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The death mechanism of the harmful algal bloom species Alexandrium tamarense induced by algicidal bacterium Deinococcus sp. Y35.

Li Y, Zhu H, Lei X, Zhang H, Cai G, Chen Z, Fu L, Xu H, Zheng T - Front Microbiol (2015)

Bottom Line: Harmful algal blooms (HABs) cause a variety of deleterious effects on aquatic ecosystems, especially the toxic dinoflagellate Alexandrium tamarense, which poses a serious threat to marine economic and human health based on releasing paralytic shellfish poison into the environment.Photosynthetic pigments including chlorophyll a and carotenoid decreased along with the photosynthetic efficiency being significantly inhibited.More than, the destruction of cell nuclear structure and inhibition of proliferating cell nuclear antigen (PCNA) related gene expression were confirmed.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Marine Environmental Science and Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University Xiamen, China ; College of Life Sciences, Henan Normal University Xinxiang, China.

ABSTRACT
Harmful algal blooms (HABs) cause a variety of deleterious effects on aquatic ecosystems, especially the toxic dinoflagellate Alexandrium tamarense, which poses a serious threat to marine economic and human health based on releasing paralytic shellfish poison into the environment. The algicidal bacterium Deinococcus sp. Y35 which can induce growth inhibition on A. tamarense was used to investigate the functional mechanism. The growth status, reactive oxygen species (ROS) content, photosynthetic system and the nuclear system of algal cells were determined under algicidal activity. A culture of strain Y35 not only induced overproduction of ROS in algal cells within only 0.5 h of treatment, also decrease the total protein content as well as the response of the antioxidant enzyme. Meanwhile, lipid peroxidation was induced and cell membrane integrity was lost. Photosynthetic pigments including chlorophyll a and carotenoid decreased along with the photosynthetic efficiency being significantly inhibited. At the same time, photosynthesis-related gene expression showed down-regulation. More than, the destruction of cell nuclear structure and inhibition of proliferating cell nuclear antigen (PCNA) related gene expression were confirmed. The potential functional mechanism of the algicidal bacterium on A. tamarense was investigated and provided a novel viewpoint which could be used in HABs control.

No MeSH data available.


Related in: MedlinePlus

Inhibitory effects of the bacterial culture on chlorophyll a (A) and carotenoid (B) contents in A. tamarense, and the TEM morphology of a control (C) and damaged chloroplast (D). All error bars indicate SE of the three replicates. *Represents a statistically significant difference of p < 0.05 when compared to the control, **represents a statistically significant difference of p < 0.01. Bars (C,D) 0.5 μm.
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Figure 5: Inhibitory effects of the bacterial culture on chlorophyll a (A) and carotenoid (B) contents in A. tamarense, and the TEM morphology of a control (C) and damaged chloroplast (D). All error bars indicate SE of the three replicates. *Represents a statistically significant difference of p < 0.05 when compared to the control, **represents a statistically significant difference of p < 0.01. Bars (C,D) 0.5 μm.

Mentions: The cellular pigments, Chl a and carotenoid contents in the algal cells were significantly decreased under the effect at concentrations of 1.0, 2.0, and 3.0% of algicidal culture (Figure 5). The Chl a contents decreased (p < 0.01) from 4 h of treatment to 48 h (Figure 5A), and the maximum inhibitory effect of the bacterial culture was achieved within 48 h exposure. The Chl a contents were approximately 14.6, 13.8, and 34.2% that of the control after exposure to the 1.0, 2.0, and 3.0% concentrations of bacterial culture. However, the 0.5% concentration did not show any obvious effect on Chl a content compared to the control. The carotenoid contents in the treatment groups showed similar trends with Chl a content, and were greatly decreased during the algicidal procedure (Figure 5B). After 48 h of treatment, the carotenoid contents were significantly (p < 0.01) decreased under the effect of the 1.0, 2.0, and 3.0% concentrations of bacterial culture, and were approximately 14.3, 14.0, and 32.0% of the control. Under the algicidal activity of the bacterial culture, the structure and morphology of the chloroplasts changed obviously compared to the control (Figures 5C,D). In the control, the chloroplast structure was intact and clear, with tightly and evenly distributed thylakoids and tubular cristae. However, the chloroplast membrane was destroyed, and the internal structure became sparse and fuzzy, when the chloroplast structure was damaged under the algicidal effect (Figure 5D).


