The Experts below are selected from a list of 237 Experts worldwide ranked by ideXlab platform
Haimin Chen - One of the best experts on this subject based on the ideXlab platform.
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Bacteriophage therapy on the Conchocelis of Pyropia haitanensis (Rhodophyta) infected by Vibrio mediterranei 117-T6
Aquaculture, 2021Co-Authors: Junkai Zhu, Qiqin Liu, Rui Yang, Haimin ChenAbstract:Abstract Yellow spot disease (YSD) is a destructive disease that usually occurs at the Conchocelis nursery stage of commercially cultivated Pyropia species. Vibrio mediterranei 117-T6 has been identified as the pathogenic bacteria causing YSD. To develop a biological control program for YSD, we investigated the effects of bacteriophage vB_VmeM-Yong XC31 (phage XC31) on the density of the pathogenic bacteria, the physiological and biochemical parameters of the free-living Conchocelis (FLC) and the shell-borne Conchocelis (SBC) of Pyropia haitanensis infected by V. mediterranei 117-T6. The highest survival rate (83%) of infected FLC was obtained when the density of V. mediterranei 117-T6 was 108 CFU/mL and the multiplicity of infection (MOI) of phage XC31 was 1. Under these conditions, phage XC31 could kill the pathogens and significantly decrease the Vibrio density in the infection system (P
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Changes in phycospheric and environmental microbes associated with an outbreak of yellow spot disease on Pyropia yezoensis
Aquaculture, 2020Co-Authors: Qiqin Liu, Yajun Zhi, Zhiming Ren, Haimin Chen, Rui YangAbstract:Abstract The composition and diversity of phycospheric microbes are critical to the health of algae. Pyropia yezoensis is a popular edible seaweed in Asia and yellow spot disease (YSD) is a serious disease during its Conchocelis sporeling culture period. We studied the changes of the bacterial flora in the phycosphere and the surrounding seawater of P. yezoensis Conchocelis during a YSD outbreak and treatment. Four types of algal conditions were studied 1) healthy (no previous YSD); 2) YSD; 3) YSD being treated with ClO2 and 4) recovery (14 d after treatment). In the YSD samples, the microbial diversity was significantly decreased. The abundance of bacteria that were reported having algal dissolving and degrading functions (Kangiella, Alteromonas, Kordiimona, Tenacibaculum and Winogradskyella) was significantly increased, and some beneficial bacteria (Ruegeria and Bdellovibrio) had significantly decreased populations (P
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Isolation and identification of Vibrio mediterranei 117-T6 as a pathogen associated with yellow spot disease of Pyropia (Bangiales, Rhodophyta)
Aquaculture, 2020Co-Authors: Rui Yang, Qiqin Liu, Qijun Luo, Zhen Tao, Juanjuan Chen, Haimin ChenAbstract:Abstract Pyropia is an important cultivated seaweed in Northeast Asia. Yellow spot disease (YSD) commonly occurs in Conchocelis sporeling cultures of Pyropia and causes huge economic losses. In this study, the isolated strain 117-T6 was identified as a pathogenic bacterium of YSD in Pyropia by Koch's postulates. Based on the morphological, physiological, and biochemical characteristics and multi-locus analysis of house-keeping gene sequences, this gram-negative bacterium was named as Vibrio mediterranei 117-T6. V. mediterranei 117-T6, including its intracellular and the extracellular extracts, caused both free-living Conchocelis (FLC) and shell-borne Conchocelis (SBC) to exhibit YSD symptoms within 12 days, indicating that the bacteria might attack Pyropia by secreting certain compounds that can be transported into algal cells, breaking down their structure and leading to death. During the infection, four stages were observed. 1) Prophase: a large number of pathogenic bacteria gathered around the algae. The Conchocelis was in healthy condition at that time. 2) Early stage: organelle edges of Pyropia were blurred, mitochondria and chloroplasts became fluffy and unraveled, autophagosomes appeared. 3) Middle stage: cellular structures and contents of the algae kept being lost and degraded, cell walls became thin. 4) Late stage: the Conchocelis bleached completely, and as the cell wall disintegrated gradually, the bacteria took over the remains of Pyropia. Finally, the whole algal cell disappeared, which may be the reason for shell bleaching. Our results show that YSD caused by V. mediterranei 117-T6 is a severe disease of algal disintegration caused by bacterial secretion, with a short onset and severe symptoms.
