[The distribution of bacterioplankton and mesozooplankton biomass in the White and Barents Seas coastal water]. / Osobennosti rasprostraneniia bakterio- i mezozooplanktona v pribrezhnykh vodakh Belogo i Barentseva morei.

The total population density and the biomass of bacterioplankton, mesozooplankton, and phosphate-accumulating bacteria (PAB) were estimated during the 2000-2001 summer-autumn seasons in the coastal waters of the White and Barents Seas, which are subjects to the action of tidal and sea currents, the inflow of riverine waters, and anthropogenic impact. In the shallow estuarine waters with salinities of 6.5-32@1000 near the Chernaya, Pesha, and Pechora River mouths, the population of PAB fluctuated from 0.1 to 9.1 million cells/ml (0-36% of the total bacterial population). In pelagic seawaters, which are low in phosphates (12-50 micrograms/l) and are characterized by an increased iron/phosphorus ratio (2.0-3.6), bacterioplankton amounted to 0.1-1.6 million cells/ml and was mainly represented by small organisms with a volume of 0.08-0.15 micron 3, commonly lacking intracellular polyphosphates. In the pelagic zone of the Barents Sea, the biomass of mesozooplankton (Bz) was comparable with that of bacterioplankton (Bb = 39-175 mg/m3), the Bb/Bz ratio being 1.4-4.6. Off the Varandeiskii, Pechora, and Kolguyev oil terminals, Bb increased to 155-300 mg/m3 and the Bb/Bz ratio rose to 1.4 to 50.3 (with an average value of 20.9), presumably due to the severe anthropogenic impact on these waters. In this case, the dense population of bacterioplankton (0.9-7.6 million cells/ml) was mainly represented by large cells (0.12-0.76 micron 3 in volume), most of which (3-43% of the total bacterioplankton population) contained polyphosphates. The chemical composition of these waters was characterized by an elevated content of the total phosphorus (65-128 micrograms/l) and by a low iron/phosphorus ratio (0.9-1.2).

[Intracellular accumulation of monomer precursors of polyphosphates and polyhydroxyalkanoates from Acinetobacter calcoaceticus and Escherichia coli]. / Vnutrikletochnoe kontsentrirovanie monomernykh predshestvennikov polifosfatov i poligidroksialkanoatov Acinetobacter calcoaceticus i Escherichia coli.

The formation of polyhydroxyalkanoates granules in anaerobically grown Escherichia coli cells was found to be preceded by the intracellular accumulation of carbonic acids (predominantly, acetic acid), amounting to 9% of the cytosol. The intracellular concentration of acidic metabolites increased after the lyophilization of the bacterial biomass and decreased after its long-term storage (3.5-13.5 years). The decrease in the concentration of acidic metabolites is likely due to the dehydration of dimeric carbonic acids in the viscoelastic cytosol of resting bacterial cells. The hydrophobic obligately aerobic cells of Acinetobacter calcoaceticus IEGM 549 are able to utilize a wide range of growth substrates (from acetate and citrate to hydrophobic hydrocarbons), which is considerably wider than the range of the growth substrates of E. coli (predominantly, carbohydrates). The minimal essential and optimal concentrations of orthophosphates in the growth medium of A. calcoaceticus were found to be tens of times lower than in the case of E. coli. The intracellular content of orthophosphates in A. calcoaceticus cells reached 35-77% of the total phosphorus content (Ptotal), providing for the intense synthesis of polyphosphates. The Ptotal of the A. calcoaceticus cells grown in media with different proportions between the concentrations of acetate and phosphorus varied from 0.7 to 3.3%, averaging 2%. This value of Ptotal is about two times higher than that observed for fermenting E. coli cells. Lowering the cultivation temperature of A. calcoaceticus from 37-32 to 4 degrees C augmented the accumulation of orthophosphates in the cytoplasm, presumably owing to a decreased requirement of growth processes for orthophosphate. In this case, if the concentration of phosphates in the cultivation medium was low, they were completely depleted.