Pairs Of Meta Research Articles

Characteristics of the karyotype of Ukrainian buffalos

The article presents the results of studying the karyotype of the Ukrainian buffalo population. With the help of routine and GTG methods of analysis of metaphase plates of chromosomes, it was established that in the studied animals the diploid chromosome set was equal to fifty chromosomes (2n=50), which consisted of 5 pairs of meta- and submetacentric and 19 pairs of acrocentric autosomes and one pair (XX) or (XY) sex chromosomes. The total number of chromosome arms (FN) was 60, which correspond to animals of the water buffalo species (Bubalus bubalis), a subspecies of the river buffalo (B. b. Bubalis). Cytogenetic control revealed wide intraspecies limits of spontaneous somatic mutagenesis: absence of constitutive chromosomal disorders; the frequency of metaphases with aneuploidy, the average value (M±m) of which was equal to 10.5±0.13%, polyploidy (M±m=0.7±0.25%), asynchronous separation of the centromeric regions of chromosomes - (M±m=5.3±2.00), chromosomal breaks (M±m=0.7±0.24%), the proportion of cells with micronuclei (M±m=2.5±0.39‰), binucleated cells (M±m=2.6±0.32‰) and mitotic index (M±m=4.8±0.65‰). It has been established that Ukrainian river buffaloes are characterized by high karyotype stability.

Features of the chromosome set of representatives of smoothnosed bats of the North Caucasus

Aim. The aim of this work was to study the chromosome set of some representatives of smooth-nosed bats of the North Caucasus.Material and Methods. Various research methods were used to achieve this goal, including that of dried preparations (the main method for obtaining chromosomal preparations) and that of constructing karyograms.Results. A comparative analysis of the karyological data of 11 species of smooth-nosed bats of the North Caucasus was undertaken and the karyological characteristics of the species accepted in the latest reports on the fauna of Russia and the Caucasus were clarified. The similarity of G -bands in large pairs of meta- and submetacentric chromosomes in Myotis blythi, Myotis mystacinus, Pipistrellus pipistrellus, Pipistrellus kuhli and Vepertilio murinus with bands in small and medium-sized acrocentric chromosomes such as in Eptesicus seotinus may indicate the evolution of the karyotype of the first species by Robertsonian translocation, i.e. compounds of acrocentric chromosomes of Eptesicus serotinus in various combinations. When comparing karyotypes in the family Vespertilionidae, it was found that the karyotype of Eptesicus serotinus is "archaic" (2n=50, NFa=48). With the help of karyological data, the authors composed schemes of phylogenetic relationships of genera in the family Vespertilionidae, which differ to a certain extent from the schemes compiled by taxonomists for representatives of this family.Conclusions. Based on the results obtained, we can conclude that the karyotype of Eptesicus serotinus is the most primitive among the representatives of the order of bats. The primary role in the evolution of this group was played by Robertsonian rearrangements and pericentric inversions (reduction of NFa and 2n from 50 to 38).

Karyotypes of two rare rodents, Hapalomys delacouri and Typhlomys cinereus (Mammalia, Rodentia), from Vietnam

Karyotypes of Hapalomys delacouri (Rodentia, Muridae) and Typhlomys cinereus (Rodentia, Platacanthomyidae) from Vietnam are described for the first time. The diploid karyotype of Hapalomys delacouri is 38 (NFa=48), consisting of six pairs of bi-armed and 12 pairs of acrocentric autosomes decreasing in size; plus a large metacentric X chromosome and Y chromosome, also metacentric, that is equal in size to the largest pair of acrocentric autosomes. The newly described karyotype differs significantly from that reported for Hapalomys delacouri from northern Thailand. The latter record very likely represents a different species of Hapalomys, possibly the taxon Hapalomys pasquieri described from north-central Laos.The diploid karyotype of Typhlomys cinereus is 38 (NF=48), consisting of five pairs of meta- to submetacentric and 14 pairs of acrocentric chromosomes varying in size from large to small; sex chromosomes were not defined.

Karyotype of the anadromous whitefish Coregonus lavaretus pidschian (Gmelin, 1788) from the Northern Dvina River (White Sea Basin)

The karyotype of anadromous whitefish from the Northern Dvina River was examined. The chromosomal complement consists of 9 pairs of biarmed chromosomes (8 pairs of meta- and 1 pair of submetacentrics) and 31 pairs of uniarmed (subtelo- and acrocentric) chromosomes, 2n=80, NF=98. The variability in the length of metacentrics of the first pair and the number of B-chromosomes was found.

A large βzzz of π-extended molecules tetra-substituted by meta-positioned donor–acceptor pairs

We computationally studied hyperpolarizability β of C 2v fused-ring molecules substituted by two pairs of meta- or para-positioned donor (D)–acceptor (A). In two types of meta-substituted isomers, the meta1-type showed small β zzz , being plausible since the meta-positioned D–A pairs indicated the resonance structures not preferable for the large charge transfer (CT). Nevertheless, the meta2-type showed a large β zzz resulting from a large forward CT associated with the HOMO–LUMO transition. This β zzz increased with the number of fused-rings (the x-extension) and decreased slightly with small structural changes by the geometry optimization, but these changes did not vary the dominant CT structure. The x-extension was ineffective to the large β zzz for the para-substituted isomer.

