Pedagogická diagnostika a pedagogické diagnostikování

Title in English: Educational assessment and diagnostic assessment: Textbook The textbook introduces students to diagnostic assessment and the theory of educational assessment. Students get acquainted with the basic methods and tools of educational assessment, learn about the process of diagnostic activities and the importance of cooperation with experts during diagnostic activities in practice. The study text is supplemented by practical examples and links to further resources that can help students understand teachers' diagnostic work

Heterologous expression, purification and characterization of nitrilase from Aspergillus niger K10

<p>Abstract</p> <p>Background</p> <p>Nitrilases attract increasing attention due to their utility in the mild hydrolysis of nitriles. According to activity and gene screening, filamentous fungi are a rich source of nitrilases distinct in evolution from their widely examined bacterial counterparts. However, fungal nitrilases have been less explored than the bacterial ones. Nitrilases are typically heterogeneous in their quaternary structures, forming short spirals and extended filaments, these features making their structural studies difficult.</p> <p>Results</p> <p>A nitrilase gene was amplified by PCR from the cDNA library of <it>Aspergillus niger </it>K10. The PCR product was ligated into expression vectors pET-30(+) and pRSET B to construct plasmids pOK101 and pOK102, respectively. The recombinant nitrilase (Nit-ANigRec) expressed in <it>Escherichia coli </it>BL21-Gold(DE3)(pOK101/pTf16) was purified with an about 2-fold increase in specific activity and 35% yield. The apparent subunit size was 42.7 kDa, which is approx. 4 kDa higher than that of the enzyme isolated from the native organism (Nit-ANigWT), indicating post-translational cleavage in the enzyme's native environment. Mass spectrometry analysis showed that a C-terminal peptide (Val₃₂₇- Asn₃₅₆) was present in Nit-ANigRec but missing in Nit-ANigWT and Asp₂₉₈-Val₃₁₃peptide was shortened to Asp₂₉₈-Arg₃₁₀in Nit-ANigWT. The latter enzyme was thus truncated by 46 amino acids. Enzymes Nit-ANigRec and Nit-ANigWT differed in substrate specificity, acid/amide ratio, reaction optima and stability. Refolded recombinant enzyme stored for one month at 4°C was fractionated by gel filtration, and fractions were examined by electron microscopy. The late fractions were further analyzed by analytical centrifugation and dynamic light scattering, and shown to consist of a rather homogeneous protein species composed of 12-16 subunits. This hypothesis was consistent with electron microscopy and our modelling of the multimeric nitrilase, which supports an arrangement of dimers into helical segments as a plausible structural solution.</p> <p>Conclusions</p> <p>The nitrilase from <it>Aspergillus niger </it>K10 is highly homologous (≥86%) with proteins deduced from gene sequencing in <it>Aspergillus </it>and <it>Penicillium </it>genera. As the first of these proteins, it was shown to exhibit nitrilase activity towards organic nitriles. The comparison of the Nit-ANigRec and Nit-ANigWT suggested that the catalytic properties of nitrilases may be changed due to missing posttranslational cleavage of the former enzyme. Nit-ANigRec exhibits a lower tendency to form filaments and, moreover, the sample homogeneity can be further improved by <it>in vitro </it>protein refolding. The homogeneous protein species consisting of short spirals is expected to be more suitable for structural studies.</p

Aktivní politika zaměstnanosti se zaměřením na společensky účelná pracovní místa v okrese Opava

Import 19/04/2006Prezenční výpůjčkaVŠB - Technická univerzita Ostrava. Ekonomická fakulta. Katedra (153) veřejné ekonomik

The relationship between morphology and disaccharidase activity in ischemia- reperfusion injured intestine

