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In the present preliminary study we report an investigation on taxonomic status of individuals displaying diagnostic traits of intermediate values between the morphologically typical forms of Athous haemorrhoidalis (Fabricius 1801) and A. vittatus (Gmelin 1790) species occurring sympatrically. The presence of the "intermediate form" invoked the hypothesis of interspecific hybridization between A. haemorrhoidalis and A. vittatus species. An alternative explanation is that the "intermediate form" comprises individuals that are morphological variants of either of the species, without interspecific gene flow. We used partial sequences of two mitochondrial genes coding for the cytochrome oxidase subunit I (cox1) and 16S ribosomal RNA (rrnL), respectively. Additionally, we examined the variability of five polymorphic allozyme loci: 6Pgd, Idh, Mdh, Pgm and Gpi. Altogether, 28 A. haemorrhoidalis, 7 A. vittatus and 8 "intermediate form" individuals were included into the study. Phylogenetic analyses produced the trees of a consistent topology with high statistical support regardless of the method used. The specimens signified as the "intermediate form" constituted a monophyletic group with individuals of A. vittatus species. Empirical data confirmed that the reproductive isolation between the species studied is complete. No haplotype was shared between A. haemorrhoidalis and A. vittatus in sympatry. Similar results were obtained using the analysis of allozyme data. Especially at Idh and 6Pgd loci, alleles characteristic for A. vittatus and the "intermediate form" were not found in A. haemorrhoidalis, despite the larger sample examined. This suggests that the "intermediate form" is a phenotypic variant of A. vittatus without the signature of introgression.
Survivin is a member of apoptosis inhibiting proteins family. Apart from its antiapoptotic activity it plays a critical role in regulating the cell cycle and mitosis. It is overexpressed in most human malignancies. While the prognostic significance of survivin expression is widely investigated in human non-Hodgkin's lymphomas, little is known about its expression in canine lymphomas. The aim of the study was to evaluate the expression of survivin in canine lymphomas in relation to proliferation markers (mitotic index and percentage of Ki67-positive cells). Survivin was found in all examined lymphomas belonging to 6 different morphological subtypes with nuclear immunoreactivity. In most of lymphomas (18/25) survivin expression ranged 10%-25% of positive cells. Only single cases had lower (0-10% positive cells, 1/25) or higher (25-50% and >50% positive cells, 5/25 and 1/25, respectively) index of survivin. Neither mitotic index nor proliferative index correlated with survivin expression when the values quantified randomly in whole specimens were compared. However, when survivin expression were quantified in selected tumor areas of low and high proliferation activity the high correlations between survivin expression and proliferation index were found. The results indicated that survivin is commonly expressed in canine lymphomas. Nuclear labelling together with the relation of its expression and proliferative activity in highly proliferative areas of neoplastic tissue suggest a potential role of survivin in cell cycle activation in canine lymphoma cells. However, further studies of the relation between expression of survivin and other proteins involved in cell cycle regulation are needed. Moreover, the results suggest that survivin may pose the therapeutic target in canine lymphomas.
Plants growing under natural conditions are constantly exposed to ultraviolet (UV), primarily UV-A, radiation. Grass pea (Lathyrus sativus L.) is a legume species resistant to harsh growing conditions, such as drought, salinity or periodic flooding. Due to the advantageous composition of seeds, it is used for consumption in such regions as South Asia or East Africa where high intensity of UV radiation occurs. Absorption of this spectral range causes changes in the photosynthetic apparatus of plants, including damage to the photosystem II (PSII) reaction centres. The aim of the work was to examine whether the use of the combination UV-A: red light as a source of radiation would enable quick acclimatization of the photosynthetic apparatus of grass pea to the negative effect of UV-A radiation. 14-day-old plants were exposed to UV-A:red radiation for 48 h. The plants exposed to UV-A:red radiation showed enhanced effective efficiency of PSII and increased total electron carriers, which enabled more effective photosynthesis at higher values of radiation intensity in comparison with control plants, kept under white LED light. At the same time, there were no statistically significant differences in both the photosynthetic pigment contents and the level of lipid peroxidation. The obtained results indicate that the observed increase in the efficiency of CO₂ carboxylation after short-term UV-A:red radiation has resulted from the efficient linear electron transport due to maintaining the effective oxygen evolving complex (OEC) and increased total electron carriers.
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