exam 1 micro lecture

6 (7) types of microbes

bacteria, viruses, fungi, protozoa, helminths, algae and prions (newly)

existed for 3.5 billion yrs

at a micrometer or nanometer scale

immunology

study of immune system

public health micro bio and epidemiology

monitoring and control of diseases spreading

biotechnology

production of food, drugs and vaccines thru organisms

prokayrotes

prenucleus (no nucleus), simple cell, no dna, unicellular. one circular chromosome,

not in a membrane, No histones, No organelles, Peptidoglycan cell walls if Bacteria, Binary fission

eukaryotes

true nucleus, larger, complex cells, dna and multicellular. Paired chromosomes,

in nuclear membrane, Histones, Organelles, Polysaccharide cell walls, Mitosis.

viruses

neither prokaryote or eukaryote. they’re their own classification. no cells (acellular), parasitic particles composed of nucleic acid and protein.

most abundant microbe on earth

obligate intracellular parasite

bear no resemblance to cells: Lack protein-synthesizing machinery, contain only the parts needed to invade and control a host cell

Structure of Viruses

capsids- protein coats made of capsomeres

nucleocapsid- capsid together with the nucleic acid

envelope or naked

can be helical or icosahedral (20 sides)

photosynthesis

light from sun, turns to sugar. fuled by light co2, turns to organic material

decomposition

energy released in heat and broken down

bio remediation

using living organisms to remedy environment problems (ex. cleaning oil spills)

genetic engineering

manipulating genes to make new products

pasteurization

application of high heat for short time

bacilllus thuringienis

toxic crystals causing pests to have fatal infections (pesticides not harmful to humans)

normal microbiota

microbe thats normally pressent in/on humans. (not always harmful!!!) also prevents pathogen growth and produces growth factors (ex. potassium)

pathogens

ALWAYS HARMFUL microbes. 10B new infections and 12M deaths annually ☹

robert hooke

discovered cells for the first time

antonie Van Leeunwenhoek

first to obserVe Living microbes (using single lens 300x)

theory of spontaneous generation

life forms can arise from vital forces present in nonliving/decomposing matter

theory of biogenesis

came from louis pasteur, the idea that living things only come from other living things

louis pasteur

demonstrated that microorganisms are in the air

pasteurization (heated and sealed = no growth)

s shaped flask, kept microbes out but let air in

started “golden age” of micro bio

yeast causes fermentation

theory of biogenesis

rabies caused by a virus

fermentation

when sugar turns to alcohol. microbial growth causes food to spoil, bacteria that use alcohol and produce acetic acid spoil wine and turn to vinegar

joseph lister

founder of anti septic medicine, used chemical disinfectant to prevent surgical infections

robert koch

proved that a bacterium causes anthrax

identified cholera and koch’s postulates (criteria that proves a certain microorganisms cause a specific disease)

edward jenner

discovered a person w cow pox can’t get small pox

vaccination/immunity- vacca = cow

chemotherapy

treatment with chemicals

synthetic drugs used to treat disease

antibiotics

chemicals produced by bacteria/fungi that’ll kill other microbes

paul ehrlich

discovered magic bullet that can kill pathogen without hurting host

developed arsenic, salvarsan, to treat syphillis

Alexander fleming

discovered first Antibiotic, penicillium

made penicillin (kills S. aureus)

different branches of microbio

bacteriology-study of bacteria

mycology-study of fungi

virology- study of viruses

parisitology- study of protozoa and parasitic worms

George beadle and Edward tatum

showed Genes encode a cell’s Enzymes

Oswald Avery, Colin MacLeod and Maclyn McCarty

showed DNA was hereditary material

francois jacob and jacques monod

discovered role of mRNA in protein synthesis

Bruce A Beutler and Jules A Hoffmann

discovered innate immunity and molecules

ralph steinman

discovered adaptive immunity and dendritic cells

rebecca lancefield

proposed use of immunology to identify some bacteria according to serotypes

Nobel Prizes for Microbiology Research

john tyndall and ferdinand cohn

discovered present of heat resistant forms

cohn determined these forms as endospores

taxonomy

organizing, classifying, and naming living things

classification (grouping), nomenclature (naming) and identification (identifying traits for placement)

levels of classification

Domain - Archaea, Bacteria, & Eukarya

Kingdom

Phylum or Division

Class

Order

Family

Genus

Species

(dear king phillip came over for good soup)

