Self-Assembly of Cholesterol-Doxorubicin and TPGS into Prodrug-Based Nanoparticles with Enhanced Cellular Uptake and Lysosome-Dependent Pathway in Breast Cancer Cells

Developing new easy-to-prepare functional drug delivery nanosystems with good storage stability, low hemotoxicity, as well as controllable drug delivery property, has attracted great attention in recent years. In this work, a cholesterol-based prodrug nanodelivery system is prepared by self-assembly of cholesterol-doxorubicin prodrug conjugates (Chol-Dox) and tocopherol polyethylene glycol succinate (TPGS) using thin-film hydration method. The Chol-Dox/TPGS assemblies (molar ratio 2:1, 1:1, and 1:2) are able to form nanoparticles with average hydrodynamic diameter of ≈140–214 nm, surface zeta potentials of ≈−24.2–−0.3 mV, and remarkable solution stability in 0.1 m PBS, 16 days). The Chol-Dox/TPGS assemblies show low hemotoxicity and different cytotoxicity profiles in breast cancer cells (MCF-7 and MDA-MB-231), which are largely dependent on the molar ratio of Chol-Dox and TPGS. The Chol-Dox/TPGS assemblies tend to enter into MCF-7 and MDA-MB-231 cells through non-Clathrin-mediated multiple endocytosis and lysosome-dependent uptake pathways, moreover, these nanoassemblies demonstrate lysosome-dependent intracellular localization, which is different from that of free DOX (nuclear localization). The results demonstrate that the Chol-Dox/TPGS assemblies are promising cholesterol-based prodrug nanomaterials for breast cancer chemotherapy. Practical Applications: This work demonstrates a lipid prodrug-based nanotherapeutic system. Herein the Chol-Dox/TPGS nanoassemblies could serve as promising and controllable cholesterol-based prodrug nanomaterials/nano-formulations for potential breast cancer chemotherapy.     

Effects of Charge and Charge Distribution on the Cellular Uptake of Multivalent Arginine‐Containing Peptide–Polymer Conjugates

Copolymers of N‐(2‐hydroxypropyl)methacrylamide (HPMA) and N‐methacryloyl‐β‐alaninyl‐S‐benzyl thioester were prepared by employing free radical or RAFT conditions and denominated as “NCL polymers”. The copolymer with a polydispersity index of 1.2–1.3 was used for the direct conjugation of unprotected peptides and peptide mixtures bearing differentially loaded side chains by native chemical ligation reactions conducted in aqueous buffer. Uptake into human HeLa cells was correlated with the overall surface charge and the ζ potentials of the peptide–polymer conjugates. Most notable were the differential effects found for various multivalent peptide–polymer conjugates containing arginine residues. Although positive ζ potentials were required for cellular uptake of the peptide–polymer conjugates, this sole charge effect was strongly dominated by the effect exerted by the relative distribution of arginine residues. Polymers conjugated with nona‐arginine peptides were over‐proportionally taken up, relative to their surface charge, compared to polymers with random distribution of single arginine residues. In view of these findings, peptide–polymer compositions suitable for efficient cellular uptake with negligible toxicity at polymer concentrations relevant for intracellular functional studies were determined.     

离子选择性电极法对不同无机代磷助剂钙交换速率的研究

用离子选择性电极法对A型分子筛、小晶粒A型分子筛、高铝P型分子筛 (MAP)、Na2 SiO3 ·9H2 O、层状二硅酸钠等不同无机代磷助剂的钙交换速率进行测定 ,并将它们与三聚磷酸钠 (STPP)进行比较 ,结果发现STPP不论在钙交换速率上还是钙交换深度上都优于其他助剂 ;Na2 SiO3 ·9H2 O表现出较快的钙交换速率 ,但钙交换深度不够 ;分子筛中小晶粒A表现出较快的钙交换速度 ,而MAP型分子筛则相对较慢 ,其顺序为MAP 相似文献   

Effects of Different Gluten Proteins on Starch’s Structural and Physicochemical Properties during Heating and Their Molecular Interactions

