Disturbances of basic self and prodromal symptoms among non-psychotic help-seeking adolescents.

BACKGROUND: The goal of this study was to explore the notion that anomalies of self-experience (ASE) are a core, 'not-yet-psychotic' clinical phenotype of emerging schizophrenia and its spectrum. Method To accomplish this goal, we examined the relationship between ASE and commonly accepted risk markers in a sample of 87 help-seeking, non-psychotic adolescents (aged 14-18 years). ASE were assessed with the Examination of Anomalous Self-Experience (EASE), subclinical psychotic symptoms were assessed with the Prodromal Questionnaire and the Structured Interview for Prodromal Syndromes, deterioration in psychosocial functioning was assessed with the Social and Role Functioning Scales, and level of distress with the Mood and Anxiety Symptoms Questionnaire. RESULTS: About 82 participants completed the entire EASE interview. The number of participants who reported ASE at a clinically meaningful level (n = 18, 22%) was smaller than that who met diagnostic criteria for a prodromal syndrome (n = 28, 34%). The degree of overlap between the two conditions was moderate but statistically significant (χ2 (1) = 7.01, p = 0.008). An exploratory factor analysis revealed that ASE load on a different factor than prodromal symptoms and deterioration in functioning, but that there is a moderate correlation between the three factors. CONCLUSIONS: These results suggest that ASE are prevalent among non-psychotic help-seeking adolescents, yet at a considerably lower rate than prodromal symptoms. In addition, they suggest that ASE and prodromal symptoms constitute distinct but moderately related dimensions of potential risk. Taken together, they provide preliminary support for the clinical usefulness of supplementing and refining the methods of early detection of risk with assessment of ASE.

[Dynamics of mitochondrial polymorphism in a natural population of Drosophila littoralis].

During seven years, we observed stable mtDNA polymorphism in a local population of Drosophila littoralis. Using RFLP, a number of mitochondrial haplotypes were revealed, two of which were the core and in condition of stable equilibrium. To explain the absence of fixation of one haplotype, we checked a hypothesis that the D. littoralis population had a complex structure, being subdivided into several partially isolated races existing on the same territory. Analysis of highly hypervariable nuclear sequence of retrotransposons Tv1 showed positive correlation of the mitochondrial haplotype with a particular allelic form of Tv1. This supports the proposal that the D. littoralis natural population forms the population system consisting of genetically differentiated races.

[The endosymbiotic bacterium Wolbachia enhances the nonspecific resistance to insect pathogens and alters behavior of Drosophila melanogaster].

To determine biologically important effects of the cytoplasmic endosymbiont Wolbachia, two substrains of the same Drosophila melanogaster strain have been studied, one of them infected with Wolbachia and the other treated with tetracycline to eliminate the bacterium. Female D. melanogaster infected with Wolbachia are more resistant to the fungus Bauveria bassiana (an insect pathogen) than uninfected females; infected females also exhibited changes in oviposition substrate preference. Males infected with the bacterium are more competitive than uninfected males. The possible role of Wolbachia in the formation of alternative ecological strategies of D. melanogaster is discussed.

[The prospects for studying the induced genetic instability unber the spaceflight conditions].

Consideration is given to the facts of mutagenesis during orbital space flight and tangibility of development for and application of genetic tests to space crewmembers based on the present-day concepts about the cellular mechanisms of genome maintenance and destabilization.

Gypsy group retrotransposon Tv1 from Drosophila virilis.

We have determined the nucleotide sequence of the 6868 bp full-size retrotransposon termed 'Tv1'. Tv1 was isolated from the DNA fraction of extracellular virus-like particles of Drosophila virilis culture cells. Tv1 has the typical structure for a gypsy-group retrotransposon. The Tv1 element was found to be flanked by 453 bp long terminal direct repeats identical to each other. The central part of the element contains three long open reading frames which resemble the gag, pol and env genes of retroviruses. ORF2 includes conservative motifs of protease, reverse transcriptase, RNase H and integrase in the order characteristic for the gypsy-group retrotransposons. Although most copies of Tv1 are located in pericentromeric heterochromatin, the amplification of this family demonstrated in the cell culture and site polymorphism observed in different Drosophila strains suggest functional activity of the Tv1 element.