3 domains of life

bacteria (true bacteria), archaea (odd bacteria that lives in extreme environments) and eukarya (organisms w nucleus and organelles)

binomial nomenclature

genus is capitalized and species is lowercase (ex. Staphylococcus aureus, S. aureus, Staphylococcus sp.)

specific epithet

another word for species

phylogeny

natural relatedness between groups of organisms

*know the basic idea of evolution*

shapes of bacteria

Bacillus (rod-shaped), Coccus (spherical), Spiral: Spirillum, Vibrio, Spirochete

unusual bacteria shape includes star shape and rectangular shape bacteria

arrangements

Pairs: Diplococci, diplobacilli

Clusters: Staphylococci

Chains: Streptococci, Streptobacilli

The Structure of a Prokaryotic Cell: Glycocalyx

Outside cell wall is Usually sticky

Capsule: neatlyorganized

Slime layer: unorganized and loose

Extracellular polysaccharide allows cell to attach

Capsules prevent phagocytosis

The Structure of a Prokaryotic Cell: Flagella

Outside cell wall Made of chains of flagellin

Attached to a protein hook

Anchored to the wall and membrane by the basal body

Motile Cells

Rotate flagella to run or tumble

Move toward or away from stimuli (taxis – photo, chemo)

Flagella proteins are H antigens

Axial Filaments

Also called endoflagella

In spirochetes

Anchored at one end of a cell

Rotation causes cell to move

Fimbriae and Pili

Fimbriae: allow attachment

Pili: Facilitate transfer of DNA from one cell to another, Gliding motility, Twitching motility

The Cell Wall

Prevents osmotic lysis (rupturing of a cell membrane caused by excess water/osmosis)

Made of peptidoglycan (in bacteria)

Peptidoglycan

Polymer of disaccharide (NAG and NAM)

Peptidoglycan in Gram-Positive Bacteria linked by polypeptides

gram positive vs gram negative bacterial wall

g+ = Thick peptidoglycan and Teichoic acids. Lipoteichoic acid links to plasma membrane. Wall teichoic acid links to peptidoglycan. polysaccharides provide antigenic variation. killed by penicillin and detergents. 2 ring basal body

g- = Thin peptidoglycan, Outer membrane, Periplasmic space. resistant to antibiotics 4 ring basal body, endotoxin

→ outer membrane: Lipopolysaccharides, lipoproteins, phospholipids. Forms the periplasm between the outer membrane and the plasma membrane. Protection from phagocytes, complement, and antibiotics. O polysaccharide antigen, Lipid A is an endotoxin, Porins (proteins) form channels through membrane

staining slides (for contrast)

Smear: A thin film of a solution of microbes on a slide. usually fixed to attach the microbes to the slide and to kill the microbes

Stains consist of a positive and negative ion

→ basic dye: the chromophore is a cation. used once in simple stain

→ acidic dye: the chromophore is an anion

negative staining: staining background instead

mordant: used to hold the stain or coat the specimen to enlarge it

Differential Stains: Used to distinguish between bacteria. Gram stain and Acid-fast stain

gram stain

classifies bacteria into gram positive or gram negative. all gram pos are purple. gram neg decolorizing is clear, gram neg counter stain is red

gram pos: alcohol dehydrates peptidoglycan

gram neg: alcohol dissolves outer membrane and leaves holes in peptidoglycan

atypical cell walls

acid fast cell walls, like gram pos.

waxy lipid/mycolic acid bound to peptidoglycan

mycobacterium and nocardia

mycoplasmas lack cell walls. sterols in plasma membrane

archaea are wall-less or waks of pseudomurein (lack NAM and D-amino acids)

acid fast stain

stain waxy cell wall not decolorized by acid alcohol. mycobacterium and nocardia

acid fast= all red

non acid fast recolorizing is colorless, non acid fast counter stain is blue

special stains

used to distinguish part of cells:

capsule stain- cells stained, negative stain

endospore stain- primary stain is malachite green with heat. decolorizes cells (water) and counterstain is safranin

flagella stain- mordant on flagella, carbolfuchsin simple stain

damage to cell wall

lysozome digests disaccharide in peptidoglycan

penicillin inhibits peptide bridges in peptidoglycan

protoplast- spherical shape assumed by gram pos bacteria

spheroplast- spherical shaoe assumed by gram neg bacteria.