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Different Responses to Heat Shock Stress Revealed Heteromorphic Adaptation Strategy of Pyropia
2016Co-Authors: Haitanensis Rhodophyta, Haimin Chen, Rui Yang, Qijun Luo, Zhenggang Zhu, Zhujun Zhu, Feijian Qian, Xiaojun YanAbstract:Pyropia has a unique heteromorphic life cycle with alternation stages between thallus and Conchocelis, which lives at different water temperatures in different seasons. To better understand the different adaptation strategies for temperature stress, we tried to observe comparative biochemical changes of Pyropia haitanensis based on a short term heat shock model. The results showed that: (1) At normal temperature, free-living Conchocelis contains significantly higher levels of H2O2, fatty acid-derived volatiles, the copy number of Phrboh and Phhsp70 genes,the activities of NADPH oxidase and floridoside than those in thallus. The released H2O2 and NADPH oxidase activity of Conchocelis were more than 7 times higher than those of thallus. The copy number of Phrboh in Conchocelis was 32 times that in thallus. (2) After experiencing heat shock at 35uC for 30 min, the H2O2 contents, the mRNA levels of Phrboh and Phhsp70, NADPH oxidase activity and the floridoside content in thallus were all significantly increased. The mRNA levels of Phrboh increased 5.78 times in 5 min, NADPH oxidase activity increased 8.45 times in 20 min. (3) Whereas, in Conchocelis, the changes in fatty acids and their down-stream volatiles predominated, significantly increasing levels of saturated fatty acids and decreasing levels of polyunsaturated fatty acids occurred, and the 8-carbon volatiles were accumulated. However, the changes in H2O2 content and expression of oxidant-related genes and enzymatic activity were not obvious. Overall, these results indicate that Conchocelis maintains a high level of active protective apparatus to endure its survival at high temperature, while thallu
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Different responses to heat shock stress revealed heteromorphic adaptation strategy of Pyropia haitanensis (Bangiales, Rhodophyta).
PloS one, 2014Co-Authors: Qijun Luo, Haimin Chen, Rui Yang, Zhenggang Zhu, Zhujun Zhu, Feijian Qian, Xiaojun YanAbstract:Pyropia has a unique heteromorphic life cycle with alternation stages between thallus and Conchocelis, which lives at different water temperatures in different seasons. To better understand the different adaptation strategies for temperature stress, we tried to observe comparative biochemical changes of Pyropia haitanensis based on a short term heat shock model. The results showed that: (1) At normal temperature, free-living Conchocelis contains significantly higher levels of H2O2, fatty acid-derived volatiles, the copy number of Phrboh and Phhsp70 genes,the activities of NADPH oxidase and floridoside than those in thallus. The released H2O2 and NADPH oxidase activity of Conchocelis were more than 7 times higher than those of thallus. The copy number of Phrboh in Conchocelis was 32 times that in thallus. (2) After experiencing heat shock at 35°C for 30 min, the H2O2 contents, the mRNA levels of Phrboh and Phhsp70, NADPH oxidase activity and the floridoside content in thallus were all significantly increased. The mRNA levels of Phrboh increased 5.78 times in 5 min, NADPH oxidase activity increased 8.45 times in 20 min. (3) Whereas, in Conchocelis, the changes in fatty acids and their down-stream volatiles predominated, significantly increasing levels of saturated fatty acids and decreasing levels of polyunsaturated fatty acids occurred, and the 8-carbon volatiles were accumulated. However, the changes in H2O2 content and expression of oxidant-related genes and enzymatic activity were not obvious. Overall, these results indicate that Conchocelis maintains a high level of active protective apparatus to endure its survival at high temperature, while thallus exhibit typical stress responses to heat shock. It is concluded that Pyropia haitanensis has evolved a delicate strategy for temperature adaptation for its heteromorphic life cycle.
Rui Yang - One of the best experts on this subject based on the ideXlab platform.
