[Species-specific localization of DNA from pericentromeric heterochromatin on polytene chromosomes in the salivary gland cells and 3D-nuclear organization nurse cells in Drosophila virilis, and Drosophila kanekoi (Diptera: Drosophilidae)].

Microdissection of the chromocenter of D. virilis salivary gland polytene chromosomes has been carried out and the region-specific. DNA library (DvirIII) has been obtained. FISH was used for DvirIII hybridization with salivary gland polytene chromosomes and ovarian nurse cells of D. virilis and D. kanekoi. Localization of DvirIII in the pericentromeric regions of chromosomes and in the telomeric region of chromosome 5 was observed in both species. Moreover, species specificity in the localization of DNA sequences of DvirIII in some chromosomal regions was detected. In order to study the three-dimensional organization of pericentromeric heterochromatin region of polytene chromosomes of ovarian nurse cells of D. virilis and D. kanekoi, 3D FISH DvirIII was performed with nurse cells of these species. As a result, species specificity in the distribution of DvirIII signals in the nuclear space was revealed. Namely, the signal was detected in the local chromocenter at one pole of the nucleus in D. virilis, while the signal from the telomeric region of chromosome 5 was detected on another pole. At the same time, DvirIII signals in D. kanekoi are localized in two separate areas in the nucleus: the first belongs to the pericentromeric region of chromosome 2 and another to pericentromeric regions of the remaining chromosomes.

[Comparison of nucleotide sequences of ribosomal DNA of the mosquito genera Aedes and Ochlerotatus (Diptera: Culicidae: Aedini)].

Morphological study allowed identifying 9 species of mosquitoes of the genus Ochlerotatus and 2 species of the genus Aedes. Sequencing of the rDNA region was performed for all these speciemens. The sequences of rDNA were the following: A. cinereus -868 bp, A. vexans--889 bp, Och. cantans--803 bp, O. excrucians--801 bp, O. euedes--794 bp, Och. cyprius--777 bp, O. diantaeus--758 bp, O. intrudens--817 bp, Och. punctor--783 bp, O. dorsalis--748 bp, O. species--767 bp. On average, the size of Aedes rDNA fragments exceeds rDNA of Ochlerotatus by 90-100 bp. The sequences are characterized by a high number of insertions and deletions, and also by point substitutions of nucleotides. It is important to notice that interspecific differences include not only different regions of the internal transcribed spacers, but also the conservative site which is represented by the 5.8S gene. Among four substitutions in this gene, one (C/A) represents the difference between Aedes and Ochlerotatus, the next (T/A) distinguishes A. cinereus from Ochlerotatus speciment and A. vexans, and two substitutions (A/C, T/G) testify the similarity between O. dorsalis and O. species and specimens of Aedes. Besides, two more deletions are typical for O. dorsalis and O. species. One deletion is com- mon, it distinguishes them from the other examined species, and another one is typical only for O. dorsalis. When analyzing morphological characteristics and comparing nucleotide rDNA sequences of O. species with the database, the similarity to O. caspius has been revealed. On the whole, phylogenetic relationships among Ochlerotatus species correspond to subdivision into groups based on morphological characters. Probably, examination of the larger number of specimens will change the morphological division into groups.

[Study of the organization of polytene chromosomes in the nuclei of Drosophila melanogaster pseudonurse cells with the use of the DNA library of the Drosophila orena chromocenter].

The location of the Drosophila orena chromocenter in polytene chromosomes of pseudonurse cells of the D. melanogaster ovaries (the otu11 mutation) and salivary glands has been studied. Numerous sites of location of the D. orena chromocenter DNA have been found throughout the length of D. melanogaster chromosomes. The specific distribution of the binding sites for the DNA probe has made it possible to identify chromosomes and analyze their mutual positions in the three-dimensional space of the nuclei of pseudonurse cells. The mutual positions of chromosomes have been found to vary, the pericentromeric regions of different chromosomes differing from one another in associative ratios.

[Analysis of the chromocenter DNA composition in polytene chromosomes of Drosophila orena ovarian nurse cells].

