1021-4437/02/4902- $27.00 © 2002
Russian Journal of Plant Physiology, Vol. 49, No. 2, 2002, pp. 235–241. Translated from Fiziologiya Rastenii, Vol. 49, No. 2, 2002, pp. 264–271.
Original Russian Text Copyright © 2002 by Pronina, Kovshova, Popova, Lapin, Alekseeva, Baum, Mishina, Tsoglin.
Nontraditional sources of vitamins, fatty acids,
essential amino acids,
-carotene, etc. are essential sup-
plements to food and feed in many cases. Unicellular
photosynthetics can be used as such a source [1–3].
One of the most perspective organisms among them is
cyanobacterium (blue-green alga)
The preference of this organism was revealed during a
comparative analysis of a great scope of microalgae [1,
is used as a valuable food and vitamin
complement to food for people and animals, because its
biomass is enriched with valuable proteins, vitamins,
and fatty acids.
The plasticity of microalgal metabolism provides
additional possibilities for regulating their biomass
quality by directed changes in growth conditions [5, 6].
This approach turned out to be particularly useful for
biomass enriched with microele-
ments [7–9]. Selenium is especially promising. When
incorporated from plants into the food chain of man or
animal, selenium plays a substantial role in certain met-
abolic functions, and its deﬁciency destroys the latter.
The biological role of selenium depends, ﬁrst of all, on
its being a constituent of glutathion peroxidase partici-
pating in animal and plant cell protection from the per-
oxidation and tyramine deiodinase responsible for the
synthesis of thyroid hormones in animal organisms [10,
11]. Production of preparations with a high content of
biologically available forms of Se-containing organic
compounds is an important problem for some regions
of Russia where deﬁciency of selenium content in tra-
ditional food is responsible for the development of car-
dio-vascular and cancerous diseases, necroses, cata-
racts, and so on [11–13].
In order to produce a biomass enriched with sele-
nium, the following investigation had to be carried out:
(1) screen the range of possible Se-salt concentrations
in the cultural medium, (2) detect the cell components
accumulating Se and estimate the changes in the ratio
of organic to inorganic Se-containing compounds in
dependence on the microelement concentration in the
medium; and (3) study the content of main cell compo-
nents (protein, lipids, carbohydrates, and pigments) in
the cells grown at the raised microelement concentra-
tion in the medium.
In order to perform the ﬁrst task, it was necessary to
determine, ﬁrst of all, the highest concentration of
exogenous selenium that would not inhibit the growth
The Effect of Selenite Ions on Growth and Selenium
N. A. Pronina*, Yu. I. Kovshova*, V. V. Popova*, A. B. Lapin**, S. G. Alekseeva**,
R. F. Baum***, I. M. Mishina**, and L. N. Tsoglin*
*Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya ul. 35, Moscow, 127276 Russia;
fax: 7 (095) 977-8018; e-mail: email@example.com
**Lomonosov State Academy of Fine Chemical Technology, Moscow
***Joint Stock Company “Spetsial’noe mashinostroenie i metalurgiya plus,” Moscow
Received July 13, 2001
—Selenium accumulation and the growth of cyanobacterium
(Nordst.) Geitl. were
studied in a culture with sodium selenite-supplemented nutritional medium. Selenite concentrations below
20 mg/l did not inhibit the growth of
The addition of 30 mg/l of this salt somewhat decreased the
growth rate during the linear growth phase, induced the earlier suspension transition to the steady-state phase,
and substantially lowered the highest optical density of the suspension. However, even at 170 mg/l Na
the culture still demonstrated a capacity for growth. The content of selenium in the cells depended directly on
its concentration in the medium, up to the lethal level. At high selenium concentrations (100–170 mg/l),
reduced Se(IV) up to Se(0). The latter was secreted onto the cell surface and into the cultural medium.
The high concentrations of Na
acidiﬁed the cytoplasmic pH as was measured by
At the same time, the content of protein on a dry weight basis decreased and that of carbohydrates and lipids
somewhat increased, just as was observed in
cells under other stress factors. In the presence of
20 mg/l Na
, the selenium content in the biomass increased by 20000 times as compared to that in the con-
trol cells, whereas the biochemical composition of biomass did not change. In this case, the selenium was incor-
porated almost completely in the protein fraction. The selenium concentration in this fraction increased more
signiﬁcantly when the sulfur content was lowered in the medium.
Key words: Spirulina platensis - growth - sodium selenite - selenium accumulation - sulfur