Fig. 2. Nested-PCR assay of frozen tissue from tilapia larvae and fry obtained from S.
agalactiae-positive farms (A), nested-PCR assay of paraffin-wax-embedded tissue
from tilapia larvae and fry obtained from S. agalactiae-positive farms (B), and internal
positive PCR control of tilapia β-actin gene (C). (A) Lanes 1 to 9: larvae and fry from S.
agalactiae-positive farms; lane 10: negative control; lane 11: S. agalactiae ST991 genomic
DNA positive control; lane 12: 100 bp DNA ladder. (B) Lanes 1 to 9: larvae and fry from S.
agalactiae-positive farms; lane 10: negative control; lane 11: S. agalactiae ST991 genomic
DNA positive control; lane 12: 100 bp DNA ladder. (C) Lane 1: 100 bp DNA ladder; lanes 2
to 6: frozen tissue from tilapia larvae and fry from S. agalactiae-positive farms; lanes 7 to
11: paraffin-wax-embedded larvae and fries from S. agalactiae-positive farms; lane 12:
negative control; lane 13: 10 ng of genomic tilapia DNA positive control.