both are susceptible to osmotic lysis

L forms- wall’less cells that swing into irregular shapes

plasma membrane

has phospholipid bilayer, peripheral proteins, integral proteins and transmembrane proteins.

selective permeability allows passage of some molecules

damage to membrane by alcohol detergents etc causes leakage of cell contents

fluid mosaic model

similar consistency to olive oil

proteins move to function

phospholipids rotate and move laterally (sideways)

movement of materials across membranes

thru lipid layer and aquaporins (water channel)

active transport requires ATP and transporter protein

group translocation requires transporter protein and PEP

simple diffusion- solute moving from area of high concentration to low concentration

facilitated diffusion- solute combines with a transporter protein in membrane

osmosis- movement of water across selectively permeable membrane from area of high water concentration to area of low water concentration

→ isotonic is no movement of water. hypertonic causes shrinkage. hypotonic causes swelling or bursting

prokaryotic ribosome

protein synthesis

30s (small subunit) + 50s (large subunit) = 70s complete ribosome

inclusions

phosphate reserves: metachromatic granules (volutin)

energy reserves: polysacchardie granules, lipid inclusions and sulfer granules

endospores

resting cells resistant to desiccation, heat chemicals. ex: bacillus or clostrdium

sporulation: endospore formation

germination: return to vegitative state

history of eukaryotes

2 bill yr

evolution from prokaryotic by symbiosis

kingdom fungi

macroscopic fungi (mushroom)

microscopic (yeast): 2 morphologies. yeast ( round and asexual) and hyphae (long fungi) can be dimorphic

unicellular or colonial mostly

fungal nutrition

heterotrophic

most are harmless, some are parasites

mycoses- fungal infection

fungal organization

yeast- soft, uniform and reproduce by budding

filamentous fungi- mass of hyphae called mycelium, can be cottony/hairy. hyphae might be dividied by septate. reproductive hyphae = spores

protists

algae- eukaryotic, microscopic are unicellular, macroscopic are multicellular. all are colonial. photosynthesize w chlorophylla. cell wall, may or may not have flagella. plankton, dinoflagellaten (can cause red tides and food poisoning)

protozoa- eukaryotes that are mostly unicellular, lack tissue and cell wall. many shapes. most are harmless. feed by engulfing other things. all heterotrophs, none have chloroplasts. cytoplasm is divided into endoplasm and ectoplasm

protozoan pathogens

Pathogenic flagellates: ex Trypanosomes -T. brucei – African sleeping sickness and T. cruzi – Chaga’s disease; South America

infective amoebas: ex Entamoeba histolytica- amebic dysentery

parasitic helminths

flatworms like Cestodes (tapeworms) or Trematodes. simple excratory and nervous system

Roundworms (nematodes) – round, a complete digestive tract, a protective surface cuticle, spines and hooks on mouth; excretory and nervous systems poorly developed

nucleic acid

Viral genome – either DNA or RNA but never both

Carries genes necessary to invade host cell and redirect cell’s activity to make new viruses

Number of genes varies for each type of virus

DNA viruses Usually double stranded (ds) but may be single stranded

(ss Circular or linear

RNA viruses Usually single stranded, may be double stranded

modes of multiplication

1. Adsorption – binding of virus to specific molecules on the host cell

2. Penetration – genome enters the host cell

3. Uncoating – the viral nucleic acid is released from the capsid

4. Synthesis – viral components are produced

5. Assembly – new viral particles are constructed

6. Release – assembled viruses are released by budding (exocytosis) or cell lysis

Cytopathic effects

virus-induced damage to cells

1. Cells fuse to form multinucleated cells

2. Cell lysis

3. Alter DNA

4. Transform cells into cancerous cells

Techniques in Cultivating and Identifying Animal Viruses

Cell (tissue) cultures, Bird embryos and Live animal inoculation

prions

misfolded proteins, contain no nucleic acid. extremely resistant to usual sterilization techniques, can be fatal

Scrapie in sheep and goats

Bovine spongiform encephalopathies (BSE), a.k.a. mad cow disease

Wasting disease in elk

Humans – Creutzfeldt-Jakob Syndrome (CJS)