Comprehensive study upon physicochemical properties of bio-ZnO NCs.

In this study, for the first time, the comparison of commercially available chemical ZnO NCs and bio-ZnO NCs produced extracellularly by two different probiotic isolates (Latilactobacillus curvatus MEVP1 [OM736187] and Limosilactobacillus fermentum MEVP2 [OM736188]) were performed. All types of ZnO formulations were characterized by comprehensive interdisciplinary approach including various instrumental techniques in order to obtain nanocomposites with suitable properties for further applications, i.e. biomedical. Based on the X- ray diffraction analysis results, all tested nanoparticles exhibited the wurtzite structure with an average crystalline size distribution of 21.1 nm (CHEM_ZnO NCs), 13.2 nm (1C_ZnO NCs) and 12.9 nm (4a_ZnO NCs). The microscopy approach with use of broad range of detectors (SE, BF, HAADF) revealed the core-shell structure of bio-ZnO NCs, compared to the chemical one. The nanoparticles core of 1C and 4a_ZnO NCs are coated by the specific organic deposit coming from the metabolites produced by two probiotic strains, L. fermentum and L. curvatus. Vibrational infrared spectroscopy, photoluminescence (PL) and mass spectrometry (LDI-TOF-MS) have been used to monitor the ZnO NCs surface chemistry and allowed for better description of bio-NCs organic coating composition (amino acids residues). The characterized ZnO formulations were then assessed for their photocatalytic properties against methylene blue (MB). Both types of bio-ZnO NCs exhibited good photocatalytic activity, however, the effect of CHEM_ZnO NCs was more potent than bio-ZnO NCs. Finally, the colloidal stability of the tested nanoparticles were investigated based on the zeta potential (ZP) and hydrodynamic diameter measurements in dependence of the nanocomposites concentration and investigation time. During the biosynthesis of nano-ZnO, the increment of pH from 5.7 to around 8 were observed which suggested possible contribution of zinc aquacomplexes and carboxyl-rich compounds resulted in conversion of zinc tetrahydroxy ion complex to ZnO NCs. Overall results in present study suggest that used accessible source such us probiotic strains, L. fermentum and L. curvatus, for extracellular bio-ZnO NCs synthesis are of high interest. What is important, no significant differences between organic deposit (e.g. metabolites) produced by tested strains were noticed-both of them allowed to form the nanoparticles with natural origin coating. In comparison to chemical ZnO NCs, those synthetized via microbiological route are promising material with further biological potential once have shown high stability during 7 days.

CE-DAD-MS/MS in the simultaneous determination and identification of selected antibiotic drugs and their metabolites in human urine samples.

In this study, a new analytical method was developed and validated for the simultaneous analysis of antibiotic drugs (amoxicillin, cefotaxime, ciprofloxacin, clindamycin, linezolid, metronidazole) and their metabolites (amoxycilloic acid, amoxicillin diketopiperazine, 3-desacetyl cefotaxime lactone, clindamycin sulfoxide, ciprofloxacin piperazinyl-N4-sulfate, linezolid N-oxide, metronidazole-OH) in human urine. Capillary electrophoresis (CE) along with the tandem mass spectrometry (MS/MS) was used to determine and identify all analytes. Appropriate conditions for MS/MS measurements along with the use of the central composite design were optimized. The effects of different analytical conditions (the composition, the concentration, and the pH value of the background electrolyte, the time and pressure of the injection, the capillary temperature and influence of the organic modifier) on the migration and separation of antibiotic drugs and metabolites were examined using the CE-DAD. The analytical procedure was linear for concentrations ranging from 20 to 1000 ng/mL, with determination coefficients higher than 0.99 for all the analytes. The validated analytical procedure was then applied to the measurement of antibiotic drugs and their metabolites in human urine samples.

[Long lasting symptoms of dyspnea, cough and fatigue after COVID-19 - narrative review of epidemiological studies]. / Dlugo utrzymujace sie objawy dusznosci, kaszlu i zmeczenia po przebyciu COVID-19 ­ przeglad narracyjny badan epidemiologicznych.

