Search

Urolithiasis is one of the most urgent problems of clinical urology. Currently, there is no consensus on the causes of stone formation, as well as the role of various factors in the development of urolithiasis, however, increasingly, according to various studies, the leading role is given to genetic causes. The article presents a modern review of data on genetic polymorphisms associated with ICD: rs1801197 and rs6776158 of the CASR gene; TaqI of the VDR gene; rs1801197 of the CALCR gene, rs3752472, rs650439, rs2853744 of the Klotho gene.

Using fluorescence methods for visualization of human tumor cell apoptosis and necrosis in vitro, the antitumor effects of flavonoid-containing Gratiola officinalis L. and green tea extracts at ultralow concentrations on A498 human kidney carcinoma cells after 24 and 48 h were compared. Fluorescent dyes (propidium iodide and acridine orange) were used in the “living and dead” test, which made it possible to identify the total number of cells that died by necrosis and apoptosis, as well as cells in which apoptosis has started and apoptotic bodies or pycnosis of the nucleus were detected. Gratiola officinalis L. extract had the most pronounced cytostatic activity 48 h after exposure; the number of cells per field of view decreased by a factor of 1.5 compared with the control. Green tea extract at a concentration of 0.0288 mg/mL had the most pronounced cytotoxic activity; its manifestation was growing 48 h after exposure. Gratiola officinalis L. extract exhibited cytotoxic activity at lower concentrations (0.0036 mg/mL).

The quercetin content in aqueous EtOH extracts of covering leaves of anthocyanin Purple Saratov diploid variety of Zea mays L. grown under dry conditions reached 39.36 ± 0.41 mg/100 g of dry extract and significantly exceeded the value (26.03 ± 0.36 mg/100 g of dry extract) for maize grown under normal wetting conditions. The large amounts of polyphenolic compounds in anthocyanin Purple Saratov diploid variety showed good prospects for using it as a source of them.

The possibilities of using fluorescence-based analytical methods and their advantages for visualization and identification of the type of programmed cell death in human tumor cells exposed to flavonoids have been analyzed in experiments in vitro. HeLa cervical cancer cells and A498 kidney carcinoma cells were used as the objects of the study, and exposure to the flavonoid-containing extract of common hedgehyssop (Gratiola officinalis L.) was tested as the experimental treatment. The following fluorescence-based techniques were used: the “live and dead” test with double staining by propidium iodide and acridine orange and double staining with annexin and propidium iodide. Autophagy induction was confirmed by fluorescence-based tests implemented in a Muse cell analyzer with a Muse Autophagy LC3-Antibody Based Kit. The use of double staining with acridine orange and propidium iodide fluorescent dyes in the “live and dead” test and comparison with phase contrast microscopy enables the visualization of apoptotic body and autophagosome formation processes in the cells and can, therefore, be used as a method of screening assessment of the efficiency of various chemotherapy drugs.

The chemical composition of a new bioactive extract from immortelle sandy (Helichrysum arenarium (L.) Moench.) was investigated. Naringin, its soluble aggregate, prunin, quercetin, apigenin, naringenin, apigenin 5-O-glucoside, and isosalipurposide were found among the flavonoids. The tested immortelle sandy extract was shown to contain known dimers, trimers, or more complex aggregates. The compounds had similar spectral but substantially different chromatographic characteristics, which can be used for their identification based on the corresponding data on flavonoids glycosylated at different positions and/or carbohydrates of various complexities, which are also characterized by similar absorption spectra and different retention times. It was found by molecular absorption spectroscopy that the immortelle extract contained 73.48 mg of flavonoids relative to rutin or 17.94 mg relative to quercetin per 1 g of dry extract weight, which corresponded to 20.99 and 5.13%, respectively. The immortelle extract obtained by the method proposed displayed antitumor activity against the transplanted sarcoma 45 and had a beneficial effect on animals in general.

