1062-3604/02/3304- $27.00 © 2002
Russian Journal of Developmental Biology, Vol. 33, No. 4, 2002, pp. 236–241. Translated from Ontogenez, Vol. 33, No. 4, 2002, pp. 285–291.
Original Russian Text Copyright © 2002 by Regerand, Nefedova, Toivonen, Dubrovina, Vuory, Markova, Ruokolainen.
Acidiﬁcation of natural water basins of the North
necessitates investigation of low pH inﬂuence on the
aquatic organisms. Our previous (Dubrovina
1991) and published data (Vinogradov
show that water acidiﬁcation is not only dangerous by
itself but also accompanies or induces disturbances
ecological homeostasis which are often irreversible.
For example, toxicity of several metal ions increased at
low pH (Mur and Ramamurty, 1987; Dubrovina
1994) and decreased resistance of the organisms to
them may cause a misbalance in functioning of the liv-
ing system (Linnik and Nabivanets, 1988).
Water pH depends on many factors including humus
content. In case of CO
equilibrium, pH of the surface
water in Karelia ranges from 4 to 8 (Lozovik, 1998).
Low values are speciﬁc for anthropogenically acidiﬁed
lakes or water enriched in humus. High values are com-
mon for light-coloured lakes. Acidiﬁcation of surface
water is a common anthropogenic disturbance. Acidic
atmospheric precipitation is typical for Karelia
(pH 4.1–6.5) (Lifshits
, 1992). The same problem
exists in Finland. Acidiﬁcation decreases water quality,
especially its applicability for ﬁsh breeding (Mark-
kanen and Ninioya, 1992).
Thus, it is very important to study the inﬂuence of
decreased pH on metabolism of aquatic invertebrates.
In this work we tried to estimate the role of lipids in
adaptation of the organisms to changed pH in the natu-
ral and artiﬁcial media.
MATERIALS AND METHODS
(phylum arthropods (Crustacea), class insects (Insecta),
order caddis (Trichoptera)) were used in the study.
They inhabit freshwater basins: streams, weed-infested
ponds, and littorals. Their shelter consists of a living
camera, capture net, and their vestibules. These organ-
isms constitute signiﬁcant part of feed supply for ben-
tophages including salmons and sturgeons.
Caddisﬂy larvae were trapped at the stone-covered
littoral of the Peilisjoky Lake near Kuhasalo (East Fin-
land) and acclimated to 16
C. Glass 100 ml ﬂasks were
used for the experiments.
Larvae were cultivated in the media with different
pH—6.0 (the control), 5.0 and 4.0—for 48 h. Lipid
composition of the larvae exposed to different pH and
trapped directly in the lake (lake water hereafter) were
compared. The standard salt solution for toxicological
experiments prepared with distilled water was used as
an artiﬁcial medium (colour index 0 degrees). Natural
water was taken from the Peilisjoky Lake (colour index
The samples prepared from 300–500 mg of larvae
were used for the biochemical analyses. Larvae were
homogenized in chloroform/methanol medium (2 : 1, v/v)
in the presence of antioxidant ionol (0.001%), diluted
10 times with the solvent and stored in the cold. Lipids
were extracted after Folch
(1957). Lipids were
fractionated in Silufol plates in the mixture of petro-
leum ether:ethyl ether:acetic acid (90 : 10 : 1). Pphos-
Lipid Metabolism of Caddisfly Larvae at Low pH
T. I. Regerand*, Z. A. Nefedova**, L. T. Toivonen**, L. V. Dubrovina*, K.-M. Vuory***,
L. V. Markova**, and T. R. Ruokolainen**
*Institute of Aquatic Problems of the North, Karel Scientiﬁc Center of the Russian Academy of Sciences,
pr. A. Nevskogo 20, Petrozavodsk, 185003 Russia
**Institute of Biology, Karel Scientiﬁc Center of the Russian Academy of Sciences,
Pushkinskaya ul. 11, Petrozavodsk, 185610 Russia
***Center of the Environment of North Karelia, Joensuu, 80101 Finland
Received August 3, 2000; in ﬁnal form, January 11, 2001
—The inﬂuence of low pH (5.0 and 4.0) on lipid metabolism of caddisﬂy larvae
L. (Trichoptera) was studied in 48 h toxicity experiments. The results were correlated with lipid com-
position of caddisﬂy larvae directly isolated from natural water. Phospholipids, cholesterol, mono-, di-, tria-
cylglycerols, and fatty acids were detected by thin-layer and liquid chromatography. Minimal environmental
changes were shown to initiate the biochemical adaptation mechanisms strengthening the cellular membranes
through their condensation due to additional phospholipid and cholesterol synthesis. In the natural medium the
adaptation processes are more active than in the artiﬁcial medium. More serious changes, such as pH decrease
to 4.0, suppress the adaptation processes in the ﬁrst medium and terminate them in the second one.
: early ontogenesis, water invertebrates, lipid metabolism, lipids, pH.