LIM-kinase 1 effects on memory abilities and male courtship song in Drosophila depend on the neuronal type.

The signal pathway of actin remodeling, including LIM-kinase 1 (LIMK1) and its substrate cofilin, regulates multiple processes in neurons of vertebrates and invertebrates. Drosophila melanogaster is widely used as a model object for studying mechanisms of memory formation, storage, retrieval and forgetting. Previously, active forgetting in Drosophila was investigated in the standard Pavlovian olfactory conditioning paradigm. The role of specific dopaminergic neurons (DAN) and components of the actin remodeling pathway in different forms of forgetting was shown. In our research, we investigated the role of LIMK1 in Drosophila memory and forgetting in the conditioned courtship suppression paradigm (CCSP). In the Drosophila brain, LIMK1 and p-cofilin levels appeared to be low in specific neuropil structures, including the mushroom body (MB) lobes and the central complex. At the same time, LIMK1 was observed in cell bodies, such as DAN clusters regulating memory formation in CCSP. We applied GAL4 × UAS binary system to induce limk1 RNA interference in different types of neurons. The hybrid strain with limk1 interference in MB lobes and glia showed an increase in 3-h short-term memory (STM), without significant effects on long-term memory. limk1 interference in cholinergic neurons (CHN) impaired STM, while its interference in DAN and serotoninergic neurons (SRN) also dramatically impaired the flies' learning ability. By contrast, limk1 interference in fruitless neurons (FRN) resulted in increased 15-60 min STM, indicating a possible LIMK1 role in active forgetting. Males with limk1 interference in CHN and FRN also showed the opposite trends of courtship song parameters changes. Thus, LIMK1 effects on the Drosophila male memory and courtship song appeared to depend on the neuronal type or brain structure.

Bioavailability and Safety of Dihydroquercetin (Review).

Dihydroquercetin (DHQ) is a bioflavonoid with high antioxidant, capillary-protective, and anti-inflammatory activity. DHQ has previously been used for treating Middle East respiratory syndrome coronavirus (MERS-CoV) infection and is currently considered a potential regulator of oxidative stress as part of COVID-19 multipurpose therapy. DHQ has a high safety profile but low bioavailability that limits its use. Innovative techniques (liposomization, crystal engineering, etc.) can be used to increase its bioavailability.

Parent-of-origin effects on nuclear chromatin organization and behavior in a Drosophila model for Williams-Beuren Syndrome.

Prognosis of neuropsychiatric disorders in progeny requires consideration of individual (1) parent-of-origin effects (POEs) relying on (2) the nerve cell nuclear 3D chromatin architecture and (3) impact of parent-specific miRNAs. Additionally, the shaping of cognitive phenotypes in parents depends on both learning acquisition and forgetting, or memory erasure. These processes are independent and controlled by different signal cascades: the first is cAMPdependent, the second relies on actin remodeling by small GTPase Rac1 - LIMK1 (LIM-kinase 1). Simple experimental model systems such as Drosophila help probe the causes and consequences leading to human neurocognitive pathologies. Recently, we have developed a Drosophila model for Williams-Beuren Syndrome (WBS): a mutant agnts3 of the agnostic locus (X:11AB) harboring the dlimk1 gene. The agnts3 mutation drastically increases the frequency of ectopic contacts (FEC) in specific regions of intercalary heterochromatin, suppresses learning/memory and affects locomotion. As is shown in this study, the polytene X chromosome bands in reciprocal hybrids between agnts3 and the wild type strain Berlin are heterogeneous in modes of FEC regulation depending either on maternal or paternal gene origin. Bioinformatic analysis reveals that FEC between X:11AB and the other X chromosome bands correlates with the occurrence of short (~30 bp) identical DNA fragments partly homologous to Drosophila 372-bp satellite DNA repeat. Although learning acquisition in a conditioned courtship suppression paradigm is similar in hybrids, the middle-term memory formation shows patroclinic inheritance. Seemingly, this depends on changes in miR-974 expression. Several parameters of locomotion demonstrate heterosis. Our data indicate that the agnts3 locus is capable of trans-regulating gene activity via POEs on the chromatin nuclear organization, thereby affecting behavior.

