2. Materials andmethods
2.1. Plant collection and extract preparation
Seaweeds P. gymnospora and S. cinereum were collected from the
Mandapam, Rameswaramcoastal area, Tamil Nadu, India. The collected
seaweeds were dried to remove salt content and unwanted debris. It
was then powdered for extraction. The extraction was done bymacerationmethod
using ethanol andwater. The extractswere kept in a shaker
for continuous agitation for 24 h and then filtered using filter paper. The
extracts were then filtered with filter paper. Filtered samples were
centrifuged to separate the fibrous matter from the supernatant. Thecrude extracts of both ethanol and aqueous were stored at 4 °C for
further use.
2.2. Collection and maintenance of experimental animals
Healthy fingerlings of Oreochromismossambicuswere collected from
a farm with no record of symptoms. They were transported in live
condition in 20 l containers containing freshwater with continuous
aeration. In the laboratory they were maintained in 1000 l fiberglass
tanks with continuous aeration in fresh water. The water temperature
was maintained between 28 and 30 °C.
2.3. Bacterial culture
Pseudomonas aeruginosa was purchased from MTCC and confirmed
by the biochemical reaction scheme provided by Fingold and Martin
(1982) and Bergy's Manual of Systemic Bacteriology. The culture was
maintained in the laboratory under aseptic condition. Bacterial culture
was grown on nutrient agar for use in pathogenicity experiments.