugation

§ Transposition

§ Survival under adverse conditions

· Viruses

o Infection of host cells (fig. 3.3. pg. 30)

o Routes of entry (fig. 3.4, pg. 30)

o Major groups of viruses

§ Type of nucleic acid

§ Number of nucleic acid strands and polarity

§ Mode of replication

§ Size, structure and symmetry

§ Fig. 3.12, pg. 36-37

· Fungi

o Fig.4.2,pg.40

· Protozoa

o Fig. 5.2, pg. 44

· Helminths

o Fig.6.1,pg.47

· Arthropods

· Prions

· Host-parasite Relationship

o Normal flora (fig. 8.1, pg. 58), (fig. 8.2, pg. 59)

o Symbiotic association

§ Commensalism

§ Mutualism

§ Parasitism

o Evasion strategies (fig. 8.7. p. 65)

Lecture 1: Microbiology Review

p.7-68

Microorganisms

p Bacteria

p Protozoa

p Fungi

p Helminths

p Algae

p Viruses

p Prions

Medical microbiology

p basics of microbial entities and diseases they cause

p 100 bacteria cause disease

n succinct patterns

n depends on the portal of entry

p Infectious diseases

n Everyone is susceptible

Prokaryote vs. eukaryote

p Fig. 1.1 (p. 7)

n No nucleus

n Coupling of transcription and translation

n Cell wall with peptidoglycan

Prokaryote vs. eukaryote

p Fig. 1.1 (p. 7)

n Has nucleus + other organelles

n Several linear chromosomes

n Transcription – nucleus

Translation – cytoplasm (ribosomes)

n No cell wall, if present contain no peptidoglycan

Microparasites vs. Macroparasite

p Differences

n Size

p Micro- viruses, bacteria, protozoa, fungi

p Macro- worms and arthropods

n Replication

p Micro- within host, large numbers of progeny

p Macro- several hosts, few progeny

Intracellular vs. extracellular pathogens

p Intracellular pathogens

n Live only within host cells

n Receive nutrients from host

p Chlamydia, Rickettsia

n Relies on host machinery

p viruses

n Problems for host

Intracellular vs. extracellular pathogens

p Extracellular pathogens

n Live outside host cells

n Digests cells; takes nutrients directly from host tissue (Entamoeba histolytica)

p Allows pathogen to grow, reproduce and move freely within host tissue

§ leads to extensive tissue damage

§ Rapid spreading of infection

Systems of classification

p Bacteria classified into taxonomic groups based:

n size, shape, color, staining properties, respiration and reproduction, immunological, biochemical, or molecular.

p Binomial nomenclature

n Genus

n Specific epithet

p Escherichia coli

Systems of classification

Bacteria: structure

p Prokaryote

n ds circular chromosome (no introns)

n 70S ribosomes

n Cell wall

n Capsules

n Flagella

n Pili

Bacteria: cell wall

Gram stain

Gram Stain Result

Bacteria: Nutrition

p Heterotrophic

n Aerobic (oxygen)

n Anaerobic (inorganic molecule)

n Fermentation (organic molecule)

p Obligate, facultative organisms

Bacteria: Growth and division

p Binary fission

p Depends on:

n nutrients available (E. coli)

n Ability to take in nutrients (Mycobacterium)

p Before cell division:

n DNA replication

n Genome segregation

n Septum formation

Bacteria: Growth and division

Bacteria: Gene expression

p Gene expression

n Transcription

n Translation

p Operons

n Regulation

p Lac operon

Extrachromosomal elements

p Independently replicating nucleic acid molecules

n Plasmids

p Confers advantage to host

§ R factors – antimicrobial resistance

n Bacteriophage – prophage (lysogenic) conversion

p Carry virulence genes - toxins

Mutation and gene transfer

p Leads to changes in bacterial genome

n Mutation – spontaneous or by mutagens

p Repair mechanisms

n Gene transfer and recombination

p Transformation

p Transduction

p Conjugation

p Transposition (transposons)

p Many bacterial genomes have been sequenced

Survival under adverse conditions

p Formation of endospores

n Highly resistant

p Clostridium and Bacillus

n C. tetani à Tetanus

n B. anthracis à Anthrax

Viruses

p Structure

p Infection of host cells

n Receptors for attachment and entry

n Replicates using host machinery

n New virus release by cell lysis or budding

n lysogenic à latent diseases

n Produce cancer cells

Viruses

p Routes of entry

p Transmission

Major groups of viruses

p Tables:

n Type of nucleic acid

n Number of nucleic acid strands and polarity

n Mode of replication

n Size, structure and symmetry

Fungi

p Eukaryote, chitin cell wall

p Unicellular, Filamentous, or fleshy

p Some produce disease

Protozoa

p Single-celled animals

p Free-living or parasites

p Causes disease in humans

n Intracellular and extracelluar pathogens

n acquired through

p contaminated food, water, or insect vectors

p Transmission from mother to fetus (T. gondii)

Helminths

p Parasitic worms

n Flatworms

n Roundworms

n Flukes

p Transmission (fig. 6.1)

p Some disease (Fig. 6.4)

Arthropods

p Insects, ticks, mites

p Feed on human fluid or tissue

p transmission of:

n Viruses (WNV, Dengue)

n Bacteria (plague, lyme disease)

n Protozoa (malaria)

Prions

p Infectious protein

p Causes abnormal changes in brain (spongiform encephalopathy)

p Disease:

n results from ingestion of contaminated meat

n Kuru, scrapie, CJD, new variant CJD, BSE

Host-parasite relationship

p Normal flora

n Acquisition

n Location

n Advantages

n Disadvantages

Host-parasite relationship

p Normal flora

Host-parasite relationship

p Symbiotic association

Host-parasite relationship

p Symbiotic association

Host-parasite relationship