Growth and ultrastructure of the marine unicellular alga <Emphasis Type="Italic">Dunaliella salina</Emphasis> (Chlorophyta) after chronic selenium intoxication

The effects of selenium (0.01, 0.5, 1, 5 and 10 mg/liter) on the growth and ultrastructure of the microalga Dunaliella salina were investigated following its transfer into clean water. Selenium concentrations of 5 and 10 mg/liter were toxic to D. salina, and reinoculation of microalga into clean water did not prevent it from total mortality. When reinoculated from medium with 0.01 mg Se/liter, the cell population density of D. salina was restored in 14 days. The number of ultrastructural alterations in cells was the same as in the control, while the excretory activity of microalga between days 4 and 10 of this experiment was higher. Cell population growth of D. salina transferred from 0.5 and 1 mg Se/liter was lower than in the control. No ultrastructural defects were observed in microalga reinoculated from medium with a selenium concentration of 0.5 mg/liter and the excretion level corresponded to that at 0.01 mg/liter. Various types of ultrastructural damage were found in microalga from medium with 1 mg Se/liter, which was previously reported to be threshold for D. salina; however, the number of cell injuries decreased with increasing time in clean medium. Excretory activity was decreased at the beginning of experiment; but after 7 days, it was restored to the control level. Though there were no ultrastructural alterations in microalgal cells from medium with 0.5 mg Se/liter, we assume that they had molecular defects that could inhibit the cell population growth. The study of microalgae following their reinoculation from medium containing toxicants into clean medium can be a useful method for evaluating algal survival after toxic exposure.     

Heavy Metals in Seagrasses and Algae of Pos'et Bay, Sea of Japan

The contents of heavy metals in Sargassum algae and seagrasses from Pos'et Bay in the Sea of Japan were studied. The concentrations of Fe, Mn, Cu, Zn, and Cr in the algae and seagrass leaves were correlated with each other. The concentrations of heavy metals in brown algae and seagrasses from Pos'et Bay were largely close to background levels. Increased contents of some metals found in macrophytes in the area of the port of Pos'et were due to local environmental pollution; around Furugel'm Island, to periodical upwelling and drift currents from the mouth of the Tumannaya River; and, at Cape Deger, to the cyclonic current.     

Concentrations of Heavy Metals in Soft Tissues of the Gastropod Nucella heyseanain the Vicinity of Vladivostok and in the Vostok Bay Reserve

A survey was made of 168 specimens of the gastropod mollusk Nucella heyseanafrom 5 samples collected in Amurskii Bay and Vostok Bay (Peter the Great Bay and the Sea of Japan). The variability of Cu, Zn, Cd, Pb, Fe, and Mn contents in gastropod soft tissues was analyzed. The statistic concentrations of the six metals differed significantly among the samples; they were sometimes taken at a distance of a mere several tens of meters apart. N. heyseanacollected near Vladivostok generally had higher concentrations of heavy metals; however, the amount of Zn in the specimens of one sample from the Vostok Bay Reserve was 400 g/g, which is two times greater than that of mollusks from the urbanized zone. The canonical and discriminant analyses and the analysis of the variance indicate that the variation in heavy metal concentration within groups of mollusks (within bays) is comparable in magnitude with the variation among the groups.     

Effects of selenium on growth and ultrastructure of the marine unicellular alga <Emphasis Type="Italic">Dunaliella salina</Emphasis> (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.     

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.     

Metal-Resistant Heterotrophic Bacteria in Coastal Waters of Primorye

Colony-forming heterotrophic bacteria were isolated from several locations in coastal waters of Primorye that differ in the extent and character of heavy metal pollution. Statistically significant differences in the minimum inhibitory concentrations of some metals were found for bacteria isolated from the environments with different levels of pollution. Bacterial strains that were highly tolerant of several heavy metals also showed resistance to a wide spectrum of antibiotics, and some strains bore plasmids of varying numbers and sizes. Bacteria of the family Enterobacteriaceae and the genus Pseudomonas were the dominant metal-resistant bacterial forms in the polluted coastal wasters of Primorye. No strict correlation was found between metal resistance and taxonomic identity of bacteria.Original Russian Text Copyright © 2005 by Biologiya Morya, Bezverbnaya, Buzoleva, Khristoforova.     

Recreational Effects in Vostok Bay, Sea of Japan

The paper presents the results of three hydrochemical surveys performed in October 2000 and May and July 2001 and microbiological monitoring performed in June, July, and August 2001 in Vostok Bay (Sea of Japan), which is a favorite recreation area for the inhabitants of Primorye and the Russian Far East. It is shown that at the height of recreation occurs during late summer, as determined by the concentration of water-dissolved oxygen, the biochemical oxygen demand (BOD₅), the concentration of detergents, and the number of colony-forming enterobacteria in 1 ml of water. However, in autumn, especially by October, the anthropogenic pressure decreases and the quality of the water environment in the bay improves.     

Effects of Desalination and the Detergent Sodium Dodecylsulphate on the Early Development of the Sand Dollar Scaphechinus mirabilis

We studied the effects of reduced water salinity on early ontogenesis in the sea urchin Scapechinus mirabilis. It is shown that the lower limit of salinity tolerance for the embryos and larvae is the salinity of 28. Under the mutual effects of desalination and sodium dodecylsulphate (SDS), an addition of 0.1 mg/l of the detergent to water with a salinity of 28 caused disturbances in the development of the larvae, starting from the stage of blastula. Desalination of the water down to 22 with the presence of SDS exerts significant effects already at the stage of fertilization. The mass death of embryos (73%) was observed at the stage of the first cleavage. The increase in the concentration of SDS up to 1 mg/l in water with a salinity of 28 to 22 caused an increase in the percentage of abnormal embryos and larvae from 40 up to 100%.     

Portable spectroscopic system for in vivo skin neoplasms diagnostics by Raman and autofluorescence analysis

The present paper studies the applicability of a portable cost‐effective spectroscopic system for the optical screening of skin tumors. in vivo studies of Raman scattering and autofluorescence (AF) of skin tumors with the 785 nm excitation laser in the near‐infrared region included malignant melanoma, basal cell carcinoma and various types of benign neoplasms. The efficiency of the portable system was evaluated by comparison with a highly sensitive spectroscopic system and with the diagnosis accuracy of a human oncologist. Partial least square analysis of Raman and AF spectra was performed; specificity and sensitivity of various skin oncological pathologies detection varied from 78.9% to 100%. Hundred percent accuracy of benign and malignant skin tumors differentiation is possible only with a combined analysis of Raman and AF signals.