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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

Photosynthetic efficiency (Fv/Fm) (A), and photosynthetic capacity (rETR) exposed for 4 h (B) of A. tamarense treated with different concentrations of the bacterial culture. All error bars indicate the SE of the three biological replicates. *Represents a statistically significant difference of p < 0.05 when compared to the control; **represents a statistically significant difference of p < 0.01. DCMU concentration is 10 μM with incubation for 5 min. inset in (A) represents the Fv/Fm contents in algal cells after treated by DCMU; inset in (B) represents the NPQ contents in algal cells after treated by DCMU.
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Figure 6: Photosynthetic efficiency (Fv/Fm) (A), and photosynthetic capacity (rETR) exposed for 4 h (B) of A. tamarense treated with different concentrations of the bacterial culture. All error bars indicate the SE of the three biological replicates. *Represents a statistically significant difference of p < 0.05 when compared to the control; **represents a statistically significant difference of p < 0.01. DCMU concentration is 10 μM with incubation for 5 min. inset in (A) represents the Fv/Fm contents in algal cells after treated by DCMU; inset in (B) represents the NPQ contents in algal cells after treated by DCMU.

Mentions: Investigation of the photosynthetic efficiency in algal cells, Fv/Fm and rETR, revealed that, within 4 h of treatment, the Fv/Fm values were inhibited by the algicidal bacterial cultures, especially the 2.0 and 3.0% concentrations (Figure 6A), where the Fv/Fm value declined to extremely low levels (p < 0.01), only 6.8 and 7.3% of the control. In the 2.0 and 3.0% treatment groups, the photosynthetic efficiency was significantly lowered, and the Fv/Fm value was always hold down at a low level. The Fv/Fm value was continuously reduced in the 1.0% treatment group before 24 h, but increased within 48 h of treatment. However, there were no obvious differences of Fv/Fm value between the control and 0.5% treatment groups. We also studied the Fv/Fm value when adding DCMU, and the result showed that the Fv/Fm value was inhibited compared to the control (Figure 6A, inset), which implied that the algicidal bacteria had a similar function with DCMU, and could inhibit the photosynthetic efficiency of the algal cells.


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)

Photosynthetic efficiency (Fv/Fm) (A), and photosynthetic capacity (rETR) exposed for 4 h (B) of A. tamarense treated with different concentrations of the bacterial culture. All error bars indicate the SE of the three biological replicates. *Represents a statistically significant difference of p < 0.05 when compared to the control; **represents a statistically significant difference of p < 0.01. DCMU concentration is 10 μM with incubation for 5 min. inset in (A) represents the Fv/Fm contents in algal cells after treated by DCMU; inset in (B) represents the NPQ contents in algal cells after treated by DCMU.
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Related In: Results  -  Collection

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Figure 6: Photosynthetic efficiency (Fv/Fm) (A), and photosynthetic capacity (rETR) exposed for 4 h (B) of A. tamarense treated with different concentrations of the bacterial culture. All error bars indicate the SE of the three biological replicates. *Represents a statistically significant difference of p < 0.05 when compared to the control; **represents a statistically significant difference of p < 0.01. DCMU concentration is 10 μM with incubation for 5 min. inset in (A) represents the Fv/Fm contents in algal cells after treated by DCMU; inset in (B) represents the NPQ contents in algal cells after treated by DCMU.
Mentions: Investigation of the photosynthetic efficiency in algal cells, Fv/Fm and rETR, revealed that, within 4 h of treatment, the Fv/Fm values were inhibited by the algicidal bacterial cultures, especially the 2.0 and 3.0% concentrations (Figure 6A), where the Fv/Fm value declined to extremely low levels (p < 0.01), only 6.8 and 7.3% of the control. In the 2.0 and 3.0% treatment groups, the photosynthetic efficiency was significantly lowered, and the Fv/Fm value was always hold down at a low level. The Fv/Fm value was continuously reduced in the 1.0% treatment group before 24 h, but increased within 48 h of treatment. However, there were no obvious differences of Fv/Fm value between the control and 0.5% treatment groups. We also studied the Fv/Fm value when adding DCMU, and the result showed that the Fv/Fm value was inhibited compared to the control (Figure 6A, inset), which implied that the algicidal bacteria had a similar function with DCMU, and could inhibit the photosynthetic efficiency of the algal cells.

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