To establish the mechanisms of pathomorphism of transplantable kidney cancer in rats that used flavonoid-containing hedge hyssop (Gratiola officinalis L.) extract in an in vivo experiments.The experiment was carried out on 30 male Wistar rats with transplantable kidney cancer PA. At 72 hours after tumor inoculation, the rats in the experimental groups received hedge hyssop extract at an oral or intramuscular dose of 110 mg/kg/day for 12 days. A comparison group consisted of the animals with a tumor, but without exposure. The investigators used the immunohistochemical markers of apoptosis (p53, bax, bcl-2, Fas-receptor, Fas-ligand), autophagy (LC3B), proliferation (Ki-67), and angiogenesis (VEGF). During statistical data processing, the Shapiro-Wilk test was used to test the normality of the indicator distribution in the groups. Cramer-Welch's t-test was also employed to compare the groups.Histological examination of tumor tissue under the action of hedge hyssop extract showed the emergence of extensive areas of damage (necrosis and apoptotic bodies). With both routes of hedge hyssop extract administration, there was a sharp decrease in the expression of the proliferation markers Ki-67 and the angiogenesis marker VEGF and a high expression of the apoptosis markers p53, bax, CD95 (Fas/APO-1), and FAS-ligand in tumor cells and its absence in the comparison group. All the described changes were more pronounced with intramuscular administration. The expression of the autophagy marker LC3B increased with the oral administration of hedge hyssop extract and decreased with its intramuscular administration.A pronounced pathomorphism of kidney cancer develops due to consumption of hedge hyssop extract. This suppresses the proliferation, angiogenesis, and activation of apoptotic signaling and mitochondrial pathways and blocks protective autophagy. The autophagy marker LC3B can be used as an additional criterion for evaluating the therapeutic pathomorphism of tumors.Цель исследования - в экспериментах in vivo установить механизмы патоморфоза перевитого рака почки под влиянием флавоноидсодержащего экстракта аврана. Материал и методы. Эксперимент проводили на 30 самцах крыс Wistar c перевитым раком почки РА. В опытных группах крысы через 72 ч после перевивки опухоли на протяжении 12 сут получали экстракт аврана перорально или внутримышечно в дозе 110 мг/кг/сут. Группу сравнения составили животные с опухолью, но без воздействия. Использовали иммуногистохимические маркеры апоптоза (p53, bax, bcl-2, Fas-receptor, Fas-ligand), аутофагии LС3b, пролиферации Ki-67 и ангиогенеза VEGF. При статистической обработке данных нормальность распределения показателей в группах проверяли при помощи критерия Шапиро-Уилка. Для сравнения групп использовали критерий Крамера-Уэлча (Т). Результаты. При гистологическом исследовании в ткани опухоли под действием экстракта аврана наблюдали появление обширных зон повреждения (некроз и апоптозные тельца). При обоих путях введения экстракта аврана отмечали резкое снижение экспрессии маркеров пролиферации (Ki-67), ангиогенеза (VEGF) и высокую экспрессию маркеров апоптоза (p53, bax, CD95 (Fas/APO-1), FAS-ligand) в опухолевых клетках и отсутствие ее в группе сравнения. Все описанные изменения были более выражены при внутримышечном введении. Экспрессия маркера аутофагии LC3B увеличивалась при пероральном и уменьшалась при внутримышечном введении экстракта аврана. Заключение. Под влиянием экстракта аврана развивается выраженный патоморфоз рака почки. Происходят подавление пролиферации, ангиогенеза и активация сигнального и митохондриального пути апоптоза, а также блокирование протекторной аутофагии. Маркер аутофагии LC3b может использоваться в качестве дополнительного критерия оценки лечебного патоморфоза опухолей.

Substance flow across the water–air boundary on the floodplain Lake Holodnoe (Saratov oblast) is generally formed by the Culicomorpha (76.1%) and accounts for 0.35 g/m2 of the lake area per year. The energy flow amounts to 1.87 kcal/m2, and most of it accounts for the second half of summer and autumn. Annual removal of biogenic elements is 0.18 g/m2 for carbon, 0.04 g/m2 for nitrogen, and 0.004 g/m2 for phosphorus. The greatest contribution to flows of substance and energy is brought by large species of chironomids, as well as chaoborids and medium-sized chironomids, which produce several generations within a year and reach high abundance at a larval stage. Other floodplain lakes of the Volga River with similar biotopical features and species composition of amphibiotic insects are characterized by a quantitatively similar level of exchange processes with adjacent land ecosystems across the water–air boundary.

