Bacterial Structure 1 & Bacteria virulence factors Flashcards
Bacteria are present where? (term: ?)
Essential for the existence of ? on Earth
- Ubiquitous and numerous
- are bacteria more beneficial or more pathogenic?
- size ?
**Morphologies - few or diverse?
sphere-shaped - bacteria name?
rod-shaped - bacteria name?
name some other shapes?
Bacteria are EVERYWHERE (omnipresence)
Essential for the existence of all life on Earth
- Ubiquitous and numerous
- are bacteria more beneficial or more pathogenic? - more are beneficial relative to pathogenic
- size ? = very small (invisbile to the naked eye)
sphere shaped - cocci
-> coccus, diplococci, diplococci (encapsulated), staphylococci, streptococci, sarcina coccus, tetrad coccus
rod-shaped - bacilli
-> coccobacillus, bacillus, diplobacilli, streptobacilli, palisades
other shapes
- club rod, vibrio, spirillum, helical form, spirochete, filamentous
red ball thing in Clostridium tetani is bacterial spores
majority of arrangement of bacteria is?
majority of arrangement of bacteria is diplococci
SIZES
bacteria’s normal range is between #micrometer? to #? micrometer and can be seen through which type of microscope?
In general, bacterial sizes (diameter) range from 1 μm to 5 μm (true range: ? μm – ? cm)
virus, mycoplasma, bacteria, yeasts, eukaryotic cells and mycelia -> arrange smallest to largest
naked eye can see which range of micrometer
light microscopy can see which range of micrometer
electron microscopy can see which range of micrometer
bacteria’s normal range 1 micrometer to 5 micrometer and can be seen through both light and electron microscopy
In general, bacterial sizes (diameter) range from 1 μm to 5 μm (true range: 0.1 μm – 2.0 cm)
VMBYEM
virus, mycoplasma, bacteria, yeasts, eukaryotic cells and mycelia
naked eye can see 100 micrometer to 500 micrometer
light microscopy can see 0.3 micrometer to 500 micrometer
electron microscopy can see from 0.05 micrometer to 50 micrometer
Cell structure
- Prokaryotes (pro – means?; karyote – means?)
- Unicellular or multicellular organisms?
- Lack of ? organelles and ? nucleus
All bacteria have: list 5
Some bacteria have: list 4
Some bacteria can produce: ?
Cell structure
- Prokaryotes (pro – before; karyote – nucleus)
- Unicellular organisms
- Lack of membranous organelles and true nucleus
All bacteria have:
cell membrane
ribosomes
cytoplasm
complex and rigid cell wall (except mycoplasma - no cell wall)
nucleoid (DNA)
Some bacteria have:
capsule
flagella
pili/fimbriae
plasmids
Some bacteria can produce: endospores
CYTOPLASM: is ? aqueous solution (cytosol)
Functions:?
Contains: ?
label image: what is white thing and black dots
NUCLEOID (DNA)
* The bacterial ?
* single or double-stranded DNA?
* mostly or some? single* (haploid) and circular*
is the circular or straight shape better for protection?
Function
* Contains the ? for the life of the bacteria (core-genome)
Cytoplasm: is jelly like aqueous solution (cytosol)
Functions: facilitate major chemical rxns of the cell
Contains: nuceloid (DNA) and ribosomes
label image: white thing is the DNA so 2 chromosomes and black dots are ribosomes
NUCLEOID (DNA)
* The bacterial chromosome
* double-stranded DNA?
* IMP -> mostly single* (haploid) and circular*
is the circular or straight shape better for protection? - circular (other shape more prone to attack by toxins)
Function
* Contains the essential genes for the life of the bacteria (core-genome)
PLASMIDS:
- DNA molecule -> which shape?
- single or Double-stranded DNA?
- Some are ? (able to be passed to other bacteria)
- Contains additional genes, not ?
Functions:
* Provide ? factors (genes)
* ? resistance (genes)
* & other genes…
Ribosomes:
* The cellular ? factory
* Composed by ? & ?
* Two subunits = large (?) and small (?)
