Redox-responsive and calcium-dependent switching of glycosyldisulfide interactions with Concanavalin A

Glycosyldisulfides can interact efficiently with carbohydrate-binding entities. This has been shown for a range of thiosaccharide dimers when tested for their effects against the lectin Concanavalin A using a modified quartz crystal microbalance-technique. Contrary to the thiosaccharide monomers, showing no significant binding up to 10 mM, several of the dimers showed IC(50)-values in the low millimolar range. Three of the glycosyldisulfides tested also displayed very high positive apparent cooperativity effects that were found to be both calcium-dependent and redox-responsive.     

Handling three regulatory elements in one transgene: combined use of cre-lox, FLP-FRT, and I-Scel recombination systems

Studies of regulatory systems in transgenic Drosophila are often compromised by possible genomic position effects on gene expression. As a result, it is desirable to be able to manipulate multiple regulatory elements in a single transgene construct. We developed an I-SceI endonuclease-based method to efficiently delete preassigned sequences from transgenes with the use of direct repeat sequences of just 126 nucleotides. This system can be used in combination with the existing cre-lox and FLP-FRT recombinational mechanisms in order to modify up to three regulatory regions in a given transgene. We validated the utility of our combination approach by demonstrating new properties of the Fab-7 insulator.     

Urine surface tension in patients with urolithiasis treated with pharmalite

It was shown that pharmalite is an effective drug in the therapy of urolithiasis. The efficiency of pharmalite was determined from the surface tension of urine.     

P element-mediated duplications of genomic regions in Drosophila melanogaster

Previously we have described highly unstable yellow mutations induced by chimeric elements that consist of genomic sequences originating from different regions of the X chromosome flanked by identical copies of an internally deleted 1.2 kb P element. To study further the origin and the mechanism of formation of chimeric mobile elements, we analyzed complex y-sc mutations, induced by inversions between P elements located in the neighboring yellow and scute loci. The breakpoints of the inversions are flanked by two P elements in head-to-head orientation on one side and by one P element on the other side. Such an arrangement of P elements leads to frequent duplication into the site between the two P element copies located in head-to-head orientation of the yellow sequences adjacent to the single P element. The duplicated yellow sequences either partly replace the sequence of one of the P elements or are inserted between the conserved head-to-head oriented P elements. In some cases two copies of the yellow sequence are duplicated between the P elements in inverted tail-to-tail orientation. The structure of the P elements at the place of duplication and of the P element- yellow junction suggests that the described duplications, which form chimeric mobile elements, are generated through the previously proposed synthesis-dependent strand annealing mechanism.     

Potentials of enzyme tests and radioisotope hepatography in detecting early functional changes in the liver

The enzymic tests and radionuclide hepatography were used to study and compare liver function after rabbits were exposed to tetrachloromethane poisoning. The activity of serum enzymes of cholinesterase, alkaline phosphatase, aldolase and leucine aminopeptidase was determined. Hepatography was made with the use of 198Au-colloid with an activity 0.74 MBC. The enzymic tests were demonstrated to be more sensitive than radionuclide hepatography in detecting the earliest parenchymatous lesions in the liver. The data obtained correlate with the data of the pathohistological examinations, which demonstrated the presence of marked vacuole parenchymatous fatty dystrophy. The authors recommend that the enzymic tests should be used for detecting early hepatic lesions induced by tetrachloromethane.     

Motivational Modulation of Self-Initiated and Externally Triggered Movement Speed Induced by Threat of Shock: Experimental Evidence for Paradoxical Kinesis in Parkinson’s Disease

Background

Paradoxical kinesis has been observed in bradykinetic people with Parkinson’s disease. Paradoxical kinesis occurs in situations where an individual is strongly motivated or influenced by relevant external cues. Our aim was to induce paradoxical kinesis in the laboratory. We tested whether the motivation of avoiding a mild electric shock was sufficient to induce paradoxical kinesis in externally-triggered and self-initiated conditions in people with Parkinson’s disease tested on medication and in age-matched controls.

Methods

Participants completed a shock avoidance behavioural paradigm in which half of the trials could result in a mild electric shock if the participant did not move fast enough. Half of the trials of each type were self-initiated and half were externally-triggered. The criterion for avoiding shock was a maximum movement time, adjusted according to each participant’s performance on previous trials using a staircase tracking procedure.

Results

On trials with threat of shock, both patients with Parkinson’s disease and controls had faster movement times compared to no potential shock trials, in both self-initiated and externally-triggered conditions. The magnitude of improvement of movement time from no potential shock to potential shock trials was positively correlated with anxiety ratings.

Conclusions

When motivated to avoid mild electric shock, patients with Parkinson’s disease, similar to healthy controls, showed significant speeding of movement execution. This was observed in both self-initiated and externally-triggered versions of the task. Nevertheless, in the ET condition the improvement of reaction times induced by motivation to avoid shocks was greater for the PD patients than controls, highlighting the value of external cues for movement initiation in PD patients. The magnitude of improvement from the no potential shock to the potential shock trials was associated with the threat-induced anxiety. This demonstration of paradoxical kinesis in the laboratory under both self-initiated and externally-triggered conditions has implications for motivational and attentional enhancement of movement speed in Parkinson’s disease.     

Blister‐inducing antibodies target multiple epitopes on collagen VII in mice

Epidermolysis bullosa acquisita (EBA) is an autoimmune subepidermal blistering disease of mucous membranes and the skin caused by autoantibodies against collagen VII. In silico and wet laboratory epitope mapping studies revealed numerous distinct epitopes recognized by EBA patients' autoantibodies within the non‐collagenous (NC)1 and NC2 domains of collagen VII. However, the distribution of pathogenic epitopes on collagen VII has not yet been described. In this study, we therefore performed an in vivo functional epitope mapping of pathogenic autoantibodies in experimental EBA. Animals (n = 10/group) immunized against fragments of the NC1 and NC2 domains of collagen VII or injected with antibodies generated against the same fragments developed to different extent experimental EBA. Our results demonstrate that antibodies targeting multiple, distinct epitopes distributed over the entire NC1, but not NC2 domain of collagen VII induce blistering skin disease in vivo. Our present findings have crucial implications for the development of antigen‐specific B‐ and T cell‐targeted therapies in EBA.