N. A. Aizdaicher

Toxicity, morphology and distribution of Pseudo-nitzschia calliantha, P. multistriata and P. multiseries (Bacillariophyta) from the northwestern Sea of Japan

Toxicity, morphology and distribution patterns of three bloom-forming species of the diatom genus Pseudo-nitzschia (potential producers of the neurotoxin domoic acid and causative organisms of amne ...

Effects of selenium on growth and ultrastructure of the marine unicellular alga Dunaliella salina (Chlorophyta)

This study examines the effects of selenium in concentrations of 0.01, 0.5, 1, 5, and 10 mg/liter on the growth and ultrastructure of the microalga Dunaliella salina. Selenium in concentrations of 0.01 and 0.5 mg/liter stimulated cell population growth, while the number of ultrastructural alterations was the same as in the control cells. At a selenium concentrations of 1 mg/liter, cell population growth slightly decreased by the end of the experiment, and there was some increase in the number of cells with damaged organoids and in the number of completely destroyed cells. As well, the excretory function of cell vacuoles was suppressed, and the autophagic activity of these vacuoles was activated to destroy the cytoplasm and nucleus. Concentrations of 5 and 10 mg/liter were toxic to D. salina, suppressing cell population growth and promoting extensive destructive changes. The threshold concentration of selenium for D. salina was 1 mg/liter, which is 1000 times greater than the maximum permissible concentration (MPC). The fact that the microalga was able to survive for several days in this concentration is indicative of its high resistance to selenium.

Toxic effects of detergents on the alga Plagioselmis prolonga (Cryptophyta)

The effect of sodium dodecyl sulfate (SDS) and the household synthetic detergents (HSDs) Kristall and Tix (0.1, 1, and 10 mg/l) on cell motility, cell number dynamics, and the growth rate of the alga Plagioselmis prolonga (Cryptophyta) is studied. Algal cell motility proved to be the most sensitive indicator of detergent toxicity. SDS was the least toxic: 1 mg SDS/l caused a short-term loss of motility in 10% of the algal cells. The HSD Tix was the most toxic: only 70% of the cells recovered motility after a 24 h exposure to 1 mg/l. The substances tested in a concentration of 10 mg/l caused mortality of the P. prolonga population. According to their toxic effect on P. prolonga, the investigated toxicants can be arranged as follows: SDS < Kristall < Tix.

Influence of laundry detergents on the abundance dynamics and physiological state of the benthic microalga Attheya ussurensis (Bacillariophyta) in laboratory culture

This study examines the influence of the detergents “Obychnyi poroshok” and “Ariel” (at 0.1, 1, and 10 mg/l) on the growth and physiological state of the benthic marine microalga Attheya ussurensis. Cell number, growth rate, and oxygen productivity turned out to be the most sensitive characteristics for evaluation of toxic effects, while the pH of the culture medium and the contents of chlorophyll a and carotenoids were more tolerant to detergent. Toxicants in concentrations of 0.1 and 1 mg/l had a weak inhibitory effect on the microalga A. ussurensis; at 10 mg/l, the detergent Ariel exerted a greater inhibitory effect on the microalga than Obychnyi poroshok did.

Influence of extrametabolites of marine microalgae on the reproduction of the bacterium Listeria monocytogenes

The biological potency of extrametabolites produced by marine microalgae against reproductive forms of Listeria monocytogenes is examined. Extrametabolites of marine microalgae in exponential growth phase had no effect on L. monocytogenes. In the middle steady-state growth phase, extrametabolites of algal cultures boosted the reproduction of Listeria. An exception was Skeletonema costatum: extrametabolites of this alga in the middle steady-state growth phase showed an antibacterial effect against L. monocytogenes.

