Antimicrobial activity and properties of de novo design of short synthetic lipopeptides.

The aim of this article is to introduce the topic of newly designed peptides as well as their biological activity. We designed nine encoded peptides composed of six amino acids. All these peptides were synthesized with C-terminal amidation. To investigate the importance of increased hydrophobicity at the amino end of the peptides, all of them were subsequently synthesized with palmitic or lithocholic acid at the N-terminus. Antimicrobial activity was tested on Gram-positive and Gram-negative bacteria and fungi. Cytotoxicity was measured on HepG2 and HEK 293 T cell cultures. Peptides bearing a hydrophobic group exhibited the best antimicrobial activity. Lipopeptides with palmitic or lithocholic acid (PAL or LCA peptides) at the N-terminus and with C-terminal amidation were highly active against Gram-positive bacteria, especially against strains of Staphylococcus aureus and Candida tropicalis. The LCA peptide SHP 1.3 with the sequence LCA-LVKRAG-NH2, had high efficiency on HepG2 human liver hepatocellular carcinoma cells (97%).

Noble metal nanoparticles in agriculture: impacts on plants, associated microorganisms, and biotechnological practices.

Within the past decades, nanoparticles (NPs) have become common components of electronics, batteries, cosmetics, clothing, and even dietary supplements. Despite their undisputed advantages consisting in the possibility of engineering their novel physical, thermal, optical, and biological properties, safety questions arise concerning their wide exploitation. NPs interact with living organisms, which can interfere with essential life processes. The aim of this paper is to critically review the current literature dealing with noble metals' NPs (NM-NPs) and their effects on plants and associated microorganisms. Particular attention has been given to the less studied NPs of platinum group elements, which can be considered a neglected pollutant, since they are released from vehicles' catalysts. In addition, we have provided a comprehensive overview of the biotechnology exploitation of NM-NPs in plant cultivation, where prospective nanomaterials developed as nanofertilizers and nanopesticides are introduced, and both the pros and the cons of nanomaterial plant treatments have been discussed.

Genomic Damage Induced in Nicotiana tabacum L. Plants by Colloidal Solution with Silver and Gold Nanoparticles.

Tobacco seedlings (Nicotiana tabacum L cv. Wisconsin 38) were treated for 24 h with colloidal solution of silver and gold nanoparticles (AgNPs and AuNPs) of different size or cultivated for 8 weeks on soil polluted with these NPs. DNA damage in leaf and roots nuclei was evaluated by the comet assay. AgNPs of the size 22-25 nm at concentrations higher than 50 mg·L-1 significantly increased the tail moments (TM) values in leaf nuclei compared to the negative control. Ag nanoparticles of smaller size 12-15 nm caused a slight increase in tail moment without significant difference from the negative control. The opposite effect of AgNPs was observed on roots. The increasing tail moment was registered for smaller NPs. Similar results were observed for AuNPs at a concentration of 100 mg·L-1. DNA damaging effects after growing tobacco plants for 8 weeks in soil polluted with AgNPs and AuNPs of different size and concentrations were observed. While lower concentrations of both types of particles had no effect on the integrity of DNA, concentration of 30 mg·kg-1 of AgNPs caused significant DNA damage in leaves of tobacco plants. AuNPs had no effect even at the highest concentration. The content of Ag was determined by ICP-MS in above-ground part of plants (leaves) after 8 weeks of growth in soil with 30 mg·kg-1. AgNPs and was 2.720 ± 0.408 µg·g-1. Long term effect is much less harmful probably due to the plant restoration capability.

Decorative Magnolia Plants: A Comparison of the Content of Their Biologically Active Components Showing Antimicrobial Effects.

Magnolia plants are used both as food supplements and as cosmetic and medicinal products. The objectives of this work consisted of preparing extracts from leaves and flowers of eight Magnolia plants, and of determining concentrations of magnolol (1 to 100 mg·g-1), honokiol (0.11 to 250 mg·g-1), and obovatol (0.09 to 650 mg·g-1), typical neolignans for the genus Magnolia, in extracts made by using a methanol/water (80/20) mixture. The tested Magnolia plants, over sixty years old, were obtained from Pruhonický Park (Prague area, Czech Republic): M. tripetala MTR 1531, M. obovata MOB 1511, and six hybrid plants Magnolia × pruhoniciana, results of a crossbreeding of M. tripetala MTR 1531 with M. obovata MOB 1511. The identification of neolignans was performed by HRMS after a reversed-phase high-performance liquid chromatography (RP-HPLC) fractionation of an extract from M. tripetala MTR 1531. The highest concentrations of neolignans were found in the flowers, most often in their reproductive parts, and obovatol was the most abundant in every tested plant. The highest concentrations of neolignans were detected in parent plants, and lower concentrations in hybrid magnolias. Flower extracts from the parent plants M. tripetala MTR 1531 and M. obovata MOB 1511, flower extracts from the hybrid plants Magnolia × pruhoniciana MPR 0271, MPR 0151, and MPR 1531, and leaf extract from the hybrid plant Magnolia × pruhoniciana MPR 0271 inhibited growth of Staphylococcus aureus.

