Sources of competitive advantage of enterprises in selected sectors of the Polish economy

PURPOSE: Study impact of business activities on selection of sources of enterprises’ competitive advantage. The research hypothesis is advanced as H1: scope of business objects (sector) is a factor differentiating selection of sources of competitive advantage by enterprises. The concept and essence of competitiveness are discussed, methods of building competitive advantage by enterprises are detailed.DESIGN/METHODOLOGY/APPROACH: The theoretical section follows a comprehensive review of leading specialist literature. The hypothesis is verified in the empirical section by means of position measures (arithmetic mean, median) and variability measures (standard deviation, coefficient of variability). Kruskal-Wallis test is also used to verify the research hypothesis.FINDINGS: The paper contains results of a survey of 253 large Polish enterprises. KruskalWallis test serves to determine impact of a sector on selection of sources of enterprise competitive advantage. Sector has no effect on choice of such sources as: quality management system, cost reduction, advertising, public relations, enterprise image, highly qualified managerial staff, knowledge and skills of employees, new technologies, or customer trust.PRACTICAL IMPLICATIONS: The results can be utilised by enterprises as guidelines for selection of sources of competitive advantage.ORIGINALITY/VALUE: The paper contains an original study of a representative group of large enterprises that can be generalised to the whole population assuming a confidence level α=95% and maximum error β=6%.peer-reviewe

Characterization of the newly isolated lytic bacteriophages KTN6 and KT28 and their efficacy against Pseudomonas aeruginosa biofilm

We here describe two novel lytic phages, KT28 and KTN6, infecting Pseudomonas aeruginosa, isolated from a sewage sample from an irrigated field near Wroclaw, in Poland. Both viruses show characteristic features of Pbunalikevirus genus within the Myoviridae family with respect to shape and size of head/tail, as well as LPS host receptor recognition. Genome analysis confirmed the similarity to other PB1-related phages, ranging between 48 and 96%. Pseudomonas phage KT28 has a genome size of 66,381 bp and KTN6 of 65,994 bp. The latent period, burst size, stability and host range was determined for both viruses under standard laboratory conditions. Biofilm eradication efficacy was tested on peg-lid plate assay and PET membrane surface. Significant reduction of colony forming units was observed (70-90%) in 24 h to 72 h old Pseudomonas aeruginosa PAO1 biofilm cultures for both phages. Furthermore, a pyocyanin and pyoverdin reduction tests reveal that tested phages lowers the amount of both secreted dyes in 48-72 h old biofilms. Diffusion and goniometry experiments revealed the increase of diffusion rate through the biofilm matrix after phage application. These characteristics indicate these phages could be used to prevent Pseudomonas aeruginosa infections and biofilm formation. It was also shown, that PB1-related phage treatment of biofilm caused the emergence of stable phage-resistant mutants growing as small colony variants

Interaction of human mannose-binding lectin (MBL) with Yersinia enterocolitica lipopolysaccharide

tThe lipopolysaccharide (LPS) is involved in the interaction between Gram-negative pathogenic bacteriaand host. Mannose-binding lectin (MBL), complement-activating soluble pattern-recognition receptortargets microbial glycoconjugates, including LPS. We studied its interactions with a set of Yersinia ente-rocolitica O:3 LPS mutants. The wild-type strain LPS consists of lipid A (LA) substituted with an inner coreoligosaccharide (IC) which in turn is substituted either with the O-specific polysaccharide (OPS) or theouter core hexasaccharide (OC), and sometimes also with the enterobacterial common antigen (ECA). TheLPS mutants produced truncated LPS, missing OPS, OC or both, or, in addition, different IC constituentsor ECA. MBL bound to LA-IC, LA-IC-OPS and LA-IC-ECA but not LA-IC-OC structures. Moreover, LA-IC sub-stitution with both OPS and ECA prevented the lectin binding. Sequential truncation of the IC heptosesdemonstrated that the MBL targets the IC heptose region. Furthermore, microbial growth temperatureinfluenced MBL binding; binding was stronger to bacteria grown at room temperature (22◦C) than to bac-teria grown at 37◦C. In conclusion, our results demonstrate that MBL can interact with Y. enterocoliticaLPS, however, the in vivo significance of that interaction remains to be elucidated

