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Lirong Song - One of the best experts on this subject based on the ideXlab platform.
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2-Methylisoborneol production characteristics of Pseudanabaena sp. FACHB 1277 isolated from Xionghe Reservoir, China
Journal of Applied Phycology, 2016Co-Authors: Ting Zhang, Lingling Zheng, Lirong SongAbstract:The cyanobacterium Pseudanabaena sp. FACHB 1277, a 2-methylisoborneol (2-MIB) producer isolated from Xionghe Reservoir, was identified by molecular biological methods based on the 16S rDNA sequence. Pseudanabaena sp. FACHB 1277 is a planktonic freshwater species with relatively high 2-MIB per cell density value (7.76 × 10−6 ng cell−1) and specific growth rate (0.25 ± 0.01 d−1). The effects of temperature and light intensity on 2-MIB production of Pseudanabaena sp. FACHB 1277 were investigated. Of the six temperatures tested, 10, 15, 20, 25, 30, and 35 °C, the maximum total 2-MIB per cell density and minimum cell density were observed at 10 °C, while the total 2-MIB and dissolved 2-MIB (including extracellular and dissolved intracellular 2-MIB) increased with increasing temperature. Among the six tested light intensities (10, 25, 40, 55, 70, and 85 μmol photons m−2 s−1), the minimum total 2-MIB per cell density and maximum cell density were observed at 25 μmol photons m−2 s−1. The total 2-MIB and extracellular 2-MIB increased with light intensity increasing from 10 to 40 μmol photons m−2 s−1, while no significant increase was observed when the light intensity was higher than 40 μmol photons m−2 s−1. The maximum intracellular 2-MIB (including dissolved and bound) occurred at 25 μmol photons m−2 s−1. The present study indicates that increasing temperature could favor the conversion of bound intracellular to dissolved 2-MIB, while increasing light intensity stimulates the release of dissolved intracellular 2-MIB into the environment.
Donald A Bryant - One of the best experts on this subject based on the ideXlab platform.
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Organization and transcription of the genes encoding two differentially expressed phycocyanins in the cyanobacterium Pseudanabaena sp. PCC 7409
Photosynthesis Research, 1993Co-Authors: James M. Dubbs, Donald A BryantAbstract:The cpc1 and cpc2 operons of the group III chromatically adapting cyanobacterium Pseudanabaena sp. PCC 7409 were isolated and their nucleotide sequences determined. The cpc1 operon consists of the genes cpcB1A1EF and gives rise to an abundant 1400-nucleotide transcript encoding the cpcB1A1 genes and two low-abundance transcripts of 1000 nucleotides and 1100 nucleotides encoding the cpcF gene. Two extremely low-abundance transcripts of approximately 2900 nucleotides and 4800 nucleotides possibly encode cpcB1A1E and cpcB1A1EF , respectively. All transcripts were present in cultures grown in either red or green light. The transcription start of the cpcB1A1 mRNA was mapped to a position 238 bp 5′ to the cpcB1 translation start. The cloned fragment containing the cpcB2A2 genes was found to contain only a portion of the cpc2 operon and consisted of the cpcB2A2 genes and the 5′ portion of the linker gene cpcH2 . On the basis of biochemical evidence, as well as sequence data from other cpc operons, it is probable that the complete Pseudanabaena sp. PCC 7409 cpc2 operon consists of the genes cpcB2A2H2I2D2 . This operon is almost exclusively transcribed in cells grown in red light and gives rise to an abundant mRNA 1400 nucleotides in length that encodes the cpcB2A2 genes. A second transcript of 2400 nucleotides encodes the cpcB2A2H2 genes. A third transcript of 3800 nucleotides encodes the cpcB2A2H2 genes and probably the cpcI2 and cpcD2 genes as well. Transcription of the cpc2 mRNAs inititates 219 bp 5′ to the cpcB2 translation start. The promoter region of the Pseudanabaena sp. PCC 7409 cpc1 operon contains the sequence 5′ ttGTATaa 3′ that is also found to occur within 20 bp of the transcription initiation sites of a number of other constitutively expressed cpc promoters. A high level of sequence similarity also occurs between the red-light-inducible cpc2 promoters of Pseudanabaena sp. PCC 7409 and Calothrix sp. PCC 7601.
