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Tingting Gong - One of the best experts on this subject based on the ideXlab platform.

  • using stable isotope labeling to study the nitrogen metabolism in Anabaena flos aquae growth and anatoxin biosynthesis
    Water Research, 2017
    Co-Authors: Zongyao Qian, Chunlei Sun, Qiming Xian, Tingting Gong
    Abstract:

    Freshwater resources are under stress around the world due to rapid urbanization and excessive water consumption. Cyanobacterial blooms have occurred frequently in surface waters, which produced toxic secondary metabolites causing a potential harm to aquatic ecosystems and humans. In this study, the relationship between different types of nitrogen source and the algal growth of Anabaena Flos-Aquae, which was isolated from Dianchi Lake in southern China, was investigated. Experiments were accomplished by using four types of isotope tracers including 15N-ammonium chloride, 15N-sodium nitrate, 15N-urea, 15N-l-alanine in culture medium to characterize the biosynthesis of 15N-anatoxin-a (ATX-A), which is a major algal toxin from A. Flos-Aquae, through liquid chromatography-tandem mass spectrometry (LC-MS/MS). The results showed that all these four types of nitrogen can be incorporated into algal cells. The ATX-A production with urea as the nitrogen source was much higher than that with the other three types of nitrogen. The 15N labeling experiments further demonstrated that the uptake of organic nitrogen nutrients was significantly greater than that of inorganic nitrogen. These results provide new evidence and deeper insight to explore the biosynthesis of ATX-A in the specific strain of A. Flos-Aquae.

M A Eldib - One of the best experts on this subject based on the ideXlab platform.

  • uptake and the effects of cyanazine on scenedesmus obliquus and Anabaena flos aquae
    Desalination, 2009
    Co-Authors: Azza M Abdelaty, M A Eldib
    Abstract:

    Abstract Microalgal species vary in their sensitivity to the triazine herbicides, including cyanazine. The current investigation was carried out to examine the uptake and the effects of cyanazine on Chl (a) content, growth rate, EC50, and protein and amino acid contents of two different algal species; namely Scenedesmus obliquus (green alga) and Anabaena Flos-Aquae (blue green alga). With regard to the differential sensitivity, the present findings revealed that S. obliquus is more sensitive to the inhibitory effects of cyanazine compared to A. Flos-Aquae (EC50 = 26 vs. 113 µg/L, respectively). Additionally, the lowest applied concentrations of the tested herbicide increased the Chl (a) content of both algal cultures as well as its rate of uptake.

Byung Dae Yoon - One of the best experts on this subject based on the ideXlab platform.

  • NOTE ESTABLISHMENT OF AXENIC CULTURES OF Anabaena FLOS‐AQUAE AND APHANOTHECE NIDULANS (CYANOBACTERIA) BY LYSOZYME TREATMENT
    Journal of Phycology, 1999
    Co-Authors: Yong Ha Park, Byung Dae Yoon, Hee-mock Oh
    Abstract:

    A new method using lysozyme for the production of axenic cultures of Anabaena Flos-Aquae De Brebisson and Aphanothece nidulans P. Richter was developed. Cyanobacterial growth was not inhibited at concentrations up to 1.2 g·L−1 of lysozyme, whereas the growth of heterotrophic bacteria was suppressed. At concentrations up to 0.8 g·L−1 of lysozyme, ampicillin caused a reduction of heterotrophic bacteria. The axenic cultures of these strains were acquired through a simple treatment using 1.0 g·L−1 of lysozyme without ampicillin. These cyanobacteria resisted digestion by lysozyme at our experimental concentrations, whereas bacteria were digested selectively. This method of purification seems to be especially useful with cyanobacterial species that are sensitive to antibiotics or other germicidal agents.

  • note establishment of axenic cultures of Anabaena flos aquae and aphanothece nidulans cyanobacteria by lysozyme treatment
    Journal of Phycology, 1999
    Co-Authors: Jung Seok Kim, Yong Ha Park, Byung Dae Yoon
    Abstract:

    A new method using lysozyme for the production of axenic cultures of Anabaena Flos-Aquae De Brebisson and Aphanothece nidulans P. Richter was developed. Cyanobacterial growth was not inhibited at concentrations up to 1.2 g·L−1 of lysozyme, whereas the growth of heterotrophic bacteria was suppressed. At concentrations up to 0.8 g·L−1 of lysozyme, ampicillin caused a reduction of heterotrophic bacteria. The axenic cultures of these strains were acquired through a simple treatment using 1.0 g·L−1 of lysozyme without ampicillin. These cyanobacteria resisted digestion by lysozyme at our experimental concentrations, whereas bacteria were digested selectively. This method of purification seems to be especially useful with cyanobacterial species that are sensitive to antibiotics or other germicidal agents.

E. S. Kravchuk - One of the best experts on this subject based on the ideXlab platform.

  • Seasonal dynamics of akinetes of Anabaena Flos-Aquae in the bottom sediments and water column of a small Siberian reservoir
    Contemporary Problems of Ecology, 2009
    Co-Authors: E. S. Kravchuk
    Abstract:

    Seasonal dynamics of akinetes of Anabaena Flos-Aquae (Lyngb.) Breb. was studied in the sediments and the water column in profundal and littoral zones of a small Siberian reservoir. It was hypothesized that even in a shallow mixed reservoir cyanobacterial bloom initiates in the littoral zone and only then distributes throughout the water body. Two types of akinetes have been recognized: one type ensures vegetative reproduction, and the other, survival during adverse growth conditions. Seasonal dynamics of abundance of akinetes and vegetative cells was quite the same in water column in the littoral and profundal zones. However, there were differences in the seasonal dynamics of abundance of akinetes in the bottom sediments of these two areas: in the central zone the abundance increased throughout the vegetation period, whereas in the littoral zone the abundance decreased after settling of akinetes. During winter, the abundance of akinetes decreased in the sediments in both profundal and littoral zones. The explanation to this fact has not been found yet.

