Bacterial toxins can come from a variety of sources including soil, food, and intestinal tracts of animals. They are classified based on their activity (emetic, neurotoxic, enterotoxic) and origin (exotoxins and endotoxins). Common pathogenic bacteria that produce toxins include Bacillus cereus, Clostridium botulinum, C. perfringens, Staphylococcus aureus, and cyanobacteria. Their toxins can cause illnesses like botulism, food poisoning, and toxic shock syndrome. While harmful, some bacterial toxins are being investigated for potential medical applications in cancer treatment and pest control.

2. Bacterial Toxins

3. Sources
Sources and reservoirs : soil, mud, water and intestinal tracts of animals
Foods:
• Improperly canned low-acid foods(green beans, corn, beets, asparagus,
mushrooms, spinach)
• Smoked fish and fermented food
• Improperly home cured hams
• Flavoured oil and oil infusions
 In 1993, FDA required acidification of such preparations to prevent the
growth of Clostridia.

4. Classification
1. On the basis of activity
Emetic toxins (i.e., Bacillus cereus)
Neurotoxins (botulinum toxin)
Enterotoxins
Cytotoxic enterotoxins
Cytotonic enterotoxins

5. 2. On the basis of origin
Exotoxins are synthesized and released
(usually by Gram-positive bacteria) and
are not an integral part of the organism,
but may enhance its virulence Eg.
diptheria, tetani toxin
Endotoxin is generally a
lipopolysaccharide membrane constituent
released from a dead or dying Gram-
negative bacteria, these toxins are
nonspecific and stimulate inflammatory

6. Bacillus cereus
• Gram-positive
• Spore forming rod
• Aerobe
• Cause foodborne illness causing severe nausea, vomiting and diarrhoea
• Reservoirs: soil and dust.
Toxins
Emetic thermostable toxin Diarrheagenic thermolabile toxin
• Can survive at 126°C
for 90 min
• Small cyclic peptide
that acts on 5-HT3
receptors stimulating
vagus afferent nerve
• Serotypes: 1,3 and 8
• Can survive at 56
°C for 20 min
• associated with
diarrhoea and
gastrointestinal pain
• Serotypes:
1,2,6,8,10 and 19

7. Foods associated
• Emetic form: boiled and fried rice
• Diarrheal form: wider occurrence and
may be found in meats, stews, pudding,
sauces, dairy products, vegetable dishes,
soups, and meatloaf
Confirmed by the isolation of more than 105 B. cereus organisms
per gram from epidemiologically implicated food, but such testing
is often not done because the illness is relatively harmless and
usually self-limiting.
Diagnosis
Most emetic patients recover within 6–24
hours
Prognosis

8. Botulinum toxin (Neurotoxin)
• Produced by the Clostridium
botulinum
• Anaerobic
• Gram-positive
• Spore-forming rod
• Commonly found on plants, in soil,
water and the intestinal tracts of
animals
• Food botulism rarely causes illness
• Botulinum toxin:
• Toxins A,B,E and F in humans
• C. butyricum (Type E only) and C.baratti ;toxins C and D in animals
• Type G has not caused any human cases
• Symptoms:
• Drooping eyelids
• Double vision
• Inability to make facial expression
• Difficulty in swallowing
LD50 - 1.3–
2.1 ng/kg IV or IM and
10–13 ng/kg when
inhaled

9. Clostridium perfringens (Enterotoxin)
C. perfringens is classified into five types (A–E) depending
upon their ability to produce alpha, beta, epsilon, and eta toxin
• Primary Reservoir: intestinal tract of warm-blooded animals
(including humans)
• Food poisoning associated with consumption of roasted meat
that has been contaminated with intestinal contents at
slaughter, followed by roasting and inadequate storage.
• Foods associated with C. perfringens poisoning include
cooked meat or poultry, gravy, stew, and meat pies. C.
perfringens is also associated with the production of another
11 toxins, including those associated with gas gangrene.