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Molecular cloning and transcriptional analysis of the cpeBA operon of the cyanobacterium Pseudanabaena species PCC 7409
Molecular microbiology, 1991Co-Authors: James M. Dubbs, Donald A BryantAbstract:Summary The cpeBA operon of the Group III chromatically adapting cyanobacterium Pseudanabaena species PCC 7409 was cloned, sequenced and characterized. The cpeBA genes are transcribed in green-light-grown cells as an abundant 1400-nucleotide mRNA which initiates 69 nucleotides upstream from the cpeB translation start. Extensive sequence identity, extending 70 nucleotides 5′ to the transcription start, occurs among cpeBA promoters of Group II and III chromatic adapters. Cell extracts of green-light-grown Calothrix species PCC 7601 contain an activity which specifically binds a restriction fragment containing the Pseudanabanea species PCC 7409 cpeBA promoter. Green-light-dependent cpeBA transcription in Group II and III chromatically adapting cyanobacteria is suggested to be similarly controlled by a transcriptional activator.
Dong Wenyi - One of the best experts on this subject based on the ideXlab platform.
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Dominance and growth factors of Pseudanabaena sp. in drinking water source reservoirs, Southern China.
Sustainability, 2018Co-Authors: Gao Jingsi, Jia Zhu, Maowei Wang, Dong WenyiAbstract:Pseudanabaena sp. is a common and harmful species in freshwater cyanobacteria blooms. There are very few studies on its distribution characteristics and growth influencing factors. In the current study, it was found to be dominant in three cascading reservoirs in Southern China. Field observations and laboratory experiments were integrated to investigate the dominance and growth factors of Pseudanabaena sp. The effects of temperature, light intensity, nutrients, chemical oxygen demand (COD), pH, and disturbance on Pseudanabaena sp. growth were evaluated. The results indicated that Pseudanabaena sp. had significant positive correlations with water temperature, pH, and COD (p 3 -N (p < 0.05). The optimum growth temperature range for Pseudanabaena sp. was from 20 to 30 °C; hence, it usually has outbreaks in May and August. The optimum light intensity and pH for Pseudanabaena sp. were 27 μmol photons m−2s−1 and from 7 to 9, respectively. The superior tolerance for low light, disturbance, and phosphorus deficiency of Pseudanabaena sp. may be the main factors affecting its dominance in reservoirs. Controlling nitrogen was more effective than controlling phosphorus to avoid the risk that was brought by Pseudanabaena sp. This study contributed to the theoretical knowledge for the prediction and control of the growth of Pseudanabaena sp.
Karina Yew-hoong Gin - One of the best experts on this subject based on the ideXlab platform.
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Isolation and Characterization of the First Freshwater Cyanophage Infecting Pseudanabaena.
Journal of virology, 2020Co-Authors: Dong Zhang, Fang You, Karina Yew-hoong GinAbstract:Cyanobacteria are the major primary producers in both freshwater and marine environments. However, the majority of freshwater cyanophages remain unknown due to the limited number of cyanophage isolates. In this study, we present a novel lytic freshwater cyanophage, PA-SR01, which was isolated from the Singapore Serangoon Reservoir. To our knowledge, this is the first isolate of a cyanophage that has been found to infect the cyanobacterium Pseudanabaena PA-SR01 has a narrow host range, a short latent period, and is chloroform sensitive. Distinct from the majority of cyanophage isolates, PA-SR01 has a tailless morphology. It is a double-stranded DNA virus with a 137,012-bp genome. Functional annotation for the predicted open reading frames (ORFs) of the PA-SR01 genome identified genes with putative functions related to DNA metabolism, structural proteins, lysis, host-derived metabolic genes, and DNA packaging. Out of 166 predicted ORFs, only 17 ORFs have homology with genes with known function. Phylogenetic analysis of the major capsid protein and terminase large subunit further suggests that phage PA-SR01 is evolutionary distinct from known cyanophages. Metagenomics sequence recruitment onto the PA-SR01 genome indicates that PA-SR01 represents a new evolutionary lineage of phage which shares considerable genetic similarities with phage sequences in aquatic environments and could play key ecological roles.IMPORTANCE This study presents the isolation of the very first freshwater cyanophage, PA-SR01, that infects Pseudanabaena, and fills an important knowledge gap on freshwater cyanophages as well as cyanophages infecting Pseudanabaena.
