Evolutionary and climatic factors affecting tooth size in the red foxVulpes vulpes in the Holarctic

Research into the geographical pattern of tooth size in the red fox,Vulpes vulpes (Linnaeus, 1758) in the Holarctic was conducted on a sample of 3806 skulls belonging to 41 fox populations. The Nearctic was represented by 948 specimens (249 females, 359 males, 340 specimens of unknown sex) belonging to 13 populations, whereas the Palearctic was represented by 2858 red foxes (1034 females, 1256 males, 568 specimens of unknown sex) from 32 populations. In the Nearctic, the largest foxes live on Kodiak Island (V. v. harrimani) and the Kenai Peninsula (V. v. kenaiensis), while the smallest ones live in California (V. v. necator) and Georgia (V. v. fulvus). In the Palearctic, the largest foxes come from the Far East (V. v. jakutensis, V. v. beringiana, V. v. tobolica), while the smallest are from the southern borders of the Eurasian range (V. v. pusilla, V. v. barbara, V. v. arabica). In both the Palearctic and Nearctic, tooth size in the fox varies depending on the geo-climatic factors. The fox’s tooth size confirms the general basis of Bergmann’s rule. In the Palearctic, specimens with larger teeth occur in cooler habitats with greater seasonality. These are first and foremost Northern and Far Eastern populations. In the Nearctic, tooth size in red foxes depends on the temperature and humidity of their habitat. Competition within the species and between species has important impact on the variation and dimorphism of tooth size in the red fox. Both in the Nearctic and Palearctic, red foxes from regions of sympatric co-occurrence with other closely relatedVulpes species, are more sexually dimorphic in terms of tooth size than red foxes from allopatric regions. Analysis of morphological distance on the basis of the size of dental characteristics shows, that in the Palearctic, the foxes from India (V. v. pusilla), while in the Nearctic, the population from Kodiak Island (V. v. harrimani) are most distant from the remaining populations. Geographic barriers such as the Bering Strait, Parry Channel, Mackenzie River, Kolyma and Omolon River systems have had a critical impact on red fox evolution. The most likely place for the evolution and diversification of the phyletic lineVulpes vulpes seems to be the Middle East region.     

Evaluation of glycoconjugates on the K562 cell surface by means of lectin binding — comparison with human erythrocytes

The binding of five radiolabelled lectins (Vicia graminea, peanut,Phaseolus vulgaris isolectins E-PHA and L-PHA,Evonymus europaeus) to untreated and desialylated K562 cells and human erythrocytes was compared. The number of glycophorin A receptors recognized on the K562 cells by anti-blood group NV. graminea lectin was comparable to that found on the MN or NN erythrocyte surface. However, K562 cells had a severalfold higher number of oligosaccharide chains (presumablyO-glycosidic) which after desialylation became high-affinity receptors for peanut agglutinin, and of complex typeN-glycosidic chains available for the reaction with E-PHA and also with L-PHA (the latter lectin was not bound to erythrocytes). Moreover, K562 cells not treated with neuraminidase had a significant amount of extremely low affinity receptors for peanut agglutinin, whereas binding of this lectin to untreated erythrocytes was undetectable. On the other hand, the untreated K562 cells did not bind anti-blood group B and HE. europaeus lectin, but a small amount of binding by the desialylated cells was observed. Some other differences observed in the mode of lectin binding to K562 cells and erythrocytes are discussed.     

Curcumin abolishes apoptosis resistance of calcitriol-differentiated HL-60 cells

Exposure of HL-60 cells to 1,25-dihydroxyvitamin D(3) (calcitriol) induces their differentiation into monocytes. This terminal differentiation is associated with acquired resistance to many proapoptotic stimuli. Here we show that differentiated HL-60 cells undergo apoptosis upon curcumin treatment although they retain resistance to apoptosis induced by a topoisomerase poison - etoposide. Curcumin induced changes of nuclear morphology, DNA fragmentation, release of cytochrome c as well as caspase activation in both differentiated and undifferentiated cells. Experiments performed in other laboratories suggested that curcumin initiates apoptosis by DNA damage that results from topoisomerase II poisoning. We measured gammaH2AX expression, a marker of DNA double strand breaks, in both undifferentiated and differentiated HL-60 cells treated with curcumin or etoposide. In etoposide-treated undifferentiated cells early gammaH2AX expression correlated with initiation phase of apoptosis. In contrast, in curcumin-treated cells gammaH2AX expression correlated with apoptotic DNA fragmentation, which is characteristic for the execution phase of apoptosis. Our experiments show that curcumin overcomes the resistance of calcitriol-differentiated HL-60 cells to DNA-damage-induced apoptosis by activating other cell signaling pathways leading to cell death of HL-60.     

Genome size stability in six medicinal plant species propagated <Emphasis Type="Italic">in vitro</Emphasis>

DNA content was estimated by flow cytometry in seedlings and in vitro clones of six species: Oenothera paradoxa, Inula verbascifolia ssp. aschersoniana, Rubus chamaemorus, Solidago virgaurea, S. graminifolia and Pueraria lobata. With the exception of P. lobata, there was no difference in genome sizes between seedlings and in vitro cultured plants from any species, indicative that they maintain their genetic stability during in vitro culture. This confirms the usefulness of tissue culture for production of certified plant material to obtain herbal medicines.     