  • Spatial and Temporal Dynamics of Anabaena Flos-Aquae Akinetes in Bottom Sediments of a Small Siberian Reservoir
    Journal of Siberian Federal University. Biology, 2009
    Co-Authors: E. S. Kravchuk, Elena A. Ivanova
    Abstract:

    Spatial distribution of akinetes of Anabaena Flos-Aquae (cyanobacteria) in littoral bottom sediments of a small Siberian reservoir was studied. Akinete abundance in bottom sediments is found to be related with type of sediments and presence of higher water plants. The highest abundance of akinetes was observed in silty sediments at stations located in higher plants bed (mainly emerged plants Typha latifolia L. and Phragmites australis (Cav.) Trin. ex Steud.). These results demonstrate that macrophyte beds could increase the size of the potential cyanobacterial inoculum by accumulation of akinetes in shallow bottom sediments and, as a result, favour cyanobacterial bloom development. In addition, seasonal dynamics of Anabaena Flos-Aquae, including vegetative cells and akinetes, in bottom sediments and water column in open water and littoral of the reservoir was studied. Dynamics of Anabaena abundance in the water column at the central station and littoral stations were very similar, but the number of cells in the littoral achieved higher year maximum than that at the central station. The highest seasonal peak of vegetative cells and akinetes in the water column was observed at the littoral station, located in emerged higher plants bed. However, at this part of the reservoir lowest intensity of akinete production was recorded. Deposition of akinetes to bottom sediments occurred both in open water and littoral. Nevertheless, seasonal dynamics of akinetes in bottom sediments differed between these sites. At the central station accumulation of akinetes in bottom sediments occurred throughout the summer, but in the littoral abundance of akinetes decreased just after their sedimentation. Hence, abundance of akinetes in the littoral sediments of the reservoir is markedly lower than that in the deeper central part.

  • Seasonal dynamics of akinetes of Anabaena Flos-Aquae in bottom sediments and water column of small Siberian reservoir
    Aquatic Ecology, 2006
    Co-Authors: E. S. Kravchuk, Elena A. Ivanova, Michail I. Gladyshev
    Abstract:

    Seasonal dynamics of Anabaena Flos-Aquae (Lyngb.) Breb., including vegetative cells, akinetes and akinete envelopes, in bottom sediments and water column at both littoral and deeper central stations of a small Siberian reservoir was studied. Two types of akinetes were observed: in the first half of summer Anabaena formed akinetes, which served for vegetative reproduction and germinated in water column soon after differentiation, while in the second half of summer the akinetes produced served as a resting stages, which were deposited to bottom sediments. Canonical correlation analyses revealed that decrease of water temperature was the main environmental factor that stimulated the akinete formation. In contrast to the general opinion, concentration of inorganic phosphorus slightly, but positively influenced the akinete formation. Thus, akinetes formed in response to the temperature decrease, needs a certain level of this nutrient. At littoral and open-water stations abundance and seasonal dynamics of akinetes in water column and their sinking pattern were very similar. However, seasonal dynamics of abundance of akinetes in sediments in these two reservoir locations differed: whereas the abundance of akinetes in open water increased permanently during the summer, that in the littoral decreased soon after their sedimentation. The cause for decrease in abundance of akinetes in bottom sediments in winter is unknown.

John J. Gilbert - One of the best experts on this subject based on the ideXlab platform.

  • Susceptibility of planktonic rotifers to a toxic strain of Anabaena flos‐aquae
    Limnology and Oceanography, 1994
    Co-Authors: John J. Gilbert
    Abstract:

    Reproduction in Asplanchna girodi, Brachionus calyczjlorus, Keratella cochlearis, and Synchaeta pectinata fed Cryptomonas at 19°C was inhibited by the presence of a strain of Anabaena Flos-Aquae (IC- 1) producing the neurotoxic alkaloid anatoxin-a. The most susceptible species, B. calycz&!orus, was suppressed at an Anabaena dry mass concentration of 0.5 pg ml-*; the others were suppressed at a concentration of 4 pg ml-‘. Reproduction of all species at 19°C was inhibited by anatoxin-a; the most sensitive species (S. pectinata) was inhibited at a concentration of 0.2 fig ml-l, and the least sensitive species (B. CalyciJorus), was inhibited at a concentration of 5 pg ml-’ but not one of 2 pg ml-‘. In contrast, A. girodi and two clones of B. calyciflorus were not inhibited by filtrates of very dense Anabaena suspensions (1 : 1 and 1 : 3 dilutions of 1 -d-old, 80 pg ml-r suspensions); this showed that the Anabaena did not release extracellular toxin, and thus that it could only inhibit rotifers that ingested it. B. calyczjlorus probably was the most susceptible to the cyanobacterium, even though it was the least sensitive to the soluble toxin, because it ingested the filaments most efficiently. Its relatively low sensitivity to the toxin may reflect an evolutionary response to its greater tendency to ingest toxic cyanobacteria. The effect of a toxic cyanobacterium on the structure of a freshwater zooplankton community should depend on the size and morphology of its colonies. Large colonies should be more readily ingested by daphniids than rotifers, and hence more likely to inhibit competitively dominant daphniids. Small, amorphous colonies or short, thin, nonmucilagecoated filaments should be ingested by, and thus inhibit, some rotifers as well as daphniids.