Affiliations: School of Life Sciences, Xiamen University, Xiamen
361005, China | State Key Laboratory of Marine Environmental Science,
Xiamen University, Xiamen 361005, China | Key Laboratory of Marine Ecology and Environmental
Science, ChineseAcademy of Sciences, Qingdao 266071, China
Abstract: The relationship between Alexandrium tamarense (Lebour) Balech, one
of red-tide alga, and two strains of marine bacteria, Bacillius megaterium
(S_7) and B. halmapulus (S_{10}) isolated
from Xiamen Western Sea, was investigated by evaluating the growth state of A.
tamarense and the variation of β-glucosidase activity in
co-culture system. The results showed the growth and multiplication of the alga
were related with the concentration, genus speciality of the bacteria, and
growth stage of the alga itself. The growth of A. tamarense was obviously
inhibited by S_7 and S_{10} at high
concentration. Either inhibition or promotion contributed much more clearly in
earlier than in later stage of the growth of the alga. Furthermore, there was a
roughly similar variation trend of the activity of extra-cellular enzyme,
β-glucosidase, in the water of the separately co-cultured bacteria
S_7 and S_{10} with the alga. The
β-glucosidase activity (β-GlcA) rapidly increased during the later
algal growth accompanying the increase of the lysis of the alga cells. The
obvious inhibition of A. tamarense by marine bacteria at high concentration and
evident increase of β-GlcA in co-colture system would help us in better
understanding the relationship between red-tide alga and bacteria, and also
enlightened us the possible use of bacteria in the bio-control of red-tide.
