Cyanobacteria Flashcards
What conditions favour algal blooms?
Increased temp, light, high nutrient concentrations, still waters
What are cyanobacteria?
photosynthetic prokaryotes, inhabit diverse habitats
What are the routes of exposure for cyanotoxins?
skin contact, inhalation, ingestion, haemodialysis,
What are the four types of cyanotoxins talked about in class?
Anatoxin-a, anatoxin-a(s), Microcystin, cylindrospermopsin
What are the examples of hepatotoxins talked about in class?
Microcystins, and cylindrospermopsin
What are the producing genera of microcytsins?
anabaena, microcystis, plankothrix and pseudoanabaena
What is the structure of the microcystins?
cyclic peptides with several amino acids
What is the MOA of microcystins?
inhibition of protein phosphatase 1 and 2, disrupts cell signalling and potentially leads to cell death
What is one property of microcystins that make it concerning?
Can bioaccumulate in marine organisms
How do we diagnose microcystin poisoning?
Protein phosphatase inhibition assay
What are the early and late symptoms of animals of microcystin poisoning?
Early: shallow breathing, diarrhea, vomiting, increased bilirubin and coagulation times, alanine transaminase, alkaline phosphatase and creatine kinase activity, hypoglycemia, hyperphosphatemia and hyperkalemia
Late: icterus, hemorrage, hepatic necrosis, renal tubular necrosis, increased total bilirubin concentration
What are the symptoms in humans after having microcystin poisoning?
nausea, vomiting, headache, muscle weakness, increased bilirubin, and aspartate aminotransferase
What are the species that produce cylindrospermopsin?
cylindrospermopsis raciborskii, aphanizomenon ovalisporum and umezakia natans
What is the structure of cylindrospermopsin?
Alkaloid with tricyclic ring structure
What is the LD 50 of cylindrospermopsin?
5mg/kg
Whats the MOA of cylindospermopsin?
inhibiting protein synthesis through DNA fragmentation-possible p450 actication- damages hepatocytes, impaired liver and kidney functions
What are the effects of cylindrospermopsin poisoning in humans?
vomiting, headache, fever, bloody diarrhea, hepatomegaly and renal damage
What are the acute symptoms for animals of cylindrospermopsin poisoning?
liver damage, lung damage (if inhaled), renal tubular necrosis, ulceration in GI tract, atrophy of lymphoid tissues in spleen and thymus, hemorrhages in the heart
What are some chronic symptoms in animals for cylindrospermopsin poisoning>
genotoxicity, mild liver and kidney damage, potentially reproductive damage
Where is cylindrospermopsin most prevalent in the world?
Asia
What are the neurotoxins described in class?
Anatoxin-a, homoanatoxin and anatoxin-a(s)
What are the genera that produce anatoxin-a
Anabaena, aphanizomenon, microcystis, oscillatoria
What are the genera that produce anatoxin-a(s)
anabaena, oscillatoria
What is the structure of anatoxins?
structurally similar alkaloids
What is the MOA of anatoxin-a and homoanatoxin?
nicotinic agonists-mimic acetylcholine, constant flow of sodium ions, and repetitive action potentials
What is the MOA of anatoxin-a(s)
irreversibly binds acetylcholinesterase
What are the early effects of anatoxin poisoning in animals?
muscle fasciculations, tremors, rigidity, and eventual paralysis/resp. failure (death)
What is the LD50 for anatoxin in humans?
250ug/kg
What are the two dermatotoxins discussed in class?
lyngbyatoxins and aplysiatoxins
What species produce lyngbyatoxins and where is it found?
Lyngbya majuscule and found in tropical and subtropical regions
What is the structure of lyngbyatoxins?
polycyclic diterpenes
What is the MOA of lyngbyatoxins?
contains functional groups that allow it to interact with biological membranes and other cellular structures
What are the species that produce aplysiatoxins?
L. majuscula, schizothrix calcicola and phormdium species
What is the structure of aplysiatoxins and what is special about this toxin?
polycyclic diterpenes, ability to undergo structural modifications
What is the MOA of aplysiatoxins?
activation of protein kinase C which leads to abnormal cell signalling, and cell proliferation
What are the acceptable levels of microcystins in drinking water and recreational water?
1ug/L in drinking water, 10ug/L in recreational
What is the most common and most toxic microcystin congener?
MC-LR-leucine arginine amino acid present
Why are lakes prone to algal blooms?
Urea fertilizer and increasing warmth
What was special about the dugouts in Saskatchewan?
MC levels were not detectable often
Where is one of the habitats with the most concentrated MC levels and what is a theory behind that?
Wetlands, high levels of TN and TP but low ratio of the two
What are natural MC degradation strategies?
sunlight, bacteria, fungi, and plants
