Identification and partial purification of a novel milk clotting enzyme from Onopordum turcicum

Summary Seeds, flowers and leaves of Onopordum turcicum were found to contain proteolytic enzymes able to coagulate milk. Extraction, concentration and identification of the operational parameters affecting the activity of the enzyme complex were followed by partial purification steps involving gel-filtration and ion-exchange chromatography. Milk clotting activity of the enzyme complex was tested in several steps of its purification and an increase of almost 200 fold was obtained. Molecular weight of the proteolytic enzyme fraction having the maximum activity was determined to be about 19000–24000. Isoelectric point (pI) of the enzyme complex with maximum activity was estimated to be in the range 3.3–3.7.     

Interaction between protein kinase C and regulatory ligand is enhanced by a chelatable pool of cellular zinc

At micromolar concentrations, zinc (Zn) and cadmium, but not other metals, greatly augmented binding of [3H]phorbol dibutyrate ([3H]PDBu) to protein kinase C (PKC) in cell homogenates and intact cells (in the presence of ionophore). Increased binding persisted for several hours. The heavy-metal chelating agent 1,10-phenanthroline completely reversed the increased [3H]PDBu binding in cells pretreated with 65Zn and ionophore and this was associated with a decline of about 20% in cell-associated 65Zn, suggesting that a relatively small pool of intracellular Zn acts on PKC. This may be a membrane-associated pool, since 65Zn readily bound to isolated erythrocyte inside-out membranes. Phenanthroline also partially inhibited binding of [3H]PDBu to PKC in untreated cells and extracts in a Zn-reversible manner. Therefore, cellular Zn appears to regulate the interaction of ligand with PKC. PKC bound to a Zn affinity column and was eluted by metal-chelator, confirming that Zn interacts directly with PKC.     

Morphofunctional indices of the effects of pyracryl on the organs of female genital system in rats

Morphofunctional indices of pyracryl (phosphate poly-2-pyridylethylmethacrilate) effecting reproduction system of Wistar rats have been studied. It has been shown that monthly administration of pyracryl in doses 1 mg/kg and 5 mg/kg lead to infiltration of mast cells and their pronounced degranulation and impairment of blood and lymph microcirculation. As far as gonadotropic effect is concerned, its parametres depend on the administration of pyracryl. Pyracryl in doses of 1 mg/kg stimulates folliculogenesis in ovaries, a dose of 5 mg/kg may cause expressed atresia of growing follicules and changes of oestrous cycle. It is suggested that biologically active substances of mast cells in female reproduction system play an important role in realization of gonadotropic effects of pyracryl.     

Biomedical implications from a morphoelastic continuum model for the simulation of contracture formation in skin grafts that cover excised burns

A continuum hypothesis-based model is developed for the simulation of the (long term) contraction of skin grafts that cover excised burns in order to obtain suggestions regarding the ideal length of splinting therapy and when to start with this therapy such that the therapy is effective optimally. Tissue is modeled as an isotropic, heterogeneous, morphoelastic solid. With respect to the constituents of the tissue, we selected the following constituents as primary model components: fibroblasts, myofibroblasts, collagen molecules, and a generic signaling molecule. Good agreement is demonstrated with respect to the evolution over time of the surface area of unmeshed skin grafts that cover excised burns between outcomes of computer simulations obtained in this study and scar assessment data gathered previously in a clinical study. Based on the simulation results, we suggest that the optimal point in time to start with splinting therapy is directly after placement of the skin graft on its recipient bed. Furthermore, we suggest that it is desirable to continue with splinting therapy until the concentration of the signaling molecules in the grafted area has become negligible such that the formation of contractures can be prevented. We conclude this study with a presentation of some alternative ideas on how to diminish the degree of contracture formation that are not based on a mechanical intervention, and a discussion about how the presented model can be adjusted.     

The Effects of Severe Hypobaric Hypoxia and Inhibition of Hypoxia-Inducible Factor-1 (HIF-1) on Biomarkers of Cardiac and Skeletal Muscle Injury in Rats

Biophysics - Abstract—The goal of the present study was to investigate the molecular mechanisms that underlie heart and skeletal muscle damage in male Wistar rats weighing 200–250 g in...     

Photogeneration of NADH under coupled action of CdS semiconductor and hydrogenase from Alcaligenes eutrophus without exogenous mediators.

Photoreduction of NAD has been accomplished by a system consisting of the NAD-dependent hydrogenase from Alcaligenes eutrophus immobilized on CdS particles with formate as artificial electron donor. Enzymatically active NADH is formed under illumination of this system by visible light. Accumulation of the coenzyme dimer (NAD)2 was not detected. NAD photoreduction is supposed to proceed via the direct electron transfer from the semiconductor to the enzyme electron transport chain. However, NADH formation as a result of hydrogenase interaction with anion-radicals (CO2.-) formed in the course of formate photooxidation cannot at present be excluded.     

Multivariate analyses of carbohydrate data from lipopolysaccharides of Actinobacillus (Haemophilus) actinomycetemcomitans, Haemophilus aphrophilus, and Haemophilus paraphrophilus

The taxonomic distinction between Actinobacillus (Haemophilus) actinomycetemcomitans and Haemophilus aphrophilus and the taxonomic distinction between H. aphrophilus and Haemophilus paraphrophilus have been questioned. This study was done to determine whether multivariate statistical analyses of carbohydrate data from lipopolysaccharides could be used to distinguish between these closely related species. Lipopolysaccharides were extracted with phenol-water and purified. Carbohydrates were assessed by using gas chromatography and gas chromatography-mass spectrometry after methanolysis and derivatization with trifluoroacetic acid anhydride. The lipopolysaccharides from all of the species contained rhamnose, fucose, galactose, glucose, L-glycero-D-mannoheptose, and glucosamine plus galactosamine, but in varying amounts. A. actinomycetemcomitans and H. paraphrophilus also contained D-glycero-D-mannoheptose, while H. aphrophilus did not. Sample- and variable-oriented principal-component analyses of the carbohydrate data clearly distinguished among A. actinomycetemcomitans, H. aphrophilus, and H. paraphrophilus. Soft independent modelling of class analogy showed that no sample in the A. actinomycetemcomitans class fell within the 95% confidence limits of the H. aphrophilus class. H. paraphrophilus fell outside both classes.