Fine-scale spatial variability in anatoxin-a and homoanatoxin-a concentrations in benthic cyanobacterial mats: implication for monitoring and management.
OBJECTIVE
The purpose of this study was to determine the variability in anatoxin-a (ATX) and homoanatoxin-a (HTX) concentrations in benthic cyanobacterial mats within sampling sites and to assess the applicability of using a PCR-based approach to determine ATX- and HTX-production potential.


RESULTS
ATX and HTX variability was investigated by collecting 15 samples from 10 × 10 m grids in seven rivers. ATX and HTX concentrations were determined using liquid chromatography-mass spectrometry (LC-MS). Samples from two sites contained no ATX or HTX and at one site ATX and HTX were detected in all samples. At four sites, both toxic and nontoxic samples co-occurred and these samples were sometimes spaced less than 1 m apart. PCR amplification of a region of a polyketide synthase (ks2, putatively involved in the biosynthetic pathway of ATX and HTX) successfully distinguished ATX-and-HTX- and non-ATX-and-HTX-producing cultured Phormidium strains. Results from environmental samples were more variable, and the results were in congruence with the LC-MS data in only 58% of samples.


CONCLUSIONS
Fine-scale spatial variability in ATX and HTX concentrations occurs among benthic cyanobacterial mats.


CONCLUSIONS
Multiple benthic cyanobacterial mat samples must be collected at a sampling site to provide an accurate assessment of ATX and HTX concentrations at that location. The PCR-based technique offers the potential to be a useful early warning technique.
Wood
S A
SA
Cawthron Institute, Nelson, New Zealand. susie.wood@cawthron.org.nz
Heath
M W
MW
Kuhajek
J
J
Ryan
K G
KG
D001427:Bacterial Toxins / Q000032:analysis*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000032:analysis*; D002853:Chromatography, Liquid; D000458:Cyanobacteria / Q000737:chemistry* / Q000235:genetics; D000087522:Cyanobacteria Toxins; D004784:Environmental Monitoring / Q000379:methods*; D013058:Mass Spectrometry; D009520:New Zealand; D048630:Polyketide Synthases / Q000235:genetics; D045483:Rivers / Q000382:microbiology; D014326:Tropanes / Q000032:analysis*; D014871:Water Microbiology
D001427:Bacterial Toxins; D019086:Bridged Bicyclo Compounds, Heterocyclic; D000087522:Cyanobacteria Toxins; D014326:Tropanes; C524097:homoanatoxin-a; D048630:Polyketide Synthases; C509783:anatoxin a