Role of Polyamine-Induced Dimerization of Antizyme in Its Cellular Functions

Funding: This work was supported by grants from the Russian Science Foundation (grant # 17-74-20049—synthesis of C-methylated Spd analogues, ITC studies of dimerization of OAZ1, and frameshifting experiments), the Russian Science Foundation (grant # 19-74-10086—isolation of OAZ1, electrophoresis studies of dimerization of OAZ1), and the Academy of Finland (grants # 292574 and # 315487). Acknowledgments: The authors thank A. Karppinen, A. Korhonen, T. Reponen, M. Salminkoski, and S.D. Negrya for their skillful technical assistance.Peer reviewedPublisher PD

Bidirectional fluxes of spermine across the mitochondrial membrane.

The polyamine spermine is transported into the mitochondrial matrix by an electrophoretic mechanism having as driving force the negative electrical membrane potential (DW). The presence of phosphate increases spermine uptake by reducingDpH and enhancingDW. The transport system is a specific uniporter constituted by a protein channel exhibiting two asymmetric energy barriers with the spermine binding site located in the energy well between the two barriers. Although spermine transport is electrophoretic in origin, its accumulation does not follow the Nernst equation for the presence of an efflux pathway. Spermine efflux may be induced by different agents, such as FCCP, antimycin A and mersalyl, able to completely or partially reduce theDWvalue and, consequently, suppress or weaken the force necessary to maintain spermine in the matrix. However this efflux may also take place in normal conditions when the electrophoretic accumulation of the polycationic polyamine induces a sufficient drop inDWable to trigger the efflux pathway. The release of the polyamine is most probably electroneutral in origin and can take place in exchange with protons or in symport with phosphate anion. The activity of both the uptake and efflux pathways induces a continuous cycling of spermine across the mitochondrial membrane, the rate of which may be prominent in imposing the concentrations of spermine in the inner and outer compartment. Thus, this event has a significant role on mitochondrial permeability transition modulation and consequently on the triggering of intrinsic apoptosis

On the early Flandrian stratigraphy and vegetational history of the North Satakunta area, western Finland

The stratigraphical sequence of two till beds with varved clay between them has been described from the North Satakunta area. The position of this sequence in geochronology has been compared with the retreat process of the ice in southern Finland. It has been suggested that the sequence is early Flandrian in age and it seems to show a corresponding climatic rhythm as can be seen from the pollen stratigraphy of north-western Europe (Ostfriesland, Germany) during the Pre-Boreal period. The early Flandrian vegetational history of the North Satakunta area shows the open plant communities on the emerged dry land of the archipelago character. During the regression of the Yoldia Sea and after pollen zone transition IV/V the forest expanded rapidly in the area studied

Chemostratigraphy of the Holocene sediments of Lake Työtjärvi in southern Finland and its limnological significance

The significance of some chemical elements during the limnological history of Työtjärvi, a small oligohumic lake in southern Finland, is discussed. Sedimentary chlorophyll, organic matter, phosphorus, iron, manganese, magnesium, aluminium, zinc, copper, sodium, potassium and calcium were determined from the sediment core investigated, and their stratigraphical distribution was interpreted in terms of limnology. Sodium, potassium, aluminium, magnesium and, possibly also, calcium can be used as indicators of the intensity of erosion during the developmental history of Lake Työtjärvi, especially since the first signs of land use in the catchment of the lake. In contrast, the sedimentary chlorophyll, phosphorus and Fe/Mn ratio throw light on the typological development of Lake Työtjärvi, adding more details to earlier biostratigraphical results. By applying the trophic terminology it can be concluded that Lake Työtjärvi was eutrophic in its early stages during the Preboreal and Boreal periods, but that it rapidly became increasingly dys-oligotrophic at the beginning of the Atlantic period as a result of the ombrotrophic development in the adjacent bog, Varrassuo. The eutrophication associated with prehistoric land use in the catchment was the second conspicuous change in the limnological history of Lake Työtjärvi. It was not, however, continuous, and the lake remained dys-oligotrophic. The most recent change in the limnology of the lake has been the fall of the water colour, probably due to acid precipitation of anthropogenic origin

Radiocarbon ages from the bottom deposits of Lake Sarkkilanjärvi, south-western Finland

A contribution to the Post-Pleistocene (= Holocene) chronology of south-western Finland, based on pollen stratigraphy and C14-datings, has been presented in this paper. Five sites were compared with the Central Scanian (southern Sweden) sequence at Ageröd mosse dated in detail with radiocarbon method. The results show that the zone boundaries V/VI and VIII/IX seem to be synchronous in the area investigated, whereas T0, P0 and P+ are time transgressive and only reflect local successions

Holocene lacustrine microfossils and environmental changes

This review is concerned with the biostratigraphical use of the lacustrine microfossils such as diatoms, blue-green and green algae, Mallomonadaceae, Cladocera and larval insect remains preserved in lake sediments and their value as bioindicators of Holocene environmental changes in Finland. From lake sediment studies discussed in the text it can be concluded that the lacustrine microfossils are useful for the reconstruction of typological and waterlevel changes in lakes, catchment conditions and climatic fluctuations. They can also give profitable information for examing the cultural eutrophication and acidification of lakes. In the light of the microfossil studies the most significant natural development of Finnish lakes has been a typological succession from the mineroeutrophic (argillotrophic or pelotrophic) state towards more dysoligotrophic conditions. This meiotrophication process is strictly related to the influence of environmental humic substances on the limnology of lakes. To analyze microfossils is still the most important key for the characterization of lacustrine environments during the Holocene