10. Staphylococcus aureus
• Dangerous and versatile pathogen that can cause a
multitude of different diseases
• Exoproteins: toxic shock syndrome toxin-1 (TSST-1), the
exfoliative toxins ETA and ETB, leukociden and the
staphylococcal enterotoxins
• Sources: nose and throat discharges, hands and skin,
infected cuts, wounds, burns, boils, pimples, and faeces
• Primary reservoirs: anterior nares of humans
• Other reservoirs:
• Mastitic udders of cows (contamination of
unpasteurized milk)
• Bruised tissues of poultry
• Food contaminated after cooking
• Keeping food items at room temperature for several
hours
• Foods associated:
• poultry and dressing; sauces and gravy;
• Cream filled pastry, potatoes, ham, poultry, fish
salads, milk, cheese and generally high protein

11. Staphylococcal enterotoxins (SE)
• Emesis is produced as the result of stimulation of the putative SE
receptors in the abdominal viscera, following which is a cascade of
inflammatory mediator release
• Properties:
• ability to cause emesis and gastroenteritis in primates
• Superantigenicity
• intermediate resistance to heat and pepsin digestion

12. Toxic shock syndrome toxin-1 (TSST-1)
• Characterized by low blood
pressure, fever, diarrhoea, an
extensive skin rash, and shedding
of the skin.
• TSS results from the massive
overproduction of cytokines by T
cells induced by the TSST-1.
• TSST-1 binds both class II MHC
receptors and T-cell receptors,
stimulating T-cell responses.
• TSST-1 is a superantigen.

13. Cyanotoxins are generally grouped according to their site of action into
hepatotoxins, neurotoxins, and dermatotoxins
• hepatotoxins are the microcystins, which are produced by a number of
cyanobacterial species
• including species in the Microcystis, Nostoc, Oscillatoria, and Anabaena genera
• produce liver damage through binding to and inhibiting serine/threonine
phosphatases, leading to hyperphosphorylation of proteins and disruption of
hepatocyte structure and function
• Death is caused by hemorrhagic shock which follows the breakdown of liver
circulation and accumulation of blood in the liver
• At lower chronic exposures, microcystins lead to chronic inflammation.

14. • BMAA, another neurotoxic cyanotoxin, stimulates glutamate receptors and has been
hypothesized to be a causative agent in lytico-bodig, the neurodegenerative disease
endemic to Guam.
• Saxitoxin, a sodium channel blocker, is also produced by some cyanobacteria (as well
as by some dinoflagellates)
• Cyanotoxins have been determined to be responsible for toxicity to both wildlife and
to domestic livestock.
• Growth of cyanobacteria has been observed to reduce growth of green algae as well as
aquatic plants such as duckweed and elodea

15. Toxin Disease Symptoms
Diphtheria toxin
Corynebacterium
diphtheriae
Diphtheria Begins with sour throat and fever, painful
swallowing, difficulty in breathing,
formation of grey pseudo membrane
covering the tonsils
Tetanus toxin
Clostridium tetani
Tetanus Tetanic spasms,
fever, sweating, headache, trouble
swallowing, high blood pressure, and
a fast heart rate
Cholera toxin
Vibrio cholerae
Cholera watery diarrhoea leading to
severe dehydration and electrolyte
imbalance.
Pertussis toxin
Bordetella pertussis
Whooping cough initial symptoms similar to common
cold with followed by weeks of severe
coughing fits.
Other bacterial toxins

16. Toxins can function in multiple ways,
by inhibiting protein synthesis (diphtheria toxin),
• activating second messenger pathways (Bacillus anthracis edema factor or cholera
toxin),
• activating immune responses (S. aureus superantigens),
• damaging cell membranes (E. coli hemolysin),
• by general action of metalloprotease activity (Clostridium tetani tetanus toxin).

17. Applications of bacterial toxins
• Bacterial toxins are proteins capable of achieving multiple remarkable tasks. They
function as autonomous molecular devices, targeting specific cells in an organism,
punching holes in their membranes, or modifying intracellular components.
• Bacterial toxins, which are primarily harmful, are also being used for the cure of
cancer, killing of mosquito larvae.

18. MYCOTOXIN

19. INTRODUCTION
 A mycotoxin is a toxic secondary metabolite which is produced by organisms of
fungi kingdom , commonly known as molds.
 One mold species may produced many different mycotoxins, and the same
mycotoxin may be produced by several species.
 Mycotoxins are associated with human disease and cause acute and chronic effect.