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Bacteriophage therapy on the Conchocelis of Pyropia haitanensis (Rhodophyta) infected by Vibrio mediterranei 117-T6
Aquaculture, 2021Co-Authors: Junkai Zhu, Qiqin Liu, Rui Yang, Haimin ChenAbstract:Abstract Yellow spot disease (YSD) is a destructive disease that usually occurs at the Conchocelis nursery stage of commercially cultivated Pyropia species. Vibrio mediterranei 117-T6 has been identified as the pathogenic bacteria causing YSD. To develop a biological control program for YSD, we investigated the effects of bacteriophage vB_VmeM-Yong XC31 (phage XC31) on the density of the pathogenic bacteria, the physiological and biochemical parameters of the free-living Conchocelis (FLC) and the shell-borne Conchocelis (SBC) of Pyropia haitanensis infected by V. mediterranei 117-T6. The highest survival rate (83%) of infected FLC was obtained when the density of V. mediterranei 117-T6 was 108 CFU/mL and the multiplicity of infection (MOI) of phage XC31 was 1. Under these conditions, phage XC31 could kill the pathogens and significantly decrease the Vibrio density in the infection system (P
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Changes in phycospheric and environmental microbes associated with an outbreak of yellow spot disease on Pyropia yezoensis
Aquaculture, 2020Co-Authors: Qiqin Liu, Yajun Zhi, Zhiming Ren, Haimin Chen, Rui YangAbstract:Abstract The composition and diversity of phycospheric microbes are critical to the health of algae. Pyropia yezoensis is a popular edible seaweed in Asia and yellow spot disease (YSD) is a serious disease during its Conchocelis sporeling culture period. We studied the changes of the bacterial flora in the phycosphere and the surrounding seawater of P. yezoensis Conchocelis during a YSD outbreak and treatment. Four types of algal conditions were studied 1) healthy (no previous YSD); 2) YSD; 3) YSD being treated with ClO2 and 4) recovery (14 d after treatment). In the YSD samples, the microbial diversity was significantly decreased. The abundance of bacteria that were reported having algal dissolving and degrading functions (Kangiella, Alteromonas, Kordiimona, Tenacibaculum and Winogradskyella) was significantly increased, and some beneficial bacteria (Ruegeria and Bdellovibrio) had significantly decreased populations (P
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Isolation and identification of Vibrio mediterranei 117-T6 as a pathogen associated with yellow spot disease of Pyropia (Bangiales, Rhodophyta)
Aquaculture, 2020Co-Authors: Rui Yang, Qiqin Liu, Qijun Luo, Zhen Tao, Juanjuan Chen, Haimin ChenAbstract:Abstract Pyropia is an important cultivated seaweed in Northeast Asia. Yellow spot disease (YSD) commonly occurs in Conchocelis sporeling cultures of Pyropia and causes huge economic losses. In this study, the isolated strain 117-T6 was identified as a pathogenic bacterium of YSD in Pyropia by Koch's postulates. Based on the morphological, physiological, and biochemical characteristics and multi-locus analysis of house-keeping gene sequences, this gram-negative bacterium was named as Vibrio mediterranei 117-T6. V. mediterranei 117-T6, including its intracellular and the extracellular extracts, caused both free-living Conchocelis (FLC) and shell-borne Conchocelis (SBC) to exhibit YSD symptoms within 12 days, indicating that the bacteria might attack Pyropia by secreting certain compounds that can be transported into algal cells, breaking down their structure and leading to death. During the infection, four stages were observed. 1) Prophase: a large number of pathogenic bacteria gathered around the algae. The Conchocelis was in healthy condition at that time. 2) Early stage: organelle edges of Pyropia were blurred, mitochondria and chloroplasts became fluffy and unraveled, autophagosomes appeared. 3) Middle stage: cellular structures and contents of the algae kept being lost and degraded, cell walls became thin. 4) Late stage: the Conchocelis bleached completely, and as the cell wall disintegrated gradually, the bacteria took over the remains of Pyropia. Finally, the whole algal cell disappeared, which may be the reason for shell bleaching. Our results show that YSD caused by V. mediterranei 117-T6 is a severe disease of algal disintegration caused by bacterial secretion, with a short onset and severe symptoms.