[Expression of homologous and heterologous retrotransposons in a model system of yeast cells]. / Ekspressiia gomologichnykh i geterologichnykh retrotranspozonov v model'noi sisteme drozhzhevykh kletok.

Yeast cells Saccharomyces cerevisiae were transformed by the recombinant plasmids containing the Yeast retrotransposon Ty and the Drosophila mobile element gypsy under the control of a strong Yeast promoter. The exogenous Ty-element induces the complete cycle of Ty-retrotransposition including the TyRNA synthesis, formation of virus-like particles, synthesis of all reverse transcriptase intermediates in the virus-like particles with the subsequent circles formation and transposition. The Drosophila mobile element gypsy is capable of inducing the formation of the virus-like particles containing RNA, DNA and proteins of the Ty-retrotransposon only. The Ty-circles and induction of transposition were not observed. The obtained data demonstrates the existence of the multistep repression system for Ty-transposition cycle. The possibility and efficiency of using the model to study the mechanism for retrotransposon transposition is discussed.

[Expression of Drosophila retrotransposon in yeast]. / Ekspressiia retrotranspozona drozofily v drozhzhakh.

The recombinant plasmids pPTX and pPGX were constructed, containing the sequences of yeast Ty retrotransposon and Drosophila element mdg4, correspondingly. Transformation of yeast by these plasmids lead to induction of reverse transcriptase activity associated with virus-like particles, containing only the sequences of Ty. The data obtained show that mdg4 is capable of expression in yeast and the products of its expression are used to form the yeast virus-like particles. The system described may be used to study the expression of different retrotransposons from various cells in yeast.

[Phenotypic manifestations of reverse transcriptase activity in yeast cells]. / Fenotipicheskoe proiavlenie aktivnosti obratnoi transkriptazy v drozhzhevykh kletkakh.

The yeast Saccharomyces cerevisiae and Schizosaccharomyces pombe transformed by plasmids containing retrotransposon from yeast or Drosophila under the control of a strong promoter show the remarkable reverse transcriptase activity. The activity results in the impaired yeast growth and decreased mitotic stability of the plasmids. The phenotypic expression of the reverse transcriptase activity is observed within 30 days.

[Evidence of single-strandedness in eukaryotic chromosomes]. / Dokazatel'stvo odnonitchatosti khromosom éukariot.

Polytene salivary gland chromosomes of Chironomus thummi were stretched in pronase solution by 176 +/- 26 times up to their break (fig. 1). The DNA packed arrangement coefficient, determined as a ratio of DNA length, equal to 85 +/- 5 mm in a haploid set, to the length of 520 +/- 40 microns of a set of polytene chromosomes was found to be 164 +/- 22. The coincidence of these two values is a very strong evidence in favour of the uninemity of chromatids of the Chironomus chromosomes. The effect of ethidium bromide on elastic properties of chromosomes, preliminary stretched in pronase (fig. 2), and the lengthening of these chromosomes after ethidium staining prove that DNA molecules are double-stranded and supercoiled until chromosomes are broken. This enables us to conclude that each chromatid of Chironomus consists of a single DNA molecule or, more probably, of a single chain of linked DNA molecules whose both ends are located in telomeres of chromosomes.

[Changes in the cellular structure of the salivary glands in Chironomus larvae resulting from mechanical cell damage]. / Izmenenie struktury kletok sliunnykh zhelez lichinok khironomusa v rezul'tate mekhanicheskogo povrezhdeniia kletok.