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. In the courtship suppression paradigm used in this study, Drosophila males that have been repeatedly rejected by mated females during courtship are less likely than naive males to court other females. Although numerous genes with known function were identified to play important roles in long-term memory, there is, to the best of our knowledge, no direct evidence implicating Hsp70 in this process. To elucidate a possible role of Hsp70 in memory formation, we used D. melanogaster strains containing different hsp70 copy numbers, including strains carrying a deletion of all six hsp70 genes. Our investigations exploring the memory of courtship rejection paradigm demonstrated that a low constitutive level of Hsp70 is apparently required for learning and the formation of short and long-term memories in males. The performed transcriptomic studies demonstrate that males with different hsp70 copy numbers differ significantly in the expression of a few definite groups of genes involved in mating, reproduction, and immunity in response to rejection. Specifically, our analysis reveals several major pathways that depend on the presence of hsp70 in the genome and participate in memory formation and consolidation, including the cAMP signaling cascade.

[To the study of the corpse tissues' impedance dynamics in the late postmortem period]. / K izucheniyu dinamiki impedansa tkanei trupa v pozdnem posmertnom periode.

The purpose of this work is to establish the dynamics of the electrical conductivity of various corpse tissues using impedance measurements to assess this method for diagnosing the time of death. It was studied the values of the tissue impedance from the corpses of 8 persons of both sexes and different ages (30-50 years) who died from various causes, with the known date of death. A Keysight U1731 parting was used with two probes, which are stainless steel needles with a diameter of 0.5 mm and a 5 mm immersion length. The analysis of special literature on using indicators of the electrical conductivity dynamics of the corpse tissues, determined by the method of impedance measurement, in the early and late postmortem periods to diagnose the time of death. Trial measurements of a methodological nature were carried out with diagnostic zones: skin, cartilage tissue and tendon. The impedance-metric approach is promising for the purposes of forensic medical diagnostics of the time of death; however, it requires more careful experimental work to establish the dynamics of changes in the total electrical resistance of various tissues of a whole corpse over a long period from the moment of death.

The Effects of Weak Static Magnetic Field on the Development of Organotypic Tissue Culture in Rats.

The effects of weak static magnetic field on the organotypic tissue culture of the rat cerebral cortex, liver, and spleen have been investigated. Exposure to a 200 µT static magnetic field induces tissue development, leading to the intensification of regeneration processes compared to the control explants.

[Effect of tryptophan and kynurenine on the cellular proliferation in the organotypic tissue culture of brain cortex in young and old rats.]

Metabolic disorders of L-kinurenin, which is an intermediate product of the breakdown of genetically encoded amino acid L-tryptophan, is one of the links in the development of a number of neuropathological processes. The influence of tryptophan and kynurenine on cell proliferation in organotypic tissue culture of the cerebral cortex in young and old rats was studied. Tryptophan in effective concentration (0,5 ng/ml) inhibited cellular proliferation of the cerebral cortex of young and old rats by 35 and 18%, respectively. However, under the action of kinurenin (1 ng/ml), stimulation of cell proliferation occurred, and more pronounced in the explants of the cerebral cortex of old rats-by 22% compared to the control. The data obtained about the ability of kynurenine to stimulate cellular proliferation in the cerebral cortex of old animals has the potential to create new drugs of nootropic drugs for diseases of the nervous system associated with age.

[Influence of limk1 Gene Polymorphism on Learning Acquisition and Memory Formation with pCREB Distribution and Aggregate Formation in Neuromuscular Junctions in Drosophila melanogaster].

We have shown previously that the polymorphic structure of the limk1 gene in drosophila leads to changes in LIMK1 content and to defects in courtship behavior, sound production, and learning/memory. The results of the present study of three wild-type strains and mutant agn(ts3) with altered limk1 structure demonstrate that long-term memory is normal in Canton-S and Oregon-R but is impaired in Berlin and drastically suppressed in agn(ts3). This temperature-sensitive mutant carries the S-element from the Tc1/mariner family insertion near the dlimk1 3'-UTR and, compared to Canton-S, has a reverse pCREB distribution in adult neuromuscular junctions (NMJ) of the second dorsal imago nerve before and after learning. Moreover, only agn(ts3) demonstrates amyloid-like aggregate formation in NMJ. This suggests that this impedes pCREb transport and thereby impairs the formation of short- and long-term memory.

[Neurogenetics and Neuroepigenetics].

"Genetics of behavior," or "Neurogenetics," is based on the evolutionary ideas of T. Dobzhansky on brain development and behavior. It continues with the "experimental genetics of higher nervous activity" of I. Pavlov and uses a comparative approach in the study of heredity and variation in behavioral manifestations, from Protozoa to humans. The study of the classical Pavlovian conditioned reflex in mutant Drosophila helped to identify the main types of memory and their evolutionary conservatism. Long-term memory defects are caused by mutations of the same genes as in mental, retardation in humans, when signaling cascades intersecting with the cAMP-dependent pathway are damaged. The cascade of actin remodeling is also among these. The key enzyme, LIM-kinase 1, controls cognitive manifestations of the "genomic disease" Williams deletion syndrome. Its study resulted in the recognition of neuroepigenetics as an interface between the genome and environmental influences. Epigenetic factors of "variability"--DNA methylation, histone acetylation, and microRNA regulation--do not change the structure of the gene but its manifestations. Certain miRNAs have already been considered to be both biomarkers for neurodegenerative diseases and factors of the intergenerational transmission of the behaviorial properties of ancestors who experienced stress from adverse environmental influences.

