SULFONAMIDE INHIBITION IN MONOCHRYSIS LUTHERP(1)

Area of Science:

• Marine biology
• Microbiology
• Biochemistry

Background:

• Sulfonamides are antimicrobial drugs with known effects on microbial growth.
• The marine alga Monochrysis lutheri is a key primary producer in marine ecosystems.
• Understanding the impact of xenobiotics on marine phytoplankton is crucial for environmental science.

Purpose of the Study:

• To investigate the effects of sulfonamides on the growth of Monochrysis lutheri.
• To determine the inhibitory concentrations and specific sulfonamides affecting algal growth.
• To explore the potential for competitive reversal of inhibition by other metabolites.

Main Methods:

• Monochrysis lutheri was cultured in a synthetic seawater medium for 14 days.
• Various concentrations of sulfonamides were added to assess growth inhibition.
• The effect of p-aminobenzoic acid and other metabolites on sulfonamide-induced inhibition was examined.

Main Results:

• Sulfonamides initially stimulated, then inhibited, Monochrysis lutheri growth at concentrations from 0.01 to 1.0 mg%.
• Sulfathiazole exhibited the most pronounced inhibition, followed by sulfamethazine, sulfapyridine, and sulfanilamide.
• Para-aminobenzoic acid competitively reversed the inhibitory effects of sulfonamides.

Conclusions:

• Sulfonamides can significantly impact the growth of marine algae like Monochrysis lutheri.
• Para-aminobenzoic acid plays a vital role in algal metabolism, potentially through a pathway targeted by sulfonamides.
• Antimetabolites like sulfonamides may have significant implications for marine ecosystems, warranting further investigation.