Liposomes as carriers of polyfunctional immunogens

Liposomes are promising carriers for construction of the up-to-date chemical vaccinal preparations. The immunogenic and immunomodulating properties of liposomes may be varied by incorporation of the natural or synthetic immunomodulators into the inner water volume or into the lipid bilayer parallel with antigens as well as by introduction of the receptor-specific vector to definite types of immunocompetent cells into liposomes. The pronounced immunobiological properties of the liposomal carrier are shown in studies of liposomes conjugated with haptens or model protein antigens. The application of liposomes as carriers of bacterial antigens induces a delayed catabolism of the antigen and formation of its depot. The immunomodulating properties of antigen-containing liposomes rise after introduction of such immunomodulators as lipid A, muramyldipeptide or interleukin-1 into the liposome composition.     

The estimation of the amount of diphtheria toxin and its activity by various tests in the dynamic cultivation of Corynebacterium diphtheriae PW8]

Direct correlation between the results of tests for the biological activity of diphtheria toxin, carried out in vivo guinea pigs and in vitro in the microcytotoxicity test in CHO cell culture, has been established, which makes it possible to use the latter as one of the methods for the rapid, reproducible and economic evaluation of diphtheria toxin. The qualitative and quantitative evaluation of diphtheria toxin in the enzyme immunoassay with the use of monoclonal antibodies and in the microcytotoxicity test demonstrates that these two tests, when used for controlling cultivation processes, have essential advantages over the flocculation test as regards their specificity and information content.     

Experimental study of the temperature effect on survival and development rates in the early ontogenesis of common toad (Bufo bufo)

The influence of temperature on mortality and development rate of common toad Bufo bufo was investigated in the laboratory conditions. It was shown that the rate of embryogenesis at +19°C increased almost 1.4 times as compared with the development of a temperature of +15°C. The temperature affects the resulting embryo mortality at the time of hatching primarily in clutches with low survival.     

Penicillium chrysogenum mycelial productivity in the 1st phase of penicillin biosynthesis]

The course of the mycelium low productivity during the first phase of the usual two-stage process of penicillin biosynthesis was studied. It was found that the low productivity of the mycelium at the beginning of the fermentation process was probably associated with catabolic regression of the penicillin-producing system. The high specific growth rate registered in the experiments (0.06-0.08 hours-1) had no negative effect on the mycelium productivity. It was not possible to connect the productivity level with the mycelium age, because young and mature mycelium had the same producitivity levels at any developmental stage under the same conditions.     

Spring phenology in boreal Eurasia over a nearly century time scale

It has been widely reported that tree leaves have tended to appear earlier in many regions of the northern hemisphere in the last few decades, reflecting climate warming. Satellite observations revealed an 8-day advance in leaf appearance date between 1982 and 1991 in northern latitudes. In situ observations show that leaf appearance dates in Europe have advanced by an average of 6.3 days from 1959 to 1996. Modelling of leaf appearance on the basis of temperature also shows a marked advance in temperate and boreal regions from 1955 to 2002. However, before 1955, reported studies of phenological variations are restricted to local scale. Modelling, ground observations and satellite observations are here combined to analyse phenological variations in Eurasian taiga over nearly a century. The trend observed by remote sensing consists mainly in a shift at the end of the 1980s, reflecting a shift in winter and spring temperature. In western boreal Eurasia, a trend to earlier leaf appearance is evident since the mid-1930s, although it is discontinuous. In contrast, the strong advance in leaf appearance detected over Central Siberia using satellite data in 1982–1991 is strengthened by late springs in 1983–1984; moreover, in this region the green-up timing has displayed successive trends with opposite signs since 1920. Thus, such strong trend is not unusual if considered locally. However, the recent advance is unique in simultaneously affecting most of the Eurasian taiga, the leaf appearance dates after 1990 being the earliest in nearly a century in most of the area.