The Role of non-NMDA-Receptors in the Process of Associative Learning in the Honeybee Apis mellifera

Pharmacological parameters of non-NMDA-receptors and their participation in the associative learning in the honeybee Apis mellifera L. have been studied using the method of conditional reflexes and pharmacological analysis. The effect of 1-amino-3-hydroxy-5-methyl, 4-isoxazolprpionate (AMPA), kainate, domoate, antagonist of AMPA-receptors NS-257 HCl and modulator of AMPA-receptors cyclothiazide was studied on retention of the elaborated conditional reflex in short- and long-term memory. It was shown that AMPA-receptors, but not kainate receptors, are involved in the process of formation of short-term memory and are characterized by pharmacological profile similar with that in molluscs. Coactivation of AMPA- and NMDA-receptors is considered as one of possible mechanisms of formation of short-term memory in the honeybee.     

The influence of diet on the duration and thermal sensitivity of development in the linden bug Pyrrhocoris apterus L. (Heteroptera: Pyrrhocoridae)

Temperature and nutrition are crucial environmental variables that determine rates of growth and development in insects. However, the simultaneous effect of these factors on life‐history traits is rarely addressed. In the present study, the influence of two diets (linden fruit and sunflower seeds) on the duration of immature stages and thermal reaction norms for development is tested in the bug Pyrrhocoris apterus L. (Heteroptera: Pyrrhocoridae). Eggs and larvae are reared at five constant temperatures (20, 22, 24, 26 and 28 °C) under an LD 20 : 4 h photocycle. Development rates deviate from linearity in the studied thermal range, especially in larvae; therefore, a nonlinear (power‐law) approximation is also attempted. Parental diet causes no change in thermal reaction norms for egg development. However, the progeny of sunflower‐fed bugs are more variable in terms of their development time, suggesting a transgenerational effect. Larval mortality rates increase in cooler conditions and are always higher on sunflower seeds. This is accompanied by more variable, less temperature‐dependent and generally slower larval development. A review of previously published case studies on temperature–diet interactions in the control of insect development leads to two general conclusions. First, there are two approaches for assessing the temperature‐dependent development in insects: one based on the concept of the sum of degree‐days and the other based on the concept of reaction norm. Despite an obvious non‐exclusiveness, the two approaches appear to have developed in isolation from each other. Second, three principal patterns of temperature–diet interactions can be recognized. The pattern found in P. apterus (the direct effects of diet are stronger at higher temperatures and much weaker or absent at lower temperatures) appears to be the most widespread.     

On heterogeneity of DNA methylases from Escherichia coli SK cells

Summary The presence ofE. coli SK cells of five different DNA-methylases differing in specificity to the methylated sequence is documented has been proven. Two enzymes methylate cytosine with the formation of 5′-methylcytosine and three enzymes methylate adenine with formation of 6′-methylaminopurine. A method for simultaneous isolation of the five individual enzymes including gel filtration on Biogel A-0.5 M is proposed. The direct evidence has been presented showing that the additional methylation test in our method modification actually can discriminate between enzymes differing in sensitive sites.     

Behavior of subadult mountain voles of two species (<Emphasis Type="Italic">Alticola strelzowi</Emphasis> and <Emphasis Type="Italic">A. tuvinicus</Emphasis>) in the open field test

A comparative study of mobility and anxiety of subadult flat-headed and Tuva silver voles in an open field test has been performed using arenas 50 and 63 cm in diameter. It is found that individuals of both species demonstrate higher movement speed and cover longer distances, both on the periphery and in general, on the larger arena. Interspecies behavioral differences have been identified only in the arena 63 cm in diameter. Subadult flat-headed voles demonstrate higher mobility and lower anxiety in the test compared to Tuva silver voles. Hypotheses pertaining to specific features of the ecology of the two species reflected in their behavior are proposed.     

The action of befol and its derivatives on monoamine oxidase of different origins

The effect on deamination of serotonine, dopamine, tiramine and 2-phenylamine of benzamide derivatives befol, moclobemide and LIS-641 was studied. Befol and moclobemide are inhibitors of serotonine deaminating activity of MAO. The different sensitivity of this activity to the effect of the benzamide derivatives in beef or rat brain and human placenta was noted. The inhibition was more distinct in tissue homogenate than in corresponding mitochondrial fractions.