TOXINS Study Guide Flashcards
Toxoid
Altered or inactivated toxin. Either by heat or chemical means.
Toxemia
The presence of toxin in blood.
Antitoxin
Usually an antibody proteins that binds to toxin.
Why individuals need to be given toxoid despite the fact the body makes antitoxins.
Because it is used as vaccines to stimulate immune system.
Exotoxin
Synthesized and secreted by gram (+) (-) be bacteria; part of their normal growth and metabolism coded by plasmids or phage DNA( mainly)
Cytotoxin
Neurotoxin
Enterotoxin
Exotoxin
CYTOXIN
Kills/ affects host cell function
Exotoxin
NEUROTOXIN
Impairs neuronal cells, function; causes paralysis.
Exotoxin
Enterotoxin
Alters functioning of the gastrointestinal cell lining, causes intestinal disturbances.
Endotoxin
Lipid A portion of outer membrane LPS of gram negative sps.
Released upon cell damage and cell wall breakage.
All endotoxins produce the same signs and symptoms, through to different degree.
Symptoms include dilation of blood vessels, drop in blood pressure.
Toxins
Harmful substances made by some pathogenic bacteria species. Cause tissue injury/ trigger host immune response
Normally blood or lymph soluble.
Endotoxin and exotoxins in relation to:
Source, relative toxicity, stability and effect in host.
Exotoxin:
Source: gram(-) and positive
Relative
Toxicity: high
Heat stability; unstable at high temp
Effect on host: variable
Endotoxin
Source: gram (-)
Relative
Toxicity: low
Heat stability: stable @1hr, 120 c
Effect on host: fever, shock,coagulation
Exotoxins are made by gram(-) and (+) bacteria.
There are both gram (+) and (-) exotoxins
Identify the various cytotoxins discussed in class.
Hemolysin toxin
Diptheria toxin
Anthrax toxin
Shiga toxin
Anthrax toxin:
(PA)- protective antigen
(LF)-Lethal factor
(EF)- edema factor
Anthrax toxin allows the bacteria to engage the immune system, proliferate, and ultimately kill the host animal.
Is the anthrax toxin chromosomally coded or plasmid coded?
Virulent strains of B anthrax contain 2 large plasmids
1-plasmid encodes the three secretory toxins produced by the bacteria.
Exotoxin:
Shiga Toxin
Potent cytotoxin made by Ecoli 0157H7
A part enters ->endothelial cells->reacts with-> ribosomes->Stops->protein synthesis
Also responsible for hemolytic uremic syndrome.
RBC-> break up-> in tiny blood vessels->results in-> anemia, kidney failure, accompanied by paralysis and nervous system injury signs.
Avoids immune system to one cell to another. Gram negative
Bloody stool
Exotoxin:
Diptheria
Is an exotoxin secreted by corynebacterium diptheriae, the pathogen bacterium that causes Diptheria.
The toxin causes the disease Diptheria in humans by gaining by entry unto the cell cytoplasm and inhibiting protein synthesis.
How do Diptheria toxin get inside cells?
Consists of 2 polypeptides
One polypeptide binds to human growth factor on many types of human cells, triggering endocytosis of the toxin.
Once inside the cell, proteolytic enzymes split the toxin molecule, releasing the second toxin polypeptide into the cytosol.
This polypeptide enzymatically destroys a eukaryotic elongation factor- protein required for translation of polypeptides.
Because the action of the toxin is enzymatic, a single molecule of toxin sequent lay destroys every molecule of elongation factor in a cell, completely blocking all polypeptide sythesis and resulting in cell death.
Diptheria toxin is thus one of the more potent toxins known.
Neurotoxins target
Neurotoxin impairs neuronal cells function: causes paralysis.
Neurotoxins are:
Botulism toxin
Tetanus
Botulism toxin
Toxin belongs to AB- B attached to specific receptor on motor nerve endings
Toxin A- part enters inside, becomes an active peptidade enzyme that degrades a vesicles protein that’s responsible for attachment to cytoplasmic membrane.
Tetanus toxin
Is another disease caused by neurotoxin produced by a species of Clostridium.
Causes prolonged muscular contractions
Complete, unrelenting contraction of the diaphragm results in final inhalation- patients die because they cannot exhale.
Hypokalemia
Loss of water-> lower blood volume due to water loss-> compromises vital organ functioning->
These conditions can produce muscle cramping, lethargy( tiredness), sicken eyes, heartbeat irregularities,kidney failure, coma, and death.
