• Main toxin: Tetrodotoxin (TTX) – one of the most potent natural poisons, molecular formula: C₁₁H₁₇O₈N₃. Even a very small amount can be fatal to humans.

• Occurrence: The toxin is mainly concentrated in the eggs, intestines, abdominal muscles, and seminal vesicles of the pufferfish. Its concentration and form vary depending on the species, living environment, and the specific organs of the fish.

• Harmful effects on humans:

  • Nervous system and muscles: numbness of lips, tongue, and fingers; muscle weakness; paralysis.

  • Respiratory system: paralysis of respiratory muscles → respiratory failure → death.

  • Cardiovascular system: bradycardia, hypotension, arrhythmias.

  • Digestive system: nausea, vomiting, abdominal pain, diarrhea.

• Origin: Clostridium tetani is a Gram-positive, anaerobic, spore-forming bacterium found in soil, dust, and animal feces; it commonly enters the body through open wounds [4].

• Toxin: Tetanospasmin (also known as tetanus toxin, TeNT) — a neurotoxic exotoxin [5].

• Form of existence: The exotoxin is secreted after spores germinate in anaerobic tissues of the body; spores themselves can persist for long periods in the environment [4][6].

• Harmful effects:

  • Causes tetanus, with typical symptoms including lockjaw (trismus), seizures, and generalized muscle rigidity, which may lead to death [4][5].

  • Mechanism: The toxin inhibits the release of inhibitory neurotransmitters (GABA, glycine) in the central nervous system → causing continuous, uncontrolled muscle contractions.

*Form of existence:

-   Amatoxins exist as stable cyclic peptides. They are relatively heat-resistant and not easily destroyed by cooking.

-   They are organic chemical compounds, not independent alkaloids or amino acids, but products derived from protein precursors.

-   Toxin-bearing parts: The entire mushroom (cap, gills, stem, base).

*Harmful effects:

- Causes necrosis of the liver and kidneys.

-   Can lead to death.

• Toxin: Amygdalin → releases hydrogen cyanide (HCN).

• Form of existence: Concentrated in the seed kernel; toxic only when chewed/crushed and metabolized.

• Harmful effects: Small amounts have little effect; large doses cause cyanide poisoning → dizziness, breathing difficulty, arrhythmia, potentially fatal.

• Toxin: Amygdalin → releases hydrogen cyanide (HCN).

• Form of existence: Concentrated in the seed kernel; toxic only when chewed/crushed and metabolized.

• Harmful effects: Small amounts have little effect; large doses cause cyanide poisoning → dizziness, breathing difficulty, arrhythmia, potentially fatal.

Form of existence: Present throughout the plant (leaves, flowers, roots, stems); soluble in organic solvents and easily absorbed via the digestive tract.

Harmful effects: Extremely poisonous; even a few leaves can be fatal. Symptoms include dizziness, nausea, muscle paralysis, convulsions, and respiratory failure → rapid death if not treated promptly.

Form of existence:

- By-product in the production of herbicides/pesticides.

- Highly stable in the environment; accumulates long-term in soil, water, and animal fat.

Harmful effects:

- Causes endocrine disruption, liver damage, and cancer.

- Leads to birth defects and genetic effects across generations.

Form of existence:

Colorless, volatile, odorless liquid.

Artificially synthesized, formerly used as a chemical weapon.

Harmful effects:

Inhibits the enzyme acetylcholinesterase → accumulation of acetylcholine at synapses.

Causes seizures, muscle spasms, respiratory failure → rapid death.

Tú Ngọc: https://docs.google.com/document/d/14Sq0OuuLG5VD1q6NG4TF97qkwTsrSOlo/edit?usp=drivesdk&ouid=103276240476722599701&rtpof=true&sd=true