The expression of the prolactin receptor (PRL-R) gene has been investigated in various tissues of tilapia (Oreochromis niloticus) reared in fresh or brackish water. Using a cDNA probe spanning the extracellular domain of the tilapia PRL-R and Northern blot analysis, the presence of tilapia PRL-R mRNA has been confirmed in the osmoregulatory organs and has been detected in other tissues, includi...

The history of the Middle East has been influenced by past global climatic changes. Warm periods caused droughts, resulting in desertification, migration and war. Cold periods were humid and brought prosperity and agricultural settlement to the desert fringes. The forecast based on this correlation is that the present global warming will cause the drying up of the Middle East. As in the past, t...

Lakes Nicaragua and Managua are large, rather shallow, fresh-water bodies that lie in a late Tertiary and Quaternary graben in western Nicaragua. The bottom sediments comprise highly organic diatomaceous volcanic silts and clays in which quartz plagioclase feldspar, dioctahedral montmorillonite and volcanic glass are the principal constituents. ' Organic nitrogen content of the lake sediments r...

Three-spined stickleback (Gasterosteus aculeatus L.), nine-spined stickleback (Pungitius pungitius (L.)) and flounder (Platichthys flesus (L.)) are widespread teleosts, which all have behaviours involving migration between freshwater and brackish/sea water environments. Their importance in dispersal of the freshwater monogenean Gyrodactylus salaris Malmberg, 1957, which causes heavy losses of A...

BACKGROUND AND AIMS The mid-Cretaceous is a period of sudden turnover from gymnosperm to angiosperm-dominated floras. The aim was to investigate the fossil plant ecology in order to follow the spread of angiosperm taxa. METHODS Floristic lists and localities from the latest Albian-Cenomanian of Europe are analysed with Wagner's Parsimony Method, a clustering method currently used in phylogeny...

In an earlier paper (Lockwood, 1961) it was shown that the brackish-water amphipod, Gammarus duebeni, begins to form urine hypotonic to the blood about 2 hr. after the animal is transferred from a highly concentrated medium (100-175% sea water) to fresh water. The osmotic concentration of the blood at the time the urine first becomes hypotonic may be as much as 1 M./l. NaCl, a value twice as hi...

A unique example of brackish water fjord-related diversification of a new nudibranch genus and species Bohuslania matsmichaeli gen. n., sp. n. is presented. There are only few previously known brackish-water opisthobranchs and B. matsmichaeli gen. n., sp. n. is the first ever described brackish-water nudibranch with such an extremely limited known geographical range and apparently strict adhere...