exam 2 dr dolan microbiology

Bordetella pertussis

***aerobic, fastidious, use special techniques to identify

whooping cough, pertussis

Candida albicans

fungal infection due to any species of the genus Candida (*****YEAST). thermally dimorphic, escomicota

member of mucosal microbiota

ORAL THRUSH, VAG YEAST INFECTIONS, UTI, DENTERSTONITIS, major cause of death in cancer patients

Ehrlichia chaffeensis

is an obligate ****intracellular, Gram-negative species of Rickettsiales bacteria, INSECT VECTOR DISEASE

Haemophilus influenzae

Gram-negative, non-motile, coccobacillary, facultatively anaerobic, capnophilicpathogenic bacterium of the family Pasteurellaceae. The bacteria are mesophilic and grow best at temperatures between 35 and 37 °C

****REQUIRES ELEVATED LEVELS OF CO2

UPPER RESPIRATOTY INFECTIONS, EAR INFECTIONS including pneumonia, meningitis, or bloodstream infections.

Moraxella catarrhalis

fastidious, nonmotile, ***Gram-negative****, aerobic, ***oxidase-positive ***diplococcus*** that can cause infections of the respiratory system, middle ear, eye, central nervous system, and joints of humans.

This bacterium has been known to cause otitis media, bronchitis, sinusitis, and laryngitis.

Streptococcus pyogenes

***Gram-positive, aerotolerant beta hemolytic

ranging from mild superficial skin infections to life-threatening systemic diseases. The most frequent manifestations of disease are commonly known as scarlet fever. Infections typically begin in the throat or skin. The most striking sign is a strawberry-like rash. Examples of mild S. pyogenes infections include pharyngitis (strep throat) and localized skin infection (impetigo).

Louis Pasteur

postulated that rabies was caused by a virus

Ivanovski and Beijerinck

showed a disease in tobacco was caused by a virus

Viruses

-noncellular particles with a definite size, shape, and chemical composition

-obligate intracellularparasites

-Most

All viruses contain

capsid, nucleic acid.

capsid

protein shell that protects the nucleic acid

nucleic acid

either rna or dna never both

many viruses contain

envelope- piece of host cell membrane wrapped around the capsid

and spike fibers - proteins that help attach to host cell

those lacking an envelope are

naked

Helical

Continuous helix of capsomers

Forms cylindrical nucleocapsid

Icosahedral

20-sided with 12 corners

Viral envelope

mostly animal viruses

Exposed proteins on the outside of the envelope, called spikes, areessential for attachment of the virus to the host cell

Complex viruses: atypical viruses

Poxviruses lack a typical capsid and are covered by a dense layer oflipoproteins

Some bacteriophages have a polyhedral nucleocapsid along with ahelical tail and attachment fibers

Viral genome

either DNA or RNA but never both

Carries genes necessary to invade host cell and redirect cell'sactivity to make new viruses

DNA viruses

Usually double stranded (ds) but may be single stranded (ss)

Circular or linear

RNA viruses

Usually single stranded, may be double stranded, may be segmentedinto separate RNA pieces

ssRNA genomes ready for immediate translation are positive-senseRNA

ssRNA genomes that must be converted into proper form are negative-sense RNA

Information flows in one direction and one direction only

DNA -> RNA -> Protein -> Trait

Animal Virus Replication

1. Adsorption

2. Penetration

3. Uncoating

4. Synthesis

5. Assembly

6. Release

Adsorption

the virus attaches to its host cell by specific binding of its spikes to cell receptors

penetration

The virus is engulfed by the cell membrane into a vesicle or endosome and transported internally.

Endocytosis - entire virus is engulfed and enclosed in a vacuole orvesicle

Fusion - envelope merges directly with membrane resulting innucleocapsid's entry into cytoplasm

uncoating

Conditions within the endosome cause fusion of the vesicle membrane with the viral envelope, followed by release of the viral capsid and RNA into the cytoplasm.

