Prokaryotes Flashcards
Differences between prokaryotes and eukaryotes
Circular chromosome (haploid)
70S ribosome (30S+50S)
No organelles
No nuclear membrane
Peptidoglycan
Steps 1-4 of gram staining
1- crystal violet
2- gram iodine
3-decolorizer (alcohol or acetone)
4-safranin red
Gram + bacteria are
Purple
Gram - bacteria are
Pink
Gram + cell walls have
Thick peptidoglycan
Lipoteichoic and teichoic acid
Gram - cell walls have
Thin layer of peptidoglycan
Lipopolysaccharide
Two membranes
Significant periplasmic space
Peptidoglycan is made up of
NAM and NAG joined together by transpeptidase and transglycosylase (penicillin binding proteins, inhibited by beta lactam antibiotics)
Teichoic acid
Gram + bacteria
Cell morphology/division and auto lysis
Regulation of ion homeostasis
Protection from host defenses and antibiotics
Adhesion and colonization
LPS
Gram -
Lipid A (toxic shock, gram - endotoxin)
Polysaccharide core
Repeat units (responsible for O antigen)
Other types of cell walls
Acid fast (Mycobacterium tuberculosis)
Contains mycolic acid and other lipids
Not permeable to normal stains
Use Ziehl-Nielsen stain
AFB=red
Non-AFB=blue
Auramine-rhodamine is
Fluorescent stain used for M. Tuberculosis
Modified acid fast is used to differentiate between
Nocardia vs Actinomyces
Bacteria without cell walls
Mycoplasma (pneumoniae and hominis)
Smallest free living organisms
Flagella
Movement and adherence
Usually not present in gram +
Fimbriae
Attachment to cellular receptors (Proteus miramilis, UPEC, Klebsiella pneumoniae)
Biofilm formation
Gram -/+
Immune evasion
Spores
Resistant to heat and desiccation
Gram + (C. Perfinogens, C. Botulinum, C. Tetanii, C. Difficile, B. Anthracis)
Capsules
Protect against phagocytosis
S. Pneumoniae
Composed of polysaccharide
Biofilms
Antimicrobial resistance
Gene transfer
Mutable
Resistance to immune system
Can be quiescent
First multi-cellular organism
Terminal election acceptor in aerobic vs anaerobic respiration
Oxygen
Other compound such as nitrate
Microaerophiles
Reduced oxygen (campylobacter, helicobacter)
Aerotolerant anaerobes
Not killed by oxygen (streptococci and lactobacilli)
Psychrophiles grow at
Cold temperatures
M leprae grows at
31 degrees C
Eyes, nose, fingers, toes
Sporothrix schenckii grows best at
25 degrees C
Extremities
Rhinovirus grows best at
33 degrees C
Quorum sensing
Cell density regulated gene expression
Cell to cell communication
Hormone like compounds (autoinducers)
Gram += small peptides
Gram -= homoserine lactones
Bacteria replicate though
Binary fission
Bacteria adapt through
Vertical transfer
Horizontal exchange
Acquisition of DNA from other sources
transformation, transduction, conjugation
Examples of transformation
S pneumoniae
Resistance to penicillin and cetraiaxone
DNA uptake apparatus facilitates
Recombination into chromosome by RecA
Transduction-bacteriophage replication cycles can be either _ or _
Lyric or lysogenic
Transduction is
The major mechanism of gene transfer in prokaryotes
Other phage transfer method besides transduction
Pathogenicity islands
Diphtheria-Cornyebacterium diphtheriae uses _ conversion
Lysogenic
Conjugation is the
Transfer of plasmids from one bacterium to another
Transposition is
A type of conjugation
Disease epidemic
Rapid spread within population
Endemic disease
Always present
Pandemic
Epidemic spread to large population (across continents)
Bacterial pathogen strategies
Adherence
Toxin synthesis
Cell invasion
Immune evasion
Metastasis and spread to subsequent colonization
E. coli is a commensalism organism that causes what kinds of diseases?
UPEC- UTI
Sepsis/meningitis- ExPEC, NMEC
Diarrhea
Diarrheagic groups of E. Coli
ETEC-enterotoxigenic
EIEC-enteroinvasive
EPEC-enteropathogenic
EAEC-enteroaggregative
DAEC-diffusely adherent
EHEC-enterohemorrhagic
UPEC
Adheres to uroepithelial cells following colonization of the gut (virulence factors allow for colonization of urinary tract/gut and survival in blood)
S. Aureus is the most common cause of
Endocarditis, nosocomial infection, SSTI, cellulitis, osteomyelitis, septic arthritis
(also common cause of bacteremia, nosocomial pneumonia, foodborne illness, implant infection, abscess)
How does S aureus survive the bloodstream and metastasize
Inhibition of phagocytosis by clotting
SCIN and Ecb bind and inhibit C3b
Interference with RROS production and function
Barrier disruption via alpha toxin binding ADAM 10 receptor
Alpha toxin lysis PMNs

Listeria monocytogenes
Non-pregnant immunosuppressed adults (meningitis, encephalitis, septicemia)
Pregnant women (bacteremia, stillbirth, premature birth)
Listeria monocytogenes virulence factors
Internalin A and B required for host cell invasion
listeriolysin O, phosphatidylcholine-specific phospholipids C=phagosome lysis
Actin assembly-inducing protein- movement in cells
Hexose phosphate- carbon source
Diphtheria exotoxin
Corynebacterium diphtheriae
ADP ribosylating toxin
Inhibits protein synthesis by ribosylating eEF-2
Pertussis exotoxin
Bordetella pertussis
ADP ribosylating toxin binds to G protein
Tetanus toxin
Clostridium tetanii
Causes rigor
Botulism exotoxin
Clostridium botulinum
Causes flaccid paralysis
Superantigen
Some exotoxins bind T cell receptor and MHC II leading to the real ease of chemokines
S aureus TSST-I
Endotoxin
Gram - cell wall LPS
Causes DIC via cytokine storm
Salmonella enterica has _ and _ Serotypes
Typhoid and non-typhoidal (self limiting gastroenteritis)
Salmonella virulence traits
Penetrate intestional epithelium and survive in macrophages
Type III secretion systems (T3SS-1-bacterial internalization and T3SS-2-macrophage survival)