Mycoplasm pneumonia
Strictly aerobic encapsulated mycoplasma
Pleomorphic
Lipid in cytoplasmic membranes called sterols
A feature lacking in other prokaryotes
Contain both RNA and DNA
Binary fusion
Gram positive
Lack cell walls
M. Pneumonia attach to cilia causing it to stop moving up mucus
Bacteria stays in mucus
Close contact it spreads dormitory residents
Treated with erythromycin or tetracycline
Frequent hand washing
No vaccine
Smallest form of life- can squeeze through filters
Fried egg appearance
Mild symptoms
Persistent unproductive cough
Penicillin is not effective
Pneumonia virulence
- capsule ->can protect cells from phagocytosis
- adhesive protein-> is bacteria cell to attach to receptors on the epithelial cell
Chlamydia
- sexually transmitted disease
- RNA and DNA
- non motile and multiply w/in cells
- gram (-)be bacterium, surround each chlamydial cell, but there is no peptidoglycan between membranes
- no cell wall
- transmitted by medical instruments and swimming pools.
- non- motile
- hides in sperm cells
Chlamydia antibiotics
Tetracycline and urthromysin
Then they target bacteria
Ribosomes and protein synthesis
Chlamydia-STD
Sexually transmitted disease:
- non gonococcal urethritis - similar, but minor than Gonnorea
- a symptomatic, common in woman and complication is
PID- pelvic inflammatory disease/ immune response towards infected cells.
Men’s symptomatic- urthirtus painful urination pus and discharge from penis.
bubos- chlamydia
Infection of the lymph nodes painful inflamed lymph nodes.
Ocular disease:
Conjunctivitis trachoma.
- non traumatic blindness in children’s
STD
Lymphogranaloma vererum which is characterized by transient genital lesion at the site of infection on the penis, urethra, scrotum, vagina, cervix, or external female genitalia.
Chlamydia
Binds to conjunctival cells and multiplies within: killing them
Triggers- pus formation
Scars- conjunctiva
Inturn patients- eyelids turn inwards
Eyelashes irritates, scratches and scars cornea
Triggers- blood vessels invasion into clear areas; looses transparency
Leads to- blindness
Cellular morphologies
Elementary bodies
- small, cocci shaped
- infective form; dormant and similar to spores in resistance
- extra cellular form
- reticulate bodies
- large, pleomorhic
- reproductive forms
- intracellular form
Rickettsia
Causes Rocky Mountain spotted fever and transmitted by tick.
Spotted rash on trunks, appendages, palms and soles along with fever, headache, chills, muscle aches
May involve the resp, GI and nervous system; CNS infection may induce convulsions, coma and death.
Rickettsia rickettsii
Non motile
Gram (-)be aerobic intercellular parasite
Unlike chlamydial, has a peptidoglycan cell wall and lipopolysaccharide outer membrane; slime layer is also present
Outside host dies quickly; needs transmission from one host to another
Fragile bacteria
Enters host cell by endocytosis and excited cells by exocytosis
Prevents vehicle fusion with lysosomes to form phagosomes; breaks out of vehicle by enzyme secretion
Slow growing pathogen and divided only 8-12 hrs.
The bacteria remains dormant in ticks salary gland; prolonged feeding makes infective bacteria release into host system
Does not make any toxin the damage is often due to break down of blood vessels
Low blood pressure and insufficient nutrient and oxygen delivered to the body.
Are the anthrax toxin individual sub units?
No they are not.
Diptheria and its action
It’s an exotoxin secreted by corynebacterium diptheriae, the pathogen bacterium that causes Diptheria.
The toxin causes the disease Diptheria in humans by gaining entry into the cell cytoplasm and inhibiting protein synthesis.
2 sub units A-B
Diptheria
Pleomorhic
Non endospores forming
Gram positive
Colonizing the skin and respitory, gastrointestinal, urinary, and genital tract.
Is transmitted from person to person via respitory droplets or skin contact.
Poorer parts of the world that lack adequate immunization.
Individuals are symptomatic
Infections in immunocompromised individuals result in mild respitory disease.
Loeffler’s medium used for Diptheria
Treatment-administration of antitoxin- to neutralize Diptheria toxin before it binds to the cell.
Penicillin or enthromycin kills Cornebacterium, preventing the synthesis of more toxin.