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Data_Sheet_1_The Characteristics and Dynamics of Cyanobacteria–Heterotrophic Bacteria Between Two Estuarine Reservoirs – Tropical Versus Sub-Tropical Regions.docx
2018Co-Authors: Karina Yew-hoong GinAbstract:In this study, Illumina MiSeq sequencing technique was employed to explore the characteristics and dynamics of cyanobacteria–heterotrophic bacteria between two estuarine reservoirs in sub-tropical (reservoir A in Shanghai) and tropical (reservoir B in Singapore) regions. The results indicated that significant differences in bacterial community composition were found between two estuarine reservoirs, which influenced by varied environmental variables. The environmental heterogeneity in reservoir A was much higher, which indicated that the composition of bacterial community in reservoir A was more complex. In contrast, reservoir B provided a suitable and temperate water environment conditions for bacterial growth, which resulted in higher community diversity and less co-exclusion correlations. The molecular ecological network indicated that the presence of dominant bacterial community in each of the reservoir were significant different. These differences mainly reflected the responses of bacterial community to the variations of environmental variables. Although Synechococcus was the dominant cyanobacterial species in both reservoirs, it exhibited co-occurrence patterns with different heterotrophic bacteria between reservoirs. In addition, the cyanobacteria–heterotrophic bacteria interaction exhibited highly dynamic variations, which was affected by nutrition and survive space. Also, the co-occurrence of Microcystis and Pseudanabaena found in reservoir B implied that the non-N-fixing Microcystis accompanied with N-fixing Pseudanabeana occurrence in freshwater lakes, so as to better meet the demand for nitrogen source.
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The Characteristics and Dynamics of Cyanobacteria–Heterotrophic Bacteria Between Two Estuarine Reservoirs – Tropical Versus Sub-Tropical Regions
Frontiers Media S.A., 2018Co-Authors: Karina Yew-hoong GinAbstract:In this study, Illumina MiSeq sequencing technique was employed to explore the characteristics and dynamics of cyanobacteria–heterotrophic bacteria between two estuarine reservoirs in sub-tropical (reservoir A in Shanghai) and tropical (reservoir B in Singapore) regions. The results indicated that significant differences in bacterial community composition were found between two estuarine reservoirs, which influenced by varied environmental variables. The environmental heterogeneity in reservoir A was much higher, which indicated that the composition of bacterial community in reservoir A was more complex. In contrast, reservoir B provided a suitable and temperate water environment conditions for bacterial growth, which resulted in higher community diversity and less co-exclusion correlations. The molecular ecological network indicated that the presence of dominant bacterial community in each of the reservoir were significant different. These differences mainly reflected the responses of bacterial community to the variations of environmental variables. Although Synechococcus was the dominant cyanobacterial species in both reservoirs, it exhibited co-occurrence patterns with different heterotrophic bacteria between reservoirs. In addition, the cyanobacteria–heterotrophic bacteria interaction exhibited highly dynamic variations, which was affected by nutrition and survive space. Also, the co-occurrence of Microcystis and Pseudanabaena found in reservoir B implied that the non-N-fixing Microcystis accompanied with N-fixing Pseudanabeana occurrence in freshwater lakes, so as to better meet the demand for nitrogen source
Ting Zhang - One of the best experts on this subject based on the ideXlab platform.
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2-Methylisoborneol production characteristics of Pseudanabaena sp. FACHB 1277 isolated from Xionghe Reservoir, China
Journal of Applied Phycology, 2016Co-Authors: Ting Zhang, Lingling Zheng, Lirong SongAbstract:The cyanobacterium Pseudanabaena sp. FACHB 1277, a 2-methylisoborneol (2-MIB) producer isolated from Xionghe Reservoir, was identified by molecular biological methods based on the 16S rDNA sequence. Pseudanabaena sp. FACHB 1277 is a planktonic freshwater species with relatively high 2-MIB per cell density value (7.76 × 10−6 ng cell−1) and specific growth rate (0.25 ± 0.01 d−1). The effects of temperature and light intensity on 2-MIB production of Pseudanabaena sp. FACHB 1277 were investigated. Of the six temperatures tested, 10, 15, 20, 25, 30, and 35 °C, the maximum total 2-MIB per cell density and minimum cell density were observed at 10 °C, while the total 2-MIB and dissolved 2-MIB (including extracellular and dissolved intracellular 2-MIB) increased with increasing temperature. Among the six tested light intensities (10, 25, 40, 55, 70, and 85 μmol photons m−2 s−1), the minimum total 2-MIB per cell density and maximum cell density were observed at 25 μmol photons m−2 s−1. The total 2-MIB and extracellular 2-MIB increased with light intensity increasing from 10 to 40 μmol photons m−2 s−1, while no significant increase was observed when the light intensity was higher than 40 μmol photons m−2 s−1. The maximum intracellular 2-MIB (including dissolved and bound) occurred at 25 μmol photons m−2 s−1. The present study indicates that increasing temperature could favor the conversion of bound intracellular to dissolved 2-MIB, while increasing light intensity stimulates the release of dissolved intracellular 2-MIB into the environment.
