Pollen profile Tegeler See, Brandenburg, Germany

The region D-s (Fig. 15.8) belongs to the Weichselian glaciated area of the North German lowlands and is a section of the older part of the young moraine landscape. The Warsaw-Berlin Urstromtal with the Spree River and the Havel lake-river system subdivide the region into four subregions, including a northern, southern and western ground moraine plateau. The region as a whole comprises the former West-Berlin, surrounded by the late GDR.

Pollen records of five sediment cores from northern Germany

Within a larger program research work is being done on the history of settlement and landscape of the 'Siedlungskammer' Flögeln and the adjacent area. The 'Siedlungskammer' consists of an isolated pleistocene sand ground (Geest-island) surroundet by bogs. Starting from the edge of the Geest, near which large-scale archaeological excavations are carried out, three raised bog profiles were taken at 300, 500 and 4000 m off the prehistoric settlement. They were investigated by means of pollen analysis, and reflect in a decreasing way the activities of man on the Geestisland. Another pollen diagram from the nearby fen peat was worked out for comparison. At the same time it helped to date back a prehistoric sand path to the Roman period. The pollen diagrams cover the vegetational history without gaps from the early Atlantic period to modern times. The vegetation was decisively determined by the poor soils of this area. T'he pollen diagrams give evidence of the activity of settlers since the Neolithic age, with some gaps in the beginning, but later continuously from the middle of the Bronze age until the early migration period. The influence of the nearby settlement, which existed from the Birth of Christ to the 4/5th century, comes out distinctly. Among the cereals which were then cultivated here, there also was rye, at least in the 4/5th century, but most probably already during the Roman period. Besides that people cultivated barley, oats, and flax. The settlement break during the so-called dark ages between the 4/5th century and the time about 800 A.D. was confirmed by pollen analysis. During this time the area was once more covered by forests. The fluctuations of man's activities during the late Middle Ages and modern times, as they are made visible by pollen analysis, correspond to historically wellknown developments.

New contributions to the native and alien flora in riparian habitats of the Cantabrian watershed (Northern Spain)

As a result of a floristic survey carried out in riparian habitats of northern Spain, new chorological data are provided for 9 alien and 6 native plant species. Some species are reported for the first time at regional scale, such as Carex strigosa, Helianthus x laetiflorus and Persicaria pensylvanica in Cantabria. Also noteworthy is the finding of naturalised populations of the North American grass Muhlenbergia schreberi at the Urumea river basin, which represents the second reference for the Iberian Peninsula.

Role of the Tryptophan Residues in the Specific interaction of the Sea Anemone Stichodacty la helianthus’s Actinoporin Sticholysin II with Biological Membranes

Actinoporins are pore-forming toxins from sea anemones. Upon interaction with sphingomyelin-containing bilayers, they become integral oligomeric membrane structures that form a pore. Sticholysin II from Stichodactyla helianthus contains five tryptophans located at strategic positions; its role has now been studied using different mutants. Results show that W43 and W115 play a eterminant role in maintaining the high thermostability of the protein, while W146 provides specific interactions for protomer−protomer assembly. W110 and W114 sustain the hydrophobic effect, which is one of the major driving forces for membrane binding in the presence of Chol. However, in its absence, additional interactions with sphingomyelin are required. These conclusions were confirmed with two sphingomyelin analogues, one of which had impaired hydrogen bonding properties. The results obtained support actinoporins’ Trp residues playing a major role in membrane recognition and binding, but their residues have an only minor influence on the diffusion and oligomerization steps needed to assemble a functional pore.