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The retroelement Penelope isolated from Drosophila virilis has a very unusual structure and codes for reverse transcriptase and an endonuclease belonging to the UvrC type. As shown previously,Penelope is a key element in induction of the hybrid dysgenesis syndrome described in D. virilis, which also involves mobilization of several unrelated mobile element families. Here we report a successful introduction of Penelope into the D. melanogaster genome by P element-mediated transformation. In the new host genome,Penelope is actively transcribed producing major transcript which coincides with that detected in dysgenic hybrids of D. virilis. In situ hybridization on D. melanogaster polytene chromosomes and Southern blotting revealed multiple transpositions of Penelopein the transformed D. melanogaster strains. We determined the structure of six Penelope copies inserted into D. melanogaster chromosomes. Some transformed D. melanogaster strains showed dysgenesis effects similar to those observed in hybrids from D. virilis dysgenic crosses.

The mobile element Penelopeis activated and mobilizes several other transposons in dysgenic crosses in Drosophila virilis. Its structure proved to be complex and to vary greatly in all examined species of the virilisgroup. Phylogenetic analysis of the reverse transcriptase (RT) domain assigned Penelopeto a new branch, rather than to any known family, of LTR-lacking retroelements. Amino acid sequence analysis showed that the C-terminal domain of the Penelopepolyprotein is an active endonuclease, which is related to intron-encoded endonucleases and to bacterial repair endonuclease UrvC, and may act as an integrase. Retroelements coding for a putative endonuclease that differs from typical integrase have not been known thus far. Phylogenetic analysis divided the Penelopecopies from several virilisspecies into two subfamilies, one including virtually identical full-length copies, and the other comprising highly divergent defective copies. The results suggest both vertical and horizontal transfer of the element. Possibly, Penelopeinvasion recurred during evolution and contributed to genome rearrangement in the virilisspecies. Chromosome aberrations detected in D. virilis, which is now being invaded by Penelope, is direct evidence for this assumption.

TheDrosophila virilis Delta (Dl) gene was localized and cloned. Sequencing and sequence analysis of its 3′ fragment revealed a 83% homology between its deduced product andD. melanogaster Delta. Northern hybridization revealed four major transcripts ofD. virilis Dl. In situ hybridization to whole embryos showed that the temporal and spatialDl expression patterns are much the same inD. virilis andD. melanogaster.

Spontaneously hypertensive rats (SHR) display several features of the human insulin-resistance syndromes. Cd36 deficiency is genetically linked to insulin resistance in SHR. We show that transgenic expression of Cd36 in SHR ameliorates insulin resistance and lowers serum fatty acids. Our results provide direct evidence that Cd36 deficiency can promote defective insulin action and disordered fatty-acid metabolism in spontaneous hypertension.

Isolated tobacco (Nicotiana tabacum L.) microspores maturing in vitro can be induced to undergo symmetrical divisions, instead of the normal asymmetrical first pollen mitosis, by addition of anther extracts to the culture medium. The two daughter cells in symmetrically divided pollen resemble vegetative pollen cells in cytological characteristics, nuclear size and chromatin condensation, are separated by a cell wall and remain viable during in vitro maturation. After transfer to a germination medium, only one of the two vegetativelike cells forms a pollen tube in vitro. Therefore, apparently normal gametophytic development can be maintained after symmetrical microspore division. These results are discussed in relation to current models for induction of microspore embryogenesis.

1. On the basis of an analysis of the experimental adsorption isotherms of benzene, determined within a broad range of temperatures, the minimum volume of experimental data required for a reliable determination of the parameters of the microporous structure was determined. 2. For adsorbents with monodisperse structure, it is sufficient to have one isotherm at 20°. For adsorbents containing two varieties of micropores, it is necessary to obtain two adsorption isotherms at temperatures 20 and 80–100°.

1. It has been shown that in the case of single-stage and multi-stage adsorbers the concentrations of an impurity in the gaseous or solid phase during continuous adsorption and desorption can be calculated from the equations for the material and thermal balance. 2. The method of fastest discharge has been used for solving the problem of continuous adsorption and desorption in a fluidized bed with a nonlinear adsorption isotherm. 3. The results of theoretical calculations are compared with those for an experiment on adsorption of methane in a single-stage and a multi-stage adsorber. 4. A program has been compiled for solving the problem with a BESM-2 computer.

1. On the basis of an analysis of the dynamics of adsorption in a system of parallel transport with a variable coefficient of internal mass exchange, a method of machine calculation of the effluent curve and time of protective action, using the Shilov equation, was proposed. 2. The results obtained were compared with the experimental data on the dynamics of the adsorption of benzene on activated charcoal. The coincidence of the calculation and experimental data was quite satisfactory.

1. The additivity of the coefficients of external and internal mass exchange within a broad range of variation of the Biot criterion was demonstrated on the basis of a theoretical analysis and calculations on a BESM-2 digital computer. 2. An empirical equation was obtained for determining the coefficient of internal mass exchange in the case of a linear adsorption isotherm. 3. The coefficients of internal diffusion and internal mass exchange were compared on the basis of experimental data on the kinetics of the adsorption of benzene on activated charcoals.

1. A method of calculating the surface of transitional pores on a digital computer has been proposed which is based on the representation of the experimental data of the desorption branch of the capillary condensation curve in the form of a polynomial by the method of least squares. 2. The results of the computer calculation have been compared with the values of the surface of connecting pores obtained by the graphical method.

1. Owing to the efficient mixing of the solid phase and the high rate of mass exchange, the component concentrations in a fluidized bed are practically equal to the equilibrium values. 2. The authors compile and solve a system of differential equations for the dynamics of continuous adsorption in a fluidized bed. 3. It is shown that the concentrations of the components in the gas and solid phases in one- and multi-stage adsorbers can be calculated from the sorption isotherm equations and the equation of mass balance. 4. The theoretical relations thus obtained are compared with experimental results for the adsorption of methane in one- and multi-stage adsorbers.