Role of secondary metabolites as defense chemicals against ice-ice disease bacteria in biofouler at carrageenophyte farms

Abstract

Carrageenophyte farming is an expanding economical activity in North Borneo Island, Malaysia. During routine monitoring of "ice-ice" disease and epiphyte outbreak at commercial farms, it was apparent that culture lines were heavily (60-80%) infested with biofoulers, particularly Acanthophora spp. and Laurencia majuscula. However, only L. majuscula showed dominance and flourished even during "ice-ice" disease outbreak. Presence of chemical defense against seaweed pathogens was investigated in two populations of L. majuscula collected from three major carrageenophyte farms in two districts; (A) Lohok Butun, Selakan Island, and Bum-Bum Island, in Semporna district, and (B) Telutuh, Carrington Reef, and Balambangan Island, in Kudat district. The first population contained elatol (1), and iso-obtusol (2), and, second population contained (Z)-10,15-dibromo-9-hydroxy-chamigra-1,3(15),7(14)-triene (3) and (E)-10-15-dibromo-9-hydroxy-chamigra-1,3(15),7(14)-triene (4), as their antibacterial metabolites. All four metabolites showed highly selective inhibition against "ice-ice" disease bacteria compared to human pathogens at 30µg disk −1 . In addition, seasonal variation of these compounds at two representative farms (Selakan Island [P-1] and Balambangan Island [P-2]) revealed a 120-170% increase in concentration during "ice-ice" disease outbreak. Microscopy of fresh specimens showed the presence of corps en cerise, which is the synthesis and storage site of halogenated metabolites at superficial cortical cells, branch tips, and trichoblasts. This suggests the importance of these metabolites as defense chemicals against "ice-ice" disease bacteria in L. majuscula that grows on seaweed culture lines.

Chemical interactions between marine macroalgae and bacteria

“…Research on the induced defense mechanisms against microbial pathogens or epibiosis is still limited. Recently, Vairappan et al (2010) were the first to demonstrate the highly selective antibiotic activity of extracts from the epiphytic macroalga Laurencia majuscula against 6 algal pathogenic bacteria. Table 5.…”

The Laurencia Paradox: An Endless Source of Chemodiversity

“…Isoobtusol (49), isoobtusol acetate (50), and obtusol (175) are also found as common constituents in several Laurencia species and their antibacterial and antifungal activities have been reported in a number of articles [50,135,155,384,876]. Evaluation of the related sesquiterpenes allolaurinterol (151) [166,248,259,260,855,877], allolaurinterol acetate (152) [152,260], debromoallolaurinterol (149) [248], debromoallolaurinterol acetate (150) [152], isolaurinterol (161) [62,201,267,279,877], laurinterol (231) [62,105,137,309,877], debromolaurinterol (226) [309,855,878], and isodebromolaurinterol (229) [201,267,279] has been performed in several, albeit fragmented, studies, which do not allow direct comparison of the structural features with the reported antimicrobial activities.…”

“…Furthermore, a significant number of Laurencia sesquiterpenes including (-)-(10R)-bromo-α-chamigrene (1) [81], laurecomin C (2) [84], 7 [84], laurokamin C (12) [79], 10-bromo-9-hydroxy-α-chamigrene (14) [81], dendroidiol (34) [146], laurecomin B (37) [84], 10-bromo-β-chamigren-8-ol (41) [152,275], 44 [62,155] 10-hydroxy-kahukuene B (633) [74], aplysiadiol (638) [187], and (E)-phytol (641) [342] have been evaluated for their antibacterial and antifungal properties.…”

Dual effect of macroalgal extracts on growth of bacteria in Western Baltic Sea

“…It is accepted that chemical defences are elaborated to a greater extent and are more important in tropical than temperate or cold areas as in the German coast (see Pereira & da Gama 2008). Unfortunately, with the exception of one study using causative agents of the macroalgal iceice disease (by Vairappan et al 2010) and P. elyakovii (by Thabard et al 2011), bioactivity tests of algal extracts or compounds against other known bacterial pathogens of macroalgae were rarely performed.…”