A filamentous freshwater cyanobacteriuni, identifíed as Oscillatoria annae, has two different phycoerythrins. One of them contains only phycoerythrobilin chromophores, thus being a typical C-phycoerythrin. The other has both phycoerythrobilin and phycourobilin chromophores and is therefore related to CU- phycoerythrins (cyanobacterial phycoerythrins containing urobilin). The stoichiometry of the chromophore prosthetic groups in CU-phycoerythrin from O. annae is 1:1, therefore the (ap)-polypeptide monomer of this phycoerythrin carries three phycoerythrobilin and three phycourobilin prosthetic groups. The pigment is believed to be a new t3T)e of CU-phycoerythrin.
Salinization is an increasing enviromental problem in ecosystems. The assessment of total dissolved solids (TDS), pH, electrical conductivity (EC), exchangeable sodium percentage (ESP), alkalinity and the concentrations of main ions makes possible to identify salinization and alkalization degree. The saltaffected soils occur in the south part and south-east part of Žitný ostrov, where the dry and mild summer climate, evaporation soil water regime and mineralized groundwater create conditions for development of the saline and alkaline soils. Five localities with highly-mineralized groundwater were monitored to evaluate salinity and alkality in the period 1989-2006. At the bottom horizons in localities 1 - 5 evaporative residues (salt content) reached value 0.1 - 0.2 %. In 2006 dry evaporative residues (salt content) was higher than 0.2 %, EC was higher than 250 mS m-1 at the bottom horizons in localities 1, 2, 4. The mentioned data allow us to state that salinization and alkalization of soils is developing, it starts from the bottom of soil horizons through middle part of the soil profile up to the top horizons. This phenomenon was observed in all investigated soils in different stages of development. and Salinizácia v ekosystémoch je stále významnejší enviromentálny problém. Stanovenie celkového množstva rozpustených látok (TDS), elektrickej vodivosti (EC), sodíkového adsorpčného pomeru (SAR) a obsahu výmenného sodíka (ESP) umožňuje identifikáciu kritického potenciálu salinizácie a degradácie pôdy. Záujmové územie bolo vymedzené vo východnej časti Žitného ostrova, kde suché a horúce klimatické podmienky spolu s vysokomineralizovanými podzemnými vodami sú príčinou translokácie solí do pôdneho profilu. Bolo monitorovaných 5 lokalít v období 1989 - 2006. Namerané údaje poukazujú na vzrastajúci obsah solí, ktorý v r. 2006 dosiahol 0,1 - 0,2 % v celom pôdnom profile vo všetkých monitorovaných lokalitách, hodnoty EC 200 - 400 mS m-1 v spodných horizontoch vytvárajú podmienky pre rozvoj zasolených pôd.
The fine structure of the oviduct, oviduct-uterine junction and uterus of the nematode Toxocara canis (Werner, 1782) is described. Columnar-type epithelioid cells with numerous microvilli at the apical membrane border the oviduct lumen. Many electron dense secretory products are present in these cells. The cells lining the oviduct-uterine junction have no microvilli. They are coated with an electron-dense layer and contain numerous membrane-bound dense material containing bodies. Externally, the cells are surrounded by a basal lamina and muscle cells. The epithelial cells lining the greater part of the paired uteri appear to be rather flat. The oocytes inside the oviduct are covered with a dense thick plasma membrane and contain lipid droplets, dense granules and glycogen. The morphology of the oocytes before the fertilization inside the oviduct-uterine junction resembles that of the oocyte in the oviduct. After the fertilization the egg shell formation takes place. The egg shell of T.canis is composed of four layers: uterine, vitelline, middle chitinous and inner layer. The differences between the fine structure of the egg shell of T. canis and other related nematodes are discussed.