Changes in the selfexcitation reaction in rats under the effect of modulated electromagnetic field]

The effect of electromagnetic field with various modulation frequencies (2, 7, and 50 hertz) on the reaction of selfstimulation was studied in rats. The frequency of 2 hertz proved to cause a primary increase in the incidence of the selstimulation reaction, followed by its depression; the frequency 7 hertz at first failed to alter the selfstimulation intensity and then led to the gradual reduction of the incidence of the selfstimulation reaction; the frequency of 50 hertz depressed the selfstimulation reaction practically from the very beginning. The changes in the selfstimulation reaction were independent of the localization of the stimulating electrodes, but were determined by the frequency of the EMF modulation.     

High velocity mechanical injection of foreign DNA into fish oocytes

High-velocity tungsten microprojectiles were used to introduce into fertilized eggs of loach (Misgurnus fossilis), Rainbow trout (Salmo gairdneri Rich.) and Zebra fish (Brachydanio rerio) DNA sequences of beta-galactosidase and neomycin phosphotransferase genes. No more than 30% of fish oocytes died as a result of bombardment. Experiments revealed marked activity of both enzymes in developing fishes. Neo gene DNA sequences were found in total danio DNA using PCR technique.     

Proliferation of the exocrine and endocrine portions of the pancreas after its resection]

A weak regenerative capacity of the pancreas was revealed after the resection of about 40 per cent of the tissue of this organ in mice-hybrids CBA X C57BL/6, weighing 20--28 g. During the 21 days of the experiment there was no significant restoration of the pancreas weight. An increase of the proliferative activity (the number of mitoses and daily fraction of the thymidine-3H-labeled cells were counted) was brief and failed to spread over the whole organ. The maximal number of the labeled nuclei in the epithelium of the acini and the islets was found in the area near the wound where the organ tissue was somewhat edematous. In the areas near the wound surface, but unaffected, the labeled cells count was increased during the early post-operative period only. The number of labeled cells of the islets and acini of the pancreas in the areas distant from the wound (in the loop of the duodenum) was no different from the control. The number of labeled cells in the islets was greater than in the acini.     

Empirical evidence of the mediterranean fruit fly movement between orchard types

Understanding species movement in the agroecological system is an important theme in ecology. A mark–release–capture experiment was conducted to study the dispersion behaviour of the Mediterranean fruit fly, Ceratitis capitata (Wied.; Diptera: Tephritidae; Medfly) in northern Israel. Four pairs of pear and citrus orchards were selected for the field experiments. Sterile flies dyed with different colours were released in three seasons during 2015 and 2016, based on the phenological stages of the hosts. The total number of captured marked sterile flies per trap (FT) was approx 300 in both April and August. In November, FT values decreased by about 35% to approximately 200. The wild Medfly that were also captured showed an opposite trend, from an FT of 1.8 and 6.4 in April and August, respectively, to an FT of about 330 in November. Marked sterile flies were captured in both the release and the neighbouring orchard sites. We found that the Medfly migrates from pear to citrus orchards during spring and from citrus to pear during summer, when there are no fruit-bearing trees in the orchards. However, during November, when the wild Medfly population prevails in the area, a clear pattern of migration is hard to identify, perhaps because of a possible interaction with the wild fly's population.