This study focuses on the effect of the flavonoid-containing Gratiola officinalis L. extract with antitumor activity on the intensity of peroxidation and the content of vitamin E in the blood serum of animals with transplanted liver cancer PC-1. Intramuscular and oral administrations of the Gratiola officinalis extract in a dose of 110 mg/kg reduce MDA concentration (more than 20 times) and lipid hydroperoxide (more than 1.5 times) in rats with transplanted tumors. This effect leads to decrease in intensity of lipid peroxidation processes in animals. The Gratiola officinalis extract administration increases the vitamin E concentration (more than 1.3 times) in the serum of rats. This result enables to suggest that the extract of Gratiola officinalis contains the tocopherols. Thus, the study of mechanisms of the Gratiola officinalis extract influence on the activity of peroxidation processes and on the activation of the antioxidant system is promising.

The karyotype of Camptochironomus tentans (Fabricius), 1805 (Diptera, Chironomidae) from the populations of the Lower Volga region and Central Caucasus (the northern macroslope) has been studied. In the karyotype of C. tentans from Saratov oblast, 14 banding sequences (BS), 13 genotypic combinations, and 14 zygotic combinations were identified. Four new BSs were described: ten B12, ten F4, ten F5, and ten G4, which are distinguished by simple paracentric inversions from those already known for the species. The chromosomal polymorphism belongs to the inversion type; its level in the Saratov population is generally the same as in populations of other parts of the area. The number of heterozygous inversions per specimen was 1.3; the number of heterozygous inversions per arm was 0.86; the percentage of heterozygous larvae was 84.5. The polymorphic arms in C. tentans were A, B, C, and F. Nine previously known BSs were revealed in the karyotype of C. tentans from Central Caucasus, and no new sequences were found. Arm B in C. tentans was polymorphic. The zygotic combinations in all the studied populations were distinct.

The karyotype of Camptochironomus pallidivittatus Edwards, 1929 (Diptera, Chironomidae) from six populations of the Lower Volga region and Central Caucasus (the northern macroslope) has been studied. In populations of C. pallidivittatus from the Central Caucasus, 11 banding sequences (BS) were found; one sequence, pal B10, was new for the species. In the Saratov population, 11 BS were also found, three of which were new for the species-pal A3, pal B11, and pal B12. The banding sequences detected for the first time have not yet been found in other parts of the area of this species and may be endemic to these regions. In the studied populations of C. pallidivittatus, banding sequences were found that were non standard, but fixed in the karyotype. This is indicative of some degree of chromosomal divergence. These banding sequences include pal A2.2 in arm A and pal B10.10 in arm B in the Central Caucasus region, as well as pal B2.2 and pal G2.2 in the Lower Volga region. Arms A, B, D, and G in the Central Caucasian populations and A, B, and D in the Saratov oblast were polymorphic. The composition of heterozygous sequences between populations from different regions coincided only in arm D (pal D1.2). In arms A and B, the set of heterozygous BS was different: pal A1.2 and pal B1.10 sequences were found in the Central Caucasian populations, and pal A1.3 and B11.12 were found in Saratov oblast. The number of genotypic combinations of C. pallidivittatus was higher in the Central Caucasus region, whereas the number of zygotic combinations was higher in the Saratov population. The percentage of heterozygous larvae in the Central Caucasian populations varied from 20 to 80, whereas all individuals in the Saratov population had heterozygous inversions. Zygotic combinations of larvae in all the studied populations were different.