[Learning and memory in Drosophila: physiologic and genetic bases].

Elucidation of molecular mechanisms of cognitive functions is one of the major achievements in neurobiology. At most, this is due to the studies on the simple nervous systems, such as the CNS in Drosophila melanogaster. Many of its functional characteristics are pretty similar to higher vertebrates. Among these are: 1) evolutionary conservation of genes and molecular systems involved in the regulation of learning acquisition and memory formation; 2) presence of highly specialized and differentiated sensory, associative and motor centers; 3) utilization of similar modes of informational coding and analysis; 4) availability of major learning forms including non-associative, as well as associative learning; 5) diversity of different memories, including short-term- and protein synthesis- dependent long-term memory; 6) presence of aminergic reinforcement systems in the brain; 7) feed-back loops of circadian clocks, current organism experience and individual organism characters affecting cognitive process per se. In this review the main attention is paid to the two mostly studied Drosophila learning forms, namely to olfactory Iearning and courtship suppression conditioning (CCS). A separate consideration is given to the impacts of kynurenins and metabolite of actin remodeling signal cascade.

[Effect of heat shock on courtship behavior, sound production, and learning in comparison with the brain content of LIMK1 in Drosophila melanogaster males with altered structure of the LIMK1 gene].

In this paper we present results of a comprehensive analysis of the effect of heat shock at different stages of ontogenesis (adult stage, development of the mushroom bodies and the central complex) on courtship behavior (latency, duration and efficacy of courtship), sound production (pulse interval, dispersion of interpulse interval, the percentage of distorted pulses, the mean duration of the pulse parcels), learning and memory formation compared with the content of isoforms LIMK1 in Drosophila melanogaster male with altered structure of the limk1 gene. The heat shock is shown to affect the behavior parameters and LIMK1 content in analyzed strains of Drosophila. The most pronounced effect of the heat shock was observed at the stage of development of the central complex (CC). Heat shock at CC and adult restores the ability of learning and memory formation in the mutant strain agn(ts3), which normally is not able to learn and form memory. Correlations between changes of content of isoforms LIMK1 and behavioral parameters due to heat shock have not been established.

The Drosophila agnostic Locus: Involvement in the Formation of Cognitive Defects in Williams Syndrome.

The molecular basis of the pathological processes that lead to genome disorders is similar both in invertebrates and mammals. Since cognitive impairments in Williams syndrome are caused by LIMK1 hemizygosity, could the spontaneous and mutant variants of the Drosophila limk1 gene serve as a model for studying two diagnostic features from three distinct cognitive defects of the syndrome? These two symptoms are the disturbance of visuospatial orientation and an unusualy strong fixation on the faces of other people during pairwise interaction with a stranger. An experimental approach to the first cognitive manifestation might be an analysis of the locomotor behavior of Drosophila larvae involving visuospatial orientation during the exploration of the surrounding environment. An approach to tackle the second manifestation might be an analysis of the most natural ways of contact between a male and a female during courtship (the first stage of this ritual is the orientation of a male towards a female and following the female with constant fixation on the female's image). The present study of locomotor activity and cognitive repertoire in spontaneous and mutant variants of the Drosophila agnostic locus allows one to bridge alterations in the structure of the limk1 gene and behavior.

Williams syndrome as a model for elucidation of the pathway genes - the brain - cognitive functions: genetics and epigenetics.

Genomic diseases or syndromes with multiple manifestations arise spontaneously and unpredictably as a result of contiguous deletions and duplications generated by unequal recombination in chromosomal regions with a specific architecture. The Williams syndrome is believed to be one of the most attractive models for linking genes, the brain, behavior and cognitive functions. It is a neurogenetic disorder resulting from a 1.5 Mb deletion at 7q11.23 which covers more than 20 genes; the hemizigosity of these genes leads to multiple manifestations, with the behavioral ones comprising three distinct domains: 1) visuo-spatial orientation; 2) verbal and linguistic defect; and 3) hypersocialisation. The shortest observed deletion leads to hemizigosity in only two genes: eln and limk1. Therefore, the first gene is supposed to be responsible for cardiovascular pathology; and the second one, for cognitive pathology. Since cognitive pathology diminishes with a patient's age, the original idea of the crucial role of genes straightforwardly determining the brain's morphology and behavior was substituted by ideas of the brain's plasticity and the necessity of finding epigenetic factors that affect brain development and the functions manifested as behavioral changes. Recently, non-coding microRNAs (miRs) began to be considered as the main players in these epigenetic events. This review tackles the following problems: is it possible to develop relatively simple model systems to analyze the contribution of both a single gene and the consequences of its epigenetic regulation in the formation of the Williams syndrome's cognitive phenotype? Is it possible to use Drosophila as a simple model system?

