DSPE

Strains ofErwinia tracheiphila,causal agent of bacterial wilt of cucurbits, are divided into distinct clades.Et-meloclade strains wiltCucumisspp. but notCucurbitaspp., thus exhibiting host specificity, whereasEt-C1clade strains wiltCucurbitaspp. more rapidly thanCucumis melo, thus exhibiting a host preference. This study investigated the contribution of the effector proteins Eop1 and DspE toE. tracheiphilapathogenicity and host adaptation. Loss ofeop1did not enableEt-melostrains to infect squash (Cucurbita pepo) or anEt-C1strain to induce a more rapid wilt of muskmelon (Cucumis melo), indicating that Eop1 did not function in host specificity or preference as in the related pathogenE. amylovora.However, overexpression ofeop1fromEt-melostrain MDCuke but not fromEt-C1strain BHKY increased the virulence of a BHKYeop1deletion mutant on muskmelon, demonstrating that the Eop1 variants in the two clades are distinct in their virulence functions. Loss ofdspEfromEt-melostrains reduced but did not eliminate virulence on hosts muskmelon and cucumber, whereas loss ofdspEfrom anEt-C1strain eliminated pathogenicity on hosts squash, muskmelon, and cucumber. Thus, the centrality of DspE to virulence differs in the two clades.Et-melomutants lacking the chaperone DspF exhibited similar virulence to mutants lacking DspE, indicating that DspF is the sole chaperone for DspE inE. tracheiphila, unlike inE. amylovora. Collectively, these results provide the first functional evaluation of effectors inE. tracheiphilaand demonstrate clade-specific differences in the roles of Eop1 and DspE.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

Fruits and vegetables constitute a major type of food consumed daily apart from whole grains. Unfortunately, the residual deposits of pesticides in these products are becoming a major health concern for human consumption. Consequently, the outcome of the long-term accumulation of pesticide residues has posed many health issues to both humans and animals in the environment. However, the residues have previously been determined using conventionally known techniques, which include liquid-liquid extraction, solid-phase extraction (SPE) and the recently used liquid-phase microextraction techniques. Despite the positive technological effects of these methods, their limitations include; time-consuming, operational difficulty, use of toxic organic solvents, low selective property and expensive extraction setups, with shorter lifespan of instrumental performances. Thus, the potential and maximum use of these methods for pesticides residue determination has resulted in the urgent need for better techniques that will overcome the highlighted drawbacks. Alternatively, attention has been drawn recently towards the use of quick, easy, cheap, effective, rugged and safe technique (QuEChERS) coupled with dispersive solid-phase extraction (dSPE) to overcome the setback challenges experienced by the previous technologies. Conclusively, the reviewed QuEChERS-dSPE techniques and the recent cleanup modifications justifiably prove to be reliable for routine determination and monitoring the concentration levels of pesticide residues using advanced instruments such as high-performance liquid chromatography, liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry.

Causing more and more deaths, stroke has been a leading cause of death worldwide. However, success in clinical stroke trials has remained elusive. N-oleoylethanolamine (OEA) was an endogenous highly hydrophobic molecule with outstanding neuroprotective effect. In this article, hydrogen bonds were successfully formed between OEA and soybean phosphatidylcholine (SPC). The synthetic OEA-SPC complex and DSPE-PEG were self-assembled into liposomes (OEA NPs), with OEA-SPC loaded in the core and PEG formed a hydrophilic shell. Hence, highly hydrophobic OEA was loaded into liposomes as amorphous state with a drug loading of 8.21 ± 0.18 wt%. With fairly uniform size and well-distributed character, the OEA NPs were systemically assessed as an intravenous formulation for stroke therapy. The results indicated that the administration of OEA NPs could significantly improve the survival rate and the Garcia score of the MCAO rats compared with free OEA. The TTC-stained brain slices declared that the cerebral infarct volume and the edema degree induced by MCAO could be decreased to an extremely low levelviathe administration of OEA NPs. The Morris water maze (MWM) test suggested that the spatial learning and memory of the MCAO rats could also be ameliorated by OEA NPs. The immunofluorescence assay stated that the apoptosis of the neurons and the inflammation within the brain were greatly inhibited. The results suggest that the OEA NPs have a great chance to develop OEA as a potential anti-stroke formulation for clinic application.