Lower Bounds to Hammett σ Constants for meta and para Normal Substituents

Twenty-four pairs of meta and para Hammett σ constants recommended by IUPAC for normal substituents, i.e. dipolar groups without a lone pair of electrons (and with a full octet) in the atom next to the aromatic ring, were analysed with respect to their meta-para interrelationship. In terms of a previous hyperbolic model, the para/meta ratio of the universal electric effect is found to be 0.964 with a standard error of 0.028 estimated by Monte Carlo simulation. This value for benzoic acid derivatives supports the view that the universal electric effect, which is proposed to be termed the Electra effect, is transmitted through space. For normal substituents, it is demonstrated that the hyperbolic model predicts lower bounding values of σm and σp constants. It is proposed that organometallic substituents in which a metallic atom is bounded to the α carbon should not be considered as normal substituents. It is asserted that no normal substituent should exist for which either σm is less than -0.1 or σp is less than -0.3 in the Hammett σ scale.

Chromosomes of the Funnel-web Spider Agelena limbata(Araneae: Agelenidae).

The number of chromosomes of the funnel-web spider Agelena limbata is reported to be 2n=42 (40+X1X2) in males and 44 (40+X1X1X2X2) in females based on the observation of three populations from western Honshu, Japan. These numbers do not conform to those reported by SUZUKI (1954) where the diploid number in male was interpreted as 44 (42+X1X2). The disharmony in chromosome number between the two results may be attributable to the possible miscounting in SUZUKI's observation. Unlike previous reports on chromosomes of Agelena and most of other genera of spiders, A. limbata was shown to have some pairs of meta- or submetacentrics in its karyotype.

On the karyology of trematodes of the genus Microphallus and their intermediate gastropod host, Littorina saxatilis II. Karyological study of Littorina saxatilis (Gastropoda: Prosobranchia)

The karyotypes of Littorina saxatilis Olivi specimens from exposed areas of the Yarnyshnaya inlet littoral (the Kola Peninsular, USSR) consist of 34 chromosomes, i.e. 10 pairs of meta- and submetacentrics and 7 pairs of subtelo- and telocentrics. Two pairs of bi-armed homologues are much bigger than the others. On the whole these karyotypes are similar to those of the individuals from the Swedish and English populations.

Sister chromatid exchange points in the heterochromatin and euchromatin regions of Chinese hedgehog chromosomes

The Chinese hedgehog has a diploid chromosome number of 48 in which there are eleven pairs of telo- or subtelocentric autosomes, twelve pairs of meta- or submetacentric autosomes, a metacentric X chromosome and a telocentric Y chromosome. The heterochromatin is almost completely distributed in five large distal segments of chromosomes nos. 9 to 12 and no. 18. There is no positive C-band in the centromeres of the chromosomes except for the X chromosome which has a small, weakly stained C-band in the centromere. In Chinese hedgehog cells 52.1% of SCEs are found at the junction between the euchromatin and the heterochromatin, 39.5% in the heterochromatin and 8.4% in the auchromatin. The SCE number per unit C-band is double the SCE number per unit euchromatin. The SCE rate in the heterochromatin or euchromatin regions is not proportional to their chromosome length and can be quite different between different pairs of the chromosomes. Our results indicate that there is a non-uniform distribution of the SCEs in the Chinese hedgehog cells.

Karyotype and banding analyses of Oryzias celebensis (Oryziatidae, Pisces) in cultured cells.

With the fin-culture technique, detailed karyotype studies were undertaken in Oryzias celebensis, particularly following C-banding and silver staining procedures. The chromosome number was 36 in diploid consisting of 4 pairs of meta-, 2 pairs of submeta-, and 12 pairs of acrocentrics (NF=48). The “large” biarmed chromosomes seemed to be produced by the mechanism of Robertsonian fusion. The smaller submetacentric pair consisted of satellited chromosomes with NORs on their satellited regions. Four meta- and submetacentric pairs showed characteristic C-bands on their short arms.

Mechanism of gas-liquid chromatographic separation of disubstituted benzene isomers using nematic liquid phases

From measurement and analysis of specific retention volumes of four pairs of meta and para isomers at four well controlled temperatures in the liquid-crystalline stationary phase p, p′-dihexoxyazoxybenzene, precise solute free energy, enthalpy and entropy parameters are obtained. It is found that the para isomer is more soluble and is retained longer, due to its more favorable excess enthalpy and enthalpy of solution. This behavior is interpreted in the light of current theories of nematic solutions, and a plausible separation mechanism is proposed. The extent to which this mechanism may be extended to other geometric isomers is discussed.