Influence of flavonoids on the intensity of peroxidation processes in the blood is investigated by numerical modeling and by experiment in vivo. As an example we consider the effects of flavonoid-containing extract of Helichrysum arenarium L. with antitumor activity on serum of rats with transplanted liver cancer PC-1. It was found that the content of malondialdehyde, lipid hydroperoxides and average mass molecules were decreased in animals with transplanted liver cancer after intramuscular and oral administration of Helichrysum arenarium L extract in a dose of 1000 mg/mL. The extract reduces the intensity of lipid peroxidation processes in animals. The compound formation possibility of flavonoids and products of lipid peroxidation is investigated by numerical simulations. Using the density functional theory method of molecular modeling, we analyze hydrogen bonds formation and their influence on IR - spectra and structure of molecular complex which is formed due to interaction between flavonoids and products of lipid peroxidation processes on example of naringine and malondialdehyde. We have found that naringine can form a steady molecular complex with malondialdehyde by hydrogen bonds formation. Thus, the application of Helichrysum arenarium L. extract for suppression processes of lipid peroxidation and activation of enzymatic and non-enzymatic antioxidant systems is promising.

The nucleotide sequences of the mtDNA cytochrome oxidase I (COI) gene fragment 535 bp long (pos. 100 to 634) in 14 midge species (Diptera, Chironomidae): Dicrotendipes nervosus, Endochironomus albipennis, E. tendens, Glyptotendipes barbipes, G. glaucus, G. gripekoveni, G. imbecillis, G. mancunianus, Polypedilum sordens, Stenochironomus gibbus, Synendotendipes kaluginae, Xenochironomus xenolabus, Xenochironomus sp., Cricotopus glacialis, and those of the mtDNA COII gene fragment 561 bp long (pos. 22 to 583) in 3 midge species: Chironomus plumosus, Chironomus balatonicus, and Baeotendipes noctivaga were determined. The time of gene COI divergence in the phytophilous midges of various taxa was estimated. The wood-mining species Stenochironomus gibbus belongs to the most ancient midges which diverged together with the ancestor form of two subfamilies, Chironominae and Orthocladiinae, about 104 Mya. Phytophily evolved in the midge larvae at different times in different taxa: among Chironominae, about 47.2 Mya in P. sordens, not earlier than 20 Mya in Glyptotendipes, Kiefferulus, and Dicrotendipes, and not earlier than 13 Mya in Endochironomus albipennis; among Orthocladiinae, 19 Mya in Cricotopus. The divergence of the genera containing phytophilous and fouling species, both in Chironominae (Dicrotendipes, Glyptotendipes, Kiefferulus) and Orthocladiinae (Orthocladius and Cricotopus), occurred approximately 20 Mya, and coincided with the beginning of formation of the recent-type limnofaunas 23 Mya.

Karyotype of the Chironomus nuditarsis Str. (Keyl, 1962) chironomids from central Caucasian populations located at different altitudes above the sea level (a.s.l.) was examined. Specific features of the inversion polymorphism of the high-mountain (more than 1000 m a.s.l.), foothill (500–1000 m a.s.l.), and plain (up to 500 m a.s.l.) populations were identified. A new chromosome banding sequence, ndt F2 (1g-e 7a–8c), which was endemic to Caucasian populations, was described. With the increase in the altitude of the reservoir a.s.l., the decrease in the frequency of ndt G1.2 and ndt B2.2 inversions and the number of inversions per individual and per arm was observed. In the high-mountain population, only the ndt G2.2 homozygotes were detected. The plain population is an interstitial population, while foothill and high-mountain populations are terminal. Cytogenetic distances between the high-mountain and other samples range from 0.174 to 0.223, which is higher than the mean interpopulation value for this species (0.138). The allochrony of the life cycle in aborigines larvae from the foothill population and aborigines from the high-mountain population can be caused by factors such as low high-mountain reservoir temperature. This factor increases the duration of the stages of larvae developmental, which leads to a reduced number of generations and results in a shift in the imago flight and mating timing.

In the present work the effectiveness of antioxidants quercetine (a pure chemical) and Gratiola officinalis extract, which is obtained by a new method of extraction from plant material, is investigated on the model of photodynamic haemolysis that is a rather convenient method to monitor the rate of cell membranes oxidative destruction. The effect of these antioxidants on the rate of photodynamic haemolysis is considered as a measure of membranoprotective efficiency.

