The usage of marker traits in plants for evaluation of resistance of the winter wheat to pest insects

A new method of selection of the winter wheat varieties has been tested for resistance to the pest insects' complex by the traits of plants that are the markers of plant resistance. It makes it possible to use this method from year to year independently of the pests' density.     

Blood testosterone in rats: correlation with individual anxiety and its derangement after the "death threat"

After preliminary testing on a multiparameter scale, test and experimental groups of Wistar male rats were formed on the principle of identical distribution of individuals with different anxiety levels. A negative Spearman correlation between the testosterone blood concentration and the level of anxiety was observed in intact rats: the minimum hormonal concentrations (lower than 5 nmol/l) were found in rats with high anxiety, whereas the maximum concentrations (up to 16 nmol/l) corresponded to the higher anxiety level (prevalence of passive defense reactions during testing). After a sort-term exposure to life-threatening situation (viewing of a boa's attacking and devouring two victim rats from the test group), the correlation was deranged because of appearance of a scatter in testosterone blood concentration (from 3 to 21 nmol/l) in rats with low anxiety. Neurotization with inescapable pain stimulation also deranged the initial anxiety-testosterone correlation, but, as distinct from the exposure to life-threatening situation, eliminated individual differences in testosterone concentration at its low level. The results suggest the existence of multiple ways of adaptation to life-threatening situations in a rat population.     

Development of passivity in the rat: effect of tranquilizers and antidepressants

Following the views on passivity as one of the features of depression-like behaviour in rats developing as a result of unavoidable painful stimulation an attempt was made to eliminate by antidepressant drugs the passivity manifested in an almost complete absence of motor searching reactions in an "open field" and a maze. However tranquilizing drugs rather than antidepressants to a greater extent induced the effect presupposed. Hence the type of passivity under study corresponds more likely to neurotized behaviour than to a special depression-like. In the second series of experiments the action was studied of multiple injections of antidepressants on similar manifestations of passivity as well as on alimentary instrumental conditioned responses in rats with initially expressed passive character of behaviour. In this case too neither the presupposed increase of motor searching reaction was observed nor any significant changes in the rate of instrumental conditioning nor elimination of its failures of a "refuse" type.     

Type of behavior and superoxide dismutase activity in the brain of rats (a comparison of 2 Tryon strains)

Differences in the type of behaviour in capable ("maze-bright") and incapable ("maze-dull") Tryon rats have been demonstrated in the situation with pain-irritated partner by the method of "emotional resonance". Most "bright" rats belonged to the type not avoiding the signals of another pain-irritated rat, they revealed a persistent ecologically defensive reaction of preferring a small closed space. The type of anxiety behaviour prevailed in the group of "dull" rats. In the open field test "bright" rats were characterized by low locomotor activity and high level of defecation and "dull" rats by high activity and low defecation. Increased levels of superoxide dismutase activity and high content of thiobarbituric acid-reactive material were observed in brains of dull rats. The interrelations between behavioural and molecular levels of defensive response to stress is discussed.     

A comparison of the take of embryonic amygdala and visual cortex transplants in the rat brain in connection with the possible compensation of functional disorders]

Transplantation of embryonic (E17-18) visual cortex and amygdala was performed into corresponding damaged areas of the adult rat brain. It was shown in Nissl and Golgi preparations (by comparing qualitative and quantitative findings) that 2-6 months after operation the grafts were successful in case of putting them into the corresponding brain areas (cortex to cortex, or amygdala to amygdala). Graft's integration resulted in a selective increase of dendrite length and ramification towards the area of graft-host interface both in amygdala and visual cortex grafts. In case of inadequate graft-host integration the stratification of the grafted visual cortex could be observed. The structural reorganization of grafted neurones is compared with physiological and behavioural findings during the recovery processes in damaged brain.     

Can the function of the extirpated amygdaloid complex be compensated for by the transplantation of embryonic nerve tissue?

In 20 white rats bilateral coagulation of the amygdalar complex was produced; on the fifth day to one half of them transplantation was performed by introducing stereotaxically on the left side 0.2-0.5 mm3 of the brain embryonal tissue from the corresponding area of the amygdala of 20-days embryo; in control saline was administered. After two months the rats were sacrificed to determine the activity of antiradical defense by superoxide dismutase (SOD) and the level of lipids peroxide oxidation (LPO) in the cerebral cortex. The transplantation decreased LPO even more and increased SOD as compared to amygdalectomy, e. i. caused still greater deviations from the norm (in this meaning--paradoxal effect), what apparently corresponds to intensification of adaptative-compensatory processes caused by amygdalectomy. The transplantation did not reverse the rats behaviour to the initial one and did not eliminate memory defect in the test of conditioned reaction of passive avoidance (like pyrazetam); it had different direction influence on "drinking under current" in conflict situation, only in particular cases approaching it to the norm.     

Dendritic structure in neurons of embryo amygdala grafts

Brain preparations stained by Golgi's technique in grafts of rat embryo basolateral amygdaloid nucleus were transplanted into the intact brain and the cavity produced by electrolytic destruction of the adult rat amygdala, revealing two types of neurons — sparsely and densely arborizing cells. It was found from comparing grafted with intact units that length and arborization of the cell had increased in sparsely arborizing cells after grafting, whereas the cell body had decreased in size and dendrites lengthened in densely arborizing units; neuronal arborization had also increased considerably. It was found from analyzing polar histograms of dendritic density distribution that neurites of transplanted neurons are selectively orientated depending on the area where the graft has united with the host brain. Altered neuronal geometry is assumed to be a factor determining the graft's ability to contribute to compensatory functions of the lesioned brain.Institute of Higher Nervous Activity and Neurophysiology, Academy of Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 22, No. 5, pp. 579–586, September–October, 1990.     

Distribution of transfer RNA genes in thePisum sativum chloroplast DNA

Purified chloroplast tRNAs were isolated fromPisum sativum leaves and radioactively labeled at their 3′ end using tRNA nucleotidyl transferase and α³²P-labeled CTP. Pea ctDNA was fragmented using a number of restriction endonucleases and hybridized with thein vitro labeled chloroplast tRNAs by DNA transfer method. Genes for tRNAs have been found to be dispersed throughout the chloroplast genome. A closer analysis of the several hybrid regions using recombinant DNA plasmids have shown that tRNA genes are localized in the chloroplast genome in both single and multiple arrangements. Two dimensional gel electrophoresis of total ct tRNA have identified 36 spots. All of them have been found to hybridize withPisum sativum ctDNA. Using recombinant clones, 30 of the tRNA spots have been mapped inPisum sativum ctDNA.     

Revealing pancrustacean relationships: Phylogenetic analysis of ribosomal protein genes places Collembola (springtails) in a monophyletic Hexapoda and reinforces the discrepancy between mitochondrial and nuclear DNA markers

Background  

In recent years, several new hypotheses on phylogenetic relations among arthropods have been proposed on the basis of DNA sequences. One of the challenged hypotheses is the monophyly of hexapods. This discussion originated from analyses based on mitochondrial DNA datasets that, due to an unusual positioning of Collembola, suggested that the hexapod body plan evolved at least twice. Here, we re-evaluate the position of Collembola using ribosomal protein gene sequences.