Changes in the Fatty Acid Composition of Hepatopancreas of the Mollusk Mytilus trossulus Fed on Microalgae

The influence of diet on the fatty acid composition of the hepatopancreas of Mytilus trossulus was studied. Three groups of mollusks were fed monocultures of the microalgae Phaeodactylum tricornutum, Chaetoceros muelleri (Bacillariophyceae), and Nannochloropsis sp. (Eustigmatophyceae) for 10 days. After 10 days, the proportion of polyunsaturated fatty acids, mainly eicosapentaenoic and docosahexaenoic, increased in the total lipids of the hepatopancreas in all mollusk groups. The content of saturated fatty acids in the mussel tissues decreased and was not dependent on the amount in the algal diet. Toward the end of the experiment, the fatty acid composition of the hepatopancreas of mussels was similar irrespective of the fatty acid composition of their food. The fatty acid analysis of M. trossulus feces suggests a selective assimilation by mussels of predominantly the n-3 polyunsaturated fatty acids. The role of fatty acid metabolism in M. trossulus is discussed.

Biotesting of water quality in Peter the Great Bay with the use of the microalga Dunaliella salina and embryos and larvae of the sea urchin Scaphechinus mirabilis

Comparative biotesting was performed using embryos and larvae of the sea urchin Scaphechinus mirabilis and the microalga Dunaliella salina. These two species were taken as test organisms for estimating water quality in areas of various anthropogenic loads. Seawater from Nakhodka and Vostok bays, as well as from the southwestern part of Peter the Great Bay (Sea of Japan) near the Tumen River mouth, was tested. Water from Vostok and Nakhodka bays had a harmful effect on embryonic and larval development of the sea urchin. The algal culture kept in the water of Vostok Bay was depressed throughout the experiment, while development of the alga in the water from Nakhodka Bay hardly differed from the control but was unstable. Water from the southwestern part of Peter the Great Bay did not have any significant harmful effect on both test organisms. Embryos and larvae of the sea urchin S. mirabilis were several orders more sensitive to salinity changes and content of toxic agents; they responded more readily to changes in water quality than D. salina cells. Correspondingly, embryos and larvae of the sea urchin S. mirabilis were found to be a preferable test organism for assessment of pollution in various marine environments.

Content of photosynthetic pigments, growth, and cell size of microalga Phaeodactylum tricornutum in the copper-polluted environment

Effects of copper at concentrations of 0.13 and 0.25 mg/l on content of photosynthetic pigments, growth, size characteristics, and cell shape of Phaeodactylum tricornutum (Bacillariophyta) microalga were studied. The inhibitory effect of copper on growth parameters was shown to become stronger with increasing concentration of copper in the growth medium. In spite of considerable retardation of cell growth, the concentrations examined had no effect on the content of photosynthetic pigments though affected some morphometric parameters.

Effects of Detergents on in vitro Growth of Diatom Alga Thalassiosira pseudonana

The growth of the diatom alga Thalassiosira pseudonana was studied when exposed to an environment polluted by a detergent. We determined concentrations that inhibit cell division (10 mg/l) instead of algae growth (0.1 and 1 mg/l. It was shown that T. pseudonana can adapt to high detergent concentrations. The stimulation of the growth of Thalassiosira within a range of 0.03–0.08 mg/l concentration has been registered.

Influence of changes in sea water salinity on the growth, photosynthetic pigment content, and cell size of the benthic alga Attheya ussurensis Stonik, Orlova et Crawford, 2006 (Bacillariophyta)

The study deals with the effect of changes in salinity from 32 to 4‰ (at an interval of 4‰) on the growth, chlorophyll a and carotenoid contents, and cell size of the benthic alga Attheya ussurensis (Bacillariophyta). A. ussurensis showed high tolerance to reduced salinity and ability to adapt to salinity changes from 16 to 12‰. In this salinity range, the cells restored their shapes, sizes, and physiological functions. The number of cells and photosynthetic pigment content were highest at a salinity reduction to 24‰. At 8‰, algal cells remained alive, but the process of cell division was inhibited; as a result, the number of cells was significantly lower than in the control, the cells did not restore their sizes and shapes and remained deformed until the end of the experiment. A drop in salinity to 4‰ caused a complete loss of cell viability of A. ussurensis within a day of exposure to this factor.