Module 3 Flashcards
Is a poisonous substance that is specific product of the metabolic activities of a living organism and is usually very unstable, notably toxic when introduced into the tissues, and typically capable of inducing antibody formation.
– These chemicals compounds have diverse structures and doffer in biological function and toxicity.
Toxin
The ability to cause disease
Pathogenicity
TRUE OR FALSE
- These toxins are harmful to the organisms themselves, but they may be toxic to other creatures, including humans, when eaten.
False (Not harmful)
- They can be small molecules , peptides, or proteins that are capable of
instigating disease on contact with or absorption by body tissues interacting with
biological macromolecules such as enzymes or cellular receptors. - These substances can be made by living cells, organisms, plants, fungi, animals, elements, and metals that are capable of causing disease when introduced into the body tissues
Toxin
-The ability of a pathogenic organism to produce injurious substances that damage the host.
- an underlying mechanism by which many
pathogens produce diseases.
- an important virulence mechanism/determinant for
many microbial pathogens
Toxigenicity
toxinosis in which the toxin is spread by the blood from the site of infection (as in tetanus and diptheria);also the condition caused by toxins that have entered the blood of the host
Toxemia
The extent of pathogenecity
Virulence
Antibodies against a specific toxin
Antitoxin
CLASSIFICATIONS OF TOXINS
(IN TERMS OF THE TOXIGENIC ORGANISM)
e.g. stx phage, cytotoxins, lysins
Viruses
Diseased caused actions to toxins
- e.g. staphylococcal skin scalded syndrome (SSSS), toxic shock syndrome (TSS), food poisoning
Toxicosis/toxinosis
What are the types of biotoxins?
Mycotoxins (fungi)
Zootoxins (animals)
Phytotoxins (plant)
toxinoses caused by the ingestion of pre-formed toxins (e.g. botulism)
Intoxication
CLASSIFICATIONS OF TOXINS
(IN TERMS OF THE TOXIGENIC ORGANISM)
e.g. endotoxins, exotoxins
Bacteria
CLASSIFICATIONS OF TOXINS
(IN TERMS OF SITE OF ACTION)
- nerve tissues
- damage, destroy, or impair the function of the central or peripheral nervous system.
- It may damage neurons, axons and/or glia, resulting in loss of specific nuclei and/or axonal tracts or demyelination.
- Neurotoxic effects include behavior changes, seizures, altered sensations, tingling or numbness in the limbs, memory loss, and even death.
neurotoxins
Inactivated toxin used in a vaccine
Toxoid
CLASSIFICATIONS OF TOXINS
(IN TERMS OF SITE OF ACTION)
- Enteric system
- Secreted polypeptides that change the enterocyte or colonocyte trans membranous salt and water transport mechanisms without causing structural mucosal damage.
- They elicit their primary effects in the intestinal tract, initiating a metabolic cascade.
- are cytotoxic and kill cells by altering the
apical membrane permeability of the mucosal epithelial cells of the intestinal wall
enterotoxins
CLASSIFICATIONS OF TOXINS
(IN TERMS OF THE TOXIGENIC ORGANISM)
e.g. tricothecenes
Fungi
CLASSIFICATIONS OF TOXINS
(IN TERMS OF SITE OF ACTION)
- Cells
- Any substance that has a toxic effect on important cellular function
- Different kinds of cytotoxins work in different ways - e.g. make holes in the cell membrane - lysis.
- Examples: venom
Cytotoxins
CLASSIFICATIONS OF TOXINS
(IN TERMS OF THE TOXIGENIC ORGANISM)
endotoxin, phospholipase, protease
Protozoa
CLASSIFICATIONS OF TOXINS
(IN TERMS OF SITE OF ACTION)
Blood cells, blood vessels
Hematotoxins
CLASSIFICATIONS OF TOXINS
(IN TERMS OF THE TOXIGENIC ORGANISM)
microcystins, PSP
Algae
CLASSIFICATIONS OF TOXINS
(IN TERMS OF SITE OF ACTION)
Damage skin, mucous membranes, or both, often leading to tissues necrosis
Dermatoxins
CLASSIFICATIONS OF TOXINS
(IN TERMS OF THE TOXIGENIC ORGANISM)
alkaloids, tannins, cyanogenic glycosides
Plants
CLASSIFICATIONS OF TOXINS
(IN TERMS OF THE TOXIGENIC ORGANISM)
fish, insects, snakes, frogs
Higher animals
CLASSIFICATIONS OF TOXINS
(IN TERMS OF SITE OF ACTION)
Liver tissue
Hepatotoxins
tetrodotoxin block the entrance of the sodium gate.
Fugu toxin
CLASSIFICATIONS OF TOXINS
(In terms of source of origin (PLANT TOXINS))
- play a major role in disease production and produce all or most of the symptom’s characteristic of the disease in susceptible plants.
- mostly produced by pathogens during pathogenesis.
- e.g. victorin from Cochliobolus victoriae/Helminthosporium victoriae,
the causal agent of Victoria blight of oats (a host-specific toxin)
Pathotoxins
CLASSIFICATIONS OF TOXINS
(In terms of source of origin (PLANT TOXINS))
- substances produced in the host plant due to host-pathogen interactions for which a causal role in disease is merely suspected rather than established; products of parasites.
- non-specific and no relationship between toxin production and pathogenicity of disease-causing agent.
- e.g. alternaric acid - Alternaria solani
Phytotoxins
binds to the interior portion of the
sodium channel.
