Osm druhů vodních měkkýšů bylo transportováno s rostlinami na korkových rolích ke zpevňování břehů ze severozápadního Polska (Tucholská oblast, povodí Visly) do Prahy při rekonstrukci jedné vodní nádrže. Jiný zajímavý případ představuje zavlečení druhu Bithynia troschelii pravděpodobně s vodními rostlinami do záchranného centra v Botanickém ústavu AV ČR v Třeboni. Přesný původ těchto plžů není znám, ale pravděpodobné se jeví Neziderské jezero v rakousko-maďarském pohraničí, odkud pocházejí některé pěstované rostliny. Pravděpodobně z tohoto zdroje se následně dotyčný vzácný plž dostal i na některá další místa v České republice. and Eight species from a site in the north-western part of Poland (Tuchola region, Wisla/Vistula River Basin) were transported on coir rollers and matting which were used for the stabilisation of the reservoir banks during a water reservoir restoration in Prague. In the other example, Bithynia troschelii was probably transported with aquatic plants to the Institute of Botany, Academy of Sciences of the Czech Republic Třeboň (South Bohemia). The origin of the individuals has not been known out of doubt, but it is possible that they originate from the Neusiedler Lake on the Austrian-Hungarian border since some cultivated plants.
In both embryonal carcinoma (EC) and embryonic stem (ES) cells, the differentiation pathway entered after treatment with retinoic acid (RA) varies as it is based upon different conditions of culture. This study employs mouse EC cells P19 to investigate the effects of serum on RA-induced neural differentiation occurring in a simplified monolayer
culture. Cell morphology and expression of lineage-specific molecular markers document that, while non-neural cell types arise after treatment with RA under serum-containing conditions, in chemically defined serum-free media RA induces massive neural differentiation in concentrations of 10-9 M and higher. Moreover, not only neural (Mash-1) and
neuroectodermal (Pax-6), but also endodermal (GATA-4, α-fetoprotein) genes are expressed at early stages of differentiation driven by RA under serum-free conditions. Furthermore, as determined by the luciferase reporter assay, the presence or absence of the serum does not affect the activity of the retinoic acid response element (RARE). Thus, mouse EC cells are able to produce neural cells upon exposure to RA even without culture in three-dimensional embryoid bodies (EBs). However, in contrast to standard EBs-involving protocol(s), neural differentiation in monolayer
only takes place when complex signaling from serum factors is avoided. This simple and efficient strategy is proposed to serve as a basis for neurodifferentiation studies in vitro.