This is the first study to infer the phylogenetic structure of minges of the subfamily Chironominae from the amino acid sequence of cytochrome oxidase I (COI). The subdivision of Chironominae into two tribes, Chironomini and Tanytarsini, has been confirmed. The segregation of the genera Pseudochironomus and Riethia into a separate tribe has not been confirmed. Stenochironomus gibbus forms a branch considerably deviating from the subfamily Chironominae. The genus Micropsectra is formed by a large polyphyletic cluster that also includes the genera Virgotanytharsus, Reotanytharsus, Kenopsectra, and Parapsectra. Tanytarsus is the basal genus of the tribe Tanytarsini. The times of divergence of the main taxa of Chironominae have been estimated. The calculated time of divergence of the genus Chironomus disproves the assumption that it is phylogenetically old.

The sequence of a 595-bp fragment of the mitochondrial COI gene was determined for the species Chironomus usenicus and Chironomus curabilis of the genus Chironomus. Phylogenetic reconstructions based on the analysis of the COI gene sequence coincide on the whole with cytogenetic data, permitting Ch. usenicus and Ch. curabilis to be regarded as members of the group plumosus. Chironomus usenicus and Ch. plumosus have identical COI gene sequences. Two hypotheses explaining this identity are considered: inheritance of mtDNA from one of the parental species during hybridogenesis and horizontal transfer of mitochondrial genes.

Bacteriostatic and bactericidal activity of aqueous solution (50 mg/mL) of alcoholic extract of Helichrýsum arenárium (L.) dried flowers, prepared by a special technique so as to increase the yield of flavonoids, was studied in vitro with respect to Mycobacterium tuberculosis (MBT) strains possessing varying degrees of drug resistance, as characterized by replacements Ser R Leu (modification of b-subunit RNA-polymerase of MBT) and Ser R Thr (inactivation of MBT catalase-peroxidase enzyme). The mechanism of this drug action is clearly distinguished from that of the first-line drugs, since strains resistant to these reference drugs have proved susceptible to extract H. arenárium extract. This extract can be recommended for preclinical and clinical studies in the search for new antituberculous drugs and for studying new mechanisms of drug action on MBT. It may also be an effective drug for the treatment of multidrug-resistant MBT strains.

The karyotype of Camptochironomus tentans (Fabricius), 1805 (Diptera, Chironomidae) from the populations of the Lower Volga region and Central Caucasus (the northern macroslope) has been studied. In the karyotype of C. tentans from Saratov oblast, 14 banding sequences (BS), 13 genotypic combinations, and 14 zygotic combinations were identified. Four new BSs were described: ten B12, ten F4, ten F5, and ten G4, which are distinguished by simple paracentric inversions from those already known for the species. The chromosomal polymorphism belongs to the inversion type; its level in the Saratov population is generally the same as in populations of other parts of the habitat. The number of heterozygous inversions per specimen was 1.3; the number of heterozygous inversions per arm was 0.86; the percentage of heterozygous larvae was 84.5. The polymorphic arms in C. tentans were A, B, C, and F. Nine previously known BS were revealed in the karyotype of C. tentans from Central Caucasus, and no new sequences were found. Arm B in C. tentans was polymorphic. The zygotic combinations in all the studied populations were distinct.

The extract of Gratiola officinalis L. has been obtained by an original method ensuring the maximum yield of flavonoids. The extract simultaneously exhibits high anti-inflammatory activity, selective antimicrobial properties (with respect to Staphylococcus aureus and Pseudomonas aeruginosa, but not to conditionally pathogenic E. coli) and antipyretic effect (observed for the first time in Gratiola officinalis L. preparations). Advantages of the proposed preparation are low toxicity, availability of the raw material, and broad spectrum of therapeutic effects.