Characterization of Biologically Active Substances from Calendula officinalis.

BACKGROUND: The aim of this work was to compare water and organic extracts, infusions and tinctures from flowers and leaves of Calendula officinalis in terms of their biological activity and composition. The purpose of work was investigation whether the leaves and stems are really the waste or they contain interesting substances which could be utilized. Antimicrobial, antifungal, antioxidant and anti-inflammatory activities were studied. Then, the ability to inhibit collagenase was studied as well. Cytotoxicity was tested for all the samples on mammalian cell lines. METHODS: To determine the composition of extracts, infusions and tinctures phytochemical analysis (the set of colour reactions for the detection of groups of biologically active compounds) was carried out and showed that samples from flowers and leaves contain the same groups of biologically active substances (proteins and amino acids, reducing sugars, flavonoids, saponins, phenolics, terpenoids, steroids, glycosides). The antimicrobial activity of tested samples was proved, where the most sensitive bacterium was Micrococcus luteus and the most sensitive yeast was Geotrichum candidum. RESULTS: The study of anti-collagenase activity has shown that the enzymatic reaction of collagenase was affected by all tested samples and their effect was concentration dependent. Cytotoxicity of water and methanol extracts at cell lines HEK 293T and HepG2 was observed. CONCLUSION: Cells HepG2 were more sensitive than cells HEK 293T. Using cell line RAW 264.7, antiinflammatory activity of all samples was observed. Tincture of leaves was the most effective.

Antimicrobial activity of crude extracts prepared from fungal mycelia

Objective: To evaluate the in vitro antimicrobial property of three different partitioned extracts (petroleum ether, ethanol and water) prepared from some fungal mycelia. Methods: Seven fungal mycelia were prepared, initially extracted with acidified ethanol (0.2 mol/L HCl in 80%ethanol), yielding the raw crude extracts. The obtained extracts were then further partitioned with petroleum ether (F1), ethanol (F2) and water (F3). All the fractions were tested for antimicrobial activity using the disc diffusion assay. Results: Our data showed that all the fractions could inhibit the testing bacteria. However, the inhibitory activity was found to be dependent on (i) the fungal strains used;(ii) the solvent extracted; and (iii) the testing bacteria assayed. In general, the ethanolic extracts (F2) derived from all fungi displayed highest inhibitory activity against the testing bacteria except for Chaetomium sp. Conclusions: The findings of the present study concluded that the extracts prepared from the fungal mycelia had the bioactive compounds with antibacterial property. This study is a pioneering work and further study should be carried out for development of the new drug leads.

Effect of chain elongation on biological properties of the toxin paralysin ß-alanyl-tyrosine.

In hemolymph of insect species, compounds with remarkable properties for pharmaceutical industry are present. At the first line, there were found compounds of low molecular mass, less than 1 kDa. One of such compounds, ß-alanyl-tyrosine (252 Da), was isolated from larval hemolymph of some species of holometabolous insects (e.g. Neobellieria bullata). Its paralytic activity and antimicrobial properties were described until now. In this study, we present the effect of elongation of ß-alanyl-tyrosine by repeating of this motive on the biological and physical properties of prepared analogues. For assessment of antimicrobial properties of these new compounds strains of Gram-positive, Gram-negative bacteria and fungi were used, we also followed the haemolytic activity and toxic effect on human cell culture HepG2. On the base of ECD spectroscopy measurement, subsequent molecular modelling and known secondary structure of original ß-alanyl-tyrosine dipeptide, the secondary structures of repeating sequences of ß-AY were specified. The repeating structures of ß-alanyl-tyrosine show increase in antimicrobial activity; for Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa, minimal inhibitory concentration was decreased from 30 to 15 mM for 2xß-AY, 0.4 mM for 4xß-AY and 0.25 mM for 6xß-AY.