[Complex approach to assessment of condition severity in patients with pyoinflammatory odontogenous diseases].

Dynamics of mean value indices and mean dispersion doesn't exclude the feedback (Mayanskiy D.N., 2008) in process of study the disease according to cooperative processes using system leukocyte-monocyte-lymphocyte (L+M+LM). The authors investigated a dynamic balance between these cell substratums and collagen formation. Acute inflammatory processes in tissues of maxillofacial area accompanied by leukemoid response of peripheral blood in the form of leukocytosis (10 x 10(9)-15 x 10(9)/l and more). The authors completely agree with the opinion of M.M. Solov'yov (2012) and N.K. Artyushenko (2008) that mechanism of this reaction is associated with both the leukocyte redistribution in the inflammation zone and with changes of hematopoietic rostock which aimed to balance the affected compensatory mechanisms of nonspecific resistance.

[Participation of GDNF, LIMK1 signal pathways and heat shock proteins in processes of Drosophila learning and memory formation].

Molecular mechanisms of the synapse and dendrite maintenance and their disturbance in psychiatric and neurodegenerative diseases (ND) are intensively studied in searching for target genes of therapeutic actions. It is suggested that glia, alongside with well-studied pre- and postsynaptic neurons, is the third, poorly studied partner in synaptic transmission (the tripartite synapse) that is involved in the positive feedback between the first two partners. This bidirectional coupling between presynaptic neurons and their postsynaptic targets involve neurotrophins (NTF), such as glial cell-derived neurotrophic factor (GDNF) that is produced LIM kinase 1 (LIMK1, the key enzyme of actin remodeling). The cytoplasmic domain of neuregulins interacts with LIMK1. Since neurons and axons that do not receive a sufficient NTF amount are at risk of degeneration and synapse elimination, GDNF seems to be the best studied factor of the ND therapy. The delivery of GDNF stem cells to the neurodegeneration locus is very efficient. There has been proposed a new approach based on use of Drosophila heat shock (hs) promoter. This promoter responds to the mammalian body temperature as to the shock factor resulting in the constant expression of the GDNF gene. The Drosophila models allow studying any given component of the bidirectional communication between pre- and postsynaptic neurons in development of the main diagnostic ND symptom, such as defective memory resulted from synaptic atrophy. In the present study we used the Drosophila stocks imitating different disturbances of the nervous system: Canton-S (wild type), GDNF (transgenic flies that carry human glial-cell-line derived nerve factor (GDNF) gene under hs promoter), l(1)ts403 with dusturbance of HSPs mRNA extranuclear transport, a defect of intracellular stress report, and agn(ts3) mutation in LIMK1 gene. We have revealed functional connections at the behavioral level (learning/memory) depending on the GDNF and LIMK1 brain expression and HSPs transduction that might provide targets for complex approaches for the ND treatment.

Association constants and distribution functions for ion pairs in binary solvent mixtures: application to a cyanine dye system.

The computations of the association constants K(ass) were performed at the microscopic level for the ion pair Cy(+)I(-) composed of the complex cyanine dye cation Cy(+) coupled to the negative iodine counterion. The wide array of K(ass) values is arranged by a variation of the composition of the binary solvent mixtures toluene/dimethylsulfoxide with the accompanying change of the solvent polarity. The potentials of mean force (PMFs) are calculated for a set of interionic separations R in the Cy(+)I(-) by a methodology which combines the quantum-chemical techniques for the treatment of the electronic structure of the Cy(+)I(-) system with the recent dielectric continuum approach which accounts for the solvation effects. For a given solute/solvent system the probability function P(R), which describes the distribution of interionic separations, is constructed in terms of the PMFs and implemented for the evaluation of the K(ass).

[Systemic regulation of genetic and cytogenetic processes by a signal cascade of actin remodeling: locus agnostic in Drosophila].

