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Biomedical subjects

S V Mironov

Publications and source records attributed to S V Mironov.

13 recordsLinked to original sources
PubMed2001

Phylogeny of feather mite subfamily Avenzoariinae (Acari: Analgoidea: Avenzoariidae) inferred from combined analyses of molecular and morphological data.

Phylogenetic relationships among feather mites of the subfamily Avenzoariinae (Acari: Analgoidea: Avenzoariidae) were reconstructed by parsimony analysis of a combined data matrix. We analyzed 41 morphological characters and 246 molecular characters from a fragment of the 16S rDNA. Morphological trees were well supported at deep branches (genera and above), but showed much less support and resolution within genera. Molecular analyses produced trees with better resolution and support on terminal branches and worse support on basal branches. I(MF) index for the combined matrix pointed to the significant congruence of both data subsets with the whole of the data. The topology of the combined tree was close to the morphological tree in the deep branches and had well-resolved terminal branches as in the molecular tree. This suggests a considerable level of complimentarity between the two data sets. An analysis of association patterns of the mites and their hosts was conducted based on the results of the combined analyses for the Avenzoariinae and a phylogeny of their charadriiform hosts (compiled from various bird phylogeny hypotheses). The trees could be reconciled by the invoking of 12-13 cospeciation events, 6-7 duplications, 2 host shifts, and 26-29 sorting events. This suggests a high degree of cospeciation.

Animals↗
PubMed2000

New feather mite species of the family pteronyssidae (Astigmata: Analgoidea) from South African passerines (Aves: Passeriformes).

Four new species of feather mites belonging to three different genera of the family Pteronyssidae are described from passerine birds of South Africa: Pteroherpus africanus sp. n. from the garden bulbul Pycnonotus barbatus (Desfontaines) (Pycnonotidae), Pteroherpus cysticolae sp. n. from the wing-snapped cisticola Cisticola ayresii Hartlaub (Sylviidae), Pteronyssoides promeropis sp. n. from the Gurney's sugarbird Promerops gurneyi Verreaux (Promeropidae), and Sturnotrogus creatophorae sp. n. from the wattled starling Creatophora cinerea Menschen (Sturnidae). A brief review of recent publications on the taxonomy of the family Pteronyssidae is given.

Animals↗
PubMed2000

[Effect of prenatal emotional-pain stress on the status of interphase chromatin in neurons of the rat developing brain with various excitation of the nervous system].

A short-term emotional-painful stress, experienced by pregnant rat females differing in threshold of excitability of their nervous system, was used to assess the state of interphase condensed chromatin and C-heterochromatin of neuron nuclei in developing brains of 16-17 day old embryos. To reveal relationships between the genetically determined excitability of rats and the state of interphase chromatin in their neuron nuclei a computer information system has been used that enabled us to classify the neuronal nuclei according to their specific DNA image cytometry features. The results indicate an obvious relationship between excitability of the nervous system and structural-functional state of the neuronal interphase chromatin.

Animals↗
PubMed1999

[An information system for automated cytogenetic image processing: analysis of interphase chromatin of nerve cells of embryonic brain of rats with varying nervous system excitability].

To reveal a relationship between the genetically determined excitability of rats and the structural-functional chromosome organization in their neurone nuclei a computer information system has been developed to classify the neurone nuclei according to their specific DNA image cytometry features. The nuclear features, such as size, shape, and DNA content, are calculated, along with features describing characteristics of chromatin with the nucleus. The neural and glial cells are separated according to the rule based expert system approach with the use of a nuclear feature vector. The DNA image processing is performed and a feature vector consisting of normalized measures of the neurone nucleus chromatin region descriptors is extracted. The results indicate a relationship between the peculiarities of the nervous system and the structural-functional state of the chromosomal apparatus.

Animals↗
PubMed1998

[The model of adaptive primary image processing].

A computer model of adaptive segmentation of the 2D visual objects was developed. Primary image descriptions are realised via spatial frequency filters and feature detectors performing as self-organised mechanisms. Simulation of the control processes related to attention, lateral, frequency-selective and cross-orientation inhibition, determines the adaptive image processing.

Models, Neurological↗
PubMedDate not supplied

A model of adaptive visual processes of primary image processing.