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Different Responses to Heat Shock Stress Revealed Heteromorphic Adaptation Strategy of Pyropia
2016Co-Authors: Haitanensis Rhodophyta, Haimin Chen, Rui Yang, Qijun Luo, Zhenggang Zhu, Zhujun Zhu, Feijian Qian, Xiaojun YanAbstract:Pyropia has a unique heteromorphic life cycle with alternation stages between thallus and Conchocelis, which lives at different water temperatures in different seasons. To better understand the different adaptation strategies for temperature stress, we tried to observe comparative biochemical changes of Pyropia haitanensis based on a short term heat shock model. The results showed that: (1) At normal temperature, free-living Conchocelis contains significantly higher levels of H2O2, fatty acid-derived volatiles, the copy number of Phrboh and Phhsp70 genes,the activities of NADPH oxidase and floridoside than those in thallus. The released H2O2 and NADPH oxidase activity of Conchocelis were more than 7 times higher than those of thallus. The copy number of Phrboh in Conchocelis was 32 times that in thallus. (2) After experiencing heat shock at 35uC for 30 min, the H2O2 contents, the mRNA levels of Phrboh and Phhsp70, NADPH oxidase activity and the floridoside content in thallus were all significantly increased. The mRNA levels of Phrboh increased 5.78 times in 5 min, NADPH oxidase activity increased 8.45 times in 20 min. (3) Whereas, in Conchocelis, the changes in fatty acids and their down-stream volatiles predominated, significantly increasing levels of saturated fatty acids and decreasing levels of polyunsaturated fatty acids occurred, and the 8-carbon volatiles were accumulated. However, the changes in H2O2 content and expression of oxidant-related genes and enzymatic activity were not obvious. Overall, these results indicate that Conchocelis maintains a high level of active protective apparatus to endure its survival at high temperature, while thallu
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Different responses to heat shock stress revealed heteromorphic adaptation strategy of Pyropia haitanensis (Bangiales, Rhodophyta).
PloS one, 2014Co-Authors: Qijun Luo, Haimin Chen, Rui Yang, Zhenggang Zhu, Zhujun Zhu, Feijian Qian, Xiaojun YanAbstract:Pyropia has a unique heteromorphic life cycle with alternation stages between thallus and Conchocelis, which lives at different water temperatures in different seasons. To better understand the different adaptation strategies for temperature stress, we tried to observe comparative biochemical changes of Pyropia haitanensis based on a short term heat shock model. The results showed that: (1) At normal temperature, free-living Conchocelis contains significantly higher levels of H2O2, fatty acid-derived volatiles, the copy number of Phrboh and Phhsp70 genes,the activities of NADPH oxidase and floridoside than those in thallus. The released H2O2 and NADPH oxidase activity of Conchocelis were more than 7 times higher than those of thallus. The copy number of Phrboh in Conchocelis was 32 times that in thallus. (2) After experiencing heat shock at 35°C for 30 min, the H2O2 contents, the mRNA levels of Phrboh and Phhsp70, NADPH oxidase activity and the floridoside content in thallus were all significantly increased. The mRNA levels of Phrboh increased 5.78 times in 5 min, NADPH oxidase activity increased 8.45 times in 20 min. (3) Whereas, in Conchocelis, the changes in fatty acids and their down-stream volatiles predominated, significantly increasing levels of saturated fatty acids and decreasing levels of polyunsaturated fatty acids occurred, and the 8-carbon volatiles were accumulated. However, the changes in H2O2 content and expression of oxidant-related genes and enzymatic activity were not obvious. Overall, these results indicate that Conchocelis maintains a high level of active protective apparatus to endure its survival at high temperature, while thallus exhibit typical stress responses to heat shock. It is concluded that Pyropia haitanensis has evolved a delicate strategy for temperature adaptation for its heteromorphic life cycle.
Qiqin Liu - One of the best experts on this subject based on the ideXlab platform.
