Intro Lecture Flashcards
What’s the bacterial mass on earth
5 million trillion trillion cells
What’s phylogeny
Science dealing with evolutionary relationships between living organisms. This is based on the sequences of macromolecules such as DNA, RNA, and protein
What is used for phylogenic analysis?
Ribosomes
Bacteria- prokaryotes or eukaryotes. And what differentiates the -karyote type?
Prokaryotes- no nucleus
Do bacteria have membrane bound organelles?
No
What size ribosomes are common in bacteria?
30s&70s
Eukaryotes
40&80
How do bacteria reproduce?
Binary fission
What makes gram positive bacteria distinct?
THICK peptidoglycan.
What makes gram negative bacteria unique from other bacteria?
LPS
What makes mycobacteria unique from other bacteria?
Mycolic acid
What is the primary stain in the gram stain?
Crystal violet
What is the mordant or fixing agent in the gram stain?
Grams iodine
What is used as the decolorizing agent in the gram stain?
Acid Alcohol
What is the counter stain used in the gram stain?
Safranin
What color will gram positive bacteria retain from the gram stain?
Violet
What color will gram negative bacteria retain in the gram stain?
Pink
What two repeating subunits make up peptidoglycan?
N-acetyl glucosamine and n-acetyl muramic acid
What is peptidoglycan responsible for?
80% cell mass
Cell shape
Staining qualities
Osmotic stability
Which portion of LPS is considered the endotoxins
Lipid A portion
What happens in the lag phase of bacterial growth?
Nutrients are acquired and cell growth begins to occur.
What happens in the log phase of bacterial growth?
Rabbits on meth, nutrients are readily available allowing for logarithmic growth and binary fission of bacterial cells.
What is the stationary phase
The phase of cell growth where competition for nutrients and or production of waste products slows growth and reproduction of bacteria
What is the test to determine if Lipid A toxicity exists
LAL
Limulus amebocyte lysate test
Comes from the horse shoe crab
Which cells contain peptidoglycan?
All bacteria
Except mycoplasma and chlamydia
Which bacteria contain Teichoic acid?
Gram +
Acid fast staining of mycobacteria is accomplished by?
Mycolic acid
For flagella
1 flagella
Monotrichous
Flagella
2 flagella one at each pole
Amphtrichous
Flagella, flagella every where all over the cell!
Peritrichous
Flagella lots of em all on one pole of the bacteria
Lophotrichous
Where would you find endoflagella or axial filaments?
Spirochetes
What are pili/fimbriae?
Small thread like structures used to adhere to host tissue- NOT FLAGELLA!
They contribute to antigenicity
Eg bordatella, e. Coli
What fimbrial antigens of E. coli are in neonatal pigs?
K88
What fimbrial antigens of E. coli are in neonatal calves?
K99
What is a capsule
Polysaccharide outer coating of the bacteria that helps the organism evade phagocytosis
Ex bacillus anthracis
What are endospores
Endospores are produced when nutrients are depleted in a bacteria. Dipocolinic acid then coats the spore to protect it from the environment.
Eg clostridium and bacillus
Bacterial that require oxygen for growth
Aerobic, microaerophilic, capnophilic
Oxygen not required or utilized for growth
Obligate anaerobic, aero tolerant anaerobic
Oxygen not required but can be utilized for growth
Facultative anaerobes
What’s the definition of bacterial virulence factors
Properties or traits found in isolates that cause disease but which are not found in isolates of the same species that lack the ability to cause disease
What are some ways damage can be caused due to bacteria?
Using the hosts nutrients
Direct damage to the host cell (toxins)
Hypersensitivity reactions
(Type 4- TB)
What is pathogenicity?
The ability of a pathogen to produce a disease by overcoming the defense mechanisms of the host
_____ is the degree of pathogenicity
Virulence
What type of macromolecules are exotoxins?
Proteins
Where and why are exotoxins produced?
Inside mainly gram positive bacteria as a part of their growth and metabolism.
How do exotoxins leave the bacteria?
Either by secretion or released following cell lysis
Which type of bacterial cell has endotoxins and where are they located?
Gram negative species, cell wall
Where are endotoxins produced
Endotoxins are produced in the Lipid A portion of lipopolysaccharide of Gram Negative bacteria
How do Endotoxins leave the bacteria?
Endotoxins are liberated when gram negative bacteria die and the cell wall degrades, thus releasing the endotoxin
______ this chemical kills white blood cells (phagocytes).
Leukocidins
_______ destroy erythrocytes
Hemolysins
Most exotoxins are what type of toxins?
A-B Toxins, Where the A peptide is the active enzyme (does the damage) and the B peptide is the peptide that binds.
What type of activation of T-cells do Superantigens cause
non specific
What is the result of Superantigen binding?
Polyclonal T cell activation and massive cytokine release. Toxic Shock Syndrome- Staph and Strep
Who all produces Superantigens?
pathenogenic microbes (viruses, mycoplasma, and some bacteria)
What is the binding of Superantigens
indiscriminate binding to MHC class 2 on the APC and T helper cell receptor.
What are clinical signs of superantigens?
Nausea, vomiting, Fever, shock
what are plasmids?
smaller circular DNA present in Bacteria
What are bacteriophages?
Virus particles that attack bacteria.
______ is the process by which one bacterium ( with fertility factor) transfers genetic material to another through direct contact.
Conjugation
_____ is the genetic alteration of a cell resulting from the direct uptake and incorporation of exogenous genetic material from its surroundings and taken up through the cell membrane.
Transformation
______ is the process by which DNA is transferred from one bacterium to another by a virus.
Transduction
_____ conversion with bacteriophages can result in bacteria with virulence factors, such as toxins or capsules.
Lysogenic
what is biofilm?
Microbes come together in masses cling to surfaces, produce extracellular substances and take in nutrients and form a biofilm.
What is Quorum Sensing?
Once bacteria reach certain numbers they change their behavior, appearance, and metabolism. These changes culminate in an infection that can ambush and overwhelm the immune system.
What is an opportunistic pathogen?
organisms that do not cause disease in a healthy host, with a healthy immune system.
What are true pathogens?
Pathogens equipped with virulence genes for adherence, invasion, and evasion from the immune system and toxins.
What are infections acquired from hospitals?
nosocomial ex MRSA
In general where are most bacterial infections?
extracellular
What are some intracellular bacteria?
Rickettsia, Chlamydia
Which bacteria is Facultative intracellular bacteria?
Mycobacterium