* ? genetic code
* Applications = therapy + phylogeny
for therapy bc stop the production of proteins then u die so good target for therapy and
2. if its conserved then we can build bullet (not a specific one tho)
phylogen: if we read how its composed then we can organize that we can understanding of microbes
PLASMIDS:
- DNA molecule -> circular
- Double-stranded DNA?
- Some are conjugative (able to be passed to other bacteria)
- Contains additional genes, not essential
Functions:
* Provide virulence factors (genes)
* antibiotic resistance (genes)
* & other genes…
Ribosomes:
* The cellular protein factory
* Composed by proteins & rRNA
* Two subunits = large (50s) and small (30s)
* conserved genetic code
* Applications = therapy + phylogeny
for therapy bc stop the production of proteins then u die so good target for therapy and
2. if its conserved then we can build bullet (not a specific one tho)
phylogen: if we read how its composed then we can organize that we can understanding of microbes
Bacterial envelope:
1. plasma membrane is aka what membrane?
2. ? proteins
3. do they have a cell wall and what is in it?
4. Allows the ? of the two main groups of bacteria which are ?
Bacterial envelope:
1. cytoplasmic or plasma membrane
2. membrane-associated proteins
3. cell wall (peptidoglycan layer)
4. Allows the characterization of the two main groups of bacteria which are gram + and - (- always have 2 cytoplasmic membranes)
Bacterial envelope:
- Plasma membranes or ? have:
list 4 characteristics - Membrane-associated proteins:
list 4 characteristics - Cell wall (peptidoglycan layer)
Peptidoglycan = chain of alternating subunits of ?
Functions
- Protection against ? and ?
- ? transport
- differences in ? and ? - pathogenicity and ? properties - Allows the characterization of the two main groups of bacteria
Gram staining technique:
step 1: “ ? “
primary stain added to specimen
step 2: “ ? “
mordant makes dye more or less? soluble so it adheres to cell walls
step 3: ?
decolorizer washes away stain from gram (-) cell walls
step 4: ?
counterstain allows dye adherence to ? cell walls.
stays purple due to the presence of a ? layer of peptidoglycan in whose cell walls? which retains the crystal violet these cells are stained with
- Cytoplasmic membrane
■ Flexible structures
■ Layercomposedofphospholipidsandproteins
■ No sterols (presentineukaryoticcells)
■Outer faces are hydrophilic, interior hydrophobic - Membrane-associated proteins:
■ Stabilization of membrane
■ Transportof molecules
■ Electron transport for bacterial respiration
■ Enzymes - Cell wall (peptidoglycan layer)
Peptidogly”can” (reverse: NAC -> NAG NAM nag nam nag nam…) = chain of alternating subunits of N- acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) crosslinked with short peptides
Functions
- Protection against mechanical damage and osmotic lysis
- non-selective transport
- differences in structure and chemical composition - pathogenicity and staining properties
- Allows the characterization of the two main groups of bacteria
Gram staining technique:
step 1: “crystal violet”
primary stain added to speciment
step 2: “iodine”
mordant makes dye less soluble so it adheres to cell walls
step 3: Alcohol
decolorizer washes away stain from gram (-) cell walls
step 4: safranin (pink in color)
counterstain allows dye adherence to gram (-) cell walls.
stays purple due to the presence of a thick layer of peptidoglycan in the gram + cell walls, which retains the crystal violet these cells are stained with
Bacterial envelope:
Outer membrane
* Only in Gram-? bacteria
(things happen in which space? where what is present?)
Contains:
* Lipopolysaccharide: ?
Porins: ?
Transporter proteins: ?
