toxina

Toxins are poisonous substances produced by living organisms, including bacteria, plants, animals, and fungi. They can disrupt cellular processes and cause illness or death in other organisms. Toxins may be proteins or small molecules and can act locally or systemically after exposure through ingestion, inhalation, skin contact, or injection.

Biological toxins form a diverse group. Bacterial toxins, such as botulinum neurotoxin and diphtheria toxin, interfere with nerve signaling or protein synthesis. Plant and fungal toxins include ricin and aflatoxins, while many marine and terrestrial venoms contain neurotoxins and cytotoxins. Mycotoxins produced by fungi can contaminate food supplies. The term toxin is typically reserved for substances of biological origin, though in common usage it may overlap with other poisonous substances.

Mechanisms and effects: neurotoxins disrupt nerve function; cytotoxins damage cells; hepatotoxins and nephrotoxins harm liver or kidneys; enterotoxins target the gastrointestinal tract. Dose and exposure route determine risk; some toxins are highly potent in tiny amounts. LD50 values are used to compare acute toxicity in animals. Some toxins have medical uses or are studied for research in small, controlled doses; botulinum toxin is an example.

Prevention, detection and treatment: Diagnosis and treatment rely on history, clinical signs, and laboratory assays. Antitoxins or vaccines provide protection or therapy for certain toxins. Public health efforts include food safety, environmental controls, and regulations on toxins in consumer products and medicines.