Synthesis

under the control of viral genes, the cell syntheses the basic components of new viruses. rna molecules, capsomers, and spikes

assembly

Viral spike proteins are inserted into the cell membrane for the viral envelope; nucleocapsid is formed from RNA and capsomers

release

Enveloped viruses bud off of the membrane, carrying away an envelope with the spikes. This complete virus or virion is ready to infect another cell.

2 ways:

Budding - exocytosis; nucleocapsid binds to membrane which pinchesoff and sheds the viruses gradually; cell is not immediately destroyed

Lysis - nonenveloped and complex viruses released when cell diesand ruptures

comparison of bacteriophage and animal virus

bacteriophage vs animal

1. precise attachment of special tail fibers to cell wall VS Attachment of capsid or envelope tocell surface receptors

2. injection of nucleic acid through cell wall NO uncoating of nucleic acid VS Whole virus is engulfed and uncoated,or virus surface fuses with cellmembrane; nucleic acid is released

3. Occurs in cytoplasm (no nucleus present)Cessation of host synthesisViral DNA or RNA replicatedViral components synthesized VS Occurs in cytoplasm and nucleus

4. Lysogeny VS Latency, chronic infection, cancer

5. Cell lyses afterbeing weakened by viral enzymes VS Some cells lyse; enveloped virusesbud off host cell membrane

6. very sudden VS Sudden (lysis) or slow (budding)

Bacteriophages

bacterial viruses (phages)

Steps in Phage Replication

1. Adsorption - binding of virus to specific molecules on hostcell

2. Penetration - genome enters host cell

3. Replication - viral components are produced

4. Assembly - viral components are assembled

5. Maturation - completion of viral formation

6. Lysis & Release - viruses leave the cell to infect other cells

Cultivating and Identifying Animal Viruses

Obligate intracellular parasites

Require appropriate cells to replicate

Methods used: Cell (tissue) cultures - cultured cells grow in sheets that support viral replication and permit observation for cytopathic effects

Bird embryos - incubating egg is an ideal system; virus is injectedthrough the shell

Live animal inoculation - occasionally used when necessary

Prions

misfolded proteins, contain no nucleic acid•

Extremely resistant to usual sterilization techniques• Cause transmissible spongiform encephalopthies - fatal neurodegenerative diseases

prions diseases

Common in animals

Scrapie in sheep and goats

Bovine spongiform encephalopathies (BSE), a.k.a. mad cowdisease

Wasting disease in elk

Humans - Creutzfeldt-Jakob Syndrome (CJS)

A mesophile

an organism that grows best at moderate temperatures

20c-45c also the temp of warm blooded animals

Nutrition

Process by which chemical substances (nutrients) are acquired from the environment and used in cellular activities

Essential nutrients

Must be provided to an organism

Macronutrients

Required in large quantities

Play principal roles in cell structure and metabolism• CHONPS

Micronutrients or trace elements

Required in small amounts

Involved in enzyme function and maintenance of protein structure

Manganese, zinc, nickel

Organic nutrients

Contain carbon and hydrogen atoms

Usually produced by living things

Methane (CH4), carbohydrates, lipids, proteins, and nucleic acids

Inorganic nutrients

Atom or molecule that contains a combination of atoms other than carbon and hydrogen

Metals and their salts (magnesium sulfate, ferric nitrate, sodiumphosphate), gases (oxygen, carbon dioxide) and water

Heterotroph

Must obtain carbon in an organic form made by other living organismssuch as proteins, carbohydrates, lipids, and nucleic acids

Autotroph

Organism that uses CO2, an inorganic gas as its carbon source

Not nutritionally dependent on other living things

Chemotroph

Gain energy from chemical compounds

Phototrophs

Gain energy through photosynthesis

Photoautotrophs

Makes free oxygen during photosynthesis

Chemoautotrophs

survive totally on inorganic substances

Use inorganic forms of carbon

Saprobes

Feed on organic detritus from dead organisms• Opportunistic pathogen• Facultative parasite

Parasites

Derive nutrients from living host

Pathogens

Some are obligate parasites

Metabolism

all chemical and physical workings of a cell

Catabolism

degradative; breaks the bonds of larger moleculesforming smaller molecules; releases energy