Comparative analysis of phenolic acids and flavonoids in shoot cultures of Eryngium alpinum L.: an endangered and protected species with medicinal value

Plant Cell, Tissue and Organ Culture (PCTOC) - Phenolic acids and flavonoids, important bioactive compounds of polyphenols, play a significant role in plants; their impact, mainly as antioxidants,...     

Adhesive properties of carcinoembryonic antigen glycoforms expressed in glycosylation-deficient Chinese hamster ovary cell lines

Carcinoembryonic antigen (CEA) is an oncofoetal cell surface glycoprotein that serves as an important tumour marker for colorectal and some other carcinomas. Its immunoglobulin-like structure places CEA within the immunoglobulin superfamily. CEA functions in several biological roles including homotypic and heterotypic (with other CEA family members) cell adhesion. Cell-cell interaction can be modulated by different factors, e.g., post-translational modifications such as glycosylation. The purpose of this study was to examine whether changes in carbohydrate composition of CEA oligosaccharides can influence homotypic (CEA-CEA) interactions. In order to modulate glycosylation of CEA we used two different glycosylation mutants of Chinese hamster ovary (CHO) cells, Lec2 and Lec8. Lec2 cells should produce CEA with nonsialylated N-glycans, while Lec8 cells should yield more truncated sugar structures than Lec2. Parental CHO (Pro5) cells and the glycosylation deficient mutants were stably transfected with CEA cDNA. All three CEA glycoforms, tested in a solid-phase cell adhesion assay, showed an ability to mediate CEA-dependent cell adhesion, and no qualitative differences in the adhesion between the glycoforms were observed. Thus, it may be assumed that carbohydrates do not play a role in homotypic adhesion, and the interactions between CEA molecules depend solely on the polypeptide structure.     

Galactosylation of IgG from rheumatoid arthritis (RA) patients – changes during therapy

It is well documented that serum IgG from rheumatoid arthritis (RA) patients exhibits decreased galactosylation of its conservative N-glycans (Asn-297) in CH2 domains of the heavy chains; it has been shown that this agalactosylation is proportional to disease severity. In the present investigation we analyzed galactosylation of IgG derived from the patients using a modified ELISA-plate test, biosensor BIAcore and total sugar analysis (GC-MS). For ELISA and BIAcore the binding of IgG preparations, purified from the patients’ sera, to two lectins: Ricinus communis (RCA-I) and Griffonia simplicifolia (GSL-II) was applied. Based on ELISA-plate test an agalactosylation factor (AF, a relative ratio of GSL-II/RCA-I binding) was calculated, which was proportional to actual disease severity. Repeated testing of several patients before and after treatment with methotrexate (MTX) alone or in combination with Remicade (a chimeric antibody anti-TNF-α) supplied results indicating an increase of IgG galactosylation during the treatment. This introductory observation suggests that IgG galactosylation may be an additional indicator of the RA patients’ improvement.     

Nuclear DNA content as an indicator of inflorescence colour stability of in vitro propagated solid and chimera mutants of chrysanthemum

In chrysanthemum, breeders seek for desirable characteristics of the inflorescence, which can first be established once the plant is mature. The present study aims to determine whether measurement of DNA content can be useful in the detection of somaclonal variants and/or separation of chimera components in chrysanthemum at the early in vitro multiplication stage. Eleven Chrysanthemum?×?morifolium (Ramat.) Hemsl. cultivars of the Lady group (a mother cultivar and ten of its radiomutants obtained by X-ray- or γ-irradiation; solid and periclinal chimeras) were propagated in vitro. Single-node explants were cultured in Murashige and Skoog (MS) medium, either without plant growth regulators (PGRs) or supplemented with 6-benzyladenine (BA) and indole-3-acetic acid (IAA). The nuclear DNA content was measured by flow cytometry (FCM) in the shoots produced in vitro. After acclimatization and growth of the plants in a glasshouse, inflorescence colour was recorded. The addition of PGRs to the medium almost doubled the mean number of shoots produced in vitro per explant, but caused a change in inflorescence colour of all (‘Lady Apricot’; periclinal chimera) or part of the plants (‘Lady Amber’; solid mutant and ‘Lady Salmon’; periclinal chimera). All radiomutants contained less DNA than the mother cultivar ‘Richmond’. There were significant differences in DNA content between plants of the same cultivar grown in media with or without PGRs for ‘Lady Apricot’ and ‘Lady Salmon’, but no phenotype alternation occurred in chrysanthemums produced in PGR-free medium compared to the original cultivars. Conversely, in medium with PGRs, chimeras produced flowers different from the original colour. In all except one cultivar (‘Lady Amber’; solid mutant) a lack of differences in genome size between plants grown in either medium coincided with a stable inflorescence colour. The occurrence of some plants of ‘Lady Amber’ with different inflorescence colour may be due to small DNA changes, undetectable by FCM. It can be concluded that FCM analysis of DNA content in young plantlets can be indicative of the stability of inflorescence colour in chrysanthemum, especially chimeric cultivars, and for mutant detection.