Alternative structural bacterial envelopes:
Mycobacteria
* Bacterial envelope contains ** ? **
* ? cell wall
* ? staining for identification
Mollicutes (Mycoplasma)
* ** ? ~ no ? layer **
* Highly ? and ? unstable
* The ? bacteria described
(- need which microscope to see them)
Bacterial envelope:
Outer membrane
* Only in Gram-negative bacteria
(things happen in periplasmic space where peptidoglycan is present)
Contains:
* Lipopolysaccharide: a strong immunologic molecule called endotoxin
Porins: protein channels that allow small hydrophilic molecules
Transporter proteins: enable transport of large nutrients
Alternative structural bacterial envelopes:
Mycobacteria (note myco - bacteria; myco - lic acids)
* Bacterial envelope contains ** mycolic acids **
* thick waxy hydrophobic cell wall
* acid-fast staining for identification
Mollicutes (Mycoplasma)
* IMP!!! ** no cell wall ~ no peptidoglycan layer ** (all other bacteria have cell wall)
* Highly pleomorphic and osmotically unstable
* The smallest bacteria described
- need electron microscope to see them
Capsule:
- ?, an extracellular polymeric matrix
- in ? bacterial species
Functions: list 3
what is green thing in pic?
FLAGELLA:
* Anchored to the ?
* ?-protein structure (engine)
* The ? and ? vary between
bacteria
- Functions:
?
Capsule:
- glycocalyx, an extracellular polymeric matrix
- in some bacterial species
Functions:
1. protection (environment, phagocytosis)
2. cell adherence
3. nutrient reserve
what is green thing in pic? -> glycocalyx
FLAGELLA:
* Anchored to the bacterial cell envelope
* multi-protein structure (engine)
* The number and position vary between
bacteria
- Functions:
locomotion or bacterial motility
Pili/fimbriae:
* ? appendages attached to ?
* Known as “?”
* Most common on which type of bacteria?
Function
* Adhesion to ? (specificity)
* Contribute to ?
Endospores:
* Cryptobiotic state of ? and most ? type of cell found in nature
* Produced by some ? bacteria
* Examples of pathogenic genera: ? and ?
Function
* Ensure survival during ? environmental conditions
* ? bodies
Pili/fimbriae:
* fine straight hair like appendages attached to cell wall
* Known as “adhesins”
* Most common on which type of bacteria? = gram-negative bacteria which has an outer membrane
Function
* Adhesion to host tissues (specificity)
* Contribute to antigenicity
Endospores:
* Cryptobiotic state of dormancy and most durable type of cell found in nature
* Produced by some gram positive bacteria
* Examples of pathogenic genera: bacillus and clostridium
Function
* Ensure survival during adverse environmental conditions
* dormant highly resistant bodies
which of the following bacterial structures may help for the establishment of animal infection?
capsule
plasmid
flagella
ALL OF EM - each’s function will help it in animal infection
Bacterial growth and metabolism
Metabolism: definition?
Metabolism’s currency of energy?
Metabolism: is defined as the sum of all chemical rxn needed to support cellular function and hence the life of an organism
Metabolism -> energy transfer/matter transport (molecule to glucose etc.) -> cellular work -> growth and reproduction
Metabolism’s currency of energy = ATP (e.g. ATP helps flagellum move which in turn makes bacteria move; e.g. for protein to be put into the complex structure again need ATP)
ATP: adenine ribose and 3 phosphate group (when break 1 of the 3 phosphate group gives energy i.e., exothermic so gives u energy)
Bacterial growth and metabolism
how do bacteria grow?
generation time: Length of time required for a single bacterial cell to yield ? (? to ?)
bacterial growth: what are required for the process to occur?
EXAM QUESTION:
can bacteria produce their own nutrition (e.g. carbon etc.) and can they survive on their own?
nutrition: depends on what ? they have inside the chromosome to eat; they need mainly 3 things which are ?
how do bacteria grow? by binary fission
- nucleoid divides; cell wall and membrane begin to form transverse septum
- transverse septum becomes complete
- daughter cells separate
(1 mother cell divides into 2 daughter cells and make septum where 2 membranes form an invagination -> then divide, smtms they cut but smtms dont and so form chains of bacteria)
generation time: Length of time required for a single bacterial cell to yield 2 daughter cells (30 mins to 20 h) e.g. e coli (most pathogens as well) grow v fast
bacterial growth:
specific environmental factors needed for process to occur
- nutrients (e.g. glucose, nitrates, fatty acids)
- pH
- ionic strength & osmotic pressure
- temp.
