On the cultivation of axenic red algae

Fries, Lisbeth

doi:10.1111/j.1399-3054.1963.tb08347.x

Cited by 98 publications

(23 citation statements)

References 18 publications

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“…Based on what is known for higher plants, glucose was added to the growing media to see its effect on NR activity. Fries (1963) showed for red algae (including six species) that glucose and other sugars have an effect on algal growth. Yokoya (1996) showed that an increment in growth and morphogenesis occurred in Gracilariopsis tenuifrons and Grateloupia dichotoma with the addition of 1% sucrose, although its presence in the culture media was not essential.…”

Section: Light Darkmentioning

confidence: 99%

Characterization of nitrate reductase activity in vitro in Gracilaria caudata J. Agardh (Rhodophyta, Gracilariales)

et al. 2007

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-(Characterization of nitrate reductase activity in vitro in Gracilaria caudata J. Agardh (Rhodophyta, Gracilariales)). The marine red alga Gracilaria caudata J. Agardh has been used in Brazil for agar extraction, mainly in the northeast region of the country. Nitrogen availability is the most important abiotic factor in seawater that limits the growth of seaweeds. The enzyme nitrate reductase (NR) is the key regulatory point in the nitrogen assimilation in photosynthetic organisms. This study describes an in vitro assay, characterizing the enzymatic activity of NR in terms of kinetic constants and stability, its oscillation during the day and glucose effect on NR modulation. Maximal peaks of NR activity were recorded at 20 °C and pH 8.0. The enzymatic stability in crude extracts stored at 3 ± 1 °C decreased significantly after 48 hours. Apparent Michaelis-Menten constants (K M ) for NADH and nitrate were 22 µM and 3.95 mM, respectively. Gracilaria caudata NR activity showed an oscillation under light:dark photoperiod (14:10 hours LD) with 3-fold higher activity during the light phase, peaking after 10 hours of light. Under optimal assay conditions, the maximal activity was 92.9 10 -3 U g -1 . The addition of glucose induced the enzymatic activity during the light and dark phase, evidencing a possible modulation of this enzyme by the photosynthesis. This relationship can be explained by the need of carbon skeletons, produced by the photosynthetic process, to incorporate the intermediary metabolites of nitrate assimilatory pathway, avoiding the toxic intracellular accumulation of nitrite and ammonium. The optimization of enzymatic assay protocols for NR is essential to establish appropriate conditions to study nutritional behaviour, compare different taxonomic groups and to understand its regulatory mechanism.Key words -agarophyte, Gracilaria caudata, nitrate reductase, nitrogen metabolism RESUMO -(Caracterização da atividade in vitro da enzima nitrato redutase em Gracilaria caudata J. Agardh (Gracilariales, Rhodophyta)). A alga vermelha Gracilaria caudata J. Agardh tem sido utilizada no Brasil para a extração de ágar, principalmente no Nordeste do país. Na água do mar, a disponibilidade de nitrogênio é o principal fator abiótico que limita o crescimento de macroalgas. A enzima nitrato redutase (NR) é o ponto chave na regulação da assimilação do nitrogênio em organismos fotossintetizantes. Este estudo descreve o ensaio in vitro para caracterizar a atividade enzimática da NR em termos de constantes cinéticas e estabilidade, avalia sua oscilação ao longo do dia e a influência da glicose na modulação dessa enzima. Picos máximos de atividade da NR foram observados a 20 °C e pH 8,0. A estabilidade enzimática do extrato bruto armazenado a 3 ± 1 °C foi significativamente reduzida após 48 horas. As constantes aparentes de Michaelis-Menten (K M ) para NADH e nitrato foram 22 µM e 3,95 mM, respectivamente. A atividade da NR apresentou oscilação sob fotoperíodo de 14 horas de luz e10 horas de escuro com três vezes ...

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Section: Light Darkmentioning

confidence: 99%

Characterization of nitrate reductase activity in vitro in Gracilaria caudata J. Agardh (Rhodophyta, Gracilariales)

et al. 2007

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“…All algal cultures used in the experiments were brought into axenic culture by treatments with antibiotics (Fries 1963), with the exception of Fucus spiralis L., which was sterilized by a chlorine solution (Fries 1977). The stock cultures are kept in the artificial seawater ASP6 F2 (Fries 1977).…”

Section: Methodsmentioning

confidence: 99%

Vanadium an essential element for some marine macroalgae

Fries

1982

Planta

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In some marine algae cultivated axenically in the artificial medium ASP6 F2 (pH 8.3) vanadium at 1-100 μg l(-1) increases the fresh weight. In the multicellular brown algaFucus spiralis 10 μg V I(-1) enhances the fresh weight by about 400% while in the green algaEnteromorpha compressa the yield is increased by 90%. Red algae do not respond to vanadium. InFucus morphological effects are displayed in more frequent branching and/or broader blades. No significant increase in the chlorophyll content could be demonstrated at the early stage at which these morphological effects first appeared. Later the chlorophyll content increased.

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“…Treatment with Triton X-100 detergent proved to be the most effective way to remove bacteria from the diatom cell wall and disintegrate bacterial aggregates. Some previously proposed procedures for deriving axenic cultures of microalgae involve treatment with iodine (Fries 1963), Betadine (Polne-Fuller and Gibor 1984), or Teepol (Hunt and Mandoli 1992), but we have not used these reagents.…”

Section: Discussionmentioning

confidence: 99%

A procedure for establishing an axenic culture of the diatom Synedra acus subsp. radians (Kütz.) Skabibitsch. from Lake Baikal

Shishlyannikov

Zakharova

Volokitina

et al. 2011

Limnology & Ocean Methods

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Production of axenic cultures of diatoms is a highly relevant task, as these widespread organisms are objects of research in different fields of biology, from ecology to whole-genome studies, and promising as producers of various organic molecules, including biologically active substances. However, culturing of diatoms isolated from natural communities is accompanied by the development of associated microorganisms. We propose a procedure for establishing an axenic culture of the freshwater diatom Synedra asus subsp. radians (Kütz.) Skabitsch. from Lake Baikal. Such a culture has been produced and maintained by subculturing in our laboratory. The procedure involves filtration (to remove free bacteria), detergent treatment (to remove microorganisms associated with diatom frustules), selection of effective antibiotics and their concentrations nontoxic for diatoms (by the disk diffusion method), cell treatment with the selected antibiotic (ciprofloxacin), repeated filtration, and monoclonal culturing of diatom cells. Axenity of the culture was verified microscopically (after DAPI staining) and by molecular biological methods.

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On the cultivation of axenic red algae

Cited by 98 publications

References 18 publications

Characterization of nitrate reductase activity in vitro in Gracilaria caudata J. Agardh (Rhodophyta, Gracilariales)

Characterization of nitrate reductase activity in vitro in Gracilaria caudata J. Agardh (Rhodophyta, Gracilariales)

Vanadium an essential element for some marine macroalgae

A procedure for establishing an axenic culture of the diatom Synedra acus subsp. radians (Kütz.) Skabibitsch. from Lake Baikal

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