|
| |
|
| |
|
| |
|
| |
|
| |
|
| |
|
| |
|
|
Characterization of 18,7 and 19 kDa groups of secreted proteins in the salivary glands of the castor bean tick \kur{Ixodes ricinus}
SOUČKOVÁ, Nina
The recombinant protein c90 was prepared and polyclonal antibodies against this protein were raised. The dsRNA was made for the experiments with RNA interference. The samples from dissected tissues of dsRNA silenced ticks were tested by RT-PCR and Western blot. Results suggest that protein c90 plays a role in the tick body during the reaction to injury. Finally, another experiment with injection of water, G+ and G- bacteria into the ticks was realized. It was found that the members of the 18,7 kDa protein family can create multimers. The overexpression of silenced genes was observed during RNAi experiments despite of expected inhibition of c90 production. These results together with the bioinformatics analysis could mean that these proteins are important the physiology of tick probably as a reaction to injury. However c90 protein is produced only in the first phase of feeding which could mean that it has some role in the tick-host interaction as well.
|
|
|
Cold hardiness of larvae of the fruit fly, \kur{Drosophila melanogaster} (Diptera: Drosophilidae)
KORBELOVÁ, Jaroslava
We assessed survival of larvae of the fruit fly, Drosophila melanogaster at low temperatures (0°C and 5°C) after rearing them under seven different acclimation regimes. Larvae that have developed in a standard diet at 25°C showed 50% mortality after 12,6 min of the exposure to 0°C (Lt50 = 0.21 h). In contrast, larvae that have developed in a diet enriched with glycerol at 15°C, and were cold acclimated at 5°C during last two days of their development, had Lt50 = 38.6 h. It means that it was possible to increase the Lt50 at 0°C more than 180-fold using simple manipulations with rearing temperatures and diet composition. The physiological differences in duration of larval development, fresh mass, dry mass, hydration and total contents of proteins, lipids and glycogen between the larvae belonging to different acclimation variants are described. The samples for future detailed metabolomic analysis were prepared.
|
|
|
Interactions of Zn2+ ions with proteins and nucleic acids
DVOŘÁKOVÁ, Kateřina
Interaction of Zn2+ ions with proteins and nucleic acids Zinc is an important metal in biological systems. It is a strong Lewis acid, forms a stable Zn2+ ion and can exist in several coordination geometries. Zinc is required for the activity of more than 300 enzymes. In proteins zinc can either participate directly in chemical catalysis or can be important for maintaining protein structure and stability. In this work a dataset of high quality (resolution better than 3 Ǻ) crystal structures deposited in the Protein Data Bank on internet have been examined to identify typical zinc binding sites and to establish their coordination geometries. Totally 135 zinc binding sites found in 74 structures have been analyzed. The most frequent coordinating atoms are sulphur in cystein, NE2 and ND1 nitrogens in histidine followed by oxygen atoms in carboxylates of aspartic and glutamic acids. 67% of zinc binding sites were found to be four-coordinated with tetrahedral coordination geometry. In contrast Mg2+ cations show a clear preference to bind to oxygen atoms and to form octahedral cavities. We have not found any structure with a direct zinc coordination to DNA except the 1ZQT structure which was however excluded due to its low resolution (> 3 {\AA}). Similarly only three zinc binding sites have been found in RNA structures which were however determined in the protein free environment. All other zinc binding sites have been located in proteins even in the presence of the nucleic acids.
|
guest ::