"Long-COVID" is described as long-term effects of SARS­ CoV­2 infection that last >4 weeks after the acutephase of infection. The aim of this narrative reviews to evaluate the frequency of occurrence of 3 symptoms often observed in Long-COVID, i.e., chronic fatigue, shortness of breath and cough, and whether comorbidities such as diabetes and arterial hypertension increase the risk of complications after a history of SARS­ CoV­2 infection. The method of narrative review was used in this paper. PubMed (May 31, 2021) search was performed to retrieve articles concerning the occurrence of long COVID-19 chronic fatigue, dyspnoea and chronic cough. Studies in which the observation period was <30 days and the average age of subjects exceeded 60 years, as well as studies with no information on the methodology used, in particular without the method of recruiting people for the study, were excluded. Populations with a high frequency of diabetes were defined as the prevalence >10%, and in the case of arterial hypertension >40%. The average frequency of diabetes <10%, hypertension 40%. It can be concluded that in the period of >30 days after discharge from the hospital, in populations with a high incidence of diabetes and hypertension, the incidence of chronic fatigue and cough was higher than in the other analyzed groups. Symptoms of dyspnea were most frequently reported in populations with high rates of diabetes, but at the same time in the average percentage of people with arterial hypertension. Persistent symptoms specific to "Long-COVID" can significantly reduce the ability to perform work. In this situation, check-ups performed before returning to work after long-term leave tape on a new dimension. Med Pr. 2021;72(6):711-20.

Comparison Study of Cytotoxicity of Bare and Functionalized Zinc Oxide Nanoparticles.

In this paper, a study of the cytotoxicity of bare and functionalized zinc oxide nanoparticles (ZnO NPs) is presented. The functionalized ZnO NPs were obtained by various types of biological methods including microbiological (intra- and extracellular with Lactobacillus paracasei strain), phytochemical (Medicago sativa plant extract) and biochemical (ovalbumin from egg white protein) synthesis. As a control, the bare ZnO NPs gained by chemical synthesis (commercially available) were tested. The cytotoxicity was measured through the use of (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) dye as well as lactate dehydrogenase (LDH) assays against murine fibroblast L929 and Caco-2 cell lines. As a complementary method, scanning electron microscopy (SEM) was performed to assess the morphology of the tested cells after treatment with ZnO NPs. The microscopic data confirmed the occurrence of apoptotic blebbing and loss of membrane permeability after the administration of all ZnO NPs. The reactive oxygen species (ROS) concentration during the cell lines' exposure to ZnO NPs was measured fluorometrically. Additionally, the photocatalytic degradation of methylene blue (MB) dye in the different light conditions, as well as the antioxidant activity of bare and functionalized ZnO NPs, is also reported. The addition of all types of tested ZnO NPs to methylene blue resulted in enhanced rates of photo-degradation in the presence of both types of irradiation, but the application of UV light resulted in higher photocatalytic activity of ZnO NPs. Furthermore, bare (chemically synthetized) NPs have been recognized as the strongest photocatalysts. In the context of the obtained results, a mechanism underlying the toxicity of bio-ZnO NPs, including (a) the generation of reactive oxygen species and (b) the induction of apoptosis, is proposed.

The study of the molecular mechanism of Lactobacillus paracasei clumping via divalent metal ions by electrophoretic separation.

In this work, the molecular mechanism of Lactobacillus paracasei bio-colloid clumping under divalent metal ions treatment such as zinc, copper and magnesium at constant concentrations was studied. The work involved experimental (electrophoretic - capillary electrophoresis in pseudo-isotachophoresis mode, spectroscopic and spectrometric - FT-IR and MALDI-TOF-MS, microscopic - fluorescent microscopy, and flow cytometry) and theoretical (DFT calculations of model complex systems) characterization. Electrophoretic results have pointed out the formation of aggregates under the Zn2+ and Cu2+ modification, whereas the use of the Mg2+ allowed focusing the zone of L. paracasei biocolloid. According to the FT-IR analysis, the major functional groups involved in the aggregation are deprotonated carboxyl and amide groups derived from the bacterial surface structure. Nature of the divalent metal ions was shown to be one of the key factors influencing the bacterial aggregation process. Proteomic analysis showed that surface modification had a considerable impact on bacteria molecular profiles and protein expression, mainly linked to the activation of carbohydrate and nucleotides metabolism as well with the transcription regulation and membrane transport. Density-functional theory (DFT) calculations of modeled Cu2+, Mg2+ and Zn2+ coordination complexes support the interaction between the divalent metal ions and bacterial proteins. Consequently, the possible mechanism of the aggregation phenomenon was proposed. Therefore, this comprehensive study could be further applied in evaluation of biocolloid aggregation under different types of metal ions.

The Study on Molecular Profile Changes of Pathogens via Zinc Nanocomposites Immobilization Approach.