Zirconium-based metal–organic frameworks as acriflavine cargos in the battle against coronaviruses : a theoretical and experimental approach

[Image: see text] In this study, we present a complementary approach for obtaining an effective drug, based on acriflavine (ACF) and zirconium-based metal–organic frameworks (MOFs), against SARS-CoV-2. The experimental results showed that acriflavine inhibits the interaction between viral receptor-binding domain (RBD) of spike protein and angiotensin converting enzyme-2 (ACE2) host receptor driving viral cell entry. The prepared ACF@MOF composites exhibited low (MOF-808 and UiO-66) and high (UiO-67 and NU-1000) ACF loadings. The drug release profiles from prepared composites showed different release kinetics depending on the local pore environment. The long-term ACF release with the effective antiviral ACF concentration was observed for all studied ACF@MOF composites. The density functional theory (DFT) calculations allowed us to determine that π–π stacking together with electrostatic interaction plays an important role in acriflavine adsorption and release from ACF@MOF composites. The molecular docking results have shown that acriflavine interacts with several possible binding sites within the RBD and binding site at the RBD/ACE2 interface. The cytotoxicity and ecotoxicity results have confirmed that the prepared ACF@MOF composites may be considered potentially safe for living organisms. The complementary experimental and theoretical results presented in this study have confirmed that the ACF@MOF composites may be considered a potential candidate for the COVID-19 treatment, which makes them good candidates for clinical trials

Serological characterization of the enterobacterial common antigen substitution of the lipopolysaccharide of "Yersinia enterocolitica" O:3

Enterobacterial common antigen (ECA) is a polysaccharide present in all members of Enterobacteriaceae anchored either via phosphatidylglycerol (PG) or LPS to the outer leaflet of the outer membrane (ECAPG and ECALPS, respectively). Only the latter form is ECAimmunogenic. We previously demonstrated that Yersinia enterocolitica O: 3 and its rough (Ospecific polysaccharide-negative) mutants were ECA-immunogenic, suggesting that they contained ECALPS; however, it was not known which part of the LPS core region was involved in ECA binding. To address this, we used a set of three deep-rough LPS mutants for rabbit immunization. The polyvalent antisera obtained were: (i) analysed for the presence of anti-LPS and anti-ECA antibodies; (ii) treated with caprylic acid (CA) to precipitate IgM antibodies and protein aggregates; and (iii) adsorbed with live ECA-negative bacteria to obtain specific anti-ECA antisera. We demonstrated the presence of antibodies specific for both ECAPG and ECALPS in all antisera obtained. Both CA treatment and adsorption with ECA-negative bacteria efficiently removed anti-LPS antibodies, resulting in specific anti-ECA sera. The LPS of the ECALPS-positive deepest-rough mutant contained only lipid A and 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo) residues of the inner core, suggesting that ECALPS was linked to the Kdo region of LPS in Y. enterocolitica O:3

Nivolumab for relapsed/refractory classical Hodgkin lymphoma after brentuximab vedotin failure – Polish Lymphoma Research Group real-life experience

AimPolish centers analyzed retrospectively the real-life experience with nivolumab in relapsed/refractory (R/R) classical Hodgkin lymphoma (cHL) patients, after brentuximab vedotin (BV ) failure. BackgroundDespite the effective frontline treatment, for cHL patients relapsing after autologous stem cell transplantation, the only effective strategy remains the novel agents. Nivolumab, a checkpoint inhibitor, demonstrates the clinical benefit with an acceptable safety profile. Materials and methodsRetrospective analysis included 16 adult patients with R/R cHL after BV failure. All patients received single-agent nivolumab 3 mg/kg every 2 weeks until disease progression or unacceptable toxicity. ResultsAfter six cycles of nivolumab the overall response rate was 81% (complete remission rate of 56%, partial remission rate of 25%). The median PFS was not reached after a median follow-up of 19 months. Adverse events (AEs) of any grade occurred in 12 patients (75%), including grade 3 AEs observed in 5 patients (31%). There were no AEs of grade 4 or 5. After a median of 25 nivolumab doses, 62% of responding patients proceeded to allogeneic stem cell transplantation. ConclusionNivolumab monotherapy demonstrated a high efficacy and safety in R/R cHL patients after BV failure. More patients and longer follow-up may further establish the potential benefit