Rapid morphological changes were observed in some cells of hand-isolated salivary glands of Ch. thummi larvae. The nuclear envelope, routinely closely fitting the tightly packaged polytene chromosomes, was seen to lose its contact with the chromosomes and to attain a smooth round shape. Then unfolding of the chromosomes occurred, their banding patterns becoming clearly evident, probably through widening the interband regions; the chromosome length increased by about 20%. We argue that the changes observed were induced during gland isolation by lesions of the cell basal envelope in the sites of the fat body connections to the salivary gland.

[Preparation and properties of elongated polytene chromosomes. I. The method]. / Poluchenie i svoistva rastianutykh politennykh khromosom. I. Metod.

Compactness of eukaryotic, particularly polytene chromosomes pose difficulties for investigation of their functional organization. For example, 0.1 --1.0 micrometer thick bands of polytene chromosomes contain some dozens microns pieces of DNA molecules. Therefore the useful resolving power of autoradigraphical methods is reduced by 10--100 times of its upper limit. To overcome the mentioned difficulty, a new method has been developed which permits to attain the upper limit of resolution. An isolated polytene chromosome from salivary gland nucleus of Chironomus thummi larva is stretched by microneedles to obtain a bundle of oriented DNP-fibers. A previously chosen small region of the chromosome (band or puff) is stretched simultaneously in a transverse direction by a stick frame made of another chromosome. Electron microscopy of the preparation reveals a meshwork of DNP fibers as presented on fig. 6.

[Stretched polytene chromosomes--model for studying the functional organization of eukaryotic chromosomes]. / Rastianutye politennye khromosomy--model' dlia izucheniia funktsional'noi organizatsii khromosom éukariot

To localize functional loci on cytological maps of polytene chromosomes we propose to use 10-100 times stretched chromosomes. Three different ways of stretchening are briefly considered: the squash tissue preparation, when chromosomes are stretched by hydrodynamical forces; the treatment of isolated polytene chromosomes in 10-minus 4M EDTA OR 0.8M NaCL with subsequent change of these solution for saline when abrupt structural changes occur in chromosomes and they become morphologically homogeneous threads (Gruzdev and Belaya, 1973); and, finally, the use of microneedles of the micromanipulator. After an intense (ca. 100 times) stretchening, the autoradiography is sufficient to localize the loci within one micron length of double helical DNA molecule.

[Heterologous induction of the retrotransposon Ty1: reverse transcriptase plays a key role in initiating the retrotransposition cycle]. / Geterologichnaia induktsiia retrotranspozitsii Ty1: obratnaia transkriptaza igraet kliuchevuiu rol' v zapuske tsikla retrotranspozisii.

A new method was developed to study the mechanism of initiation of the retrotransposition cycle: retrotransposons of Drosophila melanogaster, gypsy, copia, and 17.6 were expressed in yeast under the control of potent yeast promoters. Expression of retrotransposons induced formation of viruslike particles (VLPs) associated with full-length Ty1 RNA and DNA sequences. This phenomenon was termed heterologous induction. When the gene for reverse transcriptase of human immunodeficiency virus (HIV) was expressed in yeast, the same results were obtained. These data allowed us to assume the excess of active reverse transcriptase to play the central role in induction of transposition. Possible mechanisms of induction of Ty1 transposition by homologous and heterologous elements are discussed.

[Polymorphism of virus-like particles of retrotransposons in Drosophila and yeast cells]. / Polimorfizm virusopodobnykh chastits retrotranspozonov v kletkakh drozofily i drozhzhei.

Data on the molecular arrangement of viruslike particles (VLPs) of yeast and Drosophila retrotransposons are presented. Two methods for identifying VLPs from specific retrotransposon families have been offered. The first method is based on VLPs fractionation by electrophoresis in agarose gel under strictly controlled conditions. VLPs of the Drosophila melanogaster retrotransposon families copia and gypsy and D. virilis retrotransposon Tv1 were identified by this method. The method based on heterologous induction of retrotransposons in cells of the mutant spt3 strain of Saccharomyces cerevisiae was used to identify VLPs of yeast retrotransposon Tyl and D. melanogaster gypsy retrotransposon.