21. Factors affecting the production of
mycotoxin
 Physical factors
Temperature between 40 C to 90
Humidity more then 70%
Moisture (22- 23%)
 Chemical factors
Nutritional factors, including inorganic ions
Use of fungistats
 Biological Factors
Strain of organism
Microbial detoxification

22. Mechanism
 Bind to DNA and RNA
 Oxidative stress
 Alter protein synthesis and function
 Alter cell membrane function and transport
 Alter apoptosis

24. Types of mycotoxin
 Aflatoxin : B1, B2 , G1and G2
 Ochratoxin : Ochratoxin A , Ochratoxin B ,Ochratoxin C
 Citrinin
 Ergot Alkaloids
 Patulin
 Fusarium : Fumonisins , Trichothecenes, Zearalenone.
 T-2 toxin, Deoxyniba-lenol
 Deoxynival- lenol(DON)

25. Mushroom toxins
 Toadstools are non-edible
 Amanita caesarea (Caesaer’s mushroom)
 Amanita Palloides (Death cap)
 Amanita muscaria (Fly agaric)
 contain amatoxins, heat-stable peptides
 amatoxins is the inhibition of RNA polymerase,
 leading to a blockade of protein synthesis.

26. Health effects of mycotoxins
 Mycotoxins ae believed to be among the most potent known carcinogen.
 Effect ranges from immediate toxic responses and immunosuppression to
potential long-term teratogenic, estrogenic and estrogenic.
 Food poisoning
 Inhibition of protein synthesis
 Increase of tryptophan in blood and brain
 Nausea , vomiting
 Abdominal pain , diarrhoea
 Breast enlargement in boys
 immunosuppressor

27. Application of mycotoxins
 Medical application
Trichothecenes are known to possess antileukaemic activity.
Zearalenone derivatives have been considered as potential treatment for menopausal
syndrome in women.
 Agricultural applcations
Derivatives of zearalenone as growth promoter n sheep and cattle ; other have been
used as herbicides and insecticides.

28. PLANT TOXINS

29. INTRODUCTION
• Scientist have been aware of existing secondary plant products for many years. These are
basically chemicals which are manufactured by plant but do not seem to play any role in
metabolism, growth, and other life processes.
• These products of plant are toxic or repellent to herbivores and microbes and help defending
plant producing them. They are evolved as defence mechanism.
• First secondary plant product to be isolated and studied is “ MORPHINE’’ in early 1800s .
-> The classes of secondary metabolites are :-
1. Alkaloids
2. Terpenes and Terpenoids
3. Glycosides

30. PLANT ALKALOID
• “Alkaloid” refers to diverse group of chemicals of botanical origin which contain heterocyclic
Nitrogen and are generally derived from amino acid.
• Examples of alkaloids are :- cocaine , caffeine , nicotine , morphine , atropine , capsaicin ,
strychnine.
• CAFFEINE
• Caffeine along with its relatives theophylline and theobromine is a xanthine alkaloid and its
physiological effects have been known for centuries: were first deduced from observations of
effects of coffee berries on livestock.
• Xanthines are found in multiple plants including coffee plants , where they probably act to
discourage pests from feeding on plant and inhibit germination of other plant in the
surrounding soil.
• The three xanthines are also found in tea plant [camellia sinensis] and theobroma cacao, the
plant whose seeds are used to produce chocolate.

32. PHARMACOLOGICAL ACTIONS
• Caffeine is responsible for BLOCKADE OF ADENOSINE RECEPTORS which play a role in
modulating release of several neurotransmitters {including dopamine , acetyl choline ,
glutamate, GABA}
• Adenosine receptors are G – Protein coupled receptors and come in four subtypes. Caffeine
has highest affinity for A1 and A2 receptors; activation of which leads to suppression of
neuronal activity.
• Ubiquity of adenosine receptors in brain leads to diverse effects of caffeine to increase
alertness, improve mood , decrease reaction times.
• Caffeine also increases anxiety.
• Chronic consumption is linked to reduction in risk for development of dementia and
adenosine receptor blockade.
• Discontinuation of chronic caffeine intake :- withdrawl symptoms will be seen. This is due to
the adenosine receptors upregulation and increase in number that occur in response to
chronic induced adenosine receptors blockade.
• Once exposure ceases there is a period of time before compensatory downregulation
restores receptor balance. In that interim overabundance of adenosine receptors can lead to
other effects i.e increase in cerebral vasodilation which produces classic caffeine withdrawl
headache.