Previously, we reported the formation of 100-200 nm disk- and tube-like nanoparticles by hydration ofL-ascorbyl 2,6-dipalmitate (ASC-DP) and distearoylphosphatidylethanolamine polyethylene glycol 2000 (DSPE-PEG) films prepared at an initial molar ratio of 2:1. This study investigated the feasibility of nanoparticle formation with higher ASC-DP loading. Although particle size distribution determined by dynamic light scattering showed a multimodal pattern including micro-sized particles at a molar ratio of 3:1, the mean particle size gradually decreased with a further increased molar ratio. Homogeneous ca. 240 nm nanoparticles with a unimodal size distribution were obtained at a molar ratio of 10:1. FE-TEM showed that the nanoparticles at a molar ratio of 10:1 were rod-shaped with a diameter of ca. 100 nm and a length of ca. 300 nm. After centrifugation, X-ray analysis of the nanoparticle precipitates showed that these rod-like nanoparticles were composed of a series of lamellar structures with 3.7 nm repeated units. The molar ratio of ASC-DP/DSPE-PEG in the nanoparticle precipitates determined by1H NMR measurements was 68.8:1. The rod-like nanoparticles should be composed of a core-shell structure, where a small amount of DSPE-PEG covers the lamellar structure of ASC-DP. Further increase in the ASC-DP/DSPE-PEG molar ratio over 33:1 no longer provided nanoparticles. Hence, to prepare a stable ASC-DP nanoparticle suspension, it is necessary to prepare ASC-DP/DSPE-PEG films containing at least 3 mol% DSPE-PEG.

Nowadays, finding a novel, effective, biocompatible, and minimally invasive cancer treatment is of great importance. One of the most promising research fields is the development of biocompatible photothermal nanocarriers. PTT (photothermal therapy) with an NIR (near-infrared) wavelength range (700-2000 nm) would cause cell death by increasing intercellular and intracellular temperature. PTT could also be helpful to overcome drug resistance during cancer treatments. In this study, an amine derivative of phospholipid poly ethylene glycol (DSPE-PEG (5000) amine) was conjugated with SWCNTs (single-walled carbon nanotubes) to reduce their intrinsic toxicity. Toxicity studies were performed on lung, liver, and ovarian cancer cell lines that were reported to show some degree of drug resistance to cisplatin. Toxicity results suggested that DSPE-PEG (5000) amine SWCNTs might be biocompatible photothermal nanocarriers in PTT. Therefore, our next step was to investigate the effect of DSPE-PEG (5000) amine SWCNT concentration, cell treatment time, and laser fluence on the apoptosis/necrosis of SKOV3 cells post-NIR exposure by RSM and experimental design software. It was concluded that photothermal efficacy and total apoptosis would be dose-dependent in terms of DSPE-PEG (5000) amine SWCNT concentration and fluence. Optimal solutions which showed the highest apoptosis and lowest necrosis were then achieved.

Uniform monodispersed nitrogen-doped carbon spheres have been emerging as an exciting platform for multipurpose medical applications like photothermal therapy and photoacoustic imaging and as carriers for aromatic anticancer drugs. However, synthesis of uniform N-doped mesoporous carbon of size less than 100 nm with reasonable photothermal and photodynamic activities is a challenging task. In this connection, the present paper reports synthesis of nitrogen-doped mesoporous carbon spheres (NMCSs) from five different copolymers of pyrrole and substituted aniline (-H,o-NH2,m-NH2,p-NH2, andm-NO2) using a soft template approach. It has been found that NMCSs synthesized from poly(pyrrole-co-m-nitroaniline) show uniform mesoporous particles of size 80 nm, a photothermal conversion efficiency η of 52.7%, and an average1O2quantum yield of 20% under exposure of a 980 nm NIR laser. With a high η of 52%, a multifunctional nanodrug has been formulated by loading 5-Fu in NMCS. The overall drug-loaded NMC was encapsulated by thermosensitive DSPE-PEG to improve translocation of the particle in the cell and thermosensitive drug release. A reliable release of anticancer drug 5-Fu (78%) has been achieved in 50 h in lysosomal conditions under 980 nm laser exposure. This NMC-5-Fu-DSPE-PEG nanodrug produces reactive oxygen species and enhances the therapeutic effect in comparison with free drug under an NIR laser as verified in B16F0 melanoma cells.