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Bacteriophage therapy on the Conchocelis of Pyropia haitanensis (Rhodophyta) infected by Vibrio mediterranei 117-T6
Aquaculture, 2021Co-Authors: Junkai Zhu, Qiqin Liu, Rui Yang, Haimin ChenAbstract:Abstract Yellow spot disease (YSD) is a destructive disease that usually occurs at the Conchocelis nursery stage of commercially cultivated Pyropia species. Vibrio mediterranei 117-T6 has been identified as the pathogenic bacteria causing YSD. To develop a biological control program for YSD, we investigated the effects of bacteriophage vB_VmeM-Yong XC31 (phage XC31) on the density of the pathogenic bacteria, the physiological and biochemical parameters of the free-living Conchocelis (FLC) and the shell-borne Conchocelis (SBC) of Pyropia haitanensis infected by V. mediterranei 117-T6. The highest survival rate (83%) of infected FLC was obtained when the density of V. mediterranei 117-T6 was 108 CFU/mL and the multiplicity of infection (MOI) of phage XC31 was 1. Under these conditions, phage XC31 could kill the pathogens and significantly decrease the Vibrio density in the infection system (P
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Changes in phycospheric and environmental microbes associated with an outbreak of yellow spot disease on Pyropia yezoensis
Aquaculture, 2020Co-Authors: Qiqin Liu, Yajun Zhi, Zhiming Ren, Haimin Chen, Rui YangAbstract:Abstract The composition and diversity of phycospheric microbes are critical to the health of algae. Pyropia yezoensis is a popular edible seaweed in Asia and yellow spot disease (YSD) is a serious disease during its Conchocelis sporeling culture period. We studied the changes of the bacterial flora in the phycosphere and the surrounding seawater of P. yezoensis Conchocelis during a YSD outbreak and treatment. Four types of algal conditions were studied 1) healthy (no previous YSD); 2) YSD; 3) YSD being treated with ClO2 and 4) recovery (14 d after treatment). In the YSD samples, the microbial diversity was significantly decreased. The abundance of bacteria that were reported having algal dissolving and degrading functions (Kangiella, Alteromonas, Kordiimona, Tenacibaculum and Winogradskyella) was significantly increased, and some beneficial bacteria (Ruegeria and Bdellovibrio) had significantly decreased populations (P
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Isolation and identification of Vibrio mediterranei 117-T6 as a pathogen associated with yellow spot disease of Pyropia (Bangiales, Rhodophyta)
Aquaculture, 2020Co-Authors: Rui Yang, Qiqin Liu, Qijun Luo, Zhen Tao, Juanjuan Chen, Haimin ChenAbstract:Abstract Pyropia is an important cultivated seaweed in Northeast Asia. Yellow spot disease (YSD) commonly occurs in Conchocelis sporeling cultures of Pyropia and causes huge economic losses. In this study, the isolated strain 117-T6 was identified as a pathogenic bacterium of YSD in Pyropia by Koch's postulates. Based on the morphological, physiological, and biochemical characteristics and multi-locus analysis of house-keeping gene sequences, this gram-negative bacterium was named as Vibrio mediterranei 117-T6. V. mediterranei 117-T6, including its intracellular and the extracellular extracts, caused both free-living Conchocelis (FLC) and shell-borne Conchocelis (SBC) to exhibit YSD symptoms within 12 days, indicating that the bacteria might attack Pyropia by secreting certain compounds that can be transported into algal cells, breaking down their structure and leading to death. During the infection, four stages were observed. 1) Prophase: a large number of pathogenic bacteria gathered around the algae. The Conchocelis was in healthy condition at that time. 2) Early stage: organelle edges of Pyropia were blurred, mitochondria and chloroplasts became fluffy and unraveled, autophagosomes appeared. 3) Middle stage: cellular structures and contents of the algae kept being lost and degraded, cell walls became thin. 4) Late stage: the Conchocelis bleached completely, and as the cell wall disintegrated gradually, the bacteria took over the remains of Pyropia. Finally, the whole algal cell disappeared, which may be the reason for shell bleaching. Our results show that YSD caused by V. mediterranei 117-T6 is a severe disease of algal disintegration caused by bacterial secretion, with a short onset and severe symptoms.
Guangce Wang - One of the best experts on this subject based on the ideXlab platform.
