Assessment of the allelochemical activity and biochemical profile of different phenotypes of picocyanobacteria from the genus synechococcus

Organisms belonging to Synechococcus sp. genera are observed in all freshwater, brackish, and marine waters of the world. They play a relevant role in these ecosystems, since they are one of the main primary producers, especially in open ocean. Eventually, they form mass blooms in coastal areas, which are potentially dangerous for the functioning of marine ecosystems. Allelopathy could be an important factor promoting the proliferation of these organisms. According to the authors’ best knowledge, there is no information on the allelopathic activity and allelopathic compounds exhibited by different Synechococcus sp. phenotypes. Therefore, the research conducted here aimed to study the bioactivity of compounds produced by three phenotypes of Synechococcus sp. by studying their influence on the growth, chlorophyll fluorescence, and photosynthetic pigments of eighteen cyanobacteria and microalgae species. We demonstrated that three different Synechococcus sp. phenotypes, including a phycocyanin (PC)-rich strain (Type 1; green strain) and phycoerythrin (PE)-rich strains containing phycoerythrobilin (PEB) and phycocyanobilin (PCB) (Type 2; red strain and Type 3a; brown strain), had a significant allelopathic effect on the selected species of cyanobacteria, diatoms, and green algae. For all green algae, a decrease in cell abundance under the influence of phenotypes of donor cyanobacteria was shown, whereas, among some target cyanobacteria and diatom species, the cell-free filtrate was observed to have a stimulatory effect. Our estimates of the stress on photosystem II (Fv/Fm) showed a similar pattern, although for some diatoms, there was an effect of stress on photosynthesis, while a stimulatory effect on growth was also displayed. The pigment content was affected by allelopathy in most cases, particularly for chlorophyll a, whilst it was a bit less significant for carotenoids. Our results showed that Synechococcus sp. Type 3a had the strongest effect on target species, while Synechococcus sp. Type 1 had the weakest allelopathic effect. Furthermore, GC-MS analysis produced different biochemical profiles for the Synechococcus strains. For every phenotype, the most abundant compound was different, with oxime-, methoxy-phenyl- being the most abundant substance for Synechococcus Type 1, eicosane for Synechococcus Type 2, and silanediol for Synechococcus Type 3aThis research was founded by BMN grant number 539-O140-B416-20, FCT Projects UIDB/04423/2020and UIDP/04423/2020

Extracellular vimentin is sufficient to promote cell attachment, spreading, and motility by a mechanism involving N-acetyl glucosamine-containing structures

Vimentin intermediate !laments form part of the cytoskeleton of mesenchymal cells, but under pathological conditions often associatedwith in ammation, vimentin !laments depolymerize as the result of phosphorylation or citrullination, and vimentin oligomers are secreted or released into the extracellular environment. In the extracellular space, vimentin can bind surfaces of cells and the extracellular matrix, and the interaction between extracellular vimentin and cells can trigger changes in cellular functions, such as activation of !broblasts to a !brotic phenotype. The mechanism by which extracellular vimentin binds external cell membranes and whether vimentin alone can act as an adhesive anchor for cells is largely uncharacterized. Here, we show that various cell types (normal and vimentin null !broblasts, mesenchymal stem cells, and A549 lung carcinoma cells) attach to and spread on polyacrylamide hydrogel substrates covalently linked to vimentin. Using traction force microscopy and spheroid expansion assays, we characterize how different cell types respond to extracellular vimentin. Cell attachment to and spreading on vimentin-coated surfaces is inhibited by hyaluronic acid degrading enzymes, hyaluronic acid synthase inhibitors, soluble heparin or N-acetyl glucosamine, all of which are treatments that have little or no effect on the same cell types binding to collagen-coated hydrogels. These studies highlight the effectiveness of substratebound vimentin as a ligand for cells and suggest that carbohydrate structures, including the glycocalyx and glycosylated cell surface proteins that contain N-acetyl glucosamine, form a novel class of adhesion receptors for extracellular vimentin that can either directly support cell adhesion to a substrate or !ne-tune the glycocalyx adhesive properties

Magnetic nanoparticles as separators of nucleic acids

Separacja i oczyszczanie kwasów nukleinowych jest podstawowym etapem większości procedur i technik stosowanych w biologii molekularnej. Istnieje wiele metod izolacji DNA, w wyniku których otrzymuje się DNA biologicznie aktywny, chemicznie stabilny oraz wolny od RNA i białek. Nanocząstki magnetyczne z rdzeniem Fe3O4 pokryte otoczką aminosilanową, zostały zsyntetyzowane celem oceny ich przydatności w zakresie separacji makromolekuł (DNA). Zastosowanie nanocząstek do izolacji kwasów nukleinowych może stanowić podstawę do ustalenia nowych standardów diagnostycznych w biologii molekularnej.The separation and purification of nucleic acids is an essential step in most of the procedures and techniques used in molecular biology. There are many procedures describing the method of DNA isolation, which result in obtaining a RNA-free DNA, proteins and other compounds that may interfere in subsequent analyzes. Magnetic nanoparticles coated by aminosilanes, were synthesized in order to assess their suitability for the separation of macromolecules (DNA). The use of nanoparticles for the isolation of nucleic acids may provide the basis for setting new standards for diagnostic molecular biology

New acetylacetone-polymer modified nanoparticles as magnetically separable complexing agents