Scorpio toxin
CLASSIFICATIONS OF TOXINS
(In terms of source of origin (PLANT TOXINS))
- substances produced in the infected host by the pathogen and/or its host which functions in the production of the disease, but is not
itself the initial inciting agent of the disease.
- e.g. Fuscaric acid: wilt-causing Fusarium sp.
Vivotoxins
cause spastic paralysis - the
muscle stays in contraction.
Tetanus toxin
CLASSIFICATIONS OF TOXINS
(In terms of specificity of toxins (PLANT TOXINS)
- metabolic products of the pathogens which are selectively toxic only to the susceptible host of the pathogen.
- produce all the essential symptoms of the disease.
- e.g. victorin - oats
- e.g. amylovorin - antibacterial against Lactobacillus
Host-specific/ host-selective
CLASSIFICATIONS OF TOXINS
(In terms of specificity of toxins (PLANT TOXINS)
- metabolic products of the pathogens, but do not have host specificity and affect the protoplasm of many unrelated plant species that are normally not infected by the pathogen.
- produce few or none of the symptoms of the disease.
- e.g. fusaric acid
- e.g. piricularin - rice and wheat
Non-specific/ non-selective
CLASSIFICATION OF TOXINS
(In terms of location (MICROBIAL TOXINS))
- true intracellular (e.g. cholera toxin, pertusussis toxin)
- surface-bound (e.g. the LPS- protein toxin or endotoxin of Gram-bacteria)
Cell-bound
CLASSIFICATION OF TOXINS
(In terms of location (MICROBIAL TOXINS))
* entirely extracellular (e.g. Diphtheria toxin)
- Partly extracellular during the log phase (Bot toxin)
Extracellular
Present in more that 200,000 species spread through major phyla, including arthropods, mollusks and chordates
Animal poisons
A toxin within the animal’s tissues that can have deleterious effects when ingested.
Poison
Produced in specialized glands or cells and delivered either by biting or by stinging, or in some cases by spitting.
Venom
- It contains both anti-inflammatory and
inflammatory compounds, including
enzymes, sugars, minerals, and amino
acids - melittin, histamine and other biogenic
amines which contribute to pain and itching
Bee venom
- group of neurotoxic peptides isolated
from the venom of the marine cone
snail genus Conus - peptides consisting of 10 to 30 amino
acid residues, typically have one or
more disulfide bonds - Dr. Lourdes J. Cruz, Filipino
National Scienist - biochemistry
of conotoxins
Conotoxins
– first painkiller
derived from cone snail toxin
approved by US-FDA in 2004
marketed as Prialt
Ziconotide
inhibits the inactivation of voltage-dependent sodium channels
δ-conotoxin
- blocks action potentials in nerves by
binding to the voltage-gated, fast sodium
channels in nerve cell membranes, essentially preventing any affected nerve cells from firing by blocking the channels used in the process. - binding site of this toxin is located at the pore opening of the voltage-gated Na+ channel.
Tetrodotoxin
inhibits nicotinic acetylcholine receptors at nerves and muscles
α-conotoxin
a peptide isolated from the venom of the Brazilian viper, was the lead compound for
the development of the antihypertensive agents cilazapril and captopril
Teprotide
inhibits potassium channels
κ-conotoxin
tobacco plant produce a
substance called blank, which
is stored mainly in the leaves
nicotine
inhibits voltage- dependent sodium channels in muscles
μ-conotoxin
is a powerful poison and
seems to benefit the plant by
protecting it from insects
working by attacking the
junctions between the insects’
nerve cells
Nicotine
inhibits N-type voltage- dependent calcium channels Because N-type voltage-dependent calcium channels are related to algesia, sensitivity to pain in the nervous system, ω-conotoxin has an analgesic effect
ω-conotoxin
- Cassava, sorghum, stone fruits, bamboo roots and almonds are especially important foods.
- Their function in plants is not really known but they are suspected to be anti-feedants.
Cyanogenic glycosides
antimalarial agent artemisinin from?
Artemisia annua
- Naturally-occurring chemical products of microorganisms that are deleterious or toxic in small doses to susceptible host.
- A special class of poison (“toxicum”) which differs from toxic substances such as cyanide or mercury in that they are of microbial origin.
Microbial toxins
- very potent neurotoxin produced by the
bacterium C. botulinum. - serious poisoning from food borne
botulinum toxin or colonization of wounds
by the toxin producing bacterium are
medical emergencies resulting in
widespread paralysis, usually starting in
the face and eye muscles
Botulinum toxin A
- anticancer agent blank isolated from plants include the from the yew tree
paclitaxel (Taxol)
is used for cosmetic reasons such as wrinkles and also for hyperhidrosis, gustatory sweating, alleviation of migraines, dystonia syndromes
Botox
FUNGAL TOXIN
- Hallucinogenic
Muscarin
Other sources of natural toxins are microscopic algae and plankton in oceans or sometimes in lakes that produce
chemical compounds that are toxic to humans but not to fish or shellfish that eat these toxin-producing organisms.
Aquatic biotoxins
FUNGAL TOXINS
- Irreversible damage to liver cells
Phalloidin
FUNGAL TOXINS
- Inhibits RNA polymerase II activity
Amanitin
FUNGAL TOXINS
- Aflatoxin
- liver damage
Aspergillus flavus
FUNGAL TOXIN
- Ergot
- Gangrene, convulsions, hallucinations (LCD)
Claviceps purpurea
