Long term effects of Chernobyl contamination on DNA repair function and plant resistance to different biotic and abiotic stress factors

Thirty years after the Chernobyl explosion we still lack information regarding the genetic effects of radionuclide contamination on the plant population. For example, are plants adapting to the low dose of chronic ionising irradiation and showing improved resistance to radiation damage? Are they coping with changing/increased pathogenicity of fungi and viruses in the Chernobyl exclusion (ChE) zone? Are plant populations rapidly accumulating mutational load and should we expect rapid micro-evolutionary changes in plants in the Chernobyl area? This review will try to summarise the current knowledge on these aspects of plant genetics and ecology and draw conclusions on the importance of further studies in the area around Chernobyl.     

Dry Heat Inactivation of Bacillus subtilis var. niger Spores as a Function of Relative Humidity

Dry heat sterilization of Bacillus subtilis var. niger spores at 105 C is enhanced in the relative humidity range 0.03 to 0.2%. D-values of 115 and 125 C are predicted by a kinetic model with parameters set from 105 C data. These predictions are compared to observations.     

Description of eight phases of spermiogenesis in the marmoset testis

The differentiation of spermatids in the marmoset (Callithrix jacchus, n = 9) testis is described here at the light-microscopic level employing serial semithin sections. The definition of 8 different phases of spermiogenesis, i.e. the formation of spermatids, is based upon the changes in the development of nucleus, acrosome and flagellum.     

Enhancement of α-lactalbumin-like activity in mammary explants from pregnant rats in the absence of exogenous prolactin

Mammary explants from pregnant rats showed a progressive increase in α-lactalbumin activity during culture with insulin, hydrocortisone and prolactin. Unexpectedly, culture with only insulin and hydrocortisone produced a similar rate of increase of α-lactalbumin-like activity, but this increase commenced about 24 hr later. The delay suggests that the enhanced activity effected by insulin and hydrocortisone is not a reflection of carry-over of endogenous mammotrophic hormones. Insulin plus hydrocortisone did not stimulate casein or fatty acid synthesis by pregnancy tissue, and did not enhance α-lactalbumin-like activity in virgin rat mammary explants. Enhancement of this activity by insulin plus hydrocortisone in pregnant tissue was constant over a wide range of glucocorticoid concentrations, but was inhibited by progesterone. Available evidence indicates that the active factor in extracts from insulin-hydrocortisone-explants is a heat-stable protein which is either α-lactalbumin itself, or another molecule with similar specifier properties.     

Population structure,dispersal and colonization history of the garden bumblebee <Emphasis Type="Italic">Bombus hortorum</Emphasis> in the Western Isles of Scotland

New methods of analysing genetic data provide powerful tools for quantifying dispersal patterns and reconstructing population histories. Here we examine the population structure of the bumblebee Bombus hortorum in a model island system, the Western Isles of Scotland, using microsatellite markers. Following declines in other species, B. hortorum is the only remaining long-tongued bumblebee species found in much of Europe, and thus it is of particular ecological importance. Our data suggest that populations of B. hortorum in western Scotland exist as distinct genetic clusters occupying groups of nearby islands. Population structuring was higher than for other bumblebee species which have previously been studied in this same island group (F_st = 0.16). Populations showed significant isolation by distance. This relationship was greatly improved by using circuit theory to allow dispersal rates to differ over different landscape features; as we would predict, sea appears to provide far higher resistance to dispersal than land. Incorporating bathymetry data improved the fit of the model further; populations separated by shallow seas are more genetically similar than those separated by deeper seas. We argue that this probably reflects events following the last ice age when the islands were first colonized by this bee species (8,500–5,000 ybp), when the sea levels were lower and islands separated by shallow channels would have been joined. In the absence of significant gene flow these genetic clusters appear to have since diverged over the following 5,000 years and arguably may now represent locally adapted races, some occurring on single islands.     

Development of a diagnostic test system for detecting soluble staphylococcal antigens by an immunoenzyme method

ELISA is used for detecting the soluble staphylococcal antigen in patients with purulent septic infections. The optimum conditions for the assay have been established: the dose of staphylococcal gamma globulin for plate sensitization should be 5.0-10.0 micrograms/ml, the pH of the buffer solution 9.6-10.0, the time and temperature of incubation 18-20 hours at 4 degrees C or 5 hours at 37 degrees C. The possibility of using plates manufactured in the USSR has been shown. The sensitivity of the above diagnostic test system is 0.005 microgram/ml.