Chromocenter DNA fragments of polytene chromosomes of Drosophila orena ovarian nurse cells were cloned from a region-specific library (Dore 1) in a plasmid vector to yield 133 clones. A total of 76 clones were selected and sequenced. The total length of the sequenced fragments was 23940 bp. Analysis with several software packages revealed various repetitive sequences among the fragments of the Dore 1 library, including mobile genetic elements (25 fragments homologous to various LTR retrotransposons, five fragments homologous to LINEs, three fragments homologous to Helitrons, one fragment homologous to Polinton, and one fragment homologous to the mini-me non-LTR retrotransposon), four minisatellites, a satellite (SAR_DM), the (TATATG)n simple sequence repeat, and a low-complexity T-rich repeat. Sequences homologous to protein-coding genes were also found in the Dore 1 library. Various repetitive DNA sequences and gene homologs were identified as conserved sequences of pericentric heterochromatin of polytene chromosomes of ovarian nurse cells in nine species of the melanogaster species subgroup.

[Molecular genetic analysis of the X-chromosomal nuclear envelope attachment region in nurse cells of the malaria mosquitoes Anopheles messeae Fall].

DNA of the X-chromosomal nuclear envelope attachment region was isolated from malaria mosquito Anopheles messeae Fall. nurse cells by chromosome microdissection. A DNA library of the region was constructed using a plasmid vector. DNA sequencing revealed gene fragments, tandem repeats, and a great variety of transposable elements (TEs). The X-chromosomal nuclear envelope attachment region was concluded to correspond in molecular organization and cytogenetics to diffuse intercalary heterochromatin.

[Intranuclear dynamics of chromosome 6 in nurse cells of Calliphora erythrocephala Mg. (Diptera: Calliphoridae)].

Intranuclear dynamics of chromosome 6 in nurse cell nuclei of Calliphora erythrocephala Mg. (Diptera: Calliphoridae) was studied. The 3D FISH method was used for the first time to study chromosome territories in highly polyploid nuclei whose chromosomes undergo morphological changes. A considerable change in the intranuclear location of chromosome 6 and a morphological alteration of the chromosome territory in the course of chromatin polytenization were revealed.

[Analysis of the spatial organization of the XL chromosome attachment site in nurse cell nuclei of the malaria mosquito Anopheles atroparvus].

The spatial position of the site of XL chromosome attachment to the nuclear envelope of ovarian nurse cells relative to the oocyte has been analyzed in the malaria mosquito Anopheles atroparvus. The XL chromosome attachment sites in the oocyte-nurse cell system of this species have been demonstrated to be orderly arranged, with the attachment sites in two out of three nurse cells in the same layer identically oriented relative to the oocyte.

[Development of ovarioles and nurse cells cytoskeleton in Calliphora erythrocephala Mg. (Diptera; Calliphoridae)].

We have carried out the analysis of ovariole development and morphology in Calliphora erythrocephala Mg. (Diptera: Calliphoridae). It has been shown that several regions can be distinguished in C. erythrocephala germarium. In these regions cyst morphogenesis goes on stage by stage right up to the separation of formed egg chamber. There are fusomes of different degree of branching in germarium. Two egg chambers develop in C. erythrocephala vitellarium. We have researched distribution of actin filaments and ring canals formation in the nurse cells of C. erythrocephala. Diameter of ring canals increases from 1.5 microm in germarium zone to 14.7 microm at 3 and 4 stadies oogenesis. We suggest the scheme that illustrates irregular stretching of actin rollers which are formed during middle and late oogenesis around the ring canals joining proximal, sharply increased in size nurse cells with neighboring nurse cells.

[Analysis of sex chromosome homologies in representatives of the family Calliphoridae].

The distribution of sequences homologous to the Calliphora erythrocephala Mg. sex chromosome was studied in Protophormia terranovae R-D and Lucilia sp. The chromatin structure was found to be similar in regions containing homologous DNA sequences.

[Molecular composition of the chromosome 2 pericentric heterochromatin in malarial mosquitoes (Diptera, Culicidae)].