- gaseous requirement (oxygen, CO2)
EXAM QUESTION:
can bacteria produce their own nutrition (e.g. carbon etc.) and can they survive on their own? - NO, they must get their nutrition from surroundings including protein, carbs and lipids (glucose can be derived from all 3 sources)
nutrition: depends on what enzyme they have inside the chromosome to eat; they need mainly 3 things which are protein, carbs (EASIEST TO PRODUCE ATP FROM) and lipids.
Bacteria has mainly 2 diff. production (glucose)?
pH:
bacteria have diff. range of ? where they can live and multiply. Most of bacteria are ? (neutral pH)
Ionic strength & osmotic pressure:
usually ? solution (solutes inside more concentrated than outside so need to control that)
? solution: solutes outside more concentrated than inside
Most pathogenic bacteria grow best at osmotic pressures equivalent to ? (? NaCl).
Temperature:
Temperature requirement for optimal enzyme-catalyzed metabolic reactions.
Most pathogenic bacteria are ? (30-40 C) and why??
their optimal temp. depends on ?
their temp. range:
psychrophiles
psychrotrophs
mesophils
thermophiles
hyperthermophiles
aerobic and anaerobic (last molecule receiving is not oxygen and its called fermentation - produce acid and gases out of it)
bacteria have diff. range of pH where they can live and multiply. Most of bacteria are neutrophils (neutral pH)
Ionic strength & osmotic pressure
usually hypotonic solution (solutes inside more concentrated than outside so need to control that)
hypertonic solution: solutes outside more concentrated than inside
Most pathogenic bacteria grow best at osmotic pressures equivalent to physiological saline (0.65% NaCl).
Temperature:
Temperature requirement for optimal enzyme-catalyzed metabolic reactions.
Most pathogenic bacteria are mesophils (30-40 C) as the temp. in our blood is the same range (37 C) so adapted to that and hence can multiply etc.
their optimal temp. depends on enzymes
their optimal. range:
psychrophiles: 10 C
psychrotrophs 21 C
mesophils 35 C
thermophiles 60 C
hyperthermophiles 90 C
HOST PATHOGEN INTERACTION
** infection: the ? of pathogens in an individual host **
Until here the infection occurred. The consequence can be:
* ? interaction
* ? relationship
* ?
“imp to understand each step”
expsoure: bacteria present in the exposure site to lumen of intestine
adhesion: bacteria bind to intestine
invasion: enter into intestine
colonization: multiples in cells (NOTE: DISEASE HASN’T YET OCCURED, only multiplication/infection)
toxicity: body doesn’t like bacteria chilling there -> inflammation
tissue damage and disease: NOW ? HAS OCCURED!
The pathogen path…
PATHOGEN
Find a ? host and appropriate ? within the host
Compete ? to adhere to host cells
? host defense
Express ? (? factors) that code for factors causing disease
DISEASE
HOST PATHOGEN INTERACTION
** infection: the invasion and multiplication of pathogens in an individual host **
Until here the infection occurred. The consequence can be:
* Commensal interaction
* Mutualistic relationship
* Disease
“imp to understand each step”
expsoure: bacteria present in the exposure site to lumen of intestine
adhesion: bacteria bind to intestine
invasion: enter into intestine
colonization: multiples in cells (NOTE: DISEASE HASN’T YET OCCURED, only multiplication/infection)
toxicity: body doesn’t like bacteria chilling there -> inflammation
tissue damage and disease: NOW DISESAE OCCURED!
The pathogen path…
PATHOGEN
Find a susceptible host and appropriate niche within the host
Compete microbiota to adhere to host cells
Overcome host defense
Express genes (virulence factors) that code for factors causing disease
DISEASE
Latent period is from when to when?
Infectious period is from when to when?
incubation period is from when to when?
Infection outcomes
No colonization: (does exposure to bacteria occur in this?)
