Characteristics of Reconstituted Collagen Fibers from Chicken Keel Cartilage Depends on Salt Type for Removal of Proteoglycans.

The aim of the presented research was to obtain reconstituted atelocollagen fibers after extraction from poultry cartilage using the pepsin-acidic method in order to remove telopeptides from the tropocollagen. Firstly, we examined the extraction of collagen from the cartilage extracellular matrix (ECM) after proteoglycans (PG) had been removed by the action of salts, i.e., NaCl or chaotropic MgCl2. Additionally, the effects of the salt type used for PG and hyaluronic acid removal on the properties of self-assembled fibers in solutions at pH 7.4 and freeze-dried matrices were investigated. The basic features of the obtained fibers were characterized, including thermal properties using scanning calorimetry, rheological properties using dynamic oscillatory rheometry, and the structure by scanning electron microscopy. The fibers obtained after PG removal with both analyzed types of salts had similar thermal denaturation characteristics. However, the fibers after PG removal with NaCl, in contrast to those obtained after MgCl2 treatment, showed different rheological properties during gelatinization and smaller diameter size. Moreover, the degree of fibrillogenesis of collagens after NaCl treatment was complete compared to that with MgCl2, which was only partial (70%). The structures of fibers after lyophilization were fundamentally different. The matrices obtained after NaCl pretreatment form regular scaffolds in contrast to the thin, surface structures of the cartilage matrix after proteoglycans removal using MgCl2.

Measuring digital transformation stress at the workplace-Development and validation of the digital transformation stress scale.

Despite the unquestionable advantages of digital transformation (DT) in organizations, the very process of DT could have an impact on the level of stress of the employees. The negative effects of the digital transformation process can be observed during the implementation of information and communication technologies (ICT) solutions. They are further enhanced by the effects of COVID-19 pandemic, as digital transformation has accelerated to allow for remote work. Herein we distinguish between general stress at the workplace and the very specific type of stress, namely digital transformation stress (DTS). We assumed that this type of stress appears when rapid implementation of ICT solutions is introduced with time pressure and incertitude of further results. To quantify this phenomenon, we developed a new self-report scale-the Digital Transformation Stress Scale (DTSS), measuring employees' stress stemming from the process of digital transformation in organizations. The psychometric validity of the scale was evaluated in two studies: Study1 conducted at the beginning of COVID-19 pandemic in 2020 (N = 229) and Study 2 in 2021 (N = 558), after a year of mostly remote work. The results confirmed good reliability with Cronbach's Alpha α = .91 in Study 1 and α = .90 in Study 2 and assumed unidimensional factorial validity of the scale in both studies. All items of the scale had good difficulty and discrimination values evaluated in Item Response Theory, i.e., IRT approach. The scale showed predicted convergent validity as the indicator of the digital transformation stress moderately correlated with general stress at work. Moreover, the assumption that even employees with high ICT skills could be affected by DTS was confirmed. Additionally, the results indicated that digital transformation stress was significantly higher among employees who reported both issues: ongoing digital solutions projects at the workplace and high impact of COVID-19 pandemic on their work. The scale could be used in future work on measuring and counteracting digital transformation stress at the workplace.

Dipeptide Extract Modulates the Oxi-Antioxidant Response to Intense Physical Exercise.

Exposure to intense physical exercise increases reactive oxygen and nitrogen species production. The process can be modulated by dipeptide bioavailability with antioxidant scavenger properties. The effects of dipeptide intake in combination with physical exercise on the oxi-antioxidant response were examined in a randomized and placebo-controlled trial. Blood samples were collected from 20 males aged 21.2 ± 1.8 years before and after 14-day intake of chicken breast extract (4 g/day), which is a good source of bioactive dipeptides. A significant increase in the NO/H2O2 ratio was observed in the 1st and 30th minute after intense incremental exercise in dipeptides compared to the placebo group. Total antioxidant and thiol redox status were significantly higher in the dipeptide group both before and after exercise; η2 ≥ 0.64 showed a large effect of dipeptides on antioxidant and glutathione status. The level of 8-isoprostanes, markers of oxidative damage, did not change under the influence of dipeptides. By contrast, reduced C-reactive protein levels were found during the post-exercise period in the dipeptide group, which indicates the anti-inflammatory properties of dipeptides. High pre-exercise dipeptide intake enhances antioxidant status and thus reduces the oxi-inflammatory response to intense exercise. Therefore, the application of dipeptides seems to have favourable potential for modulating oxidative stress and inflammation in physically active individuals following a strenuous exercise schedule.

Antioxidative Characteristics of Chicken Breast Meat and Blood after Diet Supplementation with Carnosine, L-histidine, and ß-alanine.