Hybridogenesis as a possible way of speciation in Chironomidae was considered with special reference to the species Chironomus usenicus resulting from hybridization between C. plumosus and C. behningi. The three species had 2n = 8 and belonged to the thummi cytocomplex with chromosome arm combinations AB, CD, EF, and G. Arm G had a marker chromosome disk sequence (CDS) and was used to demonstrate the hybrid origin of C. usenicus. Most C. usenicus larvae were heterozygous in CDS of arm G. CDS use G2 proved to be identical to CDS beh G1 ofC. behningiand CDS use G1, to CDS plu G1 of C. plumosus. It was assumed that C. usenicus results from hybridization between eurybiont C. plumosus and stenobiont C. behnigni at the boundary of their species areas, in freshwater or brackish water bodies of the southern Saratov oblast and northern Kazakhstan. Morphologically and karyotypically, the hybrid was probably similar to C. plumosus. Crosses with C. plumosus eliminated virtually all C. behningi chromosome sequences from the karyotype of the hybrid. Further chromosome divergence resulting in C. usenicus involved a number of chromosome rearrangements, including duplication of pericentric heterochromatin and other chromosome regions; inversion, which occurred in arm F (regions 13–16) and was fixed in the karyotype; and other paracentric inversions and deletions accumulated in heterozygote in the karyotype pool of the species. Since C. behningi was eliminated from the introgression zone and its species area reduced, the assimilation character was assumed for introgressive hybridization of C. behningi and C. plumosus.

Karyotypes of the Chironomus nuditarsis Str. (Chironomidae, Diptera) (Keyl, 1962) chironomids from central Caucasian populations located at different altitudes above the sea level (a.s.l.) were examined. Specific features of the inversion polymorphism of the high-mountain (more than 1000 m a.s.l.), foothill (500-1000 m a.s.l.), and plain (up to 500 m a.s.l.) populations were identified. A new chromosome banding sequence, ndt F2 (lg-e 7a-8c), which was endemic to Caucasian populations, was described. With the increase in the altitude of the reservoir a.s.l., the decrease in the frequency ofndt G1.2 and ndt B2.2 inversions and the number of inversions per individual and per arm was observed. In the high-mountain population, only the ndt G2.2 homozygotes were detected. The plain population is an interstitial population, while foothill and high-mountain populations are terminal. Cytogenetic distances between the high-mountain and other samples range from 0.174 to 0.223, which is higher than the mean interpopulation value for this species (0.138). The allochrony of the life cycle in aborigines from the foothill population and aborigines from the high-mountain population can be caused by factors such as low high-mountain reservoir temperature. This factor increases the duration of the stages of larvae developmental, which leads to a reduced number of generations and results in a shift in the imago flight and mating timing.

Contemporary systematics of insects is based mainly on morphological traits. However, their usage is limited both by high variability and complications in comparisons of remote taxa due to low number of common traits. In whole, this leads to a somewhat subjective view when elaborating the system. Unlike morphological ones, molecular traits of taxa, revealed by use of marker genes such as gene cytochrome-c-oxidase I (COI), are less variable and more uniform, which allows them to be used as a criterion of genus, tribe, and subfamily for a wide range of organisms. Application of molecular criteria appears to be all the more important when constructing the system for groups of organisms with high morphological and specific diversity, such as midges (Chironomidae, Diptera). Last years, the DNA-sequence of gene COI is becoming widely used for species identification as a bar-coding one. Its use as a criterion for taxa of super-species level is hampered by its high nucleotide variability. We established the bounds of COI nucleotide and aminoacid divergence between midge species of Chironominae subfamily belonging to the same genus, same tribe, different tribes, as well as between species of Chironominae and Orthocladiinae subfamilies. It is shown that the level of aminoacid divergence reflects molecular boundaries of genus and tribe better than nucleotide one. It can be stated that if the level of aminoacid divergence falls within the limits from 0 to 1.7% then a pair of species compared belongs to the same genus; if it falls within the limits from 1.7 to 4.0% then they belong to the same tribe; within the limits from 4.6 to 6.3%--to different tribes; if it exceeds 7.9%--to different subfamilies. The accuracy of identification when using these ranges turns out to be not less than 75%. In this regard, bounds of COI sequence aminoacid divergence may be used as taxonomic criteria for midge genus, tribe or subfamily.

This is the first study to infer the phylogenetic structure of minges of the subfamily Chironominae from the amino acid sequence of cytochrome oxidase I (COI). The subdivision of Chironominae into two tribes, Chironomini and Tanytarsini, has been confirmed. The segregation of the genera Pseudochironomus and Riethia into a separate tribe has not been confirmed. Stenochironomus gibbus forms a branch considerably deviating from the subfamily Chironominae. The genus Micropsectra is formed by a large polyphyletic cluster that also includes the genera Virgotanytharsus, Reotanytharsus, Kenopsectra, and Parapsectra. Tanytarsus is the basal genus of the tribe Tanytarsini. The times of divergence of the main taxa of Chironominae have been estimated. The calculated time of divergence of the genus Chironomus disproves the assumption that it is phylogenetically old.