Background: Questions regarding functional markers characterizing injured intestines remain unanswered. Brush border disaccharidases are crucial for the functioning of the intestines. Aims: The study was designed to assess changes in disaccharidase activity (DA) following intestinal injury and to compare them with morphological changes. Methods: Wistar rats, randomly divided into six experimental groups (each n = 6), were subjected to different ischemic/reperfusion injury. One-hour mesenteric ischemia followed by reperfusion for 0, 1, 2, 4, 12 or 24 hours was induced. As a control group sham-operated animals were used (n = 6). Intestine morphology was evaluated using histopathological injury index (HII) and goblet cell (GC) detection. DA (sucrase and maltase) was studied in mucosal scrape or in entire intestinal wall samples. Results: Moderate morphological damage (HII, GC) after mesenteric ischemia was detected. Deepening of the injury was found during reperfusion with a maximum after two hours. Improved morphology with longer reperfusion confirmed reversible damage with almost normal mucosal structure after 24 hours of reperfusion. Similar pattern was observed when DA was measured. The lowest activity was detected after 2 hours of reperfusion followed by increasing activity in the subsequent reperfusion periods. Physiological values after 24 hours of reperfusion were seen only in samples of entire intestinal wall. Conclusions: Significant changes in intestinal DA were observed after intestinal ischemia/reperfusion injury. A similar pattern was seen for morphological characteristics. Although based on microscopic survey the intestine seems to be fairly regenerated, some functional limitation is expected to persist

Trehalase as a possible marker of intestinal ischemia -- reperfusion injury

Background: Different pathological affections of the small intestine cause corresponding morphological and functional changes. The present study was aimed to assess intestinal trehalase activities during ischemia and following reperfusion, correlate them with the pathological changes and determine whether trehalase could be used as a biochemical marker of the intestinal ischemia, ischemia — reperfusion injury. Material and methods: Wistar rats, randomly divided into 5 experimental groups (IR) (each n=15), were subjected to one hour mesenteric ischemia followed by 0, 1, 4, 12 and 24 hours of reperfusion. As a control group sham operated animals were used (n=15). The activity of trehalase was determined using an adapted Dahlqwist method. The range of intestinal injury was determined using histologica

Morphological and apoptotic changes in the intestinal mucosa and lung parenchyma after ischaemic/reperfusion injury of the jejunum

Ischaemic/reperfusion (IR) injury of the small intestine may lead to the development of multiple organ failure. Little is known about the morphological changes occurring in the organs during the subacute course of this syndrome. The objective of this study was to observe histopathological features and the role of apoptosis in the jejunal mucosa and lung parenchyma after intestinal IR injury in a long-term experiment. Wistar rats (n = 36) were divided into 4 experimental groups (IR10, IR20, IR30, S). Groups IR10, IR20 and IR30 (each n = 10) were subjected to 1-hour ischaemia of the cranial mesenteric artery followed by 10, 20 or 30 days of reperfusion, respectively. The control group S (n = 6) was not subjected to ischaemia. The jejunal mucosa remained intact after all periods of reperfusion. Apoptotic cells were found particularly in the lamina propria, with the most significant difference observed in the IR30 group (P < 0.01). The lung parenchyma had lower regenerative capacity, which was confirmed by a high index of histological damage after 30 days of reperfusion (P < 0.01) and by the presence of an increased number of apoptotic cells, especially in the pulmonary interstitium. The number of apoptotic cells was ten times higher than in the control group (P < 0.001)

Metabolites of Tryptophane and Phenylalanine as Markers of Small Bowel Ischemia-Reperfusion Injury

Ischemic-reperfusion injury of the small intestine is an acute clinical condition with high mortality rate. This study describes the changes in levels of phenylalanine and tryptophan metabolites in intestinal homogenates and urine samples of Wistar male rats after 60 minutes of mesenteric ischemia and different reperfusion periods (1, 24, 30 hours) in comparison with a control group without the ischemia. The ischemic-reperfusion injury was quantified by the histopathological injury index. The levels of serotonin, epinephrine, and norepinephrine were determined in the intestinal homogenate and epinephrine, vanillylmandelic acid, and the 5-hydroxyindoleacetic acid was analyzed in urine using the HPLC method. The statistically significant increased level of serotonin, epinephrine and norepinephrine were detected in the intestinal samples after 24 hours of reperfusion (p<0.01); even the most elevated serotonin level was observed after one hour of reperfusion (p<0.001). A statistically significant decreased level of vanillylmandelic acid was observed after one hour of reperfusion, but it significantly increased after 24 hours (p<0.05) in urine. The elevated level of the 5-hydroxyindoleacetic acid after one hour and 24 hours after reperfusion (p<0.05) were determined in the urine. The most significant elevated epinephrine level was observed after 24 hours of reperfusion (p<0.001) in urine. Results showed a potential role of serotonin as an early biomarker (after one hour of reperfusion) of small intestinal damaged homogenate, while the best predictor of intestinal injury in urine was epinephrine, which was elevated after 24 hours