Infection → disease → recovery
Infection → subclinical disease
Infection → disease → death/disability
Infection → disease → persistence (carriers)
Infection outcomes
No colonization: exposure occurs (in all of the ‘em below actually)
Infection → disease → recovery
Infection → subclinical disease (no symptoms but infection occuring inside the host so will have to search for the bacteria)
Infection → disease → death/disability
Infection → disease → persistence (carriers)
bacterial pathogenesis
- ? concept of disease *
severse diseases and death
mild death
BELOW THESE TWO - INSIDE WATER - hence iceberg
subclinical disease => asymptomatic infection (individual infects others, seroconverts, resists re-infection), v low impact
Superantigens
Trigger excessive stimulation of ?
Resulting in ? T-cell ? and ? release. Fever, ?, dermatitis, ?.
SHOCK: is a life-threatening condition that occurs when the body is not getting enough ?. Lack of blood flow means the cells and organs do not get enough ? and ? to function properly. Many organs can be damaged as a result (?).
[antigen-presenting cell (attract ? to kill pathogen)
T cell that comes is similar to the ?]
[FOR SUPERANTIGENS: lymphocyte team react - dont care and just react (it doesn’t have antigen like first one - see pic); many cytokines are produced and make a mess]
Superantigens
Trigger excessive stimulation of T lymphocytes
Resulting in massive T-cell proliferation and cytokine release. Fever, arthrities, dermatitis, shock.
SHOCK: is a life-threatening condition that occurs when the body is not getting enough blood flow. Lack of blood flow means the cells and organs do not get enough oxygen and nutrients to function properly. Many organs can be damaged as a result (organic failure).
[antigen-presenting cell (attract ? to kill pathogen)
T cell that comes is similar to the ?]
[FOR SUPERANTIGENS: lymphocyte team react - dont care and just react (it doesn’t have antigen like first one - see pic); many cytokines are produced and make a mess]
ENDOTOXINS
Bacterial envelope:
outer membrane: only in gram-? bacteria
?: a strong immunogenic molecule (called ?)
in picture lipid A making a mess and ENDOTOXIN IS LIPOPOLYSACCHARIDE
ENDOTOXINS
Bacterial envelope:
outer membrane: only in gram-negative bacteria
Lipopolysaccharide: a strong immunogenic molecule (called endotoxin)
The intravascular release or presence of ? present massive effects on the hosts, and their impact is ?-dependent.
High endotoxin levels can cause ? (organ failure) and ?
Endotoxin in small amounts can induce symptoms of ?, ?, and ?, and ?, finally leading to hypotension.
The intravascular release or presence of LPS present massive effects on the hosts, and their impact is concentration-dependent.
High endotoxin levels can cause shock (organ failure) and intravascular coagulation -> THESE TWO WILL USUALLY LEAD TO DEATH
Endotoxin in small amounts can induce symptoms of fever, inflammation, and leukopenia, and damage to blood vessels, finally leading to hypotension.
Pili/fimbriae
Their presence greatly enhances the bacteria’s ability to ? to the host and establish infection.
Quorum-sensing
* ? communication by small signal molecules (pheromones, autoinducers)
* Effect on ? and other metabolic gene ? control
Low density: autoinducers diffuse away from bacteria promoting ? cell behavior
High density: autoinducers bind to receptors and promote ? behavior
When the bacterial population reaches a defined density (a bacterial quorum), the pheromones attain a critical threshold concentration at which they coordinate ? of bacterial genes, so that the colonizing bacteria act as a community rather than as individuals
Their presence greatly enhances the bacteria’s ability to attach to the host and establish infection.
Quorum-sensing
* bacterial cell-cell communication by small signal molecules (pheromones, autoinducers)
* Effect on virulence and other metabolic gene expression control
Low density: autoinducers diffuse away from bacteria promoting individual cell behavior
High density: autoinducers bind to receptors and promote group behavior
When the bacterial population reaches a defined density (a bacterial quorum), the pheromones attain a critical threshold concentration at which they coordinate expression of bacterial genes, so that the colonizing bacteria act as a community rather than as individuals
