Hsp70 affects memory formation and behaviorally relevant gene expression in Drosophila melanogaster.

Heat shock proteins, in particular Hsp70, play a central role in proteostasis in eukaryotic cells. Due to its chaperone properties, Hsp70 is involved in various processes after stress and under normal physiological conditions. In contrast to mammals and many Diptera species, inducible members of the Hsp70 family in Drosophila are constitutively synthesized at a low level and undergo dramatic induction after temperature elevation or other forms of stress.

[Heat shock during the development of brain structures of Drosophila: the memory development in the l(1)ts403 mutant of Drosophila melanogaster].

The structures and functions of many genes are homologous in Drosophila and humans. Therefore, studying pathological processes in Drosophila, in particular neurogenerative processes accompanied by progressive memory loss, helps to understand the ethiology of corresponding human disorders and to develop therapeutic strategies. It is believed that the development of neurogenerative diseases might result from alterations in the functioning of the heat shock/chaperone machinery.

The ability of Drosophila mutants with defects in the central complex and mushroom bodies to learn and form memories.

One of the most important questions in the genetics of behavior is that of studies of the mechanisms of learning and memory. A convenient system for this is provided by Drosophila melanogaster, in which a whole series of mutations affecting the formation of different types of memory and learning have been obtained. The brain formations involved in these processes have been studied in parallel.

[Learning ability and memory formation in the Drosophila mutants with defective central complex and mushroom bodies].

Drosophila proved to be a very convenient model for genetic dissection of learning and memory in a number of experimental paradigms. A battery of mutations affecting either different subdomains of the central complex (CC) or of the mushroom bodies (MBs) enable the elucidation of the role of these central brain structures in different forms of learning and memory formation. We tested the CC mutants cexKS181 and ccbKS127 and MBs mutants mud1, mbm1 and cxbN71 for their ability for learning and memory formation in the conditioned courtship suppression paradigm.

Identification of Drosophila mutant with memory defects after acquisition of conditioned reflex suppression of courtship.

Four lines were selected from a collection of 33 lines prepared by P insertion mutagenesis using a single-copy P-element system; the males of these four lines showed memory defects after acquisition of conditioned reflex suppression of courting. In two lines (P171 and P95), the dynamics of retention of the conditioned reflex in the repeated impregnated-female courting test were similar to those of known short-term memory mutants dnc and rut. In line P153, the dynamics were more reminiscent of the memory dynamics in a known medium-term memory mutant, amn.

[Isolation of memory-deficient Drosophila mutants in conditioned courtship suppression paradigm].

Among 33 mutant stocks of Drosophila melanogaster generated by means of P-insertional mutagenesis in the system with single P element, 4 stocks have been isolated as demonstrating deficient memory in the conditioned courtship suppression paradigm. Localization of the P insertions never coincided with that of previously known mutations affecting memory.

[Structural-functional chromosome organization in response to stress].

Published data and the results of experiments conducted at the Laboratory of Genetics of Higher Nervous Activity, Pavlov Institute of Physiology, on the effect of stress on chromosome structure and function are reviewed briefly. Experiments were performed on inbred rats selected for excitation threshold and mutant Drosophila with altered metabolism of secondary mediators.

Organization of the Drosophila genome in mutants with changes in second messenger metabolism and learning ability.

Mechanisms modifying the structural-functional organization of polytene chromosomes were studied in a Drosophila line in which the activating properties of calmodulin were altered and learning ability was increased, by treating mutants with homeopathic preparations which affect Ca2+ and F- ion metabolism. The results indicated a dominant role for Ca2+ ions and calmodulin in determining the chromocentric organization of the nucleus. F- ions, which stimulate the adenylate cyclase complex, were found not to have a role.

Study of the activity of head ganglion cells of larvae of the Drosophila ts-mutant with altered capacity for learning and increased activational properties of calmodulin.

The mitotic activity of cells of the head neural ganglion of Drosophila larvae of two genetic lines, the agts 3-mutant line, which possesses increased calmodulin activational properties and altered capacity for learning, and the wild type CS line, serving as a control, was studied. The value of the mitotic index, as a ratio of the number of dividing cells to their total number, was assessed. The mitotic index was calculated following the exposure of the larvae to a temperature of 37 degrees C for 30 min, and without exposure, at a temperature which was standard for the maintenance of Drosophila ts-mutants, 22 degrees C.

[The organizational characteristics of the Drosophila genome in mutants with altered second-messenger metabolism and with learning ability].

The data obtained on homeopathic correction of the Drosophila mutant strains with altered activation properties of calmodulin and increased ability for learning, suggest an important role of Ca ions calmodulin in formation of chromocentral organisation of the nucleus. No significant role of the F ions was revealed.

[The mitotic activity of the cells in the head neural ganglion in larvae of the Drosophila ts mutant with an altered capacity for learning and augmented calmodulin activation properties].

Mitotic activity of head neural ganglion cells of Drosophila melanogaster larvae from two genetic stocks was studied. The mutant stock agts3 with augmented activatory potentialities of calmodulin and modified capacity for learning was compared with the control wild type Canton-S stock. The mitotic index was defined as the ratio of the number of cells in the state of division to the total cell number.