Starch–gluten interactions are affected by biopolymer type and processing. However, the differentiation mechanisms for gluten–starch interactions during heating have not been illuminated. The effects of glutens from two different wheat flours (a weak-gluten (Yangmai 22, Y22) and a medium-strong gluten (Yangmai 16, Y16)) on starch’s (S) structural and physicochemical properties during heating and their molecular interactions were investigated in this study. The results showed that gluten hindered the gelatinization and swelling of starch during heating when temperature was below 75 °C, due to competitive hydration and physical barriers of glutens, especially in Y22. Thus, over-heating caused the long-range molecular order and amylopectin branches of starch to be better preserved in the Y22-starch mixture (Y22-S) than in the Y16-starch mixture (Y16-S). Meanwhile, the starch’s degradation pattern during heating in turn influenced the polymerization of both glutens. During heating, residual amylopectin branching points restricted the aggregation and cross-linking of gluten proteins due to steric hindrance. More intense interaction between Y16 and starch during heating mitigated the steric hindrance in starch–gluten networks, which was due to more residual short-range ordered starch and hydrogen bonds involved in the formation of starch–gluten networks in Y16-S during heating.     

Molecular Mechanisms for the Regulation of Insulin-Stimulated Glucose Uptake by Small Guanosine Triphosphatases in Skeletal Muscle and Adipocytes

Insulin is a hormone that regulates the blood glucose level by stimulating various physiological responses in its target tissues. In skeletal muscle and adipose tissue, insulin promotes membrane trafficking of the glucose transporter GLUT4 from GLUT4 storage vesicles to the plasma membrane, thereby facilitating the uptake of glucose from the circulation. Detailed mechanisms underlying insulin-dependent intracellular signal transduction for glucose uptake remain largely unknown. In this article, I give an overview on the recently identified signaling network involving Rab, Ras, and Rho family small guanosine triphosphatases (GTPases) that regulates glucose uptake in insulin-responsive tissues. In particular, the regulatory mechanisms for these small GTPases and the cross-talk between protein kinase and small GTPase cascades are highlighted.     

Activity of Novel Ultrashort Cyclic Lipopeptides against Biofilm of Candida albicans Isolated from VVC in the Ex Vivo Animal Vaginal Model and BioFlux Biofilm Model—A Pilot Study

In recent years, clinicians and doctors have become increasingly interested in fungal infections, including those affecting the mucous membranes. Vulvovaginal candidiasis (VVC) is no exception. The etiology of this infection remains unexplained to this day, as well as the role and significance of asymptomatic vaginal Candida colonization. There are also indications that in the case of VVC, standard methods of determining drug susceptibility to antifungal drugs may not have a real impact on their clinical effectiveness—which would explain, among other things, treatment failures and relapse rates. The aim of the study was to verify the promising results obtained previously in vitro using standard methods, in a newly developed ex vivo model, using tissue fragments of the mouse vagina. The main goal of the study was to determine whether the selected ultrashort cyclic lipopeptides (USCLs) and their combinations with fluconazole at specific concentrations are equally effective against Candida forming a biofilm directly on the surface of the vaginal epithelium. In addition, the verification was also performed with the use of another model for the study of microorganisms (biofilms) in vitro—the BioFlux system, under microfluidic conditions. The obtained results indicate the ineffectiveness of the tested substances ex vivo at concentrations eradicating biofilm in vitro. Nevertheless, the relatively most favorable and promising results were still obtained in the case of combination therapy—a combination of low concentrations of lipopeptides (mainly linear analogs) with mycostatic fluconazole. Additionally, using BioFlux, it was not possible to confirm the previously obtained results. However, an inhibiting effect of the tested lipopeptides on the development of biofilm under microfluidic conditions was demonstrated. There is an incompatibility between the classic in vitro methods, the newer BioFlux method of biofilm testing, offering many advantages postulated elsewhere, and the ex vivo method. This incompatibility is another argument for the need, on the one hand, to intensify research on the pathomechanism of VVC, and, on the other hand, to verify and maybe modify the standard methods used in the determination of Candida susceptibility.     