Prevention starts with immunization DYaP
Streptococcus pneumonia
Pneumococcal pneumonia is usually lobar
Affecting one or more lobes of the lungs
Signs and symptoms- fever, chills, congestion, cough, chest pain, which results in short and rapid breathing, nausea and vomiting
Blood frequently enters the lungs, causing coughed up sputum
Gram positive
Normal member of the microbiota of the mouths and pharyngeal of 75% of humans without causing harm.
Known as pneumococcus- short chains
Secretes a cytotoxin called- pneumolysin which binds to cholesterol in the in the cytoplasmic membranes of the ciliates epithelial cells, producing trans membrane pores that result in the lysis of the cells.
Are inhaled occasionally from the pharynx into lungs
S. Pneumonia can pass into the blood and brain to cause bacteremia and meningitis
Damage lining of alveoli allowing erythocytes, leukocyte a, and blood plasma to enter into the lungs
The fluid fills alveoli reducing the ability to transfer oxygen and causing the pneumonia.
Cephalosporin,erythromycin,and chloramphenicol are effective alternatives.
Tetnus neurotoxin
GAVA
Inhibitors
Can’t relax muscle
Botulism
Acitiory
Does not contract
Action of endotoxin
Lipid A portion of outer membrane LP of gram negative sps.
Released upon cell damage and cell wall breakage- MAC and antibiotics
All endotoxins produce the same signs and symptoms, though to different degree
Anthrax
Coded by plasmids
Diptheria
Is coded by chromosomal DNA
Botulism
Enzymatic property
How are toxins grouped based upon structure?
AB sub units
Do the toxin ( botulism) toxin has any peptidade activity and the role.
Yes it does, when it enters in the cell the cell its part A turns into peptidase.
Role of SNARE proteins
Facilitates fusion of target and vesicle membrane.
COX enzyme
Is for the conversion for arantonic acid and catalizes to prostoglandin
Action of Tylenol
Tylenol inhibits COX 3 and acradonic acid is not converted into prostoglandin so you do not get a fever.
How are prostaglandins formed
At aracadonic acid are fatty acids formed in the brain and the prostaglandins are produced following oxidation of aracadonic acid COC enzyme is the catalyst for conversion of aracadonic acid to prostaglandin
Chlamydial
Gram negative
NO CELL WALL
Chlamydia- ocular diseases:
Conjunctivitis trachoma
inclusion trachomatis
Chlamydia-
Lesions in lymph nodes at the groin are
“Bubos”
Diptheria
Thus the polypeptide enzymatically destroys a eukaryotic elongation factor - a protein required for translation of polypeptides. Because the action of the toxin is enzymatic, a single molecule of toxin sequentially destroys every molecule of elongation factor in a cell, completly blocking all polypeptide sythesis and resulting in cell death.
Gram negative
Diptheria, chlamydia, rickettsia
Diptheria
Person to person/ skin contact
A symptomatic
Gram positive
Targets protein sythesis
Cholara
02 El Tor is responsible for the pandemics, but new strains
0139 Bengal
Causing disease
Choleria toxin
Coded by plasmid
Chlymidea
EB- elementary bodies
RT- reticulate bodies
Cholerea
Contaminated water and raw under cooked sea food
Prevention of Cholerea
Boil water, eat only cooked foods
Avoid raw vestibibles and fruit
Wash hands
Shiga toxin
Poor sewage
Inhibits protein sythesis
Kills cells
Cause kidney failed
Attached to surface of neutrophils and is spread by them throughout the body, causing widespread death of host cells and tissues.
Antimicribial drugs induce E. Coli O257:h7 to increase its production of Shiga- like toxin, worsening the disease.
50% of beef carcasses in the U.S.
Bio films
Regular household
Shower curtain, toilet bowl, kitchen sink
Industry: microbes accumulation in pipes, drains and cooling towers
Beneficial as in bio mediation : microbial mediated
Degradation can be enhanced by biofilms
Nature:
Nature:slipperiness of rocks
Biofilms
Biofilms develops as a matrix which allows cells as well as the biofilm to attach
Matrix is made of,
- DNA
- proteins
- fibers of glycocalyces
Biofilms with associated matrix protects members from environmental stress.(uv radiation), antimicribial drugs, pH alterations, temperature and humidity changes.
Concentrate and conserve digestive enzymes
Quorum sensing and biofilms
Quorum sensing is the communication between members
- cells respond to the neighboring cell’s density and secrets molecules.
Biofilms
Develope an extra cellular matrix, composed of DNA, proteins,and primarily the tangled fibers of polysaccharides of the cells glycocalyces.
