Anilines: selective toxicity to blue-green algae

Area of Science:

• Environmental Toxicology
• Microbiology
• Phycology

Background:

• Aniline and p-toluidine are potential environmental toxicants.
• Blue-green algae, also known as cyanobacteria, play crucial roles in aquatic ecosystems.
• Assessing the sensitivity of various microorganisms to these toxicants is important for environmental risk assessment.

Purpose of the Study:

• To determine the sensitivity of the blue-green alga Agmenellum quadruplicatum to aniline and p-toluidine.
• To compare the sensitivity of different algal and bacterial species to p-toluidine.

Main Methods:

• Algal lawn assay was used to assess the growth inhibition of Agmenellum quadruplicatum.
• Sensitivity of seven other blue-green algal species to p-toluidine was tested.
• Comparative assays were conducted with a green alga, a diatom, and two bacterial species.

Main Results:

• Agmenellum quadruplicatum (strain PR6) showed high sensitivity, with growth inhibited by 1 microgram of p-toluidine per disk.
• Other blue-green algae exhibited varying sensitivities, ranging from 1 to 100 micrograms of p-toluidine.
• Green algae, diatoms, and bacteria required significantly higher concentrations (0.5 mg or more) of p-toluidine for growth inhibition.
• p-Toluidine did not immediately affect photosynthesis or respiration in A. quadruplicatum, but arrested growth and reduced viability.

Conclusions:

• Blue-green algae, particularly Agmenellum quadruplicatum, are highly susceptible to p-toluidine and aniline.
• Cyanobacteria represent a sensitive indicator group for detecting environmental contamination by these toxicants.
• The differential sensitivity among microbial groups suggests specific mechanisms of toxicity and potential ecological impacts.