A computer model of adaptive segmentation of two-dimensional visual objects was developed, based on neurophysiological and psychophysiological principles. The model imitates several stages of visual information processing. At the first stage, a preliminary assessment of the image is performed using a brightness pattern analyzer. At the second stage, control parameters are formed on the bases of the initial assessment. A defined control vector is synthesized for each type of starting image, which allows adaptive processing; this initiates two parallel mechanisms of primary image description: one contains the outlines of images and the sharp boundaries between their fragments, and the second contains areas of uniform intensity. The control parameter vector is applied to these two descriptions to analyze their brightnesses and spatial characteristics, and this is used as the basis for forming the regime for subsequent processing, which includes a set of processing operators whose parameters are tuned for each fragment of the image. The primary phasic and tonic descriptions are then used to extract individual fragments of the image (i.e., discrimination of figures from the background) and to form the final presentation. The resulting descriptions complement each other, creating a basis for quantitative measurements of image characteristics and allowing various signs needed for image classification to be formed. The computer program for adaptive image segmentation was tested using a large number of different two-dimensional half-tone objects, the purposes of these exercises including segmentation and measurement of objects in morphometric and cytometric studies.

Adaptation, Physiological↗
PubMedDate not supplied

[Seasonal dynamics of population of the feather mite Monojoubertia microphylla (Astigmata: Analgoidea: Proctophyllodidae) in the chaffinch Fringilla coelebs].

The seasonal dynamics of the Monojoubertia microphylla micropopulations in different sex and age groups of the chaffinch Fringilla coelebs (Passeriformes: Fringillidae) have been studied during the nest and migration periods in the North-West of Russia. Three bird groups were determined within the chaffinch population during the study: adult males, adult females, immature chaffinches. Total number of bird specimens examined--353. In all chaffinch groups, the mean mite numbers and age structure of mite micropopulations were similar during the spring migration. The number of mites gradually increased from April to May. During the nest and autumn migration periods the seasonal dynamics of M. microphylla micropopulations were quite different on adult males and females of the chaffinch, because of different roles of male and female in the process of infestation the young bird generation. On the adult chaffinch males, the mite number continued to increase during the breeding period (June) and began to decrease significantly in July because of the postbreeding plumage moult. The mite number slowly decreased in the end of summer and the autumn migration. On the adult chaffinch females, the mite number decreased abruptly during the nest period. During this period, the chaffinch female sits together with nestlings for a long time, and the great number of its mites (about 60% of mite micropopulation) moves from the female onto the nestlings. The mite micropopulation migrated onto nestling is represented mainly by males, females (about 25% each) and tritonymphs (38%). Total mite number on the chaffinch females continued to decrease in July under the influence of postbreeding moult and slightly increased up to the autumn migration only. On the young chaffinches, the number of M. microphylla quickly increased during the second part of summer. It is the result of the great quota of mite instars being ready for the reproduction (imago, tritonymphs) within the micropopulation migrated from the chaffinch female onto the nestlings. The decrease of the M. microphylla micropopulation on the young birds was observed in the autumn only. In the end autumn migration (October), the mean numbers of mites on all chaffinch groups became approximately similar, but did not reach the mean rate observed in the beginning of the spring migration. During both migration periods, the imago and all preimaginal instars of M. microphylla were active, the diapause was not observed. In the beginning of spring migration and the end of autumn migration the main part of the mite micropopulations was represented by females, while in all other periods of chaffinch's stay in the North-West of Russia the immature instars predominated.

Animals↗
PubMedDate not supplied

[High prevalence and diversity of blood parasites of passerine birds in Southern Turkmenistan].

Thirty nine specimens of passerine birds belonging to 19 species and eight families were investigated by blood smear technique in four localities of Southern Turkmenistan in 3-18 August 1991. The overall prevalence of infection was 59%. Protists from the orders Haemosporida (genera Haemoproteus, Plasmodium, Leucocytozoon), Kinetoplastida (Trypanosoma), and Adeleida (Hepatozoon), as well as Microfilaria were found. Haemoproteids (the prevalence of infection is 44%), leucocytozoids (23%), malarial parasites (13%) and trypanosomes (13%) were most frequently recorded. Only low chronic infections (< 1% of infected cells for the great majority of intracellular parasites, and a few trypanosomes and Microfilaria in each blood smear) were seen. Haemoproteus belopolskyi, H. balmorali, H. dolniki, H. magnus, H. minutus, H. fringillae, H. majoris, Leucocytozoon dubreuili, and Trypanosoma avium were recorded for the first time in Turkmenistan. The former five above-mentioned species of haemoproteids are new records for the fauna of Middle Asia. Gametocytes of leucocytozoids in fusiform host cells were found for the first time in passerine birds in the Holarctic. The host is Parus bokharensis. Due to the wide distribution and the opportunity to collect a large parasitological material using harmless for hosts methods, bird haemosporidian parasites can be used as convenient models for ecological and evolutionary biology studies in South Turkmenistan. The heavily infected Orphean Warbler Sylvia hortensis is an especially convenient host for such purposes.