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Characterization of photosynthetic protein complexes in Conchocelis and blades of Pyropia yezoensis (Rhodophyta)
Algal Research, 2020Co-Authors: Zhenbing Zheng, Shan Gao, Guangce WangAbstract:Abstract The red alga Pyropia yezoensis is an economically important marine crop whose life cycle includes two distinct stages: Conchocelis and blades. These two types of thalli live in significantly different environments and have distinct shapes and physiological features. The photosynthetic apparatus of red algae, especially the light harvesting antenna, is unique. However, little is known about the photosynthetic apparatus of P. yezoensis. We studied the composition and organization of thylakoid membranes in Conchocelis and blades of P. yezoensis and found that the photosynthetic complexes differed between the two stages. Conchocelis had much higher photosystem I (PSI)/ photosystem II and PSI/Cytochrome b6/f ratios compared with blades. Additionally, a macromolecular protein complex that bound with lutein and Chlorophyll a was detected in Conchocelis but not in blades. The number and types of light harvesting complex subunits associated with PSI and the corresponding pigment binding also varied between Conchocelis and blades. These differences are an important strategy that allows the two P. yezoensis stages to adapt to various environments.
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Photosynthetic and metabolic analyses reveal a higher resistance to salinity in the Pyropia yezoensis (Rhodophyta) blades than in the Conchocelis
Algal Research, 2019Co-Authors: Aiyou Huang, Jianfeng Niu, Xiujun Xie, Guangce WangAbstract:Abstract The life cycle of Pyropia yezoensis contains two obviously different stages: the Conchocelis and the blade, which have different ploidy and morphology. The Conchocelis grows in a calcareous matrix within subtidal zone and cannot live without seawater. However, the blades live on intertidal rocks and experience severe stress conditions at low tide. When exposed to air, external salt concentration increases around the algal tissues. It has been reported that the blade has high tolerance to various stresses, including high salinity stress. However, it is unknown whether carbon fixation still occurs when the blade is exposed to high salinity stress. Furthermore, there has been very little research on the Conchocelis response to salt stress. Therefore, it is important to comprehensively compare the responses of the Conchocelis and the blades to salinity. In this study, photosynthesis performance, carbon metabolism, and metabolite production were measured. The Y(II) for the Conchocelis was almost zero (0.006) after 1 h at 120 practical salinity units (psu), whereas Y(I) was high (0.175). The Y(II) of the blade was only 0.008 whereas its Y(I) was 0.304 after 72 h at 120 psu, which suggests that PSII is more sensitive to salinity than PSI in both the Conchocelis and the blade. Higher relative abundance was detected in the blade over the whole experimental period, which showed that the blade had higher carbon fixation efficiency than the Conchocelis. The proline and trehalose contents were also higher in the blade, which might explain why the blade can tolerate higher salinities than the Conchocelis.
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Induction and characterization of green pigmentation mutant in Porphyra yezoensis Ueda
Aquaculture, 2008Co-Authors: Guangce Wang, Jianfeng Niu, Xiao Lei Fan, Bai Cheng ZhouAbstract:The free living Conchocelis of Porphyra yezoensis Ueda was treated with N-methyl-N-nitro-N-nitrosoguanidine to induce pigmentation mutants. The artificial green pigmentation mutant of P. yezoensis Conchocelis, which was composed entirely of green cells, was isolated through visualization with the unaided eye. The acquired green Conchocelis was further developed into a green gametophytic blade. This mutant was relatively stable in color in both gametophytic blade and Conchocelis phases. The gametophytic blade mutant was successively cultivated for commerce at some Porphyra farms in Rudong, China, and few wild type or sectorially variegated gametophytic blade occurred, indicating that the green mutant has commercial value. The green mutant was characterized as having lower phycoerythrin and higher phycocyanin content, and SDS-PAGE suggested that phycoerythrin was missing the gamma-subunit in comparison to the wild type. The wild type and the green mutant showed a clear difference in 02 evolution rates in white, green, yellow, and red light, which might be due to the qualitative and quantitative changes of phycoerythrin, and the quantitative difference of phycocyanin. (C) 2008 Elsevier B.V. All rights reserved.
