Statistical testing of directions observations independence

Independence of observations is often assumed when adjusting geodetic network. Unlike the\ud distance observations, no dependence of environmental conditions is known for horizontal\ud direction observations. In order to determine the dependence of horizontal direction observations,\ud we established test geodetic network of a station and four observation points. Measurements of\ud the highest possible accuracy were carried out using Leica TS30 total station along with precise\ud prisms GPH1P. Two series of hundred sets of angles were measured, with the first one in bad\ud observation conditions. Using different methods, i.e. variance–covariance matrices, x2 test and analyses of time series, the independence of measured directions, reduced directions and horizontal angles were tested. The results show that the independence of horizontal direction\ud observations is not obvious and certainly not in poor conditions. In this case, it would be appropriate for geodetic network adjustments to use variance–covariance matrix calculated from measurements instead of diagonal variance–covariance matrix

Phylogenomic analysis of the cystatin superfamily in eukaryotes and prokaryotes

<p>Abstract</p> <p>Background</p> <p>The cystatin superfamily comprises cysteine protease inhibitors that play key regulatory roles in protein degradation processes. Although they have been the subject of many studies, little is known about their genesis, evolution and functional diversification. Our aim has been to obtain a comprehensive insight into their origin, distribution, diversity, evolution and classification in Eukaryota, Bacteria and Archaea.</p> <p>Results</p> <p>We have identified <it>in silico </it>the full complement of the cystatin superfamily in more than 2100 prokaryotic and eukaryotic genomes. The analysis of numerous eukaryotic genomes has provided strong evidence for the emergence of this superfamily in the ancestor of eukaryotes. The progenitor of this superfamily was most probably intracellular and lacked a signal peptide and disulfide bridges, much like the extant Giardia cystatin. A primordial gene duplication produced two ancestral eukaryotic lineages, cystatins and stefins. While stefins remain encoded by a single or a small number of genes throughout the eukaryotes, the cystatins have undergone a more complex and dynamic evolution through numerous gene and domain duplications. In the cystatin superfamily we discovered twenty vertebrate-specific and three angiosperm-specific orthologous families, indicating that functional diversification has occurred only in multicellular eukaryotes. In vertebrate orthologous families, the prevailing trends were loss of the ancestral inhibitory activity and acquisition of novel functions in innate immunity. Bacterial cystatins and stefins may be emergency inhibitors that enable survival of bacteria in the host, defending them from the host's proteolytic activity.</p> <p>Conclusion</p> <p>This study challenges the current view on the classification, origin and evolution of the cystatin superfamily and provides valuable insights into their functional diversification. The findings of this comprehensive study provide guides for future structural and evolutionary studies of the cystatin superfamily as well as of other protease inhibitors and proteases.</p

Mouse stefins A1 and A2 (Stfa1 and Stfa2) differentiate between papain-like endo- and exopeptidases

AbstractStefin A (Stfa) acts as a competitive inhibitor of intracellular papain-like cysteine proteases which play important roles in normal cellular functions such as general protein turnover, antigen processing and ovarian follicular growth and maturation. In the mouse there are at least three different variants of Stfa (Stfa1, Stfa2 and Stfa3). Recent genetic studies identified structural polymorphisms in Stfa1 and Stfa2 as candidates for Aod1b, a locus controlling susceptibility to day three thymectomy (D3Tx)-induced autoimmune ovarian disease (AOD). To evaluate the functional significance of these polymorphisms, recombinant allelic proteins were expressed in Escherichia coli, purified and characterized. The polymorphisms do not markedly alter the folding characteristics of the two proteins. Stfa1 and Stfa2 both act as fast and tight binding inhibitors of endopeptidases papain and cathepsins L and S, however their interaction with exopeptidases cathepsins B, C and H was several orders of magnitude weaker compared to human, porcine and bovine Stfa. Notwithstanding, the Ki values for the interactions of Stfa1-b from AOD resistant C57BL/6J mice was 10-fold higher than that of the Stfa1-a allele from susceptible A/J mice for papain, cathepsins B, C and H but not L and S. In contrast, the inhibitory activities of Stfa2-a and Stfa2-b were found to be roughly equivalent for all targets peptidases

Crystal structures of human procathepsin B at 3.2 and 3.3 Å resolution reveal an interaction motif between a papain-like cysteine protease and its propeptide

AbstractA wild-type human procathepsin B was expressed, crystallized in two crystal forms and its crystal structure determined at 3.2 and 3.3 Å resolution. The structure reveals that the propeptide folds on the cathepsin B surface, shielding the enzyme active site from exposure to solvent. The structure of the enzymatically active domains is virtually identical to that of the native enzyme [Musil et al. (1991) EMBO J. 10, 2321–2330]: the main difference is that the occluding loop residues are lifted above the body of the mature enzyme, supporting the propeptide structure

Crystal Structure of the Soluble Form of Equinatoxin II, a Pore-Forming Toxin from the Sea Anemone Actinia equina