Probing the Structural Properties of DNA/RNA Grooves with Sterically Restricted Phosphonium Dyes: Screening of Dye Cytotoxicity and Uptake

To explore in greater detail the recently reported rare kinetic differentiation between homo‐polymeric and alternating AT‐DNA sequences by using sterically restricted phosphonium dyes that form dimers within the DNA minor groove, new analogues were prepared in which the quinolone phosphonium moiety was kept constant, while the size and hydrogen bonding properties of the rest of the molecule were varied. Structure–activity relationship studies revealed that a slight increase in length by an additional methylene unit results in loss of kinetic AT selectivity, but yielded an AT‐selective fluorescence response. These DNA/RNA‐groove‐bound dyes combine very low cytotoxicity with efficient cellular uptake and intriguingly specific fluorescent marking of mitochondria. In contrast to longer analogues, a decrease in length (by methylene unit removal) and rearrangement of positive charge resulted in dyes that had switched to the intercalative binding mode to GC DNA/dsRNA but that still form dimers in the minor groove of AT sequences, consequently yielding a significantly different chiro‐optical response. The latter dyes also revealed strongly selective antiproliferative activity toward HeLa cancer cells.     

The Influence of Pre‐Electrospinning Plasma Treatment on Physicochemical Characteristics of PLA Nanofibers

Morphology, crystallinity, thermal, and mechanical properties of nanofibrous mats are known to highly affect the behavior of these materials in desired applications. In this study, multiple characteristics of poly(lactic acid) (PLA) nanofibrous mats prepared from plasma‐treated pre‐electrospinning solutions are studied as a function of various plasma operational parameters. X‐ray diffraction, differential scanning calorimetry, thermogravimetric analysis, X‐ray photoelectron spectroscopy, scanning electron microscopy, and tensile tests are performed. In addition, the pristine and plasma‐treated PLA solutions are examined with size exclusion chromatography to study the effect of the conducted pre‐electrospinning plasma treatments (PEPT) on the molecular weight of PLA. Aging analysis of the pristine and plasma‐treated solutions is also performed by evaluating the viscosity, conductivity, surface tension, and pH during an aging period of 10 days. To investigate if the results are only affected by the plasma treatment or also affected by the electrospinning, pristine and plasma‐treated PLA cast layers are also analyzed. The results reveal that PEPT preserved the surface chemical composition of the nanofibers and the molecular weight distribution of PLA, while morphology and mechanical properties of the nanofibers are considerably enhanced. Moreover, plasma‐treated polymer solutions resulted in the formation of nicely elongated nanofibers up to 4 days after plasma treatment.     

Modeling of Neurodegenerative Diseases: ‘Step by Step’ and ‘Network’ Organization of the Complexes of Model Systems

Neurodegenerative diseases have acquired the status of one of the leading causes of death in developed countries, which requires creating new model systems capable of accurately reproducing the mechanisms underlying these pathologies. Here we analyzed modern model systems and their contribution to the solution of unexplored manifestations of neuropathological processes. Each model has unique properties that make it the optimal tool for modeling certain aspects of neurodegenerative disorders. We concluded that to optimize research, it is necessary to combine models into complexes that include organisms and artificial systems of different organizational levels. Such complexes can be organized in two ways. The first method can be described as “step by step”, where each model for studying a certain characteristic is a separate step that allows using the information obtained in the modeling process for the gradual study of increasingly complex processes in subsequent models. The second way is a ‘network’ approach. Studies are carried out with several types of models simultaneously, and experiments with each specific type are adjusted in conformity with the data obtained from other models. In our opinion, the ‘network‘ approach to combining individual model systems seems more promising for fundamental biology as well as diagnostics and therapy.     