Corannulene (Cor) is a polycyclic aromatic hydrocarbon (PHA) whose molecular structure is three dimensional with a unique bowl-like structure and surface charge. Perylene (Per) is similar to corannulene, with 20π electrons in its fragrance system, but it is a planar structure. Although scientists in various fields have been extensively investigating corannulene, the toxicological evaluation on organisms and its possible mechanisms remain unclear. Our objective is to investigate the toxic effects of corannulene and perylene on ovaries and oocytes. First, corannulene and perylene were wrapped with 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethyleneglycol)] (mPEG-DSPE) to form mPEG-DSPE/corannulene nanoparticles (mP-D/CoNps) and mPEG-DSPE/perylene nanoparticles (mP-D/PeNps), which enhanced their water solubility and biocompatibility. Then, the toxic effects of mP-D/CoNps or mP-D/PeNps on the quality of mouse oocytes and their possible mechanisms were studiedin vivo. Our results indicated that mP-D/CoNps or mP-D/PeNps affected the first polar body extrusion of oocytes, increased the number of primordial follicles in the ovary, altered mitochondrial membrane potentials, induced oxidative stress and led to autophagy and apoptosis.

1, 2-Distearoyl-sn-glycero-3-phosphoethanolamine-Poly(ethylene glycol) (DSPE- PEG) is a widely used phospholipids-polymer conjugate in drug delivery applications. It is a biocompatible, biodegradable and amphiphilic material which can also be functionalized with various biomolecules for specific functions. With the emerging interest in use of nanocarriers for therapeutic drug delivery and imaging DSPE-PEG has become a very useful material for the formulation of these nanocarriers for achieving prolonged blood circulation time, improved stability and enhanced encapsulation efficiency. This review will focus on the relationships between the structure of DSPEPEG and its noticeable effects on these nanocarriers' properties, and the recent progress on the development of DSPE-PEG and its derivatives in delivery systems.

In order to improve stability of a peptide marine drug lead, α-conotoxin TxID, we synthesized and modified TxID at the N-terminal with DSPE-PEG-NHS by a nucleophilic substitution reaction to prepare the DSPE-PEG-TxID for the first time. The reaction conditions, including solvent, ratio, pH, and reaction time, were optimized systematically and the optimal one was reacted in dimethyl formamide at pH 8.2 with triethylamine at room temperature for 120 h. The in vitro stabilities in serum, simulated gastric juice, and intestinal fluid were tested, and improved dramatically compared with TxID. The PEG-modified peptide was functionally tested on α3β4 nicotinic acetylcholine receptor (nAChR) heterologously expressed inXenopus laevisoocytes. The DSPE-PEG-TxID showed an obvious inhibition effect on α3β4 nAChR. All in all, the PEG modification of TxID was improved in stability, resistance to enzymatic degradation, and may prolong the half-life in vivo, which may pave the way for the future application in smoking cessation and drug rehabilitation, as well as small cell lung cancer.

Objective:This study aims to investigate the potential of DSPE-PEG polymers (DSPE-PEG-OH and DSPE-PEG-SH) on improving absorption of poorly absorbable macromoleculesviaintrapulmonary administration and underlying mechanism.Methods:In situpulmonary absorption experiments were performed to investigate the absorption of model compounds after intrapulmonary administration to rats. The local membrane damage induced by these DSPE-PEG polymers were evaluated based on morphological observation of lung tissues and measurement of biological toxic markers in bronchoalveolar lavage fluid (BALF) postintrapulmonary delivery of DSPE-PEG polymers to rats. The underlying enhancement mechanism of these polymers was explored by investigating their effects on the pulmonary membrane fluidity and gene expression of tight junction associated proteins with fluorescence polarization and western blotting, respectively.Results:Intrapulmonary delivery of these DSPE-PEG polymers significantly enhanced absorptions of poorly absorbed model drugs and did not induce serious damage to the pulmonary membranes of rats. Mechanistic studies demonstrated unaffected pulmonary membrane fluidity and up-regulated expression levels of tight junction-associated proteins by DSPE-PEG polymers, thus indicating that paracellular pathways might be included in the underlying mechanisms by which DSPE-PEG polymers exerted their enhancing actions on drug absorption.Conclusions:These findings suggested that these DSPE-PEG polymers are potential for promoting absorptions of poorly absorbable macromolecules with no evidence of damage to the local pulmonary membranes of rats.Novelty statementIn this study, DSPE-PEG-OH and DSPE-PEG-SH polymers, two DSPE-PEG2000 conjugates with different terminal groups demonstrated significant promoting effects on the absorption of poorly absorbed macromolecular drugs after intrapulmonary delivery to rats, and did not induce serious damage to the pulmonary membranes of rats. These DSPE-PEG polymers could statistically downregulate expression levels of tight junction-associated proteins (ZO-1 and occludin), indicating the underlying mechanism by which these polymers exerted their absorption enhancing actions through pulmonary epithelial paracellular pathways. Thus, this study exhibited prospective potential of these DSPE-PEG polymers in developing into dosage forms with the aim to improve the poor bioavailability of some poorly absorbed macromolecular drugs.