Producing mechanism of an algicidal compound against red tide phytoplankton in a marine bacterium γ-proteobacterium

Abstract

Strain MS-02-063, gamma-proteobacterium, isolated from a coast area of Nagasaki, Japan, produced a red pigment which belongs to prodigiosin members. This pigment, PG-L-1, showed potent algicidal activity against various red tide phytoplanktons in a concentration-dependent manner. An understanding of a mechanism of PG-L-1 production by this marine bacterium may yield important new insights and strategies for preventing blooms of harmful flagellate algae in natural marine environments. Therefore, we analyzed the mechanisms of PG-L-1 production. In our previous study, the pigment production by this marine bacterium was completely inhibited at 1.56 microg/ml of erythromycin or 3.13 microg/ml of chloramphenicol, while minimal inhibitory concentrations for cell growth of erythromycin and chloramphenicol against this bacterium were >100 and 25 microg/ml, respectively. It is interesting to note that the ability of the pigment production in erythromycin-treated bacterium recovered by an addition of homoserine lactone. In fact, the pigment production was inhibited by beta-cyclodextrin that inhibits autoinducer activities by a complex with N-acyl homoserine lactones. N-acyl homoserine lactones with autoinducer activities are ubiquitous bacterial signaling molecules that regulate gene expression in a cell density dependent process known as quorum sensing. Therefore, it was suggested that PG-L-1 produced by strain MS-02-063 is controlled by the homoserine lactone quorum sensing. It is speculated that this quorum sensing is involved in the production of algicidal agents of other marine bacteria. This bacterium and other algicidal bacteria might be concerned in regulating the blooms of harmful flagellate algae through the quorum sensing system.

Microbial interactions associated with biofilms attached to Trichodesmium spp. and detrital particles in the ocean

“…AHLs have been demonstrated to stimulate the settlement of zoospores of the macroalgae Ulva intestinalis (Tait et al, 2005) and Enteromorpha (Joint et al, 2002). AHL-QS has also been implicated in large-scale bioluminescence events coincident with algal blooms , in the degradation of organic carbon Ziervogel & Arnosti, 2008) and in the regulation of algal blooms (Nakashima et al, 2006).…”

“…prodigiosin, Nakashima et al, 2006), two processes which may directly impact the fate of photosynthetically derived carbon in the ocean. QS has been implicated in the degradation of marine snow in the environment , although mechanistic…”

“…QS by algalassociated bacteria has been implicated in the bloom-dynamics of other marine algae (Nakashima et al, 2006) and lacustrine cyanobacteria (Braun & Bachofen, 2004), although not yet in association with Trichodesmium or any other marine cyanobacterium.…”

Advances in the Bio-Active Products from Marine Bacteria—A Review

“…基于"以菌治藻"理念，近几年关于海洋细菌在 赤潮防治中的作用已有大量文献报道。细菌可通过直 接或间接方式杀藻 [37] 。国外，Lee 等 [38] 从来自日本有 明海的假交替单胞菌 A28 培养液中纯化获得能溶解 …”

Production, Extraction and Characterization of Red Pigment Produced by Serratia rubidaea JCM 1240T isolated from Soil

“…According to a recent report, prodigiosin or its analogues have been considered effective biological control agents against harmful algae (Jeong et al, 2005;Nakashima et al, 2006) have been considered cell growth regulators (Haddix et al, 2008) and can be used as a natural dye (Alihosseini, et al, 2008). The present investigation focuses on i) Identification of red pigment producing bacteria by 16 S rRNA Sequencing ii) Test the red pigment produced by the red bacteria for prodigiosin by presumptive color test and adsorption spectra, and iii) confirmation red pigment as prodigiosin by IR, NMR and Mass spectrophotometer.…”