Interaction of the bacteriocin pediocin SJ-1 with the cytoplasmic membrane of sensitive bacterial cells as detected by ANS fluorescence

A bioactivated in vivo assembly nanotechnology fabricated NIR probe for small pancreatic tumor intraoperative imaging

Real-time imaging of the tumour boundary is important during surgery to ensure that sufficient tumour tissue has been removed. However, the current fluorescence probes for bioimaging suffer from poor tumour specificity and narrow application of the imaging window used. Here, we report a bioactivated in vivo assembly (BIVA) nanotechnology, demonstrating a general optical probe with enhanced tumour accumulation and prolonged imaging window. The BIVA probe exhibits active targeting and assembly induced retention effect, which improves selectivity to tumours. The surface specific nanofiber assembly on the tumour surface increases the accumulation of probe at the boundary of the tumor. The blood circulation time of the BIVA probe is prolonged by 110 min compared to idocyanine green. The assembly induced metabolic stability broaden the difference between the tumor and background, obtaining a delayed imaging window between 8-96 h with better signal-to-background contrast (>9 folds). The fabricated BIVA probe permits precise imaging of small sized (<2 mm) orthotopic pancreatic tumors in vivo. The high specificity and sensitivity of the BIVA probe may further benefit the intraoperative imaging in a clinical setting.

Alternative “Green” Antimicrobial Agents Obtained by Selective Sorption from Lactobacillus plantarum Culture

According to the world health organization report from September 2016, the development of pathogenic bacteria resistance to antimicrobial drugs is one of the most important problems of the modern medicine. In this regard, the urgent task is the search for alternative antibiotics for the treatment of bacterial infections. One approach to solving this problem is obtaining antimicrobial compounds synthesized by probiotic lactic acid bacteria. The probiotic strain of Lactobacillus plantarum 8P-A3, was chosen to study its antimicrobial action. This strain produces at least two bacteriocins – plantaricin EF and plantaricin NC8. The chromatographic isolation of peptide fractions from the supernatant was carried out using a polymer sorbent based on methacrylic acid and ethyleneglycol dimethacrylate. Optimal parameters for chromatographic process were determined. It is shown that all the target biologically active substances were bound with the sorbent in sorption at acidic pH values. Elution was performed in isocratic mode. The antimicrobial activity of the obtained peptide fractions against indicator culture was determined by turbidimetric method. During incubation process, the turbidity of the microbial suspension was determined by measuring the optical density at λ = 600 nm. It is revealed that the fraction obtained at rinse by eluent with pH 8 has the maximum inhibitory ability. Сhromatomass-spectrometry analysis of the peptide fraction was carried out using Shimadzu LCMS-8040.The antimicrobial activity of the fraction is comparable to the action of ampicillin against gram-negative bacteria Escherichia coli. To confirm the peptide nature of the antimicrobial activity of the fraction, an indicator culture was incubated with the fraction treated with proteolytic enzymes (trypsin). It is determined the fraction can be stored at −18 °C and saves antimicrobial properties after defrosting.