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The aim of the present study was to determine whether orally applied collagen fragments (CFs) could affect the development of obesity in obese rats. To this end, experimental rats that were exposed to a high-calorie diet (HCD) for four weeks were randomly divided into two groups: HCD and HCD+CFs, with both groups continuing to receive the HCD. However, rats from the HCD+CFs group were also provided with CFs in a 0.05-M citrate buffer (pH 5.0) (1 g•kg-1 of body weight) by intragastric administration, every other day for the next six weeks. Selected parameters associated with obesity development and insulin resistance, as well as serum markers of oxidative stress and the cytokine profile were assessed at the end of the 10 th week. Supplementation with CFs resulted in a decrease in body weight and body mass index when compared to animals exposed to a HCD. The observed changes were assumed to be caused by a lower food intake and increased water intake by obese rats treated with CFs. Enhanced activity of superoxide dismutase (SOD), catalase (CAT) and decreased malondialdehyde (MDA) concentration were detected in the HCD+CF group of animals when compared to untreated HCD-fed rats. Administration of CFs also lowered the serum concentrations of the proinflammatory cytokines IL-1β and IL-12, whereas the concentration of the anti-inflammatory cytokine IL-10 was significantly increased and the concentration of cytokine IL-4 was near the control value. Decreased concentrations of fasting blood glucose, glycated hemoglobin (GHbA1c) and serum insulin and increased tolerance to glucose in the oral glucose tolerance test (OGTT) were observed in the HCD+CF group of animals when compared to rats in the HCD group. We concluded that CFs mediated a therapeutic effect on obesity development in rats exposed to a HCD by affecting pathways involved in obesity pathogenesis.

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The aim of the present study was to evaluate the hypoglycemic activity of the aqueous extract from the fruit walls of Phaseolus vulgaris pods and to examine the potential mechanism underlying the improvement of the glycemic level. In the course of the study, diabetes mellitus was induced in rats with a single intraperitoneal injection of streptozotocin (45 mg·kg−1 b.w.). Diabetic and control rats were then orally administered with a single-dose or repeated-dose (28 day) of P. vulgaris extract (200 mg·kg−1). Results show that the extract was found to possess significant hypoglycemic activity, and the study of glucose utilization by isolated rat hemidiaphragm suggests that the aqueous extract may enhance the peripheral utilization of glucose. The subsequent experiments have revealed that the P. vulgaris extract could increase glucose transporter 4 (GLUT-4) content in skeletal muscle cells of control and diabetic rats. Our data also indicate that the P. vulgaris extract did not affect the content of the insulin receptor, but significantly reduced the total tyrosine kinase activity in skeletal muscle cells of both experimental groups of rats. The present results clearly indicated that P. vulgaris extract may be beneficial for reducing hyperglycemia through its potency in regulation of glucose utilization via GLUT-4, but the current mechanism remains to be unidentified.

The accumulated data indicate that a high level of homocysteine may be a central pathogenetic factor of chronic obstructive pulmonary disease. In this study, we investigated the effect of hyperhomocysteinemia on protein homeostasis in the rat lungs. The level of proteins, peptides, total proteolytic activity, as well as protein-peptide composition, were evaluated. Hyperhomocysteinemia was induced by daily intragastric administration of DL-homocysteine thiolactone (100 mg·kg-1 of body weight) to albino non-linear male rats for 28 days. Twelve hours after the last administration, the rats were sacrificed and the lungs were harvested. Our findings showed that hyperhomocysteinemia caused the disturbances in the protein homeostasis in the lungs that are manifested by a decrease in the level of proteins in the young and old animals and an increase in the level of peptides in the rats of all studied groups. We found a change in the protein composition in the lung of HM rats - a decrease in the level of proteins with a molecular weight of 50 kDa to 100 kDa simultaneously with an increase in the level of proteins with a molecular weight of less than 50 kDa. Despite the fact that the peptide profile was the same in both control animals and HM animals, the level of individual peptide fractions increased significantly in the rats with HM. Obtained data could contribute to explain, at least in part, the mechanisms involved in the pathogenesis of lung damage in hyperhomocysteinemia.

The growing demand for industrial proteases and enzyme-containing products substantiates the search for costeffective sources of enzymes. The aim of current research was to find a one-step approach for the isolation of the fraction of serine proteases from the jellyfish of the Antarctic region. Given our data, ion-exchange chromatography on diethylaminoethyl-sepharose carboxymethyl-sepharose was ineffective, in contrast to affinity chromatography on benzamidine-sepharose. The isolated fraction consists of enzymes with a molecular weight of more than 30 kDa and isoelectric points at pH = 3.0; 5.0-6.0 and pH = 9.0, which can break down gelatin, casein, and fibrinogen. The maximal proteolytic activity was found at pH = 12.0 and a temperature of +55°C. Serine proteases showed activity against the chromogenic substrate for trypsin and had no activity against substrates for chymotrypsin and elastase indicating that enzymes are trypsin-like proteases. The presence of enzymes with fibrino(geno)lytic activity and the ability of serine proteases from jellyfish to work at high pH and temperatures suggest their potential use as thrombolytics, as well as agents in the industries requiring a highly alkaline conditions.

The study presents the extraction of collagen, a product of high value, from fleshings form hides. After testing several collagen extraction procedures we have proposed the simple and effective method to extract collagen from collagen-containing wastes of the leather industry. The unified method is based on the extraction of collagen using acetic acid in the presence of EDTA and included two repeated extraction stages. Qualitative analysis of the collagen using the disk-electrophoresis method showed a different ratio of monomers, dimers and other proteins.