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Characterization of the life history of Bangia fuscopurpurea (Bangiaceae, Rhodophyta) in connection with its cultivation in China
Aquaculture, 2008Co-Authors: Wen-jun Wang, Jianyi Zhu, Xiang-zhi Lin, Chun-kai Huang, Wu-lin Song, Guang Peng, Guangce WangAbstract:Bangia fuscopurpurea (Rhodophyta) was cultivated in Putian (Fujian province, China). The characteristics of the life history concerned with cultivation were investigated and the cultivation procedure was presented. The gametophytic phase (thallus) and the sporophytic phase (Conchocelis) occurred alternately in the life history of B. fuscopurpurea. Young thalli produced archeospores, and the number depended on the environmental factors. Temperature affected the number of archeospore release and percent of germination, and photo flux density (PFD) mainly affected the time of spore release and germination. Thalli matured from December to February and developed into the Conchocelis phase through sexual reproduction. The Conchocelis grown in shells had three developmental stages: vegetative Conchocelis, conchosporangiall formation and conchospore formation. Pit-connections were present in the first 2 stages but absent after conchospore formation. Vegetative Conchocelis and conchosporangial. branches can transform into each other. However, conchospores only developed into the gametophytic phase. Cultivation of B. fuscopurpurea was based on characterization of the life history, consisting of 3 steps: zygotospores collection, indoor cultivation of Conchocelis and outdoor cultivation of thalli. Young thalli that developed from conchospores produced numerous archeospores before December. Over 90% of the crop was from the development of archeospores. The results indicated that conchosporelings were a good source of archeospores, and the development of the large quantity of archeospores acted as a more prevailing means to increase the population size. (C) 2008 Elsevier B.V. All rights reserved.
Qijun Luo - One of the best experts on this subject based on the ideXlab platform.
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Isolation and identification of Vibrio mediterranei 117-T6 as a pathogen associated with yellow spot disease of Pyropia (Bangiales, Rhodophyta)
Aquaculture, 2020Co-Authors: Rui Yang, Qiqin Liu, Qijun Luo, Zhen Tao, Juanjuan Chen, Haimin ChenAbstract:Abstract Pyropia is an important cultivated seaweed in Northeast Asia. Yellow spot disease (YSD) commonly occurs in Conchocelis sporeling cultures of Pyropia and causes huge economic losses. In this study, the isolated strain 117-T6 was identified as a pathogenic bacterium of YSD in Pyropia by Koch's postulates. Based on the morphological, physiological, and biochemical characteristics and multi-locus analysis of house-keeping gene sequences, this gram-negative bacterium was named as Vibrio mediterranei 117-T6. V. mediterranei 117-T6, including its intracellular and the extracellular extracts, caused both free-living Conchocelis (FLC) and shell-borne Conchocelis (SBC) to exhibit YSD symptoms within 12 days, indicating that the bacteria might attack Pyropia by secreting certain compounds that can be transported into algal cells, breaking down their structure and leading to death. During the infection, four stages were observed. 1) Prophase: a large number of pathogenic bacteria gathered around the algae. The Conchocelis was in healthy condition at that time. 2) Early stage: organelle edges of Pyropia were blurred, mitochondria and chloroplasts became fluffy and unraveled, autophagosomes appeared. 3) Middle stage: cellular structures and contents of the algae kept being lost and degraded, cell walls became thin. 4) Late stage: the Conchocelis bleached completely, and as the cell wall disintegrated gradually, the bacteria took over the remains of Pyropia. Finally, the whole algal cell disappeared, which may be the reason for shell bleaching. Our results show that YSD caused by V. mediterranei 117-T6 is a severe disease of algal disintegration caused by bacterial secretion, with a short onset and severe symptoms.
