Genotype-specific interactions and the trade-off between host and parasite fitness

Background  

Evolution of parasite traits is inextricably linked to their hosts. For instance one common definition of parasite virulence is the reduction in host fitness due to infection. Thus, traits of infection must be viewed in both protagonists and may be under shared genetic and physiological control. We investigated these questions on the oomycete Hyaloperonospora arabidopsis (= parasitica), a natural pathogen of the Brassicaceae Arabidopsis thaliana.     

Putative candidate genes for blood pressure control in the SHR.BN-RNO8 congenic substrains

The SHR-Lx congenic strain carrying a differential segment of chromosome 8 of BN and PD origin was recently shown to exhibit a significant decrease in blood pressure as compared to the SHR strain. There were two positional candidate genes for blood pressure control mapped to the differential segment: the rat kidney epithelial potassium channel gene (Kcnj1) and brain dopamine receptor 2 gene (Drd2). Bot these genes were separated into SHR.BN-RNO8 congenic substrains. In this communication, we are presenting the assignment of two further putative candidate genes, which might be involved in blood pressure control to the BN/PD differential segment of the SHR-Lx congenic strain. These are: the gene coding for smooth muscle cell specific protein 22 (Sm22) defined by the D8Mcw1 marker and neuronal nicotinic acetylcholine receptor gene cluster, defined by the D8Bord1 marker. Moreover, the glutamate receptor gene Grik4 which also maps to the differential segment of the SHR-Lx should be taken into account. The genetic separation of all these putative candidate genes of blood pressure control is being performed by recombinations and subsequent selection using (SHR×SHR-Lx) intercross population.     

Magnesium potentiation of iron-transferrin binding

The binding of iron to transferrin was studied by loading iron (III) onto apotransferrin in a chloride and a nitrilotriacetate form. When magnesium was added, a marked increase occurred in both the rate of iron binding and the maximum level of iron loaded on transferrin utilizing either iron salt. In the absence of magnesium the amount of iron required to achieve 50 percent saturation of the binding sites was 1.6 x 10(-4) M, whereas when magnesium was added, only about one-third as much iron (0.54 x 10(-4) M) was required. These data suggest an allosteric effect on transferrin by magnesium which potentiates iron (III) binding.     

Bifidobacteria-mediated immune system imprinting early in life

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Towards resolving conservation issues through historical aerial imagery: vegetation cover changes in the Central European tundra

Mountain ecosystems are considered to be sensitive to global change and human disturbance. Our retrospective analysis of archival aerial imagery showed dynamics of arctic-alpine tundra vegetation in the Krkono?e Mountains, Czech Republic; image classification revealed a change in land cover classes in 44% of the study area over the past eighty years. This particular ecosystem holds many rare features, such as high numbers of endemic, glacial relict and rare species as well as relict geomorphological components such as sorted patterned ground. Our study revealed an accelerating expansion of the native and planted shrub, Pinus mugo, from 30.6% of the study area in 1936 to 48.6% in 2018, mostly at the expense of grasslands that decreased from 59.3% in 1936 to 44.2% in 2018. Shrub expansion represents a threat to relict periglacial landforms, covering 8% of the sorted patterned ground in 1936 and 26.5% in 2018. Shrub encroachment was shown to be due to artificial planting of the pine in the past as well as the cessation of former farming (mowing and cattle grazing) and, most probably, also by global change. Both dwarf pine stands and tundra grasslands hold high conservation value (Natura 2000 habitats); a balance between different nature protection interests must, therefore, be ensured. Detailed spatio-temporally, explicit outputs of the remote sensing analysis can serve as a baseline for nature conservation in order to prepare corresponding management plans.