Isolation and characteristics of antibodies against synthetic fragments of oncoproteins. II. Antiserum against the transforming protein pp60src of Rous sarcoma virus

To generate the antibodies to the transforming protein of Rous sarcoma virus (RSV) pp60src, rabbits were immunized with the peptide, corresponding to 415-421 sequence of pp60src. These antibodies immunoprecipitate pp60src in RSV-transformed chicken and mammalian cells, and also some proteins (45, 85 and 120 kDa), which could be autophosphorylated in vitro. It was shown that 415-421 sequence of pp60src is not recognized by the antibodies to pp60src from RSV-induced tumour bearing rabbits (TBR serum). In contrast to TBR serum, antibodies, generated against synthetic peptide, corresponding 415-421 sequence of pp60src couldn't be phosphorylated in vitro, when [gamma-32P]ATP is added to the immune complex. The antipeptide antibodies, bound to pp60src did not block phosphorylation of TBR immunoglobulins, added to this immune complex. Hence, 415-421 sequence of pp60src RSV containing the major tyrosine phosphorylation site does not take part in the kinase reaction in vitro.     

Interaction of viral and cellular genes in cervical tumors

The results obtained in the Laboratory of Molecular Biology of Viruses, CRC carried out in the framework of the Human Genome program and devoted to the study of the activity of cell and viral genes in cervical cancer are summarized. DNA of human papillomaviruses persists in tumors both in episomal and integrative forms. Integration may occur in different regions of chromosomes. Viral transforming genes E6 and E7 are always present in tumor cells, while antibodies to these proteins are detected only in approximately 30% of patients. Loss of heterozygosity is detected on long and short arms of chromosome 6; some such cases are manifest already at the early stages of tumor progression, while others are typical of the late stages. Several genes that are potentially involved in tumorigenesis and are subject to hypermethylation in CpG islands were identified. Methylation of several genes is observed in approximately 30% of tumors. Tumor progression is associated with increased expression of p16ink4a, an inhibitor of cyclin-dependent kinases.     

The antidepressant-like effect of Ocimum basilicum in an animal model of depression

We investigated the efficacy of Ocimum basilicum (OB) essential oils for treating depression related behavioral, biochemical and histopathological changes caused by exposure to chronic unpredictable mild stress (CUMS) in mice and to explore the mechanism underlying the pathology. Male albino mice were divided into four groups: controls; CUMS; CUMS plus fluoxetine, the antidepressant administered for pharmacological validation of OB; and CUMS plus OB. Behavioral tests included the forced swim test (FST), elevated plus-maze (EPM) and the open ?eld test (OFT); these tests were performed at the end of the experiment. We assessed serum corticosterone level, protein, gene and immunoexpression of brain-derived neurotropic factor (BDNF) and glucocorticoid receptors (GRs) as well as immunoexpression of glial fibrillary acidic protein (GFAP), Ki67, caspase-3 in the hippocampus. CUMS caused depression in the mice as evidenced by prolonged immobility in the FST, prolonged time spent in the open arms during the EPM test and reduction of open field activity in the OFT. OB ameliorated the CUMS induced depressive status. OB significantly reduced the corticosterone level and up-regulated protein and gene expressions of BDNF and GR. OB reduced CUMS induced hippocampal neuron atrophy and apoptosis, and increased the number of the astrocytes and new nerve cells. OB significantly increased GFAP-positive cells as well as BDNF and GR immunoexpression in the hippocampus.     

Interaction between Viral and Cell Genes in Cervical Tumors

The results of the works carried out in the Laboratory of Molecular Biology of Viruses, CRC in the framework of the Human Genome program and devoted to the study of the activity of cell and viral genes in cervical cancer are summarized. DNA of human papillomaviruses persists in tumors both in episomal and integrated forms. Integration may occur in different regions of chromosomes. Viral transforming genes 6 and 7 are always present in tumor cells, while antibodies to these proteins are detected only in 30% of patients. Loss of heterozygosity is detected on the long and short arms of chromosome 6; some such cases are manifest already at the early stages of tumor progression, while others are typical of the late stages. A number of cell genes potentially involved in tumorigenesis are shown to be hypermethylated in CpG islands. Methylation of several genes at once is observed in 30% of tumors. Tumor progression is associated with increased expression of 16 ^ink4a, an inhibitor of cyclin-dependent kinases.     