33. • CAPSAICIN
• It is another alkaloid which is found in plants of genus capsicum , defence against herbivores.
• Capsaicin is an agonist at a receptor called transient receptor potential vanilloid 1 receptor
(TRPV1).
• This receptor is found in variety of areas of mammalian brain and play a role in heat and pain
pathways .
• Binding of capsaicin to receptors:- induces refractory state , it is used in analgesic
preparations. ( although used in combination with other anasthetics to block any unpleasant
irritant sensation.

34. TERPENES AND TERPENOIDS
• Defense mechanism used by plant is production of “latex” a complex fluid released upon
injury containing terpenes and terpenoids.
• POINSETTIA – A common holiday plant rocketed into notority on the basis of 1944 book
reporting unconfirmed death of child followed by ingetion of leaf.
• Terpenoids in poinsettias have the potential to irritate human skin – CONTACT DERMITIS

35. PLANT GLYCOSIDES
• Amygdalin [in almond] and Linamarin [in cassava plant] are classified as cynogenic
glycosides. These compounds serve defensive functions, in that if plant is attacked then;
cynogenic glycoside is broken to release Hydrogen Cyanide.
• Still it is seen that Cassava root is major source of food in Africa but it must be processed in
order to remove all the traces of glycosides.
• Digoxin and Digitalis are steroidal glycosides found in fox glove. These are basically cardiac
glycosides and are Na+/K+ ATPase blockers and have been used to treat variety of
cardiovascular conditions due to effects on myocardial contraction and conductibility.

36. OTHER IRRITANTS
• Dieffenbachia species are examples of plants capable of causing irritation. Colloquially k/a
“dumb cane”, these if ingested can produce pair of swelling of mouth , tongue, and oral
cavity. This effect has long been attributed to the crystals of Calcium Oxalate (Raphide) which
are found in plants.
• Raphides are found in Daffodils and also along with variety of alkaloids produce “Daffodils
itch” which is common complaint of florists
• Sap of stinging nettles (Urtica species) contains a complex mixture of chemicals including
formic acid, acetylcholine, and histamine which its stinging hairs (trichomes) can inject into
organisms unfortunate enough to brush up against it.

37. 1) Dieffenbachia plant
2) Stinging nettles of urtica
species

38. POISON IVY AND ALLERGIC CONTACT
DERMATIS
• Allergic contact dermatis involves interaction
of plant constituents with immune system to
produce an allergic reaction. The plant
widely known for this is POISON IVY, (genus-
toxicodendron)
• Common In North America ,these are
responsible for millions of allergic contact
dermatis cases per year.
• Urushiol is found in roots, leaves and stems
of toxicodendron spp. Upon contact with the
chemical a rash type develops within a day
or two of exposure which will resolve within
2-3 weeks.

39. TOXINS OF
INVERTEBRATES

40. CNIDARIA
Chironex fleckeri(box jellies)
• Long poisonous tentacles
• Nematocyst contains venom injected
either to prey ,defense or predate.
• Shoot out spine-tipped,coiled tubule
and delivers toxin.
• Venom composition:-
proteins(cytolytic)and cardiotoxic
components.

41. • Significant toxins:- Toxin -1 (CfTX-1)and Toxin-2 (CfTX-2) share
features with pore forming toxins.
• Mechanism of action :- Pore formation and effect on ion
channels
• LD50 values of toxins of jellyfish is between 30 and 300
micrograms per kg.
• Symptoms:-painful sting,cardiovascular complication,
hypertension, hypotension, arrhythmias,respiratory arrest.