The death mechanism of the harmful algal bloom species Alexandrium tamarense induced by algicidal bacterium Deinococcus sp. Y35.

Li Y, Zhu H, Lei X, Zhang H, Cai G, Chen Z, Fu L, Xu H, Zheng T - Front Microbiol (2015)

Inhibitory effects of the bacterial culture on chlorophyll a (A) and carotenoid (B) contents in A. tamarense, and the TEM morphology of a control (C) and damaged chloroplast (D). All error bars indicate SE of the three replicates. *Represents a statistically significant difference of p < 0.05 when compared to the control, **represents a statistically significant difference of p < 0.01. Bars (C,D) 0.5 μm.
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Figure 5: Inhibitory effects of the bacterial culture on chlorophyll a (A) and carotenoid (B) contents in A. tamarense, and the TEM morphology of a control (C) and damaged chloroplast (D). All error bars indicate SE of the three replicates. *Represents a statistically significant difference of p < 0.05 when compared to the control, **represents a statistically significant difference of p < 0.01. Bars (C,D) 0.5 μm.
Mentions: The cellular pigments, Chl a and carotenoid contents in the algal cells were significantly decreased under the effect at concentrations of 1.0, 2.0, and 3.0% of algicidal culture (Figure 5). The Chl a contents decreased (p < 0.01) from 4 h of treatment to 48 h (Figure 5A), and the maximum inhibitory effect of the bacterial culture was achieved within 48 h exposure. The Chl a contents were approximately 14.6, 13.8, and 34.2% that of the control after exposure to the 1.0, 2.0, and 3.0% concentrations of bacterial culture. However, the 0.5% concentration did not show any obvious effect on Chl a content compared to the control. The carotenoid contents in the treatment groups showed similar trends with Chl a content, and were greatly decreased during the algicidal procedure (Figure 5B). After 48 h of treatment, the carotenoid contents were significantly (p < 0.01) decreased under the effect of the 1.0, 2.0, and 3.0% concentrations of bacterial culture, and were approximately 14.3, 14.0, and 32.0% of the control. Under the algicidal activity of the bacterial culture, the structure and morphology of the chloroplasts changed obviously compared to the control (Figures 5C,D). In the control, the chloroplast structure was intact and clear, with tightly and evenly distributed thylakoids and tubular cristae. However, the chloroplast membrane was destroyed, and the internal structure became sparse and fuzzy, when the chloroplast structure was damaged under the algicidal effect (Figure 5D).

Bottom Line: Harmful algal blooms (HABs) cause a variety of deleterious effects on aquatic ecosystems, especially the toxic dinoflagellate Alexandrium tamarense, which poses a serious threat to marine economic and human health based on releasing paralytic shellfish poison into the environment.Photosynthetic pigments including chlorophyll a and carotenoid decreased along with the photosynthetic efficiency being significantly inhibited.More than, the destruction of cell nuclear structure and inhibition of proliferating cell nuclear antigen (PCNA) related gene expression were confirmed.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Marine Environmental Science and Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University Xiamen, China ; College of Life Sciences, Henan Normal University Xinxiang, China.

ABSTRACT
Harmful algal blooms (HABs) cause a variety of deleterious effects on aquatic ecosystems, especially the toxic dinoflagellate Alexandrium tamarense, which poses a serious threat to marine economic and human health based on releasing paralytic shellfish poison into the environment. The algicidal bacterium Deinococcus sp. Y35 which can induce growth inhibition on A. tamarense was used to investigate the functional mechanism. The growth status, reactive oxygen species (ROS) content, photosynthetic system and the nuclear system of algal cells were determined under algicidal activity. A culture of strain Y35 not only induced overproduction of ROS in algal cells within only 0.5 h of treatment, also decrease the total protein content as well as the response of the antioxidant enzyme. Meanwhile, lipid peroxidation was induced and cell membrane integrity was lost. Photosynthetic pigments including chlorophyll a and carotenoid decreased along with the photosynthetic efficiency being significantly inhibited. At the same time, photosynthesis-related gene expression showed down-regulation. More than, the destruction of cell nuclear structure and inhibition of proliferating cell nuclear antigen (PCNA) related gene expression were confirmed. The potential functional mechanism of the algicidal bacterium on A. tamarense was investigated and provided a novel viewpoint which could be used in HABs control.

No MeSH data available.


Related in: MedlinePlus