Productivity of forests in the Eurosiberian boreal region and their potential to act as a carbon sink –- a synthesis

Based on review and original data, this synthesis investigates carbon pools and fluxes of Siberian and European forests (600 and 300 million ha, respectively). We examine the productivity of ecosystems, expressed as positive rate when the amount of carbon in the ecosystem increases, while (following micrometeorological convention) downward fluxes from the atmosphere to the vegetation (NEE = Net Ecosystem Exchange) are expressed as negative numbers. Productivity parameters are Net Primary Productivity (NPP=whole plant growth), Net Ecosystem Productivity (NEP = CO₂ assimilation minus ecosystem respiration), and Net Biome Productivity (NBP = NEP minus carbon losses through disturbances bypassing respiration, e.g. by fire and logging). Based on chronosequence studies and national forestry statistics we estimate a low average NPP for boreal forests in Siberia: 123 gC m^–2 y^–1. This contrasts with a similar calculation for Europe which suggests a much higher average NPP of 460 gC m^–2 y^–1 for the forests there. Despite a smaller area, European forests have a higher total NPP than Siberia (1.2–1.6 vs. 0.6–0.9 × 10¹⁵ gC region^–1 y^–1). This arises as a consequence of differences in growing season length, climate and nutrition. For a chronosequence of Pinus sylvestris stands studied in central Siberia during summer, NEE was most negative in a 67-y old stand regenerating after fire (– 192 mmol m^–2 d^–1) which is close to NEE in a cultivated forest of Germany (– 210 mmol m^–2 d^–1). Considerable net ecosystem CO₂-uptake was also measured in Siberia in 200- and 215-y old stands (NEE:174 and – 63 mmol m^–2 d^–1) while NEP of 7- and 13-y old logging areas were close to the ecosystem compensation point. Two Siberian bogs and a bog in European Russia were also significant carbon sinks (– 102 to – 104 mmol m^–2 d^–1). Integrated over a growing season (June to September) we measured a total growing season NEE of – 14 mol m^–2 summer^–1 (– 168 gC m^–2 summer^–1) in a 200-y Siberian pine stand and – 5 mol m^–2 summer^–1 (– 60 gC m^–2 summer^–1) in Siberian and European Russian bogs. By contrast, over the same period, a spruce forest in European Russia was a carbon source to the atmosphere of (NEE: + 7 mol m^–2 summer^–1 = + 84 gC m^–2 summer^–1). Two years after a windthrow in European Russia, with all trees being uplifted and few successional species, lost 16 mol C m^–2 to the atmosphere over a 3-month in summer, compared to the cumulative NEE over a growing season in a German forest of – 15.5 mol m^–2 summer^–1 (– 186 gC m^–2 summer^–1; European flux network annual averaged – 205 gC m^–2 y^–1). Differences in CO₂-exchange rates coincided with differences in the Bowen ratio, with logging areas partitioning most incoming radiation into sensible heat whereas bogs partitioned most into evaporation (latent heat). Effects of these different surface energy exchanges on local climate (convective storms and fires) and comparisons with the Canadian BOREAS experiment are discussed. Following a classification of disturbances and their effects on ecosystem carbon balances, fire and logging are discussed as the main processes causing carbon losses that bypass heterotrophic respiration in Siberia. Following two approaches, NBP was estimated to be only about 13–16 mmol m^–2 y^–1 for Siberia. It may reach 67 mmol m^–2 y^–1 in North America, and about 140–400 mmol m^–2 y^–1 in Scandinavia. We conclude that fire speeds up the carbon cycle, but that it results also in long-term carbon sequestration by charcoal formation. For at least 14 years after logging, regrowth forests remain net sources of CO₂ to the atmosphere. This has important implications regarding the effects of Siberian forest management on atmospheric concentrations. For many years after logging has taken place, regrowth forests remain weaker sinks for atmospheric CO₂ than are nearby old-growth forests.     

Isolation and characteristics of antibodies against synthetic fragments of oncoproteins. I. Antiserum against the transforming protein p28sis of simian sarcoma virus

To generate the antibodies to the transforming protein (p28sis) of simian sarcoma virus (SSV), the rabbits were immunized with peptides, corresponding to 200-206 and 201-210 sequences of p28sis, conjugated with protein carriers by different ways. The synthesis of peptides was carried out by the classical techniques in solution by using the benzyl type side protecting groups. Antibody titres against peptides were determined by ELISA and protein specificity by radioimmunoprecipitation and immunoblotting. It was shown that the antibodies to 201-210 peptide recognize p28sis and its dimer p56sis in marmoset and rat cells transformed by simian sarcoma virus.