Anabolism

biosynthesis; process that forms larger macromoleculesfrom smaller molecules; requires energy input

Enzymes

biological catalysts• Increase the rate of a chemical reaction by lowering the energy ofactivation (the resistance to a reaction)

aerobic respiration

Series of enzyme-catalyzed reactions in which electronsare transferred from fuel molecules (glucose) to oxygen asa final electron acceptor

glycolysis

Glucose (6C) is oxidized and split into 2 molecules of pyruvate (3C)• NADH is generated

^Starts by burning ATP to energize the process• Phosphorylated glucose splits in two• Each half goes thru the same set of subsequent reactions

(apart of aerobic respiration)

Kreb's Cycle

Processes pyruvic acid and generates 3 CO2 molecules• NADH and FADH2 are generated

(apart of aerobic respiration)

Electron transport chain

Accepts electrons from NADH and FADH• Generates energy through sequential redox reactions calledoxidative phosphorylation

(apart of aerobic respiration)

Glycolysis: Inputs and Outputs

inputs: Glucose. ATP (2) NAD. ADP

outputs: Pyruvate ADP NADH+H+ ATP (4)

atp yield: Burn 2 Make 4 Net Yield: +2ATP

fate of pyruvate

transition step

In eukaryotic cell, corresponds to movement from cytoplasm tomitochondrion

Coenzyme A is a carrier of two-carbon acetyl groups

Like electrons and protons, acetyl groups get an escort through the cell

inputs- Pyruvate CoA NAD

outputs- Acetyl-CoACO2NADH+H+

Krebs cycle

inputs: Acetyl CoA NAD FAD ADP

outputs: CO2 + CoA NADH+H+ FADH2 ATP

Electron Transport & Oxidative Phosphorylation

Final processing of electrons and hydrogen and the majorgenerator of ATP

Chain of redox carriers that receive electrons from reduced carriers (NADH and FADH2)

ETS shuttles electrons down the chain, energy is released and subsequently captured and used by ATP synthase complexes to produce ATP via Oxidative phosphorylation

Chemiosmosis

As the electron transport carriers shuttle electrons, they actively pumphydrogen ions (protons) across the membrane

Proton motive force

The resulting gradient of hydrogen ions

Hydrogen ions diffuse back through the ATP synthase complex

Causing the production of ATP

The Terminal Step of Aerobic Respiration

Oxygen accepts 2 electrons from the ETS and then picks up 2 hydrogen ions from the solution to form a molecule of water.

Oxygen is the final electron acceptor2H+ + 2e- + ½O2 → H2O

Electron Transport Chain

Recycle NADH and FADH2 back to NAD and FAD to start the process again

Dump used electrons onto the final electron acceptor• Generate large numbers of ATP molecules

INPUTS- NADH+H+FADH2 ADP O2

OUTPUTS- NAD FAD ATP H2O

Theoretic ATP Yield for Aerobic Respiration

AEROBIC

ANAEROBIC

FERMENTATION

Photosynthesis: The Earth's Lifeline

Ultimate source of all chemical energy in cells comes from the sun

Photosynthesis convert light energy into chemical energy in foods.

6CO2 + 6H2O-----> C6H12O6 + 6O2. (Glycolysis->Glucose)

Photosynthesis: Stage 1

Light-dependent Reactions:

Photons are absorbed by chlorophyll,carotenoid, and phycobilin pigments

Water split by photolysis

Releases O2 gas

Provides electrons to drive photophosphorylation

Released light energy used to synthesize ATP and NADPH

(INPUT) Sunlight H2O NADP ADP

(OUTPUT) O2 NADPH+H+ ATP

Photosynthesis: Stage 2

Light-independent reaction

Also known as dark reactions and the Calvin cycle

Uses ATP to fix CO2 to ribulose-1,5-bisphosphate

Ultimately gets converted to glucose

(INPUT)CO2 NADPH+H+ ATP

(OUTPUT) Glucose NADP ADP