Biofilm
Receptor blocking drugs have successfully blocked biofilm formation and prevented disease in mice and are being considered for use in humans
Biofilms
Cause up to 70% of bacterial disease in industries countries
Biofilm
Cause prostatitis, kidney infections, tooth and gum decay
Cystic fibrosis, and infections associated with implantation of medical devise.
Rickettsia
Non- motile, gram negative
Peptidoglycan wall
And lipopolysaccharide
Dermacentor
Transmitted by tick
Rickettsia
Convulsions, coma and death
Enters and exits cells by endocytosis and exits cells by exocytosis.
Does not make any toxin
Relationship amongst organism
Antagonistic (harmful)
Synergistic ( beneficial)- symbiotic- Complex
Symbiotic relationship: organisms lives in close contact(physically or nutritional)
Complex;
Biofilms are cooperative; benefits are amplified
- many bacterial diseases are due to this kind of relationship.
Ex: microbes of different species are attached to tooth surface, mucous membrane of intestine and other body areas.
Lag phase
- no appreciable change in cell number; extend from few hours to few days
- cells exhibits intense metabolic activity increased sythesis of proteins, cell wall component
Phospholipids
Protein synthesizing machinery-
Exhibits maximal activity C in media from glucose to lactose-
Log phase
- period of rapid growth at exponential rate.
- cells are metabolically active; cells divide at constant rate
Generation time- tuberculosis drug needs to be taken for a long time to target Micolic synthasis
- medically important because drugs have more of an impact on the bacterial growth. They are more sensitive.
- plot is a straight line; cells in mid exponential phase are valuable for researchers.
Chemostat
Apparatus that keeps the cells in the log phase of growth.
( maintains the cells in the log phase)
- inlate valve - fresh medium
- outlet valve- dead cells and used
Stationary phase
- growth rate slows; new cells produced at the same rate a sold cells die
Limited resources
- Consumption of essential nutrients
- Waste products accumulation at toxic level
- pH changes
Death phase
- population enters this phase when dying exceeds number of new, viable cells
- progressive in some; alternately called as the logarithmic decline phase
- continues until small proportion of the cells remain or population dies out entirely
- endospores are formed
Nutrient uptake
Passive process-substance movement is from high consent ration to a region of low concentration
- no expenditure of cellular energy
Active/ functions when bacteria are low in nutrient environment
- there is expend entire of cellular energy
Active transport
Involves substance movement from outside to inside
Against conc gradient
- substance that cross membrane is not altered
Group translocation
Cells picks up substance even though they are in lower cincentration outside
-substance altered during transport: prevents from leaving cell
Ex: glucose utilization by the phosphor transferase system purine
Pyramided and long chain fatty acids transport
Rickettsias
Cultivated in eggs
Chlamydia
Birds eggs
Treponema
Testicle of rabbit
Nitrogen
Used for back bone in prodigy an sythesis. Emine group for emio acids.
Phosphorous
Phospholipid/ phosphorlization in ATP
Sulfur
Proteins for electron transport chain. Amino acid sulfer containing amino. Trace- iron/ zinc/ copper/ cobalt/ manganese
Alpha hemolysis
Incomplete destruction
Beta hemolysis
Complete destruction
Gamma
Streptococcus - no defect on the red blood cells
Growth factors
The necessary organic chemicals are called growth factors.
Vitamins are growth factors
Iron is essential element for the growth and development of all the scale of living organisms.
Iron
Oxygen transport, ATP generation, cell growth and proliferation, and detoxification.
Autotrophs
They feed themselves
Make organic compounds from co2 and thus need not make it from other organisms.
Toxic forms of O2
Singlet 02-
Molecular oxygen with electrons that have been boosted to a higher energy state, typically. Very reactive
Superoxide radical
A few superoxide radicals from during the incomplete reduction of O2 during electron transport in aerobes.they are so toxic that aerobic organisms must produce enzymes called super oxide did mutates to detoxify them.
Hydroxyl radicle-(oh)
Results from ionizing radiation and from the incomplete reduction of hydrogen peroxide.
Peroxide anion
Hydrogen peroxide formed during reactions catalizes by superoxide dismisses contains peroxide anion, another highly reactive oxidant.
The types of anaerobic media
Non-selective blood agar medium
And gas pack medium
Defined medium
Known
Complex
Unknown
Enrichment media
Low level to detectable level