Rich in repeated DNA sequences and poor in genes, the heterochromatin is an important functional part of the eukaryotic genome. Heterochromatin exhibits high evolutionary variability, which was revealed on the cytological and molecular levels in malarial mosquito species from the Anopheles maculipennis complex. In this connection, investigation of the heterochromatin molecular composition in species of this complex is of interest.

[Inversion polymorphism in malarial mosquito Anopheles messeae natural populations from the north-eastern region of the range].

A cytogenetic study of eight natural populations of Anopheles messeae from the north-eastern part of the species areal was conducted. Complete predominance of homozygotes XL11 and 3R11 in the northern populations was observed. Change in the chromosome 2 inversion frequencies from south northwards was shown. The 2R11 variant, which was not observed in the southern region, was found in the northern populations. These results indicate the maintenance of chromosome frequency of the distribution of inversions XL1 and 3R (in longitude) and 2R1 (in latitude). The inversion frequency distribution in the examined part of the areal have been preserved for a long time.

[Molecular cytogenetic analysis of DNA from pericentric heterochromatin of chromosome 2L of malaria mosquito Anopheles beklemishevi (Culicidae, Diptera)].

Using the method of microdissection of polytene chromosomes, followed by in situ hybridization, chromosomal localization of region-specific DNA probe from pericentic heterochromatin of chromosome 2L of Anopheles beklemishevi Stegnii et Kabanova was examined on polytene chromosomes of Anopheles atroparvus van Thiel, An. messeae Fall, and An. beklemishevi. DNA sequences homologous to the probe used were found in all species examined on chromosomes 2 and 3 in pericentric regions and in attachment regions. The exclusion were the attachment regions of chromosome XL in An. beklemishevi and An. messeae, and pericentric region of arm 2R in An. messeae. Pericentric a-heterochromatin of arm 2L in An. messeae and arm 3R in An. atroparvus also contained no sequences homologous to the DNA probe. The data obtained were compared with the earlier obtained data on localization of species-specific probe from the segment of chromosome 2R of An. atroparvus on chromosomes of An. artoparvus, An. messeae, and An. beklemishevi. The differences between the species in the sites of probes localization and fluorescence intensity revealed pointed to the existence of individual sequence associations in the regions of chromosomes attachment.

[The effects of inbreeding and low temperature on the pattern of chromosome synapsis in the ovarian nurse nuclei of Drosophila melanogaster strains].

The effects of inbreeding and low temperature on the pattern of homologous chromosome synapsis in ovarian nurse cell nuclei of Drosophila melanogaster strains were studied. Exposure to decreased temperature (16 degrees C) caused a noticeable increase in the rate of asynapses of homologous chromosomes, whereas this effect was insignificant for F30 inbreeding generation. Long-term inbreeding has a substantial effect on the relative positions of chromosomes in the nurse cell nuclei. This is visually evident only in the interstrain hybrids between highly inbred strains LA (F923) and HA (F923) or between either strain and laboratory strain Canton S or the flies from the natural population, where abnormalities in homologous chromosome synapsis are observed in virtually all nuclei.

[Molecular-cytogenetic analysis of pericentromeric heterochromatin in ovarian nurse cells of Drosophila melanogaster subgroup species].

Evolutionary rearrangements of pericentromeric heterochromatin among Drosophila melanogaster subgroup species have been investigated. Region-specific DNA library from Drosophila orena ovarian nurse cell chromocenter has been obtained by microdissection of polytene chromosomes. The probe was localized on ovarian nurse cells chromosomes of D. melanogaster subgroup species using fluorescent in situ hybridization. Sequences homologous to the sequences of the DNA-probe were found in chromocenter and pericentromeric regions of D. orena polytene chromosomes; and in all pericentromeric regions of other species with several exceptions. So, there was no labeling on one of the arms of D. simulans chromosome 2 but such sequences were present on telomere of D. erecta chromosome 3 and in regions adjacent to the brightly DAPI-stained heterochromatic blocks of D. yakuba, D. santomea and D. teissieri chromosomes 2 and 3. At S6 stage (secondary reticulate nucleus), the labeled chromatin in D. orena could be found mostly within a restricted area and no such chromatin could be detected throughout the rest of the nucleus. On the contrary, the labeled DNA was spread diffusely in the nuclei of other species at this stage.

