Materials and methods:The present study is the first to apply DNA barcoding on identifying 37 freshwater fish species from the rich Balkan ichthyofauna. Results: The results are highly successful since in most cases barcodes cluster according to species, in agreement with morphological taxonomic studies. This is also evident based on mean conspecific and congeneric Kimura two-parameter distance values. The 5.6-fold difference between these values is lower than previous barcoding studies, possibly due to the restricted samplings and the recent taxonomy reevaluation for several species. A number of species were identified, where future work is needed: For the species Scardinius erythrophthalmus, Perca fluviatilis, and Rutilus rutilus, the divergence values found among conspecific populations could warrant their placement into different species; for Barbus and Rhodeus populations, the reported interspecific distances found were lower than expected; and for Cobitis species, the application of barcoding seems problematic, due to their complicated reproduction. Conclusion: The extension of this work to other Greek or even Balkan freshwater systems should clarify the situation.
We conclude that exercise induces changes in cytokine levels, thereby possibly affecting epigenetic patterns and activity of tumor-competitive lymphocytes.
Exercise has been proven to reduce the risk and progression of various diseases, such as cancer, diabetes and neurodegenerative disorders. Increasing evidence suggests that exercise affects the cytokine profile and changes distribution and function of tumor-competitive immune cells. Initial studies have shown that different exercise interventions are associated with epigenetic modifications in different tissues and cell types, such as muscle, fat, brain and blood. The present investigation examines the effect of an intense endurance run (half marathon) on global epigenetic modifications in natural killer (NK) cells in 14 cancer patients compared to 14 healthy controls. We were able to show that histone acetylation and NKG2D expression, a functional NK cell marker, were elevated for at least 24 h after the run. Thus, this is the first study to present a potential mechanism of how exercise may impact NK cell activity on the subcellular level. Further studies should focus on epigenetic mechanisms and dose-dependent effects of exercise.
Positive effects of exercise on cancer prevention and progression have been proposed to be mediated by stimulating natural killer (NK) cells. Because NK cell receptors are regulated by epigenetic modifications, we investigated whether acute aerobic exercise and training change promoter DNA methylation and gene expression of the activating KIR2DS4 and the inhibiting KIR3DL1 gene. Sixteen healthy women (50–60 years) performed a graded exercise test (GXT) and were randomized into either a passive control group or an intervention group performing a four-week endurance exercise intervention. Blood samples (pre-, post-GXT and post-training) were used for isolation of DNA/RNA of NK cells to assess DNA promoter methylation by targeted deep-amplicon sequencing and gene expression by qRT-PCR. Potential changes in NK cell subsets were determined by flow cytometry. Acute and chronic exercise did not provoke significant alterations of NK cell proportions. Promoter methylation decreased and gene expression increased for KIR2DS4 after acute exercise. A high gene expression correlated with a low methylation of CpGs that were altered by acute exercise. Chronic exercise resulted in a minor decrease of DNA methylation and did not alter gene expression. Acute exercise provokes epigenetic modifications, affecting the balance between the activating KIR2DS4 and the inhibiting KIR3DL1, with potential benefits on NK cell function.
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