In this paper, we present two methods of synthesis of new bifunctional polymeric nanohybrids and their full characterization. These nanohybrids consist of a magnetic nanoparticle core and polymeric shell which possess the ability to complex metal ions and organic compounds. Synthesized materials exhibit superparamagnetic properties and can thus be easily separated from complex mixtures by using an external magnetic field (facile separation, purification and recyclability). Herein, the syntheses of three bifunctional monomers are presented. Each of them was used to prepare the homopolymeric shell and two types of copolymeric shells (using styrene as a comonomer) around the magnetite nanoparticles. A surface initiated RAFT/MADIX polymerization technique was employed to prepare polymeric shells. Afterwards, post-modification of azide functionalized polymeric shells using the Huisgen “click” reaction was performed. Finally, twelve types of nanohybrids were prepared and their physicochemical properties were investigated. Additionally, the ability of nanohybrids to complex lanthanides and spectroscopic properties of obtained materials were studied

Inhibition of inflammatory response in human keratinocytes by magnetic nanoparticles functionalized with PBP10 peptide derived from the PIP2-binding site of human plasma gelsolin

Abstract Background Human plasma gelsolin (pGSN) is a multifunctional actin-binding protein involved in a variety of biological processes, including neutralization of pro-inflammatory molecules such as lipopolysaccharide (LPS) and lipoteichoic acid (LTA) and modulation of host inflammatory response. It was found that PBP10, a synthetic rhodamine B-conjugated peptide, based on the phosphoinositide-binding site of pGSN, exerts bactericidal activity against Gram-positive and Gram-negative bacteria, interacts specifically with LPS and LTA, and limits microbial-induced inflammatory effects. The therapeutic efficiency of PBP10 when immobilized on the surface of iron oxide-based magnetic nanoparticles was not evaluated, to date. Results Using the human keratinocyte cell line HaCaT stimulated by bacterially-derived LPS and LTA as an in vitro model of bacterial infection, we examined the anti-inflammatory effects of nanosystems consisting of iron oxide-based magnetic nanoparticles with aminosilane (MNP@NH2) or gold shells (MNP@Au) functionalized by a set of peptides, derived from the phosphatidylinositol 4,5-bisphosphate (PIP2)-binding site of the human plasma protein gelsolin, which also binds LPS and LTA. Our results indicate that these nanosystems can kill both Gram-positive and Gram-negative bacteria and limit the production of inflammatory mediators, including nitric oxide (NO), reactive oxygen species (ROS), and interleukin-8 (IL-8) in the response to heat-killed microbes or extracted bacterial cell wall components. The nanoparticles possess the potential to improve therapeutic efficacy and are characterized by lower toxicity and improved hemocompatibility when compared to free peptides. Atomic force microscopy (AFM) showed that these PBP10-based nanosystems prevented changes in nanomechanical properties of cells that were otherwise stimulated by LPS. Conclusions Neutralization of endotoxemia-mediated cellular effects by gelsolin-derived peptides and PBP10-containing nanosystems might be considered as potent therapeutic agents in the improved therapy of bacterial infections and microbial-induced inflammation

Recombinant Human Plasma Gelsolin Stimulates Phagocytosis while Diminishing Excessive Inflammatory Responses in Mice with Pseudomonas aeruginosa Sepsis

Plasma gelsolin (pGSN) is a highly conserved abundant circulating protein, characterized by diverse immunomodulatory activities including macrophage activation and the ability to neutralize pro-inflammatory molecules produced by the host and pathogen. Using a murine model of Gram-negative sepsis initiated by the peritoneal instillation of Pseudomonas aeruginosa Xen 5, we observed a decrease in the tissue uptake of IRDye®800CW 2-deoxyglucose, an indicator of inflammation, and a decrease in bacterial growth from ascitic fluid in mice treated with intravenous recombinant human plasma gelsolin (pGSN) compared to the control vehicle. Pretreatment of the murine macrophage line RAW264.7 with pGSN, followed by addition of Pseudomonas aeruginosa Xen 5, resulted in a dose-dependent increase in the proportion of macrophages with internalized bacteria. This increased uptake was less pronounced when cells were pretreated with pGSN and then centrifuged to remove unbound pGSN before addition of bacteria to macrophages. These observations suggest that recombinant plasma gelsolin can modulate the inflammatory response while at the same time augmenting host antibacterial activity

Solid State Characterization of Bridged Steroidal Molecular Rotors: Effect of the Rotator Fluorination on Their Crystallization

We describe the synthesis and crystallization of two macrocyclic steroidal compounds labeled (<i>Z</i>)-<b>1F</b>₂ and (<i>E</i>)-<b>1F</b>₂, envisioned to work as molecular rotors with 1,4-diethynyl-2,3-difluorophenylene rotators. The introduction of the fluorine atoms rendered different crystal arrays that were fully characterized by X-ray diffraction, solid state ¹³C NMR, and calorimetric experiments. In both isomers, the central molecular fragments point the <i>o</i>-fluorine atoms toward their cavity, highlighting the preferred orientation in the solid state. By analyzing the crystal array, it can be seen that while the fluorinated <i>Z</i> isomer is isomorphic to its non-fluorinated analogue, the <i>E</i> isomer shows significant structural variations in an unanticipated crystal array with two molecules per asymmetric unit (<i>Z</i>′ = 2)