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Different Responses to Heat Shock Stress Revealed Heteromorphic Adaptation Strategy of Pyropia
2016Co-Authors: Haitanensis Rhodophyta, Haimin Chen, Rui Yang, Qijun Luo, Zhenggang Zhu, Zhujun Zhu, Feijian Qian, Xiaojun YanAbstract:Pyropia has a unique heteromorphic life cycle with alternation stages between thallus and Conchocelis, which lives at different water temperatures in different seasons. To better understand the different adaptation strategies for temperature stress, we tried to observe comparative biochemical changes of Pyropia haitanensis based on a short term heat shock model. The results showed that: (1) At normal temperature, free-living Conchocelis contains significantly higher levels of H2O2, fatty acid-derived volatiles, the copy number of Phrboh and Phhsp70 genes,the activities of NADPH oxidase and floridoside than those in thallus. The released H2O2 and NADPH oxidase activity of Conchocelis were more than 7 times higher than those of thallus. The copy number of Phrboh in Conchocelis was 32 times that in thallus. (2) After experiencing heat shock at 35uC for 30 min, the H2O2 contents, the mRNA levels of Phrboh and Phhsp70, NADPH oxidase activity and the floridoside content in thallus were all significantly increased. The mRNA levels of Phrboh increased 5.78 times in 5 min, NADPH oxidase activity increased 8.45 times in 20 min. (3) Whereas, in Conchocelis, the changes in fatty acids and their down-stream volatiles predominated, significantly increasing levels of saturated fatty acids and decreasing levels of polyunsaturated fatty acids occurred, and the 8-carbon volatiles were accumulated. However, the changes in H2O2 content and expression of oxidant-related genes and enzymatic activity were not obvious. Overall, these results indicate that Conchocelis maintains a high level of active protective apparatus to endure its survival at high temperature, while thallu
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Different responses to heat shock stress revealed heteromorphic adaptation strategy of Pyropia haitanensis (Bangiales, Rhodophyta).
PloS one, 2014Co-Authors: Qijun Luo, Haimin Chen, Rui Yang, Zhenggang Zhu, Zhujun Zhu, Feijian Qian, Xiaojun YanAbstract:Pyropia has a unique heteromorphic life cycle with alternation stages between thallus and Conchocelis, which lives at different water temperatures in different seasons. To better understand the different adaptation strategies for temperature stress, we tried to observe comparative biochemical changes of Pyropia haitanensis based on a short term heat shock model. The results showed that: (1) At normal temperature, free-living Conchocelis contains significantly higher levels of H2O2, fatty acid-derived volatiles, the copy number of Phrboh and Phhsp70 genes,the activities of NADPH oxidase and floridoside than those in thallus. The released H2O2 and NADPH oxidase activity of Conchocelis were more than 7 times higher than those of thallus. The copy number of Phrboh in Conchocelis was 32 times that in thallus. (2) After experiencing heat shock at 35°C for 30 min, the H2O2 contents, the mRNA levels of Phrboh and Phhsp70, NADPH oxidase activity and the floridoside content in thallus were all significantly increased. The mRNA levels of Phrboh increased 5.78 times in 5 min, NADPH oxidase activity increased 8.45 times in 20 min. (3) Whereas, in Conchocelis, the changes in fatty acids and their down-stream volatiles predominated, significantly increasing levels of saturated fatty acids and decreasing levels of polyunsaturated fatty acids occurred, and the 8-carbon volatiles were accumulated. However, the changes in H2O2 content and expression of oxidant-related genes and enzymatic activity were not obvious. Overall, these results indicate that Conchocelis maintains a high level of active protective apparatus to endure its survival at high temperature, while thallus exhibit typical stress responses to heat shock. It is concluded that Pyropia haitanensis has evolved a delicate strategy for temperature adaptation for its heteromorphic life cycle.
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PCA scores scatter plot for the volatiles of P. haitanensis in responding to heat shock.
2014Co-Authors: Qijun Luo, Haimin Chen, Rui Yang, Zhenggang Zhu, Zhujun Zhu, Feijian Qian, Xiaojun YanAbstract:A, PCA scores scatter plot for the volatiles of thallus and Conchocelis of P. haitanensis. B and C represented PCA scores scatter plots for the volatiles of control and heat shocked thallus and Conchocelis, respectively.
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The enzyme activity of P. haitanensis in responding to heat shock.
2014Co-Authors: Qijun Luo, Haimin Chen, Rui Yang, Zhenggang Zhu, Zhujun Zhu, Feijian Qian, Xiaojun YanAbstract:A, NADPH oxidase activities and B, SOD activities of thallus and Conchocelis after heat shock at 35°C for 30 min. *P