Integration of Ultra- and Nanofiltration for Potato Processing Water (PPW) Treatment in a Circular Water Recovery System.

The article analyzes integrated ultrafiltration (UF) and nanofiltration (NF) processes for potato processing wastewater treatment for the purpose of which a laboratory filtration system for flat sheet membranes with the effective surface area of 1.4 × 10-2 m2 (UF: polysulfone, cut-off: 10,000 Da; NF: polypiperazine amide, cut-off: 150-300 Da) was used. As part of the study, the effect of the transmembrane pressure of UF (0.2 MPa and 0.4 MPa) and NF (1.0 MPa and 1.8 MPa) on the permeate flux and rejection coefficient was investigated and the impact of sewage preparation methods on the degree of pollution reduction was determined. Moreover, a method for a fouling layer removal from the UF membranes is also proposed. The results of the analyses conducted by the authors show that the pretreatment stage offers additional advantages to TSS and turbidity removal. In both cases (0.2 and 0.4 MPa), UF used after the pretreatment process resulted in a 97-99% reduction in these impurities. The analysis of the determined rejection coefficients shows that the use of NaOH and H2O2 for the regeneration of the UF membrane has a positive effect on filtration efficiency. Regarding NF, the rejection coefficients for most tested parameters were higher for the 1.8 MPa process compared to 1.0 MPa, and approximately 80% of water was recovered.

Second Generation Amphiphilic Poly-Lysine Dendrons Inhibit Glioblastoma Cell Proliferation without Toxicity for Neurons or Astrocytes.

Glioblastomas are the most common malignant primary brain tumours in adults and one of the most aggressive and difficult-to-treat cancers. No effective treatment exits actually for this tumour and new therapeutic approaches are needed for this disease. One possible innovative approach involves the nanoparticle-mediated specific delivery of drugs and/or genetic material to glioblastoma cells where they can provide therapeutic benefits. In the present work, we have synthesised and characterised several second generation amphiphilic polylysine dendrons to be used as siRNA carriers. We have found that, in addition to their siRNA binding properties, these new compounds inhibit the proliferation of two glioblastoma cell lines while being nontoxic for non-tumoural central nervous system cells like neurons and glia, cell types that share the anatomical space with glioblastoma cells during the course of the disease. The selective toxicity of these nanoparticles to glioblastoma cells, as compared to neurons and glial cells, involves mitochondrial depolarisation and reactive oxygen species production. This selective toxicity, together with the ability to complex and release siRNA, suggests that these new polylysine dendrons might offer a scaffold in the development of future nanoparticles designed to restrict the proliferation of glioblastoma cells.

Novel dendrimeric lipopeptides with antifungal activity.

A series of new cationic lipopeptides containing branched, amphiphilic polar head derived from (Lys)Lys(Lys) dendron and C(8) or C(12) chain at C-end were designed, synthesized and characterized. Antimicrobial in vitro activity expressed as minimal inhibitory concentration (MIC) was evaluated against Gram-positive and Gram-negative bacteria and yeasts from the Candida genus. A significant enhancement of antimicrobial potency along with increased selectivity against Candida reference strains was detected for derivatives with the C(12) residue. Several compounds were characterized by a low hemotoxicity. The antifungal activity of branched lipopeptides is multimodal and concentration dependent. Several compounds, studied in detail, induced potassium leakage from fungal cells, caused morphological alterations of fungal cells and inhibited activity of candidal ß(1,3)-glucan synthase.

Amphiphilic dendrimeric peptides as model non-sequential pharmacophores with antimicrobial properties.

A concept of application of dendrimer chemistry for construction of 'non-sequential pharmacophore', mimicking active conformation of linear antimicrobial peptides, is introduced. It resulted in the synthesis of a family of low- molecular-weight basic peptide dendrimers with antimicrobial properties against Staphylococcus aureus (Gram-positive), Escherichia coli (Gram-negative) and Candida albicans.

The interaction between polycationic poly-lysine dendrimers and charged and neutral fluorescent probes.

The interactions between polycationic poly-lysine dendrimers and hydrophobic fluorescent probes (anionic ANS and neutral Prodan) were studied. R121 and R131 dendrimers were not able to interact with anionic and neutral hydrophobic groups. R124 was able to interact with neutral and anionic hydrophobic fluorescent probes, however mainly through hydrophobic forces. Dendrimers R155 and R169 showed the maximal effects. The strongest interactions observed for R169 can be explained by intramolecular folding (stacking) of its two L-proline residues. Using double fluorescence titration technique for ANS probe allowed to receive such constant of binding and the number of binding centers: for R121, 1.8 x 10(3) (mol/l)(-1) and 1.07; for R124, 12.1 x 10(3) (mol/l)(-1) and 0.48; for R131, 4.7 x 10(3) (mol/l)(-1) and 0.48; for R155, 9.2 x 10(3) (mol/l)(-1) and 1.36; for R169, 39.6 x 10(3) (mol/l)(-1) and 0.97. Thus, neutral and anionic hydrophobic probes can be used for the fast preliminary screening of binding properties of newly synthesized polycationic dendrimers.

Synthesis, antimicrobial activity and structural studies of low molecular mass lysine dendrimers.

Four low molecular mass lysine dendrimers were synthesized by Boc chemistry in solution (155 and 169) and Fmoc chemistry on solid support (P2 and P13). The structure and fragmentation mode of the above dendrimers was investigated in gas phase by the LSI-MS and ESI-MS techniques. (1)H and (13)C NMR analysis in solution (d(6)-DMSO) allowed to confirm the correct structure. Antimicrobial activities of the dendrimers against Staphylococcus aureus, Escherichia coli and Candida albicans confirmed our hypothesis that the dendrimer structure can be used for construction of molecules interacting with biological membranes.

Low molecular mass peptide dendrimers that express antimicrobial properties.

A series of low-generation dendrimeric peptides was synthesized in an attempt to evaluate their antimicrobial potency. All tested dendrimeric peptides in which lysine was a starting and branching element expressed moderate activity against Staphylococcus aureus NCTC 4163, and Escherichia coli NCTC 8196.