流加培养过程中杂交瘤细胞的摄氧率与生长代谢之间的关联

摄氧率(OUR)不仅易于在线检测而且可以快速反映细胞的物质和能量代谢状况。为此,利用2 L B.Braun反应器的恒速流加培养工艺,考察了杂交瘤细胞的摄氧率与生长、代谢之间的关系。OUR与活细胞密度成良好的正相关性,但由于氧比消耗速率不是常数,所以二者不呈线性关系,从而利用OUR只能估测,而不能准确计算细胞密度。随着葡萄糖浓度降至低水平,氧比消耗速率、ATP比生成速率下降,而氧与葡萄糖的消耗计量比、细胞对氧的消耗逐增,由氧化磷酸化生成的ATP比例上升,说明葡萄糖代谢途径逐渐从糖酵解途径迁移到三羧酸循环,被氧化程度提高,能量利用率增强。     

Grain-Boundary Characteristics and Their Influence on the Electrical Resistance of Barium Titanate Ceramics

The integral and spectral cathodoluminescence (CL) properties of grain-boundary zones in positive-temperature-coefficient-type barium titanate ceramics were investigated with respect to typical sintering parameters in the spectral range 300 to 1800 nm at room temperature. Spatially resolved CL micrographs for the wavelength range 300 to 850 nm show dark grain-boundary zones and light grain interiors. Corresponding micrographs for the infrared wavelength range 800 to 1800 nm show just the opposite CL contrast. The CL properties of the grain-boundary zone can be correlated to doubly ionized barium vacancies. Therefore, grain-boundary zones which are visible in integral CL images of both wavelength ranges represent the theoretically predicted grain-boundary zone of high barium vacancy concentrations. The width of these grain-boundary zones varies characteristically with sintering time and cooling rate. Additional measurements of the electrical conductivity of the specimens confirmed the theoretically assumed correlation between grain-boundary-zone width and electrical resistance of the samples.     

Influence of Heat Treatments on the Pore and Adsorption Characteristics of Sodium Doped Alumina Pillared Bentonite

Various amounts of Na+ ions were exchanged into alumina pillared bentonite (Al-PILB) sample, by controlling the pH of the dispersion of Al-PILB and sodium chloride solution. The Na+ doped pillared clays were calcined at elevated temperatures and adsorption of nitrogen at –196°C, cyclohexane and water at ambient temperature (21 ± 1°C) by the calcined samples were conducted. The results revealed a wide size distribution of the micropores in the pillared clay. Introduction of sodium ions converted the surface of the pore walls from hydrophobic to hydrophilic and blocks some micropores, enhancing water adsorption but reducing nitrogen and cyclohexane adsorption. Existence of Na+ ions in the pores did not improve the thermal stability of the pillared clay. Calcination at high temperatures resulted in a decrease in adsorption capacity. After calcination at 700°C, cyclohexane was inaccessible to the remaining micropores in the Na+ doped pillared clays. The adsorption behavior was clearly related to the cation content as well as the calcination temperature. These results may be useful in developing desiccants and adsorbents from pillared clays for dehumidification and adsorptive cooling applications.     

碱性染料在蔺草染色中上染率和摩擦牢度的研究

选用碱性兰染料对蔺草进行染色,探讨染液pH值、染色保温温度、染料用量、电解质的用量及染色保温时间对蔺草上染率和摩擦牢度的影响,结果表明,用碱性兰染料对蔺草进行染色时,最佳上染率和摩擦牢度的工艺条件是:染液pH值7～10,染色保温温度80℃,染色温度在70℃以下时升温速率控制在3℃/min,染色温度在70～80℃时升温速率控制在1℃/2 min,染料用量为0.5%～1%(owf),元明粉用量10 g/L,染色保温时间20 min。     

Impact of the guanidinium group on hybridization and cellular uptake of cationic oligonucleotides

The grafting of cationic groups to synthetic oligonucleotides (ONs) in order to reduce the charge repulsion between the negatively charged strands of a duplex or triplex, and consequently to increase a complex's stability, has been extensively studied. Guanidinium groups, which are highly basic and positively charged over a wide pH range, could be an efficient ON modification to enhance their affinity for nucleic acid targets and to improve cellular uptake. A straightforward post-synthesis method to convert amino functions attached to ONs (on sugar, nucleobase or backbone) into guanidinium tethers has been perfected. In comparison to amino groups, such cationic groups anchored to alpha-oligonucleotide phosphoramidate backbones play important roles in duplex stability, particularly with RNA targets. This high affinity could be explained by dual recognition resulting from Watson-Crick or Hoogsteen base pairing combined with cationic/anionic backbone recognition between strands involving H-bond formation and salt bridging. Molecular-dynamics simulations corroborate interactions between the cationic backbones of the alpha-ONs and the anionic backbones of the nucleic acid targets. Moreover, ONs with guanidinium modification increased cellular uptake relative to negatively charged ONs. The cellular localization of these new cationic phosphoramidate ONs is mainly cytoplasmic. The uptake of these ON analogues might occur through endocytosis.     