The sequence of a 595-bp fragment of the mitochondrial COI gene was determined for the species Chironomus usenicus and Chironomus curabilis of the genus Chironomus. Phylogenetic reconstructions based on the analysis of the COI gene sequence coincide on the whole with cytogenetic data, permitting Ch. usenicus and Ch. curabilis to be regarded as members of the group plumosus. Chironomus usenicus and Ch. plumosus have identical COI gene sequences. Two hypotheses explaining this identity are considered: inheritance of mtDNA from one of the parental species during hybridogenesis and horizontal transfer of mitochondrial genes.

Karyotype and morphology of Chironomus sp. larvae from the Caspian Sea have been described. 2n = 8. Chromosomal arm combination is AB, CD, EF, G (cytocomplex thummi). All chromosomes display conjugation of homologues. Centromere areas are of s-type. The nucleolar organizer and two Balbiani rings are disposed in arm C, and another Balbiani ring is in arm B. Half larvae have heterozygotic paracentric inversions in arm D. The larva belongs to salinarius form. One scleritis is colorless, an occipital scleritis is light and irregularly colored. Premandible has 4-5 cogs. Epipharingeal ridge has 18-23 dens. This new species is close to salinarius group, especially to Ch. albidus Konst., but differs from it at the larva stage in the structure of non-massive basal antenna segment, in the presence of large quantity of premandible denses, in light color of occipital scleritis, and in a series of morphometric rates. A similarity berween Ch. paraalbidus and Ch. albidus, on the one hand, and Boeotendipes, on the other one, has been found out.

Hybridogenesis as a possible way of speciation in Chironomidae was considered with special reference to the species Chironomus usenicus resulting from hybridization between C. plumosus and C. behningi. The three species had 2n = 8 and belonged to the thummi cytocomplex with chromosome arm combinations AB, CD, EF, and G. Arm G had a marker chromosome disk sequence (CDS) and was used to demonstrate the hybrid origin of C. usenicus. Most C. usenicus larvae were heterozygous in CDS of arm G. CDS use G2 proved to be identical to CDS beh G1 of C. behningi and CDS use G1, to CDS plu G1 of C. plumosus. It was assumed that C. usenicus results from hybridization between eurybiont C. plumosus and stenobiont C. behnigni at the boundary of their species areas, in freshwater or brackish water bodies of the southern Saratov oblast and northern Kazakhstan. Morphologically and karyotypically, the hybrid was probably similar to C. plumosus. Crosses with C. plumosus eliminated virtually all C. behningi chromosome sequences from the karyotype of the hybrid. Further chromosome divergence resulting in C. usenicus involved a number of chromosome rearrangements, including duplication of pericentric heterochromatin and other chromosome regions; inversion, which occurred in arm F (regions 13-16) and was fixed in the karyotype; and other paracentric inversions and deletions accumulated in heterozygote in the karyotype pool of the species. Since C. behningi was eliminated from the introgression zone and its species are reduced, the assimilation character was assumed for introgressive hybridization of C. behningi and C. plumosus.

The karyotype of Chironomus heterodentatus, belonging to the obtusidens-group described by Konstantinov from the Volga in 1956, was studied in detail. Combinations of chromosomal arms are AB, CD, EF and G (cytocomplex thummi). The Ch. heterodentatus karyotype cleary differs from those of other members of the obtusidens-group with a species-specific banding pattern in arms A, B, C and D. Chromosomal polymorphism on homo- and heterozygous inversions was found in arms, A, B, D, E and G. 19 inversion banding sequences and their 27 genotypic combinations have been recorded. The shortest arm G is highly polymorphic. Heterozygotes on the Balbiani ring activity were found in arm G along with homo- and heterozygotes on inversions. B-chromosomes with a frequency equal to 2.7-25.0% were recorded in some Volga populations.