The concept on systemic regulation of genetic and cytogenetic processes has acquired a new perspective after the completion of the Human Genome project, when the view on systemic realization of genetic activity in the dynamic spatial organization of the genome is the nucleus was generally accepted. This organization underlies plasticity of complex biological systems. Chromosome position within the nucleus determined both processes of normal development and the development of genomic diseases, i.e., changes according to the environmental requirements, current needs of the organism, and its individual experience. Nuclear actin has been envisioned as a main factor bridging three levels of the genome organization (nucleotide, structural, and spatial), due to its capability of (1) regulating transcription by activating all three classes of RNA polymerase; (2) participating in chromatin remodeling by interacting with numerous proteins; and (3) lining the nuclear membrane, determining the chromosome attachment points and regulating export from the nucleus. In view of this, the role of actin remodeling factors (LIMK1, cofilin, actin) in the development of neurodegenerative diseases, including prionic ones, and in the mechanisms of generation of genomic diseases, syndromes resulting from unequal recombination, has been intensely studied. Drosophila is a helpful model organism to determine the sequence of events in this system of hierarchical relationships. Using spontaneous and mutant variants of the agnostic locus, we have designed a model of the Williams syndrome, which also reproduces main diagnostic traits of neurodegenerative diseases.

Computation of entropy contribution to protein-ligand binding free energy.

The entropy contribution DeltaS to protein-ligand binding free energy is studied for nine protein-lipid complexes. The entropy effect from the loss of the translational/rotational degrees of freedom (DeltaStr) is calculated using the ideal gas approach. The change in the vibrational entropy (DeltaSvib) is calculated using the effective quantum oscillator approach with frequencies derived from the coordinate covariance matrix, so the inharmonic effects are taken into account. The change in the entropy of solvation (DeltaSsolv) is considered using the binomial cell model (developed by the authors) for the hydrophobic effect. The entropy contribution from loss of conformations that are available for the free ligand (DeltaSconf) is also estimated. It is revealed that the negative in view of binding term DeltaStr is only partly compensated by increasing of DeltaSvib, so T(DeltaStr+DeltaSvib+DeltaSconf)<0 for all complexes under investigation, but taking into account DeltaSsolv leads to significantly increased DeltaS. For all complexes except biotin-streptavidin, the results are found to be in reasonable agreement with experimental data.

[Semidominant effect of the l(1)ts403 (sbr10) mutation on nondisjunction of sex chromosomes in meiosis in Drosophila melanogaster females exposed to heat]. / Poludominantnoe vliianie mutatsii l(1)ts403 (sbr10) na neraskhozhdenie polovykh khromosom v meioze u samok Drosophila melanogaster pri teplovom vozdeistvii.

The sbr gene of Drosophila melanogaster belongs to the NXF (nuclear export factor) family responsible for the mRNA transport from nucleus to cytoplasm. We have shown that in the heat-exposed (37 degrees C, 1 h) females, the l(1)ts403 (sbr10) mutation leads, in particular, to the high-frequency nondisjunction and loss of sex chromosomes in meiosis. For this trait, the incomplete dominance of the sbr10 mutation is observed. At the same time, the sbr10 mutation is recessive for many other traits of the heat-exposed flies: reduced viability, low fertility, impaired synthesis of the heat shock proteins, etc. The females heterozygous for the null allele (Df(1)vL4, a deletion eliminating gene srb) do not differ from females homozygous for the wild-type allele in frequency of the heat shock-induced nondisjunction and loss of sex chromosomes in meiosis. Because of this, the sbr10 mutation can be assigned to the gain-of-function alleles (those gaining the dominance function). Expression of the mutant sbr10 allele against the background of the wild-type allele suggests that in the heat shock-exposed females, the heat-modified product of this ts allele has a strong effect on sex chromosome disjunction in meiosis.

[Heat shock during the development of brain structures of Drosophila: the memory development in the l(1)ts403 mutant of Drosophila melanogaster]. / Teplovoi shok v period razvitiia tsentral'nykh struktur mozga drozofily: formirovanie pamiati u mutanta l(1)ts403 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. In view of this, we used Drosophila mutant l(1)ts403 with defective synthesis of heat shock proteins for studying learning and memory in a test of conditioned courtship suppression following a heat shock given at different developmental stages. High learning indices were registered immediately and 30 min after training both in the intact controls and in flies subjected to different developmental heat shocks. This indicated normal learning and memory acquisition in the mutant. At the same time, memory retention (3 h after training) suffered to different extent depending on the developmental stage. The remote effects of heat shock given during the formation of the mushroom bodies indicated the important role of this brain structure in the memory formation. The observed memory defects may result from alterations both in mRNA transport and in the functions of molecular chaperones in the l(1)ts403 mutant.