AbstractBackground: Membrane pore–forming toxins have a remarkable property: they adopt a stable soluble form structure, which, when in contact with a membrane, undergoes a series of transformations, leading to an active, membrane-bound form. In contrast to bacterial toxins, no structure of a pore-forming toxin from an eukaryotic organism has been determined so far, an indication that structural studies of equinatoxin II (EqtII) may unravel a novel mechanism.Results: The crystal structure of the soluble form of EqtII from the sea anemone Actinia equina has been determined at 1.9 Å resolution. EqtII is shown to be a single-domain protein based on a 12 strand β sandwich fold with a hydrophobic core and a pair of α helices, each of which is associated with the face of a β sheet.Conclusions: The structure of the 30 N-terminal residues is the largest segment that can adopt a different structure without disrupting the fold of the β sandwich core. This segment includes a three-turn α helix that lies on the surface of a β sheet and ends in a stretch of three positively charged residues, Lys-30, Arg-31, and Lys-32. On the basis of gathered data, it is suggested that this segment forms the membrane pore, whereas the β sandwich structure remains unaltered and attaches to a membrane as do other structurally related extrinsic membrane proteins or their domains. The use of a structural data site-directed mutagenesis study should reveal the residues involved in membrane pore formation

The Impact of Anthropometric Parameters on the Incidence of Low Back Pain

Endogenic factors as one of possible reasons for low back pain were investigated and discussed in this study. The study included 122 male bus drivers, average age 44.2 years, average period of active service 24.4 years. The following anthropometric indexes have been calculated: Quetelet’s index, percentage of body fat, relative body weight, Olivier’s typologic index, Lorenz’s constitution index and muscle index. According to inquiry form regarding history of low back pain the subjects were divided in two groups: 36 had no low back pain history and 76 had a history of recurrent low back pain. The results showed statistically nonsignificant differences in the anthropometric parameters and the calculated indexes between these two groups of subjects. The chosen subject sample showed that nutritional status, body build, constitution and muscular development are not associated with the incidence of low back pain

Non-invasive in vivo imaging of tumour-associated cathepsin B by a highly selective inhibitory DARPin

Cysteine cathepsins often contribute to cancer progression due to their overexpression in the tumour microenvironment and therefore present attractive targets for non-invasive diagnostic imaging. However, the development of highly selective and versatile small molecule probes for cathepsins has been challenging. Here, we targeted tumour-associated cathepsin B using designed ankyrin repeat proteins (DARPins). The selective DARPin 8h6 inhibited cathepsin B with picomolar affinity (Ki = 35 pM) by binding to a site with low structural conservation in cathepsins, as revealed by the X-ray structure of the complex. DARPin 8h6 blocked cathepsin B activity in tumours ex vivo and was successfully applied in in vivo optical imaging in two mouse breast cancer models, in which cathepsin B was bound to the cell membrane or secreted to the extracellular milieu by tumour and stromal cells. Our approach validates cathepsin B as a promising diagnostic and theranostic target in cancer and other inflammation-associated diseases

Measurement of Spinal Sagittal Curvatures using the Laser Triangulation Method

The purpose of the first part of the study was to establish the variability of repeated measurements in different measuring conditions. In the second part, we performed in a large number of patients, a measurement of thoracic kyphosis and lumbar lordosis and compared them to age, gender, and level of nourishment. In the first part, measurements were performed on a plastic model of the back of a patient with a rigid and a normal spine. In the second part, 250 patients participated in the study (126 men and 124 women). For measuring spinal curvatures we used an apparatus for laser triangulation constructed at the Faculty of Mechanical Engineering, University of Ljubljana. A comparison of 30 repeated measurements was shown as the average value±2 SD which included 95% of the results. Thirty repeated readings of one 3D measurement: thoracic kyphosis 41.2°±0.6°, lumbar lordosis 4.4°±1.2°; 30 measurements on a plastic model: thoracic kyphosis 36.8°±1.2°, lumbar lordosis 30.9°±2.0°; 30 measurements on a patient with a rigid spine: thoracic kyphosis 41.5°±2.4°, lumbar lordosis 4.0°±1.8°; 30 measurements on a patient with a normal spine: thoracic kyphosis 48.8°±7.4°, lumbar lordosis 21.1°±4.4°. The average size of thoracic kyphosis in 250 patients was 46.8° (SD 10.1°) and lumbar lordosis 31.7° (SD 12.5°). The angle size was statistically significantly correlated to gender (increased thoracic kyphosis and lumbar lordosis in women) and body mass index (increased thoracic kyphosis and lumbar lordosis in more nourished patients). Age was not significantly correlated to the observed angles. During measurements of the spinal angles it was important to pay attention to relaxation and the patient’s position as well as to perform more measurements providing the average value. The age and the level of nourishment influence the size of the sagittal spinal angles. In the observed sample the effect of age was not confirmed