Effect of oil-pollution of water on delayed fluorescence of the algae <Emphasis Type="Italic">Chlorella vulgaris</Emphasis> Beijer and survival rate of the cladoceran <Emphasis Type="Italic">Daphnia magna</Emphasis> Str.

The paper gives the results of the laboratory experiments on the influence of different concentrations of oil in water environment over the chlorella and daphnia. It is shown that as the oil content in water increases, the intensity of delayed fluorescence of test-culture of chlorella and the survival rate of the daphnia decrease. However, for the chlorella the decrease in fluorescence as the indicator of its photosynthetic activity is observed only at very high concentrations of oil (1000–2000 MPC), whereas the survival rate of the cladocerans begins to drop at 4 MPC. A similar dependence is observed when sunflower-seed oil is introduced into the environment as an imitator of the oil pollution. We suppose that the negative influence of oil over the microalgae and cladocerans is conditioned more by the physical factors than by chemical ones.     

Heterocyst Structure Alteration and O2-Mediated Inhibition of Dinitrogen Fixation by Trichlorfon in Anabaena PCC 7119

The involvement of a primary inhibition of dinitrogen fixationin the toxic effect of trichlorfon in cyanobacteria has beeninvestigated. Significant inhibition of nitrogenase activitycan be detected 3 h after the addition of insecticide to batchcultures of Anabaena PCC 7119. Recovery of nitrogenase activitystarts between 6–12 h after removal of the insecticide,suggesting a requirement for the induction of new heterocysts.Under anaerobic conditions the inhibitory effect of the insecticideis largely prevented. Biochemical analysis indicates that envelopeglycolipids exist in trichlorfon-treated cultures. However,ultrastructural examination shows heterocyst deterioration andthe failure of the inner glycolipid layer of the heterocystenvelope. Our data are consistent with the view that destabilizationof the heterocyst envelope is the first target of insecticidalaction. Inhibition of dinitrogen fixation and growth have alsobeen shown in the cyanobacteria Gloeothece PCC 6501, NostocUAM 205, and Chlorogloeopsis PCC 6912.     

Fermentation of inositol by bacteria of the genus Salmonella

The capacity for the fermentation of inositol varies in different Salmonella strains. At the same time this capacity forms the basis for the determination of biovars (e. g., in S. typhimurium) and sometimes serves as the only sign for distinguishing different Salmonella sero- and biovars (e. g., S. mission and S. isangi, etc.). The study of the capacity of wild Salmonella strains for the fermentation of inositol has revealed that the fermentation of inositol is controlled by chromosomal and, seemingly, plasmid genes. In the latter case the possibility of using this sign for the biochemical and epidemiological typing of Salmonella strains is questionable.     

External structure of postorbital organ of certain representatives of family astronesthidae (Stomiiformes)

The external structure of postorbital organ is described in detail in seven representatives of family Astronesthidae, i.e., Borostomias elucens, B. panamensis, B. mononema, B. antarcticus, Heterophorus ophistoma, Neonesthes microcephalus, and Rhadinesthes decimus. The shape, sizes, position with respect to eye, and some other features of the structure of the postorbital organ are characteristic of the species or close species. The comparison of the structure of this organ in the above-mentioned representatives of the family Astronesthidae and earlier studied species of genus Astronesthes is given.