Animals↗
PubMedDate not supplied

[The first find of the feather mite from Apionacaridae family (Astigmata: Analgoidea) on the passerines ( Passeriformes)].

A representative of the family Apionacaridae is recorded from the passerine birds Passeriformes for the first time. Fringillosphaera bochkovi gen. n., sp. n. is described from the chaffinch Fringilla coelebs (Fringillidae). The new genus obtains main diagnostic characters as follows. Vertical setae vi absent. Prodorsal shield free from scapular sheilds and epimerites Ia. Humeral sheilds present. Epimerites I convergent, connected by sclerotized plate. Lateral setae f2 and pseudanal setae ps3 absent. Coxal fields I-IV sclerotized. In male: legs IV present, genital apparatus at level of trochanters IV, genital arch with divergent branches. Epiandrium absent. Coxal setae 3a absent. Morphological peculiarities, host associations and phylogenetic relationships of the family Apionacaridae are briefly discussed. It is suggested that this family represents and ancient and relic phylogenetic branch, which had split rather early from the common ancestor of the superfamily Analgoidea in the period of formation of the Neognathae birds.

Animals↗
PubMedDate not supplied

[Taxonomy of ticks of the genus Microtimyobia (Acariformes: Myobiidae: Radfordia) and their distribution on voles (Rodentia: Cricetidae: Arvicolinae)].

A phylogenetic system of the subgenus Microtimyobia (Myobiidae: Radfordia) elaborated for the first time by means of the software HENNIG-86 is proposed. The subgenus Microtimyobia including three species groups, lemnina, hylandi and zibethicalis, was divided for a cladistic analysis into 6 operation units based mainly on a male genital shield structure. The analysis shows, that the zibethicalis group is a polyphyletic, while the hylandi and lemnina groups are monophyletic. Host-parasite associations of myobiid mite taxa with vole taxa (Arvicolinae) and some peculiarities of mite and host taxa distribution are analysed. The zibethicalis group is represented by two species, associated with the North American rodents of the genera Ondatra and Phenacomys respectively. The hylandi group are most widely distributed among Arvicolinae taxa, both in Eurasia and North America. However, R. hylandi occurs on those vole species of the genera Microtus and Pitymys, which are distributed only in central and southern parts of North America and represent descendants of the earlier migration wave of Microtus from the Eurasia. As far as R. hylandi is also found in the pleistocenus of the Yakutia, that means that its areal was wider than in recent period. The lemnina group lives on hosts of 2 subtribes of the tribe Arvicolini (Arvicolina and Clethrionomyina) and is restricted to Eurasian range, except R. lemnina. This species is also mainly distributed on Eurasian vole species, however it occurs on vole species distributed in Alaska and being decendants of the later wave of Microtus migration. As far as R. lemnina and R. hylandi are associated with representatives of different migration waves of Microtus from the Euroasia, it is suggested that mites of the hylandi group are the original myobiid fauna of the Microtus voles. The species of the lemnina group had apparently originated on voles of the subtribe Clethrionomyina and then migrated onto phylogenetically young hosts of the subtribe Arvicolina (Euroasian species of the Microtus and related genera), where they probably eliminated mites of the hylandi group from these hosts in Euroasia. The recent pattern of myobiid species distribution on vole species is a result of both a mite cospeciation with their hosts and a shift of hosts. Five new myobiid mite species are described and distinguished by characters as follows. R. (M.) abramovi sp. n. from Phodopus roborovskii (Cricetidae) is closely related to R. (M.) triton Fain et Lukoschus, 1977. In both sexes of the new species setae cxI 1, 2 are scale-shaped, while in R. (M.) triton these setae (cxI 1, 2) are hair-like. R. (M.) stekolnikovi sp. n. from Chionomys nivalis (type host) and Ch. gud is similar to R. (M.) lemnina (Koch, 1841). Females of new species have setae ra with 2 apical processes; female tritonymphs with long whip-like setae ic4. R. (M.) lemnina females have setae ra with 3 processes; female tritonymphs with short hair-like setae ic4. R. (M.) stenocrani sp. n. from Microtus gregalis is also closely related to R. (M.) lemnina. Females of the new species have setae ra with 2 processes; female tritonymphs with whip-like setae ic3. R. (M.) lemnina females have seate ra with 3 processes, female tritonymph with short hair-like setae ic3. R. (M.) synaptomysi sp. n. (ABSTRACT TRUNCATED)

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