[Morpho-cytogenetic characteristic of the mosquito Anopheles artemievi (Diptera: Culicidae), a malaria vector from the complex maculipennis].

Detailed morphological analysis of all stages of the mosquito Anopheles artemievi Gordeev et al., 2005 is carried out. Characteristic traits that allow discriminating of An. artemievi and An. messeae Falleroni, 1926 in the area of joint occurrence of these two species are provided. Cytogenetic description of the polytene chromosomes from the nurse cells of ovaries is given. Differences of An. artemievi from previously studied species of the complex maculipennis by the structre of the polytene chromosomes from the nurse cells of ovaries are shown.

[Morphological and genetic characteristics of the malarial mosquito Anopheles beklemishevi (Diptera, Culicidae)].

The paper presents morphological and genetic data on the malarial mosquito Anopheles beklemishevi Stegnii et Kabanova, 1976. It also provides morphological accounts of eggs, age stage IV larvae, and, firstly, pupae and imagoes. The paper considers it possible to use cytogenetic and molecular markers to identify An. beklemishevi.

[Evolutionary significance of chromosome architecture for epigenetic control of eukaryote development and phylogeny].

The significance of the spatial organization of chromosomes in germline tissue as a positional system controlling segregation in oogenesis is considered. The history of the problem is reviewed. The author's data on reorganization of chromosome structure in germline tissue considered in terms of systemic mutations are systematized. The notion of specific morphogenetic field based on chromosome structure, which controls ooplasmic segregation and subsequent developmental stages, is developed.

[Localization of repetitive DNA sequences in the pericentromeric heterochromatin of malarial mosquitoes of the "Anopheles maculipennis" complex].

Distribution of eight fragments of conserved repetitive DNA from pericentromeric heterochromatin of chromosome 2 of Anopheles atroparvus has been investigated by in situ hybridization on polytene chromosomes of An. atroparvus and An. messeae. We have shown that heterochromatic regions of all chromosomes both in An. atroparvus and An. messeae vary in combinations of, at least, conserved repeats. Some repeats have been found only in pericentromeric heterochromatic regions of chromosomes 2 (clones Atr2R-46a, Atr2R-73, Atr2R-85a in An. atroparvus and Atr2R-25 in An. messeae). Others have been found in two (clones Atr2R-25a and Atr2R-90 in An. atroparvus, Atr2R-25a in An. messeae) and more (clones Atr2R-118, Atr2R-136 in An. atroparvus, Atr2R-73 in An. messeae) pericentromeric heterochromatic regions of chromosomes. DNA comparison of pericentromeric heterochromatic regions of chromosomes in species of the "Anopheles maculipennis" complex is species- and chromosome-specific, due, in particular, to different maintenance of conserved repeates.

[Visualization of chromosome territories in interphase nuclei of ovarian nurse cells in Calliphora erythrocephala Mg. (Diptera: Calliphoridae)].

Analysis of localization of chromosomes 2, 3, and 6 of Calliphora erythrocephala Mg. in ovarian nurse cell nuclei with different chromatin structure has shown that the regions of DNA probe hybridization reduced with increasing chromatin compaction. Hybridization of DNA probes of chromosomes 3 and 6 to secondary reticular nuclei demonstrated that chromosomes retain their territories in the nuclei when the chromatin acquires a reticular structure. These results suggest regular organization of the chromosomal apparatus at all stages of the endomitotic cycle, including the stage of highly polyploid reticular nuclei. FISH of DNA probe of the chromosome 2 telomeric region to secondary reticular nuclei revealed a peripheral distribution of the signal. Zones of more intensive DNA probe hybridization have been distinguished. These zones probably are the regions of accumulation of telomeric and (or) centromeric chromosome regions.