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Finding of Paramecium dodecaurelia in Europe
Ewa Przybos1 and Sergei I. Fokin2
1 Department of Experimental Zoology, Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Krakow, Poland
2 Biological Research Institute, St. Petersburg State University, St. Petersburg, Russia
Summary
The presence of Paramecium dodecaurelia in Europe was recorded for the first time, in Italy (Elba Island) and Germany (Muenster).
Key words: distribution, Paramecium aurelia species complex, temperature barriers
Introduction
Paramecium dodecaurelia from the P. aurelia spp. complex was previously known only from the territory of the southern USA bordering on the Gulf of Mexico (Sonneborn, 1975), six strains were found there, namely: 246, 251, 270, 271, 273, and 274 (Sonneborn, 1974). Thus, the species had a rather limited range. Recently, the species has also been recorded in Japan, Honshu Island, Ube city (Przybos et al., 2003) and in Hawaii (Przybos and Fokin, 2003). Among 15 known species of the P. aurelia complex (Sonneborn, 1975; Aufderheide et al., 1983), P. dodecaurelia is a member of the group of species with the smallest cell size, along with P. tetraurelia, P. octaurelia, and P. decaurelia (cell length 120 mm). The paper presents new habitats of the species in Europe.
Material and methods
The strain designated GMS-1 was collected by H.-D. Gortz in 1998 in Germany, Muenster suburb. It has
bacterial endocytobionts belonging to Caedibacter sp. in the cytoplasm. The strain designated IEA1-8 was collected by S.I. Fokin in 1999 in Italy, Elbe Island, Azurro.
Culturing and identification of the strains were carried out according to Sonneborn’s methods (1970). The species was identified by mating the investigated reactive for conjugation clones with the mating types of the standard strains of known species of the P. aurelia spp. complex. The following standard strains were used: strain 90 of P. primaurelia, the Rieff strain, Scotland, of P. biaurelia, strain 324 of P. triaurelia, strain from Sydney, Australia, of P. tetraurelia, strain 87 of P. pentaurelia, strain 159 of P. sexaurelia, strain 325 of P. septaurelia, strain 138 of P. octaurelia, strain 510 of P. novaurelia, strain 223 of P. decaurelia, strain 219 of P. undecaurelia, strain 246 of P. dodecaurelia, strains 209 and 321 of P. tredecaurelia, strain 328 of P. quade-caurelia.
Autogamy was induced in daily isolated lines (Sonneborn, 1950) and its appearance was checked on the slides stained using acetocarmine.
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Paramecia were cultivated on a lettuce medium inoculated with Enterobacter aerogenes.
Results and discussion
The strains from Italy and Germany were identified as Paramecium dodecaurelia on the basis of 100% conjugation between the complementary mating types of the strains under examination with the corresponding ones of the strain 246 of P. dodecaurelia (from the southern USA).
No reaction was observed with the standard strains of the other species of the P. aurelia complex.
The viability of the offspring of the hybrid exconjugant clones of the inter-strain crosses (German strain x 246 strain from the southern USA and Italian strain x 246 strain) was observed in F1 obtained by conjugation and in F2 obtained by autogamy. A high viability was observed in F1 and in F2 generations.
Autogamy was observed in the strains after 15 fissions (the growth rate of culture was 3 fissions per day) in the daily isolated lines cultivated at 24oC. The strains studied are available in the Institute ofSystematics and Evolution of Animals (Department of Experimental Zoology), Polish Academy of Sciences, Krakow, Poland.
This is the first finding of P. dodecaurelia in Europe. Since species discrimination inside the P. aurelia complex is almost impossible without testing collection or RAPD-PCR technique, it is not so surprising that in many cases these species are still being recorded just as P. aurelia complex spp. In Europe, the most investigated area of the world, nine species of the P. aurelia complex have been found so far, i.e., P. primaurelia, P. biaurelia, P. triaurelia, P. tetraurelia, P. pentaurelia, P. sexaurelia, P. novaurelia, P. octaurelia, and P. tredecaurelia (Przybos and Fokin, 2000). P. novaurelia and P. biaurelia are the most common species in Europe (Przybos , 1998; Przybos and Fokin, 2000). Some other members of the complex seem to be true endemics and have never been found in Europe.
As Paramecium species have been the subject of investigation for over 250 years, it is very unlikely that
in Europe taxonomists could miss such well-noticeable ciliates as paramecia during checking of water samples. But for identification of even such «simple» ciliates as members of the Paramecium genus, protozoologist should have an adequate taxonomical knowledge. It is especially true in the case of the P. aurelia species complex. Expansion of the species list in the last decade shows that the zoogeographical status of some Paramecium species could be changed.
References
Aufderheide K.J., Daggett P.-M. and Nerad T.A. 1983. Paramecium sonneborni n. sp., a new member of the Paramecium aurelia species-complex. J. Protozool. 30, 128-131.
Przybos E. 1998. Frequency of species of the Paramecium aurelia complex in Europe. Folia biol. (Krakow). 43, 9-14.
Przybos E. and Fokin S.I. 2000. Data on the occurrence of species of the Paramecium aurelia complex world-wide. Protistology. 1, 179-184.
Przybos E. and Fokin S.I. 2003. Paramecium dodec-aurelia strains from Hawaii. Folia biol. (Krakow). 51, in press.
Przybos E., Fujishima M. and Nakaoka Y. 2003. Paramecium decaurelia and P. dodecaurelia from the P. aurelia spp. complex in Japan. Folia biol. (Krakow). 51, in press.
Sonneborn T.M. 1950. Methods in the general biology and genetics of Paramecium aurelia. J. Exp. Zool. 113, 87-148.
Sonneborn T.M. 1970. Methods in Paramecium research. In: Methods in Cell Physiology. (Ed. D.M. Prescott ). New York. 4, 242-339. Sonneborn T.M. 1974. Paramecium aurelia. In: Handbook of Genetics. (Ed. R.C. King ). New York. 2, 469-594.
Sonneborn T.M. 1975. The Paramecium aurelia complex of fourteen sibling species. Trans. Amer. Micros. Soc. 94, 155-178.
Address for correspondence: Ewa Przybos. Department of Experimental Zoology, Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Slawkowska 17, 31-016 Krakow, Poland. E-mail: przybos@isez.pan.krakow.pl