Influence of the Composition of Carbon-fiber Phenolformaldehyde Composite Materials on Their Tribological Characteristics

Abstract

Carbon-fiber phenolformaldehyde composite materials have been obtained by two technological methods—prepreg and dry mixing of components. The tribological properties of the composite materials are investigated. As such tribological characteristics are used friction factor and the intensity of wear as a criterion for the wear stability of the material. Influence of some dispersion fillers-bentonite clay, talc, kaolin and boron carbide is investigated to the tribological characteristics. The influence of loading and the speed of sliding over the friction factor and the wear hardness is determined too.

The tribological properties of the obtained composite materials help them join the best materials working in conditions of dry friction and ensure manufacturability of their obtaining and processing and high reliability in operation.     

The Effect of Virulence and Resistance Mechanisms on the Interactions between Parasitic Plants and Their Hosts

Parasitic plants have a unique heterotrophic lifestyle based on the extraction of water and nutrients from host plants. Some parasitic plant species, particularly those of the family Orobanchaceae, attack crops and cause substantial yield losses. The breeding of resistant crop varieties is an inexpensive way to control parasitic weeds, but often does not provide a long-lasting solution because the parasites rapidly evolve to overcome resistance. Understanding mechanisms underlying naturally occurring parasitic plant resistance is of great interest and could help to develop methods to control parasitic plants. In this review, we describe the virulence mechanisms of parasitic plants and resistance mechanisms in their hosts, focusing on obligate root parasites of the genera Orobanche and Striga. We noticed that the resistance (R) genes in the host genome often encode proteins with nucleotide-binding and leucine-rich repeat domains (NLR proteins), hence we proposed a mechanism by which host plants use NLR proteins to activate downstream resistance gene expression. We speculated how parasitic plants and their hosts co-evolved and discussed what drives the evolution of virulence effectors in parasitic plants by considering concepts from similar studies of plant–microbe interaction. Most previous studies have focused on the host rather than the parasite, so we also provided an updated summary of genomic resources for parasitic plants and parasitic genes for further research to test our hypotheses. Finally, we discussed new approaches such as CRISPR/Cas9-mediated genome editing and RNAi silencing that can provide deeper insight into the intriguing life cycle of parasitic plants and could potentially contribute to the development of novel strategies for controlling parasitic weeds, thereby enhancing crop productivity and food security globally.     

Comparative Proteomic Analysis of the Mesenchymal Stem Cells Secretome from Adipose,Bone Marrow,Placenta and Wharton’s Jelly

Mesenchymal stem cells (MSCs) have the potential to be a viable therapy against various diseases due to their paracrine effects, such as secretion of immunomodulatory, trophic and protective factors. These cells are known to be distributed within various organs and tissues. Although they possess the same characteristics, MSCs from different sources are believed to have different secretion potentials and patterns, which may influence their therapeutic effects in disease environments. We characterized the protein secretome of adipose (AD), bone marrow (BM), placenta (PL), and Wharton’s jelly (WJ)-derived human MSCs by using conditioned media and analyzing the secretome by mass spectrometry and follow-up bioinformatics. Each MSC secretome profile had distinct characteristics depending on the source. However, the functional analyses of the secretome from different sources showed that they share similar characteristics, such as cell migration and negative regulation of programmed cell death, even though differences in the composition of the secretome exist. This study shows that the secretome of fetal-derived MSCs, such as PL and WJ, had a more diverse composition than that of AD and BM-derived MSCs, and it was assumed that their therapeutic potential was greater because of these properties.