The most critical group of all includes multidrug resistant bacteria that pose a particular threat in hospitals, as they can cause severe and often deadly infections. Modern medicine still faces the difficult task of developing new agents for the effective control of bacterial-based diseases. The targeted administration of nanoparticles can enhance the efficiency of conventional pharmaceutical agents. However, the interpretation of interfaces' interactions between nanoparticles and biological systems still remains a challenge for researchers. In fact, the current research presents a strategy for using ZnO NPs immobilization with ampicillin and tetracycline. Firstly, the study provides the mechanism of the ampicillin and tetracycline binding on the surface of ZnO NPs. Secondly, it examines the effect of non-immobilized ZnO NPs, immobilized with ampicillin (ZnONPs/AMP) and tetracycline (ZnONPs/TET), on the cells' metabolism and morphology, based on the protein and lipid profiles. A sorption kinetics study showed that the antibiotics binding on the surface of ZnONPs depend on their structure. The efficiency of the process was definitely higher in the case of ampicillin. In addition, flow cytometry results showed that immobilized nanoparticles present a different mechanism of action. Moreover, according to the MALDI approach, the antibacterial activity mechanism of the investigated ZnO complexes is mainly based on the destruction of cell membrane integrity by lipids and proteins, which is necessary for proper cell function. Additionally, it was noticed that some of the identified changes indicate the activation of defense mechanisms by cells, leading to a decrease in the permeability of a cell's external barriers or the synthesis of repair proteins.

Isolation and Self-Association Studies of Beta-Lactoglobulin.

The aim of this study was to investigate isolated ß-lactoglobulin (ß-LG) from the whey protein isolate (WPI) solution using the column chromatography with SP Sephadex. The physicochemical characterization (self-association, the pH stability in various salt solutions, the identification of oligomeric forms) of the protein obtained have been carried out. The electrophoretically pure ß-LG fraction was obtained at pH 4.8. The fraction was characterized by the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/TOF MS) technique. The use of the HCCA matrix indicated the presence of oligomeric ß-LG forms, while the SA and DHB matrices enabled the differentiation of A and B isoforms in the sample. The impact of sodium chloride, potassium chloride, ammonium sulfate, and sodium citrate in dispersion medium on ß-LG electrophoretic stability in solution was also studied. Type of the dispersion medium led to the changes in the isoelectric point of protein. Sodium citrate stabilizes protein in comparison to ammonium sulfate. Additionally, the potential of capillary electrophoresis (CE) with UV detection using bare fused capillary to monitor ß-LG oligomerization was discussed. Obtained CE data were further compared by the asymmetric flow field flow fractionation coupled with the multi-angle light scattering detector (AF4-MALS). It was shown that the ß-LG is a monomer at pH 3.0, dimer at pH 7.0. At pH 5.0 (near the isoelectric point), oligomers with structures from dimeric to octameric are formed. However, the appearance of the oligomers equilibrium is dependent on the concentration of protein. The higher quantity of protein leads to the formation of the octamer. The far UV circular dichroism (CD) spectra carried out at pH 3.0, 5.0, and 7.0 confirmed that ß-sheet conformation is dominant at pH 3.0, 5.0, while at pH 7.0, this conformation is approximately in the same quantity as α-helix and random structures.

Zinc Oxide Nanocomposites-Extracellular Synthesis, Physicochemical Characterization and Antibacterial Potential.

This research presents, for the first time, the potential of the Lactobacillus paracasei LC20 isolated from sweet whey as a novel, effective and accessible source for post-cultured ZnO nanocomposites synthesis. The obtained nanocomposites were subjected to comprehensive characterization by a broad spectrum of instrumental techniques. Results of spectroscopic and microscopic analysis confirmed the hexagonal crystalline structure of ZnO in the nanometer size. The dispersion stability of the obtained nanocomposites was determined based on the zeta potential (ZP) measurements-the average ZP value was found to be -29.15 ± 1.05 mV in the 7-9 pH range. The ZnO nanocomposites (NCs) demonstrated thermal stability up to 130 °C based on the results of thermogravimetric TGA/DTG) analysis. The organic deposit on the nanoparticle surface was recorded by spectroscopic analysis in the infrared range (FT-IR). Results of the spectrometric study exhibited nanostructure-assisted laser desorption/ionization effects and also pointed out the presence of organic deposits and, what is more, allowed us to identify the specific amino acids and peptides present on the ZnO NCs surfaces. In this context, mass spectrometry (MS) data confirmed the nano-ZnO formation mechanism. Moreover, fluorescence data showed an increase in fluorescence signal in the presence of nanocomposites designed for potential use as, e.g., biosensors. Despite ZnO NCs' luminescent properties, they can also act as promising antiseptic agents against clinically relevant pathogens. Therefore, a pilot study on the antibacterial activity of biologically synthesized ZnO NCs was carried out against four strains (Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa) by using MIC (minimal inhibitory concentration). Additionally, the colony forming units (CFU) assay was performed and quantified for all bacterial cells as the percentage of viable cells in comparison to a control sample (untreated culture) The nanocomposites were effective among three pathogens with MIC values in the range of 86.25-172.5 µg/mL and showed potential as a new type of, e.g., medical path or ointment formulation.