42. Physalia physalis(Portuguese man ‘o’war)
• Sting extremely pain rather than lethal.
• Colony made of 4 types of zooids:-
• 1-polyp(dactylozooids – form tentacles 20 m long)
• 2-polyp(pneumatophore-gas filled member used to swim
.
• 3-polyp(for feeding) and 4-polyp(for reproduction).
Nematocyst conatains- enzymes,catalytic
peptides,neurotoxins.
Symptoms-severe pain,allergies,fever,shock,cardiac
problems.

43. Arthropodes
Class –Arachnida
Australian funnel web spiders
• Belong to Atrax genus ,large ,dangerous to
humans .
• Venom toxic to Na+ ion channels 》Massive
release of neurotransmitters 》hypertension》
edema》intracranial hypertension and death
of prey.
• Ca+,,Na+,K+channel blockers.

44. Class –Arachnida and Diplopoda
Brown recluse spiders (Loxosceles
reclusa)
• Necrotic venom rich in –sphingomyelinase,
• protease,phosphplipase and
hyaluronidase.
• Symptoms-
itching,swelling,oedema,necrotic
area formed.
Millipedes
• Segmented body,release toxins
when pressed.
• Body fluids contains
toxins(cyanide & quonones)
• Symptome-mucous membrane
inflammation,blackish brown
hyperpigmentation lesion.

45. Scorpions –the deadliest
The death stalker (Leiurus quinquestriatus)
• It is one of the most venomous scorpion.
• Venom is a mixture of deadly neuro toxins.
• Person will experience extreme
pain,convulsions, paralysis and even death
due to cardiac and respiratory failure.

46. Mollusks
Cone snails (Conus spp.)
• Venome contains a group of peptides called
conotoxins.
• Conotoxins mechanism of action-rich in
• disulfude bonds ,target Na+,Ca+,K+channels,nicotine
and Ach receptors
• Have high specificity for binding to targets only in 1
type of prey.
• Clinical importance :- Ziconotide in clinical trials for
use in pain management.

47. Blue-ringed octopus(Hapalochlaena
maculosa)
• Uses toxins for prey capturing and defense.
• Main component of venom is Tetradotxin(TTX).
• TTX also found in skin of octupus.
• Mechanism of action:-TTX blocks the generation
of action potential and blocks Na+ channels .
• LD50 of tetradotoxin in mice is around 300
micrograms per kg.
• Symptoms:-weakness,numbness,ataxia,higher
doses cause paralysis,respiratory arrest and
parenthesis.

48. Puffer fish secretes
Tetrodotoxin is a sodium
channel blocker.
Stingrays possess barbed and serrated spines which
also feature toxin-producing cells.
These cells sustain damage when the spine is thrust
into target tissue, and some of the toxin enters the
wound.

49. Neotropical poison dart frogs ( Dendrobates spp. and Phyllobates spp.). These small, brightly colored
frogs secrete alkaloids including batrachotoxin, which locks sodium channels in an open position.
Toad secretions can contain epinephrine, norepinephrine, GABA, and
serotonin, bufotenine, a hallucinogenic compound. Some new tissues, contain
tetrodotoxin.

51. • Snake venom is produced in venom glands in the upper jaws and
is delivered through ducts to the base of enlarged teeth (fangs).
• These teeth often contain grooves, which may be open or closed,
and through which the venom flows and is delivered upon biting.
Viperidae, the fangs are basically hollow.
• Actual injection of venom is produced by action of a muscle on
the venom gland and is under the control of the snake.
• Snakes typically deliver doses of venom that may be in the range
of 100 times the lethal dose for their prey.

52. Snake venoms the non-enzymatic polypeptides
• Dendrotoxins (from mamba venoms) which are potassium channel blockers
• Cardiotoxins (from cobra venoms) which produce red cell hemolysis
• Erabutoxins (from sea snake venom)Cobratoxins which block the nicotinic
acetylcholine receptor
• Crotamine (from rattlesnake venom) which acts on sodium channels.
Antivenom
• Monovalent (specific for one species) or polyvalent (active against several species,
typically from the same region). Patient may suffer a hypersensitivity reaction

53. Gila monster
Mexican beaded lizard cobra
mambas
Rattle Snake