The objective of the study was to test the effect of diets supplemented with ß-alanine, L-histidine, and carnosine on the histidine dipeptide content and the antioxidative status of chicken breast muscles and blood. One-day-old Hubbard Flex male chickens were assigned to five treatments: control diet (C) and control diet supplemented with 0.18% L-histidine (ExpH), 0.3% ß-alanine (ExpA), a mix of L-histidine\ß-alanine (ExpH+A), and 0.27% carnosine (ExpCar). After 28 days, chicken breast muscles and blood samples were analyzed for the antioxidant enzyme activity (catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD)), carnosine and anserine content, amino acid profile, and anti-radical activity (ABTS, DPPH, ferric reducing antioxidant power (FRAP)). The results of the study showed that carnosine supplementation effectively increased body weight and breast muscle share in chicken carcasses. Carnosine and L-histidine supplementation with or without ß-alanine increased carnosine content in chicken breast muscles up to 20% (p = 0.003), but the boost seems to be too low to affect the potential antioxidant capacity and amino acid content. The ß-alanine-enriched diet lowered dipeptide concentration in chicken blood serum (p = 0.002) and activated catalase in chicken breast muscles in relation to the control group (p = 0.003). It can be concluded that histidine or dipeptide supplementation of chicken diets differently affected the total antioxidant potential: in breast muscles, it increased dipeptide content, while in blood cell sediment (rich in erythrocytes), increased SOD and GPx activities were observed.

New keratinolytic bacteria in valorization of chicken feather waste.

There is an increasing demand for cost-effective and ecologically-friendly methods for valorization of poultry feather waste, in which keratinolytic bacteria present a great potential. Feather-degrading bacteria were isolated from living poultry and a single strain, identified as Kocuria rhizophila p3-3, exhibited significant keratinolytic properties. The bacterial strain effectively degraded up to 52% of chicken feathers during 4 days of culture at 25 °C. Zymographic analysis revealed the presence of two dominating proteolytic enzymes in the culture fluid. Culture conditions were optimized in order to maximize the liberation of soluble proteins and free amino acids. A two-step procedure was used, comprising a Plackett-Burman screening design, followed by a Box-Behnken design. Concentration of feather substrate, MgSO4 and KH2PO4 were the most influential parameters for the accumulation of soluble proteins in culture K. rhizophila p3-3, while feathers and MgSO4 also affected the concentration of amino acids. The resultant raw hydrolysate supernatant, prior to and after additional treatments, was rich in phenylalanine, histidine, arginine and aspartic acid. Additionally the hydrolysate exhibited radical-scavenging activity and ferric reducing power.

Actin content and actin polymerization in hepatoma Morris 5123 tumor bearing rats after treatment with cysteine protease inhibitor and vitamin E.

AIM: Actin microfilaments are components of cytoskeleton, the structure involved in many cellular functions, including cell motility, and morphology, its necessary for tumor progression and metastasis. We investigated the effects of vitamin E and human placetal cysteine protease inhibitor (CPI) on actin content and polymerization after implantation the hepatoma Morris 5123 tumor in Buffalo rat. METHODS: We measured the size and survival animals treated with human placental cysteine protease inhibitor (CPI) plus vitamin E and none treated rats. Also measured the actin content and polymerization in the tumor and liver tissues by the inhibition of DNase I from bovine pancreas under standard assay conditions RESULTS: We observed that the combination 10 mg of vitamin E plus 200 microg CPI obtained the best results than authors. In those cases the animals survived for longer than 4 weeks. In numerous cases the 70 % of tumors disappeared following CPI and vitamin E application. The number of complete tumor responses was higher after combination 10 mg of vitamin E plus CPI 200 microg i.e. 5/7 rats than others group. We showed statistically significant decrease of monomeric (G), filamentous (F) and total actin as well as the F:G ratio level in tumor tissues after the rats was treated with CPI plus vitamin E in comparison with control animals. CONCLUSIONS: The new therapy may be the way for therapeutic intervention, aimed at stopping and possibly reversing the process of metastatic growth, with the use of drugs affecting actin polymerization.

Expression of cystatin C in clinical human colorectal cancer tissues.

We studied the relation between the antipapain activity of cysteine proteinase inhibitors (CPI) and immunohistochemical staining for cystatin C, using anti-chicken cystatin antibodies, in the colorectal cancer tissues. In primary tumour tissues immuno-peroxidase reactivity was present in the cytoplasm and on the cell surface membranes. Sections of non malignant tissues showed no staining. The percentages of positive staining were greater for adenocarcinoma than carcinoma,100% and 77% respectively. Antipapain activity which was increased in malignant tissues in comparison to control, rose successively from well differentiated carcinomas through moderately to poor differentiated. Invasive adenocarcinomas had higher antipapain activity than noninvasive ones. The results indicated that immunohistochemical detection of cystatin using anti-chicken cystatin antibodies could be useful in studying the prognostic significance of cystatin C expression in colorectal cancer.