Algal Toxins of Salt River Reservoirs by Dr. Fiona Jordan Dr. - - PowerPoint PPT Presentation

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Algal Toxins of Salt River Reservoirs by Dr. Fiona Jordan Dr. - - PowerPoint PPT Presentation

Mar 03, 2023 109 likes •231 views

Algal Toxins of Salt River Reservoirs by Dr. Fiona Jordan Dr. David Walker Background Fish kills Fish kills Algal toxins in fish guts Algal toxins in fish guts Neurotoxins Neurotoxins Hepatotoxins Hepatotoxins

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SLIDE 1

Algal Toxins

  • f Salt River Reservoirs

by

  • Dr. Fiona Jordan
  • Dr. David Walker
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SLIDE 2

Background

  • Fish kills

Fish kills

  • Algal toxins in fish guts

Algal toxins in fish guts

  • Neurotoxins

Neurotoxins

  • Hepatotoxins

Hepatotoxins

  • Misleading aqueous samples

Misleading aqueous samples

  • Low

Low-

  • level toxins

level toxins

  • Short half

Short half-

  • life

life

  • Low

Low-

  • level algal toxin

level algal toxin-

  • producers

producers

  • Anabaena & Cylindrospermopsis

Anabaena & Cylindrospermopsis

Photo courtesy of Dave Rigo, AzG&F Dept.

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SLIDE 3

Project Goals

Improve toxin detection Protect public health Predict & possibly prevent future

fish kills.

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SLIDE 4

Aqueous Samples

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SLIDE 5

Known Toxin-Producers

Microcystin-LR

Cylindrospermopsis Microcystis Anabaena

Anatoxin-a Cylindrospermopsin

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SLIDE 6

Genetic Characterization

Dendrogram of cyanobacterial 16 S genes (generated by RFLP). Scale bar = similarity coefficients. Numbers 1–4 = clades. Symbols: neurotoxic; non-toxic; hepatotoxic; toxicity not determined; type of toxicity unknown.

Lyra et al. (2001)

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SLIDE 7

Dendrogram of cyanobacterial genomic fingerprints (generated by REP- and ERIC-PCR). Scale = similarity coefficients. Numbers 1–4 = groups. Symbols: neurotoxic; non-toxic; hepatotoxic; toxicity not determined; type of toxicity unknown.

Lyra et al. (2001)

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SLIDE 8

Toxin Production

Environmental triggers??

Salinity, pH, light, temperature, DOC Single isolate vs mixed culture

Characterize toxins

HPLC & LCMS

–structure and quantity

LD 50???

  • Characterize toxin producers

Genes???

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SLIDE 9

Objectives

I.

Isolate suspect algal species

I.

Obtain axenic cultures

II.

Factors influencing toxin production

I.

Biotic and abiotic

  • II. Biological assays
  • III. Characterize toxins & isolates
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SLIDE 10
  • Isolate individual species
  • Axenic
  • bacterial-free
  • uni-algal
  • Pure cultures
  • solid or liquid media
  • Genetic characterization

Axenic Cultures

http://honeybee.helsinki.fi/mmkem/MIKRO/PROJEKTI/syano/pullot.jpg

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SLIDE 11

Fish Bioassays

Expose fish to Individual algae Environmental conditions = algae Algal supernatant Mixed population Determine lethality/toxicity Identify toxins Liquid and tissue Type and quantity