Complementation in somatic hybrids indicates four types of nitrate reductase deficient lines in Nicotiana plumbaginifolia

Summary Allelism of nine nitrate reductase deficient (NR^–) Nicotiana plumbaginifolia cell lines was tested by complementation after protoplast fusion. Complementation was recognized by the appearance of somatic hybrid colonies growing on a selective NH₄ ⁺/NO₃ ^– medium which cannot support the growth of NR^– lines. All five apoenzyme defective (NA) lines were non-complementing and therefore allelic. The apoenzyme and the cofactor defective (NX) lines were complementing, as expected, and gave somatic hybrids with restored nitrate reductase activity. The four cofactor defective lines were found to belong to three complementation groups (NX1 and NX9; NX21; NX24). Two of these (NX21 and NX24) are of new types which have not been previously described in flowering plants. In the somatic hybrids restoration of NR activity was accompanied by the restoration of plant regeneration ability. On leave from: Instituto di Mutagenesi e Differenziamento CNR, Via Svezia, 10, 56100, Pisa, Italy     

Localization of proteins forming the outer surface of isolated metaphase chromosomes.

The outer surface of isolated metaphase chromosomes has been investigated by a method of thermally activated tritium labelling. We show that both chromosomal proteins and DNA are tritium-labelled. Fractionation of the chromosomal proteins reveals that scaffold proteins are the most labelled in condensed and EDTA-decondensed chromosomes. Exposition of some scaffold proteins on the outer surface of metaphase chromosomes is suggested.     

Rabies of wild mammals in Russia at the turn of the 20th and 21st centuries

Analysis of the incidence of animal rabies in Russia (1960–2006) and assessment of the abundance of wild canids and rabies infection prevalence among them (1981–2006) have been made. The results provide evidence for the dominant role of red foxes in the spread of rabies among wild animals (91.67%), which is confirmed by a strong correlation between the abundance of this predator and the numbers of infected animals (r = 0.73). In 2004 to 2006, the prevailing incidence of animal rabies in one or another territory was determined mainly (74.7%) by the pooled population density of red and corsac foxes and wolves. Natural and economic features of the landscape determined the incidence of rabies indirectly, via changes in the numbers of wild animals (by 68.9%). A comparative analysis of the recorded and potentially possible rabies incidence rates among wolves, red and corsac foxes, and raccoon dogs over the period from 1996 and 2006 is presented.     

An experience of rearing some hawk moths (Lepidoptera,Sphingidae) on artificial diets

A method for rearing five hawk moth species, namely Acherontia atropos (Linnaeus, 1758), A. lachesis (Fabricius, 1798), Agrius convolvuli (Linnaeus, 1758), Daphnis nerii (Linnaeus, 1758), and Hyles livornica (Esper, 1780) (Lepidoptera, Sphingidae) on artificial diets is described. Two recipes of these artificial rearing media are proposed. Special attention is given to maintenance of adult moths in captivity and raising immature stages.     

The effect of starvation on taste preferences and testing behavior of food items in the carp <Emphasis Type="Italic">Cyprinus carpio</Emphasis>

The present study is aimed at recording changes in taste preferences and behavior related to testing of artificial agar-agar (2%) pellets with free amino acids (21 amino acids, L-isomers, 0.1–0.001 M) in the carp Cyprinus carpio at increasing duration of starvation (2, 12, 18, 24, 72, and 144 h). Two hours after the end of feeding until satiation, the fish manifest a low foraging activity and, in most cases, they do not grasp the offered pellet. Later on, the feeding motivation in fish increases rapidly and up to 24 h of starvation each of the offered pellets is grasped. In the first hours of starvation the fish refuse from consumption of the grasped pellets even with highly attractive taste stimuli (extract of chironomids, cysteine). Up to 24 h of starvation, the fish restore the differentiated attitude to taste properties of amino acids. Of the latter, four amino acids increase, six decrease, and the other 11 do not render significant influence on consumption of pellets. Up to 72 h of starvation, at the background of continuing increase in the absolute level of consumption of pellets of all types, the taste preferences change but weakly. However, up to 144 h of starvation the number of deterrent amino acids was reduced to one (phenylalanine). At increasing duration of starvation, the number of repeated grasping of pellets changes weakly while duration of testing by fish of pellets of most types increases, especially abruptly in the first 24 h. It is assumed that the decrease or complete loss in fish of the negative reaction to substances, initially having aversive taste properties may be considered as the main mechanism providing expansion of the feeding spectrum and/or transfer of fish onto consumption of new items, initially consumed just occasionally or fully avoided.     

New data on the trout Salvelinus leucomaenis and its relationships with Dolly Varden trout S. malma curilis in fresh waters of the southern Kuril Islands

The biology, structure of populations, and morphology of diadromous East Siberian char Salvelinus leucomaenis from two rivers of the Kuril Islands—the Kunashir and the Iturup—are studied and the resident lacustrine form from Lake Peschanoe is described for the first time. It is shown that the specific features of the anadromous migration of diadromous individuals, the relative numbers of juveniles of the trout Salvelinus leucomaenis, and the rate of their growth are determined by the temperature dynamics and the sizes of the freshwater water bodies used for spawning.