Implementing the water framework directive in Bulgaria: Integrated river basin management on the Black Sea coast.

EC member states and candidate countries are in the process of implementing the requirements of the EC Water Framework Directive 2000/60, which came into force on 22 December 2000. At the core of the Directive is an integrated approach for sustainable water management in river basin districts. The overall objective is to reach good water status for all waters by the year 2015. The challenges for countries implementing the Directive are substantial not least for the River Basin Management Authorities who will be the implementing unit at the regional level. The Black Sea River Basin Directorate in Varna is one of four Directorates established in Bulgaria in 2002 in accordance with the Bulgarian Water Act and is the regional operational unit under the Ministry of Environment and Water for the Black Sea Basin catchment area. The catchment area covers 20% of Bulgaria and 100% of the Bulgarian Black Sea coast. Current implementation activities in the Black Sea Basin Directorate and also at the national level are supported by the Danish EPA through its DANCEE programme in collaboration with the Ministry of Environment and Water. This paper highlights the main activities and outputs of the technical and institutional undertakings in the Black Sea Basin Directorate focusing on the preparation of the River Basin Overview by Dec. 2004.

Changes in the neuronal plasma membrane during synaptogenesis.

During synaptogenesis the plasma membrane of neurons undergoes considerable changes and large portions of it develop to synaptic membranes. This transformation is brought about by biochemical and morphological changes. The aim of the present investigation was to study by morphological methods the in vivo changes of some basic components of the neuronal membranes during the early postnatal period, when active synaptogenesis occurs. The cerebral cortex of Wistar rats was used for preparation of either growth cones (up to postnatal day 10) or synaptosomes (postnatal days 14-30). Our studies were focused on the changes occurring in integral membrane proteins and cholesterol domains, and in certain carbohydrate residues and anionic sites. In the first days after birth relatively few intramembranous particles are found in the plasma membranes of growth cones, few and small cholesterol domains, scarce lectin-binding and anionic sites. During the following days there is a clear tendency for increase of the number of all of the studied structures until the appearance of typical synaptic membranes. Throughout the studied developmental period the protein and the cholesterol molecules were found to occupy distinct membrane domains. The structure of the developing neuronal membrane, poor on proteins and cholesterol, and its maturation to the fully functional synaptic membrane is discussed.

Light and electron microscopic demonstration of cholesterol distribution in membrane structures of the rat auditory cortex.

As part of our investigations on the changes in the cortex of different stages of ontogeny, the aim of this study was to analyse the cholesterol distribution in the auditory cortex of adult rats. The light microscopic Schultz reaction as well as electron microscopic thin sections and freeze-etching combined with a cholesterol specific marker were applied to cholesterol demonstration. High and low cholesterol areas were found in the plasma membrane and membranes of some organelles. A low cholesterol content was observed in the membranes of the Golgi apparatus, mitochondria and junctional contacts. A very low cholesterol content was found in the pre- and postsynaptic membranes. High cholesterol contents were present in the neuronal and glial non-junctional plasma membranes. The cholesterol distribution in the